JP2002277899A - Active matrix liquid crystal display and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an active matrix liquid crystal display, which protects a color filter and a black matrix without reducing the transmittance, and easily and precisely prescribe the gap between a TFT substrate and a counter substrate, without providing a spacer and its manufacturing method. SOLUTION: In a liquid crystal display device, having a CF(color filter) on TFT structure where a color filter 10, a black matrix(BM) 11 in the upper layer of a TFT and the upper layer of a data line 7, and a pixel electrode are provided on the TFT substrate having a gate line 5 and the data line 7, a first thick overcoat layer and a second thin overcoat layer are arranged on the BM 11, and only the second thin overcoat layer is arranged on the CF 10 in a display area, and the BM 11 is surely protected by the first overcoat layer, with attenuation of incident light being suppressed by the second overcoat layer to improve the effective numerical aperture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an active matrix type liquid crystal display device and a method of manufacturing the same, and more particularly, to a T-type liquid crystal display device.
Switching element such as FT (thin film transistor) and C
The present invention relates to an active matrix liquid crystal display device having a CF-on-TFT structure in which F (color filter) is formed on the same substrate, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, an active matrix type liquid crystal display device using a thin film transistor or the like as a switching element has been developed. This liquid crystal display device has a TFT on which a switching element such as a thin film transistor is formed.
The TFT substrate is formed of a gate electrode, a gate insulating film, a semiconductor layer, a thin film transistor including source / drain electrodes, and is formed for each pixel. Pixel electrode, a passivation film covering them, an alignment film, terminals for connection to an external circuit, and the like. The opposing substrate performs a black matrix that blocks light incident on the thin film transistor region and the wiring layer, and performs color display. It has a color filter of each color of RGB, a transparent electrode such as ITO, an alignment film, and the like, and a spacer for keeping a gap at a predetermined distance is sandwiched between both substrates.

In such an active matrix type liquid crystal display device, high definition is required in order to improve display quality. For this purpose, it is necessary to achieve high pixel density. In a liquid crystal display device having a structure in which a color filter and a black matrix are arranged on the counter substrate side, an error occurs in the alignment between the two substrates in an assembly process. Therefore, it is necessary to form the color filter and the black matrix in advance with a margin. Therefore, it is difficult to ensure the maximum area (opening ratio) of the pixel opening, which hinders high density.

Therefore, in order to reduce the margin of the color filter and the black matrix and improve the aperture ratio,
A method of forming a color filter and a black matrix on a TFT substrate side on which a switching element such as a thin film transistor is formed, that is, a so-called CF-on TFT, has been proposed in JP-A-2-54217 and JP-A-3-237.
No. 432 and the like describe the structure.

In the CF-on-TFT structure, since a color filter and a black matrix are formed on the TFT substrate side, there is no need to consider the alignment margin between the TFT substrate and the opposing substrate, so that the manufacturing process can be simplified and
Although it is possible to achieve an increase in the pixel aperture ratio, on the other hand, since the pixel electrode is formed on the color filter, a step is generated in the pixel electrode by reflecting the unevenness of the color filter and the like, and the step causes the alignment of the liquid crystal. Disturbance occurs, causing a problem of causing disclination, reverse tilt domain, and the like.

To solve this problem, Japanese Patent Application Laid-Open No. 8-122824
In Japanese Patent Laid-Open Publication No. H11-115, a method of forming a flattening film after patterning the color filter and the black matrix in order to fill the unevenness of the color filter and the black matrix is disclosed. A liquid crystal display device having a flattening film described in the above publication will be described with reference to FIG. Japanese Patent Application Laid-Open No. 8-122824 discloses a technique using a polycrystalline silicon TFT (p-SiTFT) as a switching element. However, for the sake of explanation, a channel-etch type amorphous silicon TFT (a) is used as the switching element here. -SiTFT) will be described.

As shown in FIG. 17, in the liquid crystal display device described in the above publication, a gate electrode 5b is formed on a transparent insulating substrate 4, and a gate insulating film 6 is formed so as to cover the gate electrode 5b.
Are formed. A semiconductor layer 15 is formed thereon so as to overlap with the gate electrode 5b, and a source electrode 8b and a drain electrode 8a separated on the center of the semiconductor layer 15 via an ohmic contact layer (not shown). And a thin film transistor is formed. And
A passivation film 9 is formed to cover the thin film transistor.

Here, in the liquid crystal display device having a CF-on-TFT structure, a color filter 10 and a black matrix 11 are formed on the passivation film 9, and a pixel electrode 14 is formed thereon via an overcoat layer. However, the above publication is characterized in that a thick flattening film 24 is provided in order to flatten a step between the color filter 10 and the black matrix 11, and the color filter 10 and the black matrix 11 are completely embedded. Then, the flattening film 24 and the passivation film 9
After forming a contact hole 19 penetrating through the pixel electrode 1
A transparent conductive film 4 is formed and connected to the source electrode 8b.

In the process of forming the CF on TFT substrate, Optica is used as a light shielding film of the thin film transistor.
l Density (OD) = approximately 3 (when the amount of light incident on the BM is T0 and the amount of light emitted is T1, OD = −
It is necessary to form a fine pattern of the photosensitive resin black matrix layer of log 10 (defined as T1 / T0). Japanese Patent Application No. 2000-013571 discloses that a photosensitive resin black matrix is formed on the underlying color filter 10. And a technique for forming a fine pattern by exposing to light. According to this method, even if only the surface of the high-OD black matrix 11 is exposed, the underlying color filter 10 and the black matrix 11 are exposed.
Because of its good adhesion, a fine pattern can be formed without peeling off from the base color filter 10.

[0010]

In the above-mentioned flattening technique,
A flattening film 24 is formed to cover a step formed on the TFT substrate.
Is generally applied, the thickness of the black matrix 11 and the color filter 10 is about 1 to 2 μm, and when they are superimposed, a step of about 2 to 3 μm is generated. Therefore, when the step is to be covered with the flattening film 24, the thickness is required to be about 1.5 times the step, and the flattening film 24 is required to have a thickness of about 3 to 4.5 μm. The film thickness of the flattening film 24 on the filter 10 becomes large.

Here, when a photosensitive acrylic resin, particularly a positive photosensitive acrylic resin, is used as the flattening film 24, the transmittance of light near a wavelength of 400 to 500 nm is 95% per 1 μm of film thickness. And the amount of transmitted light is about 85% for the entire flattening film 24 having a thickness of 3 μm.
Problems such as deterioration of the transmittance of the liquid crystal display device and collapse of the white balance occur. As described above, since the effective transmittance is reduced by the thick planarizing film 24,
Without completely flattening the steps of the color filter 10 and the black matrix 11, the disclination caused by the steps should be shielded by the black matrix.
On the contrary, there is a case where the transmittance is effectively increased.

On the other hand, when the flattening film 24 is not provided at all, it can be seen that the color filter 10 and the black matrix 11 swell due to a stripping solution used in the subsequent patterning step and peel off from the end. Was. When the same material as the flattening film 24 such as acrylic is formed in a thin film on the color filter 10 and the black matrix 11 and used only as an overcoat layer, the overcoat layer is generally applied by spin coating. Since the steps of the filter 10 and the black matrix 11 are too large, they can hardly be applied to the surface of the portion where the steps of the color filter 10 and the black matrix 11 are large. It was found that problems such as the black matrix swelling in the resist stripping step and peeling of the film occurred.

As described above, when the CF-on TFT structure is used, the aperture ratio can be improved by reducing the alignment margin between the TFT substrate and the counter substrate, but a large step is generated by the color filter 10 and the black matrix 11. If the thick flattening film 24 is formed to fill the step, the light absorption by the flattening film 24 lowers the transmittance, and the effect of improving the aperture ratio is canceled out. There is.

