JP6533427B2 - Conductive material and connection structure - Google Patents

Description

  The present invention relates to a conductive material comprising conductive particles having a solder. The present invention also relates to a connection structure using the above-mentioned conductive material.

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

  The anisotropic conductive material is, for example, a connection between a flexible printed substrate and a glass substrate (FOG (Film on Glass)) and a connection between a semiconductor chip and a flexible printed substrate (COF (COF) to obtain various connection structures. It is used for chip on film), connection between semiconductor chip and glass substrate (COG (chip on glass)), connection between flexible printed circuit board and glass epoxy substrate (FOB (film on board)), and the like.

  For example, when electrically connecting an electrode of a flexible printed board and an electrode of a glass epoxy board with the above-mentioned anisotropic conductive material, an anisotropic conductive material containing conductive particles is arranged on the glass epoxy board Do. Next, the flexible printed circuit is laminated, and heated and pressurized. Thus, the anisotropic conductive material is cured to electrically connect the electrodes via the conductive particles to obtain a connection structure.

  As an example of the anisotropic conductive material, Patent Document 1 below describes an anisotropic conductive material containing conductive particles and a resin component whose curing is not completed at the melting point of the conductive particles. Specifically as the conductive particles, tin (Sn), indium (In), bismuth (Bi), silver (Ag), copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd) And metals such as gallium (Ga), silver (Ag) and thallium (Tl), and alloys made of these metals.

  In Patent Document 1, a resin heating step of heating the anisotropic conductive resin to a temperature which is higher than the melting point of the conductive particles and the curing of the resin component is not completed, and a resin component curing step of curing the resin component. And electrically connecting between the electrodes is described. Further, Patent Document 1 describes that mounting is performed with the temperature profile shown in FIG. 8 of Patent Document 1. In Patent Document 1, the conductive particles are melted in the resin component whose curing is not completed at the temperature at which the anisotropic conductive resin is heated.

  Patent Document 2 below discloses an adhesive tape comprising a resin layer containing a thermosetting resin, a solder powder, and a curing agent, wherein the solder powder and the curing agent are present in the resin layer. There is. The adhesive tape is in the form of a film, not in the form of paste.

  Further, Patent Document 2 discloses a bonding method using the above-mentioned adhesive tape. Specifically, a first substrate, an adhesive tape, a second substrate, an adhesive tape, and a third substrate are laminated in this order from the bottom to obtain a laminate. At this time, the first electrode provided on the surface of the first substrate and the second electrode provided on the surface of the second substrate are opposed to each other. Further, the second electrode provided on the surface of the second substrate and the third electrode provided on the surface of the third substrate are opposed to each other. Then, the laminate is heated at a predetermined temperature and adhered. Thereby, a connection structure is obtained.

  Further, in Patent Document 3 below, a semiconductor chip having a plurality of connection terminals is disposed to face a wiring substrate having a plurality of electrode terminals, and the above-mentioned electrode terminals of the wiring substrate and the above-mentioned semiconductor chip A flip chip mounting method of electrically connecting with a connection terminal is disclosed. This flip chip mounting method comprises the steps of (1) supplying a resin containing solder powder and a convection additive onto the surface of the wiring substrate having the electrode terminal, and (2) the semiconductor chip on the resin surface. And (3) heating the wiring substrate to a temperature at which the solder powder melts, and (4) curing the resin after the heating step. In the heating step (3) of the wiring substrate, a connection body for electrically connecting the electrode terminal and the connection terminal is formed, and in the curing step (4) of the resin, the semiconductor chip is used as the wiring substrate Fix to

JP, 2004-260131, A WO2008 / 023452A1 Unexamined-Japanese-Patent No. 2006-114865

  In the case of a conventional solder powder or an anisotropic conductive paste containing conductive particles having a solder layer on the surface, the solder powder or the conductive particles may not be efficiently disposed on the electrode (line). In conventional solder powder or conductive particles, the moving speed of the solder powder or conductive particles onto the electrode may be slow.

  Moreover, when electrically connecting between electrodes by the method of patent document 1 using the anisotropic conductive material of patent document 1, the electroconductive particle containing a solder will be efficiently on an electrode (line). May not be placed. Further, in the embodiment of Patent Document 1, in order to move the solder sufficiently at a temperature equal to or higher than the melting point of the solder, the temperature is maintained at a constant temperature, and the manufacturing efficiency of the connection structure is lowered. If mounting is performed with the temperature profile shown in FIG. 8 of Patent Document 1, the manufacturing efficiency of the connection structure is lowered.

  In patent document 2, about the electroconductive particle used for anisotropic conductive material, there is no specific description. In the Example of patent document 3, the copper layer is formed on the surface of a resin particle, and the electroconductive particle by which the solder layer is formed in the surface of this copper layer is used. The central portion of the conductive particles is composed of resin particles. In addition, when the anisotropic conductive materials described in Patent Documents 2 and 3 are used, conductive particles are difficult to be efficiently disposed on the electrodes (lines), and positional deviation between the upper and lower electrodes to be connected occurs. There is something to do.

  Further, in conventional anisotropic conductive materials, when used after storage, the conductive particles may be more difficult to be disposed on the electrodes (lines).

  An object of the present invention is to enable solder in conductive particles to be efficiently disposed on electrodes, before and after storage of the conductive material, and to improve the reliability of conduction between the electrodes. It is to provide a conductive material capable of Another object of the present invention is to provide a connection structure using the above-mentioned conductive material.

  According to a broad aspect of the present invention, the conductive particle includes a plurality of conductive particles and a binder, the conductive particle includes a solder on the outer surface portion of the conductive portion, and the conductive particle is the conductive portion of the conductive portion. The imidazole ring and the group represented by the following formula (1) are provided on the outer surface of the solder, and the imidazole ring is located between the outer surface of the solder and the group represented by the formula (1) A conductive material is provided, in which is located.

  In said Formula (1), R1, R2 and R3 respectively represent an alkyl group, a hydroxyl group, an alkoxy group, or a carboxyl group containing group.

  In one particular aspect of the conductive material according to the present invention, the conductive particles are surface-treated with an imidazole silane coupling agent.

  In a specific aspect of the conductive material according to the present invention, the conductive particles have an imidazole ring and an ether chain or a linear portion having 4 to 12 carbon atoms on the outer surface of the solder of the conductive portion. The ether chain or the carbon chain is located between a carbon chain and a group represented by the formula (1), and the imidazole ring and the group represented by the formula (1) .

  In a particular aspect of the conductive material according to the present invention, in the formula (1), at least one of R1, R2 and R3 represents a carboxyl group-containing group.

  In one specific aspect of the conductive material according to the present invention, the conductive particles are solder particles formed by solder.

  In one particular aspect of the conductive material according to the present invention, the binder comprises a thermosetting compound and a thermosetting agent.

  In a specific aspect of the conductive material according to the present invention, the average particle diameter of the conductive particles is 1 μm or more and 60 μm or less.

  In a specific aspect of the conductive material according to the present invention, the content of the conductive particles is 10% by weight or more and 80% by weight or less in 100% by weight of the conductive material.

  According to a broad aspect of the present invention, a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, the first connection target member, and the first connection target member And a connection portion connecting the second connection target member, the connection portion is formed of the above-described conductive material, and the first electrode and the second electrode are the conductive particles. A connection structure is provided, which is electrically connected by the solder at.

  The conductive material according to the present invention includes a plurality of conductive particles and a binder, and the conductive particles have a solder on the outer surface portion of the conductive portion, and the conductive particles are the above-mentioned conductive portions. The outer surface of the solder has an imidazole ring and a group represented by the above formula (1), and the above imidazole ring is present between the outer surface of the above solder and the group represented by the above formula (1) Being located, the solder in the conductive particles can be efficiently placed on the electrodes, either before or after storage of the conductive material, and the conduction reliability between the electrodes can be improved. Can.

FIG. 1 is a cross-sectional view schematically showing a connection structure obtained by using a conductive material according to an embodiment of the present invention. FIGS. 2 (a) to 2 (c) are cross-sectional views for explaining each step of an example of a method of manufacturing a connection structure using a conductive material according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing a modified example of the connection structure. FIG. 4 is a cross-sectional view showing a first example of conductive particles that can be used for the conductive material. FIG. 5 is a cross-sectional view showing a second example of conductive particles usable for the conductive material. FIG. 6 is a cross-sectional view showing a third example of conductive particles usable for the conductive material.

  Hereinafter, the present invention will be described in detail.

(Conductive material)
The conductive material according to the present invention includes a plurality of conductive particles and a binder. The conductive particles have a conductive portion. The conductive particles have solder on the outer surface portion of the conductive portion. The solder is contained in the conductive portion and is a part or all of the conductive portion.

  In the conductive material according to the present invention, the conductive particle has an imidazole ring and a group represented by the formula (1) described later on the outer surface of the solder of the conductive portion. The imidazole ring is located between the outer surface of the solder and the group represented by the formula (1).

