Radiation detector

Abstract

To provide a technology that is advantageous in improving the cooling performance of a detector that detects radioactive rays and enhancing the sensitivity or the resolution of the detector.SOLUTION: A detector includes: a first member that detects a radioactive ray; a second member located around the first member; a third member having a first opening overlapping at least a part of a first region on which the first member is projected in a planar view including the first member and the second member; a fourth member having a second opening overlapping at least a part of the first region in the planar view and having higher thermal conductivity than the third member; and a penetration part provided in a third region overlapping the fourth member outside a second region on which the second member is projected in the planar view, connected to the fourth member, connected to the second member via a thermal conductive member, and having higher thermal conductivity than the third member.SELECTED DRAWING: Figure 1B

Description

Technical Field

[0001] The present invention relates to a radiation detector.

Background Art

[0002] In a detector using a CMOS image sensor or the like, in a semiconductor layer capable of directly detecting electrons, when electrons penetrate deep, crosstalk and secondary electrons may occur and the detection accuracy may decrease. In order to suppress the decrease in detection accuracy, it is effective to make the semiconductor layer thinner. Patent Document 1 discloses a detector structure in which a detection region is thinner than a peripheral region. Further, Patent Document 2 discloses a structure of a detector provided with a mechanical support layer for easily providing a thinning structure. Further, Patent Document 3 discloses a structure in which a heat conductor is connected to the back surface of a detector to improve cooling performance by ensuring the strength of the detector and increasing the surface area of the heat conductor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] CMOS and CCD sensors used as detectors consume more power and generate more heat due to their increased pixel count and high-speed operation. To cool a heated sensor, it is effective to install a cooling unit on the back of the sensor. However, in radiation detectors, radiation passes through the back of the thinned detection area, causing reflection and scattering between the sensor and the cooling unit. If cooling is insufficient because a cooling unit is not installed on the back of the detection area, the dark current and thermal noise increase due to heat generation, reducing the sensitivity and resolution of the detector.

[0005] This invention has been made in view of the above problems, and aims to provide a technology that is advantageous in improving the cooling performance of a radiation detector and increasing the sensitivity and resolution of the detector. [Means for solving the problem]

[0006] According to one aspect of the present invention, a detector is provided comprising: a first member for detecting radiation; a second member located around the first member; a third member having a first opening that overlaps with at least a portion of a first region projected onto the first member in a plan view including the first and second members; a fourth member having a second opening that overlaps with at least a portion of the first region in a plan view and has a higher thermal conductivity than the third member; and a through-hole provided in a third region that overlaps with the fourth member outside the second region projected onto the second member in a plan view, connected to the fourth member, connected to the second member by a thermal conductive member, and having a higher thermal conductivity than the third member. [Effects of the Invention]

[0007] According to the present invention, it is possible to improve the cooling performance of a radiation detector and provide a technology that is advantageous in increasing the sensitivity and resolution of the detector. [Brief explanation of the drawing]

[0008] [Figure 1A] This is a plan view configuration diagram of the detector according to the first embodiment. [Figure 1B]This is a cross-sectional view of the detector according to the first embodiment. [Figure 1C] This is a plan view configuration diagram of the detector according to the first embodiment. [Figure 2A] This is a cross-sectional view of the detector according to the first embodiment. [Figure 2B] This is a cross-sectional view of the detector according to the second embodiment. [Figure 2C] This is a cross-sectional view of the detector according to the third embodiment. [Figure 2D] This is a cross-sectional view of the detector according to the fourth embodiment. [Figure 3A] This is a cross-sectional view of the detector according to the fifth embodiment. [Figure 3B] This is a cross-sectional view of a detector according to a modified example of the fifth embodiment. [Figure 3C] This is a cross-sectional view of a detector according to a modified example of the fifth embodiment. [Figure 3D] This is a cross-sectional view of the detector according to the sixth embodiment. [Figure 4A] This is a plan view configuration diagram of the detector according to the seventh embodiment. [Figure 4B] This is a plan view configuration diagram of the detector according to the seventh embodiment. [Figure 5] This is a cross-sectional view of the detector according to the eighth embodiment. [Figure 6] This is a schematic diagram of the radiation imaging device according to the ninth embodiment. [Figure 7] This is a schematic diagram of the photoelectric conversion device according to the 10th embodiment. [Modes for carrying out the invention]

[0009] Hereinafter, embodiments for implementing the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. In the following description and drawings, common components across multiple drawings are denoted with common reference numerals. Therefore, the common components will be described by referring to multiple drawings in relation to each other, and the description of the components with common reference numerals will be omitted as appropriate. Or, although multiple embodiments will be described, the description will be omitted for points where one embodiment may be the same as another embodiment.

[0010] <First Embodiment> The first embodiment according to the present invention will be described below using FIGS. 1A to 2A. FIGS. 1A, 1B, and 1C show a configuration diagram of the detector 1 according to the present embodiment. FIG. 1A shows a top view when viewed from the upper surface side of the detector 1 in a plan view. FIG. 1B shows a cross-sectional view of the detector 1 along the line A - A' of FIG. 1A. FIG. 1C shows a bottom view when the detector 1 is viewed from the lower surface side in a plan view. FIG. 2A shows an enlarged cross-sectional view of the right-side portion of the detector 1 in FIG. 1B.

[0011] As shown in FIGS. 1A, 1B, and 1C, the detector 1 includes a first member 13, a second member 14, a third member 21, a fourth member 22, a heat conduction member 30, and a through-hole 31. The detector 1 is an image sensor incorporating a semiconductor layer 15 including a first member 13 for detecting radiation and a second member 14 for processing the detected signal.

