Acoustic evaluation of the integrity of thin film structures

This paper explores the potential offered by high frequency acoustic microscopy for nondestructive, qualitative and quantitative characterization of thin (micron and submicron) films. Wave propagation modeling in soft thin film samples shows that multiple modes of surface waves can exist in soft thin film structures. Interface weakness modeling indicates that surface wave velocities are sensitive to interface conditions and that different modes have different levels of sensitivity to bond strength. Our new acoustic microscope experimental system will be able to measure experimental dispersion curves, and measure the surface wave velocity as a function of frequency.