JPH06110080A - Active matrix substrate and production of active matrix substrate - Google Patents

Abstract

PURPOSE:To provide a bright and high contrast and high image quality free from flickers and crosstalks by forming pixel electrodes formed of transparent conductive films in selfalignment to wirings for operating nonlinear elements. CONSTITUTION:A photosensitized org. thin film is removed by an org. solvent to expose the light transparent conductive films. The exposed light transparent conductive films are then irradiated with particles 617 of high energy, for example, oxygen plasma or oxygen ions, by which the electric conductivity of the light transparent conductive films is changed. The components of the light transparent conductive film are excessive with the oxygen and the films 618 having the electrically high resistance are obtd. if the light transparent conductive films are, for example, indium tin oxide films. The light transparent conductive films of the region coated with the photosensitized org. thin films are not irradiated with the particles 617 of the high energy and, therefore, the electrical conductivity is high. Consequently, the light transparent conductive films turn to the pixel electrodes 721 to 723 electrically insulated with each of the picture elements.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly to a liquid crystal display device having a non-linear element.

[0002]

2. Description of the Related Art Active matrix liquid crystal displays, which are influential flat displays, have begun to be mass-produced. The flat display occupies a small space,
Due to its light weight, it is used for display devices of portable computers and display parts of industrial machines. In the future, the screens will become larger and the definition will become higher, and it is expected that home-use televisions will be applied. In the case of a liquid crystal display using a thin film transistor as a driving element, it is necessary to increase the aperture ratio of each pixel for high contrast and color reproducibility, and to prevent screen flicker. As shown in FIG. 8, the conventional pixel layout has a certain distance between the gate line 804 and the data line 809 so that the pixel electrode 824 electrically connected to the drain region 806 of the thin film transistor T does not overlap in plan view. It had been formed. Further, a light shielding film is formed on the counter substrate of the active matrix substrate so that light does not leak from the gaps between the pixel electrode 824 and the gate lines 804 and the data lines 809. Therefore, the effective aperture area through which light is transmitted is a portion surrounded by the solid line 825 in FIG. 8, and the effective area of the pixel is about 30%, which causes a problem that the screen has low illuminance.

A conventional good example for overcoming the problem of the small aperture ratio is Japanese Patent Laid-Open Publication No. 2-207222.
FIG. 4 shows a layout of drive elements and pixels of the active matrix liquid crystal display device with the increased aperture ratio of the conventional example. In this conventional active matrix type liquid crystal display device, in order to increase the aperture ratio, an organic thin film interlayer insulating film is formed between the transparent pixel electrode 924 and the gate line 904, and between the pixel electrode 924 and the data line 909, The electrode 924 was formed so as to overlap with both the gate line 904 and the data line 909.

FIG. 10 is a sectional view taken along the line AB of FIG.
Shown in.

In Japanese Laid-Open Patent Publication No. 2-207222, an inverted stagger type thin film transistor is used as a switching element of a pixel electrode. However, even with a planar type thin film transistor, the essence of the conventional example does not change. A conventional example will be described with reference to a thin film transistor. A passivation film 1002 for preventing diffusion of impurities is formed on the glass substrate 1001, and the source region 100 is formed.
5 drain region 1006 and active silicon layer 1007 are continuously formed, a gate insulating film 1003 is deposited on the active silicon layer 1007, and the active silicon layer 10 is further formed.
There is a gate electrode 1004 so as to overlap 07. The gate electrode 1004 is covered with a first interlayer insulating film 1008 and a second interlayer insulating film 1010. In addition, the first interlayer insulating film 10
There is a source electrode connected to the source region 1005 between 08 and the second interlayer insulating film 1010. Further, contact holes are formed in the interlayer insulating film so as to reach the drain region 1006, and pixel electrodes 1021, 1022, and 1023 are formed on the second interlayer insulating film 1010. Figure 1
0, the pixel electrodes 1021, 1022, 10
23 is formed so as to overlap the gate electrode 1004. That is, on the gate electrode and the gate line of the thin film transistor 1019, part of the pixel electrode 1021 of the thin film transistor 1019 and the adjacent thin film transistor 1020 are provided.
Part of the pixel electrodes 1022 of the above overlapped each other. Further, as shown in the layout of FIG. 9, the data line and the pixel electrode also partially overlap each other like the gate line.

