Paste composition, semiconductor device and method for manufacturing same, and electronic component and method for manufacturing same

Abstract

This paste composition contains silver particles (A) and a binder (B), wherein the content of silver particles (A1) having a particle diameter of more than 20 μm in 100 mass% of the silver particles (A) is 5 mass% or less, the content of the silver particles (A) in 100 mass% of the total amount of the silver particles (A) and the binder (B) is 95 mass% or more, and the rate of change represented by formula (1) is 250% or more.　Formula (1): rate of change = (S1 - S0) / S0 × 100(%) [S0 is the crystallite diameter of the silver particles in the dried product of the paste composition in the Miller index (111).　S1 is the crystallite diameter of the silver particles in a processed product, obtained by heat-pressurizing a dried product of the paste composition at 15 MPa and 200°C for 2 minutes in a nitrogen atmosphere, in the Miller index (111).]

Description

Paste composition, semiconductor device and manufacturing method thereof, and electronic component and manufacturing method thereof

[0001] The present disclosure relates to a paste composition, a semiconductor device and a method for manufacturing the same, and an electronic component and a method for manufacturing the same.

[0002] In recent years, there has been active development of power semiconductor devices using wide bandgap semiconductor elements, such as silicon carbide (SiC) and gallium nitride (GaN), which have low power loss. In these power semiconductor devices, the wide bandgap semiconductor elements are bonded to other components, such as a semiconductor support member, by a bonding member formed from a bonding material. These wide bandgap semiconductor elements possess high heat resistance and are capable of high-temperature operation at 250°C or higher due to large currents. These characteristics are achieved by sufficient heat dissipation of heat generated by the elements during operation. Therefore, there is a demand for bonding materials that have excellent long-term high-temperature resistance in addition to electrical conductivity and heat transfer.

[0003] Sintered materials are increasingly being used as joining materials. Sintered materials are paste compositions containing fine metal particles. These fine metal particles are sintered at temperatures significantly lower than the melting point of the metal itself, and after sintering, they can acquire thermal conductivity and heat resistance equivalent to that of bulk metal.

[0004] Sintered materials are classified into pressureless and pressureless types based on the bonding process. Pressureless types involve heating but not pressure during bonding. Pressureless types involve both heating and pressure during bonding. Among these, pressureless types are used in fields requiring high connection reliability, such as automotive applications (e.g., on-board inverters). This is because high connection reliability can be achieved by forming a dense sintered body through pressure during bonding. Conventional pressureless types typically require heating to temperatures above 250°C during bonding. However, there are concerns about damage to surrounding components due to high temperatures and reduced connection reliability due to residual stress resulting from thermal expansion. Therefore, pressureless sintered materials that can be bonded at low temperatures are needed. For example, Patent Document 1 describes a technology that focuses on the change in crystallite size before and after heat treatment and performs pressure bonding at a low bonding temperature of 200°C.

[0005] Japanese Patent Application Laid-Open No. 2020-136580

[0006] The present disclosure relates to the following [1] to

[11] .

[0007] [1] A paste composition comprising silver particles (A) and a binder (B), wherein the content of silver particles (A1) having a particle diameter of more than 20 μm is 5% by mass or less relative to 100% by mass of the silver particles (A), the content of the silver particles (A) is 95% by mass or more relative to 100% by mass of the total amount of the silver particles (A) and the binder (B), and the rate of change expressed by the following formula (1) is 250% or more: Rate of change = (S1 - S0) / S0 × 100 (%) ... (1) [S0 is the Miller index (111) crystallite diameter of the silver particles in a dried product of the paste composition. S1 is the Miller index (111) crystallite diameter of the silver particles in a treated product obtained by heating and pressurizing the dried product of the paste composition under a nitrogen atmosphere at 15 MPa and 200°C for 2 minutes. [2] The paste composition according to the above item [1], wherein the content of silver particles (A2) having a particle diameter of 1.0 to 20 μm is 50% by mass or less, based on 100% by mass of the silver particles (A). [3] The paste composition according to the above item [1] or [2], wherein the content of silver particles (A3) having a particle diameter of less than 1.0 μm is 50% by mass or more, based on 100% by mass of the silver particles (A). [4] The silver particles (A) have a specific surface area of ​​1.4 m or less. ２ / g or more. [5] The paste composition according to any of [1] to [3] above, wherein the binder (B) comprises one or more resins selected from a thermosetting resin and a thermoplastic resin. [6] The paste composition according to any of [1] to [5] above, wherein the binder (B) has a 5% weight loss temperature of 250°C or more. [7] The paste composition according to any of [1] to [6] above, wherein the binder (B) has a 5% weight loss temperature of 250°C or more. [8] The paste composition according to any of [1] to [6] above, wherein the binder (B) comprises a solvent (C), and the content of the solvent (C) is 10 to 30% by mass relative to 100% by mass of the total amount of the silver particles (A), the binder (B), and the solvent (C). [8] A semiconductor device having a bond formed from the paste composition according to any of [1] to [7] above. [9] A method for manufacturing a semiconductor device including a semiconductor element and a semiconductor support member, comprising the steps of applying the paste composition according to any one of [1] to [7] above to the semiconductor support member, mounting the semiconductor element on the paste composition, and heat-pressure bonding the semiconductor element and the semiconductor support member, wherein the heat-pressure bonding conditions are 180 to 300°C, 1 to 30 MPa, and 0.5 to 10 minutes.

[10] An electronic component having a bonded portion formed using the paste composition according to any one of [1] to [7] above.

[11] A method for manufacturing an electronic component, comprising the step of forming a bonded portion using the paste composition according to any one of [1] to [7] above.

