WO2018030173A1

WO2018030173A1 - Bonding composition and method for preparing same

Info

Publication number: WO2018030173A1
Application number: PCT/JP2017/027390
Authority: WO
Inventors: 茂樹久保田; 尚耶中島
Original assignee: バンドー化学株式会社
Priority date: 2016-08-10
Filing date: 2017-07-28
Publication date: 2018-02-15
Also published as: TW201805391A; TWI744372B

Abstract

Provided is a bonding composition for obtaining a bonded layer which has a low void rate and a high bonding strength, and excellent heat-resistant reliability, regardless of whether baking is performed in the atmosphere or in an inert atmosphere, and whether plated or unplated substrates are bonded. The bonding composition of the present invention is characterized by including silver nanoparticles, a dispersion medium, and a first carboxylic acid which is attached to at least a portion of the surfaces of the silver nanoparticles and includes an O atom in a carbon chain.

Description

Bonding composition and method for producing the same

The present invention relates to a joining composition used for joining members to be joined such as metal parts and a manufacturing method thereof.

Conventionally, solder, a conductive adhesive, a silver paste, an anisotropic conductive film, or the like is used to mechanically, electrically, or thermally join members to be joined such as metal parts. The members to be joined include not only metal parts but also ceramic parts or resin parts, and different kinds of members to be joined may be joined. For example, there are applications in which light emitting elements such as LEDs are bonded to a substrate, applications in which a semiconductor chip is bonded to a substrate, or applications in which these substrates are further bonded to a heat dissipation member.

Among them, solder containing Pb is also widely used as a bonding material for bonding the members to be bonded. However, in recent years, Pb-free has been demanded from the viewpoint of environmental protection and RoHS regulation, and since solder has a low melting point, it is difficult to apply it to power devices such as silicon carbide and gallium nitride having high operating temperatures. there were.

Therefore, metal paste using metal nanoparticle sintering has attracted attention as a new bonding material with high heat resistance as a bonding material, and a technique for low-temperature sintering using silver nanoparticles as a bonding material is known ( For example, Patent Document 1: Japanese Patent Laid-Open No. 2011-073011, Patent Document 2: Japanese Patent Laid-Open No. 2015-232181, and Patent Document 3: Japanese Patent Laid-Open No. 2011-240406).

More specifically, in Patent Document 1, “providing a bonding technique capable of increasing the bonding strength while leaving the spacer in the bonding layer in the bonding technique using metal nanoparticles” 1, a second member 12, and a bonding layer 13 in which these members 11 and 12 are bonded together while being pressed, and a plastically deformed spacer 14 remains in the bonding layer 13. Has been proposed.

Further, in Patent Document 2, an object is to “provide a bonding metal paste that can secure bonding strength and reduce unevenness in bonding strength even with the simplest possible structure”. Metal submicron particles having a primary particle diameter (D50 diameter) of 0.5 to 3.0 μm, metal nanoparticles having an average primary particle diameter of 1 to 200 nm and coated with a fatty acid having 6 to 8 carbon atoms, and A metal bonding paste (bonding material) composed of a dispersion medium in which is dispersed is proposed.

Further, in Patent Document 3, an object is to “provide a paste containing a flux component capable of forming a metal phase even under an inert atmosphere”, and “average primary particle diameter is 1 to 200 nm, There has been proposed a “joining material composed of silver nanoparticles coated with an organic substance having 8 or less carbon atoms, a flux component having at least two carboxyl groups, and a dispersion medium”.

JP 2011-073011 A Japanese Patent Laying-Open No. 2015-232181 JP 2011-240406 A

However, with the techniques proposed in Patent Document 1 and Patent Document 2, a sufficient bonding state cannot be obtained unless pressure is applied during firing bonding. In the firing under pressure, there are problems such as a decrease in yield due to chip breakage and complication of the production process. In this respect, development of a mounting technique by pressureless bonding is strongly demanded. Moreover, although the technique proposed in the above-mentioned Patent Document 3 can join a small object to be joined having a size of 2 mm × 2 mm, it must be joined under no pressure under nitrogen and has a large size exceeding 5 mm × 5 mm. However, there is still room for improvement from the viewpoint of sufficient bonding strength for bonding of the objects to be bonded and bonding of the objects to be bonded in the air.

Therefore, the present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to perform air firing or inert atmosphere firing, or plating-substrate joining without requiring pressure during firing joining. Alternatively, it is an object of the present invention to provide a bonding composition and a method for producing the same for obtaining a bonding layer having a low void ratio, a high bonding strength, and excellent heat resistance reliability, regardless of substrate bonding without plating.

As a result of earnest research to achieve the above object, the present inventor does not require pressurization during firing bonding, regardless of atmospheric firing or inert atmosphere firing, or plating-bonded substrate bonding or non-plating substrate bonding. In order to obtain a bonding layer having a low void ratio and strong bonding strength and excellent heat resistance reliability, the type of carboxylic acid to be attached to the surface of the silver fine particles is specified, and further, the carboxylic acid contained in the dispersion medium It has been found that specifying the type of is extremely effective in achieving the above object, and the present invention has been achieved.

That is, the present invention
Silver nanoparticles,
A dispersion medium;
A first carboxylic acid containing an O atom in a carbon chain attached to at least a portion of the surface of the silver nanoparticles;
A bonding composition characterized by comprising:

In the bonding composition of the present invention having the above-described configuration, an organic substance adheres to and coats at least a part of the surface of the silver nanoparticles in order to prevent the aggregation by maintaining the dispersion stability of the silver nanoparticles. is doing. If this adhered (coating) organic substance remains during firing, it will need to evaporate or decompose during firing in order to inhibit the fusion of silver nanoparticles. When the evaporation temperature or decomposition temperature is in the vicinity of the firing temperature, the sintering start temperature of the silver nanoparticles and the densification rate of the sintered layer can be increased, and a denser bonding layer can be formed. Therefore, in this invention, carboxylic acid (1st carboxylic acid) with comparatively large adsorption energy with respect to the surface of a silver nanoparticle is used as an organic substance attached to the surface of a silver nanoparticle. This carboxylic acid not only contributes to the stabilization of the silver nanoparticles, but also exhibits an effect as a flux, and thus works advantageously for solid Cu bonding. The present invention includes silver nanoparticles and a first carboxylic acid containing an O atom in a carbon chain attached to at least a part of the surface of the silver nanoparticles. This also relates to silver nanoparticles (coated silver nanoparticles) themselves.

