WO2012137335A1

WO2012137335A1 - Circuit connection material and use thereof, and connecting structure and method for producing same

Info

Publication number: WO2012137335A1
Application number: PCT/JP2011/058813
Authority: WO
Inventors: 孝中澤; 小林　宏治
Original assignee: 日立化成工業株式会社
Priority date: 2011-04-07
Filing date: 2011-04-07
Publication date: 2012-10-11

Abstract

Provided is a circuit connection material containing an adhesive composition and insulator-coated conductive particles, that subsequent to curing has an elasticity of 0.5-1.0 GPa at 40ºC. The insulator-coated conductive particles are provided with conductive particles that have a base particle and a metal plating layer covering at least part of the base particle surface, and fine insulating particles covering at least part of the conductive particle surface. The circuit connection material exhibits a compressive elastic modulus of 800-3500 N/mm² when the conductive particles undergo compressive deformation by 20% of the particle diameter.

Description

Circuit connection material and use thereof, and connection structure and manufacturing method thereof

The present invention relates to a circuit connection material and use thereof, and a connection structure and a manufacturing method thereof.

The method of mounting a liquid crystal driving IC on a glass panel for liquid crystal display can be roughly divided into two types: COG (Chip-on-Glass) mounting and COF (Chip-on-Flex) mounting. In COG mounting, an IC for liquid crystal is directly bonded onto a glass panel using an anisotropic conductive adhesive containing conductive particles. On the other hand, in COF mounting, a liquid crystal driving IC is bonded to a flexible tape having metal wiring, and these are bonded to a glass panel using an anisotropic conductive adhesive containing conductive particles. The anisotropic conductivity here means conducting in the pressurizing direction and maintaining insulation in the non-pressurizing direction.

However, in recent years, gold bumps, which are circuit electrodes of liquid crystal driving ICs, have been narrowed in pitch and area in order to increase the definition of liquid crystal displays, and as a result, the conductive particles of anisotropic conductive adhesive have been reduced. There is a problem that a short circuit occurs between adjacent circuit electrodes. This tendency is particularly noticeable in COG, which requires a narrow pitch gold bump. When conductive particles flow out between adjacent circuit electrodes, the number of conductive particles in the anisotropic conductive adhesive captured between the gold bump and the glass panel decreases, and the connection resistance between the opposing circuit electrodes increases. There was a problem of poor connection.

Therefore, as a method for solving these problems, as shown in Patent Document 1, by forming an insulating adhesive on at least one side of the anisotropic conductive adhesive, the bonding quality in COG mounting or COF mounting is improved. A method for preventing the reduction and a method for covering the entire surface of the conductive particles with an insulating film as exemplified in Patent Document 2 have been proposed.

JP-A-8-279371 Japanese Patent No. 2779409

However, in the method of forming the insulating adhesive layer on one side of the anisotropic conductive adhesive layer as in Patent Document 1, when the bump area is less than 3000 μm ² , stable conductivity is obtained between the facing circuit electrodes. Therefore, when sufficient conductive particles are included in the anisotropic conductive adhesive composition, the insulation between adjacent electrodes tends to be insufficient. In addition, as in Patent Document 2, the method of covering the entire surface of the conductive particles with an insulating coating can increase the insulation between adjacent electrodes, but the conductivity between the facing circuit electrodes is low. There is still room for improvement.

Therefore, the present invention has a sufficiently high adhesiveness in the connection of circuit electrodes with a narrow pitch and a narrow area, and also has insulation between adjacent circuit electrodes and conduction between opposing circuit electrodes on the same substrate. It is an object of the present invention to provide a circuit connection material having excellent properties, its use, a connection structure using the circuit connection material, and a method for manufacturing the connection structure.

In order to achieve the above object, the present invention provides a circuit connecting material comprising an adhesive composition and insulating coated conductive particles, wherein the elastic modulus at 40 ° C. after curing is 0.5 to 1.0 GPa. Insulating coated conductive particles comprising conductive particles having base particles and a metal plating layer covering at least a part of the surface of the base particles; insulating fine particles covering at least a part of the surface of the conductive particles; And a circuit connecting material having a compressive elastic modulus of 800 to 3500 N / mm ² at 20% compression deformation of the particle diameter of the conductive particles.

Such a circuit connection material has sufficiently high adhesiveness in connection of circuit electrodes with a narrow pitch and a small area, and also has insulation between adjacent circuit electrodes and conduction between opposing circuit electrodes on the same substrate. Excellent in properties.

The present inventors infer the reason why such an effect is obtained as follows. That is, by containing insulating coated conductive particles having a predetermined configuration, the electrodes can be connected to each other via the metal plating layer by eliminating the insulating adhesive component between the opposing electrodes, and adjacent circuit electrodes It is considered that the insulating property can be maintained by the presence of insulating fine particles covering the conductive particles. And it thinks that the adhesive force between the circuits to connect can be kept high by adjusting the elasticity modulus of a circuit connection material to a predetermined range.

From the viewpoint of further improving the insulation between adjacent circuits, the average particle size of the conductive particles is preferably 5.0 μm or less.

The present invention also provides a first circuit member having a first substrate and a first circuit electrode formed on the main surface thereof, and a second substrate and a second circuit formed on the main surface thereof. A second circuit electrode, wherein the second circuit electrode and the first circuit electrode are arranged to face each other, and the second circuit electrode is electrically connected to the first circuit electrode. Provided is a connection structure including a circuit member and a connection portion interposed between the first circuit member and the second circuit member, wherein the connection portion is a cured product of the circuit connection material of the present invention.

Such a connection structure has sufficiently high adhesiveness, and has a connection portion that is excellent in insulation between circuit electrodes adjacent to each other on the same substrate and in electrical conductivity between circuit electrodes facing each other, and therefore has excellent connection reliability. It becomes.

The present invention also includes an adhesive composition and insulating coated conductive particles, and has an elastic modulus of 0.5 to 1.0 GPa at 40 ° C. after curing. And a conductive particle having a metal plating layer covering at least a part of the surface of the substrate particle, and insulating fine particles covering at least a part of the surface of the conductive particle, and having a particle diameter of 20 of the conductive particle. Use of a material having a compressive elastic modulus at% compressive deformation of 800 to 3500 N / mm ² for circuit connection is provided.

By using such a material for circuit connection, it is possible to exhibit sufficiently high adhesiveness in the connection of circuit electrodes having a narrow pitch and a small area, and insulation between adjacent circuit electrodes on the same substrate. In addition, it is possible to ensure excellent conductivity between circuit electrodes facing each other.

When such a material is used for circuit connection, the average particle diameter of the conductive particles is preferably 5.0 μm or less from the viewpoint of further improving the insulation between adjacent circuits.

The present invention further includes a first circuit member having a first substrate and a first circuit electrode formed on the main surface thereof, and a second circuit formed on the second substrate and the main surface thereof. A step of obtaining a laminate by interposing the circuit connection material of the present invention between a pair of circuit members having a second circuit member having an electrode, and heating and pressurizing the laminate to cure the circuit connection material Thus, a connection part is formed between the pair of circuit members so that the first circuit electrode and the second circuit electrode arranged opposite to each other are electrically connected to each other. A method for manufacturing a connection structure.

With such a manufacturing method, it is possible to form a connection portion having sufficiently high adhesiveness and excellent insulation between adjacent circuit electrodes and excellent conductivity between opposing circuit electrodes on the same substrate. A connection structure having excellent connection reliability can be manufactured.

According to the present invention, in the connection of circuit electrodes having a narrow pitch and a small area, the circuit electrode has sufficiently high adhesiveness, insulation between adjacent circuit electrodes on the same substrate, and conduction between opposing circuit electrodes. It is possible to provide a circuit connection material having excellent properties and use thereof, a connection structure using the circuit connection material, and a method for manufacturing the connection structure.

It is sectional drawing which shows one Embodiment of a circuit connection material. It is an external view of the insulation coating electrically-conductive particle which concerns on this embodiment. It is sectional drawing of the insulation coating electrically-conductive particle which concerns on this embodiment. It is sectional drawing which shows one Embodiment of a connection structure.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. However, the present invention is not limited to the following embodiments. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

The circuit connection material of the present invention is a circuit connection material containing an adhesive composition and insulating coated conductive particles, and has an elastic modulus at 40 ° C. of 0.5 to 1.0 GPa after curing, and has an insulating property. The coated conductive particles comprise base particles and conductive particles having a metal plating layer that covers at least part of the surface of the base particles, and insulating fine particles that cover at least part of the surface of the conductive particles, and The compressive elastic modulus at 20% compression deformation of the particle diameter of the conductive particles is 800 to 3500 N / mm ² .

