Film-shaped adhesive, adhesive film, connected structure, and method for producing connected structure

Abstract

Provided is a method for producing a connected structure, the method including: a step in which an adhesive film is laminated on a first electrode-formed surface of a first circuit member having a first electrode formed thereon; and a step in which a second circuit member having a second electrode, is placed over the first circuit member to which the adhesive film has been laminated, so that the first electrode and the second electrode face each other, and the resultant stack is bonded together by hot pressing to electrically connect the first electrode and the second electrode to each other. The adhesive film includes a film-shaped adhesive comprising a thermoplastic resin and a radical-polymerizable compound. When the film-shaped adhesive is heated at 170°C for 5 seconds and then examined by a dynamic viscoelasticity measurement, the waveform of a loss tangent (tanδ) has a plurality of maximal values.

Description

Film-like adhesive, adhesive film, connection structure, and method for manufacturing the connection structure

[0001] The present disclosure relates to a film-like adhesive, an adhesive film, a connection structure, and a method for manufacturing a connection structure.

[0002] Thermosetting resins using epoxy resins that exhibit high adhesiveness and high reliability are known as circuit connecting materials for semiconductor elements and liquid crystal display elements (see, for example, Patent Document 1). The resin components generally used include an epoxy resin, a curing agent such as a phenolic resin that is reactive with the epoxy resin, and a latent curing agent that promotes the reaction between the epoxy resin and the curing agent. The latent curing agent is an important factor that determines the curing temperature and curing rate, and various compounds are used from the viewpoints of storage stability at room temperature and curing rate when heated.

[0003] Recently, radical-curing adhesives that use acrylate derivatives and / or methacrylate derivatives (hereinafter collectively referred to as "(meth)acrylate derivatives") in combination with peroxides, which are radical polymerization initiators, have been attracting attention. Radical curing allows for rapid curing because radicals, which are reactive species, are highly reactive (see, for example, Patent Documents 2 and 3). Therefore, rapid-curing adhesives, which are advantageous for shortening production time, are currently becoming more popular.

[0004] Japanese Patent Application Laid-Open No. 1-113480 Japanese Patent Application Laid-Open No. 2002-203427 International Publication No. 98 / 044067 Pamphlet

[0005] While an adhesive for circuit connection must be able to bond circuit components together with sufficient adhesive strength, it is also desirable for the adhesive to have excellent temporary attachment properties in order to address the following issues. When connecting circuit components together, a process may be employed in which a film-like adhesive is temporarily attached to one circuit component by pressure application, and then the other circuit component is placed in a predetermined position and thermally compressed. In this method, if the adhesive becomes misaligned, rework work may be required, in which the adhesive is peeled off and new adhesive is temporarily attached again. However, if the adhesive's adhesion to the circuit components is too strong, the rework workability may be reduced, and if the adhesion is too weak, problems such as the adhesive falling off during the temporary attachment work may occur.

[0006] Therefore, the present disclosure aims to provide a film-like adhesive that has excellent temporary attachment properties and can exhibit sufficient adhesive strength, an adhesive film that includes the same, and a method for manufacturing a connection structure that uses these, and a connection structure.

[0007] One aspect of the present disclosure relates to the following method for manufacturing a connection structure: [1] A method for manufacturing a connection structure, comprising the steps of laminating an adhesive film on a surface of a first circuit member having a first electrode, on which the first electrode is formed, and placing a second circuit member having a second electrode on the first circuit member laminated with the adhesive film so that the first electrode and the second electrode face each other, and thermocompression bonding them to electrically connect the first electrode and the second electrode to each other, wherein the adhesive film has a film-like adhesive containing a thermoplastic resin and a radically polymerizable compound, and wherein the film-like adhesive has a loss tangent (tan δ) waveform obtained by dynamic viscoelasticity measurement after heating at 170°C for 5 seconds, which waveform has multiple maxima. [2] A method for manufacturing a connection structure according to [1] above, wherein the loss tangent (tan δ) waveform has a maximum value between 40°C and 90°C. [3] A method for producing a connection structure according to [1] or [2] above, wherein the waveform of the loss tangent (tan δ) has two maximum values ​​between 40°C and 100°C, and the difference between the two temperatures showing the maximum values ​​is 20°C or more and 50°C or less. [4] A method for producing a connection structure according to any of [1] to [3] above, wherein the thermoplastic resin contains a polyester urethane resin and a phenoxy resin. [5] A method for producing a connection structure according to any of [1] to [4] above, wherein the radical polymerizable compound contains a (poly)urethane (meth)acrylate compound.

[0008] Another aspect of the present disclosure relates to the following film adhesive and adhesive film. [6] A film adhesive containing a thermoplastic resin and a radically polymerizable compound, wherein the waveform of loss tangent (tan δ) obtained by dynamic viscoelasticity measurement after heating at 170°C for 5 seconds has multiple maxima. [7] The film adhesive according to [6] above, wherein the waveform of loss tangent (tan δ) has a maximum value between 40°C and 90°C. [8] The film adhesive according to [6] or [7] above, wherein the waveform of loss tangent (tan δ) has two maxima between 40°C and 100°C, and the difference between the temperatures showing the two maxima is 20°C or more and 50°C or less. [9] The film adhesive according to any of [6] to [8] above, wherein the thermoplastic resin contains a polyester urethane resin and a phenoxy resin.

[10] The film adhesive according to any of [6] to [9] above, wherein the radically polymerizable compound contains a (poly)urethane (meth)acrylate compound.

[11] The film-like adhesive according to any one of [6] to

[10] above, further containing conductive particles.

[12] An adhesive film comprising the film-like adhesive according to any one of [6] to

[11] above.

[13] The adhesive film according to

[12] above, comprising a first adhesive layer made of the film-like adhesive, and a second adhesive layer made of an adhesive composition containing conductive particles.

[0009] Another aspect of the present disclosure relates to the following connection structure:

[14] A connection structure comprising: a first circuit member having a first electrode, a second circuit member having a second electrode, and a connection portion disposed between the first circuit member and the second circuit member and electrically connecting the first electrode and the second electrode to each other, wherein the connection portion comprises a cured product of the film-like adhesive described in

[12] or

[13] above.

[0010] According to the present disclosure, it is possible to provide a film-like adhesive that has excellent temporary attachment properties and can exhibit sufficient adhesive strength, an adhesive film comprising the same, and a method for manufacturing a connection structure using these, and a connection structure.

