JP5922544B2 - Anisotropic conductive material and connection structure - Google Patents

Description

  The present invention relates to an anisotropic conductive material including a plurality of conductive particles, for example, for 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 for the present invention, and a connection structure using the anisotropic conductive material.

  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.

  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.

  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. Accordingly, the anisotropic conductive material is cured, and the electrodes are electrically connected through the conductive particles to obtain a connection structure.

  As an example of the anisotropic conductive material, the following Patent Document 1 includes (A) an alicyclic epoxy compound, (B) a cation generator, and (C1) a cationic polymerizable property than the alicyclic epoxy compound. An anisotropic conductive material including a low second cationic polymerizable compound and conductive particles is disclosed. In patent document 1, as said (B) cation generating agent, a phosphate and a borate are mentioned.

JP 2011-111557 A

  A conventional anisotropic conductive material as described in Patent Document 1 including an epoxy compound and a cation generator which is a compound that generates an acid by heating can be cured at a relatively low temperature. However, an anisotropic conductive material including an epoxy compound and a compound that generates an acid upon heating has a problem that storage stability is low.

  Furthermore, when the above connection structure is obtained using a conventional anisotropic conductive material containing an epoxy compound and a compound that generates an acid upon heating, there is a problem that the insulation reliability of the resulting connection structure is lowered. . In particular, the insulation reliability of the connection structure at high temperature and high humidity tends to be low.

  An object of the present invention is to provide an anisotropic conductive material that can be cured at a low temperature, has excellent storage stability, and can obtain a connection structure with high insulation reliability, and an anisotropic conductive material It is to provide a connection structure used.

  According to a wide aspect of the present invention, the epoxy compound, the conductive particles, the first compound represented by the following formula (1), and the compound represented by the following formula (1) are different from each other by heating. An anisotropic conductive material comprising a second compound that generates an acid is provided.

  In the above formula (1), R1 to R5 each represent a hydrogen atom, an alkyl group, an acetyl group, an alkoxycarbonyl group, a benzoyl group or a benzyloxycarbonyl group, and R6 and R7 each represent an alkyl group, a benzyl group, A methylbenzyl group, an m-methylbenzyl group, a p-methylbenzyl group or a naphthylmethyl group is represented, and X1 represents a halogen atom or an alkyl sulfuric acid.

  In a specific aspect of the anisotropic conductive material according to the present invention, the first compound is a compound represented by the following formula (1-1).

  In the above formula (1-1), R6 and R7 each represents an alkyl group, a benzyl group, an o-methylbenzyl group, an m-methylbenzyl group, a p-methylbenzyl group or a naphthylmethyl group, and X1 represents a halogen atom. Or represents alkyl sulfate.

  In a specific aspect of the anisotropic conductive material according to the present invention, the first compound is a compound represented by the following formula (1A).

  X1 in the above formula (1A) represents a halogen atom or an alkyl sulfuric acid.

  In another specific aspect of the anisotropic conductive material according to the present invention, X1 in the first compound is methylsulfuric acid.

  In still another specific aspect of the anisotropic conductive material according to the present invention, the second compound is a compound represented by the following formula (2).

  In the above formula (2), R11 to R15 each represent a hydrogen atom, an alkyl group, an acetyl group, an alkoxycarbonyl group, a benzoyl group or a benzyloxycarbonyl group, and R16 and R17 each represent an alkyl group, a benzyl group, A methylbenzyl group, m-methylbenzyl group, p-methylbenzyl group or naphthylmethyl group is represented, and X11 represents antimony hexafluoride or tetra (pentafluorophenyl) boron.

  In a specific aspect of the anisotropic conductive material according to the present invention, the second compound is a compound represented by the following formula (2-1).

  In the above formula (2-1), R16 and R17 each represents an alkyl group, a benzyl group, an o-methylbenzyl group, an m-methylbenzyl group, a p-methylbenzyl group, or a naphthylmethyl group, and X11 represents a hexafluoro group. Represents antimony fluoride or tetra (pentafluorophenyl) boron.

  In a specific aspect of the anisotropic conductive material according to the present invention, the second compound is a compound represented by the following formula (2A).

  In the above formula (2A), X11 represents antimony hexafluoride or tetra (pentafluorophenyl) boron.

