JP5100799B2 - Liquid crystal display - Google Patents

Description

The present invention relates to an image sensor function and a device having a display function, and in particular, an active matrix panel having a display unit composed of a plurality of pixel electrodes arranged in a matrix and a portable unit having a display unit. The present invention relates to a terminal, an electronic device such as a personal computer having a display portion, and a manufacturing method thereof.

In recent years, TFT technology using polycrystalline silicon called polysilicon TFT has been intensively studied. As a result, it is possible to fabricate a drive circuit such as a shift register circuit by using a polysilicon TFT, and an active matrix type liquid crystal in which a pixel portion and a peripheral drive circuit for driving the pixel portion are integrated on the same substrate. Panels have come into practical use. for that reason,
Liquid crystal panels have been reduced in cost, size, and weight, and are used in various information devices such as personal computers, mobile phones, video cameras and digital cameras, and display portions of mobile devices.

Recently, a pocket-sized small portable information processing terminal device that is more portable than a notebook personal computer and is inexpensive has been put into practical use, and an active matrix liquid crystal panel is used for its display unit. Such an information processing terminal device can input data from a display unit by a touch pen method, but in order to input text / graphics information and video information on a paper surface, an image of a scanner or a digital camera is read. It is necessary to connect with peripheral equipment for Therefore, the portability of the information processing terminal device is impaired. It also puts an economic burden on the user to purchase peripheral equipment.

Active matrix display devices are also used in display units of TV conference systems, TV phones, Internet terminals, and the like. These systems and terminals include a camera (CCD camera) that captures images of a conversation person or user, but the display unit and the reading unit (sensor unit) are individually manufactured and modularized. Therefore, the manufacturing cost is high.

The object of the present invention is to solve the above-mentioned problems and to have a pixel matrix, an image sensor, and peripheral circuits for driving them, that is, having both an imaging function and a display function,
An object is to provide a display device using a novel intelligent semiconductor device.

A further object of the present invention is to manufacture a display device using a new intelligent semiconductor device at low cost by making the image sensor consistent with the pixel matrix, peripheral drive circuit and structure / manufacturing process. There is.

In order to solve the above problems, the present invention has a configuration in which a display semiconductor device and a light receiving semiconductor device are provided over the same substrate. In addition, the liquid crystal display unit including the pixel electrode and the display semiconductor device and the sensor unit including the light receiving semiconductor device are not separately disposed, but the display semiconductor device and the light receiving semiconductor device are provided in one pixel. New element configuration, ie FIG. 1 or FIG.
As shown in FIG. 1, a display device having an image reading function can be downsized and compacted by including a semiconductor device (insulated gate field effect semiconductor device) that controls both display and light reception in one pixel. Turn into.

The first configuration of the invention disclosed in this specification is:
A display unit comprising a pixel matrix having at least a pixel electrode in a matrix and a first semiconductor device connected to the pixel electrode;
At least a photoelectric conversion element and a sensor unit made of a second semiconductor device connected to the photoelectric conversion element are provided on the same substrate surface,
An integrated liquid crystal display panel having an image sensor function, wherein light from the back surface of the substrate is received by the sensor unit.

The second configuration of the present invention is as follows.
A display unit comprising a pixel matrix having at least a pixel electrode in a matrix and a first semiconductor device connected to the pixel electrode;
At least a photoelectric conversion element and a sensor unit made of a second semiconductor device connected to the photoelectric conversion element are provided on the same substrate surface,
The display unit and the sensor unit have the same pixel size,
An integrated liquid crystal display panel having an image sensor function, wherein light from the back surface of the substrate is received by the sensor unit.

The third configuration of the present invention is as follows.
A display unit comprising a pixel matrix having at least a pixel electrode in a matrix and a first semiconductor device connected to the pixel electrode;
At least a photoelectric conversion element and a sensor unit made of a second semiconductor device connected to the photoelectric conversion element are provided on the same substrate,
The first semiconductor device and the second semiconductor device are provided in the same matrix,
The pixel electrode connected to the first semiconductor device is an integrated liquid crystal display panel having an image sensor function, wherein the pixel electrode exists above the second semiconductor device.

The fourth configuration of the present invention is as follows.
A display unit comprising a pixel matrix having at least a pixel electrode in a matrix and a first semiconductor device connected to the pixel electrode;
At least a photoelectric conversion element and a sensor unit made of a second semiconductor device connected to the photoelectric conversion element are provided on the same substrate,
The photoelectric conversion element is composed of at least an upper electrode, a photoelectric conversion layer, and a lower electrode,
The upper electrode is made of a metal having reflectivity for at least visible light,
An integrated liquid crystal display panel having an image sensor function, wherein the lower electrode is made of a transparent conductive film.

