JP2003156766A - Reflection type liquid crystal display unit and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a switching element from having characteristic deterioration in manufacturing processes and to decrease the number of manufacturing processes. SOLUTION: A reflection type liquid crystal display unit is equipped with a glass substrate 53, a transparent electrode 55 provided on the glass substrate 53, a glass substrate 40, a thin-film transistor 44 provided on the glass substrate 40, an insulating film 45 which is provided on the thin-film transistor 44 and has an uneven structure 45a formed on its surface, a reflection electrode 48 which is provided in a shape on which the uneven structure 45a is reflected and connected to the thin-film transistor 44, and a liquid crystal layer 56 which is sandwiched between the transparent electrode 55 and the reflection electrode 48. The insulating film 48 protects the thin-film transistor 44 after it is formed and areas differing in film thickness are irregularly arranged to form the uneven structure 45a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type liquid crystal display device having a reflection plate that reflects the light transmitted from the outside through a liquid crystal layer to the outside again, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Reflective liquid crystal display devices are mainly used for portable terminals because they can achieve lower power consumption, thinner and lighter weight than transmissive liquid crystal display devices. The reason is that light reflected from the outside can be used as a display light source by being reflected by a reflection plate inside the device, so that no backlight is required.

The basic structure of the current reflective liquid crystal display device is
Liquid crystal using TN (twisted nematic) system, single polarizing plate system, STN (super twisted nematic) system, GH (guest host) system, PDLC (polymer dispersion) system, cholesteric system, etc. It is composed of a switching element for driving the liquid crystal display and a reflector provided inside or outside the liquid crystal cell. These general reflection type liquid crystal display devices use thin film transistors (T
FT) or metal / insulating film / metal structure diode (MI
M) is used as a switching element to adopt an active matrix driving method capable of realizing high definition and high image quality, and a structure in which a reflector is attached to this is adopted.

FIG. 36 is a sectional view showing a conventional one-polarizing plate type reflection type liquid crystal display device. Hereinafter, description will be given with reference to this drawing.

The counter substrate 1 includes a polarizing plate 2, a retardation plate 3,
It is composed of a glass substrate 4, a color filter 5, a transparent electrode 6 and the like. The lower substrate 7 includes a glass substrate 8, a thin film transistor 9 having an inverted stagger structure, which is a switching element formed on the glass substrate 8, a convex shape 10 made of an insulating film serving as a base of a concave-convex structure, and an interlayer formed thereon. It is composed of a polyimide film 11 which is an insulating film, a reflection electrode 13 which is connected to the source electrode 12 of the thin film transistor 9 and functions as a reflection plate and a pixel electrode, and the like. The liquid crystal layer 14 is located between the counter substrate 1 and the lower substrate 7.

The light source uses the reflected light 16. Reflected light 16
Means that the incident light 15 from the outside is the polarizing plate 2, the phase difference plate 3,
It passes through the glass substrate 4, the color filter 5, the transparent electrode 6, and the liquid crystal layer 14, and is reflected by the reflective electrode 13.

The display performance of this reflective liquid crystal display device is
A bright and white display is required in the liquid crystal transmission state. In order to realize this display performance, it is necessary to efficiently emit incident light 15 from various directions to the front. Therefore, by forming the concavo-convex structure on the polyimide film 11, the reflecting electrode 13 located thereon can have a scattering function. Therefore, control of the concavo-convex structure of the reflective electrode 13 is important for determining the display performance of the reflective liquid crystal display device.

37 and 38 are sectional views showing a method of manufacturing a reflective electrode in a conventional reflective liquid crystal display device. Hereinafter, description will be given with reference to this drawing.

In the thin film transistor manufacturing process, first, the gate electrode 21 is formed on the glass substrate 20 (FIG. 37).
[A]). Then, the gate insulating film 22, the semiconductor layer 23,
A doping layer 24 is formed (FIG. 37 [b]). Subsequently, the island 2 of the semiconductor layer 23 and the doping layer 24
5 is formed (FIG. 37 [c]), and the source electrode 26 and the drain electrode 27 are formed (FIG. 37 [d]). Then, the manufacturing process of the reflective electrode is performed.

In the manufacturing process of the reflective electrode, first, the organic insulating film 28 having photosensitivity is formed (FIG. 37 [e]). Then, the convex portion 29 is formed in the reflection electrode formation region by performing photolithography (FIG. 37 [f]), and the convex portion 29 is melted by heating to be converted into a smooth convex shape 30 (FIG. 38 [g]. ]). Subsequently, by covering the upper part with the organic insulating film 31, a smoother uneven surface 32 is formed (FIG. 38 [h]). Subsequently, a contact portion 33 for electrically connecting the reflective electrode to the source electrode of the thin film transistor is formed (FIG. 38 [i]), and then the reflective electrode 34 is formed (FIG. 38 [j]). The method for manufacturing the reflective electrode is described in, for example, Japanese Examined Patent Publication No. 61-6390, or Tohru koizum.
i and Tatsuo Uchida, Proceedings of the SID, Vol.2
9,157,1988).

[0011]

As described above, the concavo-convex structure of the insulating film located under the reflective electrode in the conventional reflective liquid crystal display device uses an organic insulating film or an inorganic insulating film having photosensitivity. It is formed by forming a convex portion serving as a base and then covering the convex portion with an organic insulating film or an inorganic insulating film.

However, since metal wirings, electrodes, switching elements, etc. are formed under the convex portions, the metal wirings, electrodes, switching elements, etc. are exposed to the etching solution in the etching process for forming the convex portions. It will be.
As a result, the characteristics of the switching element are deteriorated due to the reaction between the etching liquid and the base film, and the reliability of the switching element is deteriorated due to the residual etching liquid.

When an organic insulating film or an inorganic insulating film having no photosensitivity is used as the insulating film below the reflective electrode, a photoresist pattern is formed on the insulating film and a convex pattern is formed by dry etching. . In this case, since the underlying film is exposed to plasma during the etching process, plasma damage causes deterioration of switching element characteristics.

On the other hand, the manufacturing of the conventional reflection type liquid crystal display device requires a large number of steps as described above. Therefore, the unit cost of the reflective liquid crystal display device has increased due to the increase in manufacturing cost. The reason why the reflective liquid crystal display device requires a large number of manufacturing steps is that a high performance switching element and a high performance reflective plate are formed on the same insulating substrate in order to obtain a bright and high quality display. Further, it is because it is necessary to use a method capable of forming the concave-convex structure on the surface of the reflector in a desired shape in the production of the high-performance reflector. Therefore, in the conventional reflective liquid crystal display device, a large number of film formation steps and PR
A (photoresist) process, an etching process and the like have been required.

On the other hand, at present, no effective means for simplifying the manufacturing process has been adopted. Again, the concavo-convex structure located under the reflective electrode is manufactured as follows.
First, a photosensitive resin is applied and formed, and the photosensitive resin is patterned by an exposure process and a development process to form a convex pattern. However, the photosensitive resin film is completely removed in the region where the convex pattern is not formed. Then, the convex pattern is subjected to heat treatment to be converted into a convex shape having roundness, and in order to create a desired smooth uneven surface, an organic insulating layer is formed by coating so as to cover the convex pattern.

That is, the insulating film below the reflective electrode is composed of two layers, a film having a convex shape and a film covered therewith. The insulating film has a function as an interlayer insulating film that electrically insulates the reflective electrode from the switching element and the wiring. After that, after forming a contact hole in this insulating layer, a metal thin film such as aluminum is deposited, and this metal thin film is patterned to obtain a reflective electrode reflecting the fine uneven shape of the insulating film.

As described above, in the formation of the reflective electrode, 1) a step of forming an insulating film for forming a convex portion which becomes a base, and 2)
Convex portion forming step, 2) insulating film forming step on the convex portion pattern,
Five steps are required: 3) a contact hole forming step, 4) a high reflection efficiency metal thin film forming step, 5) a reflective electrode forming step.

[0018]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to realize high brightness and high quality display performance by preventing the characteristic deterioration of the switching element during the manufacturing process, and to reduce the manufacturing cost by reducing the number of manufacturing processes. It is an object of the present invention to provide a reflective liquid crystal display device and a method for manufacturing the same that realize the above.

[0019]

A reflection type liquid crystal display device of the present invention which solves the above problems is a transparent first substrate, a transparent electrode provided on the first substrate, and a second substrate. When,
A switching element provided on the second substrate, an insulating film provided on the switching element and having an uneven structure on the surface, and provided on the insulating film in a shape reflecting the uneven structure. In addition, a reflective electrode connected to the switching element, and a liquid crystal layer sandwiched between the transparent electrode side of the first substrate and the reflective electrode side of the second substrate are provided. The insulating film protects the switching element after the switching element is formed, and the uneven structure is formed by irregularly arranging regions having different film thicknesses.

