KR20030050983A - Liquid Crystal Display Device and Fabricating Method Thereof - Google Patents

Abstract

PURPOSE: A liquid crystal display and a method for fabricating the liquid crystal display are provided to form a storage electrode using an organic conductive material to improve aperture rate. CONSTITUTION: A liquid crystal display includes a gate line(32) formed on a substrate(31), a gate insulating layer(42) formed on the gate line, and a storage electrode(54) formed of a transparent organic conductive material on the gate insulating layer. The liquid crystal display further includes a passivation layer(48) that is formed on the storage electrode and gate insulating layer and has a contact hole(56), and a pixel electrode(52) formed on the passivation layer and electrically connected to the storage electrode through the contact hole.

Description

Liquid crystal display device and its manufacturing method {Liquid Crystal Display Device and Fabricating Method Thereof}

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device and a method of manufacturing the same that can increase the aperture ratio.

Conventional liquid crystal display devices display an image by adjusting the light transmittance of the liquid crystal using an electric field. To this end, the liquid crystal display device includes a liquid crystal panel in which liquid crystal cells are arranged in a matrix, and a driving circuit for driving the liquid crystal panel. The liquid crystal panel is provided with pixel electrodes and a common electrode for applying an electric field to each of the liquid crystal cells. In general, the pixel electrode is formed for each liquid crystal cell on the lower substrate, while the common electrode is integrally formed on the front surface of the upper substrate. Each of the pixel electrodes is connected to a thin film transistor (hereinafter referred to as "TFT") used as a switch element. The pixel electrode drives the liquid crystal cell together with the common electrode according to the data signal supplied through the TFT.

1 and 2, the lower substrate 1 of the liquid crystal display device includes a TFT part TP positioned at an intersection of the data line 4 and the gate line 2, and a drain electrode of the TFT TP. A pixel electrode 22 connected to the pixel 10 and a storage capacitor part SP positioned at an overlapping portion of the pixel electrode 22 and the gate line 2 are provided.

The TFT portion TP is connected to the pixel electrode 22 through the gate electrode 6 connected to the gate line 2, the source electrode 8 connected to the data line 4, and the drain contact hole 20. The drain electrode 10 is formed. The TFT portion TP further includes semiconductor layers 14 and 16 for forming a channel between the source electrode 8 and the drain electrode 10 by the gate voltage supplied to the gate electrode 6. The TFT portion TP selectively supplies the data signal from the data line 4 to the pixel electrode 22 in response to the gate signal from the gate line 2.

The pixel electrode 22 is formed in a cell region divided by the data line 4 and the gate line 2 and is made of a transparent inorganic electroconductive material having high light transmittance. The pixel electrode 22 generates a potential difference from a common electrode (not shown) formed on an upper substrate (not shown) by a data signal supplied through the drain contact hole 20. Due to this potential difference, the liquid crystal located between the lower substrate 1 and the upper substrate (not shown) is rotated by the dielectric anisotropy. Accordingly, the light supplied from the light source via the pixel electrode 22 is transmitted to the upper substrate.

The storage capacitor part SP plays a role of suppressing a voltage variation of the pixel electrode 22. The storage capacitor part SP is formed of the storage electrode 24 with the gate line 2 and the gate insulating layer 12 interposed therebetween. The storage electrode 24 is electrically connected to the pixel electrode 22 through the storage contact hole 26 formed on the passivation layer 18.

The method of manufacturing the liquid crystal display device will be described with reference to FIGS. 3A to 3E.

