Inductively-coupled torodial plasma source

• US 7,166,816 B1
• Filed: 05/03/2004
• Issued: 01/23/2007
• Est. Priority Date: 06/26/1997
• Status: Expired due to Fees

• Current Assignee: MKS Instruments Incorporated
• Original Assignee: MKS Instruments Incorporated
• Inventors: Chen, Xing, Holber, William M., Georgelis, Eric, Cowe, Andrew Barnett, Bystyak, Ilya M., Bortkiewicz, Andrzej
• Primary Examiner(s): Paschall; Mark
• Application Number:
  US10/837,912
• Time in Patent Office: 995 Days
• Field of Search: 219/121.4, 219/121.41, 219/121.43, 219/121.54, 219/121.57, 118/723.R, 156/345.48
• US Class Current: 219/121.41
• CPC Class Codes: H05H 1/46 using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/26 takes precedence
• CPC Class Codes: H05H 1/4652 using inductive coupling means, e.g. coils
• CPC Class Codes: H05H 2242/22 DC, AC or pulsed generators

Abstract

Apparatus for dissociating gases includes a plasma chamber comprising a gas. A first transformer having a first magnetic core surrounds a first portion of the plasma chamber and has a first primary winding. A second transformer having a second magnetic core surrounds a second portion of the plasma chamber and has a second primary winding. A first solid state AC switching power supply including one or more switching semiconductor devices is coupled to a first voltage supply and has a first output that is coupled to the first primary winding. A second solid state AC switching power supply including one or more switching semiconductor devices is coupled to a second voltage supply and has a second output that is coupled to the second primary winding. The first solid state AC switching power supply drives a first AC current in the first primary winding. The second solid state AC switching power supply drives a second AC current in the second primary winding. The first AC current and the second AC current induce a combined AC potential inside the plasma chamber that directly forms a toroidal plasma that completes a secondary circuit of the transformer and that dissociates the gas.

Claims

1. An apparatus for dissociating gases, the apparatus comprising:

a toroidally-shaped plasma chamber for containing a gas, the plasma chamber comprising at least one dielectric spacer protected from a plasma in the chamber; and

a transformer to induce an electric field within the chamber, the transformer having a primary winding and a magnetic core surrounding a portion of the plasma chamber.

2. The apparatus of claim 1 wherein the at least one spacer separates mating surfaces of the chamber.

3. The apparatus of claim 1 wherein a chamber wall protrusion protects the at least one dielectric spacer.

4. The apparatus of claim 1 comprising at least one vacuum seal.

5. The apparatus of claim 4 wherein the at least one vacuum seal is located adjacent the at least one dielectric spacer.

6. The apparatus of claim 4 wherein the at least one vacuum seal is located outside the at least one dielectric spacer.

7. The apparatus of claim 1 wherein the at least one dielectric spacer is a plurality of spacers that separate mating surfaces of the chamber.

12. The apparatus of claim 1 wherein the at least one dielectric region is a plurality of regions that separate mating surfaces of the chamber.

8. An apparatus for dissociating gases, the apparatus comprising:

a toroidally-shaped plasma chamber for containing a gas, the plasma chamber comprising at least one dielectric region that breaks electrical continuity through the plasma chamber and is protected from a plasma in the plasma chamber; and

a transformer to induce an electric field within the chamber and dissociate the gas, the transformer having a primary winding and having a magnetic core surrounding a portion of the plasma chamber.

9. The apparatus of claim 8 wherein the at least one dielectric region comprises a spacer that separates mating surfaces of the chamber.

10. The apparatus of claim 9 wherein a chamber wall protrusion protects the spacer.

11. The apparatus of claim 8 comprising at least one vacuum seal.

13. An apparatus for dissociating gases, the apparatus comprising:

a toroidally-shaped plasma chamber for containing a gas, the plasma chamber comprising at least two electrically isolated regions separated by a dielectric region, said dielectric region protected from a plasma in the plasma chamber; and

a transformer to induce an electric field within the chamber and dissociate the gas, the transformer having a primary winding and having a magnetic core surrounding a portion of the plasma chamber.

14. The apparatus of claim 13 wherein the regions are joined with a vacuum seal.

15. The apparatus of claim 13 wherein the chamber comprises a plurality of dielectric spacers that separate mating surfaces of the chamber.

16. The apparatus of claim 15 wherein chamber wall protrusions protect the spacers.

17. An apparatus for dissociating gases, the apparatus comprising:

a toroidally-shaped plasma chamber for containing a gas, the plasma chamber comprising at least one dielectric spacer;

means for protecting the at least one spacer from a plasma in the chamber; and

a transformer to induce an electric field within the chamber, the transformer having a primary winding and having a magnetic core surrounding a portion of the plasma chamber.

18. The apparatus of claim 17 wherein chamber comprises a metal material.