Semiconductor devices and methods for forming the semiconductor devices include first line trenches formed in a dielectric layer on a substrate. Sacrificial spacers are formed on sidewalls of the dielectric layer in the first line trenches. Second line trenches are formed in the dielectric layer, the first line trenches and the second line trenches including alternating rows of trenches separated by the sacrificial spacers. The first line trenches and the second line trenches are filled with conductive material to form conductive lines. The sacrificial spacers are replaced with an isolation material.