  In the present invention, since the conductive material contains specific conductive particles, the corrosion of the solder can be considerably suppressed. In the present invention, since the above configuration is provided, when the electrodes are electrically connected, the solder in the conductive particle is easily collected between the upper and lower facing electrodes, and the solder in the conductive particle is Line) can be placed efficiently. In addition, a part of the solder in the conductive particles is difficult to be disposed in the area (space) where the electrode is not formed, and the amount of the solder disposed in the area where the electrode is not formed can be considerably reduced. In the present invention, conductive particles not located between opposed electrodes can be efficiently moved between the opposed electrodes. Therefore, the conduction reliability between the electrodes can be enhanced. Moreover, electrical connection between laterally adjacent electrodes, which should not be connected, can be prevented, and insulation reliability can be enhanced.

  Furthermore, in the present invention, the corrosion of the solder in the conductive particles is difficult to progress, and the storage stability of the conductive material is excellent. Therefore, regardless of whether the conductive material is stored or after storage, the solder in the conductive particles can be efficiently disposed on the electrodes, and the conduction reliability between the electrodes can be enhanced.

  Furthermore, in the present invention, positional deviation between the electrodes can be prevented. In the present invention, when the second connection target member is superimposed on the first connection target member having the conductive material disposed on the upper surface, the electrode of the first connection target member and the electrode of the second connection target member Even when the first connection target member and the second connection target member are overlapped with each other in a state in which the alignment of the first connection target member and the second connection target member are corrected, the shift is corrected and the electrode of the first connection target member and the second connection target The electrode of the member can be connected (self alignment effect).

  The conductive particles may be solder particles formed of solder. The solder particles have solder on the outer surface portion of the conductive portion. In the solder particles, both the central portion and the outer surface portion of the conductive portion are formed of solder. The conductive particles may have base particles and conductive portions disposed on the surface of the base particles. In this case, the conductive particles have solder on the outer surface portion of the conductive portion.

In addition, compared with the case where the electroconductive particle provided with the said solder particle is used, the case where the electroconductive particle provided with the base material particle which is not formed by the solder and the solder part arrange | positioned on the surface of the substrate particle is used. The conductive particles are less likely to collect on the electrodes, and the solderability of the conductive particles is low, so the conductive particles moved onto the electrodes tend to move out of the electrodes, There is also a tendency for the effect of suppressing misalignment to be reduced. Therefore, it is preferable that the said electroconductive particle has the solder particle formed of the solder.

  The conductive material and the binder preferably include a thermoplastic component or a thermosetting component. The conductive material and the binder may contain a thermoplastic component, and may contain a thermosetting component. The conductive material and the binder preferably contain a thermosetting component. The conductive material and the binder preferably include a thermosetting compound and a thermosetting agent.

  The viscosity (η 25) at 25 ° C. of the conductive material is preferably 10 Pa · s or more, more preferably 50 Pa · s or more, still more preferably 100 Pa · s or more, in order to arrange the solder more efficiently on the electrode. Preferably it is 800 Pa.s or less, More preferably, it is 600 Pa.s or less, More preferably, it is 500 Pa.s or less.

  The viscosity (η 25) can be appropriately adjusted to the type and the amount of the blending component. Also, the use of a filler can make the viscosity relatively high.

  The viscosity (η 25) can be measured, for example, using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.) or the like under the conditions of 25 ° C. and 5 rpm.

  The said conductive material can be used as a conductive paste, a conductive film, etc. The conductive film is preferably an anisotropic conductive film. From the viewpoint of arranging the solder more efficiently on the electrodes, the conductive material is preferably an anisotropic conductive paste. The said conductive material is used suitably for the electrical connection of an electrode. The conductive material is preferably a circuit connection material.

  Hereinafter, each component contained in the said electrically-conductive material is demonstrated.

(Conductive particles)
The conductive particles electrically connect the electrodes of the connection target member. The conductive particles have solder on the outer surface portion of the conductive portion. In the conductive particles, specific functional groups are present on the outer surface of the solder.

  The said electroconductive particle has an imidazole ring and group represented by following formula (1) on the outer surface of the said solder of the said electroconductive part. The imidazole ring is located between the outer surface of the solder and the group represented by the formula (1).

  In the above formula (1), R1, R2 and R3 each represent an alkyl group, a hydroxyl group, an alkoxy group or a carboxyl group-containing group.

The carbon number of the above-mentioned alkyl group and alkoxy group is preferably 5 or less, more preferably 4 or less, still more preferably 3 or less, and still more preferably 2 or less.

  An imidazole ring is chemically bonded to the outer surface of the solder from the viewpoint of effectively suppressing the corrosion of the solder, arranging the solder more efficiently on the electrodes, and further suppressing the positional deviation between the electrodes. Is preferred.

  From the viewpoint of effectively suppressing the corrosion of the solder, arranging the solder more efficiently on the electrodes, and further suppressing the positional deviation between the electrodes, the conductive particle is the outer surface of the solder of the conductive portion. And an imidazole ring, a carbon chain having 4 to 12 carbon atoms in the ether chain or linear portion, and a group represented by the above formula (1), and the above imidazole ring and the above formula (1) Preferably, the ether chain or the carbon chain is located between the group represented by and the group represented by

  An alkyl group, an ether chain, or a hydroxyl group may be bonded as a side chain to the ether chain and the carbon chain having 4 to 12 carbon atoms in the linear portion. The carbon number of the side chain ether chain and the alkyl group is preferably 3 or less, more preferably 2 or less. It is preferable that an alkyl group and an ether chain are not bonded as a side chain to the ether chain and the carbon chain having 4 to 12 carbon atoms in the linear portion. The ether chain is preferably an ether chain having 2 to 6 carbon atoms. The carbon chain is preferably an alkylene group.

  From the viewpoint of effectively suppressing the corrosion of the solder, arranging the solder more efficiently on the electrodes, and further suppressing the positional deviation between the electrodes, it is possible to suppress the displacement between the electrodes. It is preferable that at least one represents a carboxyl group-containing group. In particular, the cohesion performance of the solder is considerably enhanced by the presence of carboxyl group-containing groups.

  From the viewpoint of effectively suppressing the corrosion of the solder, arranging the solder more efficiently on the electrodes, and further suppressing the positional deviation between the electrodes, the conductive particles have a surface using an imidazole silane coupling agent. Preferably it is obtained by treatment. The conductive particles are preferably surface-treated with an imidazole silane coupling agent. An imidazole silane coupling agent can be reacted with hydroxyl groups on the surface of the solder.

  The said anisotropic electrically-conductive material performs electroconductive particle which has an imidazole ring and group represented by the said Formula (1) on the outer surface of the solder of an electroconductive part by surface-treating using an imidazole silane coupling agent. After being obtained, it is preferable that the conductive particles and the binder be mixed.

  From the viewpoint of effectively suppressing the corrosion of the solder, arranging the solder more efficiently on the electrodes, and further suppressing the positional deviation between the electrodes, the conductive particles are surfaced using an imidazole silane coupling agent. It is preferable that it is obtained by introduce | transducing a carboxyl group-containing group after processing. The conductive particles preferably have a group derived from an imidazole silane coupling agent and a carboxyl-containing group, and the solder and the carboxyl group-containing group are bonded via a group derived from the imidazole silane coupling agent Is preferred. For example, a carboxyl group-containing group can be introduced to the alkoxy group of the alkoxysilyl group in the imidazole silane coupling agent.

  Examples of the imidazole silane coupling agent include IS-1000, IS-1000D, SP-1000, IA-100A, IA-100P, and IA-100F manufactured by Nippon Mining Materials Co., Ltd. The imidazole silane coupling agent may be used alone or in combination of two or more.

The imidazole silane coupling agent is preferably a reaction product of an imidazole compound and a silane coupling agent having an epoxy group. The imidazole compound includes imidazole, and imidazole having a substituent introduced at the 2- or 4-position. As a substituent, a methyl group, an ethyl group, a propyl group, a butyl group, a cyano group, a -CHO group, a phenyl group and a benzyl group can be mentioned. As the silane coupling agent having an epoxy group, a 3-glycidoxypropylsilane compound is preferable, and 3-glycidoxypropyldimethoxysilane, 3-glycidoxypropylmethyltrimethoxysilane, 3-glycidoxypropyl is particularly preferable. Methyldiethoxysilane or 3-glycidoxypropyltriethoxysilane is preferred.

  In particular, an imidazole silane coupling agent represented by the following formula (11) is preferable.

  In the above formula (11), R1, R2 and R3 each represent an alkyl group, a hydroxyl group, an alkoxy group or a carboxyl group-containing group, R4 and R5 each represent a methyl group, an ethyl group, a propyl group, a butyl group, a cyano group, -CHO group, a phenyl group or a benzyl group is represented, n represents the integer of 1-9.

  The carbon number of the above-mentioned alkyl group and alkoxy group in R1, R2 and R3 is preferably 5 or less, more preferably 4 or less, still more preferably 3 or less, particularly preferably 2 or less.

  As a method of obtaining the above reaction product, a method in which a silane coupling agent having an epoxy group is dropped and reacted with an imidazole compound melted by heat, and a silane having an epoxy group in an imidazole compound in a solvent such as acetone. The method of making a coupling agent react by refluxing etc. are mentioned. Recrystallization may be performed as needed.

