JPH09252102A - Image pickup device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a crispy image with less noises, by adjusting and disposing a scanning line and a signal line so that capacitance formed in a crossed section is made smaller than the minimum value of a capacitance range in a photoelectric conversion circuit. SOLUTION: Capacitance formed of a-Si films 16 and protective insulating films 17 for an etching stopper is connected in series besides capacitance formed of a gate insulating film 15 in capacitance formed at the crossed section of a scanning line 13 and a signal line 18. Consequently, the series connection of each insulating-film capacitance is acquired, and crossed-section capacitance can be reduced by approximately half. Accordingly, a noise component from a scanning-line driver-circuit power supply proportional to crossed-section capacitance is reduced approximately half, and a dynamic range can be improved. An image pick-up device having such structure is extremely effective especially when a high dynamic range seen in an X-ray diagnostic device is required. An X-ray dose to a patient can be lowered, and a picked-up image extremely more distinct than conventional devices is obtained even in the same dose.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus for converting an optical signal into an electric signal, and more particularly to an image pickup apparatus for a medical X-ray diagnostic apparatus. It also relates to a medical system using this imaging device.

[0002]

2. Description of the Related Art Imaging devices using photoelectric conversion elements are widely used in video cameras, digital cameras and the like.
It is also used in medical X-ray diagnostic devices in place of conventional silver salt films. 2. Description of the Related Art In recent years, in the medical field, there has been a trend toward making a database of medical data of patients for the purpose of prompt and accurate treatment. This is because a patient generally uses a plurality of medical institutions, and in such a case, proper medical treatment may not be possible without data from other medical institutions. As an example, there is concern about side effects with drugs administered at other medical institutions. Appropriate treatment must be performed in consideration of the drug administered at other medical institutions.

There is also a demand for a database for image data of X-ray photography, and digitization of X-ray photography images is desired. Conventionally, X-ray diagnostic apparatus for medical use has taken an image using a silver salt film, but in order to digitize this, it is necessary to develop the taken film and then scan it again with a scanner or the like, which takes time and effort. Was there. Recently, a method of directly digitizing an image using a CCD camera of about 1 inch has been realized. However, for example, when photographing a human lung, since an area of about 20 cm × 30 cm is photographed, an optical device for condensing light is required, and the enlargement of the device poses a problem.

As a method for solving these two problems, an image pickup device using a thin film transistor such as an a-Si TFT (amorphous silicon thin film transistor) has been proposed.

FIG. 7 is a diagram schematically showing the structure of a conventional image pickup device using such an a-Si TFT. In the image pickup device shown in FIG. 7, the pixels e1,1 which are the pixels at the address (1,1) are a-SiTFT 144 and the photoelectric conversion film 14.
0 and the pixel capacitance 142. The pixels e having such a configuration are formed in an array of 2000 (horizontal) × 2000 (vertical array).
e2000 and 2000 indicate pixels at the address (2000, 2000). The photoelectric conversion film 140 has a power source 148.
To apply a bias voltage. a-Si TFT1
Reference numeral 44 is connected to the signal line 118 and the scanning line 113, and the scanning line driving circuit 152 controls ON / OFF.
The end of the signal line 118 is connected to the signal detecting amplifier 154 through the changeover switch 146. When light is incident on a pixel, a current flows through the photoelectric conversion film (photodiode) 140, and charges are accumulated in the photoelectric conversion circuit configured by this photoelectric conversion film and the pixel capacitor 142. The scanning line driving circuit 152 drives the scanning lines 113 to drive one scanning line 113.
When all the TFTs connected to are turned on, the charge accumulated in the photoelectric conversion circuit passes through the signal line 118 and the amplifier 1
It is transferred to the 54 side. The charge is input to the amplifier 154 for each pixel by the changeover switch 146 and converted into a dot-sequential signal which can be displayed on a display device such as a CRT or a liquid crystal display device. The amount of charge varies depending on the amount of light that enters the pixel,
The output amplitude of the amplifier 154 changes.

In the system of the image pickup apparatus shown in FIG. 7, the amplifier 1 is used.
The output signal of 54 can be directly converted into a digital image by A / D conversion.

