Film-shaped adhesive, adhesive film, connection structure, and method for manufacturing connection structure

Abstract

A method for manufacturing a connection structure, including: a step of laminating an adhesive film on a surface of a first circuit member having a first electrode, the surface being formed with the first electrode; and a step of disposing a second circuit member having a second electrode on the first circuit member on which the adhesive film is laminated, so that the first electrode and the second electrode face each other, and thermocompression bonding them, thereby electrically connecting the first electrode and the second electrode to each other, the adhesive film having a film-shaped adhesive containing a thermoplastic resin and a radical polymerizable compound, a waveform of a loss tangent (tan δ) obtained by dynamic viscoelasticity measurement after heating the film-shaped adhesive at 170°C for 5 seconds having a plurality of maximum values.

Description

Technical Field

[0001] This disclosure relates to a film-like adhesive, an adhesive film, a connecting structure, and a method for manufacturing the connecting structure. Background Technology

[0002] As circuit connection materials for semiconductor elements or liquid crystal display elements, thermosetting resins using epoxy resins that exhibit high adhesion and high reliability are known (for example, see Patent Document 1). As components of the resin, epoxy resin, curing agents such as phenolic resins that react with epoxy resin, and latent curing agents that promote the reaction between the epoxy resin and the curing agent are typically used. The latent curing agent becomes an important factor in determining the curing temperature and curing speed, and various compounds are used from the viewpoint of storage stability at room temperature and curing speed upon heating.

[0003] Furthermore, in recent years, there has been a focus on free radical curing adhesives that simultaneously utilize acrylate derivatives and / or methacrylate derivatives (hereinafter collectively referred to as "(meth)acrylate derivatives") with peroxides as free radical polymerization initiators. Since free radicals, as reactive species, are highly reactive, free radical curing can be achieved through short-time curing (see, for example, Patent Documents 2 and 3). Therefore, short-time curing adhesives, which are advantageous for reducing production time, are currently gaining popularity.

[0004] Previous technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 1-113480

[0007] Patent Document 2: Japanese Patent Application Publication No. 2002-203427

[0008] Patent Document 3: International Publication No. 98 / 044067 Summary of the Invention

[0009] The technical problem to be solved by the invention

[0010] However, adhesives used for circuit connections need to be able to bond circuit components together with sufficient adhesive force, but excellent temporary fixation is also desirable as well. When connecting circuit components, the following process is sometimes used: after temporarily fixing one circuit component by pressing a film-like adhesive onto it, the other circuit component is positioned in a predetermined location and then heat-pressed together. In this method, rework may sometimes occur, where, in cases of adhesive misalignment, the adhesive is peeled off and a new adhesive is temporarily applied. However, if the adhesive's adhesion to the circuit components is too high, the workability for rework decreases; if the adhesion is too low, problems such as adhesive detachment during temporary fixation are likely to occur.

[0011] Therefore, the purpose of this disclosure is to provide a film-like adhesive with excellent temporary fixation and sufficient adhesive force, an adhesive film having the film-like adhesive, a method for manufacturing a connection structure using the same, and a connection structure thereof.

[0012] means for solving technical problems

[0013] One aspect of this disclosure relates to a method for manufacturing the following connection structure.

[0014] [1] A method for manufacturing a connecting structure, comprising:

[0015] The process of laminating an adhesive film onto the surface of a first circuit component having a first electrode on which the first electrode is formed; and

[0016] The process of placing a second circuit component having a second electrode on a first circuit component laminated with the adhesive film, such that the first electrode and the second electrode are facing each other, and then heat-pressing them together to electrically connect the first electrode and the second electrode to each other.

[0017] The adhesive film has a film-like adhesive containing thermoplastic resin and free radical polymerizable compounds.

[0018] The waveform of the loss tangent (tanδ) obtained by dynamic viscoelasticity measurement after heating the film adhesive at 170°C for 5 seconds has multiple maxima.

[0019] [2] According to the manufacturing method of the connecting structure described in [1] above, wherein,

[0020] The waveform of the loss tangent (tanδ) has a maximum value between 40℃ and 90℃.

[0021] [3] According to the manufacturing method of the connecting structure described in [1] or [2] above, wherein,

[0022] The waveform of the loss tangent (tanδ) has two maxima between 40℃ and 100℃, indicating that the temperature difference between the two maxima is above 20℃ and below 50℃.

[0023] [4] The manufacturing method of the connecting structure according to any one of [1] to [3] above, wherein,

[0024] The thermoplastic resin contains polyester polyurethane resin and phenoxy resin.

[0025] [5] The manufacturing method of the connecting structure according to any one of [1] to [4] above, wherein,

[0026] The free radical polymerizable compound contains (poly)urethane (meth)acrylate compounds.

[0027] Furthermore, one aspect of this disclosure relates to a film-like adhesive and an adhesive film.

[0028] [6] A film-like adhesive comprising a thermoplastic resin and a free radical polymerizable compound, wherein,

[0029] The waveform of the loss tangent (tanδ) obtained by dynamic viscoelasticity measurement after heating at 170°C for 5 seconds has multiple maxima.

[0030] [7] According to the film adhesive described in [6] above, wherein,

[0031] The waveform of the loss tangent (tanδ) has a maximum value between 40℃ and 90℃.

[0032] [8] According to the film adhesive described in [6] or [7] above, wherein,

[0033] The waveform of the loss tangent (tanδ) has two maxima between 40℃ and 100℃, indicating that the temperature difference between the two maxima is above 20℃ and below 50℃.

[0034] [9] The film adhesive according to any one of [6] to [8] above, wherein,

[0035] The thermoplastic resin contains polyester polyurethane resin and phenoxy resin.

[0036]

[10] The film adhesive according to any one of [6] to [9] above, wherein,

[0037] The free radical polymerizable compound contains (poly)urethane (meth)acrylate compounds.

[0038]

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

[10] above further contains conductive particles.

[0039]

[12] An adhesive film comprising any one of the film-like adhesives described in any one of [6] to

[11] .

[0040]

[13] The adhesive film according to

[12] above comprises:

[0041] The first adhesive layer is formed of the film-like adhesive; and

[0042] The second adhesive layer is formed of an adhesive composition containing conductive particles.

[0043] Furthermore, one aspect of this disclosure relates to the following connection structure.