First, the gate line 2 and the gate electrode 6 are formed by depositing a gate metal layer on the lower substrate 1 and then patterning the same, as shown in FIG. 3A. The gate insulating layer 12 is formed by depositing a first insulating material on the lower substrate 1 on which the gate line 2 and the gate electrode 6 are formed. By depositing and patterning the first and second semiconductor materials on the gate insulating film 12, the active layer 14 and the ohmic contact layer 16 are formed as shown in FIG. 3B. Then, by depositing and patterning the data metal layer on the gate insulating film 12, the storage electrode 24, the source electrode 8 and the drain electrode 10, as shown in Figure 3c is formed. Thereafter, after the second insulating material is deposited to form the protective layer 18 as illustrated in FIG. 3D, the drain contact hole 20 and the storage contact hole 26 penetrating the protective layer 18 are formed. . The pixel electrode 22 is formed as shown in FIG. 3E by depositing and patterning an inorganic transparent conductive material on the lower substrate 1 on which the protective layer 18 is formed.

As the liquid crystal display device increases in size, the storage capacitor value Cst for stably maintaining the pixel voltage should increase. However, when the area of the storage electrode 24 is increased in proportion to the storage capacitor value Cst to increase the storage capacitor value Cst, the overlapping area of the pixel electrode 22 and the storage electrode 24 becomes wider to the display area. All. Since the light is not transmitted through the overlapping area H between the display area and the storage electrode 24 by the storage electrode 24 formed of metal up to the display area, there is a problem that the aperture ratio decreases.

To solve this problem, the storage electrode 24 is formed of ITO, TZO, ITZO, or the like, which is the same transparent inorganic material as the pixel electrode 22. However, there is a problem in that expensive vacuum equipment such as a sputter is required to deposit an inorganic transparent inorganic electroconductive material on the gate insulating layer 12.

Accordingly, it is an object of the present invention to provide a liquid crystal display device and a method of manufacturing the same which can increase the aperture ratio.

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

FIG. 2 is a cross-sectional view of the liquid crystal display taken along the line "A-A '" in FIG.

3A through 3E are cross-sectional views illustrating a method of manufacturing the liquid crystal display device illustrated in FIG. 2.

4 is a plan view showing a liquid crystal display device according to the present invention.

FIG. 5 is a cross-sectional view illustrating a liquid crystal display taken along the line “B-B ′” in FIG. 4.

FIG. 6 is a view illustrating a material for forming the storage electrode illustrated in FIG. 6.

7A to 7E are cross-sectional views illustrating a method of manufacturing the liquid crystal display shown in FIG. 5 in stages.

<Explanation of symbols for the main parts of the drawings>

1,31: Lower substrate 2,32: Gate line

4,34 data line 6,36 gate electrode

8,38 source electrode 10,40 drain electrode

12,42 gate insulating film 14,44 active layer

16,46: ohmic contact layer 18,48: protective layer

20, 26, 50, 56: contact hole 22, 52: pixel electrode

In order to achieve the above objects, the liquid crystal display device according to the present invention comprises a gate line formed on a substrate, a gate insulating film formed on the gate line, a storage electrode formed of a transparent organic conductive material on the gate insulating film, and storage A protective layer formed on the electrode and the gate insulating film, and a pixel electrode formed in contact with the storage electrode by forming a contact hole on the protective layer.

The transparent organic conductive material is polyethylene dioxythiophene (Poly (3,4-ethylenedioxythiophene), polyacetylene (Polyacetylene), polypyrrole (Polypyrrole), polythiophene, polyphenylene sulfide (Polyphenylene sulfide), polypheny Among polyphenylene vinylene, polyazulene, polyphenylene, polyaniline, polyfuran, polyisothianaphthene and polythienylene vinylene It is characterized by at least one.

The liquid crystal display device further includes a gate electrode connected to the gate line, and a source and a drain electrode formed of the same material as the storage electrode.

In order to achieve the above object, a method of manufacturing a liquid crystal display device according to the present invention comprises the steps of forming a gate line on a substrate, forming a gate insulating film on the substrate, spin the transparent organic electroconductive material on the gate insulating film Depositing and patterning the coating to form a storage electrode, depositing and patterning a protective layer to cover the storage electrode to form a contact hole, and electrically connected to the storage electrode through the contact hole on the protective layer. Forming a pixel electrode.

