JP2013058591A - Electron source block wafer dicing method, electron source block, and x-ray diagnostic device using its electron source block - Google Patents

Abstract

PROBLEM TO BE SOLVED: To diagnose an electron source block wafer with a narrow dicing street width at high accuracy without giving thermal damage on an electron emission element.SOLUTION: This method include the steps of: adhering a silicon substrate 33 on a lower face of a glass substrate 32; forming a group of electron emission elements 45 on an upper surface of the glass substrate 32 for every electron source block 35 and manufacturing an electron source block wafer 43; radiating laser light along a cutting schedule line of a street 34 between the electron source blocks 35 on the electron source block wafer 43 while a condensing point is focused to the inside of the silicon substrate 33 adhered to the lower face of the glass substrate 32 rather than the upper face of the glass substrate 32 to form a modified region 37 in the silicon substrate 33; and dividing the glass substrate 32 and the silicon substrate 33 along the cutting schedule line with the modified region 37 as a starting point.

Description

  The present invention relates to an electron source block wafer dicing method, an electron source block, and an X-ray diagnostic apparatus using the electron source block, for example.

  The basic configuration of an X-ray sensor includes a photoelectric conversion film that generates holes according to the intensity of received X-rays and an electron source that emits electrons to the holes generated in the photoelectric conversion film. .

  This electron source has a configuration including a substrate and a plurality of electron source block units tiled on the substrate at high density so as to correspond to pixels on the X-ray image.

  In this method of manufacturing the electron source block unit, it is necessary to divide the electron source block into a predetermined size from one wafer. At the time of this division, blade dicing is used to define the electron source block. A semiconductor wafer on which a plurality of electron source blocks are formed is diced (for example, Patent Document 1 below).

  As another dicing method, a laser having a wavelength that is transmitted to the substrate is adjusted by multiphoton absorption along the planned cutting line of the substrate with a converging point inside the substrate. The laser processing method provided with the process of forming a quality area | region was used (for example, the following patent document 2).

Japanese Patent Application Laid-Open No. 11-177771 JP 2002-192367 A

  The problem of the electron source block diced by the above-mentioned conventional manufacturing method is that the electron source block cannot be cut with high precision with a narrow dicing street width, and an electron source having uniform electron emission characteristics from a plurality of electron source block wafers. When a plurality of blocks are selected and used as an X-ray sensor by arranging a plurality of blocks, the pixel interval is widened at the joint and line defects are generated.

  In other words, the electron source block wafer was cut using blade dicing. However, in blade dicing, the blade thickness is 50 to 100 microns, and although the water is cooled, the amount of heat generated at the cutting portion is larger, and is 100 than that of the dicing line. If the elements are not separated by more than a micron, there is a problem that the elements are destroyed by heat, and narrow dicing cannot be realized. Further, chipping and burrs of 20 to 30 microns occurred on the cut end face, and it was impossible to process with high accuracy.

  Also, in laser dicing, when cutting a glass substrate, the conditions vary depending on the type of glass, so cutting is difficult, and the cutting accuracy is straight end face straightness ± 5 to 10 microns, cross section straightness ± 5 to 10 microns, It could not be processed with high accuracy. In the case of cutting a silicon substrate, although the cutting accuracy can achieve end face straightness ± 1 to 2 microns and cross section straightness ± 1 to 2 microns, the heat is generated when the modified region is formed. Therefore, it is necessary to separate them by 20 microns or more, and narrow dicing cannot be realized.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to cut an electron source block from an electron source block wafer with a narrow dicing street width with high accuracy without causing thermal damage to the element.

  In order to achieve this object, the electron source of the present invention is a method of dicing an electron source block from an electron source block wafer formed from a plurality of electron source blocks, and bonding a silicon substrate to the lower surface of a glass substrate A step of manufacturing an electron source block wafer in which an electron-emitting device group is formed for each electron source block on the upper surface of the glass substrate, and a street cutting planned line between the electron source blocks on the electron source block wafer. Along the step of irradiating a laser beam from the upper surface of the glass substrate to the inside of the silicon substrate bonded to the lower surface of the glass substrate with a focusing point to form a modified region in the silicon substrate; And cleaving the glass substrate and the silicon substrate from the modified region as a starting point along the line, It is intended to achieve the fiscal objectives of.

