Abstract
TiN with Multilayered Structure and TaN as Diffusion Barrier for Cu Metallization Abstract In this research, a novel multilayered Ti/TiN diffusion barrier was proposed applied for Cu metallization. TiN film displays column structure after PVD sputtering, and the grain boundaries between two column grains becom fast diffusion path and hence alleviates the interdiffusion between metal and silicon. So we try to add one or more Ti layers into TiN film to block the continuity of column structure, and raise the difficulty of copper diffuse into silicon in high temperature. From TEM images, it was found that TiN grain boundary was discontinuous while a Ti layer was inserted in TiN. Leakage current analyze under different temperature, the result show that multilayered Ti/TiN enhance the thermal stability and has better performance. The effect of more Ti layers were better than one Ti layer, but when The thickness of Ti layer were too thin, the improvement was not very obviously. In this research also discuss the oxygen content in TiN thin film. Oxygen content in grain boundaries made the microstructure more amorphous, and also improve the barrier performance. On the other hand, tantalum nitride was reactively sputtered by various nitrogen/argon flow ratios. It was found that microstructure of tantalum nitride become more and more amorphous with increasing nitrogen flow ratio. And the result of leakage current analyzes under different temperature also show that better barrier performance with increasing nitrogen flow ratio. Except leakage current discuss, XRD, SEM, RBS, AES were used for material characterization to make this experiment more precisely and completely .