Abstract: A micro fuse for use in a semiconductor device. The micro fuse comprises an insulating substrate and an elongate metal fuse member, the fuse member being supported at either end on the substrate and including at least one fuse region suspended out of contact with the substrate and shaped such that, in use, a predetermined current can be applied to it to make it non-conducting. At least one barrier may be formed between the fuse region of the fuse member and the insulator. The fuse member may be formed from a readily oxidisable metal, such as Titanium, Tungsten, Copper or Aluminum. The fuse member may have two or more fuse regions, with a region between adjacent fuse regions being supported by a metal track. In this case, the fuse member may also be supported on the substrate via one or more inter layers.