Ultrathin ( AlCrTaTiZr ) Nx / AlCrTaTiZr Bilayer Structures with High Diffusion Resistance for Cu Interconnects

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In this study, and films with quinary metallic elements were developed as diffusion barrier materials for Cu interconnects. To improve the interface adhesion to Cu, an AlCrTaTiZr buffer layer was deposited on the barriers to form and bilayer structures. The as-deposited AlCrTaTiZr and films were amorphous structures, and possessed a nanocomposite structure. After annealing at , although Cu penetrated into the AlCrTaTiZr buffer layer, the diffusion of Cu was retarded by the and barriers. During annealing at , the interdiffusion of Si and Cu occurred through the bilayer, and Cu silicides formed. However, the bilayer remained stable. Neither the interdiffusion of Cu and Si through the bilayer nor the silicide formation was identified, indicating the high diffusion resistance of the bilayer structure.