title: Perpendicular Orientation Control without Interfacial Treatment of RAFT-Synthesized High-χ Block Copolymer Thin Films with Sub-10 nm Features Prepared via Thermal Annealing.
abstract: In this study, a series of perpendicular lamellae-forming poly(polyhedral oligomeric silsesquioxane methacrylate-block-2,2,2-trifluoroethyl methacrylate)s (PMAPOSS-b-PTFEMAs) was developed based on the bottom-up concept of creating a simple yet effective material by tailoring the chemical properties and molecular composition of the material. The use of silicon (Si)-containing hybrid high-χ block copolymers (BCPs) provides easy access to sub-10 nm feature sizes. However, as the surface free energies (SFEs) of Si-containing polymers are typically vastly lower than organic polymers, this tends to result in the selective segregation of the inorganic block onto the air interface and increased difficulty in controlling the BCP orientation in thin films. Therefore, by balancing the SFEs between the organic and inorganic blocks through the use of poly(2,2,2-trifluoroethyl methacrylate) (PTFEMA) on the organic block, a polymer with an SFE similar to Si-containing polymers, orientation control of the BCP domains in thin films becomes much simpler. Herein, perpendicularly oriented BCP thin films with a χeffvalue of 0.45 were fabricated using simple spin-coating and thermal annealing processes under ambient conditions. The thin films displayed a minimum domain size of L0= 11 nm, as observed via atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Furthermore, directed self-assembly (DSA) of the BCP on a topographically prepatterned substrate using the grapho-epitaxy method was used to successfully obtain perpendicularly oriented lamellae with a half pitch size of ca. 8 nm.
authors.affiliation: Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology , 2-12-1-S8-36 Ookayama, Meguro-ku, Tokyo 152-8552, Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Nakatani
authors.affiliation: Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology , 2-12-1-S8-36 Ookayama, Meguro-ku, Tokyo 152-8552, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takano
authors.affiliation: Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology , 2-12-1-S8-36 Ookayama, Meguro-ku, Tokyo 152-8552, Japan.
authors.forename: Alvin
authors.initials: A
authors.lastname: Chandra
authors.affiliation: Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology , 2-12-1-S8-36 Ookayama, Meguro-ku, Tokyo 152-8552, Japan.
authors.forename: Yasunari
authors.initials: Y
authors.lastname: Yoshimura
authors.affiliation: Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology , 2-12-1-S8-36 Ookayama, Meguro-ku, Tokyo 152-8552, Japan.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology , 2-12-1-S8-36 Ookayama, Meguro-ku, Tokyo 152-8552, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology , 2-12-1-S8-36 Ookayama, Meguro-ku, Tokyo 152-8552, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology , 2-12-1-S8-36 Ookayama, Meguro-ku, Tokyo 152-8552, Japan.
authors.forename: Rina
authors.initials: R
authors.lastname: Maeda
authors.affiliation: DSA Research Department, EUVL Infrastructure Development Center, Inc. , 16-1 Onogawa, Tsukuba-shi, Ibaraki 305-8569, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Kihara
authors.affiliation: DSA Research Department, EUVL Infrastructure Development Center, Inc. , 16-1 Onogawa, Tsukuba-shi, Ibaraki 305-8569, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Minegishi
authors.affiliation: DSA Research Department, EUVL Infrastructure Development Center, Inc. , 16-1 Onogawa, Tsukuba-shi, Ibaraki 305-8569, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Miyagi
authors.affiliation: DSA Research Department, EUVL Infrastructure Development Center, Inc. , 16-1 Onogawa, Tsukuba-shi, Ibaraki 305-8569, Japan.
authors.forename: Yuusuke
authors.initials: Y
authors.lastname: Kasahara
authors.affiliation: DSA Research Department, EUVL Infrastructure Development Center, Inc. , 16-1 Onogawa, Tsukuba-shi, Ibaraki 305-8569, Japan.
authors.forename: Hironobu
authors.initials: H
authors.lastname: Sato
authors.affiliation: DSA Research Department, EUVL Infrastructure Development Center, Inc. , 16-1 Onogawa, Tsukuba-shi, Ibaraki 305-8569, Japan.
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Seino
authors.affiliation: DSA Research Department, EUVL Infrastructure Development Center, Inc. , 16-1 Onogawa, Tsukuba-shi, Ibaraki 305-8569, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Azuma
authors.affiliation: Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Yokoyama
authors.affiliation: Department of Materials Science and Engineering, Cornell University , Ithaca, New York 14853-1501, United States.
authors.forename: Christopher K
authors.identifier: http://orcid.org/0000-0002-3805-3314
authors.initials: CK
authors.lastname: Ober
authors.affiliation: Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology , 2-12-1-S8-36 Ookayama, Meguro-ku, Tokyo 152-8552, Japan.
authors.forename: Teruaki
authors.identifier: http://orcid.org/0000-0002-1704-5841
authors.initials: T
authors.lastname: Hayakawa
keywords: block copolymer lithography; directed self-assembly; hybrid block copolymer; interfacial control; nonpreferential interface; orientation control; perpendicular lamellae; sub-10 nm