CN114231240A

CN114231240A - Circuit connecting material, circuit member connecting structure, method for producing the same, and use of composition

Info

Publication number: CN114231240A
Application number: CN202111630808.4A
Authority: CN
Inventors: 横田弘; 伊泽弘行; 有福征宏; 川上晋
Original assignee: Showa Denko KK
Current assignee: Resonac Holdings Corp
Priority date: 2013-10-09
Filing date: 2014-10-08
Publication date: 2022-03-25
Also published as: KR102282829B1; CN104559902A; JP6398570B2; KR20150041748A; JP2015096603A

Abstract

The invention provides a circuit connecting material, a connecting structure of a circuit member, a method for producing the same, and an application of a composition. The invention provides a circuit connecting material which can achieve both sufficiently low connection resistance and good connection reliability even in connection at low voltage when used for connection of circuit members. A circuit connecting material for bonding a first circuit member having a first connecting terminal formed on a first substrate and a second circuit member having a second connecting terminal formed on a second substrate so that the first connecting terminal and the second connecting terminal are electrically connected to each other, wherein at least one of the first circuit member and the second circuit member is an IC chip, and the circuit connecting material comprises (a) a thermoplastic resin, (b) a radical polymerizable compound, (c) a radical polymerization initiator, and (d) an inorganic filler, and the inorganic filler (d) has a scaly shape.

Description

Circuit connecting material, circuit member connecting structure, method for producing the same, and use of composition

The present invention is a divisional application of an invention application having an application number of 201410525015.X, an application date of 2014, 10/8, and an invention name of "a circuit connecting material, a circuit member connecting structure, and a circuit member connecting structure manufacturing method".

Technical Field

The present invention relates to a circuit connecting material, a circuit member connecting structure, and a method for manufacturing a circuit member connecting structure.

Background

In the fields of semiconductors, liquid crystal displays, and the like, various adhesive materials are used to fix electronic components and to connect circuits.

For example, in connection of a liquid crystal display and a Tape Carrier Package (TCP), connection of a Flexible Printed circuit board (FPC) and a TCP, and connection of an FPC and a Printed wiring board, an anisotropic conductive adhesive in which conductive particles are dispersed in an adhesive is used in order to more reliably perform circuit connection (for example, see patent documents 1 to 4). Further, in mounting a semiconductor silicon Chip on a substrate, so-called Chip-on-glass (COG) mounting in which a semiconductor silicon Chip is directly mounted on a substrate is also performed instead of conventional wire bonding, and here, an anisotropic conductive adhesive is also applied.

As such an anisotropic conductive adhesive, for example, patent document 5 describes an anisotropic conductive adhesive containing conductive particles in an adhesive resin composition containing a radical polymerizable resin (a), an organic peroxide (B), a thermoplastic elastomer (C), a predetermined phosphoric ester (D) and a predetermined epoxy silane coupling agent (E), wherein a specific urethane acrylate is used as the radical polymerizable resin. For example, patent document 6 describes a conductive anisotropic adhesive which includes an insulating adhesive, conductive particles, and a silane coupling agent, and which conducts electricity in the thickness direction but does not conduct electricity in the surface direction.

Patent document 1: japanese laid-open patent publication No. 59-120436

Patent document 2: japanese laid-open patent publication No. 60-191228

Patent document 3: japanese laid-open patent publication No. 1-251787

Patent document 4: japanese laid-open patent publication No. 7-90237

Patent document 5: japanese patent No. 3503740

Patent document 6: japanese laid-open patent publication No. 62-62874

Patent document 7: japanese laid-open patent publication No. 2000-40418

Disclosure of Invention

In recent years, in the field of precision electronic devices, the flexibility of circuits has been increasing, and Chip-on-Plastic (COP) mounting has been carried out, in which a semiconductor silicon Chip is directly mounted on a circuit member (for example, a flexible circuit board) having a Plastic substrate such as Polyimide (PI) or polyethylene terephthalate (PET) and connection terminals formed thereon. However, circuit connecting materials and connecting conditions thereof used for conventional COG mounting have problems such as short circuits of circuits on flexible circuit boards, deformation of plastic boards during thermocompression bonding, and insufficient adhesion to plastic boards. In order to solve these problems, a circuit connecting material capable of being rapidly cured at a low temperature (e.g., 100 to 160 ℃), a low voltage (e.g., 10 to 30MPa per unit area of a bump on a chip), and a short time (e.g., 10 seconds or less) is required. In addition, high circuit definition is required in both COP mounting and COG mounting, and the area of each connection terminal on the IC chip becomes small. That is, since the pressure applied to each connection terminal increases during connection, the substrate tends to be locally subjected to the pressure. Therefore, particularly in the case of COP mounting, a low-pressure mounting technique becomes particularly important from the viewpoint of reducing damage to the plastic substrate.

While a high adhesive force can be obtained by using a conventional epoxy resin-based circuit connecting adhesive, a latent curing agent having a high activity is required for rapid curing at a low temperature, and it is difficult to achieve both storage stability and the like. In addition, the resin composition must have sufficient fluidity to achieve connection at low pressure, but when a conventional epoxy resin-based adhesive for circuit connection is used, the fluidity is insufficient.

Further, for example, when a material obtained by radical polymerization of an unsaturated compound is used as an adhesive material for COP mounting as in patent documents 5 and 6, the adhesive material can be cured quickly at a low temperature, and the fluidity of the resin composition is higher than that of a conventional epoxy resin system. However, the fluidity of the resin composition is still insufficient, and connection under low pressure (for example, 10 to 30MPa per unit area of a bump on a chip) is extremely difficult.

Furthermore, for example, a connection material containing an inorganic filler as in patent document 7 has an effect of improving connection reliability by reducing internal stress at the time of connection, but since fluidity of the connection material is reduced by the inorganic filler, connection under a low pressure (for example, 10 to 30MPa per unit area of a bump on a chip) is extremely difficult.

The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a circuit connecting material which can achieve both sufficiently low connection resistance and good connection reliability even in connection at low voltage when used for connection of circuit members. It is another object of the present invention to provide a circuit member connection structure using the circuit connecting material and a method for manufacturing the same.

The present inventors have found that a circuit connecting material containing an inorganic filler having a specific shape is particularly excellent for electrically connecting a connecting terminal of a circuit member and a connecting terminal of an IC chip, and have completed the present invention.

That is, the present invention provides a circuit connecting material for bonding a first circuit member having a first connecting terminal formed on a first substrate and a second circuit member having a second connecting terminal formed on a second substrate so that the first connecting terminal and the second connecting terminal are electrically connected, wherein at least one of the first circuit member and the second circuit member is an IC chip, the circuit connecting material comprising (a) a thermoplastic resin, (b) a radical polymerizable compound, (c) a radical polymerization initiator, and (d) an inorganic filler, and the inorganic filler has a scale-like shape.

The circuit connecting material according to the present invention has sufficiently low connection resistance when a circuit member and an IC chip are connected at low voltage, and exhibits good connection resistance even after an accelerated test at 85 ℃ and 85% RH, for example, and thus has excellent connection reliability. The circuit connecting material according to the present invention can be suitably used when the substrate of one circuit member is plastic or glass, and particularly exhibits excellent effects in the case of plastic requiring low-temperature, low-pressure, and rapid curing.

Since the circuit connecting material contains (a) a thermoplastic resin, (b) a radical polymerizable compound, and (c) a radical polymerization initiator, curing proceeds sufficiently even when the connection is performed at a low temperature, and a good connection resistance can be maintained even after an acceleration test at 85 ℃ and 85% RH, for example.

Further, since the circuit connecting material contains the inorganic filler (d) and the inorganic filler is in the form of a scale, the circuit connecting material has sufficient fluidity even when connected under low pressure, and resin removal between the circuit member and the IC chip is promoted, thereby achieving sufficiently low connection resistance. Further, since the circuit connecting material has an increased elastic modulus after curing by containing the inorganic filler, it is possible to maintain the adhesion between the circuit member and the IC chip and obtain stable connection reliability even in an accelerated test at 85 ℃ and 85% RH, for example.

Here, the inorganic filler (d) may be used without particular limitation to the composition as long as it has a scaly shape, and preferably contains at least one of alumina and boron nitride from the viewpoint of dispersibility in a circuit connecting material. By using these as an inorganic filler, resin elimination between the connection terminal of the circuit member and the connection terminal of the IC chip at the time of connection can be facilitated, and stable connection reliability can be obtained.

The amount of the inorganic filler (d) is preferably 1 to 20% by mass based on the total mass of the circuit connecting material. By setting the amount of the resin to be mixed as described above, resin removal between the connection terminal of the circuit member and the connection terminal of the IC chip at the time of connection can be facilitated, and stable connection reliability can be obtained.

