[mems-talk] RIE removal of S1818 photoresist

[Bob Henderson]

Mark:

I was surprised to hear your system etched Cr at all. Do you run other etch
processes in your system using fluorine or chlorine? If so you probably need
to clean the chamber to remove polymers containing residues other than pure
oxygen during ash. Your conditions look reasonable but using more rie power
at lower time might help as the Trion with ICP has been reported to generate
a lot of heat to the substrate or so I have heard. Bob Henderson

----- Original Message ----- 
From: "Curtis, Mark E." <Mark.E.Curtis-1 at ou.edu>
To: <mems-talk at memsnet.org>
Sent: Wednesday, January 16, 2008 8:44 AM
Subject: [mems-talk] RIE removal of S1818 photoresist


Hello all,

I&#8217;m using Shipley S1818 positive photoresist as a mask for wet-etching a 100
nm thick film of chromium.  After using a wet chemical photoresist stripper
there remains some photoresist residue on the surface of the chromium.  I&#8217;ve
attempt to use a Trion RIE to remove the photoresist residue with the
following etch parameters:
Gases/Flow Rate (O2/50 sccm),
Pressure (500 mTorr),
RIE Power (25 W), ICP Power (500 W), and
Time (30 min).

To my surprise, I found that not only did it remove the photoresist but also
the chromium.  Does anyone know of a good photoresist removal recipe for RIE
that will not etch chromium.  I have previously tried a shorter etch time
(~10 min) but it did not completely remove the photoresist residue.

Mark E. Curtis