Design of high-[chi] block copolymers for lithography

This report describes the design and synthesis of a series of lamella-forming, silicon-containing block copolymers (Si-BCPs) and evaluation of these materials as potential candidates for lithographic applications. The interaction parameter χ of each Si-BCP is measured by both the mean-field theory predicted order-disorder transition and by analysis of X-ray scattering profiles. The introduction of more-polar methoxy and less-polar methylsilyl moieties increases χ to about 2-3 times that of the reference material, poly(styrene-block-4-trimethylsilylstyrene). The incremental increases appear to be essentially additive in this family of block copolymers, suggesting that improvements in χ can be predicted from appropriate monomer choice. Perpendicularly oriented thin-films of the ordered Si-BCPs generated by thermally annealing between two "neutral" polymeric surfaces and developed by etching on commercial RIE equipment show excellent image fidelity. These images demonstrate the excellent etch contrast of the Si-BCPs and document improvements in pattern fidelity that are realized with more strongly segregated BCPs. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 344-352