Method for manufacturing a connecting body and an adhesive film

Abstract

A method for producing a connector, the method comprising a step for electrically connecting a second electronic member having a second electrode to a first electronic member having a first electrode through an adhesive film, wherein the first electronic member has a surface with protrusions and recesses, the first electrode is provided at a recessed portion of the surface having protrusions and recesses, the second electrode has a generally flat surface having an area larger than that of the first electrode, the adhesive film contains first conductive particles that are dendrite-like and second conductive particles that are other than the first conductive particles and that each have a non-conductive core and a conductive layer provided on the core, the average particle size of the second conductive particles is greater than or equal to the depth of the recessed portion, and, in said step, the adhesive film is disposed between the first and second electronic members and the second electronic member is attached to the first electronic member through application of pressure so that the generally flat surface of the second electrode is electrically connected to the first electrode.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a connection body and an adhesive film. [Background technology]

[0002] In recent years, various adhesives have been used in fields such as semiconductors and liquid crystal displays to fix electronic components and connect circuits. In these applications, electronic components, circuits, and other electronic components are becoming increasingly dense and precise, requiring adhesives to have higher levels of performance. Furthermore, because the appropriate adhesive composition may vary depending on the electronic components to be connected, it is necessary to consider the composition, characteristics, and other aspects of the electronic components when selecting an adhesive.

[0003] For example, Patent Document 1 discloses a method for manufacturing a connector using an anisotropic conductive adhesive that ensures conductivity even for electrode terminals with an oxide film formed on the surface and also provides insulation between adjacent wiring, and aims to provide an anisotropic conductive adhesive. The anisotropic conductive adhesive has a first conductive adhesive layer having a binder resin and first conductive particles dispersed in the binder resin, and a second conductive adhesive layer laminated on one side of the first conductive adhesive layer and having second conductive particles dispersed in the binder resin, the second conductive particles having a particle diameter smaller than the particle diameter of the first conductive particles. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-182823 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to obtain a connector with excellent appearance and low resistance when connecting an electronic component having flat electrodes to an electronic component having an uneven surface with electrodes provided in the recesses of the uneven surface.

Means for Solving the Problem

[0006] According to the study by the present inventors, when connecting an electronic member having a flat electrode to an electronic member having concavo-convexities on its surface and having an electrode provided in the concave portion of the concavo-convexities, not any adhesive can be suitably used. In order to solve the above problems, that is, in order to obtain a connection body excellent in appearance (specifically, generation of bubbles in the concave portion is suppressed) and having low resistance, it is necessary to use a specific adhesive. Here, the appearance and resistance of the connection body mean the appearance and resistance as so-called initial characteristics immediately after the connection body is obtained.

[0007] One aspect of the present invention is a method for manufacturing a connection body, including a step of electrically connecting a second electronic member having a second electrode to a first electronic member having a first electrode via an adhesive film, wherein the first electronic member has a concavo-convex surface, the first electrode is provided in a concave portion of the concavo-convex surface, the second electrode is an electrode having a substantially flat surface with an area larger than the area of the first electrode, the adhesive film contains first conductive particles which are dendrite-shaped conductive particles and second conductive particles which are conductive particles other than the first conductive particles and which have a non-conductive core body and a conductive layer provided on the core body, the average particle diameter of the second conductive particles is equal to or more than the depth of the concave portion, and in the above step, the adhesive film is disposed between the first electronic member and the second electronic member, and the second electronic member is pressure-bonded to the first electronic member so that the substantially flat surface of the second electrode is electrically connected to the first electrode.

[0008] Another aspect of the present invention is an adhesive film containing first conductive particles which are dendritic conductive particles and second conductive particles which are conductive particles other than the first conductive particles and which have a non-conductive core body and a conductive layer provided on the core body. The adhesive film is used for electrical connection between a first electronic member having a first electrode and a second electronic member having a second electrode. The first electronic member has a concavo-convex surface, and the first electrode is provided in a concave portion of the concavo-convex surface. The average particle diameter of the second conductive particles is equal to or greater than the depth of the concave portion. The second electrode is an electrode having a substantially flat surface with an area larger than the area of the first electrode. In the electrical connection, the substantially flat surface of the second electrode is electrically connected to the first electrode.

[0009] The thickness of the adhesive film may be 15 μm or more. The thickness of the adhesive film may be equal to or greater than the depth of the concave portion. The average particle diameter of the second conductive particles may be 2.5 times or less the depth of the concave portion. The thickness of the adhesive film may be 1.2 times or more and 2.0 times or less the average particle diameter of the second conductive particles.

