Performance Improved by Incorporating of Ru Atoms into Zr-Si Diffusion Barrier for Cu Metallization

Thin Ru₂₁Zr₆₄Si₁₅ films deposited on Si substrates by radio frequency reactive magnetron sputtering are studied and evaluated as diffusion barriers for Cu metallization. Cu/Ru₂₁Zr₆₄Si₁₅/Si and Cu/Zr₆₇Si₃₃/Si structure samples are prepared under the same procedures for comparison. The thermal stability, phase formation, surface morphology and atomic depth profile of the Cu/Ru₂₁Zr₆₄Si₁₅/Si and Cu/Zr₆₇Si₃₃/Si structures before and after annealing at different temperatures are investigated. In conjunction with these analyses, the Cu/Ru₂₁Zr₆₄Si₁₅/Si contact system shows high thermal stability at least up to 650°C. The results obtained reveal that the incorporation of Ru atoms into the Zr₆₇Si₃₃ barrier layer is shown to be beneficial for improving the thermal stability of the Cu/barrier/Si contact system.