Method of manufacturing semiconductor device

A method of manufacturing a semiconductor device, comprising:

• forming a plurality of word lines on a substrate, the word line extending in a first direction and spaced apart from each other in a second direction perpendicular to the first direction;
• forming an interlayer insulating layer on the word lines and the substrate;
• forming direct contact holes between the word lines by etching the interlayer insulating layer and the substrate, the direct contact holes spaced apart from each other in the first direction and the second direction;
• forming isolated contact filling portions filling the direct contact holes and an etch control portion physically connected to and covering top surfaces of the isolated contact filling portions by depositing a contact interconnection layer;
• forming an interconnection layer on the isolated contact filling portions and the etch control portion;
• and
• forming a bit line and a direct contact pattern on the direct contact holes and the interlayer insulating layer by photo-etching the interconnection layer, the isolated contact filling portions, and the etch control portion, the bit line and the direct contact pattern being relatively narrow in the first direction and relatively wide in the second direction.