JP2009194359A - Adhesive film for circuit connection, and connection structure of circuit member and method of connecting circuit member using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive film for circuit connection, which is adaptable to high resolution, is excellent in long-term connection reliability, and has excellent workability. <P>SOLUTION: The adhesive film for circuit connection connects a first circuit member in which first circuit electrodes are formed on a main surface of a first substrate and a second circuit member in which second circuit electrodes are formed on a main surface of a second substrate in a condition where the first circuit electrodes and the second circuit electrodes are arranged in a face-to-face configuration, wherein the adhesive film for circuit connection comprises at least an electrically conductive adhesive layer containing electrically-conductive grains and an adhesive, a first insulating adhesive layer formed on a surface of the electrically conductive adhesive layer, and a second insulating adhesive layer formed on a surface opposite to the one on which the first insulating adhesive layer is formed of the electrically conductive adhesive layer, wherein the thickness of the electrically conductive adhesive layer is two times or less of the average grain diameter of the electrically conductive grains, and the storage modulus of the electrically conductive adhesive layer at 40°C is 0.1 to 1.5 GPa. A connection structure of the circuit members and a method of connecting the circuit members using the adhesive film for circuit connection are also disclosed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an adhesive film for circuit connection, a circuit member connection structure using the same, and a circuit member connection method, and more particularly to connection between circuit boards or electronic components such as IC chips and a wiring board. The present invention relates to an adhesive film for circuit connection used, a circuit member connection structure using the same, and a circuit member connection method.

  When electrically connecting circuit boards or an electronic component such as an IC chip and a circuit board, an anisotropic conductive adhesive in which conductive particles are dispersed in an adhesive is used. That is, this anisotropic conductive adhesive is disposed between the electrodes of the circuit members facing each other, and the electrodes are connected by heating and pressurization, thereby providing conductivity in the pressurization direction and forming adjacent to each other. Insulating properties can be imparted to the electrodes that are provided so that only the electrodes facing each other can be electrically connected. As such an anisotropic conductive adhesive, for example, an adhesive for circuit connection based on an epoxy resin has been proposed (see, for example, Patent Document 1).

  The basic idea for increasing the resolution of the above-mentioned adhesive for circuit connection, that is, miniaturization of the electrode area and the space between adjacent electrodes, is to make the particle size of the conductive particles smaller than the insulating part between the adjacent electrodes. By ensuring the insulation between adjacent electrodes, the content of the conductive particles is set so that the particles do not come into contact with each other, and the conductive particles are surely present on the electrodes, so that the conductivity between the opposing electrodes is It is to get sex.

  However, in the above conventional method, when the particle size of the conductive particles is reduced, the particles are secondary agglomerated due to a significant increase in the surface area of the conductive particles, and the insulation between the adjacent electrodes cannot be maintained. The problem that the reliability decreases is likely to occur.

  In addition, if the content of the conductive particles is reduced, the number of conductive particles on the electrode also decreases, so the number of contact points is insufficient, and sufficient conduction between the opposing electrodes is obtained, thereby reducing long-term connection reliability. The problem is likely to occur. Thus, with the conventional method, it has been difficult to increase the resolution of the adhesive for circuit connection while maintaining long-term connection reliability.

  In particular, due to the remarkable increase in resolution of circuit boards in recent years, the conductive particles on the electrodes are likely to flow out between adjacent circuit electrodes together with the adhesive due to heating and pressurization at the time of connection. For this reason, the insulation between adjacent electrodes is reduced, the number of conductive particles (number of particles trapped) between the opposing electrodes is reduced, and the electrical conductivity between the opposing electrodes is reduced. This hindered high resolution of the adhesive.

  In order to improve such problems, an adhesive film having a multilayer structure in which the conductive particle-containing layer and the insulating adhesive layer are separated from each other and increasing the number of conductive particles trapped on the electrode to increase the number of conductive particles between adjacent electrodes. Has been proposed (see, for example, Patent Documents 2 to 6).

In addition, in order to realize an adhesive for circuit connection that enables connection of electrodes and circuits that have been miniaturized as described above and that is excellent in connection reliability, a dense state of conductive particles in a necessary portion in the surface direction of the circuit board There has also been proposed a circuit-connecting adhesive formed with (for example, see Patent Document 7).
Japanese Patent Laid-Open No. 03-16147 Japanese Patent Laid-Open No. 01-236588 Japanese Patent Laid-Open No. 02-18809 Japanese Patent Laid-Open No. 04-366630 Japanese Patent Laid-Open No. 08-279371 International Publication No. 2007/123003 JP 2002-76607 A

  However, with the method described in Patent Document 2, the density of the conductive particles on one electrode side is increased, and it is not possible to meet the recent demand for higher resolution. Moreover, when the conductive particle density on one electrode side is increased, the adhesive force at the interface between the electrode and the circuit connecting adhesive is reduced, and interface peeling and connection reliability are liable to occur.

  In addition, in the adhesive for circuit connection described in Patent Documents 3 to 6, a method for suppressing the outflow of conductive particles from the electrodes at the time of connecting circuit members is disclosed. There is still room for improvement in order to provide long-term connection reliability.

  Furthermore, although the adhesive for circuit connection described in Patent Document 7 enables connection between the dot-shaped fine electrodes, the manufacturing method of the adhesive is troublesome, and it is electrically conductive when connecting the electrodes. There is a problem in that workability is inferior because precise alignment of the dense particle area and the electrode is necessary.

  The present invention has been made in view of the above problems, and is capable of high resolution, has excellent long-term connection reliability, and has excellent workability, and a circuit member connection structure using the same And it aims at providing the connection method of a circuit member.

  In order to achieve the above object, the present invention provides a first circuit member in which a first circuit electrode is formed on a main surface of a first substrate, and a second circuit on a main surface of a second substrate. An adhesive film for circuit connection for connecting a second circuit member on which an electrode is formed in a state where the first circuit electrode and the second circuit electrode are arranged to face each other, the conductive particles and the adhesive Conductive adhesive layer containing, insulating first insulating adhesive layer formed on one side of the conductive adhesive, and surface on which the first insulating adhesive layer of the conductive adhesive is formed An insulating second insulative adhesive layer formed on the surface opposite to the surface, and the thickness of the conductive adhesive layer containing the conductive particles and the adhesive is twice the conductive particle size And an adhesive film for circuit connection, wherein the storage elastic modulus at 40 ° C. of the conductive adhesive layer is 0.1 to 1.5 GPa To provide.

  In the adhesive film for circuit connection according to the present invention, the thickness of the conductive adhesive layer is not more than twice the average particle size of the conductive particles, and the storage elastic modulus at 40 ° C. of the conductive adhesive layer is 0.1. By being -1.5 GPa, it is possible to reliably capture a sufficient number of conductive particles between opposing circuit electrodes, and even for minute circuit electrodes, insulation between adjacent circuit electrodes, Sufficient conductivity between the circuit electrodes facing each other can be ensured. Then, by forming an insulating adhesive layer on both sides of the above conductive adhesive layer, the insulating adhesive layer is disposed between adjacent circuit electrodes while maintaining sufficient conductivity, and the opposing circuit The insulation between the electrodes can be further enhanced. For this reason, the adhesive film for circuit connection according to the present invention achieves a high degree of compatibility between the insulation between the adjacent circuit electrodes and the conductivity between the opposing circuit electrodes, and can achieve high resolution. In addition, there is an effect that the long-term connection reliability is excellent. In addition, the adhesive film for circuit connection according to the present invention is excellent in workability at the time of connecting circuit members because accurate alignment between the conductive particles and the electrodes is easy.

