JP5216165B1 - Conductive particles, conductive materials, and connection structures - Google Patents

Abstract

Provided are conductive particles that can suppress aggregation of a plurality of conductive particles, and can reduce the connection resistance between electrodes when used for connection between electrodes, and a conductive material using the conductive particles To do.
The electroconductive particle 1 which concerns on this invention is arrange | positioned on the surface of the base material particle 2, the base material particle 2, and nickel, boron, and at least 1 sort (s) of metal component in tungsten and molybdenum. And a conductive layer 3 included. The conductive material according to the present invention includes conductive particles 1 and a binder resin.

Description

  The present invention relates to conductive particles in which a conductive layer is arranged on the surface of base particles, and more particularly to conductive particles that can be used for electrical connection between electrodes, for example. The present invention also relates to a conductive material and a connection structure using the conductive particles.

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

  The anisotropic conductive material is used for connection between an IC chip and a flexible printed circuit board, connection between an IC chip and a circuit board having an ITO electrode, and the like. For example, after disposing an anisotropic conductive material between the electrode of the IC chip and the electrode of the circuit board, these electrodes can be electrically connected by heating and pressing.

  As an example of the conductive particles, the following Patent Document 1 discloses a conductive material in which a nickel conductive layer or a nickel alloy conductive layer is formed on the surface of spherical base particles having an average particle diameter of 1 to 20 μm by an electroless plating method. Sex particles are disclosed. The conductive particles have minute protrusions of 0.05 to 4 μm on the outermost layer of the conductive layer. The conductive layer and the protrusion are substantially continuously connected.

Patent Document 2 below discloses conductive particles having base particles and a conductive layer formed on the surface of the base particles. In order to form the base particles, a divinylbenzene-ethylvinylbenzene mixture is used as part of the monomer. In this conductive particle, when 10% of the particle diameter is displaced, the compression elastic modulus is 2.5 × 10 ⁹ N / m ² or less, the compression deformation recovery rate is 30% or more, and the fracture strain is 30% or more. is there. Patent Document 2 describes that when the electrodes of the substrate are electrically connected using the conductive particles, the connection resistance is reduced and the connection reliability is increased.

JP 2000-243132 A JP 2003-313304 A

  When the electrodes are connected using the conductive particles described in Patent Document 1, the connection resistance between the electrodes may increase. Moreover, when the electrodes are connected using an anisotropic conductive material containing conductive particles described in Patent Document 1, the resin component between the electrodes and the conductive particles may not be sufficiently eliminated. For this reason, the connection resistance between the electrodes connected by the conductive particles contained in the anisotropic conductive material may increase.

  Moreover, in the electroconductive particle of the Example of patent document 1, the electroconductive layer containing nickel and phosphorus is formed. In many cases, an oxide film is formed on the surfaces of the electrodes connected by the conductive particles and the conductive layer of the conductive particles. When conductive particles having a conductive layer containing nickel and phosphorus are connected between the electrodes, the conductive layer containing nickel and phosphorus is relatively soft. It may not be sufficiently eliminated, and the connection resistance may increase.

  Moreover, when the thickness of the conductive layer containing nickel and phosphorus as described in Patent Document 1 is increased in order to reduce the connection resistance, the connection target member or the substrate may be damaged by the conductive particles. When the connection target member or the electrode is damaged, the connection resistance tends to increase. Further, when the electrode or the connection target member is damaged, conduction reliability between the electrodes is lowered.

  Furthermore, in the conventional conductive particles as described in Patent Document 1, a plurality of conductive particles may aggregate. When electrodes are connected using a plurality of aggregated conductive particles, a short circuit between the electrodes may occur.

  Further, even with the conductive particles described in Patent Document 2, the oxide film may not be sufficiently removed, or damage to the connection target member or the substrate may not be suppressed. For this reason, even when the conductive particles described in Patent Document 2 are used, it is difficult to sufficiently reduce the connection resistance between the electrodes.

  An object of the present invention is to suppress the aggregation of a plurality of conductive particles, and further to reduce the connection resistance between electrodes when used for connection between electrodes, and the conductive particles It is to provide a conductive material and a connection structure used.

  A limited object of the present invention is that when used for connection between electrodes, the conductive particles that can effectively eliminate the oxide film on the surface of the electrode and conductive particles, and can reduce the connection resistance between the electrodes. And providing a conductive material and a connection structure using the conductive particles.

  The limited object of the present invention is to provide a conductive material that can effectively eliminate the resin component between the electrode and the conductive particles and reduce the connection resistance between the electrodes when used for connection between the electrodes. And providing a connection structure.

  According to a wide aspect of the present invention, a conductive material is disposed on the surface of the substrate particle and includes nickel, boron, and at least one metal component of tungsten and molybdenum. Conductive particles having a layer are provided.

  On the specific situation with the electroconductive particle which concerns on this invention, content of the said boron in the whole 100 weight% of the said conductive layer is 0.05 weight% or more and 4 weight% or less.

  On the specific situation with the electroconductive particle which concerns on this invention, content of the said metal component in 100 weight% of the whole of the said conductive layer is 0.1 to 30 weight%.

  On the specific situation with the electroconductive particle which concerns on this invention, content of the said metal component in 100 weight% of the whole said conductive layer is more than 5 weight%, and is 30 weight% or less.

  On the specific situation with the electroconductive particle which concerns on this invention, the said metal component contains tungsten.

In a specific aspect of the conductive particles according to the present invention, the compression modulus when the conductive particles and 10% compressive deformation is 5000N / mm ² or more and 15000 N / mm ² or less.

  In a specific aspect of the conductive particles according to the present invention, the compression recovery rate is 5% or more and 70% or less.

  On the specific situation with the electroconductive particle which concerns on this invention, the said metal component contains molybdenum.

  On the specific situation with the electroconductive particle which concerns on this invention, the said conductive layer contains nickel and molybdenum, and content of nickel is 70 weight% or more and 99.9 weight% in the whole 100 weight% of the said conductive layer. The molybdenum content is 0.1 wt% or more and 30 wt% or less.

In a specific aspect of the conductive particles according to the present invention, the compression elastic modulus when compressed by 5% is 7000 N / mm ² or more, and 10% of the particle size of the conductive particles before compression in the compression direction. And when the conductive particles are compressed at 25% or less, the conductive layer is cracked.

  On the specific situation with the electroconductive particle which concerns on this invention, the thickness of the said conductive layer is 0.05 micrometer or more and 0.5 micrometer or less.

  On the specific situation with the electroconductive particle which concerns on this invention, the said conductive layer has a processus | protrusion on an outer surface.

  The conductive material according to the present invention includes the conductive particles described above and a binder resin.

  The connection structure according to the present invention includes a first connection target member, a second connection target member, and a connection portion connecting the first and second connection target members, and the connection The part is formed of the above-described conductive particles, or is formed of a conductive material including the conductive particles and a binder resin.

  In the conductive particle according to the present invention, a conductive layer containing nickel, boron, and at least one metal component of tungsten and molybdenum is disposed on the surface of the base particle, and thus a plurality of conductive The aggregation of the conductive particles can be suppressed. Furthermore, when the electrodes are connected using the conductive particles according to the present invention, the connection resistance can be lowered.

FIG. 1 is a cross-sectional view showing conductive particles according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing conductive particles according to the second embodiment of the present invention. FIG. 3 is a cross-sectional view showing conductive particles according to the third embodiment of the present invention. FIG. 4 is a front cross-sectional view schematically showing a connection structure using conductive particles according to the first embodiment of the present invention. FIG. 5 is a schematic cross-sectional view for explaining a state when the conductive particles are compressed. FIG. 6 is a schematic diagram illustrating an example of the relationship between the compression load value and the compression displacement when a crack occurs in the conductive layer when the conductive particles are compressed.

  Details of the present invention will be described below.

  The conductive particle according to the present invention is a conductive particle that is disposed on the surface of the substrate particle, nickel, boron, and at least one metal component of tungsten and molybdenum. And having a layer. The conductive layer is a nickel-boron-tungsten / molybdenum conductive layer. Hereinafter, at least one metal component of tungsten and molybdenum may be referred to as a metal component M. Hereinafter, the conductive layer containing nickel, boron, and the metal component M may be referred to as a conductive layer X.

  By adopting the above-described configuration in the conductive particles according to the present invention, aggregation of a plurality of conductive particles can be suppressed. As a result of suppressing the aggregation of the plurality of conductive particles, a short circuit between the electrodes can be effectively prevented. Furthermore, by adopting the above-described configuration in the conductive particles according to the present invention, when the electrodes are connected using the conductive particles according to the present invention, the connection resistance can be lowered.

  When the electrodes are connected by conductive particles having a conductive layer containing nickel, the connection resistance between the electrodes is reduced. When the content of nickel in 100% by weight of the entire conductive layer X in the conductive particles according to the present invention is 50% by weight or more, the connection resistance between the electrodes becomes considerably low. Accordingly, the content of nickel is preferably 50% by weight or more in the entire conductive layer X of 100% by weight.

  In addition, in the conductive particles having a nickel conductive layer that does not contain boron, the nickel conductive layer that does not contain boron is too soft, and the oxide film on the surface of the electrode and conductive particles can be sufficiently eliminated when connecting the electrodes. However, the connection resistance may increase. For example, in conductive particles having a conductive layer containing nickel and phosphorus, the oxide film on the surfaces of the electrodes and the conductive particles cannot be sufficiently removed, and the connection resistance tends to be high. In particular, when the phosphorus content in the total 100% by weight of the conductive layer is 10.5% by weight or more, the connection resistance tends to increase, and when it is 1% by weight or more, the connection resistance tends to further increase.

  On the other hand, if the thickness of the conductive layer containing nickel and phosphorus is increased in order to reduce the connection resistance, the connection target member or the substrate may be damaged by the conductive particles.

  On the other hand, since the hardness of the conductive layer X containing nickel and boron is relatively high, the connection resistance between the electrodes can be lowered. When connecting the electrodes, the oxide film on the surfaces of the electrodes and the conductive particles can be eliminated, and the connection resistance can be lowered.

  Furthermore, in the conductive particles according to the present invention, the conductive layer X includes not only boron but also at least one metal component M of tungsten and molybdenum. Therefore, the conductive layer X including boron and the metal component M is included. Can be quite stiff. For this reason, the oxide film on the surface of the electrode and the conductive particles can be sufficiently eliminated, and the connection resistance can be considerably reduced. Particularly when the conductive layer X contains the metal component M and the conductive layer X has protrusions on the outer surface, the oxide film on the surface of the electrode and conductive particles can be more effectively eliminated, and the connection resistance can be reduced. It can be made even lower.

  Furthermore, since the conductive layer X contains the metal component M, the conductive layer X is considerably hardened. As a result, even if an impact is applied to the connection structure connecting the electrodes by the conductive particles, a conduction failure occurs. It becomes difficult. That is, the impact resistance of the connection structure can be increased.

  Furthermore, the surface of the conductive layer of the conventional conductive particles may be highly magnetic, and the surface of the conductive layer containing nickel and boron is highly magnetic. Therefore, when the electrodes are electrically connected, Due to the influence of the agglomerated conductive particles, the electrodes adjacent in the horizontal direction tend to be easily connected. In the conductive particles according to the present invention, since the conductive layer X contains the metal component M, the magnetic property of the surface of the conductive layer X is considerably low. For this reason, it can suppress that several electroconductive particle aggregates. Therefore, when the electrodes are electrically connected, it is possible to prevent the electrodes adjacent in the lateral direction from being connected by the aggregated conductive particles. That is, a short circuit between adjacent electrodes can be further prevented.

  In 100% by weight of the entire conductive layer X, the content of nickel is 70% by weight or more and 99.9% by weight or less, and the content of the metal component M is 0.1% by weight or more and 30% by weight. The following is preferable. Furthermore, it is preferable that the conductive layer X does not contain phosphorus, or the conductive layer X contains phosphorus, and the content of phosphorus in 100% by weight of the entire conductive layer X is less than 1% by weight.

  In 100% by weight of the entire conductive layer X, the content of nickel is 70% by weight or more and 99.9% by weight or less, and the content of the metal component M is 0.1% by weight or more and 30% by weight or less. It is preferable that the conductive layer X does not contain phosphorus, or the conductive layer X contains phosphorus, and the content of phosphorus in 100% by weight of the entire conductive layer X is less than 1% by weight. When the conductive particles having this preferable configuration are used for the connection between the electrodes, the oxide film on the surfaces of the electrodes and the conductive particles can be effectively eliminated. For this reason, the connection resistance between the electrodes in the obtained connection structure can be further reduced. Moreover, since the content of nickel in the conductive particles having this preferable configuration is 70% by weight or more, the connection resistance between the electrodes becomes considerably low.

  Further, when the content of the metal component M in 100% by weight of the entire conductive layer X is 0.1% by weight or more and 30% by weight or less, compared with a conductive layer not containing the metal component M, The conductive layer X becomes considerably hard. For this reason, as a result of effectively eliminating the oxide film on the surfaces of the electrodes and the conductive particles, the connection resistance between the electrodes is further reduced. In addition, when conductive particles and a binder resin are blended and the electrodes are connected using a conductive material, the resin component between the electrodes and the conductive particles can be effectively eliminated, so that the connection between the electrodes The resistance becomes even lower.

