Patent Application
20250044465
The present invention relates to a radiation detection apparatus, a manufacturing method thereof, and a system.
A radiation detection apparatus having a semiconductor layer that converts radiation into a charge has been proposed. In some radiation detection apparatuses, a large sensor surface is formed by arranging a plurality of sensor units in a one- or two-dimensional array. Japanese Patent Laid-Open No. 2012-37281 describes a radiation detection apparatus in which substrates on which semiconductor elements are mounted are inserted into a slit member to align a plurality of the substrates. Japanese Patent Laid-Open No. 2008-298556 describes a radiation detector in which an adhesive or a bonding agent that absorbs X-rays is disposed in a gap between adjacent ones of a plurality of modules in which a plurality of X-ray detection elements are arranged one- or two-dimensionally. Japanese Patent Laid-Open No. 2003-329778 describes a technique for coating each side surface of a plurality of X-ray detection elements with an insulating material. Variations in the heights of the plurality of semiconductor layers that detect radiation can reduce the accuracy of radiation detection by the radiation detection apparatus. In addition, radiation entering the gaps between the plurality of semiconductor layers is not detected, and thus if the gaps are large, the accuracy of the radiation detection by the radiation detection apparatus can drop.
Some aspects of the present disclosure provide a technique for improving the accuracy of radiation detection. According to an embodiment, a radiation detection apparatus comprising: a plurality of unit structures each having a semiconductor layer that converts radiation into a charge, the unit structures being arranged to form an array; and a coupling member that couples two of the unit structures adjacent to each other in the array, wherein the coupling member is formed from a material capable of being used as a vapor deposition material, and each of the plurality of unit structures further includes a mounting board on which is mounted an integrated circuit that processes a signal based on the charge obtained by the semiconductor layer is provided.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Hereinafter, embodiments will be described in detail with reference to the attached drawings. Note, the following embodiments are not intended to limit the scope of the claimed invention. Multiple features are described in the embodiments, but limitation is not made to an invention that requires all such features, and multiple such features may be combined as appropriate. Furthermore, in the attached drawings, the same reference numerals are given to the same or similar configurations, and redundant description thereof is omitted.
In addition to α-rays, β-rays, γ-rays, and the like, which are beams created by particles (including photons) emitted as a result of radiation decay, “radiation” in the following descriptions can also include beams with the equivalent or higher energy, such as X-rays, particle beams, cosmic rays, and the like, for example. In this application, photons such as X-rays and γ-rays and particles such as β-rays and α-rays may be described collectively as “radiation photons”.
An example of the configuration of a computed tomography (CT) apparatus 100 according to some embodiments will be described with reference to the block diagram in
The CT apparatus 100 may be an apparatus capable of performing photon counting CT. In other words, the CT apparatus 100 described in the following embodiment may be an apparatus capable of reconstructing CT image data with a high SN ratio by counting radiation transmitted through a subject using a photon counting-type radiation detection apparatus 104. The radiation detection apparatus 104 described in the following embodiment may also be a direct conversion-type detector that directly converts radiation photons into a charge proportional to the energy thereof.
The radiation generation unit 101 emits radiation toward the radiation detection apparatus 104. The radiation generation unit 101 is constituted by, for example, a vacuum tube that generates X-rays. A high voltage and filament current are supplied to the vacuum tube of the radiation generation unit 101 from the high voltage generation device 107. X-rays are produced when thermoelectrons are emitted from a cathode (filament) toward an anode (target). The wedge 102 is a filter that adjusts the amount of radiation 121 emitted from the radiation generation unit 101. The wedge 102 attenuates the radiation dose such that the radiation 121 emitted from the radiation generation unit 101 to a subject 120 has a predetermined distribution. The collimator 103 is constituted by a lead plate or the like that narrows the irradiation range of radiation transmitted through wedge 102. The radiation 121 generated by the radiation generation unit 101 is formed into a cone beam shape through the collimator 103 and emitted onto the subject 120 on the top plate 105.
The radiation detection apparatus 104 detects the radiation 121 passing through the subject 120 from the radiation generation unit 101, and outputs a signal corresponding to the radiation dose to the DAS 108. The subject 120 may be a living organism (e.g., a human or an animal), or an inanimate object.
Each time a radiation photon is incident on the radiation detection apparatus 104, a signal through which the energy value of the radiation photon can be measured may be output. Radiation photons are, for example, radiation photons emitted from the radiation generation unit 101 and transmitted through the subject 120. The radiation detection apparatus 104 has a plurality of detection elements that output one pulse of an electrical signal (an analog signal) each time a radiation photon is incident. By counting the number of electrical signals (pulses), the number of radiation photons incident on each detection element can be counted. Additionally, by performing arithmetic processing on the signal, the energy value of the radiation photon that produced the output of the signal can be measured.