In the circuit connecting material according to the present invention, the thermoplastic resin (a) preferably contains an acrylic resin having a weight average molecular weight of 1000 to 5000. By containing such an acrylic resin, the fluidity of the circuit connecting material is further improved, resin elimination between the connecting terminal of the circuit member and the connecting terminal of the IC chip at the time of connection can be further promoted, and stable connection reliability can be maintained.

The circuit connecting material according to the present invention may further contain (e) an aluminum complex represented by the following general formula (1).

[ CHEM 1 ]

[ in the general formula (1), L¹、L²And L³Each independently represents an alkaneAn oxyanion, a conjugate anion of a beta-diketone or a conjugate anion of a beta-ketoester. L is¹、L²And L³May be the same or different.]

By containing the aluminum complex, more sufficient adhesive strength can be obtained.

The circuit connecting material of the present invention may further contain (f) a silane coupling agent.

Further, the silane coupling agent preferably contains at least one alkoxysilyl group and a radical polymerizable double bond in the molecule. This further improves the adhesion.

The circuit connecting material may further contain (g) conductive particles. By containing the conductive particles, the connection reliability between electrodes (between connection terminals, etc.) to be connected can be improved, and the connection resistance can be reduced.

The invention provides a circuit connecting material, which at least comprises a conductive adhesive layer and an insulating adhesive layer, wherein the conductive adhesive layer contains (a) thermoplastic resin, (b) free radical polymerizable compound, (c) free radical polymerization initiator, (d) inorganic filler, (e) aluminum complex, (f) silane coupling agent and (g) conductive particles, the insulating adhesive layer is formed on one surface of the conductive adhesive layer, contains (a) thermoplastic resin, (b) free radical polymerizable compound, (c) free radical polymerization initiator, (d) inorganic filler, (e) aluminum complex and (f) silane coupling agent, and does not contain (g) conductive particles.

The use of such a circuit-connecting material having a conductive adhesive layer and an insulating adhesive layer facilitates handling, and therefore, the connection operation can be performed more easily.

The circuit connecting material is used for forming a gold plating layer, ITO (indium tin oxide), SiN (SiN) as a connecting terminal on a plastic substrate made of thermoplastic resin such as polyethylene terephthalate, polycarbonate, polyimide, or the like_x(silicon nitride), SiO₂A circuit member coated with a film such as (silicon dioxide) is particularly excellent in electrical connection with an IC chip. Therefore, it is suitable for use as a plastic top chipAnd (6) mounting.

The present invention also provides a connection structure of a circuit member, the connection structure of the circuit member including a first circuit member having a first connection terminal formed on a first substrate, a second circuit member having a second connection terminal formed on a second substrate, and a circuit connection member provided between the first and second circuit members and connecting the first circuit member and the second circuit member in a state where the first connection terminal and the second connection terminal are arranged to face each other, wherein the first substrate is a plastic substrate, the second circuit member is an IC chip, the circuit connection member is formed of a cured product of a circuit connection material, and the first connection terminal is electrically connected to the second connection terminal.

According to the circuit member connection structure of the present invention, since the circuit connecting material is used, the first circuit member and the second circuit member are bonded with a high adhesive force, and a state in which the connection resistance between the circuit members is low is maintained. Therefore, the connection structure of the circuit member according to the present invention has excellent connection reliability.

The present invention also provides a method for manufacturing a connection structure of a circuit member, the method comprising: the circuit connecting material is arranged between a first circuit member having a first connecting terminal formed on a substrate and a second circuit member having a second connecting terminal formed on a second substrate, the circuit connecting material is cured by heating and pressing the first circuit member and the second circuit member, and the first connecting terminal and the second connecting terminal are electrically connected while the first circuit member and the second circuit member are connected.

According to the method for manufacturing a circuit member connection structure, since the circuit connecting material is used, in the case where one of the circuit members is a circuit member made of a plastic substrate, a circuit member connection structure in which the circuit members are connected to each other with a sufficiently low connection resistance and are bonded to each other with a sufficient bonding force can be obtained, particularly in connection at a low pressure.

According to the circuit connecting material of the present invention, when used for connecting circuit members, particularly for connecting circuit members in which one circuit member is formed of a plastic substrate, it is possible to achieve both sufficiently low connection resistance and high connection reliability even in connection under low voltage.

Further, the circuit connecting material of the present invention is suitable for bonding a circuit member made of a plastic substrate to an IC chip such as a semiconductor element or a liquid crystal display element, and has excellent connection resistance and connection reliability. In particular, according to the method for producing a connection structure of a circuit member using the circuit connecting material, since the connection structure can be cured quickly at a low temperature and a low pressure, adverse effects on the circuit member can be sufficiently suppressed.

Drawings

Fig. 1 is a schematic cross-sectional view showing an embodiment of a circuit connecting material.

Fig. 2 is a schematic cross-sectional view showing an embodiment of a connection structure of a circuit member.

Fig. 3 is a schematic cross-sectional view showing an embodiment of a connection structure of a circuit member.

Fig. 4(a) to (c) are a series of process diagrams for manufacturing the connection structure of the circuit member of fig. 2.

Fig. 5(a) to (c) are a series of process diagrams for manufacturing the connection structure of the circuit member of fig. 3.

Reference numerals:

1. 40: a circuit connecting material; 5: components other than the conductive particles; 7: conductive particles; 10: a circuit connection member; 11: an insulating material; 20: a first circuit member; 21: a substrate (first substrate); 21 a: a main face; 22: a connection terminal (first connection terminal); 30: a second circuit member; 31: a substrate (second substrate); 31 a: a main face; 32: a connection terminal (second connection terminal).

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description thereof is omitted. In the present specification, "(meth) acrylic acid" means acrylic acid and methacrylic acid corresponding thereto, and the same applies to other similar expressions such as (meth) acrylate.

In the present specification, the weight average molecular weight (Mw) is a value measured by Gel Permeation Chromatography (GPC) using a calibration curve obtained from standard polystyrene under the following conditions.

(measurement conditions) apparatus: GPC-8020 detector available from Tosoh corporation: RI-8020 column, Tosoh corporation: gelpack GL-A-160-S + GL-A150 sample concentration manufactured by Hitachi chemical Co., Ltd.: 120mg/3mL solvent: injection amount of tetrahydrofuran: 60 μ L pressure: 30kgf/cm²Flow rate: 1.00mL/min

In the present specification, the glass transition temperature (Tg) is a value measured by Differential Scanning Calorimetry (DSC) under the following conditions.

(measurement conditions) apparatus: weight of sample DSC7 manufactured by Perkin Elmer: 0.01g

And (3) measuring atmosphere: temperature range under nitrogen atmosphere (flow rate: 50 ml/min): -80-200 ℃ heating rate: the determination method at 10 ℃/min comprises the following steps: the straight lines before and after the inflection point of the obtained endothermic curve were extended, and the temperature at which the straight line at a half of the distance between the 2 extended lines and the endothermic curve crossed was set as the glass transition temperature.

In the present specification, the average plane width is a value measured by a Scanning Electron Microscope (SEM) under the following conditions.

The device comprises the following steps: observation magnification of S-4500 manufactured by Hitachi high New technology of Kyoho K.K.: 1500-fold determination method: 200 particles oriented in the plane direction were randomly extracted, the long diameter portions of the particles were measured, the average value thereof was calculated, and the average value was defined as the average plane width.

The circuit connecting material according to the present embodiment contains (a) a thermoplastic resin, (b) a radical polymerizable compound, (c) a radical polymerization initiator, and (d) an inorganic filler, and the shape of the inorganic filler is defined as a scale.

(thermoplastic resin)

(a) The thermoplastic resin is a resin (polymer) having a property of being able to repeat the following process: the liquid phase is changed to a liquid state with high viscosity by heating, is freely deformed by an external force, and is hardened in a state of maintaining its shape when cooled and the external force is removed. The thermoplastic resin (a) may be a resin (polymer) having a reactive functional group having the above properties.

In addition, the circuit connecting material according to the present embodiment preferably contains an acrylic resin having a specific weight average molecular weight as one component of the thermoplastic resin. The circuit connecting material according to the present embodiment can achieve both higher fluidity and connection reliability by containing an acrylic resin having a weight average molecular weight of 1000 to 5000 as one component of a thermoplastic resin.

The weight average molecular weight of the acrylic resin is preferably 1000 to 5000 from the viewpoint of compatibility between fluidity and connection reliability, and more preferably 1200 to 4000, and even more preferably 1500 to 3000 from the viewpoint of improvement of film formability of the circuit connecting material.

From the viewpoint of sufficiently improving the fluidity of the circuit-connecting material, the glass transition temperature (Tg) of the acrylic resin is preferably less than 70 ℃, more preferably less than 30 ℃, and still more preferably less than 0 ℃. The lower limit of the glass transition temperature (Tg) of the acrylic resin is not particularly limited, and may be set to, for example, at least-80 ℃.

Further, the acrylic resin is preferably of a "nonfunctional type" having no polar or reactive functional group such as a hydroxyl group, a carboxyl group, or a glycidyl group in a side chain. By containing the "nonfunctional type" acrylic resin, the interaction with other components can be suppressed, and as a result, the fluidity of the circuit-connecting material can be further improved.

