JP5886582B2 - Anisotropic conductive material, B-stage cured product, method for producing B-stage cured product, and connection structure - Google Patents

Description

  The present invention relates to an anisotropic conductive material including a plurality of conductive particles, and is used for electrical connection between 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 cured, a B-stage-shaped cured product obtained by curing the anisotropic conductive material, and a connection structure using the anisotropic conductive material or the B-stage cured product.

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

  Specifically, the anisotropic conductive material is used for connection between an IC chip and a flexible printed circuit board, connection between an IC chip and a circuit board having an ITO electrode, and the like. For example, after an anisotropic conductive material is arranged between the electrode of the IC chip and the electrode of the circuit board, these electrodes can be connected by heating and pressurizing.

  As an example of the anisotropic conductive material, Patent Document 1 below includes an epoxy resin, rubber-like polymer particles, a thermally active latent epoxy curing agent, high softening point polymer particles, and conductive particles. An anisotropic conductive material is disclosed.

JP 2000-345010 A

  For example, when an electrode of a semiconductor chip and an electrode of a glass substrate are electrically connected by a conventional anisotropic conductive material as described in Patent Document 1, for example, a different particle containing conductive particles is formed on the glass substrate. An isotropic conductive material is disposed. 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, the anisotropic conductive material disposed on the glass substrate and the conductive particles contained in the anisotropic conductive material may flow greatly before curing. In particular, with respect to conventional anisotropic conductive materials, even when curing of the anisotropic conductive material proceeds to the B-stage state, the conductive particles easily move, and the conductive particles in the B-stage state are more conductive. The part not including the particles may be relatively large. For this reason, the hardened | cured material layer and electroconductive particle formed with the anisotropic electrically-conductive material may be unable to be arrange | positioned in 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 of the obtained connection structure may be low.

  An object of the present invention is to provide an anisotropic conductive material and a B-stage-like cured product capable of improving conduction reliability when used for electrical connection between electrodes, and the anisotropic conductive material or B stage. It is providing the connection structure using a hardened | cured material.

  According to a wide aspect of the present invention, an anisotropic conductive material containing at least three curable compounds and conductive particles, the curable compound being an epoxy group or a thiirane group and a (meth) acryloyl group. A thermosetting compound having an epoxy group or a thiirane group and having no (meth) acryloyl group, no epoxy group and no thiirane group, and (meth) A photocurable compound having an acryloyl group, and the light and thermosetting compound having the epoxy group or thiirane group and the (meth) acryloyl group have a weight average molecular weight of less than 100,000, An anisotropic conductive material is provided in which when the B-stage-shaped cured product is obtained by proceeding with curing, the B-stage-shaped cured product has a sea-island structure.

  According to another broad aspect of the present invention, there is provided a B-stage-shaped cured product obtained by irradiating an anisotropic conductive material with light to advance the curing of the anisotropic conductive material. The material contains at least three curable compounds and conductive particles, and the curable compound has an epoxy group or a thiirane group and a (meth) acryloyl group, and an epoxy group. Or a thermosetting compound having a thiirane group and not having a (meth) acryloyl group, and a photocurable compound not having an epoxy group and a thiirane group and having a (meth) acryloyl group, There is provided a B-stage-shaped cured product having a sea-island structure in which the light- and thermosetting compound having an epoxy group or thiirane group and a (meth) acryloyl group has a weight average molecular weight of less than 100,000.

  In a specific aspect of the anisotropic conductive material and B-stage cured product according to the present invention, a thermosetting agent and a photopolymerization initiator are further included.

  The 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 an anisotropic conductive material configured according to the present invention, or by curing a B-stage-shaped cured product obtained by proceeding with the curing of the anisotropic conductive material. Is formed.

  The anisotropic conductive material according to the present invention contains at least three curable compounds and conductive particles, and the curable compound has light and heat having an epoxy group or a thiirane group and a (meth) acryloyl group. Photo-curing having a curable compound, a thermosetting compound having an epoxy group or thiirane group and not having a (meth) acryloyl group, and having no (meth) acryloyl group having no epoxy group and thiirane group Therefore, the anisotropic conductive material can be cured by light irradiation and heating. Specifically, the anisotropic conductive material can be cured in two stages by semi-curing the anisotropic conductive material by light irradiation and then thermosetting.

  Furthermore, since the B stage-shaped cured product obtained by proceeding photocuring of the anisotropic conductive material according to the present invention and the B stage-shaped cured product according to the present invention have a sea-island structure, in the state of the B stage-shaped cured product The flow and settling of the conductive particles can be suppressed. Moreover, since the size of the sea-island structure can be controlled, it is possible to suppress the portion where the conductive particles are not included from becoming too large in the state of the B-stage-shaped cured product.

  Therefore, when the electrodes of the first and second connection target members are electrically connected using the anisotropic conductive material according to the present invention, conduction reliability can be improved. 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.

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.

  Hereinafter, the present invention will be described in detail.

  The anisotropic conductive material according to the present invention contains at least three curable compounds (hereinafter sometimes referred to as curable compound A) and conductive particles. The curable compound A includes a light and thermosetting compound having an epoxy group or thiirane group and a (meth) acryloyl group (hereinafter sometimes referred to as light and thermosetting compound A1), an epoxy group or thiirane. A thermosetting compound having a group and not having a (meth) acryloyl group (hereinafter sometimes referred to as thermosetting compound A2), an epoxy group and a thiirane group, and (meth) And a photocurable compound having an acryloyl group (hereinafter sometimes referred to as photocurable compound A3). The weight average molecular weight of the light and thermosetting compound A1 having the epoxy group or thiirane group and the (meth) acryloyl group is less than 100,000.

  The anisotropic conductive material according to the present invention preferably further includes a thermosetting agent and a photopolymerization initiator. The thermosetting agent and the photopolymerization initiator may be added in advance to the anisotropic conductive material, or may be added to the anisotropic conductive material when the anisotropic conductive material is used.

  Moreover, the B-stage-shaped cured product obtained by irradiating the anisotropic conductive material according to the present invention with light and causing the curing of the anisotropic conductive material has a sea-island structure. Moreover, the B-stage-shaped cured product according to the present invention has a sea-island structure.

  The “sea-island structure” refers to a structure in which sea components and island components exist in a phase-separated state, and island components are dispersed in the sea component.

  One of the main features of the present invention is that, in the state of the B-stage cured product, the B-stage cured product has a sea-island structure. By forming such a sea-island structure, the flow and settling of conductive particles can be remarkably suppressed in the B-stage cured product. Therefore, it is easy to dispose conductive particles in specific areas by suppressing the flow and settling of conductive particles by simply curing the anisotropic conductive material by light irradiation to make a B-stage-like cured product. Is possible. This is presumably because the movement of the conductive particles is hindered at the interface between the sea component and the island component. Moreover, by producing the connection structure through the state of the B-stage cured product, the fluidity of the anisotropic conductive material before curing can be reduced, and the flow of the anisotropic conductive material can be suppressed. For this reason, 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, when the electrodes of the connection target members are electrically connected using the anisotropic conductive material, the conduction reliability can be improved. Specifically, for example, the conductive particles can be arranged more reliably between the upper and lower electrodes to be connected. Further, the agglomerated conductive particles make it difficult for the electrodes adjacent in the lateral direction that should not be connected to be connected to each other, and it is possible to suppress a short circuit between the adjacent electrodes.

