JP2013004202A - Anisotropic conductive material and connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anisotropic conductive material suppressed in generation of bubbles around conductive particles after an FPC has been subjected to thermal pressure bonding, thereby having a larger adhesive force.SOLUTION: An anisotropic conductive material contains a conductive particle, a binder resin and a solvent. The conductive particle has a 10% K value of a compressive elastic modulus at 140°C, which is 20-60% of a 10% K value of a compressive elastic modulus at 25°C, while the 10% K value of a compressive elastic modulus at 25°C is 2,300-4,500 N/mm.

Description

  The present invention relates to an anisotropic conductive material including a plurality of conductive particles, an anisotropic conductive material that can be used for electrical connection between electrodes of various connection target members, and the anisotropic conductive material. Related to the connection structure.

  An anisotropic conductive material is used for electrical connection between electrodes of various connection target members such as a flexible printed circuit board (FPC), a glass substrate, and a semiconductor chip. For example, in a touch panel, an electrode of a flexible printed board is electrically connected to another electrode by an anisotropic conductive material. In the anisotropic conductive material, a plurality of conductive particles are dispersed in ink or resin which is an adhesive component.

  As an example of the anisotropic conductive material, Patent Document 1 discloses a material that defines the elastic modulus of conductive particles. Specifically, it is an anisotropic conductive connection material that is placed between the connection terminal on the first substrate and the connection terminal on the second substrate, and is bonded to ensure the conduction between the two by thermocompression treatment. In the anisotropic conductive connecting material in which conductive particles are dispersed in an insulating adhesive, the elastic modulus of the conductive particles at the pressure bonding temperature is 60 to 90% of the elastic modulus at 25 ° C., and An anisotropic conductive connecting material characterized in that it is 200% or less of the elastic modulus of the first substrate at the pressure bonding temperature. "

  In recent years, due to the demand for a large number of wires and a narrow frame (screen enlargement, structure miniaturization) of the touch panel structure, the area of the bonding portion that bonds the FPC and other electrodes using an anisotropic conductive material is reduced. It is getting smaller. For this reason, a strong adhesive force is required by the anisotropic conductive material. However, the conventional anisotropic conductive material described in Patent Document 1 has a large repulsive force (restoring force of the shape) of the conductive particles after FPC thermocompression bonding, and bubbles are likely to be generated around the conductive particles. There is a problem. When such bubbles are generated, it causes a decrease in anisotropic conductivity and adhesiveness.

  Therefore, it is desired to develop an anisotropic conductive material having a larger adhesive force in which the generation of bubbles around the conductive particles after thermocompression bonding of the FPC is suppressed.

Japanese Patent No. 3541777

  An object of the present invention is to provide an anisotropic conductive material having a larger adhesive force in which the generation of bubbles around the conductive particles after thermocompression bonding of the FPC is suppressed.

  As a result of intensive studies to achieve the above object, the present inventor can achieve the above object when using conductive particles having a specific compressive modulus as the conductive particles contained in the anisotropic conductive material. As a result, the present invention has been completed.

That is, the present invention relates to the following anisotropic conductive material and connection structure.
1. An anisotropic conductive material containing conductive particles, a binder resin and a solvent,
The conductive particles have a compressive modulus 10% K value at 140 ° C. of 20 to 60% of a compressive modulus 10% K value at 25 ° C., and a compressive modulus 10% K value at 25 ° C. of 2300 to 2300. An anisotropic conductive material characterized by being 4500 N / mm ² .
2. The anisotropic conductive material according to Item 1, wherein the binder resin is at least one selected from the group consisting of amide resins, urethane resins, and chloroprene rubber.
3. Item 3. The anisotropic conductive material according to Item 1 or 2, wherein the solvent has a boiling point of 100 ° C or higher. 4). Item 4. The anisotropic conductive material according to any one of Items 1 to 3, wherein the conductive fine particles have a particle size of 5 to 50 µm.
5. Item 5. The anisotropic conductive material according to any one of Items 1 to 4, which is used for electrical connection of electrodes of a flexible printed board.
6). Item 6. The anisotropic conductive material according to any one of Items 1 to 5, which is used for a touch panel.
7). Item 7. The anisotropic conductive material according to any one of Items 1 to 6, comprising an inorganic filler having an average particle size of 0.01 to 5 µm.
8). Item 8. The anisotropic conductive material according to Item 7, wherein the inorganic filler contains talc.
9. A first connection target member, a second connection target member, and a connection part that electrically connects the first and second connection target members;
The connection structure in which the connection part is formed of the anisotropic conductive material according to any one of Items 1 to 8.

