High χ-low N fluorine-based block copolymers for sub-10 nm lithography

We will discuss the attractive properties of high χ-low N fluoro based BCPs and illustrate their utility for next-generation nanolithography. The synthesis, physical characterization and thin film self-assembly of a series of lamellar and cylindrical fluorine based BCPs will be described. Total BCP molecular weights ranging from 39 kg mol^-1 to 7 kg mol^-1 were synthesized using reversible-addition-fragmentation chain-transfer (RAFT) polymerization. Tailoring the fluorine containing blocks here resulted in a similar surface free energy to the well-studied polymethylmethacrylate (~ 41 mN/m) based BCPs thereby making orientational control in thin films more attractive. Solvo-thermal vapor annealing and thermal annealing of films were evaluated with a view to standardised industry methods. Period sizes ranged from 48 nm down to 14 nm with observed feature sizes as small as 7 nm. We also demonstrate the integration feasibility of our new fluorine based BCPs using sequential infiltration synthesis to form alumina nanowire hardmasks. The favorable BCP characteristics detailed here provide a versatile material option to the current library of available BCPs for nanolithography.