JP2010009804A - Anisotropic conductive adhesive sheet and fine connection structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anisotropic conductive adhesive sheet with low connection resistance, high insulation reliability, and superior fine circuit connectivity. <P>SOLUTION: The anisotropic conductive adhesive sheet is comprised by including a first layer comprising a first resin composition including at least conductive particles, insulation particles, and insulation resin, and a second layer comprising a second resin composition including at least a hardener and curable insulation resin. It is characterized by that the first layer exists in an area within 1.5 times of a mean particle diameter of the conductive particles along a thickness direction from a one side surface, a thickness of a thinnest portion of the first layer is smaller than the mean particle diameter of the conductive particles, and a melt viscosity at 180°C of the first resin composition is higher than a melt viscosity at 180°C of the second resin composition. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an anisotropic conductive adhesive sheet and a fine connection structure excellent in fine circuit connectivity and excellent in insulating properties in fine pitch connection.

  So far, with regard to anisotropic conductive adhesive sheets for connecting microcircuits, various conductive particles and anisotropic conductive adhesive configurations have been studied in order to improve connectivity and prevent short circuits. . For example, a method of blending insulating particles having a thermal expansion coefficient equivalent to that of the conductive particles (see Patent Document 1), and a method of attaching the insulating particles to the surface of the conductive particles to prevent a short circuit (see Patent Document 2) Alternatively, a method of covering the surface of conductive particles with an electrically insulating resin (see Patent Document 3), a method of stacking a layer containing conductive particles and a layer not containing conductive particles, and preventing a short circuit between adjacent circuits (patent References 4 and 5), the terminal circuit is covered with a photosensitive resin, the part other than the connection part is selectively cured to eliminate the adhesiveness, the conductive particles are attached to the adhesive part, and then the adhesive resin is used. A method of covering and preventing a short circuit between adjacent terminal circuits (see Patent Document 6) is well known. Further, a method is known in which conductive particles are arranged in a single layer to reduce the number of conductive particles in the anisotropic conductive adhesive sheet and to achieve a balance between connection and insulation (Patent Documents 7 and 8).

  However, in the prior art such as blending insulating particles, it is necessary to prevent the short circuit due to the aggregation of the conductive particles in the inter-terminal direction and to ensure insulation, so it is necessary to blend many insulating particles. . On the other hand, at the time of crimping, in order to ensure connectivity, in the connection part, it is necessary to exclude insulating particles while maintaining the number of conductive particles. In the case of circuit connection, it was not possible to satisfy both the insulation and the number of connected particles. Further, even in the prior art such as short circuit prevention by the adhesive configuration, in the case of the fine circuit connection, insulation and electrical connectivity cannot be satisfied at the same time.

JP-A-6-349339 Japanese Patent No. 28958872 Japanese Patent Publication No. 7-99644 JP-A-6-45024 JP 2003-49152 A Japanese Patent No. 3165477 JP 2006-335910 A International Publication No. 2007/125993 Pamphlet

  The present invention relates to an anisotropic conductive adhesive sheet that realizes good electrical insulation between adjacent circuits without impairing good electrical connectivity in the fine circuit, its manufacturing method, and fine connection using the same An object is to provide a structure.

  As a result of intensive studies to solve the above problems, the present inventors have found that the conductive particles are present in a certain range without contacting with a certain proportion or more of the conductive particles. Insulating particles are present in a certain existence region with respect to the existence region in the thickness direction of the conductive particles, and the fluidity of the existence region is in a certain range. It was found that the above problems can be solved by using the anisotropic conductive adhesive sheet.

  That is, one aspect of the present invention is a second layer including at least a first layer composed of a first resin composition containing conductive particles, insulating particles, and an insulating resin, and at least a curing agent and a curable insulating resin. An anisotropic conductive adhesive sheet comprising a second layer made of a resin composition, wherein the first layer made of the first resin composition has conductive particles along the thickness direction from one surface. The thickness of the thinnest part of the first layer is smaller than the average particle diameter of the conductive particles, and is 180 ° C. of the first resin composition. The anisotropic conductive adhesive sheet is characterized in that the melt viscosity at is higher than the melt viscosity at 180 ° C. of the second resin composition.

In the anisotropic conductive adhesive sheet, the melt viscosity at 180 ° C. of the first resin composition is in the range of 1,500 Pa · s to 20,000 Pa · s, and the second resin composition at 180 ° C. It is preferably in the range of 30 to 150 times the melt viscosity. Moreover, the average particle diameter of the conductive particles is 1 to 8 μm, the average particle interval between adjacent conductive particles is 20 μm or less, and the thickness of the anisotropic conductive adhesive sheet is 1. It is preferably 5 times or more and 40 μm or less. Further, the average particle size of the insulating particles is 0.1 to 0.7 times the average particle size of the conductive particles, and 50% or more of the number of insulating particles exists without being in contact with other insulating particles. Preferably it is.
The number of insulating particles is preferably in the range of 2 to 200 times the number of conductive particles.

In the second aspect of the present invention, an adhesive layer is provided on a biaxially stretchable film to form a laminate, and conductive particles having an average particle diameter of 2 to 8 μm are adhered on the laminate, thereby forming a conductive particle-adhered film. An insulating particle layer containing at least insulating particles and an insulating resin is formed on the conductive particles of the conductive particle adhesion film, and the average particle interval between the conductive particles is the average particle size of the conductive particles. After biaxially stretching and holding so as to be 0.5 times or more and 5 times or less, at least a curing agent and a stretching containing the conductive particles and the insulating particles on an adhesive sheet containing a curable insulating resin It is the manufacturing method of one anisotropic conductive adhesive sheet of this invention characterized by including the process of transferring a sheet | seat and producing an adhesive sheet.
In the method for producing the anisotropic conductive adhesive sheet, it is preferable that the biaxially stretchable film is a long film and the adhesive sheet is a long adhesive sheet.
According to a third aspect of the present invention, there is provided a method for connecting circuit terminals, wherein an electronic circuit component and a circuit board are connected by the anisotropic conductive adhesive sheet of the present invention.
A fourth aspect of the present invention is a circuit terminal connection structure in which an electronic circuit component and a circuit board are connected by the anisotropic conductive adhesive sheet of the present invention.
According to a fifth aspect of the present invention, there is provided a finely connected structure including an electronic circuit component and a circuit board connected by the anisotropic conductive adhesive sheet of the present invention.

