JP7234032B2 - Method for manufacturing adhesive film, method for manufacturing adhesive film, and connected body - Google Patents

Description

The present technology relates to a method for manufacturing an adhesive film that connects electronic components, a method for manufacturing an adhesive film, and a connecting body.

2. Description of the Related Art Conventionally, liquid crystal display devices have been widely used as various display means. In recent years, from the standpoint of finer pitch, lighter weight, and thinner liquid crystal display devices, so-called COG (chip on glass), in which a liquid crystal driving IC is directly mounted on the substrate of the liquid crystal display panel, and a liquid crystal driving circuit. A so-called FOG (film on glass) is employed in which a flexible substrate having a .DELTA.

For example, a connection method using a thermosetting anisotropic conductive film generally requires a high heat press temperature, which tends to increase the thermal impact on electronic components such as an IC for driving a liquid crystal and the substrate. When the thermal shock to the substrate increases, the substrate (particularly the terminal portion of the substrate) may warp. Also, when the temperature drops to room temperature after the anisotropic conductive film is connected, the binder may shrink due to the temperature difference, and the substrate may warp. As a result of warping of the substrate, there is a possibility that connection failure of the liquid crystal driving IC may occur.

For this reason, mounting at a low temperature using, for example, a photocurable adhesive (film) is desired. Moreover, in recent years, there are cases where substrates (display panels) are made of materials having lower heat resistance than glass (for example, plastic substrates), so the above demands are increasing.

JP 2012-253282 A

Photo-curable adhesives (films) require precise conditions to the extent that they need to be connected in a multi-layer structure of two or more layers. For example, if the shrinkage of the binder is large, the substrate may warp and the adhesive strength may decrease.

The present technology has been proposed in view of such conventional circumstances, and an object of the present technology is to provide a method for manufacturing an adhesive film that provides high adhesive strength, an adhesive film, and a method for manufacturing a connected body.

A method for producing an adhesive film according to the present technology forms a first resin layer in which first rubber particles are dispersed in a binder containing a film-forming resin, a radically polymerizable compound, and a photopolymerization initiator. forming a second resin layer in which second rubber particles are dispersed in the binder; and bonding the first resin layer and the second resin layer together, When the first rubber particles and the film-forming resin were blended at a weight ratio of 1:1, measurement was performed using a viscoelasticity measuring device under conditions of a frequency of 10 Hz and a temperature increase rate of 3°C/min in a tensile mode. When the storage elastic modulus at 20° C. is 1000 MPa or more and 1200 MPa or less, and the second rubber particles and the film-forming resin are blended at a weight ratio of 1:1, the frequency is measured in a tensile mode using a viscoelasticity measuring device. The storage elastic modulus at 20° C. measured under the conditions of 10 Hz and a heating rate of 3° C./min is 750 MPa or more and 950 MPa or less.

An adhesive film according to the present technology includes a first resin layer in which first rubber particles are dispersed in a binder containing a film-forming resin, a radically polymerizable compound, and a photopolymerization initiator; a second resin layer in which second rubber particles are dispersed, and when the first rubber particles and the film-forming resin are blended at a weight ratio of 1:1, a viscoelasticity measuring device is used to The storage elastic modulus at 20° C. measured under the conditions of a frequency of 10 Hz and a heating rate of 3° C./min in a tensile mode is 1000 MPa or more and 1200 MPa or less, and the weight ratio of the second rubber particles and the film-forming resin is 1:1. ratio, the storage elastic modulus at 20° C. measured using a viscoelasticity measuring device under the conditions of a frequency of 10 Hz and a heating rate of 3° C./min is 750 MPa or more and 950 MPa or less.

A method for manufacturing a connection body according to the present technology connects a first terminal of a first electronic component and a second terminal of a second electronic component using the adhesive film described above.

According to the present technology, it is possible to reduce the shrinkage of the binder by relieving the stress and obtain high adhesive strength.

FIG. 1 is a cross-sectional view showing an example of an anisotropic conductive film. FIG. 2 is a cross-sectional view showing an example of a state in which an anisotropic conductive film is arranged on terminals of a substrate. FIG. 3 is a cross-sectional view showing an example of a state in which electronic components are arranged on an anisotropic conductive film. FIG. 4 is a cross-sectional view showing an example of a state in which the anisotropic conductive film is cured.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail in the following order with reference to the drawings.
1. Adhesive film2. Method for producing adhesive film3. 4. Manufacturing method of connecting body. Example

<1. Adhesive film>
The adhesive film according to the present embodiment includes a first resin layer in which first rubber particles are dispersed in a binder containing a film-forming resin, a radically polymerizable compound, and a photopolymerization initiator; and a second resin layer in which second rubber particles are dispersed. Here, by forming the first resin layer and the second resin layer with the same binder, it can be handled as a single layer film.

