Method of barrier layer surface treatment to enable direct copper plating on barrier metal

Abstract

The invention discloses embodiments of a method of barrier layer surface treatment to enable direct copper plating without copper seed layer. In one embodiment, a method of plating copper on a substrate with a group VIII metal layer on top comprises pre-treating the substrate surface by removing a group VIII metal surface oxide layer and/or surface contaminants and plating copper on the pre-treated group VIII metal surface. Pre-treating the substrate can be accomplished by annealing the substrate in an environment with a hydrogen-containing gas environment and/or a non-reactive gas(es) to group VIII, by a cathodic treatment in an acid-containing bath, or by immersing the substrate in an acid-containing bath.

Description

technical field [0001] Embodiments of the invention generally relate to methods of barrier surface treatment that enable direct copper plating on barrier metals. Background technique [0002] Sub-quarter-micron, multilayer metallization is one of the key technologies for next-generation very large-scale integration (VLSI) and very large-scale integration (ULSI) semiconductor devices. The multilayer interconnects at the heart of this technology require filling contacts, vias, lines, and other features formed in voids with high aspect ratios. Reliable formation of these features is very important to the success of both VLSI and ULSI, as well as to the ongoing effort to increase circuit density and quality on individual substrates and dies. [0003] As circuit density increases, the widths of contacts, vias, lines, other features, and intervening dielectric material decrease to less than 65 nm, while the thickness of the dielectric layer remains substantially constant, resulti...

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Problems solved by technology

However, as feature sizes get smaller, it is difficult to have proper seed phase coverage with PVD techniques ...

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