JP2001284562A - Array substrate for X-ray detector and inspection method thereof - Google Patents

Abstract

(57) [Problem] To provide an array substrate for an X-ray detection device capable of easily detecting a conduction failure between a pixel electrode and an upper electrode. SOLUTION: For each pixel, a plurality of signal lines, storage capacitor lines, and scanning lines respectively provided on an insulating substrate, a drain is electrically connected to the signal line, and a gate is electrically connected to the scanning line. A plurality of 3s arranged in a matrix
A terminal nonlinear element, a storage capacitor electrode electrically connected to the storage capacitor line, and a pixel electrically connected to a source of the three-terminal nonlinear element and formed on a dielectric film on the storage capacitor electrode An array substrate for an X-ray detection device, comprising: an electrode; and an upper electrode electrically connected to the pixel electrode via a contact hole formed in an insulating film on the pixel electrode. The pixel electrode is divided into a plurality of pieces such that a plurality of storage capacitors each including the storage capacitor electrode and the pixel electrode sandwiching a film are present for each pixel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an array substrate for an X-ray detector and a method for inspecting the same, and more particularly, to easily and accurately inspecting an electrical connection state between a pixel electrode and an upper electrode. The present invention relates to an array substrate for an X-ray detection device and an inspection method thereof.

[0002]

2. Description of the Related Art Conventionally, a large-sized image pickup tube has been used as an X-ray detector. In recent years, an X-ray flat panel detection device which is extremely thin compared to an image pickup tube has been developed.

FIG. 6 is a cross-sectional view schematically showing a schematic configuration of a conventional flat X-ray detector. Flat type X shown in FIG.
The line detector is configured by forming an X-ray-electron conversion layer 300 and a common electrode 400 on an array substrate 100, and the common electrode 400 is connected to a power supply 500.

The array substrate 100 is provided with a charge storage electrode 106, a storage capacitor Cs, and a thin film transistor (TFT) 121 for each pixel. X-ray
The electron conversion layer 300 is made of selenium (Se) or cesium iodide, and functions as a photoconductor under a high electric field when a high voltage is applied to the common electrode 400 by the power supply 500.

[0005] In the X-ray flat panel detecting device constructed as described above, when X-rays are irradiated, the X-ray-electron conversion layer 300
The electrons induced therein are collected on a pixel electrode (not shown) of the array substrate 100 by an electric field formed by the common electrode 400 to which a negative high voltage is applied, and are stored in the storage capacitor Cs.

The charge stored in the storage capacitor Cs of each pixel is converted into a thin film transistor (TF) having a switching function.
T) A voltage output is obtained from the integration amplifier by guiding the selected charge to the integration amplifier constituting the readout circuit. This voltage output is converted into a digital signal by an A / D converter. This is array substrate 100
By performing image processing on all pixels of
An image can be detected as a shadow picture when X-rays are emitted.

FIG. 7 is a plan view showing the structure of one pixel portion of an array substrate of such a conventional flat X-ray detector, and FIG.
Is a sectional view taken along the line AA ′.

In the array substrate 100 of the flat X-ray detector shown in FIG. 7, a plurality of signal lines 103 and a plurality of scanning lines 111 are arranged so as to be orthogonal to each other, and a plurality of storage capacitance lines 105 It is arranged substantially parallel to the line 103.

The storage capacitor line 105 is formed of a low-resistance material directly on the insulating substrate 101 or via an underlayer. The scanning line 111 is formed of a low-resistance material on an interlayer insulating film 112 stacked on the storage capacitor line 105. On the other hand, the signal line 103 is
13 and is formed of a low-resistance material.

In the vicinity of the intersection between the signal line 103 and the scanning line 111, a thin film transistor (TFT) 121 and a pixel electrode 151 connected via the TFT 121 are provided.

In the X-ray flat panel detecting device, the display pixels of the substantially square configuration as described above are arranged in a matrix. The pixel electrode 151 is electrically connected to the upper storage capacitor electrode 142 via the contact hole 152 as shown in FIG. The upper storage capacitor electrode 142 is overlapped with the storage capacitor electrode 106 also serving as the storage capacitor line 105 via the interlayer insulating film 112 to form a storage capacitor (Cs).