[0011] Fig. 4 is a diagram for explaining the waveform of a loss tangent (tan δ). Fig. 5 is a schematic cross-sectional view showing an embodiment of an adhesive film. Fig. 6 is a schematic cross-sectional view showing an embodiment of a connection structure. Fig. 7 is a schematic cross-sectional view showing a method for manufacturing the connection structure of Fig. 3. Fig. 8 is a diagram showing an example of an image obtained by binarizing an image of a temporarily pressure-bonded body photographed with a differential interference microscope.

[0012] In this specification, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range may be replaced with the upper or lower limit of another numerical range. Furthermore, in the numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with a value shown in the examples. Furthermore, the upper and lower limits individually described can be arbitrarily combined. Furthermore, in this specification, "(meth)acrylate" means at least one of acrylate and its corresponding methacrylate. The same applies to other similar expressions such as "(meth)acryloyl". Furthermore, "(poly)" means both with and without the "poly" prefix. Furthermore, "A or B" may include either A or B, or may include both. Furthermore, the materials exemplified below may be used alone or in combination of two or more, unless otherwise specified. When a composition contains multiple substances corresponding to each component, the content of each component in the composition means the total amount of the multiple substances present in the composition, unless otherwise specified.

[0013] Hereinafter, embodiments of the present disclosure will be described in detail, with reference to the drawings as needed. However, the present disclosure is not limited to the following embodiments.

[0014] <Film-like adhesive> The film-like adhesive of this embodiment contains (A) a thermoplastic resin (hereinafter also referred to as "component (A)") and (B) a radically polymerizable compound (hereinafter also referred to as "component (B)"), and the waveform of the loss tangent (tan δ) obtained by dynamic viscoelasticity measurement after heating at 170°C for 5 seconds has multiple maximum values. The film-like adhesive of this embodiment is excellent in temporary attachment and reworkability and can exhibit sufficient adhesive strength. It is presumed that this effect is obtained for the following reason. It is presumed that adhesives exhibiting the above waveform have poor polymer compatibility in the cured product, and that the ability to aggregate the polymer of the radically polymerizable compound, which is likely to provide adhesive strength, into islands makes it possible to ensure sufficient adhesive strength even in a formulation that takes adhesion into consideration.

[0015] The dynamic viscoelasticity measurement can be performed by the following procedure. (i) A pre-heated sample is prepared by laminating a film-like adhesive to a thickness of approximately 100 μm. The thickness of each laminated film-like adhesive can be 5 to 50 μm. (ii) The pre-heated sample prepared in (i) is thermally cured using a thermocompression bonding machine "FCB3" (manufactured by Panasonic Corporation, product name) under conditions of a backup temperature of 90°C, a set pressure of 100 N, an ultimate temperature of 170°C, and a heating time of 5 seconds to prepare a measurement sample. (iii) The measurement sample obtained in (ii) is placed in a dynamic viscoelasticity measuring device "RSA-G2" (manufactured by TA Instruments, product name), and dynamic viscoelasticity measurement is performed under the conditions of tension mode, measurement frequency of 0.1 Hz, strain of 0.1%, heating rate of 10°C / min, and measurement temperature range of 0°C to 200°C.

[0016] The waveform of the loss tangent (tan δ) refers to the relationship between the temperature and the loss tangent (tan δ) obtained by the above measurement. In this disclosure, the terms used for the waveform of the loss tangent (tan δ) are defined as follows. FIG. 1 is a diagram for explaining the waveform of the loss tangent (tan δ). Tan δ peak top: The point where the increase or decrease in tan δ changes from an increase to a decrease (PT in FIG. 1). １ and P.T. ２), and an increase means that tan δ increases continuously by 5°C or more. Tan δ peak bottom: The point where the increase or decrease in tan δ changes from a decrease to an increase (PB in Figure 1). １ ) and "decrease" means that tan δ decreases continuously by 5°C or more. Temperature difference between tan δ peak tops: The difference between the temperature of the tan δ peak top on the high temperature side and the temperature of the tan δ peak top on the low temperature side (D in Figure 1). １ ) means the difference in tan δ between the tan δ peak bottom and the tan δ peak top: the difference between the tan δ at the tan δ peak top with the smaller tan δ and the tan δ at the tan δ peak bottom (D in FIG. 1 ２ ) means

[0017] From the viewpoint of compatibility, the film adhesive of this embodiment may have a loss tangent (tan δ) waveform with two maxima, i.e., bimodal. In this case, from the viewpoint of more clearly defining the peak shape, the tan δ difference (intensity difference) between the tan δ peak bottom and the tan δ peak top may be 0.02 or more, and from the viewpoint of the tan δ waveform being bimodal, the temperature difference between the tan δ peak tops may be within 50°C, or may be 20°C or more and 50°C or less. Furthermore, the temperature of the tan δ peak top on the low-temperature side may be 40°C or more and 70°C or less, and the temperature of the tan δ peak top on the high-temperature side may be 70°C or more and 100°C or less.

[0018] From the viewpoint of storage stability, the film adhesive of this embodiment may have a waveform of loss tangent (tan δ) that has a maximum value between 40°C and 90°C, and from the viewpoints of compatibility and storage stability, the waveform of loss tangent (tan δ) may have two maximum values ​​between 40°C and 100°C, with the difference between the temperatures showing the two maximum values ​​being 20°C or more and 50°C or less.

[0019] Methods for ensuring that the waveform of the loss tangent (tan δ) satisfies the above conditions (e.g., bimodality, the temperature range of the tan δ peak top, the temperature difference between the tan δ peak tops, and the tan δ difference between the tan δ peak bottom and the tan δ peak top) include combining two or more of the following: (i) blending two or more types of component (A) and adjusting their blending ratio; (ii) adjusting the blending ratio of component (A) to component (B). For example, in the case of (ii), the content of component (B) may be adjusted to 70 to 80 parts by mass per 100 parts by mass of component (A). As an example of a combination, for example, the content of component (B) may be adjusted to more than 80 parts by mass per 100 parts by mass of component (A), and the blending ratio of component (A1) to component (A2), described below, [(A1) / (A2)], may be adjusted to be less than 1 / 2.

