JP2011060502A - Conductive particle with insulating particles, anisotropic conductive material, and connection structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive particle with insulating particles capable of increasing the conduction reliability in electrically connecting electrodes with each other. <P>SOLUTION: The conductive particles 1 with insulating particles, each include: a conductive particle 2 having a polymer particle 4 and a conductive layer 5 covering a surface 4a of the polymer particle 4; and the insulating particles 3 attached to the surface 2a of the conductive particle 2. The polymer particles 4 are obtained by polymerizing at least two monomers which are alicyclic compounds having ring structures. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to, for example, conductive particles with insulating particles that can be used for electrical connection between electrodes, and an anisotropic conductive material and a connection structure using the conductive particles with insulating particles.

  As anisotropic conductive materials, anisotropic conductive pastes, anisotropic conductive inks, anisotropic conductive adhesives, anisotropic conductive films, anisotropic conductive sheets, and the like are widely known. In these anisotropic conductive materials, conductive particles are dispersed in paste, ink, or resin.

As an example of the conductive particles, Patent Document 1 below discloses conductive particles having base particles and a conductive layer formed on the surface of the base particles. In order to form the base particles, a divinylbenzene-ethylvinylbenzene mixture is used as a part of the monomer. This conductive particle has a compressive elastic modulus of 2.5 × 10 ⁹ N / m ² or less when 10% of the particle diameter is displaced, a compression deformation recovery rate of 30% or more, and a fracture strain of 30% or more. is there.

  Patent Document 2 below includes coated conductive particles comprising conductive particles having a polar group on at least a part of the surface and an insulating material covering at least a part of the surface of the conductive particles. Is disclosed. The insulating material includes a polar group on the surface of conductive particles, a polymer electrolyte that can be adsorbed, and inorganic particles that can be adsorbed to the polymer electrolyte. These inorganic particles are insulating particles. The coated conductive particles can be obtained, for example, by electrostatically adsorbing the polymer electrolyte on at least a part of the surface of the conductive particles, and further electrostatically adsorbing the inorganic particles.

JP 2003-313304 A JP 2008-120990 A

  In the conductive particles described in Patent Document 1, insulating particles are not attached to the surface of the conductive particles. For this reason, when a plurality of conductive particles are in contact, adjacent electrodes that should not be connected, not between the upper and lower electrodes, may be connected by the plurality of contacted conductive particles.

  In recent years, with the miniaturization of electronic devices, it has been studied to thin a flexible printed circuit board provided with electrodes. For example, a two-layer flexible printed board in which electrodes are directly provided on a polyimide film is used.

  When the electrodes of the two-layer flexible printed board and the glass substrate are connected using an anisotropic conductive material containing the conductive particles or the coated conductive particles, the connection resistance value between the electrodes may be increased. In the two-layer flexible printed board, since the anisotropic conductive material is directly bonded to the polyimide film, the adhesive force of the anisotropic conductive material tends to be low.

  Furthermore, when the electrodes are connected by the anisotropic conductive material, since the compression deformation recovery rate of the conductive particles is high, the anisotropic conductive material may be peeled off due to the repulsive force of the conductive particles. For this reason, the connection resistance value between electrodes may not be made sufficiently low.

  When connecting the electrodes of the two-layer flexible printed circuit board and the glass substrate, after placing an anisotropic conductive material on the substrate, another substrate is placed on the substrate so that the electrodes face each other. Overlapping. Next, the conductive particles are compressed by pressurization to connect the electrodes. At this time, there may be a case where indentations generated when pressure is applied to the electrodes in contact with the conductive particles or the coated conductive particles are not sufficiently formed. In addition, voids may be generated around the conductive particles or the coated conductive particles. For this reason, the conductive reliability between the electrodes of the two-layer flexible printed board and the glass substrate may be low.

  Further, when the electrodes are connected by an anisotropic conductive material including the coated conductive particles described in Patent Document 2, the area of the contact portion between the electrode and the coated conductive particle is small, so that the insulating particles are sandwiched between the contact portions. As a result, the connection resistance between the electrodes may increase. For this reason, the conduction | electrical_connection reliability between electrodes may be low.

  An object of the present invention is to provide conductive particles with insulating particles that can enhance the conductive reliability when the electrodes are electrically connected, and an anisotropic conductive material and a connection structure using the conductive particles. Is to provide.

  A limited object of the present invention is to provide an insulating particle capable of forming an indentation on an electrode in contact with a conductive particle when an electrode between a flexible printed circuit board such as a two-layer flexible printed circuit board and a glass substrate is electrically connected. It is an object to provide conductive particles, a method for producing the same, and an anisotropic conductive material and a connection structure using the conductive particles.

  According to a wide aspect of the present invention, there are provided polymer particles, conductive particles having a conductive layer covering the surface of the polymer particles, and insulating particles attached to the surface of the conductive particles. There is provided conductive particles with insulating particles, wherein the polymer particles are polymer particles obtained by polymerizing a monomer that is an alicyclic compound having at least two ring structures.

  In a specific aspect of the conductive particle with insulating particles according to the present invention, the at least two ring structures are a bicyclo ring structure or a tricyclo ring structure.

  In another specific aspect of the conductive particle with insulating particles according to the present invention, the monomer is an acrylic monomer.

  In another specific aspect of the conductive particles with insulating particles according to the present invention, the polymer particles are obtained by polymerizing a monofunctional monomer that is an alicyclic compound having at least two ring structures and a polyfunctional monomer. It is the polymer particle obtained by this.

  In still another specific aspect of the conductive particle with insulating particles according to the present invention, the polymer particle is a polymer obtained by polymerizing a polyfunctional monomer that is an alicyclic compound having at least two ring structures. It is a coalesced particle.

  In another specific aspect of the conductive particle with insulating particles according to the present invention, the polymer particle includes a monofunctional monomer that is an alicyclic compound having at least two ring structures, and a fat having at least two ring structures. It is a polymer particle obtained by polymerizing a polyfunctional monomer which is a cyclic compound.

  In still another specific aspect of the conductive particles with insulating particles according to the present invention, the outer surface of the conductive layer is a conductive layer containing nickel, a conductive layer containing palladium, or a conductive layer containing a low melting point metal.

  In another specific aspect of the conductive particles with insulating particles according to the present invention, the insulating particles have a hydroxyl group directly bonded to a phosphorus atom or a hydroxyl group directly bonded to a silicon atom on the surface.

  The anisotropic conductive material according to the present invention includes conductive particles with insulating particles configured according to the present invention and a binder resin.

  The connection structure according to the present invention includes a first connection target member, a second connection target member, and a connection portion connecting the first and second connection target members, and the connection portion is a main connection member. The conductive particles with insulating particles constituted according to the invention, or the anisotropic conductive material containing the conductive particles with insulating particles and a binder resin.

  In the conductive particles with insulating particles according to the present invention, the insulating particles are attached to the surface of the conductive particles, so that even if a plurality of conductive particles with insulating particles come into contact with each other, insulation between adjacent conductive particles is performed. There are particles. For this reason, it is difficult to electrically connect adjacent electrodes that should not be connected, not between the upper and lower electrodes.

  Furthermore, in the present invention, since polymer particles obtained by polymerizing a monomer that is an alicyclic compound having at least two ring structures are used, when the electrodes are electrically connected, the conductivity is increased. The contact area between the particles and the electrode can be increased, and the conduction reliability can be increased. Since the contact area between the conductive particles and the electrode can be increased, even if a small amount of insulating particles remain between the conductive particles and the electrode, other areas around the portion where the insulating particles remain It is possible to conduct in the part. For this reason, the connection resistance value between electrodes can be made low.

  Further, when the conductive particles with insulating particles using the polymer particles are used to connect the electrodes of the printed circuit board and the glass substrate, the conductive particles are attached to the electrodes of the printed circuit board or the glass substrate. The indentation which contacted becomes easy to be formed. For this reason, the conduction | electrical_connection reliability between the electrodes of a printed circuit board and a glass substrate can be improved. In particular, when the printed circuit board is a two-layer flexible printed circuit board, the conduction reliability between the electrodes can be enhanced.

