Connection material, connection structure, and method for manufacturing connection structure

Abstract

Provided are a connection material, a connection structure, and a method for manufacturing the connection structure, with which excellent connection reliability and repairability can be obtained. The connecting material contains an ionically polymerizable compound, an ionic polymerization initiator, and a caprolactone derivative, and the content of the caprolactone derivative is 5-40 parts by mass per 100 parts by mass of the total amount of the ionically polymerizable compound and the caprolactone derivative. As a result, the glass transition temperature of the cured product can be adjusted, and excellent connection reliability and repairability can be obtained.

Description

Technical Field

[0001] The present technology relates to a bonding material for uses such as COG (Chip On Glass), a bonded structure using the bonding material, and a method for manufacturing the bonded structure. This application claims priority based on Japanese Patent Application No. 2022-171252 filed in Japan on October 26, 2022, and this application is incorporated herein by reference. Background Art

[0002] Conventionally, for example, in a bonding material for connecting an LCD (Liquid Crystal Display) driver IC (Integrated Circuit) to a display panel, in order to obtain characteristics such as a high elastic modulus and a high glass transition temperature (Tg) to maintain high reliability, an epoxy compound, an oxetane compound, etc. have been used. On the other hand, in order to reuse expensive components such as a display panel or a driver IC, reparability for easily removing the cured bonding material has also been required (for example, refer to Patent Documents 1-4).

[0003] However, for example, an epoxy resin cured product based on cationic polymerization is difficult to remove due to characteristics such as a high elastic modulus and a high glass transition temperature (Tg). Generally, by lowering the glass transition temperature of the cured product, reparability is improved, but at the same time, a decrease in connection reliability is a concern, so it is difficult to achieve both excellent connection reliability and reparability.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-079313;

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2010-102859;

[0008] Patent Document 3: Japanese Patent Application Laid-Open No. 10-204153;

[0009] Patent Document 4: Japanese Patent Application Laid-Open No. 2001-093939. Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] The present technology is a technology for solving the above problems, and provides a bonding material, a bonded structure, and a method for manufacturing the bonded structure that can achieve excellent connection reliability and reparability.

[0012] Means for Solving the Problems

[0013] The present inventors conducted in-depth research and found that the following connecting material, connecting structure, and manufacturing method of the connecting structure can achieve the above object, thus completing the present technology.

[0014] [1] A connecting material containing: an ionically polymerizable compound, an ionic polymerization initiator, and a caprolactone derivative,

[0015] The content of the caprolactone derivative is 5 to 40 parts by mass relative to the total amount of 100 parts by mass of the ionically polymerizable compound and the caprolactone derivative.

[0016] [2][1] The connecting material according to [1], wherein the content of the caprolactone derivative is 5 to 25 parts by mass relative to the total amount of 100 parts by mass of the ionically polymerizable compound and the caprolactone derivative.

[0017] [3][1] The connecting material according to [1], wherein the glass transition temperature after curing of the connecting material is 170 to 195 °C.

[0018] [4][1] The connecting material further contains a thermoplastic resin and an insulating filler,

[0019] The total content of the ionically polymerizable compound and the caprolactone derivative is 10 to 50 wt%.

[0020] [5][1] The connecting material according to [1], wherein the ionically polymerizable compound contains an epoxy compound or an oxetane compound,

[0021] The ionic polymerization initiator is a cationic polymerization initiator.

[0022] [6][1] The connecting material according to [1], wherein the molecular weight per functional group equivalent of the caprolactone derivative is 100 to 3000.

[0023] [7][1] The connecting material according to [1], wherein the molecular weight per functional group equivalent of the caprolactone derivative is 100 to 1000.

[0024] [8][1] The connecting material according to [1], wherein the caprolactone derivative is one or more selected from polycaprolactone diol, polycaprolactone triol, and polycaprolactone tetrol.

[0025] [9][1] The connecting material further contains conductive particles.

[0026]

[10] A connecting structure including: a first electronic component, a second electronic component, and an adhesive cured film that bonds the first electronic component and the second electronic component,

[0027] The adhesive cured film is formed by curing a connecting material, and the connecting material contains: an ionic polymerizable compound, an ionic polymerization initiator, and a caprolactone derivative. The content of the caprolactone derivative is 5 to 40 parts by mass relative to the total amount of 100 parts by mass of the ionic polymerizable compound and the caprolactone derivative.

[0028]

[11]

[10] The connecting structure described above, wherein the connecting material further contains conductive particles.

[0029]

[12] A method for manufacturing a connecting structure, which includes:

[0030] A disposing step of disposing a first electronic component and a second electronic component with a connecting material therebetween. The connecting material contains: an ionic polymerizable compound, an ionic polymerization initiator, and a caprolactone derivative. The content of the caprolactone derivative is 5 to 40 parts by mass relative to the total amount of 100 parts by mass of the ionic polymerizable compound and the caprolactone derivative; and

[0031] A curing step of pressing the second electronic component onto the first electronic component by using a pressing tool while curing the connecting material.