[0008] The bonding method described in Patent Document 1 has a threshold adhesive strength of 20 MPa, which is an evaluation standard for sinterability, and is therefore difficult to say that it has sufficient bonding properties. The present disclosure aims to provide a paste composition that has high applicability and can achieve high adhesive strength through heat-pressure bonding at low temperatures, resulting in bonding that is resistant to delamination due to thermal cycles, as well as a semiconductor device and a method for manufacturing the same, and an electronic component and a method for manufacturing the same, using the paste composition. The inventors have focused on the change in crystallite size of silver particles during heat-pressure bonding and have found that by selecting silver particles with good sinterability during the pressurization process, it is possible to provide a paste composition that has high applicability and can achieve high adhesive strength through heat-pressure bonding at low temperatures, resulting in bonding that is resistant to delamination due to thermal cycles, as well as a semiconductor device and a method for manufacturing the same, and an electronic component and a method for manufacturing the same, using the paste composition. According to the present disclosure, it is possible to provide a paste composition that has high applicability and can achieve high adhesive strength through heat-pressure bonding at low temperatures, resulting in bonding that is resistant to delamination due to thermal cycles, as well as a semiconductor device and a method for manufacturing the same, and an electronic component and a method for manufacturing the same, using the paste composition.

[0009] Hereinafter, embodiments of the present disclosure will be described in detail. In the following description, the notation "A to B" indicating a numerical range means "A or more and B or less," including the endpoints, and when it is stated that "may be A to B, may be C to D, or may be E to F," the upper and lower limits can be combined arbitrarily. Furthermore, in the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples.

[0010] [Paste Composition] The paste composition of the present disclosure comprises silver particles (A) and a binder (B), wherein the content of silver particles (A1) having a particle diameter of more than 20 μm is 5% by mass or less relative to 100% by mass of the silver particles (A), the content of the silver particles (A) is 95% by mass or more relative to 100% by mass of the total amount of the silver particles (A) and the binder (B), and the rate of change expressed by the following formula (1) is 250% or more: Rate of change = (S1 - S0) / S0 × 100 (%) (1) Here, S0 is the Miller index (111) crystallite diameter of the silver particles in a dried product of the paste composition. S1 is the Miller index (111) crystallite diameter of the silver particles in a treated product obtained by heating and pressurizing the dried product of the paste composition under a nitrogen atmosphere at 15 MPa and 200°C for 2 minutes.

[0011] The paste composition of the present disclosure has good coatability, can be pressure-bonded at low temperatures, and has high adhesive strength. While the details of the reasons for this are unclear, it is presumed to be as follows. Specifically, crystal growth occurs both within the particles and through sintering between particles. It is believed that the greater the degree of crystal growth, the greater the degree of sintering. Generally, the smaller the crystallite diameter, the easier the crystals grow, but the degree of crystal growth is thought to vary depending on the particle shape, size, and treatment conditions. Silver particles with a large rate of change in crystallite diameter due to treatment simulating a bonding step (heating and pressurizing at 15 MPa and 200°C for 2 minutes in a nitrogen atmosphere) tend to pack closely together under these conditions, resulting in high contact frequency, and therefore sintering. That is, if the rate of change {((S1-S0) / S0) × 100} of silver particles (A) is 250% or more, they can exhibit good sinterability during heat and pressure treatment at low temperatures. Furthermore, as described above, silver particles (A) exhibit good sinterability during heat and pressure treatment at low temperatures, resulting in high bonding performance. Therefore, the content of the binder (B) contained for bonding can be reduced. That is, in the paste composition of the present disclosure, the content of silver particles (A) is 95% by mass or more relative to 100% by mass of the total amount of silver particles (A) and binder (B). As described above, the paste composition of the present disclosure has a high content of silver particles (A), and therefore can form a bonded portion that has high bonding strength, high thermal conductivity, and high electrical conductivity.

[0012] <Silver Particles (A)> The silver particles (A) have a rate of change, represented by the following formula (1), of 250% or more: Rate of change = (S1 - S0) / S0 × 100 (%) (1) Here, S0 is the Miller index (111) crystallite diameter of the silver particles in a dried product of the paste composition. Furthermore, S1 is the Miller index (111) crystallite diameter of the silver particles in a treated product obtained by heating and pressurizing the dried paste composition in a nitrogen atmosphere at 15 MPa and 200°C for 2 minutes.

[0013] When the rate of change {((S1-S0) / S0) x 100} is 250% or more, it is possible to obtain a paste composition that can achieve bonding with high adhesive strength and resistance to peeling due to thermal cycles when heated and pressurized at low temperatures. There is no particular upper limit to the rate of change {((S1-S0) / S0) x 100}, but from the viewpoint of reducing structural changes in the sintered layer due to thermal history after bonding, it may be 500% or less. From this viewpoint, the rate of change {((S1-S0) / S0) x 100} may be 255 to 475%, 270 to 450%, 285 to 425%, or 300 to 400%.

[0014] The crystallite diameter S0 of the silver particles (A) may be 30 to 70 nm. Within this range, crystals tend to grow easily during heating and pressurization, facilitating sintering. From this perspective, the crystallite diameter S0 may be 40 to 60 nm. The crystallite diameter S0 can be measured as follows. The silver particles (A) in the dried paste composition are pressed into a cake. The crystallite diameter S0 can be calculated by applying the cake to a glass plate and using an X-ray diffractometer with a CuKα ray source by a focusing method, using the Scherrer equation for the Miller index (111) plane peak. Specifically, it can be obtained by the method described in the Examples.

[0015] The silver particles (A) may have a crystallite diameter S1 of 105 to 420 nm. A crystallite diameter S1 of 105 nm or more can reduce structural changes in the sintered layer after bonding. A crystallite diameter S1 of 420 nm or less can reduce stress generated inside the sintered layer. From this perspective, the crystallite diameter S1 may be 120 to 400 nm, 130 to 350 nm, or 140 to 300 nm. The crystallite diameter S1 can be measured as follows. The silver particles (A) in the dried paste composition are compressed into a cake. A sintered body is obtained by heating the cake to 200°C at a heating rate of 60°C / min under a pressure of 15 MPa in a nitrogen atmosphere, heating and pressurizing the cake at 15 MPa and 200°C for 2 minutes, and then cooling the cake to room temperature (25°C) at a heating rate of 110°C / min. A powder is obtained by pulverizing the sintered body in a mortar. The crystallite size S1 can be calculated by applying the powder to a glass plate, and then using an X-ray diffractometer with a CuKα ray source, using the Scherrer formula for the Miller index (111) plane peak, by a focusing method. Specifically, it can be obtained by the method described in the Examples.

