JP4650050B2 - Method for electrically installing electronic parts and method for manufacturing liquid crystal display elements - Google Patents

Description

The present invention relates to a conduction installation method for an electronic component and a method for manufacturing a liquid crystal display element .

  Conventionally, for example, in a liquid crystal display element, when a liquid crystal driving LSI chip and a flexible wiring substrate for supplying signal voltage are electrically connected to the end of a glass substrate on which a lead wiring pattern led out from each electrode is formed, Conductive adhesive is used.

In this case, since the LSI chip and the flexible wiring board usually have different connecting terminal pitches, an anisotropic conductive adhesive suitable for each connecting terminal pitch is used. Therefore, as shown in Patent Document 1, anisotropic conductive adhesives are individually arranged on the LSI chip and the flexible wiring board.
JP 2002-244151 A

  However, when a separate anisotropic conductive adhesive is disposed for each electronic component to be mounted, the anisotropic conductive adhesive is disposed by performing the alignment step by step in each component mounting step, and therefore the number of manufacturing steps is reduced. I will increase that much. In addition, since it is necessary to allow for the placement error and the extension allowance during thermocompression bonding for each anisotropic conductive adhesive, the total space for placing multiple anisotropic conductive adhesives becomes large, and the size of the applied product becomes small. It is disadvantageous for conversion. In particular, in the case of a liquid crystal display element used as a display of a portable terminal device, the demand for miniaturization and thinning is extremely severe, and it has been strongly demanded to reduce the arrangement space of the anisotropic conductive adhesive.

An object of the present invention, an electronic component number of steps required for conducting the installation of the electronic components with the arrangement space of the anisotropic conductive adhesive is reduced is greatly reduced, size and cost of application products is remarkably promoted It is providing the conduction | electrical_connection installation method of this, and the manufacturing method of a liquid crystal display element .

According to the electrical component conduction installation method of the present invention, the first electronic component and the second electronic component are installed in a predetermined installation region on a circuit board on which a wiring pattern is formed via an anisotropic conductive adhesive sheet. An electronic component conducting installation method comprising: a cradle having a support surface having a larger area than the installation area; and at least an entire area corresponding to the installation area of the lower surface of the circuit board contacts the support surface. The circuit board is placed so as to be in the first state, and the anisotropic conductive adhesive sheet in the form of a single film is placed on the installation area on the circuit board and the anisotropic conductive film is placed. A first step of placing the first electronic component in a first region on the adhesive sheet, and heating the first electronic component in the first state after the first step The first electric power is applied by applying pressure to the circuit board. A second step of conducting installation parts, the later than the second step, the anisotropic conductive placed in the second region on the adhesive sheet was the second electronic component while heating said circuit And a third step of conducting and installing the second electronic component by pressurizing the substrate toward the substrate.

The method for manufacturing a liquid crystal display element according to the present invention includes a predetermined installation area on a first substrate on which a wiring pattern is formed between an LSI chip for driving liquid crystal and a flexible wiring substrate for supplying a signal voltage to the LSI chip. The liquid crystal display element is installed through an anisotropic conductive adhesive sheet on a cradle having a support surface having a larger area than the installation region, and at least the lower surface of the first substrate The first substrate is placed so that the entire region corresponding to the installation region is in a first state in contact with the support surface, and one film is formed in the installation region on the first substrate. A first step of placing the anisotropic conductive adhesive sheet and placing the LSI chip in a first region on the anisotropic conductive adhesive sheet, and after the first step, Add the LSI chip in the first state A second step of installing conduct the LSI chip by pressing toward the first substrate while, later than the second step, the second area on the anisotropic conductive adhesive sheet And a third step of conducting and installing the flexible wiring board by applying pressure to the circuit board while heating the mounted flexible wiring board.

According to the present invention, the arrangement space for the anisotropic conductive adhesive is reduced and the number of man-hours required for the conductive installation of the electronic component is greatly reduced, and the downsizing and cost reduction of the applied product can be significantly promoted. .

  FIG. 1 is a plan view showing a liquid crystal display device according to an embodiment of the present invention, and FIG. 2 is a schematic partial cross-sectional view showing a main part cut along a line II-II.

  In the liquid crystal display element of this embodiment, as shown in FIG. 1, a pair of glass substrates 1 and 2 having a rectangular planar outer shape are joined together with a frame-shaped sealing material 3 with a predetermined gap. The pair of glass substrates 1 and 2 are different in size, and one long side end 1a of the larger glass substrate 1 is protruded from the corresponding end surface of the other small glass substrate 2 by an appropriate length. Are joined.

