JP5354192B2 - Thermosetting conductive paste composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable low-temperature fast-curing of a glycidyl ether type epoxy resin with an aluminum chelate-based latent curing agent without using a cycloaliphatic epoxy compound and to achieve good storage stability, in a thermosetting conductive paste composition prepared by blending conductive particles with a thermosetting epoxy resin composition containing the aluminum chelate-based latent curing agent and the glycidyl ether type epoxy resin. <P>SOLUTION: The thermosetting conductive paste composition includes an aluminum chelate-based latent curing agent, a silanol compound represented by formula (A), a glycidyl ether type epoxy resin, and a conductive material. In the formula, m is 2 or 3, provided that the sum of m and n is 4; and Ar is an aryl group which may be substituted. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a thermosetting conductive paste composition comprising a thermosetting epoxy resin composition containing an aluminum chelate-based latent curing agent and a glycidyl ether type epoxy resin and a conductive material such as silver powder. .

  Conventionally, a thermosetting conductive paste composition obtained by blending a film forming component, a curing agent, and a conductive material with an epoxy resin has been widely used in the field of semiconductor devices and the like. Here, a microencapsulated aluminum chelate-based latent curing agent in which an aluminum chelating agent is held in a porous resin obtained by interfacial polymerization of a polyfunctional isocyanate compound has been proposed as a curing agent that exhibits low-temperature rapid curing activity for epoxy resins. (Patent Document 1). Moreover, the thermosetting epoxy resin composition in which a silane coupling agent having a polymerizable group such as a vinyl group and a trialkoxy group and an epoxy resin are blended with the aluminum chelate-based latent curing agent is a one-component type. In spite of this, it is said that it has excellent storage stability and has the property of being rapidly cured at low temperature by cationic polymerization (the same patent document).

JP 2006-70051 A

  However, in the case of a thermosetting conductive paste composition based on a thermosetting epoxy resin composition in which an aluminum chelate-based latent curing agent, a silane coupling agent, and an epoxy resin disclosed in Patent Document 1 are blended, by heating When the polymerization (curing) reaction is started, the silanolate anion generated from the silane coupling agent is added to the β-position carbon of the epoxy group of the epoxy resin to cause a polymerization termination reaction. For this reason, with the aluminum chelate-based latent curing agent disclosed in Patent Document 1, it is difficult to polymerize a glycidyl ether-based epoxy resin that is likely to cause a β-carbon addition reaction without causing a polymerization termination reaction. There was a problem that an alicyclic epoxy compound was inevitably used, although the production cost was high but the addition reaction to the β-position carbon due to the silanolate anion was difficult to occur.

  The object of the present invention is to solve the above-mentioned problems of the prior art, and a silver curable powder is added to a thermosetting epoxy resin composition containing an aluminum chelate-based latent curing agent and a glycidyl ether type epoxy resin. In a thermosetting conductive paste composition containing a conductive material, a glycidyl ether-based epoxy resin can be quickly cured at low temperature with an aluminum chelate-based latent curing agent without using an alicyclic epoxy compound. And to achieve good storage stability.

  When the present inventors use a highly sterically hindered silanol compound having a specific chemical structure that has not been conventionally used as a silane coupling agent in combination with an aluminum chelate latent curing agent, the specific silanol compound is unexpectedly formed. Has also found that the polymerization termination reaction can be suppressed and the formation of a cation catalyst can be promoted, so that the above-mentioned object can be achieved, and the present invention has been completed.

  That is, the present invention provides a thermosetting conductive paste composition containing an aluminum chelate-based latent curing agent, a silanol compound of the formula (A), a glycidyl ether type epoxy resin, and a conductive material.

  In formula (A), m is 2 or 3, provided that the sum of m and n is 4. Ar is an aryl group which may be substituted.

  The present invention also provides a semiconductor device in which a semiconductor chip is connected and fixed to a lead frame with the above-mentioned thermosetting conductive paste composition.

