JP2005077980A - Manufacturing method of liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a liquid crystal display by which thermal damage in peripheral members is eliminated, infiltration of moisture into an anisotropic conductive film and corrosion of a panel electrode are prevented by efficiently curing the anisotropic conductive film on the periphery of a driving IC to be a semiconductor element and reduction of display quality can be prevented. <P>SOLUTION: In the manufacturing method of the liquid crystal display wherein the semiconductor element is thermocompression-bonded to a plurality of terminal electrodes for connection arranged at a terminal part of a transparent insulation substrate on which pixel electrodes for display are provided via the anisotropic conductive film, when the semiconductor element is thermocompression bonded by using a first heater tool, heating is performed by using a second heater tool from the surface opposite to the semiconductor element compressed surface of the transparent insulation substrate to cure the anisotropic conductive film on the periphery of the semiconductor element. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a liquid crystal display device. More specifically, the present invention relates to a manufacturing method of a COG (chip on glass) mounting type liquid crystal display device in which a liquid crystal is sandwiched between two transparent insulating substrates and a driving IC is directly mounted on one substrate.

  Liquid crystal display devices are widely used as monitors for personal computers, portable terminals, televisions and the like as thin, lightweight, and low power consumption display devices. This liquid crystal display device is configured to overlap a lighting device after connecting a drive circuit to a liquid crystal sandwiched between two transparent insulating substrates (glass substrates). For example, in a liquid crystal display device using a thin film transistor (hereinafter simply referred to as a TFT), of two glass substrates, a TFT substrate in which TFTs are arranged in a matrix and a color filter (CF) substrate, the TFT substrate is more than the CF substrate. The outer shapes are stacked on top of each other. One pixel is formed in each TFT, and an image signal sent to the pixel is controlled by turning the TFT on / off. Source wiring for inputting an image signal from the source electrode of each TFT is drawn out in parallel with the short side of the glass substrate, and a pad for connecting a drive circuit is formed near the end on the long side of the TFT substrate. Yes. Also, a gate wiring for turning on / off the TFT is drawn out from the gate electrode of each TFT in parallel with the long side of the TFT substrate, and the drive circuit is connected in the vicinity of the end on the short side of the TFT substrate in the same manner as the source side. A pad is formed for the purpose.

  A configuration of a small TFT liquid crystal display device in which a drive circuit is mounted by a COG mounting method will be described with reference to FIGS. A liquid crystal (not shown) is sandwiched between the TFT substrate 101 and the CF substrate 102. A wiring (display pixel electrode) 103 for supplying a signal to the pixel is formed on the TFT substrate 101, and is anisotropic to the panel electrode 103a disposed on the protruding portion of the TFT substrate 101 at the end of the panel. The driving IC 105 is directly mounted by sandwiching a conductive fine particle dispersed in an adhesive resin called an ACF (Anisotropic Conductive Flilm) 104 and thermocompression bonding. The anisotropic conductive film 104 is generally in the form of a film. After the film-like anisotropic conductive film is attached to the panel electrode portion, the drive IC 105 is positioned on the panel electrode 103a, and the drive IC 105 Joining by pressing the heater tool from above. A signal for controlling the driving IC 105 is formed by forming a panel electrode 103a at the end of the wiring 103 arranged around the driving IC 105 of the TFT substrate 101, and flexibly passing through the anisotropic conductive film 104 to the panel electrode 103a. Input is made by connecting a printed circuit board (FPC) 106. A moisture-proof resin 107 is applied to the periphery of the connection portion between the driving IC 105 and the flexible printed circuit board 106 in order to prevent corrosion of the panel electrode 103a of the wiring 3. 3 to 4, reference numerals 108 and 109 denote TFT side polarizing plates and CF side polarizing plates.

