JP2020177033A - Radiation detector - Google Patents

Abstract

To provide a radiation detector which achieves both miniaturization of a device and enlargement of an effective area of a scintillator layer, and also achieves improvement in productivity.SOLUTION: A radiation detector 1 includes: a photoelectric conversion element array 7; a scintillator layer 8; a resin frame 9; and a protective film 13. An outer edge 13a and a groove part 9a of the protective film 13 are in a state of being processed by a laser beam. A peripheral edge part 8b of the scintillator layer 8 has a tapered shape whose height gradually decreases toward the outside of the scintillator layer 8. A distance D1 between an inner edge E1 of the resin frame 9 and an outer edge E3 of the scintillator layer 8 is equal to or less than one mm.SELECTED DRAWING: Figure 2

Description

The present invention relates to a radiation detector.

Conventionally, as shown in Patent Document 1 below, a radiation detector (radiation detection element) in which a scintillator layer having a columnar crystal structure is formed on a sensor panel (light receiving portion) is known. In this radiation detector, a plurality of bonding pads electrically connected to the light receiving element are arranged outside the light receiving portion. Further, when viewed from the stacking direction of the scintillator layer, a resin frame is formed so as to pass between the scintillator layer and the bonding pad and surround the scintillator layer. The scintillator layer is covered with a moisture-resistant protective film, and the outer edge of the moisture-resistant protective film reaches on the resin frame.

A radiation detection device provided with such a radiation detector is in demand for a portable device in addition to a stationary device. Therefore, it is required to reduce the size and weight of the radiation detection device. Therefore, it is required to reduce the size and weight of the radiation detector constituting the radiation detection device. In order to reduce the size of the radiation detector, the resin frame should be made as small as possible and the distance between the resin frame and the outer edge of the scintillator layer should be as short as possible to reduce the area (effective area) of the scintillator layer in the inner region of the resin frame. It is preferable to take as large as possible.

Japanese Patent No. 3077941

By the way, in the manufacturing process of the radiation detector described in Patent Document 1, the moisture-resistant protective film formed on the resin frame is cut by a cutter along the resin frame. However, in a state where the resin frame is downsized and the distance between the resin frame and the outer edge of the scintillator layer is shortened, the work of cutting the moisture-resistant protective film with a cutter requires considerable skill, so that the productivity and manufacturing cost are high. There is room for improvement from the perspective of.

Therefore, an object of the present invention is to provide a radiation detector in which both the miniaturization of the apparatus and the large effective area of the scintillator layer are achieved and the productivity is improved.

The method for manufacturing a radiation detector according to one aspect of the present invention is a light receiving portion including a plurality of photoelectric conversion elements arranged one-dimensionally or two-dimensionally, and a light receiving portion electrically connected to the photoelectric conversion element and outside the light receiving portion. From the step of preparing a photoelectric conversion element array having a plurality of arranged bonding pads and laminating the scintillator layer for converting radiation into light on the photoelectric conversion element array so as to cover the light receiving portion, and from the stacking direction of the scintillator layer. When viewed, a step of forming a resin frame on the photoelectric conversion element array so as to separate from the scintillator layer and the bonding pad, pass between the scintillator layer and the bonding pad, and surround the scintillator layer, and at least photoelectric conversion. By forming a protective film so as to cover the entire surface on the side where the scintillator layers of the element array are laminated, and by irradiating the laser beam along the substantially central portion of the resin frame while scanning the laser beam in a single stroke manner. The process of cutting the protective film and cutting and removing a part of the resin frame, removing the outer part of the protective film and forming a groove in the substantially central part of the resin frame, and the resin so as to cover the outer edge of the protective film. It has a step of forming a coating resin layer along the frame.

In the above method for manufacturing a radiation detector, in the step of removing the outer portion of the protective film and forming a groove portion in a substantially central portion of the resin frame, the outer edge and the groove portion of the protective film are corner portions when viewed from the stacking direction. The laser beam may be scanned so as to form an arc shape that is convex outward.

