NANYTE BEAM Manual
NANYTE BEAM Manual BM-001-A3 / V1.1a Page 30 of 33
Laser calibrations
PI curve
Besides the spatial calibrations, the laser output should also be calibrated. This is especially
because the laser power does not vary linearly with laser current. A photodiode is installed
within each BEAM ENGINE that allows for self-calibration. Click the calibrate button to start the
calibration.
If a precise dose is of a significant concern, please contact NANYTE for yearly calibrations. For
most use cases, the dose can be treated as a relative value, and such yearly calibrations are not
necessary.
Spatial power calibration
Similar to the galvo calibration, the laser power is also affected by vignetting of the optics. This
results in a spatially varying laser power that is generally more powerful in the middle and weaker
on the peripherals. To perform the spatial calibration, a photodiode is included on the top right of
the sample stage. The photo diode is recessed so that 5” wafers can be placed without
obstruction.
Clicking the calibrate button, the stage moves to the stage-mounted photodiode position and
begins to scan the laser spot across the entire field of view. At each point, the measured
photocurrent is also stored, thus the spatial calibration can be obtained by second order fitting.
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