JP2008159849A - Electrode connection structure and electrode connecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode connection structure and an electrode connecting method that suppresses short-circuit defects and secure electric connection reliability against a high voltage and is adaptive to narrower-pitch connection. <P>SOLUTION: The electrode connection structure has: a first circuit forming body having a plurality of first electrodes; a second circuit forming body having a plurality of second electrodes disposed opposite the plurality of first electrodes; insulating adhesive resin disposed in an opposition region of the first and second circuit forming bodies to connect the both to each other; many conductive particles coming into electric contact with tops of the respective second electrodes; and a plurality of particle holding members formed of conductive materials disposed on tops of the respective first electrodes to hold the many conductive particles and electrically connect the many conductive particles directly or indirectly to the respective first electrodes. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrode bonding structure and an electrode bonding method for electrically bonding an electrode of another circuit forming body to an electrode of a circuit forming body through conductive particles.

  Conventionally, as a technique for electrically bonding an electrode of a circuit forming body such as another glass substrate or a flexible substrate or an electronic component to an electrode of a circuit forming body such as a glass substrate or a flexible substrate, about several μm to several tens μm A technique using an insulating adhesive resin in which conductive particles having an average particle size of, for example, an anisotropic conductive sheet are dispersed, is known. This technique arranges an anisotropic conductive sheet between electrodes to be joined, presses the anisotropic conductive sheet with a crimping tool through a circuit forming body, and heats the insulating adhesive. In this technique, a resin is melted and electrical conduction is established between the electrodes via conductive particles.

  This electrode bonding technique using an anisotropic conductive sheet can be applied to various types of electrode bonding, for example, electrode bonding (FOG) between a glass substrate and a flexible substrate, and an electrode between a glass substrate and an IC chip component. Bonding (COG), electrode bonding (COF) between flexible substrate and IC chip component, electrode bonding between printed wiring substrate and IC chip component, electrode bonding between flexible substrate and flexible substrate, electrode between flexible substrate and printed wiring substrate Widely used for bonding, etc.

  In recent years, for example, in flat panel bonding technology represented by electrode bonding between a glass substrate and a flexible substrate, along with ensuring the bonding reliability when a high voltage is applied between the electrodes and increasing the density of electronic devices. Accordingly, there is a demand for further narrowing (miniaturization) between adjacent wiring electrodes. Specifically, the pitch between adjacent wiring electrodes is required to be narrowed from 200 μm to 100 μm, which has been conventionally required, to 100 μm to 50 μm or less. Similarly, in the technology for bonding IC chip components in a face-down manner, such as electrode bonding between a glass substrate and an IC chip component, or electrode bonding between a flexible substrate and an IC chip component, bumps are also developed along with the increase in functionality. There is a demand for further narrowing (miniaturization) between electrodes. Specifically, the pitch between the adjacent wiring electrodes is required to be narrowed from 120 μm to 80 μm, which has been conventionally required, to 80 μm to 40 μm or less.

  When the pitch between adjacent wiring electrodes is reduced to the above level, in the electrode bonding technique using the anisotropic conductive sheet, there is a high possibility of causing problems such as a short circuit failure and a decrease in electrical bonding reliability. Become.

  That is, the short-circuit failure is caused by the fact that the anisotropic conductive sheet 101 is formed so that the glass substrate 104 having the first electrode 104A, for example, faces the first electrode 104A, as shown in FIG. 9A. The anisotropic conductive sheet as shown in FIGS. 9B and 9C by being pressed and heated by the crimping tool 106 in a state of being arranged in the region 100X facing the flexible substrate 105 having the two electrodes 105A. The insulating adhesive resin 102 of 101 melts and flows to the outer region 100Y at the edge of the opposing region 100X, and the conductive particles 103 dispersed in the anisotropic conductive sheet 101 along with this flow become the outer region 100Y. This is caused by agglomeration and aggregation.

  When the pitch between the adjacent wiring electrodes 100P (see FIG. 9C) is reduced (for example, 100 μm to 50 μm or less), the conductive particles 103 that are not involved in electrode bonding can be accumulated in the gap 100S (see FIG. 9C) between the adjacent electrodes. The amount is reduced, and more conductive particles 103 are pushed out to the outer region 100Y and agglomerate in the outer region 100Y, so that a short circuit is likely to occur.

  In addition, when the pitch between the adjacent wiring electrodes 100P is narrowed, the width 100L (see FIG. 9C) of the first and second electrodes 104A and 105A is naturally narrowed, so that it flows along with the flow of the insulating adhesive resin 102. It is difficult to reliably arrange (capture) a large number of conductive particles 103 between the first and second electrodes 104A and 105A. As a result, the number of conductive particles 103 arranged between the electrodes is reduced, so that the electrical connection between the electrodes becomes unstable, and the electrical connection reliability is lowered. In particular, when a high voltage is applied between the electrodes, the deterioration of the bonding reliability becomes remarkable.

  As a technique for preventing the short circuit defect, for example, there is a technique disclosed in Patent Document 1 (Japanese Patent No. 3506424). This is because the conductive particles to which a predetermined adhesive is applied are supplied to the entire surface of the electrode formation surface in a state where a resist film is formed on the electrode formation surface of the circuit formed body other than the electrode, and then the portion other than the electrode In this technique, the conductive particles attached to the electrode are removed to remove the conductive particles. In this case, since the conductive particles are attached to the electrode in advance, even if the insulating adhesive resin placed between other circuit forming bodies is pressed and heated at the time of electrode bonding, the insulating adhesive resin The conductive particles do not flow along with the flow. Therefore, aggregation of conductive particles is suppressed, and short circuit defects are suppressed.

Further, as a technique for ensuring (stabilizing) electrical bonding reliability, for example, there is a technique disclosed in Patent Document 2 (Japanese Patent Laid-Open No. 2006-108523). This is because the anisotropic conductive sheet in which solder particles are dispersed in addition to the conductive particles in the insulating adhesive resin is pressed and heated between the electrodes, and the solder particles are melted to form a gap between the electrodes. It is a technology that ensures bonding reliability by soldering.
Japanese Patent No. 3506424 JP 2006-108523 A

However, in the said patent document 1, in order to remove the electroconductive particle adhering to parts other than an electrode, it is necessary to use etching liquid, such as caustic soda water. Such an etchant is difficult to remove completely, and if electrode bonding is performed in a state in which this etchant remains, there is a problem that bonding reliability is lowered.
In Patent Document 2, for example, in the case of a narrow pitch of L / S = 20 μm / 20 μm (L is the width of the electrode and S is the gap between the adjacent electrodes), a short circuit between the adjacent electrodes is performed. In order to suppress the occurrence of defects, the maximum particle size of the solder particles needs to be less than 20 μm. Since the solder particles of this size have a large specific surface area (surface area per unit volume), the influence when the solder particles are oxidized is large. For this reason, in order to melt the solder particles, it is necessary to use a flux having a considerably strong reducing action. Even if the solder particles can be melted, since the solder particles are dispersed in the insulating adhesive resin, the melted solder particles are caused to flow with the flow of the pressurized and heated insulating adhesive resin. Agglomeration may occur from the viewpoint of surface energy, and this agglomeration may cause a solder bridge and a short circuit. That is, in Patent Document 2, it is difficult to suppress the occurrence of short-circuit defects when the pitch between adjacent wiring electrodes is narrowed.

