JPH08313890A - Liquid crystal display element and its production - Google Patents

Abstract

PURPOSE: To provide a reflection type liquid crystal display element having a reflection plate possessing good reflection performance by using substrates subjected to surface roughening before formation of switching elements and having good image quality by simplifying the production process for the reflection type liquid crystal element having a light reflection layer between a liquid crystal layer and the substrates. CONSTITUTION: This liquid crystal display element is constituted by arranging the first substrate having active elements, gate electrodes 41 for driving these active elements and the light reflection plate 40 in common use as pixel electrodes to receive the charges from the active elements on a substrate surface 46 having irregular ruggedness on the front surface and the second substrate attached with transparent electrodes on the front surface in such a manner that the respective front surface face to the inside surfaces and sealing liquid crystals contg. dichromatic dye into the spacing formed by the first and second substrates. Three-terminal or two-terminal elements, such as transistors and diodes, are used as the active elements. The active elements are formed on the substrates which are not flattened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix substrate for a reflective liquid crystal display.

[0002]

2. Description of the Related Art Recently, with the expansion of the market of portable computers, information devices meeting various needs have been proposed. As one of the key technologies to achieve this, Liquid Crystal Display (“L”)
"CD").

LCDs in recent years are laptop personal computers,
Since it was developed as a display device for devices intended for use on desktops such as desktop personal computers, word processors, and workstations, higher image quality of display performance was prioritized for LCDs than for portability. As a result, a TN (Twisted Nematic) liquid crystal adopting a backlight as a light source or an STN (Super Twisted Nematic) liquid crystal transmission type LCD system has become mainstream.

However, the transmissive LCD system requires a backlight, and thus has a problem that it is difficult to reduce the size and weight of the information device and to use it for a long time. And this is a factor that prevents the progress of portable information devices.

On the other hand, an LC suitable for portable information equipment
As D, it is considered to adopt a reflection type LCD in which a reflection plate is provided instead of the backlight and the reflected light of external incident light is used as a light source. In this case, in order to obtain a bright display performance only with external light, the guest-host (G
The H) method is adopted, and a method of disposing a reflection plate between the liquid crystal layer and the glass substrate is being studied (for example, literature,
"S. Mitsui et al.," Bright Reflective Multicolor
LCDs Addressed by a-Si TFTs ”, Proc.SID, page 437”
reference).

A specific structural example of this conventional method will be described below with reference to FIG.

After forming a thin film transistor (TFT) 11 on a flat lower glass substrate 10, the TFT 11 is formed.
An insulating layer (also called “thick film insulator”) 5 is arranged on the upper part,
Further, irregularities are formed on the surface of the insulating layer 5.

On the insulating layer 5, a metal reflection plate (also referred to as "reflection pixel electrode", "reflection plate / electrode" or "reflection plate electrode") 4 which also serves as a pixel electrode for driving liquid crystal is formed. .

A glass substrate (also referred to as "lower glass substrate") 10 having a reflector electrode 4 driven by a TFT 11
And the opposite side glass substrate (also referred to as “upper glass substrate”) 1 having the transparent electrode 2 as a liquid crystal layer.
A host (GH) type liquid crystal 3 is provided.

The unevenness of the surface of the reflector plate electrode 4 which also serves as the pixel electrode has a function of efficiently reflecting incident light from a wide range to the front of the panel and, at the same time, eliminating coloring such as interference color.

As an example of a method of manufacturing the reflector electrode 4, a photolithography technique or an etching technique is applied to the surface of the insulating layer 5 to form irregularities having a height of about several μm, and the upper portion thereof is a metal having high reflection efficiency. The method of covering with is adopted.

[0012]

The above manufacturing process is basically the same as the conventional transmissive LCD manufacturing process in order to further form a reflector electrode, an insulating film forming process, an uneven forming process, and a contact forming process process. Is added.

However, in this case, the manufacturing cost increases as the number of steps increases.

Further, as described above, since the unevenness is formed after the active element is manufactured, the active element is damaged (damage,
It is an absolute condition in the production of the reflector to avoid giving the device characteristics). This has made it difficult to realize a reflective liquid crystal display device having a high-performance reflector.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a reflection type liquid crystal display device having a reflection plate having a good reflection characteristic at a low cost and a manufacturing method thereof. And

[0016]

In order to achieve the above object, the present invention controls a light reflection plate arranged in a matrix and also serving as a pixel electrode, and a write charge to the pixel electrode for each pixel electrode. An active element, and a first wiring including predetermined wiring for operating the active element
And a second substrate having a transparent electrode facing the pixel electrode, and a liquid crystal layer interposed between the first and second substrates. There is provided a liquid crystal display element, wherein the first substrate surface has a predetermined unevenness, and the active element is formed on the unevenness of the first substrate.