In the conventional reflection type liquid crystal display device, since the convex shape is located on the metal wiring, the electrode, the switching element, etc., the underlying portion is exposed to the process atmosphere when the convex portion is formed. , The switching element and the like were damaged, and as a result, the characteristics of the switching element deteriorated. On the other hand, the insulating film in the present invention is
Since the metal wiring, the electrode, the switching element, etc. are always covered, the metal wiring, the electrode, the switching element, etc. are not exposed to the process atmosphere at the time of forming the concavo-convex structure, so that these can be prevented from the process damage.
Further, in the insulating film of the present invention, the concavo-convex structure is composed of regions having different film thicknesses, that is, a region having a large film thickness is a convex portion and a region having a thin film thickness is a concave portion. Therefore, another film is not required for the concavo-convex structure, and the number of steps is reduced.

Further, since the reflection type liquid crystal display device according to the present invention has the continuous reflection electrode having a smooth shape and a concavo-convex structure, bright display is possible. This is because the brightness of the reflective liquid crystal display device is determined by the tilt angle of the uneven structure of the reflective electrode.

The insulating film having the concavo-convex structure may be a single layer film made of the same material. If the insulating film is a single layer and is formed in the same process, it is not necessary to form the concavo-convex structure part of the insulating film and the interlayer insulating part in separate steps. Therefore, complicated concavo-convex formation in the conventional reflective liquid crystal display device is performed. The process is simplified.

Further, the insulating film having the uneven structure may have a light absorbing property. Thereby, the light incident from between the adjacent reflective electrodes can be absorbed by the insulating film. Therefore, since it is possible to block the incident light that circulates to the back surface of the reflective electrode, it is possible to suppress the irradiation of the incident light to the switching element, and it is possible to realize good switching characteristics.

The concavo-convex structure may have a plurality of protrusions arranged irregularly. As a result, the interference of the reflected light from the reflective electrode can be suppressed, so that the concavo-convex structure having good reflection performance can be formed. Furthermore, the protrusions of the concavo-convex structure may be formed in an island-shaped or linear planar shape. Thereby, a bright reflection performance is obtained. That is, the reflective liquid crystal display device using these uneven structures is
Bright display performance can be obtained.

The concavo-convex structure may have a plurality of recesses arranged irregularly. As a result, the interference of the reflected light from the reflective electrode can be suppressed, so that the concavo-convex structure having excellent reflector performance can be formed. Further, the concave portion of the concavo-convex structure may have a hole-shaped or linear planar shape. Thereby, a bright reflection performance is obtained. That is, the reflective liquid crystal display device using these uneven structures is
Bright display performance can be obtained.

Further, the concavo-convex structure may be formed by repeating irregular concavo-convex shapes in units of one pixel or in units of two or more pixels. As a result, the interference of reflected light can be suppressed. Therefore, a reflective liquid crystal display device made by using this reflective electrode has a bright and high-quality display that does not have wavelength dependence due to a light source and does not deteriorate in color characteristics. It becomes the performance.

Further, the insulating film having the uneven structure may be an organic resin or an inorganic resin having a photosensitivity.
As a result, the desired uneven pattern can be formed by directly exposing and developing the photosensitive resin, so that the steps of coating, forming, developing, and peeling the photoresist required for forming the uneven structure can be performed. It is completely unnecessary. Therefore, the number of processes can be simplified, and the cost of the reflective liquid crystal display device can be reduced.

The method of manufacturing the reflective liquid crystal display device according to the present invention is a method of manufacturing the reflective liquid crystal display device according to the present invention. That is, in the concavo-convex structure, a predetermined pattern is formed by performing a photolithography process on the insulating film, and at this time, patterning is performed while leaving a predetermined film thickness,
The uneven structure is formed on the surface of the insulating film by irregularly forming the thin and thick regions in a plane.

As a result, the plane shape of the concavo-convex structure formed on the insulating film and its arrangement can be built in the insulating film by reflecting the mask pattern, so that the plane shape can be accurately controlled and desired. The uneven shape can be formed with good reproducibility. Furthermore, if the insulating film is etched so as to leave a desired film thickness, the cross-sectional shape of the unevenness can be controlled with good reproducibility, so that a good unevenness structure can be realized. Moreover, these manufacturing processes are only 1PR process +
Since the process can be performed in one etching step, the process can be simplified. In addition, since the metal wiring, electrodes, switching elements, and insulating film located under the uneven insulating film are not exposed to the process atmosphere (etching solution, etching gas, etc.), the metal wiring, insulating film, and switching element are not exposed. It is possible to realize a reflection type liquid crystal display device having good element characteristics without damaging the device.

Further, according to the present invention, the concavo-convex structure formed on the insulating film has a step of forming the insulating film, a photolithography process for forming a concavo-convex resist pattern, and a predetermined portion below the insulating film. Forming a smooth and continuous concavo-convex structure by a step of performing etching so as to leave the remaining film thickness, a step of removing the resist film remaining on the insulating film, and a step of subsequently melting the concavo-convex film by heat treatment. You may.

According to such a manufacturing method, since it is possible to process the concavo-convex pattern without exposing the switching elements, wirings, electrodes and the like located under the insulating film, the switching elements and the like are not damaged by the process. An uneven pattern can be formed. Further, since the uneven insulating film located under the reflective electrode does not require the base convex forming step and the film forming step thereabove unlike the uneven insulating film of the conventional reflective liquid crystal display device, the same film is used. Since the uneven insulating film can be formed in the same step, the number of steps can be simplified.

Further, the concavo-convex structure formed on the insulating film includes a step of forming an organic insulating film or an inorganic insulating film having a photosensitivity as the insulating film, and an exposure step of forming a concavo-convex pattern. A smooth and continuous concavo-convex structure may be manufactured by a developing step of performing etching development so as to leave a predetermined film thickness under the insulating film, and then a melt step of melting the concavo-convex film by heat treatment. .

As a result, the steps of coating, forming, developing and peeling the resist required to form the uneven structure are not necessary at all, and the desired uneven pattern can be obtained by directly exposing and developing the photosensitive resin. It is possible to form the liquid crystal display device, so that the number of processes can be further simplified and the cost of the reflective liquid crystal display device can be reduced.

Further, an organic insulating film or an inorganic insulating film having photosensitivity may be used as an insulating film, and the concavo-convex structure and the contact portion may be simultaneously manufactured in the same developing process for this insulating film. According to such a manufacturing method,
The uneven structure and the contact hole can be formed by a simple method without using a resist process.

At this time, by using a positive type photosensitive material and increasing the exposure amount for forming the contact pattern more than the exposure amount for forming the uneven pattern, the uneven pattern and the contact pattern are simultaneously formed in the same developing step. It may be formed. As a result, the contact formation step can be omitted, and the process can be simplified.

[0036]

1 is a sectional view showing a first embodiment of a reflective liquid crystal display device according to the present invention. Hereinafter, description will be given with reference to this drawing.

The reflective liquid crystal display device according to the present embodiment includes a glass substrate 53 as a transparent first substrate and a glass substrate 5.
3, a transparent electrode 55 provided on the glass substrate 40, a glass substrate 40 as a second substrate, a thin film transistor 44 as a switching element provided on the glass substrate 40, a thin film transistor 44 provided on the thin film transistor 44, and an uneven structure 4 on the surface.
5a is formed on the insulating film 45, and the reflective electrode 48 is provided on the insulating film 45 in a shape reflecting the uneven structure 45a and is connected to the source electrode of the thin film transistor 44.
And the transparent electrode 55 side of the glass substrate 53 and the glass substrate 40.
And a liquid crystal layer 56 sandwiched between the liquid crystal layer 56 and the reflective electrode 48 side. The insulating film 48 protects the thin film transistor 44 after the thin film transistor 44 is formed, and also has irregularities 45a formed by irregularly arranging regions having different film thicknesses.

The thin film transistor 44 is formed by depositing a metal layer 41, an insulating layer 42, a semiconductor layer 43 and the like, and subjecting these films to photolithography and etching, to form a gate electrode, a gate insulating film and a semiconductor film. The reverse stagger structure is composed of a source electrode, a drain electrode, and the like. In addition, the insulating layer 45 used for the organic insulating material or the inorganic insulating material is located on the thin film transistor 44. The insulating film 45 is provided with the uneven structure 45a having a desired shape by irregularly arranging regions having different film thicknesses. The concavo-convex structure 45a includes a convex portion 46 having a large film thickness and a concave portion 47 having a thin film thickness.
Then, the reflective electrode 48 is formed on the insulating film 45. The reflective electrode 48 is electrically connected to the source electrode of the thin film transistor 44 through a contact hole 49 formed in the insulating film 45, and also has a function as a pixel electrode.

An insulating film 45 is formed on the surface of the reflective electrode 48.
The concave-convex structure 45a formed on the surface is reflected, and the concave-convex inclination angle determines the optical characteristics of the reflected light.
Therefore, the inclination angle of the concavo-convex structure 45a is designed so that desired reflection optical characteristics can be obtained. The uneven structure 45
It suffices that a is composed of two or more values having different convex pitches, concave pitches, convex heights, and concave depths.

Next, the operation of the reflective liquid crystal display device of this embodiment will be described.