  Accordingly, an object of the present invention is to solve the above-described problem, and in the electrode bonding in which the electrode of another circuit forming body is electrically bonded to the electrode of the circuit forming body through the conductive particles, a short circuit failure is caused. It is an object of the present invention to provide an electrode bonding structure and an electrode bonding method capable of suppressing the occurrence of occurrence, ensuring electrical bonding reliability at a high voltage, and corresponding to a narrow pitch.

In order to achieve the above object, the present invention is configured as follows.
According to the first aspect of the present invention, a first circuit forming body having a plurality of first electrodes;
A second circuit forming body having a plurality of second electrodes respectively disposed opposite to the plurality of first electrodes;
An insulating adhesive resin that is disposed in an opposing region of the first circuit forming body and the second circuit forming body to join the two;
A number of conductive particles in electrical contact on each of the second electrodes;
Each of the plurality of conductive particles is disposed on each of the first electrodes and holds the plurality of conductive particles, and the plurality of conductive particles are directly or indirectly electrically connected to the first electrodes. A plurality of particle holding members formed of a conductive material;
There is provided an electrode junction structure.

  According to a second aspect of the present invention, there is provided the electrode joint structure according to the first aspect, wherein the particle holding member is made of a solder material.

  According to a third aspect of the present invention, there is provided the electrode joint structure according to the second aspect, wherein the solder material is composed mainly of tin.

  According to the fourth aspect of the present invention, the insulating adhesive resin is a thermosetting resin, and the curing temperature thereof is not higher than the melting temperature of the solder material. Provide a structure.

  According to a fifth aspect of the present invention, the conductive particles include the outermost layer and an inner layer located closer to the center than the outermost layer and having a higher melting temperature than the outermost layer. An electrode junction structure according to any one of the above is provided.

  According to a sixth aspect of the present invention, there is provided the electrode junction structure according to the fifth aspect, wherein the outermost layer is made of gold.

  According to a seventh aspect of the present invention, there is provided the electrode joint structure according to any one of the first to sixth aspects, wherein the conductive particles have a specific gravity greater than that of the particle holding member.

  According to the eighth aspect of the present invention, the average particle diameter of the conductive particles is not less than the average thickness of the particle holding member, and the maximum particle diameter of the conductive particles is between the adjacent second electrodes. The electrode junction structure according to any one of the first to seventh aspects, which is smaller than the gap, is provided.

  According to the ninth aspect of the present invention, the electrode bonding structure according to any one of the first to eighth aspects, further comprising an insulating sealing resin that covers the insulating adhesive resin so as not to be exposed to the outside. Provide the body.

According to the tenth aspect of the present invention, the particle holding member formed of a conductive material is disposed on each of the plurality of first electrodes of the first circuit formation body,
Each of the particle holding members holds the plurality of conductive particles such that the plurality of conductive particles are directly or indirectly electrically connected to the respective first electrodes;
An insulating adhesive resin is disposed in a region facing the second circuit molded body having a plurality of second electrodes formed to face the plurality of first electrodes, respectively.
The insulating adhesive resin is pressurized and heated via the first or second circuit forming body, and the conductive particles electrically connected to the first electrodes and the first electrodes. An electrode joining method is provided in which two electrodes are brought into contact with each other to electrically join each of the first electrodes and each of the second electrodes.

  According to the eleventh aspect of the present invention, the first conductive layer is formed on the first circuit formation body, the second conductive layer is formed on the first conductive layer, and then the first conductive layer is formed. The second conductive layer is patterned together with the layer to form the plurality of first electrodes by the first conductive layer and disposed on each first electrode by the second conductive layer. The electrode joining method according to the tenth aspect, wherein the particle holding member is formed.

According to the twelfth aspect of the present invention, after disposing the particle holding member on each of the first electrodes,
Supplying the plurality of conductive particles on at least each of the particle holding members;
Each of the particle holding members is heated and melted, and part or all of the plurality of conductive particles are electrically joined to the first electrodes by the melted particle holding members. The electrode joining method according to the tenth or eleventh aspect is provided.

According to the thirteenth aspect of the present invention, by supplying the plurality of conductive particles to the formation surface of the plurality of first electrodes of the first circuit forming body, the above-mentioned each particle holding member is provided with the above-mentioned Supply a large number of conductive particles,
After electrically joining a part of the plurality of conductive particles and the respective first electrodes, the electrically conductive particles that are not electrically joined are removed, and then the above-described opposing region is filled with the above-described conductive particles. The electrode bonding method according to the twelfth aspect, in which an insulating adhesive resin is disposed.

According to the fourteenth aspect of the present invention, when supplying the plurality of conductive particles on each of the particle holding members, supplying the plurality of conductive particles in a solvent,
The electrode joining method according to the twelfth or thirteenth aspect, wherein when heating each of the particle holding members, the solvent is evaporated by the heating and dried.

  According to a fifteenth aspect of the present invention, any one of the tenth to fourteenth aspects, wherein the particle holding member formed using a solder material as the conductive material is disposed on each of the first electrodes. The electrode joining method described in 1. is provided.

  According to the sixteenth aspect of the present invention, after the respective first electrodes and the respective second electrodes are electrically joined, the insulating adhesive resin after the pressurization and heating is exposed to the outside. The electrode bonding method according to any one of the tenth to fifteenth aspects is provided, which is covered with an insulating sealing resin so as not to occur.

  According to the electrode bonded structure of the present invention, the conductive particles are directly or indirectly electrically bonded to the respective first electrodes by the particle holding member. Therefore, it is possible to ensure the reliability of electrical connection at a high voltage. In addition, the conductive particles do not aggregate in the outer region of the edge of the opposing region of the first and second circuit forming bodies, and the particle holding member is disposed on the first electrode, so the particle holding members are aggregated together. Therefore, it is possible to suppress the occurrence of a short circuit defect and to cope with a narrow pitch between electrodes (for example, 0.1 mm or less).

  According to the electrode bonding method of the present invention, since the conductive particles are electrically bonded to the first electrodes in advance by the particle holding member, a large number of the conductive particles are placed on the first electrodes. It is possible to ensure electrical connection reliability at a high voltage. In addition, before the insulating adhesive resin flows by pressurization and heating, since the conductive particles are electrically joined to the first electrode by the particle holding member in advance, the insulating adhesive is applied by pressurization and heating. Even if the resin flows, the conductive particles do not aggregate in the outer region of the edge portion of the opposing region of the first and second circuit forming bodies. In addition, since the particle holding member is disposed on the first electrode, the particle holding members do not aggregate. Therefore, it is possible to cope with a narrow pitch between the electrodes (for example, 0.1 mm or less) and to suppress occurrence of a short circuit defect.

Before continuing the description of the present invention, the same parts are denoted by the same reference numerals in the accompanying drawings.
The best mode for carrying out the present invention will be described below with reference to the drawings.

