KR100674236B1 - Method of manufacturing fringe field switching liquid crystal display device - Google Patents

Abstract

The present invention relates to a method for manufacturing a fringe field driven liquid crystal display device, wherein the method for manufacturing a fringe field driven liquid crystal display device includes providing a transparent insulating substrate in a unit pixel area defined by a gate bus line and a data bus line. Forming a plurality of counter electrodes by depositing a transparent conductor on a transparent insulating substrate and patterning a predetermined portion; depositing a metal film on the counter electrode and patterning the predetermined portion to form a common electrode connected to the gate bus line and the counter electrode. Forming a gate insulating film covering an entire surface of an insulating substrate including a counter electrode, a gate bus line, and a common electrode; and sequentially forming a channel layer and a source / drain electrode, and then including a channel layer and a source / drain electrode. Forming a protective film covering the entire surface of the insulating substrate, the gate insulating film and Patterning a thin film to expose a corresponding insulating substrate between the counter electrodes, forming a transparent conductive film covering the upper surface of the protective film and the exposed insulating substrate, and patterning the transparent conductive film to form a top surface of the insulating substrate exposed between the counter electrodes. Forming a pixel electrode insulated from the counter electrode. Therefore, the afterimage factor generated by the overlap of the counter electrode and the pixel electrode can be eliminated, and the transmittance can be improved and the response speed of the liquid crystal can be increased.

Description

Method for manufacturing fringe field driven liquid crystal display device {METHOD OF MANUFACTURING FRINGE FIELD SWITCHING LIQUID CRYSTAL DISPLAY DEVICE}

1 is a plan view for explaining a method for manufacturing a fringe field drive liquid crystal display device according to the prior art.

2 is a cross-sectional view illustrating a method of manufacturing a fringe field drive liquid crystal display device according to the prior art.

3 is a cross-sectional view illustrating a method of manufacturing a fringe field drive liquid crystal display device according to the present invention;

<Explanation of symbols for main parts of drawing>

10: lower glass substrate 11: gate electrode

12: common electrode 14a: drain electrode

14b: source electrode 15: thin film transistor

16: gate insulating film 17: counter electrode

18: protective film 19: pixel electrode

20: upper glass substrate

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for manufacturing a fringe field drive liquid crystal display device. In particular, a fringe field drive liquid crystal display which removes image sticking by decentralizing a field applied to a pixel and preventing deterioration of a protective layer An apparatus and a method of manufacturing the same.

Fringe-field driven liquid crystal displays have been proposed to improve the low aperture and transmittance of in-plane driven liquid crystal displays.

In the fringe field driving liquid crystal display, the counter electrode and the pixel electrode are formed of a transparent metal film, for example, indium tin oxide (ITO), and the counter electrode and the pixel electrode are formed to be smaller than the gap between the upper and lower substrates. And a parabolic electric field, that is, a fringe field, is formed on the pixel electrode.

1 is a plan view schematically illustrating a lower array substrate of a fringe field driving liquid crystal display device according to the related art.

As shown in Fig. 1, the gate bus line 11 and the data bus line 13 are arranged in an arrangement so that unit pixels are defined, and the TFT 15, which is a switching element, is arranged at the intersection. A counter electrode 17 made of a transparent conductor is disposed in the unit pixel, and the pixel electrode 19 is disposed in the unit pixel so as to overlap the counter electrode 17. The pixel electrode 19 is also made of a transparent conductor and is electrically insulated from the counter electrode 17. The pixel electrode 19 is in the shape of a comb teeth parallel to the data bus line 13 and spaced at a predetermined interval, and a part of the pixel electrode 19 is formed by a drain electrode (not shown) of the TFT 15. It is connected.

2 is a cross-sectional view schematically illustrating a lower array substrate of a fringe field driving liquid crystal display device according to the related art.

As shown in FIG. 2, the fringe field driving liquid crystal display includes a counter electrode 17 on a transparent insulating substrate, for example, a lower glass substrate 11, and a gate insulating film 16 and a protective film 18. The pixel electrodes 19 are spaced apart from each other so as to overlap the counter electrode 17. In addition, a TFT 15 including source and drain electrodes 14a and 14b is disposed as a switching element.

Here, the lower glass substrate 10 and the upper glass substrate 20 are disposed to face each other at a predetermined distance under the interposition of the liquid crystal layer (not shown). At this time, the gap between the lower glass substrate 10 and the upper glass substrate 20 is called a cell gap, which is larger than the gap between the counter electrode 17 and the pixel electrode 19, so that the positive electrode 17 A fringe field (shown by two curved dashed lines) is formed between (19).

In the conventional fringe field driving liquid crystal display as described above, the fringe field is formed between the counter electrode 17 and the pixel electrode 19, as described above, between the upper and lower glass substrates 10 and 20. The liquid crystal molecules having negative dielectric anisotropy characteristics interposed therebetween operate so that all the light passes through the polarizer (not shown) to realize high brightness and wide viewing angle.