The circuit connection material according to the present embodiment is an adhesive used for electrically connecting circuit electrodes. FIG. 1 is a cross-sectional view showing an embodiment of a circuit connecting material. A circuit connection material 50 shown in FIG. 1 is composed of a resin layer 12 made of an adhesive composition and a plurality of insulating coated conductive particles 10 dispersed in the resin layer 12, and has a film shape.

Hereinafter, materials constituting the circuit connection material 50 will be described.

(Insulation coated conductive particles)
FIG. 2 is an external view of the insulating coated conductive particles according to the present embodiment, and FIG. 3 is a cross-sectional view of the insulating coated conductive particles according to the present embodiment. The insulating coated conductive particles 10 include conductive particles 8 having base particles 2 and a metal plating layer 4 covering at least a part of the surface of the base particles, and insulating properties covering at least a part of the surfaces of the conductive particles 8. It comprises fine particles 6.

The average particle diameter of the conductive particles 8 needs to be smaller than the minimum interval between the electrodes adjacent to each other on the same substrate from the viewpoint of ensuring insulation. In addition, when there is a variation in the height of the electrodes on the same substrate, the average particle diameter of the conductive particles 8 is preferably larger than the variation. From such a viewpoint, the average particle diameter of the conductive particles 8 is preferably 5.0 μm or less, more preferably 1.0 to 5.0 μm, and preferably 2.0 to 4.0 μm. Further preferred.

The conductive particles 8 include base material particles 2 and a metal plating layer 4 that covers at least a part of the surface of the base material particles 2. The average particle size of the substrate particles 2 is preferably 4.0 μm or less, more preferably 1.0 to 4.0 μm, and even more preferably 2.0 to 3.7 μm. When the average particle diameter of the substrate particles 2 is 1.0 μm or more, the conductive particles easily absorb the height variation of the chip bumps during mounting, and the conductivity is improved. When the thickness is 4.0 μm or less, the insulation resistance does not decrease and a short circuit defect is less likely to occur.

The base particle 2 is a resin particle made of resin. Since the substrate particles are resin particles, the contact area between the conductive particles and the electrode can be increased by deformation due to heating and pressurization. Although it does not specifically limit as resin used for a base particle, An acrylic resin, an olefin resin, a styrene resin, a benzoguanamine resin, a silicone resin, a polybutadiene resin, or these copolymers are mentioned, and what crossed these is used. Also good. Among these, crosslinked styrene particles are preferable from the viewpoint of easily adjusting the hardness of the conductive particles 8.

The metal plating layer 4 covering the surface of the substrate particles 2 may have a single layer structure, but it is preferable that at least a part of the metal plating layer 4 has a multilayer structure composed of a plurality of layers. In the case of a multilayer structure, the outermost layer is preferably a gold layer from the viewpoint of corrosion resistance and conductivity, and the portion where the gold layer is the surface is more preferably 60% or more of the entire surface of the conductive particles 8. Moreover, it is preferable that a metal plating layer contains a gold layer and a nickel layer, and at least one part of this gold layer is provided outside the nickel layer. Further, the atomic ratio of nickel atoms to gold atoms on the surface of the conductive particles 8 is preferably 70% or less. The atomic abundance ratio is measured by an X-ray photoelectron spectrometer. By making the surface of the conductive particles 8 have the above-described configuration, the insulating fine particles 6 are difficult to peel from the conductive particles 8, and the insulation between adjacent circuits can be improved.

In addition to gold and nickel, the metal used for the metal plating layer 4 covering the surface of the base particle 2 is silver, copper, platinum, zinc, iron, palladium, tin, chromium, titanium, aluminum, cobalt, germanium, A metal such as cadmium, ITO, solder, or the like can be used.

Examples of the method for coating the substrate particles 2 with the metal plating layer 4 include electroless plating, displacement plating, electroplating, and sputtering. The thickness of the metal plating layer is not particularly limited, but is preferably in the range of 0.005 to 1.0 μm, and more preferably in the range of 0.01 to 0.3 μm. If the thickness of the metal plating layer is less than 0.005 μm, there is a tendency to cause poor conduction, and if it exceeds 1.0 μm, the cost is increased.

It is important that the conductive particles 8 have a specific hardness in order to ensure good conduction during thermocompression bonding. Conductive particles 8, the compression modulus when the particle diameter is 20% compressive deformation (hereinafter, also referred to as "20% K value") of 800 ~ 3500N / mm ² that is 1000 ~ 3000N / mm ² Is preferable, and more preferably 1100 to 2800 N / mm ² .

When the 20% K value of the conductive particles 8 is less than 800 N / mm ² , the binder resin (adhesive composition) between the conductive particles and the electrode terminals is not excluded because of being too soft, and the restoring force is low, so that the substrate or bump It is difficult to absorb the variation in height, and the continuity becomes unstable. On the other hand, if the 20% K value of the conductive particles 8 exceeds 3500 N / mm ² , the conductive particles are too hard and cannot be flattened at the time of thermocompression bonding, and the contact area becomes narrow, and the conduction tends to become unstable.

The 20% K value in this embodiment is a smooth end face of a square column with a side of 50 μm using a micro compression tester (trade name “Fisherscope H100” manufactured by Fisher, Inc.), and the conductive particles are compressed at a compression speed of 0.33 mN / It can be determined by compressing at a maximum test load of 40 mN. The measurement is performed in a room temperature environment.

By appropriately changing the type of resin particles constituting the base particles, the cross-linking density when the base particles are cross-linked resin particles, the type of metal constituting the metal plating layer 4 and the like, a predetermined range of 20 Conductive particles 8 having a% K value can be obtained. Also, conductive particles having 20% K value of various grades are available from Sekisui Chemical Co., Ltd.

In the conductive particles 8, it is desirable that the load F (mN) at the time of 20% deformation and the particle diameter R (μm) satisfy the relationship represented by the following formula (1).
0.1 ≦ F / R <0.3 (1)

When F / R is less than 0.1, the insulating coated conductive particles 10 are too flat at the time of circuit connection, and the elastic recovery of the insulating coated conductive particles 10 is likely to be lost. On the other hand, when F / R is 0.3 or more, the insulating coated conductive particles 10 are not easily flattened, and it is difficult to obtain a sufficient contact area with respect to the circuit electrode, so that the connection resistance tends to increase.

If the conductive particles 8 have a functional group on the surface, the conductive particles 8 are easily covered with the insulating fine particles 6. From the viewpoint of improving the bonding strength with the insulating fine particles 6, the functional group is preferably at least one selected from a hydroxyl group, a carboxyl group, an alkoxy group, and an alkoxycarbonyl group. The formation of these functional groups on the surface of the conductive particles 8 can be confirmed by an analysis technique such as X-ray electron spectroscopy or time-of-flight secondary ion mass spectrometry.

The functional group can be formed by attaching or bonding a compound having a group that forms a coordinate bond to the surface of the conductive particle 8 and the functional group to the surface of the conductive particle 8. Examples of the group that forms a coordinate bond include a mercapto group, a sulfide group, or a disulfide group that forms a coordinate bond with gold when the surface of the conductive particle 8 is made of a gold layer. Therefore, it is preferable that a compound having a mercapto group, sulfide group or disulfide group and a functional group adheres to or binds to the surface of the conductive particles 8. Examples of such a compound having a mercapto group, sulfide group or disulfide group and a functional group include mercaptoacetic acid, 2-mercaptoethanol, methyl mercaptoacetate, mercaptosuccinic acid, thioglycerin and cysteine.

As a specific method for forming a functional group on the surface of the conductive particles 8, for example, the above-mentioned compound such as mercaptoacetic acid is dissolved in an organic solvent such as methanol or ethanol at about 10 to 100 mmol / L, and the solution is dissolved in the solution. A method of dispersing the conductive particles 8 can be mentioned.

