Conductive particles, conductive materials, anisotropic conductive materials, and connection structures

Abstract

Provided are conductive particles that can increase saturation magnetization and reduce remanent magnetization, and can increase conduction reliability when electrically connecting electrodes.　Each conductive particle according to the present invention comprises a resin particle and a conductive part disposed on an outer side of an outer surface of the resin particle, and also comprises a magnetic body part including a magnetic body disposed between the resin particle and the conductive part, and a ratio of the remanent magnetization to the saturation magnetization in the conductive particle is 0.4 or less (configuration A), or the conductive part comprises a magnetic body, and the ratio of the remanent magnetization to the saturation magnetization in the conductive particle is 0.4 or less (configuration B), or the resin particle comprises a magnetic body (configuration C).

Description

Technical Field

[0001] The present invention relates to conductive particles that can be used for electrical connection between electrodes and the like. The present invention also relates to a conductive material and a connection structure using the above conductive particles.

Background Art

[0002] Anisotropic conductive materials such as anisotropic conductive pastes and anisotropic conductive films are widely known. In the above anisotropic conductive materials, conductive particles are dispersed in a binder resin. Further, as the above conductive particles, conductive particles having a base material particle and a conductive portion disposed on the surface of the base material particle may be used.

[0003] The above anisotropic conductive materials are used to obtain various connection structures. Examples of the connection using the above anisotropic conductive materials include connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), connection between a semiconductor chip and a flexible printed circuit board (COF (Chip on Film)), connection between a semiconductor chip and a glass substrate (COG (Chip on Glass)), and connection between a flexible printed circuit board and a glass epoxy substrate (FOB (Film on Board)).

[0004] Further, as the above conductive particles, as shown in Patent Documents 1 and 2 below, conductive particles having magnetism may be used.

[0005] Patent Document 1 below describes magnetic conductive particles at least partially composed of a magnetic material and capable of being magnetized as the above magnetic conductive particles. Patent Document 1 also describes, as the magnetic conductive particles, gold / nickel-coated resin particles, nickel-coated resin particles, nickel metal particles, phosphorus element-containing nickel-coated resin particles, and the like.

[0006] Patent Document 2 below discloses conductive particles including mother particles and insulating sub-particles that coat the surface of the mother particles. The mother particles have a plastic core and a plating layer that coats the surface of the plastic core. The plating layer has a nickel / phosphorus alloy layer. The particle diameter of the mother particles is 2.0 μm or more and 3.0 μm or less, and the saturation magnetization of the mother particles is 45 emu / cm 3 or less, and the particle diameter of the insulating sub-particles is 180 nm or more and 500 nm or less.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] As conductive particles, magnetic conductive particles may be used. However, with conventional conductive particles such as those described in Patent Documents 1 and 2, it is difficult to exhibit both characteristics of increasing the saturation magnetization and decreasing the residual magnetization.

[0009] With conductive particles having a low saturation magnetization, for example, it is difficult to arrange them well between the upper and lower electrodes to be connected by a magnetic field.

[0010] Also, with conductive particles having a high residual magnetization, for example, magnetic aggregation of the conductive particles is likely to occur.

[0011] Furthermore, with conventional magnetic conductive particles, it is difficult to reduce the coefficient of variation (CV value) of the particle diameter of the conductive particles. When the coefficient of variation of the particle diameter of the conductive particles is large, a short circuit may occur between the lateral electrodes that should not be connected, and a short circuit is particularly likely to occur between the electrodes with a fine pitch.

[0012] An object of the present invention is to provide conductive particles that can increase the saturation magnetization, can decrease the residual magnetization, and can further improve the conduction reliability when electrically connecting between electrodes. Another object of the present invention is to provide a conductive material and a connection structure using the above conductive particles.

Means for Solving the Problems

[0013] According to a broad aspect of the present invention, there are provided conductive particles including resin particles and a conductive portion disposed outside the outer surface of the resin particles, and having the following Configuration A, Configuration B, or Configuration C.

[0014] Configuration A: including a magnetic body portion containing a magnetic body disposed between the resin particles and the conductive portion, and the ratio of the residual magnetization to the saturation magnetization in the conductive particles is 0.4 or less. Configuration B: the conductive portion contains a magnetic body, and the ratio of the residual magnetization to the saturation magnetization in the conductive particles is 0.4 or less. Configuration C: the resin particles contain a magnetic body.

[0015] In a specific aspect of the conductive particles according to the present invention, the conductive particles have the Configuration A.

[0016] In a specific aspect of the conductive particles according to the present invention, the conductive particles have the Configuration B.

[0017] In a specific aspect of the conductive particles according to the present invention, the conductive particles have the Configuration C.

[0018] In a specific aspect of the conductive particles according to the present invention, in 100% by volume of the conductive particles, the content of the magnetic body contained in the conductive particles is 5% by volume or more and 85% by volume or less.

[0019] In a specific aspect of the conductive particles according to the present invention, in 100% by weight of the conductive particles, the content of the magnetic material contained in the conductive particles is 10% by weight or more and 99% by weight or less.

[0020] In a specific aspect of the conductive particles according to the present invention, the particle diameter of the conductive particles is 0.1 μm or more and 1000 μm or less.

[0021] In a specific aspect of the conductive particles according to the present invention, the magnetic material is a metal or a metal oxide.

[0022] In a specific aspect of the conductive particles according to the present invention, the magnetic material includes iron, cobalt, ferrite, nickel, or an alloy thereof.

[0023] In a specific aspect of the conductive particles according to the present invention, the conductive particles further include an insulating material disposed on the outer surface of the conductive portion.

[0024] In a specific aspect of the conductive particles according to the present invention, the conductive particles have protrusions on the outer surface of the conductive portion.

[0025] According to a broad aspect of the present invention, there is provided a conductive material including the above-described conductive particles and a binder resin.

[0026] According to a broad aspect of the present invention, there is provided a connection structure including 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, wherein the connection portion is formed of the conductive particles or a conductive material including the conductive particles and a binder resin, the conductive particles are the above-described conductive particles, and the first electrode and the second electrode are electrically connected by the conductive particles.

Advantages of the Invention

[0027] The conductive particles according to the present invention include resin particles and a conductive portion disposed outside the outer surface of the resin particles, and have the following configuration A, configuration B, or configuration C. Configuration A: It includes a magnetic body portion containing a magnetic body disposed between the resin particles and the conductive portion, and the ratio of the residual magnetization to the saturation magnetization in the conductive particles is 0.4 or less. Configuration B: The conductive portion contains a magnetic body, and the ratio of the residual magnetization to the saturation magnetization in the conductive particles is 0.4 or less. Configuration C: The resin particles contain a magnetic body. In the conductive particles according to the present invention, since the above configuration is provided, the saturation magnetization can be increased, the residual magnetization can be decreased, and when the electrodes are electrically connected, the conduction reliability can be enhanced.

Brief Description of Drawings

[0028]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0029] Hereinafter, the details of the present invention will be described.

[0030] (Conductive Particles) The conductive particles according to the present invention include resin particles and a conductive portion disposed outside the outer surface of the resin particles, and have the following configuration A, configuration B, or configuration C.

[0031] Configuration A: It includes a magnetic body part containing a magnetic body disposed between the resin particles and the conductive part, and the ratio of the residual magnetization of the conductive particles to the saturation magnetization is 0.4 or less. Configuration B: The conductive part contains a magnetic body, and the ratio of the residual magnetization of the conductive particles to the saturation magnetization is 0.4 or less. Configuration C: The resin particles contain a magnetic body.

[0032] In the conductive particles according to the present invention, since the above configuration is provided, the saturation magnetization can be increased, the residual magnetization can be decreased, and when the electrodes are electrically connected, the conduction reliability can be enhanced.

[0033] In the conductive particles according to the present invention, since the saturation magnetization can be increased, even in a highly viscous conductive material, the conductive particles contained in the conductive material can be well arranged between the upper and lower electrodes to be connected by a magnetic field.

[0034] Also, in the conductive particles according to the present invention, since the residual magnetization can be decreased, the magnetic aggregation of the conductive particles can be effectively suppressed.

[0035] Also, in the conductive particles according to the present invention, the conduction reliability can be enhanced. In the conductive particles according to the present invention, when the electrodes are electrically connected, the connection resistance between the upper and lower electrodes to be connected can be effectively decreased, and the insulation reliability between the lateral electrodes that should not be connected can be enhanced.

[0036] The conductive particles according to the present invention include at least one of the above Configuration A, the above Configuration B, and the above Configuration C. The conductive particles according to the present invention may include only the above Configuration A, may include only the above Configuration B, or may include only the above Configuration C. The conductive particles according to the present invention may include at least two of the above Configuration A, the above Configuration B, and the above Configuration C. The conductive particles according to the present invention may include the above Configuration A and the above Configuration B, may include the above Configuration B and the above Configuration C, or may include the above Configuration A and the above Configuration C. The conductive particles according to the present invention may include the above Configuration A, the above Configuration B, and the above Configuration C.

[0037] In the conductive particles including the above Configuration A or the above Configuration B, the ratio of the residual magnetization to the saturation magnetization in the conductive particles (residual magnetization / saturation magnetization) is 0.4 or less. When the above ratio (residual magnetization / saturation magnetization) exceeds 0.4, magnetic aggregation may easily occur or the conduction reliability may decrease.

[0038] In the conductive particles including the above Configuration A or the above Configuration B, the ratio of the residual magnetization to the saturation magnetization (residual magnetization / saturation magnetization) is preferably 0.3 or less, more preferably less than 0.1, and still more preferably less than 0.05. When the above ratio (residual magnetization / saturation magnetization) is at or below the above upper limit or less than the above upper limit, magnetic aggregation can be more effectively suppressed and the conduction reliability can be further enhanced. In the conductive particles including the above Configuration A or the above Configuration B, the ratio of the residual magnetization to the saturation magnetization (residual magnetization / saturation magnetization) may be 0.01 or more.

[0039] In the conductive particles having the above configuration C, the ratio of the residual magnetization to the saturation magnetization (residual magnetization / saturation magnetization) is preferably 0.4 or less, more preferably 0.3 or less, still more preferably less than 0.1, and particularly preferably less than 0.05. When the above ratio (residual magnetization / saturation magnetization) is at or below the above upper limit or less than the above upper limit, magnetic aggregation can be suppressed more effectively, and the conduction reliability can be further enhanced. In the conductive particles having the above configuration C, the ratio of the residual magnetization to the saturation magnetization (residual magnetization / saturation magnetization) may be 0.01 or more.

[0040] From the viewpoint of more effectively exerting the effects of the present invention, the residual magnetization of the above conductive particles is preferably less than 2.0 emu / g, more preferably 1.8 emu / g or less, still more preferably 1.5 emu / g or less, and particularly preferably less than 1.2 emu / g. The residual magnetization of the above conductive particles may be 0.5 emu / g or more, or may be 1.0 emu / g or more.

[0041] From the viewpoint of more effectively exerting the effects of the present invention, the saturation magnetization of the above conductive particles is preferably 15 emu / g or more, more preferably 20 emu / g or more, still more preferably 25 emu / g or more, and particularly preferably 30 emu / g or more. The saturation magnetization of the above conductive particles may be 50 emu / g or less.

[0042] The residual magnetization and saturation magnetization of the above conductive particles can be measured using a magnetic property measuring device (for example, "MPMS2" manufactured by Quantum Design Japan). Specifically, it can be measured as follows.

[0043] Weigh the conductive particles into a capsule and attach them to a sample holder. Install the sample holder in the apparatus main body, and obtain a magnetization curve by measurement under the conditions of a temperature of 25 °C (constant temperature) and a maximum applied magnetic field of 10 kOe. Determine the residual magnetization and saturation magnetization (emu / g) from the obtained magnetization curve.

