JP2008263190A - Photodetector and radiation detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photodetector and a radiation detecting device which can maintain a high ratio of area occupation by a photoelectric conversion device and can improve a manufacturing yield. <P>SOLUTION: A plurality of radiation receiving modules are provided on a circuit substrate while such a radiation receiving module is provided with a two-dimensional scintillator array 54 and a photoelectric conversion device. The photoelectric conversion device is provided with a substrate 51 and a photodiode array 53 buried into groove 52 formed on the upper surface of the substrate 51. The two-dimensional scintillator array 54 is provided with scintillator elements 59 arranged corresponding to a photodiode element 55 provided on the photodiode array 53, and separators 60 arranged between the scintillator elements 59. The photoelectric conversion device is provided with such a structure, whereby the manufacturing yield is improved, and the occupation area of the photoelectric conversion element, i.e., the photodiode element 55 on the substrate 51 is improved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a technology that includes a photoelectric element that is disposed on a partial region of a substrate upper surface and has a first pad on a light receiving surface, and that outputs an electric signal based on the intensity of light received by the photoelectric element. It is related with the photodetector and radiation detection apparatus which can maintain easily the ratio of the area which a photoelectric element occupies in the plane where this is arrange | positioned, and can be manufactured easily.

  In an X-ray CT apparatus used in a medical institution or the like, an internal structure of a subject is imaged by irradiating the subject with X-rays. Specifically, an X-ray CT apparatus includes an X-ray irradiation source, and a radiation detector having a structure in which X-ray detection units are arranged in a one-dimensional array, which are opposed to each other via an X-ray irradiation source and a subject. Have Here, the detection unit has a function of converting received X-rays into electric signals, and includes a scintillator element that converts X-rays into visible light, and a photodiode that converts visible light into electric signals. The radiation detector receives X-rays that have passed through the subject, and records an electrical signal obtained based on the received X-rays. Then, while maintaining the positional relationship between the X-ray irradiation source and the radiation detector, X-ray reception is repeated by changing the X-ray irradiation angle in various ways. After that, the obtained electrical signal is subjected to processes such as convolution (convolution) and back projection (back projection), so that an image of a cross section (hereinafter referred to as “slice”) of the subject through which X-rays have passed. Reconfigure.

  In particular, in recent years, development of a multi-slice X-ray CT apparatus capable of simultaneously imaging a plurality of slices by one X-ray irradiation has been actively performed. The multi-slice X-ray CT apparatus arranges a plurality of arrayed X-ray detection units corresponding to a plurality of slices, collects X-rays that have passed through each slice, and reconstructs a slice image. Therefore, in the multi-slice X-ray CT apparatus, it is necessary to provide a radiation detection apparatus in which the detection unit is arranged in a two-dimensional array instead of a one-dimensional array. For this reason, the photodiodes constituting the detection unit must also be two-dimensionally arranged.

  In the radiation detector shown in FIG. 24A, a plurality of single-slice one-dimensional photodiode arrays 102 for single slices are arranged in parallel on a substrate 101, and photodiode elements 103 are two-dimensionally arranged. A radiation detector is formed by mounting a two-dimensional scintillator array having a scintillator element corresponding to a photodiode (hereinafter referred to as “prior art 1”). Each photodiode element 103 is electrically connected to a second pad 105 provided on the substrate 101 by a wire bonding 106, and an electric signal output from the photodiode element 103 is a wiring provided on the substrate 101. Is output to the outside of the substrate 101.

  Further, there is known a structure in which a plurality of photodiodes distributed in a matrix and wiring corresponding thereto are integrally formed on the same semiconductor substrate (hereinafter referred to as “Prior Art 2”). A radiation detector is formed by mounting a two-dimensional scintillator array having scintillator elements corresponding to individual photodiodes on the semiconductor substrate in which the photodiodes are formed in this way.

  However, the prior art 1 has the following problems. First, in the prior art 1, a one-dimensional photodiode array 102 is arranged on a flat substrate 101. Therefore, there is a problem that a step is generated by the thickness of the photodiode array 102 between the second pad 105 on the substrate 101 and the photodiode element 103. When the wire bonding 106 is performed in a state where such a step is generated, the position of the second pad 105 needs to be separated from the photodiode element 103 by a predetermined distance in the horizontal direction as shown in FIG. However, by separating the position of the second pad 105 from the photodiode element 103, the interval between the photodiode arrays 102 becomes wider. As a result, the area occupied by the photodiode is relatively small with respect to the entire radiation detector, and there is a problem that the X-ray reception sensitivity is lowered.

  It is also necessary to accurately place the one-dimensional photodiode array 102 on the substrate 101. Therefore, when manufacturing a radiation detector like the prior art 1, a mounting apparatus for fixing the one-dimensional photodiode array on the substrate 101 is newly provided, or a special positioning jig is required. Have a problem.

  Furthermore, since the prior art 1 has a structure in which a two-dimensional scintillator array is directly arranged on a plurality of one-dimensional photodiode arrays 102 arranged, there is a problem that the contact area is small and the mechanical strength is reduced.

  On the other hand, the prior art 2 also has a problem. First, since all photodiodes are formed on one semiconductor substrate, a radiation detector cannot be configured if there is even one defective element among the photodiodes constituting the two-dimensional photodiode array. Other photodiodes built on the semiconductor substrate must be discarded. Here, the individual photodiodes constituting the two-dimensional photodiode array need to be arranged two-dimensionally. Therefore, it is impossible to use a redundant circuit such as that used in a DRAM, and the structure of the prior art 2 has a problem that the yield is very poor.

  Further, the conventional technique 2 has a structure in which necessary wiring is also formed on a semiconductor substrate. Here, since these wirings are provided corresponding to individual photodiodes, the number of wirings increases as the number of photodiodes increases. In particular, when the number of slices is increased, the number of wirings necessary for outputting to the outside increases. Here, in order to suppress the reduction of the area occupied by the photodiode on the semiconductor substrate, it is necessary to narrow the width of each wiring. However, if the wiring is thinned, the electrical resistance increases and the possibility of disconnection Has the problem of becoming higher.

  Note that some of the problems described above are not limited to the case of multi-slices, but also apply to radiation detectors for single slices. For example, in the case of a structure in which a one-dimensional photodiode array is arranged on a substrate, a step between the pad and the photodiode becomes a problem as in the related art 1.

  In addition, the above-described problem is established not only for radiation detectors but also for general photodetectors. In general, the photodetector has a structure in which the scintillator element is excluded from the structure of the radiation detector described above, and is the same as the radiation detector in that a two-dimensional photodiode is arranged. In order to improve the light receiving sensitivity, it is desirable that the area occupied by the photodiode on the substrate is large, but there is a problem that the light receiving area has to be reduced due to the same problem.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and in the photodetector and the radiation detection apparatus, the ratio of the area occupied by the photodiode can be maintained high in the plane where the photodiode is disposed, and can be easily achieved. An object of the present invention is to provide a photodetector and a radiation detection apparatus that can be manufactured.

In order to achieve the above object, the present invention comprises a photoelectric element disposed on a partial region of the upper surface of a substrate and having a first pad on a light receiving surface, and an electric signal based on the intensity of light received by the photoelectric element. A radiation detector component for outputting, a pad forming portion disposed on another region of the substrate, and the first pad formed on the pad forming portion and disposed on the light receiving surface of the photoelectric element And a second pad that is arranged to form the same plane and is electrically connected to the first pad.

In the present invention, the first pad and the second pad are electrically connected by wire bonding.

In the present invention , the present invention further includes a third pad disposed on the back surface of the substrate, and a three-dimensional wiring that electrically connects the second pad and the third pad. .

Further, the present invention is characterized in that the substrate according to any one of the above inventions is an MID substrate, and the three-dimensional wiring is formed by the MID substrate.

In the invention according to any one of the above inventions, the three-dimensional wiring includes a through hole formed through the substrate.

In the invention according to any one of the above inventions, the substrate and the pad forming portion are integrally formed.

Further, the present invention provides the radiation detector component according to the invention described above and the radiation arranged on the light receiving surface of the photoelectric element, and converts the received radiation into light in a wavelength band that the photoelectric element can convert into an electric signal. And a conversion element.

The present invention also includes an MID substrate and a photodiode array placed in contact with the MID substrate, and a pad forming protrusion is provided on the upper surface of the MID substrate on the side in contact with the lower surface of the photodiode array. The upper end surface of the forming projection is the same height as the upper surface of the photodiode array, and a first pad is provided on a portion of the upper surface of each photodiode element of the photodiode array adjacent to the pad forming projection. A second pad is provided on each of the upper end surfaces of the pad forming protrusions adjacent to the first pad, and wire bonding is performed between the corresponding first pad and the second pad. A wiring pattern is provided on the upper surface of the MID substrate that contacts the photodiode array, and is provided on the lower surface of the MID substrate. Is provided with the same number of first terminals and one second terminal as the number of the second pads, and the second pads and the first terminals are electrically connected in a one-to-one relationship. The wiring pattern and the second terminal are electrically connected.