The compression elastic modulus (10% K value) when the conductive particles according to the present invention are 10% compressively deformed is preferably 5000 N / mm ² or more, more preferably 7000 N / mm ² or more, preferably 15000 N / mm ² or less. More preferably, it is 10,000 N / mm ² or less. When the compression elastic modulus (10% K value) is not less than the above lower limit, the oxide film on the surface of the electrode and the conductive particles can be more effectively eliminated, and the resin component between the electrode and the conductive particles can be further removed. As a result of more effective elimination, the connection resistance between the electrodes is further reduced.

  The compression elastic modulus (10% K value) can be measured as follows.

  Using a micro-compression tester, the conductive particles are compressed under the conditions of a compression speed of 2.6 mN / sec and a maximum test load of 10 gf on the end face of a cylindrical indenter (diameter 50 μm, made of diamond). The load value (N) and compression displacement (mm) at this time are measured. From the measured value obtained, the compression elastic modulus can be obtained by the following formula. As the micro compression tester, for example, “Fischer Scope H-100” manufactured by Fischer is used.

K value (N / mm ² ) = (3/2 ^1/2 ) · F · S ⁻³ / ² · R ^−1/2
F: Load value when the conductive particles are 10% compressively deformed (N)
S: Compression displacement (mm) when the conductive particles are 10% compressively deformed
R: radius of conductive particles (mm)

  The compression recovery rate of the conductive particles is preferably 5% or more, more preferably 20% or more, preferably 70% or less, more preferably 60% or less, and still more preferably 50% or less. When the compression recovery rate is not less than the above lower limit and not more than the above upper limit, the oxide film on the surface of the electrode and the conductive particles can be more effectively eliminated, and the resin component between the electrode and the conductive particles is further more effective. As a result, the connection resistance between the electrodes can be further reduced. Furthermore, peeling is further less likely to occur at the interface between the cured product and the portion of the connection portion excluding the conductive particles and the conductive particles and the connection target member. Furthermore, as a result of suppressing the repulsive force of the conductive particles used for the connection between the electrodes, the conductive material is difficult to peel from the substrate or the like. This also makes the connection resistance between the electrodes even lower.

  The compression recovery rate can be measured as follows.

  Spread conductive particles on the sample stage. With respect to one dispersed conductive particle, a load (reverse load value) is applied to the central direction of the conductive particle until the conductive particle is compressed and deformed by 30% using a micro compression tester. Thereafter, unloading is performed up to the origin load value (0.40 mN). The load-compression displacement during this period is measured, and the compression recovery rate can be obtained from the following equation. The load speed is 0.33 mN / sec. As the micro compression tester, for example, “Fischer Scope H-100” manufactured by Fischer is used.

Compression recovery rate (%) = [(L1-L2) / L1] × 100
L1: Compression displacement from the load value for origin to the reverse load value when applying a load L2: Unloading displacement from the reverse load value to the load value for origin when releasing the load

  The compression elastic modulus and the compression recovery rate are the kind of the base particle, the particle diameter of the base particle, the content of nickel in 100% by weight of the whole conductive layer X, and the whole conductive layer X. The content of the metal component M in 100% by weight, the content of phosphorus in the whole 100% by weight of the conductive layer X, the content of boron in the whole 100% by weight of the conductive layer X, the content of the conductive layer X It can be appropriately adjusted depending on the thickness.

In the conductive particles according to the present invention, the compression modulus (5% K value) when compressed by 5% is preferably 7000 N / mm ² or more.

  Furthermore, in the conductive particles according to the present invention, the conductive layer is cracked when the conductive particles are compressed by more than 10% and 25% or less of the particle diameter of the conductive particles before compression in the compression direction. It is preferable. In other words, when the conductive particles according to the present invention are compressed, the conductive particles exceed 10% of the particle diameter of the conductive particles before compression in the compression direction and are compressed and displaced at 25% or less. It is preferable that a crack occurs in the conductive layer. That is, the compressive displacement of the conductive particles that cause cracks in the conductive layer is preferably more than 10% and 25% or less. For example, when the conductive particles are significantly compressed, the conductive layer is moderately partially broken. The conductive particles having such properties not only have a sufficiently high hardness at the initial stage of compression, but also crack when appropriately compressed. Since the conductive layer is cracked at the stage where the conductive particles are appropriately compressed during the connection between the electrodes, damage to the electrodes can be suppressed. As a result, the connection resistance between the electrodes in the obtained connection structure can be further reduced, and the conduction reliability between the electrodes can be further increased.

In the conductive particles according to the present invention, when the compression elastic modulus (5% K value) when compressed at 5% is 7000 N / mm ² or more and the conductive particles according to the present invention are compressed, the compression direction When the conductive particles are compressed at more than 10% and less than 25% of the particle diameter of the conductive particles before compression, it is preferable that the conductive layer is cracked. When the conductive particles having this preferable configuration are used for connection between the electrodes, the connection resistance between the electrodes can be further reduced.

In the conductive particles according to the present invention, when the compression elastic modulus (5% K value) when compressed by 5% is 7000 N / mm ² or more, the conductive particles in the initial stage of compression have sufficient hardness. Have For this reason, the oxide film on the surface of the electrode and the conductive particles can be effectively eliminated at the initial stage of compression of the conductive particles at the time of connection between the electrodes. As a result, the electrode and the conductive layer in the conductive particles are effectively in contact, and the connection resistance between the electrodes can be further reduced.

On the other hand, when the electrodes are electrically connected using conductive particles having a compression modulus (5% K value) of less than 7000 N / mm ² when compressed by 5%, the compression is 5%. Compared with the case where the electrodes are electrically connected to each other using conductive particles having a compressive elastic modulus (5% K value) of 7000 N / mm ² or more, the oxide film on the surfaces of the electrodes and the conductive particles There is a tendency that the elimination property of the electrode decreases, and the connection resistance between the electrodes tends to increase.

From the viewpoint of the connection resistance between the electrodes further low, the 5% K value is more preferably 8000 N / mm ² or more, further preferably 9000 N / mm ² or more. The upper limit of the 5% K value is not particularly limited. The 5% K value may be, for example, 15000 N / mm ² or less or 10000 N / mm ² or less.

  The compression elastic modulus (5% K value) can be measured as follows.

  Using a micro-compression tester, the conductive particles are compressed under the conditions of a compression speed of 2.6 mN / sec and a maximum test load of 10 gf on the end face of a cylindrical indenter (diameter 50 μm, made of diamond). The load value (N) and compression displacement (mm) at this time are measured. From the measured value obtained, the compression elastic modulus can be obtained by the following formula. As the micro compression tester, for example, “Fischer Scope H-100” manufactured by Fischer is used.

K value (N / mm ² ) = (3/2 ^1/2 ) · F · S ⁻³ / ² · R ^−1/2
F: Load value when the conductive particles are compressively deformed by 5% (N)
S: Compression displacement (mm) when conductive particles are 5% compressively deformed
R: radius of conductive particles (mm)

  The compression elastic modulus (10% K value and 5% K value) universally and quantitatively represents the hardness of the conductive particles. By using the compression elastic modulus, the hardness of the conductive particles can be expressed quantitatively and uniquely.

  From the viewpoint of further reducing the connection resistance between the electrodes, the compression displacement at which the conductive layer is cracked is more preferably 12% or more, and more preferably 20% or less.

  Hereinafter, the present invention will be clarified by describing specific embodiments and examples of the present invention with reference to the drawings.

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

  As shown in FIG. 1, the conductive particle 1 includes a base particle 2, a conductive layer 3, a plurality of core substances 4, and a plurality of insulating substances 5.

  The conductive layer 3 is disposed on the surface of the base particle 2. The conductive layer 3 includes nickel, boron, and the metal component M. The conductive layer 3 is a nickel-boron-tungsten / molybdenum conductive layer. The conductive particle 1 is a coated particle in which the surface of the base particle 2 is coated with the conductive layer 3.

  The conductive particles 1 have a plurality of protrusions 1a on the surface. The conductive layer 3 has a plurality of protrusions 3a on the outer surface. A plurality of core substances 4 are arranged on the surface of the base particle 2. A plurality of core materials 4 are embedded in the conductive layer 3. The core substance 4 is disposed inside the protrusions 1a and 3a. The conductive layer 3 covers a plurality of core materials 4. The outer surface of the conductive layer 3 is raised by the plurality of core materials 4 to form protrusions 1a and 3a.

  The conductive particles 1 have an insulating material 5 disposed on the outer surface of the conductive layer 3. At least a part of the outer surface of the conductive layer 3 is covered with the insulating material 5. The insulating substance 5 is made of an insulating material and is an insulating particle. Thus, the electroconductive particle which concerns on this invention may have the insulating substance arrange | positioned on the outer surface of an electroconductive layer. However, the conductive particles according to the present invention do not necessarily have an insulating material.

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

  The conductive particles 11 shown in FIG. 2 include base material particles 2, a second conductive layer 12 (another conductive layer), a conductive layer 13 (first conductive layer), a plurality of core substances 4, and a plurality of And an insulating material 5.

  Only the conductive layer is different between the conductive particles 1 and the conductive particles 11. That is, the conductive particle 1 has a single-layered conductive layer, whereas the conductive particle 11 has a two-layered second conductive layer 12 and conductive layer 13.

  The conductive layer 13 is disposed on the surface of the base particle 2. A second conductive layer 12 (another conductive layer) is disposed between the base particle 2 and the conductive layer 13. Therefore, the second conductive layer 12 is disposed on the surface of the base particle 2, and the conductive layer 13 is disposed on the surface of the second conductive layer 12. The conductive layer 13 includes nickel, boron, and tungsten. The conductive layer 13 has a plurality of protrusions 13a on the outer surface. The conductive particles 11 have a plurality of protrusions 11a on the surface.

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

  The conductive particles 21 shown in FIG. 3 have base material particles 2 and a conductive layer 22. The conductive layer 22 is disposed on the surface of the base particle 2. The conductive layer 22 includes nickel, boron, and the metal component M.

  The conductive particles 21 do not have a core substance. The conductive particles 21 do not have protrusions on the surface. The conductive particles 21 are spherical. The conductive layer 22 has no protrusion on the surface. Thus, the electroconductive particle which concerns on this invention does not need to have a processus | protrusion, and may be spherical. Further, the conductive particles 21 do not have an insulating material. However, the conductive particles 21 may have an insulating material disposed on the surface of the conductive layer 22.

  In the conductive particles 1, 11, and 21, the nickel content is 70 wt% or more and 99.9 wt% or less in 100 wt% of the entire conductive layers 3, 13, and 22, and the content of the metal component M is Is preferably 0.1% by weight or more and 30% by weight or less. Further, the conductive layers 3, 13, and 22 do not contain phosphorus, or the conductive layers 3, 13, and 22 contain phosphorus, and the total content of the conductive layers 3, 13, and 22 is 100% by weight. It is preferable that it is less than%.

The 5% K value of the conductive particles 1, 11 and 21 is preferably 7000 N / mm ² or more. Further, when the conductive particles 1, 11, 21 are compressed, the conductive particles 1, 11, 21 exceed 10% of the particle diameter of the conductive particles 1, 11, 21 before compression in the compression direction, 25 It is preferable that cracks occur in the conductive layers 3, 13, and 22 when they are compressed and displaced by less than or equal to%. That is, in the conductive particles 1, 11, and 21, when the particle diameter of the conductive particles 1, 11, 21 before compression in the compression direction is X, the particle diameter of the conductive particles 1, 11, 21 in the compression direction Is preferably 0.75X or more and less than 0.90X, it is preferable that the conductive layers 3, 13, and 22 are cracked. For example, when the particle diameter of the conductive particles 1, 11, 21 before compression in the compression direction is 5 μm, the conductive particles 1, 11, 21 are compressed and the conductive particles 1, 11, 11 in the compression direction are compressed. When the particle diameter of 21 is 3.75 μm or more and less than 4.5 μm, it is preferable that cracks occur in the conductive layers 3, 13, and 22. In the conductive particles 11, not only the conductive layer 13 but also the second conductive layer 12 may be cracked.

  The “crack” indicates the first (first) crack in the conductive layer. Therefore, in the electroconductive particle 1,11,21 which concerns on this embodiment, when the electroconductive particle 1,11,21 which has the electroconductive layer 3,13,22 without a crack is compressed, electroconductive particle 1,11,21 It is preferable that cracking occurs in the conductive layers 3, 13, and 22 when 21 exceeds 10% of the particle diameter of the conductive particles 1, 11 and 21 before compression in the compression direction and is 25% or less.

  Specifically, the measurement of the compression displacement at which the conductive layers 3, 13, and 22 are cracked is performed as follows. In FIG. 5, the conductive particles 21 are used.

