title: Reduction of Line Edge Roughness of Polystyrene-block-Poly(methyl methacrylate) Copolymer Nanopatterns By Introducing Hydrogen Bonding at the Junction Point of Two Block Chains.
abstract: To apply well-defined block copolymer nanopatterns to next-generation lithography or high-density storage devices, small line edge roughness (LER) of nanopatterns should be realized. Although polystyrene-block-poly(methyl methacrylate) copolymer (PS-b-PMMA) has been widely used to fabricate nanopatterns because of easy perpendicular orientation of the block copolymer nanodomains and effective removal of PMMA block by dry etching, the fabricated nanopatterns show poorer line edge roughness (LER) due to relatively small Flory-Huggins interaction parameter (χ) between PS and PMMA chains. Here, we synthesized PS-b-PMMA with urea (U) and N-(4-aminomethyl-benzyl)-4-hydroxymethyl-benzamide (BA) moieties at junction of PS and PMMA chains (PS-U-BA-PMMA) to improve the LER. The U-BA moieties serves as favorable interaction (hydrogen bonding) sites. The LER of PS line patterns obtained from PS-U-BA-PMMA was reduced ∼25% compared with that obtained from neat PS-b-PMMA without BA and U moieties. This is attributed to narrower interfacial width induced by hydrogen bonding between two blocks, which is confirmed by small-angle X-ray scattering. This result implies that the introduction of hydrogen bonding into block copolymer interfaces offers an opportunity to fabricate well-defined nanopatterns with improved LER by block copolymer self-assembly, which could be a promising alternative to next-generation extreme ultraviolet lithography.
authors.affiliation: National Creative Research Initiative Center for Smart Block Copolymers, Department of Chemical Engineering, Pohang University of Science and Technology , Pohang, Kyungbuk 37673, Republic of Korea.
authors.forename: Kyu Seong
authors.initials: KS
authors.lastname: Lee
authors.affiliation: National Creative Research Initiative Center for Smart Block Copolymers, Department of Chemical Engineering, Pohang University of Science and Technology , Pohang, Kyungbuk 37673, Republic of Korea.
authors.forename: Jaeyong
authors.initials: J
authors.lastname: Lee
authors.affiliation: National Creative Research Initiative Center for Smart Block Copolymers, Department of Chemical Engineering, Pohang University of Science and Technology , Pohang, Kyungbuk 37673, Republic of Korea.
authors.forename: Jongheon
authors.initials: J
authors.lastname: Kwak
authors.affiliation: Department of Chemical Engineering, University of Seoul , Seoul 02504, Republic of Korea.
authors.forename: Hong Chul
authors.initials: HC
authors.lastname: Moon
authors.affiliation: National Creative Research Initiative Center for Smart Block Copolymers, Department of Chemical Engineering, Pohang University of Science and Technology , Pohang, Kyungbuk 37673, Republic of Korea.
authors.forename: Jin Kon
authors.identifier: http://orcid.org/0000-0002-3872-2004
authors.initials: JK
authors.lastname: Kim
keywords: PS-b-PMMA; block copolymer; hydrogen bonding; interfacial width; line edge roughness; polystyrene-block-poly(methyl methacrylate) copolymer