Thermally stable W-bit line technology for ULSI device application

We have investigated the various types of diffusion barriers for the thermally stable W-bit line structure. We estimated the thermal stability and the electrical characteristics of various barrier structures after annealing at 850/spl deg/C and then optimized the W-bit line process. A newly developed PVD-Ti/PVD-TiN/RTP/Strip/PVD-TiN/CVD-W structure showed good integrity with the W-bit line after high temperature processing. It is concluded that the prevention of oxygen penetration during silicidation is most important for the formation of a uniform silicide layer and better contact characteristics.