JP5571271B1 - Base particle, conductive particle, conductive material, and connection structure - Google Patents

Abstract

When the conductive particles having a conductive layer formed on the surface are used to electrically connect the electrodes, the base particles that can reduce the connection resistance and suppress the occurrence of cracks in the electrodes provide.
The substrate particles (11) according to the present invention are used for obtaining conductive particles (1) having a conductive layer (2) formed on the surface and having the conductive layer (2). The base particle (11) is a core-shell particle including a core (12) and a shell (13) disposed on the surface of the core (12). The compression recovery rate of the base particles (11) is 50% or more. The compression elastic modulus when the substrate particles (11) are compressed by 10% is 3000 N / mm 2 or more and less than 6000 N / mm 2. The ratio of the load value when the substrate particles (1) are compressed by 30% to the load value when compressed by 10% is 3 or less.

Description

  The present invention relates to a base material particle having a conductive layer formed on the surface and used for obtaining conductive particles having the conductive layer. The present invention also relates to a conductive particle, a conductive material, and a connection structure using the base particle.

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

  The anisotropic conductive material is used to electrically connect electrodes of various connection target members such as a flexible printed circuit (FPC), a glass substrate, a glass epoxy substrate, and a semiconductor chip to obtain a connection structure. ing. Moreover, as the conductive particles, conductive particles having base particles and a conductive layer disposed on the surface of the base particles may be used.

  As an example of the base particles used for the conductive particles, in Patent Document 1 below, the shell is an inorganic compound (A), the core is an organic polymer (b), and the core is covered with the shell. Polymer particles (B) (substrate particles) are disclosed. Patent Document 1 also discloses conductive particles in which organic polymer particles (B) are coated with a conductive metal (C).

  Patent Document 2 listed below discloses organic-inorganic composite particles (base particles) obtained by hydrolysis and polycondensation of a polyfunctional silane compound having a polymerizable unsaturated group in the presence of a surfactant. ) Is disclosed. In Patent Document 2, the polyfunctional silane compound is at least one radical polymerizable group-containing first silicon compound selected from a compound represented by the following formula (X) and a derivative thereof.

  In said formula (X), R1 shows a hydrogen atom or a methyl group, R2 shows the C1-C20 bivalent organic group which may have a substituent, R3 is C1-C5 R 4 represents an alkyl group or a phenyl group, and R 4 represents at least one monovalent group selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, and an acyl group having 2 to 5 carbon atoms.

  Patent Document 3 below discloses core-shell particles in which the surface of hard particles is covered with a soft polymer layer. Preferable examples of the hard particles include metal particles such as nickel, inorganic particles such as glass fiber, alumina and silica, and resin cured particles such as cured benzoguanamine. Patent Document 3 describes that by providing a soft polymer layer, the contact area can be increased and the reliability can be improved.

JP 2006-156068 A JP 2000-204119 A Japanese Patent Laid-Open No. 7-140481

  In recent years, the distance between electrodes connected by conductive particles tends to be narrow and the electrode area tends to be small, and there is a demand for conductive particles that can be connected with even lower resistance. As for the substrate material, a relatively soft resin film substrate has been used instead of a glass substrate in order to enhance flexibility, and conductive particles that do not damage the soft substrate and the electrode are required. It is coming.

  If conductive particles whose surfaces of flexible substrate particles are covered with a conductive layer are used, the contact area between the electrode and the conductive particle is increased, and the conductive particle is less likely to damage the electrode. However, when simply using flexible base particles, the binder resin between the electrodes and the conductive particles cannot be sufficiently removed when the electrodes are connected, and the resin is sandwiched between the electrodes and the conductive particles. Or the conductive layer and the oxide film on the surface of the electrode cannot be sufficiently penetrated, resulting in a problem that the connection resistance is increased. This problem occurs even when core-shell particles in which the core is covered with a shell and the shell is a relatively soft organic shell are used as the base particles.

  On the other hand, when conductive particles in which the surface of relatively hard base particles such as silica are coated with a conductive layer are used, the exclusion property of the binder resin and the penetrability of the oxide film on the surface of the conductive layer and the electrode are Become good. However, since the conductive particles are not sufficiently deformed, there is a problem that the contact area between the electrode and the conductive particles is not sufficiently large, and the connection resistance is not sufficiently low. Moreover, depending on the pressure bonding conditions at the time of connection between the electrodes, the conductive particles may damage the electrodes and cause cracks in the electrodes.

  In addition, conductive particles having poor resilience (recovery rate) after compression adversely affect connection reliability. If the connection structure in which the electrodes are connected using conductive particles that are poorly restored after compression is stored under high-temperature and high-humidity conditions, there is a problem that poor connection tends to occur.

  The object of the present invention is to reduce the connection resistance and suppress the occurrence of cracks in the electrodes when the electrodes are electrically connected using conductive particles having a conductive layer formed on the surface. It is providing the base particle which can be manufactured. Moreover, the objective of this invention is providing the electroconductive particle using the said base material particle, an electroconductive material, and a connection structure.

According to a wide aspect of the present invention, there is provided a base particle having a conductive layer formed on a surface and used for obtaining conductive particles having the conductive layer, the core being disposed on the surface of the core and a core-shell particles having a shell, a compression recovery rate is 50% or more, 10% compressed compression elastic modulus when the 3000N / mm ² or more and less than 6000 N / mm ^2, when compressed 30% The base material particle | grains whose ratio with respect to the load value when compressing 10% of the load value of is 3 or less are provided.

  On the specific situation with the base particle which concerns on this invention, the said core is an organic core and the said shell is an inorganic shell.

  On the specific situation with the base particle which concerns on this invention, the thickness of the said shell is 100 nm or more and 5 micrometers or less.

It is preferable that the compression elastic modulus when the base particle is compressed by 30% is 3000 N / mm ² or less. It is preferable that the ratio of the load value when the base material particle is compressed by 40% to the load value when the base material particle is compressed by 10% is 6 or less. The fracture strain of the substrate particles is preferably 10% or more and 30% or less.

  According to a wide aspect of the present invention, there is provided a conductive particle comprising the above-described base particle and a conductive layer disposed on the surface of the base particle.

  On the specific situation with the electroconductive particle which concerns on this invention, this electroconductive particle is further equipped with the insulating substance arrange | positioned on the outer surface of the said conductive layer.

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

  According to a wide aspect of the present invention, the conductive particles include conductive particles and a binder resin, and the conductive particles include the base material particles described above and a conductive layer disposed on the surface of the base material particles. A conductive material is provided.

  According to a wide aspect of the present invention, a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, the first connection target member, and the A connection portion connecting the second connection target member, and the connection portion is formed of conductive particles or formed of a conductive material including the conductive particles and a binder resin. The conductive particles include the base material particles described above and a conductive layer disposed on the surface of the base material particles, and the first electrode and the second electrode are electrically connected by the conductive particles. A connection structure is provided which is connected in a connected manner.

The base material particle according to the present invention is a core-shell particle including a core and a shell disposed on the surface of the core, and the base material particle according to the present invention has a compression recovery rate of 50% or more, 10% compressed compression elastic modulus when the 3000N / mm ² or more and less than 6000 N / mm ^2, since the ratio load value when compressed 10% of the load value when compressed 30% is 3 or less When the electrodes are electrically connected using conductive particles having a conductive layer formed on the surface, the connection resistance can be lowered and the occurrence of cracks in the electrodes can be suppressed.

FIG. 1 is a cross-sectional view showing conductive particles according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing conductive particles according to the second embodiment of the present invention. FIG. 3 is a cross-sectional view showing conductive particles according to the third embodiment of the present invention. FIG. 4 is a front cross-sectional view schematically showing a connection structure using conductive particles according to the first embodiment of the present invention.

  Details of the present invention will be described below.

