NANYTE BEAM Manual
NANYTE BEAM Manual BM-001-A3 / V1.1a Page 31 of 33
Stage levelling
To ensure that the stage is parallel to the x and y stepper axis, stage levelling is required. Insert a
large polished silicon substrate (> 3 x 3 cm) onto the sample stage and position BEAM ENGINE
on the silicon substrate. Do not use silicon substrates that are spin-coated as it is common to
have photoresist residue on the underside and may cause the sample to not be parallel to the
stage.
To perform stage levelling, click on the levelling button on the main window. This will move the
BEAM ENGINE along the x and y directions while capturing the focus level. This allows the tilt
along the x and y axis to be calculated.
Tilt Reading
Adjustment
+x Turn right knob ACW and left knob CW by same amount
-x Turn right knob CW and left knob ACW by same amount
-y Turn right knob ACW and left knob ACW by same amount
+y Turn right knob CW and left knob CW by same amount
Repeat the adjustments until the reading is below ±5 z/x and ±5 z/y. Since the z-displacement
is presented as steps of 150 nm, the threshold can be understood as 750 nm z displacement
over 1000 um x displacement.
Focus calibration
Calibrating the autofocus
The built-in focus feedback can provide information on whether the camera image is focused.
However, to make this fast and reliable, machine learning algorithms are applied and requires
calibration to train the machine learning model.
Before performing the calibration, insert a clean polished silicon substrate onto the sample stage
and position BEAM ENGINE on the silicon substrate. Find a piece of dust and bring it into focus
manually using the mouse scroll wheel. This will set the current focus level as the zero focus level.
Ensure that a flat and level substrate is used and that stage levelling has been performed.
Click calibrate focus to start. The stage z-axis will move to an extreme defocused z-level and
slowly move into the focus region. Eventually it passes the focus region and reaches the other
extreme. Once the focus calibration is done, the stage returns to its focused position. You can
test if the autofocus is working properly by pressing the ‘F’ key at various locations of the wafer.
Despite not having any dust, the system should be able to focus.
Watch out for a warning message which informs of the stage focus oscillating. This means that
the autofocus is unable to converge to the zero-focus level with high precision, but acceptable
enough for lower resolution patterning works.
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