Hi Adriele,

Photoresist peeling is often a problem with unbuffered hydrofluoric acid,
although I have usually only seen this associated with the concentrated (i.e.
49%) solution. However, hydrofluoric acid buffered with ammonium fluoride (i.e.
BHF) tends to perform better in this regard.

A very convenient reference for material etch rates can be found as follows:

Kirt R. Williams and Richard S. Muller
"Etch Rates for Micromachining Processing"
Journal of Microelectromechanical Systems
Vol. 5, No. 4, Dec. 1996

Best of luck with your work!

-Craig McGray
 Dartmouth College



mems-talk-request@memsnet.org wrote:

> Reply-To: "Adriele" 
> From: "Adriele" 
> To: 
> Date: Mon, 13 Aug 2001 17:45:44 +0100
> Subject: [mems-talk] Glass etching
>
> I'm having problem on etching a normal borosilicate glass with HF(conc. =
> 4:1 not buffered).=20
> The etching process comes irregular and strip off the resist after =
> 25mins I run the process.=20
> Is there anyone that have a better idea on how to etch it? Someone =
> suggest to etch the glass using FIB or Ion beam etching technique. Is =
> there anyone that have experience on that.
>
> Any help  would be appreciated.
>
> Thanks=20
>
> Adriele