Reliability performance of advanced metallization options for 30nm ½ pitch in SiCOH low-k materials

Metallization options to fill 30nm ½ pitch trenches have been explored and their Time-Dependent-Dielectric-Breakdown (TDDB) and electromigration (EM) performance have been benchmarked to the conventional PVD TaNTa / PVD Cu seed based metallization. CVD Co as seed enhancement layer shows no deterioration in TDDB performance and improved EM performance, but the activation energy for EM was 0.68±0.20eV, which is at the lower end of the expected value of 0.85–0.95eV for this parameter. PVD RuTa barriers with 90%Ru and 10%Ta show degraded barrier performance and significant lowering of activation energy for EM (0.59±0.05eV). Finally, it is shown that, using an optimized PVD Cu seed, standard PVD TaNTa-barriers give excellent TDDB performance and that typical EM lifetime specs can be met with this metallization scheme down to 30nm ½ pitch.