On the pixel electrode 151, an organic insulating film 20
1 is formed thereon, and an upper electrode 202 is formed thereon so as to cover the TFT 121 and Cs. The upper electrode 202 is electrically connected to the pixel electrode 151 via the contact hole 203.

[0013]

SUMMARY OF THE INVENTION The array substrate 1 of the active matrix type flat panel detecting device constructed as described above.
When a contact hole is formed in the organic insulating film 201 in the manufacturing process of No. 00, the organic insulating film 201 in the contact hole portion is not completely etched, and a residue of a thin organic film on the order of submicrons remains on the pixel electrode 151. There are cases.

Further, the organic insulating film 2 in the contact hole portion
When the upper electrode 202 is formed, the edge of the pixel electrode 151 that contacts the pixel electrode 151 may be lifted, causing a disconnection. Therefore, a non-conductive defect between the pixel electrode 151 and the upper electrode 202 may occur.

Therefore, the manufactured array substrate 100
Before being subjected to the subsequent manufacturing process of the plane detection device,
Inspections and rejects must be removed. In such an inspection of the array substrate 100, after the completion of the array substrate 100, the TFT 121 is once turned ON, a constant charge is accumulated in the storage capacitor (Cs), and the TFT 121
Is turned off, the TFT 121 is turned on again, and the amount of charge stored in Cs is read. That is, if the read charge amount is smaller than the predetermined value, the fact that some kind of defect has occurred in the pixel is used.

However, the upper electrode 202 and the pixel electrode 151
Is much smaller than Cs. Therefore, even when a conduction failure occurs between the upper electrode 202 and the pixel electrode 151 during the inspection of the array substrate,
Since the capacitance fluctuation was very small, it was not possible to detect the quality of the pixel.

It is another object of the present invention to provide an array substrate for an X-ray detection apparatus capable of easily and accurately detecting a conduction failure between a pixel electrode and an upper electrode. And

It is another object of the present invention to provide a method of inspecting an array substrate for an X-ray detector capable of easily and accurately detecting a conduction failure between a pixel electrode and an upper electrode.

[0019]

In order to solve the above-mentioned problems, the present invention provides a plurality of signal lines, storage capacitor lines, and scanning lines each provided on an insulating substrate; A plurality of pixels, each having a gate electrically connected to the scanning line and arranged in a matrix for each pixel,
A terminal nonlinear element, a storage capacitor electrode electrically connected to the storage capacitor line, and a pixel electrically connected to a source of the three-terminal nonlinear element and formed on a dielectric film on the storage capacitor electrode An array substrate for an X-ray detection device, comprising: an electrode; and an upper electrode electrically connected to the pixel electrode via a contact hole formed in an insulating film on the pixel electrode. An X-ray detection apparatus, wherein the pixel electrode is divided into a plurality of pieces so that a plurality of storage capacitors each including a storage capacitor electrode and the pixel electrode sandwiching a film are present for each pixel. An array substrate is provided.

In the above array substrate for an X-ray detection device, the plurality of divided pixel electrodes may be electrically connected via the upper electrode.

Further, at least one of the plurality of divided pixel electrodes may not be electrically connected to the source of the child nonlinear element before the upper electrode is formed.

Further, an electrode electrically connected to the pixel electrode may be provided in an insulating film between the storage capacitor electrode and the pixel electrode.

The present invention also relates to a method for inspecting the continuity between the pixel electrode and the upper electrode in the array substrate for an X-ray detection device, wherein a step of accumulating electric charges in the plurality of storage capacitors is provided. A method of measuring the amount of charge read from the plurality of storage capacitors, and a step of comparing the amount of charge with a prescribed amount of charge. I do.

Further, the present invention relates to a method for inspecting the continuity between the pixel electrode and the upper electrode in the array substrate for an X-ray detector, wherein the method further comprises:
Accumulating charge in the plurality of storage capacitors, measuring a first amount of charge read from the plurality of storage capacitors, storing the charge in the plurality of storage capacitors after forming the upper electrode X, the step of measuring the second charge amount read from the plurality of storage capacitors, and the step of comparing the first charge amount and the second charge amount. An inspection method of an array substrate for a line detection device is provided.