[0016] The rate of change {((S1-S0) / S0) × 100} tends to be improved by, for example, setting the particle size of silver particles (A) within the ranges described below and setting the crystallite size S0 of silver particles (A) within the ranges described below. The rate of change {((S1-S0) / S0) × 100} of silver particles can be easily measured using the method for measuring S0 and S1 described above.

[0017] The average particle size of the silver particles (A) may be 0.62 to 5.0 μm. When the average particle size is 0.62 μm or more, the silver particles come into contact with each other more frequently during pressure application, improving sinterability. When the average particle size is 5.0 μm or less, damage to semiconductor elements or substrates during pressure application can be reduced. Furthermore, when the average particle size of the silver particles (A) is 0.62 to 5.0 μm, the aforementioned rate of change {((S1-S0) / S0)×100} tends to be high. From this viewpoint, the average particle size of the silver particles (A) may be 0.65 to 3.0 μm, or may be 2.0 μm or less, or may be 1.75 μm or less.

[0018] The shape of the silver particles (A) is not particularly limited, and examples thereof include spherical and flake shapes. The shape of the silver particles (A) may be spherical. The silver particles (A) may be primary particles or secondary particles formed by aggregation of primary particles. The silver particles (A) may be hollow or solid particles, but may be hollow particles from the viewpoint of low-temperature sintering properties. Here, hollow particles refer to particles having voids inside the particles. When the silver particles (A) are hollow particles, voids may be present in the center of the silver particles. Furthermore, solid particles refer to particles having substantially no space inside the particles.

[0019] The specific surface area of ​​silver particles (A) measured by the BET method is 1.4 m ２ The specific surface area may be 1.4 m / g or more. ２ When the specific surface area is 2.0 m / g or more, the contact between silver particles can be increased, and the proportion of highly active silver atoms on the particle surface can be increased. ２ / g or less. ２ When the specific surface area is 1.5 to 1.95 m / g or less, the viscosity of the paste composition can be reduced and aggregation of silver particles can be reduced. ２ The specific surface area of ​​silver particles (A) can be measured by a BET single-point method using nitrogen adsorption using a specific surface area measurement device, and specifically, can be measured by the method described in the Examples.

[0020] The content of the silver particles (A) in 100% by mass of the total amount of the silver particles (A) and the binder (B) is 95% by mass or more. When the content is 95% by mass or more, a paste composition can be obtained that can achieve high adhesive strength and resist peeling due to thermal cycling when subjected to heat and pressure bonding at low temperatures. Furthermore, the content of the silver particles (A) in 100% by mass of the total amount of the silver particles (A) and the binder (B) may be 99% by mass or less. When the content is 99% by mass or less, the function of the binder (B) is fully exhibited, resulting in a paste composition that has high coatability and can reduce structural changes in the sintered layer due to thermal history after bonding. From this viewpoint, the content may be 95 to 99% by mass, 95.5 to 98.7% by mass, or 96 to 98.5% by mass.

[0021] From the viewpoint of sinterability, the silver content in the paste composition, relative to the total amount of metals present in the paste composition (100% by mass), may be 60% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or 99% by mass or more, and the paste composition may not contain any metals other than silver.

[0022] <<Silver Particles (A1)>> In the present disclosure, the content of silver particles (A1) having a particle diameter of more than 20 μm is 5% by mass or less relative to 100% by mass of silver particles (A). The content of the silver particles (A1) may be 0% by mass. When the content is 5% by mass or less, no squeegee marks are left during printing application, and a pressure load can be uniformly applied to the bonding layer. Therefore, when the content is 5% by mass or less, a paste composition can be obtained that has high coatability and can perform bonding by heating and pressurizing at low temperatures, with high adhesive strength and resistance to peeling due to thermal cycling. From this perspective, the content may be 2.5% by mass or less, 1.5% by mass or less, or 1.0% by mass or less.

[0023] <<Silver Particles (A2)>> The content of silver particles (A2) having a particle size of 1.0 to 20 μm in 100% by mass of silver particles (A) of the present disclosure may be 50% by mass or less. When the content is 50% by mass or less, a uniform silver sintered layer can be formed. Furthermore, the content may be 5% by mass or more. When the content is 5% by mass or more, the frequency of contact between silver particles can be improved. From this viewpoint, the content may be 8 to 45% by mass, 10 to 40% by mass, or 15 to 36% by mass.

[0024] <<Silver Particles (A3)>> The content of silver particles (A3) having a particle diameter of less than 1.0 μm relative to 100% by mass of silver particles (A) of the present disclosure may be 50% by mass or more. When the content is 50% by mass or more, a uniform silver sintered layer can be formed. Furthermore, the content may be 95% by mass or less. When the content is 95% by mass or less, the frequency of contact between silver particles can be improved. From this viewpoint, the content may be 55 to 92% by mass, 60 to 90% by mass, or 64 to 85% by mass.

[0025] (Method for Producing Silver Particles (A)) The method for producing silver particles (A) comprises the steps of adding aqueous ammonia to an aqueous solution containing a silver compound to obtain a silver ammine complex solution, and reducing the silver ammine complex in the silver ammine complex solution obtained in the above step with a reducing compound to obtain a silver particle-containing slurry.

[0026] (Step of Obtaining a Silver Ammine Complex Solution) In this step, ammonia water is added to an aqueous solution containing a silver compound to obtain a silver ammine complex solution. Examples of the silver compound include silver nitrate, silver chloride, silver acetate, silver oxalate, and silver oxide. From the viewpoint of solubility in water, the silver compound may be silver nitrate or silver acetate.

[0027] The amount of ammonia added may be 2 to 50 mol, 5 mol or more, or 10 mol or more per mol of silver in the aqueous solution containing the silver compound. When the amount of ammonia added is within the above range, the average particle size of the primary particles can be set within the above range.

[0028] (Step of Obtaining Silver Particle-Containing Slurry) In this step, the silver ammine complex in the silver ammine complex solution obtained in the previous step is reduced with a reducing compound to obtain a silver particle-containing slurry. By reducing the silver ammine complex with the reducing compound, the primary particles of the silver particles in the silver ammine complex aggregate to form secondary particles (hollow particles) with a void in the center.

