Stable dielectric fracture at interconnects from electromigration stresses Original Research Article

An analysis is developed for fracture of the constraining dielectric adjacent to a conducting line undergoing electromigration in a microelectronic interconnection structure. The crack driving force associated with the electromigration-induced stress exhibits a destabilizing-to-stabilizing transition, corresponding to an initiation–propagation–arrest sequence for fracture in the dielectric. This sequence derives from the inclusion in the fracture kinetics of the dielectric of the zero-velocity threshold. A feature of the analysis is the competing time scales for development of the electromigration stress and for non-equilibrium crack extension. The model is applied to three dielectric systems incorporating an Al line in conventional SiO2 and Al and Cu lines in a low-k silsesquioxane material.