JP6483958B2 - Conductive film and connection structure - Google Patents

Description

  The present invention relates to a conductive film containing conductive particles and a binder resin. The present invention also relates to a connection structure using the conductive film.

  Anisotropic conductive materials such as anisotropic conductive pastes and anisotropic conductive films are widely known. In the anisotropic conductive material, conductive particles are dispersed in a binder resin.

  In order to obtain various connection structures, the anisotropic conductive material is, for example, a connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)) or a connection between a semiconductor chip and a flexible printed circuit board (COF ( Chip on Film)), connection between a semiconductor chip and a glass substrate (COG (Chip on Glass)), connection between a flexible printed circuit board and a glass epoxy substrate (FOB (Film on Board)), and the like.

  As an example of the anisotropic conductive material, the following Patent Document 1 discloses an anisotropic conductive film containing conductive particles. This anisotropic conductive film is used for circuit connection. In the anisotropic conductive film, the content ratio of the conductive particles in a region from one surface to a distance twice the average particle diameter of the conductive particles along the thickness direction is represented by the following formula (I): The condition represented by is satisfied. Moreover, the minimum value in 40-250 degreeC of the melt viscosity of the said anisotropic conductive film is 1000 Pa.s or less.

C ≧ C ₀ × 0.8 (I)

In the above formula (I), C represents the content of the conductive particles in the region (mass%), C ₀ is the conductivity in the region of the one surface of the anisotropic conductive film to the other surface The content ratio (% by mass) of the particles is shown.

JP 2011-175846 A

  In recent years, in various electronic components and the like, connection target members connected by an anisotropic conductive film have been made thinner. For this reason, the request | requirement of thickness reduction of the said anisotropic conductive film is increasing.

  However, when the anisotropic conductive film is thin, the unevenness on the surface of the connection target member is not sufficiently filled with the anisotropic conductive film, and voids are easily generated. When a void arises, the adhesiveness of an anisotropic conductive film and a connection object member will become low.

  On the other hand, when the melt viscosity of the anisotropic conductive film is lowered in order to increase the filling property of the anisotropic conductive film with respect to the unevenness of the surface of the connection target member, the gap between the upper and lower electrodes (lines) is reduced when the electrodes are connected. The number of conductive particles to be arranged is reduced, and the conductive particles easily flow out between the electrodes (spaces) adjacent to each other in the lateral direction. That is, there is a problem that the conductive particles are easily arranged not only in the line (L) where the electrode is formed but also in the space (S) where the electrode is not formed. For this reason, the connection resistance between electrodes becomes high, or the connection reliability between electrodes falls. Furthermore, it is sometimes necessary to use a large amount of conductive particles on the assumption that conductive particles are also arranged in the space. Furthermore, there is a problem that poor insulation is likely to occur as a result of the conductive particles being arranged in the space.

  An object of the present invention is to provide a conductive film that can suppress the generation of voids and increase the connection reliability between electrodes when used for electrical connection between electrodes, and uses the conductive film. Is to provide a connection structure.

According to a wide aspect of the present invention, the conductive particle includes a conductive resin and a binder resin, the conductive particle has a plurality of protrusions on a conductive surface, and the total surface area of the conductive particle is 100%. The conductive particles have a surface area of 50% or more and 95% or less where the protrusions are present, and the surface area of the conductive particles where the protrusions are not present is 5% or more and 50% or less. 100 compression modulus of when compressed by 10% at ° C. is 3000N / mm ² or more and 10000 N / mm ² or less, the melt viscosity at 100 ° C. is 300 Pa · s or more, or less 1000 Pa · s, the conductive film Provided.

  On the specific situation with the electrically conductive film which concerns on this invention, the average particle diameter of the said electroconductive particle is 2 micrometers or more and 5 micrometers or less, and the average height of the said protrusion in the said electroconductive particle is 50 nm or more and 500 nm or less.

  In a specific aspect of the conductive film according to the present invention, the conductive film is a single layer film including the conductive particles and the binder resin, or the first layer including the conductive particles and the binder resin; A multilayer film that is laminated on one side of the first layer and has a second layer that does not contain the conductive particles and contains the binder resin, and is a single-layer film, When the thickness of the single layer film is 5 to 7 times the average particle diameter of the conductive particles, and the multilayer film is a multilayer film, the thickness of the multilayer film is the average particle of the conductive particles. It is 5 times or more and 8 times or less of the diameter.

  In a specific aspect of the conductive film according to the present invention, in the case of the multilayer film, the thickness of the first layer containing the conductive particles is at least twice the average particle diameter of the conductive particles, The thickness of the second layer which is 4 times or less and does not include the conductive particles is 1 to 3 times the thickness of the first layer.

  The conductive film according to the present invention may be a single layer film containing the conductive particles and the binder resin. The conductive film according to the present invention includes a first layer including the conductive particles and the binder resin, and is laminated on one side of the first layer, and does not include the conductive particles and the binder resin. It may be a multilayer film having a second layer containing

  According to a wide aspect of the present invention, a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, the first connection target member, and the A connection portion connecting the second connection target member, the connection portion is formed of the conductive film described above, and the first electrode and the second electrode are the conductive A connection structure is provided that is electrically connected by particles.

The conductive film according to the present invention includes conductive particles and a binder resin. Furthermore, in the conductive film according to the present invention, the conductive particles have a plurality of protrusions on a conductive surface, and the conductive particles In the total surface area of 100%, the surface area of the conductive particles with the protrusions is 50% or more and 95% or less, and the surface area of the conductive particles without the protrusions is 5% or more and 50%. or less, the compression modulus when the conductive particles are compressed 10% at 100 ° C. is 3000N / mm ² or more and 10000 N / mm ² or less, melting at 100 ° C. of the conductive film of the present invention Since the viscosity is 300 Pa · s or more and 1000 Pa · s or less, when the conductive film is used for electrical connection between electrodes, generation of voids is suppressed and connection reliability between electrodes is reduced. It is possible to increase.

FIG. 1 is a cross-sectional view showing a conductive film according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a conductive film according to another embodiment of the present invention. FIG. 3 is a cross-sectional view showing conductive particles used in the conductive film shown in FIGS. FIG. 4 is a cross-sectional view showing a first modification of the conductive particles. FIG. 5 is a cross-sectional view showing a second modification of the conductive particles. 6 is a cross-sectional view schematically showing an example of a connection structure using the conductive film shown in FIG.

  Details of the present invention will be described below.

