Michael,

You might also want to explore the newest offerings from AZ.  I substituted
AZ50XT for AZ92xx in a thick film plating process at my former employer.
Certain offerings in the XT series are replacements for the AZ92xx series of
resists.

My process flow for this resist was:

33 µm coat AZ 50XT

110 °C soft bake for 4'

EBR

17 µm coat AZ 50XT

110 °C soft bake for 7'

Exposure

Develop in AZ421k


The purpose of the double coat and the intermediate EBR step was to eliminate
the edge bead on the wafer without eliminating edge coverage.  The follow on
step was thick Cu plating with a pin contact plater.  Copper would deposit in a
bad location if my edge protection was removed.


Best of luck,


- Garrett



-----Original Message-----
From: Haixin Zhu [mailto:[email protected]]
Sent: Friday, June 13, 2008 1:43 PM
To: General MEMS discussion
Subject: Re: [mems-talk] 20um features using AZP4620

Dear Chad,


U are right. Though I succeeded in making 38um thick pattern with 20um feature
size, there is still some problem with undercut of the pattern and bottom
residue. I will try AZ 9260, and hoping you can send me your processing traveler
so I can use as reference and start point.

Thanks

Michael