WO2018101106A1 - 異方性導電フィルム - Google Patents

異方性導電フィルム Download PDF

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Publication number
WO2018101106A1
WO2018101106A1 PCT/JP2017/041684 JP2017041684W WO2018101106A1 WO 2018101106 A1 WO2018101106 A1 WO 2018101106A1 JP 2017041684 W JP2017041684 W JP 2017041684W WO 2018101106 A1 WO2018101106 A1 WO 2018101106A1
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WIPO (PCT)
Prior art keywords
conductive particles
hardness
resin layer
insulating resin
particles
Prior art date
Application number
PCT/JP2017/041684
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English (en)
French (fr)
Inventor
康二 江島
堅一 平山
怜司 塚尾
Original Assignee
デクセリアルズ株式会社
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Filing date
Publication date
Priority claimed from JP2017160655A external-priority patent/JP7039883B2/ja
Application filed by デクセリアルズ株式会社 filed Critical デクセリアルズ株式会社
Priority to KR1020197014344A priority Critical patent/KR102250339B1/ko
Priority to US16/464,854 priority patent/US10985128B2/en
Priority to KR1020217013457A priority patent/KR102519781B1/ko
Priority to CN201780071308.7A priority patent/CN109983629B/zh
Publication of WO2018101106A1 publication Critical patent/WO2018101106A1/ja

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    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/20—Conductive material dispersed in non-conductive organic material
    • H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
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    • H01B5/14—Non-insulated conductors or conductive bodies characterised by their form comprising conductive layers or films on insulating-supports
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    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
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    • H05K2203/02—Details related to mechanical or acoustic processing, e.g. drilling, punching, cutting, using ultrasound
    • H05K2203/0278—Flat pressure, e.g. for connecting terminals with anisotropic conductive adhesive

Definitions

  • the present invention relates to an anisotropic conductive film.
  • An anisotropic conductive film in which conductive particles are dispersed in an insulating resin layer is widely used for mounting electronic components such as IC chips.
  • an oxide film is formed on the surface of a terminal of an electronic component connected with an anisotropic conductive film, the connection resistance is increased.
  • use of conductive particles having different particle diameters to lower the resistance by breaking through the oxide film (Patent Document 1), or using hard conductive particles to cause the conductive particles to bite into the wiring.
  • the connection area is increased (Patent Document 2).
  • Patent Document 1 When conductive particles having different particle sizes are used as described in Patent Document 1, particles smaller than particles having a large particle size bite into the terminal, but it is difficult to sufficiently reduce the resistance. In addition, if hard conductive particles are used as described in Patent Document 2, it is necessary to perform pressure bonding at high pressure during anisotropic conductive connection, and the connection structure between the substrate and the IC chip obtained by anisotropic conductive connection is required. Deformation and cracks may occur.
  • the present invention uses conductive particles with high hardness so that even a terminal having an oxide film can be connected, and enables crimping under low pressure conditions and confirms the capture of the conductive particles at the terminal.
  • the object is to make it easy and to reliably reduce the resistance.
  • the contact pressure concentrates on the high-hardness conductive particles during anisotropic conductive connection, and the high-hardness conductive particles break through the oxide film.
  • the high-hardness conductive particles contribute to conduction by utilizing the cracks formed in the oxide film. Therefore, even if the particle density of the high-hardness conductive particles is lowered, the conduction at the terminals is not limited to the high-hardness conductive particles and the low-hardness conductive particles.
  • the present invention has been conceived by finding that it is possible to eliminate this problem, and that, by using a mixture of high-hardness conductive particles and low-hardness conductive particles, the indentation of the conductive particles can be easily observed.
  • the present invention provides an insulating resin layer with high-hardness conductive particles having a 20% compression modulus of 8000 to 28000 N / mm 2 as conductive particles and low-hardness conductive particles having a 20% compression modulus lower than that of the high-hardness conductive particles.
  • An electrically conductive film is provided.
  • the anisotropic conductive film of the present invention even if an oxide film is formed on the surface of the terminal of the electronic component, the high-hardness conductive particles bite into the oxide film, and the high-hardness conductive particles formed on the oxide film. Since the low-hardness conductive particles contribute to conduction at the terminal due to the crack, the conduction resistance can be reduced.
  • the low-hardness conductive particles are mixed with the high-hardness conductive particles, the pressure-bonding force required at the time of anisotropic conductive connection can be reduced as compared with the case where the conductive particles are made of only the high-hardness conductive particles. . Therefore, it is possible to prevent deformation and cracks from occurring in the connection structure having anisotropic conductive connection.
  • connection structure with anisotropic conductive connection both the indentation of the high-hardness conductive particles and the indentation of the low-hardness conductive particles can be observed, and in particular, the indentation of the high-hardness conductive particles can be clearly observed.
  • the number of trapped conductive particles at the terminal can be accurately evaluated. Therefore, it is possible to reliably reduce the resistance.
  • FIG. 1A is a plan view showing the arrangement of conductive particles in an anisotropic conductive film 10A according to an embodiment of the present invention.
  • FIG. 1B is a cross-sectional view of the anisotropic conductive film 10A of the example.
  • FIG. 2A is a plan view showing the arrangement of conductive particles in the anisotropic conductive film 10B of one embodiment of the present invention.
  • FIG. 2B is a cross-sectional view of the anisotropic conductive film 10B of the example.
  • FIG. 3 is a cross-sectional view of the anisotropic conductive film 10C of the example.
  • FIG. 4 is a cross-sectional view of the anisotropic conductive film 10D of the example.
  • FIG. 1A is a plan view showing the arrangement of conductive particles in an anisotropic conductive film 10A according to an embodiment of the present invention.
  • FIG. 1B is a cross-sectional view of the anisotropic conductive film 10A of the example.
  • FIG. 5 is a cross-sectional view of the anisotropic conductive film 10E of the example.
  • FIG. 6 is a cross-sectional view of the anisotropic conductive film 10F of the example.
  • FIG. 7 is a cross-sectional view of the anisotropic conductive film 10G of the example.
  • FIG. 8 is a cross-sectional view of the anisotropic conductive film 100A of the example.
  • FIG. 9 is a cross-sectional view of the anisotropic conductive film 100B of the example.
  • FIG. 10A is a cross-sectional view of the anisotropic conductive film 100C of the example.
  • FIG. 10B is a cross-sectional view of the anisotropic conductive film 100C ′ of the example.
  • FIG. 11 is a cross-sectional view of the anisotropic conductive film 100D of the example.
  • FIG. 12 is a cross-sectional view of the anisotropic conductive film 100E of the example.
  • FIG. 13 is a cross-sectional view of the anisotropic conductive film 100F of the example.
  • FIG. 14 is a cross-sectional view of the anisotropic conductive film 100G of the example.
  • FIG. 15 is a cross-sectional view of an anisotropic conductive film 100X for comparison.
  • FIG. 1A is a plan view illustrating the arrangement of conductive particles 1A and 1B in an anisotropic conductive film 10A according to an embodiment of the present invention.
  • FIG. 1B is an xx cross-sectional view of the anisotropic conductive film 10A.
  • the anisotropic conductive film 10A includes a high-hardness conductive particle 1A having a 20% compression modulus of 8000 to 28000 N / mm 2 and a low-hardness conductive particle 1B having a 20% compression modulus lower than that of the high-hardness conductive particle 1A. Both are formed from the conductive particle dispersion layer 3 dispersed in the insulating resin layer 2.
  • the total number density of the conductive particles including the high-hardness conductive particles 1A and the low-hardness conductive particles 1B is 6000 / mm 2 or more, of which the number density of the low-hardness conductive particles 1B accounts for 10% or more of the total conductive particles. Yes.
  • the conductive particles as a whole have a square lattice arrangement, there is no regularity as to which of the high-hardness conductive particles 1A and the low-hardness conductive particles 1B is located at each lattice point.
  • the conductive particle dispersion layer 3 includes both high-hardness conductive particles 1A and low-hardness conductive particles 1B as conductive particles.
  • the high-hardness conductive particles 1A have a 20% compression modulus of 8000 to 28000 N / mm 2 .
  • the 20% compressive elastic modulus is a measurement of a compression variable of a conductive particle when a compressive load is applied to the conductive particle using a micro compression tester (for example, Fischer Scope H-100 manufactured by Fischer Instruments).
  • 20% compressive elastic modulus (K) (N / mm 2 ) (3/2 1/2 ) ⁇ F ⁇ S -3 / 2 ⁇ R -1/2
  • the K value calculated by can be used.
  • F Load value when the conductive particles are 20% compressively deformed (N)
  • S Compression displacement (mm) when conductive particles are 20% compressively deformed
  • R radius of conductive particles (mm) It is.
  • the high-hardness conductive particles can break through the oxide film. , 28000 N / mm 2 or less, the pressure-bonding force required at the time of anisotropic conductive connection is not excessively increased, and anisotropic conductive connection can be performed using a conventional pressing jig.
  • the particle diameter of the high-hardness conductive particles 1A is preferably 1 ⁇ m or more and 30 ⁇ m or less, more preferably 3 ⁇ m or more and less than 10 ⁇ m, in order to suppress an increase in conduction resistance and suppress the occurrence of a short circuit.
  • the particle size of the conductive particles before being dispersed in the insulating resin layer can be measured by a general particle size distribution measuring device, and the average particle size can also be obtained using the particle size distribution measuring device. It may be an image type or a laser type. As an example of the image type measuring apparatus, a wet flow type particle diameter / shape analyzer FPIA-3000 (Malvern) can be mentioned.
  • the number of samples (number of conductive particles) for measuring the average particle diameter D is preferably 1000 or more.
  • the particle diameter of the conductive particles in the anisotropic conductive film can be determined from observation with an electron microscope such as SEM. In this case, it is desirable that the number of samples for measuring the average particle diameter is 200 or more.
  • the particle size of the conductive particles in the present invention means a particle size not including the insulating fine particles on the surface.
  • the low-hardness conductive particles 1B have a 20% compression modulus lower than that of the high-hardness conductive particles, and preferably 10% or more and 70% or less of the 20% compression modulus of the high-hardness conductive particles. If the 20% compression elastic modulus of the low-hardness conductive particles 1B is too low, it will be difficult to contribute to conduction, while if it is too high, the difference in hardness from the high-hardness conductive particles will be insufficient, and the effects of the present invention will not be obtained.
  • the particle diameter of the low-hardness conductive particles 1B is preferably 1 ⁇ m or more and 30 ⁇ m or less, and there is no practical problem as long as it is 80% or more with respect to the particle diameter of the high-hardness conductive particles, but it is preferably equal or larger.
  • the high-hardness conductive particles 1A and the low-hardness conductive particles 1B having the above-described hardness and particle diameter can be appropriately selected from the conductive particles used in known anisotropic conductive films.
  • conductive particles used in known anisotropic conductive films examples thereof include metal particles such as nickel, cobalt, silver, copper, gold and palladium, alloy particles such as solder, metal-coated resin particles, and metal-coated resin particles having insulating fine particles attached to the surface.
  • the thickness of the metal layer in the metal-coated resin particles is preferably 50 nm to 250 nm.
  • the conductive particles may be provided with protrusions on the surface. In the case of metal-coated resin particles, those listed in JP-A-2016-89153 may be used.
  • the number density of the low-hardness conductive particles 1B is 10% or more of the entire conductive particles, and can be adjusted as appropriate depending on the type of terminal to be connected and the connection conditions. As an example, it is preferably 20% or more and 80% or less, and more preferably 30% or more and 70% or less. Even if the number density of the low-hardness conductive particles relative to the whole conductive particles is too low or too high, it is difficult to obtain the effect of the present invention by mixing the high-hardness conductive particles and the low-hardness conductive particles.
  • the number density of the entire conductive particles is not particularly limited.
  • the average particle diameter D of the entire conductive particles 1A and 1B is less than 10 ⁇ m, it is preferably 6000 / mm 2 or more and 42000 / mm. 2 or less.
  • the average particle diameter is 10 ⁇ m or more, the range is not limited. As an example, it is 20 pieces / mm 2 or more and 2000 pieces / mm 2 or less.
  • the area occupancy is an index of the thrust required for the pressing jig for thermocompression bonding of the anisotropic conductive film to the electronic component. By making this area occupancy preferably 35% or less, more preferably 0.3 to 30%, the thrust required for the pressing jig for thermocompression bonding of the anisotropic conductive film to the electronic component Can be kept low.
  • the number density of the conductive particles can be measured using an observation image obtained with a metal microscope or the like. Alternatively, the observation image may be measured and obtained by image analysis software (for example, WinROOF, Mitani Corporation, etc.).
  • image analysis software for example, WinROOF, Mitani Corporation, etc.
  • a plurality of rectangular regions preferably 5 or more, more preferably 10 or more rectangular regions each having a side of 100 ⁇ m or more are set, and the total area of the measurement regions is 2 mm. Two or more are preferable. What is necessary is just to adjust suitably the magnitude
  • the average of the planar view area of one electroconductive particle can be calculated
  • the observation method and the measurement method are not limited to the above-described methods.
  • the interparticle distance Lg as the whole of the conductive particles 1A and 1B is appropriately set according to a predetermined number density and particle arrangement after the above-described area occupation ratio of the conductive particles 1A and 1B is achieved. .
  • the arrangement of the entire conductive particles including the high-hardness conductive particles 1A and the low-hardness conductive particles 1B in a plan view of the film may be regular or random.
  • the regular arrangement include a lattice arrangement such as a hexagonal lattice, an orthorhombic lattice, and a rectangular lattice in addition to the square lattice shown in FIG. 1A.
  • particle rows in which the conductive particles 1A or 1B are linearly arranged at predetermined intervals may be arranged in parallel at predetermined intervals.
  • the regular arrangement is not particularly limited as long as it is repeated in the longitudinal direction of the film.
  • each of the high-hardness conductive particles 1A and the low-hardness conductive particles 1B may be regularly arranged.
  • the number density of the low-hardness conductive particles 1B is 50% of the total conductive particles
  • the high-hardness conductive particles 1A and the low-hardness conductive particles 1B are respectively Can be a square lattice array.
  • the high-hardness conductive particles 1A and the low-hardness conductive particles 1B are alternately arranged, but the present invention includes such a strict arrangement and an arrangement that is not so.
  • the lattice axis or the arrangement axis may be parallel to the longitudinal direction of the anisotropic conductive film 10A, and the longitudinal direction of the anisotropic conductive film Crossing may be performed and can be determined according to the terminal width to be connected, the terminal pitch, and the like.
  • the longitudinal direction of the anisotropic conductive film 10A may be parallel to the longitudinal direction of the anisotropic conductive film 10A, and the longitudinal direction of the anisotropic conductive film Crossing may be performed and can be determined according to the terminal width to be connected, the terminal pitch, and the like.
  • an anisotropic conductive film for fine pitch is used, as shown in FIG. 1A, at least one lattice axis A of the conductive particles 1A and 1B is skewed with respect to the longitudinal direction of the anisotropic conductive film 10A.
  • the angle ⁇ formed by the longitudinal direction of the terminal 20 connected by the anisotropic conductive film 10A and the lattice axis A is preferably
  • the conductive particles 1A and 1B exist without contacting each other in a plan view of the film, and the conductive particles 1A and 1B exist without overlapping each other in the film thickness direction. Therefore, the ratio of the number of conductive particles 1A and 1B existing in non-contact with each other with respect to the entire conductive particles is 95% or more, preferably 98% or more, more preferably 99.5% or more. This is the same for both regular and random arrangements. As will be described later, it is preferable to arrange the conductive particles 1A and 1B regularly using a transfer mold because the proportion of the conductive particles 1A and 1B existing in non-contact with each other can be easily controlled.
  • the positions in the film thickness direction are aligned.
  • the embedding amount Lb of the conductive particles 1A, 1B in the film thickness direction can be made uniform as shown in FIG. 1B. That is, since the distance from one interface of the insulating resin layer 2 can be made uniform, the trapping property of the conductive particles at the terminal is easily stabilized.
  • the conductive particles 1A, 1B are embedded from the surface of the insulating resin layer 2 by embedding the conductive particles 1A, 1B in the insulating resin layer 2.
  • the distance to 1B is the same, the trapping property of the conductive particles at the terminal tends to be stable for the same reason as described above.
  • the conductive particles 1A, 1B are exposed from the insulating resin layer 2 as in the case of the recesses 2b and 2c described later. Since the resistance of the insulating resin layer 2 to the deformation of the metal-coated resin particles caused by the pressing of the metal-coated resin particles by the pressing jig is reduced, the state of the indentation after connection tends to be uniform. Thereby, it becomes easy to confirm the state after connection.
  • the embedding amount Lb is the surface of the insulating resin layer 2 in which the conductive particles 1A and 1B are embedded (the side of the front and back surfaces of the insulating resin layer 2 where the conductive particles 1A and 1B are exposed). Or when the conductive particles 1A and 1B are completely embedded in the insulating resin layer 2, the distance between the conductive particles 1A and 1B is close to the center portion between adjacent conductive particles. The distance between the tangent plane 2p in FIG. 2 and the deepest part of the conductive particles 1A and 1B.
  • the embedding rate is preferably 30% or more and 105% or less.
  • the embedding rate (Lb / D) is 30% or more and less than 60%, the ratio of the exposed particles from the resin having a relatively high viscosity that holds the conductive particles is increased, so that low-pressure mounting is facilitated.
  • the conductive particles 1A and 1B can be easily maintained in a predetermined particle dispersion state or a predetermined arrangement by the insulating resin layer 2.
  • the resin amount of the insulating resin layer which acts so that the electrically-conductive particle between terminals may flow unnecessarily at the time of anisotropic conductive connection can be reduced.
  • the conductive particles 1A and 1B may penetrate the insulating resin layer 2, and the filling rate (Lb / D) in that case is 100%.
  • the value of the embedding rate (Lb / D) is 80% or more, preferably 90% or more, more preferably 96% or more of the total number of conductive particles contained in the anisotropic conductive film. It means that it is a numerical value of the embedding rate (Lb / D). Therefore, the embedding rate of 30% or more and 105% or less means that the embedding rate of 30% or more, preferably 90% or more, more preferably 96% or more of the total number of conductive particles contained in the anisotropic conductive film is 30. % Or more and 105% or less.
  • the embedding ratio (Lb / D) of all the conductive particles is uniform, the load of pressing is uniformly applied to the conductive particles, so that the state of capturing the conductive particles at the terminal is improved, and the conduction reliability is improved. Can be expected. In order to increase accuracy, 200 or more conductive particles may be measured and obtained.
  • the measurement of the embedding rate (Lb / D) can be obtained collectively for a certain number by adjusting the focus in the surface field image.
  • a laser type discrimination displacement sensor manufactured by Keyence Co., Ltd. may be used for measuring the embedding rate (Lb / D).
