Berlin 2018 – scientific programme
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O: Fachverband Oberflächenphysik
O 105: Nanostructures at surfaces: 1D and 2D structures and networks III
O 105.3: Talk
Thursday, March 15, 2018, 17:45–18:00, MA 141
Hierarchical nanostructures by combining block copolymer and nanosphere lithography — •Daniel Kool1,2, Katharina Brassat1,2, and Jörg K. N. Lindner1,2 — 1Paderborn University, Dept. of Physics, Paderborn, Germany — 2Center for Optoelectronics and Photonics Paderborn (CeOPP), Paderborn, Germany
Block copolymer (BCP) lithography is a well-established technique for economical large-area surface structuring exploiting the microphase separation of a copolymer, here poly(styrene-b-methylmethacrylat) (PS-b-PMMA) BCP into self-assembled nanopatterns. Using a block length ratio of 70:30 we achieve perpendicular, 17 nm diameter PMMA cylinders hexagonally arranged in a PS-Matrix. After removing selectively the PMMA cylinders a pore density up to 9.5 · 1010 cm−2 is achieved. SEM images are evaluated by a self-written Delaunay-triangulation based software. In order to guide the self-assembly process of nanopores, we prepattern the substrate surface using nanosphere lithography (NSL). To this end convective self-assembly of polystyrene nanospheres in a colloidal suspension in used to generate a hexagonally close packed array of spheres. Spheres are shrunk in an oxygen plasma and used as a shadow mask in a metal thin film deposition. After removal of the sphere mask a hexagonal array of open cylinders (antidots) in the metal film is achieved. We demonstrate that using these antidots as template for the BCP lithography allows for the site-selective creation of both nanopore arrays and concentric PS rings inside antidots.