JP2000065941A - X-ray image detector and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the damage of an X-ray conversion layer and a switching element when an X-ray image detector is built in a device provided with a drive circuit or the like and to enhance the yield of the X-ray image detector. SOLUTION: A pair of substrates 1, 2 are pasted and constituted. An X-ray conversion layer 5 which generates an electric charge or light according to the intensity of X-rays at a time when the X-rays are irradiated is formed on the substrate 2 on one side out of them. Then, a collecting electrode 18 which fetches the electric charge generated in the X-ray conversion layer 5 or which fetches an electric charge according to a quantity of light generated in the X-ray conversion layer 5 and a switching element 3 which is connected to the collecting electrode 18 are formed on the substrate 1 on the other side. In addition, the collecting electrode 18 is formed on a flattening film 20 which is formed on the switching element 3 and which flattens the formation face of the switching element 3, and it is connected to the switching element 3 via a contact hole 20a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray image detector having a plurality of X-ray sensors arranged in a matrix, and a method for manufacturing the same.

[0002]

2. Description of the Related Art An X-ray image detector has been conventionally used as a medical diagnostic apparatus. X-ray image detectors include:
There are mainly two systems, a direct conversion system and an indirect conversion system. The direct conversion method is a method in which an X-ray is irradiated to an X-ray conversion layer to generate electric charges, and the electric charges are read out through a charge storage capacitor and a switching element connected to each charge storage capacitor. An X-ray image detector of the direct conversion system is described in, for example, JP-A-6-342098.

The indirect conversion system is a system in which an X-ray conversion layer is irradiated with X-rays to convert it into visible light, and the visible light is read out through a photodiode and a switching element connected to each photodiode. is there. An indirect conversion type X-ray image detector is described in, for example, JP-A-8-51195.

The construction of the direct conversion type X-ray image detector (X-ray image capturing element) described in Japanese Patent Application Laid-Open No. 6-342098 will be described below. FIG.
It is a schematic sectional drawing of the X-ray image detector described in the said publication. FIG. 11 shows a 1X-ray sensor portion corresponding to one pixel.

[0005] The X-ray image detector 116 is mounted on the glass substrate 11.
2 on the glass substrate 112, a capacitance electrode 118, a capacitance dielectric layer 119, a collecting electrode 1
04 and the charge blocking layer 110 are formed in this order.

The capacitance electrode 118 is made of metal, and the capacitance dielectric layer 119 is made of SiO ₂ , SiN _X or the like. The collecting electrode 104 is made of aluminum or ITO (Ind
iumTin Oxide). Also, the charge blocking layer 110
In the case where the collecting electrode 104 is formed from aluminum, the aluminum oxide layer formed on the surface of the collecting electrode 104 can be used as the charge blocking layer 110.

The capacitance electrode 118 and the collecting electrode 104 described above, and the capacitance dielectric layer 11 sandwiched therebetween
At 9, the charge storage capacitor 106 is configured. One charge storage capacitor 106 is used for an X-ray conversion layer 1 described later.
08 corresponds to one pixel of the minimum unit capable of resolving the image represented by the X-ray intensity distribution written in the X-ray conversion layer 1.
08 constitutes a 1X-ray sensor.

[0008] Such a charge storage capacitor 106 is
As shown in FIG. 12, a plurality of collecting electrodes 104 arranged on a glass substrate 112 and constituting each charge storage capacitor 106 are arranged on the glass substrate 112 in a matrix. FIG. 12 is an equivalent circuit diagram including the driving circuit of the X-ray image detector 116 shown in FIG.

The charge blocking layer 110 functions as a blocking diode by the collecting electrode 104 formed in the lower layer and the X-ray conversion layer 108 formed in the upper layer. It is forbidden to flow to.

On the other hand, on the glass substrate 112, FIG.
As shown in FIG. 1, a thin film transistor (hereinafter, referred to as a switching element) corresponding to each charge storage capacitor 106 is a switching element.
A TFT (Thin Film Transistor) 105 is formed.

Each TFT 105 includes a gate electrode 111a, a gate insulating film 120 covering the gate electrode 111a, an a-si layer 115, a source electrode 113a, and a drain electrode 114, which are stacked in this order from the glass substrate 112 side.

Source electrode 113 in each TFT 105
As shown in FIG. 12, a is connected between a plurality of collecting electrodes 104 provided in a matrix and any one of a plurality of source bus lines 113 running vertically in the figure. The gate electrode 111a of each TFT 105 is connected to one of the plurality of gate bus lines 111 running in the left-right direction in the drawing between the plurality of collecting electrodes 104. The source bus lines 113 and the gate bus lines 111 are arranged to be orthogonal to each other with the gate insulating film 120 interposed therebetween. The drain electrode 114 of each TFT 105 is connected to the plurality of collecting electrodes 10.
4 is connected.

Each TFT 105 is turned on when a bias voltage is applied to the gate electrode 111 a via the gate bus line 111, and conducts between the source bus line 113 and the charge storage capacitor 106.

Further, as shown in FIG.
5 is covered with a passivation layer 121, and the charge storage capacitor 106 is also covered with the passivation layer 121.

