Temperature and field interrelation study of low-k TDDB for Cu interconnects with and without liner - New insights to the roles of Cu for a competing breakdown process

Low-k time dependent dielectric breakdown (TDDB) is commonly considered an important reliability issue. It has been proposed that there is an interrelation of field and temperature dependence between TDDB thermal activation energies and field acceleration parameters, which could provide a more comprehensive picture to understand low-k TDDB breakdown mechanism. In this study, an extensive investigation of low-k TDDB degradation at 32nm over a wide range of fields and temperatures was conducted for Cu interconnects with and without regular TaN/Ta liner. New interrelations of field and temperature dependence between TDDB thermal activation energies and field acceleration parameters for Cu samples with and without liner were experimentally identified, which provide a new insight to roles of Cu in low-k TDDB breakdown model.