Are you seeing iregularly shaped circular features when writing RAITH circles?
jwc at snf.stanford.edu
Thu Apr 29 09:00:29 PDT 2004
Greetings Raith Community:
Several users have reported that their Photonic Crystal circles written
with RAITH circle function have been elliptical or not completely
cleared out on positive PMMA resist.
I am working with several users on this and may have identified two
trends that could result in this phenomenon.
1. Beam speeds are allowed to be too high!! Be sure to inspect your
exposure window and ensure that the area write and line write beam
speeds are below 10 mm / second. This is to ensure you do not
experience fly back effects as the data arrives to the deflection system
before the beam reached it proper position. This is likely a result of
using old parameters and aperture selections with the new improved Beam
current we achieved after the recent PM. Features written in the X
direction will become elongated, circles become ovals.
2. Area steps are too big!! Note that the area step parameter is
employed to place the RAITH single pixel line (SPL) in the pattern
written in RAITH circle mode. This will result in shots that do not
connect or overlap during your EBL write.
Features written will have very rough line edge roughness and have an
appearance of swiss cheese or closed area of your circles.
Other users observing this or other strange write results are requested
to report to this list and include measurements and images if possible.
You may stop by during my office hour as well.
Thank you for your support!
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