TWI511166B - Conductive particles, conductive materials and connecting structures - Google Patents

Description

Conductive particles, conductive materials, and connection structures

The present invention relates to an electroconductive particle in which a conductive layer is disposed on a surface of a substrate particle, and more specifically, for example, an electroconductive particle which can be used for electrical connection between electrodes. Moreover, the present invention relates to a conductive material and a connection structure using the above conductive particles.

Anisotropic conductive materials such as an anisotropic conductive paste and an anisotropic conductive film are widely known. The anisotropic conductive material is obtained by dispersing conductive particles in a binder resin.

The anisotropic conductive material is used in the connection between an IC (integrated circuit) wafer and a flexible printed circuit board, and an IC chip and a circuit substrate having an ITO (Indium Tin Oxide) electrode. Connection, etc. For example, an anisotropic conductive material may be disposed between the electrodes of the IC wafer and the electrodes of the circuit board, and then the electrodes may be electrically connected by heating and pressurization.

As an example of the above-mentioned conductive particles, in the following Patent Document 1, a surface of spherical substrate particles having an average particle diameter of 1 to 20 μm is disclosed, and a nickel conductive layer or a nickel alloy is formed by electroless plating. Conductive particles formed by a conductive layer. The conductive particles have minute protrusions of 0.05 to 4 μm in the outermost layer of the conductive layer. The conductive layer is substantially continuously connected to the protrusion.

Further, Patent Document 2 listed below discloses conductive particles including a substrate particle and a conductive layer formed on the surface of the substrate particle. To form the substrate particles, a mixture of divinylbenzene-ethylvinylbenzene is used as part of the monomer. The conductive particles have a compression elastic modulus of at least 2.5 × 10 ⁹ N/m ² when the particle diameter is 10% displaced, a compression deformation recovery ratio of 30% or more, and a fracture strain of 30% or more. Patent Document 2 describes that when the electrodes of the substrate are electrically connected to each other by using the conductive particles, the connection resistance is lowered and the connection reliability is improved.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2000-243132

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2003-313304

When the electrodes are connected by the conductive particles described in Patent Document 1, the connection resistance between the electrodes may be improved. In the case where the electrodes are connected by an anisotropic conductive material containing the conductive particles described in Patent Document 1, the resin component between the electrode and the conductive particles may not be sufficiently removed. Therefore, there is a case where the connection resistance between the electrodes connected by the conductive particles contained in the anisotropic conductive material is improved.

Further, the conductive particles of the examples of Patent Document 1 form a conductive layer containing nickel and phosphorus. An oxide film is formed on the surface of the electrode to which the conductive particles are connected and the conductive layer of the conductive particles. When the electrodes are connected by using conductive particles containing a conductive layer containing nickel and phosphorus, since the conductive layer containing nickel and phosphorus is relatively soft, the oxide film on the surface of the electrode and the conductive particles may not be sufficiently removed, and thus the resistance may be connected. improve.

In addition, when the thickness of the conductive layer containing nickel and phosphorus described in Patent Document 1 is increased to reduce the connection resistance, the conductive particles may damage the member to be bonded or the substrate. If the connection member or the electrode is damaged, it is easy to increase the connection resistance. Further, when the electrode or the member to be connected is damaged, the conduction reliability between the electrodes is lowered.

Further, as the prior conductive particles described in Patent Document 1, a plurality of conductive particles are aggregated. When a plurality of agglomerated conductive particles are used to connect the electrodes, a short circuit may occur between the electrodes.

Further, in the conductive particles described in Patent Document 2, the oxide film may not be sufficiently removed, or the damage of the connection member or the substrate may not be suppressed. Therefore, when the conductive particles described in Patent Document 2 are used, it is also difficult to sufficiently reduce the connection resistance between the electrodes.

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

A limited object of the present invention is to provide an oxide film which can effectively remove the surface of the electrode and the conductive particles when the electrodes are connected, and can reduce the connection resistance between the electrodes, and use the conductive material. Conductive material and connecting structure of the particles.

A limited object of the present invention is to provide a conductive material and a connection structure which can effectively remove the resin component between the electrode and the conductive particles when the electrodes are connected, and can reduce the connection resistance between the electrodes.

According to a broader aspect of the present invention, there is provided a conductive particle comprising a substrate particle and a conductive layer disposed on a surface of the substrate particle and containing nickel, boron, and tungsten and molybdenum At least one metal component in the middle.

In a specific aspect of the conductive particles of the present invention, the content of the boron in 100% by weight of the entire conductive layer is 0.05% by weight or more and 4% by weight or less.

In a specific aspect of the conductive particles of the present invention, the content of the metal component in 100% by weight of the total of the conductive layer is 0.1% by weight or more and 30% by weight or less.

In a specific aspect of the conductive particles of the present invention, the content of the metal component in the total 100% by weight of the conductive layer is more than 5% by weight and not more than 30% by weight.

In a specific aspect of the conductive particles of the present invention, the metal component contains tungsten.

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

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

In a specific aspect of the conductive particles of the present invention, the metal component contains molybdenum.

In a specific aspect of the conductive particles of the present invention, the conductive layer contains nickel and molybdenum, and the content of nickel in the whole 100% by weight of the conductive layer is 70% by weight or more and 99.9% by weight or less, and the content of molybdenum is 0.1% by weight or more and 30% by weight or less.

In a specific aspect of the conductive particles of the present invention, the compression elastic modulus at 5% compression is 7000 N/mm ² or more, and the particle diameter of the conductive particles before compression is more than 10% and 25 in the compression direction. When the conductive particles are compressed below %, the conductive layer is cracked.

In a specific aspect of the conductive particles of the present invention, the conductive layer has a thickness of 0.05 μm or more and 0.5 μm or less.

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

The conductive material of the present invention contains the above-mentioned conductive particles 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 that connects the first and second connection target members, and the connection portion is formed by the conductive particles or contains The conductive particles and the conductive material of the binder resin are formed.

In the conductive particles of the present invention, a conductive layer containing at least one of nickel, boron, and at least one of tungsten and molybdenum is disposed on the surface of the substrate particles, so that aggregation of a plurality of conductive particles can be suppressed. Further, when the electrodes are connected by using the conductive particles of the present invention, the connection resistance can be lowered.

Hereinafter, the present invention will be described in detail.

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

The conductive particles of the present invention can suppress aggregation of a plurality of conductive particles by adopting the above configuration. Since a plurality of conductive particles can be suppressed from aggregating, it is possible to effectively prevent a short circuit between the electrodes. Further, in the case where the conductive particles of the present invention have the above-described configuration, when the electrodes are connected using the conductive particles of the present invention, the connection resistance can be lowered.

When the electrodes are connected by the conductive particles containing the conductive layer containing nickel, the connection resistance between the electrodes is lowered. When the content of nickel in the entire 100% by weight of the conductive layer X of the conductive particles of the present invention is 50% by weight or more, the connection resistance between the electrodes is remarkably lowered. Therefore, in 100% by weight of the entire conductive layer X, the content of nickel is preferably 50% by weight or more.

Further, in the conductive particles containing the nickel conductive layer containing no boron, the nickel-free conductive layer containing no boron is excessively soft, and when the electrodes are connected to each other, the oxide film on the surface of the electrode and the conductive particles cannot be sufficiently removed. The connection resistance is increased. For example, the conductive particles including the conductive layer containing nickel and phosphorus cannot sufficiently remove the oxide film on the surfaces of the electrode and the conductive particles, and the connection resistance is easily improved. In particular, when the content of phosphorus in 100% by weight of the entire conductive layer is 10.5% by weight or more, the connection resistance is easily improved, and when it is 1% by weight or more, the connection resistance is more easily improved.

On the other hand, if the thickness of the conductive layer containing nickel and phosphorus is increased in order to lower the connection resistance, the conductive particles may damage the member or substrate to be bonded. The situation.

On the other hand, the hardness of the above-mentioned conductive layer X containing nickel and boron is relatively high, so that the connection resistance between the electrodes can be reduced. When the electrodes are connected, the oxide film on the surfaces of the electrodes and the conductive particles can be eliminated, and the connection resistance can be lowered.

Further, in the conductive particles of the present invention, the conductive layer X contains not only boron but also at least one metal component M of tungsten and molybdenum, so that the conductive layer X containing boron and the metal component M can be remarkably hardened. . Therefore, the oxide film on the surface of the electrode and the conductive particles can be sufficiently removed, and the connection resistance can be remarkably lowered. In particular, 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 the conductive particles can be more effectively removed, and the connection resistance can be further reduced.

Further, when the conductive layer X contains the metal component M, the conductive layer X is remarkably hardened, and as a result, even if the connection structure is connected to the electrodes by the conductive particles, the conduction failure is less likely to occur. . That is, the impact resistance of the connection structure can also be improved.

Further, the former conductive particles have a high magnetic field on the surface of the conductive layer, and the surface of the conductive layer containing nickel and boron has high magnetic properties, so that the electrodes are electrically connected to each other due to magnetic properties. The influence of the agglomerated conductive particles tends to be easily connected between adjacent electrodes in the lateral direction. In the conductive particles of the present invention, since the conductive layer X contains the metal component M, the magnetic properties of the surface of the conductive layer X are remarkably lowered. Therefore, aggregation of a plurality of conductive particles can be suppressed. Therefore, the electrode In the case of electrically connecting, it is possible to suppress the connection between the electrodes adjacent in the lateral direction due to the aggregated conductive particles. That is, the short circuit between adjacent electrodes can be further prevented.

It is preferable that the content of nickel is 70% by weight or more and 99.9% by weight or less based on 100% by weight of the entire conductive layer X, and the content of the metal component M is 0.1% by weight or more and 30% by weight or less. Further, it is preferable that the conductive layer X does not contain phosphorus, or that 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.

It is preferable that the content of nickel is 70% by weight or more and 99.9% by weight or less in the entire 100% by weight of the conductive layer X, and the content of the metal component M is 0.1% by weight or more and 30% by weight or less, and the conductive layer X is Phosphorus is not contained, or the above-mentioned 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 such a preferred configuration are used for the connection between the electrodes, the oxide film on the surface of the electrode and the conductive particles can be effectively removed. Therefore, the connection resistance between the electrodes of the obtained connection structure can be further reduced. In addition, since the content of nickel in the conductive particles having the preferred configuration is 70% by weight or more, the connection resistance between the electrodes is remarkably lowered.

