Integrated wafer temperature sensors

• US 6,325,536 B1
• Filed: 07/10/1998
• Issued: 12/04/2001
• Est. Priority Date: 07/10/1998
• Status: Expired due to Term

• Current Assignee: SensArray Corp. (KLA Corporation)
• Original Assignee: SensArray Corp. (KLA Corporation)
• Inventors: Miller, Paul, Renken, Wayne Glenn, Gordon, Roy, Vandenabeele, Peter Michael Noel, Sun, Mei H.
• Primary Examiner(s): Gutierrez, Diego
• Assistant Examiner(s): De Jesús, Cydia M
• Application Number:
  US09/113,240
• Time in Patent Office: 1,243 Days
• Field of Search: 374/137, 374/161, 374/166, 374/131
• US Class Current: 374/161
• CPC Class Codes: G01K 11/3213 using changes in luminescence, e.g. at the distal end of the fibres

Abstract

Systems and methods are described for integrated (embedded) semiconductor wafer temperature measurement equipment and processes. An integrated wafer temperature measurement apparatus, comprising: a substrate; a placement resource formed in said substrate; a sensor lead located in said placement resource, said sensor lead having a first end and a second end; a sensor coupled to said first end of said sensor lead and located in said placement resource; and a sensor lead cover coupled to said substrate. The systems and methods provide advantages in that reliability is enhanced, installation and removal are facilitated, and accuracy is improved by obviating any shadowing of the substrate and reducing temperature gradients near the sensor.

Claims

1. A parameter measuring structure, comprising:

a substrate having opposing external surfaces,

a plurality of elongated cavities within the substrate between the opposing surfaces, the cavities individually having lengths defined by first and second ends, the second cavity ends being spaced apart from each other in directions across the surfaces,

a plurality of optical sensors of the parameter positioned within the individual cavities adjacent their respective second ends, and

at least one optical fiber entering the first ends of individual ones of the plurality of cavities from outside of the substrate and extending along the lengths of the cavities with ends of the optical fibers being coupled to the optical sensors of their respective cavities.

2. The structure of claim 1, wherein the optical sensors individually include phosphorescent material that emits radiation dependent upon the parameter being measured.

3. The structure of claim 1, wherein the optical sensors individually include a black body structure.

4. The structure of claim 1, wherein the optical sensors individually include an interferometric cavity.

5. The structure of any one of claims 1-4, wherein the parameter being measured is the temperature of the optical sensor.

6. The structure of any one of claims 1-4, wherein the optical sensors are attached to inside walls of the respective cavities.

7. The structure of any one of claims 1-4, wherein the optical sensors are attached to the ends of their respective optical fibers.

8. The structure of any one of claims 1-4, which additionally comprises an opaque layer positioned over the individual optical sensors to block ambient light outside of the structure from penetrating into areas including the sensors.

9. The structure of claim 1, wherein the substrate is formed of first and second pieces of material having respective internal surfaces that are attached together, the cavities being formed by the internal surface of the second piece of material positioned over grooves in the internal surface of the first piece of material.

10. The structure of claim 9, wherein the internal surfaces of the first and second pieces of material have the same size and shape.

11. The structure of claim 10, wherein the internal surfaces of the first and second pieces of material are circular with the same diameter.

12. The structure of claim 9, wherein the first piece of material is significantly larger that the second piece of material.

13. The structure of any one of claims 9-12;

wherein the first and second pieces of material have substantially the same thermal properties.

14. The structure of any one of claims 9-12, wherein the first and second pieces are made of a common material.

15. The structure of claim 14, wherein the common material is silicon.

16. The structure of any one of claims 9-12, wherein the first and second pieces protect the sensors and optical fibers in the cavities from a plasma ion bombardment of 8 watts per square centimeter.

17. The structure of any one of claims 9-12, wherein the first and second pieces are opaque to light radiation within a range of wavelengths less than 1.1 micron.

18. The structure of claim 1, wherein the first ends of the cavities individually form openings to an outside of the structure.

19. The structure of claim 1, wherein the first ends of the individual cavities are joined together within the substrate to an entrance passage through which the optical fibers pass from the outside of the substrate and into the first ends of said cavities.

20. The structure of either of claims 18 or 19, which additionally comprises an attachment of the optical fibers to the substrate outside of the cavities that relieves strain on the optical fibers within the cavities.

21. The structure of either of claims 18 or 19, wherein the opposing external surfaces of the substrate are flat surfaces that are parallel with each other.

22. The structure of claim 21, wherein the elongated cavities are parallel with the external surfaces.

23. A test structure for measuring a distribution of temperature thereacross, comprising:

a substrate having opposing external surfaces that are flat and parallel to each other,

a plurality of elongated cavities within the substrate between the opposing surfaces that extend in a direction parallel to said surfaces, the cavities individually having lengths defined by first and second ends, the second cavity ends being spaced apart from each other in directions across the surfaces,

a plurality of optical temperature sensors positioned within the individual cavities at their respective second ends,

a plurality of optical fibers including at least one optical fiber entering the first end of each of the plurality of cavities from outside of the substrate and extending along the length of its respective cavity to a position adjacent the second end of the cavity and coupled to the optical temperature sensor thereat, and

light opaque material positioned with respect to the individual optical temperature sensors to block light from reaching said sensors from outside of the test structure.

24. The structure of claim 23, wherein the optical sensors individually include phosphorescent material that emits radiation dependent upon its temperature.

25. The structure of claim 23, wherein the optical sensors individually include a black body structure.

26. The structure of either of claims 24 or 25, wherein the optical sensors are attached to inside walls of their respective cavities.

27. The structure of either of claims 24 or 25, wherein the optical sensors are attached to the ends of their respective optical fibers.

28. The structure of claim 23, wherein the substrate is formed of first and second pieces of material having respective internal surfaces that are attached together, the cavities being formed by the internal surface of the second piece of material positioned over grooves in the internal surface of the first piece of material.

29. The structure of claim 28, wherein the internal surfaces of the first and second pieces of material have the same size and shape.

30. The structure of claim 29, wherein the internal surfaces of the first and second pieces of material are circular with the same diameter.

31. The structure of claim 28, wherein the first piece of material is significantly larger that the second piece of material.

32. A method of measuring a distribution of temperature across a test structure within a plasma processing chamber, comprising positioning the test structure of any one of claims 23-25 or 28-31 within a plasma processing chamber.

33. The method of claim 32, additionally comprising bombarding the test structure with a density of ions of at least 8 watts per square centimeter.

34. The structure of any one of claims 28-31, wherein the first and second pieces of material have substantially the same thermal properties.

35. The structure of any one of claims 28-31, wherein the first and second pieces are made of a common material.

36. The structure of claim 35, wherein the common material is silicon.

37. The structure of any one of claims 28-31, wherein the first and second pieces protect the sensors and optical fibers in the cavities from a plasma ion bombardment of 8 watts per square centimeter.

38. The structure of any one of claims 28-31, wherein the first and second pieces are opaque to light radiation within a range of wavelengths less than 1.1 micron.

39. The structure of claim 23, wherein the first ends of the cavities individually form openings to an outside of the structure.

40. The structure of claim 23, wherein the first ends of the individual cavities are joined together within the substrate to an entrance passage through which the optical fibers pass from the outside of the substrate and into said first cavity ends.

41. The structure of either of claims 39 or 40, which additionally comprises an attachment of the optical fibers to the substrate outside of the cavities that relieves strain on the optical fibers within the cavities.