Method for repeatable temperature measurement using surface reflectivity

- Micron Technology, Inc.

A method is disclosed for continuously measuring the temperature of a semiconductor substrate in a chamber is disclosed. The first step of the method involves providing a substantially clean semiconductor substrate having a layer a reflective surface thereon into a chamber. A film is formed superjacent the surface by introducing a gas comprising at least one of N.sub.2, NH.sub.3, O.sub.2, N.sub.2 O, Ar, Ar--H.sub.2, H.sub.2, GeH.sub.4, or any fluorine based gas and photon energy in situ. The photon energy, having a wavelength substantially in the absorption band of silicon, generates a temperature substantially within the range of 500.degree. C. to 1250.degree. C. Subsequently, the reflectivity of the surface is measured prior to introducing the gas, and continuously, while forming the film until the film is substantially formed. The substrate is exposed to photon energy having a power level responsive to the measured reflectivities of the film.

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Claims

1. A method for measuring the temperature of a substrate comprising the steps of:

providing a su in a chamber, said substrate, having a reflective surface;
exposing said substrate to a gas and radiant energy to form a film superjacent said substrate, said energy having a power level;
comparing the reflectivity of said surface prior to said exposing and while said film is being formed, said power level responsive to differences in said compared reflectivity.

2. A method for measuring the temperature of a substrate according to claim 1, wherein said method is performed in situ under substantially high vacuum.

3. A method for measuring the temperature of a substrate, according to claim 1, wherein said surface comprises a layer formed superjacent said substrate.

4. A method for measuring the temperature of a substrate, according to claim 3, wherein said layer comprises a masking pattern.

5. A method for measuring the temperature of a substrate, according to claim 3, wherein said layer is formed by at least one of Chemical Vapor Deposition ("CVD"), Rapid Thermal Processing Chemical Vapor Deposition ("RTPCVD"), Low Pressure Chemical Vapor Deposition ("LPCVD"), Molecular Beam Epitaxy ("MBE"), Reactive Ion Sputtering ("RIS"), Physical Vapor Deposition ("PVD") and Plasma Processing.

6. A method for measuring the temperature of a substrate, according to claim 5, wherein said layer functions as a barrier layer, said layer comprising at least one of TiN and TaN.

7. A method for measuring the temperature of a substrate, according to claim 1, wherein the reflectivity of said surface prior to said exposing is continuously compared with the reflectivity of said surface during said exposing until said film is substantially formed.

8. A method for measuring the temperature of a substrate, according to claim 1, wherein said substrate comprises at least one of single crystal silicon, polycrystalline silicon, and amorphous silicon.

9. A method for measuring the temperature of a substrate, according to claim 8, wherein said energy compresses photon energy substantially in the absorption band of said substrate.

10. A method for measuring the temperature of a substrate, according to claim 9, wherein said photon energy comprises a wavelength range substantially between substantially low ultraviolet to substantially high infrared.

11. A method for measuring the temperature of a substrate, according to claim 10, wherein said range is substantially between 0.2.mu.m and 2.2.mu.m.

12. A method for continuously measuring the temperature of a semiconductor substrate, comprising the steps of:

providing a substrate in a chamber, said substrate comprising a layer, said layer having a reflective surface;
forming a film superjacent said surface;
comparing the reflectivity of said surface prior to forming said film and while said film is forming; and
exposing said surface to radiant energy, said energy having a power level, said power level responsive to said compared reflectivities.

13. A method for continuously measuring the temperature of a semiconductor substrate, according to claim 12, wherein said forming a film comprises the step of:

exposing said substrate to a first gas and said radiant energy in situ.

14. A method for continuously measuring the temperature of a semiconductor substrate according to claim 13, wherein said first gas comprises at least one of N.sub.2, NH.sub.3, O.sub.2, N.sub.2 O, Ar, Ar--H.sub.2, H.sub.2, GeH.sub.4, and a Fluorine based gas.

15. A method for continuously measuring the temperature of a semiconductor substrate, according to claim 14, wherein said radiant energy generates heat substantially within the range of 500.degree. C. to 1250.degree. C.

16. A method for continuously measuring the temperature of a semiconductor substrate, according to claim 15, wherein said substrate is exposed to said first gas for approximately 5 seconds to 60 seconds at a flow rate substantially in the range of 50 sccm to 20,000 sccm.

17. A method for continuously measuring the temperature of a semiconductor substrate, according to claim 12, wherein the reflectivity of said surface prior to said forming is continuously compared with the reflectivity of said surface during said forming until said film is substantially formed.

