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US 11,866,831 B2Granted
Methods for wet atomic layer etching of copper
AssigneeTokyo Electron Limited
InventorsChristopher Netzband, Paul Abel, Jacques Faguet, Arkalgud Sitaram
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Abstract
The present disclosure provides a new wet atomic layer etch (ALE) process for etching copper. More specifically, the present disclosure provides various embodiments of methods that utilize new etch chemistries for etching copper in a wet ALE process. By utilizing the new etch chemistries disclosed herein within a wet ALE process, the present disclosure provides a highly selective etch of copper with monolayer precision.
Claims22
A method of etching, the method comprising:
- receiving a substrate having a copper metal layer formed thereon, wherein an oxidized copper surface layer of the copper metal layer is exposed on a surface of the substrate;
- exposing the surface of the substrate to a complexation solution comprising a carboxylic acid dissolved in an organic solvent, wherein the carboxylic acid reacts with the oxidized copper surface layer to form a copper carboxylate layer, which is insoluble within the organic solvent;
- removing the complexation solution from the surface of the substrate subsequent to forming the copper carboxylate layer;
- exposing the surface of the substrate to a dissolution solution to selectively remove the copper carboxylate layer and expose the copper metal layer underlying the copper carboxylate layer, wherein the dissolution solution comprises a reactive agent and an aqueous solvent, and wherein the reactive agent reacts with the copper carboxylate layer to form soluble species that are dissolved by the aqueous solvent;
- and
- removing the dissolution solution and the soluble species from the surface of the substrate to etch the copper metal layer.
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A method of etching copper using a wet atomic layer etching (ALE) process, the method comprising:
- a) receiving a substrate having a copper (Cu) metal layer with an oxidized Cu surface layer formed thereon;
- b) exposing the oxidized Cu surface layer to a complexation solution comprising a complexing agent to bind the complexing agent to the oxidized Cu surface layer and form a complex-bound oxidized Cu surface layer on the Cu metal layer;
- c) rinsing the substrate with a first purge solution to remove the complexation solution from a surface of the substrate;
- d) selectively removing the complex-bound oxidized Cu surface layer from the Cu metal layer by exposing the complex-bound oxidized Cu surface layer to a dissolution solution that dissolves the complex-bound oxidized Cu surface layer and forms a new oxidized Cu surface layer on the Cu metal layer;
- and
- e) rinsing the substrate with a second purge solution to remove the dissolution solution from the surface of the substrate and etch the Cu metal layer.
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Dependencies are inferred from the claim text.