[0012] The first member 13 and the second member 14 are composed of a semiconductor layer 15. The semiconductor layer 15 is preferably a single-crystal layer of silicon, germanium, or the like, but may also be a polycrystalline layer. Furthermore, it is desirable that the first member 13 and the second member 14 have an integrated structure manufactured from a semiconductor substrate. The planar shapes of the first member 13 and the second member 14 and their positional relationship are not particularly limited, but for example, the second member 14 is located around the first member 13 and is provided to have a rectangular annular planar shape around the first member 13, which has a rectangular planar shape. In a planar view including both the first member 13 and the second member 14, the region onto which the first member 13 is projected is defined as the first region 10, and the region onto which the second member 14 is projected is defined as the second region 11. The plane including both the first member 13 and the second member 14 may include, for example, the top surface of the first member 13 and the top surface of the second member 14. Furthermore, the plane containing both the first member 13 and the second member 14 may be, for example, a virtual plane that penetrates both the first member 13 and the second member 14.

[0013] The first component 13 is part of a detector that converts electrons generated by incident radiation into an output signal. The first component 13 includes a plurality of pixels and readout circuits for forming an image based on radiation, and has a structure in which these plurality of pixels and readout circuits are arranged. The first component 13 may contain silicon, germanium, or cadmium.

[0014] The second component 14 is a peripheral circuit and includes a drive circuit, control circuit, input / output terminal section, signal processing circuit, output circuit, etc. The input / output terminal section includes an input terminal section and an output terminal section. The drive circuit drives the readout circuit of the first component 13 by scanning it. The control circuit controls the drive timing of the drive circuit, signal processing circuit, etc., and includes a timing generator, etc. Power and control signals are input from the outside to the input terminal section. Signals are output to the outside from the output terminal section. The signal processing circuit processes the signals from the readout circuit located on the first component 13 and includes an amplification circuit and an AD conversion circuit. The output circuit converts the signals obtained by the signal processing circuit into a predetermined format and outputs it, and includes a differential transmission circuit.

[0015] Detector 1 is a typical image sensor such as CMOS (Complementary Metal Oxide Semiconductor) or CCD (Charge Coupled Device). CMOS and CCD use a method in which electrons accumulated in a photodiode are transferred to a floating diffusion layer via a transfer transistor, and the potential is read out via a source follower. CMOS and CCD may also use a readout method in which the potential of the accumulation section is directly set as the gate potential of the source follower without using a transfer transistor. Furthermore, detector 1 may use the photon counting principle, and devices such as SPAD (Single Photon Avaranche Diode) may be used as detector 1.

[0016] As shown in Figure 1B, the support portion 20 is provided on the third member 21 so as to support the semiconductor layer 15, which includes the first member 13 and the second member 14, in the second region 11. In this embodiment, the side of the first member 13 and the second member 14 that contacts the support portion 20 is defined as the back side, and the opposite side is defined as the front side. The support portion 20 is provided with an opening 201 through which all or part of the back surface of the first member 13 is exposed. The radiation to be detected by the detector 1 is irradiated onto the first member 13 from the front side and passes through the first member 13 to the back side. To prevent the radiation from colliding and scattering, it is desirable to create a vacuum in the first region 10 on both the front and back sides of the first member 13. Operating the detector 1 in a vacuum is a means of creating a vacuum in the first region 10 on both the front and back sides of the first member 13. Alternatively, the entire detector 1 may be operated in a vacuum, or only a part of the structure of the detector 1, including the first region 10, may be operated in a vacuum. For example, the space formed by at least the opening of the support portion 20 can be a vacuum. Also, the vacuum portion of the first region 10 can be the space formed by at least the opening of the support portion 20.

[0017] As an example of radiation, let's describe the case where an electron beam is irradiated onto the detector 1. When the electron beam enters the first member 13, secondary electrons are generated within the first member 13, and the resolution may decrease due to crosstalk between pixels. If the thickness of the first member 13 is greater than the desired value, the secondary electrons spread over a wider area, and the decrease in resolution becomes more pronounced. On the other hand, if the first member 13 is thinner than the desired value, the generation of secondary electrons decreases, leading to a decrease in signal. As a result, the S / N ratio of the detector 1 decreases. Therefore, there is a preferred range for the thickness of the first member 13. The thickness of the first member 13 that suppresses crosstalk while maintaining sufficient sensitivity is preferably 10 μm or more and 100 μm or less. Typically, the thickness of the first member 13 is preferably 25 μm or more and 75 μm or less. Note that the first member 13 can be configured such that at least a portion of its thickness falls within these preferred ranges. When the first member 13 and the second member 14 are formed from a single material such as a semiconductor substrate, the two can be simultaneously thinned to the aforementioned thickness, or only the first member 13 can be thinned by etching. In this embodiment, the thickness of the first member 13 is shown to be smaller than the thickness of the second member 14. However, even if the thicknesses of the first member 13 and the second member 14 are the same, the same cooling effect as in this embodiment can be obtained.

[0018] The above description explained the detection of electron beams as an example of radiation detected by detector 1, but the effects of the present invention are also effective for other types of radiation. The radiation detected by detector 1 may be ionizing radiation such as X-rays or gamma rays, or particle beams such as alpha rays, beta rays, neutron beams, proton beams, heavy ion beams, or meson beams. This embodiment is suitable for detecting electron beams, but when detecting radiation other than electron beams, the structure of detector 1, particularly the thickness of the first member 13, should be adjusted according to the transmission and absorption characteristics of the radiation.

[0019] The support portion 20 reinforces the mechanical strength of the first member 13 and the second member 14 by bonding them to the back surface of the second member 14 in the second region 11 via an adhesive or the like. The material of the support portion 20 may be a semiconductor, an insulator, or a conductor, but it is preferable that its coefficient of thermal expansion is close to that of the first member 13 and the second member 14 in order to reduce stress between them. That is, for example, if the first member 13 and the second member 14 are silicon, it is preferable that the support portion 20 be silicon, and if the first member 13 and the second member 14 are germanium, it is preferable that the support portion 20 be germanium. The support portion 20 may also be a semiconductor single crystal with a continuous crystal structure with that of the second member 14.

