US Patent 7362453 Method for the characterization of a film

A method for the characterization of a film arranged in a plurality of regions on a substrate forms a respective optical measurement at each of a multiplicity of measurement sites in order to determine a respective measurement result, the measurement result being correlated with a film thickness on the substrate. Measurement results that satisfy a predetermined condition, which is satisfied for a measurement result that has been determined at a measurement site within one of the plurality of regions are selected. The film is characterized on the basis of the selected measurement results.