WO1996030801A1

WO1996030801A1 - Liquid crystal display

Info

Publication number: WO1996030801A1
Application number: PCT/JP1995/000590
Authority: WO
Inventors: Kazuhiro Ogawa; Kikuo Ono; Nobutake Konishi
Original assignee: Hitachi, Ltd.
Priority date: 1995-03-29
Filing date: 1995-03-29
Publication date: 1996-10-03

Abstract

On an active matrix substrate constituting a liquid crystal display, protective films which are separated from each other in a scanning wiring area between adjacent signal lines are formed to protect video signal lines and a thin film transistor. The protective films are separated from each other on picture element electrodes. The scanning wires are coated with insulating films and the insulating films are exposed from a liquid crystal layer in the scanning wire area. The scanning wiring constitutes the gate electrode of the thin film transistor and a laminated gate insulating film is formed on the gate electrode.

Description

Specification

Liquid crystal display technology

The present invention relates to a structure of an active matrix type liquid crystal display device having a thin film transistor used as a display device for image information and character information of an office automation apparatus or the like as a switching element.冃 JP, &. Fer

An active matrix substrate equipped with a thin-film transistor (hereafter abbreviated as FT) as a switching element is protected on the top layer to prevent electrolytic corrosion of the metal material used for wiring and to stabilize the electrical conductivity of the TF. A film is formed. Conventionally, the protective film is formed on the entire surface of the image display area, and has a structure in which only the terminal portions of the scanning wiring and the video signal wiring are removed to connect an external circuit. However, if a protective film is present on the pixel electrode, electric charges are accumulated in the protective film during an image display period, and there is a problem that an afterimage is easily generated. Therefore, a structure in which the protective film on the pixel electrode is removed is applied for the purpose of reducing the afterimage. As an example of this, the Technical Report of the Institute of Television Engineers of Japan, August 1998, pp. 1-6 (ITE Technical Report Vol. 12. O. 32. Pp. 1-6, ID '8 8-70 (Aug. 1 988)))). In this example, the opening of the protective film on the pixel electrode is smaller than the pixel electrode pattern, and covers all wiring.

One of the issues with liquid crystal display devices is improving the production yield. The main defects in the manufacturing process of the active matrix substrate are disconnection of scanning wiring and video signal wiring, short-circuiting of scanning wiring and video signal wiring, short-circuiting between video signal wirings, and point defects of display pixels. Is this point defect external? The image cannot be controlled by the voltage supplied from the camera, and it always lights up in one of RGB, or refers to a defect in a pixel unit that always displays black or white.

The present invention pays particular attention to short-circuit defects between video signal lines and point defects. There are several causes of short-circuit defects and point defect defects between video signal wirings. Among them, a large percentage are caused by amorphous silicon (hereinafter abbreviated as a-S i) and patterning defects of video signal wirings. This is mainly caused by adhesion of foreign matter before and after resist coating and defective development after exposure. As a measure to reduce point defect defects, the defect rate can be reduced to some extent by devising the structure of the active matrix substrate, such as increasing the distance between the pixel electrode and the video signal wiring. However, patterning defects of a-Si and video signal wiring occur with a substantially constant probability due to the cleanliness of the production line and the like. It is difficult to reduce the defects caused by the defect.

An object of the present invention is to provide a liquid crystal display device capable of reducing short circuit defects between video signal lines and point defect defects. Disclosure of the invention

On the active matrix substrate constituting the liquid crystal display device of the present invention, a protective film for protecting the video signal wiring and the thin film transistor, which is separated on the scanning wiring area between adjacent signal wirings, is formed. .

The protective film is also separated on the pixel electrode.

The scanning wiring is covered with an insulating film, and the coated insulating film is exposed to the liquid crystal layer on a scanning wiring region between signal wirings where the protective film is separated. The scanning wiring constitutes a gate electrode of the thin film transistor, and a gate insulating film having a ridge layer is formed on the gate electrode.

According to the embodiment of the present invention, one end of the pixel electrode has a protective film separated from the scanning electrode. The additional capacitance is formed by the extended portion extending over the scan wiring region, the extended portion, the scanning line formed below the portion, and the insulating layer covering the scanning line.

Further, according to an embodiment of the present invention, there is provided an additional capacitor upper electrode connected to one end of the pixel electrode and formed on the scanning wiring region from which the protective film is separated. An additional capacitance is formed by the scanning wiring formed below this portion and the insulating layer covered by the scanning wiring.