[0020] The third member 21 is a circuit board, such as a printed circuit board (PCB) or a ceramic substrate. A support portion 20 is provided on one side of the third member 21. The third member 21 is provided with an opening 211 through which all or part of the back surface of the first member 13 is exposed. The third member 21 is electrically connected to the second member 14, which is supported by the support portion 20. Electrical components (not shown) are also arranged on the third member 21. The third member 21 has a larger area than the second member 14 in plan view in order to accommodate a large number of electrical components, but some components may be mounted on a separate substrate (not shown).

[0021] The fourth member 22 is provided on the side of the third member 21 opposite to the side on which the support portion 20 is provided. An opening 221 is provided that exposes all or part of the back surface of the first member 13. The fourth member 22 is made of a material with high thermal conductivity and is connected to a cooler (not shown) on its back side. In particular, the fourth member 22 has higher thermal conductivity than the third member 21. The heat generated in the first member 13 and the second member 14 is dissipated to the cooler via the support portion 20, the third member 21, and the fourth member 22.

[0022] When radiation passes through the first member 13, it is desirable that the opening 201 of the support part 20, the opening 211 of the third member 21, and the opening 221 of the fourth member 22 each overlap with at least a portion of the first region 10 in order to suppress scattering and reflection of the transmitted radiation. If the openings 201, 211, and 221 of the support part 20, the third member 21, and the fourth member 22 are narrower than the first region 10, scattering and reflection of radiation will cause unwanted signals to become noise, degrading imaging performance. The sides of the openings 201, 211, and 221 may coincide. Also, the space formed by the openings 201, 211, and 221 may be a vacuum.

[0023] On the other hand, the support portion 20, the third member 21, and the fourth member 22 are heat dissipation paths that dissipate the heat generated by the first member 13 and the second member 14.

[0024] If, for example, the parts that overlap with the first region 10 in each section are designated as openings 201, 211, and 221, then the parts that overlap with the frame-shaped area of ​​the second region 11 become heat dissipation paths. However, in this case, the contact area between the members becomes smaller compared to the case where there are no openings 201, 211, and 221, and therefore the thermal resistance increases.

[0025] Therefore, the sizes of the apertures 201, 211, and 221 should be narrow enough to avoid scattering or reflecting radiation. Specifically, in Figure 1B, it is desirable that the edges of the apertures 201, 211, and 221 of the support portion 20, the third member 21, and the fourth member 22 be located on the boundary line between the first region 10 and the second region 11. The above describes the basic structure of the detector 1.

[0026] The first component 13 and the second component 14 are expected to consume approximately 0.1W to several tens of watts during operation, and there is a problem that the dark current of the pixel portion increases due to the temperature rise caused by heat generation. Power consumption will increase further if the first component 13 is made more pixelated to achieve higher resolution, if the number of signal lines is increased to achieve higher speed, or if the signal processing of the second component 14 is accelerated.

[0027] Common thermal management methods for semiconductor devices include air cooling of the semiconductor device surface and installing a material with high thermal conductivity or a heat sink on the back surface of the temperature-rising part to dissipate heat. On the other hand, since the detector 1 preferably operates in a vacuum, air cooling is difficult, and cooling from the back surface is also insufficient due to the aforementioned openings 201, 211, and 221. Furthermore, the thinning of the first member 13 increases the thermal resistance in the horizontal direction, making cooling difficult, which is a challenge.

[0028] The following describes the details of the components interposed between the heat source and the cooler in the detector 1 according to this embodiment. Connections between the second component 14 and the support 20, between the support 20 and the third component 21, between the third component 21 and the fourth component 22, and between the fourth component 22 and a cooler (not shown) require connecting materials. These connecting materials include adhesives, grease, gels, solder, and die-bonding materials. Therefore, it is unavoidable that multiple components are interposed at each connection. Furthermore, materials such as adhesives, greases, and gels are difficult to control in thickness, and their thermal resistance changes in proportion to their thickness.

[0029] Furthermore, the third component 21, which is a circuit board, is increasingly multilayered with wiring and insulating layers, which imposes constraints on the substrate material during manufacturing. PCBs, which are commonly used as circuit boards, can be multilayered, but they have low thermal conductivity. For example, the thermal conductivity of FR4 (Flame Retardant type 4) substrate is 0.2 W / (m·K) to 0.4 W / (m·K). On the other hand, circuit boards with high thermal conductivity, such as alumina substrates (Al2O3, 14 W / (m·K)) and AlN substrates (150 W / (m·K)), have been developed. However, circuit boards with high thermal conductivity have other challenges, such as increased costs due to materials and multilayering, and the occurrence of substrate warping during the ceramic manufacturing process, so it is not always possible to select a circuit board with high thermal conductivity. Using the present invention also contributes to providing a detector at low cost.

[0030] To address the above challenges, it is effective to use materials with high thermal conductivity for all components interposed from the heat source to the cooler. Furthermore, reducing the number of interposed components and increasing the surface area of ​​the heat dissipation path are also effective in lowering thermal resistance.

[0031] Therefore, in this embodiment, the third member 21 has a third region 12 that overlaps with the fourth member 22 outside the second region 11 in the plan view, and the third member 21 has a structure in which a through portion 31 is arranged in the third region 12. Here, the through portion 31 is a member made of a material having a higher thermal conductivity than the third member 21, and may be a thermal conductor or conductive material. The through portion 31 is connected to the fourth member 22 and, on the opposite side, is connected to the second member 14 via a thermal conductive member 30. The thermal conductive member 30 is connected to the surface side of the second member 14. The third region 12 is the region from the solid line indicating the outer circumference of the second region 11 to the dashed line indicating the outer circumference of the fourth member 22 in Figure 1A.

[0032] The through-section 31 may include, at least in part, a material with high thermal conductivity such as gold (Au), tungsten (W), copper (Cu), titanium (Ti), tantalum (Ta), aluminum (Al), ruthenium (Ru), or carbon graphite. Similarly, the fourth member 22 may also use a material with high thermal conductivity, but because its shape is larger than that of the through-section 31, a relatively low-cost copper (Cu) alloy may be used. It should be noted that while materials with high thermal conductivity are desirable for the heat-conducting member 30, the through-section 31, and the fourth member 22, they do not need to be made of the same material.

