JP2013030479A - Conductive particle with insulative particle, anisotropic conductive material, and connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a conductive particle with insulative particles, capable of enhancing conduction reliability and insulation reliability when used for connection between electrodes; and an anisotropic conductive material.SOLUTION: A conductive particle 1 with insulative particles according to the present invention includes: a conductive particle 2 having a conductive part 12 at least on a surface thereof; and a plurality of insulative particles 3 attached on the surface of the conductive particle 2. A specific gravity ratio of a specific gravity of the conductive particle 1 with insulative particles to a specific gravity of the conductive particle 2 is less than 0.97. The specific gravity of the conductive particle 2 is 2.0 or more and 3.5 or less. An anisotropic conductive material according to the present invention includes the conductive particle 1 with insulative particles and a binder resin.

Description

  The present invention relates to conductive particles with insulating particles in which a plurality of insulating particles are attached to the surface of the conductive particles, for example, conductive particles with insulating particles that can be used for electrical connection between electrodes. The present invention also relates to an anisotropic conductive material and a connection structure using the conductive particles with insulating particles.

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

  As an example of the conductive particles, the following Patent Documents 1 and 2 disclose conductive particles with insulating particles including conductive particles and insulating particles covering the surface of the conductive particles. ing.

In the conductive particles with insulating particles described in Patent Document 1, the specific gravity of the conductive particles with insulating particles is 97/100 to 99/100 of the specific gravity of the conductive particles. In the conductive particles with insulating particles described in Patent Document 2, the insulating particles are bonded to the conductive particles so that they can be removed by an external pressure of 1 to ³ kg / cm ² G.

  Patent Document 3 below discloses conductive particles with insulating particles having conductive particles and insulating particles fixed to the surface of the conductive particles and having adhesive properties. The insulating particles include hard particles and a polymer resin layer covering the surfaces of the hard particles. Here, a physical / mechanical hybridization method is used as an immobilization method in order to immobilize the insulating particles on the surface of the conductive particles.

Japanese Patent No. 4386148 Japanese Patent No. 28958872 Special table 2007-537570 gazette

  When an anisotropic conductive material is produced by mixing conventional conductive particles with insulating particles as described in Patent Documents 1 to 3 and a binder resin, the dispersibility of the conductive particles with insulating particles may be low. .

  Furthermore, the conductive particles with insulating particles may settle in the anisotropic conductive material. For this reason, the anisotropic conductive material cannot be applied uniformly during the conductive connection, and the conductive particles may not be disposed between the upper and lower electrodes. Further, the agglomerated conductive particles may cause a short circuit between electrodes adjacent in the lateral direction. That is, the conduction reliability between the upper and lower electrodes to be connected and the insulation reliability between the laterally adjacent electrodes that should not be connected may be low.

  Furthermore, in the conventional conductive particles with insulating particles, the insulating particles are easily detached from the surface of the conductive particles. For example, when the conductive particles with insulating particles are dispersed in the binder resin, the insulating particles may be easily detached from the surface of the conductive particles.

  In particular, as described in Patent Document 3, when a physical / mechanical hybridization method is used to immobilize the insulating particles on the surface of the conductive particles, the insulating particles are made of conductive particles. Easily detached from the surface. Furthermore, when the physical / mechanical hybridization method is used, the polymer resin layer of the insulating particles adheres to a portion other than the portion where the insulating particles are attached on the surface of the conductive particles. There is also a problem that the conductivity is impaired after the connection between the electrodes.

  Further, in the conventional conductive particles with insulating particles, at least a part of the conductive layer is exposed. For this reason, rust tends to be generated on the surface of the conductive layer by a corrosive gas in the atmosphere or a corrosive substance in the anisotropic conductive material. For this reason, high conductivity may not be sufficiently maintained over a long period of time. In addition, when the electrodes are connected using conductive particles with insulating particles in which the conductive layer has rusted, the electrodes may not be electrically connected reliably or the connection resistance between the electrodes may increase. is there.

  An object of the present invention is to provide conductive particles with insulating particles that can improve conduction reliability and insulation reliability when used for connection between electrodes, and anisotropic using the conductive particles with insulating particles. Conductive material and connection structure.

  The limited object of the present invention is that the insulating particles are difficult to unintentionally detach from the surface of the conductive particles, and therefore, when used for the connection between the electrodes, the insulating particles can be improved. An object is to provide conductive particles, and anisotropic conductive materials and connection structures using the conductive particles with insulating particles.

  A further limited object of the present invention is that the conductive particles are less likely to rust, can maintain high conductivity over a long period of time, and therefore, when used for connection between electrodes, insulating particles that can improve conduction reliability. It is to provide an attached conductive particle, and an anisotropic conductive material and a connection structure using the conductive particle with an insulating particle.

  According to a wide aspect of the present invention, a conductive particle having at least a conductive portion on the surface and a plurality of insulating particles attached to the surface of the conductive particle, the specific gravity of the conductive particle with insulating particles There are provided conductive particles with insulating particles, wherein the specific gravity ratio of the conductive particles to the specific gravity is less than 0.97, and the specific gravity of the conductive particles is 2.0 or more and 3.5 or less.

  In a specific aspect of the conductive particles with insulating particles according to the present invention, the specific gravity ratio of the specific gravity of the conductive particles with insulating particles to the specific gravity of the conductive particles is less than 0.95.

  On the specific situation with the electroconductive particle with the insulating particle which concerns on this invention, the coverage which is an area of the part coat | covered with the said insulating particle which occupies for the whole surface area of the said electroconductive particle is 40% or more.

  In another specific aspect of the conductive particles with insulating particles according to the present invention, the coverage, which is the area of the portion covered with the insulating particles in the entire surface area of the conductive particles, is 60% or more. is there.

  In still another specific aspect of the conductive particles with insulating particles according to the present invention, a conductive particle-containing liquid with insulating particles obtained by adding 3 parts by weight of conductive particles with insulating particles to 100 parts by weight of ethanol is 20 When the ultrasonic treatment is performed for 5 minutes at a temperature of 40 ° C. and 40 kHz, the residual ratio of the insulating particles obtained by the following formula (1) is 60% or more and 95% or less.

  Residual ratio of insulating particles (%) = (coverage ratio after sonication / coverage ratio before sonication) × 100 (1)

  In another specific aspect of the conductive particles with insulating particles according to the present invention, the specific gravity of the insulating particles is 1.0 or more and 2.0 or less.

  In another specific aspect of the conductive particle with insulating particles according to the present invention, a coating film covering the surface of the conductive particle is further provided.

  In still another specific aspect of the conductive particles with insulating particles according to the present invention, the coating covers the surface of the conductive particles and the surface of the insulating particles.

  In another specific aspect of the conductive particles with insulating particles according to the present invention, the coating is formed of a compound having an alkyl group having 6 to 22 carbon atoms.

  The conductive particles with insulating particles according to the present invention are preferably conductive particles with insulating particles used in a paste-like anisotropic conductive paste.

  In another specific aspect of the conductive particle with insulating particles according to the present invention, the conductive particle has a base particle and a conductive layer disposed on the surface of the base particle.

  The anisotropic conductive material according to the present invention includes the above-described conductive particles with insulating particles and a binder resin. The anisotropic conductive material according to the present invention is preferably a paste-like anisotropic conductive paste.

  A connection structure according to the present invention includes a first connection target member, a second connection target member, and a connection portion that connects the first and second connection target members. The conductive particles with insulating particles are formed by the above-described conductive particles, or the conductive particles with insulating particles and the anisotropic conductive material containing the binder resin.

  In the conductive particles with insulating particles according to the present invention, a plurality of insulating particles are attached to the surface of the conductive particles having at least a conductive portion on the surface, and the specific conductivity of the conductive particles with insulating particles is the same. The specific gravity ratio with respect to the specific gravity of the conductive particles is less than 0.97, and the specific gravity of the conductive particles is 2.0 or more and 3.5 or less. Therefore, when used for connection between electrodes, conduction reliability and insulation Reliability can be increased.

FIG. 1 is a cross-sectional view showing conductive particles with insulating particles according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing conductive particles with insulating particles according to the second embodiment of the present invention. FIG. 3 is a cross-sectional view showing conductive particles with insulating particles according to the third embodiment of the present invention. FIG. 4 is a sectional view showing conductive particles with insulating particles according to the fourth embodiment of the present invention. FIG. 5 is a front cross-sectional view schematically showing a connection structure using conductive particles with insulating particles according to the first embodiment of the present invention. FIG. 6 is a schematic diagram for explaining a method for evaluating the coverage. FIG. 7 is a cross-sectional view showing a conventional conductive particle with insulating particles using a hybridization method.

  Details of the present invention will be described below.

  The conductive particles with insulating particles according to the present invention include conductive particles having a conductive portion on at least a surface, and a plurality of insulating particles attached to the surface of the conductive particles. The specific gravity ratio (A / B) of the specific gravity A of the conductive particles with insulating particles according to the present invention to the specific gravity B of the conductive particles is less than 0.97. The specific gravity B of the conductive particles is 2.0 or more and 3.5 or less.

  By adopting the above configuration in the conductive particles with insulating particles according to the present invention, the dispersibility of the conductive particles in the anisotropic conductive material is increased. In particular, in a paste-like anisotropic conductive material, the sedimentation of conductive particles can be remarkably suppressed. Moreover, a uniform anisotropic conductive adhesive layer can be obtained by suppressing sedimentation of conductive particles. For this reason, an anisotropic conductive material can be uniformly applied or arrange | positioned on a connection object member, and electroconductive particle can be arrange | positioned more reliably between upper and lower electrodes. Further, the agglomerated conductive particles make it difficult for the electrodes adjacent in the lateral direction that should not be connected to be connected to each other, and it is possible to suppress a short circuit between the adjacent electrodes. For this reason, the conduction | electrical_connection reliability between the upper and lower electrodes which should be connected, and the insulation reliability between the electrodes adjacent to the horizontal direction which should not be connected can be improved.

  From the viewpoint of further improving the conduction reliability and the insulation reliability, the specific gravity ratio (A / B) is preferably 0.5 or more, more preferably 0.8 or more, and preferably less than 0.95. From the viewpoint of further improving the conduction reliability and the insulation reliability between the electrodes, the specific gravity B of the conductive particles is preferably 2.5 or more, more preferably 2.7 or more, and preferably 3.0 or less.

  From the viewpoint of further improving the conduction reliability and the insulation reliability, the specific gravity C of the insulating particles is preferably 1.0 or more, preferably 2.0 or less, more preferably 1.3 or less. From the viewpoint of further improving the conduction reliability and the insulation reliability, the specific gravity D of the binder resin used in combination with the conductive particles with insulating particles is preferably 0.9 or more, more preferably 1.0 or more, preferably 2.0 or less, more preferably 1.3 or less.

