Substrate particles, conductive particles, conductive materials, and connecting structures

Abstract

Provided are substrate particles with which the connection resistance of an obtainable connection structure can be reduced and the conduction reliability can be enhanced even when mounted at low pressure.　Substrate particles according to the present invention comprise polyorganosiloxane, wherein: the ratio of the number of silicon atoms having a two-bridge structure in the polyorganosiloxane to the number of silicon atoms having a three-bridge structure is 0.3 to 1.5; and the substrate particles have a compressive elastic modulus of 10,000 N / mm2 to 30,000 N / mm2 when the substrate particles are 10% compressed at 20 °C.

Description

Technical Field

[0001] The present invention relates to base material particles containing polyorganosiloxane. The present invention also relates to conductive particles using the above base material particles, a conductive material, and a connection structure.

Background Art

[0002] Anisotropic conductive materials such as anisotropic conductive paste and anisotropic conductive film are widely known. In the above anisotropic conductive material, conductive particles are dispersed in a binder resin.

[0003] The above anisotropic conductive material is used for electrically connecting electrodes of various connection target members such as flexible printed circuits (FPC), glass substrates, glass epoxy substrates, and semiconductor chips to obtain a connection structure. In addition, as the above conductive particles, conductive particles including base material particles and a conductive layer arranged on the surface of the base material particles may be used. The above conductive particles are pressed into the electrodes of the connection target member during mounting, and recesses (indentations) are formed on the surfaces of the electrodes, whereby good electrical connection between the electrodes can be achieved.

[0004] As an example of base material particles used for the above conductive particles, Patent Document 1 below discloses conductive fine particles including resin particles and at least one conductive metal layer formed on the surface of the resin particles. In the conductive fine particles, the number-average particle diameter of the above resin particles is 8 µm to 50 µm, and the compressive elastic modulus when the diameter of the above resin particles is displaced by 10% is 100 N / mm 2 to 3000 N / mm 2 . In addition, in the conductive fine particles, when A is the recovery rate (%) when the above resin particles are compressed until the diameter is displaced by 10%, and B is the recovery rate (%) when the above resin particles are compressed until the diameter is displaced by 20%, the value of A-B is 35% or more.

[0005] Patent Document 2 below discloses conductive particles in which a conductive layer is formed on the surface of core particles, wherein the maximum value of compression hardness of the above conductive particles is 24000 N / mm 2The above conditions are met, and the compressive hardness is highest at a compressibility of less than 5%, with an average compressive hardness of 5000 N / mm² between 20% and 50% of the compressibility. 2 ~18000N / mm 2 Conductive particles are disclosed, wherein the ratio of the maximum compressive hardness to the average compressive hardness at a compressibility of 20% to 50% is 1.5 to 10. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2014-127464 [Patent Document 2] WO2021 / 095803A1 [Overview of the project] [Problems that the invention aims to solve]

[0007] In recent years, with the increasing flexibility of the components being connected, there has been a growing demand for lower pressure mounting during the manufacturing of connection structures.

[0008] In conductive particles using the substrate particles described in Patent Document 1, because they are flexible, especially when mounted at low pressure, it is difficult to sufficiently form recesses (indentations) on the electrode surface, which can result in high initial connection resistance and low conductivity reliability of the resulting connection structure.

[0009] Furthermore, in the conductive particles described in Patent Document 2, the entire particle is rigid, making it difficult for the conductive particles to deform. In particular, when mounted at low pressure, the contact area between the conductive particles and the electrode becomes small, which can lead to a higher initial connection resistance and lower conductivity reliability of the resulting connection structure.

[0010] The object of the present invention is to provide base particles that can reduce the connection resistance of the resulting connection structure and improve conductivity reliability, even when implemented at low voltage. Furthermore, the present invention also aims to provide conductive particles, conductive materials, and connection structures using the above-mentioned base particles. [Means for solving the problem]

[0011] According to a broader aspect of the present invention, the present invention provides a base particle containing a polyorganosiloxane, wherein the ratio of the number of silicon atoms having a 2-bridged structure to the number of silicon atoms having a 3-bridged structure in the polyorganosiloxane is 0.3 or more and 1.5 or less, and the compressive modulus when compressed by 10% at 20°C is 10,000 N / mm². 2 More than 30000N / mm 2 The following base particles are provided.

[0012] In a specific surface of the substrate particles according to the present invention, the ratio of the load value when compressed by 30% at 20°C to the load value when compressed by 10% at 20°C is 4.0 or less, and the fracture strain is 10% or more and 40% or less.

[0013] In a specific aspect of the substrate particles according to the present invention, the ratio of the absolute value of the difference between the compressive modulus when compressed by 10% at 20°C and the compressive modulus when compressed by 20% at 20°C to the absolute value of the difference between the compressive modulus when compressed by 20% at 20°C and the compressive modulus when compressed by 30% at 20°C is 1.0 or greater.

[0014] In a specific aspect of the substrate particles according to the present invention, the ratio of the absolute value of the difference between the compressive modulus when compressed by 10% at 20°C and the compressive modulus when compressed by 20% at 20°C to the absolute value of the difference between the compressive modulus when compressed by 20% at 20°C and the compressive modulus when compressed by 30% at 20°C is 1.0 or more and 10.0 or less.

[0015] In a specific plane of the substrate particles according to the present invention, the ratio of the compressive modulus when compressed by 20% at 150°C to the compressive modulus when compressed by 20% at 20°C is 0.40 or higher.

[0016] In a specific plane of the base particle according to the present invention, the compression recovery rate when compressed by 20% at 20°C is 60% or more, and the ratio of the compression recovery rate when compressed by 20% at 150°C to the compression recovery rate when compressed by 20% at 20°C is 0.30 or more and 0.90 or less.

[0017] In a specific surface of the substrate particles according to the present invention, the particle diameter is 1.0 μm or more and 5.0 μm or less.

[0018] In a particular aspect of the base particle according to the present invention, the polyorganosiloxane material comprises a first alkoxysilane having polymerizable unsaturated groups and a second alkoxysilane not having polymerizable unsaturated groups.

[0019] In a particular aspect of the substrate particles according to the present invention, the substrate particles comprise a core and a shell disposed on the surface of the core, and are therefore core-shell particles.

[0020] In a specific aspect of the substrate particles according to the present invention, the substrate particles have carboxyl groups on their surface, and the contact angle of water with respect to the substrate particles is 10° or more and 90° or less.

[0021] In a particular aspect of the substrate particles according to the present invention, the substrate particles are used to obtain conductive particles having a conductive layer formed on the surface of the substrate particles.

[0022] According to a broad aspect of the present invention, conductive particles are provided, comprising the above-described base particles and a conductive layer disposed on the surface of the base particles.

[0023] In a particular aspect of the conductive particles according to the present invention, the conductive particles comprise an insulating material disposed on the outer surface of the conductive layer.

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

[0025] According to a broad aspect of the present invention, there is provided a conductive material comprising conductive particles and a binder resin, wherein the conductive particles comprise the above-described base material particles and a conductive layer disposed on a surface of the base material particles.

[0026] According to a broad aspect of the present invention, there is provided a connection structure comprising: a first connection target member having a first electrode on a surface thereof; a second connection target member having a second electrode on a surface thereof; and a connection portion connecting the first connection target member and the second connection target member, wherein a material of the connection portion comprises conductive particles, the conductive particles comprise the above-described base material particles and a conductive layer disposed on a surface of the base material particles, and the first electrode and the second electrode are electrically connected by the conductive particles. Effects of the Invention

[0027] The base material particles according to the present invention are base material particles containing polyorganosiloxane, wherein a ratio of the number of silicon atoms having a two-crosslinked structure to the number of silicon atoms having a three-crosslinked structure in the polyorganosiloxane is 0.3 or more and 1.5 or less, and a compressive elastic modulus when compressed by 10% at 20°C is 10000 N / mm 2 or more and 30000 N / mm 2 or less. Since the base material particles according to the present invention have the above configuration, even when mounted at low pressure, the connection resistance of the obtained connection structure can be lowered, and conduction reliability can be improved. Brief Description of the Drawings

[0028] [Figure 1] Fig. 1 is a cross-sectional view schematically showing base material particles according to a first embodiment of the present invention. [Figure 2] Fig. 2 is a cross-sectional view showing conductive particles using the base material particles according to the first embodiment of the present invention. [Figure 3] Fig. 3 is a cross-sectional view showing a modified example of conductive particles using the base material particles according to the first embodiment of the present invention. [Figure 4]Figure 4 is a schematic front cross-sectional view showing the connection structure using conductive particles as shown in Figure 2. [Modes for carrying out the invention]

[0029] The present invention will be described in detail below.

[0030] (base material particles) The base particles according to the present invention are base particles containing polyorganosiloxane. In the base particles according to the present invention, the ratio of the number of silicon atoms having a 2-bridged structure to the number of silicon atoms having a 3-bridged structure in the polyorganosiloxane is 0.3 or more and 1.5 or less. In the base particles according to the present invention, the compressive modulus when compressed by 10% at 20°C is 10,000 N / mm². 2 More than 30000N / mm 2 The following applies:

[0031] Because the base particles according to the present invention have the above configuration, even when mounted at low pressure, recesses (indentations) are well formed on the surface of the electrodes of the resulting connection structure, and the contact area between the conductive particles and the electrodes can be increased. As a result, the connection resistance of the resulting connection structure can be lowered, and the conductivity reliability can be improved.

[0032] Generally, polyorganosiloxanes have a cross-linked structure. In polyorganosiloxanes, silicon atoms and oxygen atoms adjacent to the silicon atoms form siloxane bonds, and oxygen atoms are shared between silicon atoms in adjacent structural units. In the present invention, the oxygen atoms shared between silicon atoms are referred to as "O 1 / 2 It is expressed as ".