Advantages of the Invention

[0010] According to the present invention, when connecting an electronic member having a flat electrode to an electronic member having concavo-convexities on its surface and an electrode provided in a concave portion of the concavo-convexities, a connection body excellent in appearance and having low resistance can be obtained.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. Unless otherwise specified, the materials exemplified below may be used alone or in combination of two or more. The content of each component in the composition means the total amount of the plurality of substances corresponding to each component in the composition when there are a plurality of substances corresponding to each component in the composition. In addition, the numerical range indicated by using "~" indicates a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively. In the numerical ranges described step by step in this specification, the upper limit value or the lower limit value of a certain step numerical range may be replaced with the upper limit value or the lower limit value of another step numerical range. Further, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. In addition, the individually described upper limit value and lower limit value can be arbitrarily combined. Further, "A or B" means that either one of A and B may be included, or both may be included.

[0013] One embodiment of the present invention is a method for manufacturing a connection body, which includes a step (connection step) of electrically connecting a second electronic member to a first electronic member via an adhesive film. FIG. 1 is a schematic cross-sectional view showing one embodiment of the method for manufacturing a connection body. As shown in FIG. 1, in this manufacturing method, first, a first electronic member 1, a second electronic member 2, and an adhesive film 3 are prepared.

[0014] The first electronic member 1 includes a first substrate 4, an insulating layer 5 provided on one surface of the first substrate 4, and a first electrode 6. The surface of the first electronic member 1 (the surface on the side connected to the second electronic member 2) is uneven due to the insulating layer 5. That is, in the first electronic member 1, a plurality of insulating layers 5 provided convexly on the first substrate 4 constitute convex portions 1a, and the plurality of insulating layers 5 are provided spaced apart from each other, so that the gaps between the plurality of insulating layers 5 constitute concave portions 1b. The first electrode 6 is provided in the concave portion 1b on the first substrate 4.

[0015] The length L1 of the recess 1b (the length in the direction parallel to the surface of the first substrate 4 on which the insulating layer 5 and the first electrode 6 are provided) may be, for example, 25 μm or more and may be 3 mm or less. The depth D of the recess 1b (the distance from the surface of the first electrode 6 to the upper surface of the insulating layer 5) may be, for example, 5 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, or 25 μm or more, and may be 40 μm or less.

[0016] The first substrate 4 may be, for example, a substrate formed of glass, ceramic, polyimide, polycarbonate, polyester, polyethersulfone, or the like. The insulating layer 5 may be, for example, a layer formed of a solder resist or a coverlay. The first electrode 6 may be, for example, an electrode formed of gold, silver, copper, tin, aluminum, ruthenium, rhodium, palladium, osmium, iridium, platinum, indium tin oxide (ITO), or the like. The thickness of the first electrode 6 may be, for example, 5 μm or more, 10 μm or more, or 20 μm or more, and may be 200 μm or less, 100 μm or less, or 50 μm or less.

[0017] The second electronic component 2 includes a second substrate 7 and a second electrode 8 provided on one surface of the second substrate 7. The second substrate 7 may be, for example, a substrate formed of polyimide, polycarbonate, polyester, polyethersulfone, or the like. The second electrode 8 may be, for example, an electrode formed of gold, silver, copper, tin, aluminum, ruthenium, rhodium, palladium, osmium, iridium, platinum, indium tin oxide (ITO), or the like. The thickness of the second electrode 8 may be, for example, 5 μm or more, 10 μm or more, or 20 μm or more, and may be 200 μm or less, 100 μm or less, or 50 μm or less.

[0018] The second electrode 8 has a substantially flat surface 8a. The area of the substantially flat surface 8a of the second electrode 8 is larger than the area of the first electrode 6. That is, the length L2 of the substantially flat surface 8a of the second electrode 8 (the length in the direction parallel to the surface of the second substrate 7 on which the second electrode 8 is provided) is longer than the length L1 of the first electrode 6.

[0019] In one embodiment, the adhesive film 3 is composed of an adhesive layer containing an adhesive component 9, and first conductive particles 10 and second conductive particles 11 dispersed in the adhesive component 9.