  Another main feature of the present invention is that the curable compound A has a light and thermosetting compound A1 having an epoxy group or thiirane group and a (meth) acryloyl group, an epoxy group or thiirane group, and A thermosetting compound A2 having no (meth) acryloyl group, and a photocurable compound A3 having no epoxy group and thiirane group and having a (meth) acryloyl group. By using the at least three kinds of curable compounds A, the B-stage-shaped cured product does not have a sea-island structure, but has a good sea-island structure.

  When the anisotropic conductive material is irradiated with light to cause photocuring to proceed, the curing of the photocurable compound A3 is relatively easy to proceed before the curing of the light and the thermosetting compound A1. That is, since the photo-curing property of the light and thermosetting compound A1 and the photo-curing property of the photo-curable compound A3 are in an appropriate relationship, an island portion is formed in the portion where the curing of the photo-curable compound A3 has progressed, Expansion of an island part is inhibited by light and thermosetting compound A1, and it can control that an island part in a sea island structure becomes large too much. For example, it is easy to make the size of the island part (island component) less than 20 μm, and it can be made 10 μm or less. As a result, in the state of the B-stage-shaped cured product, not only can the flow and sedimentation of the conductive particles be suppressed, but also the portion not including the conductive particles can be suppressed from becoming too large, and the connection structure The conduction reliability of the body can be increased. In addition, when an island part is formed in the part which hardening of photocurable compound A3 advanced, electroconductive particle is easy to be contained in the sea part instead of an island part. The “size of the island part” indicates the maximum diameter in one island part.

  On the other hand, when only the photocurable compound A3 is used without using the light and thermosetting compound A1, the island portion is likely to be easily enlarged, and the portion not including the conductive particles is likely to be enlarged. Is difficult to form. In addition, for example, when the curing of an anisotropic conductive material including a conventional epoxy compound and a (meth) acrylic compound is advanced, the island portion is likely to be easily enlarged, and there is a portion that does not include conductive particles. It tends to be large and it is difficult to form a good sea-island structure. Furthermore, when only light and thermosetting compound A1 are used without using photocurable compound A3, it is difficult to sufficiently suppress the flow and settling of conductive particles.

In the anisotropic conductive material according to the present invention, preferably, an anisotropic conductive material having a thickness of 20 μm is irradiated with light so that the irradiation energy of light is 50 mW / cm ² , thereby curing the anisotropic conductive material. When the B stage cured product is obtained by being advanced, the B stage cured product has a sea-island structure.

  The anisotropic conductive material according to the present invention is preferably an anisotropic conductive material that cures the B-stage-shaped cured product after curing proceeds to obtain a B-stage-shaped cured product. In addition, the anisotropic conductive material according to the present invention is an anisotropic conductive material that cures by light irradiation to obtain a B-stage cured product, and then cures the B-stage cured product by heating. It is preferable.

  Hereinafter, the detail of each component contained in the anisotropic conductive material which comprises the anisotropic conductive material which concerns on this invention, and the B stage-shaped hardened | cured material which concerns on this invention is demonstrated.

[Curable compound]
The anisotropic conductive material includes at least three curable compounds A.

  The curable compound A is a light and thermosetting compound A1 having an epoxy group or thiirane group and a (meth) acryloyl group, and a thermosetting having an epoxy group or a thiirane group and not having a (meth) acryloyl group. And a photocurable compound A3 having no (meth) acryloyl group and having no epoxy group or thiirane group. The light and thermosetting compound A1 has photocurability and thermosetting. The thermosetting compound A2 has thermosetting properties. The photocurable compound A3 has photocurability.

  The said curable compound may contain curable compounds other than light and thermosetting compound A1, thermosetting compound A2, and photocurable compound A3.

  In 100% by weight of the curable compound A in the anisotropic conductive material, the total content of the light and thermosetting compound A1, the thermosetting compound A2 and the photocurable compound A3 is preferably 50% by weight or more, more preferably Is 70% by weight or more and 100% by weight or less. The total amount of curable compound A may be a mixture of light and thermosetting compound A1, thermosetting compound A2 and photocurable compound A3. When the total content of the light and thermosetting compound A1, the thermosetting compound A2, and the photocurable compound A3 is equal to or more than the above lower limit, an even better sea-island structure can be formed.

Details of the light and thermosetting compound A1:
The weight average molecular weight of the curable compound A1 having an epoxy group or thiirane group and a (meth) acryloyl group is less than 100,000, preferably 50,000 or less, and more preferably 10,000 or less. The smaller the weight average molecular weight of the light and thermosetting compound A1, the more effectively small islands can be formed, and therefore a good sea-island structure can be formed. For this reason, the conduction | electrical_connection reliability of a connection structure becomes still higher. In addition, the minimum of the weight average molecular weight of light and the thermosetting compound A1 is not specifically limited. The weight average molecular weight of the light and thermosetting compound A1 is generally 50 or more.

  In this specification, “weight average molecular weight” means that when the light and thermosetting compound A1 is not a polymer and when the structural formula of the light and thermosetting compound A1 can be specified, It means the molecular weight that can be calculated. Moreover, when light and the thermosetting compound A1 are polymers, it means a weight average molecular weight.

  The light and thermosetting compound A1 having the epoxy group or thiirane group and the (meth) acryloyl group is 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 the light and thermosetting compound obtained by converting into a (meth) acryloyl group. Such light and thermosetting compounds are partially (meth) acrylated epoxy compounds or partially (meth) acrylated episulfide compounds.

  The light and thermosetting compound A1 is preferably 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. 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.

  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.

  A modified phenoxy resin obtained by converting a part of epoxy groups or a part of thiirane groups of a phenoxy resin having two or more epoxy groups or two or more thiirane groups into a (meth) acryloyl group as the light and thermosetting compound A1. It may be used. That is, a modified phenoxy resin having an epoxy group or thiirane group and a (meth) acryloyl group may be used.

Details of thermosetting compound A2:
The thermosetting compound A2 having an epoxy group or thiirane group and having no (meth) acryloyl group may be a compound having an epoxy group or a compound having a thiirane group. The compound having an epoxy group is an epoxy compound. The compound having a thiirane group is an episulfide compound.

  From the viewpoint of easily controlling the curing of the anisotropic conductive material or further improving the conduction reliability of the connection structure, the curable compound A contains at least one of an epoxy compound and an episulfide compound. It is more preferable that it contains an episulfide compound.

  The epoxy compound and the episulfide compound preferably have 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.

  Since the episulfide compound has a thiirane group instead of an epoxy group, it can be cured quickly 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.

