Instruction Manual EVO

Instruction Manual

EVO® series Scanning Electron Microscope

®

EVO Scanning electron microscope Original instructions Carl Zeiss Microscopy GmbH Carl-Zeiss-Promenade Carl-Zeiss-Prom enade 10 07745 Jena, Germany [email protected] www.zeiss.com/microscopy

Carl Zeiss Microscopy Ltd. 509 Coldhams Lane Cambridge CB1 3JS UK © by Carl Zeiss Microscopy Ltd. Document name: Instruction Manual EVO Revision: en03 Effective from: December 2013 354706-0780-006 This document or any part of it must not be translated, reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information or retrieval system. Violations will be prosecuted. The use of general descriptive names, registered names, trademarks, etc. in this document does not imply, even in the absence of a specic statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Software programs will fully remain the property of Carl Zeiss Microscopy. No program, documentation or subsequent upgrade thereof may be disclosed to any third party, unless prior written consent of Carl Zeiss Microscopy has been procured to do so, nor may they be copied or otherwise duplicated, even for the customer’s internal needs apart from a single back-up copy for safety purposes Due to an ongoing process of improvement Carl Zeiss Microscopy reserves the right to make modications of this document without notice.

Contents

Table Table of c ontents 1. Abo ut th is manual man ual ............... ........................ ................. ................. ................. ................ ................ ................. ................. .............. ...... 9 1.1. Safety in st ruct ru ct ions io ns in th is manu al .......... ................. .............. ............... ............... ............... ............... .............. .......... ... 10 1.2. Typo graphi gr aphi cal conv enti ons .............. ..................... .............. ............... ............... .............. .............. .............. .............. .......... ... 11 1.3. Defin Defin it ion io n of o f t erms .............. ...................... ............... .............. .............. ............... ............... .............. ............... ............... .............. ......... .. 12

2. Safety ................. .......................... ................. ................. ................ ................ ................. ................ ................ ................. ................ .............. ....... 13 2.1. Intended Int ended use us e .............. ..................... ............... ............... .............. .............. .............. ............... ............... .............. .............. ............... ............. ..... 13 2.2. 2.2. Preventio n o f accid ents and o f imp rop er us e ........ ........... ....... ........ ....... ....... ........ ....... ....... ........ ........ .... 13 2.3. Safety summ su mmary ary .............. ..................... .............. ............... ................ ............... .............. ............... ............... .............. .............. ............. ...... 14 2.3.1. Hazards related to personal injury ........................................................ ......................................................................... ................. 14 2.3.2. Hazards not related to personal injury ................................................................... 17 2.3.3. Fire risk summary .................................................................................................. .................................................................................... .............. 19

2.4. Safety equi pment pm ent .............. ..................... .............. .............. ............... ............... .............. ............... ............... .............. ............... ............ .... 20 2.4.1. Safety devices ....................................................................................................... ................................................................................................... .... 20 2.4.1.1. Protective cover panels ............................................................................................. ................................................................................................. .... 20 2.4.1.2. Column interlock............................................................................................................ 20 2.4.1.3. Vacuum interlock system ........................................................................................... .............................................................................................. ... 20 2.4.1.4. Beam deceleration kit interlock system ......................................................................... 21 2.4.1.5. Main circuit breaker ......................................................................... ....................................................................................................... .............................. 21 2.4.1.6. Main shut-off valves ........................................................................ ...................................................................................................... .............................. 21

2.4.2. Safety labels ............................................................... .......................................................................................................... ........................................... 21 2.4.2.1. At the rear of the electron optical column (with optional Ion Pump system only) .......... 22 2.4.2.2. At the rear of the instrument.......................................................................................... 23 2.4.2.3. Inside SEM ....................................................................................................... .................................................................................................................... ............. 24

3. Descrip Descr ip ti on ................ ......................... ................. ................ ................ ................. ................. ................ ................. ................. .............. ...... 25 3.1. Overv iew ............... ...................... .............. ............... ............... .............. ............... ................ ............... .............. ............... ............... .............. ......... .. 25 3.1.1. EVO® MA and LS .................................................................................................. ........................................................................ .......................... 26 3.1.2. EVO®HD ................................................................. ............................................................................................................... .............................................. 26

3.2. Con tr ol element s .............. ...................... ............... .............. ............... ............... .............. ............... ............... .............. ............... ............ .... 27 3.2.1. SmartSEM® user interface .................................................................................... .......................................................................... .......... 27 3.2.2. Dual joystick .......................................................................................................... ......................................................... ................................................. 28 3.2.3. Optional control panel ....................................................... ........................................................................................... .................................... 29

3.3. Pri Pri ncip nc iple le of oper atio n .............. ..................... .............. ............... ............... .............. ............... ............... .............. .............. ............ ..... 30 3.3.1. Vacuum system .......................................................... ..................................................................................................... ........................................... 30 3.3.1.1. High Vacuum mode....................................................................................................... 32 3.3.1.2. Variable Pressure mode................................................................................................ 33 3.3.1.3. Extended Pressure mode.............................................................................................. 35 3.3.1.4. Pressure ranges and apertures..................................................................................... 36

3.3.2. Specimen stage .............................................................. ..................................................................................................... ....................................... 38 3.3.3. Electron optics ....................................................................................................... 39 3.3.4. EVO® column Optibeam modes ............................................................................ 41

Instruction Manual EVO ® en03

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Contents

3.3.5. Signal detection ..................................................................................................... ................................................................................................... .. 43 3.3.5.1. Principles of detection................................................................................................... detection................................................................................................... 44 3.3.5.2. ET-SE detector (SE detector) ............................................................... ....................................................................................... ........................ 46 3.3.5.3. VPSE G3 detector (optional)......................................................................................... (optional)......................................................................................... 51 3.3.5.4. (HD)BSD detector (optional) .................................................................................. ......................................................................................... ....... 53 3.3.5.5. CL detector (optional).................................................................................................... (optional).................................................................................................... 54 3.3.5.6. STEM detector (optional) .............................................................................................. 55

3.4. Speci fi cati on ............... ....................... ............... .............. ............... ............... .............. .............. .............. .............. ............... ............... ...........56 ....56 3.4.1. EVO® ............................................................... ..................................................................................................................... ...................................................... 56 3.4.2. EVO®HD .......................................................................... ................................................................................................................ ...................................... 57

3.5. Technical data .................................................................................................58 3.5.1. Layout and connections ............................................................ ........................................................................................ ............................ 58 3.5.2. System layout ........................................................................................................ ................................................................................................... ..... 59 3.5.3. Installation requirements ....................................................................................... ........................ ............................................................... 60

3.6. Options ............................................................................................................62 3.7. Cust omer om er serv ic e ............... ...................... .............. ............... ............... .............. ............... ............... .............. ............... ............... ...........62 ....62

4. Trans port po rt and an d stor st or age ................ ........................ ................. ................. ................ ................ ................. ................. ............. ..... 63 4.1. Transport .........................................................................................................63 4.2. Storage ............................................................................................................64

5. Instal Ins tallat latio io n ................ ......................... ................. ................ ................ ................. ................. ................ ................ ................ ................. ......... 65 6. Operat io n ............... ........................ ................. ................ ................ ................. ................. ................. ................ ................ ................. ........... ... 67 6.1. Swit chin ch ing g on the th e SEM .............. ..................... ............... ............... .............. .............. .............. .............. ............... ............... ............67 .....67 6.2. 6.2. Startin g th e SmartSEM SmartSEM® us er i nt erfac e ............... ...................... .............. .............. ............... ............... ............68 .....68 6.3. Finding your way in the SmartSEM ® user interface ....................................70 6.3.1. Showing or hiding toolbars ........................................................ .................................................................................... ............................ 70 6.3.2. Showing or hiding the data zone ...................................................... ........................................................................... ..................... 71 6.3.3. Showing and hiding a full screen image ................................................................ .................................... ............................ 71 6.3.4. Using Docking panels ............................................................................................ .......................................................................................... .. 72 6.3.5. Openi Opening ng the Panel Configuration bar ........................................... .................................................................... ......................... 74

6.4. Obtai ning ni ng a f ir st image im age .............. ..................... ............... ............... .............. .............. .............. .............. ............... ............... ...........75 ....75 6.4.1. Preparing the specimen holder .............................................................................. 76 6.4.2. Loading the specimen chamber ................................................ ............................................................................ ............................ 77 6.4.3. Locating the specimen ................................................. .......................................................................................... ......................................... 81 6.4.4. Switching on the gun .......... .................................................................... ................................................................................... ......................... 82 6.4.5. Switching on the EHT ............................................................................................ .......................................... .................................................. 83 6.4.6. Generating, optimising and saving images ................................................... ............................................................ ......... 85 6.4.6.1. Generating an image..................................................................................................... image..................................................................................................... 85 6.4.6.2. Optimising the image ............................................................................ .................................................................................................... ........................ 87 6.4.6.3. Saving the image .......................................................................... .......................................................................................................... ................................ 90

6.4.7. Using automated or semi-automated functions ..................................................... 91 6.4.7.1. Using the auto saturation function................................................................................. function................................................................................. 91

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6.4.7.2. Using the auto gun alignment function .......................................................................... 92 6.4.7.3. Using the auto aperture alignment function................................................................... 93 6.4.7.4. Using the drift correction function.................................................................................. 94 6.4.7.5. Using the sample type selection function ...................................................................... 96 6.4.7.6. Using the image navigation function ............................................................................. 98 6.4.7.7. Using the automated image acquisition function........................................................... 99

6.5. Setting SEM con diti ons ............................................................................... 104 6.5.1. Consider the properties of the specimen ............................................................. 104 6.5.1.1. Guide to SEM operating parameters........................................................................... 105

6.5.2. Selecting the operation mode .............................................................................. 107 6.5.3. Changing the pressure mode .............................................................................. 109 6.5.3.1. Changing to HV mode ................................................................................................. 109 6.5.3.2. Changing to Variable Pressure configuration from High Vacuum configuration ......... 110 6.5.3.3. Changing to Extended Pressure mode ....................................................................... 112 6.5.3.4. Aligning Easy VP......................................................................................................... 113 6.5.3.5. Changing from EasyVP to Variable Pressure mode ................................................... 118 6.5.3.6. Changing from EasyVP to Extended Pressure mode ................................................. 118 6.5.3.7. Changing from VP mode / EP mode to EasyVP ......................................................... 119 6.5.3.8. Measuring the specimen current (probe current monitor) ........................................... 119

6.5.4. Setting detection parameters .............................................................................. 121 6.5.4.1. Selecting a detector..................................................................................................... 121 6.5.4.2. Using the SE detector ................................................................................................. 122 6.5.4.3. Using the BSD detector (optional)............................................................................... 122 6.5.4.4. Other optional detectors .............................................................................................. 129

6.5.5. Imaging wet specimens with the Peltier coolstage .............................................. 130 6.5.5.1. Fitting the Peltier coolstage ......................................................................................... 130 6.5.5.2. Purging the chamber ................................................................................................... 141 6.5.5.3. Obtaining an image in EP mode.................................................................................. 144 6.5.5.4. Setting SEM parameters for imaging the specimen in wet mode................................ 144

6.6. Usin g th e help functi ons ............................................................................. 146 6.6.1. Calling the SmartSEM ® help ............................................................................... 146 6.6.1.1. Printing help texts........................................................................................................ 146 6.6.1.2. Bringing help texts to the foreground .......................................................................... 146

6.6.2. Calling the context-sensitive help ........................................................................ 147 6.6.3. Searching for a topic ........................................................................................... 147 6.6.4. Using the step-by-step guides ............................................................................. 148 6.6.4.1. Getting started............................................................................................................. 148 6.6.4.2. Frequently used operation sequences ........................................................................ 148

6.6.5. Calling the short cuts help ................................................................................... 149 6.6.6. Showing information about SmartSEM® ............................................................. 150 6.6.6.1. Version history............................................................................................................. 150 6.6.6.2. About SmartSEM®....................................................................................................... 150

6.7. Fini shing the work sessi on ......................................................................... 151 6.7.1. Tungsten Emitter ................................................................................................. 151 6.7.2. LaB6 Emitter ........................................................................................................ 151


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6.8. Closin g th e SmartSEM® user interface ......................................................152 6.8.1. Logging off ........................................................................................................... 152 6.8.2. Exiting .................................................................................................................. 152

6.9. Swit ching off t he SEM as a matt er of rou ti ne ............................................153 6.9.1. Changing to STANDBY mode ............................................................................. 153 6.9.2. Changing to OFF mode ....................................................................................... 154

6.10. Swit chin g off in an emerg ency ..................................................................155 6.10.1. Switching on again after an emergency off ....................................................... 155

6.11. Switc hi ng off t he SEM completel y ............................................................156

7. Maintenance and repair ........................................................................... 159 7.1. Change of Consumables and Chemicals ...................................................160 7.1.1. Adjusting the isolation mounts ............................................................................. 161 7.1.2. Replacing the tip seal of the pre-vacuum pump .................................................. 162 7.1.3. Replacing filaments ............................................................................................. 163 7.1.3.1. Replacing pre-aligned tungsten filaments................................................................... 164 7.1.3.2. Replacing tungsten filaments (not pre-aligned) - cleaning, maintenance & alignment 174 7.1.3.3. Replacing LaB6 filaments ........................................................................................... 184 7.1.3.4. Replacing LaB6 filaments with tungsten filaments...................................................... 198

7.2. Basic pr eventiv e maintenance perfo rmed by the operato r ...................... 215 7.2.1. Checking for safe operation ................................................................................. 215 7.2.2. Cleaning up the PC ............................................................................................. 215 7.2.3. Initialising the stage ............................................................................................. 215 7.2.4. Servicing the pre-vacuum pump .......................................................................... 216 7.2.5. Baking out the gun and the chamber .................................................................. 216 7.2.6. O-ring maintenance ............................................................................................. 217 7.2.6.1. Checking the Column O-ring....................................................................................... 217 7.2.6.2. Checking the chamber door O-ring............................................................................. 218

7.2.7. Cleaning the firing unit ......................................................................................... 220 7.2.7.1. Cleaning the filament holder ....................................................................................... 223 7.2.7.2. Cleaning the Anode..................................................................................................... 224

7.3. Preventi ve maintenance perfor med by a ZEISS servi ce representativ e . 227 7.4. Repair .............................................................................................................228 7.4.1. Replacing the chamber door O-ring .................................................................... 228 7.4.2. Checking the circuit breakers .............................................................................. 230

8. Tro ub leshoot in g ....................................................................................... 231 9. Shutd own and disposal ........................................................................... 233 9.1. Putti ng t he SEM out o f operatio n ................................................................233 9.2. Disposal .........................................................................................................233 9.2.1. Disposing of solid waste (consumables) ............................................................. 233 9.2.2. Disposing of the SEM .......................................................................................... 234

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Contents

10. Parts and to ol s ....................................................................................... 235 10.1. Imp or tant cons umables ............................................................................. 235 10.2. Impo rt ant s pare parts ................................................................................ 236 10.3. Option al so ft ware l icences ........................................................................ 236 10.4. Tools and acces sori es ............................................................................... 236

11. Abbr eviations ......................................................................................... 237 12. Glossary .................................................................................................. 239 13. Declar ation of con fo rmit y ...................................................................... 241 14. Index ........................................................................................................ 243


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VIII


1. About this manual

1. About this manual This instruction manual is considered to be part of the scanning electron microscope (SEM). Read the instructions carefully. Keep the instruction manual near the SEM and hand it over to future owners of the instrument. This instruction manual is designed for users who have been trained to operate the SEM by an authorised ZEISS service representative. Operators of the SEM must not deviate from the instructions provided in this document. Reference to related documents

For details on optional equipment refer to the respective manuals delivered with the SEM. You will find these manuals in a plastic bag. For detailed information regarding the operating software refer to the Software Manual SmartSEM®. For details on technical data refer to the documents Product Specification and Installation Requirements.

At a gl ance

This instruction manual contains the following chapters:

1. About this manual

Explains function and structure of this instruction manual

2. Safety

Summarises important safety details

3. Description

Describes structure and principle of operation of the SEM

4. Transport and storage

Gives details on transport and storage

5. Installation

Refers to ZEISS service representative

6. Operation

Introduces fundamental operating procedures

7. Maintenance and repair

Describes preventive maintenance and repair tasks

8. Troubleshooting

Summarises troubleshooting methods

9. Shutdown and disposal

Summarises notes on shutdown and disposal

10. Parts and tools

Lists consumables, spare parts, tools, and accessories

11. Abbreviations

Alphabetical list of abbreviations used in this instruction manual

12. Glossary

Alphabetical list of important technical terms

13. Declaration of Conformity

Important declaration

14. Index

Alphabetical list of key words that are referred to in this instruction manual


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1. About this manual Safety instructions in this manual

1.1. Safety ins tru ctio ns in t his manual The safety instructions in this manual follow a system of risk levels, that are defined as follows:

DANGER This safety symbol and signal word indicates an imminently hazardous situation. Disregarding this warning WILL result in death or serious injury.

WARNING This safety symbol and signal word indicates a potentially hazardous situation. Disregarding this warning COULD result in death or serious injury.

CAUTION This safety symbol and signal word indicates a potentially hazardous situation. Disregarding this warning MAY result in minor or moderate injury.

CAUTION This signal word used without a safety symbol indicates a potentially hazardous situation. Disregarding this warning MAY result in property damage.

IMPORTANT This symbol and signal word draws your attention to important and useful information.

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1. About this manual Typographical conventions

1.2. Typographi cal conventi ons For the description of software, the following typographical conventions are used:

Typography

Meaning

Push .

Push the ENTER key on the keyboard.

Type

Type key 1 first, then type key 2 on the keyboard.

Type .

Simultaneously type CTRL key, AL T key and DEL key on the keyboard.

Click the Magnification icon. Select File/Exit from the menu.

Icons, buttons, and menus are printed in bold.

Enter 10 kV in the EHT target field.

Values to be selected are printed in italics.


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1. About this manual Definition of terms

1.3. Defin itio n of terms The following terms are used in this instruction manual:

SEM

Scanning Electron Microscope. EVO ® is a SEM.

SmartSEM®

Operating software for ZEISS scanning electron microscopes.

ZEISS service representative

Specially trained service expert, either ZEISS staff or authorised service partner of ZEISS.

Operator

A trained person, who is assigned to operate the SEM. Basic operator: Person who has been trained to perform fundamental operation sequences. Advanced operator : Technically skilled person who has in addition been trained to perform basic maintenance tasks.

User

A person or organisation that uses the SEM.

This instruction manual refers to the operating software SmartSEM ® v05.07.

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2. Safety Intended use

2. Safety 2.1. Int ended us e The SEM is a microscope that scans a focused beam of electrons across the specimen to generate an image. The SEM is suited to analyse surface structures and near-surface structures of appropriate specimens. For that purpose the specimen has to be located in the specimen chamber with controlled pressure environments. Commercial use only

The SEM is to be used in a laboratory environment for commercial purposes only. Do not use the SEM for any other purpose. Use the SEM only as instructed in this manual.

Using the SEM for any other purpose is not allowed and could be hazardous.

2.2. Prevention o f accidents and of impr oper use

CAUTION Risk of injury or damage due to improper operation of the SEM. Read the user documentation carefully. Do not operate the SEM until you have completely read and understood this instruction manual and the entire user documentation delivered with the SEM. You will find the user documentation in a plastic bag.

Operator training

Within the scope of initial start-up the ZEISS service representative will deliver a basic operator training. The basic operator training consists of fundamental operation procedures including safety instructions. An introduction to basic maintenance tasks will be given for an administrator of the system. The training performed shall be documented appropriately. Special application training is offered on request.

IMPORTANT Any persons undertaking maintenance, service and repair tasks not described in this instruction manual have to be authorised ZEISS service representative.


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2. Safety Safety summary

2.3. Safety s umm ary Follow the safety instructions given in this instruction manual. T his is essential to prevent damage and to protect yourself and others against accidents and unsafe practices. Do not deviate from the instructions provided in this instruction manual. This section summarises possible hazards and recommended safety procedures.

2.3.1. Hazards r elated t o p ersonal i njur y Service tasks

DANGER Danger to life: Hazardous voltage inside the SEM. Only service engineers trained and authorised by ZEISS service representative are allowed to service the SEM.