[0020] The adhesive component 9 is made of, for example, a material that exhibits curability by heat or light, and may be an epoxy-based adhesive, a radical-curing adhesive, a polyurethane, a thermoplastic adhesive containing polyvinyl ester, etc. Since the adhesive component 9 is excellent in heat resistance and moisture resistance after adhesion, it may be made of a crosslinkable material. The epoxy-based adhesive contains an epoxy resin, which is a thermosetting resin, as a main component. The adhesive component 9 may be an epoxy-based adhesive in terms of being curable in a short time, having good connection workability, and excellent adhesiveness. The radical-curing adhesive has characteristics such as being more excellent in curability at low temperature and in a short time than the epoxy-based adhesive, and is thus appropriately used according to the application.

[0021] The epoxy-based adhesive contains, for example, an epoxy resin (a thermosetting material) and a curing agent, and may further contain a thermoplastic resin, a coupling agent, a filler, etc. as necessary.

[0022] Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, alicyclic epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, aliphatic chain epoxy resin, etc. These epoxy resins may be halogenated, hydrogenated, or may have a structure in which an acryloyl group or a methacryloyl group is added to the side chain. These epoxy resins are used alone or in combination of two or more.

[0023] The curing agent is not particularly limited as long as it can cure the epoxy resin. For example, anionic polymerization catalyst-type curing agents, cationic polymerization catalyst-type curing agents, polyaddition-type curing agents, etc. can be mentioned. Among these, an anionic or cationic polymerization catalyst-type curing agent may be used because it is excellent in rapid curing and does not require consideration of chemical equivalence.

[0024] Examples of the anionic or cationic polymerization catalyst-type curing agent include imidazole, hydrazide, boron trifluoride-amine complex, onium salts (such as aromatic sulfonium salts, aromatic diazonium salts, aliphatic sulfonium salts, etc.), amine imide, diaminomaleonitrile, melamine and its derivatives, salts of polyamines, dicyandiamide, etc. Modified products of these can also be used. Examples of the polyaddition-type curing agent include polyamines, polymercaptans, polyphenols, acid anhydrides, etc.

[0025] From the viewpoint of being able to extend the pot life, these curing agents may be latent curing agents encapsulated with polymer substances such as polyurethane-based and polyester-based, metal thin films such as nickel and copper, and inorganic substances such as calcium silicate. The curing agent is used singly or in combination of two or more.

[0026] The content of the curing agent may be 0.05 to 20 parts by mass with respect to 100 parts by mass of the total amount of the thermosetting material and the thermoplastic resin blended as required.

[0027] The radical-curing type adhesive contains, for example, a radically polymerizable material and a radical polymerization initiator (also called a curing agent), and may further contain a thermoplastic resin, a coupling agent, a filler, etc. as required.

[0028] As the radical polymerizable material, for example, any substance having a functional group polymerizable by radicals can be used without particular limitation. Specifically, for example, radical polymerizable materials such as acrylate compounds (including corresponding methacrylate compounds; the same shall apply hereinafter), acryloxy compounds (including corresponding methacryloxy compounds; the same shall apply hereinafter), maleimide compounds, citraconimide resins, nadimide resins, etc. can be mentioned. These radical polymerizable materials may be in the state of monomers or oligomers, or may be in the state of a mixture of monomers and oligomers.

[0029] Examples of the acrylate compound include methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, 2-hydroxy-1,3-diacryloxypropane, 2,2-bis[4-(acryloxymethoxy)phenyl]propane, 2,2-bis[4-(acryloxypolyethoxy)phenyl]propane, dicyclopentenyl acrylate, tricyclodecanyl acrylate, tris(acryloyloxyethyl) isocyanurate, urethane acrylate, phosphate ester diacrylate, etc.

[0030] The radical polymerizable material such as an acrylate compound may be used together with a polymerization inhibitor such as hydroquinone or methyl ether hydroquinone if necessary. From the viewpoint of improving heat resistance, the radical polymerizable material such as an acrylate compound may have at least one substituent such as a dicyclopentenyl group, a tricyclodecanyl group, or a triazine ring. The radical polymerizable material other than the acrylate compound may be, for example, a compound described in International Publication No. 2009 / 063827. The radical polymerizable material is used alone or in combination of two or more.

[0031] As the radical polymerization initiator, for example, any compound that decomposes upon heating or irradiation with light to generate free radicals can be used without particular limitation. Specifically, for example, peroxide compounds, azo compounds, etc. can be mentioned. These compounds are appropriately selected depending on the target connection temperature, connection time, pot life, etc.

