Advanced XPS depth profiling analysis of metal alloys as diffusion barriers for Cu interconnects

X-ray photoelectron spectroscopy - depth profiling (XPS - DP) is an underutilized technique for examining the diffusion behavior of interconnect materials, despite its potential to provide valuable insights into diffusion mechanisms and failure causes. In this study, we employ XPS - DP to investigate the diffusion of copper (Cu) into various potential metal alloy diffusion barriers. Furthermore, we will show, how the Mixing-Roughness-Information depth (MRI) model can be utilized to extract diffusion coefficients and activation energies.