(Base particle)
The substrate particles according to the present invention are used for obtaining conductive particles having a conductive layer formed on the surface and having the conductive layer. That is, the base particle according to the present invention is a base particle for conductive particles. The base particle according to the present invention includes a core and a shell disposed on the surface of the core. The base particle according to the present invention is a core-shell particle.

The compression recovery rate of the base particles according to the present invention is 50% or more. Compression modulus when the base particles according to the present invention was compressed 10% (10% K value) of 3000N / mm ² or more and less than 6000 N / mm ^2. Ratio (30% load value / 10% load value) of the load value (30% load value) when the substrate particles according to the present invention are compressed 30% to the load value (10% load value) when 10% compressed Is 3 or less.

  The base particles according to the present invention have a high compression recovery rate, and the base particles have an appropriate hardness in the initial stage of compression. Furthermore, in the base particle which concerns on this invention, hardness changes in the stage compressed to some extent, and a more flexible property is expressed. For this reason, deformation in the middle period (30% compression deformation time point) occurs at a load value that is not much different from the load value at the initial deformation time point (10% compression deformation time point). As a result, when the electrodes are electrically connected using conductive particles having a conductive layer formed on the surface of the substrate particles, the binder resin is sufficiently eliminated by the hardness that is initially expressed, and the conductive layer Alternatively, the oxide film on the surface of the electrode can be sufficiently penetrated, and the contact area between the electrode and the conductive particles can be sufficiently increased due to the flexibility in the middle period. For this reason, the connection resistance between electrodes can be made low and the connection 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 unlikely to increase and connection failure is unlikely to occur. Further, due to the mid-term flexibility, damage to the electrode and the substrate due to the conductive particles can be suppressed. Therefore, connection failure due to generation of cracks in the electrode can be suppressed by using the base particles according to the present invention.

  The compression recovery rate of the substrate particles is 50% or more. The compression recovery rate is preferably 52% or more. When the compression recovery rate is equal to or higher than the lower limit, the conductive particles are easily followed and deformed corresponding to the variation in the distance between the electrodes. For this reason, it becomes difficult to produce the connection failure between electrodes.

  The compression recovery rate can be measured as follows.

  Spread base particles on the sample stage. About one spread | diffused base material particle, a load (reverse load value) is given to the center direction of a base material particle until a base material particle compresses and deforms 30% using a micro compression tester. Thereafter, unloading is performed up to the origin load value (0.40 mN). The load-compression displacement during this period is measured, and the compression recovery rate can be obtained from the following equation. The load speed is 0.33 mN / sec. As the micro compression tester, for example, “Fischer Scope H-100” manufactured by Fischer is used.

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

The 10% K value 3000N / mm ² or more and less than 6000 N / mm ^2. The 10% K value is preferably 3200 N / mm ² or more, more preferably 3500 N / mm ² or more, preferably 5800 N / mm ² or less, more preferably 5500 N / mm ² or less. When the 10% K value is equal to or more than the lower limit, the binder resin is effectively eliminated and the conductive film or the oxide film on the surface of the electrode is effectively penetrated, so that the connection resistance between the electrodes is effectively low. Become. When the 10% K value is less than or equal to the above upper limit, cracks are more unlikely to occur in the electrode. When the 10% K value is 3500 N / mm ² or more, the connection resistance is effectively reduced.

  The ratio of the 30% load value to the 10% load value (30% load value / 10% load value) is 3.0 or less. The ratio (30% load value / 10% load value) is more preferably 2.9 or less. When the ratio (30% load value / 10% load value) is less than or equal to the above upper limit, the contact area between the electrode and the conductive particles is sufficiently large, the connection resistance between the electrodes is effectively reduced, and the electrode The connection reliability between them becomes even higher. The ratio (30% load value / 10% load value) is preferably 1.5 or more.

Compression modulus when the base particle and 30% compressive deformation (30% K value) preferably 3000N / mm ² or less, and more preferably not more than 2500N / mm ^2. When the 30% K value is less than or equal to the above upper limit, the contact area between the conductive particles and the electrode is further increased, and cracks are more unlikely to occur in the electrode. The 30% K value is preferably 500 N / mm ² or more. When the 10% K value is 3000 N / mm ² or less, cracks are more unlikely to occur in the electrode. When the 10% K value is 2500 N / mm ² or less, cracks are hardly generated in the electrode.

  The ratio (40% load value / 10% load value) of the load value (40% load value) when the base particle is compressed 40% to the load value (10% load value) when 10% compressed is preferable. 6 or less, more preferably 5 or less. When the ratio (40% load value / 10% load value) is less than or equal to the above upper limit, the design width for improving connection reliability is further increased. When the ratio (40% load value / 10% load value) is equal to or lower than the upper limit, the connection resistance is effectively reduced. The ratio (40% load value / 10% load value) is preferably 2 or more.

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

  Using a micro-compression tester, the substrate particles are compressed under the conditions of a smooth indenter end face of a cylinder (diameter 100 μm, made of diamond) at 25 ° C., a compression rate of 0.3 mN / sec, and a maximum test load of 20 mN. The load value (N) and compression displacement (mm) at this time are measured. From the measured value obtained, the compression elastic modulus can be obtained by the following formula. As the micro compression tester, for example, “Fischer Scope H-100” manufactured by Fischer is used.

10% K value or 30% K value (N / mm ² ) = (3/2 ^1/2 ) · F · S ⁻³ / 2 · R ^{− 1/2}
F: Load value (N) when the base particle is 10% or 30% compressively deformed
S: Compression displacement (mm) when the substrate particles are 10% or 30% compressively deformed
R: radius of base particle (mm)

  The compression elastic modulus represents the hardness of the base particle universally and quantitatively. By using the compression elastic modulus, the hardness of the base particle can be expressed quantitatively and uniquely.

  The fracture strain of the substrate particles is 10% or more and 30% or less. When the compression behavior of the particles is evaluated, a point at which the displacement greatly changes at a certain load value is observed. The load value at this changing point is the breaking load value, and the displacement amount is the breaking displacement. The ratio of the fracture displacement to the particle size before compression (fracture displacement / particle size before compression) × 100 is defined as fracture strain (%). For example, when the fracture behavior of a particle having a particle size of 5 μm before compression is observed when the displacement is 1 μm, the fracture strain is calculated as 20%. In the case of core-shell particles, the fracture behavior of the shell is generally observed at the initial stage of displacement. When the breaking strain is equal to or higher than the lower limit, the exclusion property of the binder resin, the penetrability of the conductive layer and the oxide film of the electrode are further enhanced, and the connection resistance is further lowered. When the fracture strain is less than or equal to the above upper limit, mid-term flexibility is exhibited, the contact area between the conductive particles and the electrode is further increased, and the connection resistance is further decreased.

  The fracture strain can be evaluated from the measurement of the compression elastic modulus described above, and can be measured by reading the amount of displacement at the discontinuity point of the compression displacement curve.

  The particle size of the core is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 500 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less, particularly preferably 20 μm or less, and most preferably 10 μm or less. . When the core particle size is not less than the above lower limit and not more than the above upper limit, 10% K value, 30% K value, the above ratio (30% load value / 10% load value) and the above ratio (40% load value / 10) % Load value) is easy to show a suitable value, and the base particles can be suitably used for the use of conductive particles. For example, when the core particle size is not less than the lower limit and not more than the upper limit, when the electrodes are connected using the conductive particles, the contact area between the conductive particles and the electrodes is sufficiently large, and Aggregated conductive particles are hardly formed when the conductive layer is formed. Further, the distance between the electrodes connected via the conductive particles does not become too large, and the conductive layer is difficult to peel from the surface of the base material particles.

  The particle diameter of the core means a diameter when the core is a true sphere, and when the core is a shape other than a true sphere, means a diameter when assuming a true sphere corresponding to the volume. To do. Moreover, the particle size of a core means the average particle size which measured the core with the arbitrary particle size measuring apparatus. For example, a particle size distribution measuring machine using principles such as laser light scattering, electrical resistance value change, and image analysis after imaging can be used.

