KR20080048665A - Thin film transistor array substrate and its manufacturing method of ips liquid crystal display device - Google Patents

Abstract

A TFT(Thin Film Transistor) array substrate of an IPS(In-Plane Switching) mode LCD(Liquid Crystal Display) and a manufacturing method thereof are provided to reduce the brightness at a black state when there is no the applied voltage, thereby increasing the contrast ratio of the LCD. A gate line is arrayed on a substrate with a direction. A common line(51b) is formed with the same material as the gate line in parallel. A common electrode(51c) is branched from the common line and arrayed vertically to the gate line. The first insulating layer is formed on the gate line, common line and common electrode. A data line(55a) is formed on the first insulating layer, crossed vertically to the gate line and defines a pixel area. A pixel electrode(60a) is arranged alternately against the common electrode within the pixel area and formed with the same materials as the data line. A TFT is formed within the pixel area. The second insulating layer is formed at the data line and the pixel electrode. The first hole(58a) exposes the center of the pixel electrode to the second insulating layer. The second hole(58b) exposes the first insulating layer corresponding to the center of the common electrode.

Description

Thin film transistor array substrate for a transverse electric field liquid crystal display device and a method of manufacturing the same {THIN FILM TRANSISTOR ARRAY SUBSTRATE AND ITS MANUFACTURING METHOD OF IPS LIQUID CRYSTAL DISPLAY DEVICE}

1 and 2 are a plan view and a cross-sectional view showing a thin film transistor array substrate of a general transverse electric field liquid crystal display device.

3A to 5A are plan views illustrating a method of manufacturing a thin film transistor array substrate of a transverse electric field liquid crystal display device according to an exemplary embodiment of the present invention.

3B to 5B are cross-sectional views showing lines II ′ and II-II ′ of FIGS. 3A to 5A.

<Description of the code | symbol about the principal part of drawing>

50: substrate 51: gate wiring

51a: gate electrode 52: gate insulating film

53: semiconductor layer 54: ohmic contact layer

55a: data wirings 55b and 55c: source electrode and drain electrode

57: protective films 58a, 58b: first and second holes

60a: pixel electrode

The present invention relates to a thin film transistor array substrate of a liquid crystal display device and a manufacturing method thereof, and more particularly, to a thin film transistor array substrate of a transverse electric field type liquid crystal display device and a manufacturing method thereof.

In general, a liquid crystal display (LCD) displays an image corresponding to a data signal on a panel by adjusting a data signal supplied to the liquid crystal cells arranged in a matrix form on the liquid crystal panel. .

In general, the driving principle of the liquid crystal display device uses the optical anisotropy and polarization of the liquid crystal. Since the liquid crystal is thin and long in structure, the liquid crystal has directivity in the arrangement of molecules, and the direction of the molecular arrangement can be controlled by artificially applying an electric field to the liquid crystal.

Accordingly, when the molecular arrangement direction of the liquid crystal is arbitrarily adjusted, the molecular arrangement of the liquid crystal is changed, and light is refracted in the molecular arrangement direction of the liquid crystal due to optical anisotropy to express image information.

Currently, active matrix LCDs (AM-LCDs) in which thin film transistors and pixel electrodes connected to the thin film transistors are arranged in a matrix manner have attracted the most attention due to their excellent resolution and video performance.

Among the liquid crystal display devices described above, a transverse electric field liquid crystal display device having a common electrode formed on an upper substrate and a pixel electrode formed on a lower substrate drives liquid crystals by an electric field applied up and down, and has characteristics such as transmittance and aperture ratio. This is excellent, and the common electrode of the top plate serves as a ground to prevent the destruction of the liquid crystal cell due to static electricity.

However, the liquid crystal drive by the electric field applied up-down has a disadvantage that the viewing angle characteristics are not excellent. Therefore, new techniques have been proposed to overcome the above disadvantages. The transverse electric field liquid crystal display device to be described below has an advantage of excellent viewing angle characteristics by a liquid crystal driving method using a horizontal electric field through two electrodes formed on one substrate.

