7 CalEuentricFocus

Example 7. CalEuentricFocus

 
MacroName CalEucentricFocus
# macro to calibrate EucentriFocus using F 
# update @ 2014-10-22 07:55:56

Echo ===> Running CalEucentricFocus ...

# use SEM built-in wobbling way to get to Eucentricity
Eucentricity 3

## record original TargetDefocus
ReportTargetDefocus 
orig = $reportedValue1

## make sure TargetDefocus is at 0
SetTargetDefocus 0

## bring Objective to eucentric
## not to normalize because beam will be 
## drifting afterwards.

#NormalizeLenses 2
#Delay 1
Loop 3
	G
EndLoop

## Cal - record the value in memory, unless in admin mode
## and save it to calibration file.
CalEucentricFocus

## restore original target defocus
SetTargetDefocus $orig

As we see from macro Z_byG and Z_byV, it is key to have EucentriFocus calibrated accurately for these two macros to work accurately.

Normally, if we calibrate this EucentriFocus manually for a specific magnification, we follow the procedure as following.

  1. Make sure the specimen is at Eucentricity or we call Eucentric Height. We can run Eucentric Both on a specimen area with good signal and clear features. It is useful to double check how it is when the routine finishes. One can take shot and tilt stage an angle like -45 degree and take another shot. Comparing the two shots gives idea if the sample is truly at Eucentricity.

  2. Set Target Defocus to 0.

  3. Autofocus for a few times, until the defocus is adjusted to very close to focus. It is recommended to normalize Objective Lens before Autofocus.

  4. From menu, Calibration → Focus & AutoFocus → Standard Focus.

These steps can be done with a single macro as above.

Note: this is to be done at each magnification that will be used for this purpose. Administrator perhaps has done for most of the magnifications. Therefore, the calibration file has these values already. However, as you might use a slightly different scope alignment from what the calibration was done with, it is the best to do this calibration at beginning of your session as an user. This macro is aim to make this task easy.