JP6102105B2 - Film-like circuit connection material and circuit connection structure - Google Patents

Description

  The present invention relates to a film-like circuit connection material and a circuit connection structure.

  With the increase in the size of displays in applications such as televisions, the number of display elements and the number of semiconductor elements have increased, resulting in an increase in the size of circuit boards used. When connecting the first circuit board and the second circuit board via a cured product of a film-like circuit connection material cured by heating and / or ultraviolet irradiation, the first circuit board and the second circuit board, In addition, each of the film-like circuit connecting materials receives a thermal history, but stress tends to be generated due to a difference in coefficient of thermal expansion of each member. Due to the influence of this stress, the joint between the first circuit board or the second circuit board and the film-like circuit connecting material is likely to be peeled off, which may cause a connection failure between the circuit boards and cause a lighting failure of the display panel. There is.

  In addition, as an adhesive used for film-like circuit connection materials, epoxy resin adhesives are generally excellent in reliability such as water resistance and heat resistance, so they can be used in various applications such as electrical, electronic, architectural, automotive, and aircraft. It is used a lot. On the other hand, in recent years, there has been a demand for low-temperature and short-time circuit connection in order to improve production efficiency, and radical polymerization adhesives that can achieve these are also widely used (for example, Patent Document 1 below).

Japanese Patent Laid-Open No. 2004-197016

  Regarding the film-like circuit connecting material, it is conceivable to increase the elastic modulus of the film-like circuit connecting material in order to improve the resistance to the stress generated at the joint. However, when the elastic modulus of the film-like circuit connecting material is increased, the flexibility of the film-like circuit connecting material is increased, and the film-like circuit connecting material using PET or the like as a support, for example, at room temperature (25 ° C.) to 35 ° C. When the reel is formed at a temperature, the resin that is a constituent component of the film-like circuit connecting material oozes out. As a result, when the film-like circuit connecting material is unwound, the film-like circuit connecting material is peeled off from the support and blocking is likely to occur.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a film-like circuit connection material capable of suppressing the seepage of resin in a reel-like state as compared with the conventional art, and a circuit connection structure using the same. And

  As a result of intensive studies to solve the above problems, the inventors of the present invention can solve the above problems by including a compound having a specific structure as a radical polymerizable substance in the film-like circuit connecting material. As a result, the present invention has been completed.

［式（１）中、ｍ及びｎは、各々独立に２〜３の整数を示し、Ｒ^１は、ジオール化合物の残基である２価の基を示し、Ｒ^２は、ジイソシアネート化合物の残基である２価の基を示し、Ｒ^３及びＲ^４は、各々独立に水素原子、炭素数１〜１０のアルキル基、（メタ）アクリロイルオキシ基、又は、−ＣＨ_２−Ｏ−ＣＨ_２−Ｃ（ＣＨ_２ＯＣＯ−ＣＨ＝ＣＨ_２）_３を示す。］ That is, the film-like circuit connecting material according to the present invention includes a first circuit board, a first circuit member having a first circuit electrode formed on the main surface of the first circuit board, The second circuit board and the second circuit member having the second circuit electrode formed on the main surface of the second circuit board, with the first circuit electrode and the second circuit electrode opposed to each other. A film-like circuit connecting material for electrical connection in a wet state, comprising a radical polymerizable substance, a film-forming component, a radical polymerization initiator, and conductive particles, wherein the radical polymerizable substance is The compound which has a structure represented by following formula (1) is included.

[In Formula (1), m and n each independently represent an integer of 2 to 3, R ¹ represents a divalent group that is a residue of a diol compound, and R ² represents a residue of a diisocyanate compound. R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a (meth) acryloyloxy group, or —CH ₂ —O—CH ₂ —C. It shows the _{(CH 2 OCO-CH = CH} 2) 3. ]

  In the present invention, the film-like circuit connecting material contains a radical polymerizable substance, a film forming component, a radical polymerization initiator, and conductive particles, and the radical polymerizable substance is represented by the formula (1). By including the compound having the structure, it is possible to suppress the seepage of the resin in the reeled state and to reduce the seepage of the resin as compared with the conventional case. Further, in the present invention, even when an oligomer or monomer having a relatively small molecular weight is used as the radical polymerizable substance, it is possible to suppress the seepage of the resin in a reel-shaped state as compared with the conventional case. it can. In this invention, it can suppress that blocking generate | occur | produces when unwinding a film-form circuit connection material.

  By the way, if the elastic modulus of the film-like circuit connecting material is excessively increased in order to improve the resistance to the stress generated in the joint portion, the stress relaxation property decreases, and the first circuit board or the second circuit board In some cases, sufficient adhesive force cannot be obtained at the joint with the film-like circuit connecting material. On the other hand, in the present invention, the content of the compound having the structure represented by the formula (1) is a radical polymerization from the viewpoint of obtaining a sufficient adhesive force at the joint and excellent connectivity with the circuit board. It is preferable that it is 1.4-25.0 mass parts with respect to a total of 100 mass parts of an active substance and a film formation component.

