JPH1150032A - Connection member for circuit and circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject connection member for the connection of circuit boards with each other or a circuit board with an electronic part such as IC chip by using an adhesive composition containing an epoxy resin and a latent curing agent as essential components. SOLUTION: The objective circuit connection member is produced by using an adhesive composition containing (A) an epoxy resin containing dispersed rubber particles of 0.02-1 μm diameter and (B) a latent curing agent of the epoxy resin as essential components, preferably (C) a mixture of a rubber emulsion and an epoxy resin. Oppositely placed electrodes can be electrically connected with the connection member by heating and pressing the electrodes in the connecting direction. The objective connection member may be incorporated preferably in the adhesive composition with a phenoxy resin having a weight-average molecular weight of 20,000-60,000 and 0.1-20 pts.vol. (based on 100 pts.vol. of the composition) of electrically conductive particles having an average particle diameter of 1-18 μm in a form dispersed in the composition. The connection member may have a film form.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit connecting member and a circuit board used for connecting circuit boards to each other or an electronic component such as an IC chip and the circuit board.

[0002]

2. Description of the Related Art An adhesive or an anisotropic conductive adhesive in which conductive particles are dispersed is used to electrically connect circuit boards to each other or to connect an IC chip or electronic component to a circuit board. That is, these adhesives are arranged between the electrodes, and after the electrodes are connected to each other by heating and pressing, electrical connection can be performed by giving conductivity in the pressing direction. For example, JP-A-3-16147 proposes an adhesive for circuit connection based on an epoxy resin.

[0003]

However, an adhesive using a conventional adhesive using an epoxy resin as a base resin has a difference in the coefficient of thermal expansion of the connection substrate when a reliability test such as a thermal shock test or a PCT test is performed. There is a problem that the connection stress increases in the connection portion and the adhesive is peeled off due to the internal stress based on the above. In particular, when the chip is directly mounted on a substrate via an adhesive, a printed circuit board using an FR-4 base material as a connection substrate, or a flexible wiring board based on polyimide or polyester is used as a connection substrate. Warpage of the chip and the substrate is likely to occur due to the internal stress based on the difference in thermal expansion coefficient of the chip. The present invention provides a circuit connecting member which is used for connecting circuit boards to each other or an electronic component such as an IC chip and enables excellent connection reliability, and a circuit board having excellent connection reliability.

[0004]

A circuit connecting member according to the present invention is a circuit connecting member for electrically connecting opposing circuit electrodes by heating and pressurizing, thereby electrically connecting the electrodes in the pressing direction. The circuit connecting member comprises: (A) an epoxy resin in which rubber particles having a diameter of 0.02 to 1 micron are dispersed; and (B) an adhesive composition containing a latent curing agent of an epoxy resin as an essential component. Features.

[0005] A circuit connecting member of the present invention is a circuit connecting member for electrically connecting opposing circuit electrodes by heating and pressurizing the electrodes in the pressing direction. (C) a mixture of a rubber emulsion and an epoxy resin; and (B) an adhesive composition containing a latent curing agent for the epoxy resin as an essential component. In the mixture (C) of the rubber emulsion and the epoxy resin, the diameter of the rubber particles dispersed in the rubber emulsion is from 0.02 to 1
Preferably it is microns. In the circuit connecting member, the adhesive composition may contain a phenoxy resin, and the phenoxy resin has a weight average molecular weight of 20,000 to 2,000.
60000 is preferred. In the circuit connecting member, conductive particles having an average particle diameter of 1 to 18 microns can be dispersed in the adhesive composition, and the content of the conductive particles is based on 100 parts by volume of the adhesive composition. , 0.1 to 20 parts by volume is preferred. The shape of the circuit connecting member may be a film shape, and the area of the circuit connecting member after connection may be 2.0 to 5.0 times the area before connection. .

[0006] The circuit board of the present invention comprises a first circuit member having a first connection terminal and a second circuit member having a second connection terminal, the first connection terminal and the second connection terminal. Are arranged facing each other, a circuit connecting member is interposed between the first connecting terminal and the second connecting terminal arranged opposite to each other, and the first connecting terminal and the second arranged facing each other are heated and pressurized. A circuit board in which connection terminals are electrically connected, wherein the circuit connection member comprises: (A) an epoxy resin in which rubber particles having a diameter of 0.02 to 1 micron are dispersed; and (B) an epoxy resin potential. It is an adhesive containing an adhesive composition containing a curing agent as an essential component.

