JP2016062879A - Anisotropic conductive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: an anisotropic conductive material that gives an excellent continuity at the initial and after the reliability test; a connection structure; a touch panel device; and a manufacturing process for connection structure.SOLUTION: Provided is an anisotropic conductive material containing a binder resin 31, and a conductive particle 33 contained in the binder resin 31 and having a compressive modulus at 30% deformation of 30 MPa or more and 120 MPa or less, and in which the conductive particle 33 has a projecting portion P on the surface thereof; and thereby, for example, even when a deformable plastic substrate is used as a first supporting substrate 12, the occurrence of a crack in terminals 11, 22 can be suppressed, and at the initial and after the reliability test, an excellent continuity can be obtained.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an anisotropic conductive material used for connecting electronic components, a connection structure, a touch panel device, and a method for manufacturing the connection structure.

  In recent years, plastic substrates such as polyethylene terephthalate (PET) and polycycloolefin have been used for substrates such as touch panel sensors. As the wiring made of ITO or the like applied to these plastic substrates, a thin wiring of 1 μm or less tends to be used for the purpose of invisibility and cost reduction.

  When an electrical connection portion is provided on such a wiring board using a normal ACF (Anisotropic Conductive Film), the conductive particles dispersed and contained in the ACF are caused to adhere to the terminal and the lower part of the terminal by the pressure applied by pressure bonding. The plastic substrate may be deformed and a crack may be generated in the terminal portion. When a crack occurs in the terminal portion, the conduction resistance may increase after a reliability test exposed to a stress condition such as a predetermined temperature and humidity.

  FIG. 3 shows an example of a conventional connection structure. The connection structure shown in FIG. 3 includes a first electronic component 110 including a first support substrate 112 and a terminal 111 provided on the main surface thereof, a second support substrate 121 and a terminal provided on the main surface thereof. The second electronic component 120 including 122 is bonded by pressure bonding via the ACF 130. The ACF 130 includes a binder resin 131 and conductive particles 133 dispersed and contained in the binder resin 131. The conductive particle 133 has a metal layer 137 on the surface of the core particle 136.

  When a highly elastic type that is difficult to be deformed with respect to pressure is used as the conductive particle 133, it is suitable for ensuring electrical conductivity between electronic components. However, if the core particle 136 is too hard, the first When the support substrate 112 is a plastic substrate, the pressure at the time of pressure bonding cannot be absorbed, and a crack may occur in a part of the terminal 111. For this reason, attempts have been made to prevent cracks by defining the elastic modulus of conductive particles to a predetermined condition (for example, Patent Document 1).

JP 2001-332136 A

  In order to avoid cracks in the terminal part, the conductive particles in the ACF should be made of a low elastic type that is sufficiently deformable against pressure, and the pressure on the terminal part is reduced by deformation of the conductive particles. Can be considered. However, if the conductive particles are made too low in elasticity, the contact between the conductive particles and the terminals may not be sufficient, and the initial conduction resistance may increase, and it is not necessary to simply reduce the elasticity.

  FIG. 4 shows an example of a connection structure using low-elasticity conductive particles. In the connection structure shown in FIG. 4, the description of the same configuration as that in FIG. 3 is omitted. In the example shown in FIG. 4, a soft material is used as the core particle 136, but because it is too soft, it is deformed too much at the time of crimping, and sufficient conduction between the terminals 111 and 122 cannot be obtained.

  In view of the circumstances as described above, the present invention provides an anisotropic conductive material, a connection structure, a touch panel device, and a method for manufacturing the connection structure that provide excellent electrical conductivity after the initial and reliability tests.

  In order to solve the above-described problems, an anisotropic conductive material according to the present invention includes a binder resin and conductive particles that are contained in the binder resin and have a compressive elastic modulus at 30% deformation of 30 MPa to 120 MPa. And the conductive particles have protrusions on the surface.

  In addition, a connection structure according to the present invention includes a first electronic component having a terminal formed on a first support substrate, a second electronic component having a terminal formed on a second support substrate, An anisotropic conductive film made of a cured product of an anisotropic conductive material containing conductive particles that connect the terminal of the first electronic component and the terminal of the second electronic component; The material contains a binder resin and conductive particles that are contained in the binder resin and have a compression elastic modulus of 30 MPa or more and 120 MPa or less at 30% deformation, and the conductive particles have protrusions on the surface. It is characterized by that.

  In addition, a touch panel device according to the present invention includes the above-described connection structure.