[0032]

[13]

[12] The method for manufacturing a connecting structure described above, wherein the connecting material further contains conductive particles.

[0033] Advantages of the Invention

[0034] According to the present technology, excellent connection reliability and reparability can be obtained. Description of the Drawings

[0035] Figure 1 Figure 1 (A) is a diagram for explaining the crosslinked structure after cationic polymerization of an ionic polymerizable compound, Figure 1 (B) is a diagram for explaining the crosslinked structure after ionic polymerization of an ionic polymerizable compound and a caprolactone derivative.

[0036] Figure 2 Figure 2 is a diagram for explaining the method for manufacturing the connecting structure according to the present embodiment, Figure 2 (A) shows the disposing step (S1), Figure 2 (B) shows the curing step (S2).

[0037] Figure 3 Figure 3 is a chart showing the glass transition temperature (Tg) with respect to the content of the caprolactone derivative. Detailed Description of the Embodiment

[0038] Hereinafter, while referring to the attached​​​​​​Figure 1 The implementation examples of the present technology will be described in detail in the following order.

[0039] 1. Connecting material;

[0040] 2. Connecting structure and manufacturing method of the connecting structure;

[0041] 3. Examples.

[0042] <1. Connecting material>

[0043] The connecting material involved in this implementation example contains: an ionically polymerizable compound, an ionic polymerization initiator, and a caprolactone derivative. The connecting material can be either in the form of a film or a paste. Considering the ease of operation, a film form is preferred, and considering the cost, a paste form is preferred. In addition, as the curing type of the connecting material, examples include: heat-curing type, photo-curing type, photo-thermal combined curing type, etc., which can be appropriately selected according to the use. In addition, as the ionic polymerization type of the connecting material, cationic polymerization or anionic polymerization can be appropriately selected according to the use.

[0044] (Ionically polymerizable compound)

[0045] As the ionically polymerizable compound, for example, the following can be cited: epoxy compounds, oxetane compounds, etc. In order to obtain a crosslinked structure through a curing reaction, the ionically polymerizable compound preferably has 2 or more and 5 or less epoxy groups at the ends.

[0046] The epoxy compound preferably has 2 or more and 5 or less epoxy groups at the ends. For example, one kind can be used alone or two or more kinds can be used in combination from the following: alicyclic epoxy compounds, glycidyl ether type epoxy compounds, glycidyl ester type epoxy compounds, bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, dicyclopentadiene type epoxy compounds, novolak phenol type epoxy compounds, biphenyl type epoxy compounds, naphthalene type epoxy compounds, etc. As specific examples of the alicyclic epoxy compound having a cycloolefin oxide structure, for example, the product names of Daicel Corporation "CELLOXIDE 8010 ((3,3’,4,4’-diepoxy) dicyclohexyl)", "CELLOXIDE 2021P (3,4-epoxycyclohexanecarboxylic acid 3’,4’-epoxycyclohexylmethyl ester)", etc. can be cited.

[0047] The oxetane compound preferably has 2 or more and 5 or less oxetanyl groups at the ends. For example, one kind can be used alone or two or more kinds can be used in combination from the following: biphenyl-type oxetane compounds, xylene-type oxetane compounds, silsesquioxane-type oxetane compounds, ether-type oxetane compounds, novolak-type oxetane compounds, silicate-type oxetane compounds, etc. As a specific example of the biphenyl-type oxetane compound, "OXBP (4,4'-bis[(3-ethyl-3-oxetanylmethyl)biphenyl])" manufactured by Ube Industries, Ltd. can be cited, etc.

[0048] The content of the ionic polymerizable compound is preferably, for example, 11 to 48 wt% of the binder as the resin component, more preferably 15 to 43 wt%, and further preferably 19 to 38 wt%. If the content of the cationic polymerizable compound is too large, there is a tendency for the curing shrinkage to increase.

[0049] As the ionic polymerization initiator, a cationic polymerization initiator or an anionic polymerization initiator is used according to the ionic polymerization type of cationic polymerization or anionic polymerization.

