JPH09185078A - Liquid crystal element and production of this liquid element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence orientation defects, to prevent the deterioration of rubbing cloth and to facilitate the work to inject liquid crystals, etc. SOLUTION: Driving electrodes 23a,... (or 23b,...) are formed in a stripe form on the surface of a glass substrate 5a (or 5b) and insulating parts 27a,... (or 27b,...) are arranged in the spacings between these driving electrodes 23a (or 23b). A flat surface A is formed by the driving electrodes 23a (or 23b) and the insulating parts 27a (or 27b). An orientation control film 9a (or 9b) is formed on this surface A. Consequently, the surface of the oriented films 9a, 9b are nearly flattened and the execution of a uniform rubbing treatment is made possible. The occurrence of the orientation defects is thus prevented. Since the surface of the oriented films 9a, 9b are flat, the deterioration of the rubbing cloth is prevented and the inject resistance is lowered, by which the work to inject the liquid crystals is facilitated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal element that uses liquid crystal to display various information and a method for manufacturing the liquid crystal element.

[0002]

2. Description of the Related Art Conventionally, various liquid crystal elements have been proposed.

FIG. 1 is a view showing an example thereof, and the liquid crystal element P ₁ is provided with a pair of electrode substrates 1a and 1b. These electrode substrates 1a and 1b are bonded together by a sealing material 2, and a liquid crystal 3 is sandwiched between the substrate substrates.

By the way, these electrode substrates 1a, 1b
Have glass substrates 5a and 5b, respectively, and a large number of transparent electrodes 6a, ..., 6b, ... As drive electrodes are formed in stripes on the surfaces of the glass substrates 5a and 5b. The transparent electrodes 6a, ..., 6b, ... Are covered with insulating films 7a, 7b.
Alignment control films 9a and 9b having a thickness of 100 to 500 Å are formed on the surfaces of a and 7b. The surfaces of these alignment control films 9a and 9b are rubbed.

[0005] Transparent electrodes 6a described above, ..., 6b, ... predetermined signal is applied to the liquid crystal element P ₁ is configured to display various information.

[0006]

Since the above-mentioned transparent electrodes 6a, ..., 6b, ... Are formed to a thickness of about 1000 to 2000Å (see FIG. 2), the alignment control film 9 is formed.
There was some level difference on the surfaces of a and 9b. Therefore, there is a problem that the rubbing process cannot be performed uniformly, alignment defects are generated in the injected liquid crystal 3, and the display quality of the image deteriorates. In addition, the rubbing cloth is rubbed against the step by a predetermined force or more and easily deteriorates, it is difficult to control the uniformity of the rubbing cloth, and the workability of the rubbing process is deteriorated due to frequent replacement of the rubbing cloth. There was also. Further, there is a problem that the above-mentioned step becomes a resistance when the liquid crystal 3 is injected.

In the liquid crystal element, as shown in FIGS. 3 (a) and 3 (b), the transparent electrodes 6a, ..., 6b ,.
Metal electrodes 10a, ..., 10 with a thickness of about 3000 Å
There is a structure in which b, ... Are formed to avoid the delay of the voltage waveform. However, in such a structure, the step of the alignment control film is further increased, and the above-mentioned problem is particularly remarkable. .

Therefore, it is an object of the present invention to provide a liquid crystal element having good display quality by preventing the occurrence of alignment defects and a method for manufacturing the liquid crystal element.

Further, the present invention provides a liquid crystal device capable of reducing deterioration of the rubbing cloth, facilitating the uniformity control of the rubbing cloth, and improving the efficiency of the rubbing work, and a method of manufacturing the liquid crystal device. It is intended.

A further object of the present invention is to provide a liquid crystal element in which the operation of injecting liquid crystal is easy and a method of manufacturing the liquid crystal element.

Still another object of the present invention is to provide a liquid crystal element for preventing delay of voltage waveform and a method for manufacturing the liquid crystal element.

Another object of the present invention is to provide a liquid crystal element which prevents corrosion and disconnection of a metal electrode and a method of manufacturing the liquid crystal element.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and includes a pair of substrates that are spaced apart from each other, and a plurality of drive electrodes formed in stripes on each substrate. A liquid crystal disposed between the pair of substrates,
In the liquid crystal element having the above-mentioned, the insulating portion is embedded in the gap between the drive electrodes, and a substantially flat surface is formed by the drive electrode and the insulating portion.

In this case, each of the drive electrodes is constituted by a transparent electrode and a metal electrode arranged along the transparent electrode so as to come into contact with the transparent electrode, and the drive electrode and the insulating portion are formed. May form a substantially flat surface. Then, the transparent electrode, the metal electrode, and the insulating portion may all be formed on the surface of the substrate to have substantially the same thickness without a gap, so that a substantially flat surface may be formed. Further, the transparent electrode is formed on the surface of the substrate to be thicker than the metal electrode and has a recess on the surface, and the metal electrode has a bottom surface of the metal electrode and at least one side surface of the transparent electrode. It may be embedded in the recess so as to contact the electrode, and may form a substantially flat surface together with the transparent electrode. For example, the transparent electrode is formed in a substantially L-shaped cross section, the metal electrode is embedded in the transparent electrode, a drive electrode having a substantially rectangular cross section is formed together with the transparent electrode, and the drive electrode is embedded in the recess. The bottom surface and one side surface of the metal electrode may be in contact with the transparent electrode. Further, the transparent electrode is formed in a substantially U-shaped cross section, the metal electrode is embedded in the transparent electrode, a drive electrode having a substantially square cross section is formed together with the transparent electrode, and the drive electrode is embedded in the recess. The bottom surface and two side surfaces of the metal electrode may be in contact with the transparent electrode.

The transparent electrode may be formed of ITO containing an amorphous component or through the ITO. Further, it is preferable that the surface formed by the drive electrode and the insulating portion has a step of 20 nm or less.