The following description relates to a transverse electric field liquid crystal display device.

1 and 2 are a plan view and a cross-sectional view illustrating a thin film transistor array substrate of a general transverse electric field liquid crystal display device.

Referring to FIG. 2, which is cross-sectional views taken along lines II ′ and II-II ′ of FIGS. 1 and 1, a thin film transistor array substrate of a transverse electric field liquid crystal display device may include a gate wiring 151 on a substrate 150 in a horizontal direction. ) And the common wiring 151b are formed to be parallel to each other. A plurality of common electrodes 151c branched from the common wiring 151b are formed on the common wiring 151b, and one side of the gate wiring 151 is formed. The gate electrode 151a is formed to protrude.

A gate insulating film 152 is formed on the substrate 150 on which the gate wiring 151, the common wiring 151b, and the gate electrode 151a are formed, and the gate electrode 151a of the substrate on which the gate insulating film 152 is formed. ) Is formed to form a semiconductor layer 153a, which is a channel layer of the thin film transistor.

The vertical data line 155a is formed to be perpendicular to the gate line 151 and the common line 151b formed in the horizontal direction. Therefore, one pixel area is defined by the vertically crossed gate line 151 and the data line 155a.

In addition, a source electrode 155b is formed in the data line 155a on the semiconductor layer 153a so as to overlap a predetermined area with the gate electrode 151, and the drain electrode is positioned at a position corresponding to the source electrode 155b. 155c is formed.

In addition, a passivation layer 157 is formed on the entire surface of the substrate where the source electrode 155b and the drain electrode 155c are formed, and a contact hole is formed in the passivation layer 157 so as to be exposed to the drain electrode 155c.

In addition, the pixel electrode 160a is formed on the passivation layer 157 so as to cross the common electrode 151c formed in the pixel region, and the pixel electrode 160a is a drain electrode through the contact hole formed in the passivation layer 157. It is in contact with 155c.

Although not shown, an alignment layer is coated on the entire surface of the thin film transistor array substrate on which the pixel electrode 160a is formed. Then, a thin film transistor array substrate coated with an alignment film and a color filter array substrate disposed to face each other with a liquid crystal layer interposed therebetween are provided. The color filter array substrate includes a color filter, a black matrix, and the like.

Such a transverse electric field type liquid crystal display device displays a black state when a voltage is not applied to two electrodes formed on one substrate 150, that is, the common electrode 151c and the pixel electrode 160a. When voltage is applied to the electrode 151c and the pixel electrode 160a, a white state is displayed.

It is necessary to increase the contrast ratio represented by the contrast in the white state and the black state, but one method may be to lower the luminance of the black state.

Meanwhile, an area in which the pixel electrode 160a or the common electrode 151c is formed protrudes from adjacent areas, and an area adjacent to the area in which the pixel electrode 160a or the common electrode 151c is formed has a step.

As described above, in the stepped region R generated due to the formation of the electrodes 160a and 151c, the rubbing process is caused during the rubbing process performed on the deposited alignment layer, and the liquid crystal positioned on the region R The array is disturbed. This arrangement distortion phenomenon of the liquid crystal transmits the backlight light 159b on the rear surface of the substrate to cause light leakage due to the alignment distortion of the liquid crystal, which causes a problem of increasing the luminance in the black state.

Accordingly, an object of the present invention for solving the above problems is to prevent the light leakage phenomenon to reduce the brightness in the black state when the voltage is not applied to increase the contrast ratio of the liquid crystal display device thin film transistor of the transverse electric field type liquid crystal display device And to provide a method for producing the same.

A thin film transistor array substrate of a transverse liquid crystal display according to the present invention for achieving the above object is a substrate, a gate wiring arranged in one direction on the substrate, a common wiring formed in parallel with the same material as the gate wiring And a common electrode branched from the common wiring and arranged perpendicular to the gate wiring, a first insulating film formed on the gate wiring, a common wiring and a common electrode, and formed on the first insulating film. A data line which is vertically crossed to define a pixel area, a pixel electrode disposed in the pixel area so as to alternate with the common electrode, and formed of the same material as the data line, a thin film transistor formed in the pixel inverse, and A second insulating film formed on the data line and the pixel electrode, and a center of the pixel electrode on the second insulating film A and a second hole exposing the first insulation film corresponding to the central portion of the common electrode and a first hole which exposes.

