Large area dense nanoscale patterning of arbitrary surfaces

We demonstrate a large-area fabrication of hexagonally ordered metal dot arrays with an area density of ${\text{∼10}}^{11}/{\mathrm{cm}}^{\mathrm{2}}.$ We produced 20 nm dots with a 40 nm period by combining block copolymer nanolithography and a trilayer resist technique. A self-assembled spherical-phase block copolymer top layer spontaneously generated the pattern, acting as a template. The pattern was first transferred to a silicon nitride middle layer by reactive ion etch, producing holes. The nitride layer was then used as a mask to further etch into a polyimide bottom layer. The metal dots were produced by an electron beam evaporation followed by a lift-off process. Our method provides a viable route for highly dense nanoscale patterning of different materials on arbitrary surfaces.