The detection element mentioned above may be, for example, a semiconductor detection element such as CdTe (cadmium telluride) or CdZnTe (cadmium zinc telluride), with electrodes disposed thereon. In other words, the radiation detection apparatus 104 is a direct conversion-type detector that converts incident radiation photons directly into electrical signals. The radiation detection apparatus 104 has a plurality of the stated detection elements, as well as a plurality of Application Specific Integrated Circuits (ASICs) which are connected to the detection elements and which count the radiation photons detected by the corresponding detection elements. Each ASIC counts the number of radiation photons incident on the detection element by distinguishing the individual charges output by the detection element. The ASIC also measures the energy of the counted X-ray photons by performing arithmetic processing based on the magnitudes of the individual charges. Furthermore, the ASIC outputs the result of counting the radiation photons as digital data to the DAS 108.
The DAS 108 generates detection data based on the results of the counting processing input from the radiation detection apparatus 104. The detection data is a sinogram, for example. The sinogram is data that arranges the results of the processing for counting the photons incident on each detection element at each location of the radiation generation unit 101. The sinogram is data in which the results of the counting processing are arranged in a two-dimensional Cartesian coordinate system that takes the view direction and the channel direction as axes. The DAS 108 generates sinograms, for example, in units of columns in the slice direction in the radiation detection apparatus 104. The result of the counting processing is data that allocates a number of radiation photons for each of energy bins. For example, the DAS 108 counts photons derived from the radiation emitted from the radiation generation unit 101 and transmitted through the subject 120 (radiation photons) and distinguishes the energy of the counted radiation photons, which is the result of the counting processing. The DAS 108 is implemented by a processor, for example.
The rotating frame 106 is circular and capable of rotating. The radiation generation unit 101 (the wedge 102, the collimator 103) and the radiation detection apparatus 104 are disposed within the rotating frame 106 on opposite sides of each other with respect to the top plate 105. The radiation generation unit 101 and the radiation detection apparatus 104 are capable of rotating with the rotating frame 106.
The high voltage generation device 107 includes a booster circuit, and outputs a high voltage to the radiation generation unit 101. For example, the high voltage generation device 107 has electrical circuits such as a transformer, a rectifier, and the like, a high voltage generation unit that generates a high voltage to be applied to the radiation generation unit 101, and a radiation control unit that controls an output voltage according to the radiation generated by the radiation generation unit 101. The high voltage generation unit may be a transformer type or an inverter type. The high voltage generation device 107 may be provided in the rotating frame 106, or in a fixed frame (not shown). The DAS 108 includes an amplification circuit and an analog/digital (A/D) conversion circuit, and outputs signals from the radiation detection apparatus 104 as digital data to the signal processing unit 109.
The signal processing unit 109 processes signals output from the radiation detection apparatus 104. The signal processing unit 109 may include a central processing unit (CPU), a read-only memory (ROM), and a random access memory (RAM). The display unit 110 includes a flat-panel display device or the like, and is capable of displaying radiological images. The control unit 111 includes a CPU, a ROM, a RAM, and the like, and controls the operations of the CT apparatus 100 as a whole. For example, the control unit 111 has processing circuitry including a CPU and the like, and drive mechanisms such as motors and actuators. The control unit 111 receives input signals from an input interface and controls the operations of a gantry and a subject table. For example, the control unit 111 controls the rotation of the rotating frame 106, the tilt of the gantry, and the movement of the subject table and the top panel. To give one example, as control that tilts the gantry, the control unit 111 rotates the rotating frame 106 about an axis parallel to an X-axis direction according to tilt angle information that is input. The control unit 111 may be provided in the gantry or in a console device.
The input interface accepts various input operations from an operator, converts the accepted input operations into electrical signals, and outputs the electrical signals to the control unit 111. For example, the input interface accepts, from the operator, input operations such as reconstruction conditions for reconstructing CT image data, image processing conditions for generating a post-processing image from the CT image data, and the like. For example, the input interface is realized by a mouse, a keyboard, a trackball, switches, buttons, a joystick, a touchpad through which input operations are made by touching an operating surface, a touchscreen in which a display screen and a touchpad are integrated, a non-contact input circuit that uses a photosensor, an audio input circuit, or the like. The input interface may be provided in the gantry. Alternatively, the input interface may be constituted by a tablet terminal or the like capable of communicating wirelessly with the main body of the console device. Furthermore, the input interface is not limited to an interface that includes physical operating components such as a mouse, a keyboard, or the like. For example, electrical signal processing circuitry that receives an electrical signal corresponding to an input operation from an external input device provided separate from the console device, and outputs the electrical signal to the control unit 111, is also an example of the input interface.
