Adhesion method

Abstract

To provide an adhesion method for adhering a substrate and components using a conductive adhesive, capable of performing adhesion in a short time, causing less substrate damage in adhesion, and capable of performing adhesion with a high absolute value of adhesive strength and high adhesive strength per unit area.SOLUTION: An adhesion method includes adhering components to a substrate by induction heating by using a conductive adhesive containing (A) an epoxy resin, (B) a microcapsule type potential hardening agent and (C) a conductive powder. The adhesion method is such that: an induction heating time T is 1 second or more and 300 seconds or less; and the induction heating time T (second), an induction heating frequency P (kHz), and a working distance WD (mm) in induction heating satisfy the following conditions: 30≤T×P / WD≤50, or the induction heating time T (second), an induction heating power Q (kW), and the working distance WD (mm) in induction heating satisfy the following conditions: 1.1≤T×Q / WD≤2.0.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a bonding method, and more particularly to a bonding method for bonding a substrate and a component, particularly a substrate and an electronic component (conductive connection), which can achieve bonding in a short time with minimal damage to the substrate and with high absolute value of bonding strength and high bonding strength per unit area. [Background technology]

[0002] In the manufacture of circuits for electrical and electronic devices, solder has traditionally been the primary method used to bond (conductively connect) substrates and components. However, in recent years, the use of conductive adhesives to achieve conductive connections (bonding) between electrical and electronic components has been explored. For example, in electronic devices such as computers and mobile phones, conductive adhesives are being used to achieve high-density mounting and integration of various electronic components, such as LED elements, semiconductor elements, and capacitors, on the same circuit board. Patent Documents 1 to 3 describe bonding a substrate and a component using a conductive adhesive containing a conductive powder and a resin component. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-162646 [Patent Document 2] International Publication No. 2014 / 104053 [Patent Document 3] Japanese Patent Application Publication No. 10-247419 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been an increasing demand for bonding methods that can bond substrates and components with short heating times without causing thermal damage when fabricating circuits for electrical and electronic devices. As such a bonding method, bonding methods using induction heating (IH) have been investigated, as they can be used for substrates with low heat resistance or high heat dissipation. However, until now, induction heating (IH) has mainly been considered and used as a means for soldering, and the conditions for applying it to conductive adhesives and configuring bonding methods have not been studied.

[0005] The problem to be solved by the present invention is to provide a bonding method for bonding a substrate and a component using a conductive adhesive, which can perform bonding in a short time, causes little damage to the substrate during bonding, and can achieve bonding with a high absolute value of adhesive strength and adhesive strength per unit area. [Means for solving the problem]

[0006] As a result of extensive research into solving the above problems, the present inventors have found that the above problems can be solved by a specific bonding method, and have thus completed the present invention. Specifically, the method is as follows. [Section 1] A bonding method for bonding a component to a substrate by induction heating using a conductive adhesive containing (A) an epoxy resin, (B) a microcapsule-type latent curing agent, and (C) a conductive powder, comprising: The induction heating time T is 1 second or more and 300 seconds or less, The induction heating time T (seconds), induction heating frequency P (kHz) and working distance WD (mm) in induction heating are as follows: 30≦T×P / WD≦50 The bonding method satisfies the above. [Section 2] A bonding method for bonding a component to a substrate by induction heating using a conductive adhesive containing (A) an epoxy resin, (B) a microcapsule-type latent curing agent, and (C) a conductive powder, comprising: The induction heating time T is 1 second or more and 300 seconds or less, The induction heating time T (seconds), induction heating power Q (kW) and working distance WD (mm) are as follows: 1.1≦T×Q / WD≦2.0 The bonding method satisfies the above. [Section 3] A bonding method for bonding a component to a glass substrate by induction heating using a conductive adhesive containing (A) an epoxy resin, (B) a microcapsule-type latent curing agent, and (C) a conductive powder, comprising: The induction heating time T is 1 second or more and 300 seconds or less, The induction heating time T (seconds), induction heating power Q (kW) and working distance WD (mm) are as follows: 1.1≦T×Q / WD≦14.0 The bonding method satisfies the above. [Section 4] A bonding method for bonding a component to a substrate by induction heating using a conductive adhesive containing (A) an epoxy resin, (B) a microcapsule-type latent curing agent, and (C) a conductive powder, comprising: The above bonding method, wherein the induction heating time T is 1 second or more and 300 seconds or less, and the absolute value (gf) of the adhesive strength between the bonded substrate and component is 3,000 gf or more. [Section 5] A bonding method for bonding a component to a substrate by induction heating using a conductive adhesive containing (A) an epoxy resin, (B) a microcapsule-type latent curing agent, and (C) a conductive powder, comprising: The above bonding method, wherein the induction heating time T is 1 second or more and 300 seconds or less, and the bond strength (MPa) per unit area of ​​the bonded substrate and component is 5.7 MPa or more. [Section 6] Item 6. The bonding method according to any one of Items 1, 2, 4, and 5, wherein the substrate comprises one or more selected from the group consisting of ceramics, glass, polyimide resin, polyphenylene sulfide resin, polysulfone resin, polyether ether ketone resin, polyether sulfone resin, polyphenylene ether resin, polyacetal resin, polyoxymethylene resin, cycloolefin polymer, polybutylene terephthalate resin, polyamide-imide resin, polyetherimide resin, polyethernitrile resin, polyarylate resin, liquid crystal polymer, polyethylene terephthalate resin, polyethylene naphthalate resin, acrylic resin, polycarbonate resin, polyvinyl chloride resin, fluororesin, acrylonitrile-butadiene-styrene resin, acrylonitrile-styrene resin, polyamide resin, polystyrene resin, phenolic resin, epoxy resin, urethane resin, maleimide resin, cyanate resin, urea resin, melamine resin, polyolefin resin, thermoplastic elastomer, paper, textile, composites of one or more of these, and mixtures of one or more of these. [Section 7] Item 7. The bonding method according to any one of items 1 to 6, wherein the conductive adhesive further contains (D) a thiol compound. [Effects of the Invention]

[0007] The present invention provides a bonding method for bonding a substrate and a component using a conductive adhesive, which can perform bonding in a short time, causes little damage to the substrate during bonding, and achieves bonding with a high absolute value of adhesive strength and adhesive strength per unit area. DETAILED DESCRIPTION OF THE INVENTION

[0008] A bonding method according to a first aspect of the present invention is a bonding method for bonding a component to a substrate by induction heating using a conductive adhesive containing (A) an epoxy resin, (B) a microcapsule-type latent curing agent, and (C) a conductive powder, wherein the induction heating time T is 1 second or more and 300 seconds or less, and the induction heating time T (seconds), the induction heating frequency P (kHz), and the working distance WD (mm) during induction heating satisfy the following conditions: 30≦T×P / WD≦50 The above-mentioned bonding method satisfies the above-mentioned condition.

[0009] A bonding method according to a second aspect of the present invention is a bonding method for bonding a component to a substrate by induction heating using a conductive adhesive containing (A) an epoxy resin, (B) a microcapsule-type latent curing agent, and (C) a conductive powder, the method comprising: The induction heating time T is 1 second or more and 300 seconds or less, The induction heating time T (seconds), induction heating power Q (kW) and working distance WD (mm) are as follows: 1.1≦T×Q / WD≦2.0 The above-mentioned bonding method satisfies the above-mentioned condition.

[0010] A bonding method according to a third aspect of the present invention is a bonding method for bonding a component to a glass substrate by induction heating using a conductive adhesive containing (A) an epoxy resin, (B) a microcapsule-type latent curing agent, and (C) a conductive powder, the method comprising: The induction heating time T is 1 second or more and 300 seconds or less, The induction heating time T (seconds), induction heating power Q (kW) and working distance WD (mm) are as follows: 1.1≦T×Q / WD≦14.0 The above-mentioned bonding method satisfies the above-mentioned condition.

[0011] A bonding method according to a fourth aspect of the present invention is a bonding method for bonding a component to a substrate by induction heating using a conductive adhesive containing (A) an epoxy resin, (B) a microcapsule-type latent curing agent, and (C) a conductive powder, wherein the induction heating time T is 1 second or more and 300 seconds or less, and the absolute value of the adhesive strength (gf) between the bonded substrate and component is 3,000 gf or more.