  The coverage, which is the area of the portion covered with the insulating particles in the entire surface area of the conductive particles, is preferably 40% or more, more preferably more than 50%, and still more preferably 60% or more. When the coverage is equal to or higher than the lower limit, adjacent conductive particles are more difficult to contact. The coverage is preferably 95% or less, more preferably 90% or less, still more preferably 80% or less, and particularly preferably 70% or less. If the coverage is less than or equal to the above upper limit, the insulating particles can be sufficiently eliminated without applying heat and pressure more than necessary when the electrodes are connected.

  The coverage, which is the area of the portion covered with the insulating particles in the entire surface area of the conductive particles, is preferably 60% or more and 95% or less. In this case, it can suppress more effectively that several electroconductive particle in several electroconductive particle with an insulating particle contacts. In particular, when electrically connecting electrodes using an anisotropic conductive material containing conductive particles with insulating particles and a binder resin, it is even more effective to prevent contact between multiple conductive particles. it can. Further, when the electrodes are electrically connected using the paste-like anisotropic conductive material, the contact of the plurality of conductive particles can be further effectively suppressed. For this reason, it is more difficult to connect the electrodes adjacent to each other in the lateral direction that should not be connected, and the occurrence of a short circuit between the adjacent electrodes can be further suppressed. On the other hand, when the coverage is 95% or less, the insulating particles in the conductive particles with insulating particles can be effectively excluded from between the electrode and the conductive particles at the time of pressure bonding. For this reason, the conduction | electrical_connection reliability between the upper and lower electrodes which should be connected can be improved considerably. When the conductive particles with insulating particles having a coverage of 60% or more and 95% or less are used, the viscosity of the anisotropic conductive material at 25 ° C. and 2.5 rpm exceeds 200 Pa · s, and 1000 Pa. -When it is below s, the effect which improves conduction | electrical_connection reliability and insulation reliability is acquired notably.

  From the viewpoint of further enhancing the conduction reliability and insulation reliability between the electrodes, the coverage is more preferably more than 70%, and preferably 90% or less. When the coverage is 90% or less, the insulating particles can be sufficiently removed without applying heat and pressure more than necessary when the electrodes are connected.

  From the viewpoint of further suppressing unintentional detachment of insulating particles from the surface of the conductive particles, with insulating particles obtained by adding 3 parts by weight of conductive particles with insulating particles to 100 parts by weight of ethanol When the conductive particle-containing liquid is subjected to ultrasonic treatment for 5 minutes at 20 ° C. and 40 kHz, the residual ratio of the insulating particles obtained by the following formula (1) is preferably 50% or more, more preferably 60% or more, More preferably, it is 70% or more, preferably 95% or less. When the residual ratio of the insulating particles is equal to or more than the lower limit, the insulating particles are more difficult to be detached from the surface of the conductive particles when the conductive particles with the insulating particles are added to the binder resin and kneaded. Become. As a result, when the electrodes are connected using the conductive particles with insulating particles, a short circuit is more unlikely to occur between adjacent electrodes that should not be connected. When the residual ratio of the insulating particles is equal to or lower than the above upper limit, it is possible to sufficiently ensure the conductivity between the upper and lower electrodes to be connected. The coverage may exceed 45%, may exceed 50%, may exceed 55%, and may exceed 60%.

  Specifically, the “residual ratio of insulating particles” is determined as follows.

  Before the following ultrasonic treatment, 100 conductive particles with insulating particles were observed by observation with a scanning electron microscope (SEM), and the coverage X1 (%) of the conductive particles in the conductive particles with insulating particles was observed. (Also referred to as adhesion rate X1 (%)) is obtained. The coverage X1 is the area (projected area) of the portion covered with the insulating particles in the entire surface area of the conductive particles.

  Specifically, as shown in FIG. 6, when the conductive particles A with insulating particles are observed from one direction with a scanning electron microscope (SEM), the coverage is as follows. One insulating particle B1 present in a circle on the outer surface (outer peripheral edge) of the conductive part, insulating property present on the circumference of the outer surface (outer peripheral edge) of the conductive part of the conductive particle A with insulating particles The number of particles B2 is counted as 0.5, and is represented by the ratio of the projected area of the insulating particles to the projected area of the conductive particles A with insulating particles.

  That is, the said coverage is represented by following formula (2).

  Coverage (%) = (((number of insulating particles in circle) × 1 + (number of insulating particles on the circumference) × 0.5) × projection area of insulating particles) / (with insulating particles) Projected area of conductive particles)) × 100 (2)

  Next, 3 parts by weight of conductive particles with insulating particles are added to 100 parts by weight of ethanol to obtain a conductive particle-containing liquid with insulating particles. This conductive particle-containing liquid with insulating particles is subjected to ultrasonic treatment while being stirred for 5 minutes at 20 ° C. and 40 kHz with an ultrasonic cleaner. After the ultrasonic treatment, 100 conductive particles with insulating particles are observed by observation with an SEM, and the portion of the conductive particles with insulating particles covered by the insulating particles occupying the entire surface area of the conductive particles. The area coverage ratio X2 (%) (also referred to as adhesion rate X2 (%)) is obtained. The residual rate of the insulating particles is a value represented by the following formula (1) from the coverage X1 and the coverage X2.

  Residual rate of insulating particles (%) = (coverage ratio X2 after ultrasonic treatment / coverage ratio X1 before ultrasonic treatment) × 100 Formula (1)

  In the conductive particles with insulating particles according to the present invention, the insulating particles preferably have an insulating particle body and a layer covering at least a part of the surface of the insulating particle body. Thereby, it becomes more difficult for the insulating particles to be detached from the surface of the conductive particles by kneading during the production of the anisotropic conductive material. Furthermore, when a plurality of conductive particles with insulating particles come into contact, the insulating particles are difficult to be detached from the surface of the conductive particles. In order to effectively suppress unintentional detachment of the insulating particles, the material of the insulating particles or the insulating particle main body is preferably an inorganic compound, and the insulating particles or the insulating particle main body is Inorganic particles are preferred. In order to effectively suppress unintentional detachment of the insulating particles, the layer covering at least a part of the surface of the insulating particle main body is preferably formed of an organic compound. The compound is preferably a polymer compound.

  The conductive particles with insulating particles have a layer formed of a polymer compound using a polymer compound or a compound that becomes a polymer compound so as to cover at least a part of the surface of the insulating particle body. It is preferably obtained through a step of forming and obtaining insulating particles and a step of obtaining the conductive particles with insulating particles by attaching the insulating particles to the surfaces of the conductive particles having at least the conductive portion on the surface. .

  The conductive particles with insulating particles according to the present invention preferably further include a coating covering the surface of the conductive particles. The coating preferably covers the surface of the conductive particles and the surface of the insulating particles. By the said film, the surface of an electroconductive part is not exposed or the exposed area of the surface of an electroconductive part decreases, and it becomes difficult to produce rust in an electroconductive part. For this reason, high conductivity can be maintained over a long period of time, and conduction reliability between the electrodes can be increased.

  From the viewpoint of making rust more unlikely to occur in the conductive part, the film is preferably formed of a compound having an alkyl group having 6 to 22 carbon atoms.

  The conductive particles with insulating particles according to the present invention are preferably conductive particles with insulating particles used in a paste-like anisotropic conductive paste.

  When electrodes are connected using conductive particles with insulating particles, short-circuiting between adjacent electrodes that should not be connected is more difficult to occur, and there is sufficient continuity between the upper and lower electrodes to be connected. From the viewpoint of ensuring the above, the conductive particles with insulating particles according to the present invention are used for anisotropic conductive pastes having a viscosity of more than 200 Pa · s and not more than 1000 Pa · s at 25 ° C. and 2.5 rpm. The viscosity of the anisotropic conductive paste at 25 ° C. and 2.5 rpm is preferably more than 200 Pa · s and 1000 Pa · s or less.

  From the viewpoint of further enhancing the conduction reliability and insulation reliability between the electrodes, the coefficient of variation of the particle diameter of the conductive particles with insulating particles is preferably 8% or less, more preferably 5% or less.

  The coefficient of variation (CV value) is expressed by the following equation.

CV value (%) = (ρ / Dn) × 100
ρ: Standard deviation of particle diameter of conductive particles with insulating particles Dn: Average value of particle diameter of conductive particles with insulating particles

  The compression elastic modulus of the conductive particles with insulating particles is preferably 1 GPa or more, more preferably 2 GPa or more, preferably 7 GPa or less, more preferably 5 GPa or less.

  The compression recovery rate of the conductive particles with insulating particles is preferably 20% or more, more preferably 30% or more, preferably 60% or less, more preferably 50% or less.

  The compression elastic modulus (10% K value) at 20 ° C. of the conductive particles with insulating particles is measured as follows.

  Using a micro-compression tester, the conductive particles with insulating particles are compressed under the conditions of a compression speed of 0.33 mN / sec and a maximum test load of 20 mN on the end face of a diamond cylinder having a diameter of 50 μm. 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 (N / mm ² ) = (3/2 ^1/2 ) · F · S ⁻³ / ² · R ^−1/2
F: Load value (N) when conductive particles with insulating particles are compressively deformed by 10%
S: Compression displacement (mm) when conductive particles with insulating particles are 10% compressively deformed
R: radius of conductive particles with insulating particles (mm)

  The compression elastic modulus universally and quantitatively represents the hardness of the conductive particles with insulating particles. By using the compression modulus, the hardness of the conductive particles with insulating particles can be expressed quantitatively and uniquely.

  The compression recovery rate can be measured as follows.

  Disperse conductive particles with insulating particles on the sample stage. With respect to one dispersed conductive particle with insulating particles, a load is applied to the reversal load value (5.00 mN) in the center direction of the conductive particles with insulating particles 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: Compressive displacement from the load value for the origin to the reverse load value when applying the load L2: Compressive displacement from the reverse load value to the load value for the origin when releasing the load

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

(Conductive particles with insulating particles)
FIG. 1 is a sectional view showing conductive particles with insulating particles according to the first embodiment of the present invention.

  A conductive particle 1 with insulating particles shown in FIG. 1 includes conductive particles 2 and a plurality of insulating particles 3 attached to the surface of the conductive particles 2. Insulating particles 43 described later may be used instead of the insulating particles 3.

  The insulating particle 3 has an insulating particle body 5 and a layer 6 covering the surface of the insulating particle body 5. The layer 6 is preferably formed of an organic compound, and is preferably formed of a polymer compound. The insulating particles 3 are made of an insulating material. The insulating particles 3 are coated particles.