  The anisotropic conductive adhesive sheet and fine connection structure of the present invention have good electrical connectivity between connected connection terminals, and have good insulating properties between adjacent connection terminals. That is, the conductive particles are arranged at specific intervals in the in-plane direction of the anisotropic conductive adhesive sheet that requires insulation, the insulating particles are arranged within the intervals, and the fluidity at the time of connection is controlled. Thus, by making the insulating particles function effectively, it is possible to ensure good insulation between adjacent connection terminals while maintaining good connectivity.

Hereinafter, the present invention will be specifically described. First, the conductive particles will be described.
As the conductive particles, it is preferable to use at least one selected from resin particles coated with noble metal, metal particles coated with noble metal, metal particles, alloy particles coated with noble metal, and alloy particles.
As the resin particles coated with the noble metal, it is preferable to use those obtained by coating spherical particles such as polystyrene, benzoguanamine, and polymethyl methacrylate with nickel and gold in this order.

Resin particles coated with a noble metal can be formed using softer resin particles according to the hardness of the fine connection terminal (bump) to be connected.
When the bump hardness to be connected is less than 50 Hv in terms of Vickers hardness, it is preferable to use flexible resin particles such as polymethacrylate resin. Moreover, when bump hardness is 50 Hv or more, it is preferable to use hard resin particles, such as a benzoguanamine resin.

  As the metal particles coated with the noble metal, it is preferable to use a metal particle such as nickel or copper coated with a noble metal such as gold, palladium or rhodium on the outermost layer. As a coating method, a thin film forming method such as a vapor deposition method or a sputtering method, a coating method using a dry blend method, a wet method such as an electroless plating method or an electrolytic plating method can be used. From the viewpoint of mass productivity, the electroless plating method is preferable.

  As the metal particles, those selected from metals such as silver, copper and nickel are preferably used. The alloy particles preferably have a melting point of 150 ° C. or more and 500 ° C. or less, and more preferably low melting point alloy particles having a melting point of 150 ° C. or more and 350 ° C. or less. When the melting point is 500 ° C. or less, a metal bond can be formed between the connection terminals, which is preferable from the viewpoint of connection reliability. Moreover, it is preferable that melting | fusing point is 150 degreeC or more from a viewpoint of heat-resistant connection reliability.

As the alloy particles coated with the noble metal, for example, alloy particles composed of two or more kinds selected from gold, silver, copper, nickel, tin, zinc, bismuth, indium, etc. are coated with the noble metal using the above method or the like. Can be used.
As the alloy particles, for example, alloy particles composed of two or more selected from gold, silver, copper, nickel, tin, zinc, bismuth, indium and the like are preferable. When alloy particles having a melting point of 150 ° C. or higher and 500 ° C. or lower are used, it is preferable to coat the particle surface with a flux or the like in advance. It is preferable to use a so-called flux because the surface oxides can be removed. As the flux, fatty acids such as abietic acid can be used.

  The ratio of the average particle size to the maximum particle size of the conductive particles is preferably 2 or less, and more preferably 1.5 or less. The particle size distribution of the conductive particles is preferably narrower, and the geometric standard deviation of the particle size distribution of the conductive particles is preferably 1.2 to 2.5, and preferably 1.2 to 1.4. Is particularly preferred. When the geometric standard deviation is the above value, the variation in particle size is reduced. Usually, when a certain gap exists between two terminals to be connected, it is considered that the conductive particles function more effectively as the particle diameters become uniform.

  The geometric standard deviation of the particle size distribution is a value obtained by dividing the σ value of the particle size distribution (particle size value of 84.13% cumulative) by the particle size value of 50% cumulative. When the particle size distribution (logarithm) is set on the horizontal axis of the particle size distribution graph and the cumulative value (%, cumulative number ratio, logarithm) is set on the vertical axis, the particle size distribution is almost linear, and the particle size distribution is lognormal distribution. Follow. The cumulative value indicates the number ratio of particles having a certain particle size or less with respect to the total number of particles, and is expressed in%. The sharpness of the particle size distribution is expressed by the ratio of σ (the cumulative particle size value of 84.13%) and the average particle size (the cumulative particle size value of 50%). The σ value is an actual measurement value or a read value from the plot value of the graph.

The average particle size and particle size distribution can be measured using a known method and apparatus, and a wet particle size distribution meter, a laser particle size distribution meter, or the like can be used. Alternatively, the average particle size and particle size distribution may be calculated by observing the particles with an electron microscope or the like. The average particle size and particle size distribution of the present invention can be determined by a laser particle size distribution meter.
The average particle size of the conductive particles is preferably 2 to 8 μm, more preferably 2 to 6 μm, and still more preferably 3 to 5 μm. The thickness is preferably 8 μm or less from the viewpoint of insulation, is less susceptible to variations in height of connection terminals and the like, and is preferably 2 μm or more from the viewpoint of electrical connectivity.

  Any insulating particles can be used as long as sufficient insulating properties are possible. For example, thermoplastic resin particles such as acrylic resin, styrene resin, acrylic-styrene copolymer resin, resin particles such as benzoguanamine resin and phenol resin, thermosetting resin particles such as solid epoxy resin, silicon oxide, titanium oxide, etc. Ceramic particles or the like can be used. A thermoplastic resin is preferred because it is easy to ensure the connectivity during crimping. From the viewpoint of securing connectivity during pressure connection, the resin preferably has a glass transition temperature of 25 ° C. or higher and 150 ° C. or lower, more preferably 50 ° C. or higher and 130 ° C. or lower, and even more preferably 80 ° C. or higher and 120 ° C. or lower. As the shape, spherical particles are preferable. As a method for measuring the glass transition temperature, a known method can be used. Specifically, it can be measured using a TMA-50 thermomechanical analyzer (manufactured by Shimadzu Corporation) at a temperature rising rate of 10 ° C./min.

  The average particle size of the insulating particles is smaller than the average particle size of the conductive particles and smaller than the conductive particle interval, but may be 0.1 to 0.7 times the average particle size of the conductive particles. Preferably, it is 0.15 times or more and 0.6 times or less, and more preferably 0.2 times or more and 0.5 times or less. It is preferably 0.1 times or more from the viewpoint of insulation, and is preferably smaller than the average particle diameter of the conductive particles from the viewpoint of connectivity. The number of insulating particles is preferably in the range of 2 to 200 times the number of conductive particles, more preferably in the range of 3 to 100 times, and still more preferably in the range of 5 to 100 times. It is preferably 2 times or more from the viewpoint of ensuring insulation, and 200 times or less is preferable from the viewpoint of adhesion.