The conductive film according to the present invention includes conductive particles and a binder resin. The conductive particles have a plurality of protrusions on the conductive surface. Of the total surface area of 100% of the conductive particles, the surface area of the conductive particles where the protrusions are present is 50% or more and 95% or less, and the surface area of the conductive particles where the protrusions are not present is 5%. Above, it is 50% or less. In the present invention, the surface area of the portion having the protrusion is large. Compression modulus when the conductive particles are compressed 10% at 100 ° C. (10% K value) of 3000N / mm ² or more and 10000 N / mm ² or less. The melt viscosity at 100 ° C. of the conductive film according to the present invention is 300 Pa · s or more and 1000 Pa · s or less.

  Since the conductive film according to the present invention has the above-described configuration, when the conductive film according to the present invention is used for electrical connection between the electrodes, generation of voids is suppressed and connection reliability between the electrodes is reduced. Can be increased.

  In recent years, with the downsizing of electronic devices, the distance between the line (L) where the electrode is formed and the space (S) where the electrode is not formed has become narrower. For example, it is necessary to electrically connect fine electrodes having L / S of 30 μm or less / 30 μm or less. In the case of electrically connecting electrodes having a small L / S, when a conventional conductive film is used, the number of conductive particles arranged on the line (L) tends to be small, so that the connection resistance increases. In addition, since a large number of conductive particles are easily arranged in the space (S), there is a problem that insulation failure is particularly likely to occur.

  On the other hand, by using the conductive film according to the present invention, the electrodes can be efficiently arranged in the line (L), the connection resistance can be effectively reduced, and the conductive material in the space (S). It becomes difficult to arrange the conductive particles, and it is possible to effectively suppress the occurrence of insulation failure.

  The surface area of the conductive particles where the protrusions are present can be measured by analyzing the image after the particles are photographed from above with a scanning electron microscope (SEM). The portion where the protrusion is present is a raised portion on the conductive surface of the conductive particle. The portion without the protrusion is a portion that is not raised on the conductive surface of the conductive particle.

  The surface area of the portion where the protrusions are present in the total surface area of 100% of the conductive particles is 50% or more, preferably 60% or more, more preferably 70% or more. Of the total surface area of the conductive particles 100%, the surface area of the portion having the protrusions is 95% or less, preferably 90% or less, more preferably 85% or less. Of the total surface area of 100% of the conductive particles, the surface area of the portion without the protrusion is 5% or more, preferably 10% or more. In 100% of the total surface area of the conductive particles, the surface area of the portion without the protrusion is 50% or less, preferably 40% or less, more preferably 30% or less. When the surface area of the portion where the protrusion is present is relatively increased, the number of protrusions that come into contact with the electrode is increased, so that the conductivity is further improved. When the surface area of the portion without the protrusion is relatively increased, the aspect ratio of each protrusion is further increased, and the amount of biting into the electrode is increased, thereby further improving the conductivity. In particular, in 100% of the total surface area of the conductive particles, the surface area of the portion with the protrusions is 60% or more and the surface area of the portion without the protrusions is 40% or less. Connection reliability is further improved. In particular, in 100% of the total surface area of the conductive particles, the surface area of the portion with the protrusion is 85% or less and the surface area of the portion without the protrusion is 15% or more. The connection reliability between them becomes even better.

Compression modulus when the conductive particles are compressed 10% at 100 ° C. (10% K value), 3000N / mm ² or more and 10000 N / mm ² or less. The 10% K value is preferably 4000 N / mm ² or more, preferably 8000 N / mm ² or less. When the 10% K value is equal to or higher than the lower limit, the resin rejection during pressure bonding is further improved. When the 10% K value is not more than the above upper limit, the contact area of the conductive particles to the electrode becomes even better. In particular, when the 10% K value at 100 ° C. of the conductive particles is 4000 N / mm ² or more, the arrangement accuracy of the conductive particles is further improved. In particular, when the 10% K value at 100 ° C. of the conductive particles is 8000 N / mm ² or less, the connection reliability between the electrodes is further improved.

  The temperature at which the 10% K value is measured is set to 100 ° C., in many cases, the 10% compression state in the actual crimping process is achieved near 100 ° C., and the 10% compression state is 100 ° C. This is because it is desirable to achieve the temperature around 0 ° C. When the 10% K value at 100 ° C. of the conductive particles is within the above range, the versatility of the conductive film is excellent.

  The compression elastic modulus (10% K value) at 100 ° C. is measured as follows.

  With the stage on which the particles of the micro-compression tester are placed maintained at 100 ° C., with a smooth indenter end face of a cylinder (diameter 50 μm, made of diamond) under conditions of a compression speed of 0.33 mN / sec and a maximum test load of 20 mN. Compress the conductive particles. The load value (N) and compression displacement (mm) at this time are measured. From the measured value obtained, the compression elastic modulus can be obtained by the following formula. As the micro compression tester, for example, “Fischer Scope H-100” manufactured by Fischer is used.

10% K value (N / mm ² ) = (3/2 ^1/2 ) · F · S ⁻³ / ² · R ^−1/2
F: Load value when the conductive particles are 10% compressively deformed (N)
S: Compression displacement (mm) when the conductive particles are 10% compressively deformed
R: radius of conductive particles (mm)

  The compression elastic modulus universally and quantitatively represents the hardness of the conductive particles. By using the compression elastic modulus, the hardness of the conductive particles can be expressed quantitatively and uniquely.

  The conductive film has a melt viscosity at 100 ° C. of 300 Pa · s or more and 1000 Pa · s or less. The melt viscosity at 100 ° C. of the conductive film is preferably 400 Pa · s or more, and preferably 800 Pa · s or less. When the melt viscosity is not less than the above lower limit, the resin exclusion property between the particles and the electrode is further improved. When the melt viscosity is less than or equal to the above upper limit, the placement accuracy of the particles on the electrode is further improved. In particular, if the melt viscosity at 100 ° C. of the conductive film is 400 Pa · s or more, generation of voids can be suppressed considerably.

  The temperature at which the melt viscosity is measured is set to 100 ° C., because the greatest influence of the melt viscosity on the placement accuracy of the conductive particles in the actual crimping process is often achieved at around 100 ° C. This is because it is desirable that the greatest influence of the melt viscosity on the placement accuracy of the conductive particles is achieved around 100 ° C. When the melt viscosity at 100 ° C. of the conductive film is within the above range, the versatility of the conductive film is excellent.

  The melt viscosity can be measured using a viscoelasticity measuring device. Examples of the viscoelasticity measuring apparatus include “ARES-G2” manufactured by TA Instruments.

  In the conductive film according to the present invention, in particular, L / S indicating the line (L) where the electrode is formed and the space (S) where the electrode is not formed is 30 μm or less / 30 μm or less. In this case, the connection reliability between the electrodes can be effectively increased, and when the L / S is 25 μm or less / 25 μm or less, the connection reliability between the electrodes can be further effectively increased. When / S is 20 μm or less / 20 μm or less, the connection reliability between the electrodes can be further effectively improved, and when L / S is 15 μm or less / 15 μm or less, the connection reliability between the electrodes Can be increased particularly effectively.

