Morning. Tired of starfalls an meteorites? Then read my question below.

We attach a 2x3" Alumina 0.25mm 99% on CuMo 1.0mm carrier by means of a
thermoplastic from one of the big US companies in the game. It's a
transfer, silverfilled product for automatic mounting. Max Tg approx. 75
degrees C. The substrates contains some chips that develop several watts
which has to be taken care of by the CuMo carrier. This is then mounted
on a aluminium structure.

Now, a pessimistic scientist thinks that, if vertically mounted, the
alumina substrate will glide slowly from its position, especially at max
operating temperature which may be 60 degrees C. The positioning is
important in this case because of bond wires. His argument is that the
thermoplastic is not crosslinked and stable as are thermosets.

Anyone out there, who is more optimistic?

                                  //Ingemar Hernefjord
                                 Ericsson Microwave Systems

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