When short-circuit defects and point defect defects between video signal lines occur due to poor patterning of a-Si, the occurrence locations are extremely large on the scanning lines. Since the a-Si pattern exists at the TFT section or at the intersection of the scanning wiring and the video signal wiring, it is formed on or near the scanning wiring. Therefore, more defective patterns of a-Si connected to the video signal wiring occur on the scanning wiring than on the pixel electrode.

According to the present invention, the protective film has an opening crossing at least a part of the scanning wiring of each pixel. The protective film in the image display area is separated between the video signal wirings. This has a structure in which the video signal wiring and the TFT section are covered with a protective film, and the pixel electrodes and the scanning wiring are opened in a substantially linear shape. With such a configuration, the defective pattern of a—Si remaining on the scanning wiring can be separated, and a short-circuit failure and a point defect failure between the video signal wirings can be relieved.

The above configuration is realized by, for example, etching a-Si again after processing the protective film. The case where the protective film is a silicon nitride Ya silicon oxide, by Etsuchin grayed said protective film by SF _S-based dry etching method, can be removed failure pattern of self-aligned manner a- S i. In this case, it is desirable to cover the terminals with ITO (indium oxide monoxide film) so that they do not adversely affect the re-etching of a-Si. New

As another cause of the short circuit failure between the video signal wirings, there is one in which adjacent video signal wirings are connected due to poor patterning of the video signal wirings. By applying the same etching process as when processing the video signal wiring again after processing the protective film when applying the present invention, a defective pattern of the video signal wiring can be removed, and a short-circuit failure between the video signal wirings can be relieved. Further, as a means for improving the manufacturing yield of the liquid crystal display device, a protective film in the terminal portion is also separated between the video signal wirings. As a result, a short circuit between the video signal wirings at the terminal can be remedied.

It is desirable that the gate insulating film constituting the thin film transistor is formed of a laminated film made of a plurality of different materials. In this case, at least one layer of the gate insulating film is formed of a material different from the protective film. The protective film can be selectively etched while leaving at least one layer of the gate insulating film. Therefore, all the gate insulating films are not etched when the protective film is etched, and there is no concern that the scanning wiring is exposed.

It is desirable to use an alumina film as a laminated film constituting the gate insulating film. Generally, a protective film made of SiN or the like is processed by a dry etching method using a fluorine-based gas. The alumina film has excellent resistance to fluorine-based gas, and can be selectively etched with the protective film. Specific examples of the laminated film include an alumina film and a SiN structure from the scanning wiring side. In this structure, when the etching time of the protective film is increased in consideration of the process margin, the gate insulating film SIN is etched at the removed portion of the protective film, but the scanning wiring is covered with the alumina film and the exposed portion is exposed. There is nothing to do.

As an example of applying an alumina film to the laminated film constituting the gate insulating film, the scanning wiring may be made of A 1, an alloy containing A 1 as a main component, or A 1 or A self-oxidizing film of the scanning wiring is formed as a laminated wiring coated with an alloy containing A A as a main component. An alumina film can be easily formed by the anodic oxidation method, and an insulating film excellent in withstand voltage with few pinholes can be obtained. When the additional capacitance is provided, at least the protective film in the image display area has a structure separated from the video signal wiring, and the scanning wiring is A 1, or an alloy containing A 1 as a main component, or A1 or a laminated wiring covered with an alloy containing A1 as a main component, and an insulating film constituting the additional capacitance is an alumina film which is a self-oxidized film of the scanning wiring. This structure has two effects. One is that, similarly to the above operation, a defective pattern of a-Si or a video signal wiring can be removed, and a short circuit failure and a point defect failure between video signal wirings can be significantly reduced. Secondly, since the alumina film is hardly reduced during the processing of the protective film, the insulating film (alumina film), which forms the additional capacitance, is more likely to be side-etched than the upper electrode, which forms the additional capacitance. . Therefore, a substantially uniform additional capacitance can be formed over the entire image display area. As the upper electrode of the additional capacitance, a conductive film containing Cr or A 1 as a main component, or a laminated film in which the conductive film is disposed as an upper layer is preferable. The conductive film has excellent resistance to a fluorine-based gas. Therefore, by using a dry etching method using a fluorine-based gas for processing the protective film, the reduction in the film thickness of the upper electrode can be made very small, and an additional capacitance with very little variation can be formed over the entire image display area.

