Self-formed gradient Zr/ZrN double layer diffusion barrier layer and preparation method thereof

The invention provides a self-formed gradient Zr/ZrN double layer diffusion barrier layer and a preparation method thereof. A diffusion barrier layer comprises: a substrate, a Cu(Zr) alloy film which is deposited on the substrate and is taken as a seed layer and a self-precipitation layer, a nanocrystalline ZrN which is implanted between the substrate and the Cu(Zr) alloy film and is taken as a pre-barrier and a pure copper interconnection wire deposited on an upper layer of the Cu(Zr) alloy film. The double layer barrier layer formed in the invention is continuous, uniform and compact. A thickness can be controlled in several nanometers. A resistance is low, heat stability is high and adhesion is good. A performance requirement of a hyper-scale integrated circuit to the Cu interconnection diffusion barrier layer can be satisfied.