KR100816335B1 - Thin film transistor array panel and a method for attaching the integrated circuit for the same - Google Patents

Abstract

The present invention relates to a thin film transistor substrate for a liquid crystal display device, to which a chip on glass (COG) method of directly mounting a driving integrated circuit is mounted on an upper portion of a substrate.

In the thin film transistor substrate according to the present invention, a gate line connected to an end of a gate line and a gate line on an insulating substrate receives a gate signal from an external driving integrated circuit, and is connected to at least two gate pads, and a gate line and a gate connected to the gate pad. A gate wiring including an electrode is formed. A semiconductor layer is formed on an upper portion of the gate insulating layer that covers the gate line, and a data line intersecting the gate line and connected to the end of the data line to define a pixel area, receives a data signal from an external driving integrated circuit, and is connected to at least two or more lines. A data line including a data pad, a source electrode connected to the data line and extending over the semiconductor layer on the gate electrode, and a drain electrode facing the source electrode is formed around the gate electrode. A passivation layer having a drain electrode, a data pad, and a contact hole for exposing the gate pad is formed on the data line and the semiconductor layer, and the drain electrode, the data pad, the pixel electrode connected to the gate pad and the auxiliary data through the contact hole on the passivation layer. Pads and auxiliary gate pads are formed.

In addition, in the case of forming one gate pad and one data pad for each wiring, the length of the pad is formed to be about twice as long as the length of the driving integrated circuit bump.

Therefore, the process of attaching the driving integrated circuit to the thin film transistor substrate according to the present invention can be reworked.

Pads, auxiliary pads, anisotropic conductive particles, driving integrated circuits

Description

Thin film transistor array panel and a method for attaching the integrated circuit for the same}

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

FIG. 2 is a cross-sectional view taken along the line II-II 'of FIG. 1;

3 is a view showing a state in which an anisotropic conductive film is attached to attach a driving integrated circuit to a first auxiliary data pad;

4 is a cross-sectional view taken along line IV-IV 'of FIG. 3 and illustrates a state in which a driving integrated circuit is attached;

FIG. 5 is a view showing a state in which an anisotropic conductive film is attached to attach a driving integrated circuit to a second auxiliary data pad.

FIG. 6 is a cross-sectional view taken along line VI-VI ′ of FIG. 5 and illustrating a state in which a driving integrated circuit is attached;

7 is a layout view of a thin film transistor substrate for a liquid crystal display according to a second exemplary embodiment of the present invention.

FIG. 8 is a cross-sectional view taken along the line VIII-VIII ′ of FIG. 7.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film transistor substrate and a method for attaching a driving integrated circuit using the same, and more particularly, to a thin film transistor substrate for a liquid crystal display device, to which a chip on glass (COG) method for directly mounting a driving integrated circuit is mounted on the substrate. .

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 for controlling the amount of light transmitted by rearranging them.

In general, a plurality of gate lines and data lines intersecting with each other are formed on a thin film transistor array substrate, and a plurality of thin film transistors and pixel electrodes are formed in a matrix-type pixel region in which gate lines and data lines are defined as intersections. Gate pads and data pads are formed at the end of the gate line and the end of the data line, respectively, and the pad portion on which the pad is formed is located outside the display area formed of a set of pixel areas and is not covered by the color filter substrate.

Each pad portion must be electrically connected to a driving integrated circuit which converts an electrical signal into a scan signal and a data signal, respectively, and outputs the wiring signal.

The technology for mounting such a driving integrated circuit in a liquid crystal display device requires a tape automated bonding (TAB) mounting method and a TCP for mounting the driving integrated circuit in a tape carrier package (TCP) to connect to a thin film transistor array substrate. And a COG (chip on glass) mounting method that directly attaches a driving integrated circuit directly onto a glass substrate.

The COG mounting method uses an anisotropic conducting film (ACF) to directly attach the driving integrated circuit to the glass substrate, which does not require TCP and saves a lot of cost. When this happens, it is difficult to rework, so other components cannot be used together.

In the process of attaching the driving integrated circuit to the conventional thin film transistor substrate having a single pad and removing the remaining anisotropic conductive film during the initial work when reworking due to an operation error or a defect of the driving integrated circuit. This is due to the occurrence of damage to the pad portion. The impossibility of rework in the process of attaching such a driving integrated circuit is a major cause of decreasing the yield.

Accordingly, the technical problem of the present invention is to solve such a problem, and an object of the present invention is to provide a thin film transistor substrate that enables rework in a process of attaching a driving integrated circuit.

Another object of the present invention is to provide a method for attaching a driving integrated circuit using the thin film transistor substrate.

