JP2014212311A - Anisotropic conductive film and anisotropic conductive connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anisotropic conductive film and an anisotropic conductive connector in which deterioration due to halogen is less likely to occur at an adhesive part.SOLUTION: In an anisotropic conductive film containing conductive particles and a binder resin, the epoxy resin contained in the binder resin has a total concentration of all chlorine atoms and all bromine atoms of 300 mass ppm or less, preferably 50 mass ppm or less, and 0.1-20 mass% of conductive particles are dispersed into the binder resin. Preferably, the epoxy resin can be obtained by performing epoxidation of the carbon-carbon double bond of a material compound (substrate) having the carbon-carbon double bond, by using peroxide as an oxidizer.

Description

  The present invention relates to an anisotropic conductive film and an anisotropic conductive connector.

  Conventionally, when electrically connecting circuit boards or electronic components such as IC chips and circuit boards, anisotropic conductive films in which conductive particles are dispersed in a resin have been used. An anisotropic conductive film is disposed between the electrodes facing each other, and is heated and pressed to adhere the electrodes to each other so as to have conductivity in the pressing direction and can be electrically connected.

  As an example of such an anisotropic conductive film, for example, Patent Document 1 listed below includes a first containing a polymerized photopolymerizable resin, a thermosetting resin, a curing agent for a thermosetting resin, and conductive particles. An anisotropic conductive film is disclosed in which an adhesive film layer and a second adhesive film layer containing a thermosetting resin and a thermosetting resin curing agent are laminated. Patent Document 2 below discloses an anisotropic conductive film in which conductive particles are dispersed in an insulating adhesive containing a silane coupling agent.

JP2013-12498A JP 2012-186448 A

  However, in the above prior art, the epoxy resin used as a resin for dispersing the conductive particles may contain a halogen such as chlorine derived from epichlorohydrin as a raw material, and migration or the like occurs remarkably. There was a problem that the reliability of the anisotropic conductive film could not be secured.

  An object of the present invention is to provide an anisotropic conductive film and an anisotropic conductive connector which are less likely to cause deterioration of an adhesive portion due to halogen.

  In order to achieve the above object, one embodiment of the present invention is an anisotropic conductive film, wherein the total of the total chlorine atom concentration and the total bromine atom concentration is 300 mass ppm or less, preferably 50 mass ppm or less. Conductive particles are dispersed in an amount of 0.1 to 20% by mass in a binder resin containing an epoxy resin. The epoxy resin is preferably a glycidyl ether compound obtained by oxidizing a compound having two or more allyl ether groups.

  Further, the conductive particles are particles made of at least one metal selected from the group consisting of gold, silver, copper, nickel, aluminum, and palladium, or an alloy of the plurality of metals, and gold, palladium, silver on the metal surface. Metal particles plated with either, resin core balls plated with nickel, gold, palladium, or silver on resin balls, carbon or graphite particles, or the surface of these particles coated with an insulating resin thin film Is preferred.

  Another embodiment of the present invention is an anisotropic conductive connector, wherein electronic components are anisotropically conductively connected using the respective anisotropic conductive films.

  ADVANTAGE OF THE INVENTION According to this invention, the deterioration of the adhesion part originating in a halogen can be suppressed in the case of the assembly of a semiconductor element and various electric and electronic components, or adhesion | attachment to a board | substrate.

  Hereinafter, modes for carrying out the present invention (hereinafter referred to as embodiments) will be described.

  In the anisotropic conductive film according to this embodiment, the conductive particles are contained in an amount of 0.1 to 20% by mass in a binder resin including an epoxy resin in which the total concentration of all chlorine atoms and all bromine atoms is 300 ppm by mass or less, preferably Is dispersed in an amount of 0.2 to 10% by mass.

  The total of the total chlorine atom concentration and the total bromine atom concentration is preferably 50 ppm by mass or less, and more preferably 10 ppm by mass or less.

  Here, the epoxy resin can be obtained, for example, by epoxidizing a carbon-carbon double bond of a raw material compound (substrate) having a carbon-carbon double bond using peroxide as an oxidizing agent. According to this method, unlike the conventional epoxy resin production method using epihalohydrin, since a compound having a carbon-chlorine bond is not used as a raw material, the epoxy resin as the binder resin constituting the anisotropic conductive film of the present embodiment is A compound containing a carbon-chlorine bond and a carbon-bromine bond in the molecule is substantially free. Therefore, the excessive purification process of the halogen derived from the epihalohydrin contained in the conventional epoxy resin is unnecessary. In this specification, “substantially free” means that a compound containing a carbon-chlorine bond and a carbon-bromine bond is not used as a raw material used for synthesizing an epoxy resin, that is, such a compound in the epoxy resin. And its reaction product content is zero. Examples of the oxidizing agent include hydrogen peroxide and peracetic acid, but hydrogen peroxide that is inexpensive and easy to handle is more preferable. In particular, it is preferable to use a 10 to 60% by mass aqueous solution of hydrogen peroxide in terms of reactivity and handleability. In this method, since the raw material does not contain chlorine and bromine, an epoxy resin having a low chlorine and bromine content can be obtained. In this specification, “epoxy resin” refers to a binder component of an anisotropic conductive film, that is, a compound having an oxirane ring constituting a cured product, and includes any of a monomer, an oligomer, and a polymer.