  Further, the adhesive film for circuit connection contains a curable resin in which the adhesive is cured by heat or light, the conductive adhesive layer further contains a film-forming polymer, the first insulating adhesive layer and The storage elastic modulus at 40 ° C. of each of the second insulating adhesive layers is less than 0.1 GPa, and at least one of the first insulating adhesive layer and the second insulating adhesive layer The thickness is preferably 0.1 to 5.0 μm. With the above configuration, the film forming property of the conductive adhesive layer can be improved, and the conductive particles can be held in a uniformly dispersed state. Such an adhesive film for circuit connection is excellent in workability because it is easy to accurately position the conductive particles and the circuit electrodes, and is excellent in long-term connection reliability because it is difficult for bubbles to be contained in the connection part. In addition, a sufficient number of conductive particles can be reliably captured, and the insulation between adjacent circuit electrodes and the conductivity between opposing circuit electrodes can be further improved even for a minute circuit electrode. it can.

  Further, the conductive adhesive layer preferably gives a calorific value of 25 to 130 J / g in differential scanning calorimetry and gives a curing reaction rate of 20 to 100% based on the calorific value. . By doing as mentioned above, the storage elastic modulus of the conductive adhesive layer can be easily within a desired range. As a result, a sufficient number of conductive particles can be reliably captured, and even between minute circuit electrodes, the insulation between adjacent circuit electrodes and the conductivity between opposing circuit electrodes can be further improved. Can do.

  In the present invention, the first circuit member in which the first circuit electrode is formed on the main surface of the first substrate and the second circuit electrode on the main surface of the second substrate are formed. A circuit connection member comprising: a second circuit member; and a circuit connection member disposed between the first circuit member and the second circuit member and made of a cured product of the adhesive film for circuit connection according to the present invention. Thus, a circuit member connection structure is provided in which the first circuit electrode and the second circuit electrode are electrically connected in a state of being opposed to each other. In such a circuit member connection structure, since the circuit connection member is made of a cured product of the adhesive film for circuit connection according to the present invention, there is little outflow of conductive particles from the electrode, and a sufficient number of conductive particles are reliably captured. It is possible to sufficiently ensure the insulation between the adjacent circuit electrodes and the conductivity between the opposing circuit electrodes. Therefore, high resolution can be achieved and excellent long-term connection reliability can be achieved.

  Further, in the connection structure of the circuit member, at least one of the first circuit electrode and the second circuit electrode has a circuit electrode height of 3.0 μm or less, the first insulating adhesive layer and the second circuit electrode. The thickness of at least one of the insulating adhesive layers is 0.1 to 5.0 μm, and the thickness of the layer is 0.1 to 5.0 on the circuit electrode side where the height of the circuit electrode is 3.0 μm or less. It is preferable that the insulating adhesive layer which is 5.0 micrometers is arrange | positioned. Such a connection structure of circuit members can further increase the insulation between adjacent circuit electrodes and the conductivity between the opposing circuit electrodes with respect to a minute circuit electrode, and thus has achieved a remarkable increase in resolution in recent years. The requirements can be met at a high level.

  The present invention also provides a first circuit member in which a first circuit electrode is formed on a main surface of a first substrate, and a second circuit electrode in which a second circuit electrode is formed on a main surface of a second substrate. The second circuit member is disposed between the first circuit member and the second circuit member, and the first circuit electrode and the second circuit electrode face each other, the adhesive film for circuit connection according to the present invention. Provided is a circuit member connection method in which a first circuit electrode and a second circuit electrode are electrically connected by heating and pressurizing in the arranged state. According to such a circuit member connection method, by using the circuit connection adhesive film according to the present invention, it is possible to reliably capture a sufficient number of conductive particles by suppressing the outflow of the conductive particles from the electrode. Insulation between adjacent circuit electrodes and conductivity between opposing circuit electrodes can be sufficiently ensured. For this reason, it is possible to increase the resolution and form a circuit member connection structure with excellent long-term connection reliability.

  Furthermore, the circuit member connection method is such that at least one of the first circuit electrode and the second circuit electrode has a height of 3.0 μm or less, the first insulating adhesive layer and the second circuit electrode. The thickness of at least one of the insulating adhesive layers is 0.1 to 5.0 μm, and the thickness of the layer is 0.1 to 5.0 on the circuit electrode side where the height of the circuit electrode is 3.0 μm or less. The first circuit member and the second circuit electrode are electrically connected to each other by arranging and heating and pressurizing the insulating adhesive layer having a thickness of 5.0 μm. It is preferable to connect the circuit member. According to such a method for connecting circuit members, the insulation between the adjacent circuit electrodes and the conductivity between the facing circuit electrodes can be further enhanced with respect to the minute circuit electrodes, and thus the remarkably high resolution in recent years. Therefore, it is possible to form a connection structure for circuit members that can achieve the demand for a high level of performance.

  According to the present invention, it is possible to reliably capture a sufficient number of conductive particles between opposing circuit electrodes, and sufficiently ensure insulation between adjacent circuit electrodes and conductivity between opposing circuit electrodes. Therefore, it is possible to achieve high resolution, excellent long-term connection reliability, and easy alignment of the conductive particles and the circuit electrodes. It is possible to provide a circuit member connection structure and a circuit member connection method using the circuit board.

  The best mode for carrying out the invention will be described below in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  FIG. 1 is a schematic cross-sectional view showing a preferred embodiment of an adhesive film for circuit connection (anisotropic conductive adhesive film) according to the present invention. An adhesive film 100 for circuit connection shown in FIG. 1 includes a conductive adhesive layer 3 including conductive particles 1 and an adhesive 2, and an insulating insulating adhesive layer 4 formed on both surfaces of the conductive adhesive layer 3. , 5 (first and second insulating adhesive layers). Although not shown in FIG. 1, a peelable base material (support film) is present on the surface of the circuit connecting adhesive film 100 in order to improve workability and prevent dust adhesion. Also good.

  Hereinafter, the adhesive film 100 for circuit connection shown in FIG. 1 is used and each layer which comprises the adhesive film 100 for circuit connection is demonstrated in detail.

  The conductive adhesive layer 3 is a layer containing the conductive particles 1 and the adhesive 2 as described above. When the circuit members having circuit electrodes are connected to each other, the conductive adhesive layer 3 is conductive in the direction connecting the opposing circuit electrodes. This is a layer having anisotropic conductivity and capable of electrically connecting only the facing circuit electrodes.

  Here, the adhesive 2 preferably contains a reactive resin (curable resin) that is cured by heat or light. As the curable resin, a mixture of epoxy resin and latent curing agent such as imidazole, hydrazide, boron trifluoride-amine complex, sulfonium salt, amine imide, polyamine salt, dicyandiamide, or radical reactive resin And a mixture of organic peroxide and the like.

  Examples of the epoxy resin include bisphenol type epoxy resins derived from epichlorohydrin and bisphenol A, bisphenol F, bisphenol AD, and the like, epoxy novolac resins derived from epichlorohydrin and phenol novolac and cresol novolac, and naphthalene having a skeleton containing a naphthalene ring. Various epoxy compounds having two or more glycidyl groups in one molecule such as epoxy resin, glycidylamine, glycidyl ether, biphenyl, and alicyclic can be used alone or in admixture of two or more. is there.

For these epoxy resins, it is preferable to use a high-purity product in which the content of impurity ions (Na ⁺ , Cl ^−, etc.) and hydrolyzable chlorine is reduced to 300 ppm or less, from the viewpoint of preventing electron migration.

  The conductive particles 1 are mixed in the conductive adhesive layer 3 for the purpose of absorbing unevenness in the heights of the bumps and substrate electrodes of the chips connected by the circuit connecting adhesive film 100 and positively imparting anisotropic conductivity.・ Dispersed.

  The conductive particles 1 are conductive particles containing a metal such as Au, Ag, Ni, Cu, and solder, for example. On the surface of a spherical core material made of a polymer such as polystyrene, Au, Ag, Ni, Cu The particles are preferably formed by forming a conductive layer made of a metal such as solder. The conductive particles 1 may be formed by further forming a surface layer such as Au or solder on the outer peripheral side of the conductive layer.