  As described above, the electron source block wafer dicing method according to the present invention is a method of dicing an electron source block from an electron source block wafer formed of a plurality of electron source blocks, and a silicon substrate on a lower surface of a glass substrate. A step of forming an electron-emitting device group for each electron source block on the upper surface of the glass substrate to manufacture an electron source block wafer, and a street cutting between the electron source blocks on the electron source block wafer A step of forming a modified region in the silicon substrate by irradiating a laser beam with a condensing point on the inside of the silicon substrate bonded to the lower surface of the glass substrate along a predetermined line, A step of cleaving the glass substrate and the silicon substrate from the modified region as a starting point along the planned cutting line. Because, without giving thermal damage to the electron-emitting device, it can be cut from the electron source block wafer with high precision electron source block at a narrow dicing street width.

  That is, along the planned cutting line of the street between the electron source blocks, by irradiating the laser beam with the focusing point inside the silicon substrate bonded in close contact with the glass substrate lower surface from the glass substrate upper surface, While suppressing thermal damage to the electron source element by the glass substrate, multiphoton absorption is caused at the condensing point of the silicon substrate, and a modified region serving as a starting point of cutting can be formed. Further, the glass substrate in the laser incident path also undergoes some photon absorption in the path, resulting in a glass structural change. In particular, since the condensing point is aligned inside the silicon substrate, this structural change becomes strong near the interface between the glass substrate and the silicon substrate, and if a force is applied from that portion, cracks will occur in the glass substrate in the laser incident direction. Becomes easier to extend. As a result, when the modified region in the silicon substrate is cleaved along the planned cutting line, the crack extends straight to the glass substrate and can be cleaved to the glass substrate. The dicing street width can be cut with high accuracy.

The block diagram of the X-ray diagnostic apparatus concerning embodiment of this invention The block diagram of the X-ray diagnostic apparatus concerning embodiment of this invention The perspective view which shows the external appearance of the X-ray sensor concerning embodiment of this invention Sectional drawing of the X-ray sensor concerning embodiment of this invention Sectional drawing of the principal part of the X-ray sensor concerning embodiment of this invention Control block diagram of X-ray sensor according to an embodiment of the present invention Process drawing concerning embodiment of this invention The top view of the process concerning embodiment of this invention The perspective view concerning embodiment of this invention The perspective view concerning embodiment of this invention The perspective view concerning embodiment of this invention The perspective view concerning embodiment of this invention Sectional drawing concerning embodiment of this invention

  Hereinafter, an embodiment of an X-ray sensor according to the present invention and an X-ray diagnostic apparatus using the X-ray sensor will be described with reference to the accompanying drawings. Note that the attached drawings are schematic views for easy understanding.

  First, the overall configuration of the X-ray diagnostic apparatus according to this embodiment will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a configuration diagram of an X-ray diagnostic apparatus according to an embodiment of the present invention. As shown in FIG. 1, the X-ray diagnostic apparatus includes an X-ray source 1 and an X-ray sensor 2 disposed to face the X-ray source 1 at a predetermined interval. By irradiating the imaging subject 3 with a line and causing the X-ray transmitted through the imaging subject 3 to enter the X-ray sensor 2, the internal state of the imaging subject 3 is visualized.

  Specifically, the X-ray source 1 is provided at one end of an arm 4 having a substantially semicircular shape when viewed from the side, and the X-ray sensor 2 is provided at the other end of the arm 4. In this way, the X-ray source 1 and the X-ray sensor 2 are arranged to face each other at a predetermined interval. Therefore, since the X-ray source 1 and the X-ray sensor 2 can be arranged to face each other with the arm 4 sandwiching the imaging target person 3 lying on the bed 5, the X-ray source 1 is irradiated and transmitted through the imaging target person 3. X-rays can be detected by the X-ray sensor 2.

