GRID FOR RADIATION IMAGING AND METHOD FOR PRODUCING THE SAME

• US 20120307976A1
• Filed: 03/18/2011
• Published: 12/06/2012
• Est. Priority Date: 03/30/2010
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: Kaneko, Yasuhisa
• Granted Patent: US 8,989,353 B2
• Time in Patent Office: Days
• US Class Current: 378/62
• CPC Class Codes: A61B 6/4092 for producing synchrotron radiation
• CPC Class Codes: A61B 6/4291 the detector being combined with a grid or grating
• CPC Class Codes: A61B 6/484 involving phase contrast X-ray imaging
• CPC Class Codes: C25D 3/00 Electroplating: Baths therefor
• CPC Class Codes: G21K 1/02 using diaphragms, collimators
• CPC Class Codes: G21K 1/025 using multiple collimators, e.g. Bucky screens; other devices for eliminating undesired or dispersed radiation
• CPC Class Codes: G21K 1/06 using diffraction, refraction or reflection, e.g. monochromators G21K1/10, G21K7/00 take precedence
• CPC Class Codes: G21K 2201/06 using diffractive, refractive or reflecting elements
• CPC Class Codes: G21K 2201/067 Construction details
• CPC Class Codes: G21K 2207/005 Methods and devices obtaining contrast from non-absorbing interaction of the radiation with matter, e.g. phase contrast

Abstract

A conductive substrate (18) and an etching substrate (20) are bonded to each other. An etch mask (25) is formed on the etching substrate (20) using a photolithography technique. On the etching substrate (20), grooves (20a) and X-ray transmitting sections (14b) are formed by dry etching using Bosch process. The grooves (20a) are filled with Au (27) by an electroplating method using the conductive substrate (18) as an electrode. Thus, X-ray absorbing sections (14a) are formed.

Claims

1. A grid for radiation imaging comprising:

a plurality of radiation absorbing sections extending in an extending direction;

a plurality of radiation transmitting sections extending in the extending direction, the radiation absorbing sections and the radiation transmitting sections being alternately arranged in an arranging direction orthogonal to the extending direction; and

a plurality of transmitting-section bridging portions for coupling the radiation transmitting sections.

2. The grid of claim 1, wherein each of the transmitting-section bridging portions couples the two or more radiation transmitting sections in the arranging direction.

3. The grid of claim 1, wherein the transmitting-section bridging portions are arranged in a staggered arrangement.

4. The grid of claim 1, wherein the transmitting-section bridging portions are arranged in a slanting direction relative to the arranging direction.

5. The grid of claim 1, wherein the transmitting-section bridging portions adjacent in the arranging direction have a random interval in the extending direction.

6. The grid of claim 5, wherein an arrangement pitch of the transmitting-section bridging portions adjacent in the extending direction is random.

7. The grid of claim 5, wherein an arrangement pitch of the transmitting-section bridging portions adjacent in the extending direction takes a value distributed within a range relative to a central value.

8. The grid of claim 5, wherein an arrangement pitch of the transmitting-section bridging portions adjacent in the extending direction takes a prime number.

9. The grid of claim 1, wherein an arrangement pitch of the transmitting-section bridging portions in the extending direction is five or more times as wide as a width of the radiation absorbing section in the arranging direction.

10. The grid of claim 1, wherein the transmitting-section bridging portion is arranged between the radiation transmitting sections.

11. The grid of claim 10, wherein the transmitting-section bridging portion is provided integrally with the radiation transmitting section.

12. The grid of claim 1, wherein the transmitting-section bridging portion is formed through the radiation absorbing section and the radiation transmitting section in the arranging direction.

13. The grid of claim 10, wherein a width of the transmitting-section bridging portion in an X-ray transmission direction orthogonal to the extending direction and the arranging direction is smaller than a width of the radiation transmitting section.

14. The grid of claim 1, wherein the transmitting-section bridging portion couples the radiation transmitting sections across the radiation absorbing section.

15. The grid of claim 1, wherein the transmitting-section bridging portion is composed of a coupling portion and a reinforcing member for reinforcing the coupling portion, and the coupling portion couples end portions of the radiation transmitting sections in a radiation transmitting direction orthogonal to the extending direction and the arranging direction.