  As compounds for introducing the above-mentioned carboxyl group-containing group, levulinic acid, glutaric acid, glycolic acid, succinic acid, malic acid, oxalic acid, malonic acid, adipic acid, 5-ketohexanoic acid, 3-hydroxypropionic acid, 4 -Aminobutyric acid, 3-mercaptopropionic acid, 3-mercaptoisobutyric acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid, 4-phenylbutyric acid, decanoic acid, dodecanoic acid, tetradecanoic acid, pentadecanoic acid Hexadecanoic acid, 9-hexadecenoic acid, heptadecanoic acid, stearic acid, oleic acid, acetic acid, linoleic acid, (9,12,15) -linolenic acid, nonadecanoic acid, arachidic acid, decanedioic acid and dodecanedioic acid, etc. And their esters and their anhydrides. Glutaric acid, adipic acid or glycolic acid is preferred. As the compound for introducing the carboxyl group-containing group, only one type may be used, or two or more types may be used in combination.

  As needed, after converting the alkoxyl group of a silane coupling agent into silanol with water etc., you may make the compound for introduce | transducing the said carboxyl group-containing group.

  As a specific method of obtaining the conductive particles having the above-mentioned functional group on the outer surface of the solder, a method of putting conductive particles in a solvent and adding an imidazole silane coupling agent while heating may be mentioned.

  Next, specific examples of the conductive particles will be described with reference to the drawings.

  FIG. 4 is a cross-sectional view showing a first example of conductive particles that can be used for the conductive material.

  The conductive particles 21 shown in FIG. 4 are solder particles. The conductive particles 21 are entirely formed of solder. The conductive particles 21 do not have base particles in the core and are not core-shell particles. In the conductive particles 21, both the central portion and the outer surface portion of the conductive portion are formed of solder.

  FIG. 5 is a cross-sectional view showing a second example of conductive particles usable for the conductive material.

  The conductive particle 31 shown in FIG. 5 includes a substrate particle 32 and a conductive portion 33 disposed on the surface of the substrate particle 32. The conductive portion 33 covers the surface of the base particle 32. The conductive particle 31 is a coated particle in which the surface of the base particle 32 is covered by the conductive portion 33.

  The conductive portion 33 has a second conductive portion 33A and a solder portion 33B (first conductive portion). The conductive particle 31 includes a second conductive portion 33A between the base particle 32 and the solder portion 33B. Therefore, the conductive particles 31 include the base particle 32, the second conductive portion 33A disposed on the surface of the base particle 32, and the solder portion 33B disposed on the outer surface of the second conductive portion 33A. And

  FIG. 6 is a cross-sectional view showing a third example of conductive particles usable for the conductive material.

  As described above, the conductive portion 33 in the conductive particle 31 has a two-layer structure. The conductive particle 41 shown in FIG. 6 has a solder portion 42 as a single layer conductive portion. The conductive particles 41 include base particles 32 and solder portions 42 disposed on the surfaces of the base particles 32.

  Examples of the substrate particles include resin particles, inorganic particles other than metal particles, organic-inorganic hybrid particles, metal particles and the like. The base particle is preferably a base particle excluding a metal, and is preferably a resin particle, an inorganic particle excluding a metal particle, or an organic-inorganic hybrid particle. The substrate particles may be copper particles.

  Various organic substances are suitably used as the resin for forming the above-mentioned resin particles. Examples of the resin for forming the above resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; polycarbonate , Polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide , Polyacetal, polyimide, polyamide imide, polyether ether Tons, polyether sulfone, divinyl benzene polymer, and divinylbenzene copolymer, and the like. Examples of the divinylbenzene copolymer and the like include divinylbenzene-styrene copolymer and divinylbenzene- (meth) acrylic acid ester copolymer and the like. Since the hardness of the resin particle can be easily controlled to a suitable range, the resin for forming the resin particle is a weight obtained by polymerizing one or two or more polymerizable monomers having an ethylenically unsaturated group. It is preferable to be combined.

When the resin particles are obtained by polymerizing a monomer having an ethylenically unsaturated group, as the monomer having an ethylenically unsaturated group, a monomer having a crosslinking property with a non-crosslinkable monomer is used. And a mer.

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

  Examples of the crosslinkable monomer include, for example, tetramethylolmethane tetra (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and dipentamer. Erythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) Multifunctional (meth) acrylates such as acrylate, (poly) tetramethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate; triallyl (iso) cyanurets And silane-containing monomers such as triallyl trimellitate, divinylbenzene, diallyl phthalate, diallyl acrylamide, diallyl ether, .gamma .- (meth) acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, vinyltrimethoxysilane, etc. Be

  The said resin particle can be obtained by polymerizing the polymerizable monomer which has the said ethylenically unsaturated group by a well-known method. Examples of this method include a method of suspension polymerization in the presence of a radical polymerization initiator, and a method of swelling and polymerizing a monomer with a radical polymerization initiator using non-crosslinked seed particles.

  When the substrate particles are inorganic particles or organic-inorganic hybrid particles other than metal, examples of the inorganic substance for forming the substrate particles include silica and carbon black. The particles formed of the above silica are not particularly limited. For example, after forming a crosslinked polymer particle by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups, baking is carried out as necessary. The particles obtained by carrying out are mentioned. As said organic-inorganic hybrid particle | grains, the organic-inorganic hybrid particle | grains etc. which were formed, for example by bridge | crosslinking alkoxy silyl polymer and acrylic resin are mentioned.

  When the base particle is a metal particle, examples of the metal for forming the metal particle include silver, copper, nickel, silicon, gold and titanium. When the base particle is a metal particle, the metal particle is preferably a copper particle. However, it is preferable that the said base material particle is not a metal particle.

The method of forming a conductive portion on the surface of the base particle and the method of forming a solder portion on the surface of the base particle or the surface of the second conductive portion are not particularly limited. As the method of forming the conductive portion and the solder portion, for example, a method by electroless plating, a method by electroplating, a method by physical collision, a method by mechanochemical reaction, a method by physical vapor deposition or physical adsorption, And a method of coating a metal powder or a paste containing a metal powder and a binder on the surface of a substrate particle, and the like. Among them, a method by electroless plating, electroplating or physical collision is preferable. Examples of the method by physical vapor deposition include methods such as vacuum deposition, ion plating and ion sputtering. Further, in the method based on the physical collision, for example, a theta composer (manufactured by Tokuju Craft Co., Ltd.) or the like is used.

  The melting point of the substrate particles is preferably higher than the melting point of the solder portion. The melting point of the substrate particles is preferably more than 160 ° C., more preferably more than 300 ° C., still more preferably more than 400 ° C., particularly preferably more than 450 ° C. The melting point of the base material particles may be less than 400 ° C. The melting point of the substrate particles may be 160 ° C. or less. The softening point of the substrate particles is preferably 260 ° C. or more. The softening point of the base particle may be less than 260 ° C.

  The conductive particles may have a single-layer solder portion. The conductive particles may have conductive portions (solder portions, second conductive portions) of a plurality of layers. That is, in the conductive particle, two or more conductive portions may be stacked.

  The solder is preferably a low melting point metal having a melting point of 450 ° C. or less. The solder portion is preferably a low melting point metal layer having a melting point of 450 ° C. or less. The low melting point metal layer is a layer containing a low melting point metal. The solder in the conductive particles is preferably a low melting point metal particle having a melting point of 450 ° C. or less. The low melting point metal particles are particles containing a low melting point metal. The low melting point metal means a metal having a melting point of 450 ° C. or less. The melting point of the low melting point metal is preferably 300 ° C. or less, more preferably 160 ° C. or less. Moreover, it is preferable that the solder in the said electroconductive particle contains a tin. The content of tin is preferably 30% by weight or more, more preferably 40% by weight or more, and still more preferably 100% by weight of the metal contained in the solder portion and 100% by weight of the metal contained in the solder of the conductive particles. It is at least 70% by weight, particularly preferably at least 90% by weight. When the content of tin in the solder in the conductive particles is at least the above lower limit, the conduction reliability between the conductive particles and the electrode is further enhanced.

  The content of tin is determined using a high-frequency inductively coupled plasma emission spectrometer ("ICP-AES" manufactured by Horiba, Ltd.) or a fluorescent X-ray analyzer ("EDX-800HS" manufactured by Shimadzu Corporation). It can be measured.

  By using the conductive particles having the above-described solder on the outer surface portion of the conductive portion, the solder is melted and joined to the electrodes, and the solder brings the electrodes into conduction. For example, since the solder and the electrode are likely to be in surface contact rather than point contact, connection resistance is lowered. In addition, the use of conductive particles having solder on the outer surface portion of the conductive part increases the bonding strength between the solder and the electrode. As a result, peeling between the solder and the electrode is more difficult to occur, and conduction reliability is effective. Become high.

  The low melting point metal which comprises the said solder part and the said solder particle is not specifically limited. The low melting point metal is preferably tin or an alloy containing tin. Examples of the alloy include tin-silver alloy, tin-copper alloy, tin-silver-copper alloy, tin-bismuth alloy, tin-zinc alloy, tin-indium alloy and the like. Among them, it is preferable that the low melting point metal is tin, a tin-silver alloy, a tin-silver-copper alloy, a tin-bismuth alloy, or a tin-indium alloy because the wettability to the electrode is excellent. More preferably, tin-bismuth alloy or tin-indium alloy is used.

