Treatment of tungsten surface for tungsten gap-fill

A method of filling a feature formed on a substrate, comprising:

• depositing one or more tungsten-containing layers over a surface of a substrate, wherein
• the substrate comprises a plurality of features formed within a field region of the surface of the substrate,
• each of the plurality of features comprises a sidewall surface and a bottom surface, and
• the deposited one or more tungsten-containing layers are formed over the field region, sidewall surface, and bottom surface of the plurality of features;
• exposing the surface of the substrate to a gradient oxidizing process, wherein the gradient oxidizing process forms preferentially oxidized regions of the tungsten-containing layers that are disposed over the field region of the plurality of features;
• preferentially etching the preferentially oxidized regions of the deposited one or more tungsten-containing layers formed on the surface of the substrate, wherein, after performing the process of preferentially etching the preferentially oxidized regions, a first portion of the deposited one or more tungsten-containing layers remains on the bottom surface of each of the plurality of features and a second portion of the deposited one or more tungsten-containing layers remains on the sidewall surface of each of the plurality of features;
• exposing at least the second portion of the deposited one or more tungsten containing layers to a post-etch treatment process to reduce oxidized tungsten to tungsten and remove contaminants from surfaces of the deposited one or more tungsten-containing layers;
• and
• filling the features with a second tungsten layer, wherein the process of filling the features with the second tungsten layer comprises preferentially growing the second tungsten layer from the second portion of the deposited one or more tungsten-containing layers on the sidewall surface and the first portion of the deposited one or more tungsten-containing layers that remain on the bottom surface of each of the features.

A cluster tool, comprising:

• a first process chamber, comprising:
• an oxygen source that is fluidly coupled to a processing region of the first process chamber, wherein the oxygen source is configured to deliver an oxygen-containing gas to the processing region;
• a first flow control valve that is configured to control the flow of oxygen-containing gas provided from the oxygen source to the processing region;
• a hydrogen source that is fluidly coupled to the processing region of the first process chamber, wherein the hydrogen source is configured to deliver a hydrogen-containing gas to the processing region;
• a second flow control valve that is configured to control the flow of the hydrogen-containing gas provided from the hydrogen source to the processing region;
• an etching gas source that is fluidly coupled to the processing region of the first process chamber, wherein the etching gas source is configured to deliver an etching gas to the processing region;
• a third flow control valve that is configured to control the flow of the etching gas provided from the etching gas source to the processing region;
• and
• an inductively coupled plasma source that is configured to generate a plasma in the processing region, wherein the plasma comprises the hydrogen-containing gas and the oxygen-containing gas;
• and
• a controller that is configured to:
• control the first flow control valve so that an amount of oxygen-containing gas provided to a surface of a substrate, disposed in the processing region of the first processing chamber, to preferentially oxidize one or more tungsten-containing layers disposed on a field region and sidewalls of features formed in the substrate by generating the plasma in the processing region of first process chamber;
• control the third flow control valve so that an amount of etching gas provided to the surface of the substrate preferentially etches the preferentially oxidized portions of the one or more tungsten-containing layers disposed on the field region and sidewalls of features formed in the substrate to be performed in the first process chamber;
• and
• control the first flow control valve and the second flow control valve to deliver an amount of the oxygen-containing gas and the hydrogen-containing gas to the processing region to expose the one or more tungsten-containing layers to the post-etch treatment process comprises exposing the tungsten-containing layers to a hydrogen and oxygen plasma treatment process by generating an inductive coupled plasma comprising the oxygen-containing gas and the hydrogen-containing gas.