Anisotropic conductive adhesive and connection structure

Abstract

An anisotropic conductive adhesive includes a resin having a main chain with a heterocyclic body, and a conductive material.

Description

Technical Field

[0001] This invention relates to anisotropic conductive adhesives and connecting structures. Background Technology

[0002] With the increasing performance, speed, and miniaturization of electronic devices, semiconductor circuits are being miniaturized to the nanometer level. In semiconductor packaging processes, for example, for a die formed with wiring capable of transistors and input / output relative to a semiconductor such as silicon, the substrate that performs the input / output is electrically connected and sealed. When connections are made using existing soldering techniques, the wiring spacing on the die side and the wiring spacing on the substrate side are limited to tens of micrometers due to the characteristics of solder bumps.

[0003] To eliminate the limitations of wiring spacing on the die side, FOWLP (Fan-Out Wafer-Level Packaging) has been developed. As a representative example, it is known that rewiring (RDL) is performed on the electrode surface of the die through wafer processing, thereby forming electrodes with wiring spacing capable of substrate connection on the die surface. As a result, the wiring inside the die can be miniaturized, enabling die miniaturization and high performance.

[0004] However, not limited to electrodes derived through FOWLP, in through-silicon via (TSV) electrodes, where the connection between the die and the substrate is made by solder, the tens of μm pitch, which is a characteristic limit of solder bumps, becomes an industrial limitation.

[0005] On the other hand, a great deal of research has been conducted on solder replacement technologies, with one example being a film-like bonding material (e.g., anisotropic conductive film (ACF)) that involves coating a thermosetting resin containing conductive material onto a release film.

[0006] This anisotropic conductive film, as a connection material that can be applied using low-temperature processes, is used for electrical connections in display peripheral devices, etc. For example, a multilayer substrate is reported in which a semiconductor substrate is stacked using anisotropic conductive film, which can provide a multilayer substrate with excellent conductivity characteristics at low cost with a simple manufacturing process. As such, the multilayer substrate is a multilayer substrate in which semiconductor substrates with through electrodes are stacked. When viewed from above, conductive particles are selectively present at the positions opposite the through electrodes. The opposite through electrodes are connected by conductive particles, and the semiconductor substrates with the through electrodes are bonded to each other by an insulating adhesive (for example, see Patent Document 1).

[0007] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2020-202409 Summary of the Invention The problem the invention aims to solve However, compared to the connection materials used in display peripherals, semiconductor device connection materials require high electrical connection reliability, including high-temperature-driven temperature cycling and reflow resistance. Existing anisotropic conductive films lack proven track records as connection materials in semiconductor devices such as FOWLP.

[0008] Furthermore, in existing solder joints, as mentioned above, there are limitations to narrowing the pitch. With miniaturization, it becomes difficult to fill the bottom to prevent short circuits. At the same time, the solder melting temperature is as high as 200°C or more. Therefore, there is a problem that when the temperature returns to room temperature, the substrate warps, which becomes a cause of defects in subsequent processes.

[0009] The objective of this invention is to solve the aforementioned problems and achieve the following: that is, to provide an anisotropic conductive adhesive that exhibits high electrical connection reliability and excellent adhesion even after temperature cycling.

[0010] Methods for solving problems As a method for solving the above-mentioned problems, the following is an example. That is, <1> An anisotropic conductive adhesive, characterized in that it comprises: a resin having a heterocyclic main chain and a conductive material.

[0011] <2> According to claim 1, the anisotropic conductive adhesive, wherein the resin having a heterocyclic structure in the main chain is represented by the following general formula (1) or the following general formula (2).

[0012] [Chemistry 1] In the above general formula (1), X represents a group selected from the group consisting of the following, Ar1 and Ar2 each represent an aryl group having one or more benzene rings, and n represents an integer.

[0013] [Chemistry 2] [Chemistry 3] In the above general formula (2), Y represents the group composed of the following, Ar1 and Ar2 each represent an aryl group having one or more benzene rings, and n represents an integer.

[0014] [Chemistry 4] <3> According to the above <1> The anisotropic conductive adhesive, wherein the resin having a heterocyclic main chain is represented by the following general formula (1) or the following general formula (2).

[0015] [Chemistry 5] In the above general formula (1), X, Ar1 and Ar2 each represent groups selected from the group consisting of the following, and n represents an integer.

[0016] [Chemistry 6] [Chemistry 7] In the above general formula (2), Y, Ar1 and Ar2 each represent groups selected from the group consisting of the following, and n represents an integer.

[0017] [Chemistry 8] <4> According to the above <1> ~ <3> In any one of the anisotropic conductive adhesives, the content of the resin having heterocyclic structures in the main chain is 20% by mass or more and 80% by mass or less relative to the resin composition.

[0018] <5> According to the above <1> ~ <4> The anisotropic conductive adhesive described in any one of the above statements, wherein the resistivity of the conductive material is 120 × 10⁻⁶. -8 [Ω [m] and below.

[0019] <6> According to the above <1> ~ <5> The anisotropic conductive adhesive described in any one of the above methods, wherein the conductive material comprises at least one selected from Au, Ag, Sn, Pb, Cu, Al, Ni and Fe.

