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

Abstract

This invention provides a method for manufacturing adhesive films for circuit connections. [Solution] A method for manufacturing an adhesive film for circuit connections, comprising: preparing a substrate having a plurality of recesses on its surface, in which conductive particles are arranged in at least a portion of the plurality of recesses; transferring conductive particles to the composition layer by providing a composition layer on the surface of the substrate containing a photocurable component having radical curability and a first thermosetting component that does not have radical curability; forming a first adhesive layer containing a plurality of conductive particles, a cured product of the photocurable component and a first thermosetting component by irradiating the composition layer with light; and providing a second adhesive layer containing a second thermosetting component on one side of the first adhesive layer, wherein the photocurable component comprises a radical polymerizable compound represented by the following formula (1) and a photoradical polymerization initiator, and the first thermosetting component comprises a cationic polymerizable compound and a thermal cationic polymerization initiator. TIFF2026143512000021.tif30149

Description

[Technical Field]

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

[0002] Methods for mounting liquid crystal driver ICs onto glass panels for liquid crystal displays can be broadly classified into two types: COG (Chip-on-Glass) mounting and COF (Chip-on-Flex) mounting. In COG mounting, the liquid crystal driver IC is directly bonded to the glass panel using an adhesive containing conductive particles (e.g., circuit connection adhesive). On the other hand, in COF mounting, the liquid crystal driver IC is bonded to a flexible tape with metal wiring, and then these are bonded to the glass panel using an adhesive containing conductive particles (e.g., circuit connection adhesive).

[0003] Incidentally, with the recent increase in the resolution of liquid crystal displays, the metal bumps that serve as circuit electrodes for liquid crystal driving ICs have become narrower in pitch and area. As a result, conductive particles in the adhesive may flow out between adjacent circuit electrodes, potentially causing a short circuit. This tendency is particularly pronounced in COG (Center of Grain) mounting. When conductive particles flow out between adjacent circuit electrodes, the number of conductive particles trapped between the metal bump and the glass panel decreases, which can lead to connection failures due to increased connection resistance between opposing circuit electrodes.

[0004] To solve these problems, a method has been proposed in which multiple insulating particles (child particles) are attached to the surface of a conductive particle (mother particle) to form a composite particle (insulating coated conductive particle). For example, Patent Document 1 proposes a method in which spherical resin particles are attached to the surface of a conductive particle. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 4773685 [Overview of the project] Problems to be Solved by the Invention

[0006] In order to solve the above-described problems without using the above-mentioned insulating-coated conductive particles, the present inventors have been studying manufacturing an adhesive film for circuit connection by a method in which, after disposing conductive particles in recesses of a base having the recesses formed in advance, an adhesive layer is provided on the surface of the base where the recesses are formed, and then the conductive particles are transferred to the adhesive layer. According to this method, the conductive particles can be arranged in a spaced-apart manner in predetermined regions within the film. Therefore, for example, by manufacturing the adhesive film for circuit connection using a base having a recess pattern corresponding to the pattern of electrodes (circuit pattern) to be connected, the positions and number of conductive particles in the adhesive film for circuit connection can be sufficiently controlled.

[0007] However, in the above method, in order to transfer the conductive particles to the adhesive layer, the adhesive layer needs to have appropriate fluidity. Therefore, in the adhesive film for circuit connection obtained by the above method, during connection, the resin constituting the adhesive layer flows, and the conductive particles also flow at the same time, which may cause the conductive particles to be excluded from between opposing circuit electrodes. It is also conceivable to suppress the flow of conductive particles by curing the adhesive layer after transferring the conductive particles to the adhesive layer, but in this case, the resin present between the electrodes and the conductive particles becomes difficult to remove during connection, which tends to cause a problem of increased connection resistance.

[0008] Therefore, the main object of the present invention is to provide a method for manufacturing an adhesive film for circuit connection, which can improve the capture rate of conductive particles between opposing circuit electrodes while sufficiently controlling the position and number of the conductive particles, and can sufficiently ensure conduction between the electrodes. Means for Solving the Problems

[0009] One aspect of the present invention relates to a method for producing an adhesive film for circuit connection shown in the following [1] to

[18] .

[0010] [1] A method for producing an adhesive film for circuit connection, comprising: preparing a substrate having a plurality of recesses on a surface thereof, wherein conductive particles are arranged in at least a part of the plurality of recesses; transferring the conductive particles to a composition layer by providing the composition layer containing a photocurable component and a first thermosetting component on the surface of the substrate; forming a first adhesive layer containing the plurality of conductive particles, a cured product of the photocurable component and the first thermosetting component by irradiating the composition layer with light; and providing a second adhesive layer containing a second thermosetting component on one surface of the first adhesive layer.

[0011] [2] The method for producing an adhesive film for circuit connection according to [1], wherein the photocurable component contains a radically polymerizable compound and a photoradical polymerization initiator, and the first thermosetting component contains a cationically polymerizable compound and a thermal cationic polymerization initiator.

[0012] [3] The method for producing an adhesive film for circuit connection according to [2], wherein the first thermosetting component contains a compound having a cyclic ether group as the cationically polymerizable compound.

[0013] [4] The method for producing an adhesive film for circuit connection according to [3], wherein the first thermosetting component contains at least one selected from the group consisting of oxetane compounds and alicyclic epoxy compounds as the cationically polymerizable compound.

[0014] [5] The method for producing an adhesive film for circuit connection according to any one of [2] to [4], wherein the photocurable component contains a compound represented by the following formula (1) as the radically polymerizable compound.

Chemical Formula

[0015] [6] The method for producing an adhesive film for circuit connection according to any one of [2] to [5], wherein said photocurable component contains a compound represented by the following formula (I) as said photo-radical polymerization initiator.

Chemical Formula

[0016] [7] The method for producing an adhesive film for circuit connection according to any one of [2] to [6], wherein said first thermosetting component contains a salt compound having a cation represented by the following formula (II) or the following formula (III) as said thermal cationic polymerization initiator.

Chemical Formula

Chemical Formula

[0017] [8] The method for producing an adhesive film for circuit connection according to any one of [1] to [7], wherein the average particle diameter of the conductive particles is 1 to 30 µm, and the C.V. value of the particle diameter of the conductive particles is 20% or less.

[0018] [9] The method for producing an adhesive film for circuit connection according to any one of [1] to [8], wherein the conductive particles are solder particles.

[0019]

[10] The method for producing an adhesive film for circuit connection according to [9], wherein the solder particles comprise at least one selected from the group consisting of tin, tin alloys, indium and indium alloys.

[0020]

[11] The method for producing an adhesive film for circuit connection according to

[10] , wherein the solder particles comprise at least one selected from the group consisting of In-Bi alloys, In-Sn alloys, In-Sn-Ag alloys, Sn-Au alloys, Sn-Bi alloys, Sn-Bi-Ag alloys, Sn-Ag-Cu alloys and Sn-Cu alloys.

[0021]

[12] The method for producing an adhesive film for circuit connection according to any one of [9] to

[11] , wherein the solder particles have a flat portion on a part of the surface thereof.

[0022]

[13] The method for producing an adhesive film for circuit connection according to

[12] , wherein the ratio (B / A) of the diameter B of the flat portion to the diameter A of the solder particle satisfies the following formula. 0.01 < B / A < 1.0

[0023]

[14] The method for producing an adhesive film for circuit connection according to any one of [1] to

[13] , wherein when a rectangle circumscribing the projected image of the conductive particle is formed by two pairs of parallel lines, and the distances between opposite sides are defined as X and Y (with Y < X), X and Y satisfy the following formula. 0.8 < Y / X ≦ 1.0

[0024]

[15] The method for producing an adhesive film for circuit connection according to any one of [1] to

[14] , wherein the plurality of recesses are formed in a predetermined pattern.

[0025] In the above-described method of manufacturing the side, a composition containing a photocurable component and a thermosetting component is used, conductive particles are transferred to a layer made of the composition (composition layer), and then the composition is photocured. Therefore, resin flow during connection can be suppressed without impairing transferability. Thus, according to the above-described method of manufacturing the side, a circuit connection adhesive film can be obtained that can improve the capture rate of conductive particles between opposing circuit electrodes while sufficiently controlling the position and number of conductive particles in the circuit connection adhesive film. Furthermore, the above-described method of manufacturing the side can ensure sufficient conductivity between electrodes. This is presumed to be because, by using a combination of a photocurable component and a thermosetting component, the thermosetting component can be incorporated into the photocured layer (first adhesive layer) of the composition layer, and the photocured layer can be given resin fluidity to the extent that conductive particles are not excluded during connection. Therefore, problems such as increased connection resistance due to the resin present between the electrode and the conductive particles being difficult to exclude during connection are suppressed.

[0026] Another aspect of the present invention relates to the circuit connection adhesive film shown below

[16] .

[0027]

[16] A circuit connection adhesive film containing conductive particles, comprising: a first adhesive layer containing a plurality of conductive particles, a cured product of a photocurable component, and a first thermosetting component; and a second adhesive layer provided on the first adhesive layer and containing a second thermosetting component, wherein at least a portion of the plurality of conductive particles are arranged in a predetermined pattern in a plan view of the circuit connection adhesive film, and adjacent conductive particles are arranged laterally separated from each other in a longitudinal cross-section of the circuit connection adhesive film.

[0028] Another aspect of the present invention relates to the connection structure shown below

[17] .

[0029]

[17] A connection structure comprising a first circuit member having a first electrode, a second circuit member having a second electrode, and a cured body of the circuit connection adhesive film described in

[16] , the first electrode and the second electrode being electrically connected to each other via the conductive particles and the first circuit member and the second circuit member being bonded together.

[0030] Another aspect of the present invention relates to a method for manufacturing a connecting structure as shown in

[18] below.

[0031]

[18] A method for manufacturing a connection structure, comprising: placing the circuit connection adhesive film described in

[16] between the surface of a first circuit member having a first electrode and the surface of a second circuit member having a second electrode and the second electrode being provided; and heating a laminate including the first circuit member, the circuit connection adhesive film and the second circuit member while pressing it in the thickness direction of the laminate to electrically connect the first electrode and the second electrode to each other via the conductive particles and bond the first circuit member and the second circuit member. [Effects of the Invention]

[0032] According to the present invention, it is possible to provide a method for manufacturing a circuit connection adhesive film that can improve the capture rate of conductive particles between opposing circuit electrodes while sufficiently controlling the position and number of conductive particles, and that can sufficiently ensure conductivity between electrodes. [Brief explanation of the drawing]

[0033] [Figure 1] Figure 1 is a schematic cross-sectional view showing one embodiment of an adhesive film for circuit connection. [Figure 2] Figure 2 is a schematic plan view showing an example of the arrangement of conductive particles in the circuit connection adhesive film shown in Figure 1. [Figure 3] Figure 3 is a schematic plan view showing an example of the arrangement of conductive particles in the circuit connection adhesive film shown in Figure 1. [Figure 4]Figure 4 is a schematic cross-sectional view showing another embodiment of the adhesive film for circuit connections. [Figure 5] Figure 5 is a schematic cross-sectional view of the substrate used in the manufacture of the circuit connection adhesive film shown in Figure 1. [Figure 6] Figure 6 shows a modified example of the cross-sectional shape of the recess in the substrate shown in Figure 5. [Figure 7] Figure 7 shows the state in which conductive particles are arranged in the recesses of the substrate shown in Figure 5. [Figure 8] Figure 8 is a schematic cross-sectional view showing one step in the manufacturing method of an adhesive film for circuit connections according to one embodiment. [Figure 9] Figure 9 is a schematic cross-sectional view showing one step in the manufacturing method of the circuit connection adhesive film shown in Figure 1. [Figure 10] Figure 10 is a schematic cross-sectional view showing one step in the manufacturing method of the circuit connection adhesive film shown in Figure 1. [Figure 11] Figure 11 is a schematic cross-sectional view showing one embodiment of the connection structure. [Figure 12] Figure 12 is a schematic cross-sectional view showing one embodiment of a method for manufacturing a connecting structure. [Modes for carrying out the invention]

[0034] Embodiments of the present invention will be described below. However, the present invention is not limited to the following embodiments. Unless otherwise specified, the materials exemplified below may be used individually or in combination of two or more. The content of each component in the composition means the total amount of multiple substances present in the composition if there are multiple substances corresponding to each component in the composition, unless otherwise specified. Numerical ranges indicated using "~" indicate a range that includes the numbers written before and after "~" as the minimum and maximum values, respectively. In numerical ranges described stepwise in this specification, the upper or lower limit of a numerical range in one step may be replaced with the upper or lower limit of a numerical range in another step. In numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with the values ​​shown in the examples. 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".

[0035] <Adhesive film for circuit connections> Figure 1 is a schematic diagram showing a longitudinal section of a circuit connection adhesive film according to one embodiment. The circuit connection adhesive film 10A shown in Figure 1 is a film-like adhesive (adhesive film) comprising a plurality of conductive particles 4, a first adhesive layer 1 containing an adhesive component 3 including a cured product of a photocurable component and a first thermosetting component, and a second adhesive layer 2 provided on the first adhesive layer 1 and containing a second thermosetting component. In this specification, "longitudinal section" means a cross section (cross section in the thickness direction) that is substantially perpendicular to the main surface (for example, the main surface of the circuit connection adhesive film 10A). The first thermosetting component and the second thermosetting component mean the thermosetting components contained in the first adhesive layer and the second adhesive layer, respectively.

