Adhesive film for circuit connection, circuit connection structure, and method for producing the same

Abstract

To provide an adhesive film for circuit connection having sufficient transferability, and also to provide a circuit connection structure and a method for producing the circuit connection structure using the adhesive film for circuit connection.SOLUTION: An adhesive film for circuit connection includes a radically polymerizable compound, a polymerization initiator, and conductive particles, wherein the radically polymerizable compound has a linear alkyl structure, and the radically polymerizable compound has a melting point from 0°C to 60°C. In another form, an adhesive film for circuit connection includes a radically polymerizable compound, a polymerization initiator, and conductive particles, wherein the radically polymerizable compound has a linear alkyl structure, and the linear alkyl structure has a carbon number from 12 to 22.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an adhesive film for circuit connection, a circuit connection structure, and a method for manufacturing the same.

Background Art

[0002] A driving IC is mounted on a panel such as a liquid crystal display device. As a mounting method, there is COF (Chip-on-Film, or Chip-on-Flexible) mounting. In COF mounting, a driving IC such as a semiconductor chip is bonded onto a film-shaped wiring circuit board, and these are bonded to a glass panel. For bonding between COF and a glass panel, an anisotropic conductive adhesive film is used (see, for example, Patent Document 1 below).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is desirable to transfer the adhesive film to COF continuously in a short time at low temperature and low pressure. When transferring the adhesive film to COF, an alignment recognition device checks for the presence or absence of bubbles in the alignment mark portion to determine whether the transfer is sufficient. If there is no abnormality, the adhesive film can be continuously transferred to COF. However, if bubbles remain between COF and the adhesive film and the transfer of the adhesive film is insufficient, an error occurs, the transfer operation of the adhesive film to COF is interrupted, and the transfer of the adhesive film cannot be performed in a short time.

[0005] Therefore, one aspect of the present invention aims to provide an adhesive film for circuit connection having sufficient transferability. Another aspect of the present invention aims to provide a circuit connection structure using the adhesive film for circuit connection and a method for manufacturing the circuit connection structure.

Means for Solving the Problems

[0006] The present invention includes, for example, the following [1] to

[15] . [1] Containing a radically polymerizable compound, a polymerization initiator, and conductive particles, An adhesive film for circuit connection, wherein the radically polymerizable compound contains a radically polymerizable compound A1 having a linear alkyl structure and a melting point of 0 to 60°C. [2] The adhesive film for circuit connection according to [1], wherein the number of carbon atoms in the linear alkyl structure is 12 to 22. [3] The adhesive film for circuit connection according to [1] or [2], wherein the radically polymerizable compound A1 is a (meth)acrylate compound. [4] The adhesive film for circuit connection according to any one of [1] to [3], wherein the content of the radically polymerizable compound A1 is 1 to 50% by mass based on the total mass of the radically polymerizable compound. [5] Comprising a first adhesive layer and a second adhesive layer laminated on the first adhesive layer, The adhesive film for circuit connection according to any one of [1] to [4], wherein at least one of the first adhesive layer and the second adhesive layer contains the radically polymerizable compound A1. [6] Containing a radically polymerizable compound, a polymerization initiator, and conductive particles, An adhesive film for circuit connection, wherein the radically polymerizable compound contains a radically polymerizable compound A2 having a linear alkyl structure and the number of carbon atoms in the linear alkyl structure is 12 to 22. [7] The adhesive film for circuit connection according to [6], wherein the radically polymerizable compound A2 is a (meth)acrylate compound. [8] The circuit connection adhesive film according to [6] or [7], wherein the content of the radical polymerizable compound A2 is 1 to 50% by mass based on the total mass of the radical polymerizable compounds. [9] comprising a first adhesive layer and a second adhesive layer laminated on the first adhesive layer; The circuit connection adhesive film according to any one of [6] to [8], wherein at least one of the first adhesive layer and the second adhesive layer contains the radical polymerizable compound A2.

[10] The circuit connection adhesive film according to any one of [1] to [9], wherein the radical polymerizable compound further contains a (poly)urethane (meth)acrylate compound.

[11] The circuit connection adhesive film according to any one of [1] to

[10] , further containing a thermoplastic resin.

[12] The circuit connection adhesive film according to any one of [1] to

[11] , further containing a coupling agent.

[13] The circuit connection adhesive film according to any one of [1] to

[12] , further containing a filler.

[14] A first circuit member having a first electrode; A second circuit member having a second electrode; A circuit connection portion disposed between the first circuit member and the second circuit member and electrically connecting the first electrode and the second electrode to each other; comprising; The circuit connection structure, wherein the circuit connection portion includes a cured product of the circuit connection adhesive film according to any one of [1] to

[13] .

[15] A step of preparing a first circuit member having a first electrode, a second circuit member having a second electrode, and a base material-attached circuit connection adhesive film including the circuit connection adhesive film according to any one of [1] to

[13] on a base material; A step of transferring the circuit connection adhesive film from the base material onto the surface of the first circuit member where the first electrode is formed; After arranging the first circuit member, the circuit connection adhesive film, and the second circuit member in this order so that the first electrode and the second electrode face each other, thermocompression bonding the first circuit member and the second circuit member to electrically connect the first electrode and the second electrode to each other; A method for manufacturing a circuit connection structure, comprising:

Advantages of the Invention

[0007] According to the present invention, a circuit connection adhesive film having sufficient transferability can be provided. Further, according to the present invention, a circuit connection structure using the circuit connection adhesive film and a method for manufacturing the circuit connection structure can be provided.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0009] In this specification, a numerical range indicated by "~" represents a range that includes the numerical values described before and after "~" as the minimum value and the maximum value, respectively. In the numerical ranges described step by step in this specification, the upper limit value or the lower limit value of a numerical range at a certain step may be replaced with the upper limit value or the lower limit value of a numerical range at another step. Also, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. Further, the individually described upper limit value and lower limit value can be arbitrarily combined. Also, in this specification, "(meth)acrylate" means at least one of acrylate and the corresponding methacrylate. The same applies to other similar expressions such as "(meth)acryloyl". Also, "(poly)" means both cases with and without the prefix "poly". Also, "A or B" means that either A or B may be included, or both may be included. Also, the materials exemplified below may be used alone or in combination of two or more, unless otherwise specified. The content of each component in the composition means the total amount of the plurality of substances corresponding to each component in the composition, unless otherwise specified, when there are a plurality of substances corresponding to each component in the composition.

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. However, the present invention is not limited to the following embodiments.

[0011] <Circuit connection adhesive film> FIG. 1 is a schematic cross-sectional view showing a circuit connection adhesive film according to an embodiment. As shown in FIG. 1, the circuit connection adhesive film 1 (hereinafter, also simply referred to as "adhesive film 1") includes a first adhesive layer 2 and a second adhesive layer 3 laminated on the first adhesive layer 2.

[0012] (First adhesive layer) The first adhesive layer 2 is made of a cured product of an adhesive composition (the first adhesive composition). The adhesive composition contains (A) a radically polymerizable compound (hereinafter also referred to as the “(A) component”), (B) a polymerization initiator (hereinafter also referred to as the “(B) component”), and (C) conductive particles (hereinafter also referred to as the “(C) component”).

[0013] The first adhesive layer 2 is obtained, for example, by irradiating a layer made of the adhesive composition with light energy to polymerize the (A) component and curing (photo-curing) the adhesive composition. That is, the first adhesive layer 2 is composed of, for example, the conductive particles 4 and an adhesive component 5 obtained by curing components of the adhesive composition other than the conductive particles 4. The adhesive component 5 contains, for example, a radical polymer of the (A) component. The adhesive component 5 may or may not contain unreacted (A) component and (B) component.

[0014] [(A) component: radically polymerizable compound] The (A) component is, for example, a compound that polymerizes by radicals generated by a photo-polymerization initiator upon irradiation with light (for example, ultraviolet light). The (A) component may be any of a monomer, an oligomer, or a polymer. As the (A) component, one kind of compound may be used alone, or a combination of a plurality of kinds of compounds may be used.

[0015] The (A) component has at least one polymerizable group. The polymerizable group may be a radically polymerizable group that reacts with radicals from the viewpoint of further improving the effect of reducing contact resistance and being more excellent in connection reliability. Examples of the radically polymerizable group include a vinyl group, an allyl group, a styryl group, an alkenyl group, an alkenylene group, a (meth)acryloyl group, a maleimide group, and the like.

[0016] (A) The number of polymerizable groups in the component may be 2 or more from the viewpoint of easily obtaining physical properties and crosslinking density necessary for reducing the connection resistance after polymerization, and may be 10 or less from the viewpoint of suppressing the curing shrinkage during polymerization. Suppressing the curing shrinkage during polymerization is preferable in that a uniform and stable film (the first adhesive layer) can be obtained after light irradiation. In the present embodiment, in order to balance the crosslinking density and the curing shrinkage, after using a polymerizable compound having the number of polymerizable groups within the above range, a polymerizable compound having the number of polymerizable groups outside the above range may be additionally used.

