KR100885839B1 - Liquid crystal display - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device capable of repairing a gate line disconnection and a repair method thereof in a storage-on-gate liquid crystal display device, wherein the repair structure of the liquid crystal display device is vertically and horizontally arranged in a pixel region. A substrate having a gate line and a data line having a disconnection region, a thin film transistor formed near an intersection point of the gate line and the data line, and connected to the data line, and a gate line and a gate insulating layer including the disconnection region. A passivation layer formed on the entire substrate via the thin film transistor and the storage electrode, and a storage region overlapped between the passivation layer and a pixel region formed on the passivation layer and partitioned by the gate line and the data line. A pixel electrode overlapping a portion of the gate, and the gate And a disconnection connection structure interconnecting the storage electrode overlapped with the line and the disconnected gate line.

Description

Liquid crystal display device {LIQUID CRYSTAL DISPLAY}

1 is an exemplary view showing a conventional storage on common liquid crystal display device.

Figure 2 is an exemplary view showing a conventional storage on-gate liquid crystal display device.

3 is an exemplary view showing a cross-sectional configuration of the storage capacitor cut along the line A-A 'in FIG.

4 is an exemplary view showing a storage on gate liquid crystal display device according to an exemplary embodiment of the present invention.

5 is an exemplary view showing a cross-sectional configuration cut along the line B-B 'in FIG.

6A to 6E are exemplary views sequentially showing a process sequence of a liquid crystal display device according to an exemplary embodiment of the present invention.

7 is an exemplary view illustrating a repair method of a liquid crystal display device according to an exemplary embodiment of the present invention.

8 is an exemplary view showing a cross-sectional configuration cut along the line D-D 'in FIG.

*** Explanation of symbols for main parts of drawing ***

2: gate line 2a: gate electrode

4: data line 4a: source electrode

4b: drain electrode 5: active layer                 

7: pixel electrode 8a: first contact hole

8b: second contact hole 11, 16: storage electrode

13: gate insulating film 15: protective film

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device capable of repairing a gate line disconnection defect generated during a thin film transistor array process, and a manufacturing method thereof.

Liquid crystal displays (LCDs) used in display devices such as televisions and graphic displays have been developed in place of the CRT (Cathode Ray Tube). In particular, TFT-LCDs equipped with thin film transistors (TFTs) for each pixel arranged in a matrix form have high-speed response characteristics and suitable for high pixel numbers, so that the picture quality, size, and color of a screen comparable to those of CRTs are high. Etc. are realized.

In general, a TFT-LCD consists of a lower substrate in which TFTs and pixel electrodes are formed in each pixel arranged in a matrix form, an upper substrate in which color filters and a common electrode are formed, and a liquid crystal filled between the lower substrate and the upper substrate. In a TFT-LCD having a liquid crystal, a liquid crystal is driven in accordance with a voltage applied to a pixel electrode and a common electrode to display a predetermined image.

On the other hand, in order to increase the display screen quality in the TFT-LCD, it is necessary to keep the voltage of the first signal applied through the data line constant until the second signal is transmitted. The storage capacitor Cst is formed in each pixel.

Here, the storage capacitor is formed by a storage on common method of forming a capacitor by extending a predetermined portion of the gate line, and a storage on gate that forms a capacitor by arranging a storage line independent of the gate line. There is a (Storage On Gate) method.

Hereinafter, a storage on common and a storage on gate method for forming a storage capacitor will be described.

1 is a plan view illustrating a lower substrate of a conventional TFT-LCD for explaining a storage capacitor forming method of a storage on common method.

As illustrated, gate lines 2 are arranged on the glass substrate 1, and storage electrode lines 6 are independently formed between adjacent gate lines 2. 2) and the storage electrode line 6 are covered by a gate insulating film (not shown).

In addition, a data line 4 is formed on the gate insulating layer so as to be perpendicular to the gate line 2 and the storage electrode line 6, and a thin film transistor is formed near the intersection point of the gate line 2 and the data line 4. 10) is arranged.

The thin film transistor 10 includes a gate electrode 2a, source / drain electrodes 4a and 4b, and a semiconductor layer 5a, and the drain 4b passes through the first contact hole 8a to the pixel electrode. It is electrically connected with (7).

In addition, a pixel electrode 7 is formed in the pixel region, and thus a storage capacitor Cst is formed between the storage electrodes 11 formed to overlap a portion of the storage electrode line 6 disposed in the pixel region. In this case, the storage electrode line 6 is electrically connected to the pixel electrode through the second contact hole 8b.

