We report a recent breakthrough to control profile angle for SiO2 Deep Anisotropic Dry Etching (SDADE). Our study reveals that gas residence time is the key parameter to control profile angle. Moreover, we show that it is possible to control profile angle, SiO2 etch rate and SiO2 selectivity to Si mask independently. Finally, the optimized process has the following performances: angle profile: 89.8degrees, SiO2 etch rate: 500 nm / min, selectivity: 18:1.