  As shown in FIG. 2, electrodes 4 and 5 are disposed on the opposing surfaces (inner surfaces) of the pair of glass substrates 1 and 2, respectively, and a frame between the pair of glass substrates 1 and 2. Liquid crystal 6 is sealed in the space surrounded by the sealing material 3. A region where the electrodes 4 and 5 are opposed to each other with the liquid crystal 6 is a pixel, and the plurality of pixels are arranged in a predetermined arrangement to form a display region Dd (see FIG. 1).

  On the protruding portion 1a of the large glass substrate 1, lead wirings 7 and 8 led out from the electrodes 4 and 5 of the glass substrates 1 and 2 are arranged in a predetermined pattern.

  Then, one driver chip 9 that supplies a signal voltage to each of the electrodes 4 and 5 to drive the liquid crystal, and a flexible wiring board 10 for inputting the signal voltage to the driver chip 9 are respectively provided at predetermined positions on the protruding portion 1a. Conductive installation.

  The driver chip 9 and the flexible wiring board 10 are one piece of anisotropic conductive material having a size covering the connection area of the driver chip 9 and the connection area of the flexible wiring board 10 in the protruding portion 1 a of the large glass substrate 1. The lead wires 7 and 8 and the input wires 12 are conductively connected by the adhesive 11. The anisotropic conductive adhesive 11 is formed into a film by dispersing and mixing the conductive particles 11b in the insulating resin substrate 11a. In this embodiment, a thermosetting epoxy resin is used as the insulating resin substrate 11a. In addition, conductive particles 11b formed by coating the surfaces of the resin particles with a nickel film are dispersed and mixed.

  In the driver chip 9, a plurality of terminal electrodes 9a are arranged at a pitch of 20 μm on the bottom surface of the chip body. These terminal electrodes 9 a are provided in a staggered manner on the input side and output side of the driver chip 9.

  The flexible wiring board 10 has a plurality of striped wirings 10b made of copper foil arranged in parallel at a pitch of 200 μm on the surface of a base sheet 10a made of a polyimide resin film or the like. The formed connection terminal portions (not shown) are also juxtaposed at a pitch of 200 μm.

  Here, in the present invention, as the anisotropic conductive adhesive 11 described above, the average particle diameter of the conductive particles 11b is 1/4 or less of the pitch of the terminal electrodes 9a in the driver chip 9, and preferably 1 / Those prepared in 5 or less are used. In the present embodiment, the anisotropic conductive adhesive 11 in which the average particle diameter of the conductive particles 11b is 4 μm is used for the driver chip 9 in which the pitch of the terminal electrodes 9a is 20 μm.

  By using the anisotropic conductive adhesive 11 described above, an appropriate conductive connection structure can be obtained in both the driver chip 9 and the flexible wiring board 10. That is, although the pitch of the terminal electrodes 9a in the driver chip 9 is as small as 20 μm, the average particle diameter of the conductive particles 11b of the anisotropic conductive adhesive 11 is sufficiently small as 4 μm, which is 1/5, so that the adjacent terminal electrodes 9a Insulation between them is sufficiently ensured, and each terminal electrode 9a and the corresponding lead wiring connection terminal are securely conductively connected. In addition, since the pitch of the wiring 10b in the flexible wiring board 10 is 200 μm and the width of each wiring is 100 μm, both of which are sufficiently larger than the average particle diameter of the conductive particles 11b, the insulation between adjacent wirings and the correspondence with each wiring 10a. Both of the electrical continuity between the input wirings 12 are sufficiently secured.

  Further, when the anisotropic conductive adhesive is individually arranged on the driver chip 9 and the flexible wiring board 10, the distance d between the driver chip 9 and the flexible wiring board 10 is set to the arrangement of the anisotropic conductive adhesives. Although it is necessary to make the dimensions to allow for the deviation, in the present invention, since the individual anisotropic conductive adhesives are integrated into one anisotropic conductive adhesive 11, the distance d is equal to the anisotropic conductive adhesive. It is not necessary to consider the misalignment of the adhesive, and it is only necessary to secure dimensions that can absorb the anisotropic conductive adhesive that protrudes during thermocompression bonding without adversely affecting the installation accuracy of each electronic component. . Therefore, the size of the glass substrate 1 of the liquid crystal display element of the present embodiment is such that the distance d between adjacent electronic components, that is, the driver chip 9 and the flexible wiring substrate 10 needs to take into account the displacement of the anisotropic conductive adhesive 11. It will be shortened by the absence of The shortening allowance in the present embodiment is 0.4 mm, and as a result, downsizing of the liquid crystal display element is promoted by 0.4 mm.

