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Proceedings Paper

Modeling of focus blur in the context of optical proximity correction
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Paper Abstract

The concept of focus blur encompasses the effect of laser bandwidth longitudinal chromatic aberration and scanner stage vertical vibration. The finite bandwidth of excimer laser source causes a corresponding finite distribution of focal planes in a range of 100nm or larger for the optical lithography system. Similarly, scanner vertical stage vibration puts the wafer in a finite distribution of focal planes. Both chromatic aberration and vertical stage vibration could introduce significant CD errors, hence can no longer be ignored in current lithography processes development and OPC development that require CD control within a few nanometers. We developed several methodologies to model the laser chromatic aberration and vertical stage vibration in OPC (Optical Proximity Correction) modeling tool. Extensive simulations were done to calculate chromatic aberration and vertical stage vibration focus blur's impact on lithography patterning for a variety of test structures. Chromatic aberration and vertical stage vibration focus blur effect was further included as an regression term in experimental OPC model calibration to capture its impact on litho patterning, and significant benefit to OPC model calibration was observed.

Paper Details

Date Published: 7 March 2008
PDF: 9 pages
Proc. SPIE 6924, Optical Microlithography XXI, 69243K (7 March 2008);
Show Author Affiliations
Qiaolin Zhang, Synopsys, Inc. (United States)
Hua Song, Synopsys, Inc. (United States)
Kevin Lucas, Synopsys, Inc. (United States)
James Shiely, Synopsys, Inc. (United States)

Published in SPIE Proceedings Vol. 6924:
Optical Microlithography XXI
Harry J. Levinson; Mircea V. Dusa, Editor(s)

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