Further, by using the ITO extending from the pixel electrode to the upper electrode of the additional capacitance, the variation of the additional capacitance can be reduced. This is because I T0 is a conductive film having excellent chemical resistance, and can sufficiently secure an etching selectivity even in dry etching using a fluorine-based gas.

One of the causes of the point defect is that a-Si connected to the video signal wiring material or the video signal electrode remains on the pixel electrode due to poor patterning. There is. According to the present invention, at least a part of the end of the pixel electrode positioned substantially parallel to the video signal wiring is located in the opening of the protective film. With this structure, the defective pattern connected to the pixel electrode can be removed. This structure can be realized by performing the etching process of a-Si or the video signal wiring material again after processing the protective film. When an insulating film having a small etching selectivity with respect to a—S i is used for the protective film, the bad buttery of a—S i is removed in a self-aligned manner when the protective film is etched. The effect of relieving the above-described point defect increases as the length of the edge of the pixel electrode located at the opening of the protective film increases.

The protective film is desirably made of silicon nitride or silicon oxide. These films can be easily etched with a fluorine-based gas. Furthermore, since the fluorine-based gas also etches a-Si, the defective pattern of a-Si is also etched at the time of etching of the protective film, so that an additional process such as re-etching is not required. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plan view of a unit pixel according to the liquid crystal display device of the first embodiment of the present invention:

Figure 2 is a cross-sectional view of Ding F Ding unit according to the liquid crystal display device of the first embodiment of the present invention ₌

FIG. 3 is a sectional view of a video signal wiring portion according to the liquid crystal display device of the first embodiment of the present invention.

FIG. 4 is a cross-sectional view of the additional capacitance section according to the liquid crystal display device of the first embodiment of the present invention.

FIG. 5 is a plan view of a unit pixel according to a liquid crystal display device of a second embodiment of the present invention. FIG. 6 is a sectional view of an additional capacitance section according to the liquid crystal display device of the second embodiment of the present invention.

FIG. 7 is a sectional view of an additional capacitance section according to the liquid crystal display device of the second embodiment of the present invention.

FIG. 8 is a plan view of a unit pixel of a liquid crystal display device according to a third embodiment of the present invention.

FIG. 9 is a plan view of a unit pixel of a liquid crystal display device according to a fourth embodiment of the present invention.

FIG. 10 is a sectional view of a scanning wiring section according to a liquid crystal display device of a fourth embodiment of the present invention.

FIG. 11 is a sectional view of an additional capacitance section according to a liquid crystal display device of a fourth embodiment of the present invention.

FIG. 12 is a plan view of a unit pixel of a liquid crystal display device according to a fifth embodiment of the present invention.

FIG. 13 is a sectional view of the liquid crystal display device of the present invention.

FIG. 14 is an equivalent circuit diagram of the entire liquid crystal display device of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Example 1

FIG. 1 is a plan view of a unit pixel showing a first embodiment of the present invention. A scanning wiring 2 made of A 1 is formed on a glass substrate 1, and the surface thereof is covered with an alumina film 3. The alumina film 3 can be formed in a self-aligned manner by an anodic oxidation method after the formation of the scanning wiring 2. On the alumina film 3, a gate insulating film 5 made of a SiN film, an intrinsic amorphous silicon (a-Si) film 6, an n-type a-Si film, a video signal wiring 7, and a source electrode 8 Become TFT formed Have been. A pixel electrode 4 made of an indium-tin oxide film (IT 0) is formed on a glass substrate 1, and one end of the pixel electrode 4 is connected to a source electrode 8. The other end of the pixel electrode 4 extends over the scanning wiring of an adjacent pixel having an alumina film formed on the surface to form an additional capacitance.

FIG. 2 and FIG. 3 show the cross-sectional shapes of the section AA ′ and the section BB ′ in FIG. As shown in the figure, a protective film 9 made of Si is formed on the video signal wiring and the FT. Further, in this embodiment, the gate insulating film SIN5 and the a-Si film 6 have substantially the same planar shape. By making the plane shapes substantially the same, these films can be processed by one photo-etching step, and the manufacturing process can be shortened.