[0017] Specific examples of the component (A) include (meth)acrylate compounds, maleimide compounds, vinyl ether compounds, allyl compounds, styrene derivatives, acrylamide derivatives, nadimide derivatives, natural rubbers, isoprene rubbers, butyl rubbers, nitrile rubbers, butadiene rubbers, styrene-butadiene rubbers, acrylonitrile-butadiene rubbers, carboxylated nitrile rubbers, and the like.

[0018] (Meth)acrylate compounds include epoxy (meth)acrylate, (poly)urethane (meth)acrylate, methyl (meth)acrylate, polyether (meth)acrylate, polyester (meth)acrylate, polybutadiene (meth)acrylate, silicone acrylate, ethyl (meth)acrylate, 2-cyanoethyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-hexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, isopropyl (meth)acrylate, hydroxypropyl (meth)acrylate, isobutyl (meth)acrylate, isobornyl (meth)acrylate, isodecyl (meth)acrylate, isooctyl (meth)acrylate, n-lauryl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-(meth)acryloyloxyethyl phosphate, N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, polyethylene glycol di(meth)acrylate, polyalkylene glycol di(meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol (meth)acrylate, dipentaerythritol hexa(meth)acrylate, isocyanuric acid-modified difunctional (meth)acrylate, isocyanuric acid-modified trifunctional (meth)acrylate, tricyclodecanyl acrylate, dimethylol-tricyclodecane diacrylate, 2-hydroxy-1,3-diacryloxypropane, 2,2-bis[4-(acryloxymethoxy)phenyl]propane, 2,2-bis[4-(acryloxypolyethoxy)phenyl]propane, 2,Examples include 2-di(meth)acryloyloxy diethyl phosphate, 2-(meth)acryloyloxyethyl acid phosphate, etc.

[0019] Examples of maleimide compounds include 1-methyl-2,4-bismaleimide benzene, N,N'-m-phenylene bismaleimide, N,N'-p-phenylene bismaleimide, N,N'-m-tolylene bismaleimide, N,N'-4,4-biphenylene bismaleimide, N,N'-4,4-(3,3'-dimethyl-biphenylene) bismaleimide, N,N'-4,4-(3,3'-dimethyldiphenylmethane) bismaleimide, N,N'-4,4-(3,3'-diethyldiphenylmethane) bismaleimide, N,N'-4,4-diphenylmethane bismaleimide, N,N'-4,4-diphenylpropane bismaleimide, N,N'-4,4-diphenyl ether bismaleimide, N,N'-3,3-diphenylsulfone bismaleimide, 2,2-bis(4-(4-maleimidophenoxy)phenyl)propane, 2,2-bis(3-s-butyl-4-8(4-maleimidophenoxy)phenyl)propane, 1,1-bis(4-(4-maleimidophenoxy)phenyl)decane, 4,4'-cyclohexylidene-bis(1-(4 maleimidophenoxy)-2-cyclohexyl)benzene, 2,2'-bis(4-(4-maleimidophenoxy)phenyl)hexafluoropropane, etc.

[0020] Examples of vinyl ether compounds include diethylene glycol divinyl ether, dipropylene glycol divinyl ether, cyclohexane dimethanol divinyl ether, trimethylolpropane trivinyl ether, etc.

[0021] Examples of allyl compounds include 1,3-diallyl phthalate, 1,2-diallyl phthalate, triallyl isocyanurate, etc.

[0022] The adhesive film for circuit connection according to one embodiment of the present invention contains, as component (A), a radically polymerizable compound having a linear alkyl structure and a melting point of 0 to 60°C (hereinafter also referred to as "radically polymerizable compound A1" or "(A1) component"). Further, the adhesive film for circuit connection according to another embodiment of the present invention contains, as component (A), a radically polymerizable compound having a linear alkyl structure and 12 to 22 carbon atoms in the linear alkyl structure (hereinafter also referred to as "radically polymerizable compound A2" or "(A2) component"). When the adhesive film for circuit connection includes a first adhesive layer and a second adhesive layer, at least one of the first adhesive layer and the second adhesive layer contains the (A1) component, and at least one of the first adhesive layer and the second adhesive layer contains the (A2) component.

[0023] When the adhesive film for circuit connection contains at least one of the (A1) component and the (A2) component, the circuit adhesive film has sufficient transferability. For this reason, the present inventor speculates as follows. That is, since the (A1) component has a linear alkyl structure and a melting point of 0 to 60°C, it can be said that the (A1) component has a somewhat bulky structure. Since the (A2) component has a linear alkyl structure and 12 to 22 carbon atoms in the linear alkyl structure, it can also be said that the (A2) component has a somewhat bulky structure. When the adhesive film contains these radically polymerizable compounds, when transferring the adhesive film to a COF or the like, these radically polymerizable compounds present near the surface of the adhesive film spread along the surface of the COF, so it is speculated that the transferability of the adhesive film is improved. However, the mechanism of the present invention is not limited to the above.

[0024] That the radically polymerizable compound has a linear alkyl structure means that the radically polymerizable compound has an alkyl group (excluding cycloalkyl groups) or an alkylene group. The (A1) component and the (A2) component may have an alkyl group (excluding cycloalkyl groups) from the viewpoint of more excellent transferability.

[0025] (A1) component's linear alkyl structure may have 10 or more, 11 or more, or 12 or more carbon atoms from the perspective of improving blocking resistance, and may have 24 or less, 23 or less, or 22 or less carbon atoms from the perspective of better transferability. (A1) component and (A2) component's linear alkyl structure may have 20 or less, 18 or less, 16 or less, or 14 or less carbon atoms, and may also have 14 or more, 16 or more, 18 or more, or 20 or more carbon atoms.

[0026] (A2) component's melting point may be -10°C or higher, -5°C or higher, or 0°C or higher from the perspective of improving blocking resistance, and may be 70°C or lower, 65°C or lower, or 60°C or lower from the perspective of better transferability. (A1) component and (A2) component's melting point may be 50°C or lower, 40°C or lower, 30°C or lower, 20°C or lower, 10°C or lower, or 5°C or lower, and may also be 10°C or higher, 20°C or higher, 30°C or higher, 40°C or higher, or 45°C or higher.

[0027] (A1) component and (A2) component may be (meth)acrylate compounds from the perspective of better transferability and blocking resistance.

[0028] (A1) component and (A2) component may have functional groups other than radical polymerizable groups, or may not have functional groups other than radical polymerizable groups. Examples of functional groups include hydroxy group, carboxyl group, amino group, etc.

[0029] Specific examples of (A1) component and (A2) component include lauryl acrylate (12 carbon atoms in the linear alkyl structure, melting point 0°C), stearyl acrylate (18 carbon atoms in the linear alkyl structure, melting point 30°C), stearyl methacrylate (18 carbon atoms in the linear alkyl structure, melting point 20°C), behenyl acrylate (22 carbon atoms in the linear alkyl structure, melting point 46°C), behenyl methacrylate (22 carbon atoms in the linear alkyl structure, melting point 47°C), etc.

[0030] The adhesive film for circuit connection according to another embodiment of the present invention may further contain a radically polymerizable compound that does not correspond to the (A1) component and the (A2) component as the (A) component (hereinafter, also referred to as "radically polymerizable compound A3" or "(A3) component").

[0031] The (A3) component may be a radically polymerizable compound that does not correspond to either the (A1) component or the (A2) component among the above-described radically polymerizable compounds. The (A3) component may contain a (poly)urethane (meth)acrylate compound from the viewpoint of achieving both cohesive force for reducing connection resistance and elongation for improving adhesive strength, and having more excellent transferability and adhesive properties.

[0032] The (A3) component may contain a (meth)acrylate compound represented by the following formula (1) (a (meth)acrylate compound having a phosphate ester structure). In this case, since the adhesive strength to the surface of an inorganic substance (such as a metal) is improved, it is suitable for adhesion between electrodes (for example, between circuit electrodes).

Chemical formula

[0033] The (meth)acrylate compound represented by formula (1) can be obtained, for example, by reacting phosphoric anhydride with 2-hydroxyethyl (meth)acrylate. Specific examples of the (meth)acrylate compound represented by formula (1) include mono(2-(meth)acryloyloxyethyl) acid phosphate, di(2-(meth)acryloyloxyethyl) acid phosphate, and the like.

