KR100237680B1 - Lcd device and its manufacturing method - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display and a method of manufacturing the same, wherein a pixel electrode is formed in a pixel region defined by a gate line and a data line on a transparent insulating substrate, and the pixel electrode includes at least a first pixel electrode and a second pixel electrode. An edge portion of one of the first pixel electrode and the second pixel electrode overlaps the gate line or the data line. In addition, the first pixel electrode and the second pixel electrode are in contact with the area in the pixel area, and are separated by an insulating film at a portion overlapping the gate line or the data line. Therefore, the plurality of pixel electrodes do not cause short defects through the insulating film, and at the same time, they may have a sufficient distance from neighboring pixel electrodes formed in the same layer, so that the process margin may be sufficient during manufacturing, thereby increasing the process yield. By forming the width of the gate line and the data line optimally and the display area of the portion excluding the optimal wiring width, the aperture ratio can be increased, thereby forming a pixel electrode having a step in the pixel region. A wide viewing angle can be realized.

Description

Liquid Crystal Display and Manufacturing Method Thereof

The present invention relates to a liquid crystal display device and a manufacturing method thereof, and more particularly, to a liquid crystal display device and a method of manufacturing the same to implement a wide viewing angle and ultra-opening ratio.

In general, liquid crystal displays have been researched on technologies for widening the viewing angle due to the nature of liquid crystal molecules, and black matrices for blocking gate lines, data lines, thin film transistors, and light leakage are formed on a substrate where pixels are formed. As a result, research to improve the aperture ratio has been chiefly developed.

First, as a method of implementing a wide viewing angle, a double domain twisted nematic (DDTN) method and a method of adding a phase difference film are being applied.

The DDTN method is a method in which the first alignment layer and the second alignment layer are formed in each unit pixel, and the orientation direction is changed by varying rubbing in each alignment layer.

In such a conventional liquid crystal display and a manufacturing method thereof, each unit pixel has a different alignment direction so that the vertical mode and the left and right modes are repeated in pixel units. As a result, the problem of imbalance between the vertical, horizontal, left and right viewing angles is solved, thereby increasing the viewing angle.

In addition, a method of using a retardation film is a method of changing a phase of light passing through an area in a unit pixel by using a retardation film.

However, in the former case, the process is increased, and in the latter case, the cost is increased.

In addition, in order to improve the aperture ratio, the width of the black matrix and the size of the thin film transistor to minimize data lines, gate lines, and light leakage formed in the pixel region should be minimized. There is a limit to the reduction.

Next, a conventional technology will be described with reference to the accompanying drawings.

1 is a plan view illustrating a structure of a thin film transistor substrate of a liquid crystal display according to the related art.

As shown in FIG. 1, the gate line 1 is formed in a horizontal direction, and a data line 2 intersecting with the gate line 1 and defining the pixel P is formed, and the pixel region P is formed. In the center of the capacitor electrode 12 is formed in parallel with the gate line (1). The gate electrode 11 which is a part of the gate line 1, the source electrode 21 and the drain electrode 22 which are part of the data line 2, and the semiconductor layer are formed at the intersection of the gate line 1 and the data line 2. A thin film transistor TFT formed of (3) is formed, and an etch stopper 9 is formed between the source electrode 21 and the drain electrode 22. In the pixel region P, a first pixel electrode 5 having an edge portion partially overlapped with the gate line 1 and the data line 2 is formed. A first electrode connected to the source electrode 21 and extending from the source electrode 21 to overlap the storage capacitor electrode 12, and connected to the first pixel electrode 5 through two contact holes 7. Two pixel electrodes 6 are formed.

In the conventional method of manufacturing a liquid crystal display, first, the gate line 1, the gate electrode 11, and the storage capacitor electrode 12 are formed, and then a gate insulating film (not shown) is formed. Subsequently, an insulating film and a silicon layer are deposited and the insulating film is patterned to form an etch stopper 9, the silicon layer is etched to form a semiconductor layer 3, and then an edge of the gate line 1 to form a gate pad. A portion of the gate insulating film (not shown) formed thereon is etched. Next, ITO is deposited and patterned to form a second pixel electrode 6, and a metal film is deposited and patterned to form a data line 2, a source electrode 21, and a drain electrode 22. An organic insulating film having a low dielectric constant is deposited to form a protective film (not shown), and a portion of the protective film (not shown) is etched to form a contact hole 7 on the second pixel electrode 6. Finally, ITO is deposited and patterned to form the first pixel electrode 5.