  The average particle diameter of the conductive particles 1 needs to be smaller than the minimum interval between the electrodes of the circuit members connected by the circuit connecting adhesive film 100, and when there is a variation in the height of the circuit electrodes, It is preferable that it is larger than the variation in thickness. The average particle diameter of the conductive particles 1 is preferably 1 to 10 μm, and more preferably 2 to 5 μm. If the average particle size is less than 1 μm, the electrical conductivity between the circuit electrodes tends to decrease without being able to cope with the variation in the height of the circuit electrodes, and if it exceeds 10 μm, the insulation between adjacent circuit electrodes is poor. It tends to decrease.

  In the present invention, “average particle diameter” means a value measured as follows. That is, the primary particles of arbitrarily selected conductive particles 1 were observed with a scanning electron microscope (SEM, manufactured by Hitachi, Ltd., trade name: S-800) (magnification: 5000 times), and the maximum diameter and the maximum diameter were observed. Measure the small diameter. The square root of the product of the maximum diameter and the minimum diameter is defined as the primary particle diameter of the particle. Then, the primary particle diameter is measured as described above for 50 arbitrarily selected conductive particles, and the average value is defined as the average particle diameter.

  The conductive adhesive layer 3 has a thickness of not more than twice the average particle diameter of the conductive particles 1 and a modulus of elasticity at 40 ° C. of 0.1 to 1.5 GPa when the circuit members are connected to each other. It is required to be within range. When the thickness of the conductive adhesive layer 3 is not more than twice the average particle diameter and the storage elastic modulus at 40 ° C. is 0.1 to 1.5 GPa, the conductive particles are bonded by pressurization at the time of connection. It is possible to reduce outflow between adjacent circuit electrodes together with the agent, and thereby, it is possible to reliably capture a sufficient number of conductive particles, and even between minute circuit electrodes, between adjacent circuit electrodes. Insulation and electrical conductivity between circuit electrodes facing each other can be sufficiently ensured. In addition, the storage elastic modulus of the conductive adhesive layer 3 can be measured by, for example, a viscoelasticity measuring device (manufactured by Rheometrics, trade name: RSAII, heating rate: 10 ° C./min, frequency: 1 Hz). .

  When the thickness of the conductive adhesive layer 3 exceeds twice the average particle diameter, or the storage elastic modulus at 40 ° C. of the conductive adhesive layer 3 is less than 0.1 GPa, the conductive adhesive layer 3 is electrically conductive by pressurization at the time of connection. There is a tendency for the number of particles to flow out between adjacent circuit electrodes with the adhesive, thereby reducing the number of conductive particles that can be captured. On the other hand, if it exceeds 1.5 GPa, there is a tendency that sufficient conductivity between the facing circuit electrodes cannot be ensured.

  The conductive adhesive layer 3 preferably provides a calorific value of 25 to 130 J / g based on the curing reaction in DSC. This calorific value is calculated as follows, for example, by measuring in the temperature range of 25 ° C. to 200 ° C. at a temperature rising rate of 10 ° C./min using a product name: DSC1000 manufactured by TA Instrument as DSC. The

  The curing reaction of the conductive adhesive layer 3 is an exothermic reaction, and when the sample is heated at a constant temperature increase rate using DSC, the sample reacts to generate heat. The calorific value is output to a chart, and the area surrounded by the heat generation curve and the baseline is obtained based on the baseline (a straight line passing through the measurement start point and approximately parallel to the temperature axis (horizontal axis)). Amount. When the heating value exceeds 130 J / g, the internal stress increases due to an increase in the curing shrinkage force and storage elastic modulus of the adhesive, and when the circuits are connected to each other, the circuit boards warp, reducing the connection reliability and electronic components. This causes a problem that causes deterioration of characteristics. On the other hand, when the calorific value is less than 25 J / g, there is a problem that the curability of the adhesive is insufficient and the adhesiveness and connection reliability are lowered.

  In addition, the conductive adhesive layer 3 gives a reaction rate of 20 to 100% of the curing reaction based on the above-described calorific value given as 25 to 130 J / g in DSC, that is, 20 to 100% of the curing reaction. It is preferable that it is completed. The reaction rate of the conductive adhesive layer 3 can be calculated as follows, for example.

First, the calorific value of the conductive adhesive layer 3 is obtained using DSC. Next, the calorific value of the conductive adhesive layer 3i produced by drying with hot air under the condition below the activation temperature of the curing agent using the same coating liquid for forming the conductive adhesive layer as that of the conductive adhesive layer 3 is calculated by DSC. Use to find. From these calorific values, the reaction rate can be obtained from the following equation.
Reaction rate = (heat generation amount of the conductive adhesive layer 3i−heat generation amount of the conductive adhesive layer 3) / heat generation amount of the conductive adhesive layer 3i × 100

  The content of the conductive particles 1 in the conductive adhesive layer 3 is preferably 0.1 to 40% by volume based on the total volume of the solid content in the conductive adhesive layer 3, and is preferably 0.2 to 30%. More preferably, it is volume%. If this content is less than 0.1% by volume, the number of conductive particles on the opposing circuit electrodes will decrease, so the number of contact points will be insufficient, and the conductivity between the circuit electrodes will tend to decrease, If it exceeds 40% by volume, the conductive particles tend to be agglomerated due to a significant increase in the surface area of the particles and easily connected, and the insulation between adjacent circuit electrodes tends to decrease.

The insulating adhesive layers 4 and 5 constituting the circuit connecting adhesive film 100 are insulating layers. When the insulating adhesive layers 4 and 5 are disposed between adjacent circuit electrodes in the circuit member, the insulating adhesive layers 4 and 5 sufficiently ensure insulation between the adjacent circuit electrodes (preferably, insulation between adjacent circuit electrodes). The composition is not particularly limited as long as the resistance value can be 1 × 10 ⁸ Ω or more). For example, the composition is the same as that obtained by removing the conductive particles 1 from the conductive adhesive layer 3 described above. The composition can be

  The thickness of at least one of the insulating adhesive layers 4 and 5 is preferably 0.1 to 5.0 μm when connected through the conductive adhesive layer 3, and is preferably 1.0 to 4 μm. More preferably, it is 0.0 μm. When the thickness is less than 0.1 μm, when the insulating adhesive layer flows between adjacent circuit electrodes in the circuit member, sufficient insulation cannot be secured between the adjacent circuit electrodes. If it exceeds, the outflow of the conductive particles from the electrodes increases, and it is impossible to sufficiently secure the insulation between the adjacent circuit electrodes and the conductivity between the opposing circuit electrodes.

  The thickness of at least one of the insulating adhesive layers 4 and 5 is formed on the first circuit electrode thickness formed on the main surface of the first substrate and on the main surface of the second substrate. It is preferable that the total thickness is equal to or less than the total thickness of the second circuit electrode. If the thickness of the circuit electrode is larger than the sum of the thickness of the first circuit electrode and the thickness of the second circuit electrode, the amount of conductive particles flowing out from the electrode increases, and the insulation between adjacent electrodes and the opposite It tends to be difficult to ensure sufficient electrical conductivity between circuit electrodes.

  Further, in the adhesive film for circuit connection 100, the storage elastic modulus of the insulating adhesive layers 4 and 5 at 40 ° C. is preferably lower than that of the conductive adhesive layer 3, and more preferably less than 0.1 GPa. preferable. When the storage elastic modulus at 40 ° C. of the insulating adhesive layers 4 and 5 is 0.1 GPa or more, the outflow of conductive particles from the electrodes increases, and the insulation between adjacent circuit electrodes and the opposing circuit electrodes There is a tendency that it is difficult to ensure sufficient electrical conductivity.

