TWI868135B - Resin particles, conductive particles, conductive materials and connection structures - Google Patents

Abstract

The present invention provides a resin particle that can effectively suppress aggregation, and when using a conductive particle having a conductive portion formed on the surface to electrically connect electrodes, the adhesion with the conductive portion can be effectively improved, thereby effectively reducing the connection resistance. Regarding the resin particle of the present invention, when a negative ion mass spectrum is obtained by time-of-flight secondary ion mass spectrometry for the outer surface of the resin particle, the ratio of the intensity of ^OH- ions to the total intensity of all negative ions is 2.0× ^10-2 or more.

Description

Resin particles, conductive particles, conductive materials and connection structures

The present invention relates to a resin particle having a polymer as a polymerizable component, and also to a conductive particle, a conductive material and a connection structure using the resin particle.

Anisotropic conductive materials such as anisotropic conductive pastes and anisotropic conductive films are widely known. In the anisotropic conductive materials, conductive particles are dispersed in a binder resin.

The anisotropic conductive material is used to electrically connect the electrodes of various connection target components such as flexible printed circuit boards (FPCs), glass substrates, glass epoxy substrates, and semiconductor chips to obtain a connection structure. In addition, as the conductive particles, conductive particles having substrate particles and a conductive layer disposed on the surface of the substrate particles are sometimes used. As the substrate particles, resin particles are sometimes used.

As an example of the conductive particles, metal-coated particles having synthetic resin particles and a metal film formed on the surface thereof are disclosed in the following patent document 1. In the metal-coated particles, the synthetic resin particles are composed of a copolymer obtained by polymerizing a monomer mixture containing a carboxyl group-containing monomer and a multifunctional monomer.

In addition, various adhesives are used to connect two components to be connected (adhered bodies). In order to make the thickness of the adhesive layer formed by the adhesive uniform and control the distance (gap) between the two components to be connected (adhered bodies), a gap material (spacer) is sometimes mixed in the adhesive. As the above-mentioned gap material (spacer), resin particles are sometimes used. [Prior technical literature] [Patent literature]

[Patent Document 1] Japanese Patent Publication No. 10-259253

[The problem the invention is trying to solve]

In recent years, when conductive materials or connecting materials containing conductive particles are used to electrically connect electrodes, it is expected that the electrodes can be electrically connected reliably even at a relatively low pressure, thereby reducing the connection resistance. For example, in the manufacturing method of a liquid crystal display device, when a flexible substrate is installed in the FOG (film on glass) method, an anisotropic conductive material is arranged on a glass substrate, and the flexible substrate is laminated and hot-pressed. In recent years, the narrow edge of liquid crystal panels and the thinness of glass substrates have been promoted. In this case, when installing the flexible substrate, if hot-pressing is performed at a higher pressure and a higher temperature, the flexible substrate may be deformed, resulting in uneven display. Therefore, when mounting a flexible substrate in the FOG method, it is expected that the heat pressing can be performed at a relatively low pressure. In addition, in addition to the FOG method, it is sometimes required to relatively reduce the pressure and temperature during the heat pressing.

When using conductive particles as conventional resin particles, if the electrodes are electrically connected at a relatively low pressure, the connection resistance may increase. The reasons for this may include: the conductive particles are not in sufficient contact with the electrodes (adherents), or the resin particles have low adhesion to the conductive parts disposed on the surfaces of the resin particles, or the conductive parts are broken or peeled off. In conventional resin particles, the improvement in adhesion between the resin particles and the conductive parts disposed on the surfaces of the resin particles is limited, and it is sometimes difficult to sufficiently improve the adhesion between the resin particles and the conductive parts disposed on the surfaces of the resin particles.

In addition, when the conductive part (coating layer) is formed by coating with conventional resin particles, the resin particles may aggregate with each other and coating may not be performed well. As a result, the particle size of the conductive particles is uneven, or the thickness of the conductive part in the conductive particles is uneven, and the conductive particles do not uniformly contact the electrode, resulting in increased connection resistance.

Furthermore, when conventional resin particles are used as a gap material (spacer), it is difficult to maintain a good dispersion state, and the resin particles aggregate with each other. Furthermore, in conventional resin particles, there are cases where the resin particles do not sufficiently contact with the connecting object member (adherent body) and a sufficient gap control effect cannot be obtained.

The purpose of the present invention is to provide a resin particle that can effectively inhibit agglomeration, and when using conductive particles having a conductive portion formed on the surface to electrically connect electrodes, it can effectively improve the adhesion with the conductive portion, and further, can effectively reduce the connection resistance. In addition, the purpose of the present invention is to provide a conductive particle, a conductive material and a connection structure using the above-mentioned resin particles. [Technical means for solving the problem]

According to a broad aspect of the present invention, there is provided a resin particle wherein, for the outer surface of the resin particle, when a negative ion mass spectrum is obtained by time-of-flight secondary ion mass spectrometry, the ratio of the intensity of ^OH- ions to the total intensity of all negative ions is 2.0× ^10-2 or more.

In a certain specific form of the resin particles of the present invention, the compressive elastic modulus when compressed by 10% is not less than 500 N/mm ² and not more than 4500 N/mm ² .

In a certain specific form of the resin particles of the present invention, the compressive elastic modulus when compressed by 30% is greater than 300 N/mm ² and less than 4000 N/mm ² .

In a specific embodiment of the resin particles of the present invention, the resin particles are polymers comprising polymerizable components of a plurality of polymerizable compounds.

In a specific form of the resin particle of the present invention, the polymerizable component constituting the polymer includes a crosslinking compound, and the content of the crosslinking compound is 30% by weight or more in 100% by weight of the polymerizable component.

In a certain specific form of the resin particles of the present invention, the above-mentioned polymerizable components constituting the above-mentioned polymer include a cross-linking compound and a polymerizable compound having a polar functional group, and the content of the above-mentioned cross-linking compound in 100% by weight of the above-mentioned polymerizable components is less than 30% by weight, and the content of the above-mentioned polymerizable compound having a polar functional group in 100% by weight of the above-mentioned polymerizable components is greater than 0.5% by weight and less than 30% by weight.

In a specific form of the resin particle of the present invention, the polymerizable compound having a polar functional group includes a polymerizable compound having a hydroxyl group, a polymerizable compound having a carboxyl group, or a polymerizable compound having a phosphate group.

In a specific form of the resin particles of the present invention, the crosslinking compound includes divinylbenzene, tetramethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, glycerol di(meth)acrylate, or 2-(meth)acryloyloxyethyl acid phosphate.

In a specific embodiment of the resin particle of the present invention, the resin particle is used as a spacer, or is used to obtain a conductive particle having the conductive portion by forming the conductive portion on the surface.

According to a broad aspect of the present invention, there is provided a conductive particle comprising the above-mentioned resin particle and a conductive portion disposed on a surface of the resin particle.

In a specific form of the conductive particle of the present invention, the conductive particle further comprises an insulating material disposed on the outer surface of the conductive portion.

In a specific embodiment of the conductive particle of the present invention, the conductive particle has protrusions on the outer surface of the conductive portion.

According to a broad aspect of the present invention, a conductive material is provided, which includes conductive particles and a binder resin, wherein the conductive particles include the resin particles and a conductive portion disposed on a surface of the resin particles.

According to a broad form of the present invention, a connection structure is provided, which comprises: a first connection target component having a first electrode on its surface, a second connection target component having a second electrode on its surface, and a connection portion connecting the first connection target component and the second connection target component, wherein the connection portion is formed by conductive particles, or is formed by the conductive material comprising conductive particles and a binder resin, wherein the conductive particles have the resin particles and a conductive portion disposed on the surface of the resin particles, and the first electrode and the second electrode are electrically connected via the conductive particles. [Effect of the Invention]

In the resin particles of the present invention, when the negative ion mass spectrum is obtained by time-of-flight secondary ion mass spectrometry, the ratio of the intensity of ^OH- ions to the total intensity of all negative ions is 2.0× ^10-2 or more. Since the resin particles of the present invention have the above-mentioned structure, aggregation can be effectively suppressed. When the conductive particles having a conductive part formed on the surface are used to electrically connect electrodes, the adhesion with the conductive part can be effectively improved, and the connection resistance can be effectively reduced.

The following is a detailed description of the present invention.

(Resin particles) Regarding the resin particles of the present invention, when a negative ion mass spectrum is obtained by time-of-flight secondary ion mass spectrometry, the ratio of the intensity of OH ^- ions to the total intensity of all negative ions on the outer surface of the resin particles is 2.0×10 ^-2 or more.

Since the resin particles of the present invention have the above-mentioned structure, aggregation can be effectively suppressed. When the conductive particles having a conductive part formed on the surface are used to electrically connect electrodes, the adhesion with the conductive part can be effectively improved, and further, the connection resistance can be effectively reduced.

Regarding the resin particles of the present invention, since the intensity of OH ^- ions satisfies a specific relationship when a negative ion mass spectrum is obtained by time-of-flight secondary ion mass spectrometry, a relatively large number of hydroxyl groups can be arranged on the outer surface of the resin particles. If hydroxyl groups are arranged on the outer surface of the resin particles, the adhesion between the resin particles and the conductive part can be improved by the interaction with the hydroxyl groups, thereby effectively suppressing the occurrence of cracking or peeling of the conductive part. In addition, in the conductive particles using the resin particles of the present invention, the connection resistance between the electrodes can be effectively reduced, thereby effectively improving the connection reliability between the electrodes. For example, even if a connection structure in which electrodes are electrically connected by using the conductive particles of the resin particles of the present invention is placed under high temperature and high humidity conditions for a long time, the connection resistance is unlikely to become higher, and thus poor conduction is less likely to occur.

Furthermore, in the resin particles of the present invention, the aggregation of the resin particles can be effectively suppressed. As a result, when the resin particles of the present invention are used as a gap material (spacer), the dispersion state can be well maintained, so that the particle size of the spacer can be made uniform. Furthermore, it can fully contact with the connecting object components, so that a sufficient gap control effect can be obtained.

Regarding the resin particles of the present invention, when a negative ion mass spectrum is obtained by time-of-flight secondary ion mass spectrometry (TOF-SIMS) on the outer surface of the resin particles, the ratio of the intensity of ^OH- ions to the total intensities of all negative ions (intensity of ^OH- ions/total intensities of all negative ions) is 2.0× ^10-2 or more.

In the TOF-SIMS measurement, the outer surface of the resin particles is sputtered twice, and the ratio (OH ^- ion intensity/total of all negative ion intensities) is measured using TOF-SIMS. The measurement is performed in a dispersed state such that 40 to 60 resin particles are arranged in an area of 500 μm×500 μm, and the average value of the ratio (OH ^- ion intensity/total of all negative ion intensities) when the cumulative number of detections reaches 50 is used. In addition, when it is difficult to arrange 40 to 60 resin particles in an area of 500 μm×500 μm due to the size of the resin particles, the measurement can be performed after appropriately reducing the number of arranged particles. In the above measurement, for example, a measurement result of a thickness region of about 2 nm from the outer surface of the above resin particle toward the inner side is obtained. In addition, in the above measurement, it is preferred to calculate the above ratio by taking the arithmetic average of the ratio (OH ^- ion intensity/total of all negative ion intensities) of three randomly selected resin particles.

The above ratio (OH ^- ion strength/total strength of all negative ions) is preferably greater than 2.5× ^10-2 , and more preferably greater than 3.0× ^10-2 . There is no particular upper limit to the above ratio (OH ^- ion strength/total strength of all negative ions). The above ratio (OH ^- ion strength/total strength of all negative ions) may be less than 9.0× ^10-2 . If the above-mentioned resin particles satisfy the above-mentioned preferred morphology, aggregation can be further effectively suppressed. Furthermore, if the above-mentioned resin particles satisfy the above-mentioned preferred morphology, when the electrodes are electrically connected using conductive particles having a conductive portion formed on the surface, the adhesion with the conductive portion can be further effectively improved, and further, the connection resistance can be further effectively reduced.

