JP6990411B2 - Bonding composition - Google Patents

Description

The present invention relates to a bonding composition.

Printable electronics, which do not require patterning by exposure by directly printing a dispersion liquid containing metal particles on a wiring pattern by various printing methods such as inkjet, are attracting attention.
Further, it is known that metal particles having a diameter of several tens of nm or less exhibit various physical and chemical properties different from those of bulk metals as the particle size becomes smaller. For example, it is known that the melting point of metal particles becomes lower than the melting point of bulk metal as the particle size becomes smaller. Therefore, from the viewpoint of lowering the temperature at the time of sintering, it is considered to use metal particles having a small particle diameter. Examples of the printing method include an inkjet printing method, a screen printing method, a flexographic printing method, a dispense printing method, and the like.

In Patent Document 1, the present inventors include copper nuclei particles and a plurality of aliphatic carboxylic acid molecules arranged on the surface of the copper nuclei particles at a density of 2.5 to 5.2 molecules per 1 nm ² . , Coated copper particles are disclosed. Further, in Patent Document 2, the present inventors describe silver nuclei particles and a plurality of aliphatic carboxylic acid molecules arranged on the surface of the silver nuclei particles at a density of 2.5 to 5.2 molecules per 1 nm ² . Discloses coated silver particles, including.
These coated copper particles and coated silver particles are said to have excellent oxidation resistance and sinterability.

Japanese Unexamined Patent Publication No. 2016-069716 Japanese Unexamined Patent Publication No. 2017-179403

Generally, a bonding composition containing coated metal particles forms a bonded body by heating the temperature to sinter the coated metal particles. However, the metal particles may be oxidized due to desorption of coated molecules during the sintering process. In such a case, the bonding strength of the bonded body may decrease.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a bonding composition for forming a bonded body having excellent bonding strength.

One embodiment of the bonding composition according to the present invention comprises metal powder and a plurality of aliphatic carboxylic acids (A1) and aliphatic aldehydes (A2) on the surface of metal nuclei particles having a particle size smaller than that of the metal powder. The coated metal particles (A) coated with one or more selected coated molecules at a density of 2.5 to 5.2 molecules / nm ² and an aliphatic carboxylic acid-based solvent having a boiling point of 160 ° C. or higher and 300 ° C. or lower (a). It contains B1) and one or more solvents (B) selected from an aliphatic aldehyde-based solvent (B2) having a boiling point of 160 ° C. or higher and 300 ° C. or lower.

In one embodiment of the bonding composition according to the present invention, the aliphatic aldehyde-based solvent (B2) contains decanal.

In one embodiment of the bonding composition according to the present invention, the aliphatic carboxylic acid solvent (B1) contains octanoic acid.

According to the present invention, it is possible to provide a bonding composition for forming a bonded body having excellent bonding strength.

[Composition for bonding]
The bonding composition of the present embodiment is selected from a plurality of aliphatic carboxylic acids (A1) and aliphatic aldehydes (A2) on the surface of the metal powder and the metal nuclei particles having a particle size smaller than that of the metal powder 1. Coated metal particles (A) coated with seeds or more of coated molecules at a density of 2.5 to 5.2 molecules / nm ² , and an aliphatic carboxylic acid-based solvent (B1) having a boiling point of 160 ° C. or higher and 300 ° C. or lower, and a boiling point. Contains one or more solvents (B) selected from aliphatic aldehyde-based solvents (B2) having a temperature of 160 ° C. or higher and 300 ° C. or lower.

That is, the bonding composition of the present embodiment contains a metal powder, coated metal particles (A) coated with a coated molecule having an aliphatic group, and a solvent (B) having a boiling point of 160 ° C. or higher and 300 ° C. or lower. Contains. In such a configuration, since the boiling point of the solvent (B) is 160 ° C. or higher and 300 ° C. or lower, it is difficult to volatilize, and the coated metal particles (A) and the metal powder are protected even in the sintering process, and the oxidation resistance is improved. It is presumed to improve.
From the above, the bonding composition of the present embodiment can form a bonded body having excellent bonding strength.

<Metal powder>
As the metal powder used in the present embodiment, a known metal powder used in the bonding composition can be used. The type of metal in the metal powder is not particularly limited, and one or more of the metals that can be used for the metal nucleus particles described later can be appropriately selected and used. Above all, it is preferable to use copper or silver from the viewpoint of conductivity. The mass ratio of the metal powder to the coated metal particles (A) is not particularly limited, but is preferably 20:80 to 80:20, more preferably 30:70 to 70:30, and 40: 60 to 60:40 is even more preferable.