<< First Embodiment >>
The structure of the electrode joint structure according to the first embodiment of the present invention will be described with reference to FIGS. 1A to 1C and FIG. In the first embodiment of the present invention, a description will be given taking as an example a bonding structure of a glass substrate and a flexible substrate, which is a bonding structure of terminal portions of a flat panel. 1A is a plan view schematically showing a configuration of an electrode joint structure according to a first embodiment of the present invention, FIG. 1B is a cross-sectional view taken along line aa in FIG. 1A, and FIG. 1C is FIG. It is bb sectional drawing of. FIG. 2 is a cross-sectional view showing the configuration of the conductive particles.

  The electrode joint structure according to the first embodiment of the present invention is opposed to the flexible substrate 1 as an example of a first circuit formation body having a plurality of first electrodes 1A and the plurality of first electrodes 1A, respectively. Insulating property which is arranged in the opposing region 10X of the glass substrate 2 which is an example of the second circuit formation body having the plurality of second electrodes 2A arranged in a manner and the flexible substrate 1 and the glass substrate 2 and joins them together Adhesive resin 3, a large number of conductive particles 5 in electrical contact with each second electrode 2 </ b> A, and a plurality of conductive particles 5 disposed on each first electrode 1 </ b> A and holding a large number of conductive particles 5. And a solder (material) 4 as an example of a plurality of particle holding members formed of a conductive material that directly or indirectly electrically joins a large number of conductive particles 5 to each first electrode 1A. I have.

The plurality of first electrodes 1A of the flexible substrate 1 are made of, for example, copper electrodes made of copper having a thickness of 10 μm to 50 μm. The gap 1S between the adjacent first electrodes 1A, 1A is configured to be 10 μm to 50 μm, for example.
The plurality of second electrodes 2A of the glass substrate 2 are configured by silver electrodes formed of silver having a thickness of 1 to 10 μm, for example. The silver electrode can be formed by, for example, screen printing or photolithography. The gap between the adjacent second electrodes 2A and 2A is, for example, 10 μm to 50 μm, similarly to the gap 1S between the first electrodes 1A and 1A.

As shown in FIG. 1C, the solder 4 is disposed in close contact with each of the plurality of first electrodes 1A of the flexible substrate 1, that is, disposed so as to seal each of the first electrodes 1A. Of the first electrode 1A. By arranging the solder 4 in this manner, the electrode bonding surface 1a of each first electrode 1A is prevented from being oxidized and hindering conduction.
The solder 4 is composed mainly of tin, and the composition thereof is, for example, Sn, Sn—Cu, Sn—Ag—Cu, Sn—Zn, Sn—Ag—Bi—In, Sn—Ni, Sn— It is made of one selected from Co, Sn—Au, Sn—Bi, and Sn—In.

  Further, the solder 4 is formed in a substantially uniform thickness. If the thickness is too thin, the specific surface area of the solder 4 is increased and the influence of oxidation is increased. If the thickness is too thick, the conductive particles 5 are formed as described later. The average particle diameter of the first electrode must be increased and the bonding stability may be lowered. Therefore, the first particle 1A is formed within a range in which the above problem does not occur according to the width of the first electrode 1A (the horizontal direction in FIG. 1C). ing. For example, the solder 4 is formed with a thickness in the range of 1 μm to 10 μm.

As shown in FIG. 2, the conductive particles 5 are particles in which a metal plate 32, which is an example of an outermost layer, is formed around a spherical core 31, which is an example of an inner layer. The conductive particles 5 react with the component of the metal plating 32 and the component of the solder 4 so as to penetrate the solder 4 around each first electrode 1 </ b> A directly or via the solder 4. It is indirectly electrically connected. The core 31 is made of a conductive material, for example, nickel, copper, gold, silver, aluminum, palladium, resin, or the like. Preferably, the core 31 is made of nickel capable of flowing a high current and a high voltage. The metal plating 32 is formed of a material that can be reacted with tin, which is the main component of the solder 4, and can be joined. Preferably, the metal plating 32 is formed of gold having good bonding properties with tin.
For bonding stability, each material is preferably selected so that the melting temperature of the core 31 is higher than the melting temperature of the metal plating 32 so that the metal plating 32 is melted prior to the core 31.

  The conductive particles 5 are formed so that the average particle diameter is equal to or larger than the average thickness of the solder 4, and the maximum particle diameter is smaller than the gap 1S between adjacent electrodes, preferably from 1/2. It is formed to be smaller. For example, when the thickness of the solder 4 is 5 μm and the gap 1S between adjacent electrodes is 20 μm, the conductive particles 5 have an average particle diameter of 5 μm or more and a maximum particle diameter of less than 10 μm. It is formed as is.

  In addition, when the average particle diameter of the conductive particles 5 is less than the thickness of the solder 4, the conductive particles 5 are completely buried in the solder 4, and the conductive particles 5 contribute to electrode bonding. There is a risk that it will not be possible. Further, when the maximum particle size of the conductive particles 5 is equal to or larger than the gap 1S between the adjacent electrodes, the conductive particles 5 connect the adjacent electrodes to each other, and a short circuit is likely to occur. If the maximum particle diameter of the conductive particles 5 is made smaller than ½ of the gap 1S between the adjacent electrodes, the adjacent first electrodes 1A, 1A are soldered to the surfaces facing each other (the vertical surface in FIG. 1C). It is possible to eliminate contact between the conductive particles 5 soldered by 4 and to further prevent the occurrence of short-circuit defects.

  The insulating adhesive resin 3 is composed of a thermosetting resin, for example, an acrylic resin that cures at a low temperature in a short time when pressed and heated, heat resistance, moisture absorption resistance, adhesiveness, and insulation. It is composed of an epoxy resin that is functionally superior in terms of properties. The insulating adhesive resin 3 is made of a material whose curing temperature is equal to or lower than the melting temperature of the solder 4. The insulating adhesive resin 3 is filled in the facing region 10 </ b> X between the flexible substrate 1 and the glass substrate 2 without a gap, and joins the flexible substrate 1 and the glass substrate 2.

The electrode joint structure according to the first embodiment of the present invention is configured as described above.
According to the electrode joint structure according to the first embodiment of the present invention, since the conductive particles 5 are electrically joined directly or indirectly to the respective first electrodes A by the solder 4, many The conductive particles 5 can be disposed on the first electrode 1A, and electrical bonding reliability at a high voltage can be ensured. Further, in the outer region 10Y adjacent to the outer periphery of the edge of the opposing region 10X on the outside, the conductive particles 5 do not aggregate, and the solder 4 is disposed on the first electrode 1A, so that the solder 4 also aggregates. Therefore, it is possible to suppress the occurrence of short-circuit failure and to cope with a narrow pitch (for example, 0.1 mm or less) between the electrodes.

Moreover, in the electrode junction structure according to the first embodiment of the present invention, the second electrode 2A is formed of silver. Usually, silver has a property (silver erosion) that melts into the solder when it comes into contact with the molten solder. For this reason, in the electrode joint structure in which solder particles are dispersed in an insulating adhesive resin as in Patent Document 2 above, if the electrodes are formed of silver, the electrodes may be dissolved in the solder particles and lost. Can not be formed. On the other hand, according to the electrode joint structure according to the first embodiment of the present invention, the solder 4 is disposed only on the plurality of first electrodes 1A and does not contact the second electrode 2A. Therefore, the second electrode 2A can be formed of silver. Thereby, application to a flat panel etc. is also attained.
In the first embodiment, the second electrode 2A is formed of silver. However, even if the second electrode 2A is formed of a chromium / copper / chromium (Cr / Cu / Cr) thin film or an aluminum (Al) thin film, The present invention can be implemented. Further, in order to suppress the occurrence of migration failure due to voids generated in the insulating adhesive resin, the second electrode 2A is formed by adding palladium (Pd) containing silver (Ag) as a main component. Also, the same effect as described above can be obtained.

