Could you please send the link for your paper?

With regards,

Pramod Gupta
21084 Red Fir Court
Cupertino, CA 95014
Phone: (408) 253-1646

--- On Sun, 10/11/09, [email protected]  wrote:


From: [email protected] 
Subject: Re: [mems-talk] Removal of CMOS Pad Oxide
To: "General MEMS discussion" 
Date: Sunday, October 11, 2009, 6:49 PM


Hi:
We had a similar problem with post CMOS Processing, try zincation.  For
references check my paper in iop Nanotechnology June 2009,

Best,
-Mehmet R. Dokmeci

-----Original Message-----
From: Ken Townsend 
Date: Sat, 10 Oct 2009 18:39:53
To: 
Subject: [mems-talk] Removal of CMOS Pad Oxide

Hi everyone,

I am attempting to electroplate copper structures on to CMOS die.  Low
loss electrical contact must be made between the electroplated copper
and the CMOS top metal layer, an aluminum alloy, by way of openings in
the CMOS passivation layer.  These openings are created by the CMOS fab
(ie. they are standard pad openings).  Unfortunately, I am measuring
significantly more resistance between the CMOS Al and the Cu then
expected.  I believe the problem is incomplete removal of Al oxide.

Currently in my process I ion mill the CMOS (argon etch 20min at an
assumed 5nm/min) and then deposit Ti(10nm)/Cu(160nm) seed layers for
electroplating.  I then remove the sample from the chamber, pattern the
structures, and plate Cu(>5um).  Prior to plating I dip the sample in
H2SO4 for a few seconds to remove Cu oxide.

If anyone has worked with a similar process, I would greatly appreciate
suggestions concerning possible sources of the high loss and possible
ways to mitigate them.

Cheers,
Ken