JP2883208B2 - Liquid crystal display device and manufacturing method thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a liquid crystal display device having a MIM element having a metal-insulator-metal structure or a metal-insulator-transparent conductor structure, and a method of manufacturing the liquid crystal display device. .

BACKGROUND ART Liquid crystal display devices have been put into practical use, and at present, an active matrix type liquid crystal display device capable of obtaining high-quality image quality is becoming mainstream.

Here, the active matrix method means a thin film transistor (TFT), a diode, or a metal-insulator-metal or metal-insulator-transparent conductor three-layer structure for each liquid crystal display electrode that is a display electrode. Insulator
A non-linear resistance element having a Metal (hereinafter referred to as MIM) structure as a switching element.

The MIM element is generally, Ta-Ta ₂ O ₅ -Cr or Ta
It is composed of -Ta ₂ O ₅ -ITO structure. Here, Ta means a tantalum film, Ta ₂ O ₅ means a tantalum oxide film, Cr means a chromium film, and ITO means an indium tin oxide film.

A liquid crystal display device using a MIM element performs display by using a non-linear voltage-current characteristic of the MIM element to switch a liquid crystal layer arranged in series with the MIM element.

The structure of a conventional liquid crystal display panel having non-linear resistance element of the Ta-Ta ₂ O ₅ -ITO structure will be described with reference to Figure 32 from Figure 29.

The MIM element is connected to the first substrate 1 as shown in FIG.
Tantalum (Ta) as lower electrode 103 formed on 02
Film, a tantalum oxide (Ta ₂ O ₅ ) film as an insulating film 104 formed thereon, and an upper electrode 105 further formed thereon
And a transparent conductive film made of an indium tin oxide (ITO) film as a non-linear resistance element portion.

Further, the MIM element has a display electrode 106 made of an indium tin oxide film. Then, a data signal depending on display contents is applied to the display electrode 106 via the non-linear resistance element portion, via the signal electrode 10 made of a tantalum film and a tantalum oxide film.
Apply by 7.

This liquid crystal display device includes a first substrate 102 on which a non-linear resistance element portion is formed, and a counter electrode 110 (shown by a virtual line in FIG. 30) formed so as to face a display electrode 106 formed on the first substrate 102. (FIG. 29).

Then, an alignment process is performed on the first substrate 102 and the second substrate 109. After that, the first substrate 102 is
And the second substrate 109 are bonded with a certain gap therebetween,
Liquid crystal is sealed in the gap to constitute a liquid crystal display device. The inner area shown by a virtual line 118 in FIG. 29 and a solid line 118 in FIG. 30 is a display area.

However, the liquid crystal display device having such a conventional nonlinear resistance element has a problem that an afterimage phenomenon occurs when switching the display during driving of the liquid crystal.

This afterimage phenomenon will be described with reference to FIG. Note that this liquid crystal display device has a normally white display.

FIG. 33 shows the change in transmittance when the voltage applied to an arbitrary pixel is changed at 5-minute intervals. That is, first, a display voltage (V1) with a transmittance of 50% is applied for 5 minutes (non-selection period: T1), and then a display voltage (V2) with a transmittance of 10% is applied for 5 minutes (selection period: T2). Then, the same voltage (V3) as the voltage (V1) applied during the first non-selection period of T1 is applied again for 5 minutes (non-selection period: T3).

The afterimage phenomenon is a phenomenon in which a difference (ΔT) occurs in the transmittance even though the voltages applied to the non-selection period T1 and the non-selection period T3 are equal. The transmittance difference ΔT in the above-described liquid crystal display device was 5%.

When such an afterimage phenomenon occurs, display contents different from the image to be displayed originally are displayed.

Therefore, the burning phenomenon, which is an afterimage phenomenon, extremely deteriorates the display quality of the liquid crystal display device.
This is a serious problem in practical use as a liquid crystal display device.

A major cause of the afterimage phenomenon is a DC voltage component applied to the liquid crystal layer during driving. Due to the DC voltage component, a polarization phenomenon of an alignment film used for arranging liquid crystals in a certain direction and an afterimage phenomenon occur due to deterioration of the liquid crystal itself.

FIG. 34 is a graph showing current-voltage characteristics (IV characteristics) of a nonlinear resistance element having a structure of “tantalum film-tantalum oxide film-indium tin oxide film” manufactured by a conventional structure.

As shown in this figure, the current value greatly depends on the polarity of the applied voltage, and the current value is asymmetric with respect to a voltage of zero volt.
3 shows voltage characteristics.

As means for improving this asymmetric current-voltage characteristic,
It is conceivable to replace the indium tin oxide film serving as the upper electrode 105 of the nonlinear resistance element with a metal film such as chromium (Cr) or titanium (Ti).

However, when the upper electrode 105 is converted from an indium tin oxide film to a chromium film or a titanium film, the asymmetry in the current-voltage characteristic as shown in FIG. 34 is slightly relaxed, but the current-voltage characteristic is still completely symmetric. It does not have voltage characteristics.

Further, an offset driving method has been proposed to prevent a DC voltage component from being applied to a liquid crystal layer in a nonlinear resistance element having asymmetric current-voltage characteristics. This offset driving method will be described with reference to FIG.

The offset driving method is, as shown in FIG. 35, changing the voltage applied during the select period (Ts) and the hold period (Th) between a (+) field and a (-) field, respectively. Is a driving method in which a DC voltage component is not applied to the liquid crystal layer by compensating for the asymmetry of the liquid crystal layer with a driving voltage.

The voltages applied during the select period (Ts) are Va1 and Va2, and the voltages applied during the hold period (Th) correspond to Vb1 and Vb2.

By the offset driving method shown in FIG. 35, the DC voltage component between the display electrode 106 and the counter electrode 110 arranged via the liquid crystal layer is reduced.

However, the signal electrodes shown in FIGS. 30 and 31
Asymmetric voltages, for example, Vb2 and Vb1 are applied to 107, but symmetric voltages are applied to the liquid crystal layer. for that reason,
A DC voltage component is generated between the signal electrode 107 and the display electrode 106 on the first substrate 102 forming the MIM element. Further, a DC voltage component is similarly generated between the counter electrode 110 and the signal electrode 107.

Therefore, when the liquid crystal layer has asymmetric current-voltage characteristics, the application of the DC voltage component to the liquid crystal layer cannot be sufficiently reduced, and the afterimage phenomenon cannot be completely eliminated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid crystal display device capable of reducing the application of a DC voltage component to a liquid crystal layer and realizing a good image quality without an afterimage phenomenon in a non-linear resistance element having asymmetric current-voltage characteristics, A method for manufacturing a display device.

DISCLOSURE OF THE INVENTION In order to achieve the above object, the present invention provides the following method for manufacturing a liquid crystal display device and a liquid crystal device.

The method for manufacturing a liquid crystal display device according to the present invention includes the following steps.

A. A metal film is formed on a substrate, and the metal film is patterned by photoetching to form a plurality of anodizing electrodes, a common electrode connecting the anodizing electrodes, and a lower part of the non-linear resistance element portion. B. forming an electrode and a connecting portion connecting the lower electrode and the anodizing electrode; B. using the common electrode as an anode, each anodizing electrode and a connecting portion integrally connected to the common electrode; Forming an insulating film by performing anodizing on the lower electrode and C. forming a transparent conductive film on the insulating film and on the substrate, and patterning the transparent conductive film by photoetching, Forming each display electrode on the substrate so as to provide an overlapping portion covering a part of the connection portion, and forming a signal electrode on each anodizing electrode with a gap between the lower electrode and the signal electrode, Each lower power Forming a first upper electrode connected to the signal electrode and a second upper electrode connected to the display electrode, respectively; D. an area covering the lower electrode and the first and second upper electrodes; E. an insulating film that is an anodic oxide film formed on the metal film by an etching process using the photosensitive resin, the display electrode, and the signal electrode as an etching mask. The connection part of the multi-layer structure consisting of and is completely etched down to the surface of the substrate to have a shape that is self-aligned with the plurality of sides of the display electrode and the signal electrode, and the anodizing electrode under the signal electrode and the display of the connection part The overlapping portion and the lower electrode in the lower layer of the electrode are separated from each other, and the lower electrode is isolated in an island shape,
The lower electrode, the insulating film, and the first and second upper electrodes form first and second nonlinear resistance element portions, and a common electrode connecting the plurality of anodizing electrodes is formed as the signal electrode. A step of electrically removing the anodic oxidation electrodes by etching as an etching mask, and in the step C, the lower electrode and the anodic oxidation electrode of the non-linear resistance element portion of the pixel adjacent to the pixel The display electrode can be formed so as to provide an overlapping portion that covers a part of a connecting portion that connects the display electrodes.

Further, the steps C, D, and E may be replaced with the following steps.

A metal film is formed on the insulating film and the substrate formed in the step B, and the metal film is patterned by a photoetching process to form a signal electrode on the anodizing electrode and on each of the lower electrodes. Forming a first upper electrode connected to the signal electrode and a second upper electrode having a pad portion, respectively; forming a transparent conductive film on the substrate including the insulating film and the pad portion; Patterning a transparent conductive film by a photoetching process to form a display electrode electrically separated from the signal electrode and the lower electrode so as to provide an overlapping portion covering a part of the connection portion and the pad portion; A step of forming a photosensitive resin in a region covering the electrode and the first and second upper electrodes; and a step of forming the photosensitive resin, a display electrode and a signal electrode made of different materials, respectively. By using an etching process using as an etching mask, the connection portion of the multilayer structure including the metal film and the insulating film that is an anodic oxide film formed thereon is completely etched to the surface of the substrate, and the display electrode And a shape that is self-aligned with a plurality of sides of the signal electrode, and an anodizing electrode under the signal electrode and an overlapping portion under the display electrode of the connection portion and a lower electrode are separated from each other to form a lower electrode. The first and second nonlinear resistance element portions are formed by the lower electrode, the insulating film, and the first and second upper electrodes, and are connected to the plurality of anodizing electrodes. Removing the electrodes by etching using the signal electrode as an etching mask to electrically separate the anodizing electrodes; and photosensitive to the area covering the lower electrode and the first and second upper electrodes. The steps after the step of forming the resin can be replaced with the following steps.

Forming a photosensitive resin in a region covering approximately half of each of the first and second upper electrodes on the side facing the lower electrode and a region covering the lower electrode therebetween; Multilayer structure consisting of the above metal film and an insulating film which is an anodic oxide film formed thereon by an etching process using a conductive resin, a display electrode, first and second upper electrodes, and a signal electrode as an etching mask. The connection portion and the lower electrode are completely etched down to the surface of the substrate so that the connection portion is shaped to be self-aligned with a plurality of sides of the display electrode and the signal electrode, and the lower electrode is formed of the first and second upper electrodes. To form a shape that is self-aligned with the outer side of each, and separates the anodizing electrode under the signal electrode and the overlapping portion under the display electrode of the connection portion from the lower electrode, and the lower electrode. A first and a second non-linear resistance element portion are formed by the insulating film and the first and second upper electrodes, and a common electrode connecting the plurality of anodic oxidation electrodes is used as a signal electrode etching mask. As a step of electrically separating each anodizing electrode, in these liquid crystal display device manufacturing methods, a metal film is formed on a substrate, and the metal film is patterned by photoetching, Forming a plurality of anodizing electrodes, a common electrode connecting the anodizing electrodes, a lower electrode of the non-linear resistance element portion, and a connecting portion connecting the lower electrode and the anodizing electrode; Then, the connection portion is formed integrally with an anodizing electrode formed under a signal electrode in a row or a column different from the signal electrode to which the nonlinear resistance element portion of the pixel is connected, and the display electrode is formed. In the forming step, the display electrode can be formed so as to provide an overlapping portion that covers a part of a connection portion connected to a lower electrode of a nonlinear resistance element portion of a pixel adjacent to the pixel.