The radiation detector according to one side has a light receiving unit including a plurality of photoelectric conversion elements arranged in one or two dimensions, and a plurality of bonds electrically connected to the photoelectric conversion element and arranged outside the light receiving unit. A scintillator layer having a pad, a scintillator layer laminated on the photoelectric conversion element array so as to cover a light receiving portion, and converting radiation into light, and a scintillator layer and a bonding pad when viewed from the stacking direction of the scintillator layer. It has a resin frame formed on the photoelectric conversion element array so as to pass between the scintillator layer and the bonding pad and surround the scintillator layer, and an outer edge that covers the scintillator layer and is located on the resin frame. With a protective film, the first distance between the inner edge of the resin frame and the outer edge of the scintillator layer is shorter than the second distance between the outer edge of the resin frame and the outer edge of the photoelectric conversion element array. The outer edge of the protective film and the corresponding region of the resin frame corresponding to the outer edge of the protective film are in a state of being processed by laser light.

In the radiation detector according to one side, the protective film on the resin frame is processed by laser light. Since processing by laser light does not require skill as compared with cutting by a cutter, productivity can be improved. Further, since the protective film can be cut with high accuracy by using the laser beam, the resin frame can be miniaturized. Further, since the resin frame is formed so as to be separated from the scintillator layer and the bonding pad, it is possible to suppress an adverse effect on the scintillator layer and the bonding pad due to the laser beam during manufacturing. On the other hand, by arranging the resin frame close to the scintillator layer, the effective area of the scintillator layer can be increased. Therefore, according to the radiation detector according to the present invention, it is possible to achieve both miniaturization of the apparatus and an increase in the effective area of the scintillator layer, and to improve productivity.

In the radiation detector, the outer edge of the protective film and the corresponding region may have a fine wavy shape when viewed from the stacking direction. As a result, when the protective film on the resin frame is covered with the coating resin, the contact area between the outer edge and the corresponding area of the protective film and the coating resin increases, so that the outer edge and the corresponding area of the protective film and the coating resin are adhered to each other. It can be made stronger.

In the radiation detector, the height of the corresponding region may be 1/3 or less of the height of the resin frame. As a result, the adverse effect of the laser beam on the photoelectric conversion element array located below the resin frame can be suppressed more effectively.

In the radiation detector, the ratio of the second distance to the first distance may be 5 or more. With such a ratio, it is possible to more effectively suppress the adverse effect of the laser beam during manufacturing on the bonding pad, secure the effective area of the scintillator layer, and reduce the size of the apparatus.

In the radiation detector, the resin frame is formed so that the central portion is higher than both edge portions, and the height of the resin frame may be lower than the height of the scintillator layer. As a result, the resin frame can be miniaturized, and the adverse effect of the laser beam during manufacturing on the scintillator layer can be suppressed more effectively.

In the radiation detector, the width between the inner edge of the resin frame and the outer edge of the resin frame may be 900 μm or less, and the height of the resin frame may be 450 μm or less. As a result, the device can be further miniaturized while securing the effective area of the scintillator layer by downsizing the resin frame.

In the radiation detector, the outer edge and the corresponding region of the protective film processed by the laser beam may be formed in a substantially rectangular ring shape having convex arcuate corners on the outside when viewed from the stacking direction. According to the above-mentioned radiation detector, by forming the corners (corners of the four corners) of the protective film into an outwardly convex arc shape (so-called R shape), the protective film is peeled off from the resin frame at the corners. Can be suppressed.

The radiation detector may further include a coating resin layer arranged along the resin frame so as to cover the outer edge of the protective film. By providing such a coating resin layer, the outer edge of the protective film can be sandwiched and fixed between the resin frame and the coating resin layer. As a result, it is possible to prevent the protective film from peeling off from the resin frame at the outer edge of the protective film.

In the radiation detector, the peripheral edge of the scintillator layer may have a tapered shape in which the height gradually decreases toward the outside of the scintillator layer. By setting the height of the peripheral edge of the scintillator layer to be lower toward the outside in this way, it is possible to limit the region where the adverse effect of the laser beam extends to the scintillator layer during manufacturing.

In the radiation detector, the protective film may include a metal film that reflects light. As a result, it is possible to prevent the light generated in the scintillator layer from leaking to the outside, and it is possible to improve the detection sensitivity of the radiation detector.

