Low-resistivity metallic interconnect structures with self-forming diffusion barrier layers

Abstract

Methods for fabricating low-resistivity metallic interconnect structures with self-forming diffusion barrier layers are provided, as well as semiconductor devices comprising low-resistivity metallic interconnect structures with self-formed diffusion barrier layers. For example, a semiconductor device includes a dielectric layer disposed on a substrate, an opening etched in the dielectric layer, ametallic liner layer covering sidewall and bottom surfaces of the opening in the dielectric layer, a copper material filling the opening to form an interconnect structure, and a self-formed diffusionbarrier layer formed in the sidewall surfaces of the opening of the dielectric layer. The self-formed diffusion barrier layer includes manganese atoms which are diffused into the sidewall surfaces ofthe dielectric layer.

Description

technical field [0001] The present invention relates generally to semiconductor fabrication techniques, and in particular, to techniques for fabricating metal interconnect structures. Background technique [0002] Semiconductor integrated circuit chips are typically fabricated with back-end-of-line (BEOL) interconnect structures that include multiple layers of metal lines and interlayer metal vias to connect portions that are front-end-of-line (FEOL) layers of the semiconductor integrated circuit chip Manufactured various integrated circuit components and devices. The current state of the art EOL process technology typically implements copper to form BEOL interconnects, since the use of copper material is known to significantly reduce electrical resistance in BEOL interconnect structures, resulting in improved conductivity and higher performance. However, as the copper interconnect structure is scaled down, the electrical resistivity and current density within the copper in...

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Problems solved by technology

However, the use of cobalt and ruthenium barrier / liner layers for copper interconnects can be problematic because such materials do not provide a level of adhesion to the dielectric material of the ILD layer that is as strong as conventional TaN or TiN barrier layers, and Therefore the interfacial adhesion between the cobalt or ruthenium liner layer and the dielectric material of the ILD layer is weak

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