The present invention for achieving this problem provides a thin film transistor substrate formed with at least two or more pads for each wiring, or formed with a length of the pad more than twice.

Specifically, in the thin film transistor substrate according to an aspect of the present invention, a gate line is formed on an insulating substrate, and a gate pad is formed at the end of the gate line to receive a gate signal from the outside and transmit the gate signal to the gate line. A data line defining a pixel region intersecting the gate line is insulated from the gate line, and a data pad is formed at the end of the data line to receive the data signal and transmit the data signal to the data line. A thin film transistor connected to the gate line and the data line is formed. A pixel electrode formed in the pixel region and connected to the gate line and the data line through the thin film transistor is formed. Here, at least two gate pads or data pads are formed.

In addition, in the thin film transistor substrate for a liquid crystal display according to another aspect of the present invention, a gate line is formed on an insulating substrate, and a gate pad connected to an end of the gate line to receive a gate signal from an external driving integrated circuit is formed. A data line crossing the gate line and defining a pixel area is formed to be insulated from the gate line, and a data pad connected to an end of the data line to receive a data signal from an external driving integrated circuit is formed. A thin film transistor connected to the gate line and the data line is formed. A pixel electrode formed in the pixel region and connected to the gate line and the data line through the thin film transistor is formed. Here, the gate pad or the data pad is formed at least twice as long as the bump length of the driving integrated circuit.

A method of attaching a driving integrated circuit to a thin film transistor substrate according to one aspect of the present invention is as follows.

First, the anisotropic particles contained in the anisotropic conductive film are attached to the first data pad or the first gate pad of the thin film transistor substrate. Next, the driving integrated circuit is attached to the first data pad or the first gate pad to which the anisotropic particles are attached. The attachment state of the driving integrated circuit is inspected and the electrical evaluation is performed to determine whether there is any defect. When the failure occurs, the driving integrated circuit is detached from the first data pad or the first gate pad to which the anisotropic particles are attached. Next, anisotropic particles included in the anisotropic conductive film are attached to the second data pad or the second gate pad of the thin film transistor substrate. The driving integrated circuit is attached to the second data pad or the third gate pad to which the anisotropic particles are attached. The attachment state of the driving integrated circuit is inspected and the electrical evaluation is performed to determine whether it is defective, and then the attachment of the driving integrated circuit is completed.

A method of attaching a driving integrated circuit to a thin film transistor substrate according to another aspect of the present invention is as follows.

First, anisotropic particles contained in the anisotropic conductive film are attached to one of the data pads or gate pads of the thin film transistor substrate. Next, the driving integrated circuit is attached to one of the data pad or gate pad to which the anisotropic particles are attached through the alignment key. The attachment state of the driving integrated circuit is inspected and the electrical evaluation is performed to determine whether there is any defect. In the event of a failure, the driver integrated circuit is removed from either the data pad or gate pad to which the anisotropic particles are attached. Next, anisotropic particles contained in the anisotropic conductive film are attached to the other side of the data pad or the gate pad. The driving integrated circuit is attached to the other side of the data pad or gate pad to which the anisotropic particles are attached through the alignment key. The attachment state of the driving integrated circuit is inspected and the electrical evaluation is performed to determine whether it is defective, and then the attachment of the driving integrated circuit is completed.

Next, the thin film transistor substrate according to the embodiment of the present invention will be described in detail with reference to the accompanying drawings so that a person skilled in the art can easily implement the present invention.

FIG. 1 is a layout view of a thin film transistor substrate for a liquid crystal display according to a first exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line II-II 'of FIG. 1.

1 and 2, the gate line 21 extending in the horizontal direction on the insulating substrate 10, the gate electrode 22 which is a part of the gate line 21, and the end of the gate line 21 are connected to each other. Gate wirings including first and second gate pads 23 and 24 that receive scan signals and transmit the scan signals to the gate lines 21 are formed.

The gate wirings 21, 22, 23, and 24 are covered with a gate insulating film 30 made of silicon nitride (SiN _X ).

A semiconductor layer 41 made of a semiconductor such as amorphous silicon is formed on the gate insulating film 30, and a resistivity made of a semiconductor such as amorphous silicon doped with n-type impurities such as phosphorus (P) is formed on the semiconductor layer 41. The contact layers 51 and 52 are separated and formed at both sides with respect to the gate electrode 22.

On the ohmic contacts 51 and 52, the data line 61 extending in the vertical direction, the source electrode 62 which is a part of the data line 61, and the drain facing the source electrode 62 around the gate electrode 22. A data line including first and second data pads 65 and 66 connected to the electrode 63 and the data line 61 to receive an image signal from the outside and to transmit the image signal to the data line 61 is formed.

