A process for forming patterned copper lines, a pattern of copper lines, and an electronic device having patterned copper lines and at least one CMOS circuit. The process includes assembling an etch stack, wherein the etch stack includes a resist and a copper substrate. The process also includes lithographically patterning the resist to produce a template, and forming a patterned block copolymer mask layer by directed self-assembly. Additionally, the process includes etching portions of the block copolymer mask layer to produce a patterned block copolymer mask layer, and transferring a pattern formed by the template and the patterned block copolymer mask layer to the copper substrate to form the patterned copper lines.