[0006]

However, the conventional method disclosed in Japanese Patent Laid-Open No. 2-207222 has the following problems.

Between the data line and the transparent pixel electrode, 40
A silicon oxide film or a silicon nitride film having a thickness of 0 nm or an organic thin film having a thickness of 1000 nm is sandwiched between the data line and a part of the transparent pixel electrode, and the gate line and a part of the transparent pixel electrode. Again,
Although the aperture ratio is improved, a large parasitic capacitance is generated between the gate line and the pixel electrode, a sufficient signal is not applied to the transparent pixel electrode, and a low-contrast display is obtained. There were drawbacks and signal delay issues. Further, the parasitic capacitance generated between the data line and the pixel electrode causes a crosstalk due to a delay or rounding of a signal on the data line, which causes a serious problem that a high quality image cannot be obtained.

[0008]

In an active matrix substrate of a liquid crystal display device in which a liquid crystal is sandwiched between two transparent substrates and a non-linear element is formed on at least one substrate, a pixel formed by a transparent conductive film. The active matrix substrate is characterized in that the electrodes are formed in a self-aligned manner with respect to the wiring for operating the nonlinear element.

Further, a non-linear element and a transparent conductive film for controlling the non-linear element are formed on the transparent substrate by depositing a transparent conductive film on the substrate, and a photosensitive film is deposited on the transparent conductive film. Then, by irradiating light from the surface of the transparent substrate on which the non-linear element is not formed, the photosensitive film on the transparent conductive film is exposed according to the light-shielding wiring, and the photosensitive film in the non-exposed area is transparent. A method for manufacturing an active matrix substrate, which comprises a step of removing the conductive film from the conductive film and applying energy particles to the transparent conductive film in a region not covered by the photosensitive film to lose the conductivity.

In view of the above problems, the present invention reduces the parasitic capacitance generated between the gate line and the pixel electrode, which causes the pushdown, and also occurs between the wiring and the pixel electrode, which causes the crosstalk. The present invention provides a structure of an active matrix substrate which constitutes a liquid crystal display body capable of obtaining a clear and high-quality image by reducing the parasitic capacitance and a manufacturing method thereof.

[0011]

EXAMPLE FIG. 1 is a plan view of a pixel of an example. The gate lines 104, which also serve as the gate electrodes of the thin film transistors, and the data lines 109 are arranged in a grid pattern, and the thin film transistors T are formed at the intersections thereof. Data line 10
9 is electrically connected to the source region 105 of the thin film transistor T, and the pixel electrode 124 is electrically connected to the drain region 106. The pixel electrode 124 is formed in a region where the wiring of the gate line 104 and the data line 109 is not formed, and there is no plane gap between the pixel electrode 124, the gate line 104, and the data line 109. Therefore, when light is incident from the back surface of the active matrix substrate, the gate lines 104 and the data lines 109 also serve as light-shielding films, so that the light-shielding film of the counter substrate, which is required in the conventional liquid crystal display device, is eliminated, and an effective pixel area is formed. Increase significantly.

Further, FIGS. 9 and 10 without the need for a light-shielding film.
Unlike the conventional example, the gate line 104 and the data line 1
09 and the pixel electrode 124 are not superposed, the parasitic capacitance generated between the gate line and the pixel electrode and the parasitic capacitance generated between the data line and the pixel electrode are extremely small, so that crosstalk and pushdown are performed. The phenomenon does not occur. Therefore, the liquid crystal display device manufactured by using the active matrix substrate having the structure of the present invention can realize a high quality image which is bright and has a high contrast without flicker or crosstalk.