In addition, when the first rubber particles and the film-forming resin were blended at a weight ratio of 1:1, measurement was performed using a viscoelasticity measuring device under the conditions of a frequency of 10 Hz and a temperature increase rate of 3°C/min in a tensile mode. The lower limit of the storage modulus at 20°C is 1000 MPa or more, preferably 1050 MPa or more, and the upper limit of the storage modulus at 20°C is 1200 MPa or less, preferably 1150 MPa or less. In addition, when the second rubber particles and the film-forming resin were blended at a weight ratio of 1:1, measurement was performed using a viscoelasticity measuring device under the conditions of a frequency of 10 Hz and a temperature increase rate of 3°C/min in a tensile mode. The lower limit of the storage modulus at 20°C is 750 MPa or more, preferably 800 MPa or more, and the upper limit of the storage modulus at 20°C is 950 MPa or less, preferably 900 MPa. As a result, the stress can be relaxed, the shrinkage of the binder can be suppressed, and high adhesive strength can be obtained. In this specification, the storage elastic modulus measured under the above conditions is abbreviated as "the storage elastic modulus of the first rubber particles at 20°C", "the storage elastic modulus of the second rubber particles at 20°C", and the like. sometimes.

The content of the first rubber particles in the first resin layer is 10 parts by mass or more and 30 parts by mass or less with respect to 90 parts by mass of the binder, and the content of the second rubber particles in the second resin layer is It is preferably 10 parts by mass or more and 30 parts by mass or less with respect to 90 parts by mass of the binder.

The content of the film-forming resin in the first resin layer is 30 parts by mass or more and 60 parts by mass or less with respect to 90 parts by mass of the binder, and the content of the film-forming resin in the second resin layer is 90 parts by mass of the binder. is preferably 30 parts by mass or more and 60 parts by mass or less.

The adhesive film may have a two-layer structure or a three-layer or more structure. The total average thickness of all layers of the adhesive film can be appropriately selected depending on the purpose, and can be, for example, 5 to 30 μm. The lower limit of the average thickness per layer of the adhesive film is preferably 3 μm or more, more preferably 5 μm or more. Also, the upper limit of the average thickness of one layer of the adhesive film is preferably 25 μm or less, more preferably 20 μm or less, because if the thickness is too large, the effect of suppressing shrinkage becomes difficult to appear. The thickness of each layer may be the same or different, and can be adjusted as appropriate. When the adhesive film is used for connection between terminals (electrodes) of electronic components that are affected by pressure, the thickness of each layer preferably satisfies the requirement for the average thickness per layer, and the total thickness is 5 to 30 μm. It is more preferable to be

The lower limit of the average particle size of the first rubber particles and the second rubber particles is preferably 10 nm or more, more preferably 30 nm or more, and still more preferably 50 nm or more, and the upper limit of the average particle size is preferably 3000 nm or less. It is more preferably 1000 nm or less, still more preferably 500 nm or less. It is possible to relax the stress when the adhesive film is pressed or after it is cured.

The average particle diameter of rubber particles can be a value measured by the following method. First, arbitrarily selected primary particles of rubber particles are observed with a scanning electron microscope (SEM, manufactured by Hitachi, Ltd., product name: S-800) (magnification: 5000 times), and the maximum and minimum diameters are observed. to measure. The square root of the product of this maximum diameter and minimum diameter is taken as the primary particle diameter of the particle. Then, the primary particle diameters of 50 arbitrarily selected rubber particles are measured as described above, and the average value is defined as the average particle diameter.

An anisotropic conductive film in which conductive particles are dispersed in a binder will be described below as an example of the adhesive film of the present embodiment. A photocurable anisotropic conductive film is preferably used as the anisotropic conductive film, and it may be a photoradical type or a photocationic type. Further, a photo-radical system and a photo-cation system may be used in combination.