WARNING Magnetic fields can interfere with medical implants. Ion getter pumps generate a magnetic field that can interfere with medical implants, such as cardiac pacemakers. The magnetic field is also present if the SEM is switched off. When performing any maintenance tasks at the column, such as replacing filaments, it is possible to get close to the ion getter pumps and their magnetic field. If you have a medical implant fitted, always keep a safety distance of ≥ 10 cm to the ion getter pumps.

WARNING Magnetic fields Strong magnetic fields can disturb electronic devices like heart pacemakers or impair their function. Maintain a safety distance of ≥ 10 cm between the magnet and the heart pacemaker.

Radiation protection

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X-rays are produced within the SEM during operation. This is unavoidable since accelerated electrons hit material thus generating radiation.



WARNING Radiation hazard: X-rays are generated inside the SEM during operation. Only authorised ZEISS service representatives are allowed to service the SEM. Do not remove any parts. Do not disable any parts of the interlock system. Use genuine ZEISS parts exclusively. Observe all safety and X-ray protection regulations.

In the UK, the operation of the SEM is permission-free as the following requirements are fulfilled:

• •

The acceleration voltage is limited to 30 kV. The local dose rate at a distance of 0.1 m from the accessible surface of the SEM does not exceed 1 µSv/h.

• A respective label is attached to the SEM. Outside the UK, the user of the SEM has to comply with the local regulations of the country where the SEM is operated. The SEM is equipped with several radiation protection devices, which ensure - under regular operation conditions - that the SEM operates in accordance with German X-ray protection regulation (RöV) as well as with the EC Directive 96/29/EURATOM.


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Electrical connections

CAUTION High leakage current Ensure proper grounding. Do not operate the SEM without separate ground connection.

Gases

Gaseous dry nitrogen is used to vent the specimen chamber during specimen exchange. Compressed air is used to operate several valves and the auto levelling system.

CAUTION Suffocation hazard due to lack of oxygen, since the specimen chamber is vented with gaseous nitrogen. Inhaling nitrogen may cause unconsciousness. During specimen exchange, keep the chamber door open as short as possible. Avoid inhaling the air from within the specimen chamber. Ensure the area around the SEM is sufficiently ventilated.

IMPORTANT Concerning the hazards of nitrogen installations and associated safety precautions refer to guideline IGC Doc 44/xx/E: Hazards of inert gases, published by EIGA (European Indus- trial Gases Association) which can be found on the EIGA homepage www.eiga.org/Publi- cations/Documents. Check regularly if new documents concerning nitrogen installations have been uploaded.

CAUTION Risk of injury or damage due to the high internal pressure in gas cylinders (e.g. cont aining nitrogen or compressed air). Observe all safety labels on the gas cylinders and all safety instruction given by the gas cylinder manufacturer.

Operation

There are risks of injury and of damage to equipment if you operate the SEM incorrectly.

CAUTION Risk of injury Fingers could be trapped in the moving specimen stage. Always close the chamber door before you move the specimen stage.

CAUTION Pinch hazard when closing the chamber door. Use the recessed grip to close the chamber door. Ensure not to get your fingers caught in the chamber door gap.

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CAUTION Risk of damage to environment due to aggressive or toxic chemicals. When disposing of waste that has been generated during a service operation (e.g. used rotary pump oil) comply with all national and local safety and environmental protection regulations.

IMPORTANT We recommend to observe regulations for ergonomic work environment, such as environmental and local health and safety rules (VDU work place assessment). You should maintain a healthy posture and take regular breaks.

Maintenance procedures

LaB6 only: Baking out the gun head has to be performed as a regular maintenance procedure and when needed. Only advanced operators are allowed to perform the bakeout procedure.

CAUTION Burn hazard Some parts inside the SEM will get hot during the bakeout procedure. Do not place any combustible objects on the top of the electron optical column. Only authorised ZEISS service representatives is allowed to service the equipment. Dis- connect power and let surfaces cool before opening.

CAUTION Burn hazard The firing unit gets hot during operation. Allow time to cool before handling during exchange procedure.

2.3.2. Hazards no t r elated to person al inj ury

CAUTION Risk of property damage SEM or specimen could be damaged if specimen stage is at a short working distance when opening the chamber door. Always move specimen stage to a long working distance before opening the chamber door.


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CAUTION Risk of property damage Connect ZEISS-approved equipment only. Ensure the total load connected to the SEM does not exceed 10 A.

IMPORTANT Fingerprints can cause vacuum leaks. Always wear lint-free gloves when touching the specimen or inner parts of the specimen chamber.

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2.3.3. Fire r isk summ ary In case of fire, small amounts of fumes may be emitted from various materials within the SEM. In summary, it can be stated that there is only a low probability of fire originating from the SEM.


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2. Safety Safety equipment

2.4. Safety equ ipm ent 2.4.1. Safety devices In order to prevent any risk of hazard to human health or of property damage, the SEM is equipped with several safety and protective devices.

2.4.1.1. Protecti ve cov er panels Plinth, electron optical column and specimen chamber are secured with protective cover panels.

WARNING Hazardous voltage inside the SEM. Contact may cause burn or electric shock. X-rays are generated inside the SEM during operation. Do not remove any parts. The SEM must not be operated with removed protective cover panels.

2.4.1.2. Column interlock The column interlock switches off the EHT. This interlock was introduced at the end of 2010 and is not optionally available for older EVO ® models.

2.4.1.3. Vacuum interlock system The vacuum interlock is an internal interlock. It ensures that the gun vacuum and the system vacuum are better than the required thresholds.

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2.4.1.4. Beam deceleration kit interlock system Several hardware and firmware measures ensure safe operation of the beam deceleration kit. A vacuum switch, the turbo pump signal and the CAN bus communication are being checked before a stage bias potential can be applied.

2.4.1.5. Main cir cui t b reaker The Main circuit breaker is located at the rear of the plinth. It switches the mains electrical power of the SEM.

2.4.1.6. Main shu t-off valves The user is responsible for the installation of main shut-off valves at the site of installation. The following main shut-off valves are required:

•

nitrogen supply

The main shut-off valves have to be easily accessible. They must close off the connections to the corresponding media when needed. The main shut-off valves have to be lockable in their OFF position in order to prevent accidental re-activation. As the user is responsible for installing the main shut-off valves, he/she should also provide instructions how to operate the main shut-off valves properly.

2.4.2. Safety labels Appropriate safety labels on the SEM warn you of possible hazards. Each safety label is fixed near the point where a particular hazard exists.

Do not remove labels from the SEM. If damage occurs to any label(s) so that you cannot read it fully, contact ZEISS to request a new label. Fit the new label in place of the damaged label.


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2.4.2.1. At the rear of the electron opti cal column (with opt ional Ion Pump sy stem only)

B C D

Position

Subject

B

Safety information

Label

CAUTION Hot Surface Skin burns under contact. Do not touch. This area may get hot.

C

Safety information

WARNING Hazardous voltage inside Contact may cause electric shock or burn. Disconnect power before opening.

D

Safety information

CAUTION Magnetic Field Interaction with metallic objects may produce pinch hazards. Persons with medical implants keep back 12 inches.

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2.4.2.2. At t he rear of th e instr ument

E

F

Position

Subject

E

Legal information

F

Safety information

Label

CAUTION X rays produced when energized The microscope should be approved by the national regulations. Do not remove any parts.


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2.4.2.3. Insi de SEM Underneath the cover panels of the SEM there are some more safety labels, which are addressed to authorised ZEISS service representatives. These safety labels are described in the documents for ZEISS service representative.

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3. Description Overview

3. Descripti on 3.1. Overview

5

4

3 6

2

1

1

ON/STANDBY/OFF button

4

Electron optical column, EVO® column

2

Plinth

5

Monitors

3

Specimen chamber

6

SEM control computer

Fig. 3.1: EVO ® system overview


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3. Description Overview

3.1.1. EVO® MA and LS The EVO® series microscopes are divided into two groups:

•

The EVO® MA (Material Analysis) microscopes provide, as standard, the capability to use variable pressure (VP) operation.

•

The EVO® LS (Life Sciences) microscopes are environmental SEMs providing, as standard, the capability to prevent dehydration artefacts in the microscopy of life sciences specimens.

3.1.2. EVO®HD EVO®HD is equipped with a high brightness source, a LaB6 emitter, that increases the gun brightness at low accelerating voltages. Images taken at 1 kV appear 100 times brighter than a standard tungsten and 10 times brighter than a standard LaB6 source. This is achieved with a factory pre-aligned firing unit that is supplied by ZEISS. The operation of a HD gun is almost identical to tungsten and LaB6, any user familiar with the standard EVO® family of machines will operate the HD gun by simply changing probe current and acceleration voltage as required. All EVO® series microscopes provide the possibility to use the EasyVP feature (except EVO ®18 SEMs); the ability to seamlessly switch between High Vacuum and Variable Pressure. EasyVP allows using the mid-column 20 μm aperture as the beam defining aperture. The aperture is aligned using focus wobble in both High Vacuum and Variable Pressure. This enables the use of all Optibeam modes when operating the SEM under Variable Pressure conditions. A maximum pressure of 133 Pa can be achieved using any of the charge compensating gases, air or water.

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3. Description Control elements

3.2. Control elements 3.2.1. SmartSEM® user int erface The SEM is controlled by the SmartSEM ® software. The software is operated via a graphical user interface.

navigation

checkbox

tab

toolbar

box

caption bar

icon

menu bar

data zone

drop-down list

radio button

Panel Configuration bar

panel

slider

status bar MiniBar

annotation bar


image area

mouse assignment

arrow button

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3.2.2. Dual joystick The dual joystick is used for stage control and specimen navigation.

The large joystick on the right is used to drive X- and Y-axis. The stage rotation is controlled by turning the upper knob to the left or to the right. The small joystick on the left is used to control the Z axis and the stage tilt (T).

All axes are deflection-compensated: When the joystick is only moved slightly, the respective axis will move slowly. However, major movements of the joystick will result in a faster movement of the stage. The X-, Y-, and Z-axes are magnification-compensated. When working at a low magnification, the stage moves relatively fast. At higher magnifications the stage movement is slower. The different axes can also be moved simultaneously.

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3.2.3. Opti onal co ntr ol p anel The control panel is optionally available. It integrates a full sized keyboard and allows direct access to 14 of the most frequently used functions on the SEM. The following functions are available through:

Knobs

Push buttons

•

Magnification (1)

•

Reduced (2 )

•

Stigmator X (3)

•

Wobble (6 )

•

Stigmator Y(4)

•

Freeze (8 )

•

Gun Tilt X [EVO] or Aperture X [EVO HD] (5 )

•

Exchange (10 )

•

Gun Tilt Y [EVO] or Aperture Y [EVO HD] (7 )

•

Resume (11)

•

Scan Rotate (9)

•

Camera (13)

•

Shift X (12 )

•

Scan Speed - / + (17 )

•

Shift Y (14)

•

Brightness (15 )

•

Contrast (16 )

•

Focus (18 )

7

5 4

6

9 8

11 10

13 12 14

15 16

3 2 1

17 18

IMPORTANT All these functions are available via the SmartSEM ® software and can be controlled by appropriate mouse movement and MACRO execution.


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3. Description Principle of operation

3.3. Prin cipl e of op eration The SEM uses a beam of electrons to generate an image or to analyse the specimen. The electron beam scans the specimen surface.

3.3.1. Vacuum s yst em For operation of the SEM, gun head (1), column and specimen chamber have to be under vacuum. The vacuum is essential to operate the gun and to prevent collision of electrons with gas molecules.

1 2

3

4

5 6 7 8

1

Gun head

5

CSOV (chamber shut off valve)

2

Penning gauge

6

Vent valve

3

Chamber

7

Rotary pump

4

TIV (turbo isolation valve)

8

Turbo pump

Fig. 3.2: Schematics of th e vacuum sys tem System vacuum

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Rotary pump (7 ) and turbo pump (8 ) pumps the specimen chamber. The system vacuum is measured by a Penning gauge (2 ). As long as the detected pressure in the specimen chamber has not reached the operating target, the chamber shut off valve ( 5 ) is closed.



Gun vacuum

An ion getter pump is used to keep the gun area under high vacuum ( 2 ). The vacuum in the gun head is called ’Gun vacuum’. It should be well below 5 x 10 -7 mbar. The specimen holder is fitted in the chamber on the stage dovetail part when the chamber is at air (3). The specimen can be exchanged after selecting the Vent command via the SmartSEM® user interface.

Venting

When receiving the Vent command, venting gas flows into the specimen chamber via the vent valve (6 ). As soon as the pressure equilibrium is obtained, the chamber door can be opened to change the specimen.

Pumping to Vacuum

In order to continue operation, the Pump command pumps the specimen chamber using the prepump (rotary) and turbo. As soon as the vacuum in the specimen chamber is ready for operation, ’EHT Vac ready’ message appears in the SmartSEM® user interface. Gun and EHT can then be switched on.


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3.3.1.1. High Vacuum mode The 20 µm or 30 µm mid-column apertures are used for the beam profile control in High Vacuum configured EVO® systems (no pressure limiting aperture is fitted under the SEM pole piece). In EVO® systems with HV configuration all Optibeam modes such as resolution, field, depth, fisheye and analysis modes can be used for imaging. However, the SEM can only be operated under High Vacuum conditions for imaging conductive specimens. The configuration of the SEM needs to be changed to Variable Pressure mode in order to image non-conductive specimens.

1

2 3

Both gun and chamber are at high vacuum (1). DPA (differential pumping aperture)(2 ). Isolation valve (3) open. Benefits

Ap pl ic ati on

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• •

Provides the means to obtain higher resolution Enables using the SE detector

High Vacuum mode is the regular operation mode for standard applications.



3.3.1.2. Variabl e Pressur e mod e The Variable Pressure (VP) mode enables imaging specimens that are non-conducting, strongly outgassing, or humid, without the need for vapour deposition or other preparation procedures. This is made possible by using a differential pumping system which allows partial pressures above 10 Pa to be set in the specimen chamber while maintaining high vacuum in the gun area. VP conditions can be achieved if the microscope is configured for the Variable Pressure or the EasyVP mode (when the 100 µm aperture or the 750 µm aperture are, respectively, fitted under the SEM pole piece). Variable PresThe VP 100 µm aperture is fitted under the final lens when the SEM is configured for VP. The 750 sure configura- µm mid-column aperture is used for imaging in this configuration. The beam first goes through tion the 750 µm mid-column aperture and then passes through the 100 µm VP aperture (pressure lim-

iting aperture) before landing on the specimen surface. In VP configuration, only the Normal and Analysis Optibeam modes can be used for imaging. It is though possible to switch between HV and VP modes when using this configuration. The maximum pressure that can be achieved in the VP configuration is 400 Pa for EVO ® W systems, 273 Pa for EVO® LaB6 and EVO®HD SEMs. EasyVP config - In the Easy VP configuration, the EasyVP, 750 µm aperture, is fitted under the final lens and the uration 20 µm mid-column apertures is used for the beam control. In the EasyVP configuration, the beam

first goes through the 20 µm mid-column aperture and then passes through the 750 µm EasyVP aperture (pressure limiting aperture) before landing on the specimen surface. The maximum pressure that can be achieved in the EasyVP configuration is 133 Pa for all EVO ® series SEMs. Optibeam modes such as resolution, field, depth, fisheye and analysis modes can be used for imaging, in the EasyVP configuration. It is possible to switch between HV and VP modes and the beam alignment is optimum in both conditions without changing any gun or column parameters.


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Operating principle

The residual gas atmosphere in the specimen chamber creates an interaction region of electrons and residual gas molecules between the final lens and the specimen. In this region, high-energy electrons in the primary electron beam hit the residual gas molecules and ionise them. The ions generated in these collisions contribute to the compensation of negative charge on the specimen. However, another effect of these collisions is to scatter the electron beam. This is called the ‘skirt effect’. The electrons that are lost from the primary beam by this effect provide only a resolutionlimited background signal for imaging purposes. Although it is possible to tolerate these leakage losses at chamber pressures up to a few hundred Pa, it is necessary to carefully select and control the important factors such as acceleration voltage, chamber pressure and beam path. Although operating in VP mode compensates for the charging effects, the increased chamber pressure reduces the signal-to-noise ratio. This can be compensated by using the noise suppression features of SmartSEM®.

1

3 2 4

Water vapour kit (de-ionised) Can be nitrogen or air

Gun at high vacuum (1). Chamber at variable pressure (2 ). Single DPA (differential pumping aperture) fitted in the bottom of objective lens; Variable Pressure (100 µm aperture) or EasyVP (750 µm aperture) ( 3) Isolation valve closed (4).

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3.3.1.3. Extended Press ure m ode Extended Pressure (EP) mode is required for imaging hydrated specimens. This will enable the study of hydrated specimens in their native state with little or no loss of water in the SEM (the specimen is kept fully hydrated during the pump down). This pressure mode is typically used with a Peltier Coolstage. When the SEM is configured for EP, the 750 µm mid-column aperture is used and the EP 100 µm aperture is fitted under the final lens in combination with one of the BeamSleeves™ (500 µm or 1000 µm apertures). For achievable pressure ranges, refer to section 3.3.1.4.

1

+

or

2 3 4

5

Gun at high vacuum (1). Chamber at extended pressure (2 ). Two differential pumping apertures are fitted in the bottom of the objective lens (3). Isolation valve closed (4). The rotary pumps are directly pumping the chamber (5 ).


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3.3.1.4. Pressure r anges and apertur es

SEM

Application

MA 10 MA 15 MA 25

Charge compensation

Hardware

Min/Max pressure*

Filament

10-400 Pa

W

10-273 Pa

LaB6

10-400 Pa

W + LaB6

Min/Max pressure*

Filament

VP aperture

Charge compensation + EasyVP VP aperture

Charge compensation + Improved image quality + High accuracy EDS analysis

+ EP aperture

500 µm

Table 3.1: MA: Charge compensati on

SEM

Application

MA 10 MA 15 MA 25

Hydrated specimen imaging

Hardware

+ EP aperture

or 500 µm or 1000 µm

500 µm or 1000 µm

10 – 1000 Pa (1000 µm) 10 – 3000 Pa (500 µm)

W + LaB6

Table 3.2: Extended Pressure MA: Dynamic processes

SEM

Application

MA 10 MA 15 MA 25

Charge compensation

Hardware

Min/Max pressure*

Filament

10-400 Pa

W

10-273 Pa

LaB6

10-400 Pa

W + LaB6

VP aperture

VP aperture

Charge compensation + Improved image quality + High accuracy EDS analysis

+ EP aperture

500 µm

Table 3.3: LS: Charge comp ensation

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SEM

Application

LS 10 LS 15 LS 25

Hydrated specimen imaging

Min/Max pressure*

Hardware

+ EP aperture

or 500 µm or 1000 µm

500 µm or 1000 µm

10 – 1000 Pa (1000 µm) 10 – 3000 Pa (500 µm)

Filament W + LaB6

Table 3.4: LS: Hydr ated specimen i maging

* Both air and water vapour can be introduced, as a charge compensating gas, into the chamber.

Mid-column click aperture

The mid-column click aperture assembly design allows using 4 apertures. However, only three apertures are fitted as standard. The position of each aperture is marked, as shown below, on the mid-column aperture assembly.

Ap ert ur e Pos it io ns

Hard war e

Ap ert ur e Size

EVO® 0

750 µm (used in combination with VP aperture or Easy VP aperture)

1

30 µm

2

20 µm

3

Blank (apertures can be fitted as an option)

EVO®HD 0

750 µm (used in combination with VP aperture or Easy VP aperture)

1

20 µm

2

20 µm

3

Blank (apertures can be fitted as an option)

Table 3.5: Mic-column click aperture


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3.3.2. Specimen stage Standard specimen stage is a 5-axes motorised Cartesian stage that is controlled by the SmartSEM® software. The stage can be operated by the dual joystick controller or by using the soft joystick in the SmartSEM ® user interface. The five axes are called:

X

X-axis

Y

Y-axis

Z

Height

R

Rotation

T

Tilt

The focus on the Cartesian stage is not maintained when the specimen is tilted. This can be compensated for by using the Compucentric function in SmartSEM®.

