A semiconductor device has improved reliability by preventing a fuse cut through a repair process from being electrically reconnected by electrochemical migration. The semiconductor device includes a substrate, a fuse including a first fuse pattern and a second fuse pattern formed at the same level on the substrate, the first fuse pattern and the second fuse pattern being spaced a first width apart from each other such that a gap in the fuse is disposed at a first location between the first fuse pattern and the second fuse pattern, and a first insulation layer formed on the first fuse pattern and the second fuse pattern, the first insulation layer including an opening above the first location and having a second width smaller than the first width.