According to the present invention configured as described above,
When the storage capacitor Cs is divided into two or more, if a conduction failure occurs between the upper electrode and the pixel electrode, the conduction failure can be easily detected at the time of inspection of the array substrate.

For this reason, it is a good idea to select an array substrate having such a defect and to provide only an array substrate having no defect to the steps after the formation of the X-ray-electron conversion film.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view illustrating a configuration of an array substrate according to an embodiment of the present invention.
FIG. 2 is a sectional view taken along the line BB 'of FIG.

In the array substrate 100 according to the present embodiment, as shown in FIG. 1, a plurality of signal lines 103 and a plurality of scanning lines 111 are arranged so as to be orthogonal to each other, and a plurality of storage capacitance lines 105 It is arranged substantially parallel to the signal line 103.

The storage capacitance line 105 is formed on the insulating substrate 101 such as a glass substrate directly or through an underlayer by using a low-resistance material such as aluminum, an aluminum alloy, or molybdenum-tungsten (MoW). Have been.

The scanning line 111 is formed on a 350 nm-thick interlayer insulating film 112 (shown in FIG. 2) made of a silicon oxide film stacked on the storage capacitor line 105 by aluminum, aluminum alloy, or molybdenum / tungsten (FIG. 2). (MoW).

On the other hand, the signal line 103 is formed on the insulating film 113 (shown in FIG. 2), and is made of a low-resistance material such as aluminum, chromium, molybdenum, and the like. In the vicinity of the intersection between the signal line 103 and the scanning line 111, a thin film transistor (TFT) 121 and pixel electrodes 151a and 151b connected via the TFT 121 are provided. The pixel electrodes 151a and 151b are, for example, I
It is formed by TO.

As shown in FIG. 5, the TFT 121 has a gate electrode 302, a gate insulating film 303, a semiconductor film 304, and low-resistance semiconductor films 305a and 305 formed on an interlayer insulating film 301.
05b, a source electrode 306, a drain electrode 307, and a protective film 308 are stacked.

The semiconductor film 304 is made of, for example, a-Si: H
(Hydrogenated amorphous silicon) film.
A gate electrode 302 extending from the scanning line 111 is provided below the semiconductor film 304, and a gate insulating film 303 is stacked between the two.

On the semiconductor film 304, a channel protective film 308 made of silicon nitride is laminated.
Further, one end of the semiconductor film 304 has n + type a-Si:
A low-resistance semiconductor film 305 a made of H is formed, and is electrically connected to the pixel electrode 151 via the source electrode 306.

On the other hand, a low-resistance semiconductor film 305b is formed at the other end of the semiconductor film, and is electrically connected to the signal line 103 via a drain electrode 307 extending from the signal line 103.

In the X-ray flat panel detection device, display pixels having a substantially square shape are arranged in a matrix. As for the number of pixels, for example, in a device having a side of 9 inches, 1536 pixels are arranged in each of the vertical direction and the horizontal direction. In this case, the number of each of the signal lines 103 and the scanning lines 111 is 153.
There are six.

As shown in FIG. 1, the pixel electrodes 151a and 151b are electrically connected to the upper storage capacitor electrodes 142a and 142b via the contact holes 152a and 152b. The upper storage capacitor electrodes 142a and 142b
The storage capacitor electrode 106 also serving as the storage capacitor line 105 is overlapped with an interlayer insulating film 112 interposed therebetween to form a storage capacitor (Cs).

As shown in FIG. 2, the pixel electrodes 151a, 1
An organic insulating film 201 made of an acrylic material or the like is deposited to a thickness of about 4 μm on the surface 51b.
An upper electrode 202 is formed so as to cover 121 and Cs. The upper electrode 202 is made of a material such as ITO or chromium and has contact holes 203a, 203
3b, it is electrically connected to the pixel electrodes 151a, 151b.

As described above, the inspection of the array substrate 100 is performed after the completion of the
Is turned ON once, a constant charge is accumulated in Cs,
After turning off the TFT 121 for a certain period of time,
This is performed by turning on T121 and reading the amount of charge accumulated in Cs.

That is, if the read charge amount is smaller than a predetermined value (for example, the charge amount measured before forming the overlying electrode), the fact that some kind of defect has occurred in the pixel is used.

