Characterization of the Cu/barrier metal interface for copper interconnects

The Cu/barrier metal interface must be controlled to suppress interfacial electromigration of copper. Wetting and agglomeration of thin copper on several kinds of TiN films were analyzed by using AFM. Wetting/agglomeration differed among copper on different TiN layers. Also, the film texture of thicker copper films formed on these TiN films was analyzed by XRD. As interface wetting is better, the copper film has a higher texture, indicating that a better Cu/barrier interface and a better film texture occur simultaneously on a copper interconnect.