Connecting structures, circuit connection components and adhesive compositions

Abstract

This invention provides a connecting structure, a circuit connection member, and an adhesive composition. A connecting structure comprises: a first circuit member having a first circuit electrode; a second circuit member having a second circuit electrode; and a circuit connection member disposed between the first and second circuit members and electrically connecting the first and second circuit electrodes, wherein the linear thermal expansion L(t) of the circuit connection member at temperature t satisfies the condition dL(t) / dt < 0 at at least any one of t = 30°C to 12°C.

Description

[0001] This invention is a divisional application of the invention application with application number 2017800627096, application date September 21, 2017, and invention title "Connecting Structure, Circuit Connection Component and Adhesive Composition". Technical Field

[0002] This invention relates to connection structures, circuit connection components, and adhesive compositions. Background Technology

[0003] Traditionally, various adhesives have been used in semiconductor and display components to bond different circuit components together. Besides adhesion, adhesives require a range of properties including heat resistance and reliability under high temperature and humidity conditions. Furthermore, because circuit components utilize various organic substrates such as printed circuit boards and polyimide, or metals such as titanium, copper, and aluminum, as well as materials with diverse surface states like ITO, IZO, IGZO, SiN, and SiO2, the materials used in adhesives require molecular design tailored to the specific circuit components.

[0004] Recently, due to the simplification and lowering of manufacturing processes for semiconductor and display components, the use of amorphous ITO films and organic insulating films in circuit components has gradually increased. From a physical point of view, such as fewer surface irregularities, or a chemical point of view, such as low surface wettability, these films are often unfavorable for adhesion.

[0005] On the other hand, in order to ensure a strong bond between the circuit connection components obtained by curing the adhesive and the circuit components, additives such as coupling agents are sometimes added to the adhesive. These coupling agents generate interactions between the surfaces of the circuit connection components and the circuit components, such as covalent bonds, hydrogen bonds, and hydrophobic interactions caused by van der Waals forces. As coupling agents, silane coupling agents, coupling agents having phosphate groups, carboxyl groups, etc., can be used. For example, when the resin constituting the circuit connection component contains organic functional groups such as epoxy groups, acryloyl groups, and vinyl groups, and a coupling agent having an alkoxysilane structure, phosphate groups, etc., that generates interactions between the surface of the circuit component and the circuit connection component is used, the circuit component and the circuit connection component can be bonded more firmly (see Patent Documents 1-3).

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2003-282637

[0009] Patent Document 2: Japanese Patent Application Publication No. 2003-277694

[0010] Patent Document 3: Japanese Patent Application Publication No. 2013-191625 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] However, according to the research of the inventors, when using the additives described above, there is a problem: in high temperature and high humidity environments, depending on the type of circuit component, the interaction between the circuit connection component and the circuit component cannot function effectively, and the circuit connection component will peel off from the circuit component.

[0013] Therefore, the object of the present invention is to provide a connection structure that can suppress the stripping of circuit connection components from circuit components even in high temperature and high humidity environments, and a circuit connection component and adhesive composition used in the connection structure.

[0014] Methods for solving problems

[0015] In one embodiment, the present invention provides a connection structure comprising: a first circuit member having a first circuit electrode; a second circuit member having a second circuit electrode; and a circuit connection member disposed between the first circuit member and the second circuit member and electrically connecting the first circuit electrode and the second circuit electrode to each other, wherein the linear thermal expansion L(t) of the circuit connection member at temperature t satisfies the condition dL(t) / dt < 0 at at least any temperature t between t = 30°C and 120°C.

[0016] In another aspect, the present invention provides a circuit connection component whose linear thermal expansion L(t) at temperature t satisfies the condition dL(t) / dt < 0 at at least any temperature t between t = 30°C and 120°C.

[0017] The average linear thermal expansion coefficient of the above-mentioned circuit connection components at 30℃ to 120℃ is preferably less than or equal to 500ppm / ℃.

[0018] In another aspect, the present invention provides an adhesive composition in which the cured product of the adhesive composition has a linear thermal expansion l(t) at temperature t that satisfies the condition dl(t) / dt < 0 at at least any temperature t between t = 30°C and 120°C.

[0019] The average linear thermal expansion coefficient of the above-mentioned cured material at 30℃ to 120℃ is preferably less than or equal to 500ppm / ℃.

[0020] Invention Effects

[0021] According to the present invention, a connection structure capable of suppressing the stripping of circuit connection components from circuit components even under high temperature and high humidity conditions, and a combination of circuit connection components and adhesives used in the connection structure, are provided. Attached Figure Description

[0022] Figure 1 This is a schematic cross-sectional view showing one implementation of the connecting structure.

[0023] Figure 2 This is an example of a graph showing the relationship between temperature and linear thermal expansion. Detailed Implementation

[0024] The embodiments of the present invention will now be described in detail. However, the present invention is not limited to the embodiments described below. "(Meth)acrylic acid" refers to acrylic acid or methacrylic acid, and the same applies to other similar expressions such as (meth)acrylates.

[0025] Figure 1 This is a schematic cross-sectional view illustrating one implementation of the connecting structure. For example... Figure 1 As shown, the connecting structure 1 includes: a first circuit component 2, a second circuit component 3, and a circuit connection component 4 disposed between the first circuit component 2 and the second circuit component 3.

[0026] The first circuit component 2 includes a first substrate 5 and a first circuit electrode 6 disposed on the main surface of the first substrate 5. The second circuit component 3 includes a second substrate 7 and a second circuit electrode 8 disposed on the main surface of the second substrate 7.

[0027] The first circuit component 2 and the second circuit component 3 may be the same as or different from each other, and may be chip components such as semiconductor chips, resistive chips, and capacitor chips, or substrates such as printed circuit boards. The first substrate 5 and the second substrate 7 may be formed of inorganic materials such as semiconductors, glass, and ceramics, organic materials such as polyimide and polycarbonate, or composites such as glass / epoxy. The first circuit electrode 6 and the second circuit electrode 8 may be formed of gold, silver, tin, ruthenium, rhodium, palladium, osmium, indium, platinum, or crystalline or amorphous indium tin oxide (ITO).

[0028] Multiple circuit electrodes 6 and 8 (or an odd number, depending on the situation) are typically provided on the substrates 5 and 7 of these circuit components 2 and 3. The first circuit component 2 and the second circuit component 3 are arranged such that at least one pair of first circuit electrodes 6 and second circuit electrodes 8 are opposite to each other.