Hereinafter, the anisotropic conductive material and connection structure of the present invention will be described in detail.
1. Anisotropic conductive material The anisotropic conductive material of the present invention contains conductive particles, a binder resin and a solvent,
The conductive particles have a compressive modulus 10% K value at 140 ° C. of 20 to 60% of a compressive modulus 10% K value at 25 ° C., and a compressive modulus 10% K value at 25 ° C. of 2300 to 2300. 4500 N / mm ² .

  In the anisotropic conductive material of the present invention having the above characteristics, by using conductive particles having a specific compressive elastic modulus, the generation of bubbles around the conductive particles after thermocompression bonding of the FPC is suppressed. Even when the area of the bonding portion for bonding the FPC and the other electrode is small due to a request for narrowing the frame of the touch panel structure, good adhesive force is exhibited. Thereby, the connection structure which has favorable adhesiveness and anisotropic conductivity can be provided.

Hereinafter, each component constituting the anisotropic conductive material will be described.
(Conductive particles)
As the conductive particles, the compression modulus 10% K value at 140 ° C. is 20 to 60% of the compression modulus 10% K value at 25 ° C., and the compression modulus 10% K value at 25 ° C. is 2300 What is 4500 N / mm ² is used.

Specifically, the compression modulus 10% K value at 140 ° C. is preferably from 1300~1600N / mm ^2, more preferably 1400~1500N / mm ^2. Moreover, preferably the compression modulus 10% K value at 25 ° C. is 2400~4000N / mm ^2, more preferably 2500~3500N / mm ^2. The 10% K value of the compressive modulus at 140 ° C. may be 20 to 60% of the 10% K value of the compressive modulus at 25 ° C. Among them, it is preferably 30 to 50%.

By having the compression elastic modulus, the repulsive force (restoring force of the shape) of the conductive particles after the thermocompression bonding of the FPC can be suppressed, and the generation of bubbles around the conductive particles after the thermocompression bonding of the FPC can be suppressed. Even when the area of the bonded portion is small, good adhesive force can be obtained. In addition, the compression elastic modulus 10% K value in the present specification is a value measured using a micro compression tester (“Fischer Scope H-100” manufactured by Fischer), and a detailed measurement method is described in Examples below. This is explained in the column.

  The conductive particles are not particularly limited as long as they have the compression elastic modulus. Examples of the conductive particles include conductive particles obtained by coating the surfaces of organic particles, inorganic particles, organic-inorganic hybrid particles, metal particles, or the like with a metal layer (conductive layer), or substantially metal (conductive layer). ) And the like.

  Examples of the conductive layer include, but are not limited to, a gold layer, a silver layer, a copper layer, a nickel layer, a palladium layer, a metal layer containing tin, and an alloy layer of a different metal. The conductive layer may have a multilayer structure. The surface of the conductive layer may be covered with an insulating layer. In this case, when the connection target member is connected, the insulating layer between the conductive layer and the electrode is eliminated to ensure conductivity.

  In the present invention, as the conductive particles, a metal layer (conductive layer) is formed on the surface of the organic particles among the above, and an embodiment in which an insulating layer is formed as necessary is preferable. By employing such conductive particles, it is possible to suppress damage to the electrodes and further improve the conduction reliability between the electrodes.

  Although the particle diameter of electroconductive particle is not limited, 5-50 micrometers is preferable and 10-30 micrometers is more preferable.