The reflective liquid crystal display device operates as follows in the white state. Incident light 50 that enters from the outside of the glass substrate 53 passes through the polarizing plate 51, the retardation plate 52, the glass substrate 53, the color filter 54, the transparent electrode 55, and the liquid crystal layer 56, and then the unevenness of the surface of the reflective electrode 48 is generated. The light is reflected according to the directivity reflecting the shape, passes through the liquid crystal layer 56, the transparent electrode 55, the color filter 54, the glass substrate 53, the retardation plate 52, and the polarizing plate 51 again, and is returned to the outside as display light 58. On the other hand, the reflective liquid crystal display device operates as follows in the black state. Incident light 50 incident from the outside of the glass substrate 53 receives the polarizing plate 51, the retardation plate 52,
Glass substrate 53, color filter 54, transparent electrode 55,
Although it passes through the liquid crystal layer 56 and is reflected by the reflective electrode 48, it is not emitted to the outside because it is shielded by the polarizing plate 51.
This enables ON / OFF operation of light.

FIG. 2 is a sectional view showing a first embodiment of a method of manufacturing a reflective liquid crystal display device according to the present invention. Less than,
A description will be given based on this drawing.

First, the thin film transistor 44 is formed on the glass substrate 40 (FIG. 2A). Subsequently, an acrylic resin film 60 as an organic insulating film is applied and formed, and a photoresist (not shown) is applied and exposed thereon to form a concavo-convex pattern, and the acrylic resin film 60 is etched.
An uneven pattern 61 is formed on the substrate, and then the photoresist is peeled off (FIGS. 2B and 2C). Subsequently, a photoresist (not shown) is applied again, exposed and developed, the acrylic resin film 60 is etched, the photoresist is peeled off, and a contact hole 62 is formed in the acrylic resin film 60 (FIG. 2 [d]). . Finally, an aluminum film is formed, a photoresist is applied, exposed and developed, the aluminum film is etched, and the photoresist is peeled off to form the reflective electrode 63 (FIG. 2E).

The acrylic resin film 6 shown in FIGS. 2B and 2C.
When the unevenness is formed to 0, the convex portion 46 composed of a thick film region is formed.
And a recess 47 formed of a thin region. By leaving the acrylic resin film 60 in the thin film region as well, the switching element 44 and the like are always covered with the acrylic resin film 60. At this time, the acrylic resin film 6 under the resist pattern
By etching 0 to a desired depth and leaving a thin acrylic resin film 60, an uneven structure / interlayer insulating film can be formed by the same material and the same process. Since the height 64 of the convex portion 46 and the film thickness 65 of the concave portion 47 can be changed by controlling the etching amount, the uneven shape or the film thickness of the concave portion can be freely controlled.

In this embodiment, an acrylic resin is used for the insulating film, but a thickness that can simultaneously satisfy the requirements for the height of the unevenness required for the optical characteristics of the reflector and the film thickness required for the interlayer film. Any insulating film can be used as long as it can form a thickness, and other organic resin such as polyimide resin may be used. Alternatively, an inorganic insulating film such as a silicon nitride film or a silicon oxide film may be used.

Considering the directivity of the reflected light, the uneven structure at this time preferably has a height in the range of 0.2 to 4 μm and a pitch in the range of 1 to 30 μm. Furthermore, the convex portions or the concave portions are irregularly arranged on a plane, and the planar shape of the convex portions may be an island pattern or a linear pattern, and the planar shape of the concave portions may be a hole pattern or a groove pattern. Basically, it suffices that the patterns of these convex portions or concave portions are arranged irregularly. Since this can suppress the interference of the reflected light at the reflective electrode, it is possible to obtain a good reflection that is bright and does not depend on wavelength. The characteristics can be realized.

3 and 4 are cross-sectional views showing a second embodiment of the method of manufacturing the reflection type liquid crystal display device according to the present invention. Hereinafter, description will be given with reference to this drawing.

In this embodiment, the insulating film under the reflective electrode is composed of the uneven film and the interlayer film, which are formed in separate steps. First, the lower layer film 70 is formed by coating (see FIG.
[B]), and subsequently an upper layer film 71 is formed by coating (FIG. 3).
[C]). Subsequently, a concavo-convex pattern is formed on the upper layer film 71 by patterning a photoresist to form the upper layer film 71 as the concavo-convex film 72 and the lower layer film 70 as the interlayer film 73 (FIG. 4 [d]). The other steps are the same as those in the embodiment of FIG.

The lower layer film 70 and the upper layer film 71 may be made of different materials. For example, an organic resin such as acrylic resin, which is a material having a good controllability of the uneven shape, is used for the upper layer film 71, and a silicon nitride film which is a material excellent in electrical insulation performance, passivation property, process resistance, etc. The inorganic insulating film may be used as the lower layer film 70. Further, the films used as the uneven film 72 and the interlayer film 73 are not limited to the insulating materials described above as long as they satisfy the required performances, and various combinations of materials can be applied.

Although the case where the thin film transistor having the inverted stagger structure is applied as the switching element has been described in the present embodiment, the invention is not limited to this, and a switching element such as a thin film transistor having a forward stagger structure or an MIM diode may be used. Further, although glass substrates are used for the lower side substrate and the opposite side substrate, the present invention is not limited to this,
Other substrates such as a plastic substrate, a ceramic substrate, a semiconductor substrate and the like may be used, and a combination of these different substrates may be used.

FIG. 5 is a sectional view showing a third embodiment of a method of manufacturing a reflection type liquid crystal display device according to the present invention. Less than,
A description will be given based on this drawing.

In this embodiment, the projections are formed and then heat-treated to change the uneven shape, so that a smooth uneven shape is used for the uneven structure under the reflective electrode. Up to the process of FIG. 5A, the same process as the thin film transistor manufacturing process shown in FIG. 2 is performed. Subsequently, an insulating film 74 having a concavo-convex structure is formed (FIG. 5B), and the insulating film 7 is formed.
By melting 4 by heat treatment, it is converted into an insulating film 74 ′ having a smooth uneven structure (FIG. 5C). By changing the bake temperature and the bake time at this time, the melting state of the convex portions of the insulating film 74 changes, so that the uneven shape finally formed can also be controlled by this melting condition. In the present embodiment, the concavo-convex structure is made smooth and continuous by heat treatment, but the present invention is not limited to this. For example, by exposing the material used for the concavo-convex structure to a solution having a melting property or a swelling property. It is also possible to convert the uneven surface into a smooth shape.

After that, a contact hole 62 is formed (FIG. 5D) and a reflective electrode 63 is formed (FIG. 5D).
[E]), the manufacture of the reflective TFT substrate is completed. As a result, the uneven shape formed on the surface of the reflective electrode 63 becomes smoother, and the reflective optical characteristics are improved.
The reflective liquid crystal display device using the FT substrate can realize bright display. In the present embodiment, the melting method by heat treatment is used to obtain a smooth uneven surface, but the present invention is not limited to this, and similar effects can be obtained by melting with a chemical as another method.

By the way, in the embodiment shown in FIGS. 2 and 5, the insulating film located under the reflective electrode is formed in the same step by using the same material. That is, a single-layer film is formed as an insulating film under the reflective electrode, and the single-layer film is patterned by a photolithography process and the insulating film is etched to form a thick film region in the insulating film formation region. Thin areas are selectively formed and used for the relief structure.
Therefore, since the concavo-convex structure can be formed by a single layer film, it is most suitable for shortening the manufacturing process, and thus the reflective liquid crystal display device can be provided at low cost.

In each of the above-described embodiments, the uneven structure is formed by selectively forming the thick and thin regions of the insulating film on the plane by the photolithography process, but the present invention is not limited to this. As another method, the film thickness of the printing resin by screen printing may be controlled, or the surface of the insulating film may be roughened by a chemical solution to generate a difference in film thickness and form a step.

In the embodiment of FIGS. 2 and 5, the insulating film located under the reflective plate is formed by the same process and the same material. However, the present invention is not limited to this, and FIGS.
As shown in the above embodiment, the base film and the upper convex film may be formed in different steps, or the concavo-convex structure may be formed using films of different materials. Even if this is used for the uneven structure of the insulating film to form a reflective electrode, a reflective electrode having desired optical characteristics can be provided. However, in this case, although there is a drawback that the number of steps is increased, there is an advantage that the thickness of the base film can be surely controlled.

FIG. 6 is a sectional view showing a second embodiment of the reflection type liquid crystal display device according to the present invention. Hereinafter, description will be given with reference to this drawing.

In the present embodiment, the insulating film 45 formed under the reflective electrode 48 includes the thin film transistor 44, the wiring 80,
It is formed so as to cover the electrodes 81 and the like. The reflective electrode 48 serving as a reflective plate and a pixel electrode electrically connected to the thin film transistor 44 by the contact portion 49 has a structure in which an interlayer is separated via the insulating film 45. That is, the insulating film 45 has a function as a protective film. The insulating film 45 in this embodiment is used as a passivation film of the thin film transistor 44 by directly contacting the thin film transistor 44. A silicon nitride film (SiN) or a silicon oxide film (SiO) conventionally used as a protective film for the thin film transistor 44 may be inserted between the insulating film 45 and the thin film transistor 44.

FIG. 7 is a sectional view showing a third embodiment of the reflection type liquid crystal display device according to the present invention. Hereinafter, description will be given with reference to this drawing.

