JP2013014755A - Anisotropic conductive material, connecting structure and method for producing connecting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anisotropic conductive material which can enhance conduction reliability when used for electric connection between electrodes, and to provide a connecting structure using the anisotropic conductive material.SOLUTION: This anisotropic conductive material includes a curable compound, a photocationic curing agent, a heat curing agent and a conductive particle 5. The curable compound contains a curable compound having an epoxy group or thiirane group. The connecting structure 1 is equipped with a first connection target member 2 having a first electrode 2b on the upper surface 2a, a second connection target member 4 having a second electrode 4b on the lower surface 4a, and a connection part 3 electrically connecting the first and second connection target members 2, 4. The connection part 3 is formed by curing the anisotropic conductive material.

Description

  The present invention is an anisotropic conductive material including a plurality of conductive particles, for example, electrically connecting electrodes of various connection target members such as a flexible printed circuit board, a glass substrate, a glass epoxy substrate, and a semiconductor chip. The present invention relates to an anisotropic conductive material that can be used to make a connection, a connection structure using the anisotropic conductive material, and a method of manufacturing the connection structure.

  Pasty or film-like anisotropic conductive materials are widely known. In the anisotropic conductive material, a plurality of conductive particles are dispersed in a binder resin or the like.

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

  As an example of the anisotropic conductive material, the following Patent Document 1 includes a radical polymerizable substance (1), a polymerization initiator (2) that generates free radicals upon heating, an epoxy resin (3), and a cation. An anisotropic conductive material containing a polymerizable initiator (4) is disclosed. Examples of the radical polymerizable substance (1) include (meth) acrylate compounds having at least six skeletons of ethylene oxide and propylene oxide and two or more (meth) acryloyl groups. ing.

  In the following Patent Document 2, a polymer (A), a photocurable resin (B), a curing catalyst (C) for curing the photocurable resin (B), a reactive diluent (D), and An anisotropic conductive material containing conductive particles (E) is disclosed. The anisotropic conductive material has a viscosity at 23 ° C. of 5000 cps to 300000 cps.

JP 2006-127776 A JP-A-11-335641

  For example, when the electrode of the semiconductor chip and the electrode of the glass substrate are electrically connected by the anisotropic conductive material, an anisotropic conductive material containing conductive particles is disposed on the glass substrate. Next, the semiconductor chips are stacked, and heated and pressurized. As a result, the anisotropic conductive material is cured, and the electrodes are electrically connected via the conductive particles to obtain a connection structure.

  In the conventional anisotropic conductive material as described in Patent Documents 1 and 2, the anisotropic conductive material disposed on the glass substrate at the time of electrical connection between the electrodes and the anisotropic conductive material In some cases, the conductive particles contained in the fluid flow largely before curing. For this reason, the hardened | cured material layer and electroconductive particle formed with the anisotropic electrically-conductive material may not be arrange | positioned to a specific area | region. Furthermore, the conductive particles may not be disposed between the upper and lower electrodes to be connected, or adjacent electrodes that should not be connected may be electrically connected via a plurality of conductive particles. For this reason, the conduction | electrical_connection reliability in the connection structure obtained may be low.

  An object of the present invention is an anisotropic conductive material including a plurality of conductive particles, which can improve conduction reliability when used for electrical connection between electrodes, The present invention also provides a connection structure using the anisotropic conductive material and a method for manufacturing the connection structure.

  According to a wide aspect of the present invention, the curable compound includes a curable compound, a photocationic curing agent, a thermosetting agent, and conductive particles, and the curable compound includes a curable compound having an epoxy group or a thiirane group. An anisotropic conductive material is provided.

  In a specific aspect of the anisotropic conductive material according to the present invention, a photoradical initiator is further included.

  In another specific aspect of the anisotropic conductive material according to the present invention, the curable compound contains a curable compound having an unsaturated double bond.

  In still another specific aspect of the anisotropic conductive material according to the present invention, the curable compound contains a curable compound having an epoxy group or a thiirane group and having a (meth) acryloyl group.

  The anisotropic conductive material according to the present invention is preferably a paste-like anisotropic conductive paste.

  A connection structure according to the present invention includes a first connection target member, a second connection target member, and a connection part that electrically connects the first and second connection target members, The connecting portion is formed by curing the anisotropic conductive material described above.

  The method for manufacturing a connection structure according to the present invention includes a step of disposing an anisotropic conductive material layer using an anisotropic conductive material on a first connection target member having a first electrode on an upper surface, Curing is progressed by irradiating the anisotropic conductive material layer with light, and the anisotropic conductive material layer is converted into a B-stage, and an upper surface of the B-staged anisotropic conductive material layer is A step of further laminating a second connection target member having two electrodes on the lower surface, and a step of curing the B-staged anisotropic conductive material layer by heating, the anisotropic conductive material As described above, the anisotropic conductive material described above is used.

  In a specific aspect of the method for manufacturing a connection structure according to the present invention, in the step of forming the anisotropic conductive material layer into a B-stage, light is blocked by the conductive particles and is not directly irradiated with light. Curing of the isotropic conductive material layer portion is advanced by a cation reaction due to the action of the photocationic curing agent.

  An anisotropic conductive material according to the present invention includes a curable compound, a photocationic curing agent, a thermosetting agent, and conductive particles, and the curable compound includes a curable compound having an epoxy group or a thiirane group. Therefore, for example, after the anisotropic conductive material is favorably B-staged by light irradiation, the anisotropic conductive material that has been B-staged by heating can be fully cured. For this reason, the flow of the anisotropic conductive material and the conductive particles contained in the anisotropic conductive material can be suppressed by irradiating the anisotropic conductive material with light at an appropriate time. Therefore, the hardened | cured material layer and electroconductive particle formed with the anisotropic electrically-conductive material can be arrange | positioned in a specific area | region. Therefore, by using the anisotropic conductive material according to the present invention for the electrical connection between the electrodes, the conduction reliability between the electrodes in the connection structure can be enhanced.

FIG. 1 is a front sectional view schematically showing a connection structure using an anisotropic conductive material according to an embodiment of the present invention. 2A to 2C are front cross-sectional views for explaining each step of obtaining a connection structure using the anisotropic conductive material according to the embodiment of the present invention. FIG. 3 is a schematic diagram for explaining an anisotropic conductive material layer portion where light is blocked by conductive particles and light is not directly irradiated when the anisotropic conductive material layer is irradiated with light. . FIG. 4 is a schematic cross-sectional view for explaining a recess formed in the electrode.

  Hereinafter, the present invention will be described in detail.

  The anisotropic conductive material according to the present invention includes a curable compound, a photocationic curing agent, a thermosetting agent, and conductive particles. The curable compound contains a curable compound having an epoxy group or a thiirane group.