[0033] In this invention, a silicon atom having a single-bridged structure refers to a silicon atom to which one -O-Si group is bonded. That is, a silicon atom having a single-bridged structure refers to a silicon atom to which O is bonded. 1 / 2 The number is 1 (Si-O 1 / 2This represents a silicon atom having the structure represented by -. A silicon atom having a 2-bridge structure refers to a silicon atom in which two -O-Si groups are bonded. In other words, a silicon atom having a 2-bridge structure is one in which O bonded to silicon 1 / 2 The number is 2 (Si-O 2 / 2 This represents a silicon atom having the structure represented by -. A silicon atom having a 3-bridge structure refers to a silicon atom in which three -O-Si groups are bonded. In other words, a silicon atom having a 3-bridge structure is a silicon atom bonded to silicon. 1 / 2 The number is 3 (Si-O 3 / 2 This represents a silicon atom having the structure represented by -. A silicon atom having a 4-bridge structure refers to a silicon atom in which four -O-Si groups are bonded. In other words, a silicon atom having a 4-bridge structure is a silicon atom bonded to silicon. 1 / 2 The number is 4 (Si-O 4 / 2 This represents a silicon atom having the structure shown by -.

[0034] In the above-mentioned substrate particles, the polyorganosiloxane contains silicon atoms having a 2-crosslink structure and silicon atoms having a 3-crosslink structure. The polyorganosiloxane may or may not contain silicon atoms having a 1-crosslink structure. The polyorganosiloxane may or may not contain silicon atoms having a 4-crosslink structure.

[0035] In the above-mentioned base material particles, the ratio of the number of silicon atoms having a 2-bridged structure to the number of silicon atoms having a 3-bridged structure in the polyorganosiloxane is preferably 0.4 or more, more preferably 0.5 or more, even more preferably 0.7 or more, preferably 1.4 or less, more preferably 1.35 or less, and even more preferably 1.3 or less. When the above ratio (number of silicon atoms having a 2-bridged structure / number of silicon atoms having a 3-bridged structure) in the polyorganosiloxane is above the lower limit, recesses (indentations) can be formed more effectively on the surface of the electrodes of the resulting connection structure even when mounted at low pressure. When the above ratio (number of silicon atoms having a 2-bridged structure / number of silicon atoms having a 3-bridged structure) in the polyorganosiloxane is below the upper limit, the contact area between the conductive particles and the electrodes can be increased even when mounted at low pressure.

[0036] In the above-mentioned base material particles, the total number of silicon atoms having a 2-bridged structure and silicon atoms having a 3-bridged structure, out of 100% of the silicon atoms in the polyorganosiloxane, is preferably 1% or more, more preferably 5% or more, even more preferably 10% or more, preferably 99% or less, more preferably 95% or less, and even more preferably 90% or less. When the total number of silicon atoms having a 2-bridged structure and silicon atoms having a 3-bridged structure is above the lower limit and below the upper limit, the effects of the present invention can be exhibited even more effectively.

[0037] The proportions of silicon atoms having 1-bridged structures, 2-bridged structures, 3-bridged structures, and 4-bridged structures in the above polyorganosiloxane can be measured as follows.

[0038] The above substrate particles were analyzed using an NMR spectral analyzer to determine the solid state. 29Si-NMR (measurement frequency: 79.4254 MHz, pulse width: 3.7 μs, sample holder: 8 mm, sample rotation speed: 7 kHz, number of integrations: 3600, measurement temperature: 25 °C) will be performed. From the obtained results, the Si-O of polyorganosiloxane in the substrate particles will be investigated. 1 / 2 - A structure represented by Si-O 2 / 2 - A structure represented by Si-O 3 / 2 - A structure represented by - and Si-O 4 / 2 The proportion of each peak area of ​​the structure represented by - is calculated. The obtained proportion of each peak area is taken as the proportion of the number of silicon atoms with 1-bridged structures, 2-bridged structures, 3-bridged structures, and 4-bridged structures in the polyorganosiloxane described above. Examples of NMR spectral analyzers include the JEOL "ECX400".

[0039] The above polyorganosiloxane can be obtained by hydrolysis and condensation of an alkoxysilane, or by hydrolysis and condensation of a chlorosilane, etc. From the viewpoint of controlling the reaction, it is preferable to obtain the above polyorganosiloxane by hydrolysis and condensation of an alkoxysilane. An alkoxysilane is a silane compound having an alkoxy group.

[0040] Examples of the above-mentioned alkoxysilanes include methyltrimethoxysilane, vinyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, dimethoxydiphenylsilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, 1,6-bis(trimethoxysilyl)hexane, and 3,3,3-trifluoropropyltrimethoxysilane. The above-mentioned alkoxysilanes may be used individually or in combination of two or more.

[0041] From the viewpoint of suppressing fracture strain, it is preferable that the polyorganosiloxane material contains a first alkoxysilane having polymerizable unsaturated groups and a second alkoxysilane not having polymerizable unsaturated groups.

[0042] The first alkoxysilane described above has a polymerizable unsaturated group. The polymerizable unsaturated group in the first alkoxysilane may be one, two, three, or four. In the first alkoxysilane, a group different from the alkoxy group may be the polymerizable unsaturated group. If the first alkoxysilane has multiple polymerizable unsaturated groups, each polymerizable unsaturated group may be the same or different.

[0043] From the viewpoint of suppressing fracture strain, the number of carbon atoms in the polymerizable unsaturated group in the first alkoxysilane is preferably 1 or more, more preferably 2 or more, even more preferably 3 or more, preferably 10 or less, more preferably 9 or less, and even more preferably 8 or less. From the viewpoint of suppressing fracture strain, the polymerizable unsaturated group in the first alkoxysilane is preferably a vinyl group or a propylene group, and more preferably a vinyl group.

[0044] Examples of the first alkoxysilane mentioned above include vinyltrimethoxysilane. From the viewpoint of increasing the reactivity between the first alkoxysilane and the second alkoxysilane, it is preferable that the first alkoxysilane is vinyltrimethoxysilane.

[0045] The second alkoxysilane described above does not have a polymerizable unsaturated group. The second alkoxysilane preferably has an alkyl group. The alkyl group in the second alkoxysilane may be one, two, or three. If the second alkoxysilane has multiple alkyl groups, each alkyl group may be the same or different.

[0046] From the viewpoint of improving the compressibility of the base particles (especially the compressibility in the initial stages of compression), the number of carbon atoms in the alkyl group in the second alkoxysilane is preferably 1 or more, more preferably 2 or more, even more preferably 3 or more, preferably 10 or less, more preferably 9 or less, and even more preferably 8 or less. From the viewpoint of increasing the reactivity between the first alkoxysilane and the second alkoxysilane, the alkyl group in the second alkoxysilane is preferably an ethyl group or a methyl group, and more preferably a methyl group.

[0047] Examples of the second alkoxysilane mentioned above include tetraethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, methyltriethoxysilane, and methyltrimethoxysilane. From the viewpoint of improving the compressibility of the base material particles (especially the compressibility in the initial stages of compression), the second alkoxysilane is preferably ethyltriethoxysilane or methyltrimethoxysilane, and more preferably methyltrimethoxysilane.

[0048] In 100% by weight of the polyorganosiloxane material, the content of the first alkoxysilane is preferably 30% by weight or more, more preferably 40% by weight or more, even more preferably 50% by weight or more, preferably 90% by weight or less, more preferably 85% by weight or less, and even more preferably 80% by weight or less. When the content of the first alkoxysilane is above the lower limit and below the upper limit, the compression characteristics of the base particles (especially the compression characteristics from the middle to the late stages of compression) can be improved.

[0049] In 100% by weight of the polyorganosiloxane material, the content of the second alkoxysilane is preferably 10% by weight or more, more preferably 20% by weight or more, even more preferably 30% by weight or more, preferably 90% by weight or less, more preferably 80% by weight or less, and even more preferably 70% by weight or less. When the content of the second alkoxysilane is above the lower limit and below the upper limit, the compressibility of the base particles (especially the compressibility in the initial stages of compression) can be improved.

[0050] The content of the polyorganosiloxane in 100% by weight of the above base material particles is preferably 10% by weight or more, more preferably 20% by weight or more, even more preferably 30% by weight or more, preferably 99% by weight or less, more preferably 95% by weight or less, and even more preferably 90% by weight or less. When the content of the polyorganosiloxane is above the lower limit and below the upper limit, the compressibility of the base material particles (especially the compressibility in the initial stage of compression) can be improved.

[0051] The polyorganosiloxane may be a copolymer (reactant) of the first alkoxysilane and the second alkoxysilane, or a composite of a polymer (reactant) of the first alkoxysilane and a polymer (reactant) of the second alkoxysilane.

[0052] From the viewpoint of improving the compressibility of the base material particles, it is preferable that the base material particles comprise a core and a shell disposed on the surface of the core, and are core-shell particles. In the core-shell particles, it is preferable that the material of the core contains the first alkoxysilane and the material of the shell contains the second alkoxysilane. In the core-shell particles, it is preferable that the core is a polymer of the first alkoxysilane and the shell is a polymer of the second alkoxysilane. When the core-shell particles satisfy the above preferred embodiments, the compressibility of the base material particles becomes even more favorable, and the contact area between the conductive particles and the electrodes can be increased even when mounted at low pressure. As a result, the connection resistance of the resulting connection structure can be reduced and the conductivity reliability can be improved.

[0053] The particle size of the core is preferably 0.1 μm or more, more preferably 1.0 μm or more, preferably 5.0 μm or less, more preferably 4.75 μm or less, even more preferably 4.5 μm or less, still more preferably 4.0 μm or less, and particularly preferably 3.75 μm or less. When the particle size of the core is above the lower limit and below the upper limit, the compression characteristics of the base particles can be improved.

[0054] The particle diameter of the core mentioned above refers to the diameter if the core is spherical, and if the core has a shape other than a perfect sphere, it refers to the diameter assuming it is a perfect sphere of a volume equivalent to that shape. Furthermore, the particle diameter of the core refers to the average particle diameter measured by any particle size measuring device. For example, particle size distribution analyzers using principles such as laser light scattering, changes in electrical resistance, and image analysis after imaging can be used.