Further, the circuit board of the present invention comprises a first circuit member having a first connection terminal and a second circuit member having a second connection terminal, the first connection member being connected to the second connection member. Terminals are arranged to face each other, a circuit connecting member is interposed between the first and second connection terminals, and the first and second connection terminals are heated and pressurized to form a second connection terminal. A circuit board in which the connection terminals are electrically connected, wherein the circuit connection member comprises: (C) a mixture of a rubber emulsion and an epoxy resin; and (B) an adhesive containing a latent curing agent of an epoxy resin as an essential component. It is characterized in that it is an adhesive containing the composition.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The epoxy resin used in the present invention is:
Bisphenol type epoxy resin derived from epichlorohydrin and bisphenol A or F, AD, etc., epoxy novolak resin derived from epichlorohydrin and phenol novolak or cresol novolak or naphthalene-based epoxy resin having a skeleton containing a naphthalene ring,
Glycidylamine, glycidyl ester, biphenyl,
Various epoxy compounds having two or more glycidyl groups in one molecule, such as alicyclic compounds, can be used alone or in combination of two or more. For these epoxy resins, it is preferable to use high-purity products in which impurity ions (Na +, C1-, etc.), hydrolyzable chlorine and the like are reduced to 300 ppm or less, in order to prevent electron migration.

The rubber particles of the present invention have a diameter of 0.02 to 1 micron and are dispersed in an epoxy resin. The rubber particles can be uniformly dispersed in the epoxy resin as primary particles. Rubber particles having a diameter of 0.02 to 1 micron
It is preferably at least 70% by volume of all rubber particles, more preferably at least 90% by volume. The epoxy resin (A) in which rubber particles having a diameter of 0.02 to 1 micron are dispersed can be obtained by directly mixing a rubber emulsion with the epoxy resin and performing a dehydration treatment.

In the present invention, a mixture (C) of a rubber emulsion and an epoxy resin can be used. In this case, the diameter of the rubber particles dispersed in the rubber emulsion is
Preferably it is between 0.02 and 1 micron. 0.0
The rubber particles having a diameter of 2 to 1 micron are preferably at least 70% by volume, more preferably at least 90% by volume of the total rubber particles.

[0011] The rubber emulsion of the present invention can be obtained by emulsion polymerization,
It is an aqueous dispersion of rubber obtained from suspension polymerization or solution polymerization, for example, acrylic emulsion, SBR,
NBR and the like are used singly or as a mixture of two or more kinds. In particular, an acrylic rubber emulsion having a glass transition temperature of room temperature or lower, which is obtained by emulsion polymerization of a (meth) acrylate-based monomer, is suitable. is there. The particle size of the rubber particles is preferably about 0.02 to 1 micron, but more preferably 0.1 to 0.6 micron from the viewpoint of the cured physical properties and workability of the epoxy resin composition. The rubber particles having such a particle size are preferably 70% by volume or more of all the rubber particles, and more preferably 90% by volume or more.

The epoxy resin composition obtained by mixing and dewatering a rubber emulsion and an epoxy resin in the present invention is obtained by directly mixing a rubber emulsion with an epoxy resin and removing water while stirring under normal pressure or reduced pressure. Is obtained. At this time, if the treatment is further performed with a high-pressure homogenizer after removing the water, the viscosity of the epoxy resin composition decreases, and the workability at the time of preparing the adhesive composition is improved. The amount of rubber particles dispersed in the epoxy resin composition is preferably from 1 to 60 parts by weight, more preferably from 2 to 30 parts by weight, per 100 parts by weight of the epoxy resin.

Examples of the latent curing agents for epoxy resins include imidazoles, hydrazides, boron trifluoride-amine complexes, sulfonium salts, amine imides, diamino maleonitriles, melamines and derivatives thereof, polyamine salts, dicyandiamide and the like. There are denatured products,
These can be used alone or as a mixture of two or more. These are anionic or cationically polymerizable catalytic curing agents, and are preferred because they can easily obtain fast curing properties and require little consideration of chemical equivalents. As a curing agent,
In addition, polyaddition of polyamines, polymercaptans, polyphenols, acid anhydrides and the like can be applied, or the catalyst can be used in combination with the catalyst type curing agent.