  Next, the thermocompression bonding step and the apparatus used therefor in the method for manufacturing the liquid crystal display element of this embodiment will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected about the component same as the said embodiment, and the description is abbreviate | omitted.

  First, the connection area of the driver chip 9 and the flexible wiring board 10 are arranged at predetermined positions on the glass substrate protruding portion 1a where the lead wirings 7 and 8 (see FIG. 2) and their connection terminals in the liquid crystal display element are arranged. An anisotropic conductive adhesive 11 formed in a shape covering the connection region is disposed. Next, the driver chip 9 is placed at a predetermined position on the anisotropic conductive adhesive 11 while being aligned.

Next, the protruding portion 1a of the liquid crystal display element on which the anisotropic conductive adhesive 11 and the driver chip 9 are disposed is placed while being aligned on the cradle 31, as shown in FIG. Here, the support 31 has an area in which the support surface 31 a includes not only the mounting area Ac of the driver chip 9 but also the mounting area Af of the flexible wiring board 10. The cradle 31 is made of aluminum oxide, which is a material having a large thermal conductivity coefficient.

The thermocompression bonding head 32 descends from above the protrusion 1a of the glass substrate 1 supported by the cradle 31. The thermocompression bonding head 32 abuts the front end surface 32a on the upper surface of the driver chip 9, and pressurizes the same while heating it. In this case, the front end surface 32a of the thermocompression bonding head 32 is heated to 210 ° C. and pressurized with a pressure of 600 kgf / Cm ² for 4.5 seconds. As a result, as shown in FIG. 2, the plurality of conductive particles 11b are pressed between the front end surface of the terminal electrode 9a and the corresponding connecting terminal portion surfaces of the lead wires 7 and 8, and are appropriately crushed. This state is maintained by curing the insulating resin substrate 11a made of a thermosetting resin such as an epoxy resin. As a result, the terminal electrodes 9a are securely connected to the connecting terminal portions of the corresponding lead wires 7 and 8 through the conductive particles 11b without short-circuiting each other, and the driver chip 9 is COG at a predetermined position of the protruding portion 1a. It is installed properly by the system.

  Here, the heat conducted from the tip surface 32 a of the thermocompression bonding head 32 to the chip mounting area Ac of the anisotropic conductive adhesive 11 through the driver chip 9 is further conducted to the glass substrate 1. The heat conducted to the glass substrate 1 is further transmitted in the thickness direction and the surface direction. The heat transmitted in the surface direction is transmitted to the arrangement area Af of the flexible wiring substrate of the anisotropic conductive adhesive 11. That is, in the anisotropic conductive adhesive 11 according to the present invention in which the driver chip mounting area Ac and the flexible wiring board placement area Af are integrated, the insulating resin base material 11a in the flexible wiring board mounting area Af is different. In order to receive both the heat transmitted through the isotropic conductive adhesive 11 itself and the heat transmitted through the glass substrate 1, the heat of the driver chip 9 compared to the case where a separate anisotropic conductive adhesive is provided for each conventional area. It is easy to thermoset by heating in the crimping process.

  FIG. 4 shows the change in the thermosetting reaction rate with respect to the distance from the driver chip 9 of the insulating resin base material 11a in the anisotropic conductive adhesive 11, and the solid line shows the case where the cradle 31 of this embodiment is used. The broken line shows the change characteristic when the conventional cradle 33 that supports only the chip mounting area Ac of the anisotropic conductive adhesive 11 is used as shown in FIG.

  As is clear from FIG. 4, in the case of the conventional thermocompression bonding apparatus shown in FIG. 3B, the reaction rate decreases linearly until the distance from the driver chip 9 is about 0.3 mm, but 0.3 mm When it exceeds, the reaction rate becomes substantially constant in the range of about 44 to 50%, and no tendency to decrease is observed.

  On the other hand, in the case of the thermocompression bonding apparatus of the present embodiment using the cradle 31 having the wide support surface 31a, the reaction rate is about 10 to 12% until the distance from the driver chip 9 reaches 0.4 mm. When it falls linearly to a low level and exceeds 0.4 mm, the reaction rate becomes substantially constant in a low range of about 10 to 12%.