The insulating fine particles 6 are preferably inorganic oxide fine particles from the viewpoint of sufficiently increasing the conductivity between the facing circuit electrodes. As the inorganic oxide fine particles, fine particles made of an oxide containing at least one element selected from silicon, aluminum, zirconium, titanium, niobium, zinc, tin, cerium, and magnesium can be suitably used. These can be used alone or in combination of two or more.

The insulating fine particles 6 have a hydroxyl group on the surface. A part of this hydroxyl group may be modified to an amino group, a carboxyl group, or an epoxy group with a silane coupling agent or the like. Usually, when the particle diameter of the inorganic oxide fine particles is 500 nm or less, it is difficult to modify, and therefore it is preferable to use the insulating fine particles 6 without modification.

Generally, a hydroxyl group forms a strong bond with a functional group such as a hydroxyl group, a carboxyl group, an alkoxy group, or an alkoxycarbonyl group by a covalent bond or a hydrogen bond by dehydration condensation. Since the conductive particles 8 have these functional groups on their surfaces, the conductive particles 8 and the insulating particles 6 have a strong bonding force. Furthermore, the surface potential of the insulating fine particles 6 is preferably a negative potential. When the surface potential of the insulating fine particles 6 is a negative potential, the insulating fine particles 6 are easily bonded to the conductive particles 8 having a functional group.

The insulating fine particles 6 are particularly preferably water-dispersed colloidal silica (SiO ₂ ) having a controlled particle size among the inorganic oxide fine particles. If it is water-dispersed colloidal silica (SiO ₂ ), the insulation between adjacent circuit electrodes can be further improved. Since the water-dispersed colloidal silica has a hydroxyl group on the surface, it has advantages such as excellent bonding strength with the conductive particles 8, easy alignment of particle diameters, and low cost. In order to improve insulation reliability, it is desirable that the concentration of alkali metal ions and alkaline earth metal ions in the dispersion solution is 100 ppm or less. Further, inorganic oxide fine particles produced by a hydrolysis reaction of metal alkoxide, so-called sol-gel method, are preferable.

The average particle diameter of the insulating fine particles 6 is preferably 20 to 500 nm. When the particle size is 20 nm or more, the insulating fine particles 6 covering the conductive particles 8 function well as an insulator as compared with the case where the particle size is less than 20 nm, and short-circuits between circuit electrodes adjacent to each other on the same substrate. Can be further suppressed. On the other hand, when the particle size is 500 nm or less, the conductivity between the facing circuit electrodes tends to be improved as compared with the case where the particle diameter exceeds 500 nm. The particle size can be measured by the specific surface area conversion method by the BET method or the X-ray small angle scattering method.

It is preferable that the insulating fine particles 6 are harder than the conductive particles 8. By making the insulating fine particles 6 harder than the conductive particles 8, the insulating coated conductive particles 10 are not easily deformed when an anisotropic conductive adhesive film is produced. It can be confirmed that the insulating fine particles 6 are harder than the conductive particles 8 by measuring the hardness of the particles. Hardness can be measured by Mohs hardness (gold: 2.5, nickel: 3.8, silica: 7.0).

It is preferable that the insulating fine particles 6 cover the surface of the conductive particles 8 with one layer. When covered with one layer, it is easier to control the amount of the insulating fine particles 6 laminated than when a plurality of insulating fine particles 6 are laminated on the surface of the conductive particles 8.

The ratio of the surface where the conductive particles 8 are covered with the insulating fine particles 6, that is, the coverage of the surface of the conductive particles 8 with the insulating fine particles 6 is preferably 30 to 50%. Here, 100% refers to the case where the surface of the conductive particles 8 is a flat surface and the insulating fine particles 6 are finely packed in the flat surface. Moreover, it is preferable that the CV value of the said coverage is 20% or less. The CV value is a value obtained by dividing the standard deviation of the coverage by the average value, and indicates variation. When the said coverage is high, there exists a tendency for the insulation between the circuit electrodes which adjoin on the same board | substrate to become high, and for the electrical conductivity between the circuit electrodes which oppose to fall. When the said coverage is low, the said electroconductivity becomes high and there exists a tendency for the said insulation to fall.

The insulating coated conductive particles 10 according to the present embodiment can be obtained by coating the insulating fine particles 6 after adsorbing the polymer electrolyte on the surface of the conductive particles 8.

In general, such a method is called a layer-by-layer assembly. The alternate lamination method is described in G.H. This is a method for forming an organic thin film published in 1992 by Decher et al. (Thin Solid Films, 210/211, 1992, p. 831). In this method, the substrate is alternately immersed in an aqueous solution of a polymer electrolyte (polycation) having a positive charge and an aqueous solution of a polymer electrolyte (polyanion) having a negative charge, and is adsorbed onto the substrate by electrostatic attraction. A combination of a polycation and a polyanion can be laminated to obtain a composite film (alternate laminated film).

In the alternate lamination method, the film is grown by electrostatic attraction between the material charge formed on the substrate and the material having the opposite charge in the solution due to electrostatic attraction. When charge neutralization occurs, no further adsorption occurs. Therefore, when reaching a certain saturation point, the film thickness does not increase any more.

Lvov et al. Also applied an alternate lamination method to fine particles and reported a method of laminating a polymer electrolyte having a charge opposite to the surface charge of the fine particles, using silica, titania, and ceria fine particle dispersions. (Langmuir, Vol. 13, 1997, p. 6195-6203). By using this method, silica fine particles having a negative surface charge and polydiallyldimethylammonium chloride (PDDA) or polyethyleneimine (PEI), which are polycations having the opposite charge, are alternately laminated to form silica. It is possible to form a fine particle laminated thin film in which fine particles and a polymer electrolyte are alternately laminated.

As a method for producing the insulating coated conductive particles 10, the conductive particles 8 are contained in a solution containing a compound having a mercapto group, sulfide group or disulfide group and at least one functional group selected from a hydroxyl group, a carboxyl group, an alkoxy group and an alkoxycarbonyl group. A first step of contacting or bonding the compound to the surface of the conductive particles 8 and contacting the conductive particles 8 with a solution containing a polymer electrolyte to adhere the polymer electrolyte to the surface of the conductive particles 8 Insulating to cover at least a part of the surface of the conductive particles 8 and the conductive particles 8 by bringing the conductive particles 8 into contact with the second step and the dispersion containing the insulating fine particles 6 which are inorganic oxide fine particles having hydroxyl groups on the surface. And a third step of obtaining the insulating coated conductive particles 10 having the conductive fine particles 6 in this order.

The solution containing the polymer electrolyte used in the above production method is obtained by dissolving the polymer electrolyte in water or a mixed solvent of water and a water-soluble organic solvent. Examples of water-soluble organic solvents that can be used include methanol, ethanol, propanol, acetone, dimethylformamide, acetonitrile, and the like. A polymer electrolyte that is soluble in water or a mixed solvent of water and a water-soluble organic solvent, is ionized in an aqueous solution, and has a functional group having a charge in the main chain or side chain. Of these, polycations are preferred. Polycations having a positively charged functional group such as polyamines such as polyethyleneimine (PEI), polyallylamine hydrochloride (PAH), polydiallyldimethylammonium chloride (PDDA), polyvinylpyridine (PVP), polylysine, polyacrylamide, or a copolymer containing at least one of these polycations can be used. The adsorption of these polymer electrolytes on the surface of the conductive particles 8 can be confirmed by an analysis technique such as X-ray electron spectroscopy or time-of-flight secondary ion mass spectrometry.

Among the polycations described above, polyethyleneimine has a high charge density and can be preferably used because of its strong binding force with the conductive particles 8. The weight average molecular weight of the polymer electrolyte cannot be determined unconditionally because it depends on the type of polymer electrolyte to be used, but from the viewpoint of improving the water solubility and the amount of adsorption to the conductive particles 8, and the ease of handling, In general, about 500 to 200,000 is preferable.

As a method of bringing the conductive particles 8 into contact with a solution containing the polymer electrolyte, for example, a method of immersing the conductive particles 8 in a polymer electrolyte solution in which the polymer electrolyte is dissolved in water or a mixed solvent of water and a water-soluble organic solvent. Is mentioned. In this case, the concentration of the polymer electrolyte in the polymer electrolyte solution is usually 0.01 to 10 mass from the viewpoints of improving the water solubility and the amount of adsorption to the functional group-containing conductive particles and the ease of handling. % Is preferred. The pH of the polymer electrolyte solution is not particularly limited.

