Hi Vijay,

I have etched >100µm of Si with Bosch DRIE simply using AZ4562 resist as a mask.

I believe the selectivity was about 1:65 (I used 6µm resist which was more than
enough to etch 150µm deep).  The feature definition is not as good as with SiO2
mask but you can always try a thinner resist layer.

Hope that helps,
Tim

-----Original Message-----
From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org] On
Behalf Of Vijay Rajaraman - EWI
Sent: 13 October 2009 15:25
To: mems-talk@memsnet.org
Subject: [mems-talk] Masking Material for DRIE

Hi All,

I want to etch 100 microns of Si using Bosch DRIE and I'm unable to use some
well known masking materials such as SiO2/ Al/Al2O3 for specific reasons.

So has anyone tried some other masking material than the above with reasonable
selectivity? For instance, I could think of a spin-on material such as resist or
SOG ?

Please share your experiences, either in the forum or in person (by e-mail). Any
tip(s)/suggestion(s) are appreciated.

Thanks,
Vijay