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Proceedings Paper

Lateral shearing interferometry for high-resolution EUV optical testing
Author(s): Ryan Miyakawa; Patrick Naulleau
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Paper Abstract

Next generation EUV optical systems are moving to higher resolution optics to accommodate the smaller length scales targeted by the semiconductor industry. As the numerical apertures (NA) of the optics become larger, it becomes increasingly difficult to characterize aberrations, which broaden the point-spread function and thus limit the ultimate resolution of an optical system. Lateral shearing interferometry (LSI) provides an attractive alternative to conventional interferometric techniques such as point diffraction interferometry due to its experimental simplicity, stability, relaxed coherence requirements, and its ability to scale to high numerical apertures. In this paper we present an analytical solution to the LSI interferogram in various NA regimes. We demonstrate that systematic aberrations present in high NA interferograms due to grating distortion of the diffracted order angular spectrum are measurable and must be compensated for in the reconstruction algorithm.

Paper Details

Date Published: 8 April 2011
PDF: 6 pages
Proc. SPIE 7969, Extreme Ultraviolet (EUV) Lithography II, 796939 (8 April 2011); doi: 10.1117/12.881554
Show Author Affiliations
Ryan Miyakawa, Univ. of California, Berkeley (United States)
Lawrence Berkeley National Lab. (United States)
Patrick Naulleau, Lawrence Berkeley National Lab. (United States)

Published in SPIE Proceedings Vol. 7969:
Extreme Ultraviolet (EUV) Lithography II
Bruno M. La Fontaine; Patrick P. Naulleau, Editor(s)

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