Technology Reliability Qualification of a 65nm CMOS Cu/Low-k BEOL Interconnect

During the development and qualification of a 300mm low-k/Cu back end of line (BEOL) technology, the long-term reliability of such interconnects including low-k time-dependent dielectric breakdown (TDDB), Cu electromigration (EM), Cu stress migration (SM), and Cu/low-k thermal behavior are rapidly becoming one of the most critical challenges. In this paper, a comprehensive reliability evaluation for 65nm Cu/low-k interconnects is reported and various reliability issues associated with process integration and material optimization during initial development stage are discussed. Finally, we demonstrate that with careful process and materials optimization, a superior interconnect reliability performance at the 65nm technology node can be achieved for 300mm fabrication. The projected reliability lifetimes of TDDB, EM, and SM meet the most stringent reliability targets and criteria