  From the viewpoint of curing more rapidly at a low temperature, the episulfide compound is an episulfide compound having a structure represented by the following formula (1-1), (2-1), (3), (7) or (8). It is preferable that it is an episulfide compound having a structure represented by the following formula (1-1), (2-1) or (3). In the following formula (1-1), the bonding sites of the six groups bonded to the benzene ring are not particularly limited. In the following formula (2-1), the bonding sites of the eight groups bonded to the naphthalene ring are not particularly limited.

  In said formula (1-1), R1 and R2 represent a C1-C5 alkylene group, respectively. Of the four groups R3, R4, R5 and R6, 2 to 4 groups represent hydrogen. The group which is not hydrogen among R3, R4, R5 and R6 represents a group represented by the following formula (4). All four groups of R3, R4, R5 and R6 may be hydrogen. One or two of the four groups of R3, R4, R5 and R6 is a group represented by the following formula (4), and among the four groups of R3, R4, R5 and R6 The group that is not a group represented by the following formula (4) may be hydrogen.

  In said formula (4), R7 represents a C1-C5 alkylene group.

  In said formula (2-1), R51 and R52 represent a C1-C5 alkylene group, respectively. Of the 6 groups of R53, R54, R55, R56, R57 and R58, 4 to 6 groups represent hydrogen. The group which is not hydrogen among R53, R54, R55, R56, R57 and R58 represents a group represented by the following formula (5). All of the six groups of R53, R54, R55, R56, R57 and R58 may be hydrogen. One or two of the six groups of R53, R54, R55, R56, R57 and R58 are groups represented by the following formula (5), and R53, R54, R55, R56, R57 and R58. Of these, a group that is not a group represented by the following formula (5) may be hydrogen.

  In said formula (5), R59 represents a C1-C5 alkylene group.

  In said formula (3), R101 and R102 represent a C1-C5 alkylene group, respectively. Six to eight groups out of the eight groups of R103, R104, R105, R106, R107, R108, R109 and R110 represent hydrogen. The group which is not hydrogen among R103, R104, R105, R106, R107, R108, R109 and R110 represents a group represented by the following formula (6). All of the eight groups of R103, R104, R105, R106, R107, R108, R109 and R110 may be hydrogen. One or two of the eight groups of R103, R104, R105, R106, R107, R108, R109 and R110 are groups represented by the following formula (6), and R103, R104, R105, R106 , R107, R108, R109 and R110, which is not a group represented by the following formula (6), may be hydrogen.

  In said formula (6), R111 represents a C1-C5 alkylene group.

  In said formula (7), R1 and R2 represent a C1-C5 alkylene group, respectively.

  In said formula (8), R3 and R4 represent a C1-C5 alkylene group, respectively.

  The episulfide compound preferably has a structure represented by the above formulas (1-1) and (2-1), and is an episulfide compound having a structure represented by the following formulas (1) and (2). Is more preferable.

  In the above formula (1), R1 to R6 are the same groups as R1 to R6 in the above formula (1-1).

  In the above formula (2), R51 to R58 are the same groups as R51 to R58 in the above formula (2-1).

  The anisotropic conductive material may include a modified phenoxy resin having a thiirane group in which an epoxy group of the phenoxy resin is converted into a thiirane group as an episulfide compound. Using a sulfurizing agent, the epoxy group of the phenoxy resin can be converted to a thiirane group by a conventionally known method.

  The “phenoxy resin” is generally a resin obtained by reacting, for example, an epihalohydrin and a divalent phenol compound, or a resin obtained by reacting a divalent epoxy compound with a divalent phenol compound. .

  In the above reaction for obtaining a phenoxy resin, by using a compound having a thiirane group obtained by converting the epoxy group of the compound having an epoxy group into a thiirane group instead of the compound having an epoxy group as a raw material of the phenoxy resin, The phenoxy resin which has can be obtained. Furthermore, a phenoxy resin having a thiirane group can also be obtained by preparing a phenoxy resin having an epoxy group and converting the epoxy group of the phenoxy resin having an epoxy group into a thiirane group. In this specification, the resin obtained by these methods is referred to as a modified phenoxy resin having a thiirane group. A resin in which an epoxy group of a phenoxy resin having an epoxy group is converted into a thiirane group is referred to as a modified phenoxy resin having a thiirane group.

  The epoxy compound is not particularly limited. A conventionally well-known epoxy compound can be used as an epoxy compound. As for the said epoxy compound, only 1 type may be used and 2 or more types may be used together.

  Examples of the epoxy compound include phenoxy resin having an epoxy group, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, biphenol type epoxy resin, naphthalene type epoxy resin, fluorene type epoxy resin, phenol aralkyl type epoxy. Examples thereof include a resin, a naphthol aralkyl type epoxy resin, a dicyclopentadiene type epoxy resin, an anthracene type epoxy resin, an epoxy resin having an adamantane skeleton, an epoxy resin having a tricyclodecane skeleton, and an epoxy resin having a triazine nucleus in the skeleton.

  Specific examples of the epoxy compound include, for example, epichlorohydrin and bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol D type epoxy resin and the like, bisphenol type epoxy resin, and epichlorohydrin and phenol novolak or cresol novolak. And epoxy novolac resins derived from Various epoxy compounds having two or more oxirane groups in one molecule such as glycidylamine, glycidyl ester, and alicyclic or heterocyclic may be used.

  Furthermore, as the epoxy compound, for example, a structure in which the thiirane group in the structure represented by the formula (1-1), (2-1), (3), (7) or (8) is replaced with an epoxy group is used. You may use the epoxy compound which has.

  Further, the anisotropic conductive material may be an epoxy compound monomer having a structure represented by the following formula (21), a multimer in which at least two of the epoxy compounds are bonded, or the monomer as an epoxy compound. It may contain a mixture of the body and the multimer.

  In said formula (21), R1 represents a C1-C5 alkylene group, R2 represents a C1-C5 alkylene group, R3 is a hydrogen atom, a C1-C5 alkyl group, or following formula ( 22), R4 represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a structure represented by the following formula (23).

  In said formula (22), R5 represents a C1-C5 alkylene group.

  In said formula (23), R6 represents a C1-C5 alkylene group.

  The epoxy compound having the structure represented by the above formula (21) has an unsaturated double bond and at least two epoxy groups. By using the epoxy compound having the structure represented by the above formula (21), the anisotropic conductive material and the B-stage cured product can be rapidly cured at a further lower temperature.

  The anisotropic conductive material is, as an epoxy compound or an episulfide compound, a monomer of a compound having a structure represented by the following formula (31), a multimer in which at least two of the compounds are bonded, or the monomer And a mixture of the multimers.

  In the above formula (31), R1 represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a structure represented by the following formula (32), R2 represents an alkylene group having 1 to 5 carbon atoms, and R3 represents carbon. X 1 represents an oxygen atom or a sulfur atom, and X 2 represents an oxygen atom or a sulfur atom.