18. A method for continuously measuring the temperature of a substrate, according to claim 16, further comprising the step of:

substantially cleaning said substrate prior to said forming.

19. A method for continuously measuring the temperature of a semiconductor substrate, according to claim 18, wherein said cleaning comprises introducing a second gas at a temperature substantially within the range of 500.degree. C. to 1250.degree. C. for approximately 10 to 60 seconds, said second gas comprising at least one of: CF.sub.4; C.sub.2 F.sub.2; C.sub.2 F.sub.6; C.sub.4 F.sub.8; CHF.sub.3; HF; NF.sub.3; NF.sub.3 diluted with ar--H.sub.2; and GeH.sub.4, HF, and H.sub.2 diluted with Ar--H.sub.2.

20. A method for externally measuring the continuous temperature of a semiconductor substrate in chamber, comprising the steps of:

providing a substantially clean semiconductor substrate in said chamber, said substrate having a layer superjacent said substrate, said layer having a reflective surface;
forming a film superjacent said surface by introducing a gas and photon energy in situ, said gas comprising at least one of N.sub.2, NH.sub.3, O.sub.2 and N.sub.2 O, said energy generating a temperature substantially within the range of 500.degree. C. to 1250.degree. C., said energy substantially in the absorption band of silicon;
measuring the reflectivity of said surface prior to said forming and continuously during said forming until said film is substantially formed; and
exposing said substrate to said photon energy, said energy having a power level, said power level responsive to the measured reflectivities of said film..Iadd.

21. A method for measuring the temperature of a substrate, comprising:

providing a substrate in a chamber, said substrate having a reflective surface;
exposing said substrate to a gas and radiant energy to form a film over said substrate, said energy having a power level;
controlling said power level responsive to comparing the reflectivity of said surface prior to said exposing to the reflectivity of said surface while said film is being formed..Iaddend..Iadd.22. A method for measuring the temperature of a substrate according to claim 21, wherein said method is performed under substantially high vacuum..Iaddend..Iadd.23. A method for measuring the temperature of a substrate, according to claim 21, wherein said surface comprises a layer formed over said substrate..Iaddend..Iadd.24. A method for measuring the temperature of a substrate, according to claim 23, wherein said layer comprises a masking pattern..Iaddend..Iadd.25. A method for measuring the temperature of a substrate, according to claim 23, wherein said layer is formed by at least one of Chemical Vapor Deposition ("CVD"), Rapid Thermal Processing Chemical Vapor Deposition ("RTPCVD"), Low Pressure Chemical Vapor Deposition ("LPCVD"), Molecular Beam Epitaxy ("MBE"), Reactive Ion Sputtering ("RIS"), Physical Vapor Deposition ("PVC") and Plasma Processing..Iaddend..Iadd.26. A method for measuring the temperature of a substrate, according to claim 23, wherein said layer functions as a barrier layer, said layer comprising

at least one of TiN and TaN..Iaddend..Iadd.27. A method for measuring the temperature of a substrate, according to claim 21, wherein the reflectivity of said surface prior to said exposing is substantially continuously compared with the reflectivity of said surface during said exposing until said film is substantially formed..Iaddend..Iadd.28. A method for measuring the temperature of a substrate, according to claim 21, wherein said substrate comprising at least one of single crystal silicon, polycrystalline silicon and amorphous silicon..Iaddend..Iadd.29. A method for measuring the temperature of a substrate, according to claim 21, wherein said energy comprises photon energy substantially in the absorption band of said substrate..Iaddend..Iadd.30. A method for measuring the temperature of a substrate, according to claim 29, wherein said photon energy comprises a wavelength range substantially between substantially low ultraviolet to substantially high infrared..Iaddend..Iadd.31. A method for measuring the temperature of a substrate, according to claim 30, wherein said range is substantially between 0.2.mu.m and 2.2.mu.m..Iaddend..Iadd.32. A method for measuring the temperature of a semiconductor substrate, comprising:

providing a substrate in a chamber, said substrate comprising a layer, said layer having a reflective surface;
exposing said reflective surface to radiant energy, said energy having a power level;
forming a film over said reflective surface; and
controlling said power level responsive to comparing the reflectivity of said reflective surface prior to forming said film and while said film is

