How can I isotropically etch ~7.5 um of SiO2 with RIE only?

I'm looking to achieve maximum (but controllable) undercut with a PlasmaPro 80 RIE. I have tried the following recipe: 750 mTorr, 100 sccm SF6, 10 sccm O2, at 200W but the etch rate is very low...

28 February 2020 3,254 2 View