HMDS will likely help.  It can be applied either in the vapor phase using a
hot plate or alternatively in the liquid phase by dispensing on the wafer
allowing about 30 seconds for a puddle of the material to remain on the
wafer and then spin off the excess followed by the spin on coat.

Gary Hillman
S-Cubed
PO Box 365
9 Mars Ct.
Montville, NJ 07039
phone 973-263-0640 ex 35
fax 973-263-8888

-----Original Message-----
From: mems-talk-bounces+garyh=s-cubed.com@memsnet.org
[mailto:mems-talk-bounces+garyh=s-cubed.com@memsnet.org]On Behalf Of hui
yan
Sent: Tuesday, January 25, 2011 12:56 AM
To: mems-talk@memsnet.org
Subject: [mems-talk] AZP4620 peels off

i m using positive photoresist AZP4620 for photolithography. However, during
the development step, the resist layer peels off when washed with DI water;
though i have tried numerous times and have shorten the development time to
20s.

I have cleaned my wafer using piranha solution, followed by DI water rinse,
then rinsing with acetone, IPA, DI water. And then dehydrate my wafer at 120
C for 30 min.

Does HMDS primer helps? if so, what is the recipe for spin coating it?

Regards,
Hui Yan
Mechanical Engineering
National University of Singapore