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12.52nm[均方根(RMS)]变化至2.95nm(RMS),表明该补偿方案是可行、有效的。
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.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2014年第8期131-134,共4页
Acta Optica Sinica
基金
国家重大科技专项基金
关键词
成像系统
热像差
主动补偿
光刻机
投影物镜
imaging systems
thermal aberration
active compensations lighography
projection lens