  By adopting the above composition in the anisotropic conductive material according to the present invention, curing of the anisotropic conductive material can be advanced by light irradiation. For example, after the anisotropic conductive material is well B-staged by light irradiation, the B-staged anisotropic conductive material can be fully cured by heating. For this reason, the flow of the anisotropic conductive material and the conductive particles contained in the anisotropic conductive material can be suppressed by irradiating the anisotropic conductive material with light at an appropriate time. In particular, when the anisotropic conductive material is irradiated with light, the light is blocked by the conductive particles and the light is not directly irradiated. The reaction can proceed sufficiently. As a result, the flow of the anisotropic conductive material and the conductive particles contained in the anisotropic conductive material is considerably suppressed.

  Therefore, the connection part and electroconductive particle formed with the anisotropic electrically-conductive material can be arrange | positioned in a specific area | region. For this reason, when the anisotropic conductive material which concerns on this invention is used for the electrical connection between electrodes, conduction | electrical_connection reliability can be improved.

  Hereinafter, first, the details of each component contained in the anisotropic conductive material according to the present invention will be described.

(Curable compound)
The curable compound contains a curable compound having an epoxy group or a thiirane group. The curable compound having an epoxy group is an epoxy compound. The curable compound having a thiirane group is an episulfide compound. As for the said curable compound which has an epoxy group or thiirane group, only 1 type may be used and 2 or more types may be used together.

  More preferably, the curable compound contains a curable compound having a thiirane group. Since the episulfide compound has a thiirane group instead of an epoxy group, it can be quickly cured at a low temperature. That is, the episulfide compound having a thiirane group can be cured at a lower temperature derived from the thiirane group as compared with the epoxy compound having an epoxy group.

  The curable compound having an epoxy group or thiirane group preferably has an aromatic ring. Examples of the aromatic ring include a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, tetracene ring, chrysene ring, triphenylene ring, tetraphen ring, pyrene ring, pentacene ring, picene ring, and perylene ring. Especially, it is preferable that the said aromatic ring is a benzene ring, a naphthalene ring, or an anthracene ring, and it is more preferable that it is a benzene ring or a naphthalene ring. A naphthalene ring is preferred because it has a planar structure and can be cured more rapidly.

  From the viewpoint of enhancing the curability of the anisotropic conductive material, the content of the curable compound having the epoxy group or thiirane group is preferably 10% by weight or more, more preferably 20% in 100% by weight of the curable compound. % By weight or more and 100% by weight or less. The total amount of the curable compound may be a curable compound having the epoxy group or thiirane group. When the curable compound having an epoxy group or thiirane group and another curable compound different from the curable compound having an epoxy group or thiirane group are used in combination, the epoxy is contained in 100% by weight of the curable compound. The content of the curable compound having a group or thiirane group is preferably 99% by weight or less, more preferably 95% by weight or less, still more preferably 90% by weight or less, and particularly preferably 80% by weight or less.

  The curable compound may further contain another curable compound different from the curable compound having an epoxy group or a thiirane group. Examples of the other curable compounds include curable compounds having an unsaturated double bond, phenol curable compounds, amino curable compounds, unsaturated polyester curable compounds, polyurethane curable compounds, silicone curable compounds, and polyimide curable compounds. Compounds and the like. As for said other curable compound, only 1 type may be used and 2 or more types may be used together.

  From the viewpoint of easily controlling the curing of the anisotropic conductive material or further improving the conduction reliability in the connection structure, the curable compound contains a curable compound having an unsaturated double bond. It is preferable to do. From the viewpoint of easily controlling the curing of the anisotropic conductive material and further improving the conduction reliability in the connection structure, the curable compound having an unsaturated double bond is a (meth) acryloyl group. It is preferable that it is a curable compound which has. By using the curable compound having the (meth) acryloyl group, it becomes easy to control the curing rate in each part of the B-staged anisotropic conductive material within a suitable range, and the resulting connected structure is electrically connected. Reliability becomes even higher.

  When a curable compound having an epoxy group or thiirane group and a curable compound having an unsaturated double bond such as a curable compound having a (meth) acryloyl group are used in combination, the dividend amount is not particularly limited. The content of the curable compound having an unsaturated double bond is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, and still more preferably with respect to 100 parts by weight of the curable compound having an epoxy group or thiirane group. It is 20 parts by weight or more, preferably 60 parts by weight or less, more preferably 50 parts by weight or less, and still more preferably 40 parts by weight or less.

  From the viewpoint of easily controlling the curing rate of the B-staged anisotropic conductive material layer and further improving the conduction reliability of the resulting connection structure, the curable compound having the (meth) acryloyl group is: It is preferable to have one or two (meth) acryloyl groups.

  The curable compound having the (meth) acryloyl group has no epoxy group and thiirane group, and has a (meth) acryloyl group, and has an epoxy group or thiirane group, and (meth) A curable compound having an acryloyl group may be mentioned.

  As the curable compound having the (meth) acryloyl group, an ester compound obtained by reacting a (meth) acrylic acid and a compound having a hydroxyl group, an epoxy obtained by reacting (meth) acrylic acid and an epoxy compound ( A (meth) acrylate, a urethane (meth) acrylate obtained by reacting a (meth) acrylic acid derivative having a hydroxyl group with an isocyanate, or the like is preferably used. The “(meth) acryloyl group” refers to an acryloyl group and a methacryloyl group. The “(meth) acryl” refers to acryl and methacryl. The “(meth) acrylate” refers to acrylate and methacrylate.

  The ester compound obtained by making the said (meth) acrylic acid and the compound which has a hydroxyl group react is not specifically limited. As the ester compound, any of a monofunctional ester compound, a bifunctional ester compound, and a trifunctional or higher functional ester compound can be used.

  The curable compound having an epoxy group or thiirane group and having a (meth) acryloyl group is a part of the epoxy group or part of thiirane group of the compound having two or more epoxy groups or two or more thiirane groups. It is preferable that it is a curable compound obtained by converting into a (meth) acryloyl group. This curable compound is a partially (meth) acrylated epoxy compound or a partially (meth) acrylated episulfide compound.

  The curable compound preferably contains a reaction product of a compound having two or more epoxy groups or two or more thiirane groups and (meth) acrylic acid. This reaction product is obtained by reacting a compound having two or more epoxy groups or two or more thiirane groups with (meth) acrylic acid in the presence of a basic catalyst according to a conventional method. It is preferable that 20% or more of the epoxy group or thiirane group is converted (converted) to a (meth) acryloyl group. The conversion is more preferably 30% or more, preferably 80% or less, more preferably 70% or less. Most preferably, 40% or more and 60% or less of the epoxy group or thiirane group is converted to a (meth) acryloyl group.