  The conductive adhesive layer 3 and the insulating adhesive layers 4 and 5 may be blended with a film-forming polymer from the viewpoint of improving the film-forming property. Examples of the film-forming polymer include thermoplastic resins such as phenoxy resin, polyester resin, and polyamide resin. These film-forming polymers are effective for stress relaxation during curing of the curable resin. In particular, when the film-forming polymer has a functional group such as a hydroxyl group, the adhesiveness is improved, which is more preferable.

  In addition, inorganic fillers and rubber particles can be further mixed and dispersed in the conductive adhesive layer 3 and the insulating adhesive layers 4 and 5. These can be mixed and dispersed in the conductive adhesive layer 3 together with the conductive particles 1 and can also be mixed and dispersed in the insulating adhesive layers 4 and 5 where the conductive particles 1 are not used. It is preferable to mix and disperse in the conductive adhesive layer 3 using By adding these inorganic fillers and rubber particles to the conductive adhesive layer 3, the storage elastic modulus at 40 ° C. of the conductive adhesive layer 3 can be easily within a desired range.

  The inorganic filler is not particularly limited, and examples thereof include powders such as fused silica, crystalline silica, calcium silicate, alumina, and calcium carbonate. The average particle size of the inorganic filler is preferably 3 μm or less from the viewpoint of preventing poor conduction at the connection portion.

  The amount of the inorganic filler is preferably 5 to 100 parts by mass with respect to 100 parts by mass of the adhesive 2 in any of the conductive adhesive layer 3 and the insulating adhesive layers 4 and 5. .

  The rubber particles are not particularly limited as long as the glass particles have a glass transition temperature of 25 ° C. or lower. For example, butadiene rubber, acrylic rubber, styrene-butadiene-styrene rubber, nitrile-butadiene rubber, silicone rubber, or the like is used. Can do.

  As the rubber particles, those having an average particle size of 0.1 to 10 μm are preferably used, and rubber particles in which particles having an average particle size or less occupy 80% or more of the particle size distribution are more preferable. The average particle size of the rubber particles is more preferably 0.1 to 5 μm. Moreover, when the surface of a rubber particle is processed with a silane coupling agent, since the dispersibility with respect to curable resin improves, it is more preferable.

  Among the rubber particles, the silicone rubber particles can be used as effective rubber particles because they are excellent in solvent resistance and dispersibility. Silicone rubber particles are hydrolyzed and polycondensed by adding a silane compound and methyltrialkoxysilane and / or a partially hydrolyzed condensate thereof to an aqueous alcohol solution adjusted to pH 9 or higher with a basic substance such as caustic soda or ammonia. Or a copolymerization of organosiloxane.

  Silicone rubber particles containing a functional group such as a hydroxyl group, an epoxy group, a ketimine, a carboxyl group, or a mercapto group at the molecular terminal or inner molecular chain are preferable because dispersibility in a curable resin is improved.

  The compounding amount of the rubber particles is preferably 5 to 50 parts by mass with respect to 100 parts by mass of the adhesive 2 in any of the conductive adhesive layer 3 and the insulating adhesive layers 4 and 5.

  Formation of the conductive adhesive layer 3 and the insulating adhesive layers 4 and 5 includes at least the adhesive 2, and the conductive adhesive layer 3 further dissolves an adhesive composition including the conductive particles 1 in an organic solvent. Alternatively, it can be carried out by preparing a coating solution by liquefying by dispersing, coating the coating solution on a peelable substrate (support film), and removing the solvent below the activation temperature of the curing agent.

  The solvent used at this time is preferably a mixed solvent of an aromatic hydrocarbon solvent and an oxygen-containing solvent from the viewpoint of improving the solubility of the material. Moreover, as a peelable base material, a PET film or the like surface-treated so as to have releasability is preferably used.

  Moreover, about formation of the conductive adhesive layer 3, after adjusting a coating liquid, this coating liquid is apply | coated on a peelable base material (support film), and a solvent is removed on the conditions beyond the active temperature of a hardening | curing agent. Can also be done. The conductive adhesive layer 3 formed at this time gives a calorific value of 25 to 130 J / g in the DSC as described above, and gives a curing reaction rate of 20 to 100% based on the calorific value. It is preferable that

  Although not shown, a conductive adhesive layer or an insulating adhesive layer can be further provided outside the insulating adhesive layers 4 and 5.

  And as a manufacturing method of the adhesive film 100 for circuit connection, the method of laminating | stacking the conductive adhesive layer 3 and the insulating adhesive layers 4 and 5 which were formed as mentioned above, and the method of coating each layer sequentially, for example A known method such as the above can be employed.

  Next, a circuit member connection structure using the circuit connection adhesive film 100 according to the present invention will be described.

  FIG. 2 is a schematic cross-sectional view showing a preferred embodiment of a circuit member connection structure according to the present invention. The circuit member connection structure 200 shown in FIG. 2 includes a first circuit member 10 having a first circuit electrode 12 formed on the first substrate 11 and its main surface, a second substrate 21 and its main substrate. The second circuit member 20 having the second circuit electrode 22 formed on the surface is made of a cured product obtained by curing the circuit connecting adhesive film 100 of the present invention, and the first and second circuit members 10, Are connected by a circuit connecting member 100a formed between the two. In the circuit member connection structure 200, the first circuit electrode 12 and the second circuit electrode 22 are electrically connected in a state of being opposed to each other.

  The circuit connection member 100a is made of a cured product obtained by curing the adhesive film for circuit connection 100 according to the present invention, and includes the cured product 2a of the adhesive 2 and the conductive particles 1 dispersed therein. It is comprised from the hardened | cured material 3a of the adhesive bond layer 3, and the hardened | cured materials 4a and 5a of the insulating adhesive layers 4 and 5 formed in the both surfaces. The first circuit electrode 12 and the second circuit electrode 22 are electrically connected via the conductive particles 1.

  The cured products 4a and 5a of the insulating adhesive layers 4 and 5 are formed so as to cover at least the first and second substrates 11 and 21 around the first and second circuit electrodes 12 and 22, respectively. Has been. This is because when the first and second circuit members 10 and 20 are connected, the insulating adhesive layers 4 and 5 are on the first and second circuit electrodes 12 and 22 (on the surfaces facing each other), This is because it flows out to the surroundings.

  At least one of the height h1 of the first circuit electrode 12 and the height h2 of the second circuit electrode 22 is preferably 3.0 μm or less. When the thickness of at least one of the insulating adhesive layers 4 and 5 is 0.1 to 5.0 μm, the insulating adhesive layer having a thickness of 0.1 to 5.0 μm It is preferable that the electrode is disposed on the circuit electrode side having a height of 3.0 μm or less.

The first and second circuit members 10 and 20 are not particularly limited as long as electrodes that require electrical connection are formed. Specific examples include glass or plastic substrates with electrodes formed of ITO or the like used for liquid crystal displays, printed wiring boards, ceramic wiring boards, flexible wiring boards, semiconductor silicon chips, and the like. Used in combination accordingly. As described above, in this embodiment, a printed wiring board, a material made of an organic material such as polyimide, a metal such as copper or aluminum, ITO (indium tin oxide), silicon nitride (SiN _x ), silicon dioxide (SiO ₂ ). Circuit members having various surface states such as inorganic materials such as) can be used.

  The circuit member connection structure 200 includes a first circuit member 10 in which the first circuit electrode 12 is formed on the main surface of the first substrate 11 and a second circuit on the main surface of the second substrate 21. The second circuit member 20 on which the electrode 22 is formed and the first circuit member 10 and the second circuit member 20 are arranged between the first circuit member 10 and the circuit connection adhesive film 100 according to the present invention. It is obtained by a method of electrically connecting the first circuit electrode 12 and the second circuit electrode 22 by heating and pressurizing the electrode 12 and the second circuit electrode 22 facing each other.