 However, the fringe field drive liquid crystal display device has better viewing angle, aperture ratio and transmittance than TN (Twisted Nematic) and IPS mode TFT-LCD, but the fringe field is concentrated on the protective film, resulting in excessive charge in the protective film. Concentration (deterioration). There is a problem that an afterimage occurs due to deterioration of the protective film.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and an object of the present invention is to form a hole in a gate insulating film and a protective film disposed below the pixel electrode, and to apply an electric field applied to the insulating film between the counter electrode and the pixel electrode. It is to provide a method of manufacturing a fringe field drive liquid crystal display device that can reduce the.

According to another aspect of the present invention, there is provided a method of manufacturing a fringe field driving liquid crystal display device, the method including: providing a transparent insulating substrate in a unit pixel area defined by a gate bus line and a data bus line; Depositing a transparent conductor on a substrate and then patterning a predetermined portion to form a plurality of counter electrodes; depositing a metal film on the counter electrode and then patterning a predetermined portion to form a common electrode connected to the gate bus line and the counter electrode Forming a gate insulating film covering the entire surface of the insulating substrate including a counter electrode, a gate bus line, and a common electrode; and sequentially forming a channel layer and a source / drain electrode, and then forming a gate insulating film including the channel layer and the source / drain electrode. Forming a protective film covering the entire surface; patterning the gate insulating film and the protective film Exposing a corresponding insulating substrate between the counter electrodes, forming a transparent conductive film covering the upper surface of the protective film and the exposed insulating substrate, and patterning the transparent conductive film to form a counter electrode on the upper surface of the insulating substrate exposed between the counter electrodes. Forming a pixel electrode insulated from the substrate.

Hereinafter, a method of manufacturing a fringe field drive liquid crystal display device according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a cross-sectional view illustrating a method of manufacturing a fringe field drive liquid crystal display device according to the present invention.

In the method of manufacturing a fringe field driving liquid crystal display device according to the present invention, as shown in FIG. 3, in a unit pixel area divided by a gate bus line and a data bus line, a transparent insulating substrate, for example, The lower glass substrate 10 is prepared.

After that, any one of a group consisting of aluminum (Al), molybdenum (Mo), titanium (Ti), tungsten (W), tantalum (Ta), chromium (Cr), a combination thereof, and the like on the lower glass substrate 10 One metal film is deposited and patterned to form a gate electrode 11 and a common electrode 12. Then, a counter electrode is formed, and the common electrode 12 is brought into contact with the counter electrode 17. Here, after forming the counter electrode 17, the step of forming the gate electrode 11 and the common electrode 17 may be performed first.

Subsequently, a gate insulating film 16 is formed on the lower glass substrate 10 on which the gate electrode 11, the common electrode 12, and the counter electrode 17 are formed.

Next, a channel layer is formed on a portion of the gate insulating layer 16 corresponding to the gate electrode 11, and a drain electrode 14a and a source electrode 14b are formed on the upper surface of the channel layer. One end of the drain electrode 14a is connected to the data line, and the other end of the drain electrode 14a is connected to the channel layer. The source electrode 14b is spaced apart from the drain electrode 14a by a predetermined distance and one end thereof contacts the channel layer.
Subsequently, silicon nitride (SiNx) or the like is deposited on the entire surface of the lower glass substrate 10 including the source electrode 14b and the drain electrode 14a using a plasma enhanced chemical vapor deposition method. 18). After the formation of the passivation layer 18, holes are formed in the passivation layer to correspond to the other end of the source electrode 14b so that the pixel electrode 19 to be described later is contacted. In this case, as shown in FIG. 3, the passivation layer 18 and the gate insulating layer 16 positioned at the portions corresponding to the counter electrodes 17 are also etched at once to remove the lower glass substrate 10 between the count electrodes 17. Expose
In other words, the gate insulating layer 16 and the passivation layer 19 are removed by etching, for example, between the predetermined portion and the counter electrode. In this case, the drain electrode 14b and the pixel electrode 19 to be described later are contacted. Since the copper shape can be patterned when forming holes to be added, additional process and mask addition are not required. In this case, the protective layer 18 may be etched and removed, and the gate insulating layer 16 may be left in the etching process for coplanar or spatial configuration with the counter electrode 19. In addition, the gate insulating layer 18 and the passivation layer 19 positioned at the boundary between the pixel electrode 19 and the gate line 11 or the data line (not shown) are simultaneously removed to remove the pixel electrode 19 and the gate. The parasitic capacitance factor between lines 11 or data (not shown) lines can be reduced.
When a portion of the protective film and the gate insulating film are removed in this manner, the transparent conductor is deposited on the upper surface of the protective film 18 including the lower glass substrate 10 exposed between the count electrodes 17, and then the transparent conductor. 3, the pixel electrode 19 is formed between the count electrodes 17, that is, on the exposed lower glass substrate 10 of the gate insulating layer 16 and the passivation layer 18, as shown in FIG. 3. In this case, indium tin oxide (ITO) is generally used as the transparent conductor.
The pixel electrodes formed between the count electrodes are interconnected by portions formed in the same direction as the gate lines in portions corresponding to the gate lines as shown in FIG. 1.

