Silver Electromigration Resistance

Abstract

Electromigration has been identified as a primary failure mode of interconnect lines used in semiconductor-integrated circuits. It is a high-current density induced mass transport phenomenon manifesting itself as voids, hillocks, or open circuits, due to a momentum exchange between conduction electrons and host metal atoms. The electromigration failure of Al(Cu) interconnects has been extensively investigated because of the dominant use of Al(Cu) as conductors in microelectronics devices for decades. Recently, the electromigration study of Cu has been conducted considerably as well, since the trend to replace Al(Cu) with Cu is becoming apparent for ultra large scale integration (ULSI) applications. Ag, as the most conductive metal, has also drawn attention as an interconnect material for some potential applications in ULSI [1],[2]. Ag has some advantage over Cu in terms of the conductivity.