New strategy of nanolithography via controlled block copolymer self-assembly

The self-assembly of block copolymer-homopolymer blends in bulk, as well as under the direction of periodic patterned surfaces, has been investigated by computer simulations of the time-dependent Ginzburg-Landau theory. Specifically, a small amount of homopolymers are added to regulate the spontaneous nucleation rate and substrate patterns are designed to control the position and orientation of the induced nuclei. The mechanism, validity and efficiency of this scheme is examined using 2D and 3D computer simulations of cylinder-forming block copolymer-homopolymer blends, demonstrating that large-scale perfectly ordered patterns can be produced by controlling the position and orientation of induced multiple nucleation events. This scheme, combining the nucleation event of block copolymer self-assembly with the direction of the patterned surface, can be used in the lithography technique of block copolymers to significantly improve the directing efficiency, i.e., the density multiplication.