Investigation on a Novel Dual-Grating Macro-Micro Driven High Speed Precision Positioning System for NEMS

Abstract

Microelectromechanical system (MEMS) is naturally continuing its downsizing into nanoelectromechanical system (NEMS), but at the same time it is indispensable in the package equipment used for nano-devices packaging in NEMS manufacture. A novel dual-grating macro-micro driven high speed precision XY-stage positioning system is presented in this paper. Combining macro with micro actuator, a system of large workspace and high speed with high resolution of motion is developed. Two linear voice coil motors (VCM) are used into the macro motion, and two piezoelectric (PZT) driven micro stages of high frequency are mounted on each motor to compensate the position error. A novel elastic decoupling mechanism is used in the stage to avoid the moving gap. The coarse micron grating and the fine nanometer grating are integrated into the closed-loop feedback, which is used to measure the position of the output end of macro stage and micro stage. Adopting a complex method of the position of coarse/fine gratings, the nano-positioning with high speed of XY-stage is achieved. By using the mechanical dynamic simulation and finite element analysis (FEA) method, the decoupling mechanism and the micro mechanism are optimized, and the dynamic characteristics of the stage are investigated, which is based on the rigid-flexible dynamic analysis of mechanical system. The simulation results show that this new configuration allows a workspace of 25mmtimes25mm and an acceleration exceeding 100m/s2 with a resolution of motion better than 10nm