I feel your Al metal adhesion is not so good otherwise it would not have
come out from PZT. If  you can improve the adhesion I think you can work it
out. Also try to measure the Al thickness variation , it may not be 1micron
across the bond pad.

Prem

> -----Original Message-----
> From: Marvin Zai [SMTP:[email protected]]
> Sent: Friday, February 19, 1999 12:01 AM
> To:   [email protected]
> Subject:      Help needed for    -     Au wire bonding
>
> Dear MEMS experts,
>
> I would like to get some advice about Au wire bonding, as I am new to
>  the field of packaging.
>
> I wish to bond to Al pads on my chip, sputter-deposited onto PZT films
> (1 micron thick).  I have tried this, but have so far failed: either
> the first ball bonding does not stick to my Al film, or this film
> sticks to the Au wire and lifts off from the PZT film surface.  I have
> tested different power and time settings, but again, all in vain.
>
> I am using 1000A thick Al pads, and I am slightly reluctant to use a
> thicker film, since the whole structure is already rather stressed.
>
> Any comments, suggestions, and information, like the conventional film
> thickness range and materials used for top metallisation, are most
> welcome. I thank you all for your time.
>
> Marvin
>
>
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