Cathode liner with wafer edge gas injection in a plasma reactor chamber

• US 20090056629A1
• Filed: 09/05/2007
• Published: 03/05/2009
• Est. Priority Date: 09/05/2007
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Todorow, Valentin N., Willwerth, Michael D., Paterson, Alexander M., Palagashvili, David, Katz, Dan
• Granted Patent: US 7,832,354 B2
• Time in Patent Office: Days
• US Class Current: 118/723.R
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H01J 37/32642 Focus rings
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/32137 of silicon-containing layers
• CPC Class Codes: H01L 2924/19042 being an inductor

Abstract

The disclosure concerns a wafer support for use in a plasma reactor chamber, in which the wafer support has a wafer edge gas injector adjacent and surrounding the wafer edge.

Claims

1. A plasma reactor for processing a workpiece, comprising:

a chamber enclosure comprising a sidewall and a ceiling;

a workpiece support in said chamber having a workpiece support surface facing said ceiling;

a cathode liner surrounding said workpiece support and having a top surface and a base and having plural internal gas flow channels extending from said base to said top surface;

a gas supply plenum at said base coupled to each of said internal gas flow channels; and

a process ring overlying said top surface of said cathode liner and having an inner edge that is adjacent a peripheral edge of said wafer support surface

a gas injector in said process ring having a gas injection path through said inner edge and facing said workpiece support surface, said gas injector being coupled to said plural internal gas flow channels; and

a gas supply system coupled to said gas supply plenum.

2. The reactor of claim 1 wherein said gas injection path through said inner edge comprises a continuous slit opening facing said workpiece support surface.

3. The reactor of claim 1 wherein said gas injection path through said inner edge comprises plural gas injection orifices.

4. The reactor of claim 1 wherein said gas injector comprises a gap in said process ring separating said process ring into upper and lower process rings.

5. The reactor of claim 4 further comprising an internal feed channel bounded by said process ring and said cathode liner, said plural internal gas flow channels coupled at said top surface to said feed channel, said feed channel coupled to said gap in said process ring.

6. The reactor of claim 1 wherein said inner edge is spaced from the periphery of said workpiece support surface by a distance less than about 1% of the diameter of said workpiece support surface.

7. The reactor of claim 1 further comprising a process gas disperser at said ceiling coupled to said gas supply system.

8. The reactor of claim 7 wherein said process gas disperser comprises inner and outer gas injection zones and respective independent gas flow channels to said inner and outer gas injection zones.

9. The reactor of claim 8 wherein gas flow rates to (a) said gas injector in said process ring, (b) said inner gas injection zone of said gas disperser and (c) said outer gas injection zone of said gas disperser are independently controllable.

10. The reactor of claim 9 wherein said gas supply system comprises a source of a first process gas coupled to said gas disperser and a source of a second process gas coupled to said gas injector in said process ring.

11. The reactor of claim 1 wherein said wafer support has a generally cylindrical axis of symmetry and said liner comprise a cylindrical wall coaxial with said wafer support.

12. The reactor of claim 11 wherein said gas injector comprises an annular slit.

13. The reactor of claim 12 wherein said wafer support surface has a peripheral edge corresponding to a peripheral edge of a wafer to be supported on said wafer support surface, said annular slit being separated from said peripheral edge by a distance less than about 1% of the diameter of said workpiece support surface.

14. A workpiece support for use in a plasma reactor, comprising:

a pedestal having a workpiece support surface;

a processing ring overlying a periphery of said pedestal and adjacent a peripheral boundary of said workpiece support surface;

a wafer edge gas injector in said process ring and having a gas injection opening generally facing a workpiece location overlying said workpiece support surface; and

a gas supply coupled to said wafer edge gas injector.

15. The workpiece support of claim 14 wherein said wafer edge gas injector comprises an annular slit opening.

16. The workpiece support of claim 14 further comprising:

a liner surrounding a side of said pedestal and having a top surface underlying said process ring;

plural axial channels inside said liner and extending through said liner to said top surface of said liner; and

an annular feed channel defined between said process ring and said liner, each of said plural axial channels coupled to said annular feed channel, said wafer edge gas injector coupled to said annular feed channel.

17. The workpiece support of claim 16 wherein said liner further comprises:

a bottom surface and a base underlying said bottom surface;

an annular plenum inside said base; and

said plural axial channels being coupled to said annular plenum.

18. The workpiece support of claim 14 wherein said liner comprise quartz.

19. For use in a plasma reactor, a workpiece support comprising a workpiece support surface and a wafer edge gas injector adjacent said workpiece support surface and having a gas injection path overlying said workpiece support surface.

20. The workpiece support of claim 19 wherein said wafer edge gas injector comprises an annular slit opening.