JP2006160953A - Epoxy-based curable composition and electronic part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy-based curable composition which not only is excellent in rapid curability but also can enhance reliability of joining between members to be joined and hardly causes decrease in reliability of the joining due to impurities such as chlorine. <P>SOLUTION: The epoxy-based curable composition comprises an epoxy compound, a curing agent for the epoxy compound and a curing accelerator for accelerating cure by the curing agent, where the curing accelerator comprises at least either one curing accelerator of a microcapsule curing accelerator and an amine adduct curing accelerator, and an imidazole curing accelerator. The electronic part 1 is equipped with an electronic part element 2 and a substrate 4 on which the electronic part element 2 is mounted, where the electronic part element is joined on the substrate 4 using a cured product 6 comprised of the epoxy-based curable composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an epoxy-based curable composition and an electronic component used for bonding an electronic component element such as a semiconductor chip, for example. More specifically, the present invention provides not only excellent curability but also reliable bonding. The present invention relates to an epoxy-based curable composition and an electronic component that can be provided.

  In the semiconductor chip, in order to improve various reliability, a structure in which the semiconductor chip is housed in a package or mounted on a package material is used. In recent years, in order to achieve miniaturization and thinning, flip chip mounting has been widely used when packaging semiconductor chips. In the flip chip mounting method, a circuit formation surface of a semiconductor chip is used as a lower surface, and metal bumps for electrically connecting to an electrode land on the package side are provided on the lower surface so as to protrude downward.

  In the flip chip mounting method, there is a possibility that the circuit forming surface which is the lower surface of the semiconductor chip is not sufficiently protected. For this reason, moisture and ionic impurities are likely to enter, and reliability may be reduced. Therefore, conventionally, an epoxy resin composition is filled as an underfill material in the gap between the circuit forming surface, which is the lower surface of the semiconductor chip, and the substrate to reinforce the joint and protect the semiconductor chip. There are various methods for interposing this type of resin composition. In general, a method is used in which a liquid epoxy resin composition is dropped around a semiconductor chip and impregnated in a gap between the lower surface of the semiconductor chip and the substrate by a capillary phenomenon.

  However, this method is very poor in productivity and yield. Therefore, in the following Patent Document 1, the underfill material is first applied on the substrate, and then the semiconductor chip is pressed from above, the metal bumps push the underfill material away, and the metal bumps are placed on the substrate. A method of joining to an electrode is employed. This method is called the NCF method (Non-Conductive Film method). In this method, the metal bumps and the electrodes on the substrate are brought into contact with each other at the time of pressure contact, and conduction is achieved. And the thermosetting epoxy resin composition is hardened | cured by utilizing a hot press in the case of pressure welding.

  By the way, in order to electrically connect the metal bump and the electrode on the substrate, an anisotropic conductive film or sheet made of an epoxy-based cured product in which conductive particles are dispersed is used as the underfill material. Yes. That is, a semi-cured anisotropic conductive film in which conductive particles are dispersed is interposed between the metal bump and the electrode on the substrate, and the metal bump and the electrode on the substrate are pressed against each other by hot pressing.

  In this case, when the metal bump is pressed against the electrode side, the semi-cured anisotropic conductive film is pushed away, and the conductive particles dispersed inside adhere to the metal bump and the electrode, so that electrical connection is made. Reliability is improved. On the other hand, an insulating resin material exists between the conductive particles. Therefore, after curing, insulation is ensured in the surface direction of the conductive film, that is, the surface direction of the upper surface of the substrate.

However, with the miniaturization of electronic components, the arrangement density of electrodes on a substrate is increasing. That is, a large number of electrodes connected to different potentials are formed on the substrate, and a large number of metal bumps are pressed against each electrode. In this case, if conductive particles adhere so as to straddle adjacent electrodes connected to different potentials, a short circuit failure occurs. Therefore, when an anisotropic conductive film in which conductive particles are dispersed is used as the underfill material, it is difficult to increase the electrode density on the substrate and the arrangement density of the metal bumps on the semiconductor chip.

In addition, when an underfill material that does not use the conductive particles is used, the reliability of electrical connection is inevitably lowered.
WO2004 / 060996A1

  The present invention eliminates the above-mentioned drawbacks of the prior art, can be cured quickly, and can increase the reliability of joining between members to be joined even when no conductive particles are contained. To provide an electronic component that is configured using the epoxy-based curable composition and the epoxy-based curable composition and has improved reliability of electrical connection between the metal bump and the electrode land. is there.

  According to the present invention, an epoxy compound, a curing agent for the epoxy compound, and a curing accelerator that accelerates curing by the curing agent, the microcapsule type curing accelerator and the amine adduct type curing are used as the curing accelerator. An epoxy-based curable composition comprising at least one curing accelerator with an accelerator and an imidazole-based curing accelerator is provided.

