Cobalt-containing material removal

A method of etching cobalt from a substrate, the method comprising:

• placing the substrate into a first substrate processing region, wherein the substrate comprises cobalt and an overlying cobalt oxide;
• reducing the cobalt oxide and exposing the cobalt by flowing a hydrogen-containing precursor into a first substrate processing region housing the substrate while forming a hydrogen plasma in the substrate processing region;
• placing the substrate into a second substrate processing region;
• forming cobalt halide and amorphizing a portion of the cobalt by flowing a halogen-containing precursor into the second substrate processing region while forming a local plasma from the halogen-containing precursor to form halogen-containing plasma effluents, wherein forming the cobalt halide and amorphizing the portion of the cobalt further comprises accelerating the halogen-containing plasma effluents towards the substrate by biasing the plasma relative to the substrate;
• flowing a carbon-and-nitrogen-containing precursor into the second substrate processing region, wherein the second substrate processing region is plasma-free during the flowing of the carbon-and-nitrogen-containing precursor and flowing of the carbon-and-nitrogen-containing precursor occurs after flowing the halogen-containing precursor;
• removing cobalt from the substrate;
• and
• removing the substrate from the second substrate processing region.

A method of etching cobalt from a substrate, the method comprising:

• placing the substrate into a substrate processing region, wherein the substrate comprises exposed cobalt;
• forming cobalt halide and amorphizing a portion of the cobalt by flowing a halogen-containing precursor into the substrate processing region while forming a local plasma from the halogen-containing precursor to form halogen-containing plasma effluents, wherein forming the cobalt halide and amorphizing the portion of the cobalt further comprises accelerating the halogen-containing plasma effluents towards the substrate by biasing the plasma relative to the substrate, and wherein the cobalt halide is formed from cobalt from the substrate and halogen from the halogen-containing precursor;
• removing cobalt from the substrate by flowing a carbon-and-nitrogen-containing precursor into the (same) substrate processing region, wherein the substrate processing region is plasma-free during the flowing of the carbon-and-nitrogen-containing precursor and flowing of the carbon-and-nitrogen-containing precursor occurs after flowing the halogen-containing precursor;
• and
• removing the substrate from the substrate processing region.