Method for manufacturing wound body of adhesive film for circuit connection, and wound body of adhesive film for circuit connection

Abstract

This method is for manufacturing a wound body of an adhesive film for circuit connection having base materials, and having, on the base materials, a first adhesive agent layer containing a thermosetting composition and a second adhesive agent layer containing conductive particles and a thermosetting composition. The method comprises: a step S1 for preparing a roll-shaped raw film obtained by winding a lamination body having, in the following order, a first base material, the first adhesive agent layer containing the thermosetting composition, the second adhesive agent layer containing the conductive particles and the thermosetting composition, and a second base material; and a step S2 for obtaining the wound body of the adhesive film for circuit connection by winding the lamination body on a winding core after going through processing including cutting, to a prescribed width, the lamination body unwound from the roll-shaped raw film, and peeling off one of the first base material and the second base material. In the step S2, winding the lamination body from which said one of the first base material and the second base material has been peeled off is performed only once.

Description

Method for manufacturing a roll of adhesive film for circuit connection, and roll of adhesive film for circuit connection

[0001] The present invention relates to a method for producing a roll of an adhesive film for circuit connection, and to a roll of an adhesive film for circuit connection.

[0002] Conventionally, various adhesive materials have been used for circuit connection. For example, anisotropically conductive adhesive films for circuit connection, in which conductive particles are dispersed in the adhesive, have been used as adhesive materials for connecting a liquid crystal display and a tape carrier package (TCP), connecting a flexible printed circuit board (FPC) and a TCP, or connecting an FPC and a printed wiring board.

[0003] In recent years, in the field of precision electronic devices, the density of circuits has increased, and the electrode width and electrode spacing have become extremely narrow. When connecting such circuits using an adhesive film for circuit connection, it is necessary to ensure insulation between adjacent circuit electrodes while capturing as many conductive particles as possible between opposing circuit electrodes to reduce connection resistance.

[0004] Techniques for improving the conductive particle capture ability of adhesive films containing conductive particles have been studied in the past, and for example, an adhesive film for circuit connection has been proposed that has two layers: a conductive adhesive layer containing conductive particles and an insulating adhesive layer (see, for example, Patent Document 1 below).

[0005] International Publication No. 2019-050012

[0006] Adhesive films for circuit connection are usually used in the form of a laminate in which an adhesive layer is provided on a substrate such as a polyethylene terephthalate (PET) film, and the laminate is cut into strips (or tapes) of a width suitable for the intended use. Such adhesive films for circuit connection are supplied as wound bodies (e.g., reels) wound around a core.

[0007] The adhesive film for circuit connection having the above-mentioned multilayer adhesive layer is also supplied and used as a roll, but the inventors' investigations have revealed that differences in the process for manufacturing the roll result in differences in the conductive particle capture ability of the adhesive film for circuit connection.

[0008] SUMMARY OF THE INVENTION It is therefore a primary object of the present invention to provide a roll of an adhesive film for circuit connection having the desired conductive particle capturing properties, and a method for producing the same.

[0009] The present invention provides the following inventions [1] to [8]: [1] A method for producing a roll of an adhesive film for circuit connection having a substrate and, provided on the substrate, a first adhesive layer containing a thermosetting composition and a second adhesive layer containing conductive particles and the thermosetting composition, the method comprising: a step S1 of preparing a roll of raw material around which a laminate having, in this order, the first substrate, the first adhesive layer containing a thermosetting composition, the second adhesive layer containing conductive particles and the thermosetting composition, and a second substrate is wound; and a step S2 of cutting the laminate unwound from the roll of raw material to a predetermined width and peeling off one of the first substrate and the second substrate, and then winding the laminate around a core to obtain a roll of adhesive film for circuit connection, wherein in step S2, the laminate from which one of the first substrate and the second substrate has been peeled is wound only once. [2] The method for producing a roll of an adhesive film for circuit connection according to [1], wherein the second substrate is peeled off in step S2. [3] The method for producing a roll of an adhesive film for circuit connection according to [1] or [2], wherein step S2 includes cutting the laminate from which one of the first substrate and the second substrate has been peeled off to a width of 0.5 to 3 mm. [4] A roll of an adhesive film for circuit connection, comprising a substrate and an adhesive layer provided on the substrate, wound around a core, wherein the adhesive layer comprises a first adhesive layer containing a thermosetting composition and a second adhesive layer containing conductive particles and a thermosetting composition, and wherein when the adhesive film for circuit connection is unwound from the roll, the root mean square height of the surface of the adhesive layer opposite to the substrate side is 0.005 to 0.1 μm. [5] The roll according to [4], wherein, when the adhesive film for circuit connection is unwound from the roll, the kurtosis of the surface of the adhesive layer opposite the substrate side is 2.8 to 4. [6] The roll according to [4] or [5], wherein the second adhesive layer further contains a cured product of a photocurable resin component. [7] The roll according to any of [4] to [6], wherein the adhesive film for circuit connection has the substrate, the first adhesive layer, and the second adhesive layer in this order.[8] A raw sheet for forming an adhesive film for circuit connection, comprising: a first substrate; a first adhesive layer containing a thermosetting composition; a second adhesive layer containing conductive particles and a thermosetting composition; and a wound body obtained by winding a laminate having the second substrate in this order around a core.

[0010] According to the manufacturing method described in [1], a roll of an adhesive film for circuit connection having the desired conductive particle capturing properties can be produced. The reason for this effect is that, in the process from preparing a roll-shaped raw material to obtaining a roll of the adhesive film for circuit connection, winding up the laminate from which one of the first substrate and the second substrate has been peeled off is performed only at the end of step S2. This prevents the surface condition of the adhesive layer on the side opposite the substrate, which is the surface to be attached to the circuit component, from becoming too rough when the adhesive film for circuit connection is unwound from the roll, thereby preventing a decrease in the conductive particle capturing properties. Note that, in step S2, if the laminate is subjected to one or more of the following processes, for example, cutting to a predetermined width, inspection such as foreign matter inspection, and light irradiation, these processes may be performed on the laminate unwound with the adhesive layer disposed between the two substrates, or on the laminate from which one of the first substrate and the second substrate has been peeled off.

[0011] According to the rolled body of the adhesive film for circuit connection described in [4], the surface of the adhesive layer opposite the substrate side, which is the surface to be attached to the circuit component, has the above-mentioned specific root mean square height, and therefore can have the desired conductive particle capturing properties.

[0012] According to the present invention, it is possible to provide a roll of an adhesive film for circuit connection having the desired conductive particle capturing properties, and a method for producing the same.

[0013] FIG. 1 is a schematic cross-sectional view showing one embodiment of a rolled body of an adhesive film for circuit connection. FIG. 2 is an enlarged schematic cross-sectional view showing one embodiment of an adhesive film for circuit connection. FIG. 3 is an enlarged schematic cross-sectional view showing another embodiment of an adhesive film for circuit connection. FIG. 4 is a perspective view showing an example of step S1 in one embodiment of a method for producing a rolled body of an adhesive film for circuit connection. FIG. 5 is an enlarged schematic cross-sectional view for explaining step S1 shown in FIG. 4. FIG. 6 is a perspective view showing an example of step S2 in one embodiment of a method for producing a rolled body of an adhesive film for circuit connection. FIG. 7 is a perspective view showing an example of step S2 in one embodiment of a method for producing a rolled body of an adhesive film for circuit connection. FIG. 8 is an enlarged schematic cross-sectional view for explaining an example of step S2 shown in FIG. 7.

[0014] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the same or equivalent parts will be designated by the same reference numerals, and duplicated explanations will be omitted. Note that the present invention is not limited to the following embodiment.

[0015] In this specification, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range may be replaced with the upper or lower limit of another numerical range. Furthermore, in numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with a value shown in the examples. Furthermore, individually described upper and lower limits can be arbitrarily combined. In the expression "A to B," the numerical values ​​A and B at both ends are included as the lower and upper limits, respectively, in the numerical range. In this specification, for example, the expression "10 or more" means "10" and "a number greater than 10," and this also applies when the numerical values ​​are different. Furthermore, for example, the expression "10 or less" means "10" and "a number less than 10," and this also applies when the numerical values ​​are different. Furthermore, in this specification, "(meth)acrylate" means at least one of acrylate and its corresponding methacrylate. The same applies to other similar expressions such as "(meth)acryloyl" and "(meth)acrylic acid." Furthermore, "A or B" may contain either A or B, or may contain both. Furthermore, unless otherwise specified, the materials exemplified below may be used alone or in combination of two or more. When a plurality of substances corresponding to each component are present in the composition, the content of each component in the composition means the total amount of the plurality of substances present in the composition, unless otherwise specified.

[0016] <Roll of adhesive film for circuit connection> The roll of adhesive film for circuit connection of this embodiment is a roll in which an adhesive film for circuit connection having a substrate and an adhesive layer provided on the substrate is wound around a winding core, the adhesive layer comprising a first adhesive layer containing a thermosetting composition and a second adhesive layer containing conductive particles and a thermosetting composition. The adhesive film for circuit connection may be wound around the winding core so that the substrate is on the outside, or may be wound around the winding core so that the substrate is on the inside.

