Single crystal silicon rotary microactuator for hard disk drive

Abstract

Abstract A single crystal silicon rotary microactuator for hard disk drives (HDD) is described in this paper. The microactuator is mounted between the slider and suspension and drives the slider on which a magnetic head element is attached. The microactuator has electrically isolated microstructures with an aspect ratio 20:1 directly processed from a single crystal silicon substrate. It consists of a stator attached to the silicon substrate by bus bar, and a movable rotor connected to an anchored central column via spring beams. Both the stator and the rotor are suspended from the silicon substrate. When a voltage is applied to the actuator, the microactuator will drive the head to move in tracking direction by the rotational motion of the rotor. The microactuator prototype with overall dimensions 1.4 mm ×1.4 mm ×0.18 mm has been successfully fabricated. The results of finite element method (FEM) simulation demonstrate that the microactuator has a better dynamic performance in a Head Gimbal Assembly (HGA) for hard disk drives. Experiments show that ±0.6 μm equivalent displacement of the head element in tracking direction is achieved under the driving voltage 20 V. The frequency response testing results of the microactuator bonded with a slider indicate that the microactuator is feasible to operate as a fine actuator in HDD.