This is because, in the case of the thermocompression bonding apparatus of this embodiment according to the present invention, the contact area between the cradle 31 and the glass substrate 1 is wide and the material of the cradle 31 is aluminum oxide having a high thermal conductivity. In the case of the conventional thermocompression bonding apparatus, the contact area between the cradle 33 and the glass substrate 1 is small because the excess heat from the thermocompression bonding head 32 conducted to the heat is efficiently dissipated through the cradle 31. This is because excess heat transmitted to the glass substrate 1 is not efficiently dissipated.

  If the reaction rate of the thermosetting insulating resin substrate 11a is about 10 to 12%, an electronic component can be appropriately thermocompression-mounted in the area. Accordingly, the distance d (see FIG. 2) between the flexible wiring board 10 and the driver chip 9 is set to 0.4 mm or more, and the driver chip 9 is mounted by thermocompression bonding using the thermocompression bonding apparatus of the present invention, so The substrate 10 can be thermocompression-bonded without any trouble.

  The liquid crystal display element on which the COG mounting of the driver chip 9 has been completed is transported to the thermocompression mounting stage of the flexible wiring board 10, and the thermocompression bonding process of substantially the same process as that of the driver chip 9 described above is performed. Is bonded to the corresponding mounting area Af of the anisotropic conductive adhesive 11 by thermocompression bonding. At this time, since the thermosetting reaction rate of the insulating resin base material 11a in the corresponding area Af before mounting the flexible wiring board in the anisotropic conductive adhesive 11 is as low as about 10 to 12% as described above, the flexible wiring board As shown in FIG. 2, 10 is reliably and properly conductively joined without causing a short circuit.

  Thus, according to the thermocompression bonding apparatus of the present invention, even in the case of the conductive installation structure according to the present invention in which the driver chip 9 and the flexible wiring board 10 are conductively installed with one anisotropic conductive adhesive material 11, the driver chip. 9 and the thermocompression bonding process of the flexible wiring board 10 can be carried out in a batch manner in different stages. Therefore, even in a small-scale production environment where line-type continuous production is difficult and limited to off-line (batch-type) production, the driver chip 9 and the flexible wiring board 10 are mounted with a single anisotropic conductive adhesive 11. Thus, it is possible to manufacture a liquid crystal display element to which the conductive installation structure of this embodiment is applied.

The material of the cradle 31 is not limited to aluminum oxide , and may be glass. Since the glass cradle 31 is made of the same material as the glass substrate 1 of the liquid crystal display element to be supported, the thermal expansion coefficient due to heating of the thermocompression bonding head 32 is substantially the same, and distortion due to the difference in thermal expansion coefficient is unlikely to occur. There is an advantage. The brittleness of the glass can be compensated by anodizing the surface.

  As described above, the liquid crystal display element of the present embodiment includes a driver chip 9 for driving liquid crystal and a flexible wiring board 10 for inputting a signal voltage to the liquid crystal display element via a single anisotropic conductive adhesive 11. Since the conductive wiring is installed on the protruding portion 1a of the glass substrate 1 on which the lead wires 7 and 8 of the display element are arranged, the arrangement interval d between the driver chip 9 and the flexible wiring substrate 10 can be shortened to the maximum while leaving a necessary distance. As a result, not only the miniaturization of the liquid crystal display element is promoted, but also the glass substrate combined with the reduction of the material cost and manufacturing man-hour of the anisotropic conductive adhesive by being integrated into one sheet The yield of materials is also improved, contributing to cost reduction of liquid crystal display elements.

  In addition, the thermocompression bonding apparatus of the present embodiment is formed of a material having excellent thermal conductivity, and has both the driver chip mounting area Ac and the flexible wiring board mounting area Af of the single anisotropic conductive adhesive 11. Since the support 31 having a large support area that can be collectively supported is used, not only the driver chip mounting area Ac of the anisotropic conductive adhesive 11 but also the flexible wiring board mounting area Af due to heat when the driver chip 9 is mounted by thermocompression bonding. As a result, it is possible to reliably prevent the occurrence of the problem of starting the curing. As a result, even in the above-described liquid crystal display element of the present embodiment, the thermocompression bonding process of the driver chip 9 and the thermocompression bonding process of the flexible wiring board 10 are performed. It is possible to carry out batch processing at another stage, and it is possible to produce without trouble in a small-scale factory where line-type continuous production is difficult. That.