In the present invention , the present invention is characterized in that a groove or a positioning projection for positioning the photodiode array is provided on the upper surface of the MID substrate.

The present invention also includes one MID substrate and a plurality of photodiode elements placed in contact with the MID substrate, and each MID substrate upper surface on the side in contact with the lower surface of each photodiode element. Grooves or positioning protrusions for positioning the photodiode elements are provided, and pad forming protrusions are provided on the upper surface of the MID substrate, and the upper end surfaces of the pad forming protrusions are arranged on the respective photodiode elements. A first pad is provided at a portion adjacent to the pad forming protrusion on the upper surface of each photodiode element and having the same height as the upper surface. Each first pad is provided at the upper end surface of the pad forming protrusion. A second pad is provided in each portion adjacent to the pad, and wire bonding is provided between the corresponding first pad and the second pad, A wiring pattern is provided on the upper surface of the MID substrate in contact with each of the photodiode elements, and the same number of first terminals and one second terminal as the number of the second pads are provided on the lower surface of the MID substrate. Provided, wherein the second pad and the first terminal are electrically connected in a one-to-one relationship, and the wiring pattern and the second terminal are electrically connected. And

Further, the present invention is characterized in that, in the above-mentioned invention, the positioning protrusion has a bank shape and functions as a partition plate between adjacent channels.

Further, the present invention includes the radiation detector component according to the invention described above , and a scintillator array installed so that each element corresponds to the upper surface of the photodiode array of the radiation detector component. Features.

Further, the present invention includes the radiation detector component according to the invention described above , and a scintillator element installed on the upper surface of each photodiode element of the radiation detector component so as to correspond to each element. It is characterized by that.

Further, the present invention is characterized in that a predetermined number of the radiation detectors according to the above invention are arranged vertically and horizontally.

The present invention also provides a scintillator array, a photodiode array disposed on one side surface of the scintillator array in the array alignment direction, and a photodiode array electrically connected to each photodiode element of the photodiode array. Each of the wirings is arranged on the surface of the diode array, and the terminal of each of the wirings is present on the downstream side in the light receiving direction from the contact portion with the scintillator array.

The present invention also provides a scintillator array, a photodiode array disposed on one side surface of the scintillator array in the array alignment direction, and a photodiode array electrically connected to each photodiode element of the photodiode array. Each wiring disposed on the surface of the diode array, and each wiring extends downstream in the light receiving direction from the contact portion with the scintillator array, and then extends in the array alignment direction of the scintillator array, The end of each wiring is present in a lateral position beyond the contact portion with the scintillator array.

The present invention also includes the radiation detector component according to the invention described above, a substrate that supports the radiation detector component, and a wiring provided on the substrate, wherein the wiring on the substrate is the photodiode array. It is electrically connected to the terminal of each wiring arrange | positioned on the surface of this.

Moreover, this invention has the components for radiation detectors as described in said invention , and the board | substrate which supports this components for radiation detectors, It is characterized by the above-mentioned.

Further, the present invention is characterized in that a predetermined number of the radiation detectors according to the above invention are arranged vertically and horizontally.

In addition, the present invention is characterized in that a predetermined number of the radiation detectors according to the above invention are arranged in a direction perpendicular to the array alignment direction of the scintillator array.

According to another aspect of the present invention, there is provided an embedding groove provided in a part of a substrate, a plurality of photoelectric elements arranged in a one-dimensional array, a photoelectric element array embedded in the embedding groove, and the photoelectric element. A first pad disposed on the light receiving surface, and a second pad provided on the substrate corresponding to the first pad and electrically connected to the first pad. To do.

Moreover, the present invention is characterized in that, in the above invention, an optical waveguide is further provided on the upstream side in the light receiving direction from the photoelectric element array.

In the present invention, the optical waveguide guides light incident on a light receiving portion provided on the upper surface of the substrate to a light receiving surface of the photoelectric element having a light receiving area smaller than the light receiving portion. It is characterized by doing.

Further, the present invention is the above invention, wherein the second pad is disposed on the upper surface of the substrate, the thickness of the photoelectric element array and the depth of the groove portion are the same, and the upper surface of the photoelectric element array; The upper surface of the substrate forms the same plane.

In the invention described above, the difference value between the depth of the groove and the thickness of the photoelectric element array is 1 μm or more and 100 μm or less.

Further, the present invention is the invention of the above-mentioned invention, wherein a plurality of the embedding grooves are provided, and the plurality of photoelectric element arrays are arranged in a direction perpendicular to the array alignment direction of the photoelectric element arrays. And

Further, the present invention is the above invention, further comprising a third pad on the back surface of the substrate, wherein the third pad and the second pad are electrically connected by a through hole formed through the substrate. It is characterized by being.

Further, the present invention provides the radiation detector component according to the invention described above and the radiation arranged on the light receiving surface of the photoelectric element, and converts the received radiation into light in a wavelength band that the photoelectric element can convert into an electric signal. And a conversion element.

  In the radiation detector component and the radiation detector of the present invention, an MID substrate is employed to eliminate the step between the upper surface of the photodiode and the surface of the primary substrate, thereby minimizing the space required for wire bonding and providing the output terminal as the primary substrate. Since the radiation detector is miniaturized by connecting the output terminal and the wire bonding pad with a three-dimensional wiring, the radiation detector can be arranged without any gap, and thus, for example, X-ray CT The effective X-ray receiving area per unit area of the apparatus can be maximized and the detection efficiency can be increased.

  In the radiation detector component and the radiation detector of the present invention, each wiring electrically connected to each photodiode element of the photodiode array is connected downstream in the light receiving direction of the radiation detector, that is, on the lower side. Since the unit radiation detector is taken out, it is easy to downsize and produce the unit radiation detector, and the production of the radiation detection apparatus is facilitated, and the radiation detector can be arranged without gaps. The effective X-ray receiving area per unit area can be maximized and the detection efficiency can be increased.

  Furthermore, in the radiation detection apparatus of the present invention, the photodiode array can be easily positioned by forming a groove on the upper surface of the substrate and embedding the photodiode array in the groove. Further, since the first pad arranged on the photodiode array and the second pad arranged on the substrate are arranged so as to form the same plane, the space required for wire bonding is minimized, for example, The effective X-ray receiving area per unit area of the X-ray CT apparatus can be maximized and the detection efficiency can be increased. Furthermore, since the second pad is electrically connected to the third pad provided on the back surface of the substrate by a three-dimensional wiring such as a through hole and outputs an electric signal from the third pad, the effective X-ray receiving area is reduced. In addition to maximizing, a wide area for wiring can be secured.

  Embodiments of the present invention will be described below with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and width of each part, the ratio of the thickness of each part, and the like are different from the actual ones. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included in the drawings.

(Embodiment 1)
First, the radiation detector component according to the first embodiment will be described. FIG. 1 is a schematic perspective view showing a radiation detector component according to the first embodiment in a state where an MID (Molded Interconnected Device) substrate 1 and a photodiode array are separated. 2 is a cross-sectional view taken along the line II of FIG. 1, and FIG. 3A is for the radiation detector according to the first embodiment in a state where the MID substrate 1 and the photodiode array 2 are assembled. It is a schematic perspective view of components. FIG. 3B is a cross-sectional view for explaining the electrical connection of the photodiode array in the assembled state.

  As shown in FIGS. 1 to 3, the radiation detector component according to the first embodiment includes a MID substrate 1 subjected to three-dimensional molding and three-dimensional wiring, and a photodiode array 2 disposed in contact therewith. . A pad forming protrusion 3 is provided on the upper surface of the MID substrate that is in contact with the lower surface of the photodiode array 2, and the upper end surface of the pad forming protrusion 3 is the same height or substantially the same as the upper surface of the photodiode array 2. Are the same height. Although not shown in FIGS. 1 to 3, a groove for positioning the photodiode array or a protrusion for positioning may be provided on the upper surface of the MID substrate. By providing a groove or protrusion for positioning, a special positioning jig is not required when the photodiode array 2 is arranged on the MID substrate 1 in the manufacture of the radiation detector component. Further, the photodiode array 2 can be easily positioned, and the manufacturing process can be simplified.