The diameter of the first hole is smaller than the line width of the common electrode, and the diameter of the second hole is smaller than the line width of the pixel electrode.

The thin film transistor may include a gate electrode protruding from the gate wiring to a pixel region, a semiconductor layer and an ohmic contact layer formed on the gate electrode, and protruding from the data wiring and on the first insulating layer corresponding to the gate electrode. A source electrode and a drain electrode formed in the.

The drain electrode is connected to the pixel electrode and formed of the same material.

The gate wiring, the common wiring, the gate electrode and the common electrode, the source and drain electrodes, the pixel electrode, and the data wiring have a specific resistance of copper (Cu), aluminum (Al), aluminum alloy (AlNd: Aluminum Neodymium), and molybdenum (Mo). ), Chromium (Cr), titanium (Ti), tantalum (Ta), and molybdenum-tungsten (MoW).

According to an aspect of the present invention, there is provided a method of fabricating a thin film transistor array substrate of a transverse liquid crystal display device, the method including: providing a substrate, and forming a gate wiring, a common wiring, a gate electrode, and a common electrode on the substrate using the same material. Forming a first insulating film on the substrate including the gate electrode, forming a source and a drain electrode, a pixel electrode, and a data wiring on the gate insulating film with the same material; Forming a second insulating film on the substrate including the first hole exposing the center of the pixel electrode by patterning the second insulating film and a second hole exposing the first insulating film corresponding to the center of the common electrode; Forming a step.

The diameter of the first hole is smaller than the line width of the common electrode, and the diameter of the second hole is smaller than the line width of the pixel electrode.

Forming a semiconductor layer and an ohmic contact layer under the source and drain electrodes on the gate insulating layer.

The drain electrode is formed of the same material as the pixel electrode.

The gate wiring, the common wiring, the gate electrode and the common electrode, the source and drain electrodes, the pixel electrode, and the data wiring have a specific resistance of copper (Cu), aluminum (Al), aluminum alloy (AlNd: Aluminum Neodymium), and molybdenum (Mo). ), Chromium (Cr), titanium (Ti), tantalum (Ta), and molybdenum-tungsten (MoW).

An embodiment of a thin film transistor array substrate of a transverse electric field liquid crystal display device and a method of manufacturing the same according to the present invention having the above characteristics will be described in detail with reference to the accompanying drawings.

5A and 5B are plan and cross-sectional views illustrating a thin film transistor array substrate of a transverse electric field liquid crystal display according to an exemplary embodiment of the present invention.

As shown in FIGS. 5A and 5B, the thin film transistor array substrate of the transverse electric field liquid crystal display device is formed on the substrate 50 with the gate wiring 51 and the common wiring 51b parallel to each other in the horizontal direction. The plurality of common electrodes 51c branched from the common wiring 51b are formed on the common wiring 51b, and the gate electrode 51a protrudes from one side of the gate wiring 51.

The gate insulating film 52 is formed on the substrate 50 on which the gate wiring 51, the common wiring 51b, and the gate electrode 51a are formed, and the gate electrode 51a of the substrate on which the gate insulating film 52 is formed. The semiconductor layer 53 and the ohmic contact layer 54, which are channel layers of the thin film transistor, are formed to overlap each other.

A vertical data line 55a formed perpendicular to the gate line 51 and the common line 51b formed in the horizontal direction is formed. Therefore, one pixel area is defined by the vertically crossed gate line 51 and the data line 55a.

In the data line 55a on the semiconductor layer 53, a source electrode 55b is formed to overlap a predetermined area with the gate electrode 51, and a drain electrode is positioned at a position corresponding to the source electrode 55b. 55c is formed, and the pixel electrode 60a connected to the drain electrode 55c is formed at a position alternated with the common electrode 51b.

The common electrode 51c and the pixel electrode 60a have a structure bent at the center.

