Methods of forming a semiconductor structure includes etching a via opening through an interlevel dielectric to a metal conductor. A contiguous metal liner is deposited onto exposed surfaces of the substrate. The substrate is exposed to a gaseous ion plasma to remove portions of the metal liner that are horizontally oriented and to reduce a height of the metal liner from portions thereof that are vertically oriented. Subsequently, a trench opening is formed in the interlevel dielectric, wherein the trench opening is connected with the via opening, wherein at least a portion of the metal liner remains on sidewall surfaces within the via opening during the forming of the trench opening. A diffusion barrier liner is deposited within the trench opening and the via opening. A conductive material is formed within remaining portions of the trench opening and the via opening to define the interconnect structure.