Thanks all. But there are still something I cannot
understand. Why using the pulse plating will get the reverse
trend? What is the mechanism behind? Is there any webpage
explaining this interesting issue?

> If you are plating from a cyanide bath, you can improve
> the uniformity by pulse plating. You can use something
> with < 50% duty cycle (4ms on, 10 ms off). I do
> pulseplating on a 4" * 4" wafer with a current density
> less than 1.5 mA/cm2 and I get pretty good uniformity.(3.2
> um center and 3 on the edge). You will notice that the
> thickness trend gets reversed with pulse plating because
> the polarization increases in the high current density
> areas thus counteracting deposition rate variation.
> Lakshmi Namburi.
> Process Engineer.
> Teravicta Technologies Inc.,
> Austin, TX-78758
> [email protected]
>
>
>
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