JP2000171793A - Manufacture of liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a liquid crystal display device with high display quality which enables manufacturing a reflection plate with excellent reflection characteristics easily and with excellent reproducibility. SOLUTION: A negative photosensitive resin 9 is coated on a substrate 1. In the first region of the photosensitive resin 9, projecting and recessing parts are formed on the surface by exposure with various integral values of irradiated light quantity resulting in differences of the remaining film quantity of the photosensitive resin 9. In the second region of the photosensitive resin 9, a recessing part is formed by exposure with an integral value of irradiated light quantity different from that in the first region resulting in the remaining film quantity of the photosensitive resin 9 less than that in the first region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method of manufacturing a liquid crystal display device which performs display by reflecting externally incident light.

[0002]

2. Description of the Related Art In recent years, applications of liquid crystal display devices to word processors, laptop personal computers, pocket televisions, and the like have been rapidly advancing. In particular, among liquid crystal display devices, a reflective liquid crystal display device that performs display by reflecting light incident from the outside does not require a backlight, and thus consumes low power, is thin, and can be reduced in weight. Attention has been paid.

However, the conventional reflection type liquid crystal display device has a problem that the brightness and contrast of the display are affected by the use environment or use conditions such as the ambient brightness. At present, great expectations are placed on the realization of a reflective liquid crystal display device which has good reflection characteristics, can be manufactured easily and with good reproducibility, and has high display quality.

Here, Japanese Patent Application Laid-Open No. 6-75238 discloses a technique for randomly and densely generating irregularities on a reflective electrode in order to improve the display quality of a reflective liquid crystal display device.

[0005] In this method, a resin layer for adding fine irregularities to the reflective electrode is composed of a first photosensitive resin layer on which random irregularities are patterned, and a second photosensitive resin layer for further smoothing the irregularities. And a mask for patterning the first photosensitive resin, wherein circular light-shielding portions are randomly arranged, and the area of the light-shielding region is set to 40% or more of the area of the reflection plate. It is to do.

[0006] By increasing the randomness in this way, interference due to repeated patterns is prevented,
It is described that the coloring of the reflected light is avoided and the density of the irregularities is increased to reduce the flat portion and reduce the regular reflection component.

[0007] Japanese Patent Application Laid-Open No. 9-90426 discloses that
In order to shorten the manufacturing process of the reflection type liquid crystal display device, there is disclosed a technique for simultaneously exposing a pattern for forming unevenness and a contact hole using only one layer of a positive photosensitive resin.

Here, a method of manufacturing the reflection type liquid crystal display device described in this publication will be briefly described with reference to the drawings.

FIG. 14 is a sectional view showing the structure of a reflection type liquid crystal display device manufactured based on the manufacturing method described in the above-mentioned publication, and FIG. 15 shows a flow of the manufacturing process. It is sectional drawing.

As shown in FIG. 14, the reflection type liquid crystal display device described in the above-mentioned publication uses a substrate on which a liquid crystal driving element 24 is formed as a reflection substrate 23.
Pixel electrode 10, a transparent electrode 12 opposed thereto, a color filter substrate 25 supporting the transparent electrode 12, and a liquid crystal 11 interposed therebetween.
And a retardation plate 15 disposed above the color filter substrate (on the side not facing the liquid crystal), and a polarizing plate 16 disposed on the retardation plate 15.

The reflection substrate 23 has a structure in which an amorphous silicon transistor is formed as a liquid crystal driving element 24 on the glass substrate 1. As shown in FIG. Ta as the gate electrode 2 on the substrate 1, SiNx as the gate insulating layer 3, a-Si as the semiconductor layer 4, n-type a-Si as the n-type semiconductor layer 5, Ti as the source electrode 7,
The drain electrode 8 is made of Ti or the like.

Here, the manufacturing process of the reflective substrate 23 of the reflective liquid crystal display device described in the above-mentioned publication will be described.
This will be described with reference to FIG.

First, as shown in FIG.
A positive photosensitive resin 9 is applied thereon.

Next, as shown in FIG.
Exposure at high illuminance is performed using a contact hole 30 as shown in FIG. 1 as a transmission portion and a photomask having a transmission portion 18 in the uneven portion.

Next, as shown in FIG. 15C, by performing development with a developing solution, the resin in the above-described exposed portion is completely removed, and a positive resin shape is formed with respect to the mask pattern. You.

Next, as shown in FIG. 15D, by performing a heat treatment, the resin in the exposed area is deformed due to the heat dripping phenomenon, so that a smooth uneven shape is obtained. However,
The exposed area at this time is flat because the resin has been completely removed by the developing step described above.

Next, as shown in FIG. 15E, an Al thin film is formed as the reflective electrode 10, and patterning is performed so that one reflective electrode 10 corresponds to one transistor.

In the reflection type liquid crystal display device described in the above-mentioned publication, the reflection electrode 10 is formed by the above-described steps. Is completely removed to form a concave-convex shape, resulting in a reflector having many flat portions. In such a reflective plate having many flat portions, the light source is transferred to the flat region, and therefore, the reflective plate has many regular reflection components. When the light source is reflected, it is difficult to confirm the display. Therefore, in general, there is a tendency to avoid a specular reflection component when viewing a reflective display device.

