光学学报, 2014, 34 (8): 0811001, 网络出版: 2014-07-09
光刻机投影物镜热像差主动补偿方法研究
Active Compensation of Thermal Aberrations in Lithographic Projection Lens
成像系统 热像差 主动补偿 光刻机 投影物镜 imaging systems thermal aberration active compensation lighography projection lens
摘要
非均匀照明导致的热像差是光刻机投影物镜工作过程中成像性能劣化的主要因素,对其补偿是必要的。针对物镜热像差的补偿问题,提出了分区式加热补偿镜的方案,利用玻璃材料折射率随温度变化的特点,采用电薄膜加热器在镜片的周围加热,从而产生可控的波前变化以补偿物镜由照明引起的热像差。建立了补偿方案的理论模型,并以一片平板透镜为对象开展了实验验证,实验结果表明,补偿前后镜片的波前由12.52 nm[均方根(RMS)]变化至2.95 nm(RMS),表明该补偿方案是可行、有效的。
Abstract
Thermal aberrations caused by absorption of laser energy are the key factors that make the image performance of lithographic projection lens degrade. Compensation of thermal aberrations is inevitable. A new compensation method of wavefront aberrations by controllable heating of a lens using film heater matrix is presented. For the refractive index of glass changes with temperature, heating on the periphery of a lens will produce a controlled wavefront change that can compensate for the system′s thermal aberrations. The feasibility of the compensation method is validated by compensating the wavefront of a plate lens. The results show that the wavefront of lens changes from 12.52 nm root mean square (RMS) to 2.95 nm (RMS) after compensation, indicating that the compensation method is effective and feasible.
陈华, 苏东奇, 隋永新, 章明朝, 田伟, 杨怀江, 张巍. 光刻机投影物镜热像差主动补偿方法研究[J]. 光学学报, 2014, 34(8): 0811001. Chen Hua, Su Dongqi, Sui Yongxin, Zhang Mingchao, Tian Wei, Yang Huaijiang, Zhang Wei. Active Compensation of Thermal Aberrations in Lithographic Projection Lens[J]. Acta Optica Sinica, 2014, 34(8): 0811001.