RADIATION DETECTION SENSOR, RADIATION IMAGING APPARATUS AND MANUFACTURING METHOD

Abstract

To reduce malfunction due to soot generated during a step of peeling a flexible matrix panel.SOLUTION: A protective layer is formed on an exposed portion of an electrode formed when connecting a matrix panel to an integrated circuit before a peeling step in order to protect the exposed portion form soot generated during the peeling step.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a radiation imaging apparatus and a radiation imaging apparatus. [Background technology]

[0002] The manufacturing technology for display devices using thin film transistors (TFTs) is applied to matrix panels for large area sensors that have TFTs and semiconductor photoelectric conversion elements, and are used as radiation detection devices in combination with scintillators that convert radiation into light. This matrix panel was generally formed on a glass substrate, but in recent years, flexible matrix panels that use resins and other materials to reduce the weight of the device and are expected to be resistant to impacts and deformation have been developed, and are now being used in radiation detection devices.

[0003] A typical method for forming a flexible matrix panel is to place a thin flexible insulating layer made of a resin material or the like on a rigid substrate such as a glass substrate, form an area sensor on the flexible insulating layer, and then remove the substrate. For example, according to Patent Document 1, a flexible insulating layer is first formed on a substrate such as glass, and then a matrix panel is formed on the flexible insulating layer. After connecting a readout circuit and a drive circuit to the matrix panel via a wiring member such as a flexible printed circuit board (FPC), the substrate is peeled off by irradiating it with a laser beam. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5142943 Summary of the Invention [Problem to be solved by the invention]

[0005] In the peeling process, when the flexible insulating layer is irradiated with strong light such as laser light, a part of the flexible insulating layer undergoes ablation (evaporation due to light heating). At this time, the expansion of the generated gas causes peeling at the interface between the substrate and the flexible insulating layer, and at the same time, conductive foreign matter (soot) is generated on the surface of the flexible insulating layer.

[0006] Normally, FPCs have exposed electrode sections, so if soot adheres across the exposed sections of multiple different electrodes, it can cause a short circuit between the FPC wiring. This can cause a poor connection with the drive circuit, resulting in malfunction of the matrix panel. It can also cause a poor connection with the readout circuit, resulting in a reading error that causes a problem with reading signals from the matrix panel. Soot can be removed (cleaned) using various methods, but cleaning can actually scatter soot, which can cause the above-mentioned defects.

[0007] The present invention provides a manufacturing method capable of reducing short circuits between FPC wirings caused by soot in a radiation imaging device using a flexible matrix panel, and a radiation imaging device in which short circuits between FPC wirings caused by soot are unlikely to occur. [Means for solving the problem]

[0008] A method for manufacturing a radiation detection sensor includes the steps of supporting a second surface of a flexible circuit board, on a light-transmitting base material, the second surface having a plurality of pixels arranged in a two-dimensional matrix, connecting a wiring member to a conductive portion electrically connected to any one of the plurality of pixels, the conductive portion being provided at an end of the first surface of the circuit board, and before The wiring components Conductive The method is characterized by including the steps of forming a protective layer to cover the exposed portion, irradiating the second surface with light that transmits through the base material, and peeling the circuit board from the base material. Effect of the Invention