The steps D and E in the method of manufacturing a liquid crystal display device having the steps A to E described first may be replaced with the following steps.

After each of the steps A to C, a protective insulating film is formed on the entire surface including the electrodes and the connection portions on the substrate, and photo-etching is performed. Forming an opening in a region including an overlapping portion and a portion exposed from the display electrode, and an etching process using the protective insulating film and the display electrode and the signal electrode in each opening as an etching mask. This completely etches the connection portion of the multilayer structure composed of the metal film and the insulating film which is an anodic oxide film formed thereon to the surface of the substrate, and self-aligns with the plurality of sides of the display electrode and the signal electrode. In this case, the anodizing electrode in the lower layer of the signal electrode and the overlapping portion and the lower electrode in the lower layer of the display electrode of the connection part are separated from each other, and the lower electrode is isolated in an island shape. Forming a first and a second non-linear resistance element portion by the lower electrode, the insulating film, and the first and second upper electrodes; by these manufacturing methods, a pair of non-linear resistance elements having good symmetry for each pixel; And a liquid crystal display device having good image quality with no afterimage phenomenon can be efficiently manufactured.

Further, the present invention also provides the following liquid crystal display device.

Having display electrodes arranged in a matrix on the substrate,
In a liquid crystal display device in which the display electrode is a pixel portion, the configuration is as follows.

An anodizing electrode and an island-like lower electrode, both of which are made of a metal film, an insulating film provided on the surface of the metal film, and a transparent conductive film provided on the lower electrode with an insulating film interposed therebetween, on the substrate. , Two upper electrodes, a display electrode made of a transparent conductive film, and a signal electrode made of a metal film or a metal film and a transparent conductive film.

The two upper electrodes cross the lower electrode,
Two non-linear resistance element portions are constituted by one upper electrode, an insulating film, and a lower electrode. One of two upper electrodes constituting the nonlinear resistance element portion is connected to a signal electrode, and the other is connected to the display electrode.

The display electrode constituting the pixel portion has a display electrode having an overlap portion under which a two-layer film of the same metal film and insulating film as the lower electrode remains, and does not have the overlap portion under the display electrode. It consists of two types of display electrodes, a display electrode.

In the case of a liquid crystal display device in which one pixel is constituted by a plurality of display electrodes, the display electrode which constitutes one pixel portion includes:
A display electrode having an overlapping portion below which a two-layer film of the same metal film as the lower electrode and the insulating film remains, and a display electrode having no overlapping portion below the display electrode. Become.

Alternatively, a display electrode forming one pixel portion has an overlap portion under which a two-layer film of the same metal film and the insulating film as the lower electrode remains, and does not have the overlap portion thereunder. It is preferable that two types of display electrodes, ie, a display electrode, and the non-linear resistance element portions of a plurality of display electrodes constituting one pixel portion be concentrated.

Further, on the substrate, an anodic oxidation electrode and a lower electrode, both made of a metal film, an insulating film provided on the surface of the metal film, an upper electrode provided on the lower electrode via an insulating film, A display electrode connected to the upper electrode; and a signal electrode including the lower electrode or the lower electrode and an insulating film.

The upper electrode intersects the lower electrode, and the upper electrode, the insulating film, and the lower electrode constitute a nonlinear resistance element. The anodizing electrode or a part of the anodizing electrode and the insulating film is formed. In addition, the present invention also provides an electrode having an overlapping portion that remains under the display electrode.

It is preferable that one of the two upper electrodes constituting the non-linear resistance element is connected to a signal electrode and the other is connected to a display electrode.

In a liquid crystal display device, it is important to reduce the ratio of a display electrode and a portion that cannot be used for display in a peripheral portion in order to improve display quality. In the case of a high-density liquid crystal display device, it is important to reduce the area of the peripheral portion.

Therefore, the area occupied by the connection portion is reduced by providing the display electrode in which the non-linear resistance element is concentrated and the display electrode in which the two-layer film of the metal film and the insulating film exists and the display electrode which does not exist are provided below the display electrode. Since the area of the light shielding portion is small, bright display can be performed.

Further, in the case of a liquid crystal display device in which one pixel portion is composed of a plurality of display electrodes, the nonlinear resistance element portion is concentrated and
By reducing the number of display electrodes in which the two-layer film is present below the display electrodes as compared with the number of display electrodes not present, the area of the connection portion for shielding light is reduced, so that the display electrodes are effectively used. be able to.

In the case of a high-density liquid crystal display device or a large-area liquid crystal display device in which the pitch of the pixel portion is small, the width of the anodizing electrode is limited. Therefore, before the anodizing is completed, the width of the anodizing electrode is used in a large state, and after forming the display electrode, a part of the anodizing electrode is processed and removed. As a result, the width of the anodizing electrode can be increased, so that the insulating film can be uniformly formed in a short time even in the case of a high-density liquid crystal display device or a large-area liquid crystal display device.

Furthermore, when separating the connecting portion between the anodizing electrode and the island-shaped lower electrode, a part of the anodizing electrode is processed using the display electrode as a mask, so that a short time and uniform insulation can be achieved without increasing the number of manufacturing steps. A film can be formed.

Further, the overlapping portion of the anodic oxidation electrode remaining under the display electrode can be used as a part of the black matrix, and the positional accuracy between the black matrix and the display electrode can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a portion constituting a non-linear resistance element of a liquid crystal display device according to a first embodiment of the present invention, and FIG. 2 is an enlarged sectional view taken along line II-II in FIG. FIG. 3 is a diagram showing current-voltage characteristics of the nonlinear resistance element, FIG. 4 is a diagram showing an afterimage phenomenon in the liquid crystal display device, and FIG.
The figure is a timing chart showing the driving waveform applied to the scanning electrodes of the liquid crystal display device.

FIG. 6 is a plan view of an initial step for explaining a method of manufacturing the liquid crystal display device according to the first embodiment of the present invention, and FIG.
FIG. 8 and FIG. 8 are plan views of the intermediate step, and FIG. 9 is a plan view of the completed state.

FIG. 10 is a plan view of an initial step for describing a second embodiment of the liquid crystal display device according to the present invention and a method of manufacturing the same,
11 to 14 are plan views of the intermediate and final steps, and FIG. 15 is an enlarged sectional view taken along line XV-XV in FIG.

16 and 17 are plan views of an intermediate step and a final step for explaining a liquid crystal display device according to a third embodiment of the present invention and a method of manufacturing the same.

18 and 19 are plan views of an intermediate step and a final step for explaining a fourth embodiment of the liquid crystal display device according to the present invention and a method of manufacturing the same, and FIG.
It is an expanded sectional view which follows an XX line.

FIG. 21 and FIG. 22 are plan views of portions constituting a nonlinear resistance element of another different embodiment of the liquid crystal display device according to the present invention.

FIG. 23 is a plan view of a portion forming a nonlinear resistance element of a liquid crystal display device according to a fifth embodiment of the present invention, and FIG. 24 is a cross-sectional view taken along the line XXIX-XXIX in FIG.

FIG. 25 is a plan view of a portion forming a nonlinear resistance element of a sixth embodiment of the liquid crystal display device according to the present invention, and FIG. 26 is a cross-sectional view taken along the line XXVI-XXVI in FIG.

FIG. 27 is a plan view of a portion forming a nonlinear resistance element of a liquid crystal display device according to a seventh embodiment of the present invention, and FIG. 28 is a sectional view taken along line XXVIII-XXVIII in FIG.

FIG. 29 is a plan view showing a conventional liquid crystal display of this type,
30 is an enlarged plan view showing a region surrounded by a two-dot chain line circle A in FIG. 29, FIG. 31 is a plan view showing a nonlinear resistance element portion, and FIG. 32 is a plan view of FIG. It is sectional drawing which follows -B.

FIG. 33 is a diagram showing the afterimage phenomenon in the conventional liquid crystal display device, FIG. 34 is a diagram showing the current-voltage characteristic of the nonlinear resistance element, and FIG. 35 is a drive voltage waveform similarly applied to the signal electrode. It is a timing chart figure which shows.

BEST MODE FOR CARRYING OUT THE INVENTION In order to explain the contents of the present invention in more detail, embodiments of the present invention will be described with reference to the accompanying drawings.

First Embodiment FIG. 1 is a plan view showing a partial region of a first substrate on which a non-linear resistance element (MIM element) is formed in a first embodiment of a liquid crystal display device according to the present invention. . Figure 2 shows
It is an expanded sectional view which follows an II-II line. First, the configuration of the liquid crystal display device according to the first embodiment will be described with reference to these drawings.

An anodizing electrode 3 made of a tantalum (Ta) film, which is a metal film, and a lower electrode 2 are formed on a transparent first substrate 1 which is an active substrate for forming a non-linear resistance element portion.
And a connection part 4 for connecting the anodizing electrode 3 and the lower electrode 2.

The anodizing electrode 3 has one end connected to the common electrode 6 and the other end connected to an input unit 7 for applying a signal from an external circuit to the nonlinear resistance element unit. This common electrode 6
Is used as an electrode when the insulating film 8 is formed on the surface of the lower electrode 2 by anodic oxidation.

Connection 4 between signal electrode 9 and display electrode 12 in FIG.
And the region indicated by the two-dot chain line 5 such as the connection portion 4 between the common electrode 6 and the display electrode 12 in the right region of the first upper electrode 10 is used in a processing step in a manufacturing method described later. Will be removed.

That is, FIG. 1 shows the middle of the manufacturing process so that the description can be easily understood.

Further, an insulating film 8 made of a tantalum oxide (Ta ₂ O ₅ ) film formed by anodizing the lower electrode 2 is provided on the surface of the lower electrode 2.

Further, a transparent conductive film is provided on the anodizing electrode 3 to form a signal electrode 9. Then, a first upper electrode 10 connected to the signal electrode 9 is provided on the lower electrode 2, and a second upper electrode 11 connected to the display electrode 12 is provided on the lower electrode 2.

The first upper electrode 10 and the second upper electrode 11 are provided on the island-shaped lower electrode 2 via an insulating film 8.

Then, a first non-linear resistance element portion 13 is constituted by the lower electrode 2, the insulating film 8 and the first upper electrode 10, and a second non-linear resistance element portion 13 is constituted by the lower electrode 2, the insulating film 8 and the second upper electrode 11. The nonlinear resistance element section 14 is configured.

Here, the signal electrode 9, the first upper electrode 10, the second upper electrode 11, and the display electrode 12 are all formed of a transparent conductive film, for example, an indium tin oxide (ITO) film.

The signal electrode 9 for connecting to an external circuit is further connected to the input unit 7.

A partial region of the display electrode 12 has an overlapping portion 15 which is a region overlapping with a partial region of the connecting portion 4 connecting the anodizing electrode 3 and the lower electrode 2.

The display electrode 12 and the signal electrode 9 in a part of the connection portion 4 are separated from each other to form an island-like lower electrode 2.

Here, the first non-linear resistance element portion 13 and the second non-linear resistance element portion 14 provided in the region between the signal electrode 9 and the display electrode 12 are composed of "indium tin oxide film-tantalum oxide film-tantalum film". It comprises a first non-linear resistance element section 13 and a second non-linear resistance element section 14 composed of "tantalum film-tantalum oxide film-indium tin oxide film".

That is, looking at the current path from the signal electrode 9 to the display electrode 12, the “indium tin oxide film-tantalum oxide film-tantalum film” of the first non-linear resistance element portion 13 changes to the second non-linear resistance element portion 14. It flows to “a tantalum film—a tantalum oxide film—an indium tin oxide film”.