The method for manufacturing a radiation detector according to the other aspect is a light receiving portion including a plurality of photoelectric conversion elements arranged in one or two dimensions, and a light receiving portion electrically connected to the photoelectric conversion element and arranged outside the light receiving portion. The process of preparing a photoelectric conversion element array having a plurality of bonding pads and laminating the scintillator layer for converting radiation into light on the photoelectric conversion element array so as to cover the light receiving portion, and the step of laminating the scintillator layer. In some cases, a step of forming a resin frame on the photoelectric conversion element array so as to be separated from the scintillator layer and the bonding pad, pass between the scintillator layer and the bonding pad, and surround the scintillator layer, and at least the photoelectric conversion element array. By forming a protective film so as to cover the entire surface on the side where the scintillator layer is laminated and irradiating laser light along the resin frame, the protective film is cut and the outer part of the protective film is removed. In the step of forming the resin frame, the first distance between the inner edge of the resin frame and the outer edge of the scintillator layer is the first distance between the outer edge of the resin frame and the outer edge of the photoelectric conversion element array. The resin frame is formed so as to be shorter than 2 distances.

According to the method for manufacturing a radiation detector according to the other aspect, since the protective film on the resin frame is cut by the laser beam, no skill is required as compared with cutting by a cutter, and the productivity is improved. be able to. Further, since the protective film can be cut with high accuracy by the laser beam, the resin frame can be miniaturized. Further, by forming the resin frame apart from the scintillator layer and the bonding pad, it is possible to suppress an adverse effect on the scintillator layer and the bonding pad due to the laser beam when cutting the protective film. On the other hand, by forming the resin frame close to the scintillator layer, the effective area of the scintillator layer can be increased.

According to the present invention, it is possible to provide a radiation detector in which both the miniaturization of the apparatus and the large effective area of the scintillator layer are achieved and the productivity is improved.

It is a top view of the radiation detector which concerns on one Embodiment of this invention. It is sectional drawing along the line II-II of FIG. It is an enlarged plan view near the corner of the radiation detector of FIG. It is sectional drawing which shows (a) the state before scintillator layer formation and (b) the state after scintillator layer formation in the manufacturing process of the radiation detector of FIG. It is sectional drawing which shows (a) the state after the resin frame formation and (b) the state after the first organic film formation in the manufacturing process of the radiation detector of FIG. It is sectional drawing which shows (a) the state after formation of an inorganic film and (b) the state after formation of a second organic film in the manufacturing process of the radiation detector of FIG. It is sectional drawing which shows the processing process by a laser beam in the manufacturing process of the radiation detector of FIG. It is sectional drawing which shows (a) the state after cutting a protective film and (b) the state after forming a coating resin layer in the manufacturing process of the radiation detector of FIG.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings. When possible, the same parts are designated by the same reference numerals and duplicate description is omitted. Moreover, the dimensions and shapes in each drawing are not necessarily the same as the actual ones.

First, the configuration of the radiation detector 1 according to the present embodiment will be described with reference to FIGS. 1 and 2. As shown in FIGS. 1 and 2, the radiation detector 1 includes a photoelectric conversion element array 7, a scintillator layer 8, a resin frame 9, a protective film 13, and a coating resin layer 14. The photoelectric conversion element array 7 has a substrate 2, a light receiving unit 3, a signal line 4, a bonding pad 5, and a passivation film 6. The protective film 13 has a first organic film 10, an inorganic film (metal film) 11, and a second organic film 12.

The light receiving unit 3 is configured to include a plurality of photoelectric conversion elements 3a arranged two-dimensionally in a rectangular region at the center of an insulating substrate 2 (for example, a glass substrate). The photoelectric conversion element 3a is composed of an amorphous silicon photodiode (PD), a thin film transistor (TFT), and the like. Each of the photoelectric conversion elements 3a in each row or column in the light receiving unit 3 is electrically connected to a bonding pad 5 for extracting a signal to an external circuit (not shown) by a signal line 4 for reading a signal.

A plurality of bonding pads 5 are arranged at predetermined intervals along two adjacent sides (upper side and right side in FIG. 1) of the outer edge of the substrate 2, and a plurality of corresponding photoelectric conversion elements 3a are arranged via a signal line 4. Is electrically connected to. An insulating passivation film 6 is formed on the photoelectric conversion element 3a and the signal line 4. For the passivation film 6, for example, silicon nitride, silicon oxide, or the like can be used. The bonding pad 5 is exposed for connection with an external circuit.