The present invention is provided with a light reflecting plate arranged in a matrix and also serving as a pixel electrode, and an active element for controlling a write charge to the pixel electrode for each pixel electrode, and the active element is operated. A liquid crystal layer interposed between a first substrate provided with a predetermined wiring for controlling the pixel electrode, a second substrate provided with a transparent electrode facing the pixel electrode, and the first and second substrates. A liquid crystal display element including: and the first substrate is provided with irregularities only in a region corresponding to a region where the light reflection plate is formed, and the active element is formed on a flat region of the first substrate. A liquid crystal display element is provided.

In the present invention, preferably the first
Of the active element and / or the flattening region having an unevenness on the entire surface of the substrate and having an organic film or an inorganic film selectively formed on the uneven region with a predetermined thickness. The wiring is formed on the flattened region.

In the present invention, preferably the first
Of the substrate has unevenness on the entire surface of the substrate, and has a flattening region formed by flattening the unevenness by an etching process, and the active element and / or the wiring is formed on the flattening region. And

In the present invention, preferably the first
The substrate is mirror-finished, and the first substrate surface has irregularities only in the region corresponding to the region where the light reflection plate is formed.

In the present invention, preferably, the active element is a transistor.

In the present invention, it is preferable that the transistor has a semiconductor layer arranged only above a gate electrode.

In the present invention, preferably, in the transistor, the upper surface of the gate electrode patterned on the first substrate is entirely covered with an insulating layer, a semiconductor layer, and a resist layer. A resist pattern reflecting the shape of the gate electrode is formed on the uppermost portion by exposing from the back surface of the substrate, and a semiconductor layer is patterned using the resist pattern to form a self-alignment process. To do.

In the present invention, preferably, the transistor is characterized in that the periphery of the gate electrode and the gate signal line is covered with an insulating film.

In the present invention, preferably, the active element is a two-terminal type non-linear resistance element.

In the present invention, preferably, the non-linear resistance element of the first substrate is entirely covered with an insulating layer and a resist layer on an upper portion of the signal wiring patterned on the first substrate. Exposure is performed from the back surface using a stripe-shaped mask that is orthogonal to the signal wiring, and a resist pattern reflecting the shape of the signal wiring and the mask shape is formed on the uppermost portion, and the insulating layer is patterned using the resist pattern. It is characterized in that it is formed by a self-aligning process.

In the present invention, preferably, in the two-terminal type non-linear element, the non-linear element is composed of a wiring for supplying a signal and a light reflection plate which also serves as an insulating film on a side wall of the wiring and a pixel electrode. It is characterized by being.

In the present invention, preferably the first
Unevenness on the substrate surface of 0.5 to 10 μm in height,
It is characterized in that the pitch is randomly arranged between 1 μm and 30 μm.

Further, the present invention comprises a light reflection plate arranged in a matrix and also serving as a pixel electrode, and an active element for controlling a write charge to the pixel electrode for each pixel electrode, and the active element. And a first substrate provided with a predetermined wiring for activating, a second substrate provided with a transparent electrode facing the pixel electrode, and the first and second substrates. In a method for manufacturing a liquid crystal display device including a liquid crystal layer, the first substrate is provided with unevenness of a predetermined height in at least a region corresponding to a region where the light reflection plate is formed. The resist pattern reflecting the shape of the gate electrode is formed by exposing from the back side of the first substrate using the pattern of the gate electrode formed above, and the semiconductor pattern including the semiconductor layer is formed using the resist pattern. Active element An active layer is formed in a self-aligned manner, a side wall of the gate electrode is covered with an insulating film by anodic oxidation, and the light reflection plate is formed on an uneven region of the first substrate. A manufacturing method is provided.

Further, the present invention comprises a light reflecting plate arranged in a matrix and also serving as a pixel electrode, and an active element for controlling a write charge to the pixel electrode for each pixel electrode, and the active element And a first substrate provided with a predetermined wiring for activating, a second substrate provided with a transparent electrode facing the pixel electrode, and the first and second substrates. A method of manufacturing a liquid crystal display device including a liquid crystal layer, wherein the first substrate is provided with unevenness only in a region corresponding to a region where the light reflection plate is formed, and a flat region is formed in a region where the active element is formed. Forming the top,
An active layer of the active element including a semiconductor layer is formed on a flat region on the first substrate, a sidewall of the gate electrode is covered with an insulating film by anodic oxidation, and the light reflection plate is formed on the first substrate. Provided is a method for manufacturing a liquid crystal display element, which is characterized in that it is formed on an uneven region.

In the present invention, preferably, the gate electrode pattern is used to expose from the back side of the first substrate to expose the upper portion of the gate electrode to an insulating layer, a semiconductor layer,
The first substrate, which is entirely covered with a resist layer, is exposed from the back side, and the active layer of the active element including the semiconductor layer is formed in a self-aligned manner by using the resist pattern.