[0029] By appropriately adjusting the amount of silver in the silver ammine complex and the content of the reducing compound, it is possible to control the aggregation of the primary particles and to set the average particle size of the resulting secondary particles within the above-mentioned range.

[0030] The reducing compound is not particularly limited as long as it has the reducing power to reduce the silver ammine complex and precipitate silver. Examples of the reducing compound include hydrazine derivatives. Examples of hydrazine derivatives include hydrazine monohydrate, methylhydrazine, ethylhydrazine, n-propylhydrazine, i-propylhydrazine, n-butylhydrazine, i-butylhydrazine, sec-butylhydrazine, t-butylhydrazine, n-pentylhydrazine, i-pentylhydrazine, neo-pentylhydrazine, t-pentylhydrazine, n-hexylhydrazine, i-hexylhydrazine, n-heptylhydrazine, n-octylhydrazine, n-nonylhydrazine, n-decylhydrazine, n-undecylhydrazine, n-dodecylhydrazine, cyclohexylhydrazine, phenylhydrazine, 4-methylphenylhydrazine, benzylhydrazine, 2-phenylethylhydrazine, 2-hydrazinoethanol, acetohydrazine, etc. These may be used alone or in combination of two or more.

[0031] The content of the reducing compound may be 0.25 to 20.0 mol per mol of silver in the silver ammine complex, or may be 10.0 mol or less, or may be 5.0 mol or less. When the content of the reducing compound is within the above range, the average particle size of the obtained secondary particles can be within the above range.

[0032] Furthermore, the temperature of the silver ammine complex solution during the reduction of the silver ammine complex may be less than 30° C. or may be 0 to 20° C. If the temperature of the silver ammine complex solution is within this range, it is possible to control the aggregation of the primary particles and to keep the average particle size of the resulting secondary particles within the above-mentioned range.

[0033] <Binder (B)> The binder (B) may contain one or more resins selected from thermosetting resins and thermoplastic resins.

[0034] <<Thermosetting Resin>> The thermosetting resin can be any thermosetting resin that is generally used for adhesive applications, without any particular limitation. The thermosetting resin may be a resin that is liquid at room temperature (25°C), or a resin that becomes a paste when diluted with a solvent or the like. The thermosetting resin may include at least one selected from cyanate resins, epoxy resins, acrylic resins, and maleimide resins. These may be used alone, or two or more may be used in combination.

[0035] Cyanate resins are compounds having an -NCO group in the molecule, and the -NCO group reacts upon heating. Specific examples include 1,3-dicyanatobenzene, 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, 1,3-dicyanatonaphthalene, 1,4-dicyanatonaphthalene, 1,6-dicyanatonaphthalene, 1,8-dicyanatonaphthalene, 2,6-dicyanatonaphthalene, 2,7-dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 4,4'-dicyanatobiphenyl, bis(4-cyanatophenyl)methane, bis(3,5-dimethyl-4-cyanatophenyl)methane, and bis(4,4'-dicyanatobiphenyl). Examples of suitable cyanates include 2,2-bis(4-cyanatophenyl)methane, 2,2-bis(4-cyanatophenyl)propane, 2,2-bis(3,5-dibromo-4-cyanatophenyl)propane, bis(4-cyanatophenyl)ether, bis(4-cyanatophenyl)thioether, bis(4-cyanatophenyl)sulfone, tris(4-cyanatophenyl)phosphite, tris(4-cyanatophenyl)phosphate, and cyanates obtained by reacting a novolak resin with a cyanogen halide. Prepolymers having a triazine ring formed by trimerizing the cyanate groups of these polyfunctional cyanate resins can also be used. Such prepolymers can be obtained by polymerizing the above-mentioned polyfunctional cyanate resin monomers using, for example, an acid such as a mineral acid or a Lewis acid, a base such as a sodium alcoholate or a tertiary amine, or a salt such as sodium carbonate as a catalyst.

[0036] As the curing accelerator for the cyanate resin, generally known ones can be used. Examples include, but are not limited to, organometallic complexes such as zinc octoate, tin octoate, cobalt naphthenate, zinc naphthenate, and iron acetylacetonate; metal salts such as aluminum chloride, tin chloride, and zinc chloride; and amines such as triethylamine and dimethylbenzylamine. These curing accelerators can be used alone or in combination of two or more.

[0037] Epoxy resins are compounds having one or more glycidyl groups in the molecule, and the glycidyl groups react upon heating. The epoxy resins may be compounds having two or more glycidyl groups in one molecule. Examples include, but are not limited to, bifunctional epoxy compounds obtained by epoxidizing bisphenol compounds such as bisphenol A, bisphenol F, and biphenol, or derivatives thereof; diols having an alicyclic structure such as cyclohexanediol, cyclohexanedimethanol, and cyclohexanediethanol, or derivatives thereof; aliphatic diols such as butanediol, hexanediol, octanediol, nonanediol, and decanediol, or derivatives thereof; trifunctional epoxy compounds obtained by epoxidizing compounds having a trihydroxyphenylmethane skeleton or an aminophenol skeleton; and polyfunctional epoxy compounds such as phenol novolac resins, cresol novolac resins, phenol aralkyl resins, biphenyl aralkyl resins, naphthol aralkyl resins, and polybutadiene. The epoxy resins may be liquid at room temperature (25°C) either alone or as a mixture. A compound containing one glycidyl group per molecule can also be used as a commonly used reactive diluent. Examples of reactive diluents include monofunctional aromatic glycidyl ethers such as phenyl glycidyl ether and cresyl glycidyl ether, and aliphatic glycidyl ethers.

[0038] Examples of epoxy resin curing agents include aliphatic amines, aromatic amines, dicyandiamide, dihydrazide compounds, acid anhydrides, phenolic resins, and organic peroxides. Examples of dihydrazide compounds include carboxylic acid dihydrazides such as adipic acid dihydrazide, dodecanoic acid dihydrazide, isophthalic acid dihydrazide, and p-oxybenzoic acid dihydrazide. Examples of acid anhydrides include phthalic acid anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, dodecenylsuccinic anhydride, a reaction product of maleic anhydride and polybutadiene, and a copolymer of maleic anhydride and styrene. Examples of organic peroxides include hydroperoxides, dialkyl peroxides, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide, acetyl peroxide, acyl peroxide, cumene peroxide, peroxyketals such as 1,1-di-t-butylperoxycyclohexane, and peroxyesters such as t-butyl peroxybenzoate, as well as so-called room temperature curing organic peroxides such as methyl ethyl ketone peroxide.