forming..Iaddend..Iadd.33. A method for measuring the temperature of a semiconductor substrate, according to claim 32, wherein said forming a film further comprises exposing said substrate to a first gas and said radiant energy..Iaddend..Iadd.34. A method for measuring the temperature of a semiconductor substrate, according to claim 33, wherein said first gas comprises at least one of N.sub.2, NH.sub.3, O.sub.2, N.sub.2 O, Ar, Ar--H.sub.2, H.sub.2, GeH.sub.4, and a Fluorine based gas..Iaddend..Iadd.35. A method for measuring the temperature of a semiconductor substrate, according to claim 32, wherein said radiant energy generates heat substantially within the range of 500.degree. C. to 1250.degree. C..Iaddend..Iadd.36. A method for measuring the temperature of a semiconductor substrate, according to claim 35, wherein said substrate is exposed to said first gas for approximately 5 seconds to 60 seconds at a flow rate substantially in the range of 50 sccm to 20,000 sccm..Iaddend..Iadd.37. A method for measuring the temperature of a semiconductor substrate, according to claim 32, wherein the reflectivity of said surface prior to said forming is continuously compared with the reflectivity of said surface during said forming until said film is substantially formed..Iaddend..Iadd.38. A method for measuring the temperature of a substrate, according to claim 32, further comprising substantially cleaning said substrate prior to said forming.

.Iaddend..Iadd.39. A method for continuously measuring the temperature of a semiconductor substrate, according to claim 38, wherein said cleaning comprises introducing a second gas at a temperature substantially within the range of 500.degree. C. to 1250.degree. C. for approximately 10 to 60 seconds, said second gas comprising at least one of: CF.sub.4; C.sub.2 F.sub.2; C.sub.2 F.sub.6; C.sub.2 F.sub.8; CHF.sub.3; HF; NF.sub.3; NF.sub.3 diluted with Ar--H.sub.2; and GeH.sub.4, HF, and H.sub.2 diluted with Ar--H.sub.2..Iaddend..Iadd.40. A method for externally measuring the continuous temperature of a semiconductor substrate in a chamber, comprising:

providing a substantially clean semiconductor substrate having a layer over said substrate, said layer having a reflective surface;
forming a film over said layer by exposing said layer to a gas and photon energy, said gas comprising at least one of N.sub.2, NH.sub.3, O.sub.2 and N.sub.2 O, said energy generating a temperature substantially within the range of 500.degree. C. to 1250.degree. C., said energy substantially in the absorption band of silicon;
measuring the reflectivity of said surface prior to said forming and continuously during said forming until said film is substantially formed; and
controlling a power level of said photon energy responsive to said measured reflectivities..Iaddend..Iadd.41. A method for controlling the temperature of a semiconductor substrate having a reflective surface comprising:
exposing the reflective surface to radiant energy, said energy having a power level;
sensing changes in reflectivity of the reflective surface while a layer is formed on the reflective surface; and
controlling said power level in response to said sensed changes in reflectivity..Iaddend..Iadd.42. The method of claim 41, wherein said

method is performed under substantially high vacuum..Iaddend..Iadd.43. The method of claim 41, wherein the reflectivity of said surface prior to said exposing is substantially continuously compared with the reflectivity of said surface during said exposing until said layer is substantially formed..Iaddend..Iadd.44. The method of claim 41, wherein said substrate comprises at least one of single crystal silicon, polycrystalline silicon, and amorphous silicon..Iaddend..Iadd.45. The method of claim 41, wherein said energy comprises photon energy substantially in the absorption band of said substrate..Iaddend..Iadd.46. The method of claim 45, wherein said photon energy comprises a wavelength range substantially between substantially low ultraviolet to substantially high infrared..Iaddend..Iadd.47. The method of claim 30, wherein said range is substantially between 0.2.mu.m and 2.2.mu.m..Iaddend..Iadd.48. A method for controlling the temperature of a semiconductor substrate, comprising:

providing a semiconductor substrate having a reflective surface;
forming a film on said reflective surface by introducing a first gas and photon energy;
measuring the reflectivity of said reflective surface prior to said forming and during said forming until said film is substantially formed; and
controlling a power level of said photon energy in response to said measured reflectivity..Iaddend..Iadd.49. The method of claim 48, wherein said first gas comprises at least one of N.sub.2, NH.sub.3, O.sub.2, N.sub.2 O, Ar, Ar--H.sub.2, H.sub.2, GeH.sub.4, and a Fluorine based gas.