FIG. 1 is a cross-sectional view showing conductive particles with insulating particles according to an embodiment of the present invention. FIG. 2 is a front cross-sectional view schematically showing a connection structure using conductive particles with insulating particles according to an embodiment of the present invention. FIG. 3 is an enlarged front sectional view showing a contact portion between the conductive particles with insulating particles and the electrodes of the connection structure shown in FIG. FIG. 4 is an enlarged front sectional view showing another example of the contact portion between the conductive particles with insulating particles and the electrodes of the connection structure shown in FIG. FIG. 5 is an enlarged front sectional view showing a contact portion between conductive particles with insulating particles and electrodes in a conventional connection structure using conductive particles with insulating particles.

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

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

  As shown in FIG. 1, the conductive particles 1 with insulating particles include conductive particles 2 and a plurality of insulating particles 3 attached to the surface 2 a of the conductive particles 2.

  The conductive particles 2 include polymer particles 4 and a conductive layer 5 that covers the surface 4 a of the polymer particles 4. The conductive particle 2 is a coated particle in which the surface 4 a of the polymer particle 4 is coated with the conductive layer 5. Accordingly, the conductive particles 2 have the conductive layer 5 on the surface 2a. The insulating particles 3 are made of an insulating material.

  The polymer particle 4 is obtained by polymerizing a monomer that is an alicyclic compound having at least two ring structures. The alicyclic compound having at least two ring structures is preferably a polycyclic compound.

  Examples of the at least two ring structures include a bicyclo ring structure, a tricyclo ring structure, a spiro ring structure, and a dispiro ring structure. Among these, the at least two ring structures are preferably a bicyclo ring structure or a tricyclo ring structure. In the case of a bicyclo ring structure or a tricyclo ring structure, the compression recovery rate of the polymer particles 4 can be lowered. For this reason, when the electrodes of the printed circuit board such as the two-layer flexible printed circuit board and the glass substrate are connected by the anisotropic conductive material including the conductive particles with insulating particles 1 using the polymer particles 4, the conductivity is increased. Due to the repulsive force of the particles 2, the anisotropic conductive material becomes difficult to peel off. Furthermore, indentations are likely to be formed on the electrodes in contact with the conductive particles 2. The indentation formed on the electrode is a concave portion of the electrode formed by the conductive particles 2 pushing the electrode. Since the conductive particles 2 are generally spherical, the recesses of the electrode are generally hemispherical. In addition, voids are less likely to occur around the conductive particles 2. In addition, the said space | gap arises when an adhesive layer etc. interface peel from the connection object members, such as a board | substrate or an electrode. The voids are preferably not generated. However, the gap may be generated to such an extent that the conductive reliability is not affected.

  The monomer is not particularly limited as long as it is an alicyclic compound having at least two ring structures. Examples of the monomer include acrylic monomers, vinyl ether compounds, epoxy compounds, and isocyanate compounds. Especially, since the compression recovery rate of the polymer particle 4 can be made low, an acrylic monomer is preferable.

  Specific examples of the acrylic monomer include dimethylol-tricyclodecane di (meth) acrylate, 1,3-adamantanediol di (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and dicyclohexane. Examples include pentanyl (meth) acrylate, 2-methyl-2-adamantyl (meth) acrylate, 2-ethyl-2-adamantyl (meth) acrylate, and 3-hydroxy-1-adamantyl (meth) acrylate. In addition, (meth) acrylate means a methacrylate or an acrylate.

  Specific examples of the vinyl ether compound include tricyclodecane vinyl ether and tricyclodecane monomethyl vinyl ether.

  As the monomer component, in addition to the monomer that is an alicyclic compound having at least two ring structures, another monomer other than the monomer may be used. The content of the monomer that is an alicyclic compound having at least two ring structures in 100% by weight of the monomer component is preferably 5% by weight or more, and more preferably 20% by weight or more. Examples of the other monomer include styrene and divinylbenzene. Furthermore, as the other monomer, polytetramethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) ) Acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ethylene glycol (meth) acrylate, trifluoroethyl (meth) acrylate, pentafluoropropyl (meth) Examples include acrylate or cyclohexyl (meth) acrylate.

  When a monofunctional acrylic monomer that is an alicyclic compound having at least two ring structures is used, the content of the monofunctional acrylic monomer is in the range of 40 to 60% by weight in 100% by weight of the monomer component. Is preferred. Monofunctional acrylic monomers include isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, 2-methyl-2-adamantyl (meth) acrylate, 2-ethyl-2-adamantyl ( (Meth) acrylate or 3-hydroxy-1-adamantyl (meth) acrylate is preferably used.

  When a bifunctional acrylic monomer that is an alicyclic compound having at least two ring structures is used, the content of the bifunctional acrylic monomer is in the range of 20 to 80% by weight in 100% by weight of the monomer component. Is preferred. As the bifunctional acrylic monomer, dimethylol-tricyclodecane di (meth) acrylate or 1,3-adamantanediol di (meth) acrylate is preferably used.

  The polymer particle 4 was obtained by polymerizing a monofunctional monomer (hereinafter sometimes abbreviated as a monofunctional monomer A) which is an alicyclic compound having at least two ring structures and a polyfunctional monomer. Polymer particles are preferred. The monomer component preferably includes the monofunctional monomer A and a polyfunctional monomer. Examples of the polyfunctional monomer include aromatic compounds having at least two vinyl groups or polyfunctional acrylic monomers. Examples of the aromatic compound include 1,2-divinylbenzene, 1,3-divinylbenzene, 1,4-divinylbenzene, and the like. As the aromatic compound, “DVB960” manufactured by Nippon Steel Chemical Co., Ltd. is commercially available. The polyfunctional acrylic monomer is preferably a polyfunctional acrylic monomer having a-(R-O) n- unit, such as polytetramethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethanetri. Examples include (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, triethylene glycol di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like. In addition, said R is a C1-C9 alkylene group, and said n is an integer greater than or equal to 1.

  When the monofunctional monomer A and the polyfunctional monomer are polymerized, the 10% K value is relatively high and the 10% K value is controlled within a suitable range as compared with the case where only the monofunctional monomer A is polymerized. And the compression recovery rate can be increased. That is, by using a polyfunctional monomer as a crosslinking agent together with the monofunctional monomer A, the 10% K value and the compression recovery rate can be controlled.

  The monomer component preferably contains 20 to 90% by weight of the monofunctional monomer A and 10 to 80% by weight of the polyfunctional monomer. In this case, polymer particles having a 10% K value and a favorable compression recovery rate can be easily obtained. The monomer component preferably includes 20 to 80% by weight of the monofunctional monomer A and 20 to 80% by weight of the polyfunctional monomer, and further includes 40 to 60% by weight of the monofunctional monomer A and 40 to 60% by weight of the polyfunctional monomer. % Is more preferable.

  The polymer particles 4 are preferably polymer particles obtained from a polyfunctional monomer that is an alicyclic compound having at least two ring structures (hereinafter sometimes abbreviated as polyfunctional monomer B). The monomer component preferably contains the polyfunctional monomer B. Even if only the polyfunctional monomer B is polymerized, the 10% K value can be made relatively high, the 10% K value can be controlled within a suitable range, and the compression recovery rate can be made relatively high. However, other monomers may be used together with the polyfunctional monomer B.

  The monomer component preferably contains 20% by weight or more of the polyfunctional monomer B. When the content of the polyfunctional monomer B is 20% by weight or more, the 10% K value can be increased and the 10% K value can be controlled within a suitable range without the polymer particles becoming too flexible. Further, when the polyfunctional monomer B and an acrylic monomer such as polytetramethylene glycol di (meth) acrylate having two functional groups are used in combination, the 10% K value can be controlled within a suitable range. Further, when the polyfunctional monomer B and a vinyl monomer such as divinylbenzene having an aromatic ring and at least two functional groups are used in combination, the 10% K value and the compression recovery rate can be increased. The more preferable lower limit of the content of the polyfunctional monomer B in 100% by weight of the monomer component is 20% by weight, the preferable upper limit is 80% by weight, and the more preferable upper limit is 60% by weight. The content of the polyfunctional monomer B in 100% by weight of the monomer component may be 100% by weight.

  The other monomer used in combination with the polyfunctional monomer B may be a monofunctional monomer A that is an alicyclic compound having at least two ring structures. By the combined use of the monofunctional monomer A and the polyfunctional monomer B, the 10% K value and the compression recovery rate can be controlled within suitable ranges.

  The polymerization method is not particularly limited. Specific examples of the polymerization method include conventionally known polymerization methods such as a suspension polymerization method, an emulsion polymerization method, a seed polymerization method, and a dispersion polymerization method.

