A semiconductor device including a first interconnection line having a first end and extending in a first direction; a first blocking pattern at the first end of the first interconnection line and adjacent to the first interconnection line in the first direction; a second interconnection line spaced apart from the first interconnection line in a second direction crossing the first direction and extending in the first direction, the second interconnection line having a second end; and a second blocking pattern at the second end of the second interconnection line and adjacent to the second interconnection line in the first direction, wherein a width of the first blocking pattern in the first direction is different from a width of the second blocking pattern in the first direction.