zeiss sigma vp feg sem manual

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Zeiss Sigma VP FEG SEM Quick start Guide

Compiled by Greg Baty, Rick Hugo, Matthew Hughes

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The manufacturer’s manuals for CEMN’s Zeiss Sigma VP SEM and installed accessories total well over 1,000 pages as of September 2014. Oxford Instruments Aztec software is still in development. WDS, “Feature” and some specialty applications will be added to complete the suite. As this happens we expect manufacturers manuals will continue to grow, even if we do not add more accessories in the future. Due to the volume of information it is not practical to use the manufacturer’s manuals during training. Typically only a small percentage of the information is useful to a given user.

This quick start guide is intended as a training aid and reference for common problems. It is not a comprehensive manual or replacement for proper training. If you have questions or are not sure of a procedure, please ask a member of the CEMN staff for assistance.

Designated CEMN staff members provide instrument training to new users of the lab. Upon successful completion of training, users that demonstrate safe operation of the instruments may be certified as independent users by the instrument manager. All users of CEMN are required to review the lab rules and return the agreement to follow the rules to the instrument manager. Certification / continued certification are at the discretion of the instrument manager.

Under special circumstances (e.g. university classes, manufacturers training representatives, etc.) the instrument manager may authorize a non staff member to act as trainer. Users that conduct training without authorization of the instrument manager will have their user privileges revoked and be liable for any damages.

If you do not want to be an independent user of CEMN but need to use our resources, staff may be available to operate the instruments for you.

If your samples are considered hazardous materials, you are required to have approval to bring them to CEMN. Our staff and contractors need to know what hazards are present so we can comply with safety regulations.

For some light reading you might enjoy:

Scanning Electron Microscopy and X-‐Ray Microanalysis, Goldstein, Newbury, et al.

Electron Backscatter Diffraction in Materials Science, Schwartz, Kumar, et al.

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Anatomy of our UI and Chamber

EDS Detector ET Secondary electron detector

Objective lens VP Detector

Sample stage (9x9)

Retractable BSD not shown normally located here when inserted

Gun and Vacuum status indicator

EBSD detector shown in the inserted position

Super Secret Side bar

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The basic operations table below is used as a general operating procedure. Start at the top and work toward the bottom.

Keyword Item Recommended Actions

Initial inspection when entering instrument room

Pumps operating Notify instrument manager if pump is not running

Open or missing covers on instrument

Do not use, contact instrument manager

Power indicator on If indicator is not on contact instrument manager

Unusual sounds or smells Notify instrument manager, possible safety issue

Purge gas Open valve, Normal pressure is 1 – 2 psig

Maximum pressure is 3psig

Notify manager if tank pressure is < 200 psig

Log into instrument Log into FOM Activate reservation

Log into SmartSEM Double click the SmartSEM icon and

enter your login credentials

Verify Vacuum and electron gun status

If status indicators are not green do not use instrument, contact instrument manager

Venting the chamber Turn on CCD Push Camera button on operator control panel

Do any detectors need retracted

Move EBSD and BSD to safe position. If EBSD is inserted venting may cause damage.

Is the stage in a safe condition

Move stage to safe position, if needed

Close WDS gate valve Usually closed, use INCA to close gate if open

Verify EHT is off The EHT status should be a red X Select Vac icon then vent Follow on screen prompts

Listen for purge gas If not flowing open valve Gently open door when chamber is at atmospheric pressure

Close Nitrogen valve if the system will be at atmosphere > 1 minute Slamming the door may result in misalignment of the door or stage

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Keyword Item Recommended Actions

Load Sample Select appropriate stage adaptor

Install stage adaptor if needed

Secure sample to stage Use appropriate tools and supplies. The

standard holder uses a 1.5mm Allen

Select proper sample holder in stage navigation window

Observe maximum stage loading, 500g tilted, 1kg untilted

Pump the chamber Turn on CCD Push Camera button on operator control panel if CCD is off

Make sure specimen current monitor is not active

Super secret side bar, Specimen Current Monitor, uncheck the box

Make sure there is clearance between sample and lens / detectors

Visual inspection and CCD use

Gently close the door Stop if there is unusual resistance

Slamming the door may result in misalignment of the door or stage

Select VP or High Vacuum Super secret side bar, VP control

Select Vacuum status icon then pump

Turn on purge gas if it is off Open Nitrogen valve

Set operating parameters

Select operating conditions See list of starting recipes and set appropriate parameters

