光刻投影物镜的透镜支撑形式决定透镜的面形精度, 进而影响光学系统的成像质量。本设计为实现透镜面形精度优于 5 nm的 RMS值, 提出一种三点挠性主支撑和六点弹片辅助支撑的支撑形式。综合考虑透镜自重、夹持力和热载荷对透镜面形影响, 对支撑结构进行优化设计, 并进行了仿真分析。仿真后的面形结果为: 上表面面形 PV 21.7 nm, RMS 4.49 nm; 下表面面形 PV 81.3 nm, RMS 3.63 nm。仿真结果显示: 该种透镜的支撑结构可以满足光刻投影物镜的高精度面形指标要求。

The surface figure precision of lens is decided by the supporting form in lithography objective lens, which influences the performance of optics system further. In order to reach the requirement of lens figure precision, which is better than 5nm RMS, this article introduces a lens supporting structure. The structure includes three points main flexible supporting and six points aided spring supporting. Optimization and analysis to the structure has been done for considering the influence of gravity, clamping force and thermal on figure precision. The conclusion is that PV of upper surface figure is 21.7 nm, RMS is 4.49 nm, PV of lower surface figure is 81.3 nm and RMS is 3.63 nm. The supporting structure satisfies the requirement of high precision figure in lithography objective lens.