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Title: Dual-domain lateral shearing interferometer

Abstract

The phase-shifting point diffraction interferometer (PS/PDI) was developed to address the problem of at-wavelength metrology of extreme ultraviolet (EUV) optical systems. Although extremely accurate, the fact that the PS/PDI is limited to use with coherent EUV sources, such as undulator radiation, is a drawback for its widespread use. An alternative to the PS/PDI, with relaxed coherence requirements, is lateral shearing interferometry (LSI). The use of a cross-grating, carrier-frequency configuration to characterize a large-field 4.times.-reduction EUV lithography optic is demonstrated. The results obtained are directly compared with PS/PDI measurements. A defocused implementation of the lateral shearing interferometer in which an image-plane filter allows both phase-shifting and Fourier wavefront recovery. The two wavefront recovery methods can be combined in a dual-domain technique providing suppression of noise added by self-interference of high-frequency components in the test-optic wavefront.

Inventors:
;
Publication Date:
Research Org.:
Univ. of California, Oakland, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1174776
Patent Number(s):
6,707,560
Application Number:
09/632,631
Assignee:
University Of California, The Regents Of
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION

Citation Formats

Naulleau, Patrick P., and Goldberg, Kenneth Alan. Dual-domain lateral shearing interferometer. United States: N. p., 2004. Web.
Naulleau, Patrick P., & Goldberg, Kenneth Alan. Dual-domain lateral shearing interferometer. United States.
Naulleau, Patrick P., and Goldberg, Kenneth Alan. Tue . "Dual-domain lateral shearing interferometer". United States. https://www.osti.gov/servlets/purl/1174776.
@article{osti_1174776,
title = {Dual-domain lateral shearing interferometer},
author = {Naulleau, Patrick P. and Goldberg, Kenneth Alan},
abstractNote = {The phase-shifting point diffraction interferometer (PS/PDI) was developed to address the problem of at-wavelength metrology of extreme ultraviolet (EUV) optical systems. Although extremely accurate, the fact that the PS/PDI is limited to use with coherent EUV sources, such as undulator radiation, is a drawback for its widespread use. An alternative to the PS/PDI, with relaxed coherence requirements, is lateral shearing interferometry (LSI). The use of a cross-grating, carrier-frequency configuration to characterize a large-field 4.times.-reduction EUV lithography optic is demonstrated. The results obtained are directly compared with PS/PDI measurements. A defocused implementation of the lateral shearing interferometer in which an image-plane filter allows both phase-shifting and Fourier wavefront recovery. The two wavefront recovery methods can be combined in a dual-domain technique providing suppression of noise added by self-interference of high-frequency components in the test-optic wavefront.},
doi = {},
url = {https://www.osti.gov/biblio/1174776}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2004},
month = {3}
}

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