In the present embodiment, the insulating film 101 formed under the reflective electrode 48 may be an organic resin or an inorganic resin as long as it has an insulating property, and further has transparency, coloring property, and light absorbing property. Etc. may be included. In particular, the insulating film 10
When 1 has a light absorbing property, the light 100 incident between the adjacent reflective electrodes 48 can be completely absorbed by the insulating film 101, so that the light incident on the thin film transistor 44 can be prevented. As a result, the light off-leakage characteristic of the thin film transistor 44 can be prevented, so that a reflection type liquid crystal display device having good switching element characteristics can be realized.

Insulating film 101 having a light absorbing property at this time
Is not particularly limited to this position, because the same effect can be realized if it is arranged so as to prevent the thin film transistor 44 from being irradiated with light. Also,
The insulating film 101 also serves as an insulating film having a smooth concave-convex structure formed under the reflective electrode 48, so that the process can be simplified. As materials for the insulating film 101, trade names “black resist” and “CFP” manufactured by Tokyo Ohka Kogyo Co., Ltd.
By using “R”, “BK-748S”, “BK-430S” or the like, it is possible to form a good light absorbing layer and a good uneven structure. The same effect can be obtained with other black resin materials. Further, the light absorbing layer may be a light reflecting film as well as a light absorbing film, and may be a metal material, an insulating material that does not transmit light, or an inorganic compound film.

FIG. 8 is a plan view of a mask pattern showing a fourth embodiment of the reflective liquid crystal display device according to the present invention.
Hereinafter, description will be given with reference to this drawing.

As shown in each of the above-mentioned embodiments, the cross-sectional shape of the uneven structure of the insulating film located under the reflective electrode is such that a thick film region and a thin film region are selectively formed in a plane in the insulating film formation region. It is formed by doing. This uneven structure is reflected in the uneven structure on the surface of the reflective electrode. The concavo-convex structure of the insulating film is formed using a pattern arranged irregularly on the mask. FIG. 8 shows a mask pattern corresponding to one pixel used for forming the unevenness. Note that reference numerals 110 and 112
Is a light transmitting region.

In this embodiment, the convex patterns are arranged irregularly, and the size of the convex patterns is 2 to 20.
The pitch is about 2 μm and the pitch is about 2 to 40 μm. Figure 8
In FIG. 8A, the island-shaped convex patterns 111 are irregularly arranged, and in FIG. 8B, the linear convex patterns 113 are irregularly arranged. It is possible to form a reflective electrode having good reflective optical characteristics in any of the concavo-convex structures formed using either mask. Therefore, the reflective liquid crystal display device manufactured using this can obtain good display characteristics.

In the present embodiment, the island-shaped pattern having the same size or the linear pattern having the same line width is used, but the present invention is not limited to this. For example, in the island pattern, different sizes may be used, and each pattern may be a polygon pattern (triangle, pentagon, hexagon, heptagon, etc.) other than a square,
A circular shape, an elliptical shape, or the like may be used, and the same effect can be obtained even if patterns of various shapes are mixed. Further, the linear pattern may be a line pattern of various widths or a curved pattern, and these patterns may be non-uniform. Also,
It may be a mixture of island patterns and line patterns.

FIG. 9 is a plan view of a mask pattern showing a fifth embodiment of the reflective liquid crystal display device according to the present invention.
Hereinafter, description will be given with reference to this drawing.

The mask pattern of the present embodiment is the mask pattern of FIG. 8 with the irregularities reversed. That is, the hole-shaped concave pattern 115 or the groove-shaped concave pattern 1
17 are arranged irregularly. Even with such a mask pattern, a high-brightness reflective electrode could be obtained.
The size of the concave pattern of the mask pattern used at this time is about 2 to 20 μm in outer shape and about 2 to 40 μm in pitch. Incidentally. Reference numerals 114 and 116 are light shielding regions.

Also in the case of this embodiment, the hole-shaped pattern of the same size or the groove-shaped pattern of the same width is used.
It is not limited to this. For example, the hole-shaped patterns may have different sizes, and the individual patterns may be polygonal patterns (triangular, pentagonal, hexagonal, heptagonal, etc.) other than square, circular, elliptical, etc. Similar effects can be obtained even when patterns of various shapes are mixed. Furthermore,
The groove pattern may be a line pattern of various widths or a curved pattern, and these patterns may be non-uniform.
Further, the hole pattern and the groove pattern may be mixed.

FIG. 10 is an explanatory view showing a sixth embodiment of the reflection type liquid crystal display device according to the present invention. Hereinafter, description will be given with reference to this drawing.

The concavo-convex pattern in this embodiment may be irregular in the range of one pixel or more in the reflective liquid crystal display device, and may be irregular in the region of 3 pixels or 4 pixels such as RGB or RGGB. In addition, an irregular concavo-convex pattern may be formed in a region having a larger number of pixels, and this may be repeated to form concavo-convex in the reflective electrode region on the entire surface of the panel display portion. In this case, it is possible to obtain a bright reflector similar to the case where the entire reflector panel is formed in a completely irregular pattern.

FIG. 10A shows an example in which the entire display area is formed by one irregular arrangement pattern, and FIG. 10B shows an example in which the entire display area is formed by repeating the irregular arrangement pattern in units of one pixel. 10 [c] shows an example in which the entire display area is formed by repeating the irregularly arranged pattern in units of 1 pixel or more. Desirably, an irregular region is formed in units of one pixel or more, and this irregular region pattern is repeated to form irregularities in the entire region of the reflective electrode. Although the island-shaped pattern is shown in this embodiment, the present invention is not limited to this.
As shown in FIGS. 8 and 9, the same effect can be realized in any of a linear pattern, a hole pattern, a groove pattern, and the like.

11 and 12 are sectional views showing a fourth embodiment of the method of manufacturing the reflection type liquid crystal display device according to the present invention. Hereinafter, description will be given with reference to this drawing.

In this embodiment, the insulating film used under the reflective electrode is made of a material having photosensitivity, as shown in FIG.
2 is the same as the embodiment of FIG. 2 except for the above. FIG. 11 shows an insulating film 133 using a photoresist.
When a concave-convex pattern is formed on the surface (comparative example), FIG.
Shows the case of the present embodiment. In the case of the present embodiment, both the upper layer concavities and convexities 130 and the lower layer film 131 of the insulating film located under the reflective electrode are made of the photosensitive resin 132. In this case, the photosensitive resin 132 is applied and formed, and thereafter, the upper layer unevenness 130 and the lower layer film 131 are exposed and developed.
Will be formed simultaneously.

In this embodiment, since the photosensitive resin is used, the step of forming the mask pattern 135 by the photoresist layer 134 is shown in FIG. 11 [b1], [c1], [d1].
Does not need That is, since the pattern processing can be performed by directly exposing and developing the photosensitive resin, the resist coating and stripping steps can be simplified, and the number of manufacturing steps shown in the comparative example of FIG. 11 can be shortened. The reflective liquid crystal display device can be provided at low cost.

The photosensitive resin in this embodiment may be an organic resin such as an acrylic resin or a polyimide resin, or an inorganic resin. Also, as mentioned above,
A photosensitive resin of a different material may be used for the upper and lower layers of the insulating film below the reflective electrode, and further, only the upper and lower layers of the insulating film or the lower layer may be made of a photosensitive resin. Further, the lower side substrate or the opposite side substrate used in this embodiment does not have to be a glass substrate, and a substrate made of other material may be used as described above. Further, the photosensitive resin in the present embodiment does not need to be transparent, and may be a black one capable of absorbing light. In particular, a transparent photosensitive material may be used for the semi-transmissive type and a black photosensitive material may be used for the reflective type (shown in the following seventh embodiment).

FIG. 13 is a sectional view showing a seventh embodiment of the reflection type liquid crystal display device according to the present invention. Hereinafter, description will be given with reference to this drawing.

FIG. 13A shows a reflection type liquid crystal display device, and the insulating film 101a is made of a black photosensitive material. FIG.
[B] is a reflective liquid crystal display device (transflective liquid crystal display device) that also serves as a transmissive device, and the insulating film 101b is made of a transparent photosensitive material. By thinning the reflective electrode 48 'in FIG. 13B, the light of the backlight 140 can be transmitted. Note that the semi-transmissive liquid crystal display device is not limited to this structure and may have another structure. For example, by partially opening a reflective electrode in a pixel, a backlight light is generated in that region. A method of transmitting 141 may be used.

14 and 15 are sectional views showing a fifth embodiment of the method of manufacturing the reflection type liquid crystal display device according to the present invention. Hereinafter, description will be given with reference to this drawing.

In this embodiment, an inverted staggered thin film transistor is used as a switching element. In the manufacturing process of the TFT substrate in the present embodiment, [a] electrode material is formed, [b] gate electrode 150 is formed, [c] gate insulating film 151, semiconductor layer 152, doping layer 153 is formed, and [d] electrode is formed. Material, [e] island 154 formation, [f] source electrode 155 and drain electrode 156 formation, [g] insulating film 157 formation, [h] unevenness 158 formation on the insulating film upper layer portion, [i] ] Contact hole 159
And the formation of the [j] reflective electrode 160.