However, such a conventional liquid crystal display and its manufacturing method require an eight-step photo process, and in order to increase the aperture ratio, strict process control is required to form the first pixel electrode overlapping the gate line and the data line, and thus the process yield is lowered. I have a problem. In addition, since the pixel electrodes formed on the gate line and the data line are adjacent to each other, a short defect occurs.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a liquid crystal display device which realizes an ultra-opening ratio of about 80% and realizes a wide viewing angle and improves process yield by a six-step photo process.

1 is a plan view illustrating the composition of a thin film transistor substrate of a liquid crystal display according to the related art.

2 is a plan view illustrating a structure of a liquid crystal display according to an exemplary embodiment of the present invention.

3 is a cross-sectional view showing a portion A in detail in FIG.

4 is a cross-sectional view showing in detail the portion B in FIG.

5 is a cross-sectional view illustrating a method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention.

In the liquid crystal display according to the present invention, a pixel electrode is formed in a pixel region defined as a gate line and a data line on a transparent insulating substrate, and the pixel electrode includes at least a first pixel electrode and a second pixel electrode. An edge portion of one of the first pixel electrode and the second pixel electrode overlaps the gate line or the data line. In addition, the first pixel electrode and the second pixel electrode are in contact with the area in the pixel area, and are separated by an insulating film at a portion overlapping the gate line or the data line.

A thin film transistor including a gate electrode that is part of the gate line, a drain electrode that is part of the data line, and a source electrode is formed at a portion where the gate line and the data line cross each other.

In addition, one of the first pixel electrode and the second pixel electrode overlapping the gate line and the data line around the edge is connected to the source electrode through a contact hole formed in the insulating layer.

One of the first pixel electrode and the second pixel electrode is formed on the thin film transistor via an insulating film.

Here, since the insulating film is an organic insulating film having a low dielectric constant, it does not affect the characteristics of the thin film transistor.

In addition, the area where the first pixel electrode and the second pixel electrode contact each other has a plurality of widths.

The edge portion of the second pixel electrode is formed in the pixel area so that the edge portion overlaps the gate line or data line and the first pixel electrode, and the edge portion of the first pixel electrode does not overlap the gate line or data line. In the portion not overlapping with the gate line or data line, the edge portion of the second pixel electrode overlaps the gate line or data line.

In the liquid crystal display according to the present invention, since the first pixel electrode and the second pixel electrode are separated from each other by the insulating layer on the upper and lower portions of the data line with the data line as the pixel electrode of the pixel region, the width of the data line is minimized. Even if the short-circuit does not occur with the pixel electrodes of the neighboring pixel regions.

In addition, since the gate lines are formed in the same structure, short defects with neighboring pixel electrodes do not occur even when the width of the gate lines is minimized.

In addition, all parts except the width of the optimal data line and the gate line become the display area displayed as an image.

Since the area where the first pixel electrode and the second pixel electrode are in contact has a plurality of widths, a step is formed in the pixel area to obtain a wide viewing angle by reducing the rotational dispersion effect.

In the method of manufacturing a liquid crystal display according to the present invention, a first pixel electrode is formed by depositing ITO on a transparent insulating substrate, an insulating film covering the first pixel electrode is formed, and a gate line and a gate line are connected on the insulating film. A gate electrode, a gate insulating film covering the gate line and the gate electrode and a silicon layer are formed, the silicon layer is etched to form an active layer, a data line intersecting the gate line, and a drain electrode and a source electrode are formed. To form a thin film transistor, a protective film is formed on the substrate, and a second pixel electrode is formed on the protective film.

The insulating film and the protective film may be formed by a PECVD method, a sputtering method or a coating method using an organic insulating film.

Before forming the second pixel electrode, a portion of the passivation layer, the insulating layer, and the gate insulating layer is etched to form an opening having an inclined surface and a different width, and a contact hole is formed on the source electrode to form the second pixel electrode and the first pixel. Connect the pixel electrode.

When the protective film and the insulating film are formed of an organic insulating film having a low dielectric constant, the second pixel electrode is formed up to the upper portion of the thin film transistor.

The second pixel electrode and the first pixel electrode are formed to be separated from each other by an insulating film and a protective film at a portion overlapping the gate line or the data line.

In the method of manufacturing the liquid crystal display device according to the present invention, forming the first pixel electrode, forming the gate line and the gate electrode, forming the active layer of the thin film transistor, and forming the data line, the source and the drain electrode The process of forming the opening, the contact hole, and the forming of the second pixel electrode are performed in six steps.

In addition, the first pixel electrode and the second pixel electrode are separated from each other by the insulating layer and the passivation layer on the upper and lower portions of the gate line and the data line to form one pixel electrode, thereby not requiring a strict process margin during manufacturing.