The present invention has been made in view of the above problems, and a main object of the present invention is to provide a CF-on-TFT structure capable of reliably protecting a color filter and a black matrix without reducing transmittance. And a method of manufacturing the same.

Another object of the present invention is to provide an active matrix type liquid crystal display device capable of easily and precisely defining a gap between a TFT substrate and a counter substrate without separately providing a spacer, and a method of manufacturing the same. Is to do.

[0016]

In order to achieve the above object, the present invention provides a liquid crystal display device in which a liquid crystal is sandwiched between a pair of substrates disposed opposite to each other, and a plurality of gate lines and data lines intersecting each other are provided on one substrate. A line, a thin film transistor provided in the vicinity of the intersection of the gate line and the data line, a color filter provided in each pixel region surrounded by the gate line and the data line, and the thin film transistor and the color filter. An active matrix type liquid crystal display device having an overcoat layer that covers the surface of the one side substrate, wherein the overcoat layer has a thickness on the color filter larger than a thickness on a region excluding the color filter. Is also formed to be thin. The active matrix type liquid crystal display device having the basic configuration of the present invention has the following suitable application forms.

First, the overcoat layer has a structure in which a plurality of overcoat layers are laminated on a region excluding the color filter.

Second, a liquid crystal is interposed between a pair of substrates disposed opposite to each other, and a plurality of gate lines and data lines intersecting with each other, and the gate lines and the data lines are provided on one substrate. A thin film transistor provided in the vicinity of the intersection area of the pixel, a color filter provided in each pixel surrounded by the gate line and the data line, and an overcoat covering the surface of the one side substrate including the thin film transistor and the color filter. An active matrix type liquid crystal display device, comprising: a first overcoat layer and a second overcoat layer, wherein the second overcoat layer is formed on the color filter. Only one is provided.

Third, a liquid crystal is sandwiched between a pair of substrates disposed opposite to each other, and a plurality of gate lines and data lines crossing each other, and the gate lines and the data lines are provided on one substrate. , A color filter provided in each pixel region surrounded by the gate line and the data line, and an overcoat covering the one-side substrate surface including the thin film transistor and the color filter. An active matrix type liquid crystal display device having a coat layer, wherein the overcoat layer comprises a first overcoat layer and a second overcoat layer, and the second overcoat layer is provided on the color filter. Only layers are provided.

Fourth, a liquid crystal is sandwiched between a pair of substrates disposed opposite to each other, and a plurality of gate lines and data lines crossing each other, and the gate lines and the data lines are provided on one substrate. , A color filter provided in each pixel region surrounded by the gate line and the data line, and an overcoat covering the one-side substrate surface including the thin film transistor and the color filter. An active matrix type liquid crystal display device having a coat layer, wherein the overcoat layer comprises:
A color filter having a first overcoat layer and a second overcoat layer, wherein the color filter is formed between the first overcoat layers;
An active matrix liquid crystal display device, wherein the active matrix type liquid crystal display device is formed so as to cover the surface of the one side substrate including the color filter and the first overcoat layer.

Fifthly, a spacer is formed on the projection formed including the thin film transistor and the overcoat layer, and a gap between the opposing substrates is defined by the projection and the spacer. Alternatively, the thickness of the overcoat layer is set so that the convex portion formed including the thin film transistor and the overcoat layer abuts on the opposing substrate, and the thickness of the overcoat layer is set between the opposing substrates by the convex portion. A gap is defined.

Sixth, a black matrix is formed on the thin film transistor region, and the color filter is formed on the thin film transistor region.

Next, seventh, a black matrix is formed on the data line.

Next, a method of manufacturing an active matrix type liquid crystal display device according to the present invention includes a plurality of gate lines and data lines intersecting with each other on a first substrate, and each pixel surrounded by the gate lines and the data lines. Forming a thin film transistor in a region, arranging a color filter in each pixel region surrounded by the gate line and the data line via a passivation film, and the one-side substrate surface including the color filter Forming an overcoat layer so as to cover the first substrate, forming a pixel electrode on the overcoat layer, and disposing a second substrate on the first substrate to face the first and second substrates. And a step of interposing a liquid crystal between the active matrix liquid crystal display device and the color filter when forming the overcoat layer. It has a basic configuration in which the overcoat layer on the filter is formed thinner than the overcoat layer in other regions. The manufacturing method of the active matrix type liquid crystal display device having the basic configuration of the present invention has the following suitable application forms.

First, the overcoat layer comprises:
A plurality of overcoat layers are formed by spin coating, and an overcoat layer having a lower viscosity than an overcoat layer in another region is used for the overcoat layer on the color filter, or the overcoat layer includes a plurality of overcoat layers. The overcoat layer is formed by spin-coating, and the overcoat layer on the color filter is formed by spin coating having a higher rotation speed than the overcoat layers in other regions.

Second, a step of forming a thin film transistor in each pixel region surrounded by the gate line and the data line, together with a plurality of gate lines and data lines intersecting with each other on the first substrate; Providing a color filter in each pixel region surrounded by the gate line and the data line via a film, and forming an overcoat layer so as to cover the surface of the first substrate including the color filter A step of forming a pixel electrode on the overcoat layer, a step of disposing a second substrate to face the first substrate, and holding a liquid crystal between the first and second substrates; Wherein the step of forming the overcoat layer includes forming a first overcoat layer and a second overcoat layer sequentially. The color filter is formed so as to cover the color filter with the second overcoat layer.

Third, a step of forming a thin film transistor in each pixel region surrounded by the gate line and the data line, together with a plurality of gate lines and data lines crossing each other on the first substrate; Providing a color filter in each pixel region surrounded by the gate line and the data line via a film, and forming an overcoat layer so as to cover the surface of the first substrate including the color filter A step of forming a pixel electrode on the overcoat layer, a step of disposing a second substrate to face the first substrate, and holding a liquid crystal between the first and second substrates; A method of manufacturing an active matrix liquid crystal display device, wherein the step of forming the overcoat layer comprises a step of forming a first overcoat on the surface of the first substrate excluding the color filter. A first overcoat layer, which is thinner than the first overcoat layer, on the color filter.
The overcoat layer and the second overcoat layer,
It is performed in one step by making the exposure amount of each overcoat layer portion different, and the adjustment of the exposure amount is performed in one step using a gray-tone mask composed of a light-shielding portion, a semi-transmission portion, and a transmission portion. Do.

Fourth, forming a thin film transistor in each pixel region surrounded by the gate line and the data line, together with a plurality of gate lines and data lines intersecting with each other on the first substrate; Providing a color filter in each pixel region surrounded by the gate line and the data line via a film, and forming an overcoat layer so as to cover the surface of the first substrate including the color filter A step of forming a pixel electrode on the overcoat layer, a step of disposing a second substrate to face the first substrate, and holding a liquid crystal between the first and second substrates; Wherein the step of forming the overcoat layer comprises the steps of: forming a first overcoat layer and forming a second overcoat layer.
Forming an overcoat layer of the first
Forming the overcoat layer is between the step of forming the thin film transistor and the step of forming the color filter, wherein the first overcoat layer is formed on the surface of the first substrate excluding the region where the color filter is formed. The step of forming a color filter is performed by forming a color filter between the first overcoat layers, and the step of forming the second overcoat layer is performed by forming a color filter between the first overcoat layers. Between the step of forming the color filter and the step of forming the pixel electrode, covering the surface of the first substrate including the color filter and the first overcoat layer with a second overcoat layer. This is done by:

Fifth, after forming a convex portion including the thin film transistor and the overcoat layer, a spacer is formed on the convex portion to define a gap between the first and second substrates. Alternatively, when forming a convex portion including the thin film transistor and the overcoat layer, the convex portion abuts on the second substrate to define a gap between the first and second substrates, The thickness of the overcoat layer is adjusted.

