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Proceedings Paper

157-nm system test for high-NA lithographic lens systems
Author(s): Horst Schreiber; Paul G. Dewa; K. Hanford; Robert Ligenza; Lisa R. Rich; Paul Jay Tompkins
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Paper Abstract

The path to smaller semiconductor feature sizes demands that lens systems operate at higher numerical apertures and shorter wavelengths. Materials available for operation at shorter wavelengths, such as 157nm, exhibit properties that have strong wavelength dependence. Accurate characterization of lens performance must be done at the wavelength of use so as to include these effects. Measurement of optical system performance at 157nm brings with it the necessity to operate in an environment purged of gases and outgasing byproducts. This constraint coupled with increasingly tight tolerances necessary to meet the advancing requirements of the semiconductor industry raise the level of sophistication required of test set-ups. We present an interferometric set-up designed to meet these requirements. The set-up is designed to work with the very low temporal and spatial coherence typical of 157nm laser sources. These coherence properties are used advantageously, reducing coherent noise in the system and achieving high resolution, repeatability and accuracy simultaneously. Specialized instrumentation enables various error-separation techniques to be used. We now measure phase-retardance in the wavefront in order to characterize the error introduced by the intrinsic properties of the material. The combination of these features is required for 'at wavelength' optimization of 157nm lens systems.

Paper Details

Date Published: 30 July 2002
PDF: 11 pages
Proc. SPIE 4691, Optical Microlithography XV, (30 July 2002); doi: 10.1117/12.474556
Show Author Affiliations
Horst Schreiber, Corning Tropel Corp. (United States)
Paul G. Dewa, Corning Tropel Corp. (United States)
K. Hanford, Corning Tropel Corp. (United States)
Robert Ligenza, Corning Tropel Corp. (United States)
Lisa R. Rich, Corning Tropel Corp. (United States)
Paul Jay Tompkins, Corning Tropel Corp. (United States)

Published in SPIE Proceedings Vol. 4691:
Optical Microlithography XV
Anthony Yen, Editor(s)

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