A columnar scintillator 8a that converts X-rays (radiation) into light is laminated on the photoelectric conversion element array 7 so as to cover the light receiving portion 3. The scintillator layer 8 is formed by stacking a plurality of scintillators 8a in a substantially rectangular region (region surrounded by a broken line in FIG. 1) including a light receiving portion 3 in the photoelectric conversion element array 7. Various materials can be used for the scintillator 8a, and for example, Tl-doped CsI having good luminous efficiency can be used.

The peripheral edge portion 8b of the scintillator layer 8 has a tapered shape in which the height gradually decreases toward the outside of the scintillator layer 8. That is, the height of the peripheral portion 8b is lower than that of the scintillator 8a formed on the outer side of the scintillator layer 8. Here, the peripheral edge portion 8b is a region in which the light receiving portion 3 is not formed below (a region outside the effective screen), or a region having a small influence on X-ray image generation. Therefore, by providing the peripheral edge portion 8b having such a tapered shape, it is possible to limit the region on the scintillator layer 8 that is adversely affected by the laser beam during manufacturing. Here, the gradient angle of the peripheral edge portion 8b, that is, the angle θ formed by a straight line connecting the height positions of the scintillator 8a formed on the peripheral edge portion 8b from the inside to the outside of the scintillator layer 8 with respect to the upper surface of the substrate 2. , 20 to 80 degrees.

The resin frame 9 is formed on the photoelectric conversion element array 7 so as to pass between the scintillator layer 8 and the bonding pad 5 and surround the scintillator layer 8 when viewed from the stacking direction A of the scintillator layer 8. There is. The shape of the corners of the resin frame 9 is an arc shape (so-called R shape) that is convex outward. The resin frame 9 is, for example, a silicone resin.

The resin frame 9 is formed so that the central portion is higher than both edge portions, and the height d1 of the resin frame 9 is lower than the height d of the scintillator layer 8. As a result, the resin frame 9 can be downsized, and the adverse effect of the laser beam during manufacturing on the scintillator layer 8 can be suppressed. Here, the height d1 of the resin frame 9 is the distance between the upper surface position of the photoelectric conversion element array 7 and the apex position of the resin frame 9, and the height d of the scintillator layer 8 is included in the scintillator layer 8. This is the maximum height of the scintillator 8a.

The resin frame 9 is preferably made as small as possible from the viewpoint of downsizing the radiation detector 1. More specifically, the height d1 of the resin frame 9 is preferably 450 μm or less, and the width d2 of the resin frame 9 is preferably 900 μm or less. Here, the width d2 of the resin frame 9 is the width between the inner edge E1 (edge portion on the scintillator layer 8 side) of the resin frame 9 and the outer edge E2 (edge portion on the bonding pad 5 side) of the resin frame 9.

Further, the distance (first distance) D1 between the inner edge E1 of the resin frame 9 and the outer edge E3 of the scintillator layer 8 is the distance (first distance) between the outer edge E2 of the resin frame 9 and the outer edge E4 of the photoelectric conversion element array 7. 2 distance) It is shorter than D2. The ratio of the second distance D2 to the first distance D1 is 5 or more from the viewpoint of suppressing the adverse effect of the laser beam during manufacturing on the bonding pad 5 and securing the effective area of the scintillator layer 8. Is preferable. More specifically, the first distance D1 is preferably 1 mm or less, and the second distance D2 is preferably 5 mm or more. This is due to the following reasons.

The effective area of the scintillator layer 8 can be maximized if there is no gap between the outer edge E3 of the scintillator layer 8 and the inner edge E1 of the resin frame 9. However, considering the adverse effect of the laser beam during manufacturing on the scintillator layer 8 and the slight failure in the process of forming the resin frame 9 (for example, the resin frame 9 is formed on the scintillator layer 8). , It is preferable to secure the first distance D1 in the range of 1 mm or less. Further, by setting the second distance D2 to 5 mm or more, a sufficient distance can be secured between the resin frame 9 and the bonding pad 5 in consideration of the adverse effect of the laser beam during manufacturing on the bonding pad 5.

