Ultralarge scale integrated metallization and interconnects

Abstract

The use of copper interconnects enables higher speed, enhanced electromigration lifetime reliability, reduced power consumption, and ultimately reduced manufacturing cost for silicon integrated circuits. The formation of planarized inlaid copper interconnects requires sequential deposition of a continuous diffusion barrier layer followed by copper seed/fill deposition and chemical-mechanical polishing (CMP). In this article we present a vacuum-integrated cluster tool technology for deposition of a TaN barrier and copper seed/fill layers using metalorganic chemical vapor deposition (MOCVD). The MOCVD-based TaN layers deposited at substrate temperatures below 430 °C are highly conformal, have 800–1000 μΩ cm resistivity, have satisfactory adhesion to silicon dioxide, and provide superior diffusion barrier properties compared to Ta and TaN layers deposited by physical vapor deposition. The cluster MOCVD-Cu process is capable of depositing conformal and low-resistivity copper seed layers with satisfactory adhesion for subsequent copper filling by either electrochemical deposition or MOCVD. The cluster MOCVD technology has been used to fabricate inlaid copper metallization lines and plugs based on CMP damascene processing. The combination of MOCVD TaN and MOCVD copper is expected to provide an extendable multigenerational copper metallization solution for 0.18–0.10 μm technology nodes and beyond.