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