Marvin Zai wrote:
>
> 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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1000A Al is way too thin for good thermosonic bonding.  You may want to
try thermocompression bonding.  Also, you may want to deposit an
adhesion layer prior to Al deposition, such as TiW.

Call me if you need more help.

Michael Young
ACSI
949-4538988
http://www.acsensor.com