The inventive concept provides methods for forming fine patterns of a semiconductor device. The method includes forming a buffer mask layer having first holes on a hard mask layer including a first region and a second region around the first region, forming first pillars filling the first holes and disposed on the buffer mask layer in the first region and second pillars disposed on the buffer mask layer in the second region, forming a block copolymer layer covering the first and second pillars on the buffer mask layer, phase-separating the block copolymer layer to form first block patterns spaced apart from the first and second pillars and a second block pattern surrounding the first and second pillars and the first block patterns, removing the first block patterns, and forming second holes in the buffer mask layer under the first block patterns.