KOH attacks SiO2, but TMAH attacks it only a very small amount.  I've used 1
micron thermal oxide as a masking layer on a 500 micron wafer.  The only
problem I've encountered is that sometimes the undercut SiO2 mask breaks
from internal stresses.

David Nemeth
Senior Engineer
Sophia Wireless, Inc.
14225-C Sullyfield Circle
Chantilly, VA

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of
Byunghoon Bae
Sent: Friday, August 08, 2003 5:58 AM
To: [email protected]
Cc: [email protected]
Subject: [mems-talk] SiO2 mask


Dear community

I'd like to use SiO2 as an wet etch mask in TMAH, but TMAH does etch SiO2.
What I want to do is etch whole Si except membrane which is spun on Si. So,
much thick SiO2 is needed.

1) How much %wt TMAH is preferred? Only TMAH or mix with other chemicals?

2) How much thickness of SiO2 is needed to persist in TMAH during Si
etching?

3) Etch time and temperature of TMAH which is corresponding to 2)?



Sincerely,

---------------------------------------------------------
Byunghoon Bae

Visiting scholar
Mechanical & Industrial Engineering
Univesity of Illinois at Urbana-Champaign
26 MEB MC-244
1206 W. Green St. Urbana, IL 61801
Tel: 1-217-244-7301, Fax: 1-217-244-6534
E-mail: [email protected]

Ph. D. candidate
Dept. of Mechatronics
Kwangju Inst. of Science and Technology(K-JIST)

¸¶À½¼ö·Ãȸ ȸ¿ø
Member of mind(maum) meditation center

-¸¶À½Àº Çϳª, ¸¶À½Àº ¸ðµç °Í
Âü³ª¸¦ ã¾Æ, ¼ø¸®ÀÇ ˜®À»-
-Mind is one, mind is everything
Taking the path toward the truthful life-

Mind meditation center:
Korean: http://www.maum.org
English: http://211.47.66.148/eng/
Japanese: http://www.kokolo.org


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