铜互连微结构无籽晶RuMoC扩散阻挡层稳定性研究

Characterization of thermal stability of RuMoC films as seedless Cu diffusion barriers in damascene structures for Cu interconnects

摘要:

采用磁控共溅射Ru和MoC靶，通过调节掺入MoC的含量获得非晶态RuMoC薄膜，研究了非晶RuMoC薄膜的热稳定性。HRTEM和XRD结果表明，在500℃下RuMoC薄膜依旧保持非晶结构；XPS分析结果表明，在该温度下，Ru-C键依旧保持完好，是RuMoC薄膜良好热稳定的关键。此外，研究了RuMoC在大马士革铜互连线微结构中的热稳定性。HRTEM结果表明，RuMoC薄膜实现直接电镀铜，TEM原位EDS结果表明，RuMoC薄膜在500℃下依旧成功阻挡了Cu原子扩散。

Abstract:

The objective of this study is to test the feasibility of RuMoC films for its application in seedless Cu diffusion barriers of damascene structure. The compatibility with IC fabrication and thermal stability of RuMoC barriers were investigated. The RuMoC barriers were amorphous at temperatures up to 500 ℃, showing great thermal stability. This is because the Ru-C bonds were well preserved at those temperatures, as revealed by XPS results, which hindered the Ru from crystallizing. A Cu plug of good quality was successfully electroplated on RuMoC barriers and filled the trench without seed layer, and the barrier effectively blocked the diffusion of Cu atom at temperatures up to 500 ℃. The results indicated a great prospect of RuMoC film as seedless Cu diffusion barrier in damascene structure for Cu interconnect.