The particle size of the metal powder used in the present embodiment is not particularly limited, but the average primary particle size of the metal powder is preferably 0.3 or more and 10 μm or less, more preferably 0.4 or more and 5 μm or less, and even more preferably 0. It can be 5.5 or more and 1.0 μm or less. By using a metal powder having an average primary particle size of 10 μm or less, the density of the metal powder in the bonding composition can be made more uniform, and the bonding strength can be improved. Further, in the present embodiment, a plurality of types of metal powders having different average primary particle sizes may be mixed and used. When multiple types of metal powders with different average primary particle sizes are mixed and used, metal powders with a relatively small average primary particle size enter between the metal powders with a relatively large average primary particle size, and the overall packing density is increased. Can be improved.

<Coated metal particles>
The coated metal particles (A) used in the present embodiment are selected from a plurality of aliphatic carboxylic acids (A1) and aliphatic aldehydes (A2) on the surface of the metal nucleus particles having a particle diameter smaller than that of the metal powder described above. Particles coated with one or more coated molecules at a density of 2.5 to 5.2 molecules / nm ² . In the coated molecule, the carboxy group side is adsorbed on the surface of the metal nucleus particle to form a monolayer. Therefore, it is presumed that the surface of the metal nuclei particles is protected by the coated molecules, oxidation is suppressed, and the metal nuclei particles have high oxidation resistance. For example, in the coated silver particles using silver nuclei particles as the metal nuclei particles, the content ratio of silver oxide and silver hydroxide after 2 months from the production is set with respect to 100% by mass of the silver nuclei particles in the coated silver particles. It is also possible to suppress it to 5% by mass or less. The formation of the metal oxide in the coated metal particles (A) can be confirmed by the X-ray diffraction (XRD) measurement of the coated metal particles (A).

Further, since the coated molecule is bound to the metal nucleus particle by physical adsorption or the like, it is considered that the coated molecule diffuses and desorbs at a relatively low temperature. Therefore, since the surface of each metal nucleus particle is easily exposed by heating and the surfaces of the metal nucleus particle can come into contact with each other, the coated metal particle (A) is excellent in sinterability at a low temperature.

(Metal nucleus particles)
The average primary particle size of the metal nuclei particles used in the present embodiment is not particularly limited as long as it is smaller than the average primary particle size of the metal powder, but it may be less than 300 nm from the viewpoint of low-temperature sinterability and dispersibility. It is more preferably 250 nm or less, and even more preferably 200 nm or less. The average primary particle size of the metal nucleus particles is usually 1 nm or more, preferably 5 nm or more, and more preferably 20 nm or more. The average primary particle size of the metal nucleus particles is an arithmetic average value of the primary particle diameters of any 20 metal nucleus particles observed by a scanning electron microscope (SEM).

The material of the metal nucleus particles may be any metal that exhibits sufficient bonding strength after sintering, for example, gold, silver, copper, platinum, aluminum, iron, chromium, tin, nickel, zinc, lead, indium, bismuth, etc. Examples include germanium, antimony, cobalt, palladium, rhodium, molybdenum, tungsten, titanium, zirconium, gallium, arsenic, boron, silicon, and alloys thereof. The material of the metal nucleus particles is preferably a metal that exhibits conductivity after sintering, more preferably gold, silver, or copper, and even more preferably silver or copper. By using these metals, for example, the bonding composition of the present embodiment can be applied to printing of electronic circuits and the like. Further, since the coated metal particles (A) used in the present embodiment are excellent in oxidation resistance, copper can be preferably used as the metal nucleus particles. When there are a plurality of coated metal particles (A), the contained metal nuclei particles may be the same as each other or may be different from each other.

The metal nucleus particles may contain metal oxides, metal hydroxides, and other impurities as long as the effects of the present invention are not impaired. The content ratio of the metal oxide and the metal hydroxide is preferably 5% by mass or less, more preferably 3% by mass or less, and 1% by mass or less with respect to the metal nucleus particles from the viewpoint of conductivity. Is even more preferable. Further, from the viewpoint of conductivity, the content ratio of the metal in the metal nucleus particles is preferably 95% by mass or more, more preferably 97% by mass or more, and further more preferably 99% by mass or more. preferable.