  The thermosetting conductive paste composition of the present invention contains a highly sterically hindered silanol compound in addition to the aluminum chelate-based latent curing agent. For this reason, the polymerization termination reaction can be suppressed and the formation of a cation catalyst can be promoted. Therefore, the thermosetting conductive paste composition of the present invention is capable of rapid curing at low temperature, even though it contains a glycidyl ether type epoxy resin that has not been sufficiently polymerized with an aluminum chelate-based latent curing agent. In addition, the storage stability is excellent.

  The thermosetting conductive paste composition of the present invention contains an aluminum chelate-based latent curing agent, a silanol compound, a glycidyl ether type epoxy resin, and a conductive material. Unlike the conventional silane coupling agent having a trialkoxy group, this silanol compound is an arylsilaneol having a chemical structure of the following formula (A).

  In the formula, m is 2 or 3, provided that the sum of m and n is 4. Therefore, the silanol compound of the formula (A) becomes a mono or diol form. “Ar” is an aryl group which may be substituted, and examples of the aryl group include a phenyl group, a naphthyl group, an anthracenyl group, an azulenyl group, a fluorenyl group, a thienyl group, a furyl group, a pyrrolyl group, an imidazolyl group, and a pyridyl group. Etc. Of these, a phenyl group is preferable from the viewpoint of availability and cost. The m Ars may be the same or different, but are preferably the same from the viewpoint of availability.

  These aryl groups can have 1 to 3 substituents, for example, halogen such as chloro and bromo; trifluoromethyl; nitro; sulfo; alkoxycarbonyl such as carboxyl, methoxycarbonyl and ethoxycarbonyl; formyl and the like Electron-withdrawing groups, alkyl such as methyl, ethyl and propyl; alkoxy such as methoxy and ethoxy; hydroxy; amino; monoalkylamino such as monomethylamino; and electron-donating groups such as dialkylamino such as dimethylamino. In addition, the acidity of the hydroxyl group of silanol can be increased by using an electron withdrawing group as a substituent, and conversely, the acidity can be lowered by using an electron donating group, so that the curing activity can be controlled. Become. Here, the substituents may be different for each of the m Ars, but the substituents are preferably the same for the m Ars from the viewpoint of availability. Further, only some Ar may have a substituent, and other Ar may not have a substituent.

  Among the silanol compounds of the formula (A), triphenylsilanol or diphenylsilanol is preferable. Particularly preferred is triphenylsilanol.

  In the thermosetting conductive paste composition of the present invention, regarding the content of the silanol compound of the formula (A), if the content ratio of the silanol compound to the total of the silanol compound and the glycidyl ether type epoxy resin is too small, the curing is insufficient. If the amount is too large, the resin properties (flexibility, etc.) are lowered, so the content is preferably 5 to 30% by mass, more preferably 5 to 20% by mass.

  The silanol compound of formula (A) is preferably dissolved in an epoxy resin prior to use. In this case, the mixture of the silanol compound of the formula (A) and the epoxy resin can be heated and stirred at a temperature of about 80 ° C. for about 2 hours as necessary.

  The glycidyl ether type epoxy resin constituting the thermosetting conductive paste composition of the present invention is used as a film forming component. Such a glycidyl ether type epoxy resin may be liquid or solid, and preferably has an epoxy equivalent of usually about 100 to 4000 and having two or more epoxy groups in the molecule. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, ester type epoxy resin and the like can be mentioned. Among these, bisphenol F type epoxy resins can be preferably used from the viewpoint of resin characteristics. These epoxy resins also include monomers and oligomers.

  In the thermosetting conductive paste composition of the present invention, an alicyclic epoxy compound or the like can be used as a resin component in addition to a glycidyl ether type epoxy resin. Further, an oxetane compound can be used in combination in order to sharpen the exothermic peak. Preferred oxetane compounds include 3-ethyl-3-hydroxymethyloxetane, 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene, 4,4′-bis [(3-ethyl- 3-oxetanyl) methoxymethyl] biphenyl, 1,4-benzenedicarboxylic acid bis [(3-ethyl-3-oxetanyl)] methyl ester, 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl-3- ( 2-ethylhexyloxymethyl) oxetane, di [1-ethyl (3-oxetanyl)] methyl ether, 3-ethyl-3-{[3- (triethoxysilyl) propoxy] methyl} oxetane, oxetanylsilsesquioxane, Phenol novolac oxetane and the like can be mentioned. When the oxetane compound is used, the amount used is preferably 10 to 100 parts by mass, more preferably 20 to 70 parts per 100 parts by mass in total of the glycidyl ether type epoxy resin and the alicyclic epoxy compound added as necessary. Part by mass.

