Structure and programming of laser fuse

摘要

A method and structure for fabricating a laser fuse and a method for programming the laser fuse. The laser fuse includes a dielectric layer having two vias filled with a first self-passivated electrically conducting material. A fuse link is on top of the dielectric layer. The fuse link electrically connects the two vias and includes a second material having a characteristic of changing its electrical resistance after being exposed to a laser beam. Two mesas are over the fuse link and directly over the two vias. The two mesas each include a third self-passivated electrically conducting material. The laser fuse is programmed by directing a laser beam to the fuse link. The laser beam is controlled such that, in response to the impact of the laser beam upon the fuse link, the electrical resistance of the fuse link changes but the fuse link is not blown off. Such electrical resistance change is sensed and converted to digital signal.