KOH etching.

Jim McVittie mcvittie at snf.stanford.edu
Thu Oct 24 15:06:16 PDT 2002


Harshal,

I believe black wax will hold up to KOH. Here is a note from Mike Young
young at purdue.edu Purdue University ECE Dept.

"        We use Apiezon W, a black wax stick that softens around 100 C
and dissolves in most chlorinated solvents (TCE, TCA, DCA, etc.) It can
be mixed with a tiny bit of solvent to make a "goop" for applying to
the sample. When allowed to dry, it behaves like a nice thick coating of

resist, in terms of its resistance to wet etchants.

        Most US lab supply places can get it. If I recall, a place
called
Biddle is the "official" US distributor"

Physics stores carries black wax. It has been around for ever. I used it
in my 1st device
processing in 1966. As for a sovent, we do not allow TCA or TCE. in the
SNF lab except what is used during high temperature cleaning. I was
recently told that Physics stores also carries a safe sovent.

    Jim McVittie

It so
Harshal Surangalikar wrote:

> hello labmembers,
>
> i wanted to know if anybody has worked with a common
> plumber's grease kind of a material to mask a Si wafer
> to do single side etching in KOH, as i was interested
> by its chemically inert and temperature resistant
> (180C) properties. Although i will be using a fixture
> to do so, i just wanted to find out if there is an
> easy way to mask a side and have the etching done on
> the other.
>
> any feedback on use of black wax would also be
> helpful.
>
> thank  you.
>
> harshal.
>
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