Provided are a semiconductor device including a fuse focus detector, a fabrication method thereof and a laser repair method. In a chip region, fuses may be formed at a first level. A fuse focus detector including first and second conductive layers may be formed in a scribe line region. The first conductive layer may be formed at the first level, while the second conductive layer may be formed at a different level. For a laser repair method, a target region may be divided into sub-regions. In one selected sub-region, the fuse focus detector may be laser scanned in a direction for a reflection light measurement providing information on a thickness of the fuse focus detector. Using the thickness information, a focus offset value of a fuse in the selected sub-region may be calculated. When the focus offset value is within an allowable range, fuse cutting may be performed.