[0036] At least some of the multiple conductive particles 4 are arranged laterally in a longitudinal cross-section of the circuit connection adhesive film 10A, with adjacent conductive particles separated from each other. In other words, the circuit connection adhesive film 10A is composed of a central region 10a in its longitudinal cross-section where conductive particles 4 are arranged laterally in a separated state from adjacent conductive particles, and surface regions 10b and 10c where conductive particles 4 are not present. Here, "lateral direction" means a direction approximately parallel to the main surface of the circuit connection adhesive film (left-right direction in Figure 1). The fact that adjacent conductive particles are arranged laterally with separation from each other can be confirmed, for example, by observing the longitudinal cross-section of the circuit connection adhesive film with a scanning electron microscope. Note that in Figure 1, some of the conductive particles 4 are exposed from the surface of the first adhesive layer 1 (for example, protruding towards the second adhesive layer 2), but the entire conductive particles 4 may be embedded in the first adhesive layer 1 so that the conductive particles 4 are not exposed from the surface of the first adhesive layer 1.

[0037] Figures 2 and 3 are schematic plan views showing examples of the arrangement of conductive particles 4 in a circuit connection adhesive film 10A. As shown in Figures 2 and 3, at least some of the multiple conductive particles 4 are arranged in a predetermined pattern in a plan view of the circuit connection adhesive film. In Figure 2, in a plan view of the circuit connection adhesive film, the conductive particles 4 are arranged at regular and approximately equal intervals over the entire area of ​​the circuit connection adhesive film 10A. However, as shown in Figure 3, for example, the conductive particles 4 may be arranged such that, in a plan view of the circuit connection adhesive film, regions 10d where multiple conductive particles 4 are regularly arranged and regions 10e where conductive particles 4 are absent are regularly formed. The position and number of conductive particles 4 can be set according to, for example, the shape, size, and pattern of the electrodes to be connected. The fact that at least some of the multiple conductive particles are arranged in a predetermined pattern can be confirmed, for example, by observing the circuit connection adhesive film from above its main surface using an electron microscope.

[0038] (First adhesive layer) The first adhesive layer 1 contains conductive particles 4 (hereinafter sometimes referred to as "component (A)"), a cured product of a photocurable component (hereinafter sometimes referred to as "component (B)"), and a first thermosetting component (hereinafter sometimes referred to as "component (C)"). The cured product of component (B) may be a cured product in which component (B) has been completely cured, or a cured product in which a portion of component (B) has been cured. Component (C) is a component that can flow at the time of connection, and is, for example, an uncured curable component (e.g., a resin component). The components other than the conductive particles 4 that constitute the first adhesive layer 1 are, for example, components that do not have conductivity (e.g., an insulating resin component).

[0039] [(A) Component: Conductive particles] Component (A) is not particularly limited as long as it is a conductive particle, and may be metal particles composed of metals such as Au, Ag, Pd, Ni, Cu, or solder, or conductive carbon particles composed of conductive carbon. Component (A) may also be a coated conductive particle comprising a core containing non-conductive glass, ceramic, or plastic (such as polystyrene), and a coating layer containing the above-mentioned metal or conductive carbon that covers the core. Component (A) can be used with one type of conductive particle alone or in combination of two or more types of conductive particles.

[0040] When coated conductive particles are used as component (A), the cured product of the thermosetting component can be easily deformed by heating or pressurizing, thereby increasing the contact area between the electrodes and component (A) when electrically connecting the electrodes, and further improving the conductivity between the electrodes.

[0041] When metal particles formed from a heat-meltable metal are used as component (A), the connection between electrodes tends to become stronger. This tendency is particularly pronounced when solder particles are used as component (A).

[0042] The solder particles may contain at least one selected from the group consisting of tin, tin alloys, indium, and indium alloys, from the viewpoint of achieving both connection strength and a low melting point.

[0043] Examples of tin alloys that can be used include In-Sn alloy, In-Sn-Ag alloy, Sn-Au alloy, Sn-Bi alloy, Sn-Bi-Ag alloy, Sn-Ag-Cu alloy, and Sn-Cu alloy. Specific examples of these tin alloys are listed below. ·In-Sn (In52 mass%, Sn48 mass%, melting point 118℃) ·In-Sn-Ag (In20% by mass, Sn77.2% by mass, Ag2.8% by mass, melting point 175℃) • Sn-Bi (Sn 43% by mass, Bi 57% by mass, melting point 138°C) • Sn-Bi-Ag (Sn 42% by mass, Bi 57% by mass, Ag 1% by mass; melting point 139°C) ·Sn-Ag-Cu (Sn96.5% by mass, Ag3% by mass, Cu0.5% by mass, melting point 217℃) • Sn-Cu (Sn 99.3% by mass, Cu 0.7% by mass, melting point 227°C) ·Sn-Au (Sn21.0% by mass, Au79.0% by mass, melting point 278℃)

[0044] Examples of indium alloys that can be used include In-Bi alloys and In-Ag alloys. Specific examples of these indium alloys are listed below. In-Bi (In 66.3% by mass, Bi 33.7% by mass, melting point 72°C) In-Bi (In 33.0% by mass, Bi 67.0% by mass, melting point 109°C) In-Ag (In 97.0% by mass, Ag 3.0% by mass, melting point 145℃) Furthermore, the indium alloy containing tin mentioned above shall be classified as a tin alloy.

[0045] From the viewpoint of obtaining higher reliability during high-temperature, high-humidity testing and thermal shock testing, the solder particles may include at least one selected from the group consisting of In-Bi alloy, In-Sn alloy, In-Sn-Ag alloy, Sn-Au alloy, Sn-Bi alloy, Sn-Bi-Ag alloy, Sn-Ag-Cu alloy, and Sn-Cu alloy.

[0046] The tin alloy or indium alloy mentioned above may be selected depending on the application of the solder particles (temperature during use), etc. For example, when using solder particles for fusion at low temperatures, if In-Sn alloy or Sn-Bi alloy is used, fusion can be achieved at temperatures below 150°C. If materials with high melting points, such as Sn-Ag-Cu alloy or Sn-Cu alloy, are used, high reliability can be maintained even after being left at high temperatures.

[0047] The solder particles may contain one or more elements selected from Ag, Cu, Ni, Bi, Zn, Pd, Pb, Au, P, and B. When the solder particles contain Ag or Cu, the melting point of the solder particles can be lowered to about 220°C, and the bonding strength with the electrodes is further improved, making it easier to obtain better conductivity reliability.

[0048] The Cu content of the solder particles is, for example, 0.05 to 10 mass%, and may be 0.1 to 5 mass% or 0.2 to 3 mass%. A Cu content of 0.05 mass% or more makes it easier to achieve better solder connection reliability. Furthermore, a Cu content of 10 mass% or less tends to result in solder particles with a low melting point and excellent wettability, which in turn tends to improve the connection reliability of the joint formed by the solder particles.

[0049] The Ag content of the solder particles is, for example, 0.05 to 10 mass%, and may be 0.1 to 5 mass% or 0.2 to 3 mass%. When the Ag content is 0.05 mass% or higher, it is easier to achieve better solder connection reliability. Furthermore, when the Ag content is 10 mass% or lower, the solder particles tend to have a low melting point and excellent wettability, resulting in better connection reliability at the joint formed by the solder particles.

[0050] Solder particles may have a flat portion on part of their surface. When using such solder particles, the flat portion of the solder particle comes into contact with the electrode, ensuring a large contact area between the flat portion and the electrode. Furthermore, when connecting an electrode made of a material that solder easily wets and spreads easily with an electrode made of a material that solder does not easily wet and spread easily, the connection between the two electrodes can be made favorably by adjusting the position of the flat portion of the solder particle on the side of the latter electrode. The surface of the solder particle other than the flat portion may be spherical. That is, the solder particle may have a flat portion and a spherical curved portion. Specifically, the solder particle may have a shape in which a flat portion with diameter B is formed on part of the surface of a sphere with diameter A. When using such solder particles, better conductivity and insulation reliability are easily obtained.

[0051] When a solder particle has a shape in which a flat portion with diameter B is formed on a part of the surface of a sphere with diameter A, from the viewpoint of achieving better conductivity and insulation reliability, the ratio of the diameter B of the flat portion to the diameter A of the solder particle (B / A) should be, for example, greater than 0.01 and less than 1.0 (0.01

[0052] ​When a rectangle circumscribing a projected image of a conductive particle is formed by two pairs of parallel lines, if the distances between opposing sides are defined as X and Y respectively (with Y<X), the ratio of Y to X (Y / X) may be more than 0.8 and 1.0 or less (0.8<Y / X≦1.0). Such conductive particles can be said to be particles closer to a true sphere. When the conductive particles have a shape close to a true sphere, solder particles tend to be easily accommodated in the recesses of a substrate in the manufacturing method described later. Furthermore, when solder particles are used among conductive particles, since the solder particles have a shape close to a true sphere, when a plurality of opposing electrodes are electrically connected via solder, uneven contact between the solder particles and the electrodes is less likely to occur, and a stable connection tends to be obtained. The ratio of Y to X (Y / X) may be more than 0.8 and less than 1.0 (0.8<Y / X<1.0), and may also be 0.81 to 0.99. The projected image of a conductive particle can be obtained, for example, by observing an arbitrary conductive particle with a scanning electron microscope. When obtaining Y / X, two pairs of parallel lines are drawn on the obtained projected image, one pair of parallel lines is arranged at the position where the distance between the parallel lines is minimized, and the other pair of parallel lines is arranged at the position where the distance between the parallel lines is maximized. This operation is performed on 300 conductive particles to calculate the average value of Y / X, and this average value is defined as Y / X of the conductive particles.

[0053] Component (A) may be an insulation-coated conductive particle comprising the above metal particles, conductive carbon particles or coated conductive particles, and an insulating layer made of an insulating material such as resin that coats the surface of the particle. When component (A) is an insulation-coated conductive particle, even when the content of component (A) is high, since the particle surface is provided with an insulating layer, the occurrence of short circuits caused by contact between components (A) can be suppressed, and the insulation between adjacent electrode circuits can also be improved.

[0054] The average particle diameter of component (A) may be 1 µm or more, 2 µm or more, or 4 µm or more from the viewpoint of easily obtaining excellent conductivity. The average particle diameter of component (A) may be 30 µm or less, 25 µm or less, or 20 µm or less from the viewpoint of easily obtaining better connection reliability for micro-sized electrodes. From these viewpoints, the average particle diameter of component (A) may be 1 to 30 µm, 2 to 25 µm, or 4 to 20 µm.

[0055] The average particle size of component (A) can be measured using various methods appropriate to the size. For example, methods such as dynamic light scattering, laser diffraction, centrifugal sedimentation, electrical detection band method, and resonant mass spectrometry can be used. Furthermore, methods for measuring particle size from images obtained by optical microscopes, electron microscopes, etc., can be used. Specific examples of equipment include flow-type particle image analyzers, microtrac, and Coulter counters. Note that the particle size of component (A), which is not perfectly spherical, may be the diameter of the circle circumscribing the conductive particle in the SEM image.

[0056] (A) The CV value of the particle size of component (A) may be 20% or less, 10% or less, 7% or less, or 5% or less, from the viewpoint of achieving better conductivity and insulation reliability. The lower limit of the CV value of the particle size of component (A) is not particularly limited and may be, for example, 0.1% or more, 1% or more, or 2% or more.

[0057] The CV value of the particle size of component (A) is calculated by multiplying the value obtained by dividing the standard deviation of the particle size of the conductive particles by the average particle size by 100. The standard deviation of the particle size of the conductive particles can be measured using the same method as the method for measuring the average particle size of the conductive particles described above.

[0058] Component (A) may be conductive particles having an average particle diameter of 1 to 30 μm and a particle diameter CV value of 20% or less. Such conductive particles have both a small average particle diameter and a narrow particle size distribution, and can be suitably used as conductive particles for anisotropic conductive materials with high conductivity and insulation reliability.

[0059] (A) The content of component (A) may be, for example, 1% by mass or more, 5% by mass or more, or 10% by mass or more, based on the total mass of the first adhesive layer, from the viewpoint of further improving conductivity. (A) The content of component (A) may be, for example, 80% by mass or less, 70% by mass or less, or 60% by mass or less, based on the total mass of the first adhesive layer, from the viewpoint of easily suppressing short circuits. From these viewpoints, the content of component (A) may be, for example, 1 to 80% by mass, 5 to 70% by mass or 10 to 60% by mass, based on the total mass of the first adhesive layer.

[0060] The particle density of component (A) in the first adhesive layer 1 is set to 100 particles / mm² from the viewpoint of obtaining stable connection resistance. 2 More than 1000 pieces / mm 2 More than 3000 pieces / mm 2 More than or equal to 5000 pieces / mm 2 The above is acceptable. The particle density of component (A) in the first adhesive layer 1 is 100,000 particles / mm² from the viewpoint of improving the insulation between adjacent electrodes. 2 Below, 70000 pieces / mm 2 Below, 50000 pieces / mm 2 The following or 30,000 pieces / mm 2 The following is acceptable:

[0061] [Component (B): Photocurable component] Component (B) is not particularly limited as long as it is a component that hardens by light irradiation (e.g., a resin component), but from the viewpoint of having better connection resistance, it may be a component that has radical curability. Component (B) may include, for example, a radical polymerizable compound (hereinafter sometimes referred to as "component (B1)") and a photoradical polymerization initiator (hereinafter sometimes referred to as "component (B2)"). Component (B) may be a component consisting of component (B1) and component (B2).