[0020] The film-like adhesive of this embodiment can be used, for example, as a component constituting an adhesive layer in an adhesive film (adhesive film for circuit connection) used in the following method: A method for manufacturing a connection structure, comprising the steps of: laminating an adhesive film on the surface of a first circuit member having a first electrode (e.g., a first circuit member having a first circuit electrode formed on the main surface of a first substrate) on which the first electrode is formed; and placing a second circuit member having a second electrode (e.g., a second circuit member having a second circuit electrode formed on the main surface of a second substrate) on the first circuit member laminated with the adhesive film so that the first electrode and the second electrode face each other, and thermocompression bonding them together to electrically connect the first electrode and the second electrode to each other.

[0021] [Component (A): Thermoplastic Resin] Component (A) may be one or more resins selected from polyimide resins, polyamide resins, phenoxy resins, poly(meth)acrylic resins, polyester resins, polyurethane resins, polyesterurethane resins, and polyvinyl butyral resins. To facilitate obtaining multiple maximum values ​​in the waveform of the loss tangent (tan δ), two or more of the above thermoplastic resins may be contained, or two or more thermoplastic resins with different Tg's may be contained. Examples of resin combinations include a combination of a phenoxy resin and a poly(meth)acrylic resin, a combination of a phenoxy resin and a polyester resin, a combination of a phenoxy resin and a polyesterurethane resin, and a combination of a phenoxy resin and a polyimide resin.

[0022] The polyester resin may be a polyethylene naphthalate resin from the viewpoint of blending a resin with a higher Tg. The polyethylene naphthalate resin can be obtained by transesterification and polycondensation of a naphthalenedicarboxylic acid ester with diethylene glycol, or by direct polymerization of naphthalenedicarboxylic acid with diethylene glycol. The phenoxy resin can be obtained by reacting a bifunctional phenol with an epihalohydrin to a high molecular weight, or by polyaddition reaction of a bifunctional epoxy resin with a bifunctional phenol.

[0023] The film-like adhesive of the present embodiment may contain a rubber component as component (A). Examples of the rubber component include silicone rubber, acrylic rubber, polyisoprene rubber, polybutadiene rubber, carboxyl-terminated polybutadiene rubber, hydroxyl-terminated polybutadiene rubber, 1,2-polybutadiene rubber, carboxyl-terminated 1,2-polybutadiene rubber, hydroxyl-terminated 1,2-polybutadiene rubber, styrene-butadiene rubber, hydroxyl-terminated styrene-butadiene rubber, acrylonitrile-butadiene rubber, carboxylated nitrile rubber, hydroxyl-terminated poly(oxypropylene) rubber, alkoxysilyl-terminated poly(oxypropylene) rubber, poly(oxytetramethylene) glycol rubber, polyolefin glycol rubber, and poly-ε-caprolactone rubber.

[0024] The film-like adhesive of this embodiment may contain a polyester urethane resin (hereinafter also referred to as "component (A1)") and a phenoxy resin (hereinafter also referred to as "component (A2)") as thermoplastic resins, from the viewpoint of obtaining a resin system with different compatibility.

[0025] From the viewpoint of increasing the tan δ (intensity) of the tan δ peak top on the low temperature side and making it easier to manifest bimodality, the mass ratio of the component (A2) to the component (A1) [(A2) / (A1)] may be 2 or greater and 2.5 or less.

[0026] The weight average molecular weight of the thermoplastic resin may be 5,000 or more or 10,000 or more from the viewpoint of film-forming properties, may be 80,000 or less or 150,000 or less from the viewpoint of adhesive properties, and may be 5,000 to 150,000 or 10,000 to 80,000 from the viewpoint of adhesive properties and film-forming properties. The weight average molecular weight of the thermoplastic resin means the weight average molecular weight (standard polystyrene equivalent value) measured by GPC (gel permeation chromatography).

[0027] In the present disclosure, the thermoplastic resin having a radically polymerizable functional group is blended as the radically polymerizable compound (B).

[0028] From the viewpoint of film formability, the content of component (A) in the film adhesive may be 20% by mass or more or 30% by mass or more, and may be 60% by mass or less or 50% by mass or less, or may be 20 to 60% by mass or 30 to 50% by mass, based on the resin components of the film adhesive (e.g., components other than the conductive particles and filler).

[0029] Furthermore, the content of the (A) component may be 30 parts by mass or more, 40 parts by mass or more, or 50 parts by mass or more, relative to 100 parts by mass of the total amount of the (A) component and the (B) component, and may be 90 parts by mass or less, 70 parts by mass or less, or 60 parts by mass or less, or may be 50 to 60 parts by mass.

[0030] [Component (B): Radically Polymerizable Compound] Component (B) can be a compound having a radically polymerizable functional group. Examples of the radically polymerizable functional group include a vinyl group, an acryloyl group, and a methacryloyl group. Of these, a compound having an acryloyl group and / or a methacryloyl group can be used. Component (B) can be used alone or in combination of two or more types.

[0031] As the component (B), the compounds described below can be used in either a monomeric or oligomeric state, and it is also possible to use a combination of a monomeric and an oligomeric state.

[0032] The component (B) is a polyfunctional (meth)acrylate compound having two or more (meth)acryloyloxy groups.Examples of such (meth)acrylate compounds include epoxy (meth)acrylate, urethane (meth)acrylate, polyether (meth)acrylate, polyester (meth)acrylate, trimethylolpropane tri(meth)acrylate, polyalkylene glycol di(meth)acrylate such as polyethylene glycol di(meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, neopentyl glycol di(meth)acrylate, dipentaerythritol hexa(meth)acrylate, isocyanuric acid-modified bifunctional (meth)acrylate, isocyanuric acid-modified trifunctional (meth)acrylate, etc. Examples of epoxy (meth)acrylates include epoxy (meth)acrylates in which (meth)acrylic acid is added to two glycidyl groups of bisphenol fluorene diglycidyl ether, and compounds in which ethylene glycol and / or propylene glycol are added to two glycidyl groups of bisphenol fluorene diglycidyl ether and a (meth)acryloyloxy group is introduced into the compound. These compounds may be used alone or in combination of two or more.

[0033] Among the above (meth)acrylate compounds, a (poly)urethane(meth)acrylate compound can be used from the viewpoint of obtaining even better adhesiveness by having a urethane bond. From the viewpoint of obtaining even better adhesiveness, the content of the (poly)urethane(meth)acrylate compound may be 30 to 90 mass%, 40 to 80 mass%, or 50 to 70 mass%, based on the total mass of component (B).