In addition, when the content of the metal component M in the whole 100% by weight of the conductive layer X is 0.1% by weight or more and 30% by weight or less, the conductive layer X is remarkable as compared with the conductive layer not containing the metal component M. Harden. Therefore, the oxide film on the surface of the electrode and the conductive particles can be effectively removed, and as a result, the connection resistance between the electrodes is further lowered. Moreover, in the case where the conductive particles and the binder resin are blended, the electrodes are connected by using a conductive material. In this case, the resin component between the electrode and the conductive particles can be effectively removed, whereby the connection resistance between the electrodes can be further reduced.

The compression elastic modulus (10% K value) when the conductive particles of the present invention are subjected to 10% compression deformation is preferably 5,000 N/mm ² or more, more preferably 7,000 N/mm ² or more, and preferably 15,000 N. /mm ² or less, more preferably 10000 N/mm ² or less. When the compression elastic modulus (10% K value) is at least the above lower limit, the oxide film on the surface of the electrode and the conductive particles can be more effectively removed, and the electrode and the conductive particle can be more effectively removed. As a result of the resin component, the connection resistance between the electrodes was further lowered.

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

The conductive particles were compressed using a micro-compression tester using a smooth indenter end face of a cylinder (diameter 50 μm, made of diamond) at a compression speed of 2.6 mN/s and a maximum test load of 10 gf. The load value (N) and the compression displacement (mm) at this time were measured. The above-described compression elastic modulus can be obtained by the following formula based on the obtained measured value. As the micro compression tester, for example, "Fischerscope H-100" manufactured by Fischer Co., Ltd. or the like can be used.

K value (N/mm ² ) = (3/2 ^1/2 ). F. S ^-3/2 . R ^-1/2

F: load value when the conductive particles generate 10% compression deformation (N)

S: Compressive displacement (mm) when the conductive particles are subjected to 10% compression deformation

R: radius of conductive particles (mm)

The compression recovery ratio of the conductive particles is preferably 5% or more, more preferably 20% or more, and is preferably 70% or less, more preferably 60% or less, still more preferably 50% or less. When the compression recovery ratio is not less than the above lower limit and not more than the above upper limit, oxygen on the surface of the electrode and the conductive particles can be more effectively excluded. Further, the film is removed, and the resin component between the electrode and the conductive particles can be more effectively removed, and as a result, the connection resistance between the electrodes is further lowered. Further, it is more difficult for the interface between the cured material and the connecting portion other than the conductive particles to be peeled off from the interface between the conductive particles and the member to be bonded. Further, the repulsive force of the conductive particles used for the connection between the electrodes can be suppressed, and as a result, the conductive material is less likely to be peeled off from the substrate or the like. Thereby, the connection resistance between the electrodes is further lowered.

The above compression recovery rate can be measured as follows.

Conductive particles are scattered on the sample stage. A load (inversion load value) was applied to the center of the conductive particles by using a micro compression tester for one of the conductive particles dispersed until the conductive particles were subjected to 30% compression deformation. Thereafter, the load is removed until the origin load value (0.40 mN). The load-compression displacement therebetween was measured, and the compression recovery ratio was obtained according to the following formula. Furthermore, the load speed was set to 0.33 mN/s. As the micro compression tester, for example, "Fischerscope H-100" manufactured by Fischer Co., Ltd. or the like can be used.

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

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

L2: Unloading displacement from the reversal load value to the origin load value when the load is released

Further, the compression elastic modulus and the compression recovery ratio may be the type of the substrate particles, the particle diameter of the substrate particles, the content of nickel in 100% by weight of the entire conductive layer X, and the conductive layer X. 100% by weight overall The content of the metal component M, the content of phosphorus in 100% by weight of the entire conductive layer X, the content of boron in the entire 100% by weight of the conductive layer X, the thickness of the conductive layer X, and the like are appropriately adjusted.

The conductive particles of the present invention preferably have a compression elastic modulus (5% K value) of 7,000 N/mm ² or more at 5% compression.

Further, in the conductive particles of the present invention, 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, the conductive layer is cracked. In other words, when the conductive particles of the present invention are compressed, when the conductive particles are compressed by more than 10% and 25% or less of the particle diameter of the conductive particles before the compression, the conductive particles are preferably formed. The layer produces cracks. That is, the compressive displacement of the conductive particles in which the conductive layer is cracked is preferably more than 10% and 25% or less. For example, when the conductive particles are largely compressed, the conductive layer partially generates cracks. The conductive particles having such properties are not only sufficiently high in hardness at the initial stage of compression, but also cracks when subjected to moderate compression. When the electrodes are connected to each other, cracks are generated in the conductive layer at the stage where the conductive particles are moderately compressed, so that electrode damage can be suppressed. As a result, the connection resistance between the electrodes of the obtained connection structure can be further reduced, and the conduction reliability between the electrodes can be further improved.

The conductive particles of the present invention preferably have a compressive elastic modulus (5% K value) of 7,000 N/mm ² or more when compressed at 5%, and when compressed in the case of the conductive particles of the present invention, when in the compression direction When the conductive particles are compressed by more than 10% and 25% or less of the particle diameter of the conductive particles before compression, the conductive layer is cracked. When the conductive particles having the preferred configuration are used for the connection between the electrodes, the connection resistance between the electrodes can be further reduced.

When the conductive elastic modulus (5% K value) of the conductive particles of the present invention at 5% compression is 7000 N/mm ² or more, the conductive particles in the initial stage of compression have sufficient hardness. Therefore, in the initial stage of compression of the conductive particles when the electrodes are connected, the oxide film on the surface of the electrode and the conductive particles can be effectively removed. As a result, the electrode is in effective contact with the conductive layer of the conductive particles, and the connection resistance between the electrodes can be further lowered.

On the other hand, in the case where the conductive elastic particles having a compression elastic modulus (5% K value) of 5% compression are not connected to 7000 N/mm ² , the electrodes are electrically connected, and compression is performed when 5% compression is used. When the conductive particles having a modulus of elasticity (5% K value) of 7000 N/mm ² or more have a tendency to electrically connect the electrodes, the exclusion property of the oxide film on the surface of the electrode and the conductive particles tends to be lowered. The tendency of the connection resistance between the electrodes to increase.

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

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

The conductive particles were compressed using a micro-compression tester using a smooth indenter end face of a cylinder (diameter 50 μm, made of diamond) at a compression speed of 2.6 mN/s and a maximum test load of 10 gf. The load value (N) and the compression displacement (mm) at this time were measured. From the measured values obtained, the above-described compression elastic modulus can be obtained by the following formula. As the micro compression tester, for example, "Fischerscope H-100" manufactured by Fischer Co., Ltd. or the like can be used.

K value (N/mm ² ) = (3/2 ^1/2 ). F. S ^-3/2 . R ^-1/2

F: load value when the conductive particles generate 5% compression deformation (N)

S: Compressive displacement (mm) when conductive particles produce 5% compression deformation

R: radius of conductive particles (mm)

The above compression elastic modulus (10% K value and 5% K value) can generally and quantitatively indicate the hardness of the conductive particles. By using the above-described compression elastic modulus, the hardness of the conductive particles can be quantitatively and uniquely expressed.

From the viewpoint of further reducing the connection resistance between the electrodes, the compression displacement of the conductive layer to generate cracks is more preferably 12% or more, and still more preferably 20% or less.

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

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

As shown in FIG. 1, the conductive particles 1 include a substrate particle 2, a conductive layer 3, a plurality of core materials 4, and a plurality of insulating materials 5.

The conductive layer 3 is disposed on the surface of the substrate particles 2. The conductive layer 3 contains nickel, boron, and the above-described metal component M. The conductive layer 3 is a nickel-boron-tungsten/molybdenum conductive layer. The conductive particles 1 are coated particles in which the surface of the substrate particles 2 is covered with the conductive layer 3.

The electroconductive particle 1 has 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 materials 4 are disposed on the surface of the substrate particles 2. A plurality of core materials 4 are buried in the conductive layer 3. The core material 4 is disposed inside the protrusions 1a and 3a. The conductive layer 3 is coated with a plurality of core materials 4. The protrusions 1a, 3a are formed by a plurality of core materials 4, and the outer surface of the conductive layer 3 is raised.

The conductive particles 1 include an insulating material 5 disposed on the outer surface of the conductive layer 3. At least a portion of the outer surface of the conductive layer 3 is covered with the insulating material 5. The insulating material 5 is formed of an insulating material and is an insulating particle. As such, the conductive particles of the present invention may further comprise an insulating material disposed on the outer surface of the conductive layer. However, the conductive particles of the present invention may not necessarily contain an insulating material.

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

The conductive particles 11 shown in FIG. 2 include a substrate particle 2, a second conductive layer 12 (other conductive layer), a conductive layer 13 (first conductive layer), a plurality of core materials 4, and a plurality of insulating materials 5.

Between the conductive particles 1 and the conductive particles 11, only the conductive layers are different. In other words, a conductive layer having a single-layer structure is formed in the conductive particles 1. On the other hand, the second conductive layer 12 and the conductive layer 13 having a two-layer structure are formed in the conductive particles 11.

The conductive layer 13 is disposed on the surface of the substrate particles 2. The second conductive layer 12 (other conductive layer) is disposed between the substrate particles 2 and the conductive layer 13. Therefore, the second conductive layer 12 is disposed on the surface of the substrate particle 2, and the conductive layer 13 is disposed on the surface of the second conductive layer 12. The conductive layer 13 contains 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.

Figure 3 is a cross section showing conductive particles according to a third embodiment of the present invention. Figure.

The conductive particles 21 shown in FIG. 3 include the substrate particles 2 and the conductive layer 22. The conductive layer 22 is disposed on the surface of the substrate particles 2. The conductive layer 22 contains nickel, boron, and the above-described metal component M.

The conductive particles 21 do not contain a core substance. The surface of the conductive particles 21 does not have protrusions. The conductive particles 21 are spherical. The surface of the conductive layer 22 has no protrusions. As described above, the conductive particles of the present invention may have no protrusions or may be spherical. Further, the conductive particles 21 do not contain an insulating material. However, the conductive particles 21 may also include an insulating material disposed on the surface of the conductive layer 22.

