Improving the Electromigration Life of Advanced Interconnects through Graphene Capping

Since the discovery of graphene, 2D materials are establishing a rapidly growing and promising field, with great potential for diverse applications given their excellent conductivity and high transparency. In particular, graphene can isolate external chemical reactions when applied to back-end-of-line (BEOL) interconnect metals, thereby preventing the oxidation of the interconnect metals. In addition, it can improve the conductivity and breakdown current density of interconnects. However, the thermal budget remains an important problem in BEOL interconnects. We demonstrate an advanced graphene deposition method using an in-house plasma plasma-enhanced chemical vapor deposition system, which offers low thermal budget and high stability. We also optimize carbon precursors to improve the quality of graphene on Ru and Co thin films. We show the improvement of electrical conductivity, electromigration lifetime, and maximum breakdown current density after capping Ru and Co interconnects with graphene. The electromigration lifetimes of the Ru and Co interconnects increase by 4 and 4.5 times, respectively, and their maximum breakdown current density increases by 17.6 and 10.6%, respectively. The results show that capping with graphene has a high potential in BEOL applications.