Determination of residual stress and interface adhesion toughness of thin films by blisters

Abstract

Circular blisters and telephone cord blisters (TCBs) can spontaneously occur in thin films under constant bi-axial compressive residual stress. In this work, new mechanical models are used in conjunction with measurements of blister morphology parameters to determine the residual stress in films and the adhesion toughness at interfaces. These new models are based on the hypothesis that pockets of energy concentration (PECs) drive the nucleation and growth of blisters instead of buckling, as in the conventional models, since the thin films are under constant compressive residual stress. Predictions from the models are in excellent agreement with independent experimental data.