In addition, the first carboxylic acid in the present invention contains an O atom having a high electronegativity in the carbon chain. The O atom of the carbon chain means an O atom other than the O atom contained in the carboxyl group (—COOH). For example, an ether group (—O—), a methoxy group (—OCH 3), an ethoxy group (—OCH 2 CH 3). ), And an O atom contained in an acetyl group (—COCH 3) or the like. When the silver nanoparticles contain O atoms, the wettability with the member to be bonded is increased, and a strong bond with the member to be bonded is formed. Specific examples of the first carboxylic acid include levulinic acid, methoxyacetic acid, ethoxyacetic acid, and 3-ethoxypropionic acid.

In the above bonding composition of the present invention, the carboxylic acid preferably has 5 or less carbon atoms.

When the number of carbons increases, the dispersion stability of the silver nanoparticles improves. However, when the number of carbons increases, the volume of the coating organic matter in the silver nanoparticles increases, which increases the density of the bonding layer formed of the bonding composition. It will be disadvantageous.

In the bonding composition of the present invention, the average primary particle size of the silver nanoparticles is preferably 10 to 100 nm.

The particle size and shape of the silver nanoparticles are not particularly limited as long as the effects of the present invention are not impaired, and various conventionally known silver nanoparticles can be used. Specifically, silver nanoparticles having an average primary particle size of less than 1 μm can be used, and a preferable average particle size is 10 to 100 nm. If the average primary particle diameter of the silver nanoparticles is 10 nm or more, the silver nanoparticles have good low-temperature sinterability, and the production of silver nanoparticles is practical without increasing the cost. Moreover, if it is 100 nm or less, the dispersibility of a silver nanoparticle hardly changes with time, and it is preferable.

In the bonding composition of the present invention, it is preferable that the dispersion medium contains a second carboxylic acid. The second carboxylic acid is preferably a monocarboxylic acid, more preferably ricinoleic acid or oleic acid.

When a carboxylic acid is contained in the dispersion medium, the carboxylic acid acts as a flux, so that it is possible to join a solid Cu joined member. As the number of carboxyl groups increases, the flux effect is higher. However, in the bonding composition of the present invention, a monocarboxylic acid such as ricinoleic acid or oleic acid is sufficiently effective, and a solid Cu bonded member can be bonded well. it can.

The bonding composition of the present invention may include silver microparticles having an average particle diameter of 1 to 15 μm.

Here, the particle size of the silver nanoparticles may not be constant. As described above, the average primary particle diameter of the silver nanoparticles is preferably 100 nm or less, but the bonding composition does not cause aggregation and the effect of the present invention is not significantly impaired. Silver nanoparticles having an average average primary particle size may be included. In addition, if necessary, silver microparticles having an average particle diameter of 1 to 15 μm may be added.

The present invention also relates to a method for producing the above-described bonding composition of the present invention,
A first step of producing silver nanoparticles by a silver oxalate complex decomposition method,
The carboxylic acid is added to at least a part of the surface of the silver nanoparticle by heating the silver nanoparticle obtained in the first step by adding a first carboxylic acid containing an O atom to a portion other than the carboxyl group. A second step of attaching
It is characterized by including.

According to the method for producing a bonding composition of the present invention having such a configuration, the above-described bonding composition of the present invention can be suitably produced.

According to the present invention, there is no need for pressure at the time of firing joining, regardless of air firing or inert atmosphere firing, or plating-bonded substrate bonding or non-plating substrate bonding. A bonding composition that realizes a bonding layer having heat resistance reliability and a method for manufacturing the same can be provided.

Hereinafter, (1) one preferred embodiment of the bonding composition of the present invention, (2) one preferred embodiment of the method for producing the bonding composition of the present invention, and (3) the bonding composition of the present invention. A preferred embodiment of a method for joining the members to be joined (a method for producing a joined body) will be described in detail. In the following description, overlapping description may be omitted.

(1) Bonding composition The bonding composition of the present embodiment includes silver nanoparticles, a dispersion medium, and carbon atoms that are attached to at least a part of the surface of the silver nanoparticles and contain O atoms. It is the composition for joining characterized by including one carboxylic acid. Hereinafter, each of these components will be described.

(1-1) Silver Nanoparticles The particle size and shape of the silver nanoparticles are not particularly limited as long as the effects of the present invention are not impaired, and various conventionally known silver nanoparticles can be used. Specifically, silver nanoparticles having an average primary particle size of less than 1 μm can be used, and a preferable average particle size is 10 to 100 nm. If the average primary particle diameter of the silver nanoparticles is 10 nm or more, the silver nanoparticles have good low-temperature sinterability, and the production of silver nanoparticles is practical without increasing the cost. Moreover, if it is 100 nm or less, the dispersibility of a silver nanoparticle hardly changes with time, and it is preferable.

If the average primary particle size of the silver nanoparticles is too small, the effect of the increase in volume occupied by the coating organic matter becomes large, and if the average primary particle size of the silver nanoparticles is too large, the fusion temperature is increased and the sintered layer is increased. This is because the densification rate of the film is reduced.

In consideration of the problem of migration of the bonding layer formed using the bonding composition of the present invention, particles such as gold, copper, platinum, palladium, etc., in which the ionization column is more noble than hydrogen, You may add in the range which does not impair the effect of invention.

Moreover, the particle size of the silver nanoparticles in the bonding composition of the present embodiment may not be constant. As described above, the average primary particle diameter of the silver nanoparticles is preferably 100 nm or less, but the bonding composition does not cause aggregation and the effect of the present invention is not significantly impaired. Silver nanoparticles having an average average primary particle size may be included.

In addition, if necessary, inorganic microparticles (inorganic coarse particles) such as silver microparticles having an average particle diameter of 1 to 15 μm may be added. In such a case, a favorable conductive path can be obtained by causing the nanometer-sized silver nanoparticles to drop in melting point around the micron-sized inorganic microparticles.

Here, the particle diameters of the silver nanoparticles and the inorganic microparticles in the bonding composition of the present embodiment can be measured by a dynamic light scattering method, a small-angle X-ray scattering method, and a wide-angle X-ray diffraction method. In order to show the melting point drop of nano-sized silver fine particles, the crystallite diameter determined by the wide-angle X-ray diffraction method is appropriate. For example, in the wide-angle X-ray diffraction method, more specifically, RINT-UltimaIII manufactured by Rigaku Corporation can be used to measure 2θ in the range of 30 to 80 ° by the diffraction method. In this case, the sample may be measured by extending it thinly so that the surface becomes flat on a glass plate having a recess of about 0.1 to 1 mm in depth at the center. The crystallite diameter (D) calculated by substituting the half width of the obtained diffraction spectrum into the following Scherrer equation using JADE manufactured by Rigaku Corporation may be used as the particle diameter.
D = Kλ / Bcos θ
Here, K: Scherrer constant (0.9), λ: wavelength of X-ray, B: half width of diffraction line, θ: Bragg angle.

