James:

This has been a long time ago but if I remember right we treated it just
like negative working resist. That is we had a special SU8 that would
produce a 5 micron film at 3,000 rpm spin speed. After coat we did a soft
bake at 70 degrees C for 30 minutes in a Blue M oven. Then we exposed on a
contact aligner to cross-link the exposed areas with proper wavelength of
light. Then we developed using Xylene followed by N-Butyl Acetate for a
rinse. The sidewall profile was 90 degrees and it had much better
selectivity to a silicon etch than any positive resist we tried. That is all
I remember but you can contact MicroChem as I am sure they have advanced
the formulations since then.

Bob Henderson

-----Original Message-----
From: [email protected] [mailto:[email protected]]
On Behalf Of James Paul Grant
Sent: Tuesday, September 15, 2009 9:05 AM
To: General MEMS discussion
Subject: Re: [mems-talk] SU8

Hi Bob,

Could you please elaborate more on how you achieved successful pattern
transfer without using a post exposure bake? The post expsure bake is
required to cross-link exposed areas of the SU8. If you omit this step
then surely at the development stage your SU8 will simply wash off? If
you have found some way of using  SU8 as a  hard mask without the need
for a  post exposure bake then that would be something....

Best regards

James Grant