摘要
退偏器在深紫外光刻机照明系统中具有重要作用。尽管相关的设计、制造、性能评估已有一些报道,但是,相应的检测手段大多工作在可见光波段,目前仍缺乏直接对深紫外特定波长应用的退偏器进行性能检测的方法。本文提出了一种与激光光强波动无关的248 nm退偏器检测方法,使用248.372 nm波长的KrF准分子激光器作为光源,利用预起偏和偏振分光设计克服了激光光强波动造成的不利影响。误差分析表明,该方法适用于退偏器性能检测,绝对系统误差小于0.1226%,随机误差约0.2000%。验证实验和稳定性实验表明,测量偏振度均值与理论值高度一致,重复性水平与分析预期相当,再现性水平仅略差于重复性水平。这一方法为248 nm光刻机照明系统中使用的退偏器提供了一种稳定有效的离线性能检测手段。
Objective With the development of the semiconductor industry,the requirement for photolithography resolution is significantly increasing.As the resolution increases,the polarized illumination is required to improve the image contrast.Depolarizers are devices that convert incident-polarized light into unpolarized light,with the degree of polarization(DOP)of the output light as a core performance index.Depolarizer plays an essential role in the deep ultraviolet(DUV)lithography tool illumination system.Despite some reports on design,manufacture,and performance evaluation,most traditional detection methods work in the visible band.There is still no direct method for detecting the performance of the depolarizer for specific DUV wavelength applications.The key problem is that the high-level control requirement of the measurement error contradicts the insufficient performance of the light source and polarizing devices.To solve this problem,this study proposes a method for detecting 248 nm depolarizer independent of laser intensity fluctuation(Fig.2 Schematic of the method,Fig.7 Experimental equipment).The 248.372 nm excimer krypton fluoride(KrF)laser is used as the light source.The adverse effects caused by the laser intensity fluctuation are overcome through pre-polarizing and polarization beam splitting design.The measurement error is analyzed and verified experimentally.The DOP measurement value is highly consistent with the theoretical value,verifying the validity of the proposed method.The DOP results in the repeatability and reproducibility tests show very low standard deviations and variation coefficients,which are consistent with the analysis level.The proposed method provides a stable and effective tool for offline performance detection of the depolarizer used in the 248 nm lithography tool illumination system.Methods To detect the depolarizer used in 248 nm lithography,the light source needs to be monochromatic and high powered to eliminate dispersion and be effective under the conditions of a large beam area
作者
张灵浩
夏克贵
马兴华
朱玲琳
曾爱军
黄惠杰
Sergey Avakaw
Zhang Linghao;Xia Kegui;Ma Xinghua;Zhu Linglin;Zeng Aijun;Huang Huijie;Sergey Avakaw(Laboratory of Information Optics and Optoelectronic Technology,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China;Company of KBTEM-OMO Republication Unitary Scientific and Production Enterprise,Minsk 220033,Belarus)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2022年第4期20-28,共9页
Chinese Journal of Lasers
基金
上海市自然科学基金面上项目(19ZR1464300)
上海市集成电路科技支撑专项(20501110600)
上海市政府间科技合作计划(20500711300)。
关键词
测量
偏振检测
退偏器
深紫外
光刻
误差分析
measurement
polarization detection
depolarizer
deep ultraviolet
optical lithography
error analysis