On the other hand, in the method of manufacturing a liquid crystal element according to the present invention, a drive electrode forming step of forming drive electrodes in a stripe shape on a surface of a substrate and a pair of substrates on which the drive electrodes are formed are attached in a separated state. A substrate bonding step to match,
A liquid crystal injecting step of injecting liquid crystal into a gap between the pair of substrates, wherein an insulating part having a thickness substantially equal to that of the drive electrode is embedded in a gap between the drive electrodes. A drive electrode forming step, the drive electrode is patterned into stripes by etching with a resist in the drive electrode forming step, and insulation is performed in the insulating portion forming step without removing the resist. It is characterized in that the insulating portion is formed by forming a film and then peeling off the resist.

In this case, the drive electrode forming step includes a metal electrode forming step of forming a metal electrode in a stripe shape and a transparent electrode forming step of forming a transparent electrode by patterning the formed transparent electrode film in a stripe shape. And by performing these electrode forming steps, the drive electrode is formed by the metal electrode and the transparent electrode arranged so as to contact the metal electrode along the metal electrode. It is preferable to configure. Also,
In that case, in the metal electrode forming step, the metal electrode is patterned into stripes based on etching using the first resist, and in the transparent electrode forming step, the first resist is peeled off. The transparent electrode may be patterned into stripes based on etching using the second resist, and the insulating portion forming step may be performed without removing the second resist. . In these cases, in the metal electrode forming step, the metal electrode is directly formed on the surface of the substrate, and in the transparent electrode forming step, the transparent electrode has substantially the same thickness as the metal electrode. Directly on the surface of the substrate, in the step of forming the insulating portion, the insulating portion is formed directly on the surface of the substrate so as to have substantially the same thickness as the metal electrode and the transparent electrode, and The electrode, the metal electrode, and the insulating portion may form a substantially flat surface. Further, the transparent electrode forming step is performed before the metal electrode forming step and is performed after the first transparent electrode forming step of forming a transparent electrode film on the entire surface of the substrate, and after the metal electrode forming step. And a second transparent electrode forming step of forming a transparent electrode having a shape that is in contact with at least one side surface of the metal electrode,
In the metal electrode forming step, the metal electrode is formed on the surface of the transparent electrode film, and the metal electrode is arranged such that the bottom surface and at least one side surface of the metal electrode are in contact with the transparent electrode. You may do so. For example, in the first and second transparent electrode forming steps, the transparent electrode is formed into a substantially L-shaped cross section, the metal electrode is embedded in the transparent electrode, and the driving section has a substantially rectangular cross section. The electrode may be configured with the transparent electrode. Further, the transparent electrode is formed into a substantially U-shaped cross section by the first and second transparent electrode forming steps,
The metal electrode may be embedded in the transparent electrode to form a drive electrode having a substantially rectangular cross section together with the transparent electrode.

On the other hand, in the step of forming the metal electrode, the metal electrode may be formed by a sputtering method or vapor deposition. Further, it is preferable that the transparent electrode film is formed in the transparent electrode forming step under a low temperature condition where the first resist is not cured. Further, it is preferable that the insulating film is formed in the insulating portion forming step under a low temperature condition where the second resist is not cured. Furthermore, the first resist and the second resist may be positive resists.

Based on the above structure, an insulating portion is embedded in the gap between the drive electrodes, and a substantially flat surface is formed by the drive electrode and the insulating portion. Therefore, an alignment control film is formed on the surface. However, the surface of the orientation control film is also flat and a large step is not generated. Therefore, even if the rubbing treatment is performed by rubbing the rubbing cloth on the surface of the alignment control film, the rubbing treatment can be performed uniformly, the occurrence of alignment defects can be prevented, and a liquid crystal element having good display quality can be obtained. In addition, the deterioration of the rubbing cloth is reduced, and the uniformity of the rubbing cloth is easily managed. Further, it is not necessary to frequently replace the rubbing cloth, and it is possible to prevent the rubbing productivity from being lowered. Furthermore, the thickness of the liquid crystal becomes uniform, and the chromatographic effect due to microscopic changes in cell thickness is reduced. Further, the injection resistance of the liquid crystal is also lowered, the non-defective rate of the injection process is increased, or the injection time can be shortened.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. The same parts as those shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

First, a first embodiment of the present invention will be described with reference to FIG.

The liquid crystal element P _{2 according} to this embodiment is shown in FIG.
As shown in FIG. 3, a pair of electrode substrates 20a and 20b are provided, and a large number of spacer particles 21, ... Are interposed between these electrode substrates 20a and 20b to define the substrate gap. Further, a ferroelectric liquid crystal 22 having a fluorine-based chiral is injected into this substrate gap.

By the way, the driving electrodes 23 are formed on the surfaces of the glass substrates 5a and 5b constituting the electrode substrates 20a and 20b.
A large number of a, ..., 23b, ... Are formed in a stripe shape to form a simple matrix. Each one drive electrode 23b is composed of a transparent electrode 25b and a metal electrode 26b, and these electrodes 25b, 26b.
All have a substantially quadrangular cross section and are band-shaped, and are formed on the surface of the substrate 5b so that their side surfaces are in good contact with each other. The thickness of each of the electrodes 25b and 26b is set equal to 1500Å, and the surface of the drive electrode 23b formed by the electrodes 25b and 26b is set to be substantially flat.

The other drive electrodes 23a, ... Have the same structure as the drive electrodes 23b ,. That is, one drive electrode 23a is provided for each transparent electrode 2a as shown in FIG.
5a and a metal electrode 26a. These electrodes 25a, 26a each have a substantially quadrangular cross section and have a strip shape, and the substrate 5a is arranged so that its side surfaces are in good contact with each other.
Is formed on the surface. In addition, these electrodes 25a,
The thickness of 26a is set equal to 1500Å, and the surface of the drive electrode 23a formed by these electrodes 25a and 26a is set to be substantially flat.

