KR100690000B1 - Liquid Crystal Display Device And Method for Fabricating the same - Google Patents

Abstract

The present invention relates to a liquid crystal display device capable of preventing disconnection of a data line due to a step difference in a gate line, and a method of manufacturing the same.

The liquid crystal display device of the present invention includes a transparent substrate having a groove portion in which signal wiring is to be formed, a first metal pattern formed in the groove portion of the transparent substrate and forming a data line, a gate line, and a gate electrode of a thin film transistor, and overlapping the data line. A second metal pattern including source and drain electrodes of the formed thin film transistor, a gate insulating layer positioned between the first metal pattern and the second metal pattern, an active layer formed on the surface of the gate insulating layer and in contact with the source and drain electrodes; And a passivation layer for protecting the thin film transistor, a pixel electrode electrically contacting the drain electrode through a first contact hole formed in the passivation layer, and a surface of the passivation layer and formed through the second contact hole. A link electrode for electrically connecting the electrode is provided.

According to the present invention, the data line and the gate line are formed in the trench formed on the transparent substrate without the step, thereby preventing the disconnection of the data line due to the conventional gate line step.

Description

Liquid crystal display device and its manufacturing method {Liquid Crystal Display Device And Method for Fabricating the same}             

1 is a plan view of a conventional liquid crystal display device.

FIG. 2 is a cross-sectional view of the thin film transistor unit illustrated in FIG. 1 taken along a line A-A '.

3 is a cross-sectional view of the intersection of the gate line and the data line shown in FIG. 1 taken along the line BB ′;

4A through 4E are cross-sectional views illustrating a first mask process in a method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention.

5 is a plan view of a gate line and a data line formed by the first mask process;

6 is a cross-sectional view showing a second mask process in a method of manufacturing a liquid crystal display device according to an embodiment of the present invention.

7 is a plan view of a lower plate on which the second mask process is performed.

8 is a cross-sectional view showing a third mask process in a method of manufacturing a liquid crystal display device according to an embodiment of the present invention.

9 is a plan view of a lower plate on which the third mask process is performed.

10 is a cross-sectional view showing a fourth mask process in a method of manufacturing a liquid crystal display device according to an embodiment of the present invention.

11 is a plan view of a lower plate on which the fourth mask process is performed;

FIG. 12 is a cross-sectional view illustrating a contact portion between a data line and a source electrode illustrated in FIG. 11.

<Description of Symbols for Main Parts of Drawings>

2, 44: gate line 4, 42: data line

6, 40 gate electrode 8, 52 source electrode

10, 54: drain electrode 12: thin film transistor

11, 13, 62, 64, 66: contact hole 14, 68: pixel electrode

15, 56: storage electrode 16, 32: transparent substrate

18, 46: gate insulating film 20, 48: active layer

22, 50: ohmic contact layer 24, 60: protective film

30: storage capacitor 34: photoresist pattern

36: trench 38: metal seed layer

70: link electrode

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 preventing disconnection of a data line due to a step difference in a gate line, and a manufacturing method thereof.

In general, a liquid crystal display (LCD) device displays an image by adjusting light transmittance of liquid crystal cells according to a video signal. Among the liquid crystal display devices, an active matrix type in which switching elements are provided for each liquid crystal cell is suitable for displaying a moving image. In an active matrix liquid crystal display device, a thin film transistor (TFT) is mainly used as a switching element.