[0062] (B1) Component: Radical polymerizable compound Component (B1) is a compound having polymerizable groups that react with radicals (radical polymerizable groups) (radical polymerizable compound). Examples of radical polymerizable groups include (meth)acryloyl groups, vinyl groups, allyl groups, styryl groups, alkenyl groups, alkenylene groups, maleimide groups, etc. The number of radical polymerizable groups (number of functional groups) in component (B1) may be 2 or more from the viewpoint of easily obtaining the desired melt viscosity after polymerization, further improving the effect of reducing connection resistance, and providing superior connection reliability, and may be 10 or less from the viewpoint of suppressing curing shrinkage during polymerization. Furthermore, in order to balance the crosslinking density and curing shrinkage, in addition to compounds with a number of radical polymerizable groups within the above range, compounds with a number of radical polymerizable groups outside the above range may also be used.

[0063] Component (B1) may, for example, contain a polyfunctional (two- or more functional) (meth)acrylate from the viewpoint of suppressing the flow of conductive particles. The polyfunctional (two- or more functional) (meth)acrylate may be a bifunctional (meth)acrylate, and the bifunctional (meth)acrylate may be a bifunctional aromatic (meth)acrylate.

[0064] 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, Meth)acrylate, ethoxylated polypropylene glycol di(meth)acrylate, 1,3-butanediol 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, ethoxylated 2-methyl-1,3-propanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, ethoxylated propoxylated trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethoxylated pentaerythritol tri(meth)acrylate Aliphatic (meth)acrylates such as 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, ditrimethylolpropanetetraacrylate, and dipentaerythritol hexa(meth)acrylate;Ethoxylated bisphenol A type di(meth)acrylate, propoxylated bisphenol A type di(meth)acrylate, ethoxylated propoxylated bisphenol A type di(meth)acrylate, ethoxylated bisphenol F type di(meth)acrylate, propoxylated bisphenol F type di(meth)acrylate, ethoxylated propoxylated bisphenol F type di(meth)acrylate, ethoxylated fluorene type di(meth)acrylate (e.g., 9,9-bi[4-(2-acryloyloxyethoxy)phenyl]fluor Examples include aromatic (meth)acrylates such as olene, propoxylated fluorene-type di(meth)acrylate, and ethoxylated propoxylated fluorene-type di(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; and isocyanurate (meth)acrylates such as caprolactone-modified tris-(2-acryloxyethyl) isocyanurate.

[0065] The content of polyfunctional (two or more functional) (meth)acrylate may be, for example, 40-100% by mass, 50-100% by mass, or 60-100% by mass, based on the total mass of component (B1), from the viewpoint of achieving both a reduction in connection resistance and suppression of particle flow.

[0066] Component (B1) may further contain monofunctional (meth)acrylates in addition to polyfunctional (bifunctional or more) (meth)acrylates. Examples of monofunctional (meth)acrylates 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, nonyl (meth)acrylate, decyl (meth)acrylate. )Acrylates such as 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)acryloyloxyethyl) succinate, etc. Aliphatic (meth)acrylates; 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, phenoxypolyethylene glycol (meth)acrylate Aromatic (meth)acrylates such as nonylphenoxypolyethylene glycol (meth)acrylate, phenoxypolypropylene 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, 2-hydroxy-3-(2-naphthoxy)propyl (meth)acrylate, bisphenol A type epoxy (meth)acrylate, etc.Examples include (meth)acrylates having epoxy groups such as glycidyl (meth)acrylate, (meth)acrylates having alicyclic epoxy groups such as 3,4-epoxycyclohexylmethyl (meth)acrylate, and (meth)acrylates having oxetanyl groups such as (3-ethyloxetan-3-yl)methyl (meth)acrylate.

[0067] The content of monofunctional (meth)acrylate may be, for example, 0 to 60% by mass, 0 to 50% by mass, or 0 to 40% by mass, based on the total mass of component (B1).

[0068] The cured product of component (B) may have polymerizable groups that react with a factor other than a radical. The polymerizable groups that react with a factor other than a radical may be cationic polymerizable groups that react with a cation. Examples of cationic polymerizable groups 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 (B) having polymerizable groups that react with a factor other than a radical can be introduced by using a (meth)acrylate having polymerizable groups that react with a factor other than a radical, such as an epoxy group (meth)acrylate, an alicyclic epoxy group (meth)acrylate, or an oxetanyl group (meth)acrylate, as component (B).

[0069] As a (meth)acrylate having polymerizable groups that react with means other than radicals, a compound represented by the following formula (1) may be used, in terms of crosslinking the radical polymerizable compound with the thermosetting component described later to form a stronger connection during connection. [ka]

[0070] In formula (1), R 1represents a hydrogen atom or a methyl group, and X represents an alkanediyl group having 1 to 3 carbon atoms. Examples of alkanediyl groups having 1 to 3 carbon atoms include a methylene group, an ethylene group, and a propylene group. A specific example of the compound represented by the above formula (1) is 3,4-epoxycyclohexylmethyl (meth)acrylate.

[0071] Radical polymerizable compounds having polymerizable groups that react with means other than radicals (e.g., (meth)acrylate) may be used in combination with radical polymerizable compounds that do not have polymerizable groups that react with means other than radicals (e.g., (meth)acrylate) from the viewpoint of suppressing curing shrinkage during polymerization. The mass ratio of the radical polymerizable compound having polymerizable groups that react with means other than radicals to the total mass of component (B1) (mass of radical polymerizable compound having polymerizable groups that react with means other than radicals (amount charged) / total mass of component (B1) (amount charged)) may be, for example, 0 or more, 0.1 or more, 0.2 or more or 0.3 or more, 0.7 or less, 0.6 or less, 0.5 or less or 0.4 or less, 0 to 0.7, 0.1 to 0.6, 0.2 to 0.5 or 0.3 to 0.4 from the viewpoint of improving reliability. From the viewpoint of further suppressing curing shrinkage during polymerization, the mass ratio of (meth)acrylate having polymerizable groups that react with non-radicals to (meth)acrylate that does not have polymerizable groups that react with non-radicals may be within the above range.

[0072] Component (B1) may contain polyfunctional (two or more functional) and monofunctional (meth)acrylates, as well as other radical polymerizable compounds. Examples of other radical polymerizable compounds include maleimide compounds, vinyl ether compounds, allyl compounds, styrene derivatives, acrylamide derivatives, nadiimide derivatives, and the like. The content of other radical polymerizable compounds may be, for example, 0 to 40% by mass based on the total mass of component (B1).

[0073] (B2) Component: Photoradical polymerization initiator Component (B2) is a photopolymerization initiator (photolatent radical generator) that generates radicals upon irradiation with light containing wavelengths in the range of 150 to 750 nm, preferably light containing wavelengths in the range of 254 to 405 nm, and more preferably light containing a wavelength of 365 nm (e.g., ultraviolet light). Component (B2) may be used alone or in combination of multiple components.

[0074] Component (B2) decomposes upon exposure to light, generating free radicals. In other words, component (B2) is a compound that generates radicals upon application of external light energy. Component (B2) may be a compound having structures such as an oxime ester structure, bisimidazole structure, acridine structure, α-aminoalkylphenone structure, aminobenzophenone structure, N-phenylglycine structure, acylphosphine oxide structure, benzyldimethyl ketal structure, or α-hydroxyalkylphenone structure. Component (B2) may be used alone or in combination of multiple components.

[0075] Component (B2) may be a compound having an oxime ester structure, from the viewpoint of further suppressing the flow of conductive particles and further improving the capture rate, and from the viewpoint of further suppressing delamination after connection and further suppressing the increase in connection resistance. From a similar viewpoint, the compound having an oxime ester structure may be a compound represented by the following formula (I). [ka]

[0076] In formula (I), R 2 , R 3 and R 4 Each of these independently represents an organic group containing a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aromatic hydrocarbon group.

[0077] Specific examples of compounds 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)], etanone,1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(o-acetyloxime), and others. When using such highly active oxime ester-based photoradical polymerization initiators, crosslinking can be sufficiently advanced even when the amount of component (B1) is small.

[0078] The content of component (B2) 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 component (B1), from the viewpoint of suppressing the flow of conductive particles.

[0079] From the viewpoint of suppressing the flow of conductive particles, the content of cured component (B) may be, for example, 1 part by mass or more, 5 parts by mass or more, or 10 parts by mass or more, per 100 parts by mass of the total amount of components other than component (A) in the first adhesive layer. From the viewpoint of exhibiting low resistance in low-pressure mounting, the content of cured component (B) may be, for example, 30 parts by mass or less, 25 parts by mass or less, or 20 parts by mass or less, per 100 parts by mass of the total amount of components other than component (A) in the first adhesive layer. From these viewpoints, the content of cured component (B) may be, for example, 1 to 30 parts by mass, 5 to 25 parts by mass, or 10 to 20 parts by mass, per 100 parts by mass of the total amount of components other than component (A) in the first adhesive layer. The content of component (B) in the composition or composition layer for forming the first adhesive layer (based on the total mass of the composition or composition layer) may be the same as the above range.

[0080] [(C) component: thermosetting component] Component (C) is not particularly limited as long as it is a heat-curing component (e.g., a resin component). However, if component (B) is a radical-curable component, component (C) may be a non-radical-curable component from the viewpoint of storage stability, etc. If both component (B) and component (C) are radical-curable components, there is a possibility that the thermosetting component may harden due to radicals remaining in the first adhesive layer during storage. Examples of non-radical-curable components include cationic-curable components (e.g., cationic polymerizable compounds and thermal cationic polymerization initiators) and anionic-curable components (anionic polymerizable compounds and thermal anionic polymerization initiators).

[0081] Component (C) may be a component having cationic curability, in terms of superior connection resistance, and may include, for example, a cationic polymerizable compound (hereinafter sometimes referred to as "component (C1)") and a thermal cationic polymerization initiator (hereinafter sometimes referred to as "component (C2)"). Component (C) may consist only of components (C1) and (C2).

[0082] (C1) Component: Cationic polymerizable compound Component (C1) is a compound that crosslinks by reacting with component (C2) upon heat. Note that component (C1) refers to a compound that does not have radical polymerizable groups, and component (C1) is not included in component (B1). Component (C1) may be used alone or in combination of multiple components.

[0083] Component (C1) may be a compound having a cyclic ether group, from the viewpoint of further improving the effect of reducing connection resistance and providing superior connection reliability. Among compounds having a cyclic ether group, when at least one selected from the group consisting of oxetane compounds and alicyclic epoxy compounds is used, the effect of reducing connection resistance tends to be further improved. Component (C1) may contain both at least one oxetane compound and at least one alicyclic epoxy compound, from the viewpoint of easily obtaining the desired melt viscosity.

[0084] The oxetane compound used as component (C1) is not particularly limited as long as it has an oxetanyl group and does not have a radical polymerizable group. Examples of 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 individually or in combination.

[0085] The alicyclic epoxy compound used as component (C1) is not particularly limited as long as it has an alicyclic epoxy group (e.g., an epoxycyclohexyl group) and does not have a radical polymerizable group. Commercially available alicyclic epoxy compounds include Celoxide 8010 (trade name, bi-7-oxabicyclo[4.1.0]heptane, manufactured by Daicel Corporation), as well as, for example, EHPE3150, EHPE3150CE, Celoxide 2021P, and Celoxide 2081 (trade names, manufactured by Daicel Corporation). These may be used individually or in combination. As component (C1), epoxy compounds having aromatic hydrocarbon groups such as bisphenol A type epoxy resin and bisphenol F type epoxy resin (for example, trade names "jER1010" and "YL983U" manufactured by Mitsubishi Chemical Corporation) can also be used. Epoxy compounds having aromatic hydrocarbon groups may be used in combination with alicyclic epoxy compounds, as this further improves the reduction of connection resistance and provides superior connection reliability.

[0086] (C2) Component: Thermal cationic polymerization initiator Component (C2) is a thermal polymerization initiator (thermally latent cation generator) that generates an acid or the like upon heating to initiate polymerization. Component (C2) may be a salt compound composed of a cation and anion. For example, component (C2) is BF4 - , BR4 - (R represents a phenyl group substituted with two or more fluorine atoms or two or more trifluoromethyl groups.) PF6 - SbF6 - AsF6 - Examples include onium salts such as sulfonium salts, phosphonium salts, ammonium salts, diazonium salts, iodonium salts, anilinium salts, and pyridinium salts, which have anions such as those mentioned above. These may be used individually or in combination.

[0087] Component (C2) may be, for example, a salt compound having an anion containing boron as a constituent element, from the viewpoint of rapid curing. An example of such a salt compound is BF4. -Or BR4 - Examples of salt compounds having (R represents a phenyl group substituted with two or more fluorine atoms or two or more trifluoromethyl groups) are given. An anion containing boron as a constituent element is BR4. - It may be, and more specifically, tetrakis(pentafluorophenyl)borate.