[0039] Furthermore, a curing accelerator can be blended to accelerate curing. Examples of the curing accelerator for epoxy resins include imidazoles, triphenylphosphine or tetraphenylphosphine and their salts, and amine compounds such as diazabicycloundecene and their salts. Examples of the curing accelerator include 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-C １１ H ２３ The compound may be an imidazole compound such as 2-imidazole, an adduct of 2-methylimidazole and 2,4-diamino-6-vinyltriazine, etc. The compound may be an imidazole compound having a melting point of 180° C. or higher.

[0040] Examples of acrylic resins include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 1,2-cyclohexanediol mono(meth)acrylate, 1,3-cyclohexanediol mono(meth)acrylate, 1,4-cyclohexanediol mono(meth)acrylate, 1,2-cyclohexanedimethanol mono(meth)acrylate, 1,3-cyclohexanedimethanol mono(meth)acrylate, 1,4-cyclohexanedimethanol mono(meth)acrylate, 1,2-cyclohexanediethanol mono(meth)acrylate, Examples of the hydroxyl group-containing (meth)acrylate include (meth)acrylates having a hydroxyl group such as methylpropane mono(meth)acrylate, 1,3-cyclohexanediethanol mono(meth)acrylate, 1,4-cyclohexanediethanol mono(meth)acrylate, glycerin mono(meth)acrylate, glycerin di(meth)acrylate, trimethylolpropane mono(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol mono(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, and neopentyl glycol mono(meth)acrylate, as well as (meth)acrylates having a carboxyl group obtained by reacting these hydroxyl group-containing (meth)acrylates with dicarboxylic acid or a derivative thereof. Examples of dicarboxylic acids that can be used herein include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, and derivatives thereof.

[0041] Examples of acrylic resins include polyethers, polyesters, polycarbonates, and poly(meth)acrylates having a molecular weight of 100 to 10,000, which are compounds having a (meth)acrylic group; (meth)acrylates having a hydroxy group; and (meth)acrylamides having a hydroxy group.

[0042] A maleimide resin is a compound containing one or more maleimide groups per molecule, and the maleimide groups react upon heating. Examples of maleimide resins include bismaleimide resins such as N,N'-(4,4'-diphenylmethane)bismaleimide, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, and 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane. The maleimide resin may be a compound obtained by reacting a dimer acid diamine with maleic anhydride; or a compound obtained by reacting a maleimidized amino acid, such as maleimidoacetic acid or maleimidocaproic acid, with a polyol. The maleimidized amino acid may be obtained by reacting maleic anhydride with aminoacetic acid or aminocaproic acid. The polyol may be a polyether polyol, polyester polyol, polycarbonate polyol, or poly(meth)acrylate polyol, and may not contain an aromatic ring.

[0043] <<Thermoplastic Resin>> The thermoplastic resin can be any thermoplastic resin that is generally used for adhesive applications, without any particular limitation. Examples include acrylic resins, methacrylic resins, vinyl resins, carbonate resins, cellulose, polyolefin resins, ethylene-vinyl acetate copolymers, and polyamide resins. It is sufficient to include at least one selected from the thermoplastic resins exemplified above. These may be used alone, or two or more may be used in combination.

[0044] The content of the binder (B) is 5.0% by mass or less based on 100% by mass of the total amount of the silver particles (A) and the binder (B). When the content is 5.0% by mass or less, it is possible to fill the voids in the structure formed by silver sintering without inhibiting the sintering of the silver particles. The content of the binder (B) may be 0.1% by mass or more based on 100% by mass of the total amount of the silver particles (A) and the binder (B). When the content is 0.1% by mass or more, the resin fills the voids in the structure formed by silver sintering, thereby alleviating stress applied to the sintered layer. From this viewpoint, the content may be 0.1 to 5.0% by mass, 0.5 to 4.8% by mass, 1.0 to 4.5% by mass, or 1.5 to 4.0% by mass.

[0045] <<Physical Properties, etc.>> The 5% weight loss temperature of the binder (B) may be 250°C or higher. A temperature of 250°C or higher can reduce thermal decomposition of the resin during bonding. There is no particular upper limit to the 5% weight loss temperature of the binder (B), but it may be 450°C or lower from the viewpoints of binder availability, compatibility with solvents, and the like. From this viewpoint, the 5% weight loss temperature of the binder (B) may be 250 to 450°C, 300 to 425°C, or 350 to 400°C. The 5% weight loss temperature of the binder (B) can be measured using a thermogravimetric and differential scanning calorimeter, specifically, by the method described in the examples.

[0046] <Solvent (C)> From the viewpoint of workability, the paste composition of the present disclosure may further contain a solvent (C). Examples of the solvent (C) include butyl carbitol, cellosolve acetate, ethyl cellosolve, butyl cellosolve, butyl cellosolve acetate, butyl carbitol acetate, diethylene glycol dimethyl ether, diacetone alcohol, N-methyl-2-pyrrolidone (NMP), dimethylformamide, N,N-dimethylacetamide (DMAc), γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, 3,5-dimethyl-1-adamantanamine (DMA), and terpene ethers such as dihydroterpinyloxyethanol. These may be used alone or in combination of two or more.

[0047] When the paste composition of the present disclosure contains a solvent (C), the content of the solvent (C) in 100% by mass of the paste composition may be 5 to 50% by mass. A content of 5% by mass or more can impart good coatability. A content of 50% by mass or less can reduce settling of silver particles when the paste composition is allowed to stand, thereby improving the usable time. From this viewpoint, the content may be 10 to 40% by mass, 12 to 30% by mass, or 15 to 25% by mass.

[0048] When the paste composition of the present disclosure contains a solvent (C), the content of the solvent (C) may be 10 to 30% by mass relative to 100% by mass of the total amount of the silver particles (A), the binder (B), and the solvent (C). A content of 10% by mass or more can impart good coatability. A content of 30% by mass or less can reduce settling of silver particles when the paste composition is allowed to stand, thereby improving the usable time. From this viewpoint, the content may be 12 to 25% by mass.

