Multi-component AlCrTaTiZrMo-nitride film with high diffusion resistance in copper metallization

In this study, a multi-component AlCrTaTiZrMo-nitride film with a total thickness of about 10 nm have been investigated as a diffusion barrier layer for copper metallization. To achieve the diffusion barrier characteristic between Cu and Si, the Cu/AlCrTaTiZrMo-nitride/Si structure were annealed at temperatures from 700 °C to 900 °C for 1 h in high vacuum. Under annealing at high temperature of 800 °C, the layer still remained amorphous with nanocrystalline features, effectively retarded the interdiffusion between Cu and Si without the formation of any Cu-silicides. After annealing at 900 °C, Cu-silicides compound formed with the appearance of island-like surface, revealing that the interdiffusion occurred between Cu and Si. The findings indicate that HEA-nitride layer have excellent diffusion barrier performance before annealing at 900 °C. Its high diffusion barrier performance and thermal stability are probably attributable to the amorphous structure with nano-crystalline features, the simple solid solution structure, the multiple-element effects, and the high stacking density without rapid diffusion path.