Further, an X-ray conversion layer 108 is formed on the glass substrate 112 so as to cover the TFTs 105, the charge storage capacitors 106, the gate bus lines 111, and the source bus lines 113. On the line conversion layer 108, a dielectric layer 117 and a front conductive layer 109 made of a conductive material that transmits X-ray radiation are sequentially formed.

The X-ray conversion layer 108 preferably has a high dark resistance, and is composed of amorphous selenium, lead oxide, cadmium sulfide, mercuric iodide, and other similar substances.

The above-mentioned capacitance electrode 118, capacitance dielectric layer 119, collecting electrode 104, charge blocking layer 11
0, the X-ray conversion layer 108, the dielectric layer 117, and the front conductive layer 109 are continuously formed on the glass substrate 112.

As shown in FIG. 12, a switch 132 for switching each gate bus line 111 between a first position A and a second position B is connected to the end of each gate bus line 111 described above. Have been.

When the switches 132 are in the first position A, the bias voltage for turning on the TFTs 105 is simultaneously applied to all the gate bus lines 111 via the line 133 while the switches 32 are turned on. When in the second position B, each gate bus line 111 is driven independently, and a bias voltage is applied at a different timing via the line 135. The switches 132 are simultaneously switched by a signal input from the line 137.

At the end of each source bus line 113, a charge amplification detector 136 is connected. Each charge amplification detector 136 can be comprised of an operational amplifier and is wired to measure charge in a capacitance circuit that generates a voltage output proportional to the charge output from charge storage capacitor 106. By sequentially sampling the detection output of each charge amplification detector 136, an output signal including information obtained by each X-ray sensor can be obtained.

Further, each of the above-mentioned capacitance circuits includes a panel section of the X-ray image detector 116 and a gate bus line 111.
. And the source bus lines 113. In addition, as shown in FIG.
09 and a plurality of connection electrodes for electrically connecting the front conductive layer 109 and the plurality of capacitance electrodes 118 to a power supply 127 that supplies a series of programmable variable voltages by accessing the plurality of capacitance electrodes 118. Have been.

[0022]

However, in the structure of the conventional X-ray image detector described above, the X-ray conversion layer 10 is formed on the same substrate on which the TFT and the charge storage capacitor are formed.
8, a dielectric layer 117 and a front conductive layer 109 are formed.

For example, if the X-ray conversion layer 108 is damaged when the X-ray conversion layer 108 is formed, the TFT
Although there is no problem with the 105 and the charge storage capacitor 106, the substrate itself, that is, the X-ray image detector itself cannot be used, thereby lowering the yield.

Further, a TFT 105 and a charge storage capacitor 106 are formed, and an X-ray conversion layer 10 is further formed thereon.
8, the process of forming the dielectric layer 117 and the front conductive layer 109 is long, and if it becomes impossible to use it after such a long process, the cost becomes extremely low.

The X-ray conversion layer 10 is formed on the same substrate on which the TFT 105 and the charge storage capacitor 106 are formed.
In the configuration in which the dielectric layer 117 and the front conductive layer 109 are formed, the front conductive layer 109 is exposed. Therefore, even if the front conductive layer 109 is completed without any problem, the X-ray image detector 116 is thereafter driven by the driving circuit. When the device is incorporated into a device body having the above-described structure, the front conductive layer 109 or even the X-ray conversion layer 108 below the front conductive layer 109 is damaged, which results in a reduction in yield.

The present invention has been made in view of such problems, and has as its object to provide a configuration of an X-ray image detector which can be obtained at a high yield and a method of manufacturing the same.

[0027]

According to a first aspect of the present invention, there is provided an X-ray image detector according to the first aspect of the present invention. An X-ray conversion layer for generating light, a plurality of collecting electrodes arranged in a matrix and taking in charges generated in the X-ray conversion layer or charges corresponding to the amount of generated light, and a plurality of collecting electrodes. An X-ray image detector including a switching element provided, wherein the X-ray conversion layer, a plurality of collecting electrodes, and a plurality of switching elements are sandwiched between a pair of substrates.

According to this, since the switching element and the X-ray conversion layer are sandwiched between the pair of substrates, the conventional X-ray conversion layer is formed.
The switching element and the X-ray conversion layer are not damaged when the X-ray image detector is incorporated into another device having a drive circuit or the like, unlike the configuration in which the X-ray conversion layer is exposed.

According to another aspect of the present invention, there is provided an X-ray image detector for generating an electric charge or light according to the intensity of the X-ray when irradiated with the X-ray. A conversion layer, a plurality of collecting electrodes arranged in a matrix and taking in charges generated in the X-ray conversion layer, or charges corresponding to the generated light amount, and switching elements provided for each collecting electrode. In the X-ray image detector having the above, a pair of substrates are bonded to each other, the X-ray conversion layer is formed on one of the substrates, and the plurality of collecting electrodes and the plurality of switching elements are formed on the other substrate. Are formed, and these collecting electrodes are formed on a flattening film for flattening a switching element formation surface formed on each switching element. It is a symptom.

