A method comprises forming a trench extending through an interlayer dielectric layer over a substrate and partially through the substrate, depositing a photoresist layer over the trench, wherein the photoresist layer partially fills the trench, patterning the photoresist layer to remove the photoresist layer in the trench and form a metal line trench over the interlayer dielectric layer, filling the trench and the metal line trench with a conductive material to form a via and a metal line, wherein an upper portion of the trench is free of the conductive material and depositing a dielectric material over the substrate, wherein the dielectric material is in the upper portion of the trench.