The shape of the metal nucleus particles can be appropriately selected depending on the intended use and the like. Examples of the shape include a substantially spherical shape including a true spherical shape, a plate shape, a rod shape, and the like, and among them, a substantially spherical shape is preferable. According to the method for producing the coated metal particles (A) described later, substantially spherical metal nuclei particles that can be approximated to a spherical shape can be obtained. The particle size of the coated metal particles (A) can be determined by SEM observation.

(Coating molecule)
As the coated molecule in the present embodiment, one or more molecules selected from the aliphatic carboxylic acid (A1) and the aliphatic aldehyde (A2) are used alone or in combination. The coated molecule coats the surface of the metal nucleus particle with a density of 2.5 to 5.2 molecules per 1 nm ² , and has a dispersibility and an oxidation suppressing effect of the metal nucleus particle. Further, at the time of sintering, the coated molecule is easily removed from the surface of the metal nucleus particle, decomposed or volatilized, so that the residue in the bonded body is suppressed. As a result, a conductor having excellent electrical conductivity can be obtained.

The boiling point of the coated molecule in the present embodiment is preferably 150 ° C. or higher, more preferably 160 ° C. or higher, and even more preferably 200 ° C. or higher. When the boiling point of the coated molecule satisfies the above condition, the coated molecule sufficiently protects the metal nuclei particles even in the sintering process, so that the oxidation resistance of the metal nuclei particles can be improved and the bonding strength can be increased. .. On the other hand, from the viewpoint of increasing the bonding strength, the boiling point of the coated molecule is preferably 300 ° C. or lower.

<< Aliphatic Carboxylic Acid >>
The aliphatic carboxylic acid (A1) is a compound having a structure in which one or two or more carboxy groups are substituted in the aliphatic compound, and in the present embodiment, the aliphatic carboxylic acid is usually formed on the surface of metal nuclei particles. The carboxy group of the acid (A1) is arranged. In the present embodiment, an aliphatic compound having a structure in which one carboxy group is substituted, that is, a compound having an aliphatic hydrocarbon group and one carboxy group is preferable.

The aliphatic hydrocarbon group constituting the aliphatic carboxylic acid (A1) is a hydrocarbon group having a linear, branched or cyclic structure, and may have an unsaturated bond. In the present embodiment, it is preferable to use a linear aliphatic hydrocarbon group having no branching or cyclic structure from the viewpoint that a monomolecular film can be easily formed on the surface of the metal nucleus particles at a predetermined density. The unsaturated bond may be a double bond or a triple bond, but is preferably a double bond. When the aliphatic hydrocarbon group has an unsaturated bond, the number thereof is preferably 1 to 3 in one molecule, more preferably 1 to 2, and even more preferably 1. preferable.

In the present embodiment, the aliphatic carboxylic acid (A1) preferably has a carboxy group at the terminal of the linear aliphatic hydrocarbon group. By forming the aliphatic hydrocarbon group into a linear structure, the affinity between the coated metal particles (A) and the solvent (B) described later can be enhanced, and the dispersibility of the coated metal particles (A) can be improved. Further, in the aliphatic carboxylic acid (A1), the number of carbon atoms of the aliphatic group is preferably 3 or more, more preferably 5 or more, and even more preferably 7 or more. When the number of carbon atoms is 3 or more, the dispersibility and oxidation resistance of the coated metal particles (A) can be improved. On the other hand, the number of carbon atoms of the aliphatic group is preferably 17 or less, more preferably 16 or less, and even more preferably 11 or less. When the number of carbon atoms is 17 or less, the coated metal particles (A) can be easily removed during sintering, and a conductor having excellent electrical conductivity can be obtained. In this embodiment, the number of carbon atoms of the aliphatic group does not include the carbon atoms constituting the carboxy group.

Specific examples of the preferred aliphatic carboxylic acid (A1) include butyric acid, caproic acid, caprylic acid, pelargonic acid, stearic acid, palmitoleic acid, oleic acid, vaccenic acid, linoleic acid, linolenic acid and the like. The aliphatic carboxylic acid (A1) can be used alone or in combination of two or more.

<< Aliphatic aldehyde >>
In the present embodiment, the aliphatic aldehyde (A2) can be arranged on the surface of the metal nucleus particles in place of the aliphatic carboxylic acid (A1) or in combination with the aliphatic carboxylic acid (A1). .. Even in this case, similarly to the aliphatic carboxylic acid (A1), the coated metal particles (A) capable of forming a conductor having excellent electrical conductivity can be obtained.