[0044] The particle diameter of the above conductive particles is preferably 0.1 μm or more, more preferably 1 μm or more, preferably 1000 μm or less, more preferably 500 μm or less, even more preferably 100 μm or less, still more preferably 50 μm or less, even still more preferably 20 μm or less, and particularly preferably 10 μm or less. When the particle diameter of the above conductive particles is equal to or greater than the above lower limit and equal to or less than the above upper limit, when connecting between electrodes using the conductive particles, the contact area between the conductive particles and the electrodes becomes sufficiently large, and it becomes difficult to form aggregated conductive particles when forming the conductive portion. Also, the distance between the electrodes connected via the conductive particles does not become too large, and it becomes difficult for the conductive portion to peel off from the surface of the resin particles. Further, when the particle diameter of the above conductive particles is equal to or greater than the above lower limit and equal to or less than the above upper limit, the conductive particles can be suitably used for applications of conductive materials.

[0045] The particle diameter of the above conductive particles means the diameter when the conductive particles are spherical, and when the conductive particles have a shape other than spherical, it means the diameter when assuming a sphere equivalent to its volume.

[0046] The particle diameter of the above conductive particles is preferably the average particle diameter, and more preferably the number average particle diameter. The particle diameter of the above conductive particles is obtained by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating the average value of the particle diameters of each conductive particle, or by using a particle size distribution measuring device. In the observation with an electron microscope or an optical microscope, the particle diameter of each conductive particle is obtained as the particle diameter equivalent to a circle. In the observation with an electron microscope or an optical microscope, the average particle diameter in terms of the circle equivalent diameter of 50 arbitrary conductive particles is almost equal to the average particle diameter in terms of the sphere equivalent diameter. In a particle size distribution measuring device, the particle diameter of each conductive particle is obtained as the particle diameter in terms of the sphere equivalent diameter. It is preferable to calculate the particle diameter of the above conductive particles using a particle size distribution measuring device.

[0047] The coefficient of variation (CV value) of the particle size of the above conductive particles is preferably 20% or less, more preferably 10% or less, and still more preferably 5% or less. When the coefficient of variation of the particle size of the above conductive particles is below the above upper limit, the conduction reliability and insulation reliability between electrodes can be further enhanced more effectively. The coefficient of variation (CV value) of the particle size of the above conductive particles may be 1% or more.

[0048] The above coefficient of variation (CV value) can be measured as follows.

[0049] CV value (%) = (ρ / Dn) × 100 ρ: Standard deviation of the particle size of the conductive particles Dn: Average value of the particle size of the conductive particles

[0050] The 10% K value (compression elastic modulus when compressed by 10%) of the above conductive particles is preferably 100 N / mm 2 or more, more preferably 1000 N / mm 2 or more, preferably 25000 N / mm 2 or less, more preferably 20000 N / mm 2 or less. When the 10% K value of the above conductive particles is above the above lower limit and below the above upper limit, the connection resistance between electrodes can be further reduced more effectively, the occurrence of cracks in the conductive particles can be further suppressed more effectively, and the connection reliability between electrodes can be further enhanced more effectively.

[0051] The 30% K value (compression elastic modulus when compressed by 30%) of the above conductive particles is preferably 100 N / mm 2 or more, more preferably 1000 N / mm 2 or more, preferably 15000 N / mm 2 or less, more preferably 10000 N / mm 2 or less. When the 30% K value of the above conductive particles is above the above lower limit and below the above upper limit, the connection resistance between electrodes can be further reduced more effectively, the occurrence of cracks in the conductive particles can be further suppressed more effectively, and the connection reliability between electrodes can be further enhanced more effectively.

[0052] The ratio of the 10% K value of the conductive particles to the 30% K value of the conductive particles (10% K value of conductive particles / 30% K value of conductive particles) is preferably 1.5 or more, more preferably 1.55 or more, preferably 5 or less, and more preferably 4.5 or less. When the above ratio (10% K value of conductive particles / 30% K value of conductive particles) is above the above lower limit and below the above upper limit, the connection resistance between electrodes can be made even lower more effectively, the occurrence of cracks in the conductive particles can be suppressed more effectively, and the connection reliability between electrodes can be enhanced more effectively.

[0053] The above 10% K value and 30% K value in the conductive particles can be measured as follows.

[0054] Using a micro compression tester, compress one conductive particle under the conditions of 25 °C, a compression speed of 0.3 mN / second, and a maximum test load of 20 mN with the smooth indenter end face of a cylinder (diameter 100 μm, made of diamond). Measure the load value (N) and compression displacement (mm) at this time. From the obtained measurement values, the above compression elastic modulus (10% K value and 30% K value) can be obtained by the following formula. As the above micro compression tester, "Fisherscope H-100" manufactured by Fisher et al. is used. The above 10% K value and 30% K value in the conductive particles are preferably calculated by arithmetically averaging the 10% K value and 30% K value of 50 arbitrarily selected conductive particles.

[0055] 10% K value and 30% K value (N / mm 2 )=(3 / 2 1 / 2 )·F·S -3 / 2 ·R -1 / 2 F: Load value (N) when the conductive particle is compressed by 10% or 30% S: Compression displacement (mm) when the conductive particle is compressed by 10% or 30% R: Radius (mm) of the conductive particle

[0056] The above compression elastic modulus universally and quantitatively represents the hardness of the conductive particles. By using the above compression elastic modulus, the hardness of the conductive particles can be quantitatively and uniquely represented. Further, the above ratio (10% K value of the conductive particles / 30% K value of the conductive particles) can quantitatively and uniquely represent the physical properties of the conductive particles at the initial compression.

[0057] The shape of the above conductive particles is not particularly limited. The shape of the above conductive particles may be spherical, may be a shape other than spherical, or may be a shape such as a flat shape.

[0058] FIG. 1 is a cross-sectional view schematically showing the conductive particles according to the first embodiment of the present invention.

[0059] The conductive particle 1 shown in FIG. 1 is a conductive particle having the above configuration A. The conductive particle 1 has a resin particle 2, a conductive part 3, and a magnetic body part 4. The magnetic body part 4 contains a magnetic body. The conductive part 3 is disposed outside the outer surface of the resin particle 2. The magnetic body part 4 is disposed between the resin particle 2 and the conductive part 3. Therefore, in the conductive particle 1, the magnetic body part 4 is disposed on the outer surface of the resin particle 2, and the conductive part 3 is disposed on the outer surface of the magnetic body part 4. The conductive part 3 is a single-layer conductive layer. The magnetic body part 4 is a single-layer magnetic layer. Note that in the above conductive particle, the conductive part may be a single-layer conductive layer or a multi-layer conductive layer composed of two or more layers. Also, in the above conductive particle, the magnetic body part may be a single-layer magnetic layer or a multi-layer magnetic layer composed of two or more layers.

[0060] FIG. 2 is a cross-sectional view schematically showing the conductive particles according to the second embodiment of the present invention.

[0061] The conductive particle 1A shown in Fig. 2 is a conductive particle having the above-described Configuration B. The conductive particle 1A has a resin particle 2A and a conductive portion 3A. The conductive portion 3A contains a magnetic material. The conductive portion 3A is disposed on the outer surface of the resin particle 2A. The conductive portion 3A is a single-layer conductive layer. The conductive portion 3A is a single-layer magnetic layer. The above conductive portion may be a single-layer conductive layer or a multi-layer conductive layer composed of two or more layers.

[0062] Fig. 3 is a cross-sectional view schematically showing the conductive particle according to the third embodiment of the present invention.

[0063] The conductive particle 1B shown in Fig. 3 is a conductive particle having the above-described Configuration C. The conductive particle 1B has a resin particle 2B and a conductive portion 3B. The resin particle 2B contains a magnetic material 4B. The resin particle 2B encapsulates the magnetic material 4B. The resin particle 2B and the magnetic material 4B constitute a magnetic material-encapsulated resin particle. The conductive portion 3B is disposed on the outer surface of the resin particle 2B.

[0064] Fig. 4 is a cross-sectional view schematically showing the conductive particle according to the fourth embodiment of the present invention.

[0065] The conductive particle 1C shown in Fig. 4 is a conductive particle having the above-described Configuration C. The conductive particle 1C has a resin particle 2C, a conductive portion 3C, a plurality of core materials 5, and a plurality of insulating materials 6. The resin particle 2C contains a magnetic material 4C. The resin particle 2C encapsulates the magnetic material 4C. The resin particle 2C and the magnetic material 4C constitute a magnetic material-encapsulated resin particle. The conductive portion 3C is disposed in contact with the resin particle 2C on the outer surface of the resin particle 2C. In the above conductive particle, the above conductive portion may be a single-layer conductive layer or a multi-layer conductive layer composed of two or more layers.

[0066] The conductive particle 1C has a plurality of protrusions 1Ca on its conductive surface. The conductive portion 3C has a plurality of protrusions 3Ca on its outer surface. A plurality of core materials 5 are disposed on the surface of the resin particle 2C. The plurality of core materials 5 are embedded in the conductive portion 3C. The core material 5 is disposed inside the protrusions 1Ca and 3Ca. The conductive portion 3C covers the plurality of core materials 5. The outer surface of the conductive portion 3C is raised by the plurality of core materials 5, and the protrusions 1Ca and 3Ca are formed.

[0067] The conductive particle 1C has an insulating substance 6 disposed on the outer surface of the conductive portion 3C. At least a part of the region of the outer surface of the conductive portion 3C is covered by the insulating substance 6. The insulating substance 6 is formed of a material having insulating properties and is an insulating particle. Thus, the conductive particle according to the present invention may have an insulating substance disposed on the outer surface of the conductive portion. However, the conductive particle according to the present invention does not necessarily have an insulating substance.

[0068] FIG. 5 is a cross-sectional view showing a conductive particle according to a fifth embodiment of the present invention.

[0069] The conductive particle 1D shown in FIG. 5 is a conductive particle having the above-described configuration A. The conductive particle 1D has a resin particle 2D, a conductive portion 3D, a magnetic body portion 4D, a plurality of core materials 5, and a plurality of insulating substances 6.

[0070] The conductive portion 3D is disposed outside the outer surface of the resin particle 2D. The magnetic body portion 4D is disposed between the resin particle 2D and the conductive portion 3D. Therefore, in the conductive particle 1D, the magnetic body portion 4D is disposed on the outer surface of the resin particle 2D, and the conductive portion 3D is disposed on the outer surface of the magnetic body portion 4D. The conductive portion 3D is a single-layer conductive layer. The magnetic body portion 4D is a single-layer magnetic layer. In the above-described conductive particle, the conductive portion may be a single-layer conductive layer or a multi-layer conductive layer composed of two or more layers. Also, in the above-described conductive particle, the magnetic body portion may be a single-layer magnetic layer or a multi-layer magnetic layer composed of two or more layers.

[0071] The conductive particle 1D has a plurality of protrusions 1Da on its conductive surface. The conductive part 3D has a plurality of protrusions 3Da on its outer surface. The magnetic body part 4D has a plurality of protrusions 4Da on its outer surface. A plurality of core materials 5 are arranged on the surface of the resin particle 2D. The plurality of core materials 5 are embedded in the conductive part 3D and the magnetic body part 4D. The core material 5 is arranged inside the protrusions 1Da, 3Da, and 4Da. The magnetic body part 4D covers the plurality of core materials 5. The outer surfaces of the conductive part 3D and the magnetic body part 4D are raised by the plurality of core materials 5, and the protrusions 1Da, 3Da, and 4Da are formed.

[0072] The conductive particle 1D has an insulating substance 6 arranged on the outer surface of the conductive part 3D. At least a part of the region of the outer surface of the conductive part 3D is covered by the insulating substance 6. The insulating substance 6 is formed of a material having insulating properties and is an insulating particle. Thus, the conductive particle according to the present invention may have an insulating substance arranged on the outer surface of the conductive part. However, the conductive particle according to the present invention does not necessarily have an insulating substance.

[0073] Hereinafter, other details of the conductive particle will be described.

[0074] In this specification, “(meth)acrylate” means one or both of “acrylate” and “methacrylate”, and “(meth)acrylic” means one or both of “acrylic” and “methacrylic”.

[0075] (Resin particle) Examples of the material of the resin particle include conventionally known organic materials.

