In this study, we developed a system allowing interfacial adhesionmeasurements as a function of mode-mixity, from pure tension to pure shear.Results show that the debonding energy increases, by a factor of 3 to 10, asthe amount of shear stress increases, approaching mode II conditions. Forlow k dielectrics, the debonding energy was found to decrease withincreasing porosity and increase with increasing plasticity. The crackpropagation is also dependent on mode-mixity.