Externally excited torroidal plasma source

A plasma reactor for processing a workpiece, said plasma reactor comprising:

• an enclosure;
• a workpiece support within the enclosure, said workpiece support and the overlying portion of said enclosure defining a process region therbetween extending generally across the diameter of said workpiece support;
• said enclosure having at least first and second openings therethrough near generally opposite sides of said workpiece support;
• at least one hollow conduit outside of said process region and connected to said first and second opening, providing a first torroidal path extending through said conduit and across said process region;
• a first coil antenna adapted to accept RF power, and inductively coupled to the interior of said hollow conduit and capable of maintaining a plasma in said torroidal path;
• and
• wherein said conduit is formed of a metal material, said conduit having an insulating gap within a wall of the conduit extending transversely to said torriodal path and separating said conduit into two portions so as to prevent formation of a closed electrical path along the lenght of said conduit.

A plasma reactor for processing a workpiece, said plasma reactor comprising:

• an enclosure;
• a workpiece support within the enclosure facing an overlying portion of the enclosure, said workpiece support and the overlying portion of said enclosure defining a process region therebetween extending generally across the diameter of said workpiece support;
• said enclosure having at least first and second openings therethrough near generally opposite sides of said workpiece support;
• at least one hollow conduit outside of said process region and connected to said first and second openings, providing a first torroidal path extending through said conduit and across said process region;
• a first coil antenna adapted to accept RF power, and inductively coupled to the interior of said hollow conduit and capable of maintaining a plasma in said torroidal path;
• wherein said coil antennais wound around an axis generally parallel with the axis of said closed torroidal path;
• wherein said coil antenna comprises a first winding extending on one side of and along said conduit;
• and
• wherein said coil antenna comprises a second winding extending on an opposite side of and along said conduit.

A plasma reactor for processing a workpiece, said plasma reactor comprising:

• an enclosure;
• a workpiece support within the enclosure facing an portion of the enclosure, said workpiece support and the overlying portion of said enclosure defining a process region therebetween extending generally across the diameter of said workpiece support;
• said enclosure having at least first and second openings therethrough near generally opposite sides of said workpiece support;
• at least one hollow conduit outside of said process region and connected to said first and second openings, providing a first torroidal path extending through said conduit and across said process region;
• a first coil antenna adapted to accept RF power, and inductively coupled to the interior of said hollow conduit and capable of maintaining a plasma in said torroidal path;
• and
• wherein the height of said closed torroidal path along an axis generally perpendicular to a plane of said wafer support in a process region overlying said workpiece support is less than elsewhere in said closed torroidal path, whereby to enhance the plasma ion density in said process region relative to the plasma ion density elsewhere in said closed torroidal path.