[0017] The roll of the adhesive film for circuit connection of this embodiment can be used, for example, in the following method for producing a circuit connection structure. The method for producing a circuit connection structure includes the steps of interposing an adhesive layer in the adhesive film for circuit connection unwound from the roll between a first circuit member having a first electrode (circuit electrode) and a second circuit member having a second electrode (circuit electrode), and thermocompression bonding the first circuit member and the second circuit member to electrically connect the first electrode and the second electrode to each other. In this case, the adhesive layer of the adhesive film for circuit connection functions as an anisotropically conductive adhesive layer.

[0018] The above method may include a laminating step of laminating the adhesive film for circuit connection unwound from a roll onto a first circuit member while the film has a substrate so that the adhesive layer contacts the first circuit member, a peeling step of peeling the substrate from the adhesive film for circuit connection attached to the first circuit member, and a heating and pressurizing step of placing a second circuit member on the first circuit member to which the adhesive layer has been laminated so that the first electrode and the second electrode face each other, and, while heating the adhesive layer, pressurizing the first circuit member and the second circuit member in a direction in which the first electrode and the second electrode face each other. The laminating and peeling steps may also be changed to steps of laminating the first circuit member after or while peeling the substrate.

[0019] 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 used. After the pre-lamination, pressure bonding can be performed using a thermocompression bonding device.

[0020] As the heating means, a known thermocompression bonding device can be used. As the pressure applying means, a known thermocompression bonding device can be used.

[0021] Fig. 1 is a cross-sectional view showing an example of a roll of the adhesive film for circuit connection according to this embodiment. The roll 100 shown in Fig. 1 has a configuration in which an adhesive film for circuit connection 60 having a substrate 101 and an adhesive layer 102 provided on the substrate 101 is wound around the outer surface F1 of a winding core 110. The adhesive film for circuit connection 60 is wound so that the adhesive layer 102 faces the winding core 110 and the substrate 101 faces outward. In the roll 100, the inner surface S2 of the adhesive layer 102 is in contact with the outer surface F1 of the winding core 110 or the outer surface S1 of the substrate 101.

[0022] The substrate 101 may be, for example, a substrate (e.g., a film) made of a polyolefin such as oriented polypropylene (OPP), polyethylene terephthalate (PET), polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyethylene, or polypropylene, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, polyimide, cellulose, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, synthetic rubber, or liquid crystal polymer. The substrate may contain any filler. Examples of fillers include oxides such as titanium oxide. The surface of the substrate may also be subjected to a release treatment, plasma treatment, or the like.

[0023] The wound body 100 of the adhesive film for circuit connection may be used as a reel body. The configuration of the reel body is not particularly limited and any known configuration can be adopted, but it may, for example, include a winding core 110, a pair of side plates provided at both ends of the winding core so as to face each other, and the wound body 100 of the adhesive film for circuit connection according to the present embodiment wound around the winding core. Note that, although the adhesive film for circuit connection 60 (i.e., the adhesive films for circuit connection 56 and 58) is wound around the winding core 110 with the substrate 101 facing outward in FIG. 1 , the wound body of the adhesive film for circuit connection may also be used as a reel body in the same way even if the adhesive film for circuit connection 60 is wound around the winding core 110 with the substrate 101 facing inward.

[0024] The thickness of the adhesive film for circuit connection (in FIG. 1, the total thickness of the substrate 101 and adhesive layer 102) may be, for example, 5.0 μm or more, 8.0 μm or more, 10.0 μm or more, 25.0 μm or more, 35.0 μm or more, or 45.0 μm or more, and may be 100.0 μm or less, 80.0 μm or less, 70.0 μm or less, 60.0 μm or less, or 40.0 μm or less.

[0025] The thickness of the adhesive layer in the adhesive film for circuit connection (in FIG. 1, the thickness of adhesive layer 102) may be, for example, 2.0 μm or more, 5.0 μm or more, 6.0 μm or more, or 7.0 μm or more, and may be 40.0 μm or less, 20.0 μm or less, 10.0 μm or less, or 3.0 μm or less.

[0026] From the viewpoint of facilitating trapping of conductive particles between electrodes, the roll of the adhesive film for circuit connection may have a root mean square height (Sq) of 0.005 to 0.1 μm on the surface of the adhesive layer opposite the substrate side (surface S2 of adhesive layer 102 in FIG. 1 ) when the adhesive film for circuit connection is unwound from the roll. Furthermore, from the viewpoint of facilitating unwinding of the adhesive film for circuit connection from the roll, Sq may be 0.005 μm or more, or 0.001 μm or more, and from the viewpoint of facilitating trapping of conductive particles between electrodes, Sq may be 0.1 μm or less, or 0.05 μm or less. Furthermore, by having Sq satisfy the above upper limit, the ease of peeling the substrate from the adhesive film for circuit connection after thermocompression bonding the adhesive film for circuit connection to a circuit component or the like without peeling the substrate (hereinafter, sometimes referred to as "reworkability of the substrate") may be improved.

[0027] A circuit connection structure obtained using an adhesive film for circuit connection may be required to have a property (hereinafter, sometimes referred to as "connection reliability") in which the connection resistance between connected electrodes does not increase easily, even after a reliability test under high-temperature, high-humidity conditions (for example, a temperature of 85°C and a humidity of 85%). From the viewpoints of connection reliability and conductive particle capture ability, a roll of an adhesive film for circuit connection may have a kurtosis (Sku) of 2.8 to 4, or 2.9 to 3.5, on the surface of the adhesive layer opposite the substrate side (surface S2 of adhesive layer 102 in Figure 1) when the adhesive film for circuit connection is unwound from the roll.

[0028] From the viewpoints of connection reliability and conductive particle capture ability, when the adhesive film for circuit connection is unwound from the roll, the arithmetic mean height (Sa) of the surface of the adhesive layer opposite the substrate side (surface S2 of adhesive layer 102 in FIG. 1 ) may be 0.005 to 0.1 μm, 0.005 to 0.05 μm, or 0.005 to 0.03 μm.

[0029] From the viewpoints of connection reliability and conductive particle capture ability, when the adhesive film for circuit connection is unwound from the roll, the skewness (Ssk) of the surface of the adhesive layer opposite the substrate side (surface S2 of adhesive layer 102 in FIG. 1 ) may be −0.9 to 0, or −0.8 to 0, or −0.7 to 0.

[0030] In FIG. 1, the adhesive film 60 for circuit connection is wound around the core 110 with the substrate 101 facing outward, but even when the adhesive film 60 for circuit connection is wound around the core 110 with the substrate 101 facing inward, the Sq, Sku, Sa, and Ssk of the above-mentioned surface of the adhesive film for circuit connection may be the same as the above-mentioned numerical ranges.

[0031] Sq, Sku, Sa, and Ssk can be determined, for example, by the method described in the Examples. Specifically, a laser microscope OLS4100 (manufactured by Olympus) is used to photograph the surface of the adhesive layer of the adhesive film for circuit connection unwound from the roll, opposite the substrate side, and the surface roughness parameters can be calculated using the attached surface analysis software. Note that the photograph can be taken at a magnification of 100x using an objective lens. Furthermore, in the attached surface analysis software, the cutoff wavelength during analysis, λs, can be set to 25 μm, and λc and λf do not need to be set.

[0032] In a roll of the adhesive film for circuit connection of this embodiment, from the viewpoint of facilitating connection reliability and conductive particle capture, when the adhesive film for circuit connection is unwound from the roll, the surface of the substrate opposite the adhesive layer side (surface S1 of substrate 101 in FIG. 1 ) may have a root mean square height (Sq) of 0.005 to 0.3 μm, 0.005 to 0.1 μm, or 0.005 to 0.01 μm. Furthermore, when Sq satisfies the above range, the reworkability of the substrate is more easily obtained.

[0033] In a roll of the adhesive film for circuit connection of this embodiment, from the viewpoint of facilitating connection reliability and conductive particle capture, when the adhesive film for circuit connection is unwound from the roll, the arithmetic mean height (Sa) of the surface of the substrate opposite the adhesive layer side (surface S1 of substrate 101 in FIG. 1 ) may be 0.005 to 0.2 μm, 0.005 to 0.1 μm, or 0.005 to 0.01 μm. Furthermore, when Sa satisfies the above range, reworkability of the substrate is more easily obtained.

[0034] In FIG. 1, the adhesive film 60 for circuit connection is wound around the winding core 110 with the substrate 101 facing outward, but even when the adhesive film 60 for circuit connection is wound around the winding core 110 with the substrate 101 facing inward, the Sq and Sa of the above-mentioned surface of the substrate may be the same as the above-mentioned numerical ranges.

[0035] The adhesive film for circuit connection according to this embodiment will be described in further detail below with reference to the drawings.

