Interconnect structure including airgaps and substractively etched metal lines

Abstract

Integrated circuits including at least two electrically conductive interconnect lines and methods of manufacturing generally include a surface of the integrated circuit. At least two electrically conductive interconnect lines are separated by a space of less than 90 nm and are formed on the surface. Each of the at least two interconnect lines includes a metal cap, a copper conductor having an average grain size greater than a line width of the interconnect. A liner layer is provided, wherein the liner layer and the metal cap encapsulate the copper conductor. A dielectric layer overlaying the at least two electrically conductive interconnect lines and extending along sidewalls thereof is provided, wherein the dielectric layer is configured to provide an airgap between the at least two interconnect lines at the spacing.