The signal processing unit 109 may have a pre-processing function. Using the pre-processing function, the signal processing unit 109 can generate projection data by performing pre-processing such as logarithmic conversion processing, offset correction processing, inter-channel sensitivity correction processing, beam hardening correction, and the like on the detection data output from the DAS 108. The signal processing unit 109 may also have a reconstruction processing function. Using the reconstruction processing function, the signal processing unit 109 can generate CT image data by performing reconstruction processing using filtered back projection, a successive approximation reconstruction, or the like on the projection data generated by the pre-processing function. Additionally, using the reconstruction processing function, the signal processing unit 109 can store the reconstructed CT image data in a memory.
The projection data generated from the counting results obtained in photon counting CT contains information on the energy of X-rays attenuated by passing through the subject 120. As such, the signal processing unit 109 can reconstruct the CT image data of a specific energy component, for example, by using the reconstruction processing function. The signal processing unit 109 can also reconstruct the CT image data of each of a plurality of energy components, for example, by using the reconstruction processing function. Furthermore, using the reconstruction processing function, the signal processing unit 109 can, for example, assign a color according to the energy component to each pixel in CT image data indicating energy components, and generate image data in which a plurality of pieces of CT image data colored according to the energy components are superimposed on each other. The signal processing unit 109 can also generate image data through which a substance can be identified using, for example, the K-absorption edge unique to that substance, using the reconstruction processing function. Monochromatic X-ray image data, density image data, effective atomic number image data, and the like can be given as other types of image data generated by the signal processing unit 109 using the reconstruction processing function.
To reconstruct CT image data, 360° of projection data around the entire periphery of the subject is required, and for the half-scan method, projection data for 180° plus the fan angle is required. Either reconstruction method can be applied to the present embodiment. To simplify the descriptions, the following will assume that a reconstruction method which reconstructs the data using 360° of projection data around the entire periphery of the subject (full-scan reconstruction) is used.
The signal processing unit 109 may have an image processing function. Using the image processing function, the signal processing unit 109 can use a publicly-known method to convert the CT image data generated by the reconstruction processing function into image data such as a tomographic image of a desired cross-section, a three-dimensional image generated through rendering processing, or the like based on an input operation received from the operator through the input interface. Additionally, using the image processing function, the signal processing unit 109 can store the converted image data in a memory.
The control unit 111 may have a scan control function. The control unit 111 controls CT scanning performed through the gantry using a scan control function. For example, the control unit 111 controls processing for collecting counting results in the gantry by controlling the operations of the high voltage generation device 107, the radiation detection apparatus 104, the DAS 108, and a subject table driving device, using the scan control function. In one example, the control unit 111 controls processing for collecting projection data in imaging that collects positioning images (scanography images) and main imaging (scanning) that collects images for diagnosis, respectively, using the scan control function. The control unit 111 may have a display control function. The control unit 111 can control various types of image data stored in the memory to be displayed in the display unit 110, which is a display or the like, using the display control function.
An example of the configuration of the radiation detection apparatus 104 will be described with reference to the perspective view in
An example of the configuration of the sensor module 202 will be described with reference to the perspective view in
The sensor unit 301 generates a signal according to radiation incident on the sensor unit 301. The sensor unit 301 and the circuit board 304 are connected by a cable (not shown; for example, a flexible cable). The signal generated by the sensor unit 301 is read out to the DAS 108 through the circuit board 304. The plurality of sensor units 301 are arranged in the direction in which the frame 303 extends. In the example illustrated in
The frame 303 is a rigid member for attaching the sensor unit 301. The frame 303 may be called a “mounting frame”. The frame 303 may be formed from a metal, for example. The frame 303 functions as a support member that supports the sensor unit 301. The circuit board 304 is attached to the frame 303. The plurality of sensor units 301 and the circuit board 304 are located on opposite sides of the frame 303. The frame 303 is fixed to the base 201. For example, the frame 303 may be fixed to the base 201 mechanically using fasteners such as screws, or may be fixed to the base 201 chemically using an adhesive.
A substrate 305 is disposed in a position that covers the plurality of sensor units 301 provided in the sensor module 202.
The substrate 305 is fixed to the frame 303. The substrate 305 may be fixed directly or indirectly to the frame 303. For example, the substrate 305 may be fixed to the frame 303 indirectly by fixing both the frame 303 and the substrate 305 to the base 201.