As described above, the thin film transistor is formed by providing the gate electrode 51a, the semiconductor layer 53, the ohmic contact layer 54, the source electrode 55b, and the drain electrode 55c.

The passivation layer 57 is formed on the entire surface of the substrate on which the source electrode 55b, the drain electrode 55c, and the pixel electrode 60a are formed.

The protective layer 57 is formed with a first hole 58a formed to correspond to the common electrode 51c and a second hole 58b formed to correspond to the pixel electrode 60a.

The first hole 58a is formed to expose the gate insulating layer 52 by removing the passivation layer 57 protruding by the common electrode 51c, and the diameter of the first hole is smaller than the line width of the common electrode 51c. Be sure to

The second hole 58b is formed to expose the pixel electrode 60a by removing the passivation layer 57 protruding by the pixel electrode 60a, and the diameter of the second hole is smaller than the line width of the pixel electrode 60a. To form.

Meanwhile, since the first and second holes 58a and 58b are formed, the passivation layer 57 having the first hole 58a corresponding to the common electrode 51c and the second hole corresponding to the pixel electrode 60a are formed. The passivation layer 57 formed with the 58b has adjacent stepped regions R 'and adjacent passivation layers, respectively. In this case, when the first and second holes are formed to have diameters smaller than the line widths of the common electrode and the pixel electrode as described above, the stepped regions R 'correspond to both sides of the common electrode or both sides of the pixel electrode, respectively. Therefore, even if the arrangement of the liquid crystals 59a is disturbed in the region R 'as described above, the common electrode 51a and the pixel electrode 60a formed of the metal material for the source drain and the gate, respectively, are backlit on the back of the substrate. By blocking (59b) it is possible to prevent light leakage caused by the distortion of the liquid crystal.

A method of manufacturing a transverse electric field type liquid crystal display device according to the present invention as described above will be described below.

3A to 5A are plan views illustrating a method of manufacturing a transverse electric field type liquid crystal display device according to an exemplary embodiment of the present invention, and FIGS. 3B to 5B are lines II ′ and II-II ′ of FIGS. 3A to 5A. It is sectional drawing which shows a shipboard.

3A and 3B, after depositing a metal material on the substrate 50, a patterning process such as a photolithography process is performed to perform a gate wiring 51, a common wiring 51b, and a gate wiring 51. The gate electrode 51a branched from the ()) and the common electrode 51c branched from the common wiring 51b are formed.

The common electrode 51c is formed to surround the pixel area together with the common wiring 51b and has a bent structure at the center, but may have a straight structure not shown in the drawing, or may have a bent structure several times. .

The metal materials forming the gate wiring 51, the common wiring 51b, the gate electrode 51a, and the common electrode 51c may be copper (Cu), aluminum (Al), or aluminum alloy (AlNd) having a specific resistance. ), Molybdenum (Mo), chromium (Cr), titanium (Ti), tantalum (Ta), molybdenum-tungsten (MoW) and other low-resistance metal material is deposited through a sputtering method.

Next, as shown in FIGS. 4A and 4B, the gate insulating layer 52, the amorphous silicon layer 53, and the n + amorphous silicon layer 54 are formed on the entire surface of the lower substrate 50 on which the gate electrode 51a is formed. ) And metal materials are formed sequentially.

The gate insulating layer 52 is formed by depositing silicon oxide (SiOx) or silicon nitride (SiNx), which is an inorganic insulating material having good dielectric breakdown voltage, by a plasma enhanced chemical vapor deposition method, and an n + amorphous silicon layer 54 and The amorphous silicon layer 53 is formed by depositing a plasma chemical vapor deposition method using a SiH ₄ and H ₂ mixed gas. In addition, the metal material is copper (Cu), aluminum (Al), aluminum alloy (AlNd: Aluminum Neodymium), molybdenum (Mo), chromium (Cr), titanium (Ti), tantalum (Ta), molybdenum-tungsten having a specific resistance A low resistance metal material such as (MoW) is deposited through a sputtering method.