  Since the particle size distribution is relatively wide and polydisperse polymer particles can be obtained, the suspension polymerization method and the emulsion polymerization method are suitable for the purpose of producing fine particles having a variety of particle sizes. When the suspension polymerization method and the emulsion polymerization method are used, it is preferable to classify polymer particles obtained by polymerization and select polymer particles having a desired particle size or particle size distribution.

  In addition, since no monodisperse polymer particles can be obtained without classification, the seed polymerization method is suitable for the purpose of producing a large amount of polymer particles having a specific particle size. The seed polymerization method is a method in which seed particles such as styrene polymer particles are swollen with a monomer that is an alicyclic compound having at least two ring structures and polymerized. Therefore, when the polymer particles are produced by the seed polymerization method, the polymer particles may contain a component constituting the seed particles. For example, when styrene polymer particles are used as seed particles, the resulting polymer particles may contain a styrene polymer.

  The solvent used for the polymerization is not particularly limited. The solvent is appropriately selected according to the monomer component. Examples of the solvent include water, alcohol, cellosolve, ketone, and acetate. Other solvents other than these solvents may be used. Specific examples of the alcohol include methanol, ethanol, and propanol. Specific examples of the cellosolve include methyl cellosolve and ethyl cellosolve. Specific examples of the ketone include acetone, methyl ethyl ketone, methyl butyl ketone, and 2-butanone. Specific examples of the acetate include ethyl acetate and butyl acetate. Specific examples of the other solvent include acetonitrile, N, N-dimethylformamide, dimethyl sulfoxide and the like. As for these solvents, only 1 type may be used and 2 or more types may be used together.

  The average particle diameter of the polymer particles 4 is preferably in the range of 0.1 to 1,000 μm. A more preferable lower limit of the average particle diameter of the polymer particles 4 is 1 μm, a further preferable lower limit is 1.5 μm, and a particularly preferable lower limit is 2 μm. A more preferable upper limit of the average particle diameter of the polymer particles 4 is 500 μm, a further preferable upper limit is 300 μm, and a particularly preferable upper limit is 30 μm. If the average particle diameter is too small, the contact area between the conductive particles 2 and the electrode is small, and the connection resistance value may be high. Further, when the conductive layer 5 is formed on the surface 4a of the polymer particle 4 by electroless plating, the aggregated conductive particles 2 are easily formed. If the average particle diameter is too large, the conductive particles 2 are not sufficiently compressed, and the connection resistance value between the electrodes may be increased.

  The average particle diameter is a number average particle diameter. The average particle diameter can be measured using, for example, a Coulter counter (manufactured by Beckman Coulter).

  The polymer particle 4 has a CV value (variation coefficient of particle size distribution) of preferably 10% or less, and more preferably 3% or less. If the CV value exceeds 10%, the spacing between the electrodes connected by the conductive particles 2 may vary.

  The CV value is represented by the following formula.

CV value (%) = (ρ / Dn) × 100
ρ: standard deviation of polymer particle diameter Dn: average particle diameter

  The compression recovery rate of the polymer particles 4 is preferably 50% or less, and more preferably 40% or less. If the compression recovery rate exceeds 50%, the anisotropic conductive material may peel from the substrate or the like due to the repulsive force of the conductive particles used for connection between the electrodes. As a result, the connection resistance value between the electrodes may increase. The compression recovery rate of the polymer particles 4 is preferably 5% or more, more preferably 10% or more, and even more preferably 20% or more.

  The compression recovery rate can be measured as follows.

  The polymer particles are dispersed on the sample stage. For one dispersed polymer particle, a load is applied up to the reversal load value (5.00 mN) in the center direction of the polymer particle using a micro compression tester. Thereafter, the load is gradually reduced to the load value for origin (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 (%) = [(L ₁ −L ₂ ) / L ₁ ] × 100
L ₁ : Compressive displacement from the load value for the origin when the load is applied to the reverse load value L ₂ : Compressive displacement from the reverse load value when the load is released to the load value for the origin

The compression modulus (10% K value) when the diameter of the polymer particles 4 is displaced by 10% is preferably in the range of 196 to 6,860 N / mm ² . A more preferable lower limit of the 10% K value is 980 N / mm ² , and a more preferable upper limit is 4,900 N / mm ² . The compression modulus (20% K value) when the diameter of the polymer particles is displaced by 20% is preferably in the range of 196 to 6,860 N / mm ² . A more preferable lower limit of the 20% K value is 600 N / mm ² , a further preferable lower limit is 980 N / mm ² , a more preferable upper limit is 4,900 N / mm ² , and a further preferable upper limit is 3,900 N / mm ^2. It is. The compression elastic modulus (30% K value) when the diameter of the polymer particles is displaced by 30% is preferably in the range of 196 to 6,860 N / mm ² . A more preferable lower limit of the 30% K value is 600 N / mm ² , a further preferable lower limit is 980 N / mm ² , and a more preferable upper limit is 4,900 N / mm ² .

  If the compression modulus (10% K value, 20% K value, and 30% K value) is too low, the polymer particles may be destroyed when compressed. If the compression modulus (10% K value, 20% K value, and 30% K value) is too high, the connection resistance value between the electrodes may increase.

  The compression elastic modulus (10% K value, 20% K value, and 30% K value) can be measured as follows.

  Using a micro-compression tester, polymer particles are compressed under the conditions of a compression speed of 2.6 mN / sec and a maximum test load of 10 g with 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.

K value (N / mm ² ) = (3/2 ^1/2 ) · F · S ⁻³ / ² · R ^−1/2
F: Load value (N) when the polymer particles are 10%, 20% or 30% compressively deformed
S: Compression displacement (mm) when the polymer particles are 10%, 20% or 30% compressively deformed
R: radius of polymer particles (mm)

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

  The metal constituting the conductive layer 5 is not particularly limited. Examples of the metal include gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium, cadmium, palladium, tin-lead alloy, tin -Copper alloy, tin-silver alloy, tin-lead-silver alloy, etc. are mentioned. Especially, it is preferable that the metal which comprises the conductive layer 5 is nickel, copper, palladium, or gold | metal | money.

  The method for forming the conductive layer 5 on the surface 4a of the polymer particle 4 is not particularly limited. Examples of the method for forming the conductive layer 5 include methods such as electroless plating, electroplating, and sputtering. Especially, it is preferable that the method of forming the conductive layer 5 on the surface 4a of the polymer particle 4 is a method of forming by electroless plating.

  The outer surface of the conductive layer 5 of the conductive particles 2 is preferably a gold layer, a nickel layer, or a palladium layer, and is preferably a nickel layer or a palladium layer. Furthermore, the conductive layer 5 is preferably formed of a nickel layer and a palladium layer laminated on the surface of the nickel layer. By forming these preferable conductive layers, the connection resistance value between the electrodes connected by the conductive particles 2 is lowered. Further, when the outer surface of the conductive layer 5 is a nickel layer or a palladium layer, the metal oxide covering the electrode surface can be easily removed when the conductive particles 2 are brought into contact with the electrode. For this reason, the outer surface of the conductive layer 5 and the metal on the electrode surface easily come into contact with each other, and the connection resistance value is lowered.

  The outer surface of the conductive layer 5 is preferably a conductive layer containing nickel, a conductive layer containing palladium, or a conductive layer containing a low-melting-point metal. When the outer surface of the conductive layer 5 is a metal layer containing nickel or a conductive layer containing palladium, the metal oxide covering the electrode surface can be easily removed, and the outer surface of the conductive layer 5 Since the metal on the electrode surface is easily contacted, the connection resistance value is lowered. When the outer surface of the conductive layer 5 is a conductive layer containing a low-melting-point metal, the conductive layer containing the low-melting-point metal and the electrode are brought into surface contact instead of point contact by reflow, so that the connection resistance value is lowered. . Furthermore, when the connection target member is electrically connected using the conductive particles 1 with insulating particles, the low melting point metal layer is hardly cracked even if an impact such as dropping is applied.

  The conductive layer may be a single layer or may have a stacked structure of two or more layers. As the conductive layer in the case where the conductive layer has a laminated structure of two layers, the inner layer / outer layer may be a nickel layer / gold layer, a nickel layer / palladium layer, or a copper layer / low melting point metal layer.