[0034] The content of the (A1) component or the (A2) component in the (A) component may be 1% by mass or more, 3% by mass or more, or 5% by mass or more based on the total mass of the (A) component from the viewpoint of better transferability and blocking resistance. From the same viewpoint, it may be 50% by mass or less, 40% by mass or less, or 35% by mass or less. From these viewpoints, the content of the (A1) component or the (A2) component in the (A) component may be 1 to 50% by mass, 3 to 40% by mass, or 5 to 35% by mass. The content of the (A1) component or the (A2) component in the (A) component may be 7% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, or 25% by mass or more based on the total mass of the (A) component, and may also be 30% by mass or less, 25% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, or 7% by mass or less. When the adhesive film for circuit connection contains the (A1) component and the (A2) component as the (A) component, the total content of the (A1) component and the (A2) component in the (A) component may be within the above range.

[0035] The content of the (A3) component in the (A) component may be 99% by mass or less, 97% by mass or less, or 95% by mass or less based on the total mass of the (A) component from the viewpoint of better transferability and blocking resistance. From the same viewpoint, it may be 50% by mass or more, 60% by mass or more, or 65% by mass or more. The content of the (A3) component in the (A) component may be 93% by mass or less, 90% by mass or less, 85% by mass or less, 80% by mass or less, or 75% by mass or less based on the total mass of the (A) component, and may also be 70% by mass or more, 75% by mass or more, 80% by mass or more, 85% by mass or more, 90% by mass or more, or 93% by mass or more.

[0036] The content of the (poly)urethane (meth)acrylate compound may be, for example, 30% by mass or more, 40% by mass or more, or 50% by mass or more based on the total mass of the (A) component from the viewpoint of better transferability and adhesion characteristics, and may be 90% by mass or less, 85% by mass or less, or 80% by mass or less, and may be 30 to 90% by mass, 40 to 85% by mass, or 50 to 80% by mass.

[0037] The content of the (meth)acrylate compound represented by formula (1) is, from the viewpoint of further improving the adhesive force to the surface of the inorganic substance (such as metal) and further improving the adhesive strength between electrodes (for example, between circuit electrodes), for example, based on the total mass of component (A), it may be 0.1% by mass or more, 0.5% by mass or more, or 1% by mass or more, and may be 20% by mass or less, 10% by mass or less, or 5% by mass or less, and may be 0.1 to 20% by mass, 0.5 to 10% by mass, or 1 to 5% by mass.

[0038] (A) The content of the component is, from the viewpoint of easily obtaining the crosslinking density necessary for further reducing the connection resistance and further improving the connection reliability and further suppressing the flow of conductive particles, for example, based on the total amount of the components in the adhesive composition, it may be 5% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more, or 40% by mass or more. (A) The content of the component is, from the viewpoint of suppressing the curing shrinkage during polymerization and obtaining better transferability, for example, based on the total amount of the components other than the conductive particles in the adhesive composition, it may be 90% by mass or less, 80% by mass or less, 70% by mass or less, or 60% by mass. From these viewpoints, the content of component (A) may be, for example, based on the total amount of the components in the adhesive composition, 5 to 90% by mass, 10 to 80% by mass, 20 to 70% by mass, 30 to 60% by mass, or 40 to 60% by mass.

[0039] The content of component (A) is, from the viewpoints of easily obtaining the crosslinking density necessary for further reducing the connection resistance and further improving the connection reliability, and further suppressing the flow of conductive particles, for example, based on the total amount of components other than the conductive particles in the adhesive composition, it may be 5% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more, or 40% by mass or more. The content of component (A) is, from the viewpoint of suppressing the curing shrinkage during polymerization and obtaining better transferability, for example, based on the total amount of components other than the conductive particles in the adhesive composition, it may be 90% by mass or less, 80% by mass or less, 70% by mass or less, or 60% by mass. From these viewpoints, the content of component (A) is, for example, based on the total amount of components other than the conductive particles in the adhesive composition, 5 to 90% by mass, 10 to 80% by mass, 20 to 70% by mass, 30 to 60% by mass, or 40 to 60% by mass.

[0040] [Component (B): Polymerization initiator] Component (B) may be a photoinitiator (hereinafter also referred to as “component (B1)”), or may be a thermal polymerization initiator (hereinafter also referred to as “component (B2)”). Component (B) may contain component (B1) and component (B2).

[0041] Component (B1) is a photoinitiator (photo radical polymerization initiator, photo cationic polymerization initiator, or photo anionic polymerization initiator) that generates radicals, cations, or anions upon irradiation with light having a wavelength in the range of 150 to 750 nm, preferably light having a wavelength in the range of 254 to 405 nm, and more preferably light having a wavelength of 365 nm (for example, ultraviolet light). Component (B1) may be a photo radical polymerization initiator from the viewpoint of easier curing at low temperature for a short time. As component (B1), one kind of compound may be used alone, or a combination of a plurality of kinds of compounds may be used.

[0042] The photo radical polymerization initiator decomposes by light to generate free radicals. That is, the photo radical polymerization initiator is a compound that generates radicals by the application of external light energy. Examples of the photo radical polymerization initiator include photo polymerization initiators having structures such as an oxime ester structure, a bisimidazole structure, an acridine structure, an α-aminoalkylphenone structure, an aminobenzophenone structure, an N-phenylglycine structure, an acylphosphine oxide structure, a benzyldimethylketal structure, and an α-hydroxyalkylphenone structure.

[0043] (B) component, from the viewpoint of further improving the effect of suppressing the flow of conductive particles and the effect of suppressing peeling after transfer, a photo polymerization initiator having a structure represented by the following formula (I) may be used. The photo polymerization initiator may have a plurality of structures represented by the above formula (I).

Chemical formula

[0044] The structure represented by the above formula (I) may be an oxime ester structure, a bisimidazole structure or an acridine structure. That is, the adhesive composition may contain a photo polymerization initiator having at least one structure selected from the group consisting of an oxime ester structure, a bisimidazole structure and an acridine structure as the structure represented by the above formula (I). Among these, when a photo polymerization initiator having an oxime ester structure is used, the effect of suppressing the flow of conductive particles and the effect of suppressing peeling after transfer tend to be further improved.

[0045] Among the compounds having an oxime ester structure, when a compound having a structure represented by the following formula (VI) is used, the above effects tend to be obtained more remarkably.

Chemical formula

[0046] Specific examples of the compound having an oxime ester structure include 1-phenyl-1,2-butanedione-2-(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-o-benzoyloxime, 1,3-diphenylpropanetrione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-3-ethoxypropanetrione-2-(o-benzoyl)oxime, 1,2-octanedione, 1-[4-(phenylthio)phenyl]-, 2-(o-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(o-acetoxime), and the like.

[0047] Examples of the compound having a bisimidazole structure include 2,4,5-triarylimidazole dimers such as 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-di(m-methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-phenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer, 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer, 2,4-di(p-methoxyphenyl)-5-phenylimidazole dimer, 2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer.

[0048] Examples of the compound having an acridine structure include 9-phenylacridine, 1,7-bis(9,9'-acridinyl)heptane, and the like.

[0049] The content of the photopolymerization initiator having the structure represented by the above formula (I) may be, from the viewpoint of further improving the flow suppression effect of the conductive particles, for example, 0.1% by mass or more, 0.2% by mass or more, 0.3% by mass or more, or 0.4% by mass or more based on the total amount of the components in the adhesive composition. The content of the photopolymerization initiator having the structure represented by the above formula (I) may be, from the viewpoint of further improving the peeling suppression effect after transfer, for example, 1% by mass or less, 0.7% by mass or less, or 0.5% by mass or less based on the total amount of the components in the adhesive composition. From these viewpoints, the content of the photopolymerization initiator having the structure represented by the above formula (I) may be, for example, 0.1 to 1% by mass, 0.2 to 1% by mass, 0.3 to 0.7% by mass, or 0.4 to 0.5% by mass based on the total amount of the components in the adhesive composition.

[0050] The content of the photopolymerization initiator having the structure represented by the above formula (I) may be, from the viewpoint of further improving the flow suppression effect of the conductive particles, for example, 0.1% by mass or more, 0.3% by mass or more, 0.4% by mass or more, 0.5% by mass or more, or 0.55% by mass or more based on the total amount of the components other than the conductive particles in the adhesive composition. The content of the photopolymerization initiator having the structure represented by the above formula (I) may be, from the viewpoint of further improving the peeling suppression effect after transfer, for example, 1.2% by mass or less, 0.9% by mass or less, or 0.6% by mass or less based on the total amount of the components other than the conductive particles in the adhesive composition. From these viewpoints, the content of the photopolymerization initiator having the structure represented by the above formula (I) may be, for example, 0.1 to 1.2% by mass, 0.3 to 1.2% by mass, 0.4 to 0.9% by mass, or 0.5 to 0.6% by mass based on the total amount of the components other than the conductive particles in the adhesive composition.