  It is preferable that the material which comprises the said solder (solder part) is a filler material whose liquidus line is 450 degrees C or less based on JISZ3001: welding term. Examples of the composition of the solder include metal compositions containing zinc, gold, silver, lead, copper, tin, bismuth, indium and the like. Among these, a tin-indium-based (117 ° C. eutectic) that is low in melting point and lead free, or a tin-bismuth-based (139 ° C. eutectic) is preferable. That is, the solder is preferably free of lead, and is preferably a solder containing tin and indium, or a solder containing tin and bismuth.

  In order to further increase the bonding strength between the solder and the electrode, the solder in the conductive particles is nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, manganese And metals such as chromium, molybdenum and palladium. Further, from the viewpoint of further enhancing the bonding strength between the solder and the electrode, the solder in the conductive particles preferably contains nickel, copper, antimony, aluminum or zinc. From the viewpoint of further enhancing the bonding strength between the solder and the electrode in the solder portion or the conductive particles, the content of these metals for enhancing the bonding strength is preferably 0% in 100% by weight of the solder in the conductive particles. .0001% by weight or more, preferably 1% by weight or less.

  The melting point of the second conductive portion is preferably higher than the melting point of the solder portion. The melting point of the second conductive portion is preferably more than 160 ° C., more preferably more than 300 ° C., still more preferably more than 400 ° C., still more preferably more than 450 ° C., particularly preferably more than 500 ° C. Preferably it exceeds 600 ° C. The solder portion melts at the time of conductive connection because the melting point is low. It is preferable that the second conductive portion does not melt at the time of conductive connection. The conductive particles are preferably used by melting a solder, preferably by melting the solder portion, and used without melting the solder portion and the second conductive portion. Being preferred. When the melting point of the second conductive portion is higher than the melting point of the solder portion, it is possible to melt only the solder portion without melting the second conductive portion at the time of conductive connection.

  The absolute value of the difference between the melting point of the solder portion and the melting point of the second conductive portion is more than 0 ° C., preferably 5 ° C. or more, more preferably 10 ° C. or more, still more preferably 30 ° C. or more, particularly preferably Is 50.degree. C. or higher, most preferably 100.degree. C. or higher.

  The second conductive portion preferably contains a metal. The metal which comprises the said 2nd electroconductive part is not specifically limited. Examples of the metal include gold, silver, copper, platinum, palladium, zinc, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium and cadmium, and alloys thereof. Alternatively, tin-doped indium oxide (ITO) may be used as the metal. The metal may be used alone or in combination of two or more.

  The second conductive portion is preferably a nickel layer, a palladium layer, a copper layer or a gold layer, more preferably a nickel layer or a gold layer, and still more preferably a copper layer. The conductive particles preferably have a nickel layer, a palladium layer, a copper layer or a gold layer, more preferably a nickel layer or a gold layer, and still more preferably a copper layer. By using conductive particles having these preferred conductive portions for connection between electrodes, connection resistance between the electrodes is further reduced. In addition, solder portions can be more easily formed on the surfaces of these preferred conductive portions.

The thickness of the solder portion is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 10 μm or less, more preferably 1 μm or less, still more preferably 0.3 μm
It is below. When the thickness of the solder portion is not less than the above lower limit and not more than the above upper limit, sufficient conductivity is obtained, and the conductive particles are sufficiently deformed at the time of connection between the electrodes without the conductive particles becoming too hard. .

  The average particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, still more preferably 3 μm or more, particularly preferably 5 μm or more, preferably 100 μm or less, more preferably 60 μm or less, still more preferably 40 μm or less, more preferably 30 μm or less, still more preferably 20 μm or less, particularly preferably 15 μm or less, and most preferably 10 μm or less. When the average particle diameter of the conductive particles is at least the lower limit and the upper limit, the conductive particles can be arranged more efficiently on the electrode. The average particle diameter of the conductive particles is particularly preferably 3 μm or more and 30 μm or less.

  The “average particle size” of the conductive particles indicates a number average particle size. The average particle diameter of the conductive particles can be determined, for example, by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value or performing laser diffraction particle size distribution measurement.

  The coefficient of variation of the particle diameter of the conductive particles is preferably 5% or more, more preferably 10% or more, preferably 40% or less, more preferably 30% or less. The solder can be arranged more efficiently on the electrode as the variation coefficient of the particle diameter is not less than the lower limit and not more than the upper limit. However, the variation coefficient of the particle diameter of the conductive particles may be less than 5%.

  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 Dn: Average value of particle diameters of conductive particles

  The shape of the conductive particles is not particularly limited. The shape of the conductive particles may be spherical or may be a shape other than a spherical shape such as a flat shape.

  The content of the conductive particles is preferably 1% by weight or more, more preferably 2% by weight or more, still more preferably 10% by weight or more, particularly preferably 20% by weight or more, and most preferably 100% by weight of the conductive material. It is 30 wt% or more, preferably 80 wt% or less, more preferably 60 wt% or less, still more preferably 50 wt% or less. When the content of the conductive particles is at least the lower limit and the upper limit, the conductive particles can be more efficiently disposed on the electrode, and it is easy to dispose a large number of conductive particles between the electrodes. The conduction reliability is further enhanced. From the viewpoint of further enhancing the conduction reliability, it is preferable that the content of the conductive particles is large.

(Thermoplastic component)
The thermoplastic component is preferably a thermoplastic compound. Examples of the thermoplastic compound include phenoxy resin, urethane resin, (meth) acrylic resin, polyester resin, polyimide resin and polyamide resin. Only one type of the thermoplastic compound may be used, or two or more types may be used in combination.

  The content of the thermoplastic compound is preferably 20% by weight or more, more preferably 40% by weight or more, still more preferably 50% by weight or more, preferably 99% by weight or less, based on 100% by weight of the conductive material. It is at most 98 wt%, more preferably at most 90 wt%, particularly preferably at most 80 wt%. From the viewpoint of further improving the impact resistance, it is preferable that the content of the thermosetting component is large.

(Thermosetting compound: thermosetting component)
The thermosetting compound is a compound which can be cured by heating. Examples of the thermosetting compound include oxetane compounds, epoxy compounds, episulfide compounds, (meth) acrylic compounds, phenol compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicone compounds and polyimide compounds. Among them, epoxy compounds are preferable from the viewpoint of further improving the curability and viscosity of the conductive material and further enhancing the connection reliability.

  As said epoxy compound, an aromatic epoxy compound is mentioned. Crystalline epoxy compounds such as resorcinol type epoxy compounds, naphthalene type epoxy compounds, biphenyl type epoxy compounds and benzophenone type epoxy compounds are preferable. The epoxy compound which is solid at normal temperature (23 ° C.) and whose melting temperature is equal to or lower than the melting point of the solder is preferable. The melting temperature is preferably 100 ° C. or less, more preferably 80 ° C. or less, preferably 40 ° C. or more. By using the above-described preferable epoxy compound, when the connection target member is bonded, the viscosity is high, and when an impact such as transport is given an acceleration, the second connection is made with the first connection target member. Positional displacement with the target member can be suppressed, and the viscosity of the conductive material can be greatly reduced by heat at the time of curing, and aggregation of the solder particles can be efficiently advanced.

  The content of the thermosetting compound is preferably 20% by weight or more, more preferably 40% by weight or more, still more preferably 50% by weight or more, preferably 99% by weight or less, based on 100% by weight of the conductive material. Is preferably at most 98 wt%, more preferably at most 90 wt%, particularly preferably at most 80 wt%. From the viewpoint of further improving the impact resistance, it is preferable that the content of the thermosetting compound is large.

(Thermosetting agent: thermosetting component)
The thermosetting agent thermally cures the thermosetting compound. Examples of the thermosetting agent include imidazole curing agent, amine curing agent, phenol curing agent, polythiol curing agent, acid anhydride, thermal cation initiator, thermal radical generator and the like. Only one type of the thermosetting agent may be used, or two or more types may be used in combination.

  Imidazole curing agents, polythiol curing agents or amine curing agents are preferred, as the conductive material can be cured more rapidly at low temperatures. Moreover, since a storage stability becomes high when a thermosetting compound and the said thermosetting agent are mixed, a latent hardening agent is preferable. The latent curing agent is preferably a latent imidazole curing agent, a latent polythiol curing agent or a latent amine curing agent. The thermosetting agent may be coated with a polymeric substance such as a polyurethane resin or a polyester resin.

  The imidazole curing agent is not particularly limited, and 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2, 4-Diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine and 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s- The triazine isocyanuric acid adduct etc. are mentioned.

  The polythiol curing agent is not particularly limited, and examples thereof include trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate and dipentaerythritol hexa-3-mercaptopropionate. .

  The amine curing agent is not particularly limited, and hexamethylenediamine, octamethylenediamine, decamethylenediamine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraspiro [5.5] Undecane, bis (4-aminocyclohexyl) methane, metaphenylene diamine, diaminodiphenyl sulfone and the like can be mentioned.

  Examples of the thermal cationic curing agent include iodonium based cationic curing agents, oxonium based cationic curing agents, and sulfonium based cationic curing agents. Examples of the iodonium-based cationic curing agent include bis (4-tert-butylphenyl) iodonium hexafluorophosphate and the like. Examples of the oxonium-based cationic curing agent include trimethyloxonium tetrafluoroborate and the like. Examples of the sulfonium-based cationic curing agent include tri-p-tolylsulfonium hexafluorophosphate and the like.

