Interconnect structure with a planar interface between a selective conductive cap and a dielectric cap layer

Abstract

A selective conductive cap is deposited on exposed metal surfaces of a metal line by electroless plating selective to exposed underlying dielectric surfaces of a metal interconnect structure. A dielectric material layer is deposited on the selective conductive cap and the exposed underlying dielectric layer without a preclean. The dielectric material layer is planarized to form a horizontal planar surface that is coplanar with a topmost surface of the selective conductive cap. A preclean is performed and a dielectric cap layer is deposited on the selective conductive cap and the planarized surface of the dielectric material layer. Because the interface including a surface damaged by the preclean is vertically offset from the topmost surface of the metal line, electromigration of the metal in the metal line along the interface is reduced or eliminated.

Dependencies are inferred from the claim text.