However, there is a problem to be solved in order to use such an image pickup device using a TFT for medical purposes. One of them is the improvement of image quality, and the reduction of noise is a particular problem. Unless a clear image without noise can be obtained, it cannot be used as a medical imaging device.

The charge accumulated in the pixel is transferred to the amplifier 154, which generally has a high resistance input. Therefore, the output is also affected by a weak disturbance, which causes deterioration in image quality. Scan line 1 as a factor of disturbance
The noise from 13 is given. Scan line 113 is signal line 1
18 intersects with the insulating layer through the insulating layer to form a capacitance, but when the power supply potential of the scanning line driving circuit 152 changes, electric charge appears in the capacitance at the intersection of the scanning line 113 and the signal line 118,
This charge will also be transferred to the amplifier 154.

FIG. 8 is a diagram schematically showing an intersection of the scanning line 113 and the signal line 118.

FIG. 9 is a view showing a cross section in the MN direction at the intersection of the scanning line 113 and the signal line 118 shown in FIG.

On the glass substrate 111, for example, MoTa or M
A scanning line 113 made of a metal such as OW is formed, and a gate insulating film 115 made of SiOx or SiNx is formed on the scanning line 113.
Are formed. The signal line 118 is the gate insulating film 115.
The scan line 113 is insulated and formed through the same film.

Here, for example, both the scanning line width and the signal line width are 10
[Μm] (crossing area S = 100 [μm ² ], gate insulating film thickness d is 0.3 [μm], and insulating film dielectric constant ε is 5, the capacitance C at the crossing is C = εS / Calculated as d = (5 × 8.854 × 10 ^-12 ) × (10 × 10 ^-16 ) ² / (0.3 × 10 ^-6 ) = 14.8 [fF] ………… (Equation 1) When the number of scanning lines is 1000, the signal line 1
18 has an intersection capacitance of 14.8 [pF]. Therefore, the power supply potential of the scanning line drive circuit is 1
Even if it fluctuates by [mV], the charge of 14.8 [fC] remains in the amplifier 1
It will occur on the 54 side. The charges accumulated in the pixels are of the same order (several tens [fC] to several [pC]), so that the charges from the intersections of the scanning lines 113 and the signal lines 118 become a major cause of image quality deterioration. There is.

Particularly, a medical imaging device is required to have a high dynamic range, but there is a problem that the dynamic range must be sacrificed due to the influence of such noise.

Further, particularly in the conventional X-ray imaging apparatus, there is a problem that the X-ray dose to be irradiated must be increased in order to obtain a clear image, which causes a serious problem that the exposure dose to the patient increases. cause.

[0015]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. That is,
It is an object of the present invention to provide an image pickup device which has little noise and has a clear image quality.

Another object of the present invention is to provide an image pickup device having a large dynamic range.

Further, according to the present invention, even when imaging X-rays,
It is an object of the present invention to provide an imaging device that can obtain a clear image quality without increasing the X-ray irradiation amount.

Furthermore, the present invention complicates the manufacturing process,
It is an object of the present invention to provide an image pickup apparatus which can obtain a clear image with low noise and a wide dynamic range without increasing the cost.

[0019]

An image pickup device of the present invention is a signal for reading out a photoelectric conversion circuit, a thin film transistor connected to the photoelectric conversion circuit, and a voltage accumulated in the photoelectric conversion circuit via the thin film transistor. An image pickup device in which lines and scanning lines for driving the thin film transistors, which are formed by intersecting the signal lines, are formed in an array on an insulating substrate, and the scanning lines and the signal lines are the intersections. It is characterized in that it is arranged so that the capacitance formed in the portion is smaller than the minimum value of the capacitance range accumulated in the photoelectric conversion circuit.

In the image pickup device of the present invention, a photoelectric conversion circuit, a thin film transistor connected to the photoelectric conversion circuit, a signal line for reading out a voltage accumulated in the photoelectric conversion circuit via the thin film transistor, An image pickup device in which scanning lines for driving the thin film transistors, which are formed to intersect with signal lines, are formed in an array on an insulating substrate, and the scanning lines and the signal lines are formed at the intersections. It is characterized in that it is arranged so as to have a capacity of less than 10 ^-14 C.