FIG. 1 is a cross-sectional view showing an example of an anisotropic conductive film. As shown in FIG. 1, an anisotropic conductive film 10 comprises a conductive particle-containing layer 11 containing conductive particles 13 and first rubber particles, and an insulating resin layer 12 containing second rubber particles. have. The storage modulus of the first rubber particles at 20°C is greater than the storage modulus of the second rubber particles at 20°C, and the lower limit of the difference is preferably 100 MPa or more, more preferably 200 MPa or more. is preferably 400 MPa or less, more preferably 300 MPa or less. With such a configuration, when the insulating resin layer side is pressed by a heating tool, the amount of deformation of the conductive particle-containing layer is reduced, so that poor connection between the substrate and the electronic component can be more effectively suppressed. .

Hereinafter, as an example of the present embodiment, a photoradical anisotropic conductive film will be described in the order of the conductive particle-containing layer and the insulating resin layer.

[Conductive particle-containing layer]
The conductive particle-containing layer comprises, for example, a film-forming resin (polymer), a radically polymerizable compound as a reactive resin, and a binder containing a photoradical polymerization initiator, in which conductive particles and first rubber particles are dispersed. configured.

Film-forming resins are used to improve film-forming properties, and examples thereof include bisphenol S-type phenoxy resins, phenoxy resins having a fluorene skeleton, polystyrene, polyacrylonitrile, polyphenylene sulfide, polytetrafluoroethylene, polycarbonate, and the like. These can be used alone or in combination of two or more. Among these resins, bisphenol S-type phenoxy resin is preferably used from the viewpoint of film forming state, connection reliability, and the like. A phenoxy resin is a polyhydroxy polyether synthesized from bisphenols and epichlorohydrin. Specific examples of commercially available phenoxy resins include Nippon Steel & Sumikin Chemical Co., Ltd.'s trade name "FA290".

The lower limit of the content of the film-forming resin is preferably 30 parts by mass or more, more preferably 35 parts by mass or more relative to 90 parts by mass of the binder, and the upper limit of the content of the film-forming resin is relative to 90 parts by mass of the binder. is preferably 60 parts by mass or less, more preferably 55 parts by mass or less. The film-forming resin may be used singly or in combination of two or more. When two or more film-forming resins are used in combination, the total amount preferably satisfies the above content range.

A radically polymerizable compound is a substance having a functional group that is polymerized by an active radical, and examples thereof include (meth)acrylates and maleimide compounds. Moreover, the photoradical polymerizable compound can be used in either a monomer or oligomer state, and a monomer and an oligomer may be used in combination. In this specification, (meth)acrylate is meant to include both acrylic acid ester (acrylate) and methacrylic acid ester (methacrylate).

(Meth)acrylates include photopolymerizable oligomers such as epoxy acrylate oligomers, urethane acrylate oligomers, polyether acrylate oligomers, and polyester acrylate oligomers; trimethylolpropane triacrylate, polyethylene glycol diacrylate, polyalkylene glycol diacrylate, and pentaerythritol acrylate. , 2-cyanoethyl acrylate, cyclohexyl acrylate, dicyclopentenyl acrylate, dicyclobentenyloxyethyl acrylate, 2-(2-ethoxyethoxy)ethyl acrylate, 2-ethoxyethyl acrylate, 2-ethylhexyl acrylate, n-hexyl acrylate, 2 - hydroxyethyl acrylate, hydroxypropyl acrylate, isobornyl acrylate, isodecyl acrylate, isooctyl acrylate, n-lauryl acrylate, 2-methoxyethyl acrylate, 2-phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, neopentyl glycol diacrylate , photopolymerizable monofunctional or multifunctional acrylate monomers such as dipentaerythritol hexaacrylate.

The lower limit of the content of the radically polymerizable compound is preferably 10 parts by mass or more, more preferably 20 parts by mass or more relative to 90 parts by mass of the binder, and the upper limit of the content of the radically polymerizable compound is 90 parts by mass of the binder. is preferably 60 parts by mass or less, more preferably 50 parts by mass or less. The radically polymerizable compound may be used singly or in combination of two or more. When two or more radically polymerizable compounds are used in combination, the total amount preferably satisfies the above content range.

The radical photopolymerization initiator can be appropriately selected from known radical photopolymerization initiators and used. Examples of photoradical polymerization initiators include alkylphenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, oxime ester-based photopolymerization initiators, and the like, and oxime ester-based photopolymerization initiators are particularly preferred. .

