Try a photoresist stripper.  I'm not aware of acetone as an ingredient
in any commercially made resist stripper.

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Sven Holmström
Sent: Wednesday, December 21, 2005 4:01 AM
To: [email protected]
Subject: [mems-talk] Removing dry resist


Hi

We have a problem regarding the removal of resist.

We have two wafers with memsstructure of aliminum and gold respectively.
We want to release them by etching a sacrificial crome layer. On top of
the crome a protective layer of Shipley's S1813 resist was put to
protect the wafers durings transport.

The resist was only softbaked after spinning.

What obviously happened was that the wafers were stored for too long
(around six moths) and now the resist can't be stripped by acetone,
which is what we normally use.

Can anyone here think of any other way to remove the resist? It might be
possible to etch itm but most ethcants etch metals faster than resists,
which would be a big problem.