Next, sixth, a black matrix is formed on the thin film transistor region, and the color filter is formed on the thin film transistor region.

Next, seventh, a black matrix is formed on the data lines.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a preferred embodiment of the active matrix type liquid crystal display device according to the present invention, a TFT in which a gate line, a data line and a TFT are formed is provided.
A liquid crystal display device having a CF-on-TFT structure in which a color filter, a black matrix formed in a TFT upper layer and a data line upper layer, and a pixel electrode are provided on a substrate,
A thick first overcoat layer and a thin second overcoat layer are disposed on the black matrix, and only the thin second overcoat layer is disposed on the color filter in the display area. The black matrix is reliably protected by the thick first overcoat layer, and the attenuation of incident light is suppressed by the thin second overcoat layer, so that the effective aperture ratio can be improved. .

[0033]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention;

Embodiment 1 First, an active matrix type liquid crystal display device according to a first embodiment of the present invention and a method for manufacturing the same will be described with reference to FIGS.
FIG. 1 is a circuit diagram showing a configuration of a liquid crystal display device, and FIG.
FIG. 3 is a plan view schematically showing a positional relationship between a color filter, a black matrix, and an overcoat layer which is a feature of the present embodiment. FIG. 4 is a cross-sectional view showing the structure of the liquid crystal display device of the present embodiment, and FIG. 5 is a process cross-sectional view showing a manufacturing method thereof.

As shown in FIG. 1, the active matrix type liquid crystal display device has a gate line 5 on a transparent insulating substrate.
The data lines 7 are arranged so as to be orthogonal to each other, and the TFT 17 is formed so as to correspond to the intersection of these wirings. The gate line 5 is connected to the gate electrode of the TFT 17,
The TFT 17 corresponding to the pixel is driven by a scanning signal input from the gate line 5 to the gate electrode. The data line 7 is connected to the drain electrode of the TFT 17, and inputs a data signal to the drain electrode. A pixel electrode is connected to the source electrode of the TFT 17, and the liquid crystal layer 3 between the pixel electrode and the counter electrode formed on the counter substrate provides a pixel capacitance 18.
Is formed.

Next, referring to FIGS. 2 and 3, the color filter 10, the black matrix 11, the first and second overcoat layers 1 in the liquid crystal display device of the present embodiment.
The positional relationship with 2 and 13 will be described. FIGS. 2 and 3 show the structure of the pixel portion. When the respective layers are shown in the same drawing, the overlapping relationship becomes unclear. FIG. 2 shows the gate line 5, the data line 7, and the black matrix. 1
1, the positional relationship between the first and second overcoat layers 12 and 13 is described, and FIG. 3 illustrates the positional relationship between the gate line 5, the data line 7, the color filter 10, and the black matrix 11.

As shown in FIG. 2 and FIG.
A black matrix 11 is formed on the data line 7,
The light shielding of the TFT 17 and the light leakage around the wiring are performed. Then, a first overcoat layer 12 is provided so as to cover these black matrices 11,
The black matrix 11 is protected. Further, a second overcoat layer 13 is provided so as to cover the black matrix 11, the color filter 10, and the first overcoat layer 12. The pixel electrode is connected to the source electrode 8b via the contact hole 19 of the second overcoat layer 13.

Here, the first and second overcoat layers 12 and 13 provided in the present embodiment are not intended for flattening, but rather are thick on the black matrix 11 serving as the convex portion of the TFT substrate. The black matrix 11 and the color filter 10 are thinly formed on the color filter 10.
Is not flattened by the overcoat layers 12 and 13, it is necessary to hide the disclination caused by the disorder in the alignment of the liquid crystal. The overlap width between the black matrix 11 and the pixel electrode is 2 to 5 μm.
It is preferable to secure the degree.

Next, the structure of the active matrix type liquid crystal display device of this embodiment will be described with reference to FIG. As shown in FIG. 4, in the TFT substrate 1 of the present embodiment, a gate electrode 5b is provided on a transparent insulating substrate 4, and a gate insulating film 6 is formed so as to cover them. A semiconductor layer 15 is provided thereon so as to overlap with the gate electrode 5b, and a source electrode 8b and a drain electrode 8a separated on the center of the semiconductor layer 15 are connected to each other via an ohmic contact layer (not shown). Connected to layer 15.
Further, the ohmic contact layer between the source electrode 8b and the drain electrode 8a is removed by etching to provide a channel portion, and the TFT 17 is formed. Then, a passivation film 9 is formed so as to cover the TFT 17, color filters 10 of RGB are provided in a display region and a TFT region of each pixel, and a color filter 10 of the TFT region and an upper layer of the semiconductor layer 15 in the TFT region. On the upper layer, a black matrix 11 for shielding light is formed.

Then, on the black matrix 11,
Thick first overcoat layer 1 for covering it
2 are provided along the outer shape of the black matrix 11. The first overcoat layer 12 is formed in a portion that cannot be covered by the second overcoat layer 13, and has a thickness capable of covering the black matrix 11, for example, about 1 μm to 3 μm. However, as shown in the second embodiment, when the gap between the substrates is adjusted by the first overcoat layer 12, the thickness may be further increased.

Then, a thin second overcoat layer 13 is formed so as to cover the first overcoat layer 12 provided on the color filter 10 and the black matrix 11.
Is provided, and the color filter 10 is protected. The thickness of the second overcoat layer 13 is
In order to suppress a decrease in the transmittance of 0, it is better to be thin.
Preferably it is 5 μm.

When the TFT 17 is used as a switching element, the source electrode 8b functions as an extraction electrode for connection with the pixel electrode 14, and is provided through the second overcoat layer 13 and the passivation film 9. The source electrode 8 b and the pixel electrode 14 are connected through the contact hole 19. In addition, on the passivation film 9, color filters 10 of R, G, and B color layers are provided at portions corresponding to the pixel display areas. The color filters 10 are formed around the contact holes 19. Absent.

In FIG. 4, the color filter 10 is also formed in the TFT forming region, but this is for improving the adhesion of the black matrix, and the color filter 10 is formed with the passivation film by other means such as HMDS processing. When the adhesion of the black matrix is increased, the color filter 10 under the black matrix may or may not be provided. Also, in FIG.
The black matrix 11 is also formed on the data line 7, and the black matrix 11 prevents light from entering a region in which the alignment direction is disturbed due to the influence of the potential of the data line 7, thereby improving display quality. However, the black matrix 11 on the data line 7 need not always be provided.

Next, referring to FIG.
A method of manufacturing the device will be described. First, as shown in FIG. 5A, a channel-etch type TFT is formed on a transparent insulating substrate 4.
To form Specifically, on a transparent insulating substrate 4 made of glass or the like, aluminum (Al), molybdenum (M
o), a film made of a metal such as chromium (Cr) is formed in a thickness of about 100 to 400 nm by a sputtering method or the like, and a desired gate electrode 5b is formed by a known photolithography method.
And the gate lines 5 are patterned.

Next, on the gate electrode 5b and the transparent insulating substrate 4, a silicon oxide film, a silicon nitride film, and an insulating film such as a laminated film of the gate insulating film 6 are formed into a film having a thickness of about 100 to 200 nm by a CVD method or the like. The film is formed to be thick. Next, an amorphous silicon film having a thickness of about 400 nm is formed by a CVD method or the like, and is patterned into a desired shape.
To form Then, the source electrode 8b and the drain electrode 8
A material made of a metal such as Al, Mo, Cr, or the like a is formed into a film having a thickness of about 100 to 400 nm by a sputtering method or the like, and is patterned into a desired electrode shape by a photolithography method. Unnecessary ohmic contact layer between 8a is removed and T
The channel part of FT17 is formed.

Further, a passivation film 9 such as a silicon nitride film is deposited to a thickness of about 100 to 200 nm so as to cover them, and is patterned to form a contact hole 19 for connecting the pixel electrode 14 and the source electrode 8b.
To form The passivation film 9 may be made of an inorganic material such as a silicon nitride film or a transparent resin material such as an epoxy resin or an acrylic resin.