The image pickup device of the present invention is an image pickup device in which a photoelectric conversion circuit and thin film transistors connected to the photoelectric conversion circuit are formed in an array on an insulating substrate, and the photoelectric conversion circuit is formed on the insulating substrate. Read the voltage applied to the photoelectric conversion circuit through the thin film transistor, which is arranged so that the capacitance formed at the intersection becomes smaller than the minimum value of the capacitance range accumulated in the photoelectric conversion circuit. It is characterized in that it has a signal line for outputting and a scanning line for driving the thin film transistor.

The image pickup device of the present invention is an image pickup device in which a photoelectric conversion circuit and thin film transistors connected to the photoelectric conversion circuit are formed in an array on an insulating substrate, and the photoelectric conversion circuit is formed on the insulating substrate. , The capacity formed at the intersection is 10
^A signal line for reading out a voltage applied to the photoelectric conversion circuit through the thin film transistor and a scanning line for driving the thin film transistor, which are arranged so as to be smaller than ^-14 C (coulomb). Is characterized by.

The image pickup device of the present invention is an image pickup device in which a photoelectric conversion circuit and a thin film transistor having a laminated film of an insulating film and a semiconductor film connected to the photoelectric conversion circuit are formed in an array on an insulating substrate. A device, a scanning line for driving the thin film transistor formed on an insulating substrate, and a signal line for reading a voltage accumulated in a photoelectric conversion circuit through the thin film transistor formed on the insulating substrate,
It is characterized in that it is provided with an insulating film formed of the same laminated film as the laminated film of the thin film transistor, which is formed between the scanning line and the signal line in a region where the scanning line and the signal line intersect.

The image pickup device of the present invention is an image pickup device in which a photoelectric conversion circuit and a thin film transistor having a laminated film of an insulating film and a semiconductor film connected to the photoelectric conversion circuit are formed in an array on an insulating substrate. A signal line for reading a voltage accumulated in a photoelectric conversion circuit through the thin film transistor formed on an insulating substrate, a first wiring width formed on an insulating substrate, and And a scanning line for driving the thin film transistor, the scanning line having a second wiring width smaller than a first wiring width formed at an intersection with the signal line.

The method of manufacturing an image pickup device according to the present invention comprises a step of forming a first conductor film in the first region, the second region and the third region of the insulating substrate, and an upper side of the first conductor film. From the above, a step of forming a first insulating film on the insulating substrate, and a step of forming a semiconductor film in the first region and the second region,
Forming a photodiode in the third region;
And a step of forming a second conductor film in the region.

Further, in the image pickup device of the present invention, a plurality of pixel electrodes in which photoelectric conversion films are laminated are arrayed, a signal line arranged between the pixel electrodes, a scanning line arranged between the pixel electrodes, and A thin film transistor (TFT) disposed between the pixel electrode and the signal line and turned on / off by the scanning line;
In an imaging device including a signal reading circuit that reads the pixel electrode potential and a scanning line driving circuit that drives the scanning line, a portion where the signal line and the scanning line intersect is:
The insulating layer is thicker than other portions.

The insulating layer at the intersection of the signal line and the scanning line is a gate insulating film of a thin film transistor made of a SiOx film or a SiNx film, a semiconductor film of a thin film transistor made of an a-Si film, or a thin film transistor of a SiNx film. It may be formed of a laminated film of an insulating film for an etching stopper.

The insulating layer at the intersection of the signal line and the scanning line is formed of a semiconductor film of a thin film transistor made of an a-Si film or a laminated film of insulating films for etching stopper of a thin film transistor made of SiNx film. You may do it.

Further, in the image pickup device of the present invention, a plurality of pixel electrodes in which photoelectric conversion films are laminated are arranged, a signal line arranged between the pixel electrodes, a scanning line arranged between the pixel electrodes, and A thin film transistor (TFT) disposed between the pixel electrode and the signal line and turned on / off by the scanning line;
The wiring width of the scanning line is Wg in a region other than the intersection between the signal reading circuit for reading the pixel electrode potential and the signal line, and the wiring width of the scanning line is n × at the intersection with the signal line. It is characterized in that Wg (where 0 <n ≦ 1).