The aliphatic aldehyde (A2) is a compound having a structure in which one or more aldehyde groups are substituted in the aliphatic compound. The aliphatic aldehyde (A2) used in the present embodiment is preferably a compound having a structure in which one aldehyde group is substituted for the aliphatic compound, that is, a compound having an aliphatic hydrocarbon group and one aldehyde group. In the present embodiment, the aldehyde group of the aliphatic aldehyde (A2) is usually arranged on the surface of the metal nucleus particles. By arranging the aldehyde group on the surface of the metal nuclei particles, the reducing action of the aliphatic aldehyde (A2) can suppress the oxidation of the surface of the metal nuclei particles and obtain the cleaning effect of pollutants. Further, it is presumed that the arrangement of the aldehyde group on the surface of the metal nucleus particles has the effect of removing foreign substances and oxides on the surface of the base material.

As the aliphatic hydrocarbon group constituting the aliphatic aldehyde (A2), the same one as that of the aliphatic carboxylic acid (A1) can be selected.
Specific examples of the preferred aliphatic aldehyde (A2) include butyraldehyde, hexyl aldehyde, octyl aldehyde, nonanal aldehyde, octadecyl aldehyde, hexadecenyl aldehyde and the like. The aliphatic aldehyde (A2) can be used alone or in combination of two or more.

The surface of the metal nucleus particles is coated with one or more coating molecules selected from a plurality of aliphatic carboxylic acids (A1) and aliphatic aldehydes (A2) at a density of 2.5 to 5.2 molecules / nm ² . ing. That is, the surface of the metal nucleus particles is coated with a coating layer containing a coating molecule, and the coating density is 2.5 to 5.2 molecules / nm ² . From the viewpoint of dispersibility and oxidation resistance, the coating density is preferably 3.0 to 5.2 molecules / nm ² , and more preferably 3.5 to 5.2 molecules / nm ² .

The coating density of the coated molecule on the surface of the metal nucleus particle can be calculated as follows. For the coated metal particles (A), the organic component adhering to the surface is extracted by liquid chromatography (LC) according to the method described in JP2012-88242, and the component analysis is performed. In addition, TG-DTA measurement (thermogravimetric measurement / differential thermal analysis) is performed to measure the amount of organic components contained in the coated metal particles (A). Next, the amount of the coated molecule contained in the coated metal particle (A) is calculated together with the analysis result of LC. In addition, the average primary particle diameter of the metal nucleus particles is measured by observing the SEM image.
From the above analysis results, the number of molecules of the coated molecule contained in 1 g of the coated metal particle (A) is represented by the following formula (a).
[Number of molecules of coated molecule] = MA / ( _{M w} / _NA ) ... (a)
Here, MA is the mass (g) of the coated molecule contained in 1 g of the coated metal particles ( _A ), M _w is the molecular weight of the coated molecule, and _NA is the Avogadro constant. When two or more kinds of coated molecules are included, the number of molecules is calculated for each component and totaled.
The shape of the metal nucleus particles is approximated to a sphere, and the mass MB (g) of the metal nucleus particles is obtained by subtracting the amount of organic components from the mass of the coated metal particles ( _A ). The number of metal nucleus particles in 1 g of the coated metal particles (A) is represented by the following formula (b).
[Number of metal nuclei particles] = MB / [( _4πr ^3/3 ) × d × ^10-21 ] ・ ・ ・ (b)
Here, MB is the mass (g) of the metal particles contained in 1 g of the coated metal particles ( _A ), r is the radius (nm) of the primary particle diameter calculated by SEM image observation, and d is the density of the metal. (G / cm ³ ) (d = 8.94 for copper). The surface area of the metal nucleus particles contained in 1 g of the coated metal particles (A) is represented by the following formula (c) from the formula (b).
[Surface area of metal nuclei particles (nm ² )] = [Number of metal nuclei particles] × 4πr ² ... (c)
From the above, the coating density (molecule / nm ² ) of the metal particles by the coating molecule is calculated by the following equation (d) using the equations (a) and (c).
[Coating density] = [Number of coated molecules] / [Surface area of metal nuclei particles] ... (d)

The bonding state between the coated molecule and the metal nucleus particle in the coated metal particle (A) may be an ionic bond or a physical adsorption. From the viewpoint of the sinterability of the coated metal particles (A), the coated molecule is preferably physically adsorbed on the surface of the metal nuclei particles, and is physically adsorbed on the surface of the metal nuclei particles with a carboxy group or an aldehyde group. It is preferable to have.

