A method for manufacturing a semiconductor device includes providing a semiconductor structure having a semiconductor substrate, a dielectric layer on the semiconductor substrate, and a hardmask on a second portion of the dielectric layer while exposing a first portion of the dielectric layer; forming a copolymer on the semiconductor structure; performing an annealing treatment such that the copolymer forms a staggered configuration of a first monomer and a second monomer; removing the first monomer; performing a first etching process on the first portion using the second monomer as a mask to form a first trench extending to the semiconductor substrate; removing the second monomer and the first hardmask; and epitaxially growing a first semiconductor fin in the first trench.