A device includes a first dielectric material and a plurality of conductive lines disposed in the first dielectric material. Each of the plurality of conductive lines includes a conductive fill material and a liner layer disposed between at least a bottom surface of the conductive fill material and the first dielectric material. The first dielectric material defines at least one air gap between two of the plurality of conductive lines. The at least one air gap has a first depth greater than a second depth of the plurality of conductive lines.
