Plasma uniformity control by gas diffuser curvature

• US 20060228496A1
• Filed: 07/01/2005
• Published: 10/12/2006
• Est. Priority Date: 05/12/2004
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Park, Beom Soo, Choi, Soo Young, White, John M., Tiner, Robin L.
• Granted Patent: US 8,074,599 B2
• Time in Patent Office: Days
• US Class Current: 427/569
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H01J 37/32449 Gas control, e.g. control of the gas flow

Abstract

Embodiments of a gas distribution plate for distributing gas in a processing chamber are provided. In one embodiment, a gas distribution assembly for a plasma processing chamber comprises a diffuser plate with gas passages passing between its upstream and downstream sides and hollow cathode cavities at the downstream side of the gas passages. The downstream side of the diffuser plate has a curvature to improve the thickness uniformity and film property uniformity of thin films deposited by PECVD, particularly SiN and amorphous silicon films. The curvature is preferably described by an arc of a circle or ellipse, the apex thereof located at the center point of the diffuser plate. In one aspect, the hollow cathode cavity volume density, surface area density, or the cavity density of the diffuser increases from the center of the diffuser to the outer edge. Methods for manufacturing such a diffuser plate are also provided.

Claims

1. A gas distribution plate assembly for a plasma processing chamber, comprising:

a diffuser plate having an upstream side and a downstream side, wherein the downstream side has a curvature that is substantially concave.

2. The gas distribution plate assembly of claim 1, wherein the diffuser plate size is at least 1,200,000 mm².

3. The gas distribution plate assembly of claim 1, wherein the surface of the downstream side of the diffuser plate is non-anodized bare aluminum.

4. The gas distribution plate assembly of claim 1, wherein the maximum displacement of the surface of the curved downstream side of the diffuser plate is between about 0.01 % and about 3% of the equivalent radius of the diffuser plate.

35. The gas distribution plate assembly of claim 1, wherein the curvature of the downstream side of the diffuser plate is described by an arc and the arc has a segment that has a circular or elliptical shape.

36. The gas distribution plate assembly of claim 1, wherein the curvature of the downstream side of the diffuser plate is described by an arc and the arc has a segment that has an exponential, second-order, third-order, sinusoidal, or hyperbolic shape.

5. A gas distribution plate assembly for a plasma processing chamber, comprising a diffuser plate having an upstream side and a downstream side, wherein the downstream side has a substantially concave curvature, wherein the diffuser plate comprises:

a first gas passage formed in a center region of the diffuser plate and in fluid communication with the upstream side and the downstream side, wherein the first gas passage comprises;

a first orifice in fluid communication with the upstream side; and

a first hollow cathode cavity positioned substantially adjacent to the downstream side of the gas passage, the first hollow cathode cavity comprising;

a first cathode cavity surface area;

a first cathode cavity volume; and

a first cathode cavity opening coincident with the surface of the downstream side;

a second gas passage formed in an edge region of the diffuser plate and in fluid communication with the upstream side and the downstream side, wherein the second gas passage comprises;

a second orifice in fluid communication with the upstream side; and

a second hollow cathode cavity positioned substantially adjacent to the downstream side of the gas passage, the second hollow cathode cavity comprising;

a second cathode cavity surface area;

a second cathode cavity volume; and

a second cathode cavity opening coincident with the surface of the downstream side;

wherein the cathode cavity surface area and/or cathode cavity volume increases from the first gas passage to the second gas passage.

6. The gas distribution plate assembly of claim 5, wherein the first hollow cathode cavity further comprises:

a first cathode cavity flaring angle;

a first cathode cavity depth; and

a first cathode cavity opening diameter; and

the second hollow cathode cavity further comprises;

a second cathode cavity flaring angle;

a second cathode cavity depth; and

a second cathode cavity opening diameter;

wherein one or more attributes increase in the first gas passage relative to the second gas passage and the one or more attributes are selected from the group consisting of the cathode cavity flaring angle, cathode cavity depth, cathode cavity surface area, cathode cavity volume or cathode cavity opening diameter.

7. The gas distribution plate assembly of claim 6, wherein the first cathode cavity diameter is no less than about 0.1 inch and the second cathode cavity diameter is no more than about 1.0 inch.

8. The gas distribution plate assembly of claim 6, wherein the first cathode cavity depth is no less than about 0.1 inch and the second cathode cavity depth is no more than about 2.0 inch.

9. The gas distribution plate assembly of claim 6, wherein the first cathode cavity flaring angle is no less than about 10 degrees and the second cathode cavity flaring angle is no more than about 50 degrees.