  In the epoxy curable composition according to the present invention, the peak temperature of heat generated by DTA of the epoxy curable composition is preferably 160 ° C. or lower.

  In the epoxy curable composition according to the present invention, an isocyanuric acid-modified imidazole curing accelerator is preferably used as the imidazole curing accelerator.

  The epoxy curable composition according to the present invention preferably further contains a conductive powder.

  An electronic component according to the present invention includes an electronic component element and a substrate on which the electronic component element is mounted, and uses a cured product made of an epoxy-based curable composition configured according to the present invention on the substrate. The electronic component element is bonded.

  In a specific aspect of the electronic component according to the present invention, the electronic component element has a metal bump, and an electrode land electrically connected to the metal bump is formed on the substrate. And the electrode land are joined by a cured product of the epoxy-based curable composition.

  Details of the present invention will be described below.

  The epoxy-based curable composition according to the present invention includes a microcapsule-type curing as a curing accelerator in a composition including an epoxy compound, a curing agent for the epoxy compound, and a curing accelerator that accelerates curing by the curing agent. It includes at least one curing accelerator of an accelerator and an amine adduct type curing accelerator, and an imidazole curing accelerator. In the present invention, by using these curing accelerators, even when conductive particles are not contained, the reliability of joining between members to be joined is effectively enhanced.

(Microcapsule type curing accelerator and / or amine adduct type curing accelerator)
The microcapsule-type curing accelerator used in the epoxy-based curable composition of the present invention is a microencapsulated curing accelerator. In the microcapsule type curing accelerator, the curing accelerator itself to be microencapsulated is not particularly limited.

  In general, in the curing reaction of an epoxy compound, the epoxy compound reacts with a curing agent and undergoes addition polymerization or anionic polymerization to proceed curing. The curing accelerator has a function of catalytically promoting such a reaction.

  As the curing accelerator used in the microcapsule type curing accelerator, for example, an amine-based curing accelerator is preferably used. The property of the amine-based curing accelerator is not particularly limited, but for microencapsulation, an amine-based curing agent that is solid at room temperature is preferable so that it can be powdered at room temperature, and more preferably, the melting point is high. An amine curing agent having a temperature of 40 ° C. or higher is desirable.

  The amine curing agent is not particularly limited, but is an aromatic polyvalent amine such as phenylenediamine, tolylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone; diaminocyclohexylmethane, 3,9-bis (3-aminopropyl) 2 , 4,8,10-tetraoxaspiro (5,5) undecane, etc .; addition reaction products of these polyamines with epoxy resins and / or monoepoxy compounds; ethylenediamine, xylylene diene Polyamide amines obtained by condensing diamines such as amines with dicarboxylic acids such as adipic acid and dimer acid; 2-methylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl 2-Methylimidazole trimellit Imidazole compounds such as salts; addition reaction products of the imidazole compounds and the epoxy resin (A); imidazoline compounds such as 2-methylimidazoline; guanidine compounds such as dicyandiamide; 1,4-diazabicyclo [2,2, 2] tertiary amine compounds such as octane; and compounds such as novolak salt of 1,8-diazabicyclo [5,4,0] undecene-7.

  As a method for microencapsulating the amine curing accelerator, a known microencapsulation method can be used. For example, a method of coating with a material capable of forming a film on the fine powder particle surface of the amine-based curing agent, or a functional group of the curing accelerator present in the surface layer of the fine powder particle of the amine-based curing accelerator, And a method of blocking with other reactive substances that can be reacted with.

  Moreover, as a microcapsule type hardening accelerator, a commercially available microcapsule type hardening accelerator can also be used. Examples of commercially available microcapsule type curing accelerators include, for example, trade name: MCE-9957 (manufactured by Nippon Kayaku Co., Ltd., using methyl methacrylate as a shell part), NovaCure (product of Asahi Ciba) Name: HX-3748, 3741, 3742, HX-3922HR, HX-3941HP) and the like.

  As for the said microcapsule type hardening accelerator, only 1 type may be used and 2 or more types may be used together.

  The amine adduct type curing accelerator is a curing accelerator in the form of an addition compound obtained by reacting amines with various compounds. In general, an adduct type compound refers to an addition compound obtained by reacting a compound having catalytic activity with various compounds. When the compound having catalytic activity is an amine compound such as an imidazole compound or a compound having a primary, secondary or tertiary amino group, an amine adduct type compound is obtained by the above addition reaction.

Depending on the type of compound being adducted, amine-epoxy adduct curing accelerators, amine-ureidoduct curing accelerators, amine-urethane adduct curing accelerators, and the like exist as amine adduct curing accelerators. . Among them, an amine-epoxy adduct-based curing accelerator is preferable because it is difficult to foam during curing, and has a low elasticity and good heat resistance and moisture resistance, and more preferably an epoxy compound is a long chain. The amine-epoxy adduct curing accelerator is more preferred because of its higher potential.

