INTERFACE, A METHOD FOR OBSERVING AN OBJECT WITHIN A NON-VACUUM ENVIRONMENT AND A SCANNING ELECTRON MICROSCOPE

• US 20100140470A1
• Filed: 10/23/2007
• Published: 06/10/2010
• Est. Priority Date: 10/24/2006
• Status: Active Grant

• Current Assignee: B-nano LTD
• Original Assignee: Dov Shachal
• Inventors: Shachal, Dov
• Granted Patent: US 8,164,057 B2
• Time in Patent Office: Days
• US Class Current: 250/307
• CPC Class Codes: H01J 2237/006 Details of gas supplies, e.g. in an ion source, to a beam line, to a specimen or to a workpiece, H01J37/3244 takes precedence; environmental cells for electron microscopes H01J2237/2003; microscopes with environmental specimen chamber H01J2237/2608
• CPC Class Codes: H01J 2237/0458 movable, i.e. for changing between differently sized apertures
• CPC Class Codes: H01J 2237/15 Means for deflecting or directing discharge
• CPC Class Codes: H01J 2237/164 Particle-permeable windows
• CPC Class Codes: H01J 2237/182 Obtaining or maintaining desired pressure
• CPC Class Codes: H01J 2237/2002 Controlling environment of sample
• CPC Class Codes: H01J 2237/2006 Vacuum seals
• CPC Class Codes: H01J 2237/2605 operating at elevated pressures, e.g. atmosphere
• CPC Class Codes: H01J 2237/28 Scanning microscopes
• CPC Class Codes: H01J 2237/2801 Details
• CPC Class Codes: H01J 2237/2806 Secondary charged particle
• CPC Class Codes: H01J 2237/2807 X-rays
• CPC Class Codes: H01J 37/06 Electron sources; Electron guns electron sources in general H01J1/02, H01J19/02; electron guns in general H01J3/02
• CPC Class Codes: H01J 37/20 Means for supporting or positioning the objects or the material; Means for adjusting diaphragms or lenses associated with the support introducing the objects H01J37/18
• CPC Class Codes: H01J 37/28 with scanning beams H01J37/268, H01J37/292, H01J37/2955 take precedence
• CPC Class Codes: H01J 37/285 Emission microscopes, e.g. field-emission microscopes
• CPC Class Codes: H01J 37/301 Arrangements enabling beams to pass between regions of different pressure

Abstract

An interface, a scanning electron microscope and a method for observing an object that is positioned in a non-vacuum environment. The method includes: passing at least one electron beam that is generated in a vacuum environment through at least one aperture out of an aperture array and through at least one ultra thin membrane that seals the at least one aperture; wherein the at least one electron beam is directed towards the object; wherein the at least one ultra thin membrane withstands a pressure difference between the vacuum environment and the non-vacuum environment; and detecting particles generated in response to an interaction between the at least one electron beam and the object.

Claims

1. A method for observing an object that is positioned in a non-vacuum environment, the method comprises:

passing at least one electron beam that is generated in a vacuum environment through at least one aperture out of an aperture array and through at least one ultra thin membrane that seals the at least one aperture;

wherein the at least one electron beam is directed towards the object;

wherein the at least one ultra thin membrane withstands a pressure difference between the vacuum environment and the non-vacuum environment; and

detecting particles generated in response to an interaction between the at least one electron beam and the object.

2. The method according to claim 1 wherein the passing comprises passing at least one electron beam through multiple apertures of the aperture array.

3. The method according to claim 1 wherein the passing is preceded by selecting an aperture of the aperture array and wherein the passing comprises passing an electron beam through the selected aperture.

4. The method according to claim 1 comprising passing at least one electron beam through at least one aperture of the aperture array wherein apertures of the aperture array are positioned at a single horizontal plain.

5. The method according to claim 1 comprising passing at least one electron beam through at least one aperture of the aperture array;

and

wherein at least one aperture of the aperture array is positioned at a different height than at least one other aperture of the aperture array.

