电子束曝光机工件台结构的设计研究

Design and Study of the Stage Structure of the Electron Beam Exposure System

根据激光定位光栅扫描电子束曝光机工件台具有的特点，设计了ｘ向用静压气浮导轨结构，实现快速扫描；ｙ向采用机械滚珠导轨，满足间歇步进运动，即走一步、停一段时间再走一步、为保证在高速运动下的稳定性，将机械驱动系统、激光测量和计算机组成一个闭环控制系统，利用计算机不断采样叠代，选择合适的校正系数适时校正，实现了快速运动精确达到预定位置。采用双频激光高精度测量定位，从误差分析出发，对结构进行了改善，保证了最终精度。

This paper discribes the structural features of the Laser interferoinetric positioning stage satisfying specific needs of raster scanning E-beam exposure system. An aerostatic air bearing is designed to realize the high speed scanning motion of the stage in x direction. A ball bearing is designed to realize the stepping motion of the stage in y derection. To ensure the stability and positioning accuracy under high speed motion, a closed-loop control system consisting of a mechanical system, laser interferometer and computer is developed.The computer is used for selecting proper correetive factor by sampling and reiterative method to realize real-time correction of linear system.High accuracy in the stage positoning measurement is obtained by utilizing Doppler effect of double frequency laser interferometry. Accurate position can be reached in a predetermined area. Error analysis of stage structure design ensures the final accuracy of the stage.