A method for forming CA power rails using a three mask decomposition process and the resulting device are provided. Embodiments include forming a horizontal diffusion CA power rail in an active layer of a semiconductor substrate using a first color mask; forming a plurality of vertical CAs in the active layer using second and third color masks, the vertical CAs connecting the CA power rail to at least one diffusion region on the semiconductor substrate, spaced from the CA power rail, wherein each pair of CAs formed by one of the second and third color masks are separated by at least two pitches.