Universal perpendicular orientation of block copolymer microdomains using a filtered plasma

Abstract

Sub-10 nm patterns prepared by directed self-assembly (DSA) of block copolymer (BCP) thin films offer a breakthrough method to overcome the limitations of photolithography. Perpendicular orientation of the BCP nanostructures is essential for lithographic applications, but dissimilar surface/interfacial energies of two blocks generally favour parallel orientations, so that the perpendicular orientation could only be obtained under very limited conditions. Here, we introduce a generalized method for creating perpendicular orientations by filtered plasma treatment of the BCP films. By cross-linking the surface of disordered BCP films using only physical collisions of neutral species without ion bombardment or UV irradiation, neutral layers consistent with the BCP volume fraction are produced that promote the perpendicular orientations. This method works with BCPs of various types, volume fractions, and molecular weights individually at the top and bottom interfaces, so it was applied to orientation-controlled 3D multilayer structures and DSA processes for sub-10 nm line-spacing patterns.

WITHDRAWN: Bending Behaviors and Directed Self-assembly of Rod-Coil Block Copolymers

“…29,30 The presence of silicon imparts a high etch selectivity between the two blocks, and is converted to silicon oxide on etching in oxygen, simplifying pattern transfer and making PDMS-containing BCPs attractive for nanolithography applications. 15,31,32 We have produced well-ordered in-plane cylindrical silica patterns from PDMS-b-PMPCS thin lms by thermal annealing, 29 and a variety of core-shell patterns from a PDMS-b-PS-b-PMPCS (or DSM) triblock terpolymer by solvent vapor annealing, 26 and also have generated well-ordered lamellae with out-of-plane orientation through a two-step annealing method. 30 In this article, we demonstrate grating patterns with spontaneous sharp bends and Y-junctions as well as a tunable periodicity and line/space ratio from a series of rod-coil DM and DSM BCPs.…”

Non‐Native Block Copolymer Thin Film Nanostructures Derived from Iterative Self‐Assembly Processes

“…As a result, the BCP community faces up to a challenge in translating these novel complex structures into potent applicative advances with smart functionalities, as only a scarce number of the multilayered structures described herein has been transitioned to device manufacturing. For instance, 3D nanostructures formed by directed self‐assembly of BCP multilayers could be valuable in cutting‐edge technologies such as optical metamaterials or metasurfaces, graphene nanoribbon or fin field effect transistors, filtration membranes with improved permeability‐selectivity tradeoff, cross‐point memories, or optoelectronic devices . Additionally, the conversion of the BCP scaffolds into functional inorganic materials broadens the scope of applications by adding specific optical, electronic, or magnetic properties to the 3D nanostructures .…”

“…Such cross‐linked layer can further act as a neutral top‐coat for the underlying BCP layer or as neutral underlayer for a BCP layer deposited on top of it. Reproduced under the terms of the Creative Commons Attribution 4.0 International License . Copyright 2019, the Authors.…”

“…Recently, Oh et al have demonstrated how a cross‐linked layer can also be applied to the fabrication of orientation‐controlled 3D multilayer structures . Through filtered plasma treatment of BCP thin films, a thin cross‐linked layer was formed by the physical collisions of neutral species and retains the original chemical BCP composition, thus acting as a neutral top‐coat for the underlying BCP layer or as neutral underlayer for a BCP layer deposited on top of it.…”

High‐Fidelity, Sub‐5 nm Patterns from High‐χ Block Copolymer Films with Vapor‐Deposited Ultrathin, Cross‐Linked Surface‐Modification Layers

“…To further confirm the nature of confinement in the Ran/Ran, DVB/Ran, and DVB/DVB films, the film thickness dependent orientation was analyzed using grazing‐incidence small angle X‐ray scattering (GISAXS) at a beam incident angle α i = 0.16° (i.e., full penetration of film, critical angle for PS is 0.09–0.15° and that for polymer films are typically <0.15° for an incident X‐ray of 11.025 keV). Figure shows the 2D GISAXS image for unetched Ran/Ran, DVB/Ran, and DVB/DVB films with PS ‐b‐ PMAA film thicknesses, t = 1.50 L 0 , 1.71 L 0 , 2.05 L 0 , and ≈5 L 0 .…”