  The connection structure manufacturing method according to the present invention includes a first electronic component having a terminal formed on a first support substrate and a second electronic component having a terminal formed on a second support substrate. A binder resin and conductive particles that are contained in the binder resin and have a compression elastic modulus at 30% deformation of 30 MPa or more and 120 MPa or less, and the conductive particles have protrusions on the surface. A bonded structure is obtained by pressure bonding with an anisotropic conductive adhesive film interposed therebetween, and curing the anisotropic adhesive film.

  According to the present invention, the compressive elastic modulus at 30% deformation is 30 MPa or more and 120 MPa or less, and conductive particles having protrusions on the surface are used. After the property test, excellent conductivity can be obtained.

FIG. 1 is a diagram schematically showing a partial cross section of a connection structure using an anisotropic conductive material. FIG. 2 is a cross-sectional view showing an example of conductive particles having protrusions. FIG. 3 is a diagram schematically showing a partial cross section of a connection structure using a conventional anisotropic conductive material. FIG. 4 is a diagram schematically showing a partial cross section of another example of a connection structure using a conventional anisotropic conductive material.

Hereinafter, embodiments of the present invention will be described in detail in the following order with reference to the drawings.
1. 1. An anisotropic conductive material and connection structure Example

<1. Anisotropic Conductive Material and Connection Structure>
FIG. 1 is a diagram schematically showing a partial cross section of a connection structure using an anisotropic conductive material. As shown in FIG. 1, the connection structure includes a first electronic component 10 in which a terminal 11 is formed on a first support substrate 12, and a second in which a terminal 22 is formed on a second support substrate 21. Anisotropic conductive material comprising a cured product of an anisotropic conductive material containing conductive particles 33 connecting the electronic component 20 of the first electronic component 10 and the terminal 11 of the first electronic component 10 and the terminal 22 of the second electronic component 20. A film 30.

  In FIG. 1, the conductive particles 33 are formed by coating a metal layer 37 so as to cover the entire surface of the core particles 36, and are slightly deformed due to pressure during pressure bonding. Although it depends on the conditions such as pressure bonding, in general, in connection structures such as touch panels, there are many cases where conductive particles are deformed by about 30% as a result of pressure bonding. For this reason, in specifying the hardness of the conductive particles, using the compressive elastic modulus under a specific condition of the compressive elastic modulus at the time of 30% deformation as an index means that an electronic component is electrically connected using an anisotropic conductive material. It is an excellent index for showing conductive particles in a state of being connected well.

  That is, the anisotropic conductive material according to the present embodiment contains a binder resin and conductive particles 33 that are contained in the binder resin and have a compression elastic modulus at 30% deformation of 30 MPa to 120 MPa. The conductive particles 33 have protrusions P on the surface. Thereby, for example, even when a plastic substrate that is easily deformed is used as the first support substrate 12, it is possible to suppress the occurrence of cracks in the terminals 12 and 22, and excellent conduction after the initial and reliability tests. Sex can be obtained. Here, the plus chip substrate refers to a thermoplastic flexible substrate having both transparency and electrical characteristics.

  The lower limit value of the compression elastic modulus at the time of 30% deformation of the conductive particles is preferably 30 MPa or more, more preferably 45 MPa or more. By setting the compression elastic modulus to be equal to or higher than such a lower limit value, it is possible to prevent the resistance value from increasing due to the conductive particles being too soft. Moreover, the upper limit of the compression elastic modulus at the time of 30% deformation of the conductive particles is preferably 120 MPa or less, more preferably 110 MPa or less. By setting the compression elastic modulus to be equal to or lower than such an upper limit value, it is possible to suppress occurrence of cracks in the terminal portion in anisotropic conductive connection such as electronic parts.

The compression elastic modulus at the time of 30% deformation of the conductive particles can be determined, for example, as follows. Using a micro-compression tester, the conductive particles are compressed by 30% in diameter ratio, and the load value (compression deformation load value) at that time is obtained. The compression elastic modulus St (unit: MPa) can be calculated from the compressive deformation load value P (unit: mN) and the particle diameter d (unit: μm) by the following formula 1.
St = 2.8P / (π · d ² ) (Formula 1)

  The lower limit of the area ratio of the protrusions to the surface area in the absence of the conductive particle protrusions is preferably 5% or more, more preferably 20% or more. By setting the area ratio of the protrusions to such a lower limit, contact between the protrusions and the terminals is sufficiently performed, and good initial conductivity can be obtained. In addition, the upper limit of the area of the protruding portion in the surface area when there is no protruding portion of conductive particles is preferably 110% or less, more preferably 95% or less. By setting the area of the protrusion within such a range, the pressure applied to each protrusion is appropriate, and therefore excellent electrical conductivity can be obtained after the initial and reliability tests. That is, the area ratio of the protrusions to the surface area in the absence of the conductive particle protrusions is preferably 20% or more and 95% or less.