Here, the gate electrode 22, the semiconductor layer 41, the source electrode 62, and the drain electrode 63 form a thin film transistor.

A protective film 70 made of silicon nitride or an organic insulating film is formed on the data wires 61, 62, 63, 65, 66. The passivation layer 70 has contact holes 73 and 74 exposing the gate pads 23 and 24 together with the gate insulating film 30, as well as contact holes 75 and 76 exposing the data pads 65 and 66. And a contact hole 72 exposing the drain electrode 63.

The pixel electrode 80, the first and second auxiliary gate pads 83 and 84, and the first and second auxiliary layers formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) are disposed on the passivation layer 70. Data pads 85 and 86 are formed.

The pixel electrode 80 is connected to the drain electrode 63 through the contact hole 72 to receive an image signal. The auxiliary gate pads 83 and 84 and the auxiliary data pads 85 and 86 are connected to the gate pads 23 and 24 and the data pads 65 and 66 through the contact holes 73, 74, 75 and 76, respectively. In addition, they complement the adhesion between the pads 23, 24, 65 and 66 and the external circuit device and serve to protect the pads 23, 24, 65 and 66.

Next, the reason for forming the gate pad and the data pad in duplicate, respectively, will be described with reference to FIGS. 3 to 6.

First, a method of electrically connecting a driving integrated circuit to a pad part by applying a COG mounting method to a thin film transistor substrate having multiple pads according to a first embodiment of the present invention will be described.

FIG. 3 is a view illustrating a state in which an anisotropic conductive film is attached to a first auxiliary data pad to attach a driving integrated circuit, and FIG. 4 is a cross-sectional view taken along line IV-IV ′ of FIG. 3. Is a view showing a state attached. FIG. 5 is a view illustrating a state in which an anisotropic conductive film is attached to a second auxiliary data pad to attach a driving integrated circuit, and FIG. 6 is a cross-sectional view taken along line VI-VI ′ of FIG. 5. Is a view showing a state attached.

In the COG mounting method, the driving integrated circuit is directly connected to the pad of the thin film transistor substrate by using an anisotropic conductive film. An anisotropic conductive film containing conductive particles is attached on the glass substrate on which the auxiliary pad is formed, and on top of it. Compress the driving integrated circuit.

More specifically, as shown in FIG. 3, an anisotropic conductive film containing conductive particles is attached to the first auxiliary data pad 85 of the completed thin film transistor substrate shown in FIGS. 1 and 2. Here, the conductive particles are included in the anisotropic conductive film, and are conductive materials that electrically connect the pad portion of the thin film transistor and the driving integrated circuit in the vertical direction to allow a signal of the driving integrated circuit to flow to the pad portion.

Next, as shown in FIG. 4, the driving integrated circuit is attached to the upper portion of the first auxiliary data pad 85 to which the anisotropic particles are attached. At this time, the bumps protruding from the driving integrated circuit are bonded to the compressed anisotropic particles.

Subsequently, the attachment state of the driving integrated circuit is inspected and the electrical evaluation is performed to determine whether there is a poor contact between the first auxiliary data pad and the driving integrated circuit, and if there is no defect, the attachment process of the driving integrated circuit is completed.

However, if it is determined that the attachment state of the driving integrated circuit is bad, the driving integrated circuit is detached from the first auxiliary data pad. In this case, the anisotropic conductive particles may remain in the first auxiliary data pad 85 without being completely removed, and thus it is difficult to attach the driving integrated circuit to the upper part of the first auxiliary data pad 85.

Next, as shown in FIG. 5, an anisotropic conductive film including conductive particles is attached to the second auxiliary data pad 85.

Next, as shown in FIG. 6, the driving integrated circuit is attached to the second auxiliary data pad 85 to which the anisotropic particles are attached. At this time, the bumps protruding from the driving integrated circuit are bonded to the compressed anisotropic particles.

 The attachment state of the driving integrated circuit is inspected and the electrical evaluation is performed to determine whether there is a poor contact between the second auxiliary data pad and the driving integrated circuit, and if there is no defect, the attachment process of the driving integrated circuit is completed.

 The process of attaching the driving integrated circuit to the thin film transistor substrate according to the first exemplary embodiment of the present invention has been described only with respect to the auxiliary data pads 85 and 86, but the same method may be performed with the auxiliary gate pads 83 and 84. have.

In addition, in the first embodiment of the present invention, two pads may be formed, but two or more pads may be formed.

In the process of attaching the driving integrated circuit according to the present invention, the anisotropic conductive particles are adhered to the first auxiliary pad as shown in FIG. 3 at the first operation, and the driving integrated circuit is detached when rework is necessary. Next, as shown in FIG. 5, the driving integrated circuit is attached using the second auxiliary pad. Therefore, in the present invention, the rework is possible by improving the conventional problem that the rework cannot be performed in the process of attaching the driving integrated circuit, and thus the process yield can be improved.

