Magnetic microactuation of torsional polysilicon structures

Abstract

A microactuator technology utilizing magnetic thin films and polysilicon flexures in applied to torsional microstructures. These structures are constructed in a batch-fabrication process that combines electroplating with conventional IC-lithography, materials, and equipment. A microactuated mirror made from a 430 μm × 130 μm × 15 μm nickel-iron plate attached to a pair of 400 μm × 2.2 μm × 2.2 μm polysilicon torsional beams has been rotated more than 90° out of the plane of the wafer and actuated with a torque greater than 3.0 nN m. The torsional flexure structure constrains motion to rotation about a single axis, which can be an advantage for a number of microphonic applications (e.g., beam chopping, scanning, and steering).