As the water-soluble organic solvent, for example, methanol, ethanol, propanol, acetone, dimethylformamide, acetonitrile and the like can be used. In order to avoid electromigration and corrosion as a solution containing a polymer electrolyte, alkali metal (Li, Na, K, Rb, Cs) ions, alkaline earth metal (Ca, Sr, Ba, Ra) ions, and What does not contain halide ions (fluorine ions, chloride ions, bromine ions, iodine ions) is preferred.

By adjusting the type, molecular weight, and concentration of the polymer electrolyte adsorbed on the surface of the conductive particles 8, the coverage of the surface of the conductive particles 8 with the insulating fine particles 6 can be controlled. Specifically, when a polymer electrolyte having a high charge density such as polyethyleneimine is used, the coverage by the insulating fine particles 6 tends to be high, and a polymer electrolyte having a low charge density such as polydiallyldimethylammonium chloride is used. When it is, there exists a tendency for the said coverage to become low. Moreover, when the molecular weight of the polymer electrolyte is large, the coverage tends to be high, and when the molecular weight of the polymer electrolyte is small, the coverage tends to be low. Furthermore, when the polymer electrolyte is used at a high concentration, the coverage tends to be high, and when the polymer electrolyte is used at a low concentration, the coverage tends to be low.

In the method of manufacturing the insulating coated conductive particles 10 described above, after the step of bringing the polymer electrolyte into contact with the surface of the conductive particles 8 in the second step, the excess polymer electrolyte that is not adsorbed on the surfaces of the conductive particles 8 is washed away. The process and the process of washing away the excess insulating fine particles 6 not covering the conductive particles 8 after the step of bringing the insulating fine particles 6 into contact with the surfaces of the conductive particles 8 in the third step may be further provided.

As the cleaning solvent used in the step of washing away the polymer electrolyte and the insulating fine particles 6 described above, water, alcohol, acetone or the like can be used. Note that the polymer electrolyte adsorbed on the surface of the conductive particles 8 and / or the insulating fine particles 6 bonded to the surface of the conductive particles 8 directly or via the polymer electrolyte are the above-mentioned surplus polymer electrolyte and surplus. In the step of washing away the insulative fine particles 6, it is not usually peeled off.

By performing the above-described step of washing away the excess polymer electrolyte and the step of washing away the insulating fine particles 6, the insulating fine particles 6 are brought into the polymer electrolyte solution, and the polymer electrolyte is dispersed in the insulating fine particles 6. Can be prevented. If cations and anions are mixed in the dispersion of insulating fine particles and the polymer electrolyte solution due to carry-in, aggregation and precipitation of the polymer electrolyte and the insulating fine particles may occur.

The bonding strength between the insulating fine particles 6 and the conductive particles 8 can be further enhanced by heating and drying the insulating coated conductive particles 10 produced as described above. This is because a chemical bond between a functional group such as a carboxyl group on the surface of the conductive particles 8 and a hydroxyl group on the surface of the insulating fine particles 6 is newly formed. The insulating coated conductive particles 10 are preferably dried by heating in the range of 60 to 200 ° C. and 10 to 180 minutes. When the temperature is higher than 60 ° C., or when the heating time is 10 minutes or longer, compared with the case where the temperature is lower than 60 ° C. or the heating time is shorter than 10 minutes, the surface of the conductive particles 8 is insulated. There is a tendency that the fine particles 6 are difficult to peel off. On the other hand, when the temperature is lower than 200 ° C. or when the heating time is shorter than 180 minutes, the conductive particles 8 are less likely to be deformed than when the temperature is higher than 200 ° C. or when the heating time is longer than 180 minutes. There is a tendency.

In the insulating coated conductive particles 10, the coating amount of the insulating fine particles is preferably 0.2 to 2.6 parts by mass, and 0.8 to 2.0 parts by mass with respect to 100 parts by mass of the conductive particles. Is more preferable. If the coating ratio of the insulating fine particles to 100 parts by mass of the conductive particles is less than 0.2 parts by mass, it is difficult to obtain good insulation, and if it exceeds 2.6 parts by mass, the electrical resistance value of the circuit connection part tends to increase. Tend to be. Further, the coating ratio of the insulating fine particles is preferably 0.7 to 8.6 parts by mass, more preferably 1.0 to 8.0 parts by mass with respect to 100 parts by mass of the base particles.

The ratio of the insulating coated conductive particles 10 in the circuit connection material is 0.1 to 30 based on the entire circuit connection material from the viewpoint of improving the insulation between the adjacent circuit electrodes and the conductivity between the opposing circuit electrodes. % By volume is preferred, 0.5 to 25% by volume is more preferred, and 1 to 10% by volume is still more preferred.

(Adhesive composition)
Next, the adhesive composition according to this embodiment will be described. The resin layer 12 preferably contains an epoxy resin and a latent curing agent. That is, the circuit connection material 50 can contain an adhesive composition containing an epoxy resin and a latent curing agent, and the insulating coated conductive particles 10. When the circuit connection material 50 is heated, a crosslinked structure is formed in the resin layer 12 by curing of the epoxy resin, and a cured product of the circuit connection material 50 is formed. In this case, the circuit connection material 50 functions as an epoxy curable adhesive.

Typical epoxy resins include bisphenol type epoxy resins that are glycidyl ethers of bisphenols such as bisphenol A, F, and AD, and epoxy novolac resins derived from phenol novolac or cresol novolac. Other examples include naphthalene type epoxy resins having a naphthalene skeleton, glycidyl amine type epoxy resins, glycidyl ether type epoxy resins, alicyclic epoxy resins, and heterocyclic epoxy resins. These are used individually or in mixture of 2 or more types.

Among the above epoxy resins, bisphenol type epoxy resins are preferred because they are widely available in grades with different molecular weights, and adhesiveness and reactivity can be arbitrarily set. Among bisphenol type epoxy resins, bisphenol F type epoxy resins are particularly preferable. The viscosity of the bisphenol F type epoxy resin is low, and the fluidity of the circuit connecting material can be easily set in a wide range by using it in combination with the phenoxy resin. Further, the bisphenol F type epoxy resin has an advantage that it is easy to impart good adhesiveness to the circuit connecting material.

It is preferable to use an epoxy resin having an impurity ion (Na ⁺ , Cl ⁻ etc.) concentration or hydrolyzable chlorine of 300 ppm or less to prevent electron migration.

Any latent curing agent may be used as long as it can cure the epoxy resin. The latent curing agent may be a compound that reacts with the epoxy resin and is incorporated into the crosslinked structure, or may be a catalytic curing agent that accelerates the curing reaction of the epoxy resin. Both can be used in combination.

Examples of the catalytic curing agent include an anionic polymerization latent curing agent that promotes anionic polymerization of an epoxy resin and a cationic polymerization latent curing agent that promotes cationic polymerization of an epoxy resin.

Examples of the anionic polymerization type latent curing agent include imidazole series, hydrazide series, trifluoroboron-amine complex, amine imide, polyamine salt, dicyandiamide, and modified products thereof. The imidazole-based anionic polymerization latent curing agent is formed, for example, by adding imidazole or a derivative thereof to an epoxy resin.

As the cationic polymerization type latent curing agent, for example, a photosensitive onium salt (mainly used is an aromatic diazonium salt, an aromatic sulfonium salt, or the like) that cures an epoxy resin by irradiation with energy rays. In addition to irradiation with energy rays, there is an aliphatic sulfonium salt that is activated by heating to cure the epoxy resin. This type of curing agent is preferred because it has the feature of fast curability.

When these latent curing agents are coated with a polymer material such as polyurethane or polyester, a metal thin film such as nickel or copper, and an inorganic material such as calcium silicate, the pot life can be extended. Therefore, it is preferable.

The blending amount of the latent curing agent is preferably 30 to 60 parts by mass and more preferably 40 to 55 parts by mass with respect to 100 parts by mass of the epoxy resin. When the blending amount of the latent curing agent is less than 30 parts by mass, the tightening force on the adherend due to curing shrinkage of the circuit connecting material is reduced. As a result, the contact between the insulating coating particle 10 and the circuit electrode is not maintained, and the connection resistance after the reliability test tends to increase. On the other hand, if the blending amount of the latent curing agent exceeds 60 parts by mass, the tightening force becomes too strong, so that the internal stress in the cured product of the circuit connection material tends to increase, and the adhesive strength tends to decrease.

