You could try this:
http://www.hexion.com/Products/TechnicalDataSheet.aspx?id=3942
(Epon 828)
When cured it has excellent chemical resistance (doesn't get removed by acetone
or resist stripper; I'm not sure how well it holds up in KOH though).
Dirk

-----Original Message-----
From: [email protected] [mailto:mems-talk-
[email protected]] On Behalf Of James Paul Grant
Sent: Wednesday, August 11, 2010 5:46 AM
To: [email protected]
Subject: [mems-talk] Spin on glue?

Hello all,

Does anyone know of a permanent spin on 'glue' that is temperature
stable (up to 140oC), KOH resistant, transparent and is not attached by
acetone?

It might help if I explain why I require such a glue:

I'd like to permanently bond a lithium niobate wafer to a slicon wafer.
The Lithium niobate wafer will then be lapped down to a thickness or
around 10 microns. Next I would like to etch a 1 mm by 1 mm window in
the silicon structure such that the 10 microns of lithium niobate is
essentially free standing.

Has anybody got any experience of such a technique?

Any comments are most welcome.

James