Hi all,

My SiO2 film thickness is about 200nm, and I want to open a hole with diameter
3um so that to pass through my electrode. I wonder when I etch it with CF4
plasma, will this have a bad aspect ratio? I mean probably only the center of
the hole is opened but the other area still has some SiO2 left?

BTW: how about CHF3 compared with CF4?

thank you in advance
shane