TWI620206B - Substrate particles, conductive particles, conductive materials, and connection structures - Google Patents

Abstract

The present invention provides a substrate particle which can reduce the connection resistance and suppress the occurrence of cracks in the electrode when the electrodes are electrically connected by using conductive particles having a conductive layer formed on the surface thereof.

The substrate particles 11 of the present invention are used to form the conductive layer 2 on the surface to obtain the conductive particles 1 having the conductive layer 2. The substrate particles 11 include cores 12 and core-shell particles of the shell 13 disposed on the surface of the core 12 . The compression recovery ratio of the substrate particles 11 is 50% or more. When the substrate particles 11 were compressed by 10%, the compression elastic modulus was 3000 N/mm ² or more and less than 6000 N/mm ² . The ratio of the load value when the substrate particles 1 were compressed by 30% to the load value at the time of compression of 10% was 3 or less.

Description

Substrate particles, conductive particles, conductive materials, and connection structures

The present invention relates to a substrate particle for forming a conductive layer on a surface to obtain conductive particles having the conductive layer. Further, the present invention relates to a conductive particle, a conductive material, and a bonded structure using the above substrate particles.

Anisotropic conductive materials such as an anisotropic conductive paste and an anisotropic conductive film are widely known. In the anisotropic conductive material described above, conductive particles are dispersed in the binder resin.

The anisotropic conductive material is used to electrically connect electrodes of various connection target members such as a flexible printed circuit board (FPC), a glass substrate, a glass epoxy substrate, and a semiconductor wafer to obtain a connection structure. Further, as the conductive particles, conductive particles having a substrate particle and a conductive layer disposed on the surface of the substrate particle may be used.

An example of the substrate particles used for the conductive particles is disclosed in Patent Document 1 below, in which the shell is an inorganic compound (A), the core is an organic polymer (b), and the core is coated with an organic polymer particle. (B) (substrate particles). Further, Patent Document 1 also discloses conductive particles in which the organic polymer particles (B) are coated with a conductive metal (C).

Further, in the following Patent Document 2, an organic inorganic composite particle (substrate obtained by subjecting a polyfunctional decane compound having a polymerizable unsaturated group to hydrolysis and polycondensation in the presence of a surfactant is disclosed. particle). In the patent document 2, the polyfunctional decane compound is a first fluorene compound containing at least one radical polymerizable group selected from the compounds represented by the following formula (X) and derivatives thereof.

In the above formula (X), R1 represents a hydrogen atom or a methyl group, R2 represents a divalent organic group having 1 to 20 carbon atoms which may have a substituent, R3 represents an alkyl group having 1 to 5 carbon atoms or a phenyl group, and R4 represents At least one monovalent group of a group consisting of a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, and a fluorenyl group having 2 to 5 carbon atoms is selected.

Further, Patent Document 3 listed below discloses a core-shell particle coated with a soft polymer layer on the surface of a hard particle. Preferred examples of the hard particles include metal particles such as nickel; inorganic particles such as glass fibers, alumina, and ceria; and hardened benzoquinone. Resin hardened particles. Patent Document 3 describes that a soft polymer layer is provided to increase the contact area and improve reliability.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2006-156068

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2000-204119

[Patent Document 3] Japanese Patent Laid-Open No. 7-140481

In recent years, there has been a tendency that the interval between the electrodes connected by the conductive particles is narrow and the electrode area is small, and conductive particles which can be connected with lower resistance are required. Further, in order to improve the flexibility of the substrate material, a relatively soft resin film substrate is used in addition to the glass substrate, and conductive particles which do not damage the soft substrate and the electrode are required.

If conductive particles coated with a conductive layer on the surface of the soft substrate particles are used, The contact area between the electrode and the conductive particles is increased, and the conductive particles are less likely to damage the electrode. However, when the soft base material particles are simply used, there is a problem that the adhesive resin between the electrode and the conductive particles cannot be sufficiently removed when the electrodes are connected, and the resin is sandwiched between the electrode and the conductive particles. Or the oxide film on the surface of the conductive layer and the electrode cannot be sufficiently penetrated, and as a result, the connection resistance becomes high. This problem also occurs when a core-shell particle in which a core is covered by a shell and a shell is a relatively soft organic shell is used as a substrate particle.

On the other hand, in the case of using conductive particles coated with a conductive layer on the surface of relatively hard substrate particles such as cerium oxide, the removal property of the binder resin or the oxide film of the surface of the conductive layer and the electrode is penetrated. Sex has changed. However, since the conductive particles are not sufficiently deformed, there is a problem in that the contact area between the electrode and the conductive particles is not sufficiently increased, and the connection resistance is not sufficiently lowered. Further, depending on the pressure bonding conditions at the time of connecting the electrodes, the conductive particles may damage the electrodes and may cause cracks in the electrodes.

Further, the conductive particles lacking in recovery (recovery rate) after compression adversely affect the connection reliability. When the connection structure in which the electrodes are connected between the electrodes is stored under high-temperature conditions and high-humidity conditions by using the conductive particles having reduced resilience after compression, there is a problem that connection failure is likely to occur.

An object of the present invention is to provide a substrate particle which can reduce the connection resistance and suppress the occurrence of cracks in the electrode when the electrodes are electrically connected to each other by using conductive particles having a conductive layer formed on the surface thereof. Moreover, an object of the present invention is to provide a conductive particle, a conductive material, and a bonded structure using the above substrate particles.

According to a broader aspect of the present invention, there is provided a substrate particle for forming a conductive layer on a surface thereof to obtain conductive particles having the conductive layer, wherein the substrate particle has a core and is disposed on the substrate The core shell particle of the shell on the surface of the core, and the compression recovery rate is 50% or more, and the compression elastic modulus when compressing 10% compression is 3000 N/mm ² or more and less than 6000 N/mm ² , and the load is 30% when compressed. The ratio of the value to the load value at 10% compression is 3 or less.

In a specific aspect of the substrate particles of the present invention, the core is an organic core, and the shell is an inorganic shell.

In a specific aspect of the substrate particles of the present invention, the thickness of the shell is 100 nm or more and 5 μm or less.

The compression elastic modulus when the substrate particles are compressed by 30% is preferably 3,000 N/mm ² or less. The load value when the substrate particles are compressed by 40% is preferably 6 or less with respect to the load value when the substrate particles are compressed by 10%. The fracture strain of the substrate particles is preferably 10% or more and 30% or less.

According to a broader aspect of the present invention, there is provided a conductive particle comprising the above-described substrate particles and a conductive layer disposed on a surface of the substrate particle.

In one specific aspect of the conductive particles of the present invention, the conductive particles further include an insulating material disposed on the outer surface of the conductive layer.

In a specific aspect of the conductive particles of the present invention, the conductive particles have protrusions on the outer surface of the conductive layer.

According to a broader aspect of the present invention, there is provided a conductive material comprising conductive particles and a binder resin, wherein the conductive particles comprise the substrate particles and a conductive layer disposed on a surface of the substrate particles .

According to a broader aspect of the invention, a connection structure is provided. The first connection target member having the first electrode on the surface, the second connection target member having the second electrode on the surface, and the connection portion connecting the first connection target member and the second connection target member, and The connection portion is formed of conductive particles or a conductive material containing the conductive particles and a binder resin, and the conductive particles include the substrate particles and a conductive layer disposed on a surface of the substrate particles. Further, the first electrode and the second electrode are electrically connected to each other by the conductive particles.

The substrate particle of the present invention has a core and a core-shell particle disposed on a surface of the core, and the substrate particle of the present invention has a compression recovery ratio of 50% or more and a compression of 10%. The compression elastic modulus is 3000 N/mm ² or more and less than 6000 N/mm ² , and the ratio of the load value when compressing 30% to the load value when compressing 10% is 3 or less, so that a conductive layer is formed on the surface. When the conductive particles are electrically connected between the electrodes, the connection resistance can be lowered, and the occurrence of cracks in the electrode can be suppressed.

1‧‧‧Electrical particles

2‧‧‧ Conductive layer

11‧‧‧Substrate particles

12‧‧‧nuclear

13‧‧‧ shell

21‧‧‧Electrical particles

22‧‧‧ Conductive layer

22A‧‧‧1st conductive layer

22B‧‧‧2nd conductive layer

31‧‧‧Electrical particles

31a‧‧‧ Protrusion

32‧‧‧ Conductive layer

32a‧‧‧ Protrusion

33‧‧‧ core material

34‧‧‧Insulating substances

51‧‧‧Connection structure

52‧‧‧1st connection object component

52a‧‧‧1st electrode

53‧‧‧2nd connection object component

53a‧‧‧2nd electrode

54‧‧‧Connecting Department

Fig. 1 is a cross-sectional view showing conductive particles according to a first embodiment of the present invention.

Fig. 2 is a cross-sectional view showing conductive particles according to a second embodiment of the present invention.

Fig. 3 is a cross-sectional view showing conductive particles according to a third embodiment of the present invention.

Fig. 4 is a front cross-sectional view schematically showing a connection structure using conductive particles according to the first embodiment of the present invention.

The details of the present invention are described below.