  In said formula (32), R4 represents a C1-C5 alkylene group, X3 represents an oxygen atom or a sulfur atom.

  The anisotropic conductive material may contain an epoxy compound having a heterocyclic ring containing a nitrogen atom as an epoxy compound. The epoxy compound having a heterocyclic ring containing a nitrogen atom is preferably an epoxy compound represented by the following formula (41) or an epoxy compound represented by the following formula (42). By using such a compound, the curing rate of the anisotropic conductive material and the B-stage cured product can be further increased, and the heat resistance of the cured product can be further enhanced.

  In said formula (41), R1-R3 represents a C1-C5 alkylene group, respectively, Z represents an epoxy group or a hydroxymethyl group. R1 to R3 may be the same or different.

  In the above formula (42), R1 to R3 each represent an alkylene group having 1 to 5 carbon atoms, p, q and r each represents an integer of 1 to 5, and R4 to R6 each represent an alkylene having 1 to 5 carbon atoms. Represents a group. R1 to R3 may be the same or different. p, q and r may be the same or different. R4-6 may be the same or different.

  The epoxy compound having a heterocyclic ring containing a nitrogen atom is preferably triglycidyl isocyanurate or trishydroxyethyl isocyanurate triglycidyl ether. By using these compounds, the curing rate of the anisotropic conductive material and the B-stage cured product can be further increased.

  The anisotropic conductive material preferably contains an epoxy compound having an aromatic ring as an epoxy compound. By using an epoxy compound having an aromatic ring, the curing rate of the anisotropic conductive material and the B-stage-shaped cured product can be further increased, and the paste-like anisotropic conductive material can be easily applied. From the viewpoint of further improving the applicability of the anisotropic conductive material, the aromatic ring is preferably a benzene ring, a naphthalene ring or an anthracene ring, and more preferably a benzene ring or a naphthalene ring. A naphthalene ring is preferred because it has a planar structure and can be cured more rapidly. Examples of the epoxy compound having an aromatic ring include resorcinol diglycidyl ether or 1,6-naphthalenediglycidyl ether. Of these, resorcinol diglycidyl ether is particularly preferable. By using resorcinol diglycidyl ether, it is possible to increase the curing speed of the anisotropic conductive material and the B-stage-like cured product and to easily apply the paste-like anisotropic conductive material.

Details of the photocurable compound A3:
(Meth) acrylic acid, an ester compound obtained by reacting (meth) acrylic acid with a compound having a hydroxyl group as photocurable compound A3 having no (meth) acryloyl group and having no epoxy group or thiirane group (Meth) acrylate obtained by reacting an epoxy compound with an epoxy compound (but not having an epoxy group), or urethane (meth) acrylate obtained by reacting a (meth) acrylic acid derivative having a hydroxyl group with an isocyanate, etc. Are preferably used.

  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 photocurable compound A3 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 Examples include (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, and tetradecyl (meth) acrylate.

  From the viewpoint of forming an even better sea-island structure in the B-stage-shaped cured product, the anisotropic conductive material comprises a weight ratio of light and thermosetting compound A1, thermosetting compound A2, and photocurable compound A3. (A1: A2: A3), preferably 0.1-20: 50-94.9: 5-45, more preferably 2-10: 70-88: 10-28.

  When the weight ratio (A1: A2: A3) is within the above range, a B-stage film in which the photocuring of the anisotropic conductive material has progressed appropriately can be obtained, and the obtained B-stage film can be efficiently used. Can be thermally cured.

  The smaller the content of the photocurable compound A3, the smaller the volume of the island portion, and the more the content of light and the thermosetting compound A1, the smaller the island portion tends to become smaller. The size of the portion where no conductive particles are present can be reduced.

[Thermosetting agent]
The anisotropic conductive material preferably contains a thermosetting agent. The thermosetting agent is not particularly limited. The thermosetting agent cures a thermosetting compound or light and thermosetting compound. A conventionally known thermosetting agent can be used as the thermosetting agent. As for this thermosetting agent, only 1 type may be used and 2 or more types may be used together.

  Examples of the thermosetting agent include imidazole curing agents, amine curing agents, phenol curing agents, polythiol curing agents, and acid anhydrides. Especially, since an anisotropic conductive material and a B stage-shaped hardened | cured material can be hardened more rapidly at low temperature, an imidazole hardening | curing agent, a polythiol hardening | curing agent, or an amine hardening | curing agent is preferable. Moreover, since a storage stability can be improved when the said sclerosing | hardenable 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. As for these thermosetting agents, only 1 type may be used and 2 or more types may be used together. In addition, the said thermosetting agent may be coat | covered with polymeric substances, such as a polyurethane resin or a polyester resin.

  The imidazole curing agent is not particularly limited, but 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. .

  Although it does not specifically limit as said amine hardening | curing agent, Hexamethylene diamine, octamethylene diamine, decamethylene diamine, 3,9-bis (3-aminopropyl) 2,4,8,10-tetraspiro [5.5] undecane , Bis (4-aminocyclohexyl) methane, metaphenylenediamine, diaminodiphenylsulfone and the like.

  Among the thermosetting agents, polythiol compounds or acid anhydrides are preferably used. Since the curing speed of the anisotropic conductive material and the B-stage cured product can be further increased, a polythiol compound is more preferably used.

  Among the polythiol compounds, pentaerythritol tetrakis-3-mercaptopropionate is more preferable. By using this polythiol compound, the curing rate of the anisotropic conductive material and the B-stage cured product can be further increased.

  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 100 parts by weight with respect to 100 parts by weight of the thermosetting component (thermosetting compound and light and thermosetting compound) in the curable compound A. 1 part by weight or more, preferably 200 parts by weight or less, more preferably 100 parts by weight or less, and still more preferably 75 parts by weight or less. When the content of the thermosetting agent is not less than the above lower limit, it is easy to sufficiently cure the anisotropic conductive material. When the content of the thermosetting agent is not more than the above upper limit, it is difficult for an excess thermosetting agent that did not participate in curing after curing to remain, and the heat resistance of the cured product is further enhanced.

(Photopolymerization initiator)
The anisotropic conductive material preferably contains a photopolymerization initiator. The photopolymerization initiator is not particularly limited. The photopolymerization initiator polymerizes a photocurable compound or light and a thermosetting compound. As the photopolymerization initiator, a conventionally known photopolymerization initiator can be used. As for this photoinitiator, only 1 type may be used and 2 or more types may be used together.

  Specific examples of the photopolymerization initiator include acetophenone photopolymerization initiator, benzophenone photopolymerization initiator, thioxanthone, ketal photopolymerization initiator, halogenated ketone, acyl phosphinoxide, and acyl phosphonate.

  Specific examples of the acetophenone photopolymerization 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 photopolymerization initiator include benzyl dimethyl ketal.