  • the minimum melt viscosity of the insulating resin layer 2 is not particularly limited, and is appropriately determined according to the use object of the anisotropic conductive film, the method for manufacturing the anisotropic conductive film, and the like. be able to.
  • the thickness may be about 1000 Pa ⁇ s depending on the method for manufacturing the anisotropic conductive film.
  • the insulating resin layer is a film. It is preferable that the minimum melt viscosity of the insulating resin layer is 1100 Pa ⁇ s or more from the viewpoint of enabling molding.
  • a recess 2b is formed around the exposed portions of the conductive particles 1A and 1B pushed into the insulating resin layer 2, From the point of forming the recess 2c directly above the conductive particles 1A and 1B pushed into the insulating resin layer 2 as shown in FIG. 5, it is preferably 1500 Pa ⁇ s or more, more preferably 2000 Pa ⁇ s or more, more preferably 3000 to 15000 Pa ⁇ s, even more preferably 3000 to 10000 Pa ⁇ s.
  • This minimum melt viscosity can be obtained using a rotary rheometer (manufactured by TA Instruments Inc.) as an example, kept constant at a measurement pressure of 5 g, and using a measurement plate having a diameter of 8 mm, and more specifically in the temperature range. At 30 to 200 ° C., it can be obtained by setting the temperature rising rate 10 ° C./min, the measurement frequency 10 Hz, and the load fluctuation 5 g with respect to the measurement plate.
  • the minimum melt viscosity of the insulating resin layer 2 By setting the minimum melt viscosity of the insulating resin layer 2 to a high viscosity of 1500 Pa ⁇ s or more, unnecessary movement of the conductive particles can be suppressed for pressure bonding of the anisotropic conductive film to the article. It is possible to prevent the conductive particles to be sandwiched between the terminals sometimes from being caused to flow due to the resin flow.
  • the insulating resin layer 2 when the conductive particles 1A and 1B are pressed is When the conductive particles 1A and 1B are pushed into the insulating resin layer 2 so that the conductive particles 1A and 1B are exposed from the insulating resin layer 2, the insulating resin layer 2 is plastically deformed to form the conductive particles 1A and 1B.
  • the surrounding insulating resin layer 2 is made of a viscous material having a high viscosity such that the dent 2b (FIG.
  • the viscosity at 60 ° C. of the insulating resin layer 2 is preferably at least 3000 Pa ⁇ s, more preferably at least 4000 Pa ⁇ s, further preferably at least 4500 Pa ⁇ s, and the upper limit is preferably at most 20000 Pa ⁇ s.
  • This measurement is performed by the same measurement method as that for the minimum melt viscosity, and can be obtained by extracting a value at a temperature of 60 ° C.
  • the specific viscosity of the insulating resin layer 2 when the conductive particles 1A and 1B are pressed into the insulating resin layer 2 is preferably set to 3000 Pa ⁇ in accordance with the shape and depth of the recesses 2b and 2c to be formed. s or more, more preferably 4000 Pa ⁇ s or more, further preferably 4500 Pa ⁇ s or more, and the upper limit is preferably 20000 Pa ⁇ s or less, more preferably 15000 Pa ⁇ s or less, and even more preferably 10000 Pa ⁇ s or less. Further, such a viscosity is preferably obtained at 40 to 80 ° C., more preferably 50 to 60 ° C.
  • the recesses 2b (FIG. 4) are formed around the conductive particles 1A and 1B exposed from the insulating resin layer 2, the conductivity generated when the anisotropic conductive film is pressed onto the article.
  • the resistance received from the insulating resin against the flattening of the particles 1A and 1B is reduced as compared with the case where there is no dent 2b. For this reason, it becomes easy for the conductive particles to be sandwiched between the terminals at the time of anisotropic conductive connection, so that the conduction performance is improved and the trapping property is improved.
  • the recess 2c (FIG. 5) is formed on the surface of the insulating resin layer 2 immediately above the conductive particles 1A and 1B embedded without being exposed from the insulating resin layer 2, there is no recess 2c.
  • the pressure at the time of press-bonding the anisotropic conductive film to the article is easily concentrated on the conductive particles 1A and 1B. For this reason, the trapping property is improved because the conductive particles are easily held between the terminals at the time of anisotropic conductive connection, and the conduction performance is improved.
  • the anisotropic conductive film 100A is composed of the conductive particle dispersion layer 3 (FIG. 8).
  • the conductive particle dispersion layer 3 the high-hardness conductive particles 1 ⁇ / b> A and the low-hardness conductive particles 1 ⁇ / b> B are regularly dispersed on one side of the insulating resin layer 2.
  • the conductive particles 1A and 1B are not in contact with each other, and the conductive particles 1A and 1B are regularly dispersed in the film thickness direction without overlapping each other.
  • a single-layer conductive particle layer having a uniform position is formed.
  • an inclination 2b is formed with respect to the tangential plane 2p of the insulating resin layer 2 at the center between adjacent conductive particles.
  • undulations 2c may be formed on the surface of the insulating resin layer immediately above the conductive particles 1A and 1B embedded in the insulating resin layer 2 ( 11 and 13).
  • inclination means that the flatness of the surface of the insulating resin layer is impaired in the vicinity of the conductive particles 1A and 1B, and a part of the resin layer is missing from the tangential plane 2p to reduce the amount of resin. It means the state that is. In other words, in the inclination, the surface of the insulating resin layer around the conductive particles is missing with respect to the tangent plane.
  • “undulation” means a state where the surface of the insulating resin layer directly above the conductive particles has undulations, and the resin is reduced due to the presence of a portion having a height difference such as undulations.
  • the amount of resin in the insulating resin layer directly above the conductive particles is smaller than when the surface of the insulating resin layer directly above the conductive particles is in a tangential plane.
  • the conductive particles 1A and 1B are connected to the terminals during anisotropic conductive connection. Since the resistance received from the insulating resin layer with respect to the flattening of the conductive particles 1A and 1B generated when sandwiched between them is reduced as compared with the case where there is no inclination 2b, the conductive particles are easily sandwiched at the terminal. As a result, the conduction performance is improved and the trapping property is improved. This inclination is preferably along the outer shape of the conductive particles.
  • the anisotropic conductive film has a variety of electronic parts to be connected, and as long as it is tuned according to these, it is desired that the degree of freedom of design is high enough to satisfy various requirements, so the inclination or undulation is reduced. It can be used even if it disappears or partially disappears.
  • the undulations 2c are formed on the surface of the insulating resin layer 2 immediately above the conductive particles 1A and 1B buried without being exposed from the insulating resin layer 2, As in the case, a pressing force from the terminal is easily applied to the conductive particles during anisotropic conductive connection.
  • the amount of resin directly above the conductive particles is reduced compared to when the resin is deposited flat due to undulations, the resin directly above the conductive particles at the time of connection is more likely to be removed, and the terminal and conductive Since it becomes easy to come into contact with the particles, the capturing property of the conductive particles at the terminal is improved, and the conduction reliability is improved.
  • the positions of the conductive particles 1A and 1B in the thickness direction of the insulating resin layer 2 when the viewpoint of “inclination” or “undulation” is taken into consideration are as follows. Although it may be exposed or may be embedded in the insulating resin layer 2 without being exposed, the distance of the deepest part of the conductive particles from the tangential plane 2p in the central part between the adjacent conductive particles (hereinafter referred to as the following)
  • the ratio (Lb / D) (hereinafter referred to as “embedding ratio”) between Lb and the average particle diameter D of the conductive particles is preferably 30% or more and 105% or less.
  • the conductive particles 1A and 1B are maintained in a predetermined particle dispersion state or a predetermined arrangement by the insulating resin layer 2, and are set to 105% or less.
  • the amount of resin in the insulating resin layer that acts to cause the conductive particles between the terminals to flow unnecessarily during anisotropic conductive connection it is possible to reduce the amount of resin in the insulating resin layer that acts to cause the conductive particles between the terminals to flow unnecessarily during anisotropic conductive connection.
  • the numerical value of the embedding rate (Lb / D) is 80% or more, preferably 90% or more, more preferably 96% or more of the total number of conductive particles contained in the anisotropic conductive film. Lb / D). Therefore, the embedding rate of 30% to 105% means that the embedding rate of 80% or more, preferably 90% or more, more preferably 96% or more of the total number of conductive particles contained in the anisotropic conductive film is 30%. It means more than 105%.
  • the embedding ratio (Lb / D) of all the conductive particles is uniform, the load of pressing is uniformly applied to the conductive particles, so that the state of capturing the conductive particles at the terminal is improved, and the conduction reliability is improved. Will improve.
  • the embedding rate (Lb / D) was determined by arbitrarily extracting 10 or more regions having an area of 30 mm 2 or more from the anisotropic conductive film, observing a part of the film cross section with an SEM image, and totaling 50 or more conductive particles. Can be obtained by measuring In order to increase accuracy, 200 or more conductive particles may be measured and obtained.
  • the measurement of the embedding rate (Lb / D) can be obtained collectively for a certain number by adjusting the focus in the surface field image.
  • a laser type discrimination displacement sensor manufactured by Keyence Co., Ltd. may be used for measuring the embedding rate (Lb / D).
  • the anisotropic conductive film 100A has a portion of the surface of the insulating resin layer 2 that is in contact with the conductive particles 1A and 1B exposed from the insulating resin layer 2 and the vicinity thereof between adjacent conductive particles. It has the inclination 2b used as the ridgeline in general along the external shape of an electroconductive particle with respect to the tangent plane 2p in the surface 2a of the insulating resin layer of a center part.
  • Such an inclination 2b or undulation 2c described later is obtained by pressing the conductive particles 1A and 1B when the anisotropic conductive film 100A is manufactured by pressing the conductive particles 1A and 1B into the insulating resin layer 2. It can be formed by carrying out at a viscosity of 3000 to 20000 Pa ⁇ s, more preferably 4500 to 15000 Pa ⁇ s at ⁇ 80 ° C.
  • the anisotropic conductive film 100A has a portion of the surface of the insulating resin layer 2 that is in contact with the conductive particles 1A and 1B exposed from the insulating resin layer 2 and the vicinity thereof between adjacent conductive particles. It has the inclination 2b used as the ridgeline in general along the external shape of an electroconductive particle with respect to the tangent plane 2p in the surface 2a of the insulating resin layer of a center part.
  • Such an inclination 2b or undulation 2c described later is a viscosity when the conductive particles 1A and 1B are pressed when the anisotropic conductive film 100A is manufactured by pressing the conductive particles 1A and 1B into the insulating resin layer 2.
  • the lower limit is preferably 3000 Pa ⁇ s or more, more preferably 4000 Pa ⁇ s or more, further preferably 4500 Pa ⁇ s or more
  • the upper limit is preferably 20000 Pa ⁇ s or less, more preferably 15000 Pa ⁇ s or less, still more preferably. 10000 Pa ⁇ s or less.
  • such a viscosity is preferably obtained at 40 to 80 ° C., more preferably 50 to 60 ° C.
  • a part of the slope 2b and the undulation 2c may be lost by heat-pressing the insulating resin layer, the slope 2b may be changed to the undulation 2c, and the conductive particles having the undulation 2c are The insulating resin layer 2 may be exposed at one point on the top.
  • the embedding rate (Lb / D) of 100% is around the conductive particles 1A and 1B as in the anisotropic conductive film 100B shown in FIG.
  • Lc is smaller than the average particle diameter D of the conductive particles, as in the anisotropic conductive film 100C shown in FIG.
  • the slope 2b around the exposed portions of the conductive particles 1A and 1B is in the vicinity of the conductive particles 1A and 1B. It appears abruptly and is shallow on the surface of the insulating resin layer 2 as in the anisotropic conductive film 100D shown in FIG. 11, in which the exposed diameter Lc of the conductive particles 1A and 1B and the average particle diameter D of the conductive particles are substantially equal. There are undulations 2c, conductive particles 1A, 1 There can be mentioned those that are exposed from the insulating resin layer 2 at one point of the top 1a.
  • a minute protruding portion 2q may be formed adjacent to the slope 2b of the insulating resin layer 2 around the exposed portion of the conductive particles and the undulation 2c of the insulating resin layer immediately above the conductive particles. An example of this is shown in FIG. 10B.
  • the embedding rate (Lb / D) is approximately 80 to 105%, particularly 90 to 100%, the top portions 1a of the conductive particles 1A and 1B embedded in the insulating resin layer 2 and the insulating resin Although it can be said that it is flush with the surface 2a of the layer 2, the movement of the conductive particles due to the resin flow can be reduced.
  • 100D is less conductive around the conductive particles 1A and 1B.
  • the movement of the particles can be eliminated, and the conductive particles 1A and 1B are exposed from the insulating resin layer 2 even at one point on the top portion 1a. You can expect the effect that even slight movements are difficult to occur. Therefore, this aspect is particularly effective when the fine pitch and the space between the bumps are narrow.
  • the anisotropic conductive films 100B (FIG. 9), 100C (FIG. 10A), and 100D (FIG. 11) having different shapes and depths of the slope 2b and the undulation 2c are formed by pushing the conductive particles 1A and 1B, as will be described later. It can be manufactured by changing the viscosity of the insulating resin layer 2 at the time.
  • the conductive particles 1A and 1B are exposed as in the anisotropic conductive film 100E shown in FIG. Examples thereof include a slope 2b with respect to the tangential plane 2p of the resin layer 2 or a undulation 2c (FIG. 13) with respect to the tangential plane 2p of the insulating resin layer 2 immediately above the conductive particles 1A and 1B.
  • the anisotropic conductive film 100E (FIG. 12) which has the inclination 2b in the insulating resin layer 2 around the exposed part of the conductive particles 1A and 1B and the insulating resin layer 2 immediately above the conductive particles 1A and 1B are undulated 2c.
  • the anisotropic conductive film 100F (FIG. 13) having the above can be manufactured by changing the viscosity or the like of the insulating resin layer 2 when the conductive particles 1A and 1B are pressed when manufacturing them.
  • the anisotropic conductive film 100E shown in FIG. 12 is used for anisotropic conductive connection, since the conductive particles 1A and 1B are directly pressed from the terminals, the trapping property of the conductive particles at the terminals is improved. Further, when the anisotropic conductive film 100F shown in FIG. 13 is used for anisotropic conductive connection, the conductive particles 1A and 1B do not directly press the terminal, but press the insulating resin layer 2, The amount of resin present in the pressing direction is as shown in FIG.
  • the conductive particles 1A and 1B are embedded with an embedding rate exceeding 100%, and the conductive particles 1A and 1B are not exposed from the insulating resin layer 2, And the surface of the insulating resin layer 2 is flat), it is easy to apply a pressing force to the conductive particles, and the conductive particles 1A and 1B between the terminals are unnecessary due to the resin flow at the time of anisotropic conductive connection. Is prevented from moving to.
  • the ratio (Le / D) between the maximum depth Le of the slope 2b and the average particle diameter D of the conductive particles 1A and 1B (Le / D) is preferably less than 50%, more preferably less than 30% from the viewpoint of easily obtaining the effect of 13).
  • the ratio (Ld / D) between the maximum diameter Ld of the slope 2b and the undulation 2c and the average particle diameter D of the conductive particles 1A and 1B is preferably 100% or more, more preferably The ratio (Lf / D) between the maximum depth Lf of the undulations 2c and the average particle diameter D of the conductive particles 1A, 1B is greater than 0, preferably less than 10%, more preferably 5%. It is as follows.
  • the diameter Lc of the exposed (immediately above) portions of the conductive particles 1A and 1B in the slope 2b and the undulations 2c can be made equal to or smaller than the average particle size D of the conductive particles 1A and 1B, and preferably 10 to 90%.
  • the conductive particles 1A and 1B may be exposed at one point on the top, or the conductive particles 1A and 1B may be completely embedded in the insulating resin layer 2 so that the diameter Lc becomes zero.
  • the conductive particles 1A and 1B are likely to roll on the insulating resin layer 2, and therefore anisotropic. From the point of improving the capture rate at the time of conductive conductive connection, it is preferable that the filling rate (Lb / D) is 60% or more.
  • the presence of the slope 2b and the undulation 2c on the surface of the insulating resin layer 2 can be confirmed by observing the cross section of the anisotropic conductive film with a scanning electron microscope, and the surface field observation. Can also be confirmed.
  • the tilt 2b and the undulation 2c can be observed even with an optical microscope or a metal microscope.
  • the size of the slope 2b and the undulation 2c can be confirmed by adjusting the focus during image observation. The same applies even after the inclination or undulation is reduced by heat pressing as described above. This is because traces may remain.
  • the insulating resin layer 2 is preferably formed from a curable resin composition, and can be formed from, for example, a thermopolymerizable composition containing a thermopolymerizable compound and a thermal polymerization initiator. You may make a thermopolymerizable composition contain a photoinitiator as needed.
  • thermopolymerizable compound When a thermal polymerization initiator and a photopolymerization initiator are used in combination, one that functions as both a thermopolymerizable compound and a photopolymerizable compound may be used, and a photopolymerizable compound is contained separately from the thermopolymerizable compound. You may let them.
  • a photopolymerizable compound is contained separately from the thermally polymerizable compound.
  • a thermal cationic polymerization initiator is used as the thermal polymerization initiator
  • an epoxy compound is used as the thermal polymerizable compound
  • a radical photopolymerization initiator is used as the photopolymerization initiator
  • an acrylate compound is used as the photopolymerizable compound.
  • the photopolymerization initiator As the photopolymerization initiator, a plurality of types that react to light having different wavelengths may be contained. Accordingly, the wavelength used for the photocuring of the resin constituting the insulating resin layer during the production of the anisotropic conductive film and the photocuring of the resin for bonding the electronic components to each other during the anisotropic conductive connection. Can be used properly.
  • photocuring during the production of the anisotropic conductive film, all or part of the photopolymerizable compound contained in the insulating resin layer can be photocured.
  • this photocuring the arrangement of the conductive particles 1A and 1B in the insulating resin layer 2 is maintained or fixed, and it is expected that the short circuit is suppressed and the capture is improved.
  • this photocuring is preferably performed when the ratio (La / D) between the layer thickness La of the insulating resin layer 2 and the average particle diameter D of the conductive particles 1A and 1B is less than 0.6.
  • the insulating resin layer 2 can more reliably hold or fix the arrangement of the conductive particles and adjust the viscosity of the insulating resin layer 2. This is in order to suppress a decrease in yield in the connection between electronic components using an anisotropic conductive film.
  • the blending amount of the photopolymerizable compound in the insulating resin layer is preferably 30% by mass or less, more preferably 10% by mass or less, and more preferably less than 2% by mass. This is because when the amount of the photopolymerizable compound is too large, the thrust applied to the pushing at the time of connection increases.
