@inproceedings{c3cbc4918b7a4a22b2b9247b1fb7594f,
title = "Wavefront Fitting of Different Obscuration Shapes in Anamorphic Extreme Ultraviolet Lithography Projection Objective",
abstract = "The anamorphic extreme ultraviolet lithography (EUVL) projection objective (NA=0.55) features an elliptical entrance pupil and a circular exit pupil with central obscuration. However, wavefront fitting using conventional Zernike polynomials is limited to circular/annular pupils. In this paper, orthonormal polynomials are constructed for different pupils. Three types of central obscurations are analyzed, and the selection of optimal obscuration shape is discussed in the context of balancing wavefront fitting accuracy and obscuration area. The simulation results prove the effectiveness of these polynomials in fitting accuracy and stability, bridging the gap between traditional wavefront fitting and the demand of anamorphic EUVL system.",
keywords = "Central Obscuration, EUVL Projection Objective, Wavefront Fitting, Zernike Polynomials",
author = "Zhenkun Zhang and Yanbei Nan and Yanqiu Li",
note = "Publisher Copyright: {\textcopyright} 2025 SPIE.; 9th International Workshop on Advanced Patterning Solutions, IWAPS 2025 ; Conference date: 14-10-2025 Through 15-10-2025",
year = "2025",
month = dec,
day = "3",
doi = "10.1117/12.3088541",
language = "English",
series = "Proceedings of SPIE - The International Society for Optical Engineering",
publisher = "SPIE",
editor = "Yayi Wei and Tianchun Ye",
booktitle = "Ninth International Workshop on Advanced Patterning Solutions, IWAPS 2025",
address = "United States",
}