KR100694577B1 - Array substrate for Liquid crystal display and method for fabricating thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a pad portion which is an input portion of an array substrate for liquid crystal display devices.

In order to apply a signal to the liquid crystal panel, a driving circuit is connected to the data pad for applying the signal to the data wiring and the gate pad for applying the signal to the gate wiring in various ways.

Conventionally, as one method for attaching the circuit, a driving circuit is attached on a polymer film, and the polymer film with the driving circuit is attached to the gate pad part and the data pad part by using a conductive adhesive. The circuit was mounted on the liquid crystal panel. In this case, the plurality of pads have a structure in which a signal is applied through each transparent electrode separately patterned. However, since the transparent electrode patterns are formed in a planar proximity to each other, there is a problem that may be short-circuited with each other by moisture or foreign matter left after cleaning.

The present invention for solving the above problems is to propose a structure that does not form a transparent electrode pattern on each of the pads, to prevent the occurrence of a short circuit between each pad due to moisture or foreign matter.

Description

Array substrate for liquid crystal display device and manufacturing method thereof             

1 is a view showing a general liquid crystal display device,

2 is a plan view briefly illustrating a structure of a liquid crystal panel in which a driving circuit is mounted;

3 is a plan view schematically showing a part of a conventional array substrate for a liquid crystal display device;

4 is a cross-sectional view taken along line III-III ′, IV-IV ′, and V-V ′ of FIG. 3;

5A through 5D are cross-sectional views taken along the line III-III ′, IV-IV ′, and V-V ′ of FIG. 3, according to a process sequence according to the present invention.

6 is a cross-sectional view showing the TCP attached to the array substrate produced in accordance with the present invention.

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

134: gate pad 138: data pad

149: TCP 151: conductive particles (conductive balls)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an array substrate for a liquid crystal display device, and more particularly, to a structure of each pad that is an input portion of a data line and a gate line to which a driving circuit is connected.

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.

Therefore, if the molecular arrangement direction of the liquid crystal is arbitrarily adjusted, the molecular arrangement of the liquid crystal is changed, and image information can be expressed by a characteristic that light is refracted by the optical anisotropy of the liquid crystal.

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

In general, the structure of a liquid crystal panel, which is a basic component of a liquid crystal display, will be described.

1 is a view schematically showing a general liquid crystal display device.

As shown, the liquid crystal display includes a color filter 7 including a black matrix 6 and a sub-color filter (red, green, blue) 8 and an upper substrate on which a transparent common electrode 18 is formed on the color filter. And a lower substrate 22 having an array wiring including a pixel region P and a pixel electrode 17 formed on the pixel region, and a switching element T. The upper substrate 5 and the lower substrate are formed of the lower substrate 22. The liquid crystal 14 is filled between the substrates 22.

The lower substrate 22 is also referred to as an array substrate, and the thin film transistor T, which is a switching element, is positioned in a matrix type, and the gate wiring 13 and the data wiring 15 passing through the plurality of thin film transistors cross each other. Is formed.

The pixel area P is an area defined by the gate line 13 and the data line 15 intersecting each other. The pixel electrode 17 formed on the pixel region P uses a transparent conductive metal having relatively high light transmittance, such as indium-tin-oxide (ITO).

In the liquid crystal display device configured as described above, the liquid crystal layer 14 disposed on the pixel electrode 17 is oriented by a signal applied from the thin film transistor T, and the liquid crystal layer is aligned according to the degree of alignment of the liquid crystal layer. The image can be represented in a manner that controls the amount of light that passes through layer 14.

In the liquid crystal display device configured as described above, a driving circuit for applying a signal to the gate wiring and the data wiring is mounted, and various mounting methods are also provided.

Examples of the technology for mounting the driving circuit on the liquid crystal panel include TCP and COG technology.

The TCP (tape carrier package) technology is a package for mounting a driving circuit chip on a polymer film.                         

In a liquid crystal display device, since it is easy to bend along the module side, etc., the ratio of the total area to the effective area of a module can be enlarged, and it is a technique widely used.

In addition, there is an advantage that the repair is easier than other technologies.

In the COG (chip on glass) technology, unlike the TCP technology, the driving circuit chip is directly mounted on the liquid crystal panel.

The COG method is advantageous in that cost is reduced and reliability is improved.

However, there is a problem that the repair of the defect is difficult and the size of the panel increases due to the pad area for circuit mounting.

Nowadays, the TCP technology is used to improve the reliability problem due to the rapid development of the TCP technology, to improve the cost problem by mass production, and to use the TCP in mounting the driving circuit.

2 is a plan view showing a configuration of a liquid crystal panel in which a driving circuit is mounted in the TCP method.

As shown, the TCP 33 including the driving circuit 31 is attached to one side or both sides of the liquid crystal panel 11.

At this time, the TCP 33 is attached to the PCB substrate 35 and the liquid crystal panel 11 at which the circuit is configured to transfer the gate signal and the data signal transmitted from the PCB substrate 35 to the liquid crystal panel. do.

