title: Deep-nanoscale pattern engineering by immersion-induced self-assembly.
abstract: The directed self-assembly (DSA) of block copolymers (BCPs) is expected to complement conventional optical lithography due to its excellent pattern resolution and cost-effectiveness. Recent studies have shown that BCPs with a large Flory-Huggins interaction parameter (χ) are critical for a reduction of the thermodynamic defect density as well as an increase in pattern density. However, due to their slower self-assembly kinetics, high-χ BCPs typically necessitate solvent vapor annealing, which requires complex facilities and procedures compared to simple thermal annealing. Here, we introduce an immersion-triggered directed self-assembly (iDSA) process and demonstrate the combined advantages of excellent simplicity, productivity, large-area capability, and tunability. We show that the vapor-free, simple immersion of high-χ BCPs in a composition-optimized mixture of nonswelling and swelling solvents can induce the ultrafast (≤ 5 min) formation of nanoscale patterns with a pattern size ranging from 8-18 nm. Moreover, iDSA enables the reversible formation of seven different nanostructures from one sphere-forming BCP, demonstrating the outstanding controllability of this self-assembly route.
authors.affiliation: Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST) , 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Woon Ik
authors.initials: WI
authors.lastname: Park
authors.forename: Jong Min
authors.initials: JM
authors.lastname: Kim
authors.forename: Jae Won
authors.initials: JW
authors.lastname: Jeong
authors.forename: Yeon Sik
authors.initials: YS
authors.lastname: Jung
keywords: immersion; lithography; polymer; self-assembly; sub-15 nm