>From my own experience photoresist is not that good. The solvent in the
photoresist is hardly evaporated through the
thin 4" layer between the two wavers. If you give only few drops you may have no
homogeneous layer and even air
included. This makes thermal contact very bad and may lead to crack the wafer if
you etch down to very thin membranes.

I have quiet good experience with white wax from Aremco company:

http://www.aremco.com/a9.html
Crystalbond(tm) 555 & 555-HMP
Low melting point adhesive systems for moderate-stress machining processes.
Transparent in thin cross-sections. Soluble in hot water.

On the hot plate, using a alu foil, I heat up the device or the support wafer to
66°C and bring the white wax onto the wafer
then I put the second wafer on top of the first and take the alu foil with the
wafersandwich from the hot plate. Applying some
pressure and takeing care to good wafer alignment I wait until the white wax is
hard. Then I clean the edges avoiding contamination
of the DRIE chuck.
After the etch the white wax is removed by warm water.

Greetings
Stefan



-----Original Message-----
From: [email protected] [mailto:mems-talk-
[email protected]] On Behalf Of Burkhard Volland
Sent: Donnerstag, 8. April 2004 09:01
To: General MEMS discussion
Subject: Re: [mems-talk] Temporary Bonding for DRIE


Would photoresist be an option? Three or 4 small drops of PR would be enough to
stick the devive wafer to the carrier. PR is compatible with DRIE, and removable
by Azeton. As a disadvantage, temperature control of the device wafer during
DRIE may be an issue.

Best regards

Burkhard
-----Ursprüngliche Nachricht-----
Von: Rahul Agarwal 
An: [email protected] 
Datum: Mittwoch, 7. April 2004 19:03
Betreff: [mems-talk] Temporary Bonding for DRIE


>To do the DRIE I have to bond the wafer from the back
>side otherwise the devices will just fall off, which I can't afford. So
>I am looking for some material which I can use to temporary bond the
>device wafer to a handle wafer, do the DRIE and then take the handle
>wafer off, after I have done the final bonding of my devices from the
>top side (after DRIE).


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