The fifth configuration of the present invention is as follows.
A pixel electrode having a pixel electrode arranged in a matrix and a first semiconductor device connected to the pixel electrode;
A method for manufacturing an integrated liquid crystal display panel having an image sensor function, in which an image sensor having a light receiving portion including a photoelectric conversion element and a second semiconductor device connected to the photoelectric conversion element is provided on the same substrate Because
A first step of manufacturing the first semiconductor device and the second semiconductor device on the substrate;
A second step of forming a lower electrode made of a translucent conductive film connected to the second semiconductor device;
A third step of forming a photoelectric conversion layer on the lower electrode;
A fourth step of forming an upper electrode in contact with the photoelectric conversion layer; and a method for manufacturing an integrated liquid crystal display panel having an image sensor function.

The sixth configuration of the present invention is as follows.
A pixel electrode having a pixel electrode arranged in a matrix and a first semiconductor device connected to the pixel electrode;
A method for manufacturing an integrated liquid crystal display panel having an image sensor function, in which an image sensor having a light receiving portion including a photoelectric conversion element and a second semiconductor device connected to the photoelectric conversion element is provided on the same substrate Because
A first step of manufacturing the first semiconductor device and the second semiconductor device on the substrate;
A second step of forming a first insulating film covering at least the first semiconductor device and the second semiconductor device;
A third step of forming a translucent conductive film on the first insulating film;
A fourth step of patterning the translucent conductive film to form a lower electrode connected to the second semiconductor device;
A fifth step of forming a photoelectric conversion layer on the lower electrode;
A sixth step of forming an upper electrode in contact with the photoelectric conversion layer; and a method for manufacturing an integrated liquid crystal display panel having an image sensor function.

The seventh configuration of the present invention is as follows.
The photoelectric conversion element is composed of a lower electrode, a photoelectric conversion layer formed on the lower electrode, and an upper electrode formed on the photoelectric conversion layer,
A sensor unit comprising at least one active element connected to the photoelectric conversion element is provided on an insulating substrate;
The upper electrode is made of a metal having reflectivity for at least visible light,
An integrated liquid crystal display panel having an image sensor function, wherein the lower electrode is made of a conductive film having transparency to at least visible light.

The eighth configuration of the present invention is as follows.
A display unit comprising a pixel matrix having at least a pixel electrode in a matrix and an active element connected to the pixel electrode;
At least a photoelectric conversion element and a sensor unit composed of an active element group connected to the photoelectric conversion element are provided on the same substrate surface,
An integrated liquid crystal display panel having an image sensor function, wherein light from the back surface of the substrate is received by the sensor unit.

The ninth configuration of the present invention is as follows.
A display unit comprising a pixel matrix having at least a pixel electrode in a matrix and an active element connected to the pixel electrode;
At least a photoelectric conversion element and a sensor unit composed of an active element group connected to the photoelectric conversion element are provided on the same substrate surface,
The display unit and the sensor unit have the same pixel size,
An integrated liquid crystal display panel having an image sensor function, wherein light from the back surface of the substrate is received by the sensor unit.

The tenth configuration of the present invention is
A display unit comprising a pixel matrix having at least a pixel electrode in a matrix and an active element connected to the pixel electrode;
At least a photoelectric conversion element and a sensor unit composed of an active element group connected to the photoelectric conversion element are provided on the same substrate,
The active element and the active element group are provided in the same matrix,
The pixel electrode connected to the active element is present above the active element group, and is an integrated liquid crystal display panel having an image sensor function.

The eleventh configuration of the present invention is
A display unit comprising a pixel matrix having at least a pixel electrode in a matrix and an active element connected to the pixel electrode;
At least a photoelectric conversion element and a sensor unit composed of an active element group connected to the photoelectric conversion element are provided on the same substrate,
The photoelectric conversion element is composed of at least an upper electrode, a photoelectric conversion layer, and a lower electrode,
The upper electrode is made of a metal having reflectivity for at least visible light,
An integrated liquid crystal display panel having an image sensor function, wherein the lower electrode is made of a transparent conductive film.

In the eighth to eleventh configurations, the active element group includes at least an amplification transistor, a reset transistor, and a selection transistor.

The twelfth configuration of the present invention is
Pixel electrodes arranged in a matrix, and a pixel matrix having active elements connected to the pixel electrodes;
An image sensor having a light receiving portion having a photoelectric conversion element and an active element group connected to the photoelectric conversion element is a method for manufacturing an integrated liquid crystal display panel having an image sensor function provided on the same substrate. And
A first step of producing the active element and the active element group on the substrate;
A second step of forming a lower electrode made of a translucent conductive film connected to the active element group;
A third step of forming a photoelectric conversion layer on the lower electrode;
A fourth step of forming an upper electrode in contact with the photoelectric conversion layer; and a method for manufacturing an integrated liquid crystal display panel having an image sensor function.