  A first pad 4 is provided on the upper surface of each photodiode element of the photodiode array 2 at a portion adjacent to the pad forming protrusion 3, and each first pad is provided on the upper end surface of the pad forming protrusion 3. 4 are provided, and second pads 5 are respectively provided at portions adjacent to the first pads 4 on the upper end surface of the pad forming protrusion 3, and the corresponding first pads 4 and the first pads 4 Wire bonding 6 is provided between the two pads 5.

  The electrical connection between the first pad 4 and the second pad 5 will be described with reference to FIG. As described above, the corresponding first pad 4 and second pad 5 are electrically connected by wire bonding 6. Here, the heights of the upper end surface of the pad forming protrusion 3 and the upper surface of the photodiode array 2 are the same or substantially the same as shown in FIG. Therefore, when the wire bonding 6 is provided, it is not necessary to increase the horizontal distance between the first pad 4 and the second pad 5, and the width of the pad forming protrusion 3 can be reduced. From the viewpoint of reducing the horizontal distance between the first pad 4 and the second pad 5, it is sufficient if the heights of the first pad 4 and the second pad 5 are the same or substantially the same. Therefore, as long as this condition is satisfied, the upper surface of the photodiode array 2 and the upper end surface of the pad forming protrusion 3 do not need to be the same or substantially the same height.

  As can also be seen from FIG. 3A, a wiring pattern 7, for example, a cathode wiring pattern 7, is provided on the upper surface of the MID substrate 1 in contact with the photodiode array 2. For example, pin-shaped first terminals 8, such as anode terminals 8, and one pin-shaped second terminal 9, such as cathode terminals 9, are provided in the same number as the two pads 5. Further, the second pad 5 and the first terminal 8, for example, the anode terminal 8, are electrically connected by the wiring 10 formed by MID in a one-to-one relationship, and the wiring pattern 7 such as the cathode wiring is used. The pattern 7 and the second terminal 9, for example, the cathode terminal 9, are electrically connected by wiring arranged in a hole provided in the MID substrate 1, for example. Thereby, the first pads 4 of the individual photodiode elements constituting the photodiode array 2 are electrically connected to the second pads 5 through the wire bonding 6. Further, since the second pad 5 is electrically connected to the first terminal 8 via the wiring 10 as shown in FIG. 2, the first pad 4 of each photodiode element is connected to the first terminal 8. And is electrically connected. On the other hand, each photodiode element has a cathode electrode on the bottom surface, and the electrode is electrically connected to the second terminal 9 via the wiring pattern 7. Here, the cathode electrodes of the individual photodiode elements are short-circuited to each other and connected to the common second terminal 9, but the first pads 4 of the individual photodiode elements are not short-circuited to each other. It is connected to the. Therefore, the electric signals output from the individual photodiode elements can be individually taken out via the corresponding first terminals 8. The same is true even if the anode and the cathode are reversed.

  When the radiation detection apparatus is realized with such a configuration, a region necessary for wiring for detecting an electric signal generated from each photodiode constituting the photodiode array 2 is reduced. In other words, a two-dimensional wiring is applied to the substrate surface as in the past by adopting a three-dimensional wiring structure in which the electrical signal output from the second pad 5 is taken out from the first terminal 8 provided at the lower part of the MID substrate 1. Compared to the case, the gap region between the photodiode arrays can be narrowed. When two-dimensional wiring is provided on the substrate surface as in the prior art, all necessary wiring is arranged in a planar manner in the gap region between the photodiode arrays. Therefore, it is necessary to widen the gap region in order to secure necessary wiring. The radiation detection apparatus according to the first embodiment can occupy a relatively large area of the photodiode as compared with the conventional case, can maximize the effective X-ray reception area, and can increase the detection efficiency. .

  1 to 3, the number of photodiode elements on the upper surface of the radiation detector component, that is, the number of second pads 5 is 8, and the number of pin-shaped terminals on the back surface of the radiation detector component is 9. Since a certain case is illustrated, the interval between the second pads 5 does not match the interval between the pin-shaped terminals and the interval between the holes. Here, as a matter of course, the number of the photodiode elements, the number of the second pads 5 and the number of the first terminals 8 shown in FIGS. 1 to 3 are merely exemplary. Therefore, the structure shown in FIGS. 1 to 3 can be realized regardless of whether the number of photodiodes is more than eight or less.

  In the radiation detector component according to the first exemplary embodiment, the three-dimensional wiring is realized by providing the wiring 10 on the MID substrate 1. However, the three-dimensional wiring is formed by the through-hole penetrating the MID substrate 1 and the pad forming protrusion 3. May be formed. When the through hole is used, it is possible to use a substrate other than the MID substrate as the substrate.

(Modification)
Next, a modification of the radiation detector component according to the first embodiment will be described. In this modification, the photodiode array 2 is not used, but individual photodiode elements separated from each other are arranged on the MID substrate 1.

  That is, the radiation detector component according to the modification is obtained by changing the photodiode array 2 used in the radiation detector component according to the first embodiment shown in FIG. 1 to FIG. 1 is modified to provide grooves or positioning protrusions for positioning each photodiode element on the top surface. This positioning projection has a bank shape and is preferably configured to function as a partition plate between adjacent channels because optical crosstalk due to the transparent adhesive layer used between the photodiode and the scintillator can be reduced.

  Further, since the positioning protrusions or grooves are provided, there is an advantage that no special positioning jig is required when arranging the individual photodiode elements on the MID substrate 1. Further, since the photodiode element can be easily positioned, the radiation detector component can be quickly manufactured at low cost.

(Embodiment 2)
Next, the radiation detector concerning Embodiment 2 is demonstrated. FIG. 4 is a schematic perspective view showing the radiation detector component and the scintillator array according to the first embodiment in a separated state, and FIG. 5 shows the radiation detector component and the scintillator array according to the first embodiment. It is a schematic perspective view of the radiation detector concerning Embodiment 2 of the assembled state.

  As shown in FIGS. 4 and 5, the radiation detector according to the second embodiment includes the radiation detector component according to the first embodiment shown in FIG. 3 and the upper surface of the photodiode array of the radiation detector component. And a scintillator array 11 installed so that each element corresponds. The scintillator array 11 includes a scintillator element 12 and a separator 13. The radiation detector parts and the scintillator array 11 are fixed with an optical adhesive.

(Modification)
In the radiation detector according to the modification of the second embodiment, the photodiode array 2 used in the radiation detector component according to the first embodiment shown in FIGS. 1 to 3 is changed to a plurality of photodiode elements. A radiation detector component according to a modification of the first embodiment, which is modified to provide grooves or positioning protrusions for positioning each photodiode element on the upper surface of the MID substrate 1, and each photodiode element of the radiation detector component And the scintillator element installed to correspond to each element on the upper surface, and the others are substantially the same as the radiation detector according to the second embodiment shown in FIG. 4 and FIG. is there. In the radiation detector according to the modified example, the positioning projection is formed in a bank shape, and is configured to function as a partition plate between adjacent channels, thereby forming a transparent adhesive layer used between the photodiode and the scintillator. This is preferable because optical crosstalk can be reduced.

(Embodiment 3)
Next, the radiation detection apparatus concerning Embodiment 3 is demonstrated. FIG. 6 is a schematic perspective view of the radiation detection apparatus according to the third embodiment obtained by arranging the predetermined number of radiation detectors shown in FIG. 5 in the vertical and horizontal directions, and FIG. 7 shows radiation in which a collimator 14 is further incorporated. It is a schematic perspective view of a detection apparatus. As shown in FIGS. 6 and 7, the radiation detection apparatus has a structure in which radiation detection units each including a combination of a photodiode and a scintillator element are two-dimensionally arranged. Therefore, it can be used not only as a single slice but also as a radiation detection apparatus in a multi-slice X-ray CT apparatus.

  As described above, in the first to third embodiments, the step between the upper surface of the photodiode and the surface of the primary substrate is eliminated to minimize the space required for wire bonding, and the output terminal is located below the primary substrate. Since the radiation detector is miniaturized by arranging and connecting the output terminal and the wire bonding pad with a three-dimensional wiring, as shown in FIG. 6 or FIG. 7, the radiation detector can be arranged without a gap, Therefore, for example, the effective X-ray receiving area per unit area of the X-ray CT apparatus can be maximized, and the detection efficiency can be increased.

(Example)
As the photodiode array 2 shown in FIG. 1, a PIN type silicon photodiode having a length of 13.6 mm, a width of 1.35 mm, and a thickness of 0.3 mm was used. Further, as the MID substrate 1 shown in FIG. 1, the base material is a liquid crystal polymer manufactured by Polyplastics, the length of the entire substrate is 13.6 mm, the thickness is 1.5 mm, the width is 1.5 mm, and the protrusions. The length is 13.6 mm, the height is 0.3 mm, the width is 0.14 mm, the diameter of the pin-shaped output terminal is 0.46 mm, and the wiring is copper in both the wire bonding pad portion, the vertical wiring portion, and the through hole portion. What gave plating, nickel plating, and gold plating was used. As the scintillator shown in FIG. 4, CdWO ₄ having a length of 13.6 mm, a width of 1.5 mm, and a thickness of 2 mm was used.

