Large-area, highly ordered block copolymer nanopatterns via versatile molecular-assembly for nanodevice

Abstract

Block copolymers(BCPs) are self-assembling polymeric materials typically consisting of covalently linked, chemically distinctive macromolecular blocks. The microphase separation of immiscible respective blocks results in spontaneous assembly into nanoscale periodic arrays of spheres, cylinders, or lamellae whose characteristic dimensions are tunable in the range of 3-50 nm. BCPs lithography is emerging non-conventional nanolithographic process utilizing self-assembled morphologies of BCPs thin film where the periodic arrays of features are transferred onto desired substrates in nanometer scale. For the substantial applications in nanofabrication, the lateral and orientational control over BCPs microdomains are inevitable. Hence, various approaches including an external field, topographic confinement, chemically nanopatterned surfaces and solvent annealing, have been exploited to establish a macroscopically ordered nanoscale mor-phology. Here, I present large-area, highly ordered BCPs nanopatterns via versatile molecular-assembly for nanodevice. First, large-area, highly oriented lamellar BCPs nanopatterning directed by graphoepitaxially assembled cylinder nanopatterns. Asymmetric BCPs thin films were graphoepitaxially assembled within 1-μm-wide parallel photoresist trenches to generate surface-parallel nanocylinder arrays. After the graphoepi-taxial morphology was frozen by a radiative treatment, a thin film of symmetric BCPs was deposited over the nanocylinder array, where the lamellar period was consistent with the period of the underlying cylinder array. Subsequent thermal annealing generated highly aligned lamellar morphology over a large-area without any trace of an underlying photoresist pattern. Secondary, large-area, highly oriented lamellar BCPs nanopatterning directed by corrugated surface. The symmetric BCPs, having smaller molecular weight, thin films were graphoepitaxially assembled within 3-μm-wide parallel photoresist trenches and the PMMA blo...