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Proceedings Paper

Improving aberration control with application specific optimization using computational lithography
Author(s): Jianming Zhou; Youping Zhang; Peter Engblom; Mike Hyatt; Eric Wu; Martin Snajdr; Anton deVilliers; Yuan He; Craig Hickman; Peng Liu; Dennis de Lang; Bernd Geh; Erik Byers; Scott Light
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Paper Abstract

As the industry drives to lower k1 imaging we commonly accept the use of higher NA imaging and advanced illumination conditions. The advent of this technology shift has given rise to very exotic pupil spread functions that have some areas of high thermal energy density creating new modeling and control challenges. Modern scanners are equipped with advanced lens manipulators that introduce controlled adjustments of the lens elements to counteract the lens aberrations existing in the system. However, there are some specific non-correctable aberration modes that are detrimental to important structures. In this paper, we introduce a methodology for minimizing the impact of aberrations for specific designs at hand. We employ computational lithography to analyze the design being imaged, and then devise a lens manipulator control scheme aimed at optimizing the aberration level for the specific design. The optimization scheme does not minimize the overall aberration, but directs the aberration control to optimize the imaging performance, such as CD control or process window, for the target design. Through computational lithography, we can identify the aberration modes that are most detrimental to the design, and also correlations between imaging responses of independent aberration modes. Then an optimization algorithm is applied to determine how to use the lens manipulators to drive the aberrations modes to levels that are best for the specified imaging performance metric achievable with the tool. We show an example where this method is applied to an aggressive memory device imaged with an advanced ArF scanner. We demonstrate with both simulation and experimental data that this application specific tool optimization successfully compensated for the thermal induced aberrations dynamically, improving the imaging performance consistently through the lot.

Paper Details

Date Published: 3 March 2010
PDF: 12 pages
Proc. SPIE 7640, Optical Microlithography XXIII, 76400K (3 March 2010); doi: 10.1117/12.846697
Show Author Affiliations
Jianming Zhou, Micron Technology, Inc. (United States)
Youping Zhang, Brion Technologies (United States)
Peter Engblom, ASML (United States)
Mike Hyatt, Micron Technology, Inc. (United States)
Eric Wu, Brion Technologies (United States)
Martin Snajdr, Brion Technologies (United States)
Anton deVilliers, Micron Technology, Inc. (United States)
Yuan He, Micron Technology, Inc. (United States)
Craig Hickman, Micron Technology, Inc. (United States)
Peng Liu, Brion Technologies (United States)
Dennis de Lang, ASML Netherlands B.V. (Netherlands)
Bernd Geh, Carl Zeiss SMT (United States)
Erik Byers, Micron Technology, Inc. (United States)
Scott Light, Micron Technology, Inc. (United States)

Published in SPIE Proceedings Vol. 7640:
Optical Microlithography XXIII
Mircea V. Dusa; Will Conley, Editor(s)

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