  Note that the area of the protrusions may exceed 100% because there are also particles that are formed on the protrusions so that the protrusions are formed. This is because of the calculation. Moreover, the area ratio of the protrusion part which occupies the surface area when there is no protrusion part of the conductive particles can be performed by analysis of an image obtained by SEM observation.

  It is preferable that the protrusion part of electroconductive particle is comprised from 1 or more types selected from the group which consists of nickel, palladium, and titanium. Since the protrusion is made of a metal having a relatively high hardness, even if the compressive elastic modulus of the conductive particles is relatively low, the protrusion bites into the terminal, so that good conductivity can be obtained. Further, the surface of these relatively hard metals may be plated with gold to improve conductivity. Here, the hardness means a Vickers hardness defined in JIS Z 2244.

  FIG. 2 is a cross-sectional view showing an example of conductive particles having protrusions. As shown in FIG. 2, the conductive particles 30 include a core particle 36, a first metal layer 38 that covers the core particle 36, fine particles 40 attached to the first metal layer, and a first metal layer. 38 and a second metal layer 39 covering the fine particles 40.

  As the core particles 36, resin particles are preferably used in order to make the compression elastic modulus of the conductive particles within the aforementioned range. Examples of the resin for forming the core particles include an epoxy resin, a phenol resin, an acrylic resin, an acrylonitrile / styrene (AS) resin, a benzoguanamine resin, a divinylbenzene resin, a styrene resin, and a copolymer resin thereof. Can be mentioned.

  The first metal layer 38 preferably contains nickel, and the second metal layer 39 preferably contains gold. Moreover, it is preferable that the fine particles 40 serving as protrusions are composed of one or more selected from the group consisting of nickel, palladium, titanium, and metal oxide. By being composed of a metal or metal oxide having a relatively high hardness, even if the compressive elastic modulus of the conductive particles is relatively low, the projecting portion bites into the terminal, so that good conductivity can be obtained.

  In the conductive particles shown in FIG. 2, the core particle 36 is depicted as a single body, but may be composed of a plurality of materials, or the core particle itself may have a multilayer structure. Further, the number of layers of the metal layer 37 is not particularly limited, and may be a multilayer structure other than that shown in FIG.

  The average particle diameter (D50) of the conductive particles is preferably 2 μm or more and 30 μm or less, and more preferably 4 μm or more and 20 μm or less. If the average particle size of the conductive particles is too small, anisotropic connection becomes difficult, and if the average particle size of the conductive particles is too large, the imprint of the conductive particles may be noticeable.

  The binder resin is not particularly limited, but a radical curable type capable of low temperature curing is preferably used. The radical curable binder resin contains a film-forming resin, a radical curable resin, and a radical polymerization initiator.

  Examples of the film forming resin include phenoxy resin, urethane resin, polyester resin, styrene isoprene resin, and nitrile butadiene resin.

  Examples of the radical curable resin include epoxy (meth) acrylates, urethane (meth) acrylates, (meth) acrylate oligomers, and the like. These may be used alone or in combination of two or more. May be used in combination.

  Examples of the thermal radical polymerization initiator include peroxides and azo compounds. Examples of peroxides include diacyl peroxide compounds, peroxy ester compounds, hydroperoxide compounds, peroxydicarbonate compounds, peroxyketal compounds, dialkyl peroxide compounds, and ketone peroxide compounds. Examples of the radical photopolymerization initiator include alkylphenone photopolymerization initiators, acylphosphine oxide photopolymerization initiators, titanocene polymerization initiators, and oxime ester photopolymerization initiators.

  Further, the binder resin may be appropriately mixed with other components such as a silane coupling agent, an inorganic filler, an elastomer such as acrylic rubber, and a pigment such as carbon black depending on the purpose.

  In addition, the shape of the anisotropic conductive material is not particularly limited, but it is preferable to form an anisotropic conductive film by forming it into a film shape.

  Next, the manufacturing method of the connection structure using the above-mentioned anisotropic conductive material will be described with reference to FIG. In the manufacturing method of the connection structure according to the present embodiment, the first electronic component 10 in which the terminal 11 is formed on the first support substrate 12 and the terminal 22 on the second support substrate 21 are formed. The second electronic component includes a binder resin 31 and conductive particles 33 that are contained in the binder resin 31 and have a compression elastic modulus at 30% deformation of 30 MPa or more and 120 MPa or less. Then, an anisotropic conductive adhesive film having protrusions P on the surface is interposed and pressure bonded, and the anisotropic adhesive film is cured to obtain a connection structure.