  Further, according to the electrode joint structure according to the first embodiment of the present invention, since the curing temperature of the insulating adhesive resin 3 is set to be equal to or lower than the melting temperature of the solder 4, the insulating adhesive resin 3 at the time of electrode joining is obtained. It is possible to prevent the solder 4 from being melted by the pressurization and heating, and to ensure that the solder 4 does not come into contact with the second electrode 2A.

  Next, the electrode joining method according to the first embodiment of the present invention will be described with reference to FIGS. 3A to 3G and FIG. 3A to 3G are cross-sectional views illustrating the procedure of the electrode bonding method according to the first embodiment of the present invention. FIG. 4 is a flowchart of the electrode bonding method according to the first embodiment of the present invention.

First, in step S1, the solder 4 is disposed in close contact with each of the plurality of first electrodes 1A (see FIG. 3A) formed by patterning on the flexible substrate 1 (see FIG. 3B).
Next, in step S2, a solvent 6 such as ethanol mixed with a large number of conductive particles 5 is supplied (for example, applied) onto the solder 4 disposed on each first electrode 1A (see FIG. 3C).

Next, in step S3, each first electrode 1A is heated to melt the solder 4 on each first electrode 1A, and the solder 4 and each metal plating 32 of a large number of conductive particles 5 are bonded. While reacting and electrically joining by soldering, the solvent 6 is evaporated and dried (see FIG. 3D).
At this time, a flux component may be used to melt the solder 4, but it must be cleanable so that there is no residue of the flux component during electrode joining. Other methods for melting the solder 4 include, for example, a method using a reducing atmosphere with hydrogen gas, and a method of locally heating only the first electrode 1A with a soft beam so as not to damage each component. In addition, at this time, when the specific gravity of the conductive particles 5 is larger than the specific gravity of the solder 4, the conductive particles 5 sink into the molten solder 4, and the conductive particles 5 are formed on the first electrode 1A. Is preferable because it can be easily arranged uniformly. For example, when the core 31 of the conductive particles 5 is formed of a material (for example, resin) smaller than the specific gravity of the solder 4, the metal plating 32 is formed of a material (for example, gold) having a larger specific gravity than the solder 4, By increasing the thickness of the metal plating 32, the specific gravity of the conductive particles 5 can be made larger than the specific gravity of the solder 4.

Next, in step S4, the conductive particles 5 that are already electrically bonded to the first electrode 1A by the solder 4 are prevented from moving by the conductive particles 5 that are already electrically bonded to the first electrode 1A. The conductive particles 5 are removed (see FIG. 3E). Through this step, the flexible substrate 1 in which the conductive particles 5 are disposed only on the first electrodes 1A can be obtained.
At this time, the removal of the conductive particles 5 that are not electrically joined can be realized by a simple method such as washing with distilled water.

Next, in step S5, the first electrode 1A of the flexible substrate 1 and the second electrode 2A of the glass substrate 2 are aligned to face each other, and the insulating adhesive resin 3 is disposed in the facing region 10X ( (See FIG. 3F).
At this time, the form of the insulating adhesive resin 3 may be a paste or a sheet (film), but a sheet is preferable because of excellent workability and handleability.
Moreover, it is preferable that the thickness of the insulating adhesive resin 3 is 15 μm to 60 μm. When the thickness of the insulating adhesive resin 3 is less than 15 μm, the electrode bonding strength between the first and second electrodes 1A and 5A is insufficient and is easily peeled off. It becomes difficult to establish conduction between the second electrodes 1A and 2A. Further, the thickness of the insulating adhesive resin 3 is too large to flow from the facing region 10X to the outer region 10Y (see FIG. 1B) when pressed and heated, and adheres to the crimping tool 20 described later. It is preferable that the thickness is appropriately set according to the thickness of the second electrode 2A so that the flexible substrate 1 and the glass substrate 2 do not become insufficient due to being too small. For example, if the thickness of the second electrode 2A is 1 μm to 10 μm, the thickness of the insulating adhesive resin 3 is about 20 μm to 40 μm.
Moreover, the width | variety (in the horizontal direction of FIG. 3F) of the insulating adhesive resin 3 should just be longer than the width | variety by which the flexible substrate 1 and the glass substrate 2 are crimped | bonded.
Further, the insulating adhesive resin 3 may be disposed at a predetermined position when the flexible substrate 1 and the glass substrate 2 are overlaid, and may be attached in advance to the flexible substrate 1 or the glass substrate 2.

  Next, in step S6, the insulating adhesive resin 3 is pressurized and heated by the crimping tool 20 via the flexible substrate 1 (or the glass substrate 2) to be melted, and electrically applied to each first electrode 1A. The conductive particles 5 bonded to the second electrodes 2A and the respective second electrodes 2A are brought into contact with each other, and in this state, the insulating adhesive resin 3 is cured, so that each of the first electrodes 1A and each of the second electrodes 2A is cured. The electrode 2A is electrically joined (see FIG. 3G).

In the electrode joining method according to the first embodiment of the present invention, as shown in FIG. 3G, the crimping tool 20 includes a heater 21 at the lower end and an air cylinder 22 at the upper portion thereof. The motor 23 connected to the motor 22 is configured to be movable up and down by driving. The crimping tool 20 is lowered by driving the motor 23 to bring the pressurizing and heating surface at the lower end thereof into contact with the flexible substrate 1 or the glass substrate 2, and in this contact state, air is supplied to the air cylinder 22 and the air cylinder. As the heater 22 is driven and the heater 8A generates heat, the insulating adhesive resin 3 is pressurized and heated. If the pressure applied by the crimping tool 20 is too weak, the insulating adhesive resin 3 may not flow to the outer region 10Y at the edge of the opposing region 10X, and a portion that is not electrode-bonded may be generated. Since there is a possibility that springback may occur, an appropriate pressure (for example, about 3 MPa) is set.
Further, in the electrode bonding method according to the first embodiment of the present invention, although not shown in the drawing, the electrode bonding is performed by placing the glass substrate 2 on a support stand that is a crimping stage with the glass substrate 2 facing down. To do.

  Through the above steps S1 to S6, the electrode bonding between the flexible substrate 1 and the glass substrate 2 is completed.

  According to the electrode joining method according to the first embodiment of the present invention, since the conductive particles 5 are electrically joined to the respective first electrodes 1A by the solder 4 in advance, a large number of conductive properties are obtained. The particles can be disposed on the first electrode 1A, and electrical connection reliability at a high voltage can be ensured. In addition, before the insulating adhesive resin 3 flows by pressurization and heating, the conductive particles 5 are electrically bonded to the first electrode 1A by the solder 4 in advance, so that the insulating properties can be obtained by pressurization and heating. Even if the adhesive resin 3 flows, the conductive particles 5 do not aggregate in the outer region 10Y at the edge of the facing region 10X. In addition, since the solder 4 is disposed on the first electrode 1A, the solder 4 does not aggregate. Therefore, it is possible to cope with a narrow pitch between the electrodes (for example, 0.1 mm or less) and to suppress occurrence of a short circuit defect. The electrode bonding method according to the first embodiment of the present invention is more useful particularly in a flat panel bonding technique represented by electrode bonding between a glass substrate and a flexible substrate, which requires the above-described effects.

