Multi-technique thin film analysis tool

• US 6,816,570 B2
• Filed: 03/07/2002
• Issued: 11/09/2004
• Est. Priority Date: 03/07/2002
• Status: Active Grant

• Current Assignee: KLA-Tencor Corporation
• Original Assignee: KLA-Tencor Corporation
• Inventors: Janik, Gary R., Moore, Jeffrey
• Primary Examiner(s): Church, Craig E.
• Assistant Examiner(s): Kiknadze, Irakli
• Application Number:
  US10/094,537
• Publication Number:
  US 20030169846A1
• Time in Patent Office: 978 Days
• Field of Search: 378/50, 378/89, 378/98.8, 378/42, 378/54, 250/310
• US Class Current: 378/50
• CPC Class Codes: G01B 15/02 for measuring thickness
• CPC Class Codes: G01N 23/20 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials

Abstract

A thin film analysis system includes multi-technique analysis capability. Grazing incidence x-ray reflectometry (GXR) can be combined with x-ray fluorescence (XRF) using wavelength-dispersive x-ray spectrometry (WDX) detectors to obtain accurate thickness measurements with GXR and high-resolution composition measurements with XRF using WDX detectors. A single x-ray beam can simultaneously provide the reflected x-rays for GXR and excite the thin film to generate characteristic x-rays for XRF. XRF can be combined with electron microprobe analysis (EMP), enabling XRF for thicker films while allowing the use of the faster EMP for thinner films. The same x-ray detector(s) can be used for both XRF and EMP to minimize component count. EMP can be combined with GXR to obtain rapid composition analysis and accurate thickness measurements, with the two techniques performed simultaneously to maximize throughput.

Claims

1. A thin film analysis system for analyzing a sample coating, the thin film analysis system comprising:

a microfocus x-ray tube for generating a source x-ray beam;

an x-ray beam focusing system for focusing the source x-ray beam onto the sample coating to cause the sample coating to emit a first set of characteristic x-rays;

an electron beam (e-beam) generator for directing an e-beam at the sample coating to cause the sample coating to emit a second set of characteristic x-rays; and

a first x-ray detector for measuring a first portion of the first set of characteristic x-rays and a first portion of the second set of characteristic x-rays.

2. The thin film analysis system of claim 1, wherein the x-ray beam focusing system comprises an x-ray reflector.

3. The thin film analysis system of claim 2, wherein the x-ray reflector comprises a doubly curved crystal.

4. The thin film analysis system of claim 2, wherein the x-ray reflector comprises a monochromator.

5. The thin film analysis system of claim 1, wherein the x-ray beam focusing system comprises a polycapillary array.

6. The thin film analysis system of claim 1, wherein the first x-ray detector comprises an energy-dispersive x-ray spectrometer.

7. The thin film analysis system of claim 1, wherein the first x-ray detector comprises a wavelength-dispersive x-ray spectrometer.

8. The thin film analysis system of claim 1, further comprising a second x-ray detector, the second x-ray detector being configured to measure a second portion of the first set of characteristic x-rays and a second portion of the second set of characteristic x-rays,

wherein each of the first portion of the first set of characteristic x-rays has a first wavelength, wherein each of the second portion of the first set of characteristic x-rays has a second wavelength, and wherein the first wavelength is different from the second wavelength, and

wherein each of the first portion of the second set of characteristic x-rays has a third wavelength, wherein each of the second portion of the second set of characteristic x-rays has a fourth wavelength, and wherein the third wavelength is different from the fourth wavelength.

9. The thin film analysis system of claim 8, wherein the first x-ray detector and the second x-ray detector comprise wavelength-dispersive spectrometers, the first x-ray detector being configured to measure copper Cu-K x-rays, and the second x-ray detector being configured to measure tantalum Ta-L x-rays.

10. The thin film analysis system of claim 8, wherein the first x-ray detector and the second x-ray detector comprise wavelength-dispersive spectrometers, the first x-ray detector being configured to measure copper Cu-K x-rays, and the second x-ray detector being configured to measure titanium Ti-K x-rays.

11. The thin film analysis system of claim 1, the e-beam generator being able to set the e-beam energy between 5 keV and 35 keV.

12. The thin film analysis system of claim 1, the microfocus x-ray tube being configured to generate molybdenum Mo-K x-rays.