[0032] More specifically, as the radical polymerization initiator, examples include diacyl peroxide, peroxydicarbonate, peroxyester, peroxyketal, dialkyl peroxide, hydroperoxide, silyl peroxide, etc. The radical polymerization initiator may be peroxyester, dialkyl peroxide, hydroperoxide, silyl peroxide, etc., and may be peroxyester in terms of obtaining high reactivity. These radical polymerization initiators may be, for example, the compounds described in International Publication No. 2009 / 063827. The radical polymerization initiator is used alone or in combination of two or more.

[0033] The content of the radical polymerization initiator may be 0.1 part by mass or more and may be 10 parts by mass or less with respect to 100 parts by mass in total of the radical polymerizable material and the thermoplastic resin blended as necessary.

[0034] The thermoplastic resin blended as necessary in the epoxy-based adhesive and the radical-curable adhesive, for example, facilitates the molding of the adhesive into a film shape. Examples of the thermoplastic resin include phenoxy resin, polyvinyl formal resin, polystyrene resin, polyvinyl butyral resin, polyester resin, polyamide resin, xylene resin, polyurethane resin, polyester urethane resin, phenol resin, terpene phenol resin, etc. The thermoplastic resin may be, for example, the compounds described in International Publication No. 2009 / 063827. The thermoplastic resin may be phenoxy resin because of its excellent adhesiveness, compatibility, heat resistance, mechanical strength, etc. The thermoplastic resin is used alone or in combination of two or more.

[0035] When the thermoplastic resin is incorporated into an epoxy adhesive, its content may be 5 parts by mass or more and 80 parts by mass or less based on 100 parts by mass of the total amount of the thermoplastic resin and the thermosetting material. When the thermoplastic resin is incorporated into a radical-curing adhesive, its content may be 5 parts by mass or more and 80 parts by mass or less based on 100 parts by mass of the total amount of the thermoplastic resin and the radically polymerizable material.

[0036] As another example of the adhesive component 9, a heat-radical-curing adhesive containing a thermoplastic resin, a radically polymerizable material that is liquid at 30°C, and a radical polymerization initiator can be mentioned. The heat-radical-curing adhesive has a lower viscosity compared to the above-described adhesives. The content of the radically polymerizable material in the heat-radical-curing adhesive may be 20 parts by mass or more, 30 parts by mass or more, or 40 parts by mass or more, and may be 80 parts by mass or less based on 100 parts by mass of the total amount of the thermoplastic resin and the radically polymerizable material.

[0037] The adhesive component 9 may be an epoxy adhesive containing a thermoplastic resin, a thermosetting material containing an epoxy resin that is liquid at 30°C, and a curing agent. In this case, the content of the epoxy resin in the epoxy adhesive may be 20 parts by mass or more, 30 parts by mass or more, or 40 parts by mass or more, and may be 80 parts by mass or less based on 100 parts by mass of the total amount of the thermoplastic resin and the thermosetting material.

[0038] The content of the adhesive component 9 in the adhesive film 3 (the volume ratio of the adhesive component 9 in the adhesive film 3) may be, for example, 55% by volume or more or 65% by volume or more, and may be 95% by volume or less or 85% by volume or less based on the total volume of the adhesive film 3.

[0039] The first conductive particle 10 exhibits a dendrite shape (also called a dendritic shape), and includes a single main axis and a plurality of branches that branch two-dimensionally or three-dimensionally from the main axis. The first conductive particle 10 may be formed of a metal such as copper or silver, and may be, for example, silver-coated copper particles in which copper particles are coated with silver.

[0040] The first conductive particles 10 may be known ones. Specifically, for example, they can be obtained as ACBY-2 (Mitsui Mining & Smelting Co., Ltd.), CE-1110 (Fukuda Metal Foil & Powder Co., Ltd.), #FSP (JX Metals Co., Ltd.), #51-R (JX Metals Co., Ltd.), etc. Alternatively, the first conductive particles 10 can also be manufactured by known methods (for example, the method described in International Publication No. 2014 / 021037).

[0041] The content of the first conductive particles 10 in the adhesive film 3 may be 5% by volume or more, 6% by volume or more, 7% by volume or more, 8% by volume or more, 9% by volume or more, 10% by volume or more from the viewpoint of further reducing the resistance of the connector based on the total volume of the adhesive film 3. From the viewpoint of improving the adhesive strength of the adhesive film, it may be 30% by volume or less, 25% by volume or less, 22% by volume or less, 20% by volume or less, 18% by volume or less, 15% by volume or less.