[0051] The component (B2) may be a thermal polymerization initiator (thermal radical polymerization initiator, thermal cationic polymerization initiator, or thermal anionic polymerization initiator) that generates radicals, cations, or anions by heat. The component (B2) may be a thermal radical polymerization initiator from the viewpoint of further improving the effect of reducing the connection resistance and being more excellent in connection reliability. As the component (B2), one kind of compound may be used alone, or a plurality of kinds of compounds may be used in combination.

[0052] A thermal radical polymerization initiator decomposes by heat to generate free radicals. That is, a thermal radical polymerization initiator is a compound that generates radicals by the application of external thermal energy. As the thermal radical polymerization initiator, it can be arbitrarily selected from conventionally known organic peroxides and azo compounds. The thermal radical polymerization initiator may be an organic peroxide from the viewpoint of further improving the flow suppression effect of conductive particles and the peeling suppression effect after transfer. From the viewpoint of better stability, reactivity and compatibility, it may be an organic peroxide having a half-life temperature of 90 to 175 °C for 1 minute and a weight average molecular weight of 180 to 1000. When the half-life temperature of the organic peroxide is in the above range, there is a tendency to be further excellent in storage stability, and since a sufficiently high radical polymerizability can be obtained, it is also possible to cure in a short time.

[0053] (B2) Specific examples of the components include organic peroxides such as 1,1,3,3-tetramethylbutyl peroxyneodecanoate, di(4-t-butylcyclohexyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, cumyl peroxyneodecanoate, dilauroyl peroxide, 1-cyclohexyl-1-methylethyl peroxyneodecanoate, t-hexyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, t-hexyl peroxy-2-ethylhexanoate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxyneoheptanoate, t-amyl peroxy-2-ethylhexanoate, di-t-butyl peroxyhexahydroterephthalate, t-amyl peroxy-3,5,5-trimethylhexanoate, 3-hydroxy-1,1-dimethylbutyl peroxyneodecanoate, t-amyl peroxyneodecanoate, di(3-methylbenzoyl) peroxide, dibenzoyl peroxide, di(4-methylbenzoyl) peroxide, t-hexyl peroxyisopropyl monocarbonate, t-butyl peroxymaleic acid, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxylaurate, 2,5-dimethyl-2,5-di(3-methylbenzoylperoxy)hexane, t-butyl peroxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butyl peroxybenzoate, dibutyl peroxytriethyl adipate, t-amyl peroxy normal octoate, t-amyl peroxyisononanoate, t-amyl peroxybenzoate, etc.;Examples of the azo compound include 2,2'-azobis(2,4-dimethylvaleronitrile), 1,1'-azobis(1-acetoxy-1-phenylethane), 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 4,4'-azobis(4-cyanovaleric acid), 1,1'-azobis(1-cyclohexanecarbonitrile), and the like.

[0054] (B2) component content, from the perspective of excellent rapid curability, and from the perspective of further improving the flow suppression effect of conductive particles and the peeling suppression effect after transfer, may be 0.5% by mass or more, 1% by mass or more, 1.5% by mass or more, or 2% by mass or more based on the total amount of components in the adhesive composition. From the perspective of pot life, the content of (B2) component may be, for example, 5% by mass or less, 3.5% by mass or less, or 2.5% by mass or less based on the total amount of components in the adhesive composition. From these perspectives, the content of (B2) component may be, for example, 0.5 - 5% by mass, 1 - 5% by mass, 1.5 - 3.5% by mass, or 2 - 2.5% by mass based on the total amount of components in the adhesive composition.

[0055] (B2) component content, from the perspective of excellent rapid curability, and from the perspective of further improving the flow suppression effect of conductive particles and the peeling suppression effect after transfer, may be 0.5% by mass or more, 1.5% by mass or more, or 2.5% by mass or more based on the total amount of components other than conductive particles in the adhesive composition. From the perspective of pot life, the content of (B2) component may be, for example, 20% by mass or less, 10% by mass or less, or 5% by mass or less based on the total amount of components other than conductive particles in the adhesive composition. From these perspectives, the content of (B2) component may be, for example, 0.5 - 20% by mass, 1.5 - 10% by mass, or 2 - 5% by mass based on the total amount of components other than conductive particles in the adhesive composition.

[0056] The content of component (B) (the total content of component (B1) and component (B2)) may be, for example, 1% by mass or more, 1.5% by mass or more, 2% by mass or more, or 2.5% by mass or more, based on the total amount of components in the adhesive composition, from the viewpoint of further improving the flow suppression effect of the conductive particles. The content of component (B) may be, for example, 20% by mass or less, 10% by mass or less, 5% by mass or less, or 3% by mass or less, based on the total amount of components in the adhesive composition, from the viewpoint of further improving the peeling suppression effect after transfer. From these viewpoints, the content of component (B) may be, for example, 1 to 20% by mass, 1 to 10% by mass, 1.5 to 5% by mass, or 2.5 to 3% by mass, based on the total amount of components in the adhesive composition.

[0057] The content of component (B) (the total content of component (B1) and component (B2)) may be, for example, 1% by mass or more, 2% by mass or more, 2.5% by mass or more, or 3% by mass or more, based on the total amount of components other than the conductive particles in the adhesive composition, from the viewpoint of further improving the flow suppression effect of the conductive particles. The content of component (B) may be, for example, 25% by mass or less, 15% by mass or less, 10% by mass or less, or 5% by mass or less, based on the total amount of components other than the conductive particles in the adhesive composition, from the viewpoint of further improving the peeling suppression effect after transfer. From these viewpoints, the content of component (B) may be, for example, 1 to 25% by mass, 2 to 15% by mass, 2.5 to 10% by mass, or 3 to 5% by mass, based on the total amount of components other than the conductive particles in the adhesive composition.

[0058] [(C) Component: Conductive Particles] (C) component is not particularly limited as long as it is conductive particles, and may be metal particles composed of metals such as Au, Ag, Ni, Cu, solder, etc., conductive carbon particles composed of conductive carbon, and the like. (C) component may be coated conductive particles including a core containing non-conductive glass, ceramic, plastic (such as polystyrene), etc., and a coating layer containing the above metal or conductive carbon and covering the core. Among these, when using metal particles formed of a heat-meltable metal or coated conductive particles including a core containing plastic and a coating layer containing a metal or conductive carbon and covering the core, it becomes easy to deform the cured product of the adhesive composition by heating or pressurization. Therefore, when electrically connecting electrodes to each other, the contact area between the electrode and the (C) component can be increased, and the conductivity between the electrodes can be further improved.

[0059] (C) component may be insulating coated conductive particles including the above metal particles, conductive carbon particles, or coated conductive particles, and an insulating material such as resin, and having an insulating layer covering the surface of the particles. When the (C) component is insulating coated conductive particles, even when the content of the (C) component is large, since the surface of the particles is coated with resin, the occurrence of short circuit due to contact between the (C) components can be suppressed, and the insulation between adjacent electrode circuits can also be improved. The (C) component is used alone or in combination of two or more of the various conductive particles described above.

[0060] The maximum particle size of the (C) component needs to be smaller than the minimum distance between electrodes (the shortest distance between adjacent electrodes). The maximum particle size of the (C) component may be 1.0 μm or more, may be 2.0 μm or more, and may be 2.5 μm or more from the viewpoint of excellent dispersibility and conductivity. From the perspective of excellent dispersibility and conductivity, the maximum particle size of the (C) component may be 50 μm or less, may be 30 μm or less, and may be 20 μm or less. From these perspectives, the maximum particle size of the (C) component may be 1.0 to 50 μm, may be 2.0 to 30 μm, and may be 2.5 to 20 μm. In this specification, for any 300 pieces (pcs) of conductive particles, the particle size is measured by observation using a scanning electron microscope (SEM), and the largest value obtained is taken as the maximum particle size of the (C) component. When the (C) component is not spherical, such as having protrusions, the particle size of the (C) component is taken as the diameter of the circle circumscribing the conductive particles in the SEM image.

[0061] From the perspective of excellent dispersibility and conductivity, the average particle size of the (C) component may be 1.0 μm or more, may be 2.0 μm or more, and may be 2.5 μm or more. From the perspective of excellent dispersibility and conductivity, the average particle size of the (C) component may be 50 μm or less, may be 30 μm or less, and may be 20 μm or less. From these perspectives, the average particle size of the (C) component may be 1.0 to 50 μm, may be 2.0 to 30 μm, and may be 2.5 to 20 μm. In this specification, for any 300 pieces (pcs) of conductive particles, the particle size is measured by observation using a scanning electron microscope (SEM), and the average value of the obtained particle sizes is taken as the average particle size.

[0062] In the first adhesive layer 2, the (C) component may be uniformly dispersed. The particle density of the (C) component in the first adhesive layer 2 may be 100 pcs / mm 2 or more, may be 1000 pcs / mm 2 or more, and may be 2000 pcs / mm 2 or more. From the perspective of improving the insulation between adjacent electrodes, the particle density of the (C) component in the first adhesive layer 2 may be 100000 pcs / mm 2 or less, may be 50000 pcs / mm 2 or less, and may be 10000 pcs / mm 2 or less.