The heat dissipation member 302 is located between the frame 303 and a bottom surface 408 of each of the plurality of sensor units 301a to 301d. A single heat dissipation member 302 may be disposed in common for the plurality of sensor units 301. Instead, however, an individual heat dissipation member 302 may be disposed for each of the plurality of sensor units 301. For example, the heat dissipation member 302 may be wider than the bottom surfaces of the sensor units 301 in the short side direction of the frame 303. The heat dissipation member 302 transfers heat produced by the sensor units 301 to the frame 303. The heat dissipation member 302 may be formed from a metal, for example. However, the sensor module 202 need not include the heat dissipation member 302. In this case, heat produced by the sensor units 301 is transferred directly to the frame 303.
An example of the configuration of the sensor unit 301 will be described with reference to the cross-sectional view in
The semiconductor layer 402 converts radiation into a charge. The top surface 401 of the semiconductor layer 402 is located on the side where the radiation 121 is incident. In the example in
The semiconductor layer 402 may be a single-crystal substrate formed from a semiconductor that directly converts radiation into a charge, such as cadmium zinc telluride (CdZnTe) or cadmium telluride (CdTe). The semiconductor layer 402 may be a single-crystal substrate formed from a semiconductor such as silicon (Si), lead iodide (PbI2), mercury iodide (HgI2), bismuth iodide (BiI3), thallium bromide (TlBr), or the like.
The top surface 401 of the sensor unit 301 is covered by the substrate 305. The entire top surface 401 of the sensor unit 301 may be covered by the substrate 305, or only a part of the top surface 401 of the sensor unit 301 may be covered by the substrate 305.
The top surface 401 of the sensor unit 301 (the top surface of the semiconductor layer 402, in the example in
The substrate 305 may include an insulating layer 411 and the conductive layer 412. The substrate 305 may also be formed from a thin film or the like. The conductive layer 412 faces the top surface 401 of the sensor unit 301. The conductive layer 412 may be in contact with the top surface 401 of the sensor unit 301. The conductive layer 412 may be formed from a metal such as gold, silver, copper, or aluminum, an alloy, or the like, for example. The insulating layer 411 covers the conductive layer 412. The insulating layer 411 may be formed from, for example, carbon-fiber-reinforced plastic (CFRP), amorphous carbon, polyimide film, or the like.
The conductive layer 412 may be used to apply a voltage to the semiconductor layer 402. When used in this manner, the conductive layer 412 may be in contact with the semiconductor layer 402, or may be fixed to the semiconductor layer 402 using a conductive adhesive.
When the conductive layer 412 is used to apply a voltage to the semiconductor layer 402, each sensor unit 301 need not include a separate electrode for applying the voltage to the semiconductor layer 402, as illustrated in
Electrodes formed on the bottom surface of the semiconductor layer 402 and the electrodes formed on the top surface of the interposer 404 are electrically and physically connected to each other by bumps 403. Individual electrodes are formed on the bottom surface of the semiconductor layer 402 so as to correspond to pixels of the sensor unit 301. Electrodes formed on the bottom surface of the interposer 404 and the electrodes formed on the top surface of the integrated circuit 406 are electrically and physically connected to each other by bumps 405. The bumps 403 and 405 are formed from solder, for example. Anisotropic conductive films (ACFs) may be used instead of the bumps 403 and 405. The interposer 404 relays signals between the semiconductor layer 402 and the integrated circuit 406. The interposer 404 may be omitted.
The integrated circuit 406 is attached to the mounting board 407. The integrated circuit 406 may be an energy dispersive counting circuit (ERCE). For example, the integrated circuit 406 may have a function for counting electrical pulses produced when radiation photons are incident on the semiconductor layer 402. Instead, however, the integrated circuit 406 may read out a voltage according to the charge accumulated in the semiconductor layer 402 from the semiconductor layer 402.
