Hi Folks-

Does anyone have or know of any experience using silver thin films as masks
for etching silicon in any of the common anisotropic etch processes,
including KOH, TMAH, EDP or the Bosch/STS Deep RIE process?  [I need Ag on
my finished device for an unrelated reason, but it would be very helpful if
I could also use it as an etch mask.]

I don't believe silver will be dissolved in any of the above, but I'm not
sure how well thin films will hold up to extended etch times, temperatures,
concentrations, etc.  Does an oxide form during the etch?  Can it be removed
without damaging the remaining Ag or the Si?  I would be very interested in
any first hand observations or recommendations for using Ag (or Au), before
I try it myself.

I have spent much of the last two days searching for an answer to this
question with little luck.  Are there any good references that summarize
etch rates for potential masking materials in various etchants, particularly
metal masks?  One very nice table of several common ones was compiled by
Kirt Williams, and can be found on BSAC's web site:

http://www-bsac.eecs.berkeley.edu/db/etch.pdf

Unfortunately this doesn't have the specific info I need.  I would welcome
any other suggestions, and will gladly post a summary of any I receive.
Thanks for your time.

--
Marc Straub
Advanced Technology Development
Visteon Automotive Systems, Ford Motor Company
Dearborn, MI
mstraub1@visteon.com