.Iaddend..Iadd.50. The method of claim 48, wherein said radiant energy generates heat substantially within the range of 500.degree. C. to 1250.degree. C..Iaddend..Iadd.51. The method of claim 48, wherein said substrate is exposed to said first as for approximately 5 seconds to 60 seconds at a flow rate substantially in the range of 50 sccm to 20,000 sccm..Iaddend..Iadd.52. The method of claim 48, wherein the reflectivity of said surface prior to said forming is continuously compared with the reflectivity of said surface during said forming until said film is substantially formed..Iaddend..Iadd.53. The method of claim 48, further including substantially cleaning said substrate prior to said forming..Iaddend..Iadd.54. The method of claim 49, wherein said cleaning comprises introducing a second gas at a temperature substantially within the range of 500.degree. C. to 1250.degree. C. for approximately 10 to 60 seconds, said second gas comprising at least one of: CF.sub.4; C.sub.2 F.sub.2; C.sub.2 F.sub.6; C.sub.4 F.sub.8; CHF.sub.3; HF; NF.sub.3; NH.sub.3 diluted with Ar--H2; and GeH.sub.4, HF, and H.sub.2 diluted with Ar--H.sub.2..Iaddend..Iadd.55. A method for controlling the temperature of a semiconductor substrate having a reflective surface, comprising:

forming a film over said surface;
exposing said reflective surface to radiant energy, said energy having a power level;
measuring the reflectivity of said reflective surface prior to forming said film and while said film is forming; and
controlling said power level in response to said measured reflectivities..Iaddend..Iadd.56. The method of claim 55, wherein said forming a film further comprises exposing said substrate to a first gas and said radiant

energy..Iaddend..Iadd.57. The method of claim 56 wherein said first gas comprises at least one of N.sub.2, NH.sub.3, O.sub.2, N.sub.2 O, Ar, Ar--H.sub.2; H.sub.2; GeH.sub.4, and a Fluorine based gas..Iaddend..Iadd.58. The method of claim 55, wherein said radiant energy generates heat substantially within the range of 500.degree. C. to 1250.degree. C..Iaddend..Iadd.59. The method of claim 56, wherein said substrate is exposed to said first gas for approximately 5 seconds to 60 seconds at a flow rate substantially in the range of 50 sccm to 20,000 sccm..Iaddend..Iadd.60. The method of claim 55, wherein the reflectivity of said surface prior to said forming is continuously compared with the reflectivity of said surface during said forming until said film is substantially formed..Iaddend..Iadd.61. The method of claim 55, further comprising substantially cleaning said substrate prior to said forming..Iaddend..Iadd.62. The method of claim 61, wherein said cleaning comprises introducing a second gas at a temperature substantially within the range of 500.degree. C. to 1250.degree. C. for approximately 10 to 60 seconds said second gas comprising at least one of: CF.sub.4; C.sub.2 F.sub.2; C.sub.2 F.sub.6; C.sub.4 F.sub.8; CHF.sub.3; HF; NF.sub.3; NF.sub.3 diluted with Ar--H2; and GeH.sub.4, HF, and H.sub.2 diluted with Ar--H.sub.2..Iaddend.

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Other references
  • F.Y. Sorrell et al. Applied RTP Optical Modeling: An Argument for Open Loop Control, SRC Contract 91-MP-132 SRC PUB C92470, Aug. 1992, pp. 1-8. Tsutomu Sato, Spectral Emissivity of Silicon, Japanese Journal of Applied Physics vol. 6, No. 3, Mar. 1967 pp. 339-347. JM Dihac et al. . . . In Situ Wafer Emmissivity Measurement in a Rapid Thermal Processor, Mat Res. Soc Symp, Proc vol. 224 Materials Research Society, 1991 pp. 3-8. W. A. Barron, The Principals of Infrared Thermometry, Sensors Dec. 1992, pp. 10-19. F. Yates Sorrell et al. . . . Temperature Uniformity in RTP Furnaces, IEEE Transactions on Electron Devices vol. 39 No. 1, Jan. 1992, pp. 75-79.
Patent History
Patent number: RE36050
Type: Grant
Filed: Sep 27, 1996
Date of Patent: Jan 19, 1999
Assignee: Micron Technology, Inc. (Boise, ID)
Inventors: Randhir P. S. Thakur (Boise, ID), Gurtej S. Sandhu (Boise, ID), Annette L. Martin (Boise, ID)
Primary Examiner: G. Bradley Bennett
Law Firm: Trask, Britt & Rossa
Application Number: 8/722,360
Classifications
Current U.S. Class: Change Of Optical Property (374/161); Comparison With Radiation Reference Standard (374/129); Optical Pyrometers (356/43)
International Classification: G01J 554;