In-Situ Grown Graphene Enabled Copper Interconnects With Improved Electromigration Reliability

Reliability of 80-, 100-, and 120-nm wide copper interconnects is improved using in situ grown graphene as a capping material. The graphene-capped Cu wires exhibit 2.4–3.5 $\times $ longer electromigration (EM) lifetime than thermally annealed Cu. In addition, the Cu resistivity is reduced by about 12%–30% and the breakdown current density is increased by 5%–7%. The graphene cap improves the Cu EM lifetime by mitigating Cu void formation at the interface. However, low-temperature grown graphene oxidizes readily and thus provides limited oxidation protection for the Cu wires.