Periodic patterns and technique to control misalignment between two layers

• US 8,570,515 B2
• Filed: 11/30/2009
• Issued: 10/29/2013
• Est. Priority Date: 04/10/2001
• Status: Expired due to Fees

• Current Assignee: KLA-Tencor Corporation
• Original Assignee: KLA-Tencor Corporation
• Inventors: Abdulhalim, Ibrahim, Adel, Mike, Friedmann, Michael, Faeyrman, Michael
• Primary Examiner(s): Toatley, Gregory J
• Assistant Examiner(s): Valentin, II, Juan D
• Application Number:
  US12/628,092
• Publication Number:
  US 20100073688A1
• Time in Patent Office: 1,429 Days
• Field of Search: None
• US Class Current: 356/399
• CPC Class Codes: G01B 11/14 for measuring distance or clearance between spaced objects or spaced apertures G01B11/26 takes precedence; rangefinders G01C3/00
• CPC Class Codes: G01B 11/26 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G01N 21/9501 Semiconductor wafers manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• CPC Class Codes: G03F 7/70633 Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14
• CPC Class Codes: H01L 2223/54426 for alignment
• CPC Class Codes: H01L 2223/54453 for use prior to dicing
• CPC Class Codes: H01L 2223/5446 Located in scribe lines
• CPC Class Codes: H01L 23/544 Marks applied to semiconductor devices or parts, e.g. registration marks, alignment structures, wafer maps test patterns for characterising or monitoring manufacturing processes H01L22/00
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A method and system to measure misalignment error between two overlying or interlaced periodic structures are proposed. The overlying or interlaced periodic structures are illuminated by incident radiation, and the diffracted radiation of the incident radiation by the overlying or interlaced periodic structures are detected to provide an output signal. The misalignment between the overlying or interlaced periodic structures may then be determined from the output signal.

Claims

1. A method for detecting misalignment of overlying or interlaced periodic structures having substantially the same pitch, comprising:

illuminating the overlying or interlaced periodic structures having substantially the same pitch with incident radiation;

detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures along two different detection paths to provide at least one output signal, wherein positive first-order diffraction is directed along one of the two different detection paths and negative first-order diffraction is directed along the other one of the two different detection paths; and

determining a misalignment between the structures from the at least one output signal;

said determining comprising calculating a derived signal from the at least one output signal, wherein the derived signal contains information related to polarization angle.

2. The method of claim 1, wherein said determining includes comparing the at least one output signal with reference signal.

3. The method of claim 2, wherein the reference signal comprises a database.

4. The method of claim 1, wherein said determining includes subtracting the intensities of the positive first-order diffraction and negative first-order diffraction to obtain a differential intensity value.

5. The method of claim 1, wherein the positive first-order diffraction and negative first-order diffraction are detected substantially simultaneously.

6. The method of claim 1, wherein the positive first-order diffraction and negative first-order diffraction are detected sequentially.

7. The method of claim 1, wherein the positive first-order diffraction and negative first-order diffraction are detected sequentially or substantially simultaneously, and said determining includes subtracting the intensities of the positive first-order diffraction and negative first-order diffraction to obtain a differential intensity value.

8. The method of claim 7, wherein said determining includes comparing the differential intensity value to a database to determine a misalignment between the structures.

9. The method of claim 1, wherein said determining includes obtaining a difference between phase angles of the positive first-order diffraction and negative first-order diffraction.

10. The method of claim 9, wherein said obtaining includes interfering the positive first-order diffraction and negative first-order diffraction to obtain a differential phase value.

11. The method of claim 10, wherein said determining includes comparing the differential phase value to a database to determine a misalignment between the structures.

12. The method of claim 1, wherein the incident polarization angle of an illumination beam used in the illuminating to produce said positive and negative first order diffractions is monitored.

13. The method of claim 12, wherein a differential intensity is calculated from said positive and negative first order diffractions produced at a selected incident polarization angle of said illumination beam.

14. The method of claim 13, wherein the determining determines the misalignment between the structures from said calculated differential intensity.

15. The method of claim 13, wherein the differential intensity is calculated from said positive and negative first order diffractions at an incident polarization angle of said illumination beam where intensities of the first order diffractions are maximum.

16. The method of claim 1, wherein the detecting detects intensities of the positive first-order diffraction and negative first-order diffraction from the illuminated portions of the overlying or interlaced periodic structures at a plurality of different incident polarization angles of an illumination beam used in the illuminating to produce said positive and negative first order diffractions.

17. An apparatus for detecting misalignment of overlying or interlaced periodic structures, comprising:

a source illuminating the overlying or interlaced periodic structures with incident radiation;

at least one detector detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures along two different detection paths to provide at least one output signal, wherein positive first-order diffraction is directed along one of the two different detection paths and negative first-order diffraction is directed along the other one of the two different detection paths; and

a processor determining a misalignment between the structures from the at least one output signal, wherein the at least one detector detects intensities of the positive first-order diffraction and negative first-order diffraction from the illuminated portions of the overlying or interlaced periodic structures at a plurality of different incident polarization angles, and said processor subtracts the intensities of the positive first-order diffraction and negative first-order diffraction detected at each of said plurality of different incident polarization angles to obtain a corresponding differential intensity value.

