KR20080062114A - Thin film transistor substrate in liquid crystal display device and method of manufacturing the same - Google Patents

Abstract

A TFT(Thin Film Transistor) array substrate for an LCD(Liquid Crystal Display) and a method of manufacturing the TFT array substrate are provided to use a transparent carbon layer pattern as a passivation layer to reduce parasitic capacitance to thereby prevent signal distortion. A TFT array substrate includes gate lines arranged in parallel on an insulating substrate(104), a gate insulating layer(24) covering the gate lines, and first and second semiconductor patterns(26,28) formed on the gate insulating layer. The TFT array substrate further includes data lines intersecting the gate lines to define pixel regions, a source electrode(32), a drain electrode(34), a transparent carbon layer pattern(42), and a pixel electrode(54). The transparent carbon layer pattern has a contact hole(46) which exposes the drain electrode. The pixel electrode is formed on the transparent carbon layer pattern and electrically connected to the drain electrode through the contact hole.

Description

Thin film transistor substrate for liquid crystal display device and manufacturing method therefor {THIN FILM TRANSISTOR SUBSTRATE IN LIQUID CRYSTAL DISPLAY DEVICE AND METHOD OF MANUFACTURING THE SAME}

1 is a plan view illustrating a thin film transistor substrate for a liquid crystal display according to an exemplary embodiment of the present invention.

2A through 2D are cross-sectional views illustrating a step in manufacturing a thin film transistor substrate for a liquid crystal display according to an exemplary embodiment of the present invention.

3 is a cross-sectional view illustrating an ion plating apparatus for forming the transparent carbon film pattern shown in FIG. 2C.

The present invention relates to a thin film transistor substrate for a liquid crystal display device and a manufacturing method thereof, and more particularly, to a thin film transistor substrate for a liquid crystal display device having a transparent carbon film having a low dielectric constant as a protective film and a method for manufacturing the same.

In recent years, information processing apparatuses for processing massive data and display apparatuses for displaying data processed by the information processing apparatuses as images have been developed.

Examples of typical display devices include liquid crystal displays, organic light generating devices, plasma display panels, and the like.

The liquid crystal display device displays an image using liquid crystals, the organic light generating device displays an image using an organic light emitting layer, and the plasma display panel displays an image using plasma.

The liquid crystal display is one of the most widely used flat panel display devices. The liquid crystal display includes two glass substrates on which electrodes are formed and a liquid crystal layer interposed therebetween. A display device that controls the amount of light transmitted by rearranging molecules.

A thin film transistor for switching a voltage applied to an electrode is formed on one substrate of the liquid crystal display. In addition to the thin film transistor, the thin film transistor includes a pixel electrode connected to the thin film transistor, a gate line to which a gate signal is applied, and a data signal. An applied data line is formed.

Here, when the data line and the pixel electrode overlap, they form a parasitic capacitance with an insulating film interposed therebetween, so that a signal distortion occurs, so that the data line and the pixel electrode do not overlap. However, in this case, the aperture ratio is reduced because the size of the pixel electrode is reduced.

An object of the present invention is to reduce the parasitic capacitance and improve the aperture ratio of a thin film transistor substrate for a liquid crystal display device.

Another object of the present invention is to provide a method of manufacturing the thin film transistor substrate for a liquid crystal display device.

In order to achieve this problem, in the present invention, the protective film is formed of a transparent carbon film such as diamond-like-carbon (DLC) having a low dielectric constant.

The thin film transistor substrate for a liquid crystal display according to the above object includes a gate wiring including a plurality of gate lines parallel to each other on an insulating substrate, a gate insulating film covering the gate wiring, a first semiconductor pattern and a second semiconductor on the gate insulating film. And a data line including a pattern, and a plurality of data lines, a source electrode, and a drain electrode, which vertically intersect the gate line to define a plurality of pixel regions. The display device may further include a transparent carbon film pattern including a contact hole exposing the drain electrode on the data line, and a pixel electrode electrically connected to the drain electrode through the contact hole on the transparent carbon film pattern.