  The base particle is a core-shell particle including a core and a shell disposed on the surface of the core. The core shell particle compression recovery rate, 10% K value, 30% K value, the above ratio (30% load value / 10% load value) and the above ratio (40% load value / 10% load value) satisfy the above-mentioned values. By doing so, the connection resistance between electrodes can be made low and the connection reliability between electrodes can be improved.

  The core is preferably an organic core. The shell is preferably an inorganic shell. It is preferable that the core is an organic core and the shell is an inorganic shell. The substrate particles include an organic core and an inorganic shell disposed on the surface of the organic core, and are preferably core-shell particles, and are preferably core-shell type organic-inorganic hybrid particles. When the core is an organic core or the shell is an inorganic shell, the compression recovery rate, 10% K value, 30% K value, the ratio (30% load value / 10% load value) and the ratio ( (40% load value / 10% load value) can easily satisfy the above-described value.

  The core is preferably an organic core, and is preferably an organic particle. Since the organic core and the organic particles are relatively soft compared to the inorganic core and the inorganic particles, a shell is formed on the surface of the relatively soft organic core. It is easy to satisfy (load value / 10% load value) and the above ratio (40% load value / 10% load value).

  Various organic materials are suitably used as a material for forming the organic core. Examples of the material for forming the organic core include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polypropylene, polyisobutylene, and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; Polymerize one or more of polyalkylene terephthalate, polysulfone, polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, and various polymerizable monomers having ethylenically unsaturated groups The polymer obtained by making it use is used. Easily design and synthesize base particles with any compression properties suitable for conductive materials by polymerizing one or more of various polymerizable monomers having ethylenically unsaturated groups It is.

  When the organic core is obtained by polymerizing a monomer having an ethylenically unsaturated group, the monomer having an ethylenically unsaturated group may be a non-crosslinkable monomer or a crosslinkable monomer. And a polymer.

  Examples of the non-crosslinkable monomer include styrene monomers such as styrene and α-methylstyrene; carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, and maleic anhydride; (Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl ( Alkyl (meth) acrylates such as meth) acrylate and isobornyl (meth) acrylate; oxygen such as 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate and glycidyl (meth) acrylate (Meth) acrylates; nitrile-containing monomers such as (meth) acrylonitrile; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether; vinyl acids such as vinyl acetate, vinyl butyrate, vinyl laurate, vinyl stearate Esters; Unsaturated hydrocarbons such as ethylene, propylene, isoprene and butadiene; Halogen-containing monomers such as trifluoromethyl (meth) acrylate, pentafluoroethyl (meth) acrylate, vinyl chloride, vinyl fluoride and chlorostyrene Is mentioned.

  Examples of the crosslinkable monomer include tetramethylolmethane tetra (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and dipenta Erythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) Polyfunctional (meth) acrylates such as acrylate, (poly) tetramethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate; triallyl (iso) cyanure And silane-containing monomers such as triallyl trimellitate, divinylbenzene, diallyl phthalate, diallylacrylamide, diallyl ether, γ- (meth) acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, vinyltrimethoxysilane It is done.

  The organic core can be obtained by polymerizing the polymerizable monomer having an ethylenically unsaturated group by a known method. Examples of this method include a method of suspension polymerization in the presence of a radical polymerization initiator, and a method of polymerizing by swelling a monomer together with a radical polymerization initiator using non-crosslinked seed particles.

In particular, with regard to the optimal core in the present invention, the compression modulus when the core is compressed 10% (10% K value), preferably 1500 N / mm ² or more and 4000 N / mm ² or less, more preferably 2000N / mm ² or more and 3500 N / mm ² or less. The compression recovery rate of the core is preferably 50% or more, more preferably 55% or more. If the core satisfies the 10% K value or the compression modulus, the 10% K value of the base particle having the core covered with an inorganic shell, the ratio (10% load value / 30% load value) and the compression recovery rate can be easily controlled within a suitable range.

  The method for designing the physical properties of the core within the above-mentioned range is not limited. For example, when the monomer is obtained by polymerizing a monomer having an ethylenically unsaturated group, a (meth) acryloyl group is used as a compound for forming the core. And a method using 50% by weight or more of a crosslinkable monomer having a flexible structure such as an ethylene glycol structure or a methylene structure. Examples of such crosslinkable monomers include (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, (poly) tetramethylene di (meth) acrylate, and 1,4-butane. Examples include diol di (meth) acrylate. In a core obtained by using 70% by weight or more of a crosslinkable monomer having a rigid structure such as divinylbenzene, the 10% K value tends to be high. In addition, a monomer having an ethylenically unsaturated group is absorbed into a granulated product obtained by polycondensing a silane coupling agent such as vinyltrimethoxysilane or (meth) acryloxytrimethoxysilane by a sol-gel technique. After that, it is possible to design the core physical properties to optimum values even for the particles obtained by polymerization. The material constituting the core may contain not only an organic compound but also a compound having a silicon atom. The ratio of the carbon atom content in the core to the silicon atom content (carbon atom content / silicon atom content) is preferably 1.2 or more. A core having the above ratio (carbon atom content / silicon atom content) of 1.2 or more corresponds to an organic core.

  From the viewpoint of suppressing the deformation of the core during the formation of the shell and the use of the base particles, the decomposition temperature of the core is preferably more than 200 ° C, more preferably more than 250 ° C, and still more preferably 300 ° C. Exceed. The decomposition temperature of the core may exceed 400 ° C., may exceed 500 ° C., may exceed 600 ° C., and may exceed 800 ° C.

  The base particles are core-shell particles. The shell is disposed on the surface of the core. The shell preferably covers the surface of the core. The shell is preferably an inorganic shell.

  The inorganic shell preferably contains 50% by weight or more of silicon atoms. In this case, the inorganic shell is an inorganic shell containing silicon atoms as a main component. Although the said inorganic shell may contain the carbon atom, even when it contains a carbon atom, if a silicon atom is a main component, it will be called an inorganic shell.

  The inorganic shell is preferably formed on the surface of the core by forming a metal alkoxide into a shell-like material by a sol-gel method and then firing the shell-like material. In the sol-gel method, it is easy to dispose a shell-like material on the surface of the core. In the case of performing the firing, in the base material particles, after the firing, the core remains without being removed by volatilization or the like. The said base particle is equipped with the said core after baking. If the core is removed by volatilization or the like after firing, the 10% K value becomes considerably low.

  As a specific method of the sol-gel method, an interfacial sol reaction is performed by coexisting an inorganic monomer such as tetraethoxysilane in a dispersion containing a core, a solvent such as water or alcohol, a surfactant, and a catalyst such as an aqueous ammonia solution. And a method in which a sol-gel reaction is performed with an inorganic monomer such as tetraethoxysilane coexisting with a solvent such as water or alcohol and an aqueous ammonia solution, and then the sol-gel reaction product is heteroaggregated in the core. In the sol-gel method, the metal alkoxide is preferably hydrolyzed and polycondensed.

  In the sol-gel method, it is preferable to use a surfactant. In the presence of a surfactant, the metal alkoxide is preferably made into a shell by a sol-gel method. The surfactant is not particularly limited. The surfactant is appropriately selected and used so as to form a good shell. Examples of the surfactant include a cationic surfactant, an anionic surfactant, and a nonionic surfactant. Among these, a cationic surfactant is preferable because a good inorganic shell can be formed.

  Examples of the cationic surfactant include quaternary ammonium salts and quaternary phosphonium salts. Specific examples of the cationic surfactant include hexadecyl ammonium bromide.