[0036] Fig. 2 is an enlarged cross-sectional view showing an example of an adhesive film for circuit connection. The adhesive film 56 for circuit connection shown in Fig. 2 includes a substrate 11 and an adhesive layer 102a provided on one side of the substrate 11. The adhesive layer 102a includes a first adhesive layer 12 containing a thermosetting composition and a second adhesive layer 22 containing a plurality of conductive particles 1 and an adhesive component 2 containing a thermosetting composition, in this order from the substrate 11 side. In the adhesive film 56 for circuit connection shown in Fig. 2, some of the conductive particles 1 are exposed from the surface of the second adhesive layer 22 (e.g., protruding toward the first adhesive layer 12). However, the conductive particles 1 may be entirely embedded in the second adhesive layer 22 so that they are not exposed from the surface of the second adhesive layer 22. In the adhesive film 56 for circuit connection shown in Fig. 2, the substrate 11 is peeled off during use.

[0037] Fig. 3 is an enlarged cross-sectional view showing another example of an adhesive film for circuit connection. The adhesive film 58 for circuit connection shown in Fig. 3 includes a substrate 21 and an adhesive layer 102b provided on one side of the substrate 21. The adhesive layer 102b includes, in this order from the substrate 21 side, a second adhesive layer 22 containing adhesive component 2 containing a plurality of conductive particles 1 and a thermosetting composition, and a first adhesive layer 12 containing a thermosetting composition. In Fig. 3, some of the conductive particles 1 are exposed from the surface of the second adhesive layer 22 (e.g., protruding toward the first adhesive layer 12). However, the conductive particles 1 may be entirely embedded in the second adhesive layer 22 so that they are not exposed from the surface of the second adhesive layer 22. In the adhesive film 58 for circuit connection, the substrate 21 is peeled off during use.

[0038] In the above-described method for manufacturing a circuit connection structure, the adhesive film for circuit connection 56 can be laminated to the first circuit member so that the second adhesive layer 22 contacts the first circuit member, and the adhesive film for circuit connection 58 can be laminated to the first circuit member so that the first adhesive layer 12 contacts the first circuit member.

[0039] The same materials as those described above can be used for the substrates 11 and 21. The Sq and Sa of the surfaces of the substrates 11 and 21 opposite to the adhesive layer side may also be within the same ranges as those described above.

[0040] In the adhesive film for circuit connection 56, the surface of the second adhesive layer 22 opposite the substrate 11 side may satisfy any one of the above-mentioned conditions of Sq, Sku, Sa, and Ssk. In the adhesive film for circuit connection 58, the surface of the first adhesive layer 12 opposite the substrate 21 side may satisfy any one of the above-mentioned conditions of Sq, Sku, Sa, and Ssk.

[0041] Next, the components constituting the first adhesive layer 12 and the second adhesive layer 22 will be described.

[0042] (First adhesive layer) The first adhesive layer may be an insulating adhesive layer composed of a non-conductive component (insulating resin component). The first adhesive layer contains a thermosetting composition. The thermosetting composition is a composition that is at least partially cured by heat, and may contain a thermosetting resin component (hereinafter, sometimes referred to as "component (A)").

[0043] [Component (A): Thermosetting Resin Component] The component (A) is not particularly limited as long as it is a resin component that is cured by heat, and may contain, for example, a cationically polymerizable compound (hereinafter sometimes referred to as "component (A1)") and a thermal cationic polymerization initiator (hereinafter sometimes referred to as "component (A2)"). The component (A) may be a component consisting of the components (A1) and (A2).

[0044] Component (A1): Cationic Polymerizable Compound Component (A1) is a compound that crosslinks by reacting with component (A2) under heat. Component (A1) refers to a compound that does not have a radically polymerizable group that reacts with a radical, and is not included in component (F1). Examples of component (A1) include compounds having a cyclic ether group, such as oxetane compounds and epoxy compounds. Component (A1) may be used alone or in combination. From the viewpoint of further improving the effect of reducing connection resistance and achieving more excellent connection reliability, component (A1) may contain, for example, at least one selected from the group consisting of oxetane compounds and alicyclic epoxy compounds. Component (A1) may contain both at least one oxetane compound and at least one alicyclic epoxy compound, from the viewpoint of easily achieving a desired melt viscosity.

[0045] The oxetane compound as component (A1) can be any compound that has an oxetanyl group and no radically polymerizable group, and is not particularly limited. Commercially available oxetane compounds include ETERNACOLL OXBP (trade name, 4,4'-bis[(3-ethyl-3-oxetanyl)methoxymethyl]biphenyl, manufactured by Ube Industries, Ltd.), OXSQ, OXT-121, OXT-221, OXT-101, and OXT-212 (trade names, manufactured by Toagosei Co., Ltd.). These compounds may be used alone or in combination.

[0046] The alicyclic epoxy compound as component (A1) can be any compound that has an alicyclic epoxy group (e.g., an epoxycyclohexyl group) and does not have a radically polymerizable group, and can be used without any particular limitation. Commercially available alicyclic epoxy compounds include EHPE3150, EHPE3150CE, CELLOXIDE 8010, CELLOXIDE 2021P, and CELLOXIDE 2081 (trade names, manufactured by Daicel Corporation). These compounds may be used alone or in combination.

[0047] Component (A2): Thermal Cationic Polymerization Initiator The component (A2) is a thermal polymerization initiator that generates an acid or the like upon heating to initiate polymerization. The component (A2) may be a salt compound composed of a cation and an anion. The component (A2) may be, for example, BF ４ － , B.R. ４ － (R represents a phenyl group substituted with two or more fluorine atoms or two or more trifluoromethyl groups), PF ６ － , SbF ６ － , AsF ６ － and onium salts such as sulfonium salts, phosphonium salts, ammonium salts, diazonium salts, iodonium salts, anilinium salts, and pyridinium salts, each of which has an anion such as any of the above. These may be used alone or in combination of two or more.

[0048] From the viewpoint of storage stability, the component (A2) is, for example, an anion containing boron as a constituent element, i.e., BF ４ － or BR ４ － (R represents a phenyl group substituted with two or more fluorine atoms or two or more trifluoromethyl groups). An anion containing boron as a constituent element may be a salt compound having BR ４ -, and more specifically, it may be tetrakis(pentafluorophenyl)borate.

[0049] The onium salt as component (A2) may be, for example, an anilinium salt, since it is resistant to substances that can inhibit cationic curing. Examples of anilinium salt compounds include N,N-dialkylanilinium salts such as N,N-dimethylanilinium salt and N,N-diethylanilinium salt.

[0050] Component (A2) may be an anilinium salt having an anion containing boron as a constituent element. Commercially available products of such salt compounds include CXC-1821 (trade name, manufactured by King Industries).

[0051] From the viewpoint of ensuring the formability and curability of the first adhesive layer, the content of the (A2) component may be, for example, 0.001 to 1 part by mass, 0.005 to 0.7 parts by mass, 0.01 to 0.5 parts by mass, or 0.03 to 0.3 parts by mass per 100 parts by mass of the (A1) component.

[0052] From the viewpoint of maintaining reliability, the content of component (A) may be 5% by mass or more, 10% by mass or more, 15% by mass or more, or 20% by mass or more, based on the total mass of the first adhesive layer. From the viewpoint of preventing resin seepage problems in a reel, which is one embodiment of the supply form, the content of component (A) may be 80% by mass or less, 70% by mass or less, 60% by mass or less, or 50% by mass or less, based on the total mass of the first adhesive layer. When the content of component (A) is within the above range, the effects of the present invention tend to be significantly achieved.

[0053] [Other Components] The first adhesive layer may further contain other components, such as a thermoplastic resin (hereinafter sometimes referred to as "component (B)"), a coupling agent (hereinafter sometimes referred to as "component (C)"), and a filler (hereinafter sometimes referred to as "component (D)").

[0054] Examples of the (B) component include phenoxy resin, polyester resin, polyamide resin, polyurethane resin, polyester urethane resin, acrylic rubber, and epoxy resin (solid at 25°C). These may be used alone or in combination. Among these, the (B) component may be, for example, a phenoxy resin. The content of the (B) component may be 1% by mass or more, 3% by mass or more, or 5% by mass or more, and may be 60% by mass or less, 40% by mass or less, or 20% by mass or less, based on the total mass of the first adhesive layer.

[0055] Examples of component (C) include silane coupling agents having organic functional groups such as (meth)acryloyl groups, mercapto groups, amino groups, imidazole groups, and epoxy groups; silane compounds such as tetraalkoxysilanes; tetraalkoxytitanate derivatives; and polydialkyltitanate derivatives. These may be used alone or in combination. By including component (C) in the first adhesive layer, adhesion can be further improved. Component (C) may be, for example, a silane coupling agent. The content of component (C) may be 0.1 to 10% by mass, based on the total mass of the first adhesive layer.

[0056] Examples of the (D) component include non-conductive fillers (e.g., non-conductive particles). The (D) component may be either an inorganic filler or an organic filler. Examples of inorganic fillers include inorganic fine particles such as metal oxide fine particles such as silica fine particles, alumina fine particles, silica-alumina fine particles, titania fine particles, and zirconia fine particles; and metal nitride fine particles. Examples of organic fillers 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 may be used alone or in combination. The (D) component may be, for example, silica fine particles. The content of the (D) component may be 1% by mass or more, 10% by mass or more, or 30% by mass or more, based on the total mass of the first adhesive layer, and may be 90% by mass or less, 70% by mass or less, or 50% by mass or less.