  In addition to the resin component described above, the thermosetting conductive paste composition of the present invention can use a monofunctional reactive diluent as one of the resin components.

  In addition, it is preferable to avoid the use of a resin component having a nitrogen atom in the structure if possible. Further, from the viewpoint of preventing corrosion of the adherend, it is preferable to use one having an impurity ion concentration as low as possible.

  Examples of the aluminum chelate-based latent curing agent constituting the thermosetting conductive paste composition of the present invention include those in which an aluminum chelating agent is made latent by various known techniques, for example, a microencapsulation method. it can. Examples of preferable aluminum chelate-based latent curing agents include those in which an aluminum chelate is held in a porous resin obtained by interfacial polymerization of a polyfunctional isocyanate compound. More specifically, the aluminum chelating agent is held in a large number of fine pores existing in the porous resin matrix, not a microcapsule with a simple structure in which the core of the aluminum chelating agent is covered with a porous resin shell. Can be mentioned. Hereinafter, the aluminum chelate-based latent curing agent will be described.

  Since the aluminum chelate-based latent curing agent is produced using an interfacial polymerization method, its shape is spherical, and its particle size is preferably 0.5 to 100 μm from the viewpoint of curability and dispersibility. The size of the pores is preferably 5 to 150 nm from the viewpoint of curability and potential.

  In addition, the aluminum chelate-based latent curing agent has a tendency to decrease if the degree of crosslinking of the porous resin to be used is too small, and if too large, the thermal responsiveness tends to decrease. It is preferable to use a porous resin whose degree of crosslinking is adjusted. Here, the degree of crosslinking of the porous resin can be measured by a micro compression test.

  It is preferable from the viewpoint of curing stability that the aluminum chelate-based latent curing agent does not substantially contain an organic solvent used at the time of the interfacial polymerization, specifically 1 ppm or less.

  In addition, the epoxy resin and the aluminum chelating agent in the aluminum chelate-based latent curing agent have a low thermal responsiveness when the aluminum chelating agent content is too small, and the latent resin content decreases when the aluminum chelating agent content is too high. The content of the aluminum chelating agent is preferably 1 to 70 parts by mass, more preferably 1 to 50 parts by mass with respect to parts by mass.

  In the aluminum chelate-based latent curing agent, examples of the aluminum chelating agent include a complex compound in which three β-keto enolate anions represented by the formula (1) are coordinated to aluminum.

Here, R ¹ , R ² and R ³ are each independently an alkyl group or an alkoxyl group. Examples of the alkyl group include a methyl group and an ethyl group. Examples of the alkoxyl group include a methoxy group, an ethoxy group, and an oleyloxy group.

  Specific examples of the aluminum chelating agent represented by the formula (1) include aluminum tris (acetylacetonate), aluminum tris (ethylacetoacetate), aluminum monoacetylacetonate bis (ethylacetoacetate), aluminum monoacetylacetonate Examples thereof include bisoleyl acetoacetate, ethyl acetoacetate aluminum diisopropylate, and alkyl acetoacetate aluminum diisopropylate.

  The polyfunctional isocyanate compound is preferably a compound having two or more isocyanate groups, preferably three isocyanate groups in one molecule. As a more preferred example of such a trifunctional isocyanate compound, a TMP adduct of formula (2) obtained by reacting 3 mol of a diisocyanate compound with 1 mol of trimethylolpropane, and a formula (3) obtained by self-condensing 3 mol of a diisocyanate compound. An isocyanurate of formula (4) and a biuret of formula (4) obtained by condensing the remaining 1 mol of diisocyanate with diisocyanate urea obtained from 2 mol of 3 mol of diisocyanate compound.