It can be confirmed by analyzing the surface composition of the coated metal particles (A) that the coated molecules are physically adsorbed on the metal nuclei particles. Specifically, time-of-flight secondary ion mass spectrometry (ToF-SIMS) surface analysis was performed on the coated metal particles (A), and substantially only free coated molecules were detected and bonded to metal atoms. It can be confirmed that the coated molecule is not substantially detected. Here, the fact that the coated molecule bonded to the metal atom is not substantially detected means that the signal amount of the coated molecule attached to the metal nuclei particle is 5% or less of the signal amount of the free coated molecule. It means that there is, and it is preferable that it is 1% or less.

Further, the fact that the coated molecule is physically adsorbed on the surface of the metal particle with a carboxy group or an aldehyde group means that the coated metal particle (A) is subjected to infrared absorption spectrum measurement, and is substantially CO-metal. It can be confirmed that only the expansion / contraction vibration peak derived from the salt is observed, and the expansion / contraction vibration peak derived from the free carboxylic acid or the like is not substantially observed.

The particle size of the coated metal particles (A) can be appropriately selected depending on the intended use and the like. The average primary particle diameter of the coated metal particles (A) is preferably 0.02 μm or more and 5 μm or less, and more preferably 0.05 μm or more and 5 μm or less, from the viewpoint of dispersibility, conductivity, and crack suppression. , 0.07 μm or more and 2.5 μm or less is even more preferable.
The average primary particle diameter of the coated metal particles (A) is calculated as an arithmetic mean value D _SEM of the primary particle diameters of any 20 coated metal particles (A) by SEM observation.
The value of the coefficient of variation (standard deviation SD / average primary particle diameter D _SEM ) of the particle size distribution of the coated metal particles (A) is, for example, 0.01 to 0.5, preferably 0.05 to 0.3. .. In particular, since it is manufactured by the method for manufacturing the coated metal particles (A) described later, the coefficient of variation of the particle size distribution is small and the particle diameters can be made uniform. Since the coefficient of variation of the particle size distribution of the coated metal particles (A) is small, it is possible to obtain a highly dispersible dispersion with excellent dispersibility.

The coated metal particles (A) used in the present embodiment are excellent in oxidation resistance and sinterability, and the obtained bonded body exhibits high bonding strength and electrical conductivity. Therefore, it can be suitably used for a bonding composition that is printed on a substrate to form a wiring pattern or the like.

The ratio of the coated metal particles (A) contained in the bonding composition of the present embodiment is not particularly limited, but can be appropriately changed depending on the intended use. For example, in the case of screen printing, the ratio of the coated metal particles (A) to the total amount of the bonding composition can be 5 to 95% by mass, and in the case of inkjet printing, the coated metal particles (A) to the total amount can be set. ) Can be 40 to 90% by mass.

<Manufacturing method of coated metal particles>
The coated metal particles (A) used in the present embodiment are selected from the above-mentioned metal carboxylic acid salt containing a metal to be a specific metal nucleus particle, and the above-mentioned specific aliphatic carboxylic acid (A1) and aliphatic aldehyde (A2). It is manufactured using one or more of the following molecules. For example, it can be manufactured with reference to the description in paragraphs 0031 to 0066 of Patent Document 1 and paragraph 805 and the like. Alternatively, it can be manufactured with reference to the descriptions in paragraphs 0052 to 0101 and 0110 to 0114 of Patent Document 2.
In a preferred method for producing the coated metal particles (A), a reaction solution containing a metal carboxylate, a coated molecule, and a medium is prepared, and the complex compound produced in the reaction solution is thermally decomposed to cause a metal nucleus. It is possible to obtain coated metal particles (A) in which the surface of the particles is coated with a coating molecule at a density of 2.5 to 5.2 molecules per 1 nm ² .

The carboxylic acid in the metal carboxylate can be appropriately selected from the viewpoint of the type of metal, the ease of producing the metal carboxylate, and the like. Examples of the carboxylic acid used include formic acid, oxalic acid, citric acid and the like. Further, depending on the type of metal, carbonic acid may be used instead of the carboxylic acid. When copper is used as the metal, it is preferable to use copper formate as the metal carboxylate. When silver is used as the metal, silver formate, silver oxalate, silver carbonate, silver citrate, etc. can be used as the metal carboxylate. Among them, silver oxalate is used because the thermal decomposition temperature is high. It is preferable to use it. The metal constituting the metal carboxylate can be the same as that of the metal nucleus particles.