  Examples of the partially (meth) acrylated epoxy compound include bisphenol type epoxy (meth) acrylate, cresol novolac type epoxy (meth) acrylate, carboxylic acid anhydride-modified epoxy (meth) acrylate, and phenol novolac type epoxy (meth) acrylate. Is mentioned.

  As the curable compound, a modified phenoxy resin obtained by converting a part of epoxy groups of a phenoxy resin having two or more epoxy groups or two or more thiirane groups or a part of thiirane groups into a (meth) acryloyl group may be used. Good. That is, a modified phenoxy resin having an epoxy group or thiirane group and a (meth) acryloyl group may be used.

  The curable compound may be a crosslinkable compound or a non-crosslinkable compound.

  Specific examples of the crosslinkable compound include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, (poly ) Ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, glycerol methacrylate acrylate, pentaerythritol tri (meth) acrylate, tri Examples include methylolpropane trimethacrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, polyester (meth) acrylate, and urethane (meth) acrylate.

  Specific examples of the non-crosslinkable compound include ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) ) Acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (Meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, and the like.

(Thermosetting agent)
The said thermosetting agent is not specifically limited. A conventionally known thermosetting agent can be used as the thermosetting agent. Examples of the thermosetting agent include imidazole curing agents, amine curing agents, phenol curing agents, polythiol curing agents, and acid anhydrides. The thermosetting agent may be a thermosetting agent that is not a thermal radical initiator. As for the said thermosetting agent, only 1 type may be used and 2 or more types may be used together.

  Since the anisotropic conductive material can be cured more rapidly at a low temperature, the thermosetting agent is preferably an imidazole curing agent, a polythiol curing agent, or an amine curing agent. Moreover, since the storage stability of an anisotropic conductive material becomes high, a latent hardening | curing 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 polymer material such as polyurethane resin or 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- Examples include triazine isocyanuric acid adducts.

  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 hexamethylene diamine, octamethylene diamine, decamethylene diamine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraspiro [5.5]. Examples include undecane, bis (4-aminocyclohexyl) methane, metaphenylenediamine, and diaminodiphenylsulfone.

  The content of the thermosetting agent is not particularly limited. The content of the thermosetting agent with respect to 100 parts by weight of the thermosetting compound in the curable compound is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, and preferably 40 parts by weight or less. The amount is preferably 30 parts by weight or less, more preferably 20 parts by weight or less. When the content of the thermosetting agent is not less than the above lower limit and not more than the above upper limit, the anisotropic conductive material is sufficiently thermoset. The thermosetting compound is a curable compound that can be cured by heating.

(Photocationic curing agent)
Since the anisotropic conductive material which concerns on this invention contains a photocationic hardening agent, hardening of the anisotropic conductive material after light irradiation can be advanced rapidly. Furthermore, the anisotropic conductive material layer portion that is blocked by the conductive particles and not directly irradiated with light can be sufficiently cured by the cation reaction due to the action of the photocation curing agent.

  The photocationic curing agent is not particularly limited. As the photocationic curing agent, a conventionally known photocationic curing agent can be used. As for the said photocation hardening | curing agent, only 1 type may be used and 2 or more types may be used together.

  Examples of the photocationic curing agent include iodonium-based photocationic curing agents, oxonium-based photocationic curing agents, and sulfonium-based photocationic curing agents. Examples of the iodonium-based photocationic curing agent include bis (4-tert-butylphenyl) iodonium hexafluorophosphate. Examples of the oxonium-based photocationic curing agent include trimethyloxonium tetrafluoroborate. Examples of the sulfonium-based photocationic curing agent include tri-p-tolylsulfonium hexafluorophosphate and triphenylsulfonium bromide. Of these, a sulfonium-based photocationic curing agent is preferable from the viewpoint of further improving the curability of the anisotropic conductive material and further enhancing the conduction reliability between the electrodes.

  The content of the photocationic curing agent is not particularly limited. The content of the photocationic curing agent is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, preferably 2 parts per 100 parts by weight of the photocurable compound in the curable compound. It is 1 part by weight or less, more preferably 1 part by weight or less. When the content of the photocation curing agent is not less than the above lower limit and not more than the above upper limit, the anisotropic conductive material is appropriately photocured. By irradiating the anisotropic conductive material with light to form a B stage, the flow of the anisotropic conductive material can be suppressed. The photocurable compound is a curable compound that can be cured by light irradiation.

(Photo radical initiator)
The anisotropic conductive material preferably contains a photo radical initiator so that it can be more efficiently cured by light irradiation. Use of the photo radical initiator further increases the conduction reliability between the electrodes. The photo radical initiator is not particularly limited. A conventionally known photoradical initiator can be used as the photoradical initiator. As for the said photoradical initiator, only 1 type may be used and 2 or more types may be used together.

  The photo radical initiator is not particularly limited, and examples thereof include acetophenone photo radical initiator, benzophenone photo radical initiator, thioxanthone, ketal photo radical initiator, halogenated ketone, acyl phosphinoxide, and acyl phosphonate.

  Specific examples of the acetophenone photoradical initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, methoxy Examples include acetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, and 2-hydroxy-2-cyclohexylacetophenone. Specific examples of the ketal photoradical initiator include benzyldimethyl ketal.

  The content of the photo radical initiator is not particularly limited. The content of the photo radical initiator with respect to 100 parts by weight of the photocurable compound in the curable compound is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, preferably 2 parts. It is 1 part by weight or less, more preferably 1 part by weight or less. When the content of the photo radical initiator is not less than the above lower limit and not more than the above upper limit, the anisotropic conductive material is appropriately photocured. By irradiating the anisotropic conductive material with light to form a B stage, the flow of the anisotropic conductive material can be suppressed.

  Moreover, it is preferable that the compounding ratio of the said photocationic curing agent and the said photoradical initiator is 0.01: 99.99-99.99-0.01 by weight ratio, and 1: 99-99: 1. Is more preferably 5:95 to 95: 5, and particularly preferably 20:80 to 80:20.

(Conductive particles)
The conductive particles contained in the anisotropic conductive material electrically connect the electrodes of the first and second connection target members. The conductive particles are not particularly limited as long as they are conductive particles. The surface of the conductive layer of the conductive particles may be covered with an insulating layer. In this case, the insulating layer between the conductive layer and the electrode is excluded when the connection target member is connected. Examples of the conductive particles include organic particles, inorganic particles other than metal particles, organic-inorganic hybrid particles, or conductive particles whose surfaces are covered with a metal layer, or metals that are substantially composed only of metal. Particles and the like. The metal layer is not particularly limited. Examples of the metal layer include a gold layer, a silver layer, a copper layer, a nickel layer, a palladium layer, or a metal layer containing tin.