  Incidentally, a thermosetting epoxy resin is generally used as the resin for the anisotropic conductive film, and this resin contains a small amount of impurity ions such as chlorine ions. When moisture enters the epoxy resin, it reacts with the material of the panel electrode when voltage is applied, and the panel electrode is eroded. In addition, the moisture permeability of the anisotropic conductive resin varies greatly depending on the curing reaction rate, and the uncured resin has a moisture permeability that is about 3 to 10 times higher than that of the cured resin, making it easy to pass moisture. . The COG mounting method is generally a method in which a heater tool is pressed over the drive IC to cure the resin of the anisotropic conductive film, but in this method, the anisotropic conductive resin directly under the drive IC is cured. However, since the anisotropic conductive film around the drive IC is not cured, the anisotropic conductive film around the drive IC easily passes moisture, and the impurity ions in the anisotropic conductive film easily move, and the periphery of the drive IC. The panel electrode is likely to corrode in the area. In order to prevent this terminal corrosion, conventionally, a moisture-proof resin is applied to the periphery of the connection portion of the drive IC and the flexible printed circuit board. As the moisture-proof resin, a silicone resin, an acrylic resin, a urethane resin, a fluorine resin, or the like is used. However, since these moisture-proof resins also pass a certain amount of moisture, moisture penetrates into the anisotropic conductive film in the periphery of the drive IC, which is insufficient as a countermeasure against terminal corrosion. In addition, the size of the anisotropic conductive film to be attached to the panel electrode part is made as small as possible, the anisotropic conductive film existing outside the outer shape of the drive IC is reduced as much as possible, and it is attached when the drive IC is thermocompression bonded. Although attempts have been made to cure all of the anisotropic conductive film, it is necessary to paste an anisotropic conductive film that is somewhat larger than the driving IC in terms of the outer shape accuracy and pasting accuracy of the anisotropic conductive film. Therefore, it is difficult to cure the entire anisotropic conductive film, and there is a problem that an uncured portion remains.

  Therefore, a method has been proposed in which the anisotropic conductive film is hardened by aging the entire panel after the drive IC is pressure-bonded (see, for example, Patent Document 1). However, due to heat resistance limitations, there is a problem that the treatment cannot be performed with the polarizing plate attached, and there is a thermal damage to the liquid crystal. In addition, the temperature reached by the anisotropic conductive film directly under the driving IC at the time of thermocompression bonding is about 170 to 230 ° C., whereas the aging treatment is about 150 ° C. due to the heat resistance restriction of other members. There is a problem that the curing reaction rate of the conductive film is low and the processing time is long.

JP 2003-161956 A

  In view of the above circumstances, the present invention has no thermal damage to peripheral members, and efficiently cures the anisotropic conductive film in the periphery of the drive IC that is a semiconductor element. An object of the present invention is to provide a method for producing a liquid crystal display device capable of preventing moisture from entering the panel and corroding panel electrodes and preventing deterioration in display quality.

  According to the method for manufacturing a liquid crystal display device of the present invention, a semiconductor element is thermocompression bonded to a plurality of connection terminal electrodes arranged at an end of a transparent insulating substrate provided with a display pixel electrode through an anisotropic conductive film. A method of manufacturing a liquid crystal display device, wherein when the semiconductor element is subjected to thermocompression bonding with a first heater tool, heating is performed by a second heater tool from a surface opposite to the crimping surface of the semiconductor element of the transparent insulating substrate. The anisotropic conductive film in the peripheral portion of the semiconductor element is cured.

  According to the present invention, the anisotropic conductive film is heated by the second heater tool from the back surface of the substrate on which the panel electrode is provided during thermocompression bonding of the drive IC, and the anisotropic conductive film in the periphery of the drive IC is cured. As a result, it is possible to improve the reliability of the liquid crystal display device by preventing moisture permeation into the anisotropic conductive film and corrosion of the panel electrode, and preventing deterioration in display quality.

Hereinafter, a method for manufacturing a liquid crystal display device according to the present invention will be described with reference to the accompanying drawings.
1 and 2 are diagrams for explaining a method of manufacturing a liquid crystal display device according to an embodiment of the present invention. FIG. 1 is a diagram seen from the front side of a panel electrode array, and FIG. It is the figure seen from the side.

  As shown in FIGS. 1 and 2, a TFT substrate 1, which is a transparent insulating substrate, and a color filter (CF) substrate 2 are overlaid, and a liquid crystal panel (not shown) is sealed between the two substrates. Make it. A wiring (display pixel electrode) 3 is formed on the TFT substrate 1. An anisotropic conductive film 4 is attached on the wiring 3 and a driving IC 5 which is a semiconductor element is positioned. A TFT-side polarizing plate 6 and a CF-side polarizing plate 7 are pasted slightly inside the region where the TFT substrate 1 and the CF substrate 2 overlap. As the anisotropic conductive film 4, for example, a thermosetting epoxy resin can be used.