[0055] The thickness of the above shell is preferably 100 nm or more, more preferably 200 nm or more, more preferably 5.0 μm or less, and more preferably 3.0 μm or less. When the thickness of the above shell is above the lower limit and below the upper limit, the compression characteristics of the substrate particles can be improved.

[0056] The thickness of the shell can be determined from the difference between the average particle diameter of the substrate particles and the particle diameter of the core.

[0057] From the viewpoint of easily forming a conductive layer, as described later, on the surface of the above-mentioned substrate particles, it is preferable that the above-mentioned substrate particles have carboxyl groups on their surface.

[0058] The presence or absence of carboxyl groups on the surface of the above-mentioned substrate particles can be evaluated by FT-IR (infrared spectrophotometer).

[0059] The water contact angle with the substrate particles is preferably 10° or more, more preferably 20° or more, even more preferably 30° or more, preferably 100° or less, more preferably 90° or less, and even more preferably 80° or less. If the water contact angle with the substrate particles is above the lower limit, the conductive layer described later can be easily formed on the surface of the substrate particles. If the water contact angle with the substrate particles is below the upper limit, aggregation of the substrate particles can be suppressed.

[0060] The contact angle of water with respect to the above-mentioned substrate particles is preferably a static contact angle. The static contact angle of water with respect to the above-mentioned substrate particles can be measured as follows.

[0061] Using a contact angle meter, the static contact angle is measured at 20°C by dropping 100 μL of pure water onto substrate particles supported on an adhesive tape. Examples of such contact angle meters include the "Contact Angle Meter PG-X" manufactured by Matsubo Co., Ltd.

[0062] The static contact angle between the substrate particles and water can be controlled by the type of alkoxysilane, the concentration of oxygen during calcination of the substrate particle material, and silane coupling treatment, etc.

[0063] The method for producing the above-mentioned base particle is not particularly limited. Preferably, the base particle is obtained by calcining the material of the base particle.

[0064] The firing temperature is preferably 200°C or higher, more preferably 250°C or higher, even more preferably 350°C or higher, preferably 850°C or lower, more preferably 750°C or lower, and even more preferably 650°C or lower. If the firing temperature is above the lower limit, the compression characteristics of the base material particles can be improved. If the firing temperature is below the upper limit, the fracture resistance of the base material particles can be increased.

[0065] The above-mentioned calcined oxygen concentration is preferably 0% or more, more preferably 1% or more, even more preferably 3% or more, preferably 21% or less, more preferably 20% or less, and even more preferably 15% or less. If the above-mentioned calcined oxygen concentration is above the above lower limit, the compression characteristics of the base material particles (especially the compression characteristics from the middle to the late stages of compression) can be improved. If the above-mentioned calcined oxygen concentration is below the above upper limit, the fracture resistance of the base material particles can be increased.

[0066] The above-mentioned base particles may contain, in addition to the polyorganosiloxane, for example, a base catalyst, an acid catalyst, a surfactant, an inorganic filler, and a particle dispersant.

[0067] Figure 1 is a schematic cross-sectional view showing substrate particles according to the first embodiment of the present invention.

[0068] Base particle 1 contains a polyorganosiloxane. In base particle 1, the ratio of silicon atoms having a 2-bridged structure to silicon atoms having a 3-bridged structure in the polyorganosiloxane is between 0.3 and 1.5. In base particle 1, the compressive modulus when compressed by 10% at 20°C is 10,000 N / mm². 2 More than 30000N / mm 2 The following applies:

[0069] The compressive modulus (10% K value at 20°C) when compressed by 10% at 20°C is preferably 11000 N / mm 2 More preferably, 12000 N / mm 2 More preferably, 14000 N / mm 2 The above is preferable, preferably 29000 N / mm 2 More preferably, 28,000 N / mm 2 More preferably, 25,000 N / mm 2 The following applies: If the 10%K value at 20°C is above the lower limit and below the upper limit, even when mounted at low pressure, recesses (indentations) can be formed more effectively on the electrode surface of the resulting connection structure.

[0070] The compressive modulus (20% K value at 20°C) when compressed by 20% at 20°C is preferably 10500 N / mm². 2 More preferably, 11500 N / mm 2 More preferably, 13500 N / mm 2 The above is preferable, and preferably 28500 N / mm 2 More preferably, 27,500 N / mm 2 More preferably, 24,500 N / mm 2 The following applies: If the 20%K value at 20°C is above the lower limit and below the upper limit, the contact area between the conductive particles and the electrode can be further increased even when implemented at low pressure.

[0071] The compressive modulus (30% K value at 20°C) when compressed by 30% at 20°C is preferably 5000 N / mm². 2 More preferably, 8000 N / mm2 More preferably, 12500 N / mm 2 The above is preferable, and preferably 27500 N / mm 2 More preferably, 26,500 N / mm 2 More preferably, 23,500 N / mm 2 The following applies: If the 30%K value at 20°C is above the lower limit and below the upper limit, the contact area between the conductive particles and the electrode can be further increased even when mounted at low pressure.

[0072] In the above-mentioned base material particles, it is preferable that a higher compressive modulus is exhibited in the initial stage of compression (e.g., at 10% compression) than in the middle stage of compression (e.g., at 20% compression) and the later stage of compression (e.g., at 30% compression). When the above-mentioned base material particles satisfy the above-mentioned preferred embodiment, when electrodes are electrically connected using conductive particles in which a conductive layer is formed on the surface of the base material particles, the rigidity in the initial stage of compression allows for the good formation of recesses (indentations) on the surface of the electrodes, and the flexibility from the middle to the later stage of compression allows for a sufficiently large contact area between the electrodes and the conductive particles. Therefore, the connection resistance between electrodes can be reduced, and the conductivity reliability between electrodes can be improved. For example, even if a connection structure in which electrodes are electrically connected by conductive particles is left for a long time under high temperature and high humidity conditions, the connection resistance is less likely to increase, and connection failures are less likely to occur.

[0073] The ratio of the absolute value of the difference between the 10%K value at 20°C and the 20%K value at 20°C to the absolute value of the difference between the 20%K value at 20°C and the 30%K value at 20°C is defined as the ratio (absolute value of the difference between the 10%K value at 20°C and the 20%K value at 20°C / absolute value of the difference between the 20%K value at 20°C and the 30%K value at 20°C). The above ratio (absolute value of the difference between the 10%K value at 20°C and the 20%K value at 20°C / absolute value of the difference between the 20%K value at 20°C and the 30%K value at 20°C) is preferably between 1.0 and 10.0. The above ratio (absolute value of the difference between the 10%K value at 20°C and the 20%K value at 20°C / absolute value of the difference between the 20%K value at 20°C and the 30%K value at 20°C) is preferably 1.0 or more, more preferably greater than 1.0, even more preferably 2.5 or more, preferably 10.0 or less, more preferably 9.5 or less, and even more preferably 6.0 or less. When the above ratio (absolute value of the difference between the 10%K value at 20°C and the 20%K value at 20°C / absolute value of the difference between the 20%K value at 20°C and the 30%K value at 20°C) is within the above range, the effects of the present invention can be exhibited even more effectively.

[0074] The compressive modulus (20% K value at 150°C) when compressed by 20% at 150°C is preferably 2000 N / mm². 2 More preferably, 3000 N / mm 2 More preferably 5000 N / mm 2 The above is preferable, preferably 25,000 N / mm 2 More preferably, 22,000 N / mm 2 More preferably, 18,000 N / mm 2 The following applies: If the 20%K value at 150°C is above the lower limit and below the upper limit, the resulting connection structure will not easily develop high connection resistance and connection failures will be less likely to occur, even if left for a long time under high temperature and high humidity conditions.

[0075] The ratio of the compressive modulus when compressed by 20% at 150°C to the compressive modulus when compressed by 20% at 20°C is preferably 0.30 or more, more preferably 0.40 or more, even more preferably 0.45 or more, preferably 1.0 or less, more preferably 0.80 or less, and even more preferably 0.70 or less. When the above ratio (20%K value at 150°C / 20%K value at 20°C) is above the lower limit and below the upper limit, the connection resistance is less likely to increase and connection failures are less likely to occur even when the resulting connection structure is left for a long time under high temperature and high humidity conditions.

[0076] The load value when compressed by 10% at 20°C (10% load value at 20°C) is preferably 0.5 mN or more, more preferably 0.7 mN or more, even more preferably 0.9 mN or more, preferably 3.5 mN or less, more preferably 3.0 mN or less, and even more preferably 2.5 mN or less. When the above 10% load value at 20°C is above the lower limit and below the upper limit, even when mounted at low pressure, recesses (indentations) can be formed more effectively on the electrode surface of the resulting connection structure.

[0077] The load value when compressed by 20% at 20°C (20% load value at 20°C) is preferably 0.9 mN or more, more preferably 1.2 mN or more, even more preferably 1.5 mN or more, preferably 8.0 mN or less, more preferably 6.5 mN or less, and even more preferably 5.5 mN or less. When the above 20% load value at 20°C is above the lower limit and below the upper limit, the contact area between the conductive particles and the electrodes can be further increased even when mounted at low pressure.

[0078] The load value when compressed by 30% at 20°C (30% load value at 20°C) is preferably 2.0 mN or more, more preferably 2.3 mN or more, even more preferably 2.7 mN or more, preferably 11 mN or less, more preferably 9.0 mN or less, and even more preferably 7.0 mN or less. If the above 30% load value at 20°C is above the lower limit and below the upper limit, springback after compression can be prevented.

[0079] The ratio of the load value when compressed by 30% at 20°C to the load value when compressed by 10% at 20°C is preferably 1.0 or more, more preferably 2.0 or more, even more preferably 2.5 or more, preferably 4.0 or less, more preferably 3.5 or less, and even more preferably 3.0 or less. When the above ratio (30% load value at 20°C / 10% load value at 20°C) is above the lower limit and below the upper limit, springback after compression can be prevented.

