Hello Jeffrey.

Maybe the substrate temperature was too high during metallization
process.
It should not exceed the usual soft bake temperature for AZ9260, or else
at least some resist is not soluble anymore in Acetone or other
solvents.

If the temperature (hard bake) cannot be avoided, ashing might be the
only alternative.

Best Regards,

Norbert Nodes

N.Nodes@EVGroup.com
www.EVGroup.com

-----Original Message-----
From: mems-talk-bounces@memsnet.org
[mailto:mems-talk-bounces@memsnet.org] On Behalf Of Yue Mun Pun, Jeffrey
Sent: Montag, 06. August 2007 11:09
To: mems-talk@memsnet.org
Subject: [mems-talk] Lift-off process

Hi,
I am attempting a lift-off technique to pattern gold.  I have patterned
7-8um of AZ9260 on SiO2 wafers and evaporated 10nm Chromium followed by
300nm Gold through the patterns in the AZ9260 resist.  Subsequently I
have lifted off most of the resist by soaking the wafers in Acetone over
2 days.  However I have noticed that there are some resist residue that
won't be lift-off even after sonication.  The sonication process also
leaves a lot of debris on the wafer.
I am trying to remove these debris and the remaining residue by soaking
the wafers overnight in AZ300T Stripper.  Does anyone have an
alternative technique to suggest to clean the wafers?  I have tried
using H2SO4:H2O2 = 3:1 (piranha) by it may damage by structures, so I
refrain from using this technique.