  The storage elastic modulus (E ′) at 200 ° C. of the cured product obtained by heating the film-like circuit connecting material at 180 ° C. for 40 seconds is preferably 3.0 to 13.0 MPa.

  In the conventional film-like circuit connection material, when at least one of the first circuit board and the second circuit board is a film-like circuit board, the first circuit board or the second circuit board and the film-like circuit connection material In particular, the joint portion tends to be peeled off. On the other hand, in the present invention, at least one of the first circuit board and the second circuit board may be a film-like circuit board. In this case, although at least one of the first circuit board and the second circuit board is a film-like circuit board, it is possible to prevent the joint from being peeled off.

  The circuit connection structure according to the present invention is provided between the first circuit member, the second circuit member, the first circuit member, and the second circuit member, and the first circuit electrode and the second circuit member. And a connection member for electrically connecting the circuit electrodes, wherein the connection member is a cured product of the film-like circuit connection material. In the circuit connection structure according to the present invention, the connection member is a cured product of the film-like circuit connection material, so that the circuit connection structure can be obtained while preventing the resin from bleeding.

  According to the film-like circuit connecting material according to the present invention, it is possible to suppress the seepage of the resin in the state wound in the reel shape as compared with the conventional case. Such a film-like circuit connecting material is excellent in workability because occurrence of blocking is suppressed. Moreover, according to the circuit connection structure which concerns on this invention, a circuit connection structure can be obtained, suppressing the seepage of resin. Furthermore, according to the present invention, the connectivity with the circuit board can be improved as compared with the conventional case.

It is sectional drawing which shows the film-form circuit connection material which concerns on one Embodiment of this invention. It is sectional drawing which shows the circuit connection structure which concerns on one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary. In the present specification, “(meth) acrylate” means acrylate and a corresponding methacrylate, and “(meth) acryloyloxy group” means an acryloyloxy group and a corresponding methacryloyloxy group. .

<Film-like circuit connection material>
The film-like circuit connecting material according to the present embodiment is used to electrically connect opposing circuit electrodes. FIG. 1 is a cross-sectional view showing a circuit connection material according to the present embodiment. A film-like circuit connecting material 1 shown in FIG. 1 has a resin layer 3 and a plurality of conductive particles 5 dispersed in the resin layer 3. The thickness of the circuit connection material 1 is, for example, 5 to 100 μm.

  The film-like circuit connecting material according to the present embodiment is preferably a cured product that satisfies the following conditions when heated at a temperature of 180 ° C. for 40 seconds. That is, the storage elastic modulus (E ′) at 200 ° C. of the cured product obtained by heating the film-like circuit connecting material at 180 ° C. for 40 seconds is preferably 3.0 to 13.0 MPa. In this case, the connectivity and adhesiveness between the circuit board (particularly the film-like circuit board) and the film-like circuit connecting material are further improved, and the blocking resistance is further improved to improve the workability. The storage elastic modulus can be measured with a dynamic viscoelasticity measuring apparatus. The storage elastic modulus is more preferably 7 to 10 MPa.

  When the storage elastic modulus of the cured product of the film-like circuit connecting material at 200 ° C. is less than 3.0 MPa, the first circuit board and the second circuit board (for example, the film-like circuit board) having other circuits are pressure-bonded. In some cases, the film-like circuit connecting material has insufficient rigidity resistance to the stress generated when it receives a thermal history due to, and the interval between circuits becomes wide. There is a case where the connectivity between the first circuit board and the second circuit board is deteriorated due to the wide interval between the circuits. As a result, in a display panel application, for example, a lighting failure of the liquid crystal panel may occur.

  When the storage elastic modulus of the cured product of the film-like circuit connecting material at 200 ° C. exceeds 13.0 MPa, the elastic modulus of the film-like circuit connecting material after circuit connection is too high, and the stress relaxation property of the film-like circuit connecting material May decrease, and the adhesive force between the first circuit board or the second circuit board and the film-like circuit connecting material may be extremely reduced.

  The film-like circuit connecting material according to this embodiment includes (A) a radical polymerizable substance, (B) a film forming component (film forming material), (C) a radical polymerization initiator, (D) conductive particles, At least. Hereinafter, each component will be described.

［式（１）中、ｍ及びｎは、各々独立に２〜３の整数を示し、Ｒ^１は、ジオール化合物の残基である２価の基を示し、Ｒ^２は、ジイソシアネート化合物の残基である２価の基を示し、Ｒ^３及びＲ^４は、各々独立に水素原子、炭素数１〜１０のアルキル基、（メタ）アクリロイルオキシ基（例えば、−ＯＣＯ−ＣＨ＝ＣＨ_２、−ＯＣＯ−Ｃ（ＣＨ_３）＝ＣＨ_２）、又は、−ＣＨ_２−Ｏ−ＣＨ_２−Ｃ（ＣＨ_２ＯＣＯ−ＣＨ＝ＣＨ_２）_３を示す。］ (A: radically polymerizable substance)
The radically polymerizable substance includes a compound having a structure represented by the following formula (1).