FIG. 2 is a plan view illustrating a lower substrate of a conventional TFT-LCD for explaining a method of forming a storage on-gate storage capacitor. The gate lines 2 and the data lines 4 are formed on the glass substrate 1. Arranged so as to be orthogonal, a storage electrode 11 overlapping a predetermined portion of the gate line 2 is formed. In this case, the storage electrode 11 is disposed overlapping the gate line 2.

Although not shown, a gate insulating film is interposed between the gate line 2 and the data line 4 for the purpose of electrical insulation therebetween.

Near the intersection of the gate line 2 and the data line 4, a TFT 10 is formed to independently control the driving of each pixel, where the TFT 10 is a gate electrode which is a part of the gate line 2. (2a) and a gate insulating film (not shown) covering the gate electrode 2a, a semiconductor layer 5a formed in the form of a pattern on the gate insulating film, and a predetermined interval spaced on the semiconductor layer 5a Disposed source / drain electrodes 4a, 4b. The drain electrode 4b is electrically connected to the pixel electrode 7 through the first contact hole 8a.

In addition, a pixel electrode 7 made of a transparent metal such as indium tin oxide (ITO) is disposed in the pixel region, and the gate line 2 and the data line 4 are formed as shown through the gate insulating film. The storage electrode, which is made together during the process, forms a storage capacitor Cst with a gate insulating layer interposed therebetween. The storage electrode 11 is electrically connected to the pixel electrode 7 through the second contact hole 8b.

3 is a cross-sectional view of the storage capacitor cut along the line A-A 'in FIG.

Referring to the cross section of the storage capacitor cut along the line AA ′ of FIG. 3, the gate line 2 and the gate line 2 formed on the substrate 1 to apply a gate signal to the gate electrode of the thin film transistor are shown. A gate insulating film 13 formed on the entire surface of the substrate, the storage electrode 11 formed together during the source / drain formation process of the thin film transistor on the gate insulating film, and a protective film formed on the entire surface of the substrate on which the storage electrode 11 is formed. 15 and the pixel electrode 7 formed on the passivation layer 15, and the storage electrode 11 is connected to the pixel electrode 7 through the second contact hole 8b formed on the passivation layer 15. Electrically connected.

In this case, a storage capacitor Cst is formed between the gate line 2 and the storage electrode 11 with the gate insulating layer 13 therebetween.

However, various defects occur due to various causes such as dust of a film forming process, dust of a resist coating process, uneven drying of a cleaning process, and minute scratches on a glass substrate during manufacturing of a liquid crystal display device.

The defects may be classified into point defects and line defects or marking stains according to the type of defects. Point defects are caused by defects such as thin film transistors or pixel electrodes, and predecessors are disconnections between lines. (open), short (short) and breakdown of the thin film transistors by static electricity.

These defects are becoming more important as the display area of the image device becomes larger, and a redundancy and repairable design has been introduced as a way to proactively cope with such defects. .

However, in the storage on gate type liquid crystal display device illustrated in FIGS. 2 and 3, there is a problem in that the repair is impossible when the gate line is disconnected in the storage capacitor Cst formation region.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to provide a liquid crystal display device that can be repaired even when a defect occurs in disconnection of a gate line.

Other objects and features of the present invention will be described in detail in the configuration and claims of the following invention.

In order to achieve the object of the present invention as described above, a repair structure of a liquid crystal display device includes a substrate having a gate line and a data line arranged vertically and horizontally to define a pixel region, and having a disconnection region; A storage electrode formed near an intersection point and overlapping the thin film transistor connected to the data line and the gate line including the disconnection region and the gate insulating film, and a protective film formed on the entire substrate via the thin film transistor and the storage electrode; A pixel electrode formed on the passivation layer and disposed in a pixel region defined by the gate line and the data line and overlapping a portion of the gate line; and a storage electrode overlapping the gate line and the disconnected gate line. It includes a single wire connection structure for connecting.
The repair structure of the liquid crystal display device includes a plurality of gate lines and data lines arranged vertically and horizontally; A thin film transistor formed near an intersection point of the gate line and the data line and connected to the data line; A pixel electrode disposed in the pixel region partitioned by the gate line and the data line; And a disconnection connection structure connecting the storage electrode overlapped with the gate line and the disconnected gate line through welding when a disconnection occurs in a gate line in a liquid crystal display device having a portion of the storage electrode protruding into the pixel region. .
The storage electrode in which the portion protrudes into the pixel area may be formed in a '┓' shape.