The particle size of the inorganic microparticle is not particularly limited as long as it is larger than the particle size of the silver nanoparticle, but the average particle size is preferably 1 to 50 μm. By setting the average particle size of the inorganic microparticles to 1 μm or more, it is possible to ensure good dispersibility of the inorganic microparticles and to sufficiently increase the average particle size difference from the silver nanoparticles. Densification by mixing can be achieved. Moreover, it can prevent that a joining layer becomes too thick because the average particle diameter of an inorganic microparticle shall be 50 micrometers or less.

Examples of constituent elements of the inorganic microparticles in the bonding composition of the present embodiment include gold, silver, copper, nickel, bismuth, tin, iron, and platinum group elements (ruthenium, rhodium, palladium, osmium, iridium, and platinum). At least one of them can be mentioned. The constituent element is preferably at least one selected from the group consisting of gold, silver, copper, nickel, bismuth, tin, or a platinum group element, and further has a smaller ionization tendency than copper or copper ( It is preferably a noble metal, ie, at least one of gold, platinum, silver and copper, and most preferably silver. These elements may be used singly or in combination of two or more. The methods of using these elements in combination include the case of using alloy particles containing a plurality of metals, the metal having a core-shell structure or a multilayer structure. Particles may be used.

For example, when silver microparticles are used as the inorganic microparticles, the conductivity of the adhesive layer formed using the bonding composition of this embodiment is good, but silver and other metals are considered in consideration of migration problems. By using the bonding composition comprising: migration can be made difficult to occur. The “other metal” is preferably a metal in which the ionization column is more noble than hydrogen, that is, gold, copper, platinum, or palladium.

The combination of the inorganic microparticles and the silver nanoparticles in the bonding composition of the present embodiment is not particularly limited as long as the effects of the present invention are not impaired, and the silver nanoparticles and the inorganic microparticles having a low temperature sintering property Can be combined. Two or more kinds of silver nanoparticles and inorganic microparticles may be combined.

(1-2) First carboxylic acid (organic substance)
In the bonding composition of the present embodiment, an organic substance “first carboxylic acid containing an O atom in a carbon chain” is attached to at least a part of the surface of the silver nanoparticles, and the first carboxylic acid The acid partially or totally covers the surface of the silver nanoparticles. The first carboxylic acid substantially constitutes colloidal silver particles together with the silver nanoparticles as a so-called dispersant in the bonding composition of the present embodiment. The carboxyl group in one molecule of the first carboxylic acid has a relatively high polarity and tends to cause an interaction due to a hydrogen bond, but a portion other than these functional groups has a relatively low polarity. Furthermore, the carboxyl group tends to exhibit acidic properties.

In addition to the first carboxylic acid, the compound adhering to the surface of the silver nanoparticles is a trace amount of organic matter contained as impurities from the beginning of the silver nanoparticles, adhering to the silver nanoparticles by mixing in the manufacturing process described later. It is a concept that does not include trace organic substances, organic substances adhered to silver nanoparticles, such as residual reducing agents and residual dispersants that could not be removed in the cleaning process. The “trace amount” is specifically intended to be less than 1% by mass in the silver colloid particles.

The first carboxylic acid is an organic substance capable of covering silver nanoparticles to prevent aggregation of the silver nanoparticles and forming silver colloidal particles, and the form of the coating is not particularly defined. In the embodiment, from the viewpoint of dispersibility, conductivity, and the like, a coating organic substance (for example, an amine) other than the first carboxylic acid may be included within a range not impairing the effects of the present invention. In addition, when these organic substances are chemically or physically bonded to the silver nanoparticles, it is considered that the organic substances are changed to anions and cations. In this embodiment, ions derived from these coated organic substances are used. And the like are also included in the above-mentioned coated organic matter.

Such an amine may be linear or branched, and may have a side chain. For example, N- (3-methoxypropyl) propane-1,3-diamine, 1,2-ethanediamine, 2-methoxyethylamine, 3-methoxypropylamine, 3-ethoxypropylamine, 1,4-butanediamine, , Diamines such as 5-pentanediamine, pentanolamine, aminoisobutanol, alkoxyamines, aminoalcohols, as well as alkylamines such as propylamine, butylamine, pentylamine, hexylamine (linear alkylamines, with side chains) ), Cycloalkylamines such as cyclopentylamine and cyclohexylamine, primary amines such as aniline and allylamine, secondary amines such as dipropylamine, dibutylamine, piperidine and hexamethyleneimine, and tripropylamine , Dimethyl group Bread diamine, cyclohexyldimethylamine, pyridine, tertiary amines such as quinoline.

The amine may be a compound containing a functional group other than an amine such as a hydroxyl group, a carboxyl group, an alkoxy group, a carbonyl group, an ester group, or a mercapto group. Moreover, the said amine may be used independently, respectively and may use 2 or more types together. In addition, the boiling point at normal pressure is preferably 300 ° C. or lower, more preferably 250 ° C. or lower.

Here, the 1st carboxylic acid contains O atom with high electronegativity in a carbon chain. This O atom means an O atom other than the O atom contained in the carboxyl group (—COOH). For example, an ether group (—O—), a methoxy group (—OCH ₃ ), an ethoxy group (—OCH ₂ CH _3). ), And an O atom contained in an acetyl group (—COCH ₃ ) and the like. When the silver nanoparticles contain O atoms, the wettability with the member to be bonded is increased, and a strong bond with the member to be bonded is formed.

Furthermore, in the bonding composition of the present embodiment, it is preferable that the carboxylic acid has 5 or less carbon atoms. When the number of carbons increases, the dispersion stability of the silver nanoparticles improves. However, when the number of carbons increases, the volume of the coating organic matter in the silver nanoparticles increases, which increases the density of the bonding layer formed of the bonding composition. It will be disadvantageous.

Specific examples of the first carboxylic acid include monomethyl malonate, levulinic acid, methoxyacetic acid, ethoxyacetic acid, and 3-ethoxypropionic acid. Of these, levulinic acid, methoxyacetic acid, ethoxyacetic acid or 3-ethoxypropionic acid is preferable.

The content of the coating organic substance (first carboxylic acid) in the silver colloid in the bonding composition of the present embodiment is preferably 0.1 to 50% by mass. If the organic matter content is 0.1% by mass or more, the storage stability of the resulting bonding composition tends to be improved, and if it is 50% by mass or less, the conductivity of the bonding composition tends to be good. is there. A more preferable content of the organic substance is 0.3 to 30% by mass, and a more preferable content is 0.5 to 15% by mass.

