摘要
极紫外光源在半导体制造中的掩模检测、显微成像以及光谱计量等环节中有着重要的应用。激光诱导放电等离子体是产生极紫外光源的重要技术手段之一,搭建了一套二氧化碳激光诱导放电产生锡等离子体的实验装置,对产生的极紫外光谱进行了收集探测,并结合辐射磁流体动力学模拟对极紫外的辐射特性进行了分析。实验对比了激光等离子体和放电等离子体的极紫外辐射特性的区别,发现放电电压对激光诱导放电等离子体极紫外光的带内辐射强度有着重要影响。模拟发现,当电压为15 kV时,极紫外辐射总能量达到65.0 mJ,转化效率达到0.23%,光谱纯度达到1.69%。
Objective With the continuous decrease in feature size in the semiconductor industry,extreme ultraviolet lithography(EUVL)is becoming increasingly crucial in ultrahigh integrated circuit manufacturing.The emission characteristics of tin(Sn)in terms of its high conversion efficiency(CE)and spectral purity(SP)make it the best choice for current EUVL systems.Laser-produced plasma(LPP)and laser-induced discharge plasma(LDP)are the most important technical methods for generating extreme ultraviolet rays.LDP has the low cost,simple structure,high operation rate,and high energy injection,and it is promising for mask inspection,microscopic imaging,and spectral metrology.Unlike the LPP source,many parameters,such as the electrode structure,discharge gap,laser wavelength,and current rise rate,make it difficult to design an LDP source;therefore,it is necessary to investigate the influence of these parameters on the performance of the LDP EUV source.Methods An experimental setup is designed to investigate the laser-induced discharge of tin plasma.A pulsed carbon dioxide laser is used to ablate a tin plate cathode and produce an expanding pre-ionized plasma as the discharge medium,decreasing the threshold for the breakdown voltage.A vacuum arc gradually formes between the cathode and the stainless-steel hemisphere anode,and the current bombards the electrodes and generates more plasma.The time-domain waveform of the current is recorded,and the extreme ultraviolet spectra of the LPP and LDP are analyzed.A radiative magneto-hydrodynamic program Z*is used to simulate the laser plasma and discharge plasma.Results and Discussions The experimental LPP-EUV spectrum shows a peak at 13.7 nm when the laser energy is 145 mJ,whereas the peaks of the LDP spectra show a significant red shift compared to those of the LPP spectrum(Fig.3).When the voltage is 7 kV,the in-band(bandwidth of 2%at 13.5 nm wavelength)spectral intensity of the LDP does not significantly increase compared with that under the LPP condition.At a voltage of 15 kV,the in
作者
王均武
玄洪文
王新兵
Vassily S.Zakharov
Wang Junwu;Xuan Hongwen;Wang Xinbing;Vassily S.Zakharov(GBA Branch of Aerospace Information Research Institute,Chinese Academy of Sciences,Guangzhou 510530,Guangdong,China;Wuhan National Laboratory for Optoelectronics,Wuhan 430074,Hubei,China;University of Chinese Academy of Sciences,Beijing 100049,China;Kurchatov Institute,National Research Center,Moscow 125047,Russia)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2024年第7期172-179,共8页
Chinese Journal of Lasers
基金
广州市基础与应用基础研究专题(2023A04J0024)
中科院人才引进计划(E33310030D)
中国科学院空天信息创新研究院自主部署项目(E2Z2D101,E1Z1D101)。
关键词
激光光学
激光诱导放电等离子体
极紫外光
辐射磁流体动力学
转化效率
laser optics
laser-induced discharge plasma
extreme ultraviolet
radiative magneto-hydrodynamics
conversion efficiency
