JP2009010061A - Electrode junction structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode junction structure capable of coping with a smaller pitch between adjacent wiring electrodes by preventing the occurrence of migration. <P>SOLUTION: This electrode bonding structure includes a first circuit forming member having a plurality of first electrodes, a second circuit forming member having a plurality of second electrodes arranged oppositely to the plurality of first electrodes, an insulating adhesive resin arranged in the region between the first circuit forming member and the second circuit forming member via which they are opposed for bonding both of them together, electrically conductive particles dispersed into the insulating adhesive resin for electrically connecting each first electrode and each second electrode opposed thereto together, and an opposite paths forming part which exists in the part of the path located between adjacent second electrodes and having the direction from one second electrode toward the other second electrode along the interface between the second circuit forming member and the insulating adhesive resin and which forms the path having a component in the opposite direction from the other second electrode toward the one second electrode. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrode joint structure in which an electrode of another circuit formation body is electrically joined to an electrode of a circuit formation 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 a flexible substrate and an IC chip component, electrode bonding between a printed wiring substrate and an IC chip component, electrode bonding between a flexible substrate and a flexible substrate, and between a flexible substrate and a printed wiring substrate Widely used for electrode bonding.

  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. For example, when the interval between adjacent wiring electrodes becomes narrow, the electric field strength (= voltage / wiring interval) generated between adjacent wiring electrodes increases, and ion migration is likely to occur due to a potential difference between the electrodes.

  Here, the ion migration means that when a metal such as copper (Cu) or silver (Ag) is used as a wiring electrode material, the metal ions in each electrode are insulatively bonded to the substrate between adjacent wiring electrodes. This is a phenomenon in which the adjacent wiring electrodes are short-circuited by the metal that has moved along the interface with the agent resin and moved toward each other electrode and deposited. In particular, silver (Ag) is known as a material that easily causes ion migration among metals.

  On the other hand, an epoxy resin, which is a thermosetting resin that is generally used as an insulating resin of an anisotropic conductive sheet, is a member that cannot prevent impurity ions such as chlorine from being mixed due to its manufacturing method. This impurity ion becomes a factor that accelerates ion migration when the resin absorbs moisture. For this reason, in electrode joining technology using an anisotropic conductive sheet (especially when silver (Ag) is used as the material of the wiring electrode), in order to cope with a narrow pitch between adjacent wiring electrodes, ion migration is generated. Suppressing and ensuring insulation between adjacent wiring electrodes is an important issue.

  As a technique for suppressing ion migration, for example, there is a technique disclosed in Patent Document 1 (Japanese Patent No. 2964730). This is a technique for forming an insulating layer barrier by screen printing between adjacent wiring electrodes. This insulating layer barrier is formed below the total height (thickness) of the electrodes facing each other. Thereby, since the thermosetting binder which comprises an anisotropic conductive sheet can fully be filled so that adjacent wiring electrodes may be connected, connection reliability can be ensured. Furthermore, since the insulating barrier disposed between adjacent wiring electrodes serves as a barrier for ion migration, the occurrence of short-circuit defects can be suppressed.

As another technique for forming an ion migration barrier between adjacent wiring electrodes, for example, there is a technique disclosed in Patent Document 2 (Japanese Patent Laid-Open No. 2000-183470). This is because, between adjacent wiring electrodes, a barrier paste is formed by screen-printing a paste made of a mixture of powdered inorganic ion exchanger made of hydrous antimony and hydrous bismuth hydrous and liquid epoxy resin, and curing it. Is a technology to form
Japanese Patent No. 2964730 JP 2000-183470 A

  However, in Patent Document 1, when the pitch between adjacent wiring electrodes is narrowed, ion migration cannot be suppressed, and a short circuit may occur. That is, when the pitch between adjacent wiring electrodes is narrowed and the electric field strength is increased, the movement of metal ions in each electrode becomes active due to the electric field. This increases the number of metal ions that move to the electrodes beyond the insulating barrier, resulting in a short circuit failure. In addition, metal ions move along the interface between the insulating barrier and the substrate, which may cause a short circuit failure. Therefore, in Patent Document 1, it is difficult to cope with a narrow pitch between adjacent wiring electrodes.

  Moreover, in the said patent document 2, the barrier of ion migration is comprised with the ion exchanger. However, since the effect of the ion exchanger is limited, it is difficult to suppress ion migration every time it is used. In addition, metal ions may move along the interface between the barrier and the substrate, and a short circuit failure may occur. Therefore, according to Patent Document 2 described above, it is difficult to cope with a narrow pitch between adjacent wiring electrodes.

  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, An object of the present invention is to provide an electrode joint structure that can prevent generation and cope with a narrow pitch between adjacent wiring electrodes.