  As shown in FIG. 5, the conductive particles 21 are placed on the base 71. Using a micro compression tester (“Fischerscope H-100” manufactured by Fischer), a cylinder (diameter 50 μm, made of diamond) is used as the compression member 72 under the conditions of a compression speed of 0.33 mN / sec and a maximum test load of 10 mN. The smooth end surface 72a of the compression member 72 is lowered toward the conductive particles 21 in the direction indicated by the arrow A. The conductive particles 21 are compressed by the smooth end surface 72a. The compression is continued until the crack 22a is partially generated in the conductive layer 22 of the conductive particles 21. In the case of conductive particles 1 and 11, the same measurement is performed.

  In the cross-sectional view shown in FIG. 5, the state in which the crack 22 a is formed in the conductive layer 22 at the upper and lower portions of the conductive particles 21 is illustrated, but the position at which the crack is generated in the conductive layer is not particularly limited.

  When the conductive particles are compressed as described above, the conductive layer cracks when the conductive particles are compressed and displaced by more than 10% of the particle diameter of the conductive particles before compression in the compression direction. It is preferable that the conductive layer is cracked at a compression displacement of 25% or less.

  When the compressive load value and the compressive displacement are measured while compressing the conductive particles, the relationship between the compressive load value and the compressive displacement is, for example, as shown in FIG. In FIG. 6, the compression is started from the point A0, and the conductive layer is cracked at the point A1. As the conductive layer cracks, the compression displacement (particle diameter) of the conductive particles in the compression direction changes, and the compression displacement moves from the A1 point to the A2 point. When compressing, a compressive load is applied to the conductive particles, and if the conductive layer cracks, the conductive particles are compressed with a relatively small compressive load. Therefore, the compression member that applies the compressive load to the conductive particles moves. The compression displacement (particle diameter) of the conductive particles in the compression direction changes.

In FIG. 6, the slope of the line from point A0 to point A1 is relatively large. When the 5% K value of the conductive particles 21 is 7000 N / mm ² or more and the conductive particles 21 are relatively hard, the slope of the line from the A0 point to the A1 point becomes large.

[Base material particles]
Examples of the substrate particles include resin particles, inorganic particles excluding metal particles, organic-inorganic hybrid particles, and metal particles. The substrate particles are preferably substrate particles excluding metal particles, and are preferably resin particles, inorganic particles excluding metal particles, or organic-inorganic hybrid particles.

  The substrate particles are preferably resin particles formed of a resin. When connecting between electrodes using the said electroconductive particle, after arrange | positioning the said electroconductive particle between electrodes, the said electroconductive particle is compressed by crimping | bonding. When the substrate particles are resin particles, the conductive particles are easily deformed during the pressure bonding, and the contact area between the conductive particles and the electrode is increased. For this reason, the conduction | electrical_connection reliability between electrodes becomes high.

  Examples of the resin for forming the resin particles include polyolefin resin, acrylic resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, and polyphenylene. Examples thereof include oxide, polyacetal, polyimide, polyamideimide, polyetheretherketone, polyethersulfone, divinylbenzene polymer, and divinylbenzene copolymer. Examples of the divinylbenzene copolymer include divinylbenzene-styrene copolymer and divinylbenzene- (meth) acrylic acid ester copolymer. Since the hardness of the substrate particles can be easily controlled within a suitable range, the resin for forming the resin particles is obtained by polymerizing one or more polymerizable monomers having a plurality of ethylenically unsaturated groups. A polymer is preferred.

  Examples of the inorganic substance for forming the inorganic particles include silica and carbon black. Examples of the organic / inorganic hybrid particles include organic / inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

  When the substrate particles are metal particles, examples of the metal for forming the metal particles include silver, copper, nickel, silicon, gold, and titanium.

  The particle diameter of the substrate particles is preferably 0.1 μm or more, more preferably 1 μm or more, still more preferably 1.5 μm or more, particularly preferably 2 μm or more, preferably 1000 μm or less, more preferably 500 μm or less, and even more preferably. Is not more than 300 μm, more preferably not more than 50 μm, particularly preferably not more than 30 μm, and most preferably not more than 5 μm. When the particle diameter of the substrate particles is equal to or greater than the above lower limit, the contact area between the conductive particles and the electrodes is increased, so that the conduction reliability between the electrodes is further increased, and the electrodes are connected via the conductive particles. The connection resistance between them becomes even lower. Further, when forming the conductive layer on the surface of the base particle by electroless plating, it becomes difficult to aggregate and it becomes difficult to form the aggregated conductive particles. When the particle diameter is not more than the above upper limit, the conductive particles are easily compressed, the connection resistance between the electrodes is further reduced, and the distance between the electrodes is further reduced. The particle diameter of the base particle indicates a diameter when the base particle is a true sphere, and indicates a maximum diameter when the base particle is not a true sphere.

  The particle diameter of the substrate particles is particularly preferably 2 μm or more and 5 μm or less. When the particle diameter of the substrate particles is in the range of 2 to 5 μm, even when the distance between the electrodes is small and the thickness of the conductive layer is increased, small conductive particles can be obtained.

[Conductive layer]
The electroconductive particle which concerns on this invention is arrange | positioned on the surface of base material particle | grains, and has the electroconductive layer X containing at least 1 sort (s) of the metal component M of nickel, boron, tungsten, and molybdenum. The conductive layer X may be directly laminated on the surface of the base particle, or may be disposed on the surface of the base particle via another conductive layer or the like. Furthermore, another conductive layer may be disposed on the surface of the conductive layer X. It is preferable that no other conductive layer is disposed on the outer surface of the conductive layer X. It is preferable that the outer surface of the conductive particles is a conductive layer X containing nickel. When the electrodes are connected by conductive particles having the conductive layer X containing nickel, the connection resistance is further reduced.

  The conductive layer X includes nickel, boron, at least one metal component M of tungsten and molybdenum. The conductive layer X is a nickel-boron-tungsten / molybdenum conductive layer. The conductive layer X preferably includes nickel, boron, and tungsten, preferably includes nickel, boron, and molybdenum, and preferably includes nickel, boron, tungsten, and molybdenum. The conductive layer X may be a nickel-boron-tungsten conductive layer or a nickel-boron-molybdenum conductive layer. The metal component M preferably contains tungsten, preferably contains molybdenum, and preferably contains tungsten and molybdenum.

  In the conductive layer X, nickel, boron, and the metal component M may be alloyed. In the conductive layer X, nickel and boron may be alloyed, nickel and the metal component M may be alloyed, or boron and the metal component M may be alloyed. In the conductive layer X, in addition to nickel, boron, and the metal component M, chromium or seaborgium may be used.

  Moreover, in the conductive particles having a nickel conductive layer that does not contain both tungsten and molybdenum, the hardness tends to be relatively low at the initial compression stage of the nickel conductive layer that does not contain both tungsten and molybdenum. For this reason, at the time of the connection between electrodes, the effect which eliminates the oxide film on the surface of an electrode and electroconductive particle becomes small, and there exists a tendency for the effect which makes connection resistance low.

  On the other hand, if the thickness of the nickel conductive layer that does not contain both tungsten and molybdenum is increased in order to obtain the effect of lowering the connection resistance further, or to be suitable for applications in which a large current flows, conductive objects may cause connection. The member or the substrate tends to be easily damaged. As a result, the conduction reliability between the electrodes in the connection structure tends to be low.

  On the other hand, since the conductive layer X contains nickel and at least one metal component M of tungsten and molybdenum, it is easy to make the 5% K value equal to or more than the lower limit. Further, the conductive layer X may be appropriately cracked when the conductive particles exceed 10% of the particle diameter of the conductive particles before compression in the compression direction and are compressed at 25% or less. Easy. When cracks occur when compressed appropriately, damage to the electrodes is less likely to occur, and therefore the connection resistance between the electrodes is further reduced.

  Further, since the conductive layer X includes nickel and at least one metal component M of tungsten and molybdenum, the conductive layer X has an appropriate hardness, and therefore compresses the conductive particles. When the electrodes are connected, an appropriate indentation can be formed on the electrodes. The indentation formed on the electrode is a concave portion of the electrode formed by pressing the electrode with conductive particles.

The conductive layer X preferably contains nickel as a main component. From the viewpoint of effectively reducing the initial connection resistance between the electrodes, it is better that the content of nickel in 100% by weight of the entire conductive layer X is larger. Therefore, the content of nickel is preferably 50% by weight or more, more preferably 60% by weight or more, still more preferably 70% by weight or more, and further preferably 75% by weight or more, in 100% by weight of the entire conductive layer X. Even more preferably, it is 80% by weight or more, particularly preferably 85% by weight or more, still more preferably 90% by weight or more, and most preferably 95% by weight or more. The content of nickel in 100% by weight of the entire conductive layer X may be 97% by weight or more, 97.5% by weight or more, or 98% by weight or more. When the nickel content is not less than the lower limit, the connection resistance between the electrodes is further reduced. Moreover, when there are few oxide films in the surface of an electrode or a conductive layer, there exists a tendency for the connection resistance between electrodes to become low, so that there is much content of the said nickel.

  The upper limit of the nickel content can be appropriately changed depending on the content of boron and the metal component M. The content of nickel in 100% by weight of the entire conductive layer X is preferably 99.9% by weight or less, more preferably 99.85% by weight or less, still more preferably 99.7% by weight or less, and particularly preferably 99.% by weight. Less than 45% by weight.

  Conductive particles having a nickel conductive layer that does not contain boron are relatively soft at the initial compression stage of the nickel conductive layer that does not contain boron, and the oxide film on the surface of the electrode and conductive particles is eliminated when the electrodes are connected. The effect tends to be small, and the effect of reducing the connection resistance tends to be small. In addition, the conductive layer may contain phosphorus instead of boron. In the conductive particles having a conductive layer containing nickel and phosphorus, the effect of eliminating the oxide film on the surface of the electrode and the conductive particles tends to be small, and the effect of reducing the connection resistance tends to be small.

  On the other hand, the thickness of the conductive layer not containing boron or the thickness of the conductive layer containing nickel and phosphorus is increased in order to obtain the effect of lowering the connection resistance or to be suitable for applications in which a large current flows. If the thickness is increased, the connection target member or the substrate tends to be easily damaged by the conductive particles. As a result, the conduction reliability between the electrodes in the connection structure tends to be low.

  On the other hand, since the conductive layer X contains boron, it is easy to make the 5% K value equal to or higher than the lower limit. Further, the conductive layer X may be appropriately cracked when the conductive particles exceed 10% of the particle diameter of the conductive particles before compression in the compression direction and are compressed at 25% or less. Easy. In addition, since the conductive layer X contains nickel, boron, and the metal component M, it is even easier to set the 5% K value to the lower limit or more. Furthermore, when the conductive particles are compressed at more than 10% of the particle diameter of the conductive particles before compression in the compression direction and less than 25%, the conductive layer X is more appropriately cracked. Is easy. When cracks occur when compressed appropriately, damage to the electrodes is less likely to occur, and therefore the connection resistance between the electrodes is further reduced.

  Further, since the conductive layer X contains boron, the conductive layer X has an appropriate hardness, so that the electrode is more unlikely to be damaged, and therefore the connection resistance between the electrodes is further reduced. Furthermore, since the conductive layer X contains boron, the conductive layer X has an appropriate hardness, so that when the conductive particles are compressed to connect the electrodes, an appropriate indentation can be formed on the electrodes.

  In particular, since the conductive layer X contains nickel, boron, and the metal component M, it is possible to achieve a high compression elastic modulus. For this reason, the oxide film on the surface of the electrode and the conductive particle can be effectively eliminated at the initial stage of compression of the conductive particle at the time of connection between the electrodes, and the conductive particle is appropriately compressed at the time of connection between the electrodes. In this stage, the conductive layer X is cracked, so that damage to the electrode can be suppressed. As a result, the connection resistance between the electrodes in the resulting connection structure can be reduced, and the conduction reliability between the electrodes can be increased.

  The content of boron in 100% by weight of the conductive layer X is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, still more preferably 0.1% by weight or more, preferably 5% by weight. Below, more preferably 4% by weight or less, still more preferably 3% by weight or less, particularly preferably 2.5% by weight or less, and most preferably 2% by weight or less. When the boron content is not less than the above lower limit, the conductive layer X becomes harder, the oxide film on the surface of the electrode and conductive particles can be more effectively removed, and the connection resistance between the electrodes is further reduced. can do. When the boron content is not more than the above upper limit, the content of nickel and the metal component M is relatively increased, so that the connection resistance between the electrodes is lowered.

  Also, the surface of the conductive layer X containing nickel and boron has high magnetism, and when the electrodes are electrically connected, the electrodes adjacent to each other in the lateral direction are connected due to the influence of the conductive particles aggregated by magnetism. There is a tendency to be easily. Since the conductive layer X contains nickel, boron, and the metal component M, the magnetism of the surface of the conductive layer X is considerably low. For this reason, it can suppress that several electroconductive particle aggregates. Therefore, when the electrodes are electrically connected, it is possible to prevent the electrodes adjacent in the lateral direction from being connected by the aggregated conductive particles. That is, a short circuit between adjacent electrodes can be further prevented.

