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Proceedings Paper

Characterization of critical dimension uniformity through in-situ detection of aerial images in a scanner
Author(s): Stefan Hunsche; Michael J. Gassner; Yu Cao; Hsin Chang; Jeng-Horng Chen
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Paper Abstract

We introduce a novel in-scanner aerial image sampling technique using a sensor wafer that can be loaded into a production scanner to acquire data at the wafer plane, and under exact production conditions in terms of all optical settings and parameters of the actual scanner and an actual reticle. We demonstrate the applicability of this system to CD uniformity characterization of a production scanner in combination with a test reticle. CD estimates can be directly obtained from the image data by applying a fixed threshold, by employing a calibrated resist model to the sensor data, or by using the sensor data to accurately calibrate a complete lithography model. The linear response of the sensor provides complete information on the imaging process, and CD data can be immediately correlated to other image parameters, such as contrast, ILS, peak signal values, etc. We demonstrate the ability of the system to characterize CD variations and through-pitch curves, and to generate CD uniformity maps across the exposure field. We have extensively studied the repeatability and reproducibility of the system, and show its ability to detect changes in imaging performance over time in a production environment, differences between exposure tools, or different mask manufacturing processes.

Paper Details

Date Published: 24 March 2006
PDF: 11 pages
Proc. SPIE 6152, Metrology, Inspection, and Process Control for Microlithography XX, 61521Z (24 March 2006); doi: 10.1117/12.657343
Show Author Affiliations
Stefan Hunsche, Brion Technologies, Inc. (United States)
Michael J. Gassner, Brion Technologies, Inc. (United States)
Yu Cao, Brion Technologies, Inc. (United States)
Hsin Chang, Taiwan Semiconductor Manufacturing Co., Ltd. (Taiwan)
Jeng-Horng Chen, Taiwan Semiconductor Manufacturing Co., Ltd. (Taiwan)

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

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