[0033] According to this embodiment, a heat dissipation path can be added to the heat dissipation path that transmits heat generated by the first member 13 and the second member 14 to the fourth member 22 via the support portion 20 and the third member 21, which transmits heat to the fourth member 22 via the heat conduction member 30 and the penetration portion 31. Therefore, according to this embodiment, the overall thermal resistance of the detector 1 can be reduced. Furthermore, since the heat conduction member 30 is connected to the surface side of the second member 14, the second member 14 can be cooled from both the back side connected to the support portion 20 and the front side connected to the heat conduction member 30.

[0034] In Figure 1B, consider the thermal resistance from the second member 14 to the surface of the fourth member 22 via the third member 21. A typical thermal resistance r (K / W) is given by the following equation. r = d / (A·λ) Here, d is the thickness (m) and A is the area (m²). 2 ), where λ is the thermal conductivity (W / (m·K)).

[0035] The third member 21 has a thickness of 0.003 m and a cross-sectional area of ​​0.001 m² perpendicular to the thickness direction in which it overlaps with the second member 14, excluding the opening 211. 2 Assuming a PCB substrate with a thermal conductivity of 0.2 W / (m·K), the thermal resistance r1 of the third component 21 is calculated as follows: r1=0.003(m) / 0.2W / (m·K) / 0.001(m 2 ) ≈15.0 (K / W) In addition, thermal resistance from the adhesive layer used to connect the third member 21 is added.

[0036] On the other hand, consider the thermal resistance of the heat conductive member 30 and the through-hole 31. Although the area of ​​the heat conductive member 30 and the through-hole 31 is small compared to the area of ​​the third member, they have high thermal conductivity and do not require adhesive or anything similar between them. For this reason, with respect to the heat conductive member 30 and the through-hole 31, it is preferable to install them in multiple locations to obtain a heat dissipation effect.

[0037] For example, let's assume that the heat conductive member 30 is a circular Au bonding wire with a length of 1 mm and a cross-section diameter of 100 μm, and the through-hole 31 is a circular Cu via with a thickness of 3 mm and a cross-section diameter of 300 μm. Let the thermal conductivity of Au and Cu be 315 W / (m·K) and 400 W / (m·K), respectively. The thermal resistance r when there are 100 heat conductive members 30 and through-holes 31 is calculated as follows. r=0.001(m) / 315W / (m K) / (0.00005(m)×0.00005(m)×π×100(pieces))+0.003(m) / 400W / (m・K) / (0.00015(m)×0.00015(m)×π×100(pieces)) ≈5.10 (K / W)

[0038] Therefore, when considering the thermal resistance from the second member 14 to the surface of the fourth member 22, in this embodiment, the thermal resistance of the heat dissipation path of the heat conduction member 30 and the penetration portion 31 is added in parallel to the thermal resistance of the heat dissipation path of the heat conduction path of the heat conduction member 30 and the penetration portion 31, which is 15.0 (K / W). As a result, in this embodiment, the thermal resistance from the second member 14 to the surface of the fourth member 22 is approximately 3.8 (K / W), which is the combined thermal resistance of both, and the thermal resistance can be reduced to less than 1 / 3 compared to the case without the heat conduction member 30 and the penetration portion 31.

[0039] Furthermore, a substrate with high thermal conductivity can be used as the third member 21. In this case, the thermal resistance can be further reduced. Also, as shown in Figure 2A, the thermal conductive member 30 may be connected to the second member 14 via an electrode 33a provided on the surface side of the second member 14. The electrode 33a is connected to the wiring layer 32a formed inside the second member 14, and the second member 14 can be cooled with low thermal resistance, resulting in a large cooling effect. As a result, the temperature rise of the first member 13 and the second member 14 can be suppressed.

[0040] Figure 2A shows an enlarged cross-sectional view of the detector 1 according to this embodiment. Here, the first member 13 and the second member 14 are shown with the same thickness, but the first member 13 may be thinner than the second member 14. Furthermore, it is desirable that the support portion 20 be located in the second region 11. For example, if the support portion 20 is located in the first region 10, the mechanical strength of the first member 13 can be increased, but radiation incident on the first region 10 will be reflected at the boundary between the first member 13 and the support portion 20. On the other hand, if the support portion 20 is placed further outside the boundary between the first region 10 and the second region 11, the contact area between the second member 14 and the support portion 20 decreases, and the effect of dissipating heat generated by the second member 14 decreases. Therefore, it is desirable that the edge of the opening 201 of the support portion 20 be located at the boundary between the first region 10 and the second region 11. Similarly, it is desirable that the edges of the opening 211 of the third member 21 and the opening 221 of the fourth member 22 be located at the boundary between the first region 10 and the second region 11.

[0041] The heat conduction member 30 can be connected to an electrode 33a that has been brought out to the surface of the wiring layer 32a of the semiconductor layer of the second member 14 in the second region 11. The electrode 33a is a ground electrode and is fixed to a ground voltage, which is a constant potential. The heat conduction member 30 is connected to the electrode 33a and is fixed to a constant potential. If the outermost surface of the second member 14 is a passivation layer (not shown), an opening can be provided in the passivation layer to connect the electrode 33a and the heat conduction member 30. The heat conduction member 30 is a conductor, and at least a portion of the wiring layer 32a of the second member 14 is at a fixed potential for supplying the ground voltage, and the fourth member 22 is also at the same potential as the ground voltage. In this way, by having the heat conduction member 30 also serve as wiring that supplies the ground voltage, the voltage is stabilized, and as a result, noise can be suppressed and reduced. Furthermore, in order to efficiently dissipate the heat generated by the second member 14, it is desirable that the heat conduction member 30 be connected to a wiring layer that leads to the interior of the second member 14.

[0042] In Figure 2A, the heat conductive member 30 is connected to the wiring layer 32a via the electrode 33a. However, if the second member 14 is configured with an antistatic layer or an electron beam shielding layer, the heat dissipation effect can be obtained even if the heat conductive member 30 is connected to them instead of the wiring layer 32a.