  The amine-epoxy adduct curing accelerator is a solid that is insoluble in an epoxy compound at room temperature, solubilized when heated, and functions as a curing accelerator. As described above, the amine-epoxy adduct-based latent curing accelerator is an addition compound obtained by reacting amines with an epoxy compound. The surface of these addition compounds may be treated with an isocyanate compound or an acidic compound.

Examples of the epoxy compound used as a raw material for producing an amine-epoxy adduct-based latent curing accelerator include polyhydric phenols such as bisphenol A, bisphenol F, catechol, and resorcinol, or polyhydric alcohols such as glycerin and polyethylene glycol and epichlorohydrin. Polyglycidyl ether obtained by reacting glycidyl ether, or glycidyl ether ester obtained by reacting hydroxycarboxylic acid such as p-hydroxybenzoic acid or β-hydroxynaphthoic acid with epichlorohydrin, or polycarboxylic acid such as phthalic acid or terephthalic acid It is obtained by reacting epichlorohydrin with polyglycidyl ester obtained by reacting chlorohydrin with epichlorohydrin or 4,4′-diaminodiphenylmethane or m-aminophenol. Glycidylamine compounds, polyfunctional epoxy compounds such as epoxidized phenol novolak resin, epoxidized cresol novolac resin, epoxidized polyolefin, and monofunctional epoxy compounds such as butyl glycidyl ether, phenyl glycidyl ether, glycidyl methacrylate, etc. Although it is mentioned, it is not limited to these.

The amines used as a raw material for producing an amine-epoxy adduct-based latent curing accelerator have at least one active hydrogen capable of addition reaction with an epoxy group in the molecule, and a primary amino group, a secondary amino group, Any one having at least one substituent selected from tertiary amino groups in the molecule may be used. Examples of such amines include aliphatic amines such as diethylenetriamine, triethylenetetramine, n-propylamine, 2-hydroxyethylaminopropylamine, cyclohexylamine, 4,4′-diamino-dicyclohexylmethane, Aromatic amines such as 4′-diaminodiphenylmethane and 2-methylaniline;
Nitrogen-containing heterocyclic compounds such as 2-ethyl-4-methylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazoline, 2,4-dimethylimidazoline, piperidine, piperazine, etc. It is not something. Among these compounds, a compound having a tertiary amino group is a raw material that provides a curing accelerator having a very high potential. Examples of such compounds are shown below, but are not limited thereto. For example, amine compounds such as dimethylaminopropylamine, diethylaminopropylamine, di-n-propylaminopropylamine, dibutylaminopropylamine, dimethylaminoethylamine, diethylaminoethylamine, N-methylpiperazine, 2-methylimidazole, There are primary or secondary amines having a tertiary amino group in the molecule, such as imidazole compounds such as ethylimidazole, 2-ethyl-4-methylimidazole, and 2-phenylimidazole. The same thing can be used for the amine compound used as a raw material of an amine-ureidoduct type latent curing accelerator and an amine-urethane adduct type latent curing accelerator.

In producing the amine-urethane adduct-based latent curing accelerator, the isocyanate compound as a treating agent used for capping the activity of the amine is not particularly limited, but various isocyanate compounds may be used. Can be used. Such isocyanate compounds include tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, diphenylsulfone diisocyanate, triphenylmethane diisocyanate, hexamethylene diisocyanate, 3-isocyanate methyl-3,5,5- Trimethylcyclohexyl isocyanate, 3-isocyanatoethyl-3,5,5-trimethylcyclohexyl isocyanate, 3-isocyanatoethyl-3,5,5-triethylcyclohexyl isocyanate, diphenylpropane diisocyanate, phenylylene diisocyanate, cyclohexylene diisocyanate, 3,3 '-Diisocyanate dipropyl ether, triphenylmethane triisocyanate Polyisocyanate compounds such as anate, diphenyl ether-4,4′-diisocyanate, dimers or trimers thereof, adducts of these polyisocyanate compounds with polyhydric alcohols such as trimethylolpropane, glycerin, etc. is there.

  As the amine adduct type curing accelerator used in the present invention, various commercially available amine adduct type curing accelerators can be used. Examples of such commercially available products include the following amine adduct type curing accelerators. That is, as an amine-epoxy adduct type curing accelerator, Ajinomoto Co., Inc., trade name: Amicu PN-23, Amicure MY-24, Amicure MY-D, Amicure MY-H, etc. Trade names: Hardener X-3615S, Hardener X-3293S, etc., manufactured by Pacific Anchor Chemical Company, trade names: Ancamine 2014AS or Ancamine 2014FG, etc. Moreover, as an amine-ureido type adduct hardening accelerator, the Fuji Kasei company make, a brand name: Fujicure FXE-1000, Fujicure FXR-1030, etc. are marketed.

