Local Electric Field-Aware 3D TDDB Model for BEOL Reliability Predictions

We present a novel 3D Time Dependent Dielectric Breakdown (TDDB) model that accounts for non-uniform electric fields near lines and vias (i.e. corner effects) and its related impact on the local defect generation dynamics. Our Local Electric Field-Aware Model (LEFAM) is calibrated with TDDB data from parallel-plate capacitors, enabling the extraction of intrinsic reliability properties of BEOL dielectrics. We show that LEFAM can predict the impact of geometry variations, such as Line-Edge-Roughness or Via-Misalignment, affecting the local E-field in the dielectric. Finally, we compare LEFAM to our previous model, which relied on the conventional parallel-plate E-field approximation. Due to the fact that final breakdown happens at locations where the E-field is significantly lower than the parallel-plate E-field, LEFAM predicts higher Weibull scale parameters η. Due to its higher flexibility in defect generation position, LEFAM predicts a higher dependency of the Weibull slope ß on variability, finally resulting in similar predicted lifetimes at lower percentiles for both models. Where these findings are valid for lower amounts of variability, the bigger discrepancies between the different models for higher amounts of variability require future investigation.