JP5141456B2 - Circuit connection material and connection structure - Google Patents

Abstract

Disclosed is a circuit connecting material (50) for connecting a first electrode and a second electrode facing each other, which contains an adhesive composition (52) and conductive particles (10) dispersed in the adhesive composition (52). Each conductive particle (10) comprises a core (12) mainly composed of a material having a melting point or softening point of T1 ( DEG C), a conductive layer (14) covering the surface of the core (12) and mainly composed of a low-melting-point metal having a melting point of T2 ( DEG C), and an insulating layer (16) covering the surface of the conductive layer (14) and composed of a resin composition having a softening point of T3 ( DEG C). In this connection, T1, T2 and T3 satisfy the following formula (1). T1 > T2 > T3 (1).

Description

  The present invention relates to conductive particles, a circuit connection material containing the conductive particles, and a connection structure using the circuit connection material.

  With the downsizing and thinning of electronic components, the electrodes used in the electronic components are becoming higher in density and higher in definition. An anisotropic conductive adhesive or an anisotropic conductive film is used as a circuit connection material for connecting the first electrode and the second electrode arranged to face each other. Examples of such an anisotropic conductive film include a film in which a circuit connection material composed of a plurality of conductive particles (for example, metal particles such as Ni) and an adhesive composition is formed.

  The first electrode and the second electrode that are arranged to face each other are connected by the following method. First, an anisotropic conductive film is interposed between the first electrode and the second electrode in a state where the first electrode and the second electrode are arranged to face each other. Thereafter, the structure composed of the first and second electrodes and the anisotropic conductive film is heated and pressed in the opposite direction. At this time, the first electrode and the second electrode are bonded and fixed to each other by curing the anisotropic conductive film. Thus, the first electrode and the second electrode arranged to face each other are electrically connected while maintaining the insulation between the adjacent first and second electrodes.

  In the connection method described above, the electrical continuity between the first electrode and the second electrode arranged to face each other is that the conductive particles in the anisotropic conductive film mainly contact the first and second electrodes. Obtained by. However, in such connection, since conduction is obtained by contact between metals having a high melting point, contact resistance is large, and long-term connection reliability is insufficient.

Therefore, as an attempt to reduce the contact resistance, for example, it is proposed to provide a plurality of different metal layers on the surface of the base material and to use low melting point indium, tin, tin-lead alloy as a main component as the outermost layer ( For example, see Patent Documents 1 and 2). In this case, the outermost layer of the conductive particles is melted by heating, and the melted low melting point metal is metal-bonded to the first and second electrodes, so that the gap between the first electrode and the second electrode arranged opposite to each other is increased. The connection resistance can be lowered.
JP 2002-170427 A Japanese Patent No. 3542611

  However, when the conductive particles as in Patent Documents 1 and 2 are used, the low melting point metal on the surface has a very large surface tension in the molten state. Therefore, when the electrodes are connected by heating and pressing, they are adjacent to each other. The conductive particles come into contact with each other and are easily fused. As a result, adjacent electrodes tend to conduct and short-circuit (short). Such a tendency becomes more prominent as the pitch between the adjacent first electrodes and the second electrode becomes narrower.

The present invention has been made in view of the above circumstances, and can achieve both high insulation between electrodes adjacent to each other on the same substrate and sufficient conductivity between electrodes arranged opposite to each other at a high level. and an object to provide a circuit connecting materials with excellent enough that it is possible to maintain a good insulating property and good electrical conductivity over a long period of time connection reliability. In addition, by using the circuit connection material having the above characteristics, sufficient insulation between adjacent electrodes on the same substrate and conductivity between the electrodes arranged opposite to each other are sufficiently improved, and the connection reliability is sufficiently excellent. An object is to provide a connection structure.

In order to achieve the above object, in the present invention, a core mainly composed of a material having a melting point or softening point of T ₁ (° C.) and a low melting point metal having a melting point of T ₂ (° C.) covering the surface of the core. And an insulating layer made of a resin composition having a softening point of T ₃ (° C.) that covers the surface of the conductive layer, and T ₁ , T _2, and T ₃ are Conductive particles satisfying the following formula (1) are used .
T ₁ > T ₂ > T ₃ (1)

In the conductive particles in the present invention, the surface of the conductive layer mainly composed of a low melting point metal is further coated with an insulating layer. Therefore, the formation of a passive film on the surface due to exposure to an oxidizing atmosphere is sufficiently suppressed. When such conductive particles are heated, first, at the softening point T ₃ of the resin composition constituting the insulating layer on the surface, the insulating layer exhibits a flowability softened. As the insulating layer flows, the conductive layer mainly composed of a low melting point metal is exposed on the surface of the conductive particles. With further temperature increase by heating, the conductive layer at the melting point T ₂ of the low melting point metal melts. Since the passive layer is not formed on the conductive layer of the conductive particles, the conductive layer smoothly melts not only inside the layer but also its surface. For this reason, for example, when used as a circuit connection material, it is possible to more closely adhere to a metal material such as an electrode than conductive particles that do not have an insulating layer as an outermost layer.

  On the other hand, in the conventional conductive particles that do not have an insulating layer as the outermost layer, the low melting point metal is generally a material with poor oxidation resistance, and therefore the conductive layer mainly composed of the low melting point metal is easily oxidized. Then, it is considered that the surface of the oxidized conductive layer is stabilized by forming a so-called passive film. In the conductive particles having such a conductive layer as the outermost layer, even when heated, the non-oxidized low melting point metal inside the layer inside the passive film only melts, and the surface is stabilized. The dynamic membrane is difficult to melt. For this reason, when used as a circuit connection material, for example, it is considered that the electrode cannot be sufficiently adhered.

In the present invention, the melting point T ₂ of the low melting point metal which is a main component of the conductive layer of the conductive particles is preferably 130 ° C. to 250 DEG ° C..

Accordingly, when the conductive particles are heated, the conductive layer can be smoothly melted. For example, when used as a circuit connection material, the connection reliability of the connection structure can be further improved. Incidentally, in the case where the melting point T ₂ is less than 130 ° C., for example in a temperature cycle test of upper 125 ° C. or more, the low melting point metal melts, sufficiently excellent connection reliability of the connection resulting structure and sufficiently good mechanical There is a tendency for strength to be impaired. On the other hand, if the melting point T ₂ exceeds 250 ° C., during the electrode connection, there is a tendency that the low-melting metal is not sufficiently melted, excellent conductivity and connection reliability of the resulting connection structure is impaired.

  Further, in the present invention, there is provided a circuit connecting material for connecting the first electrode and the second electrode facing each other, the adhesive composition and the conductive material dispersed in the adhesive composition. And a circuit connection material having the particles.

  Since such a circuit connection material contains conductive particles having the above characteristics, when used as a circuit connection part of a connection structure, sufficient insulation between adjacent electrodes on the same substrate is obtained. Sufficient conductivity between the electrodes arranged opposite to each other can be achieved at a high level, and good insulation and good conductivity can be maintained over a long period of time.

  The conductive particles in the circuit connection material of the present invention usually have an insulating layer whose main component is a resin composition having a lower surface tension than the low melting point metal in the outermost layer. Moreover, fusion of the conductive particles in the adhesive composition can be sufficiently suppressed. Even if adjacent particles are in contact with each other, the outermost layer has an insulating layer, so that it is not electrically connected. For this reason, the insulation between the adjacent electrodes on the same substrate can be maintained at a high level. In addition, although the insulating layer is in a melted or softened state at the time of pressurization at the time of electrode connection, an external force due to pressurization does not directly act between conductive particles adjacent to each other in a direction perpendicular to the pressurization direction. Therefore, it is considered that the possibility that the inner conductive layers contact and fuse through the insulating layer is extremely low.

