Figure 1
From: Metal hierarchical patterning by direct nanoimprint lithography
Schematic illustration of the MD-NIL.
(1) The spin coated Pd benzylthiolate film was imprinted using a Si mold (possessing ~2 μm grating structures) close to its melting temperature (~120°C) by applying a pressure of ~50 bar.(2) During imprinting, the molten precursor flowed into and filled the channels in the Si mold, following which the setup was cooled down. (3) After demolding, Pd benzylthiolate patterns on the substrate were heat treated at 250°C for 1 hr to obtain Pd patterns. At (2) stage, (a) hierarchical patterning can be done using a different Si mold with smaller feature sizes kept at right angles to the imprinted Pd benzylthiolate patterns. (b) Second MD-NIL leads to hierarchical Pd benzylthiolate patterns, which was heat treated (c). Transfer stacking - (d) using (2) as a mold and (3) as a substrate placed at right angles with respect to orientation of Pd lines, Pd benzylthiolate lines can be (e) transfer stacked by MD-NIL and (f) heat treated to get Pd crossbars. Polycarbonate (PC) transfer – (g) using (3) as mold and PC as substrate, imprinting by subjecting PC to glass transition (Tg), (h) following cooling, demolding led to PC carrying Pd lines, (i) which was heated on a hot plate to embed the Pd lines underneath PC surface.