According to another aspect of the present invention, there is provided a method of fabricating a thin film transistor substrate for a liquid crystal display device, forming a gate wiring including a plurality of gate lines, forming a gate insulating film covering the gate wiring, and forming a first insulating film on the gate insulating film. A data line including a semiconductor pattern and a second semiconductor pattern, and a plurality of data lines, a source electrode, and a drain electrode, which vertically intersect the gate line and define a plurality of pixel regions, is formed. A transparent carbon film pattern including a first contact hole exposing the drain electrode is formed on the data line, and a pixel electrode electrically connected to the drain electrode through the first contact hole is formed on the transparent carbon film pattern.

Hereinafter, a thin film transistor substrate for a liquid crystal display and a method of manufacturing the same according to embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited to the following embodiments. Those skilled in the art will be able to implement the present invention in various other forms without departing from the spirit of the present invention.

Thin film transistor substrate for liquid crystal display

1 is a plan view illustrating a thin film transistor substrate for a liquid crystal display according to an exemplary embodiment of the present invention. FIG. 2D is a cross-sectional view taken along the line II ′ of FIG. 1.

1 and 2D, aluminum (Al) or aluminum alloy (Mo alloy), molybdenum (Mo), or molybdenum-tungsten alloy (MoW), chromium (Cr), and tantalum (Ta) are disposed on the insulating substrate 104. A gate wiring made of a metal such as copper (Cu) or a conductor is formed. The gate wiring is connected to the gate line GL extending in the horizontal direction, the gate electrode 20 that is part of the gate line GL, and the end of the gate line GL, and receives a scan signal from the outside to transfer the gate signal to the gate line GL. And a gate pad GP. However, in some cases, unlike the embodiment of the present invention, the scan signal may be directly applied to the gate line GL on the substrate without a gate pad.

The gate line including the gate line GL and the gate pat GP may be formed as a single layer, but may be formed as a double layer or a triple layer. In the case of forming more than two layers, it is preferable that one layer is made of a material having a low resistance and the other layer is made of a material having good contact properties with other materials, for example, a double layer of Cr / Al (or Al alloy) or Al Bilayers of / Mo. In addition, the storage electrode 36 formed of the same material as the gate wiring is formed on the insulating substrate 104.

A gate insulating layer 24 made of an insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx) is formed on the gate wiring.

A first semiconductor pattern 26 made of a semiconductor such as amorphous silicon is formed on the gate insulating layer 24, and an amorphous silicon doped with n-type impurities such as phosphorus (P) is formed on the first semiconductor pattern 26. The second semiconductor pattern 28 made of a semiconductor is separated from both sides with respect to the gate electrode 20. In the present embodiment, the first semiconductor pattern 26 and the second semiconductor pattern 28 form a semiconductor pattern 30.

On the second semiconductor pattern 28, a data line made of a metal or a conductor such as aluminum or an aluminum alloy, molybdenum or molybdenum-tungsten alloy, chromium, tantalum, or copper is formed. The data line includes a data line DL extending in the vertical direction, a source electrode 32 which is a part of the data line DL, a drain electrode 34 corresponding to the source electrode 32 around the gate electrode 20, And a data pad DP connected to the data line DL to receive an image signal from the outside and to transfer the image signal to the data line DL, and may further include a storage electrode 36.

Here, the edges of the first semiconductor pattern 26 and the second semiconductor pattern 28, and the source electrode 32 and the drain electrode 34 may be formed on the same line. However, in some cases, unlike the embodiment of the present invention, the edges of the first semiconductor pattern 26 and the second semiconductor pattern 28 and the source electrode 32 and the drain electrode 34 are on different lines. It may be formed.

On the other hand, the data wirings can be formed in a single layer like the gate wirings, but can also be formed in a double layer or a triple layer. In the case of forming more than two layers, it is preferable that one layer is formed of a material having a low resistance and the other layer is formed of a material having good contact properties with other materials.

The transparent carbon film pattern 42 is formed on the data line and the gate insulating film 24.