  The “particle diameter” of the conductive particles indicates the number average particle diameter. The average particle diameter of the conductive particles can be obtained by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value.

Although the content of the conductive particles in the anisotropic conductive material is not particularly limited, the content of the conductive particles in 100% by weight of the anisotropic conductive material is preferably 0.1% by weight or more, more preferably 0. .5% by weight or more, preferably 20% by weight or less, more preferably 10% by weight or less. When the content of the conductive particles is within such a range, the conductive particles can be easily arranged between the upper and lower electrodes to be connected. Moreover, it becomes difficult to connect electrically between the adjacent electrodes which should not be connected via several electroconductive particle. That is, a short circuit between adjacent electrodes can be further prevented.
(Binder resin)
The binder resin is not particularly limited, and binder resins used for known anisotropic conductive materials can be widely used. Among these known binder resins, at least one selected from the group consisting of amide resins, urethane resins and chloroprene rubbers is particularly preferable.

  As the amide resin, it is preferable to use a polyamide elastomer, which is a polyamide elastomer having a polyamide skeleton as a hard segment and at least one of a polyether ester skeleton and a polyester skeleton as a soft segment. preferable. As a commercial product of such a polyamide elastomer, TPAE series manufactured by Fuji Kasei Kogyo Co., Ltd. can be mentioned. Among these, “TPAE-31”, “TPAE-32”, and “TPAE-33” manufactured by Fuji Kasei Kogyo Co., Ltd. are preferably used as commercial products of the polyamide elastomer.

  The urethane resin is generally synthesized using a highly reactive isocyanate compound as a hard segment component, a chain extender having active hydrogen in the molecule as a soft segment component, and a polyol compound. By combining these materials, polyurethane resins having various characteristics can be obtained. By freely combining the hard segment component and the soft segment component, it is possible to freely synthesize from a soft one to a hard one.

Examples of the isocyanate compound include diphenylmethane-4,4′-diisocyanate (MDI) and isophorone diisocyanate (IPDI). Isocyanate compounds other than these may be used.

  Examples of the chain extender include glycol compounds and amine compounds. The molecular weight of the chain extender is preferably 1000 or less.

  Examples of the polyol compound include polyester polyols and polyether polyols. Examples of the polyester polyol include polypropylene adipate, polyhexamethylene carbonate, and poly-ε-caprolactone. Examples of the polyether polyol include polytetramethylene glycol and polyethylene glycol.

  There are many commercially available polyurethane resins. Examples of commercially available polyurethane resins include the Milactone series manufactured by Nippon Polyurethane Industry Co., Ltd., the Rezamin series manufactured by Dainichi Seika Co., Ltd., and the Pandex series manufactured by DIC Corporation.

  In addition to the amide resin, urethane resin, and chloroprene rubber, for example, MgO-adsorbed phenol can be used as the binder resin.

  The MgO-adsorbed phenol can be easily obtained by, for example, dispersing MgO powder in a phenol resin solution and stirring it at room temperature for 1 day, and then removing excess MgO. A part of the adsorbed MgO adsorbs to the carboxyl group and the phenolic hydroxyl group, and physical crosslinks (coordination bonds) are formed as the entire MgO adsorbed phenol. Unlike chemical crosslinking, this physical crosslinking is reversible by heat, and thus can exhibit high cohesion while maintaining flexibility.

Although the content of the binder resin in the anisotropic conductive material is not particularly limited, the content of the binder resin is preferably 30% by weight or more in 100% by weight of the anisotropic conductive material (solid content conversion: excluding the solvent). More preferably, it is 50% by weight or more, preferably 95% by weight or less, more preferably 90% by weight or less. In the anisotropic conductive material, various fillers and the like are often blended so as to be suitable for screen printing. Therefore, when the content of the binder resin is too large, other properties other than adhesiveness tend to be deteriorated. is there.
(solvent)
The solvent is not particularly limited. By using a solvent, the viscosity of the anisotropic conductive material can be easily adjusted. The solvent preferably has a boiling point of 100 ° C. or higher, and examples thereof include benzyl alcohol, isophorone, dimethylformamide, methyl cellosolve, toluene, cyclohexanone and the like. These solvents can be used alone or in combination of two or more.

