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Proceedings Paper

Measurement of the surface shape and optical thickness variation of a polishing crystal wafer by wavelength tuning interferometer
Author(s): Yangjin Kim; Kenichi Hibino; Ryohei Hanayama; Naohiko Sugita; Mamoru Mitsuishi
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Paper Abstract

Interferometric surface measurement of parallel plates presents considerable technical difficulties owing to multiple beam interference. To apply the phase-shifting technique, it is necessary to use an optical-path-difference-dependent technique such as wavelength tuning that can separate interference signals in the frequency domain. In this research, the surface shape and optical thickness variation of a lithium niobate wafer for a solid Fabry-Perot etalon during the polishing process were measured simultaneously using a wavelength-tuning Fizeau interferometer with a novel phase shifting algorithm. The novel algorithm suppresses the multiple beam interference noise and has sidelobes with amplitudes of only 1% of that of the main peak. The wafer, which was in contact with a supporting glass parallel plate, generated six different interference fringes that overlapped on the detector. Wavelength-tuning interferometry was employed to separate the specific interference signals associated with the target different optical paths in the frequency domain. Experimental results indicated that the optical thickness variation of a circular crystal wafer 74 mm in diameter and 5-mm thick was measured with an uncertainty of 10 nm PV.

Paper Details

Date Published: 1 May 2014
PDF: 8 pages
Proc. SPIE 9132, Optical Micro- and Nanometrology V, 91320V (1 May 2014); doi: 10.1117/12.2051193
Show Author Affiliations
Yangjin Kim, The Univ. of Tokyo (Japan)
Kenichi Hibino, National Institute of Advanced Industrial Science and Technology (Japan)
Ryohei Hanayama, Graduate School for the Creation of New Photonics Industries (Japan)
Naohiko Sugita, The Univ. of Tokyo (Japan)
Mamoru Mitsuishi, The Univ. of Tokyo (Japan)

Published in SPIE Proceedings Vol. 9132:
Optical Micro- and Nanometrology V
Christophe Gorecki; Anand Krishna Asundi; Wolfgang Osten, Editor(s)

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