International Business Machines Corporation
Metallic interconnect structures with wrap around capping layers

Abstract:

Techniques are provided to fabricate metal interconnects using liner planarization-free process flows. A sacrificial layer is formed on a dielectric layer, and the sacrificial and dielectric layers are patterned to form an opening in the dielectric layer. A conformal liner layer is deposited, and a metal layer deposited to form a metal interconnect in the opening. An overburden portion of the metal layer is planarized to expose an overburden portion of the liner layer. A first wet etch is performed to selectively remove the overburden portion of the liner layer. A second wet etch process is performed to selectively remove the sacrificial layer, resulting in extended portions of the liner layer and the metal interconnect extending above a surface of the dielectric layer. A dielectric capping layer is formed to cover the sidewall and upper surfaces of the extended portions of the liner layer and the metal interconnect.