According to a seventh aspect of the present invention, there is provided a method of manufacturing an X-ray image detector according to the first aspect of the present invention. And a plurality of collecting electrodes arranged in a matrix and taking in charges generated in the X-ray conversion layer or charges corresponding to the amount of generated light, and provided for each collecting electrode. In the method for manufacturing an X-ray image detector having a switching element,
Forming a plurality of the switching elements, a flattening film for flattening a switching element formation surface formed on each switching element, and a plurality of the collecting electrodes disposed on the flattening film; A step of forming the X-ray conversion layer on a substrate different from the substrate;
A third method of bonding the first substrate obtained in the first step and the second substrate obtained in the second step with the collecting electrode formation surface and the X-ray conversion layer formation surface facing each other. And a process.

According to the configuration of the second and seventh aspects, the switching element and the X-ray conversion layer are sandwiched between the pair of substrates, as in the configuration of the first aspect. The switching element and the X-ray conversion layer are not damaged when the X-ray image detector is incorporated in another device having a drive circuit or the like, as in the configuration disclosed.

In addition, since the switching element formation surface is flattened by the flattening film, the switching element is not damaged when it is bonded to the substrate on which the X-ray conversion layer is formed.

When a defect is present in the switching element or the X-ray conversion layer, the X-ray image detector itself formed in a long process in the conventional method becomes defective. Since the layers and the switching elements are formed on separate substrates, the steps of forming the substrate on which the X-ray conversion layer is formed and the substrate on which the switching elements are formed are short and have defects. In this case, it is only necessary to use only the substrate having the defect, so that the X-ray image detector itself does not become defective.

According to a third aspect of the present invention, in the X-ray image detector according to the second aspect, the flattening film is made of an organic material.

It is desirable that the collecting electrode formed above the flattening film is formed as large as possible in order to improve the sensitivity. In this case, the collecting electrode is used to drive the above-described switching element, for example, a source bus line or a gate bus. The structure overlaps with the line.
Therefore, the parasitic capacitance of the collecting electrode is minimized,
In order to achieve flatness, the flattening film desirably has a small relative dielectric constant of 3.5 or less, and an organic material is suitable.

Further, the flattening film needs to be formed to be somewhat thick for the purpose of eliminating the step on the surface on which the switching element is formed, but the organic material also has an advantage that it can be easily formed into a thick film by spin coating.

According to a fourth aspect of the present invention, there is provided an X-ray image detector according to the third aspect, wherein the thickness of the flattening film is 2.5 to 10 μm.

According to this, while the parasitic capacitance of the collecting electrode is minimized by using an organic material, the step on the surface on which the switching element is formed can be surely eliminated and flattened.

According to a fifth aspect of the present invention, in the X-ray image detector according to the first, second, third or fourth aspect, the X-ray conversion layer is separated corresponding to the collecting electrode. It is characterized by.

According to a method of manufacturing an X-ray image detector according to an eighth aspect of the present invention, in the configuration according to the seventh aspect, in the second step, the X-ray conversion layer is separated corresponding to the collecting electrode. It is characterized by including a step.

According to the fifth and eighth aspects of the present invention, since the X-ray conversion layer is formed separately according to the shape of the collecting electrode, no horizontal leakage current occurs between adjacent collecting electrodes. Thus, it is possible to avoid a decrease in resolution.

According to a sixth aspect of the present invention, there is provided an X-ray image detector according to the first, second, third, fourth or fifth aspect.
The substrate on which the X-ray conversion layer is formed also has a function as an X-ray conversion layer.

According to this, since the X-ray conversion layer, which is deeply related to the quality of the X-ray image detector, is made of a hard substrate, the possibility of damage to the X-ray conversion layer can be further reduced, and the yield can be further improved. I can do it.

According to a ninth aspect of the present invention, there is provided a method of manufacturing an X-ray image detector according to the seventh or eighth aspect, wherein an anisotropic conductive material is used in the third step. .

According to this, since the first substrate and the second substrate are bonded using an anisotropic conductive material, the first and second substrates can be easily applied to a large-sized X-ray image detector. These two sheets can be bonded together.

[0046]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] The following will describe one embodiment of the present invention with reference to FIGS.

The X-ray image detector according to the present embodiment is a direct conversion type X-ray image detector having a charge storage capacitor. FIG. 2 is a plan view of the 1X-ray sensor portion of the X-ray image detector according to the present embodiment. FIG. 1 is a cross-sectional view of FIG.
FIG. 3 is a sectional view taken along line Y ′. However, in FIG. 2, for the sake of simplicity, the thin film above the charge blocking layer denoted by reference numeral 21 in FIG. 1, the gate insulating film 11a, and the capacitance dielectric layer 11b are not shown.

This X-ray image detector has the following features.
In addition to the substrate 1 on which the switching element 3 is formed, a substrate 2 is also provided on the outer surface side of the X-ray conversion layer 5, and the switching element 3 and the charge storage capacitor are provided between the pair of insulating substrates 1 and 2. 4, a structure in which the charge blocking layer 21, the X-ray conversion layer 5, the dielectric layer 6, and the front conductive layer 7 are sandwiched.

Here, for convenience of explanation, only the 1X-ray sensor portion will be described. However, the charge storage capacitor 4 and the switching element 3 are, as described in the above-mentioned prior art,
A plurality of gate bus lines 10 and source bus lines 13, which will be described later, are also provided so as to cross each other.

