Chapter IV - Mechanical Properties

Abstract

This chapter discusses mechanical properties of thin films; and the interface between film and substrate. The mechanical properties of thin films include: (1) flow strength; (2) fracture strengths of film and of interface between film and substrate; (3) friction and resistance to wear, elastic moduli, stress relaxation; and (4) piezoelectric properties. The mechanical properties of thin films affect their behavior in a variety of applications: (1) the plastic flow and fracture that occur during the operation of conductor lines upon electro-migration induced stress development are affected by the mechanical properties of the film as well as the mechanical constraints provided by the substrate and cladding; (2) adhesion of film to substrate is affected by the film's mechanical properties as well as the substrate/ film interface strength; and (3) wear of thin film head and recording media thin film over layers depend upon their mechanical properties. The chapter briefly reviews the fracture mechanics of the delamination process, the resistance of the interface to delamination, and the effect of interface structure on interface fracture.