In the case of the array substrate 100 having the conventional structure shown in FIGS. 7 and 8, one pixel has only one Cs. The capacitance formed between the upper electrode 202 and the pixel electrode 151 is much smaller than Cs. Therefore, even if a conduction failure occurs between the upper electrode 202 and the pixel electrode 151 during the inspection of the array substrate, the quality of the pixel could not be detected due to a small amount of capacitance change.

Therefore, in the present invention, as shown in FIGS. 1 and 2, the storage capacitor Cs in one pixel is divided into two, and each pixel electrode 151a, 151b is connected to the upper electrode 202 and the contact holes 203a, 203b. Through TFT1
The structure was such that it was electrically connected in parallel to the 21 source electrodes.

With such a structure, the total charge amount of the two storage capacitors Cs is read out from the normal pixel during the inspection of the array substrate, but the disconnection of the upper electrode 202 at the end of the organic insulating film 201 occurs. Also, the upper electrode 202 and the pixel electrode 151 due to the thin organic film remaining in the contact hole 203 caused by the poor etching of the organic insulating film 201.
When a conduction failure occurs with the Cs formed by the storage capacitor electrode 142a,
The defective pixel becomes clear because of only the minute.

For example, when the value of the storage capacitance of the conventional array substrate having one storage capacitance is 1.4 pF, this value is determined even if there is a conduction failure between the upper electrode and the pixel electrode. There is not much change before and after the formation of the upper electrode, and therefore, the amount of charge read does not change.

However, when the storage capacity is divided into two,
In the measurement before the formation of the upper electrode, if the value of one storage capacitor is 0.4 pF and the value of the other storage capacitor is 0.9 pF, the pixel electrode related to the other storage capacitor is formed after the formation of the upper electrode. If there is a conduction failure between the upper electrode and the lower electrode, the capacitance between the storage electrode and the upper electrode is only 0.4 pF,
Therefore, the amount of charge read from the storage capacitor also has a small value accordingly.

In this way, it is possible to detect that there is a conduction failure between the pixel electrode related to the other storage capacitor and the upper electrode.

In the above embodiment, the contact holes 203a and 203b between the upper electrode 202 and the pixel electrode 151 are formed for the two storage capacitors, respectively.
This contact hole may be put together. FIG.
Is a schematic plan view of an array substrate 100 according to another embodiment of the present invention, and FIG. 4 is a cross-sectional view taken along the line CC 'of FIG.

In the array substrate 100 according to the embodiment shown in FIGS. 3 and 4, one contact hole 203 between the upper electrode 202 and the pixel electrode 151 is provided for two storage capacitors. In such a configuration, the upper electrode 20
It is not possible to detect a conduction failure between the pixel electrode 151 and the upper electrode 202 due to the disconnection of step 2. However, it is possible to detect a conduction failure due to a thin residue of the organic insulating film 201 when the contact hole 203 is formed.

The structure as shown in FIGS. 3 and 4 requires only one large contact hole 203 to be formed, and does not require a very high precision. Therefore, it is difficult to form a fine contact hole. Adopted in the case.

In the above embodiment, the organic insulating film 201 is used between the pixel electrode 151 and the upper electrode 202.
A silicon nitride film can be used instead of the organic insulating film. Further, in the above embodiment, the storage capacitor Cs is divided into two, but may be divided into three or more.

Further, at least one of the plurality of divided pixel electrodes can be brought into a floating state so as not to be electrically connected to the source of the TFT before forming the upper electrode. By doing so, it is possible to increase the difference between the capacitance before and after the formation of the upper electrode or the amount of read charge, and it is possible to increase the detection sensitivity.

As described above in detail, according to the present invention, by dividing the storage capacitor Cs into two or more parts, when a conduction failure occurs between the upper electrode and the pixel electrode, the conduction failure is reduced. It can be detected when inspecting the array substrate. For this reason, an array substrate having such a defect can be selected, and only an array substrate having no defect can be subjected to processes after the formation of the X-ray-electron conversion film, which is effective in reducing the manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a plan view schematically showing a configuration of an array substrate of a planar X-ray detector according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line BB ′ of FIG. 1;

FIG. 3 is a plan view schematically showing a configuration of an array substrate of a flat X-ray detector according to another embodiment of the present invention.