  The content of the photopolymerization initiator is not particularly limited. The content of the photopolymerization initiator is preferably 0.1 parts by weight or more with respect to 100 parts by weight of the photocurable component (photocurable compound and light and thermosetting compound) in the curable compound A. Preferably it is 0.2 parts by weight or more, more preferably 2 parts by weight or more, preferably 10 parts by weight or less, more preferably 5 parts by weight or less. When the content of the photopolymerization initiator is not less than the above lower limit, it is easy to sufficiently obtain the effect of adding the photopolymerization initiator. When the content of the photopolymerization initiator is not more than the above upper limit, the adhesive force of the cured product obtained by curing the anisotropic conductive material and the B-stage cured product is sufficiently high.

[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 conductive particles whose surfaces are coated with a metal layer, such as organic particles, inorganic particles, organic-inorganic hybrid particles, or metal particles, or metal particles that are substantially composed of only metal. It is done. 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 surface of 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. . When the content of the low melting point metal layer is not less than the 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. Further, the use of conductive particles having at least the outer surface of the low-melting-point metal layer increases the bonding strength between the low-melting-point metal layer and the electrode. Thus, 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, 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: solvent term, it is preferable that it is a meltable 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 metal layer, and the resin particles and the low-melting metal In addition to the low melting point metal layer, it is preferable to have a second conductive layer between the layers (such as solder layers). 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 thickness of the low melting point metal layer is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 1 μm or more, preferably 50 μm or less, more preferably 10 μm or less, still more preferably 5 μm or less, particularly preferably. 3 μm or less. When the thickness of the low melting point metal layer is not less than the above lower limit, the conductivity is sufficiently high. When the thickness of the low melting point metal layer is not more than the above upper limit, the difference in thermal expansion coefficient between the resin particles and the low melting point metal layer becomes small, and the low melting point metal layer is hardly peeled off.

  When the conductive layer is a conductive layer other than the low melting point metal layer, or when the conductive layer has a multilayer structure, the total thickness of the conductive layer is preferably 0.1 μm or more, more preferably 0.5 μm or more, Preferably it is 1 micrometer or more, Preferably it is 50 micrometers or less, More preferably, it is 10 micrometers or less, More preferably, it is 5 micrometers or less, Most preferably, it is 3 micrometers or less.

  The particle diameter of the conductive particles is preferably 100 μm or less, more preferably less than 20 μm, still more preferably 15 μm or less, and particularly preferably 10 μm or less. The particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more.

  Since the size is suitable for the conductive particles in the anisotropic conductive material and the distance between the electrodes can be further reduced, the average particle diameter of the conductive particles is in the range of 1 μm to 100 μm. Is particularly preferred.

  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. Further, when the first conductive layer is present between the resin particles and the solder layer, the ratio of the average particle size B of the resin particles 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 first 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.

Anisotropic conductive materials for FOB and FOF applications:
The anisotropic conductive material is used for connection between a flexible printed circuit board and a glass epoxy board (FOB (Film on Board)), or between a flexible printed circuit board and a flexible printed circuit board (FOF (Film on Film)). Preferably used.

  In FOB and FOF applications, L & S, which is the size of a portion (line) with an electrode and a portion (space) without an electrode, is generally 100 to 500 μm. The average particle diameter of the resin particles used for FOB and FOF applications is preferably 10 to 100 μm. When the average particle diameter of the resin particles is 10 μm or more, the thickness of the anisotropic conductive material disposed between the electrodes and the connection portion is sufficiently increased, and the adhesive force is further increased. When the average particle diameter of the resin particles is 100 μm or less, a short circuit is more unlikely to occur between adjacent electrodes.

Anisotropic conductive materials for flip chip applications:
The anisotropic conductive material is suitably used for flip chip applications.

  For flip chip applications, the land diameter is generally 15-80 μm. The average particle size of the resin particles used for flip chip applications is preferably 1 to 15 μm. When the average particle diameter of the resin particles is 1 μm or more, the thickness of the solder layer disposed on the surface of the resin particles can be sufficiently increased, and the electrodes can be more reliably electrically connected. it can. When the average particle diameter of the resin particles is 10 μm or less, a short circuit is more unlikely to occur between adjacent electrodes.

Anisotropic conductive material for COF:
The anisotropic conductive material is preferably used for connection between a semiconductor chip and a flexible printed board (COF (Chip on Film)).

  In a COF application, L & S, which is a dimension between a portion (line) with an electrode and a portion (space) without an electrode (space), is generally 10 to 50 μm. The average particle diameter of the resin particles used for COF applications is preferably 1 to 10 μm. When the average particle diameter of the resin particles is 1 μm or more, the thickness of the solder layer disposed on the surface of the resin particles can be sufficiently increased, and the electrodes can be more reliably electrically connected. it can. When the average particle diameter of the resin particles is 10 μm or less, a short circuit is more unlikely to occur between adjacent electrodes.

  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 surface of the conductive particles may be insulated with an insulating material, insulating particles, flux, or the like. It is preferable that the insulating material, the insulating particles, the flux, and the like are removed from the connection portion by being softened and flowed by heat at the time of connection. Thereby, the short circuit between electrodes can be suppressed.

  The content of the conductive particles is not particularly limited. The content of the conductive particles in 100% by weight of the anisotropic conductive material is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, preferably 40% by weight or less, more preferably 20% by weight. % Or less, more preferably 10% 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.

  When the anisotropic conductive material is pasty, the viscosity (25 ° C.) of the anisotropic conductive material is preferably in the range of 20,000 to 300,000 mPa · s. If the viscosity is too low, the conductive particles may settle. If the viscosity is too high, the conductive particles may not be sufficiently dispersed. The paste form includes liquid.

[Other ingredients]
The anisotropic conductive material preferably further includes 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 content of the filler is not particularly limited. A preferable lower limit of the filler content is 5 parts by weight, a more preferable lower limit is 15 parts by weight, a preferable upper limit is 70 parts by weight, and a more preferable upper limit is 50 parts by weight with respect to 100 parts by weight of the curable compound A. When the filler content is not less than the above lower limit and not more than the above upper limit, the adhesive force on the surface of the B-stage cured product can be easily controlled within a suitable range. Furthermore, the dispersibility of the filler in the anisotropic conductive material and the B stage-shaped cured product can be enhanced, and the latent thermal expansion of the cured product obtained by curing the anisotropic conductive material and the B stage-shaped cured product can be suppressed.

  The anisotropic conductive material preferably further contains a curing accelerator. By using the curing accelerator, the curing rate of the anisotropic conductive material and the B-stage cured product 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.

  Examples of the imidazole curing accelerator include 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-triazine isocyanuric acid addition Thing etc. are mentioned.

  The content of the curing accelerator is preferably 0.5 parts by weight or more, more preferably 100 parts by weight with respect to 100 parts by weight of the thermosetting component (thermosetting compound and light and thermosetting compound) in the curable compound A. 1 part by weight or more, preferably 6 parts by weight or less, more preferably 4 parts by weight or less. When the content of the curing accelerator is not less than the above lower limit, it is easy to sufficiently cure the anisotropic conductive material and the B-stage cured product. When the content of the curing accelerator is less than or equal to the above upper limit, it is difficult for an excessive curing accelerator that did not participate in curing after curing to remain.