[0049] <Other Components> In addition to the above components, the paste composition of the present disclosure may contain, as needed, stress-reducing agents such as rubber and silicone, coupling agents, antifoaming agents, surfactants, colorants such as pigments and dyes, various polymerization inhibitors, antioxidants, solvents, fluxing agents, and other various additives that are generally blended into this type of composition. Each of these additives may be used alone, or two or more may be mixed and used. The paste composition of the present disclosure may or may not contain a resin containing an aromatic amine skeleton.

[0050] The total content of silver particles (A), binder (B), and solvent (C) in 100% by mass of the paste composition of the present disclosure may be 80 to 100% by mass, 90 to 99.95% by mass, or 95 to 99.9% by mass. The total content of silver particles (A) and binder (B) in 100% by mass of the solid content of the paste composition of the present disclosure may be 80 to 100% by mass, 90 to 100% by mass, or 95 to 99.9% by mass. Here, the solid content refers to the components of the paste composition excluding solvent (C).

[0051] The paste composition of the present disclosure can be prepared by thoroughly mixing the above-described silver particles (A), binder (B), optionally containing a solvent (C), and various additives, followed by further kneading using a disperse mill, a kneader, a three-roll mill, or the like, and then degassing the mixture.

[0052] <Physical Properties of Paste Composition> (Viscosity) From the viewpoint of coatability, the viscosity of the paste composition of the present disclosure may be 1 to 200 Pa·s, 10 to 100 Pa·s, 12 to 50 Pa·s, or 15 to 25 Pa·s. The viscosity is a value measured using an E-type viscometer (3° cone) at 25°C and a rotation speed of 2.0 rpm. Specifically, the viscosity can be measured by the method described in the examples.

[0053] (Thixitropy Index) From the viewpoint of coatability, the thixotropy index of the paste composition of the present disclosure may be 1 to 20, 2 to 10, or 3.5 to 7. The thixotropy index is determined by measuring the viscosity (V) at a temperature of 25°C and a rotation speed of 2.0 rpm using an E-type viscometer (3°C). ２．０ ) and viscosity at 20 rpm (V ２０ ) and measure the viscosity ratio (V ２．０ / V ２０ Specifically, it can be measured by the method described in the Examples.

[0054] (Shear Strength) The shear strength of the cured product of the paste composition of the present disclosure may be 80 MPa or more. When the shear strength is 80 MPa or more, bonding can be performed by heating and pressurizing at low temperatures, resulting in high adhesive strength and resistance to peeling due to thermal cycling. From this perspective, the shear strength of the cured product of the paste composition may be 85 MPa or more, 90 MPa or more, or even 92 MPa or more. The shear strength of the cured product of the paste composition can be measured by applying the paste composition to a copper frame, mounting a backside gold chip with a gold vapor deposition layer on the 2 mm x 2 mm bonding surface, and performing heating and pressurizing curing at 200°C and 15 MPa for 2 minutes, followed by measuring the hot die shear strength at 260°C using a mount strength measuring device. Specifically, it can be measured by the method described in the Examples.

[0055] (Volume Resistivity) The volume resistivity of the cured product of the paste composition of the present disclosure may be 4.0 μΩ·cm or less. When the volume resistivity is 4.0 μΩ·cm or less, resistance heating at the joint can be reduced. From this viewpoint, the volume resistivity of the cured product of the paste composition may be 3.5 μΩ·cm or less, 3.4 μΩ·cm or less, or even 3.0 μΩ·cm or less. The volume resistivity of the cured product of the paste composition can be measured by applying the paste composition to a thickness of 30 μm on a glass substrate, drying it, and curing it at 200°C and 15 MPa for 2 minutes to obtain wiring, and measuring the electrical resistivity using a resistivity meter with a four-terminal method. Specifically, the measurement can be performed by the method described in the examples.

[0056] [Semiconductor device and manufacturing method thereof] The semiconductor device of the present disclosure has a joint formed from the paste composition described above. Because the semiconductor device of the present disclosure has a joint formed from the paste composition described above, it has good heat dissipation properties and connection reliability, and can provide a semiconductor device for an on-vehicle component. The semiconductor device may have a semiconductor element, a substrate, and a joint that joins the semiconductor element and the substrate. The joint is formed from the paste composition described above.

[0057] The method for manufacturing a semiconductor device according to the present disclosure is a method for manufacturing a semiconductor device including a semiconductor element and a semiconductor support member, and includes the steps of applying the paste composition to the semiconductor support member, mounting the semiconductor element on the paste composition, and bonding the semiconductor element and the semiconductor support member together under heat and pressure, wherein the heat and pressure bonding is performed under conditions of 180 to 300°C and 1 to 30 MPa for 0.5 to 10 minutes.

[0058] When the heating temperature in the heat and pressure bonding is 180°C or higher, sintering proceeds sufficiently, improving the bonding strength of the bonded portion. When the heating temperature is 300°C or lower, thermal deterioration of members such as the semiconductor element and the semiconductor support member is reduced. From this viewpoint, the heating temperature may be 180 to 300°C, 185 to 250°C, or 190 to 210°C.

[0059] When the pressure during the heat and pressure bonding is 1 MPa or more, sintering proceeds sufficiently, improving the bonding strength of the bonded portion. When the pressure is 30 MPa or less, damage to members such as semiconductor elements and semiconductor support members due to pressure is reduced. From this viewpoint, the pressure may be 1 to 30 MPa, 5 to 25 MPa, or 10 to 20 MPa.

[0060] The semiconductor element may be any known semiconductor element, such as a transistor or a diode. Further examples of the semiconductor element include light-emitting elements such as LEDs. The type of light-emitting element is not particularly limited, and examples include light-emitting elements in which a nitride semiconductor such as InN, AlN, GaN, InGaN, AlGaN, or InGaAlN is formed as a light-emitting layer on a substrate by MOCVD (metal organic chemical vapor deposition) or the like. Examples of the semiconductor support member include support members made of copper, copper-plated copper, PPF (pre-plated lead frame), glass epoxy, ceramics, or the like.