13. The thin film analysis system of claim 1, wherein the first x-ray detector comprises a wavelength-dispersive spectrometer, the first x-ray detector being configured to measure nitrogen-N K x-rays.

14. A thin film analysis system for analyzing a sample coating, the thin film analysis system comprising:

a first microfocus x-ray tube for generating a first source x-ray beam;

a position-sensitive detector;

a first x-ray beam focusing system for focusing the first source x-ray beam onto the sample coating, the first source x-ray beam being configured such that a first portion of the first source x-ray beam is reflected onto the position-sensitive detector by the sample coating;

an electron beam (e-beam) generator for directing an e-beam at the sample coating to cause the sample coating to emit a first set of characteristic x-rays; and

a first x-ray detector, the first x-ray detector being configured to measure a first portion of the first set of characteristic x-rays.

15. The thin film analysis system of claim 14, wherein the first x-ray beam focusing system comprises an x-ray reflector.

16. The thin film analysis system of claim 15, wherein the x-ray reflector comprises a doubly curved crystal.

17. The thin film analysis system of claim 15, wherein the x-ray reflector comprises a monochromator.

18. The thin film analysis system of claim 14, wherein the first source x-ray beam consists of x-rays having the same wavelength, and wherein the first x-ray beam focusing system comprises a polycapillary array.

19. The thin film analysis system of claim 14, wherein the first x-ray detector comprises an energy-dispersive x-ray spectrometer.

20. The thin film analysis system of claim 14, wherein the first x-ray detector comprises a wavelength-dispersive x-ray spectrometer.

21. The thin film analysis system of claim 14, further comprising a second x-ray detector, the second x-ray detector being configured to measure a second portion of the set of characteristic x-rays, each of the first portion of the first set of characteristic x-rays having a first wavelength, and each of the second portion of the first set of characteristic x-rays having a second wavelength, the first wavelength being different from the second wavelength.

22. The thin film analysis system of claim 21, wherein the first x-ray detector and the second x-ray detector comprise wavelength-dispersive spectrometers, the first x-ray detector being configured to measure copper Cu-K x-rays, and the second x-ray detector being configured to measure tantalum Ta-L x-rays.

23. The thin film analysis system of claim 21, wherein the first x-ray detector and the second x-ray detector comprise wavelength-dispersive spectrometers, the first x-ray detector being configured to measure copper Cu-K x-rays, and the second x-ray detector being configured to measure titanium Ti-K x-rays.

24. The thin film analysis system of claim 14, the e-beam generator being able to set the e-beam energy between 5 KeV and 35 KeV.

25. The thin film analysis system of claim 14, wherein the first x-ray detector comprises a wavelength-dispersive spectrometer, the first x-ray detector being configured to measure nitrogen N-K x-rays.

26. The thin film analysis system of claim 14, wherein the microfocus x-ray tube, the position-sensitive detector, the e-beam generator, and the first x-ray detector can operate simultaneously.

27. The thin film analysis system of claim 14, wherein a measurement of the first portion of the first source x-ray beam by the position-sensitive detector and a measurement of the first portion of the first set of characteristic x-rays by the first x-ray detector can be performed in rapid succession with each other.

28. The thin film analysis system of claim 14, the first source x-ray beam being further configured such that a second portion of the first source x-ray beam is absorbed by the sample coating to cause the sample coating to emit a second set of characteristic x-rays, the first x-ray detector being configured to measure a first portion of the second set of characteristic x-rays.

29. The thin film analysis system of claim 28, wherein the x-ray beam focusing system comprises an x-ray reflector.

30. The thin film analysis system of claim 29, wherein the x-ray reflector comprises a doubly curved crystal.

31. The thin film analysis system of claim 29, wherein the x-ray reflector comprises a monochromator.

32. The thin film analysis system of claim 28, wherein the first source x-ray beam consists of x-rays having the same wavelength, and wherein the first x-ray beam focusing system comprises a polycapillary array.

33. The thin film analysis system of claim 28, wherein the first x-ray detector comprises an energy-dispersive x-ray spectrometer.

34. The thin film analysis system of claim 28, wherein the first x-ray detector comprises a wavelength-dispersive x-ray spectrometer.