The scintillator layer 8 is covered with a protective film 13. The protective film 13 is formed by laminating the first organic film 10, the inorganic film 11, and the second organic film 12 from the scintillator layer 8 side in this order. The first organic film 10, the inorganic film 11, and the second organic film 12 all have the property of transmitting X-rays (radiation) and blocking water vapor. Specifically, a polyparaxylylene resin, polyparachloroxylylene, or the like can be used for the first organic film 10 and the second organic film 12. Further, the inorganic film 11 may be transparent, opaque or reflective with respect to light, and the inorganic film 11 may be an oxide film such as Si, Ti or Cr, gold, silver or aluminum (for example). A metal film such as Al) can be used. By using a metal film that reflects light as the inorganic film 11, it is possible to prevent the fluorescence generated by the scintillator 8a from leaking to the outside, and it is possible to improve the detection sensitivity of the radiation detector 1. In this embodiment, an example in which Al, which is easy to mold, is used as the inorganic film 11 will be described. Al itself is easily corroded in the air, but the inorganic film 11 is protected from corrosion because it is sandwiched between the first organic film 10 and the second organic film 12.

The protective film 13 is formed by, for example, a CVD method. Therefore, in the state immediately after the protective film 13 is formed, the protective film 13 is formed so as to cover the entire surface of the photoelectric conversion element array 7. Therefore, in order to expose the bonding pad 5, the protective film 13 is cut at a position inside the bonding pad 5 of the photoelectric conversion element array 7, and the outer protective film 13 is removed. As will be described later, the protective film 13 is cut (processed) by laser light near the central portion of the resin frame 9, and the outer edge 13a of the protective film 13 is fixed by the resin frame 9. This makes it possible to prevent the protective film 13 from peeling off from the outer edge 13a. Here, for cutting the protective film 13, for example, a carbon dioxide gas laser (CO ₂ laser), an ultrashort pulse (nanosecond or picosecond) semiconductor laser or the like can be used. By using a carbon dioxide gas laser, the protective film 13 can be cut in one scanning (short time), and the productivity is improved. The adverse effect on the photoelectric conversion element array 7, the bonding pad 5, the scintillator layer 8, and the like is thermal damage when, for example, a carbon dioxide gas laser or an ultrashort pulse laser is used.

The outer edge 13a of the protective film 13 is located on the resin frame 9, and is coated together with the resin frame 9 by a coating resin layer 14 arranged along the resin frame 9. For the coating resin layer 14, a resin having good adhesiveness to the protective film 13 and the resin frame 9, such as an acrylic adhesive, can be used. The same silicone resin as the resin frame 9 may be used for the coating resin layer 14. Alternatively, the same acrylic adhesive as the coating resin layer 14 may be used for the resin frame 9.

Next, the corners (corners) of the resin frame 9 and the protective film 13 will be described with reference to FIG. In FIG. 3, the coating resin layer 14 is partially omitted so that the states of the corners of the resin frame 9 and the protective film 13 can be easily understood.

As will be described in detail later, in the manufacturing process of the radiation detector 1, the laser beam is applied to the protective film 13 on the resin frame 9, so that the portion of the protective film 13 irradiated with the laser beam is cut and removed. .. Here, since the protective film 13 is very thin, a part of the resin frame 9 is also cut and removed by the laser beam of the carbon dioxide gas laser. As a result, a groove portion (corresponding region) 9a is formed near the center of the resin frame 9. The outer edge 13a of the protective film 13 and the groove portion 9a corresponding to the outer edge 13a of the protective film 13 in the resin frame 9 are in a state of being processed by laser light. Here, the depth (height) d3 of the groove portion 9a is set to 1/3 or less of the height d1 of the resin frame 9. As a result, the adverse effect of the laser beam on the photoelectric conversion element array 7 located below the resin frame 9 is suppressed.

As shown in FIG. 3, the outer edge 13a and the groove portion 9a of the protective film 13 processed by the laser beam have an arcuate corner portion that is convex outward when viewed from the stacking direction A of the scintillator layer 8 (in FIG. 3). It is formed in a substantially rectangular ring shape having the region B) shown. Further, the outer edge 13a and the groove portion 9a of the protective film 13 have a fine wavy shape when viewed from the stacking direction A. That is, the surfaces of the outer edge 13a and the groove 9a of the protective film 13 have a minute uneven shape, unlike a flat cut surface by a cutting tool such as a cutter. As a result, the contact area between the outer edge 13a and the groove 9a of the protective film 13 and the coating resin layer 14 increases, so that the adhesion between the outer edge 13a and the groove 9a of the protective film 13 and the coating resin layer 14 can be further strengthened. ..