[0061] By using the die attach material of this embodiment, semiconductor elements can be bonded to substrates that are not metal-plated. The semiconductor device thus obtained has improved connection reliability against temperature cycles after mounting compared to conventional devices. Furthermore, because the electrical resistance is sufficiently low and changes little over time, there is little decrease in output power over time even when driven for long periods of time, resulting in a long life.

[0062] [Electronic component and manufacturing method thereof] The electronic component of the present disclosure has a joint formed using the paste composition described above. Because the electronic component of the present disclosure has a joint formed using the paste composition described above, it has good heat dissipation properties and connection reliability, and can provide an electronic component for use in an automobile. The electronic component may have an electronic element, a substrate, and a joint that joins the electronic element and the substrate. The joint is formed using the paste composition described above. The manufacturing method of the electronic component of the present disclosure is a manufacturing method of an electronic component that includes a step of forming a joint using the paste composition described above.

[0063] Next, the present disclosure will be described in detail by showing examples, but the present disclosure is not limited to these examples.

[0064] The raw materials used were those shown in Table 1 and below.

[0065] (1) Silver particles

[0066]

[0067] (2) Binder (resin) jER1009 (bisphenol A type solid epoxy resin, manufactured by Mitsubishi Chemical Corporation, molecular weight: 3800, 5% weight loss temperature: 359°C) JP-100 (epoxidized solid epoxy resin, manufactured by Nippon Soda Co., Ltd., molecular weight: 1300, 5% weight loss temperature: 377°C) (3) Solvent TOE-100 (dihydroterpinyloxyethanol, manufactured by Nippon Terpene Chemical Co., Ltd., molecular weight 198.31) (4) Other components Hardener: Percumyl D (dicumyl peroxide, manufactured by NOF Corporation, molecular weight 270.37) Fluxing agent: KE-604 (trade name "Pine Crystal KE-604", hydride of acrylic acid modified rosin, manufactured by Arakawa Chemical Industries, Ltd.)

[0068] [Examples 1 to 7 and Comparative Examples 1 to 10] Each component was mixed according to the formulation shown in Table 2 and kneaded with a roll to obtain a paste composition. The obtained paste composition was evaluated as described below. The results are shown in Table 2.

[0069] [Evaluation] (1) Crystallite diameters S0, S1 and their rate of change {((S1-S0) / S0) × 100} The obtained paste composition was dried at 80 ° C. for 30 minutes to obtain a cake. The obtained cake was applied to a glass plate to a thickness of 200 μm, and an X-ray diffractometer (product name: SmartLab SE, manufactured by Rigaku Corporation) was used. Using a focusing method with CuKα radiation as the radiation source, the crystallite diameter S0 (nm) was calculated from the Miller index (111) plane peak using the Scherrer equation. The fitting function used was a split pseudo-Voigt function, the width was FWHD, and the Scherrer constant was 0.94.

[0070] The cake was heated to 200°C at a heating rate of 60°C / min under a nitrogen atmosphere while applying a pressure of 15 MPa, and then heated and pressurized at 15 MPa and 200°C for 2 minutes, after which the temperature was lowered to room temperature (25°C) at a cooling rate of 110°C / min to obtain a sintered body. The sintered body was pulverized in a mortar to obtain a powder. The powder was applied to a glass plate, and an X-ray diffractometer (product name: SmartLab SE, manufactured by Rigaku Corporation) was used. The crystallite diameter S1 (nm) was calculated using the Miller index (111) plane peak by a focusing method using CuKα radiation as a radiation source, using the Scherrer equation. The fitting function used was a split pseudo-Voigt function, the width was FWHD, and the Scherrer constant was 0.94. Furthermore, the rate of change {((S1-S0) / S0) x 100} (%) was calculated from the above S0 and S1.

[0071] (2) Viscosity The viscosity of the obtained paste composition was measured at a temperature of 25°C and a rotation speed of 2.0 rpm using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., product name: VISCOMETER-TV22, applicable cone-plate type rotor: 3° × R14) (3° cone).

[0072] (3) Thixotropy Index The viscosity (V) of the obtained paste composition was measured at a temperature of 25°C and a rotation speed of 2.0 rpm using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., product name: VISCOMETER-TV22, applied cone-plate rotor: 3° × R14). ２．０ ) and viscosity at 20 rpm (V ２０ ) were measured. ２０ Viscosity V ２．０ Viscosity ratio (V ２．０ / V ２０ ) was used as the thixotropy index.

[0073] (4) Volume Resistivity The obtained paste composition was applied to a glass substrate (thickness 1 mm) by screen printing to a thickness of 30 μm, dried at 120° C. for 10 minutes, heated to 200° C. at a heating rate of 60° C. / min, and cured at 200° C. and 15 MPa for 2 minutes to obtain a wiring. The electrical resistivity of the obtained wiring was measured by a four-terminal method using a resistivity meter (product name "MCP-T600", manufactured by Mitsubishi Chemical Corporation).

[0074] (5) Shear Strength The obtained paste composition was applied by stencil printing to a copper frame and dried at 120°C for 10 minutes. After that, a backside gold chip with a gold vapor deposition layer on a 2 mm x 2 mm bonding surface was mounted on it. The temperature was increased to 200°C at a rate of 60°C / min, and heat-pressure curing was performed at 200°C and 15 MPa for 2 minutes. The hot die shear strength at 260°C was measured using a mount strength measuring device.

[0075] (6) Cooling and Heating Cycle (Production of Bonded Body) The obtained paste composition was applied by stencil printing to a copper frame and dried at 120°C for 10 minutes. After that, a gold-backed silicon chip having a gold vapor-deposited layer on a 5 mm x 5 mm bonding surface was mounted on the frame. The temperature was increased to 200°C at a rate of 60°C / min, and heat-pressure curing was carried out at 200°C and 15 MPa for 2 minutes to obtain a bonded body.