Two sensor units 301 adjacent to each other in the array among the plurality of sensor units 301 are coupled to each other by a coupling member 410. As will be described later, the coupling member 410 is formed by vapor deposition. In other words, the coupling member 410 is formed from a material capable of being used as a vapor deposition material. An example of such a material will be described later. By forming the coupling member 410 by vapor deposition, the sensor units 301 can be more firmly coupled to each other, even when the coupling member 410 is thin, than when the coupling member 410 is formed from an adhesive or the like. As such, the gap between the two adjacent sensor units 301 (in particular, the gap between the two adjacent semiconductor layers 402) can be reduced. In addition, coupling the two adjacent sensor units 301 to each other makes it easier to maintain a state in which the gaps between these sensor units 301 are reduced. When the gap between the two adjacent sensor units 301 is large, the gap between the adjacent semiconductor layers 402 is also large, which increases the amount of radiation that cannot be detected. Reducing the gap between the two adjacent sensor units 301 as per the configuration illustrated in
In the configuration illustrated in
In the configuration illustrated in
The coupling member 410 fills the space between the semiconductor layers 402 and the interposers 404 of the sensor units 301. This makes it possible to suppress shorting between the plurality of bumps 403. The coupling member 410 also fills the space between the interposers 404 and the mounting boards 407 of the sensor units 301. This makes it possible to suppress shorting between the plurality of bumps 405. The coupling member 410 covers the side surfaces of the semiconductor layer 402 and at least a part of the bottom surface of the semiconductor layer 402 in each of the sensor units 301. The coupling member 410 covers at least a part of the top surface of the interposer 404, the side surfaces of the interposer 404, and at least a part of the bottom surface of the interposer 404 in each of the sensor units 301. The coupling member 410 covers at least a part of the top surface of the mounting board 407 and the side surfaces of the mounting board 407 in each of the sensor units 301. The coupling member 410 covers the top surface of the substrate 305, the side surfaces of the substrate 305, and the parts of a base surface of the substrate 305 that do not face the sensor unit 301.
As illustrated in
In the example in
The functions of the heat dissipation member 302 will be described next. The thicknesses of the plurality of sensor units 301a to 301d (i.e., the distances between the top surfaces and the bottom surfaces) vary due to manufacturing error and the like. As such, attaching the plurality of sensor units 301a to 301d directly to the flat surface of the frame 303 may cause the heights of the semiconductor layers 402 (e.g., the distances from the frame 303) to vary. The heat dissipation member 302 may therefore be a member which is elastic so as to be capable of absorbing such variations.
When a single substrate 305 is used in common for the plurality of sensor modules 202, the substrate 305 can be curved in accordance with the shape of the base 201. In this case, the bottom surface of the substrate 305 may be a smooth curved surface. The bottom surface of the substrate 305 has a smooth surface at the parts in contact with the top surfaces 401 of the plurality of sensor units 301, and the other parts need not be smooth (e.g., may have an opening).
The substrate 305 may have a grid for reducing scattered rays. The number of components of the radiation detection apparatus 104 can be reduced by having the substrate 305 function both to align the sensor units 301 and reduce scattered rays.
A variation on the configuration of the radiation detection apparatus 104 illustrated in
Even with the configuration illustrated in
Another variation on the configuration of the radiation detection apparatus 104 illustrated in
Even with the configuration illustrated in
Another variation on the configuration of the radiation detection apparatus 104 illustrated in
The plurality of semiconductor layers 402 included in a single sensor unit 301 are disposed so as to form an array. The plurality of semiconductor layers 402 may form a one-dimensional array, or may form a two-dimensional array. Furthermore, a three-dimensional array may be formed by layering two or more semiconductor layers 402 in what is the vertical direction in the figure. Although the example illustrated in
In the configuration illustrated in
The two semiconductor layers 402 adjacent to each other in the array, among the plurality of semiconductor layers 402, are coupled by the coupling member 410. Similar to the configuration illustrated in
A variation on the configuration of the radiation detection apparatus 104 illustrated in
Another variation on the configuration of the radiation detection apparatus 104 illustrated in
A method for manufacturing the radiation detection apparatus 104 according to some embodiments will be described with reference to
The plurality of sensor units 301 are disposed on a temporary fixing member 1002 so as to form an array. The substrate 305 is disposed on the plurality of sensor units 301. The substrate 305 may be coupled to each of the plurality of sensor units 301. The plurality of sensor units 301 may be fixed to the temporary fixing member 1002. The temporary fixing member 1002 may be an adhesive sheet, or may be an adsorption stage. Furthermore, the positions of the plurality of sensor units 301 relative to each other may be fixed by compressing the outer peripheries of the plurality of sensor units 301 inward. Disposing the plurality of sensor units 301 on the temporary fixing member 1002 makes the positions of the bottom surfaces of the plurality of sensor units 301 uniform. The temporary fixing member 1002 also functions as a mask during vapor deposition.
A vessel 1003 that holds vapor deposition material is also installed within the chamber 1001. As illustrated in
An example of the vapor deposition material used for the vapor deposition will be described. The vapor deposition material may include one or more insulative organic materials, e.g., parylene, polyethylene, polytetrafluoroethylene, polyimide, polyamide, polyurea, and polyurethane. Parylene, polyimide, polyamide, polyurea, and polyurethane may be used in vapor deposition polymerization. Polyethylene and polytetrafluoroethylene may be used in physical vapor deposition. The coupling member 410 formed from such a material may be elastic. The elastic coupling member 410 may also function as a buffer material against heat, vibrations, and the like for the plurality of sensor units 301. Of these materials, parylene, for example, can be used for vapor deposition even when the work to be coated is at normal temperature.
