DIFFUSER PLATE WITH SLIT VALVE COMPENSATION

• US 20080020146A1
• Filed: 07/20/2007
• Published: 01/24/2008
• Est. Priority Date: 05/12/2004
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: CHOI, SOO, White, John
• Granted Patent: US 8,328,939 B2
• Time in Patent Office: Days
• US Class Current: 427/446
• CPC Class Codes: C23C 16/345 Silicon nitride
• CPC Class Codes: C23C 16/455 characterised by the method used for introducing gases into reaction chamber or for modifying gas flows in reaction chamber
• CPC Class Codes: C23C 16/45565 Shower nozzles
• CPC Class Codes: C23C 16/5096 Flat-bed apparatus
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H01J 37/32596 Hollow cathodes

Abstract

The present invention generally comprises a diffuser plate for a PECVD chamber. The diffuser plate comprises a plurality of hollow cathode cavities. The edge of the diffuser plate that will reside closest to a slit valve within a processing chamber may have the shape and/or size of the hollow cathode cavities adjusted to compensate for the proximity to the slit valve. By adjusting the shape and/or size of the hollow cathode cavities closest to the slit valve, the diffuser plate may permit a uniform plasma distribution across the processing chamber and thus, a uniform film thickness upon a substrate during a PECVD process.

Claims

1. A gas distribution plate assembly, comprising:

a diffuser plate element having an upstream side, a downstream side, a first edge to be disposed adjacent a slit valve in a processing chamber, a center, and a second edge; and

a plurality of gas passages passing between the upstream side and the downstream side, the plurality of gas passages comprise;

a first gas passage having a first hollow cathode cavity disposed adjacent the first edge of the diffuser plate element;

a second gas passage having a second hollow cathode cavity disposed adjacent the center of the diffuser plate element; and

a third gas passage having a third hollow cathode cavity disposed adjacent the second edge, wherein the first hollow cathode cavity, second hollow cathode cavity, and third hollow cathode cavity have different volumes.

2. The assembly of claim 1, wherein the third hollow cathode cavity volume is greater than the first hollow cathode cavity volume and the second hollow cathode cavity volume.

3. The assembly of claim 1, wherein each gas passage comprises:

an orifice opening having a length and a diameter sufficient to promote a substantially uniform back pressure, the orifice opening coupled with a hollow cathode cavity.

4. The assembly of claim 3, wherein each orifice opening comprises a substantially identical length and diameter.

5. The assembly of claim 1, wherein the diffuser plate element comprises at least one corner portion having a fourth hollow cathode cavity, and wherein the fourth hollow cathode cavity volume is less than the third hollow cathode cavity volume.

6. The assembly of claim 1, wherein the downstream side comprises a substantially concave portion.

7. A plasma processing chamber, comprising:

a chamber body having a plurality of walls;

one or more slit valves disposed in at least one of the plurality of walls; and

a diffuser plate comprising;

a diffuser plate element having an upstream side, a downstream side, a first edge to be disposed adjacent a slit valve of the one or more slit valves, a center, and a second edge; and

a plurality of gas passages passing between the upstream side and the downstream side, the plurality of gas passages comprise;

a first gas passage having a first hollow cathode cavity disposed adjacent the first edge of the diffuser plate element;

a second gas passage having a second hollow cathode cavity disposed adjacent the center of the diffuser plate element; and

a third gas passage having a third hollow cathode cavity disposed adjacent the second edge, wherein the first hollow cathode cavity, second hollow cathode cavity, and third hollow cathode cavity have different volumes.

8. The chamber of claim 7, wherein each gas passage comprises:

an orifice opening having a length and a diameter sufficient to promote a substantially uniform back pressure, the orifice opening coupled with a hollow cathode cavity.

9. The chamber of claim 8, wherein each orifice opening comprises a substantially identical length and diameter.

10. The chamber of claim 7, wherein the third hollow cathode cavity volume is greater than the first hollow cathode cavity volume and the second hollow cathode cavity volume.

11. The chamber of claim 7, wherein the diffuser plate element comprises at least one corner portion having a fourth hollow cathode cavity, and wherein the fourth hollow cathode cavity volume is less than the third hollow cathode cavity volume.

12. The chamber of claim 7, wherein the downstream side comprises a substantially concave portion.

13. A plasma processing method, comprising:

flowing a processing gas through a diffuser plate, the diffuser plate having a plurality of gas passages disposed therethrough and arranged such that a first gas passage disposed adjacent a slit valve is different than both a second gas passage disposed adjacent a center of the diffuser plate and a third gas passage disposed adjacent and edge of the diffuser plate;

biasing the diffuser plate; and

igniting a plasma within the gas passages.

14. The method of claim 13, further comprising:

plasma processing a substrate disposed opposite the diffuser plate, wherein the igniting a plasma further comprises;

igniting a plasma in the first gas passage;

igniting a plasma in the second gas passage; and

igniting a plasma in the third gas passage.

15. The method of claim 14, wherein the method comprises plasma enhanced chemical vapor deposition.

16. The method of claim 15, wherein the plasma processing comprises depositing a substantially uniform thickness layer onto the substrate.

17. The method of claim 13, further comprising:

creating an asymmetrical hollow cathode plasma gradient across the diffuser plate.

18. The method of claim 13, wherein the diffuser plate comprises a substantially concave portion.

19. The method of claim 13, wherein each gas passage comprises:

an orifice hole having a length and a diameter sufficient to promote a uniform gas distribution across the upstream side; and

a hollow cathode cavity coupled with the orifice hole and the downstream side.

20. The method of claim 19, wherein the orifice holes are substantially identical.