Hereinafter, a liquid crystal display according to the present invention having the above characteristics will be described in detail with reference to the accompanying drawings.

4 is a view illustrating a repairable storage on gate liquid crystal display device according to an exemplary embodiment of the present invention.

As shown in the figure, in the liquid crystal display device of the present invention, the gate line 2 and the data line 4 are vertically and horizontally arranged on the glass substrate 1, and the gate line 2 and the data line 4 are arranged. And a storage electrode 16 in which a portion of the pixel overlaps the gate line 2 and protrudes into the pixel region. The storage electrode may be formed in a '-' shape.

Although not shown, a gate insulating film is interposed between the gate line 2 and the data line 4 for the purpose of electrical insulation therebetween, and the thickness thereof is about 4000 kPa. In addition, a thin film transistor 10 for independently controlling driving of each pixel is formed near the intersection point of the gate line 2 and the data line 4, where the thin film transistor 10 is a gate line 2. A gate electrode 2a which is a part of the gate electrode, a gate insulating film (not shown) covering the gate electrode 2a, a semiconductor layer 5a formed in a pattern shape on the gate insulating film, and on the semiconductor layer 5a. And source / drain electrodes 4a and 4b disposed at predetermined intervals. The drain electrode 4b is electrically connected to the pixel electrode 7 through the first contact hole 8a.                     

In the pixel region, a pixel electrode 7 made of a transparent metal such as indium tin oxide (ITO) is interposed between the storage electrode 16 overlapping the gate line 2 and a protective film (not shown) formed on the entire surface of the substrate. The storage capacitors 16 are disposed to overlap each other, and the storage electrode 16 formed at the time of forming the gate line 2 and the data line 4 is formed with the gate insulating film interposed therebetween. The storage electrode 16 is electrically connected to the pixel electrode 7 through the second contact hole 8b.

The second contact hole 8b is formed in a portion protruding to the pixel area of the storage electrode 16.

Hereinafter, the structure of the storage capacitor Cst of the present invention will be described in detail with reference to a cross-sectional view taken along the line BB ′ of FIG. 4.

FIG. 5 is a cross-sectional view taken along the line BB ′ of FIG. 4.

As shown in the drawing, the thin film transistor 10 is formed on the substrate 1 and has a gate electrode 2a to which a scan signal is applied, and an active layer provided to transmit a data signal in response to the scan signal. 5, the gate insulating layer 13 and the active layer 5 which electrically isolate the active layer 5 and the gate electrode 2a. A source electrode 4a formed at an upper side to apply a data signal, a drain electrode 4b for applying a data signal to the pixel electrode 7, and a source electrode 4a and a drain electrode 4b for protecting the source electrode 4a The formed protective film 15 and the pixel electrode 7 on the protective film electrically connected to the drain electrode 4b through the first contact hole 8a.

The active layer 5 is a semiconductor layer 5a formed by depositing amorphous silicon (a-Si) and n + doped with impurities such as phosphorus (P) on top of both sides of the semiconductor layer 5a. It consists of an ohmic contact layer 5b formed by depositing amorphous silicon.

When a scan signal having a high level is applied to the gate electrode 2a, a channel through which electrons can move is formed in the active layer 5, so that the data signal of the source electrode 4a is an active layer. It transfers to the drain electrode 4b via (5). On the other hand, when a scan signal having a low level is applied to the gate electrode 2a, the channel formed in the active layer 5 is blocked, so that the transmission of the data signal to the drain electrode 4b is stopped.

In addition, the passivation layer 15 protects the source electrode 4a and the drain electrode 4b, and serves to electrically isolate the pixel electrode 7 and the source electrode 4a.

 The storage capacitor Cst is formed on the substrate 1 to apply a gate signal to the gate electrode 2a of the thin film transistor 10, and to the entire surface of the substrate on which the gate line 2 is formed. The gate insulating layer 13 formed, the storage electrode 16 formed together during the source / drain formation process of the thin film transistor 10 on the gate insulating layer 13, and the passivation layer formed on the entire surface of the substrate on which the storage electrode 16 is formed. And a pixel electrode 7 formed on the passivation layer 15, and the storage electrode 16 is formed on the passivation layer 15 of the portion protruding into the pixel region. It is electrically connected to the pixel electrode 7 through.