The manufacturing method of the liquid crystal display device includes forming a gate electrode connected to a gate line on a substrate, forming a semiconductor layer on the gate insulating layer, and forming a source and a drain electrode from the same material as the storage electrode. Characterized in that it comprises a.

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

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 4 to 7E.

4 and 5, the lower substrate 31 of the liquid crystal display device includes a TFT part TP positioned at an intersection of the data line 34 and the gate line 32, and a drain of the TFT part TP. A pixel electrode 52 connected to the electrode 40 and a storage capacitor part SP positioned at an overlapping portion with the pixel electrode 52 and the gate line 32 of the previous stage are provided.

The TFT portion TP is connected to the pixel electrode 52 through the gate electrode 36 connected to the gate line 32, the source electrode 38 connected to the data line 34, and the drain contact hole 50. The drain electrode 40 is formed. The TFT portion TP further includes semiconductor layers 44 and 46 for forming a channel between the source electrode 38 and the drain electrode 40 by the gate voltage supplied to the gate electrode 36. The TFT portion TP selectively supplies the data signal from the data line 34 to the pixel electrode 52 in response to the gate signal from the gate line 32.

The pixel electrode 52 is formed in a cell region divided by the data line 34 and the gate line 32 and is made of a transparent inorganic electroconductive material having high light transmittance. The pixel electrode 52 generates a potential difference from a common electrode (not shown) formed on the upper substrate (not shown) by the data signal supplied through the drain contact hole 50. Due to this potential difference, the liquid crystal located between the lower substrate 31 and the upper substrate (not shown) is rotated by the dielectric anisotropy. Accordingly, the light supplied from the light source via the pixel electrode 52 is transmitted to the upper substrate.

The storage capacitor part SP plays a role of suppressing a voltage variation of the pixel electrode 52. The storage capacitor part SP includes a storage electrode 54 formed to overlap the gate line 32 with the gate line 32 and the gate insulating layer 42 therebetween. The storage electrode 54 is in electrical contact with the pixel electrode 52 through the storage contact hole 56 formed in the passivation layer 48. The storage electrode 54 is formed of a transparent organic electroconductive material shown in FIG. Preferably, it is formed of poly (3,4-ethylenedioxythiophene).

The transparent organic electroconductive material is formed by depositing a pattern on the gate insulating film 42 by spin coating. Accordingly, expensive vacuum equipment is unnecessary. In addition, since the story electrode is formed of a transparent organic conductive material in the overlapping region of the display region where the light does not pass through and the storage electrode 54, light may be transmitted to increase the aperture ratio.

7A to 7E are cross-sectional views sequentially illustrating a method of manufacturing the liquid crystal display device illustrated in FIG. 5.

Referring to FIG. 7A, a gate metal layer is deposited on the lower substrate 31 by a deposition method such as sputtering. Aluminum (Al), copper (Cu), or the like is formed as the gate metal layer. Subsequently, the gate line 32 and the gate electrode 36 are formed by patterning the gate metal layer by a photolithography process including an etching process.

Referring to FIG. 7B, a gate insulating layer 42 is formed on the substrate 31 on which the gate line 32 and the gate electrode 36 are formed. The gate insulating layer 42 is formed of an inorganic insulating material, silicon oxide (SiOx) or silicon nitride (SiNx). First and second semiconductor layers are successively deposited on the gate insulating layer 42 by a chemical vapor deposition method. The first semiconductor layer is formed of amorphous silicon that is not doped with impurities, and the second semiconductor layer is formed of amorphous silicon that is doped with N-type or P-type impurities. Subsequently, the first and second semiconductor layers are patterned by a photolithography method including a dry etching process to form an active layer 44 and an ohmic contact layer 46.