Therefore, the specular reflection component of the reflection plate in the reflection type liquid crystal display device disclosed in the above-mentioned publication does not contribute to brightness, but results in dark display.

[0020]

In contrast to the reflection type liquid crystal display device disclosed in Japanese Patent Application Laid-Open No. 9-90426 as described above, the above-mentioned Japanese Patent Application Laid-Open No. 6-75238 discloses an unevenness of the reflection plate. There has been disclosed a reflective liquid crystal display device that employs a complicated unevenness forming process in order to create an ideal scattering state by increasing the density. This means that after applying the first positive photosensitive resin, perform first exposure and development with sufficient strength,
After completely patterning the concavo-convex shape, fill the gaps of the concavo-convex into smooth irregularities, apply a second positive photosensitive resin to reduce the flat part, and then expose only the contact hole part with the second exposure Development is performed and patterning is performed again.

However, in such a process,
Since the two layers of the photosensitive resin are stacked, it is apparent that the photo process (coating-exposure-development-heat treatment) of the photosensitive resin is required twice, resulting in an increase in cost.

Further, in the reflection type liquid crystal display device disclosed in Japanese Patent Application Laid-Open No. 9-90426, one layer of a positive photosensitive resin is used, so that only one photo process of the photosensitive resin is required. Although it is a simple process and it is possible to reduce the cost, it is necessary to remove the photosensitive resin in the contact hole part surely, so it is inevitable that the positive photosensitive resin Therefore, the area to be exposed becomes a flat surface and becomes a reflector having a small unevenness density and a large amount of regular reflection.

Further, if dust or the like is present in an exposed region for removing the photosensitive resin, the unexposed portion cannot be removed by development. Therefore, poor conduction is likely to occur in the contact hole and the signal input terminal portion.

The present invention has been made to solve the above-mentioned problems in the reflection type liquid crystal display device, and an object of the present invention is to provide a liquid crystal display device which is unlikely to cause conduction failure and has good reflection characteristics. An object of the present invention is to provide a method for manufacturing a liquid crystal display device that can easily produce a display device with good reproducibility.

[0025]

According to a method of manufacturing a liquid crystal display device of the present invention, an incident light from the other substrate is placed on one of a pair of substrates opposed to each other with a liquid crystal layer interposed therebetween. A method of manufacturing a liquid crystal display device having a reflection means for reflecting light, a step of applying a negative photosensitive resin on the one substrate, and an integrated value of an exposure amount for irradiating a first region of the photosensitive resin. By changing the amount of exposure, the residual film amount of the photosensitive resin is changed to form irregularities on the surface. In the second region of the photosensitive resin, the integrated value of the first region and the exposure amount to be irradiated is calculated. A step of forming a concave portion having a smaller remaining film amount than the first region of the photosensitive resin by exposing differently, a step of developing the exposed photosensitive resin, and a step of developing the exposed photosensitive resin. A heat treatment step and forming a reflective film on the photosensitive resin after the heat treatment That the steps are characterized in that it comprises, by its, the above-described object can be attained.

At this time, a reflection electrode made of the reflection film is formed in the first region of the photosensitive resin, and the reflection electrode is formed below the reflection electrode in the second region of the photosensitive resin. It is desirable to be connected to the wiring.

Preferably, a terminal portion is formed in a non-display region on the one substrate, and a second region of the photosensitive resin is formed in the terminal portion.

Further, the step of exposing the photosensitive resin comprises:
Exposing using a photomask having a transmissive portion, a light shielding portion, and a semi-transmissive portion, forming the first region in a region corresponding to the transmissive portion and the semi-transmissive portion of the photomask, It is preferable that the second region is formed in a region corresponding to the light shielding portion.

Further, the step of exposing the photosensitive resin comprises:
Exposing using a first photomask; and exposing using a second photomask, wherein the first and second photomasks are used to expose the first region and the second region.
It is desirable to form each region.

At this time, it is preferable that the step of exposing using the first photomask and the step of exposing using the second photomask have the same amount of light to be irradiated.

In the step of exposing using the first photomask, uniform and low illuminance exposure is performed and the second photomask is exposed.
In the step of exposing using the photomask described above, it is desirable to perform uniform and high illuminance exposure.

In the second photomask, circular or polygonal regions are irregularly arranged, and the total area of the circular or polygonal region is 20% of the total area of the photomask. % Or more and 40% or less.

It is preferable that the circular or polygonal regions arranged on the second photomask are irregularly arranged such that the distance between the centers of gravity of adjacent regions is in the range of 5 μm to 50 μm.

The operation of the method for manufacturing a liquid crystal display device according to the present invention will be described below.

According to the present invention, a region having a different pattern of the photosensitive resin applied on the substrate is exposed by dividing the integrated value of the exposure amount in area, thereby obtaining a smooth and high-density uneven shape. And other regions can be formed in fewer steps.

In other words, since the photosensitive resin can be curved by the heat treatment step in a state where there is no portion where the photosensitive resin is completely removed, the flat portion hardly exists in the unevenness forming region. Therefore, it is possible to realize good reflection characteristics with a reduced specular reflection component.