Further, according to the electrode joining method according to the first embodiment of the present invention, when a large number of conductive particles 5 are supplied onto each solder 4, a large number of the conductive particles 5 are supplied in a state of being mixed with a solvent 6. Therefore, handling is easy. On the other hand, for example, when a large number of conductive particles 5 are directly supplied onto the first electrode 1A without being mixed with the solvent 6, the conductive particles 5 have a particle diameter of several μm to several tens μm level. Therefore, there is a possibility that it cannot be placed on the first electrode 1A well, for example, by being scattered in the air by wind.
Moreover, since the solvent 6 can be removed by evaporation and drying using heat when the solder 4 is heated, it is not necessary to perform a special operation to remove the solvent 6.

  In addition, according to the electrode joining method according to the first embodiment of the present invention, the solder 4 is disposed on the first electrode 1A in advance so that the second electrode 2A and the solder 4 do not come into contact with each other. The second electrode 2A can be formed of silver and can be applied to a flat panel or the like.

In addition, this invention is not limited to the said embodiment, It can implement with another various aspect. For example, in the above description, the flexible substrate 1 is given as an example of the first circuit forming body. As the first circuit forming body, in addition to the flexible substrate, a glass epoxy wiring substrate, a polyethylene terephthalate substrate, a polycarbonate substrate, a polyethylene substrate, and the like. Electronic components such as a phthalate substrate, a polyimide substrate, a ceramic substrate, and an IC chip may be used.
In the above description, the glass substrate 2 is given as an example of the second circuit forming body. As the second circuit forming body, in addition to the glass substrate, a flexible substrate, a glass epoxy wiring substrate, a polyethylene terephthalate substrate, A polycarbonate substrate, a polyethylene naphthalate substrate, a polyimide substrate, a ceramic substrate, or the like may be used.
By configuring the first and second circuit formation bodies as described above, a high-quality electrode junction structure can be provided at low cost while maintaining high productivity.
In the above description, the conductive particles 5 have a two-layer configuration of the core 31 and the metal plating 32. However, the present invention is not limited to this, and may have a single-layer configuration or a configuration with more than two layers.
In the above description, the solder 4 is used as an example of the particle holding member. However, the present invention is not limited to this, and for example, a conductive paste in which metal fine particles are mixed can be used.

In the above description, the solder 4 is arranged in close contact with each of the first electrodes 1A. However, the present invention is not limited to this, and the solder 4 is attached to each of the first electrodes 1A as shown in FIG. It may be arranged only on the electrode bonding surface 1a.
Such an arrangement of the solder 4 is, for example, an example in which an electrode film 40 which is an example of a first conductive layer is formed on the flexible substrate 1 (see FIG. 6A), and an example of the second conductive layer is formed on the electrode film 40. After the solder film 41 is formed (see FIG. 6B), the solder film 41 is patterned together with the electrode film 40 (see FIG. 6C). According to such an arrangement method, the manufacturing time can be greatly shortened and the manufacturing can be easily performed as compared with the case where the solder 4 is arranged around each of the first electrodes 1A. Less.
The electrode film 40 is different from the first electrode 1A only in size. Similarly, the solder film 41 is different from the solder 4 only in size.

  A method of supplying the conductive particles 5 to the flexible substrate 1 in which the solder 4 is disposed only on the electrode bonding surface 1a of each first electrode 1A as described above, or the second electrode 2A and the electrode of the glass substrate 2 As shown in FIGS. 6D to 6H, the joining method is the same as steps S2 to S6 described above, and a description thereof will be omitted.

  As described above, by arranging the solder 4 only on the electrode bonding surface 1a of each first electrode 1A, as shown in FIG. 5, on the opposing surfaces of the adjacent first electrodes 1A and 1A. Since the solder 4a does not exist, the conductive particles 5 are not electrically joined between the adjacent first electrodes 1A and 1A. That is, there is no possibility that the conductive particles 5 are aggregated between the adjacent first electrodes 1A and 1A to cause short-circuit failure, and it is possible to cope with further narrow pitch.

  Further, in the above, after supplying a large number of conductive particles 5 onto the solder 4, the first electrodes 1 </ b> A are heated to melt the solder 4, and the molten solder 4 causes a large number of conductive particles 5 and Although each 1st electrode 1A was electrically joined, this invention is not limited to this, Many electroconductive particle 5 is electrically joined with each 1st electrode 1A. In addition, it is only necessary that the solder 4 can hold a large number of conductive particles 5.

<< Second Embodiment >>
The electrode joint structure and the electrode joining method according to the second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a cross-sectional view of an electrode joint structure according to a second embodiment of the present invention. FIG. 8 is a flowchart of the electrode joining method according to the second embodiment of the present invention. The electrode joint structure according to the second embodiment of the present invention is different from the electrode joint structure according to the first embodiment of the present invention in that it further includes an insulating sealing resin 50. The electrode joining method according to the second embodiment of the present invention is further provided with a step S7 of covering with the insulating sealing resin 50 so that the insulating adhesive resin 3 is not exposed to the outside after the step S6. This is different from the electrode bonding method according to the first embodiment of the present invention. Since the other points are the same, redundant description will be omitted, and differences will be mainly described.

As shown in FIG. 7, the insulating sealing resin 50 covers the insulating adhesive resin 3 after pressing and heating located in the outer region 10Y at the edge of the facing region 10X so as not to be exposed to the outside (sealing). To stop). That is, the insulating sealing resin 50 is provided so as to seal the electrode joint portion between the flexible substrate 1 and the glass substrate 2.
By providing the insulating sealing resin 50 in this manner, it is possible to prevent water, corrosive gas, or the like from entering the electrode joint portion between the flexible substrate 1 and the glass substrate 2 from the outside. In addition, since the oxidation of the first and second electrodes 1A and 2A and the conductive particles 5 is prevented and electrical conduction is not hindered, highly reliable bonding quality can be realized. Further, the insulating sealing resin 50 is cured, whereby the electrode joint strength is reinforced and the reliability with respect to the mechanical bending strength and the like is improved.

The insulating sealing resin 50 is preferably composed of a silicone resin, a UV curable resin such as urethane or polybutadiene, and the like. The insulating sealing resin 50 may be cured by heat, may be cured by light, or may be cured by a combination of light and heat.
Moreover, as a material of the insulating sealing resin 50, it is preferable to use a solvent-free resin from the viewpoint of work environment and the problem of redeposition of volatile components.
Further, as the material of the insulating sealing resin 50, it is preferable to use a material having low water permeability and few ionic impurities. Thereby, the ion migration which generate | occur | produces when a voltage is applied in a high-temperature, high-humidity environment can also be prevented.
Further, the material of the insulating sealing resin 50 has a certain degree of flexibility so as to have a reinforcing effect on the bonding strength of the first and second electrodes 1A and 2A and to follow the deformation of the flexible substrate 1. It is preferable that the elastic body has

  The thickness of the insulating sealing resin 50 is preferably set to 0.1 mm to 5.0 mm. When the thickness of the insulating sealing resin 50 is less than 0.1 mm, it is possible to prevent water, corrosive gas, or the like from entering the electrode joint portion between the flexible substrate 1 and the glass substrate 2 from the outside. When it exceeds 5 mm, it takes time for the insulating sealing resin 50 to cure, and the tact time becomes longer.

