Abstract: The diffusion barrier performance of W/Mo-N films between Cu and Si was studied. Thin Mo-N film was deposited on Si （100） substrate by reactive sputtering. And the Cu/W thin films were deposited on the Mo-N film by direct current sputtering. Samples were subsequently annealed at different temperatures in vacuum condition. The thermal stability of Cu/W/Mo-N/Si and the dif- fusion barrier performance of W/Mo-N films were characterized by four-point probe measurement, X-ray diffractometry, scanning electron microscopy and Auger electron spectroscopy analyses. The results reveal that the Cu/W/Mo-N/Si structure has a good thermal stability, and the W/Mo-N films are able to prevent the diffusion reaction between Cu and Si substrate annealed at 600oC for 30 min.