Patent ID: 6399944
Filing Date: 2002-06-04
Classification: G01B

Abstract:
A method of measuring a thickness of a film of first composition formed over a material of a second composition, comprising the steps of:providing a plurality of reference samples, each having a film of said first composition and of known thickness formed over a material of said second composition; for each of said reference samples, measuring a secondary electron spectrum emitted therefrom by being excited by a type of primary radiation, thereby obtaining a plurality of reference secondary electron spectra, each reference spectrum identified with a film thickness and including energy regions dominated by inelastic scattering; for a test sample having a film of said first composition formed over a material of said secondary composition, measuring a second electron spectrum emitted therefrom by being excited by said type of primary radiation, thereby obtaining a test secondary electron spectrum including an energy region dominated by inelastic scattering; and by comparing one or more regions dominated by inelastic scattering in said test secondary electron spectrum with one or more regions dominated by inelastic scattering in said reference secondary electron spectra, determining a thickness of the film of the test sample.