JP2002207208A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate various defects caused by the presence of a color filter in a liquid crystal display layer using an electrode plate, on which a transparent coloring layer (color filter) is formed, as an electrode plate on the side where switching elements such as thin film transistors(TFTs) and transparent electrodes for driving pixels are formed. SOLUTION: The device is characterized by using the electrode plate having the coloring pattern layer composed of a heat resistant acrylate resin or polyimide provided on a substrate and having the switching elements and the transparent electrodes for driving the pixels formed thereon via a transparent coating layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a color liquid crystal display device.

[0002]

2. Description of the Related Art Forming a transparent colored layer (color filter) on an electrode plate on which a switching element such as a thin film transistor (TFT) and a transparent electrode for driving a pixel are formed can be achieved by simplifying an opposing substrate or by using both. It is considered to be desirable from the viewpoint of preventing displacement and dimensional displacement when bonding the electrode plates, and attempts have been made to realize this configuration.
However, in the case of this configuration, various problems have occurred due to the presence of the color filters.

[0003] That is, these are listed as follows. 1. A configuration in which a color filter is arranged on a pixel electrode, that is, the layer configuration is, for example, as shown in FIG.
Transparent pixel electrode 31 Color filter 20 Alignment film 51
, The transparent pixel electrode 31
Since the color filter 20 is further added to the polyimide alignment film 51 between the and the counter electrode 32, the effect of increasing the electrical resistance is obtained, and a new voltage loss occurs. Usually, in this case, the overcoat layer 41 is provided on the color filter 20 layer in order to flatten the surface disorder due to the formation of the color filter layer, so that the voltage loss further increases, and it becomes necessary to increase the applied voltage. There is a problem that the driving response is deteriorated.

[0004] 2. Therefore, when the transparent pixel electrode 31 is provided on the color filter 20 to solve the above problem,
That is, as shown in FIG.
1 color filter 20 transparent pixel electrode 31 alignment film 51
, The transparent pixel electrode 31
And the switching element 30 is conducted through the through hole A. In this case, the color filter 20
Of the switching element 30 and the transparent pixel electrode 31
This makes it difficult to keep the contact resistance constant with the contact resistance, and in severe cases, it causes poor contact, that is, the generation of defective pixels.

[0005] 3. The surface of the color filter 20 is
Steps and non-uniformity are apt to occur, which may cause disorder in the alignment of the liquid crystal 61 and non-uniformity in the thickness (gap width) of the liquid crystal layer, resulting in uneven display images. In view of the above situation, the color filter 20 has been provided on the other electrode plate side facing the switching element 30 in most liquid crystal display devices.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display device using an electrode plate which can solve the above-mentioned various problems at once.

[0007]

According to the present invention, a colored pattern layer of a heat-resistant acrylate resin or polyimide is formed on a substrate, a transparent coating layer is interposed therebetween, and a switching element and a transparent electrode for driving pixels are formed thereon. A liquid crystal display device characterized by using an electrode plate formed with (1) and (2).

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to solve the various problems caused by the existence of the color filter, the present invention provides a switching element and a pixel drive through an insulating transparent coating layer on the color filter. A transparent electrode for use. In order to make these possible, the color filter is required to have heat resistance enough to withstand the temperature of the heat treatment in the subsequent step. Therefore, as a material of the color filter, a pigment having higher heat resistance than a dye is used as a coloring material. The medium in which the pigment is dispersed is a resin serving as a skeleton component of the color filter, and the resin is preferably a resin having heat resistance. Specifically, an acrylate resin or a polyimide resin having a heat-resistant temperature of 230 to 250 ° C. is exemplified.

[0009] The transparent coating film is provided for alleviating steps and fine irregularities on the surface of the color filter, and can be called a smoothing layer. By flattening the surface, the characteristics of the switching element formed thereon and the characteristics of the transparent electrode for driving a pixel are advantageously obtained. As the material of the transparent coating layer, in addition to the same heat-resistant resin used for the color filter, a transparent inorganic substance such as silicon dioxide (SiO2), tantalum pentoxide (Ta2O5), and silicon nitride (Si3N4) should be used. Can be. A transparent coating layer having a multilayer structure in which a transparent inorganic substance is laminated on a heat-resistant resin may be used.

Next, the switching element will be described. Thin film transistor (TF
When T) is provided, it basically includes a gate electrode, a gate insulating film, an amorphous silicon layer, a passivation layer, an ohmic layer, a source electrode, and a drain electrode.
Among them, the gate insulating film, the amorphous silicon layer, and the passivation layer are required to have a dense layer structure, and therefore it is necessary to raise the substrate temperature to some extent even when forming the film by the plasma CVD method. Was. However, the present invention adopts a process of forming a film at a low temperature equal to or lower than the heat resistance temperature of 230 to 250 ° C. of the color filter below the switching element. One of the specific means is to introduce hydrogen radicals (H *) during plasma CVD, whereby various film structures having desired physical properties can be obtained.