The transparent carbon film pattern 42 generally has a lower dielectric constant than that of the nitride film SiNx having a dielectric constant of about 3.9. In this embodiment, the dielectric constant of the transparent carbon film pattern 42 is about 2 to about 3.5. Examples of the material that can be used as the transparent carbon film pattern 42 include diamond-like-carbon (DLC) containing fluorine (F).

In addition, the transparent carbon film pattern 42 contains fluorine (F) at about 0.01% wt to about 0.5% wt. As the transparent carbon film pattern 42 includes a trace amount of fluorine, the transparent carbon film pattern 42 has a visible light transmittance of about 85% to about 95%.

In addition, the transparent carbon film pattern 42 may be formed to a thickness of about 1 ㎛ to about 4 ㎛.

Meanwhile, the transparent carbon film pattern 42 not only has a first contact hole 44 exposing the lower gate pad 22 together with the gate insulating film 24, but also the lower data pad 38 of the data pad DP. Has a second contact hole 50 exposing a and a third contact hole 46 exposing a drain electrode 34. In addition, the transparent carbon layer pattern 42 may further include a fourth contact hole 48 exposing the storage electrode 36.

The pixel electrode 54, the auxiliary gate pad 52, and the auxiliary data pad 56 made of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), or a-ITO are disposed on the transparent carbon layer pattern 42. ) Is formed.

The pixel electrode 54 is connected to the drain electrode 34 through the third contact hole 46 to receive an image signal, and overlaps the data line DL. The auxiliary gate pad 52 and the auxiliary data pad 56 are connected to the lower gate pad 22 and the lower data pad 38 through the first and second contact holes 44 and 50, respectively. The adhesion between the gate pad 22 and the lower data pad 38 and the external circuit device may be compensated, and the lower gate pad 22 and the lower data pad 38 may be protected. In addition, the pixel electrode 54 may be connected to the storage electrode 36 overlapping the front gate line through the fourth contact hole 48.

Here, since the transparent carbon film pattern 42 is formed of a material having a low dielectric constant, the parasitic capacitance is small even when the data line DL and the pixel electrode 54 are overlapped, thereby reducing problems due to signal interference.

Method of manufacturing thin film transistor substrate for liquid crystal display device

2A through 2D are cross-sectional views illustrating a step in manufacturing a thin film transistor substrate for a liquid crystal display according to an exemplary embodiment of the present invention.

First, aluminum (Al) or aluminum alloy (Al alloy), molybdenum (Mo) or molybdenum-tungsten alloy (MoW), chromium (Cr), tantalum (Ta) copper (Cu) on the insulating substrate 104 as shown in FIG. A gate wiring made of a single layer or a double layer or a triple layer of metal or a conductor, such as a metal is formed. The metal layer of the gate wiring is formed on the insulating substrate 104 through a deposition method such as a sputtering method, and the metal layer of the gate wiring is patterned by a photolithography process and an etching process using a first mask. The gate line is connected to a gate line GL extending in the horizontal direction, a gate electrode 20 that is part of the gate line GL, and an end of the gate line 20, and receives a scan signal from the outside to the gate line GL. And a gate pad GP for transferring. However, in some cases, unlike the embodiment of the present invention, the gate pad GP may not be formed. In addition, a storage electrode may be formed on the insulating substrate 104 simultaneously with the gate wiring. Subsequently, the present invention sequentially forms the gate insulating film 24, the first semiconductor pattern 26, the second semiconductor pattern 28, and the data wiring on the insulating substrate 104 on which the gate wiring is formed as shown in FIG. 2B. . The data line may include a data line DP extending in the vertical direction, a source electrode 32 that is part of the data line DP, and a drain electrode corresponding to the source electrode 32 around the gate electrode 20. 34) and a data pad DP connected to the data line 34 to receive an image signal from the outside and transmit the image signal to the data line 34.

When the process is described step by step, the gate insulating film 24, the first semiconductor layer, and the second semiconductor layer are formed on the gate wiring through a deposition method such as PECVD. The metal layer of the data line is sequentially formed by a deposition method such as sputtering.