  From the viewpoint of increasing the contact area between the electrode and the conductive particle and further improving the conduction reliability between the electrodes, the conductive particle includes a resin particle and a conductive layer disposed on the surface of the resin particle. It is preferable to have. From the viewpoint of further improving the conduction reliability between the electrodes, the conductive particles are preferably conductive particles having at least an outer conductive surface as a low melting point metal layer. More preferably, the conductive particles include resin particles and a conductive layer disposed on the surface of the resin particles, and at least the outer surface of the conductive layer is a low melting point metal layer.

  The low melting point metal layer is a layer containing a low melting point metal. The low melting point metal is a metal having a melting point of 450 ° C. or lower. The melting point of the low melting point metal is preferably 300 ° C. or lower, more preferably 160 ° C. or lower. The low melting point metal layer preferably contains tin. In 100% by weight of the metal contained in the low melting point metal layer, the content of tin is preferably 30% by weight or more, more preferably 40% by weight or more, still more preferably 70% by weight or more, and particularly preferably 90% by weight or more. is there. When the content of tin in the low-melting-point metal layer is not less than the above lower limit, the connection reliability between the low-melting-point metal layer and the electrode is further enhanced. The tin content is determined using a high frequency inductively coupled plasma optical emission spectrometer (“ICP-AES” manufactured by Horiba, Ltd.) or a fluorescent X-ray analyzer (“EDX-800HS” manufactured by Shimadzu). It can be measured.

  When the outer surface of the conductive layer is a low melting point metal layer, the low melting point metal layer is melted and joined to the electrodes, and the low melting point metal layer conducts between the electrodes. For example, since the low-melting point metal layer and the electrode are not in point contact but in surface contact, the connection resistance is lowered. In addition, the use of conductive particles having at least the outer surface of a low-melting-point metal layer increases the bonding strength between the low-melting-point metal layer and the electrode. , The conduction reliability is effectively increased.

  The low melting point metal which comprises the said low melting metal layer is not specifically limited. The low melting point metal is preferably tin or an alloy containing tin. Examples of the alloy include a tin-silver alloy, a tin-copper alloy, a tin-silver-copper alloy, a tin-bismuth alloy, a tin-zinc alloy, and a tin-indium alloy. Especially, since it is excellent in the wettability with respect to an electrode, it is preferable that the said low melting metal is a tin, a tin-silver alloy, a tin-silver-copper alloy, a tin-bismuth alloy, and a tin-indium alloy. More preferred are a tin-bismuth alloy and a tin-indium alloy.

  The low melting point metal layer is preferably a solder layer. Although the material which comprises the said solder layer is not specifically limited, Based on JISZ3001: welding term, it is preferable that it is a filler material whose liquidus is 450 degrees C or less. As a composition of the said solder layer, the metal composition containing zinc, gold | metal | money, lead, copper, tin, bismuth, indium etc. is mentioned, for example. Among them, a tin-indium system (117 ° C. eutectic) or a tin-bismuth system (139 ° C. eutectic) which is low-melting and lead-free is preferable. That is, the solder layer preferably does not contain lead, and is preferably a solder layer containing tin and indium or a solder layer containing tin and bismuth.

  In order to further increase the bonding strength between the low melting point metal layer and the electrode, the low melting point metal layer is made of nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth. Further, it may contain a metal such as manganese, chromium, molybdenum and palladium. From the viewpoint of further increasing the bonding strength between the low melting point metal and the electrode, the low melting point metal preferably contains nickel, copper, antimony, aluminum, or zinc. From the viewpoint of further increasing the bonding strength between the low melting point metal layer and the electrode, the content of these metals for increasing the bonding strength is 100 wt% of the low melting point metal layer, preferably 0.0001 wt% or more, Preferably it is 1 weight% or less.

  The conductive particles include resin particles and a conductive layer disposed on the surface of the resin particles, and the outer surface of the conductive layer is a low melting point metal layer (such as a solder layer). In addition to the low melting point metal layer, a second conductive layer is preferably provided between the low melting point metal layer and the low melting point metal layer. In this case, the low melting point metal layer is a part of the entire conductive layer, and the second conductive layer is a part of the entire conductive layer.

  The second conductive layer different from the low melting point metal layer preferably contains a metal. The metal constituting the second conductive layer is not particularly 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. Further, tin-doped indium oxide (ITO) may be used as the metal. As for the said metal, only 1 type may be used and 2 or more types may be used together.

  The second conductive layer 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 even 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 have a nickel layer or a gold layer, and still more preferably have a copper layer. By using the conductive particles having these preferable conductive layers for the connection between the electrodes, the connection resistance between the electrodes is further reduced. In addition, a low melting point metal layer can be more easily formed on the surface of these preferable conductive layers. The second conductive layer may be a low melting point metal layer such as a solder layer. The conductive particles may have a plurality of low melting point metal layers.

  The average particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 100 μm or less, more preferably 20 μm or less, still more preferably 15 μm or less, and particularly preferably 10 μm or less. When the average particle diameter of the conductive particles is not less than the above lower limit and not more than the above upper limit, even if the anisotropic conductive material layer portion where light is blocked by the conductive particles and not directly irradiated with light, photocationic curing Curing can sufficiently proceed by a cationic reaction due to the action of the agent. Moreover, the average particle diameter of the said electroconductive particle may exceed 5 micrometers, and may be 10 micrometers or more. From the viewpoint of further improving the connection reliability of the connection structure when subjected to a thermal history, the average particle diameter of the conductive particles is particularly preferably 1 μm or more and 10 μm or less, and is 1 μm or more and 4 μm or less. Most preferred.

  The “average particle size” of the conductive particles indicates a number average particle size. The average particle diameter of the conductive particles can be obtained by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value.

  The resin particles can be properly used depending on the electrode size or land diameter of the substrate to be mounted.

  From the viewpoint of more reliably connecting the upper and lower electrodes and further suppressing the short circuit between the electrodes adjacent in the lateral direction, the ratio of the average particle diameter C of the conductive particles to the average particle diameter A of the resin particles ( C / A) is more than 1.0, preferably 3.0 or less. In addition, when the second conductive layer is present between the resin particles and the solder layer, the ratio of the resin particles to the average particle size B with respect to the average particle size B of the conductive particle portion excluding the solder layer (B / A) is greater than 1.0, preferably 2.0 or less. Further, when there is the second conductive layer between the resin particles and the solder layer, the average particle diameter B of the conductive particle portion excluding the solder layer having the average particle diameter C of the conductive particles including the solder layer. The ratio (C / B) to is more than 1.0, preferably 2.0 or less. When the ratio (B / A) is within the above range or the ratio (C / B) is within the above range, electrodes that are more reliably connected between the upper and lower electrodes and that are adjacent in the lateral direction The short circuit between them can be further suppressed.