The photoelectric conversion element may be used according to the wavelength of light received, or may be used in combination with a phosphor.

That is, the present invention is an imaging device in which the electric charges (capacitance) formed at the intersection are reduced in order to reduce noise caused by the intersection of the scanning line and the signal line and obtain a clear image. .

Therefore, in the present invention, the capacitance formed at the intersection of the scanning line and the signal line is adjusted to be smaller than the capacitance stored in the photoelectric conversion circuit formed by the photoelectric conversion element and the storage capacitor. Scanning lines and signal lines are arranged.

Conventionally, the capacitance formed at the intersection of the scanning line and the signal line is of the same order as the capacitance accumulated in the photoelectric conversion circuit, and therefore noise is generated due to the intersection capacitance. In the image pickup apparatus, the capacity of the intersection is halved due to the above configuration.

In order to reduce the capacitance at the intersection, in the image pickup device of the present invention, the film thickness and the dielectric constant of the insulating film for insulating between the signal line and the scanning line are adjusted and arranged. Further, the area of the intersection of the signal line and the scanning line is adjusted and arranged. Further, these may be combined to reduce the capacitance at the intersection.

Further, in the image pickup device of the present invention, the insulating film and the semiconductor film forming the thin film transistor are used as the insulating film for insulating between the signal line and the scanning line.

For example, in the case of an a-Si thin film transistor having an inverted stagger structure, a gate electrode, a gate insulating film, an a-Si semiconductor film and an etching stopper (insulating protective film) are formed on an insulating substrate, and a source / gate is formed on the gate electrode. A drain electrode is formed. Therefore, if the gate insulating film, the a-Si semiconductor film, and the etching stopper are formed at the intersections of the scanning lines and the signal lines, the thickness of the insulating film that insulates the scanning lines from the signal lines becomes large, and the dielectric constant is increased. Even if it is taken into consideration, the capacitance at the intersection is greatly reduced.

All the insulating films forming the thin film transistor may be formed at the intersections, but a part of these films may be formed. For example, the insulating film at the intersection may be formed by the gate insulating film and the semiconductor film, or the insulating film at the intersection may be formed by the gate insulating film, the semiconductor film and the etching stopper. Further, a semiconductor film forming a photodiode may be used.

On the other hand, the wiring width of the scanning line or the signal line may be narrowed at the intersection of the scanning line and the signal line.
Even in this case, the capacity at the intersection is small. Therefore, the influence of noise on imaging is greatly reduced.

Further, the film thickness and the dielectric constant of the insulating film at the intersection may be adjusted and the wiring width of the scanning line or the signal line may be reduced.

As described above, in the image pickup apparatus of the present invention, the film thickness and the permittivity of the insulating film for insulating between the signal line and the scanning line are adjusted and arranged, and the signal line and the scanning line are arranged. Since the area of the intersecting portion is adjusted and arranged, the capacitance of the intersecting portion can be reduced and the influence of noise from the scanning line driving circuit power source can be reduced.

Therefore, when used as an image pickup device requiring a high dynamic range for medical purposes, a clear image without noise can be obtained.

In the method of manufacturing an image pickup device of the present invention, a film forming a thin film transistor or a photoelectric conversion circuit is used at the intersection of a scanning line and a signal line. Therefore,
The imaging device as described above is formed without increasing the number of steps.

The outline of the method of manufacturing the image pickup device of the present invention is as follows. First, the scanning line is formed in the first region, the signal line is formed in the second region which is the thin film transistor forming region, and the third region is the photoelectric conversion circuit forming region. An auxiliary electrode is formed in the area. These can be formed simultaneously.

Then, the first area, the second area and the third area
A gate insulating film is formed on the formed conductor film in the region. Then, an a-Si semiconductor film is formed in the first region and the second region, and a photodiode mainly including the a-Si semiconductor film is laminated and formed in the third region. In addition, the first,
An etching stopper is formed in the second region. If the signal lines are formed so as to intersect from above in the first region,
The intersection structure of the imaging device of the present invention as described above is formed.