Therefore, the connection of the nonlinear resistance element from the signal electrode 9 to the display electrode 12 and the connection of the nonlinear resistance element from the display electrode 12 to the signal electrode 9 have a symmetric structure.

The current-voltage (IV) characteristics of the nonlinear resistance element according to the first embodiment will be described with reference to FIG.

Since the non-linear resistance element has a symmetric structure between the display electrode and the signal electrode, as shown in FIG. 3, the non-linear resistance element has a characteristic that the current (I) is symmetric on the positive side and the negative side of the applied voltage (V).

The afterimage phenomenon in this case will be described with reference to FIG.

FIG. 4 shows the transmittance of the pixel of the liquid crystal display device having the nonlinear resistance element according to the present invention as described above with reference to FIG. Shows the change. This liquid crystal display device is a normally white display.

First, a display voltage (V1) with a transmittance of 50% is applied for 5 minutes (non-selection period: T1), and then a display voltage (V1) with a transmittance of 10% is applied.
2) is applied for 5 minutes (selection period: T2), and the first
The same voltage (V1) as the voltage (V1) applied during the non-selection period of T1
3) is applied for 5 minutes (non-selection period: T3).

As described above, the afterimage phenomenon is a phenomenon in which a difference (ΔT) occurs in the transmittance even though the voltages applied to the non-selection period T1 and the non-selection period T3 are equal.

By using the nonlinear resistance element according to the first embodiment of the present invention, the difference in transmittance (ΔT) is reduced to 1% or less as shown in FIG. Further, the difference ΔT in transmittance decreases rapidly with time.

Next, an example of a voltage waveform applied to the signal electrode 9 in this liquid crystal display device will be described with reference to FIG.

The voltage applied during the select period Ts and the hold period Th is
Vs1 and Vh1 in the (+) field respectively,
Vs2 and Vh2 in the (-) field. Since the current-voltage characteristics of the nonlinear resistance element are symmetric, the absolute values of the voltages Vs1 and Vs2 and the absolute values of the voltages Vh1 and Vh2 can be made equal.

As is clear from the above description, according to the configuration of this embodiment, the nonlinear resistance element of the liquid crystal display device has a symmetric current-voltage characteristic.

Therefore, the application of the DC voltage component to the liquid crystal layer during driving is almost eliminated, and the voltage waveform applied to the signal electrode can be made symmetrical.

As a result, the application of the DC voltage component between the signal electrode and the display electrode and between the signal electrode and the counter electrode is eliminated, and it is possible to prevent the occurrence of an afterimage phenomenon which is a problem in display.
Therefore, a liquid crystal display device having good display quality can be obtained.

Next, a method of manufacturing the active substrate of the liquid crystal display device shown in FIGS. 1 and 2 will be described with reference to FIGS. 6 to 9 are plan views showing a method of manufacturing the active substrate of the liquid crystal display device according to the first embodiment of the present invention in the order of steps.

First, as shown in FIG. 6, a tantalum (Ta) film having a thickness of 250 nm is formed as a metal film on the entire surface of the first substrate 1, which is an active substrate made of glass, by a sputtering method.

Thereafter, a photosensitive resin (not shown) is applied and formed on the entire surface of the tantalum film by a spin coating method, exposed and developed using a predetermined photomask, and a pattern of the photosensitive resin is formed. The lower electrode 2, the anodic oxidation electrode 3 connected to the lower electrode 2 via the connection portion 4, and the anodic oxidation electrode 3 are formed by photoetching processing of etching the tantalum film using a photosensitive resin as an etching mask. And a common electrode 6 to be connected thereto are patterned.

Here, the etching of the tantalum film is performed using a reactive ion etching (hereinafter referred to as RIE) apparatus.

As for the etching conditions, a mixed gas of sulfur hexafluoride (SF ₆ ) and oxygen (O ₂ ) is used as an etching gas.
And sulfur hexafluoride flow rate is 100 _~ 200 _sccm , oxygen flow rate is
The operation is performed at 10 to 40 _sccm , at a pressure of 4 to 12 × 10 ^-2 _torr, and at a power consumption of 0.2 to 0.5 kW / cm ² .

Thereafter, the common electrode 6 is used as an anode, and as an anodic oxidizing solution,
Anodizing of the tantalum film is performed by applying a voltage of 10 to 20 V using an aqueous solution of citric acid or an aqueous solution of ammonium borate of 0.01 to 1.0 wt%.

As a result, the lower electrode 2, the anodic oxidation electrode 3 and the connection portion 4
An insulating film made of a tantalum oxide film (Ta ₂ O ₅ ) having a thickness of 35 nm is formed on the side wall and the upper surface of the substrate.

Next, as shown in FIG. 7, an indium tin oxide (ITO) film having a thickness of 100 nm is formed as a transparent conductive film over the entire surface by using a sputtering method. After that, a photosensitive resin is formed on the indium tin oxide film.

Then, the indium tin oxide film is subjected to an etching treatment, and the display electrode 12, the second upper electrode 11 connected to the display electrode 12, the signal electrode 9, and the first upper electrode 10 connected to the signal electrode 9 are formed. And the input section 7 connected to the signal electrode 9 are simultaneously patterned.

At this time, the input portion 7 is entirely covered with indium tin oxide, and is patterned so as to extend to the left in FIG. 7, and the common electrode 6 is patterned with indium tin oxide so that the tantalum film is exposed.

The etching of the indium tin oxide is performed by wet etching using an aqueous solution etchant of ferric oxide and hydrochloric acid. The etchant temperature at this time was 30
Set to -40 ° C.

As shown in the plan view of FIG. 7, a partial area of the display electrode 12 covers a partial area of the connection portion 4. This display electrode 12
An area where the connection part 4 overlaps with the connection part 4 is referred to as an overlapping part 15.

Next, as shown in FIG. 8, a photosensitive resin is formed on the entire surface, and the first upper electrode 10 is formed by a photolithography process of performing an exposure process and a development process using a predetermined photomask.
A photosensitive resin 21 is formed so as to cover and the second upper electrode 11.

The connection portion 4 connecting the anodizing electrode 3 and the common electrode 6 and the region exposed from the display electrode 12 of the connection portion 4 between the lower electrode 2 and the display electrode 12 are connected to the display electrode 12. 12
Using RIE and photosensitive resin 21 as an etching mask
Etching is performed using an apparatus.

This etching condition uses a mixed gas of sulfur hexafluoride (SF ₆ ) and oxygen (O ₂ ) as an etching gas.
And sulfur hexafluoride flow rate is 100 _~ 200 _sccm , oxygen flow rate is
The operation is performed at 10 to 40 _sccm , at a pressure of 4 to 12 × 10 ^-2 _torr, and at a power consumption of 0.2 to 0.5 kW / cm ² .

Under the above etching conditions, only the tantalum film of the connection portion 4 and the tantalum oxide film of the insulating film 8 can be etched without substantially etching indium tin oxide.

By this etching process, as shown in FIG. 9, the connection portion 4 between the anodizing electrode 3 and the display electrode 12 is cut and separated, the common electrode 6 is removed, and the gap between the display electrode 12 and the lower electrode 2 is removed. And disconnection of the connecting portion 4 can be performed.

By the above steps, as shown in FIGS. 9 and 2, the island-shaped lower electrode 2 separated from the anodizing electrode 3, the insulating film 8 formed on the lower electrode 2, and the signal electrode 9 are formed. A first non-linear resistance element portion comprising a first upper electrode 10 to be connected
13 can be formed.

Further, a second non-linear resistance element portion 14 comprising the island-shaped lower electrode 2, the insulating film 8 formed on the lower electrode 2, and the second upper electrode 11 connected to the display electrode 12 is formed. Can be.

Then, a configuration in which one end of the signal electrode 9 is connected to the input unit 7 can be formed.

The drive signal applied from the outside is applied to the display electrode 12 via “input unit 7-signal electrode 9-first nonlinear resistance element unit 13-second nonlinear resistance element unit 14”.

A partial region of the display electrode 12 includes an overlap portion 15 made of a tantalum film and overlapping the substantially L-shaped connection portion 4.

In this manufacturing method, the photosensitive resin 21 and the display electrode 12 are used as an etching mask when the connecting portion 4 is processed by etching. Therefore, the connection portion 4 can be formed in a shape that matches the lower surface region of the display electrode 12.

Then, since the etching process is performed using the photosensitive resin 21 formed so as to cover the first upper electrode 10 and the second upper electrode 11 as an etching mask, the island-shaped lower electrode 2 can be formed. .

Here, the non-linear resistance element portion formed between the signal electrode 9 and the display electrode 12 is a first non-linear resistance element portion 13 having a “indium tin oxide-tantalum oxide-tantalum” structure.
And a second non-linear resistance element portion 14 having a “tantalum-tantalum oxide-indium tin oxide” structure.

That is, looking at the current path from the signal electrode 9 to the display electrode 12, the indium tin oxide-tantalum oxide-tantalum of the first non-linear resistance element portion 13 changes from the tantalum-tantalum oxide-tantalum oxide of the second non-linear resistance element portion 14. It will flow to indium tin oxide.

Therefore, the connection of the nonlinear resistance element from the signal electrode 9 to the display electrode 12 and the connection of the nonlinear resistance element from the display electrode 12 to the signal electrode 9 have a symmetric structure.

By using the method of manufacturing an active substrate described as the first embodiment, it is possible to manufacture a non-linear resistance element having good symmetry.

Therefore, the application of the DC component to the liquid crystal layer is eliminated, and the occurrence of an afterimage phenomenon which is a problem in display can be prevented, and the display electrode can be used as an etching mask.

Therefore, in the step of separating the anodizing electrode 3 and the lower electrode 2, the photosensitive resin 21 only needs to be formed on the upper surfaces of the first nonlinear resistance element portion 13 and the second nonlinear resistance element portion 14. .

For this reason, the positional accuracy of the region where the photosensitive resin 21 is formed can be reduced as compared with the related art. In addition, it is possible to reliably separate the connection portion 4 from the lower electrode 2 and the connection portion 4 from the anodizing electrode 3. Therefore, a liquid crystal display device having good display quality can be obtained.

Second Embodiment Next, the structure of a first substrate forming a nonlinear resistance element of a liquid crystal display device according to a second embodiment of the present invention and a method of manufacturing the same will be described with reference to FIGS. explain.

10 to 14 are plan views showing the steps of manufacturing the liquid crystal display device according to the second embodiment of the present invention, and FIG. 15 is an enlarged sectional view taken along line XV-XV in FIG.

First, the configuration of the liquid crystal display device according to the second embodiment will be described.
This will be described with reference to FIG. 14 and FIG.

The non-linear resistance element portion provided between the signal electrode 35 and the display electrode 51 includes a first upper electrode 36 made of a chromium film, an insulating film 60 made of a tantalum oxide film, and a lower electrode 32 made of a tantalum film. A first non-linear resistance element section 62.

Further, a second non-linear resistance element portion 63 including a lower electrode 32 made of a tantalum film, an insulating film 60 made of a tantalum oxide film, and a second upper electrode 38 made of a chromium film is provided.

One end of the anodizing electrodes 29 and 30 is connected to the common electrode, and the other end is connected to the input unit 40.

On the surface of the lower electrode 32, an insulating film 60 made of a tantalum oxide film formed by anodizing the lower electrode 32 is provided.

Further, a chromium film is provided as a metal film on the upper surfaces of the anodizing electrodes 29 and 30, and a signal electrode 35 composed of a tantalum film, a chromium film and a two-layer film is formed.

