A method of forming patterns for a semiconductor device. The method includes: forming a first hard mask layer on a layer which is to be etched; forming a second hard mask layer on the first hard mask layer, wherein the second hard mask layer includes a first portion and a second portion formed underneath the first portion, wherein the first portion and second portion are composed of the same material; etching the first portion to form first patterns; forming spacers covering sidewalls of the first patterns; etching the second portion using the spacers as etch masks to form second patterns; etching the first hard mask layer and the spacers using the second patterns disposed underneath the spacers as etch masks to form third patterns; and etching the layer to be etched, using the third patterns.