Method of forming fine line patterns of semiconductor devices

A method of forming fine line patterns, the method comprising:

• forming a plurality of lower linear core structures on at least one lower hard mask layer disposed on a target layer;
• forming a spacer layer on the lower hard mask layer to cover the lower linear core structures;
• forming an upper hard mask layer on the spacer layer;
• thinning the upper hard mask layer until potions of the spacer layer are exposed;
• and
• removing the exposed portions of the spacer layer until potions of the lower hard mask layer are exposed, so as to form a plurality of line patterns on the lower hard mask layer.