[0076] Examples of the above organic materials include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide, polyacetal, polyimide, polyamideimide, polyetheretherketone, polyethersulfone, divinylbenzene polymer, and divinylbenzene copolymer. Examples of the above divinylbenzene copolymer include divinylbenzene-styrene copolymer and divinylbenzene-(meth)acrylate copolymer.

[0077] Since the compression characteristics can be easily controlled within a suitable range, the material of the resin particles is preferably a polymer obtained by polymerizing one or more polymerizable monomers having an ethylenically unsaturated group.

[0078] The above resin particles can be obtained by polymerizing the polymerizable monomer having an ethylenically unsaturated group. The above polymerization method is not particularly limited, and examples include known methods such as radical polymerization, ionic polymerization, polycondensation (condensation polymerization, polycondensation), addition condensation, living polymerization, and living radical polymerization. Another polymerization method includes suspension polymerization in the presence of a radical polymerization initiator.

[0079] The particle diameter of the resin particles is preferably 0.1 μm or more, more preferably 0.5 μm or more, preferably 1000 μm or less, more preferably 500 μm or less, even more preferably 100 μm or less, still more preferably 20 μm or less, even still more preferably 10 μm or less, and particularly preferably 3 μm or less. When the particle diameter of the resin particles is equal to or greater than the lower limit and equal to or less than the upper limit, the contact area between the conductive particles and the electrode increases, so that the conduction reliability between the electrodes can be further enhanced, and the connection resistance between the electrodes connected via the conductive particles can be further reduced. Further, when a conductive part or a magnetic body part is formed on the surface of the resin particles by electroless plating, it is possible to make it difficult to form aggregated conductive particles. When the particle diameter of the resin particles is equal to or less than the upper limit, the conductive particles are easily compressed sufficiently, the connection resistance between the electrodes can be further reduced, and the distance between the electrodes can be further reduced.

[0080] The particle diameter of the resin particles means the diameter when the resin particles are spherical, and when the resin particles are in a shape other than spherical, it means the diameter when assuming a true sphere equivalent to its volume.

[0081] The particle diameter of the resin particles is preferably the average particle diameter, and more preferably the number average particle diameter. The particle diameter of the resin particles is obtained by observing 50 arbitrary resin particles with an electron microscope or an optical microscope and calculating the average value of the particle diameters of each resin particle, or by using a particle size distribution measuring device. In the observation with an electron microscope or an optical microscope, the particle diameter of each resin particle is obtained as the particle diameter equivalent to a circle. In the observation with an electron microscope or an optical microscope, the average particle diameter in terms of the circle equivalent diameter of any 50 resin particles is almost equal to the average particle diameter in terms of the sphere equivalent diameter. In a particle size distribution measuring device, the particle diameter of each resin particle is obtained as the particle diameter in terms of the sphere equivalent diameter. The particle diameter of the resin particles is preferably calculated using a particle size distribution measuring device. When measuring the particle diameter of the resin particles in the conductive particles, for example, it can be measured as follows.

[0082] Add and disperse in "Technovit 4000" manufactured by Kulzer so that the content of the conductive particles becomes 30% by weight to produce an embedded resin body for inspection containing the conductive particles. Using an ion milling device ("IM4000" manufactured by Hitachi High-Technologies Corporation), cut out a cross-section of the conductive particles so as to pass through the vicinity of the center of the resin particles in the conductive particles dispersed in the above-mentioned embedded resin body for inspection. Then, using a field emission scanning electron microscope (FE-SEM), set the image magnification to 25,000 times, randomly select 50 conductive particles, and observe the resin particles in each conductive particle. Measure the particle diameters of the resin particles in each conductive particle, and calculate their arithmetic mean as the particle diameter of the resin particles.

[0083] The coefficient of variation (CV value) of the particle diameter of the above resin particles is preferably 20% or less, more preferably 10% or less, and still more preferably 5% or less. When the coefficient of variation of the particle diameter of the above resin particles is below the above upper limit, the conduction reliability and insulation reliability between electrodes can be enhanced more effectively. The coefficient of variation (CV value) of the particle diameter of the above resin particles may be 1% or more.

[0084] The above coefficient of variation (CV value) can be measured as follows.

[0085] CV value (%) = (ρ / Dn) × 100 ρ: Standard deviation of the particle diameter of the resin particles Dn: Average value of the particle diameter of the resin particles

[0086] (Conductive part and magnetic body) The above conductive particles are provided with a conductive part arranged outside the outer surface of the above resin particles. Further, the above conductive particles are provided with a magnetic body part containing a magnetic body arranged between the above resin particles and the above conductive part (Configuration A), the above conductive part contains a magnetic body (Configuration B), or the above resin particles contain a magnetic body (Configuration C).

[0087] In addition, when the conductive particles include the above-described Configuration A or the above-described Configuration C, the conductive portion may contain a magnetic material. When the conductive particles include the above-described Configuration A, it is preferable that the conductive portion contains a magnetic material. When the conductive particles include the above-described Configuration C, it is preferable that the conductive portion contains a magnetic material. That is, the conductive particles preferably include the above-described Configuration A and the above-described Configuration B, and preferably include the above-described Configuration B and the above-described Configuration C.

[0088] When the conductive particles include the above-described Configuration A and the above-described Configuration B, the magnetic material contained in the magnetic body portion and the magnetic material contained in the conductive portion may be the same or different.

[0089] When the conductive particles include the above-described Configuration B and the above-described Configuration C, the magnetic material contained in the resin particles and the magnetic material contained in the conductive portion may be the same or different.

[0090] The conductive portion preferably contains a metal. Further, the conductive portion may contain a substance other than the metal. Hereinafter, the metal contained in the conductive portion may be referred to as "the metal constituting the conductive portion" for convenience. Also, "the metal constituting the conductive portion" shall include a compound of the metal, for example, an oxide of the metal. The metal constituting the conductive portion is not particularly limited, and examples thereof include gold, silver, palladium, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, thallium, germanium, cadmium, silicon, tungsten, molybdenum, and alloys thereof. Also, examples of the metal constituting the conductive portion include indium tin oxide (ITO) and solder. Only one kind of the metal constituting the conductive portion may be used, or two or more kinds may be used in combination.

[0091] From the viewpoint of more effectively reducing the connection resistance between the electrodes, the conductive portion preferably contains nickel, gold, palladium, silver, or copper, more preferably contains nickel, gold, or palladium, and particularly preferably contains nickel.

[0092] The nickel content in 100% by weight of the conductive part containing nickel is preferably 10% by weight or more, more preferably 50% by weight or more, even more preferably 60% by weight or more, still more preferably 70% by weight or more, and particularly preferably 90% by weight or more. The nickel content in 100% by weight of the conductive part containing nickel may be 97% by weight or more, may be 97.5% by weight or more, may be 98% by weight or more, or may be 100% by weight.

[0093] Note that hydroxyl groups often exist on the surface of the conductive part due to oxidation. Generally, hydroxyl groups exist on the surface of the conductive part formed of nickel due to oxidation. An insulating substance can be disposed on the surface of the conductive part (the surface of the conductive particles) having such hydroxyl groups via chemical bonds.

[0094] The above conductive part may be formed by one layer. The above conductive part may be formed by a plurality of layers. That is, the above conductive part may have a laminated structure of two or more layers. When the above conductive part is formed by a plurality of layers, the metal constituting the outermost layer is preferably gold, nickel, palladium, copper, or an alloy containing tin and silver, and more preferably gold. When the metal constituting the outermost layer is these preferred metals, the connection resistance between the electrodes becomes even lower. Also, when the metal constituting the outermost layer is gold, the corrosion resistance becomes even higher. The metal constituting the outermost layer may be nickel.

[0095] The thickness of the above conductive part is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 10 μm or less, more preferably 1 μm or less, and still more preferably 0.3 μm or less. When the thickness of the above conductive part is within the above lower limit and the above upper limit, sufficient conductivity can be obtained, and the conductive particles do not become too hard, and the conductive particles can be sufficiently deformed when connecting the electrodes.

[0096] When the above conductive part is formed of a plurality of layers, the thickness of the outermost conductive part is preferably 0.001 μm or more, more preferably 0.01 μm or more, preferably 0.5 μm or less, and more preferably 0.1 μm or less. When the thickness of the outermost conductive part is equal to or more than the above lower limit and equal to or less than the above upper limit, the outermost conductive part becomes uniform, the corrosion resistance becomes sufficiently high, and the connection resistance between electrodes can be made sufficiently low.

[0097] The thickness of the above conductive part can be measured, for example, by observing the cross section of the conductive particles using a transmission electron microscope (TEM).

[0098] Magnetic material: The above magnetic material is preferably a metal or a metal oxide, and more preferably a ferromagnetic or paramagnetic material. Only one kind of the above magnetic material may be used, or two or more kinds may be used in combination.

[0099] Examples of the above magnetic material include iron, cobalt, nickel, ruthenium, lanthanoid, and ferrite. Examples of the above ferrite include magnetite (γFe2O3) and a compound represented by MFe2O4 (in MFe2O4, M is Co, Ni, Mn, Zn, Mg, Cu, Fe, Li 0.5 Fe 0.5 etc.). The above magnetic material may be an alloy. Examples of the above alloy include nickel-cobalt alloy, cobalt-tungsten alloy, iron-platinum alloy, and iron-cobalt alloy. Further, the above metal may be a metal ion.

[0100] From the viewpoint of further enhancing the magnetic aggregation property, the above magnetic material preferably contains iron, cobalt, ferrite, nickel or an alloy thereof, more preferably contains iron, cobalt, or ferrite, and still more preferably contains iron, cobalt, or magnetite (Fe3O4).

[0101] In the conductive particles including the above-described Configuration A, in 100% by volume in total of the content of the resin particles and the content of the magnetic body part, the content of the magnetic body included in the magnetic body part is defined as content (A1). The content (A1) is preferably 3% by volume or more, more preferably 5% by volume or more, still more preferably 10% by volume or more, further preferably 15% by volume or more, still further preferably 18% by volume or more, particularly preferably 20% by volume or more, preferably 45% by volume or less, more preferably 40% by volume or less, still more preferably 35% by volume or less. When the content (A1) is not less than the above lower limit and not more than the above upper limit, the magnetic collection property can be further enhanced.

[0102] In the conductive particles including the above-described Configuration A, in 100% by weight in total of the content of the resin particles and the content of the magnetic body part, the content of the magnetic body included in the magnetic body part is defined as content (A2). The content (A2) is preferably 10% by weight or more, more preferably 15% by weight or more, still more preferably 30% by weight or more, further preferably 40% by weight or more, still further preferably 45% by weight or more, particularly preferably 50% by weight or more, preferably 80% by weight or less, more preferably 75% by weight or less, still more preferably 70% by weight or less. When the content (A2) is not less than the above lower limit and not more than the above upper limit, the magnetic collection property can be further enhanced.

[0103] In the conductive particles including the above-described Configuration A, in 100% by volume of the conductive particles, the content of the magnetic body included in the conductive particles is defined as content (A3). Therefore, in the content (A3), when the conductive particles contain a magnetic body in a part other than the magnetic body part (for example, a conductive part or resin particles), it is the content of the magnetic body including these as well. The content (A3) is preferably 2% by volume or more, more preferably 5% by volume or more, still more preferably 10% by volume or more, further preferably 30% by volume or more, still further preferably 35% by volume or more, particularly preferably 40% by volume or more, preferably 80% by volume or less, more preferably 75% by volume or less, still more preferably 70% by volume or less. When the content (A3) is not less than the above lower limit and not more than the above upper limit, the magnetic collection property can be further enhanced.

[0104] In the conductive particles including the above-described configuration A, the content of the magnetic material contained in the conductive particles is defined as content (A4) in 100% by weight of the conductive particles. Therefore, in the case where the content (A4) is such that the conductive particles contain a magnetic material in a portion other than the magnetic body portion (for example, a conductive portion or resin particles), it is the content of the magnetic material including these as well. The content (A4) is preferably 3% by weight or more, more preferably 5% by weight or more, even more preferably 10% by weight or more, still more preferably 50% by weight or more, even still more preferably 70% by weight or more, particularly preferably 75% by weight or more, most preferably 80% by weight or more, preferably 97% by weight or less, more preferably 95% by weight or less. When the content (A4) is not less than the above lower limit and not more than the above upper limit, the magnetic collection property can be further enhanced.