[0088] Component (C2) may be a salt compound having a cation represented by the following formula (II) or formula (III) from the viewpoint of storage stability. [ka] [ka]

[0089] In formula (II), R 5 and R 6 Each of these independently represents an organic group containing a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aromatic hydrocarbon group having a substituent or being unsubstituted, and R 7 This represents an alkyl group having 1 to 6 carbon atoms.

[0090] The salt compound having a cation represented by formula (II) may be an aromatic sulfonium salt compound (aromatic sulfonium salt type thermal acid generator) from the viewpoint of achieving both storage stability and low-temperature activity. That is, R in formula (II) 5 and R 6 At least one of the groups may be an organic group containing a substituted or unsubstituted aromatic hydrocarbon group. The anion in the salt compound having the cation represented by formula (II) may be an anion containing antimony as a constituent element, for example, hexafluoroantimonate (hexafluoroantimonic acid).

[0091] Specific examples of compounds having a cation represented by formula (II) include 1-naphthylmethyl-p-hydroxyphenylsulfonium hexafluoroantimonate (manufactured by Sanshin Chemical Co., Ltd., SI-60 main component).

[0092] In formula (III), R 8 and R 9 Each of these independently represents an organic group containing a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aromatic hydrocarbon group having a substituent or being unsubstituted, and R 10 and R 11 Each of these independently represents an alkyl group having 1 to 6 carbon atoms.

[0093] Salt compounds having a cation represented by formula (III) (quaternary ammonium salt type thermal acid generators) have resistance to substances that can inhibit curing against cationic curing, and therefore may be, for example, an anilinium salt compound. That is, R in formula (III) 8 and R 9 At least one of the groups may be an organic group containing a substituted or unsubstituted aromatic hydrocarbon group. Examples of anilinium salt compounds include N,N-dialkylanilinium salts such as N,N-dimethylanilinium salt and N,N-diethylanilinium salt. The anion in the salt compound having the cation represented by formula (III) may be an anion containing boron as a constituent element, for example, tetrakis(pentafluorophenyl)borate.

[0094] The compound having the cation represented by formula (III) may be an anilinium salt having an anion containing boron as a constituent element. Examples of commercially available salt compounds of this type include CXC-1821 (trade name, manufactured by King Industries).

[0095] The content of component (C2) may be, for example, 0.1 to 20 parts by mass, 1 to 18 parts by mass, 3 to 15 parts by mass, or 5 to 12 parts by mass per 100 parts by mass of component (C1), from the viewpoint of ensuring the formability and curability of the adhesive film for forming the first adhesive layer.

[0096] From the viewpoint of ensuring the curability of the adhesive film for forming the first adhesive layer, the content of component (C) may be, for example, 5 parts by mass or more, 10 parts by mass or more, 15 parts by mass or more, or 20 parts by mass or more, per 100 parts by mass of the total amount of components other than component (A) in the first adhesive layer. From the viewpoint of ensuring the formability of the adhesive film for forming the first adhesive layer, the content of component (C) may be, for example, 70 parts by mass or less, 60 parts by mass or less, 50 parts by mass or less, or 40 parts by mass or less, per 100 parts by mass of the total amount of components other than component (A) in the first adhesive layer. From these viewpoints, the content of component (C) may be, for example, 5 to 70 parts by mass, 10 to 60 parts by mass, 15 to 50 parts by mass, or 20 to 40 parts by mass, per 100 parts by mass of the total amount of components other than component (A) in the first adhesive layer. The content of component (C) 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.

[0097] [Other ingredients] The first adhesive layer 1 may further contain other components in addition to component (A), the cured product of component (B), and component (C). Examples of other components include thermoplastic resin (hereinafter sometimes referred to as "component (D)"), coupling agent (hereinafter sometimes referred to as "component (E)"), and filler (hereinafter sometimes referred to as "component (F)").

[0098] Examples of component (D) include phenoxy resin, polyester resin, polyamide resin, polyurethane resin, polyester urethane resin, acrylic rubber, epoxy resin (solid at 25°C), etc. These may be used individually or in combination. By further containing component (D) in a composition containing components (B) and (C), a composition layer (and further, the first adhesive layer 1) can be easily formed from the composition. Examples of the phenoxy resin include fluorene-type phenoxy resin and bisphenol A-bisphenol F copolymer-type phenoxy resin.

[0099] The weight-average molecular weight (Mw) of component (D) may be, for example, 5000-200000, 10000-100000, 20000-80000, or 40000-60000, from the viewpoint of resin excludability during mounting. Note that Mw refers to the value measured by gel permeation chromatography (GPC) and converted using a calibration curve with standard polystyrene.

[0100] The content of component (D) may be, for example, 1 part by mass or more, 5 parts by mass or more, 10 parts by mass or more, or 20 parts by mass or more, 70 parts by mass or less, 60 parts by mass or less, 50 parts by mass or less, or 40 parts by mass or less, 1 to 70 parts by mass, 5 to 60 parts by mass, 10 to 50 parts by mass or 20 to 40 parts by mass, based on 100 parts by mass of the total amount of components other than component (A) in the first adhesive layer. The content of component (D) in the composition or composition layer for forming the first adhesive layer (based on the total mass of the composition or composition layer) may be the same as the above range.

[0101] Examples of component (E) include silane coupling agents having organic functional groups such as (meth)acryloyl groups, mercapto groups, amino groups, imidazole groups, and epoxy groups (e.g., γ-glycidoxypropyltrimethoxysilane), silane compounds such as tetraalkoxysilanes, tetraalkoxytitanate derivatives, and polydialkyltitanate derivatives. These may be used individually or in combination. The adhesion of the first adhesive layer 1 can be further improved by containing component (E). Component (E) may be, for example, a silane coupling agent.

[0102] The content of component (E) may be, for example, 0.1 to 10 parts by mass per 100 parts by mass of the total amount of components other than component (A) in the first adhesive layer. The content of component (E) in the composition or composition layer for forming the first adhesive layer (based on the total mass of the composition or composition layer) may be the same as the range described above.

[0103] Component (F) may be, for example, a non-conductive filler (e.g., non-conductive particles). Component (F) may be either an inorganic filler or an organic filler. Examples of inorganic fillers include metal oxide nanoparticles such as silica nanoparticles, alumina nanoparticles, silica-alumina nanoparticles, titania nanoparticles, and zirconia nanoparticles; and inorganic nanoparticles such as metal nitride nanoparticles. Examples of organic fillers include organic nanoparticles such as silicone nanoparticles, methacrylate-butadiene-styrene nanoparticles, acrylic-silicone nanoparticles, polyamide nanoparticles, and polyimide nanoparticles. These may be used individually or in combination. Component (F) may be, for example, silica nanoparticles. The content of component (F) may be, for example, 0.1 to 10 parts by mass per 100 parts by mass of the total amount of components other than component (A) in the first adhesive layer. The content of component (F) in the composition or composition layer for forming the first adhesive layer (based on the total mass of the composition or composition layer) may be the same as the range described above.

[0104] The first adhesive layer 1 may further contain other additives such as softeners, accelerators, degradation inhibitors, colorants, flame retardants, and thixotropic agents as other components. The amount of other additives may be, for example, 0.1 to 10 parts by mass per 100 parts by mass of the total amount of components other than component (A) in the first adhesive layer. The amount of other additives in the composition or composition layer for forming the first adhesive layer (based on the total mass of the composition or composition layer) may be the same as the range described above.

[0105] The thickness d1 of the first adhesive layer 1 may be, for example, 0.5 μm or more, 1.0 μm or more, or 2.0 μm or more, from the viewpoint of the transferability of conductive particles 4 during the manufacture of the adhesive film for circuit connection. The thickness d1 of the first adhesive layer 1 may be, for example, 5.0 μm or less, 4.0 μm or less, or 3.0 μm or less, from the viewpoint of being able to capture conductive particles more efficiently during connection. From these viewpoints, the thickness d1 of the first adhesive layer 1 may be, for example, 0.5 to 5.0 μm, 1.0 to 4.0 μm, or 2.0 to 3.0 μm. As shown in Figure 1, if a portion of the conductive particles 4 is exposed from the surface of the first adhesive layer 1 (for example, protruding toward the second adhesive layer 2), the distance from the surface 1a of the first adhesive layer 1 opposite to the second adhesive layer 2 to the boundary S between the first adhesive layer 1 and the second adhesive layer 2 located at the spaced portion between adjacent conductive particles 4,4 (the distance shown as d1 in Figure 1) is the thickness of the first adhesive layer 1, and the exposed portion of the conductive particles 4 is not included in the thickness of the first adhesive layer 1.

[0106] The thickness d1 of the first adhesive layer 1 can be determined, for example, by sandwiching an adhesive film between two pieces of glass (thickness: approximately 1 mm), casting a resin composition consisting of 100 g of bisphenol A type epoxy resin (product name: jER811, manufactured by Mitsubishi Chemical Corporation) and 10 g of a hardener (product name: Epomount hardener, manufactured by Refinetech Co., Ltd.), performing cross-sectional polishing using a polishing machine, and measuring the thickness using a scanning electron microscope (SEM, product name: SE-8020, manufactured by Hitachi High-Tech Science Corporation).

[0107] <Second adhesive layer> The second adhesive layer 2 is an insulating adhesive layer composed of, for example, a non-conductive component (insulating resin component). The second adhesive layer 2 contains at least component (C).

[0108] The details (types, combinations, etc.) of the components (e.g., components (C1), (C2), etc.) contained in component (C) (i.e., the second thermosetting component) in the second adhesive layer 2 are the same as the details of the components contained in component (C) (i.e., the first thermosetting component) in the first adhesive layer 1, so a detailed explanation is omitted here. The second thermosetting component may be the same as or different from the first thermosetting component.

[0109] From the viewpoint of maintaining reliability, the content of component (C) may be, for example, 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 preventing resin leakage defects in reels, which is one form of supply, the content of component (C) may be, for example, 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 these viewpoints, the content of component (C) may be, for example, 5 to 70% by mass, 10 to 15% by mass, 15 to 50% by mass, or 20 to 40% by mass, based on the total mass of the second adhesive layer.

[0110] The second adhesive layer 2 may further contain other components of the first adhesive layer 1 (components (D), (E), (F), and other additives, etc.). Preferred embodiments of the other components are the same as those of the preferred embodiments of the first adhesive layer 1.

[0111] The content of component (D) may be, for example, 1% by mass or more, 5% by mass or more, or 10% by mass or more, 80% by mass or less, 60% by mass or less, or 40% by mass or less, based on the total mass of the second adhesive layer, and may be 1 to 80% by mass, 5 to 60% by mass or 10 to 40% by mass.

[0112] The content of component (E) may be, for example, 0.1 to 10% by mass, based on the total mass of the second adhesive layer.

[0113] The content of component (F) may be, for example, 1% by mass or more, 10% by mass or more, or 30% by mass or more, 90% by mass or less, 70% by mass or less, or 50% by mass or less, or 1 to 90% by mass or less, 10 to 70% by mass or less, or 30 to 50% by mass, based on the total mass of the second adhesive layer.

[0114] The content of other additives may be, for example, 0.1 to 10% by mass, based on the total mass of the second adhesive layer.

[0115] The thickness d2 of the second adhesive layer 2 may be set appropriately according to the height of the electrodes of the circuit members to be connected. From the viewpoint of sufficiently filling the space between electrodes and sealing the electrodes, and obtaining better connection reliability, the thickness d2 of the second adhesive layer 2 may be, for example, 2 μm or more, 5 μm or more, or 10 μm or more, or 30 μm or less, 20 μm or less, or 15 μm or less, or 2 to 30 μm, 5 to 20 μm, or 10 to 15 μm. Note that, as shown in Figure 1, if a part of the conductive particles 4 is exposed from the surface of the first adhesive layer 1 (for example, protruding toward the second adhesive layer 2 side), the distance from the surface 2a of the second adhesive layer 2 opposite to the first adhesive layer 1 side to the boundary S between the first adhesive layer 1 and the second adhesive layer 2 located in the spaced portion between adjacent conductive particles 4, 4 (the distance shown as d2 in Figure 1) is the thickness of the second adhesive layer 2. The thickness d2 of the second adhesive layer 2 can be determined, for example, in the same manner as the method for measuring the thickness d1 of the first adhesive layer 1 described above.

[0116] The thickness of the circuit connection adhesive film 10A (the sum of the thicknesses of all layers constituting the circuit connection adhesive film 10A) may be, for example, 2.5 μm or more, 6 μm or more, or 12 μm or more, 35 μm or less, 24 μm or less, or 18 μm or less, or 2.5 to 35 μm, 6 to 24 μm, or 12 to 24 μm.

[0117] The circuit connection adhesive film 10A is an adhesive film used for connecting circuits. The circuit connection adhesive film 10A may or may not have anisotropic conductivity. That is, the circuit connection adhesive film may be an anisotropic conductive adhesive film or a non-anisotropic conductive (e.g., isotropic conductive) adhesive film. The circuit connection adhesive film 10A may be placed between the surface on which the first electrode of a first circuit member having a first electrode is provided and the surface on which the second electrode of a second circuit member having a second electrode is provided, and may be used to electrically connect the first electrode and the second electrode to each other via conductive particles (or molten solidified conductive particles) and to bond the first circuit member and the second circuit member by heating a laminate including the first circuit member, the circuit connection adhesive film 10A, and the second circuit member while pressing the laminate in the thickness direction of the laminate. The above-mentioned "anisotropic conductivity" means that it conducts in the direction of pressure and maintains insulating properties in the direction of non-pressure.