  The solvent may be added as a liquid in which the binder resin is dispersed or dissolved, or may be added as a liquid in which conductive particles are dispersed. Further, in the manufacturing process of the anisotropic conductive material, the solvent may be added depending on the purpose of adjusting the viscosity.

The content of the solvent is appropriately adjusted in consideration of the dispersion or solubility of other components, the viscosity of the anisotropic conductive material, and the like. In 100% by weight of the anisotropic conductive material, the content of the solvent is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, still more preferably 1% by weight or more, preferably 85% by weight or less, and more. Preferably it is 75 weight% or less.
(Other ingredients)
In addition to the above components, the anisotropic conductive material of the present invention includes a thermosetting compound, a curing agent, a curing accelerator, a photocurable compound, a photopolymerization initiator, an inorganic filler, an organic filler, a storage stabilizer, an ion Scavenger,
A silane coupling agent, a tackifier, an antifoaming agent, a dispersant, a thixotropy adjusting agent, a leveling agent and the like may further be included.

  Of the above-mentioned other components, inorganic fillers are preferably used. By using an inorganic filler, the viscosity and thixotropy as an anisotropic conductive material can be arbitrarily adjusted, and cohesive force and stress relaxation properties can be expressed. Examples of the inorganic filler include oxides such as silica, alumina, titanium oxide, zirconia, zinc oxide, magnesium oxide and iron oxide, carbonates such as calcium carbonate, magnesium carbonate and zinc carbonate, aluminum silicate and magnesium silicate. Silicates such as calcium silicate, kaolin, clay, talc, mica, zeolite and sericite, hydroxides such as aluminum hydroxide and magnesium hydroxide, sulfates such as calcium sulfate, barium sulfate and calcium sulfite, or Examples thereof include sulfites, nitrides such as boron nitride and silicon nitride, titanates such as potassium titanate and barium titanate, and the like. Furthermore, examples of the inorganic filler include dawsonite, carbon black, and silicon carbide. The said inorganic filler can be used by 1 type (s) or 2 or more types.

  From the viewpoint of further improving the adhesiveness of the anisotropic conductive material, the inorganic filler preferably contains talc.

  The average particle size of the inorganic filler is preferably 0.01 to 5 μm. When the average particle size of the inorganic filler is within the above range, stress relaxation properties are effectively expressed, and the adhesiveness of the anisotropic conductive material is further enhanced. From the viewpoint of further enhancing the adhesion of the anisotropic conductive material, the average particle size of the inorganic filler is more preferably 3 μm or less.

  The “average particle diameter” is a cumulative 50% particle diameter (Median diameter) obtained from a particle size distribution measurement result measured by a laser diffraction particle size distribution measuring apparatus.

  Moreover, it is preferable that the said inorganic filler is surface-treated. A conventionally known method can be employed as the surface treatment method.

The content of the inorganic filler is preferably 5 parts by weight or more, preferably 150 parts by weight or less, more preferably 100 parts by weight or less with respect to 100 parts by weight of the binder resin. When the content of the inorganic filler is within the above range, an effect of improving the adhesiveness of the anisotropic conductive material can be effectively obtained, and the dispersion state of the inorganic filler is improved, resulting in a decrease in storage stability. It is difficult for problems such as these to occur.
(Details and applications of anisotropic conductive materials)
The anisotropic conductive material of the present invention is preferably a paste-like or film-like anisotropic conductive material, preferably a paste. The paste-like anisotropic conductive material is an anisotropic conductive paste. The film-like anisotropic conductive material is an anisotropic conductive film.

  When an anisotropic conductive material of the present invention is used to electrically connect an electrode of a flexible printed circuit board (FPC) to another electrode to obtain a connection structure such as a touch panel, the conductivity after thermocompression bonding of the FPC The generation of bubbles in the vicinity of the conductive particles is suppressed, and a good adhesive force can be obtained even when the area of the bonding portion where the FPC and another electrode are bonded is small due to a request for narrowing the frame of the touch panel structure.

