KR101058669B1 - Liquid crystal display device and manufacturing method thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a method of manufacturing the same, and includes a lower substrate, an upper substrate, and a liquid crystal layer interposed between the substrates, and a plurality of gate lines and data lines intersecting each other on the lower substrate. Each pixel region is defined by a pixel, and a switching element is disposed in an intersection area of the gate line and the data line, and a region in which the switching element is disposed is provided with a certain type of active layer and a source / drain electrode. First and second transparent electrodes disposed in the pixel area and spaced apart from each other to overlap a predetermined area in order to control an amount of light transmission by applying an electric field to the liquid crystal layer, and interposed between the data line and the gate line. A second section formed between the formed first insulating film and the data line and the second transparent electrode Including a soft film, wherein the first insulating film includes an upper insulating film and a lower insulating film, the first transparent electrode is formed between the upper insulating film and the lower insulating film, it is easy to secure the auxiliary capacitance and the aperture ratio and the outdoor visibility There is an improvement effect.

 Low temperature polysilicon, auxiliary capacitance, insulating film

Description

Liquid crystal display and its manufacturing method {A LIQUID CRYSTAL DISPLAY AND FABRICATION METHOD OF THE SAME}

The present invention relates to a liquid crystal display and a method for manufacturing the same. More particularly, it is possible to easily form a storage capacitor by adjusting the deposition thickness of the insulating film between the transparent common electrode and the data line, and to improve the aperture ratio and the internal reflection effect. A liquid crystal display device and a manufacturing method thereof.

In general, the display mode of a liquid crystal display (LCD) is largely divided into a twisted nematic (TN), a transverse electric field method, or a vertical alignment method (VA) for the purpose of wide viewing angle and high gradation. This exists.

Among these, the transverse electric field is represented by In-Plane Switching (IPS) or FFS (Fringe Field Switching).

In the case of applying a TFT device formed of polysilicon (p-Si), for example, Low Temperature Poly-Si (LTPS) in the FFS method, an oxide (Silicon Oxide) is used as an insulating film for forming the auxiliary capacitance. ) -Based silicon (eg, SiO ₂ or SiON, etc.) is used, which makes it difficult to form the auxiliary capacitance as compared with the case where an a-Si type TFT device is applied.

1A and 1B are cross-sectional views illustrating a conventional liquid crystal display device.

Referring to FIG. 1A, FIG. 1A is a cross-sectional view of a predetermined region of a data line of a conventional liquid crystal display. For example, a gate insulating layer 110 is formed on a substrate 100 on which a buffer layer B is formed. The common electrode 120 is formed on the upper portion 110. In addition, the first insulating layer 130 is formed on the common electrode 120, and the data line 140, the second insulating layer 150, and the pixel electrode 160 are sequentially formed on the first insulating layer 130. Is formed.

In this case, oxide-based silicon is typically used as the first insulating film 130, and nitride-based silicon is used as the second insulating film 150.

In this case, since the dielectric constant of the oxide-based silicon is smaller than that of the nitride-based silicon (about 6.0 to 7.0), the polysilicon liquid crystal containing the oxide-based silicon as an insulating film between the pixel electrode 160 and the common electrode 120. In the display device, it is difficult to form the storage capacitors by the first and second insulating layers 130 and 150 between the common electrode 120 and the pixel electrode 160 as compared to a liquid crystal display device using only silicon based nitride.

Meanwhile, referring to FIG. 1B, the liquid crystal display may form the common electrode 120 on the first insulating layer 130 to facilitate formation of the storage capacitor.

However, in this case, the formation of the storage capacitor is easy, but the data line 140 and the common electrode 130 are placed on the same layer, which may cause a short circuit defect between the data line 140 and the common electrode 120. Can be.

Therefore, in order to prevent such a short, a predetermined distance between the data line 140 and the common electrode 120 is required. However, this results in a decrease in the aperture ratio.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a liquid crystal display device capable of easily forming an auxiliary capacitance by a transparent pixel electrode and a transparent common electrode disposed with an insulating film interposed therebetween, and the manufacture thereof. To provide a method.

Another object of the present invention is to provide a liquid crystal display device and a method of manufacturing the same that can improve the aperture ratio and the internal reflection effect.

