A method of forming electrically conductive structures that includes forming a copper containing layer including a barrier forming element, and applying a first anneal to the copper containing layer. The first anneal increases grain size of the copper in the copper containing layer. The copper containing layer is etched to provide a plurality of copper containing lines. A dielectric fill is deposited in the space between adjacent copper containing lines. A second anneal is applied to the plurality of copper containing lines. During the second anneal the barrier forming element diffuse to an interface between sidewalls of the copper containing lines and the dielectric fill to form a barrier layer along the sidewalls of the copper containing lines.