6. The method according to claim 1 comprising passing at least one electron beam through at least one aperture of the aperture array;

and

wherein at least one aperture of the aperture array enables an acquisition of a higher resolution image than at least one other aperture of the aperture array.

7. The method according to claim 1 comprising performing a first iteration of passing and detecting and a second iteration of passing and detecting;

wherein the first phase comprises passing at least one electron beam through at least one aperture to provide a first resolution image of at least a portion of the object, and

the second phase comprises passing at least one electron beam through at least one other aperture to provide a second resolution image of at least a portion of the object.

8. The method according to claim 1 wherein the passing is preceded by locating a region of interest of the object using a low resolution imaging process;

and the passing comprises passing at least one electron beam directed towards the region of interest.

9. The method according to claim 1 wherein the passing and detecting are characterized by a first resolution range and wherein the method further comprises utilizing another observation process that is characterized by a different resolution range.

10. The method according to claim 9 wherein the other observation process comprises atomic force microscopy.

11. The method according to claim 9 wherein the other observation process comprises an optical inspection process.

12. The method according to claim 1 further comprising scanning at least one area of the object by deflecting the at least one electron beam and introducing a corresponding mechanical movement of the at least one aperture through which the at least one electron beam pass.

13. The method according to claim 1 further comprising scanning at least one area of the object by deflecting the at least one electron beam and introducing a corresponding mechanical movement of the aperture array.

14. The method according to claim 1 further comprising scanning at least one area of the object by deflecting the at least one electron beam and introducing a corresponding mechanical movement of the aperture array;

wherein a component that comprises is flexibly coupled to another component of an interface that separates the vacuum environment from the non-vacuum environment.

15. The method according to claim 1 further comprising scanning multiple areas of the object by deflecting the at least one electron beam that pass through multiple apertures of the aperture array.

16. The method according to claim 1 further comprising scanning multiple areas of the object by deflecting the at least one electron beam that pass through multiple apertures of the aperture array and introducing a corresponding mechanical movement of the aperture array.

17. The method according to claim 1 further comprising scanning an area of the object by deflecting the at least one electron beam by a deflector positioned within the vacuum environment.

18. The method according to claim 1 comprising detecting electrons generated in response to the interaction between the at least one electron beam and the object.

19. The method according to claim 1 comprising detecting photons generated in response to the interaction between the at least one electron beam and the object.

20. The method according to claim 1 comprising detecting X-ray emission generated in response to the interaction between the at least one electron beam and the object.

21. The method according to claim 1 comprising detecting particles by a detector positioned within the vacuum environment.

22. The method according to claim 1 comprising detecting particles by a detector positioned within the non-vacuum environment.

23. The method according to claim 1 wherein an optical axis of the at least one electron beam is non-perpendicular to the object.

24. The method according to claim 1 comprising detecting electron current generated as a result of the interaction.

25. The method according to claim 1 comprising detecting Cathodoluminescence of the object, fluorescence markers or light emitted due to electron excitation of gas molecules.

26. The method according to claim 1 further comprising introducing a gas mixture into the non-vacuum environment such as to improve the detecting.

27. The method according to claim 1 further comprising introducing nitrogen into the non-vacuum environment.

28. The method according to claim 1 further comprising introducing He enriched mixture into the non-vacuum environment.

29. The method according to claim 1 further comprising aligning the at least one electron beam with at least one aperture.

30. The method according to claim 1 further comprising aligning the at least one electron beam with at least one aperture by introducing a mechanical moving the at least one aperture.

31. The method according to claim 1 comprising repetitively altering a distance between an aperture and the object and measuring electrons emitted from the object to provide measurements results and comparing the measurement results to a calibration curve that is responsive to a mean free path of electrons in the non-vacuum environment.

32. The method according to claim 1 comprising determining a distance between an aperture and the object based upon an expected mean free path of electrons in the non-vacuum environment.

33. The method according to claim 1 comprising determining a distance between an aperture and the object based upon counts of emitted X-ray photons of gas within the non-vacuum environment that is situated between the object and the aperture.