  In addition, since the connection reliability between the electrodes can be enhanced by the conductive film according to the present invention, the line (L) where the electrodes are formed is preferably 30 μm or less, more preferably 25 μm or less, and still more preferably. It is 20 μm or less, particularly preferably 15 μm or less. The line (L) is preferably larger than the average particle size of the conductive particles, more preferably 1.1 times or more of the average particle size of the conductive particles, and even more preferably 2 times or more. It is particularly preferably 3 times or more.

  Further, since the connection reliability between the electrodes can be enhanced by the conductive film according to the present invention, the space (S) where the electrodes are not formed is preferably 30 μm or less, more preferably 25 μm or less, and still more preferably. It is 20 μm or less, particularly preferably 15 μm or less. The space (S) is preferably larger than the average particle size of the conductive particles, more preferably 1.1 times or more of the average particle size of the conductive particles, and even more preferably 2 times or more. It is particularly preferably 3 times or more.

  Hereinafter, the present invention will be further clarified by describing specific embodiments and examples of the present invention with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a conductive film according to an embodiment of the present invention.

  The conductive film 1 shown in FIG. 1 is a single layer film. The conductive film 1 includes conductive particles 21 and a binder resin 11. In the conductive film 1, the conductive particles 21 are preferably contained uniformly. In the conductive film 1, the conductive particles 21 may be unevenly distributed in the thickness direction. There are many conductive particles 21 on the first main surface side of the conductive film 1 and few conductive particles 21 on the second main surface side opposite to the first main surface of the conductive film. Also good.

  FIG. 2 is a cross-sectional view showing a conductive film according to another embodiment of the present invention.

  A conductive film 1A shown in FIG. 2 is a multilayer film (laminated film). The conductive film 1 </ b> A has a first layer 2 and a second layer 3 laminated on one side of the first layer 2. The first layer 2 includes conductive particles 21 and a binder resin 11A. The second layer 3 does not include conductive particles and includes the binder resin 11B. The binder resin contained in the first layer and the binder resin contained in the second layer may be the same or different.

  The conductive film according to the present invention is a single layer film containing the conductive particles and the binder resin, or a first layer containing the conductive particles and the binder resin, and the first layer. It is preferable that it is a multilayer film which is laminated | stacked on the single side | surface of a layer, and does not contain the said electroconductive particle and has the 2nd layer containing the said binder resin. The conductive film may be a single layer film containing the conductive particles and the binder resin. The conductive film includes a first layer including the conductive particles and the binder resin, and is laminated on one side of the first layer, and does not include the conductive particles and includes the binder resin. A multilayer film having two layers may be used.

  When the conductive film is the single-layer film, the thickness of the single-layer film is preferably at least 3 times, more preferably at least 4 times, and even more preferably at least 5 times the average particle diameter of the conductive particles. Preferably, it is 10 times or less, more preferably 9 times or less, still more preferably 7 times or less. In this case, when the conductive film is used for electrical connection between the electrodes, generation of voids can be further suppressed and connection reliability between the electrodes can be further enhanced. Most preferably, the thickness of the single layer film is not less than 5 times and not more than 7 times the average particle diameter of the conductive particles.

  When the conductive film is the multilayer film, the thickness of the multilayer film is preferably at least 3 times the average particle diameter of the conductive particles, more preferably at least 4 times, even more preferably at least 5 times, preferably Is preferably 10 times or less, more preferably 9 times or less, and still more preferably 8 times or less. In this case, when the conductive film is used for electrical connection between the electrodes, generation of voids can be further suppressed and connection reliability between the electrodes can be further enhanced. Most preferably, the thickness of the multilayer film is not less than 5 times and not more than 8 times the average particle diameter of the conductive particles.

  When the conductive film is the multilayer film, the thickness of the first layer containing the conductive particles is preferably 1 or more times the average particle diameter of the conductive particles, more preferably 2 or more times, Preferably it is 5 times or less, more preferably 4 times or less, and the thickness of the second layer not containing the conductive particles is preferably 1 or more times, preferably 5 times the thickness of the first layer. Hereinafter, it is more preferably 3 times or less. In this case, when the conductive film is used for electrical connection between the electrodes, generation of voids can be further suppressed and connection reliability between the electrodes can be further enhanced. The thickness of the first layer containing the conductive particles is most preferably 2 to 4 times the average particle diameter of the conductive particles, and the second layer does not contain the conductive particles. Most preferably, the thickness of the layer is 1 to 3 times the thickness of the first layer.

  Next, the conductive particles contained in the conductive film will be described below.

  FIG. 3 is a cross-sectional view showing conductive particles used in the conductive films 1 and 1A shown in FIGS.

  The conductive particles 21 shown in FIG. 3 have base material particles 22 and conductive portions 23 arranged on the surface of the base material particles 22. In the conductive particles 21, the conductive portion 23 is a conductive layer. The conductive portion 23 covers the surface of the base particle 22. The conductive particle 21 is a coated particle in which the surface of the base particle 22 is coated with the conductive portion 23.

  The said electroconductive particle should just have an electroconductive part. Like the electroconductive particle 21, the center particle | grains from which a center part differs from an electroconductive part may be sufficient. The entirety of the conductive particles may be a conductive portion. In the conductive particles, an insulating material such as insulating particles may be disposed on the outer surface of the conductive portion.

  The conductive particles 21 have protrusions 21a on the conductive surface. The conductive portion 23 has a protrusion 23a on the surface (the outer surface of the conductive layer). There are a plurality of protrusions 21a and 23a.

  The conductive particles 21 have a plurality of core substances 24 on the surface of the substrate particles 22. The conductive portion 23 covers the base particle 22 and the core substance 24. By covering the core substance 24 with the conductive portion 23, the conductive particle 21 has a plurality of protrusions 21 a on the surface. The surface of the conductive portion 23 is raised by the core substance 24, and a plurality of protrusions 21a are formed.

  FIG. 4 is a cross-sectional view showing a first modification of the conductive particles.

  The conductive particles 31 shown in FIG. 4 have base material particles 22 and conductive portions 23 </ b> A arranged on the surface of the base material particles 22. The conductive portion 23A is a conductive layer. The conductive particles 21 and the conductive particles 31 are different only in the presence or absence of the core substance 24. The conductive particles 31 do not have a core substance.

  The conductive particles 31 have protrusions 31a on the conductive surface. The conductive portion 23A has a protrusion 23Aa on the surface (the outer surface of the conductive layer). There are a plurality of protrusions 31a and 23Aa.

