Chemically tailored block copolymers for highly reliable sub-10-nm patterns by directed self-assembly

• Published in: Nature communications Vol. 15; no. 1; pp. 5671 - 11
• Main Authors: Maekawa, Shinsuke, Seshimo, Takehiro, Dazai, Takahiro, Sato, Kazufumi, Hatakeyama-Sato, Kan, Nabae, Yuta, Hayakawa, Teruaki
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 06.07.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 140/131; 142/126; 147/135; 147/3; 639/301/357/341; 639/301/923/1028; 639/638/455/958; Annealing; Block copolymers; Copolymers; Humanities and Social Sciences; Interaction parameters; Lithography; Microscopy; Molecular weight; multidisciplinary; Polymerization; Polymers; Polymethyl methacrylate; Polymethylmethacrylate; Polystyrene; Polystyrene resins; Porous materials; Science; Science (multidisciplinary); Self-assembly; Thin films; Thiols; Vertical orientation
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-49839-0

While block copolymer (BCP) lithography is theoretically capable of printing features smaller than 10 nm, developing practical BCPs for this purpose remains challenging. Herein, we report the creation of a chemically tailored, highly reliable, and practically applicable block copolymer and sub-10-nm line patterns by directed self-assembly. Polystyrene- block -[poly(glycidyl methacrylate)- random -poly(methyl methacrylate)] (PS- b -(PGMA- r -PMMA) or PS- b -PGM), which is based on PS- b -PMMA with an appropriate amount of introduced PGMA (10–33 mol%) is quantitatively post-functionalized with thiols. The use of 2,2,2-trifluoroethanethiol leads to polymers (PS- b -PG F Ms) with Flory–Huggins interaction parameters ( χ ) that are 3.5–4.6-times higher than that of PS- b -PMMA and well-defined higher-order structures with domain spacings of less than 20 nm. This study leads to the smallest perpendicular lamellar domain size of 12.3 nm. Furthermore, thin-film lamellar domain alignment and vertical orientation are highly reliably and reproducibly obtained by directed self-assembly to yield line patterns that correspond to a 7.6 nm half-pitch size. Printing features with half pitch size of less than 10 nm by block copolymer lithography is challenging. Here, the authors employ directed self-assembly on tailored block co-polymers and achieved line pattern of 15.1 nm which corresponds to 7.6 nm half pitch size.