Directed self-assembly of block copolymers

Block copolymers in the strong segregation regime self-assemble to form regular periodic nanopatterns that are applicable as templates for nanofabrication or nanoprocessing such as etching masks for nanolithography. However, self-assembly of block copolymers alone usually results in poly-grain structures. Directed self-assembly is an excellent technique developed rapidly in the past decade. Directed self-assembly either by graphoepitaxy with topographical guides or chemical registration with chemically pattered surfaces enabled us to control orientation and alignment of block copolymer microdomains in thin film on a substrate. It is expected that this technique will further extend the resolution limit of the conventional photolithography. This article briefly review the directed self-assembly techniques.