[0029] The circuit connection member 4 contains a cured adhesive component 9 and conductive particles 10 dispersed in the cured adhesive component 9. The conductive particles 10 in the circuit connection member 4 are positioned between the first circuit electrode 6 and the second circuit electrode 8, which are opposite to each other, thereby electrically connecting the first circuit electrode 6 and the second circuit electrode 8.

[0030] The circuit connection member 4 is a circuit connection member such that, from the viewpoint of preventing the circuit connection member 4 from being separated from the circuit members 2 and 3 and the circuit electrodes 6 and 8, the linear thermal expansion L(t)μm of the circuit connection member 4 at temperature t℃ satisfies the condition that dL(t) / dt<0 at at least any temperature t between t=30℃~120℃.

[0031] The linear thermal expansion L(t) of circuit connection component 4 was determined as follows: using a thermomechanical analysis apparatus, with a sample length of 10 mm, a width of 4 mm, a thickness of 0.1 mm, and a load of 5 gf (per 0.4 mm). 2 Under the conditions of cross-sectional area and heating rate of 5℃ / min, in the temperature range of t=0℃~200℃, with the linear thermal expansion at t=0℃ set as L(0)=0μm, the linear thermal expansion at temperature t℃ was measured every 0.1℃. Here, the linear thermal expansion refers to the linear thermal expansion in the length direction of the sample.

[0032] From the viewpoint of suppressing the stripping of the circuit connection member 4 from the circuit members 2 and 3 and the circuit electrodes 6 and 8, the linear thermal expansion L(t) of the circuit connection member 4 satisfies the condition that dL(t) / dt < 0 at at least any temperature t between t = 30°C and 120°C, preferably dL(t) / dt ≤ -0.01, more preferably dL(t) / dt ≤ -0.1, and even more preferably dL(t) / dt ≤ -0.5.

[0033] From the viewpoint of suppressing the separation of the circuit connection member 4 from the circuit members 2 and 3 and the circuit electrodes 6 and 8, the linear thermal expansion L(t) of the circuit connection member 4 satisfies the above-mentioned condition dL(t) / dt at at least any temperature t, preferably t = 30℃ to 100℃, more preferably t = 30℃ to 90℃, and even more preferably t = 30℃ to 80℃.

[0034] From the viewpoint of preventing the circuit connection member 4 from being separated from the circuit members 2 and 3 and the circuit electrodes 6 and 8, the average linear thermal expansion coefficient of the circuit connection member 4 at 30°C to 120°C is preferably less than or equal to 500 ppm / °C, more preferably less than or equal to 250 ppm / °C, and even more preferably less than or equal to 150 ppm / °C.

[0035] The coefficient of linear thermal expansion (ppm / ℃) of the circuit connection component 4 is defined as the amount of linear thermal expansion (μm) of 1 m length of the circuit connection component 4 for every 1℃ increase in temperature. The average coefficient of linear thermal expansion α of the circuit connection component 4 between 30℃ and 120℃ is... L The following calculation is performed: the change in linear thermal expansion L(t) [unit: μm / 10mm] of the circuit connection component 4 measured by the above method at t = 30℃ to 120℃ is converted into the linear thermal expansion (μm) of 1m length of the circuit connection component 4, and the average value for each 1℃ increase in temperature is calculated from this converted value (i.e., calculated according to the following formula).

[0036] α L ={L(t=120℃)-L(t=30℃)}×100 / (120-30)

[0037] The cured adhesive component 9 and conductive particles 10 constituting the circuit connection member 4 are selected in a manner that gives the circuit connection member 4 the aforementioned properties. The circuit connection member 4 is obtained, for example, by curing an adhesive composition containing the adhesive component and conductive particles 10. From the viewpoint of suppressing the peeling of the circuit connection member 4 from the circuit components 2, 3 and the circuit electrodes 6, 8, the adhesive composition is preferably such that the linear thermal expansion l(t) of the cured adhesive composition at temperature t satisfies the condition dl(t) / dt < 0 at at least any temperature t between t = 30°C and 120°C. The cured adhesive composition can, for example, be a cured product obtained by molding the adhesive composition into a film-like adhesive with a thickness of 100 ± 20 μm and heating the film-like adhesive at 180°C for 1 hour.

[0038] The linear thermal expansion l(t) of the cured adhesive composition was determined as follows: using a thermomechanical analysis apparatus, with a sample length of 10 mm, a width of 4 mm, and a thickness of 0.1 mm, and a load of 5 gf (per 0.4 mm of the sample). 2 Under the conditions of cross-sectional area and heating rate of 5℃ / min, in the temperature range of t=0℃~200℃, the linear thermal expansion at temperature t=0℃ is set as l(0)=0μm, and the linear thermal expansion at temperature t℃ is measured every 0.1℃. The linear thermal expansion here refers to the linear thermal expansion in the length direction of the sample.

[0039] From the viewpoint of inhibiting the peeling of the cured adhesive composition (circuit connection member 4) from the circuit members 2, 3 and the circuit electrodes 6, 8, the linear thermal expansion l(t) of the cured adhesive composition satisfies the condition dl(t) / dt≤-0.01, more preferably dl(t) / dt≤-0.1, and even more preferably dl(t) / dt≤-0.5 at at least any temperature t between t = 30°C and 120°C.

[0040] From the viewpoint of inhibiting the peeling of the cured adhesive composition (circuit connection member 4) from the circuit members 2, 3 and the circuit electrodes 6, 8, the linear thermal expansion l(t) of the cured adhesive composition satisfies the above-mentioned dl(t) / dt condition at at least any temperature t, preferably t = 30°C to 100°C, more preferably t = 30°C to 90°C, and even more preferably t = 30°C to 80°C.

[0041] From the viewpoint of inhibiting the peeling of the cured adhesive composition (circuit connection member 4) from the circuit members 2, 3 and the circuit electrodes 6, 8, the average linear thermal expansion coefficient of the cured adhesive composition at 30°C to 120°C is preferably less than or equal to 500 ppm / °C, more preferably less than or equal to 250 ppm / °C, and even more preferably less than or equal to 150 ppm / °C.

