Fabrication and laser deletion of microfuses

摘要

A method of fabricating a microfuse, deletable by laser pulses utilizes laser pulses of a predetermined spot diameter and beam alignment accuracy. A fusible link forming a portion of the microfuse is defined such that its length is at least equal to the sum of the laser spot diameter and the beam alignment accuracy and its width is no greater than half the laser spot diameter. A method of deleting the microfuse by laser pulses is provided where the microfuse has a predetermined composition, length and width having an axis bisecting the width and parallel to the length and is covered with a passivation layer at least 3 mu m thick. The method includes adjusting the diameter of the beam of laser light (i) to at least a minimum diameter of W+ DELTA Pw, where W equals the width of the microfuse fuse link and DELTA Pw equals the accuracy of the beam in the direction of W and (ii) to no more than a maximum diameter of L+ DELTA PL, where L equals the length of the microfuse fuse link and DELTA PL equals the accuracy of the beam in the direction of L.