Change of the failure mode of layered aluminum conductors by modification of overlying dielectric

The failure mode of multilayered Al interconnects changes from shorts due to extrusions to failures due to resistance increase when the overlying dielectric is modified. A thick rigid dielectric favors failures due to extrusions whereas a more flexible dielectric favors resistance increase. The dielectric effectively changes the mechanical behavior of the interconnect without changing the overall kinetics of mass accumulation and depletion and suggests a model where the final mode of failure is determined by the response of the interconnect to mechanical stresses.<>