DYNAMIC REMOVAL OF CORRELATION OF HIGHLY CORRELATED PARAMETERS FOR OPTICAL METROLOGY

摘要

A method for dynamically eliminating correlations of parameters with high correlation for optical metrology has been disclosed. An embodiment of the method includes the steps of determining, as a model of a structure, the model comprising a set of parameters, performing optical metrology measurements on the structure, comprising collecting spectral data on a hardware element, ; Dynamically eliminating the correlation of two or more parameters in the set of parameters during measurement of the structure, wherein the iteration of the dynamic removal of the correlation comprises: generating a Jacobian matrix of a set of parameters; Applying singular value decomposition of the Jacobian matrix; Selecting a subset of the parameter set; And calculating the direction of the parameter search based on a subset of the parameters. If the model does not converge, performing one or more additional iterations of dynamic removal of the correlation until the model converges; And when the model converges, reporting the measurement results.