超精密光栅尺位移测量系统

Ultra-precision encoder system for displacement measurement

针对光刻机运动台位移测量需求,研究了利用二次衍射光干涉的对称式光栅尺位移测量系统。基于多普勒效应分析了光栅尺的位移测量原理,推导了光栅尺位移测量模型。设计了基于商用双频激光干涉仪的测量对比实验平台,开展了光栅尺位移测量系统原理验证实验、测量一致性实验和测量稳定性实验。实验结果分别表明：光栅尺位移测量系统原理正确;光栅尺和激光干涉仪位移测量系统间测量结果的差值小于16.67nm的置信度为0.95,具有良好测量一致性;光栅尺位移测量系统具有较好的抗干扰能力,鲁棒性强,能够满足光刻机运动台位移测量需求。

To meet the needs of the motion stage displacement measurement of the lithography machine,a kind of symmetrical grating displacement measurement system using the second-order diffracted light interference was researched.Based on the Doppler Effect,the displacement measurement principle of the grating was analyzed and the grating displacement measurement model was deduced. A measurement contrast experiment platform based on commercial dualfrequency laser interferometer was designed,and the principle verification experiment,measurement consistency experiment and measurement stability experiment of grating displacement measurement system were carried out. The experimental results show that the encoder displacement measuring system principle is correct. The confidence degree is 0. 95 when the deviation of two measurement systems is less than 16. 67 nm. The grating displacement measurement system has good environmental robustness and can meet the needs of the displacement measurement of the motion stage of the lithography machine.