Ordering of block copolymer microstructures in corner geometries

TL;DR

This paper investigates how rounded corners in topographical templates can improve the continuity of lamellar block copolymer microstructures in nanopatterning applications, using simulation results.

Contribution

It introduces a simulation study showing that rounded corners can mitigate lamellae discontinuity caused by geometrical frustration in graphoepitaxy.

Findings

Rounded corners improve lamellae continuity in simulations

Geometrical frustration causes lamellae failure at corners

Rounded geometries could enhance nanopatterning techniques

Abstract

The ordering of block copolymers into lamellar microstructures is an attractive route for creating nanopatterns on scales too small to be constructed by current photolithography techniques. This utilises a technique known as graphoepitaxy where topography is used to define the alignment of the pattern for precise placement of pattern features. One problem with this approach is the failure of lamellae to maintain continuity around corners, due to geometrical frustration. We report simulation results using the extended Cahn-Hilliard equation which suggest that this problem could be solved by using rounded corners.