  The layer 6 covers the entire surface of the insulating particle body 5. Therefore, the layer 6 is disposed between the conductive particles 2 and the insulating particle main body 5. The layer 6 may be present so as to cover at least a part of the surface of the insulating particle main body, and may not cover the entire surface of the insulating particle main body. The layer 6 is preferably disposed between the conductive particles and the insulating particle main body.

  The conductive particle 2 includes a base particle 11 and a conductive portion 12 disposed on the surface of the base particle 11. The conductive part 12 is a conductive layer. The conductive part 12 covers the surface of the base particle 11. The conductive particle 2 is a coated particle in which the surface of the base particle 11 is coated with the conductive portion 12. The conductive particle 2 has a conductive portion 12 on the surface.

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

  The conductive particles 21 with insulating particles shown in FIG. 2 include conductive particles 22 and a plurality of insulating particles 3 attached to the surface of the conductive particles 22. Insulating particles 43 described later may be used instead of the insulating particles 3.

  The conductive particle 22 includes the base particle 11 and a conductive portion 31 disposed on the surface of the base particle 11. The conductive part 31 is a conductive layer. The conductive particles 22 have a plurality of core substances 32 on the surface of the substrate particles 11. The conductive portion 31 covers the base particle 11 and the core substance 32. By covering the core substance 32 with the conductive portion 31, the conductive particles 22 have a plurality of protrusions 33 on the surface. The surface of the conductive portion 31 is raised by the core substance 32, and a plurality of protrusions 33 are formed.

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

  A conductive particle 41 with insulating particles shown in FIG. 3 includes conductive particles 42 and a plurality of insulating particles 43 attached to the surface of the conductive particles 42. The insulating particles 3 may be used instead of the insulating particles 43.

  The conductive particle 42 includes the base particle 11 and a conductive portion 51 disposed on the surface of the base particle 11. The conductive part 51 is a conductive layer. The conductive particles 42 do not have a core substance like the conductive particles 22. The conductive portion 51 has a first portion and a second portion that is thicker than the first portion. The conductive particles 42 have a plurality of protrusions 52 on the surface. A portion excluding the plurality of protrusions 52 is the first portion of the conductive portion 51. The plurality of protrusions 52 are the second portions where the conductive portion 51 is thick. The insulating particles 43 are not coated particles.

  FIG. 4 is a sectional view showing conductive particles with insulating particles according to the fourth embodiment of the present invention.

  The conductive particles 61 with insulating particles shown in FIG. 4 include conductive particles 2, a plurality of insulating particles 43 attached to the surface of the conductive particles 2, and the conductive particles 2 and the insulating particles 43. And a coating 62 covering the surface. The conductive particles 22 and 42 may be used instead of the conductive particles 2. The insulating particles 3 may be used instead of the insulating particles 43.

  The coating 62 does not necessarily have to cover the entire surfaces of the conductive particles 2 and the insulating particles 43. The coating 62 preferably covers the entire surfaces of the conductive particles 2, the conductive portions 12, and the insulating particles 43. It is preferable that the surfaces of the conductive particles 2, the conductive portions 12, and the insulating particles 43 are not exposed by the coating 62. Since the coating 62 covers at least a part of the surface of the conductive portion 12, rust of the conductive portion 12 can be suppressed in the portion where the coating 62 is formed.

  From the viewpoint of making the conductive portion 12 even more difficult to rust, the treatment liquid containing the peeled coating 62 is obtained by treating the conductive particles 61 with insulating particles with a 5 wt% aqueous citric acid solution and peeling the coating 62. It is preferable that the filtrate obtained by filtering the treatment liquid after obtaining the above contains 50 ppm or more and 10,000 ppm or less of the phosphorus element. From the viewpoint of making the conductive portion 12 even more difficult to rust, the treatment liquid containing the peeled coating 62 is obtained by treating the conductive particles 61 with insulating particles with a 5 wt% aqueous citric acid solution and peeling the coating 62. It is preferable that the filtrate obtained by filtering the treatment liquid after obtaining the above contains 50 ppm or more and 10,000 ppm or less of silicon element. The content of silicon element or phosphorus element in the filtrate is more preferably 100 ppm or more, more preferably 5000 ppm or less, and still more preferably 1000 ppm or less.

  The contents of the phosphorus element and silicon element can be measured using an ICP emission analyzer. Examples of commercially available ICP emission analyzers include “ULTIMA2” manufactured by HORIBA, Ltd.

  In the case of the conductive particles 61 with insulating particles having the coating 62, the contents of the phosphorus element and the silicon element are usually determined by the coating 62. That is, the contents of the phosphorus element and the silicon element indicate the ratio of the phosphorus element and the silicon element in the coating 62.

  In the conductive particles with insulating particles 1, 21, 41, 61, the specific gravity ratio of the specific gravity A of the conductive particles with insulating particles 1, 21, 41, 61 to the specific gravity B of the conductive particles 2, 22, 42 (A / B) is less than 0.97. The specific gravity of the conductive particles 2, 22, 42 is 2.0 or more and 3.5 or less. By producing such an anisotropic conductive material by mixing such conductive particles with insulating particles 1, 21, 41, 61 with a binder resin, the conductive particles with insulating particles in the anisotropic conductive material 1, Sedimentation of 21, 41, 61 can be remarkably suppressed. For this reason, the connection resistance between the upper and lower electrodes can be effectively reduced, and the electrodes can be more reliably conducted. Furthermore, it is difficult for a short circuit to occur between adjacent electrodes that should not be connected.

  Hereinafter, details of the conductive particles, the insulating particles, and the coating will be described.

[Conductive particles]
Conductive particles with insulating particles can be obtained by attaching the insulating particles to the surface of the conductive particles having at least a conductive portion on the surface. The conductive part in the conductive particles is preferably a conductive layer.

  The said electroconductive particle should just have an electroconductive part on the surface at least. The conductive particles may be conductive particles having base particles and conductive portions arranged on the surface of the base particles. The conductive particles may be metal particles whose entirety is a conductive part. Among these, from the viewpoint of reducing the cost, increasing the flexibility of the conductive particles, and improving the conduction reliability between the electrodes, the base particles were provided on the surface of the base particles. Conductive particles having a conductive part are preferred.

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

  The substrate particles are preferably resin particles formed of a resin. When connecting the electrodes using the conductive particles with insulating particles, the conductive particles with insulating particles are compressed by placing the conductive particles with insulating particles between the electrodes and then pressing them. When the substrate particles are resin particles, the conductive particles are likely to be deformed during the pressure bonding, and the contact area between the conductive particles and the electrode is increased. For this reason, the conduction | electrical_connection reliability between electrodes becomes high.

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

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

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

  The metal for forming the conductive part is not particularly limited. Furthermore, in the case where the conductive particles are metal particles that are conductive parts as a whole, the metal for forming the metal particles is not particularly limited. Examples of the metal include gold, silver, copper, palladium, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, thallium, germanium, cadmium, silicon, and these. And the like. Examples of the metal include tin-doped indium oxide (ITO) and solder. Especially, since the connection resistance between electrodes becomes still lower, an alloy containing tin, nickel, palladium, copper or gold is preferable, and nickel or palladium is more preferable.

  In many cases, hydroxyl groups are present on the surface of the conductive portion by oxidation. In general, a hydroxyl group exists on the surface of a conductive portion formed of nickel by oxidation. Such a conductive portion having a hydroxyl group is easily chemically bonded to the insulating particles, for example, chemically bonded to the insulating particles having a hydroxyl group.

  The conductive layer may be formed of a single layer. 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 the gold layer or the palladium layer Is more preferable, and a gold layer is particularly 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.

  As a method for forming a conductive layer on the surface of the substrate particles, a method by physical collision is also effective from the viewpoint of improving productivity. As a method of forming by physical collision, for example, there is a method of coating using a theta composer (manufactured by Tokuju Kogakusha Co., Ltd.).

  The average particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 100 μm or less, more preferably 20 μm or less, and even more preferably 5 μm or less. When the average particle diameter of the conductive particles is not less than the above lower limit and not more than the above upper limit, the contact area between the conductive particles and the electrodes is sufficiently large when the electrodes are connected using the conductive particles with insulating particles. And it becomes difficult to form aggregated conductive particles 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 “average particle size” of the conductive particles indicates a number average particle size. The average particle diameter of the conductive particles can be obtained by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value.

  The thickness of the conductive layer is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 1 μm or less, more preferably 0.3 μm or less. 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 the thickness of the gold layer when the outermost layer is a gold layer. It is 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 lower limit and not more than the upper limit, the outermost conductive layer can be uniformly coated, the corrosion resistance is sufficiently high, and the connection resistance between the electrodes is sufficiently high. Lower.

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

  The conductive particles preferably have protrusions on the surface. The conductive particles preferably have a plurality of protrusions on the surface of the conductive part. It is preferable that there are a plurality of the protrusions. An oxide film is often formed on the surface of the electrode connected by the conductive particles with insulating particles. Furthermore, an oxide film is often formed on the surface of the conductive part of the conductive particles. By using conductive particles having protrusions, the oxide film is effectively eliminated by the protrusions by placing the conductive particles with insulating particles between the electrodes and then pressing them. For this reason, an electrode and electroconductive particle contact still more reliably and the connection resistance between electrodes becomes low. Furthermore, the insulating particles between the conductive particles and the electrode can be effectively excluded by the protrusions of the conductive particles. For this reason, the conduction | electrical_connection reliability between electrodes becomes still higher.

  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 by electroless plating on the surface of the base particles Examples of the method include forming a conductive layer, then attaching a core substance, and further forming a conductive layer by electroless plating. Further, when the conductive layer is formed by electroless plating or the like, the protrusion can also be formed by partially varying the thickness of the conductive layer.

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

  The conductive particles may have a first conductive layer on the surface of the base particle, and may have a second conductive layer on the first conductive layer. In this case, a core substance may be attached to the surface of the first conductive layer. The core material is preferably covered with a second conductive layer. The thickness of the first conductive layer is preferably in the range of 0.05 to 0.5 μm. The conductive particles form a first conductive layer on the surface of the base particle, and then a core material is deposited on the surface of the first conductive layer, and then the first conductive layer and the core material are formed. It is preferably obtained by forming a second conductive layer on the surface.

  Examples of the conductive material constituting the core material include conductive non-metals such as metals, metal oxides, and graphite, and conductive polymers. Examples of the conductive polymer include polyacetylene. Among them, metal is preferable because conductivity can be increased.

  Examples of the metal include gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium, and cadmium, and tin-lead. Examples include alloys composed of two or more metals such as alloys, tin-copper alloys, tin-silver alloys, and tin-lead-silver alloys. Of these, nickel, copper, silver or gold is preferable. The metal constituting the core substance may be the same as or different from the metal constituting the conductive part (conductive layer).

