Methods and apparatus for downstream dissociation of gases

• US 20060118240A1
• Filed: 12/03/2004
• Published: 06/08/2006
• Est. Priority Date: 12/03/2004
• Status: Abandoned Application

• Current Assignee: MKS Instruments Incorporated
• Original Assignee: Applied Science and Technology, Inc. (MKS Instruments Incorporated)
• Inventors: Chen, Xing, Holber, William M.
• Application Number:
  US11/003,109
• Publication Number:
  US 20060118240A1
• Time in Patent Office: Days
• US Class Current: 156/345.290
• CPC Class Codes: B01J 19/088 giving rise to electric discharges for heating purposes H05B7/00; for the production of ozone C01B13/11, H01T19/00
• CPC Class Codes: B01J 2219/0875 Gas
• CPC Class Codes: C23C 16/452 by activating reactive gas streams before their introduction into the reaction chamber, e.g. by ionisation or addition of reactive species
• CPC Class Codes: H01J 37/32357 Generation remote from the workpiece, e.g. down-stream
• CPC Class Codes: H01J 37/3244 Gas supply means

Abstract

A method and apparatus for activating and dissociating gases involves generating an activated gas with a plasma located in a chamber. A downstream gas input is positioned relative to an output of the chamber to enable the activated gas to facilitate dissociation of a downstream gas introduced by the gas input, wherein the dissociated downstream gas does not substantially interact with an interior surface of the chamber.

Claims

1. A method for dissociating gases comprising;

generating an activated gas with a plasma in a chamber; and

positioning a downstream gas input relative to an output of the chamber to enable the activated gas to facilitate dissociation of a downstream gas introduced by the gas input, wherein the dissociated downstream gas does not substantially interact with an interior surface of the chamber.

2. The method of claim 1 wherein the plasma is generated by a remote plasma source.

3. The method of claim 2 wherein the remote plasma source is a remote plasma source selected from the group consisting of an RF plasma generator, a microwave plasma generator, and a DC plasma generator.

4. The method of claim 1 wherein the plasma is generated from a plasma gas selected from the group consisting of oxygen, nitrogen and argon.

5. The method of claim 1 wherein the downstream gas comprises a halogen gas.

6. The method of claim 5 wherein the downstream gas comprises a halogen gas selected from the group consisting of F₂, XeF₂, NF₃, CF₄, CHF₃, C₂F₆, C₂HF₅, C₃F₈ and C₄F₈.

7. The method of claim 1 wherein the downstream gas comprises fluorine.

8. The method of claim 1 wherein an interior surface of the chamber comprises a material selected from the group consisting of quartz and sapphire.

9. The method of claim 1 wherein the downstream gas is introduced at a location relative to the output of the chamber that minimizes the interaction between the dissociated downstream gas and the interior surface of the chamber.

10. The method of claim 1 wherein the downstream gas is introduced at a location relative to the output of the chamber that maximizes the degree to which the downstream gas is dissociated.

11. The method of claim 1 wherein the downstream gas is introduced at a location relative to the output of the chamber that balances the degree to which the dissociated downstream gas interacts with the interior surface of the chamber with the degree to which the downstream gas is dissociated.

12. The method of claim 1 wherein the dissociated downstream gas is used to facilitate etching of a substrate.

13. The method of claim 1 comprising specifying a property of the downstream gas to optimize dissociation of the downstream gas.

14. The method of claim 13 wherein the property is one or more of pressure, flow rate and distance injected from the output of the chamber.

15. The method of claim 4 comprising specifying a property of the plasma gas to optimize dissociation of the downstream gas.

16. The method of claim 15 wherein the property is one or more of pressure, flow rate, gas type, gas composition and power to plasma.

17. The method of claim 1 wherein the downstream gas comprises a deposition material which is deposited on a semiconductor wafer located in a process chamber coupled to the chamber.

18. A method for dissociating gases comprising,

generating an activated gas from a plasma in a chamber;

and

introducing a downstream gas into the activated gas external to the chamber at a location sufficiently close to an output of the chamber such that the activated gas has an energy level sufficient to facilitate dissociation of the downstream gas, wherein the location is sufficiently spaced from the output of the chamber such that the dissociated downstream gas does not substantially interact with an interior surface of the chamber.

19. A method for etching a photoresist comprising;

generating an activated gas with a plasma in a chamber;

combining a downstream gas with at least a portion of the activated gas such that,

i) the activated gas comprises an energy level sufficient to facilitate dissociation of the downstream gas, and

ii) the dissociated downstream gas does not substantially interact with an interior surface of the chamber; and

etching a substrate with the dissociated downstream gas.

20. A method for dissociating gases comprising;

generating an activated gas with a plasma in a chamber; and

introducing a downstream gas to interact with the activated gas outside a region defined by the plasma to enable the activated gas to facilitate dissociation of the downstream gas, wherein the dissociated gas does not substantially interact with an interior surface of the chamber.

21. A system for dissociating gases comprising;

a plasma source for generating a plasma in a chamber, wherein the plasma generates an activated gas; and

means for combining at least a portion of the activated gas with a downstream gas to enable the activated gas to facilitate dissociation of the downstream gas, wherein the dissociated downstream gas does not substantially interact with an interior surface of the chamber.

22. A system for dissociating gases comprising;

a remote plasma source for generating a plasma region in a chamber, wherein the plasma generates an activated gas; and

an injection source for introducing a downstream gas to interact with the activated gas outside the plasma region, wherein the activated gas facilitates dissociation of the downstream gas, and wherein the dissociated downstream gas does not substantially interact with an interior surface of the chamber.

23. The system of claim 22, comprising a barrier located at an output of the chamber to reduce erosion of the chamber.

24. The system of claim 23 wherein the barrier is located at least partially within the chamber.

25. The system of claim 23 wherein the barrier is located at least partially within an output passage of the chamber.

26. The system of claim 22, comprising a barrier located within an output passage of the chamber.

27. The system of claim 22 wherein the chamber comprises quartz.

28. The system of claim 27 wherein the chamber is a toroidal-shaped chamber.

29. The system of claim 22 wherein the plasma source is a toroidal plasma source.