The present invention further comprises a light reflection plate arranged in a matrix and also serving as a pixel electrode, and an active element for controlling the write charge to the pixel electrode for each pixel electrode, and the active element is also provided. And a first substrate provided with a predetermined wiring for activating, a second substrate provided with a transparent electrode facing the pixel electrode, and the first and second substrates. In a method of manufacturing a liquid crystal display element including a liquid crystal layer, a concave and convex portion having a predetermined height is formed at least in a region corresponding to a region where the light reflection plate is formed on the surface of the first substrate, and the active element includes: An insulating layer covers the upper portion of the signal wiring patterned on the first substrate,
The non-linear element is formed of a two-terminal type on the sidewall of the signal wiring, and the non-linear element covers the entire surface of the signal wiring patterned on the first substrate with an insulating layer and a resist layer. 1 is exposed from the back side of the substrate using a stripe-shaped mask orthogonal to the signal wiring to form a resist pattern reflecting the shape of the signal wiring and the mask shape, and the insulating layer is patterned using the resist pattern. The light-reflecting plate, which is formed by a self-aligning process and which is exposed by patterning the insulating layer, is covered with an insulating film by anodic oxidation, and the light reflection plate which also serves as the pixel electrode is formed into an uneven region of the first substrate. Provided is a method for manufacturing a liquid crystal display device, which is characterized by being formed on an upper part.

[0033]

The function and details of the present invention will be described below.

FIG. 1 is a view for explaining a preferred embodiment of the reflective liquid crystal display device of the present invention. 1A and FIG.
FIGS. 1B and 1C are views for explaining a case where a glass substrate having an uneven surface is used as the first insulating substrate 18, and FIG. 1D is a glass substrate in a mirror state. FIG. 6 is a diagram for explaining a case where is used as a first insulating substrate 22. In FIG. 1, 13 is a source electrode, and 14
Is a drain electrode, 15 is a reflection plate (referred to as “reflection-type pixel electrode”), 16 is a gate insulating film, 17 is a gate electrode, 18
Is a glass substrate (also referred to as a "roughened glass substrate" or "first insulating substrate"), 19 is a flattening film, 20 is a flat region,
Reference numeral 21 denotes a semiconductor layer, and 22 denotes an unevenness forming layer.

With reference to FIG. 1A, according to the present invention,
A first insulating substrate 18 having a reflecting plate 15 having irregularities as a pixel electrode and having a switching element connected to the reflective pixel electrode 15 for active matrix driving.
And a first insulating substrate 18 of a reflective liquid crystal display device having a structure in which a liquid crystal layer is sandwiched by a second insulating substrate (not shown) having a transparent electrode located on the opposite side. 1
A substrate having irregularities in the range of 0 μm is used.

On the uneven upper surface of the first insulating substrate 18,
Switching element (gate electrode 17, gate insulating film 1
6, semiconductor layer 21, and source / drain electrodes 13, 1
The transistor element having the inverted stagger structure 4) and the reflector 15 are directly formed.

With this, since the concavo-convex forming process can be performed before the switching element is formed, the concavo-convex shape can be freely formed without being restricted by the process. Therefore, it is possible to provide a reflector having good reflection performance with good reproducibility.

Furthermore, since the concavo-convex forming step is performed before the switching element forming step, there is no damage given to the switching element by the concavo-convex forming step, so that good panel display performance can be obtained.

Alternatively, as shown in FIG. 1B, a flattening film 19 is formed on a portion of the first insulating substrate 18 having irregularities and flattened, and a switching element and a switching element are formed on the flattening film 19. Form the wiring. Alternatively, as shown in FIG. 1C, a part of the first insulating substrate 18 having unevenness is flattened (see the flat region 20) and the switching element and the wiring are formed on the flat region 20. May be.

As a result, the above-described action and the flat portion 1
Since the switching elements and the wirings are formed on the layers 9 and 20, the reproducibility and the uniformity and reliability of the element performance are improved.

Further, referring to FIG. 1D, a mirror-polished flat substrate is used as the first insulating substrate 18, switching elements and wirings are formed on the flat substrate, and at the same time, on the reflection plate forming region. Even when a substrate having a region in which unevenness is formed only (see the unevenness forming layer 22) is used, the same effect as the above can be obtained.

In FIG. 1, the inverse stagger structure is used as an example of the TFT (thin film transistor) structure.
Even when the forward (positive) stagger structure is adopted, the same operation as described above can be obtained.

FIG. 2 is a diagram schematically showing a method of manufacturing a thin film transistor having an inverted stagger structure according to the present invention in the order of steps. In FIG. 2, 27 is roughened glass (first insulating substrate) having an uneven surface, 23 is a gate electrode, 24 is a gate insulating layer, 25 is a semiconductor layer, 26 is a resist layer, 28
Is an anodized film layer, 29 is a source electrode, and 30 is a reflective pixel electrode plate.

According to the present invention, the pattern of the gate electrode formed on the first insulating substrate 27 (see FIG. 2A).
The active layer including the semiconductor layer 25 is self-aligned by the backside exposure process using the (see FIG. 2).
(B)).

After that, the side wall of the gate electrode 23 is covered with an insulating film by anodic oxidation (the anodic oxide film layer 28 of FIG. 2C).
(See FIG. 2D).