[0034] From the viewpoint of improving heat resistance, the component (B) may have at least one partial structure selected from the group consisting of a dicyclopentane skeleton, a tricyclodecane skeleton, and a triazine ring.

[0035] Furthermore, from the viewpoint of further improving heat resistance, component (B) may contain a (meth)acrylate compound having a tricyclodecane skeleton. The content of the (meth)acrylate compound having a tricyclodecane skeleton may be 2 to 20 mass%, 2 to 15 mass%, or 2 to 10 mass%, based on the total mass of component (B).

[0036] From the viewpoint of obtaining even better adhesive properties, the film-like adhesive may contain a monofunctional (meth)acrylate compound as component (B). Examples of the monofunctional (meth)acrylate compound include pentaerythritol (meth)acrylate, 2-cyanoethyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-hexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, isobornyl (meth)acrylate, and isodecyl (meth)acrylate. Examples of the glycidyl group-containing (meth)acrylate include methyl (meth)acrylate, isooctyl (meth)acrylate, n-lauryl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-(meth)acryloyloxyethyl phosphate, N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, glycidyl group-containing (meth)acrylate obtained by reacting one of the glycidyl groups of an epoxy resin having multiple glycidyl groups with (meth)acrylic acid, and (meth)acryloylmorpholine. These compounds may be used alone or in combination of two or more.

[0037] From the viewpoint of obtaining even better adhesive properties, the film adhesive may contain, as component (B), a compound having a radically polymerizable functional group such as an allyl group, a maleimide group, a vinyl group, etc. Examples of such compounds include N-vinylimidazole, N-vinylpyridine, N-vinylpyrrolidone, N-vinylformamide, N-vinylcaprolactam, 4,4'-vinylidenebis(N,N-dimethylaniline), N-vinylacetamide, N,N-dimethylacrylamide, N-isopropylacrylamide, and N,N-diethylacrylamide.

[0038] For the purpose of improving adhesive strength, the film adhesive may contain a radical polymerizable compound having a phosphate ester structure as component (B). The radical polymerizable compound having a phosphate ester structure may be, for example, a compound represented by the following formula (1), (2), or (3): In formula (1), R １ represents a hydrogen atom or a methyl group, R ２ represents a (meth)acryloyloxy group, and a and b each independently represent an integer of 1 to 8. １ , R ２ , a and b may be the same or different from each other.

[0039] In formula (2), R ３ represents a (meth)acryloyloxy group, and c and d each independently represent an integer of 1 to 8. ３ , c and d may be the same or different from each other.

[0040] In formula (3), R ４ represents a hydrogen atom or a methyl group, R ５ represents a (meth)acryloyloxy group, and e and f each independently represent an integer of 1 to 8. ４ , R ４ , e and f may be the same or different from each other.

[0041] Examples of radical polymerizable compounds having a phosphate ester structure include acid phosphooxyethyl (meth)acrylate, acid phosphooxypropyl (meth)acrylate, acid phosphooxypolyoxyethylene glycol mono(meth)acrylate, acid phosphooxypolyoxypropylene glycol mono(meth)acrylate, 2,2'-di(meth)acryloyloxydiethyl phosphate, EO (ethylene oxide)-modified phosphate di(meth)acrylate, phosphate-modified epoxy (meth)acrylate, and vinyl phosphate.

[0042] The content of component (B) in the film-like adhesive may be 10 parts by mass or more, 30 parts by mass or more, or 40 parts by mass or more, relative to 100 parts by mass of the total amount of component (A) and component (B), and may be 70 parts by mass or less, 60 parts by mass or less, or 50 parts by mass or less, or may be 40 to 50 parts by mass.

[0043] From the viewpoint of making the waveform of the loss tangent (tan δ) bimodal, the ratio of the content of the component (B) to the content of the component (A) [(B) / (A)] may be 0.7 to 0.8, and when (B) / (A) exceeds 0.8, the mass ratio of the component (A2) to the component (A1) [(A2) / (A1)] can be 2 or greater.

[0044] When the film-like adhesive contains a radically polymerizable compound having a phosphate ester structure as component (B), the content of the radically polymerizable compound having a phosphate ester structure may be 1 part by mass or more, or may be 100 parts by mass or less, 50 parts by mass or less, or 10 parts by mass or less, relative to 100 parts by mass of the total amount of components (a) and (b).

[0045] The film-like adhesive of this embodiment may further contain at least one of (C) a radical polymerization initiator (hereinafter also referred to as "component (C)"), (D) a filler (hereinafter also referred to as "component (D)"), (E) a silane coupling agent (hereinafter also referred to as "component (E)"), and (F) conductive particles (hereinafter also referred to as "component (F)").

[0046] [Component (C): Radical Polymerization Initiator] The component (C) can be arbitrarily selected from compounds such as peroxides and azo compounds. From the viewpoint of excellent stability, reactivity, and compatibility, a peroxide having a one-minute half-life temperature of 90°C to 175°C and a molecular weight of 180 to 1,000 is preferably used as the component (C). The "one-minute half-life temperature" refers to the temperature at which the half-life of the peroxide is one minute. The "half-life" refers to the time required for the concentration of a compound to decrease to half of its initial value at a given temperature.

[0047] Examples of the radical polymerization initiator include 1,1,3,3-tetramethylbutyl peroxyneodecanoate, di(4-t-butylcyclohexyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, cumyl peroxyneodecanoate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, dilauroyl peroxide, 1-cyclohexyl-1-methylethyl peroxyneodecanoate, t-hexyl peroxyneodecanoate, t-butyl peroxyneodecanoate, and t- Butyl peroxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyneoheptanoate, t-amylperoxy-2-ethylhexanoate, di-t-butylperoxyhexahydroterephthalate, t-amylperoxy-3,5,5-trimethylhexanoate, 3 -Hydroxy-1,1-dimethylbutylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-amylperoxyneodecanoate, t-amylperoxy-2-ethylhexanoate, 3-methylbenzoyl peroxide, 4-methylbenzoyl peroxide, di(3-methylbenzoyl) peroxide, dibenzoyl peroxide, di(4-methylbenzoyl) peroxide, 2,2'-azobis-2,4-dimethylvaleronitrile, 1,1'-azobis (1-acetoxy-1-phenylethane), 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), dimethyl-2,2'-azobisisobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), 1,1'-azobis(1-cyclohexanecarbonitrile), t-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2,5-dimethyl-2,The compound may be one or more compounds selected from 5-di(3-methylbenzoylperoxy)hexane, t-butylperoxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butyl peroxybenzoate, dibutyl peroxytrimethyl adipate, t-amyl peroxy normal octoate, t-amyl peroxy isononanoate, and t-amyl peroxybenzoate.