From the viewpoint of compatibility between fluidity and connection reliability, the content of the acrylic resin in the circuit-connecting material is preferably not less than 1% by mass and not more than 15% by mass, more preferably not less than 2% by mass and not more than 12% by mass, and still more preferably not less than 4% by mass and not more than 10% by mass, based on the total mass of the thermoplastic resin and the radical polymerizable compound.

Here, as the acrylic resin according to the present embodiment, a commercially available product having the above-described characteristics may be used, and a synthetic product obtained by a known synthetic method such as radical polymerization may be used.

The acrylic resin according to the present embodiment can be obtained by, for example, radical polymerization using a radical polymerization initiator and 1 or more of an acrylic monomer and an oligomer having a crosslinking property, another acrylic monomer, and a monomer copolymerizable with the acrylic monomer.

Examples of the acrylic monomer and oligomer having a crosslinking property include a polytetramethylene glycol di (meth) acrylate, a di (meth) acrylate derivative such as 1, 6-hexanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, dimethylol tricyclodecane diacrylate and 2-hydroxy-1-acryloyloxy-3-methacryloyloxypropane di (meth) acrylate, a polyethylene glycol di (meth) acrylate such as ethylene glycol di (meth) acrylate, a polypropylene glycol di (meth) acrylate such as propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1, 3-butanediol di (meth) acrylate, 2-bis [4- (methacryloyloxyethoxy) phenyl ] propane di (meth) acrylate and the like 2, any of 2-bis [4- (methacryloxypolyethoxy) phenyl ] propane di (meth) acrylate, 2-hydrogenated bis [4- (acryloyloxypolyethoxy) phenyl ] propane di (meth) acrylate, and 2, 2-bis [4- (acryloyloxyethoxypolypropoxy) phenyl ] propane di (meth) acrylate can be suitably used, but it is preferable that the side chain does not have a polar or reactive functional group such as a hydroxyl group, a carboxyl group, or a glycidyl group.

Examples of the other acrylic monomer include (meth) acrylate derivatives such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, ethylene glycol (meth) acrylate, trifluoroethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, and cyclohexyl (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylmethane tri (meth) acrylate, tetramethylolpropane tetra (meth) acrylate, diallyl phthalate and isomers thereof, triallyl isocyanurate and derivatives thereof, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like, any of these may be suitably used, but it is preferable that the side chain and the terminal have no polar or reactive functional group such as a hydroxyl group, a carboxyl group, or a glycidyl group.

Examples of the monomer copolymerizable with the acrylic monomer include styrene derivatives such as styrene, α -methylstyrene, p-chlorostyrene and chloromethylstyrene, vinyl esters such as vinyl chloride, vinyl acetate and vinyl propionate, unsaturated nitriles such as acrylonitrile, conjugated dienes such as butadiene and isoprene, and the like, and any of these monomers can be suitably used, but it is preferable that the monomer does not have a polar or reactive functional group such as a hydroxyl group, a carboxyl group and a glycidyl group at a side chain or a terminal.

(thermoplastic resin other than acrylic resin)

The circuit connecting material according to the present embodiment may be suitably used with a thermoplastic resin other than an acrylic resin. Examples of the thermoplastic resin other than the acrylic resin include phenoxy resin, polyurethane resin, polyester polyurethane resin, butyral resin (for example, polyvinyl butyral resin), polyimide resin, polyamide resin, and a copolymer having vinyl acetate as a structural unit (a vinyl acetate copolymer, for example, an ethylene-vinyl acetate copolymer). These can be used alone in 1 or mixed with 2 or more. The thermoplastic resin may contain a siloxane bond or a fluorine substituent. These resins are preferably in a state in which they are completely compatible with each other or in a state in which they are slightly phase-separated and turbid white.

From the viewpoint of satisfying both the fluidity of the circuit connecting material and the connection reliability, the glass transition temperature (Tg) of the thermoplastic resin other than the acrylic resin is preferably from-30 ℃ to 190 ℃, more preferably from-25 ℃ to 170 ℃, and still more preferably from-20 ℃ to 150 ℃.

In addition, when the circuit-connecting material is used by being molded into a film shape, the greater the Mw of the thermoplastic resin, the more easily a good film formability can be obtained, and the melt viscosity that affects the fluidity of the circuit-connecting material in the film shape can be set in a wide range.

The Mw of the thermoplastic resin other than the acrylic resin according to the present embodiment is preferably 5000 or more, more preferably 7000 or more, and still more preferably 10000 or more. When the Mw of the thermoplastic resin is 5000 or more, good film formability is easily obtained.

The Mw of the thermoplastic resin other than the acrylic resin according to the present embodiment is preferably 150000 or less, more preferably 100000 or less, and still more preferably 80000 or less. When the Mw of the thermoplastic resin is 150000 or less, good compatibility with other components is easily obtained.

The amount of the thermoplastic resin other than the acrylic resin in the circuit connecting material according to the present embodiment is preferably not less than 5% by mass, more preferably not less than 15% by mass, based on the total mass of the thermoplastic resin and the radical polymerizable compound. When the amount of the thermoplastic resin is 5 mass% or more, good film formability can be easily obtained when the circuit connecting material is molded into a film and used. The amount of the thermoplastic resin other than the acrylic resin is preferably 80% by mass or less, and more preferably 70% by mass or less, based on the total mass of the components other than the conductive particles in the circuit-connecting material. When the amount of the thermoplastic resin is 80% by mass or less, good fluidity can be easily obtained.

(radical polymerizable Compound)

(b) The radical polymerizable compound is a substance having a functional group that is polymerized by a radical. Examples of the radical polymerizable compound include (meth) acrylate compounds, maleimide compounds, and styrene derivatives. These can be used alone in 1 kind, or mixed with 2 or more kinds and used. The radical polymerizable compound may be used in either a monomer or an oligomer state, or a monomer and an oligomer may be used in combination.

Examples of the (meth) acrylate compound include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, isobutyl (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylene glycol di (meth) acrylate, 2-hydroxy-1, 3-diacryloyloxypropane, 2-bis [4- (acryloyloxymethyl) phenyl ] propane, 2-bis [4- (acryloyloxyethoxy) phenyl ] propane, dicyclopentenyl (meth) acrylate tricyclodecyl (meth) acrylate, tris (acryloyloxyethyl) isocyanurate, urethane (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol tri (meth) acrylate, propylene glycol (meth) acrylate, and propylene glycol (meth) acrylate, Isocyanuric acid ethylene oxide-modified diacrylate, and the like. These can be used alone in 1 kind, or mixed with 2 or more kinds and used.

The maleimide compound is, for example, a compound having at least 1 maleimide group. Examples of the maleimide compound include phenylmaleimide, 1-methyl-2, 4-bismaleimide benzene, N ' -m-phenylenebismaleimide, N ' -p-phenylenebismaleimide, N ' -4, 4-biphenylenedimaleimide, N ' -4,4- (3, 3-dimethylbiphenylene) bismaleimide, N ' -4,4- (3, 3-dimethyldiphenylmethane) bismaleimide, N ' -4,4- (3, 3-diethyldiphenylmethane) bismaleimide, N ' -4, 4-diphenylmethane bismaleimide, N ' -4, 4-diphenylpropane bismaleimide, N ' -4-diphenylpropylenebismaleimide, N ' -4-diphenylpropane bismaleimide, N ' -4-bis (p-phenylene bismaleimide, N ' -diphenylpropane bismaleimide, N ' -4-diphenylpropane bismaleimide, N, 4, N, 4, N, 4, N, p, N, N ' -4, 4-diphenylether bismaleimide, N ' -4, 4-diphenylsulfone bismaleimide, 2-bis (4- (4-maleimidophenoxy) phenyl) propane, 2-bis (3-s-butyl-3, 4- (4-maleimidophenoxy) phenyl) propane, 1-bis (4- (4-maleimidophenoxy) phenyl) decane, 4 ' -cyclohexylene-bis (1- (4-maleimidophenoxy) phenoxy) -2-cyclohexylbenzene, 2-bis (4- (4-maleimidophenoxy) phenyl) hexafluoropropane, and the like. These can be used alone in 1 kind, or mixed with 2 or more kinds and used.

The styrene derivative is a compound in which a hydrogen atom in the α -position or aromatic ring of styrene is substituted with a substituent.

The amount of the radical polymerizable compound is preferably 10 to 95% by mass, more preferably 30 to 80% by mass, and still more preferably 40 to 60% by mass, based on the total mass of the thermoplastic resin and the radical polymerizable compound. By setting the blending amount to the above range, a circuit connecting material having sufficient heat resistance after curing and good film formability tends to be easily obtained.