Specific examples of photoradical polymerization initiators include bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (IRGACURE819), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)- Butanone-1 (IRGACURE369), 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (IRGACURE379), 1.2- Octanedione, 1-[4-(phenylthio)-,2-(O-benzoyloxime)] (IRGACURE OXE01), 2-hydroxy-2-cyclohexylacetophenone (IRGACURE 184), α-hydroxy-α,α'-dimethylacetophenone (DAROCUR1173), 2,2-dimethoxy-2-phenylacetophenone (IRGACURE651), 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone (DAROCUR2959), 2-hydroxy-1-{4- [2-hydroxy-2-methyl-propionyl]-benzyl}phenyl}-2-methyl-propan-1-one (IRGACURE 127, manufactured by BASF) and the like.

The content of the radical photopolymerization initiator in the conductive particle-containing layer can be, for example, 0.1 to 10 wt %. A photoradical polymerization initiator may be used individually by 1 type, and may use 2 or more types together. When two or more photoradical polymerization initiators are used in combination, the total amount preferably satisfies the above content range.

As the conductive particles, known conductive particles used in anisotropic conductive films can be used. For example, on the surface of various metals such as nickel, iron, copper, aluminum, tin, lead, chromium, cobalt, silver, and gold, particles of metal alloys, metal oxides, carbon, graphite, glass, ceramics, plastics, etc. Examples thereof include metal-coated particles, particles coated with an insulating thin film on the surface of these particles, and the like, and two or more of these particles may be used in combination. When the resin particles are coated with a metal on their surfaces, the resin particles may be, for example, epoxy resins, phenol resins, acrylic resins, acrylonitrile-styrene (AS) resins, benzoguanamine resins, divinylbenzene-based resins, styrene-based resins, or the like. of particles can be used. The surface of the conductive particles may be subjected to insulation treatment by a known technique.

The average particle size of the conductive particles is usually 1-30 μm, preferably 2-20 μm, more preferably 2.5-15 μm. Also, the average particle density of the conductive particles in the binder resin is preferably 100 to 100,000/mm ² , more preferably 500 to 80,000/mm ² from the viewpoint of connection reliability and insulation reliability. This number density can be obtained by observing the film from a plan view using an optical microscope. As an example, the number of particles may be N=200 or more. Further, the observation area can be set so that the area of 200 μm ^{2 or} more with one side of 50 μm or more and a total area of 2 mm ^{2 or} more.

Also, the conductive particles may be dispersed in an insulating resin, may be independent of each other in a plan view of the film, or may be arbitrarily arranged. When conductive particles are arranged, the number density, the distance between the conductive particles, and the like can be set according to the size and layout of the electrodes to be anisotropically connected. For this reason, it is effective in improving trapping and suppressing short circuits, and is expected to have cost reduction effects such as an improvement in yield.

The content of the conductive particles in the conductive particle-containing layer is preferably, for example, 2 to 50 wt%, more preferably 3 to 30 wt%, from the viewpoint of improving the conduction resistance of the connector. The conductive particles may be used singly or in combination of two or more. When two or more types of conductive particles are used in combination, the total amount preferably satisfies the above content range. Moreover, it is preferable that the total amount of the average particle density of the conductive particles in the conductive particle-containing layer also satisfies the above range of content.

The first rubber particles are used for the purpose of absorbing the stress generated in the binder resin after mounting by elastic deformation and suppressing the warp of the substrate. Examples of the first rubber particles include butadiene rubber, acrylic rubber, nitrile rubber, and silicone rubber. In particular, as the first rubber particles, rubber-based particles are used as a core material (core layer) from the viewpoint of suppressing warping of the substrate, and a resin (eg, acrylic resin, epoxy resin, etc.) is grafted onto the surface of the core material. Particles having a core-shell structure in which a surface layer (shell layer) is formed by polymerization are preferably used.

The average particle size of the first rubber particles is preferably smaller than the average particle size of the conductive particles from the viewpoint of ensuring sufficient connectivity between the substrate and the electronic component. The upper limit of the average particle size of the first rubber particles is 500 nm or less, more preferably 300 nm or less, and even more preferably 200 nm or less, from the viewpoint of suppressing warping of the substrate. Also, the lower limit of the average particle size of the first rubber particles can be set to, for example, 50 nm or more.

The lower limit of the storage elastic modulus of the first rubber particles at 20°C is 1000 MPa or higher, preferably 1050 MPa or higher, and the upper limit of the storage elastic modulus at 20°C is 1200 MPa or lower, preferably 1150 MPa or lower.

The lower limit of the content of the first rubber particles is preferably 10 parts by mass or more, more preferably 15 parts by mass or more with respect to 90 parts by mass of the binder, and the lower limit of the content of the first rubber particles is 90 parts by mass of the binder. It is preferably 30 parts by mass or less, more preferably 25 parts by mass or less. A 1st rubber particle may be used individually by 1 type, and may use 2 or more types together. When two or more kinds of first rubber particles are used in combination, the total amount preferably satisfies the above content range.

