基于近远场结合的微结构调制像差仿真  

Simulation of sample induced aberration for microstructure based on near-far fields

作　　者：鲍帅 高志山[1] 霍霄 刘秋言 乔文佑 杨文卓 袁群[1] 郭珍艳 BAO Shuai;GAO Zhishan*;HUO Xiao;LIU Qiuyan;QIAO Wenyou;YANG Wenzhuo;YUAN Qun;GUO Zhenyan(School of Electronic and Optical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China)

机构地区：[1]南京理工大学电子工程与光电技术学院,江苏南京210094

出　　处：《光学精密工程》2025年第5期716-727,共12页Optics and Precision Engineering

基　　金：国家自然科学基金资助项目(No.62327814,No.62175107,No.62205148);国家重点研发计划资助项目(No.2022YFF0706302,No.2023YFF0720601);江苏省高校青蓝工程。

摘　　要：基于光学成像原理的低相干显微干涉能够有效重建微结构表面的三维形貌,然而在测量高深宽比结构底部形貌的过程中探测光会受到结构调制产生波前畸变,导致测量失败。通过仿真计算能够得到微结构的像差调制规律,为其像差校正和补偿提供先验值。基于矢量衍射的电磁仿真方法能够准确地描述高深宽比微结构带来的复杂非线性调制,但此类方法数据量大、计算效率低,难以建立有效的三维仿真模型。针对该问题,提出一种近远场结合的像差仿真方法,以提高仿真的计算效率。采用基于全波模拟的时域有限差分法计算三维仿真中高深宽比微结构对探测光场的调制过程,得到经微结构调制后的探测光的近场分布,再通过带限缩放角谱法将探测光的近场分布传递至远场,实现调制像差的计算。通过实验装置测量了不同样品的调制像差验证了本文方法的准确性,同时仿真结果表明,在同等仿真精度下本文所提方法使计算速度提高了1倍以上。Coherence scanning interferometry(CSI)is widely employed for the measurement of microstructure morphology due to its non-contact nature,low detection cost,high efficiency,and robust stability.However,when measuring the bottoms of high aspect ratio microstructures using CSI,challenges arise,such as the inability of the detection light to focus and diminished detection capabilities resulting from the sample's structure.This phenomenon is attributed to aberrations induced by the modulation of light by the sample.By conducting simulations,the aberration modulation characteristics of microstructures was elucidated,thereby providing initial values for aberration correction and compensation,which en⁃hanced the measurement capabilities of CSI.The numerical calculation methods grounded in vector diffraction efficiently characterized complex modulation phenomena,including occlusion,diffraction,multiple reflections,and scattering of detection light,which were instigated by high aspect ratio microstructures.Notably,these methods require substantial data,exhibit low computational efficiency,and pose challenges in establishing three-dimensional models.To mitigate these issues,a sample-induced aberration simulation approach that leverages both near-field and far-field methodologies was proposed in this paper.This approach employed the Finite Difference Time Domain(FDTD)technique for full-wave simulation to compute the modulation process of high aspect ratio microstructures on the detection light field within a threedimensional framework.The near-field distribution of the detection light modulated by the microstructure was obtained,followed by transmission to the far field using the band-limited scaling angle spectrum method to assess the modulation aberration.Verification of the proposed method's accuracy was achieved through experimental measurements of modulation aberration across various samples.Simulation results further demonstrate that,under identical simulation conditions,the proposed method can enhance computational s

关 键 词：低相干显微干涉 样品调制像差 时域有限差分 带限缩放角谱 高深宽比微结构 

分 类 号：O436.1[机械工程—光学工程] TH741[理学—光学]