(radical polymerization initiator)

Examples of the radical polymerization initiator (c) include a peroxide compound and an azo compound which are decomposed by heating to generate free radicals. They are appropriately selected depending on the target ligation temperature, ligation time, storage stability and the like, and from the viewpoint of reactivity and storage stability, an organic peroxide or azo-based compound having a 10-hour half-life temperature of 40 ℃ or more and a 1-minute half-life temperature of 180 ℃ or less is preferable, and an organic peroxide or azo-based compound having a 10-hour half-life temperature of 60 ℃ or more and a 1-minute half-life temperature of 170 ℃ or less is more preferable.

When the connection time is 10 seconds or less, the amount of the radical polymerization initiator to be added is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, based on 100 parts by mass of the total mass of the thermoplastic resin and the radical polymerizable compound, in order to obtain a sufficient reaction rate. By setting the amount of the radical polymerization initiator to 0.1 parts by mass or more, a circuit connecting material having good adhesive strength and low connection resistance can be easily obtained while maintaining a sufficient reaction rate. On the other hand, when the amount of the radical polymerization initiator is 30 parts by mass or less, the decrease in fluidity, the increase in connection resistance, and the decrease in storage stability of the circuit connecting material are easily suppressed.

Specific examples of the radical polymerization initiator include diacyl peroxides, peroxydicarbonates, peroxyesters, peroxyketals, dialkyl peroxides, hydrogen peroxide, silyl peroxides, and the like. Further, in order to suppress corrosion of the connection terminals of the circuit member, the chlorine ion and the organic acid contained in the radical polymerization initiator are preferably 5000ppm or less. Among them, a peroxyester, a peroxyketal, a dialkyl peroxide, hydrogen peroxide, or a silyl peroxide is preferable, and a peroxyester or a peroxyketal with which high reactivity can be obtained is more preferable. These can be used alone in 1 kind, or mixed with 2 or more kinds and used.

Examples of the diacyl peroxide include isobutyryl peroxide, 2, 4-dichlorobenzoyl peroxide, 3,5, 5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinyl peroxide, benzoyl peroxide, toluene peroxide, and benzoyl peroxide.

Examples of the peroxydicarbonate include di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di-2-ethoxymethoxy peroxydicarbonate, di (2-ethylhexyl peroxydicarbonate), dimethoxybutyl peroxydicarbonate, and di (3-methyl-3-methoxybutyl peroxydicarbonate).

Examples of the peroxy ester include cumylperoxyneodecanoate, 1,3, 3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxypivalate, 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-ethylhexanoate, t-butylperoxyisobutyrate, 1-bis (t-butylperoxy) cyclohexane, 1-tetramethylbutylperoxy neodecanoate, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-butylperoxy isobutyrate, 1-bis (t-butylperoxy) cyclohexane, and, T-hexylperoxyisopropyl monocarbonate, t-butylperoxy-3, 5, 5-trimethylhexanoate, t-butylperoxylaurate, 2, 5-dimethyl-2, 5-di (m-toluoylperoxy) hexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, t-hexylperoxybenzoate, t-butylperoxyacetate, and the like.

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

Examples of the dialkyl peroxide include α, α' -bis (t-butylperoxy) diisopropylbenzene, diisopropylphenyl peroxide, 2, 5-dimethyl-2, 5-di (t-butylperoxy) hexane, and t-butylcumyl peroxide.

Examples of the hydrogen peroxide include diisopropylbenzene hydrogen peroxide and cumene hydrogen peroxide.

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

These radical polymerization initiators which generate free radicals by heating may be further mixed with a decomposition accelerator, an inhibitor and the like and used. Further, it is preferable that these radical polymerization initiators are coated with polyurethane-based or polyester-based polymer substances and microencapsulated, because the pot life is prolonged.

(inorganic Filler)

The circuit-connecting material according to the present embodiment contains (d) an inorganic filler, and the shape of the inorganic filler is defined as a scale shape. The scale-like shape refers to an indefinite shape such as a flat shape or a thin sheet like a fish scale, and includes a material having a planar direction and a thickness in a direction perpendicular to the planar direction. The scale shape is not limited to the shape of fish scales, and includes not only particles in a narrow scale shape but also particles in a shape similar to a plate, a circle, an ellipse, or a polygon.

The reason why the connection resistance between the connection terminals is reduced by using the scaly inorganic filler is not necessarily clear, but the present inventors believe that the reason is as follows: when the circuit connecting material according to the present embodiment is interposed between the first circuit member and the second circuit member and pressure is applied from either one direction or both directions of the first circuit member and the second circuit member, pressure is selectively applied in the planar direction of the inorganic filler, and resin removal of the circuit connecting material interposed between the first connecting terminal and the second connecting terminal can be promoted even when the applied pressure is low.

The reason why the connection reliability is improved is considered to be that the elastic modulus of a cured product of the circuit connecting material is improved. By increasing the elastic modulus of the cured product of the circuit connecting material, low connection resistance can be maintained even after a moisture resistance test of 85 ℃ and 85 RH%, for example.

In the adherend of the circuit connecting material according to the present embodiment, at least one of the first circuit member and the second circuit member is an IC chip such as a semiconductor element or a liquid crystal display element. The circuit connecting material according to the present embodiment, which can be connected at a low voltage, is particularly useful because a pressure is locally applied to the circuit terminal portion of the IC chip when the IC chip is mounted on the circuit member.

The average planar width of the inorganic filler is preferably 0.5 to 20 μm, more preferably 1 to 15 μm, and still more preferably 1 to 10 μm. The average thickness of the inorganic filler is preferably 0.001 to 1 μm, more preferably 0.002 to 0.8. mu.m, and still more preferably 0.005 to 0.5. mu.m. When the average plane width is 0.5 μm or more, resin elimination between the connection terminal of the IC chip and the connection terminal of the circuit member at the time of circuit connection can be facilitated, which is preferable. Further, in the case where the average planar width is 20 μm or less, the dispersibility of the inorganic filler in the circuit-connecting material becomes good, and is therefore preferable.

The inorganic filler is not particularly limited in composition as long as it has the scaly particle shape described above, and preferably contains at least one of alumina and boron nitride. By using these, the dispersibility of the inorganic filler in the circuit connecting material can be improved, and resin elimination between the connecting terminal of the circuit member and the connecting terminal of the IC chip at the time of connection can be promoted.

The type of boron nitride includes amorphous boron nitride (a-BN), hexagonal boron nitride (h-BN), cubic boron nitride (c-BN), etc., and hexagonal boron nitride (h-BN) is preferably used from the viewpoint of high lubricity and heat resistance.

When the circuit connecting material according to the present embodiment contains (g) conductive particles described later, the inorganic filler is preferably present in a state of not being combined (or integrated) with the conductive particles.

The amount of the inorganic filler is preferably 1 to 20 mass%, more preferably 1.2 to 15 mass%, and particularly preferably 1.5 to 10 mass% based on the total mass of the circuit-connecting material. When the amount is 1 to 20% by mass, resin removal between the connection terminal of the circuit member and the connection terminal of the IC chip at the time of connection can be promoted, and since the elastic modulus of the cured product of the circuit connecting material according to the present embodiment is improved, stable connection reliability can be maintained.

The circuit connecting material according to the present embodiment may further contain (e) an aluminum complex.

An aluminum complex is a molecule having aluminum with a ligand comprising an organic group attached thereto. The ligand may be a monodentate ligand having a coordination site at only one position, or may be a polydentate ligand having a coordination site at 2 or more positions. The bond of the aluminum to the ligand may be any of a hydrogen bond or a coordinate bond. Examples of the organic group include groups composed of a carbon atom, a hydrogen atom and an oxygen atom, and these may further contain a sulfur atom, a nitrogen atom and the like.

The aluminum complex is preferably represented by the following general formula (2).

[ CHEM 2 ]

[ general formula (2)In, L¹、L²And L³Each independently represents an alkoxy anion, a conjugated anion of a beta-diketone or a conjugated anion of a beta-keto ester. L is¹、L²And L³May be the same or different.]

Specific examples of the aluminum complex represented by the general formula (2) include aluminum tris (acetylacetonate), aluminum tris (ethylacetoacetate), aluminum bis (ethylacetoacetate) monoacetylacetonate, aluminum bis (oleyl acetoacetate) monoacetylacetonate, ethyl diisopropoxyaluminum acetoacetate, and alkyl diisopropoxyaluminum acetoacetate.

These can be used alone in 1 kind, or mixed with 2 or more kinds and used.

The amount of the aluminum complex to be mixed in the circuit connecting material is not particularly limited, and may be, for example, 0.1 to 20 parts by mass when the total mass of the thermoplastic resin and the radical polymerizable compound is 100 parts by mass. From the viewpoint of cured physical properties, the amount is preferably 0.5 to 15 parts by mass, more preferably 1 to 10 parts by mass.

The circuit-connecting material according to the present embodiment may further contain (f) a silane coupling agent.