  As a low melting point metal layer, that is, a conductive layer containing a low melting point metal, a conductive layer containing tin, a conductive layer containing tin and silver, a conductive layer containing tin and copper, a conductive layer containing tin, silver and copper, or Examples thereof include a conductive layer containing tin, silver and nickel. The low melting point metal is a metal having a melting point of 300 ° C. or lower. Further, in 100% by weight of the metal contained in the conductive layer containing the low melting point metal, tin is preferably contained in an amount of 50% by weight or more, more preferably 70% by weight or more, and more preferably 90% by weight or more. Is more preferable.

  When the outer surface of the conductive layer 5 covering the surface 4a of the polymer particle 4 is a low melting point metal layer, stress applied to the conductive particle 2 can be relieved, so that the electrodes can be easily connected.

  When the connection target member is electrically connected by the conductive particles 1 with insulating particles using the conductive particles 2 in which the low melting point metal layer is formed on the outer surface of the conductive layer 5, an impact is applied by dropping or the like. However, cracks are unlikely to occur in the low melting point metal layer. For this reason, electrical conductivity reliability can be improved.

  The thickness of the conductive layer 5 is preferably in the range of 5 to 70,000 nm. A more preferable lower limit of the thickness of the conductive layer 5 is 10 nm, a further preferable lower limit is 20 nm, a more preferable upper limit is 40,000 nm, a more preferable upper limit is 500 nm, and a further preferable upper limit is 200 nm. If the thickness of the conductive layer 5 is too thin, sufficient conductivity may not be obtained. If the thickness of the conductive layer 5 is too thick, the difference in coefficient of thermal expansion between the polymer particles 4 and the conductive layer 5 becomes large, and the conductive layer 5 may be easily peeled off from the polymer particles 4. When the conductive layer 5 has a laminated structure, the thickness of the conductive layer 5 indicates the total thickness of each conductive layer.

  The compression recovery rate of the conductive particles 2 is preferably 50% or less, preferably 45% or less, and more preferably 40% or less. If the compression recovery rate exceeds 50%, the anisotropic conductive material may peel from the substrate or the like due to the repulsive force of the conductive particles used for connection between the electrodes. As a result, the connection resistance value between the electrodes may increase. When the compression recovery rate of the conductive particles 2 is 45% or less, the connection resistance value between the electrodes can be further reduced. The compression recovery rate of the conductive particles 2 is preferably 5% or more, more preferably 10% or more, and even more preferably 20% or more.

  The insulating particles 3 are particles having insulating properties. The insulating particles 3 are smaller than the conductive particles 2.

  Examples of the material constituting the insulating particles 3 include an insulating resin and an insulating inorganic substance. Examples of the insulating resin include polyolefin resin, acrylic resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide, polyacetal, Examples include polyimide, polyamideimide, polyetheretherketone, and polyethersulfone. Examples of the insulating inorganic material include silica and carbon black.

  A method for attaching the insulating particles 3 to the conductive particles 2 is not particularly limited. Examples include a method of attaching by chemical bonding, a method of attaching by spray drying or hybridization as described in JP-A-7-105716, a method of attaching by electrostatic action, and a method of attaching by vacuum deposition. As a method of attaching by the chemical bond, for example, a functional group is introduced into the surface 3a of the insulating particle 3 or the surface 2a of the conductive particle 2, and the insulating particle 3 is attached to the surface of the conductive particle 2 through the functional group. The method of making it adhere, etc. are mentioned.

  The functional group is preferably a thiol group or a sulfide group. In this case, the adhesion between the insulating particles 3 and the conductive particles 2 can be further enhanced.

  Since the adhesion between the conductive particles 2 and the insulating particles 3 can be further enhanced, the insulating particles 3 are directly bonded to a hydroxyl group bonded to a phosphorus atom (hereinafter also referred to as a P—OH group) or a silicon atom. It is preferable to have a hydroxyl group (hereinafter also referred to as Si—OH group) formed on the surface 3a. Especially, since the adhesiveness of the electroconductive particle 2 and the insulating particle 3 can further be improved, it is preferable that the insulating particle 3 has the said P-OH group in the surface 3a.

  For example, the conductive particles 1 with insulating particles can be obtained by attaching the insulating particles 3 having a hydroxyl group directly bonded to a phosphorus atom or a hydroxyl group directly bonded to a silicon atom to the surface 2 a of the conductive particle 2. Obtainable. In the conductive particles 1 with insulating particles, the insulating particles 3 are attached to the surface 2a of the conductive particles 2 by the P—OH group or the Si—OH group, for example.

  The P—OH group or the Si—OH group on the surface 3 a of the insulating particle 3 is strongly chemically bonded to the conductive layer 5 on the surface 2 a of the conductive particle 2. Such a bond has a very high bond strength compared to a bond by van der Waals force or electrostatic force alone. Therefore, the conductive particles 2 and the insulating particles 3 can be firmly attached, and the insulating particles 3 can be prevented from being detached from the surface 2 a of the conductive particles 2. For example, when the conductive particles 1 with insulating particles are added to a binder resin or the like and kneaded, the insulating particles 3 are not easily detached from the surface 2 a of the conductive particles 2. In addition, when a plurality of conductive particles 1 with insulating particles are in contact, the insulating particles 3 are unlikely to be detached from the surface 2 a of the conductive particles 2 due to an impact at the time of contact.

  The plurality of insulating particles 3 having the P—OH group or the Si—OH group on the surface 3a are not chemically bonded to each other by the P—OH group or the Si—OH group. For this reason, the insulating particles 3 can be attached to the surface 2a of the conductive particles 2 so as to form a single layer rather than two or more layers. Accordingly, it is possible to obtain conductive particles 1 with insulating particles having a uniform particle size.

  Further, when the insulating particle 3 has the P—OH group or the Si—OH group on the surface 3a, the conductive layer 5 or the electrode is hardly corroded by the P—OH group or the Si—OH group. For example, when the insulating particles have a group containing a sulfur atom on the surface, the conductive layer 5 or the electrode may be corroded by the group containing a sulfur atom. When the insulating particle 3 has the P—OH group or the Si—OH group on the surface 3a, corrosion of the conductive layer 5 or the electrode can be suppressed.

  The insulating particle 3 preferably has a group represented by the following formula (11) or a hydroxyl group directly bonded to a silicon atom on the surface 3a. That is, the insulating particles having the P—OH group on the surface preferably have a group represented by the following formula (11) on the surface. In this case, the insulating particles 3 are more difficult to be detached from the surface 2 a of the conductive particles 2.

  In said formula (11), X1 represents a hydroxyl group, an alkoxy group, or a C1-C12 alkyl group.

  The group represented by the above formula (11) is preferably a group represented by the following formula (11A). In this case, the adhesion of the insulating particles 3 to the conductive particles 2 can be further enhanced.

  Moreover, it is preferable that the insulating particle which has the said Si-OH group on the surface has group represented by following formula (12) on the surface. The group represented by the following formula (12) can be relatively easily introduced into the surface 3 a of the insulating particle 3.

  In said formula (12), Z1 and Z2 respectively represent a hydroxyl group, an alkoxy group, or a C1-C12 alkyl group. Z1 and Z2 may be the same or different. Since the insulating particles 3 can be firmly attached to the surface 2a of the conductive particles 2, each of Z1 and Z2 is preferably a hydroxyl group.

  As a method for introducing the P—OH group or the Si—OH group into the surface 3 a of the insulating particle 3, a compound having a hydroxyl group directly bonded to a phosphorus atom (hereinafter also referred to as a P—OH group-containing compound) is used. Or a method of performing surface treatment with a compound having a hydroxyl group directly bonded to a silicon atom (hereinafter also referred to as a Si—OH group-containing compound), and a material constituting the insulating particle in the production of the insulating particle, Examples thereof include a method of containing the P-OH group-containing compound or the Si-OH group-containing compound. From the viewpoint of efficiently introducing the P—OH group or the Si—OH group into the surface 3 a of the insulating particle 3, the P—OH is used as a material constituting the insulating particle 3 when the insulating particle 3 is produced. A method of containing the group-containing compound or the Si—OH group-containing compound is preferable. Since the adhesion between the insulating particles 3 and the conductive particles 2 can be further enhanced, the insulating particles 3 are preferably insulating particles using the P—OH group-containing compound as a material.

  As described above, the insulating particle 3 having a hydroxyl group directly bonded to a phosphorus atom or a hydroxyl group directly bonded to a silicon atom on the surface thereof is bonded directly to a compound having a hydroxyl group directly bonded to a phosphorus atom or a silicon atom, for example. It can be obtained by using a compound having a hydroxyl group.