(1-3) Dispersion medium The bonding composition of the present embodiment may contain various dispersion media as long as the effects of the present invention are not impaired, but preferably contains a second carboxylic acid in the dispersion medium. . When the second carboxylic acid is contained in the dispersion medium, the second carboxylic acid works as a flux, and therefore, it is more suitable for bonding of a pure Cu bonded member. The more the carboxyl groups, the higher the flux effect, but the bonding composition of the present embodiment is sufficiently effective even with monocarboxylic acids such as ricinoleic acid or oleic acid, and bonds solid Cu-bonded members well. Can do.

The second carboxylic acid may be a monocarboxylic acid different from the first carboxylic acid as long as it does not adhere to the surface of the silver nanoparticles and satisfies the condition that the boiling point is 200 ° C. or higher. Furthermore, it is preferable that the second carboxylic acid is ricinoleic acid or oleic acid.

As the dispersion medium, for example, hydrocarbons, alcohols, ethers and esters can be used. Examples of the hydrocarbon include aliphatic hydrocarbons, cyclic hydrocarbons and alicyclic hydrocarbons, and each may be used alone or in combination of two or more.

Examples of the hydrocarbon include aliphatic hydrocarbons, cyclic hydrocarbons, alicyclic hydrocarbons and unsaturated hydrocarbons, and each may be used alone or in combination of two or more.
Examples of the aliphatic hydrocarbon include saturated or unsaturated aliphatic hydrocarbons such as tetradecane, octadecane, heptamethylnonane, tetramethylpentadecane, hexane, heptane, octane, nonane, decane, tridecane, methylpentane, normal paraffin, and isoparaffin. Is mentioned.
Examples of the cyclic hydrocarbon include toluene and xylene.
Alicyclic hydrocarbons include, for example, limonene, dipentene, terpinene, nesol, sinene, orange flavor, terpinolene, ferrandlene, mentadiene, teleben, cymen, dihydrocymene, moslen, kautssin, cajeptene, pinene, turpentine, menthane, pinan. Terpene, cyclohexane and the like.

Examples of the unsaturated hydrocarbon include ethylene, acetylene, benzene, 1-hexene, 1-octene, 4-vinylcyclohexene, terpene alcohol, allyl alcohol, oleyl alcohol, 2-palmitoleic acid, petrothelic acid, oleic acid, and elaidin. Examples include acid, thianic acid, ricinoleic acid, linoleic acid, linoleic acid, linolenic acid, arachidonic acid, acrylic acid, methacrylic acid, gallic acid, and salicylic acid.

Of these, unsaturated hydrocarbons having a hydroxyl group are preferred. The hydroxyl group is easily coordinated to the surface of the silver nanoparticle, and aggregation of the silver nanoparticle can be suppressed. Examples of the unsaturated hydrocarbon having a hydroxyl group include terpene alcohol, allyl alcohol, oleyl alcohol, thianic acid, ricinoleic acid, gallic acid, and salicylic acid. Preferably, it is an unsaturated fatty acid having a hydroxyl group, and examples thereof include thianic acid, ricinoleic acid, gallic acid and salicylic acid.

The unsaturated hydrocarbon is preferably ricinoleic acid. Ricinoleic acid has a carboxyl group and a hydroxyl group and is adsorbed on the surface of the inorganic particles to uniformly disperse the inorganic particles and promote fusion of the inorganic particles.

Alcohol is a compound containing one or more OH groups in the molecular structure, and examples thereof include aliphatic alcohols, cyclic alcohols and alicyclic alcohols, and each may be used alone or in combination of two or more. Also good. Moreover, a part of OH group may be induced | guided | derived to the acetoxy group etc. in the range which does not impair the effect of this invention.

Examples of the aliphatic alcohol include heptanol, octanol (1-octanol, 2-octanol, 3-octanol, etc.), nonanol, decanol (1-decanol, etc.), lauryl alcohol, tetradecyl alcohol, cetyl alcohol, isotridecanol. And saturated or unsaturated C6-30 aliphatic alcohols such as 2-ethyl-1-hexanol, octadecyl alcohol, hexadecenol and oleyl alcohol.
Examples of the cyclic alcohol include cresol and eugenol.

Further, as the alicyclic alcohol, for example, cycloalkanol such as cyclohexanol, terpineol (including α, β, γ isomers, or any mixture thereof), terpene alcohol such as dihydroterpineol (monoterpene alcohol etc. ), Dihydroterpineol, myrtenol, sobrerol, menthol, carveol, perillyl alcohol, pinocarveol, berbenol, tersolve (MTPH) and the like.

The content when the dispersion medium is contained in the bonding composition of the present embodiment may be adjusted according to desired properties such as viscosity, and the content of the dispersion medium in the bonding composition is 1 to 30 masses. % Is preferred. When the content of the dispersion medium is 1 to 30% by mass, the effect of adjusting the viscosity can be obtained within a range that is easy to use as a bonding composition. A more preferable content of the dispersion medium is 1 to 20% by mass, and a more preferable content is 1 to 15% by mass. In addition, when there is too much content of a dispersion medium, there exists a possibility that many voids resulting from volatilization of a dispersion medium may generate | occur | produce in a joining layer.

(1-4) Other components In addition to the above components, the bonding composition of the present embodiment has an appropriate viscosity, adhesiveness, and drying property in accordance with the intended use within a range not impairing the effects of the present invention. Alternatively, in order to impart functions such as printability, a polymer dispersant, for example, an oligomer component that serves as a binder, a resin component, an organic solvent (a part of the solid content may be dissolved or dispersed), an interface. You may add arbitrary components, such as an activator, a thickener, or a surface tension modifier. Such optional components are not particularly limited.

As the polymer dispersant, a commercially available polymer dispersant can be used. Examples of the commercially available polymer dispersant include, for example, Solsperse 11200, Solsperse 13940, Solsperse 16000, Solsperse 17000, Solsperse 18000, Solsperse 20000, Solsperse 24000, Solsperse 26000, Solsperse 27000, Solsperse. 28000 (manufactured by Nippon Lubrizol Corporation); DISPERBYK-102, 110, 111, 170, 190.194N, 2015, 2090, 2096 (manufactured by Big Chemie Japan Co., Ltd.); EFKA-46, EFKA-47, EFKA- 48, EFKA-49 (manufactured by EFKA Chemical); polymer 100, polymer 120, polymer 150, polymer 400, polymer 401, polymer 02, polymer 403, polymer 450, polymer 451, polymer 452, polymer 453 (manufactured by EFKA Chemical); Ajisper PB711, Azisper PA111, Azisper PB811, Azisper PW911 (manufactured by Ajinomoto Co.); Examples include Floren DOPA-17, Floren TG-730W, Floren G-700, Floren TG-720W (manufactured by Kyoeisha Chemical Industry Co., Ltd.), Big Chemie's DISPERBYK series, and 610, 610S, and 630 , 651, 655, 750 W, 755 W, etc., and the Disparon series of Enomoto Kasei includes DA-375, DA-1200, etc. From the viewpoint of stability, DISPERBYK-102, Solsperse 11200, Solsperse 13940, Solsperse 16000, Solsperse 17000, Solsperse 18000, it is preferable to use Solsperse 28000.

