For explanations on etch mixtures, see the paper "Etch Rates for
Micromachining Processing" in JMEMS in Dec. 1996. It's in a few places
online.
    --Kirt Williams

----- Original Message -----
From: "Rupesh Sawant" 
To: "General MEMS discussion" 
Sent: Monday, March 27, 2006 9:06 AM
Subject: [mems-talk] BOE chemical composition


I am intending to etch mico-channels in glass by using BOE etchant. I
am little bit confused about the concentration of ammonium fluoride
used in the BOE. I have seen a ppt in which it is mentioned that 40%
ammonium fluoride had to be mixed with 48% HF in a desired ratio to
make a BOE solution. This ppt was mainly focussing on the etching of
silicon substrate. Do i need to follow the same concentration of NH4F
and HF for etching soda lime glass?