When the circuit connecting material is an epoxy resin adhesive, it is preferable to contain a film forming material. The film-forming material, when the liquid is solidified and the constituent composition is made into a film shape, facilitates the handling of the film and imparts mechanical properties that do not easily tear, crack, or stick. The film can be handled in a normal state (normal temperature and pressure).

Examples of the film forming material include phenoxy resin, polyvinyl formal resin, polystyrene resin, polyvinyl butyral resin, polyester resin, polyamide resin, xylene resin, and polyurethane resin. Among the film forming materials, a phenoxy resin is preferable because of excellent adhesiveness, compatibility, heat resistance, and mechanical strength.

The phenoxy resin is a resin obtained by reacting a bifunctional phenol and epihalohydrin until they are polymerized, or by polyaddition of a bifunctional epoxy resin and a bifunctional phenol. For example, the phenoxy resin contains 1 mol of a bifunctional phenol and 0.985 to 1.015 mol of epihalohydrin in the presence of a catalyst such as an alkali metal hydroxide at a temperature of 40 to 120 ° C. in a non-reactive solvent. It can be obtained by reacting.

Further, as the phenoxy resin, from the viewpoint of the mechanical properties and thermal properties of the resin, the blending equivalent ratio of the bifunctional epoxy resin and the bifunctional phenols is particularly preferably epoxy group / phenol hydroxyl group = 1 / 0.9. In the presence of a catalyst such as an alkali metal compound, an organophosphorus compound, or a cyclic amine compound, an amide, ether, ketone, lactone, alcohol, or the like having a boiling point of 120 ° C. or higher. A product obtained by polyaddition reaction by heating to 50 to 200 ° C. in an organic solvent under a reaction solid content of 50% by mass or less is preferable.

Bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, and bisphenol S type epoxy resin can be used as the bifunctional epoxy resin. Bifunctional phenols have two phenolic hydroxyl groups, and examples thereof include bisphenol compounds such as hydroquinones, bisphenol A, bisphenol F, bisphenol AD, and bisphenol S.

The phenoxy resin may be modified with a radical polymerizable functional group. A phenoxy resin can be used individually by 1 type or in mixture of 2 or more types.

The resin layer 12 may contain a curing agent that generates free radicals and a radical polymerizable substance, instead of the epoxy resin and the latent curing agent. In other words, the circuit connection material 50 preferably contains an adhesive composition containing a curing agent that generates free radicals, a radical polymerizable substance, and the insulating coated conductive particles 10. When the circuit connection material 50 is heated, a crosslinked structure is formed in the resin layer 12 by polymerization of the radical polymerizable substance, and a cured product of the circuit connection material 50 is formed. In this case, the circuit connection material 50 functions as a radical curable adhesive.

The curing agent that generates free radicals used in the circuit connection material 50 is one that decomposes by heating of a peroxide compound, an azo compound, or the like to generate free radicals. The target connection temperature, connection time, pot life It is selected as appropriate. The blending amount is preferably 0.05 to 10% by mass, based on the total mass of the circuit connection material 50, and 0.1 to 5% by mass (0.05 to 10% with 100% by mass as the total mass of the circuit connection material 50). Part by mass, preferably 0.1 to 5 parts by mass). Specifically, the curing agent that generates free radicals can be selected from diacyl peroxide, peroxydicarbonate, peroxyester, peroxyketal, dialkyl peroxide, hydroperoxide, and the like. Further, in order to suppress corrosion of the connection terminals of the circuit member, it is preferably selected from peroxyesters, dialkyl peroxides, and hydroperoxides, and more preferably selected from peroxyesters that provide high reactivity. .

Examples of the diacyl peroxide include 2,4-dichlorobenzoyl peroxide, 3,5,5, -trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinic peroxide, and benzoyl. Examples include peroxytoluene and benzoyl peroxide.

Examples of peroxydicarbonates include di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis (4-tert-butylcyclohexyl) peroxydicarbonate, and di-2-ethoxymethoxyperoxydicarbonate. Di (2-ethylhexylperoxy) dicarbonate, dimethoxybutylperoxydicarbonate, and di (3-methyl-3-methoxybutylperoxy) dicarbonate.

Examples of peroxyesters include 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxynodecanoate, and t-hexylperoxyneodecane. Noate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di (2-ethylhexanoyl) Peroxy) hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanate, t-hexylperoxy-2-ethylhexanate, t-butylperoxy-2-ethylhexanate, t- Butyl peroxyisobutyrate, 1,1-bis (t-butylperoxy) cyclohexane, t-hexyl peroxy Isopropyl monocarbonate, t-butylperoxy-3,5,5-trimethylhexanonate, t-butylperoxylaurate, 2,5-dimethyl-2,5-di (m-toluoylperoxy) hexane, Examples thereof include t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, and t-butyl peroxyacetate.

Examples of peroxyketals include 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis. (T-Butylperoxy) -3,3,5-trimethylcyclohexane, 1,1- (t-butylperoxy) cyclododecane, 2,2-bis- (t-butylperoxy) decane.

Examples of dialkyl peroxides include α, α'-bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, Examples thereof include t-butyl cumyl peroxide.

Examples of hydroperoxides include diisopropylbenzene hydroperoxide and cumene hydroperoxide.

These curing agents that generate free radicals can be used alone or in combination, and may be used in combination with a decomposition accelerator, an inhibitor, and the like. In addition, it is preferable to use these hardeners coated with a polyurethane-based or polyester-based polymer substance to form microcapsules because the pot life is extended.

The radical polymerizable substance used for the circuit connecting material 50 is a substance having a functional group that is polymerized by radicals, and examples thereof include acrylates, methacrylates, maleimide compounds, citraconic imide resins, and nadiimide resins. The blending amount of the radical polymerizable substance is preferably 20 to 50 parts by mass, and more preferably 30 to 40 parts by mass, where the total mass of the circuit connecting material 50 is 100 parts by mass. The radical polymerizable substance can be used in any state of a monomer and an oligomer, and a monomer and an oligomer can be used in combination.

Examples of the acrylate (including the corresponding methacrylate, hereinafter the same) include, for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, 2-hydroxy-1,3-diaacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane, 2,2-bis [4- (acryloxypolyethoxy) phenyl] propane, dicyclo Examples include pentenyl acrylate, tricyclodecanyl acrylate, tris (acryloyloxyethyl) isocyanurate, and urethane acrylate. These may be used alone or in combination of two or more, and a polymerization inhibitor such as hydroquinone or methyl ether hydroquinone may be used as necessary. Moreover, when it has a dicyclopentenyl group and / or a tricyclodecanyl group and / or a triazine ring, since heat resistance improves, it is preferable.

Examples of the maleimide compound include those containing at least two maleimide groups in the molecule, such as 1-methyl-2,4-bismaleimidebenzene, N, N′-m-phenylenebismaleimide, N, N ′. -P-phenylene bismaleimide, N, N'-m-toluylene bismaleimide, N, N'-4,4-biphenylene bismaleimide, N, N'-4,4- (3,3'-dimethylbiphenylene) Bismaleimide, N, N′-4,4- (3,3′-dimethyldiphenylmethane) bismaleimide, N, N′-4,4- (3,3′-diethyldiphenylmethane) bismaleimide, N, N′- 4,4-diphenylmethane bismaleimide, N, N′-4,4-diphenylpropane bismaleimide, N, N′-3,3′-diphenylsulfone bismale N, N′-4,4-diphenyl ether bismaleimide, 2,2-bis (4- (4-maleimidophenoxy) phenyl) propane, 2,2-bis (3-s-butyl-4,8- ( 4-maleimidophenoxy) phenyl) propane, 1,1-bis (4- (4-maleimidophenoxy) phenyl) decane, 4,4′-cyclohexylidene-bis (1- (4-maleimidophenoxy) -2-cyclohexyl Examples thereof include benzene and 2,2-bis (4- (4-maleimidophenoxy) phenyl) hexafluoropropane, which can be used alone or in combination of two or more.