[0042] The coefficient of linear thermal expansion (ppm / °C) of a cured adhesive composition is defined as the amount of linear thermal expansion (μm) of a 1-meter length of the cured adhesive composition per 1°C increase in temperature. The average coefficient of linear thermal expansion α of the cured adhesive composition between 30°C and 120°C is... l The following calculation is performed: the change in linear thermal expansion l(t) [unit: μm / 10mm] of the cured adhesive composition measured according to the above method at t = 30℃ to 120℃ is converted into the linear thermal expansion (μm) of 1m length of the cured adhesive composition, and the average value per 1℃ increase in temperature is calculated from this converted value (i.e., calculated according to the following formula).

[0043] α l ={l(t=120℃)-l(t=30℃)}×100 / (120-30)

[0044] Adhesive compositions exhibiting this characteristic may contain, for example, two or more resin components with different glass transition temperatures (Tg), components that readily undergo phase separation, components with easily oriented backbones, and filler components with negative coefficients of linear thermal expansion. Examples of combinations of components readily undergoing phase separation include combinations of components with large differences in molecular weight and combinations of components with large differences in polarity. Specifically, combinations of components readily undergoing phase separation may include combinations of acrylic resin and epoxy resin, combinations of polyurethane resin and phenoxy resin, combinations of acrylic rubber and phenoxy resin, and combinations of acrylic rubber and epoxy resin. Examples of components with easily oriented backbones include components containing alkyl chains and components containing phenyl groups. The inventors believe that by including the components described above in the adhesive composition, shrinkage (volume phenomenon) occurs in the cured adhesive composition (circuit connection member 4) due to the reduction of micropores caused by temperature rise, reorientation of molecular chains, and reconfiguration of filler components.

[0045] In one embodiment, the adhesive composition preferably contains: (a) a thermoplastic resin (hereinafter also referred to as "(a) component"), (b) a free radical polymerizable compound (hereinafter also referred to as "(b) component"), and (c) a free radical polymerization initiator (hereinafter also referred to as "(c) component").

[0046] As for component (a), there are no particular limitations, for example, one or more resins selected from polyimide resin, polyamide resin, phenoxy resin, poly(meth)acrylic resin, polyester resin, polyurethane resin, polyester polyurethane resin and polyvinyl butyral resin may be listed.

[0047] From the viewpoint of easily obtaining a cured product (circuit connection member 4) of the adhesive composition having the desired linear thermal expansion, the adhesive composition preferably contains two or more of the above-mentioned thermoplastic resins, and more preferably contains two or more thermoplastic resins with different Tg values. Suitable resin combinations include, for example, combinations of phenoxy resin and poly(meth)acrylic resin, combinations of phenoxy resin and polyester resin, combinations of phenoxy resin and polyester polyurethane resin, and combinations of phenoxy resin and polyimide resin.

[0048] When the adhesive composition contains two or more thermoplastic resins with different Tg values, from the viewpoint of easily obtaining a cured adhesive composition (circuit connection member 4) with the desired linear thermal expansion, the ratio (mass ratio: high Tg / low Tg) of the content of the thermoplastic resin with higher Tg to that with lower Tg is preferably 90 / 10 to 10 / 90, more preferably 90 / 10 to 20 / 80, and even more preferably 90 / 10 to 30 / 70. When the adhesive composition contains three or more thermoplastic resins with different Tg values, the adhesive composition preferably contains them in such a way that the ratio of the content of the thermoplastic resin with the highest Tg to that with the thermoplastic resin with the lowest Tg is as described above.

[0049] The weight-average molecular weight of the thermoplastic resin is preferably greater than or equal to 5,000, more preferably greater than or equal to 10,000, and preferably less than or equal to 400,000, more preferably less than or equal to 200,000, and even more preferably less than or equal to 150,000. If the weight-average molecular weight of the thermoplastic resin is greater than or equal to 5,000, the adhesive strength of the adhesive composition tends to be improved. If the weight-average molecular weight of the thermoplastic resin is less than or equal to 400,000, it tends to have excellent compatibility with other components and improved flowability of the adhesive. In this invention, the weight-average molecular weight refers to the weight-average molecular weight (converted from standard polystyrene) determined by GPC (gel permeation chromatography).

[0050] From the viewpoint of stress relief and further improvement of adhesion, the adhesive composition may also contain a rubber component as a thermoplastic resin. 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 butadiene rubber, hydroxyl-terminated poly(oxypropylene) rubber, alkoxysilyl-terminated poly(oxypropylene) rubber, poly(oxytetramethylene) glycol rubber, polyolefin glycol rubber, and poly-ε-caprolactone rubber. From the viewpoint of further improving adhesion, the rubber component preferably has cyano or carboxyl groups as highly polar groups as side chain groups or terminal groups. These rubber components may be used alone or in combination of two or more.

[0051] The rubber component can also be formed into particles. The average particle size of the rubber particles is preferably less than twice the average particle size of the conductive particles 10, for example, 0.01 μm to 100 μm. The storage modulus of the rubber particles at room temperature (25°C) is preferably less than half the storage modulus of the conductive particles 10 and the adhesive composition at room temperature, for example, 0.1 MPa to 100 MPa. From the viewpoint of excellent solvent resistance and easy dispersion in the adhesive composition, the rubber particles are preferably three-dimensionally cross-linked rubber particles.

[0052] Relative to the combined mass of components (a) and (b) of 100 parts by mass, the content of component (a) is preferably greater than or equal to 20 parts by mass, more preferably greater than or equal to 30 parts by mass, even more preferably greater than or equal to 35 parts by mass, and preferably less than or equal to 80 parts by mass, more preferably less than or equal to 70 parts by mass, and even more preferably less than or equal to 65 parts by mass. If the content of component (a) is greater than or equal to 20 parts by mass, there is a tendency for further improvement in adhesive strength and film-forming properties of the adhesive composition; if it is less than or equal to 80 parts by mass, there is a tendency for improved flowability of the adhesive.

[0053] (b) There are no particular restrictions on the ingredients, such as the compounds (monomers) described below, oligomers of the compounds, or both.