[0012] A bonding method according to a fifth aspect of the present invention is a bonding method for bonding a component to a substrate by induction heating using a conductive adhesive containing (A) an epoxy resin, (B) a microcapsule-type latent curing agent, and (C) a conductive powder, wherein the induction heating time T is 1 second or more and 300 seconds or less, and the adhesive strength (MPa) per unit area of ​​the bonded substrate and component is 5.7 MPa or more.

[0013] In the bonding methods according to the first, second, fourth and fifth aspects of the present invention, the substrate is made of ceramics, glass, polyimide resin, polyphenylene sulfide resin, polysulfone resin, polyether ether ketone resin, polyether sulfone resin, polyphenylene ether resin, polyacetal resin, polyoxymethylene resin, cycloolefin polymer, polybutylene terephthalate resin, polyamideimide resin, polyetherimide resin, polyethernitrile resin, polyarylate resin, liquid crystal polymer, polyethylene terephthalate The resin composition may contain one or more selected from the group consisting of a polyethylene naphthalate resin, an acrylic resin, a polycarbonate resin, a polyvinyl chloride resin, a fluororesin, an acrylonitrile-butadiene-styrene resin, an acrylonitrile-styrene resin, a polyamide resin, a polystyrene resin, a phenol resin, an epoxy resin, a urethane resin, a maleimide resin, a cyanate resin, a urea resin, a melamine resin, a polyolefin resin, a thermoplastic elastomer, paper, a textile, a composite of one or more of these, and a mixture of one or more of these.

[0014] In the bonding methods according to the first to fifth aspects of the present invention, the conductive adhesive may further contain (D) a thiol compound. Each bonding method will be described in detail below.

[0015] [Bonding method according to the first embodiment] <<Conductive adhesive>> The conductive adhesive used in the bonding method according to the first aspect of the present invention is a conductive adhesive containing (A) an epoxy resin, (B) a microcapsule-type latent curing agent, and (C) a conductive powder.

[0016] <(A) Epoxy resin> The conductive adhesive used in the bonding method according to the first aspect of the present invention contains (A) an epoxy resin. The epoxy resin is not particularly limited as long as it has one or more epoxy groups in its molecule.

[0017] The epoxy resin may be any of an aromatic epoxy resin, an alicyclic epoxy resin, and an aliphatic epoxy resin. The epoxy resin may be any of a monomer, an oligomer, and a polymer having two or more glycidyl groups (epoxy groups) in one molecule, and the molecular weight is not particularly limited.

[0018] Examples of epoxy resins include bisphenol-type epoxy resins, biphenyl-type epoxy resins, alkylene oxide-modified bisphenol-type epoxy resins, phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, naphthalene-type epoxy resins, aromatic glycidylamine-type epoxy resins, resorcinol diglycidyl ether, hydroquinone-type epoxy resins, stilbene-type epoxy resins, triphenolmethane-type epoxy resins, triphenolpropane-type epoxy resins, alkyl-modified triphenolmethane-type epoxy resins, triazine ring-containing epoxy resins, naphthol-type epoxy resins, aromatic aralkyl-type epoxy resins, chelate-modified aromatic epoxy resins, dicyclopentadiene-type epoxy resins, condensed alicyclic epoxy resins, hydrogenated aromatic epoxy resins, glycidyl ethers of alicyclic polyols, glycidyl ethers of aliphatic polyols, and triazine nucleus-containing epoxy resins. The epoxy resins may be used alone or in combination of two or more.

[0019] In the present invention, the epoxy resin preferably contains one or more of a bisphenol-type epoxy resin, a biphenyl-type epoxy resin, a fluorene-type epoxy resin, a phenol novolac-type epoxy resin, a dicyclopentadiene-type epoxy resin, and a naphthalene-type epoxy resin, and more preferably contains a bisphenol-type epoxy resin and a dicyclopentadiene-type epoxy resin.

[0020] (bisphenol-type epoxy resin) Bisphenol-type epoxy resins have the formula (a1) in the molecule; [ka] There are no particular limitations on the epoxy resin as long as it has one or more bisphenol-type skeletons represented by the following formula and one or more epoxy groups. In formula (a1), b11 is an integer from 0 to 4, and b12 is an integer from 0 to 4. R c is a substituent, and R cWhen there are multiple R, they may be the same or different. c Examples of the substituent include a halogen atom, a hydrocarbon group, an alkoxy group, a cycloalkyloxy group, an aryloxy group, an aralkyloxy group, an alkylthio group, a cycloalkylthio group, an arylthio group, an aralkylthio group, an acyl group, a nitro group, a cyano group, etc. The substituent may be one type alone or two or more types. X is [ka] A group selected from R a11 and R a12 represents hydrogen or an optionally substituted hydrocarbon group having 1 to 20 carbon atoms, and may be the same or different and may be bonded to each other to form a ring. In the present invention, X in formula (a1) is [ka] It is preferable that the group is a group selected from the following:

[0021] The bisphenol-type epoxy resin preferably has two or more epoxy groups. The epoxy equivalent of the bisphenol-type epoxy resin is not particularly limited. For example, it can be 100 g / eq or more, preferably 150 g / eq or more, and for example, it can be 5,000 g / eq or less, preferably 2,000 g / eq or less. Epoxy equivalent weight is the number of grams of epoxy resin containing one equivalent of epoxy groups (g / eq).

[0022] Examples of bisphenol type epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AD ​​type epoxy resins, bisphenol S type epoxy resins, bisphenol AF type epoxy resins, bisphenol B type epoxy resins, bisphenol BP type epoxy resins, bisphenol AP type epoxy resins, bisphenol E type epoxy resins, bisphenol Z type epoxy resins, etc. Among these, bisphenol A type epoxy resins, bisphenol F type epoxy resins, and bisphenol AD ​​type epoxy resins are preferred, and bisphenol A type epoxy resins are more preferred. The bisphenol type epoxy resin may be used alone or in combination of two or more.

[0023] (Dicyclopentadiene epoxy resin) Dicyclopentadiene type epoxy resins have the formula (a2) in the molecule; [ka] There are no particular limitations on the epoxy resin as long as it has one or more dicyclopentadiene skeletons represented by the following formula and one or more epoxy groups. The dicyclopentadiene epoxy resin preferably has two or more epoxy groups. Examples of dicyclopentadiene epoxy resins include those obtained by epoxidizing dicyclopentadiene polyols and dicyclopentadiene phenol epoxy resins. Commercially available products include the ADEKA RESIN series (EP-4088S, EP-4088L, etc.) manufactured by ADEKA Corporation, the EPICLON series (HP-7200, HP-7200L, HP-7200H, HP-7200HHH, HP-7200H-75M, etc.) manufactured by DIC Corporation, TACTIX-556 manufactured by Huntsman Advanced Materials, and the XD series (1000, 1000-2L, 1000-H, etc.) manufactured by Nippon Kayaku Co., Ltd.

[0024] The content of epoxy resin in the conductive adhesive is not particularly limited. It can be, for example, 0.5 parts by mass or more, preferably 1.0 parts by mass or more, relative to a total of 100 parts by mass of the epoxy resin, microcapsule-type latent curing agent, conductive powder, and optionally contained thiol compound. It can be, for example, 15.0 parts by mass or less, preferably 13.0 parts by mass or less. If the content of epoxy resin is less than 0.5 parts by mass relative to a total of 100 parts by mass of the epoxy resin, microcapsule-type latent curing agent, conductive powder, and thiol compound, there is a risk of one or more of the following: (a) the conductive adhesive does not form a film; (b) the absolute value of the adhesive strength and the adhesive strength per unit area decrease; and (c) heat resistance decreases. If the content exceeds 15.0 parts by mass, there is a risk of (a) the curing time taking longer and / or (b) the conductivity decreasing.

[0025] <(B) Microcapsule-type latent curing agent> The conductive adhesive used in the bonding method according to the first aspect of the present invention contains (B) a microencapsulated latent curing agent. The microencapsulated latent curing agent is not particularly limited as long as it is a curing agent encapsulated in an encapsulating material.