As the switching element 3, a thin film transistor (hereinafter, referred to as TFT) is employed. T
The FT 3 has a configuration in which a gate electrode 10a, a gate insulating film 11a, a semiconductor layer 12, a source electrode 13a, and a drain electrode 14a are stacked on the substrate 1 in this order.

The gate electrode 10a is, as shown in FIG.
The gate bus line 10 branches, and when a bias voltage is applied from the gate bus line 10, the TFT 3 is turned off.
N to make the source electrode 13a and the drain electrode 14a conductive. The source electrode 13a is connected to the source bus line 1
3, and outputs the charge flowing from the drain electrode 14a to a charge detector (not shown) of the drive circuit. The drain electrode 14a is connected to the upper capacitance electrode 14b of the charge storage capacitor 4.

As shown in FIG. 1, the charge storage capacitor 4 includes a lower capacitance electrode 15 and a capacitance dielectric layer 1 on a substrate 1.
1b, upper capacitor electrode 14b, and upper capacitor electrode 14b
Has a structure in which collecting electrodes 18 connected to are sequentially stacked.

Here, the collecting electrode 18 is formed on the flattening film 20 formed on the upper capacitor electrode 14b, and the contact hole 20 formed in the flattening film 20 is formed.
a. The flattening film 20 is made of TFT3
By providing the flattening film 20, a step (difference in height) due to a structural difference (such as the number of stacked films) between the charge storage capacitor 4 and the TFT 3 is eliminated, and charge storage is performed. The heights of the capacitor 4 and the TFT 3 can be made equal.

By providing such a flattening film 20, as shown in FIG.
Can be formed large by overlapping with the source bus line 13 and the gate bus line 10. This allows
The area of the X-ray conversion layer 5 corresponding to the collecting electrode 18 increases, the amount of charge generated in the X-ray conversion layer 5 and taken in by the collecting electrode 18 increases, and the sensitivity of the X-ray image detector improves. I can do it.

Hereinafter, the manufacturing process of the X-ray image detector will be described with reference to schematic cross-sectional views in each process shown in FIGS.

The manufacturing process of the X-ray image detector is roughly divided into a first substrate forming process of forming a TFT 3 and a charge storage capacitor 4 on a substrate 1, and a dielectric layer 6 and an X-ray
It comprises three steps: a second substrate forming step of forming the line conversion layer 5, and a substrate bonding step of bonding the first and second substrates.

In the first substrate forming step, first, as shown in FIG. 3 (a), Al, Ta or the like is deposited on an insulating substrate 1 made of glass or the like by sputtering for about 5 minutes.
By forming a film with a thickness of 00 nm and patterning the film by etching or the like, the gate bus line 10, the gate electrode 10a, and the lower capacitor electrode 15 parallel to the gate bus line 10 are formed (see FIG. 2).

Next, the gate bus line 10, gate electrodes 10a, and to cover the substrate 1 upper surface is formed to the lower capacitor electrode 15, Al ₂ O _3, CVD of SiO _2, SiN _X or the like (Chemical Vapor Deposi
The gate insulating film 11a and the capacitance dielectric layer 11b are formed by forming a film having a thickness of about 300 nm by the T.I. Subsequently, a semiconductor layer 12 is formed by depositing a-Si, p-Si, or the like with a thickness of about 100 nm by a CVD method and patterning the film by etching or the like. Also,
For the ohmic contact, n ⁺ a-Si is formed in a thickness of about 40 nm by a CVD method at a connection portion between the drain electrode 14a and the semiconductor layer 12, and is patterned.

Next, a film of Al, Ta, or the like is formed to a thickness of about 600 nm by sputtering or the like, and is patterned by etching or the like, so that the source bus line 1 is formed.
3. A source electrode 13a, a drain electrode 14a, and an upper capacitance electrode 14b are formed.

When the source bus line 13, the source electrode 13a, the drain electrode 14a, and the upper capacitor electrode 14b are formed in this manner, as shown in FIG. A film having a thickness of 2.5 to 10 μm is formed by a spin coating method using a resin material such as polyimide, and a flattening film 20 for eliminating a step of the TFT 3 is formed. Thereafter, exposure and development are performed to form a contact hole 20a in the flattening film 20.

A collecting electrode 18 is formed on the flattening film 20. The collecting electrode 18
Is desirably formed as large as possible in order to improve the sensitivity. In this case, the collecting electrode 18 has a structure overlapping with the source bus line 13 and the gate bus line 10. Therefore, in order to minimize the parasitic capacitance of the collecting electrode 18 and realize flatness,
The flattening film 20 preferably has a small relative dielectric constant of 3.5 or less, and has a thickness of about 2.5 μm to about 10 μm.

Thereafter, as shown in FIG. 3 (c), A1 or ITO is deposited for about 200 n using a sputtering method or the like.
m, and is patterned so as to overlap the gate bus line 10 and the source bus line 13 to form a collecting electrode 18 (see FIG. 2). Is created.

In the second substrate forming step, first, as shown in FIG.
O is deposited to a thickness of about 300 nm using a sputtering method or the like to form the front conductive layer 7, and then, for example, a polyethylene terephthalate film of about 20 μm is attached thereon to form the dielectric layer 6. Form.