Here, in the exposure step, a circular or polygonal column or hole may be formed since the negative photosensitive resin in the portion shielded by the photomask (light shielding region) is easily dissolved in the developing solution. In addition, since the negative photosensitive resin in a portion (transmission region) that is not shaded by the photomask is hardly dissolved in the developing solution, the photosensitive resin is developed with the developing solution after the exposure, so that the light is transmitted through the photomask. Irregular photosensitive resin is formed on the substrate corresponding to the region and the light-shielding region.

By using a photosensitive resin as an interlayer insulating film, the number of steps can be reduced as much as possible to manufacture a reflective electrode. And the first of the photosensitive resin
By forming a reflective electrode in the region and connecting the reflective electrode to a wiring formed below the reflective electrode in the second region of the photosensitive resin, that is, to connect the reflective electrode to the liquid crystal driving element. Since the resin in the area corresponding to the contact hole is removed, the photosensitive resin remains over the entire display picture element area excluding the contact hole, so that there are few flat parts and smooth unevenness is formed over the entire picture element area It is possible to obtain bright reflected light with reduced regular reflection.

Also, the photosensitive resin acts as an interlayer insulating film, and the second region of the photosensitive resin forms a transmission region corresponding to a terminal portion for inputting an external signal, thereby reducing the number of processes. Is reduced as much as possible to manufacture the terminal portion.

The method also includes the step of exposing using a photomask having a transmissive portion, a light-shielding portion, and a semi-transmissive portion, wherein a first region is formed in a region corresponding to the transmissive portion and the semi-transmissive portion of the photomask. By forming the second region in a region corresponding to the light shielding portion of the mask, the number of exposures can be reduced to one.

The method also includes a step of exposing using a first photomask and a step of exposing using a second photomask, wherein the first and second photomasks are used to expose a first region and a second region. Is formed, it is possible to use a photomask composed of only the transmission part and the light-shielding part, and the design and manufacture of the photomask are simple, and the number of exposure steps can be reduced.

At this time, by performing the exposure using the first photomask and the exposure using the second photomask, respectively, with the same irradiation light amount, the adjustment of the light amount is simplified, so that the throughput of the exposure step is improved. be able to.

In the step of exposing using the first photomask, uniform and low illuminance exposure is performed, and in the step of exposing using the second photomask, uniform and high illuminance exposure is performed. Since it is possible to irradiate only high-illumination exposure to a region where a convex portion is formed in one region,
In the first region, the photosensitive resin can be completely left completely. Here, the high illuminance exposure is an exposure amount such that the crosslinking of the resin in the negative photosensitive resin is sufficiently advanced, and the remaining film amount after development is larger than approximately 50% of the film thickness before development. In addition, the low-illumination exposure means that the crosslinking of the resin is not sufficiently performed in the negative photosensitive resin,
The residual film amount after development is larger than 0% and 50% of the film thickness before development.
The exposure amount is less than 10%, preferably 10% or more and less than 50%.

More specifically, the negative photosensitive resin formed on the substrate is subjected to low-illumination exposure using the first photomask, thereby performing low-illumination exposure using the first photomask. Since the cross-linking of the photosensitive resin in the exposed portion is not sufficiently performed, the low-illuminance exposed portion is uniformly reduced in thickness by development with the developing solution after exposure.

The negative photosensitive resin formed on the substrate is exposed to high illuminance using the second photomask, so that the portion exposed to high illuminance using the second photomask is exposed. The cross-linking of the photosensitive resin proceeds sufficiently, so that the projection with the developing solution after the exposure forms a projection that is one step higher than the unexposed portion by the second photomask. This makes it possible to form a smooth uneven shape.

As described above, after one layer of the negative photosensitive resin is exposed to high illuminance and exposed to low illuminance and developed, the photosensitive resin is subjected to a heat treatment so that the substrate can be heated. The unevenly shaped photosensitive resin formed on the substrate is deformed by heat dripping, and a continuous high-density and smooth uneven surface without a plane portion is formed on the substrate.

Further, by forming a reflective electrode on a photosensitive resin having a smooth uneven surface after the heat treatment, it is possible to manufacture a good reflecting means having a small regular reflection component.

In the present invention, the first exposure step and the second exposure step
The order of the exposure step may be reverse to the order described above.

In the process from the exposure step to the development step, exposure (low-light exposure and high-light exposure) —development process and exposure (low-light exposure or high-light exposure) —
Development-exposure (high illuminance exposure or low illuminance exposure) -development processes are conceivable, and either process is possible in the present invention, but the former process is desirable in terms of simplification of the process.

In the second photomask, circular or polygonal regions are irregularly arranged, and the total area of the circular or polygonal region is 20% of the total area of the photomask.
% Or more and 40% or less, and the circular or polygonal regions are irregularly arranged, so that the irregularity pattern of the photosensitive resin formed on the substrate has no periodicity,
The light interference phenomenon can be prevented, and as a result, white scattered light without coloring can be obtained. In addition, since the scattered light from the uneven surface is not biased in a specific direction, uniform scattered light can be obtained.

Since the total area of the circular or polygonal region in the second photomask is set to 20% or more and 40% or less of the total area of the photomask, the light can be efficiently used on the substrate. It is possible to control the inclination angle of the uneven shape of the photosensitive resin formed on the substrate.