[0048] The content of component (C) in the film adhesive may be 1 part by mass or more, or 2.5 parts by mass or more, and may be 15 parts by mass or less, 10 parts by mass or less, or 5 parts by mass or less, relative to 100 parts by mass of the total amount of components (A) and (B).

[0049] [Component (D): Filler] The filler may be particles composed of silicon, calcium, zirconium, titanium, aluminum, carbon, bismuth, cobalt, copper, iron, indium, manganese, tin, yttrium, zinc, etc., or compounds containing these elements, organic compounds, etc. The average particle size of the particles is, for example, 0.005 μm to 25 μm.

[0050] The content of component (D) in the film adhesive may be 1 part by mass or more, or 5 parts by mass or more, and may be 30 parts by mass or less, 25 parts by mass or less, or 20 parts by mass or less, relative to 100 parts by mass of the total amount of components (A) and (B).

[0051] [Component (E): Silane Coupling Agent] Examples of silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, and condensates thereof.

[0052] The content of component (E) in the film adhesive may be 0.1 parts by mass or more, 0.2 parts by mass or more, or 0.25 parts by mass or more, and may be 10 parts by mass or less, or 5 parts by mass or less, relative to 100 parts by mass of the total amount of components (A) and (B).

[0053] [Component (F): Conductive Particles] Examples of component (F) include metal particles such as Au, Ag, Ni, Cu, and solder, and conductive particles such as conductive carbon particles. The conductive particles may be coated conductive particles comprising a core made of non-conductive glass, ceramic, plastic, or other particles, and a layer of the above-mentioned metal, metal particles, conductive carbon particles, or the like, covering the core. The conductive particles may be insulating-coated conductive particles comprising the above-mentioned conductive particles and an insulating coating layer formed of an insulating material such as a polymer resin, which coats the surface of the conductive particles, from the viewpoint of preventing short-circuiting between the conductive particles and improving insulation between adjacent circuit electrodes, particularly when the amount of conductive particles is increased. These conductive particles, coated conductive particles, and insulating-coated conductive particles may be used alone or in combination of two or more.

[0054] The average particle size of the conductive particles may be 1 μm to 50 μm from the viewpoint of excellent dispersibility and conductivity. The content of the conductive particles may be 0.1 vol% or more, 30 vol% or less, or 10 vol% or less, based on the total volume of the film-like adhesive. The content of the conductive particles is determined based on the volume of each component of the adhesive (before curing) at 23°C. The volume of each component can be calculated by converting weight to volume using specific gravity, for example. Alternatively, the volume can be calculated by adding a component to a measuring cylinder or the like containing an appropriate solvent (water, alcohol, etc.) that thoroughly wets the component without dissolving or swelling the component, and then measuring the increased volume.

[0055] The film adhesive of this embodiment may contain other additives such as other resins such as phenolic resins and melamine resins, softeners, curing accelerators, antioxidants, colorants, flame retardants, thixotropic agents, adhesion improvers, thickeners, leveling agents, weather resistance improvers, polymerization inhibitors, etc. Examples of polymerization inhibitors include hydroquinone and methyl ether hydroquinones.

[0056] The film-like adhesive of this embodiment can be produced by the following method. Specifically, first, the above-mentioned components, and other components added as needed, are added to a solvent (organic solvent), and dissolved or dispersed by stirring, mixing, kneading, etc. to prepare a varnish composition (varnish-like adhesive composition). Thereafter, the varnish composition is applied to a release-treated substrate using a knife coater, roll coater, applicator, comma coater, die coater, etc., and the solvent is volatilized by heating, thereby forming a film-like adhesive on the substrate.

[0057] The solvent used in preparing the varnish composition may be a solvent capable of uniformly dissolving or dispersing each component. Examples of such solvents include toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, and butyl acetate. These solvents can be used alone or in combination of two or more. The stirring, mixing, and kneading in preparing the varnish composition can be performed using, for example, a mixer, a grinder, a three-roll mill, a ball mill, a bead mill, or a homodisper.

[0058] The substrate is not particularly limited as long as it has heat resistance sufficient to withstand the heating conditions when volatilizing the solvent, and for example, substrates (e.g., films) made of oriented polypropylene (OPP), polyethylene terephthalate (PET), polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, polyimide, cellulose, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, synthetic rubber, liquid crystal polymer, etc. can be used.

[0059] The heating conditions for volatilizing the solvent from the varnish composition applied to the substrate may be conditions that allow the solvent to volatilize sufficiently, such as a temperature of 40°C or higher and 120°C or lower for 0.1 minutes or longer and 10 minutes or shorter.

[0060] In the film adhesive of this embodiment, some of the solvent may remain unremoved. The content of the solvent in the film adhesive of this embodiment may be, for example, 10 mass % or less, or 5 mass % or less, based on the total mass of the film adhesive.

[0061] From the viewpoint of temporary attachment properties, the film adhesive of this embodiment may have an adhesion rate of 45 to 60% as measured by the following method: 1. A film adhesive slit to a width of 1.2 mm is applied to a 0.7 mm thick SiN ｘ A substrate (a glass substrate and a silicon nitride (SiN) layer having a thickness of 0.2 μm formed on the glass substrate) ｘ) and three silicone films (200 μm thick) are placed on the adhesive. 2.1. Following step 2, the film-like adhesive is temporarily bonded to the glass at 70°C, 1 MPa, and 1 second to obtain a temporarily bonded body. 3. The temporarily bonded body is photographed from the glass side using a differential interference microscope "ECLIPSE L300" (manufactured by Nikon Corporation). 4. The photographed image is trimmed and binarized using a homemade program (programming language: Python, OpenCV (Intel, module name) used for image processing). The trimming process is performed so that only the area where the film-like adhesive is in contact with the adherend, the glass, remains, and the binarization process is performed so that the area where the glass and the adhesive are in close contact becomes black. 5. Based on the binarized image, the area ratio of the black area is calculated using the following formula, and this is the adhesion rate. Black area ratio (%) = [(number of pixels in black area) x 100] / (number of pixels in the entire image)

[0062] If the adhesion rate is 45% or more, the adhesive is less likely to come off during the temporary attachment work, and if the adhesion rate is 60% or less, if the adhesive becomes misaligned during the temporary attachment work, rework work can be easily performed by peeling off the adhesive and temporarily attaching new adhesive again.