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 and bonds the two;
Located between the second electrodes adjacent to each other, at the interface between the second circuit forming body and the insulating adhesive resin, along the interface from one second electrode to the other second electrode A reverse path forming unit that forms a path having a component in a reverse direction from the other second electrode toward the one second electrode in a part of the path;
An electrode joint structure is provided.

  According to a second aspect of the present invention, there is provided the electrode junction structure according to the first aspect, wherein the reverse path forming unit forms two paths having the components in the reverse direction.

  According to a third aspect of the present invention, there is provided the electrode junction structure according to the first aspect, wherein the reverse path forming portion is constituted by a protrusion formed on the second circuit forming body. .

  According to a fourth aspect of the present invention, there is provided the electrode joint structure according to the third aspect, wherein the protrusion extends in parallel with the second electrode.

  According to a fifth aspect of the present invention, in the electrode junction structure according to the fifth aspect, the protrusion portion forms a path having the component in the reverse direction by a surface located on the one second electrode side. I will provide a.

  According to a sixth aspect of the present invention, there is provided the electrode joint structure according to the third aspect, wherein the protrusion has a tapered cross-sectional shape that widens toward the first circuit forming body.

According to a seventh aspect of the present invention, the protrusion includes a first protrusion forming part formed on the second circuit forming body and a second protrusion formed on the first protrusion forming member. A projection forming portion,
A surface of the second protrusion forming portion adjacent to the first protrusion forming portion is larger than a surface of the first protrusion forming portion adjacent to the second protrusion forming portion; An electrode junction structure according to an aspect is provided.

  According to an eighth aspect of the present invention, in the electrode joining according to the third aspect, the height of the protrusion is lower than the total height of the height of the first electrode and the height of the second electrode. Provide a structure.

  According to a ninth aspect of the present invention, there is provided the electrode joint structure according to the third aspect, wherein the protrusion is made of the same material as the second circuit forming body.

  According to a tenth aspect of the present invention, there is provided the electrode joint structure according to the third aspect, wherein the protrusion is made of a material that can be covalently bonded to the second circuit forming body.

  According to an eleventh aspect of the present invention, there is provided the electrode joint structure according to the third aspect, wherein the protrusion is made of an inorganic / organic composite material.

According to the twelfth aspect of the present invention, the second circuit forming body is composed of a first material mainly composed of glass,
The protruding portion provides the electrode junction structure according to the third aspect, which is made of a second material containing glass as a main component and having a melting point lower than that of the first material.

  According to a thirteenth aspect of the present invention, the protrusion includes the electrode bonding structure according to the third aspect, containing a photosensitive resin.

  According to a fourteenth aspect of the present invention, there is provided the electrode junction structure according to the first aspect, wherein the reverse path forming portion is constituted by a recess formed in the second circuit forming body.

  According to a fifteenth aspect of the present invention, there is provided the electrode joint structure according to the fourteenth aspect, wherein the recess extends in parallel with the second electrode.

  According to a sixteenth aspect of the present invention, in the electrode junction structure according to the fifteenth aspect, the recess forms a path having the component in the reverse direction by a surface located on the one second electrode side. provide.

  According to a seventeenth aspect of the present invention, there is provided the electrode junction structure according to the fourteenth aspect, wherein the concave portion has a tapered cross-sectional shape that widens in a direction away from the first circuit forming body.

  According to an eighteenth aspect of the present invention, there is provided the electrode junction structure according to any one of the first to seventeenth aspects, wherein each of the second electrodes is formed of silver.

  According to a nineteenth aspect of the present invention, there is provided the electrode joint structure according to any one of the first to eighteenth aspects, wherein the insulating adhesive resin is a thermosetting resin.

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

  According to the electrode junction structure of the present invention, the reverse path forming portion is provided between the second electrodes adjacent to each other. By this reverse path forming portion, the moving direction of the metal ions from one second electrode toward the other second electrode is changed to a direction having a component opposite to the direction toward the other second electrode. Can do. That is, the metal ions in one second electrode cannot reach the other second electrode. Therefore, the occurrence of migration can be prevented, and a narrow pitch (for example, 0.1 mm or less) between adjacent wiring electrodes can be dealt with.

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 >>
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. FIG. 1A is a plan view schematically showing the configuration of the electrode junction structure according to the first embodiment of the present invention, and FIG. 1B is a cross-sectional view along the line aa in FIG. 1A. 1C is a cross-sectional view taken along line bb of FIG. 1A, and FIG. 1D is a partially enlarged cross-sectional view of FIG. 1C. FIG. 2 is a cross-sectional view showing a specific 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 An adhesive resin 3 and an insulating barrier 4 which is an example of a protrusion formed on the glass substrate 2 and between the electrodes 2A and 2A adjacent to each other are provided.

  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 glass substrate 2 is comprised by the material (1st material) which has glass as a main component. 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.

