A method of forming a semiconductor device fabrication is described that includes forming a material layer over a substrate, forming a first trench in the material layer, forming a first dielectric capping layer along sidewalls of the first trench, forming a second trench in the material layer while the capping layer disposed along sidewalls of the first trench, forming a second dielectric capping layer along sidewalls of the second trench and along the sidewalls of the first trench and forming a conductive feature within the second trench and the first trench.