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Proceedings Paper

Developing an uncertainty analysis for optical scatterometry
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Paper Abstract

This article describes how an uncertainty analysis may be performed on a scatterometry measurement. A method is outlined for propagating uncertainties through a least-squares regression. The method includes the propagation of the measurement noise as well as estimates of systematic effects in the measurement. Since there may be correlations between the various parameters determined by the measurement, a method is described for visualizing the uncertainty in the extracted profile. The analysis is performed for a 120 nm pitch grating, consisting of photoresist lines 120 nm high, 45 nm critical dimension, and 88° side wall angle, measured with a spectroscopic rotating compensator ellipsometer. The results suggest that, while scatterometry is very precise, there are a number of sources of systematic errors that limit its absolute accuracy. Addressing those systematic errors may significantly improve scatterometry measurements in the future.

Paper Details

Date Published: 23 March 2009
PDF: 11 pages
Proc. SPIE 7272, Metrology, Inspection, and Process Control for Microlithography XXIII, 72720T (23 March 2009); doi: 10.1117/12.814835
Show Author Affiliations
Thomas A. Germer, National Institute of Standards and Technology (United States)
Heather J. Patrick, National Institute of Standards and Technology (United States)
KT Consulting, Inc. (United States)
Richard M. Silver, National Institute of Standards and Technology (United States)
Benjamin Bunday, SEMATECH, Inc. (United States)


Published in SPIE Proceedings Vol. 7272:
Metrology, Inspection, and Process Control for Microlithography XXIII
John A. Allgair; Christopher J. Raymond, Editor(s)

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