  The thermal decomposition temperature of the compound in which the anion moiety in the first compound is converted to the anion moiety in the second compound is preferably 150 ° C. or higher. In the anisotropic conductive material according to the present invention, the content of the first compound is preferably 0.5 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the second compound. In the anisotropic conductive material according to the present invention, the total content of the first compound and the second compound is preferably 300 parts by weight or less with respect to 100 parts by weight of the conductive particles.

  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 of the above-described anisotropic conductive material.

  The anisotropic conductive material according to the present invention is different from the epoxy compound, the conductive particles, the first compound represented by the formula (1), and the compound represented by the formula (1) by heating. Since it contains the 2nd compound which generate | occur | produces an acid, it can harden | cure at low temperature and is excellent in storage stability. Furthermore, when the above connection structure is obtained using the anisotropic conductive material according to the present invention, the insulation reliability of the obtained connection structure can be increased.

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.

  Details of the present invention will be described below.

  The anisotropic conductive material according to the present invention is different from the epoxy compound, the conductive particles, the first compound represented by the formula (1), and the compound represented by the formula (1) by heating. And a second compound that generates an acid.

  Since the anisotropic conductive material according to the present invention has the above-described composition, the epoxy compound is particularly thermally cured by the second compound that generates an acid by heating, and thus can be cured at a low temperature.

  Furthermore, since the anisotropic conductive material according to the present invention has the above composition, since the first compound represented by the formula (1) is used together with the second compound that generates an acid by heating, Storage stability is sufficiently high.

  Furthermore, by adopting the above composition, the insulation reliability of the connection structure using the anisotropic conductive material according to the present invention can be enhanced. In particular, when the upper and lower electrodes to be connected in the connection structure are connected by the conductive particles contained in the anisotropic conductive material, the insulation reliability between the laterally adjacent electrodes that should not be connected Can increase the sex. Further, high insulation reliability can be sufficiently ensured even when the connection structure is exposed to high temperature and high humidity. In the anisotropic conductive material according to the present invention, the occurrence of migration of the electrodes and conductive particles is suppressed, and as a result, the insulation reliability is increased.

  Hereinafter, each component contained in the anisotropic conductive material according to the present invention and each component preferably contained will be described in detail.

(Epoxy compound)
The epoxy compound contained in the anisotropic conductive material according to the present invention is not particularly limited. A conventionally well-known epoxy compound can be used as this epoxy compound. The epoxy compound refers to an organic compound having at least one epoxy group. 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 bisphenol A type epoxy compound, bisphenol F type epoxy compound, bisphenol S type epoxy compound, phenol novolac type epoxy compound, biphenyl novolac type epoxy compound, biphenol type epoxy compound, resorcin type epoxy compound, naphthalene type epoxy compound. Fluorene type epoxy compound, phenol aralkyl type epoxy compound, naphthol aralkyl type epoxy compound, dicyclopentadiene type epoxy compound, anthracene type epoxy compound, epoxy compound having adamantane skeleton, epoxy compound having tricyclodecane skeleton, and triazine nucleus Examples thereof include an epoxy compound having a skeleton.

  The epoxy compound 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.

(First compound represented by formula (1))
The anisotropic conductive material according to the present invention includes a first compound represented by the following formula (1). The first compound greatly contributes to the improvement of the storage stability of the anisotropic conductive material. As for the said 1st compound, only 1 type may be used and 2 or more types may be used together.

  In the above formula (1), R1 to R5 each represent a hydrogen atom, an alkyl group, an acetyl group, an alkoxycarbonyl group, a benzoyl group or a benzyloxycarbonyl group, and R6 and R7 each represent an alkyl group, a benzyl group, A methylbenzyl group, an m-methylbenzyl group, a p-methylbenzyl group or a naphthylmethyl group is represented, and X1 represents a halogen atom or an alkyl sulfuric acid.

  From the viewpoint of further enhancing the storage stability of the anisotropic conductive material, R1 to R5 in the above formula (1) each represents a hydrogen atom, and R6 and R7 are each an alkyl group, a benzyl group, and о-methylbenzyl. Represents a group, m-methylbenzyl group, p-methylbenzyl group or naphthylmethyl group, and X1 preferably represents a halogen atom or alkylsulfuric acid. That is, the first compound is preferably a compound represented by the following formula (1-1).