[0043] Furthermore, the heat conductive member 30 may also be a heat conductive wiring or bonding wire. In this embodiment, gold (Au), which has high thermal conductivity and is resistant to oxidation, is used as an example, but it is not limited to this; the heat conductive member 30 may be gold (Au), silver (Ag), copper (Cu), aluminum (Al), or an alloy thereof. By having the bonding wire for electrical connection also serve as a heat dissipation path, thermal noise can be suppressed while making more efficient use of space than connecting a separate heat conductive wiring for heat dissipation.

[0044] The fourth component 22 is connected to a cooler (not shown). The cooler to which the fourth component 22 is connected can be, for example, a Peltier element. A Peltier element requires a separate cooling mechanism for heat transfer, but a water-cooled structure is effective when operating in a vacuum. A connection structure (not shown) may be provided between the fourth component 22 and the cooler for connection to a cooler including a water-cooled structure.

[0045] As described above, according to this embodiment, it is possible to cool the first member 13 and the second member 14 with low thermal resistance, reducing the capacity required to cool the cooling section, thereby simplifying the device and reducing costs. Furthermore, according to this embodiment, the dark current of the pixel portion of the first member 13 can be reduced, making it possible to provide a detector 1 with a good signal-to-noise ratio. Thus, according to this embodiment, the cooling performance of the radiation-detecting detector 1 can be improved, and the sensitivity and resolution of the detector 1 can be increased.

[0046] <Second Embodiment> A second embodiment of the present invention will be described below with reference to Figure 2B. In this embodiment, a connection structure between the second member 14 and the fourth member 22 that differs from that of the first embodiment will be described.

[0047] Figure 2B shows an enlarged cross-sectional view of the detector according to this embodiment. The structure shown in Figure 2B is different from the structure shown in Figure 2A in that the support portion 20 is eliminated and the second member 14 is connected to the fourth member 22 via adhesive or the like without going through the third member 21. The structure in which the second member 14 is connected to the fourth member 22 without going through the support portion 20 or the third member 21, as in this embodiment, can reduce the number of intervening members and thus reduce thermal resistance.

[0048] <Third Embodiment> In the second embodiment, the first member 13 and the second member 14, which are semiconductor layers such as silicon, are thinned, and the second member 14 is connected to a fourth member 22, which has significantly different physical properties such as stress, strain, and thermal expansion coefficient. Therefore, in the second embodiment, there is a risk of applying mechanical load to the thinned first member 13 and the second member 14, increasing the possibility of failure. Accordingly, a third embodiment of the present invention will be described below with reference to Figure 2C.

[0049] Figure 2C shows an enlarged cross-sectional view of the detector according to this embodiment. The structure shown in Figure 2C is one in which the fourth member 22 is divided into multiple parts and the fourth member 22 is connected to the third member 21 from above and below. In the structure shown in Figure 2C, the fourth member 22 is divided into three parts, fourth member 22a, fourth member 22b, and fourth member 22c, in order from the side closer to the second member 14 to the side further away. A support part 20 may be interposed between the second member 14 and the fourth member 22a, as in the first embodiment, or it may not be interposed, as in the second embodiment. The fourth member 22a is connected to the third member 21 and the fourth member 22b on its back side. The third member 21 and the fourth member 22b are connected to the fourth member 22c on their back sides. The connections between these members are made via adhesive, grease, or the like.

[0050] In this embodiment, since the fourth member 22 is divided as described above, the support portion 20 or the second member 14 and the fourth member 22a can be connected first when connecting the members. This increases the strength of the first member 13 and the second member 14, and then allows the first member 13 and the second member 14 to be connected to the other fourth member 22b, the fourth member 22c, and the third member 21. With this embodiment, which allows the members to be connected in this way, the mechanical load on the first member 13 and the second member 14 due to pressing during connection can be reduced.

[0051] <Fourth Embodiment> In the third embodiment, dividing the fourth member 22 into multiple parts necessitates the use of adhesive, grease, etc., between them, which may increase the thermal resistance. Therefore, the fourth embodiment according to the present invention will be described below with reference to Figure 2D.

[0052] Figure 2D shows an enlarged cross-sectional view of the detector according to this embodiment. The structure shown in Figure 2D is one in which the thickness of the support portion 20 or the fourth member 22 is adjusted so that the surface height of the second member 14 and the surface height of the through portion 31 are the same. One end and the other end of the heat conductive member 30 are connected to the surface of the second member 14 and the surface of the through portion 31, which are the same height.

[0053] In the structure shown in Figure 2D, since the surface height of the second member 14 and the surface height of the through-hole 31 are the same, the length of the heat conduction member 30 can be shortened, and the thermal resistance of the heat conduction member 30, which is proportional to its length, can be reduced. Therefore, the structure shown in Figure 2D is advantageous for cooling the second member 14.

[0054] <Fifth Embodiment> A fifth embodiment of the present invention will be described below with reference to Figures 3A to 3C. In this embodiment, the cross-sectional structure of the through-port 31, which can be adopted in any of the other embodiments, will be described.

[0055] Figure 3A shows an enlarged cross-sectional view of the through-hole 31 according to this embodiment. As shown in Figure 3A, an electrode 33b is provided on the surface side of the through-hole 31. The through-hole 31 is connected to the heat conductive member 30 via the electrode 33b on the surface side. Connecting the through-hole 31 to the heat conductive member 30 via the electrode 33b in this way improves ease of connection. On the back side, the through-hole 31 is connected to a fourth member 22 which is connected to a cooler (not shown).

[0056] The third member 21 is a circuit board that connects to numerous wirings of the second member 14, and has a multilayer laminated structure having multiple insulating layers and wiring layers. In other embodiments, the third member 21 is shown in Figure 3A as an example of the laminated structure of the third member 21, and includes a multilayer structure including multiple laminated layers 21a to 21e. In other embodiments, the third member 21 may have a multilayer structure similar to that of this embodiment. When the third member 21 has a multilayer laminated structure, and when the number of layers is further increased, and when the thickness of the detector including the third member 21 increases, the effect of cooling the second member 14 via the heat conductive member 30 and the through-hole 31 becomes even greater.

