Hi, Terry,

I have used 49% HF (I am not sure, but someone called it pure HF), the
etching rate was quite unstable from 4 to 12um/min. Cr/Au is widely
used as a good mask for not too long etching time. You can also try to
use a silicon wafer as a hard mask if you want to do a long time
etching, for instance, etching through a whole glass wafer. You can
check following papers for more information about that:

Corman T, Enoksson P and Stemme G 1998 Deep wet etching of
borosilicate glass using an anodically bonded silicon substrate as
mask J. Micromech. Microeng. 8 84–7

Wang F, Li X, Guo N, Wang Y and Feng S 2006 A silicon cantilever probe
card with tip-to-pad electric feed-through and automatic isolation of
the metal coating J. Micromech. Microeng. 16 1215-20

Hope it helps. Good luck!


2009/5/1, Terry Zhu :
> To all,
>
> I am trying to develop a controlled glass etching using HF/H2O. Is there any
> of you who have experience about it? Any recomendations or comments about
> etchant composition, temperature, stiring condition, etch rate would be
> appreciated.
>
> Terry Z
>

Best regards,
Yours sincerely
Fei Wang
______________
Postdoctoral researcher, Dr
MIC - Department of Micro and Nanotechnology
Technical University of Denmark (DTU)
Building 344, 1st floor, Room no. 130
DK-2800, Kgs. Lyngby
Denmark
Tel:  +45 4525 6311
Fax:  +45 4588 7762
Email: fei.wang@nanotech.dtu.dk
       http://www.nanotech.dtu.dk