[0045]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a diagram schematically showing an example of the configuration of an image pickup apparatus of the present invention. FIG. 2 is an enlarged view showing an intersection of a scanning line and a signal line of the image pickup apparatus of the present invention illustrated in FIG. FIG. 3 is a cross-sectional view schematically showing the structure of the image pickup apparatus of the present invention, and is a view showing a cross section in the AB direction of FIG.

On a silicon wafer or glass substrate 11,
After depositing a refractory metal such as Ta or MoW,
Gate electrode 12, scanning line 13, auxiliary electrode 14
To form Next, a gate insulating film 15 made of silicon nitride (SiOx) or silicon oxide (SiNx) is deposited from above the gate electrode 12, the scanning line 13, and the auxiliary electrode 14. The gate insulating film 15 may be formed of only a silicon nitride film or a silicon oxide film, or a laminated film of these may be used.

Further, an a-Si semiconductor film 16 and an etching stopper protective insulating film 17 made of SiNx are deposited and patterned. In the image pickup device of the present invention, the a-Si semiconductor film 16 and the etching stopper protective insulating film 17 are provided.
Are formed not only in the thin film transistor formation portion but also in the intersection portion of the scanning line 13 and the signal line 18. That is, scan line 1
At the intersection of 3 and the signal line 18, a laminated structure of the scanning line 13, the a-Si film 16, and the etching stopper layer 17 is formed.

Next, the source electrode 19 and the drain electrode 2 of the thin film transistor are made of metal such as aluminum.
0, and the signal line 18 is formed. Further, the pixel electrode 21 is formed of metal such as Ti or IO, and i (or n) -a-SiC: H / ia-Si: H is formed on the pixel electrode 21.
A photodiode 22, which is a photoelectric conversion element made of / p-a-SiC: H, is stacked.

Here, the scanning line 1 having the structure shown in FIG.
The capacitance Cs-g formed at the intersection of 3 and the signal line 18 will be described. 4 and 5 are diagrams schematically showing the capacitance Cs-g formed at the intersection of the scanning line 13 and the signal line 18.

In the structure shown in FIG. 3, the capacitance Cs-g formed at the intersection of the scanning line 13 and the signal line 18 is a-Si in addition to the capacitance C1 due to the gate insulating film 15 as shown in FIG.
The capacitors C2 and C3 formed by the film 16 and the etching stopper protective insulating film 17 are connected in series.

Here, when only the gate insulating film 15 is laminated at the intersection of the scanning line 13 and the signal line 18 (FIG. 5),
The capacitance formed at the intersection when the a-Si film 16 and the etching stopper protective insulating film 17 are deposited (FIG. 4) is calculated using equation (1).

As for the gate insulating film 15, the film thickness d1 is 300 [nm] and the dielectric constant ε1 = 5, as in the formula (1). Further, the film thickness d2 of the a-Si semiconductor film 16 is 50 [n
m] and permittivity ε2 = 11. Furthermore, the film thickness d3 of the etching stopper protective insulating film 17 is 300 [nm],
The dielectric constant ε = 6, and the cross-sectional area S of the insulating films is 100 [μm ² ] in any case. As shown in FIG. 5, the intersection capacitance Cs-g formed only by the gate insulating film 15 is 14.8 [fF] as shown in the equation (1). On the other hand, the gate insulating film 15 is formed at the intersection of the scanning line 13 and the signal line 18.
When a laminated structure of the a-Si semiconductor film 16 and the etching stopper protective insulating film 17 is formed, each insulating film capacitance is connected in series, and the crossing capacitance Cs-g is reduced to about 7.7 [fF], which is about half. be able to.

Therefore, the noise component from the scanning line driving circuit power supply, which is proportional to the capacitance at the intersection, is reduced to about half, and the dynamic range can be improved by about 6 [dB]. In particular, when a high dynamic range is required as in the X-ray diagnostic apparatus, the image pickup apparatus of the present invention is very effective. Furthermore, the X-ray irradiation dose to the patient can be reduced, and
Even with the same irradiation amount, an extremely clear image can be obtained as compared with the conventional one.

