Aluminum Stress Migration

A failure mechanism in semiconductor devices. The term stress migration describes the movement of metal atoms under the influence of mechanical stress gradients. Generally, stress gradients can be assumed to be proportional to the applied mechanical stress. Vacancies diffuse from sites of small hydrostatic stress to high stress regions to effect metal movement. Flux divergence associated with the metal movement causes voiding in the ULSI metal leads. The resistance rise associated with the void formation may cause electrical failures. (Reference JEP122F)