In order to achieve the above object, a first aspect of the present invention includes a lower substrate, an upper substrate, and a liquid crystal layer interposed between the substrates, and a plurality of data lines and gates formed on the lower substrate so as to cross each other. Each pixel region is defined by a line, and a switching element is disposed in an intersection area of the data line and the gate line, and a region in which the switching element is disposed is provided in a liquid crystal display device having a certain type of active layer and a source / drain electrode. A first and second transparent electrodes included in the pixel area and spaced apart from each other to overlap a predetermined area in order to control an amount of light transmission by applying an electric field to the liquid crystal layer; A first insulating film interposed between the data line and the gate line; And a second insulating film interposed between the data line and the second transparent electrode, wherein the first insulating film includes an upper insulating film and a lower insulating film, and the first transparent electrode is formed of the upper insulating film and the lower insulating film. It is to provide a liquid crystal display device which is formed between the intervening.

Here, a predetermined common bus line spaced apart from the gate line is formed on the same layer as the gate line, and a predetermined pattern is formed on the contact hole region formed to electrically connect the common bus line and the first transparent electrode. It is preferable that a reflecting plate having a further formed thereon.

Preferably, the reflective plate may be formed of the same material as a predetermined source / drain metal wiring formed to electrically connect the second transparent electrode and the source / drain electrode.

Preferably, the material forming the first insulating film may be a silicon oxide film.

Preferably, the material forming the second insulating film may be a silicon nitride film.

Preferably, the first insulating film may have a thickness of 3000 to 4000 kPa.

Preferably, the upper insulating film may have a thickness of 100 to 1000 kPa.

The second aspect of the present invention includes a lower substrate, an upper substrate, and a liquid crystal layer interposed between the substrates, and each pixel region is defined by data lines and gate lines which are formed on the lower substrate so as to cross each other. And a switching element is disposed at an intersection of the lines, and a region of the switching element is provided, wherein the active layer and a source / drain electrode have a predetermined shape. Forming a gate insulating film on the formed lower substrate; (b) forming a gate line and a common bus line spaced parallel to the gate line on the gate insulating layer; (c) forming a lower insulating film on the lower substrate including the gate line and the common bus line, among the first insulating films having an upper red film and a lower insulating film; (d) forming a first transparent electrode on the lower insulating film; (e) forming the upper insulating film on the entire surface of the lower substrate including the first transparent electrode; (f) forming a data line on the upper insulating film; And (g) forming a second insulating film on the lower substrate including the data line, and then forming a second transparent electrode on the second insulating film so as to overlap the first transparent electrode and a predetermined region. The present invention provides a method of manufacturing a liquid crystal display device.

Here, after step (e), a contact hole for electrically connecting the first transparent electrode and the common bus line is formed in a predetermined region on the first transparent electrode and the common bus line to form an upper portion of the contact hole area. It is preferable to further include the step of forming a reflecting plate having a predetermined pattern.

Preferably, the reflective plate may be formed of the same material as a predetermined source / drain metal wire formed to electrically connect the second transparent electrode and the source / drain electrode.

Preferably, the first insulating film may be a silicon oxide film.

Preferably, the second insulating film may be formed using a silicon nitride film.

Preferably, the first insulating film may be formed to have a thickness of 3000 to 4000 kPa.

Preferably, the upper insulating film may be formed to have a thickness of 100 to 1000 kPa.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the following embodiments of the present invention may be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. The embodiments of the present invention are provided to enable those skilled in the art to more fully understand the present invention.

The liquid crystal display according to the exemplary embodiment of the present invention includes a lower substrate, an upper substrate, and a liquid crystal layer interposed between the lower substrate and the upper substrate, and the lower substrate is intersected to apply a voltage to the liquid crystal layer. Each pixel region is defined by the electrodes formed. 2 is a plan view of a pixel area formed on a lower substrate of a liquid crystal display according to an exemplary embodiment of the present invention. 3A to 3C are cross-sectional views taken along the lines II ′, II-II ′, and III-III ′ of FIG. 2, respectively.