[In Formula (1), m and n each independently represent an integer of 2 to 3, R ¹ represents a divalent group that is a residue of a diol compound, and R ² represents a residue of a diisocyanate compound. R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a (meth) acryloyloxy group (for example, —OCO—CH═CH ₂ , —OCO _{-C (CH 3) = CH 2} ), or _shows a _{-CH 2 -O-CH 2 -C (} CH 2 OCO-CH = CH 2) 3. ]

  The compound having the structure represented by the formula (1) can be obtained by polymerizing a diol compound, a diisocyanate compound, and dipentaerythritol polyacrylate.

The diol compound is a compound having a hydroxyl group at each of two ends. This diol compound is a compound represented by the following formula (2). In the following formula (2), R ¹ is a divalent organic group.

  Examples of the compound represented by the formula (2) include alkanediols; alkanediols having a carbonate group and / or an ester group; dialkanolamines or trialkanolamines.

The diisocyanate compound is a compound having an isocyanate group at each of two ends. This diisocyanate compound is a compound represented by the following formula (3). In the following formula (3), R ² is a divalent organic group.

  Examples of the compound represented by the formula (3) include 2,4-tolylene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), 1,6-hexamethylene diisocyanate (HDI), and isophorone diisocyanate ( IPDI).

  Examples of dipentaerythritol polyacrylate include dipentaerythritol pentaacrylate.

  As for content of the compound which has a structure represented by Formula (1), 1.4-25.0 mass parts is preferable with respect to a total of 100 mass parts of a radically polymerizable substance and a film formation component. In this case, after the circuit board is connected, the storage elastic modulus at 200 ° C. of the cured product of the film-like circuit connection material is improved, and the connectivity between the first circuit board or the second circuit board and the film-like circuit connection material is improved. The effect which was excellent in adhesiveness is acquired, and blocking tolerance improves and workability | operativity improves.

  When the content of the compound having the structure represented by the formula (1) is less than 1.4 parts by mass, the storage elastic modulus of the cured product of the film-like circuit connecting material at 200 ° C. may be less than 3.0 MPa. is there. On the other hand, when the content of the compound having the structure represented by the formula (1) exceeds 25.0 parts by mass, the storage elastic modulus of the cured product of the film-like circuit connecting material at 200 ° C. may exceed 13.0 MPa. is there.

  From the viewpoint of improving the elastic modulus, if a low-functional radical polymerizable substance other than the compound having the structure represented by the formula (1) is substituted, the flexibility of the film-like circuit connecting material becomes too high, In film product form (reel-like film-like circuit connection material using PET as a support), the amount of resin oozes out, and when the film-like circuit connection material is unwound from the reel, the film-like circuit connection from the support A phenomenon (blocking) in which the material is peeled off easily occurs.

  As for content of the compound which has a structure represented by Formula (1), 5.0-15.0 mass parts is more preferable with respect to a total of 100 mass parts of a radically polymerizable substance and a film formation component.

  (A) As a radically polymerizable substance, you may use together the compound which has a structure represented by Formula (1), and the compound different from the said compound. The compound that can be used as the radically polymerizable substance is a substance having a functional group that is polymerized by radicals, and examples thereof include (meth) acrylates, maleimide compounds, citraconic imide resins, and nadiimide resins. These can be used alone or in combination of two or more. The radical polymerizable substance can be used in any state of a monomer and an oligomer, and the monomer and the oligomer can be used in combination.

  Examples of (meth) acrylates include methyl acrylate, ethyl acrylate, urethane acrylate, isopropyl acrylate, isobutyl acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, and dipentaerythritol pentaacrylate. 2-hydroxy-1,3-diaacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane, 2,2-bis [4- (acryloxypolyethoxy) phenyl] propane, di Cyclopentenyl acrylate, tricyclodecanyl acrylate, tris (acryloyloxyethyl) isocyanurate, bis (acryloxyethyl) isocyanate Isocyanurate, and methacrylates or the like corresponding to these. These can be used alone or in combination of two or more.

  The maleimide compound contains at least two maleimide groups in the molecule. Examples of the maleimide compound include 1-methyl-2,4-bismaleimidebenzene, N, N′-m-phenylenebismaleimide, N, N′-p-phenylenebismaleimide, and N, N′-m-toluylene. Bismaleimide, N, N′-4,4-biphenylenebismaleimide, N, N′-4,4- (3,3′-dimethylbiphenylene) bismaleimide, N, N′-4,4- (3,3 '-Dimethyldiphenylmethane) bismaleimide, N, N'-4,4- (3,3'-diethyldiphenylmethane) bismaleimide, N, N'-4,4-diphenylmethane bismaleimide, N, N'-4,4 -Diphenylpropane bismaleimide, N, N'-3,3'-diphenylsulfone bismaleimide, N, N'-4,4-diphenyl ether bismaleimide, 2 2-bis (4- (4-maleimidophenoxy) phenyl) propane, 2,2-bis (3-s-butyl-4,8- (4-maleimidophenoxy) phenyl) propane, 1,1-bis (4- (4-maleimidophenoxy) phenyl) decane, 4,4′-cyclohexylidene-bis (1- (4-maleimidophenoxy) -2-cyclohexylbenzene, 2,2-bis (4- (4-maleimidophenoxy) phenyl ) Hexafluoropropane, which can be used alone or in combination of two or more.

