Selective sidewall wetting of polymer blocks in hydrogen silsesquioxane directed self-assembly of PS-b-PDMS

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Hobbs, Richard G.
Farrell, Richard A.
Bolger, Ciara T.
Kelly, Róisín A.
Morris, Michael A.
Petkov, Nikolay
Holmes, Justin D.
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American Chemical Society (ACS)
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We show the importance of sidewall chemistry for the graphoepitaxial alignment of PS-b-PDMS using prepatterns fabricated by electron beam lithography of hydrogen silsesquioxane (HSQ) and by deep ultraviolet (DUV) lithography on SiO2 thin films. Density multiplication of polystyrene-block-polydimethylsiloxane (PS-b-PDMS) within both prepatterns was achieved by using a room temperature dynamic solvent annealing environment. Selective tuning of PS and PDMS wetting on the HSQ template sidewalls was also achieved through careful functionalization of the template and substrate surface using either brush or a self-assembled trimethylsilyl monolayer. PDMS selectively wets HSQ sidewalls treated with a brush layer of PDMS, whiereas PS is found to selectively wet HSQ sidewalls treated with hexamethyldisilazane (HMDS) to produce a trimethylsilyl-terminated surface. The etch resistance of the aligned polymer was also evaluated to understand the implications of using block copolymer patterns which have high etch resistance, self-forming (PDMS) wetting layers at both interfaces. The results outlined in this work may have direct applications in nanolithography for continued device scaling toward the end-of-roadmap era.
Block copolymer , Electron beam lithography , Hydrogen silsesquioxane , Nanolithography , Surface functionalization , Templated self-assembly
Hobbs, R. G., Farrell, R. A., Bolger, C. T., Kelly, R. A., Morris, M. A., Petkov, N. and Holmes, J. D. (2012) 'Selective Sidewall Wetting of Polymer Blocks in Hydrogen Silsesquioxane Directed Self-Assembly of PS-b-PDMS', ACS Applied Materials & Interfaces, 4(9), pp. 4637-4642. doi: 10.1021/am301012p
© 2012 American Chemical Society. This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials & Interfaces, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see