  The first electronic component 10 and the second electronic component 22 can be appropriately selected according to the purpose, but the elastic modulus of at least one of the first support substrate 12 and the second support substrate 22 is 5.5 GPa. The following electronic components are preferably used. Examples of the support substrate having an elastic modulus of 5.5 GPa or less include plus-chip substrates such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), and polycycloolefin. As the plastic substrate, polycycloolefin is preferably used from the viewpoint of transparency, low dielectric constant, low dielectric loss tangent, etc., and PET is preferably used from the viewpoint of price superiority in light of performance.

  Examples of the first electronic component include a plastic substrate for touch panel use, LCD (Liquid Crystal Display) panel use, and the like. In addition, examples of the second circuit member include a flexible printed circuit (FPC) such as COF (Chip On Film), a tape carrier package (TCP) substrate, and an integrated circuit (IC). In the form of the touch panel, for example, as the first support substrate 12, a substrate having a transmittance of 80% or more with respect to visible light can be used, and a substrate having a transmittance of 95% or more is preferably used. be able to.

<2. Example>
Examples of the present invention will be described below. In this example, conductive particles having a desired compressive elastic modulus were prepared and added to a binder resin to prepare an anisotropic conductive film. And the base material and FPC (Flexible Printed Circuits) were connected using the anisotropic conductive film, and the resistance value after an initial stage and a reliability test was measured. The present invention is not limited to these examples.

[Creation of conductive particles]
The conductive particles include a core particle, a first metal layer covering the core particle, fine particles attached to the first metal layer, and a second metal layer covering the first metal layer and the fine particles. The thing which has was produced. First, plastic core particles having an average particle diameter of 10 μm made of a copolymer of divinylbenzene and acrylic acid were prepared as core particles. The plastic core particles were prepared so that the degree of cross-linking was adjusted and a predetermined compression modulus was obtained.

  Next, after the nickel plating as the first metal layer is processed by electroless plating on the surface of the plastic core particles, the fine particles to be projections are attached, and then the second metal layer is further processed by electroless gold plating. The electroconductive particle which has a projection part was produced. The size of the protrusion was determined by analyzing an image obtained by SEM (Scanning Electron Microscope), and was about 0.1 μm to 1.0 μm, with an average of 0.5 μm.

  In addition, the electroconductive particle which does not have a projection part on the surface was produced except the process of attaching the microparticles | fine-particles for forming a projection part from the above.

[Measurement of occupation area ratio of protrusions of conductive particles]
The area occupied by the protrusions provided on the surface of the conductive particles was determined by analyzing an image obtained by SEM. The ratio of the area occupied by the protrusions was obtained as a percentage (%) by dividing the integrated value of the surface area of the protrusions by the value of the surface area of the same particle diameter without the protrusions on the surface. In addition, in the following test results, there are cases in which the proportion of the area occupied by the protrusions exceeds 100%. However, this is because particles that are formed on the protrusions so that the protrusions are formed exist and overlap. This is because the calculation is also performed for the protrusions that are present.

[Measurement of compression modulus of conductive particles]
The compression elastic modulus at 30% deformation of the conductive particles was determined as follows using a micro compression tester (MCT-W201, manufactured by Shimadzu Corporation). The conductive particles were compressed 30% with a smooth end face of a diamond cylinder having a diameter of 50 μm at a compression speed of 0.331 mN / sec, and the load value (compression deformation load value) at that time was determined. The compression elastic modulus St (unit: MPa) was calculated from the compression deformation load value P (unit: mN) and the particle diameter d (unit: μm) by the following formula 1.
St = 2.8P / (π · d ² ) (Formula 1)

[Production of ACF]
A binder resin having the following composition was prepared.

  2 parts by mass of conductive particles are added to the binder resin as a base material and stirred to sufficiently disperse the conductive particles in the binder resin base material, and then formed into a film shape to have a thickness of 25 μm and a width of 2. A 0 mm ACF was obtained.