Insert BSD if need Use CCD to make sure the BSD has

sufficient clearance

Lift silver lock on BSD actuator and gently insert the detector

It is possible to run the stage into the left side of the retraction arm. Be careful since this is out of CCD view

Set / estimated initial working distance

Select View menu, crosshair

Use CCD and Joystick to set estimated working distance

The bottom of the pip at the center of the screen is ~8mm WD

No closer than the diameter of a number 2 pencil

Wait until vacuum status is ready

green check mark on the status icon

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Keyword Item Recommended Actions Optimize beam Turn EHT on Click EHT status icon, EHT on

Select aperture Use the aperture tab

Set electron acceleration Double click EHT on the data bar and type in a value

Select an appropriate electron detector

See list of recipes, Double click Signal A on the data bar

Adjust Brightness and Contrast

Use knobs on control panel

Focus the image Use the focus knob on the operator control panel

Optimize stigmators look for stretching when focusing

Align the aperture Use the wobbler and adjust premature x y knobs to minimize wobble

Adjust working distance to desired value

Use the CCD and Joystick

Select electron detector Reoptimize focus and stigmator

Take images Appropriately pose the sample

use joystick

Optimize Brightness and Contrast

Use the Brightness and contrast knobs

Using the line scan feature in the scanning tab can be helpful

Auto Brightness and Contrast is located in the scanning tab (not recommended during image save)

Select an image size Scanning tab, store resolution 1024x768

is recommended Set scan speed and noise

reduction Scanning tab

Usually speed 4 to 8

Line average N=4

Freeze on end of frame

Freeze the image Press the freeze button on the console

Save image <Ctrl+e> or use menu file save image

Select the file directory and naming convention

Unfreeze the image Press the freeze button on the console

If scanning is not restored click the normal icon

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Keyword Item Recommended Actions Operating non Zeiss accessories

Activate Remcon Usually there is an icon for Oxford or and Icon for NPGS If the Icon is missing contact the instrument manager to have your account reconfigured

Operate the accessory Refer to the accessory manual Shutdown Vent chamber Follow the vent chamber procedure Pump Chamber Follow the pump chamber procedure

Go to high vacuum mode Super secret side bar, VP control

Wait for vacuum status ready

Vacuum status icon is green

Close the column chamber isolation valve

Super secret side bar, airlock, close column chamber isolation valve

Log out of SmartSEM Exit

Log out of FOM Complete reservation

Turn purge gas off Turn of nitrogen tank valve

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Random but important bits of information • Magnification is the ratio of “viewed image width” / “scanned image width”. There are two

magnification references available to users. Most users are configured for “output device” (monitor). However, it is possible to set Polaroid 545 as a magnification reference.

o If you are using NPGS you need to set the magnification reference to Polaroid 545 or you will have unexpected results.

o When you print your digital images magnification is likely inaccurate or useless. Many users just leave the magnification value as is, since that is how the image was viewed. The printed scale bar is accurate, as long as you maintain the image aspect ratio.

• People like to measure things in SEM. Generally measurements are accurate to about ±3%. However, you should make sure and understand the pixel size at the magnification you are using. The best you can measure is ± 1 pixel; however, statistical Measurement System Analysis will likely tell you the result is worse. We occasionally see people that are measuring with to few pixels and trying to infer a change in measurement.

o You must have an accurate focus to get accurate measurements. The calculation of pixel size is based on working distance. Using lens hysteresis removal <Shift+F2> may improve results.

o The most accurate measurements are generally at a close working distance with settings that give a low depth of focus.

• Most parameters listed the data zone can be changed by double clicking with the mouse. E.g. to change detectors double click the signal and select from the list.

• When Specimen Current Monitor (SCM) or Specimen Current Detectors (SCD) are active the sample touch alarm is disabled. Oxford Aztec and INCA software automatically turn on SCM when they open. Make sure and turn SCM off since this is a global setting (it effects all users)

• VP mode is a global feature. Please make sure and go to High Vac. Mode at the end of your session. It is hard on the vacuum system to have long periods of VP.