  Furthermore, since the conductive layer X contains the metal component M, the conductive layer X has an appropriate hardness. Therefore, when the conductive particles are compressed to connect the electrodes, an appropriate indentation is formed on the electrodes. it can. Furthermore, the conductive layer X contains at least one of tungsten and molybdenum, or contains boron, so that the conductive layer X is considerably hardened. As a result, the electrodes are connected by conductive particles. Even when an impact is applied to the structure, poor conduction is unlikely to occur. That is, the impact resistance of the connection structure can be increased.

  The content of the metal component M (total content of tungsten and molybdenum) in 100% by weight of the conductive layer X is preferably 0.01% by weight or more, more preferably 0.1% by weight or more. More preferably, it is 0.2% by weight or more, more preferably 0.5% by weight or more, still more preferably 1% by weight or more, particularly preferably more than 5% by weight, most preferably 10% by weight or more. When the content of the metal component M is equal to or more than the lower limit, the hardness of the outer surface of the conductive layer is further increased. For this reason, when the oxide film is formed on the surface of the electrode or the conductive layer, the oxide film on the surface of the electrode and the conductive particles can be effectively eliminated, and the resin component between the electrode and the conductive particles can be removed. It can be effectively eliminated, the connection resistance is lowered, and the impact resistance of the resulting connection structure is increased. Furthermore, when the content of the metal component M is equal to or more than the lower limit, the magnetism of the outer surface of the conductive layer X becomes weak and the plurality of conductive particles are difficult to aggregate. For this reason, the short circuit between electrodes can be suppressed effectively.

  The upper limit of the content of the metal component M in 100% by weight of the entire conductive layer X can be appropriately changed depending on the contents of nickel and boron. The content of the metal component M in the total 100% by weight of the conductive layer X is preferably 40% by weight or less, more preferably 30% by weight or less, still more preferably 25% by weight or less, and particularly preferably 20% by weight or less. It is.

  When the conductive layer X contains tungsten, the content of tungsten in 100% by weight of the conductive layer X is preferably 0.01% by weight or more, more preferably 0.1% by weight or more. More preferably 0.2% by weight or more, more preferably 0.5% by weight or more, still more preferably 1% by weight or more, particularly preferably more than 5% by weight, most preferably 10% by weight or more, preferably 40% by weight. % Or less, more preferably 30% by weight or less, still more preferably 25% by weight or less, and particularly preferably 20% by weight or less. When the conductive layer X contains molybdenum, the content of molybdenum in the total 100% by weight of the conductive layer X is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and even more preferably. Is 0.2% by weight or more, more preferably 0.5% by weight or more, still more preferably 1% by weight or more, particularly preferably more than 5% by weight, most preferably 10% by weight or more, preferably 40% by weight or less. More preferably, it is 30% by weight or less, further preferably 25% by weight or less, and particularly preferably 20% by weight or less.

  From the viewpoint of effectively reducing the initial connection resistance between the electrodes, it is better that the total content of the nickel and the metal component M in 100% by weight of the conductive layer X is larger. Therefore, the total content of nickel and the metal component M is preferably 75.1% by weight or more, more preferably 80.1% by weight or more, and still more preferably 85.% by weight in the total 100% by weight of the conductive layer X. 1% by weight or more, particularly preferably 90.1% by weight or more, most preferably 95.1% by weight or more. The total content of nickel and the metal component M in 100% by weight of the entire conductive layer X may be 97.1% by weight or more, 97.6% by weight or more, and 98. It may be 1% by weight or more.

  From the viewpoint of further reducing the connection resistance between the electrodes, the conductive layer X does not contain phosphorus, or the conductive layer X contains phosphorus, and the content of phosphorus in 100% by weight of the conductive layer X as a whole. Is preferably less than 1% by weight. From the viewpoint of further reducing the connection resistance between the electrodes, the conductive layer X does not contain phosphorus, or the conductive layer X contains phosphorus, and the content of phosphorus in 100% by weight of the conductive layer X as a whole. Is more preferably less than 0.5% by weight. From the viewpoint of further effectively reducing the connection resistance between the electrodes, the content of phosphorus in 100% by weight of the entire conductive layer X is more preferably 0.3% by weight or less, still more preferably 0.1% by weight. % Or less. When the phosphorus content is less than or equal to the above upper limit, the oxide film on the surfaces of the electrodes and the conductive particles can be more effectively eliminated when connecting the electrodes. As a result, the connection resistance between the electrodes can be lowered. Furthermore, since the resin component between the electrode and the conductive particles can be effectively eliminated, the connection resistance between the electrodes is further reduced. Since the connection resistance between the electrodes becomes considerably low, the conductive layer X particularly preferably does not contain phosphorus.

  In particular, when the conductive layer X includes the metal component M and the phosphorus content is not more than the upper limit, and the conductive layer X has protrusions on the outer surface, the surface of the electrode and the conductive particles The oxide film can be more effectively eliminated, the resin component between the electrode and the conductive particles can be effectively eliminated, and the connection resistance can be further reduced.

  Furthermore, as a result of the conductive layer X containing the metal component M and the phosphorus content being not more than the above upper limit, the conductive layer X is considerably hardened. As a result, the connection structure in which the electrodes are connected by conductive particles Even if an impact is applied to this, poor conduction is unlikely to occur. That is, the impact resistance of the connection structure can be increased.

  The method for measuring the contents of nickel, boron, tungsten, molybdenum and phosphorus in the conductive layer X is not particularly limited, and various known analysis methods can be used. Examples of this measuring method include absorption spectrometry or spectrum analysis. In the above-mentioned absorption analysis method, a flame absorptiometer, an electric heating furnace absorptiometer, or the like can be used. Examples of the spectrum analysis method include a plasma emission analysis method and a plasma ion source mass spectrometry method.

  When measuring the contents of nickel, boron, tungsten, molybdenum and phosphorus in the conductive layer X, it is preferable to use an ICP emission spectrometer. Examples of commercially available ICP emission analyzers include ICP emission analyzers manufactured by HORIBA. Moreover, when measuring each content of nickel, boron, tungsten, molybdenum and phosphorus in the conductive layer X, an ICP-MS analyzer may be used.

  The metal for forming the other conductive layer (second conductive layer) is not particularly limited. Examples of the metal include gold, silver, copper, palladium, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, thallium, germanium, cadmium, silicon, and tungsten. And alloys thereof. Examples of the metal include tin-doped indium oxide (ITO) and solder. Especially, since the connection resistance between electrodes becomes still lower, an alloy containing tin, nickel, palladium, copper or gold is preferable, and nickel or palladium is more preferable. The metal constituting the other conductive layer preferably contains nickel.

  The method for forming a conductive layer (another conductive layer and conductive layer X) on the surface of the substrate particle is not particularly limited. As a method for forming the conductive layer, for example, a method by electroless plating, a method by electroplating, a method by physical vapor deposition, and a paste containing metal powder or metal powder and a binder is used for base particles or other conductive layers. For example, a method of coating the surface. Especially, since formation of a conductive layer is simple, the method by electroless plating is preferable. Examples of the method by physical vapor deposition include methods such as vacuum vapor deposition, ion plating, and ion sputtering.

  The particle diameter of the conductive particles is preferably 0.1 μm or more, more preferably 0.5 μm or more, further preferably 1 μm or more, particularly preferably 2 μm or more, preferably 1000 μm or less, more preferably 500 μm or less, and even more preferably. Is not more than 300 μm, more preferably not more than 100 μm, still more preferably not more than 50 μm, particularly preferably not more than 30 μm, still more particularly preferably not more than 20 μm, most preferably not more than 5 μm. When the particle diameter of the conductive particles is not less than the above lower limit and not more than the above upper limit, the contact area between the conductive particles and the electrodes is sufficiently large when the electrodes are connected using the conductive particles, and the conductive layer When forming the conductive particles, it becomes difficult to form aggregated conductive particles. Further, the distance between the electrodes connected via the conductive particles does not become too large, and the conductive layer is difficult to peel from the surface of the base material particles.

  The particle diameter of the conductive particles when used for a conductive material such as an anisotropic conductive material is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 100 μm or less, more preferably 20 μm or less. When the particle diameter of the conductive particles is not less than the above lower limit and not more than the above upper limit, the contact area between the conductive particles and the electrodes is sufficiently large when the electrodes are connected using the conductive particles, and the conductive layer When forming the conductive particles, it becomes difficult to form aggregated conductive particles. Further, the distance between the electrodes connected via the conductive particles does not become too large, and the conductive layer is difficult to peel from the surface of the base material particles.

  The particle diameter of the conductive particles indicates the diameter when the conductive particles are true spherical, and indicates the maximum diameter when the conductive particles are not true spherical.

  The thickness of the conductive layer X is preferably 0.005 μm or more, more preferably 0.01 μm or more, still more preferably 0.05 μm or more, preferably 1 μm or less, more preferably 0.3 μm or less. When the thickness of the conductive layer X is not less than the above lower limit and not more than the above upper limit, sufficient conductivity can be obtained, and the conductive particles do not become too hard, and the conductive particles are sufficiently bonded at the time of connection between the electrodes. Deform.

  When the conductive layer has a laminated structure of two or more layers, the thickness of the conductive layer X is preferably 0.001 μm or more, more preferably 0.01 μm or more, still more preferably 0.05 μm or more, preferably 0.5 μm or less. More preferably, it is 0.3 μm or less, and further preferably 0.1 μm or less. When the thickness of the conductive layer X is not less than the above lower limit and not more than the above upper limit, the coating with the conductive layer X can be made uniform, and the connection resistance between the electrodes becomes sufficiently low.

  When the conductive layer has a laminated structure of two or more layers, the total thickness of the conductive layer including the conductive layer X is preferably 0.001 μm or more, more preferably 0.01 μm or more, still more preferably 0.05 μm or more, particularly It is preferably 0.1 μm or more, preferably 1 μm or less, more preferably 0.5 μm or less, still more preferably 0.3 μm or less, and still more preferably 0.1 μm or less. When the thickness of the entire conductive layer is not less than the above lower limit and not more than the above upper limit, the covering of the entire conductive layer can be made uniform, and the connection resistance between the electrodes becomes sufficiently low.

  The thickness of the conductive layer X is particularly preferably 0.05 μm or more and 0.5 μm or less. Furthermore, it is particularly preferable that the particle diameter of the base particle is 2 μm or more and 5 μm or less, and the thickness of the conductive layer X is 0.05 μm or more and 0.5 μm or less. The thickness of the conductive layer X is most preferably 0.05 μm or more and 0.3 μm or less. Furthermore, it is most preferable that the particle diameter of the substrate particles is 2 μm or more and 5 μm or less, and the thickness of the conductive layer X is 0.05 μm or more and 0.3 μm or less. When these preferable thicknesses of the conductive layer X and the particle diameters of the base particles are satisfied, the conductive particles can be suitably used for applications in which a large current flows. Furthermore, when the conductive particles are compressed to connect the electrodes, it is possible to further suppress the electrodes from being damaged.

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

  As a method of controlling the content of nickel, tungsten, molybdenum, boron and phosphorus in the conductive layer X, for example, a method of controlling the pH of the nickel plating solution when forming the conductive layer X by electroless nickel plating, When forming the conductive layer X by electroless nickel plating, a method of adjusting the concentration of the boron-containing reducing agent, a method of adjusting the tungsten concentration in the nickel plating solution, a method of adjusting the molybdenum concentration in the nickel plating solution, and nickel Examples include a method of adjusting the nickel salt concentration in the plating solution.

  In the method of forming by electroless plating, generally, a catalyzing step and an electroless plating step are performed. Hereinafter, an example of a method for forming an alloy plating layer containing at least one of nickel, tungsten, and molybdenum and boron on the surface of the resin particles by electroless plating will be described.

  In the catalyzing step, a catalyst serving as a starting point for forming a plating layer by electroless plating is formed on the surface of the resin particles.

  As a method of forming the catalyst on the surface of the resin particles, for example, after adding the resin particles to a solution containing palladium chloride and tin chloride, the surface of the resin particles is activated with an acid solution or an alkali solution, A method of depositing palladium on the surface of the resin particles, and after adding the resin particles to a solution containing palladium sulfate and aminopyridine, the surface of the resin particles is activated by a solution containing a reducing agent. Examples thereof include a method of depositing palladium on the surface. As the reducing agent, a boron-containing reducing agent is preferably used. However, a phosphorus-containing reducing agent such as sodium hypophosphite may be used as the reducing agent.

  In the electroless plating step, a nickel plating bath containing a nickel salt, at least one of a tungsten-containing compound and a molybdenum-containing compound, and the boron-containing reducing agent is used. By immersing the resin particles in the nickel plating bath, nickel can be deposited on the surface of the resin particles on which the catalyst is formed, and a conductive layer containing nickel, boron, and the metal component M can be formed. .

  Examples of the tungsten-containing compound include tungsten boride and sodium tungstate.

  Examples of the molybdenum-containing compound include molybdenum boride and sodium molybdate.

  Examples of the boron-containing reducing agent include dimethylamine borane, sodium borohydride, and potassium borohydride.

