JP2014225401A - Target for x-ray generation and x-ray generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a target for X-ray generation capable of specifying a target part quickly and accurately.SOLUTION: A target T includes a substrate 21 composed of an insulating material, and having a first principal surface 21a and a second principal surface 21b facing each other, where a bottomed hole H is formed from the first principal surface 21a side, a target part 23 composed of a metal material and buried in the hole H, and a mark part 27 composed of a metal material, and located on the first principal surface 21a side, while separated from the target part 23 when viewing from the facing direction A of the first and second principal surfaces 21a, 21b. When viewing from the facing direction A, the surface area of the mark part 27 is larger than that of the target part 23, and the length of the mark part 27 is smaller than that of the target part 23, when viewing from the facing direction A.

Description

  The present invention relates to an X-ray generation target used in an X-ray generation apparatus and an X-ray generation apparatus including the same.

  As an X-ray generation target, a target including a substrate and a target portion embedded in the substrate is known (for example, see Patent Document 1). In the X-ray generation target described in Patent Document 1, a single columnar metal wire made of tungsten or molybdenum is embedded in a substrate made of a light element such as beryllium or carbon.

JP 2004-028845 A

  In order to meet the demand for further miniaturization of the X-ray focal diameter, it is necessary to further reduce the size of the target portion. On the other hand, when the target portion has a smaller size (for example, nanometer size), it is necessary to specify the position of the target portion in the target in order to ensure that the focused electron beam is incident on the target portion. . For this reason, for example, it is conceivable to scan the electron beam on the target and specify the position of the target portion using the information. However, since the target portion is minute, the signal amount (signal change amount) obtained by scanning is also minute, and it was necessary to reliably detect a minute signal (signal change) in order to obtain necessary information. For this purpose, it is necessary to reduce the scanning speed. Thus, it is not easy to specify the position of the target, and it takes time to specify the target.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an X-ray generation target and an X-ray generation apparatus that can quickly and accurately specify a target portion.

  The target for X-ray generation according to the present invention is made of an insulating material, has a first main surface and a second main surface facing each other, and is formed with a hole extending in the opposing direction of the first and second main surfaces. An X-ray generation target comprising a substrate and a target portion made of a metal material and embedded in a hole, the target portion made of a metal material, located on the first main surface side and viewed from the opposite direction The mark portion is arranged so as not to overlap with the mark portion, and the surface area of the mark portion is larger than the surface area of the target portion when viewed from the facing direction, and the length dimension of the mark portion in the facing direction is the length of the target portion. It is characterized by being smaller than the height dimension.

  In this X-ray generation target, the mark portion is disposed on the first main surface side of the substrate, and the surface area of the mark portion is larger than the surface area of the target portion. Thereby, the position information of the mark part can be generated reliably. Further, the mark portion is separated so as not to overlap the target portion when viewed from the facing direction of the first and second main surfaces, and the length dimension (thickness) of the mark portion in the facing direction is the length of the target portion. Since it is smaller than the dimension (thickness), the mark portion and the target portion have a difference in the characteristics indicated by the incident electron beam. Therefore, the mark portion and the target portion can be reliably identified. Thereby, in the target for X-ray generation, since the position of a target part can be specified on the basis of the mark part which is easy to detect and distinguishable from a target part, a target part can be specified quickly and accurately.

  In one embodiment, the mark part may be arranged around the target part. Thereby, in the target for X-ray generation, a target part can be specified more quickly and accurately.

  In one embodiment, the mark portion may surround the target portion. Thereby, in the target for X-ray generation, a target part can be specified more quickly and accurately.

  In one embodiment, a plurality may be arranged around the target portion. Thereby, in the target for X-ray generation, a target part can be specified more quickly and accurately.

  An X-ray generation apparatus according to the present invention includes the above-described X-ray generation target, an electron gun that generates an electron beam incident on a target portion of the X-ray generation target, a focusing unit that focuses the electron beam, and an electron beam And a control unit for controlling the converging unit and the scanning unit, and the mark unit is located within the scanning region of the electron beam by the scanning unit and the target by the converging unit. It is arranged outside the focusing area of the electron beam focused on the part.

  In this X-ray generation apparatus, the mark portion of the target for X-ray generation is arranged in the scanning region of the electron beam by the scanning unit and outside the focusing region of the electron beam focused on the target unit by the focusing unit. . Thereby, in the X-ray generator, the electron beam is surely applied to the mark part during scanning, and the electron beam is not irradiated to the mark part when the electron beam focused on the target part is irradiated. Therefore, in the X-ray generator, it is possible to suppress the mark portion from affecting the X-ray generated from the target portion.

  According to the present invention, the target portion can be specified quickly and accurately.