  The content of the conductive particles is not particularly limited. In 100% by weight of the anisotropic conductive material, the content of the conductive particles is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, still more preferably 1% by weight or more, preferably 40% by weight. % Or less, more preferably 30% by weight or less, still more preferably 19% by weight or less. A conductive particle can be easily arrange | positioned between the upper and lower electrodes which should be connected as content of the said electroconductive particle is more than the said minimum and below the said upper limit. Furthermore, it becomes difficult to electrically connect adjacent electrodes that should not be connected via a plurality of conductive particles. That is, a short circuit between adjacent electrodes can be further prevented.

(Other ingredients)
The anisotropic conductive material preferably contains a filler. By using the filler, latent heat expansion of the cured product of the anisotropic conductive material can be suppressed. Specific examples of the filler include silica, aluminum nitride, and alumina. As for a filler, only 1 type may be used and 2 or more types may be used together.

  The anisotropic conductive material preferably contains a curing accelerator. By using a curing accelerator, the curing rate can be further increased. As for a hardening accelerator, only 1 type may be used and 2 or more types may be used together.

  Specific examples of the curing accelerator include imidazole curing accelerators and amine curing accelerators. Of these, imidazole curing accelerators are preferred. In addition, an imidazole hardening accelerator or an amine hardening accelerator can be used also as an imidazole hardening agent or an amine hardening agent.

  The anisotropic conductive material may contain a solvent. By using the solvent, the viscosity of the anisotropic conductive material can be easily adjusted. Examples of the solvent include ethyl acetate, methyl cellosolve, toluene, acetone, methyl ethyl ketone, cyclohexane, n-hexane, tetrahydrofuran, and diethyl ether.

(Connection structure and method of manufacturing connection structure)
A connection structure can be obtained by connecting the connection target members using the anisotropic conductive material according to the present invention.

  The connection structure includes a first connection target member, a second connection target member, and a connection portion that electrically connects the first and second connection target members. The part is formed by curing the anisotropic conductive material. The connection portion is a cured product layer obtained by curing the anisotropic conductive material.

  Next, a connection structure using an anisotropic conductive material according to an embodiment of the present invention and a method for manufacturing the connection structure will be described in more detail with reference to the drawings.

  In FIG. 1, an example of the connection structure using the anisotropic conductive material which concerns on one Embodiment of this invention is typically shown with front sectional drawing.

  A connection structure 1 shown in FIG. 1 includes a first connection target member 2, a second connection target member 4, and a connection part 3 connecting the first and second connection target members 2 and 4. Prepare. The connection part 3 is a cured product layer. The connecting portion 3 is formed by curing an anisotropic conductive material including a curable compound, a photocationic curing agent, a thermosetting agent, and conductive particles 5. The curable compound contained in the anisotropic conductive material contains a curable compound having an epoxy group or a thiirane group. The anisotropic conductive material includes a plurality of conductive particles 5.

  The first connection target member 2 has a plurality of first electrodes 2b on the upper surface 2a (front surface). The second connection target member 4 has a plurality of second electrodes 4b on the lower surface 4a (front surface). The first electrode 2 b and the second electrode 4 b are electrically connected by one or a plurality of conductive particles 5.

  In the connection structure 1, a glass substrate is used as the first connection target member 2, and a semiconductor chip is used as the second connection target member 4. The first and second connection target members are not particularly limited. Specifically, the first and second connection target members include electronic components such as semiconductor chips, capacitors, and diodes, and electronic components that are circuit boards such as printed boards, flexible printed boards, glass boards, and glass epoxy boards. Etc. The anisotropic conductive material is preferably an anisotropic conductive material used for connecting electronic components. The anisotropic conductive material is a paste-like anisotropic conductive paste, and the anisotropic conductive paste is preferably applied on the connection target member in a paste state.

  The connection structure 1 shown in FIG. 1 can be obtained as follows, for example.

  As shown to Fig.2 (a), the 1st connection object member 2 which has the 1st electrode 2b in the upper surface 2a is prepared. Next, the upper surface 2a of the first connection object member 2 includes a curable compound, a photocationic curing agent, a thermosetting agent, and conductive particles 5, and the curable compound has an epoxy group or a thiirane group. An anisotropic conductive material layer 3 </ b> A is disposed on the upper surface 2 a of the first connection target member 2 using an anisotropic conductive material containing a compound. At this time, it is preferable that one or a plurality of conductive particles 5 be arranged on the first electrode 2b. When an anisotropic conductive paste is used as the anisotropic conductive material, the anisotropic conductive paste is arranged by applying the anisotropic conductive paste. The anisotropic conductive material layer becomes an anisotropic conductive paste layer.

  Next, the anisotropic conductive material layer 3A is cured by irradiating the anisotropic conductive material layer 3A with light. By curing the anisotropic conductive material layer 3A, the anisotropic conductive material layer 3A is B-staged. As shown in FIG. 2B, the anisotropic conductive material layer 3 </ b> B having the B stage is formed on the upper surface 2 a of the first connection target member 2 by forming the anisotropic conductive material layer 3 </ b> A into the B stage. .

  The thickness (average thickness) of the anisotropic conductive material layer 3A and the B-staged anisotropic conductive material layer 3B is preferably 10 μm or more, and preferably 100 μm or less. In the COG application, the thickness (average thickness) of the anisotropic conductive material layer 3A and the B-staged anisotropic conductive material layer 3B is preferably 10 μm or more, more preferably 15 μm or more, and preferably 30 μm or less. Preferably it is 25 micrometers or less. In FOG use, the thickness (average thickness) of the anisotropic conductive material layer 3A and the B-staged anisotropic conductive material layer 3B is preferably 30 μm or more, more preferably 40 μm or more, and preferably 70 μm or less. Preferably it is 60 micrometers or less.

  In the step of forming the anisotropic conductive material layer 3A into the B-stage, the anisotropic conductive material layer portion 3Bb (see FIG. 3, conductive particles 5) where light is blocked by the conductive particles 5 and light X is not directly irradiated. Is preferably advanced by a cation reaction by the action of the photocationic curing agent. Thereby, the flow of the anisotropic conductive material layer and the conductive particles contained in the anisotropic conductive material layer is considerably suppressed. As a result, the conduction reliability between the electrodes is considerably increased.