  In this method, the circuit connection adhesive film 100 is temporarily pressure-bonded by heating and pressurizing the circuit connection adhesive film 100 formed on the peelable substrate on the second circuit member 20. Then, after peeling off the peelable substrate, the first circuit member 10 is placed while aligning the circuit electrodes, and then heated and pressurized to form the second circuit member 20, the circuit connecting adhesive film 100, and the first A laminate in which one circuit member 10 is laminated in this order can be prepared.

  Conditions for heating and pressurizing the laminate are appropriately adjusted according to the curability of the adhesive in the circuit connection adhesive film so that the circuit connection adhesive film is cured and sufficient adhesive strength is obtained. The

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not restrict | limited to a following example.

Example 1
Phenoxy resin (Union Carbide, trade name: PKHC) 32 parts by mass, bisphenol A epoxy resin having an average particle diameter of 0.2 μm dispersed in 20% by mass of acrylic particle-containing resin (manufactured by Nippon Shokubai Co., Ltd., Product name: BPA 328) 10 parts by mass, bisphenol A type solid epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd., product name: YL980), 20 parts by mass, imidazole-based curing agent (manufactured by Asahi Kasei Kogyo Co., Ltd., trade name: Novacure HX-3941) 35 parts by mass and 3 parts by mass of a silane coupling agent (trade name: A187, manufactured by Nippon Unicar Co., Ltd.) were dissolved in toluene as a solvent to obtain a coating liquid for forming an insulating adhesive layer having a solid content of 50% by mass.

  Next, this coating solution is applied to a 50 μm-thick PET film having a release treatment (medium release treatment) on one side (the surface to which the coating solution is applied), and a product name (trade name, manufactured by Yasui Seiki Co., Ltd.). Was coated using a precision coating machine, and dried with hot air at 70 ° C. for 10 minutes to form an insulating adhesive layer (a) having a thickness of 15 μm on the PET film. When the storage elastic modulus of this insulating adhesive layer (a) was measured at a temperature rising rate of 10 ° C./min and a frequency of 1 Hz using a viscoelasticity measuring apparatus (trade name: RSAII, manufactured by Rheometrics), 40 The storage elastic modulus at 0 ° C. was 0.05 GPa.

  Furthermore, the coating liquid for forming the insulating adhesive layer was applied to a PET film having a thickness of 25 μm, on which one side (the surface on which the coating liquid was applied) was subjected to a release treatment (light release treatment), using a coating apparatus. The insulating adhesive layer (b) having a thickness of 2 μm was formed on the PET film by drying with hot air at 70 ° C. for 10 minutes. When the storage elastic modulus of this insulating adhesive layer (b) was measured at a rate of temperature increase of 10 ° C./min and a frequency of 1 Hz using a viscoelasticity measuring device, the storage elastic modulus at 40 ° C. was 0.05 GPa. there were.

  Next, an acrylic particle-containing resin (Nippon Catalyst Co., Ltd.) in which 20% by mass of acrylic particles having an average particle size of 0.2 μm are dispersed in 60 parts by mass of a phenoxy resin (manufactured by Union Carbide, trade name: PKHC) and a bisphenol A type epoxy resin. 12 parts by mass, product name: BPA 328), 16 parts by mass of imidazole curing agent (manufactured by Asahi Kasei Kogyo Co., Ltd., trade name: Novacure HX-3941), silane coupling agent (trade name: A187, Nihon Unicar) Part by mass and 10 parts by mass of silicone rubber (trade name: EP2100, manufactured by Toray Dow Corning) were dissolved in toluene as a solvent to prepare an adhesive solution having a solid content of 50% by mass.

  In 100 parts by mass of this adhesive solution, 35 parts by mass of conductive particles (average particle size: 3 μm) in which a Ni layer and an outer Au layer are formed on the surface of a polystyrene core (diameter: 2.8 μm) are dispersed. Thus, a coating solution for forming a conductive adhesive layer was obtained.

  This coating solution is applied to a 50 μm-thick PET film having a release treatment (light release treatment) on one side (surface to which the coating solution is applied), and a coating device (trade name: Precision, manufactured by Yasui Seiki Co., Ltd.). Was applied using a coating machine) and dried with hot air at 70 ° C. for 10 minutes to form a 6 μm thick conductive adhesive layer (c) on the PET film. When the calorific value of this conductive adhesive layer (c) was measured from 25 ° C. to 200 ° C. at a heating rate of 10 ° C./min using DSC (trade name: DSC1000, manufactured by TA Instruments), the calorific value was 80 J / G.

When the storage elastic modulus of this conductive adhesive layer (c) was measured at a rate of temperature increase of 10 ° C./min and a frequency of 1 Hz using a viscoelasticity measuring device, the storage elastic modulus at 40 ° C. was 0.1 GPa. there were.

  The insulating adhesive layer (a) and conductive adhesive layer (c) obtained above were laminated with a roll laminator while heating at 50 ° C. to obtain a laminated film. Subsequently, after peeling off the PET film on the conductive adhesive layer (c) on the conductive adhesive layer (c) side of the obtained laminated film, the insulating adhesive layer (b) obtained above is applied. Laminating with a roll laminator while heating at 50 ° C., the thickness of the insulating adhesive layer (a) is 15 μm, the thickness of the conductive adhesive layer (c) is 6 μm, and the thickness of the insulating adhesive layer (b) Obtained an adhesive film for circuit connection having a 3-layer structure of 2 μm.

(Example 2)
Example 1 except that the thickness of the insulating adhesive layer (a) was 18 μm, the thickness of the insulating adhesive layer (b) was 2 μm, and the thickness of the conductive adhesive layer (c) was 3 μm. Through this process, an adhesive film for circuit connection having a three-layer structure was obtained.

(Example 3)
Acrylic particle-containing resin (manufactured by Nippon Shokubai Co., Ltd.) in which 32 mass parts of phenoxy resin (manufactured by Union Carbide, trade name: PKHC), 20 mass% of acrylic particles having an average particle diameter of 0.2 μm are dispersed in bisfer A type epoxy resin , Trade name: BPA328) 10 parts by mass, bisphenol A type solid epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd., trade name: YL980), imidazole curing agent (manufactured by Asahi Kasei Kogyo Co., Ltd., trade name: Novacure HX-3941) ) 35 parts by mass and 3 parts by mass of a silane coupling agent (manufactured by Nippon Unicar Co., Ltd., trade name: A187) were dissolved in toluene as a solvent to obtain a coating liquid for forming an insulating adhesive layer having a solid content of 50% by mass. .

  Next, this coating solution is applied to a PET film having a thickness of 50 μm on one side (the surface to which the coating solution is applied) using a coating apparatus, and dried with hot air at 70 ° C. for 10 minutes, An insulating adhesive layer (a) having a thickness of 18 μm was formed on the PET film. When the storage elastic modulus of this insulating adhesive layer (a) was measured at a rate of temperature increase of 10 ° C./min and a frequency of 1 Hz using a viscoelasticity measuring device, the storage elastic modulus at 40 ° C. was 0.05 GPa. there were.

  Further, the above coating solution for forming an insulating adhesive layer was applied to a PET film having a thickness of 25 μm, on which one side (the surface on which the coating solution was applied), was applied using a coating apparatus, and the coating solution was applied at 70 ° C. The insulating adhesive layer (b) having a thickness of 2 μm was formed on the PET film by drying with hot air for a minute. When the storage elastic modulus of this insulating adhesive layer (b) was measured using a viscoelasticity measuring device at a heating rate of 10 ° C./min and a frequency of 1 Hz, the storage elastic modulus at 40 ° C. was 0.05 GPa. It was.