[0020] <7> According to the above <1> ~ <6> The anisotropic conductive adhesive according to any one of the following methods, wherein the conductive material comprises at least one selected from metal particles, alloy particles and core-shell particles.

[0021] <8> According to the above <1> ~ <7> The anisotropic conductive adhesive according to any one of the following further comprises a curing agent.

[0022] <9> According to the above <1> ~ <8> The anisotropic conductive adhesive described in any one of the following further comprises other resins.

[0023] <10> According to the above <1> ~ <9> The anisotropic conductive adhesive described in any one of the following methods is an anisotropic conductive adhesive film.

[0024] <11> According to the above <1> ~ <10> The anisotropic conductive adhesive described in any one of the above-mentioned methods is an anisotropic conductive adhesive film in which the conductive material is arranged in a single layer in the film-like resin component.

[0025] <12> A connecting structure, characterized in that it has First circuit component, The second circuit component, and The above-mentioned first circuit component and the above-mentioned second circuit component are anisotropically conductively connected. <1> ~ <11> The anisotropic conductive adhesive as described in any one of the following.

[0026] The effects of the invention According to the present invention, the aforementioned problems can be solved and the above-mentioned objectives can be achieved, providing an anisotropic conductive adhesive that has high electrical connection reliability and excellent adhesion even after temperature cycling. Attached Figure Description

[0027]

Figure 1

[0028]

Figure 2

[0029]

Figure 3

[0030]

Figure 4

[0031] (Anisotropic conductive adhesive) The anisotropic conductive adhesive of the present invention comprises: a resin component including a resin having a heterocyclic main chain, and a conductive material, and further includes, as needed, other components such as a curing agent.

[0032] The above-mentioned anisotropic conductive adhesive is suitable for use as a paste-like anisotropic conductive adhesive or a film-like anisotropic conductive film for anisotropically conductively connecting the terminals of the first circuit component and the terminals of the second circuit component.

[0033] <Conductive Materials> As for the aforementioned conductive materials, there are no particular limitations if they are conductive, and they can be appropriately selected according to the purpose. For example, metal particles, alloy particles, core-shell particles, etc. can be used alone or in combination of two or more.

[0034] The resistivity of the above-mentioned conductive material is preferably 120 × 10⁻⁶. -8 [Ω [m] and below.

[0035] As the aforementioned conductive material, it is preferred to include at least one selected from Au, Ag, Sn, Pb, Cu, Al, Ni, and Fe.

[0036] The aforementioned metal particles are particles containing a single metal. There are no particular restrictions on the metals mentioned above, and they can be appropriately selected according to the purpose. For example, Au, Ag, Sn, Pb, Cu, Al, Ni, Fe, etc. can be cited.

[0037] The aforementioned alloy particles are particles of an alloy containing multiple metals, preferably containing two or more metals selected from Au, Ag, Sn, Pb, Cu, Al, Ni and Fe.

[0038] Among these, it is preferred to include at least one of Ni, Ag, and Cu. These conductive materials can be coated with Au or Pd (palladium) to prevent surface oxidation. Furthermore, products with an insulating film applied to the surface using an organic material can be used.

[0039] If the aforementioned core-shell particles are particles in which the metal particles, alloy particles, or resin particles serving as the core are coated with a shell of a different metal or alloy than the core, there are no particular restrictions, and appropriate selection can be made according to the purpose. For example, particles in which the surface of the metal particles, alloy particles, or resin particles is coated with at least one metal or alloy selected from Au, Ag, Sn, Pb, Cu, Al, Ni, and Fe can be cited.

[0040] The shell can cover the entire surface of the core, or it can cover a portion of the surface of the core. Furthermore, a material with an insulating film applied to the surface using metal protrusions or organic matter can be used. Considering low-resistance connections, particles whose surfaces are coated with Au or Ag are preferred.

[0041] There are no particular limitations on the method of coating the aforementioned resin particles with metal or alloy, and an appropriate method can be selected according to the purpose. For example, non-electrolytic plating and sputtering methods can be cited.

[0042] There are no particular restrictions on the materials used for the aforementioned resin particles, and appropriate selections can be made according to the purpose. Examples include styrene-divinylbenzene copolymer, benzoguanamine resin, cross-linked polystyrene resin, acrylic resin, and styrene-silica composite resin.

[0043] When the aforementioned conductive materials are anisotropically conductively connected, they only need to be conductive. For example, even if the particles have an insulating film applied to their surface, if the particles deform and the metal particles are exposed when they are anisotropically conductively connected, they become the aforementioned conductive material.

[0044] There are no particular limitations on the average particle size of the above-mentioned conductive material, and it can be appropriately selected according to the purpose. It is preferably 1μm to 50μm, more preferably 2μm to 25μm, and particularly preferably 2μm to 10μm.

[0045] The average particle size mentioned above is the average value of the particle size measured for any 10 conductive materials.

[0046] The aforementioned particle size can be measured, for example, by observation using a scanning electron microscope.

[0047] There are no particular limitations on the content of the conductive material mentioned above, and it can be appropriately selected according to the purpose. It is preferably 2 to 200 parts by mass relative to 100 parts by mass of the resin component, and more preferably 5 to 100 parts by mass.

