The authors have demonstrated a method to form 20nm contact features of uniform size over a large area by integrating a self-assembling diblock copolymer with optical lithography. The diblock copolymer contacts are formed in topographical placers which are patterned with using optical lithography. A diblock copolymer pattern can only be formed in a placer and not in the narrower trenches that connect to the placer. This concept can be applied to form local interconnects using a single mask dual damascene process, where vias are self-aligned to the line. Some design rule restrictions must be applied to certain structures to enable patterning with diblock copolymer. They also observed that diblock copolymer contact formation was strongly influenced by the shape of the placer and the size of the cylindrical contact hole could be varied by the molecular weight of the block copolymer.