The content of the polymer dispersant is preferably 0.1 to 15% by mass. When the content of the polymer dispersant is 0.1% or more, the dispersion stability of the resulting bonding composition is improved. However, when the content is too large, the dispersion stability is lowered. From such a viewpoint, the more preferable content of the polymer dispersant is 0.03 to 3% by mass, and still more preferable content is 0.05 to 2% by mass.

Examples of the resin component include polyester resins, polyurethane resins such as blocked isocyanate, polyacrylate resins, polyacrylamide resins, polyether resins, melamine resins, and terpene resins. May be used alone or in combination of two or more.

Here, when the member to be joined is, for example, polyethylene terephthalate (PET), as the resin component, polyvinyl alcohol, polyvinyl pyrrolidone, vinyl chloride-vinyl acetate copolymer having good adhesion to the PET itself. , Polyvinyl acetoacetal, and polyvinyl butyral may be used. Examples of such ketone-formaldehyde condensates and hydrogenated products thereof include Evonik Degussa Japan Co., Ltd. TEGO (registered trademark) VariPlus series (SK, AP, etc.), and vinyl chloride-vinyl acetate copolymers include Nisshin Chemical. Solvain (registered trademark) series (Solvine AL, etc.) manufactured by Kogo Oil Co., Ltd. is used as polyvinyl acetoacetal and polyvinyl butyral. Etc.). Among them, polyvinylpyrrolidone is preferably used because it has high solubility in highly polar polyhydric alcohols (particularly diol solvents) and can be dissolved well in solvents such as esters and ketones.

Examples of the thickener include clay minerals such as clay, bentonite or hectorite, for example, polyester emulsion resin, acrylic emulsion resin, polyurethane emulsion resin or emulsion such as blocked isocyanate, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose. , Cellulose derivatives such as hydroxypropylcellulose and hydroxypropylmethylcellulose, polysaccharides such as xanthan gum and guar gum, and the like. These may be used alone or in combination of two or more.

A surfactant different from the above organic substance may be added. In a multi-component solvent-based inorganic colloidal dispersion, the coating surface becomes rough and the solid content tends to be uneven due to the difference in volatilization rate during drying. By adding a surfactant to the bonding composition of the present embodiment, these disadvantages can be suppressed, and a bonding composition that can form a uniform conductive film is obtained. The surfactant that can be used in the present embodiment is not particularly limited, and any of an anionic surfactant, a cationic surfactant, and a nonionic surfactant can be used, for example, an alkylbenzene sulfonate. A quaternary ammonium salt etc. are mentioned. Since the effect can be obtained with a small addition amount, a fluorosurfactant is preferable.

Here, the bonding composition of the present embodiment includes silver colloid particles in which silver nanoparticles are colloided as a main component. Regarding the form of the silver colloid particles, for example, the surface of the silver nanoparticles is used. Silver colloidal particles composed of a part of the first carboxylic acid attached, silver colloidal particles composed of the above-mentioned silver nanoparticles as a core and the surface of which is coated with the first carboxylic acid, Examples thereof include silver colloidal particles that are mixed, but are not particularly limited. Of these, silver colloidal particles having silver nanoparticles as a core and the surface thereof being coated with a first carboxylic acid are preferred. A person skilled in the art can appropriately prepare silver colloid particles having the above-described form using a well-known technique in the art.

As described above, the bonding composition of the present embodiment is composed of the silver nanoparticles, the first carboxylic acid, and the dispersion medium. However, the silver nanoparticles, the first carboxylic acid, and the dispersion medium (and other optional components) are used. In addition to (component), an organic component that does not constitute silver colloidal particles, a residual reducing agent, and the like may be included.

The viscosity of the bonding composition of the present embodiment may be adjusted as appropriate within the range where the solid content does not impair the effects of the present invention. For example, the viscosity may be in the range of 0.01 to 5000 Pa · S, and may be 0. A viscosity range of 1 to 1000 Pa · S is more preferable, and a viscosity range of 1 to 100 Pa · S is particularly preferable. By setting it as the said viscosity range, a wide method is applicable as a method of apply | coating the composition for joining on a base material.

Examples of the method for applying the bonding composition on the substrate include dipping, screen printing, spray method, bar coating method, spin coating method, ink jet method, dispenser method, pin transfer method, application method by brush, casting Method, flexo method, gravure method, offset method, transfer method, hydrophilic / hydrophobic pattern method, syringe method and the like can be appropriately selected and employed. From the viewpoint of viscosity, a dispenser method, a pin transfer method, screen printing, or the like is particularly preferable.

Viscosity is adjusted by adjusting the particle size of silver nanoparticles, adjusting the content of organic matter, adjusting the amount of dispersion medium and other components added, adjusting the blending ratio of each component, and adding a thickener. Can do. The viscosity of the bonding composition can be measured, for example, with a cone plate viscometer (for example, a rheometer MCR301 manufactured by Anton Paar).

(2) Production of Bonding Composition Next, in order to produce the bonding composition of the present embodiment, silver nanoparticles (silver colloid particles) coated with the first carboxylic acid as the main component are used. Prepare.

The first carboxylic acid, the dispersion medium, other components, and the weight reduction rate are not particularly limited, but it is easy to adjust by heating. Moreover, you may carry out by adjusting the quantity of the 1st carboxylic acid etc. which are added when producing a silver nanoparticle, and you may change the washing conditions and frequency | counts after silver nanoparticle preparation.

Heating can be performed with an oven or an evaporator. The heating temperature may be in the range of about 50 to 300 ° C., and the heating time may be several minutes to several hours. Heating may be performed under reduced pressure. By heating under reduced pressure, the amount of the first carboxylic acid can be adjusted at a lower temperature. When performed under normal pressure, it can be performed in air or in an inert atmosphere. Further, the first carboxylic acid, amine or the like can be added later for fine adjustment of the organic matter amount.