[0054] (b) The preferred component is a polyfunctional (meth)acrylate compound having two or more (meth)acryloyloxy groups. Examples of such (meth)acrylate compounds include: epoxy (meth)acrylates, urethane (meth)acrylates, polyether (meth)acrylates, polyester (meth)acrylates, trimethylolpropane tri(meth)acrylate, polyethylene glycol di(meth)acrylate, and other polyalkylene glycol di(meth)acrylates; dicyclopentenyl (meth)acrylate, dicyclopentenyl (meth)acrylate ethyl ester, neopentyl glycol di(meth)acrylate, dipentaerythritol hexa(meth)acrylate, isocyanuric acid modified difunctional (meth)acrylates, isocyanuric acid modified trifunctional (meth)acrylates, etc. Examples of epoxy (meth)acrylates include: epoxy (meth)acrylates formed 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 formed by adding ethylene glycol and / or propylene glycol to the two glycidyl groups of bisphenol fluorene diglycidyl ether. Among these (meth)acrylate compounds, urethane (meth)acrylates are preferred from the viewpoint of obtaining better adhesive properties through the presence of urethane bonds. These compounds can be used alone or in combination of two or more.

[0055] From the perspective of flowability adjustment, adhesive compositions may 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 so on. Isodecyl acrylate, isooctyl (meth)acrylate, n-dodecyl (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-containing (meth)acrylates, and (meth)acryloylmorpholine obtained by reacting (meth)acrylate with one glycidyl group of an epoxy resin having multiple glycidyl groups. These compounds can be used alone or in combination of two or more.

[0056] From the perspective of improving crosslinking rate, adhesive compositions may contain compounds having 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.

[0057] For the purpose of improving adhesive strength, the adhesive composition preferably contains a radical polymerizable compound having a phosphate ester structure as component (b). The radical polymerizable compound having a phosphate ester structure can be, for example, a compound represented by the following formula (1), (2) or (3).

[0058] [Chemistry 1]

[0059]

[0060] 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 2a and b can be the same or different from each other.

[0061] [Chemistry 2]

[0062]

[0063] 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 or different from each other.

[0064] [Chemistry 3]

[0065]

[0066] 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 or different from each other.

[0067] Examples of free radical polymerizable compounds with phosphate ester structures include: (meth)acrylate phosphoroyloxyethyl ester, (meth)acrylate phosphoroyloxypropyl ester, phosphoroyloxypolyoxyethylene glycol mono(meth)acrylate, phosphoroyloxypolyoxypropylene glycol mono(meth)acrylate, 2,2'-di(meth)acryloyloxydiethyl phosphate, EO (ethylene oxide) modified di(meth)acrylate, phosphate modified epoxy (meth)acrylate, and ethylene phosphate.

[0068] Relative to the combined mass of components (a) and (b) of 100 parts by mass, the content of component (b) in the adhesive composition is preferably greater than or equal to 20 parts by mass, more preferably greater than or equal to 30 parts by mass, even more preferably greater than or equal to 35 parts by mass, and preferably less than or equal to 80 parts by mass, more preferably less than or equal to 70 parts by mass, and even more preferably less than or equal to 65 parts by mass. If the content of component (b) is greater than or equal to 20 parts by mass, there is a tendency to improve the heat resistance of the cured adhesive composition (circuit connection member 4), and if it is less than or equal to 80 parts by mass, there is a tendency to further suppress the peeling of the circuit connection member 4 under high temperature and high humidity conditions.

[0069] When the adhesive composition 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 is preferably greater than or equal to 0.1 parts by mass, more preferably greater than or equal to 0.5 parts by mass, and preferably less than or equal to 15 parts by mass, more preferably less than or equal to 10 parts by mass, relative to the total mass of components (a) and (b). If the content of the free radical polymerizable compound with a phosphate ester structure is greater than or equal to 0.1 parts by mass, the adhesive strength of the adhesive composition tends to be further increased; if it is less than or equal to 15 parts by mass, the physical properties of the cured adhesive composition (circuit connection member 4) are less likely to decrease, and the reliability tends to be improved.

[0070] As component (c), compounds such as peroxides and azo compounds can be arbitrarily selected. 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 until the concentration of the compound decreases to half its initial value at a predetermined temperature.

[0071] Free radical polymerization initiators can be, for example, one or more compounds selected from the following: 1,1,3,3-tetramethylbutyl peroxyneodecanate, di(4-tert-butylcyclohexyl)peroxydicarbonate, di(2-ethylhexyl)peroxydicarbonate, cumyl peroxyneodecanate, 1,1,3,3-tetramethylbutyl peroxyneodecanate, dilauroyl peroxide, 1-cyclohexyl-1-methylethyl peroxyneodecanate, tert-hexyl peroxyneodecanate, tert-butyl peroxyneodecanate, tert-butyl peroxyneodecanate, 1,1,3,3-tetramethylbutyl peroxyneodecanate, etc. 2-Ethylhexanoate peroxide, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxide)hexane, tert-hexyl peroxide-2-ethylhexanoate, tert-butyl peroxide-2-ethylhexanoate, tert-butyl peroxide-neoheptanoate, tert-pentyl peroxide-2-ethylhexanoate, di-tert-butyl peroxide-6-tert-butyl peroxide, tert-pentyl peroxide-3,5,5-trimethylhexanoate, 3-hydroxy-1,1-dimethylbutyl peroxide-neodecanate, 1,1,3,3-tetramethylbutyl peroxide-2-ethylhexanoate, tert-pentyl peroxide-neodecanate, peroxide-2- tert-amyl ethylhexanoate, 3-methylbenzoyl peroxide, 4-methylbenzoyl peroxide, di(3-methylbenzoyl) peroxide, benzoyl 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-cyclopentanonitrile) (Hexaneformonitrile), tert-hexyl isopropyl percarbonate, tert-butyl maleic peroxide, tert-butyl peroxide-3,5,5-trimethylhexanoate, tert-butyl peroxylaurate, 2,5-dimethyl-2,5-di(3-methylbenzoyl peroxide)hexane, tert-butyl peroxide-2-ethylhexyl monocarbonate, tert-hexyl peroxide, 2,5-dimethyl-2,5-di(benzoyl peroxide)hexane, tert-butyl peroxide, dibutyl trimethyl adipate, tert-pentyl peroxide, tert-pentyl peroxide, and tert-pentyl peroxide.

