I think you need to use ProTEK A2 with a resist. ProTEK A2 will will resist
49% HF for 60-90 minutes.

Do a google search for it.

Carlo Webster


On 16/11/07 7:57 pm, "Michael Larsson"  wrote:

> Hi Mike,
>
> Why use photoresist at all? You could just use a patterned layer of a
> Cr as the mask. In my experience, even buffered HF attacks
> photoresist. It may stick, but it will degrade the longer it remains
> in the etchant. Of course there is no harm in leaving the photoresist
> layer on the Cr, but as it absorbs liquid from the solution, the edges
> will soften, expand and warp, affecting the resolution of pattern
> transfer. Also, if you wet-etch the Cr, the Cr etchant will attack the
> photoresist so you will no longer have a pristine photoresist mask for
> the subsequent HF step.
>  Pattern the Cr, strip off the resist, run an O2 plasma descum, then
> etch the Pyrex in your chosen HF mixture. Good luck! :)