[0026] Examples of the curing agent include imidazole compounds, polyhydric phenol compounds, acid anhydrides, amine compounds, hydrazide compounds, mercapto compounds, Lewis acid-amine complexes, latent curing agents, etc. One type of curing agent may be used alone, or two or more types may be used.

[0027] Examples of the capsule material include vinyl compounds, urea compounds, phenolic resins, urethane resins, epoxy resins, polyethylene, polypropylene, polystyrene, nylon, polyester, polyvinyl chloride, polyvinylidene chloride, thermoplastic resins, and mixtures thereof. The encapsulant can be destroyed by any means, such as by impact, heat, light, etc., and is preferably destroyed by heat.

[0028] As the (B) microcapsule-type latent curing agent, a microcapsule-type latent curing agent obtained by treating an amine adduct-type latent curing agent with an isocyanate is preferred. The microcapsule-type latent curing agent may be used alone or in combination of two or more.

[0029] The average particle size of the microcapsule-type latent curing agent is not particularly limited. From the viewpoint of dispersibility in the conductive adhesive, it is, for example, 20 μm or less, preferably 12 μm or less. The average particle size refers to the average particle size defined by the median diameter. More specifically, it refers to the Stokes diameter measured by a laser diffraction / light scattering method using a particle size distribution analyzer.

[0030] Examples of microcapsule-type latent curing agents include the Novacure series manufactured by Asahi Kasei Corporation (e.g., HX-3941HP, HXA-3792, HXA-3922HP, HXA-3932HP, HXA-3042HP, HX-3721, HX-3722, HX-3088, HX-3921HP, HX-3741, HX-3742, HX-3748, HX-3613, HX-3088, HX-3921HP, etc.); and LC-80 manufactured by A&C Catalysts.

[0031] The content of the microcapsule-type latent curing agent in the conductive adhesive is not particularly limited. It can be, for example, 0.1 parts by mass or more, preferably 0.5 parts by mass or more, and more preferably 1.0 parts by mass or more, relative to 100 parts by mass of the epoxy resin in the conductive adhesive. It can be, for example, 50.0 parts by mass or less, preferably 40.0 parts by mass or less, and more preferably 30.0 parts by mass or less. If the content of the microcapsule-type latent curing agent relative to 100 parts by mass of the epoxy resin in the conductive adhesive is less than 0.1 parts by mass, the curing properties of the conductive adhesive may be reduced, and it may take a long time to cure. If the content exceeds 50.0 parts by mass, the conductive adhesive may not solidify and may not form a film.

[0032] <(C) Conductive powder> The conductive adhesive used in the bonding method according to the first aspect of the present invention contains (C) conductive powder. Examples of conductive powders include silver-coated copper powder, silver-based powder, nickel-based powder, conductive carbon powder (carbon black, activated carbon, carbon fiber, carbon nanotubes, graphene, etc.), copper-based powder, gold-based powder, lead-free solder powder, tin-based powder, zinc-based powder, aluminum-based powder, iron-based powder, metal alloy powder, and metal-coated resin particles. The conductive powder may be used alone or in combination of two or more kinds.

[0033] The shape of the conductive powder is not particularly limited. It may be spherical, approximately spherical (for example, with a length-to-width aspect ratio of 1.5 or less), dendritic, flat, block-like, plate-like, polygonal pyramidal, polyhedral, flake-like (scale-like), rod-like, fibrous, needle-like, or irregularly shaped. From the viewpoints of oxidation resistance, volume resistivity, dispersibility, handleability, and the like, spherical, approximately spherical, flat, or flake-like (scale-like) shapes are preferred.

[0034] In the present invention, from the viewpoints of cost, conductivity, migration properties, etc., it is preferable to use one or more conductive powders selected from silver-coated copper powder, silver-based powder, nickel-based powder, and conductive carbon powder, and it is more preferable to use silver-coated copper powder.

[0035] (Silver-coated copper powder) The silver-coated copper powder is not particularly limited as long as it is copper powder whose surface is coated with silver. By coating the copper powder with silver, it is possible to improve oxidation resistance, reduce volume resistivity, and improve the storage stability of the conductive adhesive. The method for producing the silver-coated copper powder is not particularly limited. For example, any silver-coated copper powder may be used, such as silver-plated copper powder or silver-coated copper powder produced by a substitution reaction between copper and silver.

[0036] The volume average particle size of the silver-coated copper powder is not particularly limited. For example, it can be 0.1 μm or more, preferably 0.5 μm or more, and can be 100 μm or less, preferably 20 μm or less. For example, to enable printing of the conductive adhesive, particularly application by screen printing or dispenser method, the volume average particle size is preferably 0.5 μm or more and 10 μm or less. The average particle size of the silver-coated copper powder is the value of the volume cumulative particle size D50 at 50% by volume of cumulative volume measured by a laser diffraction scattering particle size distribution measurement method. If the average particle diameter of the silver-coated copper powder is larger than 10 μm, there is a risk of reduced leveling, breaks in the wiring pattern, and difficulty in forming a narrow wiring pattern. If it is smaller than 0.5 μm, there is a risk of the copper being exposed and oxidized, resulting in an increase in resistivity over time.

[0037] The thickness of the flaky silver-coated copper powder is not particularly limited, and can be, for example, 0.01 μm or more, preferably 0.05 μm or more, and can be, for example, 20.0 μm or less, preferably 10.0 μm or less.

[0038] Specific examples of silver-coated copper powders include 10%Ag-coated Cu-HWQ5μm, 10%Ag-coated FCC-2000, 10%Ag-coated FCC-115, 10%Ag-coated 2L3 (all manufactured by Fukuda Metal Foil & Powder Co., Ltd.), 10%Ag / 1100Y, 10%Ag / 1100YP, 10%Ag / 05KP, ACFY-2, ACAX-225, ACBY-2 (all manufactured by Mitsui Mining & Smelting Co., Ltd.), TFM-C02P, TFM-C05P, TFM-C05F, TFM-C15F (all manufactured by Toyo Aluminum KK), and the like. The silver-coated copper powder may be used alone or in combination of two or more kinds.

[0039] The silver content of the silver-coated copper powder is preferably 5% by mass or more and 30% by mass or less. If the silver content is less than 5% by mass, the copper core may be exposed, and the resistivity of the wiring pattern may increase over time. If the silver content is more than 30% by mass, the possibility of ion migration may increase.

[0040] The content of the conductive powder in the conductive adhesive is not particularly limited. It can be, for example, 75% by mass or more, preferably 80% by mass or more, and more preferably 82% by mass or more, and can be, for example, 97% by mass or less, preferably 95% by mass or less, and more preferably 93% by mass or less, based on 100% by mass of the total amount of the cured conductive adhesive. If the content of the conductive powder is less than 75% by mass based on 100% by mass of the total amount of the cured conductive adhesive, the resulting cured conductive adhesive (conductive film) may have insufficient conductivity (high volume resistivity). If it exceeds 97% by mass, the absolute value of the adhesive strength and the adhesive strength per unit area when bonded by the conductive adhesive may be insufficient.

[0041] <(D) Thiol Compound> The conductive adhesive used in the bonding method according to the first aspect of the present invention may contain (D) a thiol compound in addition to (A) an epoxy resin, (B) a microcapsule-type latent curing agent, and (C) a conductive powder. Examples of (D) thiol compounds include thiol compounds having one or more, preferably two or more, thiol groups in the molecular structure that can react with epoxy groups. As the thiol compound, a polyfunctional thiol compound having 2 to 6 thiol groups (difunctional to hexafunctional) in the molecular structure is preferred. The thiol equivalent is not particularly limited. For low-molecular-weight thiol compounds with a molecular weight of less than 500, it can be, for example, 50 g / eq or more and 200 g / eq or less, and for high-molecular-weight thiol compounds with a weight-average molecular weight of 500 or more, it can be, for example, 250 g / eq or more and 5,000 g / eq or less. Thiol equivalent weight is the number of grams (g / eq) of a thiol compound that contains one equivalent of a thiol group.

