A method to reduce notching effect on the anchors of a micro-gyroscope

A novel three-step DRIE recipe with pulsed low frequency platen power of 380 KHz is proposed in this paper. The depassivation time/duty cycle and the etching time/duty cycle of the pulsed low frequency platen power in the etching step of Bosh process are experimentally studied through the silicon on glass process (SOG) of a micro-gyroscope. Experiments show that the recipe with a passivation time of 2s, a depassivation time/duty cycle of 2s/75% and a etching time/duty cycle of 4s/85% can effectively reduce the notching effect on the anchors of the gyroscope while keep good sidewall verticality and present no grass.