The transparent electrodes 25a, ..., 25b ,.
Are preferably formed by annealing amorphous ITO as necessary. Further, the metal electrodes 26a, ..., 26b ,.
It has a three-layer structure of SiCu / MoTa alloy, and the thickness of each layer is 300Å / 1000Å / 200Å.

On the other hand, an insulating portion 27a having a thickness of 1600Å is buried in the gap between the adjacent drive electrodes 23a, 23a (see FIG. 5 (i)), and the drive electrodes 23b, 23b.
Insulating portions 27b having a thickness of 1600Å are embedded in the mutual gaps (see FIG. 4). In addition, these insulating parts 27
a and 27b are made of SiN. By forming the insulating portions 27a, ..., 27b, ..., On the surface of the glass substrate 5a, the transparent electrodes 25a ,.
, And insulating portions 27a, ... Are arranged without a gap, and the transparent electrodes 25b, ..., Metal electrodes 26b, ..., and insulating portions 27b, .. are arranged without a gap on the surface of the other glass substrate 5b. .

That is, in the present embodiment, the surfaces of the drive electrodes 23a, ..., 23b, ... Are almost flat,
And, since the drive electrodes 23a, ..., 23b, ... Are embedded in the mutual gaps, the insulating electrodes 27a ,.
The transparent electrodes 25a, ..., The metal electrodes 26a, .. and the insulating portions 27a, ..... Form a substantially flat surface A having a step of 20 nm or less, and the other transparent electrode 25b ,.
6b, ..., And the insulating parts 27b, .. will form a substantially flat surface A having a step of 20 nm or less.

The surfaces A and A described above have a thickness of 20.
Alignment control films 9a and 9b of 0Å are formed.

Next, a method of manufacturing the liquid crystal element P ₂ will be described.
A description will be given with reference to FIGS.

The method for manufacturing a liquid crystal element according to the present embodiment has a drive electrode forming step, an insulating portion forming step, an alignment control film forming step, a substrate bonding step, and a liquid crystal injecting step. Hereinafter, each will be described. (Drive Electrode Forming Step) In the present embodiment, the drive electrode forming step includes the metal electrode forming step of forming the metal electrodes 26a, ..., 26b, ... and the transparent electrodes 25a ,.
and a transparent electrode forming step of forming b, ...
Then, in these steps, a thin film made of a predetermined material is formed using a sputtering method or the like, and exposure / etching is performed using a resist to remove the metal electrode 26a,
, 26b, ... And transparent electrodes 25a, ..., 25b ,. Hereinafter, the details of each step of the one electrode substrate 20a will be described. (Metal electrode forming step) First, MoTa alloy / AlSiC
A three-layer metal thin film 30 made of a u / MoTa alloy is formed on the surface of the glass substrate 5a by a sputtering method or vapor deposition (see FIG. 5 (a)). The thickness of the metal thin film 30 is 1500Å.

Next, stripe-shaped positive resists (first resists) 31, ... Are formed on the surface of the metal thin film 30 at a predetermined pitch (see FIG. 3B). The positive resist 31, ... Is patterned by uniformly applying the resist on the entire surface of the metal thin film 30, exposing it using an exposure mask, and further etching.

Further, the metal thin film 30 is subjected to patterning by exposure and etching to remove the metal thin film 30 in a portion not covered with the positive type resists 31, .... As a result, the metal electrodes 26a, ... Formed in a stripe shape directly on the surface of the glass substrate 5a are obtained (see FIG.
(c)). (Transparent Electrode Forming Step) Next, the amorphous IT is formed by a sputtering method under the condition that the positive resists 31, ... Are not peeled off and the positive resists 31 ,.
An O thin film (a-ITO, transparent electrode film) 32 is formed (see FIG. 3D). The film forming conditions were as follows. That is, the apparatus; ILC3949 target manufactured by Nichiden Anelva; ITO target manufactured by Mitsui Kinzoku; transport speed; 220 mm / min pressure; 2 × 10 ⁻³ Torr O ₂ flow rate; 0.5 sccm Ar flow rate; 150 sccm set temperature; room temperature discharge power; 2.0 kW film thickness; 1600 Å The ITO thin film 32 formed as described above peels off the positive resist 31, ... And lifts off, and further positive resist (second resist) 33 ,. Based on the etching used, the transparent electrodes 25a, ... Are formed by patterning in stripes.

That is, by performing lift-off, the positive type resists 31, ... And the ITO thin film 32 in the portions of the resists 31, ... Are removed (see FIG. 8E).

Further, the other positive type resist 33, ...
Is formed in a stripe shape so as to cover a part of the ITO thin film 32 and the metal electrodes 26a, ... As shown in FIG. 6 (f), the positive resist 33 is etched by using the resist 33 ,. Then, remove the exposed part that is not covered with, (See (g) in the figure).

As a result, the stripe-shaped transparent electrode 25 is formed.
a, ... Is obtained.

In this embodiment, the amorphous I
The etching characteristics of the TO thin film 32 are close to the metal etching characteristics. Further, the thickness of the positive resist 33, ... Is set to 2 μm.

Further, in this process, the film forming conditions are precisely controlled so that the thickness of the ITO thin film 32 is 1600 Å, which is 100 Å thicker than the metal electrodes 26a, .... This is because the film thickness of the transparent electrodes 25a, ... Is reduced by about 100Å after annealing in the subsequent process, so that the thickness of the transparent electrodes 25a ,.
This is for making the thicknesses of 6a, ...

Even if the transparent electrodes 25a, ... Are formed,
The next insulating portion forming step is performed without peeling off the positive type resists 33, .... (Insulating portion forming step) In this step, the metal electrode 26
.. and transparent electrodes 25a, ... Insulating portions 27a, ..

