设计了一种非球面变焦光学系统, 解决了NA 1.35浸没式光刻照明技术中内外相干因子调节、能量利用率不足、模块使用寿命短的问题, 所设计的非球面变焦系统包括三个镜组、光阑面和像面.系统入瞳直径42 mm, 视场角1.89°, 实现焦距范围700 mm~1 830 mm, 变倍比2.61, 共使用七片透镜, 并在三个凹面表面采用了非球面设计.设计结果表明, 该系统成像质量优良, 点列图均方根直径均小于40 μm, 畸变均小于0.5%, 设计结果满足浸没式光刻照明系统的使用要求.

An aspherical zoom optical system is designed to solve the problems of adjustment of internal and external coherence factors, lack of energy utilization and short life of module of NA 1.35 immersion lithography system. This zoom optical system consists of both three lenses groups and the stop as well as the image plane. The system consists of 7 pieces of lenses with pupil diameter of 42 mm, view angle of 1.89°, which can realize the focal length of 700 mm~1 830 mm, zoom ratio of 2.16, and the three aspheric surfaces are all designed in concave surfaces of optical elements. The design results show that the system is with good imaging quality of RMS diameter less than 40 μm and distortion less than 0.5%, which can satisfy the usability requirements of the immersion lithography lighting system.