Next, referring to FIGS. 2 to 7,
The method of manufacturing the active matrix substrate of the present invention will be described in detail.

First, as shown in FIG. 2, a passivation film 202 made of a nitride film or an oxide film is formed on a transparent substrate 201 such as glass so as to prevent impurity diffusion. Next, a patterned silicon film is deposited on the insulating film 202, and the insulating film 2 made of an oxide film is formed.
Form 03. Next, a gate line 204 made of a patterned light-shielding conductive film is formed so as to overlap the silicon film. The gate line 204 also serves as the gate electrode of the thin film transistor T of FIG. Next, impurities are ion-implanted into the silicon film in a self-aligned manner with respect to the gate line 204, and the source region 205 and the drain region 2
06 is formed. Source region 204 and drain region 20
An area between 5 is an active silicon layer 207.

Further, a first interlayer insulating film 208 is deposited so as to cover the gate line 204, and a data line 209 made of a light-shielding conductive film is electrically connected to the source region 205 through a contact hole. Furthermore, the second
An interlayer insulating film 210 is formed so as to cover the data line 209, and further, a light-transmissive conductive film is formed so as to be electrically connected to the drain region 206 through a contact hole, for example, indium formed by a sputtering method. A soot oxide film 211 is deposited on the entire surface of the substrate.

Next, as shown in FIG. 3, a photosensitive organic thin film 31 is formed on the light-transmissive conductive film 211 formed in FIG.
2 is formed on the entire surface of the substrate.

Next, as shown in FIG. 4, light 413 is irradiated from the side of the substrate on which the organic thin film is not formed. Then, the light-shielding gate line 404 and the data line 409 are provided.
Since the organic thin film in the region where the pixel is not formed is exposed to light, it becomes the exposed organic thin film 414, and the organic thin film in the region overlapping the gate line 404 and the data line 409 is not exposed and remains as it is. Further, if the thickness of the silicon layer in the drain region is 40 nm, 300 to 400 n
Since the light of m is sufficiently transmitted, the organic thin film on the drain region is also exposed.

Next, as shown in FIG. 5, the exposed organic thin film is removed with an organic agent to expose the light-transmissive conductive film. Reference numeral 516 denotes an area where the light transmitting film is exposed.

Next, as shown in FIG. 6, the exposed light-transmissive conductive film 6 is irradiated with high-energy particles 617, for example, oxygen plasma or oxygen ions, so that the light-transmissive conductive film 6 is exposed.
Change the conductivity of 11. By this treatment, for example, when the light-transmissive conductive film is an indium tin oxide film, the component of this film becomes oxygen excess, and several tens Ωcm ⁻¹ to several kΩ.
The film 618 has a cm ^-1 electrically high resistance. The light-transmitting conductive film in the region covered with the exposed organic thin film 614 has high conductivity because the high-energy particles 617 are not hit.

As a result, as shown in FIG. 7, the light-transmissive conductive film is formed in the pixel electrode 72 which is electrically insulated for each pixel.
1, 722, 723.

By the above manufacturing method, the pixel electrode 124 can be formed in self-alignment with the gate line 104 and the data line 109 as shown in FIG. 1, so that the effective pixel area is remarkably increased. can do.

Since the wiring and the pixel electrode do not overlap each other and a second interlayer insulating film made of a low dielectric constant organic thin film having a thickness of 1 to 2 μm is formed between the wiring and the pixel electrode. Since the generation of parasitic capacitance between the wiring and the pixel electrode is extremely small, the distortion of the signal applied to the pixel electrode is eliminated, the contrast is high, and a clear high-quality image without flicker or crosstalk can be obtained. became.

In this embodiment, the pixel electrode is made of indium
Although it is a tin oxide film, the present invention is not limited to this material, and the present invention can be applied to any film as long as its electric property is changed by irradiation of high energy particles.

