Highly aligned block copolymer thin films by synergistic coupling of static graphoepitaxy and dynamic thermal annealing fields

Abstract

Directed self-assembly of cylinder forming block copolymer (c-BCP) thin films via a dynamic thermal field on multidimensional symmetric graphoepitaxy channels is reported. A synergy of dynamic thermal and static boundary fields induces highly aligned c-BCP cylinders inside the channels with a power law dependence of orientational order parameter f, on trench width, f ∼ d -0.3, analogous to dual-field alignment of semiconducting metals and liquid crystals on graphoepitaxy surfaces, f′ ∼ d-1. Static thermal annealing of identical films in a vacuum oven for several days fails to produce comparable results. Furthermore, we demonstrate global c-BCP cylinder alignment over mesas and trenches by tuning the synergy between the dynamic thermal field and asymmetry of the graphoepitaxy static field. © 2013 American Chemical Society.