Next, the anisotropic conductive adhesive sheet will be described.
The anisotropic conductive adhesive sheet of the present invention is in a region within 1.5 times, more preferably within 1.2 times the average particle diameter of the conductive particles along the thickness direction from one surface of the conductive adhesive sheet. There is a first layer.

  The thickness of the thinnest part of the first layer is smaller than the average particle diameter of the conductive particles, preferably smaller than 0.7 times the average particle diameter of the conductive particles, more preferably the average particle diameter of the conductive particles. Less than 0.5 times. From the viewpoint of connectivity, the insulating particles present on the connection surface of the conductive particles are preferably 10% or less of the total number, more preferably 5% or less, and still more preferably 1% or less. The fluidity of the first resin composition in the present invention is lower than the fluidity of the second resin composition.

The region where the insulating particles are present can be measured by observing the cross section of the anisotropic conductive adhesive sheet with a microscope. In order to confirm more accurately, it is preferable to observe 10 cross-sections using an electron microscope or a laser microscope, and use the average value.
When a layer containing insulating particles and conductive particles is formed in advance and laminated with an adhesive layer not containing conductive particles and insulating particles, a layer containing insulating particles and conductive particles is applied from the surface to the laser. The region where the insulating particles and the conductive particles exist can be measured by observing with a microscope.

The first resin composition is a composition including at least an insulating resin, insulating particles, and conductive particles, but may include a curing agent. The melt viscosity at 180 ° C. of the first resin composition means that when the first resin composition contains insulating particles, conductive particles, and a curing agent, the insulating particles, conductive particles, and the curing agent are excluded. Represents the melt viscosity of the resin composition 1 at 180 ° C., preferably from 1,500 Pa · s to 20,000 Pa · s, more preferably from 1,800 Pa · s to 15,000 Pa · s, More preferably, it is in the range of 000 Pa · s to 10,000 Pa · s.
The melt viscosity of the first resin composition 1 is preferably 1,500 Pa · s or more from the viewpoint that it is difficult for the insulating particles to move during connection, and is 20,000 Pa · s or less from the viewpoint of connectivity. Is preferred.

  The second resin composition is composed of a composition containing at least a curing agent and a curable insulating resin. The melt viscosity at 180 ° C. of the second resin composition is the second resin composition. Represents the melt viscosity at 180 ° C. of the composition excluding the curing agent, and when the insulating resin, conductive particles, and the curing agent are included from the first resin composition, the resin composition excluding the curing agent (first The melt viscosity at 180 ° C. of one resin composition 1) is preferably in the range of 30 to 150 times the melt viscosity at 180 ° C. of the composition excluding the curing agent from the second resin composition. More preferably, it is 40 times to 120 times, and still more preferably 50 times to 100 times. It is preferably 30 times or more from the viewpoint that the movement of the insulating particles hardly occurs at the time of connection, and preferably 150 times or less from the viewpoint of connectivity. The melt viscosity can be measured using an E-type viscometer.

In the anisotropic conductive adhesive sheet, the average particle interval between adjacent conductive particles is preferably 20 μm or less. The average particle spacing between adjacent conductive particles is more preferably 0.5 to 5 times the average particle size of the conductive particles, and more preferably 1.5 to 3 times the average particle size. It is as follows. From the viewpoint of preventing particle aggregation due to particle flow at the time of connection and ensuring insulation, it is preferably 0.5 times or more of the average particle diameter, and from the viewpoint of fine connection, it is 5 times or less and 20 μm or less of the average particle diameter Preferably there is.
The “adjacent conductive particles” in the present invention are defined as follows.
That is, arbitrary conductive particles are selected, and the six conductive particles closest to the conductive particles are referred to. In this case, the average particle interval between the adjacent conductive particles is obtained as follows.

First, a photograph of the anisotropic conductive adhesive sheet is taken with an optical microscope from the surface side where the conductive particles are present. Next, arbitrary 20 conductive particles are selected, the distance from the 6 conductive particles closest to the respective conductive particles is measured, the average value of the whole is obtained, and the average particle interval is obtained. . Regarding the number of insulating particles, a photograph enlarged with an optical microscope or the like is taken from the surface side where the insulating particles are present, and the number of insulating particles is measured from the photograph.
It is preferable that 50% or more of the number of insulating particles exist without contact with other insulating particles, more preferably 70% or more, more preferably 90% or more exist without contact with other insulating particles. It is preferable. From the viewpoint of adhesion to the substrate and the viewpoint of electrical connectivity, 50% or more is preferably present without contacting with other insulating particles.

The number of insulating particles is preferably 2 to 200 times the number of conductive particles, and more preferably 3 to 150 times. More preferably, it is 5 to 100 times. It is preferably 2 times or more from the viewpoint of insulation, and preferably 200 times or less from the viewpoint of connectivity and adhesion to the substrate. The thickness of the anisotropic conductive adhesive sheet is preferably 1.5 times or more and 40 μm or less, more preferably 2 times or more and 20 μm or less of the above average particle interval. From the viewpoint of mechanical connection strength, the average particle spacing is preferably 1.5 times or more, and from the viewpoint of preventing reduction in the number of connected particles due to particle flow during connection, it is preferably 40 μm or less.

  In the present invention, “the conductive particles are present without being in contact with other conductive particles” means that the conductive particles are present independently without being aggregated. Hereinafter, the expressions “exist alone” and “single particle” may be used in this sense. In the present invention, 90% or more of the conductive particles are present without being in contact with other conductive particles, but 95% or more are present without being in contact with other conductive particles. preferable.

  The blending amount of the conductive particles in the anisotropic conductive adhesive sheet is preferably 0.5 parts by mass to 20 parts by mass with respect to 100 parts by mass of the components including the curing agent and the curable insulating resin. It is particularly preferable that the amount is 1 to 10 parts by mass. 20 parts by mass or less is preferable from the viewpoint of insulation, and 0.5 parts by mass or more is preferable from the viewpoint of electrical connectivity.