  In the above formula (1-1), R6 and R7 each represents an alkyl group, a benzyl group, an o-methylbenzyl group, an m-methylbenzyl group, a p-methylbenzyl group or a naphthylmethyl group, and X1 represents a halogen atom. Or represents alkyl sulfate.

  In the above formula (1), R1 to R5 each represents a hydrogen atom, an alkyl group, an acetyl group, an alkoxycarbonyl group, a benzoyl group or a benzyloxycarbonyl group, R6 and R7 each represent a methyl group, and X1 represents a halogen atom A first compound representing an atom or an alkyl sulfuric acid may be used. Moreover, from the viewpoint of further enhancing the storage stability of the anisotropic conductive material, it is preferable that R1 to R5 in the above formula (1) each represent a hydrogen atom, and R6 and R7 each represent a methyl group. That is, the first compound is preferably a compound represented by the following formula (1A).

  X1 in the above formula (1A) represents a halogen atom or an alkyl sulfuric acid.

From the viewpoint of further enhancing the storage stability of the anisotropic conductive material, X1 in the first compound is preferably alkyl sulfuric acid. Alkyl sulfates is represented by RSO _4. Thus, if X1 is an alkyl sulfate, X1 ^- it is RSO ₄ ^- represented by. The carbon number of the alkyl group in the alkyl sulfuric acid is preferably 5 or less, more preferably 2 or less, and particularly preferably 1.

From the viewpoint of further improving the storage stability of the anisotropic conductive material, the alkyl sulfuric acid is preferably methyl sulfuric acid or ethyl sulfuric acid, and more preferably methyl sulfuric acid. Methyl sulfuric acid is represented by CH ₃ SO ₄ . Thus, if X1 is methyl sulfate, X1 ^- is _CH 3 SO ₄ ^- represented by.

  From the viewpoint of further enhancing the storage stability of the anisotropic conductive material, the first compound is preferably a compound represented by the following formula (1X), and represented by the following formula (1X-1). More preferably, it is a compound represented by the following formula (1AX).

  In the above formula (1X), R1 to R5 each represent a hydrogen atom, an alkyl group, an acetyl group, an alkoxycarbonyl group, a benzoyl group, or a benzyloxycarbonyl group, and R6 and R7 each represent an alkyl group, a benzyl group, Represents a methylbenzyl group, m-methylbenzyl group, p-methylbenzyl group or naphthylmethyl group.

  In the above formula (1X-1), R6 and R7 each represents an alkyl group, a benzyl group, an o-methylbenzyl group, an m-methylbenzyl group, a p-methylbenzyl group, or a naphthylmethyl group.

  The content of the first compound is preferably 0.01 parts by weight or more, more preferably 0.1 parts by weight or more, still more preferably 0.5 parts by weight or more with respect to 100 parts by weight of the second compound. The amount is preferably 100 parts by weight or less, more preferably 50 parts by weight or less, and still more preferably 10 parts by weight or less. When the content of the first compound is not less than the above lower limit, the storage stability of the anisotropic conductive material is further enhanced. When the content of the first compound is not more than the above upper limit, the first compound is not excessive in order to increase the storage stability of the anisotropic conductive material, and the low temperature curability of the anisotropic conductive material is further reduced. Even better.

  From the viewpoint of effectively increasing the storage stability of the anisotropic conductive material, the content of the first compound is 0.5 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the second compound. It is particularly preferred that

(Second compound that generates acid by heating)
The second compound contained in the anisotropic conductive material according to the present invention generates an acid by heating. The second compound is different from the compound represented by the formula (1). The second compound does not correspond to the compound represented by the above formula (1). Therefore, the second compound does not correspond to the first compound. As for the said 2nd compound, only 1 type may be used and 2 or more types may be used together.

  From the viewpoint of making the anisotropic conductive material curable at a lower temperature and further enhancing the storage stability of the anisotropic conductive material and the insulation reliability of the connection structure, the second compound is represented by the following formula ( It is preferable that it is a compound represented by 2).

In the above formula (2), R11 to R15 each represent a hydrogen atom, an alkyl group, an acetyl group, an alkoxycarbonyl group, a benzoyl group or a benzyloxycarbonyl group, and R16 and R17 each represent an alkyl group, a benzyl group, A methylbenzyl group, m-methylbenzyl group, p-methylbenzyl group or naphthylmethyl group is represented, and X11 represents antimony hexafluoride or tetra (pentafluorophenyl) boron. Antimony hexafluoride is represented by SbF _6. Therefore, when the X11 is hexafluoroantimonate, X11 ^- it is SbF ₆ ^- represented by. Tetra (pentafluorophenyl) boron is represented by B (C ₆ F ₅ ) ₄ . Therefore, when the X11 is tetra (pentafluorophenyl) boron, X11 ^- it is _{B (C 6 F 5) 4} - is represented by, in particular represented by the following formula (Xa).