For this purpose, the signal wiring (lead line) of the TCP 33 connected to the driving circuit chip 31 is attached to the gate pad or data pad of the liquid crystal panel with a conductive adhesive.                         

3 is a plan view schematically illustrating a portion of an array substrate that is a first substrate of a liquid crystal panel to which the TCP is attached.

As shown in the drawing, the array substrate 22 is configured such that the gate wiring 13 and the data wiring 15 cross each other to define the pixel region P. As shown in FIG.

A gate pad 14 having a predetermined area is formed at the end of the gate wiring 13, and a data pad 16 having a predetermined area is formed at the end of the data wiring 15.

Each pad unit is a signal input unit connected to the TCP (33 in FIG. 3) to receive a gate signal and a data signal.

As described with reference to FIG. 1, a gate electrode 27 connected to the gate line 13 to receive a gate signal and a source connected to the data line 15 to receive a data signal at a point where the two wires cross each other. The thin film transistor T including the electrode 21, the drain electrode 23, and the active layer 25 is formed.

In addition, the pixel region P includes a transparent pixel electrode 17 connected to the drain electrode 23 to which a data signal is applied.

4 is a cross-sectional view showing a cross section of the array substrate cut along lines III-III ′, IV-IV ′, and V-V ′ of FIG. 3 and the attachment state of the aforementioned TCP.

The portion shown is the thin film transistor T of the array substrate 22, the gate pad 14, and the data pad 16.

When the liquid crystal panel is manufactured, TCP 33 is attached to the gate pad 14 and the data pad 16, respectively, as shown.

That is, the signal wiring formed in the TCP 33 is connected to each of the pads 14 and 16. At this time, the signal is ultimately transmitted by a conductive adhesive bonding the signal wiring 19 of the TCP 33 and the pads 14 and 16.

The conductive adhesive is referred to as an anisotropic conductive film (ACF) as an anisotropic conductive film. The conductive adhesive contains conductive particles (conductive balls) 25 in a kind of heat curable resin, and when the panel and the TCP to be conductively bonded are aligned and thermally compressed, electrical contact is made in the vertical direction.

At this time, the diameter of the said electroconductive particle can be up to 50 micrometers.

In the above-described configuration of the array substrate, the transparent conductive metals 17a and 17b are patterned on the respective pads so that the conductive particles 25 are in electrical contact with the transparent electrode patterns 17a and 17b.

In this manner, the TCP 33 and the liquid crystal panel 22 are attached.

However, in the conventional array substrate 22 structure, the transparent electrode patterns 17a and 17b in contact with the conductive balls (conductive particles) 25 are configured to be spaced apart by a predetermined interval in plan view.

At this time, after cleaning the liquid crystal panel, if moisture remains due to poor drying or foreign matter 34 exists between the transparent electrode patterns, the pad and the pad are electrically contacted with each other to cause short circuit failure. do.

Therefore, in order to solve the above problem, the pad portion to which the signal is input is manufactured by fabricating the array substrate 22 in such a configuration that the transparent electrode patterns 17a and 17b which cause the short circuit are not formed. The purpose is to prevent short circuit defects.

An array substrate for a liquid crystal display device according to the present invention for achieving the above object is a substrate; A gate wiring formed in one direction on the substrate and including a gate pad at one end thereof; A data line intersecting with the gate line via an insulating film, the data line including a data pad at one end thereof; A thin film transistor formed at a point where the gate line and the data line cross each other; A drain contact formed on the substrate including the thin film transistor, the data line, the data pad, the gate line, and the gate pad, and exposing each of the drain electrode, the data pad, and the gate pad of the thin film transistor. A protective film having a hole, a data pad contact hole, and a gate pad contact hole; A transparent pixel electrode formed on the passivation layer and contacting the drain electrode through the drain contact hole; And a tape carrier package (TCP) in which conductive particles on signal wirings respectively corresponding to the data pad contact hole and the gate pad contact hole are in direct contact with the data pad and the gate pad.

In the array substrate for a liquid crystal display device as described above, the thin film transistor includes a gate electrode connected to the gate wiring, a source electrode, the drain electrode, and an active layer.

According to an aspect of the present invention, there is provided a method of manufacturing an array substrate for a liquid crystal display device, the method including: forming a gate wiring on one end of a substrate and including a gate pad at one end thereof; Forming an insulating film on the substrate including the gate wiring and the gate pad, and forming a data wiring on the insulating film, the data wiring including a data pad at one end thereof and crossing the gate wiring; Forming a thin film transistor at a point where the gate line and the data line cross each other; A drain contact hole and data exposing each of the drain electrode, the data pad, and the gate pad of the thin film transistor on the substrate including the thin film transistor, the data line, the data pad, the gate line, and the gate pad. Forming a protective film having a pad contact hole and a gate pad contact hole; Forming a transparent pixel electrode on the passivation layer, the transparent pixel electrode contacting the drain electrode through the drain contact hole; And attaching a tape carrier package (TCP) in which conductive particles on signal wires respectively corresponding to the data pad contact hole and the gate pad contact hole are in direct contact with the data pad and the gate pad.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

Example

The configuration of the array substrate according to the present invention as described above can be manufactured through the process of Figure 5a to 5d below.

