fei novanano feg-sem 630. technical objective to train you to use the fei feg hr-sem electron...

FEI NovaNano FEG-SEM 630

Technical Objective

• To train you to use the FEI FEG HR-SEM electron microscope

• High vacuum operation for conductive samples• Low vacuum operation for non-conductive

samples and avoidance of “crud deposition”• This machine requires your full attention

– Very easy to damage– Very expensive to repair– Damage is not covered under the very expensive

service contract

Vacuum system layout

Chamber

Ion Getter pumps

Turbo pump

Scroll pump

Capacitance gage

Cold cathode gage (Penning)

Chamber

Scroll pump(Oil-free)

IR CCD camera

Ion getterpumps

Ion getter pumps

Everhart – Thornley detector

Specimen current monitor

Plasma cleaner

Cold cathode ion gage

Plasma head

Low vac detector power supply

Door!(Linear Bearings)

Aperture adjustmentOuter ring: sizeInner ring: position

Height adjusting “elephant”“600 A”

Stage

Height gage“elephant”“600 A”

Sampleholder

Sample mounting fixture

IR CCD

Pole piece(No detectors attached

Everhart-ThornleyDetector

Low Vac detector jack

Console

Accounting systemUser interface

Knob panel

Brightness

Contrast

Stigmation FocusImage Shift

MagnificationCoarse

Fine

Sample Mounting

• FEI uses mounting stubs with 1/8” shafts• Carbon tape (double sticky) is simplest• Carbon dots have lower vapor pressure• Multiple samples can be mounted on “turret”• Make a drawing in your research notebook of the

locations of your samples on the “turret”• Sample locations are 19 mm apart and 19 mm off center• Single mount is easiest for tilting; tilting the “turret” will be

extremely dangerous• Vertical mount is also an option• Tighten gently with Allen wrench; ditto for sample holder

on stage

Notes on the computer

• Left computer is “support computer”: left monitor– Connected to the internet– No internet use whatsoever except data transfer– Use USB ports on front to extract your data– Never install software

• Right computer runs microscope: right monitor– Never insert a memory stick– Never change anything– Never, ever, ever install software!

• Move between computers by moving mouse left or right

Administrative matters

• Nothing in life is free• Log onto the SEM with the sheet on the desktop• Enter your name• Enter the name and contact information of

whoever will be paying• Record how many times you coated samples• Enter the time of day when you start.• Enter the time of day when you finish.• If we learn that your times are inaccurate, you

will be required to pay an operator to document your time

Getting started with the FEI NovaNano HR-SEM

• Typical conditions when you walk in:– All pumps are running– High Voltage is off– FEG is hot (FEG is always

hot!)

Status module

Random stuff

• F5 cycles between full screen and 4-quad mode.

• Activate one of the four quadrants by clicking anywhere in it. The databar at the bottom will become blue.

• Double green bars in the upper right-hand corner of an image mean that it has been paused and is not active

• Un-pause a window by clicking on the pause button on the button bar

How the software works

Right click to access these options

Starting and stopping the control softwareOn desktop

Tool bar and button bar(Many SEM functions are mouse-controlled)

Log off user: log off when you are done!

User

Use “Open” to Import an image

Use “Save as” the first timeyou save an image

Extremely useful when you have no image!

“Horizontal line”: current raster

..and e-beam lithography!

This must be done every timeThe softwareIs rebooted.n.b.! Stage willtilt; your samplewill fall off if not fastened!

Magnification control options

• Conductive or non-conducting sample? – High vacuum for conductive– Low vacuum for non-conductive (coat if possible)

• Install low-vac detector

• Choose initial parameters– High voltage (20 kV) for maximum resolution– Low voltage (1-3 kV) for maximum topographic detail– Low current (spot size 1-2) for max resolution– Higher current for better signal-to-noise

To insert your sample

• Check that high voltage (HV) is off (no yellow background)

• Click on Vent• Insert sample. Wear gloves or use tools.• Check sample height with “elephant nose”. Bottom of

nose is where highest point on sample should be.• Click on quadrant showing CCD image• Make sure image is live, not paused! (No double green

bars in upper right corner.)• Slowly close door while watching monitor to assure that

sample/holder is clear of pole piece and detector• Click on “Pump” with left hand while holding door shut

with right hand. Check that door is shut!

Getting started toward an image

• When adequate vacuum has been reached, chamber icon becomes green and HV button changes from grey to black.

• Click on HV!

•

Get an image!

• Black screen:– Check that H(igh) V(oltage) is on: yellow background?

• HV automatically shuts off when switching between High Vac and Low Vac!

– Go to minimum magnification• Can you see the aperture?• If not, you are in big trouble. Check HV!• Try spot size = 4, 15 kV

– Turn on waveform feature• Increase contrast and brightness so waveform fills region

between lines

Link • Initially your stage should be about 13 mm down..but

could be anywhere: it has no way of knowing where you mounted the top of your sample!

• Focus• Increase magnification• Focus• Link• Z-coordinate is now correct• Less crucial if using only samples of minimal thickness• Absolutely crucial for samples of widely varying

thickness• Extremely crucial if sample is taller than elephant nose!