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3.3.3. Electro n op tic s The EVO® column is the area of the SEM, where electrons are emitted, accelerated, deflected, focused, and scanned. Main characteristics of the EVO ® optics are the condensor and objective lenses.

1 2 U EHT 3

4 5

6

7 8

1

W or LaB6 cathode

5

Scanning and stigmator coils

2

Gun alignment and emission display coils

6

Objective lens with through the lens pumping

3

Double condensor system

7

BSD (backscattered electron detector) or HD BSD (optional High Definition backscattered electron detector)

4

Mechanical mid-column aperture changer

8

Specimen

Fig. 3.3: Schematics of th e electron optic s

Gun

The filament is heated by applying the filament current. Electrons are emitted from the heated filament.

EHT

The emitted electrons are accelerated by the acceleration voltage ( UEHT).

Gun alignment and display coils

The electron beam is centred by the gun alignment and emission coils ( 2 ).


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Condensers

A double condenser system (3) allows the continuous regulation of the probe current.

Ap ert ur es

The electron beam passes through the currently selected aperture in the mechanical mid-column aperture changer (4) to ensure optimum quality of beam is maintained.

Scanning and stigmator coils

The scanning coils (5 ) move the electron beam in a point-by-point scan over the specimen surface. The stigmator coils (5 ) compensate for astigmatism, so that the electron beam becomes rotationally symmetrical.

Objective lens

The electron beam exits the objective lens (6 ).

Signal detection

When the primary electron beam hits the specimen, certain interaction signals are generated, which are recorded by various detectors, such as the CZ BSD ( 7 ).

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3.3.4. EVO® col umn Optibeam modes The EVO® column offers the following Optibeam modes :

Optibeam modes

Characteristics

An aly si s mo de

The specimen remains in focus for any change in probe current.

Field mode

A larger field of view for navigation and a large depth of field.


Beam path

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Optibeam modes

Characteristics

Resolution mode

Smallest probe diameter for a chosen probe current at any working distance or keV.

Depth mode

Largest depth of field for a chosen probe current, at any working distance or keV.

Fisheye mode

Largest field of view for navigation and a very large depth of field.

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Beam path



3.3.5. Signal detection The interaction products most frequently used for the generation of images in scanning electron microscopy are secondary electrons (SE) and backscattered electrons (BSE).

Detected signals

Typical application

SE detector (Everhart-Thornley)

SE2

Topography and surface structure.

VPSE G3 detecto r

SE

Variable pressure applications. Topograohy and surface structure (on VP systems only).

Optional detectors

Detected signals

Standard detectors

Typical application

Backscattered electron detectors, including 4-quadrant BSD, 5-segment BSD (optional), HDBSD (option al)

BSE

Topographical (crystal orientation), atomic number contrast.

Cathodoluminescence (CL) detector

Light photons

Mineralogy

Scanning Transmission Electron Micr oscop y (STEM) detector

Transmission electrons

Transmission imaging of thin sections in biological and mineralogical examinations.

Specimen current detector

Absorbed electrons

Electron beam induced current (EBIC).

EPSE (needle and rin g)

SE*

Extended pressure applications. Typically when imaging biological specimens in a fully hydrated form.

*By means of measuring current produced by ionisation of gas by SE Electrons generated around specimen surface.

IMPORTANT For more details, refer to the document Product Specification EVO ® .


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3.3.5.1. Principles of detection When a primary electron (PE) beam hits a specimen, certain electron beam interaction processes occur. Secondary electrons (SEs) and backscattered electrons (BSEs) are then generated. Specific types of detectors are able to detect the SEs and BSEs, and the detector signals can be used to create images and produce information about the properties of the specimen. Secondary electrons

Secondary electrons are ejected from the outer atomic shell of the specimen material upon impact by the primary electron beam.

Fig. 3.4: Interaction between primary electron b eam and sp ecimen

The three main categories of secondary electrons are based on the origin of the secondary electrons and on the distance from the PE impact point, where they leave the specimen.

•

SE1 electrons are generated and leave the surface of the specimen directly at the spot where the primary electron beam impacts on the specimen surface.

•

SE2 electrons are generated after multiple scattering inside the interaction volume, and leave the specimen at a greater distance from the primary beam’s impact point.

•

SE3 electrons are generated by backscattered electrons colliding with the chamber walls or the lens system.

Secondary electrons have low energy (less than 50 eV).

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Backscatter electrons

All electrons with energy higher than 50 eV are known as backscattered electrons (B SEs). BSEs are generated by elastic scattering in a much deeper range of the interaction volume and carry depth information. The backscatter coefficient increases with increasing atomic number of the elements within the specimen. This allows the BSE detector to generate atomic number contrast-, or compositional contrast images.

Fig. 3.5: Backscattered electron co efficient against atomic number


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3.3.5.2. ET-SE detector (SE detector) The ET-SE-, or the Everhart-Thornley-, detector is mounted on the wall of the specimen chamber-, and is therefore classed as a ‘chamber detector’. Due to its position in the chamber, the SE detector views the specimen laterally. The SE detector allows detection of secondary electrons with a small backscattered component. Secondary electrons moving towards the detector are attracted by the collector and are directed towards the scintillator accelerated by the scintillator voltage.

4

3 1

2

1

Specimen

3

SE detector

2

Collector grid

4

Objective lens with through the lens pumping

Fig. 3.6: Schematics of t he SE detector

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Operating principle

When the high energy electrons hit the scintillator layer ( 2 ), photons are generated inside the scintillator.These photons are directed towards the light pipe ( 3) and are transferred to the photomultiplier (5 ). The photomultiplier multiplies the flashes of light and outputs a signal that can be used for imaging. 4 3

5

2

1

1

Collector

4

Specimen chamber wall

2

Scintillator

5

Photomultiplier

3

Light pipe

Fig. 3.7: Operating prin ciple of the SE detector

Collector bias voltage

The Detectors tab of the SEM Contr ols panel allows adjusting the collector bias voltage in the range of -250 V to +400 V in steps of 1 V. This voltage generates a bias in front of the detector. The bias attracts the low energy SE electrons and accelerates them towards the detector. For allstandard applications the collector bias voltage is usually set to 300 V. It is also possible to set the collector bias voltage to a negative value. This generates a field that deflects the secondary electrons, preventing them from reaching the scintillator and contributing to the signal. Backscattered electrons are not affected significantly by the negative bias voltage and reach the scintillator to contribute to image information. This allows the generation of a ‘pseudo-backscattered image’, which shows enhanced topographical information. Surface images that show enhanced topographical information can also be generated using BSE detectors, but they do not show the shadows that can be created using the SE detector.


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•

When using a positive collector bias voltage, surfaces that are tilted in the direction of thedetector are emphasised, but there are no shadowing effects.

+300 V collector bias voltage

•

When using a negative collector bias voltage, the image shows enhanced topographical contrast, which arises mainly from the extreme shadowing effects. However, the fine surface details are less visible.

-150 V collector bias voltage

Ap pl ic ati on s

The SE detector can be used in the complete high-voltage range.

The working distance has a significant effect on the efficiency of the SE detector. Shadowing effects occur when the working distance is too short. If the specimen is too close to the final lens, most of the electrons will be deflected by the field of the electrostatic lens or move to the final lens itself. This means they cannot be detected by the SE detector. Depending on the specimen material and on the specimen geometry, a minimum working distance of approximately 4 mm should be used. Extreme signal loss is likely to occur if shorter working distances than this are used. Conversely, the SE detector is very good when used for imaging at long working distances. This is particularly important for low magnification imaging that is necessary for adjusting the orientation of the specimen holder or locating a specific area on the specimen.

Optimal initial settings

The following settings provide a good field of view for navigating on the specimen at low magnifications:

• Initial working distance in the range of 10 mm to 20 mm. • Acceleration voltage of approximately 10 kV.

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Parameter

Value

Recommended conditions

Accelerat io n vol tage

100 V to 30 kV

In principle suitable for the entire high-voltage range.

1 kV to 5 kV

Low-voltage applications for the compensation of charges and for surface-sensitive imaging.

5 kV to 20 kV

Average voltage range. Suitable for many different applications.

20 kV to 30 kV

Voltage range frequently used for analytical purposes.

5

If the working distance is too short, shadowing effects will occur which diminish the efficiency of the detector. Below 20 kV, the SE electrons are absorbed by the field of the electrostatic lens.

Working distance

Collector voltage

mid-column aperture

mm

4 mm to 6 mm

For low-voltage applications (1 kV to 5 kV).

6 mm to 12 mm

Useful for the average voltage range (5 kV to 20 kV).

12 mm to 30 mm

Recommended only for low magnifications and to increase the depth of field.

300 V

Standard value of the collector voltage.

0 V to 400 V

Variation of the collector voltage at high magnifications to obtain the mixed signal.

-150 V to 0 V

For pseudo- BSE images.

HV: 20 µm

30 μm

VP/EP: 750 µm

Recommended for high magnification and high resolution imaging. The standard aperture is recommended for many applications.

For VP/EP mode only.

Table 3.6: Recommend ed setting s for im aging wi th th e SE detector


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Parameter

Value

Recommended conditions

Specimen tilt

Tilting the sample towards the detector increases collection efficiency.

Operation mod e

Only suitable in high vacuum.

Table 3.6: Recommended setti ngs fo r imagin g with t he SE detector

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3.3.5.3. VPSE G3 detector (optional) The variable-pressure secondary electron (VPSE G3) detector is designed to generate images that are similar to those produced by SE detectors, but in the variable pressure (VP) mode. The secondary electrons generated on the specimen are attracted to the VPSE G3 detector (voltage applied by the VPSE G3 collector bias). Secondary electrons that are emitted from the specimen collide with the residual gas molecules (nitrogen, air or water). Collisions between SEs and gas molecules can ionize the molecules, releasing further electrons and resulting in further collisions (an ‘ion cascade’). This process amplifies the SE signal-, and also results in the generation of photons. The signal source for the VPSE G3 is not the SEs themselves, but the photons (secondary products) that are produced during this process.

1

1

VPSE G3 detector

Fig. 3.8: Schemati cs o f th e VPSE G3 detector Chamber pressure

When using a VPSE G3 detector, it is important to remember that a certain pressure is required in the specimen chamber to generate enough photons to be detected. If the number of residual gas molecules is too low, the collision probability and therefore the efficiency of the detector reduces. Depending on the specimen used and the operating parameters, optimum detection occurs in the pressure range of 20 Pa to 60 Pa.

IMPORTANT Increasing the chamber pressure also increases the scattering process, and reduces the resolution of the SEM. It is therefore essential to find optimum conditions for each particular application.


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Dwell ti me

Another key parameter is the length of time that the primary electron beam dwells on the specimen. If this dwell time is too short at a fast scan rate, there is not sufficient time for an ion cascade to develop or for the residual gas molecules to generate the imaging photons. This reduces the detector efficiency. If the dwell time is too long at a slow scan rate, very high energy is applied to the specimen per time unit. This can result in charging artefacts on the obtained images. Optimum scan rate for different specimens might vary and can only be determined by experiment.

IMPORTANT To reduce charging effects, use the Frame Averaging function in SmartSEM ® . This function uses fast scan speeds and increases the number of frames.

Collector bias

The collector bias sets the electric field between the specimen and the VPSE G3 detector. If the collector bias is too low, the VPSE G3 detector efficiency is significantly reduced. Too high collector bias values result in saturation of the VPSE G3 detector depending on the specimen, the acceleration voltage, the probe current and the pressure in the specimen chamber.

This in turn results in very bright periodic lines on the image that prevent proper specimen imaging.

IMPORTANT The banding effects can be eliminated by reducing the collector bias or by reducing the pressure in the specimen chamber. There is also a calibration dialog available that can help you to further improve the image quality (Tools/Goto Panel/VPSE-G3 Calibration).

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3.3.5.4. (HD)BSD detecto r (opti onal) The BSD/HDBSD is a semiconductor detector that has four or five silicon diode segments. When high energy backscattered electrons hit the different segments, electron-hole pairs are generated in these segments. The separation of charges and the current in each segment can be measured and used to generate an image. There is a thin layer deposited on the surface of each diode segment, which the backscattered electrons must pass through before they reach the diode. Due to the presence of this layer, the BSD can only produce images above a certain electron energy threshold. The emission of backscattered electrons from a specimen is related to the atomic number of the material involved; the higher the atomic number, the higher the backscatter coefficient. When imaging, regions containing elements with higher atomic number appear brighter than those containing lower atomic numbers.

The HDBSD is a highly sensitive BSD detector avialable with either four or five diode segments. The HDBSD provides the ability to visualise exceptionally fine surface detail in high contrast using low incident beam energies.

Four segment BSD

Appl ic ati on s

Five segment BSD

Materials Analysi s

• • • • • •

Metallurgical sections Geological sections Complex materials Printed circuit boards Semiconductors Bond pads

Life sciences

• •

Mineral deposits in plant structures Bone structures


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3.3.5.5. CL detect or (opti onal) The cathodoluminescence detector is an inclined detector that allows efficient visible or ultraviolet light collection.The CL detector is ideal for use in geology, mineralogy and materials science applications where it can help in internal structural examination of rocks, ceramics and semiconductors. The specimens, however, need to emit light when interacting with the primary electron beam. Differences in crystal structure or the presence of impurities in a cathodoluminescent material result in variations in the energy gap between the filled valence bands and the empty conduction bands, and consequently a change in the CL emission. The light (photons) emitted from the specimen is collected by the CL detector and converted to signal for imaging. The CL detector is fully integrated into the SEM’s automatic brightness and contrast control and can be used simultaneously with any of the detectors without degrading their performance. The detector can be used during EDS and wavelength-dispersive spectrometer (WDS) measurements, at any valid magnification.

IMPORTANT For detailed information on EVO applications please search for Electron & Ion Beam Microscopy on www.zeiss.com/microscopy and select Applications.

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3.3.5.6. STEM detector (opti onal) The STEM unit consists of a diode electron detector positioned under an electron transparent thin specimen in a pre-aligned holder which fits directly on the specimen stage. The STEM unit enables positioning of the thin specimen close to the objective lens which improves resolution. The collected signals are equivalent to bright field imaging. Using the STEM detector in Variable Pressure mode enables the possibility to explore the nanostructure of non-conducting specimens.

1

2

1

STEM specimen holder

2

STEM Detector

Fig. 3.9: Schematics of the STEM detector


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3. Description Specification

3.4. Specification 3.4.1. EVO®

Essential specifications

EVO® MA 10 and LS 10

Field of View

< 7 - 1,000,000 x

< 5 - 1,000,000 x

8.5 mm AWD and 35° take-off angle Resolution, Depth, Analysis, Field, Fisheye 10 - 400 Pa (MA Series) 10 - 3000 Pa (LS Series)

Pressure Range

Avail abl e Detec to rs

< 5 - 1,000,000 x

6 mm at the Analytical Working Distance (AWD)

X-ray Analysi s OptiBeam modes

EVO® MA 25 and L S 25

3 nm (2 nm) @ 30 kV - SE and W (LaB 6) 3.5 nm @ 30 kV - SE VP mode with W 15 nm @ 30 kV - 1nA, LaB6 20 nm (15 nm) @ 1 kV - SE and W (LaB 6) 10 nm @ 3 kV - SE

Resolution

Magnification

EVO® MA 15 and L S 15

BSD – Multisegment Diode ETSE – Everhart-Thornley Secondary Electron Detector VPSE – Variable Pressure Secondary Electron Detector SCD – Specimen Current Detector STEM – Scanning Transmission Electron Microscopy Detector CL - Cathodoluminescence Detector

Chamber

310 mm (Ø) x 220 mm (h)

365 mm (Ø) x 275mm (h)

420 mm (Ø) x 330 mm (h)

5-Axes Motor ised Specimen Stage

X = 80 mm Y = 100 mm Z = 35 mm T = 0 - 90° R = 360° (continuous) Stage control by mouse or optional joystick and control panel



Maximum Specimen Height

100 mm (with the ZTR module removed)



Future Assured Upgraded Paths fo r MA Series Image Framestor e System Control Utility requirements

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BeamSleeve®, Extended Pressure, Water vapour VP gas

max. 3072 x2304 pixel, signal acquisition by integrating and averaging SmartSEM®** GUI operated by mouse and keyboard Windows® 7 multilingual operating system 100 - 230 V, 50 or 60 Hz single phase, no water cooling requirement


3. Description Specification

3.4.2. EVO®HD

Essential specifications

Resolution

EVO®HD MA 15

EVO®HD MA 25 1.9 nm @ 30 kV SE 3 nm @ 30 kV SE VP mode 10 nm @ 30 kV 1 nA 5 nm @ 3 kV SE 8 nm @ 1 kV SE

Magnification

< 5 - 1,000,000 x

Field of View

Maximum 6 mm at the Analytical Working Distance (AWD) of 8.5 mm

X-ray Analys is OptiBeam modes Pressure Range

Avail abl e Detec to rs

8.5 mm AWD and 35° take-off angle Resolution, Depth, Analysis, Field, Fisheye 10 - 273 Pa 10 - 400 Pa (with optional TTL upgrade) BSD – Multisegment Diode ETSE – Everhart-Thornley Secondary Electron Detector VPSE – Variable Pressure Secondary Electron Detector SCD – Specimen Current Detector STEM – Scanning Transmission Electron Microscopy Detector CL - Cathodoluminescence Detector

Chamber

365 mm (Ø) x 275 mm (h)

420 mm (Ø) x 330 mm (h)

5-Axes Motor ised Specimen Stage

X = 130 mm Y = 130 mm Z = 50 mm T = -10° - 90° R = 360° (continuous) Stage control by mouse or optional joystick and control panel

X = 125 mm Y = 125 mm Z = 50 mm T = -10°- 90° R = 360° (continuous) Stage control by mouse or optional joystick and control panel

Maximum Specimen Height



Future Assured Upgraded Paths f or MA Series Image Framestore System Control Utility requirements

BeamSleeve®, Extended Pressure, Water vapour VP gas

max. 3072 x2304 pixel, signal acquisition by i ntegrating and averaging SmartSEM®** GUI operated by mouse and keyboard Windows® 7 multilingual operating system 100 - 230 V, 50 or 60 Hz single phase, no water cooling requirement

IMPORTANT For more details refer to the document Product Specification EVO ® .


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3. Description Technical data

3.5. Technical d ata 3.5.1. Layout and conn ection s

C

D

B E

A I

F

II

III

IV

I

Static vibration damper

A Mains power supply 208...230V/25A, 1/N(L2)/PE

II

Pre-vacuum pump

B Equipotential bonding bar

III Computer workplace

C Pressure reducer (water, nitrogen, compressed air)

IV Emergency Off (EMO) button (optional)

D Main shut-off valves

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E

Nitrogen supply

F

Exhaust line



3.5.2. System layout

1 2

2

1

1

Size (mm) No

Description

approx. length x width x height

approx.

Distribution of load

Footprints

Weight (kg)

1

Plinth + column

822 x 980 x 1783

860

4 x 220 kg

4 x Ø 80 mm

2

Table + PC

1148 x 980 x 1250

97

4 x 24.3 kg

4 x Ø 50mm

3

Static damping block

180 x 180 x 160

36

1 x 36 kg

-

4

Pre-vacuum pump

427 x 250 x 290

25

1 x 25 kg

-

5

EMO box (optional)

380 x 400 x 850

32

4 x 8 kg

-


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3.5.3. Install ation requir ements

Location requirements Installation site

Exclusively inside buildings

Room size

min 3.0 m x 4.0 m x 2.3 m (LxWxH)

Service area

min 1.0 m at each side

Installation category

II

Electrical supplies Nominal AC voltage

100-240V 50/60 Hz Single Phase

Protection class

I

Nominal frequency

50 - 60 Hz

Power consumption

2 kVA-3 kVA, dependent on accessories

Circuit breaker

25 A

Ampere interrupting capacity AIC

minimum 10,000 A

Protective ground

High leakage currents can be present in the SEM. Therefore, the SEM has to be connected to an equipotential bonding bar. An exclusive grounding connection to earth must be provided, i.e. the grounding terminal must not be common to other electrical equipment. A grounding wire AWG10 (5 m long) is delivered with the SEM.