  From the viewpoint of making the anisotropic conductive material curable at a lower temperature and further enhancing the storage stability of the anisotropic conductive material and the insulation reliability of the connection structure, the second compound is represented by the formula ( In 2), R11 to R15 each represent a hydrogen atom, R16 and R17 each represent an alkyl group, a benzyl group, an о-methylbenzyl group, an m-methylbenzyl group, a p-methylbenzyl group, or a naphthylmethyl group, X11 preferably represents antimony hexafluoride or tetra (pentafluorophenyl) boron. That is, the second compound is preferably a compound represented by the following formula (2-1).

  In the above formula (2-1), R16 and R17 each represents an alkyl group, a benzyl group, an o-methylbenzyl group, an m-methylbenzyl group, a p-methylbenzyl group, or a naphthylmethyl group, and X11 represents a hexafluoro group. Represents antimony fluoride or tetra (pentafluorophenyl) boron.

  In the above formula (2), R11 to R15 each represent a hydrogen atom, an alkyl group, an acetyl group, an alkoxycarbonyl group, a benzoyl group or a benzyloxycarbonyl group, R16 represents a naphthylmethyl group, and R17 represents a methyl group. X11 may be a second compound representing antimony hexafluoride or tetra (pentafluorophenyl) boron. From the viewpoint of making the anisotropic conductive material curable at a lower temperature and further enhancing the storage stability of the anisotropic conductive material and the insulation reliability of the connection structure, the second compound is: It is preferable that it is a compound represented by Formula (2A).

  In the above formula (2A), X11 represents antimony hexafluoride or tetra (pentafluorophenyl) boron.

  The thermal decomposition temperature of the compound in which the anion moiety in the first compound is converted to the anion moiety in the second compound (hereinafter sometimes referred to as compound C) is preferably 130 ° C. or higher, more preferably 150. ℃ or higher, preferably 250 ℃ or lower, more preferably 220 ℃ or lower. When the compound C thermal decomposition temperature is not less than the above lower limit, the thermosetting of the anisotropic conductive material becomes good, and the storage stability of the anisotropic conductive material is further enhanced. When the thermal decomposition temperature of the compound C is not more than the above upper limit, the anisotropic conductive material can be cured at a lower temperature. The thermal decomposition temperature of the compound C is more preferably 150 ° C. or higher.

  The first compound represented by the above formula (1) or the above formula (1X) and the second compound represented by the above formula (2), the above formula (2-1) or the above formula (2A) When is used, the compound C is represented by the following formula (11).

  In the above formula (11), R1 to R5 each represent a hydrogen atom, an alkyl group, an acetyl group, an alkoxycarbonyl group, a benzoyl group, or a benzyloxycarbonyl group, and R6 and R7 each represent an alkyl group, a benzyl group, A methylbenzyl group, m-methylbenzyl group, p-methylbenzyl group or naphthylmethyl group is represented, and X11 represents antimony hexafluoride or tetra (pentafluorophenyl) boron.

  The first compound represented by the formula (1-1) or the formula (1X-1) and the formula (2), the formula (2-1) or the formula (2A) When compound 2 is used, the compound C is represented by the following formula (11-1).

  In the above formula (11-1), R6 and R7 each represents an alkyl group, a benzyl group, an o-methylbenzyl group, an m-methylbenzyl group, a p-methylbenzyl group, or a naphthylmethyl group, and X11 represents a hexafluoro group. Represents antimony fluoride or tetra (pentafluorophenyl) boron.

  A first compound represented by the above formula (1A) or the above formula (1AX) and a second compound represented by the above formula (2), the above formula (2-1) or the above formula (2A). When used, the compound C is represented by the following formula (11X).

  In the above formula (11X), X11 represents antimony hexafluoride or tetra (pentafluorophenyl) boron.

