This paper reports on the design, fabrication and testing of an electrostatic micro-actuator for a magnetic Hard-Disk Drive (HDD) tracking servo. First, the design requirements for a micro-actuator in this application were investigated. These include high Z-directional stiffness, low in-plane stiffness, high structural aspect ratio, large output force, high area-efficiency, low cost, and mass-production by a boatch process. A novel area-efficient rotary micro-actuator design was devised, and micro-actuators were successfully fabricated using invvovative processing technologies such as high-aspect ratio polymer etching and thick metal electrodeposition. The fabricated micro-actuator has a structural thickness of 40 mu m with a minimum gap/structure width of approximately 2 mu m (aspect ratio of 10:1). The micro-actuator's frequency response was measured and it was confirmed that the micro-actuator has extremely clean resonse up to very high frequency region, and this fact enables the design of a servo system that exceeds a 5 kHz servo band-width, which is adequate to achieve a track density of more than 25 kilo-track-per-inch(kTPI).
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