JPH11274524A - X-ray image pick up device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of point defect and line defect in a detected image, by arranging a first thin film transistor and a second thin film transistor parallel with the respective channel directions. SOLUTION: Metal on a substrate forms a gate electrode 17 of a thin film transistor(TFT), scanning lines, an auxiliary electrode 11, and a gate of a TFT for a protective diode. On the upper layer of the metal, a gate insulating film 23 is formed. On the upper layer of the film 23, picture element electrodes 3 are formed in picture elements excepting TFTs 1 for reading and protective diodes 5. As to the TFTs 1 for reading and the protective diodes 5, on the upper layer of the insulating film 23, a-Si 27, SiNX 29 for etching stopper and N<+> a-Si 31 are formed, and thereon a source 23 and a drain 34 as electrodes are formed of another metal, which forms a signal wire 7, a pad for leading-out, a voltage feeding line, and a source 37 and a drain 39 of a TFT for a protective diode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an X-ray imaging apparatus for a medical X-ray diagnostic apparatus.

[0002]

2. Description of the Related Art In recent years, the medical field has been moving toward a database of patient medical data for the purpose of prompt and accurate treatment. This is because patients generally use a plurality of medical institutions, and in such a case, there is a possibility that accurate medical treatment cannot be performed without data from other medical institutions. For example, there is concern about side effects with drugs administered at other medical institutions. It is necessary to take appropriate treatment in consideration of drugs administered at other medical institutions.

[0003] There is also a demand for the creation of a database for X-ray image data, and digitization of X-ray images is desired. Conventionally, a medical X-ray diagnostic apparatus uses a silver halide film for imaging, but in order to digitize the image, it is necessary to develop the photographed film and scan it again with a scanner or the like, which is troublesome and time consuming. It was hanging. Recently, a method of directly digitizing an image using a CCD camera of about 1 inch has been realized. However, for example, when taking an image of a lung, an optical device for condensing light is needed to image a region of about 40 cm × 40 cm, and the size of the device has become a problem.

An X-ray imaging apparatus using an a-Si TFT (amorphous silicon thin film transistor) has been proposed as a method for solving these two problems (for example, U.S. Pat.
S46889487: Hereinafter, an X-ray flat panel detector. ). The configuration of this X-ray flat panel detector is shown in FIG. 23, and the operation will be described below.

In FIG. 23, pixels e ₁ , ₁ are aS
It is composed of an iTFT 105, a photoelectric conversion film 101, and a pixel capacitance (hereinafter, referred to as Cst) 103, and the pixels e have an array shape (hereinafter, referred to as a TFT array) in which hundreds to thousands of pixels are arranged on each side in the vertical and horizontal directions. ing. A bias voltage is applied to the photoelectric conversion film 101 by a power supply 109. a-Si
The TFT 105 is connected to the signal line S1 and the scanning line G1, and is turned on and off by the scanning line driving circuit 113. The termination of the signal line S1 is
To the amplifier 115 for signal detection.

[0006] When light enters, a current flows through the photoelectric conversion film 101 and charges are accumulated in Cst 103. When the scanning lines are driven by the scanning line driving circuit 113 to turn on all the TFTs connected to one scanning line, the accumulated charges are transferred to the amplifier 115 through the signal line S1. The changeover switch 107 inputs the electric charge for each pixel to the amplifier 115 and converts it into a dot-sequential signal that can be displayed on a CRT or the like. The amount of charge varies depending on the amount of light incident on the pixel,
The output amplitude of amplifier 115 changes.

In the method shown in FIG. 23, a digital image can be directly obtained by A / D converting the output signal of the amplifier 115. Further, the pixel region in the figure has the same structure as a TFT-LCD (thin film transistor liquid crystal display) used in a notebook personal computer, and a thin and large screen can be easily manufactured.

The above description relates to an indirect conversion type X-ray flat panel detector in which incident X-rays are converted into visible light by a phosphor or the like, and the converted light is converted into electric charges by a photoelectric conversion film of each pixel. It is.

In addition, there is a direct conversion type X-ray flat panel detector which directly converts X-rays incident on a pixel into electric charges.

In this direct conversion type X-ray flat panel detector,
The magnitude of the bias applied to the X-ray (or light) charge conversion film is different from that of the indirect conversion method. In the case of the indirect conversion method, a negative bias of several volts is applied only to the photoelectric conversion film, and when light enters the photoelectric conversion film, each pixel has Cst provided in parallel with the photoelectric conversion film and the photoelectric conversion film itself. The electric charge is stored in the capacitance Csi. In this case, Cs
The voltage applied to t is the maximum number V of the bias applied to the photoelectric conversion film. On the other hand, in the direct conversion method,
The X-ray charge conversion film and Cst are connected in series, and a high bias of several kV is applied to them. Therefore, when an X-ray is incident on a pixel, the charge generated in the X-ray charge conversion film is accumulated in Cst. However, when the incident X-ray amount is excessive, the charge accumulated in Cst increases, and a voltage of several kV at maximum is applied. Is applied to Cst, and the TFT provided as a switch of the pixel and the insulation of Cst may be broken. Therefore, in the direct conversion method, it is necessary to take measures to prevent an excessive voltage from being applied to Cst. For example, in the prior art, FIGS. 24 and 25 of Example 1 (DenyL. Lee e)
tc. , SPIE, vol. 2432, pp237, 1
995), by further providing a dielectric layer (insulating layer) above the X-ray charge conversion film, three capacitors are arranged in series (dielectric layer: Cd, X-ray charge conversion film: Cse,
Cst), the charges generated in the X-ray charge conversion film are dispersed and accumulated to prevent the dielectric breakdown of the TFT, or as shown in FIG. 26 of Example 2 (Japanese Patent Application No. 8-161977). When excessive X-rays enter a pixel, charges generated as much as necessary are stored in Cst, and the remaining charges are diodes provided in each pixel (hereinafter referred to as protection diodes).
And discharges the light to the outside of the pixel to prevent dielectric breakdown of the TFT.

[0011]

In the first embodiment, since the metal layer divided for each pixel is not inserted between the X-ray charge conversion film: Cse and the dielectric layer: Cd, an image is captured once. It takes a long time to reset Cd from the camera, and there is a problem that a moving image cannot be taken.

On the other hand, in Example 2, since no capacitor is provided in series as in Example 1, no time is required for resetting, so that a fluoroscopic mode is possible. However, when a TFT is used as the protection diode, for example, if the potential of the terminal of the protection diode opposite to the pixel (hereinafter referred to as a drain) is 0 [V], that is, if the drain is connected to the pixel capacitance electrode, A small value (0 to 4 [V]) of a pixel potential (hereinafter referred to as a threshold voltage) at which electric charge starts to be released outside the pixel
In addition, there is a problem that the leakage current is large and cannot be used as a protection diode. This problem is solved by supplying a positive potential to the drain. But,
There is a problem that the noise of the signal is increased and the yield of the TFT array is reduced depending on how the power supply line for supplying the voltage is drawn. Further, as the number of TFTs used as a protection diode increases, the number of power supply lines increases, so that the decrease in the yield becomes remarkable.

At the same time, the ratio of the TFT and the power supply line to the pixel is large, and there is a problem that it is difficult to secure a pixel electrode which is an effective area as a sensor of one pixel and to obtain a capacity of the pixel.

The present invention has been made to solve such a problem, and an object of the present invention is to provide an X-ray imaging apparatus for a medical X-ray diagnostic apparatus incorporating means for solving the above-mentioned problem.

That is, in a direct conversion type X-ray flat panel detector, medical X-ray detectors are characterized in that the arrangement of a protection diode as a measure against a high voltage that can be applied to a readout TFT takes into account the routing of a power supply line. Provided is an X-ray imaging apparatus for a X-ray diagnostic apparatus.

More specifically, it is an object of the present invention to provide an image pickup apparatus which does not cause a short circuit or noise between a power supply line and another wiring, and can obtain a high yield.

In another conventional technique, three capacitors are arranged in series by further providing a dielectric layer (insulating layer) on the X-ray charge conversion film (dielectric layer: Cd, X-ray charge conversion film: Cse, Cst), the charge generated in the X-ray charge conversion film is dispersed and accumulated to prevent the dielectric breakdown of the TFT.

In this case, in order to form a new image, it is necessary to discharge the electric charge accumulated in the upper dielectric layer to a specified level. This method cannot respond to a moving image because it requires time for discharging and time for sampling an image.

On the other hand, when excessive X-rays enter a pixel, charges generated as much as necessary are stored in Cst, and the remaining charges are stored in a protection device (hereinafter, referred to as a protection device) provided in each pixel.
Protect device. ) Can be discharged outside the pixel to prevent the dielectric breakdown of the TFT.

When taking an image of a patient or the like, it is necessary to make the X-ray intensity as low as possible. In order to obtain a large dynamic range, it is preferable that a weak signal can be detected. The lower limit of such a weak signal is determined by the off-state current of the protection diode, the signal shift due to the stray capacitance, the noise of the operational amplifier, and the like. Changes in pixel potential due to current determine the lowest signal level that can be detected for small signals. In order to prevent this, it is necessary to reduce the value of the leak current and its fluctuation.

The present invention has been made to solve such a problem, and the leakage current of the protection TFT connected to the storage capacitor Cs becomes noise that determines a detectable signal level. An object of the present invention is to provide an imaging device capable of reducing noise due to a leak current of the TFT.

In particular, when a human body is observed through a transmission, it is preferable that a weak signal can be detected in order to minimize the influence on the human body. It is also necessary to prevent dielectric breakdown due to application of a pixel voltage to the protection diode.

As described above, an object of the present invention is to provide an imaging device capable of reducing the value of the off-state current of the protection TFT and its variation.

It is another object of the present invention to provide an imaging device capable of preventing dielectric breakdown of a protection diode.

Recently, an a-Si TFT has been used as an X-ray diagnostic apparatus.
(Amorphous silicon thin film transistor) An imaging apparatus using an imaging device has been proposed (for example, US46).
89487). FIG. 49 shows the configuration of this imaging apparatus.
The outline of the iTFT imaging device is shown in FIG. 50, and the operation will be described below.

FIG. 49 is an overall configuration diagram of an image pickup apparatus using an a-Si TFT. The X-rays emitted from the X-ray source 251 pass through the subject 252 and enter the a-Si TFT imaging device 253. a-SiTFT imaging device 253
Converts into an analog electric signal corresponding to the X-ray dose passed through the subject 252. The converted analog signal is digitally converted by the A / D converter 257 in a time series and stored in the image memory 258. Image memory 258 is 1
Data for one sheet or several images can be stored, and data is sequentially stored at a specific address by a control signal from the control unit 263. The arithmetic processing unit 259 includes the image memory 25
The data is taken out from 8 and operated, and the result is returned to the image memory again. The calculated data in the image memory 258 is converted into an analog signal by the D / A converter 260 and displayed on the monitor 261 as an X-ray image.

FIG. 50 shows an a-Si TFT, an imaging device 2
It is a figure showing the outline of 53. In FIG. 50, pixels e ₁ ,
Reference numeral ₁ denotes an a-Si TFT 274, a photoelectric conversion film 270, and a pixel capacitor 273.
It is in the form of an array of 00 (hereinafter referred to as a TFT array). A bias voltage is applied to the photoelectric conversion film 270 from the power supply 271. The a-Si TFT 274 is connected to the signal line S1.
And the scanning line G 1, and ON / OFF is controlled by the scanning line driving circuit 277. The end of the signal line S1 is connected to an amplifier 276 for signal detection.

When light enters, a current flows through the photoelectric conversion film 270 and charges are accumulated in the pixel capacitance 273. When the scanning line is driven by the scanning line driving circuit 277 and all the TFTs connected to one scanning line are turned on, the accumulated charges are transferred to the amplifier 276 through the signal line S1. The amount of charge varies depending on the amount of light incident on the pixel, and the output amplitude of the amplifier 276 changes.

In the method shown in FIG. 50, a digital image can be directly obtained by A / D converting the output signal of the amplifier 276. Further, the pixel area in the figure has the same structure as a TFT-LCD (thin film transistor liquid crystal display) used in a notebook personal computer, and a thin and large screen can be easily manufactured.

In FIG. 50, one a-SiT per pixel is used.
Although the configuration of the FT is shown, in an actual device, a pixel may be composed of a plurality of a-Si TFTs. In some cases, an a-Si TFT is provided outside the pixel region. For example, in the case of a configuration in which a diode in a pixel is provided as shown in FIG. 51, or as shown in FIG. 52, the accumulated charge is converted into a voltage and output (AMI (AmplifiedM)).
OSImager structure) method.

Although an X-ray diagnostic apparatus requires a high S / N ratio and a wide dynamic range, it is an essential condition that the characteristics of a plurality of a-Si TFTs in a pixel in the above-described structure be uniform. Variations in TFT characteristics, particularly variations in off-resistance and variations in Vth, cause deterioration in image quality of a detected image. The fact that the off resistance varies means that the leak current cannot be suppressed to the minimum, and an increase in noise due to the leak current, that is, S / N
This leads to a decrease in ratio and dynamic range. Vth
Is an offset of the output signal and causes fixed pattern noise.

Further, since there is a temporal change in Vth, it is necessary to collect correction data for each photographing in order to obtain a good image, and there is a problem that the working efficiency is reduced.

As described above, a plurality of a-SiTs are provided in a pixel.
When forming an FT or an AMI structure, a-SiTF
There is a problem that it is not possible to obtain a good image with a high S / N and a wide dynamic range due to variations in the characteristics of T.

This variation in TFT characteristics often occurs because the shape of the TFT varies due to a mask position shift during the manufacture of the TFT array. Therefore, in order to make the TFT characteristics uniform, it is necessary to make the shape of the TFT uniform.

FIG. 53 shows a method of manufacturing a TFT array.
FIG. 53 shows the case where a source electrode and a drain electrode are formed. Electrode material metal (for example, Al, Mo
Are laminated (1), a resist is applied (2), and the resist is exposed (3) and etched (4) using a mask to form an electrode. When forming a TFT, each layer (gate electrode formation, insulating layer, pixel electrode formation, etc.)
Use the necessary mask for each layer to perform in
In order to make the TFT shape as designed, it is necessary to precisely match the positions of these masks. However, since a mask misalignment is inevitable to some extent, it is important to anticipate the mask misalignment when designing a TFT array and to design the TFT array to obtain desired performance even in the worst case.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide an image pickup apparatus provided with a TFT having no variation in characteristics even when a mask misalignment occurs. .

L. S. Jeromin et al. Have announced a two-dimensional X-ray detector in which an amorphous Se layer for converting X-rays into electric charges is stacked on an a-Si (amorphous silicon) TFT (thin film transistor) array (SID 97).
DIGEST (1997) p. 91).

FIG. 55 shows a conventional TFT for a two-dimensional X-ray detector.
2 shows an array. This TFT is a top gate type a-Si type. An SiOx film 302 is formed on a glass substrate 1, a drain electrode 313, a source electrode 303 made of ITO, and a capacitor lower electrode 305 are formed.
An Si layer 304 is formed, a capacitor insulating film 306 is formed, a gate insulating film 307 is formed, and a gate electrode 3
09, a passivation film 310 is formed, a capacitor upper electrode 208 is formed, and a pixel electrode 311 made of ITO is formed. Here, a SiNx film is generally used for the passivation film 310. However, since SiNx has a low step coverage, an interlayer short-circuit is likely to occur between the gate electrode 309 and the pixel electrode 311 and the production yield is low. Also, SiN
Since x is formed by a CVD process, it is difficult to increase the film thickness, and x is generally formed with a thickness of about 2000 to 3000 A (angstrom). Such thin SiNx
When a film is used, a capacitance is generated between the gate electrode 309 and the pixel electrode 311, which causes distortion or delay of a gate signal pulse.

In the conventional flat X-ray detector, ITO is used as a pixel electrode. A chest imaging detector requires a pixel area of 40 cm × 40 cm. It is difficult to deposit a uniform ITO film on such a large area. ITO is patterned using a hydrochloric acid-based etchant using a photoresist as a mask material, but ITO has a different etch rate due to a difference in crystallinity due to a difference in crystallinity. The lower the crystallinity, the faster the etch rate. The higher the crystallinity, the lower the etching rate. The etching is performed until the etching of the portion having the lowest etching rate in the plane is completely completed. At this time, excessive etching is performed in portions where the etching rate is high. In particular, ITO on an organic insulating film is composed of an organic insulating film and ITO.
The crystallinity of ITO at the interface of is low and close to amorphous. For this reason, the etching rate at the interface is very high, so that the etching solution permeates and causes large side etching. When the overetching time of the 1500A ITO was etched in a pixel area of 8 cm × 8 cm with an overetching time of 10%, the side etching amount was 0.5 μm at the minimum and 10 μm at the maximum. In this case, the pixel electrode resist pattern size is 100 μm × 100 μm
In this case, the maximum pixel area is 9900 μm ² , the minimum pixel area is 6400 μm ² , and the minimum pixel area is 64.6% of the maximum pixel area. If there is such a variation in the pixel area between the pixels, the signal amount varies and an accurate image cannot be obtained.

The present invention has been made in order to solve the above-mentioned problem, and it is intended to prevent a decrease in production yield due to an interlayer short-circuit failure when using SiNx for an insulating film below a pixel electrode. Provided is an imaging device that reduces capacitance between electrodes and prevents a reading error in signal intensity between pixels due to a variation in pixel electrode area between pixels that occurs when ITO is used as a pixel electrode. With the goal.

Recently, an a-Si TFT has been used as an X-ray diagnostic apparatus.
(Amorphous silicon thin film transistor) An imaging apparatus using an imaging device has been proposed (for example, US46).
89487). The configuration of this imaging device is shown in FIG.
The outline of the TFT imaging device is shown in FIG. 50, and the operation will be described below.

FIG. 49 is an overall configuration diagram of an imaging device using an a-Si TFT. The X-rays emitted from the X-ray source 251 pass through the subject 252 and enter the a-Si TFT imaging device 253. a-SiTFT imaging device 253
Converts into an analog electric signal corresponding to the X-ray dose passed through the subject 252. The converted analog signal is digitally converted by the XD converter 257 in a time series and stored in the image memory 258. The image memory 258 can store data of one image or several images, and sequentially stores data at a specific address by a control signal from the control unit 263. The arithmetic processing unit 259 includes an image memory 258
The data is calculated from the data, and the result is returned to the image memory again. The calculated data in the image memory 258 is converted into an analog signal by the D / A converter 260 and displayed on the monitor 261 as an X-ray image.