  The total content of the first compound and the second compound is preferably 10 parts by weight or more, more preferably 50 parts by weight or more, and still more preferably 100 parts by weight with respect to 100 parts by weight of the conductive particles. Part or more, preferably 1000 parts by weight or less, more preferably 500 parts by weight or less, and still more preferably 300 parts by weight or less. When the total content of the first and second compounds is not less than the above lower limit, the low-temperature curability of the anisotropic conductive material is further improved. When the total content of the first and second compounds is not more than the above upper limit, the insulation reliability of the connection structure is further improved.

  From the viewpoint of effectively increasing the insulation reliability of the connection structure, the total content of the first and second compounds is particularly 300 parts by weight or less with respect to 100 parts by weight of the conductive particles. preferable.

(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. The surface of the conductive layer of the conductive particles may be covered with insulating particles. In these cases, the insulating layer or insulating particles between the conductive layer and the electrode are excluded when the connection target member is connected. The conductive particles include, for example, organic particles, inorganic particles excluding metal particles, organic-inorganic hybrid particles or conductive particles whose surfaces are covered with a metal layer (conductive layer), and substantially only metal. Examples thereof include metal particles. 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, and a metal layer containing tin.

  From the viewpoint of further improving the conduction reliability between the electrodes, the conductive particles preferably include resin particles and a conductive layer disposed on the surface of the resin particles. The conductive particles may be conductive particles in which at least the outer surface layer of the conductive layer is 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.

  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, particularly preferably 10 μm or less, and most preferably 5 μm. Is less than.

  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 content of the conductive particles with respect to 100 parts by weight of the epoxy compound is preferably 0.1 parts by weight or more, more preferably 0.5 parts by weight or more, further preferably 1 part by weight or more, and particularly preferably 2 parts by weight. Part by weight or more, preferably 40 parts by weight or less, more preferably 30 parts by weight or less, and still more preferably 20 parts 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, the thermal expansion coefficient of the cured product of the anisotropic conductive material can be suppressed. Specific examples of the filler include silica, aluminum nitride, alumina, glass, boron nitride, silicon nitride, silicone, carbon, graphite, graphene, and talc. As for the said filler, only 1 type may be used and 2 or more types may be used together. When a filler having a high thermal conductivity is used, the main curing time is shortened.

  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.

(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.

  The viscosity of the anisotropic conductive paste at 25 ° C. is preferably 20 Pa · s or more, more preferably 50 Pa · s or more, preferably 700 Pa · s or less, more preferably 500 Pa · s or less. When the viscosity is equal to or higher than the lower limit, sedimentation of conductive particles in the anisotropic conductive paste can be suppressed. When the viscosity is equal to or lower than the upper limit, the dispersibility of the conductive particles is further increased. If the viscosity of the anisotropic conductive paste before application is within the above range, after the anisotropic conductive paste is applied on the first connection target member, the flow of the anisotropic conductive paste before curing is more It becomes more difficult to generate, and voids are further less likely to be generated.

  The anisotropic conductive material which concerns on this invention can be used in order to adhere | attach various connection object members. The anisotropic conductive material is 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 portion that electrically connects the first and second connection target members 2 and 4. 3. The connection portion 3 is a cured product layer and is formed by curing an anisotropic conductive material including the 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. Therefore, the first and second connection target members 2 and 4 are electrically connected by the conductive particles 5.

  The connection between the first and second electrodes 2b and 4b is usually performed by connecting the first connection target member 2 and the second connection target member 4 with an anisotropic conductive material between the first and second electrodes 2b. , 4b are overlapped so as to face each other, and then the anisotropic conductive material is cured by applying pressure. Generally, the conductive particles 5 are compressed by pressurization.

  The said 1st, 2nd connection object member is not specifically limited. Specific examples of the first and second connection target members include electronic components such as semiconductor chips, capacitors, and diodes, and electronic components such as circuit boards such as printed boards, flexible printed boards, and glass boards. It is done. The anisotropic conductive material is preferably an anisotropic conductive material used for connecting electronic components. 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.

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

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

  In the examples, comparative examples, and reference examples, the following materials were used.