That is, the insulating thin film 35 made of SiN is formed by the sputtering method in a state where the resists 33, ... Are not peeled off (see FIG. 6 (h)). In the sputtering of the insulating thin film 35, Si was used as the target material, DC sputtering was used, and nitrogen gas was used as the atmosphere gas. Further, the film formation conditions were set to a low temperature without heating the substrate so that the positive resists 33 ,.

Further, lift-off was carried out to remove the positive type resists 33, ... And the insulating thin film 35 in the resists 33, .. (See FIG. 1 (i)). As a result, the insulating portions 27a, ... Are directly formed on the surface of the substrate 5a.

The formation of the insulating portions 27a, ...
It may be performed once, or may be divided into two times. Then, when the insulating portions 27a, ... Are formed twice, the heating temperature of the substrate can be suppressed, and adverse effects on the transparent electrodes and the like can be suppressed. (Alignment control film forming step) Then, these transparent electrodes 25
The orientation control film 9a (LQ1802 manufactured by Hitachi Chemical Co., Ltd.) having a thickness of 200 Å was formed on the surfaces A of the metal electrodes 26a, ..., And the insulating electrodes 27a ,.

Through the above steps, one electrode substrate 20a
However, the other electrode substrate 20 is formed by the same process.
b is also manufactured. (Substrate bonding step) Next, spacer particles 21, ... Are sprinkled on the surface of either one of the electrode substrates 20a or 20b, the sealing material 2 is applied, and the two electrode substrates 20a, 20b.
Stick b together. (Liquid Crystal Injection Step) After that, the chiral smectic liquid crystal 22 having ferroelectricity is injected into the gap between the pair of substrates 5a and 5b.

Next, the effect of this embodiment will be described.

According to this embodiment, the metal electrodes 26a,
, 26b, ... Are arranged along the transparent electrodes 25a, .., 25b, ... To transmit the drive signal, so that the problem of voltage waveform delay is solved.

If the substrate temperature at the time of forming the metal electrodes 26a, ..., 26b, ... Is high, the crystallinity is good and the line resistance is low, but there are problems such as the generation of precipitates and the hardening of the resist. However, in the present embodiment, by setting the substrate temperature to about 120 ° C., these problems are solved and the line resistance is reduced.

Further, transparent electrodes 25a, ..., Metal electrodes 26
, and the insulating portions 27a, ... Form a flat surface A, and the other transparent electrodes 25b ,.
, And the insulating portions 27b, ... form a flat surface A, so that the orientation control films 9a, 9a formed on these surfaces,
The surface of 9b is also flat, and a large step does not occur. In addition, when the present inventor actually measured with a stylus type roughness meter, it was found that PV
It was confirmed by (Peak to Valley) that a substrate of 120 Å was obtained.

Therefore, the following effects can be obtained.

That is, since no large step is formed on the surfaces of the orientation control films 9a and 9b, the rubbing process can be performed uniformly. As a result, alignment defects are hardly generated in the injected liquid crystal 22, and a liquid crystal element having good display quality can be obtained.

Further, since a large step is not formed on the surfaces of the orientation control films 9a and 9b, the rubbing cloth is less deteriorated and the uniformity of the rubbing cloth is easily controlled. And
It is not necessary to frequently change the rubbing cloth, and the workability of the rubbing process is improved accordingly.

Furthermore, since no large step is formed on the surfaces of the orientation control films 9a and 9b, the thickness of the liquid crystal layer becomes uniform, the chromatographic effect due to the micro change of the cell thickness decreases, and the injection resistance of the liquid crystal 22 also decreases. In addition, the non-defective rate of the injection process can be increased, or the injection time can be shortened.

Next, another embodiment of the present invention will be described with reference to FIGS. 6 (a) to 6 (j).

The liquid crystal element according to the present embodiment is shown in FIG.
2 are provided in the gap between the pair of electrode substrates 50, 50, and a large number of spacer particles (not shown) and a chiral smectic exhibiting ferroelectricity are provided in the gap between the pair of electrode substrates 50, 50. A liquid crystal (also not shown) is arranged.

A large number of drive electrodes 52, ... Are formed in stripes on the surface of the glass substrate 51 which constitutes the electrode substrate 50. Each drive electrode 52 is formed with one transparent electrode 53. It is composed of one metal electrode 55. Of these, the transparent electrode 53 is formed on the surface of the glass substrate 51 so as to have a substantially L-shaped cross section.
By the thick portion 53a and the thin portion 53b, the thick portion 53a
A concave portion is formed laterally (that is, above the thin portion 53b). The thickness of the thick portion 53a is 1600Å
Then, the thickness of the thin portion 53b is set to 200Å.
Further, the transparent electrodes 53, ...
Preferably, it is formed by annealing amorphous ITO as needed.

Further, the metal electrode 55 is embedded in the recess of the transparent electrode 53, and one side surface and the bottom surface thereof are transparent electrode 53.
And the transparent electrode 53 constitutes a drive electrode 52 having a substantially rectangular cross section. Further, the metal electrodes 55, ... Have a three-layer structure of MoTa alloy / AlSiCu / MoTa alloy, and the thickness of each layer is 100Å / 90.
It is specified as 0Å / 400Å and the total thickness is 1400Å. In the present embodiment, the thickness difference between the thick portion 53a and the thin portion 53b of the transparent electrode 53 is 14
Since it is 00Å, a substantially flat surface B is formed by the transparent electrode 53 and the metal electrode 55.