Referring to FIG. 1, a plan view of a conventional liquid crystal display device is shown. The liquid crystal display shown in FIG. 1 includes a thin film transistor 12 positioned at an intersection of the data line 2 and the gate line 4, and a pixel electrode connected to the drain electrode 10 of the thin film transistor 6. 6). The thin film transistor 12 is connected to the pixel electrode 14 through the gate electrode 6 protruding from the gate line 4, the source electrode 8 protruding from the data line 2, and the drain contact hole 11. Consisting of a drain electrode 10. In addition, the thin film transistor 12 further includes an active layer (not shown) for forming a conductive channel between the source electrode 8 and the drain electrode 10 by the gate voltage supplied to the gate electrode 12. The thin film transistor 12 selectively supplies the data signal from the data line 4 to the pixel electrode 14 in response to the gate signal from the gate line 2. The pixel electrode 14 is positioned in a cell region divided by the data line 4 and the gate line 2 and is made of indium tin oxide (ITO) material having high light transmittance. The pixel electrode 14 generates a potential difference from a common transparent electrode (not shown) formed on the upper substrate by a data signal supplied from the drain electrode 10. Due to this potential difference, the liquid crystal positioned between the thin film transistor substrate and the upper substrate is rotated by dielectric anisotropy and transmits light supplied from the light source via the pixel electrode 14 toward the upper glass substrate. The storage capacitor 30 formed between the pixel electrode 14 and the gate line 2 of the previous stage charges a voltage in a period where a gate high voltage is applied to the gate line 2 of the previous stage, and the pixel electrode 14 The voltage charged in the period during which the data signal is supplied is discharged to prevent the voltage variation of the pixel electrode 14. The storage capacitor 30 is provided by a storage electrode 15 electrically connected to the pixel electrode 14 through a contact hole 13 formed in the passivation layer, and a gate line 2 having a gate insulating layer interposed therebetween.

FIG. 2 is a cross-sectional view of the thin film transistor unit illustrated in FIG. 1 taken along the line A-A ', and FIG. 3 is a cross-sectional view of the intersection of the data line 2 and the gate line 4 illustrated in FIG. The cross section cut along the line B 'is shown. Referring to FIGS. 2 and 3, the method of manufacturing the liquid crystal display shown in FIG. 1 forms a gate line 2 and a gate electrode 6 by depositing and patterning a metal material on the transparent substrate 16. do. After the gate insulating film 18 is formed on the transparent substrate 16 on which the gate line 2 and the gate electrode 6 are formed, an amorphous silicon layer and an amorphous silicon layer doped with impurities are sequentially formed and then patterned. The active layer 20 and the ohmic contact layer 22 are formed. Next, the data line 4, the source and drain electrodes 8 and 10, and the storage electrode 15 are formed by depositing and patterning a metal material. Subsequently, the ohmic contact layer 22 exposed between the source electrode 8 and the drain electrode 10 is etched to expose the active layer 20. Then, the insulating material is deposited on the entire surface to form a protective film 24, and then patterned to form a contact hole. Next, the transparent electrode material is deposited on the entire surface and then patterned to form the pixel electrode 14.

In the liquid crystal display, the gate line 2 and the data line 4 use a low resistance material for good signal transmission as the panel becomes larger, and the thickness of the wiring becomes thicker. However, as the thickness of the gate line 2 becomes thicker, the step coverage of the gate insulating film 18 formed thereon becomes worse as the step becomes larger. When the step coverage of the gate insulating film 18 is deteriorated, as shown in FIG. 3, the data line 4 formed on the gate insulating film 18 at the intersection of the gate line 2 and the data line 4 is a stepped portion. The problem of disconnection will occur. As a result, the larger the size of the liquid crystal panel, the higher the defective rate is due to disconnection of the data line due to the gate step.

Accordingly, an object of the present invention is to provide a liquid crystal display device and a method of manufacturing the same, which can prevent disconnection of a data line due to a gate step.

Another object of the present invention is to provide a liquid crystal display device suitable for large size and a manufacturing method thereof.

In order to achieve the above objects, a liquid crystal display device according to the present invention includes a transparent substrate having a groove portion in which signal wiring is formed, a first metal formed in a groove portion of the transparent substrate and forming a data electrode, a gate line, and a gate electrode of a thin film transistor. A second metal pattern including a pattern, a source and a drain electrode of the thin film transistor formed to overlap the data line, a gate insulating layer positioned between the first metal pattern and the second metal pattern, and formed on the surface of the gate insulating layer. And an active layer in contact with the drain electrode, a passivation layer for protecting the thin film transistor, a pixel electrode electrically contacting the drain electrode through the first contact hole formed in the passivation layer, and a second contact hole formed on a surface of the passivation layer. It is provided with a link electrode for electrically connecting the data line and the source electrode through the It features.

