I run into this problem frequently with AZ2035, a negative resist. The
problem occurs with negative resists if you take the resist above a
certain temperature (~125C for AZ2035), or if you use CF4 plasma, even
at low temperatures.

I remove the baked-on resist using hot AZ Kwik Strip, but I imagine
other photoresist strippers will work. 5 minutes in a bath of Kwik Strip
with the hotplate set to 100C, and the resist is gone. Alternatively, an
overnight soak at room temperature seems to work.

The same technique works if the resist gets too hot during a liftoff
metal deposition. If liftoff fails in acetone, try using hot photoresist
stripper instead. I have saved many samples this way.

I would recommend trying the overnight soak first, and if that doesn't
work then make sure you take appropriate precautionary steps when
heating up Kwik Strip, or whatever stripper you use.

Regards
Jason Milne
Microelectronics Research Group
The University of Western Australia


-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Satish Yeldandi
Sent: Tuesday, 20 May 2008 11:01 AM
To: General MEMS discussion
Subject: [mems-talk] PR removal after ICP RIE etching

Hi!

I have problem removing photo resist after using it as mask for
ICP-RIE etching. I tried Acetone, Acetone+Sonication, PR stripper,
Asher. Nothing is working. Did anyone face this problem before. If
anyone has any solution for this problem please tell me.

Thanks
Satish