High-order wavefront aberration measurement method for hyper-NA lithographic projection lens based on a binary target and rotated regression matrix

Abstract

Abstract A high-order wavefront aberration (HWA) measurement method for a hyper-NA lithographic projection lens based on a binary target with eight directions and rotated regression matrix is proposed. A linear model between the aerial image intensity distribution of the hyper-NA lithographic projection lens and HWAs is built by principal component analysis and regression matrix rotation. Compared to the conventional method using a binary target with six directions, the proposed method improves the efficiency of pupil sampling, increases the modeling speed, extends the measuring range of the wavefront aberrations, and detects the HWAs of the hyper-NA lithographic projection lens accurately. The lithographic simulator PROLITH is used to validate the accuracies of the HWA measurement and analyze the impact of the illumination types of source on the accuracy of the HWA measurement, as well as the polarization rotation of illumination, the sample interval of the aerial images, and the manufacturing error of the test target. The results show that the proposed method retrieves 60 terms of Zernike coefficients ( Z 5 – Z 64 ) with measurement accuracy greater than 1.03 × 10−3 λ .