[0080] The compressive modulus of the above-mentioned base material particles at 20°C (10%K value, 20%K value, and 30%K value), and the load values ​​of the above-mentioned base material particles at 20°C (10% load value, 20% load value, and 30% load value) can be measured as follows.

[0081] Using a microcompression testing machine, the substrate particles are compressed with a smooth diamond indenter end face of a cylinder (100 μm in diameter) under the conditions of 20°C, a compression speed of 0.3 mN / sec, and a maximum test load of 20 mN. The load value (N) and compression displacement (mm) are measured at this time. From the obtained measurements, the compressive modulus can be determined by the following formula. As the microcompression testing machine, for example, the Fischerscope H-100 manufactured by Fischer GmbH is used.

[0082] 10%K value, 20%K value, or 30%K value (N / mm²) at 20°C 2 )=(3 / 2 1 / 2 )·F·S -3 / 2 ·R -1 / 2 F: Load value (N) when the base material particles are compressed and deformed by 10%, 20%, or 30%. S: Compressive displacement (mm) when the base material particles are compressed by 10%, 20%, or 30%. R: Radius of the base particle (mm)

[0083] The compressive modulus (20%K value) of the above-mentioned substrate particles at 150°C can be measured as follows.

[0084] Using a microcompression testing machine, the substrate particles are compressed with a smooth diamond indenter end face (100 μm in diameter) at 150°C, a compression speed of 0.3 mN / sec, and a maximum test load of 20 mN. The load value (N) and compression displacement (mm) are measured at this time. From the obtained measurements, the compressive modulus can be determined by the following formula. As the microcompression testing machine, for example, the Fischerscope H-100 manufactured by Fischer GmbH is used.

[0085] 20% K value at 150℃ (N / mm 2 )=(3 / 2 1 / 2 )·F·S -3 / 2 ·R -1 / 2 F: Load value (N) when the base material particles are compressed and deformed by 20%. S: Compression displacement (mm) when the base material particles are compressed by 20%. R: Radius of the base particle (mm)

[0086] The compression recovery rate when compressed by 20% at 20°C (20% compression recovery rate at 20°C) is preferably 40% or more, more preferably 50% or more, even more preferably 60% or more, and particularly preferably 70% or more. When the 20% compression recovery rate at 20°C is above the lower limit, the conductive particles can easily deform in response to fluctuations in the spacing between electrodes. As a result, connection failures between electrodes become less likely to occur. The 20% compression recovery rate at 20°C is preferably less than 100%.

[0087] The compression recovery rate when compressed by 20% at 150°C (20% compression recovery rate at 150°C) is preferably 10% or more, more preferably 20% or more, even more preferably 30% or more, and particularly preferably 40% or more. When the 20% compression recovery rate at 150°C is above the lower limit, the conductive particles can easily deform in response to fluctuations in the spacing between electrodes. As a result, connection failures between electrodes become less likely to occur. The 20% compression recovery rate at 150°C is preferably less than 100%.

[0088] The ratio of the compression recovery rate when compressed by 20% at 150°C to the compression recovery rate when compressed by 20% at 20°C is preferably 0.30 or higher, more preferably 0.40 or higher, preferably 0.90 or lower, and more preferably 0.80 or lower. When the above ratio (20% compression recovery rate at 150°C / 20% compression recovery rate at 20°C) is above the lower limit and below the upper limit, the usable temperature range of the base particles can be broadened.

[0089] The 20% compression recovery rate of the above-mentioned substrate particles at 20°C and at 150°C can be measured as follows.

[0090] The substrate particles are scattered on the sample stage. For each scattered substrate particle, a microcompression tester is used to apply a load (reverse load value) towards the center of the substrate particle at 20°C or 150°C using the smooth end face of a cylindrical (100 μm diameter, diamond) indenter until the substrate particle is compressed by 20%. Then, the load is removed until it returns to the origin load value (0.40 mN). The load-compression displacement during this time is measured, and the compression recovery rate can be calculated using the following formula. The loading speed is set to 0.33 mN / sec. As the microcompression tester, for example, the Fischerscope H-100 manufactured by Fischer GmbH can be used.

[0091] Compression recovery rate (%) = [L2 / L1] × 100 L1: Compressive displacement from the origin load value to the reverse load value when a load is applied. L2: Unloading displacement from the reversal load value when the load is released to the origin load value.

[0092] The fracture strain of the above-mentioned base material particles is preferably 10% or more, more preferably 20% or more, preferably 40% or less, and more preferably 35% or less. If the fracture strain is above the lower limit, when used in a conductive material or connecting structure, the excludability of the binder resin and the penetration of the oxide film of the conductive layer and electrode become higher, and the connection resistance becomes even lower. If the fracture strain is below the upper limit, the flexibility in the middle of compression increases the contact area between the conductive particles and the electrode, and the connection resistance becomes even lower.

[0093] In the above-mentioned substrate particles, when evaluating the compression behavior of the substrate particles, a point is observed where the displacement changes significantly at a certain load value. The load value at this point of change is the fracture load value, and the displacement is the fracture displacement. The ratio of this fracture displacement to the particle diameter before compression (fracture displacement / particle diameter before compression) × 100 is defined as fracture strain (%). For example, if a particle with a particle diameter of 5 μm before compression exhibits fracture behavior at a displacement of 1 μm, the fracture strain is calculated to be 20%. In the case of core-shell particles, the fracture behavior of the shell is generally observed in the initial stages of displacement.

[0094] The fracture strain described above can be evaluated from the measurement of the compressive modulus, and can be measured by reading the displacement at the discontinuity point of the compressive displacement curve. It is preferable to measure the fracture strain at 20°C.

[0095] The particle size of the above-mentioned base material particles is preferably 0.1 μm or more, more preferably 1.0 μm or more, preferably 500 μm or less, more preferably 100 μm or less, even more preferably 50 μm or less, even more preferably 10 μm or less, and particularly preferably 5.0 μm or less. When the particle size of the above-mentioned base material particles is above the lower limit, the contact area between the conductive particles and the electrodes becomes larger, which can further improve the conductivity reliability between electrodes and further reduce the connection resistance between electrodes connected via the conductive particles. Furthermore, when forming the conductive portion on the surface of the base material particles by electroless plating, it becomes difficult for aggregated conductive particles to form. When the particle size of the above-mentioned base material particles is below the upper limit, the conductive particles are easily compressed, which can further reduce the connection resistance between electrodes and further reduce the distance between electrodes.

[0096] The particle diameter of the above-mentioned base material particles is preferably the average particle diameter, and more preferably the number-average particle diameter. The particle diameter of the above-mentioned base material particles can be determined by observing 50 arbitrary base material particles with an electron microscope or optical microscope and calculating the average value of the particle diameter of each base material particle, or by using a particle size distribution analyzer. In observation with an electron microscope or optical microscope, the particle diameter of one base material particle is determined as the particle diameter at the equivalent diameter of a circle. In observation with an electron microscope or optical microscope, the average particle diameter at the equivalent diameter of a circle of any 50 base material particles is approximately equal to the average particle diameter at the equivalent diameter of a sphere. In a particle size distribution analyzer, the particle diameter of one base material particle is determined as the particle diameter at the equivalent diameter of a sphere. It is preferable to calculate the average particle diameter of the above-mentioned base material particles using a particle size distribution analyzer. When measuring the particle diameter of the above-mentioned base material particles in the case of conductive particles, it can be measured, for example, as follows.

[0097] A resin body for conductive particle inspection is prepared by adding conductive particles to Kulzer's "Technovit 4000" so that the conductive particle content is 30% by weight, and then dispersing them. A cross-section of the conductive particles is cut out using an ion milling device (Hitachi High-Technologies Corporation's "IM4000") so as to pass through the vicinity of the center of the substrate particles dispersed in the above-mentioned resin body. Then, using a field emission scanning electron microscope (FE-SEM) with the image magnification set to 25,000x, 50 conductive particles are randomly selected, and the substrate particles of each conductive particle are observed. The particle diameter of the substrate particles in each conductive particle is measured, and these are arithmetic mean to obtain the particle diameter of the substrate particles.

[0098] The aspect ratio of the above-mentioned base material particles is preferably 2.0 or less, more preferably 1.5 or less, and even more preferably 1.2 or less. The above aspect ratio represents the ratio of the major axis to the minor axis.

[0099] The applications of the above-mentioned base material particles are not particularly limited. The above-mentioned base material particles can be suitably used in a variety of applications. Preferably, the above-mentioned base material particles are used to obtain conductive particles having the conductive layer formed on the surface of the base material particles. That is, it is preferable that the above-mentioned base material particles are base material particles for conductive particles. Since the above-mentioned base material particles have good compressive deformation characteristics and compressive fracture characteristics, when a conductive layer is formed on the surface of the above-mentioned base material particles and they are used as conductive particles to electrically connect electrodes, the conductive particles are efficiently arranged between substrates or between electrodes. Furthermore, with the above-mentioned base material particles, connection failures and display failures are less likely to occur in connection structures using the above-mentioned conductive particles.

[0100] (Conductive particles) The conductive particles described above comprise the aforementioned base material particles and a conductive layer disposed on the surface of the base material particles. Because the conductive particles have the above configuration, even when mounted at low pressure, the connection resistance of the resulting connection structure can be reduced and the conductivity reliability can be improved.

[0101] Figure 2 is a cross-sectional view showing conductive particles using substrate particles according to the first embodiment of the present invention.

[0102] The conductive particle 11 shown in Figure 2 comprises a base particle 1 and a conductive layer 2 disposed on the surface of the base particle 1. The conductive layer 2 covers the surface of the base particle 1. The conductive particle 11 is a coated particle in which the surface of the base particle 1 is covered by the conductive layer 2.

[0103] Figure 3 is a cross-sectional view showing a modified example of conductive particles using substrate particles according to the first embodiment of the present invention.