[0048] <Resin Composition> The above-mentioned resin components include resins with heterocyclic main chains, and preferably further include other resins such as film-forming resins and thermosetting resins as needed.

[0049] The above-mentioned resin component is a resin containing heterocyclic structures in the main chain with excellent heat resistance. Therefore, due to the characteristics of resins that are strong in deformation and deterioration caused by heat, it can maintain a state with little deformation and deterioration even after temperature cycling. It can provide an anisotropic conductive adhesive with high electrical connection reliability that meets the specifications of semiconductor interconnection and excellent adhesion.

[0050] <<Resins with heterocyclic main chains>> The resin with a heterocyclic main chain is a resin with a heterocyclic main chain containing heteroatoms other than carbon and hydrogen. Examples of heteroatoms include nitrogen (N) and oxygen (O), and it is preferred to include N and O.

[0051] There are no particular limitations on the resins whose main chain has heterocyclic structures, and appropriate selection can be made according to the purpose. Examples include polyimide, polybenzoxazole, and polymaleimide.

[0052] They can be used individually or in combination with more than one type.

[0053] As the above-mentioned polyimide or polybenzoxazole, suitable examples include resins represented by the following general formula (1).

[0054] [Chemistry 9] In the above general formula (1), X represents a group selected from the group consisting of the following, Ar1 and Ar2 each represent an aryl group having one or more benzene rings, and n represents an integer.

[0055] [Chemistry 10] As for the aforementioned "aryl group having one or more benzene rings", there are no particular restrictions on having one or more benzene rings, and appropriate selection can be made according to the purpose. It may have substituents, and preferably has one, two or three benzene rings.

[0056] In the case of having two or more benzene rings, each benzene ring is preferably connected by covalent bonds, ether groups (-O-), carbonyl groups (-C(=O)-), etc.

[0057] Examples of substituents mentioned above include alkyl groups such as methyl (monovalent), and alkylene groups such as methylene and isopropylidene (=C(CH3)2) (divalent).

[0058] Of these, Ar1 and Ar2 preferably represent groups selected from the group consisting of the following.

[0059] [Chemistry 11] Among the resins shown in the above general formula (1), the resins shown in the following general formula (1-1), the resins shown in the following general formula (1-2), and mixtures thereof are preferred.

[0060] [Chemistry 12] As the above-mentioned polymaleimide, the resin shown in the following general formula (2) is appropriately exemplified.

[0061] [Chemistry 13] In the above general formula (2), Y represents the group composed of the following, Ar1 and Ar2 each represent an aryl group having one or more benzene rings, and n represents an integer.

[0062] [Chemistry 14] As for the aforementioned "aryl group having one or more benzene rings", there are no particular restrictions on having one or more benzene rings, and appropriate selection can be made according to the purpose. It may have substituents, and preferably has one, two or three benzene rings.

[0063] In the case of having two or more benzene rings, each benzene ring is preferably connected by covalent bonds, ether groups (-O-), carbonyl groups (-C(=O)-), etc.

[0064] Examples of substituents mentioned above include alkyl groups such as methyl (monovalent), methylene, isopropylidene (=C(CH3)2) and other alkylene groups (divalent).

[0065] Of these, Ar1 and Ar2 are preferably groups selected from the group consisting of the following.

[0066] [Chemistry 15] Of the resins shown in the above general formula (2), the resin shown in the following general formula (2-1) is preferred.

[0067] [Chemistry 16] The resins with heterocyclic structures in their main chains can be appropriately synthesized products, such as commercially available products. Examples include soluble polyimide resin KPI-MX300F (manufactured by Kawamura Sangyo Co., Ltd.), polyimides described in Japanese Patent Application Publication No. 2005-272655 (e.g., polyimides such as the polyimide in Example 1; polybenzoxazole such as Sumirezin Excel CRC-8300 (manufactured by Sumitomo Phenolic Resin Co., Ltd.); and polyimides such as polyimides polymerized by polymerizing bismaleimide MIR-3000-70MT (manufactured by Nippon Kayaku Co., Ltd.).

[0068] The content of the resin having heterocyclic structures in the main chain is not particularly limited and can be appropriately selected according to the purpose. It is preferably 10% by mass or more and 90% by mass or less relative to the total amount of the resin components, and more preferably 20% by mass or more and 80% by mass or less.

[0069] <<Other Resins>> Among the above-mentioned resin components, in addition to resins with heterocyclic structures in the main chain, other resins such as film-forming resins and thermosetting resins are preferred.

[0070] The other resins and curing agents mentioned above can be combined with the resins whose main chain has heterocyclic structures, and can be mixed as additives.

[0071] Here, when the resin with the main chain having heterocyclic structure has reactive functional groups such as cyclic ether groups and double bond groups, it is advantageous to obtain resin components and their cured products that achieve higher electrical connection reliability based on the combination reaction or cross-linking reaction with other resins.

[0072] -Film-forming resin- There are no particular limitations on the film-forming resins mentioned above, and appropriate selections can be made according to the purpose. Examples include phenoxy resins, acrylic resins, unsaturated polyester resins, saturated polyester resins, urethane resins, butadiene resins, polyamide resins, and polyolefin resins. One of the above film-forming resins can be used alone, or two or more can be used in combination. Among these, phenoxy resins are preferred in terms of thermal stability, film-forming properties, processability, and bonding reliability, while acrylic resins are preferred in terms of flexibility and adhesion.