Further, the interlayer insulating film between the wiring and the pixel electrode is not limited to the organic thin film, and may be a silicon oxide film or a silicon nitride film.

[0025]

As shown in FIG. 1, since the pixel electrodes can be formed in a self-aligned manner with respect to the gate lines and the data lines, the effective pixel area can be remarkably increased, so that a bright image can be obtained. Has come to be obtained.

Further, since the wiring and the pixel electrode do not overlap each other and the organic thin film having a low dielectric constant and a thickness of 1 to 2 μm is formed between the wiring and the pixel electrode, the parasitic capacitance between the wiring and the pixel electrode. Is extremely small, the distortion of the signal applied to the pixel electrode is eliminated, the contrast is high, and a clear high-quality image without flicker or crosstalk can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view of an active matrix substrate of the present invention.

FIG. 2 is a manufacturing diagram of an active matrix substrate of the present invention.

FIG. 3 is a manufacturing diagram of an active matrix substrate of the present invention.

FIG. 4 is a manufacturing diagram of an active matrix substrate of the present invention.

FIG. 5 is a manufacturing diagram of an active matrix substrate of the present invention.

FIG. 6 is a manufacturing drawing of the active matrix substrate of the present invention.

FIG. 7 is a manufacturing diagram of an active matrix substrate of the present invention.

FIG. 8 is a plan view of a conventional active matrix substrate.

FIG. 9 is a plan view of a conventional active matrix substrate.

FIG. 10 is a sectional view of a conventional active matrix substrate.

[Explanation of symbols]

T ... Thin film transistor 201, 1001 ... Glass substrate 202, 1002 ... Passivation film 203, 1003 ... Gate insulating film 104, 204, 404, 804, 904, 1004 ... Gate electrode and gate line 105, 205, 805, 905, 1005 ... Source Regions 106, 206, 806, 906, 1006 ... Drain regions 207, 1007 ... Active silicon regions 208, 1008 ... First interlayer insulating films 109, 209, 409, 809, 909, 1009 ... Source electrodes and data lines 210, 1010 Second interlayer insulating film 211 Transparent conductive film 312 Photosensitive film 413 Light 414, 614 Photosensitive film 415 Photosensitive film 516 Not exposed Photosensitive film 516 Area where transparent conductive film is exposed 617 High Irradiation of high-energy particles 618 High-resistivity film formed by irradiation of high-energy particles 719, 1019 First thin film transistors 720, 1020 Second thin film transistors 721, 1021 next to the first pixel electrode 722 of the first thin film transistor , 1022 ... the second thin Pixel electrode of transistor 723, 1023 ... Pixel electrode next to second thin film transistor 124, 824, 924 ... Pixel electrode 825 ... Region where no light-shielding film is formed on counter substrate 926 ... Overlap portion of gate line and pixel electrode 927 ... Overlap of data line and pixel electrode

Claims (2)

[Claims] 1. In an active matrix substrate of a liquid crystal display device in which a liquid crystal is sandwiched between two transparent substrates, and a non-linear element is formed on at least one of the substrates, a pixel electrode formed by a transparent conductive film has the non-linearity. An active matrix substrate, which is formed in a self-aligned manner with respect to wiring for operating an element. 2. A transparent conductive film is deposited on a transparent substrate on which a non-linear element and a light-shielding wiring for controlling the non-linear element are formed, and a photosensitive film is deposited on the transparent conductive film. Then, by irradiating light from the surface of the transparent substrate on which the non-linear element is not formed, the photosensitive film on the transparent conductive film is exposed according to the light-shielding wiring, and the photosensitive film in the non-exposed area is transparent. A method for manufacturing an active matrix substrate, which comprises a step of removing energy from the conductive film and applying energy particles to the transparent conductive film in a region not covered by the photosensitive film to lose conductivity.