[0118] The circuit connection adhesive film 10A ensures the removal of resin during connection using a thermosetting component, while the cured product of the photocurable component suppresses the fluidity of conductive particles during connection, thereby improving the capture rate of conductive particles between connected electrodes. Therefore, the circuit connection adhesive film 10A provides a connection structure that is less prone to short circuits and has excellent conductivity between electrodes.

[0119] Although one embodiment of an adhesive film for circuit connection has been described above, the present invention is not limited to the above embodiment.

[0120] The circuit connection adhesive film may, for example, include a third adhesive layer 5 containing component (C) (thermosetting component) on the side of the first adhesive layer 1 opposite to the second adhesive layer 2, as shown in Figure 4, of the circuit connection adhesive film 10B. The third adhesive layer 5 is, for example, an insulating adhesive layer composed of a non-conductive component (insulating resin component). The circuit connection adhesive film 10B has the same configuration as the circuit connection adhesive film 10A, except that the third adhesive layer 5 is laminated.

[0121] The details of component (C) contained in the third adhesive layer 5 (hereinafter also referred to as the "third thermosetting component") are the same as those of the thermosetting component described above. For example, the third thermosetting component may contain component (C1) (i.e., a cationic polymerizable compound) and component (C2) (i.e., a thermal cationic polymerization initiator). Since the components (C1) and (C2) used in the third thermosetting component are the same as those used in the first thermosetting component, a detailed explanation is omitted here. The third thermosetting component may be the same as or different from the first thermosetting component. The third thermosetting component may be the same as or different from the second thermosetting component.

[0122] The content of component (C) may be, for example, 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 third adhesive layer, from the viewpoint of providing good transferability and peel resistance. The content of component (C) may be, for example, 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 third adhesive layer, from the viewpoint of providing good half-cutability and blocking resistance (suppression of resin seepage from the reel). From these viewpoints, the content of component (C) may be, for example, 5 to 70% by mass, 10 to 60% by mass, 15 to 50% by mass or 20 to 40% by mass, based on the total mass of the third adhesive layer.

[0123] The third adhesive layer 5 may further contain other components of the first adhesive layer 1. Preferred embodiments of the other components are the same as those of the preferred embodiments of the first adhesive layer 1.

[0124] The content of component (D) may be, for example, 10% by mass or more, 20% by mass or more, or 30% by mass or more, 80% by mass or less, 70% by mass or less, or 60% by mass or less, or 10 to 80% by mass, 20 to 70% by mass, or 30 to 60% by mass, based on the total mass of the third adhesive layer.

[0125] The content of component (E) may be, for example, 0.1 to 10% by mass, based on the total mass of the third adhesive layer.

[0126] The content of component (F) may be, for example, 1% by mass or more, 3% by mass or more, or 5% by mass or more, 50% by mass or less, 40% by mass or less, or 30% by mass or less, based on the total mass of the third adhesive layer, and may be 1 to 50% by mass, 3 to 40% by mass or 5 to 30% by mass.

[0127] The content of other additives may be, for example, 0.1 to 10% by mass, based on the total mass of the third adhesive layer.

[0128] The thickness d3 of the third adhesive layer 5 may be set appropriately according to the height of the electrodes of the circuit members to be bonded. From the viewpoint of sufficiently filling the space between electrodes and sealing the electrodes, and obtaining better connection reliability, the thickness d3 of the third adhesive layer 5 may be, for example, 0.1 μm or more, 0.5 μm or more, or 1.0 μm or more, or 10 μm or less, 5.0 μm or less, or 2.5 μm or less, or 0.1 to 10 μm, 0.5 to 5.0 μm, or 1.0 to 2.5 μm. The thickness d3 of the third adhesive layer 5 is the distance from the surface 5a of the third adhesive layer 5 opposite to the first adhesive layer 1 to the surface 1a of the first adhesive layer 1 opposite to the second adhesive layer 2 (the distance shown as d3 in Figure 4), and can be determined, for example, in the same manner as the measurement method for the thickness d1 of the first adhesive layer 1 described above.

[0129] If the adhesive film for circuit connection has layers other than the first adhesive layer and the second adhesive layer (for example, a third adhesive layer), the thickness of the adhesive film for circuit connection (the sum of the thicknesses of all the layers constituting the adhesive film for circuit connection) may be the same as the range that the thickness of the adhesive film for circuit connection 10A can take as described above.

[0130] <Method for manufacturing adhesive film for circuit connections> A method for manufacturing an adhesive film for circuit connection includes: preparing a substrate having a plurality of recesses on its surface, in which conductive particles are arranged in at least a portion of the plurality of recesses (preparation step); transferring conductive particles to the composition layer by providing a composition layer containing a photocurable component and a first thermosetting component on the surface of the substrate (the surface in which the recesses are formed) (transfer step); forming a first adhesive layer containing a plurality of conductive particles, a cured product of the photocurable component and a first thermosetting component by irradiating the composition layer with light (light irradiation step); and providing a second adhesive layer containing a second thermosetting component on one side of the first adhesive layer (lamination step).

[0131] The manufacturing method for the circuit connection adhesive film 10A described above will be explained below, with reference to Figures 5 to 10.

[0132] Figure 5 is a schematic diagram showing a longitudinal section of a substrate used in the manufacturing method of the circuit connection adhesive film 10A. Figure 6 is a diagram showing a modified cross-sectional shape of the recess of the substrate in Figure 5. Figure 7 is a schematic cross-sectional view showing the state in which conductive particles 4 are arranged in the recess of the substrate in Figure 5. Figure 8 is a schematic cross-sectional view showing an example of the preparation process. Figure 9 is a schematic cross-sectional view showing an example of the transfer process. Figure 10 is a schematic cross-sectional view showing an example of the light irradiation process.

[0133] (preparation process) In the preparation step, first, a substrate 6 having a plurality of recesses 7 on its surface is prepared (see Figure 5). The substrate 6 has a plurality of recesses 7. The plurality of recesses 7 are arranged regularly in a predetermined pattern (for example, a pattern corresponding to the electrode pattern of a circuit member). When the recesses 7 are arranged in a predetermined pattern, the conductive particles 4 are transferred to the composition layer in a predetermined pattern. As a result, a circuit connection adhesive film 10A is obtained in which the conductive particles 4 are arranged regularly in a predetermined pattern (a pattern as shown in Figures 2 and 3).

[0134] The recess 7 of the substrate 6 may be formed in a tapered shape, for example, as shown in Figure 5, where the opening area expands from the bottom 7a side of the recess 7 toward the surface 6a side of the substrate 6. That is, the width of the bottom 7a of the recess 7 (width a in Figure 5) may be narrower than the width of the opening of the recess 7 (width b in Figure 5). The size of the recess 7 (width a, width b, volume, taper angle, and depth, etc.) can be set according to the size of the target conductive particles and the position of the conductive particles in the adhesive film for circuit connection. For example, the width of the opening of the recess 7 (width b) may be larger than the maximum particle diameter of the conductive particles 4, and may be less than twice the maximum particle diameter of the conductive particles.

[0135] The shape of the recess 7 in the longitudinal section of the substrate 6 (the cross-sectional shape of the recess 7) may be, for example, the shape shown in Figures 6(a) to (h). In all of the cross-sectional shapes shown in Figures 6(a) to (h), the width of the opening of the recess 7 (width b) is the maximum width in the cross-sectional shape. This makes it easier to remove the conductive particles placed in the recess 7, improving work efficiency.

[0136] The shape of the opening of the recess 7 may be circular, elliptical, triangular, quadrilateral, polygonal, or the like.

[0137] The recess 7 of the substrate 6 can be formed by known methods such as lithography and machining. These methods allow for flexible design of the size and shape of the recess.

[0138] As materials constituting the substrate 6, for example, inorganic materials such as silicon, various ceramics, glass, and metals such as stainless steel, as well as organic materials such as various resins, can be used. As will be described later, in the manufacturing method of this embodiment, conductive particles 4 can be arranged in the recesses 7 of the substrate 6 by forming the conductive particles 4 in the recesses 7 of the substrate 6. In this case, the substrate 6 may have heat resistance so as not to be altered by the melting temperature of the fine particles (e.g., solder fine particles) used to form the conductive particles 4.

[0139] Next, conductive particles 4 (component (A) above) are placed (contained) in at least some (or all) of the multiple recesses 7 of the substrate 6 (see Figure 7).

[0140] The method of arranging the conductive particles 4 is not particularly limited. The arrangement method may be dry or wet. For example, the conductive particles 4 can be placed on the surface 6a of the substrate 6, and then the surface 6a of the substrate 6 can be rubbed with a squeegee or a micro-sticky roller to remove excess conductive particles 4 while arranging them in the recesses 7. If the width b of the opening of the recess 7 is greater than the depth of the recess 7, conductive particles may fly out of the opening of the recess 7. Using a squeegee removes conductive particles that have flown out of the opening of the recess 7. Other methods for removing excess conductive particles include blowing compressed air or rubbing the surface 6a of the substrate 6 with a nonwoven fabric or a bundle of fibers. These methods are preferable to using a squeegee because they exert less physical force, making them suitable for handling easily deformable conductive particles (e.g., solder particles).

[0141] When solder particles are used as conductive particles 4, the conductive particles 4 (solder particles) may be placed in the recesses 7 of the substrate 6 by forming the conductive particles 4 (solder particles) within the recesses 7. Specifically, for example, as shown in Figures 8(a) and 8(b), after housing fine particles 8 (solder fine particles) for forming the conductive particles 4 in the recesses 7, the conductive particles 4 can be formed in the recesses 7 by melting the fine particles 8 housed in the recesses 7. The fine particles 8 housed in the recesses 7 coalesce upon melting and become spherical due to surface tension. At this time, the molten metal takes on a shape that follows the bottom 7a at the contact point with the bottom 7a of the recesses 7. Therefore, for example, if the bottom 7a of the recesses 7 is flat as shown in Figure 8(a), the conductive particles 4 will have a flat portion 4a on a part of their surface as shown in Figure 8(b).

[0142] The fine particles 8 only need to be able to be contained within the recess 7, and it is acceptable for there to be large variations in particle size distribution or for the particles to be irregularly shaped.

[0143] One method for melting the fine particles 8 contained in the recess 7 is to heat the fine particles 8 to a temperature above the melting point of the material forming the fine particles. However, due to the influence of the oxide film, the fine particles 8 may not melt, wet and spread, or coalesce even when heated to a temperature above their melting point. For this reason, the fine particles 8 may be exposed to a reducing atmosphere to remove the surface oxide film of the fine particles 8, and then heated to a temperature above their melting point. This makes it easier to melt, wet and spread, and coalesce the fine particles 8. From a similar viewpoint, the melting of the fine particles 8 may be carried out under a reducing atmosphere.

[0144] The method for creating a reducing atmosphere is not particularly limited as long as it achieves the effects described above, and can include methods using hydrogen gas, hydrogen radicals, formic acid gas, etc. For example, by using a hydrogen reduction furnace, a hydrogen radical reduction furnace, a formic acid reduction furnace, or a conveyor furnace or continuous furnace of these, the fine particles 8 can be melted under a reducing atmosphere. These devices may be equipped with a heating device, a chamber filled with an inert gas (nitrogen, argon, etc.), a mechanism for creating a vacuum inside the chamber, etc., which makes it easier to control the reducing gas. Furthermore, if the chamber can be vacuumed, voids can be removed by reduced pressure after the melting and unification of the fine particles 8, and conductive particles 4 with even better connection stability can be obtained.

[0145] The profile of the reduction and dissolution conditions, temperature, and furnace atmosphere adjustment for the fine particles 8 may be set appropriately, taking into consideration the melting point, particle size, size of the recesses, and material of the substrate 6.

[0146] According to the above method, conductive particles 4 of substantially uniform size can be formed regardless of the material and shape of the fine particles 8. Furthermore, since the size and shape of the conductive particles 4 depend on the amount of fine particles 8 contained in the recess 7, the shape of the recess 7, etc., the size and shape of the conductive particles 4 can be freely designed by designing the recess 7 (adjusting the size, shape, etc. of the recess), and conductive particles having the desired particle size distribution (for example, conductive particles with an average particle diameter of 1 to 30 μm and a particle diameter CV value of 20% or less) can be easily prepared.

[0147] The above method is particularly suitable when the conductive particles 4 are indium-based solder particles. Indium-based solder can be deposited by plating, but it is difficult to deposit it in particulate form, and it is a soft and difficult-to-handle material. However, with the above method, by using indium-based solder fine particles as a raw material, indium-based solder particles with a substantially uniform particle size can be easily manufactured.

[0148] After the conductive particles 4 are placed in the recesses 7, the substrate 6 can be handled with the conductive particles 4 placed (settled) in the recesses 7. For example, when transporting or storing the substrate 6 with the conductive particles 4 placed (settled) in the recesses 7, deformation of the conductive particles 4 (especially soft conductive particles such as solder particles) can be prevented. In addition, since the conductive particles 4 can be easily removed when they are placed (settled) in the recesses 7, deformation of the conductive particles 4 during recovery, surface treatment, etc., can also be easily prevented.