By the way, the external force due to pressurization at the time of electrode connection causes the insulating layer in a molten or softened state to flow or eliminate with respect to the conductive particles sandwiched between the first and second electrodes arranged opposite to each other. It acts as a force that presses the molten conductive layer against the first or second electrode. However, the conductive particles of the present invention, high the melting point or core with a material mainly containing a softening point T ₁ is present, the possibility of low-melting metal component is crushed by an external force from being scattered around is very low It has become.

Circuit connecting material of the present invention, the adhesive composition has contains a thermoplastic resin, the softening point of the adhesive composition when the T _4, you satisfy the following formula (2).
T ₁ > T ₂ > T ₃ > T ₄ (2)

Such circuit connecting material during connection of oppositely disposed electrodes, the adhesive composition having a low softening point T ₄ has sufficient fluidity. For this reason, sufficient pressure is applied to the electrodes and the conductive particles arranged opposite to each other by heating and pressurization, and the connection stability can be further improved. In addition, since the insulating layer of conductive particles is mainly composed of a resin composition having a softening point T ₃ higher than T ₄ , it is difficult to fuse even when the conductive particles come into contact with each other when flowing. Furthermore, since the insulating layer of the conductive particles not involved in the connection between the electrodes arranged opposite to each other is mainly composed of a resin composition having a softening point T ₃ higher than T ₄ , the conductive layer of the conductive particles not contacting the electrodes is It is difficult to be exposed, and it is possible to more reliably prevent the occurrence of a short circuit due to the contact between the conductive layers of the conductive particles.

In the circuit connection material of the present invention, the adhesive composition contains a thermosetting resin, and the adhesive composition has fluidity by heating, and is low in the first electrode and the second electrode. Ru der which the conductive layer mainly composed of refractory metal component is cured after bonding.

That is, when the adhesive composition constituting the circuit connection material contains a thermosetting resin, the viscosity is lowered by heating and has fluidity, and further, the curing reaction proceeds and the viscosity increases by continuing heating. It is desirable to become solid. When the temperature of the circuit connection material rises by heating and pressurization, a connection structure can be formed as described below. That is, the adhesive composition exhibits fluidity, and the conductive particles are sandwiched between the first and second electrodes. Next, the insulating layer of the conductive particles is softened to expose the low melting point metal. The low melting point metal is then melted to form a metal bond with the first and second electrodes. The viscosity of the adhesive composition is then increased and cured. The insulating layer of the conductive particles which are not involved in the connection between the oppositely disposed electrodes, the conductive layer of the conductive particles because no pressure is applied even when the temperature higher than the softening point T ₃ hardly becomes exposed, conductive particles The occurrence of a short circuit due to contact between the conductive layers can be reliably prevented.

  In this invention, it is preferable that content of an electroconductive particle is 1-10 mass% of the whole circuit connection material.

  By using a circuit connecting material having a conductive particle content of 1 to 10% by mass of the entire circuit connecting material, the connection resistance between the electrodes arranged opposite to each other is further sufficiently reduced, and adjacent electrodes on the same substrate The insulation between each other can be more sufficiently maintained.

  The circuit connection material of the present invention is preferably formed in a film shape. The circuit connection material having such a shape can very easily perform the process of connecting the circuit electrodes arranged opposite to each other.

  In the present invention, the first circuit member having the first circuit electrode formed on the main surface of the first substrate, the second circuit electrode formed on the main surface of the second substrate, The second circuit member is disposed between the first circuit electrode and the first circuit electrode, and the first circuit member is disposed between the first substrate and the second substrate. A connection structure that connects a circuit member to the circuit member, wherein the circuit connection portion includes a cured product of the above-described circuit connection material, and the first circuit electrode and the second circuit electrode are electrically conductive. Provided is a connection structure that is electrically connected via a low-melting-point metal contained in a conductive layer of particles.

  Since such a connection structure has a cured product obtained by curing the circuit connection material having the above-described characteristics at the circuit connection portion, sufficient insulation between adjacent electrodes on the same substrate and between the electrodes arranged opposite to each other are provided. Sufficient electrical conductivity can be achieved at a high level, and good insulation and good electrical conductivity can be maintained over a long period of time.

  According to the present invention, sufficient insulation between electrodes adjacent to each other on the same substrate and sufficient conductivity between electrodes arranged opposite to each other can be achieved at a high level, and good insulation and good performance can be achieved. It is possible to provide a circuit connection material that is sufficiently excellent in connection reliability that can maintain conductivity for a long period of time. Moreover, the electroconductive particle suitable for using for such a circuit connection material can be provided. Furthermore, by using a circuit connecting material containing conductive particles having the above characteristics, sufficient insulation between electrodes adjacent to each other on the same substrate and conductivity between electrodes arranged opposite to each other are sufficiently improved. A connection structure that is sufficiently excellent in reliability can be provided.

(Circuit connection material)
FIG. 1 is a cross-sectional view schematically showing a preferred embodiment of the circuit connection material of the present invention. The circuit connection material 50 in FIG. 1 has a film shape. The circuit connecting material having such a shape is less likely to cause problems such as tearing, breaking, or stickiness, and is easy to handle. The film-like circuit connection material 50 includes an adhesive composition 52 that is an insulating portion, and the conductive particles 10 dispersed in the adhesive composition 52.

  For example, the film-like circuit connecting material 50 is obtained by dissolving an adhesive composition in a solvent and dispersing conductive particles 10 on a support (PET (polyethylene terephthalate) film or the like) using a normal coating apparatus. It can be produced by applying and drying with hot air for a predetermined time at a temperature at which the adhesive composition does not cure.

  The thickness of the film-like circuit connecting material 50 is preferably 10 to 50 μm. When the thickness of the film-like circuit connection material 50 is 10 μm or more, a sufficient amount of circuit connection material can be filled between opposing circuit members, and the insulation between adjacent electrodes on the same substrate can be more sufficiently maintained. There is a tendency to be able to. In addition, when the thickness is 50 μm or less, the adhesive composition between the electrodes arranged opposite to each other can be sufficiently removed at the time of connection, and it is easy to ensure conduction between the opposed electrodes. is there.

  The content of the conductive particles 10 with respect to the total mass of the circuit connection material 50 is preferably 1 to 10% by mass. When the content ratio is 1% by mass or more, the conductivity between the electrodes facing each other after the connection structure is formed tends to be further improved. On the other hand, when the content is 10% by mass or less, there is a tendency that the insulation between circuit electrodes adjacent on the same substrate can be further improved.

  The average particle size of the conductive particles 10 is preferably 1 to 10 μm. When the average particle size of the conductive particles 10 is 1 μm or more, it tends to be easier to obtain a better connection state by absorbing irregularities on the electrode surface and variations in height between the electrodes. On the other hand, when the average particle diameter of the conductive particles 10 is 10 μm or less, adjacent electrodes on the same substrate tend not to be short-circuited even if the pitch between the electrodes is narrow.

  The conductive particles 10 may be a mixture of a plurality of particles made of the same shape, the same size, and the same material, or a plurality of particles made of different shapes, different sizes, and different materials. In the present embodiment, the conductive particles 10 may be combined with, for example, conventional conductive particles and dispersed in the adhesive composition 52. Examples of conventional conductive particles include those made of metal such as Au, Ag, Ni, Cu, Co, and solder, carbon, and the like. Also, non-conductive glass, ceramics, plastics, and the like coated with a conductive material such as the above metal can be used as conventional conductive particles. At this time, the thickness of the metal layer to be coated is preferably 0.1 μm or more in order to obtain sufficient conductivity.

  The adhesive composition 52 of the circuit connection material 50 contains, for example, a radical polymerizable compound and a radical polymerization initiator.