The vapor deposition material may include one or more insulative inorganic materials, e.g., silicon oxide (SiO2), aluminum oxide (Al2O3), and silicon nitride (SiN). These materials may be used in sputter deposition. The coupling member 410 formed from such a material may be rigid.
The vapor deposition material may include one or more insulative organic materials, e.g., TEOS (rational formula: Si(OC2H5)4), TMB (rational formula: B(OCH3)3), TEB (rational formula: B(OC2H5)3), TMP (rational formula: P(OCH3)3), TMOP (rational formula: PO(OCH3)3), TEOP (rational formula: PO(OC2H5)3), TriMS (rational formula: SiH(CH3)3), and MTMS (rational formula: CH3Si(OCH3)3). These materials may be used in chemical vapor deposition.
After the process illustrated in
In the method illustrated in
Next, a method for manufacturing the radiation detection apparatus 104 illustrated in
The plurality of semiconductor layers 402 are disposed on the temporary fixing member 1002 so as to form an array. The plurality of semiconductor layers 402 may be fixed to the temporary fixing member 1002. The positions of the plurality of semiconductor layers 402 relative to each other may be fixed by compressing the outer peripheries of the plurality of semiconductor layers 402 inward. Disposing the plurality of semiconductor layers 402 on the temporary fixing member 1002 makes the positions of the bottom surfaces of the plurality of semiconductor layers 402 uniform. The temporary fixing member 1002 also functions as a mask during vapor deposition.
The vessel 1003 that holds vapor deposition material is also installed within the chamber 1001. As illustrated in
After the process illustrated in
The interposer 404 and the mounting board 407 are then formed. The interposer 404 and the mounting board 407 may be formed before the plurality of semiconductor layers 402 are coupled to the substrate 305. As illustrated in
In the method illustrated in
A variation on the manufacturing method illustrated in
In the variation illustrated in
In the variation illustrated in
Another example of the configuration of the sensor unit 301 will be described next with reference to the cross-sectional view in
Variation in the heights of the top surfaces 401 of the plurality of sensor units 301 can be suppressed by bringing each of the plurality of sensor units 301 into contact with the substrate 305 provided in common for the plurality of sensor units 301. Additionally, the state in which variation in the heights of the top surfaces 401 of the plurality of sensor units 301 is suppressed becomes easier to maintain by bonding each of the plurality of sensor units 301 to the substrate 305 provided in common for the plurality of sensor units 301. The height of the top surface 401 may be a height relative to the bottom surface of the substrate 305. If the heights of the top surfaces 401 vary, for example, radiation directed diagonally toward one sensor unit 301 may be detected by another sensor unit 301. Suppressing variation in the heights of the top surfaces 401 of the plurality of sensor units 301 enables highly-precise radiation detection, which improves the image quality of the radiological image.
Two of the sensor units 301 adjacent to each other in the array, among the plurality of sensor units 301, may be in contact with each other. For example, the semiconductor layers 402 of the two adjacent sensor units 301 may be in contact with each other. The interposers 404 of the two adjacent sensor units 301 may be in contact with each other. The mounting boards 407 of the two adjacent sensor units 301 may be in contact with each other. In the example in
Having the two adjacent sensor units 301 in contact with each other can reduce gaps between these sensor units 301. In addition, bonding the two adjacent sensor units 301 to each other makes it easier to maintain a state in which the gaps between these sensor units 301 are reduced. When the gap between the two adjacent sensor units 301 is large, the gap between the adjacent semiconductor layers 402 is also large, which increases the amount of radiation that cannot be detected. Reducing the gap between the two adjacent sensor units 301 as per the configuration illustrated in
The conductive layer 412 may be used to apply a voltage to the semiconductor layer 402. When used in this manner, the conductive layer 412 may be in contact with the semiconductor layer 402, and in particular, may be bonded thereto. When the conductive layer 412 and the semiconductor layer 402 are bonded to each other by solid-phase bonding (e.g., normal temperature bonding), the electrical resistance of the current path between the conductive layer 412 and the semiconductor layer 402 is lower than when a conductive adhesive is used for the coupling.
A variation on the configuration of the radiation detection apparatus 104 illustrated in
As illustrated in
The sensor unit 301 (the semiconductor layer 402, in the example in
The configuration illustrated in
Another variation on the configuration of the radiation detection apparatus 104 illustrated in
The plurality of semiconductor layers 402 included in a single sensor unit 301 are disposed so as to form an array. The plurality of semiconductor layers 402 may form a one-dimensional array, or may form a two-dimensional array. Furthermore, a three-dimensional array may be formed by layering two or more semiconductor layers 402 in what is the vertical direction in the figure. Although the example illustrated in
In the configuration illustrated in
Two of the semiconductor layers 402 adjacent to each other in the array, among the plurality of semiconductor layers 402, may be in contact with each other. The two adjacent semiconductor layers 402 may or may not be bonded to each other at a contact surface. When the two adjacent semiconductor layers 402 are bonded to each other, the bonding may be realized by solid-phase bonding, as will be described later. In this case, the two adjacent semiconductor layers 402 are bonded to each other by the cohesive force between atoms.
