If you are flexible with what kind of glass you use, you can use a white
crown glass with a standard masking using chromium and photoresist. I've
etched through 700 µm thick wafers easily and you can probably go much
further. The thing is that the white crown etches around five times
faster than borosilicate and your masking layer will then last a lot
longer.

We are using a glass etching solution containing HF:HNO3:H20 (100:28:72)
which I guess is a bit less aggressive than the concentrated HF.

/Mikael

Moshe wrote:
> Hello
>
> I am looking for a way to make holes 1 mm diameter in glass.
> I did gold mask on the glass and  tried polysilicon as a mask too but the HF
stripped the masks.
>
> Do you have a solution for the mask ?