  The conductive particles according to the present invention preferably have protrusions on the surface. The conductive layer including the conductive layer X preferably has protrusions on the outer surface, and the conductive layer X preferably has protrusions on the outer surface. An oxide film is often formed on the surface of the electrode connected by the conductive particles. Furthermore, an oxide film is often formed on the surface of the conductive layer of the conductive particles. By using the conductive particles having protrusions, the oxide film is effectively eliminated by the protrusions by placing the conductive particles between the electrodes and then pressing them. For this reason, an electrode and electroconductive particle can be contacted still more reliably and the connection resistance between electrodes can be made low. Further, when the conductive particles have an insulating material on the surface, or when the conductive particles are dispersed in a binder resin and used as a conductive material, the protrusion between the conductive particles and the electrode is caused by the protrusion of the conductive particles. Resin can be effectively eliminated. For this reason, the conduction | electrical_connection reliability between electrodes becomes high.

  It is preferable that there are a plurality of protrusions. The number of protrusions on the outer surface of the conductive layer per one conductive particle is preferably 3 or more, more preferably 5 or more. The upper limit of the number of protrusions is not particularly limited. The upper limit of the number of protrusions can be appropriately selected in consideration of the particle diameter of the conductive particles.

[Core material]
Since the core substance is embedded in the conductive layer, it is easy for the conductive layer to have a plurality of protrusions on the outer surface. However, in order to form protrusions on the surfaces of the conductive particles and the conductive layer, the core substance is not necessarily used.

  As the method for forming the protrusions, a core material is attached to the surface of the base particle, and then a conductive layer is formed by electroless plating, and a conductive layer is formed on the surface of the base particle by electroless plating. Thereafter, a method of attaching a core substance and further forming a conductive layer by electroless plating may be used.

  As a method for disposing the core substance on the surface of the base particle, for example, a conductive substance that becomes the core substance is added to the dispersion of the base particle, and the core substance is added to the surface of the base particle, for example, , A method of accumulating and adhering by van der Waals force, and adding a conductive substance as a core substance to the container containing the base particle, and applying mechanical action such as rotation of the container to the surface of the base particle. Examples include a method of attaching a core substance. Especially, since the quantity of the core substance to adhere is easy to control, the method of making a core substance accumulate and adhere on the surface of the base particle in a dispersion liquid is preferable.

  Examples of the conductive material constituting the core material include conductive non-metals such as metals, metal oxides, and graphite, and conductive polymers. Examples of the conductive polymer include polyacetylene. Among them, metal is preferable because conductivity can be increased and connection resistance can be effectively reduced. The core substance is preferably metal particles.

  Examples of the metal include gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium and cadmium, and tin-lead. Examples include alloys composed of two or more metals such as alloys, tin-copper alloys, tin-silver alloys, and tin-lead-silver alloys. Of these, nickel, copper, silver or gold is preferable. The metal constituting the core material may be the same as or different from the metal constituting the conductive layer. The metal constituting the core material preferably includes a metal constituting the conductive layer. It is preferable that the metal which comprises the said core substance contains nickel. It is preferable that the metal which comprises the said core substance contains nickel.

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

  The average diameter (average particle diameter) of the core substance is preferably 0.001 μm or more, more preferably 0.05 μm or more, preferably 0.9 μm or less, more preferably 0.2 μm or less. When the average diameter of the core substance is not less than the above lower limit and not more than the above upper limit, the connection resistance between the electrodes can be effectively reduced.

  The “average diameter (average particle diameter)” of the core substance indicates a number average diameter (number average particle diameter). The average diameter of the core material is obtained by observing 50 arbitrary core materials with an electron microscope or an optical microscope and calculating an average value.

[Insulating material]
The conductive particles according to the present invention preferably include an insulating material disposed on the surface of the conductive layer. In this case, when the conductive particles are used for connection between the electrodes, a short circuit between adjacent electrodes can be prevented. Specifically, when a plurality of conductive particles are in contact with each other, an insulating material is present between the plurality of electrodes, so that it is possible to prevent a short circuit between electrodes adjacent in the lateral direction instead of between the upper and lower electrodes. Note that when the conductive particles are pressurized with the two electrodes at the time of connection between the electrodes, the insulating substance between the conductive layer of the conductive particles and the electrodes can be easily excluded. Since the conductive particles have a plurality of protrusions on the outer surface of the conductive layer, the insulating material between the conductive layer of the conductive particles and the electrode can be easily excluded.

  It is preferable that the insulating material is an insulating particle because the insulating material can be more easily removed when the electrodes are pressed.

  Specific examples of the insulating resin that is the material of the insulating material include polyolefins, (meth) acrylate polymers, (meth) acrylate copolymers, block polymers, thermoplastic resins, crosslinked thermoplastic resins, and thermosetting. Resin, water-soluble resin, and the like.

  Examples of the polyolefins include polyethylene, ethylene-vinyl acetate copolymer, and ethylene-acrylic acid ester copolymer. Examples of the (meth) acrylate polymer include polymethyl (meth) acrylate, polyethyl (meth) acrylate, and polybutyl (meth) acrylate. Examples of the block polymer include polystyrene, styrene-acrylic acid ester copolymer, SB type styrene-butadiene block copolymer, SBS type styrene-butadiene block copolymer, and hydrogenated products thereof. Examples of the thermoplastic resin include vinyl polymers and vinyl copolymers. As said thermosetting resin, an epoxy resin, a phenol resin, a melamine resin, etc. are mentioned. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinyl pyrrolidone, polyethylene oxide, and methyl cellulose. Of these, water-soluble resins are preferable, and polyvinyl alcohol is more preferable.

  Examples of a method for disposing an insulating material on the surface of the conductive layer include a chemical method and a physical or mechanical method. Examples of the chemical method include an interfacial polymerization method, a suspension polymerization method in the presence of particles, and an emulsion polymerization method. Examples of the physical or mechanical method include spray drying, hybridization, electrostatic adhesion, spraying, dipping, and vacuum deposition. In particular, since the insulating substance is difficult to be detached, a method of disposing the insulating substance on the surface of the conductive layer through a chemical bond is preferable.

  The average diameter (average particle diameter) of the insulating material can be appropriately selected depending on the particle diameter of the conductive particles, the use of the conductive particles, and the like. The average diameter (average particle diameter) of the insulating material is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 1 μm or less, more preferably 0.5 μm or less. When the average diameter of the insulating material is not less than the above lower limit, the conductive layers of the plurality of conductive particles are difficult to contact when the conductive particles are dispersed in the binder resin. When the average diameter of the insulating particles is not more than the above upper limit, it is not necessary to make the pressure too high in order to eliminate the insulating material between the electrodes and the conductive particles when the electrodes are connected. There is no need for heating.

  The “average diameter (average particle diameter)” of the insulating material indicates a number average diameter (number average particle diameter). The average diameter of the insulating material is obtained using a particle size distribution measuring device or the like.

(Conductive material)
The conductive material according to the present invention includes the conductive particles described above and a binder resin. The conductive particles according to the present invention are preferably added to a binder resin and used as a conductive material. The conductive material according to the present invention is preferably an anisotropic conductive material.

  The binder resin is not particularly limited. As the binder resin, a known insulating resin is used. Examples of the binder resin include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, and elastomers. As for the said binder resin, only 1 type may be used and 2 or more types may be used together.

  Examples of the vinyl resin include vinyl acetate resin, acrylic resin, and styrene resin. Examples of the thermoplastic resin include polyolefin resins, ethylene-vinyl acetate copolymers, and polyamide resins. Examples of the curable resin include an epoxy resin, a urethane resin, a polyimide resin, and an unsaturated polyester resin. 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 a styrene-butadiene-styrene block copolymer, a styrene-isoprene-styrene block copolymer, a hydrogenated product of a styrene-butadiene-styrene block copolymer, and a styrene-isoprene. -Hydrogenated product of a styrene block copolymer. Examples of the elastomer include styrene-butadiene copolymer rubber and acrylonitrile-styrene block copolymer rubber.

  In addition to the conductive particles and the binder resin, the conductive material includes, for example, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, and a light stabilizer. Various additives such as an agent, an ultraviolet absorber, a lubricant, an antistatic agent and a flame retardant may be contained.

  The method for dispersing the conductive particles in the binder resin is not particularly limited, and a conventionally known dispersion method can be used. Examples of a method for dispersing the conductive particles in the binder resin include a method in which the conductive particles are added to the binder resin and then kneaded and dispersed with a planetary mixer or the like. The conductive particles are dispersed in water. Alternatively, after uniformly dispersing in an organic solvent using a homogenizer or the like, it is added to the binder resin and kneaded with a planetary mixer or the like, and the binder resin is diluted with water or an organic solvent. Then, the method of adding the said electroconductive particle, kneading with a planetary mixer etc. and disperse | distributing is mentioned.

  The conductive material according to the present invention can be used as a conductive paste and a conductive film. When the conductive material according to the present invention is used as a film-like adhesive such as a conductive film, a film-like adhesive containing no conductive particles is added to the film-like adhesive containing the conductive particles. It may be laminated. The conductive paste is preferably an anisotropic conductive paste. The conductive film is preferably an anisotropic conductive film.

  In 100% by weight of the conductive material, the content of the binder resin is preferably 10% by weight or more, more preferably 30% by weight or more, still more preferably 50% by weight or more, particularly preferably 70% by weight or more, preferably 99.% or more. It is 99 weight% or less, More preferably, it is 99.9 weight% or less. When the content of the binder resin is not less than the above lower limit and not more than the above upper limit, the conductive particles are efficiently arranged between the electrodes, and the connection reliability of the connection target member connected by the conductive material is further increased.

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

(Connection structure)
A connection structure can be obtained by connecting the connection target members using the conductive particles of the present invention or using a conductive material containing the conductive particles and a binder resin.

  The connection structure includes a first connection target member, a second connection target member, and a connection portion connecting the first and second connection target members, and the connection portion is a conductive member of the present invention. It is preferable that the connection structure be formed of conductive particles or formed of a conductive material containing the conductive particles and a binder resin. In the case where conductive particles are used, the connection portion itself is conductive particles. That is, the first and second connection target members are connected by the conductive particles. The conductive material used for obtaining the connection structure is preferably an anisotropic conductive material.

  In FIG. 4, the connection structure using the electroconductive particle which concerns on the 1st Embodiment of this invention is typically shown with front sectional drawing.

  4 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. Prepare. The connection portion 54 is formed by curing a conductive material including the conductive particles 1. In FIG. 4, the conductive particles 1 are schematically shown for convenience of illustration.

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

The manufacturing method of the connection structure is not particularly limited. As an example of the manufacturing method of the connection structure, the conductive material is disposed between the first connection target member and the second connection target member to obtain a laminate, and then the laminate is heated and pressurized. Methods and the like. The pressure of the said pressurization is about 9.8 * 10 < ⁴ > -4.9 * 10 < ⁶ > Pa. The temperature of the said heating is about 120-220 degreeC.

  Specific examples of the connection target member include electronic components such as semiconductor chips, capacitors, and diodes, and circuit boards such as printed boards, flexible printed boards, and glass boards. The conductive material is preferably a conductive material for connecting electronic components. The conductive material is a paste-like conductive paste, and is preferably applied on the connection target member in a paste-like state.

  Examples of the electrode provided on the connection target member include metal electrodes such as a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a molybdenum electrode, and a tungsten electrode. When the connection object member is a flexible printed board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, or a copper electrode. When the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, or a tungsten electrode. In addition, when the said electrode is an aluminum electrode, the electrode formed only with aluminum may be sufficient and the electrode by which the aluminum layer was laminated | stacked on the surface of the metal oxide layer may be sufficient. Examples of the material for 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.

  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.

Example 1
Divinylbenzene copolymer resin particles having a particle size of 3.0 μm (“Micropearl SP-203” manufactured by Sekisui Chemical Co., Ltd.) were prepared.

  After dispersing 10 parts by weight of the resin particles in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, the resin particles were taken out by filtering the solution. Next, the resin particles were added to 100 parts by weight of a 1% by weight dimethylamine borane solution to activate the surface of the resin particles. The resin particles whose surface was activated were sufficiently washed with water, and then added to 500 parts by weight of distilled water and dispersed to obtain a suspension.

  Further, a nickel plating solution (pH 8.5) containing 0.23 mol / L of nickel sulfate, 0.92 mol / L of dimethylamine borane, 0.5 mol / L of sodium citrate and 0.01 mol / L of sodium tungstate was prepared.

  While stirring the obtained suspension at 60 ° C., the nickel plating solution was gradually added dropwise to the suspension to perform electroless nickel plating. Thereafter, by filtering the suspension, the particles are taken out, washed with water, and dried to obtain conductive particles having a nickel-boron-tungsten conductive layer (thickness 0.1 μm) disposed on the surface of the resin particles. It was.

(Example 2)
Conductive particles having a nickel-boron-tungsten conductive layer (thickness 0.1 μm) disposed on the surface of the resin particles are the same as in Example 1 except that the sodium tungstate concentration is changed to 0.12 mol / L. Obtained.

(Example 3)
Conductive particles having a nickel-boron-tungsten conductive layer (thickness 0.1 μm) disposed on the surface of the resin particles are the same as in Example 1 except that the sodium tungstate concentration is changed to 0.23 mol / L. Obtained.

