I have found "Etching in Microsystem Technology" by Michael Köhler
(ISBN-13: 978-3527295616) to be a useful reference on etchants and
etch rates.
Vitaley

>
> ---------- Forwarded message ----------
> From: "Sven TS Holmström" 
> To: General MEMS discussion 
> Date: Tue, 26 Jan 2010 15:34:01 +0200
> Subject: [mems-talk] Etch Rates for Micromachining Processing
> Dear all MEMS-list subscribers,
>
> One very important piece of information while designing
> micro-fabrication flows is known etch-rates of your materials in
> different etchants. For several years I have made good use of  Etch
> Rates for Micromachining Processing, part I and II by Williams et. al
> to get a first idea of possibilities. These papers are certainly a
> good source, but they are not complete and they are by now a few years
> old.
>
> Does anyone here know about a more complete compilation of etch rates,
> or perhaps a smaller, but complimentary collection? I am interested in
> papers as well as books or other media, if available.