  The conductive portion 23A has a first portion and a second portion that is thicker than the first portion. Accordingly, the conductive portion 23A has a protrusion 23Aa on the surface (the outer surface of the conductive layer). A portion excluding the plurality of protrusions 31a and 23Aa is the first portion of the conductive portion 23A. The plurality of protrusions 31a and 23Aa are the second portions where the conductive portion 23A is thick.

  In order to form the protrusions 31a and 23Aa as in the case of the conductive particles 31, it is not always necessary to use a core substance.

  FIG. 5 is a cross-sectional view showing a second modification of the conductive particles.

  The conductive particles 41 shown in FIG. 5 have base material particles 22 and conductive portions 23 </ b> B disposed on the surface of the base material particles 22. The conductive portion 23B is a conductive layer. The conductive portion 23B includes a first conductive portion 23Bx disposed on the surface of the base particle 22 and a second conductive portion 23By disposed on the surface of the first conductive portion 23Bx.

  The conductive particles 41 have protrusions 41a on the conductive surface. The conductive particles 41 have protrusions 41a on the surface. The conductive portion 23B has a protrusion 23Ba on the surface (the outer surface of the conductive layer). The conductive particles 41 have a plurality of core substances 24 on the surface of the first conductive portion 23Bx. The second conductive portion 23By covers the first conductive portion 23Bx and the core substance 24. The substrate particles 22 and the core substance 24 are arranged with a space therebetween. A first conductive portion 23Bx exists between the base particle 22 and the core substance 24. By covering the core substance 24 with the second conductive portion 23By, the conductive portion 23B has a plurality of protrusions 23Ba on the surface. The surfaces of the conductive portion 23B and the second conductive portion 23By are raised by the core material 24, and a plurality of protrusions 23Ba are formed. There are a plurality of protrusions 41a and 23Ba.

  Like the conductive particles 41, the conductive portion 23B may have a multilayer structure. Further, in order to form the protrusions 41a and 23Ba, the core material 24 is disposed on the first conductive portion 23Bx of the inner layer, and the core material 24 and the first conductive portion 23Bx are separated by the second conductive portion 23By of the outer layer. It may be coated.

  Hereinafter, other details of the conductive particles, the conductive film, and the connection structure will be described.

(Conductive particles)
Examples of the substrate particles include resin particles, inorganic particles excluding metal particles, organic-inorganic hybrid particles, and metal particles. The substrate particles are preferably substrate particles excluding metal particles, and more preferably resin particles, inorganic particles excluding metal particles, or organic-inorganic hybrid particles.

  The substrate particles are preferably resin particles formed of a resin. When connecting the electrodes, the conductive particles are generally compressed after the conductive particles are arranged between the electrodes. When the substrate particles are resin particles, the conductive particles are easily deformed by compression, and the contact area between the conductive particles and the electrode is increased. For this reason, the conduction | electrical_connection reliability between electrodes becomes high.

  Various organic materials are suitably used as the material for the resin particles. Examples of the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; polyalkylene terephthalate and polysulfone. , Polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polysulfone, polyphenylene oxide, Polyacetal, polyimide, polyamideimide, polyether ether Ketones, polyether sulfones, and polymers such as obtained by a variety of polymerizable monomer having an ethylenically unsaturated group is polymerized with one or more thereof. In addition, by polymerizing one or more of various polymerizable monomers having an ethylenically unsaturated group, it is possible to design and synthesize resin particles having any compression property suitable for a conductive film. . Further, since the hardness of the base particles can be easily controlled within a suitable range, the material of the resin particles is a polymer obtained by polymerizing one or more polymerizable monomers having a plurality of ethylenically unsaturated groups. It is preferable that

  When the resin particles are obtained by polymerizing a monomer having an ethylenically unsaturated group, the monomer having the ethylenically unsaturated group may be a non-crosslinkable monomer or a crosslinkable monomer. And a polymer.

  Examples of the non-crosslinkable monomer include styrene monomers such as styrene and α-methylstyrene; carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, and maleic anhydride; (Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl ( Alkyl (meth) acrylates such as meth) acrylate and isobornyl (meth) acrylate; oxygen such as 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate and glycidyl (meth) acrylate (Meth) acrylates; nitrile-containing monomers such as (meth) acrylonitrile; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether; vinyl acids such as vinyl acetate, vinyl butyrate, vinyl laurate, vinyl stearate Esters; Unsaturated hydrocarbons such as ethylene, propylene, isoprene and butadiene; Halogen-containing monomers such as trifluoromethyl (meth) acrylate, pentafluoroethyl (meth) acrylate, vinyl chloride, vinyl fluoride and chlorostyrene Is mentioned.

  Examples of the crosslinkable monomer include tetramethylolmethane tetra (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and dipenta Erythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) Polyfunctional (meth) acrylates such as acrylate, (poly) tetramethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate; triallyl (iso) cyanure And silane-containing monomers such as triallyl trimellitate, divinylbenzene, diallyl phthalate, diallylacrylamide, diallyl ether, γ- (meth) acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, vinyltrimethoxysilane It is done.

  The resin particles can be obtained by polymerizing the polymerizable monomer having an ethylenically unsaturated group by a known method. Examples of this method include a method of suspension polymerization in the presence of a radical polymerization initiator, and a method of polymerization by swelling a monomer together with a radical polymerization initiator using non-crosslinked seed particles.

  In the case where the substrate particles are inorganic particles or organic-inorganic hybrid particles excluding metal particles, examples of the inorganic material that is a material of the substrate particles include silica and carbon black. The particles formed from the silica are not particularly limited. For example, after forming a crosslinked polymer particle by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups, firing may be performed as necessary. The particle | grains obtained by performing are mentioned. Examples of the organic / inorganic hybrid particles include organic / inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

  When the substrate particles are metal particles, examples of the metal that is a material of the metal particles include silver, copper, nickel, silicon, gold, and titanium. However, the substrate particles are preferably not metal particles.

  The average particle diameter of the substrate particles is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 1 μm or more, still more preferably 1.5 μm or more, particularly preferably 2 μm or more, preferably 1000 μm or less. More preferably, it is 500 μm or less, more preferably 300 μm or less, still more preferably 100 μm or less, still more preferably 50 μm or less, still more preferably 30 μm or less, particularly preferably 5 μm or less, and most preferably 3 μm or less. When the average particle diameter of the base particles is equal to or more than the above lower limit, the contact area between the conductive particles and the electrodes is increased, so that the conduction reliability between the electrodes is further increased and the conductive particles are connected via the conductive particles. The connection resistance between the electrodes is further reduced. Further, when the conductive portion is formed on the surface of the base particle by electroless plating, it becomes difficult to aggregate and the aggregated conductive particles are hardly formed. When the average particle diameter of the substrate particles is not more than the above upper limit, the conductive particles are easily compressed, the connection resistance between the electrodes is further reduced, and the interval between the electrodes is further narrowed.

