Hi Jiaxing,  I use CH4:H2 RIE processes on a daily basis and routinely use
various photoresist, SiO2, or Nitride.  I have never used it with PMMA or in
etching II/VI materials.  The nature of CH4:H2 etch is that it typically
forms a polymer on all surfaces except what you are etching. My guess is
that PMMA is fine.

Good luck,

Scott



-----Original Message-----
From: jiaxing Yang [mailto:[email protected]]
Sent: Friday, March 24, 2006 9:48 AM
To: [email protected]
Subject: [mems-talk] Question about the mask for RIE etching


I am thinking about RIE dry etching of my II-VI
semiconductors(ZnSe and ZnCdSe based), the gas mixture
from literature I found is CH4:H2. My question is, can
I use PMMA as mask? it looks like some photoresis or
metals work.
Any one hes the idea of the mask choosing?