The method for preparing silver nanoparticles coated with the first carboxylic acid of the present embodiment is not particularly limited. For example, a dispersion containing silver nanoparticles is prepared, and then the dispersion is washed. Methods and the like. As a step of preparing a dispersion containing silver nanoparticles, for example, a metal salt (or metal ion) dissolved in a solvent may be reduced as described below. As a reduction procedure, a chemical reduction method is used. A procedure based on this may be adopted.

That is, the silver nanoparticles coated with the first carboxylic acid as described above include a silver salt constituting the silver nanoparticles, a first carboxylic acid as a dispersant, a dispersion medium (basically toluene or the like). And may contain water)), and may be prepared by reducing a raw material liquid (some of the components may be dispersed without being dissolved). By this reduction, silver colloidal particles in which the first carboxylic acid as a dispersant is attached to at least a part of the surface of the silver nanoparticles are obtained. The bonding composition of the present invention can be obtained by adding the silver colloidal particles to the dispersion medium in the step described later.

As a starting material for obtaining silver nanoparticles coated with the first carboxylic acid, various known metal salts or hydrates thereof can be used, for example, silver nitrate, silver sulfate, silver chloride, silver oxide. Silver salts such as silver acetate, silver oxalate, silver formate, silver nitrite, silver chlorate and silver sulfide; for example, gold salts such as chloroauric acid, potassium gold chloride and sodium gold chloride; Platinum salts such as platinum, platinum oxide, potassium chloroplatinate; for example, palladium salts such as palladium nitrate, palladium acetate, palladium chloride, palladium oxide, palladium sulfate, etc. can be dissolved in a suitable dispersion medium, And if it is reducible, it will not specifically limit. These may be used alone or in combination.

In addition, the method for reducing these metal salts in the raw material liquid is not particularly limited, and examples thereof include a method using a reducing agent, a method of irradiating light such as ultraviolet rays, electron beams, ultrasonic waves, or thermal energy. Among these, a method using a reducing agent is preferable from the viewpoint of easy operation.

Examples of the reducing agent include amine compounds such as dimethylaminoethanol, methyldiethanolamine, triethanolamine, phenidone, and hydrazine; for example, hydrogen compounds such as sodium borohydride, hydrogen iodide, and hydrogen gas; for example, carbon monoxide. Oxides such as sulfurous acid; for example, ferrous sulfate, iron oxide, iron fumarate, iron lactate, iron oxalate, iron sulfide, tin acetate, tin chloride, tin diphosphate, tin oxalate, tin oxide, sulfuric acid Low valent metal salts such as tin; for example, sugars such as ethylene glycol, glycerin, formaldehyde, hydroquinone, pyrogallol, tannin, tannic acid, salicylic acid, D-glucose, etc. There is no particular limitation as long as it can be reduced. When the reducing agent is used, light and / or heat may be added to promote the reduction reaction.

As a specific method for preparing silver nanoparticles coated with the first carboxylic acid using the above metal salt, organic component, solvent and reducing agent, for example, the above metal salt is used as an organic solvent (for example, toluene). There is a method in which a metal salt solution is prepared by dissolving in, and an organic substance as a dispersant is added to the metal salt solution, and then a solution in which the reducing agent is dissolved is gradually added dropwise.

In the dispersion containing silver nanoparticles coated with the first carboxylic acid as the dispersant obtained as described above, in addition to the silver nanoparticles, the metal salt counterion, the reducing agent residue, There is a dispersant, and the electrolyte concentration in the whole liquid tends to be high. Since the liquid in such a state has high electrical conductivity, the silver nanoparticles are likely to coagulate and precipitate easily. Alternatively, even if precipitation does not occur, the conductivity of the metal salt may deteriorate if the counter ion of the metal salt, the residue of the reducing agent, or an excessive amount of dispersant remaining in the amount necessary for dispersion remains. Therefore, by washing the solution containing silver nanoparticles to remove excess residues, silver nanoparticles coated with the first carboxylic acid can be reliably obtained.

As the washing method, for example, a dispersion containing silver nanoparticles coated with the first carboxylic acid is allowed to stand for a certain period of time, and the resulting supernatant is removed, and then alcohol (methanol or the like) is added and again. Desalting by a method of repeating the process of removing the supernatant liquid generated by stirring the mixture and allowing to stand for a certain period of time, a method of centrifuging instead of the above-mentioned standing, an ultrafiltration device, an ion exchange device, etc. Methods and the like. By removing the organic solvent by such washing, the silver nanoparticles coated with the first carboxylic acid of this embodiment can be obtained.

The bonding composition of the present embodiment can be obtained by mixing the silver nanoparticles coated with the first carboxylic acid obtained above and the dispersion medium described in the present embodiment. The method for mixing the silver nanoparticles coated with the first carboxylic acid and the dispersion medium is not particularly limited, and can be performed by a conventionally known method using a stirrer or a stirrer. An ultrasonic homogenizer with an appropriate output may be applied by stirring with a spatula or the like.

When obtaining a metal colloid dispersion liquid containing a plurality of metals, the production method is not particularly limited. For example, when producing a metal colloid dispersion liquid composed of silver and other metals, the above first carboxylic acid dispersion liquid is used. In the preparation of acid-coated silver nanoparticles, a dispersion containing silver nanoparticles and a dispersion containing other metal nanoparticles may be produced separately and then mixed, and a silver ion solution and other The metal ion solution may be mixed and then reduced.

(3) Joining method If the composition for joining of this embodiment is used, high joining strength can be obtained in joining of the members accompanied by heating. That is, a bonding composition application step of applying the bonding composition between the first bonded member and the second bonded member, and the first bonded member and the second bonded member The first member to be joined and the second member to be joined can be joined by a joining step of firing and joining the joining composition applied between them at a desired temperature (for example, 300 ° C. or lower). it can. At this time, it is possible to apply pressure, but it is also one of the advantages of the present invention that sufficient bonding strength can be obtained without particularly applying pressure. In addition, when firing, the temperature can be raised or lowered stepwise. It is also possible to apply a surfactant or a surface activator to the surface of the member to be joined in advance.

As a result of intensive studies, the inventor uses the above-described bonding composition of the present embodiment as the bonding composition in the bonding composition application step. It was found that the member to be joined can be more reliably joined with high joining strength (a joined body is obtained).

Here, “application” of the bonding composition of the present embodiment is a concept including both the case where the bonding composition is applied in a planar shape and the case where the bonding composition is applied (drawn) in a linear shape. The shape of the coating film made of the bonding composition in a state before being applied and fired by heating can be changed to a desired shape. Therefore, in the joined body of this embodiment after firing by heating, the joining composition is a concept that includes both a planar joining layer and a linear joining layer. The bonding layer may be continuous or discontinuous, and may include a continuous portion and a discontinuous portion.

