Interface stability and microstructure of ultrathin Mo/MoN diffusion barrier in Cu interconnects

作者：C. H. Liu, Yongzhong Jin, Xuejun Cui, Rui Yang, Qingshan Fu, L. Wang, J. Tang, Siyi Ye · 发表于：Materials Research Innovations · 年份：2013 · DOI：10.1179/1432891713z.000000000184 · 被引用次数：3 · 研究领域：Copper Interconnects and Reliability、Metal and Thin Film Mechanics、Semiconductor materials and devices

An ultrathin Mo (7 nm)/MoN (3 nm) bilayer film covered by Cu film was deposited on the Si substrate using reactive magnetron sputtering in N2/Ar ambient. The film stacks of Cu/Mo (7 nm)/MoN (3 nm)/Si were then annealed in a vacuum chamber at 500–800°C for 1 h. X-ray diffraction, scanning electron microscopy, cross-sectional transmission electron microscopy and energy dispersive X-ray spectroscopy line scans were employed to investigate the microstructure evolution and the diffusion behaviour of the film stacks. The results show that the Mo (7 nm)/MoN (3 nm) bilayer film as a diffusion barrier has sufficient interface stability, which can prevent Cu atom diffusion at elevated temperatures up to 700°C. The relationship between the interface stability and the microstructure of the bilayer barrier is characterised in detail.