(substrate particles)

The substrate particles of the present invention are used to form a conductive layer on a surface to obtain conductive particles having the conductive layer. In other words, the substrate particles of the present invention are substrate particles for conductive particles. The substrate particle of the present invention has a core and a shell disposed on the surface of the core. The substrate particles of the present invention are core-shell particles.

The compression recovery ratio of the substrate particles of the present invention is 50% or more. The compression elastic modulus (10% K value) when the substrate particles of the present invention were compressed by 10% was 3000 N/mm ² or more and less than 6000 N/mm ² . The ratio of the load value (30% load value) when the substrate particles of the present invention is compressed by 30% to the load value (10% load value) at 10% compression (30% load value / 10% load value) is 3 the following.

The substrate particles of the present invention have a high compression recovery ratio, and the substrate particles have an appropriate hardness at the initial stage of compression. Further, in the case of the substrate particles of the present invention, At the stage of degree of compression, the hardness changes, and the softer properties appear. Therefore, in the load value which is not much different from the load value at the initial deformation time point (10% compression deformation point), the deformation in the middle stage (30% compression deformation point) occurs. As a result, when the electrodes are electrically connected by using the conductive particles in which the conductive layer is formed on the surface of the substrate particles, the binder resin can be sufficiently removed by the hardness which is initially formed, and the conductive layer can be made. Or the oxide film on the surface of the electrode is sufficiently penetrated, and the contact area between the electrode and the conductive particles can be sufficiently increased by the flexibility in the middle stage. Therefore, the connection resistance between the electrodes can be lowered, and the connection reliability between the electrodes can be improved. For example, even when the connection structure in which the conductive particles are electrically connected between the electrodes is placed under high temperature conditions and high humidity conditions for a long period of time, the connection resistance is hard to increase, and connection failure is less likely to occur. Further, damage to the electrode and the substrate caused by the conductive particles can be suppressed by the flexibility in the middle stage. Therefore, by using the substrate particles of the present invention, connection failure caused by the occurrence of cracks in the electrode can be suppressed.

The compression recovery ratio of the substrate particles is 50% or more. The above compression recovery ratio is preferably 52% or more. When the compression recovery ratio is equal to or higher than the lower limit, the interval between the electrodes fluctuates and the conductive particles sufficiently follow and are easily deformed. Therefore, it is difficult to cause connection failure between the electrodes.

The above compression recovery rate can be measured in the following manner.

The substrate particles are dispersed on the sample stage. A load (inversion load value) was applied to the center of the substrate particles using a micro compression tester for one of the dispersed substrate particles until the substrate particles were subjected to 30% compression deformation. Thereafter, the pressure was released until the origin load value (0.40 mN). The load-compression displacement in the above period can be measured, and the compression recovery ratio can be obtained from the following equation. Furthermore, the load speed was set to 0.33 mN/sec. For example, "Fischerscope H-100" manufactured by Fischer Co., Ltd. or the like can be used as the above-described micro compression tester.

Compression recovery rate (%) = [(L1-L2) / L1] × 100

L1: Compressive displacement from the origin load value to the reverse load value when the load is applied

L2: the reversal load value from the time of releasing the load until the pressure displacement of the origin load value

The above 10% K value is 2000 N/mm ² or more and less than 6000 N/mm ² . Preferably above 10% K value of 3200N / mm ² or more, more preferably 2500N / mm ² or more, and preferably 5800N / mm ² or less, more preferably 5500N / mm ² or less. When the above-mentioned 10% K value is at least the above lower limit, the binder resin is effectively removed, and the oxide film on the surface of the conductive layer or the electrode is effectively penetrated, and the connection resistance between the electrodes is effectively lowered. When the above 10% K value is equal to or less than the above upper limit, it becomes more difficult to cause cracks in the electrode. When the above 10% K value is 3500 N/mm ² or more, the connection resistance is effectively lowered.

The ratio of the above 30% load value to the above 10% load value (30% load value/10% load value) is 3.0 or less. The above ratio (30% load value/10% load value) is more preferably 2.9 or less. When the ratio (30% load value / 10% load value) is equal to or less than the above upper limit, the contact area between the electrode and the conductive particles is sufficiently increased, and the connection resistance between the electrodes is effectively lowered, and the connection reliability between the electrodes is obtained. Further higher. The above ratio (30% load value/10% load value) is preferably 1.5 or more.

The compression elastic modulus (30% K value) when the substrate particles are subjected to 30% compression deformation is preferably 3,000 N/mm ² or less, more preferably 2,500 N/mm ² or less. When the value of 30% K is less than or equal to the above upper limit, the contact area between the conductive particles and the electrode is further increased, and further, it is more difficult to cause cracks in the electrode. The above 30% K value is preferably 500 N/mm ² or more. When the above 10% K value is 3000 N/mm ² or less, it becomes more difficult to cause cracks in the electrode. When the above 10% K value is 2500 N/mm ² or less, it becomes quite difficult to cause cracks in the electrode.

The ratio of the load value (40% load value) when the substrate particles are compressed by 40% to the load value (10% load value) at 10% compression (40% load value / 10% load value) is preferably 6 Hereinafter, it is more preferably 5 or less. When the ratio (40% load value / 10% load value) is equal to or less than the above upper limit, the design range for improving the connection reliability is further widened. When the ratio (40% load value / 10% load value) is equal to or less than the above upper limit, the connection resistance is effectively lowered. The above ratio (40% load value/10% load value) is preferably 2 or more.

The above-mentioned load value of the substrate particles and the above-mentioned compressive elastic modulus (10% K value and The 30% K value can be measured in the following manner.

The substrate particles were compressed on a smooth indenter end face of a cylinder (100 μm in diameter, made of diamond) at 25 ° C, a compression speed of 0.3 mN/sec, and a maximum test load of 20 mN using a micro compression tester. The load value (N) and the compression displacement (mm) at this time were measured. The above-described compression elastic modulus can be obtained from the measured value obtained by the following formula. For example, "Fischerscope H-100" manufactured by Fischer Co., Ltd. or the like can be used as the above-described micro compression tester.

10% K value or 30% K value (N/mm ² ) = (3/2 ^1/2 )‧F‧S ^-3/2 ‧R ^-1/2

F: load value when the substrate particles are subjected to 10% or 30% compression deformation (N)

S: compression displacement (mm) when the substrate particles are subjected to 10% or 30% compression deformation

R: radius of the substrate particles (mm)

The above-described compression elastic modulus generally and quantitatively indicates the hardness of the substrate particles. By using the above-described compression elastic modulus, the hardness of the substrate particles can be quantitatively and specifically expressed.

The fracture strain of the substrate particles is 10% or more and 30% or less. When evaluating the compression behavior of the particles, the time at which the displacement amount largely changes at a certain fixed load value is observed. The load value at the time of the change is the rupture load value, and the displacement amount is the rupture displacement. The ratio of the fracture displacement to the particle diameter before compression (fracture displacement/particle diameter before compression) × 100 was defined as the fracture strain (%). For example, when a particle having a particle diameter of 5 μm before compression is observed at a displacement of 1 μm, the fracture strain is calculated to be 20%. In the case of core-shell particles, the cracking behavior of the shell is usually observed at the beginning of the displacement. When the rupture strain is at least the above lower limit, the adhesiveness of the binder resin, the penetration of the conductive layer and the oxide film of the electrode are further increased, and the connection resistance is further lowered. When the rupture strain is at most the above upper limit, the flexibility in the middle stage is exhibited, and the contact area between the conductive particles and the electrode is further increased, and the connection resistance is further lowered.

The above-mentioned rupture strain can be evaluated based on the measurement of the above-described compression elastic modulus, and can be measured by reading the displacement amount of the non-joining point of the compression displacement curve.

The particle diameter of the core is preferably 0.5 μm or more, more preferably 1 μm or more, and is preferably 500 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less, still more preferably 20 μm or less, and most preferably 10 μm or less. When the particle diameter of the core is not less than the above lower limit and not more than the above upper limit, the 10% K value, the 30% K value, the above ratio (30% load value/10% load value), and the above ratio (40% load value/10%) The load value is easy to display a preferable value, and the substrate particles can be preferably used for the use of the conductive particles. For example, when the particle diameter of the core is not less than the above lower limit and not more than the above upper limit, when the electrodes are connected between the electrodes by using the conductive particles, the contact area between the conductive particles and the electrode is sufficiently increased, and when the conductive layer is formed It becomes difficult to form agglomerated conductive particles. Moreover, the interval between the electrodes connected via the conductive particles does not become excessively large, and the conductive layer becomes difficult to peel off from the surface of the substrate particles.

The particle diameter of the above-mentioned core means a diameter when the core is a true spherical shape, and when the core is a shape other than a true spherical shape, it means a diameter assumed to be a true sphere corresponding to its volume. Further, the particle diameter of the core means an average particle diameter obtained by measuring a core by an arbitrary particle diameter measuring device. For example, a particle size distribution measuring machine using the principles of laser light scattering, resistance value change, and image analysis after photographing can be used.

