极紫外光刻光源驱动激光光斑高精度检测技术研究  

High-Precision Spot Detection of Driving Laser for Extreme Ultraviolet Lithography Light Sources

作　　者：李鑫鹏 于德洋[1] 郭劲[1] 陈飞[1] 潘其坤[1] Li Xinpeng;Yu Deyang;Guo Jin;Chen Fei;Pan Qikun(State Key Laboratory of Laser Interaction with Matter,Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,Jilin,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院长春光学精密机械与物理研究所激光与物质相互作用国家重点实验室,吉林长春130033 [2]中国科学院大学,北京100049

出　　处：《中国激光》2023年第2期64-71,共8页Chinese Journal of Lasers

基　　金：国家重点研发计划(2018YFE0203200);国家自然科学基金(62104223)。

摘　　要：为了实现极紫外光刻光源驱动激光光斑位置的高精度、宽范围、快响应检测,设计了一种高重复频率窄脉冲信号多通道同步采集处理电路,并提出了基于高斯光斑模型的二级扩展误差补偿算法,可以为极紫外光刻光源驱动激光指向控制提供高精度反馈调节量。首先,介绍了光斑位置检测系统的结构组成与四象限探测器的基本检测原理;然后在考虑探测器半径、光斑半径以及沟道宽度等因素影响的前提下对误差补偿函数进行改进,并对改进的二阶扩展误差补偿算法进行了仿真分析;接着介绍了用于高重复频率窄脉宽信号的多通道同步高速采集电路;最后搭建了实验平台,对改进的算法进行验证。实验结果显示,二阶扩展误差补偿算法的均方根误差为0.0042,最大绝对误差为0.0092 mm,绝对误差的平均值为0.0034 mm;与二阶误差补偿算法相比,二阶扩展误差补偿算法的均方根误差、最大绝对误差和绝对误差的平均值分别降低了83.06%、85.28%和83.50%。表明二阶扩展误差补偿算法与二阶误差补偿算法相比,具有明显的优越性及实用性,在扩展了光斑位置检测范围的同时,光斑位置的检测精度也得到了明显的提升,解决了传统算法无法兼顾计算速度与检测精度的问题。Objective Currently,the laser induced plasma(LPP)technology is the best method to obtain high quality extreme ultraviolet(EUV)light source,whereby a high-power,high-frequency,short-pulse CO_2 laser under the main oscillation power amplification technology is used to bombard a droplet tin target to obtain high-quality extreme ultraviolet signals.In an EUV lithography light source system,the laser beam direction is significantly affected by the cascade when the laser beam passes through the four-stage amplification system.During the amplification process,the optical components in the optical path between the amplifiers feature different thermal distortions under different laser powers;all the four-stage amplifiers used are high-power laser amplifiers,and the vibrations caused by the cooling device during operation are unavoidable.These factors cause the center of the laser beam to deviate from the optical axis and affect the EUV conversion efficiency.Therefore,for EUV lithography light source systems,the further research on beam pointing stability is necessary to achieve a certain EUV conversion efficiency.At present,four-quadrant detectors are widely used in high-precision laser measurements owing to their fast response,high position resolution,high measurement accuracy,and simple data processing.However,a high-precision spot location algorithm based on a four-quadrant detector is generally complex.Thus,during high-repetition-frequency pulse signal detection,the real-time requirements of spot location calculations cannot be met.Therefore,it is necessary to develop a new algorithm that considers the accuracy of spot location detection and its real-time performance.Methods In this study,we first obtain the four-quadrant detector output signal under the Gaussian distribution model for spot energy distribution and subsequently calculate the initial solution for the spot position under the influence of the detector radius and dead zone using the normalization and difference algorithm.The initial spot position solution

关 键 词：测量 光斑位置检测 极紫外光刻光源 高重复频率窄脉冲 CO_(2)激光 四象限探测器 

分 类 号：TN215[电子电信—物理电子学]