JP2001337347A - Liquid crystal display device and method of manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a display defect when a color filter is formed on an active matrix substrate. SOLUTION: An Ar reverse sputtering having <=8,000 J energy is performed to colored layers 6a-6c in which through holes 7 are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a method of manufacturing the same, and more particularly, to a liquid crystal display device having a color filter (also referred to as a colored layer) laminated on an active matrix substrate and a method of manufacturing the same. It is suitable.

[0002]

2. Description of the Related Art In a conventional liquid crystal display device, two electrode substrates having an alignment film formed thereon are arranged at a predetermined interval so that the alignment films are opposed to each other, and a liquid crystal layer is interposed between the two electrode substrates. Is provided. These two electrode substrates are bonded together by a sealing material and a sealing material disposed in a peripheral region thereof, and a spacer pillar made of a particulate spacer or a resin formed by photolithography is interposed between the two electrode substrates. , The distance between these two electrode substrates is kept constant.

When a color display is performed on a liquid crystal display device, a colored layer composed of red R, green G, and blue B is disposed on one of the electrode substrates, and a transparent protective film made of a resin is provided on the colored layer or the switching element as necessary. Formed on a substrate having

Here, in order to prevent the influence of misalignment with the counter substrate and increase the aperture ratio, a colored layer is formed on the active matrix substrate.

[0005] In this configuration, a coloring layer is provided between the switching element formed on the active matrix substrate and the pixel electrode formed on the active matrix substrate to ensure conduction between the switching element and the pixel electrode. Therefore, through holes are formed in the colored layer.

[0006]

However, in the method of forming a through hole in the colored layer to ensure conduction between the switching element and the pixel electrode, if the material of the colored layer remains in the through hole as a residue, the contact failure occurs. This causes a problem of display failure.

Further, when a colored layer is laminated on an active matrix substrate, there is a problem that display unevenness and image sticking occur due to a colored layer material which is in direct contact with an alignment film and a liquid crystal layer.

An object of the present invention is to provide a liquid crystal display device capable of suppressing display defects when a color filter is formed on an active matrix substrate, and a method of manufacturing the same.

[0009]

According to the first aspect of the present invention, a switching element is formed on an array substrate corresponding to an intersection between a signal line and a scanning line. Forming a colored layer on the switching element so as to cover at least a part of the switching element; forming a through hole in the colored layer; and coloring the through hole. A step of performing reverse sputtering with an energy of 8000 J or less on the layer, a step of forming a pixel electrode on the colored layer in which the through-hole is formed, and disposing a counter substrate facing the array substrate at a predetermined interval. And a step of sealing liquid crystal between the array substrate and the counter substrate.

[0010] This makes it possible to remove the coloring layer material remaining as a residue in the through hole while suppressing the decomposition of the coloring layer due to reverse sputtering, and to remove impurities contained in the coloring layer from the alignment film and the liquid crystal layer. It is possible to suppress the elution of the sapphire, and it is possible to reduce the contact failure, and it is possible to reduce the occurrence of the uneven alignment and the burning phenomenon.

According to the third aspect of the present invention, an active matrix substrate in which switching elements are formed in a matrix corresponding to intersections between signal lines and scanning lines, and at least a part of the switching elements are provided. The surface layer formed by performing reverse sputtering with an energy of 8000 J or less on the colored layer formed so as to cover, the through hole formed in the colored layer, and the colored layer formed with the through hole. And a pixel electrode laminated on the coloring layer and electrically connected to the switching element through the through hole, and a counter substrate disposed to face the active matrix substrate at a predetermined interval. A spacer for holding the active matrix substrate and the counter substrate at the predetermined interval, and the active matrix substrate Characterized in that it comprises a liquid crystal layer provided between the counter substrate.

