A METHOD FOR MODELING MEASUREMENT DATA OVER A SUBSTRATE AREA AND ASSOCIATED APPARATUSES

A method for modeling measurement data over a substrate area relating to a substrate in a lithographic process. The method includes obtaining measurement data relating to the substrate and performing a combined fitting to fit to the measurement data: at least a first interfield model which describes distortion over the substrate and a field distortion model which describes distortion within an exposure field; wherein either: the at least a first interfield model includes a radial basis function model or an elastic energy minimizing spline model; or the method further includes fitting a radial basis function model or an elastic energy minimizing spline model to a distortion residual of the combined fit of a different interfield model and the field distortion model.