  In said (2)-(4), the substituent R is the part except the isocyanate group of the diisocyanate compound. Specific examples of such diisocyanate compounds include toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, m-xylylene diisocyanate, hexamethylene diisocyanate, hexahydro-m-xylylene diisocyanate, isophorone diisocyanate, methylene diphenyl-4. , 4'-diisocyanate and the like.

  In the porous resin obtained by interfacial polymerization of such a polyfunctional isocyanate compound, part of the isocyanate group undergoes hydrolysis during the interfacial polymerization to become an amino group, and the amino group reacts with the isocyanate group. It is a porous polyurea that forms a urea bond to polymerize. An aluminum chelate-based latent curing agent comprising such a porous resin and an aluminum chelating agent retained in the pores is retained for a clear reason when heated for curing, although the reason is unknown. The aluminum chelating agent can come into contact with the silanol compound of the formula (1) and the thermosetting resin coexisting with the latent curing agent, and the curing reaction can proceed.

  In addition, when interfacially polymerizing a polyfunctional isocyanate compound, a radical polymerizable monomer such as divinylbenzene and a radical polymerization initiator may be co-polymerized to improve the mechanical properties of the microcapsule wall. Thereby, the thermal response speed at the time of hardening of an epoxy resin can be increased.

  In addition, due to the structure of the aluminum chelate-based latent curing agent, it is thought that the aluminum chelating agent is also present on the surface, but it is inactivated by water present in the system during the interfacial polymerization, and the aluminum chelating agent is Only what is retained inside the porous resin retains activity, and it is considered that the resulting curing agent has acquired the potential.

  The aluminum chelate-based latent curing agent is prepared by dissolving an aluminum chelating agent and a polyfunctional isocyanate compound in a volatile organic solvent, putting the obtained solution into an aqueous phase containing a dispersant, and heating and stirring the interface. It can manufacture by the manufacturing method characterized by making it superpose | polymerize.

  In this production method, first, an aluminum chelating agent and a polyfunctional isocyanate compound are dissolved in a volatile organic solvent to prepare a solution that becomes an oil phase in interfacial polymerization. Here, the reason for using the volatile organic solvent is as follows. That is, when a high boiling point solvent having a boiling point exceeding 300 ° C. as used in a normal interfacial polymerization method is used, the organic solvent does not volatilize during the interfacial polymerization, so the contact probability with isocyanate-water does not increase. This is because the degree of progress of interfacial polymerization between them becomes insufficient. Therefore, it is difficult to obtain a polymer having good shape retention even when interfacial polymerization is performed, and even when it is obtained, when the high boiling point solvent is still taken into the polymer and it is blended in a thermosetting resin composition In addition, the high boiling point solvent adversely affects the physical properties of the cured product of the thermosetting resin composition. For this reason, in this manufacturing method, a volatile thing is used as an organic solvent used when preparing an oil phase.

  Such a volatile organic solvent is a good solvent of an aluminum chelating agent and a polyfunctional isocyanate compound (the solubility of each is preferably at least 0.1 g / ml (organic solvent)), and is substantially free from water. In particular, those having a water solubility of 0.5 g / ml (organic solvent) or less and a boiling point of 100 ° C. or less under atmospheric pressure are preferable. Specific examples of such volatile organic solvents include alcohols, acetate esters, ketones and the like. Among these, ethyl acetate is preferable in terms of high polarity, low boiling point, and poor water solubility.

  The amount of the volatile organic solvent used is preferably from 100 to 100 parts by mass because the latent amount is lowered if the amount is too small and the thermal responsiveness is lowered if the amount is too large relative to 100 parts by mass of the total amount of the aluminum chelating agent and the polyfunctional isocyanate compound. 500 parts by mass.

  Note that the viscosity of the oil phase solution can be lowered by using a relatively large amount of the volatile organic solvent within the range of the volatile organic solvent used. As a result, the oil phase droplets in the reaction system can be made finer and more uniform, and the resulting latent hardener particle size can be controlled to submicron to several microns. The particle size distribution can be monodispersed. The viscosity of the oil phase solution is preferably set to 1 to 2.5 mPa · s.