[0044]

[14] A connecting structure comprising:

[0045] The first circuit component has a first electrode;

[0046] The second circuit component has a second electrode; and

[0047] A connecting portion is disposed between the first circuit component and the second circuit component, and electrically connects the first electrode and the second electrode to each other.

[0048] The connecting portion comprises a cured product of the film adhesive described in

[12] or

[13] .

[0049] Invention Effects

[0050] According to this disclosure, a film-like adhesive with excellent temporary fixation and sufficient adhesive force can be provided, as well as an adhesive film having the film-like adhesive, a method for manufacturing a connecting structure using the same, and a connecting structure. Attached Figure Description

[0051] Figure 1 This is a diagram used to illustrate the waveform of the loss tangent (tanδ).

[0052] Figure 2 This is a schematic cross-sectional view showing one embodiment of the adhesive film.

[0053] Figure 3 This is a schematic cross-sectional view showing one embodiment of the connecting structure.

[0054] Figure 4 It means Figure 3 A schematic cross-sectional view of the manufacturing method of the connecting structure.

[0055] Figure 5 This is an example of a binarized image of a temporary press-fit object based on a differential interference microscope. Detailed Implementation

[0056] In this specification, the numerical range indicated by "~" represents the range encompassing the minimum and maximum values ​​recorded before and after "~". Within the numerical range described in stages in this specification, the upper or lower limit of the numerical range for a certain stage can be replaced by the upper or lower limit of the numerical range for other stages. Furthermore, within the numerical range described in this specification, the upper or lower limit of the numerical range can also be replaced by the values ​​shown in the examples. Moreover, the individually described upper and lower limits can be arbitrarily combined. In this specification, "(meth)acrylate" refers to at least one of acrylate and its corresponding methacrylate. The same applies to other similar expressions such as "(meth)acryloyl". "(poly)" refers to both the presence and absence of the prefix "poly". "A or B" can include either A or B, or both. Unless otherwise specified, the materials exemplified below can be used individually or in combination of two or more. In the case where there are multiple substances that are components in a composition, unless otherwise specified, the content of each component in the composition refers to the total amount of the multiple substances present in the composition.

[0057] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. However, the present disclosure is not limited to the following embodiments.

[0058] <Film adhesive>

[0059] The film adhesive of this embodiment comprises (A) a thermoplastic resin (hereinafter also referred to as "component (A)") and (B) a free radical polymerizable compound (hereinafter also referred to as "component (B)"). The waveform of the loss tangent (tanδ) obtained by dynamic viscoelasticity measurement after heating at 170°C for 5 seconds has multiple maxima. The film adhesive of this embodiment exhibits excellent temporary fixation and reprocessing workability, and can exert sufficient adhesive force. Furthermore, it is presumed that this effect is achieved for the following reason: it is presumed that the adhesive representing the above waveform is in a state where the polymer compatibility in the cured product is poor, thereby enabling the polymer of the free radical polymerizable compound, which easily yields adhesive force, to be concentrated into islands, ensuring sufficient adhesive force even considering a tight fit.

[0060] The above dynamic viscoelasticity determination can be performed through the following steps.

[0061] (i) Prepare a sample before heating by laminating a film adhesive to a thickness of approximately 100 μm. The thickness of each laminated film adhesive can be set to 5–50 μm.

[0062] (ii) The sample prepared in (i) was heat-cured using a hot press machine “FCB3” (manufactured by Panasonic Corporation, product name) under the conditions of a support temperature of 90°C, a set pressure of 100N, a reaching temperature of 170°C, and a heating time of 5 seconds to obtain a sample for testing.

[0063] (iii) The test specimen obtained in (ii) is placed in the dynamic viscoelasticity measuring device "RSA-G2" (manufactured by TA Instruments Co., Ltd., product name) and the dynamic viscoelasticity is measured under the following conditions: tensile mode, measuring frequency 0.1 Hz, strain 0.1%, heating rate 10 °C / min, and measuring temperature range 0 °C to 200 °C.

[0064] The waveform of the loss tangent (tanδ) refers to the relationship between temperature and the loss tangent (tanδ) obtained through the above measurements. Furthermore, in this disclosure, the terminology used for the waveform of the loss tangent (tanδ) is defined as follows. Additionally, Figure 1 This is a diagram used to illustrate the waveform of the loss tangent (tanδ).

[0065] tanδ peak: refers to the point where the increase or decrease of tanδ changes from increasing to decreasing. Figure 1 (PT1 and PT2 in the text), the increase refers to the continuous increase of tanδ at temperatures above 5℃.

[0066] The tanδ peak bottom refers to the point where the increase or decrease of tanδ changes from decreasing to increasing. Figure 1 In PB1), the decrease refers to the continuous decrease of tanδ above 5℃.

[0067] Temperature difference between tanδ peaks: refers to the temperature difference between the tanδ peak peak on the high-temperature side and the tanδ peak peak on the low-temperature side. Figure 1 (D1 in the middle).

[0068] The difference in tanδ between the tanδ peak base and the tanδ peak tip: refers to the difference in tanδ between the tanδ peak tip and the tanδ peak base where tanδ is smaller. Figure 1 (D2 in the middle).

[0069] From the viewpoint of compatibility, the waveform of the loss tangent (tanδ) of the film adhesive in this embodiment can have two maxima, i.e., it can exhibit bimodal characteristics. In this case, from the viewpoint of more precisely defining the peak shape, the tanδ difference (intensity difference) between the tanδ peak trough and the tanδ peak apex can be 0.02 or more. From the viewpoint of the bimodal waveform of tanδ, the temperature difference between the tanδ peak apexes can be within 50°C, or it can be 20°C or more and 50°C or less. Furthermore, the temperature of the tanδ peak apex on the low-temperature side can be 40°C or more and 70°C or less, and the temperature of the tanδ peak apex on the high-temperature side can be 70°C or more and 100°C or less.

[0070] From the viewpoint of storage stability, the waveform of the loss tangent (tanδ) of the film adhesive of this embodiment can have a maximum value between 40°C and 90°C. From the viewpoint of compatibility and storage stability, the waveform of the loss tangent (tanδ) can have two maximum values ​​between 40°C and 100°C. The temperature difference between the two maximum values ​​can be more than 20°C and less than 50°C.

[0071] In addition, as a method for making the waveform of loss tangent (tanδ) satisfy the above conditions (e.g., bimodality, temperature range of tanδ peaks, temperature difference between tanδ peaks, and tanδ difference between tanδ peak bottom and tanδ peak top), several of the following methods can be combined.