FIG. 50 shows an a-Si TFT imaging device 25.
FIG. 3 is a diagram showing an outline of No. 3; In FIG. 50, pixels e ₁ , ₁
Is composed of an a-Si TFT 274, a photoelectric conversion film 270, and a pixel capacitor 273.
It is in the form of zero array (hereinafter referred to as TFT array). A bias voltage is applied to the photoelectric conversion film 270 from the power supply 271. The a-Si TFT 274 is connected to the signal line S <b> 1 and the scanning line G <b> 1, and ON / OFF is controlled by the scanning line driving circuit 277. The end of the signal line S1 is connected to an amplifier 276 for signal detection.

When light enters, a current flows through the photoelectric conversion film 270, and charges are accumulated in the pixel capacitance 273. When the scanning line is driven by the scanning line driving circuit 277 and all the TFTs connected to one scanning line are turned on, the accumulated charges are transferred to the amplifier 276 through the signal line S1. The amount of charge varies depending on the amount of light incident on the pixel, and the output amplitude of the amplifier 276 changes. The system shown in FIG.
A / D conversion of the output signal of the above makes it possible to directly make a digital image.

By the way, when a TFT array is manufactured, a TFT defect may occur due to static electricity, causing a point defect or a line defect in a detected image, which has a problem that a displayed image is significantly deteriorated.

The present invention has been made to solve the above problems. That is, an object of the present invention is to provide an imaging apparatus which does not cause a TFT defect due to static electricity and does not cause a point defect or a line defect in a detected image.

[0047]

According to a first aspect of the present invention, there is provided an image pickup apparatus comprising: a photoelectric conversion film; a signal line disposed in a matrix and connected to the photoelectric conversion film; A switching element that opens and closes between the photoelectric conversion film and the signal line; a scanning line that sends a drive signal to the switching element; and a charge connected to each of the photoelectric conversion films and stored in the photoelectric conversion film. A protection non-linear element that causes excess charge to flow to the bias line when the amount exceeds a certain amount, and an insulating layer interposed between the scanning line and the bias line.

According to a second aspect of the present invention, there is provided an image pickup apparatus, comprising: a substrate; a plurality of pixel electrodes disposed in a matrix on the substrate;
A non-linear element for protection or a bias line disposed so as to be covered with the pixel electrode.

According to a third aspect of the present invention, there is provided an image pickup apparatus, wherein a plurality of pixel electrodes arranged in a matrix, a first thin film transistor connected to each pixel electrode, and each pixel electrode are connected to each other. A second thin film transistor disposed so that a channel direction is parallel to the first thin film transistor.

According to a fourth aspect of the present invention, there is provided an imaging device, wherein a photoelectric conversion film is disposed adjacent to the photoelectric conversion film;
u, Cu, Ni, Co, Fe, Ti, Pt, Zr, C
a metal selected from the group consisting of r, V, Nb, Mo, Ta, and W; or an alloy containing one or more metals selected from the group; or Al, Ag, Nd, Au, Sm, and C
u, Mn, Si, Ni, Co, Y, Fe, Sc, Pd,
Ti, Pt, Zr, Cr, V, Rh, Hf, Ru, B,
A pixel electrode formed of an alloy obtained by adding one or more metals selected from the group consisting of Ir, Nb, Mo, Ta, Os, Re, and W.

According to a fifth aspect of the present invention, in the image pickup apparatus, a plurality of pixel electrodes formed in a matrix, a signal line connected to each of the pixel electrodes, and each of the pixel electrodes and the signal lines are opened and closed. A first region formed by a switching element and a scanning line for sending a drive signal to the switching element; and a first region disposed adjacent to the outside of the first region, both ends of the signal line and both ends of the scanning line. A second region in which a portion is disposed, an auxiliary line disposed in the second region, a portion between the signal line and the auxiliary line in the second region, and Electrostatic discharge means interposed between the auxiliary wiring and short-circuiting when the potential difference between the signal line and the scanning line is equal to or more than a predetermined value to make the signal line and the scanning line equipotential; In the imaging apparatus according to the first aspect of the present invention, the scanning line and Wherein arranged on the bias line and separate the layers, the insulating layer between them is interposed, it is not possible to produce a short circuit between the scanning line and the bias line, the yield is improved.

In a direct conversion type X-ray flat panel detector, a fluoroscopic mode is made possible by using a protection diode as a measure against a high voltage that can be applied to the reading TFT. In order to make full use of the voltage, it is necessary to supply a voltage to the protection diode. Therefore, an X-ray flat panel detector and a TFT that avoid new noise on the signal due to the routing of the power supply line
It is possible to obtain an X-ray flat panel detector in which the production yield of the array is hardly reduced, and an X-ray flat panel detector which prevents a decrease in the yield and reduces a reduction in the area for the pixel capacitance due to the protection diode and the power supply line. I can do it.

In the image pickup apparatus according to the second aspect of the present invention, the protection diode is provided between the substrate and the pixel electrode, and is provided so as to be covered by the pixel electrode. The electrode functions as a shield for the protection diode. Therefore, the protection diode is hardly affected by the incident X-ray, and the protection TFT
This prevents fluctuations in the off-state current and dielectric breakdown of the protection diode.

In a direct conversion type X-ray flat panel detector, as a measure against a high voltage that can be applied to the reading TFT, the use of a protective diode enables a fluoroscopic mode, and a sufficiently weak signal is measured. For this purpose, it is necessary to reduce the off-current of the protection TFT and its fluctuation. In the present invention, since the insulating film is provided, the protection TFT
Leakage current and its fluctuation can be reduced.
In addition, application of an excessive voltage to the protection diode can be prevented.

In the imaging apparatus according to the third aspect of the present invention, the first thin film transistor and the second thin film transistor are arranged so that their respective channel directions are parallel to each other. Occurs, Vth and off-state current are offset between the thin film transistors in the same pixel. As a result, an image pickup device including a thin film transistor having no variation in characteristics can be obtained.

Here, the “channel direction” is a semiconductor layer provided between a source electrode and a drain electrode of a thin film transistor, and refers to a path along which electrons and holes move.

When there are a plurality of thin film transistors in a pixel, by making the channel directions of the thin film transistors parallel, it is possible to make the shape of the thin film transistor uniform even if a mask misalignment occurs, thereby suppressing variation in characteristics. be able to. Therefore, it is possible to suppress an increase in noise due to the characteristic variation, thereby improving the detected image and the working efficiency.

According to the present invention, the pixel electrode is disposed adjacent to the photoelectric conversion film, and the pixel electrode is formed of Ag, Au, Cu, Ni, Co, Fe, Ti, P
a metal selected from the group consisting of t, Zr, Cr, V, Nb, Mo, Ta, and W, or an alloy containing one or more metals selected from the group; or Al, Ag, Nd, A
u, Sm, Cu, Mn, Si, Ni, Co, Y, Fe,
Sc, Pd, Ti, Pt, Zr, Cr, V, Rh, H
f, Ru, B, Ir, Nb, Mo, Ta, Os, Re,
Since it is formed from an alloy to which one or more metals selected from the group consisting of W are added, it is possible to prevent a change in resolution due to side etching and a hillock in a pixel electrode.

In the present invention, a benzocyclobutene-based resin, an acrylic resin, or a polyimide-based resin is used for an interlayer insulating film below a pixel electrode, and an Al alloy or a metal having a melting point higher than Al is used for a pixel electrode.

The organic insulating film can be formed by applying a raw material on a substrate by spin coating and then baking the same, so that it is easy to form a thick film of 3 μm or more. By using an organic insulating film having a low dielectric constant and a thicker film instead of SiNx as an insulating film below the pixel electrode, the capacitance of the pixel electrode and the lower electrode wiring can be reduced, and thus the electrode wiring can be reduced. Signal pulse distortion and delay can be prevented. In addition, by increasing the film thickness, it is possible to prevent an interlayer short-circuit defect occurring between the pixel electrode and the lower electrode wiring, thereby improving the production yield.

According to a fifth aspect of the present invention, in the image pickup apparatus, the second region is interposed between the signal line and the auxiliary wiring and between the scanning line and the auxiliary wiring, When a potential difference between the signal line and the scanning line is equal to or more than a predetermined value, an electrostatic discharge unit is provided to short-circuit and make the signal line and the scanning line equipotential. It is possible to prevent a short circuit therebetween from breaking the thin film transistor.

The wiring of the electrostatic breakdown preventing TFT connected to the signal line is kept at the same potential as the signal line, and the wiring of the electrostatic breakdown preventing TFT connected to the scanning line is connected to the scanning line. Since the potentials are the same, current does not flow through the TFT, and the occurrence of thermal noise, which is a noise source, is prevented. Furthermore,
All the wirings of the TFTs for preventing electrostatic destruction are made common during the manufacture of the array, and are separated into the signal line side and the scanning line side after the completion of the array. This makes it possible to supply a suitable potential to each of the signal line and the scanning line.

The following modifications are conceivable for each of the first to fifth aspects of the present invention.

First, the following modifications 1 to 4 can be considered for the invention described in claim 1. (Modification 1) Charge conversion means provided corresponding to each of a plurality of pixels arranged on the detection surface and converting incident X-rays into charges, provided corresponding to each of the charge conversion means, Charge storage means for storing the charge converted by the charge conversion means, charge read means provided corresponding to each of the charge storage means for reading the charge stored by the charge storage means, and each of the charge read means And the electric charge stored in the electric charge accumulating means when the applied voltage is equal to or higher than a predetermined voltage lower than the voltage at which the electric charge reading means is destroyed, which is connected to the input side of the electric charge reading means. An X-ray imaging apparatus for a medical X-ray diagnostic apparatus, characterized in that the power supply line for the charge sweeping means is provided in parallel with a signal line. X of medical X-ray diagnostic apparatus
Line imaging device.

(Modification 2) Charge conversion means provided corresponding to each of a plurality of pixels arranged on the detection surface and converting incident X-rays into electric charge, and corresponding to each of the charge conversion means A charge storage means for storing the charge converted by the charge conversion means; a charge read means provided for the charge storage means for reading the charge stored by the charge storage means; It is provided corresponding to the charge readout means, is connected to the input side of the charge readout means, and is stored in the charge storage means when the applied voltage is equal to or higher than a predetermined voltage lower than a voltage that destroys the charge readout means. And a sweeping means for sweeping out the electric charge, in the X-ray imaging apparatus of a medical X-ray diagnostic apparatus, characterized in that the power supply line for the charge sweeping means,
An X-ray imaging apparatus for a medical X-ray diagnostic apparatus, which is installed in parallel with a scanning line.

(Modification 3) Charge conversion means provided for each of a plurality of pixels arranged on the detection surface and converting incident X-rays into electric charge, and a charge conversion means corresponding to each of the charge conversion means A charge storage means for storing the charge converted by the charge conversion means; a charge read means provided for the charge storage means for reading the charge stored by the charge storage means; It is provided corresponding to the charge readout means, is connected to the input side of the charge readout means, and is stored in the charge storage means when the applied voltage is equal to or higher than a predetermined voltage lower than a voltage that destroys the charge readout means. An X-ray imaging apparatus for a medical X-ray diagnostic apparatus, comprising: a plurality of power supply lines and a plurality of scanning lines including the charge sweeping means. An X-ray imaging apparatus for a medical X-ray diagnostic apparatus, wherein at least two wirings are installed via an insulating film.

(Modification 4) In the X-ray imaging apparatus of Modification 3, when the power supply line for the charge sweeping means is installed in two layers in parallel with the scanning line, an insulating film introduced between the layers is used. An X-ray imaging apparatus for a medical X-ray diagnostic apparatus, wherein the capacity in a pixel is increased.

With respect to the invention described in claim 2, the following modification 5 can be considered.

(Modification 5) Charge conversion means provided for each of a plurality of pixels arrayed on the detection surface, for converting incident X-rays into electric charge, and for each of the charge conversion means A charge storage means for storing the charge converted by the charge conversion means; a charge read means provided for the charge storage means for reading the charge stored by the charge storage means; It is provided corresponding to the charge readout means, is connected to the input side of the charge readout means, and is stored in the charge storage means when the applied voltage is equal to or higher than a predetermined voltage lower than a voltage that destroys the charge readout means. A protection device that sweeps out a charge that has been applied, and an X-ray imaging apparatus for a medical X-ray diagnostic apparatus, comprising: a protection device and a pixel electrode or a protection device bias line. An X-ray imaging apparatus for a medical X-ray diagnostic apparatus, wherein an organic insulating film is formed between pixel electrodes.

Regarding the invention described in claim 3, the following modifications 6 to 13 can be considered.

(Modification 6) A signal electrode and a scanning line are arranged in a matrix, and a pixel electrode in which a photoelectric conversion film disposed between the signal line and the scanning line is laminated; Thin film transistor (TFT) arranged between
And a signal readout circuit for reading charges accumulated in the pixel electrodes, and a scanning line driving circuit for driving the scanning lines, wherein the photoelectric conversion device is disposed between the signal lines and the scanning lines. In one pixel region including a pixel electrode in which a film is stacked and a plurality of thin film transistors arranged between the signal line and the scanning line, the channel directions of the plurality of thin film transistors in the pixel region are parallel. Characteristic imaging device.

(Modification 7) A signal electrode and a scanning line are arranged in a matrix, and a pixel electrode in which a photoelectric conversion film is interposed between the signal line and the scanning line, and the signal line and the scanning line are arranged. Thin film transistor (TFT) arranged between
A constant current source circuit formed of a thin film transistor connected to the signal line, a signal readout circuit for reading charges stored in the pixel electrode, and a scan line drive circuit for driving the scan line In the apparatus, a pixel electrode in which a photoelectric conversion film is disposed between the signal line and the scanning line, a pixel electrode in which a photoelectric conversion film is disposed between the signal line and the scanning line, and the thin film transistor An imaging device, wherein in one pixel region comprising: a thin film transistor forming a constant current source circuit connected to the signal line; and a channel direction of the thin film transistor in the one pixel region is parallel.

(Modification 8) A signal electrode and a scanning line are arranged in a matrix, and a pixel electrode in which a photoelectric conversion film disposed between the signal line and the scanning line is laminated; the signal line and the scanning line; Thin film transistor (TFT) arranged between
And a signal readout circuit for reading charges stored in the pixel electrode and a scanning line driving circuit for driving the scanning line, wherein the channel direction of the thin film transistor is parallel. apparatus.

(Modification 9) A signal electrode and a scanning line are arranged in a matrix, and a pixel electrode in which a photoelectric conversion film disposed between the signal line and the scanning line is laminated; Thin film transistor (TFT) arranged between
A constant current source circuit formed of a thin film transistor connected to the signal line, a signal readout circuit for reading charges stored in the pixel electrode, and a scan line drive circuit for driving the scan line In the device, the thin film transistor and a constant current source circuit formed by the thin film transistor have channel directions parallel to each other.

(Modification 10) A pixel electrode comprising a photoelectric conversion film laminated between the signal line and the scanning line, and a plurality of thin film transistors arranged between the signal line and the scanning line. In one pixel region, the thin film transistor includes one or more thin film transistors that are controlled by the scanning line and read out charges accumulated in the pixel electrode, and one or more thin film transistors that turn on when the pixel electrode potential is equal to or higher than a certain voltage. The imaging device according to Modification Example 6 or 8, wherein

(Modification 11) A pixel electrode including a photoelectric conversion film laminated between the signal line and the scanning line and a plurality of thin film transistors disposed between the signal line and the scanning line. In one pixel region, the thin film transistor is controlled by the scan line to read out the charge stored in the pixel electrode, one or more thin film transistors, the one or more thin film transistors whose pixel electrode potential is turned on at a certain potential or more, A modification characterized by comprising one or more thin film transistors connected to the gate electrodes of one or more thin film transistors that turn on when the pixel electrode potential is higher than a certain voltage, and outputting a potential biased by a certain potential from the pixel electrode potential. 9. The imaging device according to 6 or 8.

(Modification 12) A pixel electrode comprising a photoelectric conversion film laminated between the signal line and the scanning line, and a plurality of thin film transistors disposed between the signal line and the scanning line. In one pixel region, the thin film transistor is controlled by the scanning line, and reads one or more thin film transistors stored in the pixel electrode; one or more thin film transistors that fix the pixel electrode potential to a constant potential; The imaging device according to the seventh or ninth modification, comprising: one or more thin film transistors that are turned on when an electrode potential is equal to or higher than a certain voltage.

(Modification 13) A pixel electrode comprising a photoelectric conversion film laminated between the signal line and the scanning line, and a plurality of thin film transistors disposed between the signal line and the scanning line. In one pixel region, the thin film transistor is controlled by the scanning line, and reads one or more thin film transistors stored in the pixel electrode; one or more thin film transistors that fix the pixel electrode potential to a constant potential; One or more thin-film transistors that turn on when the electrode potential is higher than a certain potential, and a potential that is connected to the gate electrode of one or more thin-film transistors that turns on when the pixel electrode potential is more than a certain voltage and is biased by a certain potential from the pixel electrode potential is output. Modification 7 or 9 characterized by comprising one or more thin film transistors
An imaging device according to claim 1.

Regarding the invention described in claim 4, the following modified examples 14 to 15 can be considered.

(Modification 14) A plurality of pixel electrodes on which photoelectric conversion films are stacked are arranged, and a thin film transistor which is disposed between a signal line disposed between the pixel electrodes and which is turned on / off by the scanning line; In a photodetector including a signal readout circuit for reading an electrode potential and a scanning line driving circuit for driving the scanning line, the pixel electrodes are Ag, A
u, Cu, Ni, Co, Fe, Ti, Pt, Zr, C
r, V, Nb, Mo, Ta, W, one or more metals selected from the main components, or Al, Ag, Nd, Au, Sm, Cu, Mn, Si, N
i, Co, Y, Fe, Sc, Pd, Ti, Pt, Zr,
Cr, V, Rh, Hf, Ru, B, Ir, Nb, Mo,
A two-dimensional X, which is an alloy to which one or more metals selected from Ta, Os, Re, and W are added;
Line detector.

(Modification 15) A plurality of pixel electrodes each having a stacked photoelectric conversion film are arranged, and a thin film transistor which is disposed between a signal line disposed between the pixel electrodes and is turned on / off by the scanning line; In a photodetector including a signal reading circuit for reading an electrode potential and a scanning line driving circuit for driving the scanning line, most of the pixel electrodes are formed on a benzocyclobutene resin, an acrylic resin, or a polyimide resin. A two-dimensional X-ray detector characterized in that it is formed in a two-dimensional X-ray detector.

The invention described in claim 5 has the following modified examples 16 to 18.