The TOF-SIMS described above uses the "TOF-SIMS 5" manufactured by ION TOF. In order to measure the OH ^- ion intensity and total ion intensity on the outer surface of the resin particles using the TOF-SIMS analysis device, for example, a Bi ³⁺ ion gun is used as the primary ion source for measurement, and the measurement is performed under the condition of 25 keV. Sputtering is a method of introducing an inert gas such as argon into a vacuum, applying a negative voltage to the target to generate a flash discharge, ionizing the inert gas atoms, and causing the gas particles to collide with the surface of the target at high speed and hit the surface strongly. The surface of the target can be ground at a depth of nanometers to micrometers. Specifically, for example, by using O ₂ ⁺ for sputtering, the surface of the resin particle can be excavated at a depth of about 1 nm/time. The ratio of the ^OH- ion intensity to the total ion intensity in a region about 2 nm thick from the outer surface of the resin particle to the inner side can be measured by performing sputtering twice and using TOF-SIMS.

The compressive elastic modulus (10% K value) when the resin particles are compressed by 10% is preferably 500 N/mm ² or more, more preferably 1000 N/mm ² or more, and preferably 6000 N/mm ² or less, more preferably 5000 N/mm ² or less, further preferably 4500 N/mm ² or less, and particularly preferably 3500 N/mm ² or less. If the 10% K value is above the lower limit and below the upper limit, agglomeration can be further effectively suppressed. Furthermore, if the 10% K value is above the lower limit and below the upper limit, when the conductive particles having a conductive portion formed on the surface are used to electrically connect the electrodes, the adhesion with the conductive portion can be further effectively improved, and further, the connection resistance can be further effectively reduced.

The compressive elastic modulus (30% K value) when the resin particles are compressed by 30% is preferably 300 N/mm ² or more, more preferably 500 N/mm ² or more, and preferably 5500 N/mm ² or less, more preferably 4500 N/mm ² or less, further preferably 4000 N/mm ² or less, and particularly preferably 3000 N/mm ² or less. If the 30% K value is above the lower limit and below the upper limit, agglomeration can be further effectively suppressed. Furthermore, if the 30% K value is above the lower limit and below the upper limit, when the conductive particles having a conductive portion formed on the surface are used to electrically connect the electrodes, the adhesion with the conductive portion can be further effectively improved, and further, the connection resistance can be further effectively reduced.

The compressive elastic modulus (10% K value and 30% K value) of the resin particles can be measured as follows.

Using a micro compression tester, compress one resin particle at 25°C, compression speed 0.3 mN/sec, and maximum test load 20 mN on the smooth end face of a cylinder (diameter 50 μm, made of diamond). Measure the load value (N) and compression displacement (mm) at this time. The above-mentioned compressive elastic modulus (10% K value or 30% K value) can be calculated by the following formula based on the obtained measured values. As the above-mentioned micro compression tester, for example, "Fischerscope H-100" manufactured by Fischer Company can be used. The compressive elastic modulus (10% K value or 30% K value) of the resin particles is preferably calculated by arithmetically averaging the compressive elastic modulus (10% K value or 30% K value) of 50 randomly selected resin particles.

10%K value or 30%K value (N/ ^mm2 ) = (3/2 ^1/2 )・F・S ^-3/2・R ^-1/2 F: Load value when the resin particle is compressed and deformed by 10% or 30% (N) S: Compression displacement when the resin particle is compressed and deformed by 10% or 30% (mm) R: Radius of the resin particle (mm)

The above-mentioned compressive elastic modulus generally and quantitatively indicates the hardness of the resin particles. By using the above-mentioned compressive elastic modulus, the hardness of the resin particles can be quantitatively and uniformly indicated.

The compression recovery rate of the resin particles is preferably 5% or more, more preferably 10% or more, and preferably 60% or less, more preferably 45% or less. If the compression recovery rate is above the lower limit and below the upper limit, aggregation can be further effectively suppressed. Furthermore, when the compression recovery rate is above the lower limit and below the upper limit, when the conductive particles having a conductive part formed on the surface are used to electrically connect the electrodes, the adhesion with the conductive part can be further effectively improved, and further, the connection resistance can be further effectively reduced.

The compression recovery rate of the resin particles can be measured as follows.

Spread the resin particles on the test stand. For one of the scattered resin particles, use a micro compression tester to apply a load (reverse load value) to the smooth pressure head end of a cylinder (diameter 50 μm, made of diamond) at 25°C in the center direction of the resin particle until the resin particle is compressively deformed by 30%. Thereafter, unload until the load value used for the origin (0.40 mN) is reached. The load-compression displacement during this period is measured, and the compression recovery rate can be calculated according to the following formula. In addition, the load speed is set to 0.33 mN/second. As the above-mentioned micro compression tester, for example, the "Fischerscope H-100" manufactured by Fischer Company can be used.

Compression recovery rate (%) = [L2/L1] × 100  L1: Compression displacement from the original load value to the reverse load value when the load is applied  L2: Unloading displacement from the reverse load value to the original load value when the load is released

The use of the above-mentioned resin particles is not particularly limited. The above-mentioned resin particles can be preferably used for various purposes. The above-mentioned resin particles are preferably used as spacers, or used to obtain conductive particles having the above-mentioned conductive parts by forming a conductive part on the surface. In the above-mentioned conductive particles, the above-mentioned conductive part is formed on the surface of the above-mentioned resin particles. The above-mentioned resin particles are preferably used to obtain conductive particles having the above-mentioned conductive parts by forming a conductive part on the surface. The above-mentioned conductive particles are preferably used to electrically connect electrodes. The above-mentioned conductive particles can also be used as gap materials (spacers). The above-mentioned resin particles are preferably used as gap materials (spacers). As the usage of the above-mentioned gap material (spacer), there can be listed spacers for liquid crystal display elements, spacers for gap control, and spacers for stress relief, etc. The above-mentioned gap control spacer can be used to control the gap of laminated chips or electronic component devices to ensure the height and flatness of the bracket, and to control the gap of optical components to ensure the smoothness of the glass surface and the thickness of the adhesive layer, etc. The above-mentioned stress relief spacer can be used to relieve the stress of sensing chips, etc., and to relieve the stress of the connection part connecting two connection object components, etc. In addition, when the above-mentioned resin particles are used as gap materials (spacers), the dispersion state can be well maintained, so that the particle size of the spacer can be uniform. Furthermore, it can fully contact with the connected component, thereby achieving a sufficient gap control effect.

The resin particles are preferably used as spacers for liquid crystal display elements, and are preferably used as peripheral sealants for liquid crystal display elements. In the peripheral sealants for liquid crystal display elements, the resin particles are preferably used as spacers. Since the resin particles have good compression deformation characteristics and good compression failure characteristics, when the resin particles are used as spacers and arranged between substrates, or when the conductive part is formed on the surface and used as conductive particles to electrically connect electrodes, the spacers or conductive particles are efficiently arranged between substrates or between electrodes. Furthermore, since the resin particles can suppress damage to components for liquid crystal display elements, etc., poor connection and poor display are less likely to occur in a liquid crystal display element using the liquid crystal display element spacer and a connection structure using the conductive particles.

Furthermore, the resin particles can also be preferably used as inorganic fillers, color enhancer additives, shock absorbers or vibration absorbers. For example, the resin particles can be used as a substitute for rubber or springs.

The following describes other details of the resin particles.

(Other details of the resin particles) The above-mentioned resin particles are preferably polymers comprising polymerizable components of a plurality of polymerizable compounds. In the above-mentioned resin particles, it is preferred that the central portion of the resin particle and the surface portion of the resin particle are composed of the same above-mentioned polymerizable components. The blending ratio of the polymerizable components in the central portion of the above-mentioned resin particle and the blending ratio of the polymerizable components in the surface portion of the above-mentioned resin particle may be the same or different. The constituent ratio of the constituent components in the central portion of the above-mentioned resin particle and the constituent ratio of the constituent components in the surface portion of the above-mentioned resin particle may be the same or different. If the above-mentioned resin particles satisfy the above-mentioned preferred morphology, aggregation can be further effectively inhibited. Furthermore, if the resin particles satisfy the above-mentioned preferred morphology, when the conductive particles having a conductive portion formed on the surface are used to electrically connect electrodes, the adhesion with the conductive portion can be further effectively improved, and further, the connection resistance can be further effectively reduced.

In the above-mentioned resin particles, it is preferred that the central portion of the resin particles is formed by the central portion forming material, and the surface portion of the resin particles is formed by the surface portion forming material. In the above-mentioned resin particles, it is preferred that the composition of the above-mentioned central portion forming material is the same as the composition of the above-mentioned surface portion forming material. In the above-mentioned resin particles, the composition ratio of the above-mentioned central portion forming material and the composition ratio of the above-mentioned surface portion forming material may be the same or different. Furthermore, in the above-mentioned resin particles, it is preferred that there is a region including both the above-mentioned central portion forming material and the above-mentioned surface portion forming material. In the above-mentioned resin particles, it is preferred that the resin particles have a region in the central portion, which includes the above-mentioned central portion forming material and does not include the above-mentioned surface portion forming material or includes less than 25 weight % of the above-mentioned surface portion forming material. In the resin particles, it is preferred that the resin particles have a region on the surface, which region includes the surface forming material and does not include the center forming material or includes less than 25% by weight of the center forming material. If the resin particles satisfy the preferred morphology, aggregation can be further effectively suppressed. Furthermore, if the resin particles satisfy the preferred morphology, when the electrodes are electrically connected using conductive particles having a conductive portion formed on the surface, the adhesion with the conductive portion can be further effectively improved, and further, the connection resistance can be further effectively reduced.

The resin particles are preferably core-shell particles that do not have a core and a shell disposed on the surface of the core, and preferably do not have an interface between the core and the shell in the resin particles. The resin particles are preferably free of interfaces in the resin particles, and more preferably do not have interfaces where different surfaces are in contact with each other. The resin particles are preferably free of discontinuous portions on the surface, and preferably free of discontinuous portions on the structural surface. If the resin particles satisfy the above preferred morphology, aggregation can be further effectively suppressed. Furthermore, if the resin particles satisfy the above-mentioned preferred morphology, when the conductive particles having a conductive portion formed on the surface are used to electrically connect electrodes, the adhesion with the conductive portion can be further effectively improved, and further, the connection resistance can be further effectively reduced.

In the resin particles, it is preferred that the polymerizable components constituting the polymer include a crosslinking compound. When the polymerizable components constituting the polymer include a crosslinking compound, the content of the crosslinking compound in 100% by weight of the polymerizable components is preferably 30% by weight or more, more preferably 40% by weight or more. The upper limit of the content of the crosslinking compound is not particularly limited. The content of the crosslinking compound is preferably 80% by weight or less, more preferably 70% by weight or less, and further preferably 60% by weight or less. If the resin particles satisfy the preferred morphology, aggregation can be further effectively suppressed. Furthermore, if the resin particles satisfy the above-mentioned preferred morphology, when the conductive particles having a conductive portion formed on the surface are used to electrically connect electrodes, the adhesion with the conductive portion can be further effectively improved, and further, the connection resistance can be further effectively reduced.

In the resin particles, the polymerizable components constituting the polymer may be any one of a polymerizable component including a crosslinking compound without a polar functional group and not including a crosslinking compound with a polar functional group, and a polymerizable component including a crosslinking compound without a polar functional group and a crosslinking compound with a polar functional group. In the resin particles, the polymerizable components constituting the polymer may also be a polymerizable component including a crosslinking compound without a polar functional group and not including a crosslinking compound with a polar functional group. In the resin particles, the polymerizable components constituting the polymer may also be a polymerizable component including a crosslinking compound without a polar functional group and a crosslinking compound with a polar functional group.