On the other hand, the liquid crystal display device according to an embodiment of the present invention has been described as an example of the F-SF mode polycrystalline liquid crystal display device as an example, but is not limited thereto, the type of the liquid crystal display device is not particularly limited as long as the present invention can be applied Do not.

2 to 3C, the liquid crystal display according to the exemplary embodiment of the present invention is arranged such that the gate line 210 and the data line 220 cross on the lower substrate 200 and the gate line 210. A thin film transistor (TFT) T, which is a switching element, is disposed at the intersection of the data line and the first transparent electrode 230 in the unit pixel region defined by the gate line 210 and the data line 220. And the second transparent electrode 240 are disposed, respectively.

Here, the first and second transparent electrodes 230 and 240 may be, for example, common electrodes and pixel electrodes, but are not limited thereto.

In this case, the first transparent electrode 230 overlaps the second transparent electrode 240 by a predetermined region, and the auxiliary capacitance (that is, through the upper insulating film 256 and the second insulating film 260 of the first insulating film 250 to be described later). Storage capacitance) is formed.

In the region where the thin film transistor T is formed, the active layer P and the source / drain electrode 270 patterned in a predetermined shape are provided. The drain electrode of the source / drain electrode 270 is electrically connected to the second transparent electrode 240. Here, the active layer P may be formed using, for example, polysilicon (p-Si) or low temperature polysilicon (LTPS).

A gate insulating layer 280 is formed between the active layer P and the gate line 210, and a common bus line 290 is arranged in parallel with the gate line 210 at a pixel edge portion spaced apart from the gate line 210. do.

The common bus line 290 is formed on the same layer as the gate line 210 and is electrically connected to the first transparent electrode 230 to continuously apply a common signal to the first transparent electrode 230.

A first insulating film 250 is formed on the gate line 210, and the first insulating film 250 includes an upper insulating film 256 and a lower insulating film 255, and the upper insulating film 256 and the lower insulating film ( The first transparent electrode 230 is formed between the 255, and the data line 220 is formed on the upper insulating layer 256, that is, on the first insulating layer 250.

That is, the first transparent electrode 230 is formed in a predetermined region above the lower insulating film 255, and the upper insulating film 256 is deposited on the lower insulating film 255 including the first transparent electrode 230.

Here, the first insulating film 250 is not limited thereto, and three or more insulating films may be included.

Subsequently, a data line 220 is formed in a predetermined region on the first insulating layer 250, and a second insulating layer 260 is formed on the lower substrate 200 including the data line 220, and a second transparent layer is formed thereon. The electrode 240 is formed.

Here, the first insulating film 250 is typically formed of a silicon oxide film-based material such as SiO ₂ or SiON, and the second insulating film 260 is formed of a silicon nitride film-based material such as SiNx. do.

In this case, since the dielectric constant of the silicon oxide based material is smaller than the dielectric constant (about 6.0 to 7.0) of the silicon nitride based material, if the insulating film is formed of the silicon oxide based material, the insulating film is formed on the insulating film as compared with the case of forming the insulating film using only the silicon nitride based material. This makes it difficult to form a subcapacity.

Accordingly, in the liquid crystal display according to the exemplary embodiment, the first insulating layer 250 is formed by dividing the first insulating layer 250 into two different insulating layers, for example, the upper insulating layer 256 and the lower insulating layer 255. Since the thickness of the upper insulating film 256 formed between the 230 and the second transparent electrode 240 can be easily adjusted, the auxiliary capacitance of the upper insulating film 256 and the second insulating film can be effectively formed. .

That is, by minimizing the thickness of, for example, the upper insulating film 260 of the first insulating film 250 formed of the silicon oxide film-based material having a lower dielectric constant than that of the silicon nitride film-based material, the auxiliary capacitance may be effectively formed.

For example, the first insulating film 250 can appropriately adjust the thickness of the upper insulating film 256 within the range of about 100 to 1000 kPa.

In this case, it is preferable that the total thickness of the first insulating film 250 is in a range of about 3000 to 4000 kPa. For example, when the thickness of the first insulating film 250 becomes thinner than the thickness, the screen due to the increase of parasitic capacitance This is because it may cause deterioration of quality.