[0042] Examples of thiol compounds include trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptopropionate), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, tris(3-mercaptopropyl)isocyanurate, ethylene glycol bisthioglycolate, trimethylolpropane tristhioglycolate, pentaerythritol tetrakisthioglycolate, pentaerythritol tetrakis(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, Examples of suitable thiol compounds include thiol compounds (polyfunctional thiol compounds) such as 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropane tris(3-mercaptobutyrate), trimethylolethane tris(3-mercaptobutyrate), 1,3,4,6-tetrakis(2-mercaptoethyl)glycoluril, 1,3,4,6-tetrakis(2-mercaptopropyl)glycoluril, 4,4'-isopropylidenebis[(3-mercaptopropoxy)benzene] and 1,3,5-triazine-2,4,6-trithiol, and polysulfide polymers having a thiol group. The thiol compounds may be used alone or in combination of two or more.

[0043] The content of the thiol compound in the conductive adhesive is not particularly limited. For one equivalent of epoxy groups in the epoxy resin in the conductive adhesive, the amount of thiol groups can be, for example, 1.5 equivalents or less, preferably 1.1 equivalents or less. If the amount exceeds 1.5 equivalents, the excess unreacted curing agent may cause poor curing of the cured film, resulting in a decrease in film hardness and a decrease in the reliability of the conductive connection.

[0044] The content of the thiol compound in the conductive adhesive can be, for example, 250 parts by mass or less, preferably 200 parts by mass or less, per 100 parts by mass of the epoxy resin in the conductive adhesive. If the content of the thiol compound exceeds 250 parts by mass per 100 parts by mass of the epoxy resin in the conductive adhesive, the conductive adhesive may not solidify and may not form a film.

[0045] <(E) Epoxy resin curing agent other than (B) and other than (D)> The conductive adhesive used in the bonding method according to the first aspect of the present invention may contain, in addition to (A) the epoxy resin, (B) the microcapsule-type latent curing agent, and (C) the conductive powder, an epoxy resin curing agent other than the (B) microcapsule-type latent curing agent and other than the (D) thiol compound as component (E). Furthermore, the conductive adhesive used in the bonding method according to the first aspect of the present invention may contain, in addition to the (A) epoxy resin, (B) microcapsule-type latent curing agent, (C) conductive powder, and (D) thiol compound, an epoxy resin curing agent other than the (B) microcapsule-type latent curing agent and the (D) thiol compound as component (E).

[0046] (E) The epoxy resin curing agent other than the (B) microcapsule-type latent curing agent and the (D) thiol compound is not particularly limited as long as it acts as an epoxy resin curing agent. Examples include amine-based curing agents, imidazole-based curing agents, phenol-based curing agents, acid anhydride-based curing agents, hydrazide-based curing agents, Lewis acid-amine complex-based curing agents, and latent curing agents. The epoxy resin curing agent other than the (B) microcapsule-type latent curing agent and the (D) thiol compound, which is the component (E), may be used alone or in combination of two or more.

[0047] <(F) Coupling agent> The conductive adhesive used in the bonding method according to the first aspect of the present invention may contain a coupling agent as component (F) in addition to (A) the epoxy resin, (B) the microcapsule-type latent curing agent, and (C) the conductive powder. Furthermore, the conductive adhesive used in the bonding method according to the first aspect of the present invention may contain, in addition to (A) the epoxy resin, (B) the microcapsule-type latent curing agent, (C) the conductive powder, and (F) the coupling agent, a thiol compound as component (D), and / or an epoxy resin curing agent other than the (B) microcapsule-type latent curing agent and the (D) thiol compound as component (E).

[0048] Examples of the (F) coupling agent include a silane coupling agent, a titanium coupling agent, a borane coupling agent, an aluminum coupling agent, a zirconium coupling agent, etc. One type of (F) coupling agent may be used alone, or two or more types may be used. In the conductive adhesive used in the bonding method according to the first aspect of the present invention, preferred silane coupling agents include aminoalkyltrialkoxysilane, vinyltrialkoxysilane, (meth)acryloyloxyalkyltrialkoxysilane, glycidoxyalkyltrialkoxysilane, glycidoxyalkylalkyldialkoxysilane, mercaptoalkyltrialkoxysilane, tetraalkoxysilane, alkyltrialkoxysilane, dialkyldialkoxysilane, etc. One type of silane coupling agent may be used alone, or two or more types may be used.

[0049] <Other ingredients> The conductive adhesive used in the bonding method according to the first aspect of the present invention may contain, as necessary, "other components" such as wetting and dispersing agents, fillers, solvents, resins other than epoxy resins, adhesion promoters, viscoelasticity modifiers, curing accelerators (curing catalysts), reactive diluents, antioxidants, gap adjusters (spacers; spacing control agents), organic acid compounds, pigments, corrosion inhibitors, surfactants, antifoaming agents, dispersants, viscosity modifiers (thixotropy modifiers), adhesion promoters, anti-settling agents, pH adjusters, leveling agents, UV absorbers, flame retardants, and heavy metal deactivators, provided that their performance is not impaired. The other components may be used alone or in combination of two or more.

[0050] <Conductivity of cured conductive adhesive film> The conductive adhesive used in the bonding method according to the first aspect of the present invention has a low volume resistivity of the cured film and excellent conductivity. The volume resistivity of the cured film of the conductive adhesive is, for example, 1.0 × 10 -2 Ω cm, preferably less than 8.0 × 10 -3 Ω·cm, more preferably less than 5.0×10 -3 The volume resistivity of the cured film can be determined, for example, by casting or applying the conductive adhesive onto a substrate, curing it by heating using a heating method such as induction heating or oven heating to form a cured film with a thickness of 80 to 100 μm, and measuring the volume resistivity with a resistivity meter (for example, the Loresta GP-MCP T610 (manufactured by Nitto Seiko Analytech Co., Ltd.)). The conductive adhesive used in the bonding method of the present invention can also be used as a substantially isotropically and anisotropically conductive material.

[0051] <Method for preparing conductive adhesive> The method for preparing the conductive adhesive used in the bonding method according to the first aspect of the present invention is not particularly limited. For example, the conductive adhesive may be prepared by adding an epoxy resin, a microcapsule-type latent curing agent, a conductive powder, and other components used as needed to a mixing vessel in any order and mixing and stirring them. The mixing and stirring can be performed using, for example, a ball mill, a roll mill, a bead mill, a planetary mixer, a tumbler, a stirrer, a mixer, a mechanical homogenizer, an ultrasonic homogenizer, a high-pressure homogenizer, a paint shaker, a V-type blender, a Nauta mixer, a Banbury mixer, a planetary mixer, a kneading roll, a single-screw or twin-screw extruder, or the like.

[0052] The temperature at which the conductive adhesive is prepared (the temperature at which the components are mixed) is not particularly limited. Heating can be performed as necessary, and the temperature can be, for example, 10 to 40°C. The atmosphere in which the conductive adhesive is prepared is not particularly limited, and the preparation can be carried out in air or in an inert atmosphere.

[0053] <Conductive adhesive shape, etc.> The form of the conductive adhesive used in the bonding method according to the first aspect of the present invention is not particularly limited, but it is preferably in a liquid form (paste or varnish), film form, or powder form at room temperature (25°C ± 5°C). The liquid conductive adhesive can be obtained by, for example, stirring and mixing the components of the conductive adhesive, and can also be mixed with a solvent such as an organic solvent as needed. A film-like conductive adhesive can be obtained, for example, by stirring and mixing the components of the conductive adhesive, and if necessary, adding a solvent such as an organic solvent to obtain a liquid conductive adhesive, which is then cast and coated onto a releasable substrate to form a film, dried to remove the solvent, and then peeled off from the releasable substrate. Furthermore, a film-like conductive adhesive can be obtained by impregnating a nonwoven fabric or the like with the conductive adhesive, forming the conductive adhesive on a releasable substrate, drying the conductive adhesive to remove the solvent, and then peeling the conductive adhesive off the releasable substrate.