The substrate particles have a core and a shell disposed on the surface of the core, and are core-shell particles. The compression recovery ratio of the core-shell particles, the 10% K value, the 30% K value, the above ratio (30% load value/10% load value), and the above ratio (40% load value/10% load value) satisfy the above values. Thereby, the connection resistance between the electrodes can be reduced, and the connection reliability between the electrodes can be improved.

The above core is preferably an organic core. The above shell is preferably an inorganic shell. Preferably, the core is an organic core, and the shell is an inorganic shell. The substrate particles are preferably core-shell particles having an organic core and an inorganic shell disposed on the surface of the organic core, and are preferably core-shell type organic-inorganic hybrid particles. If the core is an organic core and the shell is an inorganic shell, the compression recovery rate, the 10% K value, the 30% K value, the above ratio (30% load value / 10% load value), and the above ratio (40% load) The value / 10% load value) easily satisfies the above values.

The above core is preferably an organic core, and is preferably an organic particle. The above organic core and the above Since the organic particles are relatively soft compared with the inorganic core and the inorganic particles, a shell is formed on the surface of the relatively soft organic core, and as a result, the compression recovery ratio, the above ratio (30% load value/10% load value), and the above ratio are easily satisfied. (40% load value / 10% load value).

As the material for forming the above organic core, various organic substances can be preferably used. As a material for forming the above organic core, for example, a polyolefin resin such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polypropylene, polyisobutylene or polybutadiene can be used; Acrylic resin such as methyl methacrylate or polymethyl acrylate; polyalkylene terephthalate, polyfluorene, polycarbonate, polyamine, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, A urea-formaldehyde resin and a polymer obtained by polymerizing one or two or more kinds of polymerizable monomers having an ethylenically unsaturated group. By polymerizing one or two or more kinds of polymerizable monomers having an ethylenically unsaturated group, it is easy to design and synthesize a substrate particle having a physical property at any compression suitable for a conductive material.

When the monomer having an ethylenically unsaturated group is polymerized to obtain the organic nucleus, the monomer having an ethylenically unsaturated group may be a non-crosslinkable monomer and a crosslinkable monomer.

Examples of the non-crosslinkable monomer include a styrene monomer such as styrene or α-methylstyrene, and a carboxyl group such as (meth)acrylic acid, maleic acid or maleic anhydride. Monomer; methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (methyl) ) lauryl acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) acrylate Alkyl (meth) acrylate such as ester; 2-hydroxyethyl (meth) acrylate, glyceryl (meth) acrylate, polyoxyethylene (meth) acrylate, glycidyl (meth) acrylate, etc. (meth) acrylate containing oxygen atom; nitrile containing monomer such as (meth) acrylonitrile; vinyl ether such as methyl vinyl ether, ethyl vinyl ether or propyl vinyl ether; vinyl acetate , vinyl acetate such as vinyl butyrate, vinyl laurate, vinyl stearate; unsaturated hydrocarbons such as ethylene, propylene, isoprene, butadiene; trifluoromethyl (meth)acrylate, A halogen-containing monomer such as pentafluoroethyl methacrylate, vinyl chloride, vinyl fluoride or chlorostyrene.

Examples of the crosslinkable monomer include tetramethylol methane tetra(meth)acrylate, tetramethylol methane tri(meth)acrylate, and tetramethylolmethane di(meth)acrylate. Ester, trimethylolpropane tri(meth) acrylate, dipentaerythritol hexa(meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri(meth) acrylate, glycerol di(methyl) Acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, (poly)1,4-butanediol di(meth)acrylate, 1,4 - Polyfunctional (meth) acrylates such as butanediol di(meth) acrylate; triallyl (iso) cyanurate, triallyl trimellitate, divinyl benzene, phthalic acid Allyl ester, diallyl acrylamide, diallyl ether, γ-(meth) propylene methoxy propyl trimethoxy decane, trimethoxy decyl styrene, vinyl trimethoxy decane, etc. Decane monomer and the like.

The above organic nucleus can be obtained by polymerizing the above polymerizable monomer having an ethylenically unsaturated group by a known method. Examples of the method include a method in which suspension polymerization is carried out in the presence of a radical polymerization initiator, and a method in which a non-crosslinked seed particle is swollen with a radical polymerization initiator to polymerize the monomer.

Particularly with regard to the present invention most suitable for the nuclear, nuclear above compression modulus of elasticity (10% K value) is preferably 1500N / mm ² and not more than 4000N / mm ² or less 10%, more preferably 2000N / mm ² Above and 3500N/mm ² or less. The compression recovery ratio of the above core is preferably 50% or more, more preferably 55% or more. If the above-mentioned core satisfies the above-mentioned 10% K value and satisfies the above-mentioned compression elastic modulus, it is easy to set the 10% K value of the above-mentioned core-coated substrate particles, and the above ratio (10% load value / 30% load value) ), and compression recovery rate control is a better range.

The method of designing the physical properties of the core to the above range is not limited. For example, when a monomer having an ethylenically unsaturated group is polymerized to obtain the above-mentioned core, 50% by weight or more of (meth) is used. A crosslinkable monomer having a flexible structure such as an ethylene glycol structure or a methylene structure between the acryl groups serves as a method for forming a compound of the core. Examples of such a crosslinkable monomer include (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, and (poly)tetramethylene di(methyl). Acrylate and 1,4-butanediol di(meth)acrylate. In the core obtained by using 70% by weight or more of a crosslinkable monomer having a rigid structure such as divinylbenzene, the 10% K value tends to become high. Further, even if a decane coupling agent such as vinyltrimethoxydecane or (meth)acryloxytrimethoxydecane is subjected to polycondensation by a sol-gel method, the particulate matter absorbed by the particles is absorbed by ethylene. After the monomer of the unsaturated group, the particles obtained by the polymerization may be designed to have the optimum physical properties. The material constituting the core may contain not only an organic compound but also a compound having a ruthenium atom. The ratio of the content of the carbon atom in the core to the content of the ruthenium atom (the content of the carbon atom / the content of the ruthenium atom) is preferably 1.2 or more. The nucleus in which the ratio (content of carbon atoms / content of ruthenium atoms) is 1.2 or more corresponds to an organic nucleus.

The decomposition temperature of the core is preferably more than 200 ° C, more preferably more than 250 ° C, and still more preferably more than 300 ° C from the viewpoint of forming a shell and suppressing deformation of the core when the substrate particles are used. The decomposition temperature of the above core may exceed 400 ° C, may exceed 500 ° C, may exceed 600 ° C, and may exceed 800 ° C.

The substrate particles are core-shell particles. The shell system is disposed on the surface of the core. Preferably, the shell covers the surface of the core. The above shell is preferably an inorganic shell.

The inorganic shell preferably contains 50% by weight or more of ruthenium atoms. In this case, the inorganic shell contains an inorganic shell containing a ruthenium atom as a main component. The inorganic shell may also contain carbon atoms, but when it contains a carbon atom, it is also called an inorganic shell as long as it is a main component.

The inorganic shell is preferably formed by baking a metal alkoxide on a surface of the core by a sol-gel method and then baking the shell. In the sol-gel method, a shell is easily disposed on the surface of the core. In the case of performing the above-described baking, in the substrate particles, the core is not removed by volatilization or the like after firing. The substrate particles have the core described above after firing. Furthermore, if it is assumed that the above-mentioned core is used after the roasting When the hair is removed, the above 10% K value becomes quite low.

The specific method of the sol-gel method is carried out by allowing an inorganic monomer such as tetraethoxysilane to coexist in a dispersion containing a solvent such as a core, water or alcohol, a surfactant, and a catalyst such as an aqueous ammonia solution. Method for interfacial sol reaction; and method for sol-gel reaction of a sol-gel reactant by a sol-gel reaction by an inorganic monomer such as tetraethoxy decane coexisting with a solvent such as water or an alcohol or an aqueous ammonia solution Wait. In the above sol-gel method, the metal alkoxide is preferably subjected to hydrolysis and polycondensation.

In the above sol-gel method, a surfactant is preferably used. Preferably, the metal alkoxide is formed into a shell by a sol-gel method in the presence of a surfactant. The above surfactant is not particularly limited. The above surfactant can be suitably selected to form a good shell. Examples of the surfactant include a cationic surfactant, an anionic surfactant, and a nonionic surfactant. Among them, a cationic surfactant is preferred in that a good inorganic shell can be formed.

Examples of the cationic surfactant include a quaternary ammonium salt and a quaternary phosphonium salt. Specific examples of the above cationic surfactant include cetyl ammonium bromide and the like.

In order to form the above inorganic shell on the surface of the above core, it is preferred to calcine the above shell. The degree of crosslinking in the inorganic shell can be adjusted depending on the firing conditions. Further, by baking, the 10% K value and the 30% K value of the substrate particles showed a further preferable value as compared with the case where the baking was not performed. In particular, by increasing the degree of crosslinking, the 10% K value is sufficiently high.