The first member to be bonded and the second member to be bonded that can be used in the present embodiment are not particularly limited as long as they can be bonded by applying a bonding composition and baking by heating. However, it is preferable that the member has a heat resistance that is not damaged by the temperature at the time of joining.

Examples of the material constituting such a member to be joined include polyamide (PA), polyimide (PI), polyamideimide (PAI), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN). Examples thereof include polyester, polycarbonate (PC), polyethersulfone (PES), vinyl resin, fluororesin, liquid crystal polymer, ceramics, glass, metal and the like, and among them, a metal joined member is preferable. The metal member to be joined is preferable because it is excellent in heat resistance and in affinity with the joining composition of the present invention in which the silver nanoparticles are metal.

The member to be joined may have various shapes such as a plate shape or a strip shape, and may be rigid or flexible. The thickness of the substrate can also be selected as appropriate. In order to improve adhesion or adhesion, or for other purposes, a member on which a surface layer is formed or a member subjected to a surface treatment such as a hydrophilic treatment may be used.

In the step of applying the bonding composition to the members to be bonded, various methods can be used. As described above, for example, dipping, screen printing, spraying, bar coating, spin coating, and inkjet It can be used by appropriately selecting from a formula, a dispenser type, a pin transfer method, a brush application method, a casting method, a flexo method, a gravure method, a syringe method, and the like.

The coated film after coating as described above is baked by heating to a temperature of 300 ° C. or less, for example, within a range that does not damage the member to be bonded, and the bonded body of this embodiment can be obtained. In the present embodiment, as described above, since the bonding composition of the present embodiment is used, a bonding layer having excellent adhesion to a member to be bonded is obtained, and a strong bonding strength is more reliably ensured. can get.

In the present embodiment, when the bonding composition includes a binder component, the binder component is also sintered from the viewpoint of improving the strength of the bonding layer and the bonding strength between the bonded members. The main purpose of the binder component is to adjust the viscosity of the bonding composition for application to various printing methods, and the binder condition may be controlled to remove all the binder component.

The method for performing the firing is not particularly limited. For example, the temperature of the bonding composition applied or drawn on a member to be bonded using a conventionally known oven or the like is, for example, 300 ° C. or lower. It can join by baking. The lower limit of the firing temperature is not necessarily limited, and is preferably a temperature at which the members to be joined can be joined and does not impair the effects of the present invention. Here, in the bonding composition after firing, in order to obtain as high a bonding strength as possible, the remaining amount of the organic matter is preferably small, but a part of the organic matter remains within the range not impairing the effect of the present invention. It does not matter.

In addition, although the 1st carboxylic acid which is organic substance is contained in the joining composition of this invention, unlike what used the thermosetting of the conventional epoxy resin etc., for example, after baking by the effect | action of organic substance The bonding strength is not obtained, and sufficient bonding strength can be obtained by fusing the silver nanoparticles fused as described above. For this reason, even after bonding, even if the remaining organic matter is deteriorated or decomposed / dissipated in a use environment higher than the bonding temperature, there is no risk of the bonding strength being lowered, and therefore the heat resistance is excellent. Yes.

According to the bonding composition of the present embodiment, since it is possible to realize a bonding having a bonding layer that exhibits high conductivity even by baking at a low temperature of about 300 ° C., the members to be bonded are relatively heat-sensitive. Can be joined. Further, the firing time is not particularly limited, and may be any firing time that can be bonded according to the firing temperature.

In this embodiment, in order to further improve the adhesion between the member to be bonded and the bonding layer, the surface of the member to be bonded may be subjected to a surface treatment. Examples of the surface treatment method include a method of performing dry treatment such as corona treatment, plasma treatment, UV treatment, and electron beam treatment, and a method of previously providing a primer layer and a conductive paste receiving layer on a substrate.

As mentioned above, although typical embodiment of this invention was described, this invention is not limited only to these. In the following, the bonding composition of the present invention will be further described in Examples, but the present invention is not limited to these Examples.

Example 1
A total of 50 mmoles of 40 mmol of 3-ethoxypropylamine and 10 mmol of dodecylamine were mixed and sufficiently stirred with a magnetic stirrer. While stirring, 10 mmol of silver oxalate prepared separately was added to increase the viscosity. The resulting viscous material was placed in a 120 ° C. constant temperature bath and reacted for about 15 minutes to obtain a reaction product. Thereafter, 100 mmol of methoxyacetic acid was added to the reaction product, which was again placed in a constant temperature bath at 100 ° C. and stirred for 15 minutes. After stirring by adding 10 ml of methanol, metallic silver nanoparticles were precipitated and separated by centrifugation, and the supernatant was discarded. This operation was repeated once more to obtain metallic silver nanoparticles.
The average primary particle size was calculated using a particle image photographed by SEM (S-4800, manufactured by Hitachi, Ltd.). When the primary particle size was measured using image processing software (MITANI CORPORATION, Win ROOF) for a total of 200 or more particles from 5 or more SEM images at different shooting points, the average primary particle size was calculated by arithmetic average. It was 40 nm.
In addition, 2 g of the obtained metal silver nanoparticles were added to 1 g of micron silver particles (D50 = 2.5 μm, manufactured by Fukuda Metal Foil Powder Co., Ltd.), 0.3 g of isotridecanol as a dispersion medium, and 0.002 g of ricinoleic acid. A predetermined amount was added and mixed by stirring to obtain a bonding composition. And the following evaluation tests were done and the results are shown in Table 1.

[Evaluation Test 1] Measurement of Bonding Strength The bonding composition was applied to a silver-plated layer (20 mm square, 1 mm thick) using a metal mask to a 1 mm square, and a gold-plated Si chip ( 1 mm square) was laminated. The obtained laminate was placed in a reflow furnace (manufactured by Shin Apex Co., Ltd.), and calcination was performed at a maximum temperature of 280 ° C. for 60 minutes in total from the temperature rise to the removal in the air atmosphere. During the firing treatment, no pressure was applied and no pressure was applied. After taking out the laminate, a bonding strength (shear strength) test was performed using a bond tester (manufactured by Reska Co., Ltd.) at room temperature.

<< Example 2 >>
A joining composition was prepared and evaluated in the same manner as in Example 1 except that ricinoleic acid was removed from the dispersion medium. The results are shown in Table 1.

Example 3
A joining composition was prepared and evaluated in the same manner as in Example 1 except that ethoxyacetic acid was added instead of methoxyacetic acid. The results are shown in Table 1. The following evaluation test was also conducted.

Example 4
A joining composition was prepared and evaluated in the same manner as in Example 1 except that 3-ethoxypropionic acid was added instead of methoxyacetic acid. The results are shown in Table 1.

