US Patent 9721891 Integrated circuit devices and methods

An integrated circuit device includes a first metal layer including aluminum. The integrated circuit device includes a second metal layer including an interconnect structure. The interconnect structure includes a layer of first material including aluminum. The integrated circuit device includes an inter-diffusion layer that includes aluminum. The inter-diffusion layer is proximate to the first metal layer and proximate to the layer of first material including aluminum. The integrated circuit device includes an aluminum oxide barrier layer. The aluminum oxide barrier layer is proximate to a dielectric layer and proximate to the layer of first material including aluminum.