The thirteenth configuration of the present invention is
Pixel electrodes arranged in a matrix, and a pixel matrix having active elements connected to the pixel electrodes;
An image sensor having a light receiving portion having a photoelectric conversion element and an active element group connected to the photoelectric conversion element is a method for manufacturing an integrated liquid crystal display panel having an image sensor function provided on the same substrate. And
A first step of producing the active element and the active element group on the substrate;
A second step of forming a first insulating film covering at least the active element and the active element group;
A third step of forming a translucent conductive film on the first insulating film;
Patterning the translucent conductive film to form a lower electrode connected to the active element group;
A fifth step of forming a photoelectric conversion layer on the lower electrode;
And a sixth step of forming an upper electrode in contact with the photoelectric conversion layer. A method for manufacturing an integrated liquid crystal display panel having an image sensor function.

In the twelfth or thirteenth configuration of the present invention, the active element group includes:
At least an amplification transistor, a reset transistor, and a selection transistor are included.

The manufacturing process of the present invention is the same as that of a conventional display device except for the manufacturing process of the photoelectric conversion element. Therefore, since the conventional manufacturing process can be used, it can be manufactured easily and inexpensively. Further, even if the device manufactured according to the present invention is equipped with a sensor function, the shape and size of the conventional panel and the substrate do not change. Therefore, it can be reduced in size and weight.

The light receiving area of the sensor cell is approximately the same as the pixel area of the display cell, and the single crystal CC
Since it is larger than D, the sensor of the present invention can be highly sensitive. Furthermore, the power consumed by this configuration is very small, and the power consumed by the image sensor can be reduced compared to the CCD structure.

Pixel cross-sectional view of the present invention An example of the surface arrangement | positioning figure and back surface arrangement | positioning figure of one pixel. Circuit diagram of the present invention LCD panel overall view The figure which shows the process of forming a sensor part and a display element in one pixel. The figure which shows the process of forming a sensor part and a display element in one pixel. Pixel sectional view of Example 2 Production process diagram in Example 2 Production process diagram in Example 2 Circuit diagram of Example 3 Application examples of the present invention

The following are typical forms using the present invention. In the invention disclosed in this specification, as shown in FIG. 1, a novel element configuration basically having one display semiconductor device (TFT) and at least one light receiving semiconductor device (TFT) in one pixel. And Then, an electric voltage is applied to the liquid crystal aligned by the alignment film formed on the reflective electrode of this element, display is performed on the liquid crystal display surface, and an optical signal incident on the back surface of the liquid crystal display surface is read by the sensor unit. Suppose that the device captures video. 4A and 4B show a panel configuration diagram of the present invention. FIG. 3 is a simplified circuit diagram of the panel of the present invention.

As shown in FIG. 4A, the liquid crystal panel is provided with a sensor driving circuit 403 for driving the sensor portion and a display driving circuit 404 for driving the display portion around the display portion and the sensor portion 402. It is an arrangement.

In the present invention, after the sensor unit reads optical signal data incident on the back surface of the liquid crystal display surface, the data is stored in an external storage device connected to the sensor terminal unit 406, and the data is processed for image display. The display unit 4 can be input from the display lead terminal unit 405 to the display unit.
02 is a system that projects video. Alternatively, a memory circuit or the like may be formed on the same substrate, and these systems may be performed on the same substrate. Then, the moving image or still image captured by the sensor unit is displayed on the liquid crystal panel almost in real time. Also,
The display unit may be configured to be able to display data from outside the apparatus.

FIG. 4B is a simplified diagram of a cross-sectional structure taken along the line AB in FIG. The element substrate 400 is bonded to the counter substrate 401 with a sealant 407, and a liquid crystal material 410 is sandwiched therebetween. The image is provided to the user using the light incident on the liquid crystal display surface.

In the present invention, an optical signal passing through the optical system 409 and the color filter 411 mounted on the back surface and further passing through the substrate 400 is detected by the sensor unit. Therefore, the substrate 400 used in the present invention is preferably a substrate having extremely excellent transparency with respect to visible light.

A cross-sectional view of one pixel constituting the display unit and sensor unit 402 in FIG. 4 is shown in FIG. 1, and an example of an arrangement using such elements is shown in FIG.