  • thermally polymerizable composition examples include a thermal radical polymerizable acrylate composition containing a (meth) acrylate compound and a thermal radical polymerization initiator, and a thermal cationic polymerizable epoxy system containing an epoxy compound and a thermal cationic polymerization initiator.
  • thermal cationic polymerizable epoxy composition containing a thermal cationic polymerization initiator examples include compositions.
  • a thermal anionic polymerizable epoxy composition containing a thermal anionic polymerization initiator may be used.
  • a plurality of kinds of polymerizable compounds may be used in combination as long as they do not cause any trouble. Examples of the combination include a combination of a cationic polymerizable compound and a radical polymerizable compound.
  • the (meth) acrylate compound a conventionally known thermal polymerization type (meth) acrylate monomer can be used.
  • a monofunctional (meth) acrylate monomer or a bifunctional or higher polyfunctional (meth) acrylate monomer can be used.
  • thermal radical polymerization initiator examples include organic peroxides and azo compounds.
  • organic peroxides that does not generate nitrogen that causes bubbles can be preferably used.
  • the amount of the thermal radical polymerization initiator used is preferably 2 to 60 parts by weight, more preferably 100 parts by weight of the (meth) acrylate compound. 5 to 40 parts by mass.
  • the epoxy compound examples include a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a novolac type epoxy resin, a modified epoxy resin thereof, an alicyclic epoxy resin, and the like. it can.
  • an oxetane compound may be used in combination.
  • thermal cationic polymerization initiator those known as thermal cationic polymerization initiators for epoxy compounds can be employed.
  • thermal cationic polymerization initiators for epoxy compounds.
  • iodonium salts, sulfonium salts, phosphonium salts, ferrocenes, etc. that generate an acid by heat are used.
  • an aromatic sulfonium salt showing a good potential with respect to temperature can be preferably used.
  • the amount of the thermal cationic polymerization initiator used is preferably 2 to 60 mass relative to 100 parts by mass of the epoxy compound. Part, more preferably 5 to 40 parts by weight.
  • the thermopolymerizable composition preferably contains a film-forming resin and a silane coupling agent.
  • the film-forming resin include phenoxy resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, urethane resin, butadiene resin, polyimide resin, polyamide resin, polyolefin resin, and the like. be able to.
  • a phenoxy resin can be preferably used from the viewpoints of film formability, processability, and connection reliability.
  • the weight average molecular weight is preferably 10,000 or more.
  • the silane coupling agent include an epoxy silane coupling agent and an acrylic silane coupling agent. These silane coupling agents are mainly alkoxysilane derivatives.
  • the thermally polymerizable composition may contain an insulating filler in addition to the above-described conductive particles 1A and 1B.
  • an insulating filler examples include silica powder and alumina powder.
  • a fine filler having an insulating filler particle size of 20 to 1000 nm is preferable, and the blending amount is preferably 5 to 50 parts by mass with respect to 100 parts by mass of a thermally polymerizable compound (photopolymerizable compound) such as an epoxy compound. .
  • the anisotropic conductive film of the present invention contains a filler, softener, accelerator, anti-aging agent, colorant (pigment, dye), organic solvent, ion catcher agent, etc. in addition to the above-mentioned insulating filler. You may let them.
  • the ratio (La / D) between the layer thickness La of the insulating resin layer 2 and the average particle diameter D of the conductive particles 1A, 1B is set to a lower limit of 0.3 or more for the reason described later.
  • the upper limit can be made 10 or less. Therefore, the ratio is preferably 0.3 to 10, more preferably 0.6 to 8, and still more preferably 0.6 to 6.
  • the average particle diameter D of the conductive particles 1A and 1B means the average particle diameter.
  • the conductive particles 1A and 1B are likely to be displaced due to resin flow during anisotropic conductive connection, and the trapping property of the conductive particles 1A and 1B at the terminal is lowered. Since this tendency is remarkable when this ratio (La / D) exceeds 10, 8 or less is more preferable, and 6 or less is still more preferable.
  • the conductive particles 1A and 1B are dispersed in a predetermined particle state or a predetermined state by the insulating resin layer 2.
  • the ratio (La / D) is preferably 0.3 or more, and 0.6 or more from the point that the insulating resin layer 2 reliably maintains a predetermined particle dispersion state or a predetermined arrangement. Is more preferable.
  • the ratio (La / D) between the layer thickness La of the insulating resin layer 2 and the average particle diameter D of the conductive particles 1A, 1B is preferably 0.8-2. is there.
  • La / D is 3.5 or less, preferably 2.5 or less, more preferably 2 or less with respect to the upper limit, and 0.8 or more with respect to the lower limit. Preferably it is 1 or more, more preferably more than 1.3.
  • the conductive particles 1A and 1B are hardly pressed against the terminals during anisotropic conductive connection. At the same time, the conductive particles are easily flowed by the resin flow. For this reason, the conductive particles are easily displaced, and the trapping property of the conductive particles at the terminal is lowered. Further, the thrust required for the pressing jig to press the conductive particles against the terminals also increases, which hinders low-pressure mounting. On the contrary, if the layer thickness La of the insulating resin layer 2 is too small and this ratio is excessively small, it is difficult to maintain the conductive particles 1A and 1B in a predetermined arrangement by the insulating resin layer 2.
  • a second insulating resin layer 4 having a minimum melt viscosity lower than that of the resin constituting the insulating resin layer 2 can be laminated on the conductive particle dispersion layer 3 (see FIG. 6, FIG. 7).
  • the second insulating resin layer 4 fills a space formed by terminals such as bumps of the electronic component at the time of anisotropic conductive connection, and can improve the adhesion between the opposing electronic components.
  • the particle trapping properties of the conductive particles 1A and 1B In order to improve the thickness of the insulating resin layer 2, it is desirable to increase the viscosity of the insulating resin layer 2 and reduce the thickness of the insulating resin layer 2 as long as the conductive particles 1 ⁇ / b> A and 1 ⁇ / b> B are not displaced. When the thickness of 2 is excessively thin, there is a concern about a decrease in adhesiveness because the amount of resin for adhering opposing electronic components is insufficient.
  • the adhesion between the electronic components can be improved, and the second insulating resin layer 2 can be improved. Since the fluidity of the conductive resin layer 4 is higher than that of the insulating resin layer 2, it is possible to make it difficult to prevent the conductive particles 1A and 1B from being held and pushed by the terminals.
  • the electronic component pressed with a tool is used regardless of whether the second insulating resin layer 4 is on the formation surface of the recess 2b. It is preferable that the second insulating resin layer 4 is attached (the insulating resin layer 2 is attached to an electronic component placed on the stage). By doing in this way, unnecessary movement of the conductive particles can be avoided and the trapping property can be improved.
  • the space formed by the electrodes and bumps of the electronic component is more easily filled with the second insulating resin layer 4.
  • the adhesion between the electronic components can be improved.
  • the amount of movement of the insulating resin layer 2 present in the conductive particle dispersion layer 3 becomes relatively smaller as there is this difference, and the conductive particles 1A and 1B between the terminals are less likely to flow due to resin flow. This is preferable because the trapping property of the conductive particles 1A and 1B at the terminal is improved.
  • the minimum melt viscosity ratio between the insulating resin layer 2 and the second insulating resin layer 4 is preferably 2 or more, more preferably 5 or more, and still more preferably 8 or more. On the other hand, if this ratio is too large, there is a risk of the resin sticking out or blocking when a long anisotropic conductive film is used as a wound body.
  • the preferable minimum melt viscosity of the second insulating resin layer 4 more specifically satisfies the above-mentioned ratio, and is 3000 Pa ⁇ s or less, preferably 2000 Pa ⁇ s or less, particularly 100 to 2000 Pa ⁇ s. .
  • the second insulating resin layer 4 can be formed by adjusting the viscosity in the same resin composition as the insulating resin layer 2.
  • the layer thickness of the second insulating resin layer 4 is preferably 4 to 20 ⁇ m.
  • the average particle diameter D of the conductive particles 1A and 1B is preferably 1 to 8 times.
  • the minimum melt viscosity of the anisotropic conductive films 10F and 10G as a whole combining the insulating resin layer 2 and the second insulating resin layer 4 is practically 8000 Pa ⁇ s or less, preferably 200 to 7000 Pa ⁇ s, More preferably, it is 200 to 4000 Pa ⁇ s.
  • the conductive particles 1 ⁇ / b> A and 1 ⁇ / b> B protrude from one surface of the insulating resin layer 2 as in the anisotropic conductive film 10 ⁇ / b> F illustrated in FIG. 6.
  • the second insulating resin layer 4 can be laminated on the protruding surface, and the conductive particles 1A and 1B can be bitten into the second insulating resin layer 4.
  • the embedding rate (Lb / D) of the conductive particles 1A and 1B is 0.95 or less
  • the second insulating resin layer 4 is preferably laminated as described above, and more preferably 0.9 or less. .
  • the average particle diameter D is less than 10 ⁇ m, it may be desirable to do so.
  • the second insulating resin layer 4 is laminated on the surface opposite to the surface of the insulating resin layer 2 in which the conductive particles 1A and 1B are embedded. May be.
  • a third insulating resin layer may be provided on the opposite side across the second insulating resin layer 4 and the insulating resin layer 2.
  • the third insulating resin layer can function as a tack layer.
  • it may be provided to fill a space formed by the electrodes and bumps of the electronic component.
  • the resin composition, viscosity, and thickness of the third insulating resin layer may be the same as or different from those of the second insulating resin layer 4.
  • the minimum melt viscosity of the anisotropic conductive film obtained by combining the insulating resin layer 2, the second insulating resin layer 4, and the third insulating resin layer is not particularly limited, but is practically 8000 Pa ⁇ s or less, preferably Is 200 to 7000 Pa ⁇ s, more preferably 200 to 4000 Pa ⁇ s.
  • the conductive particles 1A and 1B are held on the surface of the insulating resin layer 2 in a predetermined regular arrangement or random dispersed state independently of each other, and the conductive particles 1A, It can be manufactured by pushing 1B into the insulating resin layer 2 with a flat plate or a roller.
  • the embedding amount Lb of the conductive particles 1A, 1B in the insulating resin layer 2 can be adjusted by the pressing force, temperature, etc. when the conductive particles 1A, 1B are pushed, and the presence or absence of the recesses 2b, 2c.
  • the shape and depth can be adjusted by the viscosity, indentation speed, temperature, etc. of the insulating resin layer 2 at the time of indentation.
  • the method of holding the conductive particles 1A and 1B on the insulating resin layer 2 is not particularly limited, but when the conductive particles 1A and 1B are regularly arranged, for example, a transfer mold is used.
  • the insulating resin layer 2 holds the conductive particles 1A and 1B mixed at a predetermined ratio.
  • a transfer mold for example, a known opening forming method such as a photolithographic method is used for an inorganic material such as silicon, various ceramics, glass, and stainless steel, and an organic transfer material such as various resins. Can be used.
  • the transfer mold can take a plate shape, a roll shape, or the like.
  • the conductive particles 1A and 1B of the insulating resin layer 2 are added to the resin composition forming the insulating resin layer 2 at a predetermined ratio.
  • An insulating resin layer in which the conductive particles 1A and 1B are in random positions may be obtained by kneading (mixing) and applying it onto a release film.
  • the anisotropic conductive film is preferably long to some extent. Therefore, the length of the anisotropic conductive film is preferably 5 m or more, more preferably 10 m or more, and further preferably 25 m or more. On the other hand, if the anisotropic conductive film is excessively long, it becomes impossible to use a conventional connection device used when an electronic component is manufactured using the anisotropic conductive film, and the handleability is also poor. Therefore, the length of the anisotropic conductive film is preferably 5000 m or less, more preferably 1000 m or less, and even more preferably 500 m or less. Such a long body of the anisotropic conductive film is preferably a wound body wound around a core from the viewpoint of excellent handleability.
  • the anisotropic conductive film of the present invention anisotropically conducts first electronic components such as IC chips, IC modules, and FPCs and second electronic components such as FPCs, glass substrates, plastic substrates, rigid substrates, and ceramic substrates. It can be preferably used when connecting, and particularly as a plastic substrate, there can be mentioned a substrate in which a terminal is formed on a PET base material that is likely to be deformed or cracked by pressure bonding at high pressure.
  • the PET substrate may be a laminate of polyimide substrates with an adhesive. These total thickness can be 0.15 mm or less as an example.
  • the anisotropic conductive film of the present invention may be used to stack IC chips and wafers to make a multilayer.
  • the electronic component connected with the anisotropic conductive film of this invention is not limited to the above-mentioned electronic component. It can be used for various electronic parts that have been diversified in recent years.
  • the present invention also includes a connection structure in which electronic components are anisotropically conductively connected using the anisotropic conductive film of the present invention.
  • the manufacturing method of the connection structure which has the process of arrange
  • the resin layer of the anisotropic conductive film is a single layer of the conductive particle dispersion layer 3, it is anisotropic to the second electronic component such as various substrates.
  • the conductive particles 1A, 1B of the conductive conductive film are temporarily attached from the side where the conductive particles 1B are embedded on the surface, and are temporarily pressure-bonded.
  • the first electronic component such as a chip can be combined and thermocompression bonded.
  • the insulating resin layer of the anisotropic conductive film contains not only a thermal polymerization initiator and a thermal polymerizable compound, but also a photopolymerization initiator and a photopolymerizable compound (may be the same as the thermal polymerizable compound), A pressure bonding method using both light and heat may be used. In this way, unintentional movement of the conductive particles can be minimized. Further, the side on which the conductive particles are not embedded may be temporarily attached to the second electronic component for use. Note that the anisotropic conductive film may be temporarily attached to the first electronic component instead of the second electronic component.
  • the anisotropic conductive film is formed of a laminate of the conductive particle dispersion layer 3 and the second insulating resin layer 4, the conductive particle dispersion layer 3 is temporarily attached to a second electronic component such as various substrates. Then, the first electronic component such as an IC chip is aligned and placed on the second insulating resin layer 4 side of the anisotropic conductive film that has been temporarily pressure-bonded, and thermocompression-bonded.
  • the second insulating resin layer 4 side of the anisotropic conductive film may be temporarily attached to the first electronic component.
  • the conductive particle dispersion layer 3 side can be temporarily attached to the first electronic component for use.
  • Examples 1 to 4 Comparative Examples 1 and 2 (1) Production of anisotropic conductive film
  • an insulating resin layer forming resin composition for forming a conductive particle dispersion layer and a second insulating resin layer forming resin composition were respectively prepared. Prepared.
  • the minimum melt viscosity of the insulating resin layer was 3000 Pa ⁇ s or more, and the ratio of the minimum melt viscosity of the insulating resin layer to the minimum melt viscosity of the second insulating resin layer was 2 or more.
  • high-hardness conductive particles (20% compression elastic modulus 22000 N / mm 2 ) having about 70 alumina particles (average particle diameter 150 nm) on the surface of the resin core particles and Ni layer (thickness 100 nm) as the outermost layer. And an average particle diameter of 3 ⁇ m (manufactured by Sekisui Chemical Co., Ltd.) (manufactured by the method described in Japanese Patent Application Laid-Open No. 2006-269296). Particles (20% compression modulus 6000 N / mm 2 , average particle diameter 3 ⁇ m, manufactured by Sekisui Chemical Co., Ltd.) were prepared. In the following Examples 1 to 24 and Comparative Examples 1 to 10, conductive particles manufactured by Sekisui Chemical Co., Ltd. were also prepared.
  • High hardness conductive particles and low hardness conductive particles are mixed with the resin composition for forming an insulating resin layer (high viscosity resin layer) so that the number density thereof is in the ratio shown in Table 2, and this is mixed with a film by a bar coater. It apply
  • the second insulating resin layer-forming resin composition was applied onto a PET film having a film thickness of 50 ⁇ m with a bar coater and dried in an oven at 80 ° C. for 5 minutes, whereby a thickness of 12 ⁇ m was formed on the PET film.
  • a resin layer to be the second insulating resin layer was formed. This resin layer was laminated on the above-mentioned conductive particle dispersion layer to obtain an anisotropic conductive film.
  • connection structure for an electronic component was prepared using the anisotropic conductive films of Examples and Comparative Examples produced in (1), which were cut in an area sufficient for connection, (A) Trapping efficiency, (b) indentation, (c) particle collapse rate, and (d) resistance value were evaluated as follows. The results are shown in Table 2.
  • Evaluation IC Outline 1.8 ⁇ 20.0mm Thickness 0.5mm Bump specifications Size 30 ⁇ 85 ⁇ m, distance between bumps 20 ⁇ m, bump surface material Au
  • the number of trapped high-hardness conductive particles and low-hardness conductive particles was measured for 100 terminal pairs after heating and pressing, and the average was obtained. Further, the theoretical values of the high-hardness conductive particles and the low-hardness conductive particles present on the terminals before heating and pressing are calculated from [terminal area for 100 terminals] ⁇ [number density of conductive particles] and measured. The ratio of the number of trapped conductive particles to the theoretical value was determined and evaluated according to the following criteria. In practical use, B evaluation or higher is preferable.
  • Criteria for evaluating capture efficiency A 30% or more B: 15% or more and less than 30% C: Less than 15%
  • (B) Indentation The indentations of the high-hardness conductive particles and the low-hardness conductive particles in the connection structure for evaluation manufactured in (a) were observed with a metal microscope, and the high-hardness conductive particles and low The indentation (capture) number of the hardness conductive particles was measured using image analysis software WinROOF (Mitani Corporation), and the average was obtained.
  • the theoretical values of the high-hardness conductive particles and low-hardness conductive particles present on the terminals before heating and pressing are calculated from [terminal area for five terminals] ⁇ [number density of conductive particles] and measured. The ratio of the number of indentations (trapping) of the conductive particles to the theoretical value was determined and evaluated according to the following criteria.
  • the confirmed indentations are about 100 indentations of five bumps in a dispersed anisotropic conductive film in which conductive particles are randomly arranged.
  • the conductive particles are arranged in a square lattice, which will be described later.
  • the indentation of the five bumps was about 200.