[0063] <Adhesive Film> The adhesive film of this embodiment includes the film-like adhesive of this embodiment described above.

[0064] Fig. 2 is a schematic cross-sectional view showing an adhesive film according to one embodiment. As shown in Fig. 2, in one embodiment, adhesive film 1 is composed of a single layer made of adhesive component 2 and conductive particles 3 dispersed in adhesive component 2. In one embodiment, adhesive component 2 contains the above-mentioned components (A) and (B), as well as other components such as components (C) to (E).

[0065] The adhesive film 1 may be in an uncured state or in a partially cured state.

[0066] The thickness of the adhesive film 1 may be, for example, 3 μm or more or 10 μm or more, and may be 30 μm or less or 20 μm or less.

[0067] In one embodiment, the adhesive film of this embodiment may have a multilayer structure including a first adhesive layer made of a film-like adhesive and a second adhesive layer made of an adhesive composition containing conductive particles. The conductive particles and adhesive composition constituting the second adhesive layer may be formed from the same components as those of the film-like adhesive of this embodiment described above.

[0068] The adhesive film may be an anisotropically conductive adhesive film (anisotropically conductive film), or may be a conductive adhesive film that does not have anisotropic conductivity.

[0069] <Connection Structure> Another embodiment of the present disclosure is a connection structure comprising: a first circuit member having a first electrode; a second circuit member having a second electrode; and a connection portion disposed between the first circuit member and the second circuit member and electrically connecting the first electrode and the second electrode to each other, wherein the connection portion includes a cured product of the above-described film-like adhesive.

[0070] 3 is a schematic cross-sectional view showing one embodiment of a connection structure 10. As shown in FIG. 3, the connection structure 10 includes a first circuit member 4 and a second circuit member 5 facing each other, and a connection portion 6 that connects the first circuit member 4 and the second circuit member 5 between the first circuit member 4 and the second circuit member 5.

[0071] The first circuit member 4 includes a first circuit board 41 and a first electrode 42 formed on a main surface 41 a of the first circuit board 41. The second circuit member 5 includes a second circuit board 51 and a second electrode 52 formed on a main surface 51 a of the second circuit board 51.

[0072] There are no particular limitations on the first circuit member 4 and the second circuit member 5 as long as they are members on which electrodes that require electrical connection are formed. Examples of members on which electrodes are formed (circuit members, etc.) include inorganic substrates such as semiconductors, glass, and ceramics; polyimide substrates such as TCP, FPC, and COF; substrates on which electrodes are formed on films such as polycarbonate, polyester, and polyethersulfone; and printed wiring boards, and a combination of these may also be used.

[0073] The connection portion 6 includes a cured product of the film-like adhesive, and contains an insulating material 7, which is a cured product of the adhesive component, and conductive particles 3. The conductive particles 3 may be disposed not only between the opposing first electrode 42 and second electrode 52, but also between the main surface 41 a of the first circuit board 41 and the main surface 51 a of the second circuit board 51. In the connection structure 10, the first electrode 42 and the second electrode 52 are electrically connected via the conductive particles 3. That is, the conductive particles 3 are in contact with both the first electrode 42 and the second electrode 52.

[0074] In the connection structure 10, the opposing first electrode 42 and second electrode 52 are electrically connected via conductive particles 3, but if the film-like adhesive does not contain conductive particles, the first electrode 42 and second electrode 52 may be in direct contact.

[0075] <Method for manufacturing connection structure> Another embodiment of the present disclosure is a method for manufacturing a connection structure, comprising the steps of: laminating the adhesive film of the present embodiment described above on a surface of a first circuit member having a first electrode, the surface on which the first electrode is formed; and arranging a second circuit member having a second electrode on the first circuit member laminated with the adhesive film so that the first electrode and the second electrode face each other, and thermocompression bonding them to electrically connect the first electrode and the second electrode to each other.

[0076] 4 is a schematic cross-sectional view showing one embodiment of a method for manufacturing a connection structure. As shown in FIG. 4( a), first, a first circuit member 4 and an adhesive film 1 are prepared. Next, the adhesive film 1 is laminated onto the main surface 41 a of the first circuit member 4. When the adhesive film 1 is laminated on a substrate (not shown), the laminate is laminated onto the first circuit member 4 with the adhesive film 1 side of the substrate facing the first circuit member 4. When the adhesive film 1 has a multilayer structure including a first adhesive layer made of a film-like adhesive and a second adhesive layer made of an adhesive composition containing conductive particles, it is preferable to laminate the first adhesive layer side so that it contacts the main surface 41 a of the first circuit member 4.

[0077] In this embodiment, pressure may be applied in the directions of arrows A and B in Fig. 4(a) to temporarily attach the adhesive film 1 and the first circuit member 4 (see Fig. 4(b)). At this time, heat may be applied together with the pressure.

[0078] 4(c), the second circuit member 5 is further placed on the adhesive film 1 temporarily attached to the first circuit member 4, with the second electrode 52 facing the first circuit member 4 (i.e., the first electrode 42 and the second electrode 52 are arranged opposite each other, with the adhesive film 1 interposed between the first circuit member 4 and the second circuit member 5). If the adhesive film 1 is laminated on a substrate (not shown), the substrate is peeled off and then the second circuit member 5 is placed on the adhesive film 1.

[0079] These are then thermocompressed in the directions of arrows A and B in Figure 4(c), thereby hardening the adhesive film 1 and achieving a permanent connection that electrically connects the first electrode 42 and the second electrode 52 to each other. As a result, a connection structure 10 as shown in Figure 3 is obtained.

[0080] According to the method for manufacturing a connection structure of this embodiment, the adhesive film has excellent temporary attachment properties and contains a film-like adhesive that can exhibit sufficient adhesive strength, so that connection structures can be manufactured efficiently. Furthermore, even if rework work such as re-temporary attachment is required, the adhesive can be peeled off with good workability.