[0072] From the viewpoint of suppressing corrosion of circuit electrodes 6 and 8, the chloride ion or organic acid content in the free radical polymerization initiator is preferably less than or equal to 5000 ppm. Furthermore, it is more preferable to use a free radical polymerization initiator that produces less organic acid upon decomposition. From the viewpoint of improving the stability of the adhesive composition, it is preferable to use a free radical polymerization initiator that retains a mass percentage of greater than or equal to 20% by mass after being exposed to air at room temperature (25°C) and atmospheric pressure for 24 hours.

[0073] Relative to the total amount of components (a) and (b) 100 parts by mass, the content of component (c) in the adhesive composition is preferably greater than or equal to 1 part by mass, more preferably greater than or equal to 2.5 parts by mass, and preferably less than or equal to 15 parts by mass, more preferably less than or equal to 10 parts by mass.

[0074] In another embodiment, the adhesive composition preferably contains: (a) a thermoplastic resin, (d) an epoxy resin (hereinafter also referred to as "component (d)"), and (e) a curing agent (hereinafter also referred to as "component (e)"). Component (a) in this embodiment is the same as component (a) described in the embodiments above.

[0075] (d) An epoxy resin is a resin having at least one epoxy group in its molecule. Examples of epoxy resins include: bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenolic varnish type epoxy resin, cresol phenolic varnish type epoxy resin, bisphenol A phenolic varnish type epoxy resin, bisphenol F phenolic varnish type epoxy resin, alicyclic epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, and aliphatic chain epoxy resin. (d) The epoxy resin may be a halogenated epoxy resin obtained by halogenating the above-mentioned epoxy resins, or a hydrogenated epoxy resin obtained by hydrogenating the above-mentioned epoxy resins. These epoxy resins, halogenated epoxy resins, and hydrogenated epoxy resins may be used alone or in combination of two or more.

[0076] Relative to the combined mass of components (a) and (d) of 100 parts by mass, the content of component (d) in the adhesive composition is preferably greater than or equal to 10 parts by mass, more preferably greater than or equal to 20 parts by mass, even more preferably greater than or equal to 30 parts by mass, and preferably less than or equal to 90 parts by mass, more preferably less than or equal to 80 parts by mass, and even more preferably less than or equal to 70 parts by mass. If the content of component (d) is greater than or equal to 10 parts by mass, there is a tendency to obtain better adhesion; if it is less than or equal to 90 parts by mass, there is less tackiness and a tendency to improve workability.

[0077] (e) The curing agent (also known as an "epoxy polymerization initiator" or "latent curing agent") can be any curing agent capable of curing the epoxy resin in (d). Examples of curing agents include anionic polymeric catalyst-type curing agents, cationic polymeric catalyst-type curing agents, and addition polymeric curing agents. They can be used alone or in combination of two or more. From the viewpoint of excellent rapid curing performance and without needing to consider stoichiometry, the curing agent in (e) is preferably an anionic or cationic catalyst-type curing agent.

[0078] Examples of catalyst-type curing agents that can be used for anionic or cationic polymerization include: imidazole curing agents, hydrazide curing agents, boron trifluoride-amine complexes, sulfonium salts, diazo-onium salts and other onium salts, aminoimides, diaminomaleonitrile, melamine and its derivatives, polyamine salts, dicyandiamide, etc. Modified versions of these can also be used.

[0079] When using compounds containing tertiary amines, imidazole compounds, etc., as anionic polymerizable catalyst-type curing agents, epoxy resins are cured by heating at a temperature of 160°C to 200°C for tens of seconds to several hours. Therefore, the pot life of the adhesive composition can be extended. As cationic polymerizable catalyst-type curing agents, photosensitive onium salts (aromatic diazonium salts, aromatic sulfonium salts, etc.) that cure epoxy resins by energy beam irradiation are preferred, for example. Aliphatic sulfonium salts are examples of cationic polymerizable catalyst-type curing agents that are activated and cured by heating. From the perspective of rapid curing, these anionic or cationic polymerizable catalyst-type curing agents are preferred.

[0080] Examples of addition polymerization curing agents include polyamines, polythiols, polyphenols, and acid anhydrides.

[0081] From the perspective of obtaining a longer service life, it is preferable to use microencapsulated curing agents that are coated with polymers such as polyurethane and polyester, metal films such as nickel and copper, or inorganic materials such as calcium silicate (latent curing agents) and microencapsulated.

[0082] Relative to the total amount of components (a) and (d) 100 parts by mass, the content of component (e) in the adhesive composition is preferably greater than or equal to 20 parts by mass, more preferably greater than or equal to 30 parts by mass, and preferably less than or equal to 80 parts by mass, more preferably less than or equal to 70 parts by mass.

[0083] Examples of conductive particles 10 include: metal particles such as Au, Ag, Ni, Cu, and solder; conductive carbon particles, and other conductive particles. The conductive particles 10 can be coated conductive particles, comprising: a core containing non-conductive glass, ceramic, or plastic particles; and a layer coated with the core and composed of the aforementioned metals, metal particles, conductive carbon particles, etc. When the conductive particles 10 are coated conductive particles or metal particles that melt through heat (thermally molten metal particles), the conductive particles 10 deform due to heating and pressure during circuit connection. Therefore, even if there are height deviations between the circuit electrodes 6 and 8, the contact area between the conductive particles 10 and the circuit electrodes 6 and 8 increases, thereby achieving good reliability. Especially when the amount of conductive particles 10 is increased, from the viewpoint of preventing short circuits between conductive particles 10 and improving the insulation between adjacent first circuit electrodes 6, 6 or second circuit electrodes 8, 8, the conductive particles 10 can be insulating coated conductive particles having the aforementioned conductive particles and an insulating coating layer formed of an insulating material such as a polymer resin covering the surface of the conductive particles. These conductive particles, coated conductive particles, and insulating coated conductive particles can be used alone or in combination of two or more.

[0084] From the viewpoint of excellent dispersibility and conductivity, the average particle size of the conductive particles 10 is preferably 1 μm to 50 μm. Based on the total amount of the adhesive composition, the content of conductive particles is preferably greater than or equal to 0.1% by volume, more preferably less than or equal to 30% by volume, and even more preferably less than or equal to 10% by volume. If the content is greater than or equal to 0.1% by volume, there is a tendency to further improve conductivity; if it is less than or equal to 30% by volume, there is a tendency to suppress short circuits between adjacent first circuit electrodes 6, 6 or between second circuit electrodes 8, 8. The content of conductive particles 10 is determined based on the volume of each component of the adhesive composition (before curing) at 23°C. The volume of each component can be, for example, a value obtained by converting weight to volume using specific gravity. Alternatively, for example, a suitable solvent (water, alcohol, etc.) that does not dissolve or swell the component but sufficiently wets it can be added to a measuring cylinder or the like, and the increased volume can be used as the volume of the component.

