Porous ceramic liner for a plasma source

• US 6,367,412 B1
• Filed: 02/17/2000
• Issued: 04/09/2002
• Est. Priority Date: 02/17/2000
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Bhatnagar, Ashish, Moalem, Mehran, Ramaswamy, Kartik, Kaushal, Tony S., Wong, Kwok Manus, Shamouilian, Shamouil
• Primary Examiner(s): Mills, Gregory
• Assistant Examiner(s): HASSANZADEH, PARVIZ
• Application Number:
  US09/506,111
• Time in Patent Office: 782 Days
• Field of Search: 118/723.I, 118/723.ER, 118/723.ME, 118/723.IR, 118/723.DC, 118/723.MR, 118/715, 156/345, 552/86
• US Class Current: 118/723.00I
• CPC Class Codes: B01D 2257/2066 Fluorine
• CPC Class Codes: B01D 2259/818 Employing electrical discharges or the generation of a plasma
• CPC Class Codes: B01D 53/8662 Organic halogen compounds
• CPC Class Codes: C23C 16/4412 Details relating to the exhausts, e.g. pumps, filters, scrubbers, particle traps
• CPC Class Codes: H01J 37/32495 Means for protecting the vessel against plasma
• CPC Class Codes: Y02C 20/30 of perfluorocarbons [PFC], hydrofluorocarbons [HFC] or sulfur hexafluoride [SF6]

Abstract

A plasma tube comprising a vacuum sealing ceramic outer tube, a porous ceramic insert disposed on the inside wall of the outer tube, and a source of high frequency radiation, for example, an RF coil wrapped around the tube, to excite gas flowing through the bore of the insert into a plasma. The invention is particularly useful as an exhaust scrubber for oxidizing exhaust gases from a semiconductor processing chamber. A catalyst may be embedded in the porous insert to promote the scrubbing reaction. The invention may also be used in an applicator of a remote plasma source.

Claims

1. A plasma tube, comprising:

a vacuum sealing ceramic outer tube;

a porous ceramic inner tube formed from a material that is porous throughout and disposed and slidably fitted within said outer tube through a center bore of which a gas passes; and

an RF inductive coil wrapped around said outer tube to couple RF energy into said center bore to excite said gas into a plasma.

2. The plasma tube of claim 1, wherein said inner tube has a porosity of between 30 and 80%.

3. The plasma tube of claim 2, wherein said porosity is between 50 and 60%.

4. The plasma tube of claim 1, wherein said inner tube is doped with a catalyst for promoting reactions of said gas.

5. The plasma tube of claim 4, wherein said catalyst is selected from the group consisting of nickel and platinum.

6. The plasma tube of claim 1, wherein each of said inner and outer tube comprises a respective ceramic selected from the group consisting of alumina, aluminum nitride, calcium fluoride, silicon carbide, and boron nitride.

7. A plasma tube, comprising:

a vacuum sealing ceramic outer tube;

a porous ceramic inner tube having a porosity of between 30 and 80% and disposed within said outer tube through a center bore of which a gas passes, wherein said outer tube is coated onto said inner tube; and

an RF inductive coil wrapped around said outer tube to couple RF energy into said center bore to excite said gas into a plasma.

8. The plasma tube of claim 7, wherein said inner tube is doped with a catalyst for promoting reactions of said gas.

9. A plasma tube, comprising:

a first dielectric, vacuum sealing tube;

a second dielectric tube disposed inside said first tube having a porosity of between 30 and 80% and including a central bore; and

electromagnetic means positioned on a side of said first tube capable of exciting a gas contained in said central bore into a plasma.

10. The plasma tube of claim 9, wherein said electromagnetic means comprise an inductive coil wrapped around said first tube.

11. The plasma tube of claim 9, wherein said electromagnetic means comprises a microwave cavity directed at said side of said first tube.

12. The plasma tube of claim 9, wherein said each of said first and second tubes comprises a respective ceramic selected from the group consisting of alumina, aluminum nitride, calcium fluoride, silicon carbide, and boron nitride.

13. The plasma tube of claim 9, wherein said second tube comprises a catalytic material.

14. The plasma tube of claim 13, wherein said catalytic material is selected from the group consisting of nickel and platinum.

15. The plasma tube of claim 9, wherein said second dielectric tube is slidably fitted within said first dielectric tube.

16. A self-cleaning semiconductor processing system, comprising:

a vacuum chamber capable of holding therein a substrate to be processed in a processing gas supplied to said chamber;

a vacuum pumping system removing said processing gas and gaseous products of said processing gas from said vacuum chamber through a pumping port;

an abatement plasma system and said vacuum pumping system and comprising

a vacuum sealing outer ceramic tube,

a porous inner ceramic tube having a porosity of between 30 and 80% and disposed inside of said outer tube and having an inner bore connected in a pumping path between said pumping port and a downstream pump of said vacuum pumping system, and

an inductive coil wrapped around said outer tube and connectable to a source of RF power.

17. The processing system of claim 16, further comprising a source of oxidizing gas connected to said pumping path between said pumping port and said abatement plasma system.

18. The processing system of claim 16, wherein said inner ceramic tube includes a catalyst embedded therein.

19. The processing system of claim 18, wherein said catalyst is selected from the group consisting of nickel and platinum.

20. The processing system of claim 16, wherein said processing system is a plasma etching system receiving a halogen-containing gas as an etching gas.