  The above-described photodiode and MID substrate 1 were assembled to produce a radiation detector component of the present invention, and a scintillator was further incorporated to produce the radiation detector of the present invention. A predetermined number of these radiation detectors were assembled to produce a two-dimensional radiation detection apparatus.

In the present invention, any resin that can be three-dimensionally molded can be used for the MID substrate 1 instead of the above-mentioned liquid crystal polymer manufactured by Polyplastics, and instead of the above plating as the wiring on the MID substrate. Printing of a conductive material and transfer of copper foil can be employed, and instead of a pin-like output terminal, a through hole or a solder bump may be used. The material of the scintillator may be CsI or NaI. Besides, Bi ₄ Ge ₃ O ₁₂ , BaF ₂ , Gd ₂ SiO ₅ , Lu ₂ SiO ₅ and various ceramic scintillators can be exemplified as typical materials. Basically, any element that can convert incident radiation into light may be used.

(Embodiment 4)
Next, the radiation detector component according to the fourth exemplary embodiment will be described. FIG. 8A is a schematic schematic diagram showing the photodiode array 22 and the scintillator array 21 in a separated state in order to show the structure of the radiation detector component according to the fourth embodiment. FIG. 8B is a schematic perspective view of the radiation detector component in which the photodiode array 22 and the scintillator array 21 are brought into contact with each other. As shown in FIG. 8B, in the radiation detector component according to the fourth exemplary embodiment, the photodiode array 22 is disposed on one side surface in the array alignment direction of the scintillator array 21, and the scintillator array 21 and the photodiode are arranged. The array 22 is bonded with an optical adhesive. The scintillator array 21 is composed of individual scintillator elements 23 and separators 24. As shown in FIG. 8A, each of the scintillator arrays 21 is provided at a portion facing the individual scintillator elements 23. The photodiode element 22a is formed. Each photodiode element 22a is electrically connected to a wiring 25. Each wiring 25 is disposed on the surface of the photodiode array, and the end of each wiring 25 is connected to the photodiode array 22. And the scintillator array 21 are present on the downstream side in the light receiving direction, that is, on the lower side in FIG. 8A and FIG.

  In the fourth embodiment, the photodiode array 22 is not located on the downstream side in the light receiving direction with respect to the scintillator array 21, and is disposed on one side surface in the alignment direction of the scintillator array 21. However, each photodiode element 22a included in the photodiode array 22 does not directly convert X-rays into electrical signals. Specifically, each photodiode element 22 a receives visible light radially dispersed from atoms constituting the scintillator element 23 due to X-rays incident on the scintillator array 21. Therefore, even if it is not located downstream in the light receiving direction for X-rays, the photodiode element 22a can receive visible light without any problem.

  As described above, the following advantages are obtained by arranging the photodiode array 22 on one side surface in the array alignment direction with respect to the scintillator array 21. That is, the thickness of the photodiode array 22 is only about several hundred μm at most. Therefore, when the radiation detector component according to the fourth embodiment is viewed from the light receiving direction, the area occupied by the photodiode array 22 can be made very small compared to the area occupied by the scintillator array 21. Thus, when a radiation detector is configured by arranging a plurality of radiation detector parts, the radiation detector parts can be arranged without gaps. Therefore, for example, when used in an X-ray CT apparatus, there is an advantage that an effective X-ray receiving area per unit area of the X-ray CT apparatus can be increased and detection efficiency can be increased.

(Embodiment 5)
Next, the radiation detector concerning Embodiment 5 is demonstrated. FIG. 9 is a schematic cross-sectional view illustrating a state in which a radiation detector is configured by using a plurality of radiation detector components according to the fourth embodiment. As shown in FIG. 9, the radiation detector according to the fifth embodiment is supported by fixing a radiation detector component 27 shown in FIG. 8A on a substrate 28. Here, the substrate 28 has substantially the same length as that of the scintillator array 21 with respect to the length of the scintillator array 21 in the array alignment direction, and substantially the same as that of the scintillator array 21 with respect to the width in the direction perpendicular to the scintillator array alignment direction. Have a width. The height of the substrate 28 is not particularly limited. Wirings 29 are provided on the substrate 28 so as to correspond to the respective photodiode elements.

  Next, a method for assembling the radiation detector shown in FIG. 9 will be described. In the case of assembling the structure shown in FIG. 9, the wiring 29 provided on the substrate 28 is arranged on the surface of the photodiode array 22 of the adjacent radiation detector component 27 so that the wire bonding operation is facilitated. It is electrically connected to the terminal 26 of each wiring by wire bonding 30, and each substrate 28 is provided with a recess at a portion corresponding to the position of the wire bonding 30.

  Here, in order to assemble in the state shown in FIG. 9, the assembly is not performed sequentially in the horizontal direction, but is performed in the vertical direction with the left side of FIG. 9 facing down. That is, the radiation detector component (referred to as 27A for convenience) and the substrate (referred to as 28A for convenience) are arranged side by side in the horizontal direction, and then the radiation detector component 27B on the radiation detector component 27A. Are stacked and fixed, and the terminal 26 of the stacked radiation detector component 27B and the wiring 29 provided on the substrate 28A are electrically connected by wire bonding 30. Then, the substrate 28B is stacked and fixed on the substrate 28A. Thereafter, the radiation detector component 27C is overlapped and fixed, and the terminal 26 of the radiation detector component 27C and the wiring 29 of the substrate 28B are electrically connected by wire bonding 30. This operation is repeated to form a two-dimensional radiation detector using a predetermined number of radiation detector parts.

  Furthermore, if necessary, a two-dimensional radiation detection apparatus having a wider effective area in which two or more sets of the two-dimensional radiation detection apparatus assembled in this manner are arranged in the array alignment direction of the scintillator array 21 can be provided.

  The substrate 28 may be made of a material such as a glass epoxy substrate, a ceramic substrate, a liquid crystal polymer substrate, a substrate made of an epoxy resin mold, or another plastic substrate.

  The radiation detector shown in FIG. 9 includes a plurality of radiation detector parts 27 and a corresponding number of substrates 28. As shown in FIG. 10, the scintillator array is arranged at right angles to the array alignment direction. It is also possible to use a substrate 31 that is continuous in the direction of the length of a predetermined number of radiation detectors. In this case, a groove is provided on the upper surface of the substrate 31 to accommodate a portion of the photodiode array 22 extending below a contact portion between the photodiode array 22 and the scintillator array 21 of the radiation detector component 27, Also, conductive pins 32 are embedded in the substrate 31 so that they can be electrically connected to the terminals 26 of the respective wirings arranged on the surface of the photodiode array 22.

  FIG. 11 is a schematic perspective view of the two-dimensional radiation detection apparatus obtained by connecting and arranging the predetermined number of radiation detectors shown in FIG. 9 or FIG.

  As described above, in the radiation detector component 27 and the radiation detector, each wiring 25 electrically connected to each photodiode element of the photodiode array 22 is connected to the downstream side in the light receiving direction of the radiation detector. That is, since it is taken out on the lower side, the radiation detector can be arranged without gaps as shown in FIG. 11, and therefore, for example, the effective X-ray receiving area per unit area of the X-ray CT apparatus is maximized. The detection efficiency can be increased.

(Embodiment 6)
12 and 13 are schematic perspective views for explaining a radiation detector component and a radiation detector according to the sixth exemplary embodiment of the present invention. Here, FIG. 12 is a schematic perspective view showing the photodiode array 33 and the scintillator array 34 separated from each other, and FIG. 13 is a schematic view showing a state where the photodiode array 33 and the scintillator array 34 are assembled. It is a perspective view.

  As is apparent from FIGS. 12 and 13, in the radiation detector component and the radiation detector according to the sixth embodiment, the photodiode array 33 is arranged on one side surface of the scintillator array 34 in the array alignment direction, and the optical detector is used. It is fixed with an adhesive. A wiring 35 is electrically connected to each photodiode element of the photodiode array 33, and each wiring 35 extends downstream from the contact portion with the scintillator array 34 in the light receiving direction. Extending in the array alignment direction of the array 34, the end of each wiring exists at a side position beyond the contact portion with the scintillator array 34, and forms a terminal 36. A part of the substrate 37 is fixed to the back surface of the photodiode array 33 and has a wiring 38 in another part. The wiring 38 and the terminal 36 are electrically connected by wire bonding.