[0085] In addition to components (a), (b), (c) and conductive particles 10, or components (a), (d), (e) and conductive particles 10, the adhesive composition may further contain other resins such as phenolic resin and melamine resin, fillers, softeners, curing accelerators, anti-aging agents, colorants, flame retardants, thixotropic agents, coupling agents and other adhesion enhancers, thickeners, leveling agents, weather resistance enhancers, isocyanate compounds, etc.

[0086] The filler 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 of these particles is preferably less than half the average particle size of the conductive particles 10, for example, 0.005 μm to 25 μm. When the adhesive composition contains non-conductive particles (e.g., the rubber particles described above), the average particle size of the particles used as fillers can be less than or equal to the average particle size of the non-conductive particles.

[0087] From the viewpoint of further improving the electrical properties, such as the connection reliability between circuit electrodes 6 and 8, through the cured product (circuit connection member 4) of the adhesive composition having the desired linear thermal expansion, the filler is preferably a filler with a negative average coefficient of linear thermal expansion at 30°C to 120°C. Examples of fillers with a negative average coefficient of linear thermal expansion at 30°C to 120°C include particles composed of zirconium compounds.

[0088] Relative to 100 parts by weight of the adhesive composition, the filler content is preferably greater than or equal to 5 parts by weight, and more preferably less than or equal to 60 parts by weight. If the content is less than or equal to 60 parts by weight, there is a tendency to obtain a more sufficient effect of improved connection reliability, and if it is greater than or equal to 5 parts by weight, there is a tendency to obtain a sufficient effect of added filler.

[0089] Coupling agents can be, for example, silane coupling agents. By using coupling agents such as silane coupling agents, the adhesion of the adhesive composition can be further improved. Examples of silane coupling agents include: vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, and their condensates.

[0090] Relative to 100 parts by weight of the adhesive component (e.g., components (a) to (e)) in the adhesive composition, the content of the coupling agent is preferably greater than or equal to 0.1 parts by weight, more preferably greater than or equal to 0.25 parts by weight, and preferably less than or equal to 10 parts by weight, more preferably less than or equal to 5 parts by weight. If the content of the coupling agent is greater than or equal to 0.1 parts by weight, there is a tendency to further suppress the delamination between the circuit component and the circuit connection component; if the content of the coupling agent is less than or equal to 10 parts by weight, there is a tendency to extend the usable time of the adhesive composition.

[0091] If the adhesive composition is liquid at 15°C to 25°C, it can be used as a paste-like adhesive composition. If the adhesive composition is solid at room temperature (25°C), it can be used as a paste-like adhesive composition by heating or by dissolving it in a solvent. There are no particular limitations on the solvent, as long as it is non-reactive with the components of the adhesive composition and exhibits sufficient solubility for those components; a solvent with a boiling point of 50°C to 150°C at atmospheric pressure is preferred. With a boiling point greater than or equal to 50°C, solvent evaporation at room temperature (25°C) can be suppressed, facilitating use in open systems. With a boiling point less than or equal to 150°C, solvent evaporation is facilitated after applying the adhesive composition to circuit components 2 and 3, ensuring reliable bonding.

[0092] Adhesive compositions can also be used as film-like adhesives. For example, an adhesive composition is prepared by coating a solution, to which solvents are added as needed, onto a release liner such as a fluoropolymer film, polyethylene terephthalate film, or release paper; or by impregnating the solution into a substrate such as nonwoven fabric and then placing it on a release liner, followed by removing the solvents to form a film. From an operability point of view, film-like adhesives are suitable for use.

[0093] The adhesive composition can be used as circuit connection materials, such as anisotropic conductive adhesives, silver paste, and silver film, and as semiconductor element bonding materials, such as CSP elastomers, CSP underfill materials, and LOC tapes.

[0094] The connecting structure 1 can be obtained, for example, by arranging the first circuit component 2 and the second circuit component 3 in such a way that the first circuit electrode 6 and the second circuit electrode 8 are opposite to each other, with a film adhesive between the first circuit component 2 and the second circuit component 3, and heating and pressurizing them to electrically connect the first circuit electrode 6 and the second circuit electrode 8 to each other.

[0095] There are no particular limitations on the heating temperature, but it is preferably between 50°C and 250°C. There are no particular limitations on the pressure applied during heating, as long as it does not damage the bonded components (circuit components 2 and 3), but it is preferably between 0.1 MPa and 10 MPa. Heating and pressurizing are preferably performed for 0.5 seconds to 3 hours.

[0096] When connecting circuit components 2 and 3 to each other, from the viewpoint of connecting at a lower temperature and for a shorter time, light irradiation can be performed simultaneously with heating and pressurization. Irradiation is preferably performed using light in the wavelength range of 150nm to 750nm. Examples of suitable light irradiation methods include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, or metal halide lamps, at a wavelength of 0.1J / cm². 2 ~10J / cm 2 The amount of radiation is used to determine the radiation level.

[0097] The cured product of the adhesive composition described above (circuit connection component 4) is, for example, as shown above. Figure 2 As shown in L1, there is a solidified material (circuit connection member) with dl(t) / dt<0 (dL(t) / dt<0) at a temperature of t = 30℃ to 120℃. Therefore, the thermal expansion of the circuit connection member 4 itself as the temperature rises can be reduced, and the peeling interface stress (the stress that is required to peel the circuit connection member 4 from the substrate 5, 7 and the circuit electrodes 6, 8) generated at the interface between the circuit connection member 4 and the substrate 5, 7 and the circuit electrodes 6, 8 can be reduced.

[0098] On the other hand, the cured product (circuit connection component) of conventional adhesive compositions, for example, Figure 2 As shown in L2, the adhesive composition (circuit connection component) is a cured product of an adhesive composition that is always dl(t) / dt≥0 (dL(t) / dt≥0) at temperatures t=30℃~120℃. Therefore, as the temperature rises, the circuit connection component 4 itself is prone to thermal expansion, resulting in large peel interface stress at the interface between the circuit connection component 4 and the substrates 5, 7 and the circuit electrodes 6, 8.