  The average particle diameter of the substrate particles is particularly preferably 0.1 μm or more and 5 μm or less. When the average particle diameter of the substrate particles is in the range of 0.1 to 5 μm, even when the distance between the electrodes is small and the thickness of the conductive part is increased, small conductive particles can be obtained. From the viewpoint of obtaining even smaller conductive particles even if the distance between the electrodes is further reduced or the thickness of the conductive portion is increased, the average particle diameter of the base particles is preferably 0.5 μm. Above, more preferably 2 μm or more, preferably 3 μm or less.

  The average particle diameter is a number average particle diameter. The average particle diameter can be measured using, for example, a Coulter counter (manufactured by Beckman Coulter).

  The thickness of the conductive portion (when there are a plurality of conductive portions, the total thickness of the plurality of conductive portions) is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 20 nm or more, particularly preferably 50 nm or more, preferably Is 1000 nm or less, more preferably 800 nm or less, still more preferably 500 nm or less, particularly preferably 400 nm or less, and most preferably 300 nm or less. When the thickness of the conductive part is equal to or greater than the lower limit, the conductivity of the conductive particles is further improved. When the thickness of the conductive part is not more than the above upper limit, the difference in the coefficient of thermal expansion between the base particle and the conductive part becomes small, and the conductive part becomes difficult to peel from the base particle.

  Examples of a method for forming the conductive part on the surface of the substrate particle include a method for forming the conductive part by electroless plating and a method for forming the conductive part by electroplating.

  The conductive part preferably contains a metal. The metal that is the material of the conductive part is not particularly limited. Examples of the metal include gold, silver, copper, platinum, palladium, zinc, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium, molybdenum, tungsten and cadmium, and alloys thereof. Is mentioned. Further, tin-doped indium oxide (ITO) may be used as the metal. As for the said metal, only 1 type may be used and 2 or more types may be used together.

  The conductive particles have a plurality of protrusions on the conductive surface. Since the core substance is embedded in the conductive portion, protrusions can be easily formed on the outer surface of the conductive portion. An oxide film is often formed on the surface of the electrode connected by the conductive particles. When conductive particles having protrusions are used, the oxide film is effectively eliminated by the protrusions by placing the conductive particles between the electrodes and pressing them. For this reason, an electrode and electroconductive particle contact more reliably and the connection resistance between electrodes becomes still lower. Furthermore, the protrusion effectively eliminates the binder resin between the conductive particles and the electrode. For this reason, the conduction | electrical_connection reliability between electrodes becomes high.

  As a method for forming protrusions on the surface of the conductive particles, a method of forming a conductive portion by electroless plating after attaching a core substance to the surface of the base particles, and electroless plating on the surface of the base particles Examples include a method of forming a conductive part by, attaching a core substance, and further forming a conductive part by electroless plating. As another method for forming the protrusion, a first conductive part is formed on the surface of the base particle, and then a core substance is disposed on the first conductive part, and then the second conductive part. And a method of adding a core substance in the middle of forming a conductive part on the surface of the base particle.

  As a method of attaching the core substance to the surface of the base particle, for example, a core substance is added to the dispersion of the base particle, and the core substance is applied to the surface of the base particle by, for example, van der Waals force. Examples thereof include a method of accumulating and adhering, and a method of adding a core substance to a container containing base particles and attaching the core substance to the surface of the base particles by a mechanical action such as rotation of the container. Especially, since the quantity of the core substance to adhere is easy to control, the method of making a core substance accumulate and adhere on the surface of the base particle in a dispersion liquid is preferable.

  Examples of the material of the core substance include a conductive substance and a non-conductive substance. Examples of the conductive material include conductive non-metals such as metals, metal oxides, and graphite, and conductive polymers. Examples of the conductive polymer include polyacetylene. Examples of the nonconductive material include silica, alumina, and zirconia. Among them, metal is preferable because conductivity can be increased and connection resistance can be effectively reduced. The core substance is preferably metal particles.

  Examples of the metal include gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium, and cadmium, and tin-lead. Examples include alloys composed of two or more metals such as alloys, tin-copper alloys, tin-silver alloys, tin-lead-silver alloys, and tungsten carbide. Of these, nickel, copper, silver or gold is preferable. The metal that is the material of the core substance may be the same as or different from the metal that is the material of the conductive part. The material of the core substance preferably includes nickel. Examples of the metal oxide include alumina, silica and zirconia.

  The shape of the core material is not particularly limited. The shape of the core substance is preferably a lump. Examples of the core substance include a particulate lump, an agglomerate in which a plurality of fine particles are aggregated, and an irregular lump.

  The average diameter (average particle diameter) of the core substance is preferably 0.001 μm or more, more preferably 0.05 μm or more, preferably 0.9 μm or less, more preferably 0.2 μm or less. When the average diameter of the core substance is not less than the above lower limit and not more than the above upper limit, the connection resistance between the electrodes is effectively reduced.

  The “average diameter (average particle diameter)” of the core substance indicates a number average diameter (number average particle diameter). The average diameter of the core material is obtained by observing 50 arbitrary core materials with an electron microscope or an optical microscope and calculating an average value.

  The average height of the protrusions in the conductive particles is preferably 0.001 μm or more, more preferably 0.05 μm or more, still more preferably more than 0.1 μm, particularly preferably 0.125 μm or more, preferably 0.9 μm. Below, it is more preferably 0.3 μm or less, still more preferably 0.2 μm or less. When the average height of the protrusions is not less than the above lower limit and not more than the above upper limit, the connection resistance between the electrodes is effectively reduced. In particular, when the average height of the protrusions in the conductive particles is 0.125 μm or more, the arrangement accuracy of the conductive particles and the connection reliability between the electrodes are further improved. In particular, when the average height of the protrusions in the conductive particles is 0.3 μm or less, the arrangement accuracy of the conductive particles and the connection reliability between the electrodes are further improved.

  From the viewpoint of further suppressing the generation of voids and further improving the connection reliability between the electrodes, the average particle diameter of the conductive particles is 2 μm or more and 5 μm or less, and the average height of the protrusions in the conductive particles is Is preferably 50 nm or more and 500 nm or less.

(Conductive film)
The conductive film includes conductive particles and a binder resin. The conductive film is preferably an anisotropic conductive film. The anisotropic conductive film includes a conductive film for conducting between the upper and lower electrodes. The conductive film is preferably used for electrical connection between electrodes. The conductive film is preferably a conductive film for circuit connection.