It is a schematic block diagram which shows the X-ray generator which concerns on 1st Embodiment. It is the figure which looked at the target from the 1st principal surface side of a substrate. It is a figure which shows the cross-sectional structure in the III-III line in FIG. It is a figure which shows the cross-sectional structure of the target which concerns on another form. It is the figure which looked at the target which concerns on another form from the 1st main surface side of the board | substrate. It is the figure which looked at the target concerning a 2nd embodiment from the 1st principal surface side. It is a figure which shows the cross-sectional structure in the VII-VII line in FIG. It is a figure which shows the cross-sectional structure of the target which concerns on another form. It is the figure which looked at the target which concerns on another form from the main surface side of the board | substrate. It is the figure which looked at the target which concerns on another form from the main surface side of the board | substrate. It is the figure which looked at the target which concerns on 3rd Embodiment from the main surface side of the board | substrate. It is a figure which shows the cross-sectional structure in the XII-XII line | wire in FIG. It is a figure which shows the cross-sectional structure of the target which concerns on another form. It is the figure which looked at the target which concerns on another form from the 1st main surface side of the board | substrate. It is the figure which looked at the target concerning a 4th embodiment from the 1st principal surface side of a substrate. It is a figure which shows the cross-sectional structure in the XVI-XVI line | wire in FIG. It is a figure which shows the cross-sectional structure of the target which concerns on another form. It is the figure which looked at the target which concerns on another form from the 1st main surface side of the board | substrate.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted.

[First Embodiment]
With reference to FIG. 1, the structure of the X-ray generator which concerns on this embodiment is demonstrated. FIG. 1 is a schematic configuration diagram showing an X-ray generator according to the first embodiment.

  The X-ray generation apparatus 1 is an open type, and unlike a disposable sealed type, can create a vacuum state arbitrarily, such as a target (X-ray generation target) T, a cathode of an electron gun unit 3, etc. Exchange is possible. The X-ray generator 1 is in a vacuum state during operation, and has a cylindrical tubular portion 5 made of a conductive material, for example, stainless steel. The cylindrical portion 5 includes a lower electron gun housing portion 5a and an upper target holding portion 5b. The target holding portion 5b is attached to the electron gun housing portion 5a via a hinge (not shown). ing. Therefore, the upper part of the electron gun accommodating part 5a can be opened by rotating the target holding part 5b so as to lie down through the hinge, and the electron gun accommodated in the electron gun accommodating part 5a. Allows access to part 3 (cathode).

  In the target holding part 5b, a cylindrical coil part (focusing part) 7 that functions as a focusing lens and a cylindrical coil part (scanning part) 9 that functions as a deflection coil are provided. The electron passage 11 extends in the longitudinal direction of the cylindrical portion 5 so as to pass through the center of the cylindrical portion 5. The electron passage 11 is surrounded by the coil portions 7 and 9. A disk plate 13 is fixed to the lower end of the target holding portion 5 b so as to cover it, and an electron introduction hole 13 a that matches the lower end side of the electron passage 11 is formed at the center of the disk plate 13.

  An upper end of the target holding portion 5b is formed in a truncated cone, and a transmission type target T that is located on the upper end side of the electron passage 11 and forms an X-ray emission window is mounted on the top portion. Since the target T is detachably fixed by a detachable structure (not shown) so that the upper end of the electron passage 11 is vacuum-sealed in a grounded state, the target T, which is a consumable item, can be replaced.

  A vacuum pump 17 is fixed to the electron gun housing part 5a, and the vacuum pump 17 is for making the inside of the cylindrical part 5 into a high vacuum state. That is, when the X-ray generator 1 is equipped with the vacuum pump 17, the target T, the cathode, and the like can be exchanged.

  A mold power supply unit 19 that is integrated with the electron gun unit 3 is fixed to the base end side of the cylindrical unit 5. The mold power supply unit 19 is molded with an electrically insulating resin (for example, epoxy resin) and is housed in a metal case.

  In the mold power supply unit 19, a high voltage generation unit (not shown) that constitutes a transformer that generates a high voltage (for example, −tens of kV or less) is enclosed. The mold power supply unit 19 includes a block-shaped power supply main body 19a that is positioned on the lower side and has a rectangular parallelepiped shape, and a columnar neck 19b that protrudes upward from the power supply main body 19a into the electron gun housing 5a. Consists of. The high voltage generator is sealed in the power supply main body 19a with an electrically insulating resin. An electron gun portion 3 arranged so as to face the target T so as to sandwich the electron passage 11 is attached to the tip portion of the neck portion 19b. An electron emission control unit (not shown) electrically connected to the high voltage generation unit is enclosed in the power supply main body 19a of the mold power supply unit 19. The electron emission control unit is connected to the electron gun unit 3 and controls the timing of electron emission, tube current, and the like.

  Subsequently, the target T will be described. FIG. 2 is a view of the target as viewed from the first main surface side of the substrate. 3 is a diagram showing a cross-sectional configuration taken along line III-III in FIG. In the following targets T1, T2, and T3, for ease of illustration, the size, the separation distance, and the like of each component in the drawing do not necessarily match the actual numerical conditions. That is, in each drawing, the dimensional ratio of each component may be different from the actual one, and does not necessarily match the actual configuration.