The silane coupling agent is a compound having an alkoxysilyl group (Si-OR) in its molecule. The silane coupling agent is not particularly limited, and for example, compounds represented by the following general formulae (6) to (8) having at least 1 alkoxysilyl group (Si — OR) in the molecule can be used.

X-R²¹-Si(OR²²)₃ (6)

X-R²¹-SiR²³(OR²²)₂ (7)

X-R²¹-Si(R²³)₂-OR²² (8)

[ formulae (6) to (8) wherein R²¹Represents an alkylene group having 1 to 6 carbon atoms, R²²And R²³Each independently represents a linear or branched alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, a phenyl group or a substituted phenyl group, and X represents a ureido group, a 3, 4-epoxycyclohexyl group, a glycidyloxy group, an isocyanate group, a vinyl group, a methyl groupAcryloxy, acryloxy or mercapto.]

In addition, X in the formulae (6) to (8) preferably contains a group having a radical polymerizable double bond such as a (meth) acryloyloxy group. This further improves the adhesion.

Specific examples of the silane coupling agent include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane.

These can be used alone in 1 kind, or mixed with 2 or more kinds and used.

The content of the silane coupling agent in the circuit connecting material is not particularly limited, and may be, for example, 0.1 to 30 parts by mass when the total mass of the thermoplastic resin and the radical polymerizable compound is 100 parts by mass. From the viewpoint of adhesion, the amount is preferably 1 to 20 parts by mass, and more preferably 2 to 10 parts by mass.

The circuit connecting material according to the present embodiment may further contain (g) conductive particles.

Examples of the conductive particles include metal particles such as Au, Ag, Ni, Cu, and solder, and conductive substances such as carbon. In order to obtain sufficient storage stability, the surface layer is preferably made of a noble metal such as Au or Ag, and more preferably Au. Further, a coating layer may be formed on the surface of a transition metal such as Ni or Cu using a noble metal such as Au or Ag. Further, particles in which a coating layer is formed on the surface of non-conductive glass, ceramics, plastics, or the like with the above-mentioned conductive substance may be used, and in this case, particles in which the coating layer is formed of a noble metal are also preferable.

When particles formed by coating a nonconductive plastic or the like with a conductive material or hot-melt metal particles are used as the conductive particles, these conductive particles are deformed by heating and pressing, and therefore, the contact area with the electrode at the time of connection increases, and the thickness of the electrode in the absorption circuit member tends to vary, which is preferable.

From the viewpoint of obtaining good resistance, the thickness of the noble metal-based coating layer is preferably 10nm or more. However, in the case where a noble metal-based layer is provided on a transition metal-based layer such as Ni or Cu, free radicals are generated by redox action due to defects of the noble metal-based layer, and the storage stability tends to be lowered, and therefore, from the viewpoint of preventing the above problem, the thickness of the coating layer is preferably 30nm or more. The upper limit of the thickness of the coating layer is not particularly limited, but is preferably 1 μm or less because the obtained effect gradually saturates.

The average particle diameter of the conductive particles can be determined by SEM observation. The average particle diameter of the conductive particles is preferably 1 to 18 μm from the viewpoint of good dispersibility and conductivity. The amount of the conductive particles is preferably 0.1 to 60 parts by volume per 100 parts by volume of the components other than the conductive particles in the circuit connecting material, and is preferably adjusted within this range as appropriate depending on the application. In addition, from the viewpoint of preventing short circuit of adjacent circuits due to excessive presence of conductive particles, the amount to be added is more preferably 0.1 to 30 parts by volume.

(stabilizers)

In order to control the curing rate and further improve the storage stability, a stabilizer may be added to the circuit connecting material according to the present embodiment. As such a stabilizer, known compounds can be used without particular limitation, and examples thereof include quinone derivatives such as benzoquinone and hydroquinone, phenol derivatives such as 4-methoxyphenol and 4-t-butylcatechol, aminoxy derivatives such as 2,2,6, 6-tetramethylpiperidin-1-oxy and 4-hydroxy-2, 2,6, 6-tetramethylpiperidin-1-oxy, and hindered amine derivatives such as tetramethylpiperidylmethacrylate. The stabilizer may be used alone in 1 kind or in combination of 2 or more kinds.

The amount of the stabilizer to be added is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, and still more preferably 0.02% by mass or more, based on the total mass of the components other than the conductive particles in the circuit-connecting material. When the amount is 0.005% by mass or more, the curing rate tends to be easily controlled and the storage stability tends to be easily improved. The amount of the stabilizer to be added is preferably 10% by mass or less, more preferably 8% by mass or less, and still more preferably 5% by mass or less, based on the total mass of the components other than the conductive particles in the circuit-connecting material. When the amount is 10% by mass or less, the polymer tends to be easily dissolved in other components.

(other Components)

The circuit-connecting material according to the present embodiment may further contain a softening agent, an aging inhibitor, a flame retardant, a coloring matter, a thixotropic agent, a phenol resin, a melamine resin, an isocyanate, and the like.

(one embodiment of Circuit connecting Material)

The circuit connecting material according to the present embodiment may be molded into a film shape and used. Fig. 1 is a schematic cross-sectional view showing one embodiment of a circuit connecting material. The circuit connecting material 1 is a circuit connecting material for bonding a first circuit member having a first connecting terminal formed on a first substrate and a second circuit member having a second connecting terminal formed on a second substrate so that the first connecting terminal and the second connecting terminal are electrically connected.

The circuit-connecting material according to the present embodiment may have a multilayer structure (not shown) including 2 or more layers. For example, a 2-layer film type circuit connecting material comprises a conductive adhesive layer containing conductive particles and an insulating adhesive layer formed on one surface of the conductive adhesive layer, and both the conductive adhesive layer and the insulating adhesive layer contain a thermoplastic resin, a radical polymerizable compound, a radical polymerization initiator, an inorganic filler, an aluminum complex, and a silane coupling agent. In the conductive adhesive layer, the inorganic filler is preferably present in a state of not being combined (or integrated) with the conductive particles. The thermoplastic resin, the radical polymerizable compound, the radical polymerization initiator, the inorganic filler, the aluminum complex, and the silane coupling agent contained in the conductive adhesive layer and the insulating adhesive layer may be the same or different. The inorganic filler having a scaly shape defined in the present invention may be contained in at least one layer.

When the circuit-connecting material according to the present embodiment is in the form of a film having a multilayer structure, for example, a multilayer film-type circuit-connecting material can be produced by producing each layer separately and then bonding the layers together. For example, in the case of a 2-layer film type circuit connecting material comprising a conductive adhesive layer containing conductive particles and an insulating adhesive layer formed on one surface of the conductive adhesive layer, the conductive adhesive layer can be produced by the following method: a coating apparatus is used to coat a support (such as a PET (polyethylene terephthalate) film) with a composition in which the components of the conductive adhesive layer are dissolved in a solvent, and the composition is dried with hot air for a predetermined time at a temperature at which the composition does not cure. Similarly, an insulating adhesive layer may be formed. Then, the conductive adhesive layer and the insulating adhesive layer are laminated using, for example, a hot roll laminator, whereby a 2-layer film type circuit connecting material can be produced. The thickness of the conductive adhesive layer can be set to 1 to 10 μm, the thickness of the insulating adhesive layer can be set to 5 to 40 μm, and the thickness of the entire 2-layer film type circuit connecting material can be set to 6 to 50 μm, for example.

(connection structure of Circuit Member)

Fig. 2 is a schematic cross-sectional view showing one embodiment of a connection structure of a circuit member. As shown in fig. 2, the circuit member connection structure of the present embodiment includes a first circuit member 20 formed of a substrate 21 and a second circuit member 30 formed of a substrate 31 which face each other, and a circuit connection member 10 for connecting the first circuit member 20 and the second circuit member 30 is provided between them.

The first circuit member 20 formed of the substrate 21 includes a substrate 21 (first substrate) and a connection terminal (first connection terminal) 22 formed on a main surface 21a of the substrate 21. An insulating layer (not shown) may be formed on the main surface 21a of the substrate 21 as appropriate.

As the first circuit member 20, for example, there is no special feature as long as an electrode necessary for electrical connection is formedOtherwise, the method is limited. Specifically, a circuit member including a substrate having a connection terminal formed of ITO used in a liquid crystal display is exemplified. The substrate is made of plastic such as Polyimide (PI) resin, polyethylene terephthalate (PET) resin, Polycarbonate (PC) resin, methacrylic resin, and cyclic olefin resin. In this embodiment, a metal containing gold, copper, aluminum, or the like, ITO (indium tin oxide), and silicon nitride (SiN) may be used_X) Silicon dioxide (SiO)₂) And the material of the inorganic material forms a circuit member having various surface states at least a part of the surface.

On the other hand, the second circuit member 30 includes a substrate (second substrate) 31 and a connection terminal (second connection terminal) 32 formed on a main surface 31a of the substrate 31. An insulating layer (not shown) may be formed on the main surface 31a of the substrate 31 as appropriate. The second circuit member 30 is an IC chip such as a semiconductor element or a liquid crystal display element.