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

The 5% K value of the conductive particles 1, 11, and 21 is preferably 7,000 N/mm ² or more. Further, in the case of compressing the conductive particles 1, 11, and 21, it is preferable to make the conductive particles more than 10% and 25% or less of the particle diameter of the front conductive particles 1, 11, and 21 in the compression direction. When the compression displacement is generated by 1, 11, and 21, the conductive layers 3, 13, 22 are cracked. In other words, it is preferable that the conductive particles 1, 11, and 21 have particles of the conductive particles 1, 11, 21 in the compression direction when the particle diameters of the conductive particles 1, 11, 21 before compression are set to X in the compression direction. When the diameter is 0.75X or more and less than 0.90X, the conductive layers 3, 13, and 22 are cracked. For example, when the particle diameter of the front conductive particles 1, 11, 21 is 5 μm in the compression direction, it is preferable to compress the conductive particles 1, 11, 21 so that the conductive particles 1 and 11 in the compression direction are obtained. When the particle diameter of 21 becomes 3.75 μm or more and less than 4.5 μm, the conductive layers 3, 13, and 22 are cracked. Further, in the conductive particles 11, not only the conductive layer 13 may be cracked, but also the second conductive layer 12 may be cracked.

Further, the above "crack" means the first (first time) crack in the conductive layer. Therefore, in the conductive particles 1, 11, and 21 of the present embodiment, when the conductive particles 1, 11, and 21 including the non-cracking conductive layers 3, 13, and 22 are compressed, the conductive particles 1 are preferably used. When 11, 21 and 21 are less than 10% and 25% or less of the particle diameters of the pre-compressed conductive particles 1, 11, and 21 in the compression direction to cause a compression displacement, the conductive layers 3, 13, and 22 are cracked.

The measurement of the compression displacement in which the conductive layers 3, 13, 22 are cracked is specifically performed as follows. Further, in Fig. 5, conductive particles 21 are used.

As shown in FIG. 5, the conductive particles 21 are placed on the stage 71. Using a micro compression tester (Fischerscope H-100 manufactured by Fischer), a cylinder (diameter 50 μm, made of diamond) was used as the compression member 72 under the conditions of a compression speed of 0.33 mN/s and a maximum test load of 10 mN. The smooth end surface 72a of the compression member 72 is caused to fall 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 the conductive particles 1 and 11, the measurement can also be carried out in the same manner.

In addition, in the cross-sectional view shown in FIG. 5, the state in which the crack 22a is formed in the lower conductive layer 22 above the conductive particles 21 is shown, but in the conductive layer The position at which the crack is generated is not particularly limited.

When the conductive particles are compressed in the above manner, when the conductive particles are compressed by more than 10% of the particle diameter of the conductive particles before compression in the compression direction, the conductive layer is cracked and is less than 25%. When the displacement is compressed, the conductive layer generates cracks.

The compression load value and the compression displacement were measured while compressing the conductive particles, and the relationship between the compression load value and the compression displacement was as shown in Fig. 6, for example. In Fig. 6, the compression starts from the A0 point, and cracks are generated in the conductive layer of the A1 point. As the conductive layer is cracked, the compression displacement (particle diameter) of the conductive particles changes in the compression direction, and the compression displacement moves from the point A1 to the point A2. When compressing, the compressive load is applied to the conductive particles. If the conductive layer is cracked, the conductive particles can be compressed by a relatively small compressive load. Therefore, the compressive member that applies the compressive load to the conductive particles moves, and the conductive direction is conductive. The compressive displacement (particle size) of the particles changes.

Furthermore, in Fig. 6, the slope of the line from the point A0 to the 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 increases.

[Substrate particles]

Examples of the substrate particles include resin particles, inorganic particles other than metal particles, organic-inorganic mixed particles, and metal particles. The substrate particles are preferably other than metal particles, and are preferably resin particles or inorganic particles other than metal particles or organic-inorganic hybrid particles.

The substrate particles are preferably resin particles formed of a resin. Use the above When the conductive particles are connected between the electrodes, the conductive particles are placed between the electrodes, and then the conductive particles are compressed by pressure bonding. When the base material particles are resin particles, the conductive particles are likely to be deformed during the pressure bonding, and the contact area between the conductive particles and the electrode is increased. Therefore, the conduction reliability between the electrodes is improved.

Examples of the resin for forming the resin particles include a polyolefin resin, an acrylic resin, a phenol resin, a melamine resin, and a benzoquinone. Resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polyfluorene, polyphenylene ether, polyacetal, polyimide, polyamidoxime Amine, polyetheretherketone, polyether oxime, divinylbenzene polymer, and divinylbenzene copolymer. Examples of the divinylbenzene-based copolymer and the like include a divinylbenzene-styrene copolymer and a divinylbenzene-(meth)acrylate copolymer. The resin for forming the resin particles is preferably a polymer obtained by polymerizing one or two or more kinds of polymerizable monomers having a plurality of ethylenically unsaturated groups, because the substrate particles can be easily used. The hardness is controlled within a suitable range.

Examples of the inorganic material for forming the inorganic particles include cerium oxide, carbon black, and the like. Examples of the organic-inorganic hybrid particles include organic-inorganic mixed particles formed of a crosslinked alkoxyalkylene alkyl polymer and an acrylic resin.

In the case where the substrate particles are metal particles, examples of the metal for forming the metal particles include silver, copper, nickel, rhodium, gold, and titanium.

The particle diameter of the substrate particles is preferably 0.1 μm or more, more preferably 1 μm or more, further preferably 1.5 μm or more, and particularly preferably 2 μm or more, and preferably It is 1000 μm or less, more preferably 500 μm or less, further preferably 300 μm or less, further preferably 50 μm or less, particularly preferably 30 μm or less, and most preferably 5 μm or less. When the particle diameter of the substrate particles is at least the above lower limit, the contact area between the conductive particles and the electrode is increased. Therefore, the conduction reliability between the electrodes is further improved, and the connection resistance between the electrodes connected via the conductive particles is further lowered. Further, when the conductive layer is formed on the surface of the substrate particles by electroless plating, aggregation is less likely to occur, and aggregation of the conductive particles is less likely to occur. When the particle diameter is at most the above upper limit, the conductive particles are easily compressed sufficiently, and the connection resistance between the electrodes is further lowered, and the interval between the electrodes is further reduced. The particle diameter of the substrate particles is a diameter when the substrate particles are spherical, and indicates a maximum diameter when the substrate particles are not spherical.

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, the interval between the electrodes becomes small, and even if the thickness of the conductive layer is increased, a small amount of conductive particles can be obtained.

[conductive layer]

The conductive particles of the present invention comprise a conductive layer X which is disposed on the surface of the substrate particles and contains nickel, boron, and at least one metal component M of tungsten and molybdenum. The conductive layer X may be directly deposited on the surface of the substrate particles, or may be disposed on the surface of the substrate particles via another conductive layer or the like. Further, another conductive layer may be disposed on the surface of the conductive layer X. Preferably, no other conductive layer is disposed on the surface of the outer side of the conductive layer X. The outer surface of the conductive particles is preferably a conductive layer X containing nickel. By including When the conductive particles having the conductive layer X of nickel connect the electrodes, the connection resistance is further lowered.

The conductive layer X contains nickel, boron, and 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 contains nickel, boron and tungsten, preferably contains nickel, boron and molybdenum, preferably 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, 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 may be alloyed with boron, nickel may be alloyed with the metal component M, or boron may be alloyed with the metal component M. Further, in the conductive layer X, in addition to nickel, boron, and the metal component M, chromium may be used. (seaborgium).

Further, in the conductive particles including the nickel conductive layer not containing both tungsten and molybdenum, the nickel conductive layer not containing both tungsten and molybdenum is relatively easily reduced in hardness at the initial stage of compression. Therefore, when the electrodes are connected, the effect of eliminating the oxide film on the surface of the electrode and the conductive particles is small, and the effect of lowering the connection resistance tends to be small.

On the other hand, if a thickness of the nickel conductive layer which does not contain both tungsten and molybdenum is thickened in order to obtain a larger effect of lowering the connection resistance or to make it suitable for a large current, there is a conductive particle. It tends to cause damage to the connecting member or the substrate. As a result, the conduction reliability between the electrodes of the connection structure tends to decrease.

In contrast, the conductive layer X contains nickel, tungsten, and molybdenum. Since at least one metal component M is used, it is easy to make the said 5% K value into the said minimum. Further, when the conductive particles are compressed by more than 10% and 25% or less of the particle diameter of the pre-conducting conductive particles in the compression direction, the conductive layer X is moderately cracked. Since cracks are generated when subjected to moderate compression, electrode damage is more difficult to occur, and the connection resistance between the electrodes is further lowered.

Further, since the conductive layer X contains nickel and at least one metal component M of tungsten and molybdenum, the conductive layer X has an appropriate hardness. Therefore, when the conductive particles are compressed and the electrodes are connected to each other, they can be formed on the electrodes. Form a moderate indentation. Further, the indentation formed on the electrode is a concave portion of the electrode formed by pressing the electrode with the 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, the content of nickel in 100% by weight of the entire conductive layer X is preferably as large as possible. Therefore, the content of nickel in the entire 100% by weight of the conductive layer X is preferably 50% by weight or more, more preferably 60% by weight or more, still more preferably 70% by weight or more, and still more preferably 75% by weight or more. Further, it is more preferably 80% by weight or more, still more 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, or may be 97.5% by weight or more, or may be 98% by weight or more. When the content of the nickel is at least the above lower limit, the connection resistance between the electrodes is further lowered. Further, when the amount of the oxide film on the surface of the electrode or the conductive layer is small, the connection resistance between the electrodes tends to decrease as the content of the nickel is increased.

The upper limit of the content of nickel can be appropriately changed by the content of boron and the metal component M described above. 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 less than 99.45% by weight.