[0057] [Other Additives] The first adhesive layer may further contain other additives such as a softener, an accelerator, an anti-degradant, a colorant, a flame retardant, a thixotropic agent, etc. The content of the other additives may be, for example, 0.1 to 10 mass % based on the total mass of the first adhesive layer.

[0058] The thickness of the first adhesive layer may be appropriately set depending on the height of the electrodes of the circuit components to be bonded. The thickness of the first adhesive layer may be 5.0 μm or more or 6.0 μm or more, and may be 30.0 μm or less, 20.0 μm or less, 15.0 μm or less, or 13.0 μm or less, from the viewpoint of being able to sufficiently fill the space between the electrodes and seal the electrodes, thereby obtaining better connection reliability. As shown in FIGS. 2 and 3 , when a portion of the conductive particles 1 contained in the second adhesive layer 22 is exposed from the surface of the second adhesive layer 22 (for example, protruding toward the first adhesive layer 12), the distance from the surface of the first adhesive layer 12 opposite the second adhesive layer 22 to the boundary between the second adhesive layer 22 and the first adhesive layer 12 located in the space between adjacent conductive particles 1 (the distance indicated by d2 in FIGS. 2 and 3 ) is the thickness of the first adhesive layer 12.

[0059] The thickness of the first adhesive layer can be determined, for example, by the method described in the Examples. Specifically, the adhesive film for circuit connection is sandwiched between two sheets of glass (thickness: approximately 1 mm), and a resin composition consisting of 100 g of bisphenol A 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.) is poured into the mold. The cross section is then polished using a polishing machine, and the thickness can be measured using a scanning electron microscope (SEM, trade name: SE-8020, manufactured by Hitachi High-Tech Science Corporation). This operation can be performed multiple times, and the average value can be used as the thickness of the first adhesive layer.

[0060] (Second Adhesive Layer) The second adhesive layer contains conductive particles (hereinafter sometimes referred to as "component (E)") and a thermosetting composition. The second adhesive layer may contain a non-conductive component other than component (E) (e.g., an insulating resin component). The thermosetting composition is a composition that is at least partially cured by heat and may contain the above-mentioned component (A). The second adhesive layer may further contain a photocurable resin component (hereinafter sometimes referred to as "component (F)"). When the second adhesive layer contains component (F), the second adhesive layer may contain a cured product of component (F). The cured product of component (F) may be a cured product obtained by completely curing component (F) or a cured product obtained by partially curing component (F). The second adhesive layer can be obtained, for example, by irradiating a composition layer containing component (E), a thermosetting composition, and a composition containing component (F) with light energy to polymerize the components contained in component (F) and form a cured product of component (F). The thermosetting composition is a component that is flowable when the circuit is connected.

[0061] [Component (E): Conductive Particles] Component (E) is not particularly limited as long as it is a conductive particle, and may be, for example, a metal particle made of a metal such as Au, Ag, Pd, Ni, Cu, or solder, or a conductive carbon particle made of conductive carbon. Component (E) may also be a coated conductive particle having a core containing non-conductive glass, ceramic, plastic (polystyrene, etc.), or the like, and a coating layer containing the metal or conductive carbon that coats the core. Component (E) may be one type of various conductive particles used alone, or a combination of multiple types. Component (E) may be a coated conductive particle having a core containing plastic and a coating layer containing metal or conductive carbon that coats the core, or a metal particle formed of a heat-fusible metal.

[0062] When component (E) is a coated conductive particle, the cured product of the thermosetting resin component can be easily deformed by heating or applying pressure. This increases the contact area between the electrodes and component (E) when electrically connecting the electrodes, thereby further improving the conductivity between the electrodes.

[0063] When component (E) is metal particles formed of a heat-fusible metal, the connection between the electrodes tends to be stronger, and this tendency is particularly pronounced when solder particles are used as component (E).

[0064] The solder particles may contain at least one selected from the group consisting of tin, a tin alloy, indium, and an indium alloy, from the viewpoint of achieving both connection strength and a low melting point. Furthermore, the solder particles may contain at least one selected from the group consisting of an In—Bi alloy, an In—Sn alloy, an In—Sn—Ag alloy, an Sn—Au alloy, an Sn—Bi alloy, an Sn—Bi—Ag alloy, an Sn—Ag—Cu alloy, and an Sn—Cu alloy, from the viewpoint of achieving higher reliability during a high-temperature, high-humidity test and a thermal shock test.

[0065] The component (E) may be an insulating coated conductive particle comprising the above-mentioned metal particle, the above-mentioned conductive carbon particle, or the above-mentioned coated conductive particle, and an insulating layer containing an insulating material such as a resin and coating the surface of the particle. When the component (E) is an insulating coated conductive particle, even if the content of the component (E) is high, the particle surface has an insulating layer, so that the occurrence of a short circuit due to contact between the components (E) can be suppressed and the insulation between adjacent electrode circuits can also be improved.

[0066] The maximum particle size of the (E) component must be smaller than the minimum electrode spacing (the shortest distance between adjacent electrodes). From the viewpoint of excellent dispersibility and conductivity, the maximum particle size of the (E) component may be 1.0 μm or more, 2.0 μm or more, or 2.5 μm or more. From the viewpoint of excellent dispersibility and conductivity, the maximum particle size of the (E) component may be 30.0 μm or less, 25.0 μm or less, 20.0 μm or less, 15.0 μm or less, 10.0 μm or less, or 5.0 μm or less. In this specification, the particle size of any 300 particles (pcs) of the (E) component in the second adhesive layer is measured by observation using a scanning electron microscope (SEM), and the largest value obtained is defined as the maximum particle size of the (E) component. Note that when the (E) component has protrusions or is not spherical, the particle size of the (E) component is defined as the diameter of a circle circumscribing the conductive particle in the SEM image.

[0067] The average particle size of the (E) component may be 1.0 μm or more, 2.0 μm or more, 2.5 μm or more, or 3.0 μm or more from the viewpoint of excellent dispersibility and conductivity. The average particle size of the (E) component may be 20.0 μm or less, 10.0 μm or less, 7.0 μm or less, or 5.0 μm or less from the viewpoint of excellent dispersibility and conductivity. In this specification, the particle size of any 300 particles (pcs) of the (E) component in the second adhesive layer is measured by observation using a scanning electron microscope (SEM), and the average value of the obtained particle sizes is defined as the average particle size.

[0068] In the second adhesive layer, the component (E) may be uniformly dispersed. From the viewpoint of obtaining a stable connection resistance, the particle density of the component (E) in the adhesive film for circuit connection is set to 100 particles / mm ２ More than 1000 pieces / mm ２ More than 3000 pieces / mm ２ More than 5000 pieces / mm ２ More than 7000 pieces / mm ２ More than 10,000 pieces / mm ２ or more than 12,000 pieces / mm ２ From the viewpoint of improving the insulating properties between adjacent electrodes, the particle density of the component (E) in the adhesive film for circuit connection may be 100,000 particles / mm ２ Below, 70,000 pieces / mm ２ Below, 50,000 pieces / mm ２ Below, 30000 pieces / mm ２ or less, or 20,000 pieces / mm ２ It may be the following:

[0069] The content of the (E) component may be 1% by mass or more, 5% by mass or more, or 10% by mass or more, based on the total mass of the second adhesive layer, from the viewpoint of further improving conductivity. The content of the (E) component may be 60% by mass or less, 50% by mass or less, or 40% by mass or less, based on the total mass of the second adhesive layer, from the viewpoint of easily suppressing short circuits. When the content of the (E) component is within the above range, the effects of the present invention tend to be significantly exhibited. Note that when the second adhesive layer contains the (F) component, the content of the (E) component in the composition or composition layer containing the (E) component, the thermosetting composition, and the (F) component (based on the total mass of the composition or composition layer) may be the same as the above range.

[0070] [Component (A): Thermosetting Resin Component] The components (A1) and (A2) used in the component (A) in the second adhesive layer are the same as the components (A1) and (A2) used in the component (A) in the first adhesive layer. The component (A) in the second adhesive layer may be the same as or different from the component (A) in the first adhesive layer.

[0071] The content of the (A) component may be 5% by mass or more, 10% by mass or more, 15% by mass or more, or 20% by mass or more, based on the total mass of the second adhesive layer, from the viewpoint of ensuring the curability of the second adhesive layer. The content of the (A) component may be 70% by mass or less, 60% by mass or less, 50% by mass or less, or 40% by mass or less, based on the total mass of the second adhesive layer, from the viewpoint of ensuring the formability of the second adhesive layer. When the content of the (A) component is within the above range, the effects of the present invention tend to be significantly enhanced. When the second adhesive layer contains the (F) component, the content of the (A) component in the composition or composition layer containing the (E) component, the thermosetting composition, and the (F) component (based on the total mass of the composition or composition layer) may be the same as the above range.

[0072] [Component (F): Photocurable Resin Component] Component (F) is not particularly limited as long as it is a resin component that cures upon irradiation with light. However, when component (A) is a resin component having cationic curability, component (F) may be a resin component having radical curability from the viewpoint of achieving better connection resistance. Component (F) may contain, for example, a radical polymerizable compound (hereinafter sometimes referred to as "component (F1)") and a photoradical polymerization initiator (hereinafter sometimes referred to as "component (F2)"). Component (F) may be a component consisting of components (F1) and (F2).

