Morphology of corrosion pits in aluminum thin film metallizations

The morphology of corrosion pits in sputtered pure aluminum and Al(0.5 wt% Cu) thin film metallizations has been investigated for a diluted chloride solution. The observed fractal-like patterns show clearly distinct features in ramification and branch density, which can be attributed to microscopic inhomogeneities inside the aluminum film. It is discussed how these observations may have an impact on the current description of diffusion phenomena in thin films, e.g. concerning electromigration.