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Proceedings Paper

Picosecond ultrasonic characterization of Mo/Si multilayers for extreme ultraviolet lithography
Author(s): Nen-Wen Pu; Seongtae Jeong; Rian Zhao; Jeffrey Bokor
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Paper Abstract

We have used picosecond ultrasonic techniques as a nondestructive detection tool to characterize Mo/Si multilayer reflectors for EUV. The lowest two localized acoustic-phonon surface modes were simultaneously observed in our samples with various d and (Gamma) values. The vibration frequencies of these surface modes depend both on d and (Gamma) , and can be used to extract these two parameters. We mapped the thickness profile of a linearly graded Mo/Si multilayer sample with 2 percent d-variation from the two edges towards the center. The dependence of the vibration frequencies on (Gamma) was also studied theoretically and experimentally, and was found to be separable from the dependence on d.

Paper Details

Date Published: 25 June 1999
PDF: 8 pages
Proc. SPIE 3676, Emerging Lithographic Technologies III, (25 June 1999); doi: 10.1117/12.351136
Show Author Affiliations
Nen-Wen Pu, Univ. of California/Berkeley (United States)
Seongtae Jeong, Lawrence Berkeley National Lab (United States)
Rian Zhao, Univ. of California/Berkeley (United States)
Jeffrey Bokor, Univ. of California/Berkeley (United States)

Published in SPIE Proceedings Vol. 3676:
Emerging Lithographic Technologies III
Yuli Vladimirsky, Editor(s)

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