摘要
针对复杂结构对准标记仿真需求,联合严格耦合波法和分层近似法提出一种对准标记鲁棒性分析方法。利用该方法构建仿真模型:以晶圆质量和信噪比为评价函数,研究了标记槽深、槽宽、膜层厚度和侧壁对称变形等参数变化对标记鲁棒性的影响;以对准误差为评价函数,研究了侧壁非对称变形对标记鲁棒性的影响。并结合对准标记鲁棒性分析结果明晰了光刻机提升标记工艺适应性的策略。最后借助VirtualLab商业软件和实验平台,验证了分析方法的有效性和准确性。所提方法和给出的工艺适应性策略,对于对准标记设计优化和光刻机对准精度提升具有重要的理论意义和应用价值。
Objective With the continuously shrinking lithography process nodes,new materials,and technologies are constantly introduced,which exerts different effects on the mark in the lithography machine alignment system.Therefore,improving the robustness of alignment marks is crucial for highprecision alignment.It takes extensive time and cost to verify the robustness of alignment marks based on experimental methods.The industry tends to adopt simulation experiments to improve research efficiency and economy.The theory of alignment mark simulation can be divided into scalar diffraction theory and vector diffraction theory.For alignment marks with small periods or complex structures,the rigorous coupled wave method in vector diffraction theory has good computational accuracy and speed.For the alignment mark simulation with complex structures,a robustness analysis method of alignment marks is proposed by combining the rigorous coupled wave method and the layered approximation method.The robustness of marks is analyzed by this method,and the lithography strategy of improving the process adaptability of the mark is clarified with the analysis results.The proposed method and the given process adaptability strategy show theoretical significance and application value for the alignment mark design and alignment accuracy of scanners.Methods For the ideal mark with the standard surface,a vector diffraction simulation model can be built by the rigorous coupled wave method.For alignment marks with sidewall deformation due to process influence,it is difficult to directly establish the surface function,as the surface is nonstandard anymore.Therefore,a robust analysis method of alignment marks is proposed by combining the rigorous coupled wave method and the layered approximation method to meet the requirements.The alignment mark with sidewall deformation is divided into multiple layers with equal thickness.When the number of layers is large enough,each layer can be approximated as a rectangular structure.The alignment mark with comple
作者
周光迎
齐月静
李亮
姜淼
师江柳
么铭怡
Zhou Guangying;Qi Yuejing;Li Liang;Jiang Miao;Shi Jiangliu;Yao Mingyi(Institute of Microelectronics of the Chinese Academy of Sciences,Beijing 100029,China;Beijing Superstring Academy of Memory Technology,Beijing 100176,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《光学学报》
EI
CAS
CSCD
北大核心
2023年第11期109-118,共10页
Acta Optica Sinica
关键词
光刻
对准标记
严格耦合波法
分层近似法
鲁棒性
工艺适应性
lithography
alignment mark
rigorous coupled wave method
layered approximation method
robustness
process adaptability