[Production of connection structure]
As a base film, PET film (elastic modulus: 5.3 GPa, product name: PET-01-BU, manufactured by Mitsui Chemicals, Inc.), cycloolefin copolymer film (elastic modulus: 2.6 GPa, product name: ARTON D4540, JSR) and a polyimide film (elastic modulus: 6.9 GPa, product name: Upilex 75S, Ube Industries, Ltd.) were prepared. An ITO wiring pattern was formed on the surface of each substrate film having a thickness of 125 μm to prepare a first electronic component.

  A second electronic component (FPC) having a wiring pattern formed on a polyimide film surface with a copper wire plated with Ni / Au was prepared. The wiring height of the second electronic component was 25 μm, and the pitch was 400 μm (L / S = 200/200).

  The first electronic component and the second electronic component are arranged so that the respective terminals face each other, and the ACF is sandwiched between the two electronic components and crimped to form an electrical connection portion, whereby a bonded structure is obtained. It was. The pressure bonding was performed under the conditions of 150 ° C. and 1 MPa / 5 seconds.

[Measurement and evaluation of resistance value]
The initial resistance value (R1) of the bonded structure was measured using a digital multimeter (trade name: Digital Multimeter 7561, manufactured by Yokogawa Electric Corporation). The initial resistance was evaluated according to the following criteria.
◎: 0.3Ω or less ○: Greater than 0.3Ω, 0.5Ω or less ×: Greater than 0.5

Further, the bonded structure was allowed to stand for 500 hours under the conditions of 85 ° C. and 85% RH, and then the resistance value was measured to obtain the resistance value (R2) after the reliability test. The reliability was evaluated by obtaining a value (ΔR) obtained by subtracting the initial resistance value (R1) from the resistance value (R2) after the reliability test and comparing ΔR with the following criteria.
◎: 0.5Ω or less ○: Greater than 0.5Ω, 1.0Ω or less ×: Greater than 1.0Ω

  In addition, the comprehensive judgment was made by evaluating the initial resistance or the poorer reliability.

<Comparative Example 1>
As shown in Table 2, the first electronic component having a base film made of a PET film having an elastic modulus of 5.3 GPa was used. The electroconductive particle used what does not have a projection part on the surface. The compression elastic modulus at the time of 30% deformation of the conductive particles was 32 MPa. Using the anisotropic conductive film to which the conductive particles were added, the first electronic component and the second electronic component were connected to obtain a connection structure. The initial resistance value (R1) of the connection structure was 0.55Ω, and the evaluation of the initial resistance was x. The resistance value (R2) after the reliability test was 1.21Ω, ΔR was 0.66Ω, and the reliability was evaluated as ◯. Therefore, the comprehensive judgment was x.

<Comparative Example 2>
As shown in Table 2, a connection structure was obtained in the same manner as in Comparative Example 1 except that conductive particles having a compression elastic modulus at 30% deformation of 197 MPa were used. The initial resistance value (R1) of the connection structure was 0.97Ω, and the evaluation of the initial resistance was x. The resistance value (R2) after the reliability test was 2.53Ω, ΔR was 1.56Ω, and the reliability was evaluated as x. Therefore, the comprehensive judgment was x.

<Conventional example>
As shown in Table 2, a connection structure was obtained in the same manner as in Comparative Example 2 except that the first electronic component using a polyimide film having an elastic modulus of 6.9 GPa as a base film was used. The initial resistance value (R1) of the connection structure was 0.25Ω, and the initial resistance was evaluated as ◎. The resistance value (R2) after the reliability test was 0.6Ω, ΔR was 0.35Ω, and the reliability was evaluated as ◎. Therefore, the overall judgment was ◎.

<Comparative Example 3>
As shown in Table 2, the first electronic component using a cycloolefin copolymer film having an elastic modulus of 2.6 GPa as a base film was used. As the conductive particles, particles having nickel as fine particles and having protrusions on the surface were used. The area ratio of the protrusions to the surface area in the absence of the conductive particle protrusions was 55%. Further, the compression elastic modulus at 30% deformation of the conductive particles was 28 MPa. Using the anisotropic conductive film to which the conductive particles were added, the first electronic component and the second electronic component were connected to obtain a connection structure. The initial resistance value (R1) of the connection structure was 0.52Ω, and the evaluation of the initial resistance was x. The resistance value (R2) after the reliability test was 2.72Ω, ΔR was 2.2Ω, and the evaluation of reliability was x. Therefore, the comprehensive judgment was x.

