+1 for RIE.

Fluorine containing gases are usually sufficient, but various metal
additives to glass slow down etching due to formation of nonvolatile
compounds. The best results are usually achieved with pure quartz glass
(fused silica). I would suggest to check the following references as a
starting point:

Journal of applied physics,  V. 92, p. 3624
Microelectronics engineering, V. 83 p. 1155
Sensors and Actuators A, V. 141 p. 677
SPIE V. 3680, p. 839
Vacuum V. 55, p. 191

Regards, Ivan

> -----Original Message-----
> From: Kuijpers, Peter [mailto:[email protected]]
> Sent: Wednesday, June 08, 2011 7:44 PM
> To: General MEMS discussion
> Subject: Re: [mems-talk] Controlled, slow and smooth glass etching
>
> Hi
>
> Try RIE etching.
>
> Regards,
>
> Peter Kuijpers