It is preferable that the reaction solution contains an amino alcohol that can be complexed with the metal carboxylate. The complex formation of the metal carboxylate and the amino alcohol improves the solubility in the medium described later.
The amino alcohol may be an alcohol compound having at least one amino group. The amino alcohol is preferably a mono-amino monoalcohol compound, and more preferably a mono-amino monoalcohol compound in which the amino group is unsubstituted. It is also preferable that the amino alcohol is a mono-amino monoalcohol compound having a monodentate coordination. Specific examples of preferable amino alcohols include 2-aminoethanol, 3-amino-1-propanol, 5-amino-1-pentanol, DL-1-amino-2-propanol, N-methyldiethanolamine and the like.

The medium constituting the reaction solution can be appropriately selected and used from those that do not inhibit the reduction of the metal of the metal carboxylate. The medium is usually an organic solvent. The medium has at least a main medium having low compatibility with amino alcohol, and may have an auxiliary medium compatible with amino alcohol, if necessary.

Preferred main media include ethylcyclohexane, C9-based cyclohexane [manufactured by Maruzen Petroleum, trade name: Swaclean # 150], n-octane and the like. The medium can be used alone or in combination of two or more.
Preferred auxiliary mediums include glycol ethers such as EO (ethylene oxide) -based glycol ethers, PO (propylene oxide) -based glycol ethers, and dialkyl glycol ethers.
The main medium and the auxiliary medium can be used independently or in combination of two or more.

The complex compound generated in the reaction solution preferably contains a metal ion and a carboxylic acid and an amino alcohol as ligands. By including amino alcohol as a ligand, the thermal decomposition temperature of the complex compound is lowered.
The complex compound produced in the reaction solution produces a metal reduced by the thermal decomposition treatment. The temperature of the thermal decomposition treatment may be appropriately adjusted in consideration of the thermal decomposition temperature of the complex compound coordinated with the amino alcohol as described above. By setting the temperature of the thermal decomposition treatment low, the formation of acid amide due to the dehydration reaction between the coated molecule and the amino alcohol is suppressed, and the detergency of the obtained coated metal particles (A) tends to be improved.

The reduced metal is generated and grown by the thermal decomposition treatment of the complex compound, and the coating molecules present in the reaction solution are adsorbed on the surface of the obtained metal nuclei particles, so that the surface is coated with the coating molecules. Metal particles (A) are obtained. The adsorption of the coated molecule on the surface of the metal nucleus particles is preferably physical adsorption. This improves the sinterability of the coated metal particles (A). By suppressing the formation of metal oxides in the thermal decomposition treatment of complex compounds, the physical adsorption of coated molecules is promoted.

In the method for producing the coated metal particles (A), as factors that control the particle size distribution of the coated metal particles (A) to be produced, for example, the type and addition amount of the coated molecule, the concentration of the metal carboxylate, and the ratio of the medium ( It is determined by the main medium / auxiliary medium), etc. The factor that controls the size of the coated metal particles (A) is to appropriately maintain the heating rate that controls the number of metal nuclei generated, that is, the stirring rate that is related to the amount of heat input to the reaction system and the size of the micro reaction field. Can be aligned.

<Solvent>
The solvent (B) used in the present embodiment is selected from an aliphatic carboxylic acid solvent (B1) having a boiling point of 160 ° C. or higher and 300 ° C. or lower and an aliphatic aldehyde solvent (B2) having a boiling point of 160 ° C. or higher and 300 ° C. or lower. Includes one or more species that are to be used. The solvent (B) is a liquid at 25 ° C. and 1 atm.

The boiling point of the solvent (B) may be 160 ° C. or higher, but it is preferably 200 ° C. or higher from the viewpoint of remaining in the bonding composition during the sintering process to protect the coated metal particles (A). The boiling point of the solvent (B) may be 300 ° C. or lower, but is preferably 280 ° C. or lower from the viewpoint of suppressing the residue after sintering and increasing the bonding strength and conductivity of the bonded body. More preferably, it is below ° C.