  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 configured to protrude into the outer region 10Y at the edge of the facing region 10X so that the facing region 10X between the flexible substrate 1 and the glass substrate 2 is filled without a gap (FIG. 1B). reference). Thereby, the insulating adhesive resin 3 firmly bonds the flexible substrate 1 and the glass substrate 2.

  Conductive particles 5 are dispersed in the insulating adhesive resin 3. The average particle diameter of the conductive particles 5 is set to about several μm (for example, 5 μm). A part of the conductive particles 5 in the insulating adhesive resin 3 is located between the first electrode 1A and the second electrode 2A and electrically connects them. For example, as shown in FIG. 2, the conductive particles 5 are particles in which a metal plating 5b is formed around a spherical core 5a. The core 5a is made of a conductive material, for example, nickel, copper, gold, silver, aluminum, palladium, resin, or the like. Preferably, the core 5a is formed of nickel capable of flowing a high current and a high voltage. The metal plating 5b is formed of gold having good bondability with tin and excellent stability.

  The insulating barrier 4 extends in a strip shape in parallel between the second electrodes 2A and 2A adjacent to each other. As shown in FIG. 1C, the insulating barrier 4 is formed to have a tapered (for example, trapezoidal) cross-sectional shape extending from the glass substrate 2 toward the flexible substrate 1. In other words, the insulating barrier 4 is formed such that an angle θ1 formed by the tapered portion and the surface of the glass substrate 2 is smaller than 90 degrees. Such a shape can be formed by performing exposure and etching, for example. More specifically, the insulating barrier 4 can be formed in the shape described above by controlling the etching process time and actively utilizing the over-edge state. Note that when the insulating barrier 4 is formed by exposure and etching, a photosensitive resin is used as the binder of the insulating barrier 4.

  As shown in FIG. 1D, the insulating barrier 4 is formed in the above-described shape, and the second electrode 2A and the second electrode 2A adjacent to each other are directed from the second electrode 2A to the other second electrode 2A. Forming a path 110 having a component (vector) 111 in the reverse direction (−X direction) from the other second electrode 2A toward the second electrode 2A in a part of the path 100 in the X direction along the interface. it can. Thereby, when the metal ion in one 2nd electrode 2A moves toward the other 2nd electrode 2A, it is an insulation barrier in the direction (-X direction) which returns to the 1st 2nd electrode 2A side. 4 is reflected. That is, the moving direction of the metal ions in one second electrode 2A is changed to a direction having a component 111 in the opposite direction (−X direction) to the direction (X direction) toward the other second electrode 2A. . Accordingly, the metal ions in one second electrode 2A cannot go to the other second electrode 2A across the insulating barrier 4, and thus migration is prevented.

  Here, there are two paths 110 having the component 111 in the opposite direction, that is, a surface located on one second electrode 2A side of the insulating barrier 4 and a surface located on the other second electrode 2A side. Is formed. This reliably prevents the metal ions in one second electrode 2A from going over the insulating barrier 4 toward the other second electrode 2A.

  The insulating barrier 4 is made of the same material as the glass substrate 2. Here, the “homogeneous material” means that the insulating barrier 4 is made of the glass substrate 2 so that the metal ions contained in the second electrode 2A can be prevented from moving on the interface between the glass substrate 2 and the insulating barrier 4. Means a material that can be integrally bonded (for example, covalently bonded). For example, as the material of the insulating barrier 4, a material containing an inorganic component can be used. As the material of the insulating barrier 4, a material mainly composed of glass (for example, a metal oxide glass such as lead borosilicate glass) can be used in accordance with the material of the glass substrate 2. Furthermore, as the material of the insulating barrier 4, an inorganic / organic composite material (inorganic / organic hybrid material) can be used. In general, it is known that an inorganic material and an inorganic material, an organic material and an organic material have good bonding properties, and an inorganic material and an organic material have poor bonding properties. For this reason, the bonding property between the insulating barrier 4 and the glass substrate 2 made of an inorganic material and the insulating adhesive resin 3 made of an organic material by making the material of the insulating barrier 4 an inorganic / organic composite material. Can be improved.

  The material of the insulating barrier 4 is a material having a lower melting point than the material of the glass substrate 2 (for example, low-melting glass: second glass) so that the glass substrate 2 does not melt when the insulating barrier 4 is formed on the glass substrate 2. It is preferable that the material.

  Further, the height of the insulating barrier 4 is set lower than the total height of the height (thickness) of the first electrode 1A and the height (thickness) of the second electrode 2A. Thus, the insulating adhesive resin 3 is prevented from being filled between the first electrodes 1A and 1A adjacent to each other, and the bonding reliability between the flexible substrate 1 and the glass substrate 2 by the resin insulating adhesive resin 3 is improved. Secured.

