Methods of Producing Plasma in a Container

• US 20080156631A1
• Filed: 12/27/2006
• Published: 07/03/2008
• Est. Priority Date: 12/27/2006
• Status: Abandoned Application

• Current Assignee: Novellus Systems Incorporated (LAM Research Corporation)
• Original Assignee: Novellus Systems Incorporated (LAM Research Corporation)
• Inventors: Cheung, David, Fair, James A., Keller, John, Guha, Anirban, Jagusch, Peter, Decaux, Vincent
• Application Number:
  US11/616,326
• Publication Number:
  US 20080156631A1
• Time in Patent Office: Days
• US Class Current: 204/164
• CPC Class Codes: H01J 37/32357 Generation remote from the workpiece, e.g. down-stream
• CPC Class Codes: H01J 37/32458 Vessel
• CPC Class Codes: H05H 1/46 using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/26 takes precedence

Abstract

Methods of using a plasma generator to ash a work piece is provided. In an exemplary embodiment, the method includes flowing gas that has a gaseous component able to form plasma under conditions of radio-frequency energy excitation into the container. A proportion of the gas is directed to a first region of the container to form a higher gas density in the first region of the container and a corresponding lower gas density in a second region of the container. Sufficient energy is applied to the gas in at least the first region to excite a proportion of the gaseous component able to form plasma.

Claims

1. A method for producing plasma in a container, the method comprising the steps of:

flowing gas into the container, the gas comprising a gaseous component able to form plasma under conditions of radio-frequency energy excitation;

directing a proportion of the gas to a first region of the container to form a higher gas density in the first region of the container and a corresponding lower gas density in a second region of the container; and

applying sufficient energy to the gas in at least the first region to excite a proportion of the gaseous component able to form plasma to a plasma state.

2. The method of claim 1, wherein the step of directing comprises directing the gas using a nozzle.

3. The method of claim 2, wherein the step of directing comprises directing the gas through a plurality of gas outlets of a nozzle, the gas outlets aligned to direct gas to the first region.

4. The method of claim 1, wherein the step of directing comprises diverting gas into the first region using a baffle in a path of flow of the gas.

5. The method of claim 1, wherein the step of directing gas into the first region comprises directing the gas into a region that is subject to a greater amount of energy input during the step of applying energy than the second region.

6. The method of claim 1, wherein the step of directing gas into the first region comprises directing gas comprising air.

7. The method of claim 1, wherein the step of flowing gas comprising a gaseous component able to form plasma comprises flowing gas selected from the group consisting of oxygen, nitrogen, helium, hydrogen, fluorine, and fluorocarbons.

8. The method of claim 1, further comprising at least partially shielding walls of the container with a Faraday shield interposed between a source applying the energy and walls of the container.

9. The method of claim 8, further comprising flowing gas and plasma exiting from the container over a surface of a work piece and plasma ashing the surface of the work piece.

10. A method for producing plasma in a container and applying produced plasma to conduct ashing of a work piece, the method comprising the steps of:

flowing gas into a container comprising walls of a dielectric material, the gas comprising a gaseous component able to form plasma when subjected to appropriate excitation energy;

directing a proportion of the gas to a first region of the container to form a higher gas density in the first region of the container, the first region of the container comprising a region closest to an external source of excitation energy into the container;

applying sufficient excitation energy by means of the external source of excitation energy to gas in at least the first region to excite a proportion of the gaseous component able to form plasma to a plasma state; and

directing the formed plasma onto a surface of a work piece.

11. The method of claim 10, wherein the step of directing comprises directing the gas through a plurality of gas outlets of a nozzle, the gas outlets aligned to direct gas to the first region.

12. The method of claim 10, wherein the step of directing comprises diverting gas into the first region using a baffle in a path of flow of the gas.

13. The method of claim 10, further comprising the step of directing flowing gas and formed plasma through a gas distributor prior to the step of directing the formed plasma onto a surface of a work piece.

14. The method of claim 10, wherein the step of applying sufficient energy via the external source of excitation energy comprises applying sufficient energy to at least the first region via a coil energized by a radio frequency generator.

15. The method of claim 14, wherein the step of applying sufficient energy via the external source of excitation energy comprises applying sufficient energy to at least the first region via a symmetrically driven coil.

16. A method for producing plasma in a container and applying produced plasma to conduct ashing of a work piece, the method comprising the steps of:

flowing gas into a container comprising walls of quartz, the gas comprising a gaseous component able to form plasma when subjected to appropriate excitation energy;

directing a major proportion of the gas to a first region of the container to form a higher gas density in the first region of the container, the first region of the container comprising a region closest to an external source of excitation energy comprising a symmetrical coil into the container;

applying sufficient excitation energy by means of the symmetrical coil to gas in at least the first region of the container to excite a proportion of the gaseous component able to form plasma to a plasma state; and

directing the formed plasma onto a surface of a work piece.

17. The method of claim 16, wherein the step of directing comprises directing the gas through a plurality of gas outlets of a nozzle, the gas outlets aligned to direct gas to the first region.

18. The method of claim 16, wherein the step of directing comprises diverting gas into the first region using a baffle in a path of flow of the gas.

19. The method of claim 16, further comprising the step of directing flowing gas and formed plasma through a gas distributor prior to the step of directing the formed plasma onto a surface of a work piece.

20. The method of claim 16, wherein the step of flowing gas comprising a gaseous component able to form plasma comprises flowing gas selected from the group consisting of oxygen, nitrogen, helium, hydrogen, fluorine, and fluorocarbons.