  In addition, this invention is not limited to said embodiment. For example, the present invention is effectively applied to the case where the number of electronic components that are conductively installed via one anisotropic conductive adhesive is not limited to two, but is three or more.

  In addition, the present invention is not limited to the case where the driver chip of the liquid crystal display element and the flexible wiring board are installed conductively, but the case where the flexible wiring board is of the COF type on which an LSI chip is mounted, or the EL instead of the liquid crystal display element. (Electroluminescence) Needless to say, the present invention can be widely applied to a conductive installation structure of electronic components in electronic devices other than display devices, plasma display panel devices, or display devices.

It is a top view which shows the liquid crystal display module as one Embodiment of this invention. It is typical sectional drawing which cut | disconnects the conduction installation structure of the electronic component in the said liquid crystal display module by the II-II line | wire of FIG. (A) is a side view which shows one Embodiment of the thermocompression bonding apparatus of this invention used for manufacture of the said liquid crystal display module, (b) is a side view which shows the conventional thermocompression bonding apparatus as a comparative example. It is a graph which shows the relationship between the position in an anisotropic conductive adhesive, and a curing reaction rate for each of the present invention and each conventional thermocompression bonding apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Glass substrate 3 Sealing material 4, 5 Electrode 6 Liquid crystal 7, 8 Lead wiring 9 Driver chip 10 Flexible wiring board 11 Anisotropic conductive adhesive 11a Insulating resin base material 11b Conductive particle 12 Input wiring

Claims (6)

An electronic component conduction installation method for installing a first electronic component and a second electronic component in a predetermined installation region on a circuit board on which a wiring pattern is formed via an anisotropic conductive adhesive sheet,
The cradle having a support surface having a larger area than the installation area, so that at least the entire area corresponding to the installation area of the lower surface of the circuit board is in a first state in contact with the support surface. A circuit board is placed, and the one-layer anisotropic conductive adhesive sheet is placed on the installation area on the circuit board, and the first area on the anisotropic conductive adhesive sheet is placed on the first area. A first step of placing the first electronic component;
After the first step , a second step of conducting and installing the first electronic component by pressing the first electronic component toward the circuit board while heating the first electronic component in the first state; ,
After the second step, the second electronic component placed in the second region on the anisotropic conductive adhesive sheet is pressurized toward the circuit board while being heated. A third step of conducting and installing the electronic components;
There is provided a conductive installation method for an electronic component. The circuit board is made of glass,
2. The electronic component conducting installation method according to claim 1, wherein the cradle is made of glass whose support surface is anodized.   In the anisotropic conductive adhesive sheet, the average particle diameter of the conductive particles is ¼ or less of the connection terminal pitch of the smaller one of the first electronic component and the second electronic component. The method for conducting electrical installation of an electronic component according to claim 1, wherein the electronic component is electrically connected. The circuit board is a glass substrate in which lead wirings drawn from electrodes in a liquid crystal display element are arranged in a predetermined pattern,
The first electronic component is a liquid crystal driving LSI chip,
4. The method for electrically installing electronic components according to claim 1, wherein the second electronic component is a flexible wiring board for supplying a signal voltage to the LSI chip.   2. The electronic component conducting installation method according to claim 1, wherein the cradle is formed of aluminum oxide. An LSI chip for driving a liquid crystal and a flexible wiring board for supplying a signal voltage to the LSI chip are installed in a predetermined installation area on the first substrate on which a wiring pattern is formed via an anisotropic conductive adhesive sheet. A method for manufacturing a liquid crystal display element,
A cradle having a support surface having an area larger than that of the installation area is set in a first state in which at least the entire area corresponding to the installation area of the lower surface of the first substrate is in contact with the support surface. The first substrate is placed, and the anisotropic conductive adhesive sheet in the form of a single film is placed on the installation area on the first substrate, and the anisotropic conductive adhesive sheet is placed on the anisotropic conductive adhesive sheet. A first step of placing the LSI chip in a first region;
After the first step , a second step of conductively installing the LSI chip by applying pressure to the first substrate while heating the LSI chip in the first state;
After the second step, the flexible wiring board is pressed by pressing the flexible wiring board placed in the second region on the anisotropic conductive adhesive sheet toward the circuit board while heating. A third step of conducting installation;
A method for producing a liquid crystal display element, comprising:

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