[0073] Component (F1): Radically Polymerizable Compound Component (F1) is a compound that polymerizes due to radicals generated from component (F2) upon irradiation with light (e.g., ultraviolet light). Component (F1) may be either a monomer or a polymer (or oligomer) obtained by polymerizing one or more types of monomers. Component (F1) may be used alone or in combination.

[0074] The component (F1) is a compound having a radical polymerizable group that reacts with a radical. Examples of the radical polymerizable group include a (meth)acryloyl group, a vinyl group, an allyl group, a styryl group, an alkenyl group, an alkenylene group, and a maleimide group. The number of radical polymerizable groups (the number of functional groups) contained in the component (F1) may be 2 or more from the viewpoint of easily obtaining a desired melt viscosity after polymerization and achieving better connection reliability, and may be 10 or less, 6 or less, or 4 or less from the viewpoint of further improving the effect of reducing connection resistance and suppressing cure shrinkage during polymerization. In addition, in order to balance the crosslink density and cure shrinkage, in addition to a compound having the number of radical polymerizable groups within the above range, a compound having the number of radical polymerizable groups outside the above range may also be used.

[0075] From the viewpoint of suppressing the flow of the conductive particles, the component (F1) may contain a polyfunctional (difunctional or higher) (meth)acrylate. The polyfunctional (difunctional or higher) (meth)acrylate may be a difunctional or trifunctional (meth)acrylate, or may be a difunctional (meth)acrylate. The difunctional (meth)acrylate may be a difunctional aromatic (meth)acrylate.

[0076] Examples of polyfunctional (meth)acrylates include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetrapropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, ethoxylated polypropylene glycol di(meth)acrylate, and 1,3-butane. aliphatic (meth)acrylates such as diol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, glycerin di(meth)acrylate, tricyclodecane dimethanol (meth)acrylate, and ethoxylated 2-methyl-1,3-propanediol di(meth)acrylate;Aromatic (meth)acrylates such as ethoxylated bisphenol A di(meth)acrylate, propoxylated bisphenol A di(meth)acrylate, ethoxylated propoxylated bisphenol A di(meth)acrylate, ethoxylated bisphenol F di(meth)acrylate, propoxylated bisphenol F di(meth)acrylate, ethoxylated propoxylated bisphenol F di(meth)acrylate, ethoxylated fluorene di(meth)acrylate, propoxylated fluorene di(meth)acrylate, and ethoxylated propoxylated fluorene di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, ethoxylated propoxylated trimethylolpropane tri(meth)acrylate, pentaerythritol aliphatic (meth)acrylates such as pentaerythritol tri(meth)acrylate, ethoxylated pentaerythritol tri(meth)acrylate, propoxylated pentaerythritol tri(meth)acrylate, ethoxylated propoxylated pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, propoxylated pentaerythritol tetra(meth)acrylate, ethoxylated propoxylated pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetraacrylate, and dipentaerythritol hexa(meth)acrylate; aromatic epoxy (meth)acrylates such as bisphenol-type epoxy (meth)acrylate, phenol novolac-type epoxy (meth)acrylate, and cresol novolac-type epoxy (meth)acrylate;

[0077] From the viewpoint of achieving both the effect of reducing connection resistance and the suppression of particle flow, the content of the polyfunctional (difunctional or higher) (meth)acrylate may be, for example, 50 to 100 mass %, 70 to 100 mass %, or 90 to 100 mass %, or may even be 100 mass %, based on the total mass of the component (F1).

[0078] The component (F1) may further contain a monofunctional (meth)acrylate in addition to a polyfunctional (difunctional or higher) (meth)acrylate. Examples of the monofunctional (meth)acrylate include (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, butoxyethyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, heptyl (meth)acrylate, octylheptyl (meth)acrylate, and nonyl (meth)acrylate. Decyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, ethoxypolypropylene glycol (meth)acrylate, mono(2-(meth)acryloyloxy) aliphatic (meth)acrylates such as diethyl succinate; benzyl (meth)acrylate, phenyl (meth)acrylate, o-biphenyl (meth)acrylate, 1-naphthyl (meth)acrylate, 2-naphthyl (meth)acrylate, phenoxyethyl (meth)acrylate, p-cumylphenoxyethyl (meth)acrylate, o-phenylphenoxyethyl (meth)acrylate, 1-naphthoxyethyl (meth)acrylate, 2-naphthoxyethyl (meth)acrylate, phenoxypolyether aromatic (meth)acrylates such as ethylene glycol (meth)acrylate, nonylphenoxy polyethylene glycol (meth)acrylate, phenoxy polypropylene glycol (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-hydroxy-3-(o-phenylphenoxy)propyl (meth)acrylate, 2-hydroxy-3-(1-naphthoxy)propyl (meth)acrylate, and 2-hydroxy-3-(2-naphthoxy)propyl (meth)acrylate;Examples include (meth)acrylates having an epoxy group such as glycidyl (meth)acrylate, (meth)acrylates having an alicyclic epoxy group such as 3,4-epoxycyclohexylmethyl (meth)acrylate, and (meth)acrylates having an oxetanyl group such as (3-ethyloxetan-3-yl)methyl (meth)acrylate;

[0079] The content of the monofunctional (meth)acrylate may be, for example, 0 to 50 mass%, 0 to 30 mass%, or 0 to 10 mass%, or may even be 0 mass%, based on the total mass of the component (F1).

[0080] The cured product of component (F) may have, for example, a polymerizable group that reacts by a mechanism other than a radical. The polymerizable group that reacts by a mechanism other than a radical may be, for example, a cationically polymerizable group that reacts by a cation. Examples of the cationically polymerizable group include epoxy groups such as glycidyl groups, alicyclic epoxy groups such as epoxycyclohexylmethyl groups, and oxetanyl groups such as ethyloxetanylmethyl groups. The cured product of component (F) having a polymerizable group that reacts by a mechanism other than a radical can be introduced by using, for example, a (meth)acrylate having a polymerizable group that reacts by a mechanism other than a radical, such as a (meth)acrylate having an epoxy group, a (meth)acrylate having an alicyclic epoxy group, or a (meth)acrylate having an oxetanyl group, as component (F). From the viewpoint of improving reliability, the mass ratio of the (meth)acrylate having a polymerizable group that reacts by means other than radicals to the total mass of the component (F1) (mass (charge amount) of the (meth)acrylate having a polymerizable group that reacts by means other than radicals / total mass (charge amount) of the component (F1)) may be, for example, 0 to 0.7, 0 to 0.5, or 0 to 0.3.

[0081] The component (F1) may contain other radically polymerizable compounds in addition to polyfunctional (difunctional or higher) and monofunctional (meth)acrylates. Examples of other radically polymerizable compounds include maleimide compounds, vinyl ether compounds, allyl compounds, styrene derivatives, acrylamide derivatives, and nadimide derivatives. The content of other radically polymerizable compounds may be, for example, 0 to 40% by mass based on the total mass of the component (F1).

[0082] Component (F2): Photoradical Polymerization Initiator The component (F2) is a photopolymerization initiator that generates radicals when irradiated with light having a wavelength in the range of 150 to 750 nm, light having a wavelength in the range of 254 to 405 nm, or light having a wavelength of 365 nm (e.g., ultraviolet light). One type of component (F2) may be used alone, or multiple types may be used in combination.

[0083] The component (F2) decomposes when exposed to light to generate free radicals. That is, the component (F2) is a compound that generates radicals when exposed to external light energy. The component (F2) may be a compound having 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 benzyl dimethyl ketal structure, an α-hydroxyalkylphenone structure, or the like. The component (F2) may be used alone or in combination with multiple compounds. From the viewpoints of easily obtaining a desired melt viscosity and of achieving a superior effect of reducing connection resistance, the component (F2) may be a compound having at least one structure selected from the group consisting of an oxime ester structure, an α-aminoalkylphenone structure, and an acylphosphine oxide structure.

[0084] 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-acetyloxime), and the like.

[0085] Specific examples of compounds having an α-aminoalkylphenone structure include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-morpholinophenyl)-butanone-1, and the like.

[0086] Specific examples of compounds having an acylphosphine oxide structure include bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

[0087] From the viewpoint of suppressing the flow of the conductive particles, the content of the component (F2) may be, for example, 0.1 to 10 parts by mass, 0.3 to 7 parts by mass, or 0.5 to 5 parts by mass per 100 parts by mass of the component (F1).

[0088] The content of the cured product of component (F) may be 1% by mass or more, 5% by mass or more, or 10% by mass or more, based on the total mass of the second adhesive layer, from the viewpoint of suppressing the flow of conductive particles. The content of the cured product of component (F) may be 50% by mass or less, 40% by mass or less, or 30% by mass or less, based on the total mass of the second adhesive layer, from the viewpoint of exhibiting low resistance in low-pressure mounting. When the content of the cured product of component (F) is within the above range, the effects of the present invention tend to be significantly exhibited. The content of component (F) in the composition or composition layer (based on the total mass of the composition or composition layer) may be the same as the above range.

