Pradeep
You have to apply AC pulse to remove the non
uniformity in the edges. This is the preferred method
bcos when you apply AC pulse,the edges are going to
have more C.d (when the si wafer become anode) and
then  at thee edges,dissolves at much faster rate.

SO you can try to do an AC deposition to get more
uniformity like in the same on/reverse period of
Pulse timings.

Bala.

--- Pradeep Dixit  wrote:

> Dear Iskandar,
>
> You can first deposit 50nm Cr + 200 nm gold layer on
> a silicon wafer and
> then deposit SU-8 and do the patterning. (you can
> also use copper, but it
> oxidizes fast, so gold  is a good choice). You can
> also do electroless
> plating for seed layer deposition. After
> patterning/sexposing, do a bit O2
> plasma to ensure that SU-8 is removed completly
> (5-10 min will be ok).
>
> For electroplating you can use pulse plating small
> current density ~ 5-10
> mA/cm2. Pulse on time - 0.9 s, pulse off period -
> 0.1s.
> I have seen from my experiments, that copper
> deposition is more at the edges
> than the center part. This non uniformity is due to
> localized current
> distribution at the corners. This non uniformity is
> an unsolved issue.
> Hope, this information will help.
>
> Thanks,
> Pradeep Dixit




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