Characteristics of sputtered TaBx thin films as diffusion barriers between copper and silicon

Thin films of TaBx interposed between Cu and Si are examined here as diffusion barriers for Cu metallization. In order to investigate the performance of Cu/TaBx/Si contact systems, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), sheet resistance measurement, scanning electron microscopy (SEM), cross-sectional transmission electron microscopy (XTEM), and Auger electron spectroscopy (AES) depth profile were used. Results of this study indicate that the barrier characteristics are significantly affected by the B/Ta ratio. In addition, the failure mechanism for the Cu/TaBx/Si contact systems is also discussed herein.