[0081] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0082] <Synthesis of Polyester Urethane Resin (A1)> 48 parts by mass of isophthalic acid and 37 parts by mass of neopentyl glycol were added to a heated stainless steel autoclave equipped with a stirrer, thermometer, condenser, vacuum generator, and nitrogen gas inlet tube, and 0.02 parts by mass of tetrabutoxy titanate as a catalyst was further added. Next, the temperature was raised to 220 ° C. under a nitrogen stream and stirred for 8 hours. Then, the pressure was reduced to atmospheric pressure (760 mmHg) and cooled to room temperature. This resulted in the precipitation of a white precipitate. Next, the white precipitate was removed, washed with water, and vacuum dried to obtain a polyester polyol. After thoroughly drying the obtained polyester polyol, it was dissolved in MEK (methyl ethyl ketone) and added to a four-neck flask equipped with a stirrer, a dropping funnel, a reflux condenser, and a nitrogen gas inlet tube. Furthermore, dibutyltin dilaurate was added as a catalyst in an amount of 0.05 parts by mass per 100 parts by mass of polyester polyol, and 4,4'-diphenylmethane diisocyanate was dissolved in MEK in an amount of 50 parts by mass per 100 parts by mass of polyester polyol and added using a dropping funnel. The mixture was stirred at 80°C for 4 hours to obtain the desired polyester urethane resin. The weight-average molecular weight of the polyester urethane resin was 15,000. The weight-average molecular weight was measured by gel permeation chromatography (GPC) using a calibration curve based on standard polystyrene under the following conditions. (Measurement Conditions) Apparatus: GPC-8020 manufactured by Tosoh Corporation Detector: RI-8020 manufactured by Tosoh Corporation Column: Gelpack GLA160S + GLA150SG2000Hhr manufactured by Resonaq Co., Ltd. Solvent: Tetrahydrofuran Injection volume: 60 μL Pressure: 2.94 × 10 ６ Pa flow rate: 1.00mL / min

[0083] <Synthesis of Polyurethane Acrylate B1> A 2 L (liter) four-neck flask equipped with a thermometer, a stirrer, an inert gas inlet, and a reflux condenser was charged with 4,000 parts by mass of polycarbonate diol (manufactured by Aldrich, number average molecular weight 2,000), 238 parts by mass of 2-hydroxyethyl acrylate, 0.49 parts by mass of hydroquinone monomethyl ether, and 4.9 parts by mass of a tin-based catalyst to prepare a reaction solution. 666 parts by mass of isophorone diisocyanate (IPDI) was uniformly added dropwise to the reaction solution heated to 70°C over 3 hours to allow the reaction to proceed. After completion of the addition, the reaction was continued for 15 hours, and the reaction was deemed to have ended when the NCO% (NCO content) reached 0.2% by mass or less, yielding a urethane acrylate. The NCO% was confirmed using an automatic potentiometric titrator (trade name: AT-510, manufactured by Kyoto Electronics Manufacturing Co., Ltd.). Analysis by GPC revealed that the weight-average molecular weight of the urethane acrylate was 8,500 (standard polystyrene equivalent). The weight-average molecular weight was measured by gel permeation chromatography (GPC) using a calibration curve based on standard polystyrene under the following conditions: (Measurement conditions) Apparatus: GPC-8020 manufactured by Tosoh Corporation Detector: RI-8020 manufactured by Tosoh Corporation Column: Gelpack GLA160S + GLA150S manufactured by Resonaq Corporation Sample concentration: 120 mg / 3 mL Solvent: Tetrahydrofuran Injection volume: 60 μL Pressure: 2.94 × 10 ６ Pa (30kgf / cm ２ ) Flow rate: 1.00mL / min

[0084] [Preparation of Film-Like Adhesive] (Examples 1 to 3, Comparative Examples 1 to 4) The components shown below were mixed in the amounts (parts by mass) shown in Table 1 to prepare varnish compositions.

[0085] (Thermoplastic resin) A1: Polyester urethane resin (A1) synthesized as described above. A2: A 40% by mass solution prepared by dissolving 40 g of bisphenol A phenoxy resin (trade name: PKHC, manufactured by Union Carbide Corporation) in 60 g of methyl ethyl ketone was used (the blending amount in the table indicates the blending amount of bisphenol A phenoxy resin).

[0086] (Radical polymerizable compounds) B1: Polyurethane acrylate (UA1) synthesized as described above B2: Isocyanuric acid EO-modified diacrylate (trade name: M-215, manufactured by Toa Gosei Co., Ltd.) B3: Diacrylate having a tricyclodecane skeleton (dicyclopentadiene type diacrylate) (trade name: DCP-A, manufactured by Kyoeisha Chemical Co., Ltd.) B4: Pentaerythritol tetrakis(3-mercaptobutyrate) (trade name: Karenz MT PE-1 ("Karenz MT" is a registered trademark), manufactured by Resonac Corporation) B5: 2-methacryloyloxyethyl acid phosphate (trade name: Light Ester P-2M, manufactured by Kyoeisha Chemical Co., Ltd.)

[0087] (Radical polymerization initiator) C1: Benzoyl peroxide (trade name: Niper BMT-K40, manufactured by NOF Corporation) C2: Lauroyl peroxide (trade name: Perloyl L, manufactured by NOF Corporation)

[0088] (Filler) D1: Silica fine particles (product name: R104, manufactured by Nippon Aerosil Co., Ltd., average particle size (primary particle size): 12 nm)

[0089] (Coupling Agent) E1: 3-methacryloxypropyltrimethoxysilane (trade name: KBM503, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0090] The varnish composition obtained above was applied to a 50 μm-thick PET film using a coating device, followed by hot air drying at 70° C. for 3 minutes to form a film-like adhesive having a thickness (thickness after drying) of 8.5 μm on the PET film.

[0091] [Evaluation of Film Adhesive] For the film adhesives produced in the Examples and Comparative Examples, the waveform of the loss tangent (tan δ) was evaluated, adhesion was measured and evaluated, and adhesive strength was measured according to the methods described below.

[0092] <Evaluation of the Waveform of Loss Tangent (tan δ)> First, the waveform of the loss tangent (tan δ) was obtained by performing dynamic viscoelasticity measurement on the film adhesive using the following procedure. (i) The film adhesive was laminated to a thickness of approximately 100 μm to prepare a pre-heated sample. (ii) The pre-heated sample prepared in (i) was thermally cured using a thermocompression bonding machine "FCB3" (manufactured by Panasonic, product name) under conditions of a backup temperature of 90°C, a set pressure of 100 N, an ultimate temperature of 170°C, and a heating time of 5 seconds to prepare a measurement sample. (iii) The measurement sample obtained in (ii) was placed in a dynamic viscoelasticity measuring device "RSA-G2" (manufactured by TA Instruments, product name), and dynamic viscoelasticity was measured under the conditions of tension mode, measurement frequency of 0.1 Hz, strain of 0.1%, heating rate of 10°C / min, and measurement temperature range of 0°C to 200°C.