  As for the said amine adduct type hardening accelerator, only 1 type may be used and 2 or more types may be used together.

  The microcapsule type curing accelerator and at least one of the amine adduct type curing accelerators are contained, and the blending ratio of these is 0.1 in total with respect to 100 parts by weight of the epoxy compound described later. It is preferable to set it as the range of -20 weight part, More preferably, it is 1.0-15 weight part. If the amount is less than 0.1 parts by weight, the curing rate may be extremely slow, and a good adhesive cured product may not be obtained. If the amount exceeds 20 parts by weight, the pot life may be shortened and the operation may be difficult. .

(Imidazole curing accelerator)
In the epoxy curable composition according to the present invention, an imidazole curing accelerator is contained. Although it does not specifically limit as an imidazole type hardening accelerator, The imidazole type hardening accelerator shown by following General formula (1) is used suitably.

Note that R ¹ and R ² may be the same or different. Furthermore, R ¹ above
And R ² may be a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms. In this case, preferably, it is preferably a substituted or unsubstituted monovalent carbon group having 1 to 6 carbon atoms. A hydrogen group is desirable. Examples of such a monovalent hydrocarbon group include alkyl groups such as methyl group, ethyl group, hedroxy group, and phenyl group, substituted alkyl groups in which these alkyl groups are substituted, and aryl groups. The substituted or unsubstituted monovalent hydrocarbon group constituting R ³ also includes an appropriate substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms. Examples thereof include an alkyl group such as a methyl group, an ethyl group, a phenyl group, and an aryl group, an alkenyl group, and an aryl group. The substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms constituting R ⁴ is preferably a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms. Examples of such monovalent carbonic hydroxyl groups include alkyl groups such as methyl, ethyl, cyanoethyl, and benzyl groups, substituted alkyl groups, and aralkyl groups.

In addition, examples of the substituted monovalent hydroxyl group in R ^{1 to} R ⁴ described above include a hydroxyl group substituted with hydroxy and a hydroxyl group substituted with cyano.

More specifically, examples of the imidazole curing accelerator include 2-methylimidazole, 2-ethylimidazole, 2-undecylimidazole, 2,4-dimethylimidazole, 2-heptadecylimidazole, and 1,2. -Dimethylimidazole, 1,2-diethylimidazole, 2-phenyl-4-methylimidazole, 2,4,5-triphenylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-benzyl-2- Phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-benzyl-2-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-aryl-4,5 -Diphenylimidazole, 2,4- Amino-6- [2′-methylimidazolyl- (1) ′]-ethyl-S-triazine, 2,4-diamino-6- [2′-ethyl-4′-methylimidazolyl- (1) ′]-ethyl -S-triazine, 2,4-diamino-6- [2'-methylimidazolyl- (1) ']-ethyl-S-triazine isocyanuric acid adduct, 2-phenyl-4-methyl-5-hydroxymethylimidazole Etc.

  Among them, an isocyanuric acid-modified imidazole curing accelerator is preferably used because both storage stability and curability can be achieved. Such isocyanuric acid-modified imidazole curing accelerators are commercially available from Shikoku Kasei Co., Ltd. More specifically, 2,4-diamino-6- [2′-methylimidazolyl- (1) ′]-ethyl-S-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, and 2 methylimidazole isocyanuric. Examples include acid adducts, 2,4-diamino-6-vinyl-S-triazine isocyanuric acid adducts, 2,4-diamino-6-methacryloyloxyethyl-S-triazine isocyanuric acid adducts, and the like.

As for the said imidazole series hardening accelerator, only 1 type may be used and 2 or more types may be used together.

  About the mixture ratio of the said imidazole series hardening accelerator, it is preferable to set it as the range of 0.1-20 weight part with respect to 100 weight part of epoxy compounds, More preferably, it is 1.0-15 weight part. If the amount is less than 0.1 parts by weight, the curing rate may be extremely slow, and a good cured product may not be obtained. If the amount exceeds 20 parts by weight, the pot life is shortened, and the electrical characteristics deteriorate due to remaining. May cause.

  In addition, the ratio of the compounding amount of the microcapsule type curing accelerator and / or amine adduct type curing accelerator described above and the compounding amount of the imidazole-based curing accelerator is 10: 0.5 to 0.5: by weight. A ratio of 10 is preferable. When the blending ratio of the microcapsule type curing accelerator and / or the amine adduct type curing accelerator is larger than 10: 0.5, ionic impurities may increase, and the microcapsule type curing is more than 0.5: 10. When the blending ratio of the accelerator and / or the amine adduct type curing accelerator is small, the curing speed may be poor.

