User Guide to Operating the Zeiss Sigma 500VP SEM

Nanoscale Fabrication and Characterization Facility, Petersen Institute of NaoScience and

Engineering, University of Pittsburgh, 348 Benedum Hall, 3700 O’Hara Street, Pittsburgh, PA 15261

Sample Preparation

Put on a pair of gloves. Samples should be clean, as small as possible, stable in vacuum. If needed,

clean samples, stubs and the specimen holder with isopropanol and kimwipe papers.

Mount fragment or powder samples firmly on Al-stubs using C-tape. Fix stubs onto the ZEISS

specimen holder. 9 stubs may be loaded. Mount thin sections directly on the specimen holder.

Make maps if necessary to be used to locate each sample in the SEM.

Warning Salt and oils from fingerprints will contaminate the FESEM vacuum and your samples if you

do not wear gloves. Fingerprints can be removed with isopropanol and kimwipe.

Starting ZEISS SmartSEM Program

First, the tool needs to be activated by logging onto the Zeiss SEM in FOM system.

The EM Server, implementing the internal communication between software and hardware, is always

running too. It is sometimes minimized to a small element (icon) on the right side of the Windows task

bar.

Note: If the EM Sever was closed by the last User, Starting the ZeissSmartSEM software will first

reload the EM server and recover software/hardware communication.

Double click on ZeissSmartSEM icon.

Alternatively, select Start/Programs/SmartSEM/SmartSEM User Interface. The EM Server Lon

On dialogue appears.

By logging, the SmartSEM user interface opens and is ready to operate the tool. By default, a TV view

inside the specimen chamber is shown.

The data zone is a special and useful group of annotation objects which are used to display useful

parameters. If it is not open, select View/Data Zone/Show Data Zone from the menu. Alternatively,

type <Ctrl+D> to toggle the data zone.

Loading the Specimen Holder

Make sure the specimen holder with samples fixed is ready.

(Set up SEM Controls in case it is not setup. Select Tools> Goto Control Panel from the menu to

display the SEM Control panel.)

Annotation bar

Tool bar

Status bar

Data zone

Use mouse to click VAC, and hit VENT, then select YES to the question window. N2 gas is being

introduced into the chamber. OR select Vacuum tab on the SEM Control panel. Click Vent. Click

Yes to confirm the Vent command.

Put on gloves. It takes about 2-3 minutes to vent. Wait and check

until the door can be opened.

Pull the chamber door open carefully and slide the holder onto

the stage.

When chamber open check that o-ring on the door is in place, if not place it in the grove

(must have gloves on while doing this).

Close the door immediately and hold it, then click VAC and hit PUMP. OR Click Pump in the

SEM Control panel.

Wait until vacuum gets to 5∙10-5

Torr before turning EHT on.

Switch ON the EHT

‘EHT’ means the extra-high tension acceleration voltage. This voltage must be applied to the gun to

make the gun emit electrons.

Confirm that EHT Vac ready = Yes is displayed on the Vacuum tab of the SEM Control panel.

Select the Gun tab on the SEM Control panel.

Set the acceleration voltage:

Double-click in the EHT Target = 10 kV.

Enter the required acceleration voltage in the

EHT Target field, for example 10kV,

and click OK.

Switch ON the EHT:

Click EHT in the status bar.

Select EHT on from the pop-up menu.

The EHT switches on and increases to 10 kV.

The accelerating voltage ranges from 200V to 30 kV. Use 10 kV for imaging, 15 or 20 kV for EDS

at the beginning, then tune EHT when needed for different applications.

Position one of your samples below the objective lens using the joy stick with caution. Take great

care not to hit the lens or the detectors. If a detector is damaged by a user, he/she will be billed for

replacement parts.

Once focused, the WD (working distance between the sample surface and the low portion of the

lens) should be greater than 4 mm.

Generating an image

Select the Detector tab on the SEM Control panel.

Select InLensDuo or SE2 detector to display live image.

Find your sample.

(Zeiss recommends to select the SE2 detector to obtain the first image. This is because the

SE2 detector provides a good signal-to-noise ratio even at long working distances.

A few parameters (Magnification / Focus, Brightness / Contrast, Stigmation, Aperture

Alignment) need to be adjusted in order for the SEM to give sharp and high contrast images at a

given EHT and WD. Always do corrects and adjustments at a higher magnification, then acquire an

image at a lower magnification.