The conductive particles may be partially exposed from the one side surface of the anisotropic conductive adhesive sheet. From the viewpoint of adhesiveness, it is preferable that the insulating particles are not exposed.
In the anisotropic conductive adhesive sheet, the position where the conductive particles are present with respect to the thickness direction of the anisotropic conductive adhesive sheet can be measured by a laser microscope capable of measuring the displacement in the focal direction. At the same time, it is also possible to measure the number of conductive particles that exist without contacting other conductive particles. When the displacement in the focal direction is measured using the laser microscope, the displacement measurement resolution is preferably 0.1 μm or less, and particularly preferably 0.001 μm or less.

  As the curable insulating resin used for the anisotropic conductive adhesive sheet, a thermosetting resin, a photocurable resin, light and thermosetting resin, an electron beam curable resin, or the like can be used. In view of ease of handling, it is preferable to use a thermosetting insulating resin. As the thermosetting resin, an epoxy resin, an acrylic resin, or the like can be used, and an epoxy resin is particularly preferable.

  The epoxy resin is a compound having two or more epoxy groups in one molecule, and is preferably a compound having a glycidyl ether group, a glycidyl ester group or an alicyclic epoxy group, or a compound obtained by epoxidizing a double bond in the molecule. . Specifically, bisphenol A type epoxy resin, bisphenol F type epoxy resin, naphthalene type epoxy resin, novolac phenol type epoxy resin, or modified epoxy resins thereof can be used. The content of the insulating resin is preferably 5% by mass or more and 80% by mass or less, more preferably 10% by mass or more and 70% by mass or less, and further preferably 20% by mass or more and 50% by mass or less. . From the viewpoint of adhesion reliability, it is preferably 5% or more, and from the viewpoint of connection reliability, it is preferably 90% by mass or less.

  As a hardening | curing agent used for an anisotropically conductive adhesive sheet, what is necessary is just to be able to harden the said curable insulating resin. When a thermosetting resin is used as the curable insulating resin, a resin that can be cured by reacting with the thermosetting resin at 100 ° C. or higher is preferable. In the case of an epoxy resin, a latent curing agent is preferable from the viewpoint of storage stability. For example, an imidazole curing agent, a capsule type imidazole curing agent, a cationic curing agent, a radical curing agent, a Lewis acid curing agent. An agent, an amine imide curing agent, a polyamine salt curing agent, a hydrazide curing agent, and the like can be used. From the viewpoint of storage stability and low-temperature reactivity, capsule-type imidazole curing agents are preferred. The content of the curing agent is preferably 5% by mass to 90% by mass, more preferably 10% by mass to 70% by mass, and still more preferably 20% by mass to 50% by mass. From the viewpoint of adhesion reliability, it is preferably 5% by mass or more, and from the viewpoint of storage stability, it is preferably 90% by mass or less.

  In addition to the curing agent and the curable insulating resin, a thermoplastic resin or the like may be blended in the anisotropic conductive adhesive sheet. By blending a thermoplastic resin, it can be easily formed into a sheet. In this case, the blending amount is preferably 200 parts by mass or less, particularly preferably 100 parts by mass or less, based on 100 parts by mass of the components including the curing agent and the curable insulating resin.

  Thermoplastic resins that can be blended with the curable insulating resin of the present invention include phenoxy resin, polyvinyl acetal resin, polyvinyl butyral resin, alkylated cellulose resin, polyester resin, acrylic resin, styrene resin, urethane resin, polyethylene terephthalate resin, etc. There may be a combination of one or more resins selected from them. Among these resins, a resin having a polar group such as a hydroxyl group or a carboxyl group is preferable from the viewpoint of adhesive strength. Moreover, it is preferable that a thermoplastic resin contains 1 or more types of thermoplastic resins whose glass transition temperature is 80 degreeC or more.

In the anisotropic conductive adhesive sheet of the present invention, an additive may be blended with the above components. In order to improve the adhesion between the anisotropic conductive adhesive sheet and the adherend, a coupling agent can be blended as an additive. As the coupling agent, a silane coupling agent, a titanium coupling agent, an aluminum coupling agent, or the like can be used, and a silane coupling agent is preferable. Examples of the silane coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-mercaptotrimethoxysilane, γ-aminopropyltrimethoxysilane, β-aminoethyl-γ- Aminopropyltrimethoxysilane, γ-ureidopropyltrimethoxysilane, and the like can be used.
The blending amount of the coupling agent is preferably 0.01 parts by mass to 1 part by mass with respect to 100 parts by mass of the components including the curing agent and the curable insulating resin. 0.01 mass part or more is preferable from a viewpoint of adhesive improvement, and 1 mass part or less is preferable from a reliability viewpoint.

  Furthermore, an ion scavenger can be blended as an additive in order to prevent a decrease in insulation due to an ionic component in the anisotropic conductive adhesive sheet during moisture absorption. As the ion scavenger, an organic ion exchanger, an inorganic ion exchanger, an inorganic ion adsorbent, and the like can be used, but an inorganic ion exchanger excellent in heat resistance is preferable.

  As the inorganic ion exchanger, zirconium compounds, zirconium bismuth compounds, antimony bismuth compounds, and magnesium aluminum compounds can be used. There are positive ion type, negative ion type, and both ion types as ion types to be exchanged, but metal ions (positive ions) that cause direct ion migration, increase electrical conductivity, and cause generation of metal ions. Both anions are preferred because both anions can be exchanged.

The average particle size of the ion scavenger to be blended is preferably 0.01 μm or more and 5 μm or less, and more preferably 0.01 μm or more and 1 μm or less.
The compounding amount of the ion scavenger is preferably 0.01 to 3 parts by mass with respect to 100 parts by mass of the resin component. When the blending amount is less than 0.01 parts by mass, the ion trapping effect is insufficient, and 3 parts by mass or less is preferable from the viewpoint of electrical connection.

Next, the manufacturing method of an anisotropically conductive adhesive sheet is demonstrated.
As a method for producing an anisotropic conductive adhesive sheet, conductive particles dispersed and arranged in advance are laminated on an insulating layer in which insulating particles are dispersed and thinner than the average particle diameter, and an adhesive layer containing at least a curable resin and a curing agent. It is preferable to do.

  As a method for producing an anisotropic conductive adhesive sheet, an adhesive layer is formed on a biaxially stretchable film or sheet, conductive particles are arranged in a single layer thereon, and at least insulating particles and insulation are formed thereon. Forming a layer made of a conductive resin, stretching them so that the thickness of the thinnest part of the first layer is smaller than the average particle diameter of the conductive particles, dispersing and arranging the conductive particles, and stretching A method of transferring the adhesive sheet to an adhesive sheet made of at least a curing agent and a curable insulating resin in a state where the above state is maintained is preferable.

