Passive Voltage Contrast Investigation of Metal/Via Stack Connecting to Substrate

In this paper, a detailed study of passive voltage contrast on a metal/via/active chain ET structure is performed. Both electron-beam and ion-beam based PVC techniques are tried with different experimental settings. It is found that electron-beam based PVC cannot provide significant contrast at the failure site. The ion-beam based PVC successfully isolates the failure location. Moreover, some interesting PVC contrast changes with different settings are also observed. FIB cross section reveals the failure mechanism. Based on the failure mechanism and theoretical models, the observed PVC contrast can be explained.