As stated the HMDS will not help much with the issue.  However doing
dehydration bake may help.  Another product that I have had a lot of
success with adhesion promotion of SU8 is a product called AP300 not to
be confused with AP3000 which is made for BCB.

AP300 is made by a company called silicon resources; you can get more
information from their website.

Best Regards,

Mike Sexton

EV Group       invent * innovate * implement

Process Engineer - Technology - Tel: 480.727.6355, Fax: 480.727.9700
e-mail: m.sexton@EVGroup.com,  www.EVGroup.com



-----Original Message-----
From: mems-talk-bounces@memsnet.org
[mailto:mems-talk-bounces@memsnet.org] On Behalf Of Steven Yang
Sent: Friday, January 11, 2008 2:10 AM
To: mems-talk
Subject: [mems-talk] How to improve SU-8 adhesion?

Hi, all

Asked some questions on SU-8 2050 several days ago, still stuck on it
now.

The problem is the peeling off at some SU-8 2050 microchannel
edge.(SU-8 2050 on PECVD SiO2). Without SiO2 layer, the situation will
get better with seldom cracking and peeling off. However, on PECVD
SiO2 it always turns out this problem more or less.

I have increased the temperature and time for dehrydration at 180C for
30mins. and exposured for 40s at 7mW/cm2, PEB at 65C, 95C for 5 and 15
mins respectively (Same as softbake). No much different.

If there is no any further solution based on recipe modification, will
the HMDS get the thing better? If so, could anyone give some
suggestion on the HMDS spin procedure? below is what I plan to do.
1) dehydrate at 150C for 15mins
2) spin HMDS at 7500rpm for 35s
3) dehydrate at 150C for another 15mins
4) spin SU-8 2050 at 4000rpm for 45s

Any suggestion?