FIG. 4 is a sectional view taken along the line CC ′ of FIG. 3;

FIG. 5 is a cross-sectional view showing a configuration of a thin film transistor formed on an array substrate of a flat X-ray detector according to one embodiment of the present invention.

FIG. 6 is a sectional view schematically showing a general configuration of a flat panel detector.

FIG. 7 is a plan view schematically showing a configuration of an array substrate of a conventional flat panel detector.

FIG. 8 is a sectional view taken along line AA ′ of FIG. 6;

[Explanation of symbols]

Reference Signs List 100 array substrate 101 glass substrate 103 signal line 105 storage capacitor line 106 storage capacitor electrode 111 scanning line 113 first gate insulating film 121 TFT 142, 142a, 142b upper storage capacitor electrode 151, 151a, 151b: pixel electrode 152, 152a, 152b: contact hole between pixel electrode and upper storage capacitor electrode 201: organic insulating film 202: upper electrode 203, 203a, 203b: upper electrode-pixel electrode contact hole 300: X-ray Electron conversion film 400: Common electrode 500: Power supply

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) G01T 7/00 H04N 5/32 5F088 H01L 27/146 H01L 27/14 K 5F110 29/786 Z 21/336 C 31/09 29/78 612D H04N 5/32 624 31/00 A / F term (reference) 2G014 AA02 AA13 AB21 AB55 AB59 2G036 AA25 AA26 AA27 BA33 BB12 CA06 CA08 2G088 EE01 EE27 FF02 GG21 JJ05 JJ32 JJ33 AJ4A4 AB4 CB05 CB14 DD09 FB09 FB13 FB16 GA10 5C024 AX12 CY44 GX18 GY39 HX23 5F088 AA11 AB01 BA18 BB03 EA04 EA06 GA02 KA08 LA08 5F110 AA24 BB02 BB10 CC07 DD02 EE03 EE06 GG02 NN24 NN04 04

Claims (6)

[Claims] 1. A pixel having a plurality of signal lines, a storage capacitor line, and a scanning line disposed on an insulating substrate, a drain electrically connected to the signal line, and a gate electrically connected to the scanning line, respectively. A plurality of three-terminal non-linear elements arranged in a matrix for each, a storage capacitance electrode electrically connected to the storage capacitance line, and a storage capacitance electrode electrically connected to a source of the three-terminal non-linear element X-ray detection comprising: a pixel electrode formed on an upper dielectric film; and an upper electrode electrically connected to the pixel electrode via a contact hole formed in an insulating film on the pixel electrode. An array substrate for a device, wherein the pixel electrode is divided into a plurality such that a plurality of storage capacitors each including the storage capacitor electrode and the pixel electrode sandwich the dielectric film. Specially X-ray detection device for the array substrate to. 2. The array substrate for an X-ray detection device according to claim 1, wherein said plurality of divided pixel electrodes are electrically connected via said upper electrode. 3. The device according to claim 1, wherein at least one of said plurality of divided pixel electrodes is not electrically connected to a source of said child nonlinear element before forming an upper electrode. 4. The array substrate for an X-ray detection device according to item 1. 4. The X-ray detection device according to claim 1, wherein an electrode electrically connected to said pixel electrode is provided in an insulating film between said storage capacitor electrode and said pixel electrode. Array substrate for equipment. 5. A method for inspecting continuity between said pixel electrode and said upper electrode in the array substrate for an X-ray detection device according to claim 1, wherein said plurality of storage capacitors store electric charges. Inspecting an array substrate for an X-ray detection device, comprising: a step of measuring an amount of charge read from the plurality of storage capacitors; and a step of comparing the amount of charge to a predetermined amount of charge. Method. 6. A method for inspecting continuity between said pixel electrode and said upper electrode in said array substrate for an X-ray detection device according to claim 1, wherein said plurality of said plurality of electrodes are formed before said upper electrode is formed. Storing a charge in a storage capacitor, measuring a first charge amount read from the plurality of storage capacitors, storing the charge in the plurality of storage capacitors after forming the upper electrode, An X-ray detection apparatus comprising: a step of measuring a second charge amount read from the plurality of storage capacitors; and a step of comparing the first charge amount and the second charge amount. Inspection method for array substrate