Plasma chamber equipped with temperature-controlled focus ring and method of operating

• US 20040005726A1
• Filed: 07/03/2002
• Published: 01/08/2004
• Est. Priority Date: 07/03/2002
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Huang, Chuan-Chieh
• Granted Patent: US 6,767,844 B2
• Time in Patent Office: Days
• US Class Current: 438/14
• CPC Class Codes: H01J 37/32642 Focus rings
• CPC Class Codes: H01L 21/67069 for drying etching
• CPC Class Codes: H01L 21/67109 mainly by convection
• CPC Class Codes: H01L 21/67248 Temperature monitoring

Abstract

A temperature-controlled focus ring assembly for use in a plasma chamber that includes a focus ring surrounding a wafer pedestal for confining plasma ions to a top surface of a wafer positioned on the wafer pedestal; a heat transfer means in intimate contact with the focus ring for decreasing or increasing the temperature of the focus ring; and a controller for controlling the temperature of the focus ring to a predetermined value. The invention further discloses a method for operating a plasma chamber equipped with a temperature-controlled focus ring assembly.

Claims

1. A focus ring assembly for use in a plasma chamber comprising:

a focus ring surrounding a wafer pedestal for confining plasma ions to a top surface of a wafer positioned on said wafer pedestal;

a heat transfer means in intimate contact with said focus ring for decreasing or increasing a temperature of the focus ring; and

a controller for controlling the temperature of the focus ring to a preset value.

2. A focus ring assembly for use in a plasma chamber according to claim 1, wherein said focus ring is fabricated of a material that adsorbs plasma ions on a top surface of the focus ring.

3. A focus ring assembly for use in a plasma chamber according to claim 1, wherein said focus ring is fabricated of silicon and said process chamber generates fluorine-containing plasma.

4. A focus ring assembly for use in a plasma chamber according to claim 1, wherein said heat transfer means is in intimate contact with a bottom surface of said focus ring.

5. A focus ring assembly for use in a plasma chamber according to claim 1, wherein said heat transfer means being a cooling means.

6. A focus ring assembly for use in a plasma chamber according to claim 1, wherein said heat transfer means being a heating means.

7. A focus ring assembly for use in a plasma chamber according to claim 1, wherein said heat transfer means being formed in a ring shape having a planar top surface area substantially the same as a bottom planar surface area of said focus ring.

8. A focus ring assembly for use in a plasma chamber according to claim 1, wherein said focus ring surrounds an electrostatic wafer chucking device.

9. A focus ring assembly for use in a plasma chamber according to claim 1, wherein said focus ring is fabricated of silicon and is sufficiently cooled such that substantially no fluorine ions or radicals are adsorbed on a top surface of said focus ring.

10. A focus ring assembly for use in a plasma chamber according to claim 1, wherein said focus ring is controlled to a temperature within a range of 100°

C.±

30°

C.

11. A plasma chamber equipped with a temperature-controlled focus ring comprising:

a chamber enclosure defining a cavity therein capable of maintaining a pressure not higher than 1 Torr;

a plasma generating means for producing a plasma in said cavity;

a wafer pedestal for holding a wafer thereon;

a focus ring surrounding said wafer pedestal for confining plasma ions to a top surface of said wafer held on said wafer pedestal; and

a heat transfer means in intimate contact with said focus ring for controlling a temperature of said focus ring.

12. A plasma chamber equipped with a temperature-controlled focus ring according to claim 11, wherein said wafer pedestal is an electro-static wafer chucking device.

13. A plasma chamber equipped with a temperature-controlled focus ring according to claim 11 further comprising a controller for controlling a temperature of said focus ring to a predetermined value.

14. A plasma chamber equipped with a temperature-controlled focus ring according to claim 11, wherein said plasma produced in said chamber cavity is a fluorine-containing plasma for etching oxide layers on a wafer.

15. A plasma chamber equipped with a temperature-controlled focus ring according to claim 11, wherein said focus ring is fabricated of a material that adsorbs plasma ions or radicals on a top surface of the focus ring.

16. A plasma chamber equipped with a temperature-controlled focus ring according to claim 11, wherein said focus ring is fabricated of silicon.

17. A plasma chamber equipped with a temperature-controlled focus ring according to claim 11, wherein said heat transfer means controls a temperature of said focus ring within a range of 100°

C.±

30°

C.

18. A method for operating a plasma chamber that is equipped with a temperature-controlled focus ring comprising the steps of:

providing a plasma chamber having a chamber enclosure defining a cavity therein, a plasma generating means, a wafer pedestal, a focus ring surrounding said wafer pedestal, and a heat transfer means in intimate contact with said focus ring;

mounting a wafer to be processed on top of said wafer pedestal;

controlling a temperature of said focus ring by said heat transfer means to a predetermined temperature; and

igniting a plasma in said cavity and substantially confining said plasma to a top surface of said wafer by said temperature-controlled focus ring.

19. A method for operating a plasma chamber that is equipped with a temperature-controlled focus ring according to claim 18 further comprising the steps of:

providing a focus ring fabricated of silicon; and

igniting a plasma comprising fluorine ions in said cavity.

20. A method for operating a plasma chamber that is equipped with a temperature-controlled focus ring according to claim 18 further comprising the step of controlling a temperature of said focus ring by said heat transfer means to within a range of 100°

C.±

30°

C.