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Two-dimensional low-coherence interferometry for the characterization of nanometer-wafer-topographies

 
: Taudt, Christopher; Baselt, Tobias; Nelsen, Bryan; Aßmann, Heiko; Greiner, Andreas; Koch, Edmund; Hartmann, Peter

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Fulltext urn:nbn:de:0011-n-4110250 (607 KByte PDF)
MD5 Fingerprint: bd21f9c6a15c4d420247cccb89d44e80
Copyright Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.
Created on: 01.05.2017


Gorecki, C. ; Society of Photo-Optical Instrumentation Engineers -SPIE-, Bellingham/Wash.:
Optical Micro- and Nanometrology VI : 5-7 April 2016, Brussels, Belgium
Bellingham, WA: SPIE, 2016 (Proceedings of SPIE 9890)
ISBN: 9781510601352
Paper 98900R, 7 pp.
Conference "Optical Micro- and Nanometrology" <6, 2016, Brussels>
Bundesministerium für Bildung und Forschung BMBF
03FH004PX3; Dispersionsmessplatz
English
Conference Paper, Electronic Publication
Fraunhofer IWS ()
dispersion based measurements; in-line characterization; interferometric measurement; low-coherence interferometry; optical metrology; surface profilometry

Abstract
Within this work a scan-free, low-coherence interferometry approach for surface profilometry with nm-precision is presented. The basic setup consist of a Michelson-type interferometer which is powered by a super-continuum light-source (Δλ= 400-1700 nm). The introduction of an element with known dispersion delivers a controlled phase variation which can be detected in the spectral domain and used to reconstruct height differences on a sample. In order to enable scan-free measurements, the interference signal is spectrally decomposed with a grating and imaged onto a two-dimensional detector. One dimension of this detector records spectral, and therefore height information, while the other dimension stores the spatial position of the corresponding height values. In experiments on a height standard, it could be shown that the setup is capable of recording multiple height steps of 101 nm over a range of 500 m with an accuracy of about 11.5 nm. Further experiments on conductive paths of a micro-electro-mechanical systems (MEMS) pressure sensor demonstrated that the approach is also suitable to precisely characterize nanometer-sized structures on production-relevant components. The main advantage of the proposed measurement approach is the possibility to collect precise height information over a line on a surface without the need for scanning. This feature makes it interesting for a production-accompanying metrology.

: http://publica.fraunhofer.de/documents/N-411025.html