365 nm光刻照明系统中变焦系统的设计及公差分析

Design and tolerance analysis of the zoom system in 365 nm UV lithography illumination system

照明系统是投影光刻曝光光学系统的重要组成部分,它实现的功能是为掩模面提供高均匀性照明、控制曝光剂量以及不同照明模式。变焦系统作为光刻照明系统的重要组成部分,对提高整个光刻机的性能起着至关重要的作用。文中针对紫外光刻照明系统的特点,采用CODE V软件完成了波长365 nm,入瞳直径Φ33 mm,像方远心度≤10 mrad,畸变≤±2%近紫外光刻照明系统中变焦系统的设计,分析了变焦系统的误差源对系统光瞳性能的影响,结合变焦系统的设计方案和实际加工能力,给出单面厚度公差需小于20μm,动件移动精度小于0.5 nm,各透镜偏心公差小于0.02 mm,各透镜倾斜公差控制在1′之内。制定公差合理、可行,满足了紫外光刻照明系统高均匀性、高能量利用率的要求。

The illumination system is an important part of the projection lithography exposure optical system.Its function is to provide high uniformity illumination and control the exposure dose and different illumination modes for the mask surface.As an important part of the lithography lighting system,the zoom system plays a vital role in improving the performance of the entire lithography machine.According to the characteristics of the ultraviolet lithography illumination system,this paper uses CODE V software to complete the design of the zoom system in the near ultraviolet lithography illumination system with a wavelength of 365 nm,an entrance pupil diameter ofΦ33 mm,an image telecentricity ≤10 mrad,and a distortion ≤±2%.The effect of the error source of the zoom system on the pupil performance of the system is analyzed,combined with the design scheme of the zoom system and the actual processing capability,gives a single-sided thickness tolerance of less than 20 μm,a moving part movement accuracy of less than 0.5 nm,and an eccentric tolerance of less than 0.02 mm for each lens.The tilt tolerance of each lens is controlled within 1 ′.The tolerances are reasonable and feasible,and meet the requirements of high uniformity and high energy utilization of the UV lithography illumination system.