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Proceedings Paper

Comparison techniques for VSB fractured vs. unfractured data
Author(s): D. Salazar; J. Valadez
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Paper Abstract

There are known VSB (Variable shape beam) mask writers in production today that require mask data with all angle edges to be approximated by staircases (stacked slits) in either a horizontal or vertical direction. The approximation uses 0, 45 or 90 degree edges, depending on the fracture setup and the angle of the edges in the original data. In order to gauge the effectiveness of the algorithm that fractures the original design to the VSB format, several methods can be employed to analyze the differences between the fractured data in the VSB format output and the original data before fracture. This is commonly referred to as skew error. This paper explores various methods and approaches that can be used, and examines each in detail. The goal is to highlight the differences and the effectiveness of each method in order to provide mask makers with the necessary information to make decisions best suited for their MDP-to-Lithography process flow. The first method explored is an XOR operation, followed by a double geometric biasing, aka Underover Sizing. The second method explored is an XOR operation, followed by a cut out of the differences starting from the unfractured polygon edges, aka Path Implode. The third method analyzed is an XOR operation, followed by measurement of the differences in the direction orthogonal to the unfractured edges, aka Difference Measurement. The fourth and last method analyzed is a mix of the last two, and employs an XOR operation, followed by measurement of the differences in the direction orthogonal to the unfractured edges, followed by a cut out of the measurement results, aka Measurement Implode.

Paper Details

Date Published: 28 June 2013
PDF: 10 pages
Proc. SPIE 8701, Photomask and Next-Generation Lithography Mask Technology XX, 87010F (28 June 2013); doi: 10.1117/12.2027339
Show Author Affiliations
D. Salazar, Synopsys, Inc. (United States)
J. Valadez, Synopsys, Inc. (United States)


Published in SPIE Proceedings Vol. 8701:
Photomask and Next-Generation Lithography Mask Technology XX
Kokoro Kato, Editor(s)

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