10. The gas distribution plate assembly of claim 5, wherein the center region further comprises:

a plurality of gas passages in fluid communication with the upstream side and the downstream side, wherein each gas passage in the plurality of gas passages comprises;

a cathode cavity surface area disposed on the downstream side; and

a cathode cavity volume disposed on the downstream side; and

a first hollow cathode cavity density; and

the edge region further comprises;

a plurality of gas passages in fluid communication with the upstream side and the downstream side, wherein each gas passage in the plurality of gas passages comprises;

a cathode cavity surface area disposed on the downstream side; and

a cathode cavity volume disposed on the downstream side; and

a second hollow cathode cavity density.

11. The gas distribution plate assembly of claim 10, wherein the first hollow cathode cavity density is equal to the second hollow cathode cavity density and the spacing between gas passages is no more than about 0.6 inches.

12. The gas distribution plate assembly of claim 10, wherein the first hollow cathode cavity density is less than the second hollow cathode cavity density.

13. The gas distribution plate assembly of claim 5, wherein the diffuser plate is rectangular.

14. The gas distribution plate assembly of claim 5, wherein the diffuser plate size is at least 1,200,000 mm².

15. The gas distribution plate assembly of claim 10, wherein the cathode cavity surface area or the cathode cavity volume of the plurality of gas passages in the center region and edge region gradually increases in size from the center to edge of the diffuser plate.

16. The gas distribution plate assembly of claim 12, wherein the diffuser plate further comprises:

a third region disposed between the center region and the edge region, the third region comprising a plurality of gas passages in fluid communication with the upstream side and the downstream side; and

a third hollow cathode cavity density.

17. The gas distribution plate assembly of claim 16, wherein the first hollow cathode cavity density is no less than about 10% of the second hollow cathode cavity density.

18. The gas distribution plate assembly of claim 5, wherein the surface of the downstream side of the diffuser plate is non-anodized bare aluminum.

19. The gas distribution plate assembly of claim 5, wherein the maximum displacement of the surface of the curved downstream side of the diffuser plate is between about 0.01 % and about 3% of the equivalent radius of the diffuser plate.

20. A plasma processing chamber, comprising:

a diffuser plate having an upstream side, a downstream side and a diffuser plate size of at least about 1,200,000 mm²;

a substrate support adjacent the downstream side of the diffuser plate; and

a spacing between the diffuser plate and the substrate support, wherein the spacing is larger in a center region than in an edge region.

21. The plasma processing chamber of claim 20, wherein the diffuser plate has a curvature.

22. The plasma processing chamber of claim 20, wherein the substrate support has a curvature.

23. The plasma processing chamber of claim 20, wherein the diffuser plate has a first curvature and the substrate support has a second curvature.

24. The plasma processing chamber of claim 20, wherein the diffuser plate further comprises a plurality of cathode cavities in a center region and a plurality of cathode cavities in an edge region, wherein the cathode cavity surface area, the cathode cavity volume or the cathode cavity density increases from the center region to the edge region.

25. A method of depositing a thin film on a substrate, comprising:

placing a substrate on a substrate support that is mounted in a processing region of a processing chamber;

flowing a process fluid through a diffuser plate toward a substrate supported on a substrate support, wherein the diffuser plate has an upstream side and a downstream side and the downstream side has a substantially concave curvature; and

creating a plasma between the downstream side of the diffuser plate and the substrate support.

26. The method of claim 25, wherein the diffuser plate further comprises a plurality of gas passages in fluid communication with the upstream and downstream sides of the diffuser plate, each gas passage comprising a hollow cathode cavity in fluid communication with the downstream side.

27. The method of claim 25, wherein the diffuser plate is rectangular.

28. The method of claim 25, wherein the diffuser plate size is at least 1,200,000 mm².

29. The method of claim 25, wherein the maximum displacement of the surface of the curved downstream side of the diffuser plate is between about 0.01% and 3% of the equivalent radius of the diffuser plate.

30. The method of claim 26, further comprising varying the volumes, surface areas, or density of the hollow cathode cavities across the diffuser plate as required to obtain the desired thin film thickness and property uniformity.

31. The method of claim 25, including adjusting the curvature of the curved down-stream side of the gas diffuser plate as required to obtain the desired thin film thickness and property uniformity.

32. The method of claim 25, wherein the process fluid is a silicon-containing fluid.

33. The method of claim 25, wherein the process fluid is a silicon-containing gas.

34. The method of claim 25, wherein the process fluid is a vaporized silicon containing liquid.