This makes it possible to remove the coloring layer material remaining as a residue in the through hole while suppressing the impurities contained in the coloring layer from being eluted into the alignment film and the liquid crystal layer. By performing surface modification, it is possible to improve the adhesion and processability of the pixel electrode formed on the colored layer, and it is possible to suppress display defects when the colored layer is formed on the active matrix substrate. Becomes

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a liquid crystal display according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view illustrating a schematic configuration of a liquid crystal display device according to an embodiment of the present invention. In FIG. 1, a TFT array substrate 1 includes a switching element 5 formed on a glass substrate 4, and a colored layer 6a is provided on the switching element 5.
To 6c are formed. Here, the colored layer 6a is blue B, the colored layer 6b is green G, the colored layer 6c is red R,
The end of the coloring layer 6b is covered with the coloring layer 6a and the coloring layer 6c. For the coloring layer material of the coloring layers 6a to 6c, for example, an ultraviolet curable acrylic resin is used.

Through holes 7 are formed in the colored layers 6a to 6c corresponding to the positions of the switching elements 5, and pixel electrodes 8 are formed on the colored layers 6a to 6c in which the through holes 7 are formed. ing. Also, on the pixel electrode 8,
So as to cover the pixel electrode 8 and the colored layers 6a to 6c,
An alignment film 9 is formed.

On the other hand, the counter substrate 2 includes a counter electrode 11 formed on a glass substrate 10, and the counter electrode 11 has
An alignment film 12 is formed.

Here, the pixel electrode 8 and the counter electrode 11
For example, a transparent electrode such as an ITO film can be used. In addition, as an alignment film material of the alignment films 9 and 12, for example, polyimide can be used.

The TFT array substrate 1 and the opposing substrate 2 are opposed to each other so that the alignment films 9 and 12 face each other, and a predetermined distance is provided by a spacer 13 disposed between the TFT array substrate 1 and the opposing substrate 2. Is held in.

Here, as the spacer 13, for example, a bead-shaped spacer or a resin-based spacer pillar formed by a photolithography method can be used.

A liquid crystal layer 3 is formed in a gap between the TFT array substrate 1 and the opposing substrate 2 and is sealed by a sealing material 14 provided between the TFT array substrate 1 and the opposing substrate 2. The sealing material 14 is arranged so as to surround the outer periphery of the substrate except for the liquid crystal injection port, and adheres the TFT array substrate 1 to the counter substrate 2. A sealing material is applied to the liquid crystal injection port. Here, as a sealing material of the sealing material 14, for example, a thermosetting epoxy-based adhesive can be used.

FIG. 2A shows the TFT array substrate 1 of FIG.
Top view showing a schematic configuration of a portion corresponding to the colored layer 6b of FIG.
FIG. 2B is a cross-sectional view taken along line AA in FIG. In FIG. 2, a scanning line 2 is provided on a glass substrate 4.
1a is arranged, and a gate electrode 21b is connected to the scanning line 21a. Here, for the scanning line 21a and the gate electrode 21b, for example, a MoW (molybdenum / tungsten) film can be used.

A gate insulating film 22 is formed on the scanning line 21a and the gate electrode 21b, and an amorphous silicon layer 23 is formed on the gate insulating film 22. The amorphous silicon layer 23 includes a channel layer 23a corresponding to the arrangement position of the gate electrode 21b and n ^{+ on} both sides thereof.
It has diffusion layers 23b and 23c. Then, on the ^{n +} diffusion layer 23b, the source electrode 25 is formed, on the ^{n +} diffusion layer 23c, the drain electrode 24b are formed, the drain electrode 24b is connected to a signal line 24a. Here, as the source electrode 25, the drain electrode 24b, and the signal line 24a, for example, a three-layer Mo / Al / Mo film can be used.

The gate electrode 21b, gate insulating film 22, channel layer 23a, n ⁺ diffusion layers 23b and 23c, source electrode 25 and drain electrode 24b constitute a TFT (thin film transistor) functioning as the switching element 5 in FIG. The scanning line 21a and the signal line 24a are arranged to intersect. The scanning line 21a and the signal line 24
The switching elements 5 are arranged in a matrix corresponding to the intersections of a.

