Michael's statement requires a slight correction: Pure TMAH attacks
Al very rapidly, it is doped (with 0.5% Silicon) TMAH that doesn't.
I have this from literature, but cannot find the reference at the
moment.

Greetings,
        Frank Berauer
        Senior R&D Engineer
        Hewlett-Packard Singapore


-----Original Message-----
From: Michael Pedersen [mailto:[email protected]]
Sent: 12 December 2001 23:32
To: [email protected]
Subject: Re: [mems-talk] How to protect Aluminium thin film from KOH
solution


Hi Soumen,
You may want to consider using TMAH for the silicon etching. This
etchant is known to have limited effect on aluminum.

-Mike Pedersen

Soumen Das wrote:

> Hi all
> We are working on fabrication of various MEMS devices.We are facing some
> problem regarding how to protect the aluminium layer while doing the
silicon
> etching in KOH solution. Is there any chemical (just like photoresist)
which
> can be covered on aluminium layer and also can be patterned so that while
> dipping the silicon wafer in KOH solution the chemical layer will not be
> attacked by KOH solution and it can be used as protecting layer for
underneath
> material.
> Any suggestions will be highly appreciated.
> Bye
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