There are 2 possible reasons that your SU-8 does not stick to the wafer:
1.  Your batch of SU-8 is expired.
2.  The wafer you used is not sufficiently clean.  Either wash it with =
acetone and dry it on the hotplate, or use SC-1 clean (NH4OH:H2O2:H2O =
=3D 1:1:5 at 65'C) for about 10mins.
=20
Jeffrey

________________________________

From: [email protected] on behalf of [email protected]
Sent: Thu 3/8/2007 12:03 PM
To: General MEMS discussion
Subject: [mems-talk] Methods to make thick resist layer

Thanks a lot the input I've received. It looks like I have two choices.
1. Double spincoat with az4562 or 9260. Is there anything special in
the double coat process?
2. Ultrasonic development (I don't have magasonic transducer) using
su8. Recently I found my su8 doesn't stick very well onto wafer during
development. Features simply came off. This never happened to me
before. I was following the datasheet and not using HMDS or other
primer.