FIG. 2A shows a top view, and a cross-sectional view taken along line AB corresponds to FIG. FIG. 2 (A)
Then, the sensor part is covered with the reflective electrode 121. In FIG. 2A, the wiring 106,
The reflective electrode 121 is not formed on the 107, 115, and 116. This reflective electrode 12
1 is used to display the liquid crystal. Here, the wirings involved in the liquid crystal display are the pixel portion TFT signal line 115 and the pixel portion TFT gate line 106.

On the other hand, FIG. 2B shows the back surface of FIG. Actually, since the TFT protective light-shielding films 104 and 105 are formed, the TFT portion cannot be observed, but for the sake of convenience, only the portions where the light-shielding films 104 and 105 are formed are shown. In addition, the wiring 106, 107,
The photoelectric conversion layer 118 may be formed over the 115 and 116 and the pixel TFT, but FIG.
Thus, the photoelectric conversion layer 118 is not formed. The optical signal incident on the photoelectric conversion layer is read, and data is sent to the sensor unit TFT signal line 116. Here, the wirings involved in image reading are the sensor unit TFT signal line 116 and the sensor unit TFT gate line 107.

That is, according to the present invention, as shown in FIG. 1 or FIG. 2, the pixel pitch and the number of bits of the light receiving matrix and the display matrix are the same because two TFTs are provided in one pixel. A light shielding film 104 is provided on the substrate 100 on the display element side, and the TFT is protected from light incident from the back surface. The light shielding film 1 is applied to the TFT on the sensor element side.
05 may be provided. The light shielding film may be provided directly on the back surface of the substrate.

After the base film 101 is formed on the light shielding films 104 and 105, a plurality of TFTs for performing display or image reading are formed. The back surface of the substrate here refers to the substrate surface on which TFTs are not formed. Further, the structure of this TFT may be a top gate type TFT or a bottom gate type TFT.

Then, a transparent conductive film 117 connected to the drain electrode 112 of the TFT on the sensor element side is provided. This conductive film is a film that forms the lower electrode of the photoelectric conversion element, and is formed in a pixel region other than the upper part of the TFT of the display element. A photoelectric conversion layer is provided on this conductive film, and an upper electrode 119 is further provided thereon, thereby completing a photoelectric conversion element.

On the other hand, the TFT on the display element side is provided with a pixel reflection electrode 121 connected to the drain wiring 114. The pixel reflection electrode may be configured to cover the sensor portion and the wiring. When the wiring is covered, a capacitor is formed using an insulating film existing between the wiring and the pixel reflection electrode as a dielectric. Since the present invention is a reflective display, a metal material having reflectivity is used for the pixel electrode.

The manufacturing process of the present invention is substantially the same as the manufacturing process of the conventional display device except for the manufacturing process of the photoelectric conversion element. Therefore, since the conventional manufacturing process can be used, it can be manufactured easily and inexpensively. In addition, the device manufactured according to the present invention is not changed in shape and size from the conventional panel even if the sensor function is mounted. Therefore, it can be reduced in size and weight.

Examples of the present invention will be described below, but the present invention is of course not limited to these examples.

In this embodiment, a manufacturing process example of a liquid crystal panel having a sensor portion that receives light from the back surface of the liquid crystal display surface will be described in detail with reference to FIGS.

First, the base film 101 is formed on the entire surface of the transparent substrate 100. As the transparent substrate 100, a transparent glass substrate or quartz substrate can be used. Plasma CVD as the base film
A silicon oxide film was formed to a thickness of 150 nm by the method. In this embodiment, a light shielding film 104 for protecting the display pixel portion TFT from light from the back surface and a light shielding film 105 for protecting the light receiving sensor portion TFT from light from the back surface are provided before the base film forming step. It was. In this embodiment, a light shielding film is provided to prevent noise and deterioration. However, if the aperture ratio is given priority, there is no need to provide it.

Next, an amorphous silicon film is formed to 30 to 100 nm, preferably 30 nm by plasma CVD.
A polycrystalline silicon film was formed by irradiating an excimer laser beam. As a method for crystallizing the amorphous silicon film, a thermal crystallization method called SPC, an RTA method for irradiating infrared rays,
A method of using thermal crystallization and laser annealing may be used.

Next, the polycrystalline silicon film is patterned to form an island-shaped semiconductor layer 102 that constitutes the source region, the drain region, and the channel formation region of the TFTs 200 and 300. Then, a gate insulating film 103 that covers these semiconductor layers is formed. Gate insulating film is silane (SiH ₄ ) and N
₂ O is used as a source gas and is formed to a thickness of 100 nm by plasma CVD. [Fig. 5 (A
)]

Next, a conductive film is formed. Here, aluminum is used as a conductive film material, but a film containing titanium or silicon as a main component or a stacked film thereof may be used.
In this embodiment, the aluminum film is formed by sputtering to a thickness of 200 to 500 nm, typically 3
Formed at 00 nm. In order to suppress generation of hillocks and whiskers, the aluminum film contains scandium (Sc), titanium (Ti), and yttrium (Y) in an amount of 0.04 to 1.0% by weight.