The feature of the present embodiment is that the protective film 9 has a structure separated between the video signal wirings 7, and the protective film 9 is removed on the pixel electrode 4 and the scanning wiring 2. It is.

Since the a-Si pattern is located at the intersection of the TFT section and the scanning wiring and the video signal wiring, the registration pattern defect at the time of the a-Si not- It often occurs on the above. However, by forming the protective film 9 into the structure shown in Fig. 1 and applying a dry etching method using SF to process the protective film, a pattern defect remains on the scanning wiring 2 when the protective film 9 is processed. A—S i is also automatically removed. In the present embodiment, SiN is used for the protective film 9, but the same effect can be obtained even when Si〇X. When a method in which a—S i is not etched is used for processing of the protective film 9, the etching process of a—S i is performed again after the processing of the protective film 9, so that the distance between the adjacent video signal wirings 7 is reduced. The connected a—S i can be removed.

Since the material of the video signal wiring 7 is arranged on the scanning wiring as the source 8 drain electrode of the TFT and the upper electrode of the additional capacitance, the patterning failure of the video signal wiring is the same as the patterning failure of a-Si described above. Similarly on scan wiring 2 Many occur. As shown in FIG. 1, this can also be removed by removing the protective film 9 on the scanning wiring 2 and etching the material of the video signal wiring 7 again after processing the protective film 9. At this time, if the scanning wiring and the video signal wiring 7 are exposed at the terminal portion, the terminal portion may disappear when the etching is performed again. However, a force of covering the scanning wiring or the video signal wiring 7 of the terminal portion with ITO constituting the pixel electrode 4 or a conductive film constituting the scanning wiring or the video signal wiring 7 is formed inside the protective film 9. The above problem can be solved by disposing the terminal with ITO connected to the conductive film. This is because ITO has excellent chemical resistance and can secure a sufficient etching ratio with respect to the protective film even in dry etching using a fluorine-based gas.

As described above, by applying the structure of the present invention, a short circuit defect and a point defect defect between video signal lines in a liquid crystal display device can be significantly reduced, and the production yield of the liquid crystal display device can be improved. .

In the present embodiment, an alumina film 3 was employed as a part of the gate insulating film. The alumina film has a sufficient resistance to dry etching using a fluorine-based gas, and can selectively etch only the protective film 9 formed on the alumina film 3. Generally, the etching is performed for a longer time than the end time in order to prevent the etching residue of the protective film 9 from being generated. Even under such conditions, the scanning wiring 2 is covered with the alumina film 3 and is not exposed. In this embodiment, the scanning wiring 2 is made of A 1, and the A 1 is anodized to form an alumina film 3. By using the anodic oxidation method, an alumina film having few defects such as pinholes and excellent in withstand voltage can be obtained. In addition, as the scanning wiring 2 material, in addition to the above-mentioned A 1, an alloy mainly containing A 1, or a multilayer wiring covered with the above-mentioned A 1 or an alloy mainly containing A 1, is used. The same effect as that of the A1 wiring can be obtained. Fig. 4 shows the cross-sectional structure of the additional capacitance section (C-C 'section in Fig. 1). In this embodiment, IT 0 extending from the pixel electrode 4 is used as the upper electrode of the additional capacitance. IT〇 is a conductive film having excellent chemical resistance, and the SiO 2 film 9 as a protective film on IT〇 can be selectively removed by dry etching using a fluorine-based gas. Therefore, the pattern of the IT〇 pattern is not changed due to the etching of the IT 時に pattern when the protective film 9 is processed, and the variation of the additional capacitance in the panel surface can be reduced.

In the present embodiment, the structure is such that the protective film in the image display area is separated between the video signal wirings. Further, as a means for improving the production yield of the liquid crystal display device, a protective film at the terminal portion is also separated between the video signal wirings. Can be remedied: Example 2