<Example 1>
As shown in Table 2, the first electronic component using a cycloolefin copolymer film having an elastic modulus of 2.6 GPa as a base film was used. As the conductive particles, particles having nickel as fine particles and having protrusions on the surface were used. The area ratio of the protrusions to the surface area in the absence of the conductive particle protrusions was 55%. Moreover, the compression elastic modulus at the time of 30% deformation of the conductive particles was 32 MPa. Using the anisotropic conductive film to which the conductive particles were added, the first electronic component and the second electronic component were connected to obtain a connection structure. The initial resistance value (R1) of the connection structure was 0.28Ω, and the initial resistance was evaluated as ◎. The resistance value (R2) after the reliability test was 0.69Ω, ΔR was 0.51Ω, and the reliability was evaluated as ◯. Therefore, the overall judgment was “good”.

<Example 2>
As shown in Table 2, a connection structure was obtained in the same manner as in Example 1, except that conductive particles having a compression elastic modulus at 30% deformation of 49 MPa were used. The initial resistance value (R1) of the connection structure was 0.25Ω, and the initial resistance was evaluated as ◎. The resistance value (R2) after the reliability test was 0.59Ω, ΔR was 0.34Ω, and the reliability was evaluated as ◎. Therefore, the overall judgment was ◎.

<Example 3>
As shown in Table 2, a connection structure was obtained in the same manner as in Example 1 except that conductive particles having a compression elastic modulus at 30% deformation of 101 MPa were used. The initial resistance value (R1) of the connection structure was 0.29Ω, and the initial resistance was evaluated as ◎. The resistance value (R2) after the reliability test was 0.62Ω, ΔR was 0.33Ω, and the reliability was evaluated as ◎. Therefore, the overall judgment was ◎.

<Comparative Example 4>
As shown in Table 2, a connection structure was obtained in the same manner as in Example 1 except that conductive particles having a compressive elastic modulus at 30% deformation of 197 MPa were used. The initial resistance value (R1) of the connection structure was 0.91Ω, and the evaluation of the initial resistance was x. The resistance value (R2) after the reliability test was 3.31Ω, ΔR was 2.40Ω, and the evaluation of reliability was x. Therefore, the comprehensive judgment was x.

<Comparative Example 5>
As shown in Table 2, the first electronic component having a base film made of a PET film having an elastic modulus of 5.3 GPa was used. As the conductive particles, particles having nickel as fine particles and having protrusions on the surface were used. The area ratio of the protrusions to the surface area in the absence of the conductive particle protrusions was 55%. Further, the compression elastic modulus at 30% deformation of the conductive particles was 28 MPa. Using the anisotropic conductive film to which the conductive particles were added, the first electronic component and the second electronic component were connected to obtain a connection structure. The initial resistance value (R1) of the connection structure was 0.51Ω, and the evaluation of the initial resistance was x. The resistance value (R2) after the reliability test was 2.63Ω, ΔR was 2.12Ω, and the evaluation of reliability was x. Therefore, the comprehensive judgment was x.

<Example 4>
As shown in Table 2, the first electronic component having a base film made of a PET film having an elastic modulus of 5.3 GPa was used. As the conductive particles, particles having nickel as fine particles and having protrusions on the surface were used. The area ratio of the protrusions to the surface area in the absence of the conductive particle protrusions was 55%. Moreover, the compression elastic modulus at the time of 30% deformation of the conductive particles was 32 MPa. Using the anisotropic conductive film to which the conductive particles were added, the first electronic component and the second electronic component were connected to obtain a connection structure. The initial resistance value (R1) of the connection structure was 0.29Ω, and the initial resistance was evaluated as ◎. The resistance value (R2) after the reliability test was 0.64Ω, ΔR was 0.35Ω, and the reliability was evaluated as ◎. Therefore, the overall judgment was ◎.

<Example 5>
As shown in Table 2, a connection structure was obtained in the same manner as in Example 4 except that conductive particles having a compression elastic modulus at 30% deformation of 49 MPa were used. The initial resistance value (R1) of the connection structure was 0.24Ω, and the initial resistance was evaluated as ◎. The resistance value (R2) after the reliability test was 0.56Ω, ΔR was 0.32Ω, and the reliability was evaluated as ◎. Therefore, the overall judgment was ◎.

<Example 6>
As shown in Table 2, a connection structure was obtained in the same manner as in Example 4 except that conductive particles having a compression elastic modulus at 30% deformation of 101 MPa were used. The initial resistance value (R1) of the connection structure was 0.25Ω, and the initial resistance was evaluated as ◎. The resistance value (R2) after the reliability test was 0.55Ω, ΔR was 0.30Ω, and the reliability was evaluated as ◎. Therefore, the overall judgment was ◎.