[0011]

<Example 1> TF of TFT type liquid crystal display device
An example of the manufacturing process of the T-forming side electrode plate will be described below with reference to FIG. An overcoat layer 41 made of an acrylic resin is formed on a pigment-dispersed color filter 20 having an acrylate resin as a resin component and having a plurality of color patterns formed on a glass substrate 11, and a chromium gate electrode 33 is formed thereon.
And transparent pixel electrode 3 of ITO (indium-tin oxide)
1 was patterned.

Next, a gate insulating film 34 was formed to a thickness of 0.5 μm by plasma CVD using SiNx. here,
The substrate temperature is 230 ° C., 170 sccm of hydrogen, 10% silane diluted with hydrogen (SiH4: 10%, H2: 90%)
Is supplied into the reaction chamber at a flow rate of 50 sccm, and ammonia diluted with hydrogen is also supplied at a flow rate of 34 sccm.
Film formation was performed at a load power of 180 W and a deposition rate of 1 ° / sec. At this time, in order to realize a low-temperature film formation of 230 ° C., hydrogen radicals (H *) (hydrogen 20 sccm) formed by microwaves (2.45 GHz, 400 W) are converted to S
Introduced during plasma CVD of iNx. This is because, as shown in FIG.
, And hydrogen is supplied from the middle of the waveguide 72 to generate hydrogen radicals.
It is mainly supplied to the substrate 11.

Subsequently, amorphous silicon (a-Si:
H) The layer 35 was formed to a thickness of 0.05 μm by plasma CVD. Here, the substrate temperature is 230 ° C., 10% silane diluted with hydrogen (SiH4: 10%, H2: 90%) is supplied into the reaction chamber at a flow rate of 300 sccm, and the pressure is 1 torr.
The film was formed at a load power of 60 W and a deposition rate of 1 ° / sec. Subsequently, the passivation layer 36 was similarly formed to a thickness of 0.5 μm by plasma CVD using SiNx.
Also in this case, hydrogen radicals (H *) (hydrogen 20 scc)
m) was introduced during SiNx plasma CVD. Thereafter, reactive ion etching using a photoresist as a pattern corrosion-resistant film is performed in CF4 gas to form the gate insulating film 3.
4. The amorphous silicon layer 35 and the passivation layer 36 have a desired pattern.

Here, since the interface of the portion where the gate electrode 33 of the TFT overlaps the source electrode 38 and the drain electrode 39 is important in characteristics, the gate insulating film 34 and the amorphous silicon (a-Si: H) layer It is preferable that the passivation layer 36 be formed continuously and the passivation layer 36 be formed continuously. After that, patterning is performed.

Subsequently, a photoresist is used as a pattern corrosion-resistant film, and reactive ion etching is similarly performed in the passivation layer 36 in CF 4 gas to form two rectangular through holes. It was formed to a thickness of 0.05 μm by CVD. Here, the substrate temperature is 230 ° C., hydrogen is 150 sccm, 10% silane diluted with hydrogen (SiH4: 10%, H2: 90%) is 300 sccm in flow rate, and hydrogen diluted 1000 ppm PH3.
Is supplied into the reaction chamber at a flow rate of 90 sccm, and the pressure is 1 torr.
The film was formed at a load power of 60 W and a deposition rate of 0.6 ° / sec. Next, the source electrode 38 and the drain electrode 39
Was formed with a metal aluminum film to a thickness of 0.8 μm by sputtering, and a pattern was formed by wet etching.

Thereafter, an alignment film of polyimide is applied to the entire surface, and a rubbing process is performed. The polyimide film is bonded to the counter electrode plate while being aligned, and liquid crystal is injected between the two electrode plates and sealed to form a liquid crystal display. The device. In the obtained liquid crystal display device, a high-quality screen was obtained without occurrence of defective pixels or color unevenness.

<Embodiment 2> T of a TFT type liquid crystal display device
Another example of the manufacturing process of the FT formation side electrode plate will be described below with reference to FIG. A polyimide resin overcoat layer 41 is formed on a pigment-dispersed color filter 20 containing polyimide as a resin component and having a plurality of color patterns formed on a glass substrate 11, and a chromium gate electrode 3 is formed thereon.
3 and an opposite electrode 32a of the IPS (In-Plane Switching) type were patterned.

Next, a gate insulating film 34 was formed with a thickness of 0.5 μm by plasma CVD using SiNx. here,
The substrate temperature is 250 ° C., hydrogen is 170 sccm, and 10% silane diluted with hydrogen (SiH4: 10%, H2: 90%)
Is supplied into the reaction chamber at a flow rate of 50 sccm, and ammonia diluted with hydrogen is also supplied at a flow rate of 34 sccm.
Film formation was performed at a load power of 180 W and a deposition rate of 1 ° / sec. At this time, in order to realize a film formation at a low temperature of 250 ° C., hydrogen radicals (H *) (hydrogen 20 sccm) formed by microwaves (2.45 GHz, 400 W) are converted to S
Introduced during plasma CVD of iNx. This is because, as shown in FIG.
, And hydrogen is supplied from the middle of the waveguide 72 to generate hydrogen radicals.
The irradiation is mainly performed toward the substrate 11.