Subsequently, Se is deposited thereon to a thickness of about 300 to 500 μm by a CVD method to form an X-ray conversion layer 5, and then Al ₂ O ₃ or the like is further deposited to a thickness of about 20 nm by the CVD method. And a charge blocking layer 21 is formed.

Thereafter, the dielectric layer 6, the X-ray conversion layer 5, and the charge blocking layer 21 in the region 22 where the collecting electrode 18 does not exist when the second substrate B is bonded to the first substrate A are etched or the like. Using the technique described in Thus, the second substrate B is created.

The first substrate A and the second substrate B thus produced are bonded in a substrate bonding step. In the substrate bonding step, as shown in FIG.
A sealing material (not shown) is arranged around the substrate A or the second substrate B, and the TFT 3 and the charge storage capacitor 4 are formed using alignment marks (not shown) provided on the respective substrates. On the formed first substrate A, X
The second substrate B is bonded with the side having the line conversion layer 5 facing each other. Thus, the X-ray image detector is completed.

Here, since the surface of the first substrate A facing the second substrate B is flattened by the flattening film 20, both bonding surfaces are flat, and the TFT 3 is damaged at the time of bonding. I do not receive it.

The X-ray image detector thus obtained detects electric charges by using a conventional driving circuit similar to that shown in FIG. 12, for example, and outputs the electric charges to the X-ray conversion layer 5 by X-rays. The written image can be read.

As described above, the X-ray image detector of the present embodiment has a configuration in which the TFT 3, the charge storage capacitor 4, the X-ray conversion layer 5, and the like are sandwiched between the pair of substrates 1 and 2. , When incorporating the X-ray image detector into the device body
3. The front conductive layer 7 and the X-ray conversion layer 5 are hardly damaged.

Moreover, the level difference between the TFT 3 and the charge storage capacitor 4 is eliminated by the flattening film 20, and the bonding surfaces of both the first substrate A and the second substrate B are flattened. When the substrate A is bonded to the second substrate B, the TFT 3 is not damaged.

If it is found that the TFT 3 or the X-ray conversion layer 5 has a defect, the conventional X-ray image detector formed in a long process may have a defect in the conventional configuration formed on the same substrate. However, in the case of a configuration having a pair of substrates 1 and 2 as in the X-ray image detector according to the present embodiment, the first substrate A and the second substrate B, which are separately formed, are attached. X-ray image detector can be obtained by combining
Each of the first substrate A and the second substrate B has a short manufacturing process,
In addition, since it is not necessary to use only the substrate side on which a defect exists, it is possible to improve the yield rate.

In the above configuration, since the X-ray conversion layer 5 is formed separately according to the shape of the collecting electrode 18, no horizontal leakage current occurs between the adjacent collecting electrodes 18. There is no danger of resolution degradation.

[Embodiment 2] Another embodiment of the present invention will be described below with reference to FIG. For convenience of explanation, members having the same functions as the members shown in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 6, the X-ray image detector according to the present embodiment is a direct conversion type X-ray image detector provided with a charge storage capacitor 4, and FIG. It has substantially the same configuration as the X-ray image detector of the first embodiment. The difference is that the first substrate A and the second substrate B
Are bonded together via an anisotropic conductive adhesive 33 disposed on the entire surface.

The anisotropic conductive adhesive 33 is, for example, a material in which conductive particles 33b are dispersed in an insulating adhesive 33a, and is a kind of anisotropic conductive material having conductivity only in the vertical direction. .

The X-ray image detector having the above-described structure is the same as that of the second
A second substrate B ′ having a configuration in which a protruding connection electrode 23 is further formed on the charge blocking layer 21 of the substrate B of FIG.
Is bonded to the first substrate A using the anisotropic conductive adhesive 33. The connection electrode 23 is made of, for example, Cr,
It is made of Al, ITO or the like.

Here, since the connection electrode 23 is protruded, pressure is concentrated on the connection electrode 23 during bonding, and the pressure required for bonding can be reduced. Further, the excess adhesive 33a can escape from the gap 24 between the connection electrodes 23, and a highly reliable connection structure can be obtained.

The bonding using an anisotropic conductive material such as the anisotropic conductive adhesive 33 is performed, for example, when the first and second substrates A and B ′ to be bonded are large-screen substrates. And the like, and the substrates can be easily bonded to each other.

[Embodiment 3] Another embodiment according to the present invention will be described below with reference to FIG. For convenience of explanation, members having the same functions as the members shown in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 7, the X-ray image detector of the present embodiment is a direct conversion type X-ray image detector having a charge storage capacitor 4, and FIG. 1 shows a schematic sectional structure thereof. It has substantially the same configuration as the X-ray image detector of the first embodiment. 1 is that the X-ray conversion layer 5 is formed on the substrate 2 in the second substrate B in the configuration of FIG. 1, but the substrate 25 made of a compound semiconductor material such as CdTe or CdZnTe is used here. The difference is that a second substrate B ″ having the function of the X-ray conversion layer is provided on the substrate 25 itself.

