Effect of TSV – Keep Out Zone on BEOL Reliability of HBM3E

This study investigates the impact of the Keep-Out Zone (KOZ) distance on the BEOL reliability of HBM3E chips, presenting quantitative results not previously reported. While prior research has explored TSV-induced stress effects on FEOL and BEOL, the impact on metal layers has generally been considered minor. In this study, significant degradation in EM and IMD TDDB properties was observed as the KOZ distance decreased. The extent of degradation varied depending on KOZ distance and design layout but can be mitigated through process optimization and layout restrictions for adjacent metals/layers in HBM3E. Chip level tests confirmed that proper design and process control ensure minimal risk to the reliability of final chips. These findings suggest that mechanical stress induced by TSV and MLM tech shrink has begun to affect BEOL reliability in the KOZ region.