Cu互连中Zr嵌入层对ZrN阻挡层热稳定性的影响

Effect of Insertion of a Thin Zr Interlayer on Thermal Stability of ZrN Barrier in Cu Metallization

在不同的衬底偏压下,用射频反应磁控溅射的方法在Si(100)衬底和Cu膜间制备了ZrN/Zr/ZrN堆栈结构的阻挡层。研究了Zr层的插入对ZrN扩散阻挡性能的影响,结果表明:随着衬底偏压的升高,阻挡层的电阻率降低,ZrN呈(111)择优取向;Zr层的插入使ZrN阻挡层的失效温度至少提高100℃,750℃仍能有效地阻止Cu的扩散,阻挡性能提高的主要原因可能是高温退火时形成的ZrO2阻塞了Cu快速扩散的通道。

ZrN/Zr/ZrN diffusion barrier was grown on Si （100） substrates under different substrate bias in a RF magnetron sputtering system. The effect of insertion of a thin Zr interlayer between Zr-N films on Zr-N diffusion barrier performance in Cu metallization was investigated. The results reveal that an increase in negative substrate bias results in a decrease in the resistivity together with a higher ZrN （111） preferred orientation. The barrier breakdown temperature of ZrN/Zr/ZrN film is about 100 ℃ higher than that of ZrN. It can effectively prevent the diffusion of Cu after annealing at 750 ℃. The improvement of diffusion barrier performance is due to that the production of ZrO2 blocks the diffusion paths of Cu when annealing at high temperature.