<Comparative Example 6>
As shown in Table 2, a connection structure was obtained in the same manner as in Example 4 except that conductive particles having a compressive elastic modulus at 30% deformation of 197 MPa were used. The initial resistance value (R1) of the connection structure was 0.81Ω, and the evaluation of the initial resistance was x. The resistance value (R2) after the reliability test was 2.51Ω, ΔR was 1.70Ω, and the evaluation of reliability was x. Therefore, the comprehensive judgment was x.

<Example 7>
As shown in Table 3, the first electronic component using a PET film having an elastic modulus of 5.3 GPa as a base film was used. As the conductive particles, particles having nickel as fine particles and having protrusions on the surface were used. The area ratio of the protrusions to the surface area in the absence of the conductive particle protrusions was 9%. Moreover, the compression elastic modulus at the time of 30% deformation of the conductive particles was 49 MPa. Using the anisotropic conductive film to which the conductive particles were added, the first electronic component and the second electronic component were connected to obtain a connection structure. The initial resistance value (R1) of the connection structure was 0.33Ω, and the initial resistance was evaluated as ◯. The resistance value (R2) after the reliability test was 0.79Ω, ΔR was 0.46Ω, and the reliability was evaluated as ◎. Therefore, the overall judgment was “good”.

<Example 8>
As shown in Table 3, a connection structure was obtained in the same manner as in Example 7 except that conductive particles having an area ratio of protrusions to the surface area of 29% when no protrusions were used were used. The initial resistance value (R1) of the connection structure was 0.26Ω, and the initial resistance was evaluated as ◎. The resistance value (R2) after the reliability test was 0.62Ω, ΔR was 0.36Ω, and the evaluation of reliability was ◎. Therefore, the overall judgment was ◎.

<Example 9>
As shown in Table 3, a connection structure was obtained in the same manner as in Example 7 except that conductive particles having an area ratio of protrusions to a surface area of 81% when no protrusions were used were used. The initial resistance value (R1) of the connection structure was 0.23Ω, and the initial resistance was evaluated as ◎. The resistance value (R2) after the reliability test was 0.55Ω, ΔR was 0.32Ω, and the reliability was evaluated as ◎. Therefore, the overall judgment was ◎.

<Example 10>
As shown in Table 3, a connection structure was obtained in the same manner as in Example 7, except that conductive particles having an area ratio of protrusions of 91% in the surface area when no protrusions were used were used. The initial resistance value (R1) of the connection structure was 0.28Ω, and the initial resistance was evaluated as ◎. The resistance value (R2) after the reliability test was 0.75Ω, ΔR was 0.47Ω, and the reliability was evaluated as ◎. Therefore, the overall judgment was ◎.

<Example 11>
As shown in Table 3, a connection structure was obtained in the same manner as in Example 7 except that conductive particles in which the area ratio of the protrusions to the surface area in the absence of the protrusions was 98% were used. The initial resistance value (R1) of the connection structure was 0.35Ω, and the initial resistance was evaluated as ◯. The resistance value (R2) after the reliability test was 0.91Ω, ΔR was 0.56Ω, and the reliability was evaluated as ◯. Therefore, the overall judgment was “good”.

<Example 12>
As shown in Table 3, a connection structure was obtained in the same manner as in Example 7 except that conductive particles having an area ratio of protrusions to a surface area of 110% when no protrusions were used were used. The initial resistance value (R1) of the connection structure was 0.38Ω, and the initial resistance was evaluated as ◯. The resistance value (R2) after the reliability test was 0.98Ω, ΔR was 0.60Ω, and the reliability was evaluated as ◯. Therefore, the overall judgment was “good”.

<Example 13>
As shown in Table 3, the first electronic component using a PET film having an elastic modulus of 5.3 GPa as a base film was used. As the conductive particles, particles having palladium as fine particles and having protrusions on the surface were used. The area ratio of the protrusions to the surface area in the absence of the conductive particle protrusions was 55%. Moreover, the compression elastic modulus at the time of 30% deformation of the conductive particles was 52 MPa. Using the anisotropic conductive film to which the conductive particles were added, the first electronic component and the second electronic component were connected to obtain a connection structure. The initial resistance value (R1) of the connection structure was 0.23Ω, and the initial resistance was evaluated as ◎. The resistance value (R2) after the reliability test was 0.53Ω, ΔR was 0.30Ω, and the evaluation of reliability was ◎. Therefore, the overall judgment was ◎.