(Curing agent)
As described above, the epoxy-based curing composition according to the present invention contains a curing agent that causes a curing reaction by an equivalent reaction with the epoxy compound. As such an epoxy curing agent, a known curing agent conventionally known as an epoxy compound curing agent can be used. Examples of such curing agents include phenolic curing agents, acid anhydride curing agents, latent curing agents (such as dicidiamide), and diamine curing agents. Among them, an acid anhydride curing agent is preferably used because it is easy to adjust the viscosity and does not deteriorate the electrical characteristics of the cured product.

  The anhydride-based curing agent is not particularly limited, and examples thereof include phthalic anhydride, tetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, hymic anhydride, succinic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. These may be used alone or in combination of two or more.

  About the compounding ratio of a hardening | curing agent, it is preferable to add in 0.8 to 0.5 times by equivalence ratio with respect to the epoxy group of an epoxy compound. This is because when the equivalent ratio exceeds 0.8, excess acid anhydride may remain, and the physical properties of the cured product may deteriorate. This is because an ionic reaction to the epoxy compound may occur, which may result in a cured product having poor stress relaxation properties.

(Epoxy compound)
The epoxy compound used as a curing component in the epoxy curable composition of the present invention refers to an organic compound having at least one oxirane ring. The epoxy compound is not particularly limited, and examples thereof include the following various epoxy resins and epoxy-containing compounds. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol type epoxy resin such as bisphenol S type epoxy resin, novolac type epoxy resin such as phenol novolac type epoxy resin, cresol novolac type epoxy resin, Aromatic epoxy resins such as trisphenol methane triglycidyl ether, naphthalene type epoxy resins, dicyclopentadiene type epoxy resins, hydrogenated products and brominated products thereof; 3,4-epoxycyclohexylmethyl-3,4-epoxy Cyclohexanecarboxylate, 3,4-epoxy-2-methylcyclohexylmethyl 3,4-epoxy-2-methylcyclohexanecarboxylate, bis (3,4-epoxycyclohexyl) Le) adipate, bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4-epoxy -6
-Methylcyclohexylmethyl) adipate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexanone-meta-dioxane, bis (2,3-epoxycyclopentyl) ether, trade name "EHPE -3150 "(softening temperature 71 ° C, manufactured by Daicel Chemical Industries, Ltd.) and the like; 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol tri Glycidyl ether, triglycidyl ether of trimethylolpropane, diglycidyl ether of polyethylene glycol, diglycidyl ether of polypropylene glycol, polyoxyalkylene glycol containing an alkylene group having 2 to 9 carbon atoms (preferably 2 to 4 carbon atoms) Polite Aliphatic epoxy resins such as polyglycidyl ethers of long-chain polyols including methylene ether glycol; phthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, diglycidyl-p-oxybenzoic acid Glycidyl ester type epoxy resins such as glycidyl ether-glycidyl ester of salicylic acid, dimer acid glycidyl ester and the like; and hydrogenated products thereof; triglycidyl isocyanurate, N, N′-diglycidyl derivative of cyclic alkylene urea, p-aminophenol Glycidylamine type epoxy resins such as N, N, O-triglycidyl derivatives of N, N, O-triglycidyl derivatives of m-aminophenol and the like; hydrogenated products thereof; ) A copolymer of an acrylate and a radical polymerizable monomer such as ethylene, vinyl acetate, (meth) acrylic acid ester; a polymer mainly composed of a conjugated diene compound such as epoxidized polybutadiene or a partially hydrogenated product thereof An epoxidized double bond of unsaturated carbon of a polymer of "Polymer block mainly composed of vinyl aromatic compound" and "Polymer block mainly composed of conjugated diene compound" such as epoxidized SBS Or a partially copolymerized block copolymer having an epoxidized double bond of unsaturated carbon of a conjugated diene compound; NBR, Rubber-modified epoxy resin containing rubber components such as CTBN, polybutadiene, and acrylic rubber; Thing, and the like.

  As for the said epoxy compound, only 1 type may be used and 2 or more types may be used together.

  Among the above epoxy compounds, at least, by using a polymer containing a large amount of an epoxy group, the heat resistance in a cured product obtained by curing the curable composition of the present invention can be dramatically increased, which is desirable. . The polymer containing a large amount of such epoxy groups is not particularly limited, but an epoxy group-containing acrylic polymer is preferably used.

  The weight average molecular weight of the epoxy group-containing polymer is preferably in the range of 5,000 to 200,000, more preferably in the range of 10,000 to 100,000. When the weight average molecular weight is less than 5,000, the effect of improving the heat resistance may not be obtained, and when it exceeds 200,000, the storage stability may be lowered.

