Robert sounds to me like the Ti component of the film is oxidizing.
 Titanium oxidizes very easily. So if you evaporate the alloy for adhesion
(the Ti probably helps the adhesion to Si) then pure gold, you probably
will be able to plate the film.  Gary

Gary Hillman
Service Support Specialties, Inc.
9 Mars Court
PO Box 365
Montville, NJ 07045
973-263-0640
973-263-8888.



-----Original Message-----
From:   Robert Dean [SMTP:rdean@eng.auburn.edu]
Sent:   Wednesday, October 06, 2004 9:40 AM
To:     General MEMS discussion
Subject:        [mems-talk] problems with gold plating

Hello,

For a MEMS die bonding application, we need to plate 2um of Au onto a flat
silicon die cap that has TiAu (800A /1500A) E-beam deposited onto the SiO2
surface layer.  We are attempting to electroplate gold onto the entire
surface, i.e. no photoresist mold.  When we have the current set low, we
only get gold plated in a few islands.  When we increase the current until
we start getting uniform plating on the entire surface, we soon get one or
more black spots that grow in size and limit the plating.  Any suggestions?

Sincerely,

Robert Dean
Auburn University

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