  In order to form the inorganic shell on the surface of the core, the shell-like material is preferably fired. The degree of crosslinking in the inorganic shell can be adjusted by the firing conditions. In addition, by performing the firing, the 10% K value and the 30% K value of the base material particles are more suitable as compared with the case where the firing is not performed. In particular, the 10% K value is sufficiently increased by increasing the degree of crosslinking.

  The inorganic shell is preferably formed on the surface of the core by forming a metal alkoxide into a shell-like material by a sol-gel method and then firing the shell-like material at 100 ° C. or higher (firing temperature). The firing temperature is more preferably 150 ° C. or higher, and further preferably 200 ° C. or higher. When the firing temperature is equal to or higher than the lower limit, the degree of crosslinking in the inorganic shell becomes more appropriate, and the 10% K value, 30% K value, the ratio (30% load value / 10% load value) and the ratio ( (40% load value / 10% load value) shows a more preferable value, and the base particles can be used more suitably depending on the use of the conductive particles.

  The inorganic shell is formed on the surface of the core by forming a metal alkoxide into a shell-like material by a sol-gel method, and then firing the shell-like material at a temperature lower than the decomposition temperature (firing temperature) of the organic core. It is preferable. The firing temperature is preferably 10 ° C. or more lower than the decomposition temperature of the core, and more preferably 50 ° C. or more lower than the decomposition temperature of the core. The firing temperature is preferably 500 ° C. or lower, more preferably 300 ° C. or lower, and still more preferably 200 ° C. or lower. When the firing temperature is not more than the above upper limit, thermal deterioration and deformation of the core can be suppressed, 10% K value, 30% K value, the above ratio (30% load value / 10% load value) and the above ratio (40 Base particles having a good value (% load value / 10% load value) are obtained.

  Examples of the metal alkoxide include silane alkoxide, titanium alkoxide, zirconium alkoxide, and aluminum alkoxide. From the viewpoint of forming a good inorganic shell, the metal alkoxide is preferably a silane alkoxide, a titanium alkoxide, a zirconium alkoxide or an aluminum alkoxide, more preferably a silane alkoxide, a titanium alkoxide or a zirconium alkoxide, and a silane alkoxide. More preferably. From the viewpoint of forming a good inorganic shell, the metal atom in the metal alkoxide is preferably a silicon atom, a titanium atom, a zirconium atom or an aluminum atom, more preferably a silicon atom, a titanium atom or a zirconium atom. More preferably, it is a silicon atom. As for the said metal alkoxide, only 1 type may be used and 2 or more types may be used together.

  From the viewpoint of forming a good inorganic shell, the metal alkoxide is preferably a metal alkoxide represented by the following formula (1).

M (R1) _n (OR2) _4-n (1)
In said formula (1), M is a silicon atom, a titanium atom, or a zirconium atom, R1 is a phenyl group, a C1-C30 alkyl group, a C1-C30 organic group which has a polymerizable double bond, or A C1-C30 organic group which has an epoxy group is represented, R2 represents a C1-C6 alkyl group, and n represents the integer of 0-2. When n is 2, the plurality of R1s may be the same or different. Several R2 may be the same and may differ.

  From the viewpoint of forming a good inorganic shell, the metal alkoxide is preferably a silane alkoxide represented by the following formula (1A).

Si (R1) _n (OR2) _4-n (1A)
In the above formula (1A), R1 represents a phenyl group, an alkyl group having 1 to 30 carbon atoms, an organic group having 1 to 30 carbon atoms having a polymerizable double bond, or an organic group having 1 to 30 carbon atoms having an epoxy group. R2 represents an alkyl group having 1 to 6 carbon atoms, and n represents an integer of 0 to 2. When n is 2, the plurality of R1s may be the same or different. Several R2 may be the same and may differ. In order to effectively increase the content of silicon atoms contained in the shell, n in the above formula (1A) preferably represents 0 or 1, and more preferably represents 0. When the content of silicon atoms contained in the shell is high, the effect of the present invention is more excellent.

  When R1 is an alkyl group having 1 to 30 carbon atoms, specific examples of R1 include methyl group, ethyl group, propyl group, isopropyl group, isobutyl group, n-hexyl group, cyclohexyl group, n-octyl group, And n-decyl group. This alkyl group preferably has 10 or less carbon atoms, more preferably 6 or less. The alkyl group includes a cycloalkyl group.

  Examples of the polymerizable double bond include a carbon-carbon double bond. When R1 is an organic group having 1 to 30 carbon atoms having a polymerizable double bond, specific examples of R1 include a vinyl group, an allyl group, an isopropenyl group, and a 3- (meth) acryloxyalkyl group. Etc. Examples of the (meth) acryloxyalkyl group include a (meth) acryloxymethyl group, a (meth) acryloxyethyl group, and a (meth) acryloxypropyl group. The carbon number of the organic group having 1 to 30 carbon atoms having a polymerizable double bond is preferably 2 or more, preferably 30 or less, more preferably 10 or less. The above “(meth) acryloxy” means methacryloxy or acryloxy.

  When R1 is an organic group having 1 to 30 carbon atoms having an epoxy group, specific examples of R1 include 1,2-epoxyethyl group, 1,2-epoxypropyl group, 2,3-epoxypropyl group, Examples include 3,4-epoxybutyl group, 3-glycidoxypropyl group, and 2- (3,4-epoxycyclohexyl) ethyl group. The carbon number of the C1-C30 organic group having the epoxy group is preferably 8 or less, more preferably 6 or less. In addition, the C1-C30 organic group which has the said epoxy group is group containing the oxygen atom derived from an epoxy group in addition to a carbon atom and a hydrogen atom.

  Specific examples of R2 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and an isobutyl group. In order to effectively increase the content of silicon atoms contained in the shell, R2 preferably represents a methyl group or an ethyl group.

  Specific examples of the silane alkoxide include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, isopropyltrimethoxysilane, isobutyltrimethoxysilane, cyclohexyltrimethoxy. Examples include silane, n-hexyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, phenyltrimethoxysilane, dimethyldimethoxysilane, and diisopropyldimethoxysilane. Silane alkoxides other than these may be used.

  In order to effectively increase the content of silicon atoms contained in the shell, it is preferable to use tetramethoxysilane or tetraethoxysilane as the material of the shell. In 100% by weight of the shell material, the total content of tetramethoxysilane and tetraethoxysilane is preferably 50% by weight or more (or the total amount may be sufficient). In 100% by weight of the shell, the total content of the skeleton derived from tetramethoxysilane and the skeleton derived from tetraethoxysilane is preferably 50% by weight or more (or the total amount may be sufficient).

  Specific examples of the titanium alkoxide include titanium tetramethoxide, titanium tetraethoxide, titanium tetraisopropoxide, titanium tetrabutoxide, and the like. Titanium alkoxides other than these may be used.

  Specific examples of the zirconium alkoxide include zirconium tetramethoxide, zirconium tetraethoxide, zirconium tetraisopropoxide, zirconium tetrabutoxide and the like. Other zirconium alkoxides may be used.

  The metal alkoxide preferably includes a metal alkoxide having a structure in which four oxygen atoms are directly bonded to a metal atom. The metal alkoxide preferably includes a metal alkoxide represented by the following formula (1a).

M (OR2) ₄ (1a)
In said formula (1a), M is a silicon atom, a titanium atom, or a zirconium atom, R2 represents a C1-C6 alkyl group. Several R2 may be the same and may differ.

  The metal alkoxide preferably includes a silane alkoxide having a structure in which four oxygen atoms are directly bonded to a silicon atom. In this silane alkoxide, generally, four oxygen atoms are bonded to a silicon atom by a single bond. The metal alkoxide preferably includes a silane alkoxide represented by the following formula (1Aa).

Si (OR2) ₄ (1Aa)
In said formula (1Aa), R2 represents a C1-C6 alkyl group. Several R2 may be the same and may differ.

