Patent ID: 6081330
Filing Date: 2000-06-27
Classification: G01B,G01N

Abstract:
A method for determining the thickness of a thin metal film which forms part of a sample at more than one location, the method comprising:exciting time-dependent acoustic waveguide modes in the sample at a first location by directing an excitation radiation field defined by a wavevector onto the sample,detecting the acoustic waveguide modes in the first location by diffracting probe radiation off a ripple morphology induced on the sample's surface by the acoustic waveguide modes,analyzing the diffracted probe radiation to measure at least one velocity or frequency of the acoustic waveguide modes,determining the thickness of the thin metal film in the first location from the measured phase velocity or frequency, andrepeating the exciting, detecting, and analyzing steps at one or more additional locations on the sample to determine the thickness of the thin metal film from the measured phase velocity or frequency in the one or more additional locations.