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Proceedings Paper

Data refinement for robust solution to the inverse problem in optical scatterometry
Author(s): Jinlong Zhu; Hao Jiang; Chuanwei Zhang; Xiuguo Chen; Shiyuan Liu
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Paper Abstract

Optical scatterometry is widely used in the process control of integrated circuits (IC) manufacturing due to its inherent advantages such as nondestruction, high sampling rate, large aerial coverage and low-cost. However, in the conventional inverse problem solvent of optical scatterometry, the measurement errors are usually excessively simplified as normally distributed errors, which deviate from the actual complex ones. In this work, we will demonstrate that there exist typical outlying measurement errors in the measurement signature, and these outlying measurement errors will notably affect the result of each iteration step in the conventional Gauss-Newton (GN) method. By performing a method based on the principle of least trimmed squared estimator (LTS) regression instead of each GN iteration step, the higher measurement accuracy of a nanostructure can be achieved. The remarkably improved reconstruction of a deep-etched multilayer grating has demonstrated the feasibility of the proposed method.

Paper Details

Date Published: 19 March 2015
PDF: 8 pages
Proc. SPIE 9424, Metrology, Inspection, and Process Control for Microlithography XXIX, 94240Y (19 March 2015); doi: 10.1117/12.2086058
Show Author Affiliations
Jinlong Zhu, Huazhong Univ. of Science and Technology (China)
Hao Jiang, Huazhong Univ. of Science and Technology (China)
Chuanwei Zhang, Huazhong Univ. of Science and Technology (China)
Xiuguo Chen, Huazhong Univ. of Science and Technology (China)
Shiyuan Liu, Huazhong Univ. of Science and Technology (China)


Published in SPIE Proceedings Vol. 9424:
Metrology, Inspection, and Process Control for Microlithography XXIX
Jason P. Cain; Martha I. Sanchez, Editor(s)

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