  Moreover, as a formation method of the insulating sealing resin 50, it is preferable to adopt a method of forming by applying using a dispenser. The coating viscosity in this case is preferably in the range of about 2 mPa · s to 20 Pa · s from the viewpoint of applicability. However, the present invention is not limited to this, and a method of forming by screen printing, inkjet, coater, or the like may be employed according to the viscosity of the insulating sealing resin 50.

  Further, when forming the insulating sealing resin 50, it is preferable to perform UV cleaning in advance in order to improve the adhesion between the flexible substrate 1 and the glass substrate 2 and the insulating sealing resin 50. The electrode bonded structure bonded in this manner can cope with a narrow pitch between electrodes having a pitch of 0.1 mm or less, and is excellent in long-term bonding reliability.

Example 1
Next, Example 1 which is one of the specific examples of the electrode bonding method according to the second embodiment of the present invention will be described with reference to FIGS. 3A to 3G and FIG. 4. First, a specific configuration of each component will be described.

In Example 1, the first circuit formed body is a flexible film in which a plurality of copper electrodes 1A formed of copper having a thickness of 32 μm are arranged on a polyimide film having a thickness of 75 μm with a width of L / S = 50 μm / 50 μm. A substrate 1 is used. Note that L indicates the width of the electrode, and S indicates the width between adjacent electrodes. That is, the pitch between the electrodes having the above configuration is 50 μm + 50 μm = 100 μm = 0.1 mm.
In the first embodiment, the particle holding member is composed of solder 4 mainly composed of tin.
Further, in Example 1, the second circuit formed body has a plurality of silver electrodes 2A formed of silver having a thickness of 3 μm by a screen printing method and baking on a glass having a thickness of 3 mm, L / S = 50 μm / The glass substrate 2 is arranged with a width of 50 μm.
In Example 1, the insulating adhesive resin is formed of a thermosetting epoxy resin sheet 3 that is formed to have a width of 3 mm and a thickness of 35 μm, and uses imitazole as a main curing agent.
Further, in Example 1, the conductive particles are composed of conductive particles 3 that are formed to have a mean particle diameter of about 8 μm by applying nickel plating 31 to a nickel particle 31 with a thickness of 0.05 μm.

In the first embodiment, the insulating sealing resin is composed of the insulating sealing resin 50 made of polybutadiene acrylate which is cured with a cumulative amount of light of 2000 mJ / cm ² with a mercury lamp.
The material of the insulating sealing resin 50 is particularly low in impurity chlorine ion concentration of several ppm, low in water absorption, and excellent in resistance to ion migration that occurs when a voltage is applied in a high temperature and high humidity environment. Whether or not there was a selection criterion.
In addition, in the electrode joint structure that employs an epoxy acrylate resin as the material of the insulating sealing resin 50, since the impurity chlorine ion concentration of the resin is relatively high due to contamination from the raw material, insulation is performed by a THB reliability test. It is confirmed that a defect occurs.

Hereinafter, the electrode joining method of Example 1 will be described.
First, as shown in FIG. 3B, solder 4 is formed with a thickness of 3 μm to 6 μm on the plurality of copper electrodes 1A of the flexible substrate 1 shown in FIG. 3A (step S1 in FIG. 4).
Next, as shown in FIG. 3C, ethanol 6 mixed with a large number of conductive particles 5 is applied onto the solder 4 disposed on each copper electrode 1A (step S2 in FIG. 4).

Next, a hydrogen reducing atmosphere is formed around the flexible substrate 1 with green gas mixed with hydrogen to heat each copper electrode 1A to melt the solder 4 on each copper electrode 1A, as shown in FIG. 3D. As described above, the solder 4 and the gold plating 32 of the conductive particles 5 are reacted and soldered, and the ethanol 6 is evaporated and dried (step S3 in FIG. 4).
At this time, only the nickel particles 31 in contact with the solder 4 are soldered, and the nickel particles 31 and the copper electrode 1A are joined by eutectic bonding of Au (gold) -Sn (tin). An intermetallic compound made of Au (gold) -Ni (nickel) -Sn (tin) is formed at the joint.

Next, the conductive particles 5 that have not been soldered onto the copper electrode 1A are washed with distilled water and removed as shown in FIG. 3E (step S4 in FIG. 4).
Next, after affixing the epoxy resin sheet 3 on the surface of the glass substrate 2 where the silver electrode 2A is formed, the flexible resin substrate 1 is placed so that the epoxy resin sheet 3 is disposed between the flexible substrate 1 and the glass substrate 2. The copper electrode 1A and the silver electrode 2A of the glass substrate 2 are faced and aligned (step S5 in FIG. 4).
At this time, the pressure applied to the epoxy resin sheet 3 was 10 kg / cm 2, and the pressing time was 5 seconds.

Next, as shown in FIG. 3G, the epoxy resin sheet 3 is melted by pressing and heating the flexible substrate 1 with the crimping tool 20 (for example, Bellofram cylinder manufactured by Fujikura Rubber Industry Co., Ltd.). The conductive particles 5 electrically bonded on the electrode 1A and the respective silver electrodes 2A are brought into contact with each other, and the epoxy resin sheet 3 is cured in this state, so that each copper electrode 1A and each silver electrode is cured. 2A is electrically joined (step S6 in FIG. 4).
At this time, the heating time by the crimping tool 20 was 180 ° C., the applied pressure was 3 MPa, and the pressing time was 10 seconds. At this time, in order not to deteriorate the bonding reliability between the nickel particles 31 plated with gold 32 and the solder 4 on the copper electrode 1A, the temperature of the electrode bonding portion is set to Au (gold) -Sn (tin). Care was taken not to heat above the eutectic temperature of.

Next, the epoxy resin sheet 3 after pressing and heating located in the outer region 10Y at the edge of the opposing region 10X is subjected to UV cleaning, and then an insulating sealing resin using a dispenser (for example, manufactured by Musashi Engineering). 50 is applied and covered so as not to be exposed to the outside (step S7 in FIG. 4). At this time, the coating amount of the insulating sealing resin 50 was such that the thickness after photocuring was about 0.5 mm.
In addition, when the thickness of the insulating sealing resin 50 after photocuring is reduced to about several tens of μm, the surface is inhibited from curing, and the surface remains sticky even after UV irradiation. In this state, the THB test was conducted. It has been confirmed that the insulating sealing resin 50 absorbs water and an insulation failure occurs.