[0063] The content of component (C) may be, from the viewpoint of further improving conductivity, for example, 5% by mass or more, 15% by mass or more, or 20% by mass or more based on the total mass of the adhesive composition. The content of component (C) may be, from the viewpoint of being likely to suppress short circuits, for example, 50% by mass or less, 40% by mass or less, or 30% by mass or less based on the total mass of the adhesive composition. From these viewpoints, the content of component (C) may be, for example, 5 to 50% by mass, 10 to 40% by mass, or 20 to 30% by mass based on the total mass of the adhesive composition. Note that the content of component (C) based on the total mass of the cured product of the adhesive composition may be the same as the above range, and the content of component (C) based on the total mass of the first adhesive layer may also be the same as the above range.

[0064] The content of component (C) may be, from the viewpoint of further improving conductivity, 0.1% by volume or more, 1% by volume or more, or 5% by volume or more based on the total volume of the cured product of the adhesive composition. The content of component (C) may be, from the viewpoint of being likely to suppress short circuits, 50% by volume or less, 30% by volume or less, or 20% by volume or less based on the total volume of the cured product of the adhesive composition. Note that the content of component (C) based on the total volume of the adhesive composition may be the same as the above range, and the content of component (C) based on the total volume of the first adhesive layer may also be the same as the above range.

[0065] [Other Components] The adhesive composition may further contain other components other than the above-described components. Examples of the other components include thermoplastic resins, coupling agents, fillers, thermosetting resins, and the like. These components may also be contained in the first adhesive layer 2.

[0066] Examples of the thermoplastic resin include phenoxy resin, polyester resin, polyamide resin, polyurethane resin, polyester urethane resin, acrylic rubber, and the like. When the adhesive composition contains a thermoplastic resin, the first adhesive layer can be easily formed. Further, when the adhesive composition contains a thermoplastic resin, the stress of the first adhesive layer generated during the curing of the adhesive composition can be relaxed. Further, when the thermoplastic resin has a functional group such as a hydroxyl group, the adhesiveness of the first adhesive layer is likely to be improved. From such a viewpoint, phenoxy resin may be used as the thermoplastic resin. The content of the thermoplastic resin may be, for example, 5% by mass or more, 80% by mass or less, or 5 to 80% by mass based on the total amount of components other than the conductive particles in the adhesive composition.

[0067] Examples of the coupling agent include silane coupling agents having an organic functional group such as a (meth)acryloyl group, a mercapto group, an amino group, an imidazole group, and an epoxy group, silane compounds such as tetraalkoxysilane, tetraalkoxy titanate derivatives, and polydialkyl titanate derivatives. When the adhesive composition contains a coupling agent, the adhesiveness can be further improved. The content of the coupling agent may be, for example, 0.1% by mass or more and 20% by mass or less based on the total amount of components other than the conductive particles in the adhesive composition. In the present specification, a silane coupling agent having a polymerizable group such as a (meth)acryloyl group is not included in the polymerizable compound.

[0068] Examples of the filler include non-conductive fillers (for example, non-conductive particles). When the adhesive composition contains a filler, further improvement in connection reliability can be expected. The filler may be either an inorganic filler or an organic filler. Examples of the inorganic filler include metal oxide fine particles such as silica fine particles, alumina fine particles, silica-alumina fine particles, titania fine particles, and zirconia fine particles; and inorganic fine particles such as nitride fine particles. Examples of the organic filler include organic fine particles such as silicone fine particles, methacrylate-butadiene-styrene fine particles, acrylic-silicone fine particles, polyamide fine particles, and polyimide fine particles. These fine particles may have a uniform structure or a core-shell type structure. The maximum diameter of the filler may be less than the minimum particle size of the conductive particles 4. The content of the filler may be, for example, 1% by volume or more, 30% by volume or less, or 1 to 30% by volume based on the total volume of the adhesive composition.

[0069] Examples of the thermosetting resin include silicone resin, epoxy resin, phenol resin, cyanate resin, melamine resin, urea resin, thermosetting polyimide resin, and unsaturated polyester resin. The content of the thermosetting resin may be, for example, 0.1% by mass or more and 20% by mass or less based on the total amount of the components other than the conductive particles in the adhesive composition.

[0070] The adhesive composition may contain other additives such as a softening agent, a promoter, an anti-degradant, a colorant, a flame retardant, and a thixotropic agent. The content of these additives may be, for example, 0.1 to 10% by mass based on the total amount of the components other than the conductive particles in the adhesive composition. These additives may be contained in the first adhesive layer 2.

[0071] The thickness d1 of the first adhesive layer 2 may be appropriately set according to, for example, the height of the electrodes of the circuit members to be bonded. The thickness d1 of the first adhesive layer 2 may be, for example, 0.5 μm or more and 20 μm or less. When a part of the conductive particles 4 is exposed from the surface of the first adhesive layer 2 (for example, protrudes toward the second adhesive layer 3 side), the distance from the surface 2a of the first adhesive layer 2 on the side opposite to the second adhesive layer 3 side to the boundary S between the first adhesive layer 2 and the second adhesive layer 3 located at the separation portion between the adjacent conductive particles 4, 4 (the distance indicated by d1 in FIG. 1) is the thickness of the first adhesive layer 2, and the exposed portion of the conductive particles 4 is not included in the thickness of the first adhesive layer 2. The length of the exposed portion of the conductive particles 4 may be, for example, 0.1 μm or more, 20 μm or less, or 0.1 to 20 μm.

[0072] The thickness of the adhesive layer can be measured by the following method. First, sandwich the adhesive film between two pieces of glass (thickness: about 1 mm). Next, cast with a resin composition composed of 100 g of bisphenol A type epoxy resin (trade name: JER811, manufactured by Mitsubishi Chemical Corporation) and 10 g of a curing agent (trade name: Epomount curing agent, manufactured by Refine Tech Co., Ltd.). Then, perform cross-section polishing using a polishing machine, and measure the thickness of each adhesive layer using a scanning electron microscope (SEM, trade name: SE-8020, manufactured by Hitachi High-Technologies Corporation).

[0073] (Second Adhesive Layer) The second adhesive layer 3 is composed of a cured product of an adhesive composition (second adhesive composition). The adhesive composition contains, for example, the above-described components (A) and (B). The adhesive composition may contain, as other components, for example, a thermoplastic resin, a coupling agent, a filler, a softening agent, an accelerator, an anti-degradant, a coloring agent, a flame retardant, and a thixotropic agent. The details of the other components are the same as those of the other components in the first adhesive layer 2.

[0074] The second adhesive layer 3 (thermosetting composition) may not contain a photopolymerization initiator and may not contain conductive particles. The content of the photopolymerization initiator in the second adhesive layer 3 may be, for example, 1% by mass or less or 0% by mass based on the total mass of the second adhesive layer 3. The content of the conductive particles 4 in the second adhesive layer 3 may be, for example, 1% by mass or less or 0% by mass based on the total mass of the second adhesive layer.

[0075] The thickness d2 of the second adhesive layer 3 may be appropriately set according to the height of the electrode of the circuit member to be adhered, etc. The thickness d2 of the second adhesive layer 3 may be 5 μm or more, may be 200 μm or less, and may be 5 to 200 μm from the viewpoint of being able to sufficiently fill the space between the electrodes and seal the electrodes to obtain better connection reliability. When a part of the conductive particles 4 is exposed from the surface of the first adhesive layer 2 (for example, protrudes toward the second adhesive layer 3 side), from the surface 3a on the side opposite to the first adhesive layer 2 side in the second adhesive layer 3, to the boundary S between the first adhesive layer 2 and the second adhesive layer 3 located at the separation part between the adjacent conductive particles 4,4 (the distance indicated by d2 in FIG. 1) is the thickness of the second adhesive layer 3.

[0076] The ratio of the thickness d1 of the first adhesive layer 2 to the thickness d2 of the second adhesive layer 3 (thickness d1 of the first adhesive layer 2 / thickness d2 of the second adhesive layer 3) may be 1 or more, may be 100 or less, and may be 1 to 100 from the viewpoint of being able to sufficiently fill the space between the electrodes and seal the electrodes to obtain better reliability.

[0077] The thickness of the adhesive film 1 (the total thickness of all the layers constituting the adhesive film 1. In FIG. 1, it is the total of the thickness d1 of the first adhesive layer 2 and the thickness d2 of the second adhesive layer 3.) may be, for example, 5 μm or more, may be 200 μm or less, and may be 5 to 200 μm.

[0078] In the adhesive film 1, the conductive particles 4 are dispersed in the first adhesive layer 2. Therefore, the adhesive film 1 is an anisotropic conductive adhesive film having anisotropic conductivity. The adhesive film 1 is interposed between a first circuit member having a first electrode and a second circuit member having a second electrode, and the first circuit member and the second circuit member are thermocompression bonded to electrically connect the first electrode and the second electrode to each other.