  From the viewpoint of effectively increasing the 10% K value and effectively lowering the 30% K value, in the 100 mol% of the metal alkoxide used to form the inorganic shell, four oxygen atoms exist in the metal atom. A metal alkoxide having a structure in which is directly bonded, a metal alkoxide represented by the above formula (1a), a silane alkoxide having a structure in which four oxygen atoms are directly bonded to the silicon atom, or the above formula (1Aa) The content of each silane alkoxide represented by the formula is preferably 20 mol% or more, more preferably 40 mol% or more, still more preferably 50 mol% or more, still more preferably 55 mol% or more, and particularly preferably 60 mol%. As mentioned above, it is 100 mol% or less. The total amount of metal alkoxide used to form the inorganic shell is a metal alkoxide having a structure in which four oxygen atoms are directly bonded to the metal atom, the metal alkoxide represented by the formula (1a), the silicon atom May be a silane alkoxide having a structure in which four oxygen atoms are directly bonded to each other, or a silane alkoxide represented by the above formula (1Aa).

  From the viewpoint of effectively increasing the 10% K value and effectively decreasing the 30% K value, four oxygen atoms out of 100% of the total number of metal atoms derived from the metal alkoxide contained in the inorganic shell. Proportion of the number of metal atoms to which atoms are directly bonded The number of silicon atoms to which four -O-Si groups are directly bonded and four oxygen atoms in the four -O-Si groups are directly bonded The number ratio is preferably 20% or more, more preferably 40% or more, still more preferably 50% or more, still more preferably 55 mol% or more, and particularly preferably 60% or more.

  From the viewpoint of appropriately increasing the 10% K value and controlling the ratio (30% load value / 10% load value) and the ratio (40% load value / 10% load value) to an appropriate range. The ratio of the number of metal atoms to which four oxygen atoms are directly bonded is preferably 20% or more, more preferably 40% or more, among 100% of the total number of metal atoms contained in the inorganic shell. Preferably it is 50% or more, More preferably, it is 55 mol% or more, Most preferably, it is 60% or more. From the viewpoint of appropriately increasing the 10% K value and controlling the ratio (30% K value / 10% K value) to an appropriate range, the metal alkoxide is a silane alkoxide and contained in the inorganic shell. Of the total number of silicon atoms being 100%, four —O—Si groups are directly bonded, and four oxygen atoms in the four —O—Si groups are directly bonded. The ratio is preferably 20% or more, more preferably 40% or more, still more preferably 50% or more, still more preferably 55% or more, and particularly preferably 60% or more.

  In addition, a silicon atom in which four —O—Si groups are directly bonded and four oxygen atoms in the four —O—Si groups are directly bonded is represented by, for example, the following formula (11). It is a silicon atom in the structure. Specifically, it is a silicon atom indicated by an arrow A in the structure represented by the following formula (11X).

  The oxygen atom in the above formula (11) generally forms a siloxane bond with the adjacent silicon atom.

  The ratio of the number of silicon atoms in which four -O-Si groups are directly bonded and the four oxygen atoms in the four -O-Si groups are directly bonded (the ratio of the number of Q4 (%)). As a measuring method, for example, using an NMR spectrum analyzer, Q4 (four -O-Si groups are directly bonded and four oxygen atoms in the four -O-Si groups are directly bonded). The peak area of silicon atoms) and Q1 to Q3 (1 to 3 —O—Si groups are directly bonded, and 1 to 3 oxygen atoms in 1 to 3 —O—Si groups are directly bonded to each other. And the peak area of silicon atoms). According to this method, in the total number of 100% of silicon atoms contained in the inorganic shell, four —O—Si groups are directly bonded and four oxygen atoms in the four —O—Si groups are directly bonded. The ratio of the number of bonded silicon atoms (the ratio of the number of Q4) can be determined.

  The thickness of the shell is preferably 100 nm or more, more preferably 200 nm or more, preferably 5 μm or less, more preferably 3 μm or less. When the thickness of the shell is not less than the above lower limit and not more than the above upper limit, the 10% K value and the 30% K value show even more suitable values, and the base particles can be suitably used for the use of conductive particles. . The thickness of the shell is an average thickness per base particle. The thickness of the shell can be controlled by controlling the sol-gel method.

  In the present invention, the thickness of the shell can be determined from the difference in average value between the particle diameter of the base particle and the core particle diameter. The particle diameter of the base particle means a diameter when the base particle is a true sphere, and when the base particle is a shape other than a true sphere, it is assumed to be a true sphere corresponding to its volume. This means the diameter when For the measurement of the particle size, for example, a particle size distribution measuring machine using principles such as laser light scattering, electric resistance value change, image analysis after imaging can be used.

  The aspect ratio of the substrate particles is preferably 2 or less, more preferably 1.5 or less, and still more preferably 1.2 or less. The aspect ratio indicates a major axis / minor axis.

(Conductive particles)
The said electroconductive particle is equipped with the base material particle mentioned above and the conductive layer arrange | positioned on the surface of this base material particle.

  In FIG. 1, the electroconductive particle which concerns on the 1st Embodiment of this invention is shown with sectional drawing.

  The electroconductive particle 1 shown in FIG. 1 has the base material particle 11 and the electroconductive layer 2 arrange | positioned on the surface of the base material particle 11. FIG. The conductive layer 2 covers the surface of the base particle 11. The conductive particle 1 is a coated particle in which the surface of the base particle 11 is coated with the conductive layer 2.

  The base particle 11 includes a core 12 and a shell 13 disposed on the surface of the core 12. The shell 13 covers the surface of the core 12. The conductive layer 2 is disposed on the surface of the shell 13. The conductive layer 2 covers the surface of the shell 13.

  In FIG. 2, the electroconductive particle which concerns on the 2nd Embodiment of this invention is shown with sectional drawing.

  The conductive particle 21 shown in FIG. 2 has the base particle 11 and the conductive layer 22 arranged on the surface of the base particle 11. The conductive layer 22 includes a first conductive layer 22A that is an inner layer and a second conductive layer 22B that is an outer layer. The first conductive layer 22 </ b> A is disposed on the surface of the base particle 11. On the surface of the shell 13, the first conductive layer 22A is disposed. A second conductive layer 22B is disposed on the surface of the first conductive layer 22A.

  In FIG. 3, the electroconductive particle which concerns on the 3rd Embodiment of this invention is shown with sectional drawing.

  The conductive particles 31 shown in FIG. 3 include base material particles 11, a conductive layer 32, a plurality of core substances 33, and a plurality of insulating substances 34.

  The conductive layer 32 is disposed on the surface of the base particle 11. A conductive layer 32 is disposed on the surface of the shell 13.

  The conductive particles 31 have a plurality of protrusions 31a on the conductive surface. The conductive layer 32 has a plurality of protrusions 32a on the outer surface. Thus, the conductive particles may have protrusions on the conductive surface or may have protrusions on the outer surface of the conductive layer. A plurality of core substances 33 are arranged on the surface of the base particle 11. A plurality of core materials 33 are arranged on the surface of the shell 13. The plurality of core materials 33 are embedded in the conductive layer 32. The core substance 33 is disposed inside the protrusions 31a and 32a. The conductive layer 32 covers a plurality of core materials 33. The outer surface of the conductive layer 32 is raised by the plurality of core materials 33, and protrusions 31a and 32a are formed.

  The conductive particles 31 have an insulating material 34 disposed on the outer surface of the conductive layer 32. At least a part of the outer surface of the conductive layer 32 is covered with an insulating material 34. The insulating substance 34 is made of an insulating material and is an insulating particle. Thus, the said electroconductive particle may have the insulating substance arrange | positioned on the outer surface of a conductive layer.

  The metal for forming the conductive layer is not particularly limited. Examples of the metal include gold, silver, palladium, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, thallium, germanium, cadmium, silicon, and these. And the like. Examples of the metal include tin-doped indium oxide (ITO) and solder. Especially, since the connection resistance between electrodes can be made still lower, an alloy containing tin, nickel, palladium, copper or gold is preferable, and nickel or palladium is preferable.