Meanwhile, referring to FIGS. 2 and 3C, for example, a predetermined region above the second and third contact holes C2 and C3 formed to electrically connect the common bus line 290 and the first transparent electrode 230. The reflection plate R of a predetermined shape may be further provided.

Here, the second and third contact holes C2 and C3 for connecting the common bus line 290 and the first transparent electrode 230, for example, interconnect the active layer P and the source / drain electrodes 270. It is possible to be formed at the same time as the first contact hole (C1) necessary to make.

In this case, the reflective plate R may be formed of the same material on the same layer as the source / drain metal wiring L having a predetermined shape formed to electrically connect the source / drain electrode 270 and the second transparent electrode 240. have.

In addition, the reflective plate R is, for example, a predetermined pattern for causing diffuse reflection on the shapes of the second and third contact holes C2 and C3 formed to connect the common bus line 290 and the first transparent electrode 230. That is, by using the embossing pattern, it is also possible to maximize the internal reflection efficiency by the embossing pattern.

At this time, for example, it is preferable that the black matrix is removed from the color filter area of the upper substrate (not shown) positioned above the diffuse reflection area.

Hereinafter, a manufacturing method of the liquid crystal display device of the present invention will be described with reference to FIGS. 2 and 3A to 3C.

2 to 3B, first, the active layer P is formed on the lower substrate 200 on which the buffer layer B is formed in a predetermined pattern.

Here, the buffer layer B serves to prevent, for example, contamination by the lower substrate 200 in the process of forming the active layer P, and the buffer layer B may be omitted if necessary.

Thereafter, the gate insulating layer 280 is deposited on the lower substrate 200 including the active layer P. In addition, the gate line 210 is formed in a predetermined region on the gate insulating layer 280, and the common bus line 290 is formed on the same layer as the gate line 210.

Thereafter, the first insulating layer 250 is deposited on the lower substrate 200 on which the gate line 210 and the common bus line 290 are formed.

In this case, the first insulating film 250 may be formed by sequentially stacking the upper insulating film 256 and the lower insulating film 255, which are divided into two layers, for example, but are not limited thereto. It is also possible to form by laminating sequentially.

A predetermined region between the upper insulating film 256 and the lower insulating film 255 formed as described above is formed through the first transparent electrode 230.

That is, by forming the first transparent electrode 230 in a predetermined region on the upper surface of the lower insulating film 255, and then depositing the upper insulating film 256 on the lower substrate 200 including the first transparent electrode 230. The first transparent electrode 230 may be formed between the upper insulating film 256 and the lower insulating film 255.

Here, the first insulating film 250 is typically formed of a silicon oxide film-based material such as SiO ₂ or SiON, the thickness of the upper insulating film 256 of the first insulating film 250 is in the range of about 100 to 1000 Å The thickness of the lower insulating film 255 is preferably in the range of about 2000 to 3000 Pa.

Thereafter, after forming the first contact hole C1 to expose a portion of the active layer P, the source / drain electrode 270 electrically connected to the active layer P through the first contact hole C1. And data lines 220 are formed, and a second insulating layer 260 is deposited on the lower substrate 200 including the source / drain electrodes 270 and the data lines 220. In this case, the second insulating layer 260 may be formed of a silicon nitride layer based on, for example, a material such as SiNx.

Next, after forming the fourth contact hole C4 so that a portion of the source-drain electrode 270 is exposed, the second transparent electrode 240 having a slit shape is formed, and the fourth contact hole C4 is formed. The source-drain electrode 270 and the second transparent electrode 240 are electrically connected to each other.

2 and 3C, the reflective plate R may be further formed on the first insulating layer 250.

The reflective plate R is preferably formed in the next step of the process of forming the first insulating layer 250. The reflective plate R may include second and second electrodes for electrically connecting the common bus line 290 and the first transparent electrode 240 to each other. After forming the third contact holes C2 and C3, the method may further include forming a predetermined metal wire in an upper region of the contact holes C2 and C3.

The second and third contact holes C2 and C3 for connecting the common bus line 290 and the first transparent electrode 230 may be formed at the same time as the first contact hole C1.

In addition, the metal line for forming the reflector plate R is formed on the same layer as a predetermined source / drain metal line L formed to electrically connect the source / drain electrode 270 and the second transparent electrode 240. It is possible to form using the same material.

