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Proceedings Paper

Experimental determination of aberration in lithographic lens by aerial image
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Paper Abstract

In this paper, we propose a method named as AMAI-PCA to extract aberration levels using aerial image measurements and present its experimental results on lithographic tools. Based on physical simulation and statistical analysis, a linear regression matrix is obtained establishing a connection between principal component coefficients of specific aerial images and Zernike coefficients. In the application phase, the aberrations of the projection lens are solved via the use of this regression matrix. An engineering model is established based on an extension of theoretical model that incorporates all the significant systematic errors. The performance of the engineering model applied on a 0.75 NA ArF scanner is reported. In the experiment, measurement marks oriented in orthogonal directions are used and aerial images on 9 field points are measured. To verify the repeatability of this technique, every point is measured 20 times. By inputting the aerial images into the engineering model, Zernike coefficients are solved and the results are analyzed. The wafer exposures were performed to evaluate the results of aberration correction.

Paper Details

Date Published: 30 September 2011
PDF: 10 pages
Proc. SPIE 8169, Optical Fabrication, Testing, and Metrology IV, 816909 (30 September 2011); doi: 10.1117/12.896319
Show Author Affiliations
Lifeng Duan, Shanghai Institute of Optics and Fine Mechanics (China)
Graduate School of the Chinese Academy of Sciences (China)
Shanghai Micro Electronics Equipment Co., Ltd. (China)
Xiangzhao Wang, Shanghai Institute of Optics and Fine Mechanics (China)
Guanyong Yan, Shanghai Institute of Optics and Fine Mechanics (China)
Anatoly Bourov, Shanghai Micro Electronics Equipment Co., Ltd. (China)


Published in SPIE Proceedings Vol. 8169:
Optical Fabrication, Testing, and Metrology IV
Angela Duparré; Roland Geyl, Editor(s)

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