FIG. 5 is a plan view of a unit pixel showing a second embodiment of the present invention: A scanning wiring 2 made of A 1 is formed on a glass substrate 1, and the surface thereof is covered with an alumina film 3. . The alumina film 3 can be formed in a self-aligned manner by anodizing after patterning the scanning electrode 2. On the alumina film 3, a TFT composed of a gate insulating film 5 made of an S 1 X film, an a-Si film 6, an n-type a-Si film, a video signal wiring 7, and a source electrode 8 is formed. I have. On the glass substrate 1, a pixel electrode 4 made of an indium tin oxide film (I-cho) is formed, and one end thereof is connected to a source electrode 8. The other end of the pixel electrode 4 is connected to an upper electrode 20 for additional capacitance, and forms an additional capacitance with the scanning wiring 2 of an adjacent pixel having an alumina film 3 formed on the surface. The upper electrode 20 for additional capacity is composed of Cr. Further, a protective film 9 made of SiN is formed on the video signal wiring 7 and the TFT. In this embodiment, as in the first embodiment, the gate insulating film S i ヽ ′ film 5 and the a-S i film 6 have substantially the same planar shape, thereby simplifying the manufacturing process. FIG. 6 shows a cross-sectional shape of a portion D-D 'in FIG. The additional capacitance is formed from the glass substrate 1 side in the order of the scanning wiring 2 of A1, the alumina film 3, and the upper electrode 20 for additional capacitance composed of Cr.

The feature of this embodiment is that, in addition to the point that the protective film 9 is separated between the video signal lines 7 shown in the first embodiment, the additional electrode 20 for additional capacitance is composed of Cr. That is the point.

Cr has a very low etching rate in dry etching using a fluorine-based gas, so that the pattern of the upper electrode 20 for the additional capacitance does not disappear or shrink during processing of the protective film 9, and is formed within the substrate. An additional capacitance with less variation can be formed.

In this embodiment, Cr is used as the upper electrode 20 of the additional capacitor. However, a similar effect can be obtained with a conductive film containing Cr or A 1 as a main component.

Further, a similar effect can be obtained by using a laminated film in which the conductive film containing Cr or A 1 as a main component is disposed as an upper layer as the upper electrode 20 for the additional capacitance. FIG. 6 shows a specific example. The scan electrode 2 of A 1 is used as a lower electrode of the additional capacitor 2, the insulating film is composed of the alumina film 3 which is the anodic oxide film of the above A 1, and the upper electrode is an upper electrode for additional capacitor consisting of Ti from the alumina film side. The lower electrode 20 ′ and the upper electrode for additional capacitance 20 ′ composed of A 1. It is the surface of the laminated wiring that is exposed to the etching gas when processing the protective film 9. Since the surface layer is made of A〗, the upper electrodes 20 ′ and 20 ″ of the additional capacitance do not disappear when the protective film 9 is processed.

Example 3

FIG. 8 is a plan view of a unit pixel showing a third embodiment of the present invention. A scan wiring 2 'made of Cr is formed on a glass substrate 1, and a gate insulating film 5, a-Si film 6, an n-type a-Si film, an n-type a-Si film, A TFT composed of the signal wiring 7 and the source electrode 8 is formed. Glass substrate 1 A pixel electrode 4 made of an indium-tin oxide film (ITO) is formed on the upper side, and one end thereof is connected to a source electrode 8. The other end of the pixel electrode 4 is connected to the upper electrode 20 of the additional capacitance, and forms an additional capacitance with the scanning wiring 2 of the adjacent pixel. As shown in the figure, a protective film 9 made of Si is formed on the video signal wiring 7 and the TF 、, and the protective film 9 is separated from the video signal wiring 7. .

The present embodiment is characterized in that the gate insulating film 5 is made of S 1 X which is the same material as the protective film 9.

The structure of this embodiment is manufactured according to the following procedure. A film of Cr is formed on a glass substrate 1 to form a scanning wiring 2 'pattern. Subsequently, a SiO x film 5, an a-Si film 6, and an n-type a-Si are continuously formed by the Frosma CVD method, and the TFT portion and the a at the intersection of the scanning wiring 2 ′ and the video signal wiring 7 are formed. Si film 6, n-type a—Island Si film. Thereafter, Six on the pixel electrode 4 is dry-etched into a pattern shown by a dotted line in FIG. Then, a film of the video signal wiring 7 material is formed and processed into the video signal wiring 7 pattern. Finally, S IX is formed as a protective film 9 and processed into a pattern shown by a dotted line in (b) of FIG. At this time, comparing the film thicknesses of the SiN in the portions A and B in FIG. 8, the portion B is thicker by the thickness of the gate insulating film. Accordingly, the etching time of the protective film 9 is By setting the time between the etching end time of the portion S i. \ To the etching end time of the portion S i N, the S i N on the pixel electrode 4 is removed, and the scanning wiring 2 ′ is C) Even when the gate insulating film 5 is made of the same material as the protective film 9, the planar shape of the protective film 9 according to the present invention can be manufactured without any problem by the above manufacturing method.