According to an aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, the method comprising: providing a groove in which signal wiring is to be formed on a transparent substrate; Forming a gate insulating film and an active layer sequentially on the transparent substrate; forming a source and a drain electrode of the thin film transistor on the active layer so as to overlap the data line; and forming a protective film on the transparent substrate. And forming contact holes together with the active layer and the gate insulating layer, and forming a pixel electrode contacting the drain electrode through the first contact hole among the contact holes.

Other objects and features of the present invention in addition to the above objects will become apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 4A to 12.

4A through 11 are cross-sectional views and plan views illustrating a method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention.

4A through 4E, the trench 36 is formed on the transparent substrate 32 to simultaneously form the gate electrode 40, the data line 42, and the gate line 44 as illustrated in FIG. 5. Done. In detail, as shown in FIG. 4A, the photoresist is coated on the transparent substrate 32 and then patterned using a first mask to form the photoresist pattern 34. By etching the transparent substrate 32 exposed through the photoresist pattern 34, a trench 36 is formed as shown in FIG. 4B. Next, as shown in FIG. 4C, a metal material such as Mo, Cu, Pd, Au, or the like is applied by sputtering to form the metal seed layer 38. In this case, when the trench 36 is formed by the wet etching method, the metal seed layer 38 is formed by the sputtering method, whereas the catalyst metal layer may be formed by the dry etching method. When the metal seed layer 38 is formed, the photoresist pattern 34 on the transparent substrate 32 is removed as shown in FIG. 4D. Subsequently, a low resistance metal material such as Cu, Ag, Au, or the like is plated only on the trench 36 of the transparent substrate 32 on which the metal seed layer 38 is formed by using an electroless plating method. The gate line 42 and the data line 44 are formed. The gate electrode 40, the gate line 42, and the data line 44 are formed to have the same surface as the transparent substrate 32. In other words, the gate line 44, the gate electrode 40, and the data line 42 are formed on the transparent substrate 32 without the stepped portion. The gate line 44 and the data line 42 are not shorted as shown in FIG. 5.

6 and 7, the gate insulating film 46, the active layer 48, and the gate electrode 40, the gate line 42, and the data line 44 are sequentially formed on the transparent substrate 32. The ohmic contact layer 50 and the source and drain electrodes 52 and 54 are formed. In detail, the gate insulating layer 46, the active layer 48, and the ohmic contact layer 50 are formed on the surface of the transparent substrate 32 on which the gate electrode 40, the gate line 42, and the data line 44 are formed. It is formed sequentially. Subsequently, after depositing a low-resistance metal material such as Mo and Cr on the ohmic contact layer 50, the metal layer and the ohmic contact layer 50 are patterned in the same form using a second mask. As such, the patterned metal layer forms the source and drain electrodes 52 and 54 and the storage electrode 56 as shown in FIG. 7. Here, one end of the source electrode 52 is formed to overlap one end of the data line 42.

8 and 9, the protective layer 60 is formed and patterned on the substrate. In detail, when the source and drain electrodes 52 and 54 and the storage electrode 56 are formed, the entire surface of the substrate is coated with an insulating material to form the passivation layer 60, and then the passivation layer and the active layer 48 using a third mask. ), The gate insulating layer 46 is sequentially patterned so as to remain only in the thin film transistor portion, the data line portion, and the pad portion. In this case, as shown in FIG. 9, the first contact hole 62 exposing the data line 42 and the source electrode 52, the second contact hole 64 exposing the drain electrode 54, and storage The third contact hole 66 exposing the electrode 56 is formed. In addition, a contact hole for exposing the data pad portion extending from the data line 42 and the gate pad portion extending from the gate line is formed. In this case, the gate insulating film 44 is selectively etched by adjusting the thickness of the photoresist using a half exposure mask. For example, in the gate line part, a half exposure mask is used to prevent the gate insulating layer 46 from being etched in order to prevent the gate line 44 from being damaged.