  • Indentation evaluation criteria OK When 50% or more of the theoretical value can be recognized as an indentation NG: When less than 50% of the theoretical value can be recognized as an indentation
  • Particle collapse rate (%) ([Average particle diameter before pressure bonding] ⁇ [Average particle diameter after pressure bonding]) ⁇ 100 / [Average particle diameter before pressure bonding]
  • Evaluation criteria for particle collapse rate at the initial stage and 500 hours A: 10% or more B: 5% or more and less than 10% C: less than 5%
  • Evaluation criteria for initial resistance value A Less than 3 ⁇ B: 3 ⁇ or more and less than 5 ⁇ C: 5 ⁇ or more and less than 10 ⁇ D: 10 ⁇ or more
  • Resistance value evaluation criteria at 500 h A Less than 3 ⁇ B: 3 ⁇ or more and less than 5 ⁇ C: 5 ⁇ or more and less than 10 ⁇ D: 10 ⁇ or more
  • Examples 5 to 8, Comparative Examples 3 and 4 The same conductive particles as in Example 1 were prepared. However, by adjusting the 20% compression elastic modulus of the resin core particles, as the high-hardness conductive particles, the conductive particles having a 20% compression elastic modulus of 14000 N / mm 2 (average particle diameter of 3 ⁇ m) and the low-hardness conductive particles, Conductive particles (average particle diameter of 3 ⁇ m) having a 20% compression modulus of 6000 N / mm 2 were prepared.
  • the high-hardness conductive particles are mixed with the resin composition for forming an insulating resin layer (high-viscosity resin layer) so that the ratio shown in Table 3 is the ratio of the high-hardness conductive particles and the low-hardness conductive particles.
  • An anisotropic conductive film in which particles and low-hardness conductive particles are randomly dispersed was produced.
  • Examples 9-12, Comparative Example 5 The same conductive particles as in Example 1 were prepared. However, by adjusting the 20% compressive elasticity modulus of the resin core particles, as a high-hardness conductive particles, 20% compressive elasticity modulus 9000 N / mm 2 of the conductive particles (average particle size 3 [mu] m), as a low hardness conductive particles, Conductive particles (average particle diameter of 3 ⁇ m) having a 20% compression modulus of 6000 N / mm 2 were prepared.
  • the high-hardness conductive particles and the low-hardness conductive particles were mixed in the insulating resin layer (high-viscosity resin layer) forming resin composition so as to have the ratio shown in Table 4, and the high-hardness conductive particles were the same as in Example 1.
  • An anisotropic conductive film in which particles and low-hardness conductive particles are randomly dispersed was produced.
  • a resin composition for forming an insulating resin layer for forming a conductive particle dispersion layer was prepared with the formulation shown in Table 1, and this was applied onto a PET film having a film thickness of 50 ⁇ m with a bar coater and placed in an oven at 80 ° C. For 5 minutes to form an insulating resin layer on the PET film. The thickness of this insulating resin layer was 6 ⁇ m.
  • the 2nd resin composition for insulating resin layer formation was prepared with the mixing
  • a mold is prepared so that the conductive particles have a square lattice arrangement as shown in FIG. 1A, and the total number density of the high-hardness conductive particles and the low-hardness conductive particles becomes the numerical value shown in Table 5,
  • a well-known transparent resin pellet was poured in a melted state, cooled and hardened to form a resin mold having an array pattern having recesses shown in FIG. 1A.
  • the resin-type recesses are filled with high-hardness conductive particles and low-hardness conductive particles so as to have the ratio shown in Table 5, and the above-mentioned insulating resin layer is placed thereon, and 60 ° C, 0. It stuck by pressing at 5 MPa. Then, the insulating resin layer is peeled from the mold, and the conductive particles on the insulating resin layer are pressed into the insulating resin layer (pressing conditions: 60 to 70 ° C., 0.5 MPa) to form a conductive particle dispersion layer. did. In this case, the filling rate was 99.9%.
  • the resin layer formed from the second resin composition for forming an insulating resin layer is laminated on the surface of the conductive particle dispersion layer in which the conductive particles are embedded, and the high-hardness conductive particles and the low-hardness conductive particles as a whole are laminated.
  • An anisotropic conductive film arranged in a square lattice was manufactured.
  • the anisotropic conductive film thus obtained was cut in an area sufficient for connection, and an evaluation connection structure was prepared in the same manner as in Example 1 using the cut anisotropic conductive film.
  • A Capture efficiency
  • B Indentation
  • c Particle collapse rate
  • d Resistance value was evaluated. The results are shown in Table 5.
  • Examples 17 to 20 Comparative Examples 8 and 9 20% compressive elasticity modulus as in Example 5 and a high-hardness conductive particles 14000N / mm 2, 20% compression modulus was prepared low hardness conductive particles of 6000 N / mm 2.
  • the high-hardness conductive particles and the low-hardness conductive particles are square as a whole in the same manner as in Example 13 except that the high-hardness conductive particles and the low-hardness conductive particles are mixed so as to have the ratio shown in Table 6 and filled in the resin mold.
  • An anisotropic conductive film arranged in a lattice was produced.
  • Examples 21 to 24 Comparative Example 10 20% compressive elasticity modulus as in Example 9 and a high-hardness conductive particles of 9000 N / mm 2, 20% compression modulus was prepared low hardness conductive particles of 6000 N / mm 2.
  • the high-hardness conductive particles and the low-hardness conductive particles are square as a whole in the same manner as in Example 13 except that the high-hardness conductive particles and the low-hardness conductive particles are mixed so as to have the ratio shown in Table 7 and filled in the resin mold.
  • An anisotropic conductive film arranged in a lattice was produced.
  • the anisotropic conductive film of Comparative Example 1 20% compression modulus contains only high-hardness conductive particles 22000N / mm 2 even 20% compression modulus only low hardness conductive particles of 6000 N / mm 2
  • the anisotropic conductive film of Comparative Example 2 containing Inferior also has poor indentation evaluation, and the anisotropic conductive film of Comparative Example 1 containing only high-hardness conductive particles has inferior conduction characteristics (500 h). Yes. From this, when the conductive particles are only low-hardness conductive particles, the hardness is insufficient, so that the indentation is difficult to see, and when the conductive particles are only high-hardness conductive particles, the conductive particles are too hard.
  • the indentation is difficult to see due to insufficient compression.
  • the indentation was easier to observe in the example in which the high-hardness conductive particles and the low-hardness conductive particles were mixed.
  • the 20% compression high hardness conductive particles modulus of elasticity 14000N / mm 2 20% compression modulus contain both a low hardness conductive particles of 6000 N / mm 2, the conductive particles are arranged at random It can be seen that the anisotropic conductive films of Examples 5 to 8 are all good in evaluation of indentation and good in conduction characteristics (initial resistance value, 500 h resistance value). In particular, the pressure at the time of anisotropic conductive connection is good even at a low pressure of 60 MPa.
  • the anisotropic conductive film of Comparative Example 3 containing only high-hardness conductive particles having a 20% compression modulus of 14000 N / mm 2 is inferior in the evaluation of indentation, and the pressure at the time of anisotropic conductive connection Is 60 MPa, the conduction characteristics (500 h) are also inferior.
  • the anisotropic conductive film of Comparative Example 4 containing only low-hardness conductive particles as conductive particles had a problem in indentation.
