Three-Dimensional Nanofabrication with Sub-20 nm Resolution and Eight-Inch Wafer Scalability via Thermally Assisted Nanotransfer Printing

Nanotransfer printing (nTP) is one of the promising nanofabrication methods due to its process simplicity, cost-effectiveness, and scalability for two-/three-dimensional nanostructures. However, various nTP techniques still have critical challenges for realizing sub-50 nm high-resolution pattern formation at wafer-scale. Here, we introduce a simple and practical thermally assisted nanotransfer printing (T-nTP) process that can effectively produce well-ordered sub-20 nm nanostructures over an 8-inch wafer by the use of a heat-rolling-press system that can provide uniform heat and pressure. The T-nTP process enables reliable pattern formation of metallic (Pt, Pd, Ag) and semiconducting (NiO, WO₃, Ge_xSb_yTe_z) materials with functionalities on diverse substrates including rigid Si, flexible polyethylene terephthalate (PET), and slippery glass. Furthermore, we show the formation of ultrafine (≤ 20 nm) 3D hierarchical nanostructures via the combined method of T-nTP and directed self-assembly (DSA) of block copolymers (BCPs). Moreover, we also demonstrate how to obtain a high-density NiO<i>_x</i>/Pt memristive crossbar nanoscale pattern with a width of 14 nm, showing excellent unipolar resistive switching behavior. We expect that the proposed novel T-nTP method will be applicable to high-throughput nanofabrication combined with other patterning techniques.