  Next, the heater IC 8 for heating and pressurizing the driving IC, which is the first heater tool, is pressed onto the driving IC 5 arranged on the plurality of connection terminal electrodes (panel electrodes) 3a arranged at the end of the TFT substrate 1. Then, the driving IC 5 is heated and pressurized. Further, the second heater tool 9 for heating the TFT substrate back surface, which is disposed on the back surface side of the protruding portion of the TFT substrate 1 at the time of thermocompression bonding, is pressed to heat the entire anisotropic conductive film 4 to a high temperature. As the second heater tool 9 on the back side of the substrate, one having a larger area than the outer shape of the anisotropic conductive film 4 attached to the panel electrode 3 a formed at the end of the wiring 3 is used. Further, the heating position is a region (projected portion) of the substrate 1 outside the region where the liquid crystal is sandwiched between the two substrates 1 and 2, and is a region where the polarizing plate 6 is not attached. .

  Next, a flexible printed circuit board (not shown) is connected to the panel electrode 3a through an anisotropic conductive film 5.

  Next, a moisture-proof resin (not shown) is applied around the connection portion between the drive IC 4 and the flexible printed board so as to cover the entire anisotropic conductive film 4 in order to prevent corrosion of the panel electrode 3 a at the end of the wiring 3. . As the moisture-proof resin, for example, a silicone resin, an acrylic resin, a urethane resin, or a fluorine resin can be used.

  In the present embodiment, when the driving IC 5 is thermocompression bonded with the first heater tool, the region L of the anisotropic conductive film 4 that does not overlap with the driving IC 5 due to the heating of the second heater tool 9 is different from the region immediately below the driving IC 5. The isotropic conductive film 4 is cured at the same time. Since the second heater tool 9 on the back surface side of the TFT substrate 1 is disposed at a position that does not overlap the TFT side polarizing plate 6 and the CF side polarizing plate 7, the polarizing plate 6 is compared with the case where the entire panel is aged. , 7 is difficult to transmit heat, and damage to the polarizing plates 6, 7 can be prevented. Further, since the region L of the anisotropic conductive film 4 in the peripheral portion of the drive IC 5 is cured at the same time as the main compression bonding of the drive IC 5, the number of curing processing steps does not increase.

  Further, the heating is a distance away from the region in which the liquid crystal is sealed, and does not affect the liquid crystal, so that the display quality is not affected. Therefore, it is possible to heat the anisotropic conductive film 4 around the drive IC 5 at a high temperature. For example, the temperature of the anisotropic conductive film 4 in the periphery of the drive IC 5 can be heated to 170 to 200 ° C., which is about the same as that immediately below the drive IC. Thereby, the anisotropic conductive film 4 in the peripheral portion of the drive IC 5 can increase the curing reaction rate to the same extent as that directly below the drive IC.

  Further, since the underlying anisotropic conductive film 4 is sufficiently cured by the heating of the second heater tool 9 and the moisture permeability is very small as compared with the uncured state, even if the moisture-proof resin transmits moisture to some extent. Even then, corrosion by impurity ions in the anisotropic conductive film can be prevented.

It is a figure explaining the manufacturing method of the liquid crystal display device concerning one embodiment of this invention. It is a fragmentary sectional view explaining the manufacturing method of the liquid crystal display device concerning one embodiment of this invention. It is a side view which shows an example of the conventional liquid crystal display device. FIG. 4 is a perspective view of the liquid crystal display device of FIG. 3.

Explanation of symbols

1 TFT substrate 2 Color filter (CF) substrate 3 Wiring 4 Anisotropic conductive film 5 Drive IC
6 TFT side polarizing plate 7 CF side polarizing plate 8 Heater tool for driving IC heating and pressurization 9 Second heater tool for heating the back surface of the TFT substrate

Claims (1)

A method of manufacturing a liquid crystal display device in which a semiconductor element is thermocompression bonded to a plurality of connection terminal electrodes arranged at end portions of a transparent insulating substrate provided with a display pixel electrode through an anisotropic conductive film, When the semiconductor element is subjected to thermocompression bonding with the first heater tool, the second heater tool is used to heat the surface of the transparent insulating substrate opposite to the semiconductor element crimping surface, so that the peripheral portion of the semiconductor element is different. A method for producing a liquid crystal display device, comprising curing a isotropic conductive film.

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