Plusing, current density matrix is the right direction. Try electrode
distance and shape as well.
Shay

-----Original Message-----
From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org]
On Behalf Of pralston@vt.edu
Sent: Friday, May 08, 2009 6:32 PM
To: mems-talk@memsnet.org
Subject: [mems-talk] Gold Post Electroplating; Posts are Hollow

I am trying to electroplate gold posts that are 50-100 microns wide using a
KMPR mold that is about 60-70 microns thick.  Using TG-25 electroplating
solution I have tried to electroplate at various current densities (1-10
mA/cm2) and have tried DC, pulsed, and reverse pulsed plating.  I
consistently get the same results; "crown shaped" pins where very little
gold is plated in the center of the KMPR hole and the plating on the sides
of the holes is much higher.

I have tried to ultrasonicate the chip in water before performing the
plating to remove any air bubbles that remain in the KMPR holes.  This seems
to improve the quality of the plating (the plating looks more yellow in
color), but the pins are still hollow. Perhaps I am not removing all the air
from the holes?

Anyone run into this problem?  Any suggestions for a solution??

Thank you,
Parrish