[0050] (Cationic polymerization initiator)

[0051] As the cationic polymerization initiator, for example, one kind can be used alone or two or more kinds can be used in combination from the following: onium salt type acid generators such as sulfonium salts, ammonium salts, phosphonium salts, etc. Among these, in order to improve the storage life, a quaternary ammonium salt-based thermal acid generator is preferably used. As the quaternary ammonium salt-based thermal acid generator, salts of quaternary ammonium cations and hexafluoroantimonate anions, hexafluorophosphate anions, trifluoromethanesulfonate anions, perfluorobutanesulfonate anions, dinonylnaphthalenesulfonate anions, dinonylnaphthalenesulfonate anions, p-toluenesulfonate anions, dodecylbenzenesulfonate anions, or tetrakis(pentafluorophenyl)borate anions can be cited. In addition, as the quaternary ammonium cation, NR 1 R 2 R 3 R 4 + represents the cation. Here, R 1 、R 2 、R 3 and R 4 are linear, branched or cyclic alkyl or aryl groups having 1 to 12 carbon atoms, and may each have a hydroxyl group, a halogen, an alkoxy group, an amino group, an ester group, etc. As the quaternary ammonium salt-based thermal acid generator, "K-PURE CXC-1821" with the product name of King Industries can be cited, etc.

[0052] (Anionic polymerization initiator)

[0053] Anionic polymerization initiators can be used alone or in combination of two or more selected from the following: organic acid dihydrazide, dicyandiamide, amine compounds, polyamide-amine compounds, cyanate ester compounds, phenolic resins, acid anhydrides, carboxylic acids, tertiary amine compounds, imidazoles, Lewis acids, Bronsted salts, polythiol-based curing agents, urea resins, melamine resins, isocyanate compounds, blocked isocyanate compounds, etc. Among these, a microcapsule-type latent curing agent obtained by using an imidazole-modified product as a core and coating its surface with polyurethane is preferably used. As a specific example available on the market, "NOVACURE 3941HP" with the trade name of Asahi Kasei E-Materials Co., Ltd. can be cited, etc.

[0054] The content of the ionic polymerization initiator is preferably, for example, 1 to 20 wt% of the binder as the resin component, more preferably 3 to 15 wt%, and still more preferably 5 to 10 wt%.

[0055] (Caprolactone derivative)

[0056] The caprolactone derivative is, for example, a polycaprolactone polyol obtained by ring-opening polymerization of ε-caprolactone and an alcohol compound, and preferably has two or more hydroxyl groups at the terminal. As the polycaprolactone polyol, for example, polycaprolactone diol having two hydroxyl groups at the terminal, polycaprolactone triol having three hydroxyl groups at the terminal, polycaprolactone tetrol having four hydroxyl groups at the terminal, etc. can be cited, and one kind can be used alone or two or more kinds can be used in combination. As a specific example of the polycaprolactone polyol, for example, products of the "PLACCEL" series of Daicel Corporation can be cited, etc.

[0057] The molecular weight per functional group equivalent of the caprolactone derivative is preferably 100 to 3000, more preferably 100 to 2000, and still more preferably 100 to 1000. If the molecular weight per functional group equivalent of the caprolactone derivative becomes smaller, the change amount of the glass transition temperature (Tg) with respect to the content of the caprolactone derivative tends to become larger.

[0058] The total content of the ionic polymerizable compound and the caprolactone derivative is preferably, for example, 15 to 50 wt% of the binder as the resin component, more preferably 20 to 45 wt%, and still more preferably 25 to 40 wt%. In addition, with respect to 100 parts by mass of the total amount of the ionic polymerizable compound and the caprolactone derivative, the content of the caprolactone derivative is preferably 5 to 40 parts by mass, more preferably 5 to 30 parts by mass, and still more preferably 5 to 25 parts by mass. If the content of the caprolactone derivative increases with respect to 100 parts by mass of the total amount of the ionic polymerizable compound and the caprolactone derivative, the glass transition temperature (Tg) tends to decrease, and the reparability tends to increase.

[0059] In addition, the content of the caprolactone derivative is preferably, for example, 1 to 10 wt% of the binder as the resin component, more preferably 1 to 8 wt%, and still more preferably 2 to 6 wt%. By adding a small amount of the caprolactone derivative, the glass transition temperature (Tg) can be precisely controlled.

[0060] The glass transition temperature (Tg) after curing of the bonding material is preferably 150 to 195°C, more preferably 155 to 195°C, and still more preferably 160 to 195°C. The higher the glass transition temperature (Tg), the more likely it is to obtain excellent bonding reliability.

[0061] Figure 1 (A) is a diagram for explaining the crosslinked structure after cationic polymerization of the ion-polymerizable compound. Figure 1 (B) is a diagram for explaining the crosslinked structure after ionic polymerization of the ion-polymerizable compound and the caprolactone derivative. As Figure 1 shown in (A), the crosslinked structure after cationic polymerization of the ion-polymerizable compound is composed of (a) a network derived from an epoxy compound or an oxetane compound. On the other hand, as Figure 1 shown in (A), the crosslinked structure after ionic polymerization of the ion-polymerizable compound and the caprolactone derivative is composed of incorporating (b) polycaprolactone polyol into the network (a) derived from an epoxy compound or an oxetane compound.

