I think you will need a specialty chemical to do adhesion promotion. One
end of the molecule will need to bond to the silicon and the other end
will need to be a fluorocarbon chain. Something like
Hexamethyldisilizane with one of the methyls a fluorocarbon chain. You
probably need to have a pretreatement of sulfuric peroxide to populate
the silicon surface with OH groups.

The adhesion molecule will bind to the subtrate and then form a
compatible surface for the Teflon. You might want to get very exotic and
have some reactive groups on the fluorocarbon end also. So you do the
prime at one temperature and then bake the spun on Teflon at a higher
temperature to activate the groups. I am not sure what those groups
would be that would react with Teflon. Perhaps a R-Mg-R entity. A
Grignard reagent type group. The problem is that they decompose readily.


I know others have tried, but they abandoned efforts to do it. So I
think you will be a pioneer in this.

Ed

-----Original Message-----
From: mems-talk-bounces@memsnet.org
[mailto:mems-talk-bounces@memsnet.org] On Behalf Of Teimour Maleki
Sent: Sunday, April 20, 2008 10:35 PM
To: 'General MEMS discussion'
Subject: [mems-talk] Teflon Paterning

Dear all,
 I am trying to pattern a thin film of Teflon on silicon substrate. I
tried argon plasma activation, it seems fine, but I have problem with
adhesion of Teflon to silicon. When I do post processing, it will pill
of. Any comments on this will be appreciated very much.
Thanks,
-Teimour