[0104] The conductive particles 21 shown in Figure 3 consist of a base particle 1, a conductive layer 22, a plurality of core materials 23, and a plurality of insulating materials 24.

[0105] The conductive layer 22 is arranged on the surface of the base particle 1. The conductive particle 21 has a plurality of protrusions 21a on its surface. The conductive layer 22 has a plurality of protrusions 22a on its outer surface. Thus, the conductive particles may have protrusions on their surface, or the conductive layer may have protrusions on its outer surface. A plurality of core materials 23 are arranged on the surface of the base particle 1. The plurality of core materials 23 are embedded in the conductive layer 22. The core materials 23 are arranged inside the protrusions 21a and 22a. The conductive layer 22 covers the plurality of core materials 23. The outer surface of the conductive layer 22 is raised by the plurality of core materials 23, forming the protrusions 21a and 22a.

[0106] The conductive particles 21 have an insulating material 24 disposed on the outer surface of the conductive layer 22. At least a portion of the outer surface of the conductive layer 22 is covered with the insulating material 24. The insulating material 24 is made of an insulating material and is an insulating particle. Thus, the conductive particles may have an insulating material disposed on the outer surface of the conductive layer.

[0107] The metal used to form the conductive layer described above is not particularly limited. Examples of such metals include gold, silver, palladium, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, thallium, germanium, cadmium, silicon, tungsten, molybdenum, and alloys thereof. Other examples of such metals include tin-doped indium oxide (ITO) and solder. Alloys containing tin, nickel, palladium, copper, or gold are preferred, with nickel or palladium being preferred, as they can further reduce the connection resistance between electrodes.

[0108] The conductive layer may be formed by a single layer, as in the case of conductive particles 11 and 21. The conductive layer may be formed by multiple layers. That is, the conductive layer may have a laminated structure of two or more layers. When the conductive layer is formed by multiple layers, the outermost layer is preferably a gold layer, a nickel layer, a palladium layer, a copper layer, or an alloy layer containing tin and silver, and more preferably a gold layer. When the outermost layer is one of these preferred conductive layers, the connection resistance between electrodes becomes even lower. Furthermore, when the outermost layer is a gold layer, the corrosion resistance becomes even higher.

[0109] The method for forming a conductive layer on the surface of the substrate particles is not particularly limited. Examples of methods for forming a conductive layer include electroless plating, electroplating, physical vapor deposition, and coating the surface of the substrate particles with metal powder or a paste containing metal powder and a binder. Electroless plating is preferred because it allows for easy formation of the conductive layer. Examples of physical vapor deposition methods include vacuum deposition, ion plating, and ion sputtering.

[0110] The compressive modulus (10% K value of the conductive particles at 20°C) when the above conductive particles are compressed by 10% at 20°C is preferably 12000 N / mm 2 More preferably, 17,000 N / mm 2 More preferably, 23,000 N / mm 2 The above is preferable, with a load of 37,000 N / mm². 2 More preferably, 34,000 N / mm 2 More preferably, 31,000 N / mm 2 The following applies: If the 10%K value of the conductive particles at 20°C is above the lower limit and below the upper limit, then even when mounted at low pressure, recesses (indentations) can be formed more effectively on the electrode surface of the resulting connection structure.

[0111] The compressive modulus (20% K value of the conductive particles at 20°C) when the above conductive particles are compressed by 20% at 20°C is preferably 8000 N / mm². 2More preferably, 10,000 N / mm 2 More preferably, 13,000 N / mm 2 The above is preferable, and preferably 28500 N / mm 2 More preferably, 27,500 N / mm 2 More preferably, 24,500 N / mm 2 The following applies: If the 20%K value of the conductive particles at 20°C is above the lower limit and below the upper limit, the contact area between the conductive particles and the electrode can be further increased even when mounted at low pressure.

[0112] The compressive modulus (30% K value of the conductive particles at 20°C) when the above conductive particles are compressed by 30% at 20°C is preferably 5500 N / mm². 2 More preferably, 8000 N / mm 2 More preferably, 10,000 N / mm 2 The above is preferable, and preferably 27500 N / mm 2 More preferably, 26,500 N / mm 2 More preferably, 23,500 N / mm 2 The following applies: If the 30%K value of the conductive particles at 20°C is above the lower limit and below the upper limit, the contact area between the conductive particles and the electrode can be further increased even when mounted at low pressure.

[0113] In the above-mentioned conductive particles, it is preferable that a higher compressive modulus is exhibited in the initial stage of compression (e.g., at 10% compression) than in the middle stage of compression (e.g., at 20% compression) and the later stage of compression (e.g., at 30% compression). When the above-mentioned base particles satisfy the above-mentioned preferred embodiment, when electrodes are electrically connected using the conductive particles, the rigidity in the initial stage of compression allows for the good formation of recesses (indentations) on the electrode surface, and the flexibility from the middle to the later stage of compression allows for a sufficiently large contact area between the electrode and the conductive particles. Therefore, the connection resistance between electrodes can be reduced, and the conductivity reliability between electrodes can be improved. For example, even if a connection structure in which electrodes are electrically connected by conductive particles is left for a long time under high temperature and high humidity conditions, the connection resistance is less likely to increase, and connection failures are less likely to occur.

[0114] The ratio of the absolute value of the difference between the 10%K value of the conductive particles at 20°C and the 20%K value of the conductive particles at 20°C to the absolute value of the difference between the 20%K value of the conductive particles at 20°C and the 30%K value of the conductive particles at 20°C is defined as the ratio (absolute value of the difference between the 10%K value at 20°C and the 20%K value at 20°C / absolute value of the difference between the 20%K value at 20°C and the 30%K value at 20°C). The above ratio (absolute value of the difference between the 10%K value at 20°C and the 20%K value at 20°C / absolute value of the difference between the 20%K value at 20°C and the 30%K value at 20°C) is preferably 1.0 or more, more preferably greater than 1.0, even more preferably 2.5 or more, preferably 10.0 or less, more preferably 9.5 or less, and even more preferably 6.0 or less. If the above ratio (absolute value of the difference between the 10%K value at 20°C and the 20%K value at 20°C / absolute value of the difference between the 20%K value at 20°C and the 30%K value at 20°C) is within the above range, the effects of the present invention can be exhibited even more effectively.

[0115] The compressive moduli (10%K, 20%K, and 30%K values) of the above conductive particles at 20°C can be measured as follows.

[0116] Using a microcompression testing machine, conductive particles are compressed on the smooth end face of a cylindrical (100 μm diameter, diamond) indenter under the conditions of 20°C, a compression speed of 0.3 mN / sec, and a maximum test load of 20 mN. The load value (N) and compression displacement (mm) are measured at this time. From the obtained measurements, the compressive modulus can be determined by the following formula. As the microcompression testing machine, for example, the Fischerscope H-100 manufactured by Fischer GmbH is used.

[0117] The 10%K, 20%K, or 30%K values ​​(N / mm²) of conductive particles at 20°C. 2 )=(3 / 2 1 / 2 )·F·S -3 / 2 ·R -1 / 2 F: Load value (N) when conductive particles are compressed and deformed by 10%, 20%, or 30%. S: Compressive displacement (mm) when conductive particles are compressed by 10%, 20%, or 30%. R: Radius of conductive particle (mm)

[0118] The particle size of the conductive particles is preferably 0.5 μm or more, more preferably 1.0 μm or more, preferably 500 μm or less, more preferably 100 μm or less, even more preferably 50 μm or less, and particularly preferably 20 μm or less. When the particle size of the conductive particles is above the lower limit and below the upper limit, when electrodes are connected using the conductive particles, the contact area between the conductive particles and the electrodes becomes sufficiently large, and aggregated conductive particles are less likely to form when forming the conductive layer. In addition, the gap between electrodes connected via the conductive particles does not become too large, and the conductive layer is less likely to peel off from the surface of the substrate particles. Furthermore, when the particle size of the conductive particles is above the lower limit and below the upper limit, the conductive particles can be suitably used in applications as conductive materials.

[0119] The thickness of the conductive layer is preferably 0.005 μm or more, more preferably 0.01 μm or more, more preferably 10 μm or less, more preferably 1.0 μm or less, and even more preferably 0.3 μm or less. The thickness of the conductive layer is the total thickness of the conductive layer if the conductive layer is multilayered. When the thickness of the conductive layer is above the lower limit and below the upper limit, sufficient conductivity is obtained, and the conductive particles do not become too hard, and the conductive particles deform sufficiently when connecting electrodes.

[0120] When the conductive layer is formed by multiple layers, the thickness of the outermost conductive layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, preferably 0.50 μm or less, and more preferably 0.10 μm or less. When the thickness of the outermost conductive layer is above the lower limit and below the upper limit, the coating by the outermost conductive layer becomes uniform, corrosion resistance becomes sufficiently high, and the connection resistance between electrodes becomes even lower. Also, when the outermost layer is a gold layer, the thinner the gold layer, the lower the cost.

[0121] The thickness of the conductive layer can be measured, for example, by observing the cross-section of the conductive particles using a transmission electron microscope (TEM).

[0122] The conductive particles may have protrusions on their surface. The conductive particles may also have protrusions on the outer surface of the conductive layer. It is preferable that there are multiple protrusions. Often, an oxide film is formed on the surface of the conductive layer and on the surface of the electrodes connected by the conductive particles. When conductive particles with protrusions are used, the oxide film is effectively removed by the protrusions when the conductive particles are placed between the electrodes and pressed together. This makes it possible to make contact between the electrodes and the conductive layer of the conductive particles more reliable, and to lower the connection resistance between the electrodes. Furthermore, when the conductive particles have an insulating material on their surface, or when the conductive particles are dispersed in a binder resin and used as a conductive material, the protrusions of the conductive particles can effectively remove the insulating material or binder resin between the conductive particles and the electrodes. This makes it possible to improve the conductivity reliability between the electrodes.

