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Proceedings Paper

A comparison of advanced overlay technologies
Author(s): Prasad Dasari; Nigel Smith; Gary Goelzer; Zhuan Liu; Jie Li; Asher Tan; Chin Hwee Koh
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Paper Abstract

The extension of optical lithography to 22nm and beyond by Double Patterning Technology is often challenged by CDU and overlay control. With reduced overlay measurement error budgets in the sub-nm range, relying on traditional Total Measurement Uncertainty (TMU) estimates alone is no longer sufficient. In this paper we will report scatterometry overlay measurements data from a set of twelve test wafers, using four different target designs. The TMU of these measurements is under 0.4nm, within the process control requirements for the 22nm node. Comparing the measurement differences between DBO targets (using empirical and model based analysis) and with image-based overlay data indicates the presence of systematic and random measurement errors that exceeds the TMU estimate.

Paper Details

Date Published: 1 April 2010
PDF: 9 pages
Proc. SPIE 7638, Metrology, Inspection, and Process Control for Microlithography XXIV, 76381P (1 April 2010); doi: 10.1117/12.848189
Show Author Affiliations
Prasad Dasari, Nanometrics Inc. (United States)
Nigel Smith, Nanometrics Inc. (United States)
Gary Goelzer, Nanometrics Inc. (United States)
Zhuan Liu, Nanometrics Inc. (United States)
Jie Li, Nanometrics Inc. (United States)
Asher Tan, Nanometrics Inc. (United States)
Chin Hwee Koh, Nanometrics Inc. (United States)

Published in SPIE Proceedings Vol. 7638:
Metrology, Inspection, and Process Control for Microlithography XXIV
Christopher J. Raymond, Editor(s)

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