  As a method of surface-treating the insulating particles with the P-OH group-containing compound or the Si-OH group-containing compound, the P-OH group-containing compound or the Si-OH group-containing compound is chemically applied to the surface of the insulating particles. And the surface of the insulating particle is chemically treated, and the insulating particle has the P-OH group or the Si-OH group on the surface by the P-OH group-containing compound or the Si-OH group-containing compound. And the like.

  As said P-OH group containing compound, the compound represented by following formula (1) is mentioned.

  In said formula (1), X1 represents a hydroxyl group, an alkoxy group, or a C1-C12 alkyl group, and X2 represents the organic group containing an unsaturated bond.

  In the above formula (1), X1 is preferably a hydroxyl group. That is, the compound represented by the above formula (1) is preferably a compound represented by the following formula (1A). In this case, the adhesion between the conductive particles 2 and the insulating particles 3 can be further enhanced.

  In the above formula (1A), X2 represents an organic group containing an unsaturated bond. X2 in the above formula (1) and formula (1A) preferably contains a (meth) acryloyl group because it can be easily copolymerized with the constituent raw materials of the insulating particles.

  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.

  As said Si-OH group containing compound, the compound represented by following formula (2) is mentioned.

  In said formula (12), Z1 and Z2 respectively represent a hydroxyl group, an alkoxy group, or a C1-C12 alkyl group, and Z3 represents the organic group containing an unsaturated bond. Z1 to Z3 may be the same or different. Since the insulating particles 3 can be firmly attached to the surface 2a of the conductive particles 2, each of Z1 and Z2 is preferably a hydroxyl group. Further, Z3 preferably contains a (meth) acryloyl group because it can be easily copolymerized with the constituent material of the insulating particles.

  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.

  The particle diameter of the insulating particles 3 can be appropriately selected depending on the particle diameter of the conductive particles 2 and the use of the conductive particles 1 with insulating particles. The average particle diameter of the insulating particles 3 is preferably in the range of 0.005 to 1 μm. A more preferable lower limit of the average particle diameter of the insulating particles 3 is 0.01 μm, and a more preferable upper limit is 0.5 μm. If the average particle diameter of the insulating particles 3 is too small, the conductive particles 2 of the plurality of conductive particles 1 with insulating particles are likely to come into contact with each other when the conductive particles 1 with insulating particles are dispersed in the binder resin. If the average particle diameter of the insulating particles 3 is too large, it is necessary to increase the pressure in order to eliminate the insulating particles 3 between the electrodes and the conductive particles 2 during connection between the electrodes, You have to heat it up.

  The “average particle diameter” of the insulating particles 3 indicates the number average particle diameter. The average particle diameter of the insulating particles 3 is obtained in the same manner as the average particle diameter of the conductive particles 2.

  The average particle diameter of the insulating particles 3 is preferably 1/5 or less of the average particle diameter of the conductive particles 2. The average particle diameter of the insulating particles 3 is preferably 1/1000 or more of the average particle diameter of the conductive particles 2. When the average particle diameter of the insulating particles 3 is 1/5 or less of the average particle diameter of the conductive particles 2, for example, when the conductive particles 1 with insulating particles are manufactured, the insulating particles 3 are formed on the surface of the conductive particles 2. It can be made to adhere more efficiently by 2a.

  Two or more kinds of 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 2a of the conductive particles 2, the exposed area of the conductive particles 2 can be reduced.

(Anisotropic conductive material)
The anisotropic conductive material according to the present invention includes the conductive particles with insulating particles of the present invention and a binder resin.

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

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

  In addition to conductive particles with insulating particles and binder resin, anisotropic conductive materials include, for example, fillers, extenders, softeners, plasticizers, polymerization catalysts, curing catalysts, colorants, antioxidants, thermal stabilizers. In addition, various additives such as a light stabilizer, an ultraviolet absorber, a lubricant, an antistatic agent or 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. Examples of a method for dispersing conductive particles with insulating particles in the binder resin include, for example, a method in which conductive particles with insulating particles are added to a binder resin and then kneaded and dispersed with a planetary mixer or the like. After uniformly dispersing the particles in water or an organic solvent using a homogenizer or the like, then adding to the binder resin and kneading and dispersing with a planetary mixer or the like, or the binder resin with water or an organic solvent, etc. Examples include a method of adding conductive particles with insulating particles after dilution, and kneading and dispersing with a planetary mixer or the like.

  The anisotropic conductive material of the present invention can be used as an anisotropic conductive paste, anisotropic conductive ink, anisotropic conductive adhesive, anisotropic conductive film, or 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 or an anisotropic conductive sheet, the conductive particles with insulating particles are included. A film adhesive that does not include conductive particles with insulating particles may be laminated on the film adhesive.

  The content of the conductive particles with insulating particles is not particularly limited. From the viewpoint of improving the conduction reliability, the content of the conductive particles with insulating particles is preferably in the range of 0.01 to 20% by volume in 100% by volume of the anisotropic conductive material.

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

  The connection structure includes a first connection target member, a second connection target member, and a connection portion that electrically connects the first and second connection target members. The conductive particles of the invention or the anisotropic conductive material containing the conductive particles and a binder resin are preferably used. When the conductive particles 1 with insulating particles are used, the connecting portion itself is formed of the conductive particles 1 with insulating particles.

  Specific examples of the connection target member include electronic components such as a semiconductor chip, a capacitor, and a diode, and circuit boards such as a printed board, a flexible printed board, and a glass board.

  Examples of the electrode provided on the connection target member include a metal electrode such as a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a molybdenum electrode, or a tungsten electrode. When the connection target 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 object 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 metal oxide include indium oxide doped with a trivalent metal element, zinc oxide doped with a trivalent metal element, and the like. Examples of the trivalent metal element include Sn, Al, and Ga.

  In the case where the conductive particles with insulating particles of the present invention are used, the connection resistance value is lowered when the connection target member on which the metal electrode is formed is electrically connected. Among these, an aluminum electrode or a copper electrode is preferable.

  In FIG. 2, an example of the connection structure using the electroconductive particle which concerns on one Embodiment of this invention is typically shown with front sectional drawing.

  A connection structure 21 shown in FIG. 2 has a structure in which a printed circuit board 24 is connected to the upper surface of a glass substrate 22 via an anisotropic conductive film 23 including a plurality of conductive particles 1 with insulating particles. A plurality of electrodes 22 a are provided on the upper surface of the glass substrate 22. A plurality of electrodes 24 a are provided on the lower surface of the printed circuit board 24. The electrode 22 a and the electrode 24 a are connected by one or a plurality of conductive particles 2. In the present embodiment, a two-layer flexible printed circuit board is used as the printed circuit board 24. However, a connection target member other than the two-layer flexible printed board may be used. In FIG. 2, the printed circuit board 24 is schematically shown.

  The connection between the electrodes 22a and 24a is usually performed by placing the conductive particles 1 with insulating particles on the electrode 22a of the glass substrate 22, and then placing the printed circuit board 24 on the glass substrate 22 and the electrodes 22a and 24a facing each other. In such a manner, it is performed by overlapping and pressurizing. The conductive particles 1 with insulating particles are compressed by pressurization. At this time, the insulating particles 3 between the conductive particles 2 and the electrodes 22a and 24a can be eliminated. For example, during the pressurization, the insulating particles 3 existing between the conductive particles 2 and the electrodes 22a and 24a are melted or deformed, and the surface 2a of the conductive particles 2 is partially Exposed. In addition, since a big force is given in the case of the said pressurization, some insulating particles 3 peel from the surface 2a of the electroconductive particle 2, and the surface 2a of the electroconductive particle 2 is partially exposed. Sometimes. The portions where the surface 2a of the conductive particle 2 is exposed come into contact with the electrodes 22a and 24a, whereby the electrodes 22a and 24a can be electrically connected via the conductive particle 2.

The pressure of the said pressurization is about 9.8-10 < ⁴ > -4.9 * 10 < ⁶ > Pa. You may heat in the case of the said pressurization. The temperature of the said heating is about 120-220 degreeC.

  Further, as shown in FIG. 2, the insulating particles 3 are melted or deformed, so that the layer 25 derived from the insulating particles 3 is formed around the contact portion between the conductive particles 2 and the electrodes 22a and 24a. Sometimes formed.

