US 12,604,691 B2 · Methods for wet atomic layer etching of molybdenum in aqueous solution

Abstract

Methods are provided for etching molybdenum in a wet ALE process. The methods disclosed herein use a wide variety of techniques and wet etch chemistries to oxidize a molybdenum surface and form a self-limiting, molybdenum oxide passivation layer in a surface modification step of the wet ALE process. In the wet ALE processes and methods disclosed herein, self-limiting behavior is provided in the oxidation step by adding a polydentate ligand to an aqueous oxidizing solution. The polydentate ligand reacts with and binds to the oxidized molybdenum surface to form a stable, ligand-molybdenum oxide complex, which is insoluble within the aqueous oxidizing solution. The insolubility of the ligand-molybdenum complex in the aqueous oxidizing solution provides self-limiting behavior in the oxidation step. After forming the molybdenum oxide passivation layer, the passivation layer is selectively removed in a dissolution step of the wet ALE process to etch the molybdenum surface.

Claims24

Dependent claims

A method of etching, the method comprising:

receiving a substrate having a molybdenum (Mo) layer formed thereon, wherein a molybdenum surface is exposed on a surface of the substrate;
exposing the surface of the substrate to a surface modification solution comprising an oxidizer and a polydentate ligand dissolved in an aqueous solvent, wherein the oxidizer reacts with the molybdenum surface to oxidize the molybdenum surface and form a molybdenum oxide passivation layer, and wherein the polydentate ligand binds to the molybdenum oxide passivation layer to form a surface species that is insoluble in the aqueous solvent;
removing the surface modification solution from the surface of the substrate subsequent to forming the molybdenum oxide passivation layer;
exposing the surface of the substrate to a dissolution solution to selectively remove the molybdenum oxide passivation layer, wherein the dissolution solution reacts with the molybdenum oxide passivation layer to form soluble species that are dissolved by the dissolution solution;
and
removing the dissolution solution and the soluble species from the surface of the substrate to etch the molybdenum layer.

3 more elements

Dependencies are inferred from the claim text.

Methods for wet atomic layer etching of molybdenum in aqueous solution

Life of this patent

Methods for wet atomic layer etching of molybdenum in aqueous solution

Life of this patent

Abstract

Claims24