18. The apparatus of claim 17, wherein said processor compares the at least one output signal with a reference signal.

19. The apparatus of claim 18, wherein the reference signal comprises a database.

20. The apparatus of claim 17, wherein said processor calculates a derived signal from the at least one output signal.

21. The apparatus of claim 17, wherein the positive first-order diffraction and negative first-order diffraction are detected substantially simultaneously.

22. The apparatus of claim 17, wherein the positive first-order diffraction and negative first-order diffraction are detected sequentially.

23. The apparatus of claim 17, wherein said processor subtracts the intensities of the positive first-order diffraction and negative first-order diffraction to obtain a differential intensity value.

24. The apparatus of claim 23, wherein said processor compares the differential intensity value to a database to determine a misalignment between the structures.

25. The apparatus of claim 17, wherein said processor compares the differential intensity values obtained at said plurality of different incident polarization angles to a database to determine a misalignment between the structures.

26. The apparatus of claim 17, wherein said processor obtains a difference between phase angles of the positive first-order diffraction and negative first-order diffraction.

27. The apparatus of claim 17, wherein the positive first-order diffraction and negative first-order diffraction interfere to provide a differential phase value.

28. The apparatus of claim 27, wherein said processor compares the differential phase value to a database to determine a misalignment between the structures.

29. A method for detecting misalignment of overlying or interlaced periodic structures, comprising:

illuminating the overlying or interlaced periodic structures with incident radiation;

detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures along two different detection paths to provide at least one output signal, wherein positive first-order diffraction is directed along one of the two different detection paths and negative first-order diffraction is directed along the other one of the two different detection paths; and

determining a misalignment between the structures from the at least one output signal wherein the detecting detects intensities of the positive first-order diffraction and negative first-order diffraction from the illuminated portions of the overlying or interlaced periodic structures at a plurality of different incident polarization angles, and said determining includes subtracting the intensities of the positive first-order diffraction and negative first-order diffraction detected at each of said plurality of different incident polarization angles to obtain a corresponding differential intensity value.

30. The method of claim 29, wherein said determining includes comparing the differential intensity values obtained at said plurality of different incident polarization angles to a database to determine a misalignment between the structures.

31. A method for detecting misalignment of overlying or interlaced periodic structures, comprising:

illuminating the overlying or interlaced periodic structures with incident radiation;

detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures along two different detection paths to provide at least one output signal, wherein positive first-order diffraction is directed along one of the two different detection paths and negative first-order diffraction is directed along the other one of the two different detection paths; and

determining a misalignment between the structures from the at least one output signal, wherein said determining includes obtaining a difference between polarization angles of the positive first-order diffraction and negative first-order diffraction.

32. The method of claim 31, wherein said determining includes comparing the difference to a database to determine a misalignment between the structures.

33. An apparatus for detecting misalignment of overlying or interlaced periodic structures, comprising:

a source illuminating the overlying or interlaced periodic structures with incident radiation;

at least one detector detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures along two different detection paths to provide at least one output signal, wherein positive first-order diffraction is directed along one of the two different detection paths and negative first-order diffraction is directed along the other one of the two different detection paths; and

a processor determining a misalignment between the structures from the at least one output signal, said determining including calculating a derived signal from the at least one output signal, wherein the derived signal contains information related to polarization angle.

34. The apparatus of claim 33, wherein the derived signal contains information related to differential intensity, differential phase, or differential polarization angle.

35. The apparatus of claim 33, further comprising a reference radiation detection unit that detects radiation from the source and provides information regarding intensity fluctuation of the source to the processor.

36. The apparatus of claim 35, said processor normalizing said at least one output signal using said information when it determines a misalignment between the structures from the at least one output signal.

37. An apparatus for detecting misalignment of overlying or interlaced periodic structures, comprising:

a source illuminating the overlying or interlaced periodic structures with incident radiation;

at least one detector detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures along two different detection paths to provide at least one output signal, wherein positive first-order diffraction is directed along one of the two different detection paths and negative first-order diffraction is directed along the other one of the two different detection paths; and

a processor determining a misalignment between the structures from the at least one output signal, wherein said processor obtains a difference between polarization angles of the positive first-order diffraction and negative first-order diffraction.

38. The apparatus of claim 37, wherein said processor compares the difference to a database to determine a misalignment between the structures.

39. An apparatus for detecting misalignment of overlying or interlaced periodic structures, comprising:

a source illuminating the overlying or interlaced periodic structures with incident radiation along an illumination path;

a polarizer in said illumination path to polarize the incident radiation before it reaches the overlying or interlaced periodic structures;

at least one detector detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures along two different detection paths to provide at least one output signal, wherein positive first-order diffraction is directed along one of the two different detection paths and negative first-order diffraction is directed along the other one of the two different detection paths; and

a processor determining a misalignment between the structures from the at least one output signal.