The aliphatic group of the solvent (B) preferably has a linear, branched or cyclic structure. In the present embodiment, the aliphatic group of the solvent (B) is a linear aliphatic hydrocarbon group having no branching or cyclic structure because it easily interacts with the coated molecule of the coated metal particles (A). It is preferable to have. Further, the solvent (B) may have a double bond or a triple bond as an unsaturated bond, but has an unsaturated bond because it easily interacts with the coated molecule of the coated metal particles (A). It is preferable not to do so. When the aliphatic hydrocarbon group has an unsaturated bond, the unsaturated bond is preferably a double bond. The number thereof is preferably 1 to 3 in one molecule, more preferably 1 to 2, and even more preferably 1.

The number of carbon atoms of the aliphatic group of the solvent (B) is not particularly limited, but is preferably 3 or more, preferably 5 or more, and even more preferably 6 or more. When the number of carbon atoms of the aliphatic group of the solvent (B) satisfies the above conditions, the compatibility of the coated metal particles (A) with the coated molecule is excellent. Therefore, the protection of the coated metal particles (A) can be further enhanced. Further, as will be described later, when the number of carbon atoms of the aliphatic group of the solvent (B) satisfies the above condition, a hydrocarbon-based solvent having high compatibility is included as another solvent to obtain the coated metal particles (A). The oxidation resistance can be further improved.

The solvent (B) contains one or more selected from the above-mentioned aliphatic carboxylic acid-based solvent (B1) and aliphatic aldehyde-based solvent (B2), and among them, it is selected from the aliphatic aldehyde-based solvent (B2). It is preferable to include one or more of them. By containing a reducing aliphatic aldehyde-based solvent (B2) in the bonding composition, oxidation of the coated metal particles due to oxygen in the air or the like is suppressed, and the chemical stability of the coated metal particles is further enhanced. Can be done.

When an aliphatic aldehyde-based solvent (B2) is used as the solvent (B), it is preferably selected from, for example, octanal, decanal, dodecanal, tridecanal, and a mixture thereof, and in particular, the acid resistance of the coated metal particles (A). From the viewpoint of improving the chemical properties, it is preferable to select from decanal, dodecanal and a mixture thereof, and it is more preferable to use decanal.

When an aliphatic carboxylic acid-based solvent (B1) is used as the solvent (B), it is preferably selected from, for example, caproic acid, hepanoic acid, octanoic acid, nonanoic acid, and a mixture thereof, and in particular, a coating metal. From the viewpoint of compatibility with the particle (A), it is preferable to select from octanoic acid, nonanoic acid, and a mixture thereof, and it is more preferable to use octanoic acid.

The ratio of the solvent (B) contained in the bonding composition of the present embodiment is not particularly limited, but can be, for example, 0.1% by mass or more and 95% by mass or less, and 0.2% by mass or more and 90% by mass. % Or less, and even more preferably 0.4% by mass or more and 80% by mass or less.

<Other ingredients>
The bonding composition according to the present invention contains the above-mentioned metal powder, coated metal particles (A), and solvent (B), and is necessary as long as the effects of the present invention are not impaired. Further, other components may be contained. Examples of other components include other solvents different from the solvent (B), antioxidants, dispersants, thickeners, gelling agents and the like. By combining a solvent, a dispersant, and a thickener, for example, the rheological properties of the bonding composition can be adjusted.

The viscosity of the mixture of other solvents, antioxidants, dispersants, thickeners, and gelling agents may be appropriately adjusted according to the printing means and the like. For example, the viscosity at 25 ° C. and 10 rpm can be appropriately adjusted in the range of 0.01 Pa · s or more and 500 Pa · s or less, and preferably 0.01 Pa · s or more and 50 Pa · s or less.

(Other solvents)
As another solvent that can be contained in the bonding composition according to the present embodiment, a solvent having high compatibility with the solvent (B) is used. Examples of the other solvent include a hydrocarbon solvent, a halogenated hydrocarbon solvent, an alcohol solvent, an ether solvent, an ester solvent, a ketone solvent, an amide solvent, a sulfonic acid solvent, and a carbon number of carbon atoms. Examples thereof include an aromatic carboxylic acid solvent or an aldehyde solvent having less than 8 or having more than 12 carbon atoms, and one or a mixture of two or more selected from these can be used. Above all, from the viewpoint of improving the dispersibility of the metal powder and the coated metal particles (A), it is preferable to use one or a mixture of two or more selected from the hydrocarbon solvents, and it is particularly preferable to use liquid paraffin. ..
When the bonding composition according to the present embodiment contains another solvent, the ratio of the other solvent is not particularly limited, but may be, for example, 0.1% by mass or more and 95% by mass or less.

