Here's an article on using dry etch to pattern Cr on glass masks in the July
2001 issue of Semiconductor International.

URL:
http://www.reed-electronics.com/semiconductor/article/CA92550?pubdate=7%2F1%
2F2001

Cl2/O2/He gas is used. Low O2 concentration, low He flow and high pressure
is stated as the best regime for etching. They state that their results are
valid for both photoresist and ZEP e-beam resists. I'm sure there are more
recent articles available, but this might serve as a good starting point. -
Karthik



-----Original Message-----
From: Leyla Soleymani [mailto:l.soleymani@utoronto.ca]
Sent: Friday, March 16, 2007 12:10 AM
To: mems-talk@memsnet.org
Subject: [mems-talk] Using Chrome as etch mask

Hi,

I am using ebeam lithography to open holes in SiO2. PMMA is my resist
but it is not a good etch mask so I am using a layer of chrome on top
of the SiO2 and below PMMA as an etch mask. Does anyone know what
Chrome etchant I should use that does not attack PMMA or SiO2? Also
does buffered oxide etch attack Cr?