Thus, by using the backside exposure process, the switching element can be patterned regardless of the deterioration of the alignment accuracy due to the influence of the substrate irregularities. As a result, the stability and reliability of the switching element performance can be ensured, and variations in element characteristics between elements can be eliminated. Furthermore, since the photolithography process is only two processes, there is an effect that the cost can be reduced.

The present invention also relates to FIG.
Similar effects can be obtained by using the substrates of (A), FIG. 1 (B), FIG. 1 (C), and FIG. 1 (D) as the first insulating substrate.

According to the present invention, a diode having a metal / insulating film / metal (MIM) structure is used in place of the TFT which is an active matrix driving switching element as shown in FIG.
Even in the case of manufacturing on the substrate of (A), FIG. 1 (B), FIG. 1 (C), and FIG. 1 (D), since the reflecting plate concavo-convex structure can be formed before the diode is manufactured, good reflecting performance is obtained. It is possible to provide a liquid crystal display device having the reflecting plate.

3 and 4 are diagrams schematically showing the order of steps in the method of manufacturing the MIM structure diode according to the present invention.

According to the present invention, the resist layer 34 and the insulating layer 33 are self-aligned by the backside exposure process using the lower signal line 32 pattern (see FIG. 3A) (FIG. 3B, FIG. 3 (C)).

Thereafter, the lower signal electrode side wall 35 is covered with the insulating film (see FIG. 4D), so that the upper reflective pixel electrode plate 36 and the lower signal electrode 32 are electrically insulated (see FIG. 4 ( See E)).

By using the back exposure process, the switching element can be patterned regardless of the misalignment, so that the stability and reliability of the switching element performance can be secured and the variation of the element characteristic is eliminated. Have.

Further, the number of photolithography processes is basically (1)
There are three steps of signal line pattern formation, (2) insulating film pattern formation (back exposure), and (3) reflective pixel electrode formation, and a reflective liquid crystal display element can be provided at low cost.

In the present invention, the same effect can be obtained even if the above-mentioned substrates of FIGS. 1 (A), 1 (B), 1 (C) and 1 (D) are used as the first substrate. can get.

[0055]

Embodiments of the present invention will be described below with reference to the drawings.

[0056]

Example 1 As an example of the present invention, a liquid crystal display element produced by using a transistor as a switching element will be described.

FIG. 5 shows a plan view for explaining the TFT element prepared according to this embodiment. 6 is a sectional view taken along the line AA ′ of FIG. 5, and FIG.
A sectional view taken along line B ′ is shown.

In this embodiment, as the lower substrate 46, roughened glass polished with abrasive # 1000 is used.

The height of the glass substrate surface after polishing is 1
Irregular irregularities with an acute angle of about 10 μm are formed.

The glass substrate was etched in a 50% aqueous solution of hydrofluoric acid at 25 ° C. for 40 seconds to form a smooth uneven surface. As a result, a concave-convex surface with good reflection performance was formed on the entire surface of the lower substrate 46. By changing the etching treatment time, it was possible to variably control the inclination angle of the unevenness.

After that, the gate electrode 4 is formed on the lower substrate 46.
1, Ta was vapor-deposited with a film thickness of 300 nm by a sputtering method, and SiN was used as the gate insulating film 45 with a film thickness of 500 nm.
Amorphous silicon is used as the semiconductor layer 44 and has a thickness of 300.
nm, and a film was continuously formed by a plasma CVD (chemical vapor deposition) method.

Next, patterning processing was performed on the shape of the gate electrode 41 (a strip shape having a width of 5 μm).

At this time, the unevenness of the substrate surface causes a focus shift in the exposure apparatus, making it difficult to keep the alignment accuracy within the guaranteed range.

Therefore, in this embodiment, a backside exposure process is used in which the backside of the lower substrate 46 is exposed, and a resist pattern having the same shape as the gate electrode shape is formed using the gate electrode 41 as a mask. As described above, by forming the resist pattern by using the back exposure, it was possible to solve the above-mentioned problem caused by the focus shift.

Further, at the time of back exposure, light enters inside the gate mask region due to light scattering due to the unevenness of the glass surface, and the mask region becomes smaller than the gate region.

In order to prevent this, in this embodiment, as the resist layer, a photosensitive organic film having the same refractive index as that of the glass substrate is formed with a film thickness of 1 μm or more. As a result, the uneven surface is flattened to eliminate the light scattering surface, and a resist pattern having the same shape as the gate electrode can be formed.

Next, while leaving the etched resist in the shape of the gate electrode 41, the substrate is immersed in a 0.1 wt% citric acid aqueous solution and anodized at a constant voltage of 2 V to form an anodized film 47. It was formed on the side wall of the gate electrode. At this time, the resist layer is used as a protective film of amorphous silicon to prevent contamination by the electrolytic solution (0.1 wt% citric acid aqueous solution in this case).