  Next, a method for manufacturing the electrode joint structure according to the first embodiment of the present invention will be described with reference to FIGS. 1C, 3 </ b> A to 3 </ b> F, and FIG. 4. 3A to 3F are cross-sectional views illustrating a method for manufacturing the electrode joint structure according to the first embodiment of the present invention. FIG. 4 is a flowchart showing the method for manufacturing the electrode joint structure according to the first embodiment of the present invention.

In addition, in the manufacturing method of the electrode junction structure concerning 1st Embodiment of this invention, the crimping | compression-bonding tool 20 shown to FIG. 3F is used. The crimping tool 20 is provided with a heater 21 at the lower end and an air cylinder 22 at the top, and is configured to move up and down when a motor 23 connected to the air cylinder 22 is driven.
Moreover, in the manufacturing method of the electrode junction structure concerning 1st Embodiment of this invention, although not shown in figure, it mounts on the support stand which is a crimping | compression-bonding stage in the state which faced the glass substrate 2, and electrode joining was carried out. Shall be done.

First, in step S1, a plurality of second electrodes 2A are formed on the glass substrate 2 as shown in FIG. 3A.
In step S2, as shown in FIG. 3B, an insulating barrier material layer 4A is formed on the glass substrate 2 so as to cover each second electrode 2A.
In step S3, as shown in FIG. 3C, the insulating barrier material layer 4A is exposed and etched to form the insulating barrier 4. At this time, the insulating barrier 4 contains a photosensitive resin.
In step S4, as shown in FIG. 3D, the insulating adhesive resin 3 in which the conductive particles 5 are dispersed is disposed on the insulating partition 4.
In step S5, as shown in FIG. 3E, the flexible substrate 1 is placed on the insulating adhesive resin 3, and each first electrode 1A is opposed to each second electrode 2A via the insulating adhesive resin 3. Align and arrange so that.

In step S6, the insulating adhesive resin 3 is pressurized and heated through the flexible substrate 1 by the crimping tool 20 shown in FIG. 3F to melt the insulating adhesive resin 3.
More specifically, the crimping tool 20 is lowered by driving the motor 23, and the pressure heating surface of the heater 21 is brought into contact with the flexible substrate 1. In this contact state, the motor 23 is further driven to lower the crimping tool 20, and the heater 21 is heated. Thereby, the insulating adhesive resin 3 is pressurized and heated through the flexible substrate 1 to melt the insulating adhesive resin 3.

By the step S6, the conductive particles 5 are disposed between the first electrode 1A and the second electrode 2A, and the first electrode 1A and the second electrode 2A are electrically connected via the conductive particles 5. Connected to.
By performing the above steps S1 to S6, the electrode bonded structure according to the first embodiment of the present invention shown in FIG. 1C can be manufactured.

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 the joining reliability may not be ensured. Therefore, the pressure is set to an appropriate pressure (for example, about 3 MPa).
In the above, pressurization and heating of the insulating adhesive resin 3 are performed by bringing the crimping tool 20 into contact with the flexible substrate 1, but may be performed by bringing the crimping tool 20 into contact with the glass substrate 2. .

  As described above, according to the electrode bonded structure according to the first embodiment of the present invention, the insulating barrier 4 made of the same material as the glass substrate 2 is provided between the second electrodes 2A and 2A adjacent to each other. . As a result, it is possible to prevent the metal ions in one second electrode 2A from moving to the other second electrode 2A at the interface between the glass substrate 2 and the insulating barrier 4, so that the occurrence of migration can be prevented. Can be suppressed. In addition, since the occurrence of migration can be suppressed, the pitch between adjacent wiring electrodes (here, the first electrodes 1A and 1A adjacent to each other or the second electrodes 2A and 2A) is reduced (for example, 0.1 mm or less). ).

  Moreover, according to the electrode bonding structure according to the first embodiment of the present invention, the insulating barrier 4 is formed so as to have a tapered cross-sectional shape that widens from the glass substrate 2 toward the flexible substrate 1. As a result, the movement direction of the metal ions in one second electrode 2A is changed to a direction having a component 111 in the direction opposite to the direction toward the other second electrode 2A (X direction) (−X direction). Therefore, the occurrence of migration can be prevented. Moreover, since the occurrence of migration can be prevented, it is possible to cope with a narrow pitch between adjacent wiring electrodes.

  Moreover, according to the electrode junction structure according to the first embodiment of the present invention, since the insulating barrier 4 is provided between the electrodes adjacent to each other, aggregation of the conductive particles 5 between the electrodes can be suppressed, A large number of conductive particles 5 can be arranged between the first electrode 1A and the second electrode 2A to ensure electrical conduction. On the other hand, when the insulating barrier 4 is not provided, in the manufacturing process in which the insulating adhesive resin 3 is heated and pressurized, a large number of conductive particles 5 flow between adjacent electrodes. For this reason, there exists a possibility that the electroconductive particle 5 may aggregate between the said electrodes and a short circuit defect may generate | occur | produce. Further, the conductive particles 5 cannot be arranged (captured) between the first electrode 1A and the second electrode 2A, and there is a possibility that electrical conduction cannot be ensured.

