Plasma source having a dielectric plasma chamber with improved plasma resistance
A plasma chamber of a plasma processing system is provided. The plasma chamber defines a plasma channel having a first side and a second side oppositely disposed along a length of the plasma channel. The plasma chamber comprises a first section and a second section constructed from a dielectric material and an interface that bonds together the first and second sections at between a first flange of the first section and a third flange of the second section and between a second flange of the first section and a fourth flange of the second section.
1. A plasma processing system comprising:
a plasma assembly including:
a plasma chamber defining a plasma channel having an inner side and an outer side oppositely disposed along a length of the channel, the plasma chamber comprising (i) two dielectric sections constructed from a dielectric material and (ii) a bonding interface that bonds together the two dielectric sections along a bonding plane to form a hermetic seal between the two sections, wherein the bonding interface includes a first bonded flange extending inward from the inner side along the bonding plane and a second bonded flange extending outward from the outer side along the bonding plane; and
a heat sink surrounding the plasma chamber, the heat sink being divided into two conductive segments along the bonding plane, wherein the two conductive segments are constructed from a conductive material and are electrically separated from each other; and
a power transformer including a magnetic core, a primary coil, and the plasma assembly, the power transformer configured to induce an electric field that ionizes a gas in the plasma chamber of the plasma chamber.
2. The plasma processing system of claim 1 , wherein the plasma assembly further comprises a thermal interface disposed between the heat sink and the plasma chamber, the thermal interface configured to provide at least one of accommodating thermally-induced deformation of the plasma chamber or conducting heat away from the plasma chamber toward the heat sink.
3. The plasma processing system of claim 2 , wherein the thermal interface is constructed from a compliant, thermally-conductive material.
4. The plasma processing system of claim 1 , wherein
the second bonded flange is configured to extend outward from the outer side of the plasma chamber parallel to the bonding plane, and
wherein the first bonded flange is configured to extend inward from the inner side of the plasma chamber parallel to the bonding plane.
5. The plasma processing system of claim 4 , wherein the plasma assembly further comprises one or more dielectric breaks located along at least one of the second bonded flange or the first bonded flange of the plasma chamber at the bonding interface.
6. The plasma processing system of claim 5 , wherein the two conductive segments of the heat sink are electrically separated by the one or more electric breaks and at least one of the second or first bonded flanges at the bonding interface.
7. The plasma processing system of claim 1 , wherein the plasma assembly further comprises one or more dielectric fluid couplings located in the plasma assembly, the dielectric fluid couplings in fluid communication with the conductive segments of the heat sink for conducting a cooling fluid between the conductive segments.
8. The plasma processing system of claim 1 , further comprising a supporting structure configured to support and cool the magnetic core of the power transformer.
9. The plasma processing system of claim 1 , wherein the bonding interface comprises a bonding agent that is one of a glass frit, a eutectic mixture or an epoxy.
10. The plasm processing system of claim 1 , wherein a first of the dielectric sections of plasma chamber and a first of the conductive segments of heat sink are located in a first half of the transformer relative to the bonding plane, and a second of the dielectric sections of plasma chamber and a second of the conductive segments of heat sink are located in a second half of the transformer relative to the bonding plane.
11. The plasma processing system of claim 10 , wherein the first and second dielectric sections of the plasma chamber are identical, and the first and second conductive segments of the heat sink are identical.
12. A method for operating a plasma processing system, the method comprising:
providing the plasma processing system including a power transformer having at least one magnetic core, a primary coil, and a plasma assembly, wherein the plasma assembly includes (i) a plasma chamber defining a plasma channel having an inner side and an outer side oppositely disposed along a length of the channel, the plasma chamber created by two dielectric sections bonded together to form a bonding interface along a bonding plane, the bonding interface includes a first bonded flange extending inward from the inner side along the bonding plane and a second bonded flange extending outward from the outer side along the bonding plane and (ii) a heat sink surrounding the plasma chamber, the heat sink being divided into two conductive segments along the bonding plane and electrically separated from each other;
supplying a gas to the plasma channel via a gas inlet;
inducing, by the power transformer, an electric field that ionizes the gas in the plasma channel of the plasma chamber to form a plasma therein; and
delivering at least a portion of the plasma out of the plasma channel via an exit flange.
13. The method of claim 12 , further comprising biasing the two conductive segments of the heat sink at opposite voltages to ignite the gas in the plasma channel prior to inducing the electric field in the plasma channel.
14. The method of claim 12 , further comprising electrically isolating the two conductive segments at the bonding interface by one or more electric breakers and at least one of the first bonded flange or the second bonded flange of the plasma chamber.
15. The method of claim 14 , wherein the second bonded flange extends outward from the outer side of the plasma chamber parallel to the bonding plane, and (ii) the first bonded flange extends inward from the inner side of the plasma chamber parallel to the bonding plane.
16. The method of claim 15 , further comprising increasing an amount of contact surface between the plasm chamber and the heat sink by the first and second bonded flanges of the plasma chamber, thereby decreasing a peak temperature in the plasma chamber.
17. The method of claim 15 , further comprising stiffening the plasma chamber within the power transformer by the first and second bonded flanges of the plasma chamber, thereby reducing deformation and thermal stress of the plasma chamber.
18. The method of claim 12 , further comprising cooling the heat sink by conducting a cooling fluid through a plurality of dielectric fluid couplings that are in fluid communication with the two conductive segments of the heat sink.
19. The method of claim 12 , further comprising reducing thermally-induced deformation of the plasma chamber by a thermal interface located between the plasma chamber and the heat sink.
20. The method of claim 19 , wherein the thermal interface is further configured to conduct heat away from the plasma chamber toward the heat sink.
21. The method of claim 12 , further comprising operating the plasma processing system as a remoted plasma source in a pulsed operation.