Then, aluminum was vapor-deposited to form pixel electrodes and signal electrodes 43. In this embodiment, FIG.
The channel length a was 3 μm, and the distance b between the signal line and the adjacent pixel was 30 μm.

After that, a step of exposing terminals of the lower substrate 49 around the display portion is performed.

If the a-Si layer (amorphous silicon layer) of the TFT element portion is formed into an island in the step of FIG. 3B, generation of a parasitic transistor between the drain signal line and an adjacent pixel can be prevented. be able to.

As a transparent conductive film on the surface of the TFT substrate and the glass substrate, Indium-Tin-Oxide (Indium-Tin-Oxide;
A glass substrate on which “ITO” was vapor-deposited was laminated with the film surface facing inward.

The TFT substrate and the upper glass substrate are subjected to an orientation treatment, and a spacer such as plastic particles is interposed between the two substrates, and an epoxy adhesive is applied to the peripheral portion of the substrates. .

After that, a GH type liquid crystal was injected to form a liquid crystal layer, thereby forming a liquid crystal element.

The liquid crystal display device according to this example manufactured according to the above manufacturing process had a contrast ratio and whiteness comparable to those of the conventional reflection type liquid crystal panel.

The channel length, the distance between the signal line and the adjacent pixel (see a and b in FIG. 7) and the like in the liquid crystal display device prototyped this time are merely examples, and the present invention is not limited thereto. is not.

Further, in this embodiment, aluminum metal is used as the pixel electrode and light reflecting plate, but the same effect can be obtained when silver or metal is used as the multilayer film.

[0077]

Second Embodiment A second embodiment of the present invention will be described below.
In this example, a polyimide film (RN-812 manufactured by Nissan Chemical Industries, Ltd.) was formed on the glass substrate in the range of 1 to 10 μm, and then the surface of the polyimide film was polished and etched to form irregularities.

The substrate having this irregular asperity is used as the first insulating substrate 18 (see FIG. 1, corresponding to the lower substrate 46 in FIG. 6).
Then, a TFT was prepared in the same manner as in the first embodiment. The reflection type liquid crystal display panel thus obtained is
The same display performance as that of the first embodiment could be obtained.

[0079]

Third Embodiment Next, a third embodiment of the present invention will be described.
In this embodiment, a ceramic substrate made by sintering silicon nitride is used as the first insulating substrate of the reflective liquid crystal device, and the first insulating substrate is used.
A liquid crystal display device was manufactured by using the same process as in the above example. As a result, it was possible to obtain the same display performance as that of the first embodiment.

[0080]

Fourth Embodiment Next, a fourth embodiment of the present invention will be described.
In this example, a reflective liquid crystal display device was experimentally manufactured by using a substrate of a roughened glass substrate in which a TFT and a region where wirings were formed were flattened in advance.

A roughened glass substrate was used as a first insulating substrate as a substrate for manufacturing TFTs, and a photoresist process was used to form a resist (OFPR-800C: manufactured by Tokyo Ohka Co., Ltd.) except for regions where TFTs and wirings were formed. ),
After that, the uneven portion was etched with a hydrofluoric acid aqueous solution.

A 50% concentration was used as the etching solution, and the unevenness was wet-etched for 1 to 10 minutes. By this step, the uneven height of the etching region is reduced from 2 μm on average to 0.1 μm or less (see FIG. 8). FIG.
Is the average height of irregularities (vertical axis) and etching time (horizontal axis)
It is a figure which shows the relationship with.

After removing the resist, by the same manufacturing process as described in the first embodiment, TFTs and wirings were formed in the etched flat area, and a reflection plate was formed in the uneven area.

Although wet etching was used for the etching treatment of this embodiment, the same effect can be obtained by a dry etching process using a mixed gas of carbon tetrafluoride (CF ₄ ) and oxygen (O ₂ ). It was The dry etching conditions at that time are 20 sccm of CF ₄ and 20 s of O ₂ .
The reaction pressure was 0.1 Torr and the plasma power was 250 W. In particular, when dry etching is used, anisotropic etching is possible, so that a flat region (see FIGS. 1C and 1D) can be accurately formed.

As described above, in this embodiment, as in the case of the first embodiment, the reflection type liquid crystal display element having the bright display performance could be realized.

[0086]

Fifth Embodiment Next, a fifth embodiment of the present invention will be described.
In this example, a reflective liquid crystal display device was experimentally manufactured using a mirror-polished glass substrate in which only the region where the reflection plate was formed was made uneven. FIG. 9 is a diagram schematically illustrating the manufacturing method according to this embodiment in the order of steps.

A mirror-polished glass substrate 49 is used as a first substrate for forming a TFT, and then a photoresist process is performed to cover a region 50 where TFTs and wirings are to be formed with a resist layer 48 to form a reflective electrode plate. A pattern is irregularly arranged in a region 51 forming 52 (FIG. 9).
(A)).