The circuit connecting member 10 contains an insulating material 11 and conductive particles 7. The conductive particles 7 are disposed not only between the opposing

connection terminals

22 and 32 but also between the main surface 21a and the main surface 31 a. In the connection structure of the circuit member, the connection terminal 22 and the connection terminal 32 are electrically connected by the conductive particles 7.

In the connection structure of the circuit member, as described above, the opposing connection terminal 22 and connection terminal 32 are electrically connected by the conductive particles 7. Therefore, the connection resistance between the connection terminal 22 and the connection terminal 32 is sufficiently reduced. Therefore, the current can flow smoothly between the connection terminal 22 and the connection terminal 32, and the functions of the circuit can be fully exhibited.

Fig. 3 is a schematic cross-sectional view showing another embodiment of the connection structure of the circuit member. The circuit member connection structure shown in fig. 3 is the same as the circuit member connection structure according to the above embodiment except that the circuit member 10 does not contain the conductive particles 7. In the connection structure of the circuit member shown in fig. 3, the connection terminal 22 and the connection terminal 32 are electrically connected without conductive particles.

As described later, since the circuit-connecting member 10 is made of a cured product of the above-described circuit-connecting material, the circuit-connecting member 10 has sufficiently high adhesive strength to the first circuit member 20 made of the substrate 21 and the second circuit member 30 made of the substrate 31. In addition, stable adhesive strength can be obtained even under a high-temperature and high-humidity environment of 85 ℃ and 85 RH%, for example. In addition, in the connection structure of the circuit member, a state in which the adhesive strength is sufficiently high can be continued for a long time. Therefore, a change in the distance between the connection terminal 22 and the connection terminal 32 with time can be sufficiently prevented, and the long-term reliability of the electrical characteristics between the connection terminal 22 and the connection terminal 32 can be sufficiently improved.

The circuit connecting member 10 may be formed of a cured product of the circuit connecting material having the multilayer film structure. For example, the circuit connecting material may be a cured product of a circuit connecting material having at least a conductive adhesive layer containing conductive particles and an insulating adhesive layer formed on one surface of the conductive adhesive layer, and both the conductive adhesive layer and the insulating adhesive layer contain at least a thermoplastic resin, a radical polymerizable compound, a radical polymerization initiator, an aluminum complex, and a silane coupling agent. In this case, it is preferable that the height of at least one of the first connection terminal 22 and the second connection terminal 32 is 3.0 μm or less, and the conductive adhesive layer in the circuit-connecting material 1 is disposed on the side of the connection terminal having a height of 3.0 μm or less.

(method of manufacturing connection Structure of Circuit Member)

Next, a method for manufacturing the connection structure of the circuit member will be described. Fig. 4 and 5 are a series of process drawings for manufacturing a connection structure of a circuit member.

First, the first circuit member 20 and the circuit connecting material 40 are prepared (see fig. 4 a and 5 a). The circuit-connecting material 40 may contain the components 5 other than the conductive particles and the conductive particles 7, or may contain only the components 5 other than the conductive particles.

The thickness of the circuit connecting material 40 is preferably 10 to 50 μm. If the thickness of the circuit-connecting material 40 is 10 μm or more, the circuit-connecting material can be sufficiently filled between the

connection terminals

22 and 32, which is preferable. On the other hand, if it is 50 μm or less, it is preferable because it is possible to achieve both elimination and filling of the circuit connecting material between the connection terminal 22 and the connection terminal 32, and it is possible to ensure conduction and connection reliability.

Then, the circuit connecting material 40 is placed on the face of the first circuit member 20 on which the connection terminals 22 are formed. When the circuit-connecting material 40 is attached to the support (not shown), the circuit-connecting material 40 is placed on the first circuit member 20 so that the side thereof faces the first circuit member 20. In this case, the circuit-connecting member 40 is in the form of a film, and therefore, handling is easy, and the circuit-connecting member 40 can be easily interposed between the first circuit member 20 and the second circuit member 30, and the operation of connecting the first circuit member 20 and the second circuit member 30 can be easily performed.

Then, the circuit-connecting material 40 is pressed in the directions of arrows a and B in fig. 4 a and 5 a, and the circuit-connecting material 40 is temporarily connected to the first circuit member 20 (see fig. 4B and 5B). At this time, the pressure may be applied while heating. However, the heating temperature is set to a temperature lower than the temperature at which the radical polymerization initiator in the circuit-connecting material 40 generates radicals.

Next, as shown in fig. 4(c) and 5(c), the second circuit member 30 is placed on the circuit connecting material 40 so that the second connecting terminal 32 faces the first circuit member 20 (i.e., so that the first connecting terminal 22 and the second connecting terminal 32 are disposed opposite to each other). When the circuit-connecting material 40 is attached to the support (not shown), the support is peeled off, and the second circuit member 30 is placed on the circuit-connecting material 40.

Then, while heating the circuit-connecting material 40, the first circuit member 20 and the second circuit member 30 are pressed in the directions of arrows a and B in fig. 4(c) and 5 (c). The heating temperature in this case is a temperature at which the radical polymerization initiator can generate radicals. The radical polymerization initiator generates radicals to initiate polymerization of the radical polymerizable compound. Thus, the circuit connecting material 40 is cured and subjected to main connection, and a connection structure of circuit members as shown in fig. 2 and 3 is obtained.

The heating temperature is set to 90 to 200 ℃, the pressurizing pressure is set to 5 to 80MPa, and the connection time is set to 1 second to 10 minutes. These conditions are appropriately selected depending on the circuit connecting material and the circuit member, and post-curing may be performed as necessary. For example, when a radical polymerizable compound and a radical polymerization initiator are used as in the present embodiment, the low-temperature, low-pressure and rapid curing may be performed by setting the heating temperature to 100 to 160 ℃, the pressurization pressure to 10 to 30MPa, and the connection time to 10 seconds or less.

By manufacturing the above-described connection structure of the circuit member, the connection resistance between the connection terminal 22 and the connection terminal 32 in the obtained connection structure of the circuit member can be sufficiently reduced.

Further, by heating the circuit connecting material 40, the component 5 other than the conductive particles is cured to form the insulating material 11 in a state where the distance between the connection terminal 22 and the connection terminal 32 is sufficiently reduced, and the first circuit member 20 and the second circuit member 30 are firmly connected by the circuit connecting member 10. That is, in the obtained circuit member connecting structure, since the circuit connecting member 10 is made of the cured product of the circuit connecting material, the adhesive strength of the circuit connecting member 10 to the first circuit member 20 or the second circuit member 30 is sufficiently improved, and particularly, the adhesive strength under high-temperature and high-humidity conditions is sufficiently improved. In addition, the state in which the adhesive strength is sufficiently high in the connection structure of the circuit member can be continued for a long time. Therefore, in the obtained circuit member connection structure, the change with time in the distance between the connection terminal 22 and the connection terminal 32 can be sufficiently prevented, and the long-term reliability of the electrical characteristics between the connection terminal 22 and the connection terminal 32 is excellent.

In the above embodiment, the circuit connecting material 40 is a material containing at least a radical polymerization initiator that generates radicals by heating, but instead of the radical polymerization initiator, a radical polymerization initiator that generates radicals only by light irradiation may be used. In this case, when the circuit-connecting material 40 is cured, light irradiation may be performed instead of heating. Further, a radical polymerization initiator that generates radicals by ultrasonic waves, electromagnetic waves, or the like may be used as necessary. In addition, an epoxy resin and a latent curing agent may also be used as the curable component.

In addition, other conductive materials may be used instead of the conductive particles 7. Examples of the other conductive material include carbon in the form of particles or short fibers, and metal wires such as Au-plated Ni wires.

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

(preparation of inorganic Filler)

As the inorganic filler, scaly BORON nitride particles (trade name: DENKA BORON NITRIDE HGP, available from electrochemical industries, Ltd.), scaly alumina particles (trade name: SERATH 02025, available from Kinsei Matec Co., Ltd.), and spherical silica particles (trade name: AEROSIL R805, available from Japan AEROSIL Co., Ltd.) were prepared.

(Synthesis example 1: Synthesis of acrylic resin AR-1)

1kg of isopropyl alcohol (hereinafter referred to as IPA) was charged into a flask equipped with a stirrer, a thermometer, a cooler and a dropping funnel, and heated to 70 ℃. Separately, a mixed solution containing 335g of nonanediol diacrylate (SIGMA-ALDRICH), 210g of n-butyl acrylate (SIGMA-ALDRICH), 4g of azobisisobutyronitrile (AIBN, SIGMA-ALDRICH) and 400g of IPA was prepared, and polymerization was carried out by continuously dropping the mixture into the flask from the dropping funnel for 5 hours. After completion of the dropwise addition, 4g of AIBN was further added and the mixture was aged at 80 ℃ for 4 hours.