[0149] (Transfer process) In the transfer process, conductive particles 4 are transferred to the composition layer 9 by providing a composition layer 9 containing a photocurable component (component (B) above) and a first thermosetting component (component (C) above) on the surface of the substrate 6 (the surface on which the recess 7 is formed) (see Figure 9).

[0150] Specifically, first, a composition layer 9 containing components (B) and (C) is formed on the support 11 to obtain a laminated film 12. Then, the surface of the substrate 6 where the recess 7 is formed (the surface of the substrate 6) 6a and the surface of the laminated film 12 facing the composition layer 9 (the surface of the composition layer 9 opposite to the support 11, 9a) are brought closer together (see Figure 9(a)). Next, the laminated film 12 and the substrate 6 are bonded together to bring the composition layer 9 into contact with the surface of the substrate 6 (the surface where the recess 7 is formed) 6a, thereby transferring the conductive particles 4 to the composition layer 9. This results in a particle transfer layer 13 comprising the composition layer 9 and conductive particles 4, at least a portion of which are embedded in the composition layer 9 (see Figure 9(b)). In this case, if the bottom of the recess 7 is flat, the conductive particles 4 will have a flat portion 4a corresponding to the shape of the bottom of the recess 7, and will be arranged in the composition layer 9 with this flat portion 4a facing away from the support 11.

[0151] The composition layer 9 can be formed using a varnish composition (a varnish-like first adhesive composition) prepared by dissolving or dispersing components (B) and (C), as well as other components added as needed, in an organic medium by stirring, mixing, kneading, etc. Specifically, for example, the composition layer 9 can be formed by applying the varnish composition onto a support 11 (e.g., a substrate that has undergone a release treatment) using a knife coater, roll coater, applicator, comma coater, die coater, etc., and then volatilizing the organic medium by heating. At this time, the thickness of the final obtained first adhesive layer (first adhesive film) can be adjusted by adjusting the amount of varnish composition applied.

[0152] The organic medium used in the preparation of the varnish composition is not particularly limited as long as it has the property of being able to dissolve or disperse each component substantially uniformly. Examples of such organic mediums include toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, and butyl acetate. These organic mediums can be used individually or in combination of two or more. Stirring, mixing, or kneading during the preparation of the varnish composition can be carried out using, for example, a stirrer, a 3-roll mill, a ball mill, a bead mill, a homodisper, etc.

[0153] The support 11 is not particularly limited as long as it has heat resistance that can withstand the heating conditions when the organic medium is volatilized. The support 11 may be a plastic film or a metal foil. As the support 11, for example, a substrate (e.g., 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, liquid crystal polymer, etc., may be used as the constituent material.

[0154] The heating conditions for volatilizing the organic medium from the varnish composition applied to the substrate can be appropriately set according to the organic medium used. For example, the heating conditions may be 40 to 120°C for 0.1 to 10 minutes.

[0155] Methods for bonding the laminated film 12 and the substrate 6 include, for example, heat pressing, roll lamination, and vacuum lamination. Lamination can be carried out, for example, under temperature conditions of 0 to 80°C.

[0156] In the transfer process, the composition layer 9 may be formed by directly applying the varnish composition to the substrate 6. However, by using the laminated film 12 as described above, it becomes easier to obtain a particle transfer layer 13 in which the support 11, the composition layer 9, and the conductive particles 4 are integrated, and the light irradiation process described later tends to be carried out more easily.

[0157] (Light irradiation process) In the light irradiation step, the composition layer 9 (particle transfer layer 13) is irradiated with light (active light) to cure component (B) in the composition layer 9 and form the first adhesive layer 1 (see Figure 10).

[0158] For light irradiation, irradiation light containing wavelengths in the range of 150 to 750 nm (e.g., ultraviolet light) may be used. Light irradiation can be carried out using, for example, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, metal halide lamps, LED light sources, etc. The integrated luminous intensity of the irradiated light can be set as appropriate, for example, 500 to 3000 mJ / cm². 2 That's fine.

[0159] As indicated by the arrow in Figure 10(a), in Figure 10(a), light is irradiated from the opposite side of the support 11 (the side on which the conductive particles 4 in the composition layer 9 are transferred). However, if the support 11 is transparent to light, light may be irradiated from the support 11 side. Also, in Figure 10(a), light irradiation is performed after separating the substrate 6 and the particle transfer layer 13, but light irradiation may be performed before separating the substrate 6. In this case, light irradiation may be performed after peeling off the support 11.

[0160] (Lamination process) In the lamination process, a second adhesive layer 2 is applied to the surface of the first adhesive layer 1 opposite to the support 11 (the side on which the conductive particles 4 in the composition layer 9 are transferred). This yields the circuit connection adhesive film 10A shown in Figure 1.

[0161] The second adhesive layer 2 can be provided on the first adhesive layer 1 in the same manner as the composition layer 9 is provided on the substrate 6, except that a varnish composition (a varnish-like second adhesive composition) is used, which is prepared by dissolving or dispersing a second thermosetting component (component (C) above) and other components added as needed in an organic medium by stirring, mixing, kneading, etc., instead of the varnish-like first adhesive composition. That is, the second adhesive layer 2 may be provided on the first adhesive layer 1 by bonding a laminated film obtained by forming the second adhesive layer 2 on a support to the first adhesive layer 1, or the second adhesive layer 2 may be provided on the first adhesive layer 1 by directly applying the varnish-like second adhesive composition to the first adhesive layer 1.

[0162] In the lamination process, by providing the second adhesive layer 2 on the surface opposite to the support 11, as described above, it is expected that the adhesion of the adhesive film for circuit connection to the circuit member will be improved and peeling during connection will be suppressed. In the lamination process, the second adhesive layer 2 may also be provided on the surface on which the support 11 was provided after the support 11 has been peeled off. In this case, the lamination process may be performed before the light irradiation process or before the transfer process.

[0163] The above describes one embodiment of a method for manufacturing a circuit connection adhesive film 10A, using the method for manufacturing the circuit connection adhesive film 10A as an example. However, the present invention is not limited to the above embodiment.

[0164] For example, a method for manufacturing a circuit connection adhesive film may further include providing a third adhesive layer on the surface of the first adhesive layer opposite to the second adhesive layer (second lamination step). This method yields a circuit connection adhesive film further comprising the third adhesive layer (for example, the circuit connection adhesive film 10B shown in Figure 4).

[0165] In the second lamination step, the third adhesive layer can be formed on the first adhesive layer in the same manner as the lamination step for forming the second adhesive layer (first lamination step), except that a composition containing a third thermosetting component (component (C) above) and other components added as needed (third adhesive composition) is provided instead of the second adhesive composition. The second lamination step may be performed before the first lamination step.

[0166] <Connecting structure and method for manufacturing the same> The following describes a connection structure (circuit connection structure) and its manufacturing method, using the above-mentioned circuit connection adhesive film 10A as the circuit connection material as an example.

[0167] Figure 11 is a schematic cross-sectional view showing one embodiment of the connection structure. As shown in Figure 11, the connection structure 100 includes a first circuit board 21 and a first circuit member 23 having a first electrode 22 formed on the main surface 21a of the first circuit board 21, a second circuit board 24 and a second circuit member 26 having a second electrode 25 formed on the main surface 24a of the second circuit board 24, and a connection portion 27 which includes a cured body of a circuit connection adhesive film 10A, electrically connects the first electrode 22 and the second electrode 25 to each other via conductive particles 4 (or molten solidified conductive particles 4), and adheres the first circuit member 23 and the second circuit member 26.

[0168] The first circuit member 23 and the second circuit member 26 may be the same or different from each other. The first circuit member 23 and the second circuit member 26 may be a glass or plastic substrate on which circuit electrodes are formed; a printed circuit board; a ceramic circuit board; a flexible circuit board; an IC chip such as a driving IC, etc. The first circuit board 21 and the second circuit board 24 may be formed from inorganic materials such as semiconductors, glass, and ceramics; organic materials such as polyimide and polycarbonate; or composite materials such as glass / epoxy. The first circuit board 21 may be a plastic substrate. The first circuit member 23 may be, for example, a plastic substrate on which circuit electrodes are formed (a plastic substrate whose constituent materials are organic materials such as polyimide, polycarbonate, polyethylene terephthalate, and cycloolefin polymer), and the second circuit member 26 may be, for example, an IC chip such as a driving IC. The plastic substrate on which the electrodes are formed may be a plastic substrate on which a display area is formed by regularly arranging, for example, a pixel driving circuit such as an organic TFT or a plurality of organic EL elements R, G, and B in a matrix.

[0169] The first electrode 22 and the second electrode 25 may be electrodes containing metals such as gold, silver, tin, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper, aluminum, molybdenum, and titanium, or oxides such as indium tin oxide (ITO), indium zinc oxide (IZO), and indium gallium zinc oxide (IGZO). The first electrode 22 and the second electrode 25 may also be electrodes formed by stacking two or more of these metals, oxides, etc. Electrodes formed by stacking two or more of these materials may have two or more layers, or three or more layers. The first electrode 22 and the second electrode 25 may be circuit electrodes or bump electrodes. In Figure 11, the first electrode 22 is a circuit electrode and the second electrode 25 is a bump electrode.

[0170] The connecting portion 27 includes, for example, a first region 28 located on the first circuit member 23 side in the direction in which the first circuit member 23 and the second circuit member 26 face each other (hereinafter referred to as the "opposing direction"), which includes cured material of component (B) and component (C), other than the conductive particles 4 in the first adhesive layer described above; a second region 29 located on the second circuit member 26 side in the opposing direction, which includes cured material of component (C), etc., in the second adhesive layer described above; and conductive particles 4 (or molten solidified conductive particles 4) interposed at least between the first electrode 22 and the second electrode 25 to electrically connect the first electrode 22 and the second electrode 25. The connecting portion 27 does not necessarily have two distinct regions between the first region 28 and the second region 29, and cured material derived from the first adhesive layer and cured material derived from the second adhesive layer may be mixed together to form a single region.

[0171] Examples of connection structures include a flexible organic electroluminescent color display (organic EL display) in which a plastic substrate with regularly arranged organic EL elements is connected to a drive circuit element that acts as a driver for displaying images, and a touch panel in which a plastic substrate with regularly arranged organic EL elements is connected to a position input element such as a touchpad. These connection structures can be applied to various monitors such as smartphones, tablets, televisions, vehicle navigation systems, and wearable devices; furniture; home appliances; and daily necessities.

[0172] Figure 12 is a schematic cross-sectional view showing one embodiment of a method for manufacturing the connection structure 100. Figures 12(a) and 12(b) are schematic cross-sectional views showing each step. As shown in Figure 12, the method for manufacturing the connection structure 100 includes placing the circuit connection adhesive film 10A between the surface of the first circuit member 23 on which the first electrode 22 is provided and the surface of the second circuit member 26 on which the second electrode 25 is provided, and heating the laminate including the first circuit member 23, the circuit connection adhesive film 10A, and the second circuit member 26 while pressing the laminate in the thickness direction of the laminate, thereby electrically connecting the first electrode 22 and the second electrode 25 to each other via conductive particles 4 (or molten solidified conductive particles 4) and bonding the first circuit member 23 and the second circuit member 26.

[0173] Specifically, first, a first circuit member 23 comprising a first circuit board 21 and a first electrode 22 formed on the main surface 21a of the first circuit board 21, and a second circuit member 26 comprising a second circuit board 24 and a second electrode 25 formed on the main surface 24a of the second circuit board 24 are prepared.

[0174] Next, the first circuit member 23 and the second circuit member 26 are arranged so that the first electrode 22 and the second electrode 25 face each other, and the circuit connection adhesive film 10A is placed between the first circuit member 23 and the second circuit member 26. For example, as shown in Figure 12(a), the circuit connection adhesive film 10A is laminated onto the first circuit member 23 so that the side with the first adhesive layer 1 faces the main surface 21a of the first circuit board 21. Next, the second circuit member 26 is placed on the first circuit member 23, to which the circuit connection adhesive film 10A has been laminated, so that the first electrode 22 on the first circuit board 21 and the second electrode 25 on the second circuit board 24 face each other.

[0175] Then, as shown in Figure 12(b), the laminate, which is formed by stacking the first circuit member 23, the circuit connection adhesive film 10A, and the second circuit member 26 in this order, is heated while being pressed in the thickness direction of the laminate, thereby thermocompressing the first circuit member 23 and the second circuit member 26 together. At this time, as indicated by the arrows in Figure 12(b), the flowable, uncured thermosetting components contained in the first adhesive layer 1 and the second adhesive layer 2 flow to fill the gaps between adjacent electrodes (the gaps between the first electrodes 22 and the gaps between the second electrodes 25), and harden due to the heating. As a result, the first electrode 22 and the second electrode 25 are electrically connected to each other via the conductive particles 4, and the first circuit member 23 and the second circuit member 26 are bonded to each other, resulting in the connection structure 100 shown in Figure 11.