(Modification 16) A plurality of pixel electrodes on which a photoelectric conversion film is laminated are arranged, and a signal line disposed between the pixel electrodes, a scanning line disposed between the pixel electrodes, and a signal Line, and is turned on by the scanning line.
An imaging unit including a first region including a thin film transistor (TFT) to be turned off, and a second region around the first region and including the signal line and the scanning line. An image pickup device including a signal readout circuit for reading charges accumulated in the pixel electrodes and a scanning line driving circuit for driving the scanning lines, wherein an auxiliary wiring arranged in the second region; An image pickup apparatus comprising: static electricity prevention means formed by electrostatic discharge means formed between at least one wiring between a wiring and the signal line and between at least one wiring between the auxiliary wiring and the scanning line (Modification 17) A plurality of pixel electrodes each having a stacked photoelectric conversion film are arranged, a signal line disposed between the pixel electrodes, a scanning line disposed between the pixel electrodes, and a pixel line disposed between the pixel electrodes and the signal lines. The run A first region constituted out with a thin film transistor (TFT) for turning on and off the line,
An imaging unit that is located around the first region and includes the signal line and the second region where the scanning line is arranged, a signal readout circuit that reads charges accumulated in the pixel electrode, In an imaging device configured with a scanning line driving circuit that drives a scanning line, in the second region, the signal line is connected to first auxiliary wiring by electrostatic discharge means,
The first auxiliary wiring is fixed at a first potential, the scanning line is connected to a second auxiliary wiring by electrostatic discharge means in the second area, and the second auxiliary wiring is a second auxiliary wiring. An imaging apparatus characterized in that the electrostatic discharge means is fixed to a potential. (Modification 18) The electrostatic discharge means arranged in the second area is constituted by one or more thin film transistors or one or more diodes. An imaging device according to Modification 16 or 17, which is a feature.

[0084]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) The function of an X-ray imaging apparatus according to a first embodiment of the present invention will be described below.

FIG. 1 is a plan view of an X-ray imaging apparatus according to the first embodiment of the present invention.

As shown in FIG. 1, the pixel is a read TF.
T1, pixel electrode 3, protection diode 5, signal readout line (signal line) 7, gate line (scanning line) 9, auxiliary electrode 11,
It is composed of a power line 13 for the protection diode. However, in FIG. 1, the protective film 41, the common electrode 45, the X-ray charge conversion film 43, and those disposed outside the pixels are omitted. As an example of the function, the pixel capacitance Cst15 includes the pixel electrode 3 and the auxiliary electrode 11, and the charge generated by the X-ray incident on the X-ray charge conversion film 43 is Cst.
When the electric charge is accumulated in the pixel 15 and reaches a certain voltage that does not cause the dielectric breakdown of the TFT 1, the electric charge flows out of the pixel from the protection diode 5, and the readout TFT 1 and the Cs
At t15, no high voltage is applied. The outflow path of the electric charge at this time is the power line 13 for the diode, and the voltage of the start of the electric charge outflow from the protection diode 5 can be changed by setting the potential of the power line 13. The electric charge stored in the pixel is caused to flow to the signal line 7 by scanning the scanning line 9 to turn on each TFT of the pixel on the scanning line. The charge that flows out is transferred to the amplifier.

Next, the configuration will be described with reference to a cross-sectional view of the X-ray imaging apparatus according to the first embodiment.

FIG. 2 is a sectional view of the X-ray imaging apparatus according to the first embodiment.

First, on a glass substrate, metal A47 is
The gate 17 of the FT, the scanning line 9, the auxiliary electrode 11, and the gate 21 of the protection diode TFT are formed. On the upper layer, a gate insulating film 23 is formed. However, the gate insulating film 23 has been removed from the through-hole portion of the protection diode 5. On top of that, the pixel electrode 3
(Metal B'48) is formed in the pixel except for the readout TFT 1 and the protection diode 5, and the readout TFT 1 and the protection diode 5 are a-Si27 and SiNx for the etching stopper on the gate insulating film 23.
29, n ⁺ a-Si 31 are formed, and T
The source 33 and the drain 35, which are the electrodes of the FT, are formed of another metal B49. The metal B49 is composed of the signal line 7, the power line 13 for the protection diode, the drawing pad 1
9 (omitted in FIG. 2), the voltage supply line 25 (FIG.
Is omitted here. ), The source 37 and the drain 39 of the protection diode TFT are also formed.

The pixel electrode 3 may be formed at the same time. However, in that case, the electrode on the pixel electrode side of TFT1 (this is referred to as a source 33), the electrode on the pixel electrode side of the protection diode TFT5 (this is referred to as a source 37), and the pixel electrode 3 is united. Thus, the TFT array is completed.

On the upper layer, a protective film 41, an X-ray charge conversion film 43, and a common electrode 45 made of metal C51 are formed, but are omitted in FIG. With these configurations, an X-ray imaging apparatus of a medical X-ray diagnostic apparatus is formed.

In FIG. 1, one T is used as a protection diode.
An example using FT is given, but two or more T
There may be a case in which FTs are arranged to suppress leakage current from the protection diode, and a case in which a TFT for the protection diode is provided with a low leakage countermeasure.

Although not shown in the figure, an interlayer insulating film 63 is provided on the TFT array described in the first embodiment, and the pixel electrode 3 is in contact with the pixel electrode 3 by a through hole of the interlayer insulating film 63. -Type pixel electrode 6 having the same potential
By providing 5, the aperture ratio (the ratio occupied by the pixel electrode in one pixel) reduced by the increase in the number of power supply lines and the like is set to
This is very effective because the aperture ratio can always be made high regardless of the number of power supply lines and TFTs in the pixel.

As the metal A47, for example, Ti, Cr,
Ta, Mo, MoW, MoTa, Al, ITO, Al alloy and the like, and a laminated structure of these metals are candidates.
Since this metal A47 is used as a gate wiring,
In particular, MoW and MoTa are excellent because they can be etched by tapering the gate portion of the TFT, and can be formed so that the gate insulating film 23 laminated thereover does not cause disconnection. I can say. In addition, in the case of an Al alloy, hillocks generated when a high-temperature process is performed can be prevented by using only Al, so that a gate line having a lower resistance can be obtained. It can be said that.

As the metal B'48, for example, Ti, C
r, Ta, Mo, MoW, MoTa, Al, ITO, A
An alloy and a laminated structure of these metals are candidates.

As the metal B49, for example, Ti, Cr,
Ta, Mo, MoW, MoTa, Al, ITO, Al alloy, and the like, and a stacked structure of these metals are candidates. Since this metal B49 is used as a signal line,
Low resistance is desired. Therefore, it can be said that Al, a laminated structure using Al, an Al alloy, and the like are excellent. Further, when the metal B'48 is used, it is necessary to adopt an etching method which is not affected by the etching of the metal B49 or an etching method which is not affected.

As the upper type pixel electrode 65, for example, T
i, Cr, Ta, Mo, MoW, MoTa, Al, IT
O and the laminated structure of these metals are candidates. It is necessary to adopt a method in which the metal B49 is not affected when the upper pixel electrode 65 is etched, or an etching method in which the metal B49 is not affected.

As the metal C51 forming the common electrode 45, for example, Ti, Cr, Ta, Mo, MoW, MOT
a, Al, ITO, Al alloy, etc., and a laminated structure of these metals are candidates.

As the gate insulating film 23, for example, Si
O ₂ , SiNx, and SiOxNy can be considered, but a laminated structure of these may be used.

As the protective film 41, an inorganic insulating film, for example, SiNx, SiO ₂ , and an organic insulating film, for example, polyimides, BCB, HRC, black resist, and the like can be used.

As the interlayer insulating film 63, an inorganic insulating film, for example, SiNX, SiO ₂ , and an organic insulating film, for example, polyimides, BCB, HRC, black resist, and the like can be used. As the X-ray charge conversion film 43, a-Se, a-Si
Can be used.

Further, as the type of the TFT 1, an inverted staggered inner etching stopper type was taken as an example, but this is an inverted staggered back channel cut type.
It may be of the type. The etching stopper type does not affect the channel portion when etching the channel portion of the TFT, so that the TFT characteristics hardly vary and is suitable for large arrays. The back channel cut type requires an etching stopper for the process. -Each type has the merit that the manufacturing cost is reduced because it is smaller than the type.

In the Si forming the TFT,
Here, a-Si (amorphous silicon) is used, but if it is formed of poly-Si (poly silicon),
Since the size of the TFT can be reduced, the effective area of the pixel can be increased, and the peripheral circuit can be formed on the same glass substrate. Therefore, there is an advantage that the manufacturing cost including the peripheral circuit is reduced.

Also, here, the method of reading out the charges accumulated in the pixel by using the on / off of the TFT has been described. However, in the nondestructive readout method using the principle of the source follower, the TFT in the pixel is read out. The number of
As a result, the number of power supply lines increases, which is a more effective means.

As described above, in the direct conversion type X-ray flat panel detector which is one of the X-ray imaging apparatuses of the medical X-ray diagnostic apparatus, the power supply line of the protection diode incorporated in the pixel as a measure against the high voltage is replaced with the signal line. By forming in the direction when forming the signal line, the detector can be formed without increasing the parasitic capacitance to the signal line.

(Second Embodiment) Next, a second embodiment will be described.

FIG. 3 is a plan view of an X-ray imaging apparatus according to a second embodiment of the present invention.

The embodiment shown in FIG. 3 is functionally similar to that of FIG.
Is the same as the first embodiment.

However, the power line 13 for the protection diode is not provided in the signal line direction when forming the signal line, but is provided in the scanning line direction when forming the scanning line. This is because when the yield at the time of signal line formation and the yield at the time of scan line formation are compared, the yield at the time of scan line formation is higher.

Next, the configuration will be described with reference to the sectional view of the second embodiment.

FIG. 4 is a sectional view of an X-ray imaging apparatus according to a second embodiment of the present invention.

First, on a glass substrate, metal A47 is
The gate 17 of the FT, the scanning line 9, the auxiliary electrode 11, the gate 21 of the TFT for the protection diode, and the power supply line 13 for the protection diode are formed. On top of that, the gate insulating film 23
Are formed. However, the gate insulating film 23 has been removed from the through-hole portion of the protection diode 5. A pixel electrode 3 (metal B'48) is formed in the pixel above the read TFT 1 and the protection diode 5 except for the read TFT 1 and the protection diode 5. An Si 27, an etching stopper SiNX 29, and an n ⁺ a-Si 31 are formed, and a source 33 and a drain 35, which are electrodes, are formed of another metal B49. The metal B49 includes the signal line 7, the extraction pad 19 (omitted in FIG. 4), the voltage supply line 25 (omitted in FIG. 4), the source 37 and the drain 39 of the protection diode TFT. Is also formed. Further, the pixel electrode 3 may be formed at the same time. However, in this case, the source 33 of the TFT 1, the source 37 of the protection diode TFT 5, and the pixel electrode 3 are integrated. Thus, the TFT array is completed.

On the upper layer, a protective film 41, an X-ray charge conversion film 43, and a common electrode 45 made of metal C51 are formed, but are omitted in FIG. With these configurations, an X-ray imaging apparatus of a medical X-ray diagnostic apparatus is formed.

FIG. 5 is a plan view of an X-ray imaging apparatus according to an example other than the example of FIG.

In addition to the example shown in FIG. 3, as shown in FIG. 5, it is also conceivable that the pixel electrode 3 is provided above the power supply line 13. By doing so, the effective area of the pixel can be increased.

In FIG. 3, 1 is used as the protection diode.
An example of using two TFTs has been given, but two or more TFTs are arranged in series to reduce the leakage current from the protection diode, and the one that has a low leakage countermeasure for the protection diode TFT Conceivable.

In FIG. 3, 1 is used as the protection diode.
An example using three TFTs was given, but three TFTs were used.
In the case of a protection diode in which the leakage current is further reduced by using the method (Japanese Patent Application No. Hei 8-326993), three power supply lines 13 are required instead of one. In this case, the yield during scanning line formation is higher than that during signal line formation,
Four lines including the scanning line 9 may be arranged in parallel in the scanning line direction (FIG. 6), or one of the three power lines (FIG. 7) or two (not shown) may be arranged in the signal line direction. May be provided.

As the latter advantage, since the number of power supply lines crossing the signal lines is reduced, it is possible to prevent the parasitic capacitance of the signal lines from being carelessly increased. Similarly, even if the number of switching TFTs of a pixel, the number of power supply lines for protection diodes, and the number of other wirings are other than those described above, they may be installed taking advantage of the above advantages.

Although not shown, an interlayer insulating film 63 is provided on the TFT array described in the second embodiment, and the pixel electrode 3 and the pixel electrode 3 are brought into contact with each other through through holes in the interlayer insulating film 63 to form the same. By providing the upper type pixel electrode 65 having a potential, the aperture ratio (the ratio of the pixel electrode in one pixel) occupied by the increase in the number of power supply lines and the like can be reduced. It is very effective because the aperture ratio can always be made high regardless of the number.

As the metal A47, for example, Ti, Cr,
Ta, Mo, MoW, MoTa, Al, ITO, Al alloy and the like, and a laminated structure of these metals are candidates.
Since this metal A47 is used as a gate wiring,
In particular, MoW and MoTa are excellent because they can be etched by tapering the gate portion of the TFT, so that the gate insulating film 23 laminated thereon can be formed so as not to cause disconnection. I can say. In addition, in the case of an Al alloy, hillocks generated when a high-temperature process is performed can be prevented by using only Al, so that a gate line having a lower resistance can be obtained. It can be said that.

As the metal B'48, for example, Ti, C
r, Ta, Mo, MoW, MoTa, Al, ITO, A
An alloy and a laminated structure of these metals are candidates.

As the metal B49, for example, Ti, Cr,
Candidates include Ta, Mo, MoW, MoTa, Al, ITO, and Al alloys, and a laminated structure of these metals. Since this metal B49 is used as a signal line,
Low resistance is desired. Therefore, it can be said that Al, a laminated structure using Al, an Al alloy, and the like are excellent. Further, when the metal B'48 is used, it is necessary to adopt an etching method which is not affected by the etching of the metal B49 or an etching method which is not affected.

As the upper type pixel electrode 65, for example, T
i, Cr, Ta, Mo, MoW, MoTa, Al, IT
O and the laminated structure of these metals are candidates. It is necessary to adopt a method in which the metal B49 is not affected when the upper pixel electrode 65 is etched, or an etching method in which the metal B49 is not affected.

As the metal C51 forming the common electrode 45, for example, Ti, Cr, Ta, Mo, MoW, MoT
a, Al, ITO, Al alloy, etc., and a laminated structure of these metals are candidates.

As the gate insulating film 23, for example, Si
O ₂ , SiNx, and SiOxNy can be considered, but a laminated structure of these may be used.

As the protective film 41, an inorganic insulating film, for example, SiNx, SiO ₂ and an organic green film, for example, polyimides, BCB, HRC, black resist and the like can be used.

As the interlayer insulating film 63, an inorganic insulating film, for example, SiNx, SiO ₂ , and an organic insulating film, for example, polyimides, BCB, HRC, Teflon resin, black resist, and the like can be used. As the X-ray charge conversion film 43,
a-Se and a-Sl can be used.

In addition, as an example of the type of the TFT 1, an inverted stagger type inner etching stopper type is described as an example. This is an inverted stagger type back channel cut type.
It may be of the type.

For the etching stopper type, TF
Since the channel portion is not corroded at the time of etching the channel portion of T, variation in TFT characteristics hardly occurs and is suitable for a large array, and the back channel cut type requires fewer steps than the etching stopper type. Therefore, there is an advantage that the manufacturing cost is reduced.

Further, in Si forming a TFT,
Here, a-Si (amorphous silicon) is used, but if it is formed of poly-Si (poly silicon),
Since the size of the TFT can be reduced, the effective area of the pixel can be increased, and the peripheral circuit can be formed on the same glass substrate. Therefore, there is an advantage that the manufacturing cost including the peripheral circuit is reduced.

Also, here, the method of reading out the charges accumulated in the pixel by using the on / off of the TFT has been described. However, in the nondestructive readout method using the principle of the source follower, the TFT in the pixel is read out. The number of
As a result, the number of power supply lines increases, which is a more effective means.

As described above, in the direct conversion type X-ray flat panel detector which is one of the X-ray imaging apparatuses of the medical X-ray diagnostic apparatus, the yield is higher when forming the scanning lines than when forming the signal lines. By forming a bias line of a protection diode incorporated in a pixel as a countermeasure against a high voltage by forming a bias line in the scanning line direction at the time of forming the scanning line, it is possible to prevent a decrease in yield and to form a detector.

(Third Embodiment) Next, a third embodiment will be described.

The example shown in FIG. 8 is functionally the same as the example shown in FIG. However, the power line 13 for the protection diode is provided in the signal line direction, but is not provided at the time of forming the signal line. Instead, an insulating film is placed on the signal line and provided separately thereover. This is because if the power supply line is formed in the same layer as the signal line in the signal line direction, the yield is reduced. Therefore, the power supply line is intentionally formed in another layer to increase the yield.

Next, the configuration will be described with reference to a cross-sectional view (FIG. 9) of the third embodiment.

First, the metal A47 forms the gate 17, the scanning line 9, the auxiliary electrode 11, and the gate 21 of the protection diode TFT on the substrate. A gate insulating film 23 is formed thereon. However, the gate insulating film 23 has been removed from the through-hole portion of the protection diode 5. In the upper layer, the pixel electrode 3 (metal B'48) is formed in the pixel except for the readout TFT I and the protection diode 5, and for the readout TFT 1 and the protection diode 5, a -Si27, SiNX29 for etching stopper,
An n ⁺ a-Si 31 is formed, on which a source 33 and a drain 35 as electrodes are formed of another metal B49. The metal B49 includes the signal line 7, the lead pad 19 (not shown in FIG. 9), and the voltage supply line 25.
(Omitted in FIG. 9), TFT for protection diode
The source 37 and the drain 39 are also formed. Also,
The pixel electrode 3 may be formed at the same time. However, in this case, the source 33 of the TFT 1 and the TFT 5 for the protection diode are used.
The source 37 and the pixel electrode 3 are integrated. An insulating film b57 is provided thereabove, and a power supply line 13 for the protection diode is further formed on the insulating film b57 in parallel with the signal lines using a metal E59. Further, for example, the pixel electrode 3 is connected to the metal E5.
9 may be formed. The protection diode 5 and the power line 13 for the protection diode are connected to the insulating film b5 near the protection diode 5.
7 are contacted through through holes. In addition, the insulating film b57 forms a through hole with the pixel electrode 3 and the like. Thus, the TFT array is completed.

On the upper layer, a protective film 41, an X-ray charge conversion film 43, and a common electrode 45 made of metal C51 are formed, but are omitted in FIG. With these configurations, an X-ray imaging apparatus of a medical X-ray diagnostic apparatus is formed.