In the conductive particles containing the nickel-conducting layer containing no boron, the nickel-free conductive layer containing no boron is relatively soft in the initial stage of compression, and when the electrodes are connected to each other, the effect of removing the oxide film on the surface of the electrode and the conductive particles is obtained. It becomes smaller, and the effect of lowering the connection resistance becomes smaller. Further, the conductive layer may contain phosphorus and does not contain boron. The conductive particles containing the conductive layer containing nickel and phosphorus have a small effect of eliminating the oxide film on the surface of the electrode and the conductive particles, and the effect of lowering the connection resistance tends to be small.

On the other hand, if a larger effect of lowering the connection resistance is obtained, or the application is suitable for a large current, the thickness of the conductive layer not containing boron is thickened, or a conductive layer containing nickel and phosphorus is used. When the thickness is increased, the conductive particles tend to cause damage to the connection member or the substrate. As a result, the conduction reliability between the electrodes of the connection structure tends to decrease.

On the other hand, since the conductive layer X contains boron, the 5% K value is likely to be equal to or higher than the lower limit. Further, when the conductive particles are compressed by more than 10% and 25% or less of the particle diameter of the pre-conducting conductive particles in the compression direction, the conductive layer X is moderately cracked. Moreover, by making the conductive layer X contain nickel, boron, and the metal component M, it is easier to make the 5% K value equal to or higher than the lower limit. Further, when the conductive particles are compressed by more than 10% and 25% or less of the particle diameter of the pre-conducting conductive particles in the compression direction, the conductive layer X is more appropriately cracked. borrow Since the crack is generated when moderately compressed, the damage of the electrode is less likely to occur, and the connection resistance between the electrodes is further lowered.

Further, since the conductive layer X contains boron, the conductive layer X has an appropriate hardness, so that damage of the electrode is less likely to occur, and the connection resistance between the electrodes is further lowered. Further, since the conductive layer X contains boron, the conductive layer X has an appropriate hardness. Therefore, when the conductive particles are compressed and the electrodes are connected to each other, an appropriate indentation can be formed on the electrodes.

In particular, since the conductive layer X contains nickel, boron, and the above-described metal component M, a high compressive elastic modulus can be achieved. Therefore, in the initial stage of compression of the conductive particles when the electrodes are connected, the oxide film on the surface of the electrode and the conductive particles can be effectively removed, and the conductive particles are appropriately compressed at the time of connecting the electrodes. The conductive layer X generates cracks, so that damage of the electrodes can be suppressed. As a result, the connection resistance between the electrodes in the obtained connection structure can be lowered, and the conduction reliability between the electrodes can be improved.

The content of boron in 100% by weight of the entire conductive layer X is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, further preferably 0.1% by weight or more, and preferably 5% by weight or less, more preferably 4% by weight or less, further preferably 3% by weight or less, particularly preferably 2.5% by weight or less, and most preferably 2% by weight or less. When the content of boron is at least the above lower limit, the conductive layer X becomes harder, and the oxide film on the surface of the electrode and the conductive particles can be removed more effectively, and the connection resistance between the electrodes can be further reduced. When the content of boron is at most 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.

Further, the surface of the conductive layer X containing nickel and boron has a high magnetic property, and when the electrodes are electrically connected to each other, the electrodes adjacent to each other in the lateral direction are affected by the conductive particles agglomerated by the magnetic properties. The tendency to connect easily. Since the conductive layer X contains nickel, boron, and the above-described metal component M, the magnetic properties of the surface of the conductive layer X are remarkably lowered. Therefore, aggregation of a plurality of conductive particles can be suppressed. Therefore, when the electrodes are electrically connected to each other, it is possible to suppress the connection between the adjacent electrodes in the lateral direction due to the aggregated conductive particles. That is, the short circuit between adjacent electrodes can be further prevented.

Further, 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 and the electrodes are connected to each other, an appropriate indentation can be formed on the electrode. Further, when the conductive layer X contains at least one of tungsten and molybdenum or contains boron, the conductive layer X is remarkably hard, and as a result, even if the connection structure is connected to the connection structure between the electrodes by the conductive particles, It is also not easy to cause poor conduction. That is, the impact resistance of the connection structure can also be improved.

The content of the metal component M (the total content of tungsten and molybdenum) in 100% by weight of the entire conductive layer X is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, still more preferably 0.2% by weight or more, and further It is preferably 0.5% by weight or more, more preferably 1% by weight or more, still more preferably 5% by weight or more, and most preferably 10% by weight or more. When the content of the metal component M is at least the above lower limit, the hardness of the outer surface of the conductive layer is further improved. Therefore, when an 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 particle can be effectively removed, and the resin component between the electrode and the conductive particle can be effectively removed. connection The electric resistance is lowered, and the impact resistance of the obtained joined structure is improved. Further, when the content of the metal component M is at least the above lower limit, the magnetic properties of the outer surface of the conductive layer X are weakened, and aggregation of a plurality of conductive particles is less likely to occur. Therefore, the short circuit between the electrodes can be effectively suppressed.

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 by the content of nickel and boron. The content of the metal component M in 100% by weight of the entire conductive layer X is preferably 40% by weight or less, more preferably 30% by weight or less, further preferably 25% by weight or less, and particularly preferably 20% by weight or less.

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

The nickel and the metal component M in the entire 100% by weight of the conductive layer X in terms of effectively reducing the initial connection resistance between the electrodes The more the total content, the better. Therefore, the total content of nickel and the metal component M in 100% by weight of the entire conductive layer X is preferably 75.1% by weight or more, more preferably 80.1% by weight or more, still more preferably 85.1% by weight or more, and particularly preferably 90.1% by weight or more, 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, or 97.6% by weight or more, or 98.1% by weight or more.

In view of further reducing the connection resistance between the electrodes, 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 the entire 100% by weight of the conductive layer X is less than 1% by weight. . Further, in view of further reducing the connection resistance between the electrodes, it is more preferable that the conductive layer X does not contain phosphorus, or the conductive layer X contains phosphorus and the content of phosphorus in the entire 100% by weight of the conductive layer X is less than 0.5% by weight. . From the viewpoint of more 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 content of phosphorus is at most the above upper limit, when the electrodes are connected to each other, the oxide film on the surface of the electrode and the conductive particles can be more effectively removed. As a result, the connection resistance between the electrodes can be reduced. Further, since the resin component between the electrode and the conductive particles can be effectively removed, the connection resistance between the electrodes is further lowered. In order to remarkably reduce the connection resistance between the electrodes, it is particularly preferable that the above-mentioned conductive layer X does not contain phosphorus.

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

Further, when the conductive layer X contains the metal component M and the content of phosphorus is not more than the above upper limit, the conductive layer X is remarkably hard, and as a result, even a connection structure in which electrodes are connected by an electroconductive particle is impacted. It is also not easy to cause poor conduction. That is, the impact resistance of the connection structure can also be improved.

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

When the respective contents of nickel, boron, tungsten, molybdenum and phosphorus in the conductive layer X are measured, an ICP (Inductively Coupled Plasma) emission spectrometer is preferably used. As a commercial item of the ICP emission spectrum analyzer, an ICP emission spectrum analyzer manufactured by HORIBA Co., Ltd., etc. are mentioned. Further, when measuring the respective contents of nickel, boron, tungsten, molybdenum and phosphorus in the conductive layer X, an ICP-MS (Inductively Coupled Plasma Mass Spectrometry) 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, lanthanum, cerium, lanthanum, cerium, cadmium, cerium, Tungsten and these alloys. Again, as the above gold The genus may also include tin-doped indium oxide (ITO) and solder. Among them, an alloy containing tin, nickel, palladium, copper or gold is preferred, and nickel or palladium is more preferred because the connection resistance between the electrodes is further lowered. The metal constituting the other conductive layer preferably contains nickel.

A method of forming a conductive layer (other conductive layer and conductive layer X) on the surface of the substrate particles is not particularly limited. Examples of the method of forming the conductive layer include a method using electroless plating, a method using electroplating, a method using physical vapor deposition, and coating a metal powder or a metal powder on the surface of a substrate particle or another conductive layer. And the method of the adhesive paste, and the like. Among them, the method using electroless plating is preferable because it is relatively simple to form a conductive layer. Examples of the method using physical vapor deposition include vacuum 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, and more preferably 1000 μm or less, and more preferably 500 μm or less. More preferably, it is 300 μm or less, further preferably 100 μm or less, further preferably 50 μm or less, particularly preferably 30 μm or less, further preferably 20 μm or less, and most preferably 5 μm or less. When the particle diameter of the conductive particles is not less than the above lower limit and not more than the above upper limit, when the electrodes are connected by using the conductive particles, the contact area between the conductive particles and the electrode is sufficiently increased, and aggregation is less likely to occur when the conductive layer is formed. Conductive particles. Moreover, the interval between the electrodes connected via the conductive particles is not excessively large, and the conductive layer is not easily peeled off from the surface of the substrate particles.

Further, when used for a conductive material such as an anisotropic conductive material, the particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, and is preferably 100 μm or less, and 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, when the electrodes are connected by using the conductive particles, the contact area between the conductive particles and the electrode is sufficiently increased, and aggregation is less likely to occur when the conductive layer is formed. Conductive particles. Moreover, the interval between the electrodes connected via the conductive particles is not excessively large, and the conductive layer is not easily peeled off from the surface of the substrate particles.

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

The thickness of the conductive layer X is preferably 0.005 μm or more, more preferably 0.01 μm or more, further preferably 0.05 μm or more, and 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 are not excessively hard, and the conductive particles can be sufficiently deformed when the electrodes are connected to each other.

In the case where 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, further preferably 0.05 μm or more, and preferably 0.5 μm or less. It is preferably 0.3 μm or less, and more 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 of the conductive layer X can be made uniform, and the connection resistance between the electrodes can be sufficiently lowered.

In the case where the conductive layer is a double layer or more laminated structure, the conductive layer is included The thickness of the entire conductive layer inside X is preferably 0.001 μm or more, more preferably 0.01 μm or more, further preferably 0.05 μm or more, particularly preferably 0.1 μm or more, and preferably 1 μm or less, more preferably 0.5 or less. It is preferably not more than μm, more preferably 0.3 μm or less, 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 entire conductive layer can be uniformly coated, and the connection resistance between the electrodes can be sufficiently lowered.