  With this configuration, the wiring 35 and the terminal 36 drawn from each photodiode element included in the photodiode array 33 have the following advantages. That is, since the photodiode array 33 is disposed on the side surface of the scintillator array 34, only the thickness of the photodiode array 33 affects the effective X-ray receiving area. Therefore, the area of the surface where the photodiode elements of the photodiode array 33 are arranged can be increased. For this reason, the photodiode array 33 can be greatly extended downstream in the light receiving direction. In the photodiode array 33, wirings 35 can be arranged in areas other than areas where the respective photodiode elements are arranged. Therefore, by increasing the area of the photodiode array 33, a region where the wiring 35 and the terminal 36 are arranged can be widened, and the width of the wiring 35 and the area of the terminal 36 can be increased. Therefore, it is not necessary to provide fine wiring as in the prior art, and problems such as disconnection and high resistance can be prevented.

  When producing a radiation detector using the radiation detector component according to the sixth embodiment, as shown in FIGS. 12 and 13, the substrate 37 is placed on the photodiode array 33 in a portion not in contact with the scintillator array 34. Can be provided. As another method, a substrate for supporting the radiation detector component may be provided under the radiation detector component. In this case, as shown in FIG. 9 and FIG. It is not necessary to electrically connect the terminal 26 to the wiring 29 or the conductive pin 32 of the board.

  Further, when a two-dimensional radiation detection apparatus is manufactured using the above-described radiation detector, as shown in the schematic perspective view of FIG. 14, an arbitrary number of the scintillator array 34 is arranged in a direction perpendicular to the array alignment direction. A radiation detector can be connected. Further, by extending the terminals 36 to both sides, two sets can be arranged in the array alignment direction of the scintillator array 34, and the effective X-ray receiving area can be further increased.

(Example)
FIG. 15A is a schematic cross-sectional view of the two-dimensional radiation detection apparatus in a state cut in the array alignment direction of the scintillator array of the radiation detector, and FIG. 15B is perpendicular to FIG. 15A. It is a schematic sectional drawing of the two-dimensional radiation detection apparatus of the state cut | disconnected by this direction. As shown in FIGS. 15A and 15B, the photodiode array 39 is a 24-channel photodiode array (length: 38.05 mm, width: 6.0 mm, thickness: 0.3 mm, light receiving portion size: 1.mm). A PIN type silicon photodiode of 18 mm × 3.8 mm, channel pitch 1.5875 mm) is used, and the scintillator array 40 is 38.05 mm long, 5.0 mm wide, 2.19 mm thick (channel size 1.33 mm × 4). (0.0 mm × 2.0 mm) CdWO ₄ was used. Further, a glass epoxy substrate having a thickness of 0.2 mm is used as the substrate 41, the photodiode and the wiring of the substrate 41 are connected by wire bonding 42, and an output terminal from the substrate wiring has a 1.27 mm pitch, 25 channel connector 43. Was used. Of these 25 channels, 24 channels are anode pins 44 and 1 channel is a cathode pin 45. This 24-channel detector substrate was stacked in five stages, and the space was filled with epoxy resin 46, and a protective cover plate 47 was provided on the side without the substrate, and a 120-channel two-dimensional X-ray detector was prototyped. .

In the present invention, BGA bumps or through-hole terminals may be used instead of pins. Further, the material of the scintillator may be CsI, NaI, LSO other than CdWO ₄ or various ceramic scintillators.

(Embodiment 7)
Next, the radiation detector component according to the seventh embodiment will be described. FIG. 16 is a schematic perspective view of the radiation detection apparatus according to the seventh embodiment. As shown in FIG. 16, the radiation detector component according to the seventh exemplary embodiment includes a substrate 51 having a groove portion 52 having a structure extending in the slice direction, and a photodiode array 53 embedded in the groove portion 52. A two-dimensional scintillator array 54 is arranged on the substrate 51 and the photodiode array 53 embedded in the groove 52 of the substrate. Here, in FIG. 16, the two-dimensional scintillator array 54 is spatially separated from the substrate 51. This is to facilitate the understanding of the structure of the radiation detection apparatus according to the seventh embodiment. Actually, the two-dimensional scintillator array 54 and the substrate 51 are fixed in close contact with a transparent adhesive. A circuit board 64 is disposed under the substrate 51, and the electric circuit disposed on the circuit board 64 is electrically connected to the individual photodiode elements 55 constituting the photodiode array 53.

  The photodiode array 53 includes a plurality of photodiode elements 55, and the plurality of photodiode elements 55 are arranged on the photodiode array 53 so as to have a one-dimensional array arrangement. In the seventh embodiment, the photodiode array 53 is arranged so that the longitudinal direction is the slice direction. Therefore, as shown in FIG. 16, the radiation detection apparatus has four photodiode elements 55 in the channel direction (a direction perpendicular to the slice direction) and three photodiode elements 55 in the slice direction. Become.

  The two-dimensional scintillator array 54 includes a plurality of scintillator elements 59 and separators 60. A plurality of scintillator elements 59 are two-dimensionally arranged corresponding to the photodiode elements 55, and the separator 60 is sandwiched between the boundaries of the individual scintillator elements 59.

The scintillator element 59 is for converting incident X-rays into visible light. The scintillator element 59 is made of CdWO ₄ , CsI, NaI, or the like, and has a function of outputting visible light corresponding to the intensity of incident X-rays to the photodiode element 55. In addition, the outer surface of the scintillator element 59 is painted white, and visible light converted inside the scintillator element 59 is prevented from leaking out of the scintillator element 59. The material constituting the scintillator element 59 may be other than the above materials, and representative examples include Bi ₄ Ge ₃ O ₁₂ , BaF ₂ , Gd ₂ SiO ₅ , Lu ₂ SiO ₅ , and various ceramic scintillators. Basically, any element capable of converting incident radiation into light may be used.

  The separator 60 is for preventing transmission of X-rays and visible light. The separator 60 contains lead (Pb) or the like and has a function of reflecting or absorbing X-rays and visible light. By sandwiching the separator 60 between the scintillator elements 59, crosstalk caused by the same X-rays entering the plurality of scintillator elements 59 when entering the surface of the scintillator elements 59 from an oblique direction is prevented. To do. The same applies to visible light converted from X-rays. That is, by arranging the separator 60, it is possible to prevent optical crosstalk caused by visible light generated inside a scintillator element 59 entering another adjacent scintillator element 59.

  The photodiode element 55 receives visible light converted from X-rays inside the corresponding scintillator element 59, converts the received visible light into an electric signal, and outputs the electric signal to the outside. The photodiode element 55 is composed of a PIN photodiode, has an n-type layer at the bottom, and forms a p-type layer on the surface portion of the photodiode array 53. Furthermore, it has an anode electrode 56 in contact with the p-type layer at the peripheral end of the upper surface, and a cathode electrode in contact with the n-type layer at the bottom.

  Next, an aspect of electrical connection between the photodiode element 55 and the circuit board 64 in the structure of the radiation detecting apparatus according to the seventh embodiment will be described with reference to FIG. FIG. 17 illustrates a part of a cross-sectional structure of the radiation detection apparatus according to the seventh exemplary embodiment. In FIG. 17, the two-dimensional scintillator array 54 and the circuit board 64 are omitted for easy understanding.

  As shown in FIGS. 16 and 17, the photodiode element 55 is embedded in a groove 52 provided in the substrate 51. Here, as is apparent from FIG. 17, the groove 52 has a depth equivalent to the thickness of the photodiode element 55. Therefore, in the state where the photodiode element 55 is embedded, the anode electrode 56 disposed on the upper surface of the photodiode element 55 and the pad 57 disposed on the upper surface of the substrate 51 form the same plane. The anode electrode 56 disposed on the upper surface of the photodiode element 55 and the pad 57 disposed on the upper surface of the substrate 51 are connected by wire bonding 61. Further, a through hole 58 is provided in a broken line region in FIG. 17, and the through hole 58 and the pad 57 are electrically connected.

  The through hole 58 penetrates to the back surface of the substrate 51 and is electrically connected to a pad 63 disposed on the back surface of the substrate 51. Therefore, the electrical signal output from the anode electrode 56 is transmitted to the pad 63 disposed on the back surface of the substrate 51 through the wire bonding 61, the pad 57, and the through hole 58. As shown in FIG. 16, the circuit board 64 is disposed on the back surface of the substrate 51. The pad 63 is electrically connected to an electric circuit provided on the circuit board 64. Solder balls 62 are disposed below the pads 63 in advance, and the pads 63 and an electric circuit provided on the circuit board 64 are electrically connected by the solder balls 62. Specifically, heat is applied in a state where the substrate 51 is temporarily fixed on the circuit board 64 to melt the solder balls 62, thereby ensuring conduction between the pads 63 and the electric circuit. With the above-described structure, the radiation detection apparatus according to the seventh embodiment can output an electrical signal from the photodiode element 55 from the pad 63 provided on the circuit board 64 to the outside.