[0009] According to the present invention, it is possible to reduce operational failures caused by soot in a radiation imaging device using a flexible matrix panel. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a plan view showing an integrated circuit connected to a flexible radiation detection panel according to a first embodiment; [Diagram 2] FIG. 1 is a structural diagram of an FPC 20 used in a read wiring member 32 and a drive wiring member 42 in the first embodiment. [Diagram 3] FIG. 2 is an enlarged plan view of a portion A in FIG. 1 according to the first embodiment; [Figure 4] FIG. 1 is a process block diagram showing an example of a method for manufacturing a radiation detection panel according to a first embodiment. [Diagram 5] FIG. 5 is a cross-sectional view of the radiation detection panel in step (a) of FIG. 4 according to the first embodiment. [Figure 6] FIG. 5 is a cross-sectional view of the radiation detection panel in step (b) of FIG. 4 according to the first embodiment. [Figure 7] 5 is a cross-sectional view of the radiation detection panel in step (c) of FIG. 4 according to the first embodiment. [Figure 8] 5 is a cross-sectional view of the radiation detection panel in step (d) of FIG. 4 according to the first embodiment; [Figure 9] 5 is a cross-sectional view of the radiation detection panel in step (e) of FIG. 4 according to the first embodiment. [Figure 10] 5 is a cross-sectional view of the radiation detection panel in step (f) of FIG. 4 according to the first embodiment. [Figure 11] 10A and 10B are cross-sectional views of a radiation detection panel illustrating a protective layer forming step and a peeling step according to a second embodiment; [Figure 12] 1 is a cross-sectional view of a radiation imaging device using a radiation detection panel according to a second embodiment. [Figure 13] 13 is a cross-sectional view of the radiation detection panel and the wiring member, illustrating a wiring member mounting process according to the third embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (First embodiment) FIG. 1 is a plan view showing a flexible radiation detection panel according to the present embodiment to which an integrated circuit is connected.

[0012] Two types of integrated circuits (a readout circuit 31 and a drive circuit 41) mounted on a circuit board are connected to the radiation detection panel 10. The readout circuit 31 is a circuit for reading out electrical signals from a plurality of pixels 15 provided on a matrix panel 11 of the radiation detection panel 10, and is connected to a readout device 30 via a readout wiring member 32. The drive circuit 41 is a circuit for supplying drive signals to the plurality of pixels 15, and is connected to the drive device 40 via a drive wiring member 42.

[0013] In this embodiment, these two types of wiring members, namely the readout wiring member 32 and the drive wiring member 42, are configured with FPCs. From the viewpoint of space-saving wiring, FPCs are suitable for these wiring members, but flexible flat cables (FFCs) and the like may also be used, and the form is not important as long as it can electrically connect the radiation detection panel 10 and the integrated circuit.

[0014] Note that an enlarged plan view of part A surrounded by a dashed line in the figure is shown in FIG. 3, and details will be described later in the description of FIG.

[0015] 2(a) and (b) are structural diagrams of an FPC 20 that can be used for the readout wiring member 32 and the drive wiring member 42. The FPC 20 is made of a base material 21, conductive parts 22, and a conductive part coating layer 23. The base material 21 and the conductive part coating layer 23 are made of an organic insulating material such as polyimide. A plurality of conductive parts 22 made of a conductor such as copper are disposed extending toward an integrated circuit (not shown) (readout circuit 31 or drive circuit 41) mounted on the FPC 20, and connect the pixels in the radiation detection panel 10 to the integrated circuit. The B-B' portion in the figure will be described later in the explanation of FIGS. 5 to 10.

[0016] The number of conductive portions 22 is set to three here for ease of explanation, but may be increased to 250, 500, or more depending on the configuration. Most of the conductive portions 22 are covered with a conductive portion covering layer 23, but there are portions near the ends where the conductive portion covering layer 23 is not provided and the conductive portions 22 are exposed in order to electrically connect with the matrix panel 11. Hereinafter, the portions where the conductive portions 22 are exposed are referred to as exposed portions 29.

[0017] Fig. 3 is an enlarged plan view of portion A in Fig. 1. The flexible radiation detection panel 10 has a matrix panel 11 and a scintillator 12, both of which are flexible. The matrix panel 11 has a plurality of pixels 15 formed in a two-dimensional matrix on a flexible insulating layer, which will be described later. Each pixel 15 has a switching element 16 and a conversion element 17.

[0018] In this embodiment, the switch element 16 and the conversion element 17 are respectively an amorphous silicon thin film transistor (a-Si TFT) and an MIS type photoelectric conversion element. The switch element 16 and the conversion element 17 are not limited to the above combination, and known techniques such as polysilicon TFT, oxide TFT, and PIN type photoelectric conversion element can be used.

