中国激光, 2018, 45 (5): 0504002, 网络出版: 2018-05-02
抑制零级串扰的光栅横向剪切干涉测量 下载: 841次
Grating Lateral Shearing Interferometry for Suppressing Zero-Order Crosstalk
摘要
为降低传统光栅横向剪切干涉仪中双方孔空间滤波器带来的加工和装调难度, 设计了一种基于9步式零级相位误差标定的光栅横向剪切干涉测量方法, 只需采用可变空间滤波器即可抑制零级串扰对相移相位复原的影响。针对数值孔径为0.125的投影光刻物镜, 完成了参数设计和原理验证系统的搭建。通过剪切相位复原和波前重构, 实现了该物镜的波像差检测。结果表明:其波像差小于20.32 nm。最后对该光栅横向剪切干涉仪进行重复精度实验, 其重复精度的方均根值为0.1303 nm, 系统性能良好。
Abstract
In order to reduce the difficulties in manufacture and assembly of the spatial filter with two square windows in image plane, we propose a grating lateral shearing interferometry based on a nine step phase shifting method, which is used to calibrate the zero-order phase error. The zero-order crosstalk could be eliminated only by a variable space filter. The parameters are designed and the principle verification system is completed for a projection lithography lens with numerical aperture of 0.125. Then the wavefront aberration measurement of this lens is achieved by the restoration of shearing phase and the reconstruction of wavefront. The results show that the wavefront aberration is less than 20.32 nm. The repeatability precision of the grating lateral shearing interferometer is measured. The root-mean-square value of the repeatability precision is 0.1303 nm, which shows the performance of this system is well.
方超, 向阳, 齐克奇. 抑制零级串扰的光栅横向剪切干涉测量[J]. 中国激光, 2018, 45(5): 0504002. Fang Chao, Xiang Yang, Qi Keqi. Grating Lateral Shearing Interferometry for Suppressing Zero-Order Crosstalk[J]. Chinese Journal of Lasers, 2018, 45(5): 0504002.