[0123] Methods for forming protrusions on the surface of the conductive particles include a method in which a core material is attached to the surface of the base particles and then a conductive layer is formed by electroless plating, and a method in which a conductive layer is formed on the surface of the base particles by electroless plating, a core material is attached, and then a conductive layer is formed by electroless plating. Furthermore, it is not necessary to use the core material to form the protrusions.

[0124] The conductive particles may include an insulating material disposed on the outer surface of the conductive layer. In this case, using conductive particles for connection between electrodes can prevent short circuits between adjacent electrodes. Specifically, when multiple conductive particles come into contact, an insulating material is present between the multiple electrodes, thus preventing short circuits between adjacent electrodes in the lateral direction rather than between upper and lower electrodes. Furthermore, when connecting electrodes, the insulating material between the conductive particles and the electrodes can be easily removed by applying pressure to the conductive particles with the two electrodes. If the conductive particles have protrusions on the surface of the conductive layer, the insulating material between the conductive layer and the electrodes can be removed even more easily. The insulating material is preferably an insulating resin layer or insulating particles, and more preferably insulating particles. The insulating particles are preferably insulating resin particles.

[0125] (Conductive materials) The conductive material described above comprises conductive particles and a binder resin. In the conductive material described above, the conductive particles comprise the aforementioned base particles and a conductive layer disposed on the surface of the base particles. The conductive particles are preferably dispersed in the binder resin and used as a conductive material. The conductive material is preferably an anisotropic conductive material. The conductive material is suitably used for the electrical connection of electrodes. The conductive material is preferably a circuit connection material.

[0126] The binder resin described above is not particularly limited. Any known insulating resin can be used as the binder resin. Examples of binder resins include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, and elastomers. Only one type of binder resin may be used, or two or more types may be used in combination.

[0127] Examples of vinyl resins include vinyl acetate resin, acrylic resin, and styrene resin. Examples of thermoplastic resins include polyolefin resin, ethylene-vinyl acetate copolymer, and polyamide resin. Examples of curable resins include epoxy resin, urethane resin, polyimide resin, and unsaturated polyester resin. The curable resin may be a room-temperature curing resin, a thermosetting resin, a photocuring resin, or a moisture-curing resin. The curable resin may be used in combination with a curing agent. Examples of thermoplastic block copolymers include styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, hydrogenated styrene-butadiene-styrene block copolymer, and hydrogenated styrene-isoprene-styrene block copolymer. Examples of elastomers include styrene-butadiene copolymer rubber and acrylonitrile-styrene block copolymer rubber.

[0128] In addition to the conductive particles and the binder resin, the above-mentioned conductive material may also contain various additives such as fillers, bulking agents, softeners, plasticizers, polymerization catalysts, curing catalysts, colorants, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, lubricants, antistatic agents, and flame retardants.

[0129] The method for dispersing the conductive particles in the binder resin is not particularly limited. Conventional dispersion methods can be used to disperse the conductive particles in the binder resin. Examples of methods for dispersing the conductive particles in the binder resin include the following: A method in which the conductive particles are added to the binder resin and then mixed and dispersed using a planetary mixer or the like. A method in which the conductive particles are uniformly dispersed in water or an organic solvent using a homogenizer or the like, then added to the binder resin and mixed and dispersed using a planetary mixer or the like. A method in which the binder resin is diluted with water or an organic solvent, then the conductive particles are added and mixed and dispersed using a planetary mixer or the like.

[0130] The conductive material described above can be used as a conductive paste, a conductive film, or the like. When the conductive material according to the present invention is a conductive film, a film without conductive particles may be laminated onto a conductive film containing conductive particles. The conductive paste is preferably an anisotropic conductive paste. The conductive film is preferably an anisotropic conductive film.

[0131] In 100% by weight of the conductive material, the content of the binder resin is preferably 10% by weight or more, more preferably 30% by weight or more, even more preferably 50% by weight or more, particularly preferably 70% by weight or more, preferably 99.99% by weight or less, and more preferably 99.9% by weight or less. When the content of the binder resin is above the lower limit and below the upper limit, conductive particles are efficiently arranged between electrodes, and the connection reliability of the connected members connected by the conductive material is further enhanced.

[0132] In 100% by weight of the above conductive material, the content of the above conductive particles is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, preferably 40% by weight or less, more preferably 20% by weight or less, and even more preferably 10% by weight or less. When the content of the above conductive particles is above the lower limit and below the upper limit, the conductivity reliability between electrodes is further improved.

[0133] (Connection structure) A connection structure can be obtained by connecting the members to be connected using the conductive particles described above, or using a conductive material containing the conductive particles and a binder resin described above.

[0134] The above-described connection structure comprises a first connection target member having a first electrode on its surface, a second connection target member having a second electrode on its surface, and a connection portion connecting the first connection target member and the second connection target member. In the above-described connection structure, the material of the connection portion includes conductive particles, and the conductive particles comprise the above-described base material particles and a conductive layer disposed on the surface of the base material particles. In the above-described connection structure, the first electrode and the second electrode are electrically connected by the conductive particles. Preferably, the connection portion is formed of conductive particles or of a conductive material containing conductive particles and a binder resin.

[0135] The first connection target member preferably has a first electrode on its surface. The second connection target member preferably has a second electrode on its surface. The first electrode and the second electrode are preferably electrically connected by the conductive particles.

[0136] Figure 4 is a schematic front cross-sectional view showing the connection structure using conductive particles as shown in Figure 2.

[0137] The connecting structure 51 shown in Figure 4 comprises a first member to be connected 52, a second member to be connected 53, and a connecting portion 54 connecting the first member to be connected 52 and the second member to be connected 53. The connecting portion 54 is formed of a conductive material containing conductive particles 11 and a binder resin. In Figure 4, the conductive particles 11 are shown schematically for illustrative purposes. Other conductive particles, such as conductive particles 21, may be used instead of conductive particles 11.

[0138] The first connection target member 52 has a plurality of first electrodes 52a on its surface (upper surface). The second connection target member 53 has a plurality of second electrodes 53a on its surface (lower surface). The first electrodes 52a and the second electrodes 53a are electrically connected by one or more conductive particles 11. Therefore, the first and second connection target members 52 and 53 are electrically connected by the conductive particles 11.

[0139] The method for manufacturing the above-mentioned connecting structure is not particularly limited. An example of a method for manufacturing the connecting structure is to place the conductive material between a first member to be connected and a second member to be connected, obtain a laminate, and then heat and pressurize the laminate. The pressure for the pressurization is 9.8 × 10⁻⁶. 4 Pa~4.9×10 6 The pressure is approximately Pa. The heating temperature is approximately 120°C to 220°C. The pressure used to connect the electrodes of the flexible printed circuit board, the electrodes placed on the resin film, and the electrodes of the touch panel is 9.8 × 10⁻⁶. 4 Pa~1.0×10 6 The resistance is approximately Pa. Because the connection structure according to the present invention is equipped with the above configuration, connection resistance can be reduced and conductivity reliability can be improved even when implemented at low voltage.

[0140] Specifically, the members to be connected include electronic components such as semiconductor chips, capacitors and diodes, as well as circuit boards such as printed circuit boards, flexible printed circuit boards, glass epoxy substrates and glass substrates. The conductive material is preferably a conductive material for connecting electronic components. The conductive paste is a paste-like conductive material and is preferably applied to the members to be connected in paste form.

[0141] The conductive particles and conductive materials described above are also suitably used in touch panels. Therefore, the connection target member is preferably a flexible substrate or a connection target member in which electrodes are arranged on the surface of a resin film. The connection target member is preferably a flexible substrate, and preferably a connection target member in which electrodes are arranged on the surface of a resin film. When the flexible substrate is a flexible printed circuit board or the like, the flexible substrate generally has electrodes on its surface.

[0142] Examples of electrodes provided on the above-mentioned connection target member include metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, silver electrodes, molybdenum electrodes, and tungsten electrodes. When the above-mentioned connection target member is a flexible substrate, the electrodes are preferably gold electrodes, nickel electrodes, tin electrodes, or copper electrodes. When the above-mentioned connection target member is a glass substrate, the electrodes are preferably aluminum electrodes, copper electrodes, molybdenum electrodes, or tungsten electrodes. In the case of aluminum electrodes, the electrodes may be made of aluminum alone, or they may be electrodes in which an aluminum layer is laminated on the surface of a metal oxide layer. Examples of materials for the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al, and Ga.

[0143] The present invention will be specifically described below with reference to examples and comparative examples. The present invention is not limited to the following examples.

[0144] The following materials were prepared. (Materials for polyorganosiloxanes) First alkoxysilane: vinyltrimethoxysilane (number of carbon atoms in the polymerizable unsaturated group: 2) Second alkoxysilane: Methyltrimethoxysilane (number of carbon atoms in the alkyl group: 1)

[0145] (1) Preparation of base particles (Example 1) In a 5000 mL separable flask equipped with a thermometer, dropping device, and stirrer, 1500 g of 0.13 wt% aqueous ammonia solution and 47 wt parts of the second alkoxysilane (methyltrimethoxysilane) were added and stirred at 20 rpm. Next, 53 wt parts of the first alkoxysilane (vinyltrimethoxysilane) were slowly added, and while stirring at 20 rpm, hydrolysis and polymerization reactions were allowed to proceed. Then, 10 mL of 25 wt% aqueous ammonia solution was gently added, and particles were isolated from the aqueous ammonia solution to obtain condensed particles. The obtained condensed particles were calcined at a calcination temperature of 300 °C and a calcination oxygen concentration of 20% for 2 hours to obtain base particles (core-shell particles) having carboxyl groups on their surface.

[0146] (Example 2) In a 5000 mL separable flask equipped with a thermometer, dropping device, and stirrer, 1500 g of 0.13 wt% aqueous ammonia solution and 68 wt parts of the first alkoxysilane (vinyltrimethoxysilane) were added and stirred at 20 rpm. Next, 32 wt parts of the second alkoxysilane (methyltrimethoxysilane) were slowly added, and while stirring at 20 rpm, hydrolysis and polymerization reactions were allowed to proceed. Then, 10 mL of 25 wt% aqueous ammonia solution was gently added, and particles were isolated from the aqueous ammonia solution to obtain condensed particles. The obtained condensed particles were calcined at a calcination temperature of 300 °C and a calcination oxygen concentration of 20% for 2 hours to obtain base particles (core-shell particles) having carboxyl groups on their surface.