<< Liquid paraffin >>
When liquid paraffin is used in the bonding composition of the present embodiment, the liquid paraffin is a mixture of aliphatic hydrocarbons having a linear, branched or cyclic structure, and is preferably liquid at room temperature.
Since the surface of the coated metal particles (A) is covered with hydrophobic groups, it has excellent compatibility with liquid paraffin. Therefore, the coated metal particles (A) can be dispersed in the liquid paraffin in a stable state for a long time. Further, since liquid paraffin is chemically stable, it is difficult to react with the coated metal particles (A) and metal powder. Therefore, the oxidation of the coated metal particles (A) and the metal powder in the bonding composition is suppressed.
Liquid paraffin also exhibits good dispersibility with respect to the metal powder.

In addition, liquid paraffin is a mixture of aliphatic hydrocarbons having different molecular weights, and has a range of vaporization temperatures. That is, when the liquid paraffin in the present embodiment is heated, it gradually starts to volatilize after exceeding a certain temperature, and by further raising the temperature, almost all of the liquid paraffin can be volatilized. The temperature at which the liquid paraffin begins to volatilize is preferably higher than normal temperature and lower than the sintering temperature of the coated metal particles (A). Further, the temperature at which all the liquid paraffin volatilizes is preferably higher than the sintering temperature of the coated metal particles (A) and the boiling point of the solvent (B). For example, liquid paraffin having a vaporization temperature in the range of 50 ° C to 350 ° C can be used.
Under such conditions, when the bonding composition according to the present invention is heated, the liquid paraffin is gradually vaporized, so that the concentrations of the coated metal particles (A) and the metal powder are gradually increased. Further, since the liquid paraffin remains even after the solvent (B) has volatilized, the oxidation resistance of the coated metal particles (A) can be further improved and the bonding strength of the sintered body can be increased. Therefore, the coated metal particles (A) can be sintered in a state of having a high density, and a stronger bonded body can be formed.

The density of the liquid paraffin is not particularly limited, but is preferably 0.80 g / cm ³ or more, more preferably 0.82 g / cm ³ or more, and 0.83 g / cm ³ or more at 15 ° C. Is even more preferable. Liquid paraffin having the above density has a large molecular weight and tends to be difficult to volatilize. Such liquid paraffin can remain without drying even if it is left for a long time in a state of being applied to a substrate, for example. Therefore, it is easy to handle in a process such as screen printing, and can be suitably used as a material for conductive ink. The density of the liquid paraffin is preferably 0.90 g / cm ³ or less at 15 ° C., more preferably 0.88 g / cm ³ or less, and further preferably 0.87 g / cm ³ or less. More preferred. Liquid paraffin having the above density tends to volatilize at a relatively low temperature, and therefore tends to be difficult to remain in the bonded body. Therefore, the bonding composition using the liquid paraffin has high bonding strength and can form a bonded body having high thermal conductivity and electrical conductivity.

The kinematic viscosity of the liquid paraffin is not particularly limited, but is preferably 4 mm ² / s or more at 37.8 ° C., more preferably 5 mm ² / s or more, and further preferably 10 mm ² / s or more. More preferred. In the liquid paraffin having the above kinematic viscosity, the coated metal particles and the metal powder are difficult to precipitate, so that the liquid paraffin tends to show good dispersibility. The kinematic viscosity of the liquid paraffin is preferably 100 mm ² / s or less at 37.8 ° C., more preferably 90 mm ² / s or less, and even more preferably 40 mm ² / s or less. Since the liquid paraffin having the above kinematic viscosity tends to volatilize at a relatively low temperature, it tends to be difficult to remain in the bonded body. Therefore, the bonding composition using the liquid paraffin has high bonding strength and can form a bonded body having high thermal conductivity and electrical conductivity.

Examples of the liquid paraffin satisfying the above conditions include liquid paraffins of the Hi-Col K (manufactured by Kaneda Co., Ltd.) series. Among them, it is preferable to use Hi-Call K-160, Hi-Call K-230, Hi-Call K-290, and Hi-Call K-350 (all manufactured by Kaneda Co., Ltd.), and Hi-Call K-230 and Hi