  • Table 4 also, a 20% compression modulus high hardness conductive particles of 9000 N / mm 2, anisotropic Examples 9-12 20% compression modulus containing both low hardness conductive particles of 6000 N / mm 2
  • Each of the conductive conductive films has a good evaluation of indentation, and has good conduction characteristics (initial resistance value, 500 h resistance value), and is particularly good even when the pressure during anisotropic conductive connection is as low as 60 MPa. I understand that.
  • the anisotropic conductive film of Comparative Example 5 containing only low-hardness conductive particles as conductive particles had a problem with indentation.

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Abstract

異方性導電フィルムは、絶縁性樹脂層２に導電粒子として２０％圧縮弾性率が８０００～２８０００Ｎ／ｍｍ2の高硬度導電粒子１Ａと、該高硬度導電粒子１Ａよりも２０％圧縮弾性率が低い低硬度導電粒子１Ｂが分散している構造を有する。導電粒子全体の個数密度は６０００個／ｍｍ2以上であり、低硬度導電粒子１Ｂの個数密度は導電粒子全体の１０％以上である。

Description

異方性導電フィルム
　本発明は、異方性導電フィルムに関する。
　ＩＣチップなどの電子部品の実装に、導電粒子を絶縁性樹脂層に分散させた異方性導電フィルムが広く使用されている。しかしながら、異方性導電フィルムで接続する電子部品の端子の表面に酸化皮膜が形成されていると、接続抵抗が高くなってしまう。これに対しては、粒子径の異なる導電粒子を使用して酸化皮膜を突き破ることにより低抵抗化を図ること（特許文献１）や、硬い導電粒子を使用することで導電粒子を配線に食い込ませ、接続面積を大きくして低抵抗化を図ること（特許文献２）等が提案されている。
特開２０１３－１８２８２３号公報 特開２０１２－１６４４５４号公報
　特許文献１に記載のように粒子径の異なる導電粒子を使用すると、粒子径の大きい粒子よりも小さい粒子が端子に食い込むが、これにより十分に低抵抗化を図ることは難しい。また、特許文献２に記載のように硬い導電粒子を使用すると、異方性導電接続時に高圧で圧着することが必要となり、異方性導電接続により得た基板とＩＣチップとの接続構造体に変形やクラックが生じる場合がある。
　変形やクラックの発生を防止するために導電粒子を減らす方法があるが、導電粒子を減らすと端子における導電粒子の捕捉数が減り、かえって高抵抗化したり、接続後の導通抵抗の上昇が引き起こされたりする。
　これに対し、本発明は、酸化皮膜が形成されている端子でも接続できるように高硬度の導電粒子を使用し、かつ低圧条件での圧着を可能とすると共に端子における導電粒子の捕捉の確認を容易とし、確実に低抵抗化を図れるようにすることを目的とする。
　本発明者は、硬度の異なる導電粒子を混合して使用すると、異方性導電接続時には高硬度導電粒子に接圧が集中し、高硬度導電粒子が酸化皮膜を突き破ること、低硬度導電粒子は、高硬度導電粒子が酸化皮膜に形成したクラックを利用して導通に寄与すること、したがって、高硬度導電粒子の粒子密度を下げても端子における導電には高硬度導電粒子と低硬度導電粒子の双方が寄与するので導通抵抗が下がること、また、高硬度導電粒子の粒子密度を下げることができるので、異方性導電接続時に高圧での圧着が不要となり、接続構造体に変形やクラックが発生する問題を解消できること、さらに、高硬度導電粒子と低硬度導電粒子を混合使用することにより、導電粒子の圧痕の観察が容易になることを見出し、本発明を想到した。
　即ち本発明は、絶縁性樹脂層に、導電粒子として２０％圧縮弾性率が８０００～２８０００Ｎ／ｍｍ2の高硬度導電粒子と、該高硬度導電粒子よりも２０％圧縮弾性率が低い低硬度導電粒子が分散している異方性導電フィルムであって、導電粒子全体の個数密度が６０００個／ｍｍ2以上であり、低硬度導電粒子の個数密度が導電粒子全体の１０％以上である異方性導電フィルムを提供する。
　本発明の異方性導電フィルムによれば、電子部品の端子の表面に酸化皮膜が形成されていても、高硬度導電粒子が酸化皮膜に食い込み、また、高硬度導電粒子が酸化皮膜に形成したクラックにより低硬度導電粒子も端子における導通に寄与するので、導通抵抗を低下させることができる。
　また、高硬度導電粒子に低硬度導電粒子が混合していることにより、導電粒子が高硬度導電粒子のみからなる場合に比して異方性導電接続時に必要な圧着力を低下させることができる。したがって、異方性導電接続した接続構造体に変形やクラックが発生することを防止できる。
　さらに、異方性導電接続した接続構造体では、高硬度導電粒子の圧痕も低硬度導電粒子の圧痕も観察することができ、特に、高硬度導電粒子の圧痕は鮮明に観察することができるので、端子における導電粒子の捕捉数を正確に評価することができる。よって、確実に低抵抗化を図ることができる。
図１Ａは、本発明の一実施例の異方性導電フィルム１０Ａにおける導電粒子の配置を示す平面図である。 図１Ｂは、実施例の異方性導電フィルム１０Ａの断面図である。 図２Ａは、本発明の一実施例の異方性導電フィルム１０Ｂにおける導電粒子の配置を示す平面図である。 図２Ｂは、実施例の異方性導電フィルム１０Ｂの断面図である。 図３は、実施例の異方性導電フィルム１０Ｃの断面図である。 図４は、実施例の異方性導電フィルム１０Ｄの断面図である。 図５は、実施例の異方性導電フィルム１０Ｅの断面図である。 図６は、実施例の異方性導電フィルム１０Ｆの断面図である。 図７は、実施例の異方性導電フィルム１０Ｇの断面図である。 図８は、実施例の異方性導電フィルム１００Ａの断面図である。 図９は、実施例の異方性導電フィルム１００Ｂの断面図である。 図１０Ａは、実施例の異方性導電フィルム１００Ｃの断面図である。 図１０Ｂは、実施例の異方性導電フィルム１００Ｃ′の断面図である。 図１１は、実施例の異方性導電フィルム１００Ｄの断面図である。 図１２は、実施例の異方性導電フィルム１００Ｅの断面図である。 図１３は、実施例の異方性導電フィルム１００Ｆの断面図である。 図１４は、実施例の異方性導電フィルム１００Ｇの断面図である。 図１５は、比較のための異方性導電フィルム１００Ｘの断面図である。
　以下、本発明の異方性導電フィルムを、図面を参照しつつ詳細に説明する。なお、各図中、同一符号は、同一又は同等の構成要素を表している。
＜異方性導電フィルムの全体構成＞
　図１Ａは、本発明の一実施例の異方性導電フィルム１０Ａについて、導電粒子１Ａ、１Ｂの配置を説明する平面図である。また、図１Ｂは、異方性導電フィルム１０Ａのｘ－ｘ断面図である。
　この異方性導電フィルム１０Ａは、２０％圧縮弾性率が８０００～２８０００Ｎ／ｍｍ2の高硬度導電粒子１Ａと、該高硬度導電粒子１Ａよりも２０％圧縮弾性率が低い低硬度導電粒子１Ｂの双方が絶縁性樹脂層２に分散している導電粒子分散層３から形成されている。高硬度導電粒子１Ａと低硬度導電粒子１Ｂを合わせた導電粒子全体の個数密度は６０００個／ｍｍ2以上であり、そのうち低硬度導電粒子１Ｂの個数密度が導電粒子全体の１０％以上を占めている。導電粒子全体として正方格子配列となっているが、各格子点に高硬度導電粒子１Ａと低硬度導電粒子１Ｂのいずれが位置するかについて規則性はない。
＜導電粒子＞
　導電粒子分散層３には、導電粒子として、高硬度導電粒子１Ａと低硬度導電粒子１Ｂの双方が存在する。このうち、高硬度導電粒子１Ａは、２０％圧縮弾性率が８０００～２８０００Ｎ／ｍｍ2である。
　ここで、２０％圧縮弾性率は、微小圧縮試験機（例えば、フィッシャー・インストルメンツ社製、フィッシャースコープＨ－１００）を用いて導電粒子に圧縮荷重を加えたときの導電粒子の圧縮変量を測定し、
２０％圧縮弾性率（Ｋ）(Ｎ／ｍｍ2 )=（３／２1/2）・Ｆ・Ｓ-3/2・Ｒ-1/2
により算出されるＫ値を使用することができる。
式中、
Ｆ：導電粒子が２０％圧縮変形したときの荷重値（Ｎ）
Ｓ：導電粒子が２０％圧縮変形したときの圧縮変位（ｍｍ）
Ｒ：導電粒子の半径（ｍｍ）
である。
　高硬度導電粒子の２０％圧縮弾性率を８０００Ｎ／ｍｍ2以上とすることにより、電子部品の端子表面に酸化皮膜が形成されていても高硬度導電粒子によってその酸化皮膜を突き破ることができ、また、２８０００Ｎ／ｍｍ2以下とすることにより、異方性導電接続時に必要な圧着力が過度に高まらず、従前の押圧治具を用いて異方性導電接続することが可能となる。
　高硬度導電粒子１Ａの粒子径は、導通抵抗の上昇を抑制し、且つショートの発生を抑制するために、好ましくは１μｍ以上３０μｍ以下、より好ましくは３μｍ以上１０μｍ未満である。絶縁性樹脂層に分散させる前の導電粒子の粒子径は、一般的な粒度分布測定装置により測定することができ、また、平均粒子径も粒度分布測定装置を用いて求めることができる。画像型でもレーザ型であってもよい。画像型の測定装置としては、一例として湿式フロー式粒子径・形状分析装置ＦＰＩＡ－３０００（マルバーン社）を挙げることができる。平均粒子径Ｄを測定するサンプル数（導電粒子個数）は１０００個以上が好ましい。異方性導電フィルムにおける導電粒子の粒子径は、ＳＥＭなどの電子顕微鏡観察から求めることができる。この場合、平均粒子径を測定するサンプル数を２００以上とすることが望ましい。
　なお、導電粒子として、その表面に絶縁性微粒子が付着しているものを使用する場合、本発明における導電粒子の粒子径は、表面の絶縁性微粒子を含まない粒子径を意味する。
　一方、低硬度導電粒子１Ｂは２０％圧縮弾性率が高硬度導電粒子よりも低く、好ましくは高硬度導電粒子の２０％圧縮弾性率の１０％以上７０％以下である。低硬度導電粒子１Ｂの２０％圧縮弾性率が低すぎると導通に寄与し難い状態となり、反対に高すぎると高硬度導電粒子との硬度差が不十分となり、本発明の効果を得られなくなる。
　低硬度導電粒子１Ｂの粒子径は、好ましくは１μｍ以上３０μｍ以下で、高硬度導電粒子の粒子径に対して８０％以上であれば実用上問題ないが、同等以上とすることが好ましい。低硬度導電粒子の粒子径を高硬度導電粒子の粒子径に対して同等以上とすることにより、高硬度導電粒子が端子表面の酸化皮膜に形成したクラックを利用して低硬度導電粒子が導通に寄与しやすくなる。
　上述の硬さ及び粒子径を有する高硬度導電粒子１Ａ及び低硬度導電粒子１Ｂは、公知の異方性導電フィルムに用いられている導電粒子の中から適宜選択することができる。例えばニッケル、コバルト、銀、銅、金、パラジウムなどの金属粒子、ハンダなどの合金粒子、金属被覆樹脂粒子、表面に絶縁性微粒子が付着している金属被覆樹脂粒子などが挙げられる。金属被覆樹脂粒子における金属層の厚みは５０ｎｍ～２５０ｎｍが好ましい。また、導電粒子は、表面に突起が設けられたものであってもよい。金属被覆樹脂粒子の場合は、特開２０１６－８９１５３号公報に挙げられているものを使用してもよい。
＜導電粒子の個数密度＞
　低硬度導電粒子１Ｂの個数密度は、導電粒子全体の１０％以上とし、接続する端子の種類や接続条件で適宜調整できる。一例として、好ましくは２０％以上８０％以下であり、より好ましくは３０％以上７０％以下である。導電粒子全体に対する低硬度導電粒子の個数密度が低すぎても高すぎても、高硬度導電粒子と低硬度導電粒子とを混合することによる本発明の効果を得られにくい。
　また、導電粒子全体の個数密度は、特に限定はされないが、一例として、導電粒子１Ａ、１Ｂ全体の平均粒子径Ｄが１０μｍ未満の場合には、好ましくは６０００個／ｍｍ2以上４２０００個／ｍｍ2以下である。平均粒子径が１０μｍ以上になる場合は、この範囲に限定はされない。一例として、２０個／ｍｍ2以上２０００個／ｍｍ2以下である。
　導電粒子１Ａ、１Ｂ全体の平均粒子径Ｄが１０μｍ未満になる場合に、導電粒子全体の個数密度が過度に高くなると、次式で算出される導電粒子の面積占有率も過度に高くなる。
　面積占有率
　＝［平面視における導電粒子の個数密度（個／ｍｍ2）］×［導電粒子１個の平面視面積の平均（ｍｍ2／個）］×１００
　面積占有率は、異方性導電フィルムを電子部品に熱圧着するために押圧治具に必要とされる推力の指標となる。この面積占有率を好ましくは３５％以下、より好ましくは０．３～３０％の範囲とすることにより、異方性導電フィルムを電子部品に熱圧着するために押圧治具に必要とされる推力を低く抑えることが可能となる。
　なお、導電粒子の個数密度は、金属顕微鏡などによる観測画像を用いて測定することができる。また、画像解析ソフト（例えば、ＷｉｎＲＯＯＦ、三谷商事株式会社等）により観察画像を計測して求めてもよい。導電粒子の個数密度を求める場合の測定領域は、１辺が１００μｍ以上の矩形領域を任意に複数箇所（好ましくは５箇所以上、より好ましくは１０箇所以上）設定し、測定領域の合計面積を２ｍｍ2以上とすることが好ましい。個々の領域の大きさや数は、個数密度の状態によって適宜調整すればよい。また、導電粒子１個の平面視面積の平均は、金属顕微鏡やＳＥＭなどの電子顕微鏡などによるフィルム面の観測画像の計測により求めることができる。画像解析ソフトを用いてもよい。観察方法や計測手法は、上述の方法に限定されるものではない。
　なお、導電粒子１Ａ、１Ｂ全体としての粒子間距離Ｌｇは、上述した導電粒子１Ａ、１Ｂの面積占有率が達成されるようにした上で、所定の個数密度及び粒子配置に応じて適宜設定する。
＜導電粒子の配置＞
　本発明の異方性導電フィルムにおいて、高硬度導電粒子１Ａ及び低硬度導電粒子１Ｂを含む導電粒子全体の、フィルムの平面視における配置は、規則的配置でもランダム配置でもよい。規則的配置の態様としては、図１Ａに示した正方格子の他、６方格子、斜方格子、長方格子等の格子配列を挙げることができる。また、導電粒子全体の粒子配置として、導電粒子１Ａ又は１Ｂが所定間隔で直線状に並んだ粒子列を所定の間隔で並列させてもよい。本発明において規則的な配置は、フィルムの長手方向で繰り返されるものであれば特に制限はない。
　一方、高硬度導電粒子１Ａ及び低硬度導電粒子１Ｂのそれぞれが規則的に配置されていてもよい。例えば、図２Ａ及び図２Ｂに示した異方性導電フィルム１０Ｂのように、低硬度導電粒子１Ｂの個数密度を導電粒子全体の５０％とし、高硬度導電粒子１Ａ及び低硬度導電粒子１Ｂのそれぞれを正方格子配列とすることができる。図２Ａでは、高硬度導電粒子１Ａ及び低硬度導電粒子１Ｂが交互に配置されているが、本発明はこのような厳密な配置も、そうではない配置も包含するものである。
　導電粒子全体としての粒子配列に格子軸又は配列軸がある場合に、その格子軸又は配列軸は異方性導電フィルム１０Ａの長手方向に対して平行でもよく、異方性導電フィルムの長手方向と交叉してもよく、接続する端子幅、端子ピッチなどに応じて定めることができる。例えば、ファインピッチ用の異方性導電フィルムとする場合、図１Ａに示したように導電粒子１Ａ、１Ｂの少なくとも一つの格子軸Ａを異方性導電フィルム１０Ａの長手方向に対して斜行させ、異方性導電フィルム１０Ａで接続する端子２０の長手方向と格子軸Ａとのなす角度θを１６°～７４°にすることが好ましい。
　また、フィルムの平面視において導電粒子１Ａ、１Ｂは互いに接触することなく存在し、フィルム厚方向にも導電粒子１Ａ、１Ｂが互いに重なることなく存在していることが好ましい。そのため、導電粒子全体に対し、導電粒子１Ａ、１Ｂ同士が互いに非接触で存在する個数割合は９５％以上、好ましくは９８％以上、より好ましくは９９．５％以上である。これは、規則的配置でもランダム配置でも同様である。後述するように、転写型を使用して導電粒子１Ａ、１Ｂを規則的に配置させると、導電粒子１Ａ、１Ｂ同士が互いに非接触で存在する割合を容易に制御することができるので好ましい。ランダム配置の場合は、絶縁性樹脂に導電粒子１Ａ、１Ｂを混練して異方性導電フィルムを作製することが容易なため、性能やコストとの兼ね合いで、転写型を利用する製造方法と、混練を利用する製造方法のどちらを選択してもよい。
　各導電粒子１Ａ、１Ｂは、互いに接触することなく存在する場合に、そのフィルム厚方向の位置が揃っていることが好ましい。例えば、高硬度導電粒子１Ａと低硬度導電粒子１Ｂの粒子径が等しい場合、図１Ｂに示したように、導電粒子１Ａ、１Ｂのフィルム厚方向の埋込量Ｌｂを揃えることができる。即ち、絶縁性樹脂層２の一方の界面からの距離を揃えることができるので、端子における導電粒子の捕捉性が安定し易い。
　また、高硬度導電粒子１Ａと低硬度導電粒子１Ｂの粒子径が異なる場合には、導電粒子１Ａ、１Ｂの絶縁性樹脂層２への埋め込みにより該絶縁性樹脂層２の表面から導電粒子１Ａ、１Ｂまでの距離が同じになっていると、上記と同様の理由から端子における導電粒子の捕捉性が安定し易い。一方、図３に示したように、導電粒子１Ａ、１Ｂを絶縁性樹脂層２から露出させる場合には、高硬度導電粒子１Ａ及び低硬度導電粒子１Ｂの各導電粒子が絶縁性樹脂層２から露出している頂部のフィルム厚方向の位置を揃えることもできる。なお、絶縁性樹脂層２の層厚Ｌａと導電粒子１Ａ、１Ｂの平均粒子径Ｄとの比（Ｌａ／Ｄ）の関係については後述する。
　高硬度導電粒子１Ａと低硬度導電粒子１Ｂの粒子径が等しい場合も異なる場合も、導電粒子１Ａ、１Ｂが絶縁性樹脂層２から露出していると、接続時にかかる圧力が導電粒子１Ａ、１Ｂに伝わり易くなる。金属被覆樹脂粒子の場合を例に詳細に述べると、後述する凹み２ｂ、２ｃの作用と同様に、導電粒子１Ａ、１Ｂが絶縁性樹脂層２から露出していると、異方性導電接続時に押圧治具による金属被覆樹脂粒子の押し込みによって生じる、該金属被覆樹脂粒子の変形に対する絶縁性樹脂層２の抵抗が低減されるため、接続後の圧痕の状態が均一になり易い。これにより、接続後の状態が確認し易くなる。
　ここで、埋込量Ｌｂは、導電粒子１Ａ、１Ｂが埋め込まれている絶縁性樹脂層２の表面（絶縁性樹脂層２の表裏の面のうち、導電粒子１Ａ、１Ｂが露出している側の表面、又は導電粒子１Ａ、１Ｂが絶縁性樹脂層２に完全に埋め込まれている場合には、導電粒子１Ａ、１Ｂとの距離が近い表面）であって、隣接する導電粒子間の中央部における接平面２ｐと、導電粒子１Ａ、１Ｂの最深部との距離をいう。導電粒子１Ａ、１Ｂの平均粒子径Ｄに対する埋込量Lｂの割合を埋込率（Ｌｂ／Ｄ）とした場合に、埋込率は３０％以上１０５％以下が好ましい。