The anionic polymerization type catalyst type curing agent includes:
Epoxy resins containing tertiary amines or imidazoles have a relatively long pot life because they are cured by heating at a medium temperature of about 160 to 200 ° C. for several tens of seconds to several hours. As the cationic polymerization type catalyst-type curing agent, a photosensitive onium salt that cures a resin by irradiation with energy rays, for example, an aromatic diazonium salt, an aromatic sulfonium salt, or the like is mainly used. In addition, aliphatic sulfonium salts and the like can be activated by heating in addition to energy beam irradiation to cure the epoxy resin. This type of curing agent is preferred because it has the characteristic of fast curing.

When these curing agents are microencapsulated by coating them with a polymeric substance such as polyurethane or polyester, a metal thin film such as Ni or Cu, or an inorganic substance such as calcium silicate, the pot life is extended. It is preferable because it is possible.

[0016] In the adhesive composition obtained above, for example, fillers, softeners, accelerators, antioxidants, coloring agents, flame retardants, thixotropic agents, coupling agents, and the like as ordinary additives. A curing agent such as a phenol resin, a melamine resin, and an isocyanate may be contained.

The phenoxy resin used in the present invention will be described. The phenoxy resin has a weight average molecular weight of 1000 determined by high performance liquid chromatography (HLC).
It corresponds to a high molecular weight epoxy resin of 0 or more, and similarly to the epoxy resin, there are other types such as bisphenol A type, AD type and AF type. Since these have similar structures to epoxy resins, they have good compatibility and good adhesiveness. The larger the molecular weight, the more easily the film-forming properties can be obtained, and the melt viscosity which affects the fluidity at the time of connection can be set in a wide range. The weight average molecular weight is 10,000 to 80
000 is more preferable in view of the melt viscosity and compatibility with other resins, and 20,000 to 60,000 phenoxy resin is more preferable. When these resins contain a polar group such as a hydroxyl group or a carboxyl group, the compatibility with the epoxy resin is improved, and a film having a uniform appearance and properties can be obtained. It is preferable from the viewpoint of obtaining curing. The compounding amount is 20 parts with respect to the entire resin component from the viewpoint of promoting film forming property and curing reaction.
It is preferably set to 80% by weight. In addition, a styrene-based resin, an acrylic resin, or the like may be appropriately mixed for melt viscosity adjustment or the like.

As the conductive particles, Au, Ag, Ni,
There are metal particles such as Cu and solder, carbon, and the like, and the conductive layer described above may be formed by coating the above conductive layer with non-conductive glass, ceramic, plastic, or the like.
In the case of plastic core or hot melt metal particles,
Heat and pressure are preferable because they have deformability, so that the contact area with the electrode increases during connection and reliability is improved. The conductive particles are properly used in a wide range of 0.1 to 30% by volume with respect to 100 parts by volume of the adhesive component. In order to prevent a short circuit of an adjacent circuit due to excessive conductive particles, 0.1 to
More preferably, the content is 10% by volume.

The adhesive composition of the present invention is particularly useful as a one-part adhesive, especially as a film adhesive for bonding a liquid crystal panel or a semiconductor chip. In this case, for example, the adhesive composition obtained above is liquefied as a solvent or a dispersion in the case of an emulsion, and is formed on a release substrate such as release paper, or is mixed with a substrate such as a nonwoven fabric. The solution may be impregnated to form on the peelable substrate, dried at a temperature lower than the activation temperature of the curing agent, and the solvent or the dispersion may be removed. At this time, a mixed solvent of an aromatic hydrocarbon type and an oxygen-containing type is preferably used as the solvent for improving the solubility of the material. Here, the SP value of the oxygen-containing solvent is preferably in the range of 8.1 to 10.7 from the viewpoint of protection of the latent curing agent, and acetates are more preferable. Further, the boiling point of the solvent can be 150 ° C. or less. When the boiling point exceeds 150 ° C, high temperature is required for drying,
Since the temperature is close to the activation temperature of the latent curing agent, the potential is reduced, and at low temperatures, the workability during drying is reduced. For this reason, the boiling point is preferably from 60 to 150C, more preferably from 70 to 130C.

