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Proceedings Paper

Novel method for measuring axial aberrations of projection optics for lithographic tools
Author(s): Mingying Ma; Fan Wang; Xiangzhao Wang
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Paper Abstract

As the critical dimension shrinks, degradation of lithographic quality because of axial aberrations in the projection optics has become more obvious. To minimize the adverse effect of axial aberrations on imaging, accurate in-situ measurement of axial aberrations is necessary. In this paper, a novel in-situ method to measure axial aberrations is proposed. In this novel method, a new type of measurement mark for measuring the axial aberrations is designed. By using new marks, the axial aberrations can be obtained by the linewidth variation of two bars in the marks. The linewidth variation is proportional to the focus shift in which the measurement mark is exposed. The proportional factor can be obtained by the simulation software Prolith. From the linewidth variation and proportional factor, the focus shift of the measurement mark in different positions can be calculated. The axial aberrations can be obtained by the calculated focus shift. In this novel measurement method, both the measurement procedure and data-processing are simple. As the measurement accuracy of the focus shift in z direction is increased, the measurement accuracy of axial image quality increases by more than 25%.

Paper Details

Date Published: 19 November 2007
PDF: 6 pages
Proc. SPIE 6724, 3rd International Symposium on Advanced Optical Manufacturing and Testing Technologies: Design, Manufacturing, and Testing of Micro- and Nano-Optical Devices and Systems, 67240N (19 November 2007); doi: 10.1117/12.782572
Show Author Affiliations
Mingying Ma, Shanghai Micro Electronics Equipment Co. Ltd. (China)
Fan Wang, Shanghai Micro Electronics Equipment Co. Ltd. (China)
Xiangzhao Wang, Shanghai Institute of Optics and Fine Mechanics (China)


Published in SPIE Proceedings Vol. 6724:
3rd International Symposium on Advanced Optical Manufacturing and Testing Technologies: Design, Manufacturing, and Testing of Micro- and Nano-Optical Devices and Systems
Sen Han; Tingwen Xing; Yanqiu Li; Zheng Cui, Editor(s)

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