[0019] The matrix panel 11 further has a plurality of gate lines 19 extending in the row direction, a plurality of signal lines 18 extending in the column direction, and bias lines 14 for supplying bias voltages to each conversion element 17. The scintillator 12 converts radiation such as X-rays into visible light. As the scintillator 12, gadolinium oxysulfide (GOS) mixed with a binder, or cesium iodide (CsI) using thallium (Tl) or sodium (Na) as an activator can be used.

[0020] Furthermore, a scintillator moisture-proof layer 13 may be formed to protect the scintillator 12 from humidity in the environment. As the scintillator moisture-proof layer 13, it is possible to use metals such as aluminum, copper, and stainless steel, resins such as polyparaxylylene, epoxy resin, acrylic resin, and polyester resin, and composite materials made of resin and ceramics such as alumina and titanium oxide.

[0021] The scintillator moisture-proof layer may be formed of a conductor such as a metal and connected to a predetermined potential to provide protection (electromagnetic shielding) from electromagnetic radiation noise. In addition, in order to obtain flatness and impact resistance during the formation of the scintillator, the planarization layer 25 may be formed of an organic insulating layer such as polyimide.

[0022] The signal lines 18 are electrically connected to the read connection parts 34 provided on the matrix panel 11. Meanwhile, the read wiring member 32 mounted on the matrix panel 11 has conductive parts 22 arranged opposite to the read connection parts 34. Each conductive part 22 is electrically connected to the read connection part 34 via a conductive adhesive 24 made of an anisotropic conductive film (ACF) or the like.

[0023] Similarly, each of the multiple gate lines 19 is electrically connected to a multiple number of drive connection parts 44. The drive wiring member 42 mounted on the matrix panel 11 has conductive parts 22 arranged to face each of the drive connection parts 44. Each conductive part 22 is electrically connected to the drive connection part 44 via a conductive adhesive 24. In this way, each pixel 15 is electrically connected to the readout circuit 31 and the drive circuit 41.

[0024] Fig. 4 is a process block diagram showing an example of a method for producing a radiation detection panel 10. Figs. 5 to 10 are cross-sectional views of the radiation detection panel 10 corresponding to each of the steps (a) to (f) in Fig. 4, taken along the line B-B' in Fig. 2. Using these, an example of a method for producing a radiation detection panel will be described in detail.

[0025] (a) Pixel formation process 5 is a cross-sectional view of the radiation detection panel 10 in a pixel formation process. A flexible insulating layer 101 made of a polymer material such as polyimide is formed on a substrate 100 such as glass.

[0026] Flexible insulating layer 101 may be formed, for example, by applying a polyimide solution to substrate 100 and baking it, or a polyimide film formed separately into a membrane may be attached to substrate 100. Note that the "first surface" of the "flexible insulating layer" in the present invention is the upper surface of flexible insulating layer 101 on which pixels 15 are formed in Fig. 5, and the "second surface" is the lower surface of flexible insulating layer 101 that is in contact with substrate 100 in Fig. 5.

[0027] Next, the switch element 16 is formed on the flexible insulating layer 101. The switch element 16 includes a gate electrode 162, a gate insulating layer 161, a first a-Si layer 165, a first n-type silicon layer 166, and a second n-type silicon layer 168 on the rear surface of the flexible insulating layer 101 opposite to the surface in contact with the substrate 100. + This is obtained by forming a -Si layer 166, a drain electrode 163, and a source electrode 164.

[0028] A first inorganic insulating layer 168 and an organic planarization layer 169 are formed in this order on the substrate. Further, a lower electrode 171, a sensor inorganic insulating layer 172, a second a-Si layer 173, a second n + The -Si layer 174, bias line 14, and upper electrode 175 are formed to obtain the conversion element 17. These are covered with a second inorganic insulating layer 179 to serve as a passivation layer. Finally, the second inorganic insulating layer 179, the sensor inorganic insulating layer 172, the first inorganic insulating layer 168, and the gate insulating layer 161 above the drive connection portion 44 are etched to provide an opening 180, and the matrix panel 11 is obtained.