  Next, a manner of conduction between the cathode electrode provided on the back surface of the photodiode element 55 and the circuit board 64 will be described. FIG. 18 is a top view of the end portion of the substrate 51 constituting the radiation detection apparatus according to the seventh embodiment. FIG. 18 shows a state before the photodiode array 53 is embedded.

  A cathode pad 65 is disposed on the bottom surface of the groove 52 provided in the substrate 51. The cathode pad 65 is disposed over the entire bottom surface of the groove portion 52 so as to be in electrical contact with all of the cathode electrodes provided on the bottom surface of each photodiode element 55 disposed on the photodiode array 53. Yes. Accordingly, the individual photodiode elements 55 are short-circuited with respect to the cathode electrode. However, since the anode electrode is divided for each photodiode element 55, the electrical signal is output when the electrical signal is output. There is no synthesis.

  A cathode through hole 66 is disposed in a partial region of the cathode pad 65. The cathode through hole 66 is for electrically connecting the bottom surface of the groove 52 and the back surface of the substrate 51. Similarly to the connection between the anode electrode and the electric circuit on the circuit board 64 shown in FIG. 17, the cathode through hole 66 is electrically connected to a pad 63 provided on the back surface of the substrate 51. The pads 63 provided on the back surface and the electric circuit on the circuit board 64 are connected via solder balls 62. As described above, the radiation detection apparatus according to the seventh embodiment has a structure for outputting the electrical signal output from the photodiode element 55 to the outside.

  Next, the operation of the radiation detection apparatus according to the seventh exemplary embodiment will be described. FIG. 19 is a schematic diagram illustrating a state in which X-rays enter the radiation detection apparatus according to the seventh embodiment.

  X-rays incident from the upper surface of the scintillator element 59 are converted into visible light inside the scintillator element 59. Here, the conversion efficiency into visible light is proportional to the energy of X-rays. Here, X-rays incident at an angle other than perpendicular to the upper surface of the scintillator element 59 are all converted to visible light before reaching the side surface of the scintillator element 59, or have reached the side surface as X-rays. However, since most of the light is absorbed or reflected by the separator 60, it hardly enters the other adjacent scintillator elements. The same applies to the visible light converted from the X-rays, and the visible light does not enter other scintillator elements.

  Then, the visible light converted from the X-rays enters the photodiode element 55. The photodiode element 55 converts the received visible light into an electrical signal. Specifically, an electrical signal is generated based on the generation of an electron / hole pair in the photodiode element 55 by incident light. Here, the intensity of the electrical signal is proportional to the energy value of the visible light received. Since the energy value of the visible light is proportional to the intensity of the X-ray light incident on the scintillator element 59 as described above, the intensity of the electric signal output from the photodiode element 55 is the X-ray incident on the scintillator element 59. Obviously, it is proportional to the intensity of the light. The electrical signal output from the photodiode element 55 is transmitted to the back surface of the substrate 51 through the through hole 58 and the cathode through hole 66 and output to the outside through the circuit substrate 64. Although FIG. 19 shows a mode in which the current I is output as an example of the electrical signal, the present invention is not limited to this, and the electrical signal may be output in the form of a voltage change or the like.

  As described above, by having a structure that outputs an electrical signal corresponding to the intensity of the X-rays incident on each scintillator element 59, the radiation detection apparatus according to the seventh embodiment can detect X-rays related to the incident position. An intensity distribution can be obtained.

  The radiation detection apparatus according to the seventh embodiment has a structure in which a plurality of photodiode arrays 53 in which photodiode elements 55 are arranged in a row are arranged. Therefore, there is an advantage that the yield as a product is improved. That is, when the two-dimensional photodiode array as shown in FIG. 16 is formed on the same substrate, the remaining 11 elements are present because of the presence of any one of the 12 photodiode elements. This photodiode element cannot be used in a radiation detection apparatus.

  On the other hand, in the radiation detection apparatus according to the seventh embodiment, even if one photodiode element 55 is defective, only the photodiode array 53 having the defective photodiode element 55 is replaced with another one. The remaining nine photodiode elements can be used effectively. In particular, radiation detectors used in recent X-ray CT scanning apparatuses have been increasingly multi-channeled and multi-sliced, so the number of photodiode elements to be arranged tends to increase. Therefore, the radiation detection apparatus according to the seventh embodiment in which a plurality of one-dimensional photodiode arrays 53 are arranged can be expected to have a higher yield.

  Further, a structure in which the photodiode array 53 having a one-dimensional arrangement is embedded in the groove 52 is employed. This has the following advantages. First, since the width of the groove 52 and the width of the photodiode array 53 are the same, alignment can be performed easily. Therefore, when the photodiode array 53 is disposed on the substrate 51, it is only necessary to position the photodiode array 53 in the slice direction. Further, when a projection or groove is newly provided for positioning in the slice direction, the photodiode array 53 can be easily arranged without any steps such as position adjustment. For this reason, in the radiation detection apparatus concerning this Embodiment 7, manufacture is easy and can be manufactured rapidly.

  Further, in the seventh embodiment, the thickness of the photodiode array 53 and the depth of the groove 52 are substantially the same value. This has the advantage that the area required for the wire bonding 61 can be reduced.

  In order to output an electric signal from the individual photodiode elements 55 arranged on the photodiode array 53 to the outside, the anode electrode 56 and the cathode electrode of the photodiode element 55 are electrically connected to the electrodes provided on the substrate. It is necessary to make it. Here, when the photodiode array is disposed on a flat plate, there is a problem that a step between the anode electrode and the pad disposed on the substrate cannot be avoided. When there is a step, it is necessary to increase the horizontal distance necessary for wire bonding. However, in the seventh embodiment, there is no step between the anode electrode 56 and the pad 57, or even if there is only a small step, it is not necessary to increase the horizontal distance as in the conventional case.

  Furthermore, the seventh embodiment has a structure in which the anode electrode 56 disposed on the upper surface of the photodiode element 55 is three-dimensionally drawn using the through hole 58. As a result, the width of the bank portion of the substrate 51 located between the adjacent photodiode arrays 53 can be reduced. Conventionally, since necessary wiring has been provided on the upper surface of the substrate, it has been necessary to reduce the width of the wiring or increase the width between the photodiode arrays 53 as the number of channels and the number of slices are increased. .

  On the other hand, in the seventh embodiment, the anode electrode 56 is three-dimensionally drawn out, and there is no need to provide wiring on the upper surface of the substrate 51. Therefore, even if the number of photodiode elements 55 is increased by multi-channel and multi-slicing, the distance between the photodiode arrays 53 need not be wide, and the distance can be kept constant. Specifically, the width of the bank portion of the substrate 51 located between the photodiode arrays 53 can be made as narrow as possible as long as the width necessary for wire bonding and the width necessary for the through hole can be secured. Therefore, the area occupied by the photodiode element 55 in a plane perpendicular to the X-ray incident direction in the radiation detection apparatus can be widened, and a highly sensitive radiation detection apparatus can be realized.

  In the seventh embodiment, when the anode electrode 56 is pulled out in the vertical direction on the substrate 51 and connected to the circuit board 64, an electric signal is output to the outside by an electric circuit on the circuit board 64. In this case, since it is possible to configure a circuit on the circuit board 64 and also in a region located below the photodiode array 53, compared with the case where an electric circuit is arranged on the upper surface of the substrate 51, There is also an advantage that the area used for the circuit can be increased. Therefore, it is not necessary to provide fine wiring, and the risk of high resistance or disconnection can be avoided.

  Further, in the seventh embodiment, it is easy to provide the groove 52 on the substrate 51. For example, the groove 52 can be formed by cutting the surface of the substrate 51 using a dicing saw used for separating the semiconductor chips. Therefore, the seventh embodiment also has an advantage that the radiation detection apparatus can be easily manufactured. In addition, since the photodiode array 53 can be positioned with a simple structure, the radiation detection apparatus can be easily manufactured in this respect.

  In the seventh embodiment, the pads 63 provided on the back surface of the substrate 51 and the circuit board 64 are electrically connected using the solder balls 62. For this reason, between the board | substrate 51 and the circuit board 64 can be fixed easily, and a radiation detection apparatus can be manufactured easily.

  Note that in Embodiment 7, a structure having three slices and four channels per slice is used, but a structure in which a plurality of photodiode elements are used in the slice direction for the same channel of a predetermined slice may be used. .

  In the seventh embodiment, the longitudinal direction of the photodiode array 53 is the slice direction and the short direction is the channel direction. However, the respective directions may be reversed. That is, the radiation detection apparatus according to the seventh embodiment can be configured even if the photodiode array 53 is arranged so that the longitudinal direction thereof is parallel to the channel direction.