  As shown in FIGS. 2 and 3, the target T includes a substrate 21, a target portion 23, a conductive layer 25, and a mark portion 27, and a transmission type target that also serves as an X-ray emission window; It has become. The substrate 21 is made of an electrically insulating material, for example, diamond, which generates little X-rays due to the incidence of electrons and is excellent in X-ray transmission and heat dissipation, and is a first and second main surface 21a which is a flat portion facing each other. , 21b. The first main surface 21a is a surface on the electron incident side, the second main surface 21b is a surface on the X-ray emission side, and the substrate 21 in the direction along the facing direction A of the first and second main surfaces 21a, 21b. The thickness is set to about 300 μm, for example.

  The target unit 23 is located on the first main surface 21 a side of the substrate 21. The target portion 23 is embedded in a hole extending in the facing direction A in the substrate 21, specifically, a hole H formed in a bottomed shape from the first main surface 21 a side. The target portion 23 is formed in a cylindrical shape from a metal (for example, tungsten, gold, platinum, or the like) made of a material different from that of the substrate 21 and is, for example, an end surface on the first main surface 21a side as viewed from the facing direction A. The outer diameter (diameter) D1 of the electron incident surface is about 100 nm to 2 μm, and the length (thickness) L1 in the direction along the facing direction A is about 500 nm to 4 μm. In the present embodiment, tungsten is employed as the metal of the target portion 23, the outer diameter D1 of the target portion 23 is, for example, 500 nm, and the length L1 is, for example, 1 μm.

  The conductive layer 25 is formed on the first main surface 21a side of the substrate 21 and suppresses charging of the first main surface 21a by the electron beam EB and protects the first main surface 21a against the electron beam EB. . The conductive layer 25 is made of, for example, a conductive material containing a transition element (more preferably, a first transition element), and is a conductive thin film made of, for example, titanium, chromium, or a conductive compound thereof. And The length (thickness) of the conductive layer 25 in the direction along the facing direction A is, for example, about 50 nm and is smaller than the length L1 of the target portion 23. For example, the conductive layer 25 is formed on the first main surface 21a by vapor deposition such as physical vapor deposition (PVD). Further, diamond doped with an impurity (for example, boron) may be used as the conductive layer 25. In this case, a diamond layer is formed by generating and growing diamond particles by a microwave plasma CVD method. The diamond layer is formed by doping boron. In the present embodiment, the conductive layer 25 is formed so as to expose the electron incident surface of the target unit 23, but may be formed so as to cover it.

  The mark portion 27 is located on the first main surface 21 a side of the substrate 21 and is disposed on the conductive layer 25. The mark part 27 is a part that generates position information as a reference when specifying the position of the target part 23. The mark portion 27 is disposed so as not to overlap the target portion 23 when viewed from the facing direction A of the first and second main surfaces 21 and 21b of the substrate 21. A plurality (four in this case) of the mark portions 27 are arranged on the circumference of the virtual circle S having the center of the target portion 23 as the center.

  The mark part 27 is arrange | positioned in the position which opposes on both sides of the target part 23, respectively. The mark portions 27 adjacent on the virtual circumference are equally spaced. Opposing directions of the pair of mark portions 27 are substantially orthogonal to each other. The distance d between the mark portion 27 and the target portion 23 (the shortest distance between the outer edges facing each other in the mark portion 27 and the target portion 23) is, for example, about 10 to 50 μm. When the outer diameter D1 of the target portion 23 is sufficiently smaller than the separation distance d, the radius of the virtual circle S can be approximated as the separation distance d. The mark portion 27 is formed in a disk shape from a metal (for example, tungsten, gold, platinum, etc.) made of a material different from that of the substrate 21. In the present embodiment, tungsten is adopted as the metal of the mark portion 27 as in the case of the target portion 23.

  The mark portion 27 is, for example, a flat columnar shape having an outer diameter (diameter) D2 of about 3 to 10 μm viewed from the facing direction A and a length (thickness) L in the direction along the facing direction A of about 50 to 500 nm. is there. In the present embodiment, the outer diameter D2 of the mark portion 27 is, for example, 5 μm, and the length L2 is, for example, 200 nm. The outer diameter D2 of the mark portion 27 is larger than the outer diameter D1 of the target portion 23 (D2> D1). That is, the surface area of the mark portion 27 (the area viewed from the electron incident direction) is larger than the surface area of the target portion 23. The length L2 of the mark portion 27 is shorter than the length L1 of the target portion 23 (L2 <L1), and is longer than the length of the conductive layer 25 in the direction along the facing direction A.