The citraconic imide resin is obtained by polymerizing a citraconic imide compound having at least one citraconic imide group in the molecule. Examples of the citraconic imide compound include phenyl citraconic imide, 1-methyl-2,4 -Biscitraconimide benzene, N, N'-m-phenylene biscitraconimide, N, N'-p-phenylene biscitraconimide, N, N'-4,4-biphenylenebiscitraconimide, N, N'-4 , 4- (3,3-Dimethylbiphenylene) biscitraconimide, N, N′-4,4- (3,3-dimethyldiphenylmethane) biscitraconimide, N, N′-4,4- (3,3- Diethyldiphenylmethane) biscitraconimide, N, N′-4,4-diphenylmethanebiscitraconimide, N'-4,4-diphenylpropane biscitraconimide, N, N'-4,4-diphenyl ether biscitraconimide, N, N'-4,4-diphenylsulfone biscitraconimide, 2,2-bis (4 -(4-citraconimidophenoxy) phenyl) propane, 2,2-bis (3-s-butyl-3,4- (4-citraconimidophenoxy) phenyl) propane, 1,1-bis (4- (4- Citraconimidophenoxy) phenyl) decane, 4,4′-cyclohexylidene-bis (1- (4-citraconimidophenoxy) phenoxy) -2-cyclohexylbenzene, 2,2-bis (4- (4-citraconimidophenoxy) ) Phenyl) hexafluoropropane. These can be used alone or in combination of two or more.

The nadiimide resin is obtained by polymerizing a nadiimide compound having at least one nadiimide group in the molecule. Examples of the nadiimide compound include phenyl nadiimide, 1-methyl-2,4-bisnadiimidebenzene, N, N′-m-phenylenebisnadiimide, N, N′-p-phenylenebisnadiimide, N, N′-4,4-biphenylenebisnadiimide, N, N′-4,4- (3,3-dimethyl Biphenylene) bisnadiimide, N, N′-4,4- (3,3-dimethyldiphenylmethane) bisnadiimide, N, N′-4,4- (3,3-diethyldiphenylmethane) bisnadiimide, N, N′-4,4 -Diphenylmethane bisnadiimide, N, N'-4,4-diphenylpropane bisnadiimide, N, N'-4,4-diphenyl -Terbisnadiimide, N, N'-4,4-diphenylsulfone bisnadiimide, 2,2-bis (4- (4-nadiimidophenoxy) phenyl) propane, 2,2-bis (3-s-butyl- 3,4- (4-Nadiimidophenoxy) phenyl) propane, 1,1-bis (4- (4-nadiimidophenoxy) phenyl) decane, 4,4′-cyclohexylidene-bis (1- (4- Nadiimidophenoxy) phenoxy) -2-cyclohexylbenzene, 2,2-bis (4- (4-nadiimidophenoxy) phenyl) hexafluoropropane. These can be used alone or in combination of two or more.

The circuit connection material 50 (resin layer 12) may contain other components in addition to the curing agent that generates free radicals and the radical polymerizable substance. For example, a thermoplastic resin and a thermosetting resin can be contained.

As the above thermoplastic resin, polyethylene resin, polyimide resin, polyvinyl chloride resin, polyphenylene oxide resin, polyvinyl butyral resin, polyvinyl formal resin, polyamide resin, polyester resin, phenoxy resin, polystyrene resin, xylene resin, polyurethane resin, etc. are used. it can.

Further, as the thermoplastic resin, a hydroxyl group-containing resin having a Tg (glass transition temperature) of 40 ° C. or higher and a molecular weight of 10,000 or more can be preferably used. For example, a phenoxy resin can be preferably used. The phenoxy resin can be obtained by reacting a bifunctional phenol with epihalohydrin until it has a high molecular weight or by polyaddition reaction of a bifunctional epoxy resin with a bifunctional phenol.

Examples of thermosetting resins include urea resins, melamine resins, phenol resins, xylene resins, epoxy resins, polyisocyanate resins, and the like.

When the above thermoplastic resin is contained, it is preferable because it is easy to handle and is excellent in stress relaxation during curing. Further, the thermoplastic resin and the thermosetting resin are more preferable when having a functional group such as a hydroxyl group because the adhesiveness is improved, and may be modified with an epoxy group-containing elastomer or a radical polymerizable functional group. Those modified with a radically polymerizable functional group are preferred because the heat resistance is improved.

The weight average molecular weight of the thermoplastic resin is preferably 10,000 or more from the viewpoint of film forming property, but if it is 1000000 or more, the mixing property tends to be poor. In addition, the weight average molecular weight prescribed | regulated by this application means what was measured using the analytical curve by a standard polystyrene by the gel permeation chromatography method (GPC) according to the following conditions.

<GPC conditions>
Equipment used: Hitachi L-6000 (manufactured by Hitachi, Ltd.)
Column: Gel pack GL-R420 + Gel pack GL-R430 + Gel pack GL-R440 (3 in total) (manufactured by Hitachi Chemical Co., Ltd.)
Eluent: Tetrahydrofuran Measurement temperature: 40 ° C
Flow rate: 1.75 mL / min Detector: L-3300RI (manufactured by Hitachi, Ltd.)

Furthermore, the circuit connection material 50 (resin layer 12) may contain a filler, a softening material, an accelerator, an anti-aging agent, a colorant, a flame retardant, a thixotropic agent, a coupling agent, isocyanates, and the like. it can. The inclusion of a filler is preferable because it improves connection reliability and the like. If the maximum diameter of the filler is less than the particle diameter of the insulating coating particles 10, it can be used, and the blending amount is preferably in the range of 5 to 60% by volume. If it exceeds 60% by volume, the effect of improving reliability is saturated. As a coupling agent, a vinyl group, an acryl group, an amino group, an epoxy group, and an isocyanate group-containing material are preferable from the viewpoint of improving adhesiveness. A polymerization inhibitor such as hydroquinone or methyl ether hydroquinone may be used as necessary.

The circuit connection material 50 has an elastic modulus at 40 ° C. of 0.5 to 1.0 GPa after curing, and more preferably 0.6 to 0.9 GPa. If the elastic modulus after curing of the circuit connection material is less than 0.5 GPa, the connection resistance between the opposing electrodes tends to increase, and if it exceeds 1.0 GPa, it tends to be difficult to obtain a sufficient adhesive force. .

The elastic modulus after curing of the circuit connecting material 50 is a thermosetting resin component such as an epoxy resin or a radical polymerizable substance contained in the adhesive composition, or a thermoplastic resin such as an elastomer (for example, acrylic rubber or urethane rubber). It can adjust to a predetermined range by adjusting the compounding quantity of a component and / or a polyfunctional component, respectively.

The elastic modulus of the circuit connection material 50 after curing can be measured using, for example, a dynamic viscoelasticity measuring device (trade name “Solid analyzer RSA2” manufactured by Rheometric Scientific).

The circuit connection material according to the present embodiment includes, for example, chip components such as a semiconductor chip, a resistor chip and a capacitor chip, and circuit members having one or more circuit electrodes (connection terminals) such as a printed circuit board. It is preferably used to form a connected connection structure. That is, it contains an adhesive composition and insulating coated conductive particles, has an elastic modulus at 40 ° C. after curing of 0.5 to 1.0 GPa, and the insulating coated conductive particles are composed of substrate particles and the substrate. A conductive particle having a metal plating layer covering at least a part of the surface of the particle, and insulating fine particles covering at least a part of the surface of the conductive particle, and at 20% compression deformation of the particle diameter of the conductive particle A material having a compressive modulus of 800-3500 N / mm ² can be used for circuit connection. The circuit connection material according to the present embodiment is particularly useful in COF mounting having a narrower connection pitch.

FIG. 4 is a cross-sectional view showing an embodiment of a connection structure. The connection structure 100 shown in FIG. 4 includes a first circuit member 20 having a first circuit electrode 23 formed on a first substrate 21 and a main surface 21a of the first substrate 21, a second substrate 31, and A second circuit member 30 having a second circuit electrode 33 formed on the main surface 31a, and disposed so that the second circuit electrode 33 and the first circuit electrode 23 face each other; The connection part 50a interposed between the circuit member 20 and the second circuit member 30 is provided. The first circuit electrode 23 and the second circuit electrode 33 facing each other are electrically connected.

