【作者】 殷可为；

【导师】 邢廷文； 林妩媚；

【作者基本信息】 中国科学院研究生院（光电技术研究所） ， 光学工程， 2014， 博士

【摘要】 光刻机是制作极大规模集成电路的核心设备。光刻照明系统是光刻机的重要组成部分，它包括扩束系统、光束整形系统、匀光系统和照明物镜系统，其主要作用是利用衍射元件实现离轴照明以及利用复眼透镜提高照明均匀性。本文围绕ArF光刻照明系统中的微光学器件（衍射元件与复眼透镜）产生的杂散光展开研究。因杂散光的存在会严重影响光刻机最终的曝光质量，所以本课题研究是保证光刻机曝光质量的关键技术之一。研究的最终目的在于能够采取有效措施抑制微光学元件产生的杂散光。论文的主要研究工作包括以下几个部分：(1)衍射元件设计算法的研究。通过对以往衍射元件设计算法的调研与比较，提出了一种混合型算法用以设计衍射元件。该算法集多种算法优点，从设计源头上减小衍射元件产生的杂散光。(2)衍射光学元件设计参数对杂散光的影响。采用标量衍射理论，详细分析了衍射元件产生高级次衍射杂散光的原因，并在此基础上提出了一个新的评价参数Trp。它与光波波长成正比，与衍射光学元件的采样单元尺寸以及远场衍射角成反比。通过对该参数的调节能够有效抑制高级次衍射杂散光的产生。(3)衍射光学元件加工误差对杂散光的影响。详细介绍了衍射元件的制作工艺，并对加工误差的来源进行了分析。接着分析了各加工误差对杂散光的影响，其中包括对台阶量化误差、对准误差、随机刻蚀深度误差以及球形刻蚀深度误差的分析。为了达到设计要求，对加工提出了改进意见。(4)搭建实验平台，对实现四级照明的衍射元件进行了测试，其中包括对衍射元件表面轮廓的检测以及对光束整形效果的测试。并将实验结果与仿真结果进行了对比，对衍射元件产生的主要杂散光进行了分析，讨论了抑制衍射杂散光，提高衍射效率的方法。(5)详细研究了复眼透镜的匀光原理，在ASAP软件中通过光线追迹的方法，数值仿真了复眼透镜和聚光镜组实现匀光的过程。分析了双排复眼透镜中主要的加工误差导致的杂散光对匀光效果的影响，并对加工提出了改进意见。(6)介绍了光刻系统的总体结构；计算了整个系统的能量利用率，并分析了衍射元件产生的杂散光在像面上所占比例；采用Prolith软件分析了衍射元件产生的杂散光对光刻曝光质量的影响。对深紫外光刻照明系统中微光学元件产生的杂散光进行深入细致的研究有利于减小光刻系统中的杂散光，保证最终的曝光质量。论文的这些研究成果为深紫外光刻照明系统的研制提供了有价值的参考。更多还原

【Abstract】 Lithography is the core equipment for the production of ultra large scaleintegrated circuit. Illumination system, as one of the most important parts oflithography, includes beam expander system, beam shaping system, uniformillumination system and illumination lens system. It enables to realize off-axisillumination modes with diffractive optical element and supply high uniformityintensity distribution on the mask with fly’s eye condenser.In this paper, the stray light of micro optical elements (diffractive optical elementand fly’s eye condenser) in the ArF lithography illumination system is studied. Due tothe stray light will seriously affect the quality of the final exposure, this research isone of the key technologies to ensure the quality of exposure. The purpose of thispaper is that many effective measures can be adopted to suppress the stray light ofmicro optical elements. The main research work in this paper includes the followingparts:(1) Algorithms for the Design of Diffractive Optical Element for Beam Shaping.Through the investigation and comparison of many design algorithms of thediffractive optical elements, a hybrid algorithm is proposed to design diffractiveoptical elements. This advanced algorithm can reduce stray light of diffractive opticalelements effectively.(2) Influences of design parameters of diffractive optical element on stray light.Scalar diffraction theory is used to analysis the reasons of high order diffraction light.Then, a new parameter Trpis defined. It is proportional to the wavelength andinversely proportional to the far-field max diffraction angle and the size of diffractiveoptical element cells. Through the simulation analysis, the stray light of highdiffractive orders can be suppressed effectively by regulating this new parameter.(3) Influences of fabrication errors of diffractive optical element on stray light. Fabrication methods of diffractive optical elements are introduced and the influencesof fabrication errors are analyzed, including step quantization error, alignment error,random etching depth error, as well as spherical etching depth error. Finally,improvements are suggested.(4) An experiment is used to test the performance of diffractive optical elements,including some tests about the surface of diffractive optical elements and tests aboutbeam shaping. The experimental results are compared with the simulation results.Finally, some methods of suppression diffractive stray light are discussed.(5) The method of ray tracing in ASAP is used to simulate the uniform processwith fly’s eye condenser. Fabrication errors of fly’s eye and influences are analyzed.Finally, Fabrication improvements are suggested.(6) Based on the structure of lithography system, energy efficiency of thelithography system is caculatied and energy of stray light from diffractive opticalelement is analyzed. In addition, influences of stray light of diffractive opticalelements on the performance of lithography are discussed with Prolith software.These researches have advantages of reduction of stray light in lithographysystem and the results provide valuable references for the development of deepultraviolet lithography illumination system.更多还原