35. The thin film analysis system of claim 28, further comprising a second x-ray detector, the second x-ray detector being configured to measure a second portion of the first set of characteristic x-rays and a second portion of the second set of characteristic x-rays,

each of the first portion of the first set of characteristic x-rays having a first wavelength, and each of the second portion of the first set of characteristic x-rays having a second wavelength, the first wavelength being different from the second wavelength, and

each of the first portion of the second set of characteristic x-rays having a third wavelength, and each of the second portion of the second set of characteristic x-rays having a fourth wavelength, the third wavelength being different from the fourth wavelength.

36. The thin film analysis system of claim 28, the first x-ray detector being configured to measure the first portion of the second set of characteristic x-rays at the same time that the position-sensitive detector measures an interference pattern formed by the first portion of the first source x-ray beam after being reflected by the sample coating.

37. The thin film analysis system of claim 28, wherein a measurement of the first portion of the first source x-ray beam by the position-sensitive detector, a measurement of the first portion of the first set of characteristic x-rays by the first x-ray detector, and a measurement of the first portion of the second set of characteristic x-rays by the first x-ray detector can be performed in rapid succession with one another.

38. The thin film analysis system of claim 28, further comprising:

a second microfocus x-ray tube for generating a second source x-ray beam; and

a second x-ray beam focusing system for focusing the second source x-ray beam onto the sample coating, the second source x-ray beam onto the sample coating, the second source x-ray beam being configured such that a first portion of the second source x-ray beam is absorbed by the sample coating to cause the sample coating to emit a second set of characteristic x-rays, the first x-ray detector being configured to measure a first portion of the second set of characteristic x-rays.

39. A method for analyzing sample coatings, the method comprising:

focusing a source x-ray beam onto a first coating of a sample to cause the first coating, to emit a first set of characteristic x-rays;

measuring a first portion of the first set of characteristic x-rays using a first x-ray detector;

directing an electron beam (e-beam) at a second coating of the same sample to cause the second coating, to emit a second set of characteristic x-rays; and

measuring a first portion of the second set of characteristic x-rays using the first x-ray detector.

40. The method of claim 39, wherein the first x-ray detector comprises an energy-dispersive x-ray spectrometer.

41. The method of claim 39, wherein the first x-ray detector comprises a wavelength-dispersive x-ray spectrometer.

42. The method of claim 39, further comprising:

measuring a second portion of the first set of characteristic x-rays using a second x-ray detector, wherein each of the first portion of the first set of characteristic x-rays has a first wavelength, wherein each of the second portion of the first set of characteristic x-rays has a second wavelength, and wherein the first wavelength is different from the second wavelength; and

measuring a second portion of the second set of characteristic x-rays using the second x-ray detector, wherein each of the first portion of the second set of characteristic x-rays has a third wavelength, wherein each of the second portion of the second set of characteristic x-rays has a fourth wavelength, and wherein the third wavelength is different from the fourth wavelength.

43. A thin film analysis system for analyzing a sample coating, the thin film analysis system comprising:

means for generating a source x-ray beam;

means for focusing the source x-ray beam onto the sample coating to cause the sample coating to emit a first set of characteristic x-rays;

means for directing an electron beam (e-beam) at the sample coating to cause the sample coating to emit a second set of characteristic x-rays; and

means for measuring a first portion of the first set of characteristic x-rays and a first portion of the second set of characteristic x-rays.

44. The thin film analysis system of claim 43, wherein the means for focusing the source x-ray beam onto the sample coating comprises an x-ray reflector.

45. The thin film analysis system of claim 44, wherein the x-ray reflector comprises a doubly curved crystal.

46. The thin film analysis system of claim 44, wherein the x-ray reflector comprises a monochromator.

47. The thin film analysis system of claim 43, wherein the means for focusing the source x-ray beam onto the sample coating comprises a polycapillary array.

48. The thin film analysis system of claim 43, wherein the means for measuring comprises an energy-dispersive x-ray spectrometer.

49. The thin film analysis system of claim 43, wherein the means for measuring comprises a wavelength-dispersive x-ray spectrometer.

