I do not believe Aqua Regia will attack chrome.  There are several chrome
etches available commercially (for example, Transene TFE and Transene TFD),
as well as Iodine based gold etches (for example, Transene TFA).  Transene
TFD and TFA are both photoresist compatible (i.e. they do not attack
photoresist).


David Nemeth
Senior Process Engineer
Sophia Wireless, Inc.
14225-C Sullyfield Circle
Chantilly, VA
Ph: (703) 961-9573 x206
Fax:(703) 961-9576

-----Original Message-----
From: mems-talk-admin@memsnet.org [mailto:mems-talk-admin@memsnet.org]On
Behalf Of apatel43
Sent: Friday, December 28, 2001 2:03 PM
To: mems-talk
Subject: [mems-talk] chromium etchant or gold etchant??


Hi,

I was wondering if someone maybe able to suggest what type of etchant i
should
use.  I have approximately 500 angstroms of Cr deposited, followed by 1500
angstroms of Au, finally with a 50 angstoms Cr layer on top.  I only
deposited
the top Cr layer so that polyimide would adhere well to the wafer.  I would
like to etch away thru all there layers.  I'm sure if i should use aqua
regia
to etch away at the gold or should i use some sort of a Cr etch? if so which
one could you suggest please...

Thanks,
Arti

Arti Patel
Research Assistant/Graduate Student
University of Illinois at Chicago
Department of Bioengineering
851 S. Morgan St. (m/c 063)
Chicago, IL 60607
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