提出了一种原位的光刻机投影物镜偏振像差检测方法。定义一种新的偏振像差表征方法,推导了3对正交偏振态照明下空间像之差与偏振像差3个泡利项之间的互相关关系,并据此对交替相移掩模的3组差分空间像进行主成分分析进而求解偏振像差的各项泡利泽尼克系数。从理论上揭示了各偏振像差项在成像中的耦合规律,从而在测量原理上解决各项耦合问题,可同时测量偏振像差所有泡利项的前37阶泽尼克系数。在典型的深紫外光刻仿真条件下对所提方法进行随机偏振像差测试,其中3组泡利项的实部和虚部共6×37阶泡利泽尼克系数误差的标准差均在10 ^-3量级。测试结果验证了本方法的正确性和可行性。

An in-situ measurement method of polarization aberration (PA) in lithographic projection lens is proposed. A new characterization of PA is proposed, and a cross-correlation relationship among three Pauli terms of PA and the difference in aerial images under three pairs of orthogonal illuminated polarization states is derived. Based on this, the principal component analysis is performed on three groups of differential aerial images of alt-phase-shift mask to solve all the Pauli Zernike coefficients of PA. This paper describes the coupling of different Pauli terms theoretically in the imaging process and resolves the coupling problem through the principle of measurement based on this theory. As a result, first 37 orders of Zernike coefficients for all Pauli terms can be measured by the proposed method. In the condition of typical deep ultraviolet lithography, random PA tests of the proposed method are performed and the standard errors of 6×37 measured Pauli-Zernike coefficients (real and imaginary parts of three Pauli terms) are all in the order of 10 -3. Simulation results validate the correctness and the effectiveness of the proposed method.