  Citraconimide resin is obtained by polymerizing a citraconic imide compound having at least one citraconic imide group in the molecule. Examples of the citraconimide compound include phenyl citraconimide, 1-methyl-2,4-biscitraconimide benzene, N, N′-m-phenylene biscitraconimide, N, N′-p-phenylene biscitraconimide, N , N′-4,4-biphenylenebiscitraconimide, N, N′-4,4- (3,3-dimethylbiphenylene) biscitraconimide, N, N′-4,4- (3,3-dimethyldiphenylmethane ) Biscitraconimide, N, N′-4,4- (3,3-diethyldiphenylmethane) biscitraconimide, N, N′-4,4-diphenylmethane biscitraconimide, N, N′-4,4-diphenyl Propane biscitraconimide, N, N'-4,4-diphenyl ether biscitraconimide, N, N'- , 4-Diphenylsulfonebiscitraconimide, 2,2-bis (4- (4-citraconimidophenoxy) phenyl) propane, 2,2-bis (3-s-butyl-3,4- (4-citraconimidephenoxy) ) Phenyl) propane, 1,1-bis (4- (4-citraconimidophenoxy) phenyl) decane, 4,4′-cyclohexylidene-bis (1- (4-citraconimidophenoxy) phenoxy) -2-cyclohexyl Examples include benzene and 2,2-bis (4- (4-citraconimidophenoxy) phenyl) hexafluoropropane. These can be used alone or in combination of two or more.

  The nadiimide resin is obtained by polymerizing a nadiimide compound having at least one nadiimide group in the molecule. Examples of the nadiimide compound include phenyl nadiimide, 1-methyl-2,4-bisnadiimidebenzene, N, N′-m-phenylenebisnadiimide, N, N′-p-phenylenebisnadiimide, N, N′— 4,4-biphenylenebisnadiimide, N, N′-4,4- (3,3-dimethylbiphenylene) bisnadiimide, N, N′-4,4- (3,3-dimethyldiphenylmethane) bisnadiimide, N, N ′ -4,4- (3,3-diethyldiphenylmethane) bisnadiimide, N, N'-4,4-diphenylmethane bisnadiimide, N, N'-4,4-diphenylpropane bisnadiimide, N, N'-4,4 -Diphenyl ether bisnadiimide, N, N'-4,4-diphenylsulfone bisnadiimide, 2,2-bis (4- (4-nazii Dophenoxy) phenyl) propane, 2,2-bis (3-s-butyl-3,4- (4-nadiimidophenoxy) phenyl) propane, 1,1-bis (4- (4-nadiimidophenoxy) phenyl ) Decane, 4,4′-cyclohexylidene-bis (1- (4-nadiimidophenoxy) phenoxy) -2-cyclohexylbenzene, 2,2-bis (4- (4-nadiimidophenoxy) phenyl) hexafluoro Propane is mentioned. These can be used alone or in combination of two or more.

  Further, as the radical polymerizable substance, a radical polymerizable substance having a phosphate structure may be used. Examples of the radical polymerizable substance having a phosphate ester structure include 2-methacryloyloxyethyl acid phosphate.

  (A) The content of the radical polymerizable substance is such that the conductive particles and the plastic particles as the filler are excluded from the circuit connection material from the viewpoint of the adhesive strength and connectivity between the circuit members and the resin leakage in the reel shape. The total amount of the adhesive composition is 100 parts by mass, preferably 25 to 70 parts by mass, and more preferably 35 to 67 parts by mass.

(B: film forming component)
Film-forming components, for example, when a liquid material is solidified and the composition of the circuit connection material is made into a film shape, the film is easy to handle and does not easily tear, break or stick It imparts characteristics and the like, and allows it to be handled as a film in a normal state (under normal temperature and pressure). Examples of these film forming components include phenoxy resin, polyvinyl formal resin, polystyrene resin, polyvinyl butyral resin, polyester resin, polyamide resin, xylene resin, polyurethane resin, polyester urethane resin, olefin-carboxylic acid vinyl ester copolymer (for example, Ethylene-vinyl acetate copolymer), etc. (except for those corresponding to the component (A)). A film formation component is used individually by 1 type or in combination of 2 or more types.