Further, in the step [h], (1) resist 163 is formed on the insulating film 157, and (2) uneven pattern 164.
Formation (3) formation of irregularities 158 on the upper layer of the insulating film 157,
(4) Each step such as resist stripping. At this time, the height X of the unevenness and the thickness Y of the lower layer are the same as those of the insulating film 1 in the step (3).
57 It can be controlled by the etching amount of the upper layer portion. Therefore, the unevenness height X may be determined by the unevenness height required for the desired optical characteristics of the reflector, and the thickness Y of the lower layer film may be determined by the coverage of the underlying switching element, the wiring, etc., and the insulating property. Good.

Although the case where the inverted staggered thin film transistor is applied as the switching element has been described in the present embodiment, the invention is not limited to this, and a switching element such as a forward staggered thin film transistor or an MIM diode may be used. Further, the inverted staggered thin film transistor is not limited to the structure shown in this embodiment, and may have a structure other than this. Further, although glass substrates are used for the lower side substrate and the counter side substrate, the present invention is not limited to this, and other substrates such as a plastic substrate, a ceramics substrate, and a semiconductor substrate may be used. Furthermore, in the present embodiment, the insulating film having the uneven structure on the surface in the step (3) has the single film structure in the same step, but the invention is not limited to this.

16 and 17 are sectional views showing a sixth embodiment of the method of manufacturing a reflection type liquid crystal display device according to the present invention. Hereinafter, description will be given with reference to this drawing.

The manufacturing process other than the formation of the insulating film having the uneven structure on the surface is the same as the manufacturing process shown in FIGS. That is, the uneven insulating film of the present embodiment is subjected to the same steps as FIGS. 14A to 14F until the formation of the switching element, and thereafter, (1) the insulating layer 161 for the interlayer film is formed, and (2) the unevenness. Forming an insulating layer 162 for formation, (3)
Formation of the uneven pattern 164 by the resist 163,
(4) Concavo-convex structure 165 is formed, and (5) Resist peeling is performed.

As a result, the concavo-convex layer 166 of the insulating layer and the lower layer film 167 formed under the reflective electrode can be formed in separate steps. Therefore, an acrylic resin whose concavo-convex shape is easy to control is used for the concavo-convex layer of the upper layer portion, and a silicon nitride film having excellent passivation performance or electrical insulation with a base is used for the lower layer portion, which has better optical characteristics, and A switching element substrate having excellent element characteristics can be provided. As a result, it is possible to realize a reflective liquid crystal display device with high performance and high quality display.

The concavo-convex layer and the lower layer film used in this embodiment are not limited to these, and other organic insulating films such as polyimide and inorganic insulating films such as silicon oxide film may be used. Further, the materials of the upper layer and the lower layer may be the same.

18 and 19 are sectional views showing a seventh embodiment of the method of manufacturing the reflection type liquid crystal display device according to the present invention. Hereinafter, description will be given with reference to this drawing.

The present embodiment differs from the embodiments of FIGS. 14 and 15 in that the insulating film 157 used under the reflective electrode 160 is made of a material having photosensitivity.
Other than that is the same as the embodiment of FIGS. 14 and 15.

According to this embodiment, the photosensitive resin is directly
Since patterning can be performed by exposing and developing, the resist coating and stripping steps can be simplified, and FIG.
Also, the number of manufacturing steps can be significantly shortened compared to the number of manufacturing steps shown in the embodiment of FIG. 15, and as a result, a reflective liquid crystal display device can be provided at low cost.

20 and 21 are sectional views showing an eighth embodiment of the method of manufacturing the reflection type liquid crystal display device according to the present invention. Hereinafter, description will be given with reference to this drawing.

The present embodiment differs from the embodiments of FIGS. 18 and 19 in that the step of forming a contact hole in the insulating film used under the reflective electrode is performed at the same time as the step of forming irregularities.
Other than that is the same as the embodiment of FIGS. 18 and 19.
In the manufacturing process of the TFT substrate in the present embodiment, [a] electrode material formation, [b] gate electrode formation, [c] gate insulating film, semiconductor layer, doping layer formation, [d] electrode material formation, [E] Island formation, [f] Source electrode and drain electrode formation. After that, [g] formation of the photosensitive insulating layer 170, [h] exposure to the photosensitive insulating layer (contact region 171 and uneven region 172), and [i] simultaneous contact and unevenness to the photosensitive insulating layer in the developing step. Forming and melting of uneven surface by heat treatment, [j] reflective electrode 1
The formation of 73 continues.

In the step [h] of this embodiment, each pattern is simultaneously exposed in the contact formation region and the concavo-convex formation region in the same exposure process. After that, in the development etching step, processing is performed such that the unevenness forming portion has a depth X and the contact forming portion has a depth Z.

In this case, in the step [h], the amount of exposure energy in the exposure process of the uneven pattern portion 175 and the contact portion 174 is set so that the contact portion 174 is larger than the uneven pattern portion 175, and the photosensitive insulating layer 170 is further added. The amount of exposure energy may be adjusted so that the lower layer has a desired film thickness Y. As a method of adjusting this exposure amount, two types of masks for forming a concavo-convex pattern and a mask for forming a contact pattern may be used, and double exposure may be performed so that the respective exposure amounts may be different, or one sheet may be used. It is also possible to use a mask in which a mask material is adjusted so that the unevenness pattern portion and the contact pattern portion in the mask have different exposure light transmittances. In this way, if the exposure energy in the exposure process is made different depending on the pattern portion, it is possible to realize pattern formation having different etching amounts in the same substrate under the same development conditions. In this embodiment, the uneven surface is converted into a smooth shape by applying heat treatment to the insulating film.

According to this embodiment, the photosensitive resin is directly
Since the patterning can be performed by exposing and developing, and the concavo-convex forming step and the contact forming step can be realized by the same exposing and developing etching step, the number of manufacturing steps shown in the embodiment of FIGS. 18 and 19 is further increased. A reflective liquid crystal display device can be provided at a low cost, which can be shortened.

Further, in this embodiment, the photosensitive material is used for forming the uneven insulating layer, but if a resist process is used, a similar structure can be obtained by using a non-photosensitive material. However, although the number of steps is increased because a resist process is required, the number of steps can be shortened as compared with the conventional manufacturing process of a reflective liquid crystal display device.

[0095]

EXAMPLES Example 1 FIGS. 22 and 23 show the manufacturing process of the reflective liquid crystal display device used in this example. A forward staggered thin film transistor is used as the switching element.

In the manufacture, the following steps are carried out on a glass substrate. [A] ITO is formed to a thickness of 50 nm by a sputtering method. [B] Formation of source 200 and drain electrode 201.
(1PR) [c] Doping layer 202 is 100 nm, semiconductor layer 203 is 100 nm, and gate insulating film 204 is 40 nm.
Deposition by 0 nm plasma CVD. [D] Cr layer 205
Formed by sputtering to a thickness of 50 nm. [E] Formation of island 206 of gate electrode and TFT element part. (2P
Rth) [f] Formation of organic insulating film 207 (3 μm).
[G] Formation of the concavo-convex pattern 208 on the upper layer of the organic insulating film (3PR) [h] Formation of the contact 209 (4PR)
[I] 300n of aluminum by sputtering
m formation. [J] Formation of reflective pixel electrode plate 210. (5P
R)

In the step [c], a laminated film of a silicon oxide film and a silicon nitride film is used for the gate insulating film, an amorphous silicon film is used for the semiconductor layer, and an n-type amorphous silicon film is used for the doping layer. These plasma CVD conditions were set as shown below. In the case of a silicon oxide film, silane and oxygen gas are used as the reaction gas, the gas flow rate ratio (silane / oxygen) is set to about 0.1 to 0.5, the film formation temperature is 200 to 300 ° C., the pressure is 133 Pa, and the plasma power is It was set to 200W. In the case of a silicon nitride film, silane and ammonia gas are used as reaction gases, the gas flow rate ratio (silane / ammonia) is set to 0.1 to 0.8, the film formation temperature is 250 ° C., the pressure is 133 Pa, and the plasma power is 20.
It was set to 0W. In the case of an amorphous silicon film, silane and hydrogen gas are used as the reaction gas, the gas flow rate ratio (silane / hydrogen) is set to 0.25 to 2, and the film formation temperature is 200 to 250.
C., pressure 133 Pa, and plasma power 50 W. n
In the case of the typed amorphous silicon film, silane and phosphine were used as the reaction gas, the gas flow rate ratio (silane / phosphine) was set to 1 to 2, the film formation temperature was 200 to 250 ° C., the pressure was 133 Pa, and the plasma power was 50 W.

In the island formation of the TFT element portion in the above step [e], wet etching was adopted for the Cr layer and dry etching was adopted for the silicon oxide film, the silicon nitride film and the amorphous silicon layer. For etching the Cr layer, a mixed aqueous solution of perhydrochloric acid and ceric ammonium nitrate was used. Further, in etching the silicon nitride film and the silicon oxide film, fluorine tetrachloride and oxygen gas are used as an etching gas, and a reaction pressure of 0.
665 to 39.9 Pa, plasma power 100 to 300
W. Further, chlorine and hydrogen gas are used for etching the amorphous silicon layer, and a reaction pressure of 0.665 to
The plasma power was 39.9 Pa and the plasma power was 50 to 200 W.
In addition, in the photolithography process, a usual resist process was used.

