Parametric and numerical study on the diffusion in a metalized amorphous binary alloys film

An amorphous Ta-Zr diffusion barrier was studied under the Cu metallization. A stack of Cu/Ta50Zr50/Si with a 50 nm amorphous film fabricated by co-sputtering was found to fail when annealed up to 650 °C, which is much lower than the crystallization temperature (800 °C) of the amorphous Ta50Zr50 film. Besides, results show that the existence of Cu layer can induce the formation of three metal silicides, namely TaSi2, ZrSi2 and Cu3Si almost all at 650 °C. A mechanism for the failure of barrier film is proposed based on the change of activation energy for diffusion by the metallization-induced tensile stresses during annealing.