Insulating materials such as silicon oxide (SiOx) or silicon nitride (SiNx) are selected as the gate insulating film 24, and as the metal layer of the data wiring, aluminum or aluminum alloy, molybdenum or molybdenum-tungsten alloy, chromium, tantalum, copper, or the like. Of metals or conductors may be selected. Next, a photoresist pattern is formed on the metal layer of the data line including the source electrode and the drain electrode by a photolithography process using a second mask.

The second mask uses a diffraction exposure mask or a transflective mask having a diffraction exposure portion in the channel portion of the thin film transistor so that the exposure amount of the photoresist pattern in the channel portion is smaller than that of the photoresist pattern positioned in another portion, and thus, the channel after the stripping process The thickness of the negative photoresist pattern is made low.

The metal layer of the data line is patterned by a wet etching process using a photoresist pattern to form the data line DL, the source electrode 32, and the drain electrode 34. In addition, the storage electrode 36 may be further formed.

Next, the second semiconductor layer and the first semiconductor layer are simultaneously etched by a dry etching process using the same photoresist pattern to form the semiconductor pattern 30 having the second semiconductor pattern 28 and the first semiconductor pattern 26. do.

Thereafter, the photoresist pattern having a relatively low height is removed from the channel portion of the thin film transistor by an ashing process, and then the source electrode 32 and the drain electrode 34 are removed from the channel portion of the thin film transistor by a dry etching process. The metal layer and the second semiconductor layer of the included data line are etched. As a result, the first semiconductor pattern is exposed in the channel portion, and the source electrode 32 and the drain electrode 34 are separated. The photoresist pattern is then removed by a stripping process. The edges of the first semiconductor pattern 26 and the second semiconductor pattern 28, and the source 32 and the drain electrode 34 may be formed on the same line. Meanwhile, unlike the manufacturing process of FIG. 2B, the lower plate manufacturing process of the liquid crystal display according to the exemplary embodiment of the present invention may include a mask process for forming the first semiconductor pattern 26 and the second semiconductor pattern 28, and data. The mask process for forming wiring can be separated.

As shown in FIG. 2C, the transparent carbon film pattern 42 is formed on the data line and the gate insulating film 24. The transparent carbon film for forming the transparent carbon film pattern is formed by an ion plating device 250 illustrated in FIG. 3.

Referring to FIG. 3, in detail, the ion plating apparatus 250 may be disposed in a box shape, and may be spaced apart from the first cathode electrode 252, the first cathode electrode 252 having the top surface opened, and the first cathode electrode 252 being opened. The hydrocarbon-based gas and the fluorine gas between the second cathode electrode 253, the first cathode electrode 252, and between the anode electrode 254, the anode electrode 254, and the cathode electrode 252 disposed adjacent to the opening. It has a gas supply unit 256 for providing a and a permanent magnet 259 having an N pole and an S pole. The S pole of the permanent magnet 259 is connected to the first cathode electrode 252, and the N pole of the permanent magnet 259 is connected to the second cathode electrode 253.

In a state where power is applied to the first and second cathode electrodes 252 and 253 and the anode electrode 254 of the ion plating apparatus 250, the ions are supplied as the hydrocarbon gas and the fluorine gas are supplied from the gas supply unit 256. A transparent carbon material is discharged into an opening between the first cathode electrode 252 and the second cathode electrode 253 of the plating apparatus 250, and the carbon material is formed on the surface of the data line and the gate insulating layer.

The transparent carbon film formed by the ion plating apparatus is patterned by a photolithography process and an etching process using a third mask to form first to third contact holes 44, 50, and 46.

Referring to FIG. 2D, the first contact hole 44 penetrates the transparent carbon film and the gate insulating film 24 to expose the lower gate pad 22, and the second contact hole 50 penetrates the transparent carbon film to lower data. The pad 38 is exposed, and the third contact hole 46 penetrates the transparent carbon film to expose the drain electrode 34 of the thin film transistor. In addition, a fourth contact hole 48 may be further formed through the transparent carbon film to expose the storage electrode.

The pixel electrode 54, the auxiliary gate pad 52, and the auxiliary data pad 56 made of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), or a-ITO are disposed on the transparent carbon layer pattern 42. ).