[0093] Next, the number of tan δ peak tops and the presence or absence of tan δ peak bottoms were confirmed for the waveform of loss tangent (tan δ) obtained by the above dynamic viscoelasticity measurement, and based on these, the temperature difference between the tan δ peak tops and the tan δ difference between the tan δ peak bottom and the tan δ peak top were calculated.

[0094] <Measurement of Adhesion Ratio> The adhesion ratio of the film-like adhesive was determined by the following procedure: 1. A film-like adhesive slit to a width of 1.2 mm was placed on a 0.7 mm thick SiN ｘ A substrate (a glass substrate and a silicon nitride (SiN) layer having a thickness of 0.2 μm formed on the glass substrate) ｘ) and three silicone films (200 μm thick) are placed on the adhesive. 2.1. Following step 2, the film-like adhesive is temporarily bonded to the glass at 70°C, 1 MPa, and 1 second to obtain a temporarily bonded body. 3. The temporarily bonded body is photographed from the glass side using a differential interference microscope "ECLIPSE L300" (manufactured by Nikon Corporation). 4. The photographed image is trimmed and binarized using a homemade program (programming language: Python, OpenCV (manufactured by Intel, module name) used for image processing). The trimming process is performed so that only the area where the film-like adhesive is in contact with the adherend, the glass, remains, and the binarization process is performed so that the area where the glass and the adhesive are in close contact becomes black. FIG. 5 shows an example of a binarized image of a temporarily bonded body photographed using a differential interference microscope. 5. Based on the binarized image, the area ratio of the black portion is calculated using the following formula, and this is taken as the adhesion ratio: Area ratio of black portion (%) = [(number of pixels in the black portion) x 100] / (number of pixels in the entire image)

[0095] <Evaluation of Adhesion Rate> When the adhesion rate measured above is within the range of 45% to 60%, good tackiness and reworkability can be obtained. When the adhesion rate is less than 45%, tackiness becomes difficult, and when the adhesion rate exceeds 60%, reworkability deteriorates.

[0096] <Measurement of Adhesive Strength> The adhesive strength of the film-like adhesive was measured according to the following method.

[0097] A 25 μm pitch COF (manufactured by FLEXSEED) and a glass substrate (manufactured by Geomatec Co., Ltd.) with thin-film electrodes (height: 1200 Å) made of silicon nitride (SiNx) on the glass substrate were connected via the prepared film-like adhesive over a width of 1 mm by heating and pressing at 180°C and 4.5 MPa for 4 seconds using a thermocompression bonding device (heating method: constant heat type, manufactured by Taiyo Kikai Seisakusho Co., Ltd.), to produce a circuit connection structure (connection structure). The adhesive strength of the obtained circuit connection structure at room temperature immediately after connection was measured using a Tensilon UTM-4 (manufactured by Toyo Baldwin Co., Ltd., peel strength 50 mm / min).

[0098]

[0099] 1...adhesive film, 2...adhesive component, 3...conductive particles, 4...first circuit member, 5...second circuit member, 6...connection portion, 7...insulating material, 10...connection structure, 41...first circuit board, 42...first electrode, 51...second circuit board, 52...second electrode.

Claims

1. A method for manufacturing a connection structure, comprising the steps of: laminating an adhesive film on a surface of a first circuit member having a first electrode on which the first electrode is formed; and arranging a second circuit member having a second electrode on the first circuit member laminated with the adhesive film so that the first electrode and the second electrode face each other, and thermocompression bonding them to electrically connect the first electrode and the second electrode to each other, wherein the adhesive film has a film-like adhesive containing a thermoplastic resin and a radically polymerizable compound, and the film-like adhesive has a waveform of loss tangent (tan δ) that has multiple maxima obtained by dynamic viscoelasticity measurement after heating at 170°C for 5 seconds.

2. The method for manufacturing a connection structure according to claim 1, wherein the waveform of the loss tangent (tan δ) has a maximum value between 40°C and 90°C.

3. A method for manufacturing a connection structure as described in claim 1 or 2, wherein the waveform of the loss tangent (tan δ) has two maximum values ​​between 40°C and 100°C, and the difference between the temperatures showing the two maximum values ​​is 20°C or more and 50°C or less.

4. A method for manufacturing a connection structure according to claim 1 or 2, wherein the thermoplastic resin contains polyester urethane resin and phenoxy resin.

5. A method for producing a connection structure according to claim 1 or 2, wherein the radical polymerizable compound contains a (poly)urethane (meth)acrylate compound.

6. A film-like adhesive containing a thermoplastic resin and a radically polymerizable compound, in which the waveform of loss tangent (tan δ) obtained by dynamic viscoelasticity measurement after heating at 170°C for 5 seconds has multiple maximum values.

7. The film adhesive according to claim 6, wherein the waveform of the loss tangent (tan δ) has a maximum value between 40°C and 90°C.

8. The film-like adhesive according to claim 6, wherein the waveform of the loss tangent (tan δ) has two maximum values ​​between 40°C and 100°C, and the difference between the temperatures showing the two maximum values ​​is 20°C or more and 50°C or less.

9. The film adhesive according to claim 6, wherein the thermoplastic resin contains a polyester urethane resin and a phenoxy resin.

10. The film-like adhesive according to claim 6, wherein the radically polymerizable compound contains a (poly)urethane (meth)acrylate compound.

11. The film adhesive according to claim 6, further comprising conductive particles.

12. An adhesive film comprising the film-like adhesive according to any one of claims 6 to 11.

13. The adhesive film according to claim 12, comprising a first adhesive layer made of the film-like adhesive, and a second adhesive layer made of an adhesive composition containing conductive particles.

14. A connection structure comprising: a first circuit member having a first electrode; a second circuit member having a second electrode; and a connection portion disposed between the first circuit member and the second circuit member and electrically connecting the first electrode and the second electrode to each other, wherein the connection portion comprises a cured product of the film-like adhesive according to claim 12.

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