Preparation of ultrathin TiNx films by radical assisted low temperature deposition and their barrier properties against Cu diffusion

Abstract We examine characterization and barrier properties of the TiN x films prepared by an original deposition method, which consists of conventional sputtering and radical treatment. This method realizes the low-temperature deposition of the diffusion barriers applicable to Cu-through silicon via (TSV) in the three-dimensional large scale integration (3D-LSI) of wafer on wafer process. We can successfully prepare the TiN x films of low resistivity and high density at a temperature lower than 200 °C. The 5-nm-thick TiN x films as the diffusion barrier for Cu-TSV show sufficient performance to the thermal stress without interface layers owing to solid-phase reaction and intermixing after annealing at 500 °C for 30 min at both Cu/TiN x and TiN x /SiO 2 interfaces. The proposed method in this study is a candidate process for depositing the transition metal nitride film at low temperatures in the 3D-LSI.