Next, a resist mask is formed, the aluminum film is patterned to form an electrode pattern, and a pixel gate electrode 106 and a sensor portion gate electrode 107 are formed.

Next, an offset structure is formed by a known method. Furthermore, LDD is performed by a known method.
A structure may be formed. [Fig. 5 (B)]

Then, a first interlayer insulating film 113 is formed, and contact holes reaching the N-type high concentration impurity regions (source region and drain region) are formed. Thereafter, a metal film is formed and patterned to form wirings 112, 114, 115, and 116.

In this embodiment, the first interlayer insulating film 113 is formed of a silicon nitride film having a thickness of 500 nm. In addition to the silicon nitride film, a silicon oxide film or a silicon nitride film can be used as the first interlayer insulating film. Further, a multilayer film of these insulating films may be used.

In this embodiment, a laminated film made of a titanium film, an aluminum film, and a titanium film is formed as a metal film to be a wiring starting film by sputtering. Each of these film thicknesses is 100 nm,
300 nm and 100 nm.

Through the above process, the pixel TFT 200 and the light receiving portion TFT 300 are completed simultaneously. [
FIG. 5 (C)]

Next, a transparent conductive film is formed on the first interlayer insulating film 113 in contact with the drain wiring 112 of the light receiving portion TFT. A transparent conductive film is formed, patterned, and transparent electrode 117 of the photoelectric conversion element.
Form. ITO or SnO ₂ can be used for the transparent conductive film 117. In this embodiment, an ITO film having a thickness of 100 nm is formed as the transparent conductive film.

A general active image sensor is different from the image sensor of this embodiment in that the lower electrode is formed of a transparent conductive film, whereas the upper electrode is formed of a transparent conductive film. In the present invention, in order to receive light from the back surface, the lower electrode is formed of a transparent conductive film. [Figure 5
(D)]

Next, an amorphous silicon film 118 containing hydrogen (hereinafter referred to as a-S) functioning as a photoelectric conversion layer.
i: H film) is formed on the entire surface of the substrate. Then, patterning is performed so that the a-Si: H film remains only in the light receiving portion, thereby forming a photoelectric conversion layer.

Next, a conductive film is formed over the entire surface of the substrate. In this embodiment, a titanium film having a thickness of 200 nm is formed as the conductive film by a sputtering method. The conductive film is patterned to form an upper electrode 119 connected to the light receiving portion TFT. Titanium or chromium can be used as the conductive film. [
FIG. 6 (A)]

The light receiving effective portions of the sensor unit are gate wirings 106 and 107 and signal wirings 115 and 116.
This is a place where the light shielding films 104 and 105 in one pixel surrounded by are not formed. The pixel size in this embodiment is the same for the display unit and the sensor unit, and is set to 60 × 60 μm.
If it is the range of 16 micrometers-70x70 micrometers, it will not specifically limit.

Then, a second interlayer insulating film 120 is formed. It is preferable to form a resin film of polyimide, polyamide, polyimide amide, acrylic, or the like as the insulating film constituting the third interlayer insulating film because a flat surface can be obtained. Alternatively, a laminated structure may be used, and the upper layer of the third interlayer insulating film may be the above-described resin film, and the lower layer may be a single layer or a multilayer film of an inorganic insulating material such as silicon oxide, silicon nitride, or silicon oxynitride. In this example, a 0.7 μm-thick polyimide film was formed on the entire surface of the substrate as an insulating film. [Fig. 6 (B)]

Further, a contact hole reaching the drain wiring 114 is formed in the second interlayer insulating film.
Again, a conductive film is formed over the entire surface of the substrate and patterned to form a pixel electrode 121 connected to the pixel TFT. In this embodiment, a titanium film having a thickness of 200 nm is formed as the conductive film by a sputtering method. Titanium, chromium, or aluminum can be used as the conductive film.

  Through the above steps, an element substrate as shown in FIG. 6C or FIG. 1 is completed.

Then, the element substrate and the counter substrate are bonded together with a sealing material, and liquid crystal is sealed to complete a reflective liquid crystal panel. The liquid crystal can be freely selected according to the operation mode of the liquid crystal (ECB mode, guest host mode). The counter substrate is configured by forming a transparent conductive film and an alignment film on a transparent substrate. In addition to this, a black mask and a color filter can be provided as necessary.