  It does not specifically limit as said thermal radical generating agent, An azo compound, an organic peroxide, etc. are mentioned. Examples of the azo compound include azobisisobutyronitrile (AIBN) and the like. Examples of the organic peroxide include di-tert-butyl peroxide and methyl ethyl ketone peroxide.

  The reaction initiation temperature of the heat curing agent is preferably 50 ° C. or more, more preferably 70 ° C. or more, still more preferably 80 ° C. or more, preferably 250 ° C. or less, more preferably 200 ° C. or less, still more preferably 150 ° C. or less Particularly preferably, it is 140 ° C. or less. When the reaction initiation temperature of the thermosetting agent is above the lower limit and below the upper limit, solder is more efficiently disposed on the electrode. The reaction initiation temperature of the thermosetting agent is particularly preferably 80 ° C. or more and 140 ° C. or less.

  From the viewpoint of arranging the solder more efficiently on the electrode, the reaction initiation temperature of the heat curing agent is preferably higher than the melting point of the solder, more preferably 5 ° C. or more, more preferably 10 ° C. or more Is more preferred.

  The reaction initiation temperature of the thermosetting agent means the temperature at which the onset of the onset of the exothermic peak in DSC.

  The content of the thermosetting agent is not particularly limited. The content of the thermosetting agent is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, preferably 200 parts by weight or less, and more preferably 100 parts by weight with respect to 100 parts by weight of the thermosetting compound. Or less, more preferably 75 parts by weight or less. It is easy to fully harden a conductive material as content of a thermosetting agent is more than the above-mentioned minimum. When the content of the thermosetting agent is less than or equal to the above upper limit, it is difficult for the surplus thermosetting agent that did not participate in curing to remain after curing, and the heat resistance of the cured product is further enhanced.

(flux)
The conductive material and the binder preferably include a flux. The use of flux allows the solder to be placed more effectively on the electrodes. In addition, the appearance of the flux effect further reduces the connection resistance between the electrodes. The flux is not particularly limited. As the flux, a flux generally used for solder bonding can be used. Examples of the flux include zinc chloride, a mixture of zinc chloride and an inorganic halide, a mixture of zinc chloride and an inorganic acid, a molten salt, phosphoric acid, a derivative of phosphoric acid, an organic halide, hydrazine, an organic acid and rosin. Etc. Only one type of flux may be used, or two or more types may be used in combination.

  Ammonium chloride etc. are mentioned as said molten salt. Examples of the organic acids include lactic acid, citric acid, stearic acid, glutamic acid and glutaric acid. Examples of the rosin include activated rosin and non-activated rosin. The flux is preferably an organic acid having two or more carboxyl groups, or rosin. The flux may be an organic acid having two or more carboxyl groups, or may be rosin. The use of an organic acid having two or more carboxyl groups, or rosin, further enhances the conduction reliability between the electrodes.

  The above-mentioned rosins are rosins mainly composed of abietic acid. The flux is preferably rosins, more preferably abietic acid. The use of this preferred flux further enhances the conduction reliability between the electrodes.

  The activation temperature (melting point) of the flux is preferably 50 ° C. or more, more preferably 70 ° C. or more, still more preferably 80 ° C. or more, preferably 200 ° C. or less, more preferably 190 ° C. or less, still more preferably 160 ° C. or less More preferably, it is 150 ° C. or less, still more preferably 140 ° C. or less. The flux effect is exhibited more effectively as the activation temperature of the above-mentioned flux is more than the above-mentioned lower limit and below the above-mentioned upper limit, and solder is arranged more efficiently on an electrode. The activation temperature (melting point) of the flux is preferably 80 ° C. or more and 190 ° C. or less. The activation temperature (melting point) of the flux is particularly preferably 80 ° C. or more and 140 ° C. or less.

  The flux having an activation temperature (melting point) of 80 ° C. to 190 ° C. includes succinic acid (melting point 186 ° C.), glutaric acid (melting point 96 ° C.), adipic acid (melting point 152 ° C.), pimelic acid (melting point) C.), dicarboxylic acids such as suberic acid (melting point 142.degree. C.), benzoic acid (melting point 122.degree. C.), malic acid (melting point 130.degree. C.) and the like.

  Moreover, it is preferable that the boiling point of the said flux is 200 degrees C or less.

  From the viewpoint of arranging the solder more efficiently on the electrode, the melting point of the flux is preferably higher than the melting point of the solder, more preferably 5 ° C. or more, further preferably 10 ° C. or more .

  From the viewpoint of arranging the solder more efficiently on the electrode, the melting point of the flux is preferably higher than the reaction initiation temperature of the thermosetting agent, more preferably 5 ° C. or more, and more preferably 10 ° C. or more Is more preferred.

  The flux may be dispersed in the conductive material or may be deposited on the surface of the conductive particles.

  It is preferable that the said flux is a flux which discharge | releases a cation by heating. The use of a flux that releases cations upon heating allows the solder to be placed more efficiently on the electrodes.

  The content of the flux is preferably 0.5% by weight or more, preferably 30% by weight or less, and more preferably 25% by weight or less, based on 100% by weight of the conductive material. The conductive material may not contain flux. When the content of the flux is at least the above lower limit and the above upper limit, it is more difficult to form an oxide film on the surface of the solder and the electrode, and furthermore, the oxide film formed on the surface of the solder and the electrode is more effective Can be removed.

(Filler)
A filler may be added to the conductive material. The filler may be an organic filler or an inorganic filler. By the addition of the filler, the distance of the solder aggregation can be suppressed, and the conductive particles can be uniformly aggregated on all the electrodes of the substrate.

  The content of the filler is preferably 0% by weight (not contained) or more, preferably 5% by weight or less, more preferably 2% by weight or less, and still more preferably 1% by weight or less in 100% by weight of the conductive material. A solder is arrange | positioned much more efficiently on an electrode as content of the said filler is more than the said minimum and below the said upper limit.

(Other ingredients)
The conductive material may optionally be, for example, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, and a lubricant. And various additives such as an antistatic agent and a flame retardant may be included.

(Connection structure and manufacturing method of connection structure)
A connection structure according to the present invention includes a first connection target member having at least one first electrode on the surface, a second connection target member having at least one second electrode on the surface, and the first connection target member. And a connection portion connecting the second connection target member. In the connection structure according to the present invention, the connection portion is formed of the above-described conductive material. In the connection structure according to the present invention, the first electrode and the second electrode are electrically connected by the solder of the conductive particle. In the connection structure according to the present invention, the first electrode and the second electrode are electrically connected by the solder portion in the connection portion.

  A method of manufacturing a connection structure according to the present invention includes the step of disposing the conductive material on the surface of a first connection target member having at least one first electrode on the surface, using the above-described conductive material. A second connection target member having at least one second electrode on the surface on the surface opposite to the first connection target member side of the conductive material, the first electrode and the second connection target member A connection portion connecting the first connection target member and the second connection target member by heating the conductive material to a temperature higher than the melting point of the solder, and arranging the electrodes to face each other. And the step of electrically connecting the first electrode and the second electrode with the solder portion in the connection portion. Preferably, the conductive material is heated above the curing temperature of the thermosetting compound.

  In the connection structure according to the present invention and the method for producing the connection structure according to the present invention, since a specific conductive material is used, the solder is easily collected between the first electrode and the second electrode, and the solder is It can be efficiently arranged on the electrodes (lines). In addition, it is difficult for a part of the solder to be disposed in the area (space) in which the electrode is not formed, and the amount of the solder disposed in the area in which the electrode is not formed can be considerably reduced. Therefore, the conduction reliability between the first electrode and the second electrode can be enhanced. Moreover, electrical connection between laterally adjacent electrodes, which should not be connected, can be prevented, and insulation reliability can be enhanced.

  Further, in order to efficiently dispose the solder on the electrode and to considerably reduce the amount of the solder disposed in the area where the electrode is not formed, it is preferable to use a conductive paste instead of the conductive film.

  The thickness of the solder portion between the electrodes is preferably 10 μm or more, more preferably 20 μm or more, preferably 100 μm or less, more preferably 80 μm or less. The solder wet area on the surface of the electrode (the area in contact with the solder in 100% of the exposed area of the electrode) is preferably 50% or more, more preferably 70% or more, preferably 100% or less.

  In the method of manufacturing a connection structure according to the present invention, no pressure is applied in the step of arranging the second connection target member and the step of forming the connection portion, and the second connection is performed on the conductive material. It is preferable that the weight of the target member be added, and in the step of arranging the second connection target member and the step of forming the connection portion, the conductive material exceeds the force of the weight of the second connection target member. It is preferable not to apply an applied pressure. In these cases, the uniformity of the amount of solder can be further improved in the plurality of solder portions. Furthermore, the thickness of the solder portion can be further effectively increased, and a large amount of solder is easily collected between the electrodes, and the solder can be arranged more efficiently on the electrodes (lines). In addition, a part of the solder is difficult to be disposed in the area (space) in which the electrode is not formed, and the amount of the solder disposed in the area in which the electrode is not formed can be further reduced. Therefore, the conduction reliability between the electrodes can be further enhanced. In addition, the electrical connection between the laterally adjacent electrodes which should not be connected can be further prevented, and the insulation reliability can be further enhanced.

