http://www.transene.com/sio2.html

1. This etchant is designed to etch deposited oxides on silicon surfaces. These oxides are commonly grown in vapox silox or other LPCVD devices and differ radically from their thermally grown cousins in many important ways. One way is their etch rate another is their process utility. The deposited oxide is many times used as a passivation layer over a metallized silicon substrate. Silox Vapox Etchant III has been designed to optimize etching of a deposited oxide used as a passivation layer over an aluminum metallized silicon substrate. This etchant has been saturated with aluminum to minimize its attack on the metallized substrate.

2. Deposited Oxide (Vapox/Silox) Etch Rate:

4000 Å / minute @ 22 °C

3. This product contains:
Ammonium Fluoride
Glacial Acetic Acid
Aluminum corrosion inhibitor
Surfactant
DI Water

MSDS : http://www.utdallas.edu/research/cleanroom/safety/msds/documents/SILOXVAPOXIII_2_.pdf