  The arm 4 is rotatably attached to the apparatus main body 6. The apparatus body 6 incorporates a drive device (not shown) that rotates the arm 4. By doing in this way, it becomes possible to visualize the internal state of the person to be imaged 3 from various angles.

  FIG. 2 is a block diagram of the X-ray diagnostic apparatus according to the embodiment of the present invention.

  As shown in FIG. 2, the X-ray source 1 is connected to an X-ray control unit 7, and the X-ray control unit 7 is connected to a controller 8. The controller 8 controls the overall operation of the X-ray diagnostic apparatus. The X-ray control unit 7 controls an X-ray irradiation operation and an X-ray irradiation amount by the X-ray source 1 according to a command signal from the controller 8.

  The X-ray sensor 2 is connected to the image processing unit 9. The image processing unit 9 detects an electric signal (photoelectric conversion signal) extracted from the X-ray sensor 2 and performs image processing. The signal processed by the image processing unit 9 is transmitted to the controller 8. The controller 8 displays an image based on the amount (intensity) of X-rays detected by the X-ray sensor 2, that is, an image displaying an internal state of the imaging subject 3 on the monitor 10.

  The X-ray sensor 2 is also connected to the electron source control unit 11. The electron source control unit 11 is also connected to the controller 8. The electron source control unit 11 controls an electron beam irradiation operation and an electron beam irradiation amount by an electron source, which will be described later, in accordance with a command signal from the controller 8.

  A drive device (not shown) for rotating the arm 4 built in the apparatus main body 6 is connected to the movement control unit 13, and the movement control unit 13 is connected to the controller 8. The movement control unit 13 controls the rotation operation of the arm 4 according to a command signal from the controller 8.

  An input unit 14 is further connected to the controller 8. The controller 8 comprehensively controls the operation of the entire X-ray diagnostic apparatus according to a command input from the input unit 14.

  Next, the X-ray sensor 2 according to this embodiment will be described with reference to FIGS. FIG. 3 is a perspective view showing the appearance of the X-ray sensor according to the embodiment of the present invention, FIG. 4 is a sectional view of the X-ray sensor according to the embodiment of the present invention, and FIG. It is sectional drawing of the target part 12 which is a photoelectric converting film of the X-ray sensor 2 concerning the form of FIG. 6, FIG. 6 is a control block diagram of the X-ray sensor 2 concerning embodiment of this invention.

  Hereinafter, the photoelectric conversion film of the X-ray sensor 2 will be described as a target portion.

  As shown in FIGS. 3 and 4, the X-ray sensor 2 includes a mounting substrate 15 having a rectangular shape when viewed in plan. Also, as shown in FIG. 4, a rectangular electron source 16 is provided on the main surface of the mounting substrate 15, and a target portion 12 is disposed above the electron source 16.

  The target portion 12 includes an X-ray transmissive substrate 17 which becomes an X-ray incident surface, a thin film electrode 18 and a hole injection blocking layer 19 which are sequentially provided on the back side of the X-ray incident surface of the X-ray transmissive substrate. , A light conversion film layer 20 and an electron injection blocking layer 21.

  More specifically, the X-ray transparent substrate 17 is disposed to face the mounting substrate 15 so that the surface opposite to the surface on which X-rays are incident (X-ray incident surface) faces the electron source 16. Yes.

  The target unit 12 and the electron source 16 are configured to be vacuum-sealed in the main body case 2a so that the X-ray irradiation energy can be photoelectrically converted.

  As shown in FIG. 5, the target unit 12 includes a hole injection blocking layer 19 sequentially provided on the surface of the X-ray transparent substrate 17 on which the thin film electrode 18 is formed, and light having a charge multiplying function. It consists of a conductive light conversion film layer 20 and an electron injection blocking layer 21. Therefore, the X-ray transmissive substrate 17 is disposed to face the mounting substrate 15 so that the electron injection blocking layer 21 faces the electron source 16. Thereby, the electron source 16 can irradiate an electron beam toward the surface on the electron injection blocking layer 21 side.