This signal electrode 35 intersects with the lower electrode 32 and
An extension is provided so as to be the first upper electrode 36 provided thereon.

The second upper electrode 38 which crosses the lower electrode 32 and is provided on the lower electrode 32 is connected to the display electrode 51 via the pad portion 37.
The second upper electrode 38 is also made of a chromium film. The display electrode 51 is made of a transparent conductive film such as indium tin oxide.

As shown in FIGS. 12 and 13, the connection portion 31 connecting the lower electrode 32 and the anodizing electrode 29 has an overlap portion 53 overlapping the display electrode 51. Note that an insulating film 60 is interposed between the display electrode 51 and the connection portion 31.

The overlapping portion 53 has a size approximately half the width of the connecting portion 31, and the connecting portion 31 exposed from the display electrode 51 is an exposed region 57.

By removing the exposed region 57 after the formation of the display electrode 51, it is separated into the island-like lower electrode 32 and the anodizing electrode 29 as shown in FIG.

Further, the input section 40 has an input electrode section 39 made of a chromium film.
And a connection input electrode portion 54 made of a transparent conductive film.

As a result, the first non-linear resistance element portion 62 provided between the signal electrode 35 and the display electrode 51 has a “chromium film-tantalum oxide-
The second non-linear resistance element section 63 has a "tantalum-tantalum oxide-chromium film" structure.

Therefore, the connection of the non-linear resistance element from the signal electrode 35 to the display electrode 51 and the connection of the non-linear resistance element from the display electrode 51 to the signal electrode 35 have a symmetric structure.

Therefore, a non-linear resistance element having good symmetry can be obtained,
This eliminates the application of a DC component to the liquid crystal layer, and can prevent the occurrence of an afterimage phenomenon that is a display problem.

Next, a method of manufacturing the liquid crystal display device according to the second embodiment shown in FIGS. 14 and 15 will be described.

First, as shown in FIG. 10, a 100 nm thick tantalum (Ta) film is formed as a metal film on a first substrate 1 made of glass by a sputtering method. Thereafter, a photosensitive resin (not shown) is formed on the tantalum film.

Thereafter, by performing an etching process using the photosensitive resin as an etching mask, the lower electrode 32, which is made of a tantalum film, and the lower electrode 32 and the connecting portion 31
Anodizing electrode 29 connected via a common electrode 34 connected to the anodizing electrode 29 and the anodizing electrode 30,
An input section 40 for inputting a scanning signal of an external circuit is patterned. The etching of the tantalum film is performed using an RIE apparatus under the above-described etching conditions.

FIG. 10 shows an anodizing electrode 30 corresponding to the n-th scanning electrode and an anodizing electrode 29 corresponding to the (n + 1) -th scanning electrode.

In the second embodiment, the lower electrode 32 forming the n-th non-linear resistance element portion is connected to the (n + 1) -th anodizing electrode 29 via the connection portion 31.

After that, the common electrode 34 was used as an anode, and the anode was used as an anodizing solution.
Anodizing of the tantalum film is performed by applying a voltage of 10 to 20 V using an aqueous solution of citric acid or an aqueous solution of ammonium borate of 01 to 1.0 wt%.

As a result, the tantalum oxide film (Ta) is formed on the side walls and the upper surface of the lower electrode 32, the anodic oxidation electrodes 29, 30 and the connection portion 31.
_An insulating film made of ₂ O ₅ ) can be formed with a thickness of 35 nm.

Next, as shown in FIG. 11, a chromium (Cr) film having a thickness of 50 nm is formed on the upper surfaces of the first substrate 1 and the insulating film 60 by a sputtering method. Thereafter, a photosensitive resin is formed on the chromium film.

After that, the signal electrode 35 formed of a chromium film is formed on the anodic oxidation electrodes 29 and 30 by etching using a photosensitive resin as an etching mask. Upper electrode 36 and display electrode
A second upper electrode 38 having a pad portion 37 connected to 51 is patterned.

Here, the signal electrode 35 is connected to the input
Connected to 39. Further, the chromium film is not formed on the common electrode 34.

The chromium film is etched by wet etching using an aqueous solution etchant of perchloric acid and cerium ammonium nitrate. The liquid temperature of the etchant is set at 20 ° C to 30 ° C.

Next, as shown in FIG. 12, an indium tin oxide (ITO) film having a thickness of 100 nm is formed as a transparent conductive film by a sputtering method. After that, a photosensitive resin is formed on the indium tin oxide film.

Then, an etching process is performed using the photosensitive resin as an etching mask to form an n-th display electrode 51 connected to the n-th signal electrode 35 made of an indium tin oxide film via a non-linear resistance element portion. .

The display electrode 51 overlaps with a portion of the connecting portion 31 connecting the lower electrode 32 and the anodizing electrode 29 with an overlapping portion 53 and a pad portion 37 extending with the second upper electrode 38. The pattern is formed so as to form the overlapping portion 52.

Further, as shown in FIG. 12, a connection input electrode portion 54 formed so as to cover the anodic oxidation electrode 30 at the input portion 40 is patterned at the same time as the display electrode 51 is formed.

Then, as shown in FIG. 13, the first upper electrode 36 and the second
A photosensitive resin 55 is formed by photolithography so as to cover the upper electrode 38 and the lower electrode 32.

Thereafter, as shown in FIG. 14, the common electrode 34 and n + 1
Among the connecting portions 31 connecting the second anodizing electrode 29 and the lower electrode 32, an exposed region (indicated by a phantom line in FIG. 14) in which the connecting portion 31 that is not the overlapping portion 53 is exposed is exposed. Then, the display electrode 51 and the photosensitive resin 55 are removed by performing an etching process using the photosensitive resin 55 as an etching mask.

As a result, the connection portion 31 and the anodizing electrode 29 and the connection portion 31 and the lower electrode 32 are separated by etching to form an island-shaped lower electrode 32.

Furthermore, at the same time as this etching process, the photosensitive resin 55
The exposed region 32a (shown by a phantom line) of the lower electrode 32 on the opposite side of the connection portion 31 which is not covered with the metal is also etched away. Note that the photosensitive resin 55
Can be patterned.

In this way, the first upper electrode 36 composed of the island-like lower electrode 32 separated from the (n + 1) -th anodizing electrode 29, the insulating film 60, and the first upper electrode 36 connected to the n-th signal electrode 35 is formed. The non-linear resistance element section 62 is formed.

Further, a second non-linear resistance element portion 63 including an island-shaped lower electrode 32, an insulating film 60, and a second upper electrode 38 connected to the n-th display electrode 51 via a pad portion 37 is formed. .

One of the signal electrodes 35 is connected to the input unit 40. The input section 40 is a connection electrode composed of an input electrode section 39 made of a chromium film formed on the upper surfaces of the anodizing electrodes 29 and 30 and a transparent conductive film formed on the upper surface of the input electrode section 39. The input electrode unit 54 can be formed.

Then, an external signal is input to the input section 40-the signal electrode 35-the first
Is applied to the display electrode 51 via the non-linear resistance element section 62 -the second non-linear resistance element section 63.

As shown in FIGS. 14 and 15, the display front electrode 51 includes a connection portion 31 for connecting the anodizing electrodes 29 and 30 and the lower electrode 32.
And an overlapping portion 53 that overlaps.

When the connection portion 31 is removed by the etching method, the display electrode 51 is used as an etching mask. Therefore, the lower electrode is separated from the display electrode 51 of the connection portion 31 by an exposed region (indicated by a virtual line in FIG. 14) which does not overlap with the display electrode 51.
32 can be formed.

Thus, by using the method for manufacturing an active substrate according to the second embodiment of the present invention, it is possible to manufacture a non-linear resistance element having good symmetry.

As a result, the application of the DC component to the liquid crystal layer is eliminated, the occurrence of an afterimage phenomenon which is a problem in display can be prevented, and the display electrode 51 can be used as a mask for etching.

Therefore, when separating the anodizing electrode 29 and the lower electrode 32, the photosensitive resin 55 is formed in the upper surface area of the two upper electrodes 36, 38 and the lower electrode 32 as shown in FIG. Just do it. For this reason, the positional accuracy of the region where the photosensitive resin 55 is formed can be lessened than before.

Furthermore, since the connection part 31 remaining in the lower layer of the display electrode 51 is made of a metal film, light can be shielded.

Therefore, when used as a transmissive liquid crystal display device, the remaining connection portion 31 can be used as a light shielding film. Accordingly, light can be partially shielded on the first substrate on which the non-linear resistance element portion is formed.

Third Embodiment Next, a structure of a liquid crystal display device according to a third embodiment of the present invention and a method for manufacturing the same will be described with reference to FIGS.

FIGS. 16 and 17 are plan views showing a partial area of the liquid crystal display device for describing the structure and the manufacturing method of the liquid crystal display device according to the third embodiment of the present invention. FIG. 15 is a diagram corresponding to FIGS. 13 and 14 used for describing the second embodiment.

First, the configuration of the liquid crystal display device according to the third embodiment of the present invention will be described with reference to FIG.

The non-linear resistance element portion provided between the signal electrode 35 and the display electrode 51 includes a first upper electrode 36 made of a chromium film, an insulating film made of a tantalum oxide film, and a lower electrode 32 made of a tantalum film. A first non-linear resistance element section 62.

Further, a second non-linear resistance element portion 63 composed of a lower electrode 32 made of a tantalum film, an insulating film 60 made of a tantalum oxide, and a second upper electrode 38 made of a chromium film is provided.

Then, as shown in FIG. 16, the lower electrode 32 is
The lower electrode 32 is connected to the first upper electrode 36 and the second upper electrode 38 through the first upper electrode 36 and the second upper electrode 36. It is removed to match the electrode 38.

Note that the lower electrode 32 between the first upper electrode 36 and the second upper electrode 38 is left.

One ends of the anodizing electrodes 29 and 30 are connected to the common electrode 34, and the other ends are connected to the input unit 40.

On the surface of the lower electrode 32, an insulating film made of a tantalum oxide film formed by anodizing the lower electrode 32 is provided.

Further, a chromium film is provided on the upper surfaces of the anodizing electrodes 29 and 30, and the signal electrode 35 is formed of a two-layer film of a tantalum film and a chromium film.

Further, one signal electrode 35 is provided with an extended portion that intersects with the lower electrode 32 and becomes a first upper electrode 36 provided on the lower electrode 32.

A second electrode that crosses the lower electrode 32 and is provided on the lower electrode 32;
The upper electrode 38 is connected to the display electrode 51 via the pad portion 37. The second upper electrode 38 is also made of a chromium film. The display electrode 51 is made of a transparent conductive film such as indium tin oxide.

Connection section 31 for connecting lower electrode 32 and anodizing electrode 29
Has an overlapping portion 53 that overlaps the display electrode 51. Note that an insulating film is interposed between the display electrode 51 and the connection portion 31.

The overlapping portion 53 has a dimension approximately half the width of the connecting portion 31, and the connecting portion 53 exposed from the display electrode 51 is an exposed region 57 as shown in FIG.

Then, by removing the exposed region 57 after the formation of the display electrode 51, it is separated into the island-like lower electrode 32 and the anodizing electrode 29 as shown in FIG.

Further, the input section 40 has an input electrode section 39 made of a chromium film.
And a connection input electrode portion 54 made of a transparent conductive film.

As a result, the first non-linear resistance element portion 62 provided between the signal electrode 35 and the display electrode 51 has a chromium film-tantalum oxide-
It has a tantalum film structure, and the second nonlinear resistance element portion 63
It has a tantalum film-tantalum oxide-chromium film structure.

