JPH05303107A - Manufacture of liquid crystal display device - Google Patents

Abstract

PURPOSE:To make electromechanical connections between output terminals of a driver IC and external lead-out electrodes of a liquid crystal panel by forming adhesion assisting layers after curing reaction at both side parts across the lead-out electrodes. CONSTITUTION:The insulating adhesion assisting layers 5 are formed across the lead-out electrodes 4, formed on a liquid crystal panel substrate 2, to the same width as the gap width between the lead-out electrodes 4. Then an anisotropic conductive film 6 is stuck on the surface of a liquid crystal panel base material 2 where a TAB driver IC is connected, and an IC output terminal 3 formed on a TAB driver IC base material 1 is positioned just above the lead-out electrodes 4. Then a pressing tool which is heated is pressed to put the lead-out electrodes 4 and IC output terminals 3 closer up to a distance of about 1mum and while the electromechanical connections are made with conductive particles 7 present between the lead-out electrodes 4 and IC output terminals 3, the curing reaction of the anisotropic conductive film 6 is caused to arrange and adhere the IC driver terminals 3 between the adhesion assisting layers 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a liquid crystal display device, and more particularly to a method of manufacturing a liquid crystal display device including a step of connecting a liquid crystal panel and a TAB driver IC for driving the liquid crystal panel.

[0002]

2. Description of the Related Art Conventionally, when a TAB driver IC for driving is connected to a liquid crystal panel, thermocompression bonding using an anisotropic conductive film is known.

In this thermocompression bonding method, as shown in FIG. 2A, for example, ITO formed on the liquid crystal panel substrate 2 is used.
An anisotropic conductive film 6 is adhered on the external extraction electrode 4 made of a film, and then, for example, TAB made of a polyimide material.
The external extraction electrode 4 of the liquid crystal panel is provided on the driver IC substrate 1.
TA having IC output terminals 3 formed at the same pitch as
By aligning the B driver IC and pressing the heated crimping tool onto the TAB driver IC base material 1 at the portion to be connected to the TAB driver IC, the liquid crystal panel is pulled out to the outside as shown in FIG. 2 (B). The electrode 4 and the IC output terminal 3 of the TAB driver IC are opposed to each other by a distance of about 1 μm, and electrically conductive by the conductive particles 7 in the anisotropic conductive film 6 sandwiched between the external extraction electrode 4 and the IC output terminal 3. While conducting electricity, a curing reaction of the adhesive portion of the anisotropic conductive film 6 is caused to obtain mechanical adhesion.

[0004]

In the case of the above-mentioned conventional thermocompression bonding method, as the TAB driver IC substrate 1, generally,
A polyimide material having a thickness of 50 μm to 125 μm is used, while glass is used as the liquid crystal panel substrate 2, and the coefficient of thermal expansion of the former exceeds that of the latter by one digit or more. In an environment where the TAB driver IC base material 1 and the liquid crystal panel base material 2 expand and contract repeatedly under a changing environment, shear stress is generated in the anisotropic conductive film 6, and the IC output terminal 3 of the driver IC and the liquid crystal panel are pulled out. The conductive particles 7 that contribute to electrical conduction with the electrode 4 move or float at the connection interface, leading to an increase in connection resistance, and in the worst case, connection peeling.
There is a problem that it is difficult to obtain a stable connection.

An object of the present invention is to provide a method of manufacturing a liquid crystal display device in which a stable connection can be obtained between the IC output terminal of the driver IC and the external lead electrode of the liquid crystal panel.

[0006]

According to the present invention, an external extraction electrode formed on a liquid crystal panel base material and an IC output terminal formed on a TAB driver IC base material are heated via an anisotropic conductive film. TAB driver IC for driving to liquid crystal panel by pressure bonding
In the method for manufacturing a liquid crystal display device having a step of connecting to each other, a connection auxiliary layer is provided on the liquid crystal panel base material with the external extraction electrode sandwiched therebetween, and the external extraction electrode and the IC output terminal are aligned with each other. The method includes a step of connecting the driving TAB driver IC to the liquid crystal panel by thermocompression bonding via a anisotropic conductive film.

