摘要
提出一种基于阶梯相位环空间像主成分分析的光刻投影物镜波像差检测方法。通过对相位环空间像进行主成分分析和多元线性回归分析，构建了空间像光强分布与波像差之间的线性模型，并基于该模型实现了波像差检测。与使用孤立空检测标记的传统方法相比，使用新检测标记能够消除不同种类波像差之间的串扰问题，提高像差检测精度。同时，分析了空间像的离焦误差对波像差检测精度的影响，并提出了一种迭代算法用于确定实测空间像的离焦误差，其测量精度优于1nm。光刻仿真软件Dr．LiTHO的仿真结果表明，该法有能力检测12项泽尼克系数（Z5～Z15），最大系统误差约为1×10^-3λ，检测速度可提高一倍以上。
An in situ aberration measurement method based on a two-dimensional （2D） phase-shift rings target is proposed for quality evaluation of the lithographic projection lenses. A linear model between aerial-image intensity distribution and wavefront aberrations is built by principal component analysis （PCA） and multivariate linear regression analyses. Compared with the binary target in the AMAI-PCA method, the aerial images of the phase-shift rings contain more information which owns the ability of eliminating crosstalk between different kinds of aberrations, therefore, the accuracies of aberration measurement are improved. Impacts of aerial-image defocus error on the extractions of aberrations are analyzed. A measurement method for defocus error is also proposed. Simulations with the lithographic simulator Dr. LiTHO show that the proposed method can detect 12 terms of Zernike coefficients （Z3--Z16） with maximum error of 1 × 10-3λ. Simultaneously, the speed of aberration measurement is doubled because less aerial images need to be captured for the merit of applying the new 2D target.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2014年第2期100-107,共8页
Acta Optica Sinica
基金
国家自然科学基金重点项目（60938003,61205102.61275207）
关键词
成像系统
光刻
波像差检测
相位环
主成分分析
空间像
imaging systems
microlithography
aberration measurement
phase-shift rings
principal component analysis
aerial image