  The binder resin is not particularly limited. In general, an insulating resin is used as the binder resin. Examples of the binder resin include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, and elastomers. As for the said binder resin, only 1 type may be used and 2 or more types may be used together.

  Examples of the vinyl resin include vinyl acetate resin, acrylic resin, and styrene resin. Examples of the thermoplastic resin include polyolefin resins, ethylene-vinyl acetate copolymers, and polyamide resins. Examples of the curable resin include an epoxy resin, a urethane resin, a polyimide resin, and an unsaturated polyester resin. The curable resin may be a room temperature curable resin, a thermosetting resin, a photocurable resin, or a moisture curable resin. The curable resin may be used in combination with a curing agent. Examples of the thermoplastic block copolymer include a styrene-butadiene-styrene block copolymer, a styrene-isoprene-styrene block copolymer, a hydrogenated product of a styrene-butadiene-styrene block copolymer, and a styrene-isoprene. -Hydrogenated product of a styrene block copolymer. Examples of the elastomer include styrene-butadiene copolymer rubber and acrylonitrile-styrene block copolymer rubber.

  In addition to the conductive particles and the binder resin, the conductive film includes, for example, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, and a light stabilizer. Various additives such as an agent, an ultraviolet absorber, a lubricant, an antistatic agent and a flame retardant may be contained.

  The content of the binder resin in 100% by weight of the conductive film is preferably 10% by weight or more, more preferably 30% by weight or more, still more preferably 50% by weight or more, and preferably 90.99% by weight or less. When the content of the binder resin is not less than the above lower limit and not more than the above upper limit, the conductive particles are efficiently arranged between the electrodes, and the conduction reliability between the electrodes is further enhanced. Said content shows content in the whole multilayer film, when a conductive film is a multilayer film.

  In 100% by weight of the conductive film, the content of the conductive particles is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, preferably 80% by weight or less, more preferably 40% by weight or less, More preferably, it is 20 weight% or less, Most preferably, it is 10 weight% or less. When the content of the conductive particles is not less than the above lower limit and not more than the above upper limit, the conduction reliability between the electrodes is further enhanced. Said content shows content in the whole multilayer film, when a conductive film is a multilayer film.

(Connection structure)
A connection structure can be obtained by connecting a connection object member using the conductive film according to the present invention.

  The connection structure includes a first connection target member, a second connection target member, and a connection part connecting the first and second connection target members, and the connection part is the conductive film described above. It is preferable that it is the connection structure formed by these.

  FIG. 6 is a cross-sectional view schematically showing an example of a connection structure using the conductive film 1 shown in FIG.

  The connection structure 51 shown in FIG. 6 includes a first connection target member 52, a second connection target member 53, and a connection portion 54 connecting the first and second connection target members 52 and 53. Prepare. The connection part 54 is formed of the conductive film 1. The connecting portion 54 is preferably formed by curing the conductive film 1.

  The first connection target member 52 has a plurality of first electrodes 52a on the surface (upper surface). The second connection target member 53 has a plurality of second electrodes 53a on the surface (lower surface). The first electrode 52 a and the second electrode 53 a are electrically connected by one or a plurality of conductive particles 21. Accordingly, the first and second connection target members 52 and 53 are electrically connected by the conductive particles 21.

  The manufacturing method of the connection structure is not particularly limited. As an example of the manufacturing method of a connection structure, after arrange | positioning the said electrically conductive film between the 1st connection object member and the 2nd connection object member, and obtaining a laminated body, it heats and pressurizes this laminated body. Methods and the like.

The pressure of the said pressurization is about 9.8 * 10 < ⁴ > -4.9 * 10 < ⁶ > Pa. The heating temperature is preferably about 100 to 220 ° C, more preferably about 120 to 220 ° C. The heating temperature is more preferably 180 ° C. or less, particularly preferably 160 ° C. or less, and most preferably 140 ° C. or less. When the temperature range of the heating is satisfied, the effect of the present invention is effectively achieved because the 10% K value of the conductive particles at 100 ° C. and the melt viscosity of the conductive film at 100 ° C. are within the above ranges. can get.

  Specific examples of the connection target member include electronic components such as semiconductor chips, capacitors, and diodes, and electronic components such as printed boards, flexible printed boards, glass epoxy boards, and glass boards. The connection target member is preferably an electronic component. The conductive particles are preferably used for electrical connection of electrodes in an electronic component.

  Examples of the electrode provided on the connection target member include metal electrodes such as a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a silver electrode, a molybdenum electrode, and a tungsten electrode. When the connection object member is a flexible printed board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, or a copper electrode. When the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, or a tungsten electrode. In addition, when the said electrode is an aluminum electrode, the electrode formed only with aluminum may be sufficient and the electrode by which the aluminum layer was laminated | stacked on the surface of the metal oxide layer may be sufficient. Examples of the material for the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al, and Ga.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited only to the following examples.

Example 1
(1) Conductive Particles Conductive particles having divinylbenzene resin particles (average particle diameter of 3 μm) coated with a nickel plating layer (thickness 0.1 μm) and having a plurality of protrusions on the surface of the nickel plating layer. Prepared.

The average height of the protrusions in this conductive particle was 150 nm. Of the total surface area of 100% of the conductive particles, the surface area of the conductive particles where the protrusions are present (protrusion parts) is 62%, and the surface area of the conductive particles where the protrusions are not present (unprojected parts) is 38%. (Refer to the evaluation column below for the evaluation method of the surface area). The 10% K value of the conductive particles at 100 ° C. was 5320 N / mm ² .

(2) Production of conductive film 50 parts by weight of phenoxy resin (“PKHH” manufactured by InChem), 25 parts by weight of phenol novolac type epoxy resin (“TD-2106” manufactured by DIC) which is a thermosetting compound, and thermal cation 1 part by weight of a curing agent (“SI-60” manufactured by Sanshin Chemical Co., Ltd.), 1 part by weight of a silane coupling agent, and 10 parts by weight of the conductive particles were dispersed in toluene, and the solid content was 40% by weight. A resin composition was prepared. This resin composition was coated on polyethylene terephthalate with a coater, and the solvent was dried to obtain an anisotropic conductive film having a thickness of 18 μm.

  The melt viscosity at 100 ° C. of the obtained anisotropic conductive film was 900 Pa · s. The melt viscosity was measured using a viscoelasticity measuring device “ARES-G2” manufactured by TA Instruments under the conditions of a temperature rising rate of 5 ° C./min and 1 Hz, and a melt viscosity at 100 ° C. was calculated.

