The adhesive strength of ceramic - copper interfaces was measured in four point bending using a central notch for crack initiation. According to our method, plastic deformation may occur during the delamination process. FEM simulations were employed in order to separate elastic and plastic contributions to the energy consumption of the experiment. In conclusion, a novel delamination criterion based on the stress intensity at the crack tip was established. Here, the stress invariant J3is used as indicator for delamination of the interface. Agreement between experiments and theoretical interpretation is demonstrated for copper layers directly bonded to aluminum oxide.
Interface States Characterization of UTB SOI MOSFETs From the Subthreshold Current