Examples of the raw material compound (substrate) having a carbon-carbon double bond include a cycloalkene having 4 to 12 carbons, an unconjugated cycloalkadiene, cycloalkatriene, or cycloalkatetraene having 6 to 12 carbons, or And compounds having an allyl ether group. The allyl ether _groups, refers to a functional group represented by _{CH 2 = CH-CH 2 -O-} .

  Examples of such raw material compounds (substrates) include phenylallyl ethers, cresol monoallyl ethers, cyclohexenes, cyclooctenes, and the like, for example, bisphenol-A diallyl ether, allyl ether compounds of novolac phenolic resins, cyclohexane Dimethanol diallyl ether, trimethylolpropane triallyl ether, pentaerythritol tetraallyl ether, 3,4-epoxycyclohexane-1-carboxylic acid allyl ester, 3,4-cyclohexenylmethyl-3 ′, 4′-cyclohexene carboxylate, etc. Can be illustrated.

Among these, it is preferable to use a compound having two or more allyl ether groups. As an advantage of producing an epoxy resin by using a compound having two or more allyl ethers as raw materials, in addition to the extremely low mixing of chlorine, the viscosity is lower than that in the case of producing an epoxy resin using ordinary epichlorohydrin. Is possible. When producing an epoxy resin using epichlorohydrin, when a hydroxyl group is added to epichlorohydrin as shown below, it is added from the opposite side (normal addition) to the one added from the terminal side (normal addition). Always be a by-product.

This side reaction is particularly noticeable in aliphatic epoxy resins capable of lowering viscosity. In the case of aliphatic epoxy, not only does chlorine remain, but also by-product primary alcohol and raw material hydroxyl group (usually Since the reactivity of (primary alcohol) is almost the same, epichlorohydrin also reacts there, as shown in the following reaction formula, resulting in a problem that the molecular weight increases and the viscosity increases.

When an aromatic compound is used as a raw material, such a problem does not occur so much due to the difference between the phenolic hydroxyl group of the raw material and the alcoholic hydroxyl group of the by-product, but conversely, the epoxy group of the product and the phenol of the raw material There is a problem that the reactive hydroxyl group easily reacts and the side reaction as shown below occurs at a certain ratio, and the viscosity also increases.

On the other hand, when polyvalent allyl ether is used as a raw material and epoxidized with hydrogen peroxide, the hydroxyl group is protected with allyl ether, so the above-mentioned problem does not occur. By-products are allyl ether remaining as follows. In this case, since the viscosity is lower than that of diglycidyl ether itself, it can be said that it is more suitable not only for the problem of chlorine but also for mixing conductive particles such as Ag.

  Examples of the compound having two or more allyl ether groups include compounds represented by the following general formula (1).

｛式中、Ｒ^１及びＲ^２は、各々独立して水素原子、炭素数１〜６のアルキル基又は炭素数４〜６のシクロアルキル基、炭素数６〜１４のアリール基、あるいは、Ｒ^１とＲ^２は一緒になって炭素数３〜１２のシクロアルカンを形成し、Ｒ^３、Ｒ^４、Ｒ^５及びＲ^６は、各々独立して水素原子、炭素数１から１０のアルキル基、炭素数４〜６のシクロアルキル基又は炭素数６〜１４のアリール基であり、ｎは０又は１の整数を表す。｝

{In the formula, R ¹ and R ² are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 4 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, or R ^1. And R ² together form a cycloalkane having 3 to 12 carbon atoms, and R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, carbon A cycloalkyl group having 4 to 6 carbon atoms or an aryl group having 6 to 14 carbon atoms, and n represents an integer of 0 or 1. }

  Specific examples of such compounds include bisphenol-A diallyl ether, bisphenol-F diallyl ether, 2,6,2 ', 6'-tetramethylbisphenol-A diallyl ether, 2,2'-diallyl bisphenol- A diallyl ether, 2,2′-di-t-butylbisphenol-A diallyl ether, 3,3 ′, 5,5′-tetramethylbiphenyl-4,4′-diallyl ether, 2,2′-diisopropylbiphenol diallyl Ether, 4,4′-ethylidene bisphenol diallyl ether, 4,4′-cyclohexylidene bisphenol diallyl ether, 4,4 ′-(1-α-methylbenzylidene) bisphenol diallyl ether, 4,4 ′-(3,3 , 5-Trimethylcyclohexylidene) bispheno Luzia Lil ether, 4,4 '- (1-methyl - benzylidene) bisphenol diallyl ether.

  Specific examples of the biphenyl diallyl ether having an aromatic ring and two allyl ether groups include 2,2'-biphenyl diallyl ether and tetramethylbiphenyl diallyl ether.

  Moreover, the compound which polyallyzed polyphenol like cresol novolak resin and phenol novolak resin can also be used.

  In addition, aliphatic polyallyl ether having two or more allyl ether groups can also be used. Specifically, 1,5-pentanediol diallyl ether, 1,6-hexanediol diallyl ether, 1,9- Nonanediol diallyl ether, 1,10-decanediol diallyl ether, neopentyl glycol diallyl ether, glycerol triallyl ether, trimethylolpropane triallyl ether, pentaerythritol tetraallyl ether and the like can be mentioned.

Specific examples of the alicyclic diolefin having two allyl ether groups include 1,4-cyclohexanedimethanol diallyl ether and tricyclo [5.2.1.0 ^2,6 ] decandimethanol diallyl ether. Can be mentioned.

  An epoxy resin can be produced by oxidizing the raw material compound (substrate) having a carbon-carbon double bond with hydrogen peroxide as an oxidizing agent. The amount of hydrogen peroxide to be used is not particularly limited, but is 0.5 to 10 equivalents, preferably 0.8 to the amount of carbon-carbon double bonds of allyl ether to be epoxidized with hydrogen peroxide. It is selected from the range of 2 equivalents.

  The method for producing an epoxy resin by oxidizing the raw material compound (substrate) having a carbon-carbon double bond with hydrogen peroxide is not particularly limited, but is a method of reacting in the presence of acetonitrile described below. Is preferable because an epoxy resin containing no catalyst residue can be obtained efficiently.

  The concentration of acetonitrile in the reaction system used in the method for producing an epoxy compound according to the present invention is controlled during the reaction so as to be in the range of 0.6 to 5 mol / L. As the reaction proceeds, the concentration of acetonitrile in the reaction system decreases. When the concentration in the reaction system is less than 0.6 mol / L, the yield decreases. On the other hand, when the concentration exceeds 5 mol / L, the epoxidation selectivity of hydrogen peroxide tends to decrease and the cost increases. Absent. Therefore, the initial concentration at the start of the reaction is set in the above concentration range, the concentration during the reaction is monitored, and the concentration is added by adding within the range not exceeding the upper limit before the concentration falls below the lower limit. Control. Preferably, the concentration is in the range of 0.7-2 mol / L. The total amount of acetonitrile used for the reaction is preferably 0.6 to 2 times (molar ratio), and 0.65 to 1.85 times the total amount of hydrogen peroxide used. Is more preferable.

  The amount of acetonitrile charged at the start of the reaction is preferably 1.2 to 5 molar equivalents based on the number of double bonds of the organic compound having a carbon-carbon double bond, and 2 to 4 molar equivalents. More preferred. When the amount is less than 1.2 molar equivalents, the yield decreases. On the other hand, when the amount exceeds 5 molar equivalents, the epoxidation selectivity of hydrogen peroxide tends to decrease and the cost increases. In addition, the preparation amount at the time of the reaction start of acetonitrile must satisfy | fill the 0.6-2 mol / L which is the concentration range in the reaction system in progress of the said reaction. The origin of acetonitrile used in the present invention is not particularly limited, and other than commercially available products, for example, acetonitrile produced as a by-product during production of acrylonitrile by the Sohio method may be used.

  In the method for producing an epoxy compound according to the present invention, the pH of the reaction solution is preferably 9 to 11, more preferably 9.5 to 11, and still more preferably 10 to 11. When the pH is lower than 9, the reaction rate is lowered, and thus the productivity is deteriorated. On the other hand, when the pH is higher than 11, the reaction proceeds rapidly, which is dangerous and the yield is also lowered. When a compound having two carbon-carbon double bonds is used as the organic compound having a carbon-carbon double bond, the yield and selectivity of diepoxide are affected by the pH of the reaction system. Within the range, the yield and selectivity of diepoxide are both high, which is preferable.

  Examples of basic compounds used for pH adjustment in the reaction system include, for example, inorganic basic compounds such as potassium carbonate, potassium hydrogen carbonate, potassium hydroxide, sodium hydroxide, cesium hydroxide, potassium methoxide, potassium ethoxide, Organic basic compounds such as sodium methoxide, sodium ethoxide, and tetramethylammonium hydroxide can be mentioned. Potassium hydroxide and sodium hydroxide are preferable because of their high solubility in water and alcohol and good reactivity. Among these, potassium carbonate, potassium hydrogen carbonate, potassium hydroxide, sodium hydroxide, potassium methoxide, potassium ethoxide, sodium methoxide, and sodium ethoxide are more preferable in terms of easy pH adjustment.

  The aforementioned basic salt compound can be used as an aqueous solution or an alcohol solution. Examples of the alcohol used as the solvent of the alcohol solution include methanol, ethanol, propanol, butanol and the like, and it is preferable to use the same reaction solvent as described later. The solution of the basic salt compound is preferably added so that the pH of the reaction solution does not fall below 9 with the addition of the aqueous hydrogen peroxide solution. At this time, the temperature of the reaction solution is more preferably in the range of 20 to 100 ° C. Is preferably added so as to maintain the range of 25 to 60 ° C.

  In the method for producing the epoxy compound, the reaction temperature is usually in the range of 20 to 100 ° C, preferably in the range of 25 to 60 ° C. The reaction time depends on the reaction temperature and cannot be determined generally, but is usually in the range of 4 to 48 hours, preferably 4.5 to 28 hours.

  After completion of the reaction, the reaction solution is diluted with pure water, or neutralized by adding an acid such as sulfuric acid to the reaction solution as necessary. After dilution with pure water, the solvent is distilled off, and the residue is diluted with ethyl acetate or the like. Extract with an organic solvent. Thus, after concentrating the organic layer isolate | separated from the water layer, the obtained epoxy compound can be taken out by normal methods, such as distillation, chromatographic separation, recrystallization, and sublimation.

  In addition to the epoxy resin, the resin functioning as a binder may include other thermoplastic resins and thermosetting resins. As these resins, for example, by containing a resin that functions as a reactive elastomer, film moldability is improved. Reactivity means having a functional group that reacts with other resin components (including epoxy resins) in the anisotropic conductive film. In addition, the elastic modulus of the cured resin can be lowered to improve the adhesive force, and the residual stress at the time of connection can be reduced. For this reason, connection reliability can be improved.

  The material of the reactive elastomer is not particularly limited, but has a film-forming property such as phenoxy resin, polyester resin, polyurethane resin, polyimide resin, polybutadiene, polypropylene, styrene-butadiene-styrene copolymer, polyacetal. Resin, polyvinyl butyral resin, acrylic rubber, butyl rubber, chloroprene rubber, polyamide resin, acrylonitrile-butadiene copolymer, acrylonitrile-butadiene-methacrylic acid copolymer, acrylonitrile-butadiene-styrene copolymer, polyvinyl acetate resin, nylon, A styrene-isoprene copolymer, a styrene-butylene-styrene block copolymer, or the like can be used, and these can be used alone or in admixture of two or more.

  Although the compounding quantity of a reactive elastomer is not specifically limited, It is preferable that it is 10 to 300 mass parts with respect to 100 mass parts in total with an epoxy resin and a hardening | curing agent. When the blending amount is not more than the upper limit value, the fluidity of the anisotropic conductive film is improved, and the connection reliability is improved. Moreover, wettability with various adherends is improved, and adhesion is improved. Moreover, the film forming property when it is set as an anisotropic conductive film as a compounding quantity is more than a lower limit will improve. Moreover, since the elasticity modulus of hardened | cured material becomes high, there exists a merit that the adhesiveness with respect to various to-be-adhered bodies improves, or the connection reliability after a thermal shock test improves.

  A preferable example of the reactive elastomer is acrylic rubber. Examples of the acrylic rubber include a polymer or copolymer having at least one of acrylic acid, acrylic acid ester, methacrylic acid ester or acrylonitrile as a monomer component, including glycidyl acrylate or glycidyl methacrylate containing a glycidyl ether group. A copolymer acrylic rubber is preferably used.

上記一般式（２）において、Ｒ₁は、水素、メチル基、エチル基、プロピル基、ブチル基のいずれかを示し、Ｒ₂は、水素、メチル基、エチル基、プロピル基、ブチル基のいずれかを示す。また、Ｒ₁とＲ₂とが同じ基であっても異なる基であってもよい。また、上記一般式（２）において、Ｘは４０ｍｏｌ％以上９８．５ｍｏｌ％以下、Ｙは１ｍｏｌ％以上５０ｍｏｌ％以下、Ｚは０．５ｍｏｌ％以上１０ｍｏｌ％以下である。また、上記一般式（２）に示したアクリルゴムの分子量は、たとえば、１００００以上１５０００００以下である。上記一般式（２）に示したアクリルゴムを用いることにより、密着性および接続信頼性をさらに向上させることができる。 Specifically, the acrylic rubber can be, for example, a compound represented by the following general formula (2).

In the general formula (2), R ₁ represents any _one of hydrogen, methyl group, ethyl group, propyl group, and butyl group, and R ₂ represents any one of hydrogen, methyl group, ethyl group, propyl group, and butyl group. Indicate. R ₁ and R ₂ may be the same group or different groups. Moreover, in the said General formula (2), X is 40 mol% or more and 98.5 mol% or less, Y is 1 mol% or more and 50 mol% or less, Z is 0.5 mol% or more and 10 mol% or less. The molecular weight of the acrylic rubber represented by the general formula (2) is, for example, 10,000 or more and 1500,000 or less. By using the acrylic rubber represented by the general formula (2), the adhesion and connection reliability can be further improved.

  The resin functioning as a binder containing these other thermoplastic resins and thermosetting resins preferably has a low chlorine concentration and bromine concentration. The total chlorine atom concentration and the total bromine atom concentration with respect to the total amount of the resin functioning as the binder. Is preferably 300 ppm by mass or less. More preferably, it is 50 mass ppm or less, More preferably, it is 10 mass ppm or less.

  As epoxy resins, bisphenol A type and bisphenol F type epoxy resins are used because excellent adhesiveness and excellent heat resistance can be obtained even if the blending amount of the resin is suppressed to an amount that does not impair the conductivity. preferable. Further, from the same viewpoint, a resol type phenol resin may be mixed.

  From the viewpoint of film formability, it is preferable to use an epoxy resin that is solid at room temperature, but a liquid epoxy resin may be used in combination as long as it does not hinder film formation even if blended.

  Liquid epoxy resins include bisphenol A type epoxy resins having an average molecular weight of about 400 or less; branched polyfunctional bisphenol A type epoxy resins such as p-glycidoxyphenyldimethyltolyl bisphenol A diglycidyl ether; bisphenol F type Epoxy resin; phenol novolac type epoxy resin having an average molecular weight of about 570 or less; 1,5-pentanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,9-nonanediol diglycidyl ether, 1, 10-decanediol diglycidyl ether, neopentyl glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether Any aliphatic polyglycidyl ether; vinyl (3,4-cyclohexene) dioxide, 3,4-epoxycyclohexylcarboxylic acid (3,4-epoxycyclohexyl) methyl, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate ), 2- (3,4-epoxycyclohexyl) 5,1-spiro (3,4-epoxycyclohexyl) -m-dioxane, an alicyclic epoxy resin having as a constituent component is exemplified.

  Examples of the epoxy resin that is solid at room temperature include epoxy resins such as high molecular weight bisphenol A type epoxy resin, diglycidyl biphenyl, and novolac epoxy resin; novolac phenol resin, 3,4-epoxycyclohexane-1-carboxylic acid allyl ester, etc. Examples thereof include a polymer obtained by polymerizing a double bond of a compound having a double bond and an epoxy group, and a copolymer with a compound having another radical double bond.

  Examples of the compound having a radical double bond capable of copolymerization include allyl benzoate, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, and the like. . Here, “(meth) acrylic acid” means acrylic acid and / or methacrylic acid.

  As a curing mechanism of the epoxy resin, a self-curing resin may be used, or a curing agent or a curing accelerator may be used.

  Curing agents usually used for the epoxy resin include acid anhydrides, polyamines, polyphenol compounds and the like.

  As such a curing agent, specifically in the case of an acid anhydride, hexahydrophthalic anhydride, 1,2,3,6-tetrahydrophthalic anhydride, 3,4,5,6-tetrahydrophthalic anhydride, 3-methyl-1,2,3,6-tetrahydrophthalic anhydride, 4-methyl-1,2,3,6-tetrahydrophthalic anhydride, 3-methyl-hexahydrophthalic anhydride, 4-methyl-hexahydrophthalic anhydride Acid, 5-norbornene-2,3-dicarboxylic anhydride, norbornane-2,3-dicarboxylic anhydride, methyl-3,6-endomethylene-1,2,3,6-tetrahydrophthalic anhydride, methyl- In addition to 3,6-endomethylenehexahydrophthalic anhydride and dodecenyl succinic anhydride, alicyclic compounds having conjugated double bonds such as α-terpinene and alloocimene and anhydrous Alicyclic carboxylic acid anhydride-based curing agents such as Diels-Alder reaction products with hydric acid and hydrogenated products, and aromatic anhydrides include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride Benzophenone tetracarboxylic acid anhydride, polyadipic acid anhydride, polyazeline acid anhydride, polysebacic acid anhydride, and the like.

  As polyamines, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenediamine, diethylaminopropylamine, N-aminoethylpiperazine, isophoronediamine, m-xylylenediamine, p-xylylenediamine, hydrogenated as aliphatic amines Examples of the aromatic amine include m-phenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone.

  As the polyphenol compound, a so-called phenol resin such as a phenol novolak resin or a cresol novolak resin, polyvinyl phenol, or the like is used.

  Moreover, in order to accelerate | stimulate reaction of an epoxy resin and a hardening | curing agent, hardening accelerators, such as imidazole and dicyandiamide, can also be used together. Needless to say, it is preferable that the content of chlorine and bromine is low in these curing agents and curing accelerators.

  Further, the conductive particles used in the anisotropic conductive film of the present embodiment are at least one metal selected from the group consisting of gold, silver, copper, nickel, aluminum, palladium, or an alloy of the plurality of metals. Particles, metal particles plated with gold, palladium or silver on the metal surface, resin core balls plated with nickel, gold, palladium or silver on resin balls, carbon or graphite particles, or It is preferable that the surface of these particles is coated with an insulating resin thin film, but is not limited thereto, and can exhibit electrical conductivity and have large adhesion (to the extent that it cannot be used as an adhesive). If not, you can use it. The shape of the conductive particles is not particularly limited, and various shapes such as a spherical shape, a flat plate (flat) shape, and a rod shape can be used, but a spherical shape is preferable. The preferred particle size depends on the distance between adjacent terminals (bumps) and wirings of the electronic component to be connected, but it is 1/2 or less, preferably 1/5 or less, the distance between adjacent terminals (bumps) or wirings. Is 1/10 or less, and those in the range of 5 nm to 20 μm can be used. The particle diameter here is a number-based D50 (median diameter) particle measured by a laser diffraction / scattering method when the particle diameter is 500 nm or more, and by a dynamic light scattering method when it is less than 500 nm. Means diameter.

  The compounding quantity of the electroconductive particle disperse | distributed in the binder resin which comprises an anisotropic conductive film shall be 0.1-20 mass%, Preferably it shall be the range of 0.2-10 mass%. If it is less than 0.1% by mass, the conduction reliability as an anisotropic conductive film is lowered, and if it exceeds 20% by mass, the anisotropic conductivity is lowered.

  The anisotropic conductive film of this embodiment is suitable for adhesion of elements, substrates, etc. by selecting the type and amount of conductive resin and binder resin including the epoxy resin, and using a diluent as necessary. Viscosity can be adjusted.

  In the anisotropic conductive film of this embodiment, in addition to the above, an aluminum chelate compound such as diisopropoxy (ethylacetoacetate) aluminum as a dispersion aid, if necessary, isopropyl triisostearoyl titanate An aliphatic polyvalent carboxylic acid ester; an unsaturated fatty acid amine salt; a surfactant such as sorbitan monooleate; or a polymer compound such as a polyesteramine salt or polyamide may be used. Moreover, you may mix | blend an inorganic and organic pigment, a silane coupling agent, a leveling agent, a thixotropic agent, an antifoamer, etc.

  The anisotropic conductive film can be produced by dispersing conductive particles in the above-described binder resin and forming the obtained dispersion on a release film. In order to disperse the conductive particles in the binder resin, the conductive particles are uniformly mixed and prepared by a mixing means such as a laika machine, a propeller stirrer, a kneader, a roll, and a pot mill. Preparation temperature is not specifically limited, For example, it can prepare at normal temperature.

  The anisotropic conductive film of the present invention is disposed between electrodes to be connected, such as a flexible substrate, a rigid substrate, and an electronic component, in the same manner as a conventional anisotropic conductive film. Irradiation or the like can be performed, and the electrode can be used for an anisotropic conductive connection in which electrodes are electrically and mechanically connected. This makes it possible to manufacture an anisotropic conductive connection body having high connection reliability. Here, the anisotropic conductive connection refers to a connection that is conductive between opposing electrodes (vertical direction) and insulative between adjacent electrodes (horizontal direction).

  Examples of the present invention will be specifically described below. In addition, the following examples are for facilitating understanding of the present invention, and the present invention is not limited to these examples.

The conductive particles used in the examples are the following silver particles.
EHD: Silver particles (spherical) manufactured by Mitsui Mining & Smelting Co., Ltd. D50 = 620 nm
Here, D50 is a number-based median diameter measured by a laser diffraction / scattering method.

Synthesis example 1
Synthesis of 3,4-epoxycyclohexane-1-carboxylic acid allyl ester and production of the polymer Na ₂ WO ₄ · 2H ₂ O (500 mg, 1.5 mmol), 40% by mass hydrogen peroxide aqueous solution (7.65 g, 90 mmol), methyl trioctylammonium hydrogen sulfate (260 mg, 0.56 mmol) and allyl 3-cyclohexene-1-carboxylate (12.5 g, 75 mmol) were mixed and reacted at 25 ° C. for 15 minutes, then 70 ° C. The mixture was heated up to 3.5 hours and stirred for 3.5 hours. After completion of the reaction, it was cooled to room temperature. After post-treatment with a saturated aqueous solution of sodium thiosulfate, the organic layer was taken out. When the obtained solution was measured by gas chromatography, the conversion of allyl 3-cyclohexene-1-carboxylate as a raw material was 79% and 3,4-epoxycyclohexane-1 as a bifunctional epoxy monomer. -It was confirmed that carboxylic acid allyl ester was produced in a yield of 69%. The result was that no diepoxide was produced and the selectivity of monoepoxide was 87.3%.

In addition, the conversion rate and the selectivity were calculated by the following calculation formula based on the result analyzed by gas chromatography.
Conversion rate (%) = (1-Mole number of remaining raw material / Mole number of used raw material) × 100
Selectivity (%) = {(yield (%) / conversion (%)} × 100

  100 g of 3,4-epoxycyclohexane-1-carboxylic acid allyl ester obtained by scaling up in substantially the same manner as above, 80 g of diethylene glycol monomethyl ether acetate, 89 g of benzoic acid allyl ester, t-butylisopropyl peroxycarbonate (Nippon Yushi Co., Ltd., Perbutyl I (containing 75% of the main component)) was charged into a 500 ml separable flask equipped with 4.7 g and a stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen inlet tube, and heated to 110 ° C. Thereafter, the mixture was stirred for 1 hour. t-Butyl isopropyl peroxycarbonate was added in 4.7 g portions every 3 hours, and after completion of addition, the mixture was further aged in a nitrogen atmosphere at 110 ° C. for 2 hours to obtain an epoxy group-containing polymer solution. Obtained. The reaction was carried out under a nitrogen stream.

  During the reaction, the remaining amount of 3,4-epoxycyclohexane-1-carboxylic acid allyl ester and benzoic acid allyl ester was measured by gas chromatography, and the reaction was traced by calculating the conversion rate. The following points were defined as reaction end points. Together with the results of gel permeation chromatograph (hereinafter abbreviated as GPC) at this point, it was confirmed that the polymerization reaction had progressed. The epoxy equivalent of the solid content of the obtained resin was 381 g / eq. (Theoretical epoxy equivalent 344 g / eq.) And the number average molecular weight Mn was 1,315. The total chlorine atom concentration was 6 ppm by mass, and the total bromine atom concentration was less than 1 ppm by mass.

  The epoxy equivalent, number average molecular weight, total chlorine atom concentration and total bromine atom concentration were determined by the following methods, respectively.

<Epoxy equivalent>
The epoxy equivalent was determined according to JIS-K7236. A sample is weighed 0.1 to 0.2 g and placed in an Erlenmeyer flask, and then 10 mL of chloroform is added and dissolved. Next, 20 mL of acetic acid is added, followed by 10 mL of tetraethylammonium bromide solution (100 g of tetraethylammonium bromide dissolved in 400 mL of acetic acid). 4 to 6 drops of crystal violet indicator were added to this solution, titrated with a 0.1 mol / L perchloric acid acetic acid solution, and an epoxy equivalent was determined according to the following formula based on the titration result.
Epoxy equivalent (g / eq) = (1000 × m) / {(V1−V0) × c}
m: weight of the sample (g)
V0: Amount of perchloric acid acetic acid solution consumed for titration to the end point in the blank test (mL)
V1: Amount of perchloric acid acetic acid solution consumed for titration to the end point (mL)
c: Concentration of perchloric acid acetic acid solution (0.1 mol / L)

<Number average molecular weight>
Using gel permeation chromatography (hereinafter abbreviated as GPC), the value was calculated as a value converted to polystyrene (standard sample, STANDARD SM-105 manufactured by Showa Denko KK). The measurement conditions for GPC are as follows.
Device name: HPLC unit HSS-2000 manufactured by JASCO Corporation
Column: Shodex column LF-804
Mobile phase: Tetrahydrofuran Flow rate: 1.0 mL / min Detector: JA-20 Co., Ltd. RI-2031Plus
Temperature: 40.0 ° C
Sample amount: 100 μl of sample loop Sample concentration: prepared at around 0.1% by mass.

<Total chlorine atom concentration and total bromine atom concentration>
Chlorine atom concentration and bromine atom concentration are measured by burning and decomposing epoxy compounds at a high temperature of 800 ° C or higher, absorbing the decomposition gas in ultrapure water, etc., and quantifying chlorine and bromine atoms by ion chromatography. (Pretreatment combustion device AGF-100 (manufactured by Mitsubishi Chemical Analytic Co., Ltd.), gas adsorption device GA-100 (manufactured by Mitsubishi Chemical Analytic Co., Ltd.), ion chromatograph ICS-100 (manufactured by Dionex Corporation)).

Synthesis example 2
Synthesis of bisphenol-A-glycidyl ether In a 2000 ml eggplant-shaped flask, 148.4 g (0.650 mol) of bisphenol-A (manufactured by Mitsui Chemicals), 50% water content 5% -Pd / C-STD type (N. 1.38 g (0.650 mmol), manufactured by Echemcat Co., Ltd., 1.639 g (6.50 mmol) of triphenylphosphine (manufactured by Hokuko Chemical Co., Ltd.), 189 g (1.37 mol) of potassium carbonate (manufactured by Nippon Soda Co., Ltd.), 143 g (1.43 mol) of allyl acetate (manufactured by Showa Denko KK) and 64.1 g of isopropanol were added and reacted at 85 ° C. for 8 hours in a nitrogen atmosphere. After the reaction, a part was sampled, diluted with ethyl acetate, and analyzed by gas chromatography, and it was confirmed that the ratio of bisphenol-A-diallyl ether to monoallyl ether was up to 98: 2.

  Thereafter, 200 g of toluene was added to the reaction solution, Pd / C and the precipitated solid were removed by filtration, and isopropanol and toluene were distilled off by an evaporator. This reaction and post-treatment operation were repeated four times, and then 493 g of a distillate (isolation yield 61.7%, diallyl ether 98.1%, the rest was mono) by using a molecular distillation apparatus (manufactured by Otsuka Kogyo Co., Ltd.). Allyl ether), 245 g of non-distilled product (96.5% diallyl ether).

Bisphenol-A-diallyl ether (50.05 g, 162.3 mmol), acetonitrile (26.63 g, 648.7 mmol), ethanol (265.1 g, 5754.2 mmol) obtained by the above operation were placed in a 1 L 4-diameter eggplant type flask. The sample was weighed (the acetonitrile concentration in the system at this stage was 1.55 mol / L, pH = 8.2). Saturated aqueous potassium hydroxide solution (KOH / H ₂ O = 110 mg / 100 mL) was added so that the pH was not lower than 9. 45% hydrogen peroxide (53.92 g, 713.5 mmol) was added to the 100 mL dropping funnel over 2 hours. (Acetonitrile concentration in the system at this stage: 1.18 mol / L, pH = 9.2). Saturated aqueous potassium hydroxide solution was added dropwise so that the reaction temperature did not exceed 30 ° C., and the pH was allowed to reach 10.5 over 2 hours (2 hours after the end of the hydrogen peroxide solution addition), and the pH was controlled to 10.5. The mixture was further stirred for 2 hours (reducing the acetonitrile concentration in the system to 0.61 mol / L at this stage). Subsequently, acetonitrile (13.31 g, 324.2 mmol) was weighed into a 50 mL dropping funnel and dropped over 2 hours (after addition, acetonitrile concentration 0.91 mol / L). At the same time, 45% hydrogen peroxide (53.92 g, 713.5 mmol) was added dropwise over 4 hours with a 100 mL dropping funnel (the pH was adjusted to 10 to 4 hours so that the reaction temperature did not exceed 30 ° C. The reaction was terminated by stirring for 4 hours while controlling the pH to 10.5 (acetonitrile concentration at the end of the reaction was 0.62 mol / L). The reaction solution was diluted with pure water (100 g), and the solvent was distilled off under reduced pressure. The residue was extracted with ethyl acetate (100 g), pure water (100 g) was added again, and a liquid separation operation was performed. When the obtained solution was measured by gas chromatography, the conversion of the raw material bisphenol A type diallyl ether was 100%, the diepoxy monomer bisphenol A type diglycidyl ether was 87.7%, and monoglycidyl. It was confirmed that the ether was 5.1%.

  Ethyl acetate was distilled off with an evaporator to obtain the desired epoxidation product. The chlorine atom concentration measured in the same manner as in Synthesis Example 1 was 6 ppm by mass, the total bromine atom concentration was less than 1 ppm by mass, and the epoxy equivalent was 178 g / eq. there were.

Synthesis example 3
Polymerization of acrylic rubber 40.0 g of butyl acrylate, 30.0 g of ethyl acrylate, 30.0 g of acrylonitrile, 30.0 g of glycidyl methacrylate, and 260 g of ethyl acetate were charged into a 1000 ml eggplant flask equipped with a mechanical stirrer and a Dimroth condenser, under a nitrogen stream. Then, 0.65 g of azobisisobutyronitrile dissolved in 1.3 g of ethyl acetate was added dropwise at 65 ° C. After 2 hours and 4 hours, a solution of 0.65 g of azobisisobutyronitrile dissolved in 1.3 g of ethyl acetate was added again, and the reaction was carried out over 10 hours. confirmed. The molecular weight of the obtained polymer was 80,000.

Example 1
To 5 g of the epoxy resin of Synthesis Example 1, 54 g of the acrylic rubber of Synthesis Example 3 and 15 g of the epoxy resin of Synthesis Example 2, 10 g of ethyl acetate was added and dissolved. 2 g of a cationic curing agent (sulfonium salt, manufactured by Sanshin Chemical Industry Co., Ltd .: SI-60) was added to this solution to prepare an adhesive solution. 30 g of an ethyl acetate dispersion (10% by mass) of silica filler (Nippon Aerosil Co., Ltd .: Aerosil R805) was added to this adhesive solution and stirred. Furthermore, 20 g of EHD was mixed with the adhesive solution, and ultrasonic dispersion was performed. This dispersion was applied to a silicone-treated polyethylene terephthalate film separator (thickness 40 μm) with a roll coater and dried at 80 ° C. for 5 minutes to produce an anisotropic conductive film having a thickness of 20 μm.

Comparative Example 1
An anisotropic conductive film was prepared in the same manner as in Example 1 except that jER828 (manufactured by Mitsubishi Chemical Corporation, chlorine atom concentration: 1710 ppm, total bromine atom concentration: less than 1 ppm by mass) was used instead of the epoxy resin of Synthesis Example 2. Produced.

  The adhesive part was extracted from the films produced in Example 1 and Comparative Example 1 using methylene chloride as a solvent, and the concentration of chlorine atoms in the solid after evaporation of the solvent and drying to dryness was 2 ppm. On the other hand, 382 ppm of chlorine atoms were detected from the comparative example.

  Next, using the produced anisotropic conductive film, a chip (1.7 × 17 mm, thickness: 0.5 μm) with gold bumps (area: 30 × 90 μm, space: 10 μm, height: 15 μm, bump number: 362) A connection structure sample of a glass substrate with an Al circuit (thickness: 0.7 mm) having a wiring pitch of 40 μm (line / space = 30 μm / 10 μm, line thickness: 10 μm) was produced by the following method.

First, an anisotropic conductive film (2 × 19 mm) was attached to a glass substrate with an Al circuit at 80 ° C. and 0.98 MPa (10 kgf / cm ² ), then the separator was peeled off, and the chip bump and the glass with the Al circuit. The substrate was aligned. Next, the main connection was performed by heating and pressing from above the chip under the conditions of 190 ° C., 40 g / bump, and 10 seconds. As a result of measuring the connection resistance immediately after the preparation of the sample, it was confirmed that anisotropic conductive connection was achieved in both the example and the comparative example. After that, the temperature was 85 ° C., the humidity was 85%, the treatment was performed for 200 hours (HH treatment), and the connection resistance was measured again. As a result, good anisotropic conductive connection was maintained in Example 1, but poor conductive connection occurred in Comparative Example 1. .

Claims (5)

  An anisotropic conductive film in which conductive particles are dispersed in an amount of 0.1 to 20% by mass in a binder resin containing an epoxy resin whose total chlorine atom concentration and total bromine atom concentration are 300 ppm by mass or less.   The anisotropic conductive film according to claim 1, wherein a total of total chlorine atom concentration and total bromine atom concentration of the epoxy resin is 50 mass ppm or less.   The anisotropic conductive film according to claim 1 or 2, wherein the epoxy resin is a glycidyl ether compound obtained by oxidizing a compound having two or more allyl ether groups.   The conductive particles are particles made of at least one metal selected from the group consisting of gold, silver, copper, nickel, aluminum, and palladium or an alloy of the plurality of metals, and any one of gold, palladium, and silver on the metal surface A metal particle plated with resin, a resin core ball plated with nickel, gold, palladium, or silver on a resin ball, carbon or graphite particles, or a surface of these particles coated with an insulating resin thin film. The anisotropic conductive film as described in any one of Claim 1 to 3.   An anisotropic conductive connector in which electronic parts are anisotropically conductively connected using the anisotropic conductive film according to claim 1.