The ratio of the area after connection of the adhesive to the area before connection is measured by the following means. That is, the thickness 50
A 5 μm square adhesive having a thickness of 5 μm is sandwiched between two glass plates having a thickness of 1.1 mm and a size of 15 mm square. This was heated at 180 ° C. and pressurized at 18 kgf /
Heating and pressurizing are performed under the conditions of cm ² and pressurizing time of 20 seconds, and the area of the adhesive before heating and pressing (A) and the area of the adhesive before heating and pressing (B) are measured using an image processing apparatus. By measuring, the ratio of the area after connection of the adhesive to the area before connection (B /
A) can be obtained. If the ratio (B / A) of the area after the connection of the adhesive to the area before the connection is less than 2.0, the releasability of the molten adhesive between the connection electrodes or at the interface between the connection electrode and the conductive particles is reduced. It becomes difficult to secure electrical conduction between the connection electrodes or between the connection electrodes and the conductive particles. On the other hand, the ratio (B / A) of the area after connection of the adhesive to the area before connection is 5.
If it exceeds 0, the fluidity of the adhesive at the time of connection is too high,
Air bubbles tend to be generated, and as a result, reliability tends to decrease.

In the case of a film-like adhesive, the adhesive layer can be multi-layered. For example, a two-layer anisotropic conductive film or an adhesive film filled with conductive particles in which an adhesive film filled with conductive particles and an adhesive layer not filled with conductive particles to impart anisotropic conductivity are laminated. Can be used a three-layered anisotropic conductive film in which an adhesive layer not filled with conductive particles on both sides is turned into a raminate.
These multi-layered anisotropic conductive films are advantageous for narrow pitch connection because they can efficiently capture conductive particles on connection electrodes. Also, in consideration of the adhesiveness with the circuit member, the circuit members 1 and 2 may be laminated with an adhesive film having excellent adhesiveness to form a multilayer.

Circuit components used in the circuit board of the present invention include electronic components such as active elements such as semiconductor chips, transistors, diodes and thyristors, passive elements such as capacitors, resistors and coils, printed circuit boards, and polyimides. And a glass substrate on which a circuit such as a flexible wiring board made of polyester or ITO is formed. On the electrode pads of the semiconductor chip and substrate, the tip of the bump or gold wire formed by plating is melted with a torch or the like, a gold ball is formed, and this ball is pressed on the electrode pad,
A protruding electrode such as a wire bump obtained by cutting a wire is provided and can be used as a connection terminal. The above-mentioned circuit members are usually provided with a large number of connection terminals (in some cases, a single terminal may be provided), and at least one set of the circuit members is disposed so that at least a part of the connection terminals provided on the circuit members is opposed to each other. Then, an adhesive is interposed between the opposed connection terminals and heated and pressed to electrically connect the opposed connection terminals to form a circuit board. By heating and pressing at least one set of the circuit members, the connection terminals arranged opposite to each other are electrically connected by direct contact or via conductive particles.

[0023]

【Example】

Example 1 Bisphenol A type phenoxy resin (average molecular weight 30,000) 6 from bisphenol A and epichlorohydrin
0 g was prepared by a general method, and this was mixed in a weight ratio of toluene (boiling point 110.6 ° C., SP value 8.90) / ethyl acetate (boiling point 77.1 ° C., SP value 9.10) = 50/50. It was dissolved in a solvent to obtain a bisphenol-A phenoxy resin solution having a solid content of 30% by weight. Ethyl acrylate 80
20 parts by weight of an acrylic rubber emulsion obtained by emulsion polymerization of 10 parts by weight of methyl methacrylate, 10 parts by weight of methyl methacrylate, and 10 parts by weight of glycidyl methacrylate with an emulsifier which is a polymer having a terminal alkyl group, and 80 parts by weight of a bisphenol A type epoxy resin. After stirring and heating to remove water, the mixture was treated with a high-pressure homogenizer to obtain a liquid epoxy resin in which acrylic rubber particles having a diameter of 0.3 μm were primarily dispersed. 30 parts by weight of the acrylic rubber particle-dispersed liquid epoxy resin was mixed with the bisphenol-A phenoxy resin solution (resin weight: 30 parts) having a solid content of 30% by weight.
Then, Novacure 3 as a latent curing agent was added to the mixed solution.
941 HPS (a masterbatch-type curing agent obtained by dispersing a microcapsule-type curing agent having an average particle diameter of 5 μm having a modified imidazole core as a core and covering the surface with polyurethane in a liquid bisphenol F-type epoxy resin, activation temperature At 125 ° C., 40 parts of Asahi Kasei Kogyo Co., Ltd. were added, and a nickel layer having a thickness of 0.2 μm was further provided on the surface of the conductive particles (particles having polystyrene as a core). A gold layer of 0.02 μm was provided to produce conductive particles having an average particle size of 5 μm and a specific gravity of 2.5)
Was dispersed in 5 parts by volume (based on 100 parts by volume of the adhesive composition), applied to a fluororesin film having a thickness of 80 μm using a coating device, and dried at 75 ° C. for 10 minutes with hot air to obtain a thickness of the adhesive layer. Of 50 μm was obtained. (Circuit Connection) Using the above-described circuit connecting member, a chip (10 mm × 10 mm) with a gold bump (area: 80 μm × 80 μm, height: 15 μm) and a Ni / Au plated copper circuit having a line width of 50 μm, a pitch of 100 μm, and a thickness of 18 μm were formed. The connection of the flexible circuit board (FPC) was performed as shown below. Circuit connection member (12 mm x 12
mm) on a Ni / Au plated Cu circuit printed circuit board.
After sticking at 10 ° C and 10 kgf / cm ² , the fluororesin film was peeled off, and the bumps on the chip and Ni / Au plating C
The alignment of the u circuit FPC was performed. Then 170
Heating and pressurizing were performed from above the chip under the conditions of 30 ° C., 30 g / bump, and 20 seconds, and the main connection was performed. The connection resistance after this connection is 6 mΩ at the maximum per bump, 2 mΩ on average, and the insulation resistance is 10 ⁸ Ω or more. These values are −55 to 12
Even after 1000 cycles of thermal shock test at 5 ° C., 200 hours of PCT test (121 ° C., 2 atm) and 10 seconds after immersion in a solder bath at 260 ° C., good connection reliability was exhibited.