[0073] Examples of phenoxy resins include, for instance, resins synthesized from bisphenol A and epichlorohydrin.

[0074] The phenoxy resins mentioned above can be appropriately synthesized products or commercially available products.

[0075] There are no particular limitations on the content of the above-mentioned film-forming resin, and it can be appropriately selected according to the purpose. Relative to the above-mentioned resin composition, it is preferably 0% by mass or more than 80% by mass, more preferably 20% by mass or more than 70% by mass, and even more preferably 30% by mass or more than 70% by mass.

[0076] -Thermosetting resin- There are no particular limitations on the thermosetting resins (thermosetting components) mentioned above, and appropriate selections can be made according to the purpose. For example, epoxy resins, free radical polymeric compounds, etc. can be cited.

[0077] --Epoxy Resin-- There are no particular limitations on the epoxy resins mentioned above, and appropriate selections can be made according to the purpose. For example, thermosetting epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic varnish type epoxy resin, and their modified epoxy resins can be used. One type can be used alone, or two or more types can be used in combination.

[0078] --Free radical polymers-- There are no particular limitations on the aforementioned free radical polymerizable compounds, and appropriate selections can be made according to the purpose. Examples include methacrylates, ethylacrylates, isopropylacrylates, isobutylacrylates, phosphate-containing acrylates, ethylene glycol diacrylates, diethylene glycol diacrylates, trimethylolpropane triacrylates, dimethyloltricyclodecane diacrylates, 1,4-butanediol tetraacrylates, 2-hydroxy-1,3-diacryloyloxypropane, 2,2-bis[4-(acryloyloxymethoxy)phenyl]propane, 2,2-bis[4-(acryloyloxyethoxy)phenyl]propane, dicyclopentenyl acrylates, tricyclodecyl acrylates, tri(acryloyloxyethyl)isocyanurate, carbamate acrylates, epoxy acrylates, etc. Furthermore, substances that make the aforementioned acrylates methacrylates can be used. One of these can be used alone, or two or more can be used in combination.

[0079] There are no particular limitations on the content of the aforementioned thermosetting resin, which can be appropriately selected according to the purpose. Relative to the aforementioned resin composition, it is preferably 0% by mass or more and 80% by mass or less, more preferably 20% by mass or more and 70% by mass or less, and even more preferably 30% by mass or more and 70% by mass or less.

[0080] <Other Ingredients> There are no particular restrictions on the other components mentioned above, and appropriate selections can be made according to the purpose. For example, curing agents, silane coupling agents, etc. can be mentioned.

[0081] <<Curing Agent>> As for the aforementioned curing agent, there are no particular limitations as long as it has the function of curing the aforementioned thermosetting resin by heat, and it can be appropriately selected according to the purpose. For example, cationic curing agents, free radical curing agents, etc. can be mentioned.

[0082] -Catonic curing agent- There are no particular limitations on the cationic curing agents mentioned above, and appropriate selections can be made according to the purpose. For example, sulfonium salts and sulfonium salts can be mentioned. Among these, aromatic sulfonium salts are preferred.

[0083] The above-mentioned cationic curing agent is preferably used in combination with the above-mentioned thermosetting resin, epoxy resin.

[0084] -Free radical curing agent- There are no particular limitations on the free radical curing agents mentioned above, and appropriate selection can be made according to the purpose. For example, organic peroxides can be cited.

[0085] The aforementioned free radical curing agent is preferably used in combination with the aforementioned free radical polymerizable compound, which is the aforementioned thermosetting resin.

[0086] The content of the curing agent is not particularly limited and can be appropriately selected according to the purpose. It is preferably 1 part to 10 parts by mass relative to 100 parts by mass of the resin component, and more preferably 3 parts to 7 parts by mass.

[0087] <<Silane Coupling Agents>> There are no particular limitations on the silane coupling agents mentioned above, and appropriate selection can be made according to the purpose. For example, epoxy silane coupling agents, acrylic silane coupling agents, thiol silane coupling agents, and amine silane coupling agents can be mentioned.

[0088] There are no particular restrictions on the content of the aforementioned silane coupling agent, and it can be appropriately selected according to the purpose.

[0089] [Anisotropic conductive adhesive film] The above-mentioned anisotropic conductive adhesive is suitable for use as an embodiment of anisotropic conductive adhesive film.

[0090] As an anisotropic conductive adhesive film, it can be a conductive material dispersion type film in which the conductive material is dispersed in the film-like resin component, or it can be a conductive material arrangement type film in which the conductive material is arranged in a single layer in the film-like resin component. Both are suitable for making anisotropic conductive connections between the terminals of the first circuit component and the terminals of the second circuit component.

[0091] The anisotropic conductive adhesive film described above is further preferably made of a peelable substrate.

[0092] There is no particular limitation on the average thickness of the anisotropic conductive adhesive film, and it can be appropriately selected according to the purpose. The average thickness of the anisotropic conductive adhesive is preferably 2μm to 50μm, more preferably 3μm to 40μm, and particularly preferably 3μm to 25μm.