In detail, the transparent electrode material is deposited on the transparent carbon film pattern 42 by a deposition method such as sputtering. Indium tin oxide (ITO), tin oxide (TO) or indium zinc oxide (Indium Zinc Oxide IZO) is used as the transparent electrode material. Next, according to the present invention, the transparent electrode material is patterned by a photolithography process and an etching process using a fourth mask to form a transparent electrode pattern such as the pixel electrode 46, the auxiliary gate pad 52, and the auxiliary data pad 56. To form. The pixel electrode 46 is connected to the drain electrode 34 of the thin film transistor through the third contact hole 46, and the auxiliary gate pad 52 is connected to the lower gate pad 22 through the first contact hole 44. ), And the auxiliary data pad 56 is connected to the lower data pad 38 through the second contact hole 50. In addition, the pixel electrode 54 may be connected to the storage electrode 36 overlapping the front gate line through the fourth contact hole 48.

As described in detail above, a transparent carbon film pattern having a lower dielectric constant than a nitride film is used as the passivation layer, thereby reducing parasitic capacitance to prevent signal distortion and overlapping the pixel electrode with the data line or the gate line, thereby improving the aperture ratio of the pixel electrode. It has an effect to make.

Although the detailed description of the present invention has been described with reference to the embodiments of the present invention, those skilled in the art or those skilled in the art will have the spirit and scope of the present invention as set forth in the claims below. It will be appreciated that various modifications and variations can be made in the present invention without departing from the scope of the art.

Claims (14)

Insulation board, A gate wiring including a gate line and a gate electrode formed on the substrate; A gate insulating film covering the gate wiring, A semiconductor layer formed on the gate insulating film, A data wiring comprising a data line, a source electrode and a drain electrode, A protective film having a contact hole for exposing the drain electrode, A pixel electrode connected to the drain electrode through the contact hole Including; The protective film is a thin film transistor substrate for a liquid crystal display device, characterized in that the transparent carbon film pattern. The thin film transistor substrate of claim 1, wherein the transparent carbon film pattern is a diamond-like carbon film. The thin film transistor substrate of claim 1, wherein a dielectric constant of the transparent carbon film pattern is 2 to 3.5. The thin film transistor substrate for a liquid crystal display device of claim 1, wherein the transparent carbon film pattern has a thickness of 1 μm to 4 μm. The thin film transistor substrate of claim 1, wherein the transparent carbon film pattern has a transmittance of 85% to 95% of visible light. The thin film transistor substrate of claim 1, wherein the transparent carbon film pattern comprises 0.01% to 0.5% wt of fluorine. The thin film transistor substrate of claim 1, wherein the pixel electrode and a portion of the data line or the gate line overlap each other. Forming a gate line and a gate electrode on the insulating substrate, Forming a gate insulating film on the gate wiring; Forming a semiconductor layer on the gate insulating film, Forming a data line including a data line, a source electrode, and a drain electrode on the semiconductor layer Forming a transparent carbon film pattern having a contact hole exposing the drain electrode, A pixel electrode to be connected to the drain electrode through the contact hole Forming a thin film transistor substrate for a liquid crystal display device. The method of claim 8, wherein the forming of the transparent carbon film pattern is performed. Supplying a hydrocarbon gas and a fluorine gas into the ion plating apparatus; And depositing a carbon material generated by reacting the hydrocarbon gas with plasma on the data line and the gate insulating film to form a transparent carbon film. The method of claim 8, wherein in the forming of the transparent carbon film pattern, the transparent carbon film pattern is a diamond-like carbon film. The method of manufacturing a thin film transistor substrate for a liquid crystal display device according to claim 8, wherein the dielectric constant of the transparent carbon film pattern is 2 to 3.5. The method of manufacturing a thin film transistor substrate for a liquid crystal display device according to claim 8, wherein the transparent carbon film pattern has a thickness of 1 μm to 4 μm. 10. The method of claim 8, wherein the transparent carbon film has a visible light transmittance of 85% to 95%. The method of claim 8, wherein the transparent carbon film pattern comprises 0.01% to 0.5% wt of fluorine.

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