When the polymerizable components constituting the polymer include a crosslinking compound without a polar functional group and do not include a crosslinking compound with a polar functional group, the content of the crosslinking compound without a polar functional group in 100% by weight of the polymerizable components is preferably 30% by weight or more, more preferably 40% by weight or more. The upper limit of the content of the crosslinking compound without a polar functional group is not particularly limited. The content of the crosslinking compound without a polar functional group is preferably 80% by weight or less, more preferably 70% by weight or less, and further preferably 60% by weight or less. If the resin particles satisfy the preferred morphology, aggregation can be further effectively inhibited. Furthermore, if the resin particles satisfy the above-mentioned preferred morphology, when the conductive particles having a conductive portion formed on the surface are used to electrically connect electrodes, the adhesion with the conductive portion can be further effectively improved, and further, the connection resistance can be further effectively reduced.

When the polymerizable components constituting the polymer include a crosslinking compound without a polar functional group and a crosslinking compound with a polar functional group, the total content of the crosslinking compound without a polar functional group and the crosslinking compound with a polar functional group in 100% by weight of the polymerizable components is preferably 30% by weight or more, and more preferably 40% by weight or more. The upper limit of the total content of the crosslinking compound without a polar functional group and the crosslinking compound with a polar functional group is not particularly limited. The total content of the crosslinking compound without a polar functional group and the crosslinking compound with a polar functional group is preferably 80% by weight or less, more preferably 70% by weight or less , and further preferably 60% by weight or less. If the resin particles satisfy the above-mentioned preferred morphology, aggregation can be further effectively inhibited. Furthermore, if the resin particles satisfy the above-mentioned preferred morphology, when the conductive particles having a conductive portion formed on the surface are used to electrically connect electrodes, the adhesion with the conductive portion can be further effectively improved, and further, the connection resistance can be further effectively reduced.

In the resin particles, the polymerizable components constituting the polymer preferably include a crosslinking compound and a polymerizable compound having a polar functional group. In the case where the polymerizable components constituting the polymer include a crosslinking compound and a polymerizable compound having a polar functional group, the content of the crosslinking compound in 100% by weight of the polymerizable components is preferably less than 30% by weight, and more preferably less than 20% by weight. The lower limit of the content of the crosslinking compound is not particularly limited. The content of the crosslinking compound may also be 5% by weight or more. In the case where the polymerizable components constituting the polymer include a crosslinking compound and a polymerizable compound having a polar functional group, the content of the polymerizable compound having a polar functional group in 100% by weight of the polymerizable components is preferably 0.5% by weight or more, more preferably 2% by weight or more, and preferably less than 30% by weight, and more preferably less than 20% by weight. If the resin particles satisfy the above-mentioned preferred morphology, aggregation can be further effectively suppressed. In addition, if the resin particles satisfy the above-mentioned preferred morphology, when the conductive particles having a conductive part formed on the surface are used to electrically connect electrodes, the adhesion with the conductive part can be further effectively improved, and further, the connection resistance can be further effectively reduced.

In the resin particles, the polymerizable components constituting the polymer preferably include a crosslinking compound without a polar functional group and a polymerizable compound without a crosslinking property and having a polar functional group. In the case where the polymerizable components constituting the polymer include a crosslinking compound without a polar functional group and a polymerizable compound without a crosslinking property and having a polar functional group, the content of the crosslinking compound without a polar functional group in 100% by weight of the polymerizable components is preferably less than 30% by weight, and more preferably less than 20% by weight. The lower limit of the content of the crosslinking compound without a polar functional group is not particularly limited. The content of the crosslinking compound without a polar functional group may also be 5% by weight or more. In the case where the above-mentioned polymerizable components constituting the above-mentioned polymer include a cross-linking compound without a polar functional group and a polymerizable compound without a cross-linking property and having a polar functional group, the content of the above-mentioned polymerizable compound without a cross-linking property and having a polar functional group in 100% by weight of the above-mentioned polymerizable components is preferably 0.5% by weight or more, more preferably 2% by weight or more, and preferably 30% by weight or less, more preferably 20% by weight or less. If the above-mentioned resin particles satisfy the above-mentioned preferred morphology, aggregation can be further effectively suppressed. In addition, if the above-mentioned resin particles satisfy the above-mentioned preferred morphology, when the electrodes are electrically connected using conductive particles having a conductive portion formed on the surface, the adhesion with the conductive portion can be further effectively improved, and further, the connection resistance can be further effectively reduced.

Furthermore, from the viewpoint that it is easier to set the ratio of the intensity of ^OH- ions to the total intensity of all negative ions to 2.0× ^10-2 or more when a negative ion mass spectrum is obtained by time-of-flight secondary ion mass spectrometry on the outer surface of the above-mentioned resin particles, the above-mentioned resin particles preferably satisfy any of the following relationships. 1) The above-mentioned polymerizable components constituting the above-mentioned polymer include a crosslinking compound, and the content of the above-mentioned crosslinking compound in 100% by weight of the above-mentioned polymerizable components is 30% by weight or more. 2) The above-mentioned polymerizable components constituting the above-mentioned polymer include a crosslinking compound and a polymerizable compound having a polar functional group, and the content of the above-mentioned crosslinking compound in 100% by weight of the above-mentioned polymerizable components is less than 30% by weight, and the content of the above-mentioned polymerizable compound having a polar functional group is 0.5% by weight or more and 30% by weight or less.

In particular, in the above 1), if the content of the crosslinking compound is 30 wt% or more and 80 wt% or less, it is easier to set the ratio of the strength of ^OH- ions to the total strength of all negative ions to 2.0× ^10-2 or more.

The polymerizable compound having a polar functional group is not particularly limited. The polar functional group is not particularly limited. Examples of the polar functional group include a hydroxyl group, a carboxyl group, a sulfonic acid group, and a phosphoric acid group. The polymerizable compound having a polar functional group may be used alone or in combination of two or more.

Examples of polymerizable compounds having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, glycerol di(meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl (meth)acrylate, pentaerythritol tri(meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, and polyethylene glycol (meth)acrylate.

Examples of the polymerizable compound having a carboxyl group include (meth)acrylic acid, 2-carboxyethyl (meth)acrylate, and 2-(meth)acryloyloxyethyl succinate.

Examples of the polymerizable compound having a sulfonic acid group include 3-sulfopropyl (meth)acrylate and the like.

As the polymerizable compound having a phosphoric acid group, 2-(meth)acryloyloxyethyl acid phosphate and the like can be cited.

In the above-mentioned resin particles, the above-mentioned polymerizable compound having a polar functional group preferably includes a polymerizable compound having a hydroxyl group, a polymerizable compound having a carboxyl group, or a polymerizable compound having a phosphate group. In the above-mentioned resin particles, the above-mentioned polymerizable compound having a polar functional group more preferably includes 2-hydroxypropyl (meth)acrylate, (meth)acrylic acid, 2-(meth)acryloyloxyethyl succinate, or 2-(meth)acryloyloxyethyl acid phosphate. In the above-mentioned resin particles, the above-mentioned polymerizable compound having a polar functional group further preferably includes (meth)acrylic acid, 2-(meth)acryloyloxyethyl succinate, or 2-(meth)acryloyloxyethyl acid phosphate. If the above-mentioned resin particles satisfy the above-mentioned preferred morphology, aggregation can be further effectively suppressed. Furthermore, if the resin particles satisfy the above-mentioned preferred morphology, when the conductive particles having a conductive portion formed on the surface are used to electrically connect electrodes, the adhesion with the conductive portion can be further effectively improved, and further, the connection resistance can be further effectively reduced.

The crosslinking compound is not particularly limited. Examples of the crosslinking compound include divinylbenzene, (di/tri/tetra)methylene glycol (meth)acrylate, (di/tri/tetra)ethylene glycol (meth)acrylate, polytetramethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol (meth)acrylate, 1,9-nonanediol (meth)acrylate, dihydroxymethyltricyclodecane dimethacrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, glycerol di(meth)acrylate, and 2-(meth)acryloyloxyethyl acid phosphate ("LIGHT ESTER P-2M" manufactured by Kyoeisha Chemical Co., Ltd.). The crosslinking compound may be used alone or in combination of two or more.

In the resin particles, the crosslinking compound preferably includes the following compounds. Examples of the compound include divinylbenzene, tetramethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, glycerol di(meth)acrylate, and 2-(meth)acryloyloxyethyl acid phosphate ("LIGHT ESTER P-2M" manufactured by Kyoeisha Chemical Co., Ltd.). In the resin particles, the crosslinking compound more preferably includes glycerol di(meth)acrylate, 2-(meth)acryloyloxyethyl acid phosphate ("LIGHT ESTER P-2M" manufactured by Kyoeisha Chemical Co., Ltd.), or pentaerythritol tri(meth)acrylate. If the resin particles satisfy the preferred morphology, aggregation can be further effectively suppressed. Furthermore, if the resin particles satisfy the above-mentioned preferred morphology, when the conductive particles having a conductive portion formed on the surface are used to electrically connect electrodes, the adhesion with the conductive portion can be further effectively improved, and further, the connection resistance can be further effectively reduced.

The above-mentioned polymerizable compound having a polar functional group may also be a crosslinking compound. The above-mentioned crosslinking compound may also be a polymerizable compound having a polar functional group. When the above-mentioned polymerizable component includes a compound having crosslinking property, a polar functional group and polymerizability, the above-mentioned polymerizable compound includes both a crosslinking compound and a polymerizable compound having a polar functional group. The content of the above-mentioned crosslinking compound includes the content of the above-mentioned compound having crosslinking property, a polar functional group and polymerizability. The content of the above-mentioned polymerizable compound having a polar functional group includes the content of the above-mentioned compound having crosslinking property, a polar functional group and polymerizability.

In the resin particles, the polymerizable components constituting the polymer may or may not contain a non-crosslinking compound. In the resin particles, the polymerizable components constituting the polymer may not contain a non-crosslinking compound. In the resin particles, the polymerizable components constituting the polymer may also contain a non-crosslinking compound. The non-crosslinking compound may be a non-crosslinking compound without a polar functional group. The non-crosslinking compound may be used alone or in combination of two or more.

As the non-crosslinking compound, there can be listed: styrene monomers such as styrene, α-methylstyrene, and chlorostyrene as vinyl compounds; vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; vinyl acetate, vinyl butyrate, vinyl laurate, and vinyl stearate acid vinyl ester compounds; halogen-containing monomers such as vinyl chloride and vinyl fluoride; methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, and (meth)acrylate as (meth)acrylic acid compounds. Alkyl (meth)acrylate compounds such as stearyl, cyclohexyl (meth)acrylate, isobutyl (meth)acrylate; (meth)acrylate compounds containing oxygen atoms such as 2-hydroxyethyl (meth)acrylate, glycerol (meth)acrylate, polyoxyethylene (meth)acrylate, glycidyl (meth)acrylate; nitrile-containing monomers such as (meth)acrylonitrile; halogen-containing (meth)acrylate compounds such as trifluoromethyl (meth)acrylate and pentafluoroethyl (meth)acrylate; olefin compounds such as diisobutylene, isobutylene, linealene, ethylene, propylene as α-olefin compounds; isoprene, butadiene, etc. as conjugated diene compounds.

When the polymerizable component constituting the polymer includes the non-crosslinking compound, the content of the non-crosslinking compound in 100% by weight of the polymerizable component may be 1% by weight or more, 5% by weight or more, 10% by weight or more, 20% by weight or more, 30% by weight or more, or 40% by weight or more. When the polymerizable component constituting the polymer includes the non-crosslinking compound, the content of the non-crosslinking compound in 100% by weight of the polymerizable component may be 90% by weight or less, 80% by weight or less, 70% by weight or less, 60% by weight or less, or 50% by weight or less.