  When using the said epoxy group containing polymer, when the said epoxy compound whole is 100 weight part, it is desirable to use in the range of 1 weight part-10 weight part in 100 weight part. If the amount is less than 1 part by weight, the effect of improving the heat resistance may not be obtained so much. If the amount exceeds 10 parts by weight, the viscosity becomes too high when a paste made of the curable composition is produced, There is a risk that problems such as these are likely to occur. The epoxy equivalent of the epoxy group-containing polymer is preferably in the range of 200 to 1,000. An epoxy group-containing polymer having an epoxy equivalent in the range of 200 to 1,000 is desirable because it has excellent compatibility with other epoxy monomers, and thus can improve the heat resistance of the resulting cured product.

(Conductive powder)
The curable composition according to the present invention may further contain conductive powder such as metal powder, if necessary. Examples of such conductive powder include metal powder such as Ag, Cu, Al, Au, or conductive particles in which a conductive film is formed on the surface of synthetic resin particles, and are not particularly limited. By containing the conductive powder, conductivity can be imparted to the cured product obtained by curing the curable composition according to the present invention. Therefore, not only the joining between members but also electrical connection can be achieved using the cured product.

  When the conductive powder is contained, the conductive powder is blended in the range of 0.2 to 20 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the epoxy compound in the curable composition. It is desirable. If the amount is less than 0.2 parts by weight, sufficient conductivity may not be obtained. If the amount exceeds 20 parts by weight, the physical properties of the cured product may be deteriorated.

(Other additives)
Other additives may be added to the epoxy-based curable composition according to the present invention as necessary, as long as the object of the present invention is not impaired. Examples of such additives include aliphatic hydroxyl group-containing compounds, thermoplastic resins, adhesion improvers, fillers, reinforcing materials, softeners, plasticizers, viscosity modifiers, thixotropic agents, stabilizers, antioxidants, Coloring agents, dehydrating agents, flame retardants, antistatic agents, foaming agents, antifungal agents and the like can be mentioned. Only one kind of these additives may be used, or two or more kinds may be added.

  Moreover, 1 type (s) or 2 or more types of various thermoplastic resins may be mix | blended with the epoxy-type curable composition which concerns on this invention as another resin component.

(Production method)
The manufacturing method of the epoxy-type curable composition which concerns on this invention is not specifically limited, It can obtain by disperse | distributing and mixing the said various components uniformly. The dispersion / mixing method is not particularly limited, and examples thereof include a dispersion / kneading method using a three-roller, a raking machine, a planetary mixer, and the like. During mixing, the pressure may be reduced as necessary. Moreover, it is desirable to mix each component by using a planetary stirrer, whereby each component can be mixed uniformly and easily while avoiding the mixing of metal.

(Electronic parts)
An electronic component according to the present invention is an electrode land in which an electronic component element and an electronic component element are electrically connected by a cured product obtained by curing the epoxy-based curable composition configured according to the present invention. It is characterized by being bonded to an electrode land of a substrate having a surface thereof. Although it will not specifically limit if it is such a structure, Preferably, the electronic component element has a metal bump, and the structure where this metal bump is joined to the electrode land on a board | substrate with the said hardened | cured material can be mentioned. Such a structure is a structure in which an electronic component element is mounted on a substrate by the above-described flip chip mounting method, and is widely used for mounting a package substrate of a semiconductor chip, for example.

  FIG. 1 is a front sectional view schematically showing an example of such an electronic component of the present invention. In the electronic component 1, the electronic component element 2 has a plurality of metal bumps 3 on the lower surface. A plurality of electrode lands 5 are formed on the upper surface of the substrate 4. Here, the metal bump 3 and the electrode land 5 are joined and electrically connected by the sheet-like cured product 6 obtained by curing the epoxy-based curable composition constituted according to the present invention. .

The bonding method is not particularly limited, but a semi-cured sheet-like epoxy curable composition is disposed on the substrate 4, and the side on which the metal bumps 3 of the electronic component element 2 are formed from above is used as the lower surface. What is necessary is just to make it press-contact and heat in the case of this press-contact. At the time of press contact, the sheet-like epoxy curable composition is pushed away by the metal bump 3, and the metal bump 3 is mounted on the electrode land 5. And the sheet-like curable composition hardens | cures by heating, and the sheet-like hardened | cured material 6 is formed. However, the present invention can also be applied to an electronic component formed by bonding an electronic component element not having the metal bump 3 to an electrode land on a substrate.

  Also for the electronic component element, various active components or passive components other than the semiconductor chip can be used. Furthermore, the board is not limited to a circuit board on which various electronic component elements are mounted, and may be a package material or the like.

  The epoxy curable composition according to the present invention contains at least one of a microcapsule type curing accelerator and an amine adduct type curing accelerator, and an imidazole type curing accelerator as a curing accelerator. Yes. Here, the microcapsule type curing accelerator and the amine adduct type curing accelerator are latent curing accelerators, and therefore, it is possible to improve the storage stability of the epoxy-based curable composition according to the present invention. Yes. In addition, according to the curing promoting action of the microcapsule type curing accelerator and the amine adduct type curing accelerator, the initial curing reaction is effectively accelerated.