  It is preferable that the anisotropic conductive material further includes a phenolic compound together with an episulfide compound (a compound having a thiirane group). The combined use of the episulfide compound, the thermosetting agent, and the phenolic compound makes it more difficult for the thiirane group to open during storage of the anisotropic conductive material. Further, when an anisotropic conductive material containing conductive particles is disposed between the electrodes and the conductive particles are appropriately compressed, an appropriate impression can be formed on the electrode. Therefore, the connection resistance between the electrodes can be lowered.

  The phenolic compound has a phenolic hydroxyl group in which a hydroxyl group is bonded to a benzene ring. Examples of the phenolic compound include polyphenol, triol, hydroquinone, and tocopherol (vitamin E). As for the said phenolic compound, only 1 type may be used and 2 or more types may be used together.

  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.

  It is preferable that the anisotropic conductive material further includes a storage stabilizer. The anisotropic conductive material preferably contains at least one selected from the group consisting of phosphate ester, phosphite ester and borate ester as the storage stabilizer. It is more preferable that at least one of them is included, and it is even more preferable that a phosphite is included. By using these storage stabilizers, particularly by using phosphites, the storage stability of the episulfide compound can be further enhanced. As for the said storage stabilizer, only 1 type may be used and 2 or more types may be used together.

  Examples of the phosphate ester include diethyl benzyl phosphate. As the phosphite, diphenyl mono (2-ethylhexyl) phosphite, diphenyl monodecyl phosphite or diphenyl mono (tridecyl) phosphite is preferable, and diphenyl monodecyl phosphite and diphenyl mono (tridecyl) phosphite are listed. It is done.

  The anisotropic conductive material includes at least one component selected from the group consisting of ascorbic acid, ascorbic acid derivatives, ascorbic acid salts, isoascorbic acid, isoascorbic acid derivatives, and isoascorbic acid salts. You may go out. By blending these components, the storage stability of the anisotropic conductive material is increased.

  The anisotropic conductive material may further contain an ion scavenger or a silane coupling agent as necessary.

(Details and applications of anisotropic conductive materials)
The anisotropic conductive material according to the present invention is a paste-like or film-like anisotropic conductive material, and is preferably a paste-like anisotropic conductive material. The paste-like anisotropic conductive material is an anisotropic conductive paste. The film-like anisotropic conductive material is an anisotropic conductive film. When the anisotropic conductive material is an anisotropic conductive film, a film that does not include conductive particles may be laminated on the anisotropic conductive film that includes the conductive particles.

  Each of the anisotropic conductive material and the B-stage cured product according to the present invention can be used for bonding various connection target members. The anisotropic conductive material and the B-stage cured product are each suitably used for obtaining a connection structure in which the first and second connection target members are electrically connected.

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

  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 portion 3 is formed by curing an anisotropic conductive material including the conductive particles 5 or a B-stage-shaped cured product obtained by proceeding curing of the anisotropic conductive material.

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

  The connection between the electrodes 2b and 4b is usually performed after the first connection target member 2 and the second connection target member 4 are overlapped with each other via the anisotropic conductive material so that the electrodes 2b and 4b face each other. When the anisotropic conductive material is cured, it is performed by applying pressure. Generally, the conductive particles 5 are compressed by pressurization.

  Specifically, as the connection structure, an electronic component chip such as a semiconductor chip, a capacitor chip or a diode chip is mounted on a circuit board, and the electrode of the electronic component chip is connected to an electrode on the circuit board. Examples include electrically connected structures. As a circuit board, various printed circuit boards, such as various printed circuit boards, such as a flexible printed circuit board, a glass substrate, or a board | substrate with which metal foil was laminated | stacked are mentioned. The first and second connection target members are preferably electronic components or circuit boards. The anisotropic conductive material is preferably an anisotropic conductive material used for connecting an electronic component or a circuit board. The anisotropic conductive material is preferably an anisotropic conductive paste and is an anisotropic conductive material that is applied to the upper surface of the connection target member in a paste state.

  Incidentally, in recent years, the width of a plurality of electrodes provided on a circuit board or the like has been reduced. For example, the width of the plurality of electrodes may be 30 μm or less or about 20 μm. Even if an anisotropic conductive material and a B-stage cured product are used for the connection of such fine electrodes, the island portion where the conductive particles in the B-stage cured product are difficult to contain can be made relatively small. Since the size of the island portion can be less than 20 μm and further 10 μm or less, the conductive particles can be accurately arranged between the upper limit electrodes to be connected. That is, since the size of the portion not including the conductive particles can be reduced, the conductive particles can be accurately arranged between the upper limit electrodes to be connected.

  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 episulfide compound-containing mixture In a 2 L vessel equipped with a stirrer, a cooler and a thermometer, ethanol 250 mL, pure water 250 mL, and potassium thiocyanate 20 g were added to dissolve potassium thiocyanate, One solution was prepared. Thereafter, the temperature in the container was kept in the range of 20 to 25 ° C. Next, 160 g of resorcinol diglycidyl ether was dropped into the first solution at a rate of 5 mL / min while stirring the first solution in the container maintained at 20 to 25 ° C. After dropping, the mixture was further stirred for 30 minutes to obtain an epoxy compound-containing mixed solution.

  Next, a second solution in which 20 g of potassium thiocyanate was dissolved in a solution containing 100 mL of pure water and 100 mL of ethanol was prepared. The obtained second solution was added to the obtained epoxy group-containing mixed solution at a rate of 5 mL / min, and then stirred for 30 minutes. After stirring, a second solution in which 20 g of potassium thiocyanate is dissolved in a solution containing 100 mL of pure water and 100 mL of ethanol is further prepared, and the second solution is further added to the container at a rate of 5 mL / min. And stirred for 30 minutes. Thereafter, the temperature in the container was cooled to 10 ° C., and stirred for 2 hours to be reacted.

  Next, 100 mL of saturated saline was added to the container and stirred for 10 minutes. After stirring, 300 mL of toluene was further added to the container and stirred for 10 minutes. Thereafter, the solution in the container was transferred to a separating funnel and allowed to stand for 2 hours to separate the solution. The lower solution in the separatory funnel was discharged, and the supernatant was taken out. 100 mL of toluene was added to the removed supernatant, stirred, and allowed to stand for 2 hours. Further, 100 mL of toluene was further added, stirred and allowed to stand for 2 hours.

  Next, 50 g of magnesium sulfate was added to the supernatant liquid to which toluene was added and stirred for 5 minutes. After stirring, magnesium sulfate was removed with a filter paper to separate the solution. The remaining solvent was removed by drying the separated solution under reduced pressure at 80 ° C. using a vacuum dryer. In this way, an episulfide compound-containing mixture was obtained.

