极紫外光刻系统物镜光学元件的支撑与分析

Objective optical mounts and analysis for EUVL

介绍了极紫外光刻系统物镜光学元件的支撑原理和支撑要求,分析了符合运动学支撑要求的物镜支撑结构和面形检测用支撑结构;针对支撑结构性能和支撑方案中关键问题进行了深入研究,并提出了相应的解决方案。最后建立了支撑结构的有限元模型,并在此基础上进行了重力场中的镜体变形分析和温度场作用下系统的热变形分析。分析结果表明,检测用支撑与实际用支撑两种结构在重力环境下支撑出的元件面形基本相同,面形相差0.0026nm(RMS);温控范围为0.05℃时,由机械结构热变形引起的镜体面形变化在0.001nm(RMS)量级。研究结果表明,运动学物镜元件支撑结构能够满足极紫外光刻系统对于物镜机械支撑结构的要求。

The principle and requirements of the optical mount of an Extreme Ultraviolet Lithography（EUVL） system are introduced, and the mount structures according with the kinematic coupling requirements used in an actual lithographic camera and used in an interferometer are analyzed. The mount performance and key problems in mount precept are studied, and the corresponding solutions are also brought forward. Finally, Finite Element Analysis（FEA） models for optical mounts are built up, and the figure changes in the gravitation field and thermal field are analyzed, respectively. The results indicate that the figures on the mount structures used in the camera and used in the interferometer are the same basically in gravitational field, and the difference of the figure is 0. 002 6 nm（RMS）. When the temperature has a change of 0. 05 ℃, the figure change of the structure is in the scale of 0. 001 nm（RMS）. The results show that the proposed kinematic mount structures can satisfy the mechanical requirements of mounts for EUVL systems.