As in the first embodiment, the structure of this embodiment can remove the defective pattern of a-Si and the defective pattern of the video signal wiring 7 remaining on the scanning wiring 2 ′. Short circuit failure between video signal wiring 7 and point defect failure can be remedied: Embodiment 4

FIG. 9 is a plan view of a unit pixel showing a fourth embodiment of the present invention. On a glass substrate 1, a scanning electrode 2〃 made of Ta is formed, and on its surface, a gate insulating film consisting of a Ta 0 X film 5 ′ and a Si X film 5 is formed from the scanning electrode 2〃 side. A TFT comprising an Si film 6, an n-type a-Si film, a video signal wiring 7, and a source electrode 8 is formed. A pixel electrode 4 made of an indium monotin oxide film (ITO) is formed on a glass substrate 1, and one end of the pixel electrode 4 is connected to a source electrode 8. The other end of the pixel electrode 4 is connected to Cr, which is the upper electrode 20 for the additional capacitance, and forms an additional capacitance between itself and the scanning electrode 2 of the adjacent pixel. A protection film 9 made of SiN is formed on the video signal wiring 7 and the TFT, and the protection film 9 is separated between the video signal wirings 7. The feature of the present embodiment is a structure in which the protective film 9 on the pixel electrode 4 and the scanning wiring 2 is partially removed, and the protective film 9 is separated between the video signal wirings 7 and the gate. The point is that the insulating film is composed of a laminated film of the SiN film 5ZTaOx film 5 '.

Since the protective film 9 is separated between the video signal wirings 7, short-circuit defects and point defects due to a-Si and poor patterning of the video signal wiring can be reduced as in the first embodiment.

FIG. 10 shows a cross-sectional shape of a portion EE ′ in FIG. The 3 1 ′ film 5 T a O x film 5 ′ is formed so as to cover at least the scanning wiring 2 before forming the protective film 9. Then, the SiN film 5 as the gate insulating film located at a portion where the SiN film 9 as the protective film is removed is removed when the SiM film 9 as the protective film is etched. However, the scanning wiring 2 ′ is covered with the Ta〇X film 5 ′, which is another insulating film constituting the gate insulating film, and is not exposed. FIG. 11 shows a cross-sectional shape of the additional capacitance section (section FF ′ in FIG. 10). As described above, the gate insulating film at the portion where the protective SiN film 9 is to be removed, the SiN film 5 which is the film to be removed is a force to be removed. 20 serves as a mask, and the SiOx film 5 as a gate insulating film remains. In this embodiment, the insulating film of the additional capacitance is formed by a laminated film of the Six film 5ZTa0x film 5 '.

As shown in FIGS. 10 and 11, the present structure has a structure in which the SIX film 5 as the gate insulating film remains only under the protective film and under the upper electrode of the additional capacitor.

In addition to the structure of the gate insulating film of the present embodiment, similar effects can be obtained by forming a laminated film composed of a plurality of different materials. This is because at least one layer of the gate insulating film is made of a material different from that of the protective film, so that the protective film can be selectively etched and the scanning wiring is not exposed.

Example 5

I 2 [2 is a plan view of a unit pixel showing a fifth embodiment of the present invention. Glass substrate: A scanning wiring 2 made of A 1 is formed thereon, and the surface thereof is covered with an alumina film 3. ing. The alumina film 3 can be formed in a self-aligned manner by anodizing after the patterning of the scanning wiring 2. On the alumina film 3, a TFT composed of a gate insulating film 5, composed of a Si— \ 'film, a—Si film 5, an n-type a—Si film, a video signal wiring 7, and a source electrode 8 is formed. ing. On the glass substrate 1, a pixel electrode 4 made of an indium tin oxide film (IT〇) is formed, and one end thereof is connected to a source electrode 8. The other end of the pixel electrode 4 extends to above the scanning wiring 2 of an adjacent pixel having the alumina film 3 formed on the surface, and forms an additional capacitance. A protection film 9 made of SIX is formed on the video signal wiring 7 and the TFT, and the protection film 9 is separated between the video signal wirings 7. 1 δ In the present embodiment, at least a part of the end of the pixel electrode 4 parallel to the video signal wiring 7 is located at the opening of the protective film 9 as shown in the part C in FIG. It is characterized by being located.

