Methods for conditioning a surface prior to etching to optimize etch performance
AssigneeTokyo Electron Limited
InventorKate Abel
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Abstract
New methods are provided for conditioning a surface of a material to be etched prior to etching the material. More specifically, the present disclosure provides various embodiments of methods for conditioning a surface of a metal layer prior to etching the metal layer using etch chemistry optimized for the bulk metal layer. In some embodiments, the techniques disclosed herein may be used to condition a surface of a ruthenium (Ru) layer prior to etching the ruthenium layer using halogenating etch chemistries in a wet atomic layer etching (ALE) process.
Claims25
A method for conditioning a surface of a metal layer to be etched prior to etching the metal layer, the method comprising:
- receiving a substrate having the metal layer formed thereon, wherein a metal surface is exposed on a surface of the substrate;
- annealing the substrate in a reducing atmosphere to at least partially reduce the metal surface;
- exposing the substrate to a gas-phase L-type ligand to form a passivation layer on the metal surface;
- and
- etching the metal layer using a wet etch process, wherein the passivation layer formed on the metal surface increases an etch rate of the metal layer during the wet etch process, compared to an etch rate achieved without the passivation layer.
A method for conditioning a surface of a ruthenium (Ru) layer to be etched prior to etching the ruthenium layer, the method comprising:
- receiving a substrate having the ruthenium layer formed thereon, wherein a ruthenium surface is exposed on a surface of the substrate;
- annealing the substrate in a reducing atmosphere to at least partially reduce the ruthenium surface;
- exposing the substrate to a carbon monoxide (CO) gas to form a carbonyl passivation layer on the ruthenium surface;
- and
- etching the ruthenium layer using a wet etch process, wherein the carbonyl passivation layer formed on the ruthenium surface increases an etch rate of the ruthenium layer during the wet etch process, compared to an etch rate achieved without the carbonyl passivation layer.
A method for conditioning a surface of a ruthenium (Ru) layer to be etched prior to etching the ruthenium layer in a wet atomic layer etching (ALE) process, the method comprising:
- receiving a substrate having the ruthenium layer formed thereon, wherein a ruthenium surface is exposed on a surface of the substrate;
- annealing the substrate in a reducing atmosphere to at least partially reduce the ruthenium surface;
- exposing the substrate to a gas-phase L-type ligand to form a passivation layer on the ruthenium surface;
- and
- etching the ruthenium layer by performing multiple cycles of the wet ALE process, wherein each cycle comprises:
- exposing the ruthenium surface to a first etch solution comprising a chlorinating agent dissolved in a non-aqueous solvent to form a ruthenium chloride or oxychloride passivation layer, which is self-limiting and insoluble in the non-aqueous solvent;
- rinsing the substrate with a first purge solution to remove the first etch solution from the surface of the substrate;
- exposing the ruthenium chloride or oxychloride passivation layer to a second etch solution to selectively remove the ruthenium chloride or oxychloride passivation layer and expose an unmodified ruthenium surface underlying the ruthenium chloride or oxychloride passivation layer;
- and
- rinsing the substrate with a second purge solution to remove the second etch solution from the surface of the substrate and etch the ruthenium layer;
- wherein the passivation layer formed on the ruthenium surface increases an etch rate of the ruthenium layer during said etching, compared to an etch rate achieved without the passivation layer.
Dependencies are inferred from the claim text.