Therefore, the connection of the nonlinear resistance element from the signal electrode 35 to the display electrode 51 and the connection of the nonlinear resistance element from the display electrode 51 to the signal electrode 35 have a symmetric structure.

Therefore, a non-linear resistance element having good symmetry can be obtained,
This eliminates the application of a DC component to the liquid crystal layer, and can prevent the occurrence of an afterimage phenomenon that is a display problem.

Here, a method of manufacturing the liquid crystal display device according to the third embodiment of the present invention shown in FIGS. 16 and 17 will be described.

First, a tantalum (Ta) film having a thickness of 100 nm is formed on the entire surface of the insulating first substrate 1 by a sputtering method. After that, a photosensitive resin is formed on the tantalum film.

Then, the tantalum film is etched to form a lower electrode 32, an anodizing electrode 29 connected to the lower electrode 32 via a connection portion 31, and another anodizing electrode 30,
Common electrode 34 connected to these anodizing electrodes 29, 30
And an input section 40 for inputting a scanning signal of an external circuit are patterned. This tantalum film is etched using an RIE device.

FIG. 16 shows an anodizing electrode 30 corresponding to the n-th scanning electrode and an anodizing electrode 29 corresponding to the (n + 1) -th scanning electrode. In this embodiment, the lower part of the n-th non-linear resistance element is shown. Electrode 32 is the (n + 1) th anodizing electrode 29
Are connected to each other via a connection unit 31.

Thereafter, anodizing of the tantalum film is performed using the common electrode 34 as an anode and an aqueous citric acid solution or an aqueous ammonium borate solution as an anodizing solution.

As a result, a tantalum oxide film (Ta ₂ O) is formed on the surface of the side wall and upper surface of the lower electrode 32, the anodic oxidation electrodes 29 and 30, and the connection portion 31.
₅ ) An insulating film consisting of 35) can be formed with a thickness of 35 nm.

Next, a chromium (Cr) film having a thickness of 50 nm is formed on the upper surfaces of the first substrate 1 and the insulating film by a sputtering method. Thereafter, a photosensitive resin is formed on the chromium film.

Thereafter, the chromium film is etched to form a signal electrode 35, a first upper electrode 36 connected to the signal electrode 35, and a pad portion connected to the display electrode 51 on the anodizing electrodes 29 and 30.
A second upper electrode 38 having 37 is patterned.

Further, in the input section 40, the input electrode section 39 is simultaneously formed of a chromium film so as to be connected to the input electrode section 39 in the input section 40. Here, the chromium film is not formed on the common electrode.

Next, an indium tin oxide (ITO) film having a thickness of 100 nm is formed as a transparent conductive film over the entire surface by a sputtering method. Thereafter, a photosensitive resin is formed on the indium tin oxide film.

Then, using the photosensitive resin as an etching mask, the indium tin oxide film is etched using an RIE apparatus, and the n-th display electrode 51 connected to the n-th signal electrode 35 via a non-linear resistance element. Is patterned.

Further, the display electrode 51 is composed of the lower electrode 32 and the anodizing electrode.
An overlapping portion 53 overlapping a partial region of the connecting portion 31 connecting the second upper electrode 38 and a pad portion of a partial region of the second upper electrode 38;
So as to form an overlapping portion 52 overlapping 37.
A pattern is formed by photoetching.

At this time, the overlap width between the connection part 31 and the display electrode 51 is set to approximately half the width of the connection part 31 and the display electrode 51 is overlapped.
The connecting portion 31 not covered with is defined as an exposed region 57.

Furthermore, in the input section 40, the anodizing electrodes 29, 3
The connection input electrode portion 54 covering 0 is simultaneously patterned with a transparent conductive film.

Thereafter, an area approximately half of the first upper electrode 36 on the lower electrode 32, an approximately half area of the second upper electrode 38,
Lower electrode between first upper electrode 36 and second upper electrode 38
The photosensitive resin 71 is patterned by a photolithography process so as to cover the substrate 32.

Then, as shown in FIG. 17, the common electrode 34 and n + 1
The exposed region 57 of the connection portion 31 connecting the second anodizing electrode 29 and the lower electrode 32 is formed by an etching process using a RIE device, using the photosensitive resin 71 and the display electrode 51 as an etching mask. Remove by etching.

During this etching process, the photosensitive resin 71 and the display electrode
51, the first upper electrode 36, and the second upper electrode 38 serve as an etching mask.

Therefore, on the left side 72 of the first upper electrode 36 and the right side 73 of the second upper electrode 38, the lower electrode 32 and the insulating film are connected to the first upper electrode 36 and the second upper electrode 36. 38 and can be formed in a self-aligned manner.

Thus, by using the method of manufacturing the first substrate for forming the MIM element according to the third embodiment, it is possible to manufacture a non-linear resistance element having good symmetry.

Accordingly, the application of the DC component to the liquid crystal layer is eliminated, and the occurrence of an afterimage phenomenon which is a display problem can be prevented, and the display electrode 51 can be used as an etching mask.

Therefore, when the anodic oxidation electrodes 29 and 30 are separated from the lower electrode 32, the photosensitive resin 71 is applied to the first upper electrode 36.
And only on the upper surface of the second upper electrode 38 and the lower electrode 32 between the first upper electrode 36 and the second upper electrode 38.

Further, the entire area of the upper surfaces of the first upper electrode 36 and the second upper electrode 38 may not be covered with the photosensitive resin 71. Therefore, the positional accuracy of the region where the photosensitive resin 71 is formed can be reduced as compared with the related art.

Further, the connection part 31 remaining under the display electrode 51 is made of a metal film. Therefore, light can be shielded. Therefore, when used as a transmissive liquid crystal display device, the remaining connection portion 31 can be used as a light shielding film, and partial light shielding on the substrate on which the nonlinear resistance element is formed becomes possible.

Fourth Embodiment Next, a structure of a liquid crystal display device according to a fourth embodiment of the present invention and a method for manufacturing the same will be described with reference to FIGS.

First, the structure of the liquid crystal display according to the fourth embodiment of the present invention will be described.

A first active substrate for forming a non-linear resistance element
An electrode 3 for anodic oxidation, which is made of a tantalum (Ta) film containing nitrogen (N) as a metal film, a lower electrode 2, and the electrode 3 for anodic oxidation and the lower electrode 2 are connected on the substrate 1 of FIG. And a connection section 4 for performing the connection.

The anodizing electrode 3 has one end connected to the common electrode 6 and the other end connected to an input unit 7 for applying a signal from an external circuit to the nonlinear resistance element. Common electrode 6
Are used as electrodes when the insulating film 8 is formed by anodic oxidation.

Further, as shown in FIG. 20, an insulating film 8 made of a tantalum oxide (Ta ₂ O ₅ : N) film containing nitrogen formed by anodizing the lower electrode 2 is provided on the lower electrode 2. .

Further, a transparent conductive film is provided on the anodic oxidation electrode 3,
The signal electrode 9 is used. Then, a first upper electrode 10 connected to the signal electrode 9 is provided on the lower electrode 2, and a second upper electrode 11 connected to the display electrode 12 is provided on the lower electrode 2.

Note that the first upper electrode 10 and the second upper electrode 11 are provided on the lower electrode 2 with the insulating film 8 interposed therebetween.

Then, a first non-linear resistance element portion 13 is constituted by the lower electrode 2, the insulating film 8, and the first upper electrode 10, and the lower electrode 2
, The insulating film 8 and the second upper electrode 11 constitute a second nonlinear resistance element section 14.

Here, the signal electrode 9, the first upper electrode 10, the second upper electrode 11, and the display electrode 12 are all formed of a transparent conductive film, for example, an indium tin oxide (ITO) film.

Further, a signal electrode 9 for connecting to an external circuit is connected to the input unit 7.

Part of the display electrode 12 includes the anodizing electrode 3 and the lower electrode 2.
And an overlapping portion 15 which overlaps in a substantially L-shaped region of the connecting portion 4 for connecting the first and second portions.

A portion between the connection portion 4 between the lower electrode 2 and the display electrode 12 and a portion between the connection portion 4 between the anodizing electrode 3 and the display electrode 12 are removed to form an island-shaped lower electrode 2.

Further, a protective insulating film 85 is provided on the entire surface of each of these electrodes and the connection portion 4, and openings 80 and 81 are provided on the protective insulating film 85 so as to expose the overlapping portion 15 and the input portion 7.

In this embodiment, the first non-linear resistance element portion 13 and the second non-linear resistance element portion 14 provided in the region between the signal electrode 9 and the display electrode 12 are indium tin oxide film-tantalum oxide film containing nitrogen-nitrogen. And a second non-linear resistance element portion 14 composed of a “tantalum film containing nitrogen—a tantalum oxide film containing nitrogen—an indium tin oxide film”.

That is, looking at the current path from the signal electrode 9 to the display electrode 12, the first nonlinear resistance element portion 13 shows that the “indium tin oxide film—the tantalum oxide film containing nitrogen—the tantalum oxide film containing nitrogen” is the second. This flows to the “nitrogen-containing tantalum film—nitrogen-containing tantalum oxide film—indium tin oxide film” of the nonlinear resistance element portion 14.

Therefore, the connection of the nonlinear resistance element from the signal electrode 9 to the display electrode 12 and the connection of the nonlinear resistance element from the display electrode 12 to the signal electrode 9 have a symmetric structure.

Next, a method for manufacturing the liquid crystal display device according to the fourth embodiment will be described.

As shown in FIG. 18, a tantalum (Ta) film containing nitrogen (N) is formed on the first substrate 1 to a thickness of 250 nm over the entire surface by a sputtering method. Then, a photosensitive resin is formed on the tantalum film containing nitrogen.

After that, a photo-etching process using a photosensitive resin as an etching mask is performed, and an anodic oxidation electrode 3 and a lower electrode 2, both of which are made of a tantalum film containing nitrogen,
An anodizing electrode 3 and a connecting portion 4 connecting the lower electrode 2 are patterned. The etching of the tantalum film containing nitrogen is performed using an RIE apparatus.

The anodizing electrode 3 has one end connected to the common electrode 6 and the other end connected to an input unit 7 for applying a signal from an external circuit to the nonlinear resistance element unit.

Thereafter, an anodic oxidation process is performed using the common electrode 6 as an electrode to form an insulating film 8 made of a tantalum oxide (Ta ₂ O ₅ : N) film containing nitrogen on the surface of the lower electrode 2.

Next, indium tin oxide (ITO) is used as a transparent conductive film.
A film is formed with a thickness of 100 nm over the entire surface by a sputtering method. After that, a photosensitive resin is patterned on the indium tin oxide film.

Thereafter, the signal electrode 9 formed on the anodic oxidation electrode 3 and the first upper electrode 10 connected to the signal electrode 9 are formed by etching the indium tin oxide film.
A display electrode 12 and a second upper electrode 11 connected to the display electrode 12 are provided.

As a result, a first non-linear resistance element portion 13 is formed by the lower electrode 2, the insulating film 8, and the first upper electrode 10, and a second non-linear resistance element portion 13 is formed by the lower electrode 2, the insulating film 8, and the second upper electrode 11. Is formed.

The first nonlinear resistance element section 13 and the second nonlinear resistance element section 14 constitute a nonlinear resistance element.

Each of the first upper electrode 10, the second upper electrode 11, the signal electrode 9, and the display electrode 12 is formed of a transparent conductive film, for example, indium tin oxide (ITO) or a metal thin film.

Further, a signal electrode 9 for connecting to an external circuit is connected to the input unit 7.

The display electrode 12 has an overlapping portion 15 which is an area overlapping the connecting portion 4 connecting the anodizing electrode 3 and the lower electrode 2.
To form

Next, a tantalum oxide film is formed over the entire surface by a sputtering method to a thickness of 150 nm as a protective insulating film for the nonlinear resistance element.