16. The grid of claim 1, further including a plurality of absorbing-section bridging portions for coupling the radiation absorbing sections.

32. The grid of claim 1, wherein the grid for radiation imaging is used as a first grid in a radiation imaging system composed of the first grid for passing radiation emitted from a radiation source to form a first periodic pattern, an intensity modulator for providing intensity modulation to the first periodic pattern in at least one of relative positions out of phase with the first periodic pattern, a radiation image detector for detecting a second periodic pattern generated in the relative position by the intensity modulator, and a processing section for imaging phase information based on at least one of the first and second periodic patterns detected by the radiation image detector.

33. The grid of claim 1, wherein the grid for radiation imaging is used as a second grid in a radiation imaging system composed of a first grid for passing radiation emitted from a radiation source to form a first periodic pattern, the second grid periodically arranged with a grid structure composed of a transmitting portion for transmitting the first periodic pattern and an absorbing portion for absorbing the periodic pattern to provide intensity modulation to the first periodic pattern in at least one of relative positions out of phase with the first periodic pattern, a scanning section for moving at least one of the first and second grids at a predetermined pitch in a periodic direction of the grid structure of the first and second grids and each position moved by the scanning position corresponding to the relative position, an image detector for detecting a second periodic pattern image generated in the relative position by the second grid, and a processing section for imaging phase information based on at least one of the first and second periodic patterns detected by the radiation image detector.

34. The grid of claim 1, wherein, the grid for radiation imaging is used as a third grid in a radiation imaging system composed of a first grid for passing radiation emitted from a radiation source to form a first periodic pattern, an intensity modulator for providing intensity modulation to the first periodic pattern in at least one of relative positions out of phase with the first periodic pattern, a radiation image detector for detecting a second periodic pattern generated in the relative position by the intensity modulator, a processing section for imaging phase information based on at least one of the first and second periodic patterns detected by the radiation image detector, and the third grid disposed between the radiation source and the first grid to area-selectively shield the radiation emitted from the radiation source to form a plurality of linear light sources.

17. A grid for radiation imaging comprising:

a radiation absorbing section for absorbing radiation; and

a radiation transmitting section made of a semiconductor of one conductivity type doped with an impurity.

18. The grid of claim 17, wherein a semiconductor substrate is bonded to one of faces of a grid layer composed of the radiation absorbing section and the radiation transmitting section, and the semiconductor substrate has a conductivity type opposite to the conductivity type of the radiation transmitting section by doping of another impurity.

19. The grid of claim 18, wherein the semiconductor substrate of the opposite conductivity type is composed of a conductive thin-layer made of the semiconductor of the opposite conductivity type and a support substrate.

20. The grid of claim 17, wherein the semiconductor of one conductivity type is made of an n-type semiconductor.

30. The grid of claim 17, wherein the radiation absorbing section and the radiation transmitting section extend in an extending direction, and a plurality of the radiation absorbing sections and a plurality of the radiation transmitting sections are alternately arranged in an arranging direction orthogonal to the extending direction.

31. The grid of claim 17, wherein one of the radiation absorbing sections and the radiation transmitting sections are arranged in cross-like shape, and the other of the radiation absorbing sections and the radiation transmitting sections are surrounded by the radiation absorbing sections or the radiation transmitting sections arranged in the cross-like shape.

21. A grid for radiation imaging comprising:

a semiconductor substrate of one conductivity type doped with an impurity; and

a radiation absorbing section provided on the semiconductor substrate.

22. The grid of claim 21, wherein the semiconductor substrate is made of a p-type semiconductor.

23. A grid for radiation imaging comprising:

a grid layer having a radiation absorbing section and a radiation transmitting section;

a support layer bonded to the grid layer; and

a plurality of depression portions provided on at least one of bonding surfaces of the grid layer and the support layer.

24. The grid of claim 23, wherein the size of each of the depression portions is equal to or smaller than a pixel size of a radiation image detector for detecting radiation passed through the grid for radiation imaging.

25. The grid of claim 23, wherein each of the depression portions is formed from a linear depression extending in the arranging direction.