[0147] (Examples 3-7) Except for changing the amounts of the first and second alkoxysilanes added, the calcination temperature of the condensate particles, and the calcination oxygen concentration as shown in Tables 1 and 3, base material particles (core-shell particles) having carboxyl groups on their surface were obtained in the same manner as in Example 1.

[0148] (Example 8) In a 5000 mL separable flask equipped with a thermometer, dropping device, and stirrer, 1500 g of 0.13 wt% aqueous ammonia solution, 35 wt parts of a first alkoxysilane (vinyltrimethoxysilane), and 65 wt parts of a second alkoxysilane (methyltrimethoxysilane) were slowly added. After allowing hydrolysis and polymerization reactions to proceed while stirring at 20 rpm, 10 mL of 25 wt% aqueous ammonia solution was gently added to isolate the particles from the aqueous ammonia solution, obtaining condensed particles. The obtained condensed particles were calcined at a calcination temperature of 580 °C and a calcination oxygen concentration of 15% for 2 hours to obtain base particles that are not core-shell particles but have carboxyl groups on their surface.

[0149] ( reference Examples 9-11 and Comparative Example 2) Except for changing the calcination temperature of the condensed particles as shown in Tables 3, 5, and 7, and changing the calcination oxygen concentration to 0%, substrate particles other than core-shell particles were obtained in the same manner as in Example 8.

[0150] (Comparative Example 1) 70 parts by weight of divinylbenzene copolymer resin particles ("Micropearl SP-203" manufactured by Sekisui Chemical Co., Ltd.) were mixed with 30 parts by weight of tetraethoxysilane. Hydrolysis and polymerization reactions were carried out while stirring at 30 rpm, and then 2.4 mL of 25% by weight aqueous ammonia solution was gently added. The particles were isolated from the aqueous ammonia solution to obtain base particles (core-shell particles).

[0151] (Comparative Example 3) In a 2 L flask equipped with a stirrer, reflux condenser, and thermometer, 110.0 g of benzoguanamine, 160.0 g of 37 wt% formalin, and 620 g of water were placed, and the pH was adjusted to 8.8 with 25 wt% aqueous ammonia to obtain a mixture. The mixture was heated while stirring, and the temperature was maintained at 70°C for 30 minutes to prepare an aqueous solution of the initial benzoguanamine condensate. Next, while maintaining the temperature at 70°C, a 10 wt% aqueous solution of p-toluenesulfonic acid monohydrate was added to the aqueous solution of the initial condensate to adjust the pH to 6.0. The temperature was then raised to 90°C and the curing reaction was continued for 3 hours. After cooling, the resulting reaction solution was filtered and dried to obtain white benzoguanamine resin particles.

[0152] (2) Preparation of conductive particles (Example 1~ 8, Reference example 9~ 11, and Comparative Examples 1-3) The obtained substrate particles were added to 500 parts by weight of distilled water and dispersed to obtain a dispersion. A nickel plating solution (pH 8.5) containing 0.14 mol / L nickel sulfate, 0.46 mol / L dimethylamine borane, and 0.2 mol / L sodium citrate was prepared. The obtained dispersion was stirred at 60°C, and the nickel plating solution was added to the dispersion dropwise at a dropping rate of 30 mL / min for 10 minutes to perform electroless nickel-boron alloy plating. After that, the dispersion was filtered to remove the particles, which were washed with water and dried to obtain conductive particles with a conductive layer (nickel-boron alloy, thickness 0.1 μm) on the surface of the substrate particles.

[0153] (Example 12) The substrate particles obtained in Example 4 were added to 500 parts by weight of distilled water and dispersed to obtain a dispersion. Next, 1 g of nickel particle slurry (average particle size 150 nm) was added to the dispersion over 3 minutes to obtain substrate particles with a core material attached. A nickel plating solution (pH 5.0) containing 0.19 mol / L nickel sulfate, 0.21 mol / L sodium hypophosphite, and 0.08 mol / L sodium citrate was prepared as the nickel plating solution. While stirring the obtained dispersion at 45°C, the nickel plating solution was added dropwise to the dispersion at a dropping rate of 50 ml / min to perform electroless nickel plating. After that, the dispersion was filtered to remove the particles, which were washed with water and dried to obtain conductive particles with a nickel-phosphorus conductive layer (thickness 0.1 μm) on the surface of the substrate particles.

[0154] (Example 13) Ten parts by weight of the substrate particles obtained in Example 4 were added to 100 parts by weight of an alkaline solution containing 5% by weight of palladium catalyst solution, dispersed using an ultrasonic disperser, and the substrate particles were removed by filtering the solution. Next, the substrate particles were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surface of the substrate particles. After thoroughly washing the activated substrate particles with water, they were added to 500 parts by weight of distilled water and dispersed to obtain a dispersion.

[0155] As an electroless high-purity nickel plating solution, a mixture containing 0.21 mol / L nickel chloride, 1.54 mol / L hydrazinium sulfate, 0.32 mol / L boric acid, and 0.08 mol / L sodium citrate was prepared, and the pH was adjusted to 10.5 with sodium hydroxide. 500 ml of the above electroless high-purity nickel plating solution was added dropwise to a dispersion at a dropping rate of 30 ml / min to perform electroless high-purity nickel plating. The reaction temperature at this time was set to 60°C. After that, the mixture was stirred until the pH stabilized and it was confirmed that hydrogen foaming had stopped. Subsequently, the dispersion was filtered to remove the particles, which were washed with water and dried to obtain conductive particles in which a conductive layer (high-purity nickel, thickness 0.1 μm) was arranged on the surface of the substrate particles. The conductive portion of the obtained conductive particles had plate-like protrusions on the outer surface.

[0156] (Example 14) Ten parts by weight of the substrate particles obtained in Example 4 were added to 100 parts by weight of an alkaline solution containing 5% by weight of palladium catalyst solution, dispersed using an ultrasonic disperser, and the substrate particles were removed by filtering the solution. Next, the substrate particles were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surface of the substrate particles. After thoroughly washing the activated substrate particles with water, they were added to 500 parts by weight of distilled water and dispersed to obtain a suspension (0).

[0157] A nickel plating solution (1) (pH 8.5) was prepared containing 0.14 mol / L nickel sulfate, 0.46 mol / L dimethylamine borane, and 0.2 mol / L sodium citrate. The above suspension (0) was stirred at 60°C, and the nickel plating solution (1) was gradually added dropwise to the suspension (0) to perform electroless nickel-boron alloy plating and obtain suspension (1).

[0158] Next, a nickel plating solution (2) (pH 8.0) containing 0.14 mol / L nickel sulfate and 0.45 mol / L hydrazine was prepared. While stirring the suspension (1) at 65°C, the nickel plating solution (2) was gradually added dropwise to the suspension (1) to perform electroless nickel plating and obtain suspension (2).

[0159] A nickel plating solution (3) (pH 8.0) was prepared containing 0.14 mol / L nickel sulfate, 0.09 mol / L sodium stannate trihydrate, and 0.45 mol / L sodium gluconate. The above suspension (2) was stirred at 65°C, and the above nickel plating solution (3) was gradually added dropwise to the above suspension (2) to perform electroless nickel-tin alloy plating and obtain suspension (3).

[0160] Subsequently, the suspension (3) was filtered to remove the particles, which were then washed with water and dried to obtain conductive particles in which a conductive layer (nickel-tin alloy, 0.1 μm thick) was arranged on the surface of the base particles.

[0161] (3) Fabrication of connecting structures The following materials were mixed: 10 parts by weight of bisphenol A type epoxy resin (Mitsubishi Chemical Corporation's "Epicoat 1009"); 40 parts by weight of acrylic rubber (weight-average molecular weight approximately 800,000); 200 parts by weight of methyl ethyl ketone; 50 parts by weight of microencapsulated curing agent (Asahi Kasei E-Materials Corporation's "HX3941HP"); and 2 parts by weight of silane coupling agent (Toray Dow Corning Silicone Corporation's "SH6040"). Conductive particles were added to the resulting mixture to a content of 3% by weight and dispersed to obtain a resin composition.

[0162] The obtained resin composition was applied to a 50 μm thick PET (polyethylene terephthalate) film with one side treated for mold release, and dried with hot air at 70°C for 5 minutes to produce an anisotropic conductive film. The thickness of the obtained anisotropic conductive film was 12 μm.

[0163] The obtained anisotropic conductive film was cut to a size of 5 mm x 5 mm. The cut anisotropic conductive film was attached to approximately the center of the aluminum electrode (height 0.2 μm, L / S = 20 μm / 20 μm) on a glass substrate (width 3 cm, length 3 cm) which had a wire for resistance measurement on one end. Next, a two-layer flexible printed circuit board (width 2 cm, length 1 cm) with the same aluminum electrode was aligned so that the electrodes overlapped and then attached. This laminate of the glass substrate and the two-layer flexible printed circuit board was heat-pressed under the conditions of 40 N, 180 °C, and 15 seconds of pressure bonding to obtain a connecting structure.

[0164] (evaluation) (1) Ratio in polyorganosiloxane (number of silicon atoms with a 2-bridge structure / number of silicon atoms with a 3-bridge structure) The obtained substrate particles were analyzed using an NMR spectral analyzer (JEOL "ECX400") to determine their solid state. 29 Si-NMR measurements were performed (measurement frequency: 79.4254 MHz, pulse width: 3.7 μs, sample holder: 8 mm, sample rotation speed: 7 kHz, number of integrations: 3600, measurement temperature: 25 °C). The ratio (number of silicon atoms with a 2-bridge structure / number of silicon atoms with a 3-bridge structure) in the polyorganosiloxane was determined using the method described above.

