磁控溅射的TaN薄膜的扩散阻挡性能

Performance of RF Sputtering Deposited TaN as the Diffusion Barrier of Cu Interconnection

用反应磁控溅射方法在SiO2/Si(100)衬底和Cu薄膜间溅射一层TaN阻挡层,测试不同N气分压及热处理温度下Cu/TaN/SiO2/Si薄膜的显微结构和电阻特性。同时利用微细加工技术加工了镂空的Cu互连叉指测试结构,研究了TaN薄膜在镂空的铜互连结构中的扩散阻挡性能。结果发现,在退火温度不超过400℃时,薄膜电阻率均低于80μΩ.cm,而当溅射N分压超过10%,退火温度超过400℃时,薄膜电阻率很快上升。低N气分压下(≤10%)溅射时,即使退火温度达到600℃,薄膜电阻基本不变。

A 30 nm thick TaN diffusion barrier layer between Cu thin film and SiO2/Si （100） substrate was deposited by reactive RF sputtering under different nitrogen pressures. The nanoscale images of Cu surface and the resistivity change of the Cu/TaN/SiO2/Si interconnection were examined after annealing at 200 650 ℃. A fork test structure for free-standing copper interconnects was fabricated, and the diffusion barrier performance of TaN thin film was examined. The electrical tests indicate that the resistivity of the thin films was less than 80 μΩ· cm when the temperature was less than 400 ℃. Cu lines with the TaN barriers deposited with nitrogen pressure 10% exhibit better thermal stability than those Cu line with TaN barriers deposited above 10 % nitrogen pressure.