¹ H-NMR measurement of the obtained episulfide compound-containing mixture was performed using chloroform as a solvent. As a result, the signal in the region of 6.5 to 7.5 ppm indicating the presence of the epoxy group decreased, and the signal appeared in the region of 2.0 to 3.0 ppm indicating the presence of the episulfide group. This confirmed that some epoxy groups of resorcinol diglycidyl ether were converted into episulfide groups. Moreover, from the integral value of the measurement result of ¹ H-NMR, the episulfide compound-containing mixture contains 70% by weight of resorcinol diglycidyl ether and 30% by weight of the episulfide compound having a structure represented by the following formula (1B). It was confirmed.

(2) Preparation of anisotropic conductive paste 1.5 parts by weight of glycidyl methacrylate (“Blenmer GS” manufactured by NOF Corporation, weight average molecular weight 142) corresponding to light and thermosetting compound A1, and thermosetting compound A2 Corresponding 30 parts by weight of the resulting episulfide compound-containing mixture, 5 parts by weight of an amine adduct (“PN-23J” manufactured by Ajinomoto Fine Techno Co.) as a thermosetting agent, and an epoxy acrylate (epoxy) corresponding to the photocurable compound A3 And 5 parts by weight of Daicel Cytec's “EBECRYL 3702” which does not have a group or thiirane group, and 0.1 parts by weight of an acylphosphine oxide compound (“DAROCUR TPO” made by Ciba Japan) as a photopolymerization initiator And 1 part by weight of 2-ethyl-4-methylimidazole as a curing accelerator, and silica as a filler 20 parts by weight (average particle diameter 0.25 μm) and 20 parts by weight of alumina (average particle diameter 0.5 μm) as filler are blended, and conductive particles A having an average particle diameter of 3 μm are added in 100% by weight of the blend. Was added so that the content at 10% by weight was obtained, followed by stirring at 2000 rpm for 5 minutes using a planetary stirrer to obtain a blend.

  The conductive particles A used are conductive particles having a metal layer in which a nickel plating layer is formed on the surface of divinylbenzene resin particles and a gold plating layer is formed on the surface of the nickel plating layer. It is the electroconductive particle whose specific gravity is 3.0.

  The obtained blend was filtered using a nylon filter paper (pore diameter: 10 μm) to obtain an anisotropic conductive paste having a conductive particle content of 10% by weight.

(3) Preparation of connection structure The transparent glass substrate with which the ITO electrode pattern whose L / S is 20 micrometers / 20 micrometers was formed in the upper surface was prepared. Further, a semiconductor chip having a copper electrode pattern with an L / S of 20 μm / 20 μm formed on the lower surface was prepared.

  Moreover, the composite apparatus provided with a dispenser and the ultraviolet irradiation lamp as a light irradiation apparatus connected to this dispenser was prepared.

While moving the composite apparatus, the anisotropic conductive paste obtained was applied to the upper surface of the transparent glass substrate from the syringe of the dispenser so as to have a thickness of 20 μm to form an anisotropic conductive paste layer. Further, while moving the composite device and applying the anisotropic conductive paste, using the ultraviolet irradiation lamp on the anisotropic conductive paste layer, the ultraviolet irradiation of 420 nm is applied so that the light irradiation energy is 50 mW / cm ^2. Then, the anisotropic conductive paste layer was B-staged by photopolymerization. The time T from the time when the anisotropic conductive paste was applied to the transparent glass substrate to the time when the anisotropic conductive paste layer was irradiated with light was 0.5 seconds. .

  Next, the semiconductor chip was stacked on the upper surface of the B-staged anisotropic conductive paste layer (B-stage cured product) so that the electrodes face each other. Then, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer becomes 185 ° C., a pressure heating head is placed on the upper surface of the semiconductor chip, and a pressure of 3 MPa is applied to make the B-staged difference. The isotropic conductive paste layer was completely cured at 185 ° C. to obtain a connection structure.

(Example 2)
In the preparation of the anisotropic conductive paste, glycidyl methacrylate (“Blenmer GS” manufactured by NOF Corporation, weight average molecular weight 142) corresponding to light and thermosetting compound A1 corresponds to light and thermosetting compound A1. An anisotropic conductive paste and a connecting structure were prepared in the same manner as in Example 1 except that allyl glycidyl ether (Yokkaichi Synthesis Co., Ltd., weight average molecular weight 114) was changed.

(Example 3)
In the preparation of the anisotropic conductive paste, glycidyl methacrylate (“Blenmer GS” manufactured by NOF Corporation, weight average molecular weight 142) corresponding to light and thermosetting compound A1 corresponds to light and thermosetting compound A1. An anisotropic conductive paste and a connection structure were prepared in the same manner as in Example 1 except that 4-hydroxybutyl acrylate glycidyl ether (“4HBAGE” manufactured by Nippon Kasei Co., Ltd., weight average molecular weight 200) was used.

Example 4
In the preparation of the anisotropic conductive paste, epoxy acrylate corresponding to the photocurable compound A3 (“EBECRYL3702” manufactured by Daicel-Cytec Co., Ltd.) and tripropylene glycol diacrylate corresponding to the photocurable compound A3 (epoxy group and An anisotropic conductive paste and a connecting structure were produced in the same manner as in Example 1 except that the TGPDA was changed to “TPGDA” manufactured by Daicel-Cytec, which does not have a thiirane group.

(Example 5)
In the preparation of the anisotropic conductive paste, epoxy acrylate corresponding to the photocurable compound A3 (“EBECRYL3702” manufactured by Daicel-Cytec Co., Ltd.) and urethane acrylate (epoxy group and thiirane group corresponding to the photocurable compound A3) were used. An anisotropic conductive paste and a connection structure were produced in the same manner as in Example 1 except that the material was changed to “EBECRYL8405” manufactured by Daicel-Cytec Corporation.

(Example 6)
In the preparation of the anisotropic conductive paste, the episulfide compound-containing mixture corresponding to the thermosetting compound A2 is converted into a naphthalene glycidyl ether (no (meth) acryloyl group) corresponding to the thermosetting compound A2. An anisotropic conductive paste and a connection structure were produced in the same manner as in Example 1 except that the change was made to “HP-4032D”).

(Comparative Example 1)
In the preparation of the anisotropic conductive paste, Example 1 except that glycidyl methacrylate (“Blemmer GS” manufactured by NOF Corporation, weight average molecular weight 142) corresponding to light and thermosetting compound A1 was not blended. Similarly, an anisotropic conductive paste and a connection structure were produced.

(Comparative Example 2)
Anisotropic conductive paste was prepared in the same manner as in Example 1 except that epoxy acrylate corresponding to the photocurable compound A3 (“EBECRYL 3702” manufactured by Daicel-Cytec) was not blended. A conductive paste and a connection structure were produced.

