Characteristics of ALD-TaN thin films using a novel precursors for copper metallization

ALD-TaN thin films derived from tert-buthyIimidotrisdiethyl-amidotantalum (TBTDET) and tert-amylimidotrisdim-ethylamidotantalum (TAIMATA) precursors for the diffusion barrier in Cu interconnects were developed. The deposition rate of the ALD-TaN process was saturated at 0.4 /spl Aring/ /cycle in a temperature range between 200/spl deg/C and 250/spl deg/C with TBTDET and at 0.2 /spl Aring//cycle in a temperature range between 150/spl deg/C and 200/spl deg/C with TAIMATA. Both precursors provided roughly comparable film properties such as not only excellent conformality but also composition and structure characterized by XPS and XRD, respectively. ALD-TaN films obtained from above precursors yield low via resistance in aluminum interconnects. However, relatively high via resistance was resulted upon Cu integration as compared to PVD-TaN and Al metallization. The superior diffusion barrier characteristic on Cu metallization was observed with ALD-TaN by BTS result in comparison to the conventional PVD-TaN.