Preferably, the inorganic shell is formed by forming a metal alkoxide into a shell by a sol-gel method on the surface of the core, and then baking the shell at 100 ° C or higher (calcination temperature) to form a shell. . The calcination temperature is more preferably 150 ° C or higher, and still more preferably 200 ° C or higher. When the calcination temperature is at least the above lower limit, the degree of crosslinking in the inorganic shell is further moderated, and the 10% K value, the 30% K value, the above ratio (30% load value/10% load value), and the above ratio ( 40% load value / 10% load value) shows a further preferred value, which can be further preferably The substrate particles are used for the use of conductive particles.

Preferably, the inorganic shell is formed by forming a metal alkoxide into a shell by a sol-gel method on the surface of the core, and then the shell is subjected to a decomposition temperature (calcination temperature) of the organic core. It is formed by baking. The calcination temperature is preferably a temperature lower than the decomposition temperature of the core by 10 ° C or higher, and more preferably a temperature lower than the decomposition temperature of the core by 50 ° C or higher. Further, the baking temperature is preferably 500 ° C or lower, more preferably 300 ° C or lower, and still more preferably 200 ° C or lower. When the baking temperature is not more than the above upper limit, thermal deterioration and deformation of the core can be suppressed, and a 10% K value, a 30% K value, the above ratio (30% load value/10% load value), and the above ratio can be obtained ( 40% load value / 10% load value) substrate particles showing good values.

Examples of the metal alkoxide include a decane oxide, a titanium alkoxide, a zirconium alkoxide, and an aluminoxane. The metal alkoxide is preferably a decane oxide, a titanium alkoxide, a zirconium alkoxide or an aluminum alkoxide, more preferably a decane oxide or a titanium alkoxide, from the viewpoint of forming a good inorganic shell. Or a zirconium alkoxide, more preferably a decane oxide. From the viewpoint of forming a good inorganic shell, the metal atom in the above metal alkoxide is preferably a ruthenium atom, a titanium atom, a zirconium atom or an aluminum atom, more preferably a ruthenium atom, a titanium atom or a zirconium atom, and further Jia is a scorpion atom. The metal alkoxide may be used alone or in combination of two or more.

The metal alkoxide is preferably a metal alkoxide represented by the following formula (1) from the viewpoint of forming a good inorganic shell.

M(R1) _n (OR2) _4-n (1)

In the above formula (1), M is a halogen atom, a titanium atom or a zirconium atom, and R1 represents a phenyl group, an alkyl group having 1 to 30 carbon atoms, an organic group having a carbon number of 1 to 30 having a polymerizable double bond, or an epoxy group. The organic group having a carbon number of 1 to 30, R2 represents an alkyl group having 1 to 6 carbon atoms, and n represents an integer of 0 to 2. When n is 2, a plurality of R1s may be the same or different. A plurality of R2s may be the same or different.

The metal alkoxide is preferably a decane oxide represented by the following formula (1A) from the viewpoint of forming a good inorganic shell.

Si(R1) _n (OR2) _4-n (1A)

In the above formula (1A), R1 represents a phenyl group, an alkyl group having 1 to 30 carbon atoms, an organic group having a carbon number of 1 to 30 having a polymerizable double bond, or an organic group having 1 to 30 carbon atoms having an epoxy group. R2 represents an alkyl group having 1 to 6 carbon atoms, and n represents an integer of 0 to 2. When n is 2, a plurality of R1s may be the same or different. A plurality of R2s may be the same or different. In order to effectively increase the content of the ruthenium atoms contained in the shell, n in the above formula (1A) preferably represents 0 or 1, more preferably 0. When the content of the ruthenium atoms contained in the shell is high, the effects of the present invention are further excellent.

In the case where R1 is an alkyl group having 1 to 30 carbon atoms, specific examples of R1 include methyl group, ethyl group, propyl group, isopropyl group, isobutyl group, n-hexyl group, cyclohexyl group, and n-octyl group. Base, and positive base. The carbon number of the alkyl group is preferably 10 or less, more preferably 6 or less. Further, the alkyl group contains a cycloalkyl group.

The polymerizable double bond may, for example, be a carbon-carbon double bond. In the case where the above R1 is an organic group having a carbon number of 1 to 30 having a polymerizable double bond, examples of R1 include a vinyl group, an allyl group, an isopropenyl group, and a 3-(meth)acryl oxime. Oxyalkyl and the like. Examples of the (meth)acryloxyalkylene group include (meth)acryloxymethyl group, (meth)acryloxyethyl group, and (meth)acryloxypropyl group. The carbon number of the organic group having 1 to 30 carbon atoms having a polymerizable double bond is preferably 2 or more, and is preferably 30 or less, more preferably 10 or less. The above "(meth)acryloxy group" means a methacryloxy group or an acryloxy group.

In the case where the above R1 is an organic group having an epoxy group having 1 to 30 carbon atoms, specific examples of R1 include 1,2-epoxyethyl group and 1,2-epoxypropyl group. 2,3-epoxypropyl, 3,4-epoxybutyl, 3-glycidoxypropyl, and 2-(3,4-epoxycyclohexyl)ethyl, and the like. The carbon number of the organic group having 1 to 30 carbon atoms having an epoxy group is preferably 8 or less, more preferably 6 or less. Further, the organic group having 1 to 30 carbon atoms having an epoxy group contains a group derived from an oxygen atom derived from an epoxy group in addition to a carbon atom and a hydrogen atom.

Specific examples of the above R2 include a methyl group, an ethyl group, a n-propyl group, an isopropyl group, an n-butyl group, and an isobutyl group. In order to effectively increase the content of the ruthenium atoms contained in the shell, the above R2 preferably represents a methyl group or an ethyl group.

Specific examples of the above decane oxide include tetramethoxy decane, tetraethoxy decane, methyl trimethoxy decane, methyl triethoxy decane, ethyl trimethoxy decane, and ethyl triethyl ethane. Oxy decane, isopropyl trimethoxy decane, isobutyl trimethoxy decane, cyclohexyl trimethoxy decane, n-hexyl trimethoxy decane, n-octyl triethoxy decane, n-decyl trimethoxy decane And phenyltrimethoxydecane, dimethyldimethoxydecane, and diisopropyldimethoxydecane. It is also possible to use decane oxides other than these.

In order to effectively increase the content of the ruthenium atoms contained in the shell, it is preferred to use tetramethoxy decane or tetraethoxy decane as the material of the above shell. The total content of tetramethoxy decane and tetraethoxy decane in 100% by weight of the material of the shell is preferably 50% by weight or more (may also be the total amount). In 100% by weight of the shell, the total content of the skeleton derived from tetramethoxynonane and the skeleton derived from tetraethoxysilane is preferably 50% by weight or more (may also be the total amount).

Specific examples of the titanium alkoxide include titanium tetramethoxide, titanium tetraethoxy oxide, titanium tetraisopropyl oxide, and titanium tetrabutyl oxide. Titanium alkoxides other than these may also be used.

Specific examples of the zirconium alkoxide include zirconium tetramethoxide, zirconium tetraethoxy oxide, zirconium tetraisopropoxide, and zirconium tetrabutoxide. Zirconium alkoxides other than these may also be used.

The metal alkoxide is preferably a metal alkoxide having a structure in which four oxygen atoms are directly bonded to a metal atom. The metal alkoxide preferably contains a metal alkoxide represented by the following formula (1a).

M(OR2) ₄ (1a)

In the above formula (1a), M is a halogen atom, a titanium atom or a zirconium atom, and R2 represents an alkyl group having 1 to 6 carbon atoms. A plurality of R2s may be the same or different.

The metal alkoxide preferably contains a decane oxide having a structure in which a halogen atom is directly bonded to four atoms. In the decane oxide, usually four oxygen atoms are bonded to a ruthenium atom by a single bond. The metal alkoxide preferably contains a decane oxide represented by the following formula (1Aa).

Si(OR2) ₄ (1Aa)

In the above formula (1Aa), R2 represents an alkyl group having 1 to 6 carbon atoms. A plurality of R2s may be the same or different.

In view of the fact that the 10% K value is effectively increased and the 30% K value is effectively lowered, in the above 100 mol% of the metal alkoxide for forming an inorganic shell, the above has a direct bond to the metal atom. a metal alkoxide having a structure of four oxygen atoms, a metal alkoxide represented by the above formula (1a), a decane oxide having a structure in which a halogen atom is directly bonded to four oxygen atoms, or the above formula ( The content of the decane oxide represented by 1Aa) is preferably 20 mol% or more, more preferably 40 mol% or more, still more preferably 50 mol% or more, and still more preferably 55 mol% or more. Preferably, it is 60% by mole or more, and is 100% by mole or less. The total amount of the metal alkoxide to form the inorganic shell may be the metal alkoxide having a structure in which four oxygen atoms are directly bonded to the metal atom, and the metal alkoxide represented by the above formula (1a) And a decane oxide having a structure in which a ruthenium atom is directly bonded to four oxygen atoms or a decane oxide represented by the above formula (1Aa).

From the viewpoint of effectively increasing the 10% K value and effectively lowering the 30% K value, the total number of metal atoms derived from the metal alkoxide contained in the inorganic shell is directly 100%. The ratio of the number of metal atoms having four oxygen atoms bonded to each other, the direct bonding of four -O-Si groups and the direct bonding of four atomic atoms of four of the above -O-Si groups The ratio of the number is preferably 20% or more, more preferably 40% or more, further preferably 50% or more, further preferably 55 mol% or more, and particularly preferably 60% or more.