[0007]

The TAB driver IC base material expands and contracts due to changes in ambient temperature by preliminarily forming an adhesive auxiliary layer that has completed a sufficient curing reaction on both sides of the liquid crystal panel with the external extraction electrode sandwiched between them. Even if shear stress is generated in the conductive conductive film, each side wall of the adhesion auxiliary layer and the TAB driver IC
The expansion and contraction of the TAB driver IC base material is suppressed by the opposite stress generated on the side wall of each IC output terminal. Therefore, the shearing force does not act directly on the connection interface between the external extraction electrode of the liquid crystal panel and the conductive particles sandwiched between the IC output terminals of the TAB driver IC, and stable electrical connection can be obtained.

[0008]

Embodiments of the present invention will now be described with reference to the drawings.

FIGS. 1A and 1B are cross-sectional views showing a process sequence for explaining an embodiment of the present invention.

First, as shown in FIG. 1A, ITO having a thickness of several hundred angstroms is formed on a liquid crystal panel substrate 2.
A thickness of 10 μm to 40 with a width equivalent to the gap width between the external extraction electrodes 4 with the external extraction electrodes 4 formed of a film interposed therebetween.
An insulating adhesion auxiliary layer 5 having a thickness of μm is formed. Next, on the surface of the liquid crystal panel substrate 2 including the external extraction electrode 4 and the adhesion auxiliary layer 5 to which the TAB driver IC is to be connected, 10 μm to 30 μm.
An anisotropic conductive film 6 having a thickness of μm is attached.

Then, as shown in FIG. 1B, TA
After aligning the IC output terminal 3 formed on the B driver IC substrate 1 with a thickness of 20 μm to 50 μm so as to be directly above the external extraction electrode 4 on the liquid crystal panel substrate 2, 2
Press the crimping tool heated to 00 ℃ to 300 ℃,
The distance between the external extraction electrode 4 and the IC output terminal 3 which face each other is made close to about 1 μm, and electrical connection is obtained by the conductive particles 7 existing between the external extraction electrode 4 and the IC output terminal 3, and at the same time, anisotropy is obtained. The IC output terminal 3 of the TAB driver thermocompression bonded by causing a curing reaction in the conductive film 6.
Are arranged and bonded in such a manner that they are sandwiched between the adhesion auxiliary layers 5 formed on the liquid crystal panel base material 2.

[0012]

As described above, according to the present invention, the adhesion auxiliary layer 5 is formed so as to sandwich the external extraction electrode 4 of the liquid crystal panel, and the IC output terminal 3 of the TAB driver IC is sandwiched by the adhesion auxiliary layer 5. Since the TAB driver IC base material 1 expands and contracts due to changes in ambient temperature,
Expansion and contraction are suppressed by the opposite stress generated in the side wall portions of the IC output terminal side wall portion 8 and the adhesion auxiliary layer side wall portion 9 of the TAB driver IC, and the generation of stress at the interface of the conductive particles 7 that contributes to electrical conduction is reduced. Accordingly, it is possible to increase the electric resistance of the connection portion between the IC output terminal 3 of the driver IC and the external lead electrode 4 of the liquid crystal panel or prevent the connection from peeling off, and to obtain a stable connection and improve the connection reliability.

[Brief description of drawings]

1A to 1D are cross-sectional views showing a process sequence for explaining an embodiment of the present invention.

2A to 2D are cross-sectional views showing an example of a method of manufacturing a conventional liquid crystal display device in order of steps.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 TAB driver IC base material 2 Liquid crystal panel base material 3 IC output terminal 4 External extraction electrode 5 Adhesion auxiliary layer 6 Anisotropic conductive film 7 Conductive particles 8 IC output terminal side wall portion 9 Adhesion auxiliary layer side wall portion

Claims (1)

[Claims] 1. A driving TAB on a liquid crystal panel by thermocompression bonding an external extraction electrode formed on a liquid crystal panel base material and an IC output terminal formed on a TAB driver IC base material via an anisotropic conductive film. In a method of manufacturing a liquid crystal display device including a step of connecting a driver IC, a connection auxiliary layer is provided on the liquid crystal panel base material with the external extraction electrode interposed therebetween, and the external extraction electrode and the IC output terminal are aligned with each other. A method of manufacturing a liquid crystal display device, comprising a step of connecting the driving TAB driver IC to the liquid crystal panel by thermocompression bonding via the anisotropic conductive film.