title: Laser generated guided waves and finite element modeling for the thickness gauging of thin layers.
abstract: In this paper, nondestructive testing has been performed on a thin gold layer deposited on a 2 in. silicon wafer. Guided waves were generated and studied using a laser ultrasonic setup and a two-dimensional fast Fourier transform technique was employed to obtain the dispersion curves. A gold layer thickness of 1.33 microm has been determined with a +/-5% margin of error using the shape of the two first propagating modes, assuming for the substrate and the layer an uncertainty on the elastic parameters of +/-2.5%. A finite element model has been implemented to validate the data post-treatment and the experimental results. A good agreement between the numerical simulation, the analytical modeling and the experimentations has been observed. This method was considered suitable for thickness layer higher than 0.7 microm.
authors.affiliation: Département Opto-Acousto-Electronique (UMR CNRS 8520), Institut d'Electronique de Microélectronique et de Nanotechnologie, Université de Valenciennes, Le Mont Houy, 59313 Valenciennes Cedex 09, France.
authors.forename: F
authors.initials: F
authors.lastname: Lefevre
authors.forename: F
authors.initials: F
authors.lastname: Jenot
authors.forename: M
authors.initials: M
authors.lastname: Ouaftouh
authors.forename: M
authors.initials: M
authors.lastname: Duquennoy
authors.forename: M
authors.initials: M
authors.lastname: Ourak