(Epoxy compound)
Epoxy compound 1 (DIC Corporation "EXA4850-150")
Epoxy compound 2 (“EP-4000S” manufactured by ADEKA)

(First compound)
First compound 1 (compound represented by the above formula (1AX))
First compound 2 (compound represented by the above formula (1), wherein R1 to R5 are each a hydrogen atom, R6 is a naphthylmethyl group, R7 is a methyl group, and X1 is methylsulfuric acid)
First compound 3 (compound represented by the above formula (1), wherein R1 to R5 are each a hydrogen atom, R6 and R7 are methyl groups, and X1 is a chlorine atom)

(Second compound)
Second compound 1 (compound represented by the above formula (2A), wherein X11 is tetra (pentafluorophenyl) borane)
Second compound 2 (compound represented by the above formula (2A), wherein X11 is antimony hexafluoride)
Second compound 3 (compound represented by the above formula (2), wherein R11 to R15 are each a hydrogen atom, R16 and R17 are benzylmethyl groups, and X11 is tetra (pentafluorophenyl) boron)

(Conductive particles)
Conductive particles 1 (conductive particles having an average particle diameter of 10 μm, 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)
Conductive particles 2 (conductive particles having an average particle diameter of 10 μm and a metal layer in which a nickel plating layer is formed on the surface of divinylbenzene resin particles)

(Examples 1 to 18 and Comparative Examples 1 and 2)
The components shown in Table 1 below were blended in the blending amounts shown in Table 1 below to obtain anisotropic conductive paste.

(Evaluation)
(1) Thermal decomposition temperature The thermal decomposition temperature of the compound C in which the anion part in the said 1st compound was converted into the anion part in the said 2nd compound was evaluated. The thermal decomposition temperature was measured using a DSC apparatus (“Q100” manufactured by TA Instruments). The thermal decomposition temperature was determined according to the following criteria.

[Criteria for thermal decomposition temperature]
○: Thermal decomposition temperature is 150 ° C or higher and 250 ° C or lower ×: Thermal decomposition temperature is lower than 150 ° C

(2) Low-temperature curability and conductivity evaluation A glass epoxy substrate (FR-4 substrate) having a gold electrode pattern with an L / S of 200 μm / 200 μm on the upper surface was prepared. A flexible substrate having a gold electrode pattern with L / S of 200 μm / 200 μm on the upper surface was prepared.

  An anisotropic conductive material layer was formed on the top surface of the glass epoxy substrate by coating the anisotropic conductive material immediately after fabrication so as to have a thickness of 30 μm. Next, the flexible substrate was laminated on the upper surface of the anisotropic conductive material layer so that the electrodes face each other. Then, while adjusting the temperature of the head so that the temperature of the anisotropic conductive material layer becomes 170 ° C. or 190 ° C., a pressure heating head is placed on the upper surface of the flexible substrate and a pressure of 2.0 MPa is applied to the anisotropic The conductive material layer was cured at 170 ° C. or 190 ° C. for 10 seconds to obtain a connection structure.

  About the obtained connection structure, low-temperature curability was determined on the following reference | standard from the hardening state of the anisotropic electrically conductive paste, and the resistance value in a connection structure.

[Criteria for low-temperature curability]
○: The paste is cured at both 170 ° C. and 190 ° C., and the resistance value is 2.0Ω or less. Δ: The paste is cured only at 190 ° C., and the resistance value is 2.0Ω or less. The paste is not cured at both of 190 ° C, and the boards are not connected.

(3) Storage stability Using a viscometer (“TV-22” manufactured by Toki Sangyo Co., Ltd.), the viscosity η1 of the anisotropic conductive material immediately after production was measured under the conditions of 25 ° C. and 5 rpm. After producing the anisotropic conductive material, it was stored at 25 ° C. for 72 hours. Under the same conditions as the viscosity η1, the viscosity η2 of the anisotropic conductive material after storage was measured. Storage stability was determined according to the following criteria.

[Criteria for storage stability]
◯: Viscosity η2 is 120% or less of viscosity η1 ○: Viscosity η2 exceeds 120% of viscosity η1, 130% or less Δ: Viscosity η2 exceeds 130% of viscosity η1, 140% or less ×: Viscosity η2 is viscosity Over 140% of η1

(4) Insulation reliability A glass epoxy substrate (FR-4 substrate) having a comb-shaped copper electrode pattern with an L / S of 80 μm / 80 μm on the upper surface was prepared.

  An anisotropic conductive material layer was formed on the top surface of the glass epoxy substrate by coating the anisotropic conductive material immediately after fabrication so as to have a thickness of 30 μm. Next, while laminating the glass and adjusting the temperature of the head so that the temperature of the anisotropic conductive material layer is 190 ° C., a pressure heating head is placed on the upper surface of the glass and a pressure of 2.0 MPa is applied. The anisotropic conductive material layer was cured at 190 ° C. for 10 seconds to obtain a connection structure.

