Hi,

   Recently, I need to do some SiO2 etching but I had little experience about
this.

Basically, the SiO2 will be deposited on the TiO2 substrate first. The thickness
will be 50-100nm, which is adjustable. And I plan to use PMMA as the etching
mask. 100nm feature will be used. Hopefully the etching process can stop at the
TiO2 surface.

  Can you give me any advice about the wet chemical etching and RIE in this
situation??? Is common CF4 usable in this situation??

   Another question is that: can I use the UVN30 negative resist as a mask to
lift-off SiO2??

Thanks a lot

Xiaojing Zou