34. A method for observing an object that is positioned in a non-vacuum environment, the method comprises:

scanning at least one area of the object by;

deflecting at least one electron beam generated in a vacuum environment and allowing the at least one electron beam to pass through at least one aperture sealed by an ultra thin membrane;

wherein the at least one ultra thin membrane withstands a pressure difference between the vacuum environment and the non-vacuum environment; and

introducing a corresponding mechanical movement of the at least one aperture; and

detecting particles generated in response to an interaction between the at least one electron beam and the at least one area of the object.

35. An interface between a vacuum environment and a non-vacuum environment, the interface comprises a aperture array sealed by at least one ultra thin membrane that is substantially transparent to electrons and withstands a pressure difference between the vacuum environment and the non-vacuum environment.

36. The interface according to claim 35 wherein apertures of the aperture array are positioned at a single horizontal plain.

37. The interface according to claim 35 wherein at least one aperture of the aperture array is positioned at a different height than at least one other aperture of the aperture array.

38. The interface according to claim 35 wherein at least one aperture of the aperture array enables an acquisition of a higher resolution image than at least one other aperture of the aperture array.

39. A scanning electron microscope comprising:

an electron beam source positioned in a vacuum environment;

the electron beam source is adapted to generate at least one electron beam;

an interface between the vacuum environment and a non-vacuum environment in which an object is positioned, the interface comprises an aperture array sealed by at least one ultra thin membrane that is substantially transparent to electrons and withstands a pressure difference between the vacuum environment and the non-vacuum environment;

electron optics adapted to direct the at least one electron beam through at least one aperture and towards an object located in the non-vacuum environment; and

a detector that detects particles generated in response to an interaction between the at least one electron beam and the object.

40. The scanning electron microscope according to claim 39 wherein the electron optics directs at least one electron beam towards multiple apertures of the aperture array.

41. The scanning electron microscope according to claim 39 adapted to select an aperture of the aperture array and wherein then direct an electron beam through the selected aperture.

42. The scanning electron microscope according to claim 39 wherein apertures of the aperture array are positioned at a single horizontal plain.

43. The scanning electron microscope according to claim 39 wherein at least one aperture of the aperture array is positioned at a different height than at least one other aperture of the aperture array.

44. The scanning electron microscope according to claim 39 wherein at least one aperture of the aperture array enables an acquisition of a higher resolution image than at least one other aperture of the aperture array.

45. The scanning electron microscope according to claim 39 adapted to direct at least one electron beam through at least one aperture to provide a first resolution image of at least a portion of the object, and then direct at least one electron beam through at least one other aperture to provide a second resolution image of at least a portion of the object.

46. The scanning electron microscope according to claim 39 adapted to locate a region of interest of the object using a low resolution imaging process and then direct at least one electron beam towards the region of interest.

47. The scanning electron microscope according to claim 39 further comprising another observation tool that is characterized by another resolution that the resolution provided by the electron beam.

48. The scanning electron microscope according to claim 47 wherein the other observation tool is an atomic force microscope.

49. The scanning electron microscope according to claim 47 wherein the other observation tool is an optical inspection tool.

50. The scanning electron microscope according to claim 39 adapted to scan at least one area of the object by deflecting the at least one electron beam and introducing a corresponding mechanical movement of the at least one aperture through which the at least one electron beam pass.

51. The scanning electron microscope according to claim 39 adapted to scan at least one area of the object by deflecting the at least one electron beam and introduce a corresponding mechanical movement of the aperture array.

52. The scanning electron microscope according to claim 39 adapted to scan at least one area of the object by deflecting the at least one electron beam and introduce a corresponding mechanical movement of the aperture array;

wherein a component that comprises the aperture array is flexibly coupled to another component of an interface that separates the vacuum environment from the non-vacuum environment.

53. The scanning electron microscope according to claim 39 adapted to scan multiple areas of the object by deflecting the at least one electron beam that pass through multiple apertures of the aperture array.