[0072] (i) Combine two or more (A) components and adjust their proportions.

[0073] (ii) Adjust the ratio of component (A) to component (B).

[0074] For example, in case (ii), the content of component (B) can be adjusted to 70 to 80 parts by mass relative to 100 parts by mass of component (A).

[0075] As an example of a combination, the content of component (B) can be adjusted to be more than 80 parts by mass relative to the content of component (A) of 100 parts by mass, and the ratio of components (A1) and (A2) described later [(A1) / (A2)] can be adjusted to be less than 1 / 2.

[0076] The film adhesive of this embodiment can be used, for example, as a component constituting the adhesive layer in the adhesive film (electrical connection adhesive film) used in the following method.

[0077] A method for manufacturing a connection structure includes: a step of laminating an adhesive film onto the surface of a first circuit component having a first electrode (e.g., a first circuit component having a first circuit electrode formed on the main surface of a first substrate) on which the first electrode is formed; and a step of disposing a second circuit component having a second electrode (e.g., a second circuit component having a second circuit electrode formed on the main surface of a second substrate) on the first circuit component on which the adhesive film is laminated, such that the first electrode and the second electrode are facing each other, and then thermally pressing them together, thereby electrically connecting the first electrode and the second electrode to each other.

[0078] [(A) Composition: Thermoplastic resin]

[0079] As component (A), one or more resins selected from polyimide resin, polyamide resin, phenoxy resin, poly(meth)acrylic resin, polyester resin, polyurethane resin, polyester-type polyurethane resin, and polyvinyl butyral resin can be included. From the viewpoint that multiple maxima can be easily obtained in the waveform of the loss tangent (tanδ), two or more of the above-mentioned thermoplastic resins can be included, as well as two or more thermoplastic resins with different Tg values. As combinations of resins, examples include combinations of phenoxy resin and poly(meth)acrylic resin, combinations of phenoxy resin and polyester resin, combinations of phenoxy resin and polyester-type polyurethane resin, and combinations of phenoxy resin and polyimide resin.

[0080] From the perspective of resins with higher Tg, polyester resins can be polyethylene naphthalate (PET) resins. PET resins can be obtained by transesterification and polycondensation of naphthalene dicarboxylic acid esters with diethylene glycol, or by direct polymerization of naphthalene dicarboxylic acid with diethylene glycol. Furthermore, phenoxy resins can be obtained by reacting difunctional phenols with epichlorohydrin to a high molecular weight, or by polyaddition reaction of difunctional epoxy resins with difunctional phenols.

[0081] The film-like adhesive of this embodiment may contain a rubber component as component (A). Examples of rubber components 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.

[0082] From the viewpoint of obtaining resin systems with different compatibility, the film adhesive of this embodiment may contain polyester-type polyurethane resin (hereinafter also referred to as "(A1) component") and phenoxy resin (hereinafter also referred to as "(A2) component") as thermoplastic resins.

[0083] From the perspective of increasing the tanδ (intensity) of the tanδ peak at low temperature and easily exhibiting bimodality, the mass ratio of (A2) component to (A1) component [(A2) / (A1)] can be greater than 2 and less than 2.5.

[0084] From a film-forming perspective, the weight-average molecular weight of thermoplastic resins can be above 5,000 or above 10,000. From an adhesive perspective, it can be below 80,000 or below 150,000. From both adhesive and film-forming perspectives, it can be between 5,000 and 150,000, or between 10,000 and 80,000. The weight-average molecular weight of thermoplastic resins refers to the weight-average molecular weight (converted from standard polystyrene) determined by GPC (gel permeation chromatography).

[0085] In addition, in this disclosure, a thermoplastic resin having free radical polymerizable functional groups is used as (B) a free radical polymerizable compound.

[0086] From the viewpoint of film formation, based on the resin composition of the film adhesive (e.g., components other than conductive particles and fillers), the content of component (A) in the film adhesive can be 20% or more by mass or 30% or more by mass, or 60% or less by mass or 50% or less by mass, or 20 to 60% by mass or 30 to 50% by mass.

[0087] Furthermore, the content of component (A) relative to the total mass of components (A) and (B) 100 parts by mass can be 30 or more, 40 or more, or 50 or more, or it can be less than 90, 70 or less, or less than 60, or it can be 50 to 60 parts by mass.

[0088] [(B) Component: Free radical polymerizable compound]

[0089] (B) Components may be compounds having free radical polymerizable functional groups. Examples of free radical polymerizable functional groups include vinyl, acryloyl, and methacrylate. Among these, compounds having acryloyl and / or methacrylate can be used. (B) Components may be used alone or in combination of two or more.

[0090] As component (B), the compound described below can be used in either the monomer or oligomer state, or both monomer and oligomer can be used simultaneously.

[0091] As component (B), it is a polyfunctional (meth)acrylate compound having two or more (meth)acryloyloxy groups. Examples of such (meth)acrylate compounds include epoxy (meth)acrylates, polyurethane (meth)acrylates, polyether (meth)acrylates, polyester (meth)acrylates, trimethylolpropane tri(meth)acrylates, polyethylene glycol di(meth)acrylates, etc., polyalkylene glycol di(meth)acrylates, dicyclopentenyl (meth)acrylates, dicyclopentenoxyethyl (meth)acrylates, neopentyl glycol di(meth)acrylates, dipentaerythritol hexa(meth)acrylates, isocyanuric acid modified difunctional (meth)acrylates, isocyanuric acid modified trifunctional (meth)acrylates, etc. Examples of epoxy (meth)acrylates include those obtained by adding (meth)acrylic acid to the two glycidyl groups of bisphenol fluorene diglycidyl ether, and compounds obtained by introducing (meth)acryloyloxy groups into compounds obtained by adding ethylene glycol and / or propylene glycol to the two glycidyl groups of bisphenol fluorene diglycidyl ether. These compounds can be used alone or in combination of two or more.

[0092] Among the aforementioned (meth)acrylate compounds, from the viewpoint of obtaining better adhesion through the presence of polyurethane bonds, (poly)urethane (meth)acrylate compounds can be used. From the viewpoint of obtaining better adhesion, based on the total mass of component (B), the content of the (poly)urethane (meth)acrylate compound can be 30–90% by mass, 40–80% by mass, or 50–70% by mass.

[0093] Furthermore, as component (B), from the viewpoint of improving heat resistance, it is possible to use a component having at least one part of the structure selected from the group consisting of a bicyclopentane skeleton, a tricyclodecane skeleton, and a triazine ring.