The thickness of the conductive layer X is particularly preferably 0.05 μm or more and 0.5 μm or less. Further, it is particularly 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 0.5 μm or less. The thickness of the conductive layer X is preferably 0.05 μm or more and 0.3 μm or less. Further, it is 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 the thickness of the above-mentioned preferred conductive layer X and the particle diameter of the substrate particles are satisfied, the conductive particles can be more suitably used for applications in which a large current flows. Further, when the conductive particles are compressed and the electrodes are connected to each other, the electrode damage can be further suppressed.

The thickness of the conductive layer X and the thickness of the entire conductive layer can be measured, for example, by observing a cross section of the conductive particles using 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 the conductive layer X is formed by electroless nickel plating is exemplified; a method for adjusting a concentration of a boron-containing reducing agent when forming a conductive layer X by electroless nickel plating; a method of adjusting a tungsten concentration in a nickel plating solution; and a method of adjusting a concentration of molybdenum in the nickel plating solution; A method of adjusting the nickel salt concentration in the nickel plating solution.

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

In the above-described catalytic treatment step, a catalyst is formed on the surface of the resin particles, and the catalyst serves as a starting point for forming a plating layer by electroless plating.

As a method of forming the above-mentioned catalyst on the surface of the resin particles, for example, a method of adding a resin particle to a solution containing palladium chloride and tin chloride and then activating the surface of the resin particle by an acid solution or an alkali solution may be mentioned. Palladium is deposited on the surface of the resin particles; and after the resin particles are added to the solution containing palladium sulfate and aminopyridine, the surface of the resin particles is activated by a solution containing a reducing agent to precipitate palladium on the surface of the resin particles. Method, etc. As the reducing agent, a boron-containing reducing agent can be preferably used. Among them, 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 at least one of a nickel salt, a tungsten-containing compound, and a molybdenum-containing compound, and the boron-containing reducing agent may be used. By immersing the resin particles in a nickel plating bath, nickel can be deposited on the surface of the catalyst-forming resin particles, 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 of the present invention preferably have protrusions on the surface. Preferably, the conductive layer including the conductive layer X has protrusions on the outer surface, and it is preferable that the conductive layer X has protrusions on the outer surface. An oxide film is often formed on the surface of the electrode connected by the conductive particles. Further, an oxide film is formed on the surface of the conductive layer of the conductive particles. When the conductive particles having the protrusions are used, the conductive particles are placed between the electrodes and then pressure-bonded, whereby the oxide film can be effectively removed by the protrusions. Therefore, the electrode can be brought into more sure contact with the conductive particles, and the connection resistance between the electrodes can be reduced. Further, when the surface of the conductive particles has an insulating material, or when the conductive particles are dispersed in the binder resin and used as a conductive material, the conductive particles can be effectively removed by the protrusions of the conductive particles. The resin between the electrodes. Therefore, the conduction reliability between the electrodes is improved.

The above protrusions are preferably plural. The number of protrusions on the outer surface of the above-mentioned conductive layer in each of the above-mentioned conductive particles is preferably three or more, and more preferably five or more. The upper limit of the number of the above protrusions is not particularly limited. The upper limit of the number of the protrusions can be appropriately selected in consideration of the particle diameter of the conductive particles and the like.

[core material]

By embedding the core material in the conductive layer, the conductive layer is easily provided with 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, it is not necessary to use a core material.

Examples of the method for forming the protrusion include a method in which a core material is adhered to the surface of the substrate particle, and then a conductive layer is formed by electroless plating; and electroless plating is formed on the surface of the substrate particle. After the conductive layer, the core material is attached, and the conductive layer is formed by electroless plating.

As a method of disposing the core material on the surface of the substrate particle, for example, a method of adding a conductive substance to be a core material to a dispersion of the substrate particles, for example, by Van der Waals The core material is accumulated and adhered to the surface of the substrate particles; and the conductive material serving as the core material is added to the container containing the substrate particles, and the core material is attached to the substrate particles by mechanical action such as rotation of the container. surface. Among them, the method of accumulating and adhering the core material to the surface of the substrate particles in the dispersion liquid is preferable because it is easy to control the amount of the core material to be attached.

Examples of the conductive material constituting the core material include a metal, a metal oxide, a conductive non-metal such as graphite, and a conductive polymer. Examples of the conductive polymer include polyacetylene and the like. Among them, metal is preferable because it can improve conductivity and can effectively reduce the connection resistance. The core material is preferably a metal particle.

Examples of the metal include metals such as gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, ruthenium, osmium, iridium, and cadmium, and tin-lead. An alloy containing two or more kinds of metals such as an alloy, a tin-copper alloy, a tin-silver alloy, and a tin-lead-silver alloy. Among them, nickel, copper, silver or gold is preferred. The metal constituting the core material may be the same as or different from the metal constituting the above-mentioned conductive layer. The metal constituting the core material preferably contains a metal constituting the above-mentioned conductive layer. The metal constituting the above core material preferably contains nickel. The metal constituting the above core material preferably contains nickel.

The shape of the core material is not particularly limited. The shape of the core material is preferably a block shape. Examples of the core material include a particulate block, agglomerates in which a plurality of fine particles are aggregated, and an amorphous block.

The average diameter (average particle diameter) of the core material is preferably 0.001 μm or more, more preferably 0.05 μm or more, and is preferably 0.9 μm or less, more preferably 0.2 μm or less. When the average diameter of the core material 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 above-mentioned core substance means a number average diameter (number average particle diameter). The average diameter of the core material can be determined by observing an arbitrary 50 core materials by an electron microscope or an optical microscope and calculating an average value.

[insulating substance]

The conductive particles of the present invention preferably comprise an insulating material disposed on the surface of the conductive layer. In this case, when the conductive particles are used for the connection between the electrodes, the short circuit between the adjacent electrodes can be prevented. Specifically, when a plurality of conductive particles are in contact with each other, an insulating material exists between the plurality of electrodes, so that a short circuit between the adjacent electrodes in the lateral direction and not between the upper and lower electrodes can be prevented. Further, when the electrodes are connected to each other, the conductive particles between the conductive layers of the conductive particles and the electrodes can be easily removed by pressurizing the conductive particles with the two electrodes. 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.

The insulating material is preferably an insulating particle because the insulating material can be more easily removed when the electrodes are pressure-bonded.

Specific examples of the insulating resin as the material of the insulating material include a polyolefin, a (meth) acrylate polymer, a (meth) acrylate copolymer, a block polymer, a thermoplastic resin, and a thermoplastic resin. Union Materials, thermosetting resins, water-soluble resins, and the like.

Examples of the polyolefins include polyethylene, an ethylene-vinyl acetate copolymer, and an ethylene-acrylate copolymer. Examples of the (meth) acrylate polymer include poly(methyl) acrylate, poly(ethyl) acrylate, and poly(meth) acrylate. Examples of the block polymer include polystyrene, styrene-acrylate copolymer, styrene-butadiene (styrene-butadiene) type styrene-butadiene block copolymer, and SBS ( Styrene-butadiene-styrene, styrene-butadiene-styrene type styrene-butadiene block copolymer, and the like, and the like. Examples of the thermoplastic resin include a vinyl polymer and a vinyl copolymer. Examples of the thermosetting resin include an epoxy resin, a phenol resin, and a melamine resin. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polypropylene decylamine, polyvinylpyrrolidone, polyethylene oxide, and methyl cellulose. Among them, a water-soluble resin is preferred, and polyvinyl alcohol is more preferred.

Examples of the method of disposing the insulating material on the surface of the conductive layer include chemical methods, physical or mechanical methods, and the like. 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, spray, immersion, and vacuum evaporation. Among them, a method of disposing the insulating material on the surface of the conductive layer via a chemical bond is preferred because the insulating material is not easily detached.

The average diameter (average particle diameter) of the above insulating material may be based on conductive particles The particle size and the use of the conductive particles are appropriately selected. The average diameter (average particle diameter) of the insulating material is preferably 0.005 μm or more, more preferably 0.01 μm or more, and is preferably 1 μm or less, and more preferably 0.5 μm or less. When the average diameter of the insulating material is at least the above lower limit, when the conductive particles are dispersed in the binder resin, the conductive layers of the plurality of conductive particles are less likely to contact each other. When the average diameter of the insulating particles is not more than the above upper limit, when the electrodes are connected to each other, the insulating material between the electrodes and the conductive particles is excluded, and it is not necessary to excessively increase the pressure, and high-temperature heating is not required.

The "average diameter (average particle diameter)" of the above insulating material means a number average diameter (number average particle diameter). The average diameter of the insulating material can be determined by using a particle size distribution measuring device or the like.

(conductive material)

The conductive material of the present invention contains the above-mentioned conductive particles and a binder resin. The conductive particles of the present invention are preferably used as a conductive material in a binder resin. The conductive material of the present invention is preferably an anisotropic conductive material.

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

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

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

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

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

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

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

(connection structure)

The connection structure can be obtained by using the conductive particles of the present invention or by connecting the connection member using a conductive material containing the conductive particles and the binder resin.

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

Fig. 4 is a view showing a connection structure in which the conductive particles according to the first embodiment of the present invention are used in a schematic manner and in a front cross-sectional view.

The connection structure 51 shown in FIG. 4 includes the first connection object member 52, the second connection object member 53, and the connection portion 54 that connects the first and second connection object members 52 and 53. The connecting portion 54 is formed by curing the conductive material containing the conductive particles 1. In addition, in FIG. 4, the electroconductive particle 1 is shown in a schematic diagram for convenience of illustration.

The first connection object member 52 has a plurality of electrodes 52b on the upper surface 52a (surface). The second connection object member 53 has a plurality of electrodes 53b on the lower surface 53a (surface). The electrode 52b and the electrode 53b 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 method for producing the above-described connection structure is not particularly limited. An example of the method of manufacturing the connection structure is a method in which the conductive material is placed between the first connection target member and the second connection target member to obtain a laminate, and the laminate is heated and pressurized. The pressure of the above pressurization is about 9.8 × 10 ⁴ to 4.9 × 10 ⁶ Pa. The heating temperature is about 120 to 220 °C.