Here, the total area of the photomask specifically refers to the total area of the reflective electrode. If the circular or polygonal area of the second photomask is set to 40% or more, the circular or polygonal area is obtained. When polygonal areas are randomly arranged, circular or polygonal areas adjacent to each other overlap to form a large pattern, the overall pattern density decreases, the ratio of flat parts increases, and regular reflection occurs. It becomes a reflection plate with many. Further, when the circular or polygonal area in the second photomask is set to 20% or less, when circular or polygonal areas are randomly arranged, the distance between adjacent circular or polygonal areas is increased. The distance between the convex portion and the convex portion or the concave portion and the concave portion of the shape of the photosensitive resin formed by development is separated, and a flat portion is formed between the convex portion and the convex portion or the concave portion and the concave portion when heat is applied by heating. It remains and becomes a reflection plate with much regular reflection. From these points,
In the present invention, the total area of the circular region in the second photomask is set to 20% or more and 40% or less of the total area of the photomask.

In the circular or polygonal region arranged on the second photomask, the distance between the centers of gravity of adjacent regions is irregularly arranged within the range of 5 μm or more and 50 μm or less, so that one picture of the liquid crystal display device can be obtained. It is possible to arrange a sufficient number of uneven patterns for the pixels, and it is possible to obtain scattered light having no characteristic difference between picture elements.

Here, if adjacent circular or polygonal areas are arranged so as not to overlap with each other, a pattern having a center of gravity interval of 5 μm or less is not resolved but becomes a flat portion and has a large number of regular reflections due to the resolution limit of the stepper. It becomes a reflector. In general, in a liquid crystal display device, since one picture element size is about 100 μm × 300 μm or less, about 10 or more projections or depressions are arranged in one picture element in order to obtain uniform scattering. In order to achieve this, the center of gravity
If the distance between the centers of gravity is larger than 50 μm, the interval between the circular regions is wide, so that the ratio of the flat portions becomes large, resulting in a reflector having a large amount of regular reflection. From such a point, in the present invention, the circular or polygonal regions arranged in the second photomask are arranged such that the distance between the centers of gravity of adjacent circular or polygonal regions is 5 μm or more and 50 μm or more.
The arrangement was irregular so as to be within m or less.

[0055]

(Embodiment 1) Hereinafter, a reflection type liquid crystal display device according to Embodiment 1 of the present invention will be described.
This will be described with reference to the drawings. FIG. 1 is a plan view showing a reflective substrate in a reflective liquid crystal display device according to the present embodiment, FIG. 2 is a cross-sectional view of the reflective substrate shown in FIG. 1, and FIG. FIG. 4 is a cross-sectional view showing the flow of FIG.

As shown in FIG. 1 and FIG. 2, a reflective electrode 10 is formed on a reflective substrate 23 used in the reflective liquid crystal display device according to the present embodiment, and the surface thereof has a circular concave or convex shape. The portion 33 has a smooth uneven shape. Then, an amorphous silicon transistor is formed as the liquid crystal driving element 24 on the glass substrate 1. The liquid crystal driving element 24 includes Ta as the gate electrode 2 on the glass substrate 1, SiNx as the gate insulating layer 3, a-Si as the semiconductor layer 4, n-type a-Si as the n-type semiconductor layer 5, T as source electrode 7
i, the drain electrode 8 is made of Ti or the like.

The signal input terminal 27 for inputting a signal to the gate bus line and the source bus line is
The gate bus line is composed of two layers: a terminal electrode 2 made of Ta and patterned at the same time as the gate electrode, and a terminal connection electrode 26 made of ITO.

Here, a manufacturing process of the reflection substrate 23 of the reflection type liquid crystal display device according to the present embodiment will be described with reference to FIG. In the figure, a pixel area is shown on the left side, and a signal input terminal area is shown on the right side.

First, as shown in FIG. 3A, a negative photosensitive resin 9 (product name: FE301) is placed on a glass substrate 1.
N: Fuji Film Ohlin) is applied to a thickness of 1 to 5 μm. In the present embodiment, the coating was performed with a thickness of 3 μm.

Next, as shown in FIG. 4, using a first photomask 19 in which a light shielding portion 18 corresponding to the contact hole portion 30 is arranged, as shown in FIG. Exposure was performed uniformly at low illuminance in the area excluding. The exposure amount at this time is 20 mj to 100 mj.
However, in the present embodiment, exposure was performed with an exposure amount of 40 mj.

Next, as shown in FIG. 5, a circular area is formed in the area excluding the contact hole 30 to form the transmission section 17.
Using a second photomask 20 having an area of 20% or more and 40% or less, as shown in FIG. 3C, the region excluding the contact hole 30 was uniformly exposed with high illuminance. The exposure amount at this time is preferably from 160 mj to 500 mj, but in the present embodiment, exposure was performed with an exposure amount of 240 mj. In this case, the circular or polygonal transmission portions 17 of the second photomask are randomly arranged such that the center interval between adjacent transmission portions 17 is 5 μm or more and 50 μm or less, preferably 10 μm to 20 μm. Was used.

At this time, the first and second photomasks have such a structure that the signal input terminal 27 is also shielded from light in the same manner as the contact hole is shielded from light.