On the other hand, in the gap between the drive electrodes 52, ...
Insulating portion 56 made of SiO _X, ... are embedded, transparent electrode 53 on the surface of the glass substrate 51, ..., the metal electrode 5
5, and the insulating portions 56, ... Are arranged without a gap. Further, the thickness of the insulating portions 56, ...
The thickness is set to 1600 Å so as to be equal to the thickness of 2, ..., And the substantially flat surface B having a step of 20 nm or less is formed by the insulating portions 56 ,. Further, on this surface B, an orientation control film (not shown) having a thickness of 200Å is formed.

Next, the manufacturing method of the liquid crystal element will be described with reference to FIG.
Explanation will be given along (a) to (j).

The method of manufacturing a liquid crystal element according to the present embodiment has a drive electrode forming step, an insulating portion forming step, an alignment control film forming step, a substrate bonding step, and a liquid crystal injecting step. Hereinafter, each step will be described. (Drive Electrode Forming Step) In the present embodiment, the drive electrode forming step is (1) a thin portion forming step of forming the amorphous ITO thin film 60 on the entire surface of the substrate 51 (first transparent electrode forming step) (2) Amorphous IT is performed after the thin portion forming step.
A metal electrode forming step of forming the metal electrodes 55, ... On the surface of the O thin film 60 (3) A transparent electrode having a shape to be contacted with one side surface of the metal electrodes 55 ,. And a thick portion forming step (second transparent electrode forming step) to form a transparent electrode 53 having a substantially L-shaped cross section by the thin portion forming step and the thick portion forming step. To be done. That is, in the present embodiment, the transparent electrode forming step is
It includes a thin portion forming step and a thick portion forming step. (Thin Section Forming Step) First, an amorphous ITO thin film (transparent electrode film) 60 is formed on the surface of the glass substrate 51 by a sputtering method (see FIG. 3A). The film forming conditions of the apparatus, the target, and the like were almost the same as those in the above-described embodiment, except that the discharge power was 0.3 kW. And
The thickness of the amorphous ITO thin film 60 was set to 200Å. (Metal Electrode Forming Step) Next, a three-layer metal thin film 61 composed of MoTa alloy / AlSiCu / MoTa alloy is formed on the surface of the amorphous ITO thin film 60 by sputtering or vapor deposition. It is formed (see Figure (b)). The thickness of each layer is 100Å / 90
0Å / 400Å, total thickness of the metal thin film 61 is 1400Å
And

Then, on the surface of the metal thin film 61, a stripe-shaped positive resist (first resist) 62,
Are formed at a predetermined pitch (see (c) in the figure). Further, exposure is performed and etching is performed using a mixed acid of acetic acid, phosphoric acid and nitric acid to remove the metal thin film 61 in the portion not covered with the positive type resists 62, ... (See FIG. 3D). As a result, the metal electrodes 55, ... Formed in stripes on the surface of the amorphous ITO thin film 60 are obtained. (Thick portion forming step) Thereafter, an amorphous ITO thin film 63 having a thickness of 1500 Å is formed by a sputtering method under the condition that the resists 62, ... Are not peeled off and the resists 62 ,. (See Figure (e)).

The ITO thin film 63 formed as described above
Are removed by lift-off by peeling off the resists 62, ... (Refer to (f) in the same figure), and etching is performed using a positive type resist (second resist) 65 ,. (see (h)), the transparent electrodes 53, ... Are formed by patterning in stripes.

That is, by performing lift-off, the positive type resists 62, ... And the ITO thin film 63 on the resists 62, ... Are removed (see FIG. 6 (f)).

Further, another positive type resist 65, ...
As shown in FIG. 6G, the ITO thin film 63 is formed at a constant pitch so as to cover a part thereof and the metal electrodes 55, .... Then, after the exposure, an amorphous IT is formed by hydroiodic acid.
By etching the O thin film 63, a positive resist 65, ...
Remove the part that is not covered with and is exposed (see (h) in the figure). As a result, stripe-shaped transparent electrodes 53, ... Are formed.

In this process, the film forming conditions are precisely controlled to set the thickness of the ITO thin film 63 to 1500 Å, and the transparent electrodes 53, ... 10 from the surface of the metal electrodes 55a ,.
It is designed to project by 0Å. This is the transparent electrode 5
Since the film thicknesses of 3, ... Are reduced by about 100Å after annealing in the subsequent process, the transparent electrodes 53 ,.
This is to form a substantially flat surface with the surfaces of the metal electrodes 55, ....

Even if the transparent electrodes 53, ... Are formed, the positive resists 65, .. (Insulating part forming step) Next, by a sputtering method,
An insulating thin film 66 made of SiO _x is formed to a thickness of 1600 Å (see (i) in the figure).

When the insulating thin film 66 is formed, the substrate is not heated and the film forming condition is set to low temperature.
The resists 65, ... Are prevented from hardening.

Further, lift-off was carried out to remove the positive type resists 65, ... And the insulating thin film 66 in the resists 65 ,. As a result, the insulating portions 56, ... Are directly formed on the surface of the substrate 51. (Alignment control film forming step) And these transparent electrodes 5
3, ..., Metal electrodes 55, ..., And the surface B of the insulating portion 56, .. A TaO sputtered film is formed to a thickness of 900 Å, and a TiSiO _x spin coat film is formed to a thickness of 500 Å, and further oriented. A control film (LQ1802 manufactured by Hitachi Chemical Co., Ltd.) was formed to a thickness of 200Å and rubbed with a nylon cloth. Thereby, the electrode substrate 50 is formed. (Substrate Bonding Step) Next, spacer particles are dispersed on the surface of the electrode substrate 50, a sealing material is applied, and the two electrode substrates 50, 50 are bonded together. (Liquid Crystal Injection Step) After that, ferroelectric liquid crystal is injected into the gap between the pair of substrates 50, 50.

Next, the effect of the present embodiment will be described.