  In addition, when PVA is used when emulsifying and dispersing the polyfunctional isocyanate compound, the hydroxyl group of PVA reacts with the polyfunctional isocyanate compound, so that by-products adhere around the latent curing agent particles as foreign substances. Or the particle shape itself may be deformed. In order to prevent this phenomenon, the reactivity between the polyfunctional isocyanate compound and water is promoted, or the reactivity between the polyfunctional isocyanate compound and PVA is suppressed.

  In order to promote the reactivity between the polyfunctional isocyanate compound and water, the blending amount of the aluminum chelating agent is preferably ½ or less, more preferably ３ or less by weight of the polyfunctional isocyanate compound. Thereby, the probability that a polyfunctional isocyanate compound and water will contact increases, and it becomes easy for a polyfunctional isocyanate compound and water to react before PVA contacts an oil phase droplet surface.

  Moreover, in order to suppress the reactivity of a polyfunctional isocyanate compound and PVA, increasing the compounding quantity of the aluminum chelating agent in an oil phase is mentioned. Specifically, the blending amount of the aluminum chelating agent is preferably equal to or greater than the weight of the polyfunctional isocyanate compound, more preferably 1.0 to 2.0 times. Thereby, the isocyanate density | concentration in the oil phase droplet surface falls. Furthermore, since the polyfunctional isocyanate compound has a higher reaction rate (interfacial polymerization) with the amine formed by hydrolysis than the hydroxyl group, the reaction probability between the polyfunctional isocyanate compound and PVA can be lowered.

  When the aluminum chelating agent and the polyfunctional isocyanate compound are dissolved in the volatile organic solvent, the aluminum chelating agent and the polyfunctional isocyanate compound may be mixed and stirred at room temperature under atmospheric pressure, but may be heated as necessary.

  Next, in this production method, an oil phase solution in which an aluminum chelating agent and a polyfunctional isocyanate compound are dissolved in a volatile organic solvent is put into an aqueous phase containing a dispersant, and subjected to interfacial polymerization by heating and stirring. Here, as a dispersing agent, what is used in normal interfacial polymerization methods, such as polyvinyl alcohol, carboxymethylcellulose, gelatin, can be used. The usage-amount of a dispersing agent is 0.1-10.0 mass% of an aqueous phase normally.

  The blending amount of the oil phase solution with respect to the aqueous phase is preferably 5 to 50 parts by mass with respect to 100 parts by mass of the aqueous phase because polydispersion occurs when the amount of the oil phase solution is too small, and aggregation occurs due to refinement when the amount is too large. .

  As the emulsification conditions in the interfacial polymerization, stirring conditions (stirring apparatus homogenizer; stirring speed of 8000 rpm or more) such that the size of the oil phase is preferably 0.5 to 100 μm are usually obtained at a temperature of 30 to 80 ° C. under atmospheric pressure. The conditions of stirring with heating for 2 to 12 hours can be mentioned.

  After completion of the interfacial polymerization, the polymer fine particles are filtered off and air-dried to obtain an aluminum chelate-based latent curing agent that can be used in the present invention. Here, the curing characteristics of the aluminum chelate-based latent curing agent can be controlled by changing the type and usage of the polyfunctional isocyanate compound, the type and usage of the aluminum chelating agent, and the interfacial polymerization conditions. For example, if the polymerization temperature is lowered, the curing temperature can be lowered, and conversely, if the polymerization temperature is raised, the curing temperature can be raised.

  If the content of the aluminum chelate-based latent curing agent in the thermosetting conductive paste composition of the present invention is too small, it will not be sufficiently cured, and if it is too large, the resin properties of the cured product of the composition (for example, flexibility) ) Is lowered, the reactivity is increased, and the storage stability is lowered. Therefore, the amount is 1 to 70 parts by mass, preferably 1 to 50 parts by mass with respect to 100 parts by mass of the glycidyl ether type epoxy resin composition.