Specific examples of the connection target member include electronic components such as a semiconductor wafer, a capacitor, and a diode, and a printed circuit board and flexibility. A circuit board such as a printed circuit board or a glass substrate. The conductive material is preferably a conductive material for connecting electronic components. The conductive material is preferably a paste-like conductive paste applied to the member to be joined in a paste 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. In the case where the connection target member is a flexible printed circuit board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode or a copper electrode. In the case where the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode or a tungsten electrode. Further, in the case where the electrode is an aluminum electrode, it may be an electrode formed only of aluminum, or an electrode having an aluminum layer on a surface layer of the metal oxide layer. Examples of the material of the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al, Ga, and the like.

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

(Example 1)

A divinylbenzene copolymer resin particle ("Micropearl SP-203" manufactured by Sekisui Chemical Co., Ltd.) having a particle diameter of 3.0 μm was prepared.

10 parts by weight of the above resin particles were dispersed in 100 parts by weight of an alkali solution containing 5 wt% of a palladium catalyst solution using an ultrasonic disperser, and then the solution was filtered to take out the resin particles. Then, the resin particles were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surface of the resin particles. After the surface-activated resin particles are sufficiently washed with water, 500 weight of distilled water is added. The fraction was dispersed to thereby 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 the obtained suspension was stirred at 60 ° C, the nickel plating solution was gradually added dropwise to the suspension to carry out electroless nickel plating. Thereafter, the particles were taken out by filtration of the suspension, washed with water, and dried to obtain conductive particles in which a nickel-boron-tungsten conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles.

(Example 2)

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 in the same manner as in Example 1 except that the concentration of sodium tungstate was changed to 0.12 mol/L.

(Example 3)

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 in the same manner as in Example 1 except that the concentration of sodium tungstate was changed to 0.23 mol/L.

(Example 4)

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 in the same manner as in Example 1 except that the concentration of sodium tungstate was changed to 0.35 mol/L.

(Example 5)

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

(Example 6)

(1) Palladium attachment step

Divinyl benzene resin particles ("Micropearl SP-205" manufactured by Sekisui Chemical Co., Ltd.) having a particle diameter of 5.0 μm were prepared. The resin particles were etched and washed with water. Next, the resin particles were added to 100 mL of a palladium catalyst solution containing 8 wt% of a palladium catalyst, and stirred. Thereafter, it was filtered and washed. The resin particles were added to a 0.5 wt% dimethylamine borane solution having a pH of 6, to obtain resin particles to which palladium adhered.

(2) Core substance attachment step

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

(3) Electroless nickel plating step

In the same manner as in Example 1, 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 7)

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 in the same manner as in Example 6 except that the concentration of sodium tungstate was changed to 0.35 mol/L.

(Example 8)

(1) Production of insulating particles

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

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

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

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

(Example 9)

A nickel-boron-tungsten conductive layer (thickness) was formed on the surface of the resin particles in the same manner as in Example 1 except that the sodium tungstate concentration was changed to 0.46 mol/L. Conductive particles of 0.1 μm).

(Embodiment 10)

In the same manner as in Example 1, except that the concentration of dimethylamine borane was changed to 4.60 mol/L, and the concentration of sodium tungstate was changed to 0.23 mol/L, nickel-boron-tungsten was disposed on the surface of the resin particles in the same manner as in Example 1. Conductive layer (thickness 0.1 μm) of conductive particles.

(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 disposed on the surface of the resin particles. Conductive particles (0.1 μm thick) of conductive particles. The content of phosphorus in 100% by weight of the entire conductive layer was 8.9% by weight.

(Comparative Example 2)

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

(Example 11)

A divinylbenzene copolymer resin particle ("Micropearl SP-203" manufactured by Sekisui Chemical Co., Ltd.) having a particle diameter of 3.0 μm was prepared.

10 parts by weight of the above resin particles were dispersed in 100 parts by weight of an alkali solution containing 5 wt% of a palladium catalyst solution using an ultrasonic disperser, and then the solution was filtered to take out the resin particles. Then, the resin particles were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surface of the resin particles. After the surface-activated resin particles are sufficiently washed with water, 500 weight of distilled water is added. The fraction was dispersed to thereby 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 the obtained suspension was stirred at 60 ° C, the nickel plating solution was gradually added dropwise to the suspension to carry out electroless nickel plating. Thereafter, the particles were taken out by filtration of the suspension, washed with water, and dried to obtain conductive particles in which a nickel-boron-molybdenum conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles.

(Embodiment 12)

Conductive particles in which a nickel-boron-molybdenum conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles were obtained in the same manner as in Example 11 except that the sodium molybdate concentration was changed to 0.12 mol/L.

(Example 13)

Conductive particles in which a nickel-boron-molybdenum conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles were obtained in the same manner as in Example 11 except that the sodium molybdate concentration was changed to 0.23 mol/L.

(Example 14)

Conductive particles in which a nickel-boron-molybdenum conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles were obtained in the same manner as in Example 11 except that the sodium molybdate concentration was changed to 0.35 mol/L.

(Example 15)

The same procedure as in Example 11 was carried out except that the concentration of dimethylamine borane was changed to 2.76 mol/L, and the concentration of sodium molybdate was changed to 0.35 mol/L. Conductive particles of a nickel-boron-molybdenum conductive layer (thickness: 0.1 μm) were disposed on the surface of the resin particles.

(Embodiment 16)

(1) Palladium attachment step

Divinyl benzene resin particles ("Micropearl SP-205" manufactured by Sekisui Chemical Co., Ltd.) having a particle diameter of 5.0 μm were prepared. The resin particles were etched and washed with water. Next, the resin particles were added to 100 mL of a palladium catalyst solution containing 8 wt% of a palladium catalyst, and stirred. Thereafter, it was filtered and washed. The resin particles were added to a 0.5 wt% dimethylamine borane solution having a pH of 6, to obtain resin particles to which palladium adhered.

(2) Core substance attachment step

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

(3) Electroless nickel plating step

Conductive particles in which a nickel-boron-molybdenum conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles were obtained in the same manner as in Example 11.

(Example 17)

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

(Embodiment 18)

(1) Production of insulating particles

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

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

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

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

(Embodiment 19)

A nickel-boron-molybdenum conductive layer was disposed on the surface of the resin particles in the same manner as in Example 11 except that the sodium molybdate concentration was changed to 0.46 mol/L. Conductive particles (thickness 0.1 μm).

(Embodiment 20)

In the same manner as in Example 11, except that the concentration of dimethylamine borane was changed to 4.60 mol/L, and the concentration of sodium molybdate was changed to 0.23 mol/L, nickel-boron-molybdenum was disposed on the surface of the resin particles in the same manner as in Example 11. Conductive layer (thickness 0.1 μm) of conductive particles.

(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 disposed on the surface of the resin particles. Conductive particles (0.1 μm thick) of conductive particles. The content of phosphorus in 100% by weight of the entire conductive layer was 9.5% by weight.

(Evaluation of Examples 1 to 20 and Comparative Examples 1 to 3)

(1) Compressive elastic modulus of conductive particles (5% K value)

The compression elastic modulus (5% K value) of the obtained conductive particles was measured using a micro compression tester ("Fischerscope H-100" manufactured by Fischer Co., Ltd.).

(2) Crack generation test of conductive layer

Conductive particles are placed on the stage. Using a micro compression tester (Fischerscope H-100 manufactured by Fischer), a cylinder (diameter 50 μm, made of diamond) was used as a compression member at a compression speed of 0.33 mN/s and a maximum test load of 10 mN. The smooth end surface of the compression member is lowered toward the conductive particles. The conductive particles are compressed by smooth end faces. The compression is performed until a crack occurs in the conductive layer of the conductive particles. Conductive layer The above-described compression displacement of the particle diameter of the conductive particles which generate cracks with respect to the conductive particles before compression in the compression direction is shown in Tables 1 and 2 below. As a result of the evaluation of the above-described compression displacement, the average value of the measured values of the three conductive particles is shown in Tables 1 and 2 below.

(3) The content of nickel, boron, phosphorus, tungsten and molybdenum in 100% by weight of the entire conductive layer X

5 g of conductive particles were added to a mixture of 5 mL of 60% nitric acid and 10 mL of 37% hydrochloric acid to completely dissolve the conductive layer to obtain a solution. Using the obtained solution, the contents of nickel, boron, phosphorus, tungsten, and molybdenum were analyzed by an ICP-MS analyzer (manufactured by Hitachi, Ltd.). Further, the conductive layer of the conductive particles of the examples does not contain phosphorus.

(4) Plating state

The plating state of 50 obtained conductive particles was observed by a scanning electron microscope. Observe the presence or absence of uneven plating such as plating cracks or plating peeling. When it was confirmed that the number of the conductive particles having uneven plating was four or less, it was judged as "good", and it was judged that the number of the conductive particles having uneven plating was five or more.

(5) Agglutination state

10 parts by weight of bisphenol A type epoxy resin ("Epikote 1009" manufactured by Mitsubishi Chemical Corporation), 40 parts by weight of acrylic rubber (weight average molecular weight: about 800,000), 200 parts by weight of methyl ethyl ketone, and microcapsule type 50 parts by weight of a hardener ("HX3941HP" manufactured by Asahi Kasei Chemicals Co., Ltd.) and 2 parts by weight of a decane coupling agent ("SH6040" manufactured by Dow Corning Toray Silicone Co., Ltd.) were mixed, and conductive particles were added so as to have a content of 3% by weight. It is dispersed to obtain an anisotropic conductive material.

The obtained anisotropic conductive material was stored at 25 ° C for 72 hours. After storage, it was evaluated whether or not agglomerated conductive particles precipitated in the anisotropic conductive material. The case where the non-aggregated conductive particles were precipitated was judged as "good", and the case where the aggregated conductive particles were precipitated was judged as "poor".

(6) Connection resistance

Production of a connection structure: 10 parts by weight of bisphenol A type epoxy resin ("Epikote 1009" manufactured by Mitsubishi Chemical Corporation), 40 parts by weight of acrylic rubber (weight average molecular weight: about 800,000), and methyl ethyl ketone 200 50 parts by weight of a microcapsule-type hardener ("HX3941HP" manufactured by Asahi Kasei Chemicals Co., Ltd.) and 2 parts by weight of a decane coupling agent ("SH6040" manufactured by Dow Corning Toray Silicone Co., Ltd.) were mixed in a weight ratio of 3% by weight. The conductive particles were added and dispersed to obtain a resin composition.