The anisotropic conductive material of the present invention is preferably an anisotropic conductive material for a touch panel. That is, the anisotropic conductive material of the present invention is preferably an anisotropic conductive material for a touch panel used for electrical connection of FPC electrodes. In the touch panel, the anisotropic conductive material is exposed to a high temperature environment. In the anisotropic conductive material of the present invention, the repulsive force (the shape restoring force) of the conductive particles after thermocompression bonding of the FPC is suppressed. Therefore, even if the anisotropic conductive material is exposed to high temperatures, Adhesiveness between the isotropic conductive material and the connection target member can be favorably maintained.
2. Connection Structure The anisotropic conductive material of the present invention can be used for bonding various connection target members. The anisotropic conductive material is suitably used for obtaining a connection structure in which the first and second connection target members are electrically connected.

  FIG. 1 is a cross-sectional view schematically showing an example of a connection structure using an anisotropic conductive material according to an embodiment of the present invention.

  A connection structure 1 shown in FIG. 1 includes a first connection target member 2, a second connection target member 4, and a connection part 3 connecting the first and second connection target members 2 and 4. Prepare. The connection part 3 is formed of an anisotropic conductive material including the conductive particles 5.

  A plurality of electrodes 2 b are provided on the upper surface 2 a of the first connection target member 2. A plurality of electrodes 4 b are provided on the lower surface 4 a of the second connection target member 4. The electrode 2b and the electrode 4b are electrically connected by one or a plurality of conductive particles 5. Therefore, the first and second connection target members 2 and 4 are electrically connected by the conductive particles 5.

  The connection between the electrodes 2b and 4b is usually performed after the first connection target member 2 and the second connection target member 4 are overlapped with each other via the anisotropic conductive material so that the electrodes 2b and 4b face each other. When the anisotropic conductive material is cured, it is performed by applying pressure. Although the conductive particles 5 are compressed by the pressurization, in the present invention, the conductive particles have a specific compression elastic modulus, thereby suppressing the repulsive force (the restoring force of the shape) of the conductive particles after the pressurization. In addition, the generation of bubbles around the conductive particles after pressurization is suppressed.

  Specifically, as the connection structure, an electronic component chip such as a semiconductor chip, a capacitor chip or a diode chip is mounted on a circuit board, and the electrode of the electronic component chip is connected to an electrode on the circuit board. Examples include electrically connected structures. As a circuit board, various printed circuit boards, such as various printed circuit boards, such as FPC, a glass substrate, or a board | substrate with which metal foil was laminated | stacked, are mentioned. The first and second connection target members are preferably electronic components or circuit boards.

  At least one of the first and second connection target members is preferably an FPC. The connection structure is preferably a touch panel.

  The anisotropic conductive material of the present invention employs conductive particles having a specific compressive elastic modulus, thereby suppressing the generation of bubbles around the conductive particles after thermocompression bonding of the FPC. Even when the area of the bonding portion for bonding the FPC and another electrode is small due to the demand for narrowing the frame, good adhesive force is exhibited. Thereby, the connection structure which has favorable adhesiveness and anisotropic conductivity can be provided.

It is a front sectional view showing typically the connection structure using the anisotropic conductive material concerning one embodiment of the present invention. In an Example and a comparative example, it is a schematic diagram which shows the flexible printed circuit board (FPC) used for the measurement of adhesive force. In an Example and a comparative example, it is a schematic diagram which shows the sample for a measurement used for the measurement of T-type peeling strength. In an Example and a comparative example, it is a limit sample used as the judgment standard at the time of judging the presence or absence of bubble generation.

  The present invention will be specifically described below with reference to examples and comparative examples. However, the present invention is not limited to the examples.

