High-x Block Copolymers Based on Vinyl Pyridine for Microelectronics

Microelectronic device features continue to decrease in size, pushing the limits of photolithography and therefore requiring increasingly expensive multi-patterning techniques to achieve the current 14 nm node and to push beyond that. An alternative bottom-up design uses self-assembly of phase separated block copolymers to increase the frequency of a pre-pattern created by traditional photolithography. This work focuses on a block copolymer of poly(4-trimethylsilyl styrene)-b-poly(2-vinylpyridine) (PTMSS-P2VP) that was produced by anionic polymerization. This polymer has a 50:50 volume fraction for each block and a molecular weight of 7.9kDa by MALDI. The high chemical incompatibility between the hydrophobic PTMSS and the hydrophilic P2VP enables phase separation even at small molecular weights, allowing for 10 nm features as measured by SAXS and confirmed by AFM. Polarity-switching top coats made of maleic anhydride/di-t-butyl styrene/t-butyl styrene and cross–linkable bottom coats made of methyl methacrylate/t-butyl styrene were optimized to create perpendicular lamella in thin films, demonstrating the usefulness of this polymer for patterning application in microelectronics.