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

The obtained anisotropic conductive film was cut into a size of 5 mm × 5 mm. The cut anisotropic conductive film was attached to a glass substrate (having a height of 0.2 μm, L/S=20 μm/20 μm) including a guide wire for resistance measurement on one side (width 3 cm) The center of the aluminum electrode side, 3 cm long. Then, a two-layer flexible printed circuit board (width 2 cm, length 1 cm) including the same aluminum electrode was aligned and bonded so that the electrodes overlap each other. The glass substrate and the double were pressed at 10 N, 180 ° C and 20 seconds. The laminate of the layer of the flexible printed circuit board is thermocompression bonded to obtain a bonded structure. Further, a two-layer flexible printed circuit board in which an aluminum electrode is directly formed on a polyimide film is used.

Measurement of connection resistance: The connection resistance between the opposing electrodes in the obtained connection structure was measured by a four-terminal method. Further, the connection resistance was determined based on the following criteria.

[Determination of connection resistance]

○○: The connection resistance is 2.0 Ω or less

○: The connection resistance exceeds 2.0 Ω and is 3.0 Ω or less.

△: The connection resistance exceeds 3.0 Ω and is 5.0 Ω or less.

×: The connection resistance exceeds 5.0 Ω

(7) Impact resistance

The connection structure obtained by the evaluation of the connection resistance of the above (6) was dropped from a position of 70 cm in height, and the conduction state was confirmed, whereby the impact resistance was evaluated. When the resistance value was 50% or less from the initial resistance value, it was judged as "good", and the case where the resistance value was increased from the initial resistance value by more than 50% was judged as "poor".

(8) With or without indentation formation

Using the differential interference microscope, the electrode provided on the glass substrate was observed from the side of the glass substrate of the bonded structure obtained in the evaluation of the connection resistance of the above (6), and the presence or absence of the indentation of the electrode in contact with the conductive particles was determined based on the following criteria. Further, regarding the presence or absence of the formation of the indentation of the electrode, the observation was performed by a differential interference microscope so that the electrode area was 0.02 mm ² , and the number of indentations per 0.02 mm ² of the electrode was calculated. The arbitrary interference was observed by a differential interference microscope, and the average value of the number of indentations per 0.02 mm ² of the electrode was calculated.

[There is no basis for the formation of indentation]

○○: The number of indentations per 0.02 mm ² of the electrode is 25 or more

○: The number of indentations per 0.02 mm ² of the electrode is 20 or more and less than 25

△: The number of indentations per 0.02 mm ² of the electrode is 5 or more and less than 20

×: The number of indentations per 0.02 mm ² of the electrode is less than 5

The results are shown in Tables 1 and 2 below.

Further, the conductive particles of Examples 21 to 40 and Comparative Examples 4 to 6 were produced separately from the conductive particles of Examples 1 to 20 and Comparative Examples 1 to 3.

(Example 21)

A divinylbenzene copolymer resin particle ("Micropearl SP-203" manufactured by Sekisui Chemical Co., Ltd.) having a particle diameter of 3.0 μm was prepared.

10 parts by weight of the above resin particles were dispersed in 100 parts by weight of an alkali solution containing 5 wt% of a palladium catalyst solution using an ultrasonic disperser, and then the solution was filtered to take out the resin particles. Then, the resin particles were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surface of the resin particles. The surface-activated resin particles were sufficiently washed with water, and then added to 500 parts by weight of distilled water to be dispersed, thereby obtaining 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 the obtained suspension was stirred at 60 ° C, the nickel plating solution was gradually added dropwise to the suspension to carry out electroless nickel plating. Thereafter, the particles were taken out by filtration of the suspension, washed with water, and dried to obtain conductive particles in which a nickel-boron-tungsten conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles.

(Example 22)

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 in the same manner as in Example 21 except that the sodium tungstate concentration was changed to 0.12 mol/L.

(Example 23)

Except that the concentration of sodium tungstate was changed to 0.23 mol/L, and Example 21 In the same manner, 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 24)

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 in the same manner as in Example 21 except that the concentration of sodium tungstate was changed to 0.35 mol/L.

(Embodiment 25)

A nickel-boron-tungsten was disposed 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 layer (thickness 0.1 μm) of conductive particles.

(Example 26)

(1) Palladium attachment step

Divinyl benzene resin particles ("Micropearl SP-205" manufactured by Sekisui Chemical Co., Ltd.) having a particle diameter of 5.0 μm were prepared. The resin particles were etched and washed with water. Next, the resin particles were added to 100 mL of a palladium catalyst solution containing 8 wt% of a palladium catalyst, and stirred. Thereafter, it was filtered and washed. The resin particles were added to a 0.5 wt% dimethylamine borane solution having a pH of 6, to obtain resin particles to which palladium adhered.

(2) Core substance attachment step

The resin particles to which palladium adhered were stirred for 3 minutes in 300 mL of ion-exchanged water to obtain a dispersion. Next, 1 g of a metal nickel particle slurry (average particle diameter: 100 nm) was added to the above dispersion liquid for 3 minutes to obtain resin particles to which a core substance 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) was disposed on the surface of the resin particles were obtained in the same manner as in Example 26 except that the concentration of sodium tungstate was changed to 0.35 mol/L.

(Embodiment 28)

(1) Production of insulating particles

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

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

10 g of the conductive particles obtained in Example 26 was dispersed in 500 mL of ion-exchanged water, 4 g of an aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 6 hours. After filtering with a 3 μm mesh filter, it is washed with methanol and dried to obtain conductive particles to which insulating particles are attached. child.

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

(Example 29)

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 in the same manner as in Example 21 except that the concentration of sodium tungstate was changed to 0.46 mol/L.

(Embodiment 30)

A nickel-boron-tungsten was disposed 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 layer (thickness 0.1 μm) of conductive particles.

(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 disposed on the surface of the resin particles. Conductive particles (0.1 μm thick) of conductive particles. The content of phosphorus in 100% by weight of the entire conductive layer was 8.7% by weight.

(Comparative Example 5)

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, nickel and boron were disposed on the surface of the resin particles. Conductive particles (0.1 μm thick) of conductive particles.

(Example 31)

A divinylbenzene copolymer resin particle ("Micropearl SP-203" manufactured by Sekisui Chemical Co., Ltd.) having a particle diameter of 3.0 μm was prepared.

10 parts by weight of the above resin particles were dispersed in 100 parts by weight of an alkali solution containing 5 wt% of a palladium catalyst solution using an ultrasonic disperser, and then the solution was filtered to take out the resin particles. Then, the resin particles were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surface of the resin particles. The surface-activated resin particles were sufficiently washed with water, and then added to 500 parts by weight of distilled water to be dispersed, thereby obtaining 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 the obtained suspension was stirred at 60 ° C, the nickel plating solution was gradually added dropwise to the suspension to carry out electroless nickel plating. Thereafter, the particles were taken out by filtration of the suspension, washed with water, and dried to obtain conductive particles in which a nickel-boron-molybdenum conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles.

(Example 32)

Conductive particles in which a nickel-boron-molybdenum conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles were obtained in the same manner as in Example 31 except that the sodium molybdate concentration was changed to 0.12 mol/L.

(Example 33)

Except that the sodium molybdate concentration was changed to 0.23 mol/L, and Example 31 In the same manner, conductive particles in which a nickel-boron-molybdenum conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles were obtained.

(Example 34)

Conductive particles in which a nickel-boron-molybdenum conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles were obtained in the same manner as in Example 31 except that the sodium molybdate concentration was changed to 0.35 mol/L.

(Example 35)

In the same manner as in Example 31 except that the concentration of dimethylamine borane was changed to 2.76 mol/L, and the concentration of sodium molybdate was changed to 0.35 mol/L, nickel-boron-molybdenum was disposed on the surface of the resin particles in the same manner as in Example 31. Conductive layer (thickness 0.1 μm) of conductive particles.

(Example 36)

(1) Palladium attachment step

Divinyl benzene resin particles ("Micropearl SP-205" manufactured by Sekisui Chemical Co., Ltd.) having a particle diameter of 5.0 μm were prepared. The resin particles were etched and washed with water. Next, the resin particles were added to 100 mL of a palladium catalyst solution containing 8 wt% of a palladium catalyst, and stirred. Thereafter, it was filtered and washed. The resin particles were added to a 0.5 wt% dimethylamine borane solution having a pH of 6, to obtain resin particles to which palladium adhered.

(2) Core substance attachment step

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

(3) Electroless nickel plating step

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

(Example 37)

Conductive particles in which a nickel-boron-molybdenum conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles were obtained in the same manner as in Example 36 except that the sodium molybdate concentration was changed to 0.35 mol/L.

(Example 38)

(1) Production of insulating particles

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

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

10 g of the conductive particles obtained in Example 36 was dispersed in 500 mL of ion-exchanged water, 4 g of an aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 6 hours. After filtering with a 3 μm mesh filter, it is washed with methanol and dried to obtain conductive particles to which insulating particles are attached. child.

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

(Example 39)

Conductive particles in which a nickel-boron-molybdenum conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles were obtained in the same manner as in Example 31 except that the sodium molybdate concentration was changed to 0.46 mol/L.

(Embodiment 40)

In the same manner as in Example 31 except that the concentration of dimethylamine borane was changed to 4.60 mol/L, and the concentration of sodium molybdate was changed to 0.23 mol/L, nickel-boron-molybdenum was disposed on the surface of the resin particles in the same manner as in Example 31. Conductive layer (thickness 0.1 μm) of conductive particles.

(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 disposed on the surface of the resin particles. Conductive particles (0.1 μm thick) of conductive particles. The phosphorus content in 100% by weight of the entire conductive layer 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)

Use a micro compression tester (Fischerscope, manufactured by Fischer) H-100") The compression elastic modulus (10% K value) of the obtained conductive particles was measured.

(2) Compressive recovery rate of conductive particles

The compression recovery ratio at which the obtained conductive particles were compressed by 30% was measured using a micro compression tester (Fischerscope H-100 manufactured by Fischer Co., Ltd.).