Next, an embodiment of a liquid crystal display and a manufacturing method according to the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily practice the present invention.

FIG. 2 is a plan view illustrating a structure of a liquid crystal display according to an exemplary embodiment of the present invention, FIG. 3 is a cross-sectional view showing part A in FIG. 2 in detail, and FIG. 4 is a detail view showing part B in FIG. It is a cross section.

As shown in FIG. 2, in the liquid crystal display according to the exemplary embodiment, the gate line 200 is formed in the horizontal direction on the transparent insulating substrate 100 and the data line 300 intersects with the gate line 200. It is formed vertically. A thin film including a gate electrode 20 having a portion of the gate line 200, a drain electrode 30 having a portion of the data line 300, and a source electrode 40 at a portion where the gate line 200 and the data line 300 cross each other. The transistor TFT is formed. In the portion defined by the gate line 200 and the data line 300, a pixel electrode 130 formed of an ITO film having an edge portion overlapping the gate line 200 and the data line 300 is formed, and a source electrode 40 is connected to the pixel electrode 130 through the contact hole 110.

Here, the pixel electrode 130 is formed by separating the first pixel electrode 131 and the second pixel electrode 132, and most of the pixel electrodes 130 overlap each other, and a portion D indicated by a dotted line in the pixel area is a first pixel electrode ( The portion where the 131 and the second pixel electrode 132 are in contact with each other is shown. The right edge portion of the first pixel electrode 131 partially overlaps the data line 300, and the remaining peripheral portion is formed in the pixel area. The second pixel electrode 132 partially overlaps the data line 300 and the gate line 200 adjacent to the left edge portion and the upper edge portion.

3 is a cross-sectional view illustrating a portion A of FIG. 2 in detail, and illustrates the relationship between the first pixel electrode 131 and the second pixel electrode 132 in more detail.

The second pixel electrode 132 and the data line 300 are formed on the portion of the substrate 100 through the insulating film 50 and the gate insulating film 60, and the passivation film 70 covering the data line 300 is formed by the gate. It is formed on the insulating film 60. Here, the opening C having an inclined surface formed at an angle is formed in the insulating film 50, the gate insulating film 60, and the protective film 70, and the first pixel electrode formed on the inclined surfaces of the protective film 70 and the opening Y. 131 is in contact with the second pixel electrode 132 through the opening C. The right end portion of the first pixel electrode 131 partially overlaps the data line 300 formed under the passivation layer 70, and the left end portion of the second pixel electrode 132 is formed of an insulating film 50 and A portion of the neighboring data line 300 formed on the upper portion of the gate insulating layer 60 is overlapped.

FIG. 4 is a cross-sectional view illustrating a portion B of FIG. 2 in detail and illustrates a relationship between a neighboring data line 300, a first pixel electrode 131, and a second pixel electrode 132.

The first pixel electrode 131 formed on the passivation layer 70 is spaced apart from the neighboring first pixel electrode 131 on the neighboring data line 300 and is adjacent to the neighboring first pixel electrode 131. The left portion of the neighboring data line 300 formed below overlaps, and the right portion of the neighboring data line 300 overlaps the second pixel electrode 132 formed below. As described above, the first pixel electrode 131 and the second pixel electrode 132 are in contact with each other through the opening C having the inclined surface.

Herein, if the distance from the right end of the neighboring data line 300 to the right end of the neighboring first pixel electrode 131 is Y and the distance between the separated first pixel electrodes 131 is X, X Even if the distance is sufficiently far to give a sufficient process margin, the display can be performed using the second pixel electrode 132 formed under the data line 300. Therefore, even if the width of the data line 300 is optimally formed, the portion actually displayed can be subtracted only by the width of the data line 300, thereby maximizing the aperture ratio. Even if the distance Y from the neighboring pixel electrode 130 is sufficiently small, the insulating film 50, the gate insulating film 60, and the protective film 70 are provided between the first pixel electrode 131 and the second pixel electrode 132. The problem that short defects occur can be excluded.

This structure is equally applied to the portion overlapping with the gate line 200, so that even if the gate line 200 and the data line 300 are optimally formed, all areas are displayed except for the portion where the wirings 200 and 300 pass. The area can be as large as possible to realize the maximum display area.

In addition, the liquid crystal display according to the present invention is not limited to the structure according to the embodiment, and alternately overlaps with the gate line and the data line by using the first pixel electrode and the second pixel electrode, and overlaps the gate line and the data. The structure which can make all the pixel area defined by a line as a display area is possible.