The conductive particle-containing layer may contain components other than the components described above. As another component, for example, a silane coupling agent can be used. Examples of silane coupling agents that can be used include epoxy-based silane coupling agents, acrylic-based silane coupling agents, thiol-based silane coupling agents, and amine-based silane coupling agents.

[Insulating resin layer]
The insulating resin layer is formed by dispersing the second rubber particles in a binder containing, for example, a film-forming resin (polymer), a radically polymerizable compound as a reactive resin, and a photoradical polymerization initiator. be done. The lower limit of the content of the second rubber particles is preferably 10 parts by mass or more, more preferably 15 parts by mass or more with respect to 90 parts by mass of the binder, and the lower limit of the content of the second rubber particles is 90 parts by mass of the binder. It is preferably 30 parts by mass or less, more preferably 25 parts by mass or less.

The storage elastic modulus of the second rubber particles at 20°C is smaller than the storage elastic modulus of the first rubber particles in the conductive particle-containing layer at 20°C. The lower limit of the storage modulus of the second rubber particles at 20°C is 750 MPa or more, preferably 800 MPa or more, and the upper limit of the storage modulus of the second rubber particles at 20°C is 950 MPa or less, preferably 900 MPa. Preferred conditions for other components constituting the insulating resin layer are the same as those for the conductive particle-containing layer described above.

According to the anisotropic conductive film described above, since the internal stress can be reduced, the warp of the substrate is suppressed, the connection failure between the substrate and the electronic component is suppressed, and the bonding strength between the substrate and the electronic component is reduced. can be improved. Although an adhesive film containing conductive particles such as an anisotropic conductive film has been described as an example, the conductive particles do not necessarily need to be contained in the present technology.

<2. Method for producing an adhesive film>
The method for manufacturing a connected body according to the present embodiment forms a first resin layer in which first rubber particles are dispersed in a binder containing a film-forming resin, a polymerizable compound, and a photopolymerization initiator. forming a second resin layer in which the second rubber particles are dispersed in a binder; and bonding the first resin layer and the second resin layer together.

The first resin layer and the second resin layer can be the conductive particle-containing layer and the insulating resin layer described above, respectively. By forming the first resin layer and the second resin layer with the same binder, it can be treated as a single layer film. Further, by setting the storage elastic modulus of the first rubber particles and the second rubber particles at 20° C. to the range described above, the stress can be alleviated, the shrinkage of the binder can be suppressed, and high adhesive strength can be obtained.

<3. Method for manufacturing connection body>
In the method for manufacturing a connection body according to the present embodiment, the adhesive film described above is used to connect the first terminal of the first electronic component and the second terminal of the second electronic component. More specifically, a step of placing an anisotropic conductive film on a terminal of a substrate, placing an electronic component on the anisotropic conductive film, pressing the electronic component with a tool, irradiating light, and anisotropic and curing the electrically conductive film. It should be noted that the manufacturing method of the connecting body is applicable not only to electronic components but also to connection between two components.

Hereinafter, as an example, a method for manufacturing a connected body using the photocurable anisotropic conductive film 10 having the conductive particle-containing layer 11 and the insulating resin layer 12 described above will be described.

First, as shown in FIG. 2 , the conductive particle-containing layer 11 side of the anisotropic conductive film 10 is placed on the terminal row 20 a of the first electronic component 20 . Examples of the first electronic component 20 include LCD (Liquid Crystal Display) panels, flat panel display (FPD) applications such as organic EL (OLED), transparent substrates such as touch panel applications, and printed wiring boards (PWB). be done. The material of the printed wiring board is not particularly limited. For example, glass epoxy such as FR-4 base material may be used, plastic such as thermoplastic resin, and ceramic may also be used. The transparent substrate is not particularly limited as long as it has high transparency, and examples thereof include glass substrates and plastic substrates.

Next, as shown in FIGS. 3 and 4, a second electronic component 22 is placed on the insulating resin layer 12 of the anisotropic conductive film 10, and the second electronic component 22 is pressed with a thermocompression bonding tool. The anisotropic conductive film is cured by irradiating it with light. As a result, the resin forming the anisotropic conductive film 10 is melted by the heat of the thermocompression bonding tool, the second electronic component 22 is sufficiently pushed by the thermocompression bonding tool, and the conductive particles 13 are sandwiched between the terminals. Since the resin is cured at , excellent conductivity can be obtained.

