3-D fracture mechanics analysis of multilayer thin film package

Various features of crack growth and decohesion in single and multilayer thin film packages are investigated using computational procedures and the results are presented in this paper. The major aim of this investigation is to identify and characterize the driving force for fracture, both in terms of its magnitude and deformation mode, which arises in a thin film structure due to thermal expansion mismatch loading. The emphasis is placed on the geometrical models which are close representations of a thin film package. Residual stresses develop within the structure when the package cools form elevated temperature, or during thermal cycling. New energy integrals are formulated to determine the strain energy release rate and stress intensity factor under such thermal loading conditions.