　埋込率（Ｌｂ／Ｄ）を３０％以上６０％未満とすると導電粒子を保持する比較的高粘度の樹脂から粒子が露出している比率が高くなることから、より低圧実装が容易になる。６０％以上とすることにより、導電粒子１Ａ、１Ｂを絶縁性樹脂層２によって所定の粒子分散状態あるいは所定の配置に維持し易くなる。また、１０５％以下とすることにより、異方性導電接続時に端子間の導電粒子を無用に流動させるように作用する絶縁性樹脂層の樹脂量を低減させることができる。尚、導電粒子１Ａ、１Ｂは絶縁性樹脂層２を貫通していてもよく、その場合の埋込率（Ｌｂ／Ｄ）は１００％となる。
　なお、本発明において、埋込率（Ｌｂ／Ｄ）の数値は、異方性導電フィルムに含まれる全導電粒子数の８０％以上、好ましくは９０％以上、より好ましくは９６％以上が、当該埋込率（Ｌｂ／Ｄ）の数値になっていることをいう。したがって、埋込率が３０％以上１０５％以下とは、異方性導電フィルムに含まれる全導電粒子数の８０％以上、好ましくは９０％以上、より好ましくは９６％以上の埋込率が３０％以上１０５％以下であることをいう。このように全導電粒子の埋込率（Ｌｂ／Ｄ）が揃っていることにより、押圧の加重が導電粒子に均一にかかるので、端子における導電粒子の捕捉状態が良好になり、導通の信頼性が期待できる。より精度を上げるため、２００個以上の導電粒子を計測して求めてもよい。
　また、埋込率（Ｌｂ／Ｄ）の計測は、面視野画像において焦点調整することにより、ある程度の個数について一括して求めることができる。もしくは埋込率（Ｌｂ／Ｄ）の計測にレーザ式判別変位センサ（（株）キーエンス製など）を用いてもよい。
＜絶縁性樹脂層＞
（絶縁性樹脂層の粘度）
　本発明の異方性導電フィルムにおいて、絶縁性樹脂層２の最低溶融粘度は、特に制限はなく、異方性導電フィルムの使用対象や、異方性導電フィルムの製造方法等に応じて適宜定めることができる。例えば、後述の凹み２ｂ（図４）、２ｃ（図５）を形成できる限り、異方性導電フィルムの製造方法によっては１０００Ｐａ・ｓ程度とすることもできる。一方、異方性導電フィルムの製造方法として、導電粒子を絶縁性樹脂層の表面に所定の配置で保持させ、その導電粒子を絶縁性樹脂層に押し込む方法を行うとき、絶縁性樹脂層がフィルム成形を可能とする点から絶縁性樹脂層の最低溶融粘度を１１００Ｐａ・ｓ以上とすることが好ましい。
　また、後述の異方性導電フィルムの製造方法で説明するように、図４に示すように絶縁性樹脂層２に押し込んだ導電粒子１Ａ、１Ｂの露出部分の周りに凹み２ｂを形成したり、図５に示すように絶縁性樹脂層２に押し込んだ導電粒子１Ａ、１Ｂの直上に凹み２ｃを形成したりする点から、好ましくは１５００Ｐａ・ｓ以上、より好ましくは２０００Ｐａ・ｓ以上、さらに好ましくは３０００～１５０００Ｐａ・ｓ、さらにより好ましくは３０００～１００００Ｐａ・ｓである。この最低溶融粘度は、一例として回転式レオメータ（ＴＡ ｉｎｓｔｒｕｍｅｎｔｓ社製）を用い、測定圧力５ｇで一定に保持し、直径８ｍｍの測定プレートを使用し求めることができ、より具体的には、温度範囲３０～２００℃において、昇温速度１０℃／分、測定周波数１０Ｈｚ、前記測定プレートに対する荷重変動５ｇとすることにより求めることができる。
　絶縁性樹脂層２の最低溶融粘度を１５００Ｐａ・ｓ以上の高粘度とすることにより、異方性導電フィルムの物品への圧着に導電粒子の無用な移動を抑制でき、特に、異方性導電接続時に端子間で挟持されるべき導電粒子が樹脂流動により流されてしまうことを防止できる。
　また、絶縁性樹脂層２に導電粒子１Ａ、１Ｂを押し込むことにより異方性導電フィルム１０Ａの導電粒子分散層３を形成する場合において、導電粒子１Ａ、１Ｂを押し込むときの絶縁性樹脂層２は、導電粒子１Ａ、１Ｂが絶縁性樹脂層２から露出するように導電粒子１Ａ、１Ｂを絶縁性樹脂層２に押し込んだときに、絶縁性樹脂層２が塑性変形して導電粒子１Ａ、１Ｂの周囲の絶縁性樹脂層２に凹み２ｂ（図４）が形成されるような高粘度な粘性体とするか、あるいは、導電粒子１Ａ、１Ｂが絶縁性樹脂層２から露出することなく絶縁性樹脂層２に埋まるように導電粒子１Ａ、１Ｂを押し込んだときに、導電粒子１Ａ、１Ｂの直上の絶縁性樹脂層２の表面に凹み２ｃ（図５）が形成されるような高粘度な粘性体とする。そのため、絶縁性樹脂層２の６０℃における粘度は、下限は好ましくは３０００Ｐａ・ｓ以上、より好ましくは４０００Ｐａ・ｓ以上、さらに好ましくは４５００Ｐａ・ｓ以上であり、上限は、好ましくは２００００Ｐａ・ｓ以下、より好ましくは１５０００Ｐａ・ｓ以下、さらに好ましくは１００００Ｐａ・ｓ以下である。この測定は最低溶融粘度と同様の測定方法で行い、温度が６０℃の値を抽出して求めることができる。
　絶縁性樹脂層２に導電粒子１Ａ、１Ｂを押し込むときの該絶縁性樹脂層２の具体的な粘度は、形成する凹み２ｂ、２ｃの形状や深さなどに応じて、下限は好ましくは３０００Ｐａ・ｓ以上、より好ましくは４０００Ｐａ・ｓ以上、さらに好ましくは４５００Ｐａ・ｓ以上であり、上限は、好ましくは２００００Ｐａ・ｓ以下、より好ましくは１５０００Ｐａ・ｓ以下、さらに好ましくは１００００Ｐａ・ｓ以下である。また、このような粘度を好ましくは４０～８０℃、より好ましくは５０～６０℃で得られるようにする。
　上述したように、絶縁性樹脂層２から露出している導電粒子１Ａ、１Ｂの周囲に凹み２ｂ（図４）が形成されていることにより、異方性導電フィルムの物品への圧着時に生じる導電粒子１Ａ、１Ｂの扁平化に対して絶縁性樹脂から受ける抵抗が、凹み２ｂが無い場合に比して低減する。このため、異方性導電接続時に端子で導電粒子が挟持され易くなることで導通性能が向上し、また捕捉性が向上する。
　また、絶縁性樹脂層２から露出することなく埋まっている導電粒子１Ａ、１Ｂの直上の絶縁性樹脂層２の表面に凹み２ｃ（図５）が形成されていることにより、凹み２ｃが無い場合に比して異方性導電フィルムの物品への圧着時の圧力が導電粒子１Ａ、１Ｂに集中し易くなる。このため、異方性導電接続時に端子で導電粒子が挟持され易くなることで捕捉性が向上し、導通性能が向上する。
＜凹みに代わる“傾斜”又は“起伏”＞
　図４、５に示すような異方性導電フィルムの 「凹み」２ｂ、２ｃは、「傾斜」または「起伏」という観点から説明することもできる。以下に、図面（図８～１５）を参照しながら説明する。
　異方性導電フィルム１００Ａは導電粒子分散層３から構成されている（図８）。導電粒子分散層３では、絶縁性樹脂層２の片面に高硬度導電粒子１Ａ、低硬度導電粒子１Ｂが露出した状態で規則的に分散している。フィルムの平面視にて導電粒子１Ａ、１Ｂは互いに接触しておらず、フィルム厚方向にも導電粒子１Ａ、１Ｂが互いに重なることなく規則的に分散し、導電粒子１Ａ、１Ｂのフィルム厚方向の位置が揃った単層の導電粒子層を構成している。
　個々の導電粒子１Ａ、１Ｂの周囲の絶縁性樹脂層２の表面２ａには、隣接する導電粒子間の中央部における絶縁性樹脂層２の接平面２ｐに対して傾斜２ｂが形成されている。なお後述するように、本発明の異方性導電フィルムでは、絶縁性樹脂層２に埋め込まれた導電粒子１Ａ、１Ｂの直上の絶縁性樹脂層の表面に起伏２ｃが形成されていてもよい（図１１、図１３）。
　本発明において、「傾斜」とは、導電粒子１Ａ、１Ｂの近傍で絶縁性樹脂層の表面の平坦性が損なわれ、前記接平面２ｐに対して樹脂層の一部が欠けて樹脂量が低減している状態を意味する。換言すれば、傾斜では、導電粒子の周りの絶縁性樹脂層の表面が接平面に対して欠けていることになる。一方、「起伏」とは、導電粒子の直上の絶縁性樹脂層の表面にうねりがあり、うねりのように高低差がある部分が存在することで樹脂が低減している状態を意味する。換言すれば、導電粒子直上の絶縁性樹脂層の樹脂量が、導電粒子直上の絶縁性樹脂層の表面が接平面にあるとしたときに比して少なくなる。これらは、導電粒子の直上に相当する部位と導電粒子間の平坦な表面部分（図１１、図１３の２ｆ）とを対比して認識することができる。なお、起伏の開始点が傾斜として存在する場合もある。
　上述したように、絶縁性樹脂層２から露出している導電粒子１Ａ、１Ｂの周囲に傾斜２ｂ（図８）が形成されていることにより、異方性導電接続時に導電粒子１Ａ、１Ｂが端子間で挟持される際に生じる導電粒子１Ａ、１Ｂの扁平化に対して絶縁性樹脂層から受ける抵抗が、傾斜２ｂが無い場合に比して低減するため、端子において導電粒子が挟持され易くなることで導通性能が向上し、また捕捉性が向上する。この傾斜は、導電粒子の外形に沿っていることが好ましい。接続における効果がより発現しやすくなる以外に、導電粒子を認識し易くなることで、異方性導電フィルムの製造における検査などが行い易くなるからである。また、この傾斜および起伏は絶縁性樹脂層にヒートプレスするなどにより、その一部が消失してしまう場合があるが、本発明はこれを包含する。この場合、導電粒子は絶縁性樹脂層の表面に１点で露出する場合がある。なお、異方性導電フィルムは、接続する電子部品が多様であり、これらに合わせてチューニングする以上、種々の要件を満たせるように設計の自由度が高いことが望まれるので、傾斜もしくは起伏を低減させても部分的に消失させても用いることができる。
　また、絶縁性樹脂層２から露出することなく埋まっている導電粒子１Ａ、１Ｂの直上の絶縁性樹脂層２の表面に起伏２ｃ（図１１、図１３）が形成されていることにより、傾斜の場合と同様に、異方性導電接続時に端子からの押圧力が導電粒子にかかりやすくなる。また、起伏があることにより樹脂が平坦に堆積している場合よりも導電粒子の直上の樹脂量が低減しているため、接続時の導電粒子直上の樹脂の排除が生じやすくなり、端子と導電粒子とが接触し易くなることから、端子における導電粒子の捕捉性が向上し、導通信頼性が向上する。
（縁性樹脂層の厚さ方向における導電粒子の位置）
　「傾斜」もしくは「起伏」という観点を考慮した場合の絶縁性樹脂層２の厚さ方向における導電粒子１Ａ、１Ｂの位置は、前述と同様に、導電粒子１Ａ、１Ｂが絶縁性樹脂層２から露出していてもよく、露出することなく、絶縁性樹脂層２内に埋め込まれていても良いが、隣接する導電粒子間の中央部における接平面２ｐからの導電粒子の最深部の距離（以下、埋込量という）Ｌｂと、導電粒子の平均粒子径Ｄとの比（Ｌｂ／Ｄ）（以下、埋込率という）が３０％以上１０５％以下であることが好ましい。
　埋込率（Ｌｂ／Ｄ）を３０％以上とすることにより、導電粒子１Ａ、１Ｂを絶縁性樹脂層２によって所定の粒子分散状態あるいは所定の配置に維持し、また、１０５％以下とすることにより、異方性導電接続時に端子間の導電粒子を無用に流動させるように作用する絶縁性樹脂層の樹脂量を低減させることができる。
　なお、埋込率（Ｌｂ／Ｄ）の数値は、異方性導電フィルムに含まれる全導電粒子数の８０％以上、好ましくは９０％以上、より好ましくは９６％以上が、当該埋込率（Ｌｂ／Ｄ）の数値になっていることをいう。したがって、埋込率３０％以上１０５％以下とは、異方性導電フィルムに含まれる全導電粒子数の８０％以上、好ましくは９０％以上、より好ましくは９６％以上の埋込率が３０％以上１０５％以下であることをいう。このように全導電粒子の埋込率（Ｌｂ／Ｄ）が揃っていることにより、押圧の加重が導電粒子に均一にかかるので、端子における導電粒子の捕捉状態が良好になり、導通の信頼性が向上する。
　埋込率（Ｌｂ／Ｄ）は、異方性導電フィルムから面積３０ｍｍ２以上の領域を任意に１０箇所以上抜き取り、そのフィルム断面の一部をＳＥＭ画像で観察し、合計５０個以上の導電粒子を計測することにより求めることができる。より精度を上げるため、２００個以上の導電粒子を計測して求めてもよい。
　また、埋込率（Ｌｂ／Ｄ）の計測は、面視野画像において焦点調整することにより、ある程度の個数について一括して求めることができる。もしくは埋込率（Ｌｂ／Ｄ）の計測にレーザ式判別変位センサ（（株）キーエンス製など）を用いてもよい。
（埋込率３０％以上６０％未満の態様）
　埋込率（Ｌｂ/Ｄ）３０％以上６０％未満の導電粒子１Ａ、１Ｂのより具体的な埋込態様としては、まず、図８に示した異方性導電フィルム１００Ａのように、導電粒子１Ａ、１Ｂが絶縁性樹脂層２から露出するように埋込率３０％以上６０％未満で埋め込まれた態様をあげることができる。この異方性導電フィルム１００Ａは、絶縁性樹脂層２の表面のうち該絶縁性樹脂層２から露出している導電粒子１Ａ、１Ｂと接している部分及びその近傍が、隣接する導電粒子間の中央部の絶縁性樹脂層の表面２ａにおける接平面２ｐに対して導電粒子の外形に概ね沿った稜線となる傾斜２ｂを有している。
　このような傾斜２ｂもしくは後述する起伏２ｃは、異方性導電フィルム１００Ａを、絶縁性樹脂層２に導電粒子１Ａ、１Ｂを押し込むことにより製造する場合に、導電粒子１Ａ、１Ｂの押し込みを、４０～８０℃で３０００～２００００Ｐａ・ｓ、より好ましくは４５００～１５０００Ｐａ・ｓの粘度で行うことにより形成することができる。
（埋込率６０％以上１００％未満の態様）
　埋込率（Ｌｂ／Ｄ）６０％以上１００％未満の導電粒子１Ａ、１Ｂのより具体的な埋込態様としては、まず、図８に示した異方性導電フィルム１００Ａのように、導電粒子１Ａ、１Ｂが絶縁性樹脂層２から露出するように埋込率６０％以上１００％未満で埋め込まれた態様をあげることができる。この異方性導電フィルム１００Ａは、絶縁性樹脂層２の表面のうち該絶縁性樹脂層２から露出している導電粒子１Ａ、１Ｂと接している部分及びその近傍が、隣接する導電粒子間の中央部の絶縁性樹脂層の表面２ａにおける接平面２ｐに対して導電粒子の外形に概ね沿った稜線となる傾斜２ｂを有している。
　このような傾斜２ｂもしくは後述する起伏２ｃは、異方性導電フィルム１００Ａを、絶縁性樹脂層２に導電粒子１Ａ、１Ｂを押し込むことにより製造する場合に、導電粒子１Ａ、１Ｂの押し込み時の粘度を、下限は、好ましくは３０００Ｐａ・ｓ以上、より好ましくは４０００Ｐａ・ｓ以上、さらに好ましくは４５００Ｐａ・ｓ以上とし、上限は、好ましくは２００００Ｐａ・ｓ以下、より好ましくは１５０００Ｐａ・ｓ以下、更に好ましくは１００００Ｐａ・ｓ以下とする。また、このような粘度を好ましくは４０～８０℃、より好ましくは５０～６０℃で得られるようにする。なお、絶縁性樹脂層をヒートプレスすることなどにより傾斜２ｂや起伏２ｃの一部が消失してもよく、傾斜２ｂが起伏２ｃに変化してもよく、また、起伏２ｃを有する導電粒子が、その頂部の１点で絶縁性樹脂層２に露出してもよい。
（埋込率１００％の態様）
　次に、本発明の異方性導電フィルムのうち、埋込率（Ｌｂ／Ｄ）１００％の態様としては、図９に示す異方性導電フィルム１００Ｂのように、導電粒子１Ａ、１Ｂの周りに図８に示した異方性導電フィルム１００Ａと同様の導電粒子の外形に概ね沿った稜線となる傾斜２ｂを有し、絶縁性樹脂層２から露出している導電粒子１Ａ、１Ｂの露出径Ｌｃが導電粒子の平均粒子径Ｄよりも小さいもの、図１０Ａに示す異方性導電フィルム１００Ｃのように、導電粒子１Ａ、１Ｂの露出部分の周りの傾斜２ｂが導電粒子１Ａ、１Ｂの近傍で急激に現れ、導電粒子１Ａ、１Ｂの露出径Ｌｃと導電粒子の平均粒子径Ｄとが略等しいもの、図１１に示す異方性導電フィルム１００Ｄのように、絶縁性樹脂層２の表面に浅い起伏２ｃがあり、導電粒子１Ａ、１Ｂがその頂部１ａの１点で絶縁性樹脂層２から露出しているものをあげることができる。
　なお、導電粒子の露出部分の周りの絶縁性樹脂層２の傾斜２ｂや、導電粒子の直上の絶縁性樹脂層の起伏２ｃに隣接して微小な突出部分２ｑが形成されていてもよい。この一例を図１０Ｂに示す。
　これらの異方性導電フィルム１００Ｂ（図９）、１００Ｃ（図１０Ａ）、１００Ｄ（図１１）は埋込率１００％であるため、導電粒子１Ａ、１Ｂの頂部１ａと絶縁性樹脂層２の表面２ａとが面一に揃っている。導電粒子１Ａ、１Ｂの頂部１ａと絶縁性樹脂層２の表面２ａとが面一に揃っていると、図８に示したように導電粒子１Ａ、１Ｂが絶縁性樹脂層２から突出している場合に比して、異方性導電接続時に個々の導電粒子の周辺にてフィルム厚み方向の樹脂量が不均一になりにくく、樹脂流動による導電粒子の移動を低減できるという効果がある。なお、埋込率が厳密に１００％でなくても、絶縁性樹脂層２に埋め込まれた導電粒子１Ａ、１Ｂの頂部１ａと絶縁性樹脂層２の表面２ａとが面一となる程度に揃っているとこの効果を得ることができる。言い換えると、埋込率（Ｌｂ/Ｄ）が概略８０～１０５％、特に、９０～１００％の場合には、絶縁性樹脂層２に埋め込まれた導電粒子１Ａ、１Ｂの頂部１ａと絶縁性樹脂層２の表面２ａとは面一であるといえ、樹脂流動による導電粒子の移動を低減させることができる。
　これらの異方性導電フィルム１００Ｂ（図９）、１００Ｃ（図１０Ａ）、１００Ｄ（図１１）の中でも、１００Ｄは導電粒子１Ａ、１Ｂの周りの樹脂量が不均一になりにくいので樹脂流動による導電粒子の移動を解消でき、また頂部１ａの１点であっても絶縁性樹脂層２から導電粒子１Ａ、１Ｂが露出しているので、端子における導電粒子１Ａ、１Ｂの捕捉性も良く、導電粒子のわずかな移動も起こりにくいという効果が期待できる。したがって、この態様は、特にファインピッチやバンプ間スペースが狭い場合に有効である。
　なお、傾斜２ｂ、起伏２ｃの形状や深さが異なる異方性導電フィルム１００Ｂ（図９）、１００Ｃ（図１０Ａ）、１００Ｄ（図１１）は、後述するように、導電粒子１Ａ、１Ｂの押し込み時の絶縁性樹脂層２の粘度等を変えることで製造することができる。
（埋込率１００％超の態様）
　本発明の異方性導電フィルムのうち、埋込率１００％を超える場合、図１２に示す異方性導電フィルム１００Ｅのように導電粒子１Ａ、１Ｂが露出し、その露出部分の周りの絶縁性樹脂層２の接平面２ｐに対する傾斜２ｂもしくは導電粒子１Ａ、１Ｂの直上の絶縁性樹脂層２の接平面２ｐに対する起伏２ｃ（図１３）があるものをあげることができる。
　なお、導電粒子１Ａ、１Ｂの露出部分の周りの絶縁性樹脂層２に傾斜２ｂを有する異方性導電フィルム１００Ｅ（図１２）と導電粒子１Ａ、１Ｂの直上の絶縁性樹脂層２に起伏２ｃを有する異方性導電フィルム１００Ｆ（図１３）は、それらを製造する際の導電粒子１Ａ、１Ｂの押し込み時の絶縁性樹脂層２の粘度等を変えることで製造することができる。
　なお、図１２に示す異方性導電フィルム１００Ｅを異方性導電接続に使用すると、導電粒子１Ａ、１Ｂが端子から直接押圧されるので、端子における導電粒子の捕捉性が向上する。また、図１３に示す異方性導電フィルム１００Ｆを異方性導電接続に使用すると、導電粒子１Ａ、１Ｂが端子を直接押圧せず、絶縁性樹脂層２を介して押圧することになるが、押圧方向に存在する樹脂量が図１５の状態（即ち、導電粒子１Ａ、１Ｂが埋込率１００％を超えて埋め込まれ、導電粒子１Ａ、１Ｂが絶縁性樹脂層２から露出しておらず、かつ絶縁性樹脂層２の表面が平坦である状態）に比べて少ないため、導電粒子に押圧力がかかりやすくなり、且つ異方性導電接続時に端子間の導電粒子１Ａ、１Ｂが樹脂流動により無用に移動することが妨げられる。