Next, a method for manufacturing the radiation detector 1 according to the present embodiment will be described with reference to FIGS. 4 to 8. First, as shown in FIG. 4A, the photoelectric conversion element array 7 is prepared. Subsequently, as shown in FIG. 4B, in the region on the photoelectric conversion element array 7 covering the light receiving portion 3, a Tl-doped columnar crystal of CsI is grown to a thickness of about 600 μm by, for example, a vapor deposition method. As a result, the scintillator layer 8 is formed (laminated).

Further, as shown in FIG. 5A, the resin frame 9 is formed on the photoelectric conversion element array 7. Specifically, the resin frame 9 is formed so as to pass between the scintillator layer 8 and the bonding pad 5 and surround the scintillator layer 8 when viewed from the stacking direction A of the scintillator layer 8. More specifically, the resin frame 9 is formed at a position where the first distance D1 is 1 mm or less and the second distance D2 is 5 mm or more. For the formation of the resin frame 9, for example, an automatic XY coating device can be used. Hereinafter, for convenience of description, a scintillator layer 8 and a resin frame 9 formed on the photoelectric conversion element array 7 are referred to simply as a “board”.

CsI forming the scintillator layer 8 has high hygroscopicity, and if it is left exposed, it absorbs water vapor in the air and dissolves. Therefore, for example, by the CVD method, the surface of the entire substrate is covered with polyparaxylylene having a thickness of 5 to 25 μm. As a result, the first organic film 10 is formed as shown in FIG. 5 (b).

Subsequently, as shown in FIG. 6A, 0 is formed on the surface of the first organic film 10 on the incident surface (the surface on which the scintillator layer 8 of the radiation detector 1 is formed) on which radiation is incident. An inorganic film (metal film) 11 is formed by laminating an Al film having a thickness of .2 μm by a vapor deposition method. Subsequently, the surface of the entire substrate on which the inorganic film 11 is formed is again coated with polyparaxylylene having a thickness of 5 to 25 μm by the CVD method. As a result, the second organic film 12 is formed as shown in FIG. 6 (b). The second organic film 12 has a role of preventing deterioration of the inorganic film 11 due to corrosion. By the above treatment, the protective film 13 is formed. The portion of the protective film 13 outside the substantially central portion of the resin frame 9 (the portion covering the bonding pad 5) is removed by the subsequent treatment. Therefore, the first organic film 10 and the second organic film 12 are formed on the side surface of the photoelectric conversion element array 7 and the surface opposite to the side on which the scintillator layer 8 of the photoelectric conversion element array 7 is laminated. It doesn't have to be.

Subsequently, as shown in FIG. 7, the laser beam L is irradiated along the resin frame 9 to cut the protective film 13. Specifically, the laser light L is moved by moving the laser light head (not shown) that irradiates the laser light L with respect to a stage (not shown) on which the entire substrate having the protective film 13 formed on the surface is placed. Is scanned along the resin frame 9 in a one-stroke manner. More specifically, the laser beam L is scanned along a substantially central portion (the thickest portion) of the resin frame 9. As a result, the adverse effect of the laser beam on the photoelectric conversion element array 7 below the resin frame 9 can be suppressed.

Here, in the vicinity of the corner portion of the resin frame 9, it is necessary to reduce the scanning speed in order to switch the scanning direction of the laser beam L. At the position on the resin frame 9 where the scanning speed is reduced, the irradiation amount of the laser beam is increased, so that the depth of the groove portion 9a is increased. As a result, there is a problem that the adverse effect of the laser beam on the photoelectric conversion element array 7 below the resin frame 9 becomes large. However, in the present embodiment, as shown in FIG. 3, the laser beam L is scanned so that the outer edge 13a and the groove portion 9a of the protective film 13 have an arc shape (so-called R shape) convex outward at the corner portion. Therefore, the deceleration of the scanning speed of the laser beam L at the corner portion can be reduced, or the corner portion can be processed without decelerating the scanning speed of the laser beam L. As a result, it is possible to suppress the adverse effect of the laser beam on the photoelectric conversion element array 7 below the resin frame 9 near the corners of the resin frame 9.