Stage settings and motions

The Stage Navigation window can be used to initiate XY movement of the stage by double-clicking

on the sample holder top view. Be sure to select the correct holder from the list and to adjust the

zoom view sliding bar to your needs. All five axes coordinates are reported in this window in order

to save specific positioning on the sample if needed.

The STOP button on the Stage Navigation window or the Break button on the dual joystick can be

clicked at any time to quickly stop any engaged motion of the stage.

Finding your way on the sample is mainly done by the use of the dual joystick panel, where all five

axes can be actuated.

Saving the image

Select the Scanning tab on the SEM Control panel.

Select Freeze on = End Frame in the drop-down list.

Click Freeze.

(A red dot near the lower right corner of the image area

indicates that the image is frozen.)

Select File > Save Image from the SmartSEM menu.

Enter a path and a file name.

Click Save…tif to save the image file.

To continue imaging, select Image > Unfreeze from the SmartSEM menu, or click Unfreeze on

the Scanning tab.

Taking sample OUT

Go to the ChamberScope view.

If Variable Pressure (VP) mode is used, go back to High Vacuum (HV) mode from VP mode.

Click EHT and hit EHT off to turn off the accelerating voltage.

Or go to Gun Beam State = Beam Off EHT off

Move the stage down first. Set the stage back to X=50, Y=50, Z=1, T=0, R=0 using Stage at the

SEM Control window. (Stage automatically will go down to a safe Z position)

Click VAC and hit Vent to vent the SEM specimen chamber.

Put on a pair of gloves.

Once the chamber vented, open the door and remove the specimen holder off the stage.

Close the chamber door immediately. Then click VAC and hit Pump. The chamber must be

pumped down at the end of a session.

Wait for a green tick for VAC.

Go to File and click Logoff. Hit Yes to the two questions.

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

InLensDuo detector is a high resolution secondary electron detector. Below about 1000x

magnification, there will be significant detector artifacts. The detector is top down looking so you lose

shadow contrast making the sample look flatter than it is. Operation is restricted to high vacuum mode

and accelerations ≤ 20kV. Typical parameters are 10kV 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.

SE2 is useful for topographic imaging in high vacuum mode at working distances >4mm. Detector is

for general propose imaging (low-magnification, high-magnification, SE and BSE imaging). Typical

starting acceleration is 5kV, with a working range of 1 – 30kV.

QBSD back-scatter electron detector is good for compositional contrast imaging. WD 6-15mm, EHT:

5kV-30kV.

VPSE G4 detector is for variable pressure imaging of non-conductive samples. 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 cannot be seen in BSD or EDS.

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.

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.

COMMONLY USED HOT-KEY

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 list 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)

Zeiss-specific recipes – starting conditions 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 30µm 10mm

No HC

High resolution imaging InLensDuo 20kV 30µm 5 mm

No HC

Fine surface details InLensDuo 2kV 30µm 5 mm

SE2 No HC

beam sensitive specimen SE2 2kV 20µm 5mm

No HC

Maximum depth of field SE2 10-­‐20kV for

high-­‐Z spec

2-­‐5kV for low-­‐Z

10µm

HC on

10mmforhi-­‐kV

6mm for low kV

Compositional contrast imaging,

conductive

CZ BSD, 4 10-­‐20 kV 60µm ~8.5mm

spec segments active HC on

Surface topography with

composition

CZ BSD, 5 10-­‐20 kV 60µm 10mm

information segments active HC on

Trace element variations CL detector 10-­‐20 kV 60µm 10mm

(VPSE) HC on

nts

Zeiss-specific recipes – starting conditions for non-conductive specimens

Information required Suggested working conditions

(HC = high current mode, HV = high vacuum

mode, VP = variable pressure mode)

Detector Vacuum EHT Apt

/HC

WD mode

Basic topographic imaging VPSE or

CZ BSD, 5

segme

VP

P = 40 Pa

20kV 60µm

HC

on

15mm

High(er) resolution, VP mode VPSE VP 20kV 30µm 8 mm

P = 20 HC on

Fine surface details SE2 HV 2kV 30µm 5 mm

No HC

Beam sensitive specimen SE2 HV 2kV 20µm 5mm

No HC

Maximum depth of field -­‐ VP mode VPSE VP 20kV 30µm 15mm

P= 40 HC on

Compositional contrast imaging CZ BSD, 4 VP 20 kV 60µm ~8.5mm

segments P = 40 HC on

active

Surface topography with composition CZ BSD, 5 VP 20 kV 60µm 10 -­‐ 15mm information segments P=40 HC on

active