Subsequently, a patterning process such as a photolithography process using a halftone mask or the like is performed on the metal material, such that the semiconductor layer 53, the ohmic contact layer 54, the source / drain electrodes 55b and 55c, and the data line ( 55a and the pixel electrode 60a are formed.

At this time, the semiconductor layer 53, the ohmic contact layer 54 and the source / drain electrodes 55b and 55c may be simultaneously formed as described above, but the semiconductor layer 53 and the ohmic contact layer 54 are formed through a patterning process. ) May be formed first, followed by depositing and patterning a metal layer thereon to form source / drain electrodes 55b and 55c.

In the meantime, the pixel electrode 60a is formed on the gate insulating layer 52 at the position alternate with the common electrode 51c during the process of forming the source / drain electrodes 55b and 55c and the data line 55a. The drain electrode 55b formed in the region adjacent to the gate line 51 and the pixel electrode 60a formed in the pixel region are connected to each other in the region in which the drain electrode 55b is formed. A contact hole formed in the protective film is not required to expose 55b).

Through the above process, a thin film transistor TFT formed of the gate electrode 51a, the semiconductor layer 53, the source electrode 55b, and the drain electrode 55c is formed. The thin film transistor TFT forms a source electrode 55b in a 'U' shape, and a drain electrode 55c is arranged between the 'U' shaped source electrode 55b to form a 'U' shaped channel region. It can be formed to have.

Next, as shown in FIGS. 5A and 5B, the protective film 57 is formed on the entire lower substrate 50 including the thin film transistor TFT by vapor deposition such as PECVD.

Subsequently, a patterning process such as a photo and an etching process is performed on the passivation layer 57 to remove the passivation layer 57 protruding by the common electrode 51c and the pixel electrode 60a, thereby removing the first and second holes ( 58a, 58b).

The first hole 58a is formed to expose the gate insulating layer 52 by removing the passivation layer 57 protruding by the common electrode 51c, and the diameter of the first hole is smaller than the line width of the common electrode 51c. Be sure to

The second hole 58b is formed to expose the pixel electrode 60a by removing the passivation layer 57 protruding by the pixel electrode 60a, and the diameter of the second hole is smaller than the line width of the pixel electrode 60a. To form.

Meanwhile, since the first and second holes 58a and 58b are formed, the passivation layer 57 having the first hole 58a corresponding to the common electrode 51c and the second hole corresponding to the pixel electrode 60a are formed. The passivation layer 57 formed with the 58b has adjacent stepped regions R 'and adjacent passivation layers, respectively. In this case, when the first and second holes are formed to have diameters smaller than the line widths of the common electrode and the pixel electrode as described above, the stepped regions R 'correspond to both sides of the common electrode or both sides of the pixel electrode, respectively. Therefore, even if the arrangement of the liquid crystals 59a is disturbed in the region R 'as described above, the common electrode 51a and the pixel electrode 60a formed of the metal material for the source drain and the gate, respectively, are backlit on the back of the substrate. By blocking (59b) it is possible to prevent light leakage caused by the distortion of the liquid crystal.

On the other hand, the present invention described above is not limited to the above-described embodiment and the accompanying drawings, it is possible that various substitutions, modifications and changes within the scope without departing from the technical spirit of the present invention. It will be apparent to those of ordinary skill in Esau.

As described above, the transverse electric field type liquid crystal display device and its manufacturing method form first and second holes having a diameter smaller than the line width of the common electrode and the pixel electrode, and the common electrode and the pixel electrode for the source drain and the gate. By forming the metal material, the backlight of the back surface of the substrate is blocked by the common electrode and the pixel electrode, thereby preventing the light leakage caused by the arrangement distortion of the liquid crystal.

Therefore, the light leakage phenomenon can be prevented as described above, thereby reducing the luminance in the black state when no voltage is applied, thereby increasing the contrast ratio of the liquid crystal display.