When the laser beam L is scanned along the resin frame 9 in a one-stroke manner, the laser irradiation is performed twice at the start position and the end position of the laser irradiation. Therefore, the depth of the groove portion 9a of the resin frame 9 becomes large, which may have a serious adverse effect on the photoelectric conversion element array 7 below the resin frame 9. However, in the present embodiment, the irradiation position and irradiation intensity of the laser beam L are such that the depth d3 of the groove portion 9a generated by one irradiation of the laser beam L is 1/3 or less of the height d1 of the resin frame 9. Etc. are controlled. As a result, even if the laser irradiation is performed twice at the same position, the depth of the groove portion 9a is not so large, and it is possible to prevent the photoelectric conversion element array 7 below the resin frame 9 from being seriously adversely affected. ..

Subsequently, as shown in FIG. 8A, the bonding pad 5 is exposed by removing the outer portion (including the portion opposite to the incident surface) from the cut portion of the protective film 13 by the laser beam L. Let me. Subsequently, as shown in FIG. 8B, a coating resin such as an ultraviolet curable acrylic resin is coated along the resin frame 9 so as to cover the outer edge 13a of the protective film 13 and the resin frame 9. Then, the coating resin is cured by irradiation with ultraviolet rays to form the coating resin layer 14.

Further, even if the coating resin layer 14 is not provided, the protective film 13 is in close contact with the photoelectric conversion element array 7 via the resin frame 9. However, by forming the coating resin layer 14, the protective film 13 including the first organic film 10 is sandwiched and fixed between the resin frame 9 and the coating resin layer 14, and is fixed on the photoelectric conversion element array 7. The adhesion of 13 is further improved. Therefore, since the scintillator 8a is sealed by the protective film 13, it is possible to reliably prevent the infiltration of water into the scintillator 8a, and it is possible to prevent the resolution of the element from being lowered due to the deterioration of moisture absorption of the scintillator 8a.

Next, the operation of the radiation detector 1 according to the present embodiment will be described with reference to FIGS. 1 and 2. X-rays (radiation) incident from the incident surface side pass through the protective film 13 and reach the scintillator 8a. This X-ray is absorbed by the scintillator 8a, and the scintillator 8a emits light proportional to the amount of X-ray light. Of the emitted light, the light that is retrograde to the incident direction of the X-ray is reflected by the inorganic film 11. Therefore, almost all the light generated by the scintillator 8a is incident on the photoelectric conversion element 3a via the passivation film 6. Each photoelectric conversion element 3a generates an electric signal corresponding to the amount of incident light by photoelectric conversion and accumulates it for a certain period of time. The amount of this light corresponds to the amount of incident X-rays. That is, the electric signal stored in each photoelectric conversion element 3a corresponds to the amount of incident X-rays. Therefore, this electric signal provides an image signal corresponding to the X-ray image. The image signal stored in the photoelectric conversion element 3a is sequentially read from the bonding pad 5 via the signal line 4 and transferred to the outside. The transferred image signal is processed by a predetermined processing circuit, so that an X-ray image is displayed.

In the radiation detector 1 described above, the protective film 13 on the resin frame 9 is cut (processed) by the laser beam. Since processing by laser light does not require skill as compared with cutting by a cutter, productivity can be improved. Further, according to the laser beam, the protective film 13 can be cut with higher accuracy than the case of manual operation, so that the resin frame 9 can be miniaturized. Further, since the resin frame 9 is formed so as to be separated from the scintillator layer 8 and the bonding pad 5, it is possible to suppress an adverse effect on the scintillator layer 8 and the bonding pad 5 due to laser light during manufacturing. On the other hand, by arranging the resin frame 9 as close as possible to the scintillator layer 8, the effective area of the scintillator layer 8 can be increased. Therefore, according to the radiation detector 1, it is possible to achieve both miniaturization of the device (radiation detection device including the radiation detector 1) and enlargement of the effective area of the scintillator layer 8 and improvement of productivity.