  Reference is again made to FIG. The X-ray generator 1 includes a backscattered electron detector 31 as a backscattered electron detector, a controller 33 as a controller, and an XY stage 34 as a mechanical moving mechanism of the target 23. The backscattered electron detector 31 holds the target so as to face the target portion 23 through a path (not shown) or at a position in the electron path 11 that is not affected by the electron beam EB toward the target T. It is arrange | positioned at the upper end side of the part 5b, and detects the electrons (reflected electrons) reflected by the target T. Moreover, you may provide the current detector 32 as an absorption electron detection part. The current detector 32 is electrically connected to the target T, detects an absorption current indicating the amount of the electron beam EB absorbed by the target T, and outputs the information to the controller 33 which is a control unit. Note that the controller 33 may include a current detection unit without separately providing a current detection unit. Further, both the reflected electron detection unit and the absorption electron detection unit may be provided, or only one of them may be provided. Moreover, as a control part, the control regarding the X-ray generator 1 may be performed by the single controller 33, or it may be provided with the some controller 33, and the control regarding the X-ray generator 1 may be performed by those cooperation. Good.

  The controller 33 performs various controls relating to the X-ray generation apparatus 1 and controls, for example, the high voltage generation unit and the electron emission control unit of the mold power supply unit 19. As a result, a predetermined current / voltage is applied between the electron gun unit 3 and the target T (target unit 23), and the electron beam EB is emitted from the electron gun unit 3. The electron beam EB emitted from the electron gun unit 3 is appropriately focused by the coil unit 7 controlled by the controller 33, enters the target T, and forms a focused region on the target T. This focusing region is an irradiation field E on the target T of the electron beam EB, and is substantially equal to a region where an electron incident trace is generated when the electron beam EB is incident on the target T. As shown in FIG. 2, the irradiation field E includes the target portion 23 in the range as viewed from the direction (electron incident direction) perpendicular to the target T along the facing direction A, and the outer edge thereof is It is included in the separation region between the target portion 23 and the mark portion 27. Since the outer edge of the separation region is equal to the virtual circle S concentric with the center of the target portion 23 described above, the outer diameter (diameter) ED of the irradiation field E is larger than the outer diameter D1 of the target portion 23 and It is smaller than the outer diameter (diameter) SD (D1 <ED <SD). The outer diameter ED of the irradiation field E is, for example, about 10 to 30 μm.

  As described above, since the mark portion 27 is disposed outside the region of the irradiation field E that is the focusing region, the X-ray XR having a desired focal diameter is extracted in a state where the noise component by the mark portion 27 is suppressed. be able to. In other words, when the target unit 23 is irradiated with the electron beam EB and X-rays are extracted, the controller 33 ensures that the coil unit 7 includes the target unit 23 but does not include the mark unit 27. By controlling to be E, the X-ray XR having a desired focal diameter can be extracted in a state where the noise component by the mark portion 27 is suppressed.

  Further, the controller 33 monitors the intensity of the reflected electrons detected by the reflected electron detector 31 (absorbed electrons detected by the current detector 32) in real time, and the intensity of the reflected electrons (absorbed electrons) from the target T and the target T. The coil unit 9 is controlled based on the position information set in. At this time, the coil unit 9 deflects the electron beam EB from the electron gun unit 3 so that the irradiation field E of the electron beam EB scans two-dimensionally on the target T. The scanning region (range) on the target of the electron beam EB scanned by the coil unit 9 is, for example, about 100 to 150 μm, and the target unit 23 and the mark unit 27 are arranged in one or more sets, preferably a plurality of sets in the scanning region. Is done. Further, when it is desired to further move the incident region of the electron beam EB on the target, the target unit 23 itself may be moved relative to the target holding unit 5b by the XY stage 34 based on the control of the controller 33. . Thus, by combining the deflection of the electron beam EB by the coil unit 9 and the movement of the target unit 23 itself by the XY stage 34, the target unit 23 can be used in a wider range.

  When the material is irradiated with the electron beam EB, an amount of reflected electrons depending on the atomic number of the material is emitted (the larger the atomic number, the more reflected electrons are emitted). In this embodiment, since the target portion 23 made of tungsten and the mark portion 27 made of tungsten are arranged on the substrate 21 made of diamond, the target portion 23 or the mark portion is located where more reflected electrons are detected. 27 can be determined. Therefore, the controller 33 controls the deflection of the electron beam EB so that more reflected electrons can be obtained.

  On the other hand, when the material is irradiated with the electron beam EB, the amount of electrons depending on the atomic number of the material is also absorbed. That is, the larger the atomic number, the smaller the absorbed current value, and the smaller the atomic number, the larger the absorbed current value. In this embodiment, since the target portion 23 made of tungsten and the mark portion 27 made of tungsten are provided on the substrate 21 made of diamond, the place where the absorption current value is small is determined as the target portion 23 or the mark portion 27. be able to. Therefore, the controller 33 controls the deflection of the electron beam EB so that the absorption current value becomes smaller. In the present embodiment, the absorbed current is equal to the target current.