[0057] The through-hole 31 can utilize multiple grounding voltage wires that are electrically insulated from the laminated structure of the three members 21 and fixed at a constant potential. By using multiple grounding voltage wires set to reduce electrical impedance, it becomes possible to share multiple heat dissipation paths.

[0058] This embodiment is subject to various modifications. Figures 3B and 3C show enlarged cross-sectional views of the through-port 31 according to a modified example of this embodiment.

[0059] As a modified example of this embodiment, as shown in Figure 3B, an electrode 33c extended in the same plane may be used to connect the heat conductive member 30 and the penetration portion 31. In this case, the mechanical strength of the heat conductive member 30, such as wire bonding, can be maintained.

[0060] Furthermore, as another modification of this embodiment, as shown in Figure 3C, each part of the through-section 31, which is divided into, for example, multiple parts 31a to 31d within the third member 21, may be connected within the third member 21 via multiple wirings 32b. In this case, the multiple parts 31a to 31d of the through-section 31 are arranged to be offset in the multi-layered in-plane direction of the third member 21. Each wiring 32b is a metal wiring and is provided to connect two adjacent parts of the through-section 31. In this modification as well, it is possible to use the heat conduction by free electrons in the metal wiring 32b as a heat dissipation path.

[0061] The cross-sectional structure of the through-hole 31 has been described above using Figures 3A to 3C. However, for example, multiple heat-conducting members 30 of the same potential may be connected to the same through-hole 31, or the through-holes 31 may be connected within the third member 21. Furthermore, a greater cooling effect can be obtained by installing multiple through-holes 31 in the third region 12 of the third member 21.

[0062] <Sixth Embodiment> In any embodiment of the present invention, it is sufficient that at least some of the heat conductive members 30 are connected to the through-holes 31, and it is not necessary for all of the heat conductive members 30 to be connected to the through-holes 31. For example, if the heat conductive members 30 also serve as heat conductive wiring or bonding wires, some of the heat conductive members 30 do not need to be connected to the through-holes 31. In this case, as shown in Figure 3D, some of the heat conductive members 30 may be connected to wiring 32c provided in the third member 21 via vias 34, etc., and connected to electrical components of the third member 21 (not shown) via wiring 32c. Although it is difficult to obtain a cooling effect with the structure shown in Figure 3D alone, a cooling effect can be obtained for the detector 1 as a whole by arbitrarily mixing this structure with the through-holes 31 shown in at least one of Figures 3A to 3C.

[0063] <Seventh Embodiment> A seventh embodiment of the present invention will be described below with reference to Figures 4A and 4B. In this embodiment, the arrangement of the through-port 31, which can be adopted in any of the other embodiments, will be described.

[0064] Figures 4A and 4B are explanatory diagrams of this embodiment, and are top views showing the positional relationship between the first region 10, the second region 11, and the third region 12, as well as the arrangement of the through-hole 31 in the third region 12. In both Figure 4A and Figure 4B, a fourth member 22 is formed on the back surface of the third member 21, and the outer circumference of the fourth member 22 is shown by a dashed line. Note that the heat conductive member 30 is omitted in Figures 4A and 4B.

[0065] The third region 12, where the third member 21 and the fourth member 22 overlap outside the second region 11, is the region from the solid line indicating the outer circumference of the second region 11 to the dashed line indicating the outer circumference of the fourth member 22 in Figures 4A and 4B. A penetration portion 31 is placed in this third region 12 and connected to the second member 14 by a heat conductive member 30.

[0066] Furthermore, due to the configuration of the image sensor, each of the regions up to the first region 10, the second region 11, and the third region 12 generally has a roughly rectangular outer perimeter when viewed from above. It is desirable to install the through portion 31 within the third region 12, close to the second region 11, in order to shorten the heat conductive member 30.

[0067] Furthermore, the second region 11 has a structure with other components on its back surface, while the first region 10 has a vacuum with an open structure on its back surface. Therefore, a higher heat dissipation effect can be obtained by installing the through-hole 31 in a position close to the first region 10, which contributes less to heat dissipation to the back surface.

[0068] As shown in Figure 4A, in order to obtain a cooling effect, it is effective to place the through-holes 31 near the outer perimeter of two sides of the third region 12, which has a rectangular outer perimeter in a plan view, that are closer to the outer perimeter of the first region 10, which is also a rectangle in a plan view. Of course, the through-holes 31 may also be placed near the outer perimeter of all four sides of the third region 12.

[0069] Figure 4A shows a case where the through-holes 31 are arranged at equal intervals, but the through-holes 31 do not necessarily need to be arranged at equal intervals. Figure 4B shows an example in which the through-holes 31 are concentrated closer to the first region 10. Furthermore, in order to prevent the generation of an uneven temperature distribution in the first region 10, it is desirable that the arrangement of the through-holes 31 be linearly symmetrical with respect to the first region 10. Note that the number of through-holes 31 in Figures 4A and 4B is just an example for illustrative purposes, and the number of through-holes 31 can be determined based on the circuit design of the third member 21, etc.

[0070] <Eighth Embodiment> An eighth embodiment of the present invention will be described below with reference to Figure 5. In this embodiment, a replaceable structure for the detector 1 that can be adopted in any of the other embodiments will be described.

[0071] Figure 5 shows a cross-sectional view of the detector 1 according to this embodiment. The detector 1 can be configured to allow replacement of the detector 1 or a part of the detector 1 in the event of deterioration, electrical charging, or other malfunctions occurring inside the detector 1 due to radiation irradiation.

[0072] The structure shown in Figure 5 is one in which a fixing part 24a is provided on the fourth member 22 and a fixing part 24b is provided on the cooler 23. The fixing parts 24a and 24b have a structure that allows them to be connected and fixed to each other. By fixing the corresponding fixing parts 24a and 24b to each other, the cooler 23 is fixed to the fourth member 22, with all or part of its surface in contact with all or part of its back surface. Multiple sets of fixing parts 24a and 24b may be provided to more securely fix the cooler 23 to the fourth member 22. In this way, the fourth member 22 is detachably connected to the cooler 23, which is another member, on the opposite side from the third member 21 with respect to the fourth member 22.