The connection structure thus obtained was exposed for 500 hours in an atmosphere of 85 ° C. and 85% RH with a voltage of 20 V applied between the measurement terminals insulated from each other (insulation reliability test). During this time, the change in resistance value between the measurement terminals was measured. A case where the resistance value was 10 ⁷ Ω or less was judged as an insulation failure. Insulation reliability was judged according to the following criteria.

[Criteria for insulation reliability]
○: Among 10 connection structures, there is no connection structure that has a resistance value of less than 10 ⁷ Ω during exposure for 500 hours. Δ: Of 10 connection structures, the resistance value is 10 during exposure for 500 hours. Although there is a connection structure that is less than ⁷ Ω, there is no connection structure that is less than 10 ⁵ Ω. X: Of 10 connection structures, a connection structure whose resistance value is less than 10 ⁵ Ω during 500 hours exposure There is more than one body

  The results are shown in Table 1 below. In Table 1 below, “−” indicates that evaluation is not performed.

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

Claims (10)

An epoxy compound,
Conductive particles;
A first compound represented by the following formula ( 1-1 );
An anisotropic conductive material comprising a second compound that is different from the compound represented by the following formula (1) and generates an acid by heating.

In the formula (1), R1 to R5 each represent a hydrogen atom, an alkyl group, an acetyl group, an alkoxycarbonyl group, a benzoyl group, or a benzyloxycarbonyl group, and R6 and R7 each represent an alkyl group, a benzyl group, A methylbenzyl group, an m-methylbenzyl group, a p-methylbenzyl group or a naphthylmethyl group is represented, and X1 represents a halogen atom or an alkyl sulfuric acid.

In the formula (1-1), R6 and R7 each represents an alkyl group, a benzyl group, an o-methylbenzyl group, an m-methylbenzyl group, a p-methylbenzyl group or a naphthylmethyl group, and X1 represents a halogen atom. Or represents alkyl sulfate. The anisotropic conductive material according to claim 1 , wherein the first compound is a compound represented by the following formula (1A).

X1 in the formula (1A) represents a halogen atom or an alkyl sulfuric acid. The anisotropic conductive material according to claim 1 or 2 , wherein X1 in the first compound is methylsulfuric acid. The anisotropic conductive material according to any one of claims 1 to 3 , wherein the second compound is a compound represented by the following formula (2).

In the formula (2), R11 to R15 each represent a hydrogen atom, an alkyl group, an acetyl group, an alkoxycarbonyl group, a benzoyl group or a benzyloxycarbonyl group, and R16 and R17 each represent an alkyl group, a benzyl group, A methylbenzyl group, m-methylbenzyl group, p-methylbenzyl group or naphthylmethyl group is represented, and X11 represents antimony hexafluoride or tetra (pentafluorophenyl) boron. The anisotropic conductive material according to claim 4 , wherein the second compound is a compound represented by the following formula (2-1).

In the formula (2-1), R16 and R17 each represents an alkyl group, a benzyl group, an o-methylbenzyl group, an m-methylbenzyl group, a p-methylbenzyl group, or a naphthylmethyl group, and X11 represents a hexafluoro group. Represents antimony fluoride or tetra (pentafluorophenyl) boron. The anisotropic conductive material according to claim 5 , wherein the second compound is a compound represented by the following formula (2A).

In the formula (2A), X11 represents antimony hexafluoride or tetra (pentafluorophenyl) boron. The anisotropic conduction according to any one of claims 1 to 6 , wherein the thermal decomposition temperature of the compound in which the anion moiety in the first compound is converted to the anion moiety in the second compound is 150 ° C or higher. material. The anisotropy according to any one of claims 1 to 7 , wherein a content of the first compound is 0.5 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the second compound. Conductive material. The difference according to any one of claims 1 to 8 , wherein the total content of the first compound and the second compound is 300 parts by weight or less with respect to 100 parts by weight of the conductive particles. Isotropic conductive material. A first connection target member;
A second connection target member;
A connecting portion electrically connecting the first and second connection target members;
The connecting portion is formed by an anisotropic conductive material according to any one of claims 1 to 9 connected structure.

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