Next, as shown in FIG. 5B, a color filter 10 and a black matrix 11 are provided on the TFT substrate 1.
To form First, a negative photocurable color resist in which a red pigment is dispersed in an acrylic resin is applied on a substrate by spin coating. At that time, the spin rotation speed is adjusted so that the film thickness becomes about 1.6 μm. Next, pre-baking is performed at 80 ° C. for 2 minutes on a hot plate, and after exposure, developed with a 0.04% solution of TMAH (tetramethylammonium hydroxide), baked at 230 ° C. for 1 hour, and the corresponding portion is colored red. The color filter 10 is formed. Similarly, green and blue color filters 10 and a black matrix 11 are formed.

Next, as shown in FIG. 5C, a black matrix 11 provided on each color filter 10 is formed.
Of the thick overcoat layer 12 for protecting the surface of the first overcoat layer 12 is formed. The first overcoat layer 12 is formed by, for example, spin-coating an acrylic positive photosensitive resin having a viscosity of about 15 cp at a rotation speed of 800 rpm / 10 s. Then, after developing with a 0.4% TMAH solution, baking is performed at 220 ° C. for 1 hour. As a result, the first overcoat layer 12 having a thickness of about 1 μm is formed on the black matrix 11.

Subsequently, as shown in FIG. 5D, a second overcoat layer 13 of a thin film for protecting the color filter 10 is formed. The second overcoat layer 13 is formed, for example, by spin-coating an acrylic positive photosensitive resin having a viscosity of about 5 cp at a rotation speed of about 1000 rpm / 10 s, and then developing with a 0.4% TMAH solution. It is done by doing. At this time, a contact hole 19 for connecting the pixel electrode 14 and the source electrode 8b is formed.
To form Thereafter, in order to further make the positive photosensitive resin transparent, photocrosslinking is performed by exposing the entire surface to UV light mixed with ghi rays at an illuminance of about 4 to 8 J, thereby making the second overcoat layer 13 transparent. . After that, firing is performed at 220 ° C. for about 1 hour. Thereby, the film thickness of the second overcoat layer 13 on the color filter 10 is 0.5 μm to 1.0 μm.
It is about 5 μm.

In the present embodiment, when forming the first and second overcoat layers 12 and 13, positive photosensitive resins having different viscosities are used, and the film thickness is further changed by changing the number of revolutions of spin coating. However, a photosensitive resin having the same viscosity can be used, and the film thickness can be changed by changing only the rotation speed of spin coating. Further, after forming the first overcoat layer 12 of the thick film, the second overcoat layer 13 of the thin film is formed, but the order is reversed, and the overcoat layer of the thin film is formed first. Thereafter, a thick overcoat layer may be formed. Further, the contact hole of the second overcoat layer 13 was formed after the contact hole of the passivation film 9 was formed, but the order was reversed, and the passivation was performed after the contact hole of the second overcoat layer 13 was formed. It is also possible to pattern the contact holes in the film 9.

Then, as shown in FIG. 5E, a pixel electrode 14 is formed by forming a transparent conductive film such as ITO by sputtering or the like and patterning it. At this time, better coverage can be obtained as the film thickness of the pixel electrode 14 is larger.
About 100 nm is appropriate. After that, according to a normal method, an alignment film is formed on the TFT substrate 1 and the counter substrate 2 on which the counter electrode 16 such as ITO is arranged. Is formed.

As described above, in the liquid crystal display device of the CF-on-TFT structure in which the color filter 10 and the black matrix 11 are formed on the TFT substrate 1, the step of the substrate due to the color filter 10 and the black matrix 11 is large. In the example, a thick overcoat layer 12 having a large viscosity is provided on the black matrix 11,
By forming the second overcoat layer 13 of a thin film having a low viscosity on the color filter 10, the surface of the black matrix 11 is sufficiently covered and protected, and the transmittance of light incident on the color filter 10 is reduced. Can be suppressed.

Specifically, in the liquid crystal display device formed by the method of the present embodiment, the transmittance of the substrate is about 97% in the wavelength region of 400 to 450 nm, and the flattening film 2 as in the prior art is obtained.
4 was able to significantly reduce the decrease in transmittance as compared with the structure where 4 was provided. In the present embodiment, the first overcoat layer 12 on the black matrix 11 is formed thick at the expense of flatness, and disclination caused by the unevenness of the pixel electrode 14 formed thereon. In the case where the overlap width of the black matrix 11 and the pixel electrode 14 is completely flattened (W = 1.5
(approximately .mu.m), the aperture ratio is small because it is 2 to 5 .mu.m, but the transmissivity is further improved, so that the effective panel transmissivity is a flattened liquid crystal display device. Is bigger than.

In the structure of this embodiment, since the thick first overcoat layer 12 is also formed on the data line 7, the distance between the data line 7 and the pixel electrode 14 can be increased. As a result, the coupling capacitance between the data line 7 and the pixel electrode 14 can be reduced, and the display quality can be improved.

In the embodiment described above, the first and second
Of the overcoat layers 12 and 13 are formed by spin coating using an acrylic positive photosensitive resin.
The materials 2 and 13 are not limited to the above materials. The first overcoat layer 12 is a material whose viscosity can be easily adjusted and a pattern can be formed, and the second overcoat layer 13 has a higher transmittance. Any material may be used as long as it is a high material, and both may be formed using different materials. Further, the forming method is not limited to the coating method. For example, an insulating film or the like may be formed by a sputtering method, a CVD method, or the like.

The present invention can be applied to any liquid crystal display device in which the connection between the pixel electrode and the switching element is made through the color filter 10 or the black matrix 11. There is no particular limitation, and not limited to TFTs, MIMs, diodes, etc. may be used.
The forward stagger type a-Si TFT 17 or the planar type p-Si TFT 17 may be used.

In the liquid crystal display device of the present invention, there is no particular limitation on the configuration other than the above. For example, a liquid crystal material, an alignment film, a counter substrate, a counter electrode and the like are generally used in an active matrix type liquid crystal display device. May be configured. Each color filter is generally composed of three colors of red (R), green (G), and blue (B) for full-color display, but can be changed as appropriate.

Embodiment 2 Next, an active matrix type liquid crystal display device according to a second embodiment of the present invention and a method for manufacturing the same will be described with reference to FIG. FIG.
FIG. 2 is a cross-sectional view illustrating a structure of the liquid crystal display device according to the embodiment. The present embodiment is characterized in that the black matrix on the data line is embedded in the color filter to reduce the steps on the data line, and the first overcoat layer on the data line is omitted. The structure and manufacturing method are the same as in the first embodiment.

As shown in FIG. 6, in the TFT substrate 1 of the present embodiment, a gate electrode 5b and a gate insulating film 6 are formed on a transparent insulating substrate 4 and a semiconductor is formed thereon so as to overlap with the gate electrode 5b. A layer 15 is provided, and a source electrode 8 b and a drain electrode 8 a are connected to the semiconductor layer 15 via an ohmic contact layer to form a TFT 17.
Then, a passivation film 9 is provided so as to cover the TFT 17.

Then, on the passivation film 9, R,
A color filter 10 for each of the G and B color layers is provided in a portion corresponding to the pixel display area, and a black matrix 11 for shielding light is provided thereon. Here, in the first embodiment described above, the black matrix 11 is provided on the color filter 10 in order to improve the adhesion, but in the present embodiment, a gap is provided between the adjacent color filters 10 and the gap is provided. , A black matrix 11 is embedded.

