Open AccessDesign of an illumination system for high numerical aperture anamorphic extreme ultraviolet projection lithography
Author(s) -
Quan Hao,
Yuelei Xu,
Ke Liu,
Yanqiu Li,
Lihui Liu,
Meng Zheng
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.419064
Subject(s) - optics , conic section , aperture (computer memory) , entrance pupil , lithography , tilt (camera) , reticle , numerical aperture , facet (psychology) , exit pupil , projection (relational algebra) , physics , computer science , optoelectronics , pupil , geometry , mathematics , wavelength , psychology , social psychology , personality , algorithm , acoustics , wafer , big five personality traits
The illumination system design for high numerical aperture (NA) anamorphic objectives is a key challenge for extreme ultraviolet lithography. In this paper, a reverse design method of the off-axis mixed-conic-surface-type relay system and an automatic arrangement method of field facets are proposed to design a high NA anamorphic illumination system. The two off-axis relay mirrors are fitted into different conic surfaces based on the conjugation of the mask plane and field facet and that of the illumination exit pupil and pupil facet. To eliminate ray obscuration between neighboring field facets, the field facets are automatically arranged according to the distances that are determined by the relative tilt angles of neighboring field facets under the current illumination mode. The proposed methods are applied in the design of an illumination system matching the NA0.60 anamorphic objective. Simulation results show that the uniformity of the scanning energy distribution can reach 99% on the mask plane under different illumination modes.