Phenomena such as electromigration and stress-induced migration occurring in metal interconnects of devices such as integrated circuits are inhibited by use of underlying non-planarities. Thus the material underlying the interconnect is formed to have non-planarities typically of at least 0.02 μm in height and advantageously within 100 μm of another such non-planarity. Such non-planarities, it is contemplated, reduce grain boundary movement in the overlying interconnect with a concomitant reduction in void aggregation.