[0094] Furthermore, from the viewpoint of further improving heat resistance, component (B) may contain a (meth)acrylate compound having a tricyclic decane skeleton. Based on the total mass of component (B), the content of the (meth)acrylate compound having a tricyclic decane skeleton may be 2–20% by mass, 2–15% by mass, or 2–10% by mass.

[0095] From the viewpoint of achieving better adhesion, film adhesives can contain monofunctional (meth)acrylate compounds as component (B). Examples of monofunctional (meth)acrylate compounds include pentaerythritol (meth)acrylate, 2-cyanoethyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenoxyethyl (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 iso... Decyl (meth)acrylate, isooctyl (meth)acrylate, 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, and (meth)acryloylmorpholine (meth)acrylates containing glycidyl groups obtained by reacting one glycidyl group of an epoxy resin having multiple glycidyl groups with (meth)acrylic acid. These compounds can be used alone or in combination of two or more.

[0096] From the viewpoint of achieving better adhesion, film adhesives may contain compounds with free radical polymerizable functional groups such as allyl, maleimide, and vinyl groups as component (B). Examples of such compounds include N-vinylimidazolium, N-vinylpyridine, N-vinylpyrrolidone, N-vinylformamide, N-vinylcaprolactam, 4,4'-vinylbis(N,N-dimethylaniline), N-vinylacetamide, N,N-dimethylacrylamide, N-isopropylacrylamide, and N,N-diethylacrylamide.

[0097] For the purpose of improving adhesion, film adhesives may contain a free radical polymerizable compound with a phosphate ester structure as component (B). The free radical polymerizable compound with a phosphate ester structure may be, for example, a compound represented by the following formula (1), (2) or (3).

[0098]

[0099] In equation (1), R 1 R represents a hydrogen atom or a methyl group. 2 The symbol represents (meth)acryloyloxy, where a and b independently represent integers from 1 to 8. Multiple R groups within the same molecule... 1 R 2 a and b can be the same as each other or different.

[0100]

[0101] In equation (2), R 3 The symbol represents (meth)acryloyloxy, where c and d independently represent integers from 1 to 8. Multiple R groups within the same molecule... 3 c and d can be the same as each other or different.

[0102]

[0103] In equation (3), R 4 R represents a hydrogen atom or a methyl group. 5 The symbol represents (meth)acryloyloxy, where e and f independently represent integers from 1 to 8. Multiple R groups within the same molecule... 4 R 4 e and f can be the same as each other or different.

[0104] Examples of free radical polymerizable compounds with phosphate ester structures include (meth)acrylate phosphate ethyl ester, (meth)acrylate phosphate propyl ester, acid phosphate oxy polyethylene glycol mono(meth)acrylate, acid phosphate oxy propylene glycol mono(meth)acrylate, 2,2'-di(meth)acryloyloxy diethyl phosphate, EO (ethylene oxide) modified di(meth)acrylate, phosphate modified epoxy (meth)acrylate, and ethylene phosphate.

[0105] The content of component (B) in the film adhesive relative to the total mass of components (A) and (B) of 100 parts by mass can be more than 10 parts by mass, more than 30 parts by mass, or more than 40 parts by mass, or less than 70 parts by mass, less than 60 parts by mass, or less than 50 parts by mass, or 40 to 50 parts by mass.

[0106] From the perspective of making the waveform of loss tangent (tanδ) bimodal, the ratio of the content of component (B) to the content of component (A) [(B) / (A)] can be 0.7 to 0.8. When (B) / (A) exceeds 0.8, the mass ratio of component (A2) to component (A1) [(A2) / (A1)] can be set to 2 or more.

[0107] When the film adhesive contains a free radical polymerizable compound with a phosphate ester structure as component (B), the content of the free radical polymerizable compound with a phosphate ester structure may be more than 1 part by mass, or less than 100 parts by mass, less than 50 parts by mass, or less than 10 parts by mass relative to the total mass of components (a) and (b) of 100 parts by mass.

[0108] The film adhesive of this embodiment may further contain at least one of (C) a free radical polymerization initiator (hereinafter also referred to as "(C) component"), (D) a filler material (hereinafter also referred to as "(D) component"), (E) a silane coupling agent (hereinafter also referred to as "(E) component"), and (F) conductive particles (hereinafter also referred to as "(F) component").

[0109] [(C) Component: Free radical polymerization initiator]

[0110] As component (C), compounds such as peroxides and azo compounds can be selected arbitrarily. From the viewpoint of excellent stability, reactivity, and compatibility, peroxides with a 1-minute half-life temperature of 90°C to 175°C and a molecular weight of 180 to 1000 are preferred as component (C). "1-minute half-life temperature" refers to the temperature at which the half-life of the peroxide is 1 minute. "Half-life" refers to the time it takes for the concentration of a compound to decrease to half its initial value at a specified temperature.

[0111] Free radical polymerization initiators can be selected from, for example, 1,1,3,3-tetramethylbutyl peroxyneodecanate, di(4-tert-butylcyclohexyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, cumeneyl peroxyneodecanate, 1,1,3,3-tetramethylbutyl peroxyneodecanate, dilauroyl peroxide, 1-cyclohexyl-1-methylethyl peroxyneodecanate, tert-hexyl peroxyneodecanate, tert-butyl peroxyneodecanate, tert-butyl peroxynepentanoate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 2,5- Dimethyl-2,5-di(2-ethylhexanoylperoxide)hexane, tert-hexylperoxide-2-ethylhexanoate, tert-butylperoxide-2-ethylhexanoate, tert-butylperoxide neoheptanoate, tert-pentylperoxide-2-ethylhexanoate, di-tert-butylperoxide hexahydrophthalic acid ester, tert-pentylperoxide-3,5,5-trimethylhexanoate, 3-hydroxy-1,1-dimethylbutylperoxide neodecanoate, 1,1,3,3-tetramethylbutylperoxide-2-ethylhexanoate, tert-pentylperoxide neodecanoate, tert-pentylperoxide-2-ethylhexanoate, 3-methylbenzyl Acyl peroxide, 4-methylbenzoyl peroxide, di(3-methylbenzoyl) peroxide, dibenzoyl peroxide, di(4-methylbenzoyl) peroxide, 2,2'-azobis-2,4-dimethylpentanonitrile, 1,1'-azobis(1-acetoxy-1-phenylethane), 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), dimethyl-2,2'-azobisisobutyronitrile, 4,4'-azobis(4-cyanopentanoic acid), 1,1'-azobis(1-cyclohexanecarboxylonitrile), tert-hexyl peroxide isopropyl monocarbon One or more compounds selected from the following: ester, tert-butyl peroxymaleic acid, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxylaurate, 2,5-dimethyl-2,5-di(3-methylbenzoyl peroxy)hexane, tert-butyl peroxy-2-ethylhexyl monocarbonate, tert-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoyl peroxy)hexane, tert-butyl peroxybenzoate, dibutyl peroxytrimethyl adipate, tert-pentyl peroxyoctanoate, tert-pentyl peroxyisononanoate, and tert-pentyl peroxybenzoate.