According to the present embodiment, each transparent electrode 53,
The cross-sectional shape of ... Is substantially L-shaped, and each metal electrode 55 ,.
However, since one side surface and the bottom surface are arranged so as to contact the respective transparent electrodes 53, ..., The contact area between the respective metal electrodes 55, ... And the respective transparent electrodes 53 ,. The contact resistance of the electrode is reduced, and the display quality of the liquid crystal element is improved.

Further, according to the present embodiment, the same effect as that of the above-mentioned embodiments can be obtained.

That is, according to the present embodiment, since the metal electrodes 55, ... Are arranged along the transparent electrodes 53, ... And transmit the drive signal, the problem of the delay of the voltage waveform is solved.

If the substrate temperature at the time of depositing the metal electrodes 55, ... Is high, the crystallinity is good and the line resistance is low, but there are problems such as the generation of precipitates and the effect of the resist. In this mode, the substrate resistance is set to about 120 ° C. to solve these problems and reduce the line resistance.

Further, the transparent electrodes 53, ..., The metal electrodes 55,
.. and the insulating portions 56, ... Form a flat surface B, so that the surface of the orientation control film formed on these surfaces is also flat and a large step is not generated. In addition, when the present inventor actually measured with a stylus type roughness meter, it was 180 Å in PV.

Therefore, the following effects can be obtained.

That is, since a large step is not formed on the surface of the orientation control film, the rubbing process can be performed uniformly.
As a result, almost no alignment defects occur in the injected liquid crystal, and a liquid crystal element having good display quality can be obtained.

Further, since a large step is not formed on the surface of the orientation control film, deterioration of the rubbing cloth is reduced and the uniformity of the rubbing cloth is easily controlled. Further, it is not necessary to frequently change the rubbing cloth, and the workability of the rubbing process is improved accordingly.

Further, since a large step is not formed on the surface of the orientation control film, the thickness of the liquid crystal layer becomes uniform, the chromatographic effect due to the micro change of the cell thickness is reduced, the injection resistance of the liquid crystal is lowered, and the injection is performed. The non-defective rate of the process can be increased or the injection time can be shortened.

Next, another embodiment of the present invention will be described with reference to FIGS. 7 (a) to 7 (j).

The liquid crystal element according to the present embodiment is shown in FIG.
2 are provided, and a large number of spacer particles (not shown) and a chiral smectic exhibiting ferroelectricity are provided in the gap between the pair of electrode substrates 70, 70, as in the above-described embodiment. A liquid crystal (also not shown) is arranged.

A large number of drive electrodes 72, ... Are formed in stripes on the surface of the glass substrate 71 that constitutes the electrode substrate 70. Each drive electrode 72 and one transparent electrode 73. It is composed of one metal electrode 75. Of these, the transparent electrode 73 is formed on the surface of the glass substrate 71 so that the cross-sectional shape is a substantially U shape.
It has a recess on the surface. The transparent electrodes 73, ...
Similar to the above-described embodiment, it is formed by annealing amorphous ITO as needed.

Further, the metal electrode 75 is embedded in the recess of the transparent electrode 73, two side surfaces and the bottom surface of which are in contact with the transparent electrode 73, and together with the transparent electrode 73, the drive electrode 72 having a substantially rectangular cross section is formed. doing. And the metal electrode 75
The transparent electrode 73 and the transparent electrode 73 form a substantially flat surface.

On the other hand, an insulating portion 76 is embedded in the gap between the drive electrodes 72, 72, and the drive electrodes 72, ... And the insulating portions 76 ,. It will be.

The transparent electrodes 73, ..., The metal electrodes 75,
, And insulating portions 76, ... Are formed to a thickness such that they form a substantially flat surface C, and an orientation control film (not shown) is formed on the surface C.

In the present invention, the above-mentioned formation of the electrode substrate can be applied to a color liquid crystal display element. That is, after forming the color filter film of each color of R, G, B and the like and the flattening layer thereof on the substrate, the above-mentioned transparent electrode and insulating layer can be formed.

Next, the manufacturing method of the liquid crystal element will be described with reference to FIG.
Explanation will be given along (a) to (j).

The method of manufacturing the liquid crystal element in the present embodiment is almost the same as that shown in FIG. 6, and includes a thin portion forming step (first transparent electrode forming step), a metal electrode forming step, and a thick wall forming step. And a drive electrode forming step including a part forming step (second transparent electrode forming step), and an insulating part forming step, an alignment control film forming step, a substrate bonding step, and a liquid crystal injecting step. And have. Further, the transparent electrode forming step is constituted by the thin portion forming step and the thick portion forming step.

However, in this embodiment, the positive resist (second resist) 6 is used in the thick portion forming step.
The position where 5, ... Is formed is different from that of the above-described embodiment, each positive resist 65 ,.
, And the amorphous ITO thin film 6 on both sides of each metal electrode 75.
3 and 3 are arranged so as to cover them. As a result, the transparent electrodes 73, ... Are formed in a substantially U-shaped cross section.

Next, the effect of this embodiment will be described.

Generally, even if the etching characteristic of the amorphous ITO thin film is brought close to the metal etching characteristic, metal corrosion occurs in the Al alloy or the like in the step of etching the amorphous ITO thin film due to pattern defects of the resist, dust, and the like. However, there is a problem in that the internal resistance of the metal electrode increases, and in the worst case, the metal electrode is disconnected.

However, according to the present embodiment, since the metal electrodes 75, ... Are embedded inside the transparent electrodes 73, .., the metal electrodes 75 ,. is there.

Further, according to the present embodiment, the transparent electrode 7
The cross-sectional shape of 3, ... Is substantially U-shaped, and each metal electrode 75,
, Are arranged so that the both side surfaces and the bottom surface thereof are in contact with the respective transparent electrodes 73, ... Therefore, the contact area between the respective metal electrodes 75 ,. The contact resistance of these electrodes is reduced, and the display quality of the liquid crystal element is improved.