  Next, an acrylic particle-containing resin (Nippon Catalyst Co., Ltd.) in which 20% by mass of acrylic particles having an average particle size of 0.2 μm are dispersed in 60 parts by mass of a phenoxy resin (manufactured by Union Carbide, trade name: PKHC) and a bisphenol A type epoxy resin. 12 parts by mass, trade name: BPA 328), 16 parts by mass of imidazole-based curing agent (manufactured by Asahi Kasei Kogyo Co., Ltd., trade name: Novacure HX-3941), 2 parts by mass of silane coupling agent (A187, manufactured by Nihon Unicar) and silicone 10 parts by mass of rubber (trade name: EP2100, manufactured by Toray Dow Corning Co., Ltd.) was dissolved in toluene as a solvent to prepare an adhesive solution having a solid content of 50% by mass.

  To 100 parts by mass of this adhesive solution, 35 parts by mass of conductive particles (average particle diameter: 3 μm) in which a Ni layer and an Au layer are formed on the outer peripheral side on the surface of a polystyrene core (diameter: 2.8 μm) Dispersed to obtain a coating solution for forming a conductive adhesive layer.

  This coating solution is applied to a PET film having a thickness of 50 μm on one side (the surface to which the coating solution is applied) using a coating apparatus, and then dried with hot air at 70 ° C. for 10 minutes, whereby PET film A conductive adhesive layer (c) having a thickness of 3 μm was formed thereon. When the calorific value of this conductive adhesive layer (c) was measured from 25 ° C. to 200 ° C. at a rate of temperature rise of 10 ° C./min using DSC, the calorific value was 80 J / g.

  The conductive adhesive layer (c) obtained above was dried with hot air at 100 ° C. for 30 minutes to obtain a conductive adhesive layer (c) in which 30% of the curing reaction was completed. When the storage elastic modulus of this conductive adhesive layer (c) was measured at a rate of temperature increase of 10 ° C./min and a frequency of 1 Hz using a viscoelasticity measuring device, the storage elastic modulus at 40 ° C. was 0.5 GPa. there were.

  The insulating adhesive layer (a) and conductive adhesive layer (c) obtained above were laminated with a roll laminator while heating at 50 ° C. to obtain a laminated film. Subsequently, after peeling off the PET film on the conductive adhesive layer (c) on the conductive adhesive layer (c) side of the obtained laminated film, the insulating adhesive layer (b) obtained above is applied. Laminating with a roll laminator while heating at 50 ° C., the thickness of the insulating adhesive layer (a) is 18 μm, the thickness of the conductive adhesive layer (c) is 3 μm, and the thickness of the insulating adhesive layer (b) Obtained an adhesive film for circuit connection having a 3-layer structure of 2 μm.

Example 4
Phenoxy resin (Union Carbide, trade name: PKHC) 32 parts by mass, bisphenol A epoxy resin having an average particle diameter of 0.2 μm dispersed in 20% by mass of acrylic particle-containing resin (manufactured by Nippon Shokubai Co., Ltd., Product name: BPA 328) 10 parts by mass, bisphenol A type solid epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd., product name: YL980), 20 parts by mass, imidazole-based curing agent (manufactured by Asahi Kasei Kogyo Co., Ltd., trade name: Novacure HX-3941) 35 parts by mass and 3 parts by mass of a silane coupling agent (trade name: A187, manufactured by Nippon Unicar Co., Ltd.) were dissolved in toluene as a solvent to obtain a coating liquid for forming an insulating adhesive layer having a solid content of 50% by mass.

  Next, this coating solution is applied to a PET film having a thickness of 50 μm on one side (the surface to which the coating solution is applied) using a coating apparatus, and dried with hot air at 70 ° C. for 10 minutes, An insulating adhesive layer (a) having a thickness of 18 μm was formed on the PET film. When the storage elastic modulus of this insulating adhesive layer (a) was measured at a rate of temperature increase of 10 ° C./min and a frequency of 1 Hz using a viscoelasticity measuring device, the storage elastic modulus at 40 ° C. was 0.05 GPa. there were.

  Further, the above coating solution for forming an insulating adhesive layer was applied to a PET film having a thickness of 25 μm, on which one side (the surface on which the coating solution was applied), was applied using a coating apparatus, and the coating solution was applied at 70 ° C. The insulating adhesive layer (b) having a thickness of 2 μm was formed on the PET film by drying with hot air for a minute. When the storage elastic modulus of this insulating adhesive layer (b) was measured at a rate of temperature increase of 10 ° C./min and a frequency of 1 Hz using a viscoelasticity measuring device, the storage elastic modulus at 40 ° C. was 0.05 GPa. there were.

  Next, an acrylic particle-containing resin (Nippon Catalyst Co., Ltd.) in which 20% by mass of acrylic particles having an average particle size of 0.2 μm are dispersed in 60 parts by mass of a phenoxy resin (manufactured by Union Carbide, trade name: PKHC) and a bisphenol A type epoxy resin. 12 parts by mass, product name: BPA 328), 16 parts by mass of imidazole curing agent (manufactured by Asahi Kasei Kogyo Co., Ltd., trade name: Novacure HX-3941), silane coupling agent (trade name: A187, Nihon Unicar) Part by mass and 10 parts by mass of silicone rubber (trade name: EP2100, manufactured by Toray Dow Corning) were dissolved in toluene as a solvent to prepare an adhesive solution having a solid content of 50% by mass.

  To 100 parts by mass of this adhesive solution, 35 parts by mass of conductive particles (average particle diameter: 3 μm) in which a Ni layer and an Au layer are formed on the outer peripheral side on the surface of a polystyrene core (diameter: 2.8 μm) Dispersed to obtain a coating solution for forming a conductive adhesive layer.

  This coating solution is applied to a PET film having a thickness of 50 μm on one side (the surface to which the coating solution is applied) using a coating apparatus, and then dried with hot air at 70 ° C. for 10 minutes, whereby PET film A conductive adhesive layer (c) having a thickness of 3 μm was formed thereon. When the calorific value of this conductive adhesive layer (c) was measured from 25 ° C. to 200 ° C. at a heating rate of 10 ° C./min using DSC, the calorific value was 80 J / g.

  The conductive adhesive layer (c) obtained above was dried with hot air at 150 ° C. for 30 minutes to obtain a conductive adhesive layer (c) in which 100% of the curing reaction was completed. When the storage elastic modulus of this conductive adhesive layer (c) was measured at a rate of temperature increase of 10 ° C./min and a frequency of 1 Hz using a viscoelasticity measuring device, the storage elastic modulus at 40 ° C. was 1.4 GPa. there were.

  The insulating adhesive layer (a) and conductive adhesive layer (c) obtained above were laminated with a roll laminator while heating at 50 ° C. to obtain a laminated film. Subsequently, after peeling off the PET film on the conductive adhesive layer (c) on the conductive adhesive layer (c) side of the obtained laminated film, the insulating adhesive layer (b) obtained above is applied. Laminating with a roll laminator while heating at 50 ° C., the thickness of the insulating adhesive layer (a) is 18 μm, the thickness of the conductive adhesive layer (c) is 3 μm, and the thickness of the insulating adhesive layer (b) Obtained an adhesive film for circuit connection having a 3-layer structure of 2 μm.

(Comparative Example 1)
Example 1 except that the thickness of the insulating adhesive layer (a) was 13 μm, the thickness of the insulating adhesive layer (b) was 2 μm, and the thickness of the conductive adhesive layer (c) was 8 μm. Through this process, an adhesive film for circuit connection having a three-layer structure was obtained.

(Comparative Example 2)
Example 4 except that the thickness of the insulating adhesive layer (a) was 13 μm, the thickness of the insulating adhesive layer (b) was 2 μm, and the thickness of the conductive adhesive layer (c) was 8 μm. Through this process, an adhesive film for circuit connection having a three-layer structure was obtained.

