Property improvement of Cu-Zr alloy films with ruthenium addition for Cu metallization

Films of Cu-Ru-Zr and Cu-Zr were deposited on SiO2/Si substrates by magnetron sputtering. Samples were subsequently annealed at temperatures of up to 500 °C for 1 h and analyzed by four-point probe measurement, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy. The XRD data suggest that the Cu film has a preferential (1 1 1) crystal orientation. According to the TEM results the grain size of the alloy Cu film is smaller than that of a pure Cu film. XPS indicates that a ZrOx layer has formed at the Cu alloy/SiO2 interface and that its thickness in the annealed Cu-Ru-Zr/SiO2/Si sample becomes larger due to Ru incorporation. After annealing the resistivity values of the annealed Cu alloy films are a little higher than that of annealed pure Cu film. These results indicate that Cu-Ru-Zr films are suitable for advanced barrier-free metallization from the view of interfacial stability and low resistivity.