Plasma baffle assembly

• US 20030092278A1
• Filed: 11/12/2002
• Published: 05/15/2003
• Est. Priority Date: 11/13/2001
• Status: Abandoned Application

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Fink, Steven T.
• Application Number:
  US10/291,533
• Publication Number:
  US 20030092278A1
• Time in Patent Office: Days
• US Class Current: 438/710
• CPC Class Codes: H01J 37/32623 Mechanical discharge control means
• CPC Class Codes: H01J 37/32633 Baffles

Abstract

A plasma processing apparatus and a method for improving plasma characteristics by controlling the dissociation and ionization in the plasma are described. The method includes providing a flow of precursor gas into a process chamber, and evacuating excess gas from process chamber, disposing a substrate material on a substrate holder in the process chamber, forming a plasma from the precursor gas in a plasma volume within the process chamber and attenuating the plasma in a space surrounding the substrate with a baffle assembly and the substrate holder. The walls of the baffle assembly surround the outside edges and a portion of a surface of the substrate holder opposed to a surface on which the substrate is disposed.

Claims

1. A method for attenuating a plasma around a process region, the method comprising:

disposing a substrate material on a substrate holder in the process chamber;

providing a flow of precursor gas into the process chamber;

evacuating excess gas from the process chamber;

forming a plasma from said precursor gas in a plasma volume within the process chamber; and

attenuating said plasma in a space proximate the substrate with a baffle assembly.

2. The method for attenuating a plasma around process region as recited in claim 1, further comprising surrounding the space proximate the substrate with a cylindrically shaped baffle assembly.

3. The method for attenuating a plasma around a process region as recited in claim 1, further comprising surrounding the space proximate the substrate with an inner wall of a conically shaped baffle assembly, wherein a smaller annular section of the conical shape is oriented towards the substrate holder.

4. The method for attenuating a plasma around a process region as recited in claim 1, further comprising surrounding the space proximate the substrate with an inner wall of a spherically shaped baffle assembly.

5. The method for attenuating a plasma around a process region as recited in claim 1, further comprising surrounding the space proximate the substrate with an inner wall of a conically shaped baffle assembly, wherein a larger annular section of the conical shape is oriented towards the substrate holder.

6. The method for attenuating a plasma around a process region as recited in claim 1, further comprising surrounding the space proximate the substrate with lateral polygonal faces of a polygonal baffle assembly.

7. The method for attenuating a plasma around a process region as recited in claim 1, further comprising surrounding the space proximate the substrate with said baffle assembly, wherein said baffle assembly comprises a combination of shapes selected from the group consisting of cylindrical, conical, polygonal, and spherical shapes.

8. The method for attenuating a plasma around a process region as recited in claim 1, further comprising positioning said baffle assembly between a bias electrode and a plasma generating electrode wherein the bias electrode comprises the substrate holder and the plasma generating electrode supports the baffle assembly.

9. The method for attenuating a plasma around a process region as recited in claim 1, further comprising enclosing the substrate holder with said baffle assembly during a process and permitting substrate exchange when the substrate holder is lowered to a transfer position.

10. The method for attenuating a plasma around a process region as recited in claim 9, wherein said plasma is attenuated in an area bounded by the lower electrode, the upper electrode and the walls of said baffle assembly.

11. The method for attenuating a plasma around a process region as recited in claim 1, wherein said baffle assembly is perforated by high aspect ratio holes.

12. The method for attenuating a plasma around a process region as recited in claim 11, further comprising exhausting excess gas through the holes in the baffle assembly to a pumping system attached to the process chamber.

13. The method for attenuating a plasma around a process region as recited in claim 1, further comprising controlling the uniformity of the plasma density in areas where desired by positioning features comprising holes of various shapes and dimensions in the baffle assembly.

14. The method for attenuating a plasma around a process region as recited in claim 1, further comprising controlling the uniformity of the plasma density in areas where desired by adjusting the length of said baffle assembly.

15. The method for attenuating a plasma around a process region as recited in claim 1, further comprising controlling the uniformity of the plasma density in areas where desired by adjusting the diameter of said baffle assembly.

16. The method for attenuating a plasma around a process region as recited in claim 1, further comprising controlling the uniformity of the plasma density in areas where desired by adjusting the position of said baffle assembly.

17. The method for attenuating a plasma around a process region as recited in claim 1, wherein said baffle assembly is perforated with slots positioned to control said plasma.

18. The method for attenuating a plasma around a process region as recited in claim 1, wherein said baffle assembly is constructed from a material selected from the group comprising quartz and ceramics.

19. The method for attenuating a plasma around a process region as recited in claim 18, wherein said ceramics consist of porous ceramics.

20. The method for attenuating a plasma around a process region as recited in claim 1, wherein said baffle assembly is constructed from an electrically conductive material.

21. The method for attenuating a plasma around a process region as recited in claim 20, wherein said baffle assembly is coated with a protective barrier.

22. The method for attenuating a plasma around a process region as recited in claim 20, wherein said baffle assembly consists of wire-grid.

23. The method for attenuating a plasma around a process region as recited in claim 20, wherein said baffle assembly is biased with voltage.

24. The method for attenuating a plasma around a process region as recited in claim 1, wherein the substrate holder is slidable between positions respectively inside and outside the baffle assembly.

25. The method for attenuating a plasma around a process region as recited in claim 1, wherein the baffle assembly further comprises a shield ring component.

26. A plasma process apparatus with baffle assembly comprising:

a process chamber;

a plasma generating system configured and arranged to produce a plasma in the process chamber;

a gas source configured to introduce gases into the process chamber;

a pressure-control system to maintain a selected pressure within the process chamber;

a substrate holder configured to hold a substrate during substrate processing; and

a baffle assembly disposed radially outward of said substrate to attenuate said plasma proximate to said substrate.

27. The plasma process apparatus with baffle assembly as recited in claim 26, wherein said baffle assembly is a shape selected from the group consisting of a cylindrical form, a conical form, a polygonal form and a spherical form.

28. The plasma process apparatus with baffle assembly as recited in claim 26, wherein said baffle assembly comprises high aspect ratio holes perforated on a wall of said baffle assembly.

29. The plasma process apparatus with baffle assembly as recited in claim 26, wherein said baffle assembly comprises slots perforated on a wall of said baffle assembly.

30. The plasma process apparatus with baffle assembly as recited in claim 26, wherein said baffle assembly is constructed from a material selected from the group consisting of quartz and ceramics.

31. The plasma process apparatus with baffle assembly as recited in claim 26, wherein said baffle assembly is constructed from an electric conductive material.

32. The plasma process apparatus with baffle assembly as recited in claim 31 wherein said baffle assembly is coated with a protective barrier.

33. The plasma process apparatus with baffle assembly as recited in claim 31, wherein said baffle assembly is constructed from an electric conducting wire-grid.

34. The plasma process apparatus with baffle assembly as recited in claim 31, wherein said baffle assembly is biased with voltage.

35. The plasma process apparatus with baffle assembly as recited in claim 26, wherein said substrate holder is slidable between positions respectively inside and outside said baffle assembly.