  Like the conductive particles 1 and 31, the conductive layer may be formed of a single layer. Like the conductive particles 21, the conductive layer may be formed of a plurality of layers. That is, the conductive layer may have a stacked structure of two or more layers. When the conductive layer is formed of a plurality of layers, the outermost layer is preferably a gold layer, a nickel layer, a palladium layer, a copper layer, or an alloy layer containing tin and silver, and is a gold layer. Is more preferable. When the outermost layer is these preferred conductive layers, the connection resistance between the electrodes is further reduced. Moreover, when the outermost layer is a gold layer, the corrosion resistance is further enhanced.

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

  The particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 520 μm or less, more preferably 500 μm or less, still more preferably 100 μm or less, still more preferably 50 μm or less, and particularly preferably 20 μm. It is as follows. When the particle size of the conductive particles is not less than the above lower limit and not more than the above upper limit, the contact area between the conductive particles and the electrode is sufficiently large when the electrodes are connected using the conductive particles, and the conductive layer When forming the conductive particles, it becomes difficult to form aggregated conductive particles. Further, the distance between the electrodes connected via the conductive particles does not become too large, and the conductive layer is difficult to peel from the surface of the base material particles. In addition, when the particle size of the conductive particles is not less than the above lower limit and not more than the above upper limit, the conductive particles can be suitably used for a conductive material.

  The particle diameter of the conductive particles means a diameter when the conductive particles are spherical, and when the conductive particles have a shape other than a true spherical shape, it is assumed that the conductive particles have a true sphere corresponding to the volume. Means the diameter.

  The thickness of the conductive layer is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 10 μm or less, more preferably 1 μm or less, and still more preferably 0.3 μm or less. The thickness of the conductive layer is the thickness of the entire conductive layer when the conductive layer is a multilayer. When the thickness of the conductive layer is not less than the above lower limit and not more than the above upper limit, sufficient conductivity is obtained, and the conductive particles do not become too hard, and the conductive particles are sufficiently deformed when connecting the electrodes. .

  When the conductive layer is formed of a plurality of layers, the thickness of the outermost conductive layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, preferably 0.5 μm or less, more preferably 0. .1 μm or less. When the thickness of the outermost conductive layer is not less than the above lower limit and not more than the above upper limit, the coating with the outermost conductive layer becomes uniform, the corrosion resistance becomes sufficiently high, and the connection resistance between the electrodes is further increased. Lower. Further, when the outermost layer is a gold layer, the thinner the gold layer, the lower the cost.

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

  The conductive particles may have protrusions on the conductive surface. The conductive particles may have protrusions on the outer surface of the conductive layer. It is preferable that there are a plurality of the protrusions. An oxide film is often formed on the surface of the conductive layer and the surface of the electrode connected by the conductive particles. When conductive particles having protrusions are used, the oxide film is effectively eliminated by the protrusions by placing the conductive particles between the electrodes and pressing them. For this reason, an electrode and the conductive layer of electroconductive particle can be contacted still more reliably, and the connection resistance between electrodes can be made low. Furthermore, when the conductive particles are provided with an insulating material on the surface, or when the conductive particles are dispersed in a binder resin and used as a conductive material, the conductive particles and the electrodes are separated by protrusions of the conductive particles. Insulating substances or binder resins in between can be effectively eliminated. For this reason, the conduction | electrical_connection reliability between electrodes can be improved.

  As a method of forming protrusions on the surface of the conductive particles, a method of forming a conductive layer by electroless plating after attaching a core substance to the surface of the base particles, and electroless plating on the surface of the base particles Examples include a method of forming a conductive layer by, attaching a core substance, and further forming a conductive layer by electroless plating. In addition, the core material may not be used to form the protrusion.

  The conductive particles may include an insulating substance disposed on the outer surface of the conductive layer. In this case, when the conductive particles are used for connection between the electrodes, a short circuit between adjacent electrodes can be prevented. Specifically, when a plurality of conductive particles are in contact with each other, an insulating material is present between the plurality of electrodes, so that it is possible to prevent a short circuit between electrodes adjacent in the lateral direction instead of between the upper and lower electrodes. In addition, the insulating substance between the conductive layer of an electroconductive particle and an electrode can be easily excluded by pressurizing electroconductive particle with two electrodes in the case of the connection between electrodes. When the conductive particles have protrusions on the surface of the conductive layer, the insulating substance between the conductive layer of the conductive particles and the electrode can be more easily eliminated. The insulating substance is preferably an insulating resin layer or insulating particles, and more preferably insulating particles. The insulating particles are preferably insulating resin particles.

(Conductive material)
The conductive material includes the conductive particles described above and a binder resin. The conductive particles are preferably dispersed in a binder resin and used as a conductive material. The conductive material is preferably an anisotropic conductive material. The conductive material is preferably used for electrical connection of electrodes. The conductive material is preferably a circuit connection material.

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

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

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

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

  The conductive material can be used as a conductive paste and a conductive film. When the conductive material according to the present invention is a conductive film, a film that does not include conductive particles may be laminated on a conductive film that includes conductive particles. The conductive paste is preferably an anisotropic conductive paste. The conductive film is preferably an anisotropic conductive film.

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

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

(Connection structure)
A connection structure can be obtained by connecting the connection target members using the conductive particles described above or using a conductive material including the conductive particles described above and a binder resin.

  The connection structure includes a first connection target member, a second connection target member, and a connection portion connecting the first connection target member and the second connection target member, and the connection portion. Is preferably formed of the above-described conductive particles, or a connection structure formed of a conductive material containing the above-described conductive particles and a binder resin. When the conductive particles are used alone, the connection part itself is the conductive particles. That is, the first and second connection target members are connected by the conductive particles. The conductive material used for obtaining the connection structure is preferably an anisotropic conductive material.

  The first connection target member preferably has a first electrode on the surface. The second connection target member preferably has a second electrode on the surface. It is preferable that the first electrode and the second electrode are electrically connected by the conductive particles.

  FIG. 4 is a front sectional view schematically showing a connection structure using the conductive particles 1 shown in FIG.

  The connection structure 51 shown in FIG. 4 is a connection that connects the first connection target member 52, the second connection target member 53, and the first connection target member 52 and the second connection target member 53. Part 54. The connection part 54 is formed of a conductive material containing the conductive particles 1 and a binder resin. In FIG. 4, the conductive particles 1 are schematically shown for convenience of illustration. Instead of the conductive particles 1, other conductive particles such as the conductive particles 21 and 31 may be used.

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

The manufacturing method of the connection structure is not particularly limited. As an example of a method of manufacturing a connection structure, a method of placing the conductive material between a first connection target member and a second connection target member to obtain a laminate, and then heating and pressurizing the laminate Etc. The pressure of the said pressurization is about 9.8 * 10 < ⁴ > -4.9 * 10 < ⁶ > Pa. The temperature of the said heating is about 120-220 degreeC. The pressure of the pressurization for connecting the electrode of the flexible printed board, the electrode arranged on the resin film, and the electrode of the touch panel is about 9.8 × 10 ^{4 to} 1.0 × 10 ⁶ Pa.

  Specific examples of the connection target member include electronic components such as semiconductor chips, capacitors, and diodes, and electronic components such as printed boards, flexible printed boards, glass epoxy boards, and glass boards. 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 on the connection target member in a paste-like state.

  The conductive particles and the conductive material are also suitably used for touch panels. Therefore, the connection target member is preferably a flexible printed circuit board or a connection target member in which an electrode is disposed on the surface of a resin film. The connection target member is preferably a flexible printed board, and is preferably a connection target member in which an electrode is disposed on the surface of the resin film. The flexible printed board generally has electrodes on the surface.