Examples 1-5 and Comparative Examples 1-5
<< Production of connection structure >>
(1) The components of each Example and each Comparative Example shown in Table 1 below were kneaded for 3 minutes at 2000 revolutions in a revolving vacuum mixer “Awatori Nertaro” to prepare an anisotropic conductive paste.
(2) The compressive modulus 10% K value (N / mm ² ) at 25 ° C. and the pressure bonding temperature (140 ° C.) of the conductive particles used in each example and each comparative example is shown in Table 2.
(3) The compression elastic modulus 10% K value of the conductive particles was measured as follows. Using a micro-compression tester, the conductive particles are compressed under the conditions of a compression rate of 2.6 (mN / sec) and a maximum test load of 10 g with the end face of a diamond cylinder having a diameter of 50 um. The load value (N) and compression displacement (mm) at this time are measured. From the measured value obtained, the compression modulus can be obtained from the following formula. As the micro compression tester, for example, “Fischer Scope H-100” manufactured by Fischer was used.

K value (N / mm ² ) = (3/2 ^1/2 ) · F · S ⁻³ / ² · R ^−1/2
F: Load value when conductive particles are compressed by 10% (N)
S: Compression displacement when conductive particles are compressed by 10% (N)
R: radius of conductive particles (mm)
(4) The compression elastic modulus 10% K value (%) at 140 ° C. with respect to the compression elastic modulus 10% K value at 25 ° C. is shown in Table 2.
(5) An anisotropic conductive paste was applied to a flexible substrate on which a 18 μm-thick copper wiring was formed on a polyimide substrate, and 5 μm-thick Ni and 0.05 μm-thick Au were deposited on the wiring. A 100 mesh (material stainless steel) plate was used as the coating method, and the obtained anisotropic conductive material was screen-printed so that the thickness after drying was 20 to 25 μm. Next, drying was performed in a hot air drying oven at 110 ° C. for 10 minutes. Then, using a constant heater type crimping machine (Ohashi Seisakusho: BD-03SDSS), the flexible printed circuit board and the PET substrate on which the 1 mm pitch Ag paste electrode shown in FIG. Bonding was performed for 15 seconds under the conditions of a pressure bonding temperature of 140 ° C. and a pressure of 294.2 N / cm ² to obtain a connection structure shown in FIG.

≪Characteristic evaluation≫
With the obtained connection structure, initial adhesive strength, adhesive strength after high-temperature and high-humidity test, initial resistance value, and resistance value after high-temperature and high-humidity test were measured. The measuring method is as follows.

Initial adhesion force As shown in FIG. 3, using a static material tester (“EZ-Graph” manufactured by Shimadzu Corporation), the obtained adhesive force measurement sample was subjected to T-type peeling at a pulling speed of 50 mm / min. A test was conducted. The maximum value of the obtained T-type peel strength was taken as the measured value of adhesive force. As shown in FIG. 3, it peeled in the direction shown by the arrow, and the adhesive force was measured.

After the high-temperature and high-humidity test, the bonded structure was left in a 60C, 95% RH environment for 500 hours, and then the adhesive force was measured by the above method.

The wiring resistance value of the initial resistance value connection structure was measured with a resistance measuring device (Iwasaki Tsushinki VOAC7521).

After the high temperature and high humidity test, the resistance value connection structure was left in a 60 C, 95% RH environment for 500 hours, and then the resistance value was measured by the above method.

Presence / absence of bubbles on the bonded surface after pressure bonding The presence or absence of bubbles on the bonded surface after pressure bonding was determined using the obtained connection structure. In the determination method, an anisotropic conductive paste was applied to a flexible substrate on which a 9 μm-thick copper wiring was formed on a polyimide substrate, and 5 μm-thick Ni and 0.05 μm-thick Au were deposited on the wiring. As a coating method, a drying method, and a pressure bonding method, a flexible substrate and ITO glass were bonded to each other for 15 seconds under the conditions of a pressure bonding temperature of 140 ° C. and a pressure of 294.2 N / cm ² to obtain a connection structure.

The obtained connection structure was confirmed visually from the top surface of the ITO glass. When bubbles are generated, bubbles are observed around the pressed particles. The presence or absence of the generation of bubbles was determined using the limit sample shown in FIG. 4 as a criterion.