[0042] The second conductive particles 11 have a non-conductive core body and a conductive layer provided on the core body. The core body is formed of a non-conductive material such as glass, ceramic, resin, etc., and may be formed of resin. Examples of the resin include acrylic resin, styrene resin, silicone resin, polybutadiene resin, or a copolymer of monomers constituting these resins. The average particle diameter of the core body is appropriately selected so that the average particle diameter of the second conductive particles 11 falls within the range described later.

[0043] The conductive layer is formed of, for example, gold, silver, copper, nickel, palladium, or an alloy thereof. The conductive layer may contain at least one selected from gold, nickel, and palladium, may contain gold or palladium, and may contain gold from the viewpoint of excellent conductivity. The conductive layer is formed, for example, by plating the above metal on the core body. The thickness of the conductive layer may be, for example, 10 nm or more and 400 nm or less.

[0044] The average particle diameter of the second conductive particles 11 may be 10 μm or more, or 20 μm or more, and a conductive path can be suitably formed in the concave portion 1b of the first electronic member 1. From the viewpoint of suppressing deterioration of the appearance and resistance value even when the connector is placed at high or low temperatures, it may be 25 μm or more, may be 27 μm or more, or may be 30 μm or more. The average particle diameter of the second conductive particles 11 may be 50 μm or less, may be 40 μm or less, or may be 30 μm or less from the viewpoint of suitably thinning the adhesive film 3. The average particle diameter of the second conductive particles 11 and the core body constituting the same is measured by a particle size distribution measuring device (Microtrac (product name, Nikkiso Co., Ltd.)) using the laser diffraction / scattering method.

[0045] The average particle diameter of the second conductive particles 11 is equal to or greater than the depth D of the concave portion 1b from the viewpoint of obtaining a connector with excellent appearance and low resistance. From the viewpoint of more easily obtaining the effect, it may be 1.1 times or more, or 1.2 times or more the depth D of the concave portion 1b. The average particle diameter of the second conductive particles 11 may be 5 μm or more, may be 10 μm or more, or may be 20 μm or more. The average particle diameter of the second conductive particles 11 may be 100 μm or less, may be 60 μm or less, or may be 60 μm or less. From the viewpoint of obtaining a connector with excellent appearance and low resistance, it may be 2.5 times or less, 2.0 times or less, 1.7 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, or 1.2 times or less the depth D of the concave portion 1b.

[0046] The content of the second conductive particles 11 in the adhesive film 3 (the volume ratio of the second conductive particles 11 in the adhesive film 3) may be 1% by volume or more, may be 2% by volume or more, may be 3% by volume or more, may be 5% by volume or more, may be 20% by volume or less, may be 10% by volume or less, may be 8% by volume or less, or may be 5% by volume or less based on the total volume of the adhesive film 3.

[0047] The thickness of the adhesive film 3 is such that the recess 1b in the first electronic member 1 can be suitably filled with the adhesive component 9 or the like, and from the viewpoint of suppressing deterioration of the appearance and resistance value even when the connector is placed at high or low temperatures, it may be 15 μm or more, it may be 20 μm or more, it may be 25 μm or more, it may be 30 μm or more, it may be 35 μm or more, or it may be 40 μm or more. From the same viewpoint, the thickness of the adhesive film 3 may be equal to or greater than the depth D of the recess 1b, or may be 1.1 times or more, or 1.2 times or more the depth D of the recess 1b.

[0048] The thickness of the adhesive film 3 may be, for example, 70 μm or less, 60 μm or less, or 50 μm or less. The thickness of the adhesive film 3 may be, for example, 2.5 times or less, 2.0 times or less, 1.7 times or less, or 1.5 times or less the depth D of the recess 1b.

[0049] <t From the viewpoint of excellent appearance and easier obtaining of a low-resistance connector, and suppressing deterioration of the appearance and resistance value even when the connector is placed at high or low temperatures, the thickness of the adhesive film 3 may be 1.0 times or more, 1.1 times or more, or 1.2 times or more the average particle diameter of the second conductive particles, and may be 2.0 times or less, 1.8 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, or 1.3 times or less the average particle diameter of the second conductive particles.

[0050] In the connection process, the adhesive film 3 is disposed between the first electronic member 1 and the second electronic member 2, and the second electronic member 2 is pressure-bonded to the first electronic member 1. Specifically, pressure is applied and heating is performed in the direction of arrow X in FIG. 1 (the stacking direction of the first electronic member 1, the adhesive film 3, and the second electronic member 2) to the second electronic member 2 so that the substantially flat surface 8a of the second electrode 8 is electrically connected to the first electrode 6. The heating temperature may be, for example, 50°C or more and may be 190°C or less. The pressure may be, for example, 0.1 MPa or may be 30 MPa. The time for performing these heating and pressurization may be, for example, 0.5 seconds or more and may be 120 seconds or less.