Image optimization

• With Everhart-Thornley or Low Vac Detector, raise stage to about 5 mm – Typically during pump-down with roller ball – With cursor low on screen, press roller ball

and roll mouse up– Watch active (not paused!) image of sample

mount on CCD– Translation speed is proportional to distance

cursor is from starting point

• Increase magnification

• Re-adjust focus

• Repeat process

• At about 5kX, link

• Raise sample to 5 mm

• Switch to TLD (Through Lens Detector)

• Re-focus

• Go to immersion mode

• Optimize image

Ian’s Recipe for Image Optimization• Set reduced raster to a tall, narrow box• Scan as rapidly as allowed by contrast• Try to focus on a vertical feature• Adjust stigmation for optimal image• Move box across screen if object degrades• Blank beam• Shift stage or beam to virgin sample (arrow keys move

state 80% of screen dimension)• Return to full screen scanning• Reduce scan speed for high image quality• CTRL R restarts scan• Immediately un-blank beam• Click “Pause”

Labeling your Image

(At the bottom of the Scan menu)

To save your image

• Pause symbol will blink as image scans• Pause symbol will stop blinking when scanning has

stopped• Insert memory stick into Support (left) pc• File/Save as…• Choose “Network places”• Choose e:USB…on Support pc• Choose an appropriate filename for your sample,

preferably ending in …_001.tif• For black and white images, choose tif8• For images with color markings (labels), choose tif24

Beam Detectors Navigation Processing Control

Double click toenter arbitrary number

Right menu common to “all” “pages”

“Pages”

Beam control

Focus wobble

Probably better to start via the “crosshair target” button on the button bar.

Immersion mode

Apertures

• Available sizes and uses– 2@30 μm: highest resolution– 40 μm: low kV, low vac– 50 μm: low kV, EDX– 100 μm: EDX– 1 mm: for service engineer for alignment

• Apertures are changed mechanically by rotating the knob on the side of the column…the one on the right

• After changing apertures it is necessary to align it with the screws on the sides (coarse beam align)

• Also “manually” change the value stored for “aperture” under the “beam” menu

Detectors page

Proper grid voltage is very important in Low vac mode

Choose detectorChoose operating mode:SE BSECharge neutralizationDown-hole

High vacuumEverhart ThornleyTLD

Low vacLVDHelix

STEM

Secondary electrons give best topographic InformationBSE give elemental contrast

TLD has four operating modesTHROUGH THE LENS DETECTOR (TLD)

Secondary electronBackscatter electronCharge NeutralizationDown-hole visibility

ETD and TLD both feed the same output, soyou cannot view them simultaneously. You canview them sequentially in Quad 1 and Quad 2, then mix the images in Quad 3.

Magnetic hazards

• Ferromagnetic particles are potentially the most dangerous thing you can image

• If they get sucked into the column, the rebuild will cost $60-100k!

• Trying to image loose ferromagnetic particles in immersion mode will be fatal!!!

• They can be imaged in EDX mode• They can be imaged in immersion mode if firmly

embedded in plastic. Do not use tape!!

Secondary Electron Detector

Backscattered Electron Detector

Fractured Aluminum

More stuff on running the NovaNano

• The generic working distance for the NovaNano is 5 mm. – ETD– TLD– LVD– Also the eucentric working distance – Focus to at least 5000X, then Link. Do this

early in the process. Do it repeatedly…especially if using the Helix detector

Furthermore

• If you are using the 2-sample holder, the pins are 16 mm apart

• If you are using the 8-sample holder, the pins are 19 mm apart.– Always make a drawing of the locations of

your samples on the holder– Be extremely careful of orientation: get the

sides of the holder on the translation axes– Remember that the CCD camera is mounted

in the rear of the chamber

Further still more• You can move the stage in the x- and y-

directions by typing coordinates into the boxes in the “Navigation” page

• You can also move the stage from the image (not CCD) by holding down the roller ball and moving the mouse– The arrow points in the direction you want to

look– The arrow points in the direction opposite to

the one in which the stage moves

Still further more yet

• If you raise the stage by typing a value into the box on the “Navigation” page– Activate by clicking the GoTo button– “GoTo” will immediately change to “Stop”– Watch the rising stage on the CCD monitor– If the stage is in danger of hitting the detector

or pole piece, immediately click “Stop”– “Escape” is an alternative “Panic button”

• “"When I Use a Word, It Means Precisely What I Want It To Mean....“ Humpty Dumpty

• In the lexicon of Leo, “Beam current” is the current leaving the filament and “Probe current” is an approximation to the current incident on the sample, usually high by about a factor of two.

• From FEI, “Beam current” is an excellent approximation to the current actually striking the sample.

Low vacuum

• Why? For non-conducting samples or when you want to avoid rapid deposition of crud on your sample.

• ETD does not work• New detector must be installed…while wearing

gloves– LVD is relatively cheap and adequate for images up

to about 50 kX– Helix is very expensive but gives killer images on non-

conducting samples to 500 kX or more!• PLA must be installed sufficiently tightly that it

does not leak and kill the column

Pressure limiting Aperture (PLA)