We are trying to manually wire bond to thin (~.2 micron) Pt/Au on glass.
Although we get good bonds on test wafers at the time the metal is deposited,
the bonding is very unreliable after it has gone through more processing (i.e.
at wire pull test, the wire falls off, leaving the pad intact,& undamaged; or
the pull strength is low). The wafer sees anodic bonding conditions at one point
in our process sequence, and the sawing process can leave scratches on the pads
(the scratches do not penetrate the metal).

Going up in bonding energy, time and force is a concern, since the glass
sometimes forms fissures under the bonding area at more extreme bonding
conditions, and a subsequent wire pull creates a pull-out from the glass. It
does not seem to help anyway. These bonds have to survive a ~350C temperature
excursion, so a pull-out is a concern.

Has anyone ever dealt with a problem like this? Any advice or observations? You
input would be much appreciated!

Stan