[0112] The content of component (C) in the film adhesive can be more than 1 part or more than 2.5 parts by mass relative to the total mass of components (A) and (B) 100 parts by mass, or less than 15 parts by mass, less than 10 parts by mass, or less than 5 parts by mass.

[0113] [(D) Component: Filler Material]

[0114] The filler material can be particles composed of silicon, calcium, zirconium, titanium, aluminum, carbon, bismuth, cobalt, copper, iron, indium, manganese, tin, yttrium, zinc, or compounds or organic compounds containing these elements. The average particle size is, for example, 0.005 μm to 25 μm.

[0115] The content of component (D) in the film adhesive can be more than 1 part or more than 5 parts by mass relative to the total mass of components (A) and (B) 100 parts by mass, or it can be less than 30 parts by mass, less than 25 parts by mass, or less than 20 parts by mass.

[0116] [(E) Component: Silane coupling agent]

[0117] Examples of silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldiethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-ureopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, and their condensates.

[0118] The content of component (E) in the film adhesive may be more than 0.1 parts by mass, more than 0.2 parts by mass, or more than 0.25 parts by mass, or less than 10 parts by mass or less than 5 parts by mass, relative to the total mass of components (A) and (B) 100 parts by mass.

[0119] [(F) Component: Conductive particles]

[0120] As component (F), examples include metallic particles such as Au, Ag, Ni, Cu, and solder, and conductive particles such as conductive carbon particles. The conductive particles can be conductive particles having a core formed of non-conductive glass, ceramic, or plastic particles and a layer of the aforementioned metal covering the core, or conductive particles such as metallic particles or conductive carbon particles. Especially when the amount of conductive particles increases, from the viewpoint of preventing short circuits between conductive particles and improving the insulation between adjacent circuit electrodes, the conductive particles can be insulating conductive particles having the aforementioned conductive particles and an insulating covering layer formed of an insulating material such as a polymer resin covering the surface of the conductive particles. These conductive particles, conductive covering particles, and insulating conductive covering particles can be used individually or in combination of two or more types.

[0121] From the viewpoint of excellent dispersibility and conductivity, the average particle size of the conductive particles can be 1 μm to 50 μm. Based on the total amount of the film-forming adhesive, the content of conductive particles can be 0.1% by volume or more, 30% by volume or less, or 10% by volume or less. The content of 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, for example, by converting weight to volume using specific gravity. Furthermore, for example, the component can be added to a graduated cylinder or similar container containing a suitable solvent (water, alcohol, etc.) that does not dissolve or swell the component but sufficiently wets it, and the resulting increase in volume can be used as the calculated volume.

[0122] The film-like adhesive of this embodiment may contain other resins such as phenolic resin and melamine resin, softeners, curing accelerators, anti-aging agents, colorants, flame retardants, thixotropic agents, adhesion promoters, thickeners, leveling agents, weather resistance promoters, polymerization inhibitors, and other additives. Examples of polymerization inhibitors include hydroquinone and hydroquinone methyl ethers.

[0123] The film-like adhesive of this embodiment can be manufactured by the following method. Specifically, firstly, 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). Then, the varnish composition is applied to a substrate that has undergone a demolding treatment using a doctor blade coater, roller coater, applicator, comma coater, mold coater, etc., and the solvent is evaporated by heating, thus forming a film-like adhesive on the substrate.

[0124] As a solvent for preparing the varnish composition, a solvent with the property of uniformly dissolving or dispersing the components can be used. 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 mixing and kneading of the varnish composition can be performed using, for example, a mixer, sand mill, three-roll mill, ball mill, bead mill, or homogenizing disperser.

[0125] As for the substrate, there are no particular restrictions as long as it is a heat-resistant material that can withstand the heating conditions that cause the solvent to evaporate. For example, substrates (e.g., films) formed from extended polypropylene (OPP), polyethylene terephthalate (PET), polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyolefins, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, polyimide, cellulose, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, synthetic rubber systems, liquid crystal polymers, etc., can be used.

[0126] The heating conditions for evaporating the solvent from the varnish composition coated on the substrate can be set to conditions that allow the solvent to evaporate sufficiently. For example, the heating conditions can be 40°C or higher and 120°C or lower, and for 0.1 minutes or higher and 10 minutes or lower.

[0127] In the film adhesive of this embodiment, a portion of the solvent may remain without being removed. For example, based on the total mass of the film adhesive, the solvent content in the film adhesive of this embodiment may be 10% by mass or less, or 5% by mass or less.

[0128] From the viewpoint of temporary fixation, the film adhesive of this embodiment can achieve an adhesion rate of 45-60% as measured by the following method.

[0129] 1. A film-like adhesive, cut to a width of 1.2 mm, is applied to a SiN film with a thickness of 0.7 mm. x The substrate (having a glass substrate and a 0.2 μm thick silicon nitride (SiN) layer formed on the glass substrate) x On the thin layer of the adhesive, three silicon films (200 μm thick) are covered.

[0130] 2. Following step 1, a temporary press-fit body is obtained by temporarily pressing a film-like adhesive onto the glass under conditions of 70°C, 1 MPa, and 1 second.

[0131] 3. Use a differential interference microscope “ECLIPSE L300” (manufactured by Nikon Corporation) to photograph the temporary press-fit from the glass side.

[0132] 4. The captured images were cropped and binarized using a self-made program (programming language: Python, OpenCV (manufactured by Intel Corporation, module name) for image processing). The cropping was performed so that only the area where the adhesive film remained in contact with the glass (the substrate) was visible. The binarization was performed so that the areas where the glass and adhesive adhered tightly became black areas.

[0133] 5. Based on the binarized image, calculate the area ratio of the black portion using the following formula, and use it as the density ratio.