Referring to FIG. 7C, a data metal layer is deposited by spin coating on the gate insulating layer 32 on which the active layer 44 and the ohmic contact layer 46 are formed. The data metal layer is made of a transparent organic electroconductive material shown in FIG. Subsequently, the data metal layer is patterned by a photolithography process including an etching process to form the storage electrode 54, the source electrode 38, and the drain electrode 40. Next, the ohmic contact layer 46 exposed between the source electrode 38 and the drain electrode 40 is removed by a dry etching process to separate the source electrode 38 and the drain electrode 40. By partially removing the ohmic contact layer 46, the portion of the active layer 44 corresponding to the gate electrode 36 between the source and drain electrodes 38 and 40 becomes a channel.

Referring to FIG. 7D, a passivation layer 48 is formed on the substrate 31 on which the storage electrodes 54, the source and drain electrodes 38 and 40 are formed. As the material of the protective film 48, an organic insulating material such as an acryl-based organic compound, a benzocyclobutene (BCB), a perfluorocyclobutane (PFCB), or an inorganic insulating material such as silicon nitride (SiNx) or silicon oxide (SiOx) may be used. do. The protective layer 48 is patterned by a photolithography process including a dry etching process to form a drain contact hole 50 exposing the drain electrode 40 and a storage contact hole 56 exposing the storage electrode 54. .

Referring to FIG. 7E, the transparent electrode layer is formed on the passivation layer 48 by a deposition method such as sputtering. The material of the transparent electrode layer is Indium-Tin-Oxide (ITO), Indium-Zinc-Oxide (IZO) or Indium-Tin-Zinc- Oxide: ITZO). Subsequently, the pixel electrode 52 is formed by patterning the transparent electrode layer by a photolithography process including an etching process. The pixel electrode 52 is connected to the drain electrode 40 through the drain contact hole 50 formed on the passivation layer 48, and is connected to the storage electrode 54 through the storage contact hole 56.

As described above, the liquid crystal display device and the method of manufacturing the same according to the present invention form a storage electrode with an organic conductive material. Since light is transmitted from the pixel electrode overlapping the storage electrode formed of the organic conductive material, the opening area is widened to the overlapping area, thereby increasing the aperture ratio. In addition, by depositing an organic conductive material which is a material of the storage electrode by spin coating, conventional expensive vacuum equipment is unnecessary.

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 (6)

A gate line formed on the substrate, A gate insulating film formed on the gate line; A storage electrode formed of a transparent organic conductive material on the gate insulating layer; A protective layer formed on the storage electrode and the gate insulating layer; And a pixel electrode formed in contact with the storage electrode by forming a contact hole in the protective layer. The method of claim 1, The transparent organic conductive material is polyethylene dioxythiophene (Poly (3,4-ethylenedioxythiophene), polyacetylene (Polyacetylene), polypyrrole (Polypyrrole), polythiophene, polyphenylene sulfide (Polyphenylene sulfide), polypheny Among polyphenylene vinylene, polyazulene, polyphenylene, polyaniline, polyfuran, polyisothianaphthene and polythienylene vinylene At least one liquid crystal display device characterized in that. The method of claim 1, A gate electrode connected to the gate line; And a source and a drain electrode formed of the same material as the storage electrode. Forming a gate line on the substrate; Forming a gate insulating film on the substrate; Depositing a transparent organic electroconductive material on the gate insulating layer by spin coating and patterning to form a storage electrode; Depositing and patterning a protective layer to cover the storage electrode to form a contact hole; And forming a pixel electrode electrically connected to the storage electrode through the contact hole on the protective layer. The method of claim 4, wherein The transparent organic conductive material is polyethylene dioxythiophene (Poly (3,4-ethylenedioxythiophene), polyacetylene (Polyacetylene), polypyrrole (Polypyrrole), polythiophene, polyphenylene sulfide (Polyphenylene sulfide), polypheny At least of polyphenylene vinylene, polyazulene, polyphenylene, polyaniline, polyfuran, polyisothianaphthene and polythienylenevinylene A method for manufacturing a liquid crystal display device, characterized in that any one. The method of claim 4, wherein Forming a gate electrode connected to the gate line on the substrate; Forming a semiconductor layer on the gate insulating film; And forming a source and a drain electrode from the same material as the storage electrode.