Image reversal and standard positive resist for lift off give 0.08
micron resolution and up to 40 microns thick resist.  Total uniformity
over the complete exposure area.  Most of the reversible resists and
negative lift off resists are a compromise that have problems.  Contact
me for lots of technical papers.  bmoffat@yieldengineering.com

-----Original Message-----
From: mems-talk-bounces+bmoffat=yieldengineering.com@memsnet.org
[mailto:mems-talk-bounces+bmoffat=yieldengineering.com@memsnet.org] On
Behalf Of David Casale
Sent: Monday, May 10, 2010 2:08 PM
To: mems-talk@memsnet.org
Subject: [mems-talk] Futurrex negative lift-off resists

I have recently been using NR9-1500PY resist from Futurrex for lift-off
metallization and wanted to see if anyone else has the same experience
that I am having with the resist. I am using a Bachur upright exposure
unit with near UV exposure, vacuum contact printing, and hotplates for
the PAB and PEB. I have been developing using full strength TMAH based
developer. My experience thus far is that the process latitude is very
small for getting the resist to work properly. I have noticed a
significant difference in the amount of undercut based on exposure and
develop times, and a also occasionally the resist just seems completely
over exposed and unable to develop at all. I also notice quite a bit of
variation in the amount of undercut over a 7"X7" area. I am just curious
if I am missing something in my process control that is common, or if
this is just the nature of using this type of LOR.

Sincerely,

David Casale
R&D Engineer
www.maxlevy.com  Max Levy Autograph 2710
Commerce Way Philadelphia, PA 19154 USA
tel: 215-842-3675