Abstract
To fulfill the strict demands for Cu interconnects below 65nm, a 10nm-thick (TiVCr)N film with ternary metallic elements was developed in this study as a candidate diffusion barrier by reactive sputtering in an N 2 /Ar mixed atmosphere. Barrier properties were examined by annealing over a temperature range of 700-900°C for 30min. From the analyses of diffusion behaviors after thermal annealing at 700°C, the electrical resistance of the Si/(TiVCr)N/Cu film stack remained as low as the as-deposited value. No interdiffusion between the Si substrate and the Cu metallization was found through the (TiVCr)N film at temperatures as high as 700°C. After annealing at 800°C, the penetration of a partial number of Cu atoms through the (TiVCr)N barrier occurred and thus some Cu silicides were formed. With temperature further increased to 900°C, severe interdiffusion of Si and Cu through the layer occurred and induced the formation of a large amount of Cu silicides. This demonstrates that TiVCr ternary refractory metal nitrides have potential use as effective diffusion barriers for copper metallization. © 2011 Elsevier B.V.