The heating by the thermocompression bonding tool is preferably performed at a temperature of 160° C. or lower, more preferably 140° C. or lower, and still more preferably 120° C. or lower. By applying pressure at such a low temperature, the influence of heat on the first electronic component 20 and the second electronic component 22 can be suppressed. Further, the pressing pressure by the thermocompression bonding tool is preferably 0.1 MPa to 100 MPa, for example. The heating and pressing time can be, for example, 0.5 to 120 seconds.

A cushioning material may also be used between the crimping tool and the second electronic component 22 . As the cushioning material, polytetrafluoroethylene (PTFE), polyimide, glass cloth, silicon rubber, or the like can be used.

Light irradiation may be performed from the first electronic component 20 side or may be performed from the second electronic component 22 side. Moreover, light irradiation may be performed from the lateral side of the thermocompression bonding tool. Further, the light irradiation may have a constant illuminance, or may be stepwise or continuously increased or decreased in illuminance. The light to be irradiated can be selected from wavelength bands such as ultraviolet (UV), visible light, infrared (IR), etc., according to the curing system of the anisotropic conductive film. Among these, it is preferable that the light emitted from the light irradiator contains ultraviolet rays having high energy.

Ultraviolet rays have a wavelength of 10 nm to 400 nm. Ultraviolet rays with short wavelengths have high energy, but on the other hand, it is difficult for them to reach the inside of the resin. It has permeable properties. In addition, when the wavelength is 200 nm or less, it is likely to be consumed to decompose oxygen or to be absorbed by oxygen. Therefore, the light emitted from the light irradiator preferably contains near-ultraviolet rays having a wavelength of 200 nm or more. Examples of the light source that emits light containing near-ultraviolet rays include high-pressure mercury lamps that output high wavelengths of 248 nm, 313 nm, 334 nm, 365 nm, 405 nm, and 436 nm.

The second electronic component 22 has a terminal row 22a that faces the terminal row 20a of the first electronic component 20 . The second electronic component 22 is not particularly limited and can be appropriately selected according to the purpose. Examples of the second electronic component 22 include an IC (Integrated Circuit), a flexible printed circuit (FPC), a tape carrier package (TCP) substrate, and a COF (Chip On Film) in which an IC is mounted on an FPC. be done.

According to the manufacturing method of the connected body as described above, by using the anisotropic conductive film in which the storage elastic modulus at 20° C. of the first rubber particles and the second rubber particles is within the above range, Since the amount of deformation of the conductive particle-containing layer can be reduced and the internal stress can be reduced, it is possible to suppress warping of the substrate and obtain a connection body with good conduction resistance and bonding strength.

In the above embodiment, the second electronic component 22 is pressed by a thermocompression bonding tool and irradiated with light to cure the anisotropic conductive film. Continuity is not particularly limited. For example, the anisotropic conductive film may be cured in advance before pressing the electronic component with the heating tool. That is, the anisotropic conductive film may be cured by irradiating light first, and then the second electronic component 22 may be pressed by a thermocompression bonding tool. Moreover, the light irradiation may be performed simultaneously with the pressing by the thermocompression bonding tool, or the light irradiation may be performed separately for the temporary compression bonding and the final compression bonding.

<4. Example>
Examples of the present technology will be described below. In this example, a first resin layer containing conductive particles and a second resin layer were laminated to prepare an anisotropic conductive film. Note that the present technology is not limited to these examples.

The following compounds were used in this example.
Phenoxy resin: FA290 (Nippon Steel & Sumikin Chemical Co., Ltd.)
Bifunctional epoxy compound: 840-S (DIC Corporation)
Photocationic polymerization initiator: IRGACURE 290 (BASF Japan Ltd.)
Conductive particles: average particle size 3.2 μm
Particle A: core-shell structure crosslinked rubber particles (average particle diameter 100 nm, storage elastic modulus 1102 MPa at 20°C)
Particle B: Acrylic rubber particles (average particle diameter 70 nm, storage elastic modulus 1373 MPa at 20°C)
Particle C: Acrylic rubber particles (average particle diameter 300 nm, storage elastic modulus 860 MPa at 20°C)
Particle D: Acrylic rubber particles (average particle diameter 600 nm, storage elastic modulus 646 MPa at 20°C)
Particle E: methacrylsilane-treated silica particles (average particle diameter 10 nm, storage modulus 3384 MPa at 20°C)

The storage modulus of the particles at 20°C was measured by the following method. First, a phenoxy resin (FA290 (Nippon Steel & Sumikin Chemical Co., Ltd.) and particles were dispersed so that the weight ratio was 1:1, and the film was formed with a bar coater. (manufactured by A&D Co., Ltd.) in tensile mode (frequency 10 Hz, temperature rise 3 ° C./min), the storage elastic modulus at 20 ° C. is "20% of rubber particles. storage modulus at °C”.