Then, the glass substrate 49 was etched with a hydrofluoric acid aqueous solution. The etching solution was treated at a concentration of 50% for 1 to 6 minutes. The average height of the unevenness formed by etching in this step is 1 μm.
To 2 μm.

FIG. 9B schematically shows a cross section of the glass substrate 49 obtained by the above etching. The region 50 is a flat region on which TFTs and wirings are formed,
A reflective electrode plate 52 is provided on the area 51 where the surface is uneven.
Is formed

That is, in this embodiment, the unevenness is formed only in the formation region of the reflective electrode plate 52, and the TFT and the wiring region 53 can maintain the initial flat state.

After stripping the resist, the TFT, the wiring, and the reflector are formed by the same manufacturing process as described in the first embodiment (see FIG. 9C).

Incidentally, as the etching method, the same result can be obtained by performing the dry etching treatment as in the case of the fourth embodiment.

As described above, in the present embodiment, a reflective liquid crystal display element having a bright display performance could be realized as in the first embodiment.

[0094]

Sixth Embodiment Next, a sixth embodiment of the present invention will be described.
In this example, a prototype was made using an MIM diode as a switching element. 10, 11, and 1
2 and 13 are views for explaining the present embodiment.

As the lower substrate 58 for making the prototype panel in this embodiment, the roughened glass substrate obtained by polishing with the abrasive # 1000 described in the first embodiment is used as the lower substrate 58 with a 50% concentration. What was etched for 40 seconds in acid was used.

A lead electrode 5 is formed on the roughened glass substrate.
As No. 6, Ta was formed by a sputtering method with a film thickness of 500 nm, and etching was performed so as to have a strip shape with a width of 10 μm.

After removing the resist, Si is used as an insulating film 59.
An O ₂ film was deposited to a thickness of 500 nm.

After applying the resist 54, back exposure is performed from the back surface of the substrate (surface not coated with the resist) so that slit-shaped light having a width of 10 μm and a pitch of 100 μm is orthogonal to the lead electrodes.

After the development, the insulating film 59 was etched. A plan view at this time is shown in FIG.
1A and 1B are diagrams schematically showing a cross section taken along line cd.
1 (B), respectively.

After that, the lead wire side wall portion 61 has a thickness of 0.1 w.
It was anodized by immersing in a t% aqueous solution of citric acid and applying a constant voltage of 2V. As a result, FIG.
The surface of the exposed portion of the lead electrode 56 in (A) is covered with the anodized insulating thin film 61 (see FIG. 11C).

Finally, an aluminum layer which is the light reflection plate / electrode 60 is vapor-deposited and etched into a pixel shape to form a light reflection plate / electrode, and the space between the lead wire / side wall anodic oxide film / reflection pixel electrode plate is formed. MIM element is formed by (Fig. 1
1 (C)).

FIG. 12 is a perspective view schematically showing the completed reflective liquid crystal display element. In addition, A- in FIG.
13 and 14 are cross-sectional views taken along the line A'and the line BB ', respectively.

After that, a counter substrate in which the above MIM substrate and ITO of the transparent conductive film were formed in a strip shape in a direction orthogonal to the lead electrodes was laminated so that their respective film surfaces face each other.

The MIM substrate and the counter substrate were subjected to orientation treatment, and both substrates were bonded together by applying an epoxy adhesive to the peripheral portion of the panel through a spacer such as plastic particles.

After that, a GH type liquid crystal was injected to form a liquid crystal layer to obtain a liquid crystal element.

The liquid crystal panel obtained according to the present invention had the same contrast ratio and whiteness as the conventional liquid crystal panel. Therefore, it is shown that the present invention can provide a reflective liquid crystal display device having low cost and good display performance.

Although the present invention has been described with reference to each of the above embodiments, the present invention is not limited to the above embodiments, and it is needless to say that various embodiments conforming to the principle of the present invention are included.

[0108]

As described above, according to the present invention,
Before manufacturing switching elements, wiring, etc. in an active drive reflective liquid crystal display element having a liquid crystal driving non-linear element inside the liquid crystal element and a light reflecting plate inside the liquid crystal element, the surface of the reflector plate is previously formed on the substrate. Since it is possible to create an uneven surface to be used for, it becomes possible to reduce the cost of the liquid crystal element panel and form the unevenness of the reflecting plate having the optimum reflection performance. Furthermore, by the backside exposure treatment in the manufacturing process of the active matrix driving element. By self-aligning the elements, there is an effect that it is possible to obtain an active element having no variation in element characteristics and having excellent switching performance.

Further, according to the manufacturing method of the present invention, by using the backside exposure process, the switching element can be patterned regardless of the deterioration of the alignment accuracy due to the influence of the substrate unevenness. The stability and reliability of the switching element performance can be ensured, the variation in element characteristics between elements can be reduced and avoided, and the cost can be reduced because the photolithography process is only two steps.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a reflective liquid crystal display device according to the present invention.

FIG. 2 shows a TF in the reflective liquid crystal display device according to the present invention.
It is a figure for demonstrating T manufacturing process in process order.