  When the anisotropic conductive material layer 3A is cured to make the anisotropic conductive material layer 3A into a B-stage, the anisotropic conductive material 5 is irradiated with light X without being blocked by the conductive particles 5. The curing rate (1) of the material layer portion 3Ba (see FIG. 3, the region excluding the portion between the two broken lines below the conductive particles 5) is set to 20% or more, and the light is blocked by the conductive particles 5. The curing rate (2) of the anisotropic conductive material layer portion 3Bb (see FIG. 3, the region between the two broken lines below the conductive particles 5) that was not directly irradiated with X should be less than 20%. preferable. By controlling the curing rates (1) and (2) of the anisotropic conductive material layer portions 3Ba and 3Bb as described above, the components other than the conductive particles in the anisotropic conductive material layer are removed from the electrode and the conductive particles. The electrode and the conductive particles can be effectively brought into contact with each other. In particular, components other than the conductive particles 5 in the anisotropic conductive material layer 3B existing between the conductive particles 5 and the first electrode 2b can be effectively excluded. Furthermore, by controlling the curing rates (1) and (2) of the anisotropic conductive material layer portions 3Ba and 3Bb as described above, it is possible to form the recesses in which the conductive particles are pushed into the electrodes. As shown in FIG. 4, it is also possible to form a recess 2c in the first electrode 2b by pushing in the conductive particles 5. Therefore, the conduction | electrical_connection reliability between electrodes in the connection structure obtained can be improved.

  Further, by controlling the curing rates (1) and (2) of the anisotropic conductive material layer portions 3Ba and 3Bb as described above, the flow of the conductive particles contained in the anisotropic conductive material layer can be sufficiently increased. Can be suppressed. That is, the flow rate of the conductive particles can be sufficiently suppressed by relatively increasing the curing rate (1) of the anisotropic conductive material layer portion 3Ba having a curing rate equal to or higher than the lower limit. For this reason, it becomes easy to arrange conductive particles between the electrodes. Furthermore, it can suppress that an electroconductive particle flows unintentionally to the area | region of the side rather than the outer peripheral surface of a 1st connection object member or a 2nd connection object member. For this reason, conduction | electrical_connection reliability can be improved when the electrodes of the 1st, 2nd connection object member are electrically connected. For example, the upper and lower electrodes to be connected can be easily connected with conductive particles, and adjacent electrodes that should not be connected can be prevented from being connected via a plurality of conductive particles.

  In order to effectively increase the conduction reliability between the electrodes in the connection structure, the curing rate (1) of the anisotropic conductive material layer portion 3Ba is preferably 20% or more, more preferably 22% or more, and still more preferably. Is 25% or more, particularly preferably 30% or more and 100% or less.

  In order to effectively enhance the conduction reliability between the electrodes in the connection structure, the curing rate (2) of the anisotropic conductive material layer portion 3Bb is preferably 20% or less, more preferably less than 20%, and still more preferably. Is 15% or less, preferably 5% or more.

  In order to effectively increase the conduction reliability between the electrodes in the connection structure, the curing rate (1) of the anisotropic conductive material layer portion 3Ba and the cure rate (2) of the anisotropic conductive material layer portion 3Bb are: The absolute value of the difference is more than 0%, preferably 5% or more, more preferably 10% or more. The upper limit of the absolute value of the difference is not particularly limited. The absolute value of the difference may be 50% or less, 35% or less, or 30% or less.

  In the present specification, the curing rate means a value calculated from the following formula (X) by measuring the functional group amount of a reactive functional group using IR (infrared spectroscopy).

  Curing rate (%) = (1- (functional group amount of anisotropic conductive material after light irradiation / functional group amount of anisotropic conductive material before light irradiation)) × 100 Formula (X)

  The anisotropic conductive material after light irradiation in the above formula (X) is a B-staged anisotropic conductive material.

  It is preferable to irradiate the anisotropic conductive material layer 3A with light while disposing the anisotropic conductive material on the upper surface 2a of the first connection target member 2. Furthermore, it is also preferable to irradiate the anisotropic conductive material layer 3 </ b> A simultaneously with or immediately after the placement of the anisotropic conductive material on the upper surface 2 a of the first connection target member 2. When the arrangement and the light irradiation are performed as described above, the flow of the anisotropic conductive material layer 3A can be further suppressed. For this reason, the conduction | electrical_connection reliability in the obtained connection structure 1 becomes still higher. The time from the placement of the anisotropic conductive material on the upper surface 2a of the first connection target member 2 to the irradiation with light is 0 second or longer, preferably 3 seconds or shorter, more preferably 2 seconds or shorter.

In order to make the anisotropic conductive material layer 3A into a B-stage by light irradiation, the light irradiation intensity for appropriately proceeding curing of the anisotropic conductive material layer 3A is, for example, preferably 0.1 to 10000 mW / it is cm ^2. Moreover, the irradiation energy of light for appropriately proceeding the curing of the anisotropic conductive material layer 3A is, for example, preferably about 100 to 10,000 mJ / cm ² .

  The light source used when irradiating light is not specifically limited. Examples of the light source include a light source having a sufficient light emission distribution at a wavelength of 420 nm or less. Specific examples of the light source include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, a metal halide lamp, and an LED lamp.

  Next, as shown in FIG. 2C, the second connection target member 4 is laminated on the upper surface 3a of the B-staged anisotropic conductive material layer 3B. The second connection target member 4 is laminated so that the first electrode 2b on the upper surface 2a of the first connection target member 2 and the second electrode 4b on the lower surface 4a of the second connection target member 4 face each other. To do.

  Further, when the second connection target member 4 is laminated, the anisotropic conductive material layer 3B is further cured by applying heat to the anisotropic conductive material layer 3B, so that the connection portion 3 is formed. However, heat may be applied to the anisotropic conductive material layer 3B before the second connection target member 4 is laminated. After the lamination of the second connection target member 4, it is preferable to apply heat to the anisotropic conductive material layer 3B to completely cure it.

  When the anisotropic conductive material layer 3B is cured by applying heat, the heating temperature for sufficiently curing the anisotropic conductive material layer 3B is preferably 160 ° C or higher, preferably 250 ° C or lower, more preferably It is 200 degrees C or less.

  It is preferable to apply pressure when the anisotropic conductive material layer 3B is cured. By compressing the conductive particles 5 with the first electrode 2b and the second electrode 4b by pressurization, the contact area between the first and second electrodes 2b, 4b and the conductive particles 5 is increased. For this reason, conduction reliability increases.

  By curing the anisotropic conductive material layer 3 </ b> B, the first connection target member 2 and the second connection target member 4 are connected via the connection portion 3. Further, the first electrode 2 b and the second electrode 4 b are electrically connected through the conductive particles 5. In this way, the connection structure 1 shown in FIG. 1 can be obtained. In this embodiment, since photocuring and thermosetting are used together, the anisotropic conductive material can be cured in a short time.