According to this configuration, although the front conductive layer 7 and the capacitive dielectric layer 6 are exposed on the outer surface of the substrate 25, the X-ray conversion layer is made of the hard substrate 25, so that the X-ray conversion layer is damaged. Possibilities can be further reduced.

As described in the second embodiment, the bonding of the second substrate B ″ and the first substrate A is performed by providing the connection electrode 23 and applying the anisotropic conductive adhesive 33. (See FIG. 6).

[Embodiment 4] An embodiment according to the present invention will be described below with reference to FIGS. For convenience of explanation, members having the same functions as the members shown in the above embodiment are denoted by the same reference numerals,
The description is omitted.

In the X-ray image detector of the first embodiment, selenium is used for the X-ray
Is a direct conversion type X-ray image detector that reads out the generated charges through the TFTs 3 in the present embodiment, but in the present embodiment, the X-rays are irradiated on, for example, CsI of the X-ray conversion layer to generate light. For example, P-type a-Si, non-dove a-
An indirect conversion type X-ray image detector that reads out electric charges from the TFT 3 via a photodiode composed of Si, n-type a-Si will be described.

FIG. 9 is a plan view of the 1X sensor portion of the X-ray image detector according to the present embodiment, and FIG.
FIG. However, in FIG. 9, for simplicity, the thin film above the photodiode indicated by reference numeral 31 in FIG. 8 and the gate insulating film 11 a are not shown.

As shown in FIG. 8, this X-ray image detector also has a feature that, in addition to the substrate 1 on which the switching element 3 is formed, the substrate 2 is provided on the outer surface side of the X-ray conversion layer 26 as well. Between the pair of insulating substrates 1 and 2
This is a structure in which T3, photodiode 31, and X-ray conversion layer 26 are sandwiched.

The first substrate A ′ on which the TFT 3 is formed is
The cross-sectional shape is almost the same as the first substrate A in the first embodiment shown in FIG. However, the lower capacitance electrode 15 formed in the first embodiment is not necessary in the present embodiment. Here, the shape of the drain electrode 14a is the same as the shape integrally formed even with the upper capacitor electrode 14b shown in the first embodiment. However, since it is not necessary to form a capacitor here, the shape of the drain electrode 14a is not necessarily required. It is not necessary to form as shown in FIG.

The second substrate C has an X-ray conversion layer 26 made of CsI, a transparent conductive film 27 made of ITO,
Type a-Si layer 28, non-dove a-Si layer 29, n-type a
-Photodiodes 31 composed of Si layers 30 are sequentially formed.

In this case as well, the P-type a-Si layer 2 in the region 32 of the first substrate A ′ where the collecting electrode 18 is not provided is provided.
8. The non-dove a-Si layer 29 and the n-type a-Si layer 30 were removed. Thereby, the light generated in the X-ray conversion layer 26 is not irradiated to the adjacent collecting electrode 18 to generate a leak current, and the resolution is not reduced.

An example of a method of forming the three layers constituting the photodiode 31 is as follows. The P-type a-Si layer 28 is formed by CVD.
Non-dove a-Si with a thickness of, for example, 50 nm by the method
The layer 29 has a thickness of, for example, 300 nm by the CVD method, and the n-type a-Si layer 30 has a thickness of, for example, 50 nm by the CVD method.
m.

As shown in FIG. 10, the first and second substrates A ′ and C are also similar to the X-ray image detector of the first embodiment, as shown in FIG. 2 is carried out via a sealing material (not shown) arranged in the peripheral portion on the side of the substrate C, but also in this case, the surfaces of the respective substrates are flat and can be bonded without damaging the TFT 3. .

Also, in the case of the X-ray image detector according to the present embodiment, similarly to the above-described second embodiment, the first bonded image detector is used.
And when the second substrates A ′ and C are large-screen substrates,
When the anisotropic conductive material is disposed on the entire surface of the substrate and the substrates are bonded to each other, the substrates can be easily bonded to each other.

The X-ray image detector thus obtained detects charges using a conventional driving circuit similar to that shown in FIG. 12, for example, and converts the X-rays into an X-ray conversion layer. The image written in 26 can be read.

As described above, in the X-ray image detector of the present embodiment, the TFT 3, the collecting electrode 18, the photodiode 31, the X-ray conversion layer 26 and the like are sandwiched between the pair of substrates 1 and 2. With this configuration, the TFT 3 and the X-ray conversion layer 5 are less likely to be damaged when the X-ray image detector is incorporated in the apparatus main body.

Further, the level difference between the TFT 3 and the collecting electrode 18 is eliminated by the flattening film 20, and the bonding surfaces of the first substrate A 'and the second substrate C are flattened. When the substrate A ′ is bonded to the second substrate C, the TFT 3 is not damaged.

If it is found that the TFT 3 or the X-ray conversion layer 26 has a defect, the X-ray image detector itself formed in a long process may have a defect in the conventional configuration which is formed on the same substrate. However, in the case of a configuration having a pair of substrates 1 and 2 as in the X-ray image detector of the present embodiment, the first substrate A ′ and the second substrate C, which are separately formed, are separated. Since the X-ray image detector can be obtained by laminating, the production steps of the first substrate A 'and the second substrate C are short, and it is not necessary to use only the side of the substrate where a defect exists. The rate can be improved.