  In addition, the light conversion film layer 20 in the present embodiment is configured by a sensitivity layer, but may be further configured by a relaxation layer, a hole trap layer, and a sensitivity layer in order from the X-ray incident surface.

  The hole trapping layer is a layer that traps holes generated by irradiation with X-rays or visible light. The relaxation layer and the hole trapping layer are provided with a scratch or a hole injection blocking layer. This is for the purpose of suppressing the occurrence of white flaws even when film thickness unevenness occurs.

  The charge multiplying function of the light conversion film layer 20 is based on the sensitivity layer, and the light conversion film layer 20 may be constituted only by the sensitivity layer.

Here, indium tin oxide (ITO), tin oxide or the like is used for the thin film electrode 18. The hole injection blocking layer 19 is made of cerium oxide (CeO ₂ ), the relaxation layer is made of amorphous selenium (a-Se), and the hole trapping layer is made of amorphous selenium (a-Se). Lithium fluoride (LiF) is used, amorphous selenium (a-Se) is used for the sensitivity layer, and antimony sulfide (Sb ₂ S ₃ ) is used for the electron injection blocking layer 21.

  As shown in FIG. 6, the electron source 16 is supplied with a voltage Vd for irradiating an electron beam. Further, the electron source 16 is connected to an X scan driver 27 and a Y scan driver 28 included in the electron source control unit 11. Therefore, the electron source 16 scans the surface of the target unit 12 on the electron injection blocking layer 21 side with an electron beam by the X scan driver 27 and the Y scan driver 28.

  In addition, the X-ray sensor 2 may include a mesh 29 provided with a plurality of openings, as shown in FIG. The mesh 29 is an intermediate electrode provided for accelerating, focusing, and collecting surplus electrons from the electron beam irradiated from the electron source 16, and is applied to the mesh voltage applying unit 30 included in the electron source control unit 11. Connected. The mesh voltage applying unit 30 applies a positive voltage (mesh voltage) Vmesh to the mesh 29. The mesh 29 can be formed of a known metal material, alloy, semiconductor material, or the like.

  The thin film electrode 18 is connected to a high voltage source 31 that supplies a high voltage Vharp. A high electric field is applied to the light conversion film layer 20 of the target unit 12 by the high voltage Vharp. Further, the thin film electrode 18 is connected to the image processing unit 9. As described above, the image processing unit 9 detects and processes the photoelectric conversion signal extracted from the thin film electrode 18. The level of the photoelectric conversion signal changes according to the amount of light (intensity) of light incident on the X-ray incident surface of the X-ray transmissive substrate 17.

  Now that the basic configuration and operation of the present embodiment have been understood, the characteristic points of the present embodiment will be described below.

  FIG. 7 is a process cross-sectional view of the electron source block wafer dicing method in this embodiment. First, in the first step (a), for example, a glass substrate 32 having a thickness of 0.5 mm and a silicon substrate 33 having a main surface of (100) having a thickness of 0.625 mm are bonded by anodic bonding. As a condition for anodic bonding, the glass substrate 32 and the silicon substrate 33 are overlapped and heated to about 400 to 500 ° C., and a negative voltage of about 500 V is applied to the glass substrate 32. At this time, the surface roughness Ra of the bonding surfaces of the glass substrate 32 and the silicon substrate 33 is preferably 0.5 nm or less. As a result, the glass substrate 32 and the silicon substrate 33 can be firmly bonded by a covalent bond without a gap. Ra is measured using NewView 5032 manufactured by Zygo, and the measurement area is 0.14 mm × 0.11 mm.