  Further, an adhesive layer is formed on a biaxially stretchable film or sheet, conductive particles are arranged in a single layer thereon, and they are stretched and fixed so that the conductive particles are dispersed and arranged. An adhesive sheet made of at least a curing agent and a curable insulating resin is transferred onto the insulating sheet by transferring conductive particles, which are prepared by laminating an insulating layer made of at least insulating particles and an insulating resin, and dispersed and arranged on the insulating sheet. It is possible to use a method of transferring the toner.

  As a biaxially stretchable film, a known resin film or the like can be used. Specifically, polyethylene resins, polypropylene resins, polyester resins, polyvinyl butyral resins, polyvinyl alcohol resins, polyvinylidene chloride resins and the like alone or copolymers, or rubber sheets such as nitrile rubber, butadiene rubber, silicone rubber, etc. It is preferable to use a flexible and stretchable resin film. Polypropylene resin and polyester resin are particularly preferable. The shrinkage after stretching is preferably 10% or less.

  As a method for dispersing and fixing conductive particles on a biaxially stretchable film, a known method can be used. For example, a method in which a pressure-sensitive adhesive layer containing at least a thermoplastic resin is formed on the biaxially stretchable film, and conductive particles are brought into contact with and adhered to the film, and placed in a single layer by applying a load with a rubber roll or the like. Can be taken. In this case, a method of repeating the adhesion-roll operation several times is preferable for filling without gaps. In the case of spherical conductive particles, since the closest packing is the most stable structure, it can be filled relatively easily. Alternatively, a method of applying a pressure-sensitive adhesive on the biaxially stretchable film to form an adhesive layer, attaching conductive particles thereon, repeating the attachment several times if necessary, and dispersing and arranging in a single layer, etc. Can be used.

  As a method for stretching a biaxially stretchable film in which conductive particles are arranged in a single layer, a known method can be used, but a biaxial stretching device is preferably used from the viewpoint of uniform dispersion alignment. From the viewpoint of particle spacing, the degree of stretching is preferably 50% or more and 400% or less, and more preferably 100% or more and 300% or less. In addition, 100% stretching means that the length of the portion stretched along the stretching direction is 100% of the length before stretching. The stretching direction is arbitrary, but biaxial stretching with a stretching angle of 90 ° is preferable, and simultaneous stretching is preferable. In the case of biaxial stretching, the degree of stretching in each direction may be the same or different.

As the biaxial stretching apparatus, a simultaneous biaxial continuous stretching apparatus is preferable.
As the simultaneous biaxial continuous stretching apparatus, a known one can be used, but a tenter type stretching machine that continuously stretches by fixing the long side with a chuck fitting and simultaneously stretching the distance in the vertical and horizontal directions is preferable. As a method for adjusting the degree of stretching, a screw method or a pantograph method can be used, but a pantograph method is more preferable from the viewpoint of accuracy of adjustment. When stretching while heating, it is preferable to provide a preheating zone before the stretched portion and a heat setting zone behind the stretched portion.

Further, the sheet may be a multilayer sheet in which a resin sheet not containing conductive particles and containing at least an insulating resin is laminated.
Preferably, the biaxially stretchable film is a long film, and the adhesive sheet is also a long adhesive sheet. In the present application, the long length means that the length is 10 m or more. If a long adhesive sheet is used, a connection structure can be produced continuously, which is efficient.
The adhesive sheet is an adhesive layer comprising a curing agent and a curable insulating resin, and this adhesive sheet is usually formed on a peelable base film (holding film). For this reason, the anisotropically conductive adhesive sheet obtained is normally formed on the peelable base film. It is also possible to form a cover film for preventing adhesion of dust and the like.
In the present specification, a laminate of the anisotropic conductive adhesive sheet, the base film, and the cover film may be referred to as an anisotropic conductive adhesive sheet. However, the value that defines the thickness of the anisotropic conductive adhesive sheet refers to the value excluding the thickness of the base film.

  As the pressure-sensitive adhesive used for the pressure-sensitive adhesive layer, known ones can be used. However, when biaxial stretching is performed while heating, it is preferable to use a non-thermal crosslinkable pressure-sensitive adhesive. Specifically, natural rubber latex adhesives, synthetic rubber latex adhesives, synthetic resin emulsion adhesives, silicone adhesives, ethylene-vinyl acetate copolymer adhesives, etc. may be used alone or in combination. Can do.

  The thickness of the adhesive layer is preferably in the range of 1/50 to 3 times the average particle diameter of the conductive particles used, more preferably in the range of 1/10 to 2 times, and still more preferably in the range of 1/5 to 1 time. It is. From the viewpoint of retaining the conductive particles when the conductive particles are adhered and when the insulating particle layer is formed, the thickness of the adhesive layer is preferably 1/50 or more of the average particle diameter of the conductive particles, and the transfer to the adhesive sheet after stretching is possible. From the viewpoint, it is preferably 3 times or less. As the method for forming the adhesive layer, a method in which a dispersion or solution in a solvent or water is applied and dried by a known method such as a gravure coater, a die coater, a knife coater, or a bar coater can be used. When a hot-melt type pressure-sensitive adhesive is used, it can be roll-coated without a solvent.

  In applying the conductive particles to the adhesive layer, it is preferable to dispose the conductive particles in a single layer (close packing) with almost no gap. As a method for dense packing, the above-described method of dispersing and arranging conductive particles on a biaxially stretchable film can be used. In addition, close packing means filling so that the average particle | grain space | interval between the filled particles may be 1/2 or less of an average particle diameter. More preferably, the average particle interval between the filled particles is 1/5 or less of the average particle size.

  As a method for forming the insulating particle layer on the conductive particle adhesion film, a known method can be used. Preferably, it is a method of applying and drying a composition containing at least insulating particles, an insulating resin, and a solvent on the conductive particle-adhering film. As a coating method, a known coating method such as a die coater, a blade coater, or a comma coater can be used. From the viewpoint of coating on an uneven conductive particle-adhered film, it is preferable to use a non-contact die coater. A curable resin and a curing agent may be blended in the insulating particle layer formed on the conductive particle adhesion film. In this case, it is preferable to use a latent curing agent from the viewpoint of storage stability.