  The results of each characteristic evaluation are shown in Table 2 below.

≪Discussion≫
As can be seen from Table 2, when the compressive modulus 10% K value of the conductive particles at the pressure bonding temperature is 60% or more of the compressive modulus 10% K value at 25 ° C., the adhesive strength decreases after the high temperature and high humidity test. It is noticeable. Within 20% of the initial value as the allowable range of the decrease rate is a normal test pass standard.

  In addition, when the compressive modulus 10% K value of the conductive particles at the pressure bonding temperature is 60% or more and 20% or less of the compressive modulus 10% K value at 25 ° C., the connection resistance decreases after the high temperature and high humidity test ( (Increase in resistance value) is noticeable. Within 20% of the initial value as the allowable range of the decrease rate is a normal test pass standard.

  In addition, when the compression elastic modulus 10% K value of the conductive particles at the pressure bonding temperature is 60% or more of the compression elastic modulus 10% K value at 25 ° C., adhesive surface bubbles after the pressure bonding are observed. When this phenomenon is observed, it causes an increase in the connection resistance due to corrosion of the wiring portion over time and a decrease in the adhesive strength after aging.

Even if the compressive modulus 10% K value of the conductive particles at the pressure bonding temperature is in the range of 20 to 60% of the compressive modulus 10% K value at 25 ° C., the compressive modulus 10% K value at 25 ° C. is 2300 (N / Mm ² ) or less or 4500 (N / mm ² ), the initial resistance value is significantly reduced. Moreover, in the case of 4500 (N / mm < ² >) or more, the fall of resistance value after a high temperature, high humidity test is also large. In the case of 2300 (N / mm ² ) or less, the above phenomenon occurred due to the destruction of the conductive particles, and in the case of 4500 (N / mm ² ) or more, the contact area to the connection terminal decreased.

  In addition to polyamide resin, binder resin used urethane resin and chloroprene rubber, there was no decrease in adhesive strength and connection resistance value.

Therefore, in order to improve the connection reliability of the anisotropic conductive connection material, the elastic modulus at the pressure bonding temperature as the conductive particles is in the range of 20 to 60% of the elastic modulus at 25 ° C. and K of 10% compression at 25 ° C. The value needs to be 2300-4500 (N / mm ² ).

DESCRIPTION OF SYMBOLS 1 ... Connection structure 2 ... 1st connection object member 2a ... Upper surface 2b ... Electrode 3 ... Connection part 4 ... 2nd connection object member 4a ... Lower surface 4b ... Electrode 5 ... Electroconductive particle 51 ... Electrode with Ag paste 52 ... PET substrate

Claims (9)

An anisotropic conductive material containing conductive particles, a binder resin and a solvent,
The conductive particles have a compressive modulus 10% K value at 140 ° C. of 20 to 60% of a compressive modulus 10% K value at 25 ° C., and a compressive modulus 10% K value at 25 ° C. of 2300 to 2300. An anisotropic conductive material characterized by being 4500 N / mm ² .   The anisotropic conductive material according to claim 1, wherein the binder resin is at least one selected from the group consisting of an amide resin, a urethane resin, and a chloroprene rubber.   The anisotropic conductive material according to claim 1, wherein the solvent has a boiling point of 100 ° C. or higher.   The anisotropic conductive material according to claim 1, wherein the conductive particles have a particle diameter of 5 to 50 μm.   The anisotropic conductive material in any one of Claims 1-4 used for the electrical connection of the electrode of a flexible printed circuit board.   The anisotropic conductive material according to any one of claims 1 to 5, which is used for a touch panel.   The anisotropic conductive material in any one of Claims 1-6 containing the inorganic filler whose average particle diameter is 0.01-5 micrometers.   The anisotropic conductive material according to claim 7, wherein the inorganic filler contains talc. A first connection target member, a second connection target member, and a connection part that electrically connects the first and second connection target members;
The connection structure in which the said connection part is formed with the anisotropic conductive material in any one of Claims 1-8.

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