Methods of fabricating a semiconductor integrated circuit device are disclosed. The methods of fabricating a semiconductor integrated circuit device include forming a hard mask layer on a base layer, forming a line sacrificial hard mask layer on the hard mask layer in a first direction, coating a high molecular organic material layer on the line sacrificial hard mask layer pattern, patterning the high molecular organic material layer and the line sacrificial hard mask layer pattern in a second direction, forming a matrix sacrificial hard mask layer pattern, forming a hard mask layer pattern by patterning the hard mask layer with the matrix sacrificial hard mask layer pattern as an etching mask and forming a lower pattern by patterning the base layer using the hard mask layer pattern as an etch mask. The method according to the invention is simpler and less expensive than conventional methods.