  In FIG. 16 and FIG. 17, the wire bonding 61 connecting the anode electrode 56 and the pad 57 has an arch shape, but may be configured to be connected in a straight line. As described above, since there is no step between the upper surface of the substrate 51 and the upper surface of the photodiode element 55, there is no fear of disconnection or the like even if wire bonding is performed linearly.

  Further, the horizontal cross-sectional shape of the through hole 58 and the cathode through hole 66 may not be circular. For example, when the cross-sectional shape is an ellipse having a major axis in the longitudinal direction of the photodiode array 53, the outer circumference can be made larger, so that when passing through a through hole compared to a circular shape, Electric resistance can be suppressed.

  In the seventh embodiment, the PIN photodiode is arranged so that the p-type layer comes to the upper surface and the anode electrode 56 is exposed on the upper surface. However, the n-type layer is the upper surface, and the cathode electrode is It is good also as a structure exposed to an upper surface. Even with such a structure, the radiation detection apparatus can obtain the same advantages.

  In addition, as the photodiode element 55 included in the photodiode array 53, a PIN type photodiode is used in the seventh embodiment. However, the present invention is not limited to this, and a photodiode formed of a PN junction or a Schottky photodiode is used. Heterojunction photodiodes and avalanche photodiodes may also be used. In addition, a circuit element other than a photodiode may be used as long as it can perform photoelectric conversion. For example, a photo resistor whose electrical resistance changes according to the intensity of the irradiated light may be used instead of the photodiode.

  Further, in the seventh embodiment, the circuit board 64 is arranged under the board 51, but the circuit board 64 can be omitted. For example, a circuit pattern may be formed in advance on the back surface of the substrate 51, and pads for output to the outside may be arranged on the side surface of the substrate 51. In this case, the circuit board 64 and the solder balls 62 can be omitted.

(Embodiment 8)
Next, a radiation detection apparatus according to Embodiment 8 will be described. FIG. 20 is a schematic cross-sectional view illustrating the structure of the radiation detection apparatus according to the eighth embodiment. Here, in FIG. 20, for easy understanding, the two-dimensional scintillator array disposed on the substrate 79 and the circuit substrate disposed below the substrate 79 are omitted.

  In the radiation detection apparatus according to the eighth exemplary embodiment, the groove 80 provided on the upper surface of the substrate 79 is formed deeper than the seventh exemplary embodiment. Regarding other points, unless otherwise specified, it has the same structure as that of the seventh embodiment and exhibits the same effect.

  In the eighth embodiment, the depth of the groove 80 is set larger than the thickness of the photodiode array 69 embedded in the groove 80. This produces the following advantages.

  In general, since the photodiode array 69 embedded in the groove 80 is manufactured under the same conditions, it is assumed that the thickness does not differ. However, in reality, the thickness may differ depending on the individual photodiode array 69. In particular, when a photodiode element is formed by performing epitaxial growth on a semiconductor substrate, it is difficult to perform complete epitaxial growth and a difference in thickness may occur.

  Thus, when the thicknesses of the photodiode arrays 69 are different from each other, the upper surface formed by the substrate 79 and the embedded photodiode array 69 cannot form a smooth plane. When a two-dimensional scintillator array is arranged on such an upper surface, the stability of the two-dimensional scintillator array may be impaired. A structure in which a gap generated between the substrate 79 and the two-dimensional scintillator array is filled with a transparent adhesive layer is also possible. In that case, however, optical crosstalk due to light leakage occurring in the gap portion filled with the transparent adhesive layer occurs. It becomes a problem.

  Therefore, in the eighth embodiment, the depth of the groove 80 is made larger than the thickness of the photodiode array 69. Then, the upper surface of the substrate 79 and the two-dimensional scintillator array are fixed in close contact with each other via a transparent adhesive. Here, the upper surface of the photodiode array 69 is not in contact with the two-dimensional scintillator array. Since the upper surface of the substrate 79 is formed on the same plane except for the groove 80, the problem that a smooth plane as described above cannot be formed can be prevented. In addition, since no gap is generated between the upper surface of the substrate 79 and the two-dimensional scintillator array, the problem of optical crosstalk can be prevented.

  Here, the difference between the depth of the groove 80 and the thickness of the photodiode array 69 is preferably 1 μm or more and 100 μm or less. The reason why the thickness is 1 μm or more is that if the difference is too small, the difference in thickness of the individual photodiode arrays 69 may not be absorbed. Also, the reason why the thickness is set to 100 μm or less is that the step between the anode electrode 56 of the photodiode element of the photodiode array 69 and the pad 68 disposed on the upper surface of the substrate 79 cannot be ignored when the thickness is larger than 100 μm. This is because it is necessary to increase the distance between the photodiode arrays 69 in order to perform wire bonding.

(Embodiment 9)
Next, Embodiment 9 will be described. FIG. 21 is a schematic perspective view showing a configuration of a substrate 70 constituting the radiation detection apparatus according to the ninth embodiment and a photodiode array 73 embedded in the substrate 70. The radiation detection apparatus according to the ninth exemplary embodiment includes a second groove 72 on the top of the first groove 71 provided to embed the photodiode array 73. As shown in FIG. 21, the second groove 72 has a structure in which a wide opening is formed in the channel direction in the upper part and the width becomes narrower as it goes down in the light receiving downstream direction. On the other hand, since the first groove 71 is formed to embed the photodiode array 73, the longitudinal section has a rectangular shape. Note that points not particularly mentioned are the same as those of the radiation detection apparatus according to the seventh embodiment and have the same functions. For example, in the ninth embodiment, a circuit board is disposed under the substrate 70, and the circuit board and the pad 63 provided on the back surface of the circuit board are electrically connected via the solder balls 62 and output to the outside. It has a structure.

  FIG. 22 is a schematic cross-sectional view illustrating the structure of the radiation detection apparatus according to the ninth embodiment. The photodiode array 73 is embedded in a groove portion 71 formed in the substrate 70, and an anode electrode 74 is provided on the inclined surface constituting the second groove portion for each photodiode element arranged on the photodiode array 73. It is electrically connected to the provided pad 75 via wire bonding. Further, a through hole 76 that penetrates the substrate 70 from the second groove portion 72 in the vertical direction is disposed, and the through hole 76 is electrically connected to the pad 75. Further, a pad 63 is provided on the back surface of the substrate 70 and is electrically connected to the through hole 76. Therefore, an electrical signal output from each photodiode element arranged in the photodiode array 73 is output to the back surface of the substrate 70 through the pad 75, the through hole 76, and the pad 63.

  The second groove 72 has a function as a waveguide that collects visible light converted from X-rays in the scintillator element 59 in the photodiode array 73. That is, due to the presence of the second groove portion 72, visible light converted from X-rays by the scintillator element 59 is appropriately reflected on the slope forming the second groove portion 72, and the photodiode elements included in the photodiode array 73. And is received by the individual photodiode elements. Here, in order to increase the reflectance of visible light in the second groove 72 and to make the visible light efficiently enter the photodiode element, the second groove 72 is formed of a multilayer composed of a plurality of films having different refractive indexes. Structures may be stacked.

  The advantage by having the 2nd groove part 72 is demonstrated. The radiation detection apparatus according to the ninth exemplary embodiment has a structure in which visible light is collected by the second groove portion 72. Therefore, the area of the light receiving portion of the photodiode element can be made smaller than the X-ray receiving area on the upper surface of the scintillator element 59. For this reason, the photodiode element for comprising a radiation detection apparatus can be reduced in size, and manufacturing cost can be reduced. This is because the number of photodiode elements that can be manufactured from one wafer can be increased by reducing the number of photodiode elements per one.

(Modification)
Next, a radiation detection apparatus according to a modification of the ninth embodiment will be described. FIG. 23 is a schematic top view showing a substrate 77 constituting a radiation detection apparatus according to a modification and a photodiode 78 arranged on the substrate 77. Here, the two-dimensional scintillator array is arranged above the substrate 77, and the circuit board is arranged below the substrate 77, as in the ninth embodiment. In the modified example, it is assumed that the photodiode arrays 78 are not disposed on the substrate but are separated from each other. Here, the photodiode 78 is embedded in the first groove provided in the substrate 77 as in the ninth embodiment. A second groove having a function as a waveguide is formed above the first groove in which the photodiode 78 is embedded.

  In the modification, the second groove portion has a slope not only in the slice direction but also in the channel direction, and functions as a waveguide that focuses incident visible light on the photodiode 78. For this reason, visible light can be more efficiently collected in the photodiode 78, and the photodiode 78 can be further reduced in size.