(Comparative Example 3)
Phenoxy resin (Union Carbide, trade name: PKHC) 32 parts by mass, bisphenol A epoxy resin having an average particle diameter of 0.2 μm dispersed in 20% by mass of acrylic particle-containing resin (manufactured by Nippon Shokubai Co., Ltd., Product name: BPA 328) 10 parts by mass, bisphenol A type solid epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd., product name: YL980), 20 parts by mass, imidazole-based curing agent (manufactured by Asahi Kasei Kogyo Co., Ltd., trade name: Novacure HX-3941) 35 parts by mass and 3 parts by mass of a silane coupling agent (trade name: A187, manufactured by Nippon Unicar Co., Ltd.) were dissolved in toluene as a solvent to obtain a coating liquid for forming an insulating adhesive layer having a solid content of 50% by mass.

  Next, this coating solution is applied to a PET film having a thickness of 50 μm on one side (the surface to which the coating solution is applied) using a coating apparatus, and dried with hot air at 70 ° C. for 10 minutes, An insulating adhesive layer (a) having a thickness of 15 μm was formed on the PET film. When the storage elastic modulus of this insulating adhesive layer (a) was measured at a rate of temperature increase of 10 ° C./min and a frequency of 1 Hz using a viscoelasticity measuring device, the storage elastic modulus at 40 ° C. was 0.05 GPa. there were.

  Further, the above coating solution for forming an insulating adhesive layer was applied to a PET film having a thickness of 25 μm, on which one side (the surface on which the coating solution was applied), was applied using a coating apparatus, and the coating solution was applied at 70 ° C. The insulating adhesive layer (b) having a thickness of 2 μm was formed on the PET film by drying with hot air for a minute. When the storage elastic modulus of this insulating adhesive layer (b) was measured at a rate of temperature increase of 10 ° C./min and a frequency of 1 Hz using a viscoelasticity measuring device, the storage elastic modulus at 40 ° C. was 0.05 GPa. there were.

  Next, 32 parts by mass of phenoxy resin (trade name: PKHC, manufactured by Union Carbide), an acrylic particle-containing resin (Nippon Catalyst Co., Ltd.) in which 20% by mass of acrylic particles having an average particle size of 0.2 μm are dispersed in a bisphenol A type epoxy resin. Product name: BPA328) 10 parts by mass, bisphenol A type solid epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd., product name: YL980), 20 parts by mass, imidazole curing agent (Asahi Kasei Kogyo Co., Ltd., product name: NovaCure HX) -3941) 35 parts by mass and 3 parts by mass of a silane coupling agent (manufactured by Nihon Unicar Co., Ltd., trade name: A187) were dissolved in toluene as a solvent to prepare an adhesive solution having a solid content of 50% by mass.

  To 100 parts by mass of this adhesive solution, 35 parts by mass of conductive particles (average particle diameter: 3 μm) in which a Ni layer and an Au layer are formed on the outer peripheral side on the surface of a polystyrene core (diameter: 2.8 μm) Dispersed to obtain a coating solution for forming a conductive adhesive layer.

  This coating solution is applied to a PET film having a thickness of 50 μm on one side (the surface to which the coating solution is applied) using a coating apparatus, and then dried with hot air at 70 ° C. for 10 minutes, whereby PET film A conductive adhesive layer (c) having a thickness of 6 μm was formed thereon. When the calorific value of this conductive adhesive layer (c) was measured from 25 ° C. to 200 ° C. at a heating rate of 10 ° C./min using DSC, the calorific value was 180 J / g.

When the storage elastic modulus of this conductive adhesive layer (c) was measured at a rate of temperature increase of 10 ° C./min and a frequency of 1 Hz using a viscoelasticity measuring device, the storage elastic modulus at 40 ° C. was 0.05 GPa. there were.

  The insulating adhesive layer (a) and conductive adhesive layer (c) obtained above were laminated with a roll laminator while heating at 50 ° C. to obtain a laminated film. Subsequently, after peeling off the PET film on the conductive adhesive layer (c) on the conductive adhesive layer (c) side of the obtained laminated film, the insulating adhesive layer (b) obtained above is applied. Laminating with a roll laminator while heating at 50 ° C., the thickness of the insulating adhesive layer (a) is 15 μm, the thickness of the conductive adhesive layer (c) is 6 μm, and the thickness of the insulating adhesive layer (b) Obtained an adhesive film for circuit connection having a 3-layer structure of 2 μm.

(Comparative Example 4)
Comparative Example 3 except that the thickness of the insulating adhesive layer (a) was 18 μm, the thickness of the insulating adhesive layer (b) was 2 μm, and the thickness of the conductive adhesive layer (c) was 3 μm. Through this process, an adhesive film for circuit connection having a three-layer structure was obtained.

[Measurement of the number of trapped particles]
Using the adhesive film for circuit connection prepared in the above examples and comparative examples, a chip (1.2 mm) with gold bumps (area: 30 μm × 50 μm, space between bumps: 12 μm, bump height: 15 μm, number of bumps: 300) × 19 mm, thickness: 500 μm) and a glass substrate with an ITO circuit (circuit thickness: 0.15 μm, glass substrate thickness: 0.5 mm) were connected as shown below.

First, an adhesive film for circuit connection (1.5 mm × 20 mm) was attached to a glass substrate with an ITO circuit by heating and pressing for 2 seconds under the conditions of 80 ° C. and 0.98 MPa (10 kgf / cm ² ). At this time, in the adhesive film for circuit connection having a three-layer structure, the insulating adhesive layer (b) was attached to the glass substrate after the PET film on the insulating adhesive layer (b) was peeled off.

  Next, the PET film on the insulating adhesive layer (a) of the adhesive film for circuit connection was peeled off, and after aligning the bumps of the chip and the glass substrate with ITO circuit, 190 ° C., 40 g / bump, 10 The insulating adhesive layer (a) was affixed to the chip by heating and pressing from above the chip for 2 seconds, and the chip and the glass substrate were connected through the adhesive film for circuit connection.

  At this time, the number of conductive particles captured by the gold bumps was measured at a magnification of 200 to 500 times using a microscope (trade name: ECLIPSE L200, manufactured by Nikon Corporation). Thereby, the minimum value of the particle | grain capture | acquisition number of a gold bump was calculated | required about each of the adhesive film for circuit connection produced by the said Example and comparative example. The results are shown in Table 1.

[Measurement of insulation resistance]
Using the adhesive films for circuit connection produced in the above-mentioned examples and comparative examples, a chip (1.9 mm ×× with gold bumps (area: 30 μm × 100 μm, space between bumps: 10 μm, height: 15 μm, number of bumps: 472)) 15 mm, thickness: 500 μm) and a glass substrate with an ITO circuit (circuit thickness: 0.15 μm, glass substrate thickness: 0.5 mm) were connected as shown below.

First, an adhesive film for circuit connection (2.0 mm × 20 mm) was applied to a glass substrate with an ITO circuit by heating and pressing for 2 seconds under the conditions of 80 ° C. and 0.98 MPa (10 kgf / cm ² ). At this time, in the adhesive film for circuit connection having a three-layer structure, the insulating adhesive layer (b) was attached to the glass substrate after the PET film on the insulating adhesive layer (b) was peeled off.

  Next, the PET film on the insulating adhesive layer (a) of the adhesive film for circuit connection was peeled off, and after aligning the bumps of the chip and the glass substrate with ITO circuit, 190 ° C., 40 g / bump, 10 The insulating adhesive layer (a) was affixed to the chip by heating and pressing from above the chip for 2 seconds, and the chip and the glass substrate were connected through the adhesive film for circuit connection.

  The connection sample thus obtained was subjected to the following current and moisture resistance test. That is, the process which applied DC15V for 500 hours in the environment of 85 degreeC and 85% RH was performed with respect to the connection sample.