Then, a thick first overcoat layer 12 for covering the black matrix 11 is provided. In this embodiment, the black matrix 11 on the data line 7 is embedded in the color filter 10. Therefore, the step is reduced, and it is not necessary to provide the first overcoat layer 12 in this portion. The first filter provided on the color filter 10 and the black matrix 11
A second overcoat layer 13 of a thin film is provided so as to cover the overcoat layer 12 of FIG.

As described above, in the liquid crystal display device of this embodiment, since the large step (0.5 to 1 μm) is formed on the TFT 17, the black matrix 11 formed on the color filter 10 is protected. Although the first overcoat layer 12 is required for performing the above, the first overcoat layer 12 can be omitted because the step on the data line 7 is as small as 0.1 to 0.2 μm.

By eliminating the first overcoat layer 12 on the data line 7, the step near the data line 7 is reduced, so that the pixel electrodes 14 can be prevented from rising and disclination can be suppressed. it can.
Thus, the overlap width between the black matrix 11 and the pixel electrode 14 can be reduced, and the aperture ratio can be increased as compared with the first embodiment.
The black matrix 1 at the end of the color filter 10
Since the step due to 1 is small, liquid pool is unlikely to occur when the second overcoat layer 13 is formed, and the second overcoat layer 13 on the color filter 10 is thinned.
And it can be formed uniformly.

Third Embodiment Next, an active matrix liquid crystal display device according to a third embodiment of the present invention and a method for manufacturing the same will be described with reference to FIG. FIG.
FIG. 2 is a cross-sectional view illustrating a structure of the liquid crystal display device according to the embodiment. In this embodiment, the black matrix on the data line is arranged between the color filters as in the second embodiment, but the color filters are formed after the first overcoat layer, and The shape is defined by the opening of the first overcoat layer, and the second overcoat layer is formed thereon. Therefore, the structure and manufacturing method other than the black matrix, the color filter, the first overcoat layer, and the second overcoat layer are the same as those in the first embodiment.

As shown in FIG. 7, in the TFT substrate 1 of the present embodiment, a gate electrode 5b and a gate insulating film 6 are formed on a transparent insulating substrate 4, and a semiconductor is formed so as to overlap with the gate electrode 5b. A layer 15 is provided, and a source electrode 8 b and a drain electrode 8 a are connected to the semiconductor layer 15 via an ohmic contact layer to form a TFT 17.
Then, a passivation film 9 is provided so as to cover the TFT 17. The black matrix 11 is provided on the semiconductor layer 15, and the first black matrix 11 is further provided thereon.
Of the overcoat layer 12 is formed. Further, a second overcoat layer 13 and a color filter 10 are formed below the pixel electrode 14 via the contact hole 19. Then, according to the present embodiment, the color filter 1
0 is formed inside the previously formed first overcoat layer 12. In this embodiment, a photosensitive acrylic resin is used for the first and second overcoat layers.

In this configuration, the total thickness of the overcoat layer on the drain electrode 8a (also serving as the signal electrode) is
Overcoat layer 12 and second overcoat layer 13
And the distance that the drain electrode 8a and the pixel electrode 14 do not affect each other can be maintained, and at the same time, the overcoat layer in the contact hole 19 portion is constituted only by the second overcoat layer. A sufficient transmittance can be maintained without attenuating the light of the backlight during operation.

The CFonTFT substrate of this embodiment is formed by the following method. A gate electrode 5b, a gate insulating film 6, a semiconductor layer 15, a drain electrode 8a, a passivation film 9, and a black matrix 11 are sequentially formed on the transparent insulating substrate 4 on the TFT substrate 1 side by using a photoresist method or the like. I do. After that, the first overcoat layer 12 is formed using a photoresist method. As the overcoat material used at this time, a photosensitive resist composed of an acrylic resin or the like is used.
The photosensitive resist is applied by a coating method such as a spin coating method or a printing method capable of obtaining a uniform film thickness, and is exposed, developed, and baked to form a first overcoat layer 12. At this time, the opening 29 for accommodating the color filter formed in the next step is formed in the first overcoat layer 12. The first overcoat layer 12 is formed to have a thickness of several μm depending on the dielectric constant of a film used on the drain electrode 8a or on the drain electrode 8a and the gate electrode 5b.

Next, a color filter 10 which is a photosensitive acrylic resin resist is applied to the surface of the substrate by a printing method, and exposure, development and baking are successively performed to form the first filter formed in the previous step. The color filter 10 is embedded in the opening 29 of the overcoat layer 12. At this time, a color filter is opened in a region where the contact hole 19 is formed so that the color filter is not formed.

After that, like the first overcoat layer 12, a second overcoat layer 13 as a flattening film is formed of a photosensitive resist composed of an acrylic resin or the like by a spin coating method, a printing method, or the like. It is formed by applying, exposing, developing, and baking by a coating method capable of obtaining a uniform thickness. afterwards,
In order to form the contact hole 19, the passivation film 9 exposed in the opening 29 is removed by using a photoresist method, and the contact hole 1 is formed in the passivation film 9.
9 is formed.

Next, a pixel electrode 14 connected to the source electrode 8b through the contact hole 19 is formed on the second overcoat layer 13.

As described above, the wirings such as the drain electrode 8a (signal electrode) and the data line 7 and the color filter 10
CFonTF with different overcoat layer thickness
A T substrate can be obtained.

Embodiment 4 Next, an active matrix type liquid crystal display device according to a fourth embodiment of the present invention and a method for manufacturing the same will be described with reference to FIG. FIG.
FIG. 2 is a cross-sectional view illustrating a structure of the liquid crystal display device according to the embodiment. This embodiment is different from the second embodiment only in the vertical relationship between the black matrix and the first overcoat layer. Therefore, the structure and manufacturing method other than the black matrix and the first overcoat layer are the same as those of the third embodiment.

On the transparent insulating substrate 4 on the TFT substrate 1 side,
A gate electrode 5b, a gate insulating film 6, a semiconductor layer 15, a drain electrode 8a, and a passivation film 9 are formed. On this semiconductor layer 15, a first overcoat layer 12 is provided, on which a black matrix 1 is further formed.
1 is formed. The second overcoat layer 1 is formed under the pixel electrode 14 via the contact hole 19.
3. A color filter 10 is formed. Also, in this embodiment, as in the third embodiment, the color filter 10 is formed on the first overcoat layer 1 formed first.
2 are formed inside. In this embodiment, the first and second overcoat layers use a photosensitive acrylic resin.

In this embodiment, as in the third embodiment, the distance between the drain electrode 8a and the pixel electrode 14 so as not to affect each other can be maintained. Since only the overcoat layer 2 is used, sufficient transmittance can be maintained without attenuating the light of the backlight during operation.

The CFonTFT substrate of this embodiment is formed by the following method. A gate electrode 5b, a gate insulating film 6, a semiconductor layer 15, a drain electrode 8a, a passivation film 9, and a first overcoat layer 12 are formed on the transparent insulating substrate 4 on the TFT substrate 1 side by a photoresist method or the like. To sequentially pattern the film. The overcoat layer used at this time is a photosensitive resist composed of an acrylic resin or the like, and is applied by a coating method such as a spin coating method or a printing method capable of obtaining a uniform film thickness, and is exposed, developed, and fired. Form.

Thereafter, a black matrix 11 is formed by a photoresist method. Here, the first overcoat layer 12 and the black matrix 11 are formed so as to have substantially the same plane pattern, and an opening 29 for accommodating the color filter 10 is formed.

Next, a color filter 10 which is a photosensitive acrylic resin resist is applied to the first overcoat layer 1.
Application is performed using a printing method in the same manner as in 2, and exposure, development, and baking are performed to bury the first overcoat layer 12 and the opening 29 of the black matrix 11. At this time, the color filter 10 is not formed in the contact hole 19 part, but the opening 29 is formed.