After completion of the polymerization, volatile components such as unreacted monomers and solvents were removed from the reaction mixture under reduced pressure to obtain liquid AR-1. AR-1 has a weight average molecular weight of 1600 and a glass transition temperature of-70 ℃.

(Synthesis example 2 Synthesis of acrylic resin AR-2)

1kg of isopropyl alcohol (hereinafter referred to as IPA) was charged into a flask equipped with a stirrer, a thermometer, a cooler and a dropping funnel, and heated to 70 ℃. Separately, a mixed solution containing 420g of dicyclopentenyloxyethyl methacrylate (SIGMA-ALDRICH Co., Ltd.), 210g of n-butyl acrylate (SIGMA-ALDRICH Co., Ltd.), 4g of AIBN and 400g of IPA was prepared, and polymerization was carried out by continuously dropping the mixture into the flask from the dropping funnel over 5 hours. After completion of the dropwise addition, 4g of AIBN was further added and the mixture was aged at 80 ℃ for 4 hours.

After completion of the polymerization, volatile components such as unreacted monomers and solvents were removed from the reaction mixture under reduced pressure to obtain liquid AR-2. AR-2 has a weight average molecular weight of 1700 and a glass transition temperature of-51 ℃.

(Synthesis example 3 Synthesis of acrylic resin AR-3)

1kg of isopropyl alcohol (hereinafter referred to as IPA) was charged into a flask equipped with a stirrer, a thermometer, a cooler and a dropping funnel, and heated to 70 ℃. A mixed solution containing 800g of n-butyl acrylate (SIGMA-ALDRICH Co., Ltd.), 4g of AIBN and 400g of IPA was prepared, and polymerization was carried out by continuously dropping the mixture into the flask from the dropping funnel over 5 hours. After completion of the dropwise addition, 4g of AIBN was further added and the mixture was aged at 80 ℃ for 4 hours.

After completion of the polymerization, volatile components such as unreacted monomers and solvents were removed from the reaction mixture under reduced pressure to obtain liquid AR-3. The weight average molecular weight of AR-3 was 1800 and the glass transition temperature was-70 ℃.

Synthesis example 4 Synthesis of urethane acrylate UA-1

2000 parts by mass (1.00 mol) of polycaprolactone diol (aliphatic polyester diol, trade name: PLACCEL 220EB, manufactured by Daiiol chemical industries, Ltd.) having a number average molecular weight of 2000 and 5.53 parts by mass of dibutyltin dilaurate (manufactured by SIGMA-ALDRICH) were charged into a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser having a calcium chloride drying tube, and a nitrogen gas inlet tube. After sufficient introduction of nitrogen, the mixture was heated to 70 to 75 ℃ and 688 parts by mass (3.10 moles) of isophorone diisocyanate (aliphatic isocyanate, SIGMA-ALDRICH Co., Ltd.) was added dropwise to the mixture uniformly over 3 hours to effect a reaction. After the completion of the dropwise addition, the reaction was continued for about 10 hours. To this mixture, 238 parts by mass (2.05 mol) of 2-hydroxyethyl acrylate (SIGMA-ALDRICH Co.) and 0.53 parts by mass of hydroquinone monomethyl ether (SIGMA-ALDRICH Co.) were added, and the mixture was reacted for 10 hours to confirm disappearance of isocyanate by IR measurement, thereby terminating the reaction and obtaining urethane acrylate (UA-1). The weight average molecular weight of the obtained urethane acrylate was 10000. The obtained UA-1 was dissolved in methyl ethyl ketone to obtain a solid content of 40 mass%.

(Synthesis example 5 Synthesis of polyester urethane resin PEU-1)

Terephthalic acid (manufactured by SIGMA-ALDRICH) was used as the dicarboxylic acid, propylene glycol (manufactured by SIGMA-ALDRICH) and neopentyl glycol (manufactured by SIGMA-ALDRICH) were used as the diols, and 4, 4' -diphenylmethane diisocyanate (manufactured by SIGMA-ALDRICH) was used as the diisocyanate.

(step 1: Synthesis of polyester polyol)

First, terephthalic acid/propylene glycol/neopentyl glycol were mixed at a mass ratio of 59/21/3, and charged into a stainless steel autoclave equipped with a stirrer, a thermometer, a condenser, a vacuum generator, and a nitrogen introduction tube and equipped with a heater. Further, antimony trioxide as a catalyst was added in a ratio of 0.003mol per 100mol of the terephthalic acid, and choline hydroxide as a surfactant was added in a ratio of 4mol per 100mol of the terephthalic acid. Then, the mixture was heated to 250 ℃ over 2.5 hours under a nitrogen pressure of 0.35MPa, and stirred at 250 ℃ for 1 hour. Thereafter, at 4.0X 10^-3The pressure was reduced to atmospheric pressure (0.1MPa) under the conditions of MPa/min, and the mixture was stirred at 250 ℃ for 3 hours in this state. After cooling to 25 ℃, the white precipitate was taken out, washed with water, and dried under vacuum to obtain polyester polyol.

(step 2: Synthesis of polyester polyurethane PEU-1)

The polyester polyol obtained in step 1 was sufficiently dried, dissolved in toluene, and charged into a four-neck flask equipped with a stirrer, a dropping funnel, a reflux cooler, and a nitrogen inlet tube. Dibutyltin laurate as a catalyst was added in a ratio of 0.02 parts by mass to 100 parts by mass of the polyester polyol. On the other hand, 4' -diphenylmethane diisocyanate was prepared so as to be dissolved in toluene in an amount of 17 parts by mass relative to 59 parts by mass of terephthalic acid, and was charged into the dropping funnel. After the inside of the reaction system was replaced with dry nitrogen gas, heating was started, and after reflux was started, half of the 4, 4' -diphenylmethane diisocyanate solution in the dropping funnel was added at a time, and vigorously stirred. The remaining half of the solution was added dropwise over 3 hours, followed by further stirring for 1 hour. The precipitate obtained by cooling to 25 ℃ was dissolved in dimethylformamide, methanol equivalent to dimethylformamide was added, and placed in a refrigerator (5 ℃) overnight. After standing, the obtained precipitate was taken out and vacuum-dried to obtain PEU-1. The weight average molecular weight of the obtained polyester urethane resin was 45000, and the glass transition temperature was 106 ℃. The obtained polyester urethane resin was dissolved in a 1:1 solvent of methyl ethyl ketone and toluene so that the solid content became 32 mass%.

(YP-70: preparation of phenoxy resin)

A phenoxy resin (product name: YP-70, manufactured by Nippon iron chemical Co., Ltd.) dissolved in methyl ethyl ketone was prepared as a thermoplastic resin with a solid content of 40 mass%.

(M313: preparation of urethane acrylate)

A polyfunctional urethane acrylate (M313, manufactured by seikoumura chemical industries, ltd.) dissolved in methyl ethyl ketone was prepared, and the solid content was 80 mass% to obtain a radical polymerizable compound.

(INI: preparation of dilauroyl peroxide)

Dilauroyl peroxide (InI, manufactured by Wako pure chemical industries, Ltd.) dissolved in toluene was prepared as a radical polymerization initiator so that the solid content became 20 mass%.

(AC-1: preparation of aluminum Complex)

An aluminum complex was prepared by dissolving bis (ethyl acetoacetate) (2, 4-pentanedione) aluminum (Wako pure chemical industries, Ltd.; symbol: AC-1) in methyl ethyl ketone so that the solid content became 80 mass%.

(SC-1: preparation of silane coupling agent)

3-methacryloxypropyltrimethoxysilane (Wako pure chemical industries, Ltd.; symbol: SC-1) was prepared as a silane coupling agent.

(CP-1: preparation of conductive particles)

Conductive particles (CP-1) having an average particle diameter of 3 μm and a specific gravity of 2.5 were prepared, and a nickel layer having a thickness of 0.2 μm was provided on the surface of the particles having polystyrene as a core, and a gold layer having a thickness of 0.02 μm was provided on the outside of the nickel layer.

[ examples 1 to 10 and comparative examples 1 to 4] (production of Circuit connecting Material)

Each component was mixed in the mixing ratio shown in Table 1, and coated on a PET resin film having a thickness of 40 μm by a coating apparatus, and dried by hot air at 70 ℃ for 5 minutes to obtain circuit connecting materials of examples 1 to 10 and comparative examples 1 to 4 having a thickness of 20 μm.

[ TABLE 1 ]

In table 1, each numerical value represents parts by mass in terms of solid content, except for conductive particles. The numerical value of the conductive particles indicates a volume part of 100 volume parts in total relative to the components other than the conductive particles.