Example 2 Bisphenol A-type phenoxy resin (average molecular weight 30,000) was prepared from bisphenol A and epichlorohydrin.
0 g was prepared by a general method, and this was mixed in a weight ratio of toluene (boiling point 110.6 ° C., SP value 8.90) / ethyl acetate (boiling point 77.1 ° C., SP value 9.10) = 50/50. It was dissolved in a solvent to obtain a bisphenol-A phenoxy resin solution having a solid content of 30% by weight. Ethyl acrylate 80
20 parts by weight of an acrylic rubber emulsion obtained by emulsion polymerization of 10 parts by weight of methyl methacrylate, 10 parts by weight of methyl methacrylate, and 10 parts by weight of glycidyl methacrylate with an emulsifier which is a polymer having a terminal alkyl group, and 80 parts by weight of a bisphenol A type epoxy resin. After stirring and heating to remove water, the mixture was treated with a high-pressure homogenizer to obtain a liquid epoxy resin in which acrylic rubber particles having a diameter of 0.3 μm were primarily dispersed. 30 parts by weight of the acrylic rubber particle-dispersed liquid epoxy resin was mixed with the bisphenol-A phenoxy resin solution (resin weight: 30 parts) having a solid content of 30% by weight.
Then, Novacure 3 as a latent curing agent was added to the mixed solution.
941 HPS (a masterbatch-type curing agent obtained by dispersing a microcapsule-type curing agent having an average particle diameter of 5 μm having a modified imidazole core as a core and covering the surface with polyurethane in a liquid bisphenol F-type epoxy resin, activation temperature At 125 ° C., 40 parts of Asahi Kasei Kogyo Co., Ltd. were added, and a nickel layer having a thickness of 0.2 μm was further provided on the surface of the conductive particles (particles having polystyrene as a core). A gold layer of 0.02 μm was provided to produce conductive particles having an average particle size of 5 μm and a specific gravity of 2.5)
Was dispersed in 5 parts by volume (based on 100 parts by volume of the adhesive composition), applied to a fluororesin film having a thickness of 80 μm using a coating device, and dried at 75 ° C. for 10 minutes with hot air to obtain a thickness of the adhesive layer. Was 25 μm. Then, a film coating solution prepared in the same manner except that the conductive particles were not dispersed in the preparation of the film coating solution was applied to a fluororesin film having a thickness of 80 μm by a coating apparatus, and the coating was performed at 75 ° C. for 10 minutes. After drying, an adhesive film b having a thickness of 25 μm was prepared. (Circuit Connection) Using the above-described circuit connecting member, a chip (10 mm × 10 mm) with a gold bump (area: 80 μm × 80 μm, height: 15 μm) and a Ni / Au plated copper circuit having a line width of 50 μm, a pitch of 100 μm, and a thickness of 18 μm were formed. The connection of the flexible circuit board (FPC) was performed as shown below. Circuit connection member (12 mm x 12
mm) on a Ni / Au plated Cu circuit printed circuit board at 80 ° C. and 10 kgf / cm ² , the fluororesin film is peeled off, and the chip bumps and the Ni / Au plated Cu circuit FPC are removed. Alignment was performed. Then, heating and pressurization were performed from above the chip under the conditions of 170 ° C., 30 g / bump, and 20 seconds, and the main connection was performed.
The connection resistance after this connection is up to 4 mΩ per bump,
The average is 2 mΩ and the insulation resistance is 10 ⁸ Ω or more. These values are 1000 cycles of thermal shock test at −55 to 125 ° C., PCT test (121 ° C., 2 atm) for 200 hours,
There was no change even after 10 seconds of immersion in the solder bath at 60 ° C., indicating good connection reliability.