[0073] To prevent a gap from forming between the fourth member 22 and the cooler 23, the gap can be filled using a reconnectable material such as grease or gel. This minimizes the increase in thermal resistance due to the gap. In the structure shown in Figure 5, the fourth member 22 can be separated from the cooler 23, allowing the detector 1 to be removed from the cooler 23. This improves the maintainability of the device using the detector 1 and reduces costs through partial replacement.

[0074] Although Figure 5 shows an example based on the structure of Figure 2D, the invention is not limited to this, and a detector having the structure of Figures 2A to 2C can be configured in the same way as in this embodiment. For example, in the structure of Figure 2A, fixing parts 24a and 24b can be installed on the third member 21 and the fourth member 22, respectively, so that the fourth member 22 can be fixed to the third member 21. In this case, the third member 21 is connected to the fourth member 22 in a detachable manner. In this case, the fourth member 22 can be excluded from the group of replaceable parts, thus further reducing replacement costs. A cooling effect can be obtained by configuring the detector 1 within the scope of the replaceable structure.

[0075] <Ninth Embodiment> A ninth embodiment of the present invention will be described below with reference to Figure 6. In this embodiment, a radiation imaging device using any of the detectors 1 according to the first to eighth embodiments will be described.

[0076] Figure 6 shows the configuration of the radiation imaging device 101 according to this embodiment. The radiation imaging device 101, which is one embodiment of a radiation detection device, may include a detector 100 including a pixel array 110 having a plurality of pixels, and a signal processing unit 122 that processes signals from the detector 100. Any of the detectors 1 according to the first to eighth embodiments can be applied as the detector 100. The detector 100 may have, for example, a panel shape. The signal processing unit 122 may be configured as part of the control device 120, as illustrated in Figure 6, or it may be housed in the same housing as the detector 100, or it may be housed in a different housing from the detector 100 and the control device 120. The radiation imaging device 101 is a device for obtaining radiation images by the energy subtraction method. The energy subtraction method is a method for obtaining new radiation images (e.g., bone images and soft tissue images) by processing multiple images obtained by imaging a subject multiple times with different energy levels of radiation. The term "radiation" can include, for example, X-rays, as well as alpha rays, beta rays, gamma rays, particle beams, and cosmic rays.

[0077] The radiation imaging device 101 may include a radiation source 140 that generates radiation, an exposure control device 130 that controls the radiation source 140, and a control device 120 that controls the exposure control device 130 (radiation source 140) and the detector 100. The control device 120, which is the control unit, may include a signal processing unit 122 that processes signals supplied from the detector 100, as described above. All or part of the functions of the control device 120 may be incorporated into the detector 100. Alternatively, some of the functions of the detector 100 may be incorporated into the control device 120. The control device 120 may consist of a computer (processor) and a memory that stores a program to be provided to the computer. The signal processing unit 122 may consist of a part of the program. Alternatively, the signal processing unit 122 may consist of a computer (processor) and a memory that stores a program to be provided to the computer. All or part of the control device 120 may consist of a digital signal processor (DSP) or a programmable logic array (PLA). The control device 120 and the signal processing unit 122 may be designed and manufactured by a logic synthesis tool based on a file describing their operation.

[0078] The exposure control device 130 may, for example, have an exposure switch and, when the exposure switch is turned on, cause the radiation source 140 to emit radiation, and may also notify the control device 120 of information indicating the timing of the radiation emission. Alternatively, the exposure control device 130 may cause the radiation source 140 to emit radiation in response to a command from the control device 120.

[0079] Radiation source 140 can emit radiation whose energy (wavelength) changes during the continuous emission period. Using such radiation, radiation images can be acquired at two different energies, and a new radiation image can be obtained by processing these radiation images using the energy subtraction method.

[0080] Alternatively, the radiation source 140 may have a function to change the energy (wavelength) of the radiation. For example, the radiation source 140 may have a function to change the energy of the radiation by changing the tube voltage (the voltage applied between the cathode and anode of the radiation source 140).

[0081] Each of the multiple pixels constituting the pixel array 110 of the detector 100 may have a conversion element that converts radiation into an electrical signal (e.g., electric charge), a processing circuit that processes the electrical signal output from the conversion element, and a holding unit that samples and holds the electrical signal output from the processing circuit. Each conversion element may be configured to directly convert radiation into an electrical signal, or it may be configured to convert radiation into light such as visible light and then convert the light into an electrical signal. In the latter case, a scintillator may be used to convert radiation into light. The scintillator may be shared by multiple pixels of the pixel array 110.

[0082] <Tenth Embodiment> A tenth embodiment of the present invention will be described below with reference to Figure 7. In this embodiment, as an example of application of the detector 1 according to the first to eighth embodiments as a photoelectric conversion device, a detection system comprising a photoelectric conversion device using the detector 1 and a processing device that processes the signal output from the photoelectric conversion device will be described.

[0083] The detection system comprises at least a photoelectric converter and a signal processing circuit that processes the signal output from the photoelectric converter. The signal processing portion of the configuration shown in Figure 7, described below, may be located in the cloud. Here, we will illustrate with an example of a device in which a photoelectric converter using detector 1 is incorporated as an imaging device. Examples of devices in which a photoelectric converter is incorporated as an imaging device include electronic devices such as cameras and smartphones. Here, the concept of a camera includes not only devices whose primary purpose is photography, but also devices that have photography functions as an auxiliary function (for example, personal computers and portable terminals such as tablets).

[0084] Figure 7 is a schematic diagram of an EQP (Equipment Equipped with Photoelectric Converter 200). Examples of EQPs include electronic devices (information equipment) such as cameras and smartphones, as well as office equipment such as photocopiers and scanners. Other examples of EQPs include transportation equipment such as automobiles, airplanes, ships, and railway vehicles; medical equipment such as endoscopes and radiography equipment; analytical instruments such as scanning electron microscopes and transmission electron microscopes; and industrial equipment such as industrial robots.

