Lattice Deformation and Domain Distortion in the Self-Assembly of Block Copolymer Thin Films on Chemical Patterns

Authors

  • Ji Xu,

    1. Department of Polymer Science and Engineering, University of Massachusetts, Amherst, MA 01003, USA
    Current affiliation:
    1. GLOBALFOUNDRIES, 257 Fuller Rd., NFS Suite 380, Albany, NY 12230, USA
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  • Thomas P. Russell,

    Corresponding author
    1. Department of Polymer Science and Engineering, University of Massachusetts, Amherst, MA 01003, USA
    • Department of Polymer Science and Engineering, University of Massachusetts, Amherst, MA 01003, USA
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  • Antonio Checco

    Corresponding author
    1. Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
    • Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
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Abstract

The self-assembly of cylinder-forming block copolymer (BCP) microdomains confined within chemical stripe patterns of widths incommensurate with the natural period of the copolymers, L0, is studied. It is shown that this incommensurability causes changes in both the shapes of the microdomains and their spatial period. Specifically, a transition from n to n + 1 rows of microdomains is observed when the stripe width is about n ± 1/2 L0. When the stripe's width is comparable to L0, ellipticity of microdomains can be induced with an aspect ratio up to 2.2. Free energy models are applied to describe the energetic origin of such behavior. Although our observations qualitatively resemble results in sphere-forming BCPs confined in topographical trenches, the quantitative difference is noteworthy and technologically important for the design of nanostructures with programmable shapes.

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