The structure in which the a-Si film 16 and the etching stopper protective insulating film 17 are deposited at the intersections of the signal lines and the scanning lines should be manufactured using the conventional TFT manufacturing process as described above. You can Therefore, the noise reduction can be realized without complicating the process and increasing the cost, and the image pickup device with clear image quality can be manufactured.

In the image pickup apparatus illustrated in FIG. 1, a thin film transistor (TFT) using a-Si (amorphous silicon) as a semiconductor film is used, but p-Si (non-single crystal crystalline silicon) or the like a- The thin film transistor may be formed using a semiconductor other than Si. Further, although the inverted stagger type TFT is used here, for example, a coplanar type TFT may be used.

Next, a method of adjusting the area of the intersection to reduce the capacitance of the intersection will be described.

(Embodiment 2) FIG. 6 is a view schematically showing another example of the structure of the image pickup device of the present invention, in which the intersection of the scanning line and the signal line is enlarged. The circuit configuration is the same as in FIG. The same parts as those of the image pickup apparatus illustrated in FIG. 1 are designated by the same reference numerals.

A gate electrode 12 made of MoTa or MoW, a scanning line 13, and an auxiliary electrode 14 are formed on a substrate 11, and a gate insulating film 15 is deposited on a pixel. An a-Si film 16, an etching stopper protective insulating film 17, a source electrode 19, and a drain electrode 20 are formed on the gate electrode 12. The drain electrode 20 is connected to the signal line 18, and the signal line 18 passes through the scanning line 13 and is connected to the amplifier. The source electrode 19 is connected to the pixel electrode 21, and the photodiode 22 is stacked on the pixel electrode 21.

In the image pickup apparatus shown in FIG. 3, the scanning line 13 has a structure in which the wiring width of the portion intersecting with the signal line 18 is narrower than the other portions. Here, the wiring width of the signal line 18 is Ws,
The wiring width of the scanning line 13 other than the intersection of the signal lines 18 is Wg,
The wiring width of the scanning line 13 at the intersection of the signal lines 18 is n × Wg
Intersection capacitance Cs-g and resistance R when (0 <n ≦ 1)
Is examined.

When the wiring width of the scanning line 13 is always constant, that is, when the wiring width of the intersection is not narrowed, the intersection capacitance C
₁ sg and resistance R ₁ are C ₁ sg = (ε × Ws × Wg) / D (Equation 2) R ₁ = (ρ × Ws) / (Wg × d) ...... (Equation 3 ). Here, D is the film thickness of the insulating film, ρ is the resistivity of the scanning line, l is the wiring length, and d is the film thickness of the scanning line.

Next, the wiring width at the intersection with the signal line 18 is set to n.
The cross section capacitance C ₂ sg and the resistance R ₂ when adjusted as × Wg (0 <n ≦ 1) are C ₂ sg = n × {(n × ε × Ws × Wg) / D} .... (Equation 4) R ₂ = (1 / n) × {(ρ × Ws) / (Wg × d)} ... (Equation 5)

Here, the time constant τ ₁ according to the equations 2 and 3,
The time constants τ ₂ according to the equations 4 and 5 have the same value. Further, according to the equation 4, it is possible to reduce the capacitance at the intersection by reducing the wiring width. Therefore, similar to the method of forming the laminated structure at the intersection of the scanning line 13 and the signal line 18 illustrated in FIG. 3 to reduce the capacitance at the intersection, noise due to power supply fluctuation of the scanning line driving circuit is reduced and dynamics are reduced. The range can be increased. In particular, when a high dynamic range is required as in the X-ray diagnostic apparatus, the image pickup apparatus of the present invention is very effective. Further, the image pickup apparatus of the present invention is used for medical X
Use in a line diagnostic device can contribute to better diagnosis.

[0064]

As described above, the image pickup apparatus of the present invention can obtain a clear image with less noise. Further, according to the present invention, the dynamic range of the image pickup device can be increased. Particularly, in the medical X-ray diagnostic apparatus, the imaging apparatus of the present invention which can obtain a clear image with a wide dynamic range and low noise is an imaging apparatus that requires high accuracy and reliability such as a medical X-ray diagnostic apparatus. It can be used in a device.

