Hi,



I have quartz wafers covered with reflowed photoresist. I am etching these
with a mixed CH4 and O2 plasma. Hopefully, I will be able to adjust the
height of the resulting optic by changing the gas concentrations (with CH4
etching the glass and O2 etching the photoresist). Right now, the optics
that come out of the plasma etcher are very rough-much rougher than the
photoresist profiles that shaped them. Under a microscope, I see many cracks
in the surface of the quartz. The "bumpiness" is on the order of 1/3 of a
micron (where the optic height is 1 - 2 microns). I am running at a pressure
of 150 mTorr, with gas flow rates of 100 cc/m for CH4 and 50 cc/m for O2,
and 83 W of RF power. If anyone has experience etching glass with reflowed
photoresist, their advice would be much appreciated!



Thanks!



Patrick Lu

Stanford University

Department of Electrical Engineering

http://www.stanford.edu/~patlu