Low temperature carbon gapfill with reduced void or seam formation

A semiconductor processing method comprising:

• providing a carbon-containing precursor to a processing region of a semiconductor processing chamber, wherein a substrate is disposed within the processing region of the semiconductor processing chamber, and wherein the substrate defines one or more recessed features along the substrate;
• forming a plasma of the carbon-containing precursor within the processing region, wherein the plasma of the carbon-containing precursor is generated at a first plasma power;
• depositing a carbon-containing material on the substrate, wherein the carbon-containing material extends within the one or more recessed features along the substrate;
• halting a flow of the carbon-containing precursor;
• providing a hydrogen-containing precursor to the processing region of the semiconductor processing chamber;
• forming a plasma of the hydrogen-containing precursor within the processing region, wherein the plasma of the hydrogen-containing precursor is generated at a second plasma power, and wherein the second plasma power is greater than the first plasma power;
• and
• treating the carbon-containing material with effluents of a hydrogen-containing plasma, wherein effluents of the hydrogen-containing plasma cause a portion of the carbon-containing material to be removed from the substrate.

A semiconductor processing method comprising:

• providing a carbon-containing precursor to a processing region of a semiconductor processing chamber, wherein the carbon-containing precursor comprises acetylene, wherein a substrate is disposed within the processing region of the semiconductor processing chamber, and wherein the substrate defines one or more recessed features along the substrate;
• forming a plasma of the carbon-containing precursor within the processing region, wherein the plasma of the carbon-containing precursor is generated at a plasma power of less than or about 300 W;
• depositing a carbon-containing material on the substrate, wherein the carbon-containing material extends within the one or more recessed features along the substrate;
• halting a flow of the carbon-containing precursor;
• forming a plasma of a hydrogen-containing precursor within the processing region of the semiconductor processing chamber, wherein the hydrogen-containing precursor comprises diatomic hydrogen;
• and
• etching a portion of the carbon-containing material with plasma effluents of the hydrogen-containing precursor;
• wherein a temperature within the processing region is maintained at less than or about 500° C., and a pressure within the processing region is maintained at less than or about 3 Torr.