[0089] [Other Components] The second adhesive layer may further contain other components. Examples of the other components include component (B) and component (C). The components (B) and (C) in the second adhesive layer and their aspects are the same as the components (B) and (C) in the first adhesive layer and their aspects.

[0090] The content of component (B) may be 1 mass % or more, 5 mass % or more, or 10 mass % or more, and may be 70 mass % or less, 50 mass % or less, or 30 mass % or less, based on the total mass of the second adhesive layer. When the second adhesive layer contains component (F), the content of component (B) in the composition or composition layer containing component (E), the thermosetting composition, and component (F) (based on the total mass of the composition or composition layer) may be the same as the above range.

[0091] The content of component (C) may be 0.1 to 10 mass % based on the total mass of the second adhesive layer. When the second adhesive layer contains component (F), the content of component (C) in the composition or composition layer containing component (E), the thermosetting composition, and component (F) (based on the total mass of the composition or composition layer) may be the same as the above range.

[0092] [Other Additives] The second adhesive layer may further contain other additives than those in the first adhesive layer. The embodiments of the other additives are the same as those in the first adhesive layer.

[0093] The thickness of the second adhesive layer may be, for example, 30.0 μm or less, 20.0 μm or less, 15.0 μm or less, 10.0 μm or less, 8.0 μm or less, 5.0 μm or less, 4.5 μm or less, 4.0 μm or less, 3.5 μm or less, or 3.0 μm or less. By having the thickness of the second adhesive layer be 30.0 μm or less, the resin content between the opposing circuits is reduced, and an increase in the connection resistance between the opposing circuits can be suppressed. This tendency is more pronounced when the thickness of the second adhesive layer is 5.0 μm or less. The thickness of the second adhesive layer may be, for example, 0.1 μm or more or 0.7 μm or more. 2 and 3, when a portion of the conductive particle 1 is exposed from the surface of the second adhesive layer 22 (for example, protruding toward the first adhesive layer 12), the distance from the surface of the second adhesive layer 22 opposite the first adhesive layer 12 to the boundary between the second adhesive layer 22 and the first adhesive layer 12 located in the space between adjacent conductive particles 1, 1 (the distance indicated by d1 in FIGS. 2 and 3) is the thickness of the second adhesive layer 22, and the exposed portion of the conductive particle 1 is not included in the thickness of the second adhesive layer 22. The length of the exposed portion of the conductive particle 1 may be, for example, 0.1 μm or more and 5.0 μm or less.

[0094] The thickness of the second adhesive layer can be determined, for example, in the same manner as in the method for measuring the thickness of the first adhesive layer described above.

[0095] The ratio of the thickness of the second adhesive layer to the average particle size of the conductive particles (thickness of the second adhesive layer / average particle size of the conductive particles) may be 0.1 or more, 0.3 or more, or 0.5 or more, from the viewpoint of making it easier for the conductive particles to be trapped between the opposing electrodes and further reducing the connection resistance. The ratio may be, for example, 2.0 or less, 1.5 or less, 1.2 or less, or 1.0 or less.

[0096] The roll of adhesive film for circuit connection according to this embodiment can improve the adhesion between the adhesive film for circuit connection unwound from the roll and circuit electrodes, etc. when they are thermocompression bonded together, and can also reduce the heating temperature during thermocompression bonding between the adhesive film for circuit connection unwound from the roll and circuit electrodes, etc.

[0097] <Method for manufacturing a roll of adhesive film for circuit connection> A method for manufacturing a roll of adhesive film for circuit connection according to this embodiment is a method for manufacturing a roll of adhesive film for circuit connection having a substrate and, provided on the substrate, a first adhesive layer containing a thermosetting composition and a second adhesive layer containing conductive particles and a thermosetting composition, the method comprising the steps of: preparing a roll of raw material; and wounding a laminate having, in this order, the first substrate, the first adhesive layer containing a thermosetting composition, the second adhesive layer containing conductive particles and a thermosetting composition, and the second substrate; and cutting the laminate unwound from the roll of raw material to a predetermined width and peeling off one of the first substrate and the second substrate, and then winding the laminate around a core to obtain a roll of adhesive film for circuit connection. In addition, in step S2, the laminate from which one of the first substrate and the second substrate has been peeled is wound only once.

[0098] In the method for producing a roll of adhesive film for circuit connection, the first substrate, the second substrate, the first adhesive layer, and the second adhesive layer may be the same as those in the roll of adhesive film for circuit connection of the present embodiment described above.

[0099] <Step S1> In step S1, a roll-shaped raw material is prepared in which a laminate (sometimes referred to as laminate A) having a first substrate, a first adhesive layer, a second adhesive layer, and a second substrate in this order is wound around a core. The roll-shaped raw material may be laminate A wound around a core with the first substrate on the outside, or laminate A wound around a core with the second substrate on the outside. The width of the roll-shaped raw material is not particularly limited, but may be 25 to 60 cm.

[0100] Step S1 may include the steps of preparing a laminate having a first adhesive layer formed on a first substrate (first preparation step), preparing a laminate having a second adhesive layer formed on a second substrate (second preparation step), bonding a laminate having a first adhesive layer formed on a first substrate and a laminate having a second adhesive layer formed on a second substrate so that the first adhesive layer and the second adhesive layer face each other to prepare a laminate A (lamination step), and winding the laminate A around a core to prepare a roll-shaped raw web (winding step). Step S1 may also include the steps of preparing a roll-shaped raw web that has been prepared in advance. Figure 4 is a perspective view showing an example of the lamination step and the winding step, and Figure 5 is an enlarged schematic cross-sectional view illustrating the steps shown in Figure 4.

[0101] [First Preparation Step] In the first preparation step, for example, a first adhesive layer is formed on a first substrate. Specifically, for example, components (A), (B), (C), and (D), as well as other components added as needed, are added to a solvent (organic solvent) and dissolved or dispersed by stirring, mixing, kneading, or the like to prepare a composition for the first adhesive layer. Thereafter, the prepared composition for the first adhesive layer is applied to the first substrate using a knife coater, roll coater, applicator, comma coater, die coater, or the like, and the solvent is then volatilized by heating to form a first adhesive layer on the first substrate. This allows for the preparation of a laminate in which a first adhesive layer is formed on the first substrate.

[0102] The solvent used in preparing the composition for the first adhesive layer may be a solvent capable of uniformly dissolving or dispersing each component. Examples of such solvents include toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, and butyl acetate. These solvents can be used alone or in combination of two or more. The stirring, mixing, and kneading of the varnish composition can be performed using, for example, a mixer, a grinder, a three-roll mill, a ball mill, a bead mill, or a homodisper.

[0103] The heating conditions for volatilizing the solvent from the composition for the first adhesive layer applied to the first substrate may be conditions that allow the solvent to volatilize sufficiently, such as, for example, 40°C or higher and 120°C or lower for 0.1 minutes or higher and 10 minutes or lower.

[0104] A portion of the solvent may remain in the first adhesive layer without being removed. The content of the solvent in such a layer may be, for example, 10% by mass or less based on the total mass of the first adhesive layer.

[0105] [Second preparation step] In the second preparation step, for example, a second adhesive layer is formed on a second substrate. Specifically, for example, the second adhesive layer is formed on the second substrate in the same manner as in the first preparation step, except that the (E), (F), (A), (B), and (C) components, and other components added as necessary, are used, thereby preparing a laminate in which the second adhesive layer is formed on the second substrate.

[0106] A portion of the solvent may remain in the second adhesive layer without being removed. The content of the solvent in the second adhesive layer may be, for example, 10 mass % or less based on the total mass of the second adhesive layer.

[0107] [Lamination Step] In the lamination step, for example, as shown in Figures 4 and 5, the laminate 10 and the laminate 20 can be laminated such that the surface of the first adhesive layer 12 opposite the first substrate 11 side in the laminate 10 having a first substrate 11 and a first adhesive layer 12 provided thereon, and the surface of the second adhesive layer 22 opposite the second substrate 21 side in the laminate 20 having a second substrate 21 and a second adhesive layer 22 provided thereon, face each other. The temperature during lamination may be, for example, 0 to 80°C. The pressure (compression pressure) during lamination may be, for example, 0.5 to 1.5 MPa. The lamination time (compression time) may be, for example, 0.5 to 1.5 seconds.

[0108] [Winding Step] In the winding step, the laminate A may be wound around a core by a known method so that the first substrate is on the outside, or so that the second substrate is on the outside. In the winding step, the winding tension of the laminate A may be, for example, 10 to 50 N / m. In Figures 4 and 5, the laminate A52 is wound around a core so that the first substrate 11 is on the outside, and a roll-shaped raw web 40 is obtained.

[0109] <Step S2> In step S2, the laminate unwound from the roll is cut to a predetermined width and one of the first substrate and the second substrate is peeled off, and then the laminate is wound around a core to obtain a roll of the adhesive film for circuit connection. The cutting to a predetermined width may include a step of dividing the roll into smaller rolls A (blocking step) and a slitting process to cut the laminate to the width of the adhesive film for circuit connection.

[0110] Examples of treatments other than those described above include an inspection step of inspecting for foreign matter, an appearance inspection, etc., and a light irradiation step of irradiating with light, etc. These treatments can be performed before peeling off one of the first substrate and the second substrate.