The particle size of the resin particles can be appropriately set according to the purpose. The particle size of the resin particles is preferably 0.5 μm or more, more preferably 1 μm or more, and preferably 500 μm or less, more preferably 300 μm or less, further preferably 100 μm or less, further preferably 50 μm or less, and particularly preferably 30 μm or less. If the particle size of the resin particles is above the lower limit and below the upper limit, the resin particles can be more suitably used for conductive particles or spacers. If the particle size of the resin particles is 0.5 μm or more and 500 μm or less, the resin particles can be suitably used for conductive particles. If the particle size of the resin particles is 0.5 μm or more and 500 μm or less, the resin particles can be suitably used as a spacer.

The particle size of the resin particles is preferably an average particle size, and more preferably a number average particle size. The particle size of the resin particles is obtained by observing 50 random resin particles using an electron microscope or an optical microscope and calculating the average particle size of each resin particle, or by using a particle size distribution measuring device. In the observation using an electron microscope or an optical microscope, the particle size of each resin particle is obtained as the particle size measured in terms of a circle equivalent diameter. In the observation using an electron microscope or an optical microscope, the average particle size measured in terms of a circle equivalent diameter of 50 random resin particles is almost equal to the average particle size measured in terms of a sphere equivalent diameter. In the particle size distribution measuring device, the particle size of each resin particle is determined as the particle size measured in terms of spherical equivalent diameter. The average particle size of the resin particles is preferably calculated by the particle size distribution measuring device.

When the particle size of the resin particles among the conductive particles is measured, the measurement can be performed, for example, in the following manner.

Conductive particles were added to "Technovit 4000" manufactured by Kulzer in a content of 30% by weight and dispersed to prepare an embedded resin body for conductive particle inspection. An ion milling device ("IM4000" manufactured by Hitachi High-Technologies Corporation) was used to cut out a cross section of the conductive particles dispersed in the embedded resin body for inspection near the center. Then, using a field emission scanning electron microscope (FE-SEM), the image magnification was set to 25,000 times, 50 conductive particles were randomly selected, and the resin particles of each conductive particle were observed. The particle size of the resin particles in each conductive particle was measured, and after taking the arithmetic average, the obtained value was set as the particle size of the resin particle.

The coefficient of variation (CV value) of the particle size of the resin particles is preferably 10% or less, and more preferably 7% or less. If the coefficient of variation of the particle size of the resin particles is below the upper limit, the resin particles can be more preferably used for spacers and conductive particles.

The above-mentioned coefficient of variation (CV value) can be measured as follows.

CV value (%) = (ρ/Dn) × 100 ρ: Standard deviation of the particle size of the resin particles Dn: Average value of the particle size of the resin particles

The shape of the resin particles is not particularly limited. The resin particles may be spherical, other than spherical, or flat.

(Conductive particles) The conductive particles include the resin particles and a conductive portion arranged on the surface of the resin particles.

FIG1 is a cross-sectional view showing a conductive particle according to a first embodiment of the present invention.

The conductive particle 1 shown in FIG1 has a resin particle 11 and a conductive portion 2 disposed on the surface of the resin particle 11. The conductive portion 2 is in contact with the surface of the resin particle 11. The conductive portion 2 covers the surface of the resin particle 11. The conductive particle 1 is a coated particle in which the surface of the resin particle 11 is coated with the conductive portion 2. In the conductive particle 1, the conductive portion 2 is a single-layer conductive portion (conductive layer).

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

The conductive particle 21 shown in Fig. 2 has a resin particle 11 and a conductive portion 22 disposed on the surface of the resin particle 11. The conductive portion 22 generally has a first conductive portion 22A on the resin particle 11 side and a second conductive portion 22B on the side opposite to the resin particle 11 side.

The conductive particle 1 shown in FIG1 and the conductive particle 21 shown in FIG2 differ only in the conductive portion 22. That is, the conductive particle 1 has a single-layered conductive portion, whereas the conductive particle 21 has a double-layered first conductive portion 22A and a second conductive portion 22B. The first conductive portion 22A and the second conductive portion 22B may be different conductive portions or may be the same conductive portion.

The first conductive portion 22A is disposed on the surface of the resin particle 11. The first conductive portion 22A is disposed between the resin particle 11 and the second conductive portion 22B. The first conductive portion 22A is in contact with the resin particle 11. The second conductive portion 22B is in contact with the first conductive portion 22A. The first conductive portion 22A is disposed on the surface of the resin particle 11, and the second conductive portion 22B is disposed on the surface of the first conductive portion 22A.

FIG3 is a cross-sectional view showing a conductive particle according to a third embodiment of the present invention.

The conductive particle 31 shown in FIG3 has a resin particle 11, a conductive portion 32, a plurality of core materials 33, and a plurality of insulating materials 34. The conductive portion 32 is disposed on the surface of the resin particle 11. The plurality of core materials 33 are disposed on the surface of the resin particle 11. The conductive portion 32 is disposed on the surface of the resin particle 11 in a manner covering the resin particle 11 and the plurality of core materials 33. In the conductive particle 31, the conductive portion 32 is a single-layer conductive portion (conductive layer).

The conductive particle 31 has a plurality of protrusions 31a on the outer surface. In the conductive particle 31, the conductive part 32 has a plurality of protrusions 32a on the outer surface. The plurality of core materials 33 can make the outer surface of the conductive part 32 bulge. The outer surface of the conductive part 32 bulges due to the plurality of core materials 33, thereby forming the protrusions 31a and 32a. The plurality of core materials 33 are embedded in the conductive part 32. The core material 33 is arranged on the inner side of the protrusions 31a and 32a. In the conductive particle 31, a plurality of core materials 33 are used to form the protrusions 31a and 32a. In the conductive particle, the protrusions may not be formed using a plurality of the core materials. The conductive particle may not have a plurality of the core materials.

The conductive particles 31 have an insulating substance 34 disposed on the outer surface of the conductive portion 32. At least a portion of the outer surface of the conductive portion 32 is covered by the insulating substance 34. The insulating substance 34 is formed of an insulating material and is an insulating particle. In this way, the conductive particles of the present invention may have an insulating substance disposed on the outer surface of the conductive portion. However, the conductive particles may not necessarily have an insulating substance. The conductive particles may not have a plurality of insulating substances.

Conductive part: The metal used to form the conductive part is not particularly limited. Examples of the metal include gold, silver, palladium, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, molybdenum, germanium, cadmium, silicon, tungsten, molybdenum and alloys thereof. In addition, examples of the metal include tin-doped indium oxide (ITO) and solder. From the viewpoint of further improving the connection reliability between electrodes, the metal is preferably a tin-containing alloy, nickel, palladium, copper or gold, preferably nickel or palladium.

In addition, since the conduction reliability can be effectively improved, the conductive portion and the outer surface portion of the conductive portion preferably contain nickel. The content of nickel in 100% by weight of the conductive portion containing nickel is preferably 10% by weight or more, more preferably 50% by weight or more, further preferably 60% by weight or more, further preferably 70% by weight or more, and particularly preferably 90% by weight or more. The content of nickel in 100% by weight of the conductive portion containing nickel may be 97% by weight or more, 97.5% by weight or more, or 98% by weight or more.

Furthermore, the surface of the conductive part is often oxidized to have hydroxyl groups. Generally speaking, the surface of the conductive part formed of nickel is oxidized to have hydroxyl groups. An insulating material can be arranged on the surface of the conductive part having hydroxyl groups (the surface of the conductive particles) through chemical bonds.

The conductive part may be formed of one layer like the conductive particles 1 and 31. The conductive part may also be formed of a plurality of layers like the conductive particles 21. That is, the conductive part may also have a laminated structure of two or more layers. In the case where the conductive part 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, and is more preferably a gold layer. In the case where the outermost layer is such a preferred conductive part, the connection resistance between the electrodes can be further effectively reduced. In addition, in the case where the outermost layer is a gold layer, the corrosion resistance can be further effectively improved.

The method for forming the conductive portion on the surface of the resin particles is not particularly limited. Examples of the method for forming the conductive portion include: a method using electroless plating, a method using electroplating, a method using physical evaporation, and a method of applying metal powder or a slurry containing metal powder and a binder on the surface of the resin particles. The method using electroless plating is preferred because the conductive portion can be formed simply. Examples of the method using physical evaporation include: vacuum evaporation, ion plating, and ion sputtering.

The particle size of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, and preferably 500 μm or less, more preferably 300 μm or less, further preferably 100 μm or less, further preferably 50 μm or less, and particularly preferably 30 μm or less. If the particle size of the conductive particles is above the lower limit and below the upper limit, when the conductive particles are used to connect electrodes, the contact area between the conductive particles and the electrodes is sufficiently large, and it is not easy to form conductive particles that aggregate when the conductive part is formed. In addition, the distance between the electrodes connected by the conductive particles will not become too large, and the conductive part will not be easily peeled off from the surface of the resin particles. Furthermore, when the particle size of the conductive particles is greater than or equal to the above lower limit and less than or equal to the above upper limit, the conductive particles can be suitably used for conductive materials.

The particle size of the conductive particles mentioned above refers to the diameter when the conductive particles are true spherical particles, and refers to the diameter when the conductive particles are assuming a true sphere with the same volume as the conductive particles when the conductive particles are other than true spherical particles.

The particle size of the conductive particles is preferably an average particle size, and more preferably a number average particle size. The particle size of the conductive particles is obtained by observing 50 random conductive particles using an electron microscope or an optical microscope and calculating the average value, or by using a particle size distribution measuring device. In the observation using an electron microscope or an optical microscope, the particle size of each conductive particle is obtained as the particle size measured in terms of a circle equivalent diameter. In the observation using an electron microscope or an optical microscope, the average particle size measured in terms of a circle equivalent diameter of 50 random conductive particles is almost equal to the average particle size measured in terms of a sphere equivalent diameter. In the particle size distribution measuring device, the particle size of each conductive particle is determined as the particle size measured in terms of spherical equivalent diameter. The particle size of the conductive particles is preferably calculated by the particle size distribution measuring device.

The thickness of the conductive part is preferably 0.005 μm or more, more preferably 0.01 μm or more, and preferably 10 μm or less, more preferably 1 μm or less, and further preferably 0.3 μm or less. The thickness of the conductive part is the thickness of the entire conductive part when the conductive part is multi-layered. If the thickness of the conductive part is above the lower limit and below the upper limit, sufficient conductivity can be obtained, and the conductive particles will not become too hard, and the conductive particles will be sufficiently deformed when connecting between electrodes.

In the case where the conductive portion is formed of a plurality of layers, the thickness of the conductive portion of the outermost layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, and preferably 0.5 μm or less, more preferably 0.1 μm or less. If the thickness of the conductive portion of the outermost layer is above the lower limit and below the upper limit, the outermost layer is evenly covered by the conductive portion, the corrosion resistance is sufficiently improved, and the connection resistance between the electrodes is sufficiently reduced. In addition, 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 conductive part can be measured, for example, by observing the cross section of the conductive particle using a transmission electron microscope (TEM). The thickness of the conductive part is preferably calculated by taking the average value of the thicknesses of any five locations of the conductive part as the thickness of the conductive part of one conductive particle, and more preferably by taking the average value of the thickness of the entire conductive part as the thickness of the conductive part of one conductive particle. The thickness of the conductive part is preferably calculated by calculating the average value of the thickness of the conductive part of each conductive particle for any ten conductive particles.