[0134] The area ratio of the black portion (%) = [(number of pixels in the black portion) × 100] / (total number of pixels in the image)

[0135] If the adhesion rate is above 45%, the adhesive is not easy to fall off during temporary fixing. If the adhesion rate is below 60%, if the position of the adhesive shifts during temporary fixing, it is easy to peel off the adhesive and then temporarily fix a new adhesive.

[0136] <Adhesive film>

[0137] The adhesive film of this embodiment has the film-like adhesive described above.

[0138] Figure 2 This is a schematic cross-sectional view illustrating an adhesive film according to one embodiment. For example... Figure 2 As shown, in one embodiment, the adhesive film 1 is composed of a single layer, which is formed by adhesive component 2 and conductive particles 3 dispersed in adhesive component 2. In one embodiment, adhesive component 2 contains components (A) and (B) as described above, as well as other components such as components (C) to (E).

[0139] The adhesive film 1 can be in an uncured state or in a partially cured state.

[0140] The thickness of the adhesive film 1 can be, for example, 3 μm or more or 10 μm or less, or 30 μm or less or 20 μm or less.

[0141] In one embodiment, the adhesive film of this embodiment may be a multilayer structure having a first adhesive layer formed of a film-like adhesive and a second adhesive layer formed 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 the film-like adhesive of this embodiment described above.

[0142] The adhesive film mentioned above can be an anisotropic conductive adhesive film (anisotropic conductive film) or a conductive adhesive film that does not have anisotropic conductivity.

[0143] <Connection Structure>

[0144] Another embodiment of this disclosure is a connection structure comprising: a first circuit component having a first electrode; a second circuit component having a second electrode; and a connection portion disposed between the first circuit component and the second circuit component, and electrically connecting the first electrode and the second electrode to each other, the connection portion comprising a cured product of the aforementioned film adhesive.

[0145] Figure 3 This is a schematic cross-sectional view illustrating one embodiment of the connecting structure. For example... Figure 3 As shown, the connecting structure 10 includes: a first circuit component 4 and a second circuit component 5 facing each other; and a connecting portion 6 that connects the first circuit component 4 and the second circuit component 5 between the first circuit component 4 and the second circuit component 5.

[0146] The first circuit component 4 includes a first circuit substrate 41 and a first electrode 42 formed on the main surface 41a of the first circuit substrate 41. The second circuit component 5 includes a second circuit substrate 51 and a second electrode 52 formed on the main surface 51a of the second circuit substrate 51.

[0147] There are no particular restrictions on whether the first circuit component 4 and the second circuit component 5 are components that have electrodes that require electrical connection. As components with electrodes (circuit components, etc.), inorganic substrates such as semiconductors, glass, and ceramics can be used; polyimide substrates such as TCP, FPC, and COF can be used; substrates with electrodes formed on films such as polycarbonate, polyester, and polyethersulfone can be used; printed circuit boards, etc., and multiple of these can be used in combination.

[0148] The connecting portion 6 includes a cured film of adhesive, and contains an insulating material 7 and conductive particles 3 as components of the adhesive. The conductive particles 3 can be disposed not only between the opposing first electrode 42 and second electrode 52, but also between the main surface 41a of the first circuit board 41 and the main surface 51a of the second circuit board 51. In the connecting structure 10, the first electrode 42 and the second electrode 52 are electrically connected by the conductive particles 3. That is, the conductive particles 3 are in contact with both the first electrode 42 and the second electrode 52.

[0149] In the connecting structure 10, the opposing first electrode 42 and second electrode 52 are electrically connected by conductive particles 3, but if the film adhesive does not contain conductive particles, the first electrode 42 and second electrode 52 can be in direct contact.

[0150] <Manufacturing Method of Connecting Structures>

[0151] Another embodiment of this disclosure is a method for manufacturing a connecting structure, which includes: a step of laminating the adhesive film of this embodiment described above on the surface of a first circuit component having a first electrode on which the first electrode is formed; and a step of disposing a second circuit component having a second electrode on the first circuit component on which the adhesive film is laminated, so that the first electrode and the second electrode are facing each other, and then heat-pressing them together to electrically connect the first electrode and the second electrode to each other.

[0152] Figure 4 This is a schematic cross-sectional view illustrating one embodiment of a manufacturing method for a connecting structure. For example... Figure 4As shown in (a), firstly, a first circuit component 4 and an adhesive film 1 are prepared. Next, the adhesive film 1 is laminated onto the main surface 41a of the first circuit component 4. When the adhesive film 1 is laminated onto a substrate (not shown), the laminate is pressed onto the first circuit component 4 such that the adhesive film 1 side of the substrate faces the first circuit component 4. When the adhesive film 1 has a multilayer structure comprising a first adhesive layer formed of a film-like adhesive and a second adhesive layer formed of an adhesive composition containing conductive particles, it is preferable to laminate in such a way that the first adhesive layer side contacts the main surface 41a of the first circuit component 4.

[0153] In this embodiment, it is possible to Figure 4 (a) Apply pressure in the directions of arrows A and B to temporarily fix the adhesive film 1 to the first circuit component 4 (see reference). Figure 4 (b)). At this point, pressure can be applied while heating is being carried out.

[0154] Next, as Figure 4 As shown in (c), the second circuit component 5 is further disposed on the adhesive film 1 temporarily fixed to the first circuit component 4, such that the second electrode 52 side faces the first circuit component 4 (i.e., the adhesive film 1 is disposed between the first circuit component 4 and the second circuit component 5, with the first electrode 42 and the second electrode 52 facing each other). When the adhesive film 1 is laminated on a substrate (not shown), the second circuit component 5 is disposed on the adhesive film 1 after the substrate is peeled off.

[0155] Then, they will be in Figure 4 (c) Heat-pressing is performed in the directions of arrows A and B. This cures the adhesive film 1, resulting in a formal connection that electrically connects the first electrode 42 and the second electrode 52 to each other. As a result, the following can be obtained: Figure 3 The connection structure 10 shown.

[0156] According to the manufacturing method of the connecting structure of this embodiment, since the film-like adhesive has excellent temporary fixation properties and can exert sufficient adhesive force, the connecting structure can be manufactured effectively. Furthermore, even in the event of reprocessing work such as re-temporary fixation, the adhesive can be peeled off with good workability.

[0157] Example

[0158] The present invention will be described in more detail below through embodiments, but the present invention is not limited to the embodiments.