On the switching element 5, a protective film 2
A colored layer 6b is formed through the layer 6. This colored layer 6
b are arranged in a stripe pattern and the colored layer 6b
, Through holes 7 are formed corresponding to the arrangement positions of the source electrodes 25. On the coloring layer 6b, a pixel electrode 8 is provided corresponding to the switching element 5, and the pixel electrode 8 is connected to the source electrode 25 via the through hole 7.

Here, Ar reverse sputtering is performed on the colored layers 6a to 6c in which the through holes 7 are formed, and the power of the Ar reverse sputtering is controlled to 5000 W / m ² or less. Thereby, it is possible to suppress the occurrence of defective through-holes and to prevent the elution of impurities from the coloring layers 6a to 6c, thereby suppressing the occurrence of display unevenness such as uneven alignment and printing.

FIG. 3 is a graph showing the dependence of the failure of the liquid crystal display device on the reverse sputtering energy of Ar according to the embodiment of the present invention. Here, an experiment was performed by irradiating ultraviolet rays, which are generally recognized as having an effect of removing residues from through holes, before reverse sputtering, and changing the irradiation conditions.

In FIGS. 3A to 3C, when no ultraviolet light is irradiated, the Ar reverse sputtering energy is set to 6000.
By setting J or more, the residue of the through hole can be removed. On the other hand, irradiation with ultraviolet light can remove through-hole residues even if the Ar reverse sputtering energy is smaller. For example, ultraviolet rays of 500 mJ / cm
^{When 2} irradiations are performed, the Ar reverse sputtering energy is 4000
It may be J or more.

On the other hand, in FIGS.
When the reverse sputtering energy is 8000 J or more, uneven alignment, image sticking and the amount of impurities rapidly increase.

Here, display unevenness caused by a material which is in direct contact with the liquid crystal layer or the alignment film, such as a color layer material, is caused by the fact that organic impurities in the color layer are eluted into the liquid crystal layer or the alignment film.
It has been found that this is due to the occurrence of uneven alignment and a printing phenomenon. That is, alkyl acids, phenylcarboxylic acids, phenylcarboxylic acid derivatives, phenylenedicarboxylic acids, phenylenedicarboxylic acid derivatives, alkylamines,
Aniline, aniline derivative, phenylenediamine, phenylenediamine derivative, phenyleneamine carboxylic acid,
Organic impurities such as a phenyleneamine carboxylic acid derivative and an alkyl imide were contained in the colored layer, which was found to be the cause.

Further, it was found that these impurities are contained in the pigment in the colored layer in a large amount. For example, the pigment used for the green coloring material of the color filter of the liquid crystal display device is a pigment of G7 or G86, which contains many impurities as described above.

Further, the dispersant for dispersing this in the colored paste also contains many impurities. Furthermore, it was found that the above-mentioned pigments and dispersants were decomposed at high temperatures, by contact with alkalis, or by exposure to ultraviolet rays, to generate the above-mentioned organic impurities. These become more severe by increasing the energy of Ar reverse sputtering. As a result, A
By setting the r reverse sputtering energy to 8000 J or less, uneven alignment, image sticking, and an increase in the amount of impurities can be suppressed.

Judging from the results shown in FIG. 3, by making the Ar reverse sputtering energy 8000 J or less, the occurrence of through-hole defects is suppressed, and the occurrence of display unevenness such as uneven alignment and image sticking is suppressed. can do.

On the other hand, irradiating a large amount of ultraviolet rays is effective in suppressing through-hole defects, but causes a temporal change in the threshold value of the TFT. Therefore, it is desirable to use a combination of ultraviolet rays and Ar reverse sputtering. .

Hereinafter, a method for manufacturing a liquid crystal display device according to an embodiment of the present invention will be described.

