Without having any direct experience with AZ9260 it sounds like one of
two things has happened, if I knew how big 'big' is then I'd be able to
give you better info.  One: you've reached the solvation limit of the
thinner.  You may try heating under reflux to eliminate the 'beads'
though you'd probably have to spin at temperature too.  Two: there are
intrinsically high molecular weight polymers in the AZ9260, you will
only be able to eliminate these through submicron filtration.  Finally
remember that there is a thickness-spin speed relationship (buy a faster
spin coater).

Good luck,
Matt

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Z. Jiang
Sent: Monday, October 18, 2004 8:29 AM
To: [email protected]
Subject: Spam:[mems-talk] how to spincoat a 50nm thin uniform film of
AZ9260?

hi,

   I need to spin-coat a layer of very thin (~50nm) AZ9260 photoresist.
Normally AZ9260 is for thickness range 4um to 25um. By adding AZEBR
thinner
to a certain ratio (from 1:5 to 1:50), it can be diluted and spin-coated
to
sub-micron thickness. However, the film formed by the diluted solution
will
always contain some big black polymer beads which seriously harm the
quality of the film. Does anyone have similar experience and can tell a
little bit information on how to avoid this problem? Thanks a lot.

   Jiang
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