Example 4
Conductive particles having a nickel-boron-tungsten conductive layer (thickness 0.1 μm) disposed on the surface of the resin particles are the same as in Example 1 except that the sodium tungstate concentration is changed to 0.35 mol / L. Obtained.

(Example 5)
Nickel-boron-tungsten was formed on the surface of the resin particles in the same manner as in Example 1 except that the dimethylamine borane concentration was changed to 2.76 mol / L and the sodium tungstate concentration was changed to 0.35 mol / L. Conductive particles having a conductive layer (thickness 0.1 μm) were obtained.

(Example 6)
(1) Palladium adhesion process The divinylbenzene resin particle ("Micropearl SP-205" by Sekisui Chemical Co., Ltd.) whose particle diameter is 5.0 micrometers was prepared. The resin particles were etched and washed with water. Next, resin particles were added to 100 mL of a palladium-catalyzed solution containing 8% by weight of a palladium catalyst and stirred. Then, it filtered and wash | cleaned. Resin particles were added to 0.5 wt% dimethylamine borane solution at pH 6 to obtain resin particles to which palladium was attached.

(2) Core substance adhesion step The resin particles to which palladium was adhered were stirred and dispersed in 300 mL of ion exchange water for 3 minutes to obtain a dispersion. Next, 1 g of metallic nickel particle slurry (average particle diameter 100 nm) was added to the dispersion over 3 minutes to obtain resin particles to which the core substance was adhered.

(3) Electroless nickel plating step In the same manner as in Example 1, conductive particles were obtained in which a nickel-boron-tungsten conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles.

(Example 7)
Conductive particles in which a nickel-boron-tungsten conductive layer (thickness: 0.1 μm) is arranged on the surface of the resin particles are the same as in Example 6 except that the sodium tungstate concentration is changed to 0.35 mol / L. Obtained.

(Example 8)
(1) Production of insulating particles A 1000 mL separable flask equipped with a four-neck separable cover, a stirring blade, a three-way cock, a condenser tube and a temperature probe was charged with 100 mmol methyl methacrylate and N, N, N-trimethyl. Ion-exchanged water containing a monomer composition containing 1 mmol of -N-2-methacryloyloxyethylammonium chloride and 1 mmol of 2,2'-azobis (2-amidinopropane) dihydrochloride so that the solid content is 5% by weight. Then, the mixture was stirred at 200 rpm and polymerized at 70 ° C. for 24 hours under a nitrogen atmosphere. After completion of the reaction, it was freeze-dried to obtain insulating particles having an ammonium group on the surface, an average particle size of 220 nm, and a CV value of 10%.

  The insulating particles were dispersed in ion exchange water under ultrasonic irradiation to obtain a 10 wt% aqueous dispersion of insulating particles.

  10 g of the conductive particles obtained in Example 6 were dispersed in 500 mL of ion exchange water, 4 g of an aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 6 hours. After filtration through a 3 μm mesh filter, the particles were further washed with methanol and dried to obtain conductive particles having insulating particles attached thereto.

  When observed with a scanning electron microscope (SEM), only one coating layer of insulating particles was formed on the surface of the conductive particles. The coverage of the insulating particles with respect to the area of 2.5 μm from the center of the conductive particles by image analysis (that is, the projected area of the particle diameter of the insulating particles) was calculated to be 30%.

Example 9
Conductive particles in which a nickel-boron-tungsten conductive layer (thickness: 0.1 μm) is disposed on the surface of the resin particles are the same as in Example 1 except that the sodium tungstate concentration is changed to 0.46 mol / L. Obtained.

(Example 10)
Nickel-boron-tungsten was formed on the surface of the resin particles in the same manner as in Example 1 except that the dimethylamine borane concentration was changed to 4.60 mol / L and the sodium tungstate concentration was changed to 0.23 mol / L. Conductive particles having a conductive layer (thickness 0.1 μm) were obtained.

(Comparative Example 1)
In the same manner as in Example 1 except that 0.92 mol / L of dimethylamine borane in the nickel plating solution was changed to 0.5 mol / L of sodium hypophosphite, nickel, tungsten and phosphorus were added to the surface of the resin particles. The electroconductive particle by which the electroconductive layer (thickness 0.1 micrometer) containing was arrange | positioned was obtained. The phosphorus content in the entire conductive layer of 100% by weight was 8.9% by weight.

(Comparative Example 2)
A conductive layer (thickness: 0.1 μm) containing nickel and boron was disposed on the surface of the resin particles in the same manner as in Example 1 except that 0.01 mol / L of sodium tungstate in the nickel plating solution was not used. Conductive particles were obtained.

(Example 11)
Divinylbenzene copolymer resin particles having a particle size of 3.0 μm (“Micropearl SP-203” manufactured by Sekisui Chemical Co., Ltd.) were prepared.

  After dispersing 10 parts by weight of the resin particles in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, the resin particles were taken out by filtering the solution. Next, the resin particles were added to 100 parts by weight of a 1% by weight dimethylamine borane solution to activate the surface of the resin particles. The resin particles whose surface was activated were sufficiently washed with water, and then added to 500 parts by weight of distilled water and dispersed to obtain a suspension.

  Further, a nickel plating solution (pH 8.5) containing 0.23 mol / L of nickel sulfate, 0.92 mol / L of dimethylamine borane, 0.5 mol / L of sodium citrate and 0.01 mol / L of sodium molybdate was prepared.

  While stirring the obtained suspension at 60 ° C., the nickel plating solution was gradually added dropwise to the suspension to perform electroless nickel plating. Thereafter, by filtering the suspension, the particles are taken out, washed with water, and dried to obtain conductive particles having a nickel-boron-molybdenum conductive layer (thickness 0.1 μm) disposed on the surface of the resin particles. It was.

(Example 12)
Conductive particles in which a nickel-boron-molybdenum conductive layer (thickness 0.1 μm) is arranged on the surface of the resin particles are the same as in Example 11 except that the sodium molybdate concentration is changed to 0.12 mol / L. Obtained.

(Example 13)
Conductive particles having a nickel-boron-molybdenum conductive layer (thickness 0.1 μm) disposed on the surface of the resin particles are the same as in Example 11 except that the sodium molybdate concentration is changed to 0.23 mol / L. Obtained.

(Example 14)
Conductive particles in which a nickel-boron-molybdenum conductive layer (thickness 0.1 μm) is arranged on the surface of the resin particles are the same as in Example 11 except that the sodium molybdate concentration is changed to 0.35 mol / L. Obtained.

(Example 15)
Nickel-boron-molybdenum was formed on the surface of the resin particles in the same manner as in Example 11 except that the dimethylamine borane concentration was changed to 2.76 mol / L and the sodium molybdate concentration was changed to 0.35 mol / L. Conductive particles having a conductive layer (thickness 0.1 μm) were obtained.

(Example 16)
(1) Palladium adhesion process The divinylbenzene resin particle ("Micropearl SP-205" by Sekisui Chemical Co., Ltd.) whose particle diameter is 5.0 micrometers was prepared. The resin particles were etched and washed with water. Next, resin particles were added to 100 mL of a palladium-catalyzed solution containing 8% by weight of a palladium catalyst and stirred. Then, it filtered and wash | cleaned. Resin particles were added to 0.5 wt% dimethylamine borane solution at pH 6 to obtain resin particles to which palladium was attached.

(2) Core substance adhesion step The resin particles to which palladium was adhered were stirred and dispersed in 300 mL of ion exchange water for 3 minutes to obtain a dispersion. Next, 1 g of metallic nickel particle slurry (average particle diameter 100 nm) was added to the dispersion over 3 minutes to obtain resin particles to which the core substance was adhered.

(3) Electroless nickel plating step In the same manner as in Example 11, conductive particles in which a nickel-boron-molybdenum conductive layer (thickness: 0.1 μm) was arranged on the surface of the resin particles were obtained.

(Example 17)
Conductive particles having a nickel-boron-molybdenum conductive layer (thickness 0.1 μm) disposed on the surface of the resin particles are the same as in Example 16 except that the sodium molybdate concentration was changed to 0.35 mol / L. Obtained.

(Example 18)
(1) Production of insulating particles A 1000 mL separable flask equipped with a four-neck separable cover, a stirring blade, a three-way cock, a condenser tube and a temperature probe was charged with 100 mmol methyl methacrylate and N, N, N-trimethyl. Ion-exchanged water containing a monomer composition containing 1 mmol of -N-2-methacryloyloxyethylammonium chloride and 1 mmol of 2,2'-azobis (2-amidinopropane) dihydrochloride so that the solid content is 5% by weight. Then, the mixture was stirred at 200 rpm and polymerized at 70 ° C. for 24 hours under a nitrogen atmosphere. After completion of the reaction, it was freeze-dried to obtain insulating particles having an ammonium group on the surface, an average particle size of 220 nm, and a CV value of 10%.

  The insulating particles were dispersed in ion exchange water under ultrasonic irradiation to obtain a 10 wt% aqueous dispersion of insulating particles.

  10 g of the conductive particles obtained in Example 16 were dispersed in 500 mL of ion exchange water, 4 g of an aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 6 hours. After filtration through a 3 μm mesh filter, the particles were further washed with methanol and dried to obtain conductive particles having insulating particles attached thereto.

  When observed with a scanning electron microscope (SEM), only one coating layer of insulating particles was formed on the surface of the conductive particles. The coverage of the insulating particles with respect to the area of 2.5 μm from the center of the conductive particles by image analysis (that is, the projected area of the particle diameter of the insulating particles) was calculated to be 30%.

(Example 19)
Conductive particles in which a nickel-boron-molybdenum conductive layer (thickness: 0.1 μm) is arranged on the surface of the resin particles are the same as in Example 11 except that the sodium molybdate concentration is changed to 0.46 mol / L. Obtained.

(Example 20)
Nickel-boron-molybdenum was formed on the surface of the resin particles in the same manner as in Example 11 except that the dimethylamine borane concentration was changed to 4.60 mol / L and the sodium molybdate concentration was changed to 0.23 mol / L. Conductive particles having a conductive layer (thickness 0.1 μm) were obtained.

(Comparative Example 3)
In the same manner as in Example 11 except that 0.92 mol / L of dimethylamine borane in the nickel plating solution was changed to 0.5 mol / L of sodium hypophosphite, nickel, molybdenum and phosphorus were added to the surface of the resin particles. The electroconductive particle by which the electroconductive layer (thickness 0.1 micrometer) containing was arrange | positioned was obtained. The phosphorus content in the entire conductive layer of 100% by weight was 9.5% by weight.

(Evaluation of Examples 1-20 and Comparative Examples 1-3)
(1) Compressive elastic modulus of conductive particles (5% K value)
The compression modulus (5% K value) of the obtained conductive particles was measured using a micro compression tester (“Fischer Scope H-100” manufactured by Fischer).

(2) Conductive layer cracking test Conductive particles were placed on a table. Using a micro compression tester (“Fischerscope H-100” manufactured by Fischer), a cylinder (diameter 50 μm, made of diamond) as a compression member under the conditions of a compression speed of 0.33 mN / sec and a maximum test load of 10 mN, The smooth end surface of the compression member was lowered toward the conductive particles. The conductive particles were compressed by the smooth end face. Compression was performed until cracking occurred in the conductive layer of the conductive particles. Tables 1 and 2 below show the compression displacement of the conductive particles in which the conductive layer was cracked with respect to the particle diameter of the conductive particles before compression in the compression direction. Regarding the evaluation results of the compression displacement, the average values of the measured values of the three conductive particles are shown in Tables 1 and 2 below.

(3) Content of nickel, boron, phosphorus, tungsten and molybdenum in 100% by weight of the entire conductive layer X 5 g of conductive particles are added to a mixed solution of 5 mL of 60% nitric acid and 10 mL of 37% hydrochloric acid to form a conductive layer. Completely dissolved to obtain a solution. Using the obtained solution, the contents of nickel, boron, phosphorus, tungsten and molybdenum were analyzed with an ICP-MS analyzer (manufactured by Hitachi, Ltd.). In addition, the electroconductive layer in the electroconductive particle of an Example did not contain phosphorus.

(4) Plating state The plating state of 50 conductive particles obtained was observed with a scanning electron microscope. The presence or absence of plating unevenness such as plating cracking or plating peeling was observed. The case where the number of conductive particles in which plating unevenness was confirmed was 4 or less was judged as “good”, and the case where the number of conductive particles in which plating unevenness was confirmed was 5 or more was judged as “bad”.

(5) Aggregation state 10 parts by weight of bisphenol A type epoxy resin (“Epicoat 1009” manufactured by Mitsubishi Chemical Corporation), 40 parts by weight of acrylic rubber (weight average molecular weight of about 800,000), 200 parts by weight of methyl ethyl ketone, and microcapsule type curing 50 parts by weight of the agent (“HX3941HP” manufactured by Asahi Kasei Chemicals Co., Ltd.) and 2 parts by weight of the silane coupling agent (“SH6040” manufactured by Toray Dow Corning Silicone Co., Ltd.) are mixed to give a conductive particle content of 3% by weight. Thus, an anisotropic conductive material was obtained.