10 and 11, the entire surface of the transparent electrode material is deposited on the substrate on which the passivation layer 60 is formed, and then patterned by using a fourth mask. The drain electrode 54 is formed through the second contact hole 64. The pixel electrode 68 in contact with the film is formed. In this case, as shown in FIG. 12, a link electrode 70 electrically connected to the data line 42 and the source electrode 52 exposed through the first contact hole 62 is formed, and the pad portion is formed. It forms a transparent electrode in contact.

On the other hand, when the link electrode 70 made of a transparent electrode material has a large contact resistance between the data line 42 and the source electrode 52, a step of masking is added to form the link electrode 70 as a metal material. You may.

As described above, in the liquid crystal display device and the method of manufacturing the same, the data line and the gate line are formed in the trench formed on the transparent substrate without step so that the disconnection of the data line due to the conventional gate line step can be prevented. do. Accordingly, the liquid crystal display device and the manufacturing method thereof according to the present invention can be applied to a large panel because the failure rate due to disconnection of the data line can be minimized even when the gate line is formed thick.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (12)

A transparent substrate having a groove portion in which signal wiring is to be formed; A first metal pattern formed in a groove of the transparent substrate and forming a data electrode, a gate line, and a gate electrode of the thin film transistor; A second metal pattern including source and drain electrodes of the thin film transistor formed to overlap the data line; A gate insulating layer disposed between the first metal pattern and the second metal pattern; An active layer formed on a surface of the gate insulating layer and in contact with the source and drain electrodes; A protective film for protecting the thin film transistor, A pixel electrode electrically contacting the drain electrode through the first contact hole formed with the passivation layer; A link electrode formed on a surface of the passivation layer and electrically connecting the data line and the source electrode through a second contact hole; And a gate line and a data line formed in the groove portion are spaced apart from each other so as not to overlap each other. The method of claim 1, And the first metal pattern and the transparent substrate have the same surface. The method of claim 1, The second metal pattern may further include a storage electrode connected to the pixel electrode through a third contact hole to form a storage capacitor with the gate line. The method of claim 1, The link electrode is a liquid crystal display device, characterized in that any one of a transparent electrode and a metal electrode. Providing a groove in which signal wiring is to be formed on the transparent substrate; Forming a first metal pattern forming a data line, a gate line, and a gate electrode of the thin film transistor in a groove of the transparent substrate; Sequentially forming a gate insulating film and an active layer on the transparent substrate; Forming a source and a drain electrode of the thin film transistor so as to overlap the data line on the active layer; Forming a protective layer on the transparent substrate to pattern the active layer and the gate insulating layer together with forming a contact hole; Forming a pixel electrode in contact with the drain electrode through a first contact hole among the contact holes, And a gate line and a data line formed in the groove part are spaced apart from each other so as not to overlap each other. The method of claim 5, wherein The first metal pattern is a method of manufacturing a liquid crystal display device, characterized in that formed by the electroless plating method. The method of claim 6, Forming the first metal pattern And forming the first metal pattern after forming a metal seed layer in the groove when the groove is formed on the transparent substrate by a wet etching method. The method of claim 6, Forming the first metal pattern When the groove is formed on the transparent substrate by a dry etching method, forming a catalyst metal layer in the groove, and then forming the first metal pattern. The method of claim 5, wherein In the forming of the source and drain electrodes And forming a storage electrode contacting the pixel electrode through a second contact hole among the contact holes and forming a gate line and a storage capacitor at the same time. The method of claim 5, wherein In the step of patterning the passivation layer, the active layer, the gate insulating layer And selectively etching the gate insulating film according to a region using a half exposure mask. The method of claim 5, wherein In the forming of the pixel electrode And a link electrode contacting the data line and the source electrode through a third contact hole among the contact holes and made of a transparent electrode material such as the pixel electrode. The method of claim 5, wherein And forming a link electrode made of a metal material in contact with the data line and the source electrode through a third contact hole among the contact holes.

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