---- Original Message -----
From: "nupur b" 
To: 
Sent: Thursday, July 27, 2006 11:01 AM
Subject: [mems-talk] Au plating
HI Everybody,

I'm trying to electroplate Au on the substrate. I have a seed layer of
gold on the substrate on Sio2. I'm using 10mA for a 1X1 cm sample.
the gold solution is Aurofab BP and it heated and stirred during the
process. My problem is the surface looks very rough and somtimes the PR is
removed. I would really like some help.
Thanks,
Nupur
__________________
Nupur,
Most Au plating solutions are designed to plate with the current density
(CD) of app. 5 mA/cm2. In addition a good and uniform mixing is a
prerequisit for an acceptable deposit (e.g. stirring at the bottom of the
beaker does little to provide adequate exchange of matter at the
wafer/liquid interface). If you were plating 1 cm2 of non-patterned
substrate your CD was excessive especially if the mixing was inadequate.
If the surface was patterned the actual CD was even higher. In addition,
excess current density is causing gas (H2) evolution from the surface. This
combined with pH rise will cause damage to the resist and peeling effect.
Thus, lower the CD, improve mixing and make sure your solution pH is near
neutral.

Igor Kadija
201-670-8397
 www.fibrotools.com