[0105] In the conductive particles including the above-described configuration B, the content of the magnetic material contained in the conductive portion is defined as content (B1) in 100% by volume of the total of the content of the resin particles and the content of the conductive portion. The content (B1) is preferably 3% by volume or more, more preferably 5% by volume or more, still more preferably 7% by volume or more, particularly preferably 10% by volume or more, preferably 60% by volume or less, more preferably 55% by volume or less, still more preferably 50% by volume or less. When the content (B1) is not less than the above lower limit and not more than the above upper limit, the magnetic collection property can be further enhanced.

[0106] In the conductive particles including the above-described configuration B, the content of the magnetic material contained in the conductive portion is defined as content (B2) in 100% by weight of the total of the content of the resin particles and the content of the conductive portion. The content (B2) is preferably 10% by weight or more, more preferably 15% by weight or more, still more preferably 20% by weight or more, preferably 98% by weight or less, more preferably 95% by weight or less, still more preferably 90% by weight or less. When the content (B2) is not less than the above lower limit and not more than the above upper limit, the magnetic collection property can be further enhanced.

[0107] In the conductive particles including the above-described configuration B, the content of the magnetic material contained in the conductive particles is defined as content (B3) in 100% by volume of the conductive particles. Therefore, in the case where the conductive particles contain a magnetic material in a portion other than the conductive portion (for example, a magnetic body portion or resin particles), the content (B3) is the content of the magnetic material including these. The content (B3) is preferably 2% by volume or more, more preferably 5% by volume or more, still more preferably 10% by volume or more, further preferably 15% by volume or more, still further preferably 18% by volume or more, particularly preferably 20% by volume or more, preferably 95% by volume or less, more preferably 93% by volume or less, and still more preferably 90% by volume or less. When the content (B3) is equal to or more than the lower limit and equal to or less than the upper limit, the magnetic collectability can be further enhanced.

[0108] In the conductive particles including the above-described configuration B, the content of the magnetic material contained in the conductive particles is defined as content (B4) in 100% by weight of the conductive particles. Therefore, in the case where the conductive particles contain a magnetic material in a portion other than the conductive portion (for example, a magnetic body portion or resin particles), the content (B4) is the content of the magnetic material including these. The content (B4) is preferably 3% by weight or more, more preferably 7% by weight or more, still more preferably 10% by weight or more, further preferably 30% by weight or more, still further preferably 45% by weight or more, particularly preferably 50% by weight or more, and most preferably 60% by weight or more. The content (B4) is preferably 99% by weight or less, more preferably 98% by weight or less, and still more preferably 97% by weight or less. When the content (B4) is equal to or more than the lower limit and equal to or less than the upper limit, the magnetic collectability can be further enhanced.

[0109] In the conductive particles including the above configuration C, the content of the magnetic material contained in the resin particles is defined as content (C1) in 100% by volume of the resin particle content. The content (C1) is preferably 3% by volume or more, more preferably 5% by volume or more, still more preferably 10% by volume or more, further preferably 15% by volume or more, still further preferably 18% by volume or more, particularly preferably 20% by volume or more, preferably 85% by volume or less, more preferably 80% by volume or less. When the content (C1) is equal to or higher than the lower limit and equal to or lower than the upper limit, the magnetic collectability can be further enhanced.

[0110] In the conductive particles including the above configuration C, the content of the magnetic material contained in the resin particles is defined as content (C2) in 100% by weight of the resin particle content. The content (C2) is preferably 10% by weight or more, more preferably 15% by weight or more, still more preferably 20% by weight or more, further preferably 40% by weight or more, still further preferably 45% by weight or more, particularly preferably 50% by weight or more, preferably 99% by weight or less, more preferably 97% by weight or less, further preferably 95% by weight or less. When the content (C2) is equal to or higher than the lower limit and equal to or lower than the upper limit, the magnetic collectability can be further enhanced.

[0111] In the conductive particles including the above configuration C, the content of the magnetic material contained in the conductive particles is defined as content (C3) in 100% by volume of the conductive particle content. Therefore, in the content (C3), when the conductive particles contain a magnetic material in a portion other than the resin particles (for example, a conductive portion or a magnetic material portion), it is the content of the magnetic material including these as well. The content (C3) is preferably 3% by volume or more, more preferably 7% by volume or more, still more preferably 10% by volume or more, further preferably 15% by volume or more, still further preferably 18% by volume or more, particularly preferably 20% by volume or more, preferably 95% by volume or less, more preferably 90% by volume or less, further preferably 88% by volume or less. When the content (C3) is equal to or higher than the lower limit and equal to or lower than the upper limit, the magnetic collectability can be further enhanced.

[0112] In the conductive particles including the above-described structure C, the content of the magnetic material contained in the conductive particles is defined as content (C4) in 100% by weight of the conductive particles. Therefore, in the case where the content (C4) is such that the conductive particles contain a magnetic material in a portion other than the resin particles (for example, a conductive portion or a magnetic material portion), it is the content of the magnetic material including these as well. The content (C4) is preferably 3% by weight or more, more preferably 5% by weight or more, still more preferably 10% by weight or more, further preferably 30% by weight or more, even still more preferably 60% by weight or more, particularly preferably 65% by weight or more, most preferably 70% by weight or more, preferably 99% by weight or less, and more preferably 97% by weight or less. When the content (C4) is equal to or greater than the above lower limit and equal to or less than the above upper limit, the magnetic collection property can be further enhanced.

[0113] In the conductive particles, the content of the magnetic material contained in the conductive particles is defined as content (D) in 100% by volume of the conductive particles. The content (D) is preferably 3% by volume or more, more preferably 5% by volume or more, still more preferably 10% by volume or more, further preferably 25% by volume or more, particularly preferably 50% by volume or more, and preferably 85% by volume or less. When the content (D) is equal to or greater than the above lower limit and equal to or less than the above upper limit, the magnetic collection property can be further enhanced.

[0114] In the conductive particles, the content of the magnetic material contained in the conductive particles is defined as content (E) in 100% by weight of the conductive particles. The content (E) is preferably 5% by weight or more, more preferably 10% by weight or more, still more preferably 15% by weight or more, further preferably 25% by weight or more, particularly preferably 40% by weight or more, preferably 99% by weight or less, and more preferably 97% by weight or less. When the content (E) is equal to or greater than the above lower limit and equal to or less than the above upper limit, the magnetic collection property can be further enhanced.

[0115] The above contents (A1) to (A4), (B1) to (B4), (C1) to (C4), (D), and (E) can be measured by ICP emission spectrometry. Specifically, they can be measured as follows.

[0116] Using hydrochloric acid or the like, the conductive particles are completely dissolved, and the amount of metal ions contained in the conductive particles is quantified. From the quantified amount of metal ions, the content (weight %) of the magnetic material present in the conductive particles is calculated. Also, from the density of the magnetic material, the volume of the magnetic material can be calculated. The volume of the conductive particles can be calculated from the radius of the conductive particles measured by observing the cross-section of the conductive particles, and the content (volume % and weight %) of the magnetic material can be calculated.

[0117] In the conductive particles having the above Configuration A, the magnetic body part may be a continuous layer or an agglomerated layer that is an aggregate of magnetic fine particles. In the conductive particles having the above Configuration A, it is preferable that the magnetic body part is an agglomerated layer that is an aggregate of magnetic fine particles.

[0118] In the conductive particles having the above Configuration A, the primary average particle diameter of the magnetic fine particles constituting the agglomerated layer that is the aggregate of the magnetic fine particles is preferably 1 nm or more, more preferably 3 nm or more, still more preferably 5 nm or more, preferably 500 nm or less, more preferably 100 nm or less, still more preferably 50 nm or less, and particularly preferably 20 nm or less.

[0119] In the conductive particles having the above Configuration C, the primary average particle diameter of the magnetic material is preferably 1 nm or more, more preferably 3 nm or more, still more preferably 5 nm or more, preferably 500 nm or less, more preferably 100 nm or less, still more preferably 50 nm or less, and particularly preferably 20 nm or less.

[0120] The primary average particle diameter of the magnetic fine particles can be measured, for example, by observing using a transmission electron microscope (TEM).

[0121] When the conductive particles having the above-described Configuration A contain a magnetic material in the above-described conductive portion, the content of the conductive portion contained in the conductive particles in 100% by weight of the conductive particles is preferably 15% by weight or more, more preferably 30% by weight or more, still more preferably 40% by weight or more, preferably 95% by weight or less, more preferably 85% by weight or less, still more preferably 75% by weight or less. In particular, when the content of the conductive portion contained in the conductive particles is not less than the above lower limit and not more than the above upper limit, and the primary average particle diameter of the magnetic fine particles constituting the aggregated layer is not less than the above lower limit and not more than the above upper limit, it is easy to adjust the ratio of the residual magnetization to the saturation magnetization to 0.4 or less. That is, the conductive particles having the above-described Configuration A and the above-described Configuration B can be obtained favorably.

[0122] In the conductive particles having the above-described Configuration B, the content of the conductive portion contained in the conductive particles in 100% by weight of the conductive particles is preferably 15% by weight or more, more preferably 30% by weight or more, still more preferably 40% by weight or more, preferably 95% by weight or less, more preferably 85% by weight or less, still more preferably 75% by weight or less. When the content of the conductive portion contained in the conductive particles is not less than the above lower limit and not more than the above upper limit, it is easy to adjust the ratio of the residual magnetization to the saturation magnetization to 0.4 or less. That is, the conductive particles having the above-described Configuration B can be obtained favorably.

[0123] When the conductive particles having the above-described Configuration C contain a magnetic material in the above-described conductive portion, the content of the conductive portion contained in the conductive particles in 100% by weight of the conductive particles is preferably 15% by weight or more, more preferably 30% by weight or more, still more preferably 40% by weight or more, preferably 95% by weight or less, more preferably 85% by weight or less, still more preferably 75% by weight or less. In particular, when the content of the conductive portion contained in the conductive particles is not less than the above lower limit and not more than the above upper limit, and the primary average particle diameter of the magnetic material is not less than the above lower limit and not more than the above upper limit, it is easy to adjust the ratio of the residual magnetization to the saturation magnetization to 0.4 or less. That is, the conductive particles having the above-described Configuration C and the above-described Configuration B can be obtained favorably.

[0124] In 100% by weight of the above conductive particles, the content of the conductive portion contained in the conductive particles can be measured by energy dispersive X-ray analysis (EDX) using a field emission transmission electron microscope ("JEM-2010FEF" manufactured by JEOL Ltd.) and ICP emission spectrometry. Specifically, it can be measured as follows.

[0125] Add and disperse the conductive particles to "Technovit 4000" manufactured by Kulzer so that the content is 30% by weight to produce an embedded resin body for inspection containing the conductive particles. Cut out a cross-section of the conductive particles using an ion milling device ("IM4000" manufactured by Hitachi High-Technologies Corporation) so as to pass through the vicinity of the center of the dispersed conductive particles in the above inspection embedded resin body. The distribution and type of metals contained in the conductive portion in the conductive particles can be measured by energy dispersive X-ray analysis (EDX) using a field emission transmission electron microscope ("JEM-2010FEF" manufactured by JEOL Ltd.).

[0126] Completely dissolve the conductive particles using hydrochloric acid or the like, and quantify the amount of metal ions contained in the conductive particles. From the quantified amount of metal ions, calculate the content (% by weight) of the conductive portion present in the conductive particles. Also, the volume of the conductive portion can be calculated from the density of the metal contained in the conductive portion. The volume of the conductive particles can be calculated from the radius of the conductive particles measured by observing the cross-section of the conductive particles, and the content (% by volume and % by weight) of the conductive portion can be calculated.