Cross section

> 4 mm2

Ground resistance

< 0.1 Ohm

Gas supplies Nitrogen Flow rate

max. 40 l/min for ventilation of specimen chamber with chamber door open

Pressure

0.2 to 0.3 MPa (2.0 to 3.0 bar)

Quality

4.6 with nitrogen content <99.996 %

Compressed air

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Flow rate

less than 1l/min

Pressure

0.5 - 0.6 MPa (5 - 6 bar)

Quality

oil-free



Environmental requirements Ambient Temperature

approx. 23°C +/-1°C Stability

0.5°C/h

Relative humidity

Less than 65 %

Altitude

Maximum 2000 m above sea level

Pollution degree

2

IMPORTANT Also refer to the documents Product Specification EVO ® and Installation Requirements EVO ® .


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3. Description Options

3.6. Option s A range of options and accessories is available for use with the EVO ® SEM. Examples of the available options and accessories are as follows:

• Detectors – VPSE, BSD/HDBSD, CL, STEM, SCD • Additional Chamberscope or Stubscope • Specimen holders and stage accessories, including Coolstage, Right-hand tilt, Faraday cup • Software add-ins and enhancements • Column maintenance kit, O-ring kit For full details of the available options and accessories, please contact your local ZEISS service representative or sales representative.

3.7. Cust omer s ervice For customer service, please contact your local ZEISS service representative. A list of ZEISS locations and authorised service partners can be f ound at: www.zeiss.com/microscopy

IMPORTANT To maintain best possible performance of the SEM it is essential to perform preventive maintenance on a regular base. Moreover, it is recommended that you conclude a service contract with your local ZEISS service organisation or representative. This will ensure a continuous trouble-free operation of the SEM.

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4. Transport and storage Transport

4. Transpo rt and s torage 4.1. Transpor t

CAUTION Crushing hazard while load is being moved or lowered. Maintain a safe distance. Do not walk or place your hands or feet under the load while it is being lowered. Wear safety shoes and gloves.

CAUTION Risk of injury due to heavy components. Rotary pumps and vibration blocks are heavy and can cause injuries when lifted by one person alone. Be careful when transporting the rotary pump and the vibration block. At least two people are required to lift the rotary pump or the vibration block.

CAUTION Risk of damaging the SEM The SEM may only be transported in air-suspended vehicles. Moving parts must be secured during transport to prevent them from slipping or tipping over. Avoid rocking the crates back and forth. Devices for transporting the SEM must be rated to handle its full weight and dimensions. Note the weight information on the package and on the shipping document.

The temperature during transport has to be between -10° C and +70° C. The SEM is delivered in two containers:

Re-usable wooden box

Dimensions and weight of crate: 1950 x 1320 x 1090 mm³ (W x D x H), appr. 120 kg

Cardboard box on euro-pallet

Dimensions and weight of crate: 1910 x1220 x 1100 mm³ (W x D x H), appr. 102 kg

Check that none of the items has been damaged during shipment.


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4. Transport and storage Storage

4.2. Storage The packed SEM has to be stored in a dry place. Temperature during storage has to be between -10° C and +70° C.

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5. Installation

5. Installation Unpacking, installation and first start-up are carried out by an authorised ZEISS service representative.


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5. Installation

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6. Operation Switching on the SEM

6. Operatio n At a gl ance

This chapter contains information about:

• • • • • • • • • • • •

Switching on the SEM Starting the SmartSEM® user interface Finding your way in the SmartSEM ® user interface Obtaining a first image Setting SEM conditions Imaging wet specimens using the Peltier coolstage Using the help functions Finishing the work session Closing the SmartSEM® user interface Switching off the SEM as a matter of routine Emergency off (EMO) Switching off the SEM completely

6.1. Switc hing on the SEM

1

Press the ON push button.

The green ON button lights up.


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6. Operation Starting the SmartSEM® user interface

6.2. Start ing the SmartSEM® user i nterface Preconditions:

• •

The SEM is switched on.

1

Select Start/All Programs/SmartSEM/SmartSEM User Interface or click the SmartSEM ®

The Windows® operating system has been loaded.

icon on the desktop, if available.

The EM Server opens while loading various software and firmware. The function of the EM Server is to implement the internal communication between software and hardware of the SEM.

The EM Server Log On dialogue appears. 2

Enter your user name and password.

3

Confirm by clicking OK .

The SmartSEM® user interface opens.

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6. Operation Starting the SmartSEM® user interface

The EM Server is minimised to a small element (icon) on the right side of the Windows ® task bar.

Now, the SmartSEM® software is ready to operate the SEM.


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6. Operation Finding your way in the SmartSEM® user interface

6.3. Finding your way in the SmartSEM® user int erface 6.3.1. Showing or hiding toolbars Several toolbars such as user toolbar, status bar, and annotation bar are available for easy access to the SmartSEM ® functions.

1

Select View/Toolbars from the menu. Alternatively, type .

The Toolbar Views panel is shown.

2

If you wish to show a toolbar, tick the respective checkbox.

3

To change the tooltip features of the user toolbar, select the respective radio button on the right hand side of the panel.

4

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Confirm by clicking OK .



6.3.2. Showing or h idi ng t he data zone The data zone is used to display current parameters. You can also include a micron marker to show the base magnification. The default toolbar is shown below.

1

Select View/Data Zone/Show Data Zone from the menu. A tick is shown to indicate that the function is activated. Alternatively, type to toggle the data zone.

6.3.3. Showin g and hidi ng a full screen image You can take advantage of the full monitor size by showing a full screen image. The maximum size of the image is fixed at 1024 x 768 pixels. 1

Select View/Toggle Full Screen Image from the menu. Alternatively, type .

To undo the function, type .


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6.3.4. Usin g Dock ing panels It is possible to dock various control panels onto the main window. The purpose of the docking panel is to keep the area of the image completely clear, as the docking panel is outside the main image display.

1

To show the docking panel select View/Toolbars from the menu.

2

Tick the Docking Panel checkbox.

The docking panel is shown on the right hand side of the image area.

3

To move a docking panel to the docking area, pick up the panel by clicking the title bar and drag and drop it into the docking area.

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4

To stick a control panel to the docking panel, click the title bar of the control panel and drag it to the docking panel.

The panel becomes integrated into the docking panel.

You can place several control panels in the docking panel. 5

To minimise a panel, click the arrow button in the title bar.


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6

To hide the docking panel, a

select View/Toolbars from the menu.

b

untick the Docking Panel checkbox.

The docking panel is hidden.

6.3.5. Opening the Panel Conf igu ration bar 1

From the menu bar, select Tools/Goto Panel . Alternatively, click the arrow button at the side of the image area.

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2

The Panel Configuration bar opens showing an alphabetical list of functions.

3

To select a function, double-click it.


6. Operation Obtaining a first image

6.4. Obtaining a fi rst image The following section summarises basic sequences to quickly obtain an image using the SE detector. To simplify the procedure, the method described mainly uses SEM Contro ls panel and status bar functions.

Prerequisite:

•

At a gl ance

SmartSEM ® has been started and is ready to control the SEM.

Parts required

No.

Allen key, 1.5 mm

delivered with the SEM

stub


tweezers for specimen


specimen holder


if necessary: carbon tape, conductive carbon, adhesive metal tape or similar

-

appropriate specimen (with conducting properties e.g. gold on carbon)

-

lint-free gloves

-

The complete sequence includes:

• • • • • • • •

Preparing the specimen holder Loading the specimen chamber Locating the specimen Switching on the gun Switching on the EHT Generating an image Optimising the image Saving the image


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6.4.1. Preparing the sp ecimen h older IMPORTANT Contamination caused by fingerprints can lead to vacuum deterioration or prolonged pumping times. Always wear lint-free gloves when touching specimen, specimen holder or stage. 1

Attach the specimen to the stub by using conductive carbon, adhesive metal or carbon tape. Ensure that the specimen area to be analysed is in good contact with the stub. This will ensure high electrical conductivity between the specimen and the stub.

2

Use the tweezers to insert the stub into the specimen holder.

3

Use the Allen key to tighten the location screw and secure the specimen.

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6.4.2. Loading t he specim en chamber 1

Click the ChamberScope icon in the toolbar. This can also be achieved by pressing the Camera button on the hard front panel

(optional).

A TV view inside the specimen chamber is shown.

CAUTION Risk of damaging the objective lens and/or your specimen Ensure not to hit the objective lens while driving the stage. Change to TV mode to observe the moving stage.


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2

On the SEM Controls panel on the right hand side of the user interface, select the Vacuum tab.

3

Click Vent to vent the specimen chamber.

A message appears asking: ’Are you sure you want to vent?’. 4

Confirm by clicking Yes . The specimen chamber is filled with gaseous nitrogen.

CAUTION Suffocation hazard due to lack of oxygen, since the specimen chamber is vented with nitrogen. After the specimen exchange, keep the chamber door open as short as possible. Avoid inhaling the air from within the specimen chamber. Ensure the area around the SEM is sufficiently ventilated.

5

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Take hold of the recessed grip.



6

Slowly open the chamber door.

IMPORTANT Contamination caused by fingerprints can lead to vacuum deterioration or prolonged pumping times. Always wear lint-free gloves when touching specimen, specimen holder or stage. Keep the chamber door open as short as possible. All specimen holders are fitted with a dovetail fitting so that the position of the specimen holder is exactly defined. 7

Mount the specimen holder: a

Make sure that you place the dovetail fitting in the correct orientation onto the holding device on the specimen stage.

b

Make sure that the flat side of the dovetail fitting of the specimen holder is flush with the milled edge of the stage.

Milled edge of the stage Flat side of dovetail

8

When closing the chamber door check the chamber scope to ensure the specimen does not hit any components when it is introduced into the specimen chamber.


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CAUTION Pinch hazard when closing the chamber door. Use the recessed grip to close the chamber door. Ensure not to get your fingers caught in the chamber door gap.

9

Carefully close the chamber door.

10 Click Pump in the SEM Control panel.

11 A change macro is also available which automates the sample change procedure and prompts the user to carry out specific actions. The final steps of the macro runs up the electron beam ready for the user to start imaging.

The vacuum status messages show the current vacuum levels achieved.

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6.4.3. Locating the sp ecimen

1

In TV mode (ChamberScope), look into the specimen chamber.

CAUTION Risk of damaging the objective lens and/or your specimen. Ensure not to hit the objective lens while driving the stage. Watch the moving stage in TV mode.

2

Move the specimen by using the dual joystick (optional) or by calling the Soft Joystick from the menu bar.

3

Carefully move the specimen closer to the objective lens. The distance between objective lens and specimen surface should be less than about 10 mm.

IMPORTANT After loading the specimen, there is the possibility to automatically set a number of key parameters. Refer to section 6.4.7.5. for details.


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6.4.4. Switch ing on t he gun

1

In the Vacuum tab: Check that EHT Vac ready=Yes is indicated.

Alternatively, check that there is a green tick alongside Vac: in the status bar.

2

Click Gun in the status bar.

3

Select Beam On from the pop-up menu.

The gun is being run up.

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6.4.5. Swit chin g o n t he EHT ’EHT’ stands for Extra High Tension. This voltage has to be applied to the gun in order to make it emit electrons.

1

Watch the vacuum status messages on the Vacuum tab of the SEM Contro ls panel.

When the required vacuum has been reached you will see the message ’Vac Status = Ready’.

2

Select the Gun tab.

3

To set the filament current, move the FIL I Target slider or click FIL I Target = and

type in the desired value. 4

To set the acceleration voltage, move the EHT Target slider to the desired value.

Alternatively click EHT Target = and type in the desired value.


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5

Switch on the EHT: a

Click EHT in the status bar.

b

Select EHT On from the pop-up menu. The EHT will run up to the target value.

The EHT is running up to 10 kV.

The status bar buttons are merged and the Al l: button appears.

Now, the electron beam is on.

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6.4.6. Generating, op tim isi ng and savin g images The following workflow describes how to obtain images with the SEM. To make it more comprehensive, the workflow is separated into generating, optimising and saving images.

IMPORTANT The following procedures describe how to manually perform the necessary steps. There are also several automated functions available that can help you with these tasks. For details, refer to section 6.4.7.

6.4.6.1. Generating an image EasyVP is the recommended configuration when using the EVO ® series systems. EasyVP enables the use of all Optibeam modes and switching between the HV and VP conditions, allowing imaging of both conductive and insulating specimens at a maximum chamber pressure of 133 Pa. 1

Fit the Easy VP aperture.

2

Set the Optibeam mode to resolution.

3

Select the 20 micron mid-column click aperture.

4

On the Gun tab, set the EHT to 20 keV and the Iprobe to 100 pA.


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5

Turn on the beam.

6

Select the Detectors tab.

7

From the Signal A = drop-down list, select SE2.

Selecting the SE detector is recommended to obtain the first image, as this detector provides a good signal-to-noise ratio even at large working distances.

8

On the SEM Controls panel, select the Scanning tab.

9

from the drop down list, select a fast scan speed, e. g. Scan Speed = 3. The lower the scan speed number the faster the electron beam is scanned across the specimen. If the image displayed is noisy, then change the scan speed to 4 or 5 but no higher than 6 as it will slow the specimen navigation process.

10 To move the specimen stage to a suitable location for imaging, use the X and Y controls on the joystick. 11 Click the Magnification/Focus icon on the toolbar. 12 To set a low magnification e.g. Mag = 500 x , either press the left mouse but-

ton and drag the mouse or click the magnification display in the status bar to enter the magnification value. The current magnification is indicated in the status bar. Alternatively, use the Magnification knob on the control panel. 13 Set the focus: Press the middle mouse button and drag the mouse to focus. Alternatively, use the Focus knob on the control panel.

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The current working distance (WD) is indicated in the status bar. 14 If necessary change the stage Z position to set the WD to 8.5 mm. 15 Select the Detectors tab. 16 To adjust the contrast and brightness, use the Brightness and Contrast sliders.

Alternatively, use the Brightness and Contrast knobs on the control panel.

17 Select an area of interest on the specimen surface. 18 Focus on a feature of interest. 19 Readjust the contrast and brightness if necessary.

6.4.6.2. Optim isi ng th e image IMPORTANT The following procedure describes how to manually improve the image quality. There is also an automated function available that can help you with this task. For details, refer to section 6.4.7.3. 1

Set the mouse or control panel adjustment to Coarse by toggling the Coarse/Fine button in the status bar. This can also be achieved by pushing on the keyboard.

2

Select the Ap ert ur es tab.

3

Activate the Focus Wobble checkbox (1). Focus wobble is a function that sweeps the focus of the objective lens backwards and for- 1 wards through the focus on the specimen 2 plane. If the aperture is slightly misaligned, a lateral shift in the image will be observed.


3

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4

The intensity of the wobble can be adjusted by using the Wobble Amplitude slider (2 ). Set the Wobble Amplitude between 60% and 70%. Wobble speed can be accelerated by activating the Wobble Fast checkbox (3).

5

From the Panel Configur ation bar, select Ap ert ur e Al ig n . The Ap ert ur e Al ig n dialog opens.

6

To set the Ap ert ur e Alig n value to zero, click the 0 button.

7

Align the mid-column aperture by carefully ad justing the X and Y micrometer gauges to eliminate lateral image shift. The specimen should be seen to pulsate and not to shift.

8

Untick the Focus Wobble checkbox.

9

In the Scanning tab, set Scan Speed = 7 .

10 Bring the image into focus at a higher magnification than the desired final magnification. Typically double the desired magnification. 11 In the status bar, toggle to Fine mode. Use Coarse and Fine mode of adjustment where appropriate.

IMPORTANT Once the alignment is optimised, DO NOT change the position of the X and Y micrometer gauges on the mid-column click aperture. It is now possible to work at any EHT, Iprobe and working distance without the need to change the position of the X and Y micrometer gauges on the mid-column click aperture. 12 Slowly increase the magnification to the value required (e.g. Mag 50.000 x). It is prudent to refocus the image if and when required whilst increasing the magnification. 13 On the toolbar, click REDUCE. A small scan frame is shown. The image outside the scan frame is frozen.

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14 Use the mouse to change size, shape and position of the reduced raster area. 15 Focus the image in the reduced raster.

16 Select the Ap ert ur es tab and click Stigmation (1).

Alternatively use the control panel stigmation knobs or click STIG on the toolbar. 17 In the Stigmation box, use the arrow buttons or the left and right slider to obtain the sharpest possible image (2 ).

1

This is similar to focusing.

2

In order to obtain a well-focused image, it is prudent to adjust the focus and the stigmation a number of times before moving to the next stages of imaging. 18 Deactivate the reduced raster. 19 Reduce the magnification to the required value. 20 To activate auto contrast and brightness, click

3

4

LEVELS on the toolbar (4).

21 Once a steady contract and brightness level has been obtained, click the PHOTO on the toolbar (3). This runs a macro that automatically changes the scan speed to 8, the noise reduction to line integration with 4 lines and freezes the image at the end of the frame.

A red dot at the right bottom of the image area indicates that the image is frozen.


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6.4.6.3. Savin g t he im age 1

To save the image, click SAVE on the toolbar

1

2

(2 ). Alternatively, select File/Save Image. 2

To unfreeze the image, middle-click PHOTO on the toolbar (1). It is now possible to change the EHT, Iprobe and working distance to any value without changing the position of the X and Y micrometer gauges on the mid-column click aperture.

When the acceleration voltage (EHT) or the Iprobe values is changed during the imaging, use the automatic aperture align for aligning the beam (see section 6.4.7.3.). 3

Set the preferred imaging conditions (example 10 keV, 8.5 mm WD and 300 pA) and obtain an image.

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4

From the Panel Configuration bar, select the Ap ert ur e Al ig n dialog.

5

Click Au to Ap ert ur e Al ig n .



6.4.7. Using autom ated or semi-automated funct ions 6.4.7.1. Using the auto s aturation f unctio n Auto saturation is used to automatically set the correct currents for tungsten filaments. The filament current can vary depending on gun parameters such as the beam current and the accelerating voltage. The software automatically calculates and sets the filament current values for tungsten filaments at the second peak. Selecting the correct saturation values for the filament will increase the filament life time and improves the resolution of the obtained images.

IMPORTANT This functionality is only applied when using tungsten filaments. 1

On the SEM Contro ls panel, select the Ap ert ur es tab.

2

Click Au to Sat....


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6.4.7.2. Using the auto gun alignment fun ctio n Auto gun align is used to automatically align the shift and/or the tilt of the beam, to the centre of the column, using the emission image. 1

From the Panel Configur ation bar, select Gun Alignment . The Gun Alignment dialog opens.

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•

To adjust the beam tilt and to maximise the image brightness, click Coarse Alig n .

•

To adjust both the beam tilt and to shift to maximise the image resolution, click Fine Al ig n .



6.4.7.3. Using the auto apertur e alignment f uncti on Auto aperture align is used to improve the quality of the images. When the aperture align is selected the software automatically aligns the beam with respect to the Easy VP aperture.

IMPORTANT The feature is only available when the Easy VP aperture is fitted. 1

From the Panel Configur ation bar, select Ap ert ur e Al ig n .

The Ap ert ur e Al ig n dialog opens. 2

Set the preferred imaging conditions (example 10 keV, 8.5 mm WD and 300 pA) and obtain an image.

3

Click Au to Ap ert ur e Al ig n button.

The software starts aligning the beam and the progress bar appears on the panel. A full size image is displayed when the alignment is completed.


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6.4.7.4. Using t he drift correctio n fun ction Drift correction allows you to rectify any image drift. Drift of features, in the site of interest, can occasionally occur when an area is imaged over a prolonged period of time, the stag e is moved, or when reloading the specimen under investigation. The drift correction feature allows imaging of a specific feature by returning the image or the stage to the exact same position (as previously imaged). It may also be used in conjunction with other third party software to allow long exposure frame grabbing or repeated analysis of a defined specimen site. The beam shift is then modified such that the imaging area, under observation, matches the reference image. The available beam shift range depends on the imaging conditions and in turn determines the accuracy of the drift correction.

IMPORTANT This functionality requires a license. 1

From the Panel Configur ation bar, select Drift Correction .

The Drift Correction dialog opens.

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2

Select a distinct feature on the specimen.

3

Click Display Rectangle and place the rectangle around the feature or area of interest.

4

to improve the absolute accuracy of the drift correction, select a higher store resolution than



1024x768. 5

To save the reference image, click Create Reference .

