Nanopatterning using a simple bilayer lift-off process by transfer printing based on poly(dimethylsiloxane) templates

An efficient and versatile method for fabricating nanopatterns by a lift-off procedure is presented. The method involves an inked technique based on the poly(dimethylsiloxane) (PDMS) mould to fabricate a nanopatterned UV-curable resist as the top-layer and poly(methyl methacrylate) (PMMA) as the underlayer. The minimal residues are left on the PMMA because PDMS absorbs the organic molecules of UV-curable resist after the transferred step. High O₂ reactive ion etching selectivity of the top-layer to the underlayer is necessary to create the undercut pattern profile that is essential for the stable lift-off process. The UV-curable resist shows high etch resistance to O₂ plasma and PMMA serves as an underlying resin to create an undercut profile which is essential for the lift-off process. The etch rates of the PMMA film and UV-curable resist by O₂ plasma were examined as a function of bias voltage under various oxygen conditions during the etching process. To reveal the mechanism of etch resistance, the chemical composition of UV-curable resist was analysed before and after the O₂ plasma etching process by using X-ray photoelectron spectroscopy. As a result, the periodical patterns were fabricated using this bilayer lift-off process, which shows great potential in the fabrication of micro/nanodevices and in their applications.