Dear MEMS society,
Here are the replies I got untill now for recipes for isotropic glass etching:

REQUEST:

>Has any of you heard of /experience with Deep Reactive Ion Etching of
>glass/pyrex/quartz substrates ?
>We want to etch in the range 20-100 5m with vertical sidewalls.
>Which mask materials should be used ?
>Any comments and/or etch recipes are welcome !

ANSWERS:

Yes,  try Norsam, www.Norsam.com.  You can use photoresist as mask material.
Regards,
Chia-Lun Tsai, Ph.D.
   Research Scientist
   Integrated Sensing Systems, Inc.
   387 Airport Industrial Dr.
   Ypsilanti, MI 48198
   Phone: (734) 547-9896, Ext.115
   Fax: (734) 547-9964
   Email: chialun@mems-issys.com
   http://www.mems-issys.com/



I did some research on this and found from STS that the DRIE machine they
make is not capable of silica DRIE.
Justin Mansell  |       "Only a risk tests the reality of a belief"
Ginzton Laboratory      |                       - C. S. Lewis
445 Via Palou St.       |
Stanford, CA 94305      |



Please check www.triontech.com. Depending on thickness we may be able to offer
solution to you. Probably need He cooling for backside of wafer and proceed
with rather slow etch to keep temp cool. Bob Henderson 602-968-8818



CHF3 is often used for etching SiO2.
I have had good results using both nickel and chromium as masking materials
for deep plasma etch applications.  Aluminum can also be used but, but
unless it is sufficiently thick you may sputter it away before your etch is
complete.



>>RIE  parameters for pyrex 7740 glas:
>>7 sccm O2
>>72 sccm SF6
>>pressure: 60 milliTorr
>>Power: 150 W
>etch speed: 15 µm in 6 hours (might be higher using more power). They claim
>anisotropic...
>problem: it gives "teflon" on the chamber walls, which peel off. Quite
>contaminating...