  In particular, in the present invention, the initial hardness of the base particles is designed in an appropriate range in order to suppress damage to the connection target member such as the substrate of the conductive particles. For this reason, in the present invention, when the surface of the electrode is a metal that is easily oxidized such as titanium or molybdenum, a glass substrate (thickness of about 0.2 mm) having a relatively small thickness is connected to a semiconductor chip, or flexible. When connecting a printed circuit board and a semiconductor chip, a great effect is exhibited.

  The combination of the first and second connection target members is preferably a combination of a glass substrate or a flexible printed circuit board and a semiconductor chip, preferably a combination of a glass substrate and a semiconductor chip, A combination with a semiconductor chip is also preferable. In this case, the first connection target member may be a glass substrate or a flexible printed board, and the second connection target member may be a glass substrate or a flexible printed board. The thickness of the glass substrate is preferably 0.05 mm or more and less than 0.5 mm.

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

  At least one of the first and second electrodes is preferably a titanium electrode or a molybdenum electrode, and both of the first and second electrodes are preferably a titanium electrode or a molybdenum electrode. At least one of the materials constituting the surfaces of the first and second electrodes preferably contains titanium or molybdenum, and both the materials constituting the surfaces of the first and second electrodes are titanium or More preferably, it contains molybdenum.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited only to the following examples.

Example 1
(1) Production of base particles Production of core)
950 parts by weight of 1,4-butanediol diacrylate and 50 parts by weight of ethylene glycol dimethacrylate were mixed to obtain a mixed solution. 20 parts by weight of benzoyl peroxide was added to the obtained mixed solution and stirred until it was uniformly dissolved to obtain a monomer mixed solution. 4000 parts by weight of a 2% by weight aqueous solution in which polyvinyl alcohol having a molecular weight of about 1700 was dissolved in pure water was placed in a reaction kettle. Into this, the obtained monomer mixture was put and stirred for 4 hours to adjust the particle size so that the monomer droplets had a predetermined particle size. Thereafter, the reaction was performed in a nitrogen atmosphere at 85 ° C. for 9 hours, and the polymerization reaction of the monomer droplets was performed to obtain particles. The obtained particles were washed several times with hot water, and then classified to recover polymer particles (organic cores) having several different particle sizes.

  In Example 1, among the polymer particles recovered by the classification operation, polymer particles (organic core) having a particle size of 2.49 μm were prepared.

Preparation of core-shell particles)
30 parts by weight of the obtained polymer particles (organic core), 12 parts by weight of hexadecylammonium bromide as a surfactant, 24 parts by weight of a 25% by weight aqueous ammonia solution, 540 parts by weight of isopropyl alcohol and 60 parts of pure water. It put in the weight part and mixed, and the dispersion liquid of the polymer particle was obtained. To this dispersion, 140 parts by weight of tetraethoxysilane was added, and a condensation reaction by a sol-gel reaction was performed. A condensate of tetraethoxysilane was deposited on the surface of the polymer particles to form a shell, thereby obtaining particles. The obtained particles were washed several times with ethanol and dried to obtain core-shell particles (base material particles). The obtained core-shell particles had a particle size of 3.01 μm. From the core particle size and the core-shell particle size, the thickness of the shell was calculated to be 0.26 μm.

(2) Production of conductive particles The obtained base particles were washed and dried. Then, the nickel layer was formed in the surface of the obtained base material particle | grains by the electroless-plating method, and the electroconductive particle was produced. The nickel layer had a thickness of 0.1 μm.

(Example 2)
Among the polymer particles recovered by the classification operation in Example 1, polymer particles (organic core) having a particle size of 2.25 μm were prepared. Core-shell particles and conductive particles were obtained in the same manner as in Example 1 except that the obtained polymer particles were used and that the amount of tetraethoxysilane added was changed to 310 parts by weight when producing the core-shell particles. Got.

(Example 3)
The base material particles obtained in Example 1 were heat-treated at 200 ° C. for 30 minutes in a state where nitrogen was filled in an electric furnace. Thereafter, conductive particles were produced in the same manner as in Example 1.

(Example 4)
(1) Palladium adhesion process The base material particle obtained in Example 1 was prepared. The obtained substrate particles were etched and washed with water. Next, the base particles were added to 100 mL of a palladium-catalyzed solution containing 8% by weight of a palladium catalyst and stirred. Then, it filtered and wash | cleaned. Substrate particles were added to a 0.5 wt% dimethylamine borane solution at pH 6 to obtain substrate particles to which palladium was attached.

(2) Core substance adhesion process The base material particle | grains to which palladium was adhered were stirred and dispersed for 3 minutes in 300 mL of ion-exchange water, and the dispersion liquid was obtained. Next, 1 g of metallic nickel particle slurry (average particle size 100 nm) was added to the dispersion over 3 minutes to obtain base particles to which the core material was adhered.

(3) Electroless nickel plating step In the same manner as in Example 1, a nickel layer was formed on the surface of the substrate particles to produce conductive particles. The nickel layer had a thickness of 0.1 μm.

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

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

  10 g of the conductive particles obtained in Example 1 were dispersed in 500 mL of ion exchange water, 4 g of an aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 6 hours. After filtration through a 3 μm mesh filter, the particles were further washed with methanol and dried to obtain conductive particles having insulating particles attached thereto.

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

(Example 6)
Among the polymer particles recovered by the classification operation in Example 1, polymer particles (organic core) having a particle size of 2.25 μm were prepared. Other than using the obtained polymer particles and changing the amount of methanol added to 540 parts by weight of acetonitrile and 310 parts by weight of tetraethoxysilane when preparing the core-shell particles. Produced core-shell particles and conductive particles in the same manner as in Example 1.

(Example 7)
Among the polymer particles classified and recovered in Example 1, polymer particles (organic core) having a particle diameter of 2.75 μm were prepared. Except that the obtained polymer particles were used and that the core-shell particles were produced, that 540 parts by weight of methanol was changed to 540 parts by weight of acetonitrile, and the addition amount of tetraethoxysilane was changed to 50 parts by weight. In the same manner as in Example 1, core-shell particles and conductive particles were obtained.

(Comparative Example 1)
Among the polymer particles recovered in the classification operation in Example 1, polymer particles having a particle size of 3.02 μm were prepared. Using the obtained polymer particles as base particles, conductive particles were obtained in the same manner as in Example 1.

(Comparative Example 2)
In preparing the core, 950 parts by weight of 1,4-butanediol diacrylate and 50 parts by weight of ethylene glycol dimethacrylate were changed to 600 parts by weight of divinylbenzene (purity 96% by weight) and 400 parts by weight of isobornyl acrylate. Except that, particles were obtained in the same manner as in Example 1. After the obtained particles were washed several times with hot water, classification operation was performed to collect several kinds of polymer particles having different particle sizes.

  In Comparative Example 2, polymer particles having a particle size of 3.00 μm were prepared from the polymer particles recovered by the classification operation. Using the obtained polymer particles as base particles, conductive particles were obtained in the same manner as in Example 1.

(Comparative Example 3)
In preparing the core, 950 parts by weight of 1,4-butanediol diacrylate and 50 parts by weight of ethylene glycol dimethacrylate were changed to 1000 parts by weight of divinylbenzene (purity 96% by weight), and addition of benzoyl peroxide. Particles were obtained in the same manner as in Example 1 except that the amount was changed to 40 parts by weight. After the obtained particles were washed several times with hot water, classification operation was performed to collect several kinds of polymer particles having different particle sizes.

  In Comparative Example 3, polymer particles having a particle size of 3.01 μm were prepared from the polymer particles recovered by the classification operation. Using the obtained polymer particles as base particles, conductive particles were obtained in the same manner as in Example 1.