Further, according to the manufacturing method of the radiation detector 1 according to the present embodiment, since the protective film 13 on the resin frame 9 is cut by the laser beam, no skill is required as compared with cutting by a cutter. Productivity can be improved. Further, since the protective film 13 can be cut with high accuracy by the laser beam, the resin frame 9 can be miniaturized. Further, by forming the resin frame 9 apart from the scintillator layer 8 and the bonding pad 5, it is possible to suppress the adverse effect of the laser beam on the scintillator layer 8 and the bonding pad 5 when the protective film 13 is cut. On the other hand, by forming the resin frame 9 close to the scintillator layer 8, the effective area of the scintillator layer 8 can be increased.

The present invention has been described in detail above based on the embodiment. However, the present invention is not limited to the above embodiment. The present invention can be modified in various ways without departing from the gist thereof. For example, in the above description, the protective film 13 having a structure in which the inorganic film 11 is sandwiched between the organic films 10 and 12 made of polyparaxylylene has been described, but the first organic film 10 and the second organic film 10 have been described. The material of the film 12 may be different. Further, when a material resistant to corrosion is used as the inorganic film 11, the second organic film 12 itself may not be provided. Further, although a plurality of photoelectric conversion elements 3a are arranged two-dimensionally as the light receiving unit 3, the light receiving unit 3 may be one in which a plurality of photoelectric conversion elements 3a are arranged one-dimensionally. The bonding pad 5 may be formed on three sides of the rectangular radiation detector 1 instead of the two sides. In the above embodiment, the method of laser machining by moving the laser beam head has been described, but the resin frame 9 and the protective film 13 may be laser machined by moving the stage on which the radiation detector 1 is placed. Good.

1 ... radiation detector, 2 ... substrate, 3 ... light receiving part, 3a ... photoelectric conversion element, 4 ... signal line, 5 ... bonding pad, 6 ... passion film, 7 ... photoelectric conversion element array, 8 ... scintillator layer, 8a ... Scintillator, 8b ... peripheral edge, 9 ... resin frame, 9a ... groove (corresponding area), 10 ... first organic film, 11 ... inorganic film (metal film), 12 ... second organic film, 13 ... protective film, 13a ... outer edge of protective film 13, 14 ... coating resin layer, D1 ... first distance, D2 ... second distance, d, d1, d3 ... height, d2 ... width, E1 ... inner edge of resin frame 9, E2 ... resin The outer edge of the frame 9, E3 ... the outer edge of the scintillator layer 8, E4 ... the outer edge of the photoelectric conversion element array 7.

Claims (6)

A photoelectric conversion element array having a light receiving unit including a plurality of photoelectric conversion elements arranged one-dimensionally or two-dimensionally, and a plurality of bonding pads electrically connected to the photoelectric conversion element and arranged outside the light receiving unit. When,
A scintillator layer that is laminated on the photoelectric conversion element array so as to cover the light receiving portion and converts radiation into light,
When viewed from the stacking direction of the scintillator layer, the photoelectric conversion element array is separated from the scintillator layer and the bonding pad, passes between the scintillator layer and the bonding pad, and surrounds the scintillator layer. With the resin frame formed on the top
A protective film having an outer edge located on the resin frame, which covers the scintillator layer, is provided.
The outer edge of the protective film and the corresponding region of the resin frame corresponding to the outer edge of the protective film are in a state of being processed by laser light.
The peripheral edge of the scintillator layer has a tapered shape in which the height gradually decreases toward the outside of the scintillator layer.
A radiation detector in which the distance between the inner edge of the resin frame and the outer edge of the scintillator layer is 1 mm or less. With more boards
The photoelectric conversion element is provided on the upper surface of the substrate.
The radiation detector according to claim 1, wherein the angle formed by the straight line connecting the height positions of the peripheral portions of the scintillator layer and the upper surface of the substrate is in the range of 20 degrees to 80 degrees. The radiation detector according to claim 1 or 2, wherein the scintillator layer is formed by Tl-doped CsI. The radiation detector according to any one of claims 1 to 3, wherein the protective film includes a metal film that reflects light. The radiation detector according to any one of claims 1 to 4, further comprising a coating resin layer arranged along the resin frame so as to cover the outer edge of the protective film. The radiation detector according to any one of claims 1 to 5, wherein the protective film includes an organic film made of polyparaxylylene.

Images