[0051] As described above, a method for manufacturing a connector according to an embodiment includes a step of electrically connecting a second electronic member having a second electrode to a first electronic member having a first electrode via an adhesive film. The method for manufacturing a connector is such that the first electronic member has a concavo-convex surface, the first electrode is provided in a concave portion of the concavo-convex surface, the second electrode is an electrode having a substantially flat surface with an area larger than that of the first electrode, the adhesive film contains first conductive particles that are dendritic conductive particles and second conductive particles that are conductive particles other than the first conductive particles and have a non-conductive core body and a conductive layer provided on the core body, the average particle diameter of the second conductive particles is equal to or greater than the depth of the concave portion, and in the step, the adhesive film is disposed between the first electronic member and the second electronic member, and the second electronic member is pressure-bonded to the first electronic member so that the substantially flat surface of the second electrode is electrically connected to the first electrode.

[0052] Further, an adhesive film according to an embodiment contains first conductive particles that are dendritic conductive particles and second conductive particles that are conductive particles other than the first conductive particles and have a non-conductive core body and a conductive layer provided on the core body. The adhesive film is used for an electrical connection between a first electronic member having a first electrode and a second electronic member having a second electrode. The first electronic member has a concavo-convex surface, the first electrode is provided in a concave portion of the concavo-convex surface, the average particle diameter of the second conductive particles is equal to or greater than the depth of the concave portion, the second electrode is an electrode having a substantially flat surface with an area larger than that of the first electrode, and in the electrical connection, the substantially flat surface of the second electrode is electrically connected to the first electrode.

[0053] By the above manufacturing method, a connection body is obtained. The connection body includes a first substrate 4, a first electronic member 1 having an insulating layer 5 and a first electrode 6 provided on the first substrate 4, a second substrate 7, and a second electronic member 2 having a second electrode 8 provided on the second substrate 7, and a connection member that electrically connects the first electrode 6 and the second electrode 8 to each other. The connection member includes a cured product of an adhesive component 9 and first conductive particles 10 and second conductive particles 11 dispersed in the cured product. That is, the connection member is obtained by curing the above-described adhesive film 3.

Example

[0054] Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to the following examples.

[0055] (Preparation of Adhesive Solution) 50 g of phenoxy resin (manufactured by Union Carbide Corporation, product name: PKHC, weight average molecular weight: 45,000) was dissolved in a mixed solvent of toluene (boiling point: 110.6 °C) and ethyl acetate (boiling point: 77.1 °C) (toluene:ethyl acetate = 1:1 by mass ratio) to obtain a phenoxy resin solution having a solid content of 40% by mass. To this phenoxy resin solution, as a radical polymerizable material, urethane acrylate (manufactured by Negami Kogyo Co., Ltd., product name: UN7700) and phosphate ester dimethacrylate (manufactured by Kyoeisha Chemical Co., Ltd., product name: Light Ester P-2M), and as a curing agent, 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane (manufactured by NOF Corporation, product name: Perhexa TMH) were blended at a solid mass ratio of phenoxy resin:urethane acrylate:phosphate ester dimethacrylate:curing agent = 10:10:3:2 to obtain an adhesive solution.

[0056] (First Conductive Particles) As the first conductive particles, dendritic conductive particles (silver-coated copper particles, manufactured by Mitsui Mining & Smelting Co., Ltd., product name: ACBY-2) were used.

[0057] (Production of Second Conductive Particles a) First, benzoyl peroxide was added as a polymerization initiator to a mixed solution of divinylbenzene, styrene monomer, and butyl methacrylate, and the mixture was heated with high-speed and uniform stirring to carry out a polymerization reaction to obtain a fine particle dispersion. The fine particle dispersion was filtered and dried under reduced pressure to obtain a block body, which is an aggregate of fine particles. Further, the block body was pulverized to produce a core body (resin particles).