  A method for specifying the target unit 23 will be described in more detail. The controller 33 controls the coil unit 9 to scan the electron beam EB on the target T, and monitors the intensity of the reflected electrons detected by the reflected electron detector 31 (absorbed electrons detected by the current detector 32). In the target T, since the mark portion 27 has a larger surface area than the target portion 23, compared with the target portion 23, the intensity (intensity change) of reflected electrons (absorbed electrons) when entering the irradiation field E of the electron beam EB. ) Is large. Therefore, the position information of the mark portion 27 on the target T can be reliably acquired as compared with the target portion 23.

  When the controller 33 acquires the position information of the mark portion 27, the controller 33 obtains the center of the virtual circle assuming that the position where the mark portion 27 is disposed is on the virtual circle circumference centered on the target portion 23. When the controller 33 obtains the center of the virtual circle, based on the position information of the center, the position information of the target unit 23 set in the target T, and the intensity of the reflected electrons (absorbed electrons), Identify the location. The controller 33 controls the coil unit 9 so that the irradiation field of the electron beam EB is positioned on the target unit 23. Alternatively, the position of the target unit 23 may be specified by predicting the position of the target unit 23 from the position information of the mark unit 27, and performing a precise rescan at a low speed starting from the mark unit 27. As described above, in the X-ray generator 1, the position of the target portion 23 is specified in the target T, and the target portion 23 is irradiated with the electron beam EB to generate X-rays having a desired focal diameter.

  In the present embodiment, the target portion 23 and the mark portion 27 are both made of tungsten. However, the length (thickness) of the mark portion 27 in the facing direction A is greater than the length (thickness) of the target portion 23 in the facing direction A. Also short. Therefore, the intensity of the reflected electrons (absorbed electrons) at the mark portion 27 is smaller than the intensity of the reflected electrons (absorbed electrons) at the target portion 23. Thereby, even if it forms the target part 23 and the mark part 27 with the same material, both can be distinguished.

  As described above, in the present embodiment, a plurality of mark portions 27 are arranged on the circumference of the virtual circle S around the target portion 23 in the target T. The surface area of the mark portion 27 is larger than the surface area of the target portion 23. Thereby, in the X-ray generator 1, in the target T, the position information of the mark part 27 which is the position information of the substance different from the substrate 21 can be obtained with certainty. Further, the mark portion 27 is separated so as not to overlap the target portion 23 when viewed from the facing direction A, and the length of the mark portion 27 in the facing direction A is shorter than the length of the target portion 23 in the facing direction A. The intensity of the reflected electrons (absorbed electrons) in the mark portion 27 is different from the intensity of the reflected electrons (absorbed electrons) in the target portion 23, and shows a characteristic difference that it is lower than that of the target portion 23. Thereby, in the X-ray generator 1, the mark part 27 and the target part 23 can be identified. In the X-ray generator 1, the position of the target unit 23 can be specified with reference to the mark unit 27. Therefore, since the X-ray generation apparatus 1 includes the mark portion 27 that is easy to detect at the target T and can be identified from the target portion 23, the target portion 23 can be quickly and accurately identified on the target T.

  In the present embodiment, the length L <b> 2 of the mark portion 27 is shorter than the length L <b> 1 of the target portion 23. When the mark part 27 and the target part 23 are made of materials having the same atomic number, if the mark part 27 and the target part 23 have the same thickness, the amount of reflected electrons emitted (the amount of absorbed electrons) is equivalent. Therefore, it may be difficult to identify the mark portion 27 and the target portion 23. When the X-rays generated by accidentally irradiating the mark part 27 are used, the mark part 27 has a larger surface area than the target part 23. It will be used in a state that does not satisfy the X-ray irradiation conditions. Therefore, the mark portion 27 needs to have a different thickness from the target portion 23.

  Further, when the thickness of the mark portion 27 is increased (for example, larger than 500 nm so as to be equal to the target portion 23), the following problems also occur. That is, in the mark portion 27, for example, when an electron beam EB of about 40 keV is irradiated, 0.3% of that is converted into X-rays and 99.7% is converted into heat. Here, when the mark portion 27 is in contact with the substrate 21 only at the bottom surface, it is difficult to release heat to the outside. Therefore, when the mark portion 27 has a large thickness, heat due to the irradiation of the electron beam EB is stored, and the heat can be destroyed. That is, as described above, the target T may not be satisfied and the target T may be damaged. For example, a desired inspection result cannot be obtained and the target T may become unusable. There is sex. On the other hand, in the present embodiment, since the thickness of the mark portion 27 is smaller than that of the target portion 23, the mark portion 27 and the target portion 23 are reliably identified while preventing damage to the mark portion 27 due to heat. Therefore, desired X-ray irradiation conditions can be obtained stably.

  In the present embodiment, the irradiation field of the electron beam EB is included in the separation region between the mark portion 27 and the target portion 23. That is, the mark portion 27 is disposed outside the focusing area when the target portion 23 is irradiated with the electron beam EB in order to obtain a desired X-ray. Thereby, in the X-ray generator 1, when the electron beam EB is irradiated to the target portion 23, the mark portion 27 is not irradiated with the electron beam EB. Therefore, in X-ray generator 1, it can control that mark part 27 affects X-rays.

