Contact Dean Shoemaker at Carmel Chemicals.
He is the U.S. rep for EEJA (Elecroplating Engineers of Japan).
I've had them do a set of runs of 4-um-thick electroplated gold.
They were very willing to work with me.

Regarding the stress/peeling issue, you might use a thinner seed layer.
I have been using 100 A of chromium, figuring that was sufficiently thick
to get several layers of chromium oxide and chromium,
followed by 1000 A of gold. I had excellent adhesion and
didn't have any delamination problem.

    --Kirt Williams, Ph.D.     consultant

----- Original Message -----
From: David Nemeth 
To: 
Sent: Thursday, May 22, 2003 6:37 AM
Subject: [mems-talk] Electroplating/ thick metal deposition


> Hello,
>
> I am looking for a vendor with expertise in depositing thick layers (5
> microns) of gold on 4" and 6" silicon wafers.  The metal does not have  to
> be patterned, but the wafers have been etched all the way through with
KOH.
> The metal deposition has to be on both sides of the wafer.  The seed layer
,
> and any underlying dielectric layers, can be anything.
>
> We have tried electroplating in-house in the past, with a Chrome-Gold seed
> layer on top of bare silicon, but found that the adhesion suffered
greatly.
> The adhesion of the base film of 1000 A Chrome and 1000 A gold was
> excellent, and passed the tape test.  We played around with current
density
> and plating times, and occasionally got some good adhesion, but nothing
was
> consistent.  We've also had a vendor use e-beam evaporation, but again
with
> mixed results.  The films were stressed, which I fear may fundementally
> limit the adhesion, especially with larger wafers.
>
> We do not have the tools to closely monitor the state of the plating
> solution.  So the question I'd like to pose is this: does anyone know of a
> vendor that could deposit thick gold, preferably by electroplating, on 4"
> and 6" silicon wafers with consistently good adhesion?  The gold surface
> should be as smooth as possible (we'd like to do gold to gold
> thermocompression bonding on the wafers).  We're looking for a process we
> can ramp into production.
>
> Any help is appreciated.  Thanks!
>
>
> David Nemeth
> Senior Engineer
> Sophia Wireless, Inc.
> 14225-C Sullyfield Circle
> Chantilly, VA
> 703 961 9573 X206
>
>
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