Core material: The conductive particles preferably have protrusions on the outer surface of the conductive portion. The conductive particles more preferably have a plurality of protrusions on the outer surface of the conductive portion. By providing the conductive particles with a plurality of protrusions on the outer surface of the conductive portion, the conduction reliability between the electrodes can be further improved. An oxide film is formed on the surface of the electrodes connected by the conductive particles. Furthermore, an oxide film is formed on the surface of the conductive portion of the conductive particles. By using the conductive particles having protrusions, the conductive particles are placed between the electrodes and then pressed together, whereby the oxide film is effectively excluded by the protrusions. Therefore, the electrodes and the conductive particles can be more securely in contact with each other, thereby further effectively reducing the connection resistance between the electrodes. Furthermore, when the conductive particles have insulating substances on their surfaces or when the conductive particles are dispersed in a binder resin and used as conductive materials, the protrusions of the conductive particles can effectively remove the insulating substances or the binder resin between the conductive particles and the electrodes, thereby further effectively improving the conduction reliability between the electrodes.

By embedding the core material into the conductive part, a plurality of protrusions can be easily formed on the outer surface of the conductive part. However, it is not necessary to use a core material to form protrusions on the surface of the conductive part of the conductive particle.

As methods for forming protrusions on the surface of the conductive particles, there are: a method of attaching a core material to the surface of a resin particle and then forming a conductive portion by electroless plating; a method of forming a conductive portion by electroless plating on the surface of a resin particle and then attaching a core material and then forming a conductive portion by electroless plating. In addition, the protrusions may be formed without using the core material.

As a method for forming the above-mentioned protrusions, the following methods can also be listed. A method of adding a core material in the middle stage of forming the conductive portion on the surface of the resin particle by electroless plating. As a method of forming the protrusions by electroless plating without using a core material, a method of generating a metal core by electroless plating, attaching the metal core to the surface of the resin particle or the conductive portion, and then forming the conductive portion by electroless plating.

The material of the core material is not particularly limited. As the material of the core material, for example, conductive materials and non-conductive materials can be listed. As the conductive material, metals, metal oxides, conductive non-metals such as zinc, and conductive polymers can be listed. As the conductive polymer, polyacetylene can be listed. As the non-conductive material, silicon dioxide, aluminum oxide, barium titanate, and zirconium oxide can be listed. Metals are preferred because they can improve conductivity and thus effectively reduce connection resistance. The core material is preferably metal particles. The metal used as the material of the core material can be appropriately used as the metal listed as the metal used to form the conductive part.

Insulating material: The conductive particles described above preferably further have an insulating material disposed on the outer surface of the conductive portion. In this case, if the conductive particles are used to connect electrodes, short circuits between adjacent electrodes can be further prevented. Specifically, when a plurality of conductive particles are in contact, an insulating material exists between the plurality of electrodes, thereby preventing short circuits between electrodes that are adjacent in the horizontal direction rather than between upper and lower electrodes. Furthermore, when connecting the electrodes, the conductive particles are pressurized by two electrodes, thereby easily removing the insulating material between the conductive portion of the conductive particles and the electrodes. When the conductive particles have a plurality of protrusions on the outer surface of the conductive portion, it is easier to remove insulating substances between the conductive portion of the conductive particles and the electrode.

In terms of being able to more easily remove the insulating substance when the electrodes are crimped, the insulating substance is preferably insulating particles.

Examples of the insulating material include polyolefin compounds, (meth)acrylate polymers, (meth)acrylate copolymers, block polymers, thermoplastic resins, crosslinked products of thermoplastic resins, thermosetting resins, and water-soluble resins. Only one type of the insulating material may be used, or two or more types may be used in combination.

Examples of the polyolefin compound include polyethylene, ethylene-vinyl acetate copolymer, and ethylene-acrylate copolymer. Examples of the (meth)acrylate polymer include polymethyl (meth)acrylate, polydodecyl (meth)acrylate, and polystearyl (meth)acrylate. Examples of the block polymer include polystyrene, styrene-acrylate copolymer, SB type styrene-butadiene block copolymer, and SBS type styrene-butadiene block copolymer, as well as hydrogenates thereof. Examples of the thermoplastic resin include ethylene polymers and ethylene copolymers. Examples of the thermosetting resin include epoxy resins, phenol resins, and melamine resins. As crosslinking agents of the thermoplastic resins, polyethylene glycol methacrylate, alkoxylated trihydroxymethylpropane methacrylate, or alkoxylated pentaerythritol methacrylate can be introduced. As water-soluble resins, polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinyl pyrrolidone, polyethylene oxide, and methylcellulose can be introduced. In addition, a chain transfer agent can be used to adjust the degree of polymerization. As chain transfer agents, mercaptan or carbon tetrachloride can be introduced.

As methods for configuring the insulating material on the surface of the conductive part, chemical methods, physical or mechanical methods, etc. can be cited. As the chemical method, for example, interfacial polymerization, suspension polymerization in the presence of particles, and emulsion polymerization can be cited. As the physical or mechanical method, spray drying, mixing, electrostatic adsorption, spraying, immersion, and vacuum evaporation can be cited. In terms of the insulating material not being easy to detach, it is preferred to configure the insulating material on the surface of the conductive part via chemical bonds.

The outer surface of the conductive part and the surface of the insulating material may also be coated with a compound having a reactive functional group. The outer surface of the conductive part and the surface of the insulating material may not be directly chemically bonded, but may be indirectly chemically bonded through a compound having a reactive functional group. After the carboxyl group is introduced to the outer surface of the conductive part, the carboxyl group may be chemically bonded to the functional group on the surface of the insulating material through a polymer electrolyte such as polyethyleneimine.

(Conductive material) The conductive material of the present invention comprises the conductive particles mentioned above, and an adhesive. The conductive particles mentioned above have the resin particles mentioned above, and a conductive portion arranged on the surface of the resin particles. The conductive particles mentioned above are preferably dispersed in an adhesive for use, and are preferably dispersed in an adhesive for use as a conductive material. The conductive material mentioned above is preferably an anisotropic conductive material. The conductive material mentioned above is preferably used for electrical connection between electrodes. The conductive material mentioned above is preferably a conductive material for circuit connection.

The above-mentioned adhesive resin is not particularly limited. As the above-mentioned adhesive resin, a well-known insulating resin can be used. The above-mentioned adhesive resin preferably contains a thermoplastic component (thermoplastic compound) or a curable component, and more preferably contains a curable component. As the above-mentioned curable component, a photocurable component and a thermocurable component can be listed. The above-mentioned photocurable component preferably contains a photocurable compound and a photopolymerization initiator. The above-mentioned thermocurable component preferably contains a thermocurable compound and a thermosetting agent. As the above-mentioned adhesive resin, for example, ethylene resins, thermoplastic resins, curable resins, thermoplastic block copolymers and elastomers can be listed. The above-mentioned adhesive resin can be used alone or in combination of two or more.

Examples of the above-mentioned ethylene resin include vinyl acetate resin, acrylic resin, and styrene resin. Examples of the above-mentioned thermoplastic resin include polyolefin resin, ethylene-vinyl acetate copolymer, and polyamide resin. Examples of the above-mentioned curable resin include epoxy resin, urethane resin, polyimide resin, and unsaturated polyester resin. Furthermore, the above-mentioned curable resin may be a room temperature curing resin, a heat curing resin, a light curing resin, or a moisture curing resin. The above-mentioned curable resin may also be used in combination with a curing agent. Examples of the thermoplastic block copolymer include styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, hydrogenated styrene-butadiene-styrene block copolymer, and hydrogenated styrene-isoprene-styrene block copolymer. Examples of the elastomer include styrene-butadiene copolymer rubber and acrylonitrile-styrene block copolymer rubber.

In addition to the conductive particles and the binder resin, the conductive material may also include various additives such as fillers, extenders, softeners, plasticizers, polymerizing catalysts, curing catalysts, colorants, antioxidants, thermal stabilizers, light stabilizers, ultraviolet absorbers, lubricants, antistatic agents, and flame retardants.

The method for dispersing the conductive particles in the binder resin may be a previously known dispersing method, and is not particularly limited. As the method for dispersing the conductive particles in the binder resin, for example, the following methods can be cited. A method in which the conductive particles are added to the binder resin and then dispersed by kneading using a planetary mixer or the like. A method in which the conductive particles are uniformly dispersed in water or an organic solvent using a homogenizer, and then added to the binder resin and dispersed by kneading using a planetary mixer or the like. A method in which the conductive particles are diluted with water or an organic solvent, and then added to the binder resin and dispersed by kneading using a planetary mixer or the like.

The viscosity (η25) of the conductive material at 25°C is preferably 30 Pa·s or more, more preferably 50 Pa·s or more, and preferably 400 Pa·s or less, more preferably 300 Pa·s or less. If the viscosity of the conductive material at 25°C is above the lower limit and below the upper limit, the connection reliability between the electrodes can be further effectively improved. The viscosity (η25) can be appropriately adjusted by the type and amount of the blended components.

The viscosity (η25) can be measured, for example, using an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co., Ltd.) under conditions of 25°C and 5 rpm.

The conductive material can be used in the form of a conductive paste and a conductive film. When the conductive material of the present invention is a conductive film, a conductive film containing conductive particles can be laminated to a film not containing conductive particles. The conductive paste is preferably an anisotropic conductive paste. The conductive film is preferably an anisotropic conductive film.

In 100 wt % of the conductive material, the content of the binder resin is preferably 10 wt % or more, more preferably 30 wt % or more, further preferably 50 wt % or more, particularly preferably 70 wt % or more, and preferably 99.99 wt % or less, more preferably 99.9 wt % or less. If the content of the binder resin is above the lower limit and below the upper limit, the conductive particles are efficiently arranged between the electrodes, and the connection reliability of the connection target components connected via the conductive material is further improved.

In 100 wt % of the conductive material, the content of the conductive particles is preferably 0.01 wt % or more, more preferably 0.1 wt % or more, and preferably 80 wt % or less, more preferably 60 wt % or less, further preferably 40 wt % or less, further preferably 20 wt % or less, and particularly preferably 10 wt % or less. If the content of the conductive particles is above the lower limit and below the upper limit, the connection resistance between the electrodes can be further effectively reduced, and the connection reliability between the electrodes can be further effectively improved.

(Connection structure)  A connection structure can be obtained by connecting the components to be connected using the above-mentioned conductive particles or a conductive material containing the above-mentioned conductive particles and an adhesive resin.

The connection structure comprises a first connection target member having a first electrode on its surface, a second connection target member having a second electrode on its surface, and a connection portion connecting the first connection target member and the second connection target member. In the connection structure, the connection portion is formed by conductive particles, or is formed by the conductive material comprising conductive particles and a binder resin. The conductive particles comprise the resin particles, and a conductive portion disposed on the surface of the resin particles. In the connection structure, the first electrode and the second electrode are electrically connected via the conductive particles.

When the conductive particles are used alone, the connecting portion itself is the conductive particles. That is, the first connecting component and the second connecting component are connected via the conductive particles. The conductive material used to obtain the connecting structure is preferably an anisotropic conductive material.

FIG. 4 is a cross-sectional view showing an example of a connection structure using conductive particles according to the first embodiment of the present invention.

The connection structure 41 shown in FIG4 includes a first connection target member 42, a second connection target member 43, and a connection portion 44 connecting the first connection target member 42 and the second connection target member 43. The connection portion 44 is formed of a conductive material including conductive particles 1 and a binder resin. In FIG4, for the convenience of illustration, the conductive particles 1 are briefly illustrated. Other conductive particles such as conductive particles 21 and 31 may be used instead of the conductive particles 1.

The first connection target component 42 has a plurality of first electrodes 42a on the surface (upper surface). The second connection target component 43 has a plurality of second electrodes 43a on the surface (lower surface). The first electrode 42a and the second electrode 43a are electrically connected by one or more conductive particles 1. Therefore, the first and second connection target components 42 and 43 are electrically connected by the conductive particles 1.