[0093] Here, the average thickness mentioned above refers to the arithmetic mean of 10 measurements taken at any given location.

[0094] In the above-mentioned anisotropic conductive adhesive films that are of the conductive material arrangement type, there are no particular restrictions on the method of arranging the conductive materials, and appropriate selection can be made according to the purpose. For example, the method of using biaxial stretching operation for the unstretched polypropylene film in Example 1 of Patent No. 4789738; the method of using a mold disclosed in Japanese Patent Application Publication No. 2010-33793; etc.

[0095] In addition, regarding the degree of arrangement, it is preferable to consider the size of the connected objects, conductivity reliability, insulation, particle capture efficiency, etc., and arrange them in a single layer with two-dimensional isolation of about 1μm to 100μm.

[0096] <Peelable substrate> As the aforementioned peelable substrate, if it is a film that can be peeled off from the anisotropic conductive film during temporary adhesion, it can be used without particular restrictions.

[0097] Examples of such releaseable substrates include silicone films, fluorine films, PET (polyethylene terephthalate) treated with a release agent, PEN (polyethylene naphthalate) treated with a release agent, and glassine paper treated with a release agent.

[0098] Examples of release agents include silicone-based release agents and fluorinated release agents.

[0099] Among these, the preferred substrate is the one treated with a silicone-based release agent.

[0100] The aforementioned peelable substrate is disposed in contact with the aforementioned anisotropic conductive film.

[0101] The surface of the aforementioned release substrate preferably undergoes a demolding process on the side that is in contact with the aforementioned anisotropic conductive film, while the surface on the opposite side that is in contact with the aforementioned anisotropic conductive film may not undergo a demolding process.

[0102] The average thickness of the aforementioned peelable substrate is not particularly limited and can be appropriately selected according to the purpose, preferably 12μm to 75μm.

[0103] Here, figures are used to illustrate an example of the anisotropic conductive film of this embodiment.

[0104] Figure 1 This is a schematic cross-sectional view of an example of the anisotropic conductive film of this embodiment. Figure 1 The anisotropic conductive film 10 has a film-like anisotropic conductive adhesive 2 on a peelable substrate 1. The anisotropic conductive adhesive 2 is a conductive material dispersion film having a resin component 3 and a conductive material 4 dispersed in the resin component 3.

[0105] Figure 2 This is a schematic cross-sectional view of other examples of the anisotropic conductive film of this embodiment. Figure 3 AA' cross-sectional view. Figure 3 for Figure 2 BB' cross-sectional view. Figures 2-3 The anisotropic conductive film 20 has a film-like anisotropic conductive adhesive 2 on a peelable substrate 1. The anisotropic conductive adhesive 2 is a film containing a resin component 3 and conductive materials 4 arranged in a single layer within the resin component 3. The dimensions of the conductive materials 4 are approximately equal to the average thickness of the anisotropic conductive adhesive 2.

[0106] Figure 4This is a schematic cross-sectional view of another example of the anisotropic conductive film of this embodiment. Figure 4 Anisotropic conductive film 30 Figures 2-3 A variation of the anisotropic conductive film 20 is a film in which the approximately quadrilateral prism-shaped conductive material 4 is arranged in a single layer in the resin component 3, instead of a spherical conductive material 4. The arrangement pattern of the conductive material 4 is, as an example, 60° staggered.

[0107] The shape of the conductive material 4 is not particularly limited and can be appropriately selected according to the purpose. It is preferably spherical, ellipsoidal, cylindrical, elliptical, approximately quadrilateral, approximately equilateral triangle, approximately hexagonal, and other cylindrical shapes.

[0108] There are no particular restrictions on the arrangement pattern of the conductive material 4, and it can be appropriately selected according to the purpose. Preferably, the conductive materials are arranged in a single layer in a regular manner without contacting each other. For example, patterns such as 60° staggered, 45° staggered, squares side by side, regular hexagons staggered at 60°, equilateral triangles, and alternating quadrilaterals can be given.

[0109] Here, "60° staggered" means that, when viewed from above, the centers of each conductive material are multiple equilateral triangles, arranged in a pattern such that the vertices of equilateral triangles sharing each side are arranged in a pattern. "45° staggered" means that, when viewed from above, the centers of each conductive material are multiple right-angled equilateral triangles, arranged in a pattern such that the vertices of right-angled equilateral triangles sharing each side are arranged in a pattern.

[0110] The size of the conductive material 4 is not particularly limited and can be appropriately selected according to the purpose. It is more than 1 / 5 and less than 1 / 5 of the average thickness of the anisotropic conductive adhesive 2. When the anisotropic conductive film 20 or 30 is disposed between the terminals of the first circuit component and the terminals of the second circuit component, each conductive material 4 is exposed on each surface of the anisotropic conductive adhesive 2, which can efficiently perform anisotropic conductive connection. This is preferred.

[0111] in addition, Figure 2 and Figure 4 In this case, the size of the conductive material 4 is approximately equal to the average thickness of the anisotropic conductive adhesive 2. When the size of the conductive material 4 is smaller than the average thickness of the anisotropic conductive adhesive 2, it can be disposed on the opposite side of the peelable substrate 1 of the anisotropic conductive adhesive 2, or disposed inside the anisotropic conductive adhesive 2, and can be appropriately selected according to the intended purpose.

