INVERTED PLASMA SOURCE, AND METHOD
A plasma source is configured to be in fluid communication with the interior of a vacuum vessel, a vacuum chamber, such as by being installed in a wall of a vacuum vessel that encloses the chamber, or in a pipe that is connected to the chamber. The plasma source may produce plasma in a line of sight of a surface to be cleaned, such as an internal surface of the vessel, which may be used for processes such as deposition or etching.
1 . A plasma source comprising:
a plasma source body, wherein the plasma source body includes a dielectric material;
a ferrite core within the plasma source body;
an electrode within the plasma source body;
wherein the plasma source body is configured to generate a plasma when the ferrite core is energized, with the plasma generated forming at least partially external to the plasma source body, around the ferrite core, the electrode, and the dielectric material; and
a mount mechanically coupled to plasma source body, for coupling the plasma source body to a vacuum vessel with the plasma source body in fluid communication with an interior of the vacuum vessel.
2 . The plasma source of claim 1 , wherein at least 50% of a length of the plasma is external to the plasma source body.
3 . The plasma source of claim 1 ,
wherein the plasma source body defines an inner bore; and
wherein a plasma location, where the plasma forms when the ferrite core is energized, passes through the inner bore.
4 . The plasma source of claim 3 , wherein the inner bore is part of a through-hole that also passes through the ferrite core, the electrode, and the dielectric material.
5 . The plasma source of claim 1 , wherein the ferrite core is toroidal.
6 . The plasma source of claim 1 , wherein the electrode is a capacitively coupled plasma (CCP) electrode.
7 . The plasma source of claim 1 , wherein the electrode is mounted on the dielectric material.
8 . The plasma source of claim 1 , wherein the dielectric material is a dielectric plate.
9 . The plasma source of claim 1 , wherein the dielectric material is a dielectric material ring.
10 . The plasma source of claim 1 , further comprising one or more windings around the ferrite core.
11 . The plasma source of claim 1 , wherein the mount includes a flange.
12 . The plasma source of claim 1 , wherein the mount includes a re-entrant adapter configured to pass through a port in a wall of the vacuum vessel.
13 . The plasma source of claim 1 , further comprising a gas fitting coupled to the flange, for passing gas through the plasma into fluid communication with the interior of the vacuum vessel.
14 . The plasma source of claim 1 , wherein the plasma source includes a gas feed to direct gas to a plasma location, where the plasma forms when the ferrite core is energized.
15 . The plasma source of claim 14 , wherein the gas feed includes gas channels in the plasma source body.
16 . The plasma source of claim 15 , wherein the gas channels direct the gas feed radially inward to an inner bore defined by the plasma source body.
17 . The plasma source of claim 1 , in combination with the vacuum vessel.
18 . A plasma source comprising:
a plasma source body, wherein the plasma source body includes a dielectric material;
a ferrite core within the plasma source body;
an electrode within the plasma source body;
wherein the plasma source body is configured to generate a plasma at a plasma location when the ferrite core is energized, with the plasma generated forming at least partially external to the plasma source body, around the ferrite core, the electrode, and the dielectric material; and
wherein the plasma source body includes a reduced-thickness region that defines the plasma location at a shortest-loop location.
19 . A plasma source comprising:
a plasma source body, wherein the plasma source body includes a dielectric material;
a ferrite core within the plasma source body;
an electrode within the plasma source body;
wherein the plasma source body is configured to generate a plasma at a plasma location when the ferrite core is energized, with the plasma generated forming at least partially external to the plasma source body, around the ferrite core, the electrode, and the dielectric material;
wherein the plasma source body defines an inner bore;
wherein the plasma location passes through the inner bore;
wherein the plasma source includes a gas feed to direct gas to the plasma location; and
wherein the gas feed includes gas channels that direct the gas feed radially inward to an inner bore defined by the plasma source body.
20 . A method of cleaning an interior surface of a vacuum chamber, the method comprising:
placing a plasma source as described in claim 1 in fluid communication with an interior of the vacuum chamber;
energizing cleaning gas by passing the cleaning gas through a plasma created by the plasma source to produce energized cleaning gas; and
thereafter cleaning the interior surface of the vacuum chamber with the energized cleaning gas.