[0029] (b) Scintillator and moisture-proof layer formation process 6 is a cross-sectional view of the radiation detection panel 10 in the process of forming a scintillator and a moisture-proof layer. A planarization layer 25 is formed of polyimide on the second inorganic insulating layer 179. Then, a CsI thin film is formed to a desired thickness on the planarization layer 25 by vacuum deposition to form the scintillator 12. A scintillator moisture-proof layer 13 made of a laminated composite material of aluminum and resin is attached to the scintillator 12 via an adhesive layer 131.

[0030] (c) Wiring component mounting process 7 is a cross-sectional view of the radiation detection panel 10 in the wiring member mounting step. A layer of conductive adhesive 24 is formed so as to fill the opening 180. The driving wiring member 42 and the readout wiring member 32 (not shown) are mounted on the matrix panel 11 so that the conductive portions 22 of the driving wiring member 42 and the readout wiring member 32 (not shown) are electrically connected to the driving connection portions 44 and the readout connection portions 34 on the matrix panel 11, respectively.

[0031] Most of the exposed portions 29 of the drive wiring members 42 and the readout wiring members 32 disappear because they are filled with the conductive adhesive 24, but some remain as shown in Fig. 7. If soot, which will be described later, adheres to or accumulates in these portions, it can cause malfunctions and reading errors in the matrix panel.

[0032] (d) Protective layer formation process 8 is a cross-sectional view of the radiation detection panel 10 in the protective layer forming step. In the exposed portion 29, a protective layer 50 is formed using an insulating member so as to cover the conductive portion 22. The formation method may be a known method such as coating, vapor deposition, or adhesion. The protective layer 50 may have any thickness or shape as long as it has the effect of preventing the adhesion and accumulation of soot, which will be described later. In addition, the protective layer does not have to be a continuous film, and may be, for example, a mottled coating such as polka dots. Specific examples of the protective layer will be described later.

[0033] (e) Peeling process 9 is a cross-sectional view of the radiation detection panel 10 in the peeling step. Light 60 is irradiated onto the flexible insulating layer 101 through the substrate 100 on the surface opposite to the surface on which the pixels 15 and the scintillator 12 are formed. The wavelength of the light 60 is preferably such that it is mostly transmitted through the substrate 100 and efficiently absorbed by the flexible insulating layer 101. The intensity of the light 60 (energy density, unit: mJ / cm2) is preferably equal to or greater than the ablation threshold of the flexible insulating layer 101.

[0034] When light 60 is incident with an intensity equal to or greater than the ablation threshold, a portion of flexible insulating layer 101 near the interface with substrate 100 is ablated, causing peeling from substrate 100. At the same time, another portion of flexible insulating layer 101 is carbonized, generating soot 70 at the interface with substrate 100. The ablation threshold of polyimide material is 150 to 170 mJ / cm2, but taking into consideration the temporal fluctuation of the laser output and the intensity distribution on the target object, it is preferable to set the intensity of light 60 to an intensity sufficiently greater than the ablation threshold.

[0035] On the other hand, if the strength is too high, the amount of soot generated will increase. When the substrate 100 is made of alkali-free glass (EagleXG (registered trademark), etc.) and the flexible insulating layer 101 is made of polyimide, an excimer laser or solid-state laser is used as the light source of the light 60 that satisfies the above conditions of wavelength and strength. For example, a third harmonic (355 nm) of an Nd:YAG laser, which is a type of solid-state laser, may be appropriately shaped into a beam and swept over the flexible insulating layer 101 while repeatedly irradiating it with pulses.

[0036] (f) Cleaning process Fig. 10 is a cross-sectional view of the radiation detection panel 10 in the cleaning process. After removing the substrate 100, the soot 70 generated on the entire lower surface of the flexible insulating layer 101 is removed. Various cleaning methods can be used, such as dry (suction with a vacuum cleaner, adhesion with adhesive tape, etc.) and wet (wiping with a solvent or immersion, etc.). As shown in Fig. 10, wiping with a cloth 72 impregnated with an organic solvent 71 such as isopropyl alcohol is particularly effective.