[0058] Next, a palladium catalyst (manufactured by Muromachi Technos Co., Ltd., product name: MK-2605) was supported on the surface of the above core body, and the core body activated with an accelerator (manufactured by Muromachi Technos Co., Ltd., product name: MK-370) was put into a mixed solution of an aqueous nickel sulfate solution, an aqueous sodium hypophosphite solution, and an aqueous sodium tartrate solution heated to 60°C to perform a pre-step for electroless plating. The mixture was stirred for 20 minutes, and it was confirmed that the evolution of hydrogen stopped. Next, a mixed solution of nickel sulfate, sodium hypophosphite, sodium citrate, and a plating stabilizer was added, and the mixture was stirred until the pH was stabilized, and a post-step for electroless plating was performed until the evolution of hydrogen stopped. Subsequently, the plating solution was filtered, the filtrate was washed with water, and then dried in a vacuum dryer at 80°C to produce second conductive particles a plated with nickel. The average particle size of the second conductive particles a was 30 μm, and the thickness of the conductive layer was 150 nm.

[0059] (Production of second conductive particles b) Second conductive particles b were obtained in the same manner as the second conductive particles a except that the particle size of the core body was changed. The average particle size of the second conductive particles b was 20 μm, and the thickness of the conductive layer was 100 nm.

[0060] (Production of second conductive particles c) Second conductive particles c were obtained in the same manner as the second conductive particles a except that the particle size of the core body was changed. The average particle size of the second conductive particles c was 10 μm, and the thickness of the conductive layer was 100 nm.

[0061] (Production of second conductive particles d) The second conductive particle d was obtained in the same manner as the second conductive particle a, except that the particle size of the core was changed. The average particle size of this second conductive particle d was 40 μm, and the thickness of the conductive layer was 100 nm.

[0062] (Preparation of the second conductive particle e) The second conductive particle e was obtained in the same manner as the second conductive particle a, except that the particle size of the core was changed. The average particle size of this second conductive particle e was 60 μm, and the thickness of the conductive layer was 100 nm.

[0063] (Preparation of the adhesive film) The first conductive particle and the second conductive particle were dispersed in the above adhesive solution so that the contents of the first conductive particle and the second conductive particle in the obtained adhesive film were the amounts shown in Table 1, to obtain a mixed solution. The obtained mixed solution was applied onto a fluororesin film with a thickness of 80 μm and dried with hot air at 70 °C for 10 minutes to remove the solvent, thereby obtaining each adhesive film with the thickness shown in Table 1 formed on the fluororesin film.

[0064] Each of the adhesive films was used to conduct the following evaluations. The results are shown in Table 1.

[0065] [Evaluation of initial characteristics] (Appearance) A sample 20 for appearance evaluation as shown in FIG. 2 was prepared. Note that FIG. 2(a) is a top view of the sample 20 for appearance evaluation, and FIG. 2(b) is a cross-sectional view taken along line IIb-IIb of FIG. 2(a).

[0066] Specifically, first, one of the polyimide films 22 (size: 25 mm × 25 mm, thickness: 10 μm, 20 μm, 25 μm, 35 μm, or 50 μm) with different thicknesses was placed on a slide glass 21 (size: 26 mm × 76 mm, thickness: 1 mm). A slit (recess) 22a (size: 20 mm × 0.5 mm, depth: 10 μm, 20 μm, 25 μm, 35 μm, or 50 μm) was formed in the approximate center of the polyimide film 22. Next, an aluminum foil 24 (size: 15 mm × 20 mm, thickness: 25 μm) was connected on the polyimide film 22 through each of the obtained adhesive films 23 (size: 15 mm × 3 mm).

[0067] For each of the obtained appearance evaluation samples 20, the inside of the slit 22a of the polyimide film 22 was observed from the slide glass 21 side (in the direction of arrow Y in Fig. 2(b)) with an optical microscope (in a field of view where the entire slit 22a can be observed), and the presence or absence of air bubbles in the slit 22a was confirmed. The appearance was evaluated as follows according to the presence or absence (number) of air bubbles of 50 μm or more. If the evaluation is A or B, it can be said that the appearance is excellent. A: No air bubbles of φ50 μm or more B: The number of air bubbles of φ50 μm or more is 1 - 2 C: The number of air bubbles of φ50 μm or more is 3 or more

[0068] <Resistance> A resistance measurement sample 30 as shown in Fig. 3 was prepared. Fig. 3(a) is a top view of the resistance measurement sample 30, and Fig. 3(b) is a cross-sectional view taken along line IIIb-IIIb of Fig. 3(a).

[0069] Specifically, first, one of the polyimide films 22 (size: 25 mm × 25 mm, thickness: 10 μm, 20 μm, 25 μm, 35 μm, or 50 μm) with different thicknesses was placed on a copper foil 31 (size: 35 mm × 35 mm, thickness: 25 μm). Note that a slit 32a (size: 20 mm × 0.5 mm, depth: 10 μm, 20 μm, 25 μm, 35 μm, or 50 μm) was formed in the approximate center of the polyimide film 32. Next, an aluminum foil 34 (size: 15 mm × 20 mm, thickness: 25 μm) was connected via each of the obtained adhesive films 33 (size: 15 mm × 3 mm) on the polyimide film 32.