6

Change the store resolution to the standard value (1024x768). The drift correction process will use the imaging conditions set when the reference was created and when it is complete the imaging settings will be restored.

7

Once the reference rectangle is selected and the reference image has been saved, click Hide Rectangle to continue working on the specimen.

If a drift or movement of the specimen is encountered during the imaging process, i.e. the distinct feature moves away from the reference area then click Do SEM Drift Corr.. This will modify the beam shift such that the area of the specimen scanned matches the original position. The command will be executed from a macro.

Parameters in the Settings group

•

Maximum Pixel Error specifies the amount of pixel mismatch the system tolerates when identifying the reference feature. The default value is 1 pixel. In general a smaller value is better as it results in higher accuracy of the drift correction. Using a value of zero can however cause the drift correction to fail to match a valid image. Using a value of 1 is recommended for most applications. This value is the minimum accuracy of a successful drift correction but the corrected drift may obviously be more.

•

Minimum Confidence specifies the system certainty in identifying a feature on the specimen as being the reference feature. Choosing too high numbers may lead to the system failing to locate the reference feature whereas choosing too low values may lead the system erroneously identifying other features as being the reference feature. The default setting is 50%.

•

Drift Maximum Tries specifies the maximum number of times that the system should loop through the drift correction algorithm in order to identify a feature that matches the reference feature. The default is 5 times but a good match is usually found in one or two tries.

•

Period Drift Correction is used when an area is imaged over a prolonged period of time and the time interval between the corrections (periods, seconds) can be predefined and entered in the field.

• Additional system and imaging conditions can be selected under the options.


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6.4.7.5. Using the sample t ype selection funct ion the sample type selection functionality enables the user to obtain an image from any specimen quickly, i.e. a reference image, without putting any effort in selecting the operating parameters (vacuum mode, accelerating voltage probe current and detector). The quality of the initial image can subsequently be improved, if necessary, by modifying the imaging parameters.

1

From the Panel Configur ation bar, select Sample Type Selection . The Sample Type Selection menu opens.

2

Select a sample type that is similar to the sample under analysis. A dialog appears asking you to provide more information about the sample under analysis.

3

Enter the relevant parameters. When the information regarding the specimen status is provided, the software runs macros that are assigned to the different specimen types, with predefined parameters and vacuum settings.

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Editing or adding new sample types

It is possible to edit or add new sample types to the Sample Type Selection menu. 1

In order to add a new sample type to the menu obtain an image from the desired specimen.

2

From the Panel Configuration bar, select Sample Type Save. The Sample Type Save dialog opens.

3

Click any of the blank boxes.

4

Add the sample type name and. If needed, edit the Parameters To Save list on the Sample Type Parameter Save dialog.

The SEM conditions, vacuum mode and imaging parameters will then be saved for the new specimen type. 5

Close the Sample Type Parameter Save dialog. The Sample Type Save dialog displays the new sample type.

6

Close the Sample Type Save dialog. You have successfully added the new sample type. It can now be selected from the Sample Type Selection menu.


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6.4.7.6. Using the image navigation function Image navigation enables easy navigation of the specimen. The sites of interest on the specimens can simply be moved under the beam by double clicking on the preferred stub. 1

Load a few specimens on a specimen holder and take a picture. You can use camera and scanned pictures as well as CAD drawings.

2

From the Panel Configur ation bar, select Image Navigation . The Image Navigation dialog opens.

3

Click on the External Image and load a camera picture of the specimen holder with specimens.

4

Turn on the beam: - 20 keV - 8.5 mm to 10 mm WD - Iprobe 200 pA or higher.

5

On the Image Navigation dialog, click Setup . Follow the wizard (defining 3 points on the specimen holder and correlating those points to the camera picture).

6

Finish the manual registration setup by selecting the Yes option in the dialog, to save the current image and registration data.

IMPORTANT It is also possible to save the Image and the specimen holder position in a different folder. 7

To save the specimen holder‘s camera picture in a chosen folder, click Save Image in the Registr ation Image section.

8

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To save the specimen holder position, click Save in the Manual Registr ation section.



Preferably, this should be the same location as the saved image.

6.4.7.7. Using the automated image acquisiti on f uncti on Prerequisites:

• •

You have completed the manual registration as described in the previous section. The automated image acquisition function requires one of the following specimen holders: - Single - Carousel8 - Single30 - Carousel9 - MSSH_12 - MicroAnalysis - 8Stub_15mm - 9Stub_26mm - FILTER_SINGLE_25MM FILTER_SINGLE_45MM - AUTO_7 - FILTER_SINGLE_25MM - 13FILTER_SINGLE_45MM - Filter_5x47mm - Filter_8x47mm Potted_4x32mm - Potted_3x32mm_1x38mm - Potted_4x30mm - Planchette_5x25mm - Potted_9x30mm Carousel9x6.5mm - Carousel8x10mm - 19 Stub Circular

Procedure: 1

From the Panel Configur ation bar, select Au to mat ed Im agi ng .


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The Au to mat ed Im agi ng dialog opens. 2

To choose a folder for saving images, click Image Directory .

3

Select the Define tab (1).

4

Click Drag (2 ).

5

To select an area, left click and drag the

1

2

mouse on the specimen. The fields of view at the selected imaging conditions (accelerating voltage, magnification and working distance) determine the size of the rectangles, i.e. the rectangle sizes cannot be larger than the field of view.

6

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To select the next stub: a

Change the stub number.

b

Drag a rectangle for each site of interest.

c

Click Ad d .



The list of regions of interests, the stub numbers and the FOV are continuously updated and can be viewed on the left side of the dialog (1). 7

1

2

If any points or regions of interests need to be changed, click Edit (2 ).

8

Select the points and/or regions of interest that need to be edited and move those points and regions to the desired positions.

9

If you want to add multiple regions (with different magnifications) to a certain point in the overview image, activate the Multi checkbox and click the point of interest in the overview image. Once you have selected different magnifications as described in the next step, you get a collection of concentric rectangles. You can switch between Multi mode and Ad d mode on a stub or stubs to build up a list any way you like.

10 To open the the Magnification list, click Magnification . This list is generally used in

combination with the spot mode and the list of preferred magnifications can easily be edited by typing the magnification values and using the arrow buttons to add or remove the values.


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11 To be able to zoom in/out using the mouse wheel, activate the Zoom checkbox. Right clicking on a stub in combination with the zoom function will display the magnified image of the whole stub in the centre of the viewing area.

12 To start the imaging/analysis: a

Select the Run tab.

b

Select the preferred detectors.

c

Click Run .

Saved images are displayed as thumbnails on the bottom of the panel. The stubs and the regions of interest are highlighted in red when under analysis and shown on the left side of the panel.

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When the analysis is completed the software displays a new message box: Ac qu is it io n Completed .


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6. Operation Setting SEM conditions

6.5. Setting SEM conditions 6.5.1. Consider t he prop erties of t he specimen Specimens that are studied in the SEM can be divided into two main categories, namely conductors and non-conductors and these will be discussed in greater detail later. However there are several factors to consider during all specimen preparation and these are given below. 1

The size and weight might necessitate some reduction of the specimen to fit holders and to ease specimen manipulation for observation.

2

Mineral and metallurgical specimens may require polishing. Etching and electropolishing may also be required.

3

The specimen should be able to withstand the vacuum of the SEM as it might become damaged or deformed.

4

The specimen should be clean and dry if it is to be used in high vacuum mode, i.e. free of dust, moisture, oils and grease, as their presence can lead to charging, contamination and longer pump down times. Otherwise use VP or EP vacuum mode.

5

Porous samples will also take a long time to pump out in high vacuum mode. Coat non-conductors to prevent charging if allowed or VP mode is not available.

6

Observation of the specimen at low kV (start at 1 kV) is another good alternative where “charge balance” can be obtained.

7

The specimen should be firmly attached to the specimen stub or holder either mechanically or by gluing. Silver dag and carbon dag can be used as conductive glues for small samples. Carbon tabs/tape are also convenient but may not provide good mechanical stability.

8

There should be good electrical connection between the surface of the specimen and specimen stub or holder for non-conductors.

9

Health and Safety procedures regarding the handling of the specimen during its preparation should be observed.

Conductive specimens are generally observed in what might be described as a conventional SEM however Non-conductive specimens are being increasingly observed in a specially modified SEM called the Variable Pressure SEM (VPSEM) where gas can be introduced into the specimen chamber. The benefit is that the specimen can be viewed without the necessity to “coat” as the negative charge built up on the surface of the non-conductive specimen by the high energy primary electrons is neutralised by the positively charged ions that are produced when the gas molecules are ionised by collisions with secondary, backscattered and primary electrons. It also slows down the dehydration of moist specimens that leads to structural collapse. However it is now possible to observe moist specimens in conjunction with cooling of the specimen and the water control option using SEMs with EP vacuum pumping modes.

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6.5.1.1. Guide to SEM operating parameters Selecting the mid-column apertures and aligning the electron beam

Optimum beam alignment is necessary for obtaining high quality images. It is therefore important to select the appropriate mid-column aperture prior to specimen imaging.

Imaging conductive specimens:

•

For EVO® systems in High Vacuum (HV) configuration use only the 20 µm or 30 µm mid-column apertures.

Imaging non-conductive specimens:

•

The 750 µm mid-column aperture is used for imaging in the variable pressure configuration. In addition, the VP 100 µm aperture needs to be fitted under the final lens.

•

In the Easy VP configuration, the EasyVP, 750 µm aperture, is fitted under the final lens and the 20 µm mid-column apertures is used.

•

EasyVP is, however, the recommended configuration when using the EVO ® series systems. EasyVP enables the use of all Optibeam modes and switching between the HV and VP conditions, allowing a maximum chamber pressure of 133 Pa. If higher chamber pressures are required for the charge compensation of non-conductive specimen, the VP mode needs to be used (allows chamber pressure of 400 Pa for EVO ® W systems and 273 Pa for EVO ® LaB6 systems).

The mid-column click aperture is used for changing the mid-column apertures. There are three apertures fitted in the assembly (20 µm, 30 µm and 750 µm) and the position of each aperture is fixed and labelled. The apertures can easily be changed by rotating the manual adjustment knob.

Suggested settings

The conditions given below are suggestions and the operator may find that different values will give better information for the types of specimens that are being investigated. MC = Mid-Column Aperture PLA = Pressure Limiting Aperture

Conductive specimens

General Microscop y

• • • • •

EHT =20 kV Iprobe = 200 pA WD = 8.5 mm Filament set to the “Long Life Mode” (select the option on the Gun tab) Filament I set to 1st peak for magnifications < 10 kx (gives longer filament life) Filament I set to 2nd peak for magnifications > 10 kx (for better resolution) Detector = SE with collector bias > + 300 V


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• •

MC = 30 μm Cycle time to reduce noise = 20

EDS

• • • • • • • • •

EHT = 20 kV for metals and minerals EHT = = 8 to 10 kV for semiconductors and organic materials Filament I set to first peak for Qualitative analysis Filament I set to second peak for Quantitative analysis Iprobe = 1000 pA or adjust for 30 % deadtime WD = 8.5 mm for a 35 ° take off (elevation) angle Detector = BSD Final aperture = 30 μm Cycle time = 20 or longer for X-ray mapping

High resolution

• • • • • • Non–conductive specimens

EHT=30 kV Iprobe = 10 pA WD = 5 mm Filament I set to 2nd peak and untick the “Lonflife Mode” MC = 20 μm Detector = SE with collector bias + 400 V Cycle time to reduce noise =1.3 mins or longer Warning – remove the BSD to its parked position

High vacuum mode

• • • • •

EHT = 1 kV Iprobe = 10 pA WD = 5 mm Filament I set to 2nd peak MC = 20 μm Detector = SE with collector bias + 400 V Use scan speed 3 with frames to average = 30 to reduce noise.

Variable pressure mo de

• • • • • • •

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EHT = 25 kV Iprobe = 250 pA WD = 8.5 mm Filament I set to 2nd peak MC = 20 μm PLA = 100 μm EasyVP aperture Detector = BSD or VPSE Cycle time = 20 sec or longer Chamber pressure = 10 Pa for BSD detector, 40 Pa for VPSE detector or adjust to eliminate charge disturbances.



Extended pressure mode for cool ed hydrated specimens

• • • • • • • • •

EHT = 30 kV Iprobe = 300 pA WD = 8.5 mm Filament I set to second peak MC = 750 μm PLA = 100 μm upper EP aperture Beam Sleeve® = 500 μm Detector = BSD or VPSE Cycle time = 20 sec or longer Chamber pressure = 650 Pa to slow dehydration Temperature of specimen to retain water at 650 Pa = 1 °C (controlled by the Peltier cool stage)

Extended pressure mode for hydr ated specimens

• • • • • • • •

EHT = 30 kV Iprobe = 300 pA WD = 5 mm Filament I set to 2nd peak MC = 750 μm PLA = 100 μm Beam Sleeve® = 500 μm Detector = BSD or EPSE Cycle time = 20 sec or longer Chamber pressure = 2500 Pa to 3000 Pa to retain water at ambient temperature (20°C to 30°C)

6.5.2. Selecting the operatio n mo de EVO® can be operated in different Optibeam operation modes, depending on the type of application. Optibeam takes the requirements for probe current, working distance, etc. and determines the optimum lens settings to achieve the best performance from the column. Some Optibeam modes might not be available when the fixed aperture is fitted. Fisheye mode requires the optional SmartSEM® software licence FISHEYE.


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1

Select the Ap ert ur es tab in the SEM Control panel.

2

Use the drop-down selection and the checkboxes to select the operation mode. These modes are accessible in HV mode

(when no aperture is fitted) or when the EasyVP aperture is fitted:

• An aly si s m od e: Specimen remains in focus for any change in probe current.

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•

Field mode: A large field of view for navigation with a long depth of field.

•

Resolution mode : Smallest probe diameter for a chosen probe current at any working distance or keV.

•

Depth mode: Largest depth of field dor a chosen probe current at any working distance or keV.

•

Fisheye mode: Extreme field of view for navigation and a very large depth of field.



6.5.3. Changin g t he pressur e mode 6.5.3.1. Changin g t o HV mod e 1

Select the Vacuum tab.

2

Click Go To HV.

After selecting HV the system will pump the chamber and open the turbo isolation valve. The chamber pressure and the system pressure will then reach the same pressure and display the same value.


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6.5.3.2. Changing t o Variable Pressure conf iguration from High Vacuum con figuration Changing t o EasyVP mode

1

Vent the chamber and remove the lens mounted BSD (if fitted) and place it in the parked position. Retract all retractable detectors.

2

Fit the EasyVP aperture (part no. 354820-9068-000).

3

Refit the lens mounted BSD detector, if fitted.

4


5

Select Change Apertures and click EasyVP Apertur e.

6

Pump the chamber and adjust the mid-column aperture by selecting the 20 μm aperture.

7

Select the Vacuum Tab.

8

Select Go To VP.

9

To select the working pressure, click the VP Target slider.

10 For suggested working parameters see section 6.5.1.

IMPORTANT For some MA EVO ® microscopes the option to select all the possible EP and VP aperture variants is not an option. When this is the case selecting the Change Apertures tab will not open the full aperture selection page but will instead toggle between No Aperture, Easy VP and VP Aperture Without Beam Sleeve ® .

IMPORTANT When using EVO ® in EasyVP mode it essential to align the beam through the 20 µm mid- column aperture. The resolution being determined by the 20 μ m mid-column aperture.

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Changing t o VP mode

1


2

Fit the VP aperture (part no. 35070-0070-0000).

3

Refit the lens mounted BSD detector if fitted.

4


5

Select Change Apertures and click VP Aperture.

6

Pump the chamber and adjust the mid-column aperture by selecting the 750 μm aperture..

7

Select the Vacuum Tab.

8

Select Go To VP.

9

To select the working pressure, click the VP Target slider.

10 For suggested working parameters see section 6.5.1.

IMPORTANT For some MA EVO ® microscopes the option to select all the possible EP and VP aperture variants is not an option. When this is the case selecting the Change Apertures tab will not open the full aperture selection page but will instead toggle between No Aperture, Easy VP and VP Aperture.

IMPORTANT When using EVO ® in VP mode it is essential to align the beam through the 750 µm mid- column aperture. The resolution being determined by the 100 µm (pressure limiting) VP aperture.


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6.5.3.3. Changin g to Extended Press ure mod e 1


2

Fit EP apertures and BeamSleeves® as appropriate.

3

Refit the lens mounted BSD detector if fitted.

4


5

Select Change Apertures and click Ap ert ur e ty pe fitted .

6

Close the Select Apertu re window.

7

Pump the chamber and adjust the mid-column aperture by selecting the 750 μm aperture.

8

Select the Vacuum tab

9

Select Go To EP.

10 Click the EP Target slide bar to select working pressure.

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6.5.3.4. Ali gni ng Easy VP This alignment step is required to satisfactory align the beam through the 20 aperture. 1

Select Tools/User Preferences...

2

Check that Au to Cali br ati on and User Align

μm

mid-column

are set to Yes.

3

After manually fitting the EasyVP aperture, select the Ap ert ur es tab and click Select Ap ert ur e.

4

Tick the EasyVP Apertur e radio button.


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5

Select the Gun tab and set EHT target to 20 kV.

6

Select OptiBeam Resolutio n from the drop-down menu.

7

Select the Gun tab and set IProbe to 100 pA.

8

Double-click WD in the data zone and set the working distance to 8.5 mm. If the data zone is not visible: a

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Select View/Data Zone/Show Data Zone.



9

Select Select the 20 micr micron on mid mid-co -colum lumn n click click aperaperture.

10 Sele Select ct the the Detectors tab and select SE1 from the Signal drop-down list.

11 Sele Select ct the the Scanning tab and select Normal Operating Mode drop-down list. from the Operating

12 Sele Select ct the the Ap ert ur es tab and select the 20.00 µm aperture from the Ap ert ur e Size drop-down list.

13 Type to carry out a C1/C2/C3 lens hysteresis removal. 14 From the men menu u bar, bar, selec selectt Beam/Gun Al ig n... and click Emission .

15 Set Emissi Emission on Zoom Zoom to to 35.


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16 Click Ap ert ur e Al ig n and click 0 to zero the aperture alignment.

17 Make sure sure that that the filament filament is saturate saturated d and set the brightness and the contrast to 50%.

18 Adjust contrast contrast to make the outer outer region of the the emission emission image visible visible around the brighter, brighter, central part of the Emission Image. It should look like a fried or poached egg.

Contrast too low

Contrast too high

Final result

19 Adjust the the brightnes brightness s and emission emission zoom to improve the visibility.

20 Adjust the emission emission image image with gun shift shift and gun tilt so that the bright bright centre is centred centred within within the emission image and that the emission image is centred on the screen.

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It is recommended to use the arrow buttons instead of the sliders for easier adjustment.

Before alignment

After alignment

21 Sele Select ct the the Scanning tab and select Normal Operating Mode drop-down list. from the Operating

22 Focus on a feature feature on the the specimen specimen and still still keep the WD to to 8.5 mm. 23 Select Select a fast fast scan scan speed speed e.g. e.g. 1. 24 On the Ap ert ur es tab, turn on the focus wobble function and use the fine adjustment screws on the mid-column aperture to align the beam. 25 To perform perform a hysteresis hysteresis correction, correction, type .

26 If necessary, necessary, repeat steps 20 to 25 25 to realign realign the beam accurately. 27 To complete complete the alignment, alignment, continue continue with with the steps steps described described in section 6.4.6.

IMPORTANT From now on do not touch or move the fine adjustments screws on the mid-column aperture assembly.


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6.5.3. 6.5.3.5. 5. Changin Changin g fr om EasyVP to Variable Pressu re mod e 1

Vent the system

2

If fitted, fitted, remove remove the the lens mounte mounted d BSD detector detector and retract retract all all retractab retractable le detectors. detectors.

3

Remov Remove e the the 750 750 µm µm Easy EasyVP VP aper apertu ture. re.

4

Inse Insert rt tthe he 100 100 µm µm VP VP-a -ape pert rtur ure. e.

5

Refi Refitt the the lens lens m mou ount nted ed BSD BSD dete detecto ctor. r.