[0099] Therefore, compared to the cured product (circuit connection member) of conventional adhesive compositions, the cured product (circuit connection member 4) of the adhesive composition according to this embodiment can suppress the peeling of the circuit connection member 4 from the substrates 5 and 7 and the circuit electrodes 6 and 8 even when placed in a high temperature and high humidity environment. This effect can also be achieved when using circuit electrodes formed of amorphous materials such as ITO, which are not conducive to adhesion, as the circuit electrodes 6 and 8.

[0100] Example

[0101] The present invention will now be described in more detail based on embodiments, but the present invention is not limited to the embodiments.

[0102] <Synthesis of Polyurethane Resins>

[0103] In a separable flask equipped with a reflux condenser, thermometer, and stirrer, 1000 parts by mass of polypropylene glycol (number average molecular weight: 2000), a glycol with ether bonds, and 4000 parts by mass of methyl ethyl ketone, a solvent, were added, and the mixture was stirred at 40°C for 30 minutes. The solution was then heated to 70°C, and 0.127 parts by mass of dimethyltin laurylate, a catalyst, were added. Next, a solution prepared by dissolving 125 parts by mass of 4,4'-diphenylmethane diisocyanate in 125 parts by mass of methyl ethyl ketone was added dropwise over 1 hour. The mixture was then stirred continuously at 70°C until no absorption peak originating from the NCO group was observed by an infrared spectrophotometer, thereby obtaining a methyl ethyl ketone solution of polyurethane resin. The amount of methyl ethyl ketone was then adjusted so that the solids concentration (concentration of polyurethane resin) of this solution was 30% by mass.

[0104] The obtained polyurethane resin has a glass transition temperature (Tg) of -20℃. The glass transition temperature (Tg) was determined using a thermomechanical analysis apparatus.

[0105] The obtained polyurethane resin had a weight-average molecular weight of 320,000. The weight-average molecular weight is a conversion value to standard polystyrene determined using GPC (gel permeation chromatography). The analytical conditions for GPC are shown in Table 1 below.

[0106] [Table 1]

[0107]

[0108] <Synthesis of Carbamate Acrylates>

[0109] In a 2L four-necked flask equipped with a thermometer, stirrer, inactive 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 the reaction solution. For the reaction solution heated to 70°C, 666 parts by mass of isophorone diisocyanate (IPDI) were added dropwise uniformly over 3 hours to allow the reaction to proceed. After the addition was complete, the reaction was continued for 15 hours. The reaction was stopped when the content of NCO groups was less than or equal to 0.2% by mass, as confirmed by an automatic potentiometric titration device (product name AT-510, manufactured by Kyoto Electronics Industry Co., Ltd.), to obtain urethane acrylate. The weight average molecular weight of the urethane acrylate was 8500. It should be noted that the weight average molecular weight of the urethane acrylate was determined in the same manner as that of the polyurethane resin described above.

[0110] <Preparation of Film-like Adhesives>

[0111] The adhesive composition is obtained by mixing the following ingredients in the mass ratios shown in Tables 2 and 3.

[0112] (Thermoplastic resin)

[0113] Al: Phenoxy resin (product name: PKHC, manufactured by Union Carbide Corporation, weight average molecular weight 45000, Tg: 90℃, bisphenol A backbone)

[0114] A2: Phenoxy resin (product name: YD-6020, manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., weight average molecular weight 5000, Tg: 70℃, bisphenol A / bisphenol F backbone)

[0115] A3: Phenoxy resin (product name: FX-316, manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., weight average molecular weight 50,000, Tg: 70℃, bisphenol F backbone)

[0116] A4: Phenoxy resin (Product name: FX-293AT40, manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., Tg: 160℃, high heat resistance skeleton)

[0117] A5: Polyurethane resin synthesized as described above

[0118] A6: Polyester resin (Product name: UE-3400, manufactured by Unitika Co., Ltd., Tg: -20℃)

[0119] A7: Polyester resin (Product name: UE-3200, manufactured by Unitika Co., Ltd., Tg: 70℃)

[0120] (Free radical polymeric compounds)

[0121] B1: Carbamate acrylate synthesized as described above

[0122] B2: Isocyanuric acid EO-modified diacrylate (Product name: M-215, manufactured by Toa Synthetic Co., Ltd.)

[0123] B3: 2-Methacryloyloxyethyl acid phosphate (Product name: Light Ester P-2M, manufactured by Kyoei Chemical Co., Ltd.)

[0124] It should be noted that, of the above ingredients, the solid components are used after being prepared into a 40% by mass solution by dissolving 40g of the solid component in 60g of methyl ethyl ketone.

[0125] (Free radical polymerization initiator)

[0126] C1: Lauroyl peroxide (Product name: PEROYL L, manufactured by Nippon Oil Co., Ltd., molecular weight 398.6)

[0127] (filler)

[0128] D1: Silica microparticles (Product name: R104, manufactured by Aerosil Corporation of Japan, primary particle size: 12nm)

[0129] (Silane coupling agent)

[0130] E1: 3-Methacryloxypropyltrimethoxysilane (Product name: KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0131] It should be noted that the silica microparticles are used after preparing a 10% by mass dispersion in a mixed solvent of 10g silica microparticles and 45g toluene and 45g ethyl acetate.

[0132] Next, conductive particles with an average particle size of 5 μm and a specific gravity of 2.5 were prepared, having a nickel layer with a thickness of 0.2 μm on the surface of polystyrene particles (core). These conductive particles were dispersed in each adhesive composition at a ratio of 1.5% by volume to obtain a coating liquid. Using a coating apparatus, the coating liquid was applied to a 50 μm thick polyethylene terephthalate (PET) film. The coating film was then hot-air dried at 70°C for 10 minutes to obtain a film-like adhesive with a thickness of 18 μm.