<Example 1-3, Comparative Example 1-6>
[Preparation of anisotropic conductive film]
60 parts by mass of a phenoxy resin, 30 parts by mass of a difunctional epoxy compound, 2 parts by mass of a photocationic polymerization initiator, conductive particles in an amount to give a surface density of 60,000 particles/mm ² , and rubber particles shown in the table below were mixed. The mixture after mixing was coated on PET that had been subjected to release treatment so that the average thickness after drying was 6 μm, and dried at 70° C. for 5 minutes to obtain a conductive particle-containing layer, which was the first resin layer.

20 parts by mass of a phenoxy resin, 30 parts by mass of a bifunctional epoxy compound, 2 parts by mass of a photocationic polymerization initiator, and rubber particles shown in the table below were uniformly mixed. The mixture after mixing was coated on the release-treated PET so that the average thickness after drying was 14 μm, and dried at 70° C. for 5 minutes to obtain an insulating resin layer as a second resin layer.

Using a roll laminator, the conductive particle-containing layer and the insulating resin layer were laminated to obtain an anisotropic conductive film having a two-layer structure.

[Preparation of connecting body]
As an evaluation element, an IC for evaluation under the following conditions was used.
Outline: 1.8mm x 20mm
Bump height; 15 μm

ITO-coated glass with a thickness of 0.5 mm was used as an evaluation substrate to which the evaluation IC was connected.

The anisotropic conductive film was placed on the evaluation substrate so that the conductive particle-containing layer side of the anisotropic conductive film was in contact with the evaluation substrate. After placing the IC for evaluation on the insulating resin layer of the anisotropic conductive film, the anisotropic conductive film was cured by heat pressurization and ultraviolet irradiation to obtain a connected body.

The heat press was performed from the side of the evaluation IC using a heat press head under the conditions of 100° C., 80 MPa, and 5 seconds. The temperature of the heating and pressing head was set so as to reach 100° C. 5 seconds after the start of heating and pressing. Thermal compression was performed by interposing a Teflon (registered trademark) sheet having a thickness of 50 μm as a cushioning material between the thermocompression head and the IC for evaluation.

The ultraviolet irradiation was carried out from the side of the substrate for evaluation using an ultraviolet irradiator (ZUV-C30H: manufactured by Omron Co., Ltd.). The ultraviolet irradiation was started 1 second after the start of heat pressurization and continued for 4 seconds (accumulated amount of light 800 mJ/cm ² ).

[Continuity resistance value of connection body]
The initial connection resistance value (Ω) and the connection resistance value (Ω) after the reliability test were measured for the connection body sample. The connection resistance value was measured by connecting a digital multimeter to the wiring of the evaluation substrate connected to the bumps of the evaluation IC, and measuring the resistance value when a current of 2 mA was applied by the four-terminal method. The initial connection resistance value of 2Ω or less and the connection resistance value of 10Ω or less after the reliability test were evaluated as OK, and the others were evaluated as NG. The reliability test conditions were a temperature of 85° C., a relative humidity of 85%, and 500 hours.

[Die shear strength of connecting body]
For each connecting body sample, the die shear strength of the evaluation IC was measured using a bond tester (series 4000, manufactured by Nordson Advantest Technologies, Inc.) at a tool speed of 0.2 mm/sec.

[judgement]
The initial connection resistance value of the connection body was 2 Ω or less, the connection resistance value after the reliability test was 10 Ω or less, and the connection body had a die shear strength of 30 MPa or more. bottom.

From the results shown in Table 1, the first rubber particles having a storage elastic modulus of 1000 MPa or more and 1200 MPa or less at 20°C when the particles and the film-forming resin are blended at a weight ratio of 1:1, the particles and the film-forming resin and second rubber particles having a storage elastic modulus of 750 MPa or more and 950 MPa or less at 20° C. when blended at a weight ratio of 1:1, suppressing poor connection between the substrate and the electronic component, It was found that the adhesive strength between the substrate and the electronic component was improved. It is considered that this is because the amount of deformation of the conductive particle-containing layer during pressing was reduced and the internal stress was reduced.