Subsequently, similarly to the first overcoat layer 12, a second overcoat layer 13 as a flattening film is formed of a photosensitive resist composed of an acrylic resin or the like by a spin coating method or a printing method. For example, it is applied by a coating method capable of obtaining a uniform film thickness, and is formed by exposure, development, and baking. At this time, as in the case of the color filter 10, the second overcoat layer 13 is not formed in the contact hole 19 but an opening 29 is formed.

Thereafter, the passivation film 9 exposed in the opening 29 is removed by using a photoresist method to form a contact hole 19 in the passivation film 9. A CFonT having a TFT-side transparent pixel electrode 301 formed thereon and having a different overcoat film thickness on the wiring and on the opening.
An FT substrate can be obtained.

Next, a pixel electrode 14 connected to the source electrode 8b through the contact hole 19 is formed on the second overcoat layer 13.

As described above, the wirings such as the drain electrode 8a (signal electrode) and the data line 7 and the color filter 10
CFonTF with different overcoat layer thickness
A T substrate can be obtained.

Embodiment 5 Next, an active matrix type liquid crystal display device and a method of manufacturing the same according to a fifth embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a cross-sectional view showing the structure of the liquid crystal display device of the present embodiment, and FIG. 10 is a plan view showing the position of a spacer for forming a gap between substrates. This embodiment is characterized in that the step formed by the formation of the first overcoat layer is positively used to facilitate the formation of the spacer for adjusting the gap.

Generally, in a liquid crystal display device, a TFT substrate 1
In order to maintain an interval between the substrate and the counter substrate 2, usually, a spherical spacer ball is scattered to form a gap of about 3 to 4.5 μm. However, when the gap is formed using the spacer ball, the uniformity of the gap is impaired due to the unevenness of the substrate at the portion where the spacer ball is arranged. Therefore, in order to accurately control the gap, it is necessary to form the columnar spacer 20 at a predetermined position on the substrate by patterning.

In this case, a columnar spacer 20 is formed by applying a negative photosensitive acrylic resin or the like to a thickness of about 3 to 5 μm, exposing, developing, and firing. In particular, when exposure is performed using a ghi mixed line or a gh mixed line, a pattern cannot be formed accurately because the depth of focus differs depending on the wavelength of each g line or i line.
Of the columnar spacer 2
In some cases, 0 may collapse and a gap may become non-uniform.

However, in the liquid crystal display device of this embodiment, as shown in the first and second embodiments, T
Since the thick first overcoat layer 12 is formed in the FT portion, the TFT portion is higher than in the prior art.
The height of the columnar spacer 20 formed thereon can be reduced by positively utilizing the step generated on T.

Specifically, the first overcoat layer 12
As a result, a step of 1-2 μm is formed on the TFT, so that the thickness of the resin for forming the columnar spacer 20 is 1 to
It can be suppressed to about 2 μm. Therefore, even when exposure is performed using the ghi mixed line or the gh mixed line, patterning into an accurate shape can be performed, and the problem that the columnar spacer 20 is collapsed can be prevented. In addition,
In the case of the structure of this embodiment, the columnar spacer 20 is formed at the position shown in FIG. 10 in order to use the step of the first overcoat layer 12.

Embodiment 6 Next, an active matrix liquid crystal display device and a method of manufacturing the same according to a sixth embodiment of the present invention will be described with reference to FIGS. FIG. 11 and FIG. 12 are cross-sectional views showing the structure of the liquid crystal display device of this embodiment. In the present embodiment, the first overcoat layer on the TFT is formed higher and is used as a spacer for forming a gap, thereby eliminating the columnar spacer forming step and simplifying the step.

The liquid crystal display device of this embodiment is the same as the second embodiment.
Similarly to the embodiment, a switching element such as a TFT 17 is formed on the transparent insulating substrate 4, and a color filter 10 and a black matrix 11 are formed thereon via a passivation film 9. Then, the first overcoat layer 12 is formed so as to cover the black matrix 11 of the TFT 17.
At this time, the viscosity of the acrylic positive photosensitive resin or the like used as the first overcoat layer 12 is increased.

Then, a second overcoat layer 13 is formed thereon, and as shown in FIG. 11, the thickness obtained by adding the first and second overcoat layers 12 and 13 is equal to the desired gap. The thickness of the first overcoat layer 12 is adjusted to be substantially equal, and the second overcoat layer 13 is brought into contact with the opposing substrate 2 when the opposing substrate 2 is bonded, whereby the columnar spacer 20 is formed. The gap can be accurately controlled without separately forming the gap.

Further, in order to form the pattern of the first overcoat layer 12 more reliably, it is necessary to prevent the thickness of the first overcoat layer 12 from becoming too large. Therefore, as shown in FIG. 12, the first overcoat layer 12 is formed by stacking two or three color filters 10 below the black matrix 11 and increasing the film thickness.
Can be reduced in thickness. In this case, the first overcoat layer 12 is
Is preferably formed so as to cover the side surface of the color filter 10 to protect the color filter 10.

Embodiment 7 Next, an active matrix type liquid crystal display device according to a seventh embodiment of the present invention and a method for manufacturing the same will be described with reference to FIGS. FIG. 13 is a cross-sectional view showing the structure of the liquid crystal display device of this example, and FIGS. 14 and 15 are process cross-sectional views showing a method for manufacturing the same. This embodiment provides a manufacturing method for realizing the structure of the first embodiment with a small number of steps. That is, in the above-described embodiment, since the first overcoat layer 12 and the second overcoat layer 13 are separately formed, application of resin, exposure,
Each process such as development is required twice, but the first and second overcoat layers 12 and 13 can be integrally formed by the following manufacturing method in order to reduce the number of steps. The method will be described below.

First, as in the first embodiment, a switching element such as a TFT 17 is formed on the transparent insulating substrate 4, and a color filter 10 and a black matrix 11 are formed thereon via a passivation film 9. (See FIGS. 14A and 14B). Next, the overcoat layer 2
In this embodiment, since a thick film portion and a thin film portion are formed by one type of overcoat layer, for example, an acrylic positive photosensitive resin having a viscosity of about 15 cp is rotated at a rotational speed of 800 rpm /. It is applied in about 10 seconds, and the film thickness is 1
It is about μm.

In this embodiment, exposure is performed using a method as shown in FIG. That is, a light-shielding film 22 for completely shielding light is provided in a portion where the thick overcoat layer 25a on the black matrix 11 is to be left, and a halfway is provided in a portion where the thin overcoat layer 25b such as on the color filter 10 is to be left. Overcoat layer 2 having permeable film 23 and above contact hole 19
5 are completely removed by using a transparent gray-tone mask 21 to irradiate U
By controlling the degree of V light and changing the etching rate of each part with respect to the developing solution, it is possible to obtain a predetermined film thickness of each part.

More specifically, the translucent film 23 is irradiated with 1 J of UV light by transmitting 50% as a semi-transmissive film 23, and then TMAH
After developing with 0.4% solution and baking at 220 ° C for 1 hour,
The overcoat layer 25a has a thickness of about 1 μm on the black matrix 11, and the overcoat layer 25b has a thickness of about 0.5 μm on the color filter 10 (see FIG. 15D).
Thereafter, as shown in FIG. 15E, a pixel electrode made of ITO or the like is formed, and the TFT substrate 1 is formed.

As described above, the exposure amount is changed depending on the location using the gray tone mask 21 to form an overcoat layer thicker on the TFT 17 and thinner on the color filter 10 in the pixel region by one exposure and development. Therefore, the number of steps can be reduced as compared with the above embodiments. In this embodiment, the exposure amount is adjusted using the gray tone mask 21. However, the exposure is performed twice, and the exposure amount is changed, so that the overcoat layer having a different film thickness can be overcoated once. It can also be formed by applying and developing a resin.

