You should try the SU-8 adhesion promoters that are on the market.  MCC
and Silicon Resources in Chandler Arizona both have products that work
well.  What type of wafer are you using?

Best Regards,

Garrett Oakes

EV Group
invent * innovate * implement
Northwest Strategic Account Manager

-----Original Message-----
From: Jose Guevarra [mailto:[email protected]]
Sent: Friday, August 01, 2008 11:46 AM
To: General MEMS discussion
Subject: [mems-talk] SU-8 2025 and 80 micron high features w/ HMDS?

Hi,

  I'm trying to make some features of about 70 to 80 microns high with
SU-8 2025. I've used the recipe below. However, after the develop and
hard bake the photoresist starts to come off the wafer. So it seems it's
a bonding issue.  Can anyone recommend a recipe for 70 micron high
features with SU-8 2025?

Would a layer of HMDS help the SU-8 bond to the wafer?

Thanks.

----------
1. PhotoResist
      - Spin 8 sec 500 rpm
      - Spread 30 sec 1250 rpm
      - May Need to wipe perimeter of wafer for excess photoresist

2. Soft Bake
     - 65 deg. C 2 min
     - 95 deg. C 8 min
     - If wrinkles form on cool down try heating up and cooling down
again

3. Exposure
     - 20 sec

4. PEB
     - 65 deg. C 1.5 min
     - 95 deg. C 6.5 min

5. Develop
     - Su-8 developer for 6 min

6. Descum

7. Hard Bake
     - Heat from 65 deg C to 160 deg C
     - Let sit at 160 deg C for 10 min
     - Cool down to room temp
----------------------------------