Although illustration is omitted except for the example of FIG. 8, when the power supply line 13 is formed by the metal E59, the power supply line 13 may be arranged in the scanning line direction.

In FIG. 8, one T diode is used as a protection diode.
An example using FT is given, but two or more T
There may be a case in which FTs are arranged to suppress leakage current from the protection diode, and a case in which a TFT for the protection diode is provided with a low leakage countermeasure.

Although not shown, an interlayer insulating film 63 is provided on the TFT array described in the third embodiment, and the pixel electrode 3 is in contact with the pixel electrode 3 through a through hole of the interlayer insulating film 63. By providing the upper type pixel electrode 65 having the same potential, the aperture ratio (the ratio of the pixel electrode in one pixel) occupied by the increase in the number of power supply lines can be reduced by the power supply line in one pixel or the like. This is very effective because the aperture ratio can always be increased regardless of the number of TFTs.

As the metal A47, for example, Ti, Cr,
Ta, Mo, MoW, MoTa, Al, ITO, Al alloy and the like, and a laminated structure of these metals are candidates.
Since this metal A47 is used as a gate wiring,
In particular, MoW and MoTa are excellent because they can be etched by tapering the gate portion of the TFT, and can be formed so that the gate insulating film 23 laminated thereover does not cause disconnection. I can say. In addition, in the case of an Al alloy, hillocks generated when a high-temperature process is performed can be prevented by using only Al, so that a gate line having a lower resistance can be obtained. It can be said that.

As the metal B'48, for example, Ti, C
r, Ta, Mo, MoW, MoTa, Al, ITO, A
An alloy and a laminated structure of these metals are candidates.

As the metal B49, for example, Ti, Cr,
Candidates include Ta, Mo, MoW, MoTa, Al, ITO, and Al alloys, and a laminated structure of these metals. Since this metal B49 is used as a signal line,
Low resistance is desired. Therefore, it can be said that Al, a laminated structure using Al, an Al alloy, and the like are excellent. Further, when the metal B'48 is used, it is necessary to adopt an etching method which is not affected by the etching of the metal B49 or an etching method which is not affected.

As the metal E59, for example, Ti, Cr,
Candidates include Ta, Mo, MoW, MoTa, Al, ITO, and Al alloys, and a laminated structure of these metals. However, at the time of etching the metal E59, it is necessary to adopt a method in which the metal B'48 and the metal B49 are not affected, or an etching method in which the metal B'48 and the metal B49 are not affected.

As the upper pixel electrode 65, for example, T
i, Cr, Ta, Mo, MoW, MoTa, Al, IT
O and the laminated structure of these metals are candidates. It is necessary to adopt a method in which the metal B49 is not affected when the upper pixel electrode 65 is etched, or an etching method in which the metal B49 is not affected.

As the metal C51 forming the common electrode 45, for example, Ti, Cr, Ta, Mo, MoW, MoT
a, Al, ITO, Al alloy, etc., and a laminated structure of these metals are candidates.

As the gate insulating film 23, for example, Si
O ² , SiNx, and SiOxNy can be considered, but a laminated structure of these may be used.

As the insulating film b57, an inorganic bleaching film, for example, SiNx, SiO ² , and an organic insulating film, for example, polyimides, BCB, HRC, black resist, and the like can be used.

As the protective film 41, an inorganic insulating film, for example, SiNx, SiO ² and an organic insulating film, for example, polyimides, BCB, HRC, black resist and the like can be used.

As the interlayer insulating film 63, an inorganic insulating film, for example, SiNx, SiO ² , and an organic insulating film, for example, polyimides, BCB, HRC, black resist, and the like can be used. As the X-ray charge conversion film 43, a-Se, a-Si
Can be used.

The type of the TFT 1 is, for example, an inverted staggered inner etching stopper type, which is an inverted staggered back channel cut type.
It may be of the type. The etching stopper type does not affect the channel portion when etching the channel portion of the TFT, so that the TFT characteristics hardly vary and is suitable for large arrays. The back channel cut type requires an etching stopper for the process. -Each type has the merit that the manufacturing cost is reduced because it is smaller than the type.

In the Si forming the TFT,
Here, a-Si (amorphous silicon) is used, but if it is formed of poly-Si (poly silicon),
Since the size of the TFT can be reduced, the effective area of the pixel can be increased, and the peripheral circuit can be formed on the same glass substrate. Therefore, there is an advantage that the manufacturing cost including the peripheral circuit is reduced.

Although the method of reading out the charge accumulated in the pixel by using ON / OFF of the TFT has been described above, the non-destructive read-out method using the principle of the source follower uses the TFT in the pixel. The number of
As a result, the number of power supply lines increases, which is a more effective means.

As described above, in the direct conversion type X-ray flat panel detector which is one of the X-ray imaging apparatuses of the medical X-ray diagnostic apparatus, the power supply line of the protection diode incorporated in the pixel as a measure against high voltage is replaced with the signal line. By forming them in a different layer from the scanning lines, it is possible to better prevent the yield from deteriorating and to form them without impairing the merits of the first and second embodiments.

(Fourth Embodiment) Next, a fourth embodiment will be described.

The example shown in FIG. 10 is functionally the same as the example shown in FIG. However, the power supply line for the protection diode is not provided in the signal line direction when the signal line is formed, but is formed in the scanning line direction on a layer different from the scanning line in the same manner as the scanning line. This is because by forming the scanning lines and the power supply lines in different layers, a short circuit does not occur between these layers, and the deterioration of the yield can be better prevented. Also, various undesired phenomena caused by electrical interference such as noise can be avoided. Further, by forming the scanning line and the power supply line between different layers, the line interval can be reduced, so that the pixel electrode and the pixel capacitance can be formed larger.

Next, the configuration will be described with reference to a cross-sectional view (FIG. 11) of the fourth embodiment.

First, on the substrate, the metal D53 forms the power line 13 for the protection diode. An insulating film a55 is formed thereon. However, the insulating film a55 is removed from the contact portion of the voltage supply line 25 (omitted in FIG. 11), the contact portion between the power supply line 13 and the protection diode 5, and the like. The metal A47 in the upper layer forms the gate 17 of the TFT, the scanning line 9, the auxiliary electrode 11, and the gate 21 of the protection diode TFT. On the upper layer, a gate insulating film 23 is formed. However, the gate insulating film 23 has been removed from the through-hole portion of the protection diode 5. On the upper layer, a pixel electrode 3 (metal B'48) is a TFT 1 for reading.
A-Si 27, an etching stopper SiNx 29, and an n ⁺ a-Si 31 are formed on the gate insulating film 23 in the read TFT 1 and the protection diode 5 except for the TFT 1 and the protection diode 5. The source 33 and the drain 35 serving as electrodes are formed of another metal B49 thereon. This metal B49 is
The signal line 7, the extraction pad 19 (omitted in FIG. 11), the voltage supply line 25 (omitted in FIG. 11), the source 37 and the drain 39 of the protection diode TFT are also formed. . Further, the pixel electrode 3 may be formed at the same time. However, in this case, the source 33 of the TFT 1, the source 37 of the protection diode TFT 5, and the pixel electrode 3 are integrated. Thus, the TFT array is completed.

On the upper layer, a protective film 41, an X-ray charge conversion film 43, and a common electrode 45 made of metal C51 are formed, but are omitted in FIG. Medical X
The X-ray imaging device of the X-ray diagnostic apparatus is formed.

In addition to the example shown in FIG. 10, the one in which the pixel electrode 3 is brought above the power supply line 13 (FIG. 12) and the one in which the power supply line 13 for the protection diode is provided below the scanning line 9 (see FIG. 12). FIG. 13) can be considered.

In this way, the effective area of the pixel can be increased.

In addition to the example shown in FIG. 10, a protection diode power supply line 13 formed of metal D53 may be provided in the signal line 7 direction (FIG. 14). By doing so, not only can the effective area of the pixel be increased, but also the parasitic capacitance on the signal line can be reduced.

In FIG. 10, the protection diode is
An example in which one TFT is used has been given, but two or more TFTs are arranged in series to reduce the leakage current from the protection diode, and the TFT for the protection diode has a low leakage countermeasure. Is also conceivable.

Although not shown in the figure, an interlayer insulating film 63 is provided on the TFT array described in the fourth embodiment, and the pixel electrode 3 and the through-hole of the interlayer insulating film 63 are brought into contact therewith. By providing the upper type pixel electrode 65 having the same potential, the aperture ratio (the ratio of the pixel electrode in one pixel) occupied by the increase in the number of power supply lines can be reduced by the power supply line in one pixel or the like. This is very effective because the aperture ratio can always be increased regardless of the number of TFTs.

As the metal A47, for example, Ti, Cr,
Ta, Mo, MoW, MoTa, Al, ITO, Al alloy and the like, and a laminated structure of these metals are candidates.
Since this metal A47 is used as a gate wiring,
In particular, MoW and MoTa are excellent because they can be etched by tapering the gate portion of the TFT, and can be formed so that the gate insulating film 23 laminated thereover does not cause disconnection. I can say. In addition, in the case of an Al alloy, hillocks generated when a high-temperature process is performed can be prevented by using only Al, so that a gate line having a lower resistance can be obtained. It can be said that.

As the metal D53, for example, Ti, Cr,
Ta, Mo, MoW, MoTa, Al, ITO, Al alloy and the like, and a laminated structure of these metals are candidates.
Since the metal D53 is used in the same situation as the gate wiring, the same can be said for the metal A47.

As the metal B'48, for example, Ti, C
r, Ta, Mo, MoW, MoTa, Al, ITO, A
An alloy and a laminated structure of these metals are candidates.

As the metal B49, for example, Ti, Cr,
Candidates include Ta, Mo, MoW, MoTa, Al, ITO, and Al alloys, and a laminated structure of these metals. Since this metal B49 is used as a signal line,
Low resistance is desired. Therefore, it can be said that Al, a laminated structure using Al, an Al alloy, and the like are excellent. Further, when the metal B'48 is used, it is necessary to adopt an etching method which is not affected by the etching of the metal B49 or an etching method which is not affected.

As the upper type pixel electrode 65, for example, T
i, Cr, Ta, Mo, MoW, MoTa, Al, IT
O and the laminated structure of these metals are candidates. It is necessary to adopt a method in which the metal B49 is not affected when the upper pixel electrode 65 is etched, or an etching method in which the metal B49 is not affected.

As the metal C51 forming the common electrode 45, for example, Ti, Cr, Ta, Mo, MoW, MoT
a, Al, ITO, Al alloy, etc., and a laminated structure of these metals are candidates.

As the gate insulating film 23, for example, Si
O ₂ , SiNx, and SiOxNy can be considered, but a laminated structure of these may be used.

As the insulating film a55, for example, Si
O ₂ , SiNx, and SiOxNy can be considered, but a laminated structure of these may be used.

As the protective film 41, an inorganic insulating film such as SiNx, SiO ₂ and an organic insulating film such as polyimides, BCB, HRC, and black resist can be used.

As the interlayer insulating film 63, an inorganic insulating film such as SiNx, SiO ₂ and an organic insulating film such as polyimides, BCB, HRC, and black resist can be used. As the X-ray charge conversion film 43, a-Se, a-Si
Can be used.

The type of the TFT 1 is, for example, an inverted staggered inner etching stopper type, which is an inverted staggered back channel cut type.
It may be of the type. The etching stopper type does not affect the channel portion when etching the channel portion of the TFT, so that the TFT characteristics hardly vary and is suitable for large arrays. The back channel cut type requires an etching stopper for the process. -Each type has the merit that the manufacturing cost is reduced because it is smaller than the type.

Further, in Si forming a TFT,
Here, a-Si (amorphous silicon) is used, but if it is formed of poly-Si (poly silicon),
Since the size of the TFT can be reduced, the effective area of the pixel can be increased, and the peripheral circuit can be formed on the same glass substrate. Therefore, there is an advantage that the manufacturing cost including the peripheral circuit is reduced.

Although the method of reading out the electric charges accumulated in the pixel by using the ON / OFF of the TFT has been described above, the non-destructive read-out method using the principle of the source follower has been described. The number of
As a result, the number of power supply lines increases, which is a more effective means.

As described above, in the direct conversion type X-ray flat panel detector which is one of the X-ray imaging apparatuses of the medical X-ray diagnostic apparatus, the power supply line of the protection diode incorporated in the pixel as a measure against the high voltage is changed to the scanning line. By forming in a layer different from
A short circuit does not occur between the power supply line and the scanning line, and the deterioration in yield can be better prevented. Further, adverse effects such as generation of harmful noise are suppressed. Further, since the line spacing can be reduced by using different layers, the pixel electrode and the pixel capacitance can be formed larger.

(Fifth Embodiment) Next, a fifth embodiment will be described.

The example shown in FIG. 15 is functionally the same as the example shown in FIG. However, the protection diode introduced into the pixel as a measure against high voltage adopts a device that has less leakage current and less variation between pixels, and scans the power supply lines (plural lines) that have been increased in the scanning line direction. The power line and the power line are formed in different layers. This eliminates short circuits between these scanning lines and the power supply lines and between the power supply lines, thereby preventing a decrease in yield when forming the power supply lines, and also allows the scanning lines and the power supply lines to be placed between different layers. By doing so, the line spacing can be narrowed, so that the pixel electrode and the pixel capacitance can be made larger.

Next, the configuration will be described with reference to a cross-sectional view (FIG. 16) of the fifth embodiment.

First, the power supply line 13 for the protection diode is formed of the metal D53 on the substrate. An insulating film a55 is formed thereon. However, the contact portion of the voltage supply line 25 (omitted in FIG. 16) and the power supply line 13
The insulating film a55 is removed from the contact portion between the protection diode 5 and the like. Metal A47 above it
Form the gate 17, the scanning line 9, the auxiliary electrode 11, the gate 21 of the protection diode TFT, and the power line 13 for the protection diode. On the upper layer, a gate insulating film 23 is formed. However, the gate insulating film 23 has been removed from the through-hole portion of the protection diode 5. In the upper layer, the pixel electrode 3 (metal B'48)
Are formed in the pixel except for the readout TFT 1 and the protection diode 5, and the readout TFT 1 and the protection diode 5 are formed.
Is formed on the gate insulating film 23 by a-Si2
7. SiNx29 for etching stopper, n ⁺ a-S
i31 is formed, and a source 3 serving as an electrode is formed thereon.
3 and the drain 35 are formed of another metal B49.
The metal B49 is used for the signal line 7 and the drawer pad 19.
(Omitted in FIG. 6), voltage supply line 25 (FIG. 15)
Is omitted here. ), The source 37 and the drain 39 of the protection diode TFT are also formed. Further, the pixel electrode 3 may be formed at the same time. However, in that case, T
The source 33 of the FT 1, the source 37 of the protection diode TFT 5, and the pixel electrode 3 are integrated.

Thus, the TFT array is completed.

On the upper layer, a protective film 41, an X-ray charge conversion film 43, and a common electrode 45 made of metal C51 are formed, but are omitted in FIG. Medical X
The X-ray imaging device of the X-ray diagnostic apparatus is formed.

Although not shown in the drawings other than the example of FIG. 14, it is also conceivable that the pixel electrode 3 is provided above the power supply line 13. By doing so, the effective area of the pixel can be increased.

Although not shown, an interlayer insulating film 63 is provided on the TFT array described in the fifth embodiment, and the pixel electrode 3 is in contact with the pixel electrode 3 through a through hole of the interlayer insulating film 63. By providing the upper type pixel electrode 65 having the same potential, the aperture ratio (the ratio of the pixel electrode in one pixel) occupied by the increase in the number of power supply lines can be reduced by the power supply line in one pixel or the like. This is very effective because the aperture ratio can always be increased regardless of the number of TFTs.

The present invention is effective even if the number of TFTs for switching pixels, the number of TFTs for protective diodes, the number of power supply lines, and the number of other wirings are other than those described in the above embodiment.

As the metal A47, for example, Ti, Cr,
Ta, Mo, MoW, MoTa, Al, ITO, Al alloy and the like, and a laminated structure of these metals are candidates.
Since this metal A47 is used as a gate wiring,
In particular, MoW and MoTa are excellent because they can be etched by tapering the gate portion of the TFT, and can be formed so that the gate insulating film 23 laminated thereover does not cause disconnection. I can say. In addition, in the case of an Al alloy, hillocks generated when a high-temperature process is performed can be prevented by using only Al, so that a gate line having a lower resistance can be obtained. It can be said that.

As the metal D53, for example, Ti, Cr,
Ta, Mo, MoW, MoTa, AI, ITO, Al alloy and the like, and a laminated structure of these metals are candidates.
Since the metal D53 is used in the same situation as the gate wiring, the same can be said for the metal A47.

As the metal B'48, for example, Ti, C
r, Ta, Mo, MoW, MoTa, Al, ITO, A
An alloy and a laminated structure of these metals are candidates.

As the metal B49, for example, Ti, Cr,
Candidates include Ta, Mo, MoW, MoTa, Al, ITO, and Al alloys, and a laminated structure of these metals. Since this metal B49 is used as a signal line,
Low resistance is desired. Therefore, it can be said that Al, a laminated structure using Al, an Al alloy, and the like are excellent. Further, when the metal B'48 is used, it is necessary to adopt an etching method which is not affected by the etching of the metal B49 or an etching method which is not affected.

As the upper type pixel electrode 65, for example, T
i, Cr, Ta, Mo, MoW, MoTa, Al, IT
O and the laminated structure of these metals are candidates. It is necessary to adopt a method in which the metal B49 is not affected when the upper pixel electrode 65 is etched, or an etching method in which the metal B49 is not affected.

As the metal C51 forming the common electrode 45, for example, Ti, Cr, Ta, Mo, MoW, MoT
a, Al, ITO, Al alloy, etc., and a laminated structure of these metals are candidates.

As the gate insulating film 23, for example, Si
O ₂ , SiNx, and SiOxNy can be considered, but a laminated structure of these may be used.

As the insulating film a55, for example, Si
O ₂ , SiNx, and SiOxNy can be considered, but a laminated structure of these may be used.

As the protective film 41, an inorganic insulating film, for example, SiNx, SiO ₂ , and an organic insulating film, for example, polyimides, BCB, HRC, black resist, and the like can be used.

As the interlayer insulating film 63, an inorganic insulating film, for example, SiNX, SiO ₂ , and an organic insulating film, for example, polyimides, BCB, HRC, black resist, and the like can be used. As the X-ray charge conversion film 43, a-Se, a-Si
Can be used.

The type of the TFT 1 is an inverted staggered inner etching stopper type as an example. This is an inverted staggered back channel cut type.
It may be of the type. The etching stopper type does not affect the channel portion when etching the channel portion of the TFT, so that the TFT characteristics hardly vary and is suitable for large arrays. The back channel cut type requires an etching stopper for the process. -Each type has the merit that the manufacturing cost is reduced because it is smaller than the type.