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

[Insulating particles]
The insulating particles are particles having insulating properties. Insulating particles are smaller than conductive particles. When the electrodes are connected using conductive particles with insulating particles, the insulating particles can prevent a short circuit between adjacent electrodes. Specifically, when the conductive particles with a plurality of insulating particles are in contact with each other, there are insulating particles between the conductive particles in the conductive particles with a plurality of insulating particles. Short circuit between the electrodes adjacent in the lateral direction can be prevented. In addition, the insulating particle between an electroconductive part and an electrode can be easily excluded by pressurizing the electroconductive particle with an insulating particle with two electrodes in the case of the connection between electrodes. In the case where protrusions are provided on the surface of the conductive particles, the insulating particles between the conductive portion and the electrode can be easily removed. Furthermore, since the protruding portion facilitates contact with the electrode, connection reliability is improved.

  Examples of the material constituting the insulating particles include an insulating resin and an insulating inorganic substance. As said insulating resin, the said resin quoted as resin for forming the resin particle which can be used as a base particle is mentioned. As said insulating inorganic substance, the said inorganic substance quoted as an inorganic substance for forming the inorganic particle which can be used as a base particle is mentioned.

  Specific examples of the insulating resin that is the material of the insulating particles include polyolefins, (meth) acrylate polymers, (meth) acrylate copolymers, block polymers, thermoplastic resins, crosslinked thermoplastic resins, heat Examples thereof include curable resins and water-soluble resins.

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

  From the viewpoint of further improving the detachability of the insulating particles during thermocompression bonding, the insulating particles or the insulating particle main body is preferably inorganic particles, and is preferably silica particles. Examples of the inorganic particles include shirasu particles, hydroxyapatite particles, magnesia particles, zirconium oxide particles, and silica particles. Examples of the silica particles include pulverized silica and spherical silica, and spherical silica is preferably used. The silica particles preferably have a functional group capable of chemical bonding such as a carboxyl group and a hydroxyl group on the surface, and more preferably have a hydroxyl group. Inorganic particles are relatively hard, especially silica particles are relatively hard. When conductive particles with insulating particles using such hard insulating particles as insulating particles are added to a binder resin and kneaded, the insulating particles are hard, so that the insulating particles are removed from the surface of the conductive particles. There is a tendency to detach easily. In the case where the insulating particles have a layer formed of the polymer compound, even if hard insulating particles are used, it is possible to suppress the separation of the hard insulating particles during the kneading.

  The layer formed of the organic compound and the layer formed of the polymer compound serve as a flexible layer, for example. The polymer compound in the layer formed of the polymer compound or the compound that becomes the polymer compound by polymerization or the like is preferably a compound having a polymerizable reactive functional group. The polymerizable reactive functional group is preferably an unsaturated double bond. For example, a compound having an unsaturated double bond (a compound that becomes a polymer compound) may be subjected to a polymerization reaction on the surface of the insulating particle main body, and the reactive functional group on the surface of the polymer compound and the insulating particle main body. And may be reacted. Examples of the polymer compound include a compound having a (meth) acryloyl group, a compound having an epoxy group, and a compound having a vinyl group. From the viewpoint of suppressing detachment of the insulating particles from the surface of the conductive particles when dispersing the conductive particles with insulating particles, the polymer compound or the compound to be the polymer compound is (meth) It preferably has at least one reactive functional group selected from the group consisting of an acryloyl group, a glycidyl group and a vinyl group. Among these, from the viewpoint of further suppressing the detachment of the insulating particles, the polymer compound or the compound to be the polymer compound preferably has a (meth) acryloyl group.

  Specific examples of the compound having the (meth) acryloyl group include methacrylic acid, hydroxyethyl acrylate, and ethylene glycol dimethacrylate.

  Specific examples of the epoxy compound include bisphenol A type epoxy resin and resorcinol glycidyl ether.

  Specific examples of the compound having a vinyl group include styrene and vinyl acetate.

  The polymer compound preferably has a weight average molecular weight of 1000 or more. The upper limit of the weight average molecular weight of the polymer compound is not particularly limited, but the polymer compound preferably has a weight average molecular weight of 20000 or less. The weight average molecular weight indicates a value in terms of polystyrene measured by gel permeation chromatography (GPC).

  A method for forming the layer formed of the polymer compound on the surface of the insulating particle body is not particularly limited. Using a polymer compound or a compound that becomes a polymer compound so as to cover at least a part of the surface of the insulating particle main body, a layer formed of the polymer compound is formed to obtain insulating particles. preferable. As an example of a method for forming a layer formed of the polymer compound, a compound having a reactive double bond and a hydroxyl group is formed on an insulating particle body having a reactive functional group such as a vinyl group on the surface. And a method of polymerizing on the surface. However, methods other than this forming method may be used.

  The insulating particle body and the layer are preferably chemically bonded. This chemical bond includes a covalent bond, a hydrogen bond, an ionic bond, a coordination bond, and the like. Of these, a covalent bond is preferable, and a chemical bond using a reactive functional group is preferable.

  Examples of the reactive functional group that forms the chemical bond include a vinyl group, (meth) acryloyl group, silane group, silanol group, carboxyl group, amino group, ammonium group, nitro group, hydroxyl group, carbonyl group, and thiol group. Sulfonic acid group, sulfonium group, boric acid group, oxazoline group, pyrrolidone group, phosphoric acid group and nitrile group. Among these, a vinyl group and a (meth) acryloyl group are preferable.

  From the viewpoint of further suppressing the detachment of the insulating particles and further improving the insulation reliability in the connection structure, it is possible to use an insulating particle body having a reactive functional group on the surface as the insulating particle body. preferable. From the viewpoint of further suppressing the detachment of the insulating particles and further improving the insulation reliability in the connection structure, the insulating particles subjected to surface treatment using a compound having a reactive functional group as the insulating particle main body. It is preferable to use a particle body. From the viewpoint of further suppressing the detachment of the insulating particles and further improving the insulation reliability in the connection structure, the insulating particle main body having a reactive functional group on the surface, the polymer compound, or the polymer compound And the layer formed of the polymer compound is chemically bonded to the reactive functional group on the surface of the insulating particle body using the compound to form the insulating particle body and the layer. It is preferable that the insulating particles that are chemically bonded are obtained.

  Examples of the reactive functional group on the surface of the insulating particle body include a (meth) acryloyl group, a glycidyl group, a hydroxyl group, a vinyl group, and an amino group. The reactive functional group on the surface of the insulating particle body is at least one reactive functional group selected from the group consisting of a (meth) acryloyl group, a glycidyl group, a hydroxyl group, a vinyl group, and an amino group. Is preferred.

  Examples of the compound (surface treatment substance) for introducing the reactive functional group onto the surface of the insulating particle body include a compound having a (meth) acryloyl group, a compound having an epoxy group, and a compound having a vinyl group. It is done.

  As a compound (surface treatment substance) for introducing a vinyl group as the reactive functional group onto the surface of the insulating particle body, a silane compound having a vinyl group, a titanium compound having a vinyl group, and a vinyl group are used. The phosphoric acid compound etc. which have are mentioned. The surface treatment substance is preferably a silane compound having a vinyl group. Examples of the silane compound having a vinyl group include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, and vinyltriisopropoxysilane.

  As a compound (surface treatment substance) for introducing the (meth) acryloyl group which is the reactive functional group onto the surface of the insulating particle main body, a silane compound having a (meth) acryloyl group and a (meth) acryloyl group And a phosphoric acid compound having a (meth) acryloyl group. The surface treatment substance is also preferably a silane compound having a (meth) acryloyl group. Examples of the silane compound having a (meth) acryloyl group include (meth) acryloxypropyltriethoxysilane, (meth) acryloxypropyltrimethoxysilane, (meth) acryloxypropyltridimethoxysilane, and the like.

  It is preferable that the insulating particles are not formed by friction by mixing using the insulating particle main body and the polymer compound or the compound to be the polymer compound. Moreover, it is preferable that the surface of the insulating particle body is not covered with the layer using a hybridization method. When insulating particles are formed using friction by mixing or a hybridization method, the layer is easily detached from the surface of the insulating particle body. In addition, the fragments of the layer formed during kneading easily adhere to the surface of the insulating particles. For this reason, a layer or a fragment of the layer detached on the surface of the conductive layer of the conductive particles with insulating particles tends to adhere, and the conduction reliability in the connection structure tends to decrease. Therefore, from the viewpoint of further suppressing the detachment of the insulating particles and further increasing the insulation reliability and conduction reliability in the connection structure, it is preferable that the insulating particles are not formed by friction due to mixing. It is preferable not to use a hybridization method.

  When the insulating particles are obtained, the amount of the polymer compound or the compound that becomes the polymer is preferably 30 parts by weight or more, more preferably 50 parts by weight or more, preferably 100 parts by weight of the insulating particle body. Is 500 parts by weight or less, more preferably 300 parts by weight or less. A favorable layer can be formed as the usage-amount of the said high molecular compound is more than the said minimum and below the said upper limit.

  The following manufacturing conditions are mentioned as an example of the specific manufacturing conditions of the layer formed with the said high molecular compound.

  First, in 100 to 500 parts by weight of a solvent such as water, 1 to 3 parts by weight of an insulating particle body having a reactive functional group on the surface, and 0.1 to 20 parts by weight of a compound having a reactive double bond and a hydroxyl group (Preferably 0.1 to 1 part by weight), cross-linking agent 0.01 to 5 parts by weight (preferably 0.01 to 1 part by weight), dispersant 0.1 to 5 parts by weight (preferably 0.1 to 3 parts) Parts by weight) and 0.1-5 parts by weight (preferably 0.1-3 parts by weight) of a thermal polymerization initiator. Next, while stirring with a three-one motor, the temperature is raised to a temperature higher than the reaction temperature of the thermal polymerization initiator in an oil bath, polymerization is started, and the state is maintained for 5 hours or longer to react. Thereafter, unreacted compounds are removed using a centrifuge to obtain insulating particles in which the surface of the insulating particle main body is covered with the layer.

  When there are hydroxyl groups on the surface of the insulating particles and the surface of the conductive particles, the adhesion between the insulating particles and the conductive particles is moderately increased by the dehydration reaction.

  Examples of the compound having a hydroxyl group for introducing a hydroxyl group include a P—OH group-containing compound and a Si—OH group-containing compound.

  Specific examples of the P-OH group-containing compound include acid phosphooxyethyl methacrylate, acid phosphooxypropyl methacrylate, acid phosphooxypolyoxyethylene glycol monomethacrylate, and acid phosphooxypolyoxypropylene glycol monomethacrylate. As for the said P-OH group containing compound, only 1 type may be used and 2 or more types may be used together.