Since the electrode bonded structure electrode bonded by the electrode bonding method has a structure in which the conductive particles 5 are pre-soldered to the respective copper electrodes 1A, a large number of conductive particles 5 are arranged on the copper electrode 1A. Electrical connection reliability at high voltage is ensured. Further, in the outer region 10Y at the edge of the facing region 10X, the conductive particles 5 do not aggregate, and since the solder 4 is disposed on the copper electrode 1A, the solder 4 is not aggregated. While being able to suppress, it can respond to the narrow pitch (for example, 0.1 mm or less) between electrodes.
Further, since the solder 4 is disposed only on each copper electrode 1A and does not contact each second electrode 2A, the electrode of the glass substrate 2 can be the silver electrode 2A.
Moreover, since the epoxy resin sheet 3 after pressurization and heating is covered with an insulating sealing resin 50 so as not to be exposed to the outside, water or corrosion is externally applied to the electrode joint portion between the flexible substrate 1 and the glass substrate 2. It is possible to prevent invasion of sex gases and the like. Moreover, since the oxidation of the copper electrode 1A, the silver electrode 2A, and the conductive particles 5 is prevented and the electrical conduction is not hindered, highly reliable bonding quality is realized. Further, the insulating sealing resin 50 is cured, whereby the electrode joint strength is reinforced and the reliability with respect to the mechanical bending strength and the like is improved.

Example 2
Next, Example 2, which is another specific example of the electrode bonding method according to the second embodiment of the present invention, will be described with reference to FIGS. 3A to 3G and FIG. First, a specific configuration of each component will be described.

In Example 2, the first circuit formed body is a flexible film in which a plurality of copper electrodes 1A formed of copper having a thickness of 12 μm are arranged on a polyimide film having a thickness of 50 μm with a width of L / S = 30 μm / 30 μm. A substrate 1 is used. Note that L indicates the width of the electrode, and S indicates the width between adjacent electrodes. That is, the pitch between the electrodes having the above configuration is 30 μm + 30 μm = 60 μm = 0.06 mm.
Moreover, in the present Example 2, the particle holding member is comprised with the solder 4 which has tin as a main component.
Further, in Example 2, the second circuit forming body is a silver nano paste drawn by ink jet on a 75 μm thick PEN (polyethylene naphthalate) film (for example, Neotex (registered trademark) manufactured by Teijin DuPont). A plurality of silver electrodes 2A formed to have a thickness of about 3 μm by firing at 200 ° C. are constituted by a PEN substrate 2 arranged with a width of L / S = 30 μm / 30 μm.
In Example 2, the insulating adhesive resin is composed of a thermosetting insulating resin paste (for example, NCP (non-conductive paste) 3) manufactured by Namics.
Further, in Example 1, the conductive particles are composed of conductive particles 3 that are formed to have an average particle diameter of about 6 μm by applying gold plating 32 having a thickness of 0.5 μm to nickel particles 31.
In the second embodiment, the insulating sealing resin is composed of the insulating sealing resin 50 made of polybutadiene acrylate that is cured with a cumulative amount of light of 2000 mJ / cm ² with a mercury lamp.

Hereinafter, the electrode joining method of Example 2 will be described.
First, as shown in FIG. 3B, the solder 4 is uniformly formed with a thickness of 3 μm on the plurality of copper electrodes 1A of the flexible substrate 1 shown in FIG. 3A (step S1 in FIG. 4).
Next, as shown in FIG. 3C, a water-soluble flux 6 in which a large number of conductive particles 5 are immersed is applied on the solder 4 disposed on each copper electrode 1A (step S2 in FIG. 4).

Next, the solder 4 on each copper electrode 1A is melted by reflow heating, and as shown in FIG. 3D, the solder 4 and the gold plating 32 of the conductive particles 5 are reacted and soldered, and the water-soluble flux 6 is added. Evaporate and dry (step S3 in FIG. 4).
At this time, only the nickel particles 31 in contact with the solder 4 are soldered, and the nickel particles 31 and the copper electrode 1A are joined by eutectic bonding of Au (gold) -Sn (tin). An intermetallic compound made of Au (gold) -Ni (nickel) -Sn (tin) is formed at the joint.

Next, the residue of the water-soluble flux 6 adhering to the flexible substrate 1 and the conductive particles 5 not soldered onto the copper electrode 1A are cleaned using a flux cleaning liquid (for example, Arakawa Chemical Pine Alpha). Each is removed as shown in 3E (step S4 in FIG. 4).
Next, after applying an insulating resin paste 3 by a dispenser so as to seal the silver electrode 2A of the PEN substrate 2, the copper electrode 1A of the flexible substrate 1 and the silver electrode 2A of the PEN substrate 2 are bonded to the insulating resin paste 3. Are positioned so as to face each other (step S5 in FIG. 4).
Next, as shown in FIG. 3G, the insulating resin paste 3 is melted by pressurizing and heating the flexible substrate 1 with a crimping tool 20 (for example, Bellofram cylinder manufactured by Fujikura Rubber Industry Co., Ltd.). The conductive particles 5 electrically bonded on the copper electrode 1A and the respective silver electrodes 2A are brought into contact with each other, and in this state, the insulating resin paste 3 is cured, so that each copper electrode 1A and each of the respective copper electrodes 1A are cured. The silver electrode 2A is electrically joined (step S6 in FIG. 4).
At this time, the heating time by the crimping tool 20 was 180 ° C., the applied pressure was 3 MPa, and the pressing time was 10 seconds. At this time, since the PEN substrate 2 is a weak heat-resistant substrate and has a property of becoming brittle due to crystallization when it is set to a temperature of 200 ° C. or higher, care must be taken that the PEN substrate 2 does not reach a temperature of 200 ° C. or higher. did.

  Next, the epoxy resin sheet 3 after pressing and heating located in the outer region 10Y at the edge of the opposing region 10X is subjected to UV cleaning, and then an insulating sealing resin using a dispenser (for example, manufactured by Musashi Engineering). 50 is applied and covered so as not to be exposed to the outside (step S7 in FIG. 4). At this time, the coating amount of the insulating sealing resin 50 was such that the thickness after photocuring was about 0.5 mm.

Since the electrode bonded structure electrode bonded by the electrode bonding method has a structure in which the conductive particles 5 are pre-soldered to the respective copper electrodes 1A, a large number of conductive particles 5 are arranged on the copper electrode 1A. Electrical connection reliability at high voltage is ensured. Further, in the outer region 10Y at the edge of the facing region 10X, the conductive particles 5 do not aggregate, and since the solder 4 is disposed on the copper electrode 1A, the solder 4 is not aggregated. While being able to suppress, it can respond to the narrow pitch (for example, 0.1 mm or less) between electrodes.
Further, since the solder 4 is disposed only on each copper electrode 1A and does not contact each silver electrode 2A, the electrode of the PEN substrate 2 can be the silver electrode 2A.
Moreover, since the epoxy resin sheet 3 after pressurization and heating is covered and hidden by the insulating sealing resin 50 so as not to be exposed to the outside, water or corrosion is externally applied to the electrode joint portion between the flexible substrate 1 and the PEN substrate 2. It is possible to prevent invasion of sex gases and the like. Moreover, since the oxidation of the copper electrode 1A, the silver electrode 2A, and the conductive particles 5 is prevented and the electrical conduction is not hindered, highly reliable bonding quality is realized. Further, the insulating sealing resin 50 is cured, whereby the electrode joint strength is reinforced and the reliability with respect to the mechanical bending strength and the like is improved.

  In addition, it can be made to show each effect which each embodiment has among each embodiment by combining suitably.

