Hi,

I am using ebeam lithography to open holes in SiO2. PMMA is my resist
but it is not a good etch mask so I am using a layer of chrome on top
of the SiO2 and below PMMA as an etch mask. Does anyone know what
Chrome etchant I should use that does not attack PMMA or SiO2? Also
does buffered oxide etch attack Cr? I would really appreciate some
help on this issue.

Regards,
Leyla Soleymani
University of Toronto