  In addition, the porous resin obtained by radically polymerizing divinylbenzene simultaneously with the porous resin obtained by interfacial polymerization of a polyfunctional isocyanate compound or the polyfunctional isocyanate compound is an aluminum chelate-based latent curing agent. In the case of an aluminum chelate-based latent curing agent obtained by holding an aluminum chelating agent, an impregnation treatment with an aluminum chelating agent may be performed in order to improve low-temperature fast curing properties. As an impregnation method, an aluminum chelate-based latent curing agent comprising an aluminum chelating agent held in such a porous resin is dispersed in an organic solvent (for example, ethanol), and an aluminum chelating agent ( For example, an isopropanol solution of monoacetylacetonate bis (ethylacetoacetate) and, if necessary, a silanol compound of the formula (A) (for example, triphenylsilanol) is added, and it is several hours at a temperature of room temperature to about 50 ° C. The method of continuing stirring overnight can be mentioned.

  The thermosetting conductive paste composition of the present invention contains a conductive material. As the conductive material, a conventionally known conductive material can be used. For example, fine powders of graphite, silver, and copper can be used. The average particle diameter is preferably 0.01 to 50 μm, more preferably 0.1 to 20 μm. Examples of the shape of the particles include scaly, spherical, and irregular shapes, and these can be mixed and used as necessary.

  If the content of the conductive material in the thermosetting conductive paste composition is too small, sufficient conductivity cannot be ensured, and if it is too large, the amount of the resin component will be relatively reduced and sufficiently mixed. Is difficult, and the conductivity is lowered, so the content is preferably 60 to 95% by mass, more preferably 70 to 90% by mass.

  In addition to the silanol compound of formula (1), the thermosetting conductive paste composition of the present invention further contains a silane coupling agent, a filler such as silica and mica, a pigment, an antistatic agent, and the like. be able to.

  As described in paragraphs 0007 to 0010 of JP-A No. 2002-212537, the silane coupling agent is a cationic polymerization of a thermosetting resin (for example, a thermosetting epoxy resin) in cooperation with an aluminum chelating agent. Has the function of starting. Therefore, the effect of accelerating the curing of the epoxy resin can be obtained by using a small amount of such a silane coupling agent. As such a silane coupling agent, one having 1 to 3 lower alkoxy groups in the molecule, a group having reactivity to the functional group of the thermosetting resin in the molecule, for example, a vinyl group, It may have a styryl group, an acryloyloxy group, a methacryloyloxy group, an epoxy group, an amino group, a mercapto group, and the like. A coupling agent having an amino group or a mercapto group should be used when the latent curing agent of the present invention is a cationic curing agent, so that the amino group or mercapto group does not substantially trap the generated cationic species. Can do.

  Specific examples of such silane coupling agents include vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-styryltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ- Acryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β- (aminoethyl) ) -Γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercapto Propyltrimethoxy Examples include silane and γ-chloropropyltrimethoxysilane.

  When a small amount of silane coupling agent is used in combination, if the content is too small, the addition effect cannot be expected, and if it is too large, the effect of polymerization termination reaction due to silanolate anions generated from the silane coupling agent will occur. It is 1-300 mass parts with respect to 100 mass parts of chelate system latent hardening agents, Preferably it is 1-100 mass parts.

  The thermosetting conductive paste composition of the present invention comprises an aluminum chelate-based latent curing agent, a silanol compound of the formula (1), a glycidyl ether type epoxy resin and a conductive material, and optionally various additives according to a conventional method. It can be produced by uniformly mixing and stirring.

  The thus obtained thermosetting conductive paste composition of the present invention uses an aluminum chelate-based latent curing agent as a curing agent. Are better. In addition, although it contains a specific silanol that is highly sterically hindered despite containing a glycidyl ether epoxy resin that could not be sufficiently cured with an aluminum chelate latent curing agent, The curable conductive paste composition can be cationically polymerized by low temperature rapid curing.

  Hereinafter, the present invention will be specifically described.

