Hi all

I am trying to etch SiO2 using PMMA as mask. I am using ICP RIE system for
plasma etching. My oxide layer is 250nm thick and the substrate is Si. PMMA
is 180nm thick. PMMA is not holding as a mask. I am not able to etch SiO2
with this thick PMMA. Can anyone suggest me how to etch SiO2 with this thick
PMMA as mask.

Thanks
Satish