[0159] <Synthesis of polyester-type polyurethane resin (A1)>

[0160] 48 parts by mass of isophthalic acid and 37 parts by mass of neopentyl glycol were added to a stainless steel autoclave equipped with a stirrer, thermometer, condenser, vacuum generator, and nitrogen inlet pipe, and further 0.02 parts by mass of tetrabutoxytitanate as a catalyst were added. The mixture was then heated to 220°C under a nitrogen atmosphere and stirred for 8 hours. The pressure was then reduced to atmospheric pressure (760 mmHg) and cooled to room temperature. A white precipitate was formed. The precipitate was then removed, washed with water, and vacuum dried to obtain a polyester polyol. After thorough drying, the polyester polyol was dissolved in MEK (methyl ethyl ketone) and transferred to a four-necked flask equipped with a stirrer, dropping funnel, reflux cooler, and nitrogen inlet pipe. Furthermore, dibutyltin dilaurate was added as a catalyst in an amount equal to 0.05 parts by mass relative to 100 parts by mass of the polyester polyol, and 4,4'-diphenylmethane diisocyanate in an amount equal to 50 parts by mass relative to 100 parts by mass of the polyester polyol was dissolved in MEK and added using a dropping funnel. The mixture was stirred at 80°C for 4 hours, thereby obtaining the target polyester-type polyurethane resin. The weight-average molecular weight of the polyester-type polyurethane resin was 15,000. The weight-average molecular weight was determined by gel permeation chromatography (GPC) under the following conditions using a calibration curve based on standard polystyrene.

[0161] (Measurement conditions)

[0162] Device: TOSOH CORPORATION GPC-8020

[0163] Detector: Manufactured by TOSOH CORPORATION RI-8020

[0164] Column: Gelpack GLA160S+GLA150SG 2000Hhr manufactured by Resonac Holdings Corporation

[0165] Solvent: Tetrahydrofuran

[0166] Injection volume: 60μL

[0167] Pressure: 2.94 × 10 6 Pa

[0168] Flow rate: 1.00 mL / min

[0169] <Synthesis of Polyurethane Acrylate B1>

[0170] In a 2L four-necked flask equipped with a thermometer, stirrer, inert gas inlet, and reflux cooler, 4000 parts by mass of polycarbonate diol (manufactured by Aldrich, number average molecular weight 2000), 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 were added to prepare a reaction solution. The reaction solution was heated to 70°C, and 666 parts by mass of isophorone diisocyanate (IPDI) were added dropwise over 3 hours to allow the reaction to proceed. After the addition was complete, the reaction was continued for 15 hours. The reaction was considered complete when the NCO% (NCO content) fell below 0.2% by mass, yielding polyurethane acrylate. The NCO% was confirmed using an automatic potentiometric titration device (product name: AT-510, manufactured by KYOTOELECTRONICS MANUFACTURING CO., LTD.). Based on the results of GPC analysis, the weight-average molecular weight of the polyurethane acrylate was 8500 (converted from standard polystyrene). Furthermore, the weight-average molecular weight was determined by gel permeation chromatography (GPC) under the following conditions using a calibration curve based on standard polystyrene.

[0171] (Measurement conditions)

[0172] Device: TOSOH CORPORATION GPC-8020

[0173] Detector: Manufactured by TOSOH CORPORATION RI-8020

[0174] Chromatographic column: Gelpack GLA160S+GLA150S manufactured by Resonac Holdings Corporation

[0175] Sample concentration: 120 mg / 3 mL

[0176] Solvent: Tetrahydrofuran

[0177] Injection volume: 60μL

[0178] Pressure: 2.94 × 10 6 Pa (30kgf / cm) 2 )

[0179] Flow rate: 1.00 mL / min

[0180] [Preparation of film-like adhesives]

[0181] (Examples 1-3, Comparative Examples 1-4)

[0182] Varnish compositions were prepared by mixing the following ingredients in the proportions (parts by mass) shown in Table 1.

[0183] (Thermoplastic resin)

[0184] A1: The polyester-type polyurethane resin synthesized as described above (A1).

[0185] A2: A 40% by mass solution prepared by dissolving 40g of bisphenol A phenoxy resin (product name: PKHC, manufactured by Union Carbide Corporation) in 60g of methyl ethyl ketone (the amount in the table represents the amount of bisphenol A phenoxy resin).

[0186] (Free radical polymerizable compounds)

[0187] B1: Polyurethane acrylate (UA1) synthesized as described above.

[0188] B2: Isocyanuric acid EO-modified diacrylate (Product name: M-215, manufactured by TOAGOSEI CO., LTD.)

[0189] B3: Diacrylates with a tricyclic decane backbone (dicyclopentadiene type diacrylates) (Product name: DCP-A, manufactured by KYOEISHA CHEMICAL CO.,LTD.)

[0190] B4: Pentaerythritol tetra(3-mercaptobutyrate) (Product name: Karenz MT PE-1 (“Karenz MT” is a registered trademark), manufactured by Resonac Holdings Corporation)

[0191] B5: 2-Methacryloxyethyl acid phosphate (Product name: LIGHT ESTER P-2M, manufactured by KYOEISHACHEMICAL Co.,LTD.)

[0192] (Free radical polymerization initiator)

[0193] C1: Benzoyl peroxide (Product name: NYPER BMT-K40, manufactured by NOF CORPORATION)

[0194] C2: Lauroyl peroxide (Product name: PEROYL L, manufactured by NOF CORPORATION)

[0195] (Filling material)

[0196] D1: Silica microparticles (Product name: R104, manufactured by NIPPON AEROSIL CO., LTD., average particle size (primary particle size): 12nm)

[0197] (Coupled agent)

[0198] E1: 3-Methacryloxypropyltrimethoxysilane (Product name: KBM503, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0199] The varnish composition obtained above was applied onto a PET film with a thickness of 50 μm using a coating apparatus. Then, it was dried with hot air at 70°C for 3 minutes, forming a film-like adhesive with a thickness (after drying) of 8.5 μm on the PET film.

[0200] [Evaluation of film-type adhesives]

[0201] Regarding the film adhesives prepared in the examples and comparative examples, the waveform of the loss tangent (tanδ), the determination and evaluation of the adhesion, and the determination of the adhesive force were performed according to the methods shown below.