Further, as in the conventional case, the TFT is formed on the same substrate.
And a collecting electrode, a photodiode, a transparent conductive film, and an X-ray conversion layer, a photodiode is formed and a transparent conductive film is formed thereon. Cutting will occur. Therefore, in order to solve this, a film for eliminating the step is formed between the photodiodes. However, when these are formed on the second substrate C side as described above, the transparent conductive film 27 is formed. Since it can be formed before the photodiode 31, there is no fear of step disconnection, and there is no need to form a film that absorbs steps.

[0098]

As described above, the X-ray image detector according to the first aspect of the present invention provides an X-ray conversion layer that generates charges or light according to the intensity of X-rays when irradiated with X-rays. And electric charges arranged in a matrix and generated in the X-ray conversion layer,
Alternatively, in an X-ray image detector having a plurality of collecting electrodes for taking in charges corresponding to the generated light amount and a switching element provided for each collecting electrode, the X-ray conversion layer, a plurality of collecting electrodes, And a plurality of switching elements are sandwiched between a pair of substrates.

As a result, when the X-ray image detector is incorporated in another device having a drive circuit or the like, the switching element and the X-ray conversion layer are damaged as in the conventional configuration in which the X-ray conversion layer side is exposed. Not receive.

As a result, there is an effect that the production yield of the device having the X-ray image detector can be improved.

As described above, the X-ray image detector according to the second aspect of the present invention comprises an X-ray conversion layer that generates charges or light according to the intensity of X-rays when irradiated with X-rays. Charges arranged in a matrix and generated in the X-ray conversion layer,
Alternatively, in an X-ray image detector having a plurality of collecting electrodes for taking in charges corresponding to the amount of generated light and a switching element provided for each collecting electrode, a pair of substrates is attached to one another, The X-ray conversion layer is formed on the substrate of
The plurality of collecting electrodes and the plurality of switching elements are formed, and these collecting electrodes are formed on a flattening film for flattening a switching element formation surface formed on each switching element. Configuration.

Further, according to the method of manufacturing an X-ray image detector according to claim 7 of the present invention, as described above, X-rays are irradiated with X-rays to generate charges or light corresponding to the intensity of the X-rays. A line conversion layer, a plurality of collecting electrodes arranged in a matrix and taking in charges generated in the X-ray conversion layer, or charges corresponding to the generated light amount, and switching elements provided for each collecting electrode A method of manufacturing an X-ray image detector having: a plurality of switching elements on a substrate; a planarization film for planarizing a switching element formation surface formed on each switching element; A first step of forming the plurality of collecting electrodes disposed on the substrate; a second step of forming the X-ray conversion layer on a substrate different from the substrate; and a first step of forming the X-ray conversion layer. First substrate obtained A second substrate obtained in the second step, a configuration and a third step of bonding to face the collecting electrode formation face and the X-ray conversion layer forming surface.

Thus, when the X-ray image detector is incorporated in another device having a drive circuit or the like, the switching element and the X-ray conversion layer are prevented from being damaged, and the X-ray conversion layer is formed by the flattening film. Damage to the switching element when bonding to the substrate on which it is formed can be avoided.

Further, since the X-ray conversion layer and the switching element are formed on different substrates, if there is a defect, it is only necessary to use only the substrate having the defect.
The substrate on which the line conversion layer is formed and the substrate on which the switching element is formed also have a short manufacturing process, and even if they cannot be used, the time loss is smaller than that of a substrate that has undergone a long manufacturing process.

As a result, there is an effect that the production yield of the device having the X-ray image detector can be improved.

An X-ray image detector according to a third aspect of the present invention is the X-ray image detector according to the second aspect, wherein the flattening film is made of an organic material.

Thus, the parasitic capacitance of the collecting electrode can be easily minimized while the collecting electrode has a structure overlapping the source bus line and the gate bus line. In addition, a thick film can be easily formed by spin coating.

As a result, it is possible to easily realize the X-ray image detector according to the second aspect, and to obtain an effect that the sensitivity can be increased.

An X-ray image detector according to a fourth aspect of the present invention is the X-ray image detector according to the third aspect, wherein the thickness of the flattening film is 2.5 to 10 μm.

As a result, the parasitic capacitance of the collecting electrode can be minimized by using an organic material, and the step on the surface on which the switching element is formed can be surely eliminated and flattened.

As a result, the X-ray image detector according to the second aspect can be more easily realized and the sensitivity can be increased.

An X-ray image detector according to a fifth aspect of the present invention is the X-ray image detector according to the first, second, third or fourth aspect, wherein the X-ray conversion layer is separated corresponding to a collecting electrode. It is.

According to a seventh aspect of the present invention, in the method of manufacturing an X-ray image detector according to the seventh aspect, in the second step, the X-ray conversion layer corresponds to a collecting electrode. This is a configuration that includes a separating step.

As a result, a leak current in the horizontal direction does not occur between adjacent collecting electrodes, so that a reduction in resolution can be avoided.

As a result, in addition to the effects of the first, second, third, or fourth aspect, there is an effect that the resolution can be improved.

An X-ray image detector according to claim 6 of the present invention is the X-ray image detector according to claim 1, 2, 3, 4 or 5.
The substrate on which the X-ray conversion layer is formed also has a function as an X-ray conversion layer.

