Hello,  I am developing a MEMS sensor for harsh environments -- specifically
temperatures above 500C.  I'm looking for some resources to assist with our
electrical connections.  Currently, we are using microbrazing to attach a
Au-kovar ribbon to a pad.  The pad is 2 microns Ni with a half micron of Au
(with a Ti adhesion layer).  These pads are sputter-deposited.  The
microbrazing process bonds the wire well to the pad, but the pad separates
from the die often leaving a divot in the underlying silicon.  I am curious
if anyone has had similar situations and could suggest some alternate
metallurgies or processes that we could explore.

We're investigating electroplated pads now as a way to increase the
thickness (and hopefully remove some heat from our Si).

Steven