6

Change Change the ape apertur rture e confi configur gurati ation on iin n Smart SmartSEM SEM® as described in section 6.5.3.2.

7

Pum Pu mp the the cham hamber.

6.5.3. 6.5.3.6. 6. Changin Changin g fr om EasyVP to Ext ended Pressur e mode

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1

Vent the system

2

If fitted, fitted, remove remove the the lens mounte mounted d BSD detector detector and retract retract all all retractab retractable le detectors. detectors.

3

Remov Remove e the the 750 750 µm µm Easy EasyVP VP aper apertu ture. re.

4

Inse Insert rt the the E EPP-ap aper ertu ture res. s.

5

Refi Refitt the the lens lens m mou ount nted ed BSD BSD dete detecto ctor. r.

6

Change Change the ape apertur rture e confi configur gurati ation on iin n Smart SmartSEM SEM® as described in section 6.5.3.3.

7

Pum Pu mp the cham hamber



6.5.3.7. Changin g f rom VP mode / EP mode to EasyVP 1

Vent the system

2

If fitted, remove the lens mounted BSD detector and retract all retractable detectors.

3

If present, remove existing VP or EP apertures.

4

Fit the 750 μm EasyVP aperture.

5

Refit the lens mounted BSD detector.

6

Change the aperture configuration in SmartSEM.

7

Pump the chamber.

8

Turn on the beam.

9

Follow the instructions given in section 6.5.3.4.

6.5.3.8. Measurin g t he specimen cur rent (probe cu rrent mo nitor ) The specimen current is the current flowing through the specimen. It corresponds to the total number of electrons that hit the specimen. The specimen current can be detected by means of a Faraday cup. It consists of a strongly absorbing material with a cavity covered by an aperture. Both the secondary electrons and the backscattered electrons cannot escape from the Faraday cup, so the displayed current is the same as the incident beam current. Procedure: 1

Load the Faraday cup into the specimen chamber.

2

Pump the specimen chamber.

3

Switch on the electron beam.

4

Set a magnification that allows transmission of the complete electron beam into the cavity through the aperture orifice.

5

Open the Panel Configuration bar .


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6

Double-click Specimen Current Monit or .

7

Tick the Spot checkbox.

8

Activate the SCM On checkbox.

The specimen current is measured permanently. The measured value is displayed in the field Specimen I =.

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6.5.4. Setti ng detection parameters 6.5.4.1. Selecti ng a detecto r 1

Select the Detectors tab.

2

Select the detector from the Detectors dropdown list.


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6.5.4.2. Using t he SE detector 1

Select the SE detector.

2

If required, set the collector bias by moving the Collector Bias slider. The default value is 300 V.

6.5.4.3. Usin g th e BSD detecto r (opti onal) 1

Check that the lens mounted BSD detector is fitted. If it is in the parked position, a

Remove the BSD detector from the parked position.

b

Fit the BSD in the working position.

2

Carefully close the chamber door.

3

Pump the chamber.

4

On the Detectors tab, select BSD from the drop down list.

5

Open the Panel Configuration bar.

6

Double-click BSD Contr ol .

The BSD Contro l panel allows you to change the polarity of the segments, select BSD modes and set the BSD gain.

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7

Set the mode of the quadrants: a

4-segment BSD

Click a quadrant symbol to change its status: normal (+), inverted (-) or disabled.

b

To select compositional mode, click BSD: COMPO.

c

To select topography mode, click BSD: TOPO.

8

Select the BSD Gain from the drop-down list. Low, Medium, High, Very High .

5-segment BSD


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BSD Imaging with Stage Biasing

Stage biasing (beam deceleration) is a method used for decelerating the electron beam’s landing energy by applying a negative potential to a specimen. The lower landing energy of the primary electrons provides the possibility to obtain more specimen surface detail especially at low magnifications. Better image resolutions can also be obtained at high magnifications.

Beam deceleration is generally used when imaging specimens with BSE detectors. The stage bias functionality can only be applied in the high vacuum mode in the range of 0 to -5 kV. The effectiveness of the stage biasing and beam deceleration will solely depend on the specimen type. Imaging improvements can easily be achieved when using metallic specimen; more surface detail will be revealed.

Landing energy is the difference between the energy of the primary beam electrons and the bias applied to the stage. If the EHT voltage is set to 5kV and a stage bias potential of -4kV is applied, the landing energy would be 1kV.

The beam deceleration option can also be used for applying low voltages on specimens in the range of +20V to -20V. The SE detector is normally used in combination with low voltage specimen biasing. Although, the low specimen biasing effects are subtle, an improvement in the image contrast can easily be seen. The low voltage specimen biasing can be applied under the HV and VP conditions.

The beam deceleration kit is mounted through a plate on the stage door. A specially designed 9 stub specimen holder is generally used when imaging specimen with the stage biasing functionality. This is to isolate the specimen holder, i.e. the bias is only applied to the specimen.

1

2

3

The beam deceleration kit is mounted on the stage door ( 1) The 9-stub carousel sample holder used for stage biasing ( 1,2 )

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The HDBSD images below show the effect of applying a bias to an aluminium fracture specimen. The images are taken at 5 kV accelerating voltage, in HV and at a working distance of 8.5 mm. 1

2

Fig. 6.1: Al fracture su rface imaged at 0 V bias ( 1). Al fracture surface imaged at -4400 V bias (2).

When the stage bias is 0 volts the landing energy of the electron beam is 5 kV. The landing energy of the electrons is decelerated to 600 V as the stage bias of – 4400 V is applied. More morphological information is revealed as the landing energy of the electron beam is reduced.

IMPORTANT If the Beam deceleration carousel checkbox is activated, then the Stage bias low voltage option is not available, but the beam deceleration option is available. Despite sharing the same electronics, low voltage and high voltage are mutually exclusive. Low voltage demands the beam deceleration carousel is removed (the carousel is a special sample holder designed to withstand the high voltage and also improve the imaging). High voltage demands the beam deceleration carousel is fitted. The user tells the system this via the checkbox. This checkbox is used to enforce rules.


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Using Beam deceleration

Preconditions:

• • •

Stage has been initialised before fitting the beam deceleration carousel HV mode is active Beam deceleration carousel is fitted

Procedure: 1

From the Panel Configuration bar, select Stage Navigation .

The Stage Navigation dialog opens. 2

From the Sample Holder drop-down list, select Carousel 9x9mm.

3

Make sure that the Safe Navigation checkbox is activated.

4

From the Panel Configuration bar, select Variable Stage Bias . The Variable Stage Bias dialog opens.

5

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Activate the Beam deceleration carousel checkbox.



6

Activate the Beam deceleration checkbox. This enables adjustments of the Beam deceleration volts slider.This enables the stage

bias functionality as long as all the preconditions are met. The messages „Stage bias HV is ON“ and „Warning: Touch alarm not enabled“ will be displayed. 7

Adjust the voltage with the slider until you are satisfied with the result.

Using stage bias low voltage

IMPORTANT LV Biasing can work with any standard, conducting, dovetail mounted carousel; it will not work with lens mounted sample holders and other non-dovetail mountings.

Preconditions:

• • •

Stage has been initialised HV mode is active Standard conducting dovetail-mounted sample holder fitted

Procedure: 1

From the Panel Configuration bar, select Stage Navigation . The Stage Navigation dialog opens.

2

From the Sample Holder drop-down list, select the installed sample holder.

3

Make sure that the Safe Navigation checkbox is activated.

4

From the Panel Configuration bar, select Variable Stage Bias . The Variable Stage Bias dialog opens.


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5

Activate the Beam deceleration carousel checkbox. This enables the stage bias functionality as long as all the preconditions are met.

6

Activate the Stage bias low volt age checkbox. This enables adjustments of the Stage bias Low Volts slider.

CAUTION Risk of stage collision If you choose a voltage between -5 V and +5 V, a warning is displayed saying that touch alarm is disabled. In this voltage range, the touch alarm becomes unreliable and there is a risk of stage collision going undetected. Always move the bias voltage to a larger value before moving the stage.

7

Adjust the voltage with the slider until you are satisfied with the result.

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6.5.4.4. Other optional detectors There are several other optional detectors. They can be used as follows:

• • • •

VPSE: Change to Variable Pressure mode as described in section 6.5.3.2. EPSE: Change to Extended Pressure mode as described in section 6.5.3.3. CL : Select the detector in High Vacuum mode as described in section 6.5.4.1. STEM: Select the High Vacuum mode or Variable Pressure mode as described in section 6.5.3.1. or section 6.5.3.2.


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6.5.5. Imaging wet specim ens with the Pelti er cools tage A Peltier cooling stage and an Extended Pressure (EP) EVO system is required for imaging hydrated specimens. This will enable to study hydrated specimen in their native state with little or no loss of water in the SEM (the sample is kept fully hydrated during the pump down).

6.5.5.1. Fitting the Peltier coolstage 1

If required, retract all retractable detectors. Vent the chamber. Remove the lens mounted BSD (if fitted) and place it in the parked position.

2

Unscrew the currently fitted aperture if fitted.

3

Select the 100 µm EP upper aperture and the 500 µm lower aperture/ BeamSleeve ®.

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4

Using the red aperture insertion tool insert the 100 µm upper aperture in the final lens. This should be finger tight only.

5

Using the black aperture insertion tool insert the 500 µm lower aperture. This should be finger tight only. The O-ring may give some slight resistance which is normal.


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6

Select the Ap ert ur es tab and click Select Apertur e.

7

Select the EP aperture, the panel will then expand.

8

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Select the 500µm Beam Sleeve®.



9

Remove the round right hand blanking plate from the stage door using an Allen key SW 3.


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10 Detach the Peltier-Coolstage assembly from its holder plate by undoing the cable ties.

11 Feed the Peltier-Coolstage holder through the hole in the stage door and carefully rest it with its pipe work on the stage.

12 Attach the Peltier head to the stage via the dovetail fitting used for all other sample holder types.

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13 To ensure the Peltier cable is not too bent, twisted or strained it will be necessary to ad just the stage using stage rotation to a suitable position.

14 Attach the Peltier-Coolstage holder to the SEM stage using an Allen key SW 2.5.

15 Fix the Peltier vacuum flange to the stage door using an Allen key SW 3.


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16 Place the plain stub onto the Peltier-Coolstage sample holder using the stub tool. Ensure that the stub is positioned horizontally (is not tilted) for obtaining good contact to the cooling area. Maintaining a constant cooling temperature on the stub is essential for wet imaging of hydrated samples.

17 Carefully tighten the clamp screw using an Allen key SW 1.5.

18 Re-fit the BSD if required. 19 Carefully close the chamber door without trapping the pipe work of the peltier coolstage.

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20 Switch on the Peltier Coolstage Coolstage power power supply. supply.

21 Sele Select ct the the Gun Vacuum tab. 22 Click Pump . 23 Wa Wait it un unti till Vac Status = Ready and EHT Vac ready = Yes are indicated.

This can take some time.

24 Se Sellect Stage/Navigation from the menu bar.


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25 Se Sellect CoolStage MK3 from the drop-down menu.

If it is not in the list: a

Sele Select ct Set Setti ting ngs/ s/Sho Show w Ga Gall ller ery. y.

b

Select CoolStage MK3 from the catalogue.

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c

Tick the Is Available checkbox.

CAUTION Risk of damaging the Peltier stage pipe by using stage rotation. Only move the stage in X and Y.

26 Se Sellect Tools/Administrator and and log in with your username and password. Peltier Fitted checkbox. 27 Se Sellect Other and and tick the Peltier

28 Select the USB USB connectio connection n and tick the Humidity Option checkbox.


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29 Sele Select ct the the Vacuum tab and select Go to EP. 30 Set EP Targe Targett tto o 10 Pa.

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6.5.5.2. Purg ing the c hamber 1

From the Panel Configuration bar, select Extended Pressure.

The Extended Pressur e window opens. 2

Tick the Peltier checkbox

3

Click Purge Settings .... Check that EP Gas = Ai r is selected.

The aim of purging is to remove air from the water bottle and to fill the chamber with just water vapour.


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How to continue

Procedure 1

•

If the water kit has recently been fitted, filled with water, or has not been used for a while, continue with procedure 1.

•

If the system has recently been used in the wet mode, continue with procedure 2.

1

Set Purge cycles to 10.

2

Set Purge Max to 1000 Pa.

3

Set Purge Min to 10 Pa.

4

Click EP Gas = A ir . This will then change the vacuum status to EP Gas = Water Vapour.

5

Click Manual Purg e H2O to start purging.

The pressure in the chamber will vary between the previously set max and min levels. Bubbles may be seen in the water bottle. All air is eventually removed from the water bottle. This will take a while to be completed.

The progress is shown in the status bar.

Continue with obtaining an image in EP mode (see section 6.5.5.3.).

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Procedure 2

1

Set Purge cycles to 7.

2

Set Purge Max to 1000 Pa.

3

Set Purge Min to 10 Pa.

4

Click EP Gas = Ai r . This will then change the vacuum status to EP Gas = Water Vapour.

5

Click Manual Purg e H2O to start purging.

The pressure in the chamber will vary between the previously set max and min levels. Bubbles can be seen in the water bottle. All air is eventually removed from the water bottle. This will take a while to be completed.

The progress is shown in the status bar.

Continue with obtaining an image in EP mode (see section 6.5.5.3.).


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6.5.5.3. Obtaining an image in EP mode 1

In the Extended Pressure window set the Peltier Target to 1 °C and suitably adjust the Humidity Target.

2

Adjusting the position of the green cross on the phase diagram will change the environment of the sample; water vapour, water, or ice.

3

Switch on the beam and start imaging.

4

Use the chamberscope and stage navigation for positioning the specimen under the beam.

6.5.5.4. Setting SEM parameters for imaging the specimen in wet mode The SEM operating parameters depend on the type of specimen being examined and the nature of the detail you are expecting to see. It is recommended to start with:

• • • •

EHT = 20 kV

1

Image a distinguishable feature under the beam.

2

Increase the pressure to 550 Pa keeping the temperature constant at 1 °C.

I Probe = 400 pA or higher WD = 6.0 mm Detector = BSD or EPSE

Increase the pressure in steps of 20 Pa and review the image. The water droplets start to appear around 600 Pa. 3

Once the water droplets are clearly visible on the stub make a note of the pressure. The rate of water condensation from the chamber on the stub and the evaporation of the droplets from the stub to the chamber should be at equilibrium.

4

Enter the pressure value obtained in the previous step as Purge Min in the Purge Control window.

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5

Select a pressure around 100 Pa higher than the Purge Min value and enter that as Purge Max value. The Purge Cycle can now be changed to 3.

6

Vent the chamber without changing any of the parameters.

7

Remove the plain stub and dry the area underneath the stub on the Peltier coolstage. Carefully mount the specimen on a new stub, place and tighten the stub on the Peltier coolstage.

8

Use a pipette for putting a few droplets of distilled water on the Peltier coolstage holder.

IMPORTANT Do not put any water droplets on the stub or directl y on the specimen as the water droplets can cover the specimen surface and prevent viewing the areas of interest. 9

Move the Peltier coolstage slightly to the right or left of the chamber before closing the chamber door. This will prevent any droplets splattering up on the EPSE, BSD or the final lens area during the pump down process.

10 Close the chamber door and pump down the system. 11 Run up the gun and move the sample under the beam using chamberscope and/or image navigation panel. 12 Start imaging in wet mode; if necessary increase the pressure but in very small steps. If necessary, adjust the humidity level values to achieve 100% humidity. But the latter will change both the Peltier temperature and the chamber pressure. 13 Increasing the pressure in large steps results in accumulation of water on the specimen and prevents the imaging. Be ready to experiment with your parameters:

• • •

Increased EHT increases the signal strength but might damage the specimen Decreased spot size provides higher resolution but means loss of signal Reduced WD increases the signal strength however, a montage of specimen images might be required as the field of view will become smaller at reduced WD.


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6. Operation Using the help functions

6.6. Using th e help fu nct ion s The SmartSEM® user interface offers a multitude of help texts containing information on the operation of the SEM, the optimization of the images and the handling of accessory options.

6.6.1. Calli ng t he SmartSEM® help 1

Press . Alternatively, select Help/SmartSEM help from the menu.

The SmartSEM® help start window opens. If menus are opened in the SmartSEM ® user interface, pressing < F1> will open the help text for the respective menu. This allows explaining the menu while the SEM is being operated.

6.6.1.1. Prin tin g help t exts 1

Click the printer icon in the help window.

If a printer is installed, the help text is printed.

6.6.1.2. Bringing help texts to t he foreground 1

Select Help/Help Always On Top from the menu.

The displayed help texts remain in the foreground.

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6.6.2. Calling the con text-sensiti ve help 1

Press . Alternatively, select Help/What’s This from the menu.

The mouse cursor is equipped with a question mark. 2

Move the cursor to the area of interest on the screen.

3

Left-click with the mouse.

The help text is shown. 4

To disable the context-sensitive help, press .

6.6.3. Search ing for a topi c 1

Select Help/Search from the menu.

2

Click the Search tab.

3

Search for the desired topic.


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6.6.4. Usin g t he step-by-step guid es The step-by-step guides provide quick information on important operation sequences.

6.6.4.1. Getting start ed 1

Select Help/Getting started from the menu.

2

Click the topic of interest.

6.6.4.2. Frequentl y used o peration sequences

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1

Select Help/How To from the menu.

2

Click the topic of interest.



6.6.5. Calli ng th e short cuts help Many functions and menus which are often used in the SmartSEM ® user interface can also be opened using the keyboard. A list of short cuts (key combinations) can be displayed in the SmartSEM® help. 1

Press < F9>. Alternatively, select Help/Keys help from the menu.


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6.6.6. Showing inf orm ation abou t SmartSEM® 6.6.6.1. Version his tor y The Release Notes summarise important information about the software version history. New functions, bug fixes and special features of the different versions are explained. 1

Select Help/Release Notes from the menu.

6.6.6.2. About SmartSEM® 1

Select Help/Abou t SmartSEM from the menu.

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6. Operation Finishing the work session

6.7. Finishi ng th e wor k session To finish your work session, switch off the EHT: a

Click the Al l: button in the status bar.

b

Select EHT Off from the pop-up menu.

6.7.1. Tungsten Emitter It is recommended that when using a Tungsten filament the gun is turned off when the system is not being used for any significant period of time.

6.7.2. LaB6 Emit ter It is recommended that when using a LaB6 filament that the gun is not turned off during its service life time. To obtain the maximum life time of a LaB6 emitter the EHT must be switched off when not in use and for long periods of time the gun should be switched to STANDBY. The service life time can be further extended by Long Fil Life in the Gun tab of the SEM Contro ls panel. This will reduce the filament current to „First peak“ conditions which will give satisfactory operating conditions for general microscopy. If optimum performance is required the Long Fil. Life checkbox should be unticked.


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6. Operation Closing the SmartSEM® user interface

6.8. Closi ng t he SmartSEM® user int erface 6.8.1. Logging off 1

Select File/Log Off from the menu.

A window appears asking for confirmation to close the session.

2

Confirm by clicking on the Yes button.

The electron-optical parameters are filed in a macro in the individual user directory.

The EM Server remains active.

6.8.2. Exiting 1

Select File/Exit from the menu.

A window appears asking for confirmation to close the session. 2



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6. Operation Switching off the SEM as a matter of routine

6.9. Switchi ng o ff t he SEM as a matter o f ro uti ne 6.9.1. Changing t o STANDBY mode Change to STANDBY mode when the SEM is not operated, even for longer periods. The filament will continue to be heated, and the vacuum in electron optical column and specimen chamber will be maintained.

STANDBY mode is also the recommended mode to store the SEM. In this case, tick the Partial Vent on Standby checkbox in the Vacuum tab of the SEM Contro ls panel. This can help to prevent oil vapours from penetrating into the specimen chamber during the period of storage.

1

Switch off the EHT.

2

Close SmartSEM®: a


The SmartSEM® Close UIF window appears asking for confirmation to close the session. b


The electron-optical parameters are filed in a macro in the individual user directory. 3

Shut down the PC.

4

Press the STANDBY push button.

The yellow STANDBY button lights up.


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6. Operation Switching off the SEM as a matter of routine

6.9.2. Changing t o OFF mod e 1

Switch off the EHT.

2

Switch off the gun.