[0076] (Cold-heat cycle treatment) The obtained 10 bonded bodies were subjected to cold-heat cycle treatment. The cold-heat cycle treatment consisted of holding at −55° C. for 30 minutes, then raising the temperature from −55° C. to 150° C. at a temperature increase rate of 30° C. / min, holding at 150° C. for 30 minutes, and then lowering the temperature at a temperature decrease rate of 30° C. / min, with this cycle being performed 2000 times. The bonded bodies that had been subjected to the cold-heat cycle treatment were observed for the presence or absence of peeling of the silicon chip using an ultrasonic microscope (product name "FineSAT II", manufactured by Hitachi Power Solutions Co., Ltd.) and evaluated according to the following criteria.

[0077] OK: 0 out of 10 silicon chips peeled off NG: 1 or more out of 10 silicon chips peeled off

[0078] (7) Particle Size Distribution For each paste composition shown in Table 2, only silver particles were blended among the constituent components of the paste composition in the proportions shown in Table 2 to obtain a measurement sample for the particle size distribution of the silver particles. For example, for the paste composition of Example 2, 90 parts by mass of TC-728 and 10 parts by mass of TC-905 were blended to obtain a measurement sample. The particle size distribution of each measurement sample was measured using a laser diffraction particle size distribution analyzer (product name "SALAD-7500nano", manufactured by Shimadzu Corporation). From the particle size distribution, the average particle diameter (D50) was calculated from the particle size at which the cumulative volume was 50% (50% particle size D50). Furthermore, based on the particle size distribution, the proportions of particles in three regions, 1.0 μm or less, 1.0 to 20 μm, and over 20 μm, were calculated from the frequency of the particle size distribution.

[0079] (8) Specific Surface Area A sample for measuring the specific surface area of ​​silver particles was prepared by the following procedure. That is, for each paste composition shown in Table 2, only the silver particles, among the components of that paste composition, were blended in the ratio shown in Table 2 to obtain a sample for measuring the specific surface area of ​​silver particles. For example, for the paste composition of Example 2, 90 parts by mass of TC-728 and 10 parts by mass of TC-905 were blended to obtain a measurement sample. Each of the obtained measurement samples was degassed at 60°C for 10 minutes, and then the specific surface area was measured by the BET single-point method using nitrogen adsorption using a specific surface area measuring device (Monosorb, manufactured by QuantaChrome).

[0080] (9) 5% Weight Loss Temperature Each resin (jER-1009 and JP-100) was placed in a thermogravimetric and differential thermal analyzer (product name "TG / DTA6200", manufactured by Hitachi High-Tech Science Corporation). The resin was heated from room temperature (25°C) at a heating rate of 10°C / min, and the temperature at which the weight of the resin was reduced by 5% by mass was defined as the 5% weight loss temperature of the resin.

[0081]

[0082] The paste compositions of Examples had a (111) plane crystallite size change rate ({((S1-S0) / S0) × 100} of 250% or more and a content of silver particles having a particle size of more than 20 μm relative to 100% by mass of silver particles of 5% by mass or less, and therefore had good coatability, were capable of pressure bonding at low temperatures, and had high adhesive strength. On the other hand, the paste compositions of Comparative Examples 1 to 3 and 5 to 8 had a rate of change {((S1-S0) / S0) × 100} of less than 250%, and therefore were poor in at least one of the properties of coatability, pressure bonding at low temperatures, and adhesive strength. The paste composition of Comparative Example 4 had a content of silver particles having a particle size of more than 20 μm relative to 100% by mass of silver particles of more than 5% by mass, and therefore were poor in at least one of the properties of coatability, dispersibility, pressure bonding at low temperatures, and adhesive strength. The paste compositions of Comparative Examples 9 and 10 had a content of silver particles (A) of less than 95% by mass relative to 100% by mass of the total amount of silver particles (A) and binder (B), and therefore were poor in at least one of the properties of coatability, dispersibility, pressure-bonding ability at low temperatures, and adhesive strength.

Claims

1. A paste composition comprising silver particles (A) and a binder (B), wherein the content of silver particles (A1) having a particle diameter of more than 20 μm is 5% by mass or less relative to 100% by mass of the silver particles (A), the content of the silver particles (A) is 95% by mass or more relative to 100% by mass of the total amount of the silver particles (A) and the binder (B), and the rate of change expressed by the following formula (1) is 250% or more: Rate of change = (S1 - S0) / S0 × 100 (%) (1) [S0 is the crystallite diameter, in Miller index (111), of the silver particles in a dried product of the paste composition. S1 is the crystallite diameter, in Miller index (111), of the silver particles in a treated product obtained by heating and pressurizing the dried product of the paste composition under a nitrogen atmosphere at 15 MPa and 200°C for 2 minutes.] 2. The paste composition according to claim 1, wherein the content of silver particles (A2) having a particle diameter of 1.0 to 20 μm is 50 mass% or less relative to 100 mass% of the silver particles (A).

3. The paste composition according to claim 1 or 2, wherein the content of silver particles (A3) having a particle diameter of less than 1.0 μm in 100% by mass of the silver particles (A) is 50% by mass or more.

4. The specific surface area of ​​the silver particles (A) is 1.4 m ２ The paste composition according to any one of claims 1 to 3, wherein the solubility is 1 / g or more.

5. The paste composition according to any one of claims 1 to 4, wherein the binder (B) comprises at least one resin selected from the group consisting of thermosetting resins and thermoplastic resins.

6. A paste composition according to any one of claims 1 to 5, wherein the binder (B) has a 5% weight loss temperature of 250°C or higher.

7. The paste composition according to any one of claims 1 to 6, further comprising a solvent (C), wherein the content of the solvent (C) is 10 to 30 mass% relative to 100 mass% in the total amount of the silver particles (A), the binder (B), and the solvent (C).

8. A semiconductor device having a joint formed using the paste composition according to any one of claims 1 to 7.

9. A method for manufacturing a semiconductor device comprising a semiconductor element and a semiconductor support member, comprising the steps of: applying the paste composition according to any one of claims 1 to 7 to the semiconductor support member; mounting the semiconductor element on the paste composition; and bonding the semiconductor element and the semiconductor support member together under heat and pressure, wherein the heat and pressure bonding is performed under conditions of 180 to 300°C, 1 to 30 MPa, and 0.5 to 10 minutes.

10. An electronic component having a joint formed using the paste composition according to any one of claims 1 to 7.

11. A method for producing an electronic component, comprising a step of forming a joint using the paste composition according to any one of claims 1 to 7.

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