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Proceedings Paper

High-precision optical heterodyne interferometric dilatometer for determining absolute CTE of EUVL materials
Author(s): Yoshimasa Takeichi; Iwao Nishiyama; Naofumi Yamada
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Paper Abstract

The low-thermal-expansion materials (LTEMs) used in extreme ultraviolet lithography (EUVL) must have an ultralow coefficient of thermal expansion (CTE) on the order of 10-9 K-1. Unfortunately, the resolution of commercial dilatometers is too low to accurately measure the properties of LTEMs for EUVL. So, we have developed a practical dilatometer tailored to meet EUVL requirements. It is based on the double-path heterodyne interferometer technology developed by AIST. This technology has the advantage of providing absolute CTE measurements, which means direct measurement of the change in specimen length with an interferometer. The design of the dilatometer has been optimized to yield high-precision measurements, and it should enable displacement measurements to be made with a resolution of better than one nanometer.

Paper Details

Date Published: 6 May 2005
PDF: 8 pages
Proc. SPIE 5751, Emerging Lithographic Technologies IX, (6 May 2005); doi: 10.1117/12.599400
Show Author Affiliations
Yoshimasa Takeichi, Association of Super-Advanced Electronics Technologies (Japan)
Iwao Nishiyama, Association of Super-Advanced Electronics Technologies (Japan)
Naofumi Yamada, National Institute of Advanced Industrial Science and Technology (Japan)
National Metrology Institute of Japan (Japan)

Published in SPIE Proceedings Vol. 5751:
Emerging Lithographic Technologies IX
R. Scott Mackay, Editor(s)

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