Claims (14)

Substrate, A gate wiring arranged in one direction on the substrate; A common wiring formed in parallel with the same material as the gate wiring; A common electrode branched from the common wiring and arranged perpendicular to the gate wiring; A first insulating film formed on the gate wiring, common wiring, and common electrode; A data line formed on the first insulating film, the data line crossing the gate line perpendicularly to define a pixel region; A pixel electrode disposed in the pixel region so as to be alternate with the common electrode, and formed of the same material as the data line; A thin film transistor formed in the pixel area; A second insulating film formed on the data line and the pixel electrode; And a second hole exposing a center portion of the pixel electrode to the second insulating layer and a second hole exposing a first insulating layer corresponding to the center portion of the common electrode. The thin film transistor array substrate of claim 1, wherein a diameter of the first hole is smaller than a line width of the pixel electrode. The thin film transistor array substrate of claim 1, wherein the diameter of the second hole is smaller than the line width of the common electrode. The thin film transistor of claim 1, wherein the thin film transistor is A gate electrode protruding from the gate wiring into a pixel region; A semiconductor layer and an ohmic contact layer formed on the gate electrode; And a source electrode and a drain electrode protruding from the data line and formed on the first insulating film corresponding to the gate electrode. The method of claim 1 or 4, wherein the drain electrode The thin film transistor array substrate of the transverse electric field liquid crystal display device, characterized in that formed in the same material as the pixel electrode. The method of claim 1, wherein the gate wiring, the common wiring, the gate electrode and the common electrode Resistive copper (Cu), aluminum (Al), aluminum alloy (AlNd: Aluminum Neodymium), molybdenum (Mo), chromium (Cr), titanium (Ti), tantalum (Ta), molybdenum-tungsten (MoW) A thin film transistor array substrate of a transverse electric field liquid crystal display device, characterized in that formed of one metal. The method of claim 1, wherein the source and drain electrodes, the pixel electrode and the data wiring are Resistive copper (Cu), aluminum (Al), aluminum alloy (AlNd: Aluminum Neodymium), molybdenum (Mo), chromium (Cr), titanium (Ti), tantalum (Ta), molybdenum-tungsten (MoW) A method of manufacturing a thin film transistor array substrate of a transverse electric field liquid crystal display device, characterized in that it is formed of one metal. Providing a substrate, Forming a gate wiring, a common wiring, a gate electrode, and a common electrode of the same material on the substrate; Forming a first insulating film on the substrate including the gate electrode; Forming a source and a drain electrode, a pixel electrode, and a data wiring on the gate insulating layer using the same material; Forming a second insulating film on the substrate including the data line; Patterning the second insulating film to form a first hole exposing the central portion of the pixel electrode and a second hole exposing the first insulating layer corresponding to the central portion of the common electrode; Method of manufacturing a transistor array substrate. The thin film transistor array substrate of claim 8, wherein the diameter of the first hole is smaller than the line width of the pixel electrode. The thin film transistor array substrate of claim 8, wherein a diameter of the second hole is smaller than a line width of the common electrode. 10. The method of claim 8, further comprising forming a semiconductor layer and an ohmic contact layer on the gate insulating layer or under the source and drain electrodes. The method of claim 8, wherein the drain electrode A thin film transistor array substrate of a transverse electric field liquid crystal display device, wherein the thin film transistor is formed of the same material as the pixel electrode. The method of claim 8, wherein the gate wiring, the common wiring, the gate electrode and the common electrode Resistive copper (Cu), aluminum (Al), aluminum alloy (AlNd: Aluminum Neodymium), molybdenum (Mo), chromium (Cr), titanium (Ti), tantalum (Ta), molybdenum-tungsten (MoW) A method of manufacturing a thin film transistor array substrate of a transverse electric field liquid crystal display device, characterized in that it is formed of one metal. The method of claim 8, wherein the source and drain electrodes, the pixel electrode and the data wiring are Resistive copper (Cu), aluminum (Al), aluminum alloy (AlNd: Aluminum Neodymium), molybdenum (Mo), chromium (Cr), titanium (Ti), tantalum (Ta), molybdenum-tungsten (MoW) A method of manufacturing a thin film transistor array substrate of a transverse electric field liquid crystal display device, characterized in that it is formed of one metal.

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