[0025]

As described above, according to the circuit connecting member and the circuit board of the present invention, the stress at the circuit connecting interface can be reduced, the connection resistance at the connecting portion can be increased even after the reliability test, and the adhesive can be used. There is no peeling, and connection reliability is greatly improved.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuhiro Isaka 48 Wadai, Tsukuba, Ibaraki Prefecture, Hitachi Chemical Co., Ltd.Tsukuba R & D Co., Ltd. Within the Research Laboratory (72) Inventor Kazuyoshi Kojima 48 Wadai, Tsukuba, Ibaraki Prefecture Within Tsukuba Development Laboratory, Hitachi Chemical Co., Ltd.

Claims (12)

[Claims] 1. A circuit connecting member for electrically connecting opposing circuit electrodes by heating and pressurizing the electrodes in a pressurizing direction, wherein the circuit connecting member comprises (A) 0.02 Epoxy resin in which rubber particles having a diameter of 1 micron are dispersed. (B) A circuit connecting member comprising an adhesive composition containing a latent curing agent of an epoxy resin as an essential component. 2. A circuit connecting member for electrically connecting opposing circuit electrodes by heating and pressurizing the electrodes in a pressing direction, the circuit connecting member comprising (C) a rubber emulsion and an epoxy. Resin mixture (B) A circuit connecting member comprising an adhesive composition containing a latent curing agent of an epoxy resin as an essential component. 3. The circuit connecting member according to claim 2, wherein the diameter of the rubber particles dispersed in the rubber emulsion is 0.02 to 1 μm. 4. The circuit connecting member according to claim 1, wherein the adhesive composition contains a phenoxy resin. 5. A phenoxy resin having a weight average molecular weight of 20.
The circuit connecting member according to claim 4, wherein the number is from 000 to 60000. 6. The circuit connecting member according to claim 1, wherein conductive particles having an average particle diameter of 1 to 18 microns are dispersed in the adhesive composition. 7. The adhesive composition according to claim 1, wherein the content of the conductive particles is
7. The circuit connecting member according to claim 6, wherein the amount is 0.1 to 20 parts by volume with respect to 00 parts by volume. 8. The circuit connecting member according to claim 1, wherein the shape is a film. 9. The area after connection of the circuit connecting member is 2.0 to 5.0 times the area before connection.
Item 8. The circuit connecting member according to any one of Items 8 to 8. 10. A first circuit member having a first connection terminal and a second circuit member having a second connection terminal are arranged with the first connection terminal and the second connection terminal facing each other. Then, a circuit connecting member is interposed between the first connection terminal and the second connection terminal arranged opposite to each other, and the first connection terminal and the second connection terminal arranged opposite to each other by heating and pressing are electrically connected. Wherein the circuit connecting member comprises: (A) an epoxy resin in which rubber particles having a diameter of 0.02 to 1 micron are dispersed; (B) an epoxy resin latent curing agent as an essential component. A circuit board, which is an adhesive containing the adhesive composition described above. 11. A first circuit member having a first connection terminal and a second circuit member having a second connection terminal are arranged with the first connection terminal and the second connection terminal facing each other. Then, a circuit connecting member is interposed between the first connection terminal and the second connection terminal arranged opposite to each other, and the first connection terminal and the second connection terminal arranged opposite to each other by heating and pressing are electrically connected. Wherein the circuit connecting member comprises: (C) a mixture of a rubber emulsion and an epoxy resin; and (B) an adhesive containing an adhesive composition containing a latent curing agent of an epoxy resin as an essential component. A circuit board characterized by being an agent. 12. The circuit board according to claim 11, wherein the diameter of the rubber particles dispersed in the rubber emulsion is 0.02 to 1 micron.