[0062] Generally, the denser the crosslinked structure, the higher the Tg and elastic modulus of the cured product. However, since the caprolactone derivative has a hydroxyl group at the end, it reacts as a monomer during the ionic polymerization reaction and is incorporated into the crosslinked structure. Since the caprolactone derivative has the effect of reducing the crosslink density of the flexible long-chain alkyl structure, the Tg can be reduced by adding a small amount, precise control of Tg can be achieved, and excellent bonding reliability and reparability can be balanced.

[0063] (Polymer)

[0064] In order to improve film-forming properties, connection reliability, etc., the connection material may further contain a polymer as a binder. Examples of the polymer include: bisphenol A type phenoxy resin, phenoxy resin having a fluorene skeleton, polystyrene, polyacrylonitrile, polyphenylene sulfide, polytetrafluoroethylene, polycarbonate, etc. These can be used alone or in combination of two or more. Among these, from the viewpoints of film-forming properties, connection reliability, etc., it is preferable to use a phenoxy resin as a thermoplastic resin. The phenoxy resin is a polyhydroxy polyether synthesized from bisphenols and epichlorohydrin. Specific examples of the phenoxy resin include product names such as "FX293", "YP50", "YP70", etc. of Nippon Steel & Sumikin Chemical Co., Ltd. It should be noted that as a method for lowering Tg, a method of using a polymer having a flexible skeleton can be considered. However, since the polymer affects various physical properties such as film-forming properties and connection reliability, it is difficult to precisely control Tg by selecting a polymer while considering these physical properties.

[0065] The content of the polymer is preferably, for example, 10 to 50 wt% of the binder as the resin component, more preferably 15 to 45 wt%, and still more preferably 20 to 30 wt%.

[0066] (Insulating filler)

[0067] In order to adjust the minimum melt viscosity, the connection material may further contain an insulating filler as a binder. Examples of the insulating filler include: inorganic fillers such as silica, alumina, calcium carbonate, titanium oxide, etc.; organic fillers such as acrylic rubber, silicone, etc. These can be used alone or in combination of two or more. Among these, it is preferable to use silica. Specific examples of silica include product names such as "AEROSIL R202" of Nippon Aerosil Co., Ltd., "ADMANANO" of Admatechs Co., Ltd., etc.

[0068] The content of the insulating filler is preferably, for example, 5 to 60 wt% of the binder as the resin component, more preferably 10 to 55 wt%, and still more preferably 20 to 50 wt%. If the content of the filler is large, there is a tendency for the minimum melt viscosity to increase. If the content of the filler is small, there is a tendency for the minimum melt viscosity to decrease. In addition, the average particle size of the filler is preferably 1 to 500 nm, more preferably 10 to 300 nm, and still more preferably 20 to 100 nm.

[0069] (Silane coupling agent)

[0070] In order to improve the adhesiveness at the interface with the inorganic material, the connecting material may further contain a silane coupling agent as an adhesive. Examples of the silane coupling agent include epoxy-based, methacryloxy-based, amino-based, vinyl-based, mercapto / sulfide-based, urea-based, etc., and these can be used alone or in combination of two or more. Specific examples of the epoxy-based silane coupling agent include "A-187" (product name of Momentive Performance Materials Japan LLC); "KBM-4803" (product name of Shin-Etsu Chemical Co., Ltd.), etc.

[0071] The content of the silane coupling agent is preferably, for example, 0.1 to 10 wt% of the adhesive as the resin component, more preferably 0.1 to 5 wt%, and still more preferably 0.5 to 3 wt%.

[0072] (Conductive adhesive)

[0073] The connecting material may be a conductive adhesive containing conductive particles in the adhesive. The conductive adhesive may be either a film-like conductive film or a paste-like conductive paste. In addition, the conductive adhesive can also be used as an anisotropic conductive adhesive. The anisotropic conductive adhesive may be either a film-like anisotropic conductive film (ACF: Anisotropic Conductive Film) or a paste-like anisotropic conductive paste (ACP: Anisotropic conductive paste). Considering the ease of operation, a film-like form is preferred, and considering the cost, a paste-like form is preferred.

[0074] As the conductive particles, known conductive particles used in anisotropic conductive films can be appropriately selected and used. For example, nickel (melting point 1455 °C), copper (melting point 1085 °C), silver (melting point 961.8 °C), gold (melting point 1064 °C), palladium (melting point 1555 °C), tin (melting point 231.9 °C), nickel boride (melting point 1230 °C), ruthenium (melting point 2334 °C), solder such as tin alloy and other metal particles can be cited. In addition, for example, metal-coated metal particles obtained by coating the surface of metal particles with metals such as nickel, copper, silver, gold, palladium, tin, nickel boride, ruthenium, etc. can be cited. In addition, for example, metal-coated resin particles obtained by coating the surface of resin particles such as polymers having at least one monomer selected from polyamide, polybenzoguanamine, styrene, and divinylbenzene as monomer units with metals such as nickel, copper, silver, gold, palladium, tin, nickel boride, ruthenium, etc. can be cited. In addition, for example, metal-coated inorganic particles obtained by coating the surface of inorganic particles such as silica, alumina, barium titanate, zirconia, carbon black, silicate glass, borosilicate glass, lead glass, soda-lime glass, and aluminosilicate glass with metals such as nickel, copper, silver, gold, palladium, tin, nickel boride, ruthenium, etc. can be cited. In addition, the metal coating layer of the metal-coated resin particles and the metal-coated inorganic particles can be a single layer or multiple layers of different metals. In addition, an insulating coating treatment can also be performed by coating these conductive particles with insulating particles such as a resin layer, resin particles, or inorganic particles. In this case, the particle diameter of the conductive particles does not include the part of the insulating coating treatment.

[0075] The particle diameter of the conductive particles can be appropriately changed according to the optical elements to be installed, the electrodes of the wiring substrate, the area of the bumps, etc., but is preferably 1 to 30 μm, more preferably 1 to 10 μm, and particularly preferably 1 to 5 μm. For the particle diameter, more than 200 can be measured by microscopic observation (optical microscope, metallurgical microscope, electron microscope, etc.), and the average value is set.

[0076] In addition, as the shape of the conductive particles, spherical, ellipsoidal, spike-shaped, irregular shapes, etc. can be cited. Among these, from the perspective of easily controlling the particle diameter or particle size distribution, spherical conductive particles are preferred. In addition, in order to improve the connectivity, protrusions can also be provided on the surface of the conductive particles.

[0077] The anisotropic conductive film is preferably formed by arranging the conductive particles in the plane direction. By arranging the conductive particles in the plane direction, the particle surface density becomes uniform, and the conductivity and insulation can be improved. The state of arranging the conductive particles in the plane direction, for example, can include a planar lattice pattern having one or more arrangement axes in which the conductive particles are arranged at a predetermined interval in a predetermined direction, and can include a rhombic lattice, a hexagonal lattice, a square lattice, a rectangular lattice, a parallelepiped lattice, etc. In addition, the planar arrangement of the conductive particles can be random or can have multiple regions with different planar lattice patterns.

[0078] The particle surface density of the anisotropic conductive film can be appropriately designed according to the electrode size of the connection object, and the lower limit of the particle surface density can be set to 500 particles / mm 2 or more, 20,000 particles / mm 2 or more, 40,000 particles / mm 2 or more, 50,000 particles / mm 2 or more, and the upper limit of the particle surface density can be set to 1,500,000 particles / mm 2 or less, 1,000,000 particles / mm 2 or less, 500,000 particles / mm 2 or less, 100,000 particles / mm 2 or less. Thus, excellent conductivity and insulation can be obtained even when the electrode size of the connection object is small. The particle surface density of the anisotropic conductive film is the density of the arrangement part of the conductive particles during film formation in the manufacturing process. When obtaining the particle number density from multiple single chips, the particle surface density can be obtained based on the area and the number of particles obtained by removing the intervals between the single chips from the area including the single chips and the intervals.

[0079] The anisotropic conductive film is formed into a film shape, and it is easy to dispose the anisotropic conductive film on the substrate. From the viewpoint of operability, a release film such as a polyethylene terephthalate film may be disposed on one or both surfaces of the anisotropic conductive film. In addition, the anisotropic conductive film may be laminated with an adhesive layer or an adhesive layer that does not contain conductive particles, and the number of layers or the laminated surface can be appropriately selected according to the object or purpose.

[0080] The film thickness of the anisotropic conductive film can be appropriately changed according to the height of the electrodes or bumps of the optical element or wiring substrate to be installed, as long as it is within 1 to 10 times the particle diameter, preferably 1 μm or more and 10 μm or less, more preferably 1 μm or more and 6 μm or less, and further preferably 2 μm or more and 4 μm or less. The film thickness can be measured using a known micrometer or digital thickness gauge. For example, the film thickness can be measured at 10 or more locations and averaged.

[0081] As a method for manufacturing the anisotropic conductive film, for example, there can be mentioned: a method of coating a solution of an anisotropic conductive adhesive on a substrate and drying it; or a method of forming an adhesive layer that does not contain conductive particles on a substrate and fixing conductive particles on the obtained adhesive layer, etc.

[0082] <2. Connection structure and manufacturing method of connection structure>

[0083] The connection structure according to this embodiment includes: a first electronic component, a second electronic component, and an adhesive cured film that bonds the first electronic component and the second electronic component.

[0084] In addition, the manufacturing method of the connection structure according to the present embodiment includes: a placement process of placing a first electronic component and a second electronic component with a connection material therebetween; and a curing process of curing the connection material while pressing the second electronic component onto the first electronic component using a crimping tool.

[0085] Since the connection structure and the manufacturing method of the connection structure according to the present embodiment use a connection material containing an ionically polymerizable compound, an ionic polymerization initiator, and a caprolactone derivative, excellent connection reliability and reparability can be obtained.

[0086] Hereinafter, a manufacturing method of a connection structure using a thermosetting anisotropic conductive film as a connection material will be described. It should be noted that since the anisotropic conductive film is the same as the above, the description thereof will be omitted here.

[0087] Figure 2 It is a diagram for explaining the manufacturing method of the connection structure according to the present embodiment, Figure 2 (A) represents the placement process (S1), Figure 2 (B) represents the curing process (S2).

[0088] [Placement process (S1)]

[0089] As Figure 1 shown in (A), in the placement process (S1), the second electronic component 20 is placed on the first electronic component 10 with an anisotropic conductive film 30 containing an ionically polymerizable compound, an ionic polymerization initiator, and a caprolactone derivative therebetween.

[0090] The first electronic component 10 includes a first terminal row 11, and the second electronic component 20 includes a second terminal row 21 opposed to the first terminal row 11. There are no particular limitations on the first electronic component 10 and the second electronic component 20, and they can be appropriately selected according to the purpose. As the first electronic component 10, for example, there can be mentioned: LCD (Liquid Crystal Display) panels, flat panel displays (FPD) such as organic EL (OLED) for uses such as touch panel uses, wiring substrates, printed wiring boards (PWB), etc. There are no particular limitations on the material of the printed wiring board. For example, it can be glass epoxy resin such as FR-4 substrate, and plastics such as thermoplastic resins, ceramics, etc. can also be used. In addition, as the wiring substrate, there can be mentioned: glass substrates, plastic substrates, etc. In addition, as the second electronic component 20, for example, there can be mentioned: IC (Integrated Circuit), flexible substrate (FPC: Flexible Printed Circuits), tape carrier package (TCP) substrate, chip on film (COF) in which an IC is mounted on an FPC, etc.

[0091] [Solidification Process (S2)]

[0092] In the solidification process (S2), the second electronic component 20 is pressed against the first electronic component 10 using a crimping tool 40 while heating and crimping. Additionally, in the solidification process (S2), using the crimping tool 40, it is preferably carried out at a temperature of 200 °C or lower, more preferably at a temperature of 180 °C or lower, and further preferably at a temperature of 150 °C or lower. Thus, the adhesive of the anisotropic conductive film melts due to the heat of the crimping tool, and the second electronic component is fully pressed in using the crimping tool 40, and the conductive particles 31 are clamped between the first terminal row 11 and the second terminal row 21. Additionally, through heat curing of the adhesive, the first electronic component 10 and the second electronic component 20 are bonded together.

[0093] Furthermore, in the solidification process (S2), a buffer material can be used between the crimping tool 40 and the second electronic component 20. As the buffer material, polytetrafluoroethylene (PTFE: polytetrafluoroethylene), polyimide, glass cloth, silicone rubber, etc. can be used.

[0094] Examples

[0095] <3. Examples>

[0096] In this example, as a form of the connection material, a cationic polymerization type anisotropic conductive film was fabricated. Additionally, using the anisotropic conductive film, an IC chip was thermally crimped onto a glass substrate to fabricate a connection structure. Moreover, the conduction resistance of the connection structure was measured before and after HAST (High Accelerated Stress Test), and the connection reliability was evaluated. Additionally, the chip shear strength of the IC chip was measured to evaluate the reparability of the anisotropic conductive film after the IC chip was peeled off.

[0097] [Fabrication of Double - Layer Type Anisotropic Conductive Film]

[0098] As shown in Table 1, a thermoplastic resin, a filler, an ionic polymerizable compound, a caprolactone derivative, a silane coupling agent, and a cationic polymerization initiator were blended in specified mass parts to fabricate a first adhesive layer with a thickness of 10 μm. Additionally, as shown in Table 1, a thermoplastic resin, a filler, an ionic polymerizable compound, a caprolactone derivative, a silane coupling agent, and a cationic polymerization initiator were blended in specified mass parts to fabricate a second adhesive layer with a thickness of 5 μm, and conductive particles with an average particle diameter of 3.2 μm were arranged on the second adhesive layer at a surface density of 28000 pieces / mm 2 to fabricate an anisotropic conductive layer. Moreover, the first adhesive layer and the anisotropic conductive layer were laminated to fabricate a double - layer type anisotropic conductive film.

[0099] [Fabrication of Single-Layer Anisotropic Conductive Film]

[0100] As shown in Table 1, a resin composition was prepared by blending a thermoplastic resin, a filler, an ion-polymerizable compound, a caprolactone derivative, a silane coupling agent, and a cationic polymerization initiator in specified parts by mass. In the resin composition, conductive particles (average particle size: 3.2 μm) were adjusted to be 15 wt% with respect to the total amount of the resin mixture and the conductive particles, and an anisotropic conductive film with a thickness of 7 μm was fabricated.

[0101] Thermoplastic resin:

[0102] Phenoxy resin FX293 (Nippon Steel Chemical & Materials Co., Ltd.)

[0103] Filler:

[0104] Fumed silica AEROSIL R202 (Nippon AEROSIL Co., Ltd.)

[0105] Ion-polymerizable compound: Alicyclic epoxy compound CELLOXIDE 8010 (Daicel Corporation, difunctional)

[0106] Caprolactone derivative:

[0107] Polycaprolactone diol L205AL (Daicel Corporation, difunctional, molecular weight 500), polycaprolactone diol L220AL (Daicel Corporation, difunctional, molecular weight 2000), polycaprolactone triol PCL305 (Daicel Corporation, trifunctional, molecular weight 550), polycaprolactone triol PCL312 (Daicel Corporation, trifunctional, molecular weight 1250), polycaprolactone triol PCL320 (Daicel Corporation, trifunctional, molecular weight 2000)

[0108] Silane coupling agent:

[0109] A-187 (Momentive Performance Materials Japan LLC)

[0110] Cationic polymerization initiator:

[0111] Thermal acid generator K-PURE CXC-1821 (King Industries, Inc.) using a quaternary ammonium salt-based onium salt

[0112] [Measurement of Glass Transition Temperature (Tg)]

[0113] Samples of the double-layer anisotropic conductive film (size: 2.0 mm × 20 mm) were cured at a temperature of 200 °C for 10 minutes, and the glass transition temperature (°C) was measured by dynamic viscoelasticity measurement (DMA: Dynamic Mechanical Analysis) at a heating rate of 10 °C / minute.

[0114] [Fabrication of the connection structure]

[0115] The IC chip has an outer shape (X) of 29.8 mm, an outer shape (Y) of 0.84 mm, and a thickness of 0.15 mm. The output-side bumps have a width of 18 μm, a length of 100 μm, a pitch of 18 μm, and the number of bumps is 1424. The input-side bumps have a width of 34 / 24 μm, a length of 100 μm, a pitch of 10 / 8 μm, and the number of bumps is 823. A bump height of 9 μm was used.

[0116] The glass substrate has an outer shape (X) of 60 mm, an outer shape (Y) of 80 mm, and a thickness of 0.3 mm. The film structure of the electrode is a-ITO / Mo / Al, and a measurement TEG with conductive measurement wirings formed on the output side with 30 channels and the input side with 11 channels was used.

[0117] Using a double-layer anisotropic conductive film, the IC chip was thermocompression bonded to the glass substrate to fabricate the first connection structure. In addition, using a single-layer anisotropic conductive film, the IC chip was thermocompression bonded to the glass substrate to fabricate the second connection structure. The thermocompression bonding conditions were set to a temperature of 145 °C, a pressure of 60 MPa, and 5 seconds.

[0118] [Evaluation of connection reliability]

[0119] (Measurement of conduction resistance)

[0120] For the conduction resistance values of the first connection structure samples and the second connection structure samples before and after HAST (High Accelerated Stress Test), a digital multimeter was used to measure with a 4-terminal method by passing 1 mA. The HAST test was set to conditions of a temperature of 110 °C, a humidity of 85%, and a time of 12 hours.

[0121] (Evaluation index)

[0122] Based on whether non-conducting channels and component peeling occurred from before to after HAST, the evaluation was carried out using the following indices.

[0123] A: Neither non-conducting channels nor component peeling occurred;

[0124] B: Either non-conducting channels or component peeling occurred;

[0125] C: Generate both non-conductive channels and component peeling.

[0126] [Measurement of Chip Shear Strength]

[0127] After heating the first connection structure sample on a stage at a temperature of 250 °C for 20 seconds, the IC chip was peeled off using a chip shear tester, and the chip shear strength (kgf) was measured.

[0128] [Evaluation of Reparability]

[0129] The glass substrates after peeling the IC chips of the first connection structure sample and the second connection structure sample were heated on a hot plate at a temperature of 85 °C, and at the same time, methyl ethyl ketone (MEK) was continuously dropped onto the remaining part of the anisotropic conductive film for 1 minute without drying it. The remaining part of the anisotropic conductive film after MEK impregnation was scraped off with a wood bar, and the time until it disappeared was measured.

[0130] (Evaluation Index)

[0131] Based on the time from the start of cutting with a wood bar until the remaining part of the anisotropic conductive film disappears, the evaluation is carried out using the following index.

[0132] A: Less than 20 seconds;

[0133] B: 20 seconds or more and less than 60 seconds;

[0134] C: 60 seconds or more.

[0135] Table 1 shows the glass transition temperatures, evaluation results of connection reliability, chip shear strengths, and evaluation results of reparability of the examples and comparative examples.

[0136] [Table 1]

[0137]

[0138] As shown in Table 1, the evaluation results of the connection reliability and reparability of the first connection structure using a double-layer type anisotropic conductive film and the second connection structure using a single-layer type anisotropic conductive film are the same.

[0139] In Comparative Example 1, since the caprolactone derivative was not blended, good reparability was not obtained. In Examples 1 to 13, since 5 to 40 parts by mass of the caprolactone derivative was blended with respect to the total amount of 100 parts by mass of the ionic polymerizable compound and the caprolactone derivative, excellent connection reliability and reparability were obtained. In particular, in Examples 1, 2, 4, 5, 7, 8, 10, 11, and 12, since 5 to 25 parts by mass of the caprolactone derivative was blended with respect to the total amount of 100 parts by mass of the ionic polymerizable compound and the caprolactone derivative, the reparability was improved while maintaining a high glass transition temperature.

[0140] Figure 3 It is a chart showing the glass transition temperature (Tg) with respect to the content of the caprolactone derivative. Figure 3 The chart shown represents the glass transition temperature with respect to the addition amounts of polycaprolactone diol having a molecular weight of 500, polycaprolactone diol having a molecular weight of 2000, polycaprolactone triol having a molecular weight of 500, and polycaprolactone triol having a molecular weight of 2000. From Figure 3 the chart shown, it can be seen that the change in the glass transition temperature with respect to the content of the caprolactone derivative is larger for bifunctional than for trifunctional. It can also be seen that the change in the glass transition temperature with respect to the content of the caprolactone derivative is larger for low molecular weight than for high molecular weight. It is considered that the effect of lowering the glass transition temperature is higher by incorporating a larger amount of the low molecular weight caprolactone derivative into the crosslinked structure than by lowering the crosslink density with long molecular chains.

[0141] Explanation of reference numerals

[0142] 10 First electronic component, 11 First terminal row, 20 Second electronic component, 21 Second terminal row, 30 Anisotropic conductive adhesive, 31 Conductive particles, 40 Crimping tool.

Claims

1. A connecting material, comprising: an ionic polymerizable compound, an ionic polymerization initiator, and a caprolactone derivative, wherein the content of the caprolactone derivative is 5 to 40 parts by mass relative to the total amount of 100 parts by mass of the ionic polymerizable compound and the caprolactone derivative.

2. The connecting material according to claim 1, wherein, the content of the caprolactone derivative is 5 to 25 parts by mass relative to the total amount of 100 parts by mass of the ionic polymerizable compound and the caprolactone derivative.

3. The connecting material according to claim 1, wherein, the glass transition temperature of the cured connecting material is 170 to 195 °C.

4. The connecting material according to claim 1, further comprising a thermoplastic resin and an insulating filler, wherein the total content of the ionic polymerizable compound and the caprolactone derivative is 10 to 50 wt%.

5. The connecting material according to claim 1, wherein, the ionic polymerizable compound includes an epoxy compound or an oxetane compound, and the ionic polymerization initiator is a cationic polymerization initiator.

6. The connecting material according to claim 1, wherein, the molecular weight per functional group equivalent of the caprolactone derivative is 100 to 3000.

7. The connecting material according to claim 1, wherein, the molecular weight per functional group equivalent of the caprolactone derivative is 100 to 1000.

8. The connecting material according to claim 1, wherein, the caprolactone derivative is one or more selected from polycaprolactone diol, polycaprolactone triol, and polycaprolactone tetraol.

9. The connecting material according to claim 1, further comprising conductive particles.

10. A connecting structure, comprising: a first electronic component, a second electronic component, and an adhesive cured film that bonds the first electronic component and the second electronic component, wherein the adhesive cured film is formed by curing a connecting material, the connecting material comprising: an ionic polymerizable compound, an ionic polymerization initiator, and a caprolactone derivative, and the content of the caprolactone derivative is 5 to 40 parts by mass relative to the total amount of 100 parts by mass of the ionic polymerizable compound and the caprolactone derivative.

11. The connecting structure according to claim 10, wherein, the connecting material further comprises conductive particles.

12. A method for manufacturing a connecting structure, comprising: a disposing step of disposing a first electronic component and a second electronic component with a connecting material therebetween, the connecting material comprising: an ionic polymerizable compound, an ionic polymerization initiator, and a caprolactone derivative, and the content of the caprolactone derivative is 5 to 40 parts by mass relative to the total amount of 100 parts by mass of the ionic polymerizable compound and the caprolactone derivative; and a curing step of pressing the second electronic component onto the first electronic component using a pressing tool while curing the connecting material.

13. The method for manufacturing a connecting structure according to claim 12, wherein, the connecting material further comprises conductive particles.

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