5A through 5D are cross-sectional views illustrating a process sequence by cutting along lines III-III ′, IV-IV ′, and V-V ′ of FIG. 3.

(The planar structure of the array substrate according to the present invention is similar to that of FIG. 3, see FIG. 3).

First, as shown in FIG. 5A, a first conductive metal is deposited and patterned on a transparent substrate 100 to form a gate wiring including the gate electrode 132 (13 in FIG. 3) and an end of the gate wiring. A gate pad 134 having a predetermined area is formed in the.

The first conductive metal is formed by selecting one of conductive metal groups including aluminum (Al), copper (Cu), tungsten (W), chromium (Cr), and molybdenum (Mo).                     

An insulating layer 141, an amorphous silicon (a-Si: H) layer, and an amorphous silicon (n + a-Si: H) layer containing impurities are stacked on the substrate 100 on which the gate electrode 132 is formed. The island-like active layer 135 and the ohmic contact layer 137 are formed.

As shown in FIG. 5B, one of the conductive metal groups as described above is selected on the entire surface of the substrate 100 on which the ohmic contact layer 137 is formed to form a conductive metal film.

 The conductive metal film is patterned to intersect the gate wiring (15 in FIG. 3) to define a pixel region (P in FIG. 3), and a source electrode 133 connected to the data wiring. ) And drain electrodes 136 spaced apart from each other by a predetermined interval.

In this case, a data pad 138 having a predetermined area is formed at the end of the data line.

Next, as shown in FIG. 5C, a protective layer 139 is formed on the entire surface of the substrate 100 on which the data pad and the like are formed.

Successively, the protective layer 139 is patterned to form a drain contact hole 141 exposing a portion of the drain electrode 136 and a gate pad contact hole 143 exposing a portion of the gate pad 134. And a data pad contact hole 145 exposing a portion of the data pad 138.

Next, as illustrated in FIG. 5D, a transparent conductive metal is deposited and patterned on the patterned protective layer 139 to form the pixel electrode 147 in contact with the drain electrode 136.

In this way, the array substrate according to the present invention can be manufactured.                     

In the above-described configuration, a feature of the present invention is not to form a transparent electrode pattern in contact with the gate pad and the data pad, unlike the prior art.

FIG. 6 is a view showing a shape in which the TCP is attached to an array substrate according to the present invention having the configuration of FIG. 5D.

As shown, the conductive particles 151 of the conductive adhesive bonding the lead wire 150 of the TCP 149 and the pad portions P1 and P2 are in direct contact with the gate pad 134 and the data pad 138. It becomes the shape that becomes.

In this way, even if water or foreign matter exists between the pads, the pads cannot be electrically contacted.

Therefore, the arrangement of the array substrate according to the present invention has an effect of improving the yield of the liquid crystal panel because short circuit defects due to foreign matter do not occur between the pads and the pads.

Claims (3)

A substrate; A gate wiring formed in one direction on the substrate and including a gate pad at one end thereof; A data line intersecting with the gate line via an insulating film, the data line including a data pad at one end thereof; A thin film transistor formed at a point where the gate line and the data line cross each other; A drain contact formed on the substrate including the thin film transistor, the data line, the data pad, the gate line, and the gate pad, and exposing each of the drain electrode, the data pad, and the gate pad of the thin film transistor. A protective film having a hole, a data pad contact hole, and a gate pad contact hole; A transparent pixel electrode formed on the passivation layer and contacting the drain electrode through the drain contact hole; A tape carrier package (TCP) in which conductive particles on a signal line corresponding to the data pad contact hole and the gate pad contact hole are in direct contact with the data pad and the gate pad; Array substrate for a liquid crystal display device comprising a. The method of claim 1, And the thin film transistor includes a gate electrode connected to the gate wiring, a source electrode, the drain electrode, and an active layer. Forming a gate wiring on the substrate in one direction and including a gate pad at one end thereof; Forming an insulating film on the substrate including the gate wiring and the gate pad, and forming a data wiring on the insulating film, the data wiring including a data pad at one end thereof and crossing the gate wiring; Forming a thin film transistor at a point where the gate line and the data line cross each other; A drain contact hole and data exposing each of the drain electrode, the data pad, and the gate pad of the thin film transistor on the substrate including the thin film transistor, the data line, the data pad, the gate line, and the gate pad. Forming a protective film having a pad contact hole and a gate pad contact hole; Forming a transparent pixel electrode on the passivation layer, the transparent pixel electrode contacting the drain electrode through the drain contact hole; Attaching a tape carrier package (TCP) in which conductive particles on signal wirings respectively corresponding to the data pad contact hole and the gate pad contact hole are in direct contact with the data pad and the gate pad; Method of manufacturing an array substrate for a liquid crystal display device comprising a.

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