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Proceedings Paper

Dispersion-controlled low-coherent interferometry for thin-film characterization
Author(s): M. Preuß; Ch. Taudt; B. Nelsen; P. Hartmann
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Paper Abstract

In this work, a novel experimental procedure for thin-film characterization and its data analysis is described. The presented technique is based on low-coherence interferometry and resolves thicknesses with nm-precision. An element with known dispersion is placed in the interferometer's sample arm and delivers a controlled phase variation in relation to the wavelength. This phase variation is dependent on the thickness of the material and its wavelength-dependent refractive index. Furthermore, the phase variation is characterized by a stationary point, the so called equalization wavelength. Changes in the thickness of the material under test will shift the equalization wavelength and transform its interference amplitude. In combination with an imaging spectrometer thin films are spatially resolved with a spatial resolution of 4 μm within a single acquisition. This makes data acquisition fast. The advantage over other conventionally used methods, like reflectometry and ellipsometry, is that signal processing is greatly simplified and therefore much faster.

Paper Details

Date Published: 24 May 2018
PDF: 8 pages
Proc. SPIE 10678, Optical Micro- and Nanometrology VII, 106780R (24 May 2018); doi: 10.1117/12.2307166
Show Author Affiliations
M. Preuß, Westsächsische Hochschule Zwickau (Germany)
Fraunhofer-Institut für Werkstoff- und Strahltechnik (Germany)
Ch. Taudt, Westsächsische Hochschule Zwickau (Germany)
Fraunhofer-Institut für Werkstoff- und Strahltechnik (Germany)
Technische Univ. Dresden (Germany)
B. Nelsen, Westsächsische Hochschule Zwickau (Germany)
Fraunhofer-Institut für Werkstoff- und Strahltechnik (Germany)
P. Hartmann, Westsächsische Hochschule Zwickau (Germany)
Fraunhofer-Institut für Werkstoff- und Strahltechnik (Germany)


Published in SPIE Proceedings Vol. 10678:
Optical Micro- and Nanometrology VII
Christophe Gorecki; Anand Krishna Asundi; Wolfgang Osten, Editor(s)

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