PLASMA TREATMENT OF THERMAL CVD TAN FILMS FROM TANTALUM HALIDE PRECURSORS

A plasma treated chemical vapor deposition (PTTCVD) method for depositing high quality conformal tantalum nitride (TaNx) films from inorganic tantalum halide (TaX5) precursors and a nitrogen containing gas is described. The inorganic tantalum halide precursors are tantalum pentafluoride (TaF5), tantalum pentachloride (TaCl5) and tantalum pentabromide (TaBr5). In a thermal CVD process, a TaX5 vapor is delivered into a heated chamber. The vapor is combined with a process gas containing nitrogen to deposit a TaNx film on a substrate that is heated to 300° C.-500° C. A hydrogen gas is introduced in a radiofrequency generated plasma to plasma treat the TaNx film. The plasma treatment is performed periodically until a desired TaNx film thickness is achieved. The PTTCVD films have improved microstructure and reduced resistivity with no change in step coverage. The deposited TaNx film is useful for integrated circuits containing copper films, especially in small high aspect ratio features. The high conformality of these films is superior to films deposited by PVD.