Overview of interconnect technology for 7nm node and beyond - New materials and technologies to extend Cu and to enable alternative conductors (invited)

Although alternative conductors such as Co and Ru have intrinsic potentials for higher electromigration reliability than Cu and for competitive resistivity to Cu in fine dimensions, our measured resistivities of Co and Ru interconnects show twice of that of Cu interconnects still in dimension of 5 nm node. Key technologies to extend Cu interconnects to 7nm and beyond are the ALD/PVD modified TaN barrier and the Mn-assisted TaN barrier to achieve required (1) line/via-R, (2) electromigration/TDDB reliability and (3) via chain yield/manufacturability.