[0133] <Construction of Connecting Structures>

[0134] A flexible printed circuit board (FPC) with approximately 2200 copper circuit electrodes, each 75 μm wide, 150 μm pitch, and 18 μm thick, is bonded to a glass (SiO2) substrate (product name: PreClean glass slide S7224, manufactured by Matsunami Glass Industry Co., Ltd.) or a glass substrate with an amorphous indium tin oxide (ITO) film (manufactured by Geomatec Corporation). The aforementioned film adhesives are applied between the FPC and the glass substrate or the glass substrate with amorphous ITO. The bonding is performed using a thermoforming device (heating method: constant temperature type, manufactured by Toray Engineering Co., Ltd.), through heating and pressurizing at 160°C, 3 MPa, for 5 seconds. The pressure applied during the pressurization is such that the bonding area is set to 0.495 cm². 2 The calculation was performed. Thus, a connection structure was obtained in which the FPC and a glass substrate or a glass substrate with amorphous ITO were connected over a width of 1.5 mm via a cured film adhesive.

[0135] <Determination of Linear Thermal Expansion>

[0136] Multiple layers of the aforementioned film-like adhesive were laminated using a laminator to a thickness of 100±20 μm, and then heated in an oven at 180°C for 1 hour to produce cured samples. The cured samples were analyzed using a thermomechanical analysis apparatus (manufactured by Shimadzu Corporation) at a length of 10 mm and a width of 4 mm, with a load of 5 gf (per 0.4 mm of sample). 2 Under conditions of cross-sectional area and heating rate of 5℃ / min, the linear thermal expansion l(t) μm was measured every 0.1℃ from t = 0℃ to 200℃. The linear thermal expansion l(t) was measured with the linear thermal expansion l(0) at t = 0℃ set to 0 μm. Based on the measurement results, it was determined whether there was a temperature region where dl(t) / dt < 0 at t = 30℃ to 120℃ (in cases where this temperature region and the minimum value of dl(t) / dt were determined). In addition, the average linear thermal expansion coefficient (ppm / ℃) from 30℃ to 120℃ was calculated based on the measurement results. The results are shown in Tables 2 and 3.

[0137] <Evaluation of whether or not peeling occurred>

[0138] Regarding the connection structures fabricated in the above manner, the appearance of the connections was observed using an optical microscope immediately after connection and after a high-temperature and high-humidity test at 85°C and 85% RH for 250 hours. The area of ​​delamination at the substrate-resin interface of the spacer portion (the portion between the electrode terminals of the FPC) was measured. A delamination area exceeding 30% of the total spacer area was evaluated as "present," and a delamination area less than or equal to 30% was evaluated as "no." The results are shown in Tables 2 and 3.

[0139] [Table 2]

[0140]

[0141] [Table 3]

[0142]

[0143] It is confirmed from the above that, compared with the circuit connection components of Comparative Examples 1 to 9, the circuit connection components of Examples 1 to 7 can suppress the occurrence of delamination even under high temperature and high humidity conditions.

[0144] Symbol Explanation

[0145] 1: Connecting structure; 2: First circuit component; 3: Second circuit component; 4: Circuit connecting component; 6: First circuit electrode; 8: Second circuit electrode; 10: Conductive particle.

Claims

1. A connection structure comprising: a first circuit member having a first circuit electrode; a second circuit member having a second circuit electrode; and a circuit connection member disposed between the first circuit member and the second circuit member and electrically connecting the first circuit electrode and the second circuit electrode to each other. The circuit connection component is a cured product of an adhesive composition containing two or more thermoplastic resins. The thermoplastic resin includes phenoxy resin. The linear thermal expansion L(t) of the circuit connection component at temperature t satisfies the condition that dL(t) / dt < 0 at at least any temperature t between t = 30℃ and 120℃. The adhesive composition does not contain a combination of polyurethane resin and phenoxy resin.

2. The connecting structure according to claim 1, wherein the adhesive composition further comprises a free radical polymerizable compound. The free radical polymerizable compound contains urethane (meth)acrylate.

3. The connecting structure according to claim 1 or 2, wherein the adhesive composition further comprises filler.

4. The connecting structure according to claim 1 or 2, wherein the adhesive composition further comprises a silane coupling agent.

5. The connecting structure according to claim 1 or 2, wherein the adhesive composition further comprises a free radical polymerizable compound. The free radical polymerizable compounds include free radical polymerizable compounds having a phosphate ester structure.

6. The connection structure according to claim 1 or 2, wherein the average linear thermal expansion coefficient of the circuit connection component at 30°C to 120°C is less than or equal to 500ppm / °C.

7. A circuit connection component, said circuit connection component being a cured product of an adhesive composition containing two or more thermoplastic resins. The thermoplastic resin includes phenoxy resin. The linear thermal expansion L(t) of the circuit connection component at temperature t satisfies the condition that dL(t) / dt < 0 at at least any temperature t between t = 30℃ and 120℃. The adhesive composition does not contain a combination of polyurethane resin and phenoxy resin.

8. The circuit connection component according to claim 7, wherein the adhesive composition further comprises a free radical polymerizable compound. The free radical polymerizable compound contains urethane (meth)acrylate.

9. The circuit connection member according to claim 7 or 8, wherein the adhesive composition further comprises filler.

10. The circuit connection member according to claim 7 or 8, wherein the adhesive composition further comprises a silane coupling agent.

11. The circuit connection member according to claim 7 or 8, wherein the adhesive composition further comprises a free radical polymerizable compound. The free radical polymerizable compounds include free radical polymerizable compounds having a phosphate ester structure.

12. The circuit connection component according to claim 7 or 8, wherein the average linear thermal expansion coefficient of the circuit connection component at 30°C to 120°C is less than or equal to 500ppm / °C.

13. An adhesive composition comprising two or more thermoplastic resins. The thermoplastic resin includes phenoxy resin. The linear thermal expansion l(t) of the cured adhesive composition at temperature t satisfies the condition that dl(t) / dt < 0 at at least any temperature t between t = 30℃ and 120℃. The adhesive composition does not contain a combination of polyurethane resin and phenoxy resin.

14. The adhesive composition according to claim 13, further comprising a free radical polymerizable compound. The free radical polymerizable compound contains urethane (meth)acrylate.

15. The adhesive composition according to claim 13 or 14, further comprising filler.

16. The adhesive composition according to claim 13 or 14, further comprising a silane coupling agent.

17. The adhesive composition according to claim 13 or 14, further comprising a free radical polymerizable compound. The free radical polymerizable compounds include free radical polymerizable compounds having a phosphate ester structure.

18. The adhesive composition according to claim 13 or 14, wherein the cured product has an average linear thermal expansion coefficient of less than or equal to 500 ppm / ℃ at 30℃ to 120℃.

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