As a result, claims 1, 2, 3, 4 or 5
In addition to the effects of the described configuration, there is an effect that the possibility that the X-ray conversion layer is damaged can be further reduced, and the yield can be further improved.

According to a ninth aspect of the present invention, there is provided a method of manufacturing an X-ray image detector according to the seventh or eighth aspect, wherein an anisotropic conductive material is used in the third step. .

As a result, even in a large-sized X-ray image detector having a large first and second substrate, these two substrates can be easily bonded to each other.
Even if the X-ray image detector having the same configuration as that of No. 5 is large, it is possible to manufacture the X-ray image detector with high yield without any problem.

[Brief description of the drawings]

FIG. 1, showing an embodiment of the present invention, is a schematic cross-sectional view illustrating a configuration of a 1X sensor portion of an X-ray image detector.

FIG. 2 is a plan view of the X-ray image detector shown in FIG.

3 (a) to 3 (c) are schematic cross-sectional views showing manufacturing steps of the X-ray image detector shown in FIG.

FIG. 4 is a schematic sectional view showing a manufacturing process of the X-ray image detector shown in FIG.

FIG. 5 is a schematic sectional view showing a manufacturing process of the X-ray image detector shown in FIG.

FIG. 6 shows another embodiment of the present invention, and is a schematic cross-sectional view illustrating a configuration of a 1X sensor portion of an X-ray image detector.

FIG. 7 shows still another embodiment of the present invention.
It is a schematic sectional drawing which shows the structure of the 1X sensor part of an X-ray image detector.

FIG. 8 shows still another embodiment of the present invention.
It is a schematic sectional drawing which shows the structure of the 1X sensor part of an X-ray image detector.

FIG. 9 is a plan view of the X-ray image detector shown in FIG.

FIG. 10 is a schematic sectional view showing a manufacturing process of the X-ray image detector shown in FIG.

FIG. 11 is a schematic sectional view of a conventional X-ray image detector.

FIG. 12 is an equivalent circuit diagram of the X-ray image detector shown in FIG.

[Explanation of symbols]

1, 2 Substrate 3 Switching element 4 Charge storage capacitor 5, 26 X-ray conversion layer 18 Collecting electrode 20 Flattening film 25 Substrate (substrate also serving as X-ray conversion layer) 33 Anisotropic conductive adhesive (anisotropic conductive material) A, A 'first substrate B, B', B ", C second substrate

Claims (9)

[Claims] An X-ray conversion layer that generates electric charges or light according to the intensity of X-rays when irradiated with X-rays, and an electric charge generated in the X-ray conversion layer, which is arranged in a matrix. In an X-ray image detector having a plurality of collecting electrodes for taking in charges corresponding to the generated light amount and a switching element provided for each collecting electrode, the X-ray conversion layer, the plurality of collecting electrodes, An X-ray image detector comprising a plurality of switching elements sandwiched between a pair of substrates. 2. An X-ray conversion layer that generates charges or light according to the intensity of X-rays when irradiated with X-rays, and an electric charge generated in the X-ray conversion layer, which is arranged in a matrix. In an X-ray image detector having a plurality of collecting electrodes for taking in electric charges corresponding to the generated light amount and a switching element provided for each collecting electrode, a pair of substrates is bonded, and one of the substrates is bonded. The X-ray conversion layer is formed on a substrate, and the plurality of collecting electrodes and the plurality of switching elements are formed on the other substrate, and these collecting electrodes are formed on each switching element. An X-ray image detector formed on a flattening film for flattening a formed switching element formation surface. 3. The X-ray image detector according to claim 2, wherein said flattening film is an organic material. 4. The X-ray image detector according to claim 3, wherein the thickness of the flattening film is 2.5 to 10 μm. 5. The method according to claim 1, wherein said X-ray conversion layer is separated corresponding to a collecting electrode.
5. The X-ray image detector according to 3 or 4. 6. The X-ray image detection according to claim 1, wherein the substrate on which the X-ray conversion layer is formed has a function as an X-ray conversion layer. vessel. 7. An X-ray conversion layer that generates charges or light according to the intensity of X-rays when irradiated with X-rays, and charges generated in the X-ray conversion layer, which are arranged in a matrix. In a method of manufacturing an X-ray image detector having a plurality of collecting electrodes for taking in charges corresponding to the generated light amount, and a switching element provided for each collecting electrode, the method comprises the steps of: A first step of forming a flattening film for flattening a switching element formation surface formed on each switching element, and the plurality of collecting electrodes disposed on the flattening film; Collects the second step of forming the X-ray conversion layer on another substrate, and collecting the first substrate obtained in the first step and the second substrate obtained in the second step. X-ray and the surface where the toning electrode is formed The third step in the method of manufacturing the X-ray image detector, characterized in that it comprises a bonding the 換層 forming surface to face. 8. The method for manufacturing an X-ray image detector according to claim 7, wherein the second step includes a step of separating the X-ray conversion layer in correspondence with the collecting electrode. 9. The method for manufacturing an X-ray image detector according to claim 7, wherein an anisotropic conductive material is used in said third step.