In the Si forming the TFT,
Here, a-Si (amorphous silicon) is used, but if it is formed of poly-Si (poly silicon),
Since the size of the TFT can be reduced, the effective area of the pixel can be increased, and the peripheral circuit can be formed on the same glass substrate. Therefore, there is an advantage that the manufacturing cost including the peripheral circuit is reduced.

Although the method of reading out the electric charges accumulated in the pixel by using the on / off of the TFT has been described above, the nondestructive readout method using the principle of the source follower is used in the non-destructive readout method. The number of
As a result, the number of power supply lines increases, which is a more effective means.

As described above, in the direct conversion type X-ray flat panel detector which is one of the X-ray imaging apparatuses of the medical X-ray diagnostic apparatus, the protection diode incorporated in the pixel as a countermeasure against the high voltage can reduce the leakage current. In addition, by adopting an object in which variation between pixels is small and increasing the number of power supply lines (plural lines) by forming the scanning line and the power supply line or the power supply line in different layers, the scanning line and the power supply line Alternatively, the yield can be prevented from deteriorating by eliminating a short circuit between power supply lines. Also, since the scanning line and the power supply line, or the power supply line between different layers, the line spacing can be narrowed,
The pixel electrode and the pixel capacitance can be formed larger.

(Sixth Embodiment) Next, a sixth embodiment will be described.

The example shown in FIG. 17 is functionally the same as the example shown in FIG. However, the protection diode incorporated in the pixel as a measure against high voltage adopts a device with less leakage current and less variation between pixels, and the power supply line (plurality) increased accordingly, the scanning line direction and the signal line In the direction, the scanning lines and the power supply lines, or the power supply lines are formed in different layers. This is to eliminate a short circuit between the scanning line and the power supply line or between the power supply lines, thereby preventing a decrease in yield when forming the power supply line. In addition, by setting the scanning line and the power supply line to be in different layers, the line interval can be reduced, so that the pixel electrode and the pixel capacitance can be formed larger.

Next, the configuration will be described with reference to a cross-sectional view (FIG. 18) of the sixth embodiment.

First, the power supply line 13 for the protection diode is formed of the metal D53 on the substrate. An insulating film a55 is formed thereon. However, the contact portion of the voltage supply line 25 (omitted in FIG. 18) and the power supply line 13
The insulating film a55 is removed from the contact portion between the protection diode 5 and the like. Metal A47 above it
Form the gate 17, the scanning line 9, the auxiliary electrode 11, the gate 21 of the protection diode TFT, and the power line 13 for the protection diode. On the upper layer, a gate insulating film 23 is formed. However, the gate insulating film 23 has been removed from the through-hole portion of the protection diode 5. In the upper layer, the pixel electrode 3 (metal B'48)
Are formed in the pixel except for the readout TFT 1 and the protection diode 5, and the readout TFT 1 and the protection diode 5 are formed.
Is formed on the gate insulating film 23 by a-Si2
7, SiNX29 for etching stopper, n ⁺ a-S
i31 is formed, and a source 3 serving as an electrode is formed thereon.
3 and the drain 35 are formed of another metal B49.
The metal B49 is used for the signal line 7 and the drawer pad 19.
(Omitted in FIG. 18), voltage supply line 25 (FIG. 1)
8 is omitted. ), The source 37 and the drain 39 of the protection diode TFT, and the power line 13 for the protection diode.
Etc. are also formed. Further, the pixel electrode 3 may be formed at the same time. However, in that case, the source 33 of the TFT 1, the source 37 of the protection diode TFT 5, and the pixel electrode 3
Are united. Thus, the TFT array is completed.

In the upper layer, a protective film 41, an X-ray charge conversion film 43, and a common electrode 45 made of metal C51 are formed, but are omitted in FIG. Medical X
The X-ray imaging device of the X-ray diagnostic apparatus is formed.

Although not shown in the drawings other than the example shown in FIG. 17, it is conceivable that the pixel electrode 3 is provided even above the power supply line 13. By doing so, the effective area of the pixel can be increased.

In addition to the example shown in FIG.
As shown in FIG.
In the third embodiment, the signal line formed in the same layer as the signal line was used.
As described above, the insulating film b57 may be placed on the metal B49 on which the signal line has been formed, and the metal E may be formed thereon.
As a result, a short circuit between the signal line 7 and the power supply line 13 does not occur, and it is possible to prevent a decrease in yield when the signal line 7 and the power supply line 13 are formed. Further, for example, the pixel electrode 3 may be formed of the metal E59. Although not shown, an interlayer insulating film 63 is provided on the TFT array described in the sixth embodiment, and the pixel electrode 3 contacts the pixel electrode 3 through a through hole of the interlayer insulating film 63 on the TFT array. By providing the upper type pixel electrode 65 having a potential, the aperture ratio (the ratio of the pixel electrode in one pixel) occupied by the increase in the number of power supply lines and the like can be reduced. It is very effective because the aperture ratio can always be made high regardless of the number.

The present invention is effective even if the number of TFTs for switching, the number of TFTs for protective diodes, the number of power supply lines, and the number of other wirings are other than those described in the above embodiments.

As the metal A47, for example, Ti, Cr,
Ta, Mo, MoW, MoTa, Al, ITO, Al alloy and the like, and a laminated structure of these metals are candidates.
Since this metal A47 is used as a gate wiring,
In particular, MoW and MoTa are excellent because they can be etched by tapering the gate portion of the TFT, and can be formed so that the gate insulating film 23 laminated thereover does not cause disconnection. I can say. In addition, in the case of an Al alloy, hillocks generated when a high-temperature process is performed can be prevented by using only Al, so that a gate line having a lower resistance can be obtained. It can be said that.

As the metal D53, for example, Ti, Cr,
Ta, Mo, MoW, MoTa, Al, ITO, Al alloy and the like, and a laminated structure of these metals are candidates.
Since the metal D53 is used in the same situation as the gate wiring, the same can be said for the metal A47.

As the metal B'48, for example, Ti, C
r, Ta, Mo, MoW, MoTa, Al, ITO, A
An alloy and a laminated structure of these metals are candidates.

As the metal B49, for example, Ti, Cr,
Candidates include Ta, Mo, MoW, MoTa, Al, ITO, and Al alloys, and a laminated structure of these metals. Since this metal B49 is used as a signal line,
Low resistance is desired. Therefore, it can be said that Al, a laminated structure using Al, an Al alloy, and the like are excellent. Further, when the metal B'48 is used, it is necessary to adopt an etching method which is not affected by the etching of the metal B49 or an etching method which is not affected.

As the metal E59, for example, Ti, Cr,
Candidates include Ta, Mo, MoW, MoTa, Al, ITO, and Al alloys, and a laminated structure of these metals. However, at the time of etching the metal E59, it is necessary to adopt a method in which the metal B'48 and the metal B49 are not affected, or an etching method in which the metal B'48 and the metal B49 are not affected.

As the upper type pixel electrode 65, for example, T
i, Cr, Ta, Mo, MoW, MoTa, Al, IT
O and the laminated structure of these metals are candidates. It is necessary to adopt a method in which the metal B49 is not affected when the upper pixel electrode 65 is etched, or an etching method in which the metal B49 is not affected.

As the metal C51 forming the common electrode 45, for example, Ti, Cr, Ta, Mo, MoW, MoT
a, Al, ITO, Al alloy, etc., and a laminated structure of these metals are candidates.

As the gate insulating film 23, for example, Si
O ₂ , SiNX, and SiOXNy are considered, but a laminated structure of these may be used.

As the insulating film a55, for example, Si
O ₂ , SiNX, and SiOxNy are considered, but a laminated structure of these may be used.

As the insulating film b57, an inorganic insulating film such as SiNX, SiO ₂ and an organic insulating film such as polyimides, BCB, HRC, and black resist can be used.

As the protective film 41, an inorganic insulating film, for example, SiNx, SiO ₂ , and an organic insulating film, for example, polyimides, BCB, HRC, black resist, and the like can be used.

As the interlayer insulating film 63, an inorganic insulating film, for example, SiNX, SiO ₂ , and an organic insulating film, for example, polyimides, BCB, HRC, black resist, and the like can be used. As the X-ray charge conversion film 43, a-Se, a-Si
Can be used.

The type of the TFT 1 is an inverted staggered inner etching stopper type as an example. This is an inverted staggered back channel cut type.
It may be of the type. The etching stopper type does not affect the channel portion when etching the channel portion of the TFT, so that the TFT characteristics hardly vary and is suitable for large arrays. The back channel cut type requires an etching stopper for the process. -Each type has the merit that the manufacturing cost is reduced because it is smaller than the type.

In the case of Si forming a TFT,
Here, a-Si (amorphous silicon) is used, but if it is formed of poly-Si (poly silicon),
Since the size of the TFT can be reduced, the effective area of the pixel can be increased, and the peripheral circuit can be formed on the same glass substrate. Therefore, there is an advantage that the manufacturing cost including the peripheral circuit is reduced.

Although the method of reading out the charges accumulated in the pixel by using the ON / OFF of the TFT has been described above, the non-destructive read-out method using the principle of the source follower uses the TFT in the pixel. The number of
As a result, the number of power supply lines increases, which is a more effective means.

As described above, in the direct conversion type X-ray flat panel detector which is one of the X-ray imaging apparatuses of the medical X-ray diagnostic apparatus, the protection diode incorporated in the pixel as a measure against the high voltage can reduce the leakage current. In addition, by adopting an object in which variation between pixels is small and increasing the number of power supply lines (plural lines) by forming the scanning line and the power supply line or the power supply line in different layers, the scanning line and the power supply line Between them, or between power supply lines, thereby preventing the yield from deteriorating. In addition, by making the scanning line and the power supply line or between the power supply lines in different layers, the line interval can be narrowed, so that the pixel electrode and the pixel capacitance can be made larger.

(Seventh Embodiment) Next, a seventh embodiment will be described.

The example shown in FIG. 21 is functionally the same as the example shown in FIG. However, the power line 13 for the protection diode is
Instead of being provided in the signal line direction at the time of signal line formation, they are formed in the scanning line direction on a layer different from the scanning lines in the same manner as the scanning lines. As described above, when the power supply line is provided in two layers below the scanning line, the capacitance in the pixel can be increased by utilizing the insulating film introduced between the layers.

Next, the configuration will be described with reference to a cross-sectional view (FIG. 22) of the seventh embodiment.

First, the metal D53 forms the power line 13 for the protection diode and the lower pixel electrode 61 on the substrate.
An insulating film a55 is formed thereon. However,
The insulating film a55 includes a contact portion of the voltage supply line 25 (omitted in FIG. 22), a contact portion between the power supply line 13 and the protection diode 5, a contact portion between the pixel electrode 3 and the lower pixel electrode 61, and the like. Has been removed. The metal A47 in the upper layer forms the gate 17 of the TFT, the scanning line 9, the auxiliary electrode 11, and the gate 21 of the protection diode TFT. On the upper layer, a gate insulating film 23 is formed. However, the gate insulating film 23 has been removed from the through-hole portion of the protection diode 5. On the upper layer, the pixel electrode 3 (metal B'48) has a readout T
Formed in the pixel excluding the FT1 and the protection diode 5,
In the read TFT 1 and the protection diode 5, a-Si 27, an etching stopper SiNx 29, and n ⁺ a-Si 31 are formed on the gate insulating film 23, and the source 33 and the drain 3 serving as electrodes are formed thereon.
5 is formed of another metal B49. This metal B49
Are also formed with a signal line 7, a drawing pad 19 (omitted in FIG. 22), a voltage supply line 25 (omitted in FIG. 22), a source 37 and a drain 39 of a protection diode TFT. ing. Further, the pixel electrode 3 may be formed at the same time. However, in this case, the source 33 of the TFT 1, the source 37 of the protection diode TFT 5, and the pixel electrode 3 are integrated. Thus, the TFT array is completed. On the upper layer, a protective film 41, an X-ray charge conversion film 43, and a common electrode 45 made of metal C51 are formed, but are omitted in FIG. Medical X
The X-ray imaging device of the X-ray diagnostic apparatus is formed.

Except for the example shown in FIG. 21, the pixel electrode 3 is brought up to above the power supply line 13 (not shown), or the protection diode power supply line 13 is provided below the scanning line 9 (see FIG. 21). May be omitted). By doing so, the effective area of the pixel can be increased.

In addition to the example shown in FIG. 21, a power supply line 13 for protection diode formed of metal D53 may be provided in the direction of signal line 7 (not shown). By doing so, not only can the effective area of the pixel be increased, but also the parasitic capacitance on the signal line can be reduced.

In FIG. 21, the protection diode is
An example in which one TFT is used has been given, but two or more TFTs are arranged in series to reduce the leakage current from the protection diode, and the TFT for the protection diode has a low leakage countermeasure. Is also conceivable.

Further, the present invention can be applied to all the examples described in the fourth, fifth, and sixth embodiments.
3 increases and the space occupied by the pixel electrode 3 and the auxiliary electrode 11 becomes narrower, so that Cst15 becomes smaller, so that the effect becomes larger.

Although not shown in the figure, an interlayer insulating film 63 is provided on the TFT array described in the seventh embodiment, and the pixel electrode 3 is brought into contact with the pixel electrode 3 through a through hole in the interlayer insulating film 63. By providing the upper type pixel electrode 65 having the same electric potential, the aperture ratio (the ratio of the pixel electrode in one pixel) occupied by the increase in the number of power supply lines is reduced by the power supply line in one pixel or the like. This is very effective because the aperture ratio can always be increased regardless of the number of TFTs.

As the metal A47, for example, Ti, Cr,
Ta, Mo, MoW, MoTa, Al, ITO, Al alloy and the like, and a laminated structure of these metals are candidates.
Since this metal A47 is used as a gate wiring,
In particular, MoW and MoTa are excellent because they can be etched by tapering the gate portion of the TFT, and can be formed so that the gate insulating film 23 laminated thereover does not cause disconnection. It can be said that. In addition, in the case of an Al alloy, hillocks generated when a high-temperature process is performed can be prevented by using only Al, so that a gate line having a lower resistance can be obtained. It can be said that.

As the metal D53, for example, Ti, Cr,
Ta, Mo, MoW, MoTa, Al, ITO, Al alloy and the like, and a laminated structure of these metals are candidates.
Since the metal D53 is used in the same situation as the gate wiring, the same can be said for the metal A47.

As the metal B'48, for example, Ti, C
r, Ta, Mo, MoW, MoTa, Al, ITO, A
An alloy and a laminated structure of these metals are candidates.

As the metal B49, for example, Ti, Cr,
Candidates include Ta, Mo, MoW, MoTa, Al, ITO, and Al alloys, and a laminated structure of these metals. Since this metal B49 is used as a signal line,
Low resistance is desired. Therefore, it can be said that Al, a laminated structure using Al, an Al alloy, and the like are excellent. Further, when the metal B'48 is used, it is necessary to adopt an etching method which is not affected by the etching of the metal B49 or an etching method which is not affected.

As the upper type pixel electrode 65, for example, T
i, Cr, Ta, Mo, MoW, MoTa, Al, IT
O and the laminated structure of these metals are candidates. It is necessary to adopt a method in which the metal B49 is not affected when the upper pixel electrode 65 is etched, or an etching method in which the metal B49 is not affected.

As the metal C51 forming the common electrode 45, for example, Ti, Cr, Ta, Mo, MoW, MoT
a, Al, ITO, Al alloy, etc., and a laminated structure of these metals are candidates.

As the gate insulating film 23, for example, Si
O ₂ , SiNx, and SiOxNy can be considered, but a laminated structure of these may be used.

As the insulating film a55, for example, Si
O ₂ , SiNx, and SiOxNy can be considered, but a laminated structure of these may be used.

As the protective film 41, an inorganic insulating film, for example, SiNx, SiO ₂ , and an organic insulating film, for example, polyimides, BCB, HRC, black resist, and the like can be used.

As the interlayer insulating film 63, an inorganic insulating film, for example, SINX, SiO ₂ , and an organic insulating film, for example, polyimides, BCB, HRC, black resist, and the like can be used. As the X-ray charge conversion film 43, a-Se, a-Si
Can be used.

The type of the TFT 1 has been described as an example of an inverted staggered inner etching stopper type. This is an inverted staggered back channel cut type.
It may be of the type.

In the etching stopper type, TF
Since the channel portion is not corroded at the time of etching the channel portion of T, variation in TFT characteristics hardly occurs and is suitable for a large array, and the back channel cut type requires fewer steps than the etching stopper type. Therefore, there is an advantage that the manufacturing cost is reduced.

In the Si forming the TFT,
Here, a-Si (amorphous silicon) is used, but if it is formed of poly-Si (poly silicon),
Since the size of the TFT can be reduced, the effective area of the pixel can be increased, and the peripheral circuit can be formed on the same glass substrate. Therefore, there is an advantage that the manufacturing cost including the peripheral circuit is reduced.

Although the method of reading out the charge accumulated in the pixel by using ON / OFF of the TFT has been described above, the non-destructive read-out method using the source follower principle has been described. The number of
As a result, the number of power supply lines increases, which is a more effective means.

As described above, in the direct conversion type X-ray flat panel detector which is one of the X-ray imaging apparatuses of the medical X-ray diagnostic apparatus, the power supply line of the protection diode incorporated in the pixel as a measure against the high voltage is changed to the scanning line. When two layers are provided in the lower layer, the capacitance in the pixel can be increased by utilizing the insulating film introduced between the layers.

By providing these means, the direct conversion type X-ray, which is one of the X-ray imaging apparatuses of the medical X-ray diagnostic apparatus, is provided.
In the line flat detector, the bias line for the protection diode used as a measure against the high voltage of the pixel is provided by reducing the occurrence of the parasitic capacitance to the signal line or increasing the pixel capacitance without significantly lowering the yield. Can be formed.

In the direct conversion type X-ray flat panel detector,
As a measure against a high voltage that can be applied to the read-out TFT, the use of a protective diode enables a fluoroscopic mode, and a protective TF is required to measure a sufficiently weak signal.
It is necessary to reduce the off current of T and its variation. According to the present invention, the leakage current of the protection TFT and its fluctuation can be reduced. In addition, application of an excessive voltage to the protection diode can be prevented.

(Eighth Embodiment) Hereinafter, an eighth embodiment of the present invention will be described.
The function of the device according to the embodiment will be described.