[0127] In the conductive particles having the above Configuration A, the thickness of the magnetic body portion is preferably 0.05 μm or more, more preferably 0.1 μm or more, preferably 0.5 μm or less, more preferably 0.3 μm or less, and still more preferably 0.2 μm or less. When the thickness of the magnetic body portion is equal to or greater than the above lower limit and equal to or less than the above upper limit, sufficient magnetic performance can be obtained, and the effects of the present invention can be more effectively exerted.

[0128] The thickness of the magnetic body portion can be measured, for example, by observing the cross-section of the conductive particles using a transmission electron microscope (TEM).

[0129] In the conductive particles including the above-described Configuration A or the above-described Configuration B, the method for forming the conductive portion or the magnetic body portion on the surface of the resin particles is not particularly limited. Examples of the method for forming the conductive portion or the magnetic body portion include a method by electroless plating, a method by electroplating, a method by physical collision, a method by mechanochemical reaction, a method by physical vapor deposition or physical adsorption, and a method of coating the surface of the resin particles with a paste containing metal powder or a metal powder and a binder. The method for forming the conductive portion or the magnetic body portion is preferably a method by electroless plating, electroplating or physical collision. Examples of the method by physical vapor deposition include methods such as vacuum evaporation, ion plating and ion sputtering. In addition, in the method by physical collision, for example, a Seater Composer (manufactured by Tokuju Kousakusho Co., Ltd.) is used.

[0130] In the conductive particles including the above-described Configuration C, the magnetic body may be dispersed and present inside the resin particles or may be present in a layered manner. From the viewpoint of reducing the residual magnetization, in the conductive particles including the above-described Configuration C, the magnetic body is preferably dispersed and present inside the resin particles.

[0131] For example, by mixing the resin particles having a porous structure and the magnetic body and introducing the magnetic body into the resin particles, resin particles in which the magnetic body is dispersed and present inside can be obtained. Further, for example, by mixing the resin particles having a solid structure and the magnetic body, coating the outer surface of the resin particles with the magnetic body, and then coating the outer surface of the magnetic body with resin, resin particles in which the magnetic body is present in a layered manner can be obtained.

[0132] (Core material) The above conductive particles preferably have protrusions on the outer surface of the above conductive portion. The above conductive particles preferably have protrusions on the conductive surface. It is preferable that there are a plurality of the above protrusions. The above conductive particles preferably have a plurality of the above protrusions. An oxide film is often formed on the surface of the electrode connected by the conductive particles. When using conductive particles having protrusions on the surface of the conductive portion, by disposing the conductive particles between the electrodes and pressing them, the above oxide film can be effectively removed by the protrusions. For this reason, the electrode and the conductive portion come into contact more reliably, and the connection resistance between the electrodes becomes even lower. Further, when the conductive particles include an insulating substance, or when the conductive particles are dispersed in a binder resin and used as a conductive material, the insulating substance or the binder resin between the conductive particles and the electrode can be more effectively removed by the protrusions of the conductive particles. For this reason, the connection resistance between the electrodes can be made even lower.

[0133] Examples of the method for forming the above protrusions include a method of forming a conductive portion by electroless plating after attaching a core material to the surface of metal particles, and a method of forming a conductive portion by electroless plating on the surface of metal particles, then attaching a core material, and further forming a conductive portion by electroless plating. Also, in order to form the above protrusions, it is not necessary to use the above core material.

[0134] Examples of other methods for forming the above protrusions include a method of adding a core material in an intermediate stage of forming a conductive portion on the surface of metal particles. Also, in order to form protrusions, after forming a conductive portion on metal particles by electroless plating without using the above core material, a plating may be deposited in a protrusion shape on the surface of the conductive portion, and further a method of forming a conductive portion by electroless plating may be used.

[0135] As a method of attaching a core material to the surface of metal particles, there are a method of adding the core material to a dispersion of metal particles and accumulating and attaching the core material to the surface of the metal particles by van der Waals forces, and a method of adding the core material to a container containing the metal particles and attaching the core material to the surface of the metal particles by a mechanical action such as rotation of the container. From the viewpoint of controlling the amount of the core material to be attached, the method of attaching the core material to the surface of the metal particles is preferably a method of accumulating and attaching the core material to the surface of the metal particles in the dispersion.

[0136] Examples of the material constituting the core material include a conductive material and a non-conductive material. Examples of the conductive material include metals, metal oxides, conductive non-metals such as graphite, and conductive polymers. Examples of the conductive polymer include polyacetylene. Examples of the non-conductive material include silica, alumina, and zirconia. From the viewpoint of more effectively eliminating the oxide film, it is preferable that the core material is hard. From the viewpoint of more effectively reducing the connection resistance between electrodes, it is preferable that the core material is a metal.

[0137] The metal is not particularly limited. Examples of the metal include metals such as gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium, and cadmium, and alloys composed of two or more metals such as tin-lead alloy, tin-copper alloy, tin-silver alloy, tin-lead-silver alloy, and tungsten carbide. From the viewpoint of more effectively reducing the connection resistance between electrodes, it is preferable that the metal is nickel, copper, silver, or gold. The metal may be the same as or different from the metal constituting the conductive portion (conductive layer). The metal may be the same as or different from the metal constituting the metal particles.

[0138] The shape of the core material is not particularly limited. The shape of the core material is preferably a lump. Examples of the core material include a particulate lump, an agglomerate in which a plurality of fine particles are aggregated, and an amorphous lump.

[0139] The particle diameter of the above core material is preferably 0.001 μm or more, more preferably 0.05 μm or more, preferably 0.9 μm or less, and more preferably 0.2 μm or less. When the particle diameter of the above core material is equal to or greater than the above lower limit and equal to or less than the above upper limit, the connection resistance between electrodes can be made even lower more effectively.

[0140] The particle diameter of the above core material is preferably the average particle diameter, and more preferably the number average particle diameter. The particle diameter of the core material can be obtained by observing 50 arbitrary core materials with an electron microscope or an optical microscope and calculating the average value of the particle diameters of each core material, or by using a particle size distribution measuring device. In the observation with an electron microscope or an optical microscope, the particle diameter of each core material is determined as the particle diameter in terms of the equivalent circle diameter. In the observation with an electron microscope or an optical microscope, the average particle diameter in terms of the equivalent circle diameter of 50 arbitrary core materials is almost equal to the average particle diameter in terms of the equivalent sphere diameter. In the particle size distribution measuring device, the particle diameter of each core material is determined as the particle diameter in terms of the equivalent sphere diameter. The average particle diameter of the above core material is preferably calculated using a particle size distribution measuring device.

[0141] The number of the above protrusions per one of the above conductive particles is preferably 3 or more, and more preferably 5 or more. The upper limit of the number of the above protrusions is not particularly limited. The upper limit of the number of the above protrusions can be appropriately selected in consideration of the particle diameter of the conductive particles and the like. When the number of the above protrusions is equal to or greater than the above lower limit, the connection resistance between electrodes can be made even lower more effectively.

[0142] The number of the above protrusions can be calculated by observing arbitrary conductive particles with an electron microscope or an optical microscope. The number of the above protrusions is preferably obtained by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating the average value of the number of protrusions in each conductive particle.

[0143] The height of the protrusion is preferably 0.001 μm or more, more preferably 0.05 μm or more, preferably 0.9 μm or less, and more preferably 0.2 μm or less. When the height of the protrusion is equal to or greater than the lower limit and equal to or less than the upper limit, the connection resistance between the electrodes can be made even lower more effectively.

[0144] The height of the protrusion can be calculated by observing the protrusions on any conductive particles with an electron microscope or an optical microscope. Preferably, the height of the protrusion is calculated as the average value of the heights of all the protrusions per conductive particle as the height of the protrusion of one conductive particle. Preferably, the height of the protrusion is determined by calculating the average value of the heights of the protrusions of each of 50 arbitrary conductive particles.

[0145] (Insulating substance) The conductive particles preferably include an insulating substance disposed on the outer surface of the conductive portion. In this case, when the conductive particles are used for connection between the electrodes, short circuits between adjacent electrodes can be more effectively prevented. Specifically, when a plurality of conductive particles come into contact, since an insulating substance exists between the plurality of electrodes, short circuits between electrodes adjacent in the lateral direction rather than between the upper and lower electrodes can be prevented. Note that when connecting the electrodes, by pressing the conductive particles with two electrodes, the insulating substance between the conductive portion of the conductive particle and the electrode can be easily removed. Furthermore, in the case of a conductive particle having a protrusion on the outer surface of the conductive portion, the insulating substance between the conductive portion of the conductive particle and the electrode can be removed even more easily.

[0146] Since the insulating substance can be removed even more easily during crimping between the electrodes, the insulating substance is preferably insulating particles.

[0147] Examples of the material of the insulating substance include the resins and inorganic substances described above. The material of the insulating substance is preferably the resin. Only one type of the material of the insulating substance may be used, or two or more types may be used in combination.

[0148] Examples of the inorganic substance include silica, alumina, barium titanate, zirconia, carbon black, silicate glass, borosilicate glass, lead glass, soda-lime glass, and aluminosilicate glass.

[0149] Examples of other materials for the insulating substance include polyolefin compounds, (meth)acrylate polymers, (meth)acrylate copolymers, block polymers, thermoplastic resins, crosslinked products of thermoplastic resins, thermosetting resins, and water-soluble resins.

[0150] 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 polystyryl (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, and hydrogenated products thereof. Examples of the thermoplastic resin include vinyl polymers and vinyl copolymers. Examples of the thermosetting resin include epoxy resins, phenol resins, and melamine resins. Examples of the crosslinked product of the thermoplastic resin include the introduction of polyethylene glycol methacrylate, alkoxylated trimethylolpropane methacrylate, alkoxylated pentaerythritol methacrylate, etc. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinyl pyrrolidone, polyethylene oxide, and methyl cellulose. Further, a chain transfer agent may be used to adjust the degree of polymerization. Examples of the chain transfer agent include thiol and carbon tetrachloride.

[0151] As methods for disposing the insulating substance on the surface of the conductive portion, chemical methods, physical or mechanical methods, etc. can be mentioned. Examples of the chemical methods include interfacial polymerization method, suspension polymerization method in the presence of particles, and emulsion polymerization method. Examples of the physical or mechanical methods include spray drying, hybridization, electrostatic deposition method, spraying method, dipping, and method by vacuum evaporation. From the viewpoint of further effectively enhancing insulation reliability and conduction reliability when electrically connecting between electrodes, the method for disposing the insulating substance on the surface of the conductive portion is preferably a physical method.

[0152] The outer surface of the conductive portion and the outer surface of the insulating substance may each be coated with a compound having a reactive functional group. The outer surface of the conductive portion and the outer surface of the insulating substance do not necessarily have to be directly chemically bonded, and may be indirectly chemically bonded by a compound having a reactive functional group. After introducing a carboxyl group onto the outer surface of the conductive portion, the carboxyl group may be chemically bonded to a functional group on the outer surface of the insulating substance via a polyelectrolyte such as polyethyleneimine.

[0153] When the insulating substance is insulating particles, the particle diameter of the insulating particles can be appropriately selected according to the particle diameter of the conductive particles, the use of the conductive particles, etc. The particle diameter of the insulating particles is preferably 10 nm or more, more preferably 100 nm or more, still more preferably 300 nm or more, particularly preferably 500 nm or more, and preferably 4000 nm or less, more preferably 2000 nm or less, still more preferably 1500 nm or less, particularly preferably 1000 nm or less. When the particle diameter of the insulating particles is at least the above lower limit, when the conductive particles are dispersed in the binder resin, it becomes difficult for the conductive portions in the plurality of conductive particles to contact each other. When the particle diameter of the insulating particles is at most the above upper limit, when connecting between electrodes, it is not necessary to increase the pressure too much or heat to a high temperature in order to remove the insulating particles between the electrode and the conductive particles.