[0202] <Evaluation of the waveform of loss tangent (tanδ)>

[0203] First, regarding the film adhesive, the waveform of the loss tangent (tanδ) was obtained by performing dynamic viscoelasticity measurements according to the following steps.

[0204] (i) The film adhesive is laminated to a thickness of about 100 μm to prepare a sample before heating.

[0205] (ii) The sample prepared in (i) was heat-cured using a hot press machine “FCB3” (manufactured by Panasonic Corporation, product name) under the conditions of a support temperature of 90°C, a set pressure of 100N, a reaching temperature of 170°C, and a heating time of 5 seconds to obtain a sample for testing.

[0206] (iii) The test specimen obtained in (ii) is placed in the dynamic viscoelasticity measuring device "RSA-G2" (manufactured by TA Instruments Co., Ltd., product name) and the dynamic viscoelasticity is measured under the following conditions: tensile mode, measuring frequency 0.1 Hz, strain 0.1%, heating rate 10 °C / min, and measuring temperature range 0 °C to 200 °C.

[0207] Next, regarding the waveform of the loss tangent (tanδ) obtained in the above dynamic viscoelasticity measurement, the number of tanδ peaks and the presence or absence of tanδ peak troughs were confirmed, and the temperature difference between tanδ peaks and the tanδ difference between tanδ peak troughs and tanδ peaks were calculated based on these.

[0208] <Determination of Fit>

[0209] Regarding film adhesives, the adhesion ratio was determined by following these steps.

[0210] 1. A film-like adhesive, cut to a width of 1.2 mm, is applied to a SiN film with a thickness of 0.7 mm. x The substrate (having a glass substrate and a 0.2 μm thick silicon nitride (SiN) layer formed on the glass substrate) x On the thin layer of the adhesive, three silicon films (200 μm thick) are covered.

[0211] 2. Following step 1, a temporary press-fit body is obtained by temporarily pressing a film-like adhesive onto the glass under conditions of 70°C, 1 MPa, and 1 second.

[0212] 3. Use a differential interference microscope “ECLIPSE L300” (manufactured by Nikon Corporation) to photograph the temporary press-fit from the glass side.

[0213] 4. The captured images were cropped and binarized using a self-made program (programming language: Python, OpenCV (manufactured by Intel Corporation, module name) for image processing). The cropping was performed so that only the area where the adhesive film remained in contact with the glass (the substrate) was visible. The binarization was performed so that the areas where the glass and adhesive adhered tightly became black areas. Figure 5 This is an example of a binarized image of a temporary press-fit object based on a differential interference microscope.

[0214] 5. Based on the binarized image, calculate the area ratio of the black portion using the following formula, and use it as the density ratio.

[0215] The area ratio of the black portion (%) = [(number of pixels in the black portion) × 100] / (total number of pixels in the image)

[0216] <Evaluation of Fit>

[0217] As long as the fit rate measured above is within the range of 45% to 60%, good temporary fixation and reprocessability can be obtained. If the fit rate is less than 45%, temporary fixation is difficult. If the fit rate exceeds 60%, reprocessability deteriorates.

[0218] <Determination of Adhesion Force>

[0219] For film adhesives, the adhesive strength was determined according to the following method.

[0220] Using the prepared film adhesive, a circuit connection structure (connection structure) was fabricated by heating and pressing a 25 μm pitch COF (manufactured by FLEXSEED) and a glass substrate with thin-film electrodes (height: 1200 Å) formed of silicon nitride (SiNx) on the glass substrate (manufactured by GEOMATEC Co., Ltd.) at 180°C and 4.5 MPa for 4 seconds, with a width of 1 mm. The adhesion force of the obtained circuit connection structure at room temperature immediately after connection was measured using a Tensilon UTM-4 (manufactured by ToyoBaldwin Co., Ltd., peel strength 50 mm / min).

[0221] [Table 1]

[0222]

[0223] Symbol Explanation

[0224] 1-Adhesive film, 2-Adhesive component, 3-Conductive particle, 4-First circuit component, 5-Second circuit component, 6-Connector, 7-Insulating material, 10-Connecting structure, 41-First circuit board, 42-First electrode, 51-Second circuit board, 52-Second electrode.

Claims

1. A method for manufacturing a connecting structure, comprising: The process of laminating an adhesive film onto the surface of a first circuit component having a first electrode on which the first electrode is formed; and The process of placing a second circuit component having a second electrode on a first circuit component laminated with the adhesive film, such that the first electrode and the second electrode are facing each other, and then heat-pressing them together to electrically connect the first electrode and the second electrode to each other. The adhesive film has a film-like adhesive containing thermoplastic resin and free radical polymerizable compounds. The waveform of the loss tangent (tanδ) obtained by dynamic viscoelasticity measurement after heating the film adhesive at 170°C for 5 seconds has multiple maxima.

2. The method for manufacturing the connecting structure according to claim 1, wherein, The waveform of the loss tangent (tanδ) has a maximum value between 40℃ and 90℃.

3. The method for manufacturing the connecting structure according to claim 1 or 2, wherein, The waveform of the loss tangent (tanδ) has two maxima between 40℃ and 100℃, indicating that the temperature difference between the two maxima is above 20℃ and below 50℃.

4. The method for manufacturing the connecting structure according to claim 1 or 2, wherein, The thermoplastic resin contains polyester polyurethane resin and phenoxy resin.

5. The method for manufacturing the connecting structure according to claim 1 or 2, wherein, The free radical polymerizable compound contains (poly)urethane (meth)acrylate compounds.

6. A film-like adhesive comprising a thermoplastic resin and a free radical polymerizable compound, wherein, The waveform of the loss tangent (tanδ) obtained by dynamic viscoelasticity measurement after heating at 170°C for 5 seconds has multiple maxima.

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

8. The film adhesive according to claim 6, wherein, The waveform of the loss tangent (tanδ) has two maxima between 40℃ and 100℃, indicating that the temperature difference between the two maxima is above 20℃ and below 50℃.

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

10. The film adhesive according to claim 6, wherein, The free radical polymerizable compound contains (poly)urethane (meth)acrylate compounds.

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: The first adhesive layer is formed of the film-like adhesive; and The second adhesive layer is formed of an adhesive composition containing conductive particles.

14. A connecting structure comprising: The first circuit component has a first electrode; The second circuit component has a second electrode; and A connecting portion is disposed between the first circuit component and the second circuit component, and electrically connects the first electrode and the second electrode to each other. The connecting portion comprises a cured product of the film adhesive as described in claim 12.

Images