Multiscale manufacturing of metallic nanopore arrays

A.O. Altun, T. Bond, H.G. Park
ETH Zurich,
Switzerland

Keywords: block copolymer self-assembly, multi-scale nanomanufacturing

Summary:

Realizing uniform and wafer-scale coverage of ultradense arrays of nanopores on metal thin films is still a big challenge with the current nanomanufacturing methods. We established a low-cost, high-throughput, lift-off-free nanolithographic method for creating hexagonal arrays of sub-30-nm-sized pores on a metal film, achieving uniform coverage over an entire wafer of 10 cm in diameter. Spherical nanodomains of poly(methyl methacrylate) (PMMA) are demonstrated to be well-controlled and self-aligned within a polystyrene (PS) matrix layer on a metal thin film without any intermediary coating. After removal of PMMA, the porous PS thin film acts as an etch mask for defining nanoscale pores in the metal underlayer by Ar ion beam milling, resulting in wafer-scale patterning with great fidelity. Conditions for such uniformity control of the nanopore arrays critically depend on the initial roughness of the metal layer, from which the best parametric conditions are deduced. Macroscale coverage of nanoporous metal arrays poses great potential in a wide variety of fields in optics, electronics, energy and biotechnology.