54. The scanning electron microscope according to claim 39 adapted to scan multiple areas of the object by deflecting the at least one electron beam that pass through multiple apertures of the aperture array and introducing a corresponding mechanical movement of the aperture array.

55. The scanning electron microscope according to claim 39 comprising a deflector positioned within the vacuum environment that deflects the at least one electron beam such as to scan an area of the object.

56. The scanning electron microscope according to claim 39 wherein the detector detects electrons generated in response to the interaction between the at least one electron beam and the object.

57. The scanning electron microscope according to claim 39 wherein the detector detects photons generated in response to the interaction between the at least one electron beam and the object.

58. The scanning electron microscope according to claim 39 wherein the detector detects X-ray emission generated in response to the interaction between the at least one electron beam and the object.

59. The scanning electron microscope according to claim 39 wherein the detector is positioned within the vacuum environment.

60. The scanning electron microscope according to claim 39 wherein the detector is positioned within the non-vacuum environment.

61. The scanning electron microscope according to claim 39 wherein an optical axis of the at least one electron beam is non-perpendicular to the object.

62. The scanning electron microscope according to claim 39 wherein the detector detects electron current generated as a result of the interaction.

63. The scanning electron microscope according to claim 39 wherein the detector detects Cathodoluminescence of the object, fluorescence markers or light emitted due to electron excitation of gas molecules.

64. The scanning electron microscope according to claim 39 adapted to introduce a gas mixture into the non-vacuum environment such as to improve the detecting.

65. The scanning electron microscope according to claim 39 adapted to introduce nitrogen into the non-vacuum environment.

66. The scanning electron microscope according to claim 39 adapted to introduce He enriched mixture into the non-vacuum environment.

67. The scanning electron microscope according to claim 39 adapted to align the at least one electron beam with at least one aperture.

68. The scanning electron microscope according to claim 39 adapted to align the at least one electron beam with at least one aperture by introducing a mechanical movement the at least one aperture.

69. The scanning electron microscope according to claim 39 adapted to repetitively alter a distance between an aperture and the object, measure electrons emitted from the object to provide measurements results and compare the measurement results to a calibration curve that is responsive to a mean free path of electrons in the non-vacuum environment.

70. The scanning electron microscope according to claim 39 adapted to determine a distance between an aperture and the object based upon an expected mean free path of electrons in the non-vacuum environment.

71. The scanning electron microscope according to claim 39 adapted to determine a distance between an aperture and the object based upon counts of emitted X-ray photons of gas within the non-vacuum environment that is situated between the object and the aperture.

72. An interface between a vacuum environment and a non-vacuum environment, the interface comprises at least one aperture sealed by at least one ultra thin membrane that is substantially transparent to electrons and withstands a pressure difference between the vacuum environment and the non-vacuum environment;

wherein a component that comprises the at least one aperture is flexibly coupled to another component of the interface.

73. The interface according to claim 72 wherein the aperture comprises an aperture array and wherein apertures of the aperture array are positioned at a single horizontal plain.

74. The interface according to claim 72 wherein the aperture comprises an aperture array and wherein at least one aperture of the aperture array is positioned at a different height than at least one other aperture of the aperture array.

75. The interface according to claim 72 wherein the aperture comprises an aperture array and wherein at least one aperture of the aperture array enables an acquisition of a higher resolution image than at least one other aperture of the aperture array.

76. A scanning electron microscope comprising:

an electron beam source positioned in a vacuum environment;

the electron beam source is adapted to generate at least one electron beam;

an interface between a vacuum environment and a non-vacuum environment, the interface comprises at least one aperture sealed by at least one ultra thin membrane that is substantially transparent to electrons and withstands a pressure difference between the vacuum environment and the non-vacuum environment;

wherein a component that comprises the at least one aperture is flexibly coupled to another component of the interface;

electron optics adapted to direct the at least one electron beam through at least one aperture and towards an object located in the non-vacuum environment; and

a detector that detects particles generated in response to an interaction between the at least one electron beam and the object.