  The anisotropic conductive material may be an anisotropic conductive film or an anisotropic conductive paste. The anisotropic conductive material is preferably a paste-like anisotropic conductive paste. When the anisotropic conductive paste is used, the conductive particles tend to flow and the conduction reliability tends to be lower than when the anisotropic conductive film is used. By adopting the composition in the anisotropic conductive material according to the present invention, even if an anisotropic conductive paste is used, the conduction reliability can be sufficiently increased.

  The anisotropic conductive material according to the present invention and the manufacturing method of the connection structure according to the present invention include, for example, a connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), a semiconductor chip and a flexible printed circuit board. Can be used for connection (COF (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)), etc. . Especially, the manufacturing method of the anisotropic conductive material which concerns on this invention, and the connection structure which concerns on this invention is suitable for a COG or FOG use, and is more suitable for a COG use. In the anisotropic conductive material according to the present invention and the method for manufacturing the connection structure according to the present invention, it is preferable to use a semiconductor chip and a glass substrate as the first connection target member and the second connection target member. . A flexible printed circuit board and a glass substrate may be used as the first connection target member and the second connection target member.

  In FOG applications, since the L / S is relatively wide, the particle size of the conductive particles is large and the concentration is low, so the pressure at the time of connection is low, sufficient indentation and resin filling properties cannot be obtained, and conduction reliability between electrodes And the occurrence of voids in the cured product layer is often a problem. On the other hand, the use of the curable composition according to the present invention can effectively increase the conduction reliability between the electrodes in the FOG application, and effectively generate voids in the cured product layer. Can be suppressed.

  In COG applications, in particular, it is often difficult to reliably connect the electrodes of the semiconductor chip and the glass substrate with conductive particles of an anisotropic conductive material. For example, in the case of COG use, the distance between adjacent electrodes of a semiconductor chip and the distance between adjacent electrodes of a glass substrate may be about 10 to 20 μm, and fine wiring is often formed. Even if fine wiring is formed, the semiconductor particles can be accurately disposed between the electrodes by the anisotropic conductive material according to the present invention and the manufacturing method of the connection structure according to the present invention. And the glass substrate can be connected with high accuracy, and the conduction reliability can be improved.

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

Example 1
(1) Preparation of anisotropic conductive paste An episulfide compound (1B) represented by the following formula (1B) was prepared.

  15 parts by weight of the above-mentioned episulfide compound (1B), 4 parts by weight of an amine adduct (“PN-23J” manufactured by Ajinomoto Fine Techno Co.) which is a thermosetting agent, and 8 parts by weight of epoxy acrylate (“EBECRYL 3702” manufactured by Daicel-Cytec) And 0.5 part by weight of tri-p-tolylsulfonium hexafluorophosphate (manufactured by Tokyo Chemical Industry Co., Ltd.) which is a photocationic curing agent, and an acylphosphine oxide compound (manufactured by Ciba Japan Co., Ltd.) which is a photoradical initiator. DAROCUR TPO ") 0.2 parts by weight, 1 part by weight of 2-ethyl-4-methylimidazole as a curing accelerator, and 10 parts by weight of alumina (average particle size 0.5 μm) as a filler, Conductive particles A (average particle diameter 10 μm, nickel plating layer on the surface of divinylbenzene resin particles And having a metal layer with a gold plating layer formed on the surface of the nickel plating layer) was added so that the content in 100% by weight of the anisotropic conductive paste was 3% by weight. Then, anisotropic conductive paste was obtained by stirring for 5 minutes at 2000 rpm using a planetary stirrer.

(2) Production of Connection Structure A transparent glass substrate (first connection target member) having an Al-4% Ti electrode pattern with an L / S of 50 μm / 50 μm formed on the upper surface was prepared. Moreover, the flexible printed circuit board (2nd connection object member) by which the copper electrode pattern whose L / S is 50 micrometers / 50 micrometers and the electrode area per electrode is 500000 micrometers ² was formed in the lower surface was prepared.

On the transparent glass substrate, the obtained anisotropic conductive paste was applied to a thickness of 50 μm to form an anisotropic conductive paste layer. Next, using an ultraviolet irradiation lamp, ultraviolet rays are incident on the anisotropic conductive paste layer perpendicularly to the main surface of the anisotropic conductive paste layer so that the irradiation energy is 1000 mJ / cm ^2. Ultraviolet rays were irradiated from above, and the anisotropic conductive paste layer was semi-cured by photopolymerization to form a B stage. Next, the flexible printed circuit board was laminated on the anisotropic conductive paste layer so that the electrodes face each other. Then, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer becomes 185 ° C., a pressure heating head is placed on the upper surface of the flexible printed circuit board and a pressure of 1 MPa is applied to apply the anisotropic conductive paste layer. Was completely cured at 185 ° C. to obtain a connection structure.

(Example 2)
An anisotropic conductive paste was obtained in the same manner as in Example 1 except that the photocationic curing agent was changed to triphenylsulfonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) during the preparation of the anisotropic conductive paste. . A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Example 3)
An anisotropic conductive paste was obtained in the same manner as in Example 1 except that no photoradical initiator was added during the preparation of the anisotropic conductive paste. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

Example 4
In the preparation of the anisotropic conductive paste, the conductive particles A (average particle size 10 μm) are the conductive particles B (average particle size 20 μm, the nickel plating layer is formed on the surface of the divinylbenzene resin particles, and An anisotropic conductive paste was obtained in the same manner as in Example 1 except that the surface of the nickel plating layer was changed to (having a metal layer on which a gold plating layer was formed). A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Example 5)
In the preparation of the anisotropic conductive paste, the conductive particles A (average particle size 10 μm) are the same as the conductive particles C (average particle size 30 μm, the nickel plating layer is formed on the surface of the divinylbenzene resin particles, and An anisotropic conductive paste was obtained in the same manner as in Example 1 except that the surface of the nickel plating layer was changed to (having a metal layer on which a gold plating layer was formed). A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Example 6)
In the preparation of the anisotropic conductive paste, in the same manner as in Example 1 except that the conductive particles A were used so that the content in 100% by weight of the anisotropic conductive paste was 5% by weight. An anisotropic conductive paste was obtained. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Example 7)
In the preparation of the anisotropic conductive paste, in the same manner as in Example 1 except that the conductive particles A were used so that the content in 100% by weight of the anisotropic conductive paste was 10% by weight. An anisotropic conductive paste was obtained. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Example 8)
An anisotropic conductive paste was obtained in the same manner as in Example 1 except that the epoxy acrylate was changed to urethane acrylate ("EBECRYL8804" manufactured by Daicel-Cytec Co., Ltd.) during the preparation of the anisotropic conductive paste. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

Example 9
Anisotropic conductive paste was prepared in the same manner as in Example 1 except that the epoxy acrylate was changed to tricyclodecane dimethanol diacrylate (“IRR-214K” manufactured by Daicel-Cytec). A conductive paste was obtained. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Example 10)
An episulfide compound (2B) represented by the following formula (2B) was prepared.