  Specific examples of the Si-OH group-containing compound include vinyltrihydroxysilane and 3-methacryloxypropyltrihydroxysilane. As for the said Si-OH group containing compound, only 1 type may be used and 2 or more types may be used together.

  For example, insulating particles having a hydroxyl group on the surface can be obtained by a treatment using a silane coupling agent. Examples of the silane coupling agent include hydroxytrimethoxysilane.

  The particle diameter of the insulating particles can be appropriately selected depending on the particle diameter of the conductive particles, the use of the conductive particles with insulating particles, and the like. The average particle diameter of the insulating particles is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 5 μm or less, more preferably 2.5 μm or less, still more preferably 1 μm or less, and particularly preferably 0.5 μm or less. It is. When the average particle diameter of the insulating particles is not less than the above lower limit, the conductive particles in the plurality of conductive particles with insulating particles are difficult to contact when the conductive particles with insulating particles are dispersed in the binder resin. Become. When the average particle diameter of the insulating particles is not more than the above upper limit, it is not necessary to make the pressure too high in order to eliminate the insulating particles between the electrodes and the conductive particles when connecting the electrodes, There is no need to heat to high temperatures.

  The “average particle diameter” of the insulating particles indicates a number average particle diameter. The average particle size of the insulating particles is determined using a particle size distribution measuring device or the like.

  The average particle diameter of the insulating particles is preferably 1/2 or less of the particle diameter of the conductive particles, more preferably 1/3 or less, still more preferably 1/4 or less. / 5 or less is particularly preferable. The particle diameter of the insulating particles is preferably 1/1000 or more of the particle diameter of the conductive particles, more preferably 1/10 or more, and even more preferably more than 1/10. When the average particle diameter of the insulating particles is 1/5 or less of the particle diameter of the conductive particles, for example, when producing conductive particles with insulating particles, the insulating particles are more efficient on the surface of the conductive particles. Adheres.

  The average particle diameter of the insulating particles is preferably more than 1/10 and less than 1/3 of the particle diameter of the conductive particles. In this case, it can suppress even more effectively that several electroconductive particle in several electroconductive particle with an insulating particle contacts. In particular, when electrically connecting electrodes using an anisotropic conductive material containing conductive particles with insulating particles and a binder resin, it is even more effective to prevent contact between multiple conductive particles. it can. Moreover, when electrically connecting electrodes using a paste-like anisotropic conductive material, it can suppress more effectively that several electroconductive particle contacts. For this reason, it is more difficult to connect the electrodes adjacent to each other in the lateral direction that should not be connected, and the occurrence of a short circuit between the adjacent electrodes can be further suppressed. On the other hand, the insulating particles in the conductive particles with insulating particles can be more effectively excluded from the gap between the electrode and the conductive particles at the time of pressure bonding. For this reason, the conduction | electrical_connection reliability between the upper and lower electrodes which should be connected can be improved considerably.

  In addition, the smaller the particle diameter of the conductive particles, the better the insulation reliability is improved because the average particle diameter of the insulating particles exceeds 1/10 of the particle diameter of the conductive particles and is 1/3 or less. It gets quite big. In particular, when the particle diameter of the conductive particles is 1 μm or more and 5 μm or less, the average particle diameter of the insulating particles exceeds 1/10 of the particle diameter of the conductive particles, and is 1/3 or less. The insulation reliability between the electrodes is further effectively increased. This is because, when the particle size of the conductive particles is small, the curvature becomes large. Therefore, when the distance between the insulating particles is the same, the conductive layer portion jumps out, and in order to ensure insulation, the particles of the insulating particles This is because it is necessary to increase the diameter.

  From the viewpoint of further enhancing the conduction reliability and the insulation reliability between the electrodes, the average particle diameter of the insulating particles is preferably more than 1/8 of the particle diameter of the conductive particles, and is 1 / 7.5 or more. Is more preferably 1 / 3.5 or less, and still more preferably 1/4 or less. The average particle diameter of the insulating particles may exceed 1/5 of the particle diameter of the conductive particles, or may be 1 / 4.5 or more.

  The average particle diameter of the insulating particles is preferably 0.5 times or more the thickness of the conductive layer in the conductive particles, and more preferably 1 time or more. The average particle size of the insulating particles is preferably 20 times or less, more preferably 10 times or less the thickness of the conductive layer in the conductive particles. When the average particle diameter of the insulating particles and the thickness of the conductive layer satisfy such a preferable relationship, the conductive particles in the plurality of conductive particles with insulating particles are difficult to contact with each other, and the conductive layer and the electrode are not in contact with each other. Insulating particles can be easily eliminated.

  The average particle diameter of the insulating particles is preferably 0.5 times or more, more preferably 1 time or more, the average particle diameter of the core substance. The average particle size of the insulating particles is preferably 20 times or less, more preferably 10 times or less, the average particle size of the core substance. When the average particle diameter of the insulating particles and the average particle diameter of the core substance satisfy such a preferable relationship, the conductive particles in the plurality of conductive particles with insulating particles are difficult to contact each other, and the conductive layer and Insulating particles between the electrodes can be easily eliminated.

  The “average particle size” of the core substance indicates a number average particle size. The average particle size of the core substance is determined using a particle size distribution measuring device or the like.

  The elastic modulus of the insulating particle body is preferably 1/1 or less, more preferably 1/2 or less, of the elastic modulus of the conductive layer in the conductive particles. The elastic modulus of the insulating particle body is preferably 1/100 or more, and more preferably 1/50 or more, of the elastic modulus of the conductive layer in the conductive particles. When the elastic modulus of the insulating particles and the elastic modulus of the conductive layer satisfy such a preferable relationship, the conductive particles in the plurality of conductive particles with insulating particles are difficult to contact each other, and the conductive layer and the electrode Insulating particles can be easily eliminated.

  The elastic modulus is measured according to JIS K7208 using a precision universal testing machine.

  When the average particle diameter of the insulating particles is 200 nm, the sphericity of the insulating particles is preferably 50 nm or less.

  The coefficient of variation (CV value) of the insulating particles is preferably 1% or more, preferably 10% or less, more preferably 8% or less.

  Two or more insulating particles having different particle diameters may be used. In this case, since small insulating particles can exist between the large insulating particles on the surface of the conductive particles, the exposed area of the conductive particles can be reduced. Therefore, even if a plurality of conductive particles with insulating particles are in contact with each other, adjacent conductive particles are difficult to contact, and thus a short circuit between adjacent electrodes can be suppressed. The average particle size of the small insulating particles is preferably 1/2 or less of the average particle size of the large insulating particles. The number of small insulating particles is preferably ¼ or less of the number of large insulating particles.

  The layer formed of the polymer compound preferably has higher flexibility than the insulating particle body. In general, a layer formed of a polymer compound formed of an organic compound has higher flexibility than inorganic particles. The flexibility between the layer and the insulating particle body can be evaluated, for example, by measuring the compression recovery rate. Further, by measuring the compression recovery rate of the insulating particles rather than the compression recovery rate of the insulating particle main body and the compression recovery rate of the layer, and calculating the difference from the value of the compression recovery rate of the insulating particles, the layer and The flexibility with the insulating particle body can be determined.

  The compression recovery rate can be calculated, for example, by calculating the ratio of the amount of change in particle size when the weight is released to the amount of change in particle size when a constant load is applied to the insulating particles.

  For example, after insulating particles coated with a layer formed of a polymer compound on the surface of silica particles are compressed with a force of 1 N at 20 ° C. using a micro compression tester (manufactured by Shimadzu Corporation), The compression recovery rate can be measured by measuring the deformation of the particles when the weight is released.

In the measurement, the insulating particles were put into a 1 cm ³ (inner diameter 1 cm × width 1 cm × height 1 cm) stainless steel cup so as to be closely packed, and then 0.90 cm ² (length 0.95 cm × width 0. A 95 cm) stainless steel lid may be installed so as to be movable, a compression test may be performed from the top of the lid, and the compression recovery rate may be measured from the movement range of the lid.

[Coating]
The coating is preferably formed of a compound having an alkyl group having 6 to 22 carbon atoms (hereinafter also referred to as compound A). When the carbon number of the alkyl group is 6 or more, rust is more unlikely to occur on the surface of the conductive portion. When the carbon number of the alkyl group is 22 or less, the conductivity of the conductive particles with insulating particles is increased. From the viewpoint of further increasing the conductivity of the conductive particles with insulating particles, the alkyl group in the compound A preferably has 16 or less carbon atoms. The alkyl group may have a linear structure or a branched structure. The alkyl group preferably has a linear structure.

  The compound A is not particularly limited as long as it has an alkyl group having 6 to 22 carbon atoms. The compound A has a phosphate ester having an alkyl group having 6 to 22 carbon atoms or a salt thereof, a phosphite ester having an alkyl group having 6 to 22 carbon atoms or a salt thereof, and an alkyl group having 6 to 22 carbon atoms. It is preferably at least one selected from the group consisting of alkoxysilanes, alkylthiols having an alkyl group having 6 to 22 carbon atoms, and dialkyl disulfides having an alkyl group having 6 to 22 carbon atoms. That is, the compound A having an alkyl group having 6 to 22 carbon atoms is at least one selected from the group consisting of phosphate esters or salts thereof, phosphite esters or salts thereof, alkoxysilanes, alkylthiols, and dialkyl disulfides. It is preferable that By using these preferable compounds A, it is possible to further prevent rust from being generated in the conductive portion. From the viewpoint of making rust less likely to occur, the compound A is preferably at least one selected from the group consisting of the phosphate ester or a salt thereof, a phosphite ester or a salt thereof and an alkoxysilane, More preferably, the phosphoric acid ester or a salt thereof and a phosphorous acid ester or a salt thereof are at least one of them. As for the said compound A, only 1 type may be used and 2 or more types may be used together.

  The compound A preferably has a reactive functional group capable of reacting with the conductive particles, and preferably has a reactive functional group capable of reacting with the conductive part. The compound A preferably has a reactive functional group capable of reacting with insulating particles. It is preferable that the coating is chemically bonded to the conductive particle portion with insulating particles (conductive particles or insulating particles) excluding the coating. The coating is preferably chemically bonded to the conductive particles, and is preferably chemically bonded to the conductive portion. The coating is preferably chemically bonded to the insulating particles. The coating is more preferably chemically bonded to the conductive particles and the insulating particles, and more preferably chemically bonded to the conductive portions and the insulating particles. Due to the presence of the reactive functional group and the chemical bond, peeling of the film is less likely to occur, and as a result, rust is less likely to occur in the conductive part, and insulating particles are not intended from the surface of the conductive particles. Makes it more difficult to detach.