In addition, the reflective plate R is, for example, predetermined to cause diffuse reflection of the shapes of the second and third contact holes C2 and C3 formed to connect the common bus line 290 and the first transparent electrode 230. By using it as a pattern, that is, an embossing pattern, it is also possible to maximize the internal reflection efficiency by the embossing pattern.

Although a preferred embodiment of the above-described liquid crystal display and a method for manufacturing the same according to the present invention have been described, the present invention is not limited thereto, and various modifications are made within the scope of the claims and the detailed description of the invention and the accompanying drawings. It is possible to carry out by this and this also belongs to the present invention.

1 (a) and 1 (b) are cross-sectional views for explaining a conventional liquid crystal display device.

2 is a plan view of a pixel area formed on a lower substrate of a liquid crystal display according to an exemplary embodiment of the present invention.

3A to 3C are cross-sectional views taken along the lines II ′, II-II ′, and III-III ′ of FIG. 2, respectively.

Claims (14)

A lower substrate, an upper substrate, and a liquid crystal layer interposed between the substrates, and each pixel region is defined by a plurality of data lines and gate lines formed on the lower substrate by crossing each other. In the liquid crystal display device having a switching element is disposed in the intersection region of the, and the switching element is disposed in the active layer and the source and drain electrodes of a certain form, First and second transparent electrodes included in the pixel area and spaced apart from each other to overlap a predetermined area in order to control an amount of light transmission by applying an electric field to the liquid crystal layer; A first insulating film interposed between the data line and the gate line; And A second insulating film interposed between the data line and the second transparent electrode, The first insulating layer may include an upper insulating layer and a lower insulating layer, and the first transparent electrode may be formed between the upper insulating layer and the lower insulating layer, and may be spaced apart from the gate line on the same layer as the gate line. And a reflecting plate having a predetermined pattern is formed on the contact hole region formed to electrically connect the common bus line and the first transparent electrode. delete The method according to claim 1, And the reflective plate is formed of the same material as a predetermined source and drain metal wire formed to electrically connect the second transparent electrode and the source and drain electrodes. The method according to claim 1, The material for forming the first insulating film is a silicon oxide film. The method according to claim 1, The material for forming the second insulating film is a silicon nitride film. The method according to claim 1, And the first insulating film has a thickness of 3000 to 4000 GPa. The method according to claim 1, And the upper insulating film has a thickness of 100 to 1000 GPa. Each pixel region is defined by a data line and a gate line, which include a lower substrate, an upper substrate, and a liquid crystal layer interposed between the substrates, and the lower substrate is formed to intersect with each other. In the method of manufacturing a liquid crystal display device having an element is disposed, the active element and the source and drain electrodes of a certain form is provided in the region where the switching element is disposed, (a) forming a gate insulating film on the lower substrate on which the active layer is formed; (b) forming a gate line and a common bus line spaced parallel to the gate line on the gate insulating layer; (c) forming a lower insulating film on the lower substrate including the gate line and the common bus line, among the first insulating films having an upper insulating film and a lower insulating film; (d) forming a first transparent electrode on the lower insulating film; (e) forming the upper insulating film on the entire surface of the lower substrate including the first transparent electrode; (f) forming a data line on the upper insulating film; And (g) forming a second insulating layer on the lower substrate including the data line, and then forming a second transparent electrode on the upper portion of the second insulating layer to overlap the first transparent electrode and a predetermined region, After the step (e), a contact hole for electrically connecting the first transparent electrode and the common bus line is formed in a predetermined region on the first transparent electrode and the common bus line to be formed on the contact hole region. Forming a reflective plate having a pattern further comprising the step of manufacturing a liquid crystal display device. delete The method of claim 8, And the reflecting plate is formed of the same material as a predetermined source and drain metal wiring formed to electrically connect the second transparent electrode and the source and drain electrodes. The method of claim 8, And the first insulating film is formed by using a silicon oxide film. The method of claim 8, And the second insulating film is formed by using a silicon nitride film. The method of claim 8, And the first insulating film is formed to have a thickness of 3000 to 4000 GPa. The method of claim 8, And the upper insulating film is formed to have a thickness of about 100 to about 1000 GPa.

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