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Proceedings Paper

Diffraction signature analysis methods for improving scatterometry precision
Author(s): Mike Littau; Darren Forman; Josh Bruce; Christopher J. Raymond; Steven G. Hummel
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Paper Abstract

Scatterometry is a fast, non-destructive critical dimension (CD) optical metrology technique based on the analysis of light scattered from a periodic array of features. With technological advances in manufacturing, semiconductor devices are made in ever shrinking geometries. In recent years, the ability of scatterometry metrology tools to measure these devices at a gage-capable level for parameters such as CD, thickness or profile has become more challenging. The focus of this research is to analyze the acquired diffraction signature and determine an optimum diffraction signature "scan path." An optimized scan path can result in higher precision, reduced development time, smaller pre-generated library databases and faster real-time optimization speeds. In this work, we will first review several methods for scan path selection and optimization. Our results indicate that the method choice can influence the scan path selection, and that some of the methods are complementary to one another. For example, one method, which we term orthogonal sensitivity, uses intelligent algorithms to select optimal scan path points based on enhancing single parameter sensitivity. While the method works well, it neglects parameter correlation effects. Thus, we will also review a method where correlation effects are considered. Finally, we will calculate and summarize the effectiveness of optimal scan path selection techniques using challenging lithography applications.

Paper Details

Date Published: 24 March 2006
PDF: 10 pages
Proc. SPIE 6152, Metrology, Inspection, and Process Control for Microlithography XX, 615236 (24 March 2006); doi: 10.1117/12.656729
Show Author Affiliations
Mike Littau, Accent Optical Technologies, Inc. (United States)
Darren Forman, Accent Optical Technologies, Inc. (United States)
Josh Bruce, Accent Optical Technologies, Inc. (United States)
Christopher J. Raymond, Accent Optical Technologies, Inc. (United States)
Steven G. Hummel, Accent Optical Technologies, Inc. (United States)

Published in SPIE Proceedings Vol. 6152:
Metrology, Inspection, and Process Control for Microlithography XX
Chas N. Archie, Editor(s)

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