Nathan,

You are correct that there are much simpler ways to perform isotropic
etching in glass and quartz, but the problem is that companies that have
addressed and solved this issue are not likely to disclose their process
methods.  There are companies that offer small volume custom chip
fabrication at reasonable prices.  Obviously this is not an option for
you if you want to build chips hands on.

Mac McReynolds
Caliper Life Sciences

-----Original Message-----
From: mems-talk-bounces@memsnet.org
[mailto:mems-talk-bounces@memsnet.org] On Behalf Of Nathan McCorkle
Sent: Tuesday, November 03, 2009 1:52 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