[0079] According to the adhesive film 1, it has sufficient transferability, and the transfer of the adhesive film can be performed in a short time. Further, according to the adhesive film 1, there is a tendency to suppress peeling at the interface between the circuit member and the circuit connection member that occurs when the circuit connection structure is used in a high temperature and high humidity environment.

[0080] As described above, the adhesive film for circuit connection of the present embodiment has been described, but the present invention is not limited to the above embodiment.

[0081] For example, the adhesive film for circuit connection may be composed of two layers, a first adhesive layer and a second adhesive layer, and may be composed of three or more layers including layers other than the first adhesive layer and the second adhesive layer (for example, a third adhesive layer). The third adhesive layer may be a layer having the same composition as that described above for the first adhesive layer or the second adhesive layer, and may be a layer having the same thickness as that described above for the first adhesive layer or the second adhesive layer.

[0082] Further, the adhesive film for circuit connection of the above embodiment is an anisotropic conductive adhesive film having anisotropic conductivity, but the adhesive film for circuit connection may be a conductive adhesive film having no anisotropic conductivity.

[0083] <Manufacturing method of adhesive film for circuit connection> The manufacturing method of the adhesive film 1 for circuit connection according to this embodiment includes, for example, a preparation step (first preparation step) of preparing the above-described first adhesive layer 2, and a lamination step of laminating the above-described second adhesive layer 3 on the first adhesive layer 2. The manufacturing method of the adhesive film 1 for circuit connection may further include a preparation step (second preparation step) of preparing the second adhesive layer 3. Note that the order of performing the first preparation step and the second preparation step is not limited, and the first preparation step may be performed first, or the second preparation step may be performed first.

[0084] In the first preparation step, for example, the first adhesive layer 2 is prepared by forming the first adhesive layer 2 on a base material to obtain a first adhesive film. Specifically, first, the component (A), the component (B), and the component (C), and other components added as necessary are added into a solvent (organic solvent), and the components are dissolved or dispersed by stirring, mixing, kneading, etc. to prepare a varnish composition (varnish-like adhesive composition). Then, the varnish composition is applied onto the base material subjected to a release treatment using a knife coater, a roll coater, an applicator, a comma coater, a die coater, etc., and then the solvent is volatilized by heating to form a layer made of the adhesive composition on the base material. Subsequently, the adhesive composition is cured (photo-cured) by irradiating light onto the layer made of the adhesive composition, and the first adhesive layer 2 is formed on the base material (curing step). Thereby, the first adhesive film is obtained.

[0085] As the solvent used for preparing the varnish composition, a solvent having the property of being able to uniformly dissolve or disperse each component may be used. Examples of such solvents include toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, butyl acetate, etc. These solvents can be used alone or in combination of two or more. The stirring, mixing, and kneading during the preparation of the varnish composition can be performed using, for example, a stirrer, a kneader, a three-roll mill, a ball mill, a bead mill, or a homodisper.

[0086] The base material is not particularly limited as long as it has heat resistance capable of withstanding the heating conditions when the solvent is volatilized. For example, a base material (such as a film) made of stretched polypropylene (OPP), polyethylene terephthalate (PET), polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, polyimide, cellulose, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, synthetic rubber-based, liquid crystal polymer, etc. can be used.

[0087] The heating conditions when the solvent is volatilized from the varnish composition applied to the base material may be conditions under which the solvent is sufficiently volatilized. The heating conditions may be, for example, 40°C or higher and 120°C or lower for 0.1 minute or longer and 10 minutes or shorter.

[0088] A part of the solvent may remain without being removed in the layer made of the adhesive composition. The solvent content in the layer made of the adhesive composition may be, for example, 10% by mass or less based on the total mass of the layer made of the adhesive composition.

[0089] For the irradiation of light in the curing process, irradiation light (such as ultraviolet light) in the wavelength range of 150 to 750 nm may be used. The light irradiation can be carried out, for example, using a low-pressure mercury lamp, medium-pressure mercury lamp, high-pressure mercury lamp, ultra-high-pressure mercury lamp, xenon lamp, metal halide lamp, LED light source, etc. The light irradiation amount is not particularly limited. For example, in terms of the integrated light amount of light with a wavelength of 365 nm, it may be 100 mJ / cm 2 or more, and may be 200 mJ / cm 2 or more, and may be 300 mJ / cm 2 or more. The light irradiation amount may be, for example, in terms of the integrated light amount of light with a wavelength of 365 nm, 10000 mJ / cm 2 or less, and may be 5000 mJ / cm 2 or less, and may be 3000 mJ / cm 2 or less.

[0090] In the second preparation step, in the same manner as in the first preparation step, the second adhesive layer 3 is prepared by forming the second adhesive layer 3 on the base material to obtain the second adhesive film.

[0091] A part of the solvent may remain without being removed in the second adhesive layer 3. The solvent content in the second adhesive layer 3 may be, for example, 10% by mass or less based on the total mass of the second adhesive layer 3.

[0092] In the lamination step, the second adhesive layer 3 may be laminated on the first adhesive layer 2 by bonding the first adhesive film and the second adhesive film together, or the varnish composition used to form the second adhesive layer 3 may be applied on the first adhesive layer 2 and the solvent may be volatilized to laminate the second adhesive layer 3 on the first adhesive layer 2.

[0093] Examples of the method of bonding the first adhesive film and the second adhesive film include methods such as hot pressing, roll lamination, and vacuum lamination. The lamination may be performed, for example, under temperature conditions of 0 to 80°C.

[0094] <Circuit Connection Structure and Its Manufacturing Method> Hereinafter, a circuit connection structure using the above-described circuit connection adhesive film 1 as a circuit connection material and its manufacturing method will be described.

[0095] FIG. 2 is a schematic cross-sectional view showing a circuit connection structure according to an embodiment. As shown in FIG. 2, the circuit connection structure 10 includes a first circuit member 13 having a first circuit board 11 and a first electrode 12 formed on a main surface 11a of the first circuit board 11, a second circuit member 16 having a second circuit board 14 and a second electrode 15 formed on a main surface 14a of the second circuit board 14, and a circuit connection portion 17 disposed between the first circuit member 13 and the second circuit member 16 and electrically connecting the first electrode 12 and the second electrode 15 to each other.

[0096] The first circuit member 13 and the second circuit member 16 may be the same as or different from each other. The first circuit member 13 and the second circuit member 16 may be a glass substrate or a plastic substrate on which electrodes are formed, a printed wiring board, a ceramic wiring board, a flexible wiring board, a semiconductor silicon IC chip, or the like. The first circuit board 11 and the second circuit board 14 may be formed of inorganic substances such as semiconductors, glass, and ceramics, organic substances such as polyimide and polycarbonate, composites such as glass / epoxy, and the like. The first electrode 12 and the second electrode 15 may be formed of gold, silver, tin, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper, aluminum, molybdenum, titanium, indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), or the like. The first electrode 12 and the second electrode 15 may be circuit electrodes or bump electrodes. At least one of the first electrode 12 and the second electrode 15 may be a bump electrode. In FIG. 2, the second electrode 15 is a bump electrode.

[0097] The circuit connection portion 17 is composed of a cured product of the adhesive film 1 described above. The circuit connection portion 17 is located, for example, on the first circuit member 13 side in the direction in which the first circuit member 13 and the second circuit member 16 face each other (hereinafter referred to as the "opposing direction"), and is composed of a first region 18 made of a cured product of a component other than the conductive particles 4 of the above-described adhesive composition, and a second region 19 made of a cured product of the above-described thermosetting composition, which is located on the second circuit member 16 side in the opposing direction, and has conductive particles 4 that are interposed between at least the first electrode 12 and the second electrode 15 and electrically connect the first electrode 12 and the second electrode 15 to each other. The circuit connection portion does not necessarily have two regions such as the first region 18 and the second region 19, and may be composed of, for example, a cured product in which the cured product of the component other than the conductive particles 4 of the above-described adhesive composition and the cured product of the above-described thermosetting composition are mixed.

[0098] The manufacturing method of the circuit connection structure 10 described above includes, for example, a step of preparing a first circuit member 13 having a first electrode 12, a second circuit member 16 having a second electrode 15, and an adhesive film with a substrate (circuit connection adhesive film) 1 provided on the substrate; a step of transferring (laminating) the adhesive film 1 from the substrate onto the surface of the first circuit member 13 where the first electrode 12 is formed; and a step of arranging the first circuit member 13, the adhesive film 1, and the second circuit member 16 in this order so that the first electrode 12 and the second electrode 15 face each other, and then thermocompression bonding the first circuit member 13 and the second circuit member 16 to electrically connect the first electrode 12 and the second electrode 15 to each other.