The direct conversion type X-ray detector shown in FIG.
Reference numeral 10 denotes an a-Si TFT 1 and a photoelectric conversion film (for example, a-S
e) 202 and pixel capacity (hereinafter referred to as Cst) 203
The pixels 210 are arranged in an array (hereinafter, referred to as a TFT array) in which several hundred to several thousand pixels are arranged on each side in the vertical and horizontal directions. A bias voltage is applied to the photoelectric conversion film 202 by a power supply 208. The a-Si TFT 1 is connected to the signal line 206 and the scanning line 207, and is turned on and off by the scanning line driving circuit 211. Signal line 206
Is connected to a signal detection amplifier 212 through a changeover switch. The protection TFT 204 is a power supply 2
13 biased. X-ray charge conversion film 202
When the electric charge generated by the incidence of X-rays accumulates in the Cst 203 and reaches a certain voltage that does not cause dielectric breakdown of the TFT 201, the electric charge flows out of the pixel from the protection diode 204, and the readout TFT 201
And Cst 203 are not applied with a high voltage. The outflow path of the electric charge at this time is the power supply line 209 for the diode,
By setting the potential of the power supply line 209 set by the power supply 213, the voltage at which charge starts flowing out of the protection diode 204 is changed. By scanning the scanning line 207, the electric charge accumulated in the pixel is changed to the T value of each pixel on the scanning line.
The FT is turned on and the signal flows through the signal line 206. The charge that has flowed out is transferred to the amplifier 212.

As shown in the pixel plan view of FIG. 29, the pixel circuit includes a reading TFT 201, a pixel electrode 261, a protection diode 204, a signal readout line (signal line) 207, a gate line (scanning line) 207, and an auxiliary capacitance electrode 205. , And a protection diode power supply line 209. However, in FIG. 29, the protective film 241, the common electrode 245, the X-ray charge conversion film 243, and those disposed outside the pixel are omitted. As an example of the function, the pixel capacitance Cst203
Is composed of a pixel electrode 261 and an auxiliary capacitance electrode 205.

Next, a sectional view of the eighth embodiment (FIG. 30)
The configuration will be described below.

First, on a glass substrate, metal A17 is
FT gate 217, scanning line 207, lead-out pad 219, auxiliary capacitance electrode 205, TFT for protection diode
Gate 221 is formed. A gate insulating film 223 is formed thereover. However, the gate insulating film 223 is removed from the extraction pad portion 219, the contact portion of the voltage supply line 225, and the through hole portion of the protection diode 204. Read TFT 20
1 and the protection diode 204, a-Si 227 and SiNx 229 for an etching stopper were formed on the gate insulating film 223. Next, SiH ₄ , H
_2, by plasma CVD of a mixed gas of PH ₃ n ⁺ a-
Si (N) 231 was formed. A source 233 and a drain 235, which are electrodes of the TFT, are formed thereon with another metal B49. Using this metal B59 as a mask, n ⁺ a
-Etch Si. This metal B49 is used for the signal line 2
07, a protection diode power supply line 213, a drawer pad 219 (omitted in FIG. 30), a voltage supply line 2
25 (omitted in FIG. 30), the source 237 and the drain 239 of the protection diode TFT are also formed. An insulating film 241 is formed thereon. An opening is formed in the insulating film at the contact portion between the TFT 201 and the source of the protection diode TFT. On this, the pixel electrode 203 is formed so as to cover the protection diode. An X-ray charge conversion film 43 and a common electrode 45 made of metal C51 are formed on the upper layer, but are omitted in FIG. With these configurations, an X-ray imaging apparatus of a medical X-ray diagnostic apparatus is formed.

Next, the production method will be described in detail. An eighth embodiment will be described with reference to FIG. On a glass substrate 201, MoTa, Ta, TaN, Ta / TaNx. Al, Al
An alloy, Cu, MoW, etc. are deposited to a thickness of 3000 A (angstrom), etched, and
17, the pattern of the Cs line 221 and the address line 217 were formed. Next, the insulating film 223 is formed by a plasma CVD method.
SiOx having a thickness of 3000A (angstrom), SiNx having a thickness of 500A (angstrom), undoped a-Si227 having a thickness of 1000A (angstrom), and a stopper SiNx having a thickness of 2000A.
(Angstrom) layer 229. The stopper SiNx of the TFT portion is patterned along with the gate by using backside exposure. After depositing n + a-Si 531 to a thickness of 500 A (angstrom), the n +
The a-Si and a-Si were etched to form a-Si islands. Next, a contact hole was formed by etching the SiNx / SiOx in the contact portion. On this, Mo was sputtered to 500 A (angstrom) / A13500A (angstrom) / Mo500A (angstrom) or Mo to a thickness of 2000 A (angstrom) to form a signal line 207. Next, SiNx is applied to a thickness of 2
The protective film 241 was formed by 000 A (angstrom). On top of this, a protective film 241-
1 was formed to 1 to 3 μm, preferably 2 μm. Then TF
After forming a contact hole to T201 and the source electrode of the protection diode TFT, the thickness of the ITO is 1000A.
(Angstrom) film was used to form the pixel electrode 261. At this time, the ITO pixel was formed so as to cover the protection diode in a plane. Next, a pin layer of Se was deposited to form an X-ray photosensitive layer. Next, the upper electrode is Al1000
A (Angstrom).

Finally, the pixel was connected to a driving circuit around the pixel.

FIG. 31 compares the characteristic B of the pixel circuit according to the present invention with the conventional characteristic A. The potential of the pixel is read out to an external amplifier by a readout pulse applied to the gate of the TFT, and becomes a set voltage (0 V). When the read pulse is turned off, the TFT is turned off and separated. At this time, the Se photoreceptor has a low resistance due to the irradiated X-rays, and approaches the voltage (5 kV) applied to the electrode on Se. At this time, if the voltage exceeds the set voltage (10 V) of the protection diode, the protection diode TFT is turned on, and the pixel electrode potential is fixed at the set voltage. At this time, if the insulating film between the pixel electrode and the protection diode is thin and the capacitance is large, electrons are induced in the a-Si of the protection transistor by the pixel potential, and the resistance of the protection diode decreases. In this case, as shown in the figure, the pixel potential approaches the protection voltage level, causing an error. In contrast, when a thick insulating film is formed as in the present invention, capacitive coupling can be prevented and an accurate potential can be maintained. On the other hand, when the insulating film is thin or an insulating film having a large dielectric constant (5 or more) is used, even if the light intensity is lower than the white level, the light becomes white and the dynamic range becomes small, so that an accurate image cannot be displayed.

Similar results were obtained when other protection circuits were used. FIG. 32 shows the case of a series protection diode, and FIG. 33 shows the case of a current control type protection diode. Both can achieve the same effect.

In the present invention, the protection transistor is provided below the pixel. However, if the protection transistor is provided between the pixels, a problem of dielectric breakdown occurs. In the direct conversion method, a high voltage of about 5 to 10 kV is applied to the upper electrode of Se. This high voltage has a capacity of Se (500 μm) and a resin protection film (2
μm) and the capacity of the gate oxide film (3000 A), and a high voltage of about 130 V is applied between the sweeping electrode of the protection diode and the gate to cause dielectric breakdown of the gate insulating film of the diode or TFT. Of Vth, and the characteristics are degraded. When the Se resistance further decreases due to X-rays, most of the high voltage is applied to the drain electrode of the protection diode, so an overvoltage is applied between the gate electrode and the gate electrode to cause dielectric breakdown. cause.

On the other hand, when the protection transistor is formed below the pixel electrode, the protection transistor is electrostatically shielded by the pixel electrode, so that a high voltage force is not applied.

The entirety of the protection transistor or at least T
Preferably, the channel portion of the FT is formed below the pixel electrode. When there are a plurality of protection TFTs, it is effective if at least one TFT is below the pixel electrode. When there are a plurality of insulating films, the protective TF is provided under the lowermost insulating film.
It is preferable to arrange T.

It is preferable that the bias line for the protection TFT is also arranged below the pixel electrode, so that the dielectric breakdown due to the high voltage of the upper and lower electrodes of the photosensitive film and the unevenness in the screen due to the change of the bias voltage can be prevented.

As the metal A47, for example, Ti, Cr,
Ta, Mo, MoW, MoTa, Al, ITO, Al alloy and the like, and a laminated structure of these metals are candidates.
Since this metal A47 is used as a gate wiring,
In particular, MoW and MoTa are excellent because they can be etched by tapering the gate portion of the TFT, and can be formed so that the gate insulating film 223 stacked thereover does not cause disconnection. I can say.

As the metal B'48, 49, for example, T
i, Cr, Ta, Mo, MoW, MoTa, Al, IT
O, Al alloys, and the laminated structure of these metals are candidates. For example, MoAlMo is good. This metal B49
In order to be used as a signal line, it is particularly desired to lower the resistance. Therefore, Al or a laminated structure using Al, A
It can be said that alloy 1 is excellent. Further, when the metal B'48 is used, it is necessary to adopt an etching method which is not affected by the etching of the metal B49 or an etching method which is not affected.

As the metal C51 forming the common electrode 45, for example, Ti, Cr, Ta, Mo, MoW, MoT
a, Al, ITO, Al alloy, etc., and a laminated structure of these metals are candidates. Alternatively, it is preferable to use InZnO or amorphous ITO because etching is performed.

As the gut insulating film 223, for example, S
Although iO2, SiNx, and SiOxNy are conceivable, a laminated structure of these may be used.

As the protective film insulating film 241, an inorganic insulating film, for example, SiNx, SiO ₂ , and an organic insulating film, for example, polyimides (ε3.3 withstand voltage 300 V / mm), BCB
(Ε2.7 withstand voltage 400 V / mm), an acrylic photosensitive resin Optmer PC (ε3.2), a black resist or the like may be used, and these may be laminated as needed. Fluorocarbon resins such as Cytop are effective because of their small relative dielectric constant (2.1). When the protection diode is formed below the pixel electrode, the thickness may be 2 to 10 μm. In order to eliminate the effect of the protection diode due to the pixel potential, the voltage applied to the protection diode needs to be about 1/10 of the pixel potential (about 10 V). Should be 2 μm or more, more preferably 4 μm or more. If the thickness is too large, it is preferably 15 μm or less because the pixel electrode is cut at a stepped portion. When a protection diode is provided outside or between pixel electrodes, it needs to be about 10 to 15 μm.

As the X-ray charge conversion film 243, a-S
e, a-Si, a-Te, PbI ₂ may be used.

The type of the TFT 1 has been described as an example of an inverted staggered inner etching stopper type, which is an inverted staggered back channel cut type.
It may be of the type. The etching stopper type does not affect the channel portion when etching the channel portion of the TFT, so that the TFT characteristics hardly vary and is suitable for large arrays. The back channel cut type requires an etching stopper for the process. -Each type has the merit that the manufacturing cost is reduced because it is smaller than the type.

In the Si forming the TFT,
Here, a-Si (amorphous silicon) is used, but if it is formed of poly-Si (poly silicon),
Since the size of the TFT can be reduced, the effective area of the pixel can be increased, and the peripheral circuit can be formed on the same glass substrate. Therefore, there is an advantage that the manufacturing cost including the peripheral circuit is reduced.

As described above, in the direct conversion type X-ray flat panel detector which is one of the X-ray imaging apparatuses of the medical X-ray diagnostic apparatus, the protection insulating film is provided between the protection diode for high voltage measures and the pixel electrode. With this arrangement, occurrence of an error in the pixel potential can be prevented or reduced. For this reason, it became strong against noise, and the image quality was further improved. As a result, the X-ray intensity can be reduced and the device can be used in a state more safe for the human body.

By having these means, the direct conversion type X-ray, which is one of the X-ray imaging apparatuses of the medical X-ray diagnostic apparatus, is provided.
In the line flat detector, by providing a protective insulating film between the protective diode for high voltage measures and the pixel electrode, it is possible to prevent and reduce the occurrence of errors in the pixel potential. For this reason, it became strong against noise, and the image quality was further improved. This gives X
It can be used in a state safer for the human body by weakening the line strength.

(Ninth Embodiment) The ninth embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 34 is a diagram showing one pixel in a TFT array portion of an imaging device according to the ninth embodiment of the present invention. In this embodiment, a pixel is provided with a protection diode TFT2 for preventing dielectric breakdown when a high voltage is applied to a pixel electrode, in addition to the signal charge readout switch TFT1.

The signal charge readout switch TFT1 is
The gate electrode is on the scanning line G1, and the source electrode is on the signal line S1.
In addition, a drain electrode is connected to the pixel capacitance electrode Cs (GND) and a pixel electrode (not shown). The signal charge readout switch TFT1 is turned on when the scanning line G1 becomes "H" level (for example, 20 [V]), and has a function of transferring the charge stored in the pixel capacitance to a detector (not shown). doing.

The protection diode TFT2 has a gate electrode and a drain electrode both connected to a pixel electrode (not shown), and a source electrode connected to a bias line B1. The bias line B1 is kept at a constant potential Vb and controls the breakdown voltage of the protection diode TFT2. When the pixel electrode rises to an arbitrary voltage or more (for example, 10 V or more), the protection diode TFT2 is turned on, and the signal charge is released to the bias line B1. This makes it possible to control so that a voltage equal to or higher than a certain value is not applied to the pixel electrode.

In this embodiment, as shown in FIGS. 34 and 35, a plurality of TFTs in a pixel, that is, the channel direction CH1 of the signal charge readout switch TFT1 and the channel direction CH2 of the protection diode TFT2 are parallel to each other. A feature is that transistors are arranged.

FIGS. 36 and 37 show T in one pixel when a mask position shift occurs during the formation of the source electrode and the drain electrode.
3 shows the shape of an FT. A solid line indicates a desired TFT shape, and a dotted line indicates a TFT shape that can be actually formed due to a mask position shift. FIG. 36 shows that the mask is Δχ parallel to the channel direction.
FIG. 37 shows a case in which it is shifted by Δy perpendicular to the channel direction. If the mask is displaced in parallel with the channel direction, a difference occurs in the length of the source electrode and the drain electrode. Therefore, when the TFT characteristics are viewed, effects such as a shift in Vth and an increase in off-state current appear. However, since the source electrode and the drain electrode are displaced by the same amount in every TFT in the pixel, the characteristics (off-state current, Vth, etc.) of the TFT in the pixel can be maintained at the same level.
Similarly, if the mask is displaced perpendicularly to the channel direction, the channel width changes, causing an increase in on-resistance. However, also in this case, there is no variation in TFT characteristics because the shift amount of the TFT in the pixel is the same.

That is, as shown in FIGS. 36 and 37,
Even if a mask shift occurs during the TFT array manufacturing process, by making the channel directions parallel, it is possible to form a plurality of TFTs in a pixel equally.
Therefore, variation in characteristics of a plurality of TFTs in a pixel can be suppressed, and image quality deterioration such as an increase in noise can be suppressed.

FIG. 38 is a diagram in which the pixels shown in this embodiment are applied to the entire TFT array. By applying the pixel structure shown in FIG. 34 to all the pixels in the pixel region, variation between pixels is reduced, and good image quality can be obtained.

Although the source electrode of the protection diode TFT2 is connected to the bias line B1 in FIGS. 34 and 38, the same effect can be obtained by connecting this to the pixel capacitance electrode Cs (eg, GND) as shown in FIG. Can be obtained. FIG.
The nine pixels may be applied to the entire TFT array as shown in FIG. Further, in FIGS. 34 and 38, the signal charge readout switch TFT1 is constituted by one TFT, but a plurality of signal charge readout switches TFT1 may be connected in series. Similarly, in FIGS. 34 and 38, the protection diode TFT2 is constituted by one TFT. However, as shown in FIG. 40, a plurality of TFTs may be connected in series or in parallel. When a protection diode is composed of a plurality of TFTs, the constitutions (1) and (3) in which the gate electrode of each TFT is common, the diodes (2), (4), and (1) are used in each TFT Any combination of the configurations of (4) may be used.

(Tenth Embodiment) FIG. 41 is a view showing one pixel of a TFT array portion of an imaging device according to a tenth embodiment of the present invention. The basic configuration, operation, and the like are the same as those in the ninth embodiment. Corresponding components have the same reference characters allotted, and detailed description thereof will not be repeated.

In this embodiment, in addition to the signal charge readout switch TFT1, a protection diode TFT2 for preventing dielectric breakdown in a pixel when a high voltage is applied to the pixel electrode, and a bias circuit TFT for controlling a breakdown voltage of the protection diode, are provided.
3 shows the case of a pixel in which a TFT 4 is provided.

The signal charge readout switch TFT1 is
As in the first embodiment, the signal is turned on / off by the signal of the scanning line G1, and the charge stored in the pixel electrode is transferred to a detection amplifier (not shown).

The protection diode TFT2 is a TFT which controls so that a voltage equal to or higher than a certain value is not applied to the pixel electrode as in the first embodiment. The drain electrode of the TFT2 is connected to the pixel electrode, the source electrode is connected to the Cs line, and the gate electrode is connected to the bias circuits TFT3 and TFT4. The output Vout of the bias circuits TFT3 and TFT4 outputs a signal biased by Va−Vb with respect to the input signal (here, the pixel electrode potential).
Can be controlled.

In this embodiment, as shown in FIG. 41, a plurality of TFTs in a pixel, that is, a channel direction CH1 of a signal charge readout switch TFT1 and a protection diode T1.
FT2 channel direction CH2 and bias circuit TFT3,
The feature is that the thin film transistors are arranged such that the channel directions CH3 and CH4 of the TFT4 are parallel.

By adopting the structure of this embodiment, it is possible to form the plurality of TFTs in the pixel equally even if the mask is misaligned as in the ninth embodiment. Therefore, variation in characteristics of a plurality of TFTs in a pixel can be suppressed, and image quality deterioration such as an increase in noise can be suppressed. Also, bias circuit TFT3, TF
T4 affects the breakdown voltage of the protection diode TFT2 because the deviation of Vth affects the output Vout. However, the configuration of the present embodiment makes it possible to equalize Vth of the bias circuit, and to set a desired breakdown voltage. Can be set. FIG. 43 is a diagram in which the pixels described in this embodiment are applied to the entire TFT array. By applying the pixel structure shown in FIG. 41 to all the pixels in the pixel region, variation between the pixels is reduced, and good image quality can be obtained.

In FIGS. 41 and 43, the source electrode of the protection diode TFT2 is connected to the Cs line.
The same effect can be obtained by arranging and connecting another bias line B1. In FIGS. 41 and 43, the signal charge readout switch TFT1 is constituted by one TFT, but a plurality of signal charge readout switch TFTs 1 may be connected in series. Similarly, in FIGS. 41 and 43, the protection diode TFT2 is replaced by one TFT.
However, as in the ninth embodiment, a plurality of TFTs may be connected in series or in parallel as shown in FIG. When a protection diode is composed of a plurality of TFTs, the constitutions (1) and (3) in which the gate electrode of each TFT is common, the diodes (2), (4), and (1) are used in each TFT Any combination of the configurations of (4) may be used.