In addition, since the first pixel electrode 131 and the second pixel electrode 132 are connected to each other through the openings of the insulating film 50 and the gate insulating film 60 and the passivation film 70 in the pixel region 130, the inclination of the pixel area 130 may be reduced. Branch is formed a step, thereby giving a phase difference of the incident light, thereby widening the viewing angle.

The manufacturing method of the liquid crystal display device according to the present invention is performed as follows.

5 is a cross-sectional view illustrating a method of manufacturing a liquid crystal display according to an exemplary embodiment of the present invention according to a process sequence thereof.

As shown in FIG. 5A, a method of manufacturing a liquid crystal display according to the present invention deposits indium tin oxide (ITO) using a sputtering method on a transparent insulating substrate 100, uses a first mask, and is patterned. After etching, the second pixel electrode 132 is formed.

Next, as shown in FIG. 5B, an insulating film 50 covering the second pixel electrode 132 is deposited. The insulating film 50 may be formed by a PECVD method, a sputtering method or a coating method using an organic insulating film.

Subsequently, as shown in FIGS. 5C to 5D, a metal film is deposited on the substrate 100, and the gate line 200 and the gate electrode 20 are formed by using a second mask and patterning and etching. Subsequently, a nitride film as the gate insulating film 60, an undoped amorphous silicon layer, and a heavily doped amorphous silicon are sequentially deposited on the substrate 100 using the PECVD method. Subsequently, the semiconductor layer 80 and the contact layer 90 are formed by simultaneously etching the high concentration amorphous silicon layer and the undoped amorphous silicon layer using the active mask as the third mask. Subsequently, a metal film is deposited on the substrate 100, and the metal film is patterned using an S / D mask, which is a fourth mask, to form two electrodes 30 and 40, and the exposed contacts using the two electrodes 30 and 40 as masks. A portion of the layer 90 is etched to form a thin film transistor (TFT).

Next, as shown in FIGS. 5E to 5F, a passivation layer 70 is formed on the substrate 100 and the passivation layer 70 is formed between the source electrode 40 and the neighboring data line 300 using a fifth mask. A portion of the gate insulating film 60 and the insulating film 50 is etched to open the opening C to expose the second pixel electrode 132 formed on the substrate 100. In this case, the opening C is formed in the same manner as the portion D shown by the dotted line in FIG. 2, and the side surface forming the opening C is formed to be inclined smoothly. The protective film 70 may be formed by a PECVD method, a sputtering method, or a coating method using an organic insulating film, similarly to the insulating film 50.

Finally, ITO is deposited on the substrate 100 using a sputtering method, and the first pixel electrode 131 is formed by patterning and etching using a sixth mask.

In the method of manufacturing the liquid crystal display device according to the present invention, the first pixel electrode 131 is formed, the gate line 200 and the gate electrode 20 are formed, and the semiconductor layer 80 of the thin film transistor TFT is formed. ) And forming the contact layer 90, forming the data line 300, the source and drain electrodes 30 and 40, forming the opening C and the contact hole 110, and the second pixel. Only in forming the electrode 132, a pattern process using a mask is performed.

The first pixel electrode 131 and the second pixel electrode 132 are disposed on the upper and lower portions of the gate line 200 and the data line 300 through the insulating film 50, the gate insulating film 60, or the protective film 70. ) Are separated from each other to form one pixel electrode 130, so that a strict process margin is not required in manufacturing.

Accordingly, in the liquid crystal display and the method of manufacturing the same according to the present invention, short circuits can be prevented by forming pixel electrodes through an insulating film, and at the same time, a sufficient margin is provided by sufficient gap between some pixel electrodes formed in the same layer. As a result, the process yield can be improved, and the aperture ratio can be increased by using a portion except for the width of the gate line and the data line as the display area, and a wide viewing angle can be realized by forming a pixel electrode having a step difference.

Claims (4)

A transparent insulating substrate, a pixel region defined as a data line intersecting a gate line and the gate line on the substrate, a gate electrode that is a part of the gate line, a drain electrode as part of the data line, and a source electrode at a portion where the gate line and the data line intersect A thin film transistor comprising: an insulating film having an inclined surface according to a change in thickness, an insulating film having an opening in the pixel region, and a first pixel electrode formed over the insulating film of the pixel region. The liquid crystal display of claim 1, wherein the opening has a plurality of widths. The liquid crystal display of claim 1, wherein the insulating layer includes organic insulation having a low dielectric constant. The display device of claim 1, further comprising a second pixel electrode connected to the first pixel electrode through the opening of the insulating layer, and overlapping at least a portion of the first pixel electrode. And an edge portion of at least one of the gate lines and the data lines overlapping the gate line.