[0112] (Connecting structure) The connection structure of the present invention includes a first circuit component, a second circuit component, and the anisotropic conductive adhesive or anisotropic conductive film of the present embodiment described above, which anisotropically conductively connects the first circuit component and the second circuit component, and may further include other components as needed.

[0113] <Circuit Component 1, Circuit Component 2> As for the first circuit component and the second circuit component mentioned above, there are no particular limitations on whether they are circuit components with terminals that are objects of anisotropic conductive connections using the anisotropic conductive adhesive or anisotropic conductive film mentioned above. They can be appropriately selected according to the purpose. For example, examples include glass substrates with terminals, plastic substrates with terminals, IC (Integrated Circuit), TAB (Tape Automated Bonding) tape, Flex-on-Glass (Flexible Circuit Mounting Glass, FOG), Chip-on-Glass (Chip Mounting Glass, COG), Chip-on-Flex (Chip Mounting Flexible Circuit, COF), Flex-on-Board (Flexible Circuit Mounting Circuit Board, FOB), Flex-on-Flex (Flexible Circuit Mounting Flexible Circuit, FOF), liquid crystal panels, etc.

[0114] Examples of glass substrates with terminals include ITO (Indium Tin Oxide) glass substrates, IZO (Indium Zinc Oxide) glass substrates, and other patterned glass substrates. Among these, ITO glass substrates and IZO glass substrates are preferred.

[0115] There are no particular restrictions on the material and structure of the aforementioned plastic substrate with terminals, and appropriate selection can be made according to the purpose. For example, rigid substrates with terminals and flexible substrates with terminals can be cited.

[0116] Examples of such ICs include, for instance, the liquid crystal display (LCD) control IC chip used in a flat panel display (FPD).

[0117] The shape and size of the first and second circuit components are not particularly limited and can be appropriately selected according to the purpose.

[0118] The first circuit component and the second circuit component mentioned above may be the same circuit component or they may be different circuit components.

[0119] [Manufacturing method and connection method of the connecting structure] The manufacturing method of the connecting structure of this embodiment, and the connection method of connecting using the anisotropic conductive adhesive or anisotropic conductive film of this embodiment, are not particularly limited and can be appropriately selected according to the purpose. For example, it may include at least a first configuration step, a second configuration step, and a heating and pressing step, and can be further implemented as needed by including other steps such as a temporary pasting step.

[0120] The above connection method is a method for making anisotropic conductive connections between the terminals of the first circuit component and the terminals of the second circuit component.

[0121] There are no particular limitations on the first circuit component and the second circuit component described above, and they can be appropriately selected according to the purpose. For example, the first circuit component and the second circuit component described above in the description of the anisotropic conductive film of this embodiment are respectively given examples.

[0122] <First Configuration Process> As for the first configuration step described above, there are no particular limitations as to the step of connecting the anisotropic conductive film of this embodiment to the terminal of the first circuit component. The step can be appropriately selected according to the purpose.

[0123] <Second Configuration Process> As for the second configuration step described above, there are no particular restrictions on the method of configuring the second circuit component on the anisotropic conductive film in such a way that the terminals of the second circuit component are connected to the anisotropic conductive film. The method can be appropriately selected according to the purpose.

[0124] <Heating and Pressing Process> As for the above-mentioned heating and pressing process, if it is a process of heating and pressing the second circuit component by means of a heating and pressing component, there are no particular restrictions, and it can be appropriately selected according to the purpose.

[0125] As a heating and pressing component, examples include pressing components with a heating mechanism. As a pressing component with the heating mechanism, examples include heating tools.

[0126] There are no particular limitations on the heating temperature mentioned above, and it can be appropriately selected according to the purpose, preferably 150℃~200℃.

[0127] There are no particular limitations on the pressure used for the aforementioned pushing, and it can be appropriately selected according to the purpose, preferably 0.1MPa to 50MPa.

[0128] There are no particular restrictions on the heating and pressing time mentioned above, and it can be appropriately selected according to the purpose, for example, 0.5 seconds to 120 seconds.

[0129] <Temporary pasting procedure> As for the aforementioned temporary pasting process, if it is a process of heating and pressing the anisotropic conductive film at a temperature lower than the heating temperature in the aforementioned heating and pressing process after the aforementioned first configuration process, and pasting the anisotropic conductive film onto the aforementioned first circuit component, there are no particular restrictions, and it can be appropriately selected according to the purpose.

[0130] The aforementioned heating and pressing can be performed, for example, using a heated pressing member. Examples of such heated pressing members include pressing members with a heating mechanism. Examples of pressing members with a heating mechanism include heating tools.

[0131] When the anisotropic conductive film has the peelable substrate on the conductive material side, the temporary bonding process is preferably performed with the anisotropic conductive film having the peelable substrate, and after the temporary bonding process, the peelable substrate is peeled off from the anisotropic conductive film.

[0132] The heating temperature in the temporary bonding process described above is not particularly limited and can be appropriately selected according to the purpose, if it is lower than the heating temperature in the heating and pressing process described above. A temperature of 50°C to 110°C is preferred. The heating temperature is preferably the temperature at which the anisotropic conductive film has not yet cured.

