For steep sidewalls, you can also use laser drilling or FIB milling.  There
are several companies that will do this on an outsource basis.

-----Original Message-----
From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org]
On Behalf Of Steven Yang
Sent: Wednesday, August 01, 2007 6:05 AM
To: mems-talk@memsnet.org
Subject: [mems-talk] Re: Any suggestions on through holes on Glass pyrex
7740

The thickness of glass wafer is 500 micron. I am wondering how much
will the aspect ratio if using HF etching?