Effects of annealing and electromigration on surface morphology of polycrystalline films

The capillarity‐induced surface mass transport has been extended to cases where there is a notch and/or a ridge on a bicrystal system. Changes in the surface morphology caused by capillarity‐induced and electromigration‐induced surface diffusions and grain boundary diffusions have been analyzed. Thermal grooving is shown to develop only when the initial slope of a notch on the crystal surface is less than γb/2γs (γb and γs are, respectively, the grain boundary and the surface Gibbs free energy) or when the initial surface contains a ridge at the grain boundary. The slope of the grooving profile is invariant with time but its depth develops as the one fourth power of time. Surface fluxes due to the electromigration origin change the morphology in an asymmetric manner, biased in the direction of the electron flow. When combined with fluxes from grain boundary diffusion, severe mass depletion and accumulation can occur, giving rise to characteristic electromigration damage of open circuit failures. Finally, ...