Thereafter, a photosensitive resin is formed on the tantalum oxide film, and exposure and development are performed using a predetermined photomask.
A photosensitive resin having openings corresponding to the openings 80 and 81 is patterned.

Thereafter, using the photosensitive resin as an etching mask, the tantalum oxide film is subjected to an etching process, so that the overlapping portion 15 where the connecting portion 4 overlaps the display electrode 12 and the input portion 7 are overlapped.
The openings 80 and 81 are formed in the respective regions.

The etching of the tantalum oxide film is performed by using RIE equipment and using carbon tetrafluoride (CF ₄ ) as an etching gas in an amount of 200 to ₄₀₀ μm.
240 _SCCM and oxygen (O ₂ ) are mixed at a flow rate of 10 to 40 _SCCM , and the pressure is 4 to 12 × 10 ^-2 _torr and the power consumption is 0.2 to 0.5 kW / cm ² .

Then, as shown in FIG. 19, the photosensitive resin is used as an etching mask and the display electrode 12 is also used as an etching mask to connect the anodizing electrode 3 and the lower electrode 2 exposed in the opening 80. The part 4 is removed to form the island-shaped lower electrode 2.

In this embodiment, a protective insulating film 85 is formed in a region including the non-linear resistance element portion. And protective insulating film
Reference numeral 85 denotes an opening 81 and an opening 80 for cutting a connection between the lower electrode 2 and the anodizing electrode.

As described above, the connection portion 4 is cut by an etching process using the photosensitive resin for forming the opening 80 of the protective insulating film 85 and the display electrode 12 as an etching mask.

Therefore, as shown in FIG. 20, the lower electrode 2 and the insulating film 8 constituting the nonlinear resistance element have sides 86 that match the openings 80 of the protective insulating film 85.

Similarly, in the overlapping portion 15 where the display electrode 12 and the connection portion 4 overlap, the lower electrode 2 and the insulating film 8 are connected to the display electrode 12.
Has a side 87 that matches.

As is clear from the above description, the non-linear resistance element provided between the signal electrode 9 and the display electrode 12 is composed of the following: an indium tin oxide film-a tantalum oxide film containing nitrogen-a tantalum film containing nitrogen. It comprises a non-linear resistance element portion 13 and a second non-linear resistance element portion 14 composed of "a tantalum film containing nitrogen-a tantalum oxide film containing nitrogen-an indium tin oxide film".

Therefore, the connection of the nonlinear resistance element from the signal electrode 9 to the display electrode 12 and the connection of the nonlinear resistance element from the display electrode 12 to the signal electrode 9 have a symmetrical structure.

Therefore, by using the fourth embodiment, the non-linear resistance element has a symmetric current-voltage characteristic.

Therefore, the application of the DC voltage component to the liquid crystal layer during driving is almost eliminated, and the voltage waveform applied to the signal electrode can be made symmetrical.

As a result, the application of the DC voltage component between the signal electrode 9 and the display electrode 12 and between the signal electrode 9 and the counter electrode is eliminated, and it is possible to prevent the occurrence of an afterimage phenomenon which is a display problem.

Therefore, a liquid crystal display device having good display quality can be obtained. Further, by forming the protective insulating film 85 on the non-linear resistance element portion, the change with time of the non-linear resistance element can be reduced.

The opening 81 is provided because the protection insulating film 85 of the input section 7 needs to be removed in order to connect to an external circuit by forming the protection insulating film 85.

Further, since it is not necessary to newly form an etching mask for cutting the connection portion 4 between the lower electrode 2 and the anodic oxidation electrode 3, the step of cutting and separating becomes very simple.

[Other embodiments]

Next, referring to FIG. 21 and FIG. 22, the first
A liquid crystal display device according to an embodiment different from the fourth embodiment will be described.

The difference between the configurations shown in FIGS. 21 and 22 and the configurations of the liquid crystal display devices of the first to fourth embodiments is the number of upper electrodes.

That is, in the first to fourth embodiments, the upper electrode is 2
In the embodiment shown in FIGS. 21 and 22, the first upper electrode 91, the second upper electrode 92, and the third upper electrode 93 are provided.
And the four upper electrodes of the fourth upper electrode 94 are provided so as to intersect on the lower electrode 2.

Then, in the embodiment shown in FIG. 21, the first upper electrode
91 and the third upper electrode 93 are connected to the signal electrode 9 and the second
The upper electrode 92 and the fourth upper electrode 94 are connected to the display electrode 12.

That is, in this configuration, the first upper electrode 91 and the third upper electrode 93 are connected in parallel, and the second upper electrode 92 and the fourth upper electrode 94 are also connected in parallel. Then, those connected in parallel are connected in series.

In the liquid crystal display device shown in FIG. 21, the application of the DC voltage component caused by the asymmetric current-voltage characteristic, which is the above-described effect, is reduced, and a display without an afterimage phenomenon is obtained. This has the effect of making it possible to compensate for the disconnection defect.

In addition, the configuration shown in FIG.
The upper electrode 92, the third upper electrode 93, and the fourth upper electrode 94 are connected in series.

In the liquid crystal display device shown in FIG. 22, the application of the DC voltage component caused by the asymmetric current-voltage characteristic, which is the above-described effect, is reduced, and a display free from an afterimage phenomenon is obtained. There is also an effect that the thickness of the insulating film in the element portion can be reduced.

Further, in FIGS. 21 and 22, the embodiment in which four upper electrodes are provided has been described, but six or more upper electrodes may be provided. That is, an even number of upper electrodes may be provided. Note that the manufacturing method of the liquid crystal display device may apply the manufacturing methods of the first to fourth embodiments.

In the embodiment of the present invention described above, an example was described in which indium tin oxide (ITO) was used as the transparent conductive film. However, indium oxide (In ₂ O ₃ ), tin oxide (Sn
O ₂ ) or an oxide such as zinc oxide (ZnO) may be used.

Further, although an example using tantalum or tantalum containing nitrogen as a material of the lower electrode has been described, a metal film such as carbon or silicon or tantalum containing niobium or aluminum may be used.

Further, in the second embodiment and the third embodiment,
Although an example using a chromium film as the upper electrode has been described, other than the chromium film, titanium, tungsten, titanium silicide, tungsten silicide, a chromium film containing nitrogen, or the like can also be used.

Fifth Embodiment Next, a fifth embodiment of the present invention will be described with reference to FIGS.

FIG. 23 is a plan view showing a partial region of a first substrate forming a non-linear resistance element (MIM element) of a liquid crystal display according to a fifth embodiment of the present invention, and FIG.
It is sectional drawing which follows the XXIV line. First, the configuration of the liquid crystal display device of this embodiment will be described with reference to these drawings.

On a transparent substrate 1 which is an active substrate for forming a non-linear resistance element portion, tantalum (T
a) An anodic oxidation electrode 3 made of a film, a lower electrode 2, and a connection portion 4 for connecting the two anodic oxidation electrodes 3 to two lower electrodes 2, 2 are provided. The connecting portion 4 is a T-shaped portion that forms a T-shaped overlapping portion 15 below a display electrode 95 described later.
4a.

The anodizing electrode 3 has one end connected to the common electrode 6 and the other end connected to an input unit 7 for applying a signal from an external circuit to the nonlinear resistance element unit. This common electrode 6
Is used as an electrode when the insulating film 8 is formed on the surface of the lower electrode 2 by anodic oxidation.

Here, the electrode 3 for anodic oxidation, the overlapping portion 15 and the lower electrode 2
The arrangement of the connection section 4 will be described.

These positional relationships are as shown in FIG.
In a T-shaped overlapping portion 15 provided below 95, one side of the T-shaped portion 4a is connected to the anodizing electrode 3 via the connecting portion 4, and two sides orthogonal to this side are respectively connected via the connecting portion 4. Connect to lower electrode 2. Further, the plurality of anodizing electrodes 3 are mutually connected by a common electrode 6 outside.

In a configuration used in an actual liquid crystal display device, a portion between the signal electrode 9 and the display electrode 95 of the connection portion 4 and a portion between the T-shaped portion 4a and the two lower electrodes 2 are cut.

The connection electrode 4 at a portion between the signal electrode 9 and the display electrode 95 is
The display electrode 95 has substantially the same side as the display electrode 95, and the connection electrode 4 between the T-shaped overlapping portion 15 and the two lower electrodes 2 also has substantially the same side as the display electrode 95. Further, the common electrode 6 connected to the signal electrode 9 is also disconnected from the signal electrode 9.

That is, the connection electrode 4 in a portion between the anodizing electrode 3 corresponding to the signal electrode 9 and the display electrode 95 provided in the overlapping portion 15.
The connecting electrode 4 between the T-shaped overlapping portion 15 and the two lower electrodes 2 (both are indicated by two-dot chain lines), and the area indicated by the two-dot chain line of the common electrode 6 are the liquid crystal. 9 shows an intermediate state of the manufacturing process of the display device.

Further, the display electrode for the signal electrode 9 is overlapped with the overlapping portion 15.
And the display electrodes 96 having no overlapping portion 15 are alternately arranged.

An insulating film 8 made of a tantalum oxide (Ta ₂ O ₅ ) film formed by anodizing the lower electrode 2 is provided on the surface of the lower electrode 2.

Then, a transparent conductive film is provided on the anodizing electrode 3 to form the signal electrode 9. A first upper electrode 10 connected to the signal electrode 9 and a second upper electrode 11 connected to the display electrode 95
Are provided on the lower electrode 2 so as to intersect with the lower electrode 2.

The first upper electrode 10 and the second upper electrode 11 are provided on the island-shaped lower electrode 2 via an insulating film 8.

Then, a first non-linear resistance element portion 13 is constituted by the lower electrode 2, the insulating film 8, and the first upper electrode 10, and the lower electrode 2
, The insulating film 8 and the second upper electrode 11 constitute a second nonlinear resistance element section 14.

Here, the signal electrode 9, the first upper electrode 10, the second upper electrode 11, and the display electrode 95 are all formed of a transparent conductive film, for example, an indium tin oxide (ITO) film.

Further, a signal electrode 9 for connecting to an external circuit is connected to the input unit 7.

Here, the first nonlinear resistance element portion 13 and the second nonlinear resistance element portion 14 provided in the region between the signal electrode 9 and the display electrode 95 or 96 are “indium tin oxide film-tantalum oxide film-tantalum film”. A first non-linear resistance element portion 13 comprising:
"Tantalum film-Tantalum oxide film-Indium tin oxide film"
And a second non-linear resistance element portion.

That is, looking at the current path from the signal electrode 9 to the display electrode 95 or 96, the “indium tin oxide film-tantalum oxide film-tantalum film” of the first nonlinear resistance element portion 13 shows
It flows to the “tantalum film-tantalum oxide film-indium tin oxide film” of the second nonlinear resistance element portion 14.

Therefore, the connection of the non-linear resistance element portion from the signal electrode 9 to the display electrode 95 or 96 and the display electrode 95 or 96
And the connection of the nonlinear resistance element to the signal electrode 9 has a symmetrical structure.

As is apparent from the above description, the T-shaped portion of the connection portion 4
A display electrode 95 having an overlapping portion 15 with 4a, and the overlapping portion
Since the display electrodes 96 having no 15 can be provided alternately, the ratio of the overlapping portions 15 can be reduced.

Therefore, the liquid crystal display device of this embodiment can perform brighter display as compared with the case where the overlapping portion 15 exists in each display electrode.

