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