(Evaluation of Examples 1 to 6 and Comparative Examples 1 and 2)
(1) Presence or absence of sea-island structure The anisotropic conductive pastes obtained in Examples 1 to 6 and Comparative Examples 1 and 2 were applied on a transparent glass substrate so as to have a thickness of 20 μm. Thereafter, the anisotropic conductive paste layer is irradiated with an ultraviolet irradiation lamp so that the light irradiation energy is 50 mW / cm ^2, and the anisotropic conductive paste is cured by photopolymerization to obtain a B-stage cured product. Got. A transparent glass substrate was further placed on the upper surface of the B-staged anisotropic conductive paste layer, and the B-stage cured product was thinly stretched by applying pressure from the top so that the thickness became 5 μm.

  Using an optical microscope, the presence or absence of a sea-island structure in the B-stage cured product was observed. Furthermore, the size (maximum diameter) of the island was confirmed. The size of the island was determined according to the following criteria.

[Criteria for determining the size of islands]
○: The size of the island portion is 10 μm or less ○: The size of the island portion exceeds 10 μm and less than 20 μm ×: The size of the island portion is 20 μm or more

(2) Presence / absence of conduction between opposing electrodes The connection resistance between the upper and lower electrodes of the obtained connection structure was measured by a four-terminal method. The average value of the two connection resistances was calculated. Note that the connection resistance can be obtained by measuring the voltage when a constant current is passed from the relationship of voltage = current × resistance. The case where the average value of the connection resistance was 2.0Ω or less was judged as “◯”, and the case where the average value of the connection resistance exceeded 2.0Ω was judged as “X”.

(3) Presence or absence of voids In the connection structure obtained by the above evaluation, whether or not voids are generated in the cured product layer formed by the anisotropic conductive paste layer is visually observed from the lower surface side of the transparent glass substrate. Observed. “○○” when there is no void, “◯” when there is only one small void, “△” when there are two or more small voids, and “×” when there is a large void and there is a problem in use. The results are shown in Table 1 below.

  The results are shown in Table 1 below.

(Examples 7 to 12)
Divinylbenzene resin particles having an average particle diameter of 20 μm (“Micropearl SP-220” manufactured by Sekisui Chemical Co., Ltd.) were subjected to electroless nickel plating to form a base nickel plating layer having a thickness of 0.1 μm on the surface of the resin particles. Next, the resin particles on which the base nickel plating layer was formed were subjected to electrolytic copper plating to form a 1 μm thick copper layer. Further, electrolytic plating was performed using an electrolytic plating solution containing tin and bismuth to form a solder layer having a thickness of 3 μm. In this way, a 1 μm thick copper layer is formed on the surface of the resin particles, and a 3 μm thick solder layer (tin: bismuth = 43 wt%: 57 wt%) is formed on the surface of the copper layer. Conductive particles B were prepared.

  In Example 7, anisotropy was performed in the same manner as in Example 1 except that the conductive particles A were changed to the conductive particles B and the filter paper used for the filtration was changed to nylon filter paper (pore diameter 30 μm). A conductive material was obtained.

  In Example 8, anisotropy was performed in the same manner as in Example 2 except that the conductive particles A were changed to the conductive particles B and that the filter paper used for the filtration was changed to nylon filter paper (pore diameter 30 μm). A conductive material was obtained.

  In Example 9, anisotropy was performed in the same manner as in Example 3 except that the conductive particles A were changed to the conductive particles B and that the filter paper used for the filtration was changed to nylon filter paper (pore diameter 30 μm). A conductive material was obtained.

  In Example 10, anisotropy was performed in the same manner as in Example 4 except that the conductive particles A were changed to the conductive particles B and the filter paper used for filtration was changed to nylon filter paper (pore diameter 30 μm). A conductive material was obtained.

  In Example 11, anisotropy was performed in the same manner as in Example 5 except that the conductive particles A were changed to the conductive particles B and the filter paper used for filtration was changed to nylon filter paper (pore diameter 30 μm). A conductive material was obtained.

  In Example 12, anisotropy was performed in the same manner as in Example 6 except that the conductive particles A were changed to the conductive particles B and that the filter paper used for the filtration was changed to nylon filter paper (pore diameter 30 μm). A conductive material was obtained.

(Evaluation of Examples 7-12)
The evaluation items of Examples 1 to 6 and Comparative Examples 1 and 2 were evaluated.

  The results are shown in Table 2 below.

DESCRIPTION OF SYMBOLS 1 ... Connection structure 2 ... 1st connection object member 2a ... Upper surface 2b ... Electrode 3 ... Connection part 4 ... 2nd connection object member 4a ... Lower surface 4b ... Electrode 5 ... Conductive particle

Claims (8)

An anisotropic conductive material containing at least three curable compounds and conductive particles;
The curable compound is a light and thermosetting compound having an epoxy group or thiirane group and a (meth) acryloyl group, and a thermosetting material having an epoxy group or thiirane group and no (meth) acryloyl group. A compound, and a photocurable compound having no epoxy group and thiirane group and having a (meth) acryloyl group,
The weight average molecular weight of the light and thermosetting compound having the epoxy group or thiirane group and the (meth) acryloyl group is less than 100,000,
An anisotropic conductive material having a sea-island structure when the B-stage-shaped cured product is obtained by advancing curing of the anisotropic conductive material.   The anisotropic conductive material according to claim 1, further comprising a thermosetting agent and a photopolymerization initiator. A B-stage-shaped cured product obtained by irradiating the anisotropic conductive material with light and causing the anisotropic conductive material to cure,
The anisotropic conductive material contains at least three curable compounds and conductive particles,
The curable compound is a light and thermosetting compound having an epoxy group or thiirane group and a (meth) acryloyl group, and a thermosetting material having an epoxy group or thiirane group and no (meth) acryloyl group. A compound, and a photocurable compound having no epoxy group and thiirane group and having a (meth) acryloyl group,
The weight average molecular weight of the light and thermosetting compound having the epoxy group or thiirane group and the (meth) acryloyl group is less than 100,000,
B-stage cured product having a sea-island structure.   The B-stage cured product according to claim 3, wherein the anisotropic conductive material further contains a thermosetting agent and a photopolymerization initiator. Irradiating the anisotropic conductive material with light, and proceeding with the curing of the anisotropic conductive material to obtain a B-stage cured product,
The anisotropic conductive material contains at least three kinds of curable compounds and conductive particles, and the curable compound has an epoxy group or thiirane group and a (meth) acryloyl group. A compound, a thermosetting compound having an epoxy group or thiirane group and having no (meth) acryloyl group, and a photocurable compound having no epoxy group and thiirane group and having a (meth) acryloyl group Including
The weight average molecular weight of the light and thermosetting compound having the epoxy group or thiirane group and the (meth) acryloyl group is less than 100,000,
A method for producing a B-stage cured product, which obtains a B-stage cured product having a sea-island structure. The method for producing a B-stage cured product according to claim 5, wherein the anisotropic conductive material further contains a thermosetting agent and a photopolymerization initiator. A first connection target member, a second connection target member, and a connection part that electrically connects the first and second connection target members;
A connection structure in which the connection portion is formed by curing the anisotropic conductive material according to claim 1. 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 B-stage-shaped hardened | cured material of Claim 3 or 4.

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