(3) Production of Connection Structure A transparent glass substrate (first connection target member) having a multilayer electrode pattern of Ti—Al—Ti with L / S of 15 μm / 15 μm on the upper surface was prepared. In addition, a semiconductor chip (second connection target member) having a nickel electrode pattern with a L / S of 15 μm / 15 μm on the lower surface was prepared.

  The obtained anisotropic conductive film was temporarily pressure-bonded and attached to the chip mounting portion on the transparent glass substrate using a temporary pressure bonding machine. Next, after laminating the semiconductor chip so that the electrodes face each other, a pressure heating head is placed on the upper surface of the semiconductor chip while adjusting the temperature of the head so that the temperature of the anisotropic conductive film becomes 130 ° C. Then, thermocompression bonding was performed for 10 seconds under a pressure of 3 MPa, and the binder resin in the anisotropic conductive film was cured to obtain a connection structure.

(Example 2)
(1) Conductive particles The conductive particles of Example 1 were prepared.

(2) Production of conductive film 50 parts by weight of phenoxy resin (“PKHH” manufactured by InChem), 25 parts by weight of phenol novolac type epoxy resin (“TD-2106” manufactured by DIC) which is a thermosetting compound, and thermal cation 1 part by weight of a curing agent (“SI-60” manufactured by Sanshin Chemical Co., Ltd.), 1 part by weight of a silane coupling agent, and 10 parts by weight of the conductive particles were dispersed in toluene, and the solid content was 40% by weight. A resin composition was prepared. The resin composition was coated on polyethylene terephthalate with a coater, and the solvent was dried to obtain a first layer (ACF) having a thickness of 8 μm.

  Next, 50 parts by weight of a phenoxy resin (“PKHC” manufactured by InChem), 25 parts by weight of a phenol novolac type epoxy resin (“TD-2106” manufactured by DIC), which is a thermosetting compound, and a thermal cation curing agent (three Shinji Chemical Co., Ltd. “SI-60”) 1 part by weight and silane coupling agent 1 part by weight were dispersed in toluene to prepare a resin composition having a solid content of 40% by weight. The resin composition was applied onto polyethylene terephthalate with a coater, and the solvent was dried to obtain a second layer (NCF) having a thickness of 12 μm.

  The obtained first layer (ACF) and the obtained second layer (NCF) were laminated using a laminator to obtain an anisotropic conductive film having a thickness of 20 μm.

  The melt viscosity at 100 ° C. of the obtained anisotropic conductive film was 800 Pa · s.

(3) Production of Connection Structure A transparent glass substrate (first connection target member) having a multilayer electrode pattern of Ti—Al—Ti with L / S of 15 μm / 15 μm on the upper surface was prepared. In addition, a semiconductor chip (second connection target member) having a nickel electrode pattern with a L / S of 15 μm / 15 μm on the lower surface was prepared.

  The obtained anisotropic conductive film was temporarily pressure-bonded and attached to the chip mounting portion on the transparent glass substrate using a temporary pressure bonding machine. The anisotropic conductive film was disposed so that the first layer (ACF) was on the transparent glass substrate side. Next, after laminating the semiconductor chip so that the electrodes face each other, a pressure heating head is placed on the upper surface of the semiconductor chip while adjusting the temperature of the head so that the temperature of the anisotropic conductive film becomes 130 ° C. Then, thermocompression bonding was performed for 10 seconds under a pressure of 3 MPa, and the binder resin in the anisotropic conductive film was cured to obtain a connection structure.

(Example 3)
The average height of the protrusions in the conductive particles is 400 nm, and the total surface area of the conductive particles is 100%, the surface area of the conductive particles with the protrusions is 90%, and the conductive particles have no protrusions. A connection structure was prepared in the same manner as in Example 1 except that the surface area of the film was 10%.

Example 4
The average height of the protrusions in the conductive particles is 100 nm, and the surface area of the conductive particles in the conductive particles is 55% in the total surface area of 100% of the conductive particles, and the conductive particles have no protrusions in the surface area. A connection structure was produced in the same manner as in Example 1 except that the surface area of the film was 45%.

(Example 5)
A connection structure was prepared in the same manner as in Example 1 except that the divinylbenzene resin particles were changed to copolymer resin particles of 70% by weight divinylbenzene and 30% by weight acrylonitrile. The 10% K value of this conductive particle at 100 ° C. was 9730 N / mm ² .

(Example 6)
A connection structure was produced in the same manner as in Example 1 except that the divinylbenzene resin particles were changed to copolymer resin particles of 50% by weight divinylbenzene and 50% by weight 1,4-butanediol diacrylate. The 10% K value of this conductive particle at 100 ° C. was 3250 N / mm ² .

(Example 7)
Other than changing 50 parts by weight of phenoxy resin (“PKHH” manufactured by InChem) to a mixture of 10 parts by weight of phenoxy resin (“PKHH” manufactured by InChem) and 40 parts by weight of phenoxy resin (“PKHC” manufactured by InChem) Obtained an anisotropic conductive film in the same manner as in Example 1 to prepare a connection structure. The melt viscosity at 100 ° C. of the obtained anisotropic conductive film was 350 Pa · s.

(Example 8)
A connection structure was produced in the same manner as in Example 1 except that the conductive particles used in Example 1 were coated with insulating particles on the surface.

The insulating particles used here are organic polymer insulating particles containing methyl methacrylate as a main component and having P—OH groups and glycidyl groups on the surface. The average particle size of the insulating particles was 300 nm. The 10% K value of the conductive particles at 100 ° C. was 5320 N / mm ² .

Example 9
The surface of the divinylbenzene resin particles (average particle diameter 2 μm) was covered with a nickel plating layer (thickness 0.08 μm), and conductive particles having a plurality of protrusions on the surface of the nickel plating layer were prepared.

  The average height of the protrusions in this conductive particle was 100 nm. Of the total surface area of 100% of the conductive particles, the surface area of the conductive particles with the protrusions was 52%, and the surface area of the conductive particles without the protrusions was 48%.

  A connection structure was produced in the same manner as in Example 1 except that the above conductive particles were used.

(Example 10)
A connection structure was prepared in the same manner as in Example 1 except that the temperature of the head was adjusted so that the temperature of the anisotropic conductive paste layer during thermocompression was 150 ° C., and thermocompression was performed.

(Comparative Example 1)
The average height of the protrusions in the conductive particles is 150 nm, and the total surface area of the conductive particles is 100%, the surface area of the conductive particles with the protrusions is 45%, and the conductive particles have no protrusions. A connection structure was produced in the same manner as in Example 1 except that the surface area of the film was 55%.

