Fabrication process of wobble motors with polysilicon anchoring bearing

Abstract

A simple fabrication process of wobble motors with a bearing anchored on a substrate by polysilicon has been developed. This process makes use of two LPCVD polysilicons, two LPCVD sacrificial layers SiO/sub 2/ and four photolithography steps. The rotor, stators and rotor/stator gap pattern definition is the first photolithography step and is performed over a flat surface. The rotor is in electrically contacts with the silicon substrate through the bearing. The rotor and the substrate is at the same electric potential, therefore rotor clamped is eliminated. The polysilicon which anchors the flange of micromotor is used stead of the SiO/sub 2/, the over etch time does not affect flange anchored on the substrate during release motor. The time releasing the motor is easily controlled. For 2.5 /spl mu/m-thick rotor/stater polysilicon films, minimum starting voltage 45 V, minimum operating voltage 25 V across 2.2 /spl mu/m rotor/stater gaps; maximum rotate velocity of the motor is 600 rpm, and varied with the exciting frequency continually.