  By the way, as shown in FIG. 5, in the conventional conductive particles 101 with insulating particles, the compression recovery rate of the base particles 101b constituting the conductive particles 101a is relatively high. When the electrodes 102 and 103 are connected using the conventional conductive particles 101 with insulating particles, the compressed conductive particles 101a are formed around the conductive particles 101 with insulating particles and the electrodes 102 and 103. By recovering the shape, the gap A is likely to occur. Furthermore, indentations are less likely to be formed at the portions where the conductive particles 101a of the electrodes 102 and 103 are in contact. For this reason, the connection resistance value between the electrodes 102 and 103 may not be sufficiently lowered. Furthermore, since the contact area between the conductive particles and the electrode 102 or the electrode 103 is small, the insulating particles 101c may be sandwiched between the conductive particles and the electrode 102 or the electrode 103, and the connection resistance value may be increased.

  In contrast, as shown in FIG. 3 where the conductive particles and the electrodes are in contact with each other, when the conductive particles 1 with insulating particles according to the present embodiment are used, the portions where the conductive particles 2 of the electrodes are in contact with each other. In addition, the indentation 26 is easily formed. For this reason, the connection resistance value between the electrodes 22a and 24a can be made sufficiently low. Further, the gap A is difficult to occur.

  Furthermore, when the conductive particles 1 with insulating particles are used, the contact area between the conductive particles 2 and the electrodes 22a and 24a can be increased, and the conduction reliability can be increased. As shown in another example of the contact portion between the conductive particle and the electrode in FIG. 4, even if the insulating particle 3A remains slightly between the conductive particle 2 and the electrode 22a, the insulating particle 3A remains. It can be made to conduct in the contact part 22B of the electrode around the non-contact part 22A of the electrode. For this reason, the connection resistance value between electrodes can be made low.

  When the insulating particle 3 having the P—OH group or the Si—OH group on the surface 3 a is used, the P—OH group or the Si—OH group is the conductive layer 5 on the surface 2 a of the conductive particle 2. In addition, it is chemically bonded to the electrodes 22a and 24a made of metal. For this reason, the layer 25 derived from the insulating particles 3 is strongly chemically bonded to the electrodes 22a and 24a. Therefore, since the layer 25 derived from the insulating particles 3 is firmly chemically bonded to the electrodes 22a and 24a, the adhesive strength between the conductive particles 2 and the electrodes 22a and 24a can be increased. For this reason, the connection reliability between electrodes can be improved.

  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.

  The following materials were prepared as monomer components for obtaining polymer particles.

(Monomer which is an alicyclic compound having at least two ring structures)
Dimethylol-tricyclodecane diacrylate 1,3-adamantanediol diacrylate isobornyl acrylate isobornyl methacrylate dicyclopentenyl acrylate dicyclopentanyl acrylate tricyclodecane vinyl ether tricyclodecane monomethyl vinyl ether

(Other monomers other than the monomer that is an alicyclic compound having at least two ring structures)
Divinylbenzene (manufactured by Nippon Steel Chemical Co., Ltd., “DVB960”)
Styrene Polytetramethylene glycol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., “Light acrylate PTMGA-250”)
Cyclohexyl acrylate Triethylene glycol diacrylate Trimethylolpropane triacrylate Pentaerythritol tetraacrylate

Example 1
(Production of polymer)
In a separable flask, 2500 g of ion-exchanged water, 250 g of styrene, 50 g of octyl mercaptan, and 0.5 g of sodium chloride were added and stirred under a nitrogen atmosphere. Then, it heated at 70 degreeC, 2.5 g of potassium peroxide was added, and polymer seed particle | grains were obtained by performing reaction for 24 hours.

  5 g of the obtained polymer seed particles, 500 g of ion-exchanged water, and 100 g of a 5% by weight aqueous solution of polyvinyl alcohol are mixed and dispersed by ultrasonic waves, then placed in a separable flask and stirred to disperse the polymer seed particles. A liquid was obtained.

  Dimethylol-tricyclodecane diacrylate 38 g, divinylbenzene 152 g, benzoyl peroxide 2.6 g, lauryl sulfate triethanolamine 10 g, and ethanol 130 g were added to ion-exchanged water 1000 g and stirred to obtain an emulsion. . The resulting emulsion was added to the polymer seed particle dispersion several times and stirred for 12 hours. Thereafter, 500 g of a 5% by weight aqueous solution of polyvinyl alcohol was added and reacted for 9 hours in a nitrogen atmosphere at 85 ° C. to obtain polymer particles.

(Preparation of conductive particles)
After the obtained polymer particles are washed and dried, a metal having a two-layer structure having a nickel layer on the surface of the polymer particles and a gold layer laminated on the surface of the nickel layer by an electroless plating method A layer was formed to produce conductive particles. The thickness of the nickel layer was 0.07 μm, and the thickness of the gold layer was 0.02 μm.

(Preparation of insulating particles)
A 1000 mL separable flask equipped with a four-neck separable cover, a stirring blade, a three-way cock, a condenser tube and a temperature probe, glycidyl methacrylate 45 mmol, methyl methacrylate 380 mmol, dimethacrylate ethylene glycol 13 mmol, acid phosphooxypolyoxyethylene A monomer composition containing 0.5 mmol of glycol methacrylate and 1 mmol of 2,2′-azobis {2- [N- (2-carboxyethyl) amidino] propane} was prepared. The monomer composition was weighed in distilled water so that the solid content was 10% by weight, stirred at 200 rpm, and polymerized at 60 ° C. for 24 hours in a nitrogen atmosphere. After completion of the reaction, the mixture was freeze-dried to obtain insulating particles A having the above-mentioned P—OH group derived from acid phosphooxypolyoxyethylene glycol methacrylate on the surface.

(Preparation of conductive particles with insulating particles)
Insulating particles A were adhered to the surfaces of the conductive particles as follows.

  The obtained insulating particles A were dispersed in distilled water under ultrasonic irradiation to obtain a 10 wt% aqueous dispersion of insulating particles A. 10 g of the obtained conductive particles A were dispersed in 500 mL of distilled water, 4 g of an aqueous dispersion of insulating particles A was added, and the mixture was stirred at room temperature for 6 hours to obtain conductive particles with insulating particles.

  The coverage of the conductive particles with insulating particles was measured by image analysis of SEM. A circle with a diameter half the diameter of the conductive particles with insulating particles is drawn on the SEM image, and the coverage of the conductive particles with insulating particles in the circle (per one conductive particle with insulating particles in the circle) Projected area × number of conductive particles with insulating particles / projected area of conductive particles with insulating particles in a circle). The coverage of the conductive particles by the insulating particles A was 52%.

(Preparation of anisotropic conductive film)
10 parts by weight of a bisphenol A type epoxy resin (“Epicoat 1009” manufactured by Japan Epoxy Resin Co., Ltd.), 40 parts by weight of acrylic rubber (weight average molecular weight of about 800,000), 200 parts by weight of methyl ethyl ketone, and a microcapsule type curing agent (Asahi Kasei Chemicals) 50 parts by weight of “HX3941HP” manufactured by the company and 2 parts by weight of silane coupling agent (“SH6040” manufactured by Toray Dow Corning Silicone) are mixed so that the content of the conductive particles with insulating particles becomes 3% by volume. And dispersed to obtain a resin composition.

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

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

(Examples 2 to 16 and Comparative Examples 1 to 4)
The polymer particles and conductive particles were the same as in Example 1 except that the types of monomer components used in the production of the polymer particles and the blending amounts thereof were changed as shown in Tables 1 and 2 below. Then, conductive particles with insulating particles, anisotropic conductive film, and connection structure were produced.

(Example 17)
The following electroless nickel plating process was performed using the polymer particles obtained in Example 1.

Electroless nickel plating process:
The resulting polymer particles were treated with a 10 wt% solution of ion adsorbent for 5 minutes and then added to a 0.01 wt% palladium sulfate aqueous solution. Thereafter, dimethylamine borane was added for reduction treatment, filtration, and washing to obtain polymer particles with palladium attached.

  Next, a 1% by weight sodium succinate solution in which sodium succinate was dissolved in 500 mL of ion exchange water was prepared. To this solution, 10 g of polymer particles with palladium attached were added and mixed to prepare a slurry. Sulfuric acid was added to the slurry, and the pH of the slurry was adjusted to 5.

