Optical emission interferometry for PECVD using a gas injection hole

• US 20070039548A1
• Filed: 08/10/2006
• Published: 02/22/2007
• Est. Priority Date: 08/18/2005
• Status: Active Grant

• Current Assignee: Plasma-Therm Corporation
• Original Assignee: Plasma-Therm Corporation
• Inventors: Johnson, David
• Granted Patent: US 7,833,381 B2
• Time in Patent Office: Days
• US Class Current: 118/665
• CPC Class Codes: C23C 16/52 Controlling or regulating the coating process C23C16/45557, C23C16/279 take precedence
• CPC Class Codes: G01B 11/0658 with measurement of emissivity or reradiation
• CPC Class Codes: G01B 11/0683 measurement during deposition or removal of the layer
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: H01J 37/32972 Spectral analysis

Abstract

The present invention provides a method and apparatus for improving optical sensing of a plasma process through the use of a fiber optic sensor placed within a standard showerhead hole of a standard gas showerhead positioned in an upper electrode of a plasma system during the plasma processing of a substrate. A film property can be calculated based on the measured plasma emission from the surface of the substrate. The film property can be film deposition rate, refractive index, film thickness, etc. Based on the measured film property, the plasma processing of the substrate can be adjusted and/or terminated. In addition, a window is provided that is positioned in the upper electrode assembly for viewing the plasma emission through the standard showerhead hole.

Claims

1. A plasma apparatus for processing a substrate comprising:

a vacuum chamber;

at least one power supply for generating the plasma in said vacuum chamber;

a substrate pedestal for supporting the substrate;

an upper electrode assembly having a gas distribution system having a plurality of standard showerhead holes;

a detector in optical communication with at least one of said standard showerhead holes, said detector measuring the plasma emission transmitted through said standard showerhead holes; and

a control system in electrical communication with said detector and said power supply.

2. The apparatus according to claim 1 further comprising a window positioned in said upper electrode assembly for viewing the plasma emission through said standard showerhead holes.

3. The apparatus according to claim 1 wherein said window is not exposed to the plasma.

4. The apparatus according to claim 1 wherein said window is located to transmit plasma emission reflected normally from the substrate.

5. The apparatus according to claim 1 wherein said window is located away from the substrate.

6. The apparatus according to claim 1 wherein said upper electrode is RF grounded.

7. The apparatus according to claim 1 wherein said upper electrode is RF powered.

8. The apparatus according to claim 1 wherein said substrate pedestal is RF grounded.

9. The apparatus according to claim 1 wherein said substrate pedestal is RF powered.

10. A method for monitoring plasma processing of a substrate, the method comprising the steps of:

positioning the substrate on a substrate pedestal within a vacuum chamber;

introducing a gas through a plurality of standard showerhead holes of a gas distribution system of an upper electrode assembly;

generating a plasma from said gas within said vacuum chamber;

monitoring said plasma during plasma processing of the substrate, said monitoring occurring by collecting and measuring the plasma emission transmitted through at least one standard showerhead hole, using optical components positioned within said gas distribution system of said upper electrode assembly; and

terminating said plasma based on said monitoring step.

11. The method according to claim 10 wherein said showerhead is grounded.

12. The method according to claim 10 wherein said showerhead is RF powered.

13. The method according to claim 10 wherein said plasma emission is reflected from a surface.

14. The method according to claim 10 wherein said plasma emission is reflected from a surface of the substrate to be plasma processed.

15. The method according to claim 14 wherein a film property is calculated based on the measured plasma emission from the surface of the substrate.

16. The method according to claim 15 wherein said film property is calculated based on measuring plasma emission that is reflected normally from the substrate to be plasma processed.

17. The method according to claim 15 wherein said film property is film deposition rate.

18. The method according to claim 15 wherein said film property is refractive index.

19. The method according to claim 15 wherein said film property is film thickness.

20. The method according to claim 15 wherein the plasma processing of the substrate is adjusted based on said film property.

21. The method according to claim 15 wherein the plasma processing of the substrate is terminated based on said film property.

22. The method according to claim 15 wherein the plasma processing of the substrate is an etch process.

23. The method according to claim 15 wherein the plasma processing of the substrate is a deposition process.

24. The method according to claim 15 wherein the plasma processing of the substrate further comprising the generation of a plasma from a nitrogen containing gas.

25. The method according to claim 15 wherein the plasma emission is measured at a wavelength.

26. The method according to claim 25 wherein the plasma emission is measured in the range of 300 to 400 nanometers.