50. The thin film analysis system of claim 43, further comprising means for measuring a second portion of the first set of characteristic x-rays and a second portion of the second set of characteristic x-rays,

wherein each of the first portion of the first set of characteristic x-rays has a first wavelength, wherein each of the second portion of the first set of characteristic x-rays has a second wavelength, and wherein the first wavelength is different from the second wavelength, and

wherein each of the first portion of the second set of characteristic x-rays has a third wavelength, wherein each of the second portion of the second set of characteristic x-rays has a fourth wavelength, and wherein the third wavelength is different from the fourth wavelength.

51. A thin film analysis system for analyzing a sample coating, the thin film analysis system comprising:

means for generating a first source x-ray beam;

means for focusing the first source x-ray beam onto the sample coating, the first source x-ray beam being configured such that a first portion of the first source x-ray beam is reflected by the sample coating;

means for resolving an interference pattern created by the first portion of the first source x-ray beam after being reflected by the sample coating;

means for directing an electron beam (e-beam) at the sample coating to cause the sample coating to emit a first set of characteristic x-rays; and

means for measuring a first portion of the first set of characteristic x-rays.

52. The thin film analysis system of claim 51, wherein the means for focusing the first source x-ray beam comprises an x-ray reflector.

53. The thin film analysis system of claim 52, wherein the x-ray reflector comprises a doubly curved crystal.

54. The thin film analysis system of claim 52, wherein the x-ray reflector comprises a monochromator.

55. The thin film analysis system of claim 52, wherein the first source x-ray beam consists of x-rays having the same wavelength, and wherein the means for focusing the first source x-ray beam comprises a polycapillary array.

56. The thin film analysis system of claim 52, wherein the means for measuring comprises an energy-dispersive x-ray spectrometer.

57. The thin film analysis system of claim 51, wherein the means for measuring comprises a wavelength-dispersive x-ray spectrometer.

58. The thin film analysis system of claim 51, further comprising means for measuring a second portion of the set of characteristic x-rays, wherein each of the first portion of the first set of characteristic x-rays has a first wavelength, wherein each of the second portion of the first set of characteristic x-rays has a second wavelength, and wherein the first wavelength is different from the second wavelength.

59. The thin film analysis system of claim 51, wherein the means for resolving the interference pattern and the means for measuring the first portion of the first set of characteristic x-rays operate at the same time.

60. The thin film analysis system of claim 51, wherein the means for resolving the interference pattern and the means for measuring the first portion of the first set of characteristic x-rays operate in rapid succession with each other.

61. The thin film analysis system of claim 51, the first source x-ray beam being further configured such that a second portion of the first source x-ray beam is absorbed by the sample coating to cause the sample coating to emit a second set of characteristic x-rays, the thin film analysis system further comprising means for measuring a first portion of the second set of characteristic x-rays.

62. The thin film analysis system of claim 61, wherein the means for focusing the first source x-ray beam comprises an x-ray reflector.

63. The thin film analysis system of claim 62, wherein the x-ray reflector comprises a doubly curved crystal.

64. The thin film analysis system of claim 62, wherein the x-ray reflector comprises a monochromator.

65. The thin film analysis system of claim 61, wherein the first source x-ray beam consists of x-rays having the same wavelength, and wherein the means for focusing the first source x-ray beam comprises a polycapillary array.

66. The thin film analysis system of claim 61, wherein the means for measuring the first portion of the first set of characteristic x-rays comprises an energy-dispersive x-ray spectrometer.

67. The thin film analysis system of claim 61, wherein the means for measuring the first portion of the first set of characteristic x-rays comprises a wavelength-dispersive x-ray spectrometer.

68. The thin film analysis system of claim 61, further comprising means for measuring a second portion of the first set of characteristic x-rays and a second portion of the second set of characteristic x-rays,

wherein each of the first portion of the first set of characteristic x-rays has a first wavelength, wherein each of the second portion of the first set of characteristic x-rays has a second wavelength, and wherein the first wavelength is different from the second wavelength, and

wherein each of the first portion of the second set of characteristic x-rays has a third wavelength, wherein each of the second portion of the second set of characteristic x-rays has a forth wavelength, and wherein the third wavelength is different from the fourth wavelength.

69. The thin film analysis system of claim 61, wherein the means for resolving the interference pattern and the means for measuring the first portion of the second set of characteristic x-rays operate at the same time.

70. The thin film analysis system of claim 61, wherein the means for resolving the interference pattern and the means for measuring the first portion of the second set of characteristic x-rays operate in rapid succession with each other.