Further, also in this embodiment, the same effect as that of the other embodiments described above can be obtained.

That is, according to the present embodiment, since the metal electrodes 75, ... Are arranged along the transparent electrodes 73, ... And transmit the drive signal, the problem of voltage waveform delay is solved.

If the substrate temperature at the time of forming the metal electrodes 75, ... Is high, the crystallinity is good and the line resistance is lowered, but on the other hand, there are problems such as the generation of precipitates and the hardening of the resist. In this mode, the substrate resistance is set to about 120 ° C. to solve these problems and reduce the line resistance.

Further, transparent electrodes 73, ..., Metal electrodes 75,
.. and the insulating portions 76, ... Form a flat surface C, so that the surface of the orientation control film formed on these surfaces is also flat and a large step is not generated. Therefore, the following effects can be obtained.

That is, since a large step is not formed on the surface of the orientation control film, the rubbing process can be performed uniformly.
As a result, almost no alignment defects occur in the injected liquid crystal, and a liquid crystal element having good display quality can be obtained.

Further, since a large step is not formed on the surface of the orientation control film, deterioration of the rubbing cloth is reduced and the uniformity of the rubbing cloth is easily controlled. Further, it is not necessary to frequently change the rubbing cloth, and the workability of the rubbing process is improved accordingly.

Furthermore, since the surface of the orientation control film does not have a large step, the thickness of the liquid crystal layer becomes uniform, the chromatographic effect due to microscopic changes in cell thickness is reduced, and the injection resistance of the liquid crystal is also lowered to perform injection. The non-defective rate of the process can be increased or the injection time can be shortened.

In each of the above embodiments,
Although the present invention is applied to a ferroelectric liquid crystal that obtains orientation by rubbing with high surface sensitivity, the invention is not limited to this and may be applied to TN, STN, and TFT. Further, it may be applied to a technique of obtaining an orientation by a surface impregnation method that imparts anisotropy other than rubbing, such as oblique vapor deposition, and even in that case, uniform film formation, ease of liquid crystal injection, Effects such as uniformity of cell thickness can be obtained.

[0098]

As described above, according to the liquid crystal element of the present invention, a substantially flat surface is formed by the drive electrode and the insulating portion. Therefore, even if an alignment control film is formed on that surface,
Similarly, the surface of the orientation control film is flat and no large step is generated. Therefore, even if the rubbing treatment is performed by rubbing the rubbing cloth on the surface of the alignment control film, the rubbing treatment can be performed uniformly, the occurrence of alignment defects can be prevented, and a liquid crystal element having good display quality can be obtained. In addition, the deterioration of the rubbing cloth is reduced, and the uniformity of the rubbing cloth is easily managed. Further, it is not necessary to frequently replace the rubbing cloth, and it is possible to prevent the rubbing productivity from being lowered. Furthermore, the thickness of the liquid crystal becomes uniform, and the chromatographic effect due to microscopic changes in cell thickness is reduced. Further, the injection resistance of the liquid crystal is also lowered, the non-defective rate of the injection process is increased, or the injection time can be shortened.

Further, when each drive electrode is composed of a transparent electrode and a metal electrode arranged along the transparent electrode so as to contact the transparent electrode, the delay of the voltage waveform is eliminated. .

Further, when the drive electrode is formed by embedding the metal electrode in the recess of the transparent electrode, the contact area between the transparent electrode and the metal electrode can be increased to reduce the contact resistance, and the display quality of the liquid crystal element is improved. The effect is improved.

Furthermore, when the transparent electrode is formed in a substantially U-shaped cross section and the drive electrode is formed by embedding the metal electrode in the recess formed by the U-shaped cross section, the bottom surface of the metal electrode Further, the two side surfaces contact the transparent electrode, and the contact area between the transparent electrode and the metal electrode can be further increased. Further, metal corrosion or disconnection is unlikely to occur on the metal electrode.

[Brief description of the drawings]

FIG. 1 is a sectional view illustrating a general structure of a liquid crystal element.

FIG. 2 is a detailed cross-sectional view for explaining the shape of a transparent electrode.

FIG. 3 is a detailed cross-sectional view for explaining another structural example in which a metal electrode is arranged, (a) shows a metal electrode formed only on the surface of a transparent electrode, and (b) shows a metal electrode. The figure which shows what is formed over a transparent electrode and a glass substrate.

FIG. 4 is a sectional view for explaining the structure of the liquid crystal element according to the present invention.

FIG. 5 is a diagram for explaining a method of manufacturing a liquid crystal element according to the present invention, particularly a method of manufacturing an electrode substrate.

FIG. 6 is a diagram for explaining a method for manufacturing a liquid crystal element according to the present invention, particularly a method for manufacturing an electrode substrate.

FIG. 7 is a diagram for explaining a method for manufacturing a liquid crystal element according to the present invention, particularly a method for manufacturing an electrode substrate.

[Explanation of symbols]

5a, 5b Glass substrate 22 Chiral smectic liquid crystal (liquid crystal) 23a, ..., 23b, ... Driving electrode 25a, ..., 25b, ... Transparent electrode 26a, ..., 26b, ... Metal electrode 27a ,. Insulating portion 31, Positive resist (first resist) 32 Amorphous ITO thin film (transparent electrode film) 33, Positive resist (second resist) 35 Insulating thin film (insulating film) 51 Glass substrate 52, Drive electrode 53, transparent electrode 55, metal electrode 56, insulating part 62, positive resist (first resist) 63 amorphous ITO thin film (transparent electrode film) 65, positive resist (second resist) Resist) 66 insulating thin film (insulating film) 71 glass substrate 72, ... drive electrode 73, ... transparent electrode 75, ... metal electrode 76, ... insulation part A flat surface B flat surface C Flat surface P ₂ Liquid crystal element

Claims (19)