  The obtained anisotropic conductive material was stored at 25 ° C. for 72 hours. After storage, it was evaluated whether or not the conductive particles aggregated in the anisotropic conductive material were settled. The case where the aggregated conductive particles were not settled was judged as “good”, and the case where the aggregated conductive particles were settled was judged as “bad”.

(6) Connection resistance Fabrication of connection structure:
10 parts by weight of bisphenol A type epoxy resin (“Epicoat 1009” manufactured by Mitsubishi Chemical Corporation), 40 parts by weight of acrylic rubber (weight average molecular weight of about 800,000), 200 parts by weight of methyl ethyl ketone, and a microcapsule type curing agent (Asahi Kasei Chemicals) "HX3941HP" manufactured by HX3941) and 2 parts by weight of a silane coupling agent ("SH6040" manufactured by Toray Dow Corning Silicone Co., Ltd.) are mixed, and the conductive particles are added so that the content is 3% by weight. A resin composition was obtained by dispersing.

  The obtained resin composition was applied to a 50 μm-thick PET (polyethylene terephthalate) film whose one surface was released from the mold, and dried with hot air at 70 ° C. for 5 minutes to produce an anisotropic conductive film. The thickness of the obtained anisotropic conductive film was 12 μm.

  The obtained anisotropic conductive film was cut into a size of 5 mm × 5 mm. The cut anisotropic conductive film is formed of a glass substrate (width 3 cm, length 3 cm) having an aluminum electrode (height 0.2 μm, L / S = 20 μm / 20 μm) having a lead wire for resistance measurement on one side. Affixed almost at the center on the aluminum electrode side. Next, a two-layer flexible printed board (width 2 cm, length 1 cm) having the same aluminum electrode was bonded after being aligned so that the electrodes overlap each other. The laminated body of the glass substrate and the two-layer flexible printed circuit board was thermocompression bonded under pressure bonding conditions of 10 N, 180 ° C., and 20 seconds to obtain a connection structure. A two-layer flexible printed board in which an aluminum electrode is directly formed on a polyimide film was used.

Connection resistance measurement:
The connection resistance between the opposing electrodes of the obtained connection structure was measured by the 4-terminal method. Further, the connection resistance was determined according to the following criteria.

[Criteria for connection resistance]
○○: Connection resistance is 2.0Ω or less ○: Connection resistance exceeds 2.0Ω, 3.0Ω or less △: Connection resistance exceeds 3.0Ω, 5.0Ω or less ×: Connection resistance exceeds 5.0Ω

(7) Impact resistance The impact resistance was evaluated by dropping the connection structure obtained in the above (6) connection resistance evaluation from a position of 70 cm in height and confirming conduction. The case where the rate of increase in resistance value from the initial resistance value was 50% or less was determined as “good”, and the case where the rate of increase in resistance value from the initial resistance value exceeded 50% was determined as “bad”.

(8) Presence or absence of formation of indentation Using a differential interference microscope, the electrodes provided on the glass substrate were observed from the glass substrate side of the connection structure obtained in the above (6) connection resistance evaluation, and conductive particles The presence or absence of the formation of the impression of the electrode in contact with was determined according to the following criteria. In addition, the presence or absence of the formation of the impression of the electrode was observed with a differential interference microscope so that the electrode area was 0.02 mm ^2, and the number of impressions per electrode of 0.02 mm ² was calculated. Arbitrary ten places were observed with the differential interference microscope, and the average value of the number of impressions per electrode 0.02 mm ² was calculated.

[Criteria for the presence or absence of indentation]
○: 25 or more indentations per electrode 0.02 mm ² ○: 20 or more indentations per electrode 0.02 mm ² , less than 25 Δ: 5 or more indentations per electrode 0.02 mm ² , 20 Less than x: Less than 5 impressions per electrode 0.02 mm ²

  The results are shown in Tables 1 and 2 below.

  In addition, the electroconductive particle of Examples 21-40 and Comparative Examples 4-6 was produced separately from the electroconductive particle of Examples 1-20 and Comparative Examples 1-3.

(Example 21)
Divinylbenzene copolymer resin particles having a particle size of 3.0 μm (“Micropearl SP-203” manufactured by Sekisui Chemical Co., Ltd.) were prepared.

  After dispersing 10 parts by weight of the resin particles in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, the resin particles were taken out by filtering the solution. Next, the resin particles were added to 100 parts by weight of a 1% by weight dimethylamine borane solution to activate the surface of the resin particles. The resin particles whose surface was activated were sufficiently washed with water, and then added to 500 parts by weight of distilled water and dispersed to obtain a suspension.

  Further, a nickel plating solution (pH 8.5) containing 0.23 mol / L of nickel sulfate, 0.92 mol / L of dimethylamine borane, 0.5 mol / L of sodium citrate and 0.01 mol / L of sodium tungstate was prepared.

  While stirring the obtained suspension at 60 ° C., the nickel plating solution was gradually added dropwise to the suspension to perform electroless nickel plating. Thereafter, by filtering the suspension, the particles are taken out, washed with water, and dried to obtain conductive particles having a nickel-boron-tungsten conductive layer (thickness 0.1 μm) disposed on the surface of the resin particles. It was.

(Example 22)
Conductive particles in which a nickel-boron-tungsten conductive layer (thickness 0.1 μm) is arranged on the surface of the resin particles are the same as in Example 21 except that the sodium tungstate concentration is changed to 0.12 mol / L. Obtained.

(Example 23)
Conductive particles in which a nickel-boron-tungsten conductive layer (thickness: 0.1 μm) is arranged on the surface of the resin particles are the same as in Example 21 except that the sodium tungstate concentration is changed to 0.23 mol / L. Obtained.

(Example 24)
Conductive particles in which a nickel-boron-tungsten conductive layer (thickness: 0.1 μm) is disposed on the surface of the resin particles are the same as in Example 21 except that the sodium tungstate concentration is changed to 0.35 mol / L. Obtained.

(Example 25)
Nickel-boron-tungsten was formed on the surface of the resin particles in the same manner as in Example 21 except that the dimethylamine borane concentration was changed to 2.76 mol / L and the sodium tungstate concentration was changed to 0.35 mol / L. Conductive particles having a conductive layer (thickness 0.1 μm) were obtained.

(Example 26)
(1) Palladium adhesion process The divinylbenzene resin particle ("Micropearl SP-205" by Sekisui Chemical Co., Ltd.) whose particle diameter is 5.0 micrometers was prepared. The resin particles were etched and washed with water. Next, resin particles were added to 100 mL of a palladium-catalyzed solution containing 8% by weight of a palladium catalyst and stirred. Then, it filtered and wash | cleaned. Resin particles were added to 0.5 wt% dimethylamine borane solution at pH 6 to obtain resin particles to which palladium was attached.

(2) Core substance adhesion step The resin particles to which palladium was adhered were stirred and dispersed in 300 mL of ion exchange water for 3 minutes to obtain a dispersion. Next, 1 g of metallic nickel particle slurry (average particle diameter 100 nm) was added to the dispersion over 3 minutes to obtain resin particles to which the core substance was adhered.

(3) Electroless nickel plating step In the same manner as in Example 21, conductive particles in which a nickel-boron-tungsten conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles were obtained.

(Example 27)
Conductive particles in which a nickel-boron-tungsten conductive layer (thickness: 0.1 μm) is arranged on the surface of the resin particles are the same as in Example 26 except that the sodium tungstate concentration is changed to 0.35 mol / L. Obtained.

(Example 28)
(1) Production of insulating particles A 1000 mL separable flask equipped with a four-neck separable cover, a stirring blade, a three-way cock, a condenser tube and a temperature probe was charged with 100 mmol methyl methacrylate and N, N, N-trimethyl. Ion-exchanged water containing a monomer composition containing 1 mmol of -N-2-methacryloyloxyethylammonium chloride and 1 mmol of 2,2'-azobis (2-amidinopropane) dihydrochloride so that the solid content is 5% by weight. Then, the mixture was stirred at 200 rpm and polymerized at 70 ° C. for 24 hours under a nitrogen atmosphere. After completion of the reaction, it was freeze-dried to obtain insulating particles having an ammonium group on the surface, an average particle size of 220 nm, and a CV value of 10%.

  The insulating particles were dispersed in ion exchange water under ultrasonic irradiation to obtain a 10 wt% aqueous dispersion of insulating particles.

  10 g of the conductive particles obtained in Example 26 were dispersed in 500 mL of ion exchange water, 4 g of an aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 6 hours. After filtration through a 3 μm mesh filter, the particles were further washed with methanol and dried to obtain conductive particles having insulating particles attached thereto.

  When observed with a scanning electron microscope (SEM), only one coating layer of insulating particles was formed on the surface of the conductive particles. The coverage of the insulating particles with respect to the area of 2.5 μm from the center of the conductive particles by image analysis (that is, the projected area of the particle diameter of the insulating particles) was calculated to be 30%.

(Example 29)
Conductive particles in which a nickel-boron-tungsten conductive layer (thickness 0.1 μm) is arranged on the surface of the resin particles are the same as in Example 21 except that the sodium tungstate concentration is changed to 0.46 mol / L. Obtained.

(Example 30)
Nickel-boron-tungsten was formed on the surface of the resin particles in the same manner as in Example 21 except that the dimethylamine borane concentration was changed to 4.60 mol / L and the sodium tungstate concentration was changed to 0.23 mol / L. Conductive particles having a conductive layer (thickness 0.1 μm) were obtained.

(Comparative Example 4)
In the same manner as in Example 21 except that 0.92 mol / L of dimethylamine borane in the nickel plating solution was changed to 0.5 mol / L of sodium hypophosphite, nickel, tungsten and phosphorus were added to the surface of the resin particles. The electroconductive particle by which the electroconductive layer (thickness 0.1 micrometer) containing was arrange | positioned was obtained. The phosphorus content in the entire conductive layer of 100% by weight was 8.7% by weight.

(Comparative Example 5)
A conductive layer (thickness 0.1 μm) containing nickel and boron was disposed on the surface of the resin particles in the same manner as in Example 21 except that 0.01 mol / L of sodium tungstate in the nickel plating solution was not used. Conductive particles were obtained.

(Example 31)
Divinylbenzene copolymer resin particles having a particle size of 3.0 μm (“Micropearl SP-203” manufactured by Sekisui Chemical Co., Ltd.) were prepared.

  After dispersing 10 parts by weight of the resin particles in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, the resin particles were taken out by filtering the solution. Next, the resin particles were added to 100 parts by weight of a 1% by weight dimethylamine borane solution to activate the surface of the resin particles. The resin particles whose surface was activated were sufficiently washed with water, and then added to 500 parts by weight of distilled water and dispersed to obtain a suspension.

  Further, a nickel plating solution (pH 8.5) containing 0.23 mol / L of nickel sulfate, 0.92 mol / L of dimethylamine borane, 0.5 mol / L of sodium citrate and 0.01 mol / L of sodium molybdate was prepared.

  While stirring the obtained suspension at 60 ° C., the nickel plating solution was gradually added dropwise to the suspension to perform electroless nickel plating. Thereafter, by filtering the suspension, the particles are taken out, washed with water, and dried to obtain conductive particles having a nickel-boron-molybdenum conductive layer (thickness 0.1 μm) disposed on the surface of the resin particles. It was.

(Example 32)
Conductive particles in which a nickel-boron-molybdenum conductive layer (thickness: 0.1 μm) is arranged on the surface of the resin particles are the same as in Example 31 except that the sodium molybdate concentration is changed to 0.12 mol / L. Obtained.

(Example 33)
Conductive particles in which a nickel-boron-molybdenum conductive layer (thickness: 0.1 μm) is arranged on the surface of the resin particles are the same as in Example 31 except that the sodium molybdate concentration is changed to 0.23 mol / L. Obtained.

(Example 34)
Conductive particles in which a nickel-boron-molybdenum conductive layer (thickness 0.1 μm) is arranged on the surface of the resin particles are the same as in Example 31 except that the sodium molybdate concentration is changed to 0.35 mol / L. Obtained.

(Example 35)
Nickel-boron-molybdenum was formed on the surface of the resin particles in the same manner as in Example 31 except that the dimethylamine borane concentration was changed to 2.76 mol / L and the sodium molybdate concentration was changed to 0.35 mol / L. Conductive particles having a conductive layer (thickness 0.1 μm) were obtained.

(Example 36)
(1) Palladium adhesion process The divinylbenzene resin particle ("Micropearl SP-205" by Sekisui Chemical Co., Ltd.) whose particle diameter is 5.0 micrometers was prepared. The resin particles were etched and washed with water. Next, resin particles were added to 100 mL of a palladium-catalyzed solution containing 8% by weight of a palladium catalyst and stirred. Then, it filtered and wash | cleaned. Resin particles were added to 0.5 wt% dimethylamine borane solution at pH 6 to obtain resin particles to which palladium was attached.

(2) Core substance adhesion step The resin particles to which palladium was adhered were stirred and dispersed in 300 mL of ion exchange water for 3 minutes to obtain a dispersion. Next, 1 g of metallic nickel particle slurry (average particle diameter 100 nm) was added to the dispersion over 3 minutes to obtain resin particles to which the core substance was adhered.

