Failure mechanism of thin VN barrier between Cu interconnects and SiO{sub}2 layer

摘要

As a thin barrier applicable in the 90 nm rule metallization, the VN thin barrier with ～10 nm in thickness was examined from the point of view of the barrier properties and the failure mechanism of the Cu/VN/SiO{sub}2/Si system. The system showed the excellent thermal stability after annealing at 600℃ or higher for 1 h without structural change of the barrier and interfacial reaction in the system upon annealing. This is because the VN barrier has excellent properties in chemical stability and in structural stability. The further annealing up to 800℃ for 1 h led to the grain growth of the barrier in the lateral direction, resulting in the interdiffusion between the Cu interconnects and SiO{sub}2 layers. The Cu/VN/SiO{sub}2/Si system was fairly stable until the annealing temperature at which lateral grain growth of VN barrier led to the failure of continuity of the barrier.