Associated Documents and References

• VEGA3 instructions for use
• Help contents of the MiraTC software

Equipment Used

• Control panel
• Trackball
• Keyboard
• Sample holders

Procedure

• Prior using the tool
• Start-up
• Sample preparation
• Sample loading
• Full view of the carousel
• Beam and Image setup
• Electron-beam adjustment at high magnification
• Specific imaging conditions
• Sample unloading
• Log off from the software

Prior using the tool

• Check the status in Coral or consult the website

Start-up

• Enable the tool in Coral 
• Log in with your user name and password.
  
• Verify the system status and the gun pressure in the Vacuum panel. It is possible that the column pressure is in red color because the system is on standby mode.

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Sample Preparation

• Mount your sample on the appropriate holder with conductive tape (carbon or copper) or copper clips.

Holders available:

- Standard 1/2 inch stubs

- Cylinder mount with double walls at 90° for cross-section views

- 4 inch wafer holder

- 6 inch wafer holder

Note: Max. 2 standard stubs can be provided to you. They can be purchased from Soquelec (http://www.soquelec.ca/semsup17.asp).

Warning: the default stage configuration is for the standard 7-stub carousel. If you plan to do imaging on a 4 " or 6" wafer, contact the staff first. 
The stage configuration must be modified so that the right collision model for wafer holders is loaded.

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Sample loading

• Vent the microscope by using the VENT button in the Vacuum panel.
• Open the chamber door by gently pulling it.
• Click the appropriate number button on the carousel in the Stage Control panel.

Warning: Do not touch any part of the stage when moving.

• Place the specimen stub and tight slighly the corresponding screw with the 1.5 mm hexagonal screwdriver.
• Repeat the 2 previous steps if you need to load several stubs (up to 7 on the standard carousel).

• Close the chamber door.
• Click the PUMP button in the Vacuum panel. Ensure that the chamber door is properly closed: put your hand on the door to maintain proper seal during the first seconds of pumping.

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Full view of the carousel

If you have several stubs on the carousel, the Wide Field mode will help you find an area of interest by viewing the whole carousel.

• Select the accelerating voltage in the Electron Beam panel.
• Click the HV button if the system has been left on standby in the Electron Beam panel. Otherwise, click the Heat button.
• Right-click in the SEM scanning Window and select Minimum Magnification.
• Click the Scan Mode function in the Info Panel and select the WIDE FIELD mode.
• Set the beam intensity at 10 by using the BI knob on the control panel.

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Beam and Image setup

• Select the appropriate detector (SE or BSE) in the SEM Detectors & Mixer panel.

Warning: If the BSE detector is used, make sure that it is not retracted. Click the Push in button in the Motorized RBSE panel.

• Select the accelerating voltage in the Electron Beam panel.
• If not done, click the HV button if the system has been left on standby in the Electron Beam panel. Otherwise, click the Heat button.
• Right-click in the SEM scanning Window and select Minimum Magnification.
• Click the Scan Mode function in the Info Panel and select the RESOLUTION mode.
• Set the beam intensity at 10 by using the BI knob on the control panel.
• Focus the image on the sample by using the WD knob on the control panel. Alternatively click the WD icon in the toolbar and turn the trackball from left to right or vice versa.
• Adjust brightness and contract if necessary.
• Set WD&Z to 15 mm in the Stage Control panel. The focus will be automatically adjusted during stage movement.

Warning: Z corresponds to the physical height of the stage and is not necessarily linked to the working distance. 
Do not use it at any time as it can cause damage to the objective lens.  

• Adjust the beam intensity according to the resolution you need.
• Set the magnification between x2000 and x5000.
• Focus the image.
• Perform the Auto Gun Centering procedure by clicking the Adjustment button in the Electron Beam panel.
• Focus the image on the sample.
• Press D on the keyboard to degauss the column and redo the focus if needed.
• Set the desired WD&Z value.

Warning: when the BSE detector is used, the minimum working distance is 8 mm.

• Adjust the brightness and contrast.

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Electron beam adjusment at high magnification

• Set the magnification above x10,000
• Select the Manual column centering function (wobbler) by either using the combo box on the Electron beam panel after clicking on the Adjustment button or clicking the WOB icon in the toolbar. The Manual Centering Wizard window will appear. Clicking on the WOB button opens the Focus window in the SEM Scanning window. Click on the Next>> button to obtain the next instructions.
• Adjust the focus
• Press D to degauss the column and redo the focus if needed.
• Click either on the Stigmator function on the Info Panel or on the Stigmator icon in the toolbar. Correct the astigmatism with the knobs on the control panel or with the trackball.

Note: When there is astigmatism, the image looks like it is stretching in one direction at an over focused and under-focused condition, and uniformly focused at the best-focus point.

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Specific imaging conditions

Non-conductive samples

For secondary electron imaging, samples must be electrically conductive. Some non-conductive samples can be handled at very low acceleration voltages (< 5 kV). Otherwise they can be coated with a thin film of carbon, gold or other conductive material to obtain conductivity without significantly affecting observed surface morphology.

Tilted view

Warning: the position of the stub on the carousel is important for tilted views. It must be mounted at a position from #1 to #6. 

• Lower the stage at least at WD&Z=10 mm to prevent any damage on the objective lens.
• Select the appropriate number button on the carousel.
  
• Check the Keep view field box in the Stage Control panel.
• Note the stage rotation value. Subtract or add 180 and enter the new value in the Rot field.
• Find the area of interest on the sample.
• Select the DEPTH mode in the Info Panel if you don't need high resolution (< 500 nm).
  
• Minimize the image movement by using the Manual column centering function at high magnification.
• Set the desired tilt angle in the StageControl panel.
• Reduce carefully the working distance if possible.
  

Warning: the carousel must always be below the objective lens plane for tilted views.

• If measurements are done on the tilted sample, apply a tilt correction in the Geometric Transformations dialog. Open the SEM menu and select Geometric Transformations item or click the second button from left in the Main Toolbar panel.

Backscattered electrons

• Set WD&Z at least at 8 mm.
• Click the Push in button in the Motorized RSBE panel.

Warning: be careful if you have several samples of different sizes. Big and incorrectly placed specimens can hit the detector and cause its damage.

• Either select the BSE detector for Channel A or A|B mode for simultaneous acquisition in the SEM Detectors & Mixer panel .
• Adjust the brightness and contrast.
  

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Sample unloading

• Retract the BSE detector if used.
• Click the HOME button in the Stage Control panel.
• Click the Heat button to turn off heating of the filament in the Electron Beam panel.
• Click the VENT button in the Vacuum panel.
• Open the chamber door.
• Click the appropriate button on the carousel in the Stage Control panel.

Warning: Do not touch any part of the stage when moving.

• Unload the speciment stub.
• Close the chamber door.
• Click the PUMP button in the Vacuum panel. Ensure that the chamber door is properly closed.

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Log off from the software

• Wait for the vacuum ready-status (green color). 
• Put the system in standby if you are the last user of the day.
• Log off in File menu.

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