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In the fringe field driving liquid crystal display, the counter electrode 17 and the pixel electrode 19 are formed of a transparent conductor on the same lower glass substrate 11, and the gap between the two electrodes 17 and 19 is defined as a cell gap. It is made smaller so that a parabolic electric field, that is, a fringe field, is formed. Therefore, when an electric field is applied between the positive electrodes 17 and 19, all liquid crystal molecules (not shown) on the positive electrodes 17 and 19 are operated to operate the conventional liquid crystal display device. Compared with this, the transmittance is greatly improved.

However, when implementing the same shape for a long time, the amount of charge applied to the liquid crystal is asymmetrical. As a result, the direct current component applied to the liquid crystal and each of the insulating films 16 and 18 is represented as charge accumulation in the gate electrode, the data electrode, and the pixel electrode. Due to the charge accumulation effect, the orientation of the liquid crystal is distorted than the initial value, which acts as a factor of degrading the product quality.

Therefore, the protective film 18 and the gate insulating film 16 positioned below the pixel electrode 19 where the fringe field is concentrated during liquid crystal driving are removed, and in particular, vertically as in the conventional fringe field driving liquid crystal display device. The electric field of the direction is applied, and the factor which concentrates an electric charge on an insulating film can be reduced significantly. That is, the electric field applied to the insulating film acts horizontally, and the electric field value applied in the horizontal direction becomes very small as compared with the vertical direction.

Therefore, the present invention disclosed herein eliminates the deterioration factor of the pixel due to the parasitic capacitance and the deterioration factor of the insulating film due to the conventional vertical electric field as described above. It is to provide a method of eliminating afterimage factors caused by overlapping.

After removing the gate insulating layer and the protective layer, forming the pixel electrode, bonding the upper substrate with the color filter to the lower substrate, and then injecting the liquid crystal, one liquid crystal cell is completed. Here, the process for the alignment film, the color filter, the upper substrate, the polarizing plate, and the like can be sufficiently predicted by those skilled in the art, and those skilled in the art, so the detailed description will be omitted here.

On the other hand, the fringe field drive liquid crystal display device and the method of manufacturing the same according to the embodiment of the present invention is not limited to the above embodiment can be carried out in various modifications within the scope not departing from the gist of the invention.

As described above, the fringe field drive liquid crystal display device and the manufacturing method thereof according to the present invention have the following effects.

The present invention provides a method for eliminating afterimage factors caused by overlapping of counter electrodes and pixel electrodes, which are conventionally applied in fringe field driving liquid crystal displays, and deterioration factors and / or parasitic capacitances of insulating films due to vertical electric fields. It is possible to solve the problem that an afterimage occurs by reducing or eliminating a deterioration factor of a pixel.                     

In addition, no additional process or mask is required when forming the structure to solve the above problem, and the area where the counter electrode and the pixel electrode overlap is reduced, thereby improving transmittance and increasing the response speed of the liquid crystal.

Claims (6)

In a unit pixel area defined by a gate bus line and a data bus line, Providing a transparent insulating substrate; Depositing a transparent conductor on the transparent insulating substrate and then patterning a predetermined portion to form a plurality of counter electrodes; Depositing a metal film on the counter electrode and patterning a predetermined portion to form a gate bus line and a common electrode connected to the counter electrode; Forming a gate insulating film covering an entire surface of the insulating substrate including the counter electrode, a gate bus line, and a common electrode; Sequentially forming a channel layer and a source / drain electrode, and then forming a passivation layer covering an entire surface of the insulating substrate including the channel layer and the source / drain electrode; Patterning the gate insulating layer and the passivation layer to expose the insulating substrate corresponding to the counter electrode; Forming a transparent conductive film covering an upper surface of the passivation layer and the exposed insulating substrate; And And patterning the transparent conductive film to form a pixel electrode insulated from the counter electrode on an upper surface of the insulating substrate exposed between the counter electrodes. The method of claim 1, And removing the gate insulating film and the passivation film in parallel with the formation of a contact hole between the pixel electrode and the source electrode. The method of claim 1, And removing the gate insulating film and the protective layer formed between the pixel electrode and the gate line in parallel with the removal of the gate insulating film and the protective film. The method of claim 1, And a width of a region between the gate insulating film and the counter electrode from which the protective film is removed is formed within 5 μm. The method of claim 1, And a thickness of the pixel electrode is 200 mu m or more. The method of claim 1, wherein the pixel electrode formed on the passivation layer is formed to overlap the counter electrode.

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