In the configuration illustrated in
A method for manufacturing the radiation detection apparatus 104 according to some embodiments will be described with reference to
Solid-phase bonding is a method in which two members are bonded to each other in a solid phase state (i.e., the members are not melted and instead remain solid) by pressurization, or by pressurization while being heated. Other methods of solid-phase bonding include fusion bonding (arc welding, laser welding, resistance welding), liquid-solid reactive bonding (brazing, liquid-phase diffusion bonding, thermal spraying, adhesion). Compared to these other methods, solid-phase bonding has the advantages that the members themselves do not reach high temperatures and do not dissolve; residual stress produced by differences in the thermal expansion coefficients of the members and the bonding material (wax, thermal spraying material, adhesive, or the like) is low; the crystalline state is less likely to change or weaken due to high temperatures; and the like. In particular, because there is no adhesive between the members, solid-phase bonding enables the gaps between the members to be made far narrower than in bonding using adhesive, which is commonly used.
Solid-phase bonding is performed by diffusing and rearranging the atoms of the two members. Solid-phase bonding can include two methods. One is a method in which two members are brought into contact with each other and bonded, and the other is a method in which two members are bonded using a metal inter-layer film. Both methods promote the movement of atoms at the bonding interface, which produces chemical bonds (metal bonds, in the case of metal materials). In particular, the metals are bonded to each other in a solid-phase state (below the melting point of the member) by the cohesive force between metal atoms acting on the metals in close proximity to each other. Solid-phase bonding methods include normal temperature bonding, solid-phase diffusion bonding, reactive diffusion bonding, hot pressure welding, cold pressure welding, ultrasonic welding, and the like. The following will describe a case where normal temperature bonding is used as an example of the solid-phase bonding. Normal temperature bonding is solid-phase bonding performed at normal temperature (e.g., between 5° C. and 35° C.). Instead, methods other than normal temperature bonding may be used in the solid-phase bonding.
A method for bringing two members into contact and bonding the members will be described with reference to
First, the surfaces of the face 1601a and the face 1602a are treated. The following will describe the surface treatment for the face 1601a, but the same treatment may be carried out for the face 1602a as well. The surface treatment may include polishing the face 1601a. In this polishing, the face 1601a may be polished until the surface roughness of the face 1601a is not greater than Rmax=10 nm. The polishing may be performed through chemical mechanical polishing (CMP) or the like. A lower surface roughness of the face 1601a enables a lower contact pressure to be used in the bonding, and also makes it possible to increase the bonding strength. If the surface roughness of the face 1601a is low enough for normal temperature bonding before surface treatment, the face 1601a need not be polished. Furthermore, the surface treatment may include cleaning the inert layer of the face 1601a with an argon (Ar) beam or the like to activate the face 1601a. The face 1601a may be activated after polishing the face 1601a.
Then, the face 1601a and the face 1602a are brought into contact with each other, as illustrated in
In solid-phase bonding, the entire parts of the face 1601a and the face 1602a in contact with each other may be bonded. Instead, however, in the solid-phase bonding, only part of the parts of the face 1601a and the face 1602a in contact with each other may be bonded, and the other parts may not be bonded. The unbonded parts may remain in the state from before the member 1601 and the member 1602 were bonded.
A method for bonding two members using a metal inter-layer film will be described with reference to
First, the surfaces of the face 1701a and the face 1702a are treated. The following will describe the surface treatment for the face 1701a, but the same treatment may be carried out for the face 1702a as well. The surface treatment may include polishing the face 1701a. The polishing may be the same as the polishing described with reference to
Then, as illustrated in
Then, as illustrated in
A method for manufacturing the radiation detection apparatus 104 according to some embodiments will be described with reference to
The plurality of sensor units 301 are then fixed to each other to form an array by bonding each of the plurality of sensor units 301 and the substrate 305 to each other by using solid-phase bonding. As described above, the solid-phase bonding may be normal temperature bonding. The same applies to the solid-phase bonding described later with reference to
The substrate 305 is provided in common for the plurality of sensor units 301. The substrate 305 includes the conductive layer 412 that is bonded to the plurality of sensor units 301, and an insulating layer 411 that is located on the opposite side of the plurality of sensor units 301 with respect to the conductive layer 412. Instead, however, the substrate 305 may have a different configuration, and need not include the conductive layer 412, for example.
