I guess, your bonding interface had a lot of bubbles due to outgasing
of the resist. You don't tell us, whether you used positive or
negative photoresist. My advice: only use negative resist. The
positive one does outsgas to much. for former information see: F.
Niklaus , et al, "void-free full wafer adhesive bonding", ???. But I
don't have any idea about Au-bonds. Probably ouy should apply a
Ti-layer on top of it.

good luck!
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Joachim Oberhammer, Dipl.-Ing.

Royal Institute of Technology (KTH)   Phone:    +46/(0)8 790 6250
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Microsystem Technology (MST)          Mobile:   +46/(0)70 692 1858
                                       e-mail:   joachim.oberhammer@s3.kth.se
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