　上述した導電粒子の露出部分の周りの絶縁性樹脂層２の傾斜２ｂ（図８、図９、図１０Ａ、図１２）や、導電粒子の直上の絶縁性樹脂層の起伏２ｃ（図１１、図１３）の効果を得易くする点から傾斜２ｂの最大深さＬｅと導電粒子１Ａ、１Ｂの平均粒子径Ｄとの比（Ｌｅ／Ｄ）は、好ましくは５０％未満、より好ましくは３０％未満、さらに好ましくは２０～２５％であり、傾斜２ｂや起伏２ｃの最大径Ｌｄと導電粒子１Ａ、１Ｂの平均粒子径Ｄとの比（Ｌｄ／Ｄ）は、好ましくは１００％以上、より好ましくは１００～１５０％であり、起伏２ｃの最大深さＬｆと導電粒子１Ａ、１Ｂの平均粒子径Ｄとの比（Ｌｆ／Ｄ）は、０より大きく、好ましくは１０％未満、より好ましくは５％以下である。
　なお、傾斜２ｂや起伏２ｃにおける導電粒子１Ａ、１Ｂの露出（直上）部分の径Ｌｃは、導電粒子１Ａ、１Ｂの平均粒子径Ｄ以下とすることができ、好ましくは平均粒子径Ｄの１０～９０％である。導電粒子１Ａ、１Ｂの頂部の１点で露出するようにしてもよく、導電粒子１Ａ、１Ｂが絶縁性樹脂層２内に完全に埋まり、径Ｌｃがゼロとなるようにしてもよい。
　なお、図１４に示すように、埋込率（Ｌｂ／Ｄ）が６０％未満の異方性導電フィルム１００Ｇでは、絶縁性樹脂層２上を導電粒子１Ａ、１Ｂが転がりやすくなるため、異方性導電接続時の捕捉率を向上させる点からは、埋込率（Ｌｂ／Ｄ）を６０％以上とすることが好ましい。
　また、埋込率が１００％を超える態様（Ｌｂ／Ｄ）において、図１５に示す比較例の異方性導電フィルム１００Ｘのように絶縁性樹脂層２の表面が平坦な場合は導電粒子１Ａ、１Ｂと端子との間に介在する樹脂量が過度に多くなる。また、導電粒子１Ａ、１Ｂが直接端子に接触して端子を押圧することなく、絶縁性樹脂層を介して端子を押圧するので、これによっても導電粒子が樹脂流動によって流され易い。
　このような本発明において、絶縁性樹脂層２の表面の傾斜２ｂ、起伏２ｃの存在は、異方性導電フィルムの断面を走査型電子顕微鏡で観察することにより確認することができ、面視野観察においても確認できる。光学顕微鏡、金属顕微鏡でも傾斜２ｂ、起伏２ｃの観察は可能である。また、傾斜２ｂ、起伏２ｃの大きさは画像観察時の焦点調整などで確認することもできる。上述のようにヒートプレスにより傾斜もしくは起伏を減少させた後であっても、同様である。痕跡が残る場合があるからである。
（絶縁性樹脂層の組成）
　絶縁性樹脂層２は、硬化性樹脂組成物から形成することが好ましく、例えば、熱重合性化合物と熱重合開始剤とを含有する熱重合性組成物から形成することができる。熱重合性組成物には必要に応じて光重合開始剤を含有させてもよい。
　熱重合開始剤と光重合開始剤を併用する場合に、熱重合性化合物としても光重合性化合物としても機能するものを使用してもよく、熱重合性化合物とは別に光重合性化合物を含有させてもよい。好ましくは、熱重合性化合物とは別に光重合性化合物を含有させる。例えば、熱重合開始剤として熱カチオン系重合開始剤、熱重合性化合物としてエポキシ化合物を使用し、光重合開始剤として光ラジカル重合開始剤、光重合性化合物としてアクリレート化合物を使用する。
　光重合開始剤として、波長の異なる光に反応する複数種類を含有させてもよい。これにより、異方性導電フィルムの製造時における、絶縁性樹脂層を構成する樹脂の光硬化と、異方性導電接続時に電子部品同士を接着するための樹脂の光硬化とで使用する波長を使い分けることができる。
　異方性導電フィルムの製造時の光硬化では、絶縁性樹脂層に含まれる光重合性化合物の全部又は一部を光硬化させることができる。この光硬化により、絶縁性樹脂層２における導電粒子１Ａ、１Ｂの配置が保持乃至固定化され、ショートの抑制と捕捉の向上が見込まれる。また、この光硬化により、異方性導電フィルムの製造工程における絶縁性樹脂層の粘度を適宜調整してもよい。特にこの光硬化は、絶縁性樹脂層２の層厚Ｌａと導電粒子１Ａ、１Ｂの平均粒子径Ｄとの比（Ｌａ／Ｄ）が０．６未満である場合に行うことが好ましい。導電粒子径に対して絶縁性樹脂層２の層厚が薄い場合にも絶縁性樹脂層２で導電粒子の配置の保持乃至固定化をより確実に行うと共に、絶縁性樹脂層２の粘度調整を行い、異方性導電フィルムを用いた電子部品同士の接続において歩留まりの低下を抑制するためである。
　絶縁性樹脂層における光重合性化合物の配合量は３０質量％以下が好ましく、１０質量％以下がより好ましく、２質量％未満がより好ましい。光重合性化合物が多すぎると接続時の押し込みにかかる推力が増加するためである。
　熱重合性組成物の例としては、（メタ）アクリレート化合物と熱ラジカル重合開始剤とを含む熱ラジカル重合性アクリレート系組成物、エポキシ化合物と熱カチオン重合開始剤とを含む熱カチオン重合性エポキシ系組成物等が挙げられる。熱カチオン重合開始剤を含む熱カチオン重合性エポキシ系組成物に代えて、熱アニオン重合開始剤を含む熱アニオン重合性エポキシ系組成物を使用してもよい。また、特に支障を来さなければ、複数種の重合性化合物を併用してもよい。併用例としては、カチオン重合性化合物とラジカル重合性化合物の併用などが挙げられる。
　ここで、（メタ）アクリレート化合物としては、従来公知の熱重合型（メタ）アクリレートモノマーを使用することができる。例えば、単官能（メタ）アクリレート系モノマー、二官能以上の多官能（メタ）アクリレート系モノマーを使用することができる。
　熱ラジカル重合開始剤としては、例えば、有機過酸化物、アゾ系化合物等を挙げることができる。特に、気泡の原因となる窒素を発生しない有機過酸化物を好ましく使用することができる。
　熱ラジカル重合開始剤の使用量は、少なすぎると硬化不良となり、多すぎると製品ライフの低下となるので、（メタ）アクリレート化合物１００質量部に対し、好ましくは２～６０質量部、より好ましくは５～４０質量部である。
　エポキシ化合物としては、ビスフェノールＡ型エポキシ樹脂、ビスフェノールＦ型エポキシ樹脂、ノボラック型エポキシ樹脂、それらの変性エポキシ樹脂、脂環式エポキシ樹脂などを挙げることができ、これらの２種以上を併用することができる。また、エポキシ化合物に加えてオキセタン化合物を併用してもよい。
　熱カチオン重合開始剤としては、エポキシ化合物の熱カチオン重合開始剤として公知のものを採用することができ、例えば、熱により酸を発生するヨードニウム塩、スルホニウム塩、ホスホニウム塩、フェロセン類等を用いることができ、特に、温度に対して良好な潜在性を示す芳香族スルホニウム塩を好ましく使用することができる。
　熱カチオン重合開始剤の使用量は、少なすぎても硬化不良となる傾向があり、多すぎても製品ライフが低下する傾向があるので、エポキシ化合物１００質量部に対し、好ましくは２～６０質量部、より好ましくは５～４０質量部である。
　熱重合性組成物は、膜形成樹脂やシランカップリング剤を含有することが好ましい。膜形成樹脂としては、フェノキシ樹脂、エポキシ樹脂、不飽和ポリエステル樹脂、飽和ポリエステル樹脂、ウレタン樹脂、ブタジエン樹脂、ポリイミド樹脂、ポリアミド樹脂、ポリオレフィン樹脂等を挙げることができ、これらの２種以上を併用することができる。これらの中でも、成膜性、加工性、接続信頼性の観点から、フェノキシ樹脂を好ましく使用することができる。重量平均分子量は１００００以上であることが好ましい。また、シランカップリング剤としては、エポキシ系シランカップリング剤、アクリル系シランカップリング剤等を挙げることができる。これらのシランカップリング剤は、主としてアルコキシシラン誘導体である。
　熱重合性組成物には、溶融粘度調整のために、上述の導電粒子１Ａ、１Ｂとは別に絶縁性フィラーを含有させてもよい。これはシリカ粉やアルミナ粉などが挙げられる。絶縁性フィラー粒径２０～１０００ｎｍの微小なフィラーが好ましく、また、配合量はエポキシ化合物等の熱重合性化合物（光重合性化合物）１００質量部に対して５～５０質量部とすることが好ましい。
　本発明の異方性導電フィルムには、上述の絶縁性のフィラーとは別に充填剤、軟化剤、促進剤、老化防止剤、着色剤（顔料、染料）、有機溶剤、イオンキャッチャー剤などを含有させてもよい。
（絶縁性樹脂層の層厚）
　本発明の異方性導電フィルムでは、絶縁性樹脂層２の層厚Ｌａと導電粒子１Ａ、１Ｂの平均粒子径Ｄとの比（Ｌａ／Ｄ）が後述の理由から下限を０．３以上とすることができ、上限を１０以下することができる。従って、その比は０．３～１０が好ましく、０．６～８がより好ましく、０．６～６が更に好ましい。ここで、導電粒子１Ａ、１Ｂの平均粒子径Ｄは、その平均粒子径を意味する。絶縁性樹脂層２の層厚Ｌａが大き過ぎると異方性導電接続時に導電粒子１Ａ、１Ｂが樹脂流動により位置ずれしやすくなり、端子における導電粒子１Ａ、１Ｂの捕捉性が低下する。この傾向はこの比（Ｌａ／Ｄ）が１０を超えると顕著であるため、８以下がより好ましく、６以下が更に好ましい。反対に絶縁性樹脂層２の層厚Ｌａが小さすぎてこの比（Ｌａ／Ｄ）が０．３未満となると、導電粒子１Ａ、１Ｂを絶縁性樹脂層２によって所定の粒子分散状態あるいは所定の配置に維持することが困難となるので比（Ｌａ／Ｄ）は０．３以上が好ましく、絶縁性樹脂層２によって所定の粒子分散状態あるいは所定の配置を確実に維持する点から０．６以上がより好ましい。また、接続する端子が高密度ＣＯＧの場合、絶縁性樹脂層２の層厚Ｌａと導電粒子１Ａ、１Ｂの平均粒子径Ｄとの比（Ｌａ／Ｄ）は、好ましくは０．８～２である。
　一方、平均粒子径Ｄが１０μｍ以上の場合には、Ｌａ／Ｄは、上限に関しては、３．５以下、好ましくは２．５以下、より好ましくは２以下とし、下限に関しては０．８以上、好ましくは１以上、より好ましくは１．３より大きくする。
　平均粒子径Ｄの大きさに関わらず、絶縁性樹脂層２の層厚Ｌａが大き過ぎてこの比が過度に大きくなると、異方性導電接続時に導電粒子１Ａ、１Ｂが端子に押し付けられにくくなると共に、樹脂流動により導電粒子が流されやすくなる。そのため導電粒子が位置ずれしやすくなり、端子における導電粒子の捕捉性が低下する。また、導電粒子を端子に押し付けるために押圧治具に必要とされる推力も増大し、低圧実装の妨げになる。反対に絶縁性樹脂層２の層厚Ｌａが小さすぎてこの比が過度に小さくなると、導電粒子１Ａ、１Ｂを絶縁性樹脂層２によって所定の配置に維持することが困難となる。
＜変形態様＞
　本発明の異方性導電フィルムとしては、導電粒子分散層３に、絶縁性樹脂層２を構成する樹脂よりも最低溶融粘度が低い第２の絶縁性樹脂層４を積層することができる（図６、図７）。この第２の絶縁性樹脂層４は、異方性導電接続時に電子部品のバンプ等の端子によって形成される空間を充填し、対向する電子部品同士の接着性を向上させることができる。即ち、異方性導電フィルムを用いた電子部品の低圧実装を可能とするため、及び異方性導電接続時の絶縁性樹脂層２の樹脂流動を抑制して導電粒子１Ａ、１Ｂの粒子捕捉性を向上させるため、絶縁性樹脂層２の粘度を高くすると共に、導電粒子１Ａ、１Ｂが位置ずれを起こさない限りで絶縁性樹脂層２の厚さは薄くすることが望ましいが、絶縁性樹脂層２の厚さを過度に薄くすると、対向する電子部品同士を接着させる樹脂量の不足を招くことから接着性の低下が懸念される。これに対し、異方性導電接続時に絶縁性樹脂層２よりも粘度が低い第２の絶縁性樹脂層４を設けることにより、電子部品同士の接着性も向上させることができ、第２の絶縁性樹脂層４の流動性が絶縁性樹脂層２よりも高いことから端子による導電粒子１Ａ、１Ｂの挟持や押し込みを阻害し難くすることができる。
　導電粒子分散層３に第２の絶縁性樹脂層４を積層する場合、第２の絶縁性樹脂層４が凹み２ｂの形成面上にあるか否かに関わらず、ツールで加圧する電子部品に第２の絶縁性樹脂層４が貼られるようにする（絶縁性樹脂層２がステージに載置される電子部品に貼られるようにする）ことが好ましい。このようにすることで、導電粒子の無用な移動を避けることができ、捕捉性を向上させることができる。
　絶縁性樹脂層２と第２の絶縁性樹脂層４との最低溶融粘度比は、差があるほど電子部品の電極やバンプによって形成される空間が第２の絶縁性樹脂層４で充填されやすくなり、電子部品同士の接着性を向上させることができる。また、この差があるほど導電粒子分散層３中に存在する絶縁性樹脂層２の移動量が相対的に少なくなり、端子間の導電粒子１Ａ、１Ｂが樹脂流動により流されにくくなることにより、端子における導電粒子１Ａ、１Ｂの捕捉性が向上するので好ましい。実用上は、絶縁性樹脂層２と第２の絶縁性樹脂層４との最低溶融粘度比は、好ましくは２以上、より好ましくは５以上、さらに好ましくは８以上である。一方、この比が大きすぎると長尺の異方性導電フィルムを巻装体にした場合に、樹脂のはみだしやブロッキングの虞があるので、実用上は１５以下が好ましい。第２の絶縁性樹脂層４の好ましい最低溶融粘度は、より具体的には、上述の比を満たし、かつ３０００Ｐａ・ｓ以下、好ましくは２０００Ｐａ・ｓ以下であり、特に１００～２０００Ｐａ・ｓである。
　なお、第２の絶縁性樹脂層４は、絶縁性樹脂層２と同様の樹脂組成物において、粘度を調整することにより形成することができる。
　また、第２の絶縁性樹脂層４の層厚は、好ましくは４～２０μｍである。もしくは、導電粒子１Ａ、１Ｂの平均粒子径Ｄに対して、好ましくは１～８倍である。
　また、絶縁性樹脂層２と第２の絶縁性樹脂層４を合わせた異方性導電フィルム１０Ｆ、１０Ｇ全体の最低溶融粘度は、実用上は８０００Ｐａ・ｓ以下、好ましくは２００～７０００Ｐａ・ｓ、より好ましくは、２００～４０００Ｐａ・ｓである。
　第２の絶縁性樹脂層４の具体的な積層態様としては、例えば、図６に示す異方性導電フィルム１０Ｆのように、導電粒子１Ａ、１Ｂが絶縁性樹脂層２の片面から突出している場合に、その突出している面に第２の絶縁性樹脂層４を積層し、第２の絶縁性樹脂層４に導電粒子１Ａ、１Ｂを食い込ませることができる。導電粒子１Ａ、１Ｂの埋込率（Ｌｂ／Ｄ）が０．９５以下の場合に、このように第２の絶縁性樹脂層４を積層することが好ましく、０．９以下の場合はより好ましい。また、平均粒子径Ｄが１０μｍ未満の場合には、このようにすることが望ましい場合がある。
　一方、図７に示す異方性導電フィルム１０Ｇのように、導電粒子１Ａ、１Ｂが埋め込まれている絶縁性樹脂層２の面と反対側の面に第２の絶縁性樹脂層４を積層してもよい。
（第３の絶縁性樹脂層）
　第２の絶縁性樹脂層４と絶縁性樹脂層２を挟んで反対側に第３の絶縁性樹脂層が設けられていてもよい。第３の絶縁性樹脂層をタック層として機能させることができる。第２の絶縁性樹脂層４と同様に、電子部品の電極やバンプによって形成される空間を充填させるために設けてもよい。
　第３の絶縁性樹脂層の樹脂組成、粘度及び厚みは第２の絶縁性樹脂層４と同様でもよく、異なっていても良い。絶縁性樹脂層２と第２の絶縁性樹脂層４と第３の絶縁性樹脂層を合わせた異方性導電フィルムの最低溶融粘度は特に制限はないが、実用上は８０００Ｐａ・ｓ以下、好ましくは２００～７０００Ｐａ・ｓ、より好ましくは、２００～４０００Ｐａ・ｓである。
＜異方性導電フィルムの製造方法＞
　本発明の異方性導電フィルムは、例えば、絶縁性樹脂層２の表面に導電粒子１Ａ、１Ｂが個々に独立した所定の規則的な配置又はランダムな分散状態で保持させ、その導電粒子１Ａ、１Ｂを平板又はローラーで絶縁性樹脂層２に押し込むことにより製造することができる。
　ここで、絶縁性樹脂層２における導電粒子１Ａ、１Ｂの埋込量Ｌｂは、導電粒子１Ａ、１Ｂの押し込み時の押圧力、温度等により調整することができ、また、凹み２ｂ、２ｃの有無、形状及び深さは、押し込み時の絶縁性樹脂層２の粘度、押込速度、温度等により調整することができる。
　また、絶縁性樹脂層２に導電粒子１Ａ、１Ｂを保持させる手法としては、特に限定されるものではないが、導電粒子１Ａ、１Ｂを規則的な配置とする場合、例えば、転写型を使用して絶縁性樹脂層２に、所定の割合で混合した導電粒子１Ａ、１Ｂを保持させる。転写型としては、例えば、シリコン、各種セラミックス、ガラス、ステンレススチールなどの金属等の無機材料や、各種樹脂等の有機材料の転写型材料に対し、フォトリソグラフ法等の公知の開口形成方法によって開口を形成したものを使用することができる。なお、転写型は、板状、ロール状等の形状をとることができる。
　絶縁性樹脂層２の導電粒子１Ａ、１Ｂがランダムな分散状態で個々に独立しないものを得る方法としては、絶縁性樹脂層２を形成する樹脂組成物に導電粒子１Ａ、１Ｂを所定の割合で混練（混合）し、それを剥離フィルム上に塗布することにより、導電粒子１Ａ、１Ｂがランダムな位置にある絶縁性樹脂層を得てもよい。
　異方性導電フィルムを用いて経済的に電子部品の接続を行うには、異方性導電フィルムはある程度の長尺であることが好ましい。そこで異方性導電フィルムは、長さを好ましくは５ｍ以上、より好ましくは１０ｍ以上、さらに好ましくは２５ｍ以上に製造する。一方、異方性導電フィルムを過度に長くすると、異方性導電フィルムを用いて電子部品の製造を行う場合に使用する従前の接続装置を使用することができなくなり、取り扱い性も劣る。そこで、異方性導電フィルムは、長さを好ましくは５０００ｍ以下、より好ましくは１０００ｍ以下、さらに好ましくは５００ｍ以下に製造する。異方性導電フィルムのこのような長尺体は、巻芯に巻かれた巻装体とすることが取り扱い性に優れる点から好ましい。
＜異方性導電フィルムの使用方法＞
　本発明の異方性導電フィルムは、ＩＣチップ、ＩＣモジュール、ＦＰＣなどの第１電子部品と、ＦＰＣ、ガラス基板、プラスチック基板、リジッド基板、セラミック基板などの第２電子部品とを異方性導電接続する際に好ましく使用することができ、特にプラスチック基板としては、高圧で圧着することにより変形やクラックが生じやすいＰＥＴ基材に端子が形成されたものをあげることができる。なお、このＰＥＴ基材は接着剤を介してポリイミド基材を積層したものであってもよい。これらの総厚は、一例として０．１５ｍｍ以下とすることができる。本発明の異方性導電フィルムを用いてＩＣチップやウェーハーをスタックして多層化してもよい。なお、本発明の異方性導電フィルムで接続する電子部品は、上述の電子部品に限定されるものではない。近年、多様化している種々の電子部品に使用することができる。本発明は、本発明の異方性導電フィルムを用いて電子部品同士が異方性導電接続されている接続構造体も包含する。また、第１の電子部品と第２の電子部品とを、その間に本発明の異方性導電フィルムを配置して異方性導電接続する工程を有する接続構造体の製造方法も包含する。
　異方性導電フィルムを用いた電子部品の接続方法としては、異方性導電フィルムの樹脂層が導電粒子分散層３の単層からなる場合、各種基板などの第２電子部品に対し、異方性導電フィルムの導電粒子１Ａ、１Ｂが表面に埋め込まれている側から仮貼りして仮圧着し、仮圧着した異方性導電フィルムの導電粒子１Ａ、１Ｂが表面に埋め込まれていない側にＩＣチップ等の第１電子部品を合わせ、熱圧着することにより製造することができる。異方性導電フィルムの絶縁性樹脂層に熱重合開始剤と熱重合性化合物だけでなく、光重合開始剤と光重合性化合物（熱重合性化合物と同一でもよい）が含まれている場合、光と熱を併用した圧着方法でもよい。このようにすれば、導電粒子の不本意な移動は最小限に抑えることができる。また、導電粒子が埋め込まれていない側を第２電子部品に仮貼りして使用してもよい。なお、第２電子部品ではなく、第１電子部品に異方性導電フィルムを仮貼りすることもできる。