Subsequently, as shown in FIG. 4B, a color filter 411 is formed on the back surface of the liquid crystal panel.
Then, an optical system 409 and a support base 408 for mounting the optical system 409 are provided to manufacture a device.

Thus, a liquid crystal panel having a sensor portion that receives light from the back surface of the liquid crystal display surface is completed. For convenience, FIG. 3 shows a circuit diagram of this embodiment simplified to 2 × 2 pixels. The most characteristic point in this circuit diagram is that the liquid crystal display element and the sensor element are independent of each other.

The liquid crystal display element mainly includes a liquid crystal material 302, a capacitor 314, a pixel TFT 303, a gate line connected to the display gate driver 311, a display signal driver 310, a display input signal line 306, and a fixed potential line 304. It is configured.

The sensor elements mainly include a photodiode PD301, a sensor TFT 312, a sensor output signal line, a sensor horizontal shift register 308, and a sensor vertical shift register 309.
, And a fixed potential line 305.

In this embodiment, a manufacturing process example of a liquid crystal panel having a sensor portion that receives light from the back surface of the liquid crystal display surface will be described in detail with reference to FIGS.
One pixel has a display pixel portion TFT and a light receiving sensor portion TFT. An interlayer film is formed to cover these TFTs, a photoelectric conversion layer is provided thereon, and is connected to the light receiving sensor portion TFT. This is a feature of this embodiment. Therefore, compared with Example 1, the aperture ratio is large.

First, a base film 701 is formed on the entire surface of the transparent substrate. A glass substrate or a quartz substrate can be used as the transparent substrate 700. A silicon oxide film having a thickness of 200 nm was formed as a base film by plasma CVD. In this embodiment, the display pixel TFT is formed before the base film forming step.
A light shielding film 703 for protecting the light-receiving portion from the light from the back surface and a light-shielding film 706 for protecting the light receiving sensor TFT portion from the light from the back surface are provided.

Next, an amorphous silicon film is formed to 30 to 100 nm, preferably 30 nm by plasma CVD.
A polycrystalline silicon film was formed by irradiating an excimer laser beam. As a method for crystallizing the amorphous silicon film, a thermal crystallization method called SPC, an RTA method for irradiating infrared rays,
A method using thermal crystallization and laser annealing can be used.

Next, the polycrystalline silicon film is patterned to form an island-shaped semiconductor layer 702 that constitutes the source region, the drain region, and the channel formation region of the TFTs 800 and 900. Next, a gate insulating film 704 covering these semiconductor layers is formed. Gate insulating film is silane (SiH ₄ ) and N ₂
Using O as a source gas, it is formed to a thickness of 120 nm by plasma CVD. [FIG. 8 (A)
]

Next, a conductive film is formed. Here, aluminum is used as a conductive film material, but a film containing titanium or silicon as a main component or a stacked film thereof may be used.
In this embodiment, the aluminum film is formed by sputtering to a thickness of 300 to 500 nm, typically 3
Formed at 00 nm. In order to suppress generation of hillocks and whiskers, the aluminum film contains scandium (Sc), titanium (Ti), and yttrium (Y) in an amount of 0.04 to 1.0% by weight.

Next, a resist mask is formed, the aluminum film is patterned to form an electrode pattern, and gate electrodes 705 and 707 are formed.

Next, LDD structures 709 and 710 are formed by a known method. Further, an offset structure may be formed by a known method. Reference numerals 708 and 711 denote high-concentration impurity regions, and 712 denotes a channel region. [Fig. 8 (B)]

Then, a first interlayer insulating film 713 is formed, and contact holes reaching the N-type high concentration impurity regions (source region and drain region) are formed. Thereafter, a metal film is formed and patterned to form wirings 714, 715, 722, and 723.

In this embodiment, the first interlayer insulating film is formed of a silicon nitride film having a thickness of 500 nm. In addition to the silicon nitride film, a silicon oxide film or a silicon nitride film can be used as the first interlayer insulating film. Further, a multilayer film of these insulating films may be used.

In this embodiment, a laminated film made of a titanium film, an aluminum film, and a titanium film is formed by a sputtering method as a metal film that serves as a starting film for the wiring electrodes 714, 715, 722, and 723.
These film thicknesses are 100 nm, 300 nm, and 100 nm, respectively.

