Patent ID: 7307723
Filing Date: 2007-12-11
Classification: G01N

Abstract:
1. A method for optical characterization of at least one layer of material in an interval A of values taken by a function α of an optical wavelength λ, when λ varies in an interval of wavelengths, the at least one layer being created on a substrate, the method comprising: 1) carrying out a set of reflectometry and/or ellipsometry measurements over the interval A with ellipsometric and/or reflectometric devices and a spectrometer, the set of measurements leading to a measured spectrum, marked ψ, and choosing methods for calculating associated with a nature of the measurements and with a type of layer to be characterized; 2) choosing m initial values α 3) choosing m complex initial values of a complex refraction index n*=n+jk for the m points α 4) when m is not 1, choosing an interpolation law that allows calculating the refraction index n(α) of the material over the interval B, from the points (α 5) choosing M variable parameters, M being less than or equal to 2 m+1; 6) choosing an error function Er (ψ, 7) using a minimizing function of Er (ψ, 8) increasing the number m of initial values of the function α and returning to step 2).