I am somewhat surprised to hear that you can't just etch with Buffered
Oxide Etch with 13:2 ratio. Make sure your glass is very clean, use
vapor prime and thick positive resist. Bake it well so HF can't
penetrate the resist. Don't use HF, but use BOE.

Ed

-----Original Message-----
From: mems-talk-bounces@memsnet.org
[mailto:mems-talk-bounces@memsnet.org] On Behalf Of Nathan McCorkle
Sent: Tuesday, November 03, 2009 3:52 PM
To: mems-talk
Subject: [mems-talk] Looking for a way to do deep etch in glass (25uM)


I am currently working with lexan (polycarbonate) and am experiencing
optical blurring when I use O2 plasma etch for too long, as well as
warping. I have decreased power and time to alleviate this problem, but
it takes many more runs to achieve the 20 - 30 micron etches that I
desire.

I asked an advisor about switching to glass, maybe a quartz or
borosilicate, and he said that I would need a gold hard mask to get
around having mask lift off during etch. I feel like there should be
some way to get a nice isotropic etch with a glass, using the current
lab equipment that we have.

Any ideas?

Nathan McCorkle