The metal leads in our design are made of a three metal stack of titanium,
nickel and gold.  These are evaporated onto 2µm oxide on a silicon
substrate.  This is the stack we've been using and we don't know the history
of where this was developed.  Recently, there appears to be cracks across
these leads resulting in open circuits.  On occasion, we also see adhesion
problems with gold to the nickel.  This raises a few questions:

1) Is there some inherent problems with this type of metal stack for our
leads?

2) What would an improved metal stack look like for metal leads in a MEMS
design?

Anthony Marrs