Application of Zr-Si film as diffusion barrier in Cu metallization

The diffusion barrier's performance of Zr-Si film in CuSi contacts has been investigated. CuZr-SiSi contact system was deposited by using radio frequency reactive sputtering technique. Annealing studies for CuZr-SiSi were then carried out in nitrogen to investigate Cu diffusion and barrier film crystallization. The contact system was characterized by using four-point probe sheet resistance measurements, X-ray diffraction, scanning electron microscope, and Auger electron spectroscopy (AES), respectively. It is observed that the sheet resistance of CuZr-SiSi contact system is lower than that of as-deposited specimens even after annealing at 700°C. The CuZr-SiSi contacts tolerated annealing at 800°C for an hour without structural change of the barrier. AES depth profiles of the annealed CuZr-SiSi samples are similar to each other and have no intermixing evidence. Zr-Si was found to be a promising diffusion barrier material for Cu metallization.