In manufacturing the TFT array substrate 1, 0.8 μm
A scanning line 21a and a gate electrode 21b are formed by depositing a molybdenum / tungsten film having a thickness of about m on the glass substrate 4 by a sputtering method and patterning the molybdenum / tungsten film using a photolithography technique.

Next, the scanning line 21a and the gate electrode 21
A gate insulating film 22 is formed on the glass substrate 4 on which b is formed. The gate insulating film 22 is made of, for example, plasma C
A silicon oxide film or a silicon nitride film by VD or the like can be used.

Next, the scanning line 21a and the gate electrode 21
An amorphous silicon film is deposited on the glass substrate 4 on which b is formed by a plasma CVD method, and the amorphous silicon film is patterned to form an amorphous silicon layer 23. Then, arsenic, phosphorus, or the like is ion-implanted into the amorphous silicon layer 23 on both sides of the gate electrode 21b, thereby forming the channel layer 23.
The n ⁺ diffusion layers 23b and 23c are formed on both sides of “a”.

Next, molybdenum (Mo), aluminum (Al) and molybdenum (Mo) are sequentially deposited and patterned to form a source electrode 25, a drain electrode 24b and a signal line 24a.

Next, the source electrode 25 and the drain electrode 24
b and the glass substrate 4 on which the signal line 24a is formed,
A UV-curable acrylic green resist solution is spin-coated. Subsequently, pre-baking is performed at about 90 ° C. for about 5 minutes, and 150 mJ / cm ² using a predetermined photomask pattern.
Exposure with ultraviolet light of intensity. The photomask pattern has a stripe pattern corresponding to the green coloring layer 6b and a diameter of 1 mm for forming the through hole 7.
It has a circular pattern of 5 μm. Subsequently, about 0.
Develop with a 1% by weight aqueous solution of TMAH (tetramethylammonium hydride) for about 60 seconds. And
After washing with water, post-baking is performed at about 200 ° C. for about 1 hour to form a green colored layer 6 b having through holes 7.

Subsequently, the blue coloring layer 6a and the red coloring layer 6c
Is formed in a similar process. At this time, the end of the pattern of the green coloring layer 6b is covered with the blue coloring layer 6a and the red coloring layer 6c. This is because each of the colored layers 6a to 6c
It can be achieved by manufacturing an exposure mask used for processing the silicon so as to be suitable.

Next, an ultraviolet ray is irradiated at 500 mJ / cm ² .

Next, reverse sputtering of Ar gas is performed at 200 W × 20 seconds = 4000 J using a usual method.

Next, a silicon oxide film or the like is formed as the protective film 26 by plasma CVD or the like, and an ITO film is deposited on the coloring layer 24 by a sputtering method. And
By patterning this ITO film, the pixel electrode 8
To form

Next, an alignment film material made of polyimide is applied to the entire surface of the substrate, and is subjected to an alignment treatment.
To form

Next, in the manufacture of the opposing substrate 2, an ITO film is deposited on the glass substrate 10 to a thickness of about 100 nm by sputtering to form the opposing electrode 11, and then an alignment film material made of polyimide is applied. The alignment film 12 is formed by coating the entire surface of the substrate and performing an alignment process.

Next, on the surface of the alignment film 12 of the counter substrate 2,
The granular spacers 13 having a diameter of about 5 μm are sprayed at a rate of about 100 pieces per 1 mm 2. Subsequently, a sealing material 14 in which a fiber having a predetermined size is mixed is applied to the periphery of the counter substrate 2 except for an injection port for injecting liquid crystal.

Next, the opposing substrate 2 and the TFT array substrate 1 are bonded to each other with a sealing material 14 interposed therebetween.
Form an empty cell.

Next, the liquid crystal layer 3 is formed by vacuum-injecting a nematic liquid crystal material to which the chiral material has been added into the cell from the injection port. Then, after the nematic liquid crystal material is injected, the injection port is sealed using an ultraviolet curable resin as a sealing material.

Next, a polarizing plate is arranged on each side of the cell.