Sixth Embodiment Next, a sixth embodiment of the present invention will be described with reference to FIGS. 25 and 26. FIG. 25 is a plan view showing a partial region of a substrate on which a non-linear resistance element (MIM element) of a liquid crystal display according to a sixth embodiment of the present invention is formed.
FIG. 26 is a sectional view taken along the line XXVI-XXVI.

In this liquid crystal display device, one pixel portion is constituted by four display electrodes 95, 95, 96, 96. By adopting this method, even if a defect occurs in the nonlinear resistance element, it does not become a defect in the pixel portion if the other three display electrodes are functioning normally.

Further, the “current−
The viewing angle characteristics of the liquid crystal display device can be improved by using a method of giving a difference in the "voltage characteristics", for example, by setting the area of the nonlinear resistance element different for each display electrode.

On a substrate 1 which is an active substrate for forming a non-linear resistance element, aluminum (Al) is used as a metal film.
An anodizing electrode 3 made of a film, a lower electrode 2, and a connecting portion 4 having a T-shaped portion 4 a connected to the anodizing electrode 3 and two lower electrodes 2 are provided.

The connecting portion 4 and the T-shaped portion 4a are provided below the display electrode 95 with a T
A mold overlap 15 is formed. One side of the T-shaped part 4a is connected to the anodic oxidation electrode 3 via the connection part 4, and the other side is
The lower electrodes 2 are connected to the lower electrodes 2 via connection portions 4.

The anodizing electrode 3 has one end connected to the common electrode 6 and the other end connected to an input unit 7 for applying a signal from an external circuit to the nonlinear resistance element unit. The common electrode 6 is used as an electrode when the insulating film 8 is formed on the surface of the lower electrode 2 by anodic oxidation.

The configuration used in an actual liquid crystal display device is as follows: a portion of the connection electrode 4 between the signal electrode 9 and the display electrode 95; and a portion between the T-shaped overlapping portion 15 and the two lower electrodes 2 (see FIG. 25). (Indicated by a virtual line), the connection electrode 4 at the portion between the signal electrode 9 and the display electrode 95 has substantially the same side as the display electrode 95, and has a T-shaped overlapping portion 15 and two lower portions. The connection electrodes 4 between the electrodes 2 also have substantially the same sides as the display electrodes 95. Further, the common electrode 6 (shown by a virtual line in FIG. 25) connected to the signal electrode 9 is also disconnected from the signal electrode 9.

That is, the connection electrode 4 at a portion between the anodizing electrode 3 corresponding to the signal electrode 9 and the display electrode 95 having the overlapping portion 15.
The area shown by the imaginary lines of the connection electrode 4 between the T-shaped overlapping portion 15 and the two lower electrodes 2 and the common electrode 6 shows an intermediate state in the manufacturing process of the liquid crystal display device. ing.

Further, the display electrodes 95 and 96 for the signal electrode 9 are a display electrode 95 having the overlapping portion 15 and a display electrode having no overlapping portion 15.
96 are alternately arranged. And, symmetrically with the signal electrode 9,
Display electrodes 95 each having a plurality of display electrodes and having an overlapping portion 15.
And the display electrode 96 without the overlapping portion 15 intersects.
The two display electrodes 95, 95 and 96, 96 which cross each other
One pixel portion is constituted by the four display electrodes.

Further, an insulating film 8 made of a tantalum oxide (Ta ₂ O ₅ ) film formed by anodizing the lower electrode 2 is provided on the surface of the lower electrode 2.

A thin metal film is provided on the anodizing electrode 3 to form a signal electrode 9. Then, a first upper electrode 10 connected to the signal electrode 9 is provided on the lower electrode 2, and further a display electrode
A second upper electrode 11 connected to 95 and 96 is provided on the lower electrode 2.

The first upper electrode 10 and the second upper electrode 11 are provided on the island-shaped lower electrode 2 via an insulating film 8.

Then, a first non-linear resistance element portion 13 is constituted by the lower electrode 2, the insulating film 8, and the first upper electrode 10, and the lower electrode 2
, The insulating film 8 and the second upper electrode 11 constitute a second nonlinear resistance element section 14.

Here, the signal electrode 9, the first upper electrode 10, the second upper electrode 11, and the display electrodes 95 and 96 are all formed of a thin metal film, for example, a thin niobium (Nb) film.

Further, a signal electrode 9 for connecting to an external circuit is connected to the input unit 7.

Here, the first non-linear resistance element portion 13 and the second non-linear resistance element portion 14 provided in the region between the signal electrode 9 and the display electrode 95 or 96 are formed from “thin film niobium film-tantalum oxide film-tantalum film”. A first non-linear resistance element portion 13 and a second non-linear resistance element portion 13 composed of a "tantalum film-tantalum oxide film-thin niobium film".
Of the non-linear resistance element section 14.

That is, looking at the current path from the signal electrode 9 to the display electrode 95 or 96, the “non-thin niobium film-tantalum oxide film-tantalum film” of the first nonlinear resistance element section 13 shows the second nonlinear resistance element section 14 Tantalum film-Tantalum oxide film-
To a "thin niobium film".

Therefore, the connection of the non-linear resistance element portion from the signal electrode 9 to the display electrode 95 or 96 and the display electrode 95 or 96
And the connection of the nonlinear resistance element to the signal electrode 9 has a symmetrical structure.

As is apparent from this description, the display electrode 95 having the T-shaped overlapping portion 15 and the display electrode 95 having no overlapping portion 15 are provided.
96 can be arranged alternately with respect to the signal electrode 9 so as to intersect with each other, and the overlapping portion 15 can be made symmetrical with respect to the concentrated point.

For this reason, the liquid crystal display device of the present invention provides a display electrode 96 having no overlapping portion 15 as compared with the case where the overlapping portion 15 exists in each display electrode, so that bright display can be performed.

Seventh Embodiment Next, a liquid crystal display device according to a seventh embodiment of the present invention will be described with reference to FIGS. 27 and 28. FIG. 27 is a plan view showing a partial region of a substrate forming a liquid crystal display device (MIM element) of the liquid crystal display device according to this embodiment, and FIG. 28 is a cross-sectional view taken along the line XXVIII-XXVIII. .

In this embodiment, a case will be described in which one nonlinear resistance element 13 is provided for one display electrode 100.

First, on a substrate 1 which is an active substrate for forming a non-linear resistance element portion, tantalum (T
a) Anodizing electrode 3 made of a film and anodizing electrode 3
And has a lower electrode 2 projecting from the lower electrode. The anodizing electrode 3 has an overlapping portion 101 below the adjacent display electrode 100.

Further, on the surface of the lower electrode 2, the lower electrode 2
Is provided with an insulating film 8 made of a tantalum oxide (Ta ₂ O ₅ ) film formed by performing anodic oxidation.

In addition, a transparent conductive film is provided on the anodizing electrode 3 to serve as a signal electrode 9. Then, the upper electrode 10 connected to the display electrode 100 is provided on the lower electrode 2, and the nonlinear resistance element 13 is formed by the upper electrode 10 and the nonlinear resistance layer including the lower electrode 2 and the insulating film 8.

Here, the signal electrode 9, the upper electrode 10, and the display electrode 100 are all formed of a transparent conductive film, for example, an indium tin oxide (ITO) film.

Further, a signal electrode 9 for connecting to an external circuit is provided.
Is connected to the input unit 7.

Here, the configuration of the anodizing electrode 3 will be described. The anodizing electrode 3 has one end connected to the common electrode 6 and the other end connected to an input unit 7 for applying a signal from an external circuit to the nonlinear resistance element unit. The common electrode 6 is used as an electrode when an insulating film 8 is formed on the surface of the lower electrode 2 by anodizing. Also, the anodizing electrode 3
Before the anodic oxidation, the lower part of the signal electrode 9 and
The overlapping portion 101 and the signal electrode 9 are provided below the adjacent display electrode 100.
Of the anodizing electrode 3 indicated by a broken line is W1 because the connecting portion 4 includes a portion connecting the lower portion of the anodizing electrode 101 and a portion connecting the overlapping portion 101 and the display electrode 100 parallel to the signal electrode 9. .

The configuration used in the actual liquid crystal display device is such that a portion connecting the overlapping portion 101 below the signal electrode 9 in the connecting portion 4 and a portion connecting the display electrode 100 parallel to the signal electrode 9 are cut off. The wiring width of the display device in use is W2. (W2 <W1). Further, the signal electrode 9 and each display electrode 10
0 is separated and the signal electrode 9 is connected via the nonlinear resistance element 13.

Further, the connection portions 4 connecting the respective display electrodes 100 are separated into isolated display electrodes 100.

The common electrode 6 connected to the signal electrode 9 is also disconnected from the signal electrode 9.

As described above, before the anodizing electrode 3 is anodized, the overlapping portion 101 is provided below the display electrode 100, the width W1 of the anodizing electrode 3 is increased, and the film quality and thickness of the anodized film are increased. It is possible to improve the uniformity of the film and to form a high-performance film in a short time.

Therefore, by providing the overlapping portion 101 on each display electrode 100, the width of the anodic oxidation electrode 3 used when actually using the liquid crystal display device can be reduced, so that a bright display can be performed.

Further, a part of the overlapping portion 101 is a light shielding film (black matrix) for improving the display quality of the liquid crystal display device.
By using as, the alignment accuracy between the black matrix and the display electrode 100 can be improved.

Further, when the lower electrode, which is a component of the nonlinear resistance element, is separated from the anodizing electrode, the photosensitive resin and the display electrode can be used as an etching mask. For this reason, the positioning accuracy between the photosensitive resin covering the connection portion and the non-linear resistance element can be reduced.

As a result, the display quality of the liquid crystal display device can be easily improved. In particular, the image sticking phenomenon can be improved to a level not inferior to that of the three-terminal system.

Further, by covering the non-linear resistance element with a protective insulating film, deterioration of the non-linear resistance element can be reduced. Therefore, the reliability of the liquid crystal display device can be improved.

INDUSTRIAL APPLICABILITY As described above, by using the configuration of the liquid crystal display device having the non-linear resistance element according to the present invention and the method of manufacturing the same, the asymmetric current-voltage characteristic due to the applied voltage of the non-linear resistance element is made symmetric. In addition, the DC voltage component to the liquid crystal layer can be reduced to prevent the image display quality of the liquid crystal from deteriorating, the contrast from deteriorating, and the occurrence of an image sticking phenomenon such as a flicker phenomenon and an afterimage phenomenon.

Further, when the lower electrode, which is a component of the nonlinear resistance element, is separated from the anodizing electrode, the photosensitive resin and the display electrode can be used as an etching mask. Therefore, the positioning accuracy between the photosensitive resin that covers the connection portion and the nonlinear resistance element can be reduced.

As a result, the display quality of the liquid crystal display device can be easily improved. In particular, the image sticking phenomenon can be improved to a level not inferior to that of the three-terminal system.

Further, by covering the non-linear resistance element with a protective insulating film, deterioration of the non-linear resistance element can be reduced. Therefore, the reliability of the liquid crystal display device can be improved.

Therefore, by applying the present invention to a liquid crystal display device that is diversified into various portable or small electronic devices, the display quality can be improved, and the liquid crystal display device can be manufactured efficiently.