[0054] <<Base material>> The substrate used in the bonding method according to the first aspect of the present invention is not particularly limited as long as it is an insulating material. Examples of materials constituting the substrate include ceramics, glass, polyimide resin, polyphenylene sulfide resin, polysulfone resin, polyether ether ketone resin, polyether sulfone resin, polyphenylene ether resin, polyacetal resin, polyoxymethylene resin, cycloolefin polymer, polybutylene terephthalate resin, polyamideimide resin, polyetherimide resin, polyethernitrile resin, polyarylate resin, liquid crystal polymer, polyethylene terephthalate resin, polyethylene naphthalate resin, acrylic resin, polycarbonate resin, polyvinyl chloride resin, fluororesin, acrylonitrile-butadiene-styrene resin, acrylonitrile-styrene resin, polyamide resin, polystyrene resin, phenolic resin, epoxy resin, urethane resin, maleimide resin, cyanate resin, urea resin, melamine resin, polyolefin resin, thermoplastic elastomer, paper, textile, composites of one or more of these, and mixtures of one or more of these. The form of the substrate is not particularly limited, and may be, for example, a film, a sheet, a resin molded product such as a housing, or the like.

[0055] The substrate may have a conductor provided on a portion thereof. The conductor may be a conductive layer partially laminated on the substrate by pasting, printing, etching, or the like. The conductive layer may be an electrode in a circuit, etc. The conductive layer is usually made of a metal, and examples of the metal constituting the conductive layer include one or more selected from the group consisting of copper, silver, aluminum, gold, nickel, tin, solder, bismuth, zinc, iron, cobalt, titanium, silicon, carbon, alloys containing two or more of these, and oxides thereof. The substrate and conductive layer may be, for example, a circuit board with a printed circuit formed on its surface, or an interposer with electrode pads formed on both sides, in which the substrate and conductive layer are integrated.

[0056] The conductive layer provided on the substrate usually has an area that can be heated by induction heating. For example, it preferably has an area of ​​0.2 mm × 0.2 mm or more. If the area of ​​the conductive layer is limited, a conductive pad for auxiliary heating can be provided on the surface of the substrate where the conductive layer is not provided or adjacent to the conductive layer. In the present invention, it is preferable to use a substrate provided with a conductive layer.

[0057] <<Parts>> The components used in the bonding method of the present invention are not particularly limited as long as they can be bonded to a substrate with a conductive adhesive. The components are preferably, for example, electric or electronic components having conductive portions such as electrodes or terminals. Examples of the components include one or more components selected from the group consisting of semiconductor elements, resistors, capacitors, LED elements, sensor elements, LSIs, ICs, inductors, transistors, liquid crystal display elements, piezoelectric elements, registers, filters, quartz oscillators, connectors, switches, motors, actuators, batteries, solar cells, microphones, camera modules, communication modules, heaters, heat sinks, vapor chambers, optical modules, etc.

[0058] <<Induction heating>> <Induction heating means> Induction heating utilizes the phenomenon in which Joule heat is generated when an eddy current is passed through a conductive material. The first bonding method of the present invention involves causing the conductive material (the conductive layer on the substrate, the conductive layer of the component, the conductive powder or magnetic powder in the conductive adhesive, etc.) to self-heat, thereby thermally curing the conductive adhesive at any location in a short period of time.

[0059] The induction heating means is not particularly limited. For example, an induction heating (IH) device may be used, which includes at least a coil having a space inside it in a plan view, a magnetic body that can move vertically relative to the space, an adjustment mechanism for adjusting the distance (working distance WD) between the coil and the conductor within the space, and a power source that applies an AC voltage to the coil to pass a high-frequency current. By placing a magnetic body in the space inside the coil, the magnetic flux φ generated in the space inside the coil can be irradiated so as to be focused on the conductor (e.g., a conductive layer provided on a substrate) without being attenuated by the magnetic body. This allows the magnetic flux φ to be efficiently used for induction heating of the conductor, which allows the conductive adhesive to thermally harden and efficiently bond the conductor. Examples of magnetic bodies include ferrite.

[0060] The position of the magnetic body placed in the space inside this coil can be adjusted, and the heating efficiency can be adjusted by changing the distance from the conductor to be irradiated. The closer the distance, the more efficiently the magnetic flux φ converged by the magnetic body can be irradiated onto the conductor, thereby increasing heating efficiency. In addition, by setting this distance to zero (pressing the magnetic body directly against the component), it is possible to prevent the conductor from moving due to the influence of the magnetic field generated during induction heating. The temperature of the magnetic material during induction heating is preferably 40° C. or less. If the temperature exceeds 40° C., the magnetic permeability of the magnetic material decreases, resulting in a decrease in heating efficiency.

[0061] When a substrate is used in which a conductive pad for auxiliary heating is provided on a surface of the substrate that does not have a conductive layer or adjacent to a conductive layer, and the volume of the conductive pad for auxiliary heating is made larger relative to the volume of the conductive layer or conductive adhesive, the amount of heat generated by induction heating can be increased, and the heat generated by the conductive pad for auxiliary heating can be transferred to the conductive adhesive, thereby enabling the conductive adhesive to be effectively thermally cured. In this case, since it is possible to suppress the temperature rise of the substrate, it is possible to thermally cure the conductive adhesive even when bonding substrates that do not have high heat resistance. Furthermore, when the volume resistivity of the auxiliary heating conductive pad is reduced, the heat generation amount of the dielectric heating can be increased, and the conductive adhesive can be effectively thermally cured.

[0062] <Bonding method using induction heating means> The bonding method using induction heating means is not particularly limited, and examples thereof include a method in which a conductive adhesive is interposed between a substrate and a component, and the conductive adhesive is thermally cured by induction heating such as electromagnetic induction heating, thereby bonding the substrate and the component with the conductive adhesive. In this case, a substrate provided with a conductive layer is used, a component having a conductive portion is used, and a conductive adhesive is interposed between the conductive layer and the conductive portion, and induction heating is performed, thereby forming a conductive connection. It is also possible to use substrates and components that do not contain conductive material, interpose a conductive adhesive between the substrate and the component, and use induction heating to cause the conductive powder or magnetic particles in the conductive adhesive to self-heat, thereby thermosetting the conductive adhesive and bonding non-conductive materials together.

[0063] <Induction heating time T> In the bonding method according to the first aspect of the present invention, the induction heating time T is 1 second or more and 300 seconds or less. The induction heating time is the time during which a high-frequency current is passed through the coil. If the induction heating time T is less than 1 second, the induction heating may be insufficient, and the conductive adhesive may not be heated sufficiently to perform bonding or the adhesive strength may be insufficient. If it exceeds 300 seconds, the induction heating may be excessive, and thermal damage may occur to one or more of the substrate, component, and conductive adhesive. In the bonding method according to the first aspect of the present invention, the induction heating time T can be adjusted as appropriate, taking into consideration the induction heating frequency P (control of the amount of current), working distance WD (attenuating in proportion to the square of WD), conductive layer area, conductive layer thickness, conductive layer volume resistivity, conductive layer thermal conductivity, substrate thermal conductivity, substrate thickness, distance between the magnetic material and the object to be heated, magnetic material shape, coil height, coil shape, environmental thermal conductivity, wind speed, temperature, humidity, environmental atmosphere (vacuum, inert gas, reducing atmosphere, etc.), etc. The bonding method according to the first aspect of the present invention can bond a substrate and a component by thermally curing the conductive adhesive through heating in a short period of time, and therefore can be applied to substrates and components that do not have very high heat resistance.

[0064] <T×P / WD> In the bonding method according to the first aspect of the present invention, the induction heating time T (seconds), the induction heating frequency P (kHz), and the working distance WD (mm) are set to the following conditions: 30≦T×P / WD≦50 Meet the following.

[0065] The induction heating frequency P (kHz) is the frequency of the high-frequency current passed through the coil. The induction heating frequency P can be set, for example, in the range of 90 kHz to 900 kHz. To facilitate adjustment of T×P / WD, the induction heating frequency P is preferably in the range of 90 kHz to 270 kHz. By adjusting the induction heating frequency P, it is possible to control the heating during induction heating.