  The form of the circuit connecting material is not particularly limited, and may be, for example, a paste in which the conductive particles 10 are dispersed by adding an organic solvent such as toluene or ethyl acetate to each component in the adhesive composition 52.

(Conductive particles)
FIG. 2 is a cross-sectional view schematically showing a preferred embodiment of the conductive particles of the present invention. The conductive particle 10 in FIG. 2 includes a core 12, a conductive layer 14 that covers the surface 12a of the core, and an insulating layer 16 that covers the surface 14a of the conductive layer 14. The shape of the conductive particles 10 is not particularly limited, and may be substantially spherical, for example. Such conductive particles 10 are suitably used as conductive particles for circuit connection materials.

  In the present specification, the “conductive particle” does not need to show conductivity in the state of the particle, and may be any as long as it shows conductivity when the insulating layer on the surface is melted or softened.

The conductive layer 14 is mainly composed of a low melting point metal having a melting point T _2. The core 12 is mainly composed of a material having a melting point T _1m or a softening point T _1s higher than the melting point T ₂ of the low melting point metal constituting the conductive layer 14.

It is preferable that both the melting point T _1m and the softening point T _1s of the material which is the main component of the core 12 are higher than the melting point T ₂ of the low melting point metal. In the present specification, T ₁ represents a melting point T _1m or a softening point T _1s . When the material that is the main component of the core 12 is a material that does not show a clear melting point (such as amorphous), T ₁ in the above formula (1) indicates a softening point. The resin composition constituting the insulating layer 16 has a low softening point T ₃ than the melting point T _2.

Since the surface 14a of the conductive layer 14 is covered with the insulating layer 16 in the conductive particle 10, the formation of a passive film on the surface 14a is sufficiently suppressed even when the conductive particle 10 is exposed to an oxidizing atmosphere. Has been. Therefore, during the heating for connecting the electrodes facing each other, softening of the insulating layer 16, following the exposure of the conductive layer 14 due to the flow, the conductive layer 14 in the vicinity of the melting point T ₂ of the low melting point metal melts. At this time, since the conductive layer 14 melts not only inside the layer but also its surface 14a, the conductive particles 10 can be sufficiently adhered to the electrode.

The conductive layer 14 of the conductive particles 10 exhibits electrical conductivity. Low melting point metal which is a main component of the conductive layer 14 is preferably one having a melting point _{T 2} of the 130 to 250 ° C.. Examples of such a low melting point metal include various eutectic alloys, non-eutectic low melting point alloys, and single metals. Specifically, Pb82.6-Cd17.4 (melting point 248 ° C), Pb85-Au15 (melting point 215 ° C), Bi97-Na3 (melting point 218 ° C), Bi57-Sn43 (melting point 139 ° C), Sn (melting point 232 ° C) ), In97.2-Zn2.8 (melting point: 144 ° C.), In (melting point: 157 ° C.), and the like.

Melting point _{T 2} of the low melting point metal is preferably a 150 to 200 ° C.. Thereby, the heating temperature at the time of the connection of the circuit member arrange | positioned facing can be lowered | hung, raising the freedom degree of the choice of the material of the resin composition of an insulating layer mentioned later, and adhesive composition. Therefore, the thermal influence of the connection structure can be reduced.

  The thickness of the conductive layer 14 is preferably 0.1 to 1 μm. If the thickness of the conductive layer 14 is 0.1 μm or more, for example, the bonding area or contact area between the molten low melting point metal of the conductive layer 14 and a conductive member such as an electrode tends to be further increased. On the other hand, when the thickness of the conductive layer 14 is 1 μm or less, for example, even if electrodes having a narrow pitch are connected using the conductive particles 10, a short circuit between adjacent electrodes can be more reliably suppressed on the same substrate. There is a tendency.

  If the thickness of the conductive layer 14 is less than 0.1 μm, the contact area between the conductive particles 10 and the electrode to be connected is small, and thus the effect of sufficiently reducing the connection resistance tends to be difficult to obtain. On the other hand, when the thickness of the conductive layer 14 exceeds 1 μm, for example, when the conductive particles 10 are used to connect electrodes having a narrow pitch, the conductive layer tends to spread excessively in a direction perpendicular to the pressurizing direction. Short circuits between adjacent electrodes on the substrate tend to increase.

  In addition, the thickness of each layer which comprises the electrically-conductive particle 10 can be calculated | required as an average thickness of each layer when cut | disconnected by the plane which passes along the center of the electrically-conductive particle 10. FIG. This thickness can be confirmed by, for example, a scanning electron microscope.

The core 12 is mainly composed of a material having a melting point T _1m and / or a softening point T _1s higher than the melting point T ₂ of the low melting point metal that is the main component of the conductive layer 14. The T _{1 m,} preferably a _{T 2 + 20~T 2 + 2000 ℃} . T _1s is preferably T ₂ +20 to T ₂ + 2000 ° C. The material of the core 12 may be an insulating material, a conductive material, or may include both an insulating material and a conductive material. Examples of the insulating material include various rubbers such as styrene-butadiene rubber (SBR) and silicone rubber, various plastics such as polystyrene and epoxy resin, and natural products such as starch and cellulose. By using an insulating material as the main component of the core 12, the density difference between the conductive particles 10 and the adhesive composition 52 can be reduced. Thereby, the dispersibility of the conductive particles 10 in the adhesive composition 52 can be further improved.

On the other hand, by using a conductive material as the main component of the core 12, the core 12 can also pass a current, so that the conductivity of the entire conductive particle 10 can be further improved. Examples of preferable conductive materials include metals such as Au, Ag, Ni, Cu, Co, and solder, and carbon. Non-conductive glass, ceramics, plastics, etc., in which at least one of the melting point T _1m and the softening point T _1s is higher than the melting point T ₂ of the low melting point metal are covered with a metal layer such as the metal are used as the core 12 You can also At this time, the thickness of the metal layer covering the non-conductive material is preferably 0.1 μm or more from the viewpoint of obtaining sufficient conductivity.

  The “softening point” in this specification refers to the Vicat softening temperature or glass transition temperature. Vicat softening temperature is achieved by placing a test piece of the specified dimensions in the heating bath, raising the temperature of the bath with the end face of a certain cross-sectional area pressed against the center, and the end face to the test piece to a certain depth. It is the temperature at the time of biting (JIS K7206). The glass transition temperature is a peak temperature of loss tangent (tan δ) measured by dynamic viscoelasticity measurement.

  The shape of the core 12 is not particularly limited as long as it is not a shape that cannot form the conductive particles 10, and may be, for example, substantially spherical.

The resin composition constituting the insulating layer 16 is not particularly limited as long as it has a softening point T ₃ lower than the melting point T ₂ of the low melting point metal constituting the conductive layer 14. Such a resin composition preferably contains a thermoplastic resin and / or a hot melt resin. Further, base polymers or elastomers of hot melt adhesives having heat softening properties or melting points can also be preferably used. Examples of such resins include polyethylene, ethylene copolymer polymer, ethylene-vinyl acetate copolymer, polypropylene, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, polyamide, polyester, and styrene-isoprene. Copolymer, styrene-divinylbenzene copolymer, ethylene-propylene copolymer, acrylate rubber, polyvinyl acetal, acrylonitrile-butadiene copolymer, styrene, phenoxy, solid epoxy resin, polyurethane, etc. Further, natural and synthetic resins such as terpene resin and rosin, and chelating agents such as EDTA are also included. These resins may be used alone or in combination of two or more.

Softening point _{T 3} of the resin composition of the insulating layer 16 is preferably 130 to 250 ° C..

  The thickness of the insulating layer 16 is preferably 0.01 to 0.5 μm. When the thickness of the insulating layer 16 is 0.01 μm or more, the low melting point metal in which the conductive layer 14 is melted between the plurality of conductive particles 10 arranged in a direction orthogonal to the pressing direction (direction in which the electrodes face each other). Bonding between each other can be further suppressed. On the other hand, when the thickness of the insulating layer 16 is 0.5 μm or less, when the insulating layer 16 of the conductive particles 10 is pressed, the surface 14a of the conductive layer 14 is formed on the pressed portion of the conductive particles 10 even with a small pressure. Since it is exposed, the electrical conductivity between the opposing electrodes can be further improved.

(Adhesive composition)
The adhesive composition 52 contained in the circuit connection material 50 of the present embodiment contains a radical polymerizable compound and a radical polymerization initiator.

  The radical polymerizable compound is a compound having a functional group that is polymerized by radicals. Examples of the radical polymerizable compound include a (meth) acrylate compound, a maleimide compound, a citraconimide compound, and a nadiimide compound. You may use these individually by 1 type or in mixture of 2 or more types. Moreover, the radically polymerizable compound can be used in any state of a monomer or an oligomer, and a monomer and an oligomer may be used in combination.

  (Meth) acrylate compounds include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, isobutyl (meth) acrylate, etherene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, and trimethylol. Propane tri (meth) acrylate, tetramethylene glycol tetra (meth) acrylate, 2-hydroxy-1,3-diaacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane, 2,2- Bis [4- (acryloxyethoxy) phenyl] propane, dicyclopentenyl (meth) acrylate tricyclodecanyl (meth) acrylate, tris (acryloxyethyl) isocyanurate, urethane (meth) acrylate , And the like isocyanuric acid ethylene oxide-modified diacrylate. You may use these individually by 1 type or in mixture of 2 or more types. A (meth) acrylic resin is obtained by radical polymerization of the (meth) acrylate compound.

  A maleimide compound is a compound having at least one maleimide group. As maleimide compounds, phenylmaleimide, 1-methyl-2,4-bismaleimidebenzene, N, N′-m-phenylenebismaleimide, N, N′-p-phenylenebismaleimide, N, N′-4,4 -Biphenylene bismaleimide, 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′-4,4 -Diphenyl ether bismaleimide, N, N'-4,4-diphenylsulfone bismaleimide, 2,2-bis (4- (4-maleimidophenol) Xyl) phenyl) propane, 2,2-bis (3-s-butyl-3,4- (4-maleimidophenoxy) phenyl) propane, 1,1-bis (4- (4-maleimidophenoxy) phenyl) decane, 4,4'-cyclohexylidene-bis (1- (4-maleimidophenoxy) phenoxy) -2-cyclohexylbenzene, 2,2-bis (4- (4-maleimidophenoxy) phenyl) hexafluoropropane . You may use these individually by 1 type or in combination of 2 or more types.

  A citraconic imide compound is a compound having at least one citraconic imide group. Citraconimide compounds 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) bis Citraconimide, N, N′-4,4- (3,3-diethyldiphenylmethane) biscitraconimide, N, N′-4,4-diphenylmethanebiscitraconimide, N, N′-4,4-diphenylpropanebis Citraconimide, N, N′-4,4-diphenyl ether biscitraconimide, N, N′-4,4- Phenylsulfone biscitraconimide, 2,2-bis (4- (4-citraconimidophenoxy) phenyl) propane, 2,2-bis (3-s-butyl-3,4- (4-citraconimidophenoxy) phenyl) Propane, 1,1-bis (4- (4-citraconimidophenoxy) phenyl) decane, 4,4′-cyclohexylidene-bis (1- (4-citraconimidophenoxy) phenoxy) -2-cyclohexylbenzene, 2 , 2-bis (4- (4-citraconimidophenoxy) phenyl) hexafluoropropane and the like. You may use these individually by 1 type or in combination of 2 or more types.

  A nadiimide compound is a compound having at least one nadiimide group. 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-diphenylmethanebisnadiimide, N, N′-4,4-diphenylpropanebisnadiimide, N, N′-4,4-diphenyl ether Bisnadiimide, N, N′-4,4-diphenylsulfone bisnadiimide, 2,2-bis (4- (4-nadiimidophenol) Xyl) 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) hexafluoropropane Etc. You may use these individually by 1 type or in combination of 2 or more types.

  Moreover, you may use the radically polymerizable compound which has a phosphate ester structure as a radically polymerizable compound.

  A radically polymerizable compound having a phosphate structure is preferably used from the viewpoint of improving the adhesive force of the adhesive composition to an inorganic substance such as a metal. The amount of the radical polymerizable compound having a phosphate ester structure is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the total solid content of the adhesive composition 52. Preferably, 0.5 to 5 parts by mass is more preferable. The radically polymerizable compound having a phosphate ester structure is obtained as a reaction product of phosphoric anhydride and 2-hydroxyethyl (meth) acrylate. Specific examples include mono (2-methacryloyloxyethyl) acid phosphate, di (2-methacryloyloxyethyl) acid phosphate (phosphate ester dimethacrylate), and the like. You may use these individually by 1 type or in mixture of 2 or more types.

  As the radical polymerizable compound, it is preferable to use a combination of a (meth) acrylate compound and a radical polymerizable compound having a phosphate ester structure. When such a combination is used, the adhesive strength of the adhesive composition can be further improved as compared with the case where a (meth) acrylate compound and a radical polymerizable compound having a phosphate ester structure are used alone. .

  The radical polymerization initiator is not particularly limited as long as it is a compound that generates radicals by light irradiation and / or heating. As such a radical polymerization initiator, a compound that generates a radical upon irradiation with light of 150 to 750 nm and / or heating at 80 to 200 ° C. is preferable, and specifically, a peroxide, an azo compound, or the like is preferable. These are appropriately selected in consideration of the intended connection temperature, connection time, storage stability, and the like.

  As the peroxide, an organic peroxide is preferable from the viewpoint of high reactivity and storage stability. Among organic peroxides, a temperature with a half-life of 10 hours (that is, a temperature at which the half-life is 10 hours) is 40 ° C. or higher, and a temperature with a half-life of 1 minute (that is, a temperature at which the half-life is 1 minute). An organic peroxide having a temperature of 180 ° C. or lower is preferable, and an organic peroxide having a half-life of 10 hours at a temperature of 50 ° C. or higher and a half-life of 1 minute at a temperature of 170 ° C. or lower is more preferable. When the connection time is 10 seconds or less, from the viewpoint of obtaining a more sufficient reaction rate, the blending amount of the radical polymerization initiator is 1 to 20% by mass based on the total solid content of the adhesive composition 52. Preferably, 2 to 15% by mass is particularly preferable.

  Specific examples of the organic peroxide include diacyl peroxide, peroxydicarbonate, peroxyester, peroxyketal, dialkyl peroxide, hydroperoxide, silyl peroxide, and the like. Of these, peroxyesters, dialkyl peroxides, hydroperoxides, and silyl peroxides have a chlorine ion or organic acid content of usually 5000 ppm or less. For this reason, there is little organic acid generated after thermal decomposition, and it can be used particularly preferably because corrosion of the electrodes of the circuit member can be suppressed.

  Diacyl peroxide includes isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinic peroxide, benzoyl Examples include peroxytoluene and benzoyl peroxide.

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

  Peroxyesters include cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxynoedecanoate, and t-hexyl. Peroxyneodecanoate, 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-ethylhexanoate Nate, t-butylperoxyisobutyrate, 1,1-bis (t-butylperoxy) cyclohexane, -Hexylperoxyisopropyl monocarbonate, t-butylperoxy-3,5,5-trimethylhexanonate, t-butylperoxylaurate, 2,5-dimethyl-2,5-di (m-toluoyl par Oxy) hexane, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, t-butyl peroxyacetate and the like.

  Peroxyketals include 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t- Butyl peroxy) -3,3,5-trimethylcyclohexane, 1,1- (t-butylperoxy) cyclododecane, 2,2-bis (t-butylperoxy) decane and the like.

  Dialkyl peroxides include α, α′-bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, and t-butyl. Cumyl peroxide and the like.

  Examples of the hydroperoxide include diisopropylbenzene hydroperoxide and cumene hydroperoxide.

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

  These radical polymerization initiators can be used singly or in combination of two or more, and may further be used in combination with a decomposition accelerator, an inhibitor and the like.

  In addition, those obtained by coating these radical polymerization initiators with a polyurethane-based or polyester-based polymer substance and making them into microcapsules can be used preferably because the pot life can be extended. In addition to the radical polymerization initiator that generates radicals by heating or light irradiation, a radical polymerization initiator that generates radicals by ultrasonic waves, electromagnetic waves, or the like may be used as necessary. In addition, in order to suppress corrosion of the electrode of a circuit member, it is preferable that the density | concentration of the chlorine ion and organic acid which are contained in a radical polymerization initiator is 5000 ppm or less. Furthermore, a radical polymerization initiator that generates less organic acid after thermal decomposition is more preferable. Moreover, since the stability after hardening of adhesive composition improves, it is preferable to have a mass retention of 20 mass% or more after leaving open for 24 hours at room temperature and normal pressure.

  Moreover, the adhesive composition 52 may contain a radical polymerization inhibitor such as hydroquinone or methyl ether hydroquinone as long as necessary so long as the curability is not impaired.

  The adhesive composition 52 may contain a thermosetting resin other than the radical polymerizable compound. Examples of such a thermosetting resin include an epoxy resin. Epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol F novolak type epoxy resin, fat Examples thereof include cyclic epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, hydantoin type epoxy resins, isocyanurate type epoxy resins, and aliphatic chain epoxy resins. These epoxy resins may be halogenated or hydrogenated. These epoxy resins may be used alone or in combination of two or more.

  Moreover, what is used as a hardening | curing agent of a normal epoxy resin can be used as a hardening | curing agent of the said epoxy resin. Specific examples include amines, phenols, acid anhydrides, imidazoles, dicyandiamide and the like. Furthermore, tertiary amines and organic phosphorus compounds that are usually used as curing accelerators may be used as appropriate.

  Further, as a method of reacting the epoxy resin, in addition to using the above curing agent, cationic polymerization may be performed using a sulfonium salt, an iodonium salt, or the like.

The adhesive composition 52 may contain a thermoplastic resin. Examples of the thermoplastic resin include polyethylene, ethylene copolymer polymer, ethylene-vinyl acetate copolymer, polypropylene, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, polyamide, polyester, and styrene-isoprene copolymer. Examples thereof include a polymer, a styrene-divinylbenzene copolymer, an ethylene-propylene copolymer, an acrylate rubber, a polyvinyl acetal, and an acrylonitrile-butadiene copolymer. These resins may be used alone or in combination of two or more. By adjusting the kind and mixing ratio of the thermoplastic resin, it is possible to adjust the softening point T ₄ of the adhesive composition 52.

  The adhesive composition 52 may contain a polymer compound in order to impart film formability, adhesiveness, and stress relaxation during curing. Examples of the polymer compound include polyvinyl butyral resin, polyvinyl formal resin, polyester resin, polyamide resin, polyimide resin, xylene resin, phenoxy resin, polyurethane resin, urea resin, and the like.

  The polymer compound contained in the adhesive composition 52 preferably has a molecular weight of 10,000 to 10,000,000. The polymer compound is preferably modified with a radical polymerizable functional group from the viewpoint of improving the heat resistance of the circuit connecting material. Further, these polymer compounds may contain a carboxyl group. The content of the polymer compound in the adhesive composition 52 is preferably 2 to 80% by mass, more preferably 5 to 70% by mass, based on the total solid content of the adhesive composition 52. More preferably, it is 10-60 mass%. When the content of the polymer compound is 2% by mass or more, stress relaxation and adhesive force tend to be further improved. On the other hand, when the content of the polymer compound is 80% by mass or less, a decrease in fluidity of the adhesive composition tends to be more sufficiently suppressed.

  The adhesive composition 52 may appropriately contain a filler, a softener, an accelerator, an anti-aging agent, a colorant, a flame retardant, and a coupling agent.

  In the adhesive composition 52 described above, the radical polymerization initiator is preferably contained in an amount of 0.5 to 30 parts by weight, more preferably 1.0 to 10 parts by weight with respect to 100 parts by weight of the radical polymerizable compound. Is more preferable. When the content of the radical polymerization initiator is 0.5 parts by mass or more, the curing reaction proceeds sufficiently and the curing tends to be further sufficient. On the other hand, when the content of the radical polymerization initiator is 30 parts by mass or less, the adhesive composition tends to have more excellent storage stability.

In the present embodiment, the softening point T ₄ of the adhesive composition 52 preferably satisfies the above formula (2). Softening point T ₄ of the adhesive composition 52 is lower than the softening point T ₃ of the insulating layer 16 of the conductive particles 10, when connecting the oppositely disposed circuit members together, flow readily adhesive composition Therefore, the opposing electrodes can be easily electrically connected. The softening point T ₄ of the adhesive composition 52 is preferably 130 to 150 ° C. from the viewpoint of achieving both good fluidity of the adhesive composition 52 at the time of connection and the form stability of the circuit connecting material.

(Circuit member connection structure)
FIG. 3 is a cross-sectional view schematically showing a preferred embodiment of the connection structure of the present invention. The connection structure 24 shown in FIG. 3 includes a first circuit member 20 in which a plurality of first electrodes 22 are formed on the main surface 21 a of the first circuit board 21, and the main circuit board 31 of the second circuit board 31. A second circuit member 30 having a plurality of second electrodes 32 formed on the surface 31a, and a circuit connection portion 26 provided between the main surface 21a of the circuit board 21 and the main surface 31a of the circuit board 31; Is provided. Note that an insulating layer (not shown) may be formed on the main surface 21a of the circuit board 21 in some cases. In addition, an insulating layer (not shown) may be formed on the main surface 31a of the circuit board 31 according to circumstances.

The circuit members 20 and 30 are not particularly limited as long as electrodes that require electrical connection are formed. Specific examples include a glass or plastic substrate having electrodes formed of ITO or the like used for a liquid crystal display, a printed wiring board, a ceramic wiring board, a flexible wiring board, and a semiconductor silicon chip. These can be used in combination as needed. As described above, in the present embodiment, a material made of an organic material such as a printed wiring board or polyimide, a metal such as copper or aluminum, ITO (indium tin oxide), silicon nitride (SiN _x ), silicon dioxide (SiO ₂ ). Circuit members having various surface states such as inorganic materials such as the above can be used.

  The circuit connection portion 26 connects the circuit member 20 and the circuit member 30 with the circuit electrodes 22 and 32 facing each other, and contains a cured product of the above-described circuit connection material. In other words, the circuit connection portion 26 includes the core 12, the low melting point metal portion 114 made of a material mainly composed of a low melting point metal, which constitutes the conductive layer 14, and the resin composition that constitutes the insulating layer 16. Insulating resin part 116 made of a cured product, insulating part 11 made of a cured product of the adhesive composition, and conductive particles 10.

  The first electrode 22 and the second electrode 32 are electrically and mechanically connected via the low melting point metal part 114. The low-melting-point metal part 114 is bonded to the electrode 22 and the electrode 32 and solidified after the conductive layer 14 is melted. For this reason, the low melting point metal part 114 is in close contact with the electrode 22 and the electrode 32. Therefore, the connection resistance between the electrode 22 and the electrode 32 is sufficiently reduced, and the electrode 22 and the electrode 32 can be firmly fixed. As a result, the flow of current between the electrode 22 and the electrode 32 can be made smooth, and the functions of the circuit can be fully exhibited.

  Further, the electrode 22 and the electrode 32 can be more firmly fixed by the insulating resin portion 116. Furthermore, the insulating resin portion 116 can suppress the conduction between adjacent low melting point metal portions 114. Therefore, the short circuit between the adjacent first electrodes 22 (between the second electrodes 32) can be sufficiently suppressed.

  In such a connection structure 24, the connection resistance between the opposing electrode 22 and the electrode 32 can be sufficiently reduced, and insulation between the adjacent first electrodes 22 and between the adjacent second electrodes 32 can be achieved. Insulation can be maintained sufficiently. The opposing electrode 22 and electrode 32 are firmly fixed by the circuit connection portion 26.

(Method for manufacturing connection structure)
Next, a manufacturing method of the circuit member connection structure 24 described above will be described with reference to the drawings. FIG. 4 is a process cross-sectional view schematically showing an example of a method for manufacturing a connection structure according to the present invention. 4A to 4C are cross-sectional views schematically showing each step of the method for manufacturing the circuit member connection structure.

  First, the circuit member 20 and the film-like circuit connection material 50 described above are prepared (see FIG. 4A). Next, the film-like circuit connection material 50 is placed on the surface (main surface 21a) on which the electrode 22 of the circuit member 20 is formed. For example, when the film-like circuit connecting material 50 is formed on a support (not shown), the film-like circuit connecting material 50 side is directed to the circuit member 20 so that the circuit member 20 is placed on the circuit member 20. Placed on. At this time, since the circuit connection material 50 is in the form of a film, it is easy to handle. Therefore, the circuit connection material 50 can be easily interposed between the circuit member 20 and the circuit member 30, and the connection work between the circuit member 20 and the circuit member 30 can be easily performed.

  Then, the circuit connecting material 50 is pressurized in the direction of arrow A in FIG. 4A and the circuit member 20 is pressed in the direction of arrow B, respectively, so that the circuit connecting material 50 is temporarily connected to the circuit member 20 (FIG. 4B). )reference). This temporary connection may be performed by applying pressure while heating. However, the heating temperature is set to a temperature at which the adhesive composition in the circuit connecting material 50 is not cured, for example, a temperature lower than the temperature at which the radical polymerization initiator generates radicals.

  Subsequently, as shown in FIG. 4C, the circuit member 30 is placed on the circuit connection material 50 so that the electrode 32 faces the circuit member 20. For example, when the circuit connection material 50 has a support (not shown) on the side opposite to the circuit member 20, the circuit member 30 is placed on the circuit connection material 50 after the support is peeled off. .

Then, the circuit connection material 50 is heated by, for example, a heating head or the like, and the circuit members 20 and 30 are pressurized in the directions of arrows A and B in FIG. The heating temperature at the time of this connection is a temperature at which the low melting point metal that is the main component of the conductive layer 14 of the conductive particles 10 can be melted and the temperature at which the radical polymerization initiator can generate radicals. As conditions for this connection, the heating temperature can be 130 to 250 ° C., and the connection time can be 1 to 60 seconds. Thus, first, when it reaches the temperature near the softening point T _4, the adhesive composition 52 to flow. Then, in the vicinity of the softening point T _3, the insulating layer 16 of the conductive particles 10 exhibits a fluidity softened. When the circuit members 20 and 30 are respectively pressed in the A direction and the B direction, the adhesive composition 52 and the insulating layer 16 start to flow in this order, and the surface of the conductive particles has a low melting point metal as a main component. Layer 14 is exposed. That is, the insulating layer 16 softens and is pressed by the first and second electrodes 22 and 32, so that the insulating layer 16 flows, and the surface 14 a of the conductive layer 14 is selectively applied to the pressed portion of the conductive particles 10. (FIG. 2) is exposed.

When the temperature is further increased, the conductive layer 14 in the vicinity of the melting point T ₂ of the low melting point metal melts. By this melting, the first electrode 22 and the second electrode 32 are joined via the low melting point metal. In some cases, such joining is performed by joining low melting point metals of a plurality of conductive particles between the first electrode 22 and the second electrode 32. At the same time, the conductive layer 14 flows by being pressed by the electrodes 22 and 32, and the surface 12 a (FIG. 2) of the core 12 is selectively exposed at the pressed portion of the conductive particles 10. As a result, the electrodes 22 and 32 and the core 12 of the conductive particles are in direct contact. That is, the first electrode 22 and the second electrode 32 are connected via the low melting point metal part 114 and the core 12.

  Further, in the adhesive composition 52, the radical polymerization initiator generates radicals and the polymerization of the radical polymerizable compound is started. In this way, the adhesive composition of the circuit connecting material 50 is cured, and the main connection is performed. As a result, a circuit member connection structure 24 as shown in FIG. 3 is obtained. The conditions for this connection can be appropriately selected according to the composition of the adhesive composition, the material of the circuit member, the use of the connection structure, and the like. Moreover, you may post-cure after this connection as needed.

  Since the conductive particle 10 includes the core 12, it is difficult to be completely crushed between the first electrode 22 and the second electrode 32. Therefore, since it can suppress that the molten low melting metal spreads in the direction orthogonal to a pressurization direction, joining between the some electrically-conductive particle 10 in the direction can be prevented. Further, since the portion other than the exposed portion on the surface 14a (FIG. 2) of the conductive layer 14 is covered with the insulating layer 16, the electricity between the plurality of conductive particles 10 in the direction orthogonal to the pressing direction. Can be prevented.

  When the circuit member connection structure 24 is manufactured as described above, the connection resistance between the first electrode 22 and the second electrode 32 facing each other can be sufficiently reduced, and the electrodes adjacent to each other on the same substrate. The insulation between the electrodes 22 and the electrodes 32 can be sufficiently improved.

  The connection structure obtained by the main connection described above has the insulating portion 11 in which the adhesive composition is cured in a state where the distance between the electrode 22 and the electrode 32 is sufficiently small (FIG. 3). Moreover, since the conductive layer 14 is solidified after being melted and bonded to the electrode 22 and the electrode 32, the circuit member 20 and the circuit member 30 are firmly connected via the circuit connection portion 26. In the obtained circuit member connection structure 24, the circuit connection portion 26 is made of a cured product of the circuit connection material. Therefore, the circuit connection portion 26 is bonded to the first circuit member 20 and the second circuit member 30. The strength is high enough.

  Since the conductive layer 14 is mainly composed of a low melting point metal, the process temperature when the circuit member connection structure 24 is manufactured can be lowered. Therefore, since the parts constituting the circuit member connection structure 24 are not required to have so much heat resistance, the material selection range of the parts can be sufficiently widened.

(Modification of connection structure)
FIG. 5 is a cross-sectional view schematically showing a semiconductor device which is an example of the connection structure of the present invention. The semiconductor device 100 includes a semiconductor element 80 and a substrate 60 that supports the semiconductor element 80. Between the semiconductor element 80 and the substrate 60, a semiconductor element connection member 40 (circuit connection portion) for electrically and mechanically connecting them is provided. The semiconductor element connection member 40 is provided on the main surface 60 a of the substrate 60. The semiconductor element 80 is provided on the semiconductor element connection member 40.

  A plurality of circuit patterns 61 are formed on the substrate 60. The circuit pattern 61 is disposed to face the semiconductor element 80. The semiconductor element connection member 40 is provided between the semiconductor element 80 and the substrate 60 and electrically and mechanically connects them.

  The constituent material of the semiconductor element 80 is not particularly limited, but is a group IV semiconductor material such as silicon or germanium, GaAs, InP, GaP, InGaAs, InGaAsP, AlGaAs, InAs, GaInP, AlInP, AlGaInP, GaNAs, GaNP, GaInNAs, III-V group compound semiconductor materials such as GaInNP, GaSb, InSb, GaN, AlN, InGaN, InNAsP, II-VI group compound semiconductor materials such as HgTe, HgCdTe, CdMnTe, CdS, CdSe, MgSe, MgS, ZnSe, and ZeTe, Various materials such as CuInSe (CIS) can be used.

  The semiconductor element connection member 40 is composed of a cured product of the circuit connection material of the above embodiment. Similar to the circuit connection portion 26, the semiconductor element connection member 40 includes, for example, the core 12, the low melting point metal portion 114 made of a material mainly composed of the low melting point metal that forms the conductive layer 14, and the insulating layer 16. The insulating resin part 116 which consists of a hardened | cured material of the resin composition to perform and the insulating part 11 which is a hardened | cured material of an adhesive composition are provided.

  In the semiconductor device 100, the semiconductor element 80 and the circuit pattern 61 are electrically connected via the low melting point metal part 114. For this reason, the connection resistance between the semiconductor element 80 and the circuit pattern 61 is sufficiently reduced. Therefore, the flow of current between the semiconductor element 80 and the circuit pattern 61 can be made smooth, and the functions of the semiconductor element 80 can be sufficiently exhibited. Moreover, since the semiconductor element connection member 40 has excellent anisotropic conductivity, the insulation between the adjacent circuit patterns 61 is sufficiently maintained. Therefore, occurrence of a short circuit between adjacent circuit patterns 61 can be sufficiently suppressed.

  In the semiconductor element connection member 40, the low melting point metal portion 114, the semiconductor element 80, and the circuit pattern 61 are metal-bonded, so that the bonding strength of the semiconductor element connection member 40 to the semiconductor element 80 and the substrate 60 is sufficiently high. This state can be maintained for a long time. Therefore, the long-term reliability of the electrical characteristics between the semiconductor element 80 and the substrate 60 can be sufficiently increased.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  For example, the film-like circuit connecting material 50 may have a multilayer structure (not shown) composed of two or more layers having a Tg (glass transition temperature) of 5 ° C. or more different when cured.

EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all. Each softening point below _{(T 1s, T 3, T} 4) , using a thermomechanical analyzer TMA / SS6000 manufactured by Seiko Instruments Inc., in the compression mode or a tensile mode, heating rate 5 ° C. Glass transition temperature measured in / min.

Example 1
(1) Preparation of conductive particles <Pretreatment>
Conivex C type (spherical phenol resin, average particle size: 5 μm, manufactured by Unitika Co., Ltd., softening point T _1s : 180 ° C.) is forcibly stirred in methyl alcohol to perform pre-treatment for degreasing and roughening. went. Thereafter, methyl alcohol was separated by filtration to obtain a pretreated polymer core material (core).

<Activation>
The obtained polymer core material was dispersed in Circuit Prep 3316 (PdCl ₂ + HCl + SnCl ₂ type activation treatment solution, trade name, manufactured by Nippon Electroplating Engineers Co., Ltd.) and stirred at 25 ° C. for 20 minutes. The activation process was performed. Subsequently, washing and filtration were performed to obtain a polymer core having an activated surface.

<Electroless Ni plating>
The obtained polymer core was immersed in a blue schema (electroless Ni plating solution, bath capacity of 300 μdm ² / l, product name, manufactured by Nippon Kanisen Co., Ltd.) and forcedly stirred at 90 ° C. for 30 minutes. Thereafter, it was washed with water to obtain Ni-coated particles in which the polymer core was coated with nickel plating.

<Electroless Au plating>
Substitution plating of Au was performed on the surface of the Ni-coated particles. As the plating solution, electroless prep (electroless Au plating solution, manufactured by Nippon Electroplating Engineers Co., Ltd., trade name) was used, and a plating treatment was performed at 90 ° C. for 30 minutes. Thereafter, it was thoroughly washed with water and dried at 90 ° C. for 2 hours to obtain Ni—Au coated particles. This Ni—Au coated particle was used as a core. The Ni—Au coated particles had a thin metal layer of Ni 0.3 μm / Au 0.05 μm. The thicknesses of the Ni plating and Au plating were calculated from scanning electron microscope images of the particle cross section. The metal foil layer has a melting point of 1000 ° C. or higher.

<Solder plating>
The surface of the obtained Ni—Au coated particles was subjected to eutectic solder plating (43% Sn-57% Bi, melting temperature (T ₂ ) 139 ° C.) using a barrel plating apparatus to obtain SnBi coated particles. . When the cut surface of the obtained SnBi-coated particles was observed with a scanning electron microscope (SEM), the thickness of the solder plating layer was 3 μm.

<Formation of insulating layer>
Conductive particles were produced by forming an insulating layer on the surface of the obtained SnBi-coated particles as follows. As a material for the insulating layer, a dimethylformamide (DMF) solution containing 1% by mass of paraprene P-25M (thermoplastic polyurethane resin, softening point T ₃ : 130 ° C., trade name, manufactured by Nippon Elastolan Co., Ltd.) was prepared. . To this solution, SnBi-coated particles were added and stirred. Then, spray drying was performed at 100 ° C. for 10 minutes using a spray dryer (trade name: GA-32 type, manufactured by Yamato Scientific Co., Ltd.) to obtain conductive particles. As a result of cross-sectional observation using a scanning electron microscope (SEM), the average thickness of the insulating layer of the conductive particles was about 1 μm.

(2) Production of circuit connection material A film-like circuit connection material was produced by the following procedure. First, 50 g of phenoxy resin (manufactured by Union Carbide Co., Ltd., trade name: PKHC, average molecular weight: 45,000), toluene (boiling point: 110.6 ° C., SP value: 8.90) / ethyl acetate (boiling point: 77.000). A phenoxy resin dispersion having a solid content of 40% by mass was prepared by dissolving in a mixed solvent of 1 ° C. and SP value of 9.10) = 50/50.

  As the radical polymerizable compound, hydroxyethyl glycol dimethacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: 80MFA) and phosphate ester dimethacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: P-2M) were prepared.

  As radical polymerization initiator, di-2-ethylhexyl peroxydicarbonate (manufactured by NOF Corporation, trade name: Parroyl OPP) was prepared.

Each material prepared as described above was blended in the following mass ratio in terms of solid content, and further, conductive particles prepared as described above were added and dispersed to obtain an adhesive liquid. The addition amount of the conductive particles was set to 3% by mass with respect to the entire circuit connection material obtained.
・ PKHC: 50
・ 80MFA: 50
・ P-2M: 10
・ Paroyle OPP: 5

  Next, the obtained adhesive solution is applied to a fluororesin film having a thickness of 80 μm using a coating apparatus, and dried with hot air at 70 ° C. for 10 minutes to obtain a film-like circuit connection material having a thickness of 20 μm. It was. The obtained film-like circuit connecting material showed sufficient flexibility at room temperature.

(3) Fabrication of connection structure Next, a flexible substrate (trade name: COF TEG_50A, manufactured by Hitachi Ultra LSI Systems Co., Ltd.) having an Au plating circuit with a line width of 25 μm, a pitch of 50 μm, and a thickness of 8 μm, and Au with a pitch of 50 μm A semiconductor element having a bump (bump size 30 μm × 100 μm) (manufactured by Hitachi Ultra LSI Systems Co., Ltd., trade name: JTEG Phase 6_50) was prepared. Between the flexible substrate and the semiconductor element, the film-like circuit connection material (untreated, width 2 mm) produced as described above is placed, and a thermocompression bonding apparatus (heating method: constant heat type, manufactured by Toray Engineering Co., Ltd.) It was used and heated and pressurized at 160 ° C. and 3 MPa for 15 seconds. The pressurization was performed in the direction in which the flexible substrate and the semiconductor element face each other. Thus, a circuit member connection structure (semiconductor element / flexible substrate connection structure) was produced.

(Example 2)
FR-4 substrate (Hitachi super LSI) having Au bumps with a pitch of 130 μm and semiconductor elements (Bump size: 70 μm × 70 μm) (manufactured by Hitachi Ultra LSI Systems, trade name: JTEG Phase 0-GB) and Au plating pads with a pitch of 130 μm The product made by Systems, brand name: JKIT Type II) was prepared. A film-like circuit connecting material (untreated, 2.5 mm × 2.5 mm) produced in the same manner as in Example 1 is placed between the FR-4 substrate and the semiconductor element, and a thermocompression bonding apparatus (heating method) : Constant heat type, manufactured by Toray Engineering Co., Ltd.) and heated and pressurized at 160 ° C. and 3 MPa for 15 seconds. Thus, a circuit member connection structure (semiconductor element / FR-4 substrate connection structure) was produced.

(Comparative Example 1)
Conductive particles were produced in the same manner as in Example 1 except that solder plating was not performed. As a result of cross-sectional observation with a scanning electron microscope (SEM), the average thickness of the insulating layer of the conductive particles was about 1 μm, the same as in Example 1. And the circuit connection material was produced like Example 1 using the said electroconductive particle, and the connection structure (semiconductor element / flexible substrate connection structure) was obtained.

(Comparative Example 2)
A circuit connection material was prepared in the same manner as in Example 2 except that the conductive particles prepared in Comparative Example 1 were used as the conductive particles, and a connection structure (semiconductor element / FR-4 substrate connection structure) was prepared. Obtained.

(Comparative Example 3)
Conductive particles were produced in the same manner as in Example 1 except that the insulating layer was not formed. In the same manner as in Example 1, a circuit connection material was produced to obtain a connection structure (semiconductor element / flexible substrate connection structure).

<Measurement of connection resistance>
The connection resistance between the circuit members facing each other in the connection structures produced in the above Examples and Comparative Examples was measured. Specifically, the connection resistance of the circuit in which all the electrodes of each connection structure were connected by a daisy chain was measured using a DIGITAL MULTITIMER R6871E manufactured by ADVANTEST. At this time, the measurement current was 1 mA. The measurement results were as shown in Table 1. In the case of using a circuit connecting material having a low melting point metal layer inside the conductive particles (Examples 1 and 2), the conduction is made only by contact of the high melting point metal (Au, Ni) without the low melting point metal layer. The connection resistance was lower than when the secured circuit connection material was used (Comparative Examples 1 and 2).

<Temperature cycle life>
The temperature resistance cycle life of the connection structures produced in the above examples and comparative examples was evaluated. The temperature range in the measurement was a lower limit of −40 ° C. and an upper limit of 125 ° C., and the holding time at the lower limit and the upper limit temperature was 15 minutes. A series of steps of heating from normal temperature to the upper temperature limit, cooling to the lower temperature limit, and then returning to the normal temperature was defined as one cycle, and this cycle was repeated to evaluate temperature cycle resistance. The evaluation was performed by taking out the connection structure from the temperature cycle test apparatus every 100 cycles, measuring the connection resistance, and measuring the number of cycles until an open defect occurred.

  The measurement results are as shown in Table 1. The connection structure (Examples 1 and 2) using the circuit connection material having the low melting point metal layer inside the conductive particles is conductive only by the contact of the high melting point metal (Au, Ni) without the low melting point metal layer. It was confirmed that the temperature cycle life was longer than that of the circuit connecting material (Comparative Examples 1 and 2) that ensured the above. When conductive particles having no insulating layer are used (Comparative Example 3), adjacent conductive particles are fused and adjacent electrodes are short-circuited when a connection structure is manufactured. (Short) occurred. For this reason, the temperature cycle resistance could not be evaluated.

It is sectional drawing which shows typically one suitable embodiment of the circuit connection material of this invention. It is sectional drawing which shows typically suitable one Embodiment of the electroconductive particle of this invention. It is sectional drawing which shows typically suitable one Embodiment of the connection structure of this invention. It is process sectional drawing which shows typically an example of the manufacturing method of the connection structure of this invention. It is sectional drawing which shows typically the semiconductor device which is an example of the connection structure of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Conductive particle, 11 ... Insulating part, 12 ... Core, 12a ... Surface of core, 14 ... Conductive layer, 14a ... Surface of conductive layer, 16 ... Insulating layer, 20 ... Circuit member (first circuit member), 21 ... Circuit board (first circuit board), 21a, 31a, 60a ... Main surface, 22 ... Electrode (first electrode), 24 ... Connection structure, 26 ... Circuit connection part, 30 ... Circuit member (second Circuit member), 31 ... circuit board (second circuit board), 32 ... electrode (second electrode), 50 ... circuit connecting material, 52 ... adhesive composition, 60 ... substrate, 61 ... circuit pattern, 40 ... Semiconductor element connecting part, 80... Semiconductor element, 100... Semiconductor device, 114 .low melting point metal part, 116.

Claims (5)

A circuit connection material for connecting a first electrode and a second electrode facing each other,
An adhesive composition, and conductive particles dispersed in the adhesive composition,
The adhesive composition contains a thermosetting resin ;
The conductive particles include a core mainly composed of a material having a melting point or softening point T ₁ (° C.) and a conductive material mainly composed of a low melting point metal having a melting point T ₂ (° C.) covering the surface of the core. And an insulating layer made of a resin composition having a softening point of T ₃ (° C.) that covers the surface of the conductive layer, and T ₁ , T _2, and T ₃ satisfy the following formula (1): And
The adhesive compositions are those having fluidity by heating, curing the low-melting-point metals and the first electrode and the second electrode from the junction with the conductive layer mainly Monodea Ru circuits connecting material.
T ₁ > T ₂ > T ₃ (1) A circuit connection material for connecting a first electrode and a second electrode facing each other,
An adhesive composition, and conductive particles dispersed in the adhesive composition,
The adhesive composition contains a thermoplastic resin ;
The conductive particles include a core mainly composed of a material having a melting point or softening point T ₁ (° C.) and a conductive material mainly composed of a low melting point metal having a melting point T ₂ (° C.) covering the surface of the core. And an insulating layer made of a resin composition having a softening point of T ₃ (° C.) that covers the surface of the conductive layer ,
The softening point of the adhesive composition when the _{T 4,} wherein _{T 1,} T 2, _{T 3} and _{T 4} are times satisfying the following formula (2) path connecting material.
T ₁ > T ₂ > T ₃ > T ₄ (2) The circuit connection material according to claim 1 or 2 , wherein the content of the conductive particles is 1 to 10% by mass. The circuit connection material according to any one of claims 1 to 3 , wherein the shape is a film. A first circuit member having a first circuit electrode formed on a main surface of a first substrate;
A second circuit member having a second circuit electrode formed on a main surface of the second substrate and disposed so that the second circuit electrode and the first circuit electrode face each other;
A connection structure provided between the first substrate and the second substrate, the circuit connection unit connecting the first circuit member and the second circuit member;
The said circuit connection part contains the hardened | cured material of the circuit connection material as described in any one of Claims 1-4 , and the said 1st circuit electrode and the said 2nd circuit electrode are the said conductive layers of the said electrically-conductive particle. A connection structure that is electrically connected via the low-melting-point metal contained in the structure.

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