[0133] The pressure used for pushing in the above-mentioned temporary pasting process is not particularly limited and can be appropriately selected according to the purpose, preferably 0.1MPa to 10MPa.

[0134] There are no particular restrictions on the heating and pressing time in the above-mentioned temporary pasting process, and it can be appropriately selected according to the purpose. For example, 0.5 seconds to 10 seconds can be used.

[0135] Example The following describes embodiments of the present invention, but the present invention is not limited by these embodiments.

[0136] (Example 1) <Preparation of Anisotropic Conductive Adhesives> A polyimide solution was prepared by dissolving a polyimide (the soluble polyimide of Example 1 in Japanese Patent Application Publication No. 2005-272655, a synthetic product thereof) in N-methylpyrrolidone (NMP) to a concentration of 15% by mass, which is a mixture of the resin shown in general formula (1-1) and the resin shown in general formula (1-2) below.

[0137] To 100 parts by weight of resin component, in which polyimide solution and epoxy resin (EXA-850CRP, manufactured by DIC Corporation) are mixed at a solids ratio of 50:50, 5 parts by weight of Curezol (2E4MZ, manufactured by Shikoku Kasei Corporation) as a curing agent are added, and the mixture is further mixed. The mixing is performed using a planetary mixer (AWATORI Rentaro ARE-312, manufactured by Thinky Corporation). To the resulting mixture, 50 parts by weight of Ni particles (3 μm in diameter, NIEJB-003-S, manufactured by Sekisui Chemicals Co., Ltd.) as a conductive material are added to 100 parts by weight of resin component, and the mixture is further mixed to disperse the conductive material, thus obtaining the anisotropic conductive adhesive of Example 1.

[0138] [Chemistry 17] Fabrication of anisotropic conductive films The obtained anisotropic conductive adhesive was coated onto a PET (polyethylene terephthalate) film (UH-4, average film thickness 50 μm, manufactured by Teijin Corporation) using a rod coater. The film was then heated at 80°C for 10 minutes in a drying oven to remove the solvent, resulting in the anisotropic conductive film of Example 1 with an average thickness of 15 μm.

[0139] (Example 2) In Example 1, the solid component ratio (mass ratio) of polyimide to epoxy resin was changed from 50:50 to 20:80. Otherwise, the same procedure as in Example 1 was followed to obtain the anisotropic conductive adhesive and anisotropic conductive film of Example 2.

[0140] (Example 3) In Example 1, the solid component ratio (mass ratio) of polyimide to epoxy resin was changed from 50:50 to 80:20. Otherwise, the same procedure as in Example 1 was followed to obtain the anisotropic conductive adhesive and anisotropic conductive film of Example 2.

[0141] (Example 4) In Example 1, the epoxy resin was replaced with an acrylic resin (trade name: ACMO, manufactured by KJ Chemical Co., Ltd.). Otherwise, the same procedure as in Example 1 was followed to obtain the anisotropic conductive adhesive and anisotropic conductive film of Example 4.

[0142] (Example 5) In Example 1, the polyimide was replaced with polybenzoxazole (Sumirezin Excel CRC-8300, manufactured by Sumitomo Phenolic Resin Co., Ltd.). Otherwise, the same procedure as in Example 1 was followed to obtain the anisotropic conductive adhesive and anisotropic conductive film of Example 5.

[0143] (Example 6) In Example 1, the polyimide was replaced with bismaleimide (MIR-3000-70MT, manufactured by Nippon Kayaku Co., Ltd.). Otherwise, the same procedure as in Example 1 was followed to obtain the anisotropic conductive adhesive and anisotropic conductive film of Example 5.

[0144] (Example 7) In Example 1, no conductive material was added. Otherwise, the same procedure as in Example 1 was followed to obtain an anisotropic conductive film intermediate with an average thickness of 4 μm.

[0145] Next, on the obtained anisotropic conductive film intermediate, Ni particles (3 μm in diameter, NIEJB-003-S, manufactured by Sekisui Chemicals Co., Ltd.) were arranged according to the operation disclosed in Japanese Patent Application Publication No. 2010-33793 to produce the anisotropic conductive film of Example 7.

[0146] (Comparative Example 1) In Example 1, the solid component ratio (mass ratio) of polyimide to epoxy resin was changed from 50:50 to 0:100. Otherwise, the same procedure as in Example 1 was followed to obtain the anisotropic conductive adhesive and anisotropic conductive film of Comparative Example 1.

[0147] <Evaluation> Using the obtained anisotropic conductive films, the "initial conductivity characteristics," "electrical connection reliability after temperature cycling," and "sealing performance" were evaluated through the following steps. The results are shown in Table 1.

[0148] <Initial Conduction Characteristics> <<Fabrication of Press-Bonded Laminates>> As the evaluation substrate, a flexible printed circuit board (FPC) with Cu / Ni / Au plated wiring (wire width: 25μm, and wire spacing: 25μm with a 50μm pitch) was used. An anisotropic conductive film was sandwiched between two evaluation substrates, and a heated bonding machine (BD-01 benchtop hot bonding device, manufactured by Ohashi Manufacturing Co., Ltd.) was used to heat and press the laminate at 2MPa and 180°C for 20 seconds to produce an evaluation laminate.