(3) Electroless nickel plating step In the same manner as in Example 31, conductive particles were obtained in which a nickel-boron-molybdenum conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles.

(Example 37)
Conductive particles in which a nickel-boron-molybdenum conductive layer (thickness: 0.1 μm) is arranged on the surface of the resin particles are the same as in Example 36 except that the sodium molybdate concentration is changed to 0.35 mol / L. Obtained.

(Example 38)
(1) Production of insulating particles A 1000 mL separable flask equipped with a four-neck separable cover, a stirring blade, a three-way cock, a condenser tube and a temperature probe was charged with 100 mmol methyl methacrylate and N, N, N-trimethyl. Ion-exchanged water containing a monomer composition containing 1 mmol of -N-2-methacryloyloxyethylammonium chloride and 1 mmol of 2,2'-azobis (2-amidinopropane) dihydrochloride so that the solid content is 5% by weight. Then, the mixture was stirred at 200 rpm and polymerized at 70 ° C. for 24 hours under a nitrogen atmosphere. After completion of the reaction, it was freeze-dried to obtain insulating particles having an ammonium group on the surface, an average particle size of 220 nm, and a CV value of 10%.

  The insulating particles were dispersed in ion exchange water under ultrasonic irradiation to obtain a 10 wt% aqueous dispersion of insulating particles.

  10 g of the conductive particles obtained in Example 36 were dispersed in 500 mL of ion exchange water, 4 g of an aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 6 hours. After filtration through a 3 μm mesh filter, the particles were further washed with methanol and dried to obtain conductive particles having insulating particles attached thereto.

  When observed with a scanning electron microscope (SEM), only one coating layer of insulating particles was formed on the surface of the conductive particles. The coverage of the insulating particles with respect to the area of 2.5 μm from the center of the conductive particles by image analysis (that is, the projected area of the particle diameter of the insulating particles) was calculated to be 30%.

(Example 39)
Conductive particles in which a nickel-boron-molybdenum conductive layer (thickness 0.1 μm) is arranged on the surface of the resin particles are the same as in Example 31 except that the sodium molybdate concentration is changed to 0.46 mol / L. Obtained.

(Example 40)
Nickel-boron-molybdenum was formed on the surface of the resin particles in the same manner as in Example 31 except that the dimethylamine borane concentration was changed to 4.60 mol / L and the sodium molybdate concentration was changed to 0.23 mol / L. Conductive particles having a conductive layer (thickness 0.1 μm) were obtained.

(Comparative Example 6)
In the same manner as in Example 31 except that 0.92 mol / L of dimethylamine borane in the nickel plating solution was changed to 0.5 mol / L of sodium hypophosphite, nickel, molybdenum and phosphorus were added to the surface of the resin particles. The electroconductive particle by which the electroconductive layer (thickness 0.1 micrometer) containing was arrange | positioned was obtained. The phosphorus content in the entire conductive layer of 100% by weight was 9.5% by weight.

(Evaluation of Examples 21 to 40 and Comparative Examples 4 to 6)
(1) Compressive elastic modulus of conductive particles (10% K value)
The compression modulus (10% K value) of the obtained conductive particles was measured using a micro compression tester (“Fischer Scope H-100” manufactured by Fischer).

(2) Compression Recovery Rate of Conductive Particles The compression recovery rate when the obtained conductive particles were compressed by 30% was measured using a micro compression tester (“Fischer Scope H-100” manufactured by Fischer).

(3) Content of nickel, boron, phosphorus, tungsten and molybdenum in 100% by weight of the entire conductive layer Add 5 g of conductive particles to a mixture of 5 mL of 60% nitric acid and 10 mL of 37% hydrochloric acid to complete the conductive layer. To obtain a solution. Using the obtained solution, the contents of nickel, boron, phosphorus, tungsten and molybdenum were analyzed with an ICP-MS analyzer (manufactured by Hitachi, Ltd.). In addition, the electroconductive layer in the electroconductive particle of an Example did not contain phosphorus.

(4) Plating state The plating state of 50 conductive particles obtained was observed with a scanning electron microscope. The presence or absence of plating unevenness such as plating cracking or plating peeling was observed. The case where the number of conductive particles in which plating unevenness was confirmed was 4 or less was judged as “good”, and the case where the number of conductive particles in which plating unevenness was confirmed was 5 or more was judged as “bad”.

(5) Aggregation state 10 parts by weight of bisphenol A type epoxy resin (“Epicoat 1009” manufactured by Mitsubishi Chemical Corporation), 40 parts by weight of acrylic rubber (weight average molecular weight of about 800,000), 200 parts by weight of methyl ethyl ketone, and microcapsule type curing 50 parts by weight of the agent (“HX3941HP” manufactured by Asahi Kasei Chemicals Co., Ltd.) and 2 parts by weight of the silane coupling agent (“SH6040” manufactured by Toray Dow Corning Silicone Co., Ltd.) are mixed to give a conductive particle content of 3% by weight. Thus, an anisotropic conductive material was obtained.

  The obtained anisotropic conductive material was stored at 25 ° C. for 72 hours. After storage, it was evaluated whether or not the conductive particles aggregated in the anisotropic conductive material were settled. The case where the aggregated conductive particles were not settled was judged as “good”, and the case where the aggregated conductive particles were settled was judged as “bad”.

(6) Initial connection resistance Fabrication of connection structure:
10 parts by weight of bisphenol A type epoxy resin (“Epicoat 1009” manufactured by Mitsubishi Chemical Corporation), 40 parts by weight of acrylic rubber (weight average molecular weight of about 800,000), 200 parts by weight of methyl ethyl ketone, and a microcapsule type curing agent (Asahi Kasei Chemicals) "HX3941HP" manufactured by HX3941) and 2 parts by weight of a silane coupling agent ("SH6040" manufactured by Toray Dow Corning Silicone Co., Ltd.) are mixed, and the conductive particles are added so that the content is 3% by weight. A resin composition was obtained by dispersing.

  The obtained resin composition was applied to a 50 μm-thick PET (polyethylene terephthalate) film whose one surface was released from the mold, and dried with hot air at 70 ° C. for 5 minutes to produce an anisotropic conductive film. The thickness of the obtained anisotropic conductive film was 12 μm.

  The obtained anisotropic conductive film was cut into a size of 5 mm × 5 mm. The cut anisotropic conductive film is formed of a glass substrate (width 3 cm, length 3 cm) having an aluminum electrode (height 0.2 μm, L / S = 20 μm / 20 μm) having a lead wire for resistance measurement on one side. Affixed almost at the center on the aluminum electrode side. Next, a two-layer flexible printed board (width 2 cm, length 1 cm) having the same aluminum electrode was bonded after being aligned so that the electrodes overlap each other. The laminated body of the glass substrate and the two-layer flexible printed circuit board was thermocompression bonded under pressure bonding conditions of 10 N, 180 ° C., and 20 seconds to obtain a connection structure. A two-layer flexible printed board in which an aluminum electrode is directly formed on a polyimide film was used.

Connection resistance measurement:
The connection resistance between the opposing electrodes of the obtained connection structure was measured by the 4-terminal method. The initial connection resistance was determined according to the following criteria.

[Criteria for connection resistance]
○○: Connection resistance is 2.0Ω or less ○: Connection resistance exceeds 2.0Ω, 3.0Ω or less △: Connection resistance exceeds 3.0Ω, 4.0Ω or less Δ △: Connection resistance is 4.0Ω Exceeding 5.0Ω or less ×: Connection resistance exceeds 5.0Ω

(7) Connection resistance after high-temperature and high-humidity test The connection structure obtained by producing the connection structure (6) was allowed to stand for 100 hours under the conditions of 85 ° C and 85% humidity. The connection resistance between the electrodes of the connection structure after being allowed to stand was measured by the four-terminal method, and the obtained measurement value was used as the connection resistance after the high temperature and high humidity test. Moreover, the connection resistance after a high temperature, high humidity test was determined according to the following criteria.

[Criteria for connection resistance]
○○: Connection resistance is 2.0Ω or less ○: Connection resistance exceeds 2.0Ω, 3.0Ω or less △: Connection resistance exceeds 3.0Ω, 4.0Ω or less Δ △: Connection resistance is 4.0Ω Exceeding 5.0Ω or less ×: Connection resistance exceeds 5.0Ω

(8) Impact resistance The connection structure obtained by the preparation of the connection structure (6) was dropped from a position of 70 cm in height, and the impact resistance was evaluated by confirming conduction. The case where the rate of increase in resistance value from the initial resistance value was 50% or less was determined as “good”, and the case where the rate of increase in resistance value from the initial resistance value exceeded 50% was determined as “bad”.

(9) Presence or absence of formation of indentation Using a differential interference microscope, the electrode provided on the glass substrate is observed from the glass substrate side of the connection structure obtained in (6) Preparation of the connection structure, and the conductivity is obtained. The presence or absence of indentation of the electrode in contact with the particles was determined according to the following criteria. In addition, the presence or absence of the formation of the impression of the electrode was observed with a differential interference microscope so that the electrode area was 0.02 mm ^2, and the number of impressions per electrode of 0.02 mm ² was calculated. Arbitrary ten places were observed with the differential interference microscope, and the average value of the number of impressions per electrode 0.02 mm ² was calculated.

[Criteria for the presence or absence of indentation]
○: 25 or more indentations per electrode 0.02 mm ² ○: 20 or more indentations per electrode 0.02 mm ² , less than 25 Δ: 5 or more indentations per electrode 0.02 mm ² , 20 Less than ×: One or more indentations per electrode 0.02 mm ² Less than 5, xx: No indentations per electrode 0.02 mm ²

  The results are shown in Tables 3 and 4 below.

DESCRIPTION OF SYMBOLS 1 ... Conductive particle 1a ... Protrusion 2 ... Base material particle 3 ... Conductive layer 3a ... Protrusion 4 ... Core substance 5 ... Insulating material 11 ... Conductive particle 11a ... Protrusion 12 ... Second conductive layer 13 ... Conductive layer 13a ... Protrusion DESCRIPTION OF SYMBOLS 21 ... Conductive particle 22 ... Conductive layer 22a ... Crack 51 ... Connection structure 52 ... 1st connection object member 52a ... Upper surface 52b ... Electrode 53 ... 2nd connection object member 53a ... Lower surface 53b ... Electrode 54 ... Connection part 71 ... Pad 72 ... Compression member 72a ... Smooth end face

Claims (14)

Substrate particles,
Are arranged on a surface of the base particle, and possess nickel, and boron, and a conductive layer comprising at least one metal component of the tungsten and molybdenum,
No other conductive layer is disposed on the outer surface of the conductive layer that is disposed on the surface of the base particle and includes nickel, boron, and the metal component,
The content of the metal component of the total of 100 wt% of the conductive layer disposed on the surface of the base particle is 0.01 wt% or more, Ru der 40 wt% or less, the conductive particles. 2. The conductive particle according to claim 1, wherein a content of the boron in 100% by weight of the conductive layer disposed on the surface of the base particle is 0.05% by weight or more and 4% by weight or less. . The content of the metal component in 100% by weight of the entire conductive layer disposed on the surface of the base particle is 0.1% by weight or more and 30% by weight or less. Conductive particles. 3. The conductive material according to claim 1, wherein a content of the metal component in a total of 100% by weight of the conductive layer disposed on the surface of the base particle is more than 5% by weight and 30% by weight or less. Sex particles.   The electroconductive particle of any one of Claims 1-4 in which the said metal component contains tungsten. 10% compressive deformation by compression modulus of elasticity of when the 5000N / mm ² or more and 15000 N / mm ² or less, the conductive particles according to any one of claims 1 to 5.   The electroconductive particle of any one of Claims 1-6 whose compression recovery rate is 5% or more and 70% or less.   The electroconductive particle of any one of Claims 1-7 in which the said metal component contains molybdenum. The conductive layer disposed on the surface of the substrate particles includes nickel and molybdenum;
Of 100% by weight of the entire conductive layer disposed on the surface of the substrate particle , the nickel content is 70% by weight or more and 99.9% by weight or less, and the molybdenum content is 0.1% by weight. Above, the electroconductive particle of any one of Claims 1-8 which is 30 weight% or less. The compression elastic modulus when compressed at 5% is 7000 N / mm ² or more, and exceeds 10% of the particle diameter of the conductive particles before compression in the compression direction, and the conductive particles are compressed at 25% or less. The conductive particle according to any one of claims 1 to 9, wherein the conductive layer disposed on the surface of the base particle is sometimes cracked. The electroconductive particle of any one of Claims 1-10 whose thickness of the said electroconductive layer arrange | positioned on the surface of the said base particle is 0.05 micrometer or more and 0.5 micrometer or less. The electroconductive particle of any one of Claims 1-11 in which the said conductive layer arrange | positioned on the surface of the said base particle has a processus | protrusion on an outer surface.   The electroconductive material containing the electroconductive particle of any one of Claims 1-12, and binder resin. A first connection target member, a second connection target member, and a connection portion connecting the first and second connection target members;
A connection structure in which the connection portion is formed of the conductive particles according to any one of claims 1 to 12, or is formed of a conductive material including the conductive particles and a binder resin.

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