[0066] The working distance WD (mm) is the distance between the magnetic body, which is movable in a direction perpendicular to the space inside the coil, and the conductor in the space inside the coil. The working distance WD can be, for example, 3 mm or more, preferably 5 mm or more, and can be, for example, 30 mm or less, preferably 20 mm or less. Adjusting the working distance WD makes it possible to control the heating during induction heating.

[0067] In the bonding method according to the first aspect of the present invention, if "T×P / WD" is less than 30, induction heating cannot be performed sufficiently, resulting in insufficient thermal curing of the conductive adhesive and the risk of poor adhesion. Also, if "T×P / WD" is more than 50, induction heating becomes excessive, resulting in thermal damage to one or more of the substrate, component, and adhesive, which may result in thermal damage to the substrate and component or poor adhesion.

[0068] [Adhesion method according to the second embodiment] The conductive adhesive, substrate, and component used in the bonding method according to the second embodiment are the same as the conductive adhesive, substrate, and component used in the bonding method according to the first embodiment. The induction heating means for induction heating, the bonding method using the induction heating means, and the induction heating time in the bonding method according to the second embodiment are the same as the induction heating means for induction heating, the bonding method using the induction heating means, and the induction heating time in the bonding method according to the first embodiment.

[0069] <<Induction heating>> <T×Q / WD> In the bonding method according to the second aspect of the present invention, the induction heating time T (seconds), the induction heating power Q (kW), and the working distance WD (mm) are set to the following conditions: 1.1≦T×Q / WD≦2.0 Meet the following.

[0070] The induction heating power Q (kW) is the voltage of the high-frequency current flowing through the coil. The induction heating power Q can be set, for example, in the range of 3.5 kW to 35.0 kW. To facilitate adjustment of T×Q / WD, the induction heating frequency Q is preferably in the range of 3.5 kW to 10.5 kW. By adjusting the induction heating power Q, it is possible to control the heating during induction heating.

[0071] The working distance WD (mm) is the distance between the magnetic body, which is movable in a direction perpendicular to the space inside the coil, and the conductor in the space inside the coil. The working distance WD can be, for example, 3 mm or more, preferably 5 mm or more, and can be, for example, 30 mm or less, preferably 20 mm or less. Adjusting the working distance WD makes it possible to control the heating during induction heating.

[0072] In the bonding method according to the second aspect of the present invention, if "T×Q / WD" is less than 1.1, induction heating cannot be performed sufficiently, resulting in insufficient thermal curing of the conductive adhesive and the risk of poor adhesion. Furthermore, if "T×Q / WD" is more than 2.0, depending on the substrate, excessive induction heating may occur, resulting in thermal damage to one or more of the substrate, component, and adhesive, potentially resulting in thermal damage to the substrate and component or poor adhesion.

[0073] [Adhesion method according to the third embodiment] The conductive adhesive and the component used in the bonding method according to the third embodiment are the same as the conductive adhesive and the component used in the bonding method according to the first embodiment. The induction heating means for induction heating, the bonding method using the induction heating means, and the induction heating time in the bonding method according to the third aspect are the same as the induction heating means for induction heating, the bonding method using the induction heating means, and the induction heating time in the bonding method according to the first aspect.

[0074] <<Induction heating>> <T×Q / WD> In the bonding method according to the third aspect of the present invention, the induction heating time T (seconds), the induction heating power Q (kW), and the working distance WD (mm) are set to the following conditions: 1.1≦T×Q / WD≦14.0 Meet the following.

[0075] The induction heating power Q (kW) is the voltage of the high-frequency current flowing through the coil. The induction heating power Q can be set, for example, in the range of 3.5 kW to 35.0 kW. To facilitate adjustment of T×Q / WD, the induction heating frequency Q is preferably in the range of 3.5 kW to 10.5 kW. By adjusting the induction heating power Q, it is possible to control the heating during induction heating.

[0076] The working distance WD (mm) is the distance between the magnetic body, which is movable in a direction perpendicular to the space inside the coil, and the conductor in the space inside the coil. The working distance WD can be, for example, 3 mm or more, preferably 5 mm or more, and can be, for example, 30 mm or less, preferably 20 mm or less. Adjusting the working distance WD makes it possible to control the heating during induction heating.

[0077] In the bonding method according to the third aspect of the present invention, if "T×Q / WD" is less than 1.1, induction heating cannot be performed sufficiently, resulting in insufficient thermal curing of the conductive adhesive and the risk of poor adhesion. Also, if "T×Q / WD" is more than 14.0, induction heating becomes excessive, which can cause thermal damage to the components and / or adhesive, resulting in thermal damage to the components and poor adhesion.

[0078] [Adhesion method according to the fourth embodiment] The conductive adhesive, substrate, and component used in the bonding method according to the fourth embodiment are the same as the conductive adhesive, substrate, and component used in the bonding method according to the first embodiment. The induction heating means for induction heating, the bonding method using the induction heating means, and the induction heating time in the bonding method according to the fourth aspect are the same as the induction heating means for induction heating, the bonding method using the induction heating means, the induction heating time means, and the induction heating time in the bonding method according to the first aspect.

[0079] <<Absolute value of adhesive strength>> In the bonding method according to the fourth aspect, the absolute value (gf) of the adhesive strength between the bonded substrate and component is 3,000 gf (29.4 N; converted assuming 1,000 gf = 9.8 N) or more, preferably 4,000 gf or more. The upper limit of the absolute value of the adhesive strength is not particularly limited, but can be, for example, 300,000 gf or less. By having an absolute value of adhesive strength of 3,000 gf or more, preferably 4,000 gf or more, the substrate and component are firmly bonded together, and it is possible to prevent the component from falling off after bonding the component to the substrate. The absolute value of the adhesive strength (gf) can be obtained as the die shear bond strength (gf), and specifically, can be obtained by the method described in the examples below.

[0080] [Adhesion method according to the fifth embodiment] The conductive adhesive, substrate, and component used in the bonding method according to the fifth embodiment are the same as the conductive adhesive, substrate, and component used in the bonding method according to the first embodiment. The induction heating means for induction heating, the bonding method using the induction heating means, and the induction heating time in the bonding method according to the fifth aspect are the same as the induction heating means for induction heating, the bonding method using the induction heating means, and the induction heating time in the bonding method according to the first aspect.

[0081] <<Adhesive strength per unit area>> In the bonding method according to the fifth aspect, the adhesive strength (MPa) per unit area between the bonded substrate and component is 5.7 MPa or more. The upper limit of the adhesive strength per unit area is not particularly limited, but can be, for example, 57.5 MPa or less. When the adhesive strength per unit area is 5.7 MPa or more, preferably 7.5 MPa or more, the substrate and component are firmly bonded together, and it is possible to prevent the component from falling off after bonding the component to the substrate. The adhesive strength (MPa) per unit area can be obtained by the method described in the Examples below. [Example]

[0082] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0083] [Conductive adhesive] <Preparation of conductive adhesive AD1> 3.0 parts by mass of BPA-EP, 5.1 parts by mass of DCPD-EP, 1.4 parts by mass of MCLCA, 85.0 parts by mass of SCC, 4.8 parts by mass of MPGU, and 0.7 parts by mass of SiCA were added to a container and stirred and mixed to produce conductive adhesive AD1.

[0084] <Preparation of conductive adhesive AD2> 5.7 parts by mass of BPA-EP, 9.4 parts by mass of DCPD-EP, 2.6 parts by mass of MCLCA, 75.0 parts by mass of SCC, 5.9 parts by mass of epoxy resin amine adduct, and 1.4 parts by mass of SiCA were added to a container and stirred and mixed to produce conductive adhesive AD2.

[0085] <Conductive adhesive AD3> The conductive adhesive AD3 used was Fujikura Kasei's conductive adhesive "Dotite XA-910."

