Reliability investigation of NiPtSi electrical fuse with different programming mechanisms

The reliability of NiPtSi/p-poly Si electrical fuses with different programming mechanisms, i.e. electromigration and thermal rupture, was investigated in terms of fuse resistance stability and fuse array functionality, for 65 nm technology node. The resistance of the fuses programmed within the electromigration programming window, were found to be very stable; resistance shift was only observed on fuses programmed in the under-programmed mode which results in incomplete electromigration. For fuses programmed with the thermal rupture mechanism, both resistance shift and functional sensing fails were observed. Furthermore, a guard band was defined for fuses programmed with electromigration mechanism, to ensure sufficient margins for fuse reliability. However, a guard band can not be defined for fuses programmed with rupture mode, due to the unpredictable nature of the rupture programming mechanism. The unprogrammed fuse elements were shown to be stable through extensive reliability evaluations.