Experimental confirmation of electron fluence driven, Cu catalyzed interface breakdown model for low-k TDDB

During technology development, the study of low-k TDDB is important for assuring robust chip reliability. It has been proposed that the fundamentals of low-k TDDB are closely correlated with the leakage conduction mechanism of low-k dielectrics. In addition, low-k breakdown could also be catalyzed by Cu migration occurring mostly at the interface between capping layer and low-k dielectrics. In this study, we conducted several important experiments including leakage modulation by changing the capping layer without changing the electric field, TDDB modulation by liner-free interconnect build, 3D on-flight stress-induced leakage current (SILC) measurement, triangular voltage sweep (TVS) versus TDDB, and Cu-free interconnect build at 32nm to experimentally confirm the proposed electron fluence driven, Cu catalyzed interface low-k breakdown model.