Next, as shown in FIG. 3 (d), development is performed with TMAH (tetramethylammonium hydroxide) manufactured by Tokyo Ohka Kogyo Co., Ltd. The resin in the hole portion and the signal input terminal portion) is completely removed, and the resin in the low illuminance exposed portion is about 40% of the initial film thickness.
%, And the resin in the high illuminance exposed portion was in a state of remaining about 80% of the initial film thickness.

Next, as shown in FIG.
By performing the heat treatment for 60 minutes, the resin in the above-mentioned state was deformed due to the heat dripping phenomenon, resulting in a smooth uneven shape.

Next, as shown in FIG. 3 (f), an Al thin film is formed on the substrate 1 as the reflective electrode 10 to a thickness of 2000 ° by a sputtering method, and as shown in FIGS. 3 (g) to 3 (k). Then, patterning was performed so that one reflective electrode 10 corresponds to one transistor.

Specifically, as shown in FIG. 3 (g), a photoresist 28 is applied, and as shown in FIG.
The exposed portion and the signal input terminal portion 27 for separation for each pixel electrode are exposed, and as shown in FIGS. 3 (i) to 3 (k), development, etching and peeling are performed to form the reflection electrode 10. Patterning of the Al electrode was performed.

By the steps described above, a reflective electrode 10 having smooth and high-density uneven portions was formed. Such a reflection substrate 23 has a reduced flat portion, and can realize ideal reflection characteristics with a small regular reflection component. In addition, the number of photo processes for the photosensitive resin can be reduced, and the cost required for manufacturing the reflection plate can be reduced.

Finally, the reflection substrate 23 and the color filter substrate supporting the transparent electrode are bonded together via a spacer in the same manner as in the prior art, and liquid crystal is injected, and the phase difference plate is attached to the color filter substrate. The reflective liquid crystal display device of the present embodiment was completed by attaching a polarizing plate.

(Embodiment 2) Hereinafter, a reflective liquid crystal display device according to Embodiment 2 of the present invention will be described with reference to the drawings. Note that the reflective substrate included in the reflective liquid crystal display device according to the present embodiment is the same as the reflective substrate shown in FIG. 1, but the manufacturing method is different.
This will be described below with reference to the cross-sectional view shown in FIG.

FIG. 6 is a cross-sectional view showing a manufacturing process of a reflection substrate used in the reflection type liquid crystal display device according to the present embodiment. In FIG. 6, a pixel region is shown on the left side, and a signal region is shown on the right side. 3 shows an input terminal area.

First, as shown in FIG. 6A, a negative photosensitive resin 9 (product name: FE301) is placed on a glass substrate 1.
N: Fuji Film Ohlin) is applied to a thickness of 1 to 5 μm. In the present embodiment, the coating was performed with a thickness of 3 μm.

Next, as shown in FIG. 7, the transmissive portion 17, the light-shielding portion 18, and the other semi-transmissive portion 29 are mixed, and the area of the transmissive portion 17 is 20% or more and 40% or less as a circular region. As shown in FIG. 6B, exposure was performed uniformly at a high illuminance using the photomask 35 as described above. The exposure amount at this time is preferably from 160 mj to 500 mj, but in this embodiment, the exposure was performed with an exposure amount of 240 mj. In addition,
At this time, the area of the circular or polygonal transmission part 17 of the photomask is 30%, and the center distance between adjacent transmission parts 17 is 5 μm or more and 50 μm or less, preferably 10 μm to 20 μm.
μm, and a light-shielding portion 18 in a region corresponding to the contact hole 30 and a semi-transmissive portion having a light transmittance of 17% of the transmissive portion in other regions. 29 were used. Although not shown, the area other than the display area has a light shielding area.

The subsequent steps are the same as in the first embodiment described above, and development is performed as shown in FIG.
By performing the heat treatment as shown in (d), a smooth uneven shape was formed by the heat dripping phenomenon.

Then, as shown in FIG.
An Al thin film is formed as a reflective electrode 10 thereon, and FIG.
As shown in FIG.
Patterning was performed so that one reflective electrode 10 corresponded.

Through the steps described above, the reflective electrode 10 having smooth and high-density uneven portions was formed. Such a reflection substrate 23 has a reduced flat portion, and can realize ideal reflection characteristics with a small regular reflection component. In addition, the number of photo processes for the photosensitive resin can be reduced, and the cost required for manufacturing the reflection plate can be reduced.

Finally, in the same manner as in the prior art, the reflection substrate 23 and the color filter substrate supporting the transparent electrode are adhered through a spacer, and liquid crystal is injected, and the phase difference is applied to the color filter substrate. The reflection type liquid crystal display device in the present embodiment was completed by attaching the plate and the polarizing plate.

In the reflection type liquid crystal display device according to the present embodiment, a reflection electrode having smooth and high-density reflection irregularities is formed in the same manner as in the first embodiment. By using a photomask having a semi-transmissive portion in a photo process, the number of times of exposure can be further reduced, and the cost required for manufacturing a reflective substrate can be reduced.

Embodiment 3 Hereinafter, a reflective liquid crystal display device according to Embodiment 3 of the present invention will be described with reference to the drawings. Note that the reflective substrate included in the reflective liquid crystal display device according to the present embodiment is the same as the reflective substrate shown in FIG. 1, but the manufacturing method is different.
This will be described below with reference to the cross-sectional view shown in FIG.