[0149] <<Evaluation of Initial Conductivity Characteristics>> For the obtained press-fit laminate, the initial on-resistance is measured by passing current through it.

[0150] Specifically, a digital multimeter (model number: Digital Multimeter 7555, manufactured by Yokogawa Electric Corporation) was used to measure the voltage when a current of 1mA flowed through the device using a 4-terminal method, thereby determining the resistance value. The resistance values ​​of 30 channels were measured, and the maximum resistance value was taken as the measured value. The following evaluation criteria were then used for evaluation.

[0151] [Evaluation Criteria] ○: The on-resistance is less than 1Ω.

[0152] △: On-resistance exceeds 1Ω but is less than 2Ω.

[0153] ×: On-resistance exceeds 2Ω.

[0154] In addition, a rating of "○" indicates that the on-resistance is sufficiently low, a rating of "△" indicates that it is practical, and a rating of "×" indicates that it is not practical.

[0155] <Electrical connection reliability after temperature cycling> <<Thermal Cycling Test>> The obtained press-fit laminate was placed in a highly accelerated life test apparatus (EHS-212MD, manufactured by ESPEC Corporation) and subjected to thermal cycling tests (500 cycles of 1 cycle: -55°C, 30 minutes and 125°C, 30 minutes) to obtain a press-fit laminate subjected to temperature cycling under load.

[0156] <<Electrical Connection Reliability>> In addition to using a press-fit laminate subjected to temperature cycling, the on-resistance was measured according to the above-mentioned <<Evaluation of Initial Conductivity>> and its evaluation criteria, and the evaluation was carried out.

[0157] <Seamlessness> The laminated material subjected to temperature cycling was inspected using an ultrasonic imaging device (SAT, FS300IIIHR, manufactured by Hitachi Power Solutions, Ltd.) to check for adhesion to the substrate and the presence or absence of voids. A 50MHz, 7mm probe was used on the copper side, and a 25MHz probe was used on the silicon side.

[0158] [Evaluation Criteria] 〇: The lifting, peeling, and voids from the substrate are less than 0.1% of the field of view, which is within the practical range.

[0159] ×: The lifting, peeling, and voids of the substrate account for more than 0.1% of the field of view, which is outside the practical range.

[0160] [Table 1] This international application claims priority based on Japanese Patent Application No. 2024-008455, filed January 24, 2024, and Japanese Patent Application No. 2025-003316, filed January 9, 2025, and incorporates the entire contents of Japanese Patent Application No. 2024-008455 and Japanese Patent Application No. 2025-003316 into this international application.

[0161] Explanation of symbols 1. Peelable substrate 2 Anisotropic conductive adhesive 3 Resin Components 4. Conductive materials 10 Anisotropic conductive films (dispersion type) 20, 30 anisotropic conductive films (alignment type)

Claims

1. An anisotropic conductive adhesive, characterized in that, Contains: resin components comprising a resin whose main chain has heterocyclic structures, and conductive materials.

2. The anisotropic conductive adhesive according to claim 1, The resin whose main chain has heterocyclic structures is represented by the following general formula (1) or the following general formula (2). In the general formula (1), X represents a group selected from the group consisting of the following, Ar1 and Ar2 each represent an aryl group having one or more benzene rings, and n represents an integer. In the general formula (2), Y represents the group consisting of the following components, Ar1 and Ar2 each represent an aryl group having one or more benzene rings, and n represents an integer. 。 3. The anisotropic conductive adhesive according to claim 1, The resin whose main chain has heterocyclic structures is represented by the following general formula (1) or the following general formula (2). In the general formula (1), X, Ar1, and Ar2 each represent a group selected from the group consisting of the following, and n represents an integer. In the general formula (2), Y, Ar1, and Ar2 each represent groups selected from the group consisting of the following, and n represents an integer. 。 4. The anisotropic conductive adhesive according to any one of claims 1 to 3, The content of the resin with heterocyclic structures in the main chain is more than 20% by mass and less than 80% by mass relative to the total amount of the resin components.

5. The anisotropic conductive adhesive according to any one of claims 1 to 4, The resistivity of the conductive material is 120 × 10⁻⁶. -8 [Ω [m] and below.

6. The anisotropic conductive adhesive according to any one of claims 1 to 5, The conductive material comprises at least one selected from Au, Ag, Sn, Pb, Cu, Al, Ni, and Fe.

7. The anisotropic conductive adhesive according to any one of claims 1 to 6, The conductive material comprises at least one selected from metal particles, alloy particles, and core-shell particles.

8. The anisotropic conductive adhesive according to any one of claims 1 to 7, further comprising a curing agent.

9. The anisotropic conductive adhesive according to any one of claims 1 to 8, further comprising other resins.

10. The anisotropic conductive adhesive according to any one of claims 1 to 9, wherein it is an anisotropic conductive adhesive film.

11. The anisotropic conductive adhesive according to any one of claims 1 to 10, wherein the conductive material is arranged in a single layer in the film-like resin component as an anisotropic conductive adhesive film.

12. A connecting structure, characterized in that, have: First circuit component, The second circuit component, and An anisotropic conductive adhesive according to any one of claims 1 to 11 for anisotropically conductively connecting the first circuit component and the second circuit component.

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