The film thickness of the insulating particle layer is such that the value obtained by dividing the formed film thickness by the draw ratio is 1.5 times or less, preferably 1 time or less, more preferably 0.7 times the average particle diameter of the conductive particles. It is preferable to form.
The film thickness of the biaxially stretched film is preferably 1/10 to 1 times the total thickness of the adhesive sheet to be transferred and the base film of the adhesive sheet, and 1/5 to 1/2. It is particularly preferred that From the viewpoint of handling properties of the stretched film, it is preferably 1/10 or more, and from the viewpoint of transfer to the adhesive sheet after stretching, it is preferably 1 time or less.

Next, the connection method of the present invention, in which an electronic circuit component having fine connection terminals and a circuit board having a corresponding circuit are electrically connected with an anisotropic conductive adhesive sheet, will be described.
The electronic circuit component and a circuit board having a corresponding circuit are electrically connected using the anisotropic conductive adhesive sheet of the present invention.

  The height of the fine connection terminal is preferably 3 to 15 times and 40 μm or less of the average particle interval of the conductive particles, and preferably 4 to 10 times. Three times or more is preferable from the viewpoint of the mechanical strength of the fine connection structure, and the conductive particles move due to the resin flow of the adhesive sheet at the time of connection, and the connectivity due to the decrease in the number of conductive particles under the fine connection terminals. From the viewpoint of reduction, it is 15 times or less and preferably 40 μm or less.

  The fine connecting terminal interval is preferably 1 to 10 times the average particle interval and 40 μm or less, preferably 1 to 10 times and 20 μm or less, and more preferably 2 to 5 times and 15 μm or less. 1 times or more is preferable from the viewpoint of insulation, and 10 times or less and 40 μm or less are preferable from the viewpoint of fine connection. The pitch is 3 to 30 times the average particle interval and 80 μm or less, and preferably 5 to 20 times and 40 μm or less. It is preferably 3 times or more from the viewpoint of connectivity, and preferably 30 times or less and 80 μm or less from the viewpoint of fine connection.

The present invention also relates to a fine connection structure connected by the fine connection method.
The material of the circuit board constituting the finely connected structure of the present invention may be an organic substrate or an inorganic substrate. As the organic substrate, a polyimide film substrate, a polyamide film substrate, a polyethersulfone film substrate, a rigid substrate obtained by impregnating a glass cloth with an epoxy resin, a rigid substrate obtained by impregnating a glass cloth with a bismaleimide-triazine resin, or the like may be used. it can. As the inorganic substrate, a silicon substrate, a glass substrate, an alumina substrate, an aluminum nitride substrate, or the like can be used.

  The wiring material of the wiring board is inorganic wiring materials such as indium tin oxide and indium zinc oxide, metal wiring materials such as gold-plated copper, chromium-copper, aluminum and gold bumps, and metal materials such as aluminum and chromium indium tin oxide. A composite wiring material covering an inorganic wiring material such as an object can be used.

  As an application to which the anisotropic conductive adhesive sheet of the present invention is applied, or as an electronic circuit component constituting the finely connected structure of the present invention, a wiring board of a display device such as a liquid crystal display device, a plasma display device, an electroluminescence display device, etc. It can be used for connection applications, electronic component mounting applications such as LSIs for those devices, wiring board connection parts of other devices, and electronic component mounting applications such as LSIs. Among the display devices, it is preferably used for plasma display devices and electroluminescence display devices that require reliability.

Next, the present invention will be described with reference to examples and comparative examples.
First, a method for measuring the melt viscosity of the resin composition used in the examples and comparative examples will be described.
(Melt viscosity measurement method)
It measured using the E-type viscosity meter (HAAKE company make, RHeoStress600, 20 mm diameter cone use).

[Example 1]
90 g of phenoxy resin (glass transition temperature 84 ° C., number average molecular weight 9500), 10 g of bisphenol A type liquid epoxy resin (epoxy equivalent 190, viscosity at 25 ° C., 14000 mPa · s) as an insulating resin, γ-glycidoxypropyltrimethoxysilane 0 300 g of ethyl acetate was mixed with a composition comprising .25 g and 18.9 g of melamine formaldehyde condensate (substantially spherical fine particles, average particle size 2 μm, specific gravity 1.5 g / cm ³ ) to obtain a varnish for an insulating particle layer. A composition excluding the insulating particles from the above composition was applied onto a polyethylene terephthalate film having a thickness of 50 μm and air-dried at 60 ° C. for 15 minutes to obtain a sheet having a thickness of 18 μm.
The 180 ° C. melt viscosity of this sheet was measured and found to be 2000 Pa · s. This melt viscosity corresponds to the viscosity of the resin composition obtained by removing conductive particles and insulating particles from the first resin composition.

  Acetic acid is 42 g of phenoxy resin (glass transition temperature 89 ° C., number average molecular weight 11,000), 25 g of bisphenol A type epoxy resin (epoxy equivalent 190, 25 ° C. viscosity, 14000 mPa · s), 0.4 g of γ-glycidoxypropyltrimethoxysilane. Dissolve in a mixed solvent of ethyl-toluene (mixing ratio 1: 1) to obtain a 50% solid content solution. Disperse 33 g of liquid epoxy resin containing microcapsule-type latent imidazole curing agent (average particle size of microcapsule 5 μm, active temperature 125 ° C., liquid epoxy resin) (containing 22 g of liquid epoxy resin) in 50% solid content solution. I let you. Then, it apply | coated on the 50-micrometer-thick polyethylene terephthalate film (base film), air-dried at 60 degreeC for 15 minute (s), and the film-like adhesive sheet A with a film thickness of 18 micrometers was obtained.

  Separately, 22 g of bisphenol A type epoxy resin was mixed and dispersed in place of 33 g of the liquid epoxy resin containing the microcapsule-type latent imidazole curing agent to prepare an adhesive sheet B having a thickness of 1.0 μm. The produced adhesive sheet B had a 180 ° C. melt viscosity of 16.1 Pa · s. This melt viscosity corresponds to the melt viscosity of the resin composition obtained by removing the curing agent from the second resin composition.

Gold-plated plastic particles having an average particle diameter of 4.0 μm on a non-stretched copolymer polypropylene film having a thickness of 100 μm and a 5 μm thickness of a nitrile rubber latex-methyl methacrylate graft copolymer adhesive applied as an adhesive layer (Conductive particles) was applied as a single layer with almost no gap. That is, the conductive particles are prepared in a container having a thickness of several layers or more in a container larger than the film width, and the adhesive particles are pressed and adhered to the conductive particles with the application surface of the adhesive facing downward. Then, excess particles were scraped off with a scrubber made of soft rubber. The filling rate was 79%.
By repeating this operation twice, a conductive particle adhesion film coated with a single layer without a gap was obtained. The insulating particle layer varnish was applied on the anisotropic conductive adhesive sheet, dried at 70 ° C. for 20 minutes to form an insulating particle layer having a thickness of 10 μm, and a stretched film was produced.