  In the present embodiment, the target portion 23 is embedded in the hole H of the substrate 21 and the mark portion 27 is arranged so as not to overlap the target portion 23 when viewed from the facing direction A. I have. By using such a target portion 23, the focal diameter of the generated X-ray is determined using not the irradiation field E of the incident electron beam EB but the outer diameter D1 of the target portion 23 as a dominant element, and the mark portion The influence of X-rays from 27 can be suppressed.

  On the other hand, as a similar structure, a target portion having a large diameter is covered with an electron shield except for a desired focal diameter region, so that only the focal diameter region is exposed to the electron beam. A structure (a structure in which the target portion and the electron shielding portion overlap each other when viewed from the opposite direction) is also conceivable. However, since the electron shield needs to be made of a material that reliably shields electrons, if the electron beam EB enters the electron shield, there is a high possibility that X-rays are generated. Such X-rays are undesirable because they become noise components. However, since the focal region is determined by the electron shield, the electron shield cannot be separated from the focal diameter region in order to suppress the noise component. Therefore, in order to obtain X-rays having a desired focal diameter from the target portion, it is ultimately necessary to narrow down the irradiation field E itself of the electron beam EB according to the focal diameter. However, miniaturization of the irradiation field E of the electron beam EB requires very high control of the electron beam EB, and is very difficult as compared with miniaturization of the target portion. Therefore, it is determined that the structure does not sufficiently cope with miniaturization of the X-ray focus.

  In the above embodiment, the configuration in which the conductive layer 25 is disposed on the first main surface 21a of the substrate 21 and the mark portion 27 is disposed on the conductive layer 25 has been described as an example. The configuration shown in FIG. FIG. 4 is a diagram illustrating a cross-sectional configuration of a target according to another embodiment. As shown in FIG. 4, in the target T, the conductive layer 25 is disposed on the first main surface 21 a and the mark portion 27 of the substrate 21. That is, the mark portion 27 is directly disposed on the first main surface 21 a of the substrate 21. Further, the target portion 23 may be covered with the conductive layer 25, and the mark portion 27 may not be covered with the conductive layer 25.

  In the above embodiment, the configuration in which one target portion 23 is arranged in the target T has been described as an example, but the target T may have a plurality of target portions 23. FIG. 5 is a view of a target according to another embodiment as viewed from the first main surface side of the substrate. As shown in FIG. 5, a plurality of target portions 23 are arranged on the target T, and a plurality (four in FIG. 5A, on the circumference of a virtual circle centering on each target portion 23, 5 (b), three) mark portions 27 are arranged. The mark part 27 is located on the circumference of the virtual circle centering on each target part 23, and by arranging the target parts 23 close to each other, one mark part 27 has a plurality of adjacent target parts 23. It can also serve as a mark for the above.

[Second Embodiment]
Next, the second embodiment will be described. FIG. 6 is a view of the target according to the second embodiment as viewed from the first main surface side of the substrate. FIG. 7 is a diagram showing a cross-sectional configuration taken along line VII-VII in FIG.

  As shown in FIGS. 6 and 7, the target T <b> 1 includes a substrate 21, a target portion 23, a conductive layer 25, and a mark portion 27. In the target T1, the configurations of the substrate 21, the target portion 23, the conductive layer 25, and the mark portion 27 are the same as those in the first embodiment, and the arrangement of the target portion 23 and the mark portion 27 is different from that in the first embodiment.

  A plurality of target units 23 are arranged on the target T1. Specifically, the mark portion 27 is arranged at the center of the virtual circle where the target portion 23 is located, and a plurality of target portions 23 (six in this case) are arranged on the circumference of the virtual circle centering on the mark portion 27. ) Is arranged. The target parts 23 adjacent on the virtual circumference are equally spaced, and the distance between the target parts 23 is, for example, 10 μm or more. The target parts 23 are respectively arranged at positions facing each other with the mark part 27 interposed therebetween. Opposing directions of the pair of target portions 23 intersect each other. The distance between the target portion 23 and the mark portion 27 is, for example, about 10 to 50 μm.

  When specifying the target portion 23 in the target T1, the controller 33 obtains the position information of the mark portion 27, and obtains a virtual circle having a predetermined radius around the mark portion 27. When the controller 33 obtains the virtual circle, it searches the circumference of the virtual circle, position information on the circumference, position information of the target unit 23 set in the target T1, and intensity of reflected electrons (absorbed electrons). Based on the above, the position of the target unit 23 is specified. Alternatively, the position of the target unit 23 may be specified by predicting the position of the target unit 23 from the position information of the mark unit 27, and performing a precise rescan at a low speed starting from the mark unit 27.