Further, the 10% K value is appropriately increased, and the above ratio (30% load value/10% load value) and the above ratio (40% load value/10% load value) are controlled to an appropriate range. on In the total number of metal atoms contained in the inorganic shell, the ratio of the number of metal atoms directly bonded to four oxygen atoms is preferably 20% or more, more preferably 40% or more, and further preferably It is 50% or more, and more preferably 55 mol% or more, and particularly preferably 60% or more. The metal alkoxide is a decane oxide, and the above inorganic shell is made such that the 10% K value is appropriately increased and the above ratio (30% K value/10% K value) is controlled to an appropriate range. The ratio of the number of 矽 atoms in which four of the above-mentioned -O-Si groups are directly bonded to each other in the total number of 100% of the ruthenium atoms contained therein is directly bonded to four -O-Si groups. It is preferably 20% or more, more preferably 40% or more, further preferably 50% or more, further preferably 55% or more, and particularly preferably 60% or more.

Further, a germanium atom directly bonded to four-0-Si groups and directly bonded to four of the above-mentioned -O-Si groups is, for example, a structure represented by the following formula (11) Helium atom. Specifically, it is a germanium atom represented by an arrow A in the structure represented by the following formula (11X).

Further, the oxygen atom in the above formula (11) usually forms a decane bond with an adjacent ruthenium atom.

[Chemical 3]

The ratio of the number of Q atoms (4%) to the number of deuterium atoms having 4 -O-Si groups directly bonded to 4 of the above -O-Si groups The method for performing the measurement includes, for example, using Q4 (directly bonded to four -O-Si groups and directly bonded to four of the four -O-Si groups) using an NMR spectrum analyzer. The peak area of the ruthenium atom is the same as Q1~Q3 (1~3 -O-Si groups are directly bonded and 1~3 oxygen atoms in the above -O-Si group are directly bonded) The method of comparing the peak areas of atoms. By this method, it is found that 100% of the total number of germanium atoms contained in the inorganic shell is directly bonded to four -O-Si groups and directly bonded to four of the above -O-Si groups. The ratio of the number of 矽 atoms of the four oxygen atoms (the ratio of the number of Q4).

The thickness of the above shell is preferably 100 nm or more, more preferably 200 nm or more, and is preferably 5 μm or less, more preferably 3 μm or less. When the thickness of the shell is not less than the above lower limit and not more than the above upper limit, the 10% K value and the 30% K value show further preferable values, and the substrate particles can be preferably used for the use of the conductive particles. The thickness of the above shell is the average thickness of each of the substrate particles. The thickness of the above shell can be controlled by controlling the sol-gel method.

In the present invention, the thickness of the shell can be determined from the difference between the particle diameter of the substrate particles and the average value of the core particle diameter. The particle diameter of the substrate particles means a diameter when the substrate particles are in a true spherical shape, and when the substrate particles have a shape other than a true spherical shape, it means assuming a true ball equivalent to the volume thereof. The diameter. In the measurement of the particle size, for example, particle size distribution measurement using the principles of laser light scattering, resistance value change, and image analysis after photographing can be applied. machine.

The aspect ratio of the substrate particles is preferably 2 or less, more preferably 1.5 or less, still more preferably 1.2 or less. The above aspect ratio means long diameter/short diameter.

(conductive particles)

The conductive particles include the above-described substrate particles and a conductive layer disposed on the surface of the substrate particles.

The conductive particles according to the first embodiment of the present invention are shown in cross section in Fig. 1 .

The conductive particles 1 shown in FIG. 1 have substrate particles 11 and a conductive layer 2 disposed on the surface of the substrate particles 11. The conductive layer 2 covers the surface of the substrate particles 11. The conductive particles 1 are coated particles in which the surface of the substrate particles 11 is covered with the conductive layer 2 .

The substrate particles 11 include a core 12 and a shell 13 disposed on the surface of the core 12 . The shell 13 is coated with the surface of the core 12. The conductive layer 2 is disposed on the surface of the case 13. The conductive layer 2 is the surface of the covering case 13.

The conductive particles of the second embodiment of the present invention are shown in cross section in Fig. 2 .

The conductive particles 21 shown in FIG. 2 have substrate particles 11 and a conductive layer 22 disposed on the surface of the substrate particles 11. The conductive layer 22 has a first conductive layer 22A as an inner layer and a second conductive layer 22B as an outer layer. The first conductive layer 22A is disposed on the surface of the substrate particle 11. The first conductive layer 22A is disposed on the surface of the case 13. The second conductive layer 22B is disposed on the surface of the first conductive layer 22A.

Fig. 3 is a cross-sectional view showing conductive particles according to a third embodiment of the present invention.

The conductive particles 31 shown in FIG. 3 have a substrate particle 11, a conductive layer 32, a plurality of core materials 33, and a plurality of insulating materials 34.

The conductive layer 32 is disposed on the surface of the substrate particles 11. A conductive layer 32 is disposed on the surface of the shell 13.

The conductive particles 31 have a plurality of protrusions 31a on the surface of the conductivity. The conductive layer 32 has a plurality of protrusions 32a on the outer surface. As described above, the above conductive particles can be guided The electrically conductive surface has protrusions and may also have protrusions on the outer surface of the conductive layer. A plurality of core materials 33 are disposed on the surface of the substrate particles 11. A plurality of core materials 33 are disposed on the surface of the shell 13. A plurality of core materials 33 are embedded in the conductive layer 32. The core material 33 is disposed inside the protrusions 31a and 32a. The conductive layer 32 is coated with a plurality of core materials 33. The outer surfaces of the conductive layer 32 are embossed by the plurality of core materials 33, and the projections 31a, 32a are formed.

The conductive particles 31 have an insulating material 34 disposed on the outer surface of the conductive layer 32. At least a portion of the outer surface of the conductive layer 32 is covered with an insulating material 34. The insulating material 34 is formed of an insulating material and is an insulating particle. As described above, the conductive particles may have an insulating material disposed on the outer surface of the conductive layer.

The metal for forming the above conductive layer is not particularly limited. Examples of the metal include gold, silver, palladium, copper, platinum, zinc, antimony, tin, lead, aluminum, cobalt, indium, nickel, chromium, titanium, ruthenium, osmium, iridium, osmium, cadmium, and antimony. Such alloys and the like. Further, examples of the metal include tin-doped indium oxide (ITO), solder, and the like. Among them, since the connection resistance between the electrodes can be further lowered, an alloy containing tin, nickel, palladium, copper or gold is preferable, and nickel or palladium is preferable.

The conductive layer may be formed of one layer as in the case of the conductive particles 1 and 31. The conductive layer may be formed of a plurality of layers as in the case of the conductive particles 21. That is, the conductive layer may have a laminated structure of two or more layers. In the case where the conductive layer is formed of a plurality of layers, the outermost layer is preferably a gold layer, a nickel layer, a palladium layer, a copper layer or an alloy layer containing tin and silver, more preferably a gold layer. In the case where the outermost layer is such a preferred conductive layer, the connection resistance between the electrodes is further lowered. Further, when the outermost layer is a gold layer, the corrosion resistance is further increased.

A method of forming a conductive layer on the surface of the substrate particles is not particularly limited. Examples of the method of forming the conductive layer include a method using electroless plating, a method using electroplating, a method using physical vapor deposition, and a method of applying a metal powder or a paste containing a metal powder and a binder to a surface of a substrate particle. Method and so on. Among them, the method of electroless plating is preferred because the formation of the conductive layer is simple. As the above method using physical vapor deposition, Examples thereof include vacuum vapor deposition, ion plating, and ion sputtering.

The particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, and is preferably 520 μm or less, more preferably 500 μm or less, further preferably 100 μm or less, and still more preferably 50 μm or less, particularly preferably 20 μm or less. When the particle diameter of the conductive particles is not less than the above lower limit and not more than the above upper limit, when the electrodes are connected by using the conductive particles, the contact area between the conductive particles and the electrode is sufficiently increased, and the conductive layer is changed. It is difficult to form agglomerated conductive particles. Moreover, the interval between the electrodes connected via the conductive particles does not become excessively large, and the conductive layer becomes difficult to peel off from the surface of the substrate particles. Further, when the particle diameter of the conductive particles is not less than the above lower limit and not more than the above upper limit, the conductive particles can be preferably used for the use of the conductive material.

The particle diameter of the conductive particles means a diameter when the conductive particles are in a true spherical shape, and when the conductive particles are in a shape other than a true spherical shape, it means a diameter assuming a true ball corresponding to the volume thereof. .

The thickness of the conductive layer is preferably 0.005 μm or more, more preferably 0.01 μm or more, and is preferably 10 μm or less, more preferably 1 μm or less, still more preferably 0.3 μm or less. The thickness of the conductive layer is the thickness of the entire conductive layer when the conductive layer is a plurality of layers. When the thickness of the conductive layer is not less than the above lower limit and not more than the above upper limit, sufficient conductivity is obtained, and the conductive particles are not excessively hard, and the conductive particles are sufficiently deformed when the electrodes are connected.