This film was fixed with 10 chucks in the vertical and horizontal directions using a biaxial stretching device (Toyo Seiki X6H-S, pantograph type corner stretching type biaxial stretching device), preheated at 145 ° C. for 120 seconds, Thereafter, the film was stretched 2.3 times and fixed at a rate of 5% / second to obtain a stretched sheet C.
When the cross section of the stretched sheet C was observed using a scanning electron microscope (S-4700, manufactured by Hitachi, Ltd.), the thickness of the insulating particle layer was 2.1 μm, and the protruding top of the conductive particles was 0.9 μm thick. It was covered with resin. When the range of 100 μm × 100 μm was observed from the surface of the stretched sheet using a laser microscope, the number of insulating particles at the top of the conductive particles was zero. The number of insulating particles in the range of 100 μm × 100 μm was 591. The number of conductive particles measured in the same manner was 128, and the number of insulating particles was 4.6 times the number of conductive particles. The ratio in which the insulating particles were present without being in contact with other insulating particles was 64%.

  The adhesive sheet A was laminated on the stretched sheet C and laminated under the conditions of 60 ° C. and 0.4 MPa, and then the propylene film and the pressure-sensitive adhesive were peeled off. The said adhesive sheet B was laminated | stacked on the peeling surface, and it laminated on the conditions of 55 degreeC and 0.3 MPa, and obtained the anisotropically conductive adhesive sheet. As a result of observing with a laser microscope from the insulating particle uneven surface of the anisotropic conductive adhesive sheet about the location where the number of insulating particles was measured in the stretched sheet C before lamination, it was confirmed that neither the conductive particles nor the insulating particles were moved.

Among the conductive particles of the obtained anisotropic conductive adhesive sheet, 100 particles were selected at random, and a laser microscope (VK9500, manufactured by Keyence Corporation, shape measurement resolution 0.01 μm) capable of measuring displacement in the focal direction was used. The distance from the anisotropic conductive adhesive sheet surface was measured. As a result, it was found that 99% of the conductive particles were present within a range of 6 μm from the anisotropic conductive adhesive sheet surface. As a result of observation with an optical microscope, 98% of 100 conductive particles were single particles. Further, the average particle interval was 6.3 μm, which was 1.58 times the average particle size.
Further, the cross section of the anisotropic conductive adhesive sheet was observed with a scanning electron microscope, and the insulating particle existence region was measured in a range of 100 μm in length. The average of these 10 locations was found to be 2.4 μm.

[Comparative Example 1]
A stretched sheet D was obtained in the same manner as in Example 1 except that the insulating particles were removed from the insulating particle layer varnish. The thickness of the resin layer of the stretched sheet was 2.2 μm, and the thickness of the protruding top portion of the conductive particles was covered with a resin of 0.8 μm. Further, an adhesive sheet E was obtained in the same manner as in Example 1 except that 18.8 g of melamine formaldehyde condensate (substantially spherical fine particles, average particle diameter 2 μm, specific gravity 1.5 g / cm ³ ) was dispersed and mixed. An anisotropic conductive adhesive sheet was obtained in the same manner as in Example 1 except that the stretched sheet D and the adhesive sheet E were used. When the cross section of the anisotropic conductive adhesive sheet was observed with a scanning electron microscope and measured, it was 18 μm.

[Comparative Example 2]
A stretched sheet F was obtained in the same manner as in Example 1 except that the insulating particle layer was not formed. A melamine formaldehyde condensate (substantially spherical fine particles, an average particle size of 0.35 μm, a specific gravity of 1.5 g / cm ³ ) is sprayed on the stretched sheet F, and then an adhesive sheet A is laminated, under the conditions of 55 ° C. and 0.3 MPa. Laminated. Thereafter, the polypropylene film and the pressure-sensitive adhesive were peeled off to obtain an anisotropic conductive adhesive sheet. When the number of insulating particles was measured with a laser microscope from the back surface of the anisotropic conductive adhesive sheet, it was 1,651. Further, the cross section of the anisotropic conductive adhesive film was observed with a scanning electron microscope, and the existence region of the insulating particles was measured, and it was 0.38 μm.
The obtained anisotropic conductive adhesive sheet is a sheet lacking the one corresponding to the second layer in the present invention.

(Connection resistance measurement method)
After an oxide film is formed on the entire surface of a silicon piece (thickness 0.5 mm) having a length and width of 1.6 mm × 15.1 mm, an aluminum thin film (1000 A) having a width of 74.5 μm and a length of 120 μm is formed on the inner side by 40 μm. 175 pieces are formed on the long side and 16 pieces are formed on the short side, respectively, so as to have an interval of 1 μm. In order to form two gold bumps (thickness: 15 μm) each having a width of 25 μm and a length of 100 μm on the aluminum thin film at intervals of 15 μm, a width of 10 μm inside 7.5 μm from the outer peripheral portion of each gold bump placement location. Then, a polyimide protective film is formed on the entire surface other than the opening by a conventional method except for leaving the opening having a length of 85 μm. Thereafter, the gold bump is formed to obtain a test chip.

  A tantalum thin film (0.8 μm) is connected on a non-alkali glass with a thickness of 0.7 mm so that gold bumps on the aluminum thin film are paired with gold bumps on an adjacent aluminum thin film, and then indium tin oxide is oxidized. A connection pad (horizontal 66 μm, vertical 120 μm) of the material film (1400A) is formed. Each time 20 gold bumps are connected, an indium tin oxide thin film lead wiring is formed on the connection pad, and an aluminum titanium thin film (titanium 1%, 3000 mm) is formed on the lead wiring to form a connection evaluation board. . A side of the anisotropic conductive adhesive sheet having a width of 2 mm and a length of 17 mm is temporarily stretched on the connection evaluation substrate so as to cover all the connection pads, and a pressure bonding of 2.5 mm width is performed. After pressing with a head at 80 ° C., 0.3 MPa for 3 seconds, the polyethylene terephthalate base film is peeled off. There, a test chip is placed at a position where the position of the connection pad and the gold bump is deviated by 15 μm in the direction of the adjacent bump, and pressure bonding is performed at 200 ° C. for 10 seconds at 30 kg / cm 2. After the crimping, the resistance value between the lead wires (daisy chain of 20 gold bumps) is measured with a four-terminal resistance meter to obtain a connection resistance value.