  Content of the said film formation component is 20-70 mass with respect to a total of 100 mass parts of a radically polymerizable substance and a film formation component from a viewpoint of the adhesive strength and connectivity of circuit members, and a resin bleed out in a reel shape. Part is preferable, and 23 to 40 parts by mass are more preferable.

(C: radical polymerization initiator)
The radical polymerization initiator is a curing agent that generates free radicals by heating or light, and can be used without particular limitation as long as it is a curing agent that decomposes by heating or irradiation with electromagnetic waves such as ultraviolet rays to generate free radicals. . Examples of radical polymerization initiators include peroxide compounds and azo compounds. Such a curing agent is appropriately selected depending on the intended connection temperature, connection time, pot life, and the like.

  Examples of the curing agent that generates free radicals include peroxyesters, dialkyl peroxides, hydroperoxides, silyl peroxides, diacyl peroxides, peroxydicarbonates, peroxyketals, and the like.

  Examples of peroxyesters include cumyl peroxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t -Hexylperoxyneodecanoate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di ( 2-ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethyl Hexanoate, t-butylperoxyisobutyrate, 1,1-bis (t-butylperoxy) cyclohexane Sun, t-hexylperoxyisopropyl monocarbonate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2,5-dimethyl-2,5-di (m- Toluoyl peroxy) hexane, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, t-butyl peroxyacetate and the like.

  Examples of the dialkyl peroxide include α, α′bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, t- Examples thereof include butyl cumyl peroxide.

  Examples of the hydroperoxide include diisopropylbenzene hydroperoxide and cumene hydroperoxide.

  Examples of the silyl peroxide include t-butyltrimethylsilyl peroxide, bis (t-butyl) dimethylsilyl peroxide, t-butyltrivinylsilyl peroxide, bis (t-butyl) divinylsilyl peroxide, tris (t- Examples include butyl) vinylsilyl peroxide, t-butyltriallylsilyl peroxide, bis (t-butyl) diallylsilyl peroxide, and tris (t-butyl) allylsilyl peroxide.

  Examples of the diacyl peroxide include isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, and succinic peroxide. , Benzoylperoxytoluene, benzoyl peroxide and the like.

  Examples of peroxydicarbonate include di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di-2-ethoxymethoxyperoxydicarbonate, Examples include di (2-ethylhexylperoxy) dicarbonate, dimethoxybutylperoxydicarbonate, di (3-methyl-3-methoxybutylperoxy) dicarbonate, and the like.

  Examples of peroxyketals include 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis ( t-Butylperoxy) -3,3,5-trimethylcyclohexane, 1,1- (t-butylperoxy) cyclododecane, 2,2-bis (t-butylperoxy) decane and the like.

  These curing agents that generate free radicals by heating or light may be used in combination with, for example, a decomposition accelerator or an inhibitor. In addition, these curing agents may be coated with a polyurethane-based or polyester-based polymer substance to form a microcapsule, thereby imparting latency. A microencapsulated curing agent is preferred because the pot life is extended.

  These curing agents that generate free radicals by heating or light are used singly or in combination of two or more.

  From the viewpoint of obtaining a sufficient curing reaction, the content of the radical polymerization initiator is preferably 3 to 15 parts by mass, more preferably 5 to 12 parts by mass with respect to 100 parts by mass in total of the radical polymerizable substance and the film forming component. .

(D: conductive particles)
The conductive particles may be particles having conductivity on the whole or on the surface, but when used for connecting circuit members having connection terminals, the average particle diameter is preferably smaller than the distance between the connection terminals.

  Examples of the conductive particles include metal particles made of Au, Ag, Ni, Cu or solder, and particles made of carbon or the like. Moreover, what made the particle | grains which consist of nonelectroconductive glass, a ceramic, or a plastics into a nucleus, and coat | covered this nucleus with the said metal, metal particle, or carbon may be used. In the case where the conductive particle is a plastic particle as a core and the core is coated with the above metal, metal particle or carbon, or a hot-melt metal particle, the contact area between the electrode and the electrode at the time of connection is improved by being deformable by heating and pressing. Increases reliability.

  Moreover, you may use the particle | grains which further coat | covered the surface of these electrically-conductive particles with polymeric resin etc. In this case, a short circuit due to contact between the particles when the content of the conductive particles is increased can be suppressed, and insulation between the electrode circuits can be improved.

  The average particle size of the conductive particles is preferably 2 to 6 μm from the viewpoint of dispersibility and conductivity. When such conductive particles are contained, the circuit connection material can be more suitably used as an anisotropic conductive adhesive.

  The content of the conductive particles is preferably 3 to 10 parts by mass with respect to a total of 100 parts by mass of the radical polymerizable substance and the film-forming component, from the viewpoints of connectivity and insulation between circuit members and adhesive strength, and 5 to 7 parts by mass. Part by mass is more preferable.

(Other)
The film-like circuit connecting material according to this embodiment may further contain (E) a filler or (F) a polymerization inhibitor. The filler is, for example, plastic particles having insulating properties (insulating particles). Examples of the plastic particles include particles made of a metal oxide, aerosil, calcium carbonate, or a thermoplastic resin such as polystyrene. Examples of the polymerization inhibitor include hydroquinone and methyl ether hydroquinone.

