I have had good luck using a very long O2 plasma clean (24 hours!).  Also,
you might want to use resist stripper or ethanol for the initial lift off,
acetone can leave a lot of crud behind.

David Nemeth

-----Original Message-----
From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org]
On Behalf Of Yue Mun Pun, Jeffrey
Sent: Monday, August 06, 2007 5:09 AM
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.