In this embodiment, ITO is used for the source and drain electrodes and Cr metal is used for the gate electrode, but the electrode materials are not limited to these. Other electrode materials include Ti, W, Mo, Ta, Cu, Al, Ag, and IT.
A single layer film of O, ZnO, SnO or the like, or a laminated film formed by combining these electrodes may be adopted.

In this embodiment, the unevenness formed under the reflective electrode is formed in the above [f] [g] steps. That is,
The resist film 2 is formed on the insulating film formed in the above step [f].
Then, a concavo-convex resist pattern is formed by exposure and development processes, the insulating film is etched to a depth of 1 μm, and the resist is peeled off to form a concavo-convex structure in the upper layer portion of the insulating layer.

A polyimide film (trade name “RN-81” manufactured by Nissan Chemical Industries, Ltd. is used as the organic insulating film in the step [f].
2 ") was used. In the case of the polyimide, the coating conditions are 1200 rpm for spin rotation, 90 ° C. for calcination temperature,
The calcination time was 10 minutes, the calcination temperature was 250 ° C., and the calcination time was 1 hour. On the other hand, in the case of the resist used for pattern formation, the spin rotation speed was 1000 rpm, the calcination temperature was 90 ° C., the calcination time was 5 minutes, after which the pattern was formed by exposure and development, and post baking was performed at 90 ° C. for 30 minutes. The dry etching conditions for the polyimide film performed using the resist pattern as a mask layer were to use fluorine tetrachloride and oxygen gas as etching gas, and set the gas flow rate ratio (fluorine tetrachloride / oxygen) to 0.5 to 1.5. Reaction pressure of 0.665 to 39.9 Pa, plasma power of 10
It was set to 0 to 300 W. In addition, all the photolithography processes used the normal resist process.

Further, in this embodiment, the reflector and the TF are used.
Although the insulating layer formed in the same step is used as the uneven insulating layer located between the T elements, as another example, the first organic resin is formed after the formation of the TFT of [e] is completed ( Two
.mu.m), a second organic resin is formed (1 .mu.m), and a resist process and an etching process are performed to form a concavo-convex structure on the second organic resin, and a desired concavo-convex insulating layer can be formed. The basic manufacturing process may be the same as the steps described in the above embodiment.

Although the same organic resin material is used for the first insulating film and the second insulating film, the uneven insulating layer can be similarly formed by using different materials. First insulating film and second
The insulating film can be realized by using a combination of an inorganic resin and an organic resin such as an acrylic resin and a polyimide resin, a silicon nitride film and an acrylic resin, a silicon oxide film and a polyimide resin, or the reverse combination.

In this embodiment, thereafter, the reflection efficiency is high,
An aluminum metal having good compatibility with the TFT process was formed, and this was patterned to form a pixel electrode / reflector. At this time, the aluminum was wet-etched, and the etching solution used was a mixed solution of phosphoric acid, acetic acid, and nitric acid heated to 60 ° C.

In this embodiment, in the unevenness forming step, the patterning step for forming the unevenness is performed with the insulating layer covering the switching element, so that the switching element is directly exposed to the etching process. Never. Therefore, problems such as deterioration or instability of switching element characteristics due to process damage are not caused, which is a great achievement in improving the performance of the reflective liquid crystal display.

The maximum height of the unevenness was set to about 1 μm, and the planar shape of the unevenness was set to a random shape. Then, the TFT substrate and the counter substrate having a transparent electrode made of ITO were superposed so that their film surfaces face each other. It should be noted that the TFT substrate and the counter substrate are subjected to orientation treatment, and both substrates are subjected to spacers such as plastic particles,
By applying an epoxy-based adhesive around the panel,
Pasted together. After that, a liquid crystal was injected to form a liquid crystal layer to manufacture a reflective liquid crystal display device.

FIG. 24 is a sectional view of the reflection type liquid crystal display device obtained in this example. In the reference numerals in FIG. 24, 212 is a counter substrate, 213 is an upper glass substrate, 21
4 is a color filter, 215 is ITO (indium tin oxide), 216 is incident light, 217 is reflected light,
218 is a liquid crystal, 219 is a reflector, 220 is an organic insulating film,
221 is a glass substrate.

The reflective pixel electrode of this reflective liquid crystal display device is uniform and has a good light-scattering reflective property. Therefore, a monochrome reflective panel having a whiter display brighter than newspaper can be realized at low cost. Further, when the RGB color filter is installed on the counter substrate side, a bright color reflective panel is realized at low cost.

The height of the unevenness of this embodiment is not limited to the above. Since the height of the unevenness can be changed in a wide range, by using this uneven structure, it is possible to provide a reflective liquid crystal display device in which the directivity of the performance of the reflector is largely changed.

(Embodiment 2) The manufacturing process of the reflection type liquid crystal display device used in this embodiment is shown in FIGS. An inverse staggered thin film transistor is used as a switching element in the reflective liquid crystal display device.

In the manufacture, the following steps are performed on the glass substrate 230. [A] Cr 50n by sputtering method
m formation. [B] Formation of gate electrode 231. (1PR)
[C] The gate insulating film 232 is 400 nm, the semiconductor layer 23
3 and the doping layer 234 are formed by 100 nm plasma CVD. [D] Island formation 235 (2
PR eyes) [e] Cr and ITO layers are formed to a thickness of 50 nm by sputtering. [F] Formation of source electrode 236 and drain electrode 237. (3rd PR) [g] Formation of organic insulating film 238 (3 μm). [H] Forming the concavo-convex pattern 239 on the upper layer of the organic insulating film (4PR) [i] Forming the contact 241 (5PR) [j] Forming aluminum 242 to a thickness of 300 nm by a sputtering method. [K] Formation of reflective pixel electrode plate 243. (6th PR) [l] Gate line terminal out (7th PR)

In this embodiment, the unevenness 240 formed under the reflection plate is formed by the above [g] step. The forming method at this time was the same as that of the first embodiment. In this embodiment, the number of steps is increased as compared with the first embodiment because the reverse stagger structure is adopted as the transistor structure.

The aperture ratio of the reflective pixel electrode plate in this example was 86%. Then, the TFT substrate and I
A counter substrate having a transparent electrode made of TO was superposed so that the respective film surfaces face each other. The TFT substrate and the counter substrate were subjected to orientation treatment, and the two substrates were bonded together by applying an epoxy adhesive to the peripheral portion of the panel via a spacer such as plastic particles.
After that, a GH type liquid crystal was injected to form a liquid crystal layer, thereby manufacturing a reflection type liquid crystal display device.

FIG. 27 is a sectional structural view of the reflection type liquid crystal display device manufactured in this example. The reference numeral in FIG. 27 is
Reference numeral 15 is incident light, 16 is reflected light, 239 is a resist uneven pattern, 241 is a contact, 243 is a reflection plate, and 250.
Is a counter substrate, 251 is a glass substrate, 252 is a color filter, 253 is a transparent electrode, and 254 is a guest-host liquid crystal.

Also in the case of the reflection type liquid crystal display device of the present embodiment, similar to the case of the first embodiment, process damage is not given to the switching element, whereby good element characteristics can be obtained and desired. It was possible to obtain the uneven reflector structure. As a result, the color reflective panel manufactured in this example had a bright, high-quality display.

(Embodiment 3) In this embodiment, the uneven surface located under the reflective electrode has a smooth uneven shape. 28 and 29 are cross-sectional structural views of the reflective liquid crystal display device manufactured in this example.

This example is different from Example 1 except that a process for converting the unevenness under the reflective electrode into a smooth shape was added.
Alternatively, it is exactly the same as in the second embodiment. The difference lies in Example 1.
In step [i], in Example 2, only the step of applying heat treatment is added after the uneven pattern formation in step [h]. Therefore, FIG. 28 is exactly the same as FIG.

In this example, as the heat treatment step after the formation of the concavities and convexities, the treatment was carried out at 260 ° C. for 1 hour in an oven in a nitrogen atmosphere. As a result, the inclination angle of the unevenness before the heat treatment was about 60 to 80 degrees, but was changed to about 10 to 40 degrees after the heat treatment. That is, the obtained concavo-convex shape was converted from a rectangular shape to a sine curve-shaped smooth concavo-convex surface 261. In the case of the reflective liquid crystal display device in this example, the average value of the uneven inclination angle of the uneven surface was set to about 8 degrees. Further, the uneven inclination angle can be controlled by changing the baking temperature in the heat treatment step.

Further, in this embodiment, the height of the unevenness is set to 1 μm as in the first and second embodiments. However, by further increasing the height of the unevenness, the optical properties of the obtained reflector can be very strong. In this case, by applying the invention to a reflective liquid crystal display device having a particularly large screen size, since the visual field dependency of the panel display characteristics on the brightness is small, a reflective liquid crystal display device that is easy to see can be obtained.

Further, by reducing the height of the irregularities, it is possible to obtain the optical characteristics of the reflecting plate having a strong directivity. In this case, a brighter display characteristic can be realized by applying it to a reflective liquid crystal display device for a portable information device having a relatively small screen size. Thus, the uneven surface structure can be freely controlled according to the intended use or the panel display area.