40. The apparatus of claim 39, wherein each of the detection paths includes an analyzer.

41. The apparatus of claim 40, wherein said polarizer is rotated and the analyzers are fixed in positions when the at least one detector is detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures.

42. The apparatus of claim 40, wherein said analyzers are rotated and the polarizer is fixed in position when the at least one detector is detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures.

43. The apparatus of claim 39, wherein the at least one detector detects intensities of the positive first-order diffraction and negative first-order diffraction from the illuminated portions of the overlying or interlaced periodic structures at a plurality of different incident polarization angles, and said processor subtracts the intensities of the positive first-order diffraction and negative first-order diffraction.

44. The apparatus of claim 39, further comprising a reference radiation detection unit that detects radiation from the source and provides information regarding intensity fluctuation of the source to the processor.

45. The apparatus of claim 44, said processor normalizing said at least one output signal using said information.

46. A method for detecting misalignment of overlying or interlaced periodic structures, comprising:

illuminating the overlying or interlaced periodic structures in an illumination path with incident radiation;

detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures along two different detection paths to provide at least one output signal, wherein positive first-order diffraction is directed along one of the two different detection paths and negative first-order diffraction is directed along the other one of the two different detection paths, wherein radiation in the illumination or detection paths is polarized and said illuminating and detecting are performed at different polarization angles to provide a plurality of output signals; and

determining a misalignment between the structures from the plurality of output signals.

47. The method of claim 46, wherein said illuminating illuminates by means of a polarized illumination beam at an incident polarization angle.

48. The method of claim 46, further comprising selecting from said different polarization angles a particular polarization angle.

49. The method of claim 48, wherein said determining includes calculating a differential intensity from the output signal provided by said illuminating and detecting when performed at said particular polarization angle.

50. The method of claim 48, wherein the polarization angle at which the intensity of the diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures is a maximum is selected as said particular polarization angle.

51. The method of claim 46, wherein the incident radiation is polarized.

52. An apparatus for detecting misalignment of overlying or interlaced periodic structures having substantially the same pitch, comprising:

a source illuminating the overlying or interlaced periodic structures having substantially the same pitch in an illumination path with incident radiation;

at least one detector detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures along two different detection paths to provide at least one output signal, wherein positive first-order diffraction is directed along one of the two different detection paths and negative first-order diffraction is directed along the other one of the two different detection paths;

an instrument causing an alteration of a polarization angle of radiation in the illumination or detection paths so that the at least one detector provides a plurality of output signals corresponding to different polarization angles of radiation in the illumination or detection paths;

a processor processing the plurality of output signals provided by said at least one detector to determine a misalignment between the structures.

53. The apparatus of claim 52, wherein said instrument includes a polarizer in the illumination path, and an analyzer in each of the detection paths.

54. The apparatus of claim 53, wherein said instrument includes a device, and said polarizer is rotated by the device and the analyzers are fixed in positions when the at least one detector is detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures.

55. The apparatus of claim 53, wherein said instrument includes a device, and said analyzers are rotated and the polarizer is fixed in position when the at least one detector is detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures.

56. The apparatus of claim 52, wherein the at least one detector detects intensities of the positive first-order diffraction and negative first-order diffraction from the illuminated portions of the overlying or interlaced periodic structures at said plurality of different polarization angles, and said processor subtracts the intensities of the positive first-order diffraction and negative first-order diffraction.

57. An apparatus for detecting misalignment of overlying or interlaced periodic structures, comprising:

a source illuminating the overlying or interlaced periodic structures with incident radiation;

at least one detector detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures along two different detection paths to provide output signals, wherein positive first-order diffraction is directed along one of the two different detection paths and negative first-order diffraction is directed along the other one of the two different detection paths; and

a processor calculating a derived signal from the output signals and determining a misalignment between the structures from said derived signal, said derived signal containing information related to polarization of the output signals.

58. The apparatus of claim 57, wherein the derived signal contains information related to polarization angle.

59. A method for detecting misalignment of overlying or interlaced periodic structures having substantially the same pitch, comprising:

illuminating the overlying or interlaced periodic structures with incident polarized radiation;

detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures along two different detection paths to provide output signals, wherein positive first-order diffraction is directed along one of the two different detection paths and negative first-order diffraction is directed along the other one of the two different detection paths; and

calculating a derived signal from the output signals and determining a misalignment between the structures from said derived signal, said derived signal containing information related to polarization of the output signals.

60. The method of claim 59, wherein the derived signal contains information related to polarization angle.

61. A method for detecting misalignment of overlying or interlaced periodic structures having substantially the same pitch, comprising:

illuminating the overlying or interlaced periodic structures having substantially the same pitch with incident radiation;

detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures along two different detection paths to provide at least one output signal, wherein positive first-order diffraction is directed along one of the two different detection paths and negative first-order diffraction is directed along the other one of the two different detection paths; and

determining a misalignment between the structures from the at least one output signal, said determining including calculating a derived signal from the at least one output signal, wherein the derived signal contains information related to differential polarization angle.