[0176] In the manufacturing method of the above-described connection structure 100, a portion of the first adhesive layer 1 is cured by light irradiation, which suppresses the flow of conductive particles in the first adhesive layer 1, thus efficiently trapping the conductive particles between opposing electrodes. Furthermore, because the thermosetting components contained in the first adhesive layer 1 and the second adhesive layer 2 flow during heat-compression bonding, it becomes difficult for resin to interpose between the conductive particles 4 and the electrodes (first electrode and second electrode) after connection, thereby reducing the connection resistance between the opposing first electrode 22 and second electrode 25.

[0177] When solder particles are used as conductive particles, the solder particles melt and gather between the first electrode 22 and the second electrode 25 to form a solder layer. Subsequently, cooling causes the solder layer to solidify between the first electrode 22 and the second electrode 25, electrically connecting the first electrode 22 and the second electrode 25.

[0178] The heating temperature during connection can be set as appropriate, but for example, it may be between 50 and 190°C. When solder particles are used as conductive particles, the temperature should be such that the solder particles can melt (for example, a temperature higher than the melting point of the solder particles), for example, it may be between 130 and 260°C. The pressure is not particularly limited as long as it does not damage the adherend, but in the case of COP mounting, for example, the area-converted pressure at the bump electrode may be between 0.1 and 50 MPa, or 40 MPa or less, or between 0.1 and 40 MPa. In the case of COG mounting, for example, the area-converted pressure at the bump electrode may be between 10 and 100 MPa. The time for these heating and pressurizing steps may be in the range of 0.5 to 120 seconds. [Examples]

[0179] The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to the following examples.

[0180] In the examples and comparative examples, the following materials were used as components (B1), (B2), (C1), (C2), (C3), (C4), (D), (E), and (F). (B1) Component: Radical polymerizable compound • NK ester A-BPEF (9,9-bi[4-(2-acryloyloxyethoxy)phenyl]fluorene, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) • Lipoxy VR-90 (Bisphenol A type epoxy methacrylate, manufactured by Showa Denko Corporation) • Cyclomer M100 (3,4-epoxycyclohexylmethyl methacrylate, manufactured by Daicel Corporation) • A-1000 (Polyethylene glycol diacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.) • A9300-1CL (Caprolactone-modified tris-(2-acryloxyethyl) isocyanurate, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) (B2) Component: Photoradical polymerization initiator Irgacure OXE-02 (1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-ethanone 1-(O-acetyloxime), manufactured by BASF Japan Ltd.) • Omnirad907 (2-methyl-1-[4-(methylthio)phenyl]-2-morphonilopropan-1-one, manufactured by IGM RESINS BV) (C1) Component: Cationic polymerizable compound • ETERNACOLL OXBP (4,4'-bis[(3-ethyl-3-oxetanyl)methoxymethyl]biphenyl, manufactured by Ube Industries, Ltd.) • Celoxide 8010 (B-7-oxabicyclo[4.1.0]heptane, manufactured by Daicel Corporation) • jER1010 (Bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation) • YL983U (Bisphenol F type epoxy resin, manufactured by Mitsubishi Chemical Corporation) (C2) Component: Thermal cationic polymerization initiator (thermally latent cation generator) • CXC-1821 (Quaternary ammonium salt type thermoacid generator, manufactured by King Industries) • SI-60L (Aromatic sulfonium salt type thermal acid generator, manufactured by Sanshin Chemical Co., Ltd.) (C3) Component: Anionic polymerizable compound • HP-4032D (1,6-bis(oxyranylmethoxy)naphthalene, manufactured by DIC Corporation) (C4) Component: Thermal anionic polymerization initiator (thermally latent anion generator) • HX-3941HP (Microencapsulated imidazole-based curing accelerator, manufactured by Asahi Kasei Corporation) (D) Component: Thermoplastic resin • P-1: Fluorene-type phenoxy resin synthesized by the method described below. • YP-70 (Bisphenol A / Bisphenol F copolymer phenoxy resin, manufactured by Nippon Steel Chemical & Material Co., Ltd.) (E) Component: Coupling agent • KBM-403 (γ-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) (F) Component: Filler • Aerosil R805 (hydrolysis product of trimethoxyoctylsilane and silica (silica microparticles), manufactured by Evonik Industries AG, used diluted with organic solvent to 10% by mass of non-volatile content)

[0181] (Synthesis of P-1) 45 g of 4,4'-(9-fluorenylidene)-diphenol (manufactured by Sigma-Aldrich Japan Co., Ltd.) and 50 g of 3,3',5,5'-tetramethylbiphenol diglycidyl ether (YX-4000H, manufactured by Mitsubishi Chemical Corporation) were dissolved in 1000 mL of N-methylpyrrolidone in a 3000 mL three-necked flask equipped with a Liebig condenser, a calcium chloride tube, and a Teflon stirring rod ("Teflon" is a registered trademark) connected to a stirring motor, to prepare the reaction solution. 21 g of potassium carbonate was added to this, and the mixture was stirred while heating to 110 °C with a mantle heater. After stirring for 3 hours, the reaction solution was added dropwise to a beaker containing 1000 mL of methanol, and the resulting precipitate was filtered by suction filtration. The filtered precipitate was further washed three times with 300 mL of methanol to obtain 75 g of phenoxy resin P-1.

[0182] Subsequently, the molecular weight of phenoxy resin P-1 was measured using a high-performance liquid chromatograph GP8020 manufactured by Tosoh Corporation (column: Gerpak GL-A150S and GLA160S manufactured by Hitachi Chemical Co., Ltd., eluent: tetrahydrofuran, flow rate: 1.0 ml / min). As a result, the values ​​were Mn = 15769, Mw = 38045, and Mw / Mn = 2.413 in polystyrene equivalent.

[0183] <Example 1> (Process (a): Preparation process) [Step (a1): Preparation of the substrate] A substrate (PET film, thickness: 55 μm) with multiple recesses on its surface was prepared. The recesses were frustoconical in shape, with the opening area expanding toward the surface of the substrate (when viewed from the top of the opening, the center of the base and the center of the opening are the same), with an opening diameter of 4.3 μmφ, a base diameter of 4.0 μmφ, and a depth of 4.0 μm. The multiple recesses were formed regularly in a three-sided arrangement at intervals of 6.2 μm (distance between the centers of each base), resulting in 29,000 recesses per square millimeter.

[0184] [Process (a2): Arrangement of conductive particles] (A) As component, conductive particles (average particle diameter: 3.3 μm, CV value of particle diameter: 2.8%, specific gravity: 2.9) were prepared, consisting of a core (particle) made of plastic (cross-linked polystyrene) with a nickel layer of 0.15 μm thickness formed on its surface, and these were placed on the surface of the substrate where the recesses were formed. Next, excess conductive particles were removed by rubbing the surface of the substrate where the recesses were formed with a micro-adhesive roller, so that conductive particles were placed only within the recesses. The average particle diameter and CV value of the conductive particles were measured by observing 300 conductive particles with an SEM after cutting the first adhesive layer, which was prepared through steps (b) and (c) described later, into a 10 cm × 10 cm piece and applying Pt sputtering to the surface on which the conductive particles were placed.

[0185] (Step (b): Transfer step) [Process (b1): Preparation of the composition layer] Components (B1), (B2), (C1), (C2), (D), (E), and (F) shown in Table 1 were mixed with an organic solvent (2-butanone) in the amounts (units: parts by mass, solid content) shown in Table 1 to obtain a resin solution. Next, this resin solution was applied to a 38 μm thick PET film that had been silicone-released, and a 1.5 μm thick composition layer was prepared on the PET film by hot-air drying at 60°C for 3 minutes.

[0186] [Table 1]

[0187] [Process (b2): Transfer of conductive particles] The composition layer formed on the PET film prepared in step (b1) and the substrate in which conductive particles are arranged in the recesses, prepared in step (a), were placed facing each other, and the conductive particles were transferred to the composition layer.

[0188] (Step (c): Light irradiation step) For the composition layer onto which conductive particles have been transferred, a UV curing furnace (UVC-2534 / 1MNLC3-XJ01, manufactured by Ushio Inc.) is used to cure the conductive particles from the side with the transferred conductive particles using a metal halide lamp, with an integrated light intensity of 1700 mJ / cm². 2 Ultraviolet light with a wavelength of 365 nm was irradiated to activate component (B2) and polymerize component (B1). This cured the photocurable components (components (B1) and (B2)) in the composition layer, forming the first adhesive layer.

[0189] (Process (d): Lamination process) [Step (d1): Preparation of the second adhesive layer] Components (C1), (C2), (D), (E), and (F) shown in Table 2 were mixed with an organic solvent (2-butanone) in the amounts (units: parts by mass, solid content) shown in Table 2 to obtain a resin solution. Next, this resin solution was applied to a 50 μm thick PET film that had been silicone-released, and a second adhesive layer with a thickness of 12.5 μm was prepared on the PET film by hot-air drying at 60°C for 3 minutes.

[0190] [Table 2]

[0191] [Process (d2): Lamination of the second adhesive layer] The first adhesive layer prepared in step (c) and the second adhesive layer prepared in step (d1) were bonded together while applying a temperature of 50°C. This resulted in a two-layer anisotropic conductive adhesive film (thickness: 14 μm).

[0192] <Example 2> An anisotropic conductive adhesive film was prepared in the same manner as in Example 1, except that step (e) below was performed in addition to steps (a) to (d).

[0193] (Process (e): Second lamination process) [Step (e1): Preparation of the third adhesive layer] Components (C1), (C2), (D), (E), and (F) shown in Table 3 were mixed with an organic solvent (2-butanone) in the amounts (units: parts by mass, solid content) shown in Table 3 to obtain a resin solution. Next, this resin solution was applied to a 50 μm thick PET film that had been silicone-released, and a third adhesive layer with a thickness of 2.0 μm was prepared on the PET film by hot-air drying at 60°C for 3 minutes.

[0194] [Table 3]

[0195] [Process (e2): Lamination of the third adhesive layer] The first adhesive layer, exposed by peeling off the PET film on the first adhesive layer side of the anisotropic conductive adhesive film prepared in step (d2), was bonded to the third adhesive layer prepared in step (e1) while applying a temperature of 50°C. This resulted in obtaining a three-layer anisotropic conductive adhesive film (thickness: 16 μm).

[0196] <Examples 3-10, Comparative Example 1> A three-layer anisotropic conductive adhesive film was prepared in the same manner as in Example 2, except that the type and / or amount of the components to be blended in step (b1) was changed as shown in Table 4.

[0197] [Table 4]

[0198] <Example 11> In step (c), the integrated amount of light irradiated is 2000 mJ / cm². 2A three-layer anisotropic conductive adhesive film was prepared in the same manner as in Example 10, except for the change made to [specific component].

[0199] <Example 12> In process (c), the integrated amount of light irradiated is 2300 mJ / cm². 2 A three-layer anisotropic conductive adhesive film was prepared in the same manner as in Example 10, except for the change made to [specific component].

[0200] <Example 13> In step (b1), 1.0 part by mass of Omnirad907 was used as component (B2) instead of Irgacure OXE-02, and the integrated light intensity was 2000 mJ / cm². 2 A three-layer anisotropic conductive adhesive film was prepared in the same manner as in Example 2, except for the change made to [specific component].

[0201] <Example 14> A two-layer anisotropic conductive adhesive film was prepared in the same manner as in Example 1, except that in steps (b1) and (d1), 40 parts by mass of YL983U was used as component (C1) instead of ETERNACOLL OXBP and Celoxide 8010, and 7 parts by mass of SI-60L was used as component (C2) instead of CXC-1821.

[0202] <Example 15> A two-layer anisotropic conductive adhesive film was prepared in the same manner as in Example 1, except that in steps (b1) and (d1), 10 parts by mass of HP-4032D was used as component (C3) instead of component (C1), and 40 parts by mass of HX-3941HP was used as component (C4) instead of component (C2).

[0203] <Example 16> A two-layer anisotropic conductive adhesive film was prepared in the same manner as in Example 1, except that the following step (a2') was performed instead of step (a2), and the substrate obtained in the following step (a2') was used as the substrate in which conductive particles are arranged in the recesses for use in step (b2).

[0204] [Process (a2'): Preparation and placement of solder particles] 100g of Sn-Bi solder microparticles (manufactured by 5N Plus, melting point 138℃, Type 8) were immersed in distilled water, ultrasonically dispersed, and then leveled. The solder microparticles suspended in the supernatant were collected. This operation was repeated to collect 10g of solder microparticles. The average particle size of the obtained solder microparticles was 1.0 μm, and the CV value of the particle size was 42%. Next, the obtained solder microparticles (average particle size: 1.0 μm, CV value of particle size: 42%) were placed on the surface of the substrate prepared in step (a1) where the recesses were formed. Then, the surface of the substrate where the recesses were formed was rubbed with a micro-sticky roller to remove excess solder microparticles, so that the solder microparticles were placed only in the recesses. Next, the substrate with the solder microparticles placed in the recesses was placed in a hydrogen radical reduction furnace (manufactured by Shinko Seiki Co., Ltd., hydrogen plasma reflow apparatus), and after vacuuming, hydrogen gas was introduced into the furnace to fill it with hydrogen gas. Subsequently, the furnace temperature was adjusted to 120°C, and hydrogen radicals were irradiated for 5 minutes. After that, the hydrogen gas in the furnace was removed by vacuuming, and the temperature was heated to 145°C. Nitrogen was then introduced into the furnace to return it to atmospheric pressure, and the temperature inside the furnace was lowered to room temperature to form solder particles. This prepared a substrate with conductive particles (solder particles) arranged in the recesses, which would be used in process (b2).