3

Close SmartSEM®: a


A window appears asking for confirmation to close the session. b



4

Shut down the PC.

5

Press the OFF push button.

The red OFF button lights up.

Computer, electronic components and vacuum system are switched off. The electron optical column is partially vented. A 24 V auxiliary voltage is still present to restart the SEM.

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6. Operation Switching off in an emergency

6.10. Swit chin g of f i n an emergency 1

Push down the circuit breakers at the back of the plinth.

6.10.1. Switchi ng o n again after an emergency o ff IMPORTANT Before switching on the SEM, ensure that the reason for the emergency off does not exist any more and that it is safe to switch on the SEM.

1

Push up the circuit breakers at the back of the plinth.


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6. Operation Switching off the SEM completely

6.11. Switchi ng off the SEM compl etely This procedure completely cuts off the SEM from the electrical main supply. 1

Switch off the EHT.

2

Switch off the gun.

3

Close SmartSEM® a


The SmartSEM® Close UIF window appears asking for confirmation to close the session b



4

Shut down the computer.

5

Press the yellow STANDBY button. The yellow STANDBY button lights up.

6

Press the red OFF button. The red OFF button lights up.

7

Close and lock the main shut-off valves at the installation site.

8

Switch off the SEM at the isolation switch at the back of the unit.

9

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Isolate from the main electrical supply.




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7. Maintenance and repair

7. Maint enance and r epair WARNING Magnetic fields can interfere with medical implants. Ion getter pumps generate a magnetic field that can i nterfere with medical implants, such as cardiac pacemakers. The magnetic field is also present if the SEM is switched off. When performing any maintenance tasks at the column, such as replacing filaments, it is possible to get close to the ion getter pumps and their magnetic field. If you have a medical implant fitted, always keep a safety distance of ≥ 10 cm to the ion getter pumps.

CAUTION Risk of injury. Risk of property damage. Perform only such tasks described in this instruction manual. All pursuing tasks of maintenance, service, and repair not described in this instruction manual have to be performed by authorised ZEISS service representatives.

IMPORTANT To maintain best possible performance of the SEM it is essential to perform preventive maintenance on a regular basis. Moreover, it is recommended that you obtain a service contract with your local ZEISS service organisation or representative. This will ensure a continuous trouble-free operation of the SEM.

Scheduled downtime is the time when the SEM is not available to perform its intended function due to planned downtime events.

• • •

Change of consumables and chemicals Basic preventive maintenance performed by the operator Preventive maintenance performed by authorised ZEISS service representatives


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7. Maintenance and repair Change of Consumables and Chemicals

7.1. Change of Consumables and Chemicals The change of consumables and chemicals is a scheduled interruption of operation to replenish process consumables and chemicals. The times scheduled are designed to maximise equipment performance level (i.e. 24 h of permanent operation).

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Interval

Component/Part

Action

as required

Filament

Replace the filament as described in section 7.1.3.

Yearly or as required

Pre-vacuum pump

Replace the tip seal. Refer to pump manufacturer’s documentation.

Yearly

ETSE detector BSD

Contact the local ZEISS service representative in order to have the detectors checked and scintillators replaced if required.



7.1.1. Adjusting the isolation mounts The isolation mounts lose air over time. Therefore it is necessary to adjust them from time to time.

CAUTION Crushing hazard. The gap between isolated table and plinth is designed to allow the specimen chamber to swing freely. The size of the gap varies during operation and can cause crushing injuries. Do not place your fingers between isolated table and plinth.

1

To check if the air feet need to be adjusted, give the column a gentle nudge. - If it is unable to move freely, adjust the air feet as described in the following steps. - If the column is able to move freely, no further action is required.

There are three inlet valves at the back of the plinth. Each of the inlet valves corresponds to a different section of the levelling system. 2

To adjust the air feet, remove the caps from the inlet valves at the back of the plinth.

3

Attach a foot pump to one the inlet valves.

4

Pump the inlet valve so that the corresponding air foot has a flat top (refer to images for details).

5

Repeat steps 3 and 4 for the remaining inlet valves.

6

Ensure that the gap is consistent around the isolated table.

7

Check that the column is able to move freely. If not, repeat steps 3 to 7 until the column is able to move freely.


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7.1.2. Replacing t he tip seal of the pr e-vacuum pump Refer to the instruction manual of the pre-vacuum pump provided by the pump manufacturer. You will find this documentation in the SEM document folder.

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7.1. 7.1.3. 3. Replacin Replacin g fil aments Possible reasons:

•

Filament has come to the end of its normal service life

IMPORTANT You can display the operating hours of the fi lament by selecting View/SEM Status/ Select/Filament Select/Filament Age. The Filament Age will be displayed in the t he Display tab.

1

8

2

7

6

3

4

5

1

Lint-free gloves

5

Allen key SW 1.5 x 3

2

Cotton wool

6

Filament tool

3

Toothpick

7

Metal polishing compound

4

Twee Tweeze zers rs for for fil filam amen entt-re remov moval al o orr insertion

8

Can Can of of co comp mpre ress ssed ed air air

Fig. 7.1: 7.1: Overview Overview of required too ls


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7.1.3.1. Replacing pre-aligned tungsten filaments CAUTION Risk of contamination. contamination. Dust particles and skin grease can cause bad vacuum and flashovers. Always wear gloves gloves when changing the the filament.

Parts/ rts/sp spe ecia cial tools tools re require quired d

part part no. no.

Pack of 10 pre-centred tungsten filament cartridges (stainless steel)

354720-9919-000

IMPORTANT Where a column interlock is fitted as described described section 2.4.1.2. the 2.4.1.2. the requirement to fully switch off the SEM is removed. The firing unit change is the same process for machines with and without the column interlock, however however the image below shows how the interlock is separated when the column lid is opened and care must be taken when closing the gun to ensure the interlock is correctly lined up when the gun is closed.

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1

Shutdown Gun.

2

Select the Gun Vacuum tab.

3

Click Vent Gun .

The Vent Gun dialogue is displayed. 4

Click Yes and allow system to fully vent before carrying out further steps in the procedure.


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Tick the New Filament checkbox.

5

Vent Vent the the spe speci cime men n cha chamb mber er..

6

Swit Switch ch off the the SEM SEM as as des descr crib ibed ed iin n section 6.11.

7

Remo Remov ve tthe he top top cov cover er..

CAUTION Burning hazard The EO column gets hot during operation. After switching switching off the SEM, wait for fifteen minutes before opening opening the the top section section of of the EO column.

8

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Wait the the firing firing unit unit to to coo cooll down down for at leas leastt fiftee fifteen n min minute utes. s.



9

Open the gun.

10 Unscrew the firing unit with an Allen key SW 1.5 (3 screws). The screws should remain in their holes if possible.


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11 Carefully remove the firing unit.

12 Put the firing unit on a clean surface. 13 Fit the filament tool into the slots in the brass retaining washer.

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14 To unscrew unscrew the the brass retaining retaining washer, washer, carefully turn the filament tool anticlockwise.

15 Remove the brass retaining retaining washer. washer.

16 Put the brass retaini retaining ng washer washer on a clean clean surface. 17 Put your your hand closely closely underneath underneath the firing firing unit and turn it upside down. The filament holder and the tensator spring washer will slide out and drop into your hand.

IMPORTANT The tensator spring washer is not designed for pre-aligned filaments. If the tensator spring washer is installed with a pre-aligned filament, the height of the filament will be wrong. Do not reinstall the tensator t ensator spring washer washer when installing a pre-aligned filament. filament.


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18 Remove the tungsten tungsten d deposit eposits s as describ described ed in section 7.2.7.

IMPORTANT The tungsten filament deposits tungsten on the firing unit over time. These deposits have to be removed after every filament exchange. ZEISS encourages customers to keep a record on filament changes. This simplifies maintenance. 19 Take a new pre-alig pre-aligned ned filament filament holder holder from from the box.

20 Use the the can o off compressed compressed air to remove any dust particles from the filament holder and the firing unit.

21 Align Align the slot slot at at the side side of the the filament holder (1 (1) with the pin inside the firing unit (2 (2 ). ).

1

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2



22 Put the new filament filament into the the firing firing unit. unit.

23 Reinstall Reinstall the the brass retaini retaining ng washer washer and fix fix it with the filament tool.

24 Ensure the brass brass retaining retaining washer is secure. secure. If it makes any sound when shaking it, tighten the brass retaining washer a bit more.


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25 Align the the slot slot at the the side of the firing unit (1 (1) with the pin inside the firing unit holder (2 ( 2 ). ).

1

2 26 Careful Carefully ly push push in the firing firing unit unit.. 27 Fix the screw with an Allen Allen key SW 1.5.

28 Check Check the the colum column n O-ring O-ring (3).

3

29 Remove any dust dust particles particles with a can of compressed air.

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30 Close the gun.

31 Reinstall the top cover.

32 Switch on the SEM as described in section 6.1.


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7.1.3.2. Replacing tungsten filaments (not pre-aligned) - cleaning, maintenance & alignment This section describes how to replace regular tungsten filaments. These filaments are not prealigned.

CAUTION Risk of contamination. Dust particles and skin grease can cause bad vacuum and flashovers. Always wear gloves when changing the filament.

Parts/special tools required

part no.

Pack of 10 tungsten filaments

350010-2079-000

IMPORTANT Where a column interlock is fitted as described section 2.4.1.2. the requirement to fully switch off the SEM is removed. The firing unit change is the same process for machines with and without the column interlock, however the image below shows how the interlock is separated when the column lid is opened and care must be taken when closing the gun to ensure the interlock is correctly lined up when the gun is closed.

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1

Remove firing unit from SEM as described in section 7.1.3.1.

2

Put the firing unit on a clean surface.

3

Fit the filament tool into the slots in the brass retaining washer.

4

To unscrew the brass retaining washer, carefully turn the filament tool anticlockwise.

5

Remove the brass retaining washer.


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6

Put the brass retaining washer on a clean surface.

7

Put your hand closely underneath the firing unit and turn it upside down.

The filament holder and the tensator spring washer will slide out and drop into your hand.

8

Disassemble the filament holder: a

Unscrew the four screws with an Allen key SW 1.5. These screws have rounded ends.

b

Remove the top section of the filament holder.

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c

Unscrew the four grub screws at the top section of the filament holder. These screws have pointed ends.

d

Remove the filament with the filament tool.

e

Put all parts of the filament holder on a clean surface.

If the filament holder shows tungsten deposits, remove the deposits as described in section 7.2.7.

IMPORTANT The tungsten filament deposits tungsten on the filament holder over time. These deposits have to be removed after every fifth filament exchange. This also applies to the anode (refer to section 7.2.7.2. ). ZEISS encourages customers to keep a record on filament changes. This simplifies maintenance.


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9

Take a new filament out of the box using the filament tool.

10 Insert the new filament in the top section of the filament holder using the filament tool.

11 Insert the four grub screws. 12 To centre the filament, equally screw all grub screws with an Allen key SW 1.5. These screws have pointed ends.

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13 Attach the top section of the filament holder to the top section. Pay attention to correct alignment of pin and hole.

14 Insert the tensator spring (1) into the firing unit.

1

15 Insert the filament holder. Pay attention to correct alignment of pin and slot. Align the slot at the side of the filament holder (2 ) with the pin inside the firing unit (3).

3

2

16 Put the new filament into the firing unit.

Turns o f brass retaining washer

Filament distance (mm)

Comments

¾

0.4

High Resolution. Short Filament Life Time

1¼

0.6

General Use. Extended Filament Life

1¾

0.9

X-Ray Analysis

Table 7.1: Setting the filament distance by turning the brass retaining washer


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17 Reinstall the brass retaining washer and fix it using the filament tool. Choose the amount of turns according to table 7.1.

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18 Check that the filament is centred and flush with the top of the firing unit using a stereo light microscope. If the filament is not centred, a

centre the filament by turning the grub screws. These screws have pointed ends.

If the filament is not flush with the top of the firing unit, a

adjust the height of the filament by turning the brass retaining washer.


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19 Align the slot at the side of the firing unit (1) with the pin inside the firing unit holder (2 ).

1

2

20 Carefully push in the firing unit. 21 Fix the screw with an Allen key SW 1.5.

22 Check the column O-ring (1).

1

23 Remove any dust particles with a can of compressed air.

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24 Close the gun.




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7.1.3.3. Replacin g L aB6 fil aments CAUTION Risk of contamination. Dust particles and skin grease can cause bad vacuum and flashovers. Always wear gloves when changing the filament.


part no.

One LaB6 filament

350010-2180-000


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1

Remove firing unit from SEM as described in section 7.1.3.1.

2

Put the firing unit on a clean surface.

3

Fit the filament tool into the slots in the brass retaining washer.

4

To unscrew the brass retaining washer, carefully turn the filament tool anticlockwise.

5

Remove the brass retaining washer.

6

Put the brass retaining washer on a clean surface.


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7

Put your hand closely underneath the firing unit and turn it upside down.

The filament holder and the tensator spring washer will slide out and drop into your hand.

8

Disassemble the filament holder: a


b


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c


d


e



IMPORTANT The LaB6 filament deposits sublimed material on the filament holder over time. These deposits have to be removed after every filament exchange. ZEISS encourages customers to keep a record on filament changes. This simplifies maintenance. 9

Unpack the new LaB6 filament. a

Unscrew the plastic cover.

b

Press in the metalic pin to unlock the filament.


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c

Use the filament tweezers to remove the new LaB6 filament from the holder.





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1




2

3


17 Reinstall the brass retaining washer and fix it using the filament tool.

IMPORTANT Accurate centring and height adjustment are essential to ensure optimum performance and maximum service life.


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18 The LaB6 filament needs to be set 0.2 mm below the Wehnelt cap. This is achieved by ad justing the filament height level to the top of the Wehnelt aperture by turning the retaining brass washer slowly clockwise and checking both height and centring with a microscope or hand lens.

19 Once the filament is flush with the top of the Wehnelt cap, the brass retaining washer should be turned 20 degrees anti-clockwise. The filament tip is now approximately 0.2 mm below the top of the Wehnelt cap. 20 Centre the filament with the grub screws. These screws have pointed ends.

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1

2



1



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26 Close the gun.



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29 Select the Gun Vacuum tab. 30 Click Pump . 31 Wait until Vac Status = Ready and EHT Vac ready = Yes are indicated.

This can take some time.


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32 Make sure the Long Fil. Life checkbox is unticked. 33 Switch on the beam. 34 Set the following values: - EHT = 10 kV - Spot Size = 500 - Fil I Target = 1950 mA 35 Tick the New Filament checkbox .

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36 Select the Ap ert ur es tab. 37 Click Emission .

The Emission button changes to Normal .


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IMPORTANT The filament runup will take a while for the first few times when a new filament is installed. This is quite normal and is designed to minimise damage due to thermal shock when the filament is new. 38 Slowly increase Fil I Target by 0.01 A increments by clicking the right hand arrow of the Fil I Target slider until the first emission peak

is visible . Adjust Brightness and contrast levels to aid visualisation.

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39 Continue to increase Fil I Target until the second (and final) emission peak is visible. Adjust Brightness and contrast levels to aid visualisation.

IMPORTANT To achieve optimum performance, the emission image must be aligned to the centre on the image area. This is achieved by using Beam Tilt and Beam Shift on the Apertures tab.

Beam not aligned

40 Select the Ap ert ur es tab. 41 Click Normal to allow SEM imaging.


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7.1.3.4. Replacing LaB6 filaments with tungsten filaments CAUTION Risk of contamination. Dust particles and skin grease can cause bad vacuum and flashovers. Always wear gloves when changing the filament.


part no.

EVO-W-FIRINGUNIT: One tungsten wehnelt assembly with a box of ten W standard filaments

350071-2832-000

IMPORTANT Tungsten and LaB6 firing units are not compatible with each other.

IMPORTANT It is not possible to install a LaB6 firing unit on an instrument built for Tungsten. This can only be achieved by carrying out an instrument upgrade which requires return of the unit to the factory. THIS UPGRADE PROCEDURE IS NOT POSSIBLE AT CUSTOMER LOCATION.


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1

Shutdown Gun.

2

Select the Gun Vacuum tab.

3

Click Vent Gun .

The Vent Gun dialogue is displayed. 4

Click Yes and allow system to fully vent before carrying out further steps in the procedure.


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5

While the system is vented, select the filament type from drop down menu.

6

Tick the New Filament checkbox.

7

Switch off the SEM as described in section 6.11.

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CAUTION Burning hazard The gun at the top of the EO column gets hot during operation. After switching off the SEM, wait for fifteen minutes before opening the top section of the EO column.

8

Wait the firing unit to cool down for at least fifteen minutes.

9

Open the gun.


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10 Unscrew the firing unit with an Allen key SW 1.5 (3 screws). The screws should remain in their holes if possible.

11 Put the firing unit on a clean surface. 12 Fit the filament tool into the slots in the brass retaining washer.

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13 To unscrew the brass retaining washer, carefully turn the filament tool anticlockwise.

14 Remove the brass retaining washer.

15 Put the brass retaining washer on a clean surface. 16 Put your hand closely underneath the firing unit and turn it upside down. The filament holder and the tensator spring washer will slide out and drop into your hand.


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17 Disassemble the filament holder: a


b


c


d


e



IMPORTANT The tungsten filament deposits tungsten on the filament holder over time. These deposits have to be removed after every filament exchange. This also applies to the anode (refer to section 7.2.7.2. ). ZEISS encourages customers to keep a record on filament changes. This simplifies maintenance.

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18 Take a new filament out of the box using the filament tool.




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1


3

2


Turns of brass retaining washer

Filament distance (mm)

Comments

¾

0.375

High Resolution. Short Filament Life Time

1¼

0.6

General Use. Extended Filament Life

1¾

0.9

X-Ray Analysis

Table 7.2: Setting the filament distance by turning the brass retaining washer

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26 Reinstall the brass retaining washer and fix it using the filament tool. Choose the amount of turns according to table 7.1.


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27 Check that the filament is centred and flush with the top of the firing unit using a stereo light microscope. If the filament is not centred, a

Centre the filament by turning the grub screws. These screws have pointed ends.

If the filament is not flush with the top of the firing unit, a

adjust the height of the filament by turning the brass retaining washer. Choose the amount of turns according to table 7.1.

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1

2



1



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33 Close the gun.



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36 Select the Gun Vacuum tab. 37 Click Pump . 38 Wait until Vac Status = Ready and EHT Vac ready = Yes are indicated.

This can take some time. If the gun vacuum is lower than 1 x 10 -8 mbar, perform the bakeout procedure as described in section 7.2.5.

39 Make sure the Long Fil. Life checkbox is unticked. 40 Switch on the beam.


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41 Set the following values: - EHT = 10 kV - Spot Size = 500 - Fil I Target = 2000 mA

42 Select the Ap ert ur es tab. 43 Click Emission .

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The Emission button changes to Normal .

IMPORTANT The filament runup will take a while for the first few times when a new filament is installed.


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44 Slowly increase Fil I Target by 0.01 A increments by clicking the right hand arrow of the Fil I Target slider until the first emission peak

is visible . Adjust Brightness and contrast levels to aid visualisation.

45 Continue to increase Fil I Target until the second (and final) emission peak is visible. Adjust Brightness and contrast levels to aid visualisation.

IMPORTANT To achieve optimum performance, the emission image must be aligned to the centre on the image area. This is achieved by using Beam Tilt and Beam Shift on the Apertures tab.

Beam not aligned

46 Select the Ap ert ur es tab. 47 Click Normal to allow SEM imaging.

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7. Maintenance and repair Basic preventive maintenance performed by the operator

7.2. Basic pr eventiv e maint enance perfor med by t he operator 7.2.1. Checking for safe operation Check that all protective covers are in place. Inspect and clean the product safety labels to maintain good legibility.

7.2.2. Cleaning up the PC As with any PC it is important to periodically clean up the PC. 1

Empty the temporary files folder.

2

Defragment the hard drive.

3

Check for adequate free space on the hard drive.

7.2.3. Init ialisi ng t he stage If a stored stage position cannot be approached or if absolute stage movement is required, the stage needs to be initialised. Executing this function requires the Stage initialise privilege in the user profile. Prerequisites:

• Specimen chamber has been vented. • All large specimens and large specimen holders are removed. Procedure: 1

Select Stage/Stage initialis e from the menu.