  The electrode bonding structure bonding technique according to the first embodiment of the present invention is a flat panel bonding technique represented by electrode bonding between a glass substrate and a flexible substrate, particularly where a narrow pitch between adjacent wiring electrodes is required. Is more effective. In particular, there is a great effect when the electrode is made of silver.

<< Second Embodiment >>
An electrode joint structure according to a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view showing the configuration of the electrode joint structure 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 of the first embodiment in that an insulating barrier 41 which is an example of a protrusion is provided instead of the insulating barrier 4. Since it is the same about other points, the overlapping description is omitted, and the differences will be mainly described below.

  In FIG. 5, the insulating barrier 41 includes a first barrier 42 that is an example of a first protrusion forming portion formed on the glass substrate 2, and a second protrusion forming portion formed on the first barrier 42. And a second barrier 43, which is an example. Each of the first barrier 42 and the second barrier 43 extends in a strip shape in parallel between the adjacent second electrodes 2A and 2A, and has a rectangular cross-sectional shape as shown in FIG. . The first barrier 42 and the second barrier 43 are each made of the same material as the glass substrate 2, for example, low melting point glass. The second barrier 43 is made of a material having a melting point higher than that of the first barrier 42. The surface (contact surface) of the second barrier 43 adjacent to the first barrier 42 is formed to be larger than the surface of the first barrier 42 adjacent to the second barrier 43. Thereby, the surface 42a where the second barrier 43 and the glass substrate 2 face each other without the first barrier 43 interposed therebetween is formed.

  In the second embodiment of the present invention, the opposing surface 42a causes a part of the path along the interface from the one second electrode 2A to the other second electrode 2A, and from the other second electrode 2A. A path having a component in the opposite direction toward the second electrode 2A is formed. As a result, the metal ions in one second electrode 2A cannot go to the other second electrode 2A beyond the insulating barrier 41, and thus migration is prevented.

  Next, a method for manufacturing an electrode joint structure according to a second embodiment of the present invention will be described with reference to FIGS. 6A to 6B. 6A to 6F are cross-sectional views showing a method for manufacturing an electrode joint structure according to a second embodiment of the present invention, and FIG. 7 is a flowchart thereof.

First, in step S21, a plurality of second electrodes 2A are formed on the glass substrate 2 as shown in FIG. 6A.
In step S22, as shown in FIG. 6B, a first barrier 42 is formed by screen printing or the like on the glass substrate 2 and between the second electrodes 2A and 2A adjacent to each other. At this time, the state of the first barrier 42 is assumed to be in a paste state. At this time, the width of the first barrier 42 is, for example, 25 μm, and the thickness thereof is, for example, about 5 μm.

In step S <b> 23, as shown in FIG. 6C, a rod-shaped second barrier 43 having a rectangular cross section is positioned and arranged on the first barrier 42. At this time, the width of the second barrier 43 is, for example, 30 μm so as to be larger than the width of the first barrier 42, and the thickness thereof is, for example, 10 μm.
In step S24, the entire first barrier 42 is heated to the melting point or higher and then cured. Thereby, the glass substrate, the first barrier 42, and the second barrier 43 are integrated so that the metal ions in the second electrode 2A cannot move through the inside.
In step S <b> 25, as shown in FIG. 6D, the insulating adhesive resin 3 in which the conductive particles 5 are dispersed is disposed on the second partition wall 43.
In step S26, as shown in FIG. 6E, the flexible substrate 1 is placed on the insulating adhesive resin 3, and each first electrode 1A is opposed to each second electrode 2A via the insulating adhesive resin 3. Align and arrange so that.

In step S27, the insulating adhesive resin 3 is pressurized and heated through the flexible substrate 1 by the crimping tool 20 shown in FIG. 6F to melt the insulating adhesive resin 3. As a result, the conductive particles 5 are arranged between the first electrode 1A and the second electrode 2A, and the first electrode 1A and the second electrode 2A are electrically connected via the conductive particles 5. Is done.
By performing the above steps S21 to S27, the electrode joint structure according to the second embodiment of the present invention shown in FIG. 5 can be manufactured.

  According to the electrode junction structure according to the second embodiment of the present invention, the surface of the second barrier 43 adjacent to the first barrier 42 is adjacent to the second barrier 43 of the first barrier 42. By forming it larger than the side surface, the second electrode 2A from the second electrode 2A to the second electrode 2A is formed in a part of the path along the interface from the second electrode 2A to the second electrode 2A. Forming a path having a component in the opposite direction toward. Thereby, generation | occurrence | production of migration can be prevented and it can respond to narrow pitch (for example, 0.1 mm or less) between adjacent wiring electrodes.