  As a nickel plating solution, a nickel plating solution containing 10% by weight of nickel sulfate, 10% by weight of sodium hypophosphite, 4% by weight of sodium hydroxide and 20% by weight of sodium succinate was prepared. The slurry adjusted to pH 5 was heated to 80 ° C., and then the nickel plating solution was continuously added dropwise to the slurry and stirred for 20 minutes to advance the plating reaction. After confirming that hydrogen was no longer generated, the plating reaction was completed.

  Next, a late nickel plating solution containing 20% by weight of nickel sulfate, 5% by weight of dimethylamine borane and 5% by weight of sodium hydroxide was prepared. The late nickel plating solution was continuously added dropwise to the solution that had undergone the plating reaction with the previous nickel plating solution, and the plating reaction was allowed to proceed by stirring for 1 hour. In this way, a nickel layer was formed on the surface of the polymer particles to obtain conductive particles. The nickel layer had a thickness of 0.1 μm.

  Except having used the obtained electroconductive particle, it carried out similarly to Example 1, and produced the electroconductive particle with an insulating particle, an anisotropic conductive film, and the connection structure.

(Example 18)
The following electroless palladium plating process was performed using the conductive particles obtained in Example 17 except that the thickness of the nickel layer was adjusted to 0.07 μm.

Electroless palladium plating process:
10 g of the obtained conductive particles were added to 500 mL of ion-exchanged water and sufficiently dispersed by an ultrasonic treatment machine to obtain a particle suspension. While stirring the suspension at 50 ° C., 0.02 mol / L of palladium sulfate, 0.04 mol / L of ethylenediamine as a complexing agent, 0.06 mol / L of sodium formate as a reducing agent, and pH 10.0 containing a crystal modifier. The electroless plating solution was gradually added to perform electroless palladium plating. When the thickness of the palladium layer reached 0.03 μm, the electroless palladium plating was finished. Next, by washing and vacuum drying, conductive particles having a palladium layer laminated on the surface of the nickel layer were obtained.

  Except having used the obtained electroconductive particle, it carried out similarly to Example 1, and produced the electroconductive particle with an insulating particle, an anisotropic conductive film, and the connection structure. The nickel layer had a thickness of 0.07 μm, and the palladium layer had a thickness of 0.03 μm.

(Example 19)
An electroless nickel plating process was performed in the same manner as in Example 17 except that the polymer particles obtained in Example 1 were changed to the polymer particles obtained in Example 5, and nickel was formed on the surface of the polymer particles. A layer was formed to obtain conductive particles.

  Except having used the obtained electroconductive particle, it carried out similarly to Example 1, and produced the electroconductive particle with an insulating particle, an anisotropic conductive film, and the connection structure.

(Example 20)
The nickel layer was prepared to have a thickness of 0.07 μm, and the conductive particles obtained in Example 17 were changed to the conductive particles obtained in Example 19 in the same manner as in Example 18, An electroless palladium plating step was performed to obtain conductive particles having a palladium layer laminated on the surface of the nickel layer.

  Except having used the obtained electroconductive particle, it carried out similarly to Example 1, and produced the electroconductive particle with an insulating particle, an anisotropic conductive film, and the connection structure.

(Examples 21 to 46 and Comparative Examples 5 to 8)
In the same manner as in Example 1 except that the types of monomer components used in the production of the polymer particles and the blending amounts thereof were changed as shown in Tables 3 and 4 below, a polymer seed particle dispersion, Polymer particles, conductive particles, conductive particles with insulating particles, anisotropic conductive film, and connection structure were prepared.

(Example 47)
In a dispersion obtained by uniformly dispersing 1252 g of ion-exchanged water and 2135 g of a 5.5% by weight aqueous solution of polyvinyl alcohol, 38 g of dimethylol-tricyclodecane diacrylate, 152 g of divinylbenzene, and perbutyl O ( 5.9 g (manufactured by Nippon Oil & Fats Co., Ltd.) was added and mixed to obtain a mixed solution.

  The obtained mixture was polymerized at 70 ° C. for 5 hours under a nitrogen atmosphere, and then the particles were taken out by suction filtration. The particles were washed with ion-exchanged water and acetone to remove the dispersion medium and then dried to obtain polymer particles.

  The obtained polymer particles had an average particle size of 240 μm and a CV value of 0.42%. The polymer particles were electroless nickel plated to form a base nickel plating layer having a thickness of 0.3 μm on the surface of the polymer particles. Next, the polymer particles on which the base nickel plating layer was formed were subjected to electrolytic copper plating to form a copper layer having a thickness of 10 μm. Furthermore, electroplating was performed using an electrolytic plating solution containing tin and silver to form a low melting point metal layer having a thickness of 25 μm. In this way, conductive particles were produced in which a copper layer and a low melting point metal layer (tin: silver = 96.5 wt%: 3.5 wt%) were sequentially formed on the surface of the polymer particles. The average particle diameter of the conductive particles was 310 μm, and the CV value was 1.05%. The contents of tin and silver in the metal layer on the surface of the polymer particles were determined by analysis using a fluorescent X-ray analyzer (“EDX-800HS” manufactured by Shimadzu Corporation).

  Except having used the obtained electroconductive particle, it carried out similarly to Example 1, and produced the electroconductive particle with an insulating particle, an anisotropic conductive film, and the connection structure.

(Examples 48 to 50 and Comparative Example 9)
The polymer particles, conductive particles, insulation were the same as in Example 47 except that the types of monomer components used in the preparation of the polymer particles and the blending amounts thereof were changed as shown in Table 5 below. Conductive particles with particles, anisotropic conductive film, and connection structure were produced.

(Examples 51 to 90)
Polymer particles were obtained in the same manner as in Example 1 except that the types of monomer components used in the production of the polymer particles and the blending amounts thereof were changed as shown in Tables 6 to 8 below.

  Using the obtained polymer particles, an electroless nickel plating step was performed in the same manner as in Example 17 to form a nickel layer on the surface of the polymer particles, thereby obtaining conductive particles.

  Except having used the obtained electroconductive particle, it carried out similarly to Example 1, and produced the electroconductive particle with an insulating particle, an anisotropic conductive film, and the connection structure.

(Examples 91-130)
Polymer particles were obtained in the same manner as in Example 1 except that the types of monomer components used in the production of the polymer particles and the blending amounts thereof were changed as shown in Tables 8 to 10 below.

  The electroless nickel plating step and the electroless palladium plating step were performed in the same manner as in Examples 17 and 18 except that the obtained polymer particles were used so that the nickel layer had a thickness of 0.07 μm. Conductive particles were obtained in which a palladium layer was laminated on the surface of the nickel layer.

  Except having used the obtained electroconductive particle, it carried out similarly to Example 1, and produced the electroconductive particle with an insulating particle, an anisotropic conductive film, and the connection structure.

(Example 131)
Insulating particle B having the above P-OH group derived from acid phosphooxyethyl methacrylate on the surface in the same manner as insulating particle A, except that the acid phosphooxypolyoxyethylene glycol methacrylate was changed to acid phosphooxyethyl methacrylate. Got.

  Except having used the obtained insulating particle B, it carried out similarly to Example 1, and produced the electroconductive particle with an insulating particle, an anisotropic conductive film, and a connection structure.

(Example 132)
The P-OH derived from the acid phosphooxypolyoxypropylene glycol monomethacrylate in the same manner as the insulating particles A except that the acid phosphooxypolyoxyethylene glycol methacrylate was changed to acid phosphooxypolyoxypropylene glycol monomethacrylate. Insulating particles C having groups on the surface were obtained.

  Except having used the obtained insulating particle C, it carried out similarly to Example 1, and produced the electroconductive particle with an insulating particle, an anisotropic conductive film, and a connection structure.

(Example 133)
A 1000 mL separable flask equipped with a four-neck separable cover, a stirring blade, a three-way cock, a condenser tube, and a temperature probe was mixed with 45 mmol of glycidyl methacrylate, 380 mmol of methyl methacrylate, 13 mmol of ethylene glycol dimethacrylate, vinyltrihydroxysilane. A monomer composition containing 5 mmol and 1 mmol of 2,2′-azobis {2- [N- (2-carboxyethyl) amidino] propane} was prepared. The monomer composition was weighed in distilled water so that the solid content was 10% by weight, stirred at 200 rpm, and polymerized at 60 ° C. for 24 hours in a nitrogen atmosphere. After completion of the reaction, freeze-drying was performed to obtain insulating particles D having the Si—OH group derived from vinyltrihydroxysilane on the surface.