  An anisotropic conductive paste was obtained in the same manner as in Example 1 except that the episulfide compound (1B) was changed to the episulfide compound (2B) during the preparation of the anisotropic conductive paste. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Example 11)
An anisotropic conductive paste was obtained in the same manner as in Example 1 except that the amount of the epoxy acrylate was changed to 0.75 parts by weight when preparing the anisotropic conductive paste. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Example 12)
An anisotropic conductive paste was obtained in the same manner as in Example 1 except that the amount of the epoxy acrylate was changed to 9 parts by weight when preparing the anisotropic conductive paste. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Comparative Example 1)
In the preparation of the anisotropic conductive paste, in the same manner as in Example 1, except that tri-p-tolylsulfonium hexafluorophosphate (manufactured by Tokyo Chemical Industry Co., Ltd.), which is a photocationic curing agent, was not blended. An anisotropic conductive paste was obtained. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Comparative Example 2)
In the preparation of the anisotropic conductive paste, epoxy acrylate, tri-p-tolylsulfonium hexafluorophosphate (manufactured by Tokyo Chemical Industry Co., Ltd.) as a photocationic curing agent, and acylphosphine oxide system as a photoradical initiator An anisotropic conductive paste was obtained in the same manner as in Example 1 except that the compound was not blended. In 100% by weight of the obtained anisotropic conductive paste, the content of the conductive particles A was 3% by weight.

A transparent glass substrate (first connection target member) on which an Al-4% Ti electrode pattern having an L / S of 50 μm / 50 μm was formed was prepared. Moreover, the flexible printed circuit board (2nd connection object member) by which the copper electrode pattern whose L / S is 50 micrometers / 50 micrometers and the electrode area per electrode is 500000 micrometers ² was formed in the lower surface was prepared.

  On the transparent glass substrate, the obtained anisotropic conductive paste was applied to a thickness of 50 μm to form an anisotropic conductive paste layer. No light was applied during and after application of the anisotropic conductive paste.

  Next, the flexible printed circuit board was laminated on the upper surface of the anisotropic conductive paste layer so that the electrodes face each other. Then, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer becomes 185 ° C., a pressure heating head is placed on the upper surface of the flexible printed circuit board and a pressure of 1 MPa is applied to apply the anisotropic conductive paste layer. Was completely cured at 185 ° C. to obtain a connection structure.

(Evaluation)
(1) Curing Rate The curing rate in the B-staged anisotropic conductive paste layer formed during the manufacture of the connection structure was evaluated.

  Curing rate (1) of the anisotropic conductive paste layer portion irradiated with light without being blocked by the conductive particles, and anisotropy where the light was blocked by the conductive particles and not directly irradiated with the light The curing rate (2) of the conductive paste layer portion was measured. When measuring, the light is blocked by the conductive particles and the curing rate (1) at any five positions of the anisotropic conductive paste layer irradiated with light without being blocked by the conductive particles. The cure rate (2) at any five locations of the anisotropic conductive paste layer portion that was not directly irradiated was measured, and the average value of the measured values was taken as the cure rate.

(2) Indentation state About the connection part of 100 electroconductive particles and an electrode in the obtained connection structure, the state of the indentation formed in the electrode was observed.

Using a polarizing microscope, it was judged that good indentations were formed when an average of 25 or more spherical indentations per electrode (per 500,000 μm ² ) could be confirmed. Moreover, it was judged that formation of an indentation was inadequate when the average of less than five spherical indentations per electrode (per 500,000 μm ² ) was confirmed. The indentation state was determined according to the following criteria.

[Indentation criteria]
○○: Average of 25 or more spherical indentations in 100 connected portions ○: Average of 10 or more and less than 25 indentations in 100 connected portions Δ: In 100 connected portions The average spherical indentation is 5 or more and less than 10 on average. ×: The average number of obvious spherical indentations is less than 5 in 100 connecting portions.

(3) Conduction reliability (conductivity test between upper and lower electrodes)
The connection resistance between the upper and lower electrodes of the obtained connection structure was measured by a four-terminal method. The average value of the connection resistance at 100 locations was calculated. Note that the connection resistance can be obtained by measuring the voltage when a constant current is passed from the relationship of voltage = current × resistance.

  The results are shown in Table 1 below.

DESCRIPTION OF SYMBOLS 1 ... Connection structure 2 ... 1st connection object member 2a ... Upper surface 2b ... 1st electrode 2c ... Recessed part 3 ... Connection part 3a ... Upper surface 3A ... Anisotropic conductive material layer 3B ... B staged anisotropy Conductive material layer 3Ba, 3Bb ... B-staged anisotropic conductive material layer portion 4 ... Second connection target member 4a ... Lower surface 4b ... Second electrode 5 ... Conductive particles

Claims (8)

Including a curable compound, a photocationic curing agent, a thermosetting agent, and conductive particles,
An anisotropic conductive material, wherein the curable compound contains a curable compound having an epoxy group or a thiirane group.   The anisotropic conductive material according to claim 1, further comprising a photoradical initiator.   The anisotropic conductive material according to claim 1, wherein the curable compound contains a curable compound having an unsaturated double bond.   The anisotropic conductive material of any one of Claims 1-3 in which the said curable compound contains the curable compound which has an epoxy group or thiirane group, and has a (meth) acryloyl group.   The anisotropic conductive material according to claim 1, which is a paste-like anisotropic conductive paste. A first connection target member, a second connection target member, and a connection part that electrically connects the first and second connection target members;
The connection structure in which the said connection part is formed by hardening the anisotropic conductive material of any one of Claims 1-5. Disposing an anisotropic conductive material layer using an anisotropic conductive material on a first connection target member having a first electrode on an upper surface;
Curing the anisotropic conductive material layer by irradiating it with light, and making the anisotropic conductive material layer a B-stage;
A step of further laminating a second connection target member having a second electrode on the lower surface on the upper surface of the B-staged anisotropic conductive material layer;
Curing the B-staged anisotropic conductive material layer by heating,
The manufacturing method of a connection structure using the anisotropic conductive material of any one of Claims 1-5 as said anisotropic conductive material.   In the step of converting the anisotropic conductive material layer into a B-stage, light is blocked by the conductive particles and the anisotropic conductive material layer portion that is not directly irradiated with light is cured by the action of the photocationic curing agent. The manufacturing method of the connection structure of Claim 7 made to advance by the cation reaction by.

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