Device Fabrication by Easy Soft Imprint Nano-Lithography

A new robust and exceptionally simple procedure for soft nano-imprint lithography (Soft-NIL) is described, which provides easy access to nanoscale patterns of a host of active materials on a Si/SiO x surface. Partial curing of a thiol-ene based UV cross-linkable resin (<1 μm) for 30−40 s prior to imprinting resulted in sufficient buildup of resin molecular weight to prevent its absorption into polydimethylsiloxane molds yet maintain a low enough viscosity to allow for rapid molding of nanoscale features during the subsequent imprint-and-cure stage of the process. Imprinted features were easily transferred to the underlying substrate by traditional reactive ion etching and lift-off processes. Easy soft imprint nano-lithography (ESINL) permitted the use of untreated PDMS molds for replicating patterns in gold, nickel, and complex aluminum capped silicon structures. ESINL was used to fabricate organic field effect transistors (poly(3,3′′′-didodecylquaterthiophene, W / L = 204, μ sat = 6.0 × 10 −3 cm 2 /(V·s)), demonstrating the first use of a soft imprint lithographic process to make such devices.