Evan, standard positive resist and image reversal so far up to 40 um,
creates reverse profile for perfect lift off.  Bill Moffat.

-----Original Message-----
From: mems-talk-bounces@memsnet.org
[mailto:mems-talk-bounces@memsnet.org] On Behalf Of Evan Lunt
Sent: Wednesday, November 11, 2009 3:41 PM
To: mems-talk@memsnet.org
Subject: [mems-talk] Partial development of Su-8

I would like to partially develop a 5-10 um-thick Su-8 film on a Si
wafer.
After the partial development, I am going to deposit a thin metal layer
and perform a liftoff by finishing the Su-8 development. So far, I have
experienced two major problems with this:

1. Su-8 developer is removing the unexposed Su-8 too quickly. Is there
any way to slow down the development (i.e. dilution)? I would like to
avoid excessive baking of the wafer.

2. As is widely known, when partially-developed Su-8 is rinsed with
isopropanol, a white residue results. Is there anything else to rinse
the developer (besides water) that will stop the development and not
create the white residue? Is there a different developer that I can use
(i.e. ethyl lactate, diacetone alcohol) that I can rinse away with out
creating the residue?

Thank you,
Evan