Structural evolution of Zr-Cu-Ni-Al-N thin film metallic glass and its diffusion barrier performance in Cu-Si interconnect at elevated temperature

In this study, a Zr-Cu-Ni-Al-N thin film metallic glass (TFMG) has been developed and applied for the diffusion barrier between copper and silicon. The Si/TFMG/Cu stacked structures with various TFMG thickness have been fabricated. Rapid thermal annealing was conducted at 500, 600, 700 and 800 °C. The X-ray diffraction analysis was applied to identify the formation of Cu3Si intermetallic compound. The Electron Spectroscopy for Chemical Analysis (ESCA) depth profile was executed to quantitatively evaluate the degree of Cu-Si inter-diffusion. With the aid of HR-TEM, the microstructure of the stack could be observed. It is shown that a 10-nm-thick TFMG thin film barrier is capable of retarding the Cu-Si inter-diffusion under 700 °C. The degree of Cu-Si diffusion is strongly related to the structural evolution of TFMG annealed at various temperature. The thickness of TFMG also exhibits a positive effect on barrier performance. Finally, the correlation between microstructure, thermal properties, thickness and barrier performance of the TFMG will be revealed and established.