The storage capacitor Cst is formed in a region where the gate line 2 and the storage electrode 16 overlap with the gate insulating layer 13 formed on the front surface of the substrate. At this time, the thickness of the gate insulating film 13 is about 4000 kPa, and the thickness of the protective film formed between the pixel electrode 7 and the storage electrode 16 is about 2000 kPa.
In the liquid crystal display device manufactured through the above process, disconnection of the gate line may occur in the region where the storage capacitor Cst is formed due to various causes, and when the disconnection failure occurs, the liquid crystal display device is repaired. Should be.
Hereinafter, a method of making the repairable liquid crystal display device, a method of repairing when a disconnection defect occurs in the liquid crystal display device, and a repair structure of the liquid crystal display device repairing the disconnection failure will be described.

First, a manufacturing method for repairing a liquid crystal display element will be described.

6A to 6E are exemplary views sequentially showing a process sequence of a liquid crystal display device according to an exemplary embodiment of the present invention.

First, as shown in FIG. 6A, a metal material is sputtered and deposited on the lower substrate 1, and then patterned by photo-etching using a photoresist to form a thin film. A gate line (not shown) for applying the gate electrode 2a of the transistor and the gate signal of the gate electrode 2a is formed.

Next, as shown in FIG. 6B, an insulating material is entirely deposited on the lower substrate 1 on which the gate electrode 2a and the gate line are formed to form a gate insulating film 13. As the material of the gate insulating film 13, an inorganic material such as SiNx or SiOx is used, and the thickness thereof is about 4000 kPa. On the gate insulating layer 13, a semiconductor layer 5a made of amorphous silicon (Si) and an ohmic contact layer 5b made of n + amorphous silicon doped with phosphorus (p) are successively deposited, and then patterned to form a thin film transistor. The active layer 5 is formed.

As illustrated in FIG. 6C, a metal material is entirely deposited on the ohmic contact layer 5b and the gate insulating layer 13 and then patterned. The patterned metal material layer may include a storage electrode 16 that forms a gate line and a storage capacitor Cst between the source / drain electrodes 4a and 4b of the thin film transistor and a data line (not shown) and a gate insulating layer 13 therebetween. )

The storage electrode 16 overlaps a portion of the gate line, and a portion of the storage electrode 16 protrudes into the pixel region as illustrated in FIG. 4, and the shape of the storage electrode 16 may be various.

Thereafter, the ohmic contact layer 5b exposed on the source electrode 4a and the drain electrode 4b is removed by an etching operation.

6D, a passivation layer 15 is entirely formed on the gate insulating layer 13 including the exposed semiconductor layer 5a and the source and drain electrodes 4a and 4b. do. Then, the portion of the protective film 15 on the drain electrode 4b of the thin film transistor and the portion of the protective film on the stepped portion of the storage electrode 11 are removed by an etching operation using a mask pattern to expose a portion of the drain electrode 4b. The first contact hole 8a and the second contact hole 8b exposing a portion of the storage electrode 16 are formed.

As the material of the protective film 15, an inorganic material such as SiNx or SiOx is used, and the thickness thereof is about 4000 kPa. For high aperture pixel structures, organic materials such as benzocyclobutene (Benzocyclobutene), spin on glass (SOG), and photo-acryl (SOG) having a low dielectric constant are used to have a thickness of about 2 to 3 μm.

Subsequently, as illustrated in FIG. 6E, an ITO material is deposited on the protective film 15 by sputtering, and then patterned to form the pixel electrode 7. The pixel electrode 7 is connected to the drain electrode 4b of the thin film transistor through the first contact hole 8a and is connected to the storage electrode 16 through the second contact hole 8b.

Through the above process, a repairable liquid crystal display device can be manufactured, and due to various causes such as dust during the film formation process, dust during the resist coating process, uneven drying of the cleaning process, and minute scratches on the glass substrate. Therefore, when disconnection failure of the gate line occurs in the region where the storage capacitor Cst is formed, the lower end portion of the storage electrode 16 protruding into the pixel region is cut, and then left and right sides of the portion where the gate line is disconnected using a laser. By welding, the gate line disconnection can be repaired.

Hereinafter, a repair method and a repair structure of a liquid crystal display device according to the present invention will be described in detail with reference to FIG. 7.