FIG. 3 shows MI in the reflective liquid crystal display element according to the present invention.
It is a figure for demonstrating M manufacturing process in process order.

FIG. 4 shows MI in the reflective liquid crystal display element according to the present invention.
It is a figure for demonstrating M manufacturing process in process order.

FIG. 5 is a plan view of a TFT active matrix drive reflective liquid crystal device according to an embodiment of the present invention.

6 is a diagram showing a cross section taken along line AA ′ of FIG.

FIG. 7 is a view showing a cross section taken along line BB ′ of FIG.

FIG. 8 is a diagram showing a relationship between an average height of surface roughness of a roughened glass and an etching rate.

FIG. 9 is a diagram for explaining a manufacturing process of a reflective liquid crystal display element using a mirror-finished glass substrate in another embodiment of the present invention in the order of steps.

FIG. 10 is a plan view for explaining a manufacturing process of a MIM active matrix drive reflective liquid crystal element in still another embodiment of the present invention in the order of steps.

FIG. 11 is a diagram for explaining a manufacturing process of the MIM active matrix drive reflective liquid crystal element in still another embodiment of the present invention in the order of steps.

FIG. 12 is a perspective view of an MIM substrate in a MIM active matrix drive reflective liquid crystal device formed on a random uneven surface according to an embodiment of the present invention.

13 is a diagram showing a cross section taken along line AA ′ of FIG.

14 is a diagram showing a cross section taken along line BB ′ of FIG.

FIG. 15 is a view showing a cross section of a conventional TFT driving reflection type liquid crystal display element.

[Explanation of symbols]

 1 Upper Glass Substrate 2 Transparent Electrode 3 Guest / Host Type Liquid Crystal 4 Reflector / Electrode 5 Thick Film Insulator 6 Amorphous Silicon 7 Lead Electrode 8 Gate Insulating Film 9 Gate Electrode 10 Lower Glass Substrate 11 TFT 12 Passivation 13 Source Electrode 14 Drain Electrode 15 Reflective Pixel Electrode 16 Gate Insulating Film 17 Gate Electrode 18 Roughened Glass Substrate 19 Flattening Film 20 Flat Region 21 Semiconductor Layer 22 Uneven Layer 23 Gate Electrode 24 Gate Insulating Layer 25 Semiconductor Layer 26 Resist Layer 27 Roughened Glass 28 Anodized film layer 29 Source electrode 30 Reflective pixel electrode plate 31 Lower substrate 32 Signal line 33 Insulating layer 34 Resist layer 35 Anodized layer 36 Reflective pixel electrode plate 37 Pixel electrode 1 38 Pixel electrode 2 39 Pixel electrode 3 40 Pixel electrode 4 41 Gate electrode 42 TFT section 43 Signal electrode 44 Semiconductor layer 45 Gate insulating film 46 Lower substrate 47 Anodized film 48 Resist layer 49 Lower substrate 50 Flat Region 51 Concavo-convex part 52 Reflective electrode plate 53 TFT and wiring formation part 54 Resist layer 55 Lower substrate 56 Lead electrode 57 MIM diode formation region 58 Lower glass substrate 59 Insulation film 60 Light reflection plate / electrode 61 Anodized insulation thin film

Claims (17)