Further, the X-ray irradiation amount to the patient can be reduced, and even with the same irradiation amount, an extremely clear image can be obtained as compared with the conventional case.

Further, the present invention complicates the manufacturing process,
This is an imaging device that can obtain a clear image with low noise and a wide dynamic range without increasing the cost.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing an example of the configuration of an image pickup apparatus of the present invention.

FIG. 2 is an enlarged view showing an intersection of a scanning line and a signal line of the image pickup apparatus of the present invention.

FIG. 3 is a sectional view schematically showing the structure of an image pickup apparatus of the present invention.

FIG. 4 is a diagram schematically showing an intersection capacitance Cs-g between a scanning line and a signal line.

FIG. 5 is a diagram schematically showing an intersection capacitance Cs-g of a scanning line and a signal line.

FIG. 6 is a diagram schematically showing another example of the structure of the image pickup apparatus of the present invention.

FIG. 7 is a diagram schematically showing a configuration of a conventional imaging device.

FIG. 8 is a diagram schematically showing an intersection of a scanning line and a signal line of a conventional image pickup device.

FIG. 9 is a sectional view schematically showing the structure of a conventional imaging device.

[Explanation of symbols]

11 ... Glass substrate, 12 ... Gate electrode, 13 ... Scan line 14 ... Auxiliary electrode, 15 ... Gate insulating film, 16 ... A
-Si semiconductor film 17 ... Protective insulating film for etching stopper, 18 ... Signal line 19 ... Source electrode, 20 ... Drain electrode, 21 ...
Pixel electrode 22 ... Photodiode

Claims (5)

[Claims] 1. A photoelectric conversion circuit, a thin film transistor connected to the photoelectric conversion circuit, a signal line for reading out a voltage accumulated in the photoelectric conversion circuit via the thin film transistor, and a signal line intersecting the signal line. And a scanning line for driving the thin film transistor, which is formed in an array on an insulating substrate, wherein the scanning line and the signal line have a capacitance formed at the intersection, the photoelectric conversion circuit. An image pickup device, which is arranged so as to be smaller than a minimum value of a capacity range accumulated in the image pickup device. 2. A photoelectric conversion circuit, a thin film transistor connected to the photoelectric conversion circuit, a signal line for reading the voltage accumulated in the photoelectric conversion circuit via the thin film transistor, and a signal line intersecting the signal line. And a scanning line for driving the thin film transistor formed in an array on an insulating substrate, wherein the scanning line and the signal line have a capacitance formed at the intersection of 10 ⁻¹⁴ C An image pickup device, which is arranged so as to be smaller than the above. 3. An image pickup device in which a photoelectric conversion circuit and a thin film transistor having a laminated film of an insulating film and a semiconductor film connected to the photoelectric conversion circuit are formed in an array on an insulating substrate, wherein: A scanning line for driving the thin film transistor formed on an insulating substrate; a signal line for reading the voltage accumulated in the photoelectric conversion circuit via the thin film transistor formed on the insulating substrate; and the scanning line And an insulating film formed of the same laminated film as the laminated film of the thin film transistors, formed between the scanning line and the signal line in a region where the signal line intersects. 4. An imaging device in which a photoelectric conversion circuit and a thin film transistor having a laminated film of an insulating film and a semiconductor film connected to the photoelectric conversion circuit are formed in an array on an insulating substrate, A signal line for reading the voltage accumulated in the photoelectric conversion circuit via the thin film transistor formed on an insulating substrate; a first wiring width formed on the insulating substrate; and the signal line, And a scanning line for driving the thin film transistor, the scanning line having a second wiring width smaller than a first wiring width formed at an intersection portion of the image pickup device. 5. A step of forming a first conductor film in a first region, a second region and a third region of an insulating substrate, and from the upper side of the first conductor film, onto the insulating substrate. A step of forming a first insulating film, a step of forming a semiconductor film in the first region and the second region, a step of forming a photodiode in the third region,
And a step of forming a second conductor film in the region of 1.