A method includes forming a template portion to provide a first opening trench portion surrounding a first isolated pattern, and forming an array of pillars on an underlying layer; forming a separation wall layer including first separation wall portions surrounding sidewalls of the pillars, and forming second separation wall portions covering sidewalls of the first opening trench portion; forming a block copolymer layer on the separation wall layer; forming first domains in gaps between the pillars, and forming second domains surrounding and separating the first domains by annealing the block copolymer layer; forming second openings by selectively removing the first domains; forming third openings between the second openings, and forming a fourth opening adjacent to the first isolated pattern by selectively removing the pillars and the template portion; and forming fifth openings, which extend from the second and third openings and penetrate the underlying layer, and forming a sixth opening, which extends from the fourth opening and penetrates the underlying layer.