2

Confirm by clicking on Yes .

IMPORTANT If initialisation of the stage does not solve the stage problem, contact your local ZEISS service representative.


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7.2.4. Servici ng t he pre-vacuum pu mp For maintenance of the pre-vacuum pump refer to the instruction manual of the pump provided by the pump manufacturer. You will find this documentation in the SEM document folder.

7.2.5. Baking out the gun and the ch amber For optimum use of the LaB6 filament it is essential that the gun vacuum is always in the 10 -7 mbar region (10 -8 mbar for EVO®HD). If the vacuum falls below this value it is strongly recommended that the gun chamber bakeout procedure is carried out which would typically be an overnight procedure.

IMPORTANT In order to maintain peak operating condition, it is recommended to perform a weekend bakeout at least twice a year.

1

Select Al l/Sh ut do wn Gun from the status bar in order to switch off EHT and gun.

2

Wait until the gun has ramped down.

3

From the menu bar, select Tools/Goto Panel . The Panel Configuration bar opens.

4

Double-click Bakeout .

The Bakeout dialogue is shown. 5

Select Bakeout = Overnigh t from the drop down list.

6

Click Bakeout Start .

CAUTION Risk of injury from hot surfaces during bakeout Parts of the enclosure in the upper range of the column may become hot during bakeout, particularly after a long bakeout cycle. Do not touch any parts of the cover panel or place any combustible objects on the electron optical column.

7

Allow the column to cool down. The pressure will be changing due to residual heat retain in the gun area and a cooling period is necessary to allow the vacuum to improve. The cooling period depends on the room temperature. The gun monitor will monitor the pressure improvement as the cooling time progresses and reached the pressure 10 -7 mbar region (10 -8 mbar for EVO®HD).

8

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Switch on the gun to continue working with the microscope.



7.2.6. O-ring maintenance O-rings are necessary to keep up the vacuum and protect the column and the chamber from dust particles and grease. The column and chamber door O-rings have to be checked and cleaned regularly. Possible reasons:

• •

Regular maintenance Bad vacuum

CAUTION Risk of damaging the O-rings. O-rings can be damaged when treated with any solvents such as acetone or alcohol. Do not use any solvents to clean the O-rings.

7.2.6.1. Checki ng t he Column O-ring 1

Open the gun as described in section 7.1.3.1.

2

Check visually if there are any dust particles or grease on the O-ring.

3

Use a can of compressed air to remove any dust particles or grease.

4

If any dust particles or grease remain, use a lens tissue to remove the dust particles or grease.

5

Close the gun as described in section 7.1.3.1.

IMPORTANT Grease on O-rings can attract dust causing it to build up on the vacuum seal which can lead to vacuum leaks. Some greases can migrate into the vacuum chamber leading to poor vacuum and contamination of samples, detectors and other SEM components. Do not apply grease to O-rings.


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7.2.6.2. Checking the chamber door O-ring CAUTION Suffocation hazard due to lack of oxygen, since the specimen chamber is vented with nitrogen. Avoid inhaling the air from within the specimen chamber. Ensure the area around the SEM is sufficiently ventilated.

IMPORTANT Contamination caused by fingerprints can lead to vacuum deterioration or prolonged pumping times. Always wear lint-free gloves when touching specimen, specimen holder or stage. Keep the chamber door open as short as possible.

Procedure: 1

Vent the specimen chamber.

2

Open the chamber door.

CAUTION Danger of damaging the sealing surface when using metallic tools. If required, use a plastic or wooden tool to remove the chamber door O-ring.

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3

Check visually if there are any dust particles or grease on the O-ring (1).

1

4

Use a can of compressed air to remove any dust particles or grease.

5

If any dust particles or grease remain, use a lens tissue to remove the dust particles or grease.

6

Close the chamber door.

7



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7.2.7. Cleaning the fir ing u nit

CAUTION Risk of damaging the aperture. The filament deposits material on the firing unit and the anode over time. This can damage the aperture and reduce the filament life time. Clean the firing unit after every filament change.

1

Remove the firing unit as described in section 7.1.3.1.

2

Put the smallest amount possible of Wenol silicon-free polishing compound on a piece of printing paper.

3

Polish the top of the firing unit in a circulating movement.

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4

Wrap a piece of cotton around the tip of a toothpick.

5

To remove any deposits, polish the inside of the firing unit.

6

Use the toothpick to clean the aperture of the firing unit. Remove any discolouration.

7

Turn the firing unit upside down and use the toothpick to clean the other side of the aperture.

8

Rinse the parts contaminated with polish with warm water containing a few drops of mild detergent.


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CAUTION Risk of property damage. Residual polishing compound can cause flashovers and bad vacuum. To remove residual polishing compound, grease and other hydro carbon contaminates it is essential to clean all the firing unit parts using a weak solvent such as isopropanol (propan–2–ol CAS No–67–63–5).

9

Put the firing unit and the brass retaining washer in a metal mesh tray.

10 To remove residual polishing compound, put the metal mesh tray in a beaker of isopropanol in an ultrasonic bath. Repeat this two times with clean amounts of isopropanol.

11 Reinstall the firing unit as described in section 7.1.3.1.

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7.2.7.1. Cleaning t he fil ament ho lder 1

Disassemble the filament holder as described in section 7.1.3.2.

2

Place the disassembled filament holder parts (including all grub screws) and all screws in a suitable metal mesh tray.

3

To remove residual polishing compound, put the metal mesh tray in a beaker of isopropanol in an ultrasonic bath. Repeat this two times with clean amounts of isopropanol.

4

Reassemble the filament holder as described in section 7.1.3.2.


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7.2.7.2. Cleanin g t he Ano de For optimum performance this procedure should be carried out each time a filament is changed. To reduce instrument down time it is recommended that a clean spare anode is purchased so that the dirty anode can be cleaned off line. 1

Vent and open the gun chamber as detailed in section 7.1.3.1. for tungsten and section 7.1.3.3. for LaB6 systems.

2

Locate and unscrew retaining screws using an Allen key SW 3. Do not remove the screws as they will be removed with the anode later.

3

Using long reach flexible tweezers carefully remove anode along with retaining screws.

4

Unless a clean anode is immediately available for fitting close the gun lid to prevent ingress of dust.

Used anode showing accumulation of emitter vapour deposits

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5

Place a small amount of polish on a clean piece of paper and polish as shown.

6

To clean the anode aperture use a cocktail stick with the polish ensuring both sides of the aperture are cleaned.

7

Remove the excess polish with warm water containing a few drops of mild detergent and then place the anode and the retaining screws in suitably sized metal mesh tray.

8

Further clean the anode by placing the tray containing the anode and the retaining screws in an ultrasonic bath as described in section 7.2.7.2.


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IMPORTANT Contamination caused by fingerprints can lead to vacuum deterioration or prolonged pumping times. Always wear lint-free gloves when touching the cleaned anode and retaining screws. 9

Remove all parts from the cleaning solvent and allow to dry. It is essential that the anode and retaining screws are handled using clean lint free gloves from this point of the procedure.

Cleaned anode

10 Refitting the anode is the reverse of the removal procedure shown in steps 2 and 3.

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7. Maintenance and repair Preventive maintenance performed by a ZEISS service representative

7.3. Preventive maintenance performed by a ZEISS service representative Preventive maintenance is a scheduled downtime essential to achieve the maximum equipment performance level (i.e. 24 h of permanent operation).

The annual preventive maintenance is performed by the local ZEISS service representative. It includes

• • • •

Inspection Preventive actions Equipment test Verification run


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7. Maintenance and repair Repair

7.4. Repair The repair tasks described in the following section can be performed by the operator.

IMPORTANT All pursuing tasks of repair not described in this instruction manual have to be performed by authorised ZEISS service representatives only.

7.4.1. Replacing the ch amber doo r O-ring Possible reasons:

•

Chamber door does not close tightly, bad chamber vacuum

CAUTION Suffocation hazard due to lack of oxygen, since the specimen chamber is vented with nitrogen. Avoid inhaling the air from within the specimen chamber. Ensure the area around the SEM is sufficiently ventilated.

IMPORTANT Contamination caused by fingerprints can lead to vacuum deterioration or prolonged pumping times. Always wear lint-free gloves when touching specimen, specimen holder or stage. Keep the chamber door open as short as possible.

Procedure:

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1

Vent the specimen chamber.

2

Open the chamber door.



CAUTION Danger of damaging the sealing surface when using metallic tools. If required, use a plastic or wooden tool to remove the chamber door O-ring.

3

Clean the O-ring as described in section 7.2.6.2.

If this does not resolve the problem: a

Remove the chamber door O-ring (1).

1

a

Insert the chamber door O-ring.

b

Close the chamber door.

c



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7.4.2. Checking the ci rcui t br eakers Possible reasons:

•

Circuit breaker is tripped (lower position)

Procedure: 1

2

Check the circuit breakers at the back of the plinth.

No.

Value

Circuit

F1

10 A

Power supply unit

F2

10 A

PC, WDX, EDX, AUX 1 -4

If one of the circuit breakers is tripped, push upwards.

If this does not solve the problem, contact your local ZEISS service representative for assistance.

IMPORTANT Tripped circuit breakers may be a hint for an electrical problem in the SEM. If a circuit breaker is tripping again, switch off the SEM completely and contact the ZEISS service for assistance.

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8. Troubleshooting

8. Troublesho otin g The following table gives some clues to solve problems. If you cannot solve the problem or if you are feeling unsure do not hesitate to get in contact with your local ZEISS service representative.

DANGER Danger to life: Hazardous voltage inside the SEM. Only service engineers trained and authorised by ZEISS are allowed to service the SEM and to perform work on the electrical system of the SEM.

Keyword

Symptom

Possible reason

Recommended action/s

SEM

SEM does not operate.

Circuit breaker is tripped (lower position).

Check the circuit breakers. Refer to section 7.4.2.

Vacuum

„Vac ready = OK“ is not shown after specimen exchange.

System vacuum is bad due to a vacuum leak at the chamber door.

Check the chamber door seal for cleanliness. If required, replace the chamber door seal.

„Vac ready = OK“ is shown very late after specimen exchange.

Gas ballast at rotary pump or scroll pump is activated.

Deactivate gas ballast at the prevacuum pump.

Vacuum

SEM does not vent.

No nitrogen.

Check nitrogen supply. Check compressed air supply.

System vacuum

„Vac ready = OK“ is indicated abnormally fast.

Penning gauge has not been identified correctly.

Restart the SEM: If this does not solve the problem, call your local ZEISS service representative.

System vacuum

Bad system vacuum.

Chamber door seal does not seal tightly.

Replace the chamber door seal. Refer to section 7.4.1.

Specimen stage

Stage does not move.

Stage needs to be initialised.

Initialise the stage. Refer to section 7.2.3. If this does not solve the problem, call your local ZEISS service representative.

Specimen stage

Stored position cannot be approached correctly.

Stage needs to be driven to a well-defined position.

Initialise the stage. Refer to section 7.2.3.

Specimen stage/ PC

Stored position cannot be approached correctly.

PC has crashed. Stage needs to be driven to a well-defined position.

Restart the PC Initialise the stage. Refer to section 7.2.3.


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8. Troubleshooting

Keyword

Symptom

Possible reason

Recommended action/s

Drift

Specimen seems to be moving.

Charging effects. Non-conducting specimen.

Ensure proper conduction of the specimen. Optimise specimen preparation. Apply a charge compensation method.

Image quality

Image is bad at low EHT (e.g.1 kV)

Working distance is too long.

Reduce working distance to a maximum of 7 mm.

SE2 image

SE2 image is noisy

Scintillator is used up.

Call your local ZEISS service engineer to have the scintillator replaced.

After emergency off or power failure

Stored stage position cannot be approached correctly.

Stage needs to be initialised.

Initialise the stage. Refer to section 7.2.3.

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9. Shutdown and disposal Putting the SEM out of operation

9. Shutdow n and disp osal 9.1. Putting the SEM out o f op eratio n If the SEM will not be used for an extended period of time e.g. several months, it should be put out of operation.

Contact your local ZEISS service representative to have the SEM put out of operation.

9.2. Disposal 9.2.1. Disposing of solid waste (consumables) The operator must ensure that solid waste (consumables) are disposed of and recycled in a responsible manner.

Description

Material

Disposal

Apertures

Platinum, iridium, gold

Very small amounts. May be disposed of in accordance with local/regional regulations.

Rotary Pump

Oil

Customer to dispose of in accordance to local/regional regulations.


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9. Shutdown and disposal Disposal

9.2.2. Dispo sing of the SEM The operator must ensure that waste products are disposed of and recycled in a responsible manner. Refer to EC directive 2002/96/EC on waste electrical and electronic equipment (WEEE). The SEM consists of several modules. Be careful to separate the materials properly when you dispose of the SEM.

• •

Materials: e.g. metals, non-metals, composite materials, process materials Electronic scrap material: e.g. transformers, circuit boards, cables

Comply with national and regional waste disposal ordinances.

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10. Parts and tools Important consumables

10. Parts and too ls CAUTION Risk of injury or property damage when using inappropriate parts or tools. Use genuine ZEISS parts only. Order parts and tools at your local ZEISS service organization.

For customer service please contact your local ZEISS service representative. A list of ZEISS locations and authorised service partners can be found at: www.zeiss.de/microscopy

10.1. Import ant c onsu mables Item

Part no.

Aperture (single hole)

348520-0229-000

Anode aperture, 70 µm (40 nA high resolution configuration)

348520-0612-000

Anode aperture, 110 µm (100 nA high current configuration)

348520-0610-000

Anode aperture, 200 µm (300 nA high current configuration)

348520-0589-000

Extractor aperture

348520-0097-001

Anode aluminum seal

348520-0609-000

Copper seal gun head (single use)

340002-0382-000

Tip seal for pre-vacuum pump BOC Edwards XDS 10

113-898

Scintillator for SE2 and HE-SE detector

348306-8142-000


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10. Parts and tools Important spare parts

10.2. Import ant s pare parts Item

Part no.

Chamber door o-ring

476-960

10.3. Option al so ftw are licences Item

Part no.

FISHEYE mode

348224-6080-000

10.4. Tools and accessories

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Item

Part no.

Faraday cup

348342-8055-000

1.5 mm Allen wrench

151-883

Small pliers

-

specimen holders

Refer to specimen holder catalogue.

Stubs

-

Tweezers

-

Gloves, lint-free

-


11. Abbreviations

11. Abbr eviation s AIC

Ampere interrupting capacity

BSE

Backscattered electron

CCD

Charge coupled device

DPA

Differential Pumping Aperture

EC

European community

EHT

Extra High Tension

EIGA

European Industrial Gases Association

EMC

Electromagnetic compatibility

EMO

Emergency off

GUI

Graphical User Interface

H

Height

ETSE

Everhart Thornley Secondary Electron Detector

IGP

Ion Getter Pump

M

M-axis

MSDS

Material Safety Data Sheet

PC

Personal computer

PE

Protective Earth

R

R-axis

SE

Secondary Electron

SEM

Scanning Electron Microscope

T

T-axis

U

Voltage

UIF

User Interface

W

Width

WD

Working distance

WEEE

Waste Electrical and Electronic Equipment


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11. Abbreviations

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X

X-axis

Y

Y-axis

Z

Z-axis

ZTR

Z-Tilt-Rotate


12. Glossary

12. Glossary

Aperture

Small opening in the beam path that forms and limits the electron or ion beam.

Astigmatism

Lens aberration that distorts the shape of the electron beam, compensated by the stigmator.

Backscattered Electrons

High energy electrons that are liberated from the specimen surface when the specimen is hit by the primary electron beam.

Bakeout

Degassing of surfaces of a vacuum system by heating during the pumping process.

Condenser

Device that collects and focuses the electron beam onto the specimen.

Depth of field

Distance along the optical axis which an object in the specimen can be moved while remaining in focus

Faraday cup

Small Insulated metal container, equipped with an aperture where electron can enter but not escape. Used to measure the specimen current in the SEM.

Focus wobble

Function that sweeps the focus of the objective lens backwards and forward through the focus on the specimen plane. When the aperture is misaligned a lateral shift is observed.

Optibeam

The Optibeam program takes the requirements for probe current, working distance, etc. and determines the optimum lens settings to achieve the best performance from the column. Optibeam operates in several different Modes that can be selected on the SEM Control Apertures tab. Some Optibeam modes are not available when the fixed aperture is fitted

Penning gauge

Device for measuring high vacuum in the vacuum system.

Pre-vacuum pump

A pump for generating a pre-vacuum.

Primary electrons

Narrowly focused beam of accelerated electrons that hit the specimen surface.

Scintillator

Substance that absorbs electrons and in response, fluoresces photons while releasing the previously absorbed energy.

Secondary electrons

Low energy electrons that are liberated from the specimen surface when the specimen is hit by the primary electron beam. Secondary electrons are generated by inelastic scattering.

Stigmator

Compensates astigmatism (lens aberration), so that the electron beam becomes rotationally symmetrical.


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12. Glossary

X-ray

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Type of ionising radiation that is generated during the operation of electron microscopes


13. Declaration of conformity

13. Declaration of co nformit y

Denomination:

Scanning electron microscope (SEM)

Model:

EVO®

Manufacturer

ZEISS Ltd . 511 Coldhams Lane Cambrid ge CB1 3JS UK

This is to declare that the machinery mentioned above fulfils all the relevant provisions of the

•

Directive 2006/42/EC.

Moreover, the machinery fulfils the following directives and standards:

• • • • • •

Directive 2004/108/EC Standard EN 60204-1 Standard EN 61000-6-4 Standard EN 61000-6-2 Standard EN 61010-1 Standard EN ISO 12100-1/2

Unauthorised modifications of the machinery will cancel this declaration.

CE markin g

The CE conformity marking is located on the type plate of the machinery.


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13. Declaration of conformity

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14. Index

14. Index A Abbreviations 237 Acceleration voltage 39 Administrator 13 Analysis mode 41 Anode 39 Apertures 39 Auomated image acquisition 99 Auto aperture alignment 93 Auto gun alignment 92 Auto saturation 91 Automated functions 91 B Bakeout 216, 239 Beam deceleration 126 C Chamber door interlock 21 Chamber door seal 228 Charging 232 Chemicals 159 Compressed air 231 Conformity 241 Consumables 159, 235 Control panel, optional 29 Conventions, typographical 11 Cover panels 20 Customer service 62 D Declaration 241 Detectors 43 Disposal 233 Documents, related 9 Dose rate 15 Downtime 159 Drift 232 Drift correction 94 Dual joystick 28 E EHT 39 Emergency off 154, 232 Evacuating 31 F Faraday cup 119, 239 Field mode 41 Filament 39 Fisheye (column mode) 42 Fisheye mode 42


Fuses 230 G Gas ballast 231 Gun vacuum 31 H Help 146 High leakage current 16 I Image navigation 98 Initialise stage 215 Installation 65 Intended use 13 Interlocks 20 K Keyboard 29 L Location requirements 60 M Main shut-off valves 21 Maintenance overview 159 Material Safety Data Sheet 24 N Nitrogen 16, 231 O Operating modes 41 Operation, safe 215 Operator 12 Operator training 13 Operator, advanced 12 Operator, basic 12, 13 P Penning gauge 231, 239 Power failure 232 Preventive maintenance 159, 215, 227 R Radiation 14, 15 Radiation protection 14 Resolution mode 42 S Safety 10, 13, 14 Safety devices 20

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14. Index

Safety instruction 10 Safety labels 21, 215 Sample type selection 96 Scintillator 160, 239 Seismic protection 21 Service 14 Shutdown 233 SmartSEM® 12 Software 27 Software Manual 9 Solid waste 233 Spare parts 236 Specimen chamber 25 Specimen stage 38 Stage bias low voltage 127 Stage biasing 124 Start-up 65 Storage 64 Switching off 156 System vacuum 30, 231 T Terms 12 Tip seal 160, 162 Tools 236 Transport 63 Troubleshooting 231 U User 12 User interface 27 V Vacuum 231 Vacuum leaks 18 Vacuum system 30 Ventilating 31 Voltage, hazardous 14 W WEEE 234 X X-rays 15

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14. Index


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Instruction Manual EVO

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