[0111] [Blocking Step] In the blocking step, for example, as shown in FIG. 6 , a roll-to-roll method is used to unwind the laminate A52 from a roll-shaped raw material 40, cut the laminate A52 to a predetermined width using a slit blade 92 to form the laminate A54, and then wind the laminate A54 around a core to form the wound body A42. The unwinding tension of the laminate A and the winding tension of the laminate A may be, for example, 5 to 30 N / m. The blocking step may be performed multiple times. Cutting may be performed by a known method other than using a slit blade.

[0112] In the blocking step, for example, the laminate A52 having the first substrate 11 and the second substrate 21 may be cut into a width of 10 to 30 mm or 10 to 25 mm and wound around a core to form a wound body A42.

[0113] [Inspection Step] The inspection step may include, for example, unwinding the laminate from the roll or wound body A, inspecting the laminate for foreign matter, and then winding the laminate onto a core. Examples of the method for inspecting for foreign matter include a method of visually observing for foreign matter and a method of inspecting for foreign matter using a visual inspection machine.

[0114] [Light Irradiation Step] When the second adhesive layer contains the component (F), in step S1, a laminate having the light-irradiated second adhesive layer on the second substrate may be prepared before step S1, the second adhesive layer may be irradiated with light in step S1, or step S2 may include the light irradiation step. In the light irradiation step, a cured product of the component (F) is obtained from the component (F) contained in the second adhesive layer by irradiating the second adhesive layer with light.

[0115] For light irradiation, irradiation light having a wavelength in the range of 150 to 750 nm (for example, ultraviolet light) may be used. Light irradiation can be carried out using, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a metal halide lamp, an LED light source, or the like. The cumulative light amount of the irradiated light can be set as appropriate, but is, for example, 500 to 3000 mJ / cm. ２ It may be.

[0116] Light irradiation may be performed on a laminate in which a second adhesive layer is formed on a second substrate in step S1, on a laminate unwound from a roll in step S2, or on the adhesive film for circuit connection according to the present embodiment in step S2. Light irradiation may be performed directly on the second adhesive layer, or may be performed from the second substrate side through the second substrate if the second substrate is light-transmitting, or from the first adhesive layer side through the first adhesive layer if the first adhesive layer is light-transmitting, or may be performed from the first substrate side through the first substrate and first adhesive layer if the first substrate and first adhesive layer are light-transmitting.

[0117] In step S2, a step of peeling off one of the first substrate and the second substrate (peeling step) may be performed simultaneously with or before the slitting. Fig. 7 is a perspective view showing an example of step S2. Fig. 8 is an enlarged schematic cross-sectional view for explaining the step shown in Fig. 7. In step S2 shown in Figs. 7 and 8, the second substrate 21 is peeled off from the laminate 54 unwound from the roll A42 obtained in the blocking step, and the adhesive film for circuit connection 55 from which the second substrate 21 has been peeled off is slit to a predetermined width by a rotary blade 94 to obtain a roll 100 of the adhesive film for circuit connection 56. Slitting may be performed by a known method other than using a rotary blade.

[0118] The unwinding tension and winding tension when peeling off one of the first substrate and the second substrate may be, for example, 5 to 30 N / m. The slitting may be performed by a known method.

[0119] In the slitting process, the laminate may be cut so that the width of the adhesive film for circuit connection is 0.5 to 3 mm, 0.8 to 2.0 mm, or 1.0 to 1.5 mm.

[0120] In Figures 7 and 8, after the second substrate 21 is peeled off from the laminate A54, the adhesive film for circuit connection 55 is slit to obtain the adhesive film for circuit connection 56, but it is also possible to peel off the second substrate 21 after slitting the laminate A54 to obtain the adhesive film for circuit connection 56.

[0121] 7 and 8, the adhesive film for circuit connection 56 is wound around the winding core 110 with the first substrate 11 on the outside, but the adhesive film for circuit connection 56 may also be wound around the winding core with the first substrate 11 on the inside. Also, in Figures 7 and 8, the second substrate 21 is peeled off from the laminate A54, but instead of peeling off the second substrate 21, the first substrate 11 may be peeled off to form the adhesive film for circuit connection. In this case, the adhesive film for circuit connection may be wound around the winding core with the second substrate 21 on the outside, or may be wound around the winding core with the second substrate 21 on the inside.

[0122] If the laminate before peeling off one of the first substrate and the second substrate is cut to the width of the adhesive film for circuit connection, one of the first substrate and the second substrate may be peeled off from the laminate and wound onto a winding core.

[0123] According to the method for producing a roll of an adhesive film for circuit connection according to this embodiment, in step S2, the laminate from which one of the first substrate and the second substrate has been peeled is wound only once. This prevents the condition of the adhesive layer on the side opposite the substrate from becoming too rough during the process from preparing the rolled raw material in step S1 to obtaining a roll of adhesive film for circuit connection. This prevents a decrease in the conductive particle capturing ability, allowing a roll of adhesive film for circuit connection with the desired conductive particle capturing ability to be obtained. When the second substrate is peeled in step S2, a decrease in the conductive particle capturing ability can be more effectively prevented. Furthermore, when the first substrate is peeled in step S2, a thickness of the adhesive layer of 3 μm or less can more effectively prevent a decrease in the conductive particle capturing ability.

[0124] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0125] <Preparation of Conductive Particles> Conductive particles (average particle size: 3.2 μm) were obtained by plating the surface of a plastic core with Ni and then plating the outermost surface with Pd by displacement plating.

[0126] <Preparation of thermosetting compositions for first adhesive layer and second adhesive layer> The components shown below were mixed in the amounts (parts by mass) shown in Table 1 to prepare a composition for the first adhesive layer and compositions (1) and (2) for the second adhesive layer.

[0127] Component (A): thermosetting resin component Component (A1): cationically polymerizable compound A1-1: ETERNACOLL OXBP (oxetane compound, manufactured by Ube Industries, Ltd.) A1-2: EHPE3150 (alicyclic epoxy compound, manufactured by Daicel Corporation) A1-3: CEL2021P (alicyclic epoxy compound, manufactured by Daicel Corporation) A1-4: JER1007 (epoxy compound, manufactured by Mitsubishi Chemical Corporation) Component (A2): at the initiation of thermal cationic polymerization A2: CXC-1821 (N-(p-methoxybenzyl)-N,N-dimethylanilium tetrakis(pentafluorophenyl)borate, manufactured by King Industries) Component (B): thermoplastic resin B1: FX-293 (phenoxy resin, manufactured by Nippon Steel Chemical & Material Co., Ltd.) B2: YP-70 (phenoxy resin, manufactured by Nippon Steel Chemical & Material Co., Ltd.) Component (C): coupling agent C1: SH-6040 (3-glycidoxypropyltrimethoxysilane, manufactured by Dow Corning Toray Co., Ltd.) Component (D): filler D1: ADMAFINE SE2050 (silica fine particles, manufactured by Admatechs Co., Ltd.) D2: AEROSIL R805 (silica fine particles, manufactured by Evonik Industries AG) Component (E): conductive particles E1: conductive particles prepared as described above Component (F): photocurable resin component Component (F1): radically polymerizable compound F1-1: VR-90 (bisphenol A-type epoxy (meth)acrylate (bifunctional) (vinyl ester resin), manufactured by Showa Denko K.K.) F1-2: A-1000 (polyethylene glycol diacrylate (bifunctional), manufactured by Shin-Nakamura Chemical Co., Ltd.) Component (F2): Photoradical polymerization initiator F2: Irgacure 907 (a compound having an α-aminoalkylphenone structure, manufactured by BASF)

[0128]

[0129] <Preparation of Substrate> Substrate A (thickness: 50 μm, material: white PET) and substrate B (thickness: 50 μm, material: PET) were prepared, each having the arithmetic mean height (Sa) and root mean square height (Sq) of the adhesive layer side and back surface side shown in Table 2.

[0130]

[0131] [Preparation of Roll-Shaped Raw Material A1] <Preparation of Laminate (1) (First Substrate and First Adhesive Layer Provided Thereon)> The composition for the first adhesive layer was applied to the adhesive layer side surface of the substrate A using a coating device, and then hot air dried at 60°C for 3 minutes to form a first adhesive layer (a layer made of the composition for the first adhesive layer) with a thickness of 6 µm. Here, the thickness was measured using the method for measuring the thickness of an adhesive layer described below. By the above operations, a laminate (1) having a first adhesive layer on a first substrate was obtained.

[0132] <Preparation of Laminate (2) (Second Substrate and Second Adhesive Layer Provided Thereon)> The composition (1) for the second adhesive layer was applied to the adhesive layer side surface of the substrate B using a coating device. Next, hot air drying was performed at 60°C for 3 minutes to form a layer made of the composition (1) for the second adhesive layer having a thickness (thickness after drying) of 3 µm on the second substrate. Here, the thickness was measured using the method for measuring the thickness of an adhesive layer described later. Next, a metal halide lamp was used to irradiate the layer made of the composition (1) for the second adhesive layer with an integrated light intensity of 1000 mJ / cm. ２ The composition (1) for the second adhesive layer was then cured to form a second adhesive layer. The above-described procedure yielded a laminate (2) comprising a second adhesive layer on a second substrate. The conductive particle density at this time was approximately 18,000 particles (pcs) / mm. ２ It was.