Further, the insulating layer in the present embodiment functions as a protective film for the switching element by being located between the reflecting plate located above it and the switching element located below it.

(Embodiment 4) In this embodiment, the insulating layer located under the reflection plate is composed of an organic insulating film having photosensitivity. 30 and 31 are sectional structural views of the reflective liquid crystal display device manufactured in this example.

The manufacturing process of the reflective liquid crystal display device in this embodiment is the same as that in the first embodiment except that a photosensitive resin (photosensitive acrylic resin in this embodiment) is used for the insulating layer under the reflection plate. It can be made exactly the same as the second embodiment. The difference is that the photosensitive film 27 is formed on the insulating layer formed in the step (f) in Example 1 and the step (g) in Example 2.
This is where 0 is used.

By adding the step of forming the photosensitive film, the unevenness is formed by the step of forming the photosensitive film, the step of directly exposing the photosensitive film,
An etching development process and a melt process by heat treatment are performed.
Therefore, as compared with the concavo-convex forming process performed in Examples 1, 2, and 3, the resist coating process, the resist developing process, and the resist peeling process are not necessary, so that the process can be simplified.

In this embodiment, a photosensitive acrylic resin is used as the photosensitive material, but the photosensitive material is not limited to this. Similar effects could be realized with other photosensitive materials such as a photosensitive organic resin and a photosensitive inorganic film. As the photosensitive material, the trade name “OFP” manufactured by Tokyo Ohka Kogyo Co., Ltd.
R800 ", trade name" LC100 "manufactured by Shipley Co., Ltd., trade name" Optomer series "manufactured by Nippon Synthetic Rubber Co., Ltd., trade name" photosensitive polyimide "manufactured by Nissan Chemical Industries, Ltd. An uneven insulating layer was obtained.

Example 5 FIGS. 32 and 33 show the manufacturing process of the reflective liquid crystal display device used in this example. Inverter staggered thin film transistors are used for the switching elements.

In manufacturing, the following steps are performed on the glass substrate 230. [A] Cr of 50 nm by sputtering method
Formation. [B] Formation of gate electrode 231. (1PR)
[C] The gate insulating film 232 is 400 nm, the semiconductor layer 23
3 and a doping layer 234 of 100 nm each are formed by plasma CVD. [D] Island formation 235
(2nd PR) [e] Cr and ITO layers were formed to 50 nm by sputtering. [F] Source electrode 23
7. Drain electrode 236, formation of concavo-convex electrode 13
0. (3rd PR) [g] Photosensitive acrylic resin 270 (3)
μm) formation. [H] Concavo-convex pattern and contact pattern exposure (4PR) on photosensitive acrylic resin [i] Concavo-convex 239 and contact 241 by development etching process
Simultaneous formation of [j] Aluminum 242 with a thickness of 300 nm by a sputtering method. [K] Reflective pixel electrode plate 243
Formation. (5PR) [l] Gate line terminal (6PR)
Eye)

After that, a reflection type liquid crystal display device was manufactured by stacking opposite substrates. The obtained reflective liquid crystal display device was capable of realizing bright high-quality color display.

In this example, the same conditions as in the manufacturing process of Example 3 were used except that the unevenness and the simultaneous formation of contacts in the process (h) were performed. In this embodiment, the insulating film having a film thickness of 3 μm was completely removed in the contact region and the uneven region was removed so that the underlying film 2 μm remained in the same developing step.

Specifically, a single mask in which the contact pattern 280 and the concavo-convex pattern 281 shown in FIG. 34 are drawn is used, and the light transmission amount of the contact pattern region at this time is more than the light transmission amount of the concavo-convex pattern. A mask is used in which the mask material 282 is controlled so as to be large. As a result, the exposed photosensitive acrylic resin 283
As a result of different irradiation energy depending on the pattern, a difference in etching amount occurs in the same development time, so that a region where a desired film thickness remains and a region where etching is completely completed can be realized at the same time.

In the present embodiment, by controlling the light transmission amount, the ratio of the transmission exposure amount was set to be 3: 1 between the contact pattern portion and the concavo-convex pattern portion. In the subsequent development process, the product name “NM manufactured by Tokyo Ohka Kogyo Co., Ltd.
By using "D-3", the film is completely removed in the contact area and the underlayer film is 2 μm in the concavo-convex area in the developing time of 90 seconds.
I was able to leave m.

In this example, the use of photosensitivity for the insulating film and the simultaneous formation of the concavo-convex and the formation of the contact pattern made it possible to manufacture the reflective liquid crystal display device on the TFT substrate side as compared with the first to fourth examples. The number of steps could be reduced.
In addition, PR in the manufacturing process on the TFT substrate side at this time
The number is 6, which is the TFT in the conventional reflective liquid crystal display device.
Since the number of manufacturing steps PR on the substrate side can be reduced to eight, a reflective liquid crystal display device can be provided at low cost.

Further, in this embodiment, the exposure amount was controlled by controlling the transmission amount of the mask material of the mask for simultaneously forming the concavo-convex pattern and the contact pattern. However, the concavo-convex pattern mask and the contact pattern mask are used, respectively. Two
It could also be achieved by performing one exposure. However, as for the exposure amount, it is necessary to make the contact pattern exposure amount larger than the uneven pattern exposure amount.

(Embodiment 6) FIG. 35 shows a sectional view of a reflective liquid crystal display device used in an embodiment of the present invention. In FIG. 35, reference numerals 290 are counter substrates, 291 are concave-convex reflectors,
292 is an uneven layer, 293 is a pixel electrode, 294 is a signal line,
295 is a liquid crystal layer, 296 is an insulating layer, and 297 is an MIM element.

As the switching element, an MIM diode element having a metal, an insulating film and a metal structure was adopted. Also in this case, as in the case of using a thin film transistor for the switching element, good display performance was obtained.

In all the drawings, the same parts are designated by the same reference numerals to omit redundant description.

[0137]

According to the reflective liquid crystal display device and the method of manufacturing the same according to the present invention, the insulating film having the concave-convex structure under the reflective electrode protects the switching element during the manufacturing process and has a different film thickness. By arranging the regions irregularly, it is possible to prevent the characteristic deterioration of the switching element during the manufacturing process, and it is possible to reduce the number of manufacturing processes because another film is not required for the concavo-convex structure.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a reflective liquid crystal display device according to the present invention.

FIG. 2 is a cross-sectional view showing a first embodiment of a method of manufacturing a reflective liquid crystal display device according to the present invention, and FIGS.
The steps proceed in the order of [e].

FIG. 3 is a cross-sectional view showing a second embodiment of a method of manufacturing a reflective liquid crystal display device according to the present invention, and FIGS.
The steps proceed in the order of [c].

FIG. 4 is a cross-sectional view showing a second embodiment of a method of manufacturing a reflective liquid crystal display device according to the present invention, and FIGS.
The steps proceed in the order of [f].

FIG. 5 is a cross-sectional view showing a third embodiment of a method of manufacturing a reflective liquid crystal display device according to the present invention, and FIGS.
The steps proceed in the order of [e].

FIG. 6 is a sectional view showing a second embodiment of a reflective liquid crystal display device according to the present invention.

FIG. 7 is a sectional view showing a third embodiment of a reflective liquid crystal display device according to the present invention.

FIG. 8 is a plan view of a mask pattern showing a fourth embodiment of a reflective liquid crystal display device according to the present invention, and FIG.
Is the first example, and FIG. 8B is the second example.

FIG. 9 is a plan view of a mask pattern showing a fifth embodiment of the reflective liquid crystal display device according to the present invention, and FIG.
Is the first example, and FIG. 9B is the second example.

FIG. 10 is an explanatory diagram showing a sixth embodiment of a reflective liquid crystal display device according to the present invention, FIG. 10 [a] being a first example, FIG. 10 [b] being a second example, and FIG. 10 [c]. Is the third example.

FIG. 11 is a cross-sectional view showing a comparative example in the fourth embodiment of the method of manufacturing a reflective liquid crystal display device according to the present invention,
The process proceeds in the order of FIG. 11 [a1] to FIG. 11 [f1].

FIG. 12 is a cross-sectional view showing a fourth embodiment of a method of manufacturing a reflective liquid crystal display device according to the present invention, and FIG.
The steps proceed in the order of FIG. 12 [c2].

FIG. 13 is a cross-sectional view showing a seventh embodiment of a reflective liquid crystal display device according to the present invention, FIG. 13 [a] being a first example and FIG. 13 [b] being a second example.

FIG. 14 is a cross-sectional view showing a fifth embodiment of a method of manufacturing a reflection type liquid crystal display device according to the present invention, and FIG.
The process proceeds in the order of FIG.

FIG. 15 is a cross-sectional view showing a fifth embodiment of a method of manufacturing a reflection type liquid crystal display device according to the present invention, and FIG.
The process proceeds in the order of FIG.

16 is a cross-sectional view showing a sixth embodiment of a method of manufacturing a reflective liquid crystal display device according to the present invention, and FIG.
The process proceeds in the order of FIG. 16 [3].

