Preparation of WNx films and their diffusion barrier properties in Cu/Si contact systems

We prepared thin WNx films with various compositions by reactive sputtering and examined their characterizations and barrier properties applied to Cu/WNx/Si contact systems. The results indicate that the W65N35 barrier, which is in the W2N phase with preferred orientation in the (111) plane, shows excellent barrier properties for Cu metallization. The obtained Cu/W2N/Si system is fairly stable without diffusion and/or reaction even after annealing at 800 degrees C for Ih. This system stability is speculated to originate from the thermal stability of the W2N film itself, which is chemically inert and scarcely changes in structure due to annealing.