Application of a novel capacitive sensor in precise positioning systems

This paper presents a comb-finger capacitive displacement sensor used in nano-positioning system. The displacement sensor is designed to develop an integrated implementation platform and to achieve its closed-loop control. In the design, offset constant-tooth, combinations with S-type beams and flexible cantilevers have been adopted to enhance the position range and structure performance. Surface and bulk micromachining technology is employed to fabricate the sensor from a single crystal silicon wafer. Through testing of the nano-positioning stage, the capability of the sensor has been obtained. The results show that this method can achieve a detect range of 10 μm, with resolution of 5 nm.