Embodiment 8 Next, an active matrix type liquid crystal display device according to an eighth embodiment of the present invention and a method for manufacturing the same will be described with reference to FIG. FIG.
FIG. 2 is a cross-sectional view illustrating the structure of the liquid crystal display device of the present example. This embodiment is characterized in that the second overcoat layer 13 is omitted and only the first overcoat layer 12 is used.

That is, similarly to the first embodiment, the TFT 17 is formed on the transparent insulating substrate 4, and the color filter 10 and the black matrix 11 are formed thereon via the passivation film 9. Then, the first overcoat layer 12 is applied, and T / T
The first overcoat layer 12 is formed on the black matrix 11 of the FT 17 part and the data line 7 part.
By adjusting the exposure amount and the development time, the first overcoat layer 12 on the flat portion of the color filter 10 is removed, and the first overcoat layer 12 is formed on the step portion (TFT 17 portion, data line 7 portion, edge portion of the color filter 10). Of the overcoat layer 12 is left.

According to such a method, the black matrix 11 can be protected and the first overcoat layer 12 can be left at the edge of the color filter 10. Therefore, even if the second overcoat layer 13 is not provided. Disconnection of the pixel electrode 14 can be prevented. In this case, the color filter 10 is exposed to the liquid crystal layer 3 through the ITO, and the impurities of the color filter 10 are likely to be mixed into the liquid crystal. A device that eliminates it is necessary.

In each of the above embodiments, the CF on TFT
Although the liquid crystal display device having the structure has been described, the present invention is not limited to the above embodiment, and the color filter 10
Also, the present invention can be applied to a structure in which the black matrix 11 is formed on the counter substrate side.

[0100]

As described above, according to the active matrix type liquid crystal display device and the method of manufacturing the same of the present invention, the first thick film having high viscosity is formed on the black matrix.
By providing a second overcoat layer of a thin film having a low viscosity on the color filter, the surface of the black matrix is sufficiently covered and protected, and the second overcoat layer on the color filter is provided. A decrease in transmittance due to the coat layer can be suppressed.

Further, by forming a thick first overcoat layer also on the data line, the distance between the data line and the pixel electrode can be increased, whereby the coupling between the data line and the pixel electrode can be increased. Capacity can be reduced,
The display quality can be improved.

Further, by actively utilizing the thick first overcoat layer formed on the TFT portion, the height of the columnar spacer formed thereon can be reduced, or the overcoat layer itself can be used as a spacer. Can be used.
This can prevent the problem that the columnar spacer collapses, and can omit the step of separately forming the columnar spacer.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a liquid crystal display device of the present invention.

FIG. 2 is a plan view showing a configuration of the liquid crystal display device according to the first embodiment of the present invention.

FIG. 3 is a plan view illustrating a configuration of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 4 is a sectional view showing the structure of the liquid crystal display device according to the first embodiment of the present invention.

FIG. 5 shows T of the liquid crystal display device according to the first embodiment of the present invention.
FIG. 7 is a process cross-sectional view illustrating the method of manufacturing the FT substrate 1.

FIG. 6 is a cross-sectional view illustrating a structure of a liquid crystal display device according to a second embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a structure of a liquid crystal display device according to a third embodiment of the present invention.

FIG. 8 is a cross-sectional view illustrating a structure of a liquid crystal display device according to a fourth embodiment of the present invention.

FIG. 9 is a sectional view showing the structure of a liquid crystal display according to a fifth embodiment of the present invention.

FIG. 10 is a plan view illustrating a configuration of a liquid crystal display device according to a fifth embodiment of the present invention.

FIG. 11 is a sectional view showing a structure of a liquid crystal display device according to a sixth embodiment of the present invention.

FIG. 12 is a sectional view showing a structure of a liquid crystal display device according to a sixth embodiment of the present invention.

FIG. 13 is a sectional view showing a structure of a liquid crystal display according to a seventh embodiment of the present invention.

FIG. 14 is a process sectional view illustrating the method for manufacturing the TFT substrate 1 of the liquid crystal display device according to the seventh embodiment of the present invention.

FIG. 15 is a process sectional view illustrating the method for manufacturing the TFT substrate 1 of the liquid crystal display device according to the seventh embodiment of the present invention.

FIG. 16 is a sectional view showing a structure of a liquid crystal display device according to an eighth embodiment of the present invention.

FIG. 17 is a cross-sectional view illustrating a structure of a conventional liquid crystal display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 TFT substrate 2 Counter substrate 3 Liquid crystal layer 4 Transparent insulating substrate 5 Gate line 5a Gate terminal 5b Gate electrode 6 Gate insulating film 7 Data line 7a Data terminal 8a Drain electrode 8b Source electrode 9 Passivation film 10 Color filter 11 Black matrix 12th 1 overcoat layer 13 second overcoat layer 14 pixel electrode 15 semiconductor layer 16 counter electrode 17 TFT 18 pixel capacitance 19 contact hole 20 columnar spacer 21 graytone mask 22 light shielding film 23 semi-transmissive film 24 flattening film 25 overcoat Layer 25a Thick overcoat layer 25b Thin overcoat layer 29 Opening

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09F 9/30 338 G09F 9/30 338 5G435 349 349B 349C 9/35 9/35 H01L 21/336 H01L 49 / 02 29/786 29/78 612D 49/02 619A 619B (72) Inventor Takayuki Ishino 2080 Onoharacho, Izumi-shi, Kagoshima Kagoshima Nippon Electric Co., Ltd. (72) Inventor Yuji Yamamoto 7-1, Shiba 5-chome, Minato-ku, Tokyo No. Within NEC Corporation (72) Inventor Mamoru Okamoto 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation (72) Inventor Shigeru Shimo 5-7-1 Shiba, Minato-ku, Tokyo Japan Inside Electric Company (72) Inventor Shinichi Nakata 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation Inside (72) Inventor Masanobu Hidehira Minato-ku, Tokyo 5-7-1, Shiba, NEC Corporation (72) Inventor Yoshitaka Horie 5-7-1, Shiba, Minato-ku, Tokyo Inside (72) Inventor Shoichi Kuroba Shiba, Minato-ku, Tokyo 5-7-1, NEC Corporation F-term (reference) 2H089 LA09 LA11 LA12 NA05 NA14 QA14 QA16 2H090 HA04 HA05 HB03X HB07X HC05 HC11 HD03 HD06 2H092 JB51 JB57 JB58 KB22 KB24 KB25 KB26 NA07 NA19 NA27 AC09A A08 AA43 AA47 AA48 AA53 BA03 BA43 CA19 CA24 DA09 DA13 DB01 DB04 EA04 EB02 EC03 ED03 ED15 FA01 FA02 GB10 5F110 AA21 BB01 CC01 CC05 CC07 DD02 EE03 EE04 EE44 FF02 FF03 FF09 FF29 GG02 NN33 NN24 NN23 NN24 NN24 NN36 NN45 NN52 NN73 QQ02 QQ06 5G435 AA03 AA04 AA07 AA17 BB12 CC09 CC12 FF13 GG12 HH18 HH20 KK05

Claims (23)