FIG. 8 is a cross-sectional view showing a manufacturing process of a reflection substrate used in the reflection type liquid crystal display device according to the present embodiment. In the drawing, a pixel region is shown on the left side, and a signal region is shown on the right side. 3 shows an input terminal area.

First, as shown in FIG. 8A, a negative photosensitive resin 9 (product name: FE301) is placed on a glass substrate 1.
N: Fuji Film Ohlin) is applied to a thickness of 1 to 5 μm. In the present embodiment, the coating was performed with a thickness of 3 μm.

Next, as shown in FIG. 5, a circular region is formed in the region excluding the contact hole portion 30 to form the transmission portion 17.
Using a second photomask 20 having an area of 20% or more and 40% or less, as shown in FIG. 8B, the region excluding the contact hole 30 was uniformly exposed at low illuminance. The exposure amount at this time is preferably 20 mj to 100 mj, but in the present embodiment, the exposure was performed with an exposure amount of 40 mj. At this time, the circular or polygonal transmission part 17 of the second photomask is connected to the adjacent transmission part 17.
Is 5 μm or more and 50 μm or less, preferably 10 μm or less.
Those randomly arranged so as to have a size of 20 μm to 20 μm were used.

Next, as shown in FIG. 4, using a first photomask 19 in which a light shielding portion 18 corresponding to the contact hole portion 30 is arranged, as shown in FIG. Area except for the first
Exposure was performed at the same exposure amount of 40 mj as in the exposure step of No. 1. The first and second photomasks have a structure in which the signal input terminal 27 is also shielded from light, similarly to the light-shielded state of the contact holes.

Next, as shown in FIG. 8 (d), development is performed with TMAH (tetramethylammonium hydroxide) manufactured by Tokyo Ohka Kogyo Co., Ltd. Portion and the signal input terminal portion) are completely removed, and the resin in the portion exposed once remains about 30% of the initial film thickness, and the resin in the portion exposed twice. Was in a state of remaining about 70% of the initial film thickness.

Next, as shown in FIG.
By performing the heat treatment for 60 minutes, the resin in the above-mentioned state was deformed due to the heat dripping phenomenon, resulting in a smooth uneven shape.

The subsequent steps are the same as those in the first and second embodiments described above. As shown in FIG. 8F, an Al thin film is formed on the substrate 1 as the reflective electrode 10, and FIG.
As shown in (k), patterning was performed such that one reflective electrode 10 corresponds to one transistor.

By the steps described above, a reflective electrode 10 having smooth and high-density uneven portions was formed. Such a reflection substrate 23 has a reduced flat portion, and can realize ideal reflection characteristics with a small regular reflection component. In addition, the number of photo processes for the photosensitive resin can be reduced, and the cost required for manufacturing the reflection plate can be reduced.

Lastly, the reflection substrate 23 and the color filter substrate supporting the transparent electrode are adhered to each other through a spacer in the same manner as in the prior art, and liquid crystal is injected. The reflection type liquid crystal display device in the present embodiment was completed by attaching the plate and the polarizing plate.

In the reflection type liquid crystal display device according to the present embodiment, a reflection electrode having smooth and high-density reflection irregularities is formed as in the first embodiment. By equalizing the first and second exposures during the photo process, the throughput of the apparatus is improved, and the cost required for manufacturing the reflective substrate can be reduced.

Embodiment 4 Hereinafter, a transflective liquid crystal display device according to Embodiment 4 of the present invention will be described.
This will be described with reference to the drawings. 9 is a plan view showing a substrate in a transflective liquid crystal display device according to the present embodiment, FIG. 10 is a cross-sectional view of the substrate shown in FIG. 9, and FIG. FIG. 4 is a cross-sectional view showing the flow of FIG.

As shown in FIGS. 9 and 10, the substrate 23 used in the transflective liquid crystal display device according to the present embodiment has one pixel electrode formed on the substrate 23 as the reflective electrode 10. Are divided into a reflection region where a transparent electrode is formed and a transmission region 31 where a transparent electrode is formed. And
Like the first to third embodiments, the surface of the reflective electrode 10 has a smooth, high-density unevenness formed of circular concave portions or convex portions.

With such a structure, in a transmission type liquid crystal display device, if the ambient light is strong enough to haze the display,
It can be used as a reflective liquid crystal display device, but if it is difficult to see the display with a reflective liquid crystal display device in a dim environment, turn on the backlight and use it as a transmissive liquid crystal display device Can be.

The transmission-reflection type liquid crystal display device according to the present embodiment has a configuration in which an amorphous silicon transistor is formed as a liquid crystal driving element 24 on a glass substrate 1 as shown in FIGS. Has become. The liquid crystal driving element 24 is composed of Ta as the gate electrode 2 on the glass substrate 1 and SiN as the gate insulating layer 3.
x, a-Si as the semiconductor layer 4, n-type a-Si as the n-type semiconductor layer 5, a source electrode 7 and a drain electrode 8 made of ITO, and a Ta layer 32 laminated thereon. It should be noted that the ITO of the drain electrode 8 extends to the pixel region to form a transparent electrode configured as a transmission region.