(Eleventh Embodiment) FIG. 44 is a view showing one pixel of a TFT array portion of an imaging device according to an eleventh embodiment of the present invention. The basic configuration, operation, and the like are the same as those in the ninth embodiment. Corresponding components have the same reference characters allotted, and detailed description thereof will not be repeated.

In this embodiment, the electric charge accumulated in the pixel is converted into a voltage and output. AMI (Amplified
A pixel having a TFT structure called a MOS imager (MOSImager) system and further having a protection diode TFT2 for preventing dielectric breakdown in the pixel when a high voltage is applied to the pixel electrode is shown.

In the AMI system, a bias T is connected to the signal line S1.
The drain electrode of the FTB is connected, and a bias voltage is applied to the gate electrode and the source electrode to apply a bias voltage to the gate. The source-to-source voltage Vgs is fixed at a constant potential. In the pixel portion, the source electrode of the output TFTO is connected to the signal line S1, the gate electrode is connected to the pixel electrode, and the drain electrode is connected to the selection TFTS. A scanning line G1 is applied to the gate electrode of the TFTS, and a bias voltage is applied to the drain electrode. Further, a reset TFT R is connected to the pixel electrode, and a gate electrode of the TFT R is connected to the bias line R1. Scan line G1 is "H"
Is turned on, and is selected so that the potential of the pixel is output. The electric charge accumulated in the pixel electrode by the TFTB and TFTO is a voltage (pixel electrode potential−Vg).
s) and output. After outputting the pixel signal, T
The FTR is turned on, and the electric charge stored in the pixel electrode is released to reset the pixel potential.

The protection diode TFT2 has a gate electrode and a drain electrode both connected to a pixel electrode (not shown), and a source electrode connected to a bias line B1. The bias line B1 is maintained at a constant potential Vb and controls the breakdown voltage of the diode TFT2. When the pixel electrode rises to an arbitrary voltage or more (for example, 10 [V] or more), the protection diode TFT2 is turned on, and the signal charge is transferred to the bias line B.
Escape to 1 This makes it possible to control so that a voltage equal to or higher than a certain value is not applied to the pixel electrode.

In this embodiment, as shown in FIGS. 44 and 45, a thin film transistor (TFT,
Channel direction (CH) of TFTS, TFTR, TFT2)
O, CHS. CHR, CH2),
Channel direction C of bias thin film transistor TFTB
It is characterized in that it is arranged in parallel with HB.

With the structure of this embodiment, even if a mask misalignment occurs as in the ninth embodiment, a plurality of TFTs in a pixel and a bias TFT connected to a signal line are provided.
It becomes possible to form the shape of the FT equally. Therefore, it is possible to suppress variations in the characteristics of a plurality of TFTs and bias TFTs in a pixel, and to suppress deterioration in image quality such as an increase in noise. TFTB, TFTO
Although the shift of Vth affects the pixel signal output, the configuration of the present embodiment makes it possible to equalize Vth of TFTB and TFTO, and no variation in output occurs. Also, regarding the long-term shift of Vth, TFTB and TFT
Since O shows the same tendency, it is possible to detect an image efficiently without the trouble of adjusting. In addition, since the reset TFT R and the protection diode TFT2 can be formed in the same shape, variation in off current can be reduced.

FIG. 46 is a diagram in which the pixels shown in this embodiment are applied to the entire TFT array. By applying the pixel structure shown in FIG. 44 to all the pixels in the pixel region, variation between the pixels is reduced, and good image quality can be obtained.

Although the source electrode bias line B1 of the protection diode TFT2 is connected in FIGS. 44 and 46, the same effect can be obtained by connecting it to the pixel capacitor electrode Cs (for example, GND) as in the protection diode TFT2 in FIG. can get. In FIGS. 44 and 46, the signal charge readout switch TFT1 is constituted by one TFT, but a plurality of signal charge readout switches may be connected in series. Similarly, in FIGS. 44 and 46, the protection diode TFT2 is constituted by one TFT. However, as in the ninth embodiment, as shown in FIG.
A plurality of Ts may be connected in series or in parallel. When a protection diode is composed of a plurality of TFTs, each TFT
(1) and (3) using a common gate electrode, (2) and (4) using a diode for each TFT, or any combination of the configurations (1) to (4). .

(Twelfth Embodiment) FIG. 47 shows a part of a TFT array portion of an imaging device according to a twelfth embodiment of the present invention.
FIG. 3 is a diagram illustrating pixels. The basic configuration, operation, and the like are the same as those in the eleventh embodiment. Corresponding components have the same reference characters allotted, and detailed description thereof will not be repeated.

In this embodiment, an AMI (Amplified M) that converts a charge accumulated in a pixel into a voltage and outputs the voltage.
It has a TFT structure called an OS Imager system, and has a protection diode TFT2 for preventing dielectric breakdown in a pixel when a high voltage is applied to a pixel electrode, and bias circuits TFT3 and TFT4 for controlling a breakdown voltage of the protection diode. The figure shows the case of a certain pixel.

By adopting the structure of this embodiment, even if the mask is misaligned as in the ninth embodiment, the shapes of the plurality of TFTs in the pixel and the bias TFT connected to the signal line can be changed. It is possible to form them equally. Therefore, it is possible to suppress variations in the characteristics of a plurality of TFTs and bias TFTs in a pixel, and to suppress deterioration in image quality such as an increase in noise. TFTB, TFT
In the case of O, the shift of Vth affects the pixel signal output. However, the configuration of the present embodiment makes it possible to equalize Vth of TFTB and TFTO, and no variation in output occurs. Also, regarding the long-term shift of Vth, TFTB and TF
Since TO shows the same tendency, an image can be detected efficiently without the need for adjustment. Also bias circuit TFT
3. In the TFT 4, the shift of Vth affects the output Vout, which affects the breakdown voltage of the protection diode TFT2.
h can be made equal, and the breakdown voltage can be set to a desired value.

FIG. 48 is a diagram in which the pixel shown in this embodiment is applied to the entire TFT array. By applying the pixel structure shown in FIG. 47 to all the pixels in the pixel region, variation between the pixels is reduced, and good image quality can be obtained.

Although the source electrode of the protection diode TFT2 is connected to the Cs line in FIGS. 47 and 48, the same effect can be obtained by arranging and connecting another bias line B1. Further, in FIGS. 47 and 48, the signal charge readout switch TFT1 is constituted by one TFT, but a plurality of switches may be connected in series. Similarly, in FIGS. 47 and 48, the protection diode TFT2 is constituted by one TFT. However, as in the ninth embodiment, a plurality of TFTs are connected in series or in parallel as shown in FIG. It does not matter. When a protection diode is composed of a plurality of TFTs, the constitutions (1) and (3) in which the gate electrode of each TFT is common, the diodes (2), (4), and (1) are used in each TFT Any combination of the configurations of (4) may be used.

As described above, a plurality of TFs are included in a pixel.
In the case of having a TFT, by making the channel direction of the TFT parallel, it is possible to make the shape of the TFT uniform even if a mask misalignment occurs during the manufacture of the TFT array.
Variations in T characteristics (eg, off-state current and Vth) can be suppressed. Therefore, an increase in noise (for example, fixed pattern noise) due to characteristic variations can be suppressed, and an improvement in the detected image and an improvement in work efficiency can be expected.

(Thirteenth Embodiment) FIG. 54 shows a schematic cross section of a TFT array according to a thirteenth embodiment of the present invention. Hereinafter, the manufacturing process will be briefly described.

An SiOx film 302 was formed on the glass substrate 1 by a sputtering method, a CVD method, or the like.

Next, MoTa, Ta, TaN, T
a / TaN, Al alloy, Cu, MoW, etc. 3000A
(Angstrom) and etched to form a gate electrode 309 and a capacitor electrode 305 at the same time. On top of this, SiOx was deposited as a gate insulating film 307 by plasma CVD at a thickness of 3000 A (angstrom). SiNx is laminated to a thickness of 500A (angstrom), the a-Si layer 4 is 1000A (angstrom), and the stopper SiNx layer 312 is 2000A thick.
(Angstrom). Next, the stopper SiNx layer 312 in the TFT portion was patterned according to the gate using backside exposure. Next, the n + a-Si layer 316 is
After depositing at 00A (angstrom), the n + a-Si layer and the a-Si layer in the TFT portion are etched to form a-Si
Layered islands formed. A Mo, Al alloy or the like is deposited thereon and etched to form a drain electrode 313 and a source electrode 315.
Was formed, and the n + a-Si layer in the channel portion of the TFT was etched. On top of this, a passivation SiNx film 31
0 was formed. An organic insulating film 314 was formed thereon using a photosensitive benzocyclobutene-based resin. The thickness of this organic insulating film was about 3 to 4 μm at the thickest part. The organic insulating film has a via hole for contacting the pixel electrode with the source electrode. The shape of this via hole is circular. This is because, when the via hole is formed in a square shape, stress may be concentrated at the via hole corner and cracks or peeling may occur in the pixel electrode. Further, even when the shape of the via hole is a shape in which a square corner is notched, stress concentration at a corner can be reduced.

Next, an AlZr alloy having a thickness of 2000
The pixel electrode 311 was formed by depositing on A (angstrom) and etching. The higher the Zr concentration, the higher the effect of preventing the generation of hillocks in the AlZr alloy, but has a drawback that the etching rate is reduced when an Al etchant is used. The AlZr alloy used for the pixel electrode 311 is Z
r is 15 at. % Was used. For etching of the AlZr alloy, a mixed acid of phosphoric acid, nitric acid and acetic acid having the same composition as the etching solution for Al was used. AlZr at this time
The etching rate of the alloy is １ ／ of the etching rate of Al
It was about. As a result of the etching, the side etching amount of each pixel electrode in the pixel area of 8 cm × 8 cm was 1 thickness.
When using a 500A (angstrom) ITO for the pixel electrode and etching with an over-etching time of 10%, a minimum of 0.5 μm and a maximum of 10 μm are compared with a 2000A (angstrom) thick Al.
Using Zr for pixel electrode, over-etching time is 10%
When the etching was performed as described above, it was possible to greatly reduce the minimum to 0.1 μm and the maximum to 0.2 μm.

In the case of such a side etching amount using AlZr, the resist pattern size for the pixel electrode is 10
At 0 μm × 100 μm, the maximum pixel area is 9980 μm
m ² and the minimum pixel area is about 9960 μm ² . Therefore, the minimum pixel area / maximum pixel area × 100 = 64.6% when ITO is used for the pixel area, whereas the minimum pixel area / maximum pixel area × 100 = 99.8% when AlZr is used. Thus, the variation in the pixel area was significantly reduced.

Also, when the pixel electrode is made of AlZr having a thickness of 2000 A (angstrom) and the etching is performed with an over-etching time of 200%, the maximum and minimum side etching amount is 1 μm or less.

[0311] The pixel electrode has a Ti concentration of 10 at. %
AlTi alloy and a Ti concentration of 15 at. % AT
When the li alloy is used, the minimum pixel area is 99% or more of the maximum pixel area as in the case of AlZr.
The variation in the pixel area was significantly reduced as compared with the case of TO.

(Fourteenth Embodiment) FIG. 56 shows a schematic cross section of a TFT array according to a fourteenth embodiment of the present invention.

In this TFT array, the pixel electrode 3
11 and a source electrode 315, a metal layer 317, a-Si layer 319, SiNx
The layer 320 and the n + a-Si layer 321 were stacked. This makes it possible to reduce the level difference of the organic insulating film in the via hole portion, so that it is possible to prevent a defect such as a crack or disconnection of the pixel electrode in this portion.

(Fifteenth Embodiment) FIG. 57 shows a fifteenth embodiment. This is one in which bumps are formed on the source electrode and the contact portion of the pixel electrode. Here, the bump has a high aspect ratio of height and width. FIG. 58 shows a planar shape of the bump. The planar shape of the bump is basically a narrow stripe. Here, it is a cross. The purpose of such a shape is to firstly reduce the amount of the organic insulating film remaining on the electrode when spin-coating the organic insulating film by forming the stripe on a narrow stripe. The reason why the cross is formed is to increase the strength of the bump and prevent the bump from being peeled or broken during the process. In order to form such a bump, it is preferable to use RIE which is anisotropic etching. By providing such a bump, the upper part of the bump can be exposed on the organic insulating film by uniformly dissolving the organic insulating film in the developing solution, and thereby, without performing a photolithography process. A contact between the source electrode and the pixel electrode can be formed. By adopting this method, it is possible to prevent the problem that the photomask and the organic insulating film are attached and peeled off at the time of exposure in the photolithography process, and to prevent defects such as cracks and peeling occurring in the pixel electrode in the via hole after the pixel electrode is formed. Can be.

As the organic insulating film used in the present invention, an acrylic resin or a polyimide resin other than the benzocyclobutene resin can be used. In addition to the AlZr alloy, a metal that does not generate hillocks due to heating during the Se deposition process, such as Ag, Au,
Cu, Ni, Co, Fe, Ti, Pt, Zr, Cr,
A metal containing one or more metals selected from V, Nb, Mo, Ta, and W as main components is effective. These are metals having a melting point higher than that of Al and a thermal expansion coefficient of Al.
Hillocks are unlikely to occur because of the lower

For Ti, Zr, and Ta, not only the feature that hillock does not occur, but also the effect of improving the sensitivity of the detector can be obtained. These can form an oxide film on the surface, and the oxide film acts as a barrier to one of electrons and holes, and has an effect of reducing leakage current which lowers sensitivity. Conceivable.

As a material for the pixel electrode other than the above metals, for example, Al, Nd, Au, Sm, C
u, Mn, Si, Ni, Co, Y, Fe, Sc, Pd,
Ti, Pt, Zr, Cr, V, Rh, Hf, Ru, B,
An alloy formed by adding one or more metals selected from Ir, Nb, Mo, Ta, Os, Re, and W is effective. These are metals having a higher melting point than Al, and it is considered that hillocks are not generated due to an effect of preventing migration of Al during heat treatment.

An oxide film of about 10 angstroms is formed in the air on the surface of the Al alloy using these additional metals. This oxide film layer has the effect of improving the sensitivity of the detector. This is presumably because the oxide film is chemically stable, so that a Se layer having good quality and excellent electric characteristics can be formed on the oxide film. It is also considered that this oxide film acts as a barrier to one of electrons and holes, and has an effect of reducing leakage current which lowers sensitivity.

Experiments were conducted on the above metals and alloys, and good results were obtained for all of them. In the present embodiment, Se has been described as an example. However, the present invention is not limited to Se. Good results were obtained with other materials such as PbI ₂ .

Further, in addition to the channel stopper type a-Si TFT array according to the present embodiment, the present invention provides a channel etch type a-Si TFT array and a top gate type a-Si TFT array.
Application to an iTFT array or a polysilicon TFT array is also possible.

In a two-dimensional X-ray detector using a TFT array, which is one type of medical X-ray diagnostic apparatus, AlZr is applied to a pixel electrode for collecting charges of each pixel of an amorphous Se layer for converting X-rays into charges. By using alloy, ITO
Since it is possible to prevent a variation in the area of each pixel, which is a problem in the case where is used, it is possible to uniformly form the area of each pixel electrode and obtain an accurate image. In addition, by using an organic insulating film such as a benzocyclobutene-based resin as an insulating film below the pixel electrode, the capacitance between the pixel electrode and the lower electrode wiring, which is a problem when SiNx is used, is reduced, and interlayer short-circuiting occurs. Failure can be prevented.

(Sixteenth Embodiment) The first embodiment of the present invention will be described below.
The details of the imaging device according to the sixth embodiment will be described with reference to the drawings.

FIG. 59 is a view showing a TFT array of an imaging device according to the sixteenth embodiment of the present invention.

In FIG. 59, the TFT array has a signal line S
m, a scanning line Gn, a charge reading switch TFT1, a storage capacitor Cs, and a pixel P (m,
n) is a first area in an m × n array,
A signal line Sm and a scanning line Gn are provided in the periphery of the pixel region, and each includes a detection amplifier (not shown) and a second region connected to a scanning line driving circuit (not shown). In the second area, the signal line Sm and the scanning line Gn are connected to the terminals of the electrostatic discharge means TFTm and TFTn, respectively. One terminal of TFTm and TFTn is connected to an auxiliary wiring SR surrounding the periphery of the first region.
m, TFTn, SR, all signal lines Sm and scanning lines G
n are connected.

When a potential difference occurs due to static electricity between the signal line Sm and the scanning line Gn during the manufacture of the TFT array, charges move through the electrostatic discharge means TFTm and TFTn, and the signal line Sm and the scanning line Gn are equipotential. become. Therefore, the potential difference between the gate electrode and the source and drain electrodes due to static electricity is reduced, and the electrostatic breakdown of the TFT can be prevented.

Accordingly, the electrostatic discharge means T is provided in the second area.
By configuring the FTm, the TFTn, and the auxiliary wiring SR, point defects and line defects due to electrostatic breakdown at the time of manufacturing a TFT array are reduced, and a good image can be obtained.

FIG. 60 shows the basic structure of the electrostatic discharge means TFTm and TFTn. Electrostatic discharge means TFTm, TFT
It is convenient that n is a TFT that can be manufactured in the same step as the charge readout switch formed in the first region without increasing the number of steps. Further, the TFT has a diode configuration in which the gate electrode and the drain electrode are shared. FIG. 61 shows IV characteristics of the electrostatic discharge means shown in FIG. When the voltage becomes higher than a predetermined voltage due to static electricity, the TFT is turned on, thereby preventing application of a high voltage that may destroy the TFT.

FIG. 62 shows the electrostatic discharge means TFTm, TFT
n shows another example. Electrostatic discharge means TFTm, TFTn
It is important that one end is connected to the signal line Sm or the scanning line Gn, and the other end is connected to the auxiliary wiring SR. The number of TFTs, or the structure such as series or parallel, depends on the application and design. Various changes may be made.

(Seventeenth Embodiment) FIG. 63 is a view showing a TFT array of an imaging device according to a seventeenth embodiment of the present invention. The basic configuration, operation, and the like are the same as those in the sixteenth embodiment. Corresponding components have the same reference characters allotted, and detailed description thereof will not be repeated.

In FIG. 63, the TFT array has a signal line S
m, a scanning line Gn, a charge reading switch TFT1, a storage capacitor Cs, and a pixel P (m.
n) is a first area in an m × n array,
A signal line Sm and a scanning line Gn are provided around the first region, and each includes a detection amplifier (not shown) and a second region connected to a scanning line driving circuit (not shown).