FIG. 17 is a cross-sectional view showing a sixth embodiment of a method of manufacturing a reflective liquid crystal display device according to the present invention, and FIG.
The process proceeds in the order of FIG. 17 [6].

FIG. 18 is a cross-sectional view showing a seventh embodiment of the method of manufacturing the reflection type liquid crystal display device according to the present invention, and FIG.
The process proceeds in the order of FIG.

FIG. 19 is a cross-sectional view showing a seventh embodiment of the method of manufacturing the reflective liquid crystal display device according to the present invention, and FIG.
The process proceeds in the order of FIG.

FIG. 20 is a cross-sectional view showing an eighth embodiment of the method of manufacturing the reflection type liquid crystal display device according to the present invention, and FIG.
The process proceeds in the order of FIG.

FIG. 21 is a cross-sectional view showing an eighth embodiment of a method of manufacturing a reflective liquid crystal display device according to the present invention, and FIG.
The process proceeds in the order of FIG. 21 [j].

FIG. 22 is a cross-sectional view showing the method of manufacturing the reflective liquid crystal display device according to the first embodiment of the present invention, which is shown in FIGS.
The process proceeds in the order of 2 [f].

FIG. 23 is a cross-sectional view showing the method of manufacturing the reflective liquid crystal display device according to Embodiment 1 of the present invention, and FIGS.
The process proceeds in the order of 3 [j].

FIG. 24 is a cross-sectional view showing a reflective liquid crystal display device according to Embodiment 1 of the present invention.

FIG. 25 is a cross-sectional view showing the method of manufacturing the reflection type liquid crystal display device according to the second embodiment of the present invention, and FIGS.
The steps proceed in the order of [g].

FIG. 26 is a cross-sectional view showing the method of manufacturing the reflective liquid crystal display device according to the second embodiment of the present invention, which is shown in FIGS.
The process proceeds in the order of 6 [l].

FIG. 27 is a cross-sectional view showing a reflective liquid crystal display device according to Embodiment 2 of the present invention.

FIG. 28 is a cross-sectional view showing the method of manufacturing the reflective liquid crystal display device according to Embodiment 3 of the present invention, which is shown in FIGS.
The process proceeds in the order of 8 [g].

FIG. 29 is a cross-sectional view showing the method of manufacturing the reflective liquid crystal display device according to the third embodiment of the present invention, which is shown in FIGS.
The process proceeds in the order of 9 [l].

FIG. 30 is a cross-sectional view showing the method of manufacturing the reflective liquid crystal display device according to Embodiment 4 of the present invention, which is shown in FIGS.
The process proceeds in the order of 0 [g].

FIG. 31 is a cross-sectional view showing the method of manufacturing the reflective liquid crystal display device according to Embodiment 4 of the present invention, which is shown in FIGS.
The process proceeds in the order of 1 [l].

FIG. 32 is a cross-sectional view showing the method of manufacturing the reflective liquid crystal display device according to Embodiment 5 of the present invention, and FIGS.
The process proceeds in the order of 2 [g].

FIG. 33 is a cross-sectional view showing the method of manufacturing the reflective liquid crystal display device according to Embodiment 5 of the present invention, which is shown in FIGS.
The process proceeds in the order of 3 [l].

FIG. 34 is a cross-sectional view showing the method of manufacturing the reflective liquid crystal display device according to Embodiment 5 of the present invention.

FIG. 35 is a cross-sectional view showing a reflective liquid crystal display device according to Embodiment 6 of the present invention.

FIG. 36 is a cross-sectional view showing a conventional reflective liquid crystal display device.

FIG. 37 is a cross-sectional view showing the conventional method of manufacturing a reflective liquid crystal display device, in which the steps proceed in the order of FIGS. 37 [a] to 37 [f].

FIG. 38 is a cross-sectional view showing the conventional method of manufacturing a reflective liquid crystal display device, in which the steps proceed in the order of FIGS. 38 [g] to 38 [j].

[Explanation of symbols] 53 glass substrate (first substrate) 55 Transparent electrode 40 glass substrate (second substrate) 44 thin film transistor (switching element) 45 insulating film 45a Concavo-convex structure 48 reflective electrode 56 Liquid crystal layer

Continued front page    (72) Inventor Shuken Yoshikawa             5-7 Shiba 5-1, Minato-ku, Tokyo NEC Corporation             Inside the company F-term (reference) 2H090 HA03 HA04 HB03X HB06X                       HB08X HB13Y HC05 HC06                       HC11 HC12 HC15 HD06 JB02                       JB03 JB04 KA05 KA06 KA08                       KA11 LA01 LA04 LA09 LA16                       LA20                 2H091 FA08X FA11X FA16Y FA41Z                       FB04 FB06 FC13 FC22 FC26                       GA01 GA02 GA07 GA13 HA07                       HA08 HA10 JA02 KA10 LA03                       LA12 LA16                 2H092 GA12 GA29 JA03 JA25 JA26                       JA46 JB07 KA05 KB25 MA05                       MA08 MA13 MA14 MA15 MA17                       MA27 NA01 NA22 NA27 PA01                       PA09 PA12 QA07 QA08 QA10

Claims (15)

[Claims] 1. A transparent first substrate, a transparent electrode provided on the first substrate, a second substrate, a switching element provided on the second substrate, and the switching element. An insulating film provided on the upper surface and having an uneven structure formed on the surface thereof; a reflective electrode provided on the insulating film in a shape reflecting the uneven structure and connected to the switching element; and the first substrate. In a reflective liquid crystal display device comprising a liquid crystal layer sandwiched between the transparent electrode side and the reflective electrode side of the second substrate, the insulating film protects the switching element after the switching element formation. At the same time, the uneven structure is formed by irregularly arranging regions having different film thicknesses. 2. The reflective liquid crystal display device according to claim 1, wherein the concavo-convex structure has a continuous and smooth shape. 3. The reflective liquid crystal display device according to claim 1, wherein the insulating film is a single layer film made of the same material. 4. The insulating film has a light absorbing property, The reflective liquid crystal display device according to claim 1, 2, or 3. 5. The reflective liquid crystal display device according to claim 1, wherein the uneven structure comprises a plurality of protrusions arranged irregularly. 6. The reflection type liquid crystal display device according to claim 5, wherein the protrusion has an island-shaped or linear planar shape. 7. The reflection type liquid crystal display device according to claim 1, wherein the concave-convex structure is formed by arranging a plurality of recesses irregularly. 8. The reflective liquid crystal display device according to claim 7, wherein the recess has a hole-shaped or linear planar shape. 9. The reflective type structure according to claim 1, wherein the concavo-convex structure is formed by repeating irregular concavo-convex shapes in one pixel unit or two or more pixel units. Liquid crystal display device. 10. The reflective liquid crystal display device according to claim 1, wherein the insulating film is made of an organic resin or an inorganic resin having photosensitivity. 11. Claims 1, 2, 3, 4, 5, 6, 7,
A method for forming the concavo-convex structure in the reflective liquid crystal display device according to 8, 9, or 10, wherein a predetermined pattern is formed by performing photolithography on the insulating film, and a predetermined film thickness is left at this time. A method for manufacturing a reflection type liquid crystal display device, wherein the uneven structure is formed on the surface of the insulating film by patterning by patterning to form thin and thick regions in a plane and irregularly. 12. The method according to claim 1, 2, 3, 4, 5, 6, 7,
11. A method for forming the concavo-convex structure in the reflective liquid crystal display device according to 8, 9, or 10, comprising the steps of forming the insulating film, a photolithography step of forming a resist pattern on the insulating film, and the insulating film. A step of etching so as to leave a predetermined film thickness underneath,
A step of removing the resist film remaining on the insulating film, and a step of smoothing the concavo-convex structure by melting the insulating film after etching by heat treatment,
Manufacturing method of reflective liquid crystal display device. 13. The method according to claim 1, 2, 3, 4, 5, 6, 7,
A method of forming the concavo-convex structure in the reflective liquid crystal display device according to 8, 9, or 10, comprising: forming the insulating layer using an organic insulating material or an inorganic insulating material having photosensitivity; By an exposure step for forming a concavo-convex pattern on the insulating layer, a developing step of performing etching development so as to leave a desired film thickness under the insulating film, and melting the insulating film after the etching development by heat treatment. A method of manufacturing a reflective liquid crystal display device, comprising: a melt process for smoothing the uneven structure. 14. Claims 1, 2, 3, 4, 5, 6, 7,
A method for forming a contact hole for connecting the concavo-convex structure and the switching element to the reflective electrode in the reflective liquid crystal display device according to 8, 9, or 10, comprising an organic insulating material or an inorganic insulating material having photosensitivity. A step of forming the insulating layer using a material, an exposure step of forming a pattern for forming the concavo-convex structure and the contact hole in the insulating film, and leaving a predetermined film thickness with respect to the insulating film. A method of manufacturing a reflection type liquid crystal display device, comprising: a developing step of forming the concavo-convex structure and simultaneously forming the contact hole. 15. The reflective liquid crystal according to claim 14, wherein a positive type is used as the photosensitive performance, and an exposure amount for forming the contact hole pattern is larger than an exposure amount for forming the pattern of the concavo-convex structure. Manufacturing method of display device.