The thus manufactured liquid crystal display element has no through-hole defect, suppresses elution of impurities from the colored layer, and reduces display unevenness such as uneven alignment and image sticking.

In the above-described example, a method is used in which granular spacers are scattered on the substrates as spacers for keeping a constant distance between the two substrates. A pattern having a predetermined thickness and thickness may be used as a spacer. At this time, as the resin layer,
A method in which the above colored layers are stacked and formed, or a transparent or black material may be used separately from the colored layers.
Further, these can be formed by using a photosensitive material or, in the case of a non-photosensitive material, by etching using a photosensitive resist.

[0051]

As described above, according to the present invention,
It is possible to reduce through-hole defects when a color filter is formed on an active matrix substrate, suppress elution of impurities from the colored layer, and suppress display unevenness such as uneven alignment and burn-in. Becomes

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2A is a top view showing a schematic configuration of an active matrix substrate according to one embodiment of the present invention, and FIG.
FIG. 2B is a sectional view taken along line AA in FIG.

FIG. 3 is a graph showing the dependence of a defect of a liquid crystal display device on reverse sputter energy according to an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 TFT array substrate 2 Counter substrate 3 Liquid crystal 4, 10 Glass substrate 5 Switching element 6a-6c Color filter 7 Through hole 8 Pixel electrode 9, 12 Alignment film 11 Counter electrode 13 Spacer 14 Seal material 21a Scanning line 21b Gate electrode 22 Gate insulation Film 23 amorphous silicon layer 23a channel layer 23b, 23cn ⁺ diffusion layer 24a signal line 24b drain electrode 25 source electrode 26 protective film

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Daisuke Miyazaki 1-9-2 Hara-cho, Fukaya-shi, Saitama Prefecture Inside the Toshiba Fukaya Plant (72) Inventor Jin Hitoshi 1-9-1-2 Harara-cho, Fukaya-shi, Saitama No. F-term in the Toshiba Fukaya Factory (reference) 2H091 FA02Y FC10 FC26 FD04 FD24 GA13 LA11 LA15 LA16 2H092 JA26 JA29 JA38 JA42 JA44 JA46 JB13 JB23 JB32 JB33 JB38 JB51 JB56 KA05 KA07 KA16 KA18 MA13 MA05 MA08 MA08 NA25 NA27 NA29 PA03 PA04 PA08 QA07 5C094 AA02 AA31 AA42 BA03 BA43 CA19 CA24 DA13 EA04 EA05 EA07 EB02 ED03

Claims (4)

[Claims] A step of forming a switching element on an array substrate corresponding to an intersection of a signal line and a scanning line; and a coloring layer on the switching element so as to cover at least a part of the switching element. Forming a through-hole in the colored layer; performing reverse sputtering with an energy of 8000 J or less on the colored layer in which the through-hole is formed; and coloring the formed through-hole. Forming a pixel electrode on a layer, arranging a counter substrate facing the array substrate at a predetermined interval, and enclosing liquid crystal between the array substrate and the counter substrate. A method for manufacturing a liquid crystal display device characterized by the above-mentioned. 2. The method according to claim 1, further comprising the step of irradiating the colored layer with ultraviolet rays before the step of performing the reverse sputtering. 3. The method according to claim 1, wherein the reverse sputtering is performed by Ar. 4. An active matrix substrate in which switching elements are formed in a matrix corresponding to intersections between signal lines and scanning lines; and a coloring layer formed so as to cover at least a part of the switching elements. A through-hole formed in the colored layer; a surface-modified layer formed by performing reverse sputtering with an energy of 8000 J or less on the colored layer in which the through-hole is formed; and a laminate on the colored layer. A pixel electrode electrically connected to the switching element via the through hole; a counter substrate disposed to face the active matrix substrate at a predetermined interval; and the active matrix substrate and the counter substrate. A spacer for holding the substrate at the predetermined interval; and a spacer provided between the active matrix substrate and the counter substrate. A liquid crystal display device, comprising a liquid crystal layer.