The manufacturing method of the above-mentioned connection structure is not particularly limited. As an example of the manufacturing method of the connection structure, there can be cited a method of heating and pressurizing the laminate after the above-mentioned conductive material is arranged between the first connection target component and the second connection target component. The pressure during the above-mentioned pressurization is preferably 40 MPa or more, more preferably 60 MPa or more, and preferably 90 MPa or less, and more preferably 70 MPa or less. The temperature during the above-mentioned heating is preferably 80°C or more, more preferably 100°C or more, and preferably 140°C or less, and more preferably 120°C or less.

The first connection target component and the second connection target component are not particularly limited. Specifically, the first connection target component and the second connection target component include: electronic components such as semiconductor chips, semiconductor packages, LED (light-emitting diode) chips, LED packages, capacitors and diodes, and electronic components such as resin films, printed circuit boards, flexible printed circuit boards, flexible flat cables, rigid flexible substrates, glass epoxy substrates, glass substrates, and circuit substrates. The first connection target component and the second connection target component are preferably electronic components.

The conductive material is preferably a conductive material used to connect electronic components. The conductive paste is a paste-like conductive material, and is preferably applied to the connecting component in a paste-like state.

The conductive particles, conductive materials and connecting materials can also be suitably used in touch panels. Therefore, the connecting component is preferably a flexible substrate or a connecting component with electrodes arranged on the surface of a resin film. The connecting component is preferably a flexible substrate, and preferably a connecting component with electrodes arranged on the surface of a resin film. When the flexible substrate is a flexible printed substrate, etc., the flexible substrate usually has electrodes on the surface.

Electrodes provided on the above-mentioned connecting object component include metal electrodes such as gold electrode, nickel electrode, tin electrode, aluminum electrode, copper electrode, molybdenum electrode, silver electrode, SUS (Steel Use Stainless Steel) electrode, and tungsten electrode. When the above-mentioned connecting object component is a flexible printed circuit board, the above-mentioned electrode is preferably a gold electrode, a nickel electrode, a tin electrode, a silver electrode, or a copper electrode. When the above-mentioned connecting object component is a glass substrate, the above-mentioned electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, or a tungsten electrode. Furthermore, when the electrode is an aluminum electrode, it may be an electrode formed of aluminum alone or an electrode in which an aluminum layer is layered on the surface 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, and Ga.

Furthermore, the resin particles can be suitably used as a spacer for a liquid crystal display element. The first component to be connected can be a component for a first liquid crystal display element. The second component to be connected can be a component for a second liquid crystal display element. The connecting portion can also be a sealing portion that seals the outer periphery of the first component for a liquid crystal display element and the second component for a liquid crystal display element in a state where the first component for a liquid crystal display element and the second component for a liquid crystal display element are facing each other.

The resin particles can also be used as a peripheral sealant for a liquid crystal display element. The liquid crystal display element comprises a first liquid crystal display element component and a second liquid crystal display element component. The liquid crystal display element further comprises: a sealing portion that seals the outer periphery of the first liquid crystal display element component and the second liquid crystal display element component in a state where the first liquid crystal display element component and the second liquid crystal display element component are opposite to each other; and a liquid crystal that is arranged on the inner side of the sealing portion and between the first liquid crystal display element component and the second liquid crystal display element component. The liquid crystal display element applies a liquid crystal dropping method, and the sealing portion is formed by thermally curing a sealant for the liquid crystal dropping method.

In the above-mentioned liquid crystal display element, the arrangement density of the liquid crystal display element spacers per 1 mm ² is preferably 10 pieces/mm ² or more, and preferably 1000 pieces/mm ² or less. If the above-mentioned arrangement density is 10 pieces/mm ² or more, the element gap becomes more uniform. If the above-mentioned arrangement density is 1000 pieces/mm ² or less, the contrast of the liquid crystal display element becomes better.

(Electronic component device) The above-mentioned resin particles or conductive particles can also be arranged between the first ceramic component and the second ceramic component at the outer periphery of the first ceramic component and the second ceramic component, and used as a gap control material and a conductive connecting material.

Fig. 5 is a cross-sectional view showing an example of an electronic component device using the resin particles of the present invention. Fig. 6 is a cross-sectional view showing an enlarged portion of a joint in the electronic component device shown in Fig. 5.

The electronic component device 81 shown in FIGS. 5 and 6 includes a first ceramic member 82 , a second ceramic member 83 , a bonding portion 84 , an electronic component 85 , and a lead frame 86 .

The first and second ceramic components 82 and 83 are respectively formed of ceramic materials. The first and second ceramic components 82 and 83 are, for example, shells. The first ceramic component 82 is, for example, a substrate. The second ceramic component 83 is, for example, a cover. The first ceramic component 82 has a convex portion protruding toward the side (upper side) of the second ceramic component 83 on the periphery. The first ceramic component 82 has a concave portion forming an internal space R for accommodating the electronic component 85 on the side (upper side) of the second ceramic component 83. Furthermore, the first ceramic component 82 may not have a convex portion. The second ceramic component 83 has a convex portion protruding toward the side (lower side) of the first ceramic component 82 on the periphery. The second ceramic component 83 has a concave portion forming an internal space R for accommodating the electronic component 85 on the side (lower side) of the first ceramic component 82. Furthermore, the second ceramic member 83 may not have the protrusion. The inner space R is formed by the first ceramic member 82 and the second ceramic member 83 .

The joint portion 84 joins the outer peripheral portion of the first ceramic member 82 and the outer peripheral portion of the second ceramic member 83. Specifically, the joint portion 84 joins the convex portion of the outer peripheral portion of the first ceramic member 82 and the convex portion of the outer peripheral portion of the second ceramic member 83.

The first and second ceramic members 82 and 83 are joined via the joint 84 to form a package. The package forms an internal space R. The joint 84 seals the internal space R in a liquid-tight and air-tight manner. The joint 84 is a sealing portion.

The electronic component 85 is disposed in the internal space R of the package. Specifically, the electronic component 85 is disposed on the first ceramic member 82. In this embodiment, two electronic components 85 are used.

The joint part 84 includes a plurality of resin particles 11 and glass 84B. The joint part 84 is formed using a joint material including a plurality of resin particles 11 and glass 84B which are different from glass particles. The joint material is a joint material for ceramic packaging. The joint material may also include the conductive particles instead of the resin particles.

The bonding material may include a solvent or a resin. In the bonding portion 84, glass particles such as glass 84B are solidified after being melted and bonded.

Electronic components include sensor components, MEMS (Micro Electro Mechanical System), and bare chips. The sensor components include pressure sensor components, acceleration sensor components, CMOS (Complementary Metal Oxide Semiconductor) sensor components, CCD (Charge Coupled Device) sensor components, and housings of the above sensor components.

The lead frame 86 is disposed between the outer periphery of the first ceramic member 82 and the outer periphery of the second ceramic member 83. The lead frame 86 extends toward the inner space R side and the outer space side of the package. The terminal of the electronic component 85 is electrically connected to the lead frame 86 via a wire.

The joint portion 84 directly joins part of the outer periphery of the first ceramic component 82 and the outer periphery of the second ceramic component 83, and indirectly joins part of the outer periphery. Specifically, the joint portion 84 indirectly joins the outer periphery of the first ceramic component 82 and the outer periphery of the second ceramic component 83 via the lead frame 86 at a portion where the lead frame 86 exists between the outer periphery of the first ceramic component 82 and the outer periphery of the second ceramic component 83. At a portion where the lead frame 86 exists between the outer periphery of the first ceramic component 82 and the outer periphery of the second ceramic component 83, the first ceramic component 82 is in contact with the lead frame 86, and the lead frame 86 is in contact with the first ceramic component 82 and the joint portion 84. Furthermore, the joint portion 84 is in contact with the lead frame 86 and the second ceramic component 83, and the second ceramic component 83 is in contact with the joint portion 84. The bonding portion 84 directly bonds the outer periphery of the first ceramic member 82 and the outer periphery of the second ceramic member 83 at a portion where the lead frame 86 does not exist between the outer periphery of the first ceramic member 82 and the outer periphery of the second ceramic member 83. The bonding portion 84 is in contact with the first ceramic member 82 and the second ceramic member 83 at a portion where the lead frame 86 does not exist between the outer periphery of the first ceramic member 82 and the outer periphery of the second ceramic member 83.

In the portion where the lead frame 86 exists between the outer periphery of the first ceramic component 82 and the outer periphery of the second ceramic component 83 , the gap distance between the outer periphery of the first ceramic component 82 and the outer periphery of the second ceramic component 83 is controlled by the plurality of resin particles 11 included in the joint portion 84 .

The joint portion only needs to directly or indirectly join the outer periphery of the first ceramic component to the outer periphery of the second ceramic component. Furthermore, an electrical connection method other than a lead frame can also be used.

The electronic component device may be, for example, the electronic component device 81, which includes a first ceramic component formed of a ceramic material, a second ceramic component formed of a ceramic material, a joint, and an electronic component. In the electronic component device, the joint may directly or indirectly join the outer periphery of the first ceramic component to the outer periphery of the second ceramic component. In the electronic component device, a package may be formed by joining the first and second ceramic components via the joint. In the electronic component device, the electronic component may be arranged in an internal space of the package, and the joint may include a plurality of resin particles and glass.

In addition, as the bonding material used in the electronic component device 81, the above-mentioned ceramic package bonding material can be used to form the above-mentioned bonding part in the above-mentioned electronic component device, and includes resin particles and glass. Furthermore, an electrical connection method that only includes resin particles and does not include glass can also be adopted. In addition, the above-mentioned bonding part can also include the above-mentioned conductive particles instead of the above-mentioned resin particles.

The present invention is specifically described below by way of examples and comparative examples. The present invention is not limited to the following examples.

(Example 1)  (1) Preparation of resin particles  Prepare polystyrene (PS) particles with an average particle size of 0.80 μm as seed particles. Mix 3.9 parts by weight of the above-mentioned polystyrene particles, 500 parts by weight of ion-exchange water, and 120 parts by weight of a 5 wt% aqueous solution of polyvinyl alcohol to prepare a mixed solution (seed particle dispersion). Disperse the above-mentioned mixed solution by ultrasound, put it into a separable flask, and stir it evenly.

Divinylbenzene ("DVB960" manufactured by NS Styrene Monomer) was prepared as a crosslinking compound. 2 parts by weight of 2,2'-azobis(methyl isobutyrate) ("V-601" manufactured by Wako Junyaku Industries) and 2 parts by weight of benzoyl peroxide ("Nyper BW" manufactured by NOF Corporation) were added to 100 parts by weight of divinylbenzene, and 8 parts by weight of triethanolamine lauryl sulfate, 100 parts by weight of ethanol, and 1000 parts by weight of ion-exchanged water were added to prepare an emulsion.

The emulsion was further added to the mixed solution in the separable flask and stirred for 4 hours to allow the seed particles to absorb the monomer, thereby obtaining a suspension containing the seed particles swollen with the monomer.

Thereafter, 490 parts by weight of a 5% by weight aqueous solution of polyvinyl alcohol was added, and heating was started to react at 85° C. for 10 hours to obtain resin particles.

(2) Preparation of Conductive Particles The obtained resin particles were washed and graded, and then dried. Thereafter, a nickel layer was formed on the surface of the obtained resin particles by electroless plating to prepare conductive particles. The thickness of the nickel layer was 0.1 μm.

(3) Preparation of conductive material (anisotropic conductive paste) To prepare conductive material (anisotropic conductive paste), prepare the following materials.