(Insulation resistance test method)
A connection pad of a tantalum thin film (0.8 μm) followed by an indium tin oxide film (1400A) in such a positional relationship that two gold bumps on the aluminum thin film are connected to a non-alkali glass having a thickness of 0.7 mm. Width 65 μm, length 120 μm). A connection wiring of an indium tin oxide thin film is formed so that every other five connection pads can be connected, and a pair of them is paired to form a comb pattern so that every fifth connection pad can be connected. Then, an indium tin oxide thin film connection wiring is formed. A lead wire of indium tin oxide thin film (1400 mm) is formed on each connection wire, and an aluminum titanium thin film (titanium 1%, 3000 mm) is formed on the lead wire to obtain an insulating evaluation substrate. On the insulating evaluation substrate, an anisotropic conductive adhesive sheet having a width of 2 mm and a length of 17 mm is temporarily stretched so as to cover all the connection pads, and a pressure head having a width of 2.5 mm is used. After pressurizing at 0.3 MPa for 3 seconds, the polyethylene terephthalate base film is peeled off. Then, a test chip is placed at a position where the position of the connection pad and the gold bump is deviated by 15 μm in the direction of the adjacent bump, and pressure bonding is performed at 200 ° C. for 10 seconds at 30 kg / cm 2 to obtain an insulation resistance test substrate.

While maintaining this insulation resistance test substrate at 105 ° C., 1.2 atm, and saturated humidity, a DC voltage of 30 V is applied between the pair of lead wires using a constant voltage constant current power source. The insulation resistance between the wires is measured every 5 minutes, the time until the insulation resistance value becomes 10 MΩ or less is measured, and the value is defined as the insulation decrease time. The case where the insulation decrease time is less than 120 hours is indicated as x, and the case where it is 120 hours or more is indicated as ◯.
The results are shown in Table 1. As is clear from Table 1, the anisotropic conductive adhesive sheet of the present invention exhibits very excellent insulation reliability.

  The anisotropic conductive adhesive sheet of the present invention exhibits low connection resistance and high insulation reliability, and is suitable as a connection material for bare chip connection materials that require fine circuit connection and high-definition display devices.

It is the schematic which shows the structure of the cross section of the anisotropically conductive adhesive sheet of this invention.

Explanation of symbols

1 Curing agent and curable insulating resin (second layer)
2 Insulating particles 3 Precious metal coating 4 Resin particles 5 Insulating particle existence region (first layer)
6 conductive particles 7 base film

Claims (11)

  A first layer comprising a first resin composition containing at least conductive particles, insulating particles and an insulating resin, and a second layer comprising a second resin composition containing at least a curing agent and a curable insulating resin. An anisotropic conductive adhesive sheet comprising: the first layer is present in a region within 1.5 times the average particle size of the conductive particles along the thickness direction from the surface on one side, The thickness of the thinnest part of the first layer is smaller than the average particle diameter of the conductive particles, and the melt viscosity at 180 ° C. of the first resin composition is the melt viscosity at 180 ° C. of the second resin composition. An anisotropic conductive adhesive sheet characterized by being higher.   The melt viscosity at 180 ° C. of the first resin composition is in the range of 1,500 Pa · s to 20,000 Pa · s, and 30 to 150 times the melt viscosity at 180 ° C. of the second resin composition. The anisotropic conductive adhesive sheet according to claim 1, wherein the anisotropic conductive adhesive sheet is in the range.   The average particle size of the conductive particles is 2 to 8 μm, the average particle interval between adjacent conductive particles is 20 μm or less, and the thickness of the anisotropic conductive adhesive sheet is 1.5 times the average particle interval. The anisotropic conductive adhesive sheet according to claim 1, wherein the anisotropic conductive adhesive sheet is 40 μm or less.   The average particle size of the insulating particles is not less than 0.1 times and not more than 0.7 times the average particle size of the conductive particles, and 50% or more of the number of insulating particles exists without being in contact with other insulating particles. The anisotropic conductive adhesive sheet according to any one of claims 1 to 3.   The anisotropic conductive adhesive sheet according to any one of claims 1 to 4, wherein the number of insulating particles is in the range of 2 to 200 times the number of conductive particles. The anisotropic conductive adhesive sheet according to any one of claims 1 to 5, wherein 90% or more of the conductive particles are present without being in contact with other conductive particles.   An adhesive layer is provided on a biaxially stretchable film to form a laminate, and conductive particles having an average particle size of 2 to 8 μm are adhered onto the laminate to produce a conductive particle-adhered film. A resin composition layer containing at least insulating particles is formed on the conductive particles of the conductive particle-attached film, and the average particle interval between the conductive particles is 0.5 to 5 times the average particle size of the conductive particles. The biaxially stretched and held so that the conductive particles and the stretched sheet containing the insulating particles are transferred to an adhesive sheet containing at least a curing agent and a curable insulating resin. The manufacturing method of the anisotropically conductive adhesive sheet characterized by including the process to produce.   The method for producing an anisotropic conductive adhesive sheet according to claim 6, wherein the biaxially stretchable film is a long film, and the adhesive sheet is a long adhesive sheet.   A first circuit member having a first connection terminal and a second circuit member having a second connection terminal are disposed so that the first connection terminal and the second connection terminal are opposed to each other, and the opposed arrangement is performed. The anisotropic conductive adhesive sheet according to any one of claims 1 to 6 is interposed between the first connection terminal and the second connection terminal, and the first connection terminal disposed oppositely by heating and pressing. A circuit terminal connection method, wherein the second connection terminal is electrically connected.   The first circuit member having the first connection terminal and the second circuit member having the second connection terminal are arranged to face the first connection terminal and the second connection terminal, and The anisotropic conductive adhesive sheet according to any one of claims 1 to 6 is interposed between a first connection terminal and a second connection terminal arranged to face each other, and the first connection terminal arranged to face the other A circuit terminal connection structure in which the second connection terminal is electrically connected.   A finely connected structure comprising an electronic circuit component and a circuit board connected by the anisotropic conductive adhesive sheet according to claim 1.

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