Example 5
A joining composition was prepared and evaluated in the same manner as in Example 1 except that levulinic acid was added instead of methoxyacetic acid. The results are shown in Table 1.

Example 6
A joining composition was prepared and evaluated in the same manner as in Example 1 except that levulinic acid was added instead of methoxyacetic acid and ricinoleic acid was removed from the dispersion medium. The results are shown in Table 1.

≪Comparative example 1≫
A joining composition was prepared and evaluated in the same manner as in Example 1 except that 3-ethoxypropylamine was added instead of methoxyacetic acid. The results are shown in Table 1.

≪Comparative example 2≫
A joining composition was prepared and evaluated in the same manner as in Example 1 except that 3-ethoxypropylamine was added instead of methoxyacetic acid and ricinoleic acid was removed from the dispersion medium. The results are shown in Table 1.

«Comparative Example 3»
A bonding composition was prepared and evaluated in the same manner as in Example 1 except that a mixture of 3-ethoxypropylamine and hexylamine (molar ratio = 1: 1) was added instead of methoxyacetic acid. The results are shown in Table 1.

<< Comparative Example 4 >>
A bonding composition was prepared in the same manner as in Example 1 except that 3-ethoxypropylamine and hexylamine mixture (molar ratio = 1: 1) was added instead of methoxyacetic acid, and ricinoleic acid was removed from the dispersion medium. Prepared and evaluated. The results are shown in Table 1.

<< Comparative Example 5 >>
A joining composition was prepared and evaluated in the same manner as in Example 1 except that 2- (2-aminoethoxy) ethanol was added instead of methoxyacetic acid and ricinoleic acid was removed from the dispersion medium. The results are shown in Table 1.

<< Comparative Example 6 >>
A joining composition was prepared and evaluated in the same manner as in Example 1 except that 2- (2-aminoethylamino) ethanol was added instead of methoxyacetic acid and ricinoleic acid was removed from the dispersion medium. . The results are shown in Table 1.

Example 7
A joining composition was prepared and evaluated in the same manner as in Example 1 except that the amount of ricinoleic acid added in the dispersion medium was 0.025 g. The results are shown in Table 2. However, the following evaluation tests 2 and 3 were also performed here using a 5 mm × 5 mm Si chip.

[Evaluation Test 2] Measurement of Void Ratio Voids of the laminate subjected to the firing treatment were evaluated with an ultrasonic flaw detector (probe 80 MHz, φ3 mm, PF = 10 mm) manufactured by Nippon Kraut Kramer Co., Ltd. Fine adjustment was made so that the reflection peak at the bonding interface was the highest, and the measurement was performed with the material sound velocity = Si: 9600 mm / s. The void ratio was set to a threshold value of 55% of the reflection intensity, and more than that was regarded as a void.

[Evaluation Test 3] High Temperature Reliability Cycle in which the laminate fired in the above [Evaluation Test 1] is placed in a thermal shock tester (manufactured by Hutec Co., Ltd.) and kept at −40 ° C. and 200 ° C. for 10 minutes respectively in the air atmosphere Were removed at any number of cycles. The case where the void ratio did not increase by 5% or more with respect to 0 cycle after 20 cycles was indicated as “◯”, and the case where the void ratio increased by 0.5% or more was indicated as “X”.

Example 8
Levulinic acid was used instead of methoxyacetic acid, the amount of ricinoleic acid added in the dispersion medium was 0.025 g, and firing was performed using an oxygen-free copper substrate without plating (1 min ultrasonic treatment in 10 wt% sulfuric acid aqueous solution). A bonding composition was prepared and evaluated in the same manner as in Example 1 except that was performed in a nitrogen atmosphere. The results are shown in Table 2.

Example 9
Except that levulinic acid was used instead of methoxyacetic acid, ricinol in the dispersion medium was changed to 0.025 g of oleic acid, and the calcination treatment was performed in a nitrogen atmosphere using an oxygen-free copper substrate without plating. A bonding composition was prepared and evaluated. The results are shown in Table 2.

<< Comparative Example 7 >>
A bonding composition was prepared and evaluated in the same manner as in Example 1 except that 3-ethoxypropylamine was used in place of methoxyacetic acid, and a non-plated oxygen-free copper substrate was used for the firing treatment in a nitrogen atmosphere. Went. The results are shown in Table 2.

It can be seen from Table 1 that if the bonding composition of the present invention is used, a bonding layer having a sufficient bonding strength with a shear strength of 40 MPa or more can be obtained without requiring pressure during firing bonding. Also, from Table 2, if the bonding composition of the present invention is used, no pressure is required during firing bonding, regardless of air firing or inert atmosphere firing, or plating-bonded substrate bonding or non-plating substrate bonding. It can be seen that a bonding layer having a low void ratio and strong bonding strength and excellent heat reliability can be obtained.

Claims

Silver nanoparticles,
A dispersion medium;
A first carboxylic acid containing an O atom in a carbon chain attached to at least a portion of the surface of the silver nanoparticles;
A bonding composition characterized by comprising:
The bonding composition according to claim 1, wherein the carboxylic acid has 5 or less carbon atoms.
The bonding composition according to claim 1 or 2, wherein the silver nanoparticles have an average primary particle size of 10 to 100 nm.
The bonding composition according to claim 1, wherein the dispersion medium contains a second carboxylic acid.
The bonding composition according to claim 4, wherein the second carboxylic acid is a monocarboxylic acid.
The bonding composition according to claim 5, wherein the second carboxylic acid is ricinoleic acid or oleic acid.
The bonding composition according to any one of claims 1 to 6, wherein the first carboxylic acid is levulinic acid, methoxyacetic acid, ethoxyacetic acid or 3-ethoxypropionic acid.
The bonding composition according to any one of claims 1 to 7, further comprising inorganic microparticles having an average particle diameter of 1 to 15 µm.
The bonding member according to any one of claims 1 to 8, wherein the first bonded member, the second bonded member, and the first bonded member and the second bonded member are bonded. And a bonding layer comprising a composition.
A first step of producing silver nanoparticles by a silver oxalate complex decomposition method,
The carboxylic acid is added to at least a part of the surface of the silver nanoparticle by heating the silver nanoparticle obtained in the first step by adding a first carboxylic acid containing an O atom to a portion other than the carboxyl group. A second step of attaching
The manufacturing method of the composition for joining characterized by including.
Silver nanoparticles,
A first carboxylic acid containing an O atom in a carbon chain attached to at least a portion of the surface of the silver nanoparticles;
Coated silver nanoparticles characterized by comprising: