JP2018104653A - Adhesive composition selection method, circuit member connection method, connection structure, adhesive composition, and film-shaped adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of selecting an adhesive composition having excellent connectability and connection reliability at low temperatures.SOLUTION: A method of selecting an adhesive composition includes making a determination that, when an adhesive composition is measured by differential scan calorimetry, the adhesive composition is good in which a reaction initiation temperature is 60°C or above, an exothermic peak temperature is 105°C or below, and a difference between an exothermic peak temperature and an onset temperature is within 15°C.SELECTED DRAWING: None

Description

  The present invention relates to a method for selecting an adhesive composition, a method for connecting circuit members, a connection structure, an adhesive composition, and a film adhesive.

  In recent years, various adhesives have been used in the fields of semiconductors, liquid crystal displays and the like to fix electronic components or connect circuits.

  For example, as a circuit connection material, a connection between a liquid crystal display and a tape carrier package (Tape Carrier Package: TCP), a connection between a flexible printed circuit (Flexible Printed Circuits: FPC) and a TCP, a connection between an FPC and a printed wiring board, etc. , An anisotropic conductive adhesive containing conductive particles is used (see, for example, Patent Document 1). Even when a semiconductor element such as a semiconductor silicon chip is mounted on a substrate, so-called chip-on-glass (COG) is performed in which the semiconductor element is directly mounted on the substrate instead of a conventional wire bond. Also here, anisotropic conductive adhesive is applied.

JP-A-1-251787

  In the fields of semiconductors, liquid crystal displays, etc., higher density and higher definition are progressing. Further, in the field of precision electronic equipment, the density of circuits is increasing, and the electrode width and electrode interval are extremely narrow. For this reason, the adhesive agent which is excellent in connection reliability is calculated | required.

  By the way, for example, when COG is performed under the connection conditions of a conventional adhesive, there is a problem that warpage due to a difference in thermal expansion between the semiconductor element and the substrate occurs. Further, it is necessary to improve the throughput in order to reduce the cost. Therefore, there is a demand for an adhesive that can be connected at a low temperature (for example, 120 to 170 ° C.) and in a short time (for example, within 10 seconds).

  This invention is made | formed in view of the said situation, and it aims at providing the selection method of the adhesive composition excellent in the connectivity and connection reliability in low temperature. Another object of the present invention is to provide a circuit member connection method and a connection structure using the adhesive composition according to the screening method. Another object of the present invention is to provide an adhesive composition and a film-like adhesive that are excellent in low-temperature connectivity and connection reliability.

  When measured by differential scanning calorimetry, the inventors measured the reaction start temperature, the exothermic peak temperature, and the adhesive composition having a difference between the exothermic peak temperature and the onset temperature within a predetermined range at a low temperature. The present invention was completed by discovering excellent connectivity and connection reliability.

  The present invention is a method for selecting an adhesive composition, and when the adhesive composition is measured by differential scanning calorimetry, the reaction start temperature is 60 ° C or higher, and the exothermic peak temperature is 105 ° C or lower. The present invention also relates to a method for selecting an adhesive composition, in which an adhesive composition having a difference between an exothermic peak temperature and an onset temperature of 15 ° C. or less is judged as good.

  The present invention provides a first circuit member having a first connection terminal and a second circuit member having a second connection terminal, wherein the first connection terminal and the second connection terminal are opposed to each other. Between the first connection terminal and the second connection terminal, which are disposed opposite to each other, with an adhesive composition determined to be good in the selection method of the adhesive composition interposed therebetween, and heated and heated. The present invention relates to a circuit member connection method in which the first connection terminal and the second connection terminal are electrically connected to each other.

  The present invention provides a first circuit member having a first connection terminal, a second circuit member having a second connection terminal arranged to face the first connection terminal, and the first circuit. A circuit connection member disposed between the member and the second circuit member and electrically connecting the first connection terminal and the second connection terminal, wherein the circuit connection member is bonded The present invention relates to a connection structure including an adhesive composition that is determined to be good in the method for selecting an adhesive composition or a cured product of the adhesive composition.

  In the present invention, when measured by differential scanning calorimetry, the reaction start temperature is 60 ° C. or higher, the exothermic peak temperature is 105 ° C. or lower, and the difference between the exothermic peak temperature and the onset temperature is within 15 ° C. The present invention relates to an adhesive composition.

  The adhesive composition may contain at least one selected from the group consisting of an epoxy compound and an oxetane compound.

  The present invention relates to a film adhesive comprising the above adhesive composition.

  The film adhesive may include a conductive adhesive region containing conductive particles and an insulating adhesive region.

  ADVANTAGE OF THE INVENTION According to this invention, the selection method of the adhesive composition which is excellent in the low temperature connectivity and connection reliability can be provided. According to the present invention, it is also possible to provide a circuit member connection method and a connection structure using the adhesive composition according to the screening method. According to the present invention, it is also possible to provide an adhesive composition and a film-like adhesive that are excellent in low-temperature connectivity and connection reliability.

It is a figure for demonstrating reaction start temperature, exothermic peak temperature, and onset temperature. It is a schematic diagram which shows the example of the chart obtained by differential scanning calorimetry. It is a schematic cross section which shows one Embodiment of the film adhesive of this invention. It is a schematic cross section explaining one embodiment of a circuit member connection method of the present invention. It is a schematic cross section which shows one Embodiment of the connection structure of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

  In this specification, “(meth) acrylic acid” means at least one of acrylic acid and methacrylic acid corresponding thereto. The materials exemplified below may be used alone or in combination of two or more unless otherwise specified. The content of each component in the composition means the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition. The numerical range indicated by using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively. “A or B” only needs to include either A or B, and may include both.

<Adhesive Composition Selection Method and Adhesive Composition>
The method for selecting the adhesive composition of the present embodiment is such that when the adhesive composition is measured by differential scanning calorimetry (DSC), the reaction start temperature is 60 ° C. or higher and the exothermic peak temperature is 105 ° C. or lower. In addition, the adhesive composition in which the difference between the exothermic peak temperature and the onset temperature is 15 ° C. or less is judged as good. According to this method, it is possible to select an adhesive composition that is excellent in low-temperature connectivity and connection reliability. That is, in this method, the adhesive composition determined to be good can maintain excellent connection reliability even when it is mounted at a lower temperature and in a shorter time than before. Moreover, the adhesive composition determined to be good in the above method is excellent in adhesiveness and storage stability, and it is easy to reduce dropout, peeling, misalignment, etc. of wiring when used for circuit connection.

  Since the adhesive composition is excellent in connectivity at low temperatures, it is easy to improve throughput and reduce costs. For example, when connecting a semiconductor element and a substrate such as a glass substrate, a semiconductor Warpage caused by a difference in thermal expansion between the element and the substrate can be reduced.

  The adhesive composition is, for example, less susceptible to conduction failure or peeling between bonded circuit members even in a moisture resistance test after bonding circuit members, and has excellent connection reliability. Even when used in a field or the like, it is considered that the display screen disturbance due to the above problems and peeling can be reduced.

  Since the adhesive composition is also excellent in storage stability, it is considered that the adhesive composition is unlikely to be restricted by a manufacturing method, a use environment, a use period, and the like.

  Here, the present inventors speculate as follows why the adhesive composition determined to be good in the above method is excellent in low-temperature connectivity, connection reliability, and storage stability.

  When the reaction start temperature of the adhesive composition is high and the exothermic peak temperature is high, it is considered that the reaction is difficult to proceed by mounting at a low temperature. Further, along with this, it is considered that the uncured rate of the adhesive composition tends to be high and the elastic modulus of the cured product tends to be low. Therefore, when such an adhesive composition is used for circuit connection, it is considered that the electrodes facing each other hardly hold the flatness of the conductive particles, and the connection reliability is likely to be lowered. Moreover, when reaction start temperature of an adhesive composition is low, it is thought that storage stability will fall easily. Specifically, when the reaction start temperature of the adhesive composition is low, a part of the adhesive composition is easily cured when left at a constant temperature, so that the fluidity of the adhesive composition is likely to be lowered during mounting. it is conceivable that. As a result, the flatness of the particles becomes insufficient, the electrical conductivity between the opposing electrodes tends to decrease, the adhesion to the substrate decreases, and problems such as poor adhesion are likely to occur. By doing so, it is considered that the storage stability is lowered. On the other hand, when the difference between the reaction start temperature, the exothermic peak temperature and the exothermic peak temperature and the onset temperature is within the specific range, connectivity at low temperatures and connection reliability are excellent, It is thought that storage stability improves.

  The reaction start temperature may be, for example, 100 ° C. or lower, 90 ° C. or lower, or 80 ° C. or lower. The reaction start temperature may be, for example, 65 ° C. or higher, or 70 ° C. or higher. The exothermic peak temperature may be, for example, 70 ° C. or higher, 80 ° C. or higher, or 90 ° C. or higher. The exothermic peak temperature may be, for example, 100 ° C. or lower, or 95 ° C. or lower. The difference between the exothermic peak temperature and the onset temperature may be, for example, 5 ° C or higher, 7 ° C or higher, or 10 ° C or higher. The difference between the exothermic peak temperature and the onset temperature may be, for example, within 10 ° C or within 5 ° C.

  Hereinafter, the reaction start temperature, the exothermic peak temperature, and the onset temperature will be described with reference to FIG. FIG. 1 is a chart showing measurement results by differential scanning calorimetry, with the horizontal axis representing temperature (° C.) and the vertical axis representing heat flow (W / g). The reaction start temperature, the exothermic peak temperature, and the onset temperature are determined based on the above chart. In the above chart, the reaction start temperature indicates the temperature at the point where the exothermic peak rises (P1 in FIG. 1). Moreover, exothermic peak temperature shows the temperature of the exothermic peak point (P2 in FIG. 1). The onset temperature is an extension line of the base line (L1 in FIG. 1) passing through the point where the exothermic peak of the DSC chart rises (P1 in FIG. 1) and the exothermic peak from the point where the exothermic peak rises (P1 in FIG. 1). The temperature corresponding to the intersection with the tangent (L2 in FIG. 1) with respect to the inflection point of the DSC curve between the point (P2 in FIG. 1) is shown. Here, the point at which the exothermic peak rises (P1 in FIG. 1) refers to the point at which the DSC curve starts to change in the positive direction with the baseline heat flow set to zero. Further, the exothermic peak point (P2 in FIG. 1) is a point where the heat flow shows the maximum value.

  Here, the differential scanning calorimetry can be performed using, for example, a differential scanning calorimeter (TA Instruments, DSC Q1000). The measurement conditions can be, for example, a condition in which air is introduced at a flow rate of 10 mL / min and maintained at 30 ° C., and then heated to 250 ° C. at 10 ° C./min.

  FIG. 2 is a schematic diagram showing an example of a chart obtained by differential scanning calorimetry. In FIG. 2, Schematic Example 1 is a chart showing an example in which the reaction start temperature is 60 ° C. or higher, the exothermic peak temperature is 105 ° C. or lower, and the difference between the exothermic peak temperature and the onset temperature is within 15 ° C. It is. The adhesive composition showing such a curve has excellent connection reliability and storage stability. Schematic example 2 is a chart showing an example in which the difference between the exothermic peak temperature and the onset temperature is within 15 ° C., but the exothermic start temperature is less than 60 ° C. The adhesive composition showing such a curve is considered to have lower connection reliability and storage stability than the adhesive composition of the present embodiment. Schematic example 3 is a chart showing an example in which the exothermic peak temperature exceeds 105 ° C. The adhesive composition showing such a curve is considered to have lower connection reliability in mounting at a low temperature in a short time than the adhesive composition of the present embodiment. Schematic example 4 is a chart showing an example in which the difference between the exothermic peak temperature and the onset temperature exceeds 15 ° C. The adhesive composition showing such a curve is considered that the adhesive composition is not sufficiently cured by mounting at a low temperature in a short time, and is inferior in connection reliability as compared with the adhesive composition of the present embodiment. it is conceivable that.

  Next, an adhesive composition that is determined to be good in the method for selecting an adhesive composition of the present embodiment will be described.

  The adhesive composition of this embodiment has a reaction start temperature of 60 ° C. or higher, an exothermic peak temperature of 105 ° C. or lower, and an exothermic peak temperature and an onset temperature, as measured by differential scanning calorimetry. The difference is within 15 ° C. Such an adhesive composition is excellent in low temperature connectivity and connection reliability. The adhesive composition is also excellent in storage stability. The adhesive composition may have, for example, anisotropic conductivity. The adhesive composition is, for example, an adhesive for circuit connection.

  There is no restriction | limiting in particular in the structural component and this content of the said adhesive composition, It can determine suitably that the measured value of DSC in the said adhesive composition becomes in the said range. From the viewpoint of imparting cationic polymerizability to the adhesive composition, the adhesive composition may include, for example, at least one selected from the group consisting of an epoxy compound and an oxetane compound. From the viewpoint of imparting radical polymerizability to the adhesive composition, the adhesive composition may contain, for example, at least one selected from the group consisting of acrylic compounds and styrene compounds. Hereinafter, components and the like that can be contained in the adhesive composition will be described in more detail.

  The adhesive composition of this embodiment may contain an adhesive component and conductive particles, for example. Hereinafter, each component will be described in detail.

[Adhesive component]
The adhesive component includes, for example, (a) a film-forming material (hereinafter sometimes referred to as “(a) component”), (b) a reactive component (hereinafter sometimes referred to as “(b) component”) and (c). A polymerization initiator (hereinafter sometimes referred to as “component (c)”) may be included.

((A) component)
The film-forming material as component (a) is a polymer having an action of solidifying a liquid composition. When the adhesive component contains the component (a), for example, when the adhesive composition is solidified into a film to form a film adhesive (adhesive film), the handleability of the film is improved and it is difficult to tear. Properties such as being hard to break and stickiness can be imparted to the film.

  Examples of the component (a) include phenoxy resin, polyvinyl formal, polystyrene, polyvinyl acetal, polyester, polyamide, xylene resin, and polyurethane. Among these, from the viewpoint of excellent compatibility with the component (b) and from the viewpoint of imparting excellent adhesiveness, heat resistance and mechanical strength to the cured adhesive composition, phenoxy resin, polyurethane and polyvinyl acetal are preferable. (A) A component may be used individually by 1 type and may be used in combination of 2 or more type.

  Examples of the phenoxy resin include a resin obtained by reacting a bifunctional phenol and epihalohydrin until they are polymerized, and a resin obtained by polyaddition reaction of a bifunctional epoxy resin and a bifunctional phenol. Is mentioned. For example, the phenoxy resin contains 1 mol of a bifunctional phenol and 0.985 to 1.015 mol of an epihalohydrin in a non-reactive solvent at a temperature of 40 to 120 ° C. in the presence of a catalyst such as an alkali metal hydroxide. It can be obtained by reacting.

  As the phenoxy resin, from the viewpoint of improving the mechanical properties and thermal properties of the cured adhesive composition, for example, the mixing equivalent ratio of the bifunctional epoxy resin and the bifunctional phenols is changed to an epoxy group / phenolic hydroxyl group. A resin obtained by polyaddition reaction at 1 / 0.9 to 1 / 1.1 is preferable. The resin is, for example, an organic solvent (amide, ether, ketone, lactone, alcohol, etc.) having a boiling point of 120 ° C. or higher in the presence of a catalyst such as an alkali metal compound, an organic phosphorus compound, or a cyclic amine compound. ), The raw material solid content is preferably obtained by heating to 50 to 200 ° C. under a condition of 50% by mass or less to cause a polyaddition reaction.

  Examples of the bifunctional epoxy resin used to obtain the phenoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin, biphenyl diglycidyl ether, and methyl-substituted biphenyl diester. A glycidyl ether is mentioned. Bifunctional phenols are compounds having two phenolic hydroxyl groups. Examples of the bifunctional phenols include hydroquinones, bisphenol A, bisphenol F, bisphenol AD, bisphenol S, bisphenol fluorene, methyl substituted bisphenol fluorene, dihydroxy biphenyl, methyl substituted dihydroxy biphenyl and the like.

  The phenoxy resin may be modified with a radical polymerizable functional group or other reactive compound. A phenoxy resin may be used individually by 1 type, and may be used in combination of 2 or more type.

  Polyurethane is a polymer having a urethane bond in the molecular chain. Polyurethane is an elastomer, for example. From the viewpoint of easy dissolution in an organic solvent, polyurethane is obtained by, for example, subjecting a polybasic acid and a dihydric alcohol to a condensation reaction to obtain a saturated polyester having a hydroxy group at the terminal, and then diisocyanate to the saturated polyester. It may be a linear polymer obtained by reacting a compound. Examples of the polybasic acid include terephthalic acid, isophthalic acid, phthalic acid, succinic acid, adipic acid, azelaic acid, and sebacic acid. Examples of the dihydric alcohol include ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, polyethylene glycol, and propylene glycol. Examples of the diisocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, and cyclohexylmethane diisocyanate. In the above reaction, the amount of the diisocyanate compound used may be, for example, an equivalent amount of the terminal hydroxy group of the saturated polyester and the isocyanate group of the diisocyanate compound.

  Examples of the organic solvent that easily dissolves the polyurethane include, for example, ester compounds such as ethyl acetate and butyl acetate; ketone compounds such as methyl ethyl ketone, cyclohexanone and acetone; aromatic compounds such as toluene, xylene and benzene; and trichloroethylene (trichlene), Examples include chlorine compounds such as methylene chloride.

  Polyvinyl acetal is a polymer having a vinyl acetal unit in the molecular chain. For example, the polyvinyl acetal may be an elastomer. Polyvinyl acetal can be synthesized, for example, by polymerizing vinyl acetate and carrying out an alkali treatment, and further reacting with an aldehyde (methanal, etanal, propanal, butanal, etc.). The polyvinyl acetal may be a linear polymer, for example. Specific examples of polyvinyl acetal include polyvinyl butyral.

  For example, the degree of polymerization of the polyvinyl acetal may be 700 or more from the viewpoint of excellent cohesive force and film formability. The degree of polymerization of the polyvinyl acetal may be, for example, 2500 or less from the viewpoint of excellent fluidity during pressure bonding of the adhesive composition and further improving connection reliability. From these viewpoints, the degree of polymerization of polyvinyl acetal may be, for example, 700 to 2500. The degree of acetalization of polyvinyl acetal may be, for example, 65 mol% or more from the viewpoint of further improving connection reliability. It is considered that the connection reliability is likely to increase as the proportion of the hydroxyl group or acetyl group in the polyvinyl acetal decreases.

  The glass transition temperature (hereinafter referred to as “Tg”) of the component (a) is not particularly limited, but is easily elastically deformed, and is excellent in absorbing internal stress even after curing. From the viewpoint of easily reducing the amount and further improving the connection reliability, for example, it may be 40 to 170 ° C, 45 to 150 ° C, or 50 to 85 ° C.

  From the viewpoint of further suppressing the deformation (warpage amount) of the substrate (base material) and further improving the electrical connection reliability, the content of the component (a) is, for example, with respect to 100 parts by mass of the total mass of the adhesive composition. 1-60 mass parts may be sufficient, 15-50 mass parts may be sufficient, and 20-40 mass parts may be sufficient.

  The weight average molecular weight (Mw) of the component (a) is, for example, 5000 or more from the viewpoint that film formability is easily obtained and the melt viscosity that affects the fluidity of the adhesive composition is easily set over a wide range. It may be 10,000 or more. The weight average molecular weight of the component (a) may be, for example, 300000 or less, or 200000 or less from the viewpoint that good compatibility with other components is easily obtained. From these viewpoints, the weight average molecular weight of the component (a) may be, for example, 5,000 to 300,000, or 10,000 to 200,000.

  The “weight average molecular weight” refers to a value measured from a gel permeation chromatograph (GPC) using a standard polystyrene calibration curve according to the conditions shown in Table 1 below.

((B) component)
Examples of the reactive component (b) include a cationic polymerizable component and a radical polymerizable component. Examples of the cationic polymerizable component include an epoxy compound and an oxetane compound. Examples of the radical polymerizable component include acrylic compounds and styrene compounds. (B) A component may be used individually by 1 type or in combination of 2 or more types.

  As an epoxy compound, a glycidyl ether compound and an alicyclic epoxy compound are mentioned, for example.

  The epoxy equivalent of the epoxy compound may be, for example, 150 or less. The epoxy equivalent of the epoxy compound can be measured by a method according to JIS K 7236. For example, an epoxy compound having an epoxy equivalent of 150 or less may be synthesized by a known method, or can be obtained as a commercial product.

  Examples of the glycidyl ether compound include a glycidyl ether compound having a naphthalene skeleton.

  An alicyclic epoxy compound is a compound having an epoxy group consisting of two carbon atoms constituting a cyclic hydrocarbon skeleton and an oxygen atom in the molecule, and irradiation with actinic rays in the presence or absence of a curing agent. Or what should just be hardened | cured by heating is sufficient. Among these, those having two or more epoxy groups in one molecule are preferable in that the crosslink density when cured is high. The alicyclic epoxy compound is not particularly limited as long as it is a compound having an alicyclic epoxy group, and known compounds can be used. Examples thereof include a compound having a cyclohexene oxide structure obtained by oxidizing a compound having a cyclohexene structure and a compound having a cyclopentene oxide structure obtained by oxidizing a compound having a cyclopentene structure.

  The oxetane compound may be an oxetane compound having an oxetanyl group in the molecule and can be cured by irradiation with actinic rays or heating in the presence or absence of a curing agent. Among these, a compound having two or more oxetane rings is preferable because the crosslink density when cured is high. Furthermore, an aliphatic or alicyclic compound having 2 to 6 oxetane rings and 1 to 6 hydroxyl groups in the molecule is preferable from the viewpoint of further improving curability.

  Examples of acrylic compounds include methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, 2-hydroxy-1,3-diacrylate. Loxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane, 2,2-bis [4- (acryloxypolyethoxy) phenyl] propane, dicyclopentenyl acrylate, tricyclodecanyl acrylate, tris (Acryloyloxyethyl) isocyanurate and urethane acrylate. These can be used alone or in admixture of two or more.

  Examples of styrene compounds include alkyl styrenes such as styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene, octyl styrene; fluorostyrene, chloro Halogenated styrenes such as styrene, bromostyrene, dibromostyrene, iodostyrene; nitrostyrene; acetylstyrene; and methoxystyrene.

  The content of the component (b) is, for example, from the viewpoint that the fluidity of the adhesive composition is not easily lowered when the connection target member is pressure-bonded, for example, with respect to 100 parts by mass of the total mass of the adhesive composition. It may be 5 parts by mass or more, 10 parts by mass or more, or 20 parts by mass or more. The content of the component (b) may be, for example, 50 parts by mass or less and 45 parts by mass or less with respect to 100 parts by mass of the total mass of the adhesive composition, from the viewpoint that the film formability is not easily lowered. It may be 40 mass parts or less. From these viewpoints, the content of the component (b) may be, for example, 5 to 50 parts by mass or 10 to 45 parts by mass with respect to 100 parts by mass of the total mass of the adhesive composition. It may be 20 to 40 parts by mass.

(Component (c))
The polymerization initiator as the component (c) can be appropriately determined depending on, for example, the type of the component (b). For example, when the component (b) is a cationic polymerizable component, the component (c) can be a cationic polymerization initiator. In addition, when the component (b) is a radical polymerizable component, the component (c) can be a radical polymerization initiator. The component (c) may be a latent curing agent, for example. (C) You may use a component individually or in combination of 2 or more types.

  The cationic polymerization initiator may be, for example, a cationic polymerization type so-called ion polymerizable catalytic curing agent. Examples of the cationic polymerization initiator include onium salts such as sulfonium salts, phosphonium salts, ammonium salts, and iodonium salts. These cationic polymerization initiators are considered preferable because they are easy to obtain fast curing and hardly affected by chemical equivalents.

  Specific examples of the sulfonium salt include a sulfonium borate complex represented by the following formula (1).

In formula (1), R ¹ represents an aralkyl group, R ² represents a lower alkyl group (for example, an alkyl group having 1 to 4 carbon atoms), and R ³ represents a group represented by the following formula (i). X represents a halogen atom. However, when R ² is a methyl group, R ¹ is not a benzyl group.

  In formula (i), n shows the number of 1-3.

Examples of the aralkyl group as R ¹ include a benzyl group, an o-methylbenzyl group, a (1-naphthyl) methyl group, a pyridylmethyl group, and an anthracenylmethyl group. R ¹ may be, for example, a 1-naphthylmethyl group from the viewpoint that a fast curing rate can be easily obtained and the viewpoint that it can be easily obtained.

Examples of the lower alkyl group as R ² include a methyl group, an ethyl group, a propyl group, and a butyl group. R ² may be, for example, a methyl group from the viewpoint of easily obtaining a fast curing rate and the viewpoint of easy acquisition.

Specific examples of R ³ include 4-hydroxyphenyl group, 2-hydroxyphenyl group, 3-hydroxyphenyl group, 2,4-dihydroxyphenyl group, 2,6-dihydroxyphenyl group, 3,5-dihydroxyphenyl group, 2 , 3-dihydroxyphenyl group, 2,4,6-trihydroxyphenyl group, 2,4,5-trihydroxyphenyl group and 2,3,4-trihydroxyphenyl group. R ³ may be, for example, a 4-hydroxyphenyl group from the viewpoint that a fast curing rate is easily obtained and the viewpoint that it is easy to obtain.

  Examples of the halogen atom as X include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. From the viewpoint of improving the reactivity, X may be, for example, a fluorine atom. Since fluorine atoms have high electron withdrawing properties, it is considered that the reactivity is easily improved.

  The sulfonium borate complex represented by the formula (1) can be produced, for example, according to the following reaction formula.

In the above formulas (2) and (3), R ¹ , R ² and R ³ are as defined above.

  Specifically, the sulfonium borate complex represented by the formula (1) can be obtained, for example, by the following method. First, the sulfonium antimonate complex represented by the formula (2) is dissolved in an organic solvent such as ethyl acetate, and an aqueous solution of a sodium borate salt represented by the formula (3) is mixed with the solution in an equimolar amount. The obtained two-layer mixture is stirred at a temperature of 20 to 80 ° C. for 1 to 3 hours, and the sodium borate salt represented by the formula (3) is reacted with the sulfonium antimonate complex represented by the formula (2). Next, the organic solvent layer is separated and dried, and then the organic solvent is removed by evaporation under reduced pressure. Thereby, the sulfonium borate complex represented by Formula (1) can be isolated as an evaporation residue. Although there is no particular limitation on the method for synthesizing the sulfonium antimonate complex represented by the formula (2) and the sodium borate salt represented by the formula (3), for example, JP-A-10-245378 and JP-A-10-310587 It can be synthesized by the method described in the publication.

  The content of the component (c) is, for example, from the viewpoint that a sufficient reaction rate can be easily obtained in the curing reaction and from the viewpoint that a better adhesive strength and connection resistance can be easily obtained. It may be 1 part by mass or more, or 5 parts by mass or more. The content of the component (c) may be, for example, 30 parts by mass or less and 25 parts by mass or less with respect to 100 parts by mass of the component (b) from the viewpoint that the storage stability is not easily lowered. Good. From these viewpoints, the content of the component (c) may be, for example, 1 to 30 parts by mass or 5 to 25 parts by mass with respect to 100 parts by mass of the component (b).

  The adhesive component may further contain additives such as a softener, an anti-aging agent, a flame retardant, a pigment, a thixotropic agent, and a silane coupling agent, depending on the application.

[Conductive particles]
As described above, the adhesive composition may contain conductive particles. The conductive particles are dispersed, for example, in the adhesive composition. When the adhesive composition containing conductive particles is used for circuit connection, the variation of the position and height of the circuit electrode is absorbed by deformation of the conductive particles, and the contact area is increased. Can be obtained. In addition, according to such an adhesive composition, the conductive particles may be able to break through and contact the oxide layer and the passive layer on the surface of the circuit electrode, thereby further stabilizing the electrical connection. It is thought that it can plan.

  Examples of the constituent material of the conductive particles include metal and carbon. Examples of the metal include transition metals such as nickel (Ni) and copper (Cu); noble metals such as gold (Au), silver (Ag) and platinum group metals; and alloys such as solder. The conductive particles may be coated particles in which core particles are coated with the metal or carbon. The outermost layer of the conductive particles preferably contains a noble metal such as Au, Ag, or a platinum group metal, and more preferably contains Au, from the viewpoint that a sufficient pot life can be easily obtained. The conductive particles may have, for example, a transition metal such as Ni as a nucleus and the surface thereof coated with a noble metal such as Au, and the surface of the conductive particle as a nucleus with non-conductive glass, ceramic, plastic, etc. A conductive layer made of metal or the like may be formed by coating or the like. The conductive layer may be a single layer or a plurality of layers, but the outermost layer is preferably a noble metal layer.

  Since coated particles (for example, conductive particles having plastic as a core) or hot-melt metal particles can impart deformability by heating and pressurization, it is possible to eliminate variations in height of circuit electrodes and the like during connection, and circuit electrodes It is easy to increase the contact area with the above, and this is considered to further improve the reliability.

  When the outermost layer of the conductive particles is a noble metal layer, the thickness of the noble metal layer may be, for example, 10 nm or more from the viewpoint of easily reducing the resistance between connected circuits. However, when the noble metal layer is provided on a transition metal such as Ni, the thickness of the noble metal layer is preferably 30 nm or more. For example, when a transition metal such as Ni is exposed in the adhesive film due to the loss of the noble metal layer or the like when the conductive particles are mixed and dispersed, it is considered that free radicals are generated due to the redox action of the transition metal. And it is thought that a free radical may reduce the storage stability of adhesive composition. The upper limit of the thickness of the noble metal layer is not particularly limited, but may be 1 μm or less, for example, from the viewpoint of manufacturing cost.

  The average particle size of the conductive particles needs to be smaller than the minimum interval between adjacent electrodes of the circuit member to be connected, and when there is a variation in the height of the circuit electrode, the variation in the height is less than that. Larger is preferred. The average particle diameter of the conductive particles is, for example, 1 μm or more, or 2 μm or more from the viewpoint that it is easy to cope with variations in the height of the circuit electrodes and the conductivity between the circuit electrodes is difficult to decrease. . The average particle diameter of the conductive particles may be, for example, 10 μm or less, or 5 μm or less from the viewpoint that the insulation between adjacent circuit electrodes is difficult to decrease. From these viewpoints, the average particle diameter of the conductive particles may be, for example, 1 to 10 μm or 2 to 5 μm.

  The “average particle diameter” means a value measured as follows. That is, the primary particles of arbitrarily selected conductive particles were observed with a scanning electron microscope (SEM, manufactured by Hitachi, Ltd., product name: S-800) (magnification: 5000 times), and the maximum and minimum diameters thereof were observed. Measure. The square root of the product of the maximum diameter and the minimum diameter is defined as the primary particle diameter of the particle. Then, the primary particle diameter is measured as described above for 50 arbitrarily selected conductive particles, and the average value is defined as the average particle diameter. In addition, the average particle diameter of insulating particles described later is measured in the same manner.

  From the viewpoint of excellent conductivity, the content of the conductive particles may be, for example, 0.1 parts by mass or more with respect to 100 parts by mass of the total mass of the adhesive composition. The content of the conductive particles may be, for example, 50 parts by mass or less, or 40 parts by mass or less with respect to 100 parts by mass of the total mass of the adhesive composition, from the viewpoint of easily suppressing a short circuit or the like of the adjacent circuit. There may be. From these viewpoints, the content of the conductive particles may be, for example, 0.1 to 50 parts by mass or 0.1 to 40 parts by mass with respect to 100 parts by mass of the total mass of the adhesive composition. May be.

  The said adhesive composition can be used as a film adhesive (adhesive film), for example. Hereinafter, an aspect of the film adhesive will be described.

<Film adhesive>
The film adhesive of this embodiment consists of the said adhesive composition. That is, the film-like adhesive of this embodiment has a reaction start temperature of 60 ° C. or higher, an exothermic peak temperature of 105 ° C. or lower, and an exothermic peak when measured by, for example, differential scanning calorimetry (DSC). The difference between the temperature and the onset temperature is within 15 ° C. Such a film adhesive is excellent in low temperature connectivity and connection reliability. The film adhesive is excellent in storage stability. The film adhesive of this embodiment is an adhesive film for circuit connection, for example.

  The film adhesive may include, for example, a conductive adhesive region containing conductive particles and an insulating adhesive region. Here, the insulating adhesive region is a region not containing conductive particles. When the film adhesive includes a conductive adhesive region and an insulating adhesive region, for example, when connecting opposing electrodes, it becomes easier for the electrodes to capture conductive particles, and connection reliability is further improved. Conceivable.

  FIG. 3 is a schematic cross-sectional view showing an embodiment of the film adhesive of the present invention. The film adhesive 10 shown in FIG. 3 includes a conductive adhesive region 3b containing an adhesive component 4b and conductive particles 5, and an insulating adhesive region 3a containing an adhesive component 4a. 10 in the thickness direction in this order. The adhesive component 4b and the adhesive component 4a are, for example, the above-described adhesive components. The conductive particles 5 are, for example, the above-described conductive particles. Further, the adhesive component 4b and the adhesive component 4a may be the same or different. The conductive adhesive region 3b and the insulating adhesive region 3a may be in the form of a conductive adhesive layer and an insulating adhesive layer, respectively. That is, the film adhesive includes, for example, a conductive adhesive layer containing an adhesive component and conductive particles, and an insulating adhesive layer containing an adhesive component formed on the conductive adhesive layer. You may have.

  In the conductive adhesive region 3b, the content of the component (a) is determined from the viewpoint of further suppressing the deformation (warpage amount) of the substrate (base material) and further improving the electrical connection reliability. For example, 5-50 mass parts may be sufficient with respect to 100 mass parts of total mass of the component to comprise, and 10-40 mass parts may be sufficient.

  In the conductive adhesive region 3b, the content of the component (b) constitutes the conductive adhesive region 3b from the viewpoint that the fluidity of the film adhesive 10 is not easily lowered when the connection target member is pressure-bonded. For example, it may be 5 parts by mass or more, 10 parts by mass or more, or 20 parts by mass or more with respect to 100 parts by mass of the total mass of the components. The content of the component (b) may be, for example, 65 parts by mass or less with respect to 100 parts by mass of the total mass of the components constituting the conductive adhesive region 3b from the viewpoint that the film formability is not easily lowered. 60 parts by mass or less, or 50 parts by mass or less. From these viewpoints, the content of the component (b) may be, for example, 5 to 65 parts by mass with respect to 100 parts by mass of the total mass of the components constituting the conductive adhesive region 3b. A mass part may be sufficient and a 20-50 mass part may be sufficient.

  In the conductive adhesive region 3b, the content of the component (c) is the component (b) from the viewpoint that a sufficient reaction rate can be easily obtained in the curing reaction and that a better adhesive strength and connection resistance can be easily obtained. For example, 1 mass part or more may be sufficient with respect to a mass part, and 5 mass parts or more may be sufficient. The content of the component (c) may be, for example, 30 parts by mass or less and 25 parts by mass or less with respect to 100 parts by mass of the component (b) from the viewpoint that the storage stability is not easily lowered. Good. From these viewpoints, the content of the component (c) may be, for example, 1 to 30 parts by mass or 5 to 25 parts by mass with respect to 100 parts by mass of the component (b).

  From the viewpoint of excellent conductivity, the content of the conductive particles 5 may be, for example, 0.1 parts by mass or more with respect to 100 parts by mass of the total mass of the components constituting the conductive adhesive region 3b. Even if the content of the conductive particles 5 is, for example, 50 parts by mass or less with respect to 100 parts by mass of the total mass of the components constituting the conductive adhesive region 3b from the viewpoint of easily suppressing a short circuit or the like of the adjacent circuit. It may be 40 parts by mass or less. From these viewpoints, the content of the conductive particles 5 may be, for example, 0.1 to 50 parts by mass with respect to 100 parts by mass of the total mass of the components constituting the conductive adhesive region 3b. 1-40 mass parts may be sufficient.

  It is preferable that the adhesive component 4a included in the insulating adhesive region 3a has film-forming properties and can suppress deformation of the circuit member when the circuit member is connected. As described above, the adhesive component 4a may be the same as or different from the adhesive component 4b included in the conductive adhesive region 3b. For example, the type and amount of each component may be adjusted so that the fluidity of the insulating adhesive region 3a is greater than the fluidity of the conductive adhesive region 3b.

  Insulating particles may further be contained in the insulating adhesive region 3a and / or the conductive adhesive region 3b. By containing insulating particles in the insulating adhesive region 3a and / or the conductive adhesive region 3b, internal stress in the cured film adhesive is relieved, and deformation of the substrate such as a circuit member is suppressed. It is easy to form a circuit connection structure that is more excellent in connection reliability. The insulating particles are more preferably contained in the insulating adhesive region 3a.

  Examples of the material constituting the insulating particles include inorganic materials such as silica and alumina; silicone rubber, methyl methacrylate / butadiene / styrene (MBS), acrylic rubber, polymethyl methacrylate, and polybutadiene rubber.

  The insulating particles may be particles containing at least one selected from the group consisting of acrylic resin, polyester, polyurethane, polyvinyl butyral, polyarylate, polystyrene, NBR, SBR, and silicone-modified resin. , Polyester, polyurethane, polyvinyl butyral, polyarylate, polystyrene, NBR, SBR and particles comprising a copolymer containing at least one of the structural units constituting the silicone-modified resin. As the insulating particles, one kind may be used alone, or two or more kinds may be used in combination.

  From the viewpoint of excellent dispersibility in the adhesive composition, the insulating particles may be, for example, organic fine particles having a weight average molecular weight of 1,000,000 or more, or may be organic fine particles having a three-dimensional crosslinked structure. . Here, “having a three-dimensional crosslinked structure” indicates that the polymer chain has a three-dimensional network structure. Insulating particles having such a structure can be obtained, for example, by treating a polymer having a plurality of reactive sites with a crosslinking agent having two or more functional groups capable of binding to the reactive sites. It is preferable that both the organic fine particles having a weight average molecular weight of 1 million or more and the organic fine particles having a three-dimensional crosslinked structure have low solubility in a solvent. When the solubility of the insulating particles in the solvent is low, the dispersibility in the adhesive composition is further improved. From the viewpoint of further improving the dispersibility in the adhesive composition, the insulating particles are formed from an alkyl (meth) acrylate-silicone copolymer, a silicone- (meth) acrylic acid copolymer, or a composite thereof. It is preferable that it is the particle | grains which become. Further, as the insulating particles, for example, insulating particles such as polyamic acid particles and polyimide particles described in JP-A-2008-150573 can be used.

  Furthermore, insulating particles having a core-shell structure as the insulating particles and having different compositions between the core layer and the shell layer (for example, core-shell insulating organic particles) can be used. Examples of the core-shell type insulating organic particles include particles obtained by grafting an acrylic resin with a silicone-acrylic rubber core and particles obtained by grafting an acrylic resin with an acrylic copolymer as a core. Insulating particles include core-shell type silicone fine particles as described in International Publication No. 2009/051067; (meth) acrylic acid alkyl ester-butadiene as described in International Publication No. 2009/020005. Insulating organic particles such as styrene copolymers or composites, (meth) acrylic acid alkyl ester-silicone copolymers or composites, silicone- (meth) acrylic copolymers or composites; JP-A-2002-256037 It is also possible to use core-shell structure polymer particles as described in Japanese Patent Publication No. JP-A-2004-18803 and core-shell structure rubber particles as described in JP-A No. 2004-18803.

  The average particle diameter of the insulating particles may be, for example, 0.01 to 2 μm.

  When insulating particles are included in the conductive adhesive region 3b, the total content of the insulating particles and the conductive particles 5 in the conductive adhesive region 3b is from the viewpoint that the film formability and the adhesion to the electrode are difficult to decrease. For example, 80 mass parts or less may be sufficient with respect to 100 mass parts of total mass of the component which comprises the conductive adhesive area | region 3b, and 50 mass parts or less may be sufficient.

  When insulating particles are included in the insulating adhesive region 3a, the content of the insulating particles in the insulating adhesive region 3a is from the viewpoint that the film formability and the adhesion force of the conductive particles 5 to the electrode are difficult to decrease. For example, 60 mass parts or less may be sufficient with respect to 100 mass parts of total mass of the component which comprises the insulating adhesive area | region 3a, and 40 mass parts or less may be sufficient.

  The thickness of the insulating adhesive region 3a may be, for example, 3 to 20 μm or 4 to 16 μm from the viewpoint of excellent workability and conductive particle capturing properties and further improved connection reliability. Good.

  The thickness of the conductive adhesive region 3b may be, for example, 4 to 12 μm or 5 to 10 μm from the viewpoint of excellent workability and conductive particle capturing properties and further improved connection reliability. Good.

  The thickness of the film adhesive 10 may be, for example, 8 μm or more from the viewpoint of easily filling the space between the adherends and hardly reducing the adhesive force. The thickness of the film-like adhesive 10 may be, for example, 40 μm or less from the viewpoint of easily reducing the resin overflowing and adhering to the peripheral parts during pressure bonding. From these viewpoints, the thickness of the film adhesive 10 may be, for example, 8 to 40 μm.

  The film adhesive 10 includes, for example, a method in which a conductive adhesive layer and an insulating adhesive layer are respectively formed and then laminated, a conductive adhesive layer forming composition, and an insulating adhesive layer forming The composition can be prepared by a method in which these are prepared and sequentially applied. In this case, the conductive adhesive region is a portion formed from the conductive adhesive layer or the conductive adhesive layer forming composition, and the insulating adhesive region is the insulating adhesive layer. Or it is a part formed from the said composition for insulating adhesive bond layer formation.

  The insulating adhesive layer and the conductive adhesive layer include, for example, a composition including the adhesive component 4a for the insulating adhesive layer, and a composition including the adhesive component 4b and the conductive particles 5 for the conductive adhesive layer. Each product is dissolved or dispersed in a solvent such as an organic solvent to liquefy it to prepare a coating solution, and this coating solution is applied onto, for example, a peelable substrate (supporting film) to activate the curing agent. It can be formed by removing the solvent below the temperature.

  As another method of forming the insulating adhesive layer and the conductive adhesive layer, the components of the insulating adhesive layer and the conductive adhesive layer are heated to ensure fluidity, and then a solvent is added. A method of removing the solvent at a temperature lower than the activation temperature of the curing agent by applying as a coating solution onto a peelable substrate is mentioned.

  From the viewpoint of improving the solubility of the adhesive component, the solvent is preferably a mixed solvent of an aromatic hydrocarbon solvent and an oxygen-containing solvent.

  Examples of the peelable substrate include a polymer film. Examples of the polymer constituting the polymer film include polyethylene terephthalate (PET), polypropylene, polyethylene, and polyester. The polymer film as the peelable substrate preferably has heat resistance and solvent resistance. As the peelable substrate, a PET film that has been surface-treated so as to have releasability is particularly suitable.

  The thickness of the peelable substrate may be, for example, 20 μm or more from the viewpoint of handleability during temporary pressure bonding. The thickness of the peelable substrate may be, for example, 75 μm or less from the viewpoint of easily suppressing the occurrence of winding slip between the film adhesive 10 and the peelable substrate. From these viewpoints, the thickness of the peelable substrate may be, for example, 20 to 75 μm.

  The film adhesive of this embodiment is suitable as an anisotropic conductive adhesive for connecting (joining) a relatively hard substrate (glass or the like) and a semiconductor element in, for example, mounting such as COG (Chip On Glass). Can be used. For example, between the circuit members such as the glass substrate and the semiconductor element, the circuit electrodes of the respective circuit members are electrically connected to each other by heating and pressurizing with the film adhesive of the present embodiment interposed. be able to.

  The film adhesive of the present embodiment includes, for example, a first circuit member having a first connection terminal on the main surface of the first circuit board and a second connection on the main surface of the second circuit board. A second circuit member having a terminal and the first and second connection terminals in a state of being opposed to each other, and between the first and second connection terminals. It can be used as an adhesive film for circuit connection for electrical connection.

  Next, a circuit member connection method and a connection structure using the adhesive composition according to the present embodiment will be described.

<Circuit member connection method and connection structure>
In the circuit member connection method of the present embodiment, the first circuit member having the first connection terminal and the second circuit member having the second connection terminal are connected to the first connection terminal and the second connection. Terminals are arranged opposite to each other, and an adhesive composition determined to be good in the method for selecting an adhesive composition is interposed between the first connection terminal and the second connection terminal arranged oppositely, In this method, the first connection terminal and the second connection terminal are electrically connected by heating and pressurization. According to such a method, good connection reliability can be obtained even when mounting at a low temperature in a short time. Further, according to the method, since the connection structure can be formed by heating at a low temperature in a short time, the influence of heating on circuit members such as semiconductor elements can be reduced. For this reason, the long-term reliability of the electrical characteristics between circuit members can be further improved.

  The circuit member connection method of the present embodiment includes, for example, a first circuit member having a first connection terminal on the main surface of the first circuit board, and a second circuit member on the main surface of the second circuit board. A second circuit member having a connection terminal, and a method for selecting the adhesive composition between the first circuit member and the second circuit member in a state where the first connection terminal and the second connection terminal are opposed to each other. A method of electrically connecting the first connection terminal and the second connection terminal by interposing an adhesive composition determined to be good in FIG.

  The circuit member connection method of the present embodiment includes, for example, a first circuit member in which a first connection terminal is formed on the main surface of the first circuit board, and a first circuit member on the main surface of the second circuit board. Adhesive composition determined to be good in the above-described method for selecting an adhesive composition, which is interposed between the second circuit member having the two connection terminals formed therein, and the first circuit member and the second circuit member. Even if the first connection terminal and the second connection terminal are heated and pressed in a state where the first connection terminal and the second connection terminal are arranged to face each other, the first connection terminal and the second connection terminal are electrically connected. Good.

  The connection structure of the present embodiment includes a first circuit member having a first connection terminal, a second circuit member having a second connection terminal arranged to face the first connection terminal, A circuit connection member disposed between the first circuit member and the second circuit member and electrically connecting the first connection terminal and the second connection terminal, wherein the circuit connection member comprises: The adhesive composition determined to be good in the method for selecting an adhesive composition or a cured product of the adhesive composition is included. The connection structure of the present embodiment can be manufactured by, for example, the above-described circuit member connection method. The connection structure of this embodiment is a circuit connection structure, for example. The connection structure according to the present embodiment is, for example, a semiconductor device.

  Since the connection structure of the present embodiment includes an adhesive composition or a cured product of the adhesive composition, in which the circuit connection member (connection portion) is determined to be good in the method for selecting an adhesive composition, It is considered that the decrease in the elastic modulus in the connection structure can be easily suppressed, and the deformation of the circuit member after the high temperature and high humidity test can be suppressed. Further, even when manufactured by mounting at a low temperature, it is considered that the adhesion with the member interface and the connection reliability are excellent. Further, in the connection structure of the present embodiment, the connection resistance of the circuit pattern by the first connection terminal and the second connection terminal can be sufficiently reduced, and this state can be maintained for a long period of time. .

  The connection structure of the present embodiment has a first circuit member having a first connection terminal on the main surface of the first circuit board, and a second connection terminal on the main surface of the second circuit board. The second circuit member is provided between the first circuit member and the second circuit member in a state where the first connection terminal and the second connection terminal are opposed to each other, and the first connection terminal and the second connection member A connection structure (joint) including a circuit connection member (circuit joint member) for electrically connecting the two connection terminals, wherein the circuit connection member is good in the method for selecting the adhesive composition. The connection structure may include an adhesive composition to be determined or a cured product of the adhesive composition, and the first connection terminal and the second connection terminal are electrically connected (joined).

  Hereinafter, as one aspect of the present embodiment, a substrate (second circuit member) in which a wiring pattern (first connection terminal) is formed on the main surface of a glass substrate (first circuit substrate), and an IC chip ( Method for connecting a semiconductor element (second circuit member) having a bump electrode (second connection terminal) formed on a main surface of a second circuit board) and a connection structure (circuit) manufactured by the method The connection structure will be described with reference to the drawings.

  FIG. 4 is a schematic cross-sectional view illustrating an embodiment of the circuit member connection method of the present invention. In the circuit member connection method according to the present embodiment, for example, a semiconductor element in which a wiring pattern 1b is formed on a main surface of a glass substrate 1a and a bump electrode 2b is formed on a main surface of an IC chip 2a. 2 is arranged with the above-mentioned film adhesive 10 interposed between the wiring pattern 1b and the bump electrode 2b so that the wiring pattern 1b and the bump electrode 2b face each other, thereby preparing a laminate. Subsequently, the laminated body is heated and pressed from, for example, the side of the glass substrate 1a where the wiring pattern 1b is not formed and / or the side of the IC chip 2a where the bump electrode 2b is not formed, thereby forming the wiring pattern 1b. Are electrically connected to the bump electrode 2b. Here, the film adhesive 10 is composed of an adhesive composition that is determined to be good in the above-described method for selecting an adhesive composition.

  The wiring pattern 1b is preferably formed from a transparent conductive material. As the transparent conductive material, ITO (indium-tin oxide) is typically used. The bump electrode 2b is formed of, for example, a material having conductivity that can function as an electrode (preferably at least one selected from the group consisting of gold, silver, tin, platinum group metals, and ITO). .

  Circuit members such as glass substrates and semiconductor elements usually have one or a plurality of circuit electrodes (connection terminals). At least a part of the connection terminals provided on the circuit members arranged opposite to each other is arranged opposite to each other, and heated and pressed in a state where a film adhesive is interposed between the connection terminals arranged opposite to each other. A connection structure (circuit connection structure) can be obtained by electrically connecting the connection terminals. Specifically, the circuit terminals arranged opposite to each other are heated and pressurized so that the connection terminals arranged opposite to each other are in contact through the conductive particles, in direct contact, or both in contact and direct contact through the conductive particles. Are electrically connected.

  In the circuit member connection method of the present embodiment, the film adhesive 10 formed on the peelable substrate is heated and pressed in a state where the film adhesive 10 is bonded to the substrate 1 to temporarily press the film adhesive 10. Then, after peeling off the peelable substrate, the semiconductor element 2 is placed while aligning the bump electrodes 2b, whereby the substrate 1, the film adhesive 10 and the semiconductor element 2 are laminated in this order (a pair of layers) After preparing a laminate in which the film adhesive 10 is interposed between the circuit members, the laminate may be heated and pressurized. That is, in the circuit member connection method of the present embodiment, for example, a film adhesive is supplied onto a substrate (wiring circuit board) on which a semiconductor element is to be mounted, the semiconductor element is positioned thereon, and heated. The semiconductor element may be connected to the substrate by pressing.

  The conditions for heating and pressurizing the laminate are such that the film-like adhesive 10 is cured and sufficient adhesive strength is obtained according to the curability of the adhesive components 4a and 4b in the film-like adhesive 10. Can be adjusted as appropriate.

  According to the circuit member connection method shown in FIG. 4, for example, the connection structure 100 shown in FIG. 5 can be manufactured.

  FIG. 5 is a schematic cross-sectional view showing an embodiment of the connection structure of the present invention. The connection structure 100 shown in FIG. 5 is a substrate (first circuit member) in which a wiring pattern (first connection terminal (circuit electrode)) 1b is formed on the main surface of a glass substrate (first circuit substrate) 1a. ) 1, a semiconductor element (second circuit member) 2 having a bump electrode (second connection terminal (circuit electrode)) 2 b formed on the main surface of an IC chip (second circuit board) 2 a, and a substrate 1 and a circuit connecting member (connecting portion) 20 interposed between the semiconductor elements 2. In the connection structure 100, the wiring pattern 1b and the bump electrode 2b are electrically connected via the conductive particles 5 in a state of being opposed to each other. That is, the wiring pattern 1b and the bump electrode 2b are electrically connected when the conductive particles 5 are in direct contact with both the wiring pattern 1b and the bump electrode 2b. The circuit connection member 20 is a cured product of the film adhesive (circuit connection adhesive film) 10. The circuit connection member 20 includes a cured product 6a of the adhesive component 4a and a cured product 6b of the adhesive component 4b.

  In the connection structure 100 described above, the circuit connection member 20 includes the cured product 6a of the adhesive component 4a and the cured product 6b of the adhesive component 4b, but the circuit connection member 20 is formed of the adhesive composition. What is necessary is just to include the adhesive composition determined to be good in the selection method or a cured product of the adhesive composition. Moreover, the wiring pattern 1b and the bump electrode 2b may be electrically connected by, for example, direct contact without passing through the conductive particles 5.

  Hereinafter, the present invention will be described more specifically based on examples. However, the present invention is not limited to these examples.

(1) Preparation of adhesive film for circuit connection In order to produce the adhesive for circuit connection, the following material was prepared.
[(A) Film forming material]
"FX-316" (product name, manufactured by Toto Kasei): Phenoxy resin [(b) reactive component]
"Celoxide CEL2021P" (manufactured by Daicel Corporation, product name, epoxy equivalent 137, hereinafter also referred to as "CEL2021P"): cycloaliphatic epoxy resin "Epolide GT401" (manufactured by Daicel Corporation, product name, epoxy equivalent 220, below) "GT401"): cycloaliphatic epoxy resin "HP-4032D" (manufactured by DIC Corporation, product name, epoxy equivalent 148): naphthalene type epoxy resin "S-500" (manufactured by GINRAY, product name, epoxy Equivalent 105): Cycloaliphatic epoxy resin “YL983U” (Japan Epoxy Resin, product name, epoxy equivalent 190): Bisphenol F type epoxy resin “YL980” (Japan Epoxy Resin, product name, epoxy Equivalent 175): Bisphenol A type epoxy resin "OXT-121" (manufactured by Toagosei Co., Ltd., product name): oxetane resin [(c) polymerization initiator]
・ "SI-60LA" (product name, manufactured by Sanshin Chemical Industry Co., Ltd.)
・ "SI-80" (manufactured by Sanshin Chemical Industry Co., Ltd., product name)
・ "SI-100" (manufactured by Sanshin Chemical Industry Co., Ltd., product name)
"TA-60B (polymerization initiator A)" (manufactured by San Apro Co., Ltd., product name): sulfonium borate complex represented by formula (1) [additive]
・ "SH6040" (product name) manufactured by Toray Dow Corning Co., Ltd .: Silane coupling agent [conductive particles]
・ "Micropearl AU" (product name, manufactured by Sekisui Chemical Co., Ltd.)
[Insulating particles]
"X-52-7030" (manufactured by Shin-Etsu Silicone, product name): Silicone fine particles

Example 1
<Preparation of conductive adhesive layer>
Phenoxy resin “FX-316” 20 parts by mass, epoxy resin “CEL2021P” 30 parts by mass, polymerization initiator “SI-100” 6 parts by mass, silane coupling agent “SH6040” 2 parts by mass, conductive particles “ 27 parts by mass of “Micropearl AU” and 15 parts by mass of insulating particles “X-52-7030” were mixed to prepare a coating solution for forming a conductive adhesive layer.

  On the surface on which the release treatment of the 50 μm-thick PET film having been subjected to the release treatment (intermediate release treatment) on one side, a coating solution for forming a conductive adhesive layer was applied to the coating device (manufactured by Yasui Seiki Co., Ltd., (Product name: precision coating machine) and then dried with hot air at 70 ° C. for 5 minutes to form a 10 μm thick conductive adhesive layer on the PET film.

<Preparation of insulating adhesive layer (insulating resin layer)>
15 parts by mass of phenoxy resin “FX-316”, 50 parts by mass of epoxy resin “CEL2101P”, 9 parts by mass of polymerization initiator “SI-100”, 3 parts by mass of silane coupling agent “SH6040”, and insulating particles 23 parts by mass of “X-52-7030” was mixed to prepare a coating solution for forming an insulating adhesive layer.

  On the surface on which the release treatment of a 50 μm-thick PET film having been subjected to release treatment (intermediate release treatment) on one side, a coating solution for forming an insulating adhesive layer was applied to a coating device (manufactured by Yasui Seiki Co., Ltd., Product name: precision coating machine) and then dried with hot air at 70 ° C. for 5 minutes to form an insulating adhesive layer having a thickness of 10 μm on the PET film.

<Production of adhesive film for circuit connection>
The conductive adhesive layer and the insulating adhesive layer obtained above are laminated with a roll laminator while being heated at 50 ° C., and an adhesive film for circuit connection comprising a conductive adhesive region and an insulating adhesive region (Thickness: 20 μm) was produced.

(Examples 2-9 and Comparative Examples 1-9)
An adhesive film for circuit connection was produced in the same manner as in Example 1 except that the blending amount of each material was changed to the amounts shown in Tables 2 and 3. In addition, the numerical value of Table 2 and 3 shows a mass part.

(2) Production of circuit connection structure <Preparation of substrate and semiconductor element>
As a substrate, a glass substrate (Corning # 1737, 38 mm × 28 mm, thickness 0.3 mm) having an ITO (Indium Tin Oxide) wiring pattern (pattern width 50 μm, interelectrode space 5 μm) formed on the surface was prepared. As a semiconductor element, an IC chip (outer dimensions 17 mm × 17 mm, thickness 0.3 mm, bump size 50 μm × 50 μm, space between bumps 50 μm, bump height 15 μm) was prepared.

<Connection of substrate and semiconductor element>
Using the adhesive films for circuit connection prepared in the above examples and comparative examples, the semiconductor element and the substrate were connected as shown below. For connection, a thermocompression bonding tool composed of a stage (150 mm × 150 mm) made of a ceramic heater and a tool (3 mm × 20 mm) was used.

First, the PET film on the conductive adhesive region side of the adhesive film for circuit connection (1.5 mm × 20 mm) is peeled off, and the surface on the conductive adhesive region side is applied to a glass substrate at 80 ° C. and 0.98 MPa (10 kgf / cm). It was affixed by heating and pressurizing for 2 seconds under the conditions of ² ). Next, after the PET film on the insulating adhesive region side of the adhesive film for circuit connection is peeled off and the bumps of the semiconductor element and the substrate are aligned, the measured maximum reached temperature of the adhesive film for circuit connection is 130 ° C. The surface on the insulating adhesive region side is heated and pressed from above the semiconductor element under the conditions of an electrode area converted pressure of 70 MPa for 5 seconds or a measured maximum temperature of 120 ° C. and a bump electrode area converted pressure of 70 MPa for 10 seconds. The circuit connection structure was prepared by attaching the semiconductor element to the semiconductor element and performing the main connection between the semiconductor element and the substrate via the circuit connection adhesive film.

(1) Evaluation (measurement with DSC)
The produced adhesive film for circuit connection 10.0 mg ± 0.2 mg was weighed with an electronic balance (MC210S, manufactured by Sartorius) to obtain a measurement material. Using a differential scanning calorimeter (device name: Q1000-0516, manufactured by TA Instruments), measurement is performed in an air stream under a measurement range of 30 ° C. to 250 ° C. and a temperature increase rate of 10 ° C./min. Peak temperature and onset temperature were measured. Table 4 shows the measurement results of the reaction start temperature, exothermic peak temperature and onset temperature, and the difference between the exothermic peak temperature and onset temperature.

(Connection reliability)
The resistance value between the circuit of a glass substrate and the electrode of a semiconductor element was measured using the produced circuit connection structure. For the measurement, a multimeter (device name: MLR21, manufactured by ETAC) was used, and the temperature was 85 ° C., the humidity was 85% RH, and the THT test (Thermal Humidity Test) was performed for 1000 hours. Based on the resistance value after the THT test, the connection reliability was evaluated in two stages of A and B according to the following criteria. Table 4 shows the measurement results of each circuit connection structure.
A: Less than 10Ω B: 10Ω or more

(Storage stability)
The adhesive film for circuit connection used for the production of the circuit connection structure was left in a constant temperature and humidity chamber (device name: IC2405, manufactured by Yamato Scientific Co., Ltd.) at 30 ° C. for 72 hours or 40 ° C. for 12 hours before use. Except for this, a circuit connection structure was fabricated under the same conditions as described above, and the connection reliability was evaluated. Table 5 shows the measurement results of each circuit connection structure.

  From Table 4, it turns out that the adhesive films for circuit connection of Examples 1-9 are excellent in low temperature connectivity and connection reliability. Moreover, from Table 5, it can be seen that the adhesive films for circuit connection of Examples 1 to 9 are excellent in connection reliability, that is, excellent in storage stability even when left in a constant temperature and humidity chamber before use. .

  From the above, it can be seen that according to the present invention, the curing treatment can be carried out sufficiently quickly in a short time at a low temperature, and an adhesive composition having sufficiently stable connection reliability and storage stability can be selected. In addition, according to the present invention, an adhesive composition and a film-like adhesive that can perform a curing process sufficiently quickly in a short time at a low temperature and have sufficiently stable connection reliability and storage stability, and these are used. A circuit member connection method and a connection structure can be provided.

  DESCRIPTION OF SYMBOLS 1 ... Substrate, 1a ... Glass substrate, 1b ... Wiring pattern, 2 ... Semiconductor element, 2a ... IC chip, 2b ... Bump electrode, 3a ... Insulating adhesive region, 3b ... Conductive adhesive region, 4a, 4b ... Adhesion Agent component, 5 ... conductive particles, 6a, 6b ... cured product, 10 ... film adhesive, 100 ... connection structure.

Claims (7)

A method for selecting an adhesive composition comprising:
When the adhesive composition is measured by differential scanning calorimetry, the reaction start temperature is 60 ° C. or higher, the exothermic peak temperature is 105 ° C. or lower, and the difference between the exothermic peak temperature and the onset temperature is within 15 ° C. A method for selecting an adhesive composition, wherein the adhesive composition is determined to be good. A first circuit member having a first connection terminal;
A second circuit member having a second connection terminal;
The first connection terminal and the second connection terminal are arranged to face each other,
Between the first connection terminal and the second connection terminal arranged to face each other, an adhesive composition determined to be good in the method for selecting an adhesive composition according to claim 1 is interposed, heated, and A circuit member connection method in which pressure is applied to electrically connect the first connection terminal and the second connection terminal. A first circuit member having a first connection terminal;
A second circuit member having a second connection terminal disposed opposite to the first connection terminal;
A circuit connection member disposed between the first circuit member and the second circuit member, and electrically connecting the first connection terminal and the second connection terminal;
The connection structure in which the said circuit connection member contains the adhesive composition determined by the selection method of the adhesive composition of Claim 1, or the hardened | cured material of the said adhesive composition.   Adhesive having a reaction start temperature of 60 ° C. or higher, an exothermic peak temperature of 105 ° C. or lower, and a difference between the exothermic peak temperature and the onset temperature within 15 ° C. when measured by differential scanning calorimetry Composition.   The adhesive composition according to claim 4, comprising at least one selected from the group consisting of an epoxy compound and an oxetane compound.   A film adhesive comprising the adhesive composition according to claim 4 or 5.   The film adhesive according to claim 6, comprising a conductive adhesive region containing conductive particles and an insulating adhesive region.

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