(Materials for conductive material (anisotropic conductive paste))  Thermosetting compound A: Epoxy compound ("EP-3300P" manufactured by Nagase ChemteX)  Thermosetting compound B: Epoxy compound ("EPICLON HP-4032D" manufactured by DIC)  Thermosetting compound C: Epoxy compound ("Epogosey PT" manufactured by Yokkaichi Synthetics, polytetramethylene glycol diglycidyl ether)  Thermosetting agent: Thermal cation generator (San-Aid "SI-60" manufactured by Sanshin Chemical Co., Ltd.)  Filler: Silicon dioxide (average particle size 0.25 μm)

The conductive material (anisotropic conductive paste) was prepared as follows.

(Preparation method of conductive material (anisotropic conductive paste)) A formulation is obtained by preparing 10 parts by weight of thermosetting compound A, 10 parts by weight of thermosetting compound B, 15 parts by weight of thermosetting compound C, 5 parts by weight of thermosetting agent, and 20 parts by weight of filler. Furthermore, after adding the obtained conductive particles in such a manner that the content becomes 10% by weight in 100% by weight of the formulation, the mixture is stirred at 2000 rpm for 5 minutes using a planetary stirrer to obtain a conductive material (anisotropic conductive paste).

(4) Preparation of connection structure: A glass substrate having an aluminum electrode pattern with an L/S ratio of 20 μm/20 μm on the upper surface is prepared as the first connection target component. Also, a semiconductor chip having a gold electrode pattern with an L/S ratio of 20 μm/20 μm on the lower surface (gold electrode thickness 20 μm) is prepared as the second connection target component.

The conductive material (anisotropic conductive paste) just produced is applied to the upper surface of the above-mentioned glass substrate in a manner that the thickness becomes 30 μm, thereby forming a conductive material (anisotropic conductive paste) layer. Subsequently, the above-mentioned semiconductor chip is stacked on the upper surface of the conductive material (anisotropic conductive paste) layer in a manner that the electrodes face each other. Thereafter, while adjusting the temperature of the pressurized heating head in a manner that the temperature of the conductive material (anisotropic conductive paste) layer becomes 170°C, the pressurized heating head is placed on the upper surface of the semiconductor chip, and the conductive material (anisotropic conductive paste) layer is cured under the conditions of 170°C, 1 MPa, and 15 seconds to obtain a connection structure.

(Example 2)  When preparing resin particles, 100 parts by weight of divinylbenzene (cross-linking compound) is replaced with 50 parts by weight of divinylbenzene ("DVB960" manufactured by NS Styrene Monomer) and 50 parts by weight of pentaerythritol triacrylate ("Light acrylate PE-4A" manufactured by Kyoeisha Chemical Co., Ltd.). Except for the above changes, resin particles, conductive particles, conductive materials and connecting structures are obtained in the same manner as in Example 1.

(Example 3)  When preparing resin particles, 100 parts by weight of divinylbenzene (cross-linking compound) is replaced with 80 parts by weight of polytetramethylene glycol diacrylate ("Light acrylate PTMGA-250" manufactured by Kyoeisha Chemical Co., Ltd.). When preparing resin particles, 20 parts by weight of styrene (manufactured by NS Styrene Monomer Co., Ltd.) is further used as a non-cross-linking compound. Except for the above changes, resin particles, conductive particles, conductive materials and connecting structures are obtained in the same manner as in Example 1.

(Example 4)  When preparing resin particles, 100 parts by weight of divinylbenzene (cross-linking compound) is replaced with 60 parts by weight of 1,4-butanediol dimethacrylate ("LIGHT ESTER 1.4BG" manufactured by Kyoeisha Chemical Co., Ltd.). When preparing resin particles, 40 parts by weight of isobutyl acrylate ("Light acrylate IB-XA" manufactured by Kyoeisha Chemical Co., Ltd.) is further used as a non-cross-linking compound. Except for the above changes, resin particles, conductive particles, conductive materials and connecting structures are obtained in the same manner as in Example 1.

(Example 5)  When preparing resin particles, 100 parts by weight of divinylbenzene (cross-linking compound) is replaced with 30 parts by weight of polytetramethylene glycol diacrylate ("Light acrylate PTMGA-250" manufactured by Kyoeisha Chemical Co., Ltd.). When preparing resin particles, 70 parts by weight of isobutyl acrylate ("Light acrylate IB-XA" manufactured by Kyoeisha Chemical Co., Ltd.) is further used as a non-cross-linking compound. Except for the above changes, resin particles, conductive particles, conductive materials and connecting structures are obtained in the same manner as in Example 1.

(Example 6)  When preparing resin particles, 100 parts by weight of divinylbenzene (cross-linking compound) is replaced with 50 parts by weight of glycerol dimethacrylate ("LIGHT ESTER G-101P" manufactured by Kyoeisha Chemical Co., Ltd.). When preparing resin particles, 50 parts by weight of cyclohexyl methacrylate ("LIGHT ESTER CH" manufactured by Kyoeisha Chemical Co., Ltd.) is further used as a non-cross-linking compound. Except for the above changes, resin particles, conductive particles, conductive materials and connecting structures are obtained in the same manner as in Example 1.

(Example 7)  When preparing resin particles, 100 parts by weight of divinylbenzene (cross-linking compound) is replaced with 20 parts by weight of divinylbenzene ("DVB960" manufactured by NS Styrene Monomer). When preparing resin particles, 79.5 parts by weight of cyclohexyl methacrylate ("LIGHT ESTER CH" manufactured by Kyoeisha Chemical Co., Ltd.) as a non-cross-linking compound and 0.5 parts by weight of methacrylic acid ("LIGHT ESTER A" manufactured by Kyoeisha Chemical Co., Ltd.) as a polymerizable compound having a polar functional group are further used. Except for the above changes, resin particles, conductive particles, conductive materials and connecting structures are obtained in the same manner as in Example 1.

(Example 8)  When preparing resin particles, polystyrene particles (seed particles) having an average particle size of 0.80 μm are changed to polystyrene particles having an average particle size of 3 μm. When preparing resin particles, 100 parts by weight of divinylbenzene (cross-linking compound) are changed to 5 parts by weight of polytetramethylene glycol diacrylate ("Light acrylate PTMGA-250" manufactured by Kyoeisha Chemical Co., Ltd.). When preparing resin particles, 65 parts by weight of isobutyl acrylate ("Light acrylate IB-XA" manufactured by Kyoeisha Chemical Co., Ltd.) as a non-cross-linking compound and 30 parts by weight of 2-methylacryloylethyl phosphate ("LIGHT ESTER P-1M" manufactured by Kyoeisha Chemical Co., Ltd.) as a polymerizable compound having a polar functional group are used. Except for the above changes, resin particles were obtained in the same manner as in Example 1.

When making conductive particles, the thickness of the nickel layer was changed from 0.1 μm to 1 μm.

In addition to the above changes, conductive particles, conductive materials and connection structures are obtained.

(Comparative Example 1) When preparing resin particles, 100 parts by weight of divinylbenzene (cross-linking compound) is replaced with 20 parts by weight of divinylbenzene ("DVB960" manufactured by NS Styrene Monomer). When preparing resin particles, 80 parts by weight of cyclohexyl methacrylate ("LIGHT ESTER CH" manufactured by Kyoeisha Chemical Co., Ltd.) is further used as a non-cross-linking compound. Except for the above changes, resin particles, conductive particles, conductive materials and connecting structures are obtained in the same manner as in Example 1.

(Comparative Example 2)  When preparing resin particles, polystyrene particles (seed particles) with an average particle size of 0.80 μm are changed to polystyrene particles with an average particle size of 3 μm. When preparing resin particles, 100 parts by weight of divinylbenzene (cross-linking compound) are changed to 7.5 parts by weight of polytetramethylene glycol diacrylate ("Light acrylate PTMGA-250" manufactured by Kyoeisha Chemical Co., Ltd.). When preparing resin particles, 82.5 parts by weight of isobutyl acrylate ("Light acrylate IB-XA" manufactured by Kyoeisha Chemical Co., Ltd.) are further used as a non-cross-linking compound. Except for the above changes, the resin particles are obtained in the same manner as in Example 1.

When making conductive particles, the thickness of the nickel layer was changed from 0.1 μm to 1 μm.

In addition to the above changes, conductive particles, conductive materials and connection structures are obtained.

(Evaluation)  (1) Particle size of resin particles and conductive particles  The particle size of the obtained resin particles and conductive particles was measured using a precision particle size distribution measuring device ("Multisizer 3" manufactured by Beckman Coulter).

(2) Compressive modulus of resin particles The compressive modulus of the obtained resin particles (10% K value and 30% K value) was measured by the above method and using a micro compression tester ("Fischerscope H-100" manufactured by Fischer).

(3) Compression recovery rate of resin particles The compression recovery rate of the obtained resin particles was measured by the above method and using a micro compression tester ("Fischerscope H-100" manufactured by Fischer).

(4) Time-of-flight secondary ion mass spectrometry (TOF-SIMS) of resin particles The obtained resin particles were used to perform time-of-flight secondary ion mass spectrometry (TOF-SIMS). Specifically, the analysis was performed in the following manner. The TOF-SIMS used the "TOF-SIMS 5" manufactured by ION TOF. In order to use the TOF-SIMS analysis device to measure the ^OH- ion intensity and total ion intensity on the outer surface of the resin particles, a Bi ³⁺ ion gun was used as the primary ion source for measurement, and the measurement was performed under the condition of 25 keV. Sputtering is the process of introducing an inert gas such as argon into a vacuum, applying a negative voltage to the target to generate a glow discharge, ionizing the inert gas atoms and grinding the target surface. By performing sputtering twice, TOF-SIMS was used to obtain the detection results of the ion intensity in a region of about 2 nm thickness from the outer surface of the resin particle to the inner side.

Based on the obtained results, the ratio of the intensity of ^OH- ions to the total intensities of all negative ions (intensity of OH- ions/total intensities of all negative ions) was calculated when a negative ion mass spectrum was obtained by time-of-flight secondary ion mass spectrometry (TOF ^- SIMS) on the outer surface of the above-mentioned resin particles.

(5) Aggregation of resin particles The aggregation of resin particles was evaluated by measuring the sedimentation rate when the obtained resin particles were mixed with an organic solvent and left to stand. 2.5 g of the obtained resin particles were mixed with 25 mL of acetone to prepare a mixed solution, and the prepared mixed solution was dispersed by ultrasound for 1 minute using an ultrasonic cleaner ("VS-1003" manufactured by AS ONE). Thereafter, the mixture was placed in a 20 mL glass measuring cylinder and left to stand. The sedimentation of the resin particles was confirmed every 60 minutes to calculate the measured sedimentation rate. The ratio of the theoretical sedimentation velocity to the measured sedimentation velocity ([theoretical sedimentation velocity (m/h)/measured sedimentation velocity value (m/h)]) was calculated and judged according to the following criteria.

The theoretical sedimentation rate is calculated using the Stokes equation. This equation is used when it is assumed that a true spherical particle exists as a single particle. However, since it does not include the slurry concentration, it is not considered.

Theoretical sedimentation velocity (m ^{/h) = Dp2} _{( ρp} - _ρf ) g/18η _Dp : Resin particle size (m) _ρp : Resin particle density (kg/ ^m3 ) _ρf : Acetone density (kg/ ^m3 ): 784 kg/ ^m3 g: Gravitational acceleration (m/s) η: Acetone viscosity (kg/m・s): 0.00032 kg/m・s

The density of the resin particles was measured using a dry automatic density meter ("AccuPyc" manufactured by Shimadzu Corporation). The density of the resin particles was measured using the following resin particles, which were obtained by immersing 1 g of the resin particles in 100 g of methanol at 25°C for 20 hours and then vacuum drying at 40°C for 12 hours.

