Investigation of Ru/TaN on low dielectric constant material with k=2.7

The properties of the ruthenium (Ru)/ TaN as copper diffusion barrier in copper low dielectric constant material(low-k) metallization were studied by sheet resistance, X-ray diffraction (XRD), X-ray photoelectron spectroscopy(XPS), transmission electron microscopy (TEM) and electrical current leakage-voltage tests. Cu, Ru and TaN thin films were deposited by ion beam sputtering technique. Sheet resistance and XRD results demonstrate that there was little inter-diffusion with ascending annealing temperatures. The XPS spectra indicate that Ru was partially oxidized and no inter reaction with low-k was observed. TEM images show that copper appeared into barriers when the sample was annealed at 400degC/30min, and it is revealed that copper diffused into low-k at 500degC/30min from the I-V test