Moreover, according to the electrode junction structure according to the second embodiment of the present invention, the insulating barrier 41 is constituted by two members, the first barrier 42 and the second barrier 43. Thus, even if the insulating barrier 41 does not have a tapered cross-sectional shape (see FIG. 1C), the first barrier 42 and the second barrier 43 having a rectangular cross-sectional shape have the above-described components in the reverse direction. A path can be formed.
In the above description, the insulating barrier 41 is composed of two members, but it may be composed of more members.

<< Third Embodiment >>
The electrode junction structure according to the third embodiment of the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional view showing the configuration of the electrode joint structure according to the third embodiment of the present invention. The electrode bonding structure according to the third embodiment of the present invention is different from the electrode bonding structure of the first embodiment in that a concave portion 2B is provided in the glass substrate 2 instead of the insulating barrier 4. Since it is the same about other points, the overlapping description is omitted, and the differences will be mainly described below.

  In FIG. 8, the glass substrate 2 has a recess 2B formed between the second electrodes 2A and 2A adjacent to each other. The recess 2B has a tapered (for example, trapezoidal) cross-sectional shape that widens in a direction away from the flexible substrate 1. In other words, the recess 2B is formed such that an angle θ2 formed by the tapered portion and the surface of the glass substrate 2 is smaller than 90 degrees. This shape can be realized by using, for example, a sandblast method.

  In the third embodiment of the present invention, the tapered portion of the recess 2B causes the other second electrode to be part of the path along the interface from the second electrode 2A to the second electrode 2A. A path having a component in the opposite direction from the electrode 2A toward the second electrode 2A is formed. Thereby, since the metal ion in one 2nd electrode 2A cannot go to the other 2nd electrode 2A across the insulation barrier 4, generation | occurrence | production of migration is prevented. Moreover, since the occurrence of migration can be prevented, it is possible to cope with a narrow pitch (for example, 0.1 mm or less) between adjacent wiring electrodes.

<< 4th Embodiment >>
The electrode junction structure according to the fourth embodiment of the present invention will be described with reference to FIG. FIG. 9: is sectional drawing which shows the structure of the electrode junction structure concerning 4th Embodiment of this invention. The electrode joint structure according to the fifth embodiment of the present invention is further different from the electrode joint structure of the first embodiment of the present invention in that an insulating sealing resin 50 is provided. Since it is the same about other points, the overlapping description is omitted, and the differences will be mainly described below.

In FIG. 9, the insulating sealing resin 50 covers (seals) the insulating adhesive resin 3 after pressing and heating located in the outer region 10Y at the edge of the opposing region 10X so as not to be exposed to the outside. It is provided as follows. 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 thus bonded to the electrode 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.

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 taken 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, polyethylene terephthalate (PET) is used. ) A substrate, a polycarbonate substrate, a polyethylene naphthalate (PEN) substrate, a polyimide substrate, a ceramic substrate, or the like may be used. In this case, the insulating barrier 4 may be made of a material having the same quality as those materials in accordance with the material of those substrates. For example, when an organic substrate such as a PEN substrate or a PET substrate is adopted as the second circuit formation body, the insulating barrier 4 may be made of, for example, an organic resin or an inorganic / organic composite material. 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 electrode bonding is performed using the insulating adhesive resin 3 (so-called ACF) in which the conductive particles 5 are dispersed, but the present invention is not limited to this. For example, electrode bonding may be performed using NCF (non-conductive film), NCP (non-conductive paste), or the like as the insulating adhesive resin 3. In this case, for example, a metal bump is formed on the first electrode 1A in advance, and the metal bump is bonded to the second electrode 2A through the NCF or NCP (so-called NSD method). Also good. Further, for example, by forming a bump with a conductive paste on the first electrode 1A in advance and connecting the bump to the second electrode 2A through NCF or NCP (so-called SBB method), the electrode You may join.
In the above description, the insulating barrier 4 is provided between the second electrodes 2A and 2A adjacent to each other. However, the insulating barrier 4 may be provided, for example, as shown in FIG. That is, the insulating barrier 4 may be configured to be in direct contact with the second electrodes 2A and 2A. Further, the width of the insulating barrier 4 may be longer than the width between the first electrodes 1A and 1A adjacent to each other. In this case, the height of the insulating barrier 4 is set to be at least higher than the height of the first electrode 1A and lower than the total height of the height of the first electrode 1A and the particle diameter of the conductive particles 5.

  1C shows that the insulating barrier 4 is a trapezoidal protrusion, and FIG. 8 shows that the recess 2B is a trapezoidal recess, the present invention is not limited to this. For example, the shape shown in FIG. 11A or FIG. 11B may be used. At the interface between the insulating barrier 4 or the recess 2B and the insulating adhesive resin 3, the other second electrode is formed in a part of the path along the interface from the one second electrode 2A to the other second electrode 2A. The path | route which has a component of the reverse direction which goes to 2 A of one 2nd electrodes from 2A should just be formed. Here, the configuration for forming such a path is referred to as a “reverse path forming unit”. The insulating barrier 4 and the recess 2B are examples of reverse path forming portions, respectively.