This embodiment has the following effects in addition to the effects shown in the first embodiment. One of the causes of the point defect is that a-Si connected to the video signal wiring material or the video signal wiring 7 on the pixel electrode 4 remains due to a pattern defect. According to the structure of this embodiment, the defective pattern of a—S i that connects the video signal line 7 and the pixel electrode 4 during the processing of the S i X film 9 serving as the protection film can be removed. By etching the video signal wiring material again after the processing, the defective pattern of the video signal wiring 7 connected to the pixel electrode 4 can be removed. This effect increases as the length of the edge of the pixel electrode 4 located at the opening of the protective film 9 increases.

Example 6

Hereinafter, examples of the liquid crystal display device of the present invention will be described.

FIG. 13 is a schematic sectional view of a liquid crystal display device showing the structure of this embodiment. On the lower glass substrate 1 with reference to the liquid crystal layer 200, the scanning wiring 2 and the video signal wiring 7 are formed in a matrix, and are made of ITO via the TFT formed near the intersection. Drive pixel electrode 4. On the opposing glass substrate 100 opposing across the liquid crystal layer 200, the opposing electrode 104 made of IT〇 and the color filter 102, the color filter protective film 103, the black matrix for shading A light-shielding film 101 for forming a pattern is formed. No.

13 The central part in Fig. 13 is a cross section of one pixel part, the left part is a cross section of the part where the external lead-out terminal is present at the left edge part of a pair of glass substrates, and the right part is a external part at the right side part of a pair of glass substrates. The cross section of a portion where no terminal is present is shown. The sealing material SL shown on the left and right sides of FIG. 13 is configured to seal the liquid crystal layer 2 ◦ 0, excluding the liquid crystal filling port (not shown) It is formed along the entire edge of the glass substrate 1, 100. The sealing material is made of, for example, epoxy resin. The counter electrode 104 on the side of the counter glass substrate 100 is connected at least at one position to an external lead wire formed on the glass substrate 1 by a silver paste material SIL. This external lead-out wiring is formed in the same manufacturing process as each of the scanning wiring 2, the source electrode 8, and the video signal wiring 7. Each layer of alignment film 0 RI 1, 0 RI 2, pixel electrode 4, protective film 9, color filter protective film 103, and gate insulating film SIN film 5 are inside the sealing material SL. The polarizing plates 105, 105 'are formed on the outer surfaces of a pair of glass substrates 1, 100, respectively. The liquid crystal layer 200 is sealed between a lower alignment film R i1 for setting the direction of liquid crystal molecules of the liquid crystal layer 200 and the upper alignment film 〇RI2, and is sealed with a sealing material SL. The lower alignment film RI 1 is formed on the protective film 9 on the glass substrate 1 side or on the pixel electrode 4. On the inner surface of the opposite glass substrate 100, a light-shielding film 101, a color filter 102, a color filter protective film 103, a counter electrode 104 and an upper alignment film 〇1¾1 2 are sequentially laminated to provided ₌ the liquid crystal display device to form a layer of the glass substrate 1 side and the opposing glass substrate 1) Y side separately and then superimposing the upper and lower glass substrates 1, 1 0 0, both It is assembled by enclosing liquid crystal 200 in between. By controlling the transmission of light from the backlight BL at the pixel electrodes 4, a D-drive type liquid crystal display device is constructed.

In this embodiment, ₌ the TFT substrate employing the TF T substrate illustrated in FIG. 1 has the following structure. A scanning wiring 2 made of A 1 is formed on a glass substrate 1, and the surface thereof is covered with an alumina film 3. The alumina film 3 can be formed in a self-aligned manner by anodic oxidation after patterning the scanning wiring 2. On the alumina film 3, a gate insulating film δ consisting of a SiN film, a-Si film 6, an n-type a-Si film, a video signal wiring 7, and a TFT consisting of a source electrode 8 Is formed. Indium-tin monoxide film on glass substrate 1

