光学学报, 2014, 34 (9): 0905002, 网络出版: 2014-08-15
极紫外光刻含缺陷多层膜衍射谱仿真简化模型
Simplified Model for Defective Multilayer Diffraction Spectrum Simulation in Extreme Ultraviolet Lithography
衍射 极紫外光刻 多层膜模型 单平面近似 diffraction extreme ultraviolet lithography multilayer model single surface approximation
摘要
建立了一个极紫外光刻含缺陷多层膜衍射谱仿真简化模型,采用相位突变和反射系数振幅衰减表示缺陷对多层膜反射光的影响,得到了含缺陷多层膜衍射谱的解析表达式。简化模型中,相位突变量由多层膜表面以下第6层膜的缺陷形态决定,反射系数振幅衰减量由基底的缺陷形态决定。与改进单平面近似(SSA)模型相比,仿真速度基本一致的情况下,简化模型提高了含缺陷多层膜衍射谱仿真的精度,6°入射时,衍射谱的0~+3级衍射光振幅的仿真误差减小50%以上,并且不同入射角情况下,尤其在入射角小于12°时,振幅误差稳定。得到了含缺陷多层膜衍射谱的解析表达式,可进一步理论分析缺陷对多层膜衍射谱的影响,为得到掩模缺陷的补偿公式奠定了基础。
Abstract
A simplified model is developed for defective multilayer spectrum simulation in extreme ultraviolet (EUV) lithography. Influence of defect on the reflected light is modeled by phase perturbation and amplitude attenuation of reflection coefficient. An analytical expression of defective multilayer diffraction spectrum is given. In the simplified model, the phase perturbation is dependent on the defect parameters of the 6th layer of the multilayer and the amplitude attenuation is dependent on the bottom defect parameters. Compared to advanced single surface approximation (SSA) model, accuracy of the multilayer spectrum of the simplified model is improved with nearly the same simulation time. The amplitude errors of 0~+3 orders of the multilayer spectrum are decreased more than 50% in 6° incidence angle. The errors are also with little fluctuation in different incidence angles, especially smaller than 12°. The analytical expression of defective multilayer diffraction spectrum is beneficial to analysis the effects of defect to multilayer spectrum and provides the basis for formulation of defective mask correction.
刘晓雷, 李思坤, 王向朝. 极紫外光刻含缺陷多层膜衍射谱仿真简化模型[J]. 光学学报, 2014, 34(9): 0905002. Liu Xiaolei, Li Sikun, Wang Xiangzhao. Simplified Model for Defective Multilayer Diffraction Spectrum Simulation in Extreme Ultraviolet Lithography[J]. Acta Optica Sinica, 2014, 34(9): 0905002.