This study attempts to form a TiN barrier layer against Cu diffusion by the easier and more convenient method. In this new approach, Ti was sputter-deposited, and nitrided by heat-treating in the NH$_3$ambient. Sheet resistance of as-deposited Ti was 20 Ω/$square$, but increased to 195 Ω/$square$ after the heat-treatment at 30$0^{circ}C$, and lowered to 120 Ω/$square$ after the heat-treatment at 50$0^{circ}C$, and $600^{circ}C$. AES results for these thin films confirmed that the atomic ratio of Ti and N was close to 1:1 at or above 40$0^{circ}C$ heat-treatment. However, it was also found that excessive oxygen was contained in the TiN layer. To examine the barrier property against Cu diffusion, 100nm Cu was deposited on the TiN layer and then annealed at 40$0^{circ}C$ for 40 min.. Cu remained at the surface without diffusing into the Si layer.