[0037] The protective layer 50 of this embodiment may be made of any of the following materials.

[0038] Antistatic agent: An antistatic agent made of a surfactant or the like is dispersed in a solvent such as water, sprayed or applied to the exposed portion 29, and dried to obtain the protective layer 50. The antistatic agent attracts water vapor in the ambient atmosphere, which has the effect of preventing the adhesion and accumulation of soot 70 due to static electricity. Since the antistatic agent is weakly wiped off, it is preferable to perform the cleaning process in a dry manner. In addition, since the protective layer made of the antistatic agent exhibits weak conductivity (surface resistance of 1012 Ω / sq or less), if this becomes a problem, a wet (wiping) cleaning process may be separately performed to remove the antistatic agent after removing the soot in the dry cleaning process. Alternatively, the antistatic agent may be sprayed or applied to the surface of the insulating member as the protective layer 50 and dried to provide the surface of the insulating member with an antistatic function.

[0039] Water-repellent treatment agent: A water-repellent treatment agent such as SF Coat (registered trademark, manufactured by AGC) or Toyal Lotus (registered trademark, manufactured by Toyo Aluminum) is sprayed or applied to exposed portion 29 and dried to obtain protective layer 50. These water-repellent treatment agents have the effect of lowering the surface energy of exposed portion 29 and preventing the adhesion and accumulation of soot 70.

[0040] Second embodiment Fig. 11(a) is a cross-sectional view of the radiation detection panel 10 showing the protective layer forming step in this embodiment, and corresponds to Fig. 8 of the first embodiment. The difference between this embodiment and the first embodiment is that the sealant 80 fulfills the function of the protective layer 50, and other configurations and steps are similar. The sealant 80 is formed so as to cover the exposed portion 29, and prevents the adhesion and accumulation of soot. The material of the sealant 80 may be any material that can prevent the adhesion and accumulation of soot, and examples of the material that can be used include silicone resin, epoxy resin, acrylic resin, etc. Also, as shown in the figure, a part of the sealant 80 may be in contact with the substrate 100.

[0041] 11(b) is a cross-sectional view of the radiation detection panel 10 showing the peeling step in this embodiment, which corresponds to Fig. 9 of the first embodiment. When a part of the sealing material 80 is formed so as to be in contact with the substrate 100 in the protective layer forming step, the lower surface of the contacting part (contact portion) 81 forms approximately the same plane as the lower surface of the flexible insulating layer 101. Note that the contact portion 81 may be partially ablated by the light 60, similar to the flexible insulating layer 101.

[0042] 12 is a cross-sectional view showing a part of a radiation imaging device using the radiation detection panel of this embodiment. A flexible insulating layer 101 and a driving device 40 are fixed to a support base 82 by an adhesive and screws, respectively. The support base 82 is fixed to an exterior 83 of the imaging device by screws. Meanwhile, the driving wiring member 42 is connected to the matrix panel 11 and the driving device 40 by a conductive adhesive 24 or the like, but other mechanical fixation is not required.

[0043] In this embodiment, in addition to the same effects as those of the first embodiment, the sealing material 80 protects the connection electrodes 33, 43 from foreign matter other than soot, dirt, moisture, and the like.

[0044] Furthermore, when a portion of the sealant 80 is formed to contact the substrate 100 in the protective layer formation process, the following effect can be obtained. That is, the sealant 80 is structured to be in surface contact with the support base 82 at the contact portion 81. Therefore, even if the exterior 83 is subjected to an impact from an external force, the impact applied to the drive wiring member 42 is dispersed and mitigated. For the readout wiring member 32, the sealant 80 can be formed in the same shape as above to obtain the same effect. That is, even if an impact from an external force is received, the electrical connection between the pixels and the external circuit is kept stable, improving the reliability of the radiation imaging device.