About the insulation resistance value of the connection sample after the energization and moisture resistance test, an insulation resistance meter (trade name: R8340A, manufactured by Advantest Co., Ltd.) was used to measure the insulation resistance between adjacent bumps at room temperature at a voltage of 50V. Measurement was performed under the condition of an application time of 60 seconds. Thereby, it was judged whether the insulation characteristic between adjacent bumps was good. In this case, an insulation resistance value of 1 × 10 ⁸ Ω or more is a good insulation characteristic, an insulation resistance value between all adjacent bumps of 1 × 10 ⁸ Ω or more is A, and an insulation resistance value is 1 × 10 ^8. An evaluation including B between adjacent bumps of less than Ω was evaluated as B. The results are shown in Table 1.

[Measurement of connection resistance]
Using the adhesive films for circuit connection prepared in the above examples and comparative examples, a chip (1.2) with gold bumps (area: 30 μm × 50 μm, space between bumps: 12 μm, bump height: 15 μm, number of bumps: 300) × 19 mm, thickness: 500 μm) and a glass substrate with an ITO circuit (circuit thickness: 0.15 μm, glass substrate thickness: 0.5 mm) were connected as shown below.

First, an adhesive film for circuit connection (1.5 mm × 20 mm) was applied to a glass substrate with an ITO circuit by heating and pressing for 2 seconds under the conditions of 80 ° C. and 0.98 MPa (10 kgf / cm ² ). At this time, in the adhesive film for circuit connection having a three-layer structure, the insulating adhesive layer (b) was attached to the glass substrate after the PET film on the insulating adhesive layer (b) was peeled off.

  Next, the PET film on the insulating adhesive layer (a) of the adhesive film for circuit connection was peeled off, and after aligning the bumps of the chip and the glass substrate with ITO circuit, 190 ° C., 40 g / bump, 10 The insulating adhesive layer (a) was affixed to the chip by heating and pressurizing from the top of the chip under the conditions for seconds, and the main connection between the chip and the glass substrate through the adhesive film for circuit connection was performed.

  The connection samples thus obtained were subjected to the following moisture resistance test. That is, the connection sample was left to stand for 1000 hours in an environment of 85 ° C. and 85% RH.

  About the connection resistance value of the connection sample after a moisture-proof test, the connection resistance for every bump was measured by the 4-terminal method using the digital multimeter (Corporation | KK ADVANTEST Co., Ltd. make, brand name: R6451A). Thereby, it was judged whether conduction was good. In this case, a connection resistance value of 20Ω or less was evaluated as good continuity, all bumps having connection resistance values of 20Ω or less were evaluated as A, and those including bumps having connection resistance values exceeding 20Ω were evaluated as B. The results are shown in Table 1. “Open” in Table 1 indicates that the connection resistance value could not be measured.

  As shown in Table 1, the thickness of the conductive adhesive layer is 2 times or less the average particle diameter of the conductive particles, and the storage elastic modulus at 40 ° C. of the conductive adhesive layer is 0.1 to 1. In the adhesive films for circuit connection of Examples 1 to 4 that are 5 GPa, the number of particles captured on the electrodes is sufficient, and both the insulation resistance value after the energization moisture resistance test and the connection resistance value after the moisture resistance test are good. Was confirmed.

  On the other hand, in the adhesive films for circuit connection of Comparative Example 1 and Comparative Example 2 in which the thickness of the conductive adhesive layer is larger than twice the average particle diameter of the conductive particles, the insulation resistance value after the energization and moisture resistance test and the connection after the moisture resistance test It was confirmed that the resistance value was inferior. Furthermore, in the adhesive films for circuit connection of Comparative Example 3 and Comparative Example 4 in which the storage elastic modulus at 40 ° C. of the conductive adhesive layer is less than 0.1 GPa, the connection resistance value and the number of particles trapped after the moisture resistance test are inferior. It was confirmed.

  From the above results, according to the adhesive film for circuit connection according to the present invention, it is possible to reliably capture a sufficient number of conductive particles between the facing circuit electrodes, thereby enabling high resolution and long-term use. It was confirmed that the connection reliability was excellent.

It is a schematic cross section which shows suitable one Embodiment of the adhesive film for circuit connection which concerns on this invention. 1 is a schematic cross-sectional view showing a preferred embodiment of a circuit member connection structure according to the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Conductive particle, 2 ... Adhesive, 3 ... Conductive adhesive layer, 2a-5a ... Hardened | cured material, 4 ... 1st insulating adhesive layer, 5 ... 2nd insulating adhesive layer, 10 ... 1st One circuit member, 11 ... first substrate, 12 ... first circuit electrode, 20 ... second circuit member, 21 ... second substrate, 22 ... second circuit electrode, 100 ... adhesive film for circuit connection , 100a: circuit connection member, 200: connection structure of circuit members, h1: height of the first circuit electrode, h2: height of the second circuit electrode.

Claims (7)

A first circuit member having a first circuit electrode formed on the main surface of the first substrate; and a second circuit member having a second circuit electrode formed on the main surface of the second substrate. An adhesive film for circuit connection for connecting the first circuit electrode and the second circuit electrode in a state of being opposed to each other,
A conductive adhesive layer containing conductive particles and an adhesive;
An insulating first insulating adhesive layer formed on one side of the conductive adhesive layer;
An insulating second insulating adhesive layer formed on a surface opposite to the surface on which the first insulating adhesive layer of the conductive adhesive layer is formed, and
A circuit in which the thickness of the conductive adhesive layer is not more than twice the average particle size of the conductive particles, and the storage elastic modulus at 40 ° C. of the conductive adhesive layer is 0.1 to 1.5 GPa. Adhesive film for connection. The adhesive contains a curable resin that is cured by heat or light,
The conductive adhesive layer further comprises a film-forming polymer;
Each of the first insulating adhesive layer and the second insulating adhesive layer has a storage elastic modulus at 40 ° C. of less than 0.1 GPa,
The adhesive film for circuit connection according to claim 1, wherein the thickness of at least one of the first insulating adhesive layer and the second insulating adhesive layer is 0.1 to 5.0 μm.   The conductive adhesive layer gives a calorific value of 25 to 130 J / g in differential scanning calorimetry, and gives a curing reaction rate of 20 to 100% based on the calorific value. Or the adhesive film for circuit connection of 2. A first circulating member in which a first circuit electrode is formed on the main surface of the first substrate;
A second circuit member having a second circuit electrode formed on the main surface of the second substrate;
A circuit connection member that is disposed between the first circuit member and the second circuit member, and is made of a cured product of the adhesive film for circuit connection according to any one of claims 1 to 3,
A circuit member connection structure in which the first circuit electrode and the second circuit electrode are electrically connected by the circuit connection member in a state of being opposed to each other. The height of at least one of the first circuit electrode and the second circuit electrode is 3.0 μm or less,
The thickness of at least one of the first insulating adhesive layer and the second insulating adhesive layer is 0.1 to 5.0 μm,
5. The insulating adhesive layer according to claim 4, wherein the thickness of the layer is 0.1 to 5.0 μm on the circuit electrode side where the height of the circuit electrode is 3.0 μm or less. Circuit member connection structure. A first circuit member having a first circuit electrode formed on a main surface of the first substrate;
A second circuit member having a second circuit electrode formed on the main surface of the second substrate;
The adhesive film for circuit connection according to any one of claims 1 to 3, wherein the adhesive film for circuit connection is disposed between the first circuit member and the second circuit member, and the first circuit electrode and the second circuit member. A method for connecting circuit members, wherein the first circuit electrode and the second circuit electrode are electrically connected by heating and pressurizing the circuit electrode so as to face each other. The circuit electrode height of at least one of the first circuit electrode and the second circuit electrode is 3.0 μm or less,
The thickness of at least one of the first insulating adhesive layer and the second insulating adhesive layer is 0.1 to 5.0 μm,
By placing the insulating adhesive layer having a thickness of 0.1 to 5.0 μm on the circuit electrode side where the height of the circuit electrode is 3.0 μm or less, and heating and pressing, The circuit member connection according to claim 6, wherein the first circuit member and the second circuit member are connected such that the first circuit electrode and the second circuit electrode are electrically connected. Method.

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