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Proceedings Paper

Calibration of CD-SEM: moving from relative to absolute measurements
Author(s): S. Babin; S. Borisov; A. Ivanchikov; I. Ruzavin
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Paper Abstract

CD-SEM measurement of linewidth, while providing good relative results, is not completely accurate. The measurements involve significant bias of the SEM signal at line edges. The bias varies depending on the SEM setup, the materials and profiles of patterns on the wafer, as well as charging. Existing methods of CD-SEM calibration are extremely limited, only being available for specific samples and materials. In this paper, simulations of SEM signal were carried out using advanced Monte Carlo models of electron interactions with samples. The linewidth was simulated for a variety of pattern materials and SEM setups. The corresponding linewidths were extracted. A CD bias was determined for each type of measurement. When a 3D pattern is exactly known in simulation, the SEM signal can be related to the pattern; then the bias can be found for any combination of SEM patterns. This has the potential to greatly improve CDSEM accuracy, toward the goal of absolute linewidth measurements.

Paper Details

Date Published: 24 March 2008
PDF: 8 pages
Proc. SPIE 6922, Metrology, Inspection, and Process Control for Microlithography XXII, 69222M (24 March 2008); doi: 10.1117/12.775104
Show Author Affiliations
S. Babin, Abeam Technologies, Inc. (United States)
S. Borisov, Abeam Technologies, Inc. (United States)
A. Ivanchikov, Abeam Technologies, Inc. (United States)
I. Ruzavin, Abeam Technologies, Inc. (United States)

Published in SPIE Proceedings Vol. 6922:
Metrology, Inspection, and Process Control for Microlithography XXII
John A. Allgair; Christopher J. Raymond, Editor(s)

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