(3) The content of nickel, boron, phosphorus, tungsten and molybdenum in 100% by weight of the entire conductive layer

5 g of conductive particles were added to a mixture of 5 mL of 60% nitric acid and 10 mL of 37% hydrochloric acid to completely dissolve the conductive layer to obtain a solution. Using the obtained solution, the contents of nickel, boron, phosphorus, tungsten, and molybdenum were analyzed by an ICP-MS analyzer (manufactured by Hitachi, Ltd.). Further, the conductive layer of the conductive particles of the examples does not contain phosphorus.

(4) Plating state

The plating state of 50 obtained conductive particles was observed by a scanning electron microscope. Observe the presence or absence of uneven plating such as plating cracks or plating peeling. When it was confirmed that the number of the conductive particles having uneven plating was four or less, it was judged as "good", and it was judged that the number of the conductive particles having uneven plating was five or more.

(5) Agglutination state

10 parts by weight of bisphenol A type epoxy resin ("Epikote 1009" manufactured by Mitsubishi Chemical Corporation), 40 parts by weight of acrylic rubber (weight average molecular weight: about 800,000), 200 parts by weight of methyl ethyl ketone, and microcapsule type Hardener ("HX3941HP" manufactured by Asahi Kasei Chemicals Co., Ltd.) 50 parts by weight, decane coupling 2 parts by weight of a mixture ("SH6040" manufactured by Dow Corning Toray Silicone Co., Ltd.) was added, and conductive particles were added and dispersed so as to have a content of 3% by weight to obtain an anisotropic conductive material.

The obtained anisotropic conductive material was stored at 25 ° C for 72 hours. After storage, it was evaluated whether or not agglomerated conductive particles precipitated in the anisotropic conductive material. The case where the non-aggregated conductive particles were precipitated was judged as "good", and the case where the aggregated conductive particles were precipitated was judged as "poor".

(6) Initial connection resistance

Production of a connection structure: 10 parts by weight of bisphenol A type epoxy resin ("Epikote 1009" manufactured by Mitsubishi Chemical Corporation), 40 parts by weight of acrylic rubber (weight average molecular weight: about 800,000), and methyl ethyl ketone 200 50 parts by weight of a microcapsule-type hardener ("HX3941HP" manufactured by Asahi Kasei Chemicals Co., Ltd.) and 2 parts by weight of a decane coupling agent ("SH6040" manufactured by Dow Corning Toray Silicone Co., Ltd.) were mixed in a weight ratio of 3% by weight. The conductive particles were added and dispersed to obtain a resin composition.

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

The obtained anisotropic conductive film was cut into a size of 5 mm × 5 mm. The cut anisotropic conductive film was attached to a glass substrate (having a height of 0.2 μm, L/S=20 μm/20 μm) including a guide wire for resistance measurement on one side (width 3 cm) , 3 cm long, the middle of the aluminum electrode side Central. Then, a two-layer flexible printed circuit board (width 2 cm, length 1 cm) including the same aluminum electrode was attached to the position so that the electrodes overlap each other, and then bonded. The laminated body of the glass substrate and the two-layer flexible printed circuit board was thermocompression-bonded under the pressure conditions of 10 N, 180 ° C, and 20 seconds to obtain a bonded structure. Further, a two-layer flexible printed circuit board in which an aluminum electrode is directly formed on a polyimide film is used.

Measurement of connection resistance: The connection resistance between the opposing electrodes in the obtained connection structure was measured by a four-terminal method. Further, the initial connection resistance was determined based on the following criteria.

[Determination of connection resistance]

○○: The connection resistance is 2.0 Ω or less

○: The connection resistance exceeds 2.0 Ω and is 3.0 Ω or less.

△: The connection resistance exceeds 3.0 Ω and is less than 4.0 Ω.

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

×: The connection resistance exceeds 5.0 Ω

(7) Connecting resistance after high temperature and high humidity test

The bonded structure obtained in the production of the above (6) joined structure was allowed to stand at 85 ° C and a humidity of 85% for 100 hours. The connection resistance between the electrodes of the connected structure after standing was measured by a four-terminal method, and the obtained measured value was made into the connection resistance after high temperature and high humidity test. Further, the connection resistance after the high-temperature and high-humidity test was determined based on the following criteria.

[Determination of connection resistance]

○○: The connection resistance is 2.0 Ω or less

○: The connection resistance exceeds 2.0 Ω and is 3.0 Ω or less.

△: The connection resistance exceeds 3.0 Ω and is less than 4.0 Ω.

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

×: The connection resistance exceeds 5.0 Ω

(8) Impact resistance

The connection structure obtained in the production of the above-mentioned (6) connection structure was dropped from a position of 70 cm in height, and the conduction state was confirmed, whereby the impact resistance was evaluated. When the resistance value was 50% or less from the initial resistance value, it was judged as "good", and the case where the resistance value was increased from the initial resistance value by more than 50% was judged as "poor".

(9) Whether there is indentation formation

The electrode provided on the glass substrate was observed from the side of the glass substrate of the connection structure obtained in the production of the above-mentioned (6) connection structure by using a differential interference microscope, and the presence or absence of indentation of the electrode in contact with the conductive particles was determined by the following criteria. . Further, regarding the presence or absence of the formation of the indentation of the electrode, the observation was performed by a differential interference microscope so that the electrode area was 0.02 mm ² , and the number of indentations per 0.02 mm ² of the electrode was calculated. The arbitrary interference was observed by a differential interference microscope, and the average value of the number of indentations per 0.02 mm ² of the electrode was calculated.

[There is no basis for the formation of indentation]

○○: The number of indentations per 0.02 mm ² of the electrode is 25 or more

○: The number of indentations per 0.02 mm ² of the electrode is 20 or more and less than 25

△: The number of indentations per 0.02 mm ² of the electrode is 5 or more and less than 20

×: The number of indentations per 0.02 mm ² of the electrode is 1 or more and less than 5

××: 0 indentations per 0.02 mm ² of the electrode

The results are shown in Tables 3 and 4 below.

1‧‧‧Electrical particles

1a‧‧‧ Protrusion

2‧‧‧Substrate particles

3‧‧‧ Conductive layer

3a‧‧‧ Protrusion

4‧‧‧ core material

5‧‧‧Insulating substances

11‧‧‧Electrical particles

11a‧‧‧ Protrusion

12‧‧‧2nd conductive layer

13‧‧‧ Conductive layer

13a‧‧‧Protrusion

21‧‧‧Electrical particles

22‧‧‧ Conductive layer

22a‧‧‧ crack

51‧‧‧Connection structure

52‧‧‧1st connection object component

52a‧‧‧above

52b‧‧‧electrode

53‧‧‧2nd connection object component

53a‧‧‧ below

53b‧‧‧electrode

54‧‧‧Connecting Department

71‧‧‧

72‧‧‧Compressed components

72a‧‧‧Smooth end face

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

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

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

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

Fig. 5 is a schematic cross-sectional view for explaining a state in which conductive particles are compressed.

Fig. 6 is a schematic view showing an example of the relationship between the compression load value and the compression displacement when the conductive layer is cracked when the conductive particles are compressed.

1‧‧‧Electrical particles

1a‧‧‧ Protrusion

2‧‧‧Substrate particles

3‧‧‧ Conductive layer

3a‧‧‧ Protrusion

4‧‧‧ core material

5‧‧‧Insulating substances

Claims (14)

An electroconductive particle comprising: a substrate particle and a conductive layer, which is disposed on a surface of the substrate particle, and contains at least one metal component selected from the group consisting of nickel, boron, and tungsten and molybdenum; and is disposed on the substrate On the surface of the particle, on the surface of the outer side of the conductive layer containing nickel, boron, and the metal component, no other conductive layer is disposed; and the conductive layer disposed on the surface of the substrate particle is 100% by weight of the whole The content of the above metal component is 0.01% by weight or more and 40% by weight or less. The conductive particles according to claim 1, wherein the content of the boron in the total 100% by weight of the conductive layer disposed on the surface of the substrate particles is 0.05% by weight or more and 4% by weight or less. The conductive particles according to claim 1 or 2, wherein the content of the metal component in the total 100% by weight of the conductive layer disposed on the surface of the substrate particle is 0.1% by weight or more and 30% by weight or less. The conductive particles according to claim 1 or 2, wherein the content of the metal component in the total 100% by weight of the conductive layer disposed on the surface of the substrate particle is more than 5% by weight and not more than 30% by weight. The conductive particle of claim 1 or 2, wherein the metal component contains tungsten. The conductive particles according to claim 1 or 2 have a compression elastic modulus of 10 N/cm ² or more and 15,000 N/mm ² or less when the compression deformation is 10%. The conductive particles according to claim 1 or 2 have a compression recovery ratio of 5% or more and 70% or less. The electroconductive particle of claim 1 or 2, wherein the metal component contains molybdenum. The conductive particles according to claim 1 or 2, wherein the conductive layer disposed on the surface of the substrate particle contains nickel and molybdenum, and is disposed on 100% by weight of the entire conductive layer on the surface of the substrate particle. The content of nickel is 70% by weight or more and 99.9% by weight or less, and the content of molybdenum is 0.1% by weight or more and 30% by weight or less. The conductive particles according to claim 1 have a compression elastic modulus of 7,000 N/mm ² or more at 5% compression, and compressively conductive in a range of more than 10% and 25% or less of the particle diameter of the conductive particles before compression in the compression direction. In the case of the particles, the conductive layer disposed on the surface of the substrate particles generates cracks. The conductive particles according to claim 1, 2 or 10, wherein the conductive layer disposed on the surface of the substrate particle has a thickness of 0.05 μm or more and 0.5 μm or less. The conductive particles of claim 1, 2 or 10, wherein the conductive layer disposed on a surface of the substrate particle has a protrusion on an outer surface. A conductive material comprising the conductive particles according to any one of claims 1 to 12, and a binder resin; wherein the content of the binder resin is 10% by weight or more and 99.99% by weight based on 100% by weight of the conductive material; the following. A connection structure including a first connection object member and a second connection pair The image member and the connection portion connecting the first and second connection target members, wherein the connection portion is formed by the conductive particles according to any one of claims 1 to 12, or by containing the conductive particles and bonding Formed by a conductive material of the resin.