  In addition, if the conductive paste is used instead of the conductive film, the thickness of the connection portion and the solder portion can be easily adjusted by the application amount of the conductive paste. On the other hand, in the case of the conductive film, in order to change or adjust the thickness of the connection portion, it is necessary to prepare conductive films having different thicknesses or to prepare conductive films having a predetermined thickness. There is. In addition, in the case of the conductive film, it tends to be difficult to sufficiently lower the melt viscosity of the conductive film at the melting temperature of the solder, and there is a problem that the aggregation of the solder is easily inhibited.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing a connection structure obtained by using a conductive material according to an embodiment of the present invention.

  The connection structure 1 shown in FIG. 1 is a connection in which the first connection target member 2, the second connection target member 3, and the first connection target member 2 and the second connection target member 3 are connected. And 4 are provided. The connection portion 4 is formed of the above-described conductive material. In the present embodiment, the conductive material includes a plurality of conductive particles and a binder. In the present embodiment, the binder contains the above-mentioned thermosetting compound and the above-mentioned thermosetting agent. The thermosetting compound and the thermosetting agent are thermosetting components.

  The connection portion 4 includes a solder portion 4A in which a plurality of conductive particles are gathered and joined together, and a cured product portion 4B in which a thermosetting component is thermally cured.

  The first connection target member 2 has a plurality of first electrodes 2a on the surface (upper surface). The second connection target member 3 has a plurality of second electrodes 3a on the surface (lower surface). The first electrode 2a and the second electrode 3a are electrically connected by the solder portion 4A. Therefore, the first connection target member 2 and the second connection target member 3 are electrically connected by the solder portion 4A. In the connection portion 4, solder does not exist in a region (hardened portion 4 B portion) different from the solder portion 4 A collected between the first electrode 2 a and the second electrode 3 a. In a region (hardened portion 4B portion) different from the solder portion 4A, there is no solder separated from the solder portion 4A. If the amount is small, the solder may be present in a region (hardened portion 4B portion) different from the solder portion 4A collected between the first electrode 2a and the second electrode 3a.

As shown in FIG. 1, in the connection structure 1, after the plurality of conductive particles gather between the first electrode 2 a and the second electrode 3 a and the plurality of conductive particles are melted, the conductive particles are obtained. The molten metal of the above wets and spreads on the surface of the electrode and then solidifies to form a solder portion 4A. Therefore, the connection area between the solder portion 4A and the first electrode 2a, and between the solder portion 4A and the second electrode 3a is increased. That is, by using the conductive particles, the solder portion 4A, the first electrode 2a, and the solder are compared with the case where conductive particles whose outer surface is a metal such as nickel, gold or copper are used. The contact area between the portion 4A and the second electrode 3a is increased. For this reason, the conduction reliability and the connection reliability in the connection structure 1 become high. The conductive material may contain a flux. In the case of using a flux, heating generally causes the flux to be gradually inactivated.

  In the connection structure 1 shown in FIG. 1, all of the solder portions 4A are located in the area where the first and second electrodes 2a and 3a are facing each other. The connection structure 1X of the modified example shown in FIG. 3 differs from the connection structure 1 shown in FIG. 1 only in the connection part 4X. The connection portion 4X has a solder portion 4XA and a cured product portion 4XB. As in the connection structure 1X, most of the solder portions 4XA are located in the facing regions of the first and second electrodes 2a and 3a, and a part of the solder portions 4XA is the first and second portions. It may be protruded to the side from the field which electrode 2a, 3a has opposed. The solder portion 4XA protruding to the side from the opposing region of the first and second electrodes 2a and 3a is a part of the solder portion 4XA and is not the solder separated from the solder portion 4XA. In the present embodiment, the amount of solder separated from the solder portion can be reduced, but the solder separated from the solder portion may be present in the hardened material portion.

  The connection structure 1 can be easily obtained by reducing the amount of the conductive particles used. By increasing the amount of the conductive particles used, it becomes easy to obtain the connection structure 1X.

  From the viewpoint of further enhancing the conduction reliability, in the connection structures 1 and 1X, the first electrodes 2a and the second electrodes 2a in the stacking direction of the first electrodes 2a, the connection portions 4 and 4X, and the second electrodes 3a. The solder portion in the connection portion 4, 4X is 50% or more in the area 100% of the opposing portion of the first electrode 2a and the second electrode 3a when the opposing portion with the electrode 3a is viewed. Preferably, 4A and 4XA are arranged.

  From the viewpoint of further enhancing the conduction reliability, the facing portions of the first electrode and the second electrode are viewed in the stacking direction of the first electrode, the connection portion, and the second electrode. It is preferable that the solder portion in the connection portion be disposed at 50% or more of the area 100% of the opposing portion of the first electrode and the second electrode.

  From the viewpoint of further enhancing the conduction reliability, the first electrode and the second electrode face each other in the direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode. It is preferable that 70% or more of the solder portion in the connection portion be disposed in a portion where the first electrode and the second electrode face each other when the matching portion is viewed.

  Next, an example of a method of manufacturing the connection structure 1 using the conductive material according to an embodiment of the present invention will be described.

  First, the first connection target member 2 having the first electrode 2a on the surface (upper surface) is prepared. Next, as shown in FIG. 2A, the conductive material 11 including the thermosetting component 11B and the plurality of conductive particles 11A is disposed on the surface of the first connection target member 2 (first Process). The conductive material 11 is disposed on the surface of the first connection target member 2 on which the first electrode 2 a is provided. After the placement of the conductive material 11, the conductive particles 11A are placed both on the first electrode 2a (line) and on the area (space) where the first electrode 2a is not formed.

  The method of arranging the conductive material 11 is not particularly limited, but application by a dispenser, screen printing, discharge by an inkjet device, etc. may be mentioned.

In addition, the second connection target member 3 having the second electrode 3a on the surface (lower surface) is prepared. Next, as shown in FIG. 2B, in the conductive material 11 on the surface of the first connection target member 2, on the surface of the conductive material 11 on the opposite side to the first connection target member 2 side, The second connection target member 3 is disposed (second step). The second connection target member 3 is disposed on the surface of the conductive material 11 from the second electrode 3 a side. At this time, the first electrode 2a and the second electrode 3a are made to face each other.

  Next, the conductive material 11 is heated to a temperature equal to or higher than the melting point of the conductive particles 11A (third step). Preferably, the conductive material 11 is heated above the curing temperature of the thermosetting component 11B (binder). At the time of this heating, the conductive particles 11A present in the region where the electrode is not formed gather between the first electrode 2a and the second electrode 3a (self-aggregation effect). In this embodiment, since the conductive material is used instead of the conductive film, and the conductive material has a specific composition, the conductive particles 11A are made of the first electrode 2a and the second electrode 3a. Gather effectively between. Also, the conductive particles 11A melt and bond to each other. In addition, the thermosetting component 11B is thermally cured. As a result, as shown in FIG. 2C, the connection portion 4 connecting the first connection target member 2 and the second connection target member 3 is formed of the conductive material 11. The connection portion 4 is formed of the conductive material 11, and the plurality of conductive particles 11A are joined to form the solder portion 4A. The thermosetting component 11B is thermally cured to form the cured product portion 4B.

  In the present embodiment, it is preferable not to apply pressure in the second step and the third step. In this case, the weight of the second connection target member 3 is added to the conductive material 11. Therefore, at the time of formation of the connection portion 4, the conductive particles 11A effectively gather between the first electrode 2a and the second electrode 3a. Note that if pressing is performed in at least one of the second step and the third step, the action of collecting conductive particles between the first electrode and the second electrode is inhibited. The tendency to be This was found by the present inventor.

  However, pressurization may be performed as long as the distance between the first electrode and the second electrode can be secured. As a means for securing the distance between the electrodes, for example, a spacer corresponding to the desired distance between the electrodes may be added so that at least one, preferably three or more spacers are disposed between the electrodes. Examples of the spacer include inorganic particles and organic particles. The spacer is preferably an insulating particle.

  Further, in the present embodiment, since the pressurization is not performed, when the second connection target member is superimposed on the first connection target member coated with the conductive material, the electrode of the first connection target member Even when the first connection target member and the second connection target member are overlapped with each other in a state in which the electrodes of the second connection target member are misaligned, the shift is corrected to obtain the first connection target member. The second electrode and the second connection target member can be connected (self alignment effect). This is because the molten solder self-aggregated between the electrode of the first connection target member and the electrode of the second connection target member is the electrode of the first connection target member and the electrode of the second connection target member. As the area in which the solder in contact with the other components of the conductive material is in contact is the smallest is energy-stable, the force acting on the aligned connection structure, which is the connection structure with the smallest area, works. It is for. At this time, it is desirable that the conductive material is not cured, and that the viscosity of the components other than the conductive particles of the conductive material is sufficiently low at the temperature and time.

  Thus, the connection structure 1 shown in FIG. 1 is obtained. The second step and the third step may be performed continuously. Moreover, after performing the said 2nd process, the laminated body of the 1st connection object member 2, the conductive material 11, and the 2nd connection object member 3 obtained is moved to a heating part, and said 3rd A process may be performed. In order to perform the heating, the laminate may be disposed on a heating member, or the laminate may be disposed in a heated space.

