Patent ID: 9442063
Filing Date: 2016-09-13
CPC Classification: G01N

Claim Text:
1. A method comprising: generating, with one or more processors, a three-dimensional design of experiment (DOE) for a plurality of wafers, a first dimension of the DOE being a relative amount of a first component of a thin film, a second dimension of the DOE being a relative amount of a second component of the thin film, a third dimension of the DOE being a thickness of the thin film; acquiring, with an ellipsometer, a spectrum for each of the wafers across a selected spectral range; generating, with the one or more processors, a series of optical dispersion data by extracting a real component (n) of a complex index of refraction and an imaginary component (k) of the complex index of refraction across the selected spectral range for each of the acquired spectrum utilizing a regression process applied to a selected dispersion model; identifying, with the one or more processors, one or more systematic trends within the series of optical dispersion data acquired from the plurality of wafers as a function of at least one of the first dimension, the second dimension or the third dimension, wherein the one or more systematic trends in the series of optical dispersion data are characterized by at least one of a rotation parameter; and generating, with the one or more processors, a multi-component Bruggeman effective medium approximation (BEMA) model utilizing the identified one or more systematic trends characterized by at least one of the rotation parameter within the series of optical dispersion data acquired from the plurality of wafers as a function of at least one of the first dimension, the second dimension or the third dimension and the generated series of optical dispersion data acquired from the plurality of wafers.