In the second area, the signal line Sm and the scanning line G
n is respectively connected to the terminals of the electrostatic discharge means TFTm and TFTn. One terminal of each of TFTm and TFTn is connected to an auxiliary wiring SR surrounding the periphery of the first region.
The signal line Sm and the scanning line Gn are formed by FTm, TFTn, and SR.
Are all connected. At this time, a part of the common wiring SR is drawn out to the end of the TFT array.

When a potential difference due to static electricity occurs between the signal line Sm and the scanning line Gn during the manufacture of the TFT array, the 16th
In the same manner as in the first embodiment, electric charges move through TFTm and TFTn, and the signal line Sm and the scanning line Gn become equipotential. Therefore, the potential difference between the gate electrode and the source and drain electrodes due to static electricity is reduced, and the electrostatic breakdown of the TFT can be prevented. Point defects and line defects due to electrostatic breakdown are reduced, and a good image can be obtained.

The electrostatic discharge means TFTm, T shown in FIG.
The FTn and the common wiring SR are required when manufacturing a TFT array in which static electricity is generated. However, the TFT array is connected to a detection amplifier and a scanning line driving circuit, and is a function that is not required when actually detecting an image. However, it is difficult to eliminate these circuits because they are formed on the TFT array.

If there is a potential difference between the signal line Sm and the common line SR or between the scanning line Gn and the common line SR, when the electrostatic discharge means TFTm, TFTn and the common wiring SR are provided, a current flows through the electrostatic discharge means TFTm and TFTn. It becomes a noise source for the detection amplifier. Therefore, it is necessary to determine the potential of the common wiring SR so that no potential difference occurs between these wirings.

However, the scanning line Gn is set to a potential lower than the source electrode potential of the TFT 1 (ie, the signal line Sm) in order to suppress the off-leak current of the charge reading switch TFT1. Therefore, the signal line Sm and the scanning line Gn do not have the same potential, and the common line SR on the signal line Sm side
m and the common line SRn on the scanning line Gn side need to be set to appropriate potentials.

[0336] After the common wiring SR has been
The separation into m and SRn can be made by cutting the portion drawn to the end of the TFT array shown in FIG.
When the glass substrate is cut into a desired size, the glass substrate is shaved at the end of the TFT array to remove burrs, thereby preventing damage to the TFT array when mounting a signal readout circuit, a scanning line driving circuit, or the like. At this time, the drawer part is also shaved at the same time.
m and SRn can be separated.

FIG. 64 shows T when SRm and SRn are separated from each other.
2 shows a configuration of an FT array. By supplying the same potential to SRm and the same potential as the signal line Sm, and SRn to the same potential as the scanning line Gn, no noise current flows through the TFTm and TFTn. Therefore, a good image with little noise is obtained as the detected image.

The structure of the electrostatic discharge means TFTm and TFTn is the same as that of the sixteenth embodiment, and is shown in FIGS.

FIG. 60 shows the basic structure of the electrostatic discharge means TFTm and TFTn. Electrostatic discharge means TFTm, TFT
It is convenient that n is a TFT that can be manufactured in the same step as the charge readout switch formed in the first region without increasing the number of steps. Further, the TFT has a diode configuration in which the gate electrode and the drain electrode are shared. FIG. 61 shows IV characteristics of the electrostatic discharge means shown in FIG. When the voltage becomes higher than a predetermined voltage due to static electricity, the TFT is turned on, thereby preventing application of a high voltage that may destroy the TFT.

FIG. 62 shows the electrostatic discharge means TFTm, TFT
n shows another example. The electrostatic discharge means Tm and TFTn are
It is important that one end is connected to the signal line Sm or the scanning line Gn, and the other end is connected to the auxiliary wiring SR.
The number of TFTs or the structure such as series or parallel may be variously changed depending on the application and design.

As described above, according to the imaging apparatus of the present embodiment, it is possible to prevent the charge readout switch from being destroyed due to static electricity at the time of manufacturing the TFT array. can get. Further, by separating the signal line side and the auxiliary wiring of the scanning line and applying an optimum potential to each, the thin film transistor of the electrostatic discharge means does not become a noise source, and the detected image becomes a good image with little noise.

[0342]

As described in detail above, according to the first aspect of the present invention, the scanning lines and the bias lines are provided on separate layers, and an insulating layer is interposed between them. So
No short circuit occurs between the scanning line and the bias line, and the yield is improved. In addition, the direct conversion method X
In a line flat detector, as a measure against the high voltage that can be applied to the reading TFT, the use of a protection diode enables the fluoroscopic mode. However, in order to make full use of the function of the protection diode, the protection mode must be used. A voltage must be supplied to the diode. Therefore, by laying out the power supply line, an X-ray flat panel detector that avoids a new noise on a signal, an X-ray flat panel detector that makes it difficult to reduce the yield of manufacturing a TFT array, a reduction in yield, and ,
It is possible to obtain an X-ray flat panel detector in which a reduction in the area for pixel capacitance due to the protection diode and the power supply line is reduced.

By using the above means, in a direct conversion type X-ray flat panel detector which is one of the X-ray imaging apparatuses of a medical X-ray diagnostic apparatus, a bias line for a protection diode used as a measure against a high voltage of a pixel. Can be formed with less occurrence of parasitic capacitance on the signal line, without significantly lowering the yield, and increasing the pixel capacitance.

In the image pickup apparatus according to the present invention, the protection diode is provided between the substrate and the pixel electrode, and is provided so as to be covered by the pixel electrode. The electrode functions as a shield for the protection diode. Therefore, the protection diode is hardly affected by the incident X-ray, and the protection TFT
This prevents fluctuations in the off-state current and dielectric breakdown of the protection diode.

In the direct conversion type X-ray flat panel detector, as a measure against a high voltage that can be applied to the read-out TFT, the use of a protection diode enables a fluoroscopic mode, and a sufficiently weak signal is measured. For this purpose, it is necessary to reduce the off-current of the protection TFT and its fluctuation. In the present invention, since the insulating film is provided, the protection TFT
Leakage current and its fluctuation can be reduced.
In addition, application of an excessive voltage to the protection diode can be prevented.

In the image pickup apparatus according to the present invention, since the first thin film transistor and the second thin film transistor are arranged so that their respective channel directions are parallel to each other, the mask is misaligned. Occurs, Vth and off-state current are offset between the thin film transistors in the same pixel. As a result, an image pickup device including a thin film transistor having no variation in characteristics can be obtained.

When there are a plurality of thin film transistors in a pixel, by making the channel directions of the thin film transistors parallel, it becomes possible to make the shape of the thin film transistors uniform even if a mask misalignment occurs, thereby suppressing variation in characteristics. be able to. Therefore, an increase in the cause due to the characteristic variation can be suppressed, and the detection image and the working efficiency can be improved.

According to the present invention, the pixel electrode is disposed adjacent to the photoelectric conversion film, and the pixel electrode is formed of Ag, Au, Cu, Ni, Co, Fe, Ti,
A metal selected from the group consisting of Pt, Zr, Cr, V, Nb, Mo, Ta, W, or an alloy containing one or more metals selected from the group, or Ag, Nd, A in Al
u, Sm, Cu, Mn, Si, Ni, Co, Y, Fe,
Sc, Pd, Ti, Pt, Zr, Cr, V, Rh, H
f, Ru, B, Ir, Nb, Mo, Ta, Os, Re,
Since it is formed from an alloy to which one or more metals selected from the group consisting of W are added, it is possible to prevent a change in resolution due to side etching and a hillock in a pixel electrode.

In the present invention, a benzocyclobutene resin, an acrylic resin, or a polyimide resin is used for an interlayer insulating film below a pixel electrode, and an Al alloy or a metal having a higher melting point than Al is used for a pixel electrode.

The organic insulating film can be formed by applying a raw material on a substrate by spin coating and then baking, so that it is easy to form a film having a thickness of 3 μm or more. By using an organic insulating film having a low dielectric constant and a thicker film instead of SiNx as an insulating film below the pixel electrode, the capacitance of the pixel electrode and the lower electrode wiring can be reduced, and thus the electrode wiring can be reduced. Signal pulse distortion and delay can be prevented. In addition, by increasing the film thickness, it is possible to prevent an interlayer short-circuit defect occurring between the pixel electrode and the lower electrode wiring, thereby improving the production yield.

[0351] In the imaging device of the present invention, the image forming apparatus is interposed between the signal line and the auxiliary wiring in the second region and between the scanning line and the auxiliary wiring. When a potential difference between the signal line and the scanning line is equal to or more than a predetermined value, an electrostatic discharge unit is provided to short-circuit and make the signal line and the scanning line equipotential. It is possible to prevent a short circuit therebetween from breaking the thin film transistor.

The wiring of the electrostatic breakdown preventing TFT connected to the signal line is kept at the same potential as the signal line, and the wiring of the electrostatic breakdown preventing TFT connected to the scanning line is connected to the scanning line. Since the potentials are the same, current does not flow through the TFT, and the occurrence of thermal noise, which is a noise source, is prevented.

Furthermore, the wiring of the TFT for preventing electrostatic breakdown is made common during the manufacture of the array, and is separated into the signal line side and the scanning line side after the completion of the array. This makes it possible to supply a suitable potential to each of the signal line and the scanning line.

[Brief description of the drawings]

FIG. 1 is a plan view of an X-ray imaging apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the X-ray imaging apparatus according to the first embodiment of the present invention.

FIG. 3 is a plan view of an X-ray imaging apparatus according to a second embodiment of the present invention.

FIG. 4 is a sectional view of an X-ray imaging apparatus according to a second embodiment of the present invention.

FIG. 5 is a plan view of an X-ray imaging apparatus according to a second embodiment of the present invention.

FIG. 6 is a plan view of an X-ray imaging apparatus according to a second embodiment of the present invention.

FIG. 7 is a plan view of an X-ray imaging apparatus according to a second embodiment of the present invention.

FIG. 8 is a plan view of an X-ray imaging apparatus according to a third embodiment of the present invention.

FIG. 9 is a sectional view of an X-ray imaging apparatus according to a third embodiment of the present invention.

FIG. 10 is a plan view of an X-ray imaging apparatus according to a fourth embodiment of the present invention.

FIG. 11 is a sectional view of an X-ray imaging apparatus according to a fourth embodiment of the present invention.

FIG. 12 is a plan view of an X-ray imaging apparatus according to a modification of the fourth embodiment of the present invention.

FIG. 13 is a plan view of an X-ray imaging apparatus according to a modification of the fourth embodiment of the present invention.

FIG. 14 is a plan view of an X-ray imaging apparatus according to a modification of the fourth embodiment of the present invention.

FIG. 15 is a plan view of an X-ray imaging apparatus according to a fifth embodiment of the present invention.

FIG. 16 is a sectional view of an X-ray imaging apparatus according to a fifth embodiment of the present invention.

FIG. 17 is a plan view of an X-ray imaging apparatus according to a sixth embodiment of the present invention.

FIG. 18 is a sectional view of an X-ray imaging apparatus according to a sixth embodiment of the present invention.

FIG. 19 is a plan view of an X-ray imaging apparatus according to a modification of the sixth embodiment of the present invention.

FIG. 20 is a sectional view of an X-ray imaging apparatus according to a modification of the sixth embodiment of the present invention.

FIG. 21 is a plan view of an X-ray imaging apparatus according to a modification of the seventh embodiment of the present invention.

FIG. 22 is a sectional view of an X-ray imaging apparatus according to a modification of the seventh embodiment of the present invention.

FIG. 23 is a circuit diagram of a conventional imaging device.

FIG. 24 is a schematic sectional view of a conventional imaging device.

FIG. 25 is a circuit diagram of a conventional imaging device.

FIG. 26 is a circuit diagram of a conventional imaging device.

FIG. 27 is a circuit diagram of a conventional imaging device.

FIG. 28 is a circuit diagram of an X-ray imaging apparatus according to an eighth embodiment of the present invention.

FIG. 29 is a plan view of an X-ray imaging apparatus according to an eighth embodiment of the present invention.

FIG. 30 is a sectional view of an X-ray imaging apparatus according to an eighth embodiment of the present invention.

FIG. 31 is a view showing characteristics of the pixel circuit according to the eighth embodiment of the present invention.

FIG. 32 is a circuit diagram of an X-ray imaging device using a series protection diode.

FIG. 33 is a circuit diagram of an X-ray imaging device using an amplification type protection diode.

FIG. 34 shows T of the imaging apparatus according to the ninth embodiment of the present invention.
FIG. 3 is a diagram illustrating one pixel of the FT array.

FIG. 35 shows T of the imaging apparatus according to the ninth embodiment of the present invention.
It is a circuit diagram of an FT array.

FIG. 36 is a diagram showing a shape of a TFT when a mask shift occurs.

FIG. 37 is a diagram showing a shape of a TFT when a mask shift occurs.

FIG. 38 is a diagram showing a state in which the pixel of FIG. 34 is applied to the entire TFT array.

FIG. 39 shows T of the imaging apparatus according to the ninth embodiment of the present invention.
FIG. 3 is a diagram illustrating one pixel of the FT array.

FIG. 40 is a diagram showing a configuration example of a protection diode TFT2.

FIG. 41 is a diagram illustrating one pixel of a TFT array of an imaging device according to a tenth embodiment of the present invention.

FIG. 42 is a circuit diagram of a TFT array of the imaging device according to the tenth embodiment of the present invention.

FIG. 43 is a diagram showing a state in which the pixel shown in FIG. 41 is applied to the entire TFT array.

FIG. 44 is a diagram illustrating one pixel of a TFT array of an imaging device according to an eleventh embodiment of the present invention.

FIG. 45 is a circuit diagram of a TFT array of the imaging device according to the eleventh embodiment of the present invention.

FIG. 46 is a diagram showing a state in which the pixel shown in FIG. 44 is applied to the entire TFT array.

FIG. 47 is a diagram illustrating one pixel of a TFT array of an imaging device according to a twelfth embodiment of the present invention.

FIG. 48 is a diagram showing a state in which the pixel shown in FIG. 47 is applied to the entire TFT array.

FIG. 49 is a diagram showing a configuration of an imaging device using an a-SiTFT imaging device.

FIG. 50 is a diagram showing an outline of an a-SiTFT imaging device.

FIG. 51 is a diagram schematically illustrating an imaging device in which a diode is provided in a pixel.

FIG. 52 is a diagram illustrating an outline of an AMI imaging device.

FIG. 53 is a diagram illustrating the method of manufacturing the TFT array.

FIG. 54 is a cross-sectional view showing a structure of a TFT array according to a thirteenth embodiment of the present invention.

FIG. 55 is a cross-sectional view showing a structure of a TFT array section of a conventional imaging device.

FIG. 56 is a sectional view showing a structure of a TFT array section according to a fourteenth embodiment of the present invention.

FIG. 57 is a cross-sectional view showing a structure of a TFT array according to a fifteenth embodiment of the present invention.

FIG. 58 is a plan view showing the shape of a bump electrode.

FIG. 59 is a diagram illustrating a TFT array of an imaging device according to a sixteenth embodiment of the present invention.

FIG. 60 is a diagram showing a basic configuration of electrostatic discharge means TFTm and TFTn.

FIG. 61 is a diagram showing IV characteristics of the electrostatic discharge means.

FIG. 62 is a diagram showing a configuration of electrostatic discharge means TFTm and TFTn.

FIG. 63 is a diagram showing a TFT array of an imaging device according to a seventeenth embodiment of the present invention.

FIG. 64 is a diagram showing a TFT array when SRm and SRn are separated.

[Explanation of symbols]

 7 ... signal readout line (signal line) 9 ... gate line (scanning line) 15 ... pixel capacitance 17 ... gate of TFT 21 ... gate of TFT for protection diode 25 ... voltage supply Line 33: Source of TFT 35: Drain of TFT 37: Source of TFT for protection diode 39: Drain of TFT for protection diode 61: Lower pixel electrode 65: Overlay type Pixel electrode 101: photoelectric conversion film 103: capacitance between photoelectric conversion film and pixel electrode 105: TFT 109: power supply e: pixel

Continued on the front page (72) Inventor Akira Kanno 33 Shinisogocho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside Toshiba Production Technology Research Institute (72) Inventor Kohei Suzuki 33 Shinisogocho, Isogo-ku, Yokohama-shi, Kanagawa Toshiba Corporation Within the Institute of Industrial Science (72) Inventor Norihiko Ueura Inside the Toshiba Institute of Industrial Science 33, Shinisogo-cho, Isogo-ku, Yokohama-shi, Kanagawa

Claims (5)

[Claims] 1. A photoelectric conversion film, a signal line disposed in a matrix and connected to the photoelectric conversion film, a switching element for opening and closing between the photoelectric conversion film and the signal line, A scanning line for transmitting a drive signal; a protection non-linear element connected to each of the photoelectric conversion films and for flowing an excessive charge to a bias line when the amount of charge stored in the photoelectric conversion film is equal to or more than a predetermined amount; An imaging device comprising: an insulating layer interposed between a line and the bias line. 2. A substrate, a plurality of pixel electrodes disposed in a matrix on the substrate, and disposed between the substrate and each of the pixel electrodes so as to be covered by the pixel electrodes. And a protection nonlinear element or bias line. 3. A plurality of pixel electrodes arranged in a matrix, a first thin film transistor connected to each of the pixel electrodes, and a channel between the first thin film transistors connected to each of the pixel electrodes. An imaging device, comprising: a second thin film transistor arranged so that directions are parallel. 4. A photoelectric conversion film, which is disposed adjacent to the photoelectric conversion film, and wherein Ag, Au, Cu, Ni, Co, Fe, Ti, Pt, Z
a metal selected from the group consisting of r, Cr, V, Nb, Mo, Ta, W, or an alloy containing one or more metals selected from the group, or Ag, Nd, Au, S in Al
m, Cu, Mn, Si, Ni, Co, Y, Fe, Sc,
Pd, Ti, Pt, Zr, Cr, V, Rh, Hf, R
a pixel electrode formed of an alloy obtained by adding one or more metals selected from the group consisting of u, B, Ir, Nb, Mo, Ta, Os, Re, and W. Image sensor. 5. A plurality of pixel electrodes formed in a matrix, a signal line connected to each of the pixel electrodes, a switching element for opening and closing each of the pixel electrodes and the signal line, and a driving signal for the switching element. A first region formed of: a first line formed by: a first line, a first line, a second line, and a second line, wherein both ends of the signal line and both ends of the scanning line are arranged outside the first region. A region, an auxiliary wiring provided in the second region, and between the signal line and the auxiliary wiring in the second region, and between the scanning line and the auxiliary wiring. And an electrostatic discharge unit that short-circuits when the potential difference between the signal line and the scanning line is equal to or greater than a predetermined value to make the signal line and the scanning line equipotential.