Hi;
Your hard bake temperature is very high.  You should bake less than 2000C in
long time.

Did you use the standart recipe of the SU8-2000

Tolga YELBOGA
Project Engineer
Nanotechnology Researh Center
Bilkent University
Bilkent, Ankara 06800 TURKEY
Voice: 90-312-290-1020
http://www.nanointurkey.com
http://www.nanotam.bilkent.edu.tr

-----Original Message-----
From: dai truong [mailto:daitruongvl@yahoo.com]
Sent: Friday, August 22, 2008 5:04 AM
To: General MEMS discussion
Subject: [mems-talk] Polyimide

Hi all,
I have used polyimide SU8-2000.5 with a process as following:

..         Spin PR (SU8 2000.5): 10 seconds
500rpm and 30 seconds 3000 rpm (expected PR film thickness 500nm)
..         Soft bake: 60 seconds
..         Expose: 5 seconds
..         Post Expose bake (PEB): bake at 950C
in 90 seconds
..         Development: 70 seconds and rinse in
IPA 10 seconds
 .       Hard bake (Cure): 2000C
in 15 mins

but after all, the SU 8-2000.5 film thickness is only  about 300nm, and on
the surface some holes occur.  how I can get 500nm-thickness film and cure
temperature is enough.
thanks