The signal input terminal 27 for inputting signals to the gate bus lines and the source bus lines is not shown in the present embodiment, but is the same as in the first to third embodiments. .

Here, the manufacturing process of the substrate 23 of the transflective liquid crystal display device according to the present embodiment will be described with reference to FIG. In FIG. 11, ITO existing in the transmission region 31 is omitted.

First, as shown in FIG. 11A, a negative photosensitive resin 9 (product name: OFPR-
800: manufactured by Tokyo Ohka) to a thickness of 1 to 5 μm.
In the present embodiment, the coating was performed with a thickness of 3 μm.

Next, as shown in FIG. 12, a first photomask 34 in which the light-shielding portions 18 corresponding to the contact hole portions 30 and the transmission regions 31 are arranged is used.
As shown in (b), the contact hole portion 30 and the transmission region 31 were uniformly exposed at low illuminance. At this time, the first and second photomasks have a structure in which the signal input terminal portion 27 is also shielded from light, as in the light-shielded state of the contact hole. The exposure amount at this time is 20 m
j to 100 mj, but in the present embodiment,
Exposure was performed with an exposure amount of mj.

Next, as shown in FIG. 13, using a second photomask 36 in which the transmissive portion 17 is arranged as a circular region so as not to exist in the contact hole portion 30 and the transmissive region 31, As shown in FIG. 11C, exposure was performed uniformly at high illuminance. The exposure amount at this time is 160 mj
In the present embodiment, exposure is performed with an exposure amount of 240 mj using the second photomask 36 in which the area of the transmission part 17 is 30%. In this case, the circular or polygonal transmission portion 17 of the second photomask 36 has a reflection electrode having an area of 30% of the area of the reflection electrode and a center interval between adjacent transmission portions 17 of 5 μm or more and 50 μm or less, preferably 10 μm to 20 μm. What was arranged at random so that it might be used.

Next, as shown in FIG. 11D, development was performed with TMAH (tetramethylammonium hydroxide) manufactured by Tokyo Ohka Kogyo Co., Ltd., which is a developing solution, so that the above-described exposed portion (contact hole) was developed. Portion, the transmission region, and the signal input terminal portion) are completely removed, the resin in the low illuminance exposed portion remains about 40% of the initial film thickness, and the resin in the unexposed portion is the initial film. About 80% of the film thickness remained.

Next, as shown in FIG.
By performing the heat treatment at 60 ° C. for 60 minutes, the resin in the above-described state was deformed due to the heat dripping phenomenon, resulting in a smooth uneven shape. Was.

The subsequent steps are the same as those of the first to third embodiments.
As in FIG. 3, as shown in FIG. 11F, an Al thin film was formed on the substrate 1 as the reflective electrode 10, and patterning was performed so that one reflective electrode 10 corresponded to one transistor.

By the steps described above, a substrate having a reflective region composed of the reflective electrode 10 having smooth and high-density uneven portions and a transmissive region composed of the transparent electrode was formed. The reflective electrode of such a substrate has a reduced flat portion, and can realize ideal reflection characteristics with a small specular reflection component. In addition, the number of photo processes for the photosensitive resin can be reduced, and the cost required for manufacturing the reflection plate can be reduced.

Finally, the substrate 2 is formed in the same manner as in the prior art.
3 and a color filter substrate supporting a transparent electrode are bonded via a spacer, a liquid crystal is injected, a retardation plate and a polarizing plate are bonded to the color filter substrate, and a backlight is provided on the back of the substrate. The transmission and reflection type liquid crystal display device of the present embodiment was completed by installing the liquid crystal display device.

[0103]

According to the present invention, a single layer of photosensitive resin applied on a substrate is exposed by dividing the area and varying the integrated value of the amount of exposure, so that the photosensitive resin is smooth and high. It is possible to form an uneven shape having a high density, and it is possible to reduce the flat portion and to manufacture an ideal reflecting means having a small regular reflection component. Therefore, it is possible to reduce the number of photo processes for the photosensitive resin and to reduce the cost required for manufacturing.

In the present invention, since the negative photosensitive resin is used, it is possible to remove the unexposed portion of the resin due to dust and the like by development. Even if dust adheres to the section and the signal input terminal section, it is possible to reliably ensure conduction.

[Brief description of the drawings]

FIG. 1 is a plan view of a reflective substrate used in a reflective liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a reflective substrate used in a reflective liquid crystal display device according to the embodiment of the present invention.

FIGS. 3A to 3K are cross-sectional views illustrating a process of manufacturing a reflective substrate used in a reflective liquid crystal display device according to an embodiment of the present invention.

FIG. 4 is a schematic plan view showing a pattern of a transmission region and a light shielding region of the first photomask according to the embodiment of the present invention.

FIG. 5 is a schematic plan view showing a pattern of a transmission region and a light shielding region of a second photomask according to the embodiment of the present invention.

FIGS. 6A to 6J are cross-sectional views showing the steps of manufacturing a reflective substrate used in a reflective liquid crystal display device according to an embodiment of the present invention.

FIG. 7 is a schematic plan view showing a pattern of a photomask according to the embodiment of the present invention.

8 (a) to 8 (k) are cross-sectional views illustrating a process for manufacturing a reflective substrate used in a reflective liquid crystal display device according to an embodiment of the present invention.