[0085] The photoelectric converter 200 may include a semiconductor device IC, which is a semiconductor chip having a pixel region 214 in which pixels PIX are arranged in an array, as well as a package PKG that houses the semiconductor device IC. The package PKG may include a substrate on which the semiconductor device IC is fixed, a lid made of glass or the like facing the semiconductor device IC, and connecting members such as bonding wires or bumps that connect terminals provided on the substrate to terminals provided on the semiconductor device IC. Any of the detectors 1 according to the first to eighth embodiments can be applied as the photoelectric converter 200.

[0086] The EQP device may further comprise at least one of the following: an optical system OPT, a control unit CTRL, a processing unit PRCS, a display device DSPL, a memory device MMRY, and a mechanical device MCHN. The optical system OPT forms an image on the photoelectric converter 200 and is, for example, a lens, shutter, or mirror. The control unit CTRL controls the operation of the photoelectric converter 200 and is, for example, a semiconductor device such as an ASIC. The processing unit PRCS processes the signal output from the photoelectric converter 200 and is a semiconductor device such as a CPU or ASIC for configuring an AFE (analog front end) or DFE (digital front end). The display device DSPL is an EL display device or liquid crystal display device that displays the information (image) obtained by the photoelectric converter 200. The memory device MMRY is a magnetic device or semiconductor device that stores the information (image) obtained by the photoelectric converter 200. The memory device MMRY is a volatile memory such as SRAM or DRAM, or a non-volatile memory such as flash memory or a hard disk drive. The mechanical device MCHN has a movable part or propulsion part such as a motor or engine. In a camera, the mechanical device MCHN can drive components of the optical system OPT for zooming, focusing, and shutter operation. The device EQP displays signals output from the photoelectric converter 200 on the display device DSPL, or transmits them externally via a communication device (not shown) provided by the device EQP. For this purpose, the device EQP may further include a memory device MMRY and a processing device PRCS, separate from the memory circuit section and arithmetic circuit section included in the peripheral area 215, such as the control / signal processing circuit of the photoelectric converter 200.

[0087] The configurations described in the embodiments and modifications of the present invention described above can be used in any combination. The detector of the present invention may have substrates that, in addition to silicon and germanium, have as the main component, for example, CdTe or CZT (CdZnTe) as the substrates constituting the first member 13 and the second member 14. [Explanation of Symbols]

[0088] 1 detector 10 First area 11 Second area 12 Third area 13. First component 14. Second component 20 Support part 21 Third Member 22 Fourth member 23 Cooler 24a, 24b Fixed part 30 Heat conductive material 31 Penetration 32a, 32b, 32c wiring 33a, 33b, 33c electrodes

Claims

1. A first component for detecting radiation, A second member located around the first member, A third member having a first opening that overlaps with at least a portion of a first region projected onto the first member in a plan view including the first member and the second member, The system includes a fourth member having a second opening that overlaps with at least a portion of the first region in the plan view, and having a higher thermal conductivity than the third member, The first member includes a plurality of pixels for forming an image based on the radiation, The second component includes peripheral circuits including a signal processing circuit and input / output terminals. The first member and the second member are in contact with each other or have an integral structure. The third member has a structure in which a penetrating portion is positioned in a third region that overlaps with the fourth member, outside the second region where the second member is projected in the plan view. The aforementioned through-hole is connected to the fourth member, connected to the second member by a heat-conducting member, and has a higher thermal conductivity than the third member. A detector characterized by the following features.

2. The aforementioned radiation is an electron beam, The region formed by the first opening is a vacuum. The detector according to feature 1.

3. The first member has a thickness of at least 10 μm or more and 100 μm or less in some part. The detector according to claim 1 or 2, characterized by the above.

4. The first member has a thickness of at least 25 μm or more and 75 μm or less in some part. The detector according to claim 3.

5. The heat-conducting member is a conductor and is connected to the ground electrode and fixed at a constant potential. The detector according to any one of claims 1 to 4.

6. The heat conductive member is a heat conductive wiring or bonding wire, and its material is gold, silver, copper, aluminum, or an alloy thereof. The detector according to any one of claims 1 to 5.

7. The heat conductive member is connected to the wiring layer included in the semiconductor layer of the second member. The detector according to any one of claims 1 to 6.

8. The surfaces of the second member to which the heat conductive members are connected and the surfaces of the through-holes are at the same height. The detector according to any one of claims 1 to 7.

9. The aforementioned penetration portion is a thermal conductor or conductive material, and at least a portion of it includes gold, tungsten, copper, titanium, tantalum, aluminum, ruthenium, or carbon graphite. The detector according to any one of claims 1 to 8.

10. The first region, the second region, and the third region each have a rectangular outer perimeter in the plan view, The through-portion is positioned on the outer perimeter of the two sides of the third region that are closer to the outer perimeter of the first region, out of the four outer perimeters of the third region. The detector according to any one of claims 1 to 9.

11. The third member is a printed circuit board or a ceramic substrate. The detector according to any one of claims 1 to 10.

12. The second, third, and fourth members are each connected to the other members by adhesive, grease, gel, solder, or die-bonding material. The detector according to any one of claims 1 to 11.

13. The third member is detachably connected to the fourth member, or the fourth member is detachably connected to the other members on the side opposite to the third member with respect to the fourth member. The detector according to any one of claims 1 to 12.

14. The second member is connected to the third member or the fourth member. The detector according to any one of claims 1 to 13.

15. The first member comprises silicon, germanium, or cadmium. The detector according to any one of claims 1 to 14.

16. A detector according to any one of claims 1 to 15, A radiation source that generates the aforementioned radiation, A control unit for controlling the detector and the radiation source. A radiation detection device having [a certain feature].

17. A detector according to any one of claims 1 to 15, A processing circuit that processes the signal from the detector and A detection system having the following features.

Images