[Criteria for determining the aggregation of resin particles] ○: The ratio (theoretical sedimentation velocity (m/h)/measured sedimentation velocity (m/h)) is less than 0.55 (aggregates formed by the aggregation of resin particles are not observed at all) △: The ratio (theoretical sedimentation velocity (m/h)/measured sedimentation velocity (m/h)) is 0.55 or more and less than 0.75 (aggregates formed by the aggregation of resin particles are slightly observed) ×: The ratio (theoretical sedimentation velocity (m/h)/measured sedimentation velocity (m/h)) is 0.75 or more (aggregates formed by the aggregation of resin particles are observed)

(6) Thickness of the conductive part The obtained conductive particles were added to "Technovit 4000" manufactured by Kulzer in a content of 30% by weight, dispersed, and an embedded resin body for inspection was prepared. An ion milling device ("IM4000" manufactured by Hitachi High-Technologies Corporation) was used to cut a cross section of the conductive particles dispersed in the embedded resin body for inspection through the vicinity of the center.

Then, using a field emission transmission electron microscope (FE-TEM) ("JEM-ARM200F" manufactured by NEC Corporation), the image magnification was set to 50,000 times, 10 conductive particles were randomly selected, and the conductive part of each conductive particle was observed. The thickness of the conductive part in each conductive particle was measured, and the arithmetic average was taken, and the obtained value was set as the thickness of the conductive part.

(7) Adhesion between resin particles and conductive parts. For the obtained connection structure, the conductive particles in the connection part were observed using a scanning electron microscope ("Regulus 8220" manufactured by Hitachi High-Technologies Corporation). For the conductive part arranged on the surface of the resin particle, it was confirmed whether the conductive part was broken or peeled off. The number of conductive particles observed was 100. The adhesion between the resin particles and the conductive part was determined according to the following criteria.

[Criteria for determining the adhesion between the resin particles and the conductive part]  ○○○: The number of conductive particles that cracked or peeled off the conductive part is 0  ○○: The number of conductive particles that cracked or peeled off the conductive part is more than 0 and less than 15  ○: The number of conductive particles that cracked or peeled off the conductive part is more than 15 and less than 30  △: The number of conductive particles that cracked or peeled off the conductive part is more than 30 and less than 50  ×: The number of conductive particles that cracked or peeled off the conductive part is more than 50

(8) Connection reliability (between upper and lower electrodes) The connection resistance between the upper and lower electrodes of 100 connection structures was measured using the four-terminal method. The average value of the connection resistance was calculated. Furthermore, based on the relationship of voltage = current × resistance, the voltage when a certain current flows was measured to determine the connection resistance. The connection reliability was determined based on the following criteria.

[Connection reliability criteria] ○○○: The average value of the connection resistance is 1.5 Ω or less ○○: The average value of the connection resistance exceeds 1.5 Ω and is 2.0 Ω or less ○: The average value of the connection resistance exceeds 2.0 Ω and is 5.0 Ω or less △: The average value of the connection resistance exceeds 5.0 Ω and is 10 Ω or less ×: The average value of the connection resistance exceeds 10 Ω

(9) Connection reliability after high temperature and high humidity conditions. The 100 connection structures obtained in the evaluation of connection reliability in (8) above were placed at 85°C and 85%RH for 100 hours. The 100 connection structures after placement were evaluated to see whether poor conduction between the upper and lower electrodes occurred. The connection reliability after high temperature and high humidity conditions was determined based on the following criteria.

[Criteria for determining connection reliability after high temperature and high humidity conditions]  ○○: Among 100 connection structures, the number of poor conduction is 1 or less  ○: Among 100 connection structures, the number of poor conduction is 2 or more but less than 5  △: Among 100 connection structures, the number of poor conduction is 6 or more but less than 10  ×: Among 100 connection structures, the number of poor conduction is 11 or more

The materials used in the production of the resin particles of Examples 1 to 8 and Comparative Examples 1 and 2 are shown in Tables 1 and 2. The results are shown in Tables 3 and 4 below.

[Table 1] Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Embodiment 5 Particle dispersion Seed Particles Type PS particles PS particles PS particles PS particles PS particles Average particle size (μm) 0.8 0.8 0.8 0.8 0.8 Emulsion Cross-linked compounds Type Divinylbenzene Divinylbenzene Polytetramethylene glycol diacrylate 1,4-Butanediol dimethacrylate Polytetramethylene glycol diacrylate Mixing amount (weight parts) 100 50 80 60 30 Type - Pentaerythritol triacrylate - - - Mixing amount (weight parts) - 50 - - - Non-crosslinked compounds Type - - Styrene Isobutyl acrylate Isobutyl acrylate Mixing amount (weight parts) - - 20 40 70 Polymerizable compounds with polar functional groups Type - - - - - Mixing amount (weight parts) - - - - -

[Table 2] Embodiment 6 Embodiment 7 Embodiment 8 Comparison Example 1 Comparison Example 2 Particle dispersion Seed Particles Type PS particles PS particles PS particles PS particles PS particles Average particle size (μm) 0.8 0.8 3 0.8 3 Emulsion Cross-linked compounds Type Glyceryl dimethacrylate Divinylbenzene Polytetramethylene glycol diacrylate Divinylbenzene Polytetramethylene glycol diacrylate Mixing amount (weight parts) 50 20 5 20 7.5 Type - - - - - Mixing amount (weight parts) - - - - - Non-crosslinked compounds Type Cyclohexyl methacrylate Cyclohexyl methacrylate Isobutyl acrylate Cyclohexyl methacrylate Isobutyl acrylate Mixing amount (weight parts) 50 79.5 65 80 82.5 Polymerizable compounds with polar functional groups Type - Methacrylic acid 2-Methacryloyloxyethyl acid phosphate - - Mixing amount (weight parts) - 0.5 30 - -

[Table 3] Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Embodiment 5 Evaluation of resin particles Particle size (μm) 5.0 3.1 25.4 3.2 3.3 10%K value (N/mm ² ) 5280 4390 690 3060 2680 30%K value (N/mm ² ) 5050 3620 390 2450 1320 Compression recovery rate (%) 60 45 55 36 25 Ratio (intensity of OH ^- ions/total intensities of all negative ions) (×10 ^{- 2} ) 4.8 8.3 4.2 3.8 3.1 Agglutination ○ ○ ○ ○ ○ Evaluation of Conductive Particles Particle size (μm) 5.1 3.2 25.5 3.3 3.4 Thickness of conductive part (μm) 0.1 0.1 0.1 0.1 0.1 Adhesion between resin particles and conductive parts ○○ ○○○ ○○ ○○ ○ Evaluation of connection structures Connection reliability ○ ○○ ○ ○○ ○ Connection reliability (after high temperature and high humidity) ○ ○○ ○ ○ ○

[Table 4] Embodiment 6 Embodiment 7 Embodiment 8 Comparison Example 1 Comparison Example 2 Evaluation of resin particles Particle size (μm) 3.5 2.1 20.2 2.1 20.3 10%K value (N/mm ² ) 4070 3300 2130 3160 2200 30%K value (N/mm ² ) 2360 1430 760 1450 740 Compression recovery rate (%) 25 13 7 12 7 Ratio (intensity of OH ^- ions/total intensities of all negative ions) (×10 ^{- 2} ) 6.2 5.9 7.4 1.8 1.2 Agglutination ○ ○ ○ △ × Evaluation of Conductive Particles Particle size (μm) 3.6 2.2 21.2 2.2 21.3 Thickness of conductive part (μm) 0.1 0.1 1 0.1 1 Adhesion between resin particles and conductive parts ○○○ ○○○ ○○○ △ × Evaluation of connection structures Connection reliability ○○○ ○○○ ○○○ ○ △ Connection reliability (after high temperature and high humidity) ○○ ○○ ○○ △ ×

(10) Example of use as a spacer for gap control Preparation of a bonding material for ceramic packaging: The following bonding material for ceramic packaging is obtained, which includes 30 parts by weight of the resin particles obtained in Examples 1 to 8 and 70 parts by weight of glass (composition: Ag-V-Te-W-P-W-Ba-O, melting point 264°C).

Production of electronic component device: Using the obtained bonding material, the electronic component device shown in FIG. 5 is produced. Specifically, the bonding material is applied to the outer periphery of the first ceramic component by screen printing. Thereafter, the second ceramic component is arranged oppositely, and the bonding portion is irradiated with a semiconductor laser for baking, thereby bonding the first ceramic component and the second ceramic component.

In the obtained electronic component device, the interval between the first ceramic component and the second ceramic component is well controlled. Also, the obtained electronic component device operates well. Also, the airtightness inside the package is well maintained. Also, the resin particles are well dispersed in the joint portion.

1: Conductive particles 2: Conductive part 11: Resin particles 21: Conductive particles 22: Conductive part 22A: First conductive part 22B: Second conductive part 31: Conductive particles 31a: Protrusion 32: Conductive part 32a: Protrusion 33: Core material 34: Insulating material 41: Connecting structure 42: First connecting component 42a: First electrode 43: Second connecting component 43a: Second electrode 44: Connecting part 81: Electronic component device 82: First ceramic component 83: Second ceramic component 84: Joint 84B: Glass 85: Electronic component 86: Lead frame R: Internal space

Figure 1 is a cross-sectional view showing the conductive particles of the first embodiment of the present invention. Figure 2 is a cross-sectional view showing the conductive particles of the second embodiment of the present invention. Figure 3 is a cross-sectional view showing the conductive particles of the third embodiment of the present invention. Figure 4 is a cross-sectional view showing an example of a connection structure using the conductive particles of the first embodiment of the present invention. Figure 5 is a cross-sectional view showing an example of an electronic component device using the resin particles of the present invention. Figure 6 is a cross-sectional view showing an enlarged portion of the joint in the electronic component device shown in Figure 5.

1: Conductive particles

2: Conductive part

11: Resin particles

Claims (8)

A conductive particle comprises a resin particle and a conductive portion disposed on the surface of the resin particle, wherein the conductive particle has protrusions on the outer surface of the conductive portion, wherein the resin particle is a polymer of a plurality of polymerizable components of polymerizable compounds, wherein the polymerizable components constituting the polymer include a crosslinking compound and a polymerizable compound having a polar functional group, wherein the content of the crosslinking compound is less than 30% by weight in 100% by weight of the polymerizable components, and the content of the polymerizable compound having a polar functional group is 0.5% to 30% by weight in 100% by weight of the polymerizable components, and wherein the ratio of the intensity of OH- ^ions to the total intensity of all negative ions in the outer surface of the resin particle obtained by time-of-flight secondary ion mass spectrometry is 2.0×10 ^-2 or above. The conductive particles of claim 1, wherein the compressive elastic modulus of the resin particles when compressed by 10% is greater than 500 N/mm ² and less than 4500 N/mm ² . The conductive particles of claim 1, wherein the compressive elastic modulus of the resin particles when compressed by 30% is greater than 300 N/mm ² and less than 4000 N/mm ² . The conductive particle of any one of claims 1 to 3, wherein the polymerizable compound having a polar functional group includes a polymerizable compound having a hydroxyl group, a polymerizable compound having a carboxyl group, or a polymerizable compound having a phosphate group. The conductive particles of any one of claims 1 to 3, wherein the cross-linking compound comprises divinylbenzene, tetramethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, glycerol di(meth)acrylate, or 2-(meth)acryloyloxyethyl acid phosphate. The conductive particle of any one of claims 1 to 3 further comprises an insulating material disposed on the outer surface of the conductive portion. A conductive material comprising conductive particles as described in any one of claims 1 to 6, and a binder resin. A connection structure, comprising: a first connection target component having a first electrode on its surface, a second connection target component having a second electrode on its surface, and a connection portion connecting the first connection target component and the second connection target component, wherein the connection portion is formed by the conductive particles as described in any one of claims 1 to 6, or by the conductive material comprising the conductive particles and a binder resin, and the first electrode and the second electrode are electrically connected via the conductive particles.