Ken:

I have used SU-8 for DRIE and found it to have much higher selectivity than
standard positive photoresist. We were able to pattern an SU-8 formulation
that was only 5 microns thick and do DRIE without cross-linking thus we were
able to ash the photoresist off after etch. It worked well.

Bob Henderson

-----Original Message-----
From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org]
On Behalf Of renil kumar
Sent: Tuesday, September 08, 2009 3:42 AM
To: mems-talk@memsnet.org
Subject: [mems-talk] SU8

Hi All,
                   Does anyone know the selectivity between SU8 and Silicon
in DRIE environment. can i use SU8 as a hard mask during DRIE process. I
want to etch 30 um down to the silicon wafer to form 1.2 um thick vertical
walls for that i am using e-beam lithography. i will be grateful for any
suggestion regarding this. thanking you.