26. A grid for radiation imaging comprising:

a radiation absorbing section for absorbing radiation;

a radiation transmitting section for passing the radiation; and

an anchor layer having a rough supporting surface for supporting the radiation absorbing section and the radiation transmitting section.

27. A grid for radiation imaging comprising:

a grid layer having a radiation absorbing section and a radiation transmitting section; and

a support layer for supporting the grid layer, the grid layer and the support layer being bonded to a curved surface provided on a radiation-transmissive holding member and bent.

28. The grid of claim 27, wherein the support layer is made of an inorganic material, and a total thickness of the grid layer and the support layer is less than 200 μ

m.

29. The grid of claim 27, wherein the support layer is made of an organic material.

35. A method for producing a grid for radiation imaging comprising the steps of:

bonding a radiation-transmissive first substrate and an electrically conductive and radiation-transmissive second substrate;

etching the first substrate through an etch mask to form grooves and a plurality of radiation transmitting sections disposed between the grooves; and

plating the grooves by filling of a radiation absorbing material to form a plurality of radiation absorbing sections by an electroplating method using the second substrate as an electrode.

36. The method of claim 35, wherein deep dry etching is used for the etching.

37. The method of claim 35, wherein the second substrate has substantially the same thermal expansion coefficient as the first substrate.

38. The method of claim 35, wherein the second substrate is composed of a conductive thin-layer used as the electrode and a support substrate provided with the conductive thin-layer.

39. The method of claim 35, wherein the second substrate is made of a semiconductor, a same material as the first substrate.

40. The method of claim 39, wherein the second substrate is composed of the semiconductor used as the electrode and a support substrate made of an insulator.

41. The method of claim 39, wherein the first substrate is made of a semiconductor of one conductivity type doped with an impurity, and the second substrate is made of a semiconductor of a conductivity type opposite to the one conductivity type, doped with another impurity.

42. The method of claim 41, wherein the semiconductor of one conductivity type is an n-type semiconductor.

43. The method of claim 35, wherein at least a surface of the first substrate has an insulation property after the etching step.

44. The method of claim 43, wherein the first substrate has a specific resistance equal to or larger than 100 Ω

·

cm.

45. The method of claim 44, further including a step for forming an insulating layer on a part or an entire of the surface of the first substrate after the etching step.

46. The method of claim 45, wherein the insulating layer is hydrophilic.

47. The method of claim 43, wherein the specific resistance is increased by ion implantation to the first substrate after the etching step.

48. The method of claim 35, wherein the first substrate is removed by a predetermined thickness from at least one of faces of the first substrate after the plating step.

49. The method of claim 48, wherein the second substrate is removed when the first substrate is removed by the predetermined thickness from the face to which the second substrate is bonded.

50. The method of claim 49, wherein the first substrate is removed by the predetermined thickness from the face to which the second substrate is bonded, after the first substrate is removed by the predetermined thickness from and a protective layer is formed on the face not bonded to the second substrate.

51. The method of claim 35, wherein etching is performed to the first substrate after the plating step to remove the radiation transmitting sections between the radiation absorbing sections.

52. The method of claim 35, further including a step of forming a plurality of depression portions on at least one of bonding surfaces of the first and second substrates before the bonding step.

53. The method of claim 35, further including the steps of:

making the bonding surface of the first substrate into a rough surface before the bonding step;

forming a radiation-transmissive and electrically conductive anchor layer on the rough surface; and

polishing the anchor layer to improve smoothness of the anchor layer.

54. The method of claim 35, wherein the radiation absorbing sections and the radiation transmitting sections extend in an extending direction and are alternately arranged in an arranging direction orthogonal to the extending direction, and a transmitting-section bridging portion for coupling the radiation transmitting sections in the arranging direction is formed before the plating method.

55. The method of claim 54, wherein the etch mask has a plurality of line patterns extending in the extending direction and arranged in the arranging direction and a plurality of bridge patterns for coupling the line patterns in the arranging direction, and the transmitting-section bridging portion is formed in the groove by etching the first substrate through the etch mask.

