Provided is a method of manufacturing a semiconductor device. The method includes forming isolated contact filling portions and an etch control portion, the isolated contact filling portions filling contact holes defined in a support layer and are spaced apart from each other in a first direction and a second direction perpendicular to the first direction and the etch control layer surrounding the isolated contact filling portions, forming an interconnection layer on the isolated contact filling portions and the etch control portion, and forming interconnection patterns by photo-etching the interconnection layer, the isolated contact patterns, and the etch control portion, the interconnection patterns being relatively narrow in the first direction and relatively wide in the second direction.