  The heating temperature in the third step is preferably 140 ° C. or more, more preferably 160 ° C. or more, preferably 450 ° C. or less, more preferably 250 ° C. or less, still more preferably 200 ° C. or less.

  In addition, after the said 3rd process, a 1st connection object member or a 2nd connection object member can be peeled from a connection part for the purpose of correction of a position or rework of manufacture. The heating temperature for performing this peeling is preferably not less than the melting point of the conductive particles, more preferably not less than the melting point (° C.) of the conductive particles + 10 ° C. The heating temperature for performing this peeling may be the melting point (° C.) of the conductive particles plus 100 ° C. or less.

  As a heating method in the third step, a method of heating the entire connection structure by using a reflow furnace or using an oven at a temperature higher than the melting point of the conductive particles and a temperature higher than the curing temperature of the thermosetting component There is a method of locally heating only the connection part of the structure.

  As a tool used for the method of heating locally, a hot plate, a heat gun for applying hot air, a soldering iron, an infrared heater and the like can be mentioned.

  In addition, when heating locally with a hot plate, the metal directly under the connection should be a metal with high thermal conductivity, and other parts where heating is not desirable should be a material with low thermal conductivity such as fluorocarbon resin. Preferably, the upper surface of the hot plate is formed.

  The first and second connection target members are not particularly limited. Specifically, the first and second connection target members include semiconductor chips, semiconductor packages, LED chips, LED packages, electronic components such as capacitors and diodes, resin films, printed boards, flexible printed boards, flexible Examples include electronic components such as flat cables, rigid flexible substrates, glass epoxy substrates, and circuit substrates such as glass substrates. The first and second connection target members are preferably electronic components.

  It is preferable that at least one of the first connection target member and the second connection target member is a resin film, a flexible printed board, a flexible flat cable, or a rigid flexible board. It is preferable that the said 2nd connection object member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate. The resin film, the flexible printed circuit, the flexible flat cable and the rigid flexible substrate have properties of high flexibility and relatively light weight. When a conductive film is used to connect such a connection target member, the conductive particles tend to be difficult to collect on the electrode. On the other hand, even if a resin film, a flexible printed circuit, a flexible flat cable, or a rigid flexible substrate is used, the conduction reliability between the electrodes can be sufficiently improved by efficiently collecting the conductive particles on the electrodes. Can. When using a resin film, a flexible printed board, a flexible flat cable, or a rigid flexible board, compared with the case where other connection target members such as a semiconductor chip are used, reliability of conduction between electrodes by not applying pressure The improvement effect can be obtained more effectively.

As an electrode provided in the said connection object member, metal electrodes, such as a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode, a SUS electrode, and a tungsten electrode, are mentioned. When the connection target member is a flexible printed circuit, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, a silver 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, a silver 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 a metal oxide layer may be sufficient. As a material of the said metal oxide layer, the indium oxide in which the trivalent metal element was doped, the zinc oxide in which the trivalent metal element was doped, etc. are mentioned. Sn, Al, Ga, etc. are mentioned as said trivalent metal element.

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

  Thermosetting compound 1: 2,4-bis (glycidyloxy) benzophenone (crystalline thermosetting compound, melting point: 94 ° C., molecular weight 362)

Synthesis of 2,4-bis (glycidyloxy) benzophenone:
In a three-necked flask, 27 g of 2,4-dihydroxybenzophenone, 230 g of epichlorohydrin, 70 g of n-butanol and 1 g of tetraethylbenzylammonium chloride were added and dissolved at room temperature with stirring. Thereafter, the temperature was raised to 70 ° C. with stirring under a nitrogen atmosphere, and 45 g of an aqueous sodium hydroxide solution (concentration 48% by weight) was added dropwise under reflux under reduced pressure. The dripping was performed over 4 hours. Thereafter, the mixture was reacted at 70 ° C. for 2 hours while removing water using a Dean-Stark tube. Thereafter, unreacted epichlorohydrin was removed under reduced pressure.

  The resulting reaction product is dissolved in 400 g of a mixed solvent of MEK (methyl ethyl ketone): n-butanol 3: 1 (weight ratio), and 5 g of an aqueous solution of sodium hydroxide (concentration 10% by weight) is added. Heated for 2 hours.

  Then, it cooled to room temperature and wash | cleaned by the pure water until washing | cleaning liquid became neutral. The organic layer was separated with filtration, and the residual water and the mixed solvent were removed under reduced pressure to obtain a reaction product.

  34 g of the above reaction product was purified by recrystallization using n-hexane, and the residual solvent was removed by vacuum drying.

  Obtained epoxy compound: Melting point 94 ° C. by DSC, epoxy equivalent 176 g / eq. The molecular weight by mass spectrum was 362, and the melt viscosity at 150 ° C. was 5 mPa · s.

・ Differential scanning calorimetry (DSC) measuring apparatus and measuring conditions apparatus; “X-DSC7000” manufactured by Hitachi High-Tech Science, sample amount: 3 mg, temperature condition: 10 ° C./min
Melt viscosity at 150 ° C .: measured according to ASTM D 4287 using an ICI cone plate viscometer manufactured by MST Engineering, Inc. Measurement of epoxy equivalent: measured according to JIS K 7236: 2001 Measurement of molecular weight: mass spectrum Measurement using a GC-MS instrument ("JMS K-9" manufactured by Nippon Denshi Co., Ltd.)

  Thermosetting compound 2: 4,4'-bis (glycidyloxy) benzophenone (crystalline thermosetting compound, melting point: 132 ° C, molecular weight 362)

Synthesis of 4,4'-bis (glycidyloxy) benzophenone:
In a three-necked flask, 27 g of 4,4'-dihydroxybenzophenone, 230 g of epichlorohydrin, 70 g of n-butanol and 1 g of tetraethylbenzylammonium chloride were added and dissolved at room temperature with stirring. Thereafter, the temperature was raised to 70 ° C. with stirring under a nitrogen atmosphere, and 45 g of an aqueous sodium hydroxide solution (concentration 48% by weight) was added dropwise under reflux under reduced pressure. The dripping was performed over 4 hours. after that. The mixture was reacted at 70 ° C. for 2 hours while removing water using a Dean-Stark tube. Thereafter, unreacted epichlorohydrin was removed under reduced pressure.

  The resulting reaction product is dissolved in 400 g of a mixed solvent of MEK (methyl ethyl ketone): n-butanol 3: 1 (weight ratio), and 5 g of an aqueous solution of sodium hydroxide (concentration 10% by weight) is added. Heated for 2 hours.

  Then, it cooled to room temperature and wash | cleaned by the pure water until washing | cleaning liquid became neutral. The organic layer was separated with filtration, and the residual water and the mixed solvent were removed under reduced pressure to obtain a reaction product.

  34 g of the above reaction product was purified by recrystallization using n-hexane, and the residual solvent was removed by vacuum drying.

  Obtained epoxy compound: The melting point by DSC is 132 ° C., and the epoxy equivalent is 176 g / eq. The molecular weight by mass spectrum was 362, and the melt viscosity at 150 ° C. was 12 mPa · s.

  Thermosetting compound 3: Epoxy group-containing acrylic polymer, NOF Corporation "MARPROOF G- 0150M"

  Thermosetting agent 1: Pentaerythritol tetrakis (3-mercaptobutyrate), Showa Denko "Karens MT PE1"

  Latent epoxy thermosetting agent 1: "Fuji Cure 7000" manufactured by T & K TOKA

  Flux 1: Glutaric acid, manufactured by Wako Pure Chemical Industries, Ltd., melting point (activation temperature) 152 ° C.

Solder particle 1:
200 g of SnBi solder particles ("DS-10" manufactured by Mitsui Kinzoku Co., Ltd., average particle diameter (median diameter) 12 μm), 10 g of imidazole silane coupling agent ("SP-1000" manufactured by JX Nippon Mining & Metals Corporation), 70 g of acetone Was placed in a three-necked flask. The mixture was stirred under reflux at 60 ° C. for 5 hours under a nitrogen atmosphere to react the surface of the solder particle with the imidazole group of the imidazole silane coupling agent. Thereafter, the solution was cooled to room temperature, and the solder particles were filtered with filter paper, washed with acetone, and desolvated at room temperature for 1 hour by vacuum drying.

  The above solder particles are placed in a three-necked flask, and 70 g of acetone, 30 g of anhydrous adipic acid and 0.5 g of monobutyl tin oxide as a reaction catalyst are added thereto, and reacted under stirring at 60 ° C. for 3 hours under reflux in nitrogen atmosphere. The

  As a result, one carboxyl group derived from adipic anhydride is reacted with the silanol group derived from the silane coupling agent to cause covalent bonding. The other carboxyl group did not react, and the solder particle which has a carboxyl group on the surface was obtained.

  After cooling to room temperature, the solder particles are filtered with filter paper, and the solder particles are washed with acetone and hexane on the filter paper, unreacted, and non-covalently attached to the surface of the solder particles, After removing the residual anhydrous adipic acid, the solvent was removed by vacuum drying at room temperature for 1 hour. The obtained solder particles were crushed by a ball mill, and a sieve was selected so as to obtain a predetermined CV value.

  The obtained solder particles had an average particle size of 12 μm and a CV value of 20%.

