Hello,

Me and my colleagues are trying to etch a 4 micron Pyrex layer with HF using
photoresist as a mask. We've seen delamination of the mask as seen by others. We
are currently using a Shipley 7 micron resist and 4:1 HF:H2O etch.

Any recommendations on the best resist and HF concentration to help us get the
whole film etched before delamination? Current the Pyrex is etching about
300A/s, so we'd need something that would last 2-3 minutes.

Thanks
-Mike