Directed Self-Assembly of Block Copolymer Thin Films Using Minimal Topographic Patterns

Jaewon Choi, June Huh, Kenneth R. Carter, Thomas P. Russell

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

We demonstrate that a minimal topographic pattern with a confinement depth (D) much less than the domain spacing of block copolymers (L0) can be used to achieve highly ordered hexagonal arrays or unidirectionally aligned line patterns over large areas. Cylinder-forming poly(styrene-b-ethylene oxide) (PS-b-PEO) thin films were prepared on a series of minimal single trench patterns with different widths (W) and D. Upon thermal annealing, hexagonal arrays of cylindrical microdomains propagated away from the edges of a single trench, providing insight into the minimum pitch (P) of the trench necessary to fully order hexagonal arrays. The confinement trench D of 0.30L0, the W in the range of 1.26L0 to 2.16L0, and the P as long as 18.84L0 were found to be effective for the generation of laterally ordered hexagonal arrays with the density amplification up by a factor of 17, within the minimally patterned trench surfaces of 100 μm by 100 μm. Furthermore, we produced line patterns of cylindrical microdomains by using solvent vapor annealing on the minimally patterned trench surfaces. However, highly aligned line patterns could be achieved only on the patterned surface with P = 5.75L0, W = 1.26L0, and D = 0.30L0 because the influence of the minimally patterned trench surface on the lateral ordering decreased as the P and W increase at the fixed D, resulting in poor ordering. These findings suggest that the minimal topographic pattern is more effective in guiding hexagonal arrays than in guiding line patterns.

Original languageEnglish
Pages (from-to)7915-7925
Number of pages11
JournalACS Nano
Volume10
Issue number8
DOIs
Publication statusPublished - 2016 Aug 23

Keywords

  • block copolymers
  • cylindrical microdomains
  • directed self-assembly
  • lateral ordering
  • minimal topographic patterns

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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