Nitrogen impurity effects of W–B–C–N quaternary thin film for diffusion barrier for Cu metallization

To investigate the thermal stability of nitrogen stuffing effect of tungsten–boron–carbon–nitrogen (W–B–C–N) thin diffusion barrier, the binding energy shift was studied for various annealing temperature. The X-ray diffraction patterns, the deposition rates and the resistivities of W–B–C–N thin film were measured as a function of nitrogen gas ratios for various annealing temperatures and the binding energy between tungsten and nitrogen was determined by the X-ray photoemission spectroscopy. The interface of Cu/W–B–C–N/Si multilayer was characterized for various nitrogen impurity concentration. Our experimental results indicate that W–B–C–N thin films are effective diffusion barriers to prevent the interdiffusion between Cu and Si interface after annealing up to 850 °C for 30 min.