  In the above embodiment, the configuration in which the conductive layer 25 is disposed on the first main surface 21a of the substrate 21 and the mark portion 27 is disposed on the conductive layer 25 has been described as an example. The configuration shown in FIG. FIG. 8 is a diagram illustrating a cross-sectional configuration of a target according to another embodiment. As shown in FIG. 8, in the target T <b> 1, the conductive layer 25 is disposed on the first main surface 21 a and the mark portion 27 of the substrate 21. That is, the mark portion 27 is directly disposed on the first main surface 21 a of the substrate 21. Further, the target portion 23 may be covered with the conductive layer 25, and the mark portion 27 may not be covered with the conductive layer 25.

  In the above embodiment, the configuration in which one target portion including the target portion 23 and the mark portion 27 is disposed on the target T1 has been described as an example. However, a plurality of target portions may be disposed in the target T1. FIG. 9 is a view of a target according to another embodiment as viewed from the first main surface side of the substrate. As shown in FIG. 9, the target T <b> 1 is provided with a plurality of mark portions 27, and the plurality of target portions 23 are arranged on the circumference of an imaginary circle centering on each mark portion 27.

  In the above-described embodiment, the configuration in which the mark portion 27 has a substantially circular shape when viewed from the facing direction A of the first and second main surfaces 21a and 21b has been described as an example. However, the mark portion 27 has other shapes. There may be. FIG. 10 is a view of a target according to another embodiment as viewed from the first main surface side of the substrate. As shown in FIG. 10, the mark portion 27 has a polygonal shape, and here has a hexagonal shape. Each of the top portions (vertices) of the mark portion 27 faces the direction in which the target portion 23 is arranged. In other words, the target portion 23 is disposed on an extension line of the top portion of the mark portion 27. Thereby, in the X-ray generator 1, when the positional information of the mark part 27 is acquired, the target part 23 can be identified more quickly and accurately by scanning the direction of the vertex of the mark part 27.

[Third Embodiment]
Subsequently, the third embodiment will be described. FIG. 11 is a view of the target according to the third embodiment as viewed from the first main surface side of the substrate. 12 is a diagram showing a cross-sectional configuration taken along line XII-XII in FIG.

  As shown in FIGS. 11 and 12, the target T <b> 2 has a substrate 21, a target portion 23, a conductive layer 25, and a mark portion 35. In the target T2, the configuration of the substrate 21, the target portion 23, and the conductive layer 25 is the same as that in the first embodiment, and the configuration of the mark portion 35 is different from that in the first embodiment.

  The mark portion 35 is disposed on the conductive layer 25. The mark portion 35 is disposed on substantially the entire surface of the substrate 21 on the first main surface 21 a side, and an opening 35 a is formed along a virtual circle centered on the target portion 23. The opening 35a of the mark portion 35 has an inner diameter of about 10 to 50 μm.

  When the target portion 23 is specified in the target T2, the controller 33 searches the opening portion 35a of the mark portion 27 and detects the edge (opening end) of the opening portion 35a. When detecting the edge of the opening 35a, the controller 33 obtains the center of the opening 35a. When the controller 33 obtains the center of the opening 35a, based on the position information of the center, the position information of the target 23 set in the target T2, and the intensity of the reflected electrons (absorbed electrons), Identify the location.

  In the above embodiment, the configuration in which the conductive layer 25 is disposed on the first main surface 21a of the substrate 21 and the mark portion 35 is disposed on the conductive layer 25 has been described as an example. The configuration shown in FIG. FIG. 13 is a diagram illustrating a cross-sectional configuration of a target according to another embodiment. As shown in FIG. 13, in the target T <b> 2, the conductive layer 25 is disposed on the first main surface 21 a, the target portion 23, and the mark portion 35 of the substrate 21. That is, the mark portion 35 is directly disposed on the first main surface 21 a of the substrate 21. When the mark portion 35 covers substantially the entire first main surface 21a of the substrate 21, the conductive layer 25 may cover only the opening portion 35a. In this case, the electron incident surface of the target portion 23 may be covered. It may be exposed.

  In the above embodiment, the configuration in which one target portion 23 is arranged on the target T2 has been described as an example. However, a plurality of target portions 23 may be arranged on the target T2. FIG. 14 is a view of a target according to another embodiment as viewed from the first main surface side of the substrate. As shown in FIG. 14, the target T <b> 2 is provided with a plurality of target portions 23, and an opening 35 a is formed along the circumference of an imaginary circle centering on each target portion 23.

  In the above embodiment, the opening 35a has a substantially circular shape, but the opening may have a polygonal shape.

[Fourth Embodiment]
Subsequently, a fourth embodiment will be described. FIG. 15 is a view of the target according to the fourth embodiment as viewed from the first main surface side of the substrate. 16 is a diagram showing a cross-sectional configuration taken along line XVI-XVI in FIG.

  As shown in FIGS. 15 and 16, the target T <b> 3 has a substrate 21, a target portion 23, a conductive layer 25, and a mark portion 37. In the target T3, the configurations of the substrate 21, the target portion 23, and the conductive layer 25 are the same as those in the first embodiment, and the configuration of the mark portion 37 is different from that in the first embodiment.