<Circuit connection structure>
A circuit connection structure using the circuit connection material 1 will be described. The circuit connection material 1 is a connection structure in which circuit components having one or more circuit electrodes (connection terminals) such as chip parts such as semiconductor chips, resistor chips and capacitor chips, and printed wiring boards are connected to each other. It is preferably used to form a body.

  FIG. 2 is a cross-sectional view showing the circuit connection structure according to the present embodiment. A circuit connection structure 100 shown in FIG. 2 includes a first circuit member 10, a second circuit member 20, and a connection member 1 a provided between the circuit member 10 and the circuit member 20. The circuit member 10 includes a first circuit board 11 and a first circuit electrode 13 formed on the main surface of the circuit board 11. The circuit member 20 includes a second circuit board 21 and a second circuit electrode 23 formed on the main surface of the circuit board 21. At least one of the circuit board 11 and the circuit board 21 may be a film-like circuit board (for example, a flexible board).

  The connection member 1a is a cured product formed by curing the circuit connection material 1. The connection member 1a bonds the circuit member 10 and the circuit member 20 so that the circuit electrode 13 and the circuit electrode 23 facing each other are electrically connected. Opposing circuit electrode 13 and circuit electrode 23 are electrically connected via conductive particles 5.

  The circuit board 11 and the circuit board 21 may be substrates including at least one resin selected from the group consisting of polyethylene terephthalate, polyethersulfone, epoxy resin, acrylic resin, and polyimide resin, and may be silicon, gallium, or arsenic. Or a multilayer wiring board formed of an insulating substrate made of glass, ceramics, glass / epoxy composite, or the like. The circuit electrode 13 and the circuit electrode 23 are made of a material having conductivity that can function as an electrode (for example, at least one selected from the group consisting of gold, silver, tin, platinum group metals, and indium-tin oxide). Is formed.

  In the circuit connection structure 100, for example, a laminated body in which the circuit member 10, the circuit connection material 1, and the circuit member 20 are laminated in this order so that the circuit electrode 13 and the circuit electrode 23 face each other is heated or irradiated with light. Thus, the circuit member 10 and the circuit member 20 are obtained by the method of connecting the circuit member 10 and the circuit member 20 so that the circuit electrode 13 and the circuit electrode 23 are electrically connected.

  In this method, for example, first, the circuit connection material 1 formed on the support film is pressure-bonded in a state of being bonded onto the circuit member 20, and the circuit connection material 1 is temporarily bonded by heating or light irradiation. Next, after peeling off the support film, the circuit member 10 is positioned on the circuit connection material 1 so that the circuit electrodes 13 and 23 face each other, thereby preparing a laminate. In order to prevent the influence of volatile components generated by heating during connection on the connection, the circuit member may be preheated before the connection step. The heating condition and the light irradiation condition are appropriately adjusted according to the curability of the composition in the circuit connecting material so that the circuit connecting material is cured and sufficient adhesive strength is obtained.

  Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited thereto.

Example 1
(A) As a radical polymerizable component, reactive urethane acrylate (product name: UN-5500, manufactured by Negami Kogyo Co., Ltd.) 29 parts by mass, reactive urethane acrylate (product name: UN-952, manufactured by Negami Kogyo Co., Ltd.) 1 Parts by mass, bis (acryloxyethyl) isocyanurate (product name: M-215, manufactured by Toagosei Co., Ltd.), dimethylol tricyclodecane diacrylate (product name: DCP-A, manufactured by Kyoeisha Chemical Co., Ltd.) 10 parts by mass, 3 parts by mass of 2-methacryloyloxyethyl acid phosphate (product name: P-2M, manufactured by Kyoeisha Chemical Co., Ltd.), and (B) polyester urethane resin (product name: UR- 8240, manufactured by Toyobo Co., Ltd.) in a mixed solvent of toluene / methyl ethyl ketone = 50/50 40 parts by mass (polyester urethane resin: 16 parts by mass) of the obtained 40% by mass and 30 parts by mass obtained by dissolving ethylene-vinyl acetate copolymer (product name: Everflex EV-40W) in toluene A 10% by weight solution (ethylene-vinyl acetate copolymer: 3 parts by weight) was mixed and stirred to obtain a binder resin. Further, as (D) conductive particles, Ni conductive particles having an average particle diameter of 5 μm are mixed and dispersed in 6% by mass (Ni conductive particles: 6.2 parts by mass) with respect to the binder resin, and (E) A 30% by mass solution obtained by dissolving plastic fine particles (product name: PB-3006W, manufactured by Shin-Etsu Chemical Co., Ltd.) having a particle size of 10 μm in a mixed solvent of toluene / methyl ethyl ketone = 50/50 and sufficiently dispersing the binder resin 10 parts by mass (plastic fine particles: 3.1 parts by mass) was dispersed with respect to 100 parts by mass to obtain a dispersion. To this dispersion, 7.5 parts by mass of (C) benzoyl peroxide (product name: Nyper BMT-K, manufactured by NOF Corporation) was added as a free radical generator. Further, 0.2 part by mass of 4-TEMPO (product name: LA-7RD, manufactured by Asahi Denka Kogyo Co., Ltd.) was added to the dispersion as a polymerization inhibitor (F).