Through the above process, the pixel TFT 800 and the light receiving portion TFT 900 are completed simultaneously. [
FIG. 8 (C)]

Next, a second interlayer insulating film 716 that covers the TFT is formed. The main difference from Example 1 is that a photoelectric conversion layer formed in a later process can be widely formed by providing the second interlayer insulating film. By doing so, the light receiving area ((
(Opening ratio) can be increased. The second interlayer insulating film is preferably a resin film that cancels out unevenness in the lower layer and obtains a flat surface. As such a resin film, polyimide, polyamide, polyimide amide, or acrylic can be used. The surface layer of the second interlayer insulating film may be a resin film in order to obtain a flat surface, and the lower layer may be a single layer or a multilayer of an inorganic insulating material such as silicon oxide, silicon nitride, or silicon oxynitride. In this embodiment, a polyimide film is formed to a thickness of 1.5 μm as the second interlayer insulating film.

Next, after forming a contact hole reaching the wiring 723 of the light receiving portion TFT 900 in the second interlayer insulating film 716, a transparent conductive film is formed. ITO or SnO ₂ can be used for the transparent conductive film. In this embodiment, an ITO film having a thickness of 120 nm is formed as the transparent conductive film.

Next, the transparent conductive film is patterned, and the lower electrode 717 connected to the light receiving portion TFT 900 is used.
Form. [FIG. 8D]

Next, an amorphous silicon film 718 containing hydrogen (hereinafter referred to as a-S) functioning as a photoelectric conversion layer.
i: H film) is formed on the entire surface of the substrate. Then, patterning is performed so that the a-Si: H film remains only in the light receiving portion, thereby forming a photoelectric conversion layer.

Next, a conductive film is formed over the entire surface of the substrate. In this embodiment, a titanium film having a thickness of 200 nm is formed as the conductive film by a sputtering method. The conductive film is patterned to form an upper electrode 719 connected to the light receiving portion TFT. Titanium or chromium can be used as the conductive film.

The general active type image sensor is different from the image sensor of this embodiment in that the lower electrode is formed of a transparent electrode, whereas the upper electrode is formed of a transparent electrode. In the present invention, in order to receive light from the back surface, the lower electrode is formed of a transparent conductive film. [Fig. 9 (A
)]

Then, a third interlayer insulating film 720 is formed. As the insulating film constituting the third interlayer insulating film, it is preferable to form a resin film of polyimide, polyamide, polyimide amide, acrylic, or the like because a flat surface can be obtained. Alternatively, the surface layer of the third interlayer insulating film may be the above resin film, and the lower layer may be a single layer or a multilayer film of an inorganic insulating material such as silicon oxide, silicon nitride, or silicon oxynitride. In this example, a polyimide film having a thickness of 0.5 μm was formed on the entire surface of the substrate as an insulating film. [Fig. 9 (B)]

The maximum process temperature of the present invention after polyimide film formation is the heat resistant temperature of this polyimide 3
The temperature is lower than 20 ° C.

Further, a contact hole reaching the wiring is formed in the third and second interlayer insulating films. A conductive film is formed again on the entire surface of the substrate and patterned to form a pixel electrode 721 connected to the pixel TFT. In this embodiment, a titanium film having a thickness of 200 nm is formed as the conductive film by a sputtering method. Titanium or chromium can be used as the conductive film.

  Through the above steps, an element substrate as shown in FIG. 9C or FIG. 7 is completed.

Thereafter, as in Example 1, the element substrate and the counter substrate are bonded together with a sealing material, and a liquid crystal is sealed to complete a reflective liquid crystal panel. On the back surface of the liquid crystal panel, a color filter 411 and An optical system 409 and a support base 408 for mounting the optical system 409 are provided to manufacture the apparatus.

  Thus, a liquid crystal panel having a sensor portion that receives light from the back surface of the liquid crystal display surface is completed.

In Examples 1 and 2, an example using a non-amplification type image sensor was shown, but in this example,
More specifically, an example using an image sensor in which semiconductor devices are arranged in a matrix will be described with respect to an amplification type image sensor.

FIG. 10 shows a simplified circuit diagram of a liquid crystal panel using this amplification type image sensor. The amplification type image sensor uses three TFTs of a reset transistor T ₁ , an amplification transistor T _2, and a selection transistor T ₃ . The most characteristic point in this circuit diagram is that it has a reset line 1012, a power supply line 1113, a sensor vertical peripheral drive circuit 1009, a sensor horizontal peripheral drive circuit 1008, and a fixed potential line 1115.

Further, the present embodiment is characterized in that the wiring of the liquid crystal display element and the wiring of the sensor element are independent from each other as in the first or second embodiment. The liquid crystal display element includes a liquid crystal 1002 and a pixel TF.
It includes a T1003, a capacitor 1114, a fixed potential line 1004, a gate line connected to the display gate driver 1011, a display signal driver 1010, and a display input signal line 1006.

The general active type image sensor is different from the image sensor of this embodiment in that the lower electrode is formed of a transparent electrode, whereas the upper electrode is formed of a transparent electrode.

