Abnormal ESD Damages Occur in Interface Circuits between Different Power Domains in ND-Mode MM ESD Stress

Complex ESD failure mechanisms have been found in the interface circuits of an IC product with multiple separated power domains. The MM ESD robustness can not achieve 150 V in this IC product with separated power domains, although it has the 2-kV HBM ESD robustness. The ND-mode MM ESD currents were discharged by circuitous current paths through interface circuits to cause the gate oxide damage, junction filament, and contact destroy of the internal transistors. The detailed discharging paths of each ND-mode ESD failure were analysed in this paper