  The above dispersion is applied to a PET film (product name: UH-6Y, manufactured by Teijin Ltd.) having a thickness of 50 μm on one side by using a coating apparatus, followed by drying with hot air at 70 ° C. for 5 minutes to form an adhesive layer. A film-like circuit connecting material having a thickness of 35.0 μm was obtained. The obtained film-like circuit connection material is cut into a width of 1.5 mm, and wound on a side surface of a plastic reel having an inner diameter of 100 mm and an outer diameter of 195 mm with the adhesive film surface facing inward to form a tape-like (reel-like) circuit connection. Obtained material.

(Example 2)
The amount of reactive urethane acrylate (product name: UN-952, manufactured by Negami Kogyo Co., Ltd.) was changed to 5 parts by mass, and the amount of reactive urethane acrylate (product name: UN-5500, manufactured by Negami Kogyo Co., Ltd.) was changed. A film-like circuit connecting material was produced in the same manner as in Example 1 except that the content was changed to 25 parts by mass.

(Example 3)
Reactive urethane acrylate (product name: UN-952, manufactured by Negami Kogyo Co., Ltd.) was changed to 7.5 parts by mass, and reactive urethane acrylate (product name: UN-5500, manufactured by Negami Kogyo Co., Ltd.) A film-like circuit connecting material was produced in the same manner as in Example 1 except that the blending amount was changed to 22.5 parts by mass.

Example 4
The amount of reactive urethane acrylate (product name: UN-952, manufactured by Negami Kogyo Co., Ltd.) was changed to 10 parts by mass, and the amount of reactive urethane acrylate (product name: UN-5500, manufactured by Negami Kogyo Co., Ltd.) was changed. A film-like circuit connection material was produced in the same manner as in Example 1 except that the content was changed to 20 parts by mass.

(Example 5)
The compounding amount of the reactive urethane acrylate (product name: UN-952, manufactured by Negami Kogyo Co., Ltd.) was changed to 12.5 parts by mass, and the reactive urethane acrylate (product name: UN-5500, manufactured by Negami Kogyo Co., Ltd.) A film-like circuit connecting material was produced in the same manner as in Example 1 except that the blending amount was changed to 17.5 parts by mass.

(Example 6)
The amount of reactive urethane acrylate (product name: UN-952, manufactured by Negami Kogyo Co., Ltd.) was changed to 15 parts by mass, and the amount of reactive urethane acrylate (product name: UN-5500, manufactured by Negami Kogyo Co., Ltd.) was changed. A film-like circuit connecting material was produced in the same manner as in Example 1 except that the amount was changed to 15 parts by mass.

(Example 7)
The amount of reactive urethane acrylate (product name: UN-952, manufactured by Negami Kogyo Co., Ltd.) was changed to 20 parts by mass, and the amount of reactive urethane acrylate (product name: UN-5500, manufactured by Negami Kogyo Co., Ltd.) was changed. A film-like circuit connecting material was produced in the same manner as in Example 1 except that the amount was changed to 10 parts by mass.

(Comparative Example 1)
Reactive urethane acrylate (product name: UN-952, manufactured by Negami Kogyo Co., Ltd.) is not blended, and the amount of reactive urethane acrylate (product name: UN-5500, manufactured by Negami Kogyo Co., Ltd.) is changed to 30 parts by mass. A film-like circuit connecting material was produced in the same manner as in Example 1 except that.

Table 1 shows the compositions of Examples 1 to 7 and Comparative Example 1. Note that UN-952 is a compound having a structure represented by the above formula (1), m is 2, n is 2, and R ¹ is CH ₂ CH ₂ —NH—CH ₂ CH ₂ ( Diethanolamine residue), R ² is C ₆ H ₇ (CH ₃ ) ₃ CH ₂ (isophorone diisocyanate residue), and R ³ and R ⁴ are —CH ₂ —O—CH ₂ —C (CH ₂ OCO). is -CH = _{CH 2) 3.} UN-5500 does not correspond to a compound having a structure represented by the above formula (1).

<Preparation of evaluation connector>
The adhesive surface of the circuit connection material (width 1.5 mm, length 4 cm) obtained in the examples and comparative examples was applied to a PWB-TEG substrate (wiring pitch 300 μm, plate thickness 1.0 mmt, base material E-67, copper thickness 35 μm, plating thickness (Ni: 5 μm or more, Au: 0.05 μm or more), surface treatment: electroless flash gold plating, manufactured by Hitachi Chemical Electronics Co., Ltd.) The adhesive was transferred to a PWB-TEG substrate, and then the PET film was peeled off.