In the operation method of the image sensor of this embodiment, when an image for one frame is detected, a reset pulse signal is input from the reset line 1012 and the reset transistor T ₁ having the reset line as a gate is turned on. Then, the potential of the upper electrode of the photodiode and the amplification transistor are reset to the power supply potential. When the reset transistor T ₁ is in the off state, the gate electrode of the amplification transistor T ₂ is in a floating state. In this state, the photodiode P
The incident light in D1001 is converted into electric charge and accumulated. This electric charge slightly changes the potential of the upper electrode of the photodiode from the power supply potential. This variation in potential is detected as the potential variation of the gate electrode of the amplifying transistor T _2, the drain current of the amplifying transistor T ₂ is amplified. When a selection pulse signal is input from the selection line 1116, the selection transistor T
₃ is turned on, and the current amplified in the amplification transistor T ₂ is output to the signal line 1007 as a video signal.

In this embodiment, an example of an apparatus including an integrated liquid crystal display panel having an image sensor function as shown in Embodiments 1 to 3 will be described.

Here, an example of a digital still camera as shown in FIGS. 11A and 11B is shown. FIGS. 11A and 11B show the case where the viewing angle is changed by 180 degrees.

11A and 11B includes a light receiving unit 1102 in which a main body 1101 includes a display unit 1106 and an image sensor disposed on the back surface thereof, an operation switch 1105, a shutter 1104, and a flash 1103. Yes.

The image captured by the image sensor of the light receiving unit 1102 is subjected to signal processing, and a still image or a moving image is displayed or taken into memory in real time.

Here, an example of a mobile phone having a sensor function as shown in FIGS. 11C and 11D is shown. FIGS. 11C and 11D show cases where the viewing angles are varied by 180 degrees.

11C and 11D includes a light receiving portion 1112 in which a main body 1111 is provided with a display portion 1117 and an image sensor arranged on the back surface thereof, and an operation switch.

The image captured by the image sensor of the light receiving unit 1112 is subjected to signal processing, and a still image or a moving image is displayed on the display unit 1117 in real time. In addition, image data is received from a communication partner and displayed. Further, the image data captured by the image sensor of the light receiving unit 1112 may be captured in a memory and transmitted to the communication partner.

DESCRIPTION OF SYMBOLS 100 Substrate 101 Base film 102 Island-like semiconductor layer 103 Gate insulating film 104 Light-shielding film (pixel portion TFT)
105 Light shielding film (Sensor TFT)
106 Gate electrode (pixel TFT)
107 Gate electrode (Sensor TFT)
108 Source region (high concentration impurity region)
109 Drain region 110 Channel region 112 Drain electrode (sensor part)
113 First interlayer insulating film 114 Source wire (electrode)
115 Signal line (pixel part)
116 Signal line (sensor part)
117 Transparent conductive film (lower electrode)
118 Photoelectric conversion layer 119 Upper electrode 120 Second interlayer insulating film 121 Pixel electrode 200 Display pixel unit 300 Light receiving sensor unit 700 Substrate 701 Base film 702 Island-like semiconductor layer 703 Gate insulating film 704 Light shielding film (pixel unit TFT)
705 Gate electrode (pixel TFT)
706 Light shielding film (Sensor TFT)
707 Gate electrode (Sensor TFT)
708 source region (high concentration impurity region)
709 Low concentration impurity region 710 LDD region (low concentration impurity region)
711 Drain region 712 Channel region 713 First interlayer insulating film 716 Second interlayer insulating film 717 Transparent conductive film (lower electrode)
718 Photoelectric conversion layer 719 Upper electrode 720 Third interlayer insulating film 721 Pixel electrode 800 Display pixel portion 900 Light receiving sensor portion

Claims (1)

The first substrate, the display unit and the sensor unit on the surface of the first substrate, the second substrate facing the surface of the first substrate, and the first substrate and the second substrate are bonded together. A sealing material, and a liquid crystal material between the first substrate and the second substrate,
The display portion includes a first transistor having a first island-shaped semiconductor layer, a first wiring electrically connected to the first island-shaped semiconductor layer, and an electrical connection to the first wiring. A pixel electrode connected to
The sensor unit includes a second transistor having a second island-shaped semiconductor layer, a second wiring electrically connected to the second island-shaped semiconductor layer, and a photoelectric conversion element. ,
The photoelectric conversion element has a third electrode made of a transparent conductive film, a photoelectric conversion layer, and a fourth electrode .
Has an interlayer insulating film before Symbol first wiring and the second on the wiring,
It said third electrode made of a transparent conductive film, a liquid crystal display device comprising a benzalkonium electrically connected to the second wiring through a contact hole formed in the interlayer insulating film.

Images