The connection part 50a is a cured product formed by curing the circuit connection material 50, and is composed of a cured product 12a of the adhesive composition and the insulating coated conductive particles 10. The connection portion 50a bonds the first circuit member 20 and the second circuit member 30 so that the first circuit electrode 23 and the second circuit electrode 33 facing each other are electrically connected. . The first circuit electrode 23 and the second circuit electrode 33 facing each other are electrically connected through the insulating coated conductive particles 10.

The first substrate 21 is preferably a resin film containing at least one resin selected from the group consisting of polyester terephthalate, polyethersulfone, epoxy resin, acrylic resin and polyimide resin. The first circuit electrode 23 is formed from a material having conductivity that can function as an electrode (preferably at least one selected from the group consisting of gold, silver, tin, platinum group metals, and indium-tin oxide). Has been.

The second substrate 31 is preferably a glass substrate. The second circuit electrode 32 is preferably formed from a transparent conductive material. Typically, ITO is used as the transparent conductive material.

The circuit member connection structure 100 includes, for example, a first circuit member 20 having a first substrate and a first circuit electrode formed on the main surface thereof, and a second substrate and the main surface thereof. A step of obtaining a laminate by interposing the above-mentioned film-like circuit connecting material 50 between a pair of circuit members including the second circuit member 30 having the formed second circuit electrode; and The circuit connection material 50 is cured by heating and pressurization, so that the first circuit electrode 23 and the second circuit electrode 33 that are disposed between and opposed to each other are electrically connected to each other. And a step of forming a connection portion 50a for bonding a pair of circuit members to each other.

In this method, first, the circuit-connecting material 50 and the first circuit-connecting material 50 formed on the support film are heated and pressed in a state of being bonded to the main surface of the second circuit member 30. The second circuit member 30 is temporarily bonded. And after peeling the support film, the main surface of the first circuit member 20 is bonded to the circuit connection material 50 while aligning the first circuit electrode 23 and the second circuit electrode 33, A laminate can be prepared. In addition, in order to prevent the influence on the connection by the volatile component which generate | occur | produces by the heating in the case of a connection, it is preferable to heat-process a circuit member previously before a connection process.

The connection structure 100 connected in this way has conductivity between the circuit electrode 22 and the circuit electrode 32 facing each other, and insulation between the adjacent circuit electrodes 22 and the circuit electrodes 32 on the same substrate. And excellent.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited thereto.

(1) Preparation of circuit connection material Each component which comprises the circuit connection material in a present Example was prepared as follows.

(1-1) Preparation of Insulating Coated Conductive Particles First, a 0.07 μm thick nickel layer is provided on the surface of crosslinked polystyrene particles having an average particle diameter of 2.9 μm by electroless plating, and 0.03 μm thick gold is further formed on the outer layer. Conductive particles A having an average particle diameter of 3.0 μm provided with layers by electroless plating were prepared. The conductive particles A were adjusted so that the 20% K value was 1100 to 1900 N / mm ² . The load at the time of 20% deformation of the conductive particles A was 0.4 to 0.5 mN. Next, after treating the surface of the conductive particles A with a polyethyleneimine aqueous solution, the silica fine particles are coated so that the insulating fine particles are 1.2 to 1.8 parts by mass with respect to 100 parts by mass of the conductive particles A, thereby insulating the particles. Coated conductive particles A were obtained.

First, an average particle diameter in which a nickel layer having a thickness of 0.07 μm is provided on the surface of crosslinked polystyrene particles having an average particle diameter of 3.9 μm by electroless plating, and a gold layer having a thickness of 0.03 μm is provided on the outer layer by electroless plating. 4.0 μm conductive particles B were prepared. The conductive particles B were adjusted to have a 20% K value of 2300 to 2700 N / mm ² . The load at the time of 20% deformation of the conductive particles B was 0.6 to 0.7 mN. Next, after the surface of the conductive particles B is treated with a polyethyleneimine aqueous solution, 100 parts by mass of the conductive particles B are coated with silica fine particles so that the insulating fine particles are 1.0 to 1.6 parts by mass, Coated conductive particles B were obtained.

First, an average particle diameter in which a nickel layer having a thickness of 0.07 μm is provided on the surface of crosslinked polystyrene particles having an average particle diameter of 2.9 μm by electroless plating, and a gold layer having a thickness of 0.03 μm is provided on the outer layer by electroless plating. A 3.0 μm conductive particle C was prepared. The conductive particles C were adjusted to have a 20% K value of 5200 to 5600 N / mm ² . The load at the time of 20% deformation of the conductive particles C was 1.4 to 1.5 mN. Next, the surface of the conductive particles C is treated with a polyethyleneimine aqueous solution, and then the silica particles are coated so that the insulating fine particles are 1.2 to 1.8 parts by mass with respect to 100 parts by mass of the conductive particles C, thereby insulating the particles. Coated conductive particles C were obtained.

(1-2) Preparation of each component constituting adhesive composition “PKHC”: Bisphenol A type phenoxy resin (Mw 45000, manufactured by Inchem Corporation, trade name)
"UR-8200": Polyester urethane (manufactured by Toyobo)
“HTR-P3-TEA”: Copolymer of butyl acrylate / ethyl acrylate / acrylonitrile / glycidyl methacrylate (mass ratio 40/30/30/3) (Mw 850000, manufactured by Nagase ChemteX, trade name)
"T-6075": Urethane rubber (made by DIC Bayer, trade name)
“HX3941HP”: an anionic polymerization type latent curing agent-containing epoxy resin (containing 35% by mass of an imidazole microcapsule type curing agent, product name, manufactured by Asahi Kasei Chemicals)
"UA5500": Urethane acrylate (trade name, manufactured by Shin-Nakamura Chemical)
“DCP-A”: dicyclopentadiene type diacrylate (product name, manufactured by Toagosei Co., Ltd.)
“M-215”: Isocyanuric acid EO-modified diacrylate (product name)
“Perhexa25O”: 2,5-dimethyl-2,5-di (2-ethylhexanoyl) hexane (trade name, manufactured by NOF Corporation)
“SH6040”: Silane coupling agent (γ-glycidoxypropyltrimethoxysilane, manufactured by Toray Dow Corning Silicone Co., Ltd., trade name)
“P-2M”: 2-methacryloyloxyethyl acid phosphate (trade name, manufactured by Kyoeisha Chemical Co., Ltd.)

Example 1
50 parts by mass of “HX3941HP”, 37.5 parts by mass of a 40% by mass toluene / ethyl acetate (= 50/50) solution of “PKHC” (15 parts by mass in terms of nonvolatile content), and 10 mass of “HTR-P3-TEA” % Toluene / ethyl acetate (= 50/50) solution 350 parts by mass (35 parts by mass in terms of non-volatile content) and “SH6040” 2 parts by mass, and further “insulation coated conductive particles A” 3 parts by mass were added. . This mixed solution was applied onto a PET film with an applicator and dried with hot air at 70 ° C. for 10 minutes to obtain a film-like circuit connecting material having an adhesive layer thickness of 20 μm.

(Example 2)
A circuit connection material was obtained in the same manner as in Example 1 except that 3 parts by mass of “insulating coated conductive particles A” was changed to 3 parts by mass of “insulating coated conductive particles B”.

(Example 3)
42.9 parts by mass of 70% by weight toluene solution of “UA5500” (30 parts by mass in terms of non-volatile content), 10 parts by mass of “DCP-A”, 8 parts by mass of 50% by mass hydrocarbon solvent solution of “Perhexa25O” (non-volatile) 4 parts by mass), 30 parts by mass of “UR-8200” in methyl ethyl ketone / toluene (= 50/50) 100 parts by mass (30 parts by mass in terms of nonvolatile content), 10% by mass of “T-6075” 300 parts by mass of methyl ethyl ketone solution (30 parts by mass in terms of nonvolatile content) and 2 parts by mass of “P-2M” were blended, and 3 parts by mass of “insulating coated conductive particles A” were blended. This mixed solution was applied onto a PET film with an applicator and dried with hot air at 70 ° C. for 10 minutes to obtain a film-like circuit connecting material having an adhesive layer thickness of 20 μm.

(Comparative Example 1)
A circuit connection material was obtained in the same manner as in Example 1 except that 3 parts by mass of “insulating coated conductive particles A” was changed to 3 parts by mass of “insulating coated conductive particles C”.

