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Unbiased Estimation of Linewidth Roughness

Published

Author(s)

John S. Villarrubia, B Bunday

Abstract

Line width roughness (LWR) is usually estimated simply as three standard deviations of the line width. The effect of image noise upon this metric includes a positive nonrandom component. The metric is therefore subject to a bias or ?systematic error? that we have estimated can be comparable in size to the roughness itself for samples as smooth as required by the industry roadmap. We illustrate the problem using scanning electron microscope images of rough lines. We propose simple changes to the measurement algorithm that, if adopted by metrology instrument suppliers, would permit estimation of LWR without bias caused by image noise. (11 references)
Proceedings Title
Proceedings of SPIE
Volume
5752
Conference Dates
February 27-March 4, 2005
Conference Location
San Jose, CA, USA
Conference Title
Metrology, Inspection, and Process Control for Microlithography XIX, Richard M. Silver, Editor, May 2005

Keywords

line edge roughness (LER), line width roughness (LWR), measurement algorithms, measurement bias, Scanning Electron Microscopy (SEM)

Citation

Villarrubia, J. and Bunday, B. (2005), Unbiased Estimation of Linewidth Roughness, Proceedings of SPIE, San Jose, CA, USA, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=822373 (Accessed December 4, 2024)

Issues

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Created April 30, 2005, Updated October 12, 2021