56. The method of claim 55, wherein the bridge pattern is made thinner than the mask pattern and the transmitting-section bridging portion is formed on a bottom portion of the groove using a difference in etching rates between the mask pattern and the bridge pattern.

57. The method of claim 54, wherein the etch mask is provided on the first substrate and has a plurality of line patterns extending in the extending direction and arranged in the arranging direction and the transmitting-section bridging portion is composed of bridge patterns provided on the etch mask so as to couple the line patterns in the arranging direction.

58. The method of claim 54 further including the steps of:

forming a plurality of bridge masks in the arranging direction on the first substrate, the bridge masks constituting the transmitting-section bridging portions;

etching the first substrate to a predetermined depth through the bridge masks;

forming the etch mask provided with a plurality of line patterns extending in the extending direction and arranged in the arranging direction and a plurality of bridge patterns for coupling the line patterns and covering the bridge masks on the first substrate after the etching; and

etching the first substrate through the etch mask to form the transmitting-section bridging portions, each of the transmitting-section bridging portions being composed of the bridge mask, the bridge pattern, and a coupling portion for coupling the radiation transmitting sections under the bridge mask.

59. The method of claim 54, further including the steps of:

forming a plurality of transmitting-section bridging portions extending in the arranging direction and arranged in the extending direction on the first substrate;

embedding the transmitting-section bridging portions inside the first substrate by forming a layer on a surface of the first substrate on which the transmitting-section bridging portions are formed or by bonding substrates to increase thickness of the first substrate; and

etching the first substrate through the etch mask to form the grooves and the radiation transmitting sections, the transmitting-section bridging portions being formed through the grooves.

60. The method of claim 57, wherein a width of the transmitting-section bridging portion in the extending direction has a dimension with which the first substrate under the transmitting-section bridging portion is removable by side etching during the etching of the first substrate.

61. The method of claim 54, further including a step of forming an absorbing-section bridging portion for coupling the radiation absorbing sections in the arranging direction.

62. The method of claim 38, further including the steps of:

emitting a first examination light passing through the support substrate and the conductive thin-layer and examining an etching state of the first substrate based on the first examination light passed through the grooves; and

emitting second examination light passing the support substrate, the conductive thin-layer, and the first substrate after the plating step and examining a filling state of the radiation absorbing material based on the second examination light passed through the first substrate.

63. The method of claim 62, wherein mathematical expressions (1) and (2) are satisfied where λ

e denotes an absorption wavelength of the first substrate, and λ

d denotes an absorption wavelength of the conductive thin-layer, and λ

s denotes an absorption wavelength of the support substrate, and λ

m1 denotes a wavelength of the first examination light, and λ

m2 denotes a wavelength of the second examination light.

λ

d,λ

s<

λ

m1<

λ

e 

 

(1)

λ

d,λ

s,λ

e<

λ

m2 

 

(2)

64. The method of claim 63, wherein the first examination light is visible light with the wavelength λ

m1 from 0.4 μ

m to 0.7 μ

m, and the second examination light is infrared light with the wavelength λ

m2 of equal to or longer than 0.7 μ

m.

65. The method of claim 64, wherein the conductive thin-layer is a transparent conductive layer of ITO, IZO, or ZnO, or a metal thin-layer of Au, Pb, Pt, Ni, Cr, or Ti with a thickness equal to or smaller than 500 Å

, or the transparent conductive thin-layer provided with the metal thin-layer on at least one of surfaces.

66. The method of claim 65, wherein the support substrate is made of glass.

67. The method of claim 35, further including a step of bending the grid by bonding the grid to a curved surface provided in radiation-transmissive holding member.

68. The method of claim 67, wherein the second substrate is made of an inorganic material and a total thickness of the first substrate and the second substrate is less than 200 μ

m.

69. The method of claim 67, wherein the second substrate is composed of an organic material and a conductive thin-layer provided on the organic material.

70. The method of claim 67, wherein the second substrate is composed of a conductive thin-layer and a support substrate provided with the conductive thin-layer, and the support substrate is composed of a reinforcing substrate having rigidity against bending during the etching step and the plating step and an organic material layer formed on the reinforcing substrate, and the reinforcing substrate is removed or thinned after the plating step.