Article: Spectroscopic ellipsometry and polarimetry for materials and systems analysis at the nanometer scale: state-of-the-art, potential, and perspectives.Maria Losurdo, Michael Bergmair, Giovanni Bruno, Denis Cattelan, Christoph Cobet, Antonello de Martino, Karsten Fleischer, Zorana Dohcevic-Mitrovic, Norbert Esser, Melanie Galliet, Rados Gajic, Dušan Hemzal, Kurt Hingerl, Josef Humlicek, Razvigor Ossikovski, Zoran V Popovic, Ottilia Saxl[show abstract] [hide abstract]
ABSTRACT: This paper discusses the fundamentals, applications, potential, limitations, and future perspectives of polarized light reflection techniques for the characterization of materials and related systems and devices at the nanoscale. These techniques include spectroscopic ellipsometry, polarimetry, and reflectance anisotropy. We give an overview of the various ellipsometry strategies for the measurement and analysis of nanometric films, metal nanoparticles and nanowires, semiconductor nanocrystals, and submicron periodic structures. We show that ellipsometry is capable of more than the determination of thickness and optical properties, and it can be exploited to gain information about process control, geometry factors, anisotropy, defects, and quantum confinement effects of nanostructures.Journal of Nanoparticle Research 10/2009; 11(7):1521-1554. · 3.29 Impact Factor
Patent: Device and method for taking spectroscopic polarimetric measurements in the visible and near-infrared rangesRef. No: WO2009FR52087, Year: 01/2009
Article: Comparison of spectroscopic Mueller polarimetry, standard scatterometry, and real space imaging techniques (SEM and 3D-AFM) for dimensional characterization of periodic structuresA De Martino, M Foldyna, T Novikova, D Cattelan, P Barritault, C Licitra, J Hazart, J Foucher, F Bogeat[show abstract] [hide abstract]
ABSTRACT: Spectroscopic Mueller polarimetry may provide a useful alternative to standard spectroscopic ellipsometry (SE) for the dimensional characterization of periodic structures, as it provides 16 quantities instead of 2 for SE. We present a detailed experimental comparison of the results provided by conventional scatterometry (0.7 - 5 eV) spectral range), Mueller polarimetry in the visible (450 - 825 nm), electron microscopy (top CD-SEM and cross section) and state-of-the-art CDAFM (Veeco X3D). This last instrument was considered as the best reference currently available. The samples were 1D gratings etched in bulk Si, with 150 and 250 nm nominal CDs and several pitches for each CD. SE spectra were taken at zero azimuthal angles (i.e. with the grooves perpendicular to the incidence plane), as it is usually done with standard scatterometers, while Mueller spectra were measured at all azimuths in steps of 5°, allowing significant consistency tests by comparing the results of the corresponding fits. Both techniques provided CD values in agreement with AFM and CD-SEM data to within 5 nm, comparable to the AFM precision. Grating thickness and sidewall angle (SWA) were best determined by Mueller polarimetry at 90° azimuth, while in the usual zero azimuth configuration, SWA was typically underestimated by several degrees.Proc SPIE 01/2008; 7140:69221P-69221P-8.
Conference Proceeding: Characterization of gratings by Mueller polarimetry in conical diffraction[show abstract] [hide abstract]
ABSTRACT: Spectroscopic Ellipsometry is widely used to characterize 1D gratings in the usual planar diffraction geometry, with grating grooves perpendicular to the incidence plane. The Jones matrix of the grating is then diagonal, and it can be measured properly by any conventional ellipsometer. On the other hand, if the grating is measured at different azimuthal angles, i.e. in conical diffraction geometries, its Jones matrix is no longer diagonal. As a result, additional information is available about the grating groove shape, but a generalized ellipsometer, or a Mueller polarimeter, are necessary to retrieve this information completely. We used this approach with photoresist gratings deposited on Si for nominal CDs down to 70 nm. The instrument was an original Mueller polarimeter based on ferroelectric liquid crystals, and operated in the visible. The measured spectra were fitted with a RCWA code suitable for conical diffraction, with rectangular and trapezoidal profiles. This approach proved to greatly reduce the parameter correlations observed with standard SE for very small CDs. The relevance of the trapezoidal profile can be established, and top and bottom CDs can be "disentangled" much more easily than with standard planar diffraction geometrySPIE Metrology, Inspection, and Process Control for Microlithography XIX, San Jose, USA; 05/2005
Conference Proceeding: Characterization of inhomogeneous samples by spectroscopic Mueller polarimetry[show abstract] [hide abstract]
ABSTRACT: Light depolarization occurs whenever different polarization responses add up incoherently, as it may be the case with inhomogeneous samples. The most convenient technique to characterize such samples is Mueller matrix polarimetry, as it is the only one providing all the relevant information in presence of depolarization. We studied the case of small grating boxes surrounded by bare silicon, in conditions where both the gratings and the substrate were illuminated by the Mueller polarimeter beam. The grating optical response is modeled by using rigorous coupled-waves analysis, and added incoherently to that of the substrate by merely summing the corresponding Mueller matrices. The line width and the depth of the grating as well as the percentage of substrate in irradiated spot area were obtained by fitting the experimental data taken with controlled displacement of the light spot in the boundary region between grating and substrate. Accurate grating parameters could be obtained with the fraction of the spot area within the grating box was larger than 30%. Moreover, these parameters remained relatively constant when this fraction was further decreased to 5%.LITHOGRAPHY ASIA 2008; 01/2008
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