Impact of Anode-side Defect Generation on Inter-Level TDDB Degradation in Cu/Low-k Damascene Structures

We investigated the inter-level time-dependent dielectric breakdown (VTDDB) degradation mechanisms in Cu/low-k damascene structures. Considering the dependence of VTDDB reliability and ILD film properties on the post etching treatment (PET) condition, it was found that defect generation near the anode-side interface impacts the VTDDB lifetime and that the absolute value of the lifetime could be improved by reducing the number of Si-H bonds near the anode side. On the other hand, the electric field acceleration factor is independent of the anode-side defects, which is discussed based on the "Impact Damage model." Furthermore, we demonstrated experimentally the relationship between the intra-level TDDB (LTDDB) and the VTDDB failure mechanisms.