At UC Berkeley, we routinely bonded semiconductor devices with glass frit in
the Glass Shop of Electrical Engineering Computer Sciences. The glass used
came from Owens Illinois in a "solder glass" development kit.  The glasses
were low-melting point, devitrifiable glasses.

In addition, we used glass frit from Vitta Corp. which had the frits on
a release paper with binder which made transfer uniform. I believe Vitta
Corp. is still in business. Any patents to Vitta were probably issued to
the President, Kitty Etra (sp?).

In addition to frit bonding. we did a fair amount of "field assisted bonding"
to silicon. The new moniker for this type of bonding is "annodic bonding".
We learned this technique circa 1979-1980 from the Nasa Technical Brief
Magazine.

Hard to believe a patent could be given for frit bonding chips!

                                        Bob Hamilton

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