(Comparative Example 2)
The average height of the protrusions in the conductive particles is 150 nm, and the total surface area of the conductive particles is 100%, the surface area of the conductive particles with the protrusions is 97%, and the conductive particles have no protrusions. A connection structure was produced in the same manner as in Example 1 except that the surface area of the material was 3%.

(Comparative Example 3)
A connection structure was produced in the same manner as in Example 1 except that the divinylbenzene resin particles were changed to copolymer resin particles of 60% by weight divinylbenzene and 40% by weight acrylonitrile. The 10% K value of this conductive particle at 100 ° C. was 10590 N / mm ² .

(Comparative Example 4)
A connection structure was prepared in the same manner as in Example 1 except that the divinylbenzene resin particles were changed to copolymer resin particles of 40% by weight divinylbenzene and 60% by weight 1,4-butanediol diacrylate. The 10% K value of this conductive particle at 100 ° C. was 2860 N / mm ² .

(Comparative Example 5)
An anisotropic conductive film was obtained in the same manner as in Example 1 except that 50 parts by weight of phenoxy resin (“PKHH” manufactured by InChem) was changed to 50 parts by weight of phenoxy resin (“PKHC” manufactured by InChem). A connection structure was produced. The melt viscosity at 100 ° C. of the obtained anisotropic conductive film was 290 Pa · s.

(Evaluation)
(1) Measurement of protrusion density Using FE-SEM (“S-4000” manufactured by Hitachi High-Tech Corporation), the number of sheets capable of measuring 50 particles at 6000 times was photographed.

  The photographed image is binarized by image processing software, and the surface area of the protruding part (the part with the protrusion and the protruding part) and the non-protruding part (the part without the protrusion and the protruding part) for one particle ) And the surface area.

(2) Presence / absence of voids The obtained connection structure is observed with an optical microscope from the transparent substrate side to observe between 100 wirings, and by counting the number of wirings with voids, the presence / absence of voids. Evaluated. The presence or absence of voids was determined according to the following criteria.

[Criteria for the presence or absence of voids]
○○: 0 between wires with voids ○: 1 or more and less than 3 between wires with voids Δ: 3 or more between wires with voids and less than 10 ×: 10 between wires with voids More than books

(3) Arrangement accuracy of conductive particles on electrode In the obtained connection structure, conductive particles contained in a connection portion formed of a conductive material were confirmed. The ratio (%) of the number of the conductive particles arranged on the electrode and the conductive particles arranged between the electrodes was evaluated. The arrangement accuracy of the conductive particles on the electrode was determined according to the following criteria.

[Judgment criteria for placement accuracy of conductive particles on electrode]
◯: Ratio of the number of conductive particles arranged on the electrode is 70% or more ○: Ratio of the number of conductive particles arranged on the electrode is 60% or more and less than 70% Δ: On the electrode Ratio of the number of conductive particles arranged is 50% or more and less than 60% ×: Ratio of the number of conductive particles arranged on the electrode is less than 50%

(4) Connection reliability between electrodes In the obtained connection structure (n = 15), the connection resistance between the upper and lower 20 electrodes is measured by the 4-terminal method, and the average value of the connection resistance is calculated. did. Note that the connection resistance can be obtained by measuring the voltage when a constant current is passed from the relationship of voltage = current × resistance. Then, after holding a connection structure for 100 hours in a 85 degreeC85% high temperature high humidity tank, the average value of connection resistance was computed by performing the same measurement. The connection reliability was evaluated by calculating the connection reliability increase rate by the following formula. Connection reliability The connection reliability between the electrodes was determined according to the following criteria.

  Connection reliability increase rate = (connection resistance after holding at high temperature and high humidity) / (initial connection resistance)

[Connection reliability criteria]
○○: Connection resistance increase rate is 2 times or less ○: Connection resistance increase rate exceeds 2 times and 5 times or less △: Connection resistance increase rate exceeds 5 times and 10 times or less ×: Connection resistance increase The rate exceeds 10 times

  The results are shown in Table 1 below.

DESCRIPTION OF SYMBOLS 1,1A ... Conductive film 2 ... 1st layer 3 ... 2nd layer 11, 11A, 11B ... Binder resin 21 ... Conductive particle 21a ... Protrusion 22 ... Base particle 23, 23A, 23B ... Conductive part 23a, 23Aa , 23Ba ... projection 23Bx ... first conductive part 23By ... second conductive part 24 ... core material 31, 41 ... conductive particles 31a, 41a ... projection 51 ... connection structure 52 ... first connection target member 52a ... first 1 electrode 53... Second connection target member 53 a... Second electrode 54.

Claims (7)

Containing conductive particles and a binder resin,
The conductive particles have a plurality of protrusions on a conductive surface;
Of the total surface area of 100% of the conductive particles, the surface area of the conductive particles where the protrusions are present is 50% or more and 95% or less, and the surface area of the conductive particles where the protrusions are not present is 5%. Above, 50% or less,
The compressive modulus of the conductive particles when compressed 10% at 100 ° C. is 3000N / mm ² or more and 10000 N / mm ² or less,
The conductive film whose melt viscosity in 100 degreeC is 300 Pa.s or more and 1000 Pa.s or less. The average particle diameter of the conductive particles is 2 μm or more and 5 μm or less,
The conductive film according to claim 1, wherein an average height of the protrusions in the conductive particles is 50 nm or more and 500 nm or less. It is a single layer film containing the conductive particles and the binder resin, or is laminated on one side of the first layer and the first layer containing the conductive particles and the binder resin. And a multilayer film having a second layer not containing the conductive particles and containing the binder resin,
In the case of the single layer film, the thickness of the single layer film is not less than 5 times and not more than 7 times the average particle diameter of the conductive particles,
3. The conductive film according to claim 1, wherein in the case of the multilayer film, the thickness of the multilayer film is 5 to 8 times the average particle diameter of the conductive particles.   In the case of the multilayer film, the thickness of the first layer including the conductive particles is not less than 2 times and not more than 4 times the average particle diameter of the conductive particles, and includes the conductive particles. The conductive film according to claim 3, wherein the thickness of the second layer that is not present is 1 to 3 times the thickness of the first layer.   The conductive film of any one of Claims 1-3 which is a single layer film containing the said electroconductive particle and the said binder resin.   A first layer containing the conductive particles and the binder resin; and a second layer laminated on one side of the first layer and not containing the conductive particles and containing the binder resin. The electrically conductive film of any one of Claims 1-4 which is a multilayer film which has. A first connection object member having a first electrode on its surface;
A second connection target member having a second electrode on its surface;
A connection portion connecting the first connection target member and the second connection target member;
The connection part is formed of the conductive film according to any one of claims 1 to 6,
A connection structure in which the first electrode and the second electrode are electrically connected by the conductive particles.

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