(Comparative Example 4)
In preparing the core, 950 parts by weight of 1,4-butanediol diacrylate and 50 parts by weight of ethylene glycol dimethacrylate were changed to 800 parts by weight of divinylbenzene (purity 96% by weight) and 200 parts by weight of acrylonitrile, and Particles were obtained in the same manner as in Example 1 except that the amount of benzoyl peroxide added was changed to 40 parts by weight. After the obtained particles were washed several times with hot water, classification operation was performed to collect several kinds of polymer particles having different particle sizes.

  In Comparative Example 4, polymer particles having a particle size of 3.00 μm were prepared from the polymer particles recovered by the classification operation. Using the obtained polymer particles as base particles, conductive particles were obtained in the same manner as in Example 1.

(Comparative Example 5)
Among the polymer particles recovered in the classification operation in Example 1, polymer particles having a particle size of 3.01 μm were prepared. When producing core-shell particles using the obtained polymer particles, core-shell particles and conductive particles are obtained in the same manner as in Example 1 except that the amount of tetraethoxysilane added is changed to 10 parts by weight. It was.

(Evaluation)
(1) Particle size of base particle, core particle size and shell thickness About the obtained base particle, about 10,000 particle sizes were measured using a particle size distribution measuring device (“Multizer 3” manufactured by Beckman Coulter, Inc.). The average particle size and standard deviation were measured. The particle diameter of the core used for producing the base particle was measured by the same method. The thickness of the shell was determined from the difference between the particle size of the substrate particles and the particle size of the core.

(2) Compressive elastic modulus (10% K value and 30% K value) of substrate particles, and 10% load value, 30% load value, and 40% load value The compression elastic modulus (10 % K value and 30% K value), 10% load value, 30% load value and 40% load value under the condition of 23 ° C., by the method described above, the micro compression tester (Fischer Scope H manufactured by Fischer) -100 ").

(3) Compression recovery rate of substrate particles The compression recovery rate of the obtained substrate particles was measured by the method described above using a micro compression tester (Fischer Scope H-100 manufactured by Fischer).

(4) Fracture strain of base material particle Using a micro compression tester (“Fischerscope H-100” manufactured by Fischer), fracture strain was measured by the method described above at 23 ° C.

(5) Connection resistance Fabrication of connection structure:
10 parts by weight of bisphenol A type epoxy resin (“Epicoat 1009” manufactured by Mitsubishi Chemical Corporation), 40 parts by weight of acrylic rubber (weight average molecular weight of about 800,000), 200 parts by weight of methyl ethyl ketone, and a microcapsule type curing agent (Asahi Kasei E-material) 50 parts by weight of “HX3941HP” manufactured by S. Co., Ltd. and 2 parts by weight of silane coupling agent (“SH6040” manufactured by Toray Dow Corning Silicone Co., Ltd.) are added, and conductive particles are added to a content of 3% by weight. And dispersed to obtain a resin composition.

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

  The obtained anisotropic conductive film was cut into a size of 5 mm × 5 mm. A PET substrate (width 3 cm, length 3 cm) provided with an ITO electrode (height 0.1 μm, L / S = 20 μm / 20 μm) having a lead wire for resistance measurement on one side of the cut anisotropic conductive film. ) On the ITO electrode side. Subsequently, the two-layer flexible printed circuit board (width 2cm, length 1cm) provided with the same gold electrode was bonded after aligning so that electrodes might overlap. A laminate of the PET substrate and the two-layer flexible printed circuit board was thermocompression bonded under pressure bonding conditions of 10 N, 180 ° C., and 20 seconds to obtain a connection structure. In addition, the two-layer flexible printed board by which the copper electrode was formed in the polyimide film and the copper electrode surface was Au-plated was used.

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

[Evaluation criteria for connection resistance]
◯: Connection resistance is 3.0Ω or less ○: Connection resistance exceeds 3.0Ω, 4.0Ω or less △: Connection resistance exceeds 4.0Ω, 5.0Ω or less ×: Connection resistance exceeds 5.0Ω

(6) Presence / absence of cracks in electrodes In the connection structure obtained in the above (5) evaluation of connection resistance, it was observed whether or not cracks occurred in 100 electrodes.

[Presence of cracks in the electrode]
◯: There is no number of cracks generated in 100 electrodes. ○: The number of cracks generated in 100 electrodes is 2 or less. △: Cracks are generated in 100 electrodes. The number is 3 to 5 ×: out of 100 electrodes, the number of cracks is 6 to 10 XX: out of 100 electrodes, the number of cracks is 11 or more

(7) Connection reliability under high-temperature and high-humidity conditions 100 connection structures obtained by the above (5) evaluation of connection resistance were left at 85 ° C. and 85% RH for 100 hours. About 100 connection structures after a test, it was evaluated whether the electrical connection defect between the upper and lower electrodes had arisen.
◯: Among 100 connection structures, the number of defective conduction is 1 or less. ○: Among 100 connection structures, the number of defective conduction is 2-5. Δ: Of the 100 connection structures, the number of defective conduction is 6 to 10. *: Of 100 connection structures, the number of defective conduction is 11 or more.

  The results are shown in Table 1 below. The aspect ratio of the base particles obtained in Examples 1 to 3, 6, and 7 was 1.2 or less. The connection resistance evaluation results in Examples 2 to 4 and 6 are all “◯◯”, but the connection resistance value in Example 4 is lower than the connection resistance values in Examples 2 to 3 and 6. It was. Protrusions are thought to have affected.

DESCRIPTION OF SYMBOLS 1 ... Conductive particle 2 ... Conductive layer 11 ... Base particle 12 ... Core 13 ... Shell 21 ... Conductive particle 22 ... Conductive layer 22A ... 1st conductive layer 22B ... 2nd conductive layer 31 ... Conductive particle 31a ... Projection 32 ... Conductive layer 32a ... Protrusion 33 ... Core material 34 ... Insulating material 51 ... Connection structure 52 ... First connection object member 52a ... First electrode 53 ... Second connection object member 53a ... Second electrode 54. Connection part

Claims (10)

A conductive layer is formed on the surface, and is a base particle used for obtaining conductive particles having the conductive layer,
Core-shell particles comprising a core and a shell disposed on a surface of the core;
The core is an organic core, the shell is an inorganic shell,
The compression recovery rate when compressed and deformed by 30% is 50% or more,
10% compressed compressive elastic modulus of when the 3000N / mm ² or more and less than 6000 N / mm ^2,
The base material particle whose ratio with respect to the load value when compressed by 10% of the load value when compressed by 30% is 3 or less. The base particle according to claim 1, wherein the shell has a thickness of 100 nm or more and 5 μm or less. The base particle according to claim 1 or 2 , wherein the compression elastic modulus when compressed by 30% is 3000 N / mm ² or less. The base particle according to any one of claims 1 to 3 , wherein a ratio of a load value obtained by compressing 40% to a load value obtained by compressing 10% is 6 or less. The base material particle according to any one of claims 1 to 4 , wherein the fracture strain is 10% or more and 30% or less. Base material particles according to any one of claims 1 to 5 ,
Electroconductive particle provided with the conductive layer arrange | positioned on the surface of the said base material particle. The conductive particle according to claim 6 , further comprising an insulating material disposed on an outer surface of the conductive layer. The electroconductive particle of Claim 6 or 7 which has a processus | protrusion on the outer surface of the said conductive layer. Containing conductive particles and a binder resin,
A conductive material, wherein the conductive particles comprise the base particles according to any one of claims 1 to 5 and a conductive layer disposed on a surface of the base particles. A first connection object member having a first electrode on its surface;
A second connection target member having a second electrode on its surface;
A connection portion connecting the first connection target member and the second connection target member;
The connecting portion is formed of conductive particles or formed of a conductive material containing the conductive particles and a binder resin;
The conductive particles comprise the base particles according to any one of claims 1 to 5 and a conductive layer disposed on the surface of the base particles,
A connection structure in which the first electrode and the second electrode are electrically connected by the conductive particles.

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