A method for forming contact vias includes providing a substrate comprising a plurality of contact structures embedded in a first dielectric layer, the contacts abutting an upper surface of the first dielectric layer. The method also includes providing a second dielectric layer on the upper surface of the first dielectric layer, and providing contact vias in the second dielectric layer by patterning the second dielectric layer at least at positions corresponding to the contact structures, wherein patterning the second dielectric layer comprises using a DSA patterning technique.