<Example 14>
As shown in Table 3, the first electronic component using a PET film having an elastic modulus of 5.3 GPa as a base film was used. As the conductive particles, those having aluminum oxide attached as fine particles and having protrusions on the surface were used. The area ratio of the protrusions to the surface area in the absence of the conductive particle protrusions was 55%. Moreover, the compression elastic modulus at the time of 30% deformation of the conductive particles was 51 MPa. Using the anisotropic conductive film to which the conductive particles were added, the first electronic component and the second electronic component were connected to obtain a connection structure. The initial resistance value (R1) of the connection structure was 0.22Ω, and the evaluation of the initial resistance was ◎. The resistance value (R2) after the reliability test was 0.51Ω, ΔR was 0.29Ω, and the evaluation of reliability was ◎. Therefore, the overall judgment was ◎.

  In the case where the conductive particles do not have a protrusion as in Comparative Examples 1 and 2 and the conventional example, when an electronic component having a base film with an elastic modulus of 5 GPa or less is connected, the initial resistance of the connection structure The value was great. When an electronic component having a base film with an elastic modulus exceeding 5.3 GPa was connected as in the conventional example, the initial resistance value of the connection structure was low.

  In addition, when the conductive particles having protrusions were soft as in Comparative Examples 3 and 5, although there were no wiring cracks, the initial resistance value tended to be high. Moreover, when the conductive particles having the protrusions were hard as in Comparative Examples 4 and 6, the occurrence of wiring cracks was confirmed.

  On the other hand, as in Examples 1 to 14, by using conductive particles having a compression elastic modulus at 30% deformation of the conductive particles in the range of 30 to 120 MPa and having protrusions on the surface, It was confirmed that the resistance value and the resistance value after the reliability test were within a favorable range, and that the increase in the resistance value after the reliability test was suppressed.

  In addition, as in Examples 8 to 10, by using conductive particles in which the area ratio of the protrusions occupying the surface area when there is no protrusion is 20% or more and 95% or less, excellent after the initial and reliability tests. It was confirmed that the electrical conductivity was obtained.

DESCRIPTION OF SYMBOLS 10 1st electronic component, 11 terminal, 12 1st support substrate, 20 2nd electronic component, 21 2nd support substrate, 22 terminal, 30 anisotropic conductive film, 31 binder resin, 33 electroconductive particle, 36 core particles, 37 metal layer, 38 first metal layer, 39 second metal layer, 40 fine particles, P protrusion

Claims (11)

A binder resin,
Containing conductive particles contained in the binder resin and having a compression elastic modulus at 30% deformation of 30 MPa or more and 120 MPa or less;
An anisotropic conductive material in which the conductive particles have protrusions on the surface.   2. The anisotropic conductive material according to claim 1, wherein the area ratio of the protrusions to the surface area in the absence of the conductive particle protrusions is 20% to 95%.   3. The anisotropic conductive material according to claim 1, wherein the protrusions of the conductive particles are composed of one or more selected from the group consisting of nickel, palladium, and titanium.   The conductive particles cover the core particles, the first metal layer covering the core particles, the fine particles attached to the first metal layer, and the first metal layer and the fine particles. The anisotropic conductive material according to claim 1, comprising two metal layers.   The anisotropic conductive material according to claim 4, wherein the fine particles are composed of one or more selected from the group consisting of nickel, palladium, titanium, and metal oxide. The first metal layer comprises nickel;
The anisotropic conductive material according to claim 4, wherein the second metal layer contains gold.   The anisotropic conductive material according to claim 1, wherein the binder resin is a radical curable type. A first electronic component having terminals formed on the first support substrate;
A second electronic component having terminals formed on the second support substrate;
An anisotropic conductive film comprising a cured product of an anisotropic conductive material containing conductive particles that connect the terminal of the first electronic component and the terminal of the second electronic component;
The anisotropic conductive material contains a binder resin and conductive particles that are contained in the binder resin and have a compression elastic modulus at 30% deformation of 30 MPa or more and 120 MPa or less. The connection structure which has a projection part in.   The connection structure according to claim 8, wherein an elastic modulus of at least one of the first support substrate and the second support substrate is 5.5 GPa or less.   A touch panel device comprising the connection structure according to claim 8. A first electronic component having a terminal formed on the first support substrate and a second electronic component having a terminal formed on the second support substrate are included in the binder resin and the binder resin. , Containing conductive particles having a compressive elastic modulus at 30% deformation of 30 MPa or more and 120 MPa or less, and the conductive particles are bonded by interposing an anisotropic conductive adhesive film having a protrusion on the surface, A method for producing a connection structure, wherein an anisotropic adhesive film is cured to obtain a connection structure.

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