基于归一化的高精度EUV反射率测试技术研究  

High-Precision Extreme Ultraviolet Reflectometry Based on Normalization

作　　者：张良乐 韩晓泉 谢婉露 吴晓斌 方旭晨 高梓翔 沙鹏飞 王魁波 Zhang Liangle;Han Xiaoquan;Xie Wanlu;Wu Xiaobin;Fang Xuchen;Gao Zixiang;Sha Pengfei;Wang Kuibo(R&D Center of Optoelectronic Technology,Institute of Microelectronics of the Chinese Academy of Sciences,Beijing 100029,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院微电子研究所光电技术研发中心,北京100029 [2]中国科学院大学,北京100049

出　　处：《中国激光》2024年第7期196-202,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金面上项目(62071464)。

摘　　要：基于使用气体放电等离子体(DPP)极紫外(EUV)光源自研的小型反射率测试装置,分析了DPP光源参数及不同型号探测器对反射率测试的影响,提出了一种能量归一化的反射率测试方法,并测试了13.5 nm波长下Mo/Si多层膜反射镜的反射率特性。研究结果表明:在相同光源参数下,SXUV100型探测器的极紫外能量探测性能优于AXUV100G型;通过归一化使光能量波动对反射率测试光束的波动误差从6.2%降低到0.64%,多层膜反射镜的峰值反射率的测量重复性从4.34%提高到0.69%,与国外同等实验装置精度相当,实现了高精度反射率测试,可为极紫外光刻机的光学元件提供反射率测试。Objective The precision of reflectivity measurements of the extreme ultraviolet(EUV)lithography machine must be greater than 0.06%;therefore,the high-precision measurement of the reflectivity of EUV optical components is particularly important.The influence of various factors in the measurement device,such as the energy stability of the light source,performance of the energy detector,and signal-to-noise ratio(SNR)of the data acquisition module must be minimized to achieve high-precision EUV reflectance measurement.Most high-precision measurements of the reflectivity of the EUV-band optical components conducted worldwide are based on synchronous radiation light sources.However,the cost of synchronous radiation light sources is high and the quantity is small with limited machine time,which cannot meet the production measurement and laboratory application requirements for EUV optical components.Therefore,the development of a reflectometer with a compact size and convenient measurements is necessary.Compared with synchronous radiation light sources,small light sources have poor single-pulse energy stability,and significant fluctuations and attenuation of energy during long-term operation greatly affect the repeatability of reflectivity measurements.Therefore,to eliminate the impact of the energy fluctuations inherent in the light source,normalization is essential during highprecision reflectivity measurements.In this study,a reflectivity testing device based on a discharge plasma(DPP)light source is developed.We analyze the effects of the EUV light source parameters,detector types,and other factors on the reflectometer and propose an effective energy-normalization method.The testing of the reflectivity of the multi-layer mirrors indicate that the impact of light source fluctuations reduces significantly,providing a reference for other EUV-related energy tests.Methods To improve the repeatability of reflectivity testing,the energy of the light source must be normalized.We adopted a simple method of energy normalizatio

关 键 词：极紫外 气体放电等离子体光源 反射率 能量探测 归一化 

分 类 号：O434[机械工程—光学工程] TN23[理学—光学]