ELECTROMIGRATION RESISTANT INTERCONNECT STRUCTURE

摘要

A line trench is formed in a dielectric layer that may contain an interlayer dielectric material. A metal liner is formed on the sidewalls and the bottom surface of the line trench. A conductive metal is deposited within a remaining portion of the line trench at least up to a top surface of the dielectric layer and planarized to form a metal line in the line trench. The metal line is recessed by a recess etch below the top surface of the dielectric layer. A dielectric line cap or a metallic line cap is formed by deposition of a dielectric cap layer or a metallic cap layer, followed by planarization of the dielectric or metallic cap layer. The dielectric line cap or the metallic line cap applies a highly compressive stress on the underlying metal line, which increases electromigration resistance of the metal line.