  Examples of the phosphoric acid ester having an alkyl group having 6 to 22 carbon atoms or a salt thereof include, for example, phosphoric acid hexyl ester, phosphoric acid heptyl ester, phosphoric acid monooctyl ester, phosphoric acid monononyl ester, phosphoric acid monodecyl ester, Monoundecyl phosphate, monododecyl phosphate, monotridecyl phosphate, monotetradecyl phosphate, monopentadecyl phosphate, monohexyl phosphate monosodium salt, monoheptyl phosphate monosodium Salts, monooctyl phosphate monosodium salt, monononyl phosphate monosodium salt, monodecyl phosphate monosodium salt, monoundecyl phosphate monosodium salt, monododecyl phosphate monosodium salt, Phosphate mono tridecyl ester monosodium salt, phosphate acid mono tetradecyl ester monosodium salt and phosphoric acid mono pentadecyl ester monosodium salt. You may use the potassium salt of the said phosphate ester.

  Examples of the phosphite ester having an alkyl group having 6 to 22 carbon atoms or a salt thereof include, for example, hexyl phosphite ester, heptyl phosphite ester, monooctyl phosphite ester, monononyl phosphite ester, Phosphoric acid monodecyl ester, phosphorous acid monoundecyl ester, phosphorous acid monododecyl ester, phosphorous acid monotridecyl ester, phosphorous acid monotetradecyl ester, phosphorous acid monopentadecyl ester, phosphorous acid monohexyl Ester monosodium salt, phosphorous acid monoheptyl ester monosodium salt, phosphorous acid monooctyl ester monosodium salt, phosphorous acid monononyl ester monosodium salt, phosphorous acid monodecyl ester monosodium salt, phosphorous acid monoun Decyl ester monosodium salt, phosphorous acid Dodecyl ester monosodium salt, phosphorous acid mono-tridecyl ester monosodium salt, phosphorous acid mono-tetradecyl ester monosodium salt and phosphorous acid mono-pentadecyl ester monosodium salt. You may use the potassium salt of the said phosphite.

  Examples of the alkoxysilane having an alkyl group having 6 to 22 carbon atoms include hexyltrimethoxysilane, hexyltriethoxysilane, heptyltrimethoxysilane, heptyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, and nonyltri. Methoxysilane, nonyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, undecyltrimethoxysilane, undecyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, tridecyltrimethoxysilane, tridecyltriethoxy Examples include silane, tetradecyltrimethoxysilane, tetradecyltriethoxysilane, pentadecyltrimethoxysilane, and pentadecyltriethoxysilane.

  Examples of the alkyl thiol having an alkyl group having 6 to 22 carbon atoms include hexyl thiol, heptyl thiol, octyl thiol, nonyl thiol, decyl thiol, undecyl thiol, dodecyl thiol, tridecyl thiol, tetradecyl thiol, pentadecyl. Examples include thiol and hexadecyl thiol. The alkyl thiol preferably has a thiol group at the end of the alkyl chain.

  Examples of the dialkyl disulfide having an alkyl group having 6 to 22 carbon atoms include dihexyl disulfide, diheptyl disulfide, dioctyl disulfide, dinonyl disulfide, didecyl disulfide, diundecyl disulfide, didodecyl disulfide, ditridecyl disulfide, ditetradecyl disulfide. Examples include decyl disulfide, dipentadecyl disulfide, and dihexadecyl disulfide.

(Other details of conductive particles with insulating particles)
Examples of a method for attaching insulating particles to the surface of the conductive particles and the surface of the conductive part include a chemical method and a physical or mechanical method. Examples of the chemical method include an interfacial polymerization method, a suspension polymerization method in the presence of particles, and an emulsion polymerization method. Examples of the physical or mechanical method include spray drying, hybridization, electrostatic adhesion, spraying, dipping, and vacuum deposition. However, the hybridization method tends to cause desorption of insulating particles. For this reason, it is preferable that the method for attaching the insulating particles to the surfaces of the conductive particles and the conductive part is a method other than the hybridization method. Among these, a method of attaching insulating particles to the surface of the conductive part via a chemical bond is preferable because the insulating particles are difficult to be detached.

  In the conductive particles with insulating particles according to the present invention, the insulating particles are preferably not attached by a hybridization method. It is preferable that the polymer compound is not attached to a portion other than the portion to which the insulating particles are attached on the surface of the conductive particles. Such conductive particles with insulating particles can be obtained without using a hybridization method.

  As shown in FIG. 7, in the conventional conductive particles 101 with insulating particles using the hybridization method, the surface of the conductive particles 102 has a portion 102b other than the portion 102a to which the insulating particles 103 are attached. Also, the polymer compound 104 adheres. This is because in the hybridization method, a compressive shear force is applied, the insulating particles are repeatedly attached and detached, and the insulating particles are gradually attached. The layer formed of the polymer compound of the insulating particles is peeled off by the compressive shearing force, and the peeled polymer compound is attached to a portion other than the portion where the insulating particles are attached on the surface of the conductive particles. The polymer compound adhering to the portion other than the portion to which the insulating particles adhere on the surface of the conductive particles increases the volume resistivity of the conductive particles or decreases the connection resistance between the electrodes.

  The following method is mentioned as an example of the method of attaching insulating particles to the surface of the said electroconductive particle and the surface of the said electroconductive part.

  First, the conductive particles are put in a solvent such as water, and the insulating particles are gradually added while stirring. After sufficiently stirring, the conductive particles with insulating particles are separated and dried by a vacuum dryer or the like to obtain conductive particles with insulating particles.

  The conductive part preferably has a reactive functional group capable of reacting with insulating particles on the surface, and preferably has a reactive functional group capable of reacting with the coating. The coating preferably has a reactive functional group capable of reacting with the conductive portion on the surface, and preferably has a functional group capable of reacting with the insulating particles. The insulating particles preferably have a reactive functional group capable of reacting with the conductive part on the surface. These reactive functional groups make it difficult for the insulating particles to be unintentionally detached from the surface of the conductive particles. Furthermore, the surface of the conductive part can be sufficiently covered with the coating, and the surface of the insulating particles can be sufficiently covered with the coating.

  As the reactive functional group, an appropriate group is selected in consideration of reactivity. Examples of the reactive functional group include a hydroxyl group, a vinyl group, and an amino group. Since the reactivity is excellent, the reactive functional group is preferably a hydroxyl group. The conductive particles preferably have a hydroxyl group on the surface. The insulating particles preferably have a hydroxyl group on the surface.

  When there are hydroxyl groups on the surface of the insulating particles and the surface of the conductive particles, the adhesion force between the insulating particles and the conductive particles is appropriately increased by the dehydration reaction.

  Examples of the compound having a hydroxyl group include a P—OH group-containing compound and a Si—OH group-containing compound. Examples of the compound having a hydroxyl group for introducing a hydroxyl group on the surface of the insulating particles include a P—OH group-containing compound and a Si—OH group-containing compound.

  Specific examples of the P-OH group-containing compound include acid phosphooxyethyl methacrylate, acid phosphooxypropyl methacrylate, acid phosphooxypolyoxyethylene glycol monomethacrylate, and acid phosphooxypolyoxypropylene glycol monomethacrylate. As for the said P-OH group containing compound, only 1 type may be used and 2 or more types may be used together.

  Specific examples of the Si-OH group-containing compound include vinyltrihydroxysilane and 3-methacryloxypropyltrihydroxysilane. As for the said Si-OH group containing compound, only 1 type may be used and 2 or more types may be used together.

  For example, insulating particles having a hydroxyl group on the surface can be obtained by a treatment using a silane coupling agent. Examples of the silane coupling agent include hydroxytrimethoxysilane.

(Method for producing conductive particles with insulating particles provided with a coating)
A particle having insulating particles attached to the surface of conductive particles having at least a conductive portion on the surface is referred to as a conductive particle body with insulating particles. Regarding the method for producing the conductive particles with insulating particles, the surface of the conductive particle body with insulating particles is coated with the insulating particles using a compound having 6 to 22 carbon atoms (compound A). It is preferable to form a coating so as to cover the surface of the conductive particle body.

  The method for forming a film on the surface of the conductive particle body with insulating particles using the compound A is not particularly limited, and a solution containing the compound A is attached to the surface of the conductive particle body with insulating particles. And the like.

  The solvent in the solution containing the compound A is preferably water. The solvent in the solution containing the compound A may contain tetrahydrofuran and organic solvents such as alcohols such as methanol, ethanol and propanol. After making the said solution adhere to the surface of the electroconductive particle main body with an insulating particle, a solvent is removed as needed.

  The content of the compound A in the solution containing the compound A is appropriately adjusted so that a desired film is obtained. In 100% by weight of the solution containing the compound A, the content of the compound A is preferably in the range of 0.5 to 3% by weight.

  For example, when a reactive functional group capable of reacting with the compound A is present on the surface of the conductive part or the surface of the insulating particles, the reactive functional group and the compound A are reacted to form the conductive part. The compound A can be chemically bonded to the surface of the metal and the surface of the insulating particles.

  Compound having conductive particle body with insulating particles having hydroxyl group in at least a part of the surface, and hydroxyl group on the surface of conductive particle body with insulating particle having a C 6-22 alkyl group having a hydroxyl group It is preferable to form a film so as to coat the surface of the conductive particle body with insulating particles by reacting (hereinafter also referred to as compound A1). Further, the conductive particles have a hydroxyl group on the surface, and the film is formed so as to cover the surface of the conductive particle body with insulating particles by reacting the compound A1 with the hydroxyl group on the surface of the conductive particle. It is preferable. It is preferable that the insulating particles have a hydroxyl group on the surface, and the coating is formed so as to cover the surface of the conductive particle body with insulating particles by reacting the compound A1 with the hydroxyl group on the surface of the insulating particles. . Furthermore, the surface of the conductive particles and the surface of the insulating particles each have a hydroxyl group, and the compound A1 is reacted with the hydroxyl groups on the surface of the conductive particles and the surface of the insulating particles, thereby conducting the conductive particles with insulating particles. It is preferable to form a coating so as to cover the surface of the main body. By forming a film in these preferred embodiments, the surface of the conductive portion can be sufficiently covered with the film, and the surface of the insulating particles can be sufficiently covered with the film. Accordingly, rust is more unlikely to occur in the conductive portion, the coating is difficult to peel off, and the insulating particles are not easily detached unintentionally.

(Anisotropic conductive material)
The anisotropic conductive material according to the present invention includes the above-described conductive particles with insulating particles and a binder resin. When the conductive particles with insulating particles are used, the insulating particles are unlikely to be detached from the surface of the conductive particles when the conductive particles with insulating particles are dispersed in the binder resin.

  The binder resin is not particularly limited. In general, an insulating resin is used as the binder resin. 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 with insulating particles and the binder resin, the anisotropic conductive material includes, for example, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, and an antioxidant. In addition, various additives such as a heat stabilizer, a light stabilizer, an ultraviolet absorber, a lubricant, an antistatic agent and a flame retardant may be contained.

