Aligned silicon nanofins via the directed self-assembly of PS-b-P4VP block copolymer and metal oxide enhanced pattern transfer

'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 similar to 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 chi' BCP beyond the size limitations of the more well-studied PS-b-poly(methyl methylacrylate) (PS-b-PMMA) system.