In the above description, the insulating barrier 4 is formed in a strip shape in parallel with the second electrodes 2A and 2A adjacent to each other as shown in FIG. 1, but the present invention is not limited to this. For example, the insulating barrier 4 may be divided into a large number. Further, the insulating barrier 4 may be partially disposed in a portion where migration may occur.
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.

  It is to be noted that, by appropriately combining arbitrary embodiments of the various embodiments described above, the effects possessed by them can be produced.

"Example"
Next, an example which is one of the specific examples of the method for manufacturing the electrode joint structure according to the fourth embodiment of the present invention will be described with reference to FIGS. 1C, 3A to 3F, and FIG. First, a specific configuration of each component will be described.

In this embodiment, the first circuit formed body is a flexible substrate 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. 1 is composed. 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.
Further, in this example, the second circuit formed body has a plurality of silver electrodes 2A formed of silver having a thickness of 3 μm on a glass having a thickness of 3 mm by screen printing and baking, and L / S = 50 μm / 50 μm. (See FIG. 3A).
Further, in this embodiment, the insulating adhesive resin is formed of a thermosetting epoxy resin sheet 3 having a width of 3 mm and a thickness of 35 μm, and using imitazole as a main curing agent.
In the present embodiment, the conductive particles are composed of the conductive particles 5 formed by applying a gold plating 5b having a thickness of 0.05 μm to the nickel particles 5a to have an average particle diameter of about 5 μm.
In this embodiment, the insulating barrier material layer is composed of a low-melting glass paste 4A containing a photosensitive resin as a binder.

Further, in this embodiment, the insulating sealing resin is composed of a photocurable insulating sealing resin 50 that is cured with an integrated light quantity of 2000 mJ / cm ² with a low-pressure 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 manufacturing method of the electrode junction structure concerning a present Example is demonstrated.
First, the low melting point glass paste 4A is applied to the surface of the glass substrate 2 where the silver electrode 2A is formed by screen printing to a thickness of about 10 μm (see FIG. 3B).
Next, after the low melting glass paste 4A is dried, exposure and etching are performed so that the low melting glass paste 4A having a width of about 25 μm remains between the adjacent silver electrodes 2A and 2A. At this time, the etching process time is controlled to set the overetching state.
Next, the low melting point glass paste 4A is heated to the melting point or higher. Thereby, the insulation barrier 4 is formed between the silver electrodes 2A and 2A (see FIG. 3C). This insulating barrier 4 contains a photosensitive resin.

Next, the epoxy resin sheet 3 in which the conductive particles 5 are dispersed is attached to the surface of the glass substrate 2 where the silver electrode 2A is formed (see FIG. 3D).
Next, the copper electrode 1A of the flexible substrate 1 and the silver electrode 2A of the glass substrate 2 are opposed to each other so that the epoxy resin sheet 3 is disposed between the flexible substrate 1 and the glass substrate 2 (FIG. 3E). reference).

Next, the epoxy resin sheet 3 is pressurized and heated to be melted through the flexible substrate 1 by the crimping tool 20 (for example, Bellofram cylinder manufactured by Fujikura Rubber Industry Co., Ltd.). As a result, the conductive particles 5 electrically joined to the respective copper electrodes 1A and the respective silver electrodes 2A are brought into contact with each other, and the epoxy resin sheet 3 is cured in that state, thereby the respective copper electrodes. 1A and each silver electrode 2A are electrically joined (refer FIG. 3F).
At this time, the heating time, pressing force, and pressing time by the crimping tool 20 are, for example, 180 ° C., 3 MPa, and 10 seconds.

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 (see FIG. 9). At this time, the coating amount of the insulating sealing resin 50 is set such that, for example, the thickness after photocuring is about 0.5 mm.
Thus, the manufacture of the electrode joint structure according to this example is completed.

  In the electrode bonded structure manufactured as described above, since the insulating barrier 4 is provided, the occurrence of migration can be suppressed even when the adjacent wiring electrodes have a narrow pitch of 0.1 mm. In addition, since the insulating particles 4 prevent the conductive particles 5 from agglomerating, the occurrence of short-circuit defects can be suppressed. 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.

  Since the electrode bonding method and the electrode bonding structure according to the present invention have the effect of preventing the occurrence of migration and corresponding to the narrow pitch between adjacent wiring electrodes, it is possible to form other circuits on the electrodes of the circuit forming body. The present invention is useful for a technique for bonding body electrodes using an insulating adhesive resin in which conductive particles are dispersed, particularly for a flat panel bonding technique represented by electrode bonding between a glass substrate and a flexible substrate.