  However, when only a microcapsule type curing accelerator or an amine adduct type curing accelerator is used, although the initial curing reaction is accelerated, the curing proceeds and the gel fraction is saturated at about 90%. As described above, the gel fraction (degree of crosslinking) does not increase. Further, there has been a problem that a reaction for extracting chlorine ions bonded to the epoxy compound occurs, and impurities such as chlorine ions bonded to other substances are generated. When such impurities are present, for example, when used as the above-described underfill material in the mounting structure of an electronic component, the reliability of electrical connection may be impaired.

  On the other hand, when only an imidazole series hardening accelerator is used, the above impurities are hard to be generated. However, with an imidazole-based curing accelerator, there is a possibility that the reactivity when accelerating the curing reaction is not sufficient.

  Therefore, in the present invention, by using the above microcapsule type curing accelerator and / or amine adduct type curing accelerator, the curing reaction rate in the initial state is increased, and the fast curing property is realized. In the later stage, the curing reaction proceeds sufficiently by the action of the imidazole curing accelerator. Therefore, it is possible to achieve both quick curability and improved bonding reliability by the cured product. As described above, since the reliability of bonding with the cured product is improved, the curable composition according to the present invention is cured in a state where the members to be conducted are brought into contact with each other even when the conductive powder is not included. It is also possible to reliably maintain the conduction state simply by making it.

  In particular, when the exothermic peak temperature due to DTA is 160 ° C. or lower, the curing rate is increased.

  When the imidazole curing accelerator is an isocyanuric acid-modified imidazole curing accelerator, the storage stability and curability of the epoxy curable composition can be further enhanced.

  When a conductive powder is further contained, a cured product having conductivity can be provided according to the present invention. Therefore, for example, in an electronic component mounting structure, it is possible to achieve electrical connection by the cured product itself.

In the electronic component according to the present invention, the electronic component element is bonded onto the substrate using the cured product of the epoxy-based curable composition of the present invention, and is quickly cured, so that the productivity is excellent. In addition, it is possible to provide a mounting structure with excellent connection reliability. In particular, when the metal bumps of the electronic component and the electrode lands on the substrate are bonded with the cured product of the epoxy-based curable composition, the reliability of the bonding between the metal bumps and the electrode lands is improved. In addition, the reliability of the electrical connection can be further improved.

  Hereinafter, the present invention will be clarified by describing specific examples and comparative examples of the present invention. The present invention is not limited to the following examples.

(Materials used)
(1) Epoxy compound Epoxy group-containing acrylic polymer: manufactured by NOF Corporation, product number: CP-30, weight average molecular weight 10,000, epoxy equivalent 500
Naphthalene type epoxy: manufactured by Dainippon Ink, product number: HP-4032D
Dicyclopentadiene type epoxy compound: manufactured by Dainippon Ink Co., Ltd., product number: HP-7200
(2) Curing agent Trialkyltetrahydrophthalic anhydride: manufactured by JER, product number: YH-306
Trialkyltetrahydrophthalic anhydride: manufactured by JER, product number: YH-307
(3) Curing accelerator Isocyanuric acid addition type triazine type imidazole: manufactured by Shikoku Kasei Kogyo Co., Ltd., product number: 2MAOK-PW
1-cyanoethyl-2-phenylimidazole: manufactured by Shikoku Kasei Kogyo Co., Ltd., product number: 2PZ-CN
Amine adduct imidazole: manufactured by Ajinomoto Fine Techno Co., product number: PN-23J
Microcapsule type latent curing agent: manufactured by Asahi Kasei Co., Ltd., product number: HX-3748
(4) Adhesiveness imparting agent Imidazole silane coupling agent: manufactured by Nikko Materials Co., Ltd., product number: SP-1000

Example 1
The above materials were weighed into a 200 ml plastic container so as to have the composition shown in Table 1 below, and uniformly mixed with a planetary stirrer to obtain a paste. This paste was subjected to pressure filtration using a polyester mesh having an opening diameter of 20 μm, and further filled into a 10 ml syringe to obtain a curable composition of Example 1.

(Examples 2-7 and Comparative Examples 1-3)
As shown in Table 1 below, a curable composition was obtained in the same manner as in Example 1 except that the blending ratio of the used materials was changed.

(Evaluation of Examples and Comparative Examples)
About each said curable composition, (1) Measurement of exothermic temperature by DTA, (2) Electrical connection and mechanical joint evaluation, (3) TCT thermal cycle test, and (4) Measurement of Cl ion impurity concentration are as follows. I went there.

  (1) Measurement of exothermic temperature by DTA: About the curable composition paste, the exothermic peak was observed using TG / DTA6000 by Seiko Instruments Inc. That is, about 10 mg of paste was weighed into an aluminum pan, and the temperature was raised at a rate of temperature increase of 10 ° C./min. The temperature of the maximum exothermic peak at this time was read and used as the exothermic temperature.