[0165] (2) Particle size of the base material particles For the obtained substrate particles, the particle size distribution was measured for approximately 100,000 particles using a particle size distribution analyzer (Beckman Coulter's "Multisizer 4"), and the average particle size was determined.

[0166] (3) Compressive modulus of the base material particles (10% K value at 20°C, 20% K value at 20°C, 30% K value at 20°C, and 20% K value at 150°C), and compressive load value (10% load value at 20°C, 20% load value at 20°C, and 30% load value at 20°C) The compressive modulus and compressive load values ​​of the obtained base material particles were measured using a microcompression tester (Fischer Scope H-100, manufactured by Fischer) according to the method described above. In addition, the ratio (20%K value at 150°C / 20%K value at 20°C), the ratio (absolute difference between the 10%K value at 20°C and the 20%K value at 20°C / absolute difference between the 20%K value at 20°C and the 30%K value at 20°C), and the ratio (30% load value at 20°C / 10% load value at 20°C) were determined.

[0167] (4) Compression recovery rate of the substrate particles (20% compression recovery rate at 20°C and 20% compression recovery rate at 150°C) and fracture strain The compression recovery rate and fracture strain of the obtained substrate particles were measured at 20°C and 150°C using a microcompression tester (Fischerscope H-100, manufactured by Fischer) according to the method described above. The ratio (20% compression recovery rate at 150°C / 20% compression recovery rate at 20°C) was also calculated.

[0168] (5) Static contact angle of water with substrate particles Using a contact angle meter (Matsubo Co., Ltd. "Contact Angle Meter PG-X"), the static contact angle was measured at 20°C by dropping 100 μL of pure water onto substrate particles supported on adhesive tape.

[0169] (6) Compression modulus of conductive particles (10%K value at 20°C, 20%K value at 20°C, and 30%K value at 20°C) The compressive modulus of the obtained conductive particles was measured using a microcompression tester (Fischerscope H-100, manufactured by Fischer GmbH) according to the method described above.

[0170] (7) Condition of the indentation In the obtained connection structure, the electrodes provided on the glass substrate were observed from the glass substrate side of the connection structure using a differential interference microscope to check for the formation of indentations on the electrodes that came into contact with the conductive particles. After leaving the structure in an 85°C, 85% atmosphere for 100 hours, the presence or absence of indentations on the electrodes that came into contact with the conductive particles was observed again in the same manner. The state of the indentations was judged according to the following criteria.

[0171] [Criteria for determining the condition of indentations] ○○○: Out of 50 electrodes, the number of electrodes that did not show a clear indentation in the connection structure before heating was 0, and the number of electrodes that did not show a clear indentation in the connection structure after heating was 0. ○○: Out of 50 electrodes, the number of electrodes that do not show a clear indentation in the connection structure before heating is 0, and the number of electrodes that do not show a clear indentation in the connection structure after heating is 1 or more but less than 5. ○: Out of 50 electrodes, 0 electrodes showed no clear indentation on the connection structure before heating, and 5 or more electrodes showed no clear indentation on the connection structure after heating. △: Out of 50 electrodes, the number of electrodes where no clear indentation is visible on the connection structure before heating is between 1 and 5. ×: Out of 50 electrodes, 5 or more electrodes do not show a clear indentation on the connection structure before heating.

[0172] (8) Contact area between conductive particles and electrodes For the obtained connection structure, the cross-sections of three conductive particles were observed using a focused ion beam scanning electron microscope (FIB-SEM), and the average ratio of the length of the portion of the conductive particle in contact with the upper and lower electrodes to 100% of the circumference of the conductive particle was calculated. The contact area between the conductive particle and the electrode was determined according to the following criteria.

[0173] [Evaluation criteria for the contact area between conductive particles and electrodes] ○○○: The proportion of the length of the part where the conductive particles are in contact with the upper and lower electrodes is 50% or more. ○○: The ratio of the length of the part where the conductive particles are in contact with the upper and lower electrodes is less than 50% and 40% or more. ○: The ratio of the length of the part in contact with the upper and lower electrodes of the conductive particles is less than 40% and 30% or more. △: The ratio of the length of the part where the conductive particles are in contact with the upper and lower electrodes is less than 30% but 20% or more. ×: The proportion of the length of the conductive particles in contact with the upper and lower electrodes is less than 20%.

[0174] (9) Initial connection resistance The connection resistance A between opposing electrodes of the obtained connection structure was measured using the four-terminal method. The initial connection resistance was determined according to the following criteria.

[0175] [Criteria for evaluating initial connection resistance] ○○○: Connection resistance A is 2.0Ω or less ○○: Connection resistance A is greater than 2.0Ω and less than or equal to 3.0Ω. ○: Connection resistance A exceeds 3.0Ω and is 5.0Ω or less. △: Connection resistance A exceeds 5.0Ω and is 10.0Ω or less. ×: Connection resistance A exceeds 10.0Ω

[0176] (10) Continuity reliability The obtained connection structures were left at 85°C and 85% (high temperature and high humidity) for 500 hours. The connection resistance B between opposing electrodes of the connection structures after the period of time was measured using the four-terminal method. The continuity reliability of the connection structures was determined according to the following criteria.

[0177] [Evaluation Criteria for Conductivity Reliability] ○○○: The ratio of connection resistance B to connection resistance A is less than 1.0. ○○: The ratio of connection resistance B to connection resistance A is 1.0 or greater and less than 1.5. ○: The ratio of connection resistance B to connection resistance A is 1.5 or greater and less than 2.0. △: The ratio of connection resistance B to connection resistance A is 2.0 or greater and less than 5.0. ×: The ratio of connection resistance B to connection resistance A is 5.0 or greater.

[0178] Details and results regarding the base particles and conductive particles are shown in Tables 1-8 below.

[0179] [Table 1]

[0180] [Table 2]

[0181] [Table 3]

[0182] [Table 4]

[0183] [Table 5]

[0184] [Table 6]

[0185] [Table 7]

[0186] [Table 8] [Explanation of Symbols]

[0187] 1...Base material particles 2…Conductive layer 11... Conductive particles 21... Conductive particles 21a...Protrusion 22...Conductive layer 22a...protrusion 23…core substance 24…Insulating material 51…Connection structure 52...First connection target member 52a...First electrode 53...Second connection target member 53a...Second electrode 54…Connection part

Claims

1. These are substrate particles containing polyorganosiloxane. The ratio of the number of silicon atoms having a two-bridged structure to the number of silicon atoms having a three-bridged structure in the polyorganosiloxane is 0.3 or more and 1.5 or less. The compressive modulus when compressed by 10% at 20°C is 10,000 N / mm². ２ More than 30000N / mm ２ The following: Substrate particles in which the ratio of the absolute value of the difference between the compressive modulus when compressed by 10% at 20°C and the compressive modulus when compressed by 20% at 20°C to the absolute value of the difference between the compressive modulus when compressed by 20% at 20°C and the compressive modulus when compressed by 30% at 20°C is 1.0 or greater.

2. A base particle containing a polyorganosiloxane, The ratio of the number of silicon atoms having a two-bridged structure to the number of silicon atoms having a three-bridged structure in the polyorganosiloxane is 0.3 or more and 1.5 or less. The compressive modulus when compressed by 10% at 20°C is between 10,000 N / mm² and 30,000 N / mm². The base particles have carboxyl groups on their surface. Substrate particles in which the contact angle of water with respect to the substrate particles is between 10° and 90°.

3. The ratio of the load value when compressed by 30% at 20°C to the load value when compressed by 10% at 20°C is 4.0 or less. The substrate particles according to claim 1 or 2, wherein the fracture strain is 10% or more and 40% or less.

4. The substrate particles according to claim 1 or 2, wherein the ratio of the absolute value of the difference between the compressive modulus when compressed by 10% at 20°C and the compressive modulus when compressed by 20% at 20°C to the absolute value of the difference between the compressive modulus when compressed by 20% at 20°C and the compressive modulus when compressed by 30% at 20°C is 1.0 or more and 10.0 or less.

5. The base particle according to claim 1 or 2, wherein the ratio of the compressive modulus when compressed by 20% at 150°C to the compressive modulus when compressed by 20% at 20°C is 0.40 or more.

6. The compression recovery rate when compressed by 20% at 20°C is 60% or more. The base particle according to claim 1 or 2, wherein the ratio of the compression recovery rate when compressed by 20% at 150°C to the compression recovery rate when compressed by 20% at 20°C is 0.30 or more and 0.90 or less.

7. The base particle according to claim 1 or 2, wherein the particle size is 1.0 μm or more and 5.0 μm or less.

8. The base particle according to claim 1 or 2, wherein the polyorganosiloxane material comprises a first alkoxysilane having polymerizable unsaturated groups and a second alkoxysilane not having polymerizable unsaturated groups.

9. It comprises a core and a shell disposed on the surface of the core, The base particle according to claim 1 or 2, which is a core-shell particle.

10. The base particle is used to obtain conductive particles having the conductive layer, wherein a conductive layer is formed on the surface of the base particle.

11. The base particles according to claim 1 or 2, A conductive particle comprising a conductive layer disposed on the surface of the aforementioned substrate particle.

12. The conductive particle according to claim 11, comprising an insulating material disposed on the outer surface of the conductive layer.

13. The conductive particle according to claim 11, having protrusions on the outer surface of the conductive layer.

14. It comprises conductive particles and a binder resin. A conductive material comprising a base particle according to claim 1 or 2 and a conductive layer disposed on the surface of the base particle.

15. A first connection target member having a first electrode on its surface, A second connection target member having a second electrode on its surface, It comprises a connecting portion that connects the first member to be connected and the second member to be connected, The material of the connecting portion contains conductive particles, The conductive particles comprise a base particle according to claim 1 or 2 and a conductive layer disposed on the surface of the base particle, A connection structure in which the first electrode and the second electrode are electrically connected by the conductive particles.

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