10 anisotropic conductive film, 11 conductive particle-containing layer, 12 insulating resin layer, 13 conductive particles, 20 first electronic component, 20a terminal row, 22 second electronic component, 22a terminal row, 23 ultraviolet irradiation device, 24 anisotropic conductive film

Claims (14)

forming a first resin layer in which first rubber particles are dispersed in a binder containing a film-forming resin, a polymerizable compound, and a photopolymerization initiator;
forming a second resin layer in which second rubber particles are dispersed in the binder;
A step of bonding the first resin layer and the second resin layer together,
When the first rubber particles and the film-forming resin were blended at a weight ratio of 1:1, measurement was performed using a viscoelasticity measuring device under conditions of a frequency of 10 Hz and a temperature increase rate of 3°C/min in a tensile mode. Storage modulus at 20 ° C. is 1000 MPa or more and 1200 MPa or less,
In the case where the second rubber particles and the film-forming resin were blended at a weight ratio of 1:1, measurement was performed using a viscoelasticity measuring device under conditions of a frequency of 10 Hz and a temperature increase rate of 3°C/min in a tensile mode. A method for producing an adhesive film having a storage modulus of 750 MPa or more and 950 MPa or less at 20°C. The content of the first rubber particles in the first resin layer is 10 parts by mass or more and 30 parts by mass or less with respect to 90 parts by mass of the binder,
2. The method for producing an adhesive film according to claim 1, wherein the content of said second rubber particles in said second resin layer is 10 parts by mass or more and 30 parts by mass or less with respect to 90 parts by mass of said binder. 3. The method for producing an adhesive film according to claim 1, wherein the average particle size of said first rubber particles and said second rubber particles is 500 nm or less. The content of the film-forming resin in the first resin layer is 30 parts by mass or more and 60 parts by mass or less with respect to 90 parts by mass of the binder,
4. The adhesive film according to any one of claims 1 to 3, wherein the content of the film-forming resin in the second resin layer is 30 parts by mass or more and 60 parts by mass or less with respect to 90 parts by mass of the binder. Production method. 5. The method for producing an adhesive film according to claim 1, wherein said first resin layer further comprises conductive particles dispersed in said binder. a first resin layer in which first rubber particles are dispersed in a binder containing a film-forming resin, a polymerizable compound, and a photopolymerization initiator;
a second resin layer in which second rubber particles are dispersed in the binder;
When the first rubber particles and the film-forming resin were blended at a weight ratio of 1:1, measurement was performed using a viscoelasticity measuring device under conditions of a frequency of 10 Hz and a temperature increase rate of 3°C/min in a tensile mode. Storage modulus at 20 ° C. is 1000 MPa or more and 1200 MPa or less,
In the case where the second rubber particles and the film-forming resin were blended at a weight ratio of 1:1, measurement was performed using a viscoelasticity measuring device under conditions of a frequency of 10 Hz and a temperature increase rate of 3°C/min in a tensile mode. An adhesive film having a storage modulus of 750 MPa or more and 950 MPa or less at 20°C. The content of the first rubber particles in the first resin layer is 10 parts by mass or more and 30 parts by mass or less with respect to 90 parts by mass of the binder,
7. The adhesive film according to claim 6, wherein the content of said second rubber particles in said second resin layer is 10 parts by mass or more and 30 parts by mass or less with respect to 90 parts by mass of said binder. 8. The adhesive film according to claim 6, wherein the average particle size of said first rubber particles and said second rubber particles is 1 [mu]m or less. The content of the film-forming resin in the first resin layer is 30 parts by mass or more and 60 parts by mass or less with respect to 90 parts by mass of the binder,
9. The adhesive film according to any one of claims 6 to 8, wherein the content of the film-forming resin in the second resin layer is 30 parts by mass or more and 60 parts by mass or less with respect to 90 parts by mass of the binder. 10. The adhesive film according to any one of claims 6 to 9, wherein said first resin layer further contains conductive particles in said binder. 10. A method for manufacturing a connecting body for connecting a first component and a second component using the adhesive film according to any one of claims 6 to 9. 11. A method of manufacturing a connector for anisotropically connecting a first terminal of a first electronic component and a second terminal of a second electronic component using the adhesive film according to claim 10. A connection body in which a first component and a second component are connected via the adhesive film according to any one of claims 6 to 9. 11. A connection body in which a first terminal of a first electronic component and a second terminal of a second electronic component are anisotropically connected via the adhesive film according to claim 10.

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