When the conductive layer is formed of a plurality of layers, the thickness of the outermost conductive layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, and is preferably 0.5 μm or less, more preferably 0.1 μm or less. When the thickness of the outermost conductive layer is not less than the above lower limit and not more than the above upper limit, the coating of the outermost conductive layer becomes uniform, and the corrosion resistance is sufficiently high, and the connection resistance between the electrodes is further lowered. Further, in the case where the outermost layer is a gold layer, the thinner the thickness of the gold layer, the lower the cost.

The thickness of the above conductive layer can be observed, for example, by using a transmission electron microscope (TEM). The cross section of the conductive particles was measured and measured.

The conductive particles may have protrusions on the surface of the conductivity. The conductive particles may have protrusions on the outer surface of the conductive layer. The protrusions are preferably plural. In many cases, an oxide film is formed on the surface of the conductive layer and the surface of the electrode to which the conductive particles are connected. When the conductive particles having protrusions are used, the conductive particles are placed between the electrodes and pressure-bonded, whereby the oxide film is effectively removed by the protrusions. Therefore, the electrode and the conductive layer of the conductive particles can be further reliably contacted, and the connection resistance between the electrodes can be lowered. Further, when the conductive particles have an insulating material on the surface or when the conductive particles are dispersed in the binder resin and used as a conductive material, the conductive particles can be effectively removed by the protrusions of the conductive particles. An insulating substance or a binder resin between the particles and the electrode. Therefore, the conduction reliability between the electrodes can be improved.

The method of forming a protrusion on the surface of the conductive particle includes a method of forming a conductive layer by electroless plating after attaching a core substance to a surface of a substrate particle, and electroless plating on a surface of the substrate particle. After the conductive layer is formed, a core material is adhered, and a conductive layer is formed by electroless plating. Moreover, in order to form a protrusion, the above-mentioned core substance may not be used.

The conductive particles may further include an insulating material disposed on the outer surface of the conductive layer. In this case, when the conductive particles are used for the connection between the electrodes, the short circuit between the adjacent electrodes can be prevented. Specifically, when a plurality of conductive particles are in contact with each other, an insulating material is present between the plurality of electrodes. Therefore, it is possible to prevent short-circuiting between the electrodes adjacent in the lateral direction, and is not a short circuit between the upper and lower electrodes. Further, when the electrodes are connected, the conductive particles are pressurized by the two electrodes, whereby the insulating material between the conductive layers of the conductive particles and the electrodes can be easily removed. When the conductive particles have protrusions on the surface of the conductive layer, the insulating material between the conductive layer of the conductive particles and the electrode can be further easily removed. The insulating material is preferably an insulating resin layer or insulating particles, and more preferably insulating particles. The insulating particles are preferably insulating resin particles.

(conductive material)

The conductive material contains the above-mentioned conductive particles and a binder resin. The conductive particles are preferably dispersed in a binder resin and used as a conductive material. The above conductive material is preferably an anisotropic conductive material. The above conductive material can be preferably used for electrical connection of electrodes. The above conductive material is preferably a circuit connecting material.

The above binder resin is not particularly limited. As the above-mentioned binder resin, a known insulating resin can be used. Examples of the binder resin include a vinyl resin, a thermoplastic resin, a curable resin, a thermoplastic block copolymer, and an elastomer. The binder resin may be used alone or in combination of two or more.

Examples of the vinyl resin include a vinyl acetate resin, an acrylic resin, and a styrene resin. Examples of the thermoplastic resin include a polyolefin resin, an ethylene-vinyl acetate copolymer, and a polyamide resin. Examples of the curable resin include an epoxy resin, a urethane resin, a polyimide resin, and an unsaturated polyester resin. Further, the curable resin may be a room temperature curing resin, a thermosetting resin, a photocurable resin or a moisture curing resin. The curable resin may be used in combination with a curing agent. Examples of the above thermoplastic block copolymer include a styrene-butadiene-styrene block copolymer, a styrene-isoprene-styrene block copolymer, and a styrene-butadiene-styrene. a hydride of a block copolymer, a hydride of a styrene-isoprene-styrene block copolymer, and the like. Examples of the elastomer include a styrene-butadiene copolymer rubber and an acrylonitrile-styrene block copolymer rubber.

The conductive material may contain, in addition to the conductive particles and the binder resin, a filler, a bulking agent, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, and a heat stabilizer. Various additives such as agents, light stabilizers, ultraviolet absorbers, lubricants, antistatic agents and flame retardants.

The method of dispersing the above-mentioned conductive particles in the above-mentioned binder resin can be a conventionally known dispersion method, and is not particularly limited. Dispersing the above conductive particles in the above For the method of the binder resin, for example, a method in which the conductive particles are added to the binder resin and then kneaded by a planetary mixer or the like is dispersed, and the conductive particles are uniformly used by using a homogenizer or the like. After being dispersed in water or an organic solvent, it is added to the above-mentioned binder resin, and is kneaded by a planetary mixer or the like to be dispersed, and the above-mentioned binder resin is diluted with water or an organic solvent to add the above conductivity. A method in which particles are kneaded by a planetary mixer or the like and dispersed.

The above conductive material can be used as a conductive paste, a conductive film, or the like. When the conductive material of the present invention is a conductive film, a film containing no conductive particles may be laminated on the conductive film containing the conductive particles. The above conductive paste is preferably an anisotropic conductive paste. The above conductive film is preferably an anisotropic conductive film.

The content of the binder resin is preferably 10% by weight or more, more preferably 30% by weight or more, still more preferably 50% by weight or more, particularly preferably 70% by weight or more, and more preferably 100% by weight of the conductive material. It is 99.99% by weight or less, more preferably 99.9% by weight or less. When the content of the binder resin is not less than the above lower limit and not more than the above upper limit, the conductive particles are efficiently disposed between the electrodes, and the connection reliability of the member to be joined connected by the conductive material is further increased.

The content of the conductive particles in 100% by weight of the conductive material is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and is preferably 40% by weight or less, more preferably 20% by weight or less, and further preferably It is 10% by weight or less. When the content of the conductive particles is not less than the above lower limit and not more than the above upper limit, the conduction reliability between the electrodes is further increased.

(connection structure)

The connection structure is obtained by using the above-described conductive particles or a conductive material containing the above-described conductive particles and a binder resin, whereby a connection structure can be obtained.

Preferably, the connection structure includes a first connection target member and a second connection object structure. And a connecting portion that connects the first connection target member and the second connection target member, and the connection portion is formed of the conductive particles described above or a conductive material containing the conductive particles and the binder resin. In the case where the conductive particles are used alone, the connecting portion itself is a conductive particle. In other words, the first and second connection target members are connected by conductive particles. The above conductive material for obtaining the above-mentioned connection structure is preferably an anisotropic conductive material.

Preferably, the first connection target member has a first electrode on the surface. Preferably, the second connection target member has a second electrode on the surface. Preferably, the first electrode and the second electrode are electrically connected by the conductive particles.

Fig. 4 is a front cross-sectional view schematically showing a connection structure using the conductive particles 1 shown in Fig. 1 .

The connection structure body 51 shown in FIG. 4 includes the first connection object member 52, the second connection object member 53, and the connection portion 54 that connects the first connection object member 52 and the second connection object member 53. The connecting portion 54 is formed of a conductive material containing the conductive particles 1 and a binder resin. In Fig. 4, the conductive particles 1 are simply shown for convenience of illustration. In addition to the conductive particles 1, other conductive particles such as conductive particles 21 and 31 may be used.

The first connection target member 52 has a plurality of first electrodes 52a on the front surface (upper surface). The second connection target member 53 has a plurality of second electrodes 53a on the front surface (lower surface). The first electrode 52a and the second electrode 53a are electrically connected to one or a plurality of conductive particles 1. Therefore, the first and second connection object members 52 and 53 are electrically connected by the conductive particles 1 .

The method for producing the above-described connection structure is not particularly limited. An example of the method of manufacturing the connection structure is a method in which the conductive material is placed between the first connection target member and the second connection target member to obtain a laminate, and the laminate is heated and pressurized. The pressure of the above pressurization is about 9.8 × 10 ⁴ to 4.9 × 10 ⁶ Pa. The heating temperature is about 120 to 220 °C. The pressure of the pressurization of the electrode for connecting the flexible printed circuit board, the electrode disposed on the resin film, and the electrode of the touch panel is about 9.8×10 ⁴ to 1.0×10 ⁶ Pa.

Specific examples of the connection target member include electronic components such as a semiconductor wafer, a capacitor, and a diode, and electronic components such as a printed circuit board, a flexible printed circuit board, a glass substrate such as a glass substrate, and a glass substrate. The conductive material is preferably a conductive material for connecting electronic components. The conductive paste is preferably a paste-like conductive material and is applied to the member to be joined in a paste state.