[Claims] 1. A light reflection plate, which is arranged in a matrix and also serves as a pixel electrode, and an active element for controlling a write charge to the pixel electrode for each pixel electrode, and for operating the active element. A first substrate provided with a predetermined wiring, a second substrate provided with a transparent electrode facing the pixel electrode, a liquid crystal layer interposed between the first and second substrates, A liquid crystal display element including: a surface of the first substrate having a predetermined unevenness, and the active element formed on the unevenness of the first substrate. 2. A light reflection plate arranged in a matrix also serving as a pixel electrode, and an active element for controlling a write charge to the pixel electrode for each pixel electrode, and for operating the active element. A first substrate provided with a predetermined wiring, a second substrate provided with a transparent electrode facing the pixel electrode, a liquid crystal layer interposed between the first and second substrates, In a liquid crystal display device including: the first substrate is provided with unevenness only in a region corresponding to the formation region of the light reflection plate, and the active element is formed on a flat region of the first substrate. Liquid crystal display device. 3. A flattening region in which the first substrate has unevenness on the entire surface of the substrate, and an organic film or an inorganic film is selectively formed on the uneven region to a predetermined thickness. The liquid crystal display element according to claim 2, further comprising: the active element and / or the wiring formed on the flattening region. 4. The first substrate is provided with a flattened region having an unevenness on the entire surface of the substrate, and the unevenness is flattened by an etching process, and the active element and / or the wiring is on the flattened region. 3. The liquid crystal display element according to claim 2, wherein the liquid crystal display element is formed. 5. A mirror surface of the first substrate, wherein the first substrate surface has irregularities only in a region corresponding to a region where the light reflection plate is formed. Liquid crystal display device. 6. The liquid crystal display element according to claim 1, wherein the active element is a transistor. 7. The transistor according to claim 5, wherein the semiconductor layer is arranged only on the gate electrode.
The liquid crystal display element described. 8. The transistor exposes the patterned gate electrode upper portion on the first substrate upper portion from the back surface of the first substrate entirely covered with an insulating layer, a semiconductor layer, and a resist layer. The resist pattern reflecting the shape of the gate electrode is formed on the uppermost portion, and the semiconductor pattern is formed by a self-alignment process in which the semiconductor layer is patterned using the resist pattern. Liquid crystal display device. 9. The liquid crystal display element according to claim 7, wherein the transistor has a gate electrode and a gate signal line surrounded by an insulating film. 10. The liquid crystal display element according to claim 1, wherein the active element is a two-terminal type non-linear resistance element. 11. The non-linear resistance element is connected to the signal wiring from the back surface of the first substrate which is entirely covered with an insulating layer and a resist layer on the upper portion of the signal wiring patterned on the first substrate. Exposure is performed using orthogonal stripe-shaped masks, a resist pattern reflecting the shape of the signal wiring and the mask shape is formed on the uppermost portion, and the insulating layer is patterned using the resist pattern in a self-alignment process. The liquid crystal display element according to claim 10, which is formed. 12. The two-terminal type non-linear element, wherein the non-linear element is composed of a wiring for supplying a signal and a light reflection plate which also serves as an insulating film on a side wall of the wiring and a pixel electrode. The liquid crystal display device according to claim 10. 13. The unevenness of the surface of the first substrate has a height of 0.5 μm to 10 μm and a pitch of 1 μm to 30 μm.
The liquid crystal display element according to claim 1 or 2, wherein the liquid crystal display elements are randomly arranged. 14. A light reflection plate arranged in a matrix and also serving as a pixel electrode, and an active element for controlling a write charge to the pixel electrode for each pixel electrode, and for operating the active element. 1st with a predetermined wiring of
And a second substrate having a transparent electrode facing the pixel electrode, and a liquid crystal layer interposed between the first and second substrates. And forming a concavo-convex pattern of a predetermined height on at least a region corresponding to the region where the light reflection plate is formed on the surface of the first substrate, and using the pattern of the gate electrode formed on the first substrate. Exposing from the back side of the first substrate to form a resist pattern reflecting the shape of the gate electrode, and using the resist pattern to form an active layer of the active element including a semiconductor layer in a self-aligned manner, A method of manufacturing a liquid crystal display device, characterized in that a sidewall of the gate electrode is covered with an insulating film by anodic oxidation, and the light reflection plate is formed on an uneven region of the first substrate. 15. A light reflection plate, which is arranged in a matrix and also serves as a pixel electrode, and an active element for controlling a write charge to the pixel electrode for each pixel electrode, and for operating the active element. 1st with a predetermined wiring of
And a second substrate having a transparent electrode facing the pixel electrode, and a liquid crystal layer interposed between the first and second substrates. A flat area is formed in the area where the active element is formed, and the flat area is formed in the area where the active element is formed. Forming an active layer of the active element including a semiconductor layer on the region, covering a sidewall of the gate electrode with an insulating film by anodization, and forming the light reflection plate on an uneven region of the first substrate. A method for manufacturing a characteristic liquid crystal display device. 16. The first substrate, which is exposed from the back side of the first substrate by using the pattern of the gate electrode, and whose upper surface is covered with an insulating layer, a semiconductor layer, and a resist layer. 16. The method for manufacturing a liquid crystal display element according to claim 15, wherein the substrate of 1. is exposed from the back side, and the active layer of the active element including the semiconductor layer is formed in a self-aligned manner by using the resist pattern. 17. A light reflection plate, which is arranged in a matrix and also serves as a pixel electrode, and an active element for controlling a write charge to the pixel electrode for each pixel electrode, and for operating the active element. 1st with a predetermined wiring of
And a second substrate having a transparent electrode facing the pixel electrode, and a liquid crystal layer interposed between the first and second substrates. A signal wiring pattern in which the active element is patterned on the upper surface of the first substrate by forming unevenness of a predetermined height in at least a region corresponding to a region where the light reflection plate is formed on the surface of the first substrate. An insulating layer covers the upper part and is composed of a two-terminal type non-linear element formed on the side wall of the signal wiring. The non-linear element comprises an insulating layer and a resist layer on the upper part of the signal wiring patterned on the first substrate. The back surface of the first substrate, which is entirely covered, is exposed using a stripe-shaped mask that is orthogonal to the signal wiring to form a resist pattern that reflects the shape of the signal wiring and the mask shape. Is formed by a self-alignment process in which an insulating layer is patterned by using, and the signal wiring side wall exposed by patterning the insulating layer is covered with an insulating film by anodization, and the light reflection plate also serving as the pixel electrode is formed. A method for manufacturing a liquid crystal display element, which is characterized in that the liquid crystal display element is formed on an uneven region of a first substrate.