As illustrated in
To suppress stress produced in the sensor unit 301, the solid-phase bonding between the plurality of sensor units 301 and the substrate 305 may be performed at a low pressure. For example, the solid-phase bonding may be performed at a pressure where the plastic deformation amount of the semiconductor layer 402 of the sensor unit 301 is not greater than 10%.
Two adjacent sensor units 301 among the plurality of sensor units 301 may or may not be in contact with each other, and may or may not be bonded to each other. Two adjacent sensor units 301 among the plurality of sensor units 301 may be bonded to each other by solid-phase bonding, or may be bonded by a method other than solid-phase bonding.
Then, as illustrated in
A method for manufacturing the radiation detection apparatus 104 according to another embodiment will be described with reference to
Then, by bonding two sensor units 301 adjacent to each other in the array by using solid-phase bonding, the plurality of sensor units 301 are fixed to each other so as to form an array. In the method illustrated in
In the bonding between the sensor units 301, the semiconductor layers 402 of the two adjacent sensor units 301 may be bonded to each other by solid-phase bonding. Instead of or in addition thereto, the interposers 404 of the two adjacent sensor units 301 may be bonded to each other by solid-phase bonding. Instead of or in addition thereto, the mounting boards 407 of the two adjacent sensor units 301 may be bonded to each other by solid-phase bonding.
To suppress stress produced in the sensor unit 301, the solid-phase bonding between the two adjacent sensor units may be performed at a low pressure. For example, the solid-phase bonding may be performed at a pressure where the plastic deformation amount of the semiconductor layer 402 of the sensor unit 301 is not greater than 10%.
Then, as illustrated in
A method for manufacturing the radiation detection apparatus 104 according to another embodiment will be described with reference to
A method for manufacturing the radiation detection apparatus 104 according to another embodiment will be described with reference to
A method for manufacturing the radiation detection apparatus 104 according to another embodiment will be described with reference to
The plurality of semiconductor layers 402 are then fixed to each other to form an array by bonding each of the plurality of semiconductor layers 402 and the substrate 305 to each other by using solid-phase bonding. In the method illustrated in
The substrate 305 is provided in common for the plurality of semiconductor layers 402. The substrate 305 includes the conductive layer 412 that is bonded to the plurality of semiconductor layers 402, and the insulating layer 411 that is located on the opposite side of the plurality of semiconductor layers 402 with respect to the conductive layer 412. Instead, however, the substrate 305 may have a different configuration, and need not include the conductive layer 412, for example.
To suppress stress produced in the semiconductor layer 402, the solid-phase bonding between the plurality of semiconductor layers 402 and the substrate 305 may be performed at a low pressure. For example, the solid-phase bonding may be performed at a pressure where the plastic deformation amount of the semiconductor layer 402 is not greater than 10%.
Two adjacent semiconductor layers 402 among the plurality of semiconductor layers 402 may or may not be in contact with each other, and may or may not be bonded to each other. Two adjacent semiconductor layers 402 among the plurality of semiconductor layers 402 may be bonded to each other by solid-phase bonding, or may be bonded by a method other than solid-phase bonding.
Then, as illustrated in
In the process of
In the process illustrated in
The foregoing embodiments have described the radiation detection apparatus 104 in the context of the CT apparatus 100. Instead, however, the radiation detection apparatus 104 may be used in another apparatus, such as a fluoroscopic diagnostic apparatus, an object inspection apparatus, or the like, for example. Additionally, the foregoing embodiments have described the radiation detection apparatus 104 which detects radiation. However, the embodiments are not limited thereto, and the foregoing embodiments can be applied, for example, to a radiation detector that detects γ-rays, particle radiation, or the like. Additionally, the foregoing embodiments can also be applied in a diagnostic radiology apparatus, other than the CT apparatus 100, that is provided with the radiation detection apparatus 104. In this case, the diagnostic radiology apparatus includes, for example, a Positron Emission Tomography (PET) apparatus, a Single Photon Emission Computed Tomography (SPECT) apparatus, and the like.
Variations on the radiation detection apparatus 104 will be described with reference to
Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2023-128000, filed Aug. 4, 2023, Japanese Patent Application No. 2023-128003, filed Aug. 4, 2023, Japanese Patent Application No. 2024-049991 filed Mar. 26, 2024, which are hereby incorporated by reference herein in their entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-128000 | Aug 2023 | JP | national |
| 2023-128003 | Aug 2023 | JP | national |
| 2024-049991 | Mar 2024 | JP | national |