[0099] Specifically, first, a first circuit member 13 having a first circuit board 11 and a first electrode 12 formed on the main surface 11a of the first circuit board 11, a second circuit member 16 having a second circuit board 14 and a second electrode 15 formed on the main surface 14a of the second circuit board 14, and an adhesive film with a substrate provided with the adhesive film 1 on the substrate are prepared. The substrate included in the adhesive film with a substrate may be the substrate used in the manufacture of the above-described adhesive film.

[0100] Next, the adhesive film 1 is transferred (laminated) from the substrate onto the surface of the first circuit member 13 where the first electrode 12 is formed. Specifically, for example, the adhesive film 1 is laminated on the first circuit member 13 such that the first adhesive layer 2 side faces the mounting surface 11a of the first circuit member 13.

[0101] The lamination method is not particularly limited, and a roll laminator, a diaphragm laminator, a vacuum roll laminator, or a vacuum diaphragm laminator can be employed. After temporary lamination, pressure bonding may be performed using a thermocompression bonding device.

[0102] The lamination conditions may be appropriately set according to the type of laminator used, the base material, the first circuit member 13, the second circuit member 16, and the like. The temperature during lamination (crimping temperature) may be, for example, 50 to 90 °C. The pressure during lamination (crimping pressure) may be, for example, 0.5 to 1.5 MPa. The lamination time (crimping time) may be, for example, 0.5 to 1.5 seconds.

[0103] Next, as shown in Fig. 3(a), the second circuit member 16 is disposed on the first circuit member 13 laminated with the adhesive film 1 such that the first electrode 12 and the second electrode 15 face each other.

[0104] Then, as shown in Fig. 3(b), while heating the first circuit member 13, the adhesive film 1, and the second circuit member 16, the first circuit member 13 and the second circuit member 16 are pressed in the thickness direction to thermally bond the first circuit member 13 and the second circuit member 16 to each other. At this time, as indicated by the arrow in Fig. 3(b), since the second adhesive layer 3 is composed of a flowable uncured thermosetting composition, it flows so as to fill the gap between the second electrodes 15, 15 and cures by the above heating. As a result, the first electrode 12 and the second electrode 15 are electrically connected to each other via the conductive particles 4, and the first circuit member 13 and the second circuit member 16 are adhered to each other, thereby obtaining the circuit connection structure 10 shown in Fig. 2. In the manufacturing method of the circuit connection structure 10 of the present embodiment, since the first adhesive layer 2 is a pre-cured layer, the conductive particles 4 hardly flow during the above thermal crimping, and the conductive particles are efficiently captured between the opposing electrodes, so that the connection resistance between the opposing electrodes 12 and 15 is reduced. Therefore, a circuit connection structure excellent in connection reliability can be obtained.

[0105] The temperature and time during thermal crimping may be any temperature that can sufficiently cure the adhesive film 1 and bond the first circuit member 13 and the second circuit member 16. The thermal crimping temperature may be, for example, 150 to 200 °C. The thermal crimping time may be, for example, 4 to 7 seconds.

Example

[0106] Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the examples.

[0107] <Synthesis of Polyurethane Acrylate (UA1)> Into a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser having a calcium chloride drying tube, and a nitrogen gas introduction tube, 2500 parts by mass (2.50 mol) of poly(1,6-hexanediol carbonate) (trade name: Duranol T5652, manufactured by Asahi Kasei Chemicals Corporation, number average molecular weight 1000) and 666 parts by mass (3.00 mol) of isophorone diisocyanate (manufactured by Sigma-Aldrich) were uniformly added dropwise over 3 hours. Next, after sufficiently introducing nitrogen gas into the reaction vessel, the inside of the reaction vessel was heated to 70 - 75 °C for reaction. Next, 0.53 parts by mass (4.3 mmol) of hydroquinone monomethyl ether (manufactured by Sigma-Aldrich) and 5.53 parts by mass (8.8 mmol) of dibutyltin dilaurate (manufactured by Sigma-Aldrich) were added to the reaction vessel, and then 238 parts by mass (2.05 mol) of 2-hydroxyethyl acrylate (manufactured by Sigma-Aldrich) was added, and the reaction was carried out at 70 °C for 6 hours under an air atmosphere. Thereby, polyurethane acrylate (UA1) was obtained. The weight average molecular weight of polyurethane acrylate (UA1) was 15000. The weight average molecular weight was measured using a calibration curve with standard polystyrene from a gel permeation chromatograph (GPC) according to the following conditions. (Measurement Conditions) Apparatus: GPC-8020 manufactured by Tosoh Corporation Detector: RI-8020 manufactured by Tosoh Corporation Column: Gelpack GLA160S + GLA150S manufactured by Hitachi Chemical Co., Ltd. Sample concentration: 120 mg / 3 mL Solvent: Tetrahydrofuran Injection volume: 60 μL Pressure: 2.94×10 6 Pa (30 kgf / cm 2 ) Flow rate: 1.00 mL / min

[0108] <Production of Conductive Particles> A layer made of nickel was formed on the surface of the polystyrene particles so that the thickness of the layer was 0.2 μm. In this way, conductive particles with an average particle size of 4 μm, a maximum particle size of 4.5 μm, and a specific gravity of 2.5 were obtained.

[0109] <Method for Preparing Polyester Urethane Resin> 48 parts by mass of isophthalic acid and 37 parts by mass of neopentyl glycol were charged into a stainless steel autoclave with a heater equipped with a stirrer, a thermometer, a condenser, a vacuum generator, and a nitrogen gas inlet tube. Further, 0.02 parts by mass of tetrabutoxytitanate as a catalyst was charged. Then, the temperature was raised to 220 °C under a nitrogen stream and stirred for 8 hours as it was. Thereafter, the pressure was reduced to atmospheric pressure (760 mmHg), cooled to room temperature, and then the white precipitate was taken out, washed with water, and dried in vacuo to obtain a polyester polyol.

[0110] After sufficiently drying the polyester polyol obtained by the reaction of the above-described dicarboxylic acid and diol, it was dissolved in MEK and charged into a four-necked flask equipped with a stirrer, a dropping funnel, a reflux condenser, and a nitrogen gas inlet tube. Further, dibutyltin laurate was added as a catalyst in an amount of 0.05 parts by mass per 100 parts by mass of the polyester polyol, and 4,4'-diphenylmethane diisocyanate dissolved in MEK was added in an amount of 50 parts by mass per 100 parts by mass of the polyester polyol through the dropping funnel and stirred at 80 °C for 4 hours to obtain the target polyester urethane resin.

[0111] <Preparation of First Adhesive Composition and Second Adhesive Composition> Each component was mixed in the blending amounts (unit: parts by mass) shown in Table 1 and Table 2 to prepare a first adhesive composition for forming a first adhesive layer and a second adhesive composition for forming a second adhesive layer. The details of each component in Table 1 and Table 2 are as follows, and the blending amounts of each component in the table represent the blending amounts of the non-volatile components. (Radical Polymerizable Compound) A1: Stearyl acrylate (trade name: Brenmer SA, manufactured by NOF Corporation, straight-chain alkyl structure with 18 carbon atoms, melting point 30 °C) A2: Behenyl acrylate (trade name: Brenmer VA, manufactured by NOF Corporation, straight-chain alkyl structure with 22 carbon atoms, melting point 46 °C) A3: Bisphenol-based epoxy acrylate (trade name: Lipoxy VR-90, manufactured by Showa Highpolymer Co., Ltd., melting point 43 - 48 °C) A4: Dicyclopentadiene type diacrylate (trade name: DCP-A, manufactured by Toagosei Co., Ltd.) A5: Polyurethane acrylate (UA1) synthesized as described above A6: 2-Methacryloyloxyethyl acid phosphate (trade name: Light Ester P-2M, manufactured by Kyoeisha Chemical Co., Ltd.) (Photoinitiator) B1: 1,2-Octanedione, 1-[4-(phenylthio)phenyl]-, 2-(O-benzoyloxime) (trade name: Irgacure® OXE01, manufactured by BASF) (Thermal initiator) C1: Benzoyl peroxide (trade name: Nipex BMT-K40, manufactured by NOF Corporation) (Conductive particles) D1: Conductive particles prepared as described above (Thermoplastic resin) E1: Polyester urethane resin synthesized above (Coupling agent) F1: 3-Methacryloxypropyltrimethoxysilane (trade name: KBM503, manufactured by Shin-Etsu Chemical Co., Ltd.) (Filler) G1: Silica fine particles (trade name: R104, manufactured by Nippon Aerosil Co., Ltd., average particle size (primary particle size): 12 nm) (Solvent) H1: Methyl ethyl ketone

[0112]

Table 1

[0113]

Table 2

[0114] <Fabrication of Adhesive Film for Circuit Connection> The first adhesive composition was applied onto a 50-μm thick PET film using a coating apparatus. Subsequently, hot air drying was carried out at 70 °C for 3 minutes to form a layer with a thickness (thickness after drying) of 4 μm on the PET film. The thickness was measured using a contact thickness gauge. Then, the layer on the PET film was irradiated with light using a metal halide lamp so that the integrated light quantity became 1500 mJ / cm 2 and the radically polymerizable compound was polymerized. Thereby, the layer on the PET film was cured to form the first adhesive layer. Through the above operations, a first adhesive film having a first adhesive layer (thickness of the region where conductive particles are present: 4 μm) on the PET film was obtained.

