Andrew great choice of processing.  The real secret is not allowing moisture to
get back on the wafer.  With vacuum priming the vacuum dehydrates and then the
primer reacts with the wafer  with no chance of moisture seeing the wafer.  The
chemistries that work best for SU8 which is an epoxy based resist are either
APTES, APTMS or 3-GOPS.  The vapor pressure of these chemistries is such that a
simple vacuum vapor primer cannot work.  We have developed different units the
1224P or the LabKote for special vapor pressure chemicals.

Bill Moffat

-----Original Message-----
From: [email protected] [mailto:mems-
[email protected]] On Behalf Of Andrew
Sarangan
Sent: Saturday, December 11, 2010 9:15 PM
To: General MEMS discussion
Subject: Re: [mems-talk] SU-8 3000 vs 2000 adhesion

I have also noticed some detrimental effects of HMDS on SU8. What has worked for
me is an etch clean of the wafer, vacuum bake and then quickly spin the SU8
while the wafer is still warm. The soft and post bake have to be ramped very
slowly, about 5C every 2 mins.