[0070] For each of the obtained samples 30 for resistance measurement, the current and voltage between the copper foil 31 and the aluminum foil 34 were measured with an ammeter A and a voltmeter V, respectively, and the resistance value was calculated.

[0071] [Evaluation of Characteristics after Cycle Test] Each of the appearance evaluation sample 20 and the resistance measurement sample 30 prepared as described above was subjected to a cycle test using ESPEC TSA - 43EL, where it was held at - 20°C for 30 minutes, heated to 100°C over 10 minutes, held at 100°C for 30 minutes, and cooled to - 20°C over 10 minutes, and this heat cycle was repeated 250 times. For each of the appearance evaluation sample 20 and the resistance measurement sample 30 after the cycle test, the appearance was evaluated and the resistance was measured in the same manner as above.

[0072] [Evaluation of Adhesive Strength] An aluminum foil (size: 15 mm × 20 mm, thickness: 25 μm) was connected via each of the obtained adhesive films (size: 15 mm × 3 mm) on a copper foil (size: 40 mm × 15 mm, thickness: 25 μm). Using a Tensilon UTM - 4 manufactured by Toyo Baldwin Co., Ltd., in accordance with JIS Z0237, the adhesive strength of the connection body was measured by the 90 - degree peel method under the conditions of a peel speed of 50 mm / min and 25°C.

[0073]

Table 1

[0074]

Table 2

Explanation of Symbols

[0075] 1…First electronic component, 2…Second electronic component, 3…Adhesive film, 4…First substrate, 5…Insulating layer, 6…First electrode, 7…Second substrate, 8…Second electrode, 10…First conductive particle, 11…Second conductive particle.

Claims

1. A method for manufacturing a connection body, comprising a step of electrically connecting a first electronic component having a first electrode to a second electronic component having a second electrode via an adhesive film, the first electronic component has an uneven surface, the first electrode is provided in a recess in the uneven surface, the second electrode is an electrode having a substantially flat surface with an area larger than an area of the first electrode, The adhesive film First conductive particles which are dendritic conductive particles; second conductive particles, which are conductive particles other than the first conductive particles and have a non-conductive core and a conductive layer provided on the core; Contains the depth of the recess is 25 μm or more, and the average particle size of the second conductive particles is equal to or greater than the depth of the recess; In the step, the adhesive film is disposed between the first electronic component and the second electronic component, and the second electronic component is pressure-bonded to the first electronic component so that the substantially flat surface of the second electrode is electrically connected to the first electrode.

2. The method of claim 1 , wherein the adhesive film has a thickness of 15 μm or more.

3. The manufacturing method according to claim 1 or 2, wherein the thickness of the adhesive film is equal to or greater than the depth of the recess.

4. 4. The method according to claim 1, wherein the second conductive particles have an average particle size of 2.5 times or less the depth of the recess.

5. The manufacturing method according to any one of claims 1 to 4, wherein the thickness of the adhesive film is 1.2 to 2 times the average particle size of the second conductive particles.

6. First conductive particles which are dendritic conductive particles; an adhesive film containing second conductive particles, which are conductive particles other than the first conductive particles and have a non-conductive core and a conductive layer provided on the core, It is used for electrically connecting a first electronic component having a first electrode and a second electronic component having a second electrode, the first electronic component has an uneven surface, the first electrode is provided in a recess in the uneven surface, the depth of the recess is 25 μm or more, and the average particle size of the second conductive particles is equal to or greater than the depth of the recess; the second electrode is an electrode having a substantially flat surface with an area larger than an area of the first electrode, In the electrical connection, the substantially flat surface of the second electrode is electrically connected to the first electrode.

7. 7. The adhesive film of claim 6, wherein the adhesive film has a thickness of 15 μm or more.

8. 8. The adhesive film according to claim 6, wherein the thickness of the adhesive film is equal to or greater than the depth of the recess.

9. 9. The adhesive film according to claim 6, wherein the average particle size of the second conductive particles is 2.5 times or less the depth of the recesses.

10. The adhesive film according to any one of claims 6 to 9, wherein the thickness of the adhesive film is 1.2 to 2.0 times the average particle size of the second conductive particles.

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