(2) Reliability evaluation of bonding and electrical connection A plurality of stud bumps (diameter: 100 μm and protruding height: about 50 μm) made of wire bonding and having a planar shape of 10 × 10 mm are formed on the periphery of the lower surface 172 IC chips arranged along with the glass / epoxy FR-4 substrate having a thickness of 20 mm × 20 mm × 1.0 mm. A wiring pattern is formed on the surface of the substrate in accordance with the density of the stud bumps. The wiring pattern has a structure in which a 5 μm nickel plating film and a 0.3 μm gold plating film are laminated on a 18 μm thick copper foil.

A curable composition paste is discharged onto the wiring pattern of the substrate, and the IC chip is placed from the side where the stud bump on the lower surface protrudes, and a load of 78 N / cm ² is applied while the temperature is 200 ° C.
Was heated at a temperature of 30 seconds for bonding. Thereafter, it was cured at a temperature of 125 ° C. for 1 hour to obtain a conductive joined body. The temperature at the time of joining was measured by inserting a thermocouple into the curable composition paste.

  The conductivity of the conductive assembly obtained as described above was evaluated by the presence or absence of electrical conduction between the stud bump and the wiring pattern on the substrate side, and the property of the cured product of the curable composition paste was determined by the degree of cure of the fillet portion. Based on the evaluation. The results are shown in Table 1 below. The meanings of the evaluation symbols in Table 1 are as follows.

○… No continuity failure △… No continuity failure, curing of the paste of the curable composition is incomplete, progressing ×… Conductivity failure and / or insufficient progress

(3) TCT thermal cycle test (2) About the conducting joint in which the conduction failure did not occur, after confirming that it has high conduction resistance stability at room temperature (20 ° C), it is maintained at -40 ° C for 10 minutes. Then, after that, a cold cycle test was performed using a cold cycle tester for performing a cold cycle maintained at 125 ° C. for 10 minutes. The conductive joined body was taken out at an appropriate number of cycles, the change in the conductive resistance value was confirmed, and the number of cooling cycles in which the conductive resistance value decreased by 10% or more from the intended state was determined.

(4) Measurement of chlorine ion concentration The curable composition paste was cured by heating in an oven at 170 ° C. for 30 minutes, and about 1 mg of the cured product was weighed out. This 1 mg cured product is finely pulverized, put into a glass test tube, 10 g of distilled water is added, the test tube is sealed with a burner, and heated and extracted for 12 hours with occasional rocking in an oven at 110 ° C. Went. Using ion chromatography, the chloride ion impurity concentration (ppm) in the obtained extracted water was measured.

  As is apparent from Table 1, in Examples 1 to 7 in which a microcapsule type curing accelerator and / or an amine adduct type curing accelerator and imidazole are used in combination as curing accelerators, the curing itself proceeds rapidly. It was found that the amount of impurities of chlorine ions during extraction was small and the reliability in the cold cycle test was also excellent.

  On the other hand, in Comparative Examples 1 and 2 using only the microcapsule type curing accelerator and / or the amine adduct type curing accelerator, it was found that the amount of pure chlorine ions was large and the reliability of bonding was low. Furthermore, in Comparative Example 3, the curing rate was not sufficient because only the imidazole-based curing accelerator was used.

BRIEF DESCRIPTION OF THE DRAWINGS Front sectional drawing which shows an example of the electronic component with which the electronic component element was joined to the board | substrate with the hardened | cured material of the epoxy-type curable composition of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electronic component 2 ... Electronic component element 3 ... Metal bump 4 ... Board | substrate 5 ... Electrode land

Claims (6)

An epoxy compound, a curing agent for the epoxy compound, and a curing accelerator that accelerates curing by the curing agent,
An epoxy-based curable composition comprising, as the curing accelerator, at least one of a microcapsule-type curing accelerator and an amine adduct-type curing accelerator, and an imidazole-based curing accelerator.   2. The epoxy curable composition according to claim 1, wherein an exothermic peak temperature by DTA is 160 ° C. or less.   The epoxy curable composition according to claim 1 or 2, wherein the imidazole curing accelerator is an isocyanuric acid-modified imidazole curing accelerator.   The epoxy curable composition according to claim 1, further comprising a conductive powder. An electronic component element, and a substrate on which the electronic component element is mounted,
An electronic component, wherein the electronic component element is bonded onto the substrate using a cured product made of the epoxy curable composition according to any one of claims 1 to 4. The electronic component element has a metal bump, and an electrode land electrically connected to the metal bump is formed on the substrate, and the metal bump and the electrode land are formed of the epoxy-based curable composition. The electronic component according to claim 5, wherein the electronic component is joined by a cured product.

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