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CHOOSING AN IMAGING DETECTOR, ADJUSTING B&C

Under the SEM Control Panel, select the “Detectors” tab Choose the desired detector from the drop-‐down menus. Alternatively you could use the data zone to change signal A. Detectors SE is useful for topographic imaging in high vacuum mode at working distances >4mm. Typical detector bias is ~300 -‐ 350V for SE imaging; however, adjusting bias can help optimize image quality. Using a negative bias value will cause the detector to reject SE resulting in a poor mans back scatter image. Typical starting acceleration is 5kV, with a working range of 1 – 30kV. In VP mode the detector bias is disabled to prevent arcing. VPSE is the default variable pressure detector. Image information is similar to SE, but areas of the sample with higher charge levels will be brighter. Typically start with a detector bias of 85%, 40pa N2, Acceleration ≥ 15kV, 60µm aperture in high current mode. Acceleration from 8 – 30kV can be useful. Working distance is typically 5 – 15mm. Pressure in the range of 10 – 80pa is typically useful. In high vacuum mode some samples with have a CL signal that can be used to understand variations in elemental distribution that can not be seen in BSD or EDS.

NTS BSD is a retractable five diode BSD used for qualitative compositional imaging in high vacuum or VP mode. The primary contrast mechanism is Z contrast. Areas of the sample with heavier elements appear brighter. Typical starting parameters: acceleration 15kV, 60µ aperture in high current mode, with the 4 center diodes set to +. Useful working range of ~7 – 30kV, 30µ -‐ 120µ aperture.

• Shadow mode is given by all 5 elements marked “+” • Compo mode is given by all 4 annular segments marked “+” • Topo mode is given by one hemisphere marked “+”, and the other

marked “-‐“

Select a BSD gain appropriate for your beam current. You should start with “high” gain since it works well for most samples. If your detector contrast needs to be set above 90% for proper contrast, increase the gain level. If the detector contrast needs to be set below 10%, reduce the gain level

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In Lens SE detector is a high resolution secondary electron detector that reduces the percentage of SE2 and SE3 signals observed. Below about 1000x magnification, there will be significant detector artifacts. The detector is top down looking so you loose shadow contrast making the sample look flatter than it is. However, resolution is improved due to the reduction of SE2 and SE3 signals. Operation is restricted to high vacuum mode and accelerations ≤ 20kV. Typical parameters are 5kV with a 30µm aperture and a WD of 3 – 5mm. Acceleration of .2 – 20kV is possible. Working distance is limited by acceleration but 3 – 10mm can be useful. SCD is used to generate an image of transmitted current. This detector requires use of the SCD control found in the super secret sidebar. Generally you need a gain of very high. This detector is not useful for most specimens. When this detector is active, sample touch alarm is disabled. CCD is used to observe the chamber when moving the stage or closing the door. Adjusting brightness and contrast (BC) can be accomplished in many ways on our Sigma. The preferred method of most users is the Brightness and Contrast knobs on the control panel. However, under the scanning tab it is possible to set Auto-‐brightness and contrast. This feature tends to be annoying since it is continuously trying to optimize BC, but it is useful to get a starting point. Set “Auto BC = Off” once you have a starting point. The line scan feature found on the scanning tab can be a useful feature to aid optimization of BC.

ACCELERATING VOLTAGE

Accelerating voltage can be set under SEM control panel – “Gun” tab To set the EHT:

1) Double-‐click “EHT target” text 2) Enter the desired voltage

Alternatively you can double click EHT on the data zone and enter the desired value. It will take several seconds for the EHT to ramp. In some cases if you change an EHT value, the EHT will ramp to 0 then ramp to the set value. Zeiss refers to accelerating voltage as EHT or “electronic high tension” EHT values from .2kV to 30kV are valid. Lower values give more surface information, but you will have vignetting if the working distance is too long. In VP mode higher values improve image characteristics since there is less scattering of the beam due to gas interactions.