  The method for dispersing the conductive particles with insulating particles in the binder resin is not particularly limited, and a conventionally known dispersion method can be used. As a method for dispersing the conductive particles with insulating particles in the binder resin, for example, the conductive particles with insulating particles are added to the binder resin and then kneaded and dispersed with a planetary mixer or the like. A method, a method in which the conductive particles with insulating particles are uniformly dispersed in water or an organic solvent using a homogenizer or the like, then added to the binder resin, and kneaded and dispersed with a planetary mixer or the like; and Examples include a method of diluting the binder resin with water or an organic solvent, adding the conductive particles with insulating particles, and kneading and dispersing with a planetary mixer or the like.

  The anisotropic conductive material according to the present invention can be used as an anisotropic conductive paste and an anisotropic conductive film. The anisotropic conductive paste may be an anisotropic conductive ink or an anisotropic conductive adhesive. The anisotropic conductive film includes an anisotropic conductive sheet. When the anisotropic conductive material containing the conductive particles of the present invention is used as a film-like adhesive such as an anisotropic conductive film, the film-like adhesive containing the conductive particles with insulating particles is used. A film-like adhesive that does not contain conductive particles with insulating particles may be laminated. However, as described above, the anisotropic conductive material according to the present invention is preferably in the form of a paste, and is preferably an anisotropic conductive paste. The paste form includes liquid.

  In 100% by weight of the anisotropic 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 It is 99.99 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 connection reliability of the connection target member in which the conductive particles with insulating particles are efficiently arranged between the electrodes and connected by the anisotropic conductive material The nature becomes even higher.

  In 100% by weight of the anisotropic conductive material, the content of the conductive particles with insulating 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 Is 20% by weight or less, more preferably 10% by weight or less. When the content of the conductive particles with insulating 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)
By connecting the connection target members using the conductive particles with insulating particles according to the present invention, or using the anisotropic conductive material including the conductive particles with insulating particles according to the present invention and a binder resin. A connection structure can be obtained.

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

  FIG. 5 is a front cross-sectional view schematically showing a connection structure using conductive particles with insulating particles according to the first embodiment of the present invention.

  A connection structure 81 shown in FIG. 5 includes a first connection target member 82, a second connection target member 83, and a connection portion 84 connecting the first and second connection target members 82 and 83. Prepare. The connecting portion 84 is formed of an anisotropic conductive material including the conductive particles 1 with insulating particles. Specifically, it is formed by curing an anisotropic conductive material including a plurality of conductive particles 1 with insulating particles. In FIG. 5, the conductive particles 1 with insulating particles are schematically shown for convenience of illustration. Instead of the conductive particles 1 with insulating particles, the conductive particles with insulating particles 21, 41, 61 may be used.

  The first connection target member 82 has a plurality of electrodes 82b on the upper surface 82a (front surface). The second connection target member 83 has a plurality of electrodes 83b on the lower surface 83a (front surface). The electrode 82b and the electrode 83b are electrically connected by one or a plurality of conductive particles 1 with insulating particles. Therefore, the first and second connection target members 82 and 83 are electrically connected by the conductive particles 1 with insulating particles.

The manufacturing method of the connection structure is not particularly limited. As an example of the manufacturing method of the connection structure, the anisotropic conductive material is disposed between the first connection target member and the second connection target member to obtain a laminate, and then the laminate is heated. And a method of applying pressure. 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.

  When the laminate is heated and pressed, the insulating particles 3 existing between the conductive particles 1 and the electrodes 82b and 83b can be eliminated. For example, during the heating and pressurization, the insulating particles 3 existing between the conductive particles 1 and the electrodes 82b and 83b are melted or deformed, so that the surface of the conductive particles 1 Is partially exposed. In addition, since a large force is applied during the heating and pressurization, a part of the insulating particles 3 is peeled off from the surface of the conductive particles 1 and the surface of the conductive particles 1 is partially exposed. Sometimes. The portion where the surface of the conductive particle 1 is exposed comes into contact with the electrodes 82b and 83b, whereby the electrodes 82b and 83b can be electrically connected via the conductive particle 1.

  Specific examples of the connection target member include electronic components such as a semiconductor chip, a capacitor, and a diode, and circuit components such as a printed board, a flexible printed board, and a glass board. The anisotropic conductive material is preferably an anisotropic conductive material for connecting electronic components. The anisotropic conductive material is a paste-like anisotropic conductive paste, and is preferably applied on the connection target member in a paste-like state.

  The conductive particles with insulating particles according to the present invention are particularly suitable for COG having a glass substrate and a semiconductor chip as connection target members, or FOG having a glass substrate and a flexible printed circuit board (FPC) as connection target members. Is done. The conductive particles with insulating particles according to the present invention may be used for COG or FOG. In the connection structure according to the present invention, the first and second connection target members are preferably a glass substrate and a semiconductor chip, or a glass substrate and a flexible printed board. The first and second connection target members may be a glass substrate and a semiconductor chip, or may be a glass substrate and a flexible printed board.

It is preferable that bumps are provided on a semiconductor chip used in a COG having a glass substrate and a semiconductor chip as connection target members. The bump size is preferably an electrode area of 1000 μm ² or more and 10,000 μm ² or less. The electrode space in the semiconductor chip provided with the bump (electrode) is preferably 30 μm or less, more preferably 20 μm or less, and still more preferably 10 μm or less. For such COG applications, the conductive particles with insulating particles according to the present invention are preferably used. In the FPC used in the FOG using a glass substrate and a flexible printed circuit as a connection target member, the electrode space is preferably 30 μm or less, more preferably 20 μm or less.

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

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

Example 1
Conductive particles (average particle diameter: 3.01 μm, conductive layer thickness: 0.12 μm) having a nickel plating layer (conductive layer) formed on the surface of divinylbenzene resin particles were prepared.

  Moreover, the surface of the silica particle (average particle diameter 200nm) produced using the sol-gel method was coat | covered with vinyltriethoxysilane, and the insulating particle which has a vinyl group on the surface was obtained as an insulating particle main body.

  In 200 mL of water, 1 part by weight of the insulating particle main body, 0.22 parts by weight of methacrylic acid as a polymer compound, and 0.05 part by weight of ethylene glycol dimethacrylate as a compound as a polymer compound And 0.5 parts by weight of an initiator (“V-50” manufactured by Wako Pure Chemical Industries, Ltd.) were heated to 70 ° C. with sufficient stirring with a three-one motor, held at 70 ° C. for 6 hours, and the above monomer Was polymerized.

  Then, it cooled, solid-liquid separation was performed twice with the centrifuge, the excess monomer was removed by washing | cleaning, and the insulating particle by which the whole surface was coat | covered with the high molecular compound was obtained. Next, the obtained insulating particles were dispersed in 30 mL of pure water to obtain a dispersion of insulating particles.

  A 1 L separable flask was charged with 250 mL of pure water, 50 mL of ethanol, and 15 parts by weight of the conductive particles, and stirred sufficiently to obtain a liquid containing conductive particles. To the liquid containing the conductive particles, the dispersion liquid of the insulating particles was dropped over 10 minutes while applying ultrasonic waves, and then heated to 40 ° C. and stirred for 1 hour. Then, it filtered and it was made to dry at 100 degreeC with a vacuum dryer for 8 hours, and the electroconductive particle with an insulating particle was obtained.

(Example 2)
When obtaining insulating particles whose entire surface is coated with a polymer compound, the compound that becomes the polymer compound was changed to 0.33 parts by weight of methacrylic acid and 0.05 parts by weight of divinylbenzene. In the same manner as in Example 1, conductive particles with insulating particles were obtained.

(Example 3)
The surface of the silica particles was coated with methacryloxypropyltriethoxysilane to obtain insulating particles having methacryloyl groups on the surface as the insulating particle main body, and the entire surface was made of a polymer compound using the insulating particle main body. Example 1 except that when the coated insulating particles were obtained, the polymer compound was changed to 0.28 parts by weight of vinyl acetate and 0.05 parts by weight of N, N-methylenebisacrylamide. In the same manner, conductive particles with insulating particles were obtained.

Example 4
Conductivity in which nickel powder (100 nm) is attached as a core material to the surface of divinylbenzene resin particles, and a nickel plating layer (conductive layer) is formed on the surface of divinylbenzene particles to which nickel powder is attached Conductive particles with insulating particles were obtained in the same manner as in Example 1 except that particles (average particle size: 3.03 μm, conductive layer thickness: 0.12 μm) were used.

(Example 5)
Using the physical / mechanical hybridization method, the insulating particles produced in Example 1 were attached to the conductive particles prepared in Example 1 to obtain conductive particles with insulating particles.

(Comparative Example 1)
Conductive particles with insulating particles were obtained in the same manner as in Example 1 except that the surface of the insulating particle main body was not coated with the polymer compound.

  That is, when the insulating particles are attached to the surface of the conductive particles, the insulating particles (not coated with the polymer compound) having the vinyl group on the surface are used as pure water as a dispersion of the insulating particles. A dispersion liquid dispersed in 30 mL was used.

(Comparative Example 2)
Conductive particles with insulating particles were obtained in the same manner as in Example 1 except that the thickness of the conductive layer of the conductive particles was 0.25 μm.

(Comparative Example 3)
Conductive particles with insulating particles were obtained in the same manner as in Example 1 except that the thickness of the conductive layer of the conductive particles was 0.06 μm.

(Evaluation of Examples 1-5 and Comparative Examples 1-3)
(1) Specific gravity measurement Specific gravity A of the conductive particles with insulating particles, specific gravity B of the conductive particles, and specific gravity C of the insulating particles were measured. The specific gravity A and specific gravity B were measured with a specific gravity measuring machine (Acupic: manufactured by Shimadzu Corporation). For specific gravity C, the core particle diameter and the film thickness of the polymer layer were measured by TEM, and the calculated specific gravity calculated therefrom was adopted.

(2) Coverage ratio of conductive particles with insulating particles and residual rate of insulating particles Before sonication, 100 conductive particles with insulating particles of Examples and Comparative Examples were observed by observation with an SEM. . The coverage X1 which is the area of the part coat | covered with the insulating particle which occupies for the whole surface area of the electroconductive particle in the electroconductive particle with an insulating particle was calculated | required.

  Next, 3 parts by weight of conductive particles with insulating particles was added to 100 parts by weight of ethanol to obtain a conductive particle-containing liquid with insulating particles. The conductive particle-containing liquid with insulating particles was subjected to ultrasonic treatment while being stirred for 5 minutes at 20 ° C. and 40 kHz with an ultrasonic cleaner. After the ultrasonic treatment, 100 conductive particles with insulating particles are observed by observation with an SEM, and the portion of the conductive particles with insulating particles covered by the insulating particles occupying the entire surface area of the conductive particles. The area coverage X2 was determined. The remaining rate of the insulating particles was obtained from the following formula (1) from the coverage X1 and the coverage X2.

