Application of Zr-Si Film as Diffusion Barrier in Cu Metallization

The diffusion barrier’s performance of Zr - Si film in Cu ∕ Si contacts has been investigated. Cu ∕ Zr - Si ∕ Si contact system was deposited by using radio frequency reactive sputtering technique. Annealing studies for Cu ∕ Zr - Si ∕ Si 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 Cu ∕ Zr - Si ∕ Si contact system is lower than that of as-deposited specimens even after annealing at 700°C. The Cu ∕ Zr - Si ∕ Si contacts tolerated annealing at 800°C for an hour without structural change of the barrier. AES depth profiles of the annealed Cu ∕ Zr - Si ∕ Si 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.