FIG. 9 is a plan view of a reflective substrate used in a transflective liquid crystal display device according to an embodiment of the present invention.

FIG. 10 is a cross-sectional view of a reflective substrate used in a transflective liquid crystal display device according to an embodiment of the present invention.

FIGS. 11A to 11F are cross-sectional views illustrating a process for manufacturing a reflective substrate used in a transflective liquid crystal display device according to an embodiment of the present invention.

FIG. 12 is a first embodiment of the present invention.
FIG. 4 is a schematic plan view showing a pattern of a transmission region and a light shielding region of the photomask of FIG.

FIG. 13 is a second embodiment of the present invention.
FIG. 4 is a schematic plan view showing a pattern of a transmission region and a light shielding region of the photomask of FIG.

FIG. 14 is a cross-sectional view showing a reflective liquid crystal display device manufactured by a conventional manufacturing method.

FIGS. 15A to 15E are cross-sectional views illustrating a process of manufacturing a reflective substrate in a conventional reflective liquid crystal display device.

FIG. 16 is a schematic plan view showing a pattern of a transmission region and a light shielding region of a conventional photomask.

[Explanation of symbols]

Reference Signs List 1 glass substrate 2 gate line, gate electrode, terminal electrode made of the same material as gate electrode 3 gate insulating film 4 semiconductor layer 5 n + layer 6 etch stopper 7 source line, source electrode 8 drain electrode 9 interlayer insulating film (photosensitive resin) REFERENCE SIGNS LIST 10 reflective electrode 11 liquid crystal layer 12 ITO electrode 13 color filter 14 color filter side glass substrate 15 retardation plate 16 polarizing plate 17 transmission part 18 light shielding part 19 first photomask 20 second photomask 21 photomask 22 UV light 23 Reflective substrate 24 Liquid crystal driving element 25 Color filter substrate 26 Terminal connection electrode 27 Signal input terminal 28 Photoresist 29 Semi-transmissive part 30 Contact hole 31 Transmissive area 32 Metal layer 33 Concave or convex part 34 First photomask 35 Photo Mask 36 Second Fo Mask

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Ohgami 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka F-term (reference) 2H091 FA14Y FA31Y FB02 FC10 FC22 GA02 GA13 LA12 2H092 JA28 JA41 JA46 JB52 KA05 KA12 KB25 MA16 NA01 NA15 NA29 PA12

Claims (9)

[Claims] 1. A method of manufacturing a liquid crystal display device, comprising: a reflecting means for reflecting incident light from the other substrate side on one of a pair of substrates arranged to face each other with a liquid crystal layer interposed therebetween. Applying a negative photosensitive resin on the one substrate; and exposing the first region of the photosensitive resin to the first region of the photosensitive resin by changing the integrated value of the amount of exposure to be irradiated, thereby forming a residual film of the photosensitive resin. The first region of the photosensitive resin is exposed by varying the amount of light to form irregularities on the surface, and exposing the second region of the photosensitive resin to the first region with a different integrated value of the amount of exposure to be irradiated. A step of forming a concave portion having a smaller remaining film amount than the above, a step of developing the photosensitive resin after the exposure, a step of heating the photosensitive resin after the development, and a step of heating the photosensitive resin. Forming a reflective film on the liquid crystal display device Manufacturing method. 2. A reflection electrode formed of the reflection film is formed in a first region of the photosensitive resin, and the reflection electrode is formed below the reflection electrode in a second region of the photosensitive resin. The method according to claim 1, wherein the method is connected to a wiring. 3. A terminal portion is formed in a non-display region on the one substrate, and a second region of the photosensitive resin is formed in the terminal portion.
3. The method for manufacturing a liquid crystal display device according to item 1. 4. The step of exposing the photosensitive resin includes the step of exposing using a photomask having a transmissive portion, a light-shielding portion, and a semi-transmissive portion, corresponding to the transmissive portion and the semi-transmissive portion of the photomask. 2. The method according to claim 1, wherein the first region is formed in a region to be formed, and the second region is formed in a region corresponding to a light shielding portion of the photomask. 5. The method according to claim 1, wherein the step of exposing the photosensitive resin comprises:
Exposing using a photomask and exposing using a second photomask, wherein the first and second regions are respectively formed by the first and second photomasks. The method for manufacturing a liquid crystal display device according to claim 1, wherein: 6. The method according to claim 5, wherein the step of exposing using the first photomask and the step of exposing using the second photomask are performed with the same amount of light. The manufacturing method of the liquid crystal display device according to the above. 7. A step of performing uniform and low illuminance exposure in the step of exposing using the first photomask, and performing a uniform and high illuminance exposure in the step of exposing using the second photomask. A method for manufacturing a liquid crystal display device according to claim 5, wherein: 8. A circular or polygonal region is irregularly arranged on the second photomask,
8. The method according to claim 7, wherein a total area of the circular or polygonal region is 20% to 40% of a total area of the photomask. 9. The circular or polygonal region arranged on the second photomask is arranged irregularly when the distance between the centers of gravity of adjacent regions is in the range of 5 μm or more and 50 μm or less. A method for manufacturing the liquid crystal display device according to claim 8.