Claims (10)

(57) [Claims] A metal film is formed on a substrate, and the metal film is patterned by photoetching to form a plurality of anodic oxidation electrodes, a common electrode connecting the anodic oxidation electrodes, and a non-linear resistance element. Forming a lower electrode of the portion and a connecting portion connecting the lower electrode and the anodizing electrode; and forming the anodizing electrode connected to the common electrode integrally with the common electrode as an anode. Forming an insulating film by performing anodic oxidation on the electrode, the connection portion, and the lower electrode; forming a transparent conductive film on the insulating film and on the substrate;
The transparent conductive film is patterned by a photoetching process, and each display electrode on the substrate is formed so as to provide an overlapping portion covering a part of the connection portion, and a signal electrode is formed on each of the anodizing electrodes. Forming a gap with the lower electrode, forming a first upper electrode connected to the signal electrode and a second upper electrode connected to the display electrode on each of the lower electrodes; Forming a photosensitive resin in a region covering the lower electrode and the first and second upper electrodes; and performing an etching process using the photosensitive resin, the display electrode, and the signal electrode as an etching mask. The connection portion of the multilayer structure composed of the metal film and the insulating film which is an anodic oxide film formed thereon is completely etched to the surface of the substrate, and the display electrode and the signal electrode are duplicated. The lower electrode is separated from the anodic oxidation electrode in the lower layer of the signal electrode, the overlapping portion of the connecting portion in the lower layer of the display electrode, and the lower electrode, and the lower electrode is islanded. The lower electrode, the insulating film, and the first and second upper electrodes form first and second non-linear resistance element portions, and connect the plurality of anodic oxidation electrodes. Etching the electrodes using the signal electrodes as an etching mask to electrically separate the anodic oxidation electrodes. A method for manufacturing a liquid crystal display device, comprising: A metal film is formed on the substrate, and the metal film is patterned by photoetching to form a plurality of anodizing electrodes, a common electrode connecting the anodizing electrodes, and a non-linear resistance element. Forming a lower electrode of the portion and a connecting portion connecting the lower electrode and the anodizing electrode; and forming each of the anodizing portions integrally connected to the common electrode using the common electrode as an anode. Forming an insulating film by performing anodic oxidation on the electrode, the connection portion, and the lower electrode; forming a metal film on the insulating film and on the substrate; and patterning the metal film by photoetching. ,
A signal electrode is formed on the anodizing electrode, and a first electrode connected to the signal electrode on each of the lower electrodes.
Forming an upper electrode and a second upper electrode having a pad portion, forming a transparent conductive film on the substrate including the insulating film and the pad portion, and subjecting the transparent conductive film to a photoetching process. Patterning, forming a display electrode electrically separated from the signal electrode and the lower electrode so as to provide an overlapping portion covering a part of the connection portion and the pad portion; A step of forming a photosensitive resin in a region covering the upper electrode of Step 2 and an etching process using the photosensitive resin, a display electrode, and a signal electrode made of different materials as an etching mask, thereby forming The connection portion of the multilayer structure including the insulating film which is an anodic oxide film formed on the substrate is completely etched to the surface of the substrate, and the display electrode and the signal electrode are formed. The shape is self-aligned with the number of sides, the anodizing electrode under the signal electrode, the overlapping portion under the display electrode of the connection portion and the lower electrode are separated from each other, and the lower electrode is Isolated in an island shape, the lower electrode, the insulating film, and the first and second upper electrodes form first and second non-linear resistance element portions and connect the plurality of anodizing electrodes. Etching the common electrode using the signal electrode as an etching mask to electrically separate the anodic oxidation electrodes. A method for manufacturing a liquid crystal display device, comprising: 3. A metal film is formed on a substrate, and the metal film is patterned by photoetching to form a plurality of anodizing electrodes, a common electrode connecting the anodizing electrodes, and a non-linear resistance element. Forming a lower electrode of the portion and a connecting portion connecting the lower electrode and the anodizing electrode; and forming each of the anodizing portions integrally connected to the common electrode using the common electrode as an anode. Forming an insulating film by performing anodic oxidation on the electrode, the connection portion, and the lower electrode; forming a metal film on the insulating film and on the substrate; and patterning the metal film by photoetching. ,
A signal electrode is formed on the anodizing electrode, and a first electrode connected to the signal electrode on each of the lower electrodes.
Forming an upper electrode and a second upper electrode having a pad portion, forming a transparent conductive film on the substrate including the insulating film and the pad portion, and subjecting the transparent conductive film to a photoetching process. Patterning to form a display electrode which is electrically separated from the signal electrode and the lower electrode so as to provide an overlapping portion covering a part of the connection portion and the pad portion; and the first and second upper portions. A step of forming a photosensitive resin in a region covering approximately half of each of the opposing sides of the electrode on the lower electrode and a region covering the lower electrode therebetween; and forming the photosensitive resin, the display electrode, and the second electrode made of different materials, respectively. 1, a multilayer structure composed of the metal film and an insulating film that is an anodic oxide film formed thereon by an etching process using the second upper electrode and the signal electrode as an etching mask. The connection portion and the lower electrode are completely etched down to the surface of the substrate, so that the connection portion is shaped so as to be self-aligned with a plurality of sides of the display electrode and the signal electrode, and the lower electrode is formed of the first and second electrodes. In a shape that is self-aligned with each outer side of the upper electrode, an anodizing electrode under the signal electrode and an overlapping portion under the display electrode of the connection portion and the lower electrode are separated from each other, The first and second upper electrodes are formed by the lower electrode, the insulating film, and the first and second upper electrodes.
A second non-linear resistance element portion is formed, and a common electrode connecting the plurality of anodizing electrodes is removed by etching using the signal electrode as an etching mask to electrically separate the anodizing electrodes. A method for manufacturing a liquid crystal display device, comprising: 4. A method of forming a metal film on a substrate, patterning the metal film by photoetching, forming a plurality of anodizing electrodes, a common electrode connecting the anodizing electrodes, and a non-linear resistance element. Forming a lower electrode of the portion and a connecting portion connecting the lower electrode and the anodizing electrode; and forming each of the anodizing portions integrally connected to the common electrode using the common electrode as an anode. Forming an insulating film by performing anodic oxidation on the electrode, the connection portion, and the lower electrode; forming a transparent conductive film on the insulating film and on the substrate;
The transparent conductive film is patterned by a photoetching process, and each display electrode is formed on the substrate so as to provide an overlapping portion covering a part of the connection portion, and a signal electrode is formed on each of the anodizing electrodes. Forming a gap with the lower electrode, forming a first upper electrode connected to the signal electrode and a second upper electrode connected to the display electrode on each of the lower electrodes; After each of the steps, a protective insulating film is formed on the entire surface of the substrate including the electrodes and the connecting portions, and a photo-etching process is performed to form the display electrodes on the connecting portions of the protective insulating film. Forming an opening in a region including an overlapping portion with the display electrode and a portion exposed from the display electrode; and etching the protective insulating film and the display electrode and the signal electrode in each of the openings. The etching process used as a mask completely etches the connection portion of the multilayer structure including the metal film and the insulating film which is an anodic oxide film formed thereon up to the surface of the substrate, so that the display electrode and the signal are The shape is self-aligned with multiple sides of the electrode,
The anodizing electrode under the signal electrode and the overlapping portion under the display electrode of the connection portion and the lower electrode are separated from each other, and the lower electrode is isolated in an island shape. Forming a first and a second non-linear resistance element portion by using the insulating film and the first and second upper electrodes. 5. A liquid crystal display device having display electrodes arranged in a matrix on a substrate, wherein the display electrodes serve as pixel portions, wherein an anodizing electrode made of a metal film and an island-like electrode are formed on the substrate. A lower electrode, an insulating film provided on the surface of the metal film,
Two upper electrodes made of a transparent conductive film provided on the lower electrode via an insulating film, a display electrode made of a transparent conductive film, and a signal electrode made of a metal film or a metal film and a transparent conductive film, The two upper electrodes intersect with the lower electrode, and the two upper electrodes, the insulating film, and the lower electrode constitute two nonlinear resistance element sections, and the two upper electrodes constituting the nonlinear resistance element section One of the electrodes is connected to the signal electrode, the other is connected to the display electrode, and the display electrode forming the pixel portion has a two-layer film of the same metal film and insulating film as the lower electrode remaining therebelow. A liquid crystal display device comprising two types of display electrodes, a display electrode having an overlap portion and a display electrode having no overlap portion therebelow. 6. A liquid crystal display device having display electrodes arranged in a matrix on a substrate and forming one pixel portion by a plurality of display electrodes, wherein an anodizing electrode made of a metal film is formed on the substrate. And an island-shaped lower electrode; an insulating film provided on the surface of the metal film; two upper electrodes made of a transparent conductive film provided on the lower electrode via an insulating film; and a display electrode made of a transparent conductive film And a signal electrode composed of a metal film or a metal film and a transparent conductive film. The two upper electrodes intersect the lower electrode, and the two upper electrodes, the insulating film and the lower electrode form two One of the two upper electrodes forming the nonlinear resistance element portion is connected to the signal electrode, the other is connected to the display electrode, and the display electrode forming the one pixel portion But at the bottom A display electrode having an overlapping portion in which a two-layer film of the same metal film and the insulating film as the lower electrode remains; and a display electrode having no overlapping portion below the display electrode. Characteristic liquid crystal display device. 7. A liquid crystal display device having display electrodes arranged in a matrix on a substrate and forming one pixel portion by a plurality of display electrodes, wherein an anodizing electrode made of a metal film on the substrate. And an island-shaped lower electrode, an insulating film provided on the surface of the metal film,
Two upper electrodes made of a transparent conductive film provided on the lower electrode via an insulating film, a display electrode made of a transparent conductive film, and a signal electrode made of a metal film or a metal film and a transparent conductive film, The two upper electrodes intersect with the lower electrode, and the two upper electrodes, the insulating film, and the lower electrode constitute two nonlinear resistance element sections, and the two upper electrodes constituting the nonlinear resistance element section One of the electrodes is connected to the signal electrode, the other is connected to the display electrode, and the display electrode forming the one pixel portion has a two-layered film under the same metal film as the lower electrode and the insulating film. Are composed of two types of display electrodes: a display electrode having an overlapped portion where the remaining portion remains, and a display electrode having no overlapped portion under the display electrode. You are A liquid crystal display device characterized by the following. 8. The method for manufacturing a liquid crystal display device according to claim 1, wherein the step of forming the display electrode, the signal electrode, and the first and second upper electrodes comprises the steps of: A method for manufacturing a liquid crystal display device, comprising: forming the display electrode so as to provide an overlapping portion that covers a part of a connection portion that connects a lower electrode of a non-linear resistance element portion and the anodizing electrode. 9. The method for manufacturing a liquid crystal display device according to claim 2, wherein a metal film is formed on the substrate, and the metal film is patterned by photoetching to form a plurality of anodizing electrodes. Forming a common electrode connecting the respective anodizing electrodes, a lower electrode of the non-linear resistance element portion, and a connecting portion connecting the lower electrode and the anodizing electrode; In the step of forming the display electrode integrally with an anodizing electrode formed under a signal electrode in a row or a column different from the signal electrode connected to the non-linear resistance element portion of the pixel, A method of manufacturing a liquid crystal display device, comprising: forming the display electrode so as to provide an overlapping portion that covers a part of a connection portion connected to a lower electrode of a non-linear resistance element portion of a pixel. 10. The method for manufacturing a liquid crystal display device according to claim 3, wherein a metal film is formed on the substrate, and the metal film is patterned by photoetching to form a plurality of anodizing electrodes. In the step of forming a common electrode connecting the respective anodizing electrodes, a lower electrode of the non-linear resistance element portion, and a connecting portion connecting the lower electrode and the anodizing electrode, the connecting portion is formed by: In the step of forming the display electrode integrally with an anodizing electrode formed under a signal electrode in a row or a column different from the signal electrode connected to the non-linear resistance element portion of the pixel, A method of manufacturing a liquid crystal display device, comprising: forming the display electrode so as to provide an overlapping portion that covers a part of a connection portion connected to a lower electrode of a non-linear resistance element portion of a pixel.