　また、異方性導電フィルムが、導電粒子分散層３と第２の絶縁性樹脂層４の積層体から形成されている場合、導電粒子分散層３を各種基板などの第２電子部品に仮貼りして仮圧着し、仮圧着した異方性導電フィルムの第２の絶縁性樹脂層４側にＩＣチップ等の第１電子部品をアライメントして載置し、熱圧着する。異方性導電フィルムの第２の絶縁性樹脂層４側を第１電子部品に仮貼りしてもよい。また、導電粒子分散層３側を第１電子部品に仮貼りして使用することもできる。
　以下、本発明を実施例に基づいて具体的に説明する。
　実施例１～４、比較例１、２
（１）異方性導電フィルムの製造
　表１に示した配合で、導電粒子分散層を形成する絶縁性樹脂層形成用樹脂組成物、及び第２の絶縁性樹脂層形成用樹脂組成物をそれぞれ調製した。絶縁性樹脂層の最低溶融粘度は３０００Ｐａ・ｓ以上であり、この絶縁性樹脂層の最低溶融粘度と第２の絶縁性樹脂層の最低溶融粘度の比は２以上であった。
　一方、樹脂コア粒子の表面に約７０個のアルミナ粒子（平均粒子径１５０ｎｍ）を有し、最外層にＮｉ層（厚さ１００ｎｍ）を有する高硬度導電粒子（２０％圧縮弾性率２２０００Ｎ／ｍｍ2、平均粒子径３μｍ、積水化学工業（株）製）（特開２００６－２６９２９６号公報に記載の手法で製造されたもの）を用意し、また、高硬度導電粒子と同様の構造の低硬度導電粒子（２０％圧縮弾性率６０００Ｎ／ｍｍ2、平均粒子径３μｍ、積水化学工業（株）製）を用意した。なお、以降の実施例１～２４及び比較例１～１０においても同様に製造された積水化学工業（株）製の導電粒子を用意した。
　高硬度導電粒子と低硬度導電粒子を、それらの個数密度が表２に示す比率となるように絶縁性樹脂層（高粘度樹脂層）形成用樹脂組成物に混合し、それをバーコータ－でフィルム厚さ５０μｍのＰＥＴフィルム上に塗布し、８０℃のオーブンにて５分間乾燥させ、ＰＥＴフィルム上に高硬度導電粒子と低硬度導電粒子がランダムに分散している導電粒子分散層を形成した。この導電粒子分散層の絶縁性樹脂層の厚さは６μｍであった。また、第２の絶縁性樹脂層形成用樹脂組成物をバーコータ－でフィルム厚さ５０μｍのＰＥＴフィルム上に塗布し、８０℃のオーブンにて５分間乾燥させることにより、ＰＥＴフィルム上に厚さ１２μｍの第２の絶縁性樹脂層となる樹脂層を形成した。この樹脂層を上述の導電粒子分散層に積層し、異方性導電フィルムとした。
Figure JPOXMLDOC01-appb-T000001
（２）異方性導電フィルムの評価
　（１）で製造した実施例及び比較例の異方性導電フィルムを接続に十分な面積で裁断したものを用いて電子部品の接続構造体を作製し、（ａ）捕捉効率、（ｂ）圧痕、（ｃ）粒子潰れ率、（ｄ）抵抗値を次のように評価した。結果を表２に示す。
　（ａ）捕捉効率
　以下に示す評価用ＩＣと、この評価用ＩＣと端子パターンが対応するガラス基板と（Ｔｉ／Ａｌ配線）に異方性導電フィルムを介して２００℃、表２に記載の加圧力で５秒間加熱加圧し、評価用接続構造体を得た。
　評価用ＩＣ：
　外形　１．８×２０．０ｍｍ
　厚み　０．５ｍｍ
　バンプ仕様　サイズ３０×８５μｍ、バンプ間距離２０μｍ、バンプの表面材質Ａｕ
　加熱加圧後の端子対１００個について高硬度導電粒子及び低硬度導電粒子の捕捉数を計測し、その平均を求めた。また、加熱加圧前に端子上に存在する高硬度導電粒子及び低硬度導電粒子の理論値を、［端子１００個分の端子面積］×［導電粒子の個数密度］から算出しておき、計測した導電粒子の捕捉数の理論値に対する比率を求め、次の基準で評価した。実用上、Ｂ評価以上が好ましい。
　捕捉効率評価基準
　Ａ：３０％以上
　Ｂ：１５％以上３０%未満
　Ｃ：１５％未満
（ｂ）圧痕
　（ａ）で製造した評価用接続構造体における高硬度導電粒子及び低硬度導電粒子の圧痕を金属顕微鏡により観察し、加熱加圧後の端子対５個について高硬度導電粒子及び低硬度導電粒子の圧痕（捕捉）数を画像解析ソフトＷｉｎＲＯＯＦ（三谷商事株式会社）を用いて計測し、その平均を求めた。また、加熱加圧前に端子上に存在する高硬度導電粒子及び低硬度導電粒子の理論値を、［端子５個分の端子面積］×［導電粒子の個数密度］から算出しておき、計測した導電粒子の圧痕（捕捉）数の理論値に対する比率を求め、次の基準で評価した。なお、確認された圧痕は、導電粒子がランダムに配置されている分散型の異方性導電フィルムではバンプ５個の圧痕の合計が１００個程度であり、後述する、導電粒子が正方格子に配列している整列型の異方性導電フィルムではバンプ５個の圧痕の合計が２００個程度であった。
　圧痕評価基準
　ＯＫ：理論値の５０％以上が圧痕として認識できた場合
　ＮＧ：理論値の５０％未満が圧痕として認識できた場合
（ｃ）粒子潰れ率
　（ａ）で製造した評価用接続構造体の製造直後のもの（初期）、及び（ａ）で製造した評価用接続構造体を温度８５℃、湿度８５％ＲＨの恒温槽に５００時間置いたもの（５００ｈ）のそれぞれについて、対向する端子間の距離を圧着後の粒子径として計測し、その平均粒子径を求めた。一方、圧着前の平均粒子径も求めておき、次式により粒子潰れ率を算出し、次の基準で評価した。実用上、Ｂ評価以上が好ましい。
　粒子潰れ率（％）
＝（［圧着前の平均粒子径］－［圧着後の平均粒子径］）×１００／［圧着前の平均粒子径］
　初期及び５００ｈにおける粒子潰れ率評価基準
　Ａ：１０％以上
　Ｂ：５％以上１０％未満
　Ｃ：５％未満
（ｄ）抵抗値
　（ａ）で製造した評価用接続構造体の製造直後のもの（初期）、及び（ａ）で製造した評価用接続構造体を温度８５℃、湿度８５％ＲＨの恒温槽に５００時間置いたもの（５００ｈ）のそれぞれについて、導通抵抗を４端子法で測定し、次の基準で評価した。抵抗値は、実用上Ｂ評価以上が好ましい。
　初期における抵抗値評価基準
　Ａ：３Ω未満
　Ｂ：３Ω以上５Ω未満
　Ｃ：５Ω以上１０Ω未満
　Ｄ：１０Ω以上
　５００ｈにおける抵抗値評価基準
　Ａ：３Ω未満
　Ｂ：３Ω以上５Ω未満
　Ｃ：５Ω以上１０Ω未満
　Ｄ：１０Ω以上
　実施例５～８、比較例３、４
　実施例１と同様の導電粒子を用意した。ただし、樹脂コア粒子の２０％圧縮弾性率を調整することにより、高硬度導電粒子として、２０％圧縮弾性率が１４０００Ｎ／ｍｍ2の導電粒子（平均粒子径３μｍ）と、低硬度導電粒子として、２０％圧縮弾性率が６０００Ｎ／ｍｍ2の導電粒子（平均粒子径３μｍ）を用意した。
　この高硬度導電粒子と低硬度導電粒子を表３に示す比率となるように絶縁性樹脂層（高粘度樹脂層）形成用樹脂組成物に混合した以外は実施例１と同様にして高硬度導電粒子と低硬度導電粒子がランダムに分散している異方性導電フィルムを製造した。
　また、実施例１と同様にして（ａ）捕捉効率、（ｂ）圧痕、（ｃ）粒子潰れ率、（ｄ）抵抗値を評価した。結果を表３に示す。
　実施例９～１２、比較例５
　実施例１と同様の導電粒子を用意した。ただし、樹脂コア粒子の２０％圧縮弾性率を調整することにより、高硬度導電粒子として、２０％圧縮弾性率が９０００Ｎ／ｍｍ2の導電粒子（平均粒子径３μｍ）と、低硬度導電粒子として、２０％圧縮弾性率が６０００Ｎ／ｍｍ2の導電粒子（平均粒子径３μｍ）を用意した。
　この高硬度導電粒子と低硬度導電粒子を表４に示す比率となるように絶縁性樹脂層（高粘度樹脂層）形成用樹脂組成物に混合した以外は実施例１と同様にして高硬度導電粒子と低硬度導電粒子がランダムに分散している異方性導電フィルムを製造した。
　また、実施例１と同様にして（ａ）捕捉効率、（ｂ）圧痕、（ｃ）粒子潰れ率、（ｄ）抵抗値を評価した。結果を表４に示す。
　実施例１３～１６、比較例６、７
　表１に示した配合で、導電粒子分散層を形成する絶縁性樹脂層形成用樹脂組成物を調製し、これをバーコータ－でフィルム厚さ５０μｍのＰＥＴフィルム上に塗布し、８０℃のオーブンにて５分間乾燥させ、ＰＥＴフィルム上に絶縁性樹脂層を形成した。この絶縁性樹脂層の厚さは６μｍであった。また、表１に示した配合で第２の絶縁性樹脂層形成用樹脂組成物を調製し、同様にして厚さ１２μｍの樹脂層を形成した。
　また、実施例１と同様の２０％圧縮弾性率が２２０００Ｎ／ｍｍ2の高硬度導電粒子と、２０％圧縮弾性率が６０００Ｎ／ｍｍ2の低硬度導電粒子を用意した。
　一方、導電粒子が図１Ａに示すように正方格子配列となり、高硬度導電粒子と低硬度導電粒子の全体の個数密度が表５に示す数値となるように金型を作製し、この金型に公知の透明性樹脂のペレットを溶融させた状態で流し込み、冷やして固めることで、凹部が図１Ａに示す配列パターンの樹脂型を形成した。
　この樹脂型の凹部に、高硬度導電粒子と低硬度導電粒子とを表５に示す比率となるように混合して充填し、その上に上述の絶縁性樹脂層を被せ、６０℃、０．５ＭＰａで押圧することで貼着させた。そして、型から絶縁性樹脂層を剥離し、絶縁性樹脂層上の導電粒子を（押圧条件：６０～７０℃、０．５ＭＰａ）で該絶縁性樹脂層内に押し込み、導電粒子分散層を形成した。この場合、埋込率は９９．９％とした。導電粒子が埋め込まれている導電粒子分散層の表面に、上述の第２の絶縁性樹脂層形成用樹脂組成物から形成した樹脂層を積層し、高硬度導電粒子と低硬度導電粒子が全体として正方格子に配列している異方性導電フィルムを製造した。
　こうして得た異方性導電フィルムを接続に十分な面積で裁断し、裁断した異方性導電フィルムを使用して実施例１と同様に評価用接続構造体を作製し、（ａ）捕捉効率、（ｂ）圧痕、（ｃ）粒子潰れ率、（ｄ）抵抗値を評価した。結果を表５に示す。
　実施例１７～２０、比較例８、９
　実施例５と同様の２０％圧縮弾性率が１４０００Ｎ／ｍｍ2の高硬度導電粒子と、２０％圧縮弾性率が６０００Ｎ／ｍｍ2の低硬度導電粒子を用意した。
　この高硬度導電粒子と低硬度導電粒子を表６に示す比率となるように混合して樹脂型に充填する以外は実施例１３と同様にして高硬度導電粒子と低硬度導電粒子が全体として正方格子に配列している異方性導電フィルムを製造した。
　また、実施例１と同様に接続に十分な面積で裁断し、裁断した異方性導電フィルムを使用して（ａ）捕捉効率、（ｂ）圧痕、（ｃ）粒子潰れ率、（ｄ）抵抗値を評価した。結果を表６に示す。
　実施例２１～２４、比較例１０
　実施例９と同様の２０％圧縮弾性率が９０００Ｎ／ｍｍ2の高硬度導電粒子と、２０％圧縮弾性率が６０００Ｎ／ｍｍ2の低硬度導電粒子を用意した。
　この高硬度導電粒子と低硬度導電粒子を表７に示す比率となるように混合して樹脂型に充填する以外は実施例１３と同様にして高硬度導電粒子と低硬度導電粒子が全体として正方格子に配列している異方性導電フィルムを製造した。
　また、実施例１と同様に接続に十分な面積で裁断し、裁断した異方性導電フィルムを使用して（ａ）捕捉効率、（ｂ）圧痕、（ｃ）粒子潰れ率、（ｄ）抵抗値を評価した。結果を表７に示す。
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000007
　表２から、２０％圧縮弾性率が２２０００Ｎ／ｍｍ2の高硬度導電粒子と２０％圧縮弾性率が６０００Ｎ／ｍｍ2の低硬度導電粒子の双方を含有し、導電粒子がランダムに配置されている実施例１～４の異方性導電フィルムによれば、いずれも圧痕の評価が良好であり、導通特性（初期抵抗値、５００ｈ抵抗値）も良好なことがわかる。これに対し、２０％圧縮弾性率が２２０００Ｎ／ｍｍ2の高硬度導電粒子のみを含有する比較例１の異方性導電フィルムも、２０％圧縮弾性率が６０００Ｎ／ｍｍ2の低硬度導電粒子のみを含有する比較例２の異方性導電フィルムも、圧痕の評価が劣っており、さらに高硬度導電粒子のみを含有する比較例１の異方性導電フィルムは、導通特性（５００ｈ）が劣っている。このことから、導電粒子が低硬度導電粒子のみであると硬さが足りないために圧痕が見え難い状態になること、また、導電粒子が高硬度導電粒子のみであると硬すぎて導電粒子の圧縮が不十分となることにより圧痕が見え難いことが推察される。なお、高硬度導電粒子のみの場合に、圧痕の評価がＯＫであった場合でも、高硬度導電粒子と低硬度導電粒子が混合されている実施例の方が圧痕は観察されやすかった。
　表５から、２０％圧縮弾性率が２２０００Ｎ／ｍｍ2の高硬度導電粒子と２０％圧縮弾性率が６０００Ｎ／ｍｍ2の低硬度導電粒子の双方を含有し、導電粒子が正方格子に配列している実施例１３～１６においても、上述の実施例１～４と同様に、いずれも圧痕の評価が良好であり、導通特性（初期抵抗値、５００ｈ抵抗値）も良好なことがわかる。高硬度導電粒子又は低硬度導電粒子のいずれかしか含有していない比較例６、７では、圧痕に問題があった。
　表３から、２０％圧縮弾性率が１４０００Ｎ／ｍｍ2の高硬度導電粒子と、２０％圧縮弾性率が６０００Ｎ／ｍｍ2の低硬度導電粒子の双方を含有し、導電粒子がランダムに配置されている実施例５～８の異方性導電フィルムは、いずれも圧痕の評価が良好であり、導通特性（初期抵抗値、５００ｈ抵抗値）も良好であることがわかる。特に異方性導電接続時の圧力が６０ＭＰａという低圧であっても良好である。これに対し、２０％圧縮弾性率が１４０００Ｎ／ｍｍ2の高硬度導電粒子のみを含有する比較例３の異方性導電フィルムは圧痕の評価が劣っており、さらに異方性導電接続時の圧力が６０ＭＰａであると、導通特性（５００ｈ）も劣っている。また、導電粒子として低硬度導電粒子のみを含有している比較例４の異方性導電フィルムは圧痕に問題があった。
　表６から、２０％圧縮弾性率が１４０００Ｎ／ｍｍ2の高硬度導電粒子と２０％圧縮弾性率が６０００Ｎ／ｍｍ2の低硬度導電粒子の双方を含有し、導電粒子が正方格子に配列している実施例１７～２０においても、上述の実施例５～８と同様に、いずれも圧痕の評価が良好であり、導通特性（初期抵抗値、５００ｈ抵抗値）も良好なことがわかる。高硬度導電粒子又は低硬度導電粒子のいずれかしか含有していない比較例８、９では、圧痕に問題があった。
　表４からも、２０％圧縮弾性率が９０００Ｎ／ｍｍ2の高硬度導電粒子と、２０％圧縮弾性率が６０００Ｎ／ｍｍ2の低硬度導電粒子の双方を含有する実施例９～１２の異方性導電フィルムは、いずれも圧痕の評価が良好であり、導通特性（初期抵抗値、５００ｈ抵抗値）も良好であり、特に異方性導電接続時の圧力が６０ＭＰａという低圧であっても良好なことがわかる。また、導電粒子として低硬度導電粒子のみを含有している比較例５の異方性導電フィルムは圧痕に問題があった。
　表７から、２０％圧縮弾性率が９０００Ｎ／ｍｍ2の高硬度導電粒子と２０％圧縮弾性率が６０００Ｎ／ｍｍ2の低硬度導電粒子の双方を含有し、導電粒子が正方格子に配列している実施例２１～２４においても、上述の実施例９～１２と同様に、いずれも圧痕の評価が良好であり、導通特性（初期抵抗値、５００ｈ抵抗値）も良好であり、特に異方性導電接続時の圧力が６０ＭＰａという低圧であっても良好なことがわかる。また、導電粒子として低硬度導電粒子のみを含有している比較例１０の異方性導電フィルムは圧痕に問題があった。
　１Ａ　高硬度導電粒子
　１Ｂ　低硬度導電粒子
　２　絶縁性樹脂層
　２ｂ　凹み（傾斜）
　２ｃ　凹み（起伏）
　３　導電粒子分散層
　４　第２の絶縁性樹脂層
１０Ａ、１０Ｂ、１０Ｃ、１０Ｄ、１０Ｅ、１０Ｆ、１０Ｇ　異方性導電フィルム
　Ｄ　　導電粒子の平均粒子径
　Ｌａ　絶縁性樹脂層の層厚　
　Ｌｂ　隣接する導電粒子間の中央部における接平面と導電粒子最深部との距離
　Ｌｃ　傾斜又は起伏における導電粒子の露出（直上）部分の径　
　Ｌｄ　導電粒子の周り又は直上の絶縁性樹脂層の傾斜又は起伏の最大径
　Ｌｅ　導電粒子の周りの絶縁性樹脂層における傾斜の最大深さ
　Ｌｆ　導電粒子の直上の絶縁性樹脂層における起伏の最大深さ

Claims (13)

  1. 　絶縁性樹脂層に、導電粒子として、２０％圧縮弾性率が８０００～２８０００Ｎ／ｍｍ2の高硬度導電粒子と、該高硬度導電粒子よりも２０％圧縮弾性率が低い低硬度導電粒子が分散している異方性導電フィルムであって、導電粒子全体の個数密度が６０００個／ｍｍ2以上であり、低硬度導電粒子の個数密度が導電粒子全体の１０％以上である異方性導電フィルム。
  2. 　低硬度導電粒子の２０％圧縮弾性率が、高硬度導電粒子の２０％圧縮弾性率の１０％以上７０％以下である請求項１記載の異方性導電フィルム。
  3. 　低硬度導電粒子の個数密度が導電粒子全体の２０％以上８０％以下である請求項１又は２記載の異方性導電フィルム。
  4. 　導電粒子全体の平均粒子径が１０μｍ未満で、導電粒子全体の個数密度が６０００個／ｍｍ2以上４２０００個／ｍｍ2以下である請求項１～３のいずれかに記載の異方性導電フィルム。
  5. 　導電粒子全体の平均粒子径が１０μｍ以上で、導電粒子全体の個数密度が２０個／ｍｍ2以上２０００個／ｍｍ2以下である請求項１～３のいずれかに記載の異方性導電フィルム。
  6. 　高硬度導電粒子と低硬度導電粒子を含む導電粒子がフィルムの平面視で規則的に配置されており、フィルム厚方向の位置が揃っている請求項１～５のいずれかに記載の異方性導電フィルム。
  7. 　高硬度導電粒子と低硬度導電粒子を含む導電粒子同士が互いに非接触で存在する個数割合が９５％以上である請求項６記載の異方性導電フィルム。
  8. 　高硬度導電粒子と低硬度導電粒子がランダムに分散している請求項１～５のいずれかに記載の異方性導電フィルム。
  9. 　高硬度導電粒子及び低硬度導電粒子の周囲の絶縁性樹脂層の表面が、隣接する導電粒子間の中央部における絶縁性樹脂層の接平面に対して傾斜又は起伏を有する請求項１～８のいずれかに記載の異方性導電フィルム。
  10. 　前記傾斜では、高硬度導電粒子及び低硬度導電粒子の周りの絶縁性樹脂層の表面が、前記接平面に対して欠けており、前記起伏では、高硬度導電粒子及び低硬度導電粒子の直上の絶縁性樹脂層の樹脂量が、前記高硬度導電粒子及び低硬度導電粒子の直上の絶縁性樹脂層の表面が該接平面にあるとしたときに比して少ない請求項９記載の異方性導電フィルム。
  11. 　請求項１～１０のいずれかに記載の異方性導電フィルムで第１の電子部品と第２の電子部品とが異方性導電接続されている接続構造体。
  12. 　第１の電子部品においてＰＥＴ基材に端子が形成されている請求項１１記載の接続構造体。
  13. 　請求項１１記載の接続構造体の製造方法であって、第１の電子部品と第２の電子部品とを、その間に請求項１～１０のいずれかに記載の異方性導電フィルムを配置して、異方性導電接続する工程を有する製造方法。
PCT/JP2017/041684 2016-12-01 2017-11-20 異方性導電フィルム WO2018101106A1 (ja)

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KR1020217013457A KR102519781B1 (ko) 2016-12-01 2017-11-20 이방성 도전 필름
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