光刻投影物镜元件面形精度为纳米量级,因此要求检测精度为纳米到亚纳米量级。为了完成光刻投影物镜的光学元件面形检测任务,提出了利用菲佐型干涉仪进行检测的方法。通过理论分析和计算模拟,分别对相移误差、参考面误差、探测器非线性误差等系统误差以及光源稳定性、环境控制等影响干涉仪测量精度的主要因素进行分析,给出了测量误差大小与干涉仪结构参数之间的关系。计算结果表明,限制菲佐干涉仪检测精度的主要因素是参考面的精度和环境的影响。针对以上结果给出了提高干涉仪测量精度与减小测量误差的方法,对高精度菲佐干涉仪的研制具有一定的参考价值。

The surface accuracy of lithography projection objectives is on nanometer scale,so the accuracy of the testing interferometer is also needed on nanometer to sub-nanometer scale. A method to test the optical surfaces of lithography projection objectives using Fizeau interferometer is proposed. Through theory analysis and computer simulation,the system errors caused by phase shifting,reference surface,and detector nonlinear are investigated. Other factors affecting measuring accuracy including light source instability and environmental control are also analyzed. The relationship between measurement errors and interferometer structure parameters is presented. Some methods and measures for improving accuracy and decreasing measurement errors are put forward. The results of the computation show that the accuracy of the interferometer is mainly limited by the accuracy of the reference surface and the stability of the environments. The results also have an important reference value for the design and manufacture of Fizeau interferometers.