[0154] The particle size of the insulating particles is preferably the average particle size, and preferably the number average particle size. The particle size of the insulating particles is obtained by observing 50 arbitrary insulating particles with an electron microscope or an optical microscope and calculating the average value of the particle sizes of each insulating particle, or by using a particle size distribution measuring device. In the observation with an electron microscope or an optical microscope, the particle size of each insulating particle is determined as the particle size in terms of the equivalent circle diameter. In the observation with an electron microscope or an optical microscope, the average particle size in terms of the equivalent circle diameter of 50 arbitrary insulating particles is almost equal to the average particle size in terms of the equivalent sphere diameter. In the particle size distribution measuring device, the particle size of each insulating particle is determined as the particle size in terms of the equivalent sphere diameter. The average particle size of the insulating particles is preferably calculated using a particle size distribution measuring device. When measuring the particle size of the insulating particles in the conductive particles, for example, it can be measured as follows.

[0155] Add and disperse the conductive particles into "Technovit 4000" manufactured by Kulzer so that the content of the conductive particles becomes 30% by weight to produce an embedded resin body for inspection containing the conductive particles. Using an ion milling device ("IM4000" manufactured by Hitachi High-Technologies Corporation), cut out the cross-section of the conductive particles so as to pass through the vicinity of the center of the insulating particles in the conductive particles dispersed in the above-mentioned embedded resin body for inspection. Then, using a field emission scanning electron microscope (FE-SEM), set the image magnification to 50,000 times, randomly select 50 conductive particles, and observe the insulating particles of each conductive particle. Measure the particle sizes of the insulating particles in each conductive particle, and calculate their arithmetic mean as the particle size of the insulating particles.

[0156] The ratio of the particle size of the conductive particles to the particle size of the insulating particles (particle size of conductive particles / particle size of insulating particles) is preferably 4 or more, more preferably 8 or more, preferably 200 or less, and more preferably 100 or less. When the above ratio (particle size of conductive particles / particle size of insulating particles) is above the above lower limit and below the above upper limit, when the electrodes are electrically connected, the insulation reliability and the conduction reliability can be enhanced more effectively.

[0157] (Conductive material) The conductive material according to the present invention includes the above-described conductive particles and a binder resin. The conductive particles are preferably dispersed in the binder resin and used as a conductive material. The conductive material is preferably an anisotropic conductive material. The conductive material is preferably used suitably for electrical connection of electrodes. The conductive material is preferably a circuit connection material.

[0158] The binder resin is not particularly limited. As the binder resin, a known insulating resin is used. The binder resin preferably contains a thermoplastic component (thermoplastic compound) or a curable component, and more preferably contains a curable component. Examples of the curable component include a photocurable component and a thermosetting component. The photocurable component preferably contains a photocurable compound and a photoinitiator. The thermosetting component preferably contains a thermosetting compound and a curing agent. Examples of the binder resin include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, and elastomers. Only one type of the binder resin may be used, or two or more types may be used in combination.

[0159] Examples of the vinyl resin include vinyl acetate resin, acrylic resin, and styrene resin. Examples of the thermoplastic resin include polyolefin resin, ethylene-vinyl acetate copolymer, and polyamide resin. Examples of the curable resin include epoxy resin, urethane resin, polyimide resin, and unsaturated polyester resin. Note that the curable resin may be a room temperature curable resin, a thermosetting resin, a photocurable resin, or a moisture curable resin. The curable resin may 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 product of styrene-butadiene-styrene block copolymer, and hydrogenated product of styrene-isoprene-styrene block copolymer. Examples of the elastomer include styrene-butadiene copolymer rubber and acrylonitrile-styrene block copolymer rubber.

[0160] In addition to the above conductive particles and the above binder resin, the above conductive material may contain various additives such as, for example, fillers, extenders, softeners, plasticizers, polymerization catalysts, curing catalysts, colorants, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, lubricants, antistatic agents, and flame retardants.

[0161] As a method for dispersing the above conductive particles in the above binder resin, a conventionally known dispersion method can be used. Examples of the method for dispersing the above conductive particles in the above binder resin include the following methods. A method of adding the above conductive particles to the above binder resin and then kneading and dispersing them with a planetary mixer or the like. A method of uniformly dispersing the above conductive particles in water or an organic solvent using a homogenizer or the like, then adding them to the above binder resin, and kneading and dispersing them with a planetary mixer or the like. A method of diluting the above binder resin with water or an organic solvent or the like, then adding the above conductive particles, and kneading and dispersing them with a planetary mixer or the like.

[0162] The viscosity (η25) of the above conductive material at 25°C is preferably 30 Pa·s or more, more preferably 50 Pa·s or more, preferably 400 Pa·s or less, and more preferably 300 Pa·s or less. When the viscosity of the above conductive material at 25°C is within the above lower limit and the above upper limit, the connection reliability between electrodes can be enhanced more effectively. The above viscosity (η25) can be appropriately adjusted according to the types and amounts of the compounding components.

[0163] The above viscosity (η25) can be measured, for example, using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., "TVE22L") under the conditions of 25°C and 5 rpm.

[0164] The above conductive material can be used as a conductive paste, a conductive film, or the like. When the conductive material according to the present invention is a conductive film, a film containing no conductive particles may be laminated on the conductive film containing conductive particles. The above conductive paste is preferably an anisotropic conductive paste. The above conductive film is preferably an anisotropic conductive film.

[0165] In 100% by weight of the above conductive material, the content of the above binder resin is preferably 10% by weight or more, more preferably 30% by weight or more, still more preferably 50% by weight or more, particularly preferably 70% by weight or more, and preferably 99.99% by weight or less, more preferably 99.9% by weight or less. When the content of the binder resin is equal to or more than the above lower limit and equal to or less than the above upper limit, conductive particles are efficiently arranged between the electrodes, and the connection reliability of the connection target members connected by the conductive material is further improved.

[0166] In 100% by weight of the above conductive material, the content of the above conductive particles is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and preferably 80% by weight or less, more preferably 60% by weight or less, still more preferably 40% by weight or less, still more preferably 20% by weight or less, particularly preferably 10% by weight or less. When the content of the conductive particles is equal to or more than the above lower limit and equal to or less than the above upper limit, the connection resistance between the electrodes can be made lower more effectively, and the connection reliability between the electrodes can be enhanced more effectively.

[0167] (Connection structure and method for manufacturing connection structure) The connection structure according to the present invention includes 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 according to the present invention, the connection portion is formed by conductive particles or a conductive material containing conductive particles and a binder resin, the conductive particles are the above-described conductive particles, and the first electrode and the second electrode are electrically connected by the conductive particles.

[0168] The above connection structure can be obtained through a process of disposing the conductive particles or the conductive material between the first connection target member and the second connection target member, and a process of conducting connection by thermocompression bonding. When the conductive particles have the insulating substance, it is preferable that the insulating substance desorbs from the conductive particles during the thermocompression bonding.

[0169] When the conductive particles are used alone, the connection portion itself is the conductive particles. That is, the first connection target member and the second connection target member are connected by the conductive particles. The conductive material used to obtain the above connection structure is preferably an anisotropic conductive material.

[0170] FIG. 6 schematically shows a front cross-sectional view of a connection structure using conductive particles according to the first embodiment of the present invention.

[0171] The connection structure 51 shown in FIG. 6 includes a first connection target member 52, a second connection target member 53, and a connection portion 54 that connects the first and second connection target members 52 and 53. The connection portion 54 is formed by curing a conductive material containing the conductive particles 1. In FIG. 6, the conductive particles 1 are schematically shown for convenience of illustration. Instead of the conductive particles 1, other conductive particles such as conductive particles 1A, 1B, 1C, and 1D may be used.

[0172] The manufacturing method of the above connection structure is not particularly limited. The manufacturing method of the above connection structure preferably includes the following steps.

[0173] A first placement step of placing the above-mentioned conductive particles or a conductive material containing the conductive particles and a binder resin on the surface of the first connection target member having the first electrode on its surface.

[0174] A second placement step of placing a second connection target member having a second electrode on its surface on the surface of the conductive particles or the conductive material opposite to the first connection target member side.

[0175] A step of applying a magnetic field or magnetic force before or after the second placement step.

[0176] In this way, a connection structure in which the first electrode and the second electrode are electrically connected by the conductive particles can be obtained.

[0177] Also, in the method for manufacturing the connection structure, it is preferable that a thermocompression bonding step is performed after the second placement step and after the step of applying the magnetic field or magnetic force. By thermocompression bonding a laminate of the first connection target member, the conductive particles or conductive material, and the second connection target member, a connection structure excellent in connection reliability can be obtained.

[0178] The pressure of the thermocompression bonding is preferably 40 MPa or more, more preferably 60 MPa or more, preferably 90 MPa or less, and more preferably 70 MPa or less. The heating temperature of the thermocompression bonding is preferably 80°C or more, more preferably 100°C or more, preferably 140°C or less, and more preferably 120°C or less. When the pressure and temperature of the thermocompression bonding are above the lower limit and below the upper limit, the conduction reliability and insulation reliability between the electrodes can be further enhanced. Also, when the conductive particles have the insulating particles, the insulating particles can be easily detached from the surface of the conductive particles during conductive connection.

[0179] When the conductive particles have the insulating particles, when heating and pressing the laminate, the insulating particles existing between the conductive particles and the first electrode and the second electrode can be excluded. For example, during the heating and pressing, the insulating particles existing between the conductive particles and the first electrode and the second electrode can easily desorb from the surface of the conductive particles. Note that during the heating and pressing, some of the insulating particles may desorb from the surface of the conductive particles, and the surface of the conductive portion may be partially exposed. By the exposed portion of the surface of the conductive portion contacting the first electrode and the second electrode, the first electrode and the second electrode can be electrically connected via the conductive particles.

[0180] The first connection target member and the second connection target member are not particularly limited. Specifically, examples of the first connection target member and the second connection target member include electronic components such as semiconductor chips, semiconductor packages, LED chips, LED packages, capacitors, and diodes, and circuit boards such as resin films, printed circuit boards, flexible printed circuit boards, flexible flat cables, rigid flexible boards, glass epoxy boards, and glass boards. The first connection target member and the second connection target member are preferably electronic components.

[0181] Examples of the electrode provided on the connection target member include metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, molybdenum electrodes, silver electrodes, SUS electrodes, and tungsten electrodes. When the connection target member is a flexible printed circuit board, the electrode is preferably a gold electrode, nickel electrode, tin electrode, silver electrode, or copper electrode. When the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, copper electrode, molybdenum electrode, silver electrode, or tungsten electrode. When the electrode is an aluminum electrode, it may be an electrode formed of only aluminum, or an electrode in which an aluminum layer is laminated 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.

[0182] Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited only to the following Examples. Note that the following Examples 18 to 23 and 32 to 34 are reference examples.

[0183] (Example 1) (1) Preparation of resin particles containing a magnetic substance Polystyrene particles having an average particle diameter of 0.5 μm were prepared as seed particles. 3.9 parts by weight of the polystyrene particles, 500 parts by weight of ion-exchanged water, and 120 parts by weight of a 5% by weight aqueous polyvinyl alcohol solution were mixed to prepare a mixed solution. After the mixed solution was dispersed by ultrasonic waves, it was placed in a separable flask and stirred uniformly.

[0184] Next, 150 parts by weight of divinylbenzene (monomer component), 2 parts by weight of 2,2'-azobis(isobutyric acid methyl) ("V-601" manufactured by Wako Pure Chemical Industries, Ltd.), and 2 parts by weight of benzoyl peroxide ("Niper BW" manufactured by NOF Corporation) were mixed. Further, 9 parts by weight of triethanolamine lauryl sulfate, 50 parts by weight of toluene (solvent), and 1100 parts by weight of ion-exchanged water were added to prepare an emulsion.

[0185] To the above mixture in the separable flask, the above emulsion was added, and the mixture was stirred for 12 hours to allow the seed particles to absorb the monomer, thereby obtaining a suspension containing seed particles swollen with the monomer.

[0186] Thereafter, 490 parts by weight of a 5 wt% aqueous polyvinyl alcohol solution was added, heating was started, and the reaction was carried out at 85 °C for 9 hours to obtain resin particles having an average particle diameter of 2.72 μm.