(evaluation of connection resistance)

The circuit-connecting materials of examples 1 to 10 and comparative examples 1 to 4 were transferred from PET resin films to (A) Polyimide (PI) substrates (38 mm × 28mm in outer shape, 0.125mm in thickness, and ITO wiring patterns (50 μm in pattern width and 50 μm in pitch) on the surface) or (B) polyethylene terephthalate (PET) substrates (38 mm × 28mm in outer shape, 0.125mm in thickness, and gold (Au) wiring patterns (50 μm in pattern width and 50 μm in pitch) on the surface) at a size of 2mm × 20 mm. An IC chip (outer shape 1.7 mm. times.17.2 mm, thickness 0.55mm, size of bump 50 μm. times.50 μm, pitch of bump 50 μm, height of bump 15 μm) was mounted by applying a load of 30MPa (conversion of bump area) at 140 ℃ for 5 seconds and applying heat and pressure. The resistance value (average value of 14-terminal measurements) between adjacent circuits of the obtained connection structure was measured with a multimeter. The resistance values were measured immediately after connection (shown as "before test" in table 2) and after a high-temperature and high-humidity test (85 ℃ c., 85% RH) for 48 hours (shown as "after test" in table 2).

[ TABLE 2 ]

Immediately after connection (before the high temperature and high humidity test), the resistance values when the circuit-connecting materials of examples 1 to 10 were used were sufficiently lower and better than those of comparative examples 1 to 4. Further, the resistance value after the high temperature and high humidity test was sufficiently lower than those of comparative examples 1 and 2, and the connection structure of the circuit member using the circuit connecting materials of examples 1 to 10 showed good connection reliability.

[ examples 11 to 16 and comparative examples 5 to 8] (production of Circuit connecting Material: 2-layer film-type Circuit connecting Material)

(preparation of conductive adhesive layer)

A thermoplastic resin, a radical polymerizable compound, a radical polymerization initiator, an aluminum complex, a silane coupling agent, and conductive particles were mixed at the mixing ratios shown in Table 3, and the mixture was coated on a 40 μm thick PET resin film using a coating apparatus, and dried with hot air at 70 ℃ for 5 minutes to prepare a 6 μm thick conductive adhesive layer.

(preparation of insulating adhesive layer)

Thermoplastic resin, radical polymerizable compound, radical polymerization initiator, aluminum complex, and silane coupling agent were mixed at the mixing ratios shown in table 4, and the mixture was coated on a PET resin film having a thickness of 40 μm using a coating apparatus, and dried with hot air at 70 ℃ for 5 minutes to prepare an insulating adhesive layer having an adhesive layer thickness of 14 μm.

(2 production of film-type Circuit connecting Material having a layer Structure)

The conductive adhesive layer and the insulating adhesive layer were bonded to each other using a hot roll laminator to obtain 2-layer film type circuit connecting materials of examples 11 to 16 and comparative examples 5 to 8.

[ TABLE 3 ]

[ TABLE 4]

In tables 3 and 4, the respective numerical values except for the conductive particles represent parts by mass in terms of solid content. The numerical value of the conductive particles indicates a volume part of 100 volume parts in total relative to the components other than the conductive particles.

(evaluation of connection resistance)

The 2-layer film type circuit connecting materials of examples 11 to 16 and comparative examples 5 to 8 were placed in a size of 2mm × 20mm on (A) a Polyimide (PI) substrate (having an outer shape of 38mm × 28mm and a thickness of 0.125mm and having an ITO wiring pattern (pattern width 50 μm and pitch 50 μm) on the surface) or (B) a polyethylene terephthalate (PET) substrate (having an outer shape of 38mm × 28mm and a thickness of 0.125mm and a gold (Au) wiring pattern (pattern width 50 μm and pitch 50 μm) on the surface) in such a manner that a conductive adhesive layer was in contact with each substrate, and transferred from a PET resin film. An IC chip (outer shape 1.7 mm. times.17.2 mm, thickness 0.55mm, size of bump 50 μm. times.50 μm, pitch of bump 50 μm, height of bump 15 μm) was mounted by applying a load of 30MPa (conversion of bump area) at 140 ℃ for 5 seconds and applying heat and pressure. The resistance value (average value of 14-terminal measurements) between adjacent circuits of the obtained connection structure was measured with a multimeter. The resistance values were measured immediately after connection (shown as "before test" in table 5) and after a high-temperature and high-humidity test (85 ℃ c., 85% RH) for 48 hours (shown as "after test" in table 5).

[ TABLE 5 ]

Immediately after connection (before the high temperature and high humidity test), the resistance values when the circuit-connecting materials of examples 11 to 16 were used were sufficiently lower and better than those of comparative examples 5 to 8. Further, the resistance value after the high temperature and high humidity test was sufficiently lower than those of comparative examples 5 to 8, and the connection structures of the circuit connection members using the circuit connection materials of examples 11 to 16 showed good connection reliability.

Claims

1. A circuit connecting material for bonding a first circuit member having a first connecting terminal formed on a first substrate and a second circuit member having a second connecting terminal formed on a second substrate so that the first connecting terminal and the second connecting terminal are electrically connected,

at least one of the first circuit member and the second circuit member is an IC chip,

the circuit connecting material comprises (a) a thermoplastic resin, (b) a radically polymerizable compound, (c) a radical polymerization initiator, and (d) an inorganic filler,

the inorganic filler (d) is in the shape of a scale.

2. The circuit connecting material according to claim 1, wherein the (d) inorganic filler contains at least one of alumina and boron nitride.

3. The circuit connecting material according to claim 1 or 2, wherein the inorganic filler (d) is contained in an amount of 1 to 20% by mass based on the total mass of the circuit connecting material.

4. The circuit connecting material according to any one of claims 1 to 3, further comprising (g) conductive particles.

5. The circuit connecting material according to claim 4, wherein the (d) inorganic filler is present in a state of not being combined with the (g) conductive particles.

6. The circuit connecting material according to any one of claims 1 to 5, which is in the form of a film.

7. A circuit connecting material according to any one of claims 1 to 6, which is used for chip-on-plastic mounting.

8. A connection structure for a circuit member, comprising:

a first circuit member having a first connection terminal formed on the first substrate,

A second circuit member having a second connection terminal formed on a second substrate, and

a circuit connecting member provided between the first circuit member and the second circuit member and connecting the first circuit member and the second circuit member in a state where the first connecting terminal and the second connecting terminal are arranged to face each other,

the first substrate is a plastic substrate,

the second circuit member is an IC chip,

the circuit connecting member is formed of a cured product of the circuit connecting material according to any one of claims 1 to 7, and the first connecting terminal and the second connecting terminal are electrically connected.

9. A method for manufacturing a connection structure of a circuit member according to claim 8,

the circuit connecting material according to any one of claims 1 to 7 is disposed between a first circuit member having a first connecting terminal formed on the first substrate and a second circuit member having a second connecting terminal formed on the second substrate, and the circuit connecting material is heated and pressed through the first circuit member and the second circuit member to be cured, thereby bonding the first circuit member and the second circuit member and electrically connecting the first connecting terminal and the second connecting terminal.

10. An application of a composition containing (a) a thermoplastic resin, (b) a radical polymerizable compound, (c) a radical polymerization initiator, and (d) an inorganic filler, as a circuit connecting material for bonding a first circuit member having a first connecting terminal formed on a first substrate and a second circuit member having a second connecting terminal formed on a second substrate so that the first connecting terminal and the second connecting terminal are electrically connected,

the inorganic filler (d) is in the shape of a scale.

11. The use according to claim 10, wherein the (d) inorganic filler contains at least one of alumina and boron nitride.

12. The use according to claim 10 or 11, wherein the inorganic filler (d) is incorporated in an amount of 1 to 20% by mass based on the total mass of the circuit connecting material.

13. Use according to any one of claims 10 to 12, the composition further comprising (g) conductive particles.

14. The use according to claim 13, wherein the (d) inorganic filler is present in a state of not being composited with the (g) conductive particles.

15. Use according to any one of claims 10 to 14, wherein the circuit-connecting material is in the form of a film.

16. Use according to any one of claims 10 to 15, wherein the circuit-connecting material is for chip-on-plastic mounting.

17. An application of a composition containing (a) a thermoplastic resin, (b) a radical polymerizable compound, (c) a radical polymerization initiator, and (d) an inorganic filler, to the production of a circuit connecting material for bonding a first circuit member having a first connecting terminal formed on a first substrate and a second circuit member having a second connecting terminal formed on a second substrate so that the first connecting terminal and the second connecting terminal are electrically connected,

the inorganic filler (d) is in the shape of a scale.

18. The use according to claim 17, wherein the (d) inorganic filler contains at least one of alumina and boron nitride.

19. The use according to claim 17 or 18, wherein the inorganic filler (d) is incorporated in an amount of 1 to 20% by mass based on the total mass of the circuit connecting material.

20. Use according to any one of claims 17 to 19, the composition further comprising (g) conductive particles.

21. The use according to claim 20, wherein the (d) inorganic filler is present in a state of not being composited with the (g) conductive particles.

22. Use according to any one of claims 17 to 21, wherein the circuit-connecting material is in the form of a film.

23. Use according to any one of claims 17 to 22, wherein the circuit-connecting material is for chip-on-plastic mounting.