The characterization of Zr–Si–N diffusion barrier films with different sputtering bias voltage

Abstract

Zr–Si–N diffusion barriers were sputtered by RF reactive magnetron sputtering with different bias voltage. The Cu films were subsequently sputtered onto the Zr–Si–N films without breaking vacuum. Energy dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Auger electron spectroscopy, transmission electron microscopy, atomic force microscope, and four-point probe method were employed to characterize the microstructure and properties of the Zr–Si–N films. The results reveal that as the bias voltage increases the Zr/Si ratio and the surface roughness increase, but the resistivity of the film decreases. High sputtering bias is in favor of the growth of ZrN grains in Zr–Si–N film. With the decrease of sputtering bias, the microstructure of Zr–Si–N film changes from composite consisting of nano-grain ZrN and amorphous SiN x to one consisting of amorphous phases of both ZrN and SiN x . The Zr–Si–N film can effectively prevent diffusion of Cu to Si wafer even at high temperature of 850 °C.