A Novel Resistivity Measurement Technique for Scaled-down Cu Interconnects Implemented to Reliability-focused Automobile Applications

A novel resistivity measurement technique has been proposed for scaled-down Cu interconnects viewing the high-reliability automobile applications. This technique enables to detect the interconnect resistivity dependence on impurity concentration, free from dimension dependence. Using this technique, we investigated impacts of impurity concentration on three types of Cu interconnects: 1) CoWP cap; 2) PECVD self-aligned barrier (PSAB); and 3) CuAl interconnects and clarified the tradeoffs between resistivity and reliability. We have found that CoWP cap shows not only high-reliability but also an outstanding efficiency in suppression of resistance increase due to impurity-induced scattering, indicating that it is the most viable candidate for automobile applications in 32nm generation and beyond