【作者】 李小强；

【导师】 赵永蓬；

【作者基本信息】 哈尔滨工业大学 ， 物理电子学， 2014， 硕士

【摘要】 极紫外(EUV)光刻技术被认为是最有前途的下一代光刻技术候选人，极紫外光刻光源是极紫外光刻技术的核心。在目前主流的产生极紫外辐射光的技术中，激光辅助放电等离子体(LDP)技术因工作介质Sn具有高能量转换效率和收集效率等优点，使其更加适合工业化大规模生产，从而受到了极紫外光刻界的青睐。与毛细管放电技术的工作介质Xe不同，Sn作为固态，必须先用激光烧蚀将其气化产生初始等离子体，再用主脉冲对等离子体放电来产生13.5nm极紫外辐射，因此必须设计一套适用于Sn介质的LDP机制极紫外光刻光源。本论文在毛细管放电极紫外光刻光源的基础上设计改造得到LDP极紫外光刻光源装置，并在此装置上实现了Sn等离子体13.5nm(2%带宽)EUV辐射输出，获得了EUV辐射输出的最佳实验条件。这一实验结果达到了世界先进水平，填补了我国在LDP机制EUV光刻光源方面的空白，为后续展开的EUV光源研究奠定了实验基础。理论方面分析了Sn等离子体13.5nm(2%带宽)EUV辐射的来源，用Cowan程序计算了Sn8+~Sn12+离子的能级参数，得到Sn8+~Sn12+离子能级跃迁在13.5nm附近的谱线分布；描述了Sn初始等离子体的Z箍缩过程，分析了Sn高价离子产生过程；介绍了等离子体诊断法的相关理论，以及用Boltzmann法计算电子温度、Stark展宽法计算电子密度的原理。实验方面选取了三条Sn原子谱线来计算等离子体的物理状态，研究了激光能量改变时Sn等离子体物理状态的变化规律，得出在大气或真空环境下等离子体的电子温度和电子密度随激光能量的变化较小，电子温度Te在0.6-0.8eV之间，电子密度Ne在(2.0-2.7)×1017cm-3之间；设计了激光器与光谱仪CCD的延时系统，研究了不同延时条件下等离子体物理状态的变化规律，得出大气或真空环境下等离子体的物理状态在不同延时条件下的变化较小，电子温度Te在0.7-0.9eV之间，电子密度Ne在(2.0-2.5)×1017cm-3之间。构建了LDP极紫外光刻光源的实验装置，在该装置上获得了Sn等离子体13.5nm极紫外辐射输出；介绍了激光脉冲与主脉冲电流延时的实现过程，研究了激光与主脉冲电流延时对Sn等离子体EUV辐射输出的影响，得出EUV辐射输出的最佳延时时间为2.5μs；研究了激光能量对EUV辐射的影响，得出能量小于20mJ时光谱强度与激光能量成正比，大于20mJ时光谱强度与激光能量无关。更多还原

【Abstract】 Extreme Ultraviolet (EUV) lithography is considered to be the most promisingcandidate of next generation lithography. EUV light source is the most importanttechnology of EUV lithography. Of all the technology to produce EUV radiation,laser-assisted discharge plasma (LDP) has got the favor of scientists and is regarded asthe most suitable technology for lithography industry because of high conversionefficiency and collection efficiency of its material-Sn. Unlike the Xe material ofcapillary discharge plasma technology, Sn is solid and must be gasified beforedischarging. So a LDP EUV lithography source is needed. We have designed a newLDP extreme ultraviolet light source device based on an old capillary discharge plasmaEUV light source, and the Sn plasma13.5nm (2%bandwidth)EUV output is gained.The influence of laser energy and delay between laser and main pulse to the EUVradiation output is analyzed, and the best condition of EUV source output is got. This isthe first time for China to get the EUV radiation of Sn, which measures up to advancedworld standard.Theoretically, the source of Sn13.5nm (2%bandwidth) EUV radiation is analyzed,and the Sn8+~Sn12+ion level parameters is calculated using Cowan program to get thespectral distribution of ion energy level transition near13.5nm. Z-pinch theory of Snplasma is described and process of the high ions of Sn is analyzed. We have talkedabout the physical progress in plasma, the radiation related to plasma and broadeningtypes according to the plasma diagnostics. The Boltzmann method is introduced tocalculate the electron temperature, Stark broadening method to calculate the principle ofelectron density.Experimentally, research of electron temperature and density of Sn plasma isintroduced. We have selected three atomic spectrums to calculate the physical state ofSn plasma. It is concluded that electron temperature and density range is small inatmosphere and vacuum environment, along with the change of laser energy and delaytime between the laser and CCD. The average electron temperature of Sn plasma isabout0.6-0.8eV and electron density is about (2.0-2.7)×1017cm-3in the study of energy,and0.7-0.9eV and electron density is about (2.0-2.5)×1017cm-3in the study of delaytime.Equipment of LDP EUV light source and the working process to obtain13.5nmEUV output is introduced. The delay time between laser and the main pulse is analyzedin detail. The influence of delay time between laser and the main pulse is studied to theoutput of EUV source and the best delay time is obtained of about2.5μs. Finally the paper studies the influence of laser energy to the EUV output. It is concluded that theoutput of EUV source is proportional to the laser energy when the energy is less than20mJ, and spectral intensity has nothing to do with the laser energy when the energy isgreater than that.更多还原