David,

Have you considered spray coating of your etched through wafers to overcome your
problem with wafer mounting and wax selection?

Check out a technical paper "Spray Coating for MEMS, NEMS and Micro Systems" at
http://www.evgroup.com/papers/memspapers.htm


Best regards,
Helge

-----Original Message-----
From: David Nemeth [mailto:[email protected]]
Sent: Tuesday, June 10, 2003 11:33 AM
To: [email protected]
Subject: [mems-talk] Wafer mounting


I am mounting a wafer with large holes in it onto another wafer in order to
spin resist on it.  The wafer is delicate, so I'm mounting it with black
wax.  However, I find the resist solvent (I'm using AZ4210) attacks the
blackwax a little, leaving a residue on the wafer.

Clear wax (I forget which kind) which dissolves in acetone is worse - it
dissolves in the photoresist solvent, and creates large, unpatternable areas
when I spin it.

Because of the fragility of the wafer, I need something that melts so I can
slide the wafer off easiliy, so using photoresist itself as an adhesive
won't work.

Has anyone else encountered this problem?  Does anyone know of a mounting
wax that is not attacked by the photoresist solvent?

David Nemeth
Senior Engineer
Sophia Wireless, Inc.
14225-C Sullyfield Circle
Chantilly, VA
Ph: (703) 961-9573 x206
Fax:(703) 961-9576


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