  Next, after placing a flexible wiring board (a wiring pitch of 300 μm, a wiring thickness of 8 μm, a tin-plated flexible wiring board thickness of 38 μm, hereinafter referred to as “FPC” in some cases) on the transferred adhesive so that the wiring part overlaps, 350 μm A thick silicone rubber (product name: HC-30DS, manufactured by Shin-Etsu Chemical Co., Ltd.) is used as a cushioning material, and heated and pressed at 175 ° C. and 3 MPa for 5 seconds from the flexible wiring board side through a circuit connecting material. A flexible wiring board and a PWB-TEG substrate were connected to obtain a connection body.

<Characteristic evaluation>
(Evaluation of indentation)
Using a surface roughness meter, Ra (arithmetic average roughness) of the unevenness on the FPC of the above-described connected body was measured.

(Adhesive strength evaluation)
The above-mentioned connection body was peeled 90 degrees at a peeling speed of 50 mm / min to measure the adhesive force.

(Evaluation of connection resistance)
The resistance value between adjacent circuits of the FPC including the connection part of the connection body described above was measured with a multimeter (device name: TR6845, manufactured by Advantest Corporation). For the resistance value, 45 points of resistance between adjacent circuits were measured and an average value was obtained.

(Evaluation of storage modulus)
The storage elastic modulus was obtained by heating and curing the film-like circuit connecting material at 180 ° C. for 40 seconds. The obtained cured product was measured with a viscoelasticity analyzer “RSA-3” (temperature increase rate 5 ° C./min, frequency 10 Hz, measurement temperature −150 to 300 ° C.) manufactured by TA Instruments Co., Ltd., at 200 ° C. A storage modulus was obtained.

(Evaluation of resin seepage)
The resin exudation was carried out for 4 hours in a thermostatic bath at 35 ° C. with a 75 g weight attached to the tip of the circuit connection material in the form of a reel, and then from the reel-shaped circuit connection material in the width direction of the support. The amount of resin oozing out was evaluated. In Table 2, the case where there was no bleed-out was expressed as “A”, the case where there was little bleed-out was expressed as “B”, and the case where there was very large bleed-out was expressed as “C”.

  Table 2 shows the results of the characteristic evaluation. As is clear from Table 2, the circuit connection materials of Examples 1 to 7 were superior to the circuit connection material of Comparative Example 1 in terms of resin seepage. Furthermore, the circuit connection materials of Examples 1 to 6 were superior to the circuit connection material of Comparative Example 1 in connection characteristics and adhesive strength.

  DESCRIPTION OF SYMBOLS 1 ... Film-like circuit connection material, 1a ... Connection member, 10 ... 1st circuit member, 11 ... 1st circuit board, 13 ... 1st circuit electrode, 20 ... 2nd circuit member, 21 ... 2nd Circuit board, 23 ... second circuit electrode, 100 ... circuit connection structure.

Claims (5)

A first circuit board, a first circuit member having a first circuit electrode formed on a main surface of the first circuit board, a second circuit board, and the second circuit board A film for electrically connecting a second circuit member having a second circuit electrode formed on the main surface of the first circuit electrode in a state where the first circuit electrode and the second circuit electrode are opposed to each other. Circuit connection material,
Containing a radical polymerizable substance, a film-forming component, a radical polymerization initiator, and conductive particles;
The radical polymerizable substance includes a compound having a structure represented by the following formula (1),
Content of the compound which has a structure represented by said Formula (1) is a film form which is 6.9-27.8 mass parts with respect to a total of 100 mass parts of the said radically polymerizable substance and the said film formation component. Circuit connection material.

[In Formula (1), m and n each independently represent an integer of 2 to 3, R ¹ represents a divalent group that is a residue of a diol compound, and R ² represents a residue of a diisocyanate compound. R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a (meth) acryloyloxy group, or —CH ₂ —O—CH ₂ —C. It shows the _{(CH 2 OCO-CH = CH} 2) 3. ]   Content of the compound which has a structure represented by said Formula (1) is 6.9-25.0 mass parts with respect to a total of 100 mass parts of the said radically polymerizable substance and the said film formation component. 2. The film-like circuit connecting material according to 1.   The film-form circuit connection of Claim 1 or 2 whose storage elastic modulus in 200 degreeC of the hardened | cured material obtained by heating the said film-form circuit connection material for 40 seconds is 180-13.0 MPa. material.   The film-form circuit connection material as described in any one of Claims 1-3 whose at least one of a said 1st circuit board and a said 2nd circuit board is a film-form circuit board. The first circuit member, the second circuit member, the first circuit member and the second circuit member are provided between the first circuit member, the second circuit member, and the second circuit electrode. A connection member for electrical connection,
The circuit connection structure whose said connection member is the hardened | cured material of the film-form circuit connection material as described in any one of Claims 1-4.

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