  Next, in the second step (b), for example, a plurality of electron source blocks 35 partitioned by 30 micron wide streets 34 are arranged so that the direction of the streets 34 is perpendicular to <0-11> of the silicon substrate 33. Alternatively, it is formed to be perpendicular to <0-1-1>. By doing so, the silicon substrate 33 can be cleaved at the cleavage plane in the cleaving step described later, and can be cut more accurately. Hereinafter, the entire substrate on which the plurality of electron source blocks 35 are formed is referred to as an electron source block wafer 43. FIG. 8A shows the electron source block wafer 43 as viewed from above. The electron-emitting device formed on the surface of the electron source block 35 may be a known Spindt-type electron source, a surface conduction electron-emitting device, or a carbon nanotube electron-emitting device.

  Subsequently, in the third step (c) shown in FIG. 7, along the planned cutting line 39 of the street, from the upper surface of the glass substrate 32 to the silicon substrate 33 side from the interface between the glass substrate 32 and the silicon substrate 33, for example, A focused region is adjusted to a depth of about 300 microns, and a pulsed laser 36 is irradiated to form a modified region 37. A view from above is shown in FIG. However, the glass substrate 32 and the silicon substrate 33 are illustrated as transparent so that the position where the modified region 37 is formed can be seen. The reason for using a pulsed laser is that when a solid laser is used in continuous oscillation, heat is trapped in the laser medium, and this heat expands the laser medium, acting as a lens and adversely affecting the laser optical path. This is because the cutting accuracy is deteriorated (called the lens effect).

The specifications of the laser used were as follows.
<Laser specification>
Light source: Semiconductor laser excitation Nd: YAG laser Wavelength: 1064 nm
Laser light spot cross-sectional area: 3.14 × 10 ⁻⁸ / cm ²
Oscillation form: Q switch pulse Repetition frequency: 100 kHz
Pulse width: 30ns
Output: 20μJ / pulse Laser light quality: TEM00
Deflection characteristics: straight line change The modified region 37 shown in FIG. 7C was formed under the laser light irradiation conditions as described above, but the peak power density at the focal point was 1 × 10 ⁸ (W / cm ² ) or more. Since multiphoton absorption occurs under certain conditions, this condition should be satisfied in order to form the modified region 37. The peak power density is determined by (energy per pulse of laser light at the condensing point) / (cross-sectional area of laser beam beam spot × pulse width). For this reason, the laser irradiation conditions are not limited to the above-described conditions, and may be selected under the conditions that the peak power density at the condensing point satisfies 1 × 10 ⁸ (W / cm ² ) or more.

  Subsequently, in the fourth step (d), by applying an external force to the silicon substrate 33 on which the modified region 37 is formed in the third step, along the planned cutting line 39 of the street, Cracks 38 are introduced starting from the modified region 37 inside the substrate 33, and the cracks 38 are also extended to the glass substrate 32 to cut the glass substrate 32 and the silicon substrate 33 with high accuracy.

  As a specific method of applying an external force, as shown in FIG. 9, on the expandable expand tape 41 stretched on the ring-shaped frame 40, the side opposite to the bonding surface of the silicon substrate 33 is used. Paste the surface. As a result, the electron source block wafer 43 on which the modified region 37 is formed is held by the expanded tape 41. Then, the expanding tape 41 stretched on the frame 40 and holding the wafer 43 is conveyed to the expanding device.

  Next, as shown in FIG. 10, the frame 40 on which the expanded tape 41 holding the electron source block wafer 43 in which the modified region 37 is formed is fixed on the cylindrical fixing member 42 of the expanding apparatus. . A cylindrical pressing member 44 for pushing up the expanding tape 41 to expand it is arranged inside the fixing member 42. Subsequently, as shown in FIG. 11, the expanding member 41 is expanded by raising the pressing member 44 of the expanding device, and a crack is generated starting from the modified region 37 formed in the silicon substrate 33. The electron source blocks 35 obtained by cutting along the line 39 are separated from each other. At this time, since the cut surfaces of the electron source blocks 35 are separated from each other, generation of particles due to friction between the cut surfaces can be prevented.

  As shown in the perspective view of FIG. 12, the electron source block 35 thus obtained is bonded to the interface between the modified region 37, the glass substrate 32, and the silicon substrate 33 on the fractured surface of the silicon substrate 33. The electron-emitting device 45 can be observed on the formed interdiffusion layer 46 and the surface side of the glass substrate 32.

