There is provided a method of forming patterns for a semiconductor device. The method sequentially forming a first mask layer and a second mask layer on a substrate. The method also includes forming a second mask pattern layer by patterning the second mask layer. The method further includes forming a first mask pattern layer having a negative slope portion, by etching the first mask layer exposed through the second mask pattern layer. The method also includes forming a thin film layer on the substrate exposed through the first mask pattern layer.