[0086] The components used in preparing the conductive adhesives AD1 and AD2 are as follows: BPA-EP: Bisphenol A epoxy resin (epoxy equivalent weight 948g / eq, glass transition temperature 100℃, solid at 25℃) [ka] (n in the structural formula is the number of repeating units, and is the value that results in a predetermined epoxy equivalent.) DCPD-EP: Dicyclopentadiene dimethanol diglycidyl ether (epoxy equivalent 165g / eq, boiling point 426℃, liquid at 25℃) [ka] MCLCA: Novacure HXA-3792 (Asahi Kasei Corporation, microcapsule-type latent hardener) SCC: ACFY-2 (Mitsui Mining & Smelting Co., Ltd., silver-coated copper powder, volume average particle size 5.4 μm, silver content 10% by mass) MPGU: 1,3,4,6-tetrakis(3-mercaptopropyl)glycoluril Epoxy resin amine adduct: Amine-based hardener (melting point 70-80°C, average particle size 5μm) SiCA: 3-glycidoxypropyltrimethoxysilane

[0087] [Base material] The substrates used in Examples A1 to A12, B1 to B28, Comparative Examples A1 to A7, B1 to B6, Reference Example A1 and Reference Example B1 are as follows. G: Glass plate (heat resistant up to 380°C, thickness 2.0 mm) PET: Polyethylene terephthalate resin film (heat resistant up to 150°C, thickness 0.1 mm) PC: Polycarbonate resin plate (heat resistant up to 130°C, thickness 2.0 mm) AC: Acrylic resin plate (heat resistant up to 90°C, thickness 2.0 mm) PEN: Polyethylene naphthalate resin film (heat resistant up to 180°C, thickness 0.1 mm) PVC: Polyvinyl chloride resin board (heat resistant up to 80°C, thickness 2.0 mm) PS: Polystyrene resin plate (heat resistant up to 80°C, thickness 2.0 mm) ABS: ABS (acrylonitrile-butadiene-styrene copolymer) resin plate (heat resistant up to 80°C, thickness 2.0 mm) PA: Polyamide resin plate (heat resistant up to 230°C, thickness 2.0 mm) PR: Phenolic resin plate (heat resistant up to 130°C, thickness 1.0 mm)

[0088] [evaluation] <Absolute value of adhesive strength> The substrate and component were bonded by induction heating or oven heating, and then left to stand at room temperature (25°C ± 5°C) for 1 hour. The absolute value of the adhesive strength between the substrate and the component (die shear bond strength: gf) was measured five times using a bonding tester PTR1102 (manufactured by Rhesca Corporation), and the average value was used as the absolute value of the adhesive strength. The absolute value of the adhesive strength was evaluated based on the following criteria. In the present invention, A and B ratings are pass, and C rating is fail. (Evaluation criteria) A: The absolute value of the adhesive strength (die shear bond strength) is 4,000 gf or more. B: The absolute value of the adhesive strength (die shear bond strength) is 3,000 gf or more and less than 4,000 gf. C: The absolute value of the adhesive strength (die shear bond strength) is less than 3,000 gf or the conductive adhesive does not cure thermally and adhesion is not possible.

[0089] <Adhesive strength per unit area> The substrate and component were bonded by induction heating or oven heating, and then left to stand at room temperature (25°C ± 5°C) for 1 hour. The adhesive strength (MPa) per unit area between the substrate and component was measured five times using a bonding tester PTR1102 (manufactured by Rhesca Corporation), and the average value was taken as the adhesive strength per unit area. The adhesive strength per unit area was evaluated based on the following criteria. In the present invention, A and B ratings were considered to be acceptable, and C rating was considered to be unacceptable. (Evaluation criteria) A: The adhesive strength per unit area is 7.5 MPa or more. B: The adhesive strength per unit area is 5.7 MPa or more and less than 7.5 MPa. C: The adhesive strength per unit area is less than 5.7 MPa or the conductive adhesive does not cure by heat and is not adhesive.

[0090] <Substrate damage> Before measuring the absolute value of the adhesive strength, the state of the substrate and the component after bonding by induction heating or oven heating was visually observed. The substrate damage was evaluated based on the following criteria. In the present invention, an A rating is a pass and a C rating is a fail. (Evaluation criteria) A: The substrate and the part are properly bonded, and no damage to the substrate is observed. C: The substrate is distorted and / or melted, causing the component (connector) to sink into the substrate, and damage to the substrate is observed.

[0091] [Example A1] Conductive adhesive AD1 was applied to a 2.0 mm thick glass substrate using a 2.3 mm x 1.1 mm, 100 μm thick metal mask. A component (a surface mount connector HH-1-G (manufactured by Mac Eight Corporation)) was placed on the glass substrate, and the substrate and component were bonded using an electromagnetic induction heating solder reflow (IH reflow) device manufactured by Wonder Future Corporation. The induction heating conditions were a working distance (WD) of 10 mm, an induction heating frequency (P) of 135 kHz (output 15% * maximum 900 kHz), and a heating time (T) of 3 seconds. The absolute adhesive strength was 8,391 gf (82.2 N; converted as 1,000 gf = 9.8 N), the absolute adhesive strength rating was A, the adhesive strength per unit area was 16.07 MPa, and the substrate damage rating was A. Table 1 also shows the absolute value of adhesive strength, the absolute value evaluation of adhesive strength, adhesive strength per unit area, adhesive strength evaluation per unit area, and substrate damage evaluation.

[0092] [Examples A2 to A12] The substrate and part were bonded in the same manner as in Example A1, except that the substrate was one listed in Table 1 and the induction heating conditions, namely, the working distance WD (mm), the induction heating frequency P (kHz), and the heating time T (seconds), were each listed in Table 1. Table 1 also lists the absolute value of the adhesive strength, the evaluation of the absolute value of the adhesive strength, the adhesive strength per unit area, the evaluation of the adhesive strength per unit area, and the evaluation of substrate damage.

[0093] [Comparative examples A1~A6] The substrate and component were bonded in the same manner as in Example A1, except that the conductive adhesive and substrate were as shown in Table 1, and the induction heating conditions, namely, working distance WD (mm), induction heating frequency P (kHz), and heating time T (seconds), were as shown in Table 1. Table 1 also shows the absolute value of the adhesive strength, the evaluation of the absolute value of the adhesive strength, the adhesive strength per unit area, and the evaluation of substrate damage. In Comparative Examples A1 to A5, the conductive adhesive was not thermally cured and adhesion was not possible, so it was impossible to measure the absolute value of the adhesive strength and the adhesive strength per unit area. In Comparative Example A6, the film melted, and stretching and breaking of the film occurred during measurement of the absolute value of the adhesive strength and the adhesive strength per unit area, making it impossible to measure the absolute value of the adhesive strength and the adhesive strength per unit area.

[0094] [Comparative example A7, reference example A1] Conductive adhesive AD1 was applied to the substrates listed in Table 1 using a metal mask with a pattern of 2.3 mm x 1.1 mm and a thickness of 100 μm. A component (surface mount connector HH-1-G (manufactured by Mac Eight Corporation)) was then placed on top, and the substrate was heated in an oven at 150°C for 1,800 seconds (30 minutes) to bond the component to the substrate. The absolute value of the adhesive strength, the absolute value evaluation of the adhesive strength, the adhesive strength per unit area, the adhesive strength evaluation per unit area, and the substrate damage evaluation are also listed in Table 1.

[0095] [Table 1]

[0096] From Table 1, a conductive adhesive containing a predetermined component is used, the induction heating time is 1 second or more and 300 seconds or less, and the induction heating time T (seconds), induction heating frequency P (kHz), and working distance WD (mm) are as follows: 30≦T×P / WD≦50 It can be seen that in the case of bonding methods that satisfy the above requirement (Examples A1 to A12), bonding with high absolute bond strength and bond strength per unit area can be achieved without damaging the substrate. Furthermore, when the substrate is glass, it is possible to achieve in just 3 seconds the same absolute bond strength and bond strength per unit area as when heated in an oven at 150°C for 30 minutes. On the other hand, when a conductive adhesive (AD3) not containing the predetermined component was used (Comparative Examples A1 and A2), the conductive adhesive was not thermally cured by induction heating and adhesion was not possible. In addition, the induction heating time T (seconds), induction heating frequency P (kHz) and working distance WD (mm) are as follows: 30≦T×P / WD≦50 When the bonding method did not satisfy the above (Comparative Examples A3 to A6), the conductive adhesive did not thermally cure and bonding was not possible (Comparative Examples A3 to A5), and the substrate damage evaluation was C (Comparative Example A6).