A pixel electrode 4 made of (IT 0) is formed, and one end of the pixel electrode 4 is connected to the source electrode 8. The other end of the pixel electrode 4 extends to the scanning wiring 2 of an adjacent pixel having an alumina film formed on the surface to form an additional capacitance: a protective film made of Si on the video signal wiring 7 and the TFT. 9 are formed and are separated between the video signal wirings 7 in the image display area. In addition to the TF board having the above structure, the TF-cables shown in FIG. 5, FIG. 8, FIG. 9, FIG. Fig. 14 shows the equivalent circuit of the whole display device. X: G is the video signal wiring connected to the pixel on which the green filter G is formed. Similarly, X: B is X _; R are the video signal lines connected to the pixels where the red filter R is formed.走査, Υ ₂ ,... Are scanning wirings for selecting each pixel column. These scanning wirings are connected to the vertical scanning circuit V. The video signal wiring is connected to the video signal activation circuit Η. S-J converts the information for the cathode ray tube from the power supply circuit and the host (upper processing unit) to obtain multiple divided and stabilized voltage sources from one voltage source to the information for the liquid crystal panel. It is a circuit including a circuit.

The liquid crystal display device configured as described above can significantly reduce short circuit defects and point defect defects between video signal wirings, and can manufacture liquid crystal display devices with high yield.

As described above, according to the present invention, short-circuit defects and point defect defects between video signal wirings caused by patterning defects of a-Si films and video signal wirings can be significantly reduced. Therefore, a liquid crystal display device can be manufactured with a high yield. Industrial applicability As described above, the liquid crystal display device according to the present invention reduces short circuit defects and point defect defects between video signal lines, and is useful for improving the production yield.

Claims

1. A plurality of scanning wirings, a plurality of video signal wirings intersecting them in a matrix, a plurality of thin film transistors formed corresponding to intersections of these wirings, and a plurality of An active matrix substrate having a plurality of pixel electrodes connected thereto, and a counter substrate provided to face the active matrix substrate and having a counter electrode facing each of the pixel electrodes;

A liquid crystal layer sealed between the active matrix substrate and the opposing substrate,

On the active matrix substrate, a protective film for protecting the plurality of video signal lines and the plurality of thin film transistors separated on the scanning wiring region between the adjacent signal lines is formed. Characteristic liquid crystal display device.

2. The method according to claim 1, wherein each of the plurality of pixel electrodes is formed in a region surrounded by the scanning wiring and the video wiring, and the protective film is separated on the pixel electrodes. Liquid crystal display device.

3. The liquid crystal display device according to claim 1, wherein the scanning wiring is covered with an insulating film.

4. The liquid crystal display device according to claim 3, wherein the insulating film is exposed to the liquid crystal layer on the scanning wiring region between the signal wirings from which the protective film is separated.

5. The liquid crystal display device according to claim 4, wherein the scanning wiring is made of a metal containing A 1 as a main component, and the insulating film is made of alumina.

6. The liquid crystal display device according to claim 5, wherein the scanning wiring has a laminated structure of A 1 and an alloy having A 1 as a main component.

7. The liquid crystal display device according to claim 4, wherein the scanning wiring is made of metal containing Ta as a main component, and the insulating film is made of TaOx.

8. The liquid crystal display device according to claim 1, wherein the scanning wiring forms a gate electrode of the thin film transistor, and a stacked gate insulating film is formed on the gate electrode. .

9. The liquid crystal display device according to claim 8, wherein the gate insulating film includes an alumina film and a Si film.

10. The claim 8, wherein the gate insulating film is a 〇 X film, and

A liquid crystal display device comprising a SiX film.

11. The claim 3, wherein one end of the pixel electrode extends over the scanning wiring region where the protective film is separated, and the extended portion and the scanning wiring formed below the portion are connected to each other. A liquid crystal display device characterized in that an additional capacitance is formed by an insulating layer covered by the scanning wiring.

12. The additional capacitance upper electrode according to claim 3, further comprising an additional capacitance upper electrode connected to one end of the pixel electrode and formed on the scanning wiring region in which a protective film is separated. A liquid crystal display device, wherein an additional capacitance is formed by a scanning wiring formed below the portion and an insulating layer covered by the scanning wiring.

13. The liquid crystal display device according to claim 12, wherein the additional electrode for an additional capacitor is composed of Cr.

14. The liquid crystal display device according to claim 12, wherein the upper electrode for additional capacitance is stacked.

15. The liquid crystal display device according to claim 14, wherein the laminated upper electrode for additional capacitance contains Cr and A 1.