  Except having used the obtained insulating particle D, it carried out similarly to Example 1, and produced the electroconductive particle with an insulating particle, an anisotropic conductive film, and the connection structure.

(Example 134)
Insulation having the Si-OH group derived from 3-methacryloxypropyltrihydroxysilane on the surface in the same manner as the insulating particles D except that the vinyltrihydroxysilane was changed to 3-methacryloxypropyltrihydroxysilane. Particle E was obtained.

  Except having used the obtained insulating particle E, it carried out similarly to Example 1, and produced the electroconductive particle with an insulating particle, an anisotropic conductive film, and the connection structure.

(Evaluation)
(1) Average particle diameter of polymer particles The average particle diameter of the obtained polymer particles was measured using a Coulter counter (manufactured by Beckman Coulter).

(2) CV value of polymer particles The CV value of the obtained polymer particles was measured using a Coulter counter (manufactured by Beckman Coulter).

(3) Compression elastic modulus of polymer particles The compression elastic modulus (10% K value, 20% K value and 30% K value) of the obtained polymer particles was measured using a micro compression tester (Fischer Scope H manufactured by Fischer). -100 ").

(4) Compression recovery rate of polymer particles and conductive particles The compression recovery rate of the obtained polymer particles and conductive particles was measured using a micro compression tester (“Fischer Scope H-100” manufactured by Fischer). did.

(5) Connection resistance value The connection resistance value between the opposing electrodes of the obtained connection structure was measured by a four-terminal method. The connection resistance value was evaluated according to the following evaluation criteria.

[Evaluation criteria for connection resistance]
◎: Connection resistance value is 2.0Ω or less ○: Connection resistance value exceeds 2.0Ω, 3.0Ω or less Δ: Connection resistance value exceeds 3.0Ω, 5.0Ω or less ×: Connection resistance value is 5. Over 0Ω

(6) Observation of electrodes Using a differential interference microscope, the electrodes provided on the glass substrate were observed from the glass substrate side of the obtained connection structure, and the presence or absence of formation of indentations on the electrodes in contact with the conductive particles was determined as follows. It was evaluated according to the evaluation criteria. Moreover, the presence or absence of the space | gap generation | occurrence | production in the electrode part which the electroconductive particle contacted was observed using the metal microscope. In addition, the presence or absence of the formation of the impression of the electrode was observed with a differential interference microscope so that the electrode area was 0.02 mm ^2, and the number of impressions per electrode of 0.02 mm ² was calculated. Arbitrary ten places were observed with the differential interference microscope, and the average value of the number of impressions per electrode 0.02 mm ² was calculated.

[Evaluation criteria for the presence or absence of indentation]
◎: 25 or more impressions per electrode 0.02 mm ² ○: 20 or more impressions per electrode 0.02 mm ² , less than 25 △: 5 or more impressions per electrode 0.02 mm ² , less than 20 X: Less than 5 impressions per electrode 0.02 mm ²

(7) Drop strength test A silicon chip (length 6 mm × width 6 mm) provided with 112 electrodes (diameter 280 μm) at intervals of 0.5 mm was prepared. A flux (“WS-9160-M7” manufactured by Cookson Electronics Co., Ltd.) was applied on the electrode of this silicon chip. The obtained electroconductive particle was arrange | positioned to all the electrodes, reflow was performed on the conditions of the heating temperature of 250 degreeC, and 30 second, and the electroconductive particle was mounted on the electrode.

  Next, a printed circuit board provided with a copper electrode (diameter 305 μm) was prepared. A solder paste (“M705-GRN360-K2-V” manufactured by Senju Metal Industry Co., Ltd.) was applied to the printed circuit board. Fifteen silicon chips with conductive particles mounted on electrodes were mounted on a printed circuit board coated with solder paste to obtain a connection structure.

  According to JEDEC standard JESD22-B111, the obtained connection structure was subjected to a drop strength test and evaluated according to the following evaluation criteria.

  Since the obtained connection structure has a daisy chain circuit, the disconnection can be detected if the electrode is disconnected even at one location. The electrode is an electrode in which a copper layer, a nickel-phosphorus layer, and a gold layer are sequentially formed toward the outer surface.

[Evaluation criteria for drop impact test]
○: In all 15 silicon chips, the number of drops in which the electrodes are disconnected is 100 times or more. Δ: In all 15 silicon chips, the number of drops in which the electrodes are disconnected is 50 times or more and less than 100 times. In all 15 silicon chips, the number of times the electrode is disconnected is less than 50 times

  The results are shown in Tables 1 to 11 below. In addition, in the following Tables 1-11, a monomer component shows the monomer component used in the case of preparation of a polymer particle. Further, “-” indicates that evaluation is not performed.

  Tables 1 to 4 and 6 to 11 showing the evaluation results of Examples 1 to 46 and 51 to 134 show that good results can be obtained when a two-layer flexible printed board is used. Even if a three-layer flexible printed circuit board is used instead of the two-layer flexible printed circuit board, the use of the polymer particles, conductive particles, and conductive particles with insulating particles in Examples 1 to 46 and 51 to 134 gives good results. It was confirmed that it was obtained. Moreover, it can be understood from Table 5 showing the evaluation results of Examples 47 to 50 that the disconnection of the electrode can be suppressed even when a drop impact is applied.

  In Tables 1 to 4 and 6 to 11 showing the evaluation results of Examples 1 to 46 and 51 to 134, it is shown that good results are obtained in the case of an aluminum electrode. Even if the aluminum electrode provided on the glass substrate is replaced with a copper electrode, good results are obtained by using the polymer particles, conductive particles, and conductive particles with insulating particles of Examples 1 to 46 and 51 to 134. It was confirmed.

  In Examples 1 to 134, the electrodes were electrically connected via the conductive particles of the conductive particles with insulating particles, and the connection resistance value was low.

DESCRIPTION OF SYMBOLS 1 ... Conductive particle with insulating particle 2 ... Conductive particle 2a ... Surface 3 ... Insulating particle 3a ... Surface 4 ... Polymer particle 4a ... Surface 5 ... Conductive layer 21 ... Connection structure 22 ... Glass substrate 22a ... Electrode 22A ... Non Contact part 22B ... Contact part 23 ... Anisotropic conductive film 24 ... Printed circuit board 24a ... Electrode 25 ... Layer derived from insulating particles 26 ... Indentation

Claims (10)

Polymer particles, and conductive particles having a conductive layer covering the surface of the polymer particles;
Insulating particles adhering to the surface of the conductive particles,
Conductive particles with insulating particles, wherein the polymer particles are polymer particles obtained by polymerizing a monomer that is an alicyclic compound having at least two ring structures.   The conductive particles with insulating particles according to claim 1, wherein the at least two ring structures are a bicyclo ring structure or a tricyclo ring structure.   The conductive particles with insulating particles according to claim 1, wherein the monomer is an acrylic monomer.   The polymer particles are polymer particles obtained by polymerizing a monofunctional monomer that is an alicyclic compound having at least two ring structures and a polyfunctional monomer. 2. Conductive particles with insulating particles according to item 1.   The insulation according to any one of claims 1 to 3, wherein the polymer particles are polymer particles obtained by polymerizing a polyfunctional monomer that is an alicyclic compound having at least two ring structures. Conductive particles with particles.   The polymer particles are obtained by polymerizing a monofunctional monomer that is an alicyclic compound having at least two ring structures and a polyfunctional monomer that is an alicyclic compound having at least two ring structures. The electroconductive particle with an insulating particle according to any one of claims 1 to 3, which is a coalesced particle.   The conductive particles with insulating particles according to claim 1, wherein an outer surface of the conductive layer is a conductive layer containing nickel, a conductive layer containing palladium, or a conductive layer containing a low melting point metal.   The conductive particles with insulating particles according to claim 1, wherein the insulating particles have a hydroxyl group directly bonded to a phosphorus atom or a hydroxyl group directly bonded to a silicon atom on the surface.   An anisotropic conductive material comprising the conductive particles with insulating particles according to claim 1 and a binder resin. A first connection target member, a second connection target member, and a connection portion connecting the first and second connection target members;
The connection is formed of an anisotropic conductive material including the conductive particles with insulating particles according to any one of claims 1 to 9, or the conductive particles with insulating particles and a binder resin. Structure.

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