[0097] [Example B1] Conductive adhesive AD1 was applied to a 2.0 mm thick glass substrate using a 2.3 mm x 1.1 mm, 100 μm thick metal mask. A component (a surface mount connector HH-1-G (manufactured by Mac Eight Corporation)) was placed on the glass substrate, and the substrate and component were bonded using an electromagnetic induction heating solder reflow (IH reflow) device manufactured by Wonder Future Corporation. The induction heating conditions were a working distance (WD) of 10 mm, induction heating power (Q) of 5.3 kW (output 15% * maximum 35 kW), and heating time (T) of 3 seconds. The absolute adhesive strength was 8,391 gf (82.2 N; converted as 1,000 gf = 9.8 N), the absolute adhesive strength rating was A, the adhesive strength per unit area was 16.07 MPa, and the substrate damage rating was A. Table 2 also shows the absolute value of adhesive strength, the absolute value evaluation of adhesive strength, adhesive strength per unit area, adhesive strength evaluation per unit area, and substrate damage evaluation.

[0098] [Examples B2 to B28] The substrate and part were bonded in the same manner as in Example B1, except that the substrate was one shown in Table 2 and the induction heating conditions, namely, the working distance WD (mm), induction heating power Q (kW), and heating time T (seconds), were each shown in Table 2. Table 2 also shows the absolute value of the adhesive strength, the evaluation of the absolute value of the adhesive strength, the adhesive strength per unit area, the evaluation of the adhesive strength per unit area, and the evaluation of substrate damage.

[0099] [Comparative Examples B1 to B5] The substrate and component were bonded in the same manner as in Example B1, except that the conductive adhesive and substrate were as shown in Table 2, and the induction heating conditions, namely, working distance WD (mm), induction heating power Q (kW), and heating time T (seconds), were as shown in Table 2. Table 2 also lists the absolute value of adhesive strength, absolute value evaluation of adhesive strength, adhesive strength per unit area, adhesive strength per unit area evaluation, and substrate damage evaluation. In Comparative Examples B1 to B5, the conductive adhesive was not thermally cured and adhesion was not possible, so it was impossible to measure the absolute value of the adhesive strength and the adhesive strength per unit area.

[0100] [Comparative example B6, reference example B1] Conductive adhesive AD1 was applied to the substrates listed in Table 2 using a metal mask with a pattern of 2.3 mm x 1.1 mm and a thickness of 100 μm. Next, a component (surface mount connector HH-1-G (manufactured by Mac Eight Corporation)) was placed on top, and the substrate was placed in an oven and heated at 150°C for 1800 seconds (30 minutes) to bond the component to the substrate. The absolute value of the adhesive strength, the absolute value evaluation of the adhesive strength, the adhesive strength per unit area, the adhesive strength evaluation per unit area, and the substrate damage evaluation are also listed in Table 2.

[0101] [Table 2]

[0102] From Table 2, it can be seen that a conductive adhesive containing a predetermined component is used, the induction heating time is 1 second or more and 300 seconds or less, and the induction heating time T (seconds), induction heating power Q (kW), and working distance WD (mm) are as follows: 1.1≦T×Q / WD≦2.0 It can be seen that in the case of bonding methods that satisfy the above condition (Examples B1 to B11, B27, and B28), bonding with high absolute bond strength and bond strength per unit area can be achieved without damaging the substrate. Furthermore, when the substrate is glass, it is possible to achieve in just 3 seconds the same absolute bond strength and bond strength per unit area as when heated in an oven at 150°C for 30 minutes.

[0103] From Table 2, a conductive adhesive containing a predetermined component is used, a glass substrate is used as the substrate, the induction heating time is 1 second or more and 300 seconds or less, and the induction heating time T (seconds), induction heating power Q (kW), and working distance WD (mm) are as follows: 1.1≦T×Q / WD≦14.0 It can be seen that in the case of bonding methods that satisfy the above requirement (Examples B1 and B12 to B26), bonding with high absolute bond strength and bond strength per unit area can be achieved without damaging the substrate. Furthermore, it is possible to achieve the same absolute bond strength and bond strength per unit area in just 3 seconds as when heated in an oven at 150°C for 30 minutes.

[0104] On the other hand, when a conductive adhesive (AD3) not containing the predetermined component was used (Comparative Examples B1 and B2), the conductive adhesive was not thermally cured by induction heating and adhesion was not possible. In addition, the induction heating time T (seconds), induction heating power Q (kW) and working distance WD (mm) are as follows: 1.1≦T×Q / WD≦2.0 In the case of the bonding method that did not satisfy the above (Comparative Examples B3 to B5), the conductive adhesive did not thermally cure and bonding was not possible.

Claims

1. 1. A bonding method for bonding a component to a substrate by induction heating using a conductive adhesive containing (A) an epoxy resin, (B) a microcapsule-type latent curing agent, and (C) a conductive powder, comprising: The induction heating time T is 1 second or more and 300 seconds or less, The induction heating time T (seconds), the induction heating frequency P (kHz), and the working distance WD (mm) in the induction heating are as follows: 30≦T×P / WD≦50 The bonding method satisfies the above.

2. 1. A bonding method for bonding a component to a substrate by induction heating using a conductive adhesive containing (A) an epoxy resin, (B) a microcapsule-type latent curing agent, and (C) a conductive powder, comprising: The induction heating time T is 1 second or more and 300 seconds or less, The induction heating time T (seconds), induction heating power Q (kW), and working distance WD (mm) in induction heating are as follows: 1.1≦T×Q / WD≦2.0 The bonding method satisfies the above.

3. A bonding method for bonding a component to a glass substrate by induction heating using a conductive adhesive containing (A) an epoxy resin, (B) a microcapsule-type latent curing agent, and (C) a conductive powder, the method comprising: The induction heating time T is 1 second or more and 300 seconds or less, The induction heating time T (seconds), induction heating power Q (kW), and working distance WD (mm) in induction heating are as follows: 1.1≦T×Q / WD≦14.0 The bonding method satisfies the above.

4. 1. A bonding method for bonding a component to a substrate by induction heating using a conductive adhesive containing (A) an epoxy resin, (B) a microcapsule-type latent curing agent, and (C) a conductive powder, comprising: The bonding method, wherein the induction heating time T is 1 second or more and 300 seconds or less, and the absolute value (gf) of the adhesive strength between the bonded substrate and component is 3,000 gf or more.

5. 1. A bonding method for bonding a component to a substrate by induction heating using a conductive adhesive containing (A) an epoxy resin, (B) a microcapsule-type latent curing agent, and (C) a conductive powder, comprising: The bonding method, wherein the induction heating time T is 1 second or more and 300 seconds or less, and the adhesive strength (MPa) per unit area of ​​the bonded substrate and component is 5.7 MPa or more.

6. 6. The bonding method according to any one of claims 1, 2, 4, and 5, wherein the substrate comprises one or more selected from the group consisting of ceramics, glass, polyimide resin, polyphenylene sulfide resin, polysulfone resin, polyether ether ketone resin, polyether sulfone resin, polyphenylene ether resin, polyacetal resin, polyoxymethylene resin, cycloolefin polymer, polybutylene terephthalate resin, polyamide-imide resin, polyetherimide resin, polyethernitrile resin, polyarylate resin, liquid crystal polymer, polyethylene terephthalate resin, polyethylene naphthalate resin, acrylic resin, polycarbonate resin, polyvinyl chloride resin, fluororesin, acrylonitrile-butadiene-styrene resin, acrylonitrile-styrene resin, polyamide resin, polystyrene resin, phenolic resin, epoxy resin, urethane resin, maleimide resin, cyanate resin, urea resin, melamine resin, polyolefin resin, thermoplastic elastomer, paper, textile, composites of one or more of these, and mixtures of one or more of these.

7. The bonding method according to any one of claims 1 to 5, wherein the conductive adhesive further contains (D) a thiol compound.

Images