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WORKING DISTANCE

Working distance is adjusted under Stage Navigation panel The Working Distance (WD) is the effective focal point, not a physical location. To safely set the working distance, the operator controls Z (the distance between the gun lens and the bottom of the chamber). WD is measured from focus value (final lens current). To set a desired WD: 1) Focus the sample accurately 2) Note current WD 3) ΔZ = current WD – desired WD 4) Under the “Stage Navigation” panel, click Z button 5) Within the pop-‐up text entry field, enter the calculated ΔZ 6) Switch to CCD/”TV” view, and observe chamber on monitor

a) If current WD = 8mm, lower WD (positive ΔZ) in 1mm increments b) If current WD = 5mm, lower WD (positive ΔZ) in 0.1mm increments

7) Switch back to sample view and refocus the sample to confirm WD

NOISE & CHARGE REDUCTION

Basic noise reduction modes: • Scan speed – balance S/N with charging and acquisition time

o Higher number is slower (note cycle time) • Line average

o Repeats the line N times at the given scan speed • Frame average (good for charge reduction at low mag)

o Repeats the whole image N times at the given scan speed • Note: “Avg” mode cycles continuously; “Int” mode completes just one frame and blanks beam • You usually want to set freeze on end of frame so you do not end up with scan artifacts in your saved image • Generally Scan 4 – 8 with line average N=4 is a good starting place • If you have charging, try a faster scan speed with lots of frame averaging or frame integration.

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ZEISS ANALYTICAL TIPS

From Rick Hugo’s Analytical imaging tips (Zeiss microscope controls) 1) For BSE imaging only, set EHT to > 10kV, Apt > 30micrometers, high current mode. Higher EHT will

result in noticeable edges effects (I.e. Use 10kV for specimens with many phases boundaries and/or cracks)

2) For BSE imaging and "typical" EDS analysis, EHT > 15kV, Apt 60micrometers, high current mode 3) Load extra control windows

a) (Hidden sidebar -‐ "BSD control", optional "image Navigation") 4) Insert back scatter detector and controls

a) Toggle on TV Camera (macros -‐ TV) and visually check the specimen clearance b) Insert detector -‐ lift retaining knob, guide rod in slowly c) Select BSD (SEM control tabs -‐ detectors -‐ signal A = CZ BSD) d) Adjust BSD gain and BSD element configuration

i) Larger aperture/high current mode will require lower BSD gain ii) Compo mode -‐ 4 annular elements "+" iii) Differential TOPO mode -‐ 1 side of annulus "+", opposite side of annulus "-‐" iv) For both compositional and topographic information, set all 5 elements "+"

e) Note: regardless of noise reduction mode BSE images must be acquired with scan rate > 7 5) To navigate from a saved image (SEM, light microscope, flatbed scan, camera image, etc…):

a) Make sure scan rotation is off (rotate scan rotation knob; if image rotates, press knob down to deactivate)

b) Load control panel (Hidden sidebar – “Image Navigation”) c) Load saved image with ‘external image’ button d) To register the image, click “setup” and follow instructions. Use “CPoint” macro to center

specimen features. 3-‐point registration is recommended.

Random INCA tips 6) If doing WDX, you must open the gate valve while pumping the system down!

a) Open INCA before pumping down b) In Energy mode, select “Options -‐> Energy + options -‐> Display status bar” c) Gate valve can be controlled by right-‐clicking status bar

7) After setting up imaging parameters as above, enable communication with INCA computer (“Oxford” or “INCA” macro)

8) Save Quant Optimization specimen, faraday cup, and other “repeating” locations in stage points list 9) INCA quirks:

a) If you desire good quant from Smart Maps, you must quant optimize before mapping i) Start in Analyzer mode ii) In “Acquire” function, select “spectrum conditions” tab and select desired conditions iii) Quant Optimize on correct element

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COMMONLY USED HOT-KEYS

Generally, it is more productive to use hot keys so you can keep your hands on the control panel. Many users reject use of hot keys, and prefer to use menus. The table below is a lost of commonly used hot keys.

Hot Key Action

Tab Switch between course/fine adjustments

Ctrl + Tab Center image (to cancel, simply right-‐click mouse)

Ctrl + Shift + Tab Select region of interest (ROI) to image (centering/magnification to ROI)

Ctrl + e: Save image (opens save dialog to select save folder, enter sample ID, and set indices)

F4 Cycles forward through magnification table

Shift + F4 Cycles backward through magnification table

Shift + F2 Lens hysteresis removal

Ctrl + F Auto focus (not recommended, but it works on some samples)

Ctrl + S Auto Stigmator (not recommended, but it works on some samples)

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Rick Hugo’s cheat sheet

Zeiss-specific recipes – startingconditions for conductive specimens(high vacuum mode)Information required Suggested working conditions

(HC = high current mode)

