Hello mems community,
I am considering using ultrasonic bonding of Al/gold wire to platinum and
copper pads on a device and would appreciate any comments on the
following points:

1> The platinum pad (400 nm thick ) is deposited by evaporation on Si.
Since it is a part of an RTD sensor, using a metallic adhesion layer is
not advisable. Will low adhesion of Pt to Si be a problem for the
ultrasonic wire bonding process. If so, what is the minimum thickness of
the adhesion layer that i can get away with? Which is the preferred
material for the adhesion layer?

2> The copper pads will be deposited by evaporation on PYREX 7740 and the
Al wire will be bonded to the copper pads also by ultrasonic bonding. The
pad does not have to be copper if there are other metals which are
easier/preferable for wire bonding. Any suggestions?

Any comments from previous experiences on ultrasonic wire bonding to Pt
would be greatly appreciated.

Thank you
Ashish

===========================================================================
Ashish Pattekar                      | Off.      : 610-758-4668
Integrated Microchemical Systems Lab | Res.      : 610-954-9352
Department of Chemical Engineering   | Email     : asp2@lehigh.edu
Lehigh University,                   | Whome     : www.lehigh.edu/~asp2
Bethlehem, PA 18015                  |
http://www.lehigh.edu/~inmifuel/     |
===========================================================================