  The electrode bonding method and the electrode bonding structure according to the present invention have the effects of suppressing the occurrence of short-circuit defects, ensuring electrical bonding reliability at high voltages, and being able to cope with narrow pitches. Technology for bonding electrodes of other circuit forming bodies to the electrodes of the forming body using an insulating adhesive resin in which conductive particles are dispersed, particularly flat panel bonding represented by electrode bonding between a glass substrate and a flexible substrate This is useful when the technology requires a narrow pitch between adjacent electrodes.

It is a top view which shows typically the structure of the electrode junction structure concerning 1st Embodiment of this invention. It is aa sectional drawing of FIG. 1A. It is bb sectional drawing of FIG. 1A. It is sectional drawing of electroconductive particle. It is sectional drawing which shows the procedure of the electrode joining method concerning 1st Embodiment of this invention. It is other sectional drawing which shows the procedure of the electrode joining method concerning 1st Embodiment of this invention. It is other sectional drawing which shows the procedure of the electrode joining method concerning 1st Embodiment of this invention. It is other sectional drawing which shows the procedure of the electrode joining method concerning 1st Embodiment of this invention. It is other sectional drawing which shows the procedure of the electrode joining method concerning 1st Embodiment of this invention. It is other sectional drawing which shows the procedure of the electrode joining method concerning 1st Embodiment of this invention. It is other sectional drawing which shows the procedure of the electrode joining method concerning 1st Embodiment of this invention. It is a flowchart of the electrode joining method concerning 1st Embodiment of this invention. It is sectional drawing which shows typically the structure of the electrode junction structure concerning the modification of 1st Embodiment of this invention. It is sectional drawing which shows the procedure of the electrode joining method concerning the modification of 1st Embodiment of this invention. It is other sectional drawing which shows the procedure of the electrode joining method concerning the modification of 1st Embodiment of this invention. It is other sectional drawing which shows the procedure of the electrode joining method concerning the modification of 1st Embodiment of this invention. It is other sectional drawing which shows the procedure of the electrode joining method concerning the modification of 1st Embodiment of this invention. It is other sectional drawing which shows the procedure of the electrode joining method concerning the modification of 1st Embodiment of this invention. It is other sectional drawing which shows the procedure of the electrode joining method concerning the modification of 1st Embodiment of this invention. It is other sectional drawing which shows the procedure of the electrode joining method concerning the modification of 1st Embodiment of this invention. It is other sectional drawing which shows the procedure of the electrode joining method concerning the modification of 1st Embodiment of this invention. It is sectional drawing which shows typically the structure of the electrode junction structure concerning 2nd Embodiment of this invention. It is a flowchart of the electrode joining method concerning 2nd Embodiment of this invention. It is sectional drawing which shows the procedure of the conventional electrode joining method. It is sectional drawing of the conventional electrode junction structure. It is xx sectional drawing of FIG. 9B.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flexible substrate 1A 1st electrode 2 Glass substrate 2A 2nd electrode 3 Insulating adhesive resin 4 Glass substrate 5 Conductive particle 6 Solvent 20 Crimping tool 21 Heating heater 22 Air cylinder 23 Motor 31 Core 32 Metal plating 40 Electrode Film 41 Solder film 50 Insulating sealing resin

Claims (16)

A first circuit forming body having a plurality of first electrodes;
A second circuit forming body having a plurality of second electrodes respectively disposed opposite to the plurality of first electrodes;
An insulating adhesive resin that is disposed in an opposing region of the first circuit forming body and the second circuit forming body to join the two;
A number of conductive particles in electrical contact on each of the second electrodes;
Each of the plurality of conductive particles is disposed on each of the first electrodes and holds the plurality of conductive particles, and the plurality of conductive particles are directly or indirectly electrically connected to the first electrodes. A plurality of particle holding members formed of a conductive material;
An electrode joint structure comprising:   The electrode joint structure according to claim 1, wherein the particle holding member is made of a solder material.   The electrode joint structure according to claim 2, wherein the solder material is composed mainly of tin.   The electrode bonding structure according to claim 2 or 3, wherein the insulating adhesive resin is a thermosetting resin and has a curing temperature equal to or lower than a melting temperature of the solder material.   5. The electrode junction structure according to claim 1, wherein the conductive particles have an outermost layer and an inner layer located closer to the center than the outermost layer and having a higher melting temperature than the outermost layer. body.   The electrode junction structure according to claim 5, wherein the outermost layer is made of gold.   The electrode bonding structure according to claim 1, wherein the conductive particles have a specific gravity greater than that of the particle holding member.   The average particle diameter of the conductive particles is equal to or greater than the average thickness of the particle holding member, and the maximum particle diameter of the conductive particles is smaller than a gap between the adjacent second electrodes. 8. The electrode junction structure according to any one of 7 above.   The electrode bonding structure according to any one of claims 1 to 8, further comprising an insulating sealing resin that covers the insulating adhesive resin so that the insulating adhesive resin is not exposed to the outside. A particle holding member formed of a conductive material is disposed on each of the plurality of first electrodes of the first circuit formation body,
Each of the particle holding members holds the plurality of conductive particles such that the plurality of conductive particles are directly or indirectly electrically connected to the respective first electrodes;
An insulating adhesive resin is disposed in a region facing the second circuit molded body having a plurality of second electrodes formed to face the plurality of first electrodes, respectively.
The insulating adhesive resin is pressurized and heated via the first or second circuit forming body, and the conductive particles electrically connected to the first electrodes and the first electrodes. An electrode joining method in which the two first electrodes are brought into contact with each other to electrically join the first electrodes and the second electrodes.   A first conductive layer is formed on the first circuit formation body, a second conductive layer is formed on the first conductive layer, and then the second conductive layer is patterned together with the first conductive layer. And forming the plurality of first electrodes by the first conductive layer and forming the particle holding member disposed on the first electrodes by the second conductive layer. Item 11. The electrode bonding method according to Item 10. After disposing the particle holding member on each of the first electrodes,
Supplying the plurality of conductive particles on at least each of the particle holding members;
Each of the particle holding members is heated and melted, and part or all of the plurality of conductive particles are electrically joined to the first electrodes by the melted particle holding members. The electrode joining method according to claim 10 or 11. Supplying the plurality of conductive particles on the respective particle holding members by supplying the plurality of conductive particles to the formation surface of the plurality of first electrodes of the first circuit forming body;
After electrically joining a part of the plurality of conductive particles and the respective first electrodes, the electrically conductive particles that are not electrically joined are removed, and then the above-described opposing region is filled with the above-described conductive particles. The electrode bonding method according to claim 12, wherein an insulating adhesive resin is disposed. When supplying the plurality of conductive particles on each of the particle holding members, supplying the plurality of conductive particles mixed with a solvent,
The electrode joining method according to claim 12 or 13, wherein when each of the particle holding members is heated, the solvent is evaporated by the heating and dried.   The electrode joining method according to claim 10, wherein the particle holding member formed using a solder material as the conductive material is disposed on each of the first electrodes.   After electrically connecting the first electrode and the second electrode, the insulating adhesive resin after the pressurization and heating is covered with an insulating sealing resin so as not to be exposed to the outside. The electrode joining method according to claim 10, wherein the electrode joining method is hidden.

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