  Although the mechanism by which the crack generated from the modified region formed in the silicon substrate 33 by the above method extends straight to the glass substrate 32 has not been fully clarified yet, the following is generally as follows. It has become.

  As shown in FIG. 7C, the laser beam is irradiated from the upper surface of the glass substrate 32 to the inside of the silicon substrate 33 that is bonded in close contact with the lower surface of the glass substrate 32, and is irradiated by the glass substrate 32. While suppressing thermal damage to the electron-emitting device (electron source), multiphoton absorption is caused at the condensing point of the silicon substrate 33 to form a modified region serving as a starting point for cutting.

  However, at the same time, in the laser incident path, it gradually weakens with increasing distance from the condensing point, but some photon absorption occurs, and structural changes (crystals) occur inside the glass along the laser incident direction. I think that it is easy to break preferentially when external stress is applied to that part.

  Therefore, as shown in FIG. 7D, a glass substrate in which a crack 38 generated from a modified region 37 formed inside the silicon substrate 33 is formed along the laser incident path on the extension line of the crack 38. It extends straight to the structural change portion in 32 and can be cut with high accuracy.

  In the present embodiment, the thickness of the glass substrate 32 is 0.5 mm and the thickness of the silicon substrate 33 is 0.625 mm. However, the glass substrate 32 may be thinner than the silicon substrate 33. In this way, when the crack 38 generated from the modified region 37 formed in the silicon substrate 33 in the fourth step is extended into the glass substrate 32, it can be extended straight.

  Further, the silicon substrate 33 having a main surface of (100) is used, but it may be (110). However, in this case, it is necessary to form the street so that the direction of the street is perpendicular to <001> or perpendicular to <1-10>.

  Further, when the thickness of the silicon substrate 33 is increased and it becomes difficult to cleave by forming only the modified region single layer, a plurality of modified regions 37 may be formed as shown in FIG. Otherwise, when an external force is applied from the modified region 37 to generate the crack 38, there is a high possibility that the crack 38 does not extend straight along the planned cutting line in the silicon substrate 37. Because.

  In addition, the expanded tape is pasted and cleaved after the end of the third step, but before the second step is performed, the expanded tape is pasted, irradiated with laser light, and set in the expander for cleaving. It doesn't matter.

  Although the street width is 30 microns, the modified region 37 can be formed without thermally damaging the electron-emitting device 45 up to 15 microns.

  As described above, the electron source dicing method of the present invention is a method of dicing an electron source block from an electron source block wafer formed from a plurality of electron source blocks, and bonding a silicon substrate to the lower surface of a glass substrate. Forming a group of electron-emitting devices for each electron source block on the upper surface of the glass substrate, manufacturing an electron source block wafer, and a planned cutting line of a street between the electron source blocks on the electron source block wafer; Along the step of irradiating a laser beam from the upper surface of the glass substrate to the inside of the silicon substrate bonded to the lower surface of the glass substrate with a focusing point to form a modified region in the silicon substrate; And a step of cleaving the glass substrate and the silicon substrate from the modified region as a starting point along the line. The Kkuweha, without giving thermal damage to the electron-emitting device, can be cut with high accuracy in a narrow dicing street width.

  That is, along the planned cutting line of the street between the electron source blocks, by irradiating the laser beam with the focusing point inside the silicon substrate bonded in close contact with the glass substrate lower surface from the glass substrate upper surface, While suppressing thermal damage to the electron source element by the glass substrate, multiphoton absorption is caused at the condensing point of the silicon substrate, and a modified region serving as a starting point of cutting can be formed. Further, the glass substrate in the laser incident path also undergoes some photon absorption in the path, resulting in a glass structural change.