[0205] Solder particles were separately produced by the same operation, and the obtained solder particles were recovered from the recess of the substrate by tapping the back side of the recess. It was confirmed that the solder particle has a flat portion on a part of its surface, and the ratio of the diameter B of the flat portion to the diameter A of the solder particle (B / A) is 0.15. Further, when a rectangle circumscribing the projected image of the solder particle was formed by two pairs of parallel lines, it was confirmed that when the distances between opposing sides are defined as X and Y (where Y<X), Y / X is 0.93. Further, when the average particle diameter of the solder particles and the C.V. value of the particle diameter were measured, the average particle diameter was 3.8 µm, and the C.V. value of the particle diameter was 7.9%. The average particle diameter, B / A, and Y / X of the solder particles are values measured by cutting the first adhesive layer produced through steps (b) and (c) into a 10 cm × 10 cm piece, performing Pt sputtering on the surface where the solder particles are arranged, and then observing 300 solder particles with SEM.

[0206] <Example 17> An anisotropic conductive adhesive film with a three-layer structure was produced in the same manner as in Example 2, except that the above step (a2') was performed instead of step (a2).

[0207] <Comparative Example 2> An anisotropic conductive adhesive film with a three-layer structure was produced in the same manner as in Example 2, except that step (c) was not performed.

[0208] <Evaluation> (Evaluation of Transfer Rate of Conductive Particles) For the anisotropic conductive adhesive films of Examples 1 to 17 and Comparative Examples 1 to 2, using a microscope and image analysis software (ImagePro, manufactured by Hakuto Co., Ltd.), 25,000 µm 2 the number of conductive particles per area was actually measured at 20 locations, and the average value was converted to 1 mm 2The number of conductive particles per unit area was converted and divided by the number of recesses formed in the substrate to measure the transfer rate of conductive particles (see formula below). A transfer rate of 95% or higher was judged as "S", a transfer rate of 90% or more but less than 95% was judged as "A", a transfer rate of 80% or more but less than 90% was judged as "B", and a transfer rate of less than 80% was judged as "C". The results are shown in Tables 5 to 7. Transfer rate of conductive particles (%) = (Average density of conductive particles in the anisotropic conductive adhesive film / Density of recesses formed in the substrate) × 100

[0209] (Evaluation of the trapping rate of conductive particles and evaluation of connection resistance) [Preparation of circuit components] As the first circuit component (a), a wiring pattern of AlNd (100 nm) / Mo (50 nm) / ITO (100 nm) (pattern width: 19 μm, inter-electrode space: 5 μm) was formed on the surface of an alkali-free glass substrate (OA-11, manufactured by Nippon Electric Glass Co., Ltd., outer dimensions: 38 mm x 28 mm, thickness: 0.3 mm). As the first circuit component (b), a wiring pattern of Cr (20 nm) / Au (200 nm) (pattern width: 19 μm, inter-electrode space: 5 μm) was formed on the surface of an alkali-free glass substrate (OA-11, manufactured by Nippon Electric Glass Co., Ltd., outer dimensions: 38 mm x 28 mm, thickness: 0.3 mm). As a second circuit component, an IC chip was prepared with bump electrodes arranged in a staggered pattern in two rows (outer dimensions: 0.9 mm × 20.3 mm, thickness: 0.3 mm, bump electrode size: 70 μm × 12 μm, space between bump electrodes: 12 μm, bump electrode thickness: 8 μm).

[0210] [Creation of the connecting structure (a)] Connecting structures (a) were fabricated using the anisotropic conductive adhesive films of Examples 1-13 and Comparative Examples 1-2, respectively. The anisotropic conductive adhesive film was placed on the first circuit member (a) so that the first adhesive layer or the third adhesive layer was in contact with the first circuit member (a). A thermocompression bonding apparatus (BS-17U, manufactured by Ohashi Seisakusho Co., Ltd.) consisting of a ceramic heater stage and a tool (8 mm x 50 mm) was used at 70°C and 0.98 MPa (10 kgf / cm²). 2 The anisotropic conductive adhesive film was attached to the first circuit member (a) by heating and pressurizing for 2 seconds under the specified conditions, and the release film on the side of the anisotropic conductive adhesive film opposite to the first circuit member (a) was peeled off. Next, the bump electrodes of the first circuit member (a) and the circuit electrodes of the second circuit member were aligned, and then the second adhesive layer of the anisotropic conductive adhesive film was attached to the second circuit member by heating and pressurizing at 40 MPa for 5 seconds at 130°C to fabricate the connecting structure (a). Note that the temperature is the measured maximum temperature reached by the anisotropic conductive adhesive film, and the pressure is the value calculated relative to the total area of ​​the surfaces on which the bump electrodes of the second circuit member face the first circuit member (a).

[0211] [Creation of the connecting structure (b)] The connecting structure (b) was fabricated in the same manner as the connecting structure (a), except that the anisotropic conductive adhesive film of Example 14 was used as the anisotropic conductive adhesive film, and the heating and pressurizing process was performed at 140°C for 5 seconds at 60 MPa.

[0212] [Creation of the connection structure (c)] The connecting structure (c) was fabricated in the same manner as the connecting structure (a), except that the anisotropic conductive adhesive film of Example 15 was used as the anisotropic conductive adhesive film, and the heating and pressurizing process was performed at 230°C for 5 seconds at 60 MPa.

[0213] [Creation of the connecting structure (d)] The connecting structure (d) was fabricated in the same manner as the connecting structure (a), except that the anisotropic conductive adhesive films of Examples 16 and 17 were used as the anisotropic conductive adhesive films, the first circuit member (b) was used instead of the first circuit member (a), and the structure was heated and pressurized at 30 MPa for 5 seconds at 160°C.

[0214] [Evaluation of the trapping rate of conductive particles] In the fabrication of the above-mentioned connection structures (connection structures (a) to (d)) using the anisotropic conductive adhesive films of Examples 1 to 17 and Comparative Examples 1 to 2, the capture rate of conductive particles between the bump electrodes and the circuit electrodes was evaluated. Here, the capture rate of conductive particles refers to the ratio of the density of conductive particles on the bump electrodes to the density of conductive particles in the anisotropic conductive adhesive film, and was calculated using the following formula. The average number of conductive particles on the bump electrodes was determined by observing the mounted circuit component from the glass substrate side using a differential interference microscope and measuring the number of conductive particles captured per bump. A capture rate of 90% or more was judged as "S", a capture rate of 80% or more but less than 90% was judged as "A", a capture rate of 70% or more but less than 80% was judged as "B", and a capture rate of less than 70% was judged as "C". The results are shown in Tables 5 to 7. Conductive particle capture rate (%) = (Average number of conductive particles on the bump electrode / (Bump electrode area × Density of conductive particles in anisotropic conductive adhesive film)) × 100

[0215] [Evaluation of connection resistance] Immediately after producing the connection structure and after the high-temperature and high-humidity test, the connection resistance at 14 locations was measured by the four-terminal measurement method, and the connection resistance of Examples 1 to 17 and Comparative Examples 1 to 2 was evaluated using the maximum measured connection resistance value. The high-temperature and high-humidity test was performed by treating the connection structure for 500 hours in a high-temperature and high-humidity chamber at a temperature of 85°C and a humidity of 85%RH. In addition, a multimeter (MLR21, manufactured by Kusumoto Chemicals, Ltd.) was used to measure the connection resistance. Evaluation was performed such that when the connection resistance value is less than 1.0Ω, it is rated "S"; when the connection resistance value is 1.0Ω or more and less than 2.5Ω, it is rated "A"; when the connection resistance value is 2.5Ω or more and less than 5.0Ω, it is rated "B"; when the connection resistance value is 5.0Ω or more and less than 10.0Ω, it is rated "C"; and when the connection resistance value is 10.0Ω or more, it is rated "D". The results are shown in Tables 5 to 7.

[0216] [Table 5]

[0217] [Table 6]

[0218] [Table 7] [Description of Reference Signs]

[0219] 1...first adhesive layer, 2...second adhesive layer, 3...adhesive component, 4...conductive particles, 5...third adhesive layer, 6...base body, 7...recess, 9...composition layer, 10A, 10B...adhesive film for circuit connection, 21...first circuit board, 22...first electrode (circuit electrode), 23...first circuit member, 24...second circuit board, 25...second electrode (bump electrode), 26...second circuit member, 27...connection part, 100...connection structure.

Claims

1. A substrate is prepared having a plurality of recesses on its surface, in which conductive particles are arranged in at least a portion of the plurality of recesses, The conductive particles are transferred to the composition layer by providing a composition layer containing a photocurable component having radical curability and a first thermosetting component that does not have radical curability on the surface of the substrate. By irradiating the composition layer with light, a first adhesive layer containing a plurality of conductive particles, a cured product of the photocurable component, and the first thermosetting component is formed. This includes providing a second adhesive layer containing a second thermosetting component on one surface of the first adhesive layer, The photocurable component comprises a radical polymerizable compound represented by the following formula (1) and a photoradical polymerization initiator, A method for producing an adhesive film for circuit connections, wherein the first thermosetting component comprises a cationic polymerizable compound and a thermal cationic polymerization initiator. 【Chemistry 1】 [In formula (1), R １ [wherein X represents a hydrogen atom or a methyl group, and X represents an alkanediyl group having 1 to 3 carbon atoms.]

2. A method for producing a circuit connection adhesive film according to claim 1, wherein the first thermosetting component includes a compound having a cyclic ether group as the cationic polymerizable compound.

3. The method for producing a circuit connection adhesive film according to claim 1, wherein the first thermosetting component includes at least one selected from the group consisting of oxetane compounds and alicyclic epoxy compounds as the cationic polymerizable compound.

4. A method for producing a circuit connection adhesive film according to any one of claims 1 to 3, wherein the photocurable component includes a compound represented by the following formula (I) as the photoradical polymerization initiator. 【Chemistry 2】 [In formula (I), R ２ , R ３ and R ４ Each of these independently represents an organic group containing a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aromatic hydrocarbon group.

5. A method for producing an adhesive film for circuit connections according to any one of claims 1 to 4, wherein the first thermosetting component includes a salt compound having a cation represented by the following formula (II) or the following formula (III) as the thermal cationic polymerization initiator. 【Transformation 3】 [In formula (II), R ５ and R ６ Each of these independently represents an organic group containing a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aromatic hydrocarbon group having a substituent or being unsubstituted, and R ７ This represents an alkyl group having 1 to 6 carbon atoms. 【Chemistry 4】 [In formula (III), R ８ and R ９ each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an organic group including a substituted or unsubstituted aromatic hydrocarbon group, and R １０ and R １１ each independently represent an alkyl group having 1 to 6 carbon atoms.]]

6. The average particle diameter of the conductive particles is 1 to 30 μm. A method for manufacturing an adhesive film for circuit connections according to any one of claims 1 to 5, wherein the C.V. value of the particle size of the conductive particles is 20% or less.

7. A method for manufacturing an adhesive film for circuit connection according to any one of claims 1 to 6, wherein when a quadrilateral circumscribing the projection image of the conductive particles is created by two pairs of parallel lines, and the distances between opposing sides are X and Y (where Y < X), X and Y satisfy the following formula. 0.8<Y / X≦1.0

8. A method for manufacturing an adhesive film for circuit connection according to any one of claims 1 to 7, wherein the plurality of recesses are formed in a predetermined pattern.

9. A circuit connection adhesive film containing conductive particles, The adhesive comprises a first adhesive layer containing a plurality of conductive particles, a cured product of a photocurable component having radical curability, and a first thermosetting component that does not have radical curability, and a second adhesive layer provided on the first adhesive layer and containing a second thermosetting component. The photocurable component comprises a radical polymerizable compound represented by the following formula (1) and a photoradical polymerization initiator, The first thermosetting component comprises a cationic polymerizable compound and a thermal cationic polymerization initiator. A circuit connection adhesive film in which at least a portion of the plurality of conductive particles are arranged in a predetermined pattern in a plan view of the circuit connection adhesive film, and in a longitudinal cross-section of the circuit connection adhesive film, adjacent conductive particles are arranged laterally while being separated from each other. 【Transformation 5】 [In formula (1), R １ [wherein X represents a hydrogen atom or a methyl group, and X represents an alkanediyl group having 1 to 3 carbon atoms.]

10. A first circuit member having a first electrode, A second circuit member having a second electrode, A connection structure comprising a cured body of the adhesive film for circuit connection described in claim 9, and a connection portion that electrically connects the first electrode and the second electrode to each other via the conductive particles and adheres the first circuit member and the second circuit member.

11. The circuit connection adhesive film according to claim 9 is placed between the surface on which the first electrode of the first circuit member having the first electrode is provided and the surface on which the second electrode of the second circuit member having the second electrode is provided. A method for manufacturing a connection structure, comprising: heating a laminate including the first circuit member, the circuit connection adhesive film, and the second circuit member while pressing the laminate in the thickness direction of the laminate, thereby electrically connecting the first electrode and the second electrode to each other via the conductive particles and bonding the first circuit member and the second circuit member.

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