[0045] (Third embodiment) FIG. 13 is a cross-sectional view showing the wiring member mounting process of this embodiment, and corresponds to FIG. 7 and FIG. 8 of the first embodiment. The difference between this embodiment and the first embodiment is that the conductive adhesive 24 functions as the protective layer 50. Furthermore, the wiring member mounting process in this embodiment also serves as the protective layer formation process (FIG. 4(d) and FIG. 8). The other configurations and processes are the same as those of the first embodiment. The conductive adhesive 24 is formed so as to cover the exposed portion 29, and prevents the adhesion and accumulation of soot.

[0046] In this embodiment, since the conductive adhesive 24 also serves as the protective layer 50, the same effects as those of the first embodiment can be obtained simply and at low cost. [Explanation of symbols]

[0047] 10 Radiation Detection Panel 11 Matrix Panel 12 Scintillator 14 Bias wire 15 pixels 16 Switching element 17 Conversion element 18 Signal Line 19 Gate Line 20 Wiring materials 22 electrodes 23 Covering layer 24 Conductive adhesive 29 Exposed part 34 Read connection 44 Drive connection 60 light 70 Soot

Claims

1. A step of supporting a second surface of a flexible circuit board, on which a plurality of pixels are arranged in a two-dimensional matrix, on a light-transmitting base material; a step of connecting a wiring member to a conductive portion electrically connected to any one of the plurality of pixels, the conductive portion being provided at an end portion of the first surface of the circuit board; forming a protective layer that covers an exposed conductive portion of the wiring member in a state in which the conductive portion and the wiring member are connected; irradiating the second surface with light that transmits through the base material and peeling the circuit board from the base material; A method for manufacturing a radiation detection sensor comprising the steps of:

2. 2. The manufacturing method according to claim 1, further comprising a cleaning step, subsequent to said peeling step, for removing conductive foreign matter generated in said peeling step.

3. The manufacturing method according to claim 2 , further comprising the step of removing the protective layer after the cleaning step.

4. The manufacturing method according to claim 1 , further comprising the step of forming a scintillator on the first surface.

5. 5. A method for manufacturing a radiation imaging device according to claim 1, wherein an integrated circuit connected to the wiring member is at least one of a drive circuit for supplying drive signals to the plurality of pixels and a readout circuit for reading out electrical signals from the plurality of pixels.

6. The method according to claim 1 , wherein the protective layer is a layer formed of an antistatic agent.

7. The method according to claim 1 , wherein the protective layer is a layer formed from a water repellent treatment agent.

8. The manufacturing method according to claim 1 , wherein the protective layer is a layer formed of a sealing material.

9. The manufacturing method according to claim 1 , wherein the protective layer is a layer formed of an adhesive containing an anisotropic conductive film.

10. A flexible circuit board on which a plurality of pixels are arranged in a two-dimensional matrix, the circuit board including a conductive portion at an end of a first surface, the conductive portion being electrically connected to any one of the plurality of pixels; A wiring member connected to the conductive portion; an insulating protective member that covers an exposed conductive portion of the wiring member when the conductive portion and the wiring member are connected to each other, the protective member protecting the exposed portion from foreign matter that is generated when the second surface of the circuit board is peeled off from the light-transmitting base material by light irradiation; A radiation detection sensor comprising:

11. 11. The radiation imaging apparatus according to claim 10, wherein a scintillator is provided on the first surface.

12. 12. The radiation detection sensor according to claim 10, wherein the integrated circuit connected to the wiring member is at least one of a drive circuit for supplying drive signals to the plurality of pixels and a readout circuit for reading out signals from the plurality of pixels.

13. 11. The radiation detection sensor according to claim 10, wherein a surface of the protective member has an antistatic function.

14. 11. The radiation detection sensor according to claim 10, wherein the protective member has a water-repellent function.

15. The radiation detection sensor according to claim 10, wherein the protective member is a sealant.

16. 11. The radiation detection sensor according to claim 10, wherein the protective member is an adhesive containing an anisotropic conductive film.

17. A radiation imaging device comprising the radiation detection sensor according to claim 10 .

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