  In particular, since the condensing point is aligned inside the silicon substrate, this structural change becomes strong near the interface between the glass substrate and the silicon substrate, and if a force is applied from that portion, cracks in the glass substrate in the laser incident direction. Becomes easier to extend. As a result, when the modified region in the silicon substrate is cleaved along the planned cutting line, the crack extends straight to the glass substrate and can be cleaved to the glass substrate. The dicing street width can be cut with high accuracy.

  Therefore, application to a high-definition large-area X-ray sensor free of line defects and an X-ray diagnostic apparatus using the same is greatly expected.

DESCRIPTION OF SYMBOLS 1 X-ray source 2 X-ray sensor 3 Image pick-up person 4 Arm 5 Bed 6 Apparatus main body 7 X-ray control part 8 Controller 9 Image processing part 10 Monitor 11 Electron source control part 12 Target part 13 Movement control part 14 Input part 15 Mounting board 16 Electron Source 17 X-Ray Transparent Substrate 18 Thin Film Electrode 19 Hole Injection Blocking Layer 20 Photoconversion Film Layer 21 Electron Injection Blocking Layer 27 X Scan Driver 28 Y Scan Driver 29 Mesh 30 Mesh Voltage Applying Section 31 High Voltage Source 32 Glass Substrate 33 Silicon substrate 34 Street 35 Electron source block 36 Laser 37 Modified region 38 Crack 39 Line to be cut 40 Frame 41 Expanding tape 42 Fixed member 43 Electron source block wafer 44 Press member 45 Electron emitting element 46 Interdiffusion layer

Claims (9)

A method of dicing an electron source block from an electron source block wafer formed from a plurality of electron source blocks,
Bonding a silicon substrate to the lower surface of the glass substrate;
Forming an electron-emitting device group for each electron source block on the upper surface of the glass substrate, and manufacturing an electron source block wafer;
Along the planned cutting line of the street between the electron source blocks on the electron source block wafer, a laser beam is irradiated from the upper surface of the glass substrate to the inside of the silicon substrate bonded to the lower surface of the glass substrate with a focusing point being irradiated. Forming a modified region in the silicon substrate;
A dicing method for an electron source block wafer, comprising: a step of cleaving a glass substrate and a silicon substrate starting from the modified region along the scheduled cutting line. 2. The electron source block wafer dicing method according to claim 1, wherein the step of bonding the silicon substrate to the lower surface of the glass substrate uses anodic bonding. 3. The electron source block wafer dicing method according to claim 2, wherein a surface roughness Ra of the bonding surface of the glass substrate and the bonding surface of the silicon substrate is 0.5 nm or less. 4. The electron source block wafer dicing method according to claim 1, wherein the silicon substrate is thicker than the glass substrate. 5. The main surface of the silicon substrate is (100), and the planned cutting line is formed in a direction perpendicular to <110> or in a direction perpendicular to <−110>. The electron source block wafer dicing method according to claim 1. The main surface of the silicon substrate is (110), and the planned cutting line is formed in a direction perpendicular to <001> or in a direction perpendicular to <0-1-1>. 6. The method of dicing an electron source block wafer according to any one of 5 above. The step of cleaving the glass substrate and the silicon substrate is performed by attaching an expandable expandable tape to the surface on the silicon substrate side, and extending the glass substrate above the planned cutting line of the silicon substrate and silicon substrate by expanding the expandable tape. 7. The method of dicing an electron source block wafer according to claim 1, wherein the cutting is performed with the modified region of the substrate as a starting point. An electron source block obtained by the electron source block wafer dicing method according to claim 1, comprising a glass substrate, an electron-emitting device formed on the glass substrate, and a lower surface of the glass substrate. An electron source comprising a silicon substrate bonded to the side, wherein a modified region is formed at a cut surface of the silicon substrate, and an interdiffusion layer is formed at a cut surface at the interface between the glass substrate and the silicon substrate. block. An X-ray source and an X-ray sensor disposed opposite to the X-ray source at a predetermined interval;
The X-ray sensor is an X-ray diagnostic apparatus in which a target unit and an electron source are sequentially provided from an X-ray incident side, and the electron source uses at least one electron source block according to claim 8.

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