Electromigration early failure distribution in submicron interconnects

The early failure issue in electromigration (EM) has been an unresolved subject of study over the last several decades. A satisfying experimental approach for the detection and analysis of early failures has not yet been established. In this study, a new technique utilizing large interconnect arrays in conjunction with the well-known Wheatstone bridge is presented. A total of more than 20,000 interconnects were tested. The results indicate that the EM failure mechanism studied here follows log-normal behaviour down to the 4 sigma level.