Aligned silicon nanofins via the directed self-assembly of PS-b-P4VP block copolymer and metal oxide enhanced pattern transferElectronic supplementary information (ESI) available. See DOI: 10.1039/c4nr07679f

• Main Authors: Cummins, Cian, Gangnaik, Anushka, Kelly, Roisin A, Borah, Dipu, O'Connell, John, Petkov, Nikolay, Georgiev, Yordan M, Holmes, Justin D, Morris, Michael A
• Format: Article
• Language: English
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c4nr07679f

'Directing' block copolymer (BCP) patterns is a possible option for future semiconductor device patterning, but pattern transfer of BCP masks is somewhat hindered by the inherently low etch contrast between blocks. Here, we demonstrate a 'fab' friendly methodology for forming well-registered and aligned silicon (Si) nanofins following pattern transfer of robust metal oxide nanowire masks through the directed self-assembly (DSA) of BCPs. A cylindrical forming poly(styrene)- block -poly(4-vinyl-pyridine) (PS- b -P4VP) BCP was employed producing 'fingerprint' line patterns over macroscopic areas following solvent vapor annealing treatment. The directed assembly of PS- b -P4VP line patterns was enabled by electron-beam lithographically defined hydrogen silsequioxane (HSQ) gratings. We developed metal oxide nanowire features using PS- b -P4VP structures which facilitated high quality pattern transfer to the underlying Si substrate. This work highlights the precision at which long range ordered ∼10 nm Si nanofin features with 32 nm pitch can be defined using a cylindrical BCP system for nanolithography application. The results show promise for future nanocircuitry fabrication to access sub-16 nm critical dimensions using cylindrical systems as surface interfaces are easier to tailor than lamellar systems. Additionally, the work helps to demonstrate the extension of these methods to a 'high χ ' BCP beyond the size limitations of the more well-studied PS- b -poly(methyl methylacrylate) (PS- b -PMMA) system. A strategy combining graphoepitaxy and a metal oxide enhanced PS- b -P4VP BCP is utilized for generating aligned Si nanofins with 10 nm feature sizes.