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US 11,802,342 B2Granted
Methods for wet atomic layer etching of ruthenium
AssigneeTokyo Electron Limited
InventorPaul Abel
Life of this patent
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Abstract
The present disclosure provides a new wet atomic layer etch (ALE) process for etching ruthenium. More specifically, the present disclosure provides various embodiments of methods that utilize new etch chemistries for etching ruthenium in a wet ALE process. Unlike conventional etch processes for ruthenium, the wet ALE process described herein for etching ruthenium is metal-free, cost-effective and improves surface roughness during etching.
Claims24
A method of etching, the method comprising:
- receiving a substrate having ruthenium formed thereon, wherein a ruthenium surface is exposed on a surface of the substrate;
- exposing the surface of the substrate to a first etch solution such that the first etch solution is in contact with the ruthenium surface, wherein the first etch solution includes a halogenation agent dissolved in a first solvent, and wherein the halogenation agent chemically modifies the ruthenium surface to form a halogenated ruthenium passivation layer on the ruthenium surface, wherein the halogenated ruthenium passivation layer is self-limited and insoluble to the first etch solution;
- removing the first etch solution from the surface of the substrate subsequent to forming the halogenated ruthenium passivation layer;
- exposing the surface of the substrate to a second etch solution including a reactive agent and a second solvent, wherein the reactive agent is a ligand species, which reacts with and binds to the halogenated ruthenium passivation layer to form soluble species that are dissolved by the second solvent;
- and
- removing the second etch solution and the soluble species from the substrate.
3 more elements
A method of etching, the method comprising:
- receiving a substrate having ruthenium formed thereon, wherein a ruthenium surface is exposed on a surface of the substrate;
- exposing the surface of the substrate to a first etch solution such that the first etch solution is in contact with the ruthenium surface, the first etch solution including one or more species that cause a passivation layer to be formed on the ruthenium surface, wherein the passivation layer is self-limited and insoluble to the first etch solution, and wherein the one or more species in the first etch solution include an oxidizer, a cation and a chlorine source reactive to the ruthenium;
- removing the first etch solution from the surface of the substrate subsequent to forming the passivation layer;
- exposing the surface of the substrate to a second etch solution including a reactive agent and a solvent, the reactive agent reacting with the passivation layer and forming soluble species that are dissolved by the solvent;
- and
- removing the second etch solution and the soluble species from the substrate.
3 more elements
A method of etching a substrate using a wet atomic layer etching (ALE) process, the method comprising:
- a) receiving the substrate, the substrate having a ruthenium (Ru) layer thereon;
- b) exposing the Ru layer to a first etch solution containing a halogenating agent to form a chemically modified Ru surface layer containing a ruthenium halide or a ruthenium oxyhalide;
- c) rinsing the substrate with a first purge solution to remove the first etch solution from a surface of the substrate;
- d) exposing the chemically modified Ru surface layer to a second etch solution to dissolve the chemically modified Ru surface layer, wherein the second etch solution includes a ligand dissolved in a second solvent, wherein the ligand reacts with and binds to the chemically modified Ru surface layer to form a soluble species that dissolves within the second solvent;
- e) rinsing the substrate with a second purge solution to remove the second etch solution from the surface of the substrate;
- and
- f) repeating steps b)-e) for one or more cycles.
4 more elements
A method of etching a substrate using a wet atomic layer etching (ALE) process, the method comprising:
- a) receiving the substrate, the substrate having a ruthenium (Ru) layer thereon;
- b) exposing the Ru layer to a first etch solution containing an oxidizer, a cation and a chlorine source reactive to the Ru layer to form a chemically modified Ru surface layer containing a ruthenium salt;
- c) rinsing the substrate with a first purge solution to remove the first etch solution from a surface of the substrate;
- d) exposing the chemically modified Ru surface layer to a second etch solution to dissolve the chemically modified Ru surface layer;
- e) rinsing the substrate with a second purge solution to remove the second etch solution from the surface of the substrate;
- and
- f) repeating steps b)-e) for one or more cycles.
4 more elements
Dependencies are inferred from the claim text.