Reference Example 1 (Production of aluminum chelate-based latent curing agent)
800 parts by mass of distilled water, 0.05 part by mass of a surfactant (Nurex RT, Nippon Oil & Fat Co., Ltd.), and 4 parts by mass of polyvinyl alcohol (PVA-205, Kuraray Co., Ltd.) as a dispersant. The mixture was placed in a 3 liter interfacial polymerization vessel equipped with a thermometer and mixed uniformly. In addition to this mixed solution, 100 parts by mass of a 24% isopropanol solution of aluminum monoacetylacetonate bis (ethylacetoacetate) (aluminum chelate D, Kawaken Fine Chemical Co., Ltd.), methylenediphenyl-4,4′-diisocyanate ( 3 mol) of trimethylolpropane (1 mol) adduct (D-109, Mitsui Chemicals, Inc.) 70 parts by mass, divinylbenzene (Merck) 30 parts by mass, radical polymerization initiator (Parroyl L, Nippon Oil & Fats) Company) 0.30 parts by mass of an oil phase solution dissolved in 100 parts by mass of ethyl acetate was added, and after emulsifying and mixing with a homogenizer (10000 rpm / 5 min), interfacial polymerization was carried out at 80 ° C. for 6 hours.

  After completion of the reaction, the polymerization reaction solution was allowed to cool to room temperature, and the interfacially polymerized particles were separated by filtration and air dried to obtain 100 parts by mass of a spherical aluminum chelate-based latent curing agent having a particle size of about 2 μm.

  100 parts by mass of the resulting aluminum chelate-based latent curing agent was mixed with 30 parts by mass (isopropyl alcohol 10) of 24% isopropanol solution of aluminum monoacetylacetonate bis (ethylacetoacetate) (Aluminum Chelate D, Kawaken Fine Chemicals Co., Ltd.) In a mixture with 60 parts by mass of ethanol) and stirred at 30 ° C. for 6 hours. After completion of the stirring, the curing agent particles were collected while washing with a nonpolar solvent (cyclohexane, toluene, etc.) and dried in vacuo at 30 ° C. for 24 hours.

Examples 1-2, Comparative Example 1
A thermosetting conductive paste composition was prepared by uniformly mixing a latent curing agent, a silanol compound, a bisphenol F-type epoxy resin, and a scaly silver powder according to the formulation shown in Table 1. Of the silanol compounds, triphenylsilanol was used that was dissolved in bisphenol F-type epoxy resin by heating at 80 ° C. for 2 hours.

Comparative Example 2
Instead of the aluminum chelate-based latent curing agent used in Example 1, aluminum tris (ethyl acetoacetate) (ALCH-TR, Kawaken Fine Chemical Co., Ltd.) was used as a curing agent that was not latentized. When the mixture was mixed in the same manner as in Example 1, the curing reaction started immediately after mixing, and no potential was recognized. For this reason, “viscosity”, “shearing adhesive strength”, and “volume resistivity” described later could not be measured.

(Evaluation)
For the thermosetting conductive paste compositions obtained in Examples 1 and 2 and Comparative Example 1, the following “viscosity”, “shearing adhesive strength” and “volume resistivity” were tested and evaluated.

<Viscosity>
The viscosity [Pa · s] of the obtained thermosetting conductive paste composition was measured with an E-type viscometer (1 ° cone plate, measurement temperature 25 ° C., rotation speed 0.5 rpm). The time of measurement is initially, after 24 hours at 40 ° C. and after 72 hours of standing. The obtained results are shown in Table 1. If the viscosity is too low, it may cause dripping at the time of application, and if it is too high, it tends to be difficult to apply. Therefore, it is preferable for practical use to be in the range of 20-30 Pa · s.

<Shear adhesive strength>
A 0.5 mm thick 6.3 mm square Si chip was bonded to SUS304 as follows. First, 15 mg of a thermosetting conductive paste composition was applied to the SUS surface, a Si chip was mounted thereon, a 50 g weight was placed on the Si chip and allowed to stand for 10 seconds, and then the weight was removed. Curing was performed under the prescribed conditions shown. Thereafter, the shear adhesive strength of the obtained cured product was measured with a die shear measuring device. In addition, the used thermosetting electrically conductive paste composition used what carried out the preservation | save process with the heating of leaving still at 40 degreeC for 72 hours, and the thing which did not carry out a preservation | save process. The obtained results are shown in Table 1. The shear adhesive force is preferably in the range of 30 to 250 kgf / chip for practical use.

<Volume resistivity>
The volume resistivity of the obtained thermosetting conductive paste composition was measured according to JIS K7194. In addition, the used thermosetting electrically conductive paste composition used what carried out the preservation | save process with the heating of leaving still at 40 degreeC for 72 hours, and the thing which did not carry out a preservation | save process. The obtained results are shown in Table 1. If the volume resistivity is too low, there is a tendency to induce corrosion of the conductive material or adherend contained in the paste due to a significant increase in conductivity, and if it is too high, the conductivity decreases, and the semiconductor chip and the lead frame Therefore, it is desirable that it is practically in the range of 1.0 × 10 ^{−2 to} 9.0 × 10 ⁻⁷ Ω · cm.

  From Table 1, the thermosetting conductive paste compositions of Examples 1 and 2 were compared with the thermosetting conductive paste composition of Comparative Example 1 for any evaluation items of viscosity, shear adhesive, and volume resistivity. It turns out that it is excellent in thermal stability.

<Low temperature fast curability>
Moreover, about the thermosetting electrically conductive paste composition of Example 1 and 2 and the comparative example 1, using the differential thermal analyzer (DSC6200, Seiko Instruments Inc.), the hardening characteristic (heat generation start temperature, heat generation peak) of a paste composition. Temperature, total calorific value). Here, the exothermic start temperature means a curing start temperature, and the exothermic peak temperature means a temperature at which curing is most active. The obtained results are shown in Table 2.

  From Table 2, it can be seen that the thermosetting conductive paste compositions of Examples 1 and 2 are superior to the thermosetting conductive paste composition of Comparative Example 1 in low-temperature quick curing properties.

  The thermosetting conductive paste composition of the present invention contains a silanol compound having a high steric hindrance property in addition to the aluminum chelate-based latent curing agent. For this reason, the polymerization termination reaction can be suppressed and the formation of a cation catalyst can be promoted. Therefore, the thermosetting conductive paste composition of the present invention is capable of rapid curing at low temperature, even though it contains a glycidyl ether type epoxy resin that has not been sufficiently polymerized with an aluminum chelate-based latent curing agent. In addition, the storage stability is excellent. Therefore, it is useful when the semiconductor chip is bonded and fixed to a lead frame or the like.

Claims (8)

An aluminum chelate-based latent curing agent obtained by holding an aluminum chelating agent in a porous resin obtained by interfacially polymerizing a polyfunctional isocyanate compound and radically polymerizing a radically polymerizable monomer; and a silanol compound of the formula (A): , A thermosetting conductive paste composition containing a glycidyl ether type epoxy resin and a conductive material, wherein the content ratio of the silanol compound to the total of the silanol compound and the glycidyl ether type epoxy resin is 5 to 30% by mass. A thermosetting conductive paste composition.

(In the formula, m is 2 or 3, provided that the sum of m and n is 4. Ar is halogen, trifluoromethyl, nitro, sulfo, carboxyl, alkoxycarbonyl, formyl, alkyl, alkoxy, hydroxy, A phenyl group, a naphthyl group, an anthracenyl group, an azulenyl group, a fluorenyl group, a thienyl group, a furyl group, a pyrrolyl group, an imidazolyl group, which may have 1 to 3 substituents selected from amino, monoalkylamino or dialkylamino; An aryl group selected from pyridyl groups.)   The thermosetting conductive paste composition according to claim 1, wherein Ar is a phenyl group.   The thermosetting conductive paste composition according to claim 1 or 2, wherein the silanol compound is triphenylsilanol or diphenylsilanol.   The thermosetting conductive paste composition according to any one of claims 1 to 3, wherein the glycidyl ether type epoxy resin is a bisphenol F type epoxy resin.   Furthermore, the thermosetting electrically conductive paste composition in any one of Claims 1-4 containing an oxetane compound and / or an alicyclic epoxy compound. La radical polymerizable monomer, thermosetting conductive paste composition according to any one of claims 1 to 5 is di Binirubenze down. The aluminum chelate type latent curing agent is further thermosetting conductive paste composition of claim 6 Symbol mounting impregnation treatment is applied to the aluminum chelating agent. Semiconductor chip, the semiconductor device comprising fixedly connected to the lead frame by thermosetting conductive paste composition according to any one of claims 1-7.