The determination for the adhesion of film and substrate by surface acoustic waves

Layered film structures are widely applied in industry. The adhesion of thin film, which controls the product quality, is a key factor to be known before being used. The possibility of applying the surface acoustic waves (SAWs) technique to determine the adhesion of film and substrate is explored by a theoretical approach. The adhesion of interface is modeled by a spring boundary model. A commonly used structure of low-k film deposited on Si substrate in semiconductor industry is taken as an example. Theoretical results show that the SAWs dispersion curves are well separated for the distributed spring constants from 0.05 TPa to 5 TPa, which correspond to the poorly bonded and perfectly bonded interface, respectively. The results confirm that the SAWs technique has a high resolution on determining the adhesion property of film and substrate nondestructively.