[Claims] 1. A liquid crystal is sandwiched between a pair of substrates disposed opposite to each other, and a plurality of gate lines and data lines crossing each other are provided on one side of the substrate and near an intersection region of the gate lines and the data lines. A thin film transistor provided, a color filter disposed in each pixel region surrounded by the gate line and the data line, and an overcoat layer covering the surface of the one side substrate including the thin film transistor and the color filter. An active matrix liquid crystal display device, wherein the overcoat layer is formed such that a film thickness on the color filter is smaller than a film thickness on a region excluding the color filter. Matrix type liquid crystal display device. 2. The active matrix type liquid crystal display device according to claim 1, wherein said overcoat layer has a structure in which a plurality of overcoat layers are laminated on a region excluding said color filter. 3. A liquid crystal is sandwiched between a pair of substrates disposed opposite to each other. A plurality of gate lines and data lines intersecting each other are provided on one side of the substrate, and a plurality of gate lines and data lines intersect each other. An active comprising: a thin film transistor provided; a color filter disposed in each pixel surrounded by the gate line and the data line; and an overcoat layer covering the surface of the one side substrate including the thin film transistor and the color filter. A matrix-type liquid crystal display device, wherein the overcoat layer includes a first overcoat layer and a second overcoat layer, and only the second overcoat layer is provided on the color filter. An active matrix type liquid crystal display device characterized in that: 4. A liquid crystal is interposed between a pair of substrates disposed opposite to each other, and a plurality of gate lines and data lines crossing each other are provided on one side of the substrate, and a plurality of gate lines and data lines intersect each other in the vicinity of the intersection region of the gate lines and the data lines. A thin film transistor provided, a color filter disposed in each pixel region surrounded by the gate line and the data line, and an overcoat layer covering the surface of the one side substrate including the thin film transistor and the color filter. An active matrix liquid crystal display device, wherein the overcoat layer includes a first overcoat layer and a second overcoat layer, and only the second overcoat layer is provided on the color filter. An active matrix type liquid crystal display device characterized in that: 5. A liquid crystal is sandwiched between a pair of substrates disposed opposite to each other, and a plurality of gate lines and data lines crossing each other are provided on one side of the substrate and near an intersection region of the gate lines and the data lines. A thin film transistor provided, a color filter disposed in each pixel region surrounded by the gate line and the data line, and an overcoat layer covering the surface of the one side substrate including the thin film transistor and the color filter. An active matrix liquid crystal display device, wherein the overcoat layer has a first overcoat layer and a second overcoat layer, and the color filter is formed between the first overcoat layers. The second overcoat layer is formed so as to cover the surface of the one side substrate including the color filter and the first overcoat layer. An active matrix liquid crystal display device characterized by being formed. 6. A spacer formed on a convex portion including the thin film transistor and the overcoat layer, and a gap between opposing substrates is defined by the convex portion and the spacer. 6. The active matrix liquid crystal display device according to any one of 5. 7. The film thickness of the overcoat layer is set such that a convex portion formed including the thin film transistor and the overcoat layer is in contact with an opposing substrate, and the thickness of the overcoat layer is set between the opposing substrates. The active matrix liquid crystal display device according to claim 1, wherein the gap is defined as: 8. The active matrix type liquid crystal display device according to claim 1, wherein a black matrix is formed on said thin film transistor region. 9. The active matrix type liquid crystal display device according to claim 8, wherein said color filter is formed on said thin film transistor region. 10. The active matrix liquid crystal display device according to claim 1, wherein a black matrix is formed on said data lines. 11. A step of forming a thin film transistor in each pixel region surrounded by the gate line and the data line together with a plurality of gate lines and data lines crossing each other on the first substrate; Disposing a color filter in each pixel region surrounded by the gate line and the data line; forming an overcoat layer so as to cover the surface of the one side of the substrate including the color filter; An active matrix type comprising: a step of forming a pixel electrode on a coat layer; and a step of arranging a second substrate on the first substrate so as to face the liquid crystal and holding liquid crystal between the first and second substrates. A method of manufacturing a liquid crystal display device, wherein, when forming the overcoat layer, the overcoat layer on the color filter is more than the overcoat layer in another region. A method for manufacturing an active matrix type liquid crystal display device, characterized in that it is formed thin. 12. The overcoat layer is formed by spin-coating a plurality of overcoat layers, and the overcoat layer on the color filter is provided with an overcoat layer having a lower viscosity than overcoat layers in other regions. An active matrix type liquid crystal display device according to claim 11, which is used. 13. The overcoat layer is formed by spin-coating a plurality of overcoat layers, and the overcoat layer on the color filter is spin-coated at a higher rotation speed than the overcoat layers in other regions. An active matrix liquid crystal display device according to claim 11, wherein the liquid crystal display device is formed. 14. A step of forming a thin film transistor in each pixel region surrounded by the gate line and the data line, together with a plurality of gate lines and data lines crossing each other on the first substrate; Arranging a color filter in each pixel region surrounded by the gate line and the data line;
Forming an overcoat layer so as to cover the surface of the substrate, forming a pixel electrode on the overcoat layer, disposing a second substrate on the first substrate, and forming the first and second substrates. 2. A method of manufacturing an active matrix type liquid crystal display device, comprising: holding a liquid crystal between two substrates, wherein the step of forming the overcoat layer comprises a first overcoat layer and a second overcoat. A method for manufacturing an active matrix liquid crystal display device, wherein the method is performed by sequentially forming layers, and the second overcoat layer is formed so as to cover the color filter. 15. A step of forming a thin film transistor in each pixel region surrounded by the gate line and the data line together with a plurality of gate lines and data lines crossing each other on the first substrate; Arranging a color filter in each pixel region surrounded by the gate line and the data line;
Forming an overcoat layer so as to cover the surface of the substrate, forming a pixel electrode on the overcoat layer, disposing a second substrate on the first substrate, and forming the first and second substrates. 2. A method of manufacturing an active matrix type liquid crystal display device, comprising: holding a liquid crystal between two substrates, wherein the step of forming the overcoat layer is performed on a surface of the first substrate excluding the color filter. An active matrix type liquid crystal display device comprising: forming a first overcoat layer; and forming a second overcoat layer thinner than the first overcoat layer on the color filter. Production method. 16. The first overcoat layer and the second overcoat layer.
16. The method for manufacturing an active matrix liquid crystal display device according to claim 15, wherein the overcoat layer is formed in one step by changing the exposure amount of each overcoat layer portion. 17. The method of manufacturing an active matrix type liquid crystal display device according to claim 16, wherein the adjustment of the exposure amount is performed in one step by using a gray-tone mask including a light-shielding portion, a semi-transmissive portion, and a transmissive portion. Method. 18. A step of forming a thin film transistor in each pixel region surrounded by the gate line and the data line together with a plurality of gate lines and data lines crossing each other on the first substrate; Arranging a color filter in each pixel region surrounded by the gate line and the data line;
Forming an overcoat layer so as to cover the surface of the substrate, forming a pixel electrode on the overcoat layer, disposing a second substrate on the first substrate, and forming the first and second substrates. 2. A method of manufacturing an active matrix liquid crystal display device, comprising: holding a liquid crystal between two substrates, wherein the step of forming the overcoat layer comprises the steps of: forming a first overcoat layer; Forming the first overcoat layer, wherein the step of forming the first overcoat layer is performed between the step of forming the thin film transistor and the step of forming the color filter. The step of forming the color filter is performed by forming a first overcoat layer on the surface of the first substrate excluding a formation region, The step of forming the second overcoat layer is performed by forming a color filter between the coat layers, and the step of forming the color filter is performed between the step of forming the color filter and the step of forming the pixel electrode. A method for manufacturing an active matrix liquid crystal display device, wherein the method is performed by covering a surface of the first substrate including a color filter and the first overcoat layer with a second overcoat layer. 19. After forming a convex portion including the thin film transistor and the overcoat layer, the first portion is formed on the convex portion.
19. The method of manufacturing an active matrix liquid crystal display device according to claim 11, wherein a spacer for defining a gap between the second substrate and the second substrate is formed. 20. When forming a convex portion including the thin film transistor and the overcoat layer, the convex portion contacts the second substrate to define a gap between the first and second substrates. 19. The method for manufacturing an active matrix liquid crystal display device according to claim 11, wherein the thickness of the overcoat layer is adjusted. 21. The method of manufacturing an active matrix type liquid crystal display device according to claim 11, wherein a black matrix is formed on said thin film transistor region. 22. The method according to claim 21, wherein the color filter is formed on the thin film transistor region. 23. The method of manufacturing an active matrix type liquid crystal display device according to claim 11, wherein a black matrix is formed on said data lines.