[0187] To a 300 mL beaker containing a stir bar, 1 part by weight of the obtained resin particles and 10 parts by weight of 20% sulfuric acid were weighed, and then stirred at 200 rpm and reacted at 25 °C for 1 hour.

[0188] Thereafter, to a 200 mL beaker containing a stir bar, 1 part by weight of the above resin particles, 2 parts by weight of iron(II) chloride tetrahydrate, and 25 mL of distilled water were weighed, and then stirred at 200 rpm for 1 hour at room temperature. Subsequently, filtration and washing with distilled water were carried out to obtain particles in which iron(II) ions were complexed. Thereafter, the above particles and 4 parts by weight of 28% aqueous ammonia (manufactured by Nacalai Tesque) were weighed and reacted at 25 °C for 1 hour under ultrasonic irradiation to obtain resin particles containing iron oxide as a magnetic substance (magnetic substance-encapsulated resin particles).

[0189] (2) Preparation of conductive particles The obtained resin particles containing a magnetic substance (magnetic substance-encapsulated resin particles) were washed and dried, and then 10 parts by weight of the magnetic substance-encapsulated resin particles were dispersed in 100 parts by weight of an alkaline solution containing 5 wt% of a palladium catalyst solution using an ultrasonic disperser, and then the solution was filtered to take out the magnetic substance-encapsulated resin particles. Next, the magnetic substance-encapsulated resin particles were added to 100 parts by weight of a 1 wt% solution of dimethylamine borane to activate the surface of the magnetic substance-encapsulated resin particles. After thoroughly washing the magnetic substance-encapsulated resin particles with activated surface with water, they were added to 500 parts by weight of distilled water and dispersed to obtain a dispersion.

[0190] In addition, a nickel plating solution (pH 8.5) containing 0.35 mol / L of nickel sulfate, 1.38 mol / L of dimethylamine borane, and 0.5 mol / L of sodium citrate was prepared.

[0191] While stirring the obtained suspension at 60° C., the above nickel plating solution was gradually added dropwise to the suspension to perform electroless nickel plating. Thereafter, the suspension was filtered to remove particles, washed with water, and dried to form a nickel-boron conductive layer on the surface of the magnetic core resin particles, thereby obtaining conductive particles having a conductive portion on the surface.

[0192] (3) Preparation of Conductive Material (Anisotropic Conductive Paste) 7 parts by weight of the obtained conductive particles, 25 parts by weight of bisphenol A type phenoxy resin, 4 parts by weight of fluorene type epoxy resin, 30 parts by weight of phenol novolak type epoxy resin, and SI-60L (manufactured by Sanshin Chemical Industry Co., Ltd.) were blended and defoamed and stirred for 3 minutes to obtain a conductive material (anisotropic conductive paste).

[0193] (4) Preparation of Connection Structure A transparent glass substrate having an IZO electrode pattern (first electrode, Vickers hardness of the metal on the surface of the electrode: 100 Hv) with an L / S of 10 μm / 10 μm formed on the upper surface was prepared. Also, a semiconductor chip having an Au electrode pattern (second electrode, Vickers hardness of the metal on the surface of the electrode: 50 Hv) with an L / S of 10 μm / 10 μm formed on the lower surface was prepared. The obtained anisotropic conductive paste was applied onto the transparent glass substrate to a thickness of 30 μm to form an anisotropic conductive paste layer. Next, the semiconductor chip was laminated on the anisotropic conductive paste layer such that the electrodes faced each other. Next, a magnetization treatment was performed from above the electrodes. Thereafter, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer reached 100° C., a pressure heating head was placed on the upper surface of the semiconductor chip, and a pressure of 85 MPa was applied to cure the anisotropic conductive paste layer at 100° C. to obtain a connection structure.

[0194] (Example 2) Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that the metal species of the conductive portion was changed to Ni—B / Au.

[0195] (Example 3) A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that the metal species of the conductive portion was changed to Ni-B / Pd.

[0196] (Example 4) A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that the metal species of the conductive portion was changed to Ni-B / Ag.

[0197] (Example 5) When producing the conductive portion, the reducing agent was changed from dimethylamine borane to sodium hypophosphite, and its concentration was further changed to 2.6 mol / L. The phosphorus content in the Ni plating film obtained at this time was 12% by weight. Further, the metal species of the conductive portion was changed to Ni-P / Au. A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except for these changes. Note that the obtained Ni-P / Au layer had lost its function as a magnetic material.

[0198] (Example 6) A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 5, except that the metal species of the conductive portion was changed to Ni-P / Pd.

[0199] (Example 7) A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 5, except that the metal species of the conductive portion was changed to Ni-P / Ag.

[0200] (Example 8) A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that the amount of iron(II) chloride tetrahydrate added was changed from 2 parts by weight to 5 parts by weight.

[0201] (Example 9) A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that the amount of iron(II) chloride tetrahydrate added was changed from 2 parts by weight to 4 parts by weight.

[0202] (Example 10) A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that the amount of iron(II) chloride tetrahydrate to be added was changed from 2 parts by weight to 3 parts by weight.

[0203] (Example 11) A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that the amount of iron(II) chloride tetrahydrate to be added was changed from 2 parts by weight to 1 part by weight.

[0204] (Example 12) A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that iron(II) chloride tetrahydrate and 28% aqueous ammonia were changed to cobalt(II) sulfate heptahydrate and dimethylamine borane.

[0205] (Example 13) A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that iron(II) chloride tetrahydrate and 28% aqueous ammonia were changed to nickel(II) sulfate hexahydrate and dimethylamine borane.

[0206] (Example 14) A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that iron(II) chloride tetrahydrate and 28% aqueous ammonia were changed to iron(III) sulfate heptahydrate and dimethylamine borane.

[0207] (Example 15) A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that the amount of divinylbenzene to be added was changed from 150 parts by weight to 50 parts by weight.

[0208] (Example 16) A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that the amount of divinylbenzene to be added was changed from 150 parts by weight to 40 parts by weight.

[0209] (Example 17) A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that the charged amount of the resin particles encapsulating the magnetic body was changed from 10 parts by weight to 15 parts by weight.

[0210] (Example 18) (1) Preparation of resin particles having a magnetic body part Resin particles were obtained in the same manner as in Example 1, except that the solvent used in the preparation of the resin particles was changed from toluene to ethanol. The average particle diameter of the obtained resin particles was 2.75 μm. Next, 2.0 g of the resin particles were dispersed in 40.0 g of ion-exchanged water by ultrasonic waves to obtain a core particle dispersion liquid.

[0211] Then, 8.0 mL of a magnetic fluid (manufactured by Ferrotec Corporation, containing Fe3O4 as a magnetic body) was added while stirring under ultrasonic irradiation, and ultrasonic dispersion was further performed for 30 minutes. The obtained dispersion liquid was filtered and washed with ion-exchanged water to obtain resin particles having a magnetic body part (resin particles containing a magnetic body part).

[0212] (2) Preparation of conductive particles After washing and drying the obtained resin particles containing a magnetic body part, 10 parts by weight of the resin particles containing a magnetic body part were dispersed in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, and then the solution was filtered to take out the resin particles containing a magnetic body part. Next, the resin particles containing a magnetic body part were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surface of the resin particles containing a magnetic body part. After thoroughly washing the resin particles containing a magnetic body part with an activated surface with water, they were added to 500 parts by weight of distilled water and dispersed to obtain a dispersion liquid.

[0213] In addition, a nickel plating solution (pH 8.5) containing 0.35 mol / L of nickel sulfate, 1.38 mol / L of dimethylamine borane, and 0.5 mol / L of sodium citrate was prepared.

[0214] While stirring the obtained suspension at 60 °C, the above nickel plating solution was gradually added dropwise to the suspension to perform electroless nickel plating. Thereafter, the suspension was filtered to take out the particles, washed with water, and dried, whereby a nickel-boron conductive layer was formed on the surface of the resin particles containing the magnetic body portion, and conductive particles having a conductive portion on the surface were obtained.

[0215] (3) Preparation of Conductive Material (Anisotropic Conductive Paste) In the same manner as in Example 1, a conductive material was obtained.

[0216] (4) Preparation of Connection Structure In the same manner as in Example 1, a connection structure was obtained.

[0217] (Example 19) Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 18, except that resin particles having an average particle diameter of 1.52 μm were used and the amount of the magnetic fluid to be added was changed to 4 mL.

[0218] (Example 20) Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 18, except that resin particles having an average particle diameter of 1.08 μm were used and the amount of the magnetic fluid to be added was changed to 2 mL.

[0219] (Example 21) When producing the conductive portion, the reducing agent was changed from dimethylamine borane to sodium hypophosphite, and further its concentration was changed to 2.6 mol / L. The phosphorus content in the Ni plating film obtained at this time was 12% by weight. Further, the metal species of the conductive portion was changed to Ni-P / Au. Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 18, except for these changes. The obtained Ni-P / Au layer had lost its function as a magnetic body.

[0220] (Example 22) Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 21, except that the metal species of the conductive portion was changed to Ni-P / Pd.

[0221] (Example 23) Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 21, except that the metal species of the conductive portion was changed to Ni-P / Ag.

[0222] (Example 24) Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that the amount of the 5 wt% polyvinyl alcohol aqueous solution to be added was changed from 490 parts by weight to 200 parts by weight, the amount of divinylbenzene to be added was changed from 150 parts by weight to 50 parts by weight, and the charged amount of the resin particles encapsulating magnetic bodies was changed from 10 parts by weight to 15 parts by weight.

[0223] (Example 25) Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that the amount of the 5 wt% polyvinyl alcohol aqueous solution to be added was changed from 490 parts by weight to 100 parts by weight, the amount of divinylbenzene to be added was changed from 150 parts by weight to 50 parts by weight, and the charged amount of the resin particles encapsulating magnetic bodies was changed from 10 parts by weight to 15 parts by weight.

[0224] (Example 26) Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that the amount of divinylbenzene to be added was changed from 150 parts by weight to 50 parts by weight, and 1 g of nickel particle slurry (average particle diameter: 100 nm) was added to the above dispersion over 3 minutes after the catalysis treatment to obtain a suspension containing resin particles encapsulating magnetic bodies with a core substance attached thereto.

[0225] (Example 27) Conductive particles were obtained in the same manner as in Example 1, except that the amount of divinylbenzene to be added was changed from 150 parts by weight to 50 parts by weight. Using these conductive particles, conductive particles with insulating particles were produced as follows.

[0226] (1) Production of insulating particles After putting the following monomer composition into a 1000 mL separable flask equipped with a four-neck separable cover, stirring blades, a three-way cock, a cooling tube, and a temperature probe, distilled water was added so that the solid content of the following monomer composition became 10% by weight, and it was stirred at 200 rpm, and polymerization was carried out at 60 °C for 24 hours under a nitrogen atmosphere. The above monomer composition contains 360 mmol of methyl methacrylate, 45 mmol of glycidyl methacrylate, 20 mmol of parasthyryldiethylphosphine, 13 mmol of ethylene glycol dimethacrylate, 0.5 mmol of polyvinylpyrrolidone, and 1 mmol of 2,2'-azobis{2-[N-(2-carboxyethyl)amidinopropane]}. After completion of the reaction, it was freeze-dried to obtain insulating particles (average particle diameter 360 nm) having phosphorus atoms derived from parasthyryldiethylphosphine on the surface.

[0227] (2) Preparation of Conductive Particles with Insulating Particles The insulating particles obtained in the above (1) were dispersed in distilled water under ultrasonic irradiation to obtain a 10% by weight aqueous dispersion of insulating particles. Further, 10 g of the obtained conductive particles were dispersed in 500 mL of distilled water, 1 g of a 10% by weight aqueous dispersion of insulating particles was added, and it was stirred at room temperature for 8 hours. After filtering with a 3 μm mesh filter, it was further washed with methanol and dried to obtain conductive particles with insulating particles.

[0228] Next, in the same manner as in Example 1, a conductive material and a connection structure were obtained.