The conductive particles and the conductive material described above can also be preferably used for a touch panel. Therefore, the connection target member is preferably a flexible printed circuit board or a connection target member in which an electrode is disposed on the surface of the resin film. The connection target member is preferably a flexible printed circuit board, and is preferably a connection target member in which an electrode is disposed on the surface of the resin film. The above flexible printed substrate usually has electrodes on its surface.

In particular, in the present invention, in order to suppress damage of the conductive particles to the member to be bonded such as the substrate, the initial hardness of the substrate particles is designed to be in an appropriate range. Therefore, in the present invention, the surface of the electrode is a metal which is easily oxidized such as titanium or molybdenum, or a glass substrate (having a thickness of about 0.2 mm) having a relatively small thickness is connected to the semiconductor wafer, or the flexible printed substrate and the semiconductor are bonded. When the wafer is connected, it exerts a large effect.

The combination of the first and second connection members is preferably a combination of a glass substrate or a flexible printed substrate and a semiconductor wafer, preferably a combination of a glass substrate and a semiconductor wafer, and is preferably a combination of a flexible printed substrate and a semiconductor wafer. In this case, the first connection member may be a glass substrate or a flexible printed substrate, and the second connection member may be a glass substrate or a flexible printed substrate. The thickness of the glass substrate is 0.05 mm or more and less than 0.5 mm.

Examples of the electrode provided in the connection target member include metal electrodes such as a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a molybdenum electrode, a tungsten electrode, and a titanium electrode. In the case where the connection target member is a flexible printed circuit board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode or a copper electrode. In the case where the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode or a tungsten electrode. again When the electrode is an aluminum electrode, the electrode may be an electrode formed only of aluminum, or may be an electrode formed on a surface layer of a metal oxide layer. Examples of the material of the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al, Ga, and the like.

Preferably, at least one of the first and second electrodes is a titanium electrode or a molybdenum electrode, and preferably both of the first and second electrodes are titanium electrodes or molybdenum electrodes. It is preferable that at least one of the materials constituting the surfaces of the first and second electrodes contains titanium or molybdenum, and it is more preferable that both of the materials constituting the surfaces of the first and second electrodes contain titanium or molybdenum.

Hereinafter, the present invention will be specifically described by way of examples and comparative examples. The invention is not limited to the following examples.

(Example 1)

(1) Fabrication of substrate particles

Nuclear production)

950 parts by weight of 1,4-butanediol diacrylate and 50 parts by weight of ethylene glycol dimethacrylate were mixed to obtain a mixed liquid. 20 parts by weight of benzamidine peroxide was added to the obtained mixed solution, and the mixture was stirred until homogeneously dissolved to obtain a monomer mixture. 4000 parts by weight of a 2% by weight aqueous solution of polyvinyl alcohol having a molecular weight of about 1700 dissolved in pure water was placed in the reaction vessel. The obtained monomer mixture liquid was added thereto, and stirred for 4 hours, whereby the particle diameter was adjusted so that the droplets of the monomer became a specific particle diameter. Thereafter, the reaction was carried out for 9 hours under a nitrogen atmosphere at 85 ° C to carry out polymerization of monomer droplets to obtain particles. The obtained particles are washed several times with hot water, and then subjected to a classification operation to recover a plurality of polymer particles (organic cores) having different particle diameters.

Among the polymer particles recovered by the classification operation in Example 1, polymer particles (organic core) having a particle diameter of 2.49 μm were prepared.

Production of core-shell particles)

30 parts by weight of the obtained polymer particles (organic core) as a surfactant 12 parts by weight of an alkylammonium bromide and 24 parts by weight of an aqueous ammonia solution of 25% by weight were added to 540 parts by weight of isopropyl alcohol and 60 parts by weight of pure water, and mixed to obtain a dispersion of polymer particles. 140 parts by weight of tetraethoxysilane was added to the dispersion to carry out a condensation reaction by a sol-gel reaction. The condensate of tetraethoxydecane is precipitated on the surface of the polymer particles to form a shell to obtain particles. The obtained particles were washed several times with ethanol and dried to obtain core-shell particles (substrate particles). The particle size of the obtained core-shell particles was 3.01 μm. The thickness of the shell was calculated to be 0.26 μm from the particle diameter of the core and the particle diameter of the core-shell particles.

(2) Production of conductive particles

The obtained substrate particles are washed and dried. Thereafter, a nickel layer was formed on the surface of the obtained substrate particles by an electroless plating method to prepare conductive particles. Further, the thickness of the nickel layer was 0.1 μm.

(Example 2)

Among the polymer particles recovered by the classification operation in Example 1, polymer particles (organic core) having a particle diameter of 2.25 μm were prepared. The core-shell particles and the conductive particles were obtained in the same manner as in Example 1 except that the polymer particles obtained were used and the amount of the tetraethoxysilane was changed to 310 parts by weight in the production of the core-shell particles. .

(Example 3)

The substrate particles obtained in Example 1 were heat-treated at 200 ° C for 30 minutes in an electric furnace under nitrogen filling. Thereafter, conductive particles were produced by the same treatment as in Example 1.

(Example 4)

(1) Palladium attachment step

The substrate particles obtained in Example 1 were prepared. The obtained substrate particles were etched and washed with water. Then, the substrate particles were added to 100 mL of a palladium catalyst solution containing 8 wt% of a palladium catalyst and stirred. Thereafter, it was filtered and washed. The substrate particles were added to a 0.5 wt% dimethylamine borane solution having a pH of 6, to obtain a substrate particle to which palladium adhered.

(2) Core substance attachment step

The substrate particles to which palladium adhered were stirred in 300 mL of ion-exchanged water for 3 minutes, and dispersed to obtain a dispersion. Then, 1 g of a metal nickel particle paste (average particle diameter: 100 nm) was added to the above dispersion liquid for 3 minutes to obtain a substrate particle to which a core substance adhered.

(3) Electroless nickel plating step

A nickel layer was formed on the surface of the substrate particles in the same manner as in Example 1 to prepare conductive particles. Further, the thickness of the nickel layer was 0.1 μm.

(Example 5)

(1) Production of insulating particles

To a 1000 mL separable flask equipped with four separable caps, stirring blades, three-way cocks, cooling tubes and temperature probes, 100 mmol of methyl methacrylate, N, N, N-trimethyl a monomer composition of 1 mmol of -N-2-methylpropenyloxyethylamine chloride and 1 mmol of 2,2'-azobis(2-amidinopropane) dihydrochloride was obtained as a solid component ratio After weighing into 5 parts by weight of the ion-exchanged water, the mixture was stirred at 200 rpm, and polymerization was carried out at 70 ° C for 24 hours under a nitrogen atmosphere. After completion of the reaction, lyophilization was carried out to obtain insulating particles having an ammonium group on the surface and having an average particle diameter of 220 nm and a CV value of 10%.

The insulating particles were dispersed in ion-exchanged water under ultrasonic irradiation to obtain a 10% by weight aqueous dispersion of the insulating particles.

10 g of the conductive particles obtained in Example 1 was dispersed in 500 mL of ion-exchanged water, 4 g of an aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 6 hours. After filtering by a 3 μm mesh filter, it was further washed with methanol and dried to obtain conductive particles to which insulating particles were attached.

Observation by a scanning electron microscope (SEM) revealed that only one coating layer using insulating particles was formed on the surface of the conductive particles. From the image analysis, the coverage area of the insulating particles with respect to the area of 2.5 μm from the center of the conductive particles (that is, the projected area of the particle diameter of the insulating particles) was calculated, and as a result, the coverage ratio was 30%.

(Example 6)

Among the polymer particles recovered by the classification operation in Example 1, polymer particles (organic core) having a particle diameter of 2.25 μm were prepared. When the obtained polymer particles and the core-shell particles were produced, 540 parts by weight of methanol was changed to 540 parts by weight of acetonitrile, and the amount of addition of tetraethoxysilane was changed to 310 parts by weight, and In the same manner as in Example 1, core-shell particles and conductive particles were obtained.

(Example 7)

Among the polymer particles fractionated and recovered in Example 1, polymer particles (organic core) having a particle diameter of 2.75 μm were prepared. When the obtained polymer particles and the core-shell particles were produced, 540 parts by weight of methanol was changed to 540 parts by weight of acetonitrile, and the amount of addition of tetraethoxysilane was changed to 50 parts by weight. In the same manner, core-shell particles and conductive particles were obtained.

(Comparative Example 1)

Among the polymer particles recovered by the classification operation in Example 1, polymer particles having a particle diameter of 3.02 μm were prepared. Conductive particles were obtained in the same manner as in Example 1 using the obtained polymer particles as substrate particles.

(Comparative Example 2)

In the production of the core, 950 parts by weight of 1,4-butanediol diacrylate and 50 parts by weight of ethylene glycol dimethacrylate are changed to divinylbenzene (purity: 96% by weight), 600 parts by weight, and acrylic acid Particles were obtained in the same manner as in Example 1 except for 400 parts by weight of the ester. The obtained particles are washed several times with hot water, and then subjected to a classification operation to recover a plurality of kinds of polymer particles having different particle diameters.