  As mentioned above, although this invention was demonstrated over Embodiment 1-9, this invention is not limited to these Embodiment, Those skilled in the art is equivalent to various modifications using these Embodiment. Is possible. For example, in Embodiments 1 to 3 and Embodiments 7 to 9, it is possible to obtain a photodetector as a configuration excluding the scintillator element or the scintillator element array. According to the present invention, since the area occupied by the photodiode element can be increased, it is possible to provide a photodetector having a wide light receiving area and high sensitivity by applying the structure of the present invention to the photodetector. it can.

  In the first to ninth embodiments, the pad provided on the upper surface of the photodiode element and the substrate are electrically connected by wire bonding. However, the present invention is not limited to this. For example, the connection may be made by a flip chip method, or the connection may be made by a TAB (Tape Automated Bonding) method. In the first to ninth embodiments, the pad provided on the upper surface of the photodiode element and the pad provided on the substrate form the same plane, and thus can be easily electrically connected by this method. .

  In Embodiments 7 to 9, the photodiode element converts visible light into an electrical signal. However, the photodiode element may be configured to irradiate the photodiode element with light of other wavelengths. Specifically, if a Schottky photodiode is used, it is possible to perform photoelectric conversion on light in a wavelength region shorter than the visible light region. When a photodiode is formed by InSb, up to the nitrogen temperature. By lowering, it is possible to obtain a photoelectric element having sensitivity to the infrared region. By combining with a scintillator element that converts X-rays into light having such a wavelength, the above-described radiation detector component, radiation detector, and radiation detection apparatus can be configured.

  Furthermore, in the seventh to ninth embodiments, one photodiode array is embedded in one groove portion, but a structure in which a plurality of photodiode arrays arranged in the slice direction may be embedded is also possible. Further, a structure may be adopted in which a plurality of individual photodiode elements are embedded in one groove portion instead of one photodiode array. In that case, it is desirable to provide protrusions or grooves for positioning individual photodiode elements in the grooves.

It is a schematic perspective view which shows the state for radiation detector parts concerning Embodiment 1 in the state which separated the MID board | substrate and the photodiode array. It is sectional drawing in the II line | wire of FIG. (A) is a schematic perspective view of the component for radiation detectors according to the first exemplary embodiment in a state where the MID substrate and the photodiode array are assembled, and (b) is an electrical connection of the photodiode array in the assembled state. It is sectional drawing which shows the aspect of. FIG. 6 is a schematic perspective view of the radiation detector according to the second exemplary embodiment with the radiation detector component and the scintillator array separated from each other. It is a schematic perspective view of the radiation detector concerning Embodiment 2 in the state which assembled the components for radiation detectors and the scintillator array. It is a schematic perspective view which shows the structure of the radiation detection apparatus concerning Embodiment 3. FIG. In the radiation detection apparatus concerning Embodiment 3, it is a schematic perspective view which shows the structure at the time of arrange | positioning a collimator further. (A) is the schematic perspective view which shows the state for the radiation detector components concerning Embodiment 4 in the state which isolate | separated the photodiode array and the scintillator array, (b) is the state which assembled the components for radiation detectors. It is a schematic perspective view shown. FIG. 6 is a schematic cross-sectional view showing a structure of a radiation detector according to a fifth exemplary embodiment. FIG. 10 is a schematic cross-sectional view showing the structure of a modification of the radiation detector according to the fifth exemplary embodiment. FIG. 9 is a schematic perspective view showing a structure of a radiation detection apparatus according to a fifth exemplary embodiment. In the radiation detector concerning Embodiment 6, it is a schematic perspective view shown in the state which isolate | separated the photodiode array and the scintillator array. It is a schematic perspective view which shows the structure of the radiation detector concerning Embodiment 6. It is a schematic perspective view which shows the structure of the radiation detection apparatus using the radiation detector concerning Embodiment 6. FIG. (A), (b) is a schematic sectional drawing of the radiation detection apparatus obtained in an Example. In the radiation detection apparatus concerning Embodiment 7, it is a schematic perspective view shown in the state which isolate | separated the two-dimensional scintillator array. In the radiation detection apparatus concerning Embodiment 7, it is a schematic sectional drawing which shows the outline | summary of electrical connection. In the radiation detection apparatus concerning Embodiment 7, it is a schematic top view which shows the structure of a board | substrate. FIG. 10 is a schematic cross-sectional view showing the operation of the radiation detection apparatus according to the seventh exemplary embodiment. FIG. 9 is a schematic cross-sectional view showing the structure of a radiation detection apparatus according to an eighth embodiment. It is a schematic perspective view which shows the structure of the radiation detection apparatus concerning Embodiment 9. FIG. FIG. 10 is a schematic cross-sectional view showing the operation of the radiation detection apparatus according to the ninth exemplary embodiment. FIG. 20 is a schematic top view showing the structure of a radiation detection apparatus according to a modification example of the ninth embodiment. (A) is a schematic perspective view which shows the structure of the radiation detection apparatus concerning a prior art, (b) is a schematic sectional drawing shown about the aspect of the electrical connection of the radiation detection apparatus concerning a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 MID board | substrate 2, 22, 33, 39, 53, 69, 73 Photodiode array 3 Protrusion for pad formation 4 1st pad 5 2nd pad 6, 30, 42, 61, 67 Wire bonding 7 Wiring pattern 8 Pin-shaped First terminal 9 Pin-shaped second terminal 10, 25 Wiring 11, 21, 34, 40 Scintillator array 12, 23 Scintillator element 13, 24 Separator 14 Collimator 26, 36 Terminal 27 Radiation detector parts 28, 31, 37, 41 , 51, 70, 77, 79 Substrate 29, 35, 38 Wiring 32 Conductive pin 43 25 channel connector 44 Anode pin 45 Cathode pin 46 Epoxy resin 47 Protective cover plate 52, 80 Groove 54 Two-dimensional scintillator array 55 Photodiode element 56 Anode electrodes 57, 63, 8,75 pads 58,76 through hole 59 scintillator elements 60 separator 62 solder balls 64 circuit board 65 cathode pad 66 cathode through hole 71 first groove 72 second groove 74 anode electrode 78 photodiode

Claims (7)

  A photodetector in which a plurality of photoelectric converters are arranged on a circuit board having a predetermined electric circuit and input terminals,
  The photoelectric converter is
  A substrate comprising an output terminal corresponding to the input terminal and an input pad electrically connected to the output terminal on the surface;
  An output electrode that is disposed so as to form substantially the same plane as the input pad, and is electrically connected to the input pad, and a photoelectric device that is electrically connected to the output electrode and outputs an electrical signal corresponding to the received light intensity. A two-dimensional photoelectric conversion unit in which a plurality of one-dimensional photoelectric conversion element arrays in which conversion elements are arranged one-dimensionally are arranged in a direction perpendicular to the element arrangement direction;
  A photodetector comprising:   The photodetector according to claim 1, wherein the substrate includes a plurality of groove portions for embedding the one-dimensional photoelectric conversion element array.   The substrate is
  A convex portion disposed on a partial region of the upper surface and having the input pad on the upper end surface; and the one-dimensional photoelectric conversion element array receiving region disposed on another region of the upper surface;
  An MID board having an output terminal electrically connected to the input pad;
  The photodetector according to claim 1, further comprising: a plurality of light emitting diodes arranged in a direction perpendicular to an element arrangement direction of the one-dimensional photoelectric conversion element array.   The photodetector according to claim 1, wherein the input pad and the output electrode are electrically connected by wire bonding.   The photodetector according to any one of claims 1 to 4,
  A light converter having a plurality of light conversion elements arranged corresponding to a two-dimensional photoelectric conversion unit of the light detector and converting received radiation into light having a wavelength detectable by the light detector;
  A shielding layer disposed between the light conversion elements;
  A radiation detection apparatus comprising:   A radiation detection apparatus in which a plurality of radiation detectors are arranged on a circuit board having a predetermined electrical circuit and input terminals,
  The radiation detector is
  A one-dimensional light conversion element array in which light conversion elements that convert received radiation into light of a predetermined wavelength are arranged one-dimensionally;
  A one-dimensional photoelectric conversion element array that is arranged on one side surface in the array alignment direction with respect to the one-dimensional light conversion element array, and in which photoelectric conversion elements are arranged in a one-dimensional manner corresponding to the light conversion elements;
  A radiation detection apparatus characterized in that a plurality of arrays are arranged in a direction perpendicular to the array alignment direction.   The one-dimensional photoelectric conversion element array has a structure extending downstream in the receiving direction, and includes a lead-out wiring on the extended region and an external output terminal electrically connected to the lead-out wiring. The radiation detection apparatus according to claim 6.

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