As shown in the drawing, the gate lines 2 and the data lines 4 are arranged on the glass substrate 1 so as to be perpendicular to each other, and formed at the intersection of the gate line 2 and the data line 4. A pixel formed in the pixel region by overlapping the thin film transistor 10 and a portion of the gate line 2, and having a portion protruding in the pixel region defined by the gate line 2 and the data line 4. In the storage-on-gate type liquid crystal display device electrically connected through the electrode 7 and the second contact hole 8b, the disconnection of the gate line is poor in the region where the gate line 2 and the storage electrode 16 overlap each other. If this occurs, first, in order to repair this, the storage electrode having an equipotential with the pixel electrode 7, becomes a component of the storage capacitor Cst, protrudes into the pixel area, and the second contact hole 8b is located ( 16) Cut along line C-C '. Next, in order to electrically connect the disconnected portion of the gate line, the left and right sides of the storage electrode 16 overlapping the gate line 2 are welded by using a laser.

As described above, the storage capacitor Cst ′ formed after the repair includes a storage electrode 16 and a pixel electrode 7 overlapping a portion of the storage electrode 16 with a passivation layer (not shown) therebetween.

FIG. 8 is an exemplary view illustrating a cross-sectional structure taken along the line D-D ′ of FIG. 7 and illustrates the storage capacitor Cst ′ formed after repairing a gate line disconnection failure.

As shown in the figure, when there is no disconnection of the gate line, the storage capacitor Cst is formed by the gate insulating film 13 formed to be about 4000 Å thick between the gate line 2 and the storage electrode 16, and the gate line The storage capacitor Cst 'formed after the repair of the disconnection has a source / drain due to laser welding for reconnecting the disconnected gate line and the disconnected gate line of the second contact hole 8b connected to the pixel electrode with respect to the storage electrode. The storage electrode 16 made of the same material as the electrode and the pixel electrode 7 made of the ITO material are formed by the passivation layer 15 having a thickness of about 2000 Å.
Therefore, the repair structure of the liquid crystal display device when the disconnection failure occurs in a part of the gate line of the liquid crystal display device is a disconnection line connecting the storage electrode overlapped with the gate line and the disconnected gate line as shown in the figure. It includes a connection structure. In this case, a portion of the storage electrode is cut and electrically separated from the pixel electrode.

After the repair, the storage electrode and the pixel electrode form the storage capacitor Cst ', and the area of the metal materials forming the storage capacitor Cst' is reduced, but the thickness of the insulating film formed between the metal materials is reduced. The same value of the storage capacitor Cst as before the repair can be maintained.

As described above, the present invention is a storage on-gate type liquid crystal display device structure formed by a gate insulating film formed between a storage electrode consisting of a gate line and a source / drain electrode, a portion of the storage electrode overlaps the gate line and the rest By forming a portion protruding into the pixel region, repair of a gate line disconnection defect that is fatal to a liquid crystal display device product can be repaired, thereby improving the yield of the product.

Claims (10)

A substrate having a gate line and a data line arranged vertically and horizontally to define a pixel area and having a disconnection area formed thereon; A storage electrode formed near an intersection point of the gate line and the data line and overlapping the thin film transistor connected to the data line, the gate line including the disconnection region, and a gate insulating layer interposed therebetween and partially protruding into the pixel region; A protective film formed on the entire substrate via the thin film transistor and the storage electrode; A pixel electrode formed on the passivation layer and disposed in a pixel region partitioned by the gate line and the data line and overlapping a portion of the gate line and electrically separated from the storage electrode; A disconnection connection structure interconnecting and repairing both sides of the storage electrode overlapping the gate line and the disconnected gate line; And A storage capacitor formed between the storage electrode electrically separated from the pixel electrode and the pixel electrode; Repair structure of the liquid crystal display device comprising a. delete delete delete delete Providing a substrate having a gate line and a data line arranged vertically and horizontally to define a pixel region and having a disconnection region formed thereon; Forming a storage electrode along with a thin film transistor connected to the data line near an intersection point of the gate line and the data line, the storage electrode partially overlapping the gate line including the disconnection region and the remaining portion protruding into the pixel region; Forming a protective film on the entire substrate; Forming a pixel electrode disposed in the pixel area on the passivation layer and overlapping a portion of the gate line, and connecting the pixel electrode to the storage electrode; Cutting a portion of the storage electrode protruding into the pixel area to electrically separate the pixel electrode; And A welding process is performed to electrically connect both sides of the storage electrode overlapping the gate line and the disconnected gate line to each other to repair the gate line, and between the storage electrode and the pixel electrode electrically separated from the pixel electrode. Forming a storage capacitor; Repair method of a liquid crystal display device comprising a. delete delete The repair structure of claim 1, wherein the passivation layer has a thickness thinner than that of the gate insulating layer. delete

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