Apparatus for determining a temperature of a substrate and methods therefor

• US 20070064767A1
• Filed: 09/22/2005
• Published: 03/22/2007
• Est. Priority Date: 09/22/2005
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Graff, Keith
• Granted Patent: US 7,578,616 B2
• Time in Patent Office: Days
• US Class Current: 374/161
• CPC Class Codes: G01K 11/20 using thermoluminescent materials G01K11/32 takes precedence
• CPC Class Codes: G01K 11/3213 using changes in luminescence, e.g. at the distal end of the fibres

Abstract

An apparatus for measuring a temperature of a substrate is disclosed. The apparatus includes a phosphor material in thermal contact to the substrate, the phosphor material producing a fluorescent response in a first wavelength range when exposed to a electromagnetic radiation in a second wavelength range, the fluorescent response decaying at a decay rate that is related to a temperature of the phosphor material, and the phosphor material producing a first set of non volatile byproducts when exposed to a plasma. The apparatus also includes a barrier window positioned between the phosphor material and a plasma, wherein the barrier window allows at least a portion of the first wavelength and the second wavelength to be transmitted, and wherein the barrier window produces a second set of non volatile byproducts that is less than the first set of non volatile byproducts when exposed to the plasma, wherein when the electromagnetic radiation is transmitted to the phosphor material through the barrier window, the temperature is determined from the decay rate of the fluorescent response.

Claims

1. In a plasma processing system, an apparatus for measuring a temperature of a substrate;

comprising;

a phosphor material in thermal contact to said substrate, said phosphor material producing a fluorescent response in a first wavelength range when exposed to a electromagnetic radiation in a second wavelength range, said fluorescent response decaying at a decay rate that is related to a temperature of said phosphor material, and said phosphor material producing a first set of non volatile byproducts when exposed to a plasma;

a barrier window positioned between said phosphor material and a plasma, wherein said barrier window allows at least a portion of said first wavelength and said second wavelength to be transmitted, and wherein said barrier window produces a second set of non volatile byproducts that is less than said first set of non volatile byproducts when exposed to said plasma,

wherein when said electromagnetic radiation is transmitted to said phosphor material through said barrier window, said temperature is determined from said decay rate of said fluorescent response.

2. The apparatus of claim 1, wherein said phosphor material is a ceramic.

3. The apparatus of claim 2, wherein said barrier window comprises one of quartz, sapphire, glass, borosilicate, and MgF₂.

4. The apparatus of claim 3, wherein a sensor/transmitter transmits a second wavelength in said second wavelength range, and said sensor/transmitter measures a first wavelength in said first wavelength range.

5. The apparatus of claim 4, wherein said substrate is disposed on a chuck.

6. The apparatus of claim 5, wherein said sensor/transmitter is positioned in said chuck.

7. The apparatus of claim 6, wherein said barrier window is secured to said substrate with one of an adhesive, a friction fit, a pressure fit, and a gasket.

8. The apparatus of claim 7, wherein said phosphor material and said barrier window are positioned in a notch in said substrate.

9. In a plasma processing system, an apparatus of measuring a temperature of a substrate, comprising:

means of thermally coupling a phosphor material to said substrate, said phosphor material producing a fluorescent response in a first wavelength range when exposed to a electromagnetic radiation in a second wavelength range, said fluorescent response decaying at a decay rate that is related to a temperature of said phosphor material, and said phosphor material producing a first set of non volatile byproducts when exposed to a plasma;

means of positioning a barrier window between said phosphor material and a plasma, wherein said barrier window allows at least a portion of said first wavelength and said second wavelength to be transmitted, and wherein said barrier window produces a second set of non volatile byproducts that is less than said first set of non volatile byproducts when exposed to said plasma;

means of determining said temperature from said decay rate of said fluorescent response when said electromagnetic radiation is transmitted to said phosphor material through said barrier window.

10. The apparatus of claim 9, wherein said phosphor material is a ceramic.

11. The apparatus of claim 10, wherein said barrier window comprises one of quartz, sapphire, glass, borosilicate, and MgF₂.

12. The apparatus of claim 11, wherein a sensor/transmitter transmits a second wavelength in said second wavelength range, and said sensor/transmitter measures a first wavelength in said first wavelength range.

13. The apparatus of claim 12,.wherein said substrate is disposed on a chuck.

14. The apparatus of claim 13, wherein said sensor/transmitter is positioned in said chuck.

15. The apparatus of claim 14, wherein said barrier window is secured to said substrate with one of an adhesive, a friction fit, a pressure fit, and a gasket.

16. The apparatus of claim 15, wherein said phosphor material and said barrier window are positioned in a notch in said substrate.

17. In a plasma processing system, a method for measuring a temperature of a substrate, comprising:

thermally coupling a phosphor material to said substrate, said phosphor material producing a fluorescent response in a first wavelength range when exposed to a electromagnetic radiation in a second wavelength range, said fluorescent response decaying at a decay rate that is related to a temperature of said phosphor material, and said phosphor material producing a first set of non volatile byproducts when exposed to a plasma;

positioning a barrier window between said phosphor material and a plasma, wherein said barrier window allows at least a portion of said first wavelength and said second wavelength to be transmitted, and wherein said barrier window produces a second set of non volatile byproducts that is less than said first set of non volatile byproducts when exposed to said plasma;

determining said temperature from said decay rate of said fluorescent response when said electromagnetic radiation is transmitted to said phosphor material through said barrier window.

18. The method of claim 17, wherein said phosphor material is a ceramic.

19. The method of claim 18, wherein said barrier window comprises one of quartz, sapphire, glass, borosilicate, and MgF₂.

20. The method of claim 19, wherein a sensor/transmitter transmits a second wavelength in said second wavelength range, and said sensor/transmitter measures a first wavelength in said first wavelength range.

21. The method of claim 20, wherein said substrate is disposed on a chuck.

22. The method of claim 21, wherein said sensor/transmitter is positioned in said chuck.

23. The method of claim 22, wherein said barrier window is secured to said substrate with one of an adhesive, a friction fit, a pressure fit, and a gasket.

24. The method of claim 23, wherein said phosphor material and said barrier window are positioned in a notch in said substrate.

25. The method of claim 17, wherein said barrier window comprises an anti-reflection coating.