In most case the deposition is geometry dependent since it is current
density dependent. Usually, current densities vary on resist coated
surfaces.

-----Original Message-----
From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org]
On Behalf Of Pradeep Dixit
Sent: Friday, July 03, 2009 12:25 PM
To: General MEMS discussion
Subject: [mems-talk] Metal electrodeposition rate

Hello All,

I would like to check some thing with you.

During through-resist electroplating, does metal deposition rate depend
upon the opening dimension of features?

I am trying to electroplating 8 um thick copper structures. resist mold is
12 um thick AZ9260. Seed layer is 30 nm TiW/ 300 nm Cu.

features are circular vias and have relatively large variation in diameter.
20 um vias are besides 100 um vias and 500 um vias.

Electroplating type: DC, 5 mA/cm2 current density

I want to know in advance:

will the electroplated thickness be same for all feautures (20 um, 100 um,
and 500 um) ?

OR

500 um diamter vias will be plated faster .

Your opinion will be appreciated.


Thanks,
Pradeep