Do you have any way to block some of the current flow from the anodes to
your part via 'flagging' or changing of a 'baffle' in your plating cell?
You want to block some of the current flow from the OD of your anode.  You
can also get more deposition at the center relative to the outside by
placing your part closer to the anode if possible.  We can do 295um, +/-1um
or less, Ni plating over Photoresist glass masters but thickness is just an
A*hr adjust.  I'd think you would always want to rotate the part for
deposition uniformity.

Good luck.
Robert Bock
G3 Mastering Solutions Inc

> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of Denis Petrov
> Sent: Tuesday, November 18, 2008 3:42 AM
> To: General MEMS discussion
> Subject: [mems-talk] Cu electroplating uniformity problem
>
> Hello dear MEMS-Talk members!
>
> We are trying to electroplate 20-um thick copper over
> patterned 4-inch wafers.
> The problem is the uniformity of the Cu layer. If it is
> approx. 20 um in the middle of the wafer then we have
> something like 25 um at the edges.
>
> I found out that there is a device called an IBM Paddle Cell.
> Does anybody know anything about it? Is it of help in this
> case? Is there any other practical solution.
> We tried the rotating cathode method and we tried to agitate
> the solution with the rotating paddle. Did not help.
>
> Thank you!
>
> --
> M.Sc. Denis Petrov
> Ph.D. Student