  The mark portion 37 is disposed on the conductive layer 25. The mark portion 37 has a rectangular frame shape when viewed from the first main surface 21 a side of the substrate 21. That is, the target portion 23 is surrounded by the mark portion 37 and is located at the center of the mark portion 37. The distance between the mark portion 37 and the target portion 23 is, for example, about 10 to 50 μm. The width of the mark part 37 is, for example, 3 to 10 μm.

  When the target portion 23 is specified in the target T <b> 3, when the controller 33 acquires the position information of the mark portion 37, the controller 33 detects an edge inside the mark portion 37. When the controller 33 detects the inner edge of the mark portion 37, the controller 33 obtains the center of the mark portion 37. When the controller 33 obtains the center of the mark portion 37, the controller 33 determines the position of the target portion 23 based on the position information of the center, the position information of the target portion 23 set in the target T3, and the intensity of the reflected electrons (absorbed electrons). Identify the location.

  In the above embodiment, the configuration in which the conductive layer 25 is disposed on the first main surface 21a of the substrate 21 and the mark portion 37 is disposed on the conductive layer 25 has been described as an example. The configuration shown in FIG. FIG. 17 is a diagram illustrating a cross-sectional configuration of a target according to another embodiment. As shown in FIG. 17, in the target T <b> 3, the conductive layer 25 is disposed on the first main surface 21 a, the target portion 23, and the mark portion 37 of the substrate 21. That is, the mark portion 37 is directly disposed on the first main surface 21 a of the substrate 21. Further, the electron incident surface and the mark portion 27 of the target portion 23 may not be covered with the conductive layer 25.

  In the above embodiment, the configuration in which one target portion 23 is arranged on the target T3 has been described as an example. However, in the target T3, a plurality of target portions 23 may be arranged. FIG. 18 is a view of a target according to another embodiment as viewed from the first main surface side of the substrate. As shown in FIG. 18, the target T <b> 3 is provided with a plurality of target parts 23, and a frame-shaped mark part 37 is arranged around each target part 23. The mark portion 37 may have a rectangular shape as shown in FIG. 18A, or may have a circular shape as shown in FIG.

  The preferred embodiments of the present invention have been described above. However, the present invention is not necessarily limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

  In the above embodiment, the substrate, the target portion, and the mark portion are determined based on the intensity of reflected electrons and absorbed electrons of the target, but the target portion based on the intensity and energy band of X-rays generated from the target, and The mark portion may be determined. Further, the diameter of the electron beam EB at the time of scanning may be larger than the diameter of the electron beam EB at the time of X-ray generation. In this case, for example, defocusing from the state at the time of X-ray generation can be considered, and the scanning time can be shortened. Further, the intensity of the electron beam EB at the time of scanning may be made smaller than that at the time of X-ray generation. In this case, the target T can be protected by suppressing the influence of heat or the like due to the electron beam EB irradiation during scanning. Further, the mark portion 27 may be formed so as to be embedded in the substrate 21 similarly to the target portion 23, and the shape of the target portion 23 is not limited to the cylindrical shape, and may be other shapes.

  DESCRIPTION OF SYMBOLS 1 ... X-ray generator, 3 ... Electron gun, 7 ... Coil part (focusing part), 9 ... Coil part (scanning part), 21 ... Board | substrate, 21a ... 1st main surface, 21b ... 2nd main surface, 23 ... Target part, 27, 35, 37 ... mark part, EB ... electron beam, H ... hole, T1, T2, T3 ... target.

Claims (5)

A substrate made of an insulating material, having a first main surface and a second main surface facing each other, and having a hole extending in the opposing direction of the first and second main surfaces;
An X-ray generation target comprising a target part made of a metal material and embedded in the hole,
It is made of a metal material, and includes a mark portion that is located on the first main surface side and is spaced apart so as not to overlap the target portion when viewed from the facing direction,
When viewed from the facing direction, the surface area of the mark portion is larger than the surface area of the target portion,
An X-ray generation target, wherein a length dimension of the mark portion in the facing direction is smaller than a length dimension of the target portion.   The target for X-ray generation according to claim 1, wherein the mark portion is arranged around the target portion.   The target for X-ray generation according to claim 1, wherein the mark portion surrounds the target portion.   The target for X-ray generation according to claim 1, wherein a plurality of the mark portions are arranged around the target portion. The target for X-ray generation as described in any one of Claims 1-4,
An electron gun for generating an electron beam incident on a target portion of the X-ray generation target;
A focusing section for focusing the electron beam;
A scanning unit for scanning the electron beam on the X-ray generation target;
A controller for controlling the converging unit and the scanning unit,
X-rays characterized in that the mark portion is arranged in a scanning region of the electron beam by the scanning portion and outside the focusing region of the electron beam focused on the target portion by the focusing portion. Generator.

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