  Residual rate of insulating particles (%) = (coverage ratio X2 after ultrasonic treatment / coverage ratio X1 before ultrasonic treatment) × 100 Formula (1)

(3) Preparation of connection structure The conductive particles with insulating particles of Examples and Comparative Examples were added to and dispersed in “Struct Bond XN-5A” manufactured by Mitsui Chemicals so that the content would be 10% by weight. An anisotropic conductive paste was obtained.

  A transparent glass substrate having an ITO electrode pattern with an L / S of 30 μm / 30 μm formed on the upper surface was prepared. Further, a semiconductor chip was prepared in which a copper electrode pattern having L / S of 30 μm / 30 μm was formed on the lower surface.

  On the transparent glass substrate, the obtained anisotropic conductive paste was applied to a thickness of 30 μm to form an anisotropic conductive paste layer. Next, the semiconductor chip was stacked on the anisotropic conductive paste layer so that the electrodes face each other. Then, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer becomes 185 ° C., a pressure heating head is placed on the upper surface of the semiconductor chip and a pressure of 1 MPa is applied to form the anisotropic conductive paste layer. Completely cured at 185 ° C. to obtain a connection structure.

(4) Conductivity evaluation (between upper and lower electrodes)
The connection resistance between the upper and lower electrodes of the obtained connection structure was measured by a four-terminal method. The average value of the two connection resistances was calculated. Note that the connection resistance can be obtained by measuring the voltage when a constant current is passed from the relationship of voltage = current × resistance. “○” when the average value of the connection resistance is 2.0Ω or less, and the average value of the connection resistance is 2.0Ω or less, but the portion other than the portion where the insulating particles adhere to the surface of the conductive particles In addition, the case where there was a portion where the polymer compound was attached was determined as “Δ”, and the case where the average value of the connection resistance exceeded 2.0Ω was determined as “×”.

(5) Insulation evaluation (between adjacent electrodes in the horizontal direction)
In the obtained connection structure, the presence or absence of leakage between adjacent electrodes was evaluated by measuring resistance with a tester. When the resistance exceeded 500 MΩ, it was judged that there was no leak and the result was judged as “◯”, and when the resistance was 500 MΩ or less, it was judged that there was a leak and the result was judged as “X”.

  The results are shown in Table 1 below.

  In addition, in the insulating particles obtained in Examples 1 to 4, it was confirmed that the layer formed of the polymer compound was higher in flexibility than the silica particles by measuring the compression recovery rate of the insulating particles. did.

  Moreover, in the conductive particles with insulating particles of Examples 1 to 4, it was confirmed that the polymer compound was not attached to a portion other than the portion to which the insulating particles were attached on the surface of the conductive particles. . In Example 5, since the physical / mechanical hybridization method is used, there is a portion where the polymer compound is attached to a portion other than the portion where the insulating particles are attached on the surface of the conductive particles. It was.

(Example 6)
Into a mixed solution of 25 g of pure water and 25 g of ethanol, 10 parts by weight of conductive particles with insulating particles and 0.5 part by weight of monohexyl phosphate are added before forming the coating film obtained in Example 1. , And stirred at 50 ° C. for 1 hour. Then, it filtered and it was made to dry at 100 degreeC with a vacuum dryer for 8 hours, and the electroconductive particle with an insulating particle provided with the film formed with the said monohexyl phosphate ester was obtained. The coating covered the surface of the conductive particles and the surface of the insulating particles. The coating portion covering the surface of the conductive particles and the coating portion covering the surface of the insulating particles were continuous.

(Example 7)
Conductive particles with insulating particles having a coating film were obtained in the same manner as in Example 6 except that the monohexyl phosphate was changed to monooctyl phosphate.

(Example 8)
Conductive particles with insulating particles provided with a coating were obtained in the same manner as in Example 6 except that the monohexyl phosphate was changed to hexyltriethoxysilane.

(Evaluation of Examples 6-8)
(1) Evaluation of Phosphorus Element or Silicon Element Content in Conductive Particles with Insulating Particles 1 part by weight of conductive particles with insulating particles of Examples 6 to 8 was added to a 5 wt% aqueous citric acid solution (5 wt% A solution obtained by dissolving citric acid in 95% by weight of water) was added to 100 parts by weight, stirred at 40 ° C. for 30 minutes to obtain a treatment liquid, and then the treatment liquid was filtered through a filter paper to obtain a filtrate. In the conductive particles with insulating particles in Examples 6 to 8, after the treatment with the citric acid aqueous solution, the conductive particles with the insulating particles excluding the coating adhered to the surface of the conductive particles (conductive particles or insulating particles). The coating was peeled off.

  The content of phosphorus element or silicon element in the obtained filtrate was measured using an ICP emission analyzer (“ULTIMA2” manufactured by Horiba, Ltd.).

(2) Preparation of connection structure The connection structure was obtained like evaluation of Examples 1-5 and Comparative Examples 1-3.

(3) Conductivity evaluation (between upper and lower electrodes)
Conductivity evaluation was performed in the same manner as in the evaluation of Examples 1 to 5 and Comparative Examples 1 to 3.

(4) Insulation evaluation (between adjacent electrodes in the horizontal direction)
Insulation evaluation was performed in the same manner as in the evaluation of Examples 1 to 5 and Comparative Examples 1 to 3.

(5) Rust prevention evaluation The connection structure produced by the above-mentioned insulation evaluation was left under conditions of 85 ° C. and relative humidity 85%. After 100 hours from the start of standing, the connection resistance between the electrodes was measured by the 4-terminal method in the same manner as described above. When the average connection resistance (after leaving) is less than 150% compared to the average value of the connection resistance (before leaving) at the time of the above continuity evaluation, “○” indicates that the average value of the connection resistance (after leaving) is The case where it rose 150% or more was determined as “x”.

  The results are shown in Table 2 below. Table 2 below shows specific gravity A of the conductive particles with insulating particles, specific gravity B of the conductive particles, and specific gravity C of the insulating particles.

  In addition, as a result of measuring the viscosity of the anisotropic conductive paste obtained in Examples 1 to 8 under the conditions of 25 ° C. and 2.5 rpm using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.), Example The viscosities of 1 to 8 anisotropic conductive pastes were all over 200 Pa · s and 1000 Pa · s or less.

DESCRIPTION OF SYMBOLS 1 ... Conductive particle with insulating particle 2 ... Conductive particle 3 ... Insulating particle 5 ... Insulating particle main body 6 ... Layer 11 ... Base particle 12 ... Conductive part 21 ... Conductive particle with insulating particle 22 ... Conductive Particle 31 ... Conductive part 32 ... Core substance 33 ... Protrusion 41 ... Conductive particle with insulating particle 42 ... Conductive particle 43 ... Insulating particle 51 ... Conductive part 52 ... Protrusion 61 ... Conductive particle with insulating particle 62 ... Coating DESCRIPTION OF SYMBOLS 81 ... Connection structure 82 ... 1st connection object member 82a ... Upper surface 82b ... Electrode 83 ... 2nd connection object member 83a ... Lower surface 83b ... Electrode 84 ... Connection part

When the laminate is heated and pressed, the insulating particles 3 existing between the conductive particles 2 and the electrodes 82b and 83b can be eliminated. For example, during the heating and pressurization, the insulating particles 3 existing between the conductive particles 2 and the electrodes 82b and 83b are melted or deformed, so that the surface of the conductive particles 2 Is partially exposed. At the time of the heating and pressurization, a large force is applied, by peeling a part of the insulating particles 3 from the surface of the conductive particles 2, the surface of the conductive particles 2 partially exposed Sometimes. The portion where the surface of the conductive particle 2 is exposed contacts the electrodes 82b and 83b, whereby the electrodes 82b and 83b can be electrically connected via the conductive particle 2 .

Claims (14)

Conductive particles having at least a conductive portion on the surface;
A plurality of insulating particles attached to the surface of the conductive particles,
The specific gravity ratio of the specific gravity of the conductive particles with insulating particles to the specific gravity of the conductive particles is less than 0.97,
Conductive particles with insulating particles, wherein the specific gravity of the conductive particles is 2.0 or more and 3.5 or less.   The conductive particles with insulating particles according to claim 1, wherein the specific gravity ratio of the specific gravity of the conductive particles with insulating particles to the specific gravity of the conductive particles is less than 0.95.   The conductive particles with insulating particles according to claim 1 or 2, wherein a coverage, which is an area of a portion covered with the insulating particles occupying the entire surface area of the conductive particles, is 40% or more.   The conductive particles with insulating particles according to claim 3, wherein the coverage, which is the area of the portion covered with the insulating particles occupying the entire surface area of the conductive particles, is 60% or more. When the conductive particle-containing liquid with insulating particles obtained by adding 3 parts by weight of conductive particles with insulating particles to 100 parts by weight of ethanol was subjected to ultrasonic treatment for 5 minutes at 20 ° C. and 40 kHz, the following formula (1) The conductive particles with insulating particles according to any one of claims 1 to 4, wherein the residual ratio of the insulating particles obtained by the method is 60% or more and 95% or less.
Residual ratio of insulating particles (%) = (coverage ratio after sonication / coverage ratio before sonication) × 100 (1)   The conductive particles with insulating particles according to claim 1, wherein the specific gravity of the insulating particles is 1.0 or more and 2.0 or less.   The electroconductive particle with an insulating particle of any one of Claims 1-6 further provided with the film which has coat | covered the surface of the said electroconductive particle.   The conductive particles with insulating particles according to claim 7, wherein the coating covers the surface of the conductive particles and the surface of the insulating particles.   The conductive particles with insulating particles according to claim 7 or 8, wherein the coating is formed of a compound having an alkyl group having 6 to 22 carbon atoms.   The conductive particles with insulating particles according to any one of claims 1 to 9, which are conductive particles with insulating particles used in a paste-like anisotropic conductive paste.   The conductive particles with insulating particles according to claim 1, wherein the conductive particles have base particles and a conductive layer disposed on a surface of the base particles.   The anisotropic conductive material containing the electroconductive particle with an insulating particle of any one of Claims 1-11, and binder resin.   The anisotropic conductive material according to claim 12, which is a paste-like anisotropic conductive paste. A first connection target member, a second connection target member, and a connection part connecting the first and second connection target members;
The said connection part is formed by the electroconductive particle with an insulating particle of any one of Claims 1-11, or anisotropic conductivity containing this electroconductive particle with an insulating particle and binder resin. A connection structure made of a material.

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