Detector EHT Apt /HC WD

Basic topographic imaging SE2 10-‐20kV 30µmNo HC

10mm

High resolution imaging InLens 20kV 30µmNo HC

5 mm

Fine surface details InLens SE2

2kV 30µmNo HC

5 mm

beam sensitive specimen SE2 2kV 20µmNo HC

5mm

Maximum depth of field SE2 10-‐20kV for high-‐Z spec

2-‐5kV for low-‐Z

10µmHC on

10mm for hi-‐kV6mm for low kV

Compositional contrast imaging, conductive spec

CZ BSD, 4 segments active

10-‐20 kV 60µmHC on

~8.5mm

Surface topography with composition information



10mm

Trace element variations CL detector (VPSE)


10mm

EDS quant (INCA settings: process 3, 0-‐10 keV, 2k channels, EDS detector slide out as nec for 40-‐60% DT)

EDS 20kV 60µmHC on

8.5 mm

X-‐ray mapping (INCA settings: process 2-‐3, 0-‐10 keV, 1k channels, EDS detector slide out as nec for 60% DT)

CZ-‐BSD and EDS 20kV 120µmHC on

8.5 mm

WDS/EDS quant (INCA settings: process 3, 0-‐10keV, 2k channels, WD gate valve open, EDS out as nec for 40-‐60% DT)

CZ-‐BSD, EDS and WDS

20kV 120µmHC on

8.5 mm

Low-‐kV EDS/WDS (INCA settings: process 5, 0-‐10keV, 2k channels, WD gate valve open, EDS out as nec for 40-‐60% DT)

CZ-‐BSD, EDS and WDS


8.5 mm

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Zeiss-specific recipes – startingconditions for non-conductivespecimensInformation required Suggested working conditions

(HC = high current mode, HV = high vacuum mode, VP = variable pressure mode)

Detector Vacuum mode

EHT Apt /HC WD

Basic topographic imaging VPSE orCZ BSD, 5

segments

VPP = 40 Pa

20kV 60µmHC on

15mm

High(er) resolution, VP mode VPSE VPP = 20

20kV 30µmHC on

8 mm

Fine surface details SE2 HV 2kV 30µmNo HC

5 mm

Beam sensitive specimen SE2 HV 2kV 20µmNo HC

5mm

Maximum depth of field -‐ VP mode VPSE VPP= 40

20kV 30µmHC on

15mm

Compositional contrast imaging CZ BSD, 4 segments active

VPP = 40

20 kV 60µmHC on

~8.5mm

Surface topography with composition information


VPP=40

20 kV 60µmHC on

10 -‐ 15mm

EDS quant (INCA settings: process 5, 0-‐20 keV, 2k channels, EDS detector slide out as nec for 40-‐60% DT)Note: no WDX operation in VP mode!

EDS VPP = 40

20kV 60µmHC on

8.5 mm

X-‐ray mapping (INCA settings: process 2, 0-‐10 keV, 1k channels, EDS detector slide out as nec for 60% DT)

CZ-‐BSD and EDS

VPP=40

20kV 120µmHC on

8.5 mm

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TROUBLESHOOTING

1) No electron image a) Make sure a valid electron detector is

selected in signal A b) If BSD is selected

i) Make sure the detector is inserted ii) Increase detector gain iii) Make sure the four center diodes are

active (+ icon) c) Select lowest magnification -‐ check

brightness/contrast; WD (focus point) should be >0.

d) Make sure beam is scanning -‐ select "Normal" macro

e) Check that EHT is ON f) Check beam blanker box (between SEM

console and table) to see if beam is blanked by NPGS program. If so, i) Switch the far right monitors input to

DVI ii) Use the right most keyboard and

mouse to operate the NPGS computer iii) Double-‐click 'NPGS' icon if the program

is not running iv) Select 'SEM mode' (you may need to

select SEM mode 2-‐3x) g) Call CEMN staff for help

2) Sample touch alarm a) Immediately notify CEMN staff there is a

sample touch alarm 3) EDS, count rate low or high

a) Optimize working distance 8.5mm b) Fully insert EDS spectrometer c) Set process time

i) Point and ID or analyzer mode process 3 – 6 depending on application

ii) Mapping process 1 -‐ 3 d) If counts and dead time are low increase

aperture or decrease process time e) If counts or dead time are high decrease

aperture, use a faster process time or partially withdraw EDS

If the center status light of the beam blanker is active, most likely NPGS has beam control

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zeiss sigma vp feg sem manual