It is a top view of the electrode junction structure concerning a 1st embodiment of the present invention. It is aa sectional drawing of FIG. 1A. It is bb sectional drawing of FIG. 1A. It is a partially expanded sectional view of FIG. 1C. It is sectional drawing of electroconductive particle. It is sectional drawing which shows the manufacturing method of the electrode junction structure concerning 1st Embodiment of this invention. It is sectional drawing which shows the process of following FIG. 3A. FIG. 3C is a cross-sectional view showing a step following FIG. 3B. It is sectional drawing which shows the process of following FIG. 3C. It is sectional drawing which shows the process of following FIG. 3D. It is sectional drawing which shows the process of following FIG. 3E. It is a flowchart which shows the manufacturing method of the electrode junction structure concerning 1st Embodiment of this invention. It is sectional drawing of the electrode junction structure concerning 2nd Embodiment of this invention. It is sectional drawing which shows the manufacturing method of the electrode junction structure concerning 2nd Embodiment of this invention. It is sectional drawing which shows the process of following FIG. 6A. FIG. 6B is a cross-sectional view showing a step following FIG. 6B. It is sectional drawing which shows the process of following FIG. 6C. It is sectional drawing which shows the process of following FIG. 6D. It is sectional drawing which shows the process of following FIG. 6E. It is a flowchart which shows the manufacturing method of the electrode junction structure concerning 2nd Embodiment of this invention. It is sectional drawing of the electrode junction structure concerning 3rd Embodiment of this invention. It is sectional drawing of the electrode junction structure concerning 4th Embodiment of this invention. It is sectional drawing which shows the modification of an insulation barrier. It is sectional drawing which shows the modification of an insulation barrier different from FIG. It is sectional drawing which shows the modification of another insulation barrier different from FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flexible substrate 1A 1st electrode 2 Glass substrate 2A 2nd electrode 3 Insulating adhesive resin 4,41 Insulation barrier 4A Insulation barrier material layer 5 Conductive particle 20 Crimping tool 21 Heating heater 22 Air cylinder 23 Motor 50 Insulation Sealing resin

Claims (20)

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 and bonds the two;
Located between the second electrodes adjacent to each other, at the interface between the second circuit forming body and the insulating adhesive resin, along the interface from one second electrode to the other second electrode A reverse path forming unit that forms a path having a component in a reverse direction from the other second electrode toward the one second electrode in a part of the path;
An electrode joint structure comprising:   The electrode junction structure according to claim 1, wherein the reverse path forming unit forms two paths having components in the reverse direction.   The electrode junction structure according to claim 1, wherein the reverse path forming portion is configured by a protrusion formed on the second circuit forming body.   The electrode bonding structure according to claim 3, wherein the protrusion extends in parallel to the second electrode.   The electrode bonding structure according to claim 5, wherein the protrusion forms a path having the component in the reverse direction by a surface located on the one second electrode side.   The electrode bonding structure according to claim 3, wherein the protrusion has a tapered cross-sectional shape that widens toward the first circuit forming body. The protrusion has a first protrusion forming part formed on the second circuit forming body, and a second protrusion forming part formed on the first protrusion forming member,
The surface of the second protrusion forming portion adjacent to the first protrusion forming portion is larger than the surface of the first protrusion forming portion adjacent to the second protrusion forming portion. 3. The electrode joint structure according to 3.   The electrode junction structure according to claim 3, wherein a height of the protrusion is lower than a total height of a height of the first electrode and a height of the second electrode.   The electrode bonding structure according to claim 3, wherein the protrusion is made of the same material as the second circuit forming body.   The electrode bonding structure according to claim 3, wherein the protrusion is made of a material that can be covalently bonded to the second circuit forming body.   The electrode projection structure according to claim 3, wherein the protrusion is made of an inorganic / organic composite material. The second circuit forming body is composed of a first material mainly composed of glass,
The electrode bonding structure according to claim 3, wherein the protrusion is made of a second material containing glass as a main component and having a melting point lower than that of the first material.   The electrode bonding structure according to claim 3, wherein the protrusion includes a photosensitive resin.   The electrode junction structure according to claim 1, wherein the reverse path forming portion is configured by a recess formed in the second circuit forming body.   The electrode junction structure according to claim 14, wherein the concave portion extends in parallel to the second electrode.   The electrode junction structure according to claim 15, wherein the recess forms a path having a component in the reverse direction by a surface located on the one second electrode side.   The electrode junction structure according to claim 14, wherein the recess has a tapered cross-sectional shape that widens in a direction away from the first circuit formation body.   The electrode bonding structure according to claim 1, wherein each of the second electrodes is made of silver.   The electrode bonding structure according to claim 1, wherein the insulating adhesive resin is a thermosetting resin.   Furthermore, the electrode joining structure according to any one of claims 1 to 19, further comprising an insulating sealing resin that covers the insulating adhesive resin so that the insulating adhesive resin is not exposed to the outside.

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