[0115] The second adhesive composition was applied onto a 50-μm thick PET film using a coating apparatus. Subsequently, hot air drying was carried out at 70 °C for 3 minutes to form a second adhesive layer with a thickness of 8 μm on the PET film. Through the above operations, a second adhesive film having a second adhesive layer on the PET film was obtained.

[0116] The first adhesive film and the second adhesive film were arranged such that their respective adhesive layers faced each other, and while heating at 40 °C together with the PET film serving as the base material, they were laminated using a roll laminator. Thereby, a circuit connection adhesive film with a PET film, which has a two-layer structure in which the first adhesive layer and the second adhesive layer are laminated, was fabricated.

[0117] The thickness of the first adhesive layer of the fabricated circuit connection adhesive film was measured by the following method. First, sandwich the circuit connection adhesive film between two pieces of glass (thickness: about 1 mm), and cast it with a resin composition consisting of 100 g of bisphenol A type epoxy resin (trade name: JER811, manufactured by Mitsubishi Chemical Corporation) and 10 g of a curing agent (trade name: Epomount curing agent, manufactured by Refine Tech Co., Ltd.). Then, perform cross-section polishing using a polishing machine, and measure the thickness of the first adhesive layer located at the separated part between adjacent conductive particles using a scanning electron microscope (SEM, trade name: SE-8020, manufactured by Hitachi High-Technologies Corporation). The thickness of the first adhesive layer was 2 μm.

[0118] <Production of Adhesive Tape and Adhesive Reel> The produced circuit connection adhesive film with a PET film was cut into an adhesive tape with a width of 1.0 mm using roll-to-roll slitting equipment. This adhesive tape was wound around a reel having a pair of side plates. At this time, for Examples 1 to 5, 8 and Comparative Examples 1 to 3, an adhesive reel was produced by winding the second adhesive layer, the first adhesive layer, and the PET film in this order from the core side, and for Examples 6, 7, and Comparative Example 4, an adhesive reel was produced by winding the first adhesive layer, the second adhesive layer, and the PET film in this order.

[0119] <Evaluation> [Evaluation of Transferability] The adhesive tape pulled out from the produced adhesive reel was transferred to a COF (manufactured by FLEXSEED) with a pitch of 300 μm under the conditions of 60 °C, 0.5 MPa, and 0.5 seconds using a transfer device (trade name LD-06, manufactured by Ohashi Seisakusho Co., Ltd.) and a temporary crimping tool equipped with a cushion material (trade name TC-20A, manufactured by Shin-Etsu Chemical Co., Ltd.). After transferring the circuit connection adhesive film, it was observed using a microscope (trade name ECLIPSE L300, manufactured by Nikon Corporation) whether the space between the electrodes of the COF was filled with resin. When the ratio of the area not filled with resin to the total area of the contact surface between the circuit connection adhesive film and the COF was 10% or less, the evaluation was S; when it was more than 10% and 20% or less, the evaluation was A; when it was more than 20% and 50% or less, the evaluation was B; and when it was more than 50%, the evaluation was C. The evaluation results are shown in Table 3.

[0120] [Evaluation of blocking resistance] The obtained adhesive reel was placed horizontally (the direction in which the core of the adhesive reel is perpendicular to the bottom surface of the thermostatic chamber) in a thermostatic chamber at 30°C for 24 hours. Then, the presence or absence of transfer (blocking) to the back surface when pulling out the adhesive tape from the adhesive reel was confirmed. The number of samples was 5 reels, and the blocking resistance was evaluated based on the number of reels of the sample in which no transfer to the back surface was observed. When the number of reels of the sample with transfer to the back surface was 0, it was evaluated as A, when it was 1 or more and 2 or less, it was evaluated as B, and when it was 3 or more, it was evaluated as C. The evaluation results are shown in Table 3.

[0121] [Evaluation of melt viscosity] The film-shaped adhesives prepared in Examples 4 and 8 and Comparative Examples 1 and 2 were laminated together at 70°C in a plurality of sheets to form a laminate having a thickness of 1000 μm (1 mm) or more. A measurement sample having a circular surface with a diameter of 9 mm was punched out from the laminate, and the measurement sample was attached onto a circular aluminum plate jig with a diameter of 8 mm. Using ARES (manufactured by TA Instruments Japan Co., Ltd.), the melt viscosity of the measurement sample was measured under the following conditions. The measurement results are shown in Figure 4. The lower the melt viscosity value, the higher the fluidity and the better the embedding property. It was confirmed from Figure 4 that there was almost no difference in melt viscosity between the examples and the comparative examples. (Measurement conditions) · Measurement temperature: 0 to 150°C · Heating rate: 5°C / min · Strain: 5% · Frequency: 4 Hz · Initial load: 10 g

[0122]

Table 3

Explanation of symbols

[0123] 1... Adhesive film for circuit connection, 2... First adhesive layer, 3... Second adhesive layer, 4... Conductive particles, 10... Circuit connection structure, 12... Circuit electrode (first electrode), 13... First circuit member, 15... Bump electrode (second electrode), 16... Second circuit member.

Claims

1. An adhesive film for circuit connection, comprising a radically polymerizable compound, a polymerization initiator, and conductive particles, wherein the radically polymerizable compound includes a radically polymerizable compound A1 having a linear alkyl structure and a melting point of 0 to 60°C.

2. The adhesive film for circuit connection according to claim 1, wherein the linear alkyl structure has 12 to 22 carbon atoms.

3. The adhesive film for circuit connection according to claim 1, wherein the radically polymerizable compound A1 is a (meth)acrylate compound.

4. The adhesive film for circuit connection according to claim 1, wherein the content of the radically polymerizable compound A1 is 1 to 50% by mass based on the total mass of the radically polymerizable compound.

5. Comprising a first adhesive layer and a second adhesive layer laminated on the first adhesive layer, wherein at least one of the first adhesive layer and the second adhesive layer contains the radically polymerizable compound A1. The adhesive film for circuit connection according to claim 1.

6. An adhesive film for circuit connection, comprising a radically polymerizable compound, a polymerization initiator, and conductive particles, wherein the radically polymerizable compound includes a radically polymerizable compound A2 having a linear alkyl structure and 12 to 22 carbon atoms in the linear alkyl structure.

7. The adhesive film for circuit connection according to claim 6, wherein the radically polymerizable compound A2 is a (meth)acrylate compound.

8. The adhesive film for circuit connection according to claim 6, wherein the content of the radically polymerizable compound A2 is 1 to 50% by mass based on the total mass of the radically polymerizable compound.

9. Comprising a first adhesive layer and a second adhesive layer laminated on the first adhesive layer, wherein at least one of the first adhesive layer and the second adhesive layer contains the radically polymerizable compound A2. The adhesive film for circuit connection according to claim 6.

10. The adhesive film for circuit connection according to any one of claims 1 to 9, wherein the radically polymerizable compound further includes a (poly)urethane (meth)acrylate compound.

11. The adhesive film for circuit connection according to any one of claims 1 to 9, further containing a thermoplastic resin.

12. The adhesive film for circuit connection according to any one of claims 1 to 9, further containing a coupling agent.

13. The adhesive film for circuit connection according to any one of claims 1 to 9, further containing a filler.

14. A first circuit member having a first electrode; A second circuit member having a second electrode; A circuit connection portion disposed between the first circuit member and the second circuit member, and electrically connecting the first electrode and the second electrode to each other; Comprising: The circuit connection structure, wherein the circuit connection portion includes a cured product of the adhesive film for circuit connection according to any one of claims 1 to 9.

15. A step of preparing a first circuit member having a first electrode, a second circuit member having a second electrode, and an adhesive film for circuit connection with a substrate provided with the adhesive film for circuit connection according to any one of claims 1 to 9 on the substrate; A step of transferring the adhesive film for circuit connection from the substrate onto the surface of the first circuit member where the first electrode is formed; A step of arranging the first circuit member, the adhesive film for circuit connection, and the second circuit member in this order such that the first electrode and the second electrode face each other, and then thermocompression bonding the first circuit member and the second circuit member to electrically connect the first electrode and the second electrode to each other; A method for manufacturing a circuit connection structure, comprising:

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