Methods For Selective Removal Of Surface Oxides On Metal Films

A method for removing a native oxide formed on a surface of a metal film, the method comprising:

• receiving a substrate having the metal film exposed on a surface of the substrate, wherein the native oxide is formed on the surface of the metal film;
• exposing the surface of the substrate to an oxidizing agent to further oxidize the native oxide and form a metal oxide surface layer or a metal hydroxide surface layer;
• exposing the surface of the substrate to a dissolution solution comprising a ligand dissolved in a non-aqueous solvent, wherein the ligand reacts with and binds to the metal oxide surface layer or the metal hydroxide surface layer to form a ligand-metal complex, which is soluble within and selectively dissolved by the non-aqueous solvent;
• and
• rinsing the substrate to remove the dissolution solution and the ligand-metal complex from the surface of the substrate;
• wherein said exposing the surface of the substrate to the oxidizing agent, said exposing the surface of the substrate to the dissolution solution and said rinsing the substrate selectively remove the native oxide formed on the surface of the metal film without removing the metal film.

A method for stripping a native oxide from a cobalt metal film, the method comprising:

• receiving a substrate having the cobalt metal film exposed on a surface of the substrate, wherein the native oxide is formed on the cobalt metal film;
• exposing the surface of the substrate to a dissolution solution comprising a ligand dissolved in a non-aqueous solvent, wherein the ligand reacts with and binds to the native oxide to form a ligand-metal complex, which is self-limiting and selectively dissolved with the non-aqueous solvent;
• and
• rinsing the substrate to remove the dissolution solution and the ligand-metal complex from the surface of the substrate;
• wherein said exposing the surface of the substrate to the dissolution solution and said rinsing the substrate strips the native oxide from the cobalt metal film without removing the cobalt metal film.