Proceedings Article | 13 May 2013
KEYWORDS: Scatterometry, Optimization (mathematics), Inverse problems, Refractive index, Neural networks, Metrology, Lithography, Diffraction, Process control, Data modeling
S-Genius is a new universal scatterometry platform, which gathers all the LTM-CNRS know-how regarding the rigorous
electromagnetic computation and several inverse problem solver solutions. This software platform is built to be a userfriendly,
light, swift, accurate, user-oriented scatterometry tool, compatible with any ellipsometric measurements to fit
and any types of pattern. It aims to combine a set of inverse problem solver capabilities — via adapted Levenberg-
Marquard optimization, Kriging, Neural Network solutions — that greatly improve the reliability and the velocity of the
solution determination. Furthermore, as the model solution is mainly vulnerable to materials optical properties, S-Genius
may be coupled with an innovative material refractive indices determination. This paper will a little bit more focuses on
the modified Levenberg-Marquardt optimization, one of the indirect method solver built up in parallel with the total SGenius
software coding by yours truly. This modified Levenberg-Marquardt optimization corresponds to a Newton
algorithm with an adapted damping parameter regarding the definition domains of the optimized parameters.
Currently, S-Genius is technically ready for scientific collaboration, python-powered, multi-platform
(windows/linux/macOS), multi-core, ready for 2D- (infinite features along the direction perpendicular to the incident
plane), conical, and 3D-features computation, compatible with all kinds of input data from any possible ellipsometers
(angle or wavelength resolved) or reflectometers, and widely used in our laboratory for resist trimming studies, etching
features characterization (such as complex stack) or nano-imprint lithography measurements for instance. The work
about kriging solver, neural network solver and material refractive indices determination is done (or about to) by other
LTM members and about to be integrated on S-Genius platform.