[0133] The laminate (1) and the laminate (2) were arranged with their respective adhesive layers facing each other, and were laminated together with their respective substrates using a roll laminator while being heated at 40°C. This produced a laminate A having a first substrate, a first adhesive layer, a second adhesive layer, and a second substrate in this order. The resulting laminate A1 was wound around a core with the first substrate facing outward, to obtain a roll-shaped raw material A1 having a width of 300 mm.

[0134] [Preparation of Roll-Shaped Raw Material A2] The composition (2) for the second adhesive layer was used instead of the composition (1) for the second adhesive layer, and the UV irradiation was 1000 mJ / cm ２Instead of using 2000 mJ / cm ２ A roll-shaped raw material A2 was produced in the same manner as in the production of the roll-shaped raw material A1, except that the above-mentioned step (a) was carried out.

[0135] [Preparation of a roll of adhesive film for circuit connection] (Example 1) The laminate A1 was unwound from a roll-shaped raw material A1, cut to a width of about 20 mm using roll-to-roll slitting equipment, and wound around a core with the first substrate on the outside to obtain a roll A. The obtained roll A was unwound, the second substrate was peeled off, and then cut to a width of about 2 mm using roll-to-roll slitting equipment. After cutting, it was wound around a core with the first substrate on the outside to obtain a roll of adhesive film for circuit connection.

[0136] Example 2 A roll of adhesive film for circuit connection was obtained in the same manner as in Example 1, except that the roll A2 was used instead of the roll A1.

[0137] (Comparative Example 1) The laminate A1 was unwound from the roll-shaped raw material A1, the second substrate was peeled off, and then the laminate was wound around a core with the first substrate facing outward to obtain a wound body. Next, this wound body was unwound and cut to a width of about 20 mm using roll-to-roll slitting equipment, and the laminate was wound around a core with the first substrate facing outward to obtain a wound body. The obtained wound body was unwound and cut to a width of about 2 mm using roll-to-roll slitting equipment. After cutting, the laminate was wound around a core with the first substrate facing outward to obtain a wound body of an adhesive film for circuit connection.

[0138] Comparative Example 2 A roll of adhesive film for circuit connection was obtained in the same manner as in Comparative Example 1, except that the roll A2 was used instead of the roll A1.

[0139] The adhesive films for circuit connection unwound from the rolls obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were evaluated as follows.

[0140] [Measurement of adhesive layer thickness] The adhesive film for circuit connection was sandwiched between two pieces of glass (thickness: approximately 1 mm), and 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.) was poured into the mold. The cross section was then polished using a polishing machine, and the thicknesses of the first adhesive layer and the second adhesive layers (1) and (2) were measured using a scanning electron microscope (SEM, trade name: SE-8020, manufactured by Hitachi High-Tech Science Corporation).

[0141] [Evaluation of particle capture ability] An IC chip (outer dimensions 2 mm × 20 mm, thickness 0.3 mm, bump electrode area 840 μm) with bump electrodes arranged on it was ２ A glass substrate (0.3 mm thick) with a SiN / Al film (70 μm long x 12 μm wide, 12 μm space between bump electrodes, 8 μm high) and a SiN / Al film was prepared. After aligning the bump electrodes of the IC chip with the circuit electrodes of the glass substrate, the first substrate was peeled off from the adhesive film for circuit connection, and the substrate was sandwiched between the IC chip and the circuit electrodes with the second adhesive layer facing the circuit board. The substrate was heated and pressed for 5 seconds at a measured maximum temperature of 210°C and an area-equivalent pressure of 27 MPa on the bump electrodes to obtain a circuit connection structure. Sixty bumps were selected from the electrodes of the circuit connection structure, and the number of indentations observed under a microscope was measured. The average (Ave) and standard deviation (σ) of the measured number of indentations were used to calculate the capture number (number / 840 μm) using the following formula: ２ The number of captured particles was calculated as follows: Capture number = Ave - 3σ (formula)

[0142] [Evaluation of connection characteristics] For the circuit connection structures obtained immediately after fabrication and after the reliability test in the same manner as in the evaluation of the particle capture number, the resistance value between the opposing electrodes of each circuit connection structure (between the bump electrode and the circuit electrode) was measured by a four-terminal measurement method using a multimeter MLR21 (manufactured by Kusumoto Chemical Co., Ltd.), and the connection resistance was evaluated by comparing the average values ​​of the measurements at 14 locations. The resistance value obtained immediately after fabrication was defined as the initial resistance value, and the resistance value after the reliability test was defined as the post-reliability resistance value. The reliability test was performed by storing the circuit connection structure at a temperature of 110°C and a humidity of 85% RH for 64 hours.

[0143] [Evaluation of the surface shape of the second adhesive layer of the adhesive film for circuit connection] Using a laser microscope OLS4100 (manufactured by Olympus), the second adhesive layer side of the adhesive film for circuit connection was photographed, and the surface roughness parameters of the second adhesive layer were calculated using the attached surface analysis software. The surface roughness parameters calculated were the arithmetic mean height (Sa), root mean square height (Sq), skewness (Ssk), and kurtosis (Sku). The photographs were taken at a magnification of 100x using an objective lens. In the attached surface analysis software, the cutoff wavelength during analysis was set to λs of 25 μm, and λc and λf were not set.

[0144]

[0145] As shown in Table 3, when the adhesive films for circuit connection unwound from the rolls obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were compared, the number of captured particles in Examples 1 and 2 was large, indicating that the adhesive films for circuit connection unwound from the rolls obtained in Examples 1 and 2 had excellent particle capturing properties. Furthermore, the initial resistance values ​​and post-reliability resistance values ​​in Examples 1 and 2 were small, indicating that the adhesive films for circuit connection unwound from the rolls obtained in Examples 1 and 2 had excellent connection properties. It was also confirmed that the adhesive films for circuit connection in Examples 1 and 2, in which the Sq of the surface of the second adhesive layer was in the range of 0.005 to 0.1 μm, had superior particle capturing properties compared to the adhesive films for circuit connection in Comparative Examples 1 and 2, in which the Sq of the surface of the second adhesive layer was greater than 0.1 μm.

[0146] REFERENCE SIGNS LIST 1...conductive particles, 2...adhesive component, 10...laminate having a first substrate and a first adhesive layer provided thereon, 11...first substrate, 12...first adhesive layer, 20...laminate having a second substrate and a second adhesive layer provided thereon, 21...second substrate, 22...second adhesive layer, 40...roll-shaped raw material, 42...wound body A, 52, 54...laminate A, 55, 56, 58, 60...adhesive film for circuit connection, 92...slit blade, 94...rotary blade, 100...wound body of adhesive film for circuit connection, 101...substrate, 102, 102a, 102b...adhesive layer, 110...winding core.

Claims

1. A method for producing a roll of an adhesive film for circuit connection having a substrate and, provided on the substrate, a first adhesive layer containing a thermosetting composition and a second adhesive layer containing conductive particles and a thermosetting composition, comprising: a step S1 of preparing a roll of raw material around which a laminate having, in this order, a first substrate, a first adhesive layer containing a thermosetting composition, a second adhesive layer containing conductive particles and a thermosetting composition, and a second substrate is wound; and a step S2 of cutting the laminate unwound from the roll of raw material to a predetermined width and peeling off one of the first substrate and the second substrate, and then winding the laminate around a core to obtain a roll of adhesive film for circuit connection, wherein in step S2, the laminate from which one of the first substrate and the second substrate has been peeled off is wound only once.

2. The method for producing a roll of an adhesive film for circuit connection according to claim 1, wherein the second substrate is peeled off in step S2.

3. The method for producing a roll of an adhesive film for circuit connection according to claim 1, wherein step S2 includes cutting the laminate from which one of the first substrate and the second substrate has been peeled off to a width of 0.5 to 3 mm.

4. A roll of an adhesive film for circuit connection, the adhesive film having a substrate and an adhesive layer provided on the substrate, wound around a core, the adhesive layer comprising a first adhesive layer containing a thermosetting composition and a second adhesive layer containing conductive particles and a thermosetting composition, and when the adhesive film for circuit connection is unwound from the roll, the root mean square height of the surface of the adhesive layer opposite to the substrate is 0.005 to 0.1 μm.

5. The roll according to claim 4, wherein when the adhesive film for circuit connection is unwound from the roll, the kurtosis of the surface of the adhesive layer opposite the substrate is 2.8 to 4.

6. The roll according to claim 4 or 5, wherein the second adhesive layer further contains a cured product of a photocurable resin component.

7. The roll according to claim 4 or 5, wherein the adhesive film for circuit connection has the substrate, the first adhesive layer and the second adhesive layer in this order.

8. A raw sheet for forming an adhesive film for circuit connection, comprising a laminate having a first substrate, a first adhesive layer containing a thermosetting composition, a second adhesive layer containing conductive particles and a thermosetting composition, and the second substrate in this order, and a wound body wound around a core.

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