(Comparative Example 2)
60 parts by mass of “HX3941HP”, 40 parts by mass of toluene / ethyl acetate (= 50/50) solution of “PKHC” (20 parts by mass in terms of nonvolatile content), 10% by mass of toluene of “HTR-P3-TEA” / 200 parts by mass of ethyl acetate (= 50/50) solution (20 parts by mass in terms of nonvolatile content) and 2 parts by mass of “SH6040” were further blended, and 3 parts by weight of “insulating coated conductive particles C” were further blended. This mixed solution was applied onto a PET film with an applicator and dried with hot air at 70 ° C. for 10 minutes to obtain a film-like circuit connecting material having an adhesive layer thickness of 20 μm.

(Comparative Example 3)
A circuit connecting material was obtained in the same manner as in Example 1 except that 3 parts by mass of “insulating coated conductive particle A” was changed to 3 parts by mass of “conductive particle A”.

(Comparative Example 4)
A circuit connecting material was obtained in the same manner as in Example 3 except that 3 parts by mass of “insulating coated conductive particles A” was changed to 3 parts by mass of “insulating coated conductive particles C”.

(Comparative Example 5)
42.9 parts by mass of 70% by weight toluene solution of “UA5500” (30 parts by mass in terms of nonvolatile content), 10 parts by mass of “M-215”, 8 parts by mass of 50% by mass hydrocarbon solvent solution of “Perhexa25O” (nonvolatile 4 parts by mass), UR-8200, 30% by mass methyl ethyl ketone / toluene (= 50/50) solution, 167 parts by mass (50 parts by mass in terms of nonvolatile content), and 10% by mass of “T-6075” 100 parts by mass of methyl ethyl ketone solution (10 parts by mass in terms of nonvolatile content) and 2 parts by mass of “P-2M” were blended, and 3 parts by mass of “insulating coated conductive particles C” were blended. This mixed solution was applied onto a PET film with an applicator and dried with hot air at 70 ° C. for 10 minutes to obtain a film-like circuit connecting material having an adhesive layer thickness of 20 μm.

(Comparative Example 6)
A circuit connecting material was obtained in the same manner as in Example 3 except that 3 parts by mass of “insulating coated conductive particle A” was changed to 3 parts by mass of “conductive particle A”.

The composition of the circuit connection material prepared in the examples is shown in Table 1 in terms of parts by mass (in terms of nonvolatile content), and the composition of the circuit connection material prepared in the comparative example is shown in Table 2 in terms of parts by mass (in terms of nonvolatile content).

(1-3) Measurement of elastic modulus of circuit connecting material The film-like circuit connecting materials prepared in the examples and comparative examples were cured in an oven at 180 ° C. for 1 hour, and the elastic modulus of the obtained cured product was adjusted to be dynamic. The temperature was measured using a dynamic viscoelasticity measuring apparatus (trade name “Solid analyzer RSA2” manufactured by Rheometric Scientific) under the condition of a heating rate of 10 ° C./min. The storage elastic modulus at 40 ° C. was defined as the elastic modulus according to the present invention.

(2) Fabrication of circuit member connection structure (2-1) Connection structure 1
A flexible circuit board (hereinafter referred to as “FPC-COF”) having a copper circuit with a line width of 25 μm, a pitch of 40 μm, and a thickness of 8 μm formed directly on a polyimide having a thickness of 38 μm using the above-described circuit connecting material; A glass substrate with an ITO layer having a thickness of 0.7 mm having a thin layer of indium oxide (ITO) was connected in the following procedure.
1) The circuit connecting material was temporarily connected to the ITO layer of the glass substrate by heating and pressing at 80 ° C. and 1 MPa for 5 seconds, and then the PET film was peeled off.
2) After the FPC-COF circuit electrode and the ITO layer of the glass substrate face each other, the connection structure 1 is heated and pressed under the conditions of 190 ° C., 3 MPa, 10 seconds or 170 ° C., 3 MPa, 10 seconds. Was made. The width between the glass substrate, FPC-COF and the substrate was 2 mm.

(2-2) Connection structure 2
Connection structure 1 except that the glass substrate with an ITO layer is changed to a glass substrate with an ITO comb circuit having a thickness of 0.7 mm having a thin layer of indium oxide (ITO) formed with a line width of 26 μm and a space width of 4 μm. A connection structure 2 was produced in the same manner as in the above.

(3) Evaluation of connection structure of circuit members (3-1) Measurement of connection resistance The resistance value between circuits including the circuit connection part of the manufactured connection structure 1 was measured by a two-terminal method using a digital multimeter. . The connection resistance was measured immediately after the connection and after performing a high temperature and high humidity treatment for 500 hours in a constant temperature and humidity chamber at 85 ° C. and 85% RH. The results are shown in Table 3.

(3-2) Measurement of insulation resistance A voltage of 50 V is applied to the manufactured connector structure 2 for 1 minute, and the insulation resistance after application between adjacent electrodes on the substrate is measured using a two-terminal measurement method. Measured with Further, after the connected body was held in a constant temperature and humidity chamber of 85 ° C./85% RH for 500 hours, it was taken out, and after 30 minutes or more had elapsed, the insulation resistance was measured again.

(3-3) Measurement of Adhesive Force A force necessary for peeling FPC-COF from the produced connection structure 1 was measured as an adhesive force. The measurement was performed using an adhesive force measuring device in accordance with JIS Z-0237, with a 90 degree peeling and a peeling speed of 50 mm / min.

DESCRIPTION OF SYMBOLS 2 ... Base particle, 4 ... Metal plating layer, 6 ... Insulating fine particle, 8 ... Conductive particle, 10 ... Insulation coating conductive particle, 12a ... Hardened | cured material of adhesive composition, 12 ... Resin layer, 20 ... 1st Circuit member, 21 ... first substrate, 21a ... first substrate surface, 22 ... first circuit electrode, 30 ... second circuit member, 31 ... second substrate, 31a ... second substrate surface, 32 2nd circuit electrode, 50a ... connection part, 50 ... circuit connection material, 100 ... connection structure.

Claims

A circuit connection material containing an adhesive composition and insulating coated conductive particles,
The elastic modulus at 40 ° C. after curing is 0.5 to 1.0 GPa,
The insulating coated conductive particles comprise conductive particles having base particles and a metal plating layer covering at least a part of the surface of the base particles, and insulating fine particles covering at least a part of the surface of the conductive particles. A circuit connecting material having a compressive elastic modulus at a compressive deformation of 20% of the particle diameter of the conductive particles of 800 to 3500 N / mm 2 .
The circuit connection material according to claim 1, wherein an average particle diameter of the conductive particles is 5.0 μm or less.
A first circuit member having a first substrate and a first circuit electrode formed on a main surface of the first substrate;
A second substrate and a second circuit electrode formed on the main surface of the second substrate, the second circuit electrode and the first circuit electrode being arranged to face each other, and the second circuit A second circuit member having an electrode electrically connected to the first circuit electrode;
A connecting portion interposed between the first circuit member and the second circuit member;
With
A connection structure, wherein the connection part is a cured product of the circuit connection material according to claim 1.
Containing an adhesive composition and insulating coated conductive particles;
The elastic modulus at 40 ° C. after curing is 0.5 to 1.0 GPa,
The insulating coated conductive particles comprise conductive particles having base particles and a metal plating layer covering at least a part of the surface of the base particles, and insulating fine particles covering at least a part of the surface of the conductive particles. Use of a material having a compressive elastic modulus at a compressive deformation of 20% of the particle diameter of the conductive particles of 800 to 3500 N / mm 2 for circuit connection.
The use according to claim 4, wherein an average particle diameter of the conductive particles is 5.0 µm or less.
A first circuit member having a first circuit electrode and a first circuit electrode formed on the main surface thereof, and a second circuit member having a second circuit electrode and a second circuit electrode formed on the main surface thereof. A step of obtaining a laminate by interposing the circuit connection material according to claim 1 between a pair of circuit members including the circuit member;
The laminated body is heated and pressurized to cure the circuit connection material, so that the first circuit electrode and the second circuit electrode that are disposed opposite to each other and interposed between the pair of circuit members are electrically connected. Forming a connection part for bonding the pair of circuit members so as to be connected to each other.