[0229] (Example 28) Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 27, except that Ni particles (average particle diameter 100 nm) were attached to the resin particles during the preparation of the conductive particles.

[0230] (Example 29) When fabricating the conductive layer, a copper plating solution adjusted to pH 10.5 with ammonia was prepared, which was a mixed solution of 200 g / L of copper sulfate, 150 g / L of ethylenediaminetetraacetic acid, 100 g / L of sodium gluconate, and 50 g / L of formaldehyde. While stirring the suspension at 65 °C, the copper plating solution was dropped to perform electroless copper plating. Thereafter, the particles were taken out by filtration, washed with water, and dried to obtain conductive particles having a copper layer. Except for that, conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 1.

[0231] (Example 30) A tin plating solution adjusted to pH 8.5 with sodium hydroxide was prepared, which was a mixed solution containing 15 g / L of tin sulfate, 45 g / L of ethylenediaminetetraacetic acid, and 1.5 g / L of phosphinic acid. Also, a reducing solution adjusted to pH 10.0 with sodium hydroxide was prepared, which was a solution containing 5 g / L of sodium borohydride. After dropping the tin plating solution to perform electroless tin plating, it was reduced with the reducing solution. Thereafter, the particles were taken out by filtration, washed with water, and dried to obtain conductive particles having a tin layer. Except for that, conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 1.

[0232] (Example 31) Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 30, except that the amount of iron(II) chloride tetrahydrate added was changed from 2 parts by weight to 0.5 parts by weight.

[0233] (Example 32) Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 18, except that Cu plating was performed when forming the conductive layer.

[0234] (Example 33) Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 18, except that tin plating was performed when forming the conductive layer.

[0235] (Example 34) A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 33, except that ultrasonic dispersion was not performed after adding the magnetic fluid.

[0236] (Comparative Example 1) (1) Preparation of resin particles Resin particles were obtained in the same manner as in Example 1, except that the solvent used in the preparation of the resin particles was changed from toluene to ethanol. The average particle diameter of the resin particles was 2.75 μm.

[0237] (2) Preparation of conductive particles After washing and drying the obtained resin particles, 10 parts by weight of the resin particles were dispersed in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, and then the solution was filtered to remove the resin particles. Next, the resin particles were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surface of the resin particles. After thoroughly washing the resin particles with water whose surface was activated, they were added to 500 parts by weight of distilled water and dispersed to obtain a dispersion. Thereafter, conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 1.

[0238] (Comparative Example 2) Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Comparative Example 1, except that a nickel plating solution (pH 8.5) containing 0.8 mol / L of nickel sulfate, 2.0 mol / L of dimethylamine borane, and 1.0 mol / L of sodium citrate was prepared during the preparation of the conductive particles.

[0239] (Comparative Example 3) A conductive material and a connection structure were obtained in the same manner as in Comparative Example 1, except that nickel fine particles (average particle diameter 3.0 μm, coefficient of variation 20%) were used as the conductive particles.

[0240] (Comparative Example 4) The nickel fine particles used in Comparative Example 3 were gold-plated. A conductive material and a connection structure were obtained in the same manner as in Comparative Example 1, except that the gold-plated nickel fine particles were used as the conductive particles.

[0241] (Comparative Example 5) Conductive particles were obtained in the same manner as in Comparative Example 1. Then, using these conductive particles, conductive particles with insulating particles, a conductive material, and a connection structure were obtained in the same manner as in Example 27.

[0242] (Comparative Example 6) Conductive particles were obtained in the same manner as in Comparative Example 2. Then, using these conductive particles, conductive particles with insulating particles, a conductive material, and a connection structure were obtained in the same manner as in Example 27.

[0243] (Evaluation) (1) Saturation magnetization and remanent magnetization of conductive particles The saturation magnetization and remanent magnetization of the conductive particles were measured as follows using a magnetic property measuring device ("MPMS2" manufactured by Quantum Design Japan). The conductive particles were weighed into a capsule, attached to a sample holder, and the sample holder was installed in the apparatus main body. A magnetization curve was obtained by measurement under the conditions of a temperature of 25°C (constant temperature) and a maximum applied magnetic field of 10 kOe. The remanent magnetization and saturation magnetization were determined from the obtained magnetization curve.

[0244] [Judgment criteria for saturation magnetization] ○○: 30 emu / g or more ○: 20 emu / g or more and less than 30 emu / g △: 15 emu / g or more and less than 20 emu / g ×: Less than 15 emu / g

[0245] [Judgment criteria for remanent magnetization] ○○: Less than 1.2 emu / g ○: 1.2 emu / g or more and less than 2 emu / g △: 2 emu / g or more and less than 5 emu / g ×: 5 emu / g or more

[0246] [Judgment criteria for ratio (remanent magnetization / saturation magnetization)] ○○: 0 or more and less than 0.05 ○: 0.05 or more and less than 0.1 △: 0.1 or more and 0.4 or less ×: Exceeding 0.4

[0247] (2) Particle size and coefficient of variation (CV value) of conductive particles For the obtained conductive particles, using a particle size distribution measuring device ("Multisizer4" manufactured by Beckman Coulter), the particle sizes of about 100,000 resin particles were measured, and the average value was calculated. Also, from the measurement results of the particle sizes of the conductive particles, the coefficient of variation (CV value) of the particle sizes of the conductive particles was calculated from the following formula.

[0248] CV value (%) = (ρ / Dn) × 100 ρ: Standard deviation of the particle size of the coefficient of variation Dn: Average value of the particle size of the coefficient of variation

[0249] [Judgment criteria for coefficient of variation] ○○: 5% or less ○: Exceeding 5% and 8% or less △: Exceeding 8% and 10% or less ×: Exceeding 10%

[0250] (3) Thickness of conductive part and magnetic body part The obtained conductive particles were added to "Technovit 4000" manufactured by Kulzer so that the content was 30% by weight, and dispersed to prepare an embedded resin body for inspection. Using an ion milling device ("IM4000" manufactured by Hitachi High-Technologies Corporation), a cross-section of the conductive particles was cut out so as to pass through the vicinity of the center of the conductive particles dispersed in the embedded resin body for inspection.

[0251] Then, using a field emission transmission electron microscope (FE-TEM) ("JEM-ARM200F" manufactured by JEOL Ltd.), the image magnification was set to 50,000 times, 50 conductive particles were randomly selected, and the conductive part and magnetic body part of each conductive particle were observed. The thickness of the conductive part in each conductive particle was measured, and the arithmetic mean thereof was taken as the thickness of the conductive part and magnetic body part.

[0252] (4) Content of magnetic material By ICP emission spectrometry, the following contents were measured by the method described above.

[0253] Content (A1) (volume %), Content (A2) (weight %): In the conductive particles including Component A, the content of the magnetic substance included in the magnetic part among a total of 100 volume % or 100 weight % of the total of the content of the resin particles and the content of the magnetic part Content (B1) (volume %), Content (B2) (weight %): In the conductive particles including Component B, the content of the magnetic substance included in the conductive part among a total of 100 volume % or 100 weight % of the total of the content of the resin particles and the content of the conductive part Content (C1) (volume %), Content (C2) (weight %): In the conductive particles including Component C, the content of the magnetic substance included in the resin particles among 100 volume % or 100 weight % of the content of the resin particles Content (A3), (B3), (C3), (D) (volume %), Content (A4), (B4), (C4), (E) (weight %): The content of the magnetic substance included in the conductive particles among 100 volume % or 100 weight % of the conductive particles

[0254] (5) Connection resistance value (between the upper and lower electrodes) The connection resistance between the upper and lower electrodes of each of the obtained 20 connection structures was measured by the four-terminal method, and the average value of the connection resistance was calculated. Note that, based on the relationship of voltage = current × resistance, the connection resistance can be obtained by measuring the voltage when a constant current is passed. The connection resistance was judged according to the following criteria.

[0255] [Judgment criteria for connection resistance] ○○: The connection resistance is 2.0 Ω or less ○: The connection resistance exceeds 2.0 Ω and is 5.0 Ω or less △: The connection resistance exceeds 5.0 Ω and is 10 Ω or less ×: The connection resistance exceeds 10 Ω

[0256] (6) Short-circuit occurrence rate In the 20 connection structures obtained in the evaluation of the above (5) connection resistance value, the presence or absence of leakage between adjacent electrodes was measured with a tester for the resistance value, and the ratio of the connection structures with a resistance value of 10 8 Ω or less was evaluated as the short-circuit occurrence rate.

[0257] [Judgment criteria for short-circuit occurrence rate] ○○○: 0% ○○: More than 0% and less than 10% ○: 10% or more and less than 20% △: 20% or more and less than 50% ×: 50% or more

[0258] The results are shown in Tables 1 - 8 below.

[0259]

Table 1

[0260]

Table 2

[0261]

Table 3

[0262]

Table 4

[0263]

Table 5

[0264]

Table 6

[0265]

Table 7

[0266]

Table 8

Explanation of Symbols

[0267] 1, 1A, 1B, 1C, 1D… Conductive particles 1Ca, 1Da… Protrusions 2, 2A, 2B, 2C, 2D… Resin particles 3, 3A, 3B, 3C, 3D… Conductive parts 3Ca, 3Da… Protrusions 4, 4D… Magnetic parts 4B, 4C… Magnets 4Da… Protrusions 5… Core material 6… Insulating material 51… Connection structure 52… First connection target member 52a… First electrode 53… Second connection target member 53a… Second electrode 54… Connection part

Claims

1. Comprising resin particles and a conductive portion disposed outside the outer surface of the resin particles, The number average particle diameter of the conductive particles is 10 μm or less, The conductive particles are conductive particles having the following configuration C. Configuration C: The resin particles contain a magnetic material.

2. The conductive particles according to claim 1, further comprising the following configuration A or configuration B. Configuration A: Comprising a magnetic body portion containing a magnetic material disposed between the resin particles and the conductive portion, and the ratio of the residual magnetization to the saturation magnetization in the conductive particles is 0.4 or less. Configuration B: The conductive portion contains a magnetic material, and the ratio of the residual magnetization to the saturation magnetization in the conductive particles is 0.4 or less.

3. The conductive particles according to claim 1 or 2, wherein the content of the magnetic material contained in the conductive particles is 5% by volume or more and 85% by volume or less in 100% by volume of the conductive particles.

4. The conductive particles according to any one of claims 1 to 3, wherein the content of the magnetic material contained in the conductive particles is 10% by weight or more and 99% by weight or less in 100% by weight of the conductive particles.

5. The conductive particles according to any one of claims 1 to 4, wherein the number average particle diameter of the conductive particles is 0.1 μm or more and 10 μm or less.

6. The conductive particles according to any one of claims 1 to 5, wherein the magnetic material is a metal or a metal oxide.

7. The conductive particles according to any one of claims 1 to 6, wherein the magnetic material contains iron, cobalt, ferrite, nickel or an alloy thereof.

8. The conductive particles according to any one of claims 1 to 7, further comprising an insulating substance disposed on the outer surface of the conductive portion.

9. The conductive particles according to any one of claims 1 to 8, wherein the outer surface of the conductive portion has protrusions.

10. The conductive particles according to any one of claims 1 to 9, which are dispersed in a binder resin and used to obtain an anisotropic conductive material.

11. An electrically conductive material comprising the electrically conductive particles according to any one of claims 1 to 9 and A binder resin.

12. An anisotropic conductive material comprising conductive particles and A binder resin, The conductive particles comprise resin particles and a conductive portion disposed outside the outer surface of the resin particles, The conductive particles have the following configuration C. Configuration C: The resin particles contain a magnetic material.

13. A first connection target member having a first electrode on its surface, A second connection target member having a second electrode on its surface, A connection structure comprising a connection portion that connects the first connection target member and the second connection target member. The connection portion is formed of conductive particles or is formed of a conductive material including conductive particles and a binder resin. The conductive particles are the conductive particles according to any one of claims 1 to 9. A connection structure in which the first electrode and the second electrode are electrically connected by the conductive particles.

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