The polymer particles having a particle diameter of 3.00 μm among the polymer particles recovered by the classification operation in Comparative Example 2 were prepared. Conductive particles were obtained in the same manner as in Example 1 using the obtained polymer particles as substrate particles.

(Comparative Example 3)

In the production of the core, 950 parts by weight of 1,4-butanediol diacrylate and 50 parts by weight of ethylene glycol dimethacrylate are changed to 1000 parts by weight of divinylbenzene (purity: 96% by weight), and peroxidation is carried out. The particles were obtained in the same manner as in Example 1 except that the amount of the benzamidine added was changed to 40 parts by weight. The obtained particles are washed several times with hot water, and then subjected to a classification operation to recover a plurality of kinds of polymer particles having different particle diameters.

The polymer particles having a particle diameter of 3.01 μm among the polymer particles recovered by the classification operation in Comparative Example 3 were prepared. Conductive particles were obtained in the same manner as in Example 1 using the obtained polymer particles as substrate particles.

(Comparative Example 4)

In the production of the core, 950 parts by weight of 1,4-butanediol diacrylate and 50 parts by weight of ethylene glycol dimethacrylate are changed to 800 parts by weight of divinylbenzene (purity: 96% by weight) and 200 parts by weight of acrylonitrile. The particles were obtained in the same manner as in Example 1 except that the amount of the benzamidine peroxide added was changed to 40 parts by weight. The obtained particles are washed several times with hot water, and then subjected to a classification operation to recover a plurality of kinds of polymer particles having different particle diameters.

In the polymer particles recovered by the classification operation in Comparative Example 4, polymer particles having a particle diameter of 3.00 μm were prepared. Conductive particles were obtained in the same manner as in Example 1 using the obtained polymer particles as substrate particles.

(Comparative Example 5)

Among the polymer particles recovered by the classification operation in Example 1, polymer particles having a particle diameter of 3.01 μm were prepared. The core-shell particles and the conductive particles were obtained in the same manner as in Example 1 except that the obtained polymer particles were used, and the amount of the tetraethoxysilane was changed to 10 parts by weight in the production of the core-shell particles. .

(Evaluation)

(1) Particle size of the substrate particles, particle size of the core, and thickness of the shell

For the obtained substrate particles, a particle size distribution measuring device ("Multisizer 3" manufactured by Beckman Coulter Co., Ltd.) was used to measure the particle diameter of about 10,000 substrate particles. Determine the average particle size and standard deviation. The particle size was also measured by the same method for the core used in the production of the substrate particles. The thickness of the shell was determined from the difference between the particle diameter of the substrate particles and the particle diameter of the core.

(2) Compressive elastic modulus (10% K value and 30% K value) of the substrate particles, and 10% load value and 30% load value and 40% load value

The above-mentioned compression elastic modulus (10% K value and 30%) of the obtained substrate particles were obtained by the above method using a micro compression tester (Fischerscope H-100 manufactured by Fischer Co., Ltd.) at 23 ° C. The K value), and the 10% load value and the 30% load value and the 40% load value were measured.

(3) Compressive recovery rate of substrate particles

The compression recovery ratio of the obtained substrate particles was measured by the above method using a micro compression tester (Fischerscope H-100 manufactured by Fischer Co., Ltd.).

(4) Fracture strain of the substrate particles

The rupture strain was measured by the above method using a micro compression tester (Fischerscope H-100 manufactured by Fischer Co., Ltd.) under the conditions of 23 °C.

(5) Connection resistance

Production of the connection structure:

10 parts by weight of bisphenol A type epoxy resin ("Epikote 1009" manufactured by Mitsubishi Chemical Corporation), 40 parts by weight of acrylic rubber (weight average molecular weight: about 800,000), 200 parts by weight of methyl ethyl ketone, and microcapsule type hardening 50 parts by weight of the agent ("HX3941HP" manufactured by Asahi Kasei E-MATERIALS Co., Ltd.) and 2 parts by weight of a decane coupling agent ("SH6040" manufactured by Dow Corning Toray Silicon Co., Ltd.) were mixed, and conductive was added in such a manner that the content was 3% by weight. The particles are dispersed to obtain a resin composition.

The obtained resin composition was applied to a PET (polyethylene terephthalate) film having a thickness of 50 μm which was subjected to release treatment on one side, and dried by hot air at 70 ° C for 5 minutes. An anisotropic conductive film is used. The thickness of the anisotropic conductive film obtained was 12 μm.

The obtained anisotropic conductive film was cut into a size of 5 mm × 5 mm. The etched anisotropic conductive film was attached to an ITO (width: 3 cm, length: 3 cm) of an ITO electrode (having a height of 0.1 μm, L/S = 20 μm / 20 μm) provided with a surrounding wire for resistance measurement. The center of the electrode is approximately the center. Then, two flexible printed boards (width: 2 cm, length: 1 cm) provided with the same gold electrode were aligned so that the electrodes overlap each other, and then bonded. The laminate of the PET substrate and the two-layer flexible printed substrate was thermocompression bonded under pressure bonding conditions of 10 N, 180 ° C, and 20 seconds to obtain a bonded structure. Further, a two-layer flexible printed circuit board in which a copper electrode is formed on a polyimide film and Au is plated on the surface of the copper electrode is used.

Determination of connection resistance:

The connection resistance between the electrodes of the obtained connection structure was measured by a four-terminal method. The connection resistance was determined using the following criteria.

[Evaluation criteria for connection resistance]

○○: The connection resistance is 3.0 Ω or less

○: The connection resistance exceeds 3.0 Ω and is 4.0 Ω or less.

△: The connection resistance exceeds 4.0 Ω and is 5.0 Ω or less.

×: The connection resistance exceeds 5.0Ω

(6) Whether there is a crack in the electrode

In the connection structure obtained in the evaluation of the above (5) connection resistance, it was observed whether or not cracks occurred in 100 of the electrodes.

[The presence or absence of cracks in the electrode]

○○: Among the 100 electrodes, there is no crack-producing electrode

○: Among the 100 electrodes, the number of crack-producing electrodes is 2 or less.

△: Among the 100 electrodes, the number of cracked electrodes is 3 to 5

×: Among the 100 electrodes, the number of cracked electrodes is 6 to 10

××: Among the 100 electrodes, the number of cracked electrodes is 11 or more.

(7) Connection reliability under high temperature and high humidity conditions

100 pieces of the connection structure obtained in the evaluation of the above (5) connection resistance were placed in 85 ° C and 85% RH for 100 hours. In the 100 connected structures after the test, whether or not the conduction failure between the upper and lower electrodes occurred was evaluated.

○○: Among the 100 connected structures, the number of occurrences of conduction failure is one or less.

○: Among the 100 connected structures, the number of conduction failures is 2 to 5

△: Among the 100 connected structures, the number of conduction failures is 6 to 10

×: Among the 100 connected structures, the number of conduction failures is 11 or more.

The results are shown in Table 1 below. Further, the aspect ratios of the substrate particles obtained in Examples 1 to 3, 6, and 7 were all 1.2 or less. In addition, the evaluation results of the connection resistances in Examples 2 to 4 and 6 were all "○○", but the value of the connection resistance in Example 4 was lower than the values of the connection resistances in Examples 2 to 3 and 6. It can be considered to be affected by the protrusions.

Claims (11)

A substrate particle obtained by forming a conductive layer on a surface to obtain conductive particles having the conductive layer, and having a core and a core-shell particle disposed on a surface of the core, and 30% The compression recovery rate at the time of compression deformation is 50% or more, the compression elastic modulus at the compression of 10% is 3000 N/mm ² or more and less than 6000 N/mm ² , and the load value at 30% compression is relative to the load at 10% compression. The ratio of values is 3 or less. The substrate particle of claim 1, wherein the core is an organic core, and the shell is an inorganic shell. The substrate particle of claim 1, wherein the shell has a thickness of 100 nm or more and 5 μm or less. The substrate particle according to any one of claims 1 to 3, wherein the compression elastic modulus at 30% compression is 3000 N/mm ² or less. The substrate particles according to any one of claims 1 to 3, wherein a ratio of a load value at 40% compression to a load value at 10% compression is 6 or less. The substrate particle according to any one of claims 1 to 3, wherein the rupture strain is 10% or more and 30% or less. A conductive particle comprising: the substrate particle according to any one of claims 1 to 6; and a conductive layer disposed on a surface of the substrate particle. The conductive particle of claim 7, further comprising an insulating material disposed on a surface of the conductive layer. The conductive particle of claim 7 or 8, wherein the outer surface of the conductive layer has Protrusion. A conductive material comprising conductive particles and a binder resin, wherein the conductive particles comprise the substrate particles according to any one of claims 1 to 6 and a conductive layer disposed on a surface of the substrate particles. A connection structure including: a first connection target member having a first electrode on a surface thereof, a second connection target member having a second electrode on a surface thereof, and a connection between the first connection target member and the second connection target member The connection portion is formed of conductive particles or a conductive material containing the conductive particles and the binder resin, and the conductive particles are provided with the substrate particles according to any one of claims 1 to 6. And a conductive layer disposed on a surface of the substrate particle, wherein the first electrode and the second electrode are electrically connected to each other by the conductive particles.