Meanwhile, the first embodiment described above has described thin film transistors in which two or more pads are formed so as to rework the process of attaching the driving integrated circuit to the pad portion. The process of attaching the circuit can be reworked, which will be described in detail with reference to the drawings.

FIG. 7 is a layout view of a thin film transistor substrate for a liquid crystal display according to a second exemplary embodiment of the present invention, and FIG. 8 is a cross-sectional view taken along the line VIII-VIII ′ of FIG. 7.

All structures except the pad portion are the same as in the first embodiment. However, in the second embodiment of the present invention, each pad connected to each of the wirings is formed at least twice as long as the bump length of the driving integrated circuit.                     

Therefore, when attaching the driving integrated circuit to the pad, the driving integrated circuit is attached to one portion of the pad formed long during the first operation through the anisotropic conductive film. The rework of attaching the driving integrated circuit through the anisotropic conductive film on one side was made possible. The process of attaching the driving integrated circuit to each other portion of the elongated pad allows the driving integrated circuit to be accurately attached to the corresponding position through an alignment key.

As in the first and second embodiments of the present invention, two or more pads may be formed, or the length of the pad may be longer than twice the bump of the driving integrated circuit to enable reworking. Various changes and implementations can be made without departing from the scope of the claims set out.

As described above, in the present invention, even when an operation error or a defect of the driving integrated circuit occurs when the driving integrated circuit is attached by the COG mounting method, the work can be reworked without removing the anisotropic conductive particles during the first operation. Yield can be improved.

Claims (4)

A gate line formed over the insulating substrate, A gate pad connected to an end of the gate line to receive a gate signal from the outside and transmit the gate signal to the gate line; A data line insulated from and intersecting the gate line to define a pixel area; A data pad connected to an end of the data line to receive a data signal from an external source and to transmit the data signal to the data line; A thin film transistor connected to the gate line and the data line, A pixel electrode formed in the pixel region and connected to the gate line and the data line through the thin film transistor Including, And at least two gate pads or data pads on one gate line or one data line. A gate line formed over the insulating substrate, A gate pad connected to an end of the gate line to receive a gate signal from an external driving integrated circuit; A data line insulated from and intersecting the gate line to define a pixel area; A data pad connected to an end of the data line to receive a data signal from an external driving integrated circuit; A thin film transistor connected to the gate line and the data line, A pixel electrode formed in the pixel region and connected to the gate line and the data line through the thin film transistor The thin film transistor substrate of claim 1, wherein the gate pad or the data pad is at least twice as long as the length of the driving integrated circuit bump. The method of attaching a driving integrated circuit to the thin film transistor substrate of claim 1, Attaching anisotropic particles included in an anisotropic conductive film to a first data pad or a first gate pad of the thin film transistor substrate, Attaching the driving integrated circuit to the first data pad or first gate pad to which the anisotropic particles are attached; Inspecting the attachment state of the driving integrated circuit and performing an electrical evaluation to determine whether there is a defect; Detaching the driving integrated circuit from the first data pad or the first gate pad to which the anisotropic particles are attached when a failure occurs; Attaching anisotropic particles included in an anisotropic conductive film to a second data pad or a second gate pad of the thin film transistor substrate, Attaching the driving integrated circuit to the second data pad or second gate pad to which the anisotropic particles are attached; Checking the attachment state of the driving integrated circuit and performing an electrical evaluation to determine whether the driving integrated circuit is defective, and then completing the attachment of the driving integrated circuit. Method for attaching a driving integrated circuit of a thin film transistor substrate comprising a. The method of attaching a driving integrated circuit to the thin film transistor substrate of claim 2, Attaching anisotropic particles contained in the anisotropic conductive film to one of the data pads or the gate pads of the thin film transistor substrate, Attaching the driving integrated circuit to one of the data pad or gate pad to which the anisotropic particles are attached through an alignment key; Inspecting the attachment state of the driving integrated circuit and performing an electrical evaluation to determine whether there is a defect; Removing the driving integrated circuit from one of the data pad or gate pad to which the anisotropic particle is attached when a failure occurs; Attaching anisotropic particles contained in the anisotropic conductive film to the other side of the data pad or gate pad, Attaching the driving integrated circuit to the other side of the data pad or gate pad to which the anisotropic particles are attached through an alignment key; Checking the attachment state of the driving integrated circuit and performing an electrical evaluation to determine whether the driving integrated circuit is defective, and then completing the attachment of the driving integrated circuit. Method for attaching a driving integrated circuit of a thin film transistor substrate comprising a.

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