[Claims] 1. A liquid crystal device comprising: a pair of substrates arranged apart from each other; a plurality of drive electrodes formed in stripes on each substrate; and a liquid crystal arranged between the pair of substrates. A liquid crystal element, wherein an insulating portion is embedded in a gap between the drive electrodes, and a substantially flat surface is formed by the drive electrode and the insulating portion. 2. Each of the drive electrodes is configured by a transparent electrode and a metal electrode arranged along the transparent electrode so as to be in contact with the transparent electrode, and the drive electrode and the insulating portion are provided. The liquid crystal element according to claim 1, wherein a substantially flat surface is formed. 3. The transparent electrode, the metal electrode, and the insulating portion are all formed on the surface of the substrate to have substantially the same thickness without a gap, so that a substantially flat surface is formed. The liquid crystal element according to claim 2. 4. The transparent electrode is formed on the surface of the substrate to be thicker than the metal electrode, and has a recess on the surface, and the metal electrode has a bottom surface and at least one side surface of the metal electrode. 3. The liquid crystal element according to claim 2, wherein the liquid crystal element is embedded in the recess so as to contact the transparent electrode, and forms a substantially flat surface together with the transparent electrode. 5. The transparent electrode is formed to have a substantially L-shaped cross section, the metal electrode is embedded in the transparent electrode to form a drive electrode having a substantially rectangular cross section together with the transparent electrode, and the recessed portion. The liquid crystal element according to claim 4, wherein a bottom surface and one side surface of the metal electrode embedded in the transparent electrode are in contact with the transparent electrode. 6. The transparent electrode is formed in a substantially U-shaped cross section, the metal electrode is embedded in the transparent electrode to form a drive electrode having a substantially rectangular cross section together with the transparent electrode, and the recessed portion. 5. The liquid crystal element according to claim 4, wherein the bottom surface and the two side surfaces of the metal electrode embedded in are in contact with the transparent electrode. 7. The IT in which the transparent electrode contains an amorphous component.
7. The liquid crystal device according to claim 2, wherein the liquid crystal device is formed of O. 7. 8. The liquid crystal element according to claim 1, wherein a surface formed by the drive electrode and the insulating portion has a step difference of 20 nm or less. 9. A drive electrode forming step of forming drive electrodes in a stripe shape on the surface of a substrate, a substrate attaching step of attaching a pair of substrates on which the drive electrodes are formed in a separated state, and a pair of these substrates. A liquid crystal injecting step of injecting liquid crystal into the gap between the driving electrodes, the method comprising: In the drive electrode forming step, the drive electrode is patterned into stripes based on etching with a resist, and in the insulating portion forming step, an insulating film is formed without removing the resist. Then, the insulating portion is formed by peeling off the resist, and the method for producing a liquid crystal element. 10. The drive electrode forming step includes a metal electrode forming step of forming a metal electrode in a stripe shape, and a transparent electrode forming step of forming a transparent electrode by patterning the formed transparent electrode film in a stripe shape. Consists of,
And, by carrying out these electrode forming steps, the drive electrode is constituted by the metal electrode and the transparent electrode arranged so as to come into contact with the metal electrode along the metal electrode. 10. The method for manufacturing a liquid crystal element according to claim 9, which is characterized in that. 11. In the metal electrode forming step, the metal electrode is patterned into stripes based on etching using a first resist, and in the transparent electrode forming step, the first resist is peeled off. In addition, the transparent electrode is patterned into a stripe shape based on etching using the second resist, and the insulating portion forming step is performed in a state where the second resist is not peeled off. The method for manufacturing a liquid crystal element according to claim 10. 12. The metal electrode is formed directly on the surface of the substrate in the metal electrode forming step, and the transparent electrode is formed to have a thickness substantially equal to that of the metal electrode in the transparent electrode forming step. Directly formed on the surface of the substrate, in the insulating portion forming step, the insulating portion is directly formed on the surface of the substrate so as to have substantially the same thickness as the metal electrode and the transparent electrode, and the transparent electrode, The method for manufacturing a liquid crystal element according to claim 10 or 11, wherein the metal electrode and the insulating portion form a substantially flat surface. 13. The first transparent electrode forming step of forming the transparent electrode film on the entire surface of the substrate by performing the transparent electrode forming step before the metal electrode forming step, and the metal electrode forming step. And a second transparent electrode forming step of forming a transparent electrode having a shape such that the transparent electrode is in contact with at least one side surface of the metal electrode. The metal electrode is formed on the surface, and the metal electrode is arranged so that the bottom surface and at least one side surface of the metal electrode are in contact with the transparent electrode. Manufacturing method of liquid crystal element of. 14. The transparent electrode is formed into a substantially L-shaped cross section by the first and second transparent electrode forming steps, and the metal electrode is embedded in the transparent electrode to have a substantially cross section. 14. The method for manufacturing a liquid crystal element according to claim 13, wherein a rectangular drive electrode is formed together with the transparent electrode. 15. The transparent electrode is formed into a substantially U-shaped cross section by the first and second transparent electrode forming steps, and the metal electrode is embedded in the transparent electrode to have a substantially cross section. 14. The method for manufacturing a liquid crystal element according to claim 13, wherein a rectangular drive electrode is formed together with the transparent electrode. 16. The method for manufacturing a liquid crystal element according to claim 10, wherein the metal electrode is formed by a sputtering method or vapor deposition in the metal electrode forming step. 17. The liquid crystal according to claim 11, wherein the transparent electrode film is formed in the transparent electrode forming step under a low temperature condition where the first resist is not cured. Device manufacturing method. 18. The liquid crystal device according to claim 11, wherein the insulating film is formed in the insulating portion forming step under a low temperature condition in which the second resist is not cured. Manufacturing method. 19. The method for manufacturing a liquid crystal device according to claim 11, wherein the first resist and the second resist are positive resists.