Hi,

I am working on electroplating silver on Au.

I tried a little bit on electroplating Au on Au seeding layer. It works pretty
good.
So I think you might need deposit a thin layer of Au as you seeding layer.
Actually, Cr or Ti have good adhesion ability if you worry about the adhesion
issue.
And I think you can improve the adhesion ability between your electroplated Au
and gold seeding layer by oxygen plasma etching to remove the contamination.
Another issue you mentioned is about surafce quality of plated gold. I think
that depends on your electroplating current density. Try lower current density
like 2mA/cm^2 and lower duty cycle and even reverse current for short time.

Hope you can work it out!

Huihang

> Date: Thu, 8 Jan 2009 12:03:38 +0530
> From: amrvlsi@gmail.com
> To: mems-talk@memsnet.org
> Subject: [mems-talk] Au electroplating on Al substrate
>
> Hi Denis Petrov,
>
>                I came across a similar situtation before and yes, Au
> was not electroplated on to the Aluminum substrate... in my
> experiment, a sulfite based Au plating solution was used, and even
> after 1 hour,   au was not plated on al substrate... i guess it may be
> becos of adhesion related issues, since Au was getting plated on Cr
> substrate (however, surafce quality of plated gold on Cr substrate was
> poor).... interested to know the exact reason, if anyone can explain..