  Solder particles A: SnBi solder particles ("DS-10" manufactured by Mitsui Kinzoku Co., Ltd., average particle diameter (median diameter) 12 μm)

(CV value of solder particle)
The CV value was measured with a laser diffraction type particle size distribution measuring apparatus ("LA-920" manufactured by Horiba, Ltd.).

(Examples 1 to 7 and Comparative Example 1)
The components shown in Table 1 below were blended in the amounts shown in Table 1 below to obtain an anisotropic conductive paste.

(1) Preparation of first connection structure (L / S = 50 μm / 50 μm) A glass epoxy substrate having a copper electrode pattern (copper electrode thickness 12 μm) of 50 μm / 50 μm with an electrode length of 3 mm at the top (FR-4 substrate) (first connection target member) was prepared. In addition, a flexible printed board (second connection target member) having a copper electrode pattern (copper electrode thickness 12 μm) of L / S 50 μm / 50 μm and electrode length 3 mm on the lower surface was prepared.

  The overlapping area of the glass epoxy substrate and the flexible printed substrate was 1.5 cm × 3 mm, and the number of connected electrodes was 75 pairs.

  On the top surface of the glass epoxy substrate, an anisotropic conductive paste immediately after preparation is applied by screen printing using a metal mask so as to have a thickness of 100 μm on the electrode of the glass epoxy substrate, and anisotropic conductive A paste layer was formed. Next, the said flexible printed circuit board was laminated | stacked so that electrodes might oppose on the upper surface of an anisotropic conductive paste layer. At this time, no pressure was applied. The weight of the flexible printed board is added to the anisotropic conductive paste layer. Thereafter, while heating so that the temperature of the anisotropic conductive paste layer is 190 ° C., the solder is melted, and the anisotropic conductive paste layer is cured at 190 ° C. and 10 seconds to form a first connection structure. Obtained.

(2) Preparation of second connection structure (L / S = 75 μm / 75 μm) A glass epoxy substrate having a copper electrode pattern (copper electrode thickness 12 μm) of L / S 75 μm / 75 μm and electrode length 3 mm on the top surface (FR-4 substrate) (first connection target member) was prepared. In addition, a flexible printed board (second connection target member) having a copper electrode pattern (copper electrode thickness 12 μm) of L / S 75 μm / 75 μm and electrode length 3 mm on the lower surface was prepared.

  A second connection structure was obtained in the same manner as the preparation of the first connection structure except that the above-described glass epoxy substrate and flexible printed substrate different in L / S were used.

(3) Preparation of third connection structure (L / S = 100 μm / 100 μm) A glass epoxy substrate having a copper electrode pattern (copper electrode thickness 12 μm) of L / S 100 μm / 100 μm, electrode length 3 mm on the top surface (FR-4 substrate) (first connection target member) was prepared. In addition, a flexible printed board (second connection target member) having a copper electrode pattern (copper electrode thickness 12 μm) of L / S 100 μm / 100 μm and electrode length 3 mm on the lower surface was prepared.

  A third connection structure was obtained in the same manner as the preparation of the first connection structure except that the above-described glass epoxy substrate and flexible printed substrate different in L / S were used.

(Evaluation)
(1) Viscosity The viscosity (η 25) at 25 ° C. of the anisotropic conductive paste was measured using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.) under conditions of 25 ° C. and 5 rpm.

(2) Thickness of Solder Portion By observing the obtained first connection structure in cross section, the thickness of the solder portion in which the upper and lower electrodes were positioned between was evaluated.

(3) Placement accuracy of solder on electrode 1
In the obtained first, second, and third connection structures, a portion where the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode is When viewed, the ratio X of the area in which the solder portion in the connection portion is disposed in the area 100% of the opposing portion of the first electrode and the second electrode was evaluated. The placement accuracy 1 of the solder on the electrode was determined based on the following criteria.

[Determination criteria of placement accuracy 1 of solder on electrode]
○ ○: Ratio X is 70% or more ○: Ratio X is 60% or more and less than 70% Δ: Ratio X is 50% or more and less than 60% ×: Ratio X is less than 50%

(4) Placement accuracy of solder on electrode 2
In the obtained first, second, and third connection structures, the first electrode and the second electrode are opposed in the direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode. The ratio Y of the soldered parts in the connecting part disposed at the opposing part of the first electrode and the second electrode in 100% of the soldered part in the connecting part was evaluated when the parts were seen. . The placement accuracy 2 of the solder on the electrode was determined based on the following criteria.

[Criteria for placement accuracy 2 of solder on electrodes]
○ ○: Ratio Y is 99% or more ○: Ratio Y is 90% or more and less than 99% Δ: Ratio Y is 70% or more and less than 90% ×: Ratio Y is less than 70%

(5) Conduction reliability between upper and lower electrodes In the obtained first, second and third connection structures (n = 15), the connection resistance per one connection point between the upper and lower electrodes is 4 It measured by the terminal method. The average value of connection resistance was calculated. The connection resistance can be determined from the relationship of voltage = current × resistance by measuring the voltage when a constant current flows. The conduction reliability was determined based on the following criteria.

[Criteria for continuity reliability]
○: Average value of connection resistance is 50 mΩ or less ○: Average value of connection resistance exceeds 50 mΩ and 70 mΩ or less Δ: Average value of connection resistance exceeds 70 mΩ and 100 mΩ or less ×: Average value of connection resistance exceeds 100 mΩ Or a bad connection has occurred

(6) Insulating reliability between adjacent electrodes in the lateral direction The obtained first, second and third connection structures (n = 15) were left for 1000 hours in an atmosphere at 85 ° C. and 85% humidity. After that, 15 V was applied between the electrodes adjacent in the lateral direction, and the resistance value was measured at 25 points. The insulation reliability was judged according to the following criteria.

[Criteria for insulation reliability]
○○: average value of connection resistance is 10 ⁷ Ω or more ○: average value of connection resistance is 10 ⁶ Ω or more and less than 10 ⁷ Ω Δ: average value of connection resistance is 10 ⁵ Ω or more and less than 10 ⁶ Ω ×: connection Average value of resistance is less than 10 ⁵ Ω

(7) Positional misalignment between upper and lower electrodes In the obtained first, second and third connection structures, the first electrode and the first connection direction in the stacking direction of the first electrode, the connection portion and the second electrode are used. When looking at the portion facing the two electrodes, it was evaluated whether the center line of the first electrode and the center line of the second electrode were aligned or not and the distance of displacement. The positional deviation between the upper and lower electrodes was determined according to the following criteria.

[Criteria for determining misalignment between upper and lower electrodes]
○: positional deviation less than 15 μm :: positional deviation greater than 15 μm and less than 25 μm Δ: positional deviation greater than 25 μm and less than 40 μm x: positional deviation greater than 40 μm

  The results are shown in Table 1 below.

  The same tendency was observed when using a resin film, a flexible flat cable and a rigid flexible substrate instead of the flexible printed substrate.

Reference Signs List 1, 1X Connection structure 2 First connection target member 2a First electrode 3 Second connection target member 3a Second electrode 4, 4X Connection portion 4A, 4XA Solder portion 4B, 4XB ... Hardened part 11 ... conductive material 11A ... solder particle 11 B ... thermosetting component 21 ... conductive particle (solder particle)
31 ... conductive particle 32 ... substrate particle 33 ... conductive portion (conductive portion having solder)
33A: second conductive portion 33B: solder portion 41: conductive particle 42: solder portion

Claims (8)

Containing a plurality of conductive particles and a binder,
The conductive particles are solder particles formed by solder,
The conductive particles have solder on the outer surface portion of the conductive portion,
The conductive particle has an imidazole ring and a group represented by the following formula (1) on the outer surface of the solder of the conductive portion,
The conductive material, wherein the imidazole ring is located between the outer surface of the solder and the group represented by the formula (1).

In said Formula (1), R1, R2 and R3 respectively represent an alkyl group, a hydroxyl group, an alkoxy group, or a carboxyl group containing group.   The conductive material according to claim 1, wherein the conductive particles are surface-treated with an imidazole silane coupling agent. The conductive particle is represented by an imidazole ring, a carbon chain having 4 to 12 carbon atoms of an ether chain or a linear portion, and an outer surface of the solder of the conductive portion, and the conductive particle represented by the formula (1) Have a base,
The conductive material according to claim 1, wherein the ether chain or the carbon chain is located between the imidazole ring and the group represented by the formula (1).   The conductive material according to any one of claims 1 to 3, wherein in the formula (1), at least one of R1, R2 and R3 represents a carboxyl group-containing group. The conductive material according to any one of claims 1 to 4 , wherein the binder comprises a thermosetting compound and a thermosetting agent. The conductive material according to any one of claims 1 to 5 , wherein an average particle diameter of the conductive particles is 1 μm or more and 60 μm or less. The conductive material according to any one of claims 1 to 6 , wherein a content of the conductive particles is 10 wt% or more and 80 wt% or less in 100 wt% of the conductive material. A first connection target member having a first electrode on the surface;
A second connection target member having a second electrode on its surface;
A connecting portion connecting the first connection target member and the second connection target member;
The connection portion is formed of the conductive material according to any one of claims 1 to 7 ,
The connection structure which the said 1st electrode and the said 2nd electrode are electrically connected by the solder in the said electroconductive particle.

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