Subsequently, amorphous silicon (a-Si:
H) The layer 35 was formed to a thickness of 0.05 μm by plasma CVD. Here, the substrate temperature is 250 ° C., 10% silane diluted with hydrogen (SiH4: 10%, H2: 90%) is supplied into the reaction chamber at a flow rate of 300 sccm, and the pressure is 1 torr.
The film was formed at a load power of 60 W and a deposition rate of 1 ° / sec. Subsequently, a passivation layer 36 was formed to a thickness of 0.5 μm by plasma CVD using SiNx in the same manner.
Also in this case, hydrogen radicals (H *) (hydrogen 20 scc)
m) was introduced during SiNx plasma CVD. Then, reactive ion etching using a photoresist as a pattern corrosion-resistant film was performed in CF4 gas to form the amorphous silicon layer 35 and the passivation layer 36 into desired patterns.

Here, since the interface of the portion where the gate electrode 33 of the TFT overlaps the source electrode 38 and the drain electrode 39 is important in characteristics, the gate insulating film 34 and the amorphous silicon (a-Si: H) layer It is preferable that the passivation layer 36 be formed continuously and the passivation layer 36 be formed continuously. After that, patterning is performed.

Subsequently, a photoresist is used as a pattern corrosion-resistant film, and reactive ion etching is similarly performed in the CF 4 gas to form two rectangular through holes in the passivation layer 36. It was formed to a thickness of 0.05 μm by CVD. Here, the substrate temperature is 250 ° C., hydrogen is 150 sccm, 10% silane diluted with hydrogen (SiH4: 10%, H2: 90%) is 300 sccm, and PH3 diluted with hydrogen is 1000 ppm.
Is supplied into the reaction chamber at a flow rate of 90 sccm, and the pressure is 1 torr.
The film was formed at a load power of 60 W and a deposition rate of 0.6 ° / sec. Thereafter, the ohmic layer 37 was patterned by reactive ion etching using CF4 gas. Next, the source electrode 38 and the drain electrode 39 were formed by sputtering with a metal aluminum film to a thickness of 0.8 μm,
A pattern was formed by wet etching.

Thereafter, the opposing substrate was bonded, and liquid crystal was injected between the two substrates and sealed to obtain a liquid crystal display device. In the obtained liquid crystal display device, a defective pixel, color unevenness, and the like did not occur, and a high-quality screen having a wide viewing angle characteristic of the IPS system was obtained.

[0023]

According to the structure of the present invention, the above-mentioned various problems in the conventional structure, such as the voltage loss, the occurrence of defective pixels, and the display unevenness due to the disorder of the alignment of the liquid crystal, do not occur.
In addition, the number of steps conventionally required for improving the shape and accuracy and the number of steps for maintaining and managing the accuracy are reduced, and the process is simplified, so that the manufacturing becomes relatively easy.

[0024]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an electrode plate for a liquid crystal display device of the present invention.

FIG. 2 is a cross-sectional view illustrating a conventional electrode plate for a liquid crystal display device in which a color filter is provided on a transparent pixel electrode.

FIG. 3 is a cross-sectional view showing a conventional electrode plate for a liquid crystal display device in which a transparent pixel electrode is provided on a color filter.

FIG. 4 is a sectional view showing another embodiment of the electrode plate for a liquid crystal display device of the present invention.

FIG. 5 is an explanatory diagram showing a hydrogen radical supply unit used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Glass substrate 12 Counter substrate 20 Color filter 30 Switching element 31 Transparent pixel electrode 32 Counter electrode 33 Gate electrode 34 Gate insulating film 35 Amorphous silicon layer 36 Passivation layer 37 Ohmic layer 38 Source electrode 39 Drain electrode 41 Overcoat layer 42 Transparent insulating layer 51 Alignment film 61 Liquid crystal 71 Oscillator 72 Waveguide 73 CVD chamber

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09F 9/30 348 G09F 9/30 348A 5F110 349 349B 9/35 9/35 H01L 29/786 H01L 29/78 626C F-term (Reference) 2H048 BA45 BA48 BB02 BB37 BB44 2H090 HB02 HB03X HB07X HD13 2H091 FA02Y FB02 FB06 FD04 GA03 GA13 GA16 LA12 LA15 2H092 JA24 JB57 JB58 MA07 MA17 NA11 NA27 NA29 PA03 A04 BA03 A03 BA03 A04 ED03 5F110 AA16 AA18 BB01 CC07 DD02 DD12 EE04 FF03 FF30 GG02 GG25 GG45 HK03 HK09 HK33 HK35 NN02 NN12 NN24 NN27 NN35 NN72 QQ09

Claims (2)

[Claims] 1. An electrode plate having a heat-resistant acrylate resin or polyimide colored pattern layer provided on a substrate, and a switching element and a transparent electrode for driving pixels formed thereon with a transparent coating layer interposed therebetween. A liquid crystal display device characterized by the above-mentioned. 2. The method according to claim 1, wherein the transparent coating layer is a single layer or a multiple layer made of at least one selected from the same heat-resistant resin as the resin used for the color filter, silicon dioxide, tantalum pentoxide, or silicon nitride. 2. The liquid crystal display device according to claim 1, wherein: