KR20130018950A - Circuit connecting material and connection structure - Google Patents

Abstract

This invention is the circuit connection material 50 for connecting the 1st electrode and the 2nd electrode which oppose each other which have the adhesive composition 52 and the electrically-conductive particle 10 dispersed in the adhesive composition 52. The conductive particles 10 are composed of a core 12 composed mainly 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 12. And the insulating layer 16 which consists of a resin composition whose softening point is T <_3> (degreeC) covering the surface of the conductive layer 14 and the conductive layer 14 to be used, and T <_1> , T <_2> and T <_3> The following Equation 1 is satisfied.
&Quot; (1) &quot;
T ₁ > T ₂ > T ₃

Description

CIRCUIT CONNECTING MATERIAL AND CONNECTION STRUCTURE}

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

BACKGROUND OF THE INVENTION With the miniaturization and thinning of electronic components, the electrodes used in electronic components are becoming denser and highly precise. An anisotropic conductive adhesive or an anisotropic conductive film is used as a circuit connection material which connects the 1st electrode and the 2nd electrode which oppose. As such an anisotropic conductive film, what formed the circuit connection material containing a some electroconductive particle (for example, metal particles, such as Ni), and an adhesive composition in a film form is mentioned.

The opposingly arranged first electrode and the second electrode 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 disposed to face each other. Thereafter, the structure including 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 adhesively fixed to each other by curing the anisotropic conductive film. Thereby, the 1st electrode and the 2nd electrode which oppose are electrically connected, maintaining the insulation between adjacent 1st and 2nd electrode.

In the connection method mentioned above, the electrical conduction between the 1st electrode and the 2nd electrode which oppose is obtained mainly by the electrically-conductive particle in an anisotropically conductive film contacting 1st and 2nd electrode. However, in such a connection, since conduction is obtained by the contact of metals with high melting points, the contact resistance is large and the long-term connection reliability is insufficient.

 Therefore, as an attempt to reduce the contact resistance, for example, a plurality of different metal layers are provided on the surface of the substrate, and an indium, tin, tin-lead alloy having a low melting point as the outermost layer is proposed as a main component (examples). For example, refer patent document 1, 2). In this case, the outermost layer of the conductive particles is melted by heating, and the molten low-melting metal is metal-bonded with the first and second electrodes, so that the connection resistance between the first electrode and the second electrode disposed opposite to each other is reduced. Can be.

Japanese Patent Laid-Open No. 2002-170427 Japanese Patent No.3542611

However, in the case of using the conductive particles as in Patent Documents 1 and 2, since the low-melting-point metal on the surface has a very large surface tension in the molten state, adjacent conductive particles are adjacent to each other when heating and pressing to connect the electrodes. It is easy to fuse by contact. As a result, there exists a tendency for adjacent electrodes to conduct and short-circuit (short). This tendency becomes more pronounced as the pitch between adjacent first and second electrodes becomes narrower.

This invention is made | formed in view of the said situation, The connection which can maintain sufficient insulation and favorable electroconductivity for a long time, while being able to make sufficient insulation between adjacent electrodes on the same board | substrate and sufficient electroconductivity between the electrodes arrange | positioned opposing to high level. An object of the present invention is to provide a circuit connection material that is sufficiently excellent in reliability and conductive particles used in the circuit connection material. Moreover, by using the circuit connection material which has the said characteristic, it is an object to provide the connection structure with the sufficient insulation between the adjacent electrodes on the same board | substrate, and the electroconductivity between the electrodes arrange | positioned opposingly enough, and being excellent in connection reliability.

In order to achieve the above object, in the present invention, the main component is a core having 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. A conductive layer having a softening point T ₃ (° C.) and a conductive layer covering the surface of the conductive layer, wherein T ₁ , T _2, and T ₃ satisfy the following formula (1): To provide.

&Quot; (1) &quot;

T ₁ > T ₂ > T ₃

As for the electrically-conductive particle in this invention, the surface of the electrically conductive layer which has a low melting metal as a main component is also coat | covered with the insulating layer. Therefore, formation of the passivation film of the surface by exposure to an oxidizing atmosphere is fully 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 is softened to exhibit fluidity. As the insulating layer flows, a conductive layer mainly composed of low melting point metal is exposed on the surface of the conductive particles. When further heated to an elevated temperature, the conductive layer is melted at the melting point T ₂ of the low-melting metal. Since no passivation film is formed in the conductive layer of the conductive particles, the conductive layer melts smoothly not only inside the layer but also on its surface. For this reason, when used as a circuit connection material, for example, it becomes possible to fully adhere | attach with metallic materials, such as an electrode, rather than the electroconductive particle which does not have an insulating layer in outermost layer.

On the other hand, in the conventional conductive particles which do not have an insulating layer in the outermost layer, since the low melting point metal is generally poor in oxidation resistance, the conductive layer mainly containing the low melting point metal is easily oxidized. By doing so, it is considered that the surface of the oxidized conductive layer is stabilized by forming a so-called passivation film. In the conductive particles having such a conductive layer in the outermost layer, the non-oxidized low melting point metal inside the layer inside the passivation film is melted even when heated, and the stabilized passivation film on the surface is difficult to melt. For this reason, when used as a circuit connection material, for example, it is thought that it cannot come into close contact with an electrode sufficiently.

In the present invention, of the low melting point metal mainly composed of the conductive layer of the conductive particles, the melting point T ₂ is preferably 130 ℃ to 250 ℃.

Thereby, when a conductive particle is heated, a conductive layer can be melt | dissolved smoothly, for example, when it is used as a circuit connection material, the connection reliability of a connection structure can be improved further. On the contrary, if the melting point T ₂ of less than 130 ℃, for example, the upper limit in the temperature cycle test over 125 ℃, since the low melting point metal is molten, tend to be sufficiently excellent connection reliability, and sufficiently damage the excellent mechanical strength of the connection structure obtained There is this. On the other hand, if the melting point T ₂ exceeds 250 ℃, it does not have a low melting point metal at the time of connection of the electrode sufficiently melted, and there is a tendency that excellent conductive connection reliability, and the damage of the connecting element is obtained.

Moreover, this invention provides the circuit connection material containing an adhesive composition and the said electroconductive particle disperse | distributed in the said adhesive composition as a circuit connection material for connecting the 1st electrode and 2nd electrode which mutually oppose.

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

In addition, since the electrically-conductive particle in the circuit connection material of this invention has the insulating layer which has a resin composition whose surface tension is usually smaller than a low melting point metal as a main component in an outermost layer, in an adhesive composition at the time of heating and joining an electrode, The fusion of conductive particles can be sufficiently suppressed. For example, even if adjacent particles are in contact with each other, since they have an insulating layer on the outermost layer, they are not electrically conductive. For this reason, the insulation between adjacent electrodes on a same board | substrate can be maintained at a high level. In addition, although the insulating layer is in a molten or softened state at the time of pressurization at the time of electrode connection, since the external force due to pressurization does not directly act between the adjacent conductive particles in a direction perpendicular to the pressing direction, it breaks through the insulating layer. Therefore, it is considered that the possibility of contacting and fusion between the inner conductive layers is very low.

That is, the external force by the pressure at the time of electrode connection acts to flow or exclude the insulating layer which is in the molten or softened state with respect to the electrically-conductive particle clamped between the 1st and 2nd electrode opposingly arranged, and melt | dissolved It acts as a force for pressing the conductive layer onto the first or second electrode. However, in the conductive particles of the present invention, since a core mainly composed of a material having a high melting point or softening point T ₁ exists, the possibility of being crushed by an external force and scattering of the low melting point metal component to the surroundings is very low.

The circuit connecting material of the present invention, the adhesive composition containing a thermoplastic resin, the softening point of the adhesive composition when hayeoteul la T _4, it is preferable to satisfy the following expression (2).

&Quot; (2) &quot;

T ₁ > T ₂ > T ₃ > T ₄

This circuit connecting material has the adhesive composition has sufficient fluidity having a low softening point T ₄ at the time of connection of an electrode disposed opposite. For this reason, sufficient pressure is applied to the electrode and electroconductive particle arrange | positioned by heating and pressurization, and connection stability can be improved further. In addition, since the insulating layer of the conductive particles is mainly composed of a resin composition having a softening point T ₃ higher than T ₄ , the conductive particles are hardly fused even when they are in contact with each other when flowing, and do not participate in the connection between the electrodes arranged oppositely. the insulating layer of the conductive particles, because the main component a resin composition having a high softening temperature T ₃ than T _4, difficult to the exposed conductive layer of the conductive particles are not in contact with the electrode, a short circuit caused by contact between the conductive layer of the conductive particles Can be prevented even more reliably.

In the circuit connection material of the present invention, the adhesive composition contains a thermosetting resin, the adhesive composition has fluidity by heating, and the first electrode and the second electrode and the conductive layer composed mainly of the low melting point metal are bonded and cured. It is preferable.

That is, when the adhesive composition which comprises a circuit connection material contains a thermosetting resin, it is preferable that a viscosity falls by heating, has fluidity, and hardening reaction advances and thickens and becomes solid by continuing heating. When the temperature of a circuit connection material rises by heating and pressurization, a connection structure can be formed as demonstrated below. That is, the adhesive composition shows 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 metal is then melted to form a metal junction with the first and second electrodes. The viscosity of the adhesive composition is then increased to cure. In addition, since the pressure is not applied to the insulating layer of the conductive particles which is not involved in the connection between the electrodes arranged oppositely, even if the temperature is higher than the softening point T ₃ , the conductive layer of the conductive particles is difficult to be exposed, and the conductive layers of the conductive particles The occurrence of a short due to contact can be reliably prevented.

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

By using the circuit connection material whose content of electroconductive particle is 1-10 mass% of the whole circuit connection material, connection resistance of the mutually arrange | positioned electrodes is further made small enough, and insulation of adjacent electrodes on the same board | substrate is further improved. I can keep it enough.

It is preferable that the circuit connection material of this invention is formed in the film form. The circuit connection material which has such a shape can perform the process to which the opposingly arranged circuit electrode is connected very easily.

In the present invention, further, a first circuit member having a first circuit electrode formed on the main surface of the first substrate, a second circuit electrode formed on the main surface of the second substrate, and the second circuit electrode and the first circuit electrode facing each other. A connecting structure comprising a second circuit member disposed so as to be provided, and a circuit connecting portion provided between the first substrate and the second substrate and connecting the first circuit member and the second circuit member, wherein the circuit connecting portion is the circuit connecting material described above. It provides the bonded structure including the hardened | cured material of, and the 1st circuit electrode and the 2nd circuit electrode electrically connected through the low melting metal contained in the conductive layer of electroconductive particle.

Since this connection structure has a hardened | cured material which hardened the circuit connection material which has the above-mentioned characteristic in a circuit connection part, while being able to make both sufficient insulation between adjacent electrodes on the same board | substrate, and sufficient conductivity between the electrodes arrange | positioned opposing to high level, it is favorable. Insulation and good conductivity can be maintained for a long time.

According to the present invention, a circuit connection material excellent in connection reliability capable of maintaining good insulation and good conductivity for a long period of time while achieving sufficient insulation between adjacent electrodes and sufficient conductivity between adjacent electrodes on the same substrate at a high level can be obtained. Can provide. Moreover, the electroconductive particle suitable for using for such a circuit connection material can be provided. Moreover, by using the circuit connection material containing the electroconductive particle which has the said characteristic, sufficient insulation between the adjacent electrodes on the same board | substrate, and electroconductivity between the electrodes arrange | positioned opposingly are fully improved, and the connection structure excellent in connection reliability can be provided sufficiently. have.

1: is sectional drawing which shows typically one preferred embodiment of the circuit connection material of this invention.
It is sectional drawing which shows typically one preferred embodiment of the electroconductive particle of this invention.
It is sectional drawing which shows typically one Embodiment with preferable connection structure of this invention.
It is process sectional drawing which shows an example of the manufacturing method of the bonded structure of this invention typically.
It is sectional drawing which shows typically a semiconductor device which is an example of the bonded structure of this invention.
Description of the Related Art
10... Conductive particles, 11... Insulator, 12... Core, 12a... Surface of core, 14... Conductive layer, 14a... 16 surface of conductive layer; 20 insulating layer; Circuit member (first circuit member), 21... Circuit board (first circuit board), 21a, 31a, 60a... If you give, Electrode (first electrode), 24... Connection structure, 26... Circuit connection portion 30... Circuit member (second circuit member), 31... Circuit board (second circuit board), 32... Electrode (second electrode), 50... Circuit connection material, 52... Adhesive composition, 60... Substrate 61... Circuit pattern, 40... Semiconductor element connecting portion, 80... Semiconductor element, 100... Semiconductor device, 114... Low melting point metal portion, 116... Insulation resin part.

BEST MODE FOR CARRYING OUT THE INVENTION [

Preferred embodiments of the present invention will be described below.

(Circuit connection material)

1: is sectional drawing which shows typically one preferred embodiment of the circuit connection material of this invention. The circuit connection material 50 of FIG. 1 has a film shape. The circuit connection material having such a shape is unlikely to cause a problem of rupture, cracking or sticking, and is easy to handle. The film-form circuit connection material 50 has the adhesive composition 52 which is an insulation part, and the electroconductive particle 10 dispersed in the adhesive composition 52. As shown in FIG.

The film-form circuit connection material 50 melt | dissolves an adhesive composition in a solvent, for example, and the thing which electroconductive particle 10 was disperse | distributed using a conventional coating apparatus on a support body (PET (polyethylene terephthalate) film etc.) It can apply | coat and manufacture by hot-air drying for a predetermined time at the temperature which an adhesive composition does not harden.

It is preferable that the thickness of the film-form circuit connection material 50 is 10-50 micrometers. When the thickness of the film-form circuit connection material 50 is 10 micrometers or more, a sufficient amount of circuit connection material can be filled between opposing circuit members, and there exists a tendency which can fully maintain the insulation between adjacent electrodes on the same board | substrate. have. Moreover, when the said thickness is 50 micrometers or less, the adhesive composition between the electrodes arrange | positioned opposing at the time of connection can fully be excluded, and it exists in the tendency which becomes easy to ensure the conduction between opposing electrodes.

It is preferable that content of the electroconductive particle 10 with respect to the gross mass of the circuit connection material 50 is 1-10 mass%. When the said content rate is 1 mass% or more, there exists a tendency for the electroconductivity between the opposing electrodes after connection structure formation to improve further. On the other hand, when the said content rate is 10 mass% or less, there exists a tendency which can improve the insulation between the circuit electrodes adjacent on the same board | substrate further.

It is preferable that the average particle diameter of the electroconductive particle 10 is 1-10 micrometers. If the average particle diameter of the electrically-conductive particle 10 is 1 micrometer or more, it exists in the tendency for a more favorable connection state to be easy to be obtained by absorbing the unevenness | corrugation of an electrode surface and the height fluctuation between electrodes. On the other hand, when the average particle diameter of the electrically-conductive particle 10 is 10 micrometers or less, there exists a tendency for the adjacent electrodes to short-circuit on the same board | substrate even if it becomes narrow pitch between electrodes.

The conductive particles 10 may be mixed with a plurality of ones having the same shape, the same dimensions, and the same material, or may be mixed with a plurality of different shapes, different dimensions, and different materials. In this embodiment, it is also possible to disperse the conductive particles 10 in the adhesive composition 52 by combining, for example, conventional conductive particles. As a conventional electrically-conductive particle, what consists of metals, such as Au, Ag, Ni, Cu, Co, solder, carbon, etc. is mentioned, for example. Moreover, what coat | covered nonelectroconductive glass, ceramic, a plastic, etc. with electrically conductive materials, such as the said metal, can also be used as a conventional electrically-conductive particle. At this time, it is preferable that the thickness of the metal layer to coat | cover is 0.1 micrometer or more in order to acquire sufficient electroconductivity.

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

The form of a circuit connection material is not specifically limited, For example, the paste form which disperse | distributed the electroconductive particle 10 by adding organic solvent, such as toluene and ethyl acetate, to each component in the said adhesive composition 52 may be sufficient.

(Conductive particles)

It is sectional drawing which shows typically one preferred embodiment of the electroconductive particle of this invention. The conductive particles 10 of FIG. 2 include a core 12, a conductive layer 14 covering the surface 12a of the core, and an insulating layer 16 covering the surface 14a of the conductive layer 14. ). The shape of the electroconductive particle 10 is not specifically limited, For example, it may be substantially spherical. Such conductive particles 10 are preferably used as conductive particles for a circuit connection material.

The "conductive particle" in this specification may not show electroconductivity in the state of the particle | grain, and may show electroconductivity by melting or softening the insulating layer of a surface.

The conductive layer 14 is mainly composed of 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 that is 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 or the softening point T _1s of the material which is the main component of the core 12 are at a temperature higher than the melting point T ₂ of the low melting point metal. Further, in this specification, T ₁ is the melting point or softening point T represents a T _{1m 1s.} When the material that is the main component of the core 12 does not exhibit a clear melting point (amorphous or the like), T ₁ in the above formula (1) represents a softening point. Further, the resin composition constituting the insulating layer 16 have a lower softening point than the melting point T ₂ T _3.

Since the conductive particles 10 are covered with the insulating layer 16 on the surface 14a of the conductive layer 14, even if the conductive particles 10 are exposed to an oxidizing atmosphere, a passivation film is formed on the surface 14a. Is sufficiently suppressed. For this reason, the melting point T ₂ of the low melting point metal is followed by the softening of the insulating layer 16 and the exposure of the conductive layer 14 due to flow during heating when the opposing electrodes are connected. In the vicinity, the conductive layer 14 is melted. At this time, since the conductive layer 14 melt | dissolves not only the inside of a layer but its surface 14a easily, it becomes possible to make the electrically-conductive particle 10 closely contact with an electrode.

The conductive layer 14 of the conductive particles 10 exhibits electrical conductivity. That the main component of the conductive layer 14, the melting point metal preferably has a melting point T ₂ of 130 to 250 ℃. As such a low melting point metal, various process alloys, an unprocessed low melting point alloy, or a single metal are mentioned, for example. 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 degreeC), In (melting point 157 degreeC), etc. are mentioned.

The melting point of the low melting point metal T ₂ is more preferably from 150 to 200 ℃. Thereby, heating temperature at the time of the connection of the opposingly arrange | positioned circuit member can be made low, raising the material selection freedom degree of the resin composition and adhesive composition of the insulating layer mentioned later. Thus, the thermal effect of the connecting structure can be reduced.

* It is preferable that the thickness of the conductive layer 14 is 0.1-1 micrometer. When the thickness of the conductive layer 14 is 0.1 μm or more, for example, there is a tendency that 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 can be further expanded. On the other hand, if the thickness of the conductive layer 14 is 1 μm or less, even if electrodes of narrow pitch are connected to each other using the conductive particles 10, for example, short circuits between adjacent electrodes on the same substrate can be suppressed more reliably. Tend to be.

If the thickness of the conductive layer 14 is less than 0.1 µm, the contact area with the electrode to be connected to the conductive particles 10 is small, so that the effect of sufficiently reducing the connection resistance tends to be difficult to be obtained. On the other hand, when the thickness of the conductive layer 14 exceeds 1 micrometer, when the electrodes of narrow pitch are connected, for example using this electroconductive particle 10, a conductive layer will become too wide in the direction orthogonal to a pressurization direction. Since it is easy to carry, there exists a tendency for the short circuit between adjacent electrodes on the same board | substrate to increase.

In addition, the thickness of each layer which comprises the electrically-conductive particle 10 can be calculated | required as average thickness of each layer at the time of cut | disconnecting to the plane through the center of the electrically-conductive particle 10. FIG. This thickness can be confirmed, for example by 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 that is higher than the melting point T ₂ of the low melting point metal, which is the main component of the conductive layer 14. As the T _1m, preferably a T ₂ T ₂ +20 to +2000 ℃. Further, as the T _1s, preferably a T ₂ T ₂ +20 to +2000 ℃. The material of the core 12 may be an insulating material or 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 resins, 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 electrically-conductive particle 10 in the adhesive composition 52 can be made further more favorable.

On the other hand, by using the conductive material as the main component of the core 12, the core 12 can also pass current, so that the conductivity of the entire conductive particles 10 can be further improved. As a preferable electroconductive material, metals, such as Au, Ag, Ni, Cu, Co, solder, carbon, etc. are mentioned, for example. At least one of the melting point T _1m and the softening point T _1s may be used as the core 12 having a non-conductive glass, ceramic, plastic, or the like coated with a metal layer such as the metal, which is higher than the melting point T ₂ of the low melting point metal. At this time, it is preferable that the thickness of the metal layer which coat | covers a nonelectroconductive material is 0.1 micrometer or more from a viewpoint of obtaining sufficient electroconductivity.

In addition, the "softening point" in this specification means a bicat softening temperature or a glass transition temperature. Vicat softening temperature is the temperature at which the temperature of the bath is raised in a state in which a test piece having a prescribed size is placed in a heating bath, the end face of a predetermined cross-sectional area is pushed to the center, and the end face is eroded to a certain depth to the test piece. (JIS K7206). The glass transition temperature is the peak temperature of the loss tangent (tanδ) 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, almost 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. As such a resin composition, what contains a thermoplastic resin and / or hot melt resin is preferable. Moreover, the base polymer or elastomer of a hot melt adhesive which has thermosoftening property or melting | fusing point can also be used preferably. As such resin, for example, polyethylene, ethylene copolymer polymer, ethylene-vinyl acetate copolymer, polypropylene, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, polyamide, polyester, styrene-isoprene copolymer, styrene -Divinylbenzene copolymer, ethylene-propylene copolymer, acrylic ester rubber, polyvinyl acetal, acrylonitrile-butadiene copolymer, styrene, phenoxy, solid epoxy resin, polyurethane, etc .; Natural and synthetic resins, such as resin and rosin, and chelating agents, such as EDTA, are mentioned. These resin can also be used individually by 1 type or in combination of 2 or more type.

The insulating resin composition of the softening temperature T ₃ of the layer 16 is preferably from 130 to 250 ℃.

It is preferable that the thickness of the insulating layer 16 is 0.01-0.5 micrometer. When the thickness of the insulating layer 16 is 0.01 μm or more, the molten low melting point metal of the conductive layer 14 is disposed between the plurality of conductive particles 10 arranged in a direction orthogonal to the pressing direction (the direction in which the electrodes oppose). The joining of 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 conductive layer 14 is pressed against the pressed portion of the conductive particles 10 even at a small pressure. Since the surface 14a is exposed, the electroconductivity between opposing electrodes can be improved further.

(Adhesive composition)

The adhesive composition 52 contained in the circuit connection material 50 of this embodiment contains a radically polymerizable compound and a radical polymerization initiator.

A radically polymerizable compound is a compound which has a functional group superposed | polymerized by a radical. As a radically polymerizable compound, a (meth) acrylate compound, a maleimide compound, a citraconimide compound, a nadiimide compound, etc. are mentioned. These can also be used individually by 1 type or in mixture of 2 or more types. In addition, the radically polymerizable compound can be used in any state of a monomer or an oligomer, and can also be used in combination of a monomer and an oligomer.

As a (meth) acrylate compound, 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 tetra (meth) acrylate, 2-hydroxy-1,3-diacryloxypropane, 2,2-bis [4- ( Acryloxymethoxy) phenyl] propane, 2,2-bis [4- (acryloxyethoxy) phenyl] propane, dicyclopentenyl (meth) acrylate tricyclodecanyl (meth) acrylate, tris (acryloxy Ethyl) isocyanurate, urethane (meth) acrylate, isocyanuric acid ethylene oxide modified diacrylate, and the like. These can also be used individually by 1 type or in mixture of 2 or more types. A (meth) acrylic resin is obtained by radically polymerizing the said (meth) acrylate compound.

The maleimide compound is a compound having at least one maleimide group. Examples of the maleimide compound include phenyl maleimide, 1-methyl-2,4-bismaleimide benzene, N, N'-m-phenylene bismaleimide, N, N'-p-phenylene bismaleimide, N, N'-4,4-biphenylenebismaleimide, N, N'-4,4- (3,3-dimethylbiphenylene) bismaleimide, N, N'-4,4- (3,3 -Dimethyldiphenylmethane) bismaleimide, N, N'-4,4- (3,3-diethyldiphenylmethane) bismaleimide, N, N'-4,4-diphenylmethanebismaleimide, N, N'-4,4-diphenylpropanebismaleimide, N, N'-4,4-diphenyletherbismaleimide, N, N'-4,4-diphenylsulfonbismaleimide, 2, 2-bis (4- (4-maleimidephenoxy) phenyl) propane, 2,2-bis (3-s-butyl-3,4- (4-maleimidephenoxy) phenyl) propane, 1,1- Bis (4- (4-maleimidephenoxy) phenyl) decane, 4,4'-cyclohexylidene-bis (1- (4-maleimidephenoxy) phenoxy) -2-cyclohexylbenzene, 2, 2-bis (4- (4-maleimide phenoxy) phenyl) hexafluoro propane etc. are mentioned. These can also be used individually by 1 type or in combination of 2 or more type.

The citraconimide compound is a compound having at least one citraconimide group. Examples of the citraconimide compound include phenylcytraconimide, 1-methyl-2,4-biscitraconimidebenzene, N, N'-m-phenylenebiscitraconimide, and N, N'-p- Phenylenebiscitraconimide, N, N'-4,4-biphenylenebiscitraconimide, N, N'-4,4- (3,3-dimethylbiphenylene) biscitraconimide , N, N'-4,4- (3,3-dimethyldiphenylmethane) biscitraconimide, N, N'-4,4- (3,3-diethyldiphenylmethane) biscitracone Mead, N, N'-4,4-diphenylmethanebiscitraconimide, N, N'-4,4-diphenylpropanebiscitraconimide, N, N'-4,4-diphenylether Biscitraconimide, N, N'-4,4-diphenylsulfonbisbistraconimide, 2,2-bis (4- (4-citraconimidephenoxy) phenyl) propane, 2,2- Bis (3-s-butyl-3,4- (4-citraconimidephenoxy) phenyl) propane, 1,1-bis (4- (4-citraconimidephenoxy) phenyl) decane, 4, 4'-cyclohexylidene-bis (1- (4-citraconimidephenoxy) phenoxy) -2-cyclohexylbenzene, 2,2-bis ( 4- (4-citraconimide phenoxy) phenyl) hexafluoro propane etc. are mentioned. These can also be used individually by 1 type or in combination of 2 or more type.

* Nadiimide compound is a compound which has at least 1 nadiimide group. Examples of the nadiimide compound include phenylnamidide, 1-methyl-2,4-bisnamidimidebenzene, N, N'-m-phenylenebisnamidimide, N, N'-p-phenylenebisnamidimide, N, N'-4,4-biphenylenebisnamidimide, N, N'-4,4- (3,3-dimethylbiphenylene) bisnamidimide, N, N'-4,4- (3,3 -Dimethyldiphenylmethane) bisnamidimide, N, N'-4,4- (3,3-diethyldiphenylmethane) bisnamidimide, N, N'-4,4-diphenylmethanebisnamidimide, N, N'-4,4-diphenylpropanebisnamidimide, N, N'-4,4-diphenyletherbisnamidimide, N, N'-4,4-diphenylsulfonbisnamidimide, 2, 2-bis (4- (4-diimidephenoxy) phenyl) propane, 2,2-bis (3-s-butyl-3,4- (4-namidimidephenoxy) phenyl) propane, 1,1- Bis (4- (4-nadiimidphenoxy) phenyl) decane, 4,4'-cyclohexylidene-bis (1- (4-nadiimidphenoxy) phenoxy) -2-cyclohexylbenzene, 2, 2-bis (4- (4-nadiimidphenoxy) phenyl) hexafluoropropane etc. are mentioned. These can also be used individually by 1 type or in combination of 2 or more type.

Moreover, as a radically polymerizable compound, the radically polymerizable compound which has a phosphate ester structure can also be used.

The radically polymerizable compound which has a phosphate ester structure is used preferably from a viewpoint of improving the adhesive force of the adhesive composition with respect to inorganic substances, such as a metal. It is preferable that the usage-amount of the radically polymerizable compound which has a phosphate ester structure is 0.1-30 mass parts with respect to 100 mass parts of total solids of the adhesive composition 52, It is more preferable that it is 0.5-10 mass parts, It is 0.5-5 mass parts More preferred. A radically polymerizable compound having a phosphate ester structure is obtained as a reaction product of phosphoric anhydride and 2-hydroxyethyl (meth) acrylate. Specifically, mono (2-methacryloyloxyethyl) acid phosphate, di (2-methacryloyloxyethyl) acid phosphate (phosphate ester dimethacrylate), etc. are mentioned. These can also be used individually by 1 type or in mixture of 2 or more types.

As a radically polymerizable compound, it is preferable to use combining the (meth) acrylate compound and the radically polymerizable compound which has a phosphate ester structure. When using such a combination, compared with the case where the (meth) acrylate compound and the radically polymerizable compound which has a phosphate ester structure are respectively used independently, the adhesive strength of an adhesive composition can be improved more.

The radical polymerization initiator is not particularly limited as long as it is a compound which generates radicals by light irradiation and / or heating. As such a radical polymerization initiator, the compound which generate | occur | produces a radical by light irradiation of 150-750 nm and / or heating of 80-200 degreeC is preferable, and a peroxide, an azo compound, etc. are specifically preferable. These are appropriately selected in consideration of the target connection temperature, connection time, storage stability, and the like.

As a peroxide, organic peroxide is preferable from a viewpoint of high reactivity and storage stability. Of the organic peroxides, organic peroxides having a temperature of 10 hours for half-life (that is, the temperature at which the half-life becomes 10 hours) of 40 ° C. or more and a temperature of 1 minute for half-life (that is, the temperature at which the half-life is 1 minute) are 180 ° C. or less are preferable. The organic peroxide having a half-life of 10 hours at 50 ° C or more and a half-life of 1 minute at 170 ° C or less is more preferable. In addition, when making connection time into 10 second or less, from the viewpoint of obtaining a sufficient reaction rate, it is preferable that the compounding quantity of a radical polymerization initiator is 1-20 mass% on the basis of the solid content whole quantity of the adhesive composition 52, 2 It is especially preferable that it is 15 mass%.

Specific examples of the organic peroxide include diacyl peroxide, peroxydicarbonate, peroxy ester, peroxy ketal, dialkyl peroxide, hydroperoxide and silyl peroxide. Especially, peroxy ester, dialkyl peroxide, hydroperoxide, and silyl peroxide have the content of chlorine ion and organic acid reduced to 5000 ppm or less normally. For this reason, since there are few organic acids which generate | occur | produce after heat decomposition, and electrode corrosion of a circuit member can be suppressed, it is used especially preferably.

As the diacyl peroxide, isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinct Nickel peroxide, benzoyl peroxy toluene, benzoyl peroxide, etc. are mentioned.

As peroxydicarbonate, di-n-propyl peroxy dicarbonate, diisopropyl peroxy dicarbonate, bis (4-t- butylcyclohexyl) peroxy dicarbonate, di-2-ethoxy methoxy Ciperoxydicarbonate, di (2-ethylhexylperoxy) dicarbonate, dimethoxybutylperoxydicarbonate, di (3-methyl-3-methoxybutylperoxy) dicarbonate, and the like. .

As peroxy ester, cumyl peroxy neodecanoate, 1,1,3,3- tetramethylbutyl peroxy neodecanoate, 1-cyclohexyl-1-methylethyl peroxy neodecanoate, t-hex Silperoxyneodecanoate, t-butylperoxy pivalate, 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-ethylhexa Nonate, t-butylperoxyisobutyrate, 1,1-bis (t-butylperoxy) cyclohexane, t-hexylperoxyisopropyl monocarbonate, t-butylperoxy-3,5,5- Trimethylhexanoate, t-butylperoxylaurate, 2,5-dimethyl-2,5-di (m-toluylperoxy) hexane, t-butylperoxyisopropylmonocarbonate, t-butylper To oxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzo Y, t-butyl peroxy acetate, etc. are mentioned.

As peroxy ketal, 1, 1-bis (t-hexyl peroxy) -3, 3, 5- trimethyl cyclohexane, 1, 1-bis (t-hexyl peroxy) 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.

As dialkyl peroxide, (alpha), (alpha) '-bis (t-butyl peroxy) diisopropyl benzene, dicumyl peroxide, 2, 5- dimethyl- 2, 5- di (t-butyl peroxy) hexane, t -Butyl cumyl peroxide, etc. are mentioned.

Examples of the hydroperoxide include diisopropylbenzenehydroperoxide and cumene hydroperoxide.

* As silyl peroxide, t-butyl trimethyl silyl peroxide, bis (t-butyl) dimethyl silyl peroxide, t-butyl trivinyl silyl peroxide, bis (t-butyl) divinyl silyl peroxide, tris (t- Butyl) vinyl silyl peroxide, t-butyl triallyl silyl peroxide, bis (t-butyl) diallyl silyl peroxide, tris (t-butyl) allyl silyl peroxide, etc. are mentioned.

These radical polymerization initiators can be used individually by 1 type or in combination of 2 or more types, and can also be used in combination of a decomposition accelerator, an inhibitor, etc.

Moreover, what coat | covered these radical polymerization initiators with the polyurethane-type, polyester-type high molecular substance, etc., and microencapsulates can use it suitably because it can prolong pot life. Moreover, in addition to the radical polymerization initiator which generate | occur | produces a radical by heating or light irradiation, you may use the radical polymerization initiator which generate | occur | produces a radical by an ultrasonic wave, an electromagnetic wave, etc. as needed. Moreover, in order to suppress electrode corrosion of a circuit member, it is preferable that the density | concentration of the chlorine ion and organic acid contained in a radical polymerization initiator is 5000 ppm or less. Moreover, the radical polymerization initiator with few organic acids generated after thermal decomposition is more preferable. Moreover, since stability after hardening of an adhesive composition improves, it is preferable to have a mass retention of 20 mass% or more after 24 hours of open standing at room temperature and normal pressure.

In addition, the adhesive composition 52 may also contain radical polymerization inhibitors, such as hydroquinone and methyl ether hydroquinone, as needed in the range which does not impair sclerosis | hardenability.

The adhesive composition 52 may contain thermosetting resins other than a radically polymerizable compound. An epoxy resin is mentioned as such a thermosetting resin. As an epoxy resin, bisphenol A epoxy resin, bisphenol F-type epoxy resin, bisphenol S-type epoxy resin, phenol novolak-type epoxy resin, cresol novolak-type epoxy resin, bisphenol A novolak-type epoxy resin, bisphenol F novolak-type epoxy Resin, alicyclic epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, aliphatic chain epoxy resin and the like. These epoxy resins may be halogenated or hydrogenated. These epoxy resins can also be used individually by 1 type or in combination of 2 or more type.

Moreover, as a hardening | curing agent of the said epoxy resin, what is used as a hardening | curing agent of a normal epoxy resin can be used. Specific examples include amines, phenols, acid anhydrides, imidazoles, and dicyandiamide. Moreover, the tertiary amines and organophosphorus compounds which are normally used as a hardening accelerator can also be used suitably.

Moreover, as a method of making an epoxy resin react, in addition to using the said hardening | curing agent, it can also carry out cation polymerization using a sulfonium salt, an iodonium salt, etc.

The adhesive composition 52 may comprise a thermoplastic resin. As the thermoplastic resin, for example, polyethylene, ethylene copolymer polymer, ethylene-vinyl acetate copolymer, polypropylene, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, polyamide, polyester, styrene-isoprene copolymer, styrene -Divinylbenzene copolymer, ethylene-propylene copolymer, acrylic ester rubber, polyvinyl acetal, acrylonitrile-butadiene copolymer, etc. are mentioned. These resin can also be used individually by 1 type or in combination of 2 or more type. The softening point T ₄ of the adhesive composition 52 can be adjusted by adjustment of the kind and compounding ratio of a thermoplastic resin.

The adhesive composition 52 may contain a high molecular compound in order to provide film formability, adhesiveness, and stress relaxation property at the time of hardening. Examples of the polymer compound include polyvinyl butyral resin, polyvinyl formal resin, polyester resin, polyamide resin, polyimide resin, xylene resin, phenoxy resin, polyurethane resin, and urea resin.

It is preferable that the high molecular compound contained in the adhesive composition 52 has a molecular weight of 10,000-10,000,000. In addition, the polymer compound is preferably modified with a radical polymerizable functional group from the viewpoint of improving the heat resistance of the circuit connection material. In addition, these high molecular compounds may contain a carboxyl group. It is preferable that content of the said high molecular compound in the adhesive composition 52 is 2-80 mass% on the basis of solid content whole quantity of the adhesive composition 52, It is more preferable that it is 5-70 mass%, It is 10- It is more preferable that it is 60 mass%. When content of a high molecular compound is 2 mass% or more, there exists a tendency which can improve stress relaxation and adhesive force further. On the other hand, when content of a high molecular compound is 80 mass% or less, there exists a tendency which can fully suppress the fluidity | liquidity fall of an adhesive composition.

The adhesive composition 52 may suitably include fillers, softeners, accelerators, anti-aging agents, colorants, flame retardants, coupling agents.

In the adhesive composition 52 demonstrated above, it is preferable to contain 0.5-30 mass parts of radical polymerization initiators with respect to 100 mass parts of radically polymerizable compounds, and it is more preferable to contain 1.0-10 mass parts. When content of a radical polymerization initiator is 0.5 mass part or more, hardening reaction fully advances and there exists a tendency for hardening to become more sufficient. On the other hand, when content of a radical polymerization initiator is 30 mass parts or less, there exists a tendency for adhesive composition to have more excellent storage stability.

In the embodiment, a softening point T ₄ of the adhesive composition 52 is preferred to satisfy the equation (2). If the 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, the adhesive composition easily flows when connecting the circuit members arranged opposite to each other. The electrodes can be easily electrically connected. As the softening temperature T ₄ of the adhesive composition 52, it is preferable from the viewpoint of both a good fluidity and dimensional stability of the circuit connecting material of the adhesive composition 52 at the time of connection, the 130 to 150 ℃.

(Connection structure of a circuit member)

It is sectional drawing which shows typically one Embodiment with preferable connection structure of this invention. The connection structure 24 shown in FIG. 3 has the 1st circuit member 20 in which the some 1st electrode 22 was formed on the main surface 21a of the 1st circuit board 21, and the 2nd circuit board ( Between the second circuit member 30 having a plurality of second electrodes 32 formed on the main surface 31a of the 31, and between the main surface 21a of the circuit board 21 and the main surface 31a of the circuit board 31. The circuit connection part 26 provided in this is provided. In addition, 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 in some cases.

The circuit members 20 and 30 are not particularly limited as long as an electrode that requires electrical connection is formed. Specifically, glass or plastic board | substrate with which an electrode was formed in ITO etc. used for a liquid crystal display, a printed wiring board, a ceramic wiring board, a flexible wiring board, a semiconductor silicon chip, etc. are mentioned. These can be used in combination as needed. As described above, in the present embodiment, metals such as copper and aluminum, ITO (indium tin oxide), silicon nitride (SiNx), and silicon dioxide (SiO ₂ ), as well as materials made of organic materials such as printed wiring boards and polyimides, are used. Circuit members having various surface states can be used, such as inorganic materials such as).

The circuit connection part 26 connects the circuit member 20 and the circuit member 30 in the state which the circuit electrodes 22 and 32 oppose, and contains the hardened | cured material of the circuit connection material mentioned above. That is, the circuit connection part 26 comprises the core 12, the low-melting-point metal part 114 which consists of the material which has the low-melting-point metal as the main component which comprises the conductive layer 14, and the insulating layer 16. As shown in FIG. The insulating resin part 116 which consists of hardened | cured material of the resin composition being made, the insulating part 11 which consists of hardened | cured material of an adhesive composition, and the electroconductive particle 10 are provided.

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 portion 114 is bonded to the electrode 22 and the electrode 32 after the conductive layer 14 is melted and solidified. For this reason, the low melting metal part 114 is in close contact with the electrode 22 and the electrode 32. Therefore, while the connection resistance between the electrode 22 and the electrode 32 is sufficiently reduced, the electrode 22 and the electrode 32 can be firmly fixed. As a result, the current flows between the electrode 22 and the electrode 32 can be made smooth, and the function which a circuit has can fully be exhibited.

In addition, the electrode 22 and the electrode 32 can be more firmly fixed by the insulating resin portion 116. In addition, the insulated resin part 116 can suppress the conduction of the adjacent low melting metal parts 114 to each other. Therefore, the short circuit between adjacent 1st electrodes 22 (between 2nd electrodes 32) can fully be suppressed.

In this connection structure 24, the connection resistance between the opposing electrode 22 and the electrode 32 can be sufficiently reduced, and the insulating and adjacent second electrodes between the adjacent first electrodes 22 ( It is possible to sufficiently maintain the insulation between 32). In addition, the opposing electrode 22 and the electrode 32 are firmly fixed by the circuit connecting portion 26.

(Method of manufacturing a bonded structure)

Next, the manufacturing method of the connection structure 24 of the circuit member mentioned above is demonstrated, referring drawings. It is process sectional drawing which shows an example of the manufacturing method of the bonded structure of this invention typically. 4 (a) to 4 (c) are cross-sectional views schematically showing each step of the method for manufacturing a connection structure of a circuit member.

First, the circuit member 20 and the film-form circuit connection material 50 mentioned above are prepared (refer FIG. 4 (a)). Next, the film-form circuit connection material 50 is mounted on the surface (main surface 21a) in which the electrode 22 of the circuit member 20 is formed. In addition, when the film-form circuit connection material 50 is formed on a support body (not shown), for example, the circuit member (with the film-form circuit connection material 50 side facing the circuit member 20) ( 20) Put on. At this time, since the circuit connection material 50 is a film form, handling is easy. Therefore, the circuit connection material 50 can be easily interposed between the circuit member 20 and the circuit member 30, and the connection work of the circuit member 20 and the circuit member 30 can be performed easily.

In addition, the circuit connection material 50 is urged in the arrow A direction of FIG. 4 (a) and the circuit member 20 is pressed in the arrow B direction, respectively, and the circuit connection material 50 is applied to the circuit member 20. It connects (refer FIG. 4 (b)). Such temporary connection can also be performed by pressing, heating. However, heating temperature shall be lower than the temperature which the adhesive composition in the circuit connection material 50 does not harden, for example, the temperature at which a radical polymerization initiator generate | occur | produces a radical.

Subsequently, as shown in FIG. 4C, the circuit member 30 is placed on the circuit connection material 50 with the electrode 32 facing the circuit member 20. For example, when the circuit connection material 50 has a support body (not shown) on the opposite side to the circuit member 20, the circuit member 30 is placed on the circuit connection material 50 after peeling off the support body. Put it up.

In addition, while heating the circuit connection material 50 by a heating head etc., the circuit members 20 and 30 are pressurized in the direction of the arrow A and the arrow B of FIG. The connection is made. The heating temperature at the time of this connection is a temperature at which the low melting metal which is a main component of the conductive layer 14 of the electrically conductive particle 10 can melt, and makes a radical polymerization initiator the temperature which can generate | occur | produce a radical. As conditions at the time of this connection, heating temperature 130-250 degreeC and connection time can be made for 1 to 60 second. Accordingly, the softening point T ₄ first When the temperature of the vicinity is reached, the adhesive composition 52 flows. After that, softening point T ₃ In the vicinity, the insulating layer 16 of the conductive particles 10 is softened to exhibit fluidity. By pressing the circuit members 20 and 30 in the A direction and the B direction, respectively, the flow starts in the order of the adhesive composition 52 and the insulating layer 16, and the low melting point metal is mainly used on the surface of the conductive particles. The conductive layer 14 is exposed. That is, the insulating layer 16 is softened and simultaneously pressed by the first and second electrodes 22 and 32 so that the insulating layer 16 flows and selectively conducts the pressed portion of the conductive particles 10. Surface 14a (FIG. 2) of layer 14 is exposed.

If temperature rises further, melting point T ₂ of low melting point metal In the vicinity, the conductive layer 14 is melted. By this melting, joining of the 1st electrode 22 and the 2nd electrode 32 is performed through the low melting metal. In addition, such joining is performed by joining the low melting metals of the some electroconductive particle between the 1st electrode 22 and the 2nd electrode 32 as needed. At the same time, the conductive layer 14 also flows by being pressed by the electrode 22 and the electrode 32, and selectively the surface 12a of the core 12 is pressed to the pressed portion of the conductive particle 10 (FIG. 2). ) Is exposed. Thereby, the electrodes 22 and 32 and the core 12 of electroconductive particle directly contact. That is, the first electrode 22 and the second electrode 32 are connected through the low melting point metal part 114 and the core 12.

In addition, in the adhesive composition 52, a radical polymerization initiator generates a radical and polymerization of a radically polymerizable compound is started. In this way, the adhesive composition of the circuit connection material 50 is hardened and this connection is performed. As a result, the connection structure 24 of the circuit member as shown in FIG. 3 is obtained. In addition, the conditions of this connection can be suitably selected according to the composition of an adhesive composition, the material of a circuit member, the use of a bonded structure, etc. If necessary, post-curing may be performed after the connection.

Since the electroconductive particle 10 is equipped with the core 12, it is difficult to crush completely between the 1st electrode 22 and the 2nd electrode 32. As shown in FIG. Therefore, since the molten low melting point metals can be prevented from widening in the direction orthogonal to the pressing direction, the bonding between the plurality of conductive particles 10 in the direction can be prevented. In addition, since portions other than the above-mentioned exposed part in the surface 14a (FIG. 2) of the conductive layer 14 are coat | covered with the insulating layer 16, several electroconductive particle in the direction orthogonal to a pressurization direction Electrical conduction between the 10 can be prevented.

As described above, when the connection structure 24 of the circuit member is manufactured, the connection resistance between the opposing first electrode 22 and the second electrode 32 can be sufficiently reduced, and at the same time, adjacent to the same substrate. The insulation between the electrodes 22 and the electrodes 32 can be sufficiently improved.

In the bonded structure obtained by this connection mentioned above, in the state in which the distance between the electrode 22 and the electrode 32 became small enough, it has the insulating part 11 which hardened the adhesive composition (FIG. 3). In addition, since the conductive layer 14 is melted and solidified after being bonded to the electrodes 22 and 32, the circuit member 20 and the circuit member 30 are firmly connected through the circuit connecting portion 26. . In the connection structure 24 of the circuit member obtained, since the circuit connection part 26 is comprised by the hardened | cured material of the said circuit connection material, the circuit with respect to the 1st circuit member 20 and the 2nd circuit member 30 is carried out. The adhesive strength of the connecting portion 26 is sufficiently high.

Moreover, since the conductive layer 14 has a low melting metal as a main component, the process temperature at the time of manufacturing the connection structure 24 of a circuit member can be made low. Therefore, since the component which comprises the circuit member connection structure 24 does not require heat resistance by that much, it becomes possible to fully expand the range of material selection of the said component.

(Modification example of connection structure)

It is sectional drawing which shows typically a semiconductor device which is an example of the bonded structure of this 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 board | substrate 60, the semiconductor element connection member 40 (circuit connection part) which connects these electrically and mechanically is provided. The semiconductor element connection member 40 is provided on the main surface 60a 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 opposite to the semiconductor element 80. The semiconductor element connection member 40 is provided between the semiconductor element 80 and the board | substrate 60, and these are electrically and mechanically connected.

Although it does not restrict | limit especially as a constituent material of the semiconductor element 80, Group IV semiconductor materials, such as silicon and germanium, GaAs, InP, GaP, InGaAs, InGaAsP, AlGaAs, InAs, GaInP, AlInP, AlGaInP, GaNAs, GaNP, GaInNAs, Group III-V compound semiconductor materials such as GaInNP, GaSb, InSb, GaN, AlN, InGaN, InNAsP, II-VI compound semiconductor materials such as HgTe, HgCdTe, CdMnTe, CdS, CdSe, MgSe, MgS, ZnSe, ZeTe, Various materials, such as CuInSe (CIS), are mentioned.

The semiconductor element connection member 40 is comprised from the hardened | cured material of the circuit connection material of the said embodiment. The semiconductor element connection member 40 is the same as the circuit connection part 26, for example, the low-melting-point metal part 114 which consists of the material which has a core 12 and the low melting-point metal which comprises the conductive layer 14 as a main component. ), An insulating resin portion 116 made of a cured product of the resin composition constituting the insulating layer 16, and an insulating part 11 which is a cured product of the adhesive composition.

In the semiconductor device 100, the semiconductor element 80 and the circuit pattern 61 are electrically connected through the low melting point metal part 114. For this reason, the connection resistance between the semiconductor element 80 and the circuit pattern 61 is fully reduced. Therefore, the current flows between the semiconductor element 80 and the circuit pattern 61 can be made smooth, and the function which the semiconductor element 80 has can fully be exhibited. In addition, since the semiconductor element connection member 40 has excellent anisotropic conductivity, insulation between 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 connecting member 40, since the low melting point metal part 114, the semiconductor element 80, and the circuit pattern 61 are metal-bonded, the semiconductor element connection with respect to the semiconductor element 80 and the board | substrate 60 is carried out. The adhesive strength of the member 40 becomes high enough, and this state can be sustained for a long time. Thus, it becomes possible to sufficiently increase the long-term reliability of the electrical characteristics between the semiconductor element 80 and the substrate 60.

As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to the said embodiment at all.

For example, the film-form circuit connection material 50 can also be made into the multilayered structure (not shown) which consists of 2 or more types of layers in which Tg (glass transition temperature) of an adhesive composition differs 5 degreeC or more when it hardens.

<Examples>

Hereinafter, although this invention is demonstrated further more concretely based on an Example and a comparative example, this invention is not limited to a following example at all. Each of the softening point shown below _{(T 1s, T 3, T} 4) are Seiko Instruments Inc. using a thermal mechanical analyzer TMA / SS6000 of whether or sikki manufactured production as measured by a compression mode or a tensile mode, speed 5 ℃ / min temperature increase in Glass transition temperature.

(Example 1)

(1) Preparation of Conductive Particles

<Pretreatment>

Conibex C type (spherical phenolic resin, average particle diameter: 5 μm, Unitica Co., Ltd., softening point T _1s : 180 ° C.) was forcibly stirred in methyl alcohol, and pretreated with degreasing and roughening. It was. Thereafter, methyl alcohol was separated by filtration to obtain a pretreated polymer nuclear material (core).

<Activate>

The obtained polymer nuclear material was dispersed in Circuit Prep 3316 (PdCl ₂ + HCl + SnCl ₂ -based activation treatment liquid, Nippon Electroplating Engineers, Ltd., trade name), and stirred at 25 ° C. for 20 minutes to perform an activation treatment. Subsequently, washing with water and filtration gave a polymer nucleus whose surface was activated.

Electroless Ni Plating

The obtained polymer nucleus was immersed in a Blueschuma (electroless Ni plating solution, bath capacity of 300 µdm ² / l, Nippon Kaneni Co., Ltd. product) solution, and forcedly stirred at 90 ° C. for 30 minutes. Thereafter, water was washed and Ni-coated particles in which the polymer nucleus was coated with nickel plating were obtained.

Electroless Au Plating

Substitution plating of Au was performed to the surface of Ni coating particle | grains. As a plating liquid, the plating process was performed at 90 degreeC for 30 minutes using the electroless prep (electroless Au plating liquid, the Nippon Electroplating Engineers make, brand name). Thereafter, the mixture was washed well 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 thickness of Ni plating and Au plating was computed from the scanning electron microscope image of a particle cross section. In addition, the metal foil layer has a melting point of 1000 ° C or higher.

<Soldering Plating>

On the surface of the thus obtained Ni-Au coated particle, by using the barrel plating device subjected to eutectic solder plating (43% Sn-57% Bi , melting temperature (T ₂₎ 139 ℃) to obtain covered particles SnBi. As a result of observing the cut surface of the obtained SnBi coated particle with a scanning electron microscope (SEM), the thickness of the solder plating layer was 3 micrometers.

<Formation of Insulation Layer>

The insulating layer was formed in the surface of the obtained SnBi coating particle as follows, and electroconductive particle was manufactured. As a material of the insulating layer, a dimethylformamide (DMF) solution containing 1% by mass of paraprene P-25M (thermoplastic polyurethane resin, softening point T ₃ : 130 ° C, manufactured by Nippon Elastran Co., Ltd.) was manufactured. It was. SnBi coating particle | grains were added to this solution, and it stirred. Then, spray drying was performed at 100 degreeC for 10 minutes using the spray dryer (The Yamato Chemical Co., Ltd. make, brand name: GA-32 type), and obtained electroconductive particle. As a result of cross-sectional observation by a scanning electron microscope (SEM), the average thickness of the insulating layer of this electrically conductive particle was about 1 micrometer.

(2) Manufacture of circuit connection material

The film-form circuit connection material was manufactured with the following procedures. First, 50 g of phenoxy resin (Union Carbide Co., Ltd. make, brand name: PKHC, average molecular weight: 45,000) is made into toluene (boiling point 110.6 degreeC, SP value 8.90) / ethyl acetate (boiling point 77.1 degreeC, SP value 9.10) by mass ratio. It dissolved in the mixed solvent of = 50/50, and prepared the phenoxy resin dispersion liquid of 40 mass% of solid content.

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

As a radical polymerization initiator, di-2-ethylhexyl peroxy dicarbonate (Nippon Yushi Co., Ltd. make, brand name: Perroyl OPP) was prepared.

Each material prepared as mentioned above was converted into solid content, it mix | blended in the following mass ratio, and the adhesive liquid which added and disperse | distributed the electrically-conductive particle manufactured as mentioned above was obtained. In addition, the addition amount of electroconductive particle was made to be 3 mass% with respect to the whole circuit connection material obtained.

ㆍ PKHC: 50

80MFA: 50

ㆍ P-2M: 10

ㆍ Frorole OPP: 5

Next, the obtained adhesive liquid was apply | coated to the 80-micrometer-thick fluororesin film using a coating apparatus, and the film-form circuit connection material of 20 micrometers in thickness was obtained by hot air drying for 10 minutes at 70 degreeC. The obtained film-form circuit connection material showed sufficient flexibility at room temperature.

(3) Preparation of bonded structure

Next, a flexible substrate having an Au plating circuit having a line width of 25 μm, a pitch of 50 μm, and a thickness of 8 μm (manufactured by Hitachi Super LSI System, trade name: COF TEG_50A), and an Au bump having a pitch of 50 μm (bump size 30). A semiconductor device (manufactured by Hitachi-cho LSI system, trade name: JTEG Phase 6_50) having a size of 100 m was prepared. The film-form circuit connection material (untreated, width 2mm) manufactured as mentioned above is arrange | positioned between a flexible board | substrate and a semiconductor element, and it uses the thermocompression bonding apparatus (heating system: continuous heating type, Toray Engineering Co., Ltd. make). 15 degreeC heating and pressurization were performed at 160 degreeC and 3 MPa. In addition, pressurization was performed in the direction which a flexible substrate and a semiconductor element oppose. In this way, the connection structure of a circuit member (connection structure of a semiconductor element / flexible board | substrate) was produced.

(Example 2)

FR-4 substrate having an Au bump (bump size: 70 μm × 70 μm) with a pitch of 130 μm (Hitachi Ultra LSI System, trade name: JTEG Phase0-GB), and an Au plated pad with a pitch of 130 μm. Hitachi Ultra LSI System, JKIT Type II) was prepared. Furthermore, the film-form circuit connection material (untreated, 2.5 mm x 2.5 mm) manufactured similarly to Example 1 between a FR-4 board | substrate and a semiconductor element is arrange | positioned, and the thermocompression bonding apparatus (heating system: continuous heating type, Toray Engineering Co., Ltd.) was heated and pressurized for 15 second at 160 degreeC and 3 MPa. In this way, the connection structure of a circuit member (connection structure of a semiconductor element / FR-4 board | substrate) was manufactured.

(Comparative Example 1)

Except not having solder plating, it carried out similarly to Example 1, and manufactured electroconductive particle. As a result of cross-sectional observation by a scanning electron microscope (SEM), the average thickness of the insulating layer of this electrically conductive particle was about 1 micrometer similar to Example 1. Moreover, it carried out similarly to Example 1 using the said electroconductive particle, and produced the circuit connection material, and obtained the connection structure (connection structure of a semiconductor element / flexible board | substrate).

(Comparative Example 2)

Except having used the electrically-conductive particle produced by the comparative example 1 as a electrically-conductive particle, it carried out similarly to Example 2, and manufactured the circuit connection material, and obtained the connection structure (connection structure of a semiconductor element / FR-4 board | substrate).

(Comparative Example 3)

Except not having formed an insulating layer, it carried out similarly to Example 1, and manufactured electroconductive particle. In the same manner as in Example 1, a circuit connection material was manufactured, and a connection structure (connection structure of a semiconductor element / flexible board) was obtained.

 <Measurement of connection resistance>

The connection resistance between the opposing circuit members of the bonded structure manufactured by each said Example and each comparative example was measured. Specifically, the connection resistance of the circuit which daisy-chained all the electrodes of each connection structure was measured using the ADVANTEST digital multimeter R6871E. At this time, the measurement current was 1 mA. The measurement result was as showing in Table 1. In the case of using the circuit connection material having the low melting point metal layer inside the conductive particles (Examples 1 and 2), the circuit connection material ensured conduction only by contact with the high melting point metals (Au and Ni), which do not have the low melting point metal layer. The connection resistance was lower than that of (Comparative Examples 1 and 2).

<Temperature cycle life>

Temperature resistance cycle life of the bonded structure manufactured by each said Example and each comparative example was evaluated. The temperature range in the measurement was made into a minimum of -40 degreeC and an upper limit of 125 degreeC, and made the holding time in a minimum and an upper limit temperature 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 normal temperature were made into one cycle, and these cycles were repeated to evaluate the temperature cycle resistance. Evaluation was performed by taking out a bonded structure from the temperature cycle test apparatus every 100 cycles, measuring a connection resistance, and measuring the number of cycles until an open defect generate | occur | produces.

The measurement result was as showing in Table 1. The connection structure (Examples 1 and 2) using the circuit connection material which has a low melting metal layer in electroconductive particle does not have a low melting metal layer, and has the circuit connection material which ensured conduction only by the contact of high melting metals (Au, Ni). It was confirmed that the temperature resistance cycle life is longer than that of (Comparative Examples 1 and 2). In addition, when the electrically-conductive particle which does not have an insulating layer was used (comparative example 3), when manufacturing a bonded structure, adjacent electrically-conductive particles were fused and adjacent electrodes were conducting, and the short circuit (short) generate | occur | produced. For this reason, temperature cycling resistance could not be evaluated.

According to the present invention, it is possible to provide a circuit connection material that is sufficiently excellent in connection reliability capable of maintaining good insulation and good conductivity over a long period of time. Moreover, the electroconductive particle suitable for using for such a circuit connection material can be provided.

Claims (7)

As a circuit connection material for connecting the 1st electrode and the 2nd electrode which mutually oppose,
Having an adhesive composition and conductive particles dispersed in the adhesive composition,
The adhesive composition contains a thermosetting resin,
The conductive particles include a core comprising a material having a melting point or a softening point of T ₁ (° C.), a conductive layer comprising a low melting point metal having a melting point T ₂ (° C.) of 130 to 250 ° C. covering the surface of the core. And an insulating layer made of a resin composition having a softening point of T ₃ (° C.) covering the surface of the conductive layer, wherein T ₁ , T _2, and T ₃ satisfy the following Equation 1,
The said adhesive composition has fluidity | liquidity by heating, and the circuit connection material which hardens after joining the said conductive layer containing the said 1st electrode, the said 2nd electrode, and the said low melting metal.
&Quot; (1) &quot;
T ₁ > T ₂ > T ₃ The circuit connection material of Claim 1 whose content of the said electroconductive particle is 1-10 mass%. The circuit connection material of Claim 1 whose shape is a film form. As a circuit connection material for connecting the 1st electrode and the 2nd electrode which mutually oppose,
Having an adhesive composition and conductive particles dispersed in the adhesive composition,
The adhesive composition contains a thermosetting resin,
The conductive particles include a core comprising a material having a melting point or a softening point of T ₁ (° C.), a conductive layer comprising a low melting point metal having a melting point T ₂ (° C.) of 130 to 250 ° C. covering the surface of the core. And an insulating layer made of a resin composition having a softening point of T ₃ (° C.) covering the surface of the conductive layer,
When the softening point of the adhesive composition is T ₄ , the T ₁ , T ₂ , T ₃ and T ₄ satisfy the following formula (2).
&Quot; (2) &quot;
T ₁ > T ₂ > T ₃ > T ₄ The circuit connection material of Claim 4 whose content of the said electroconductive particle is 1-10 mass%. The circuit connection material of Claim 4 whose shape is a film form. A first circuit member having a first circuit electrode formed on the first substrate,
A second circuit member formed on a second substrate, the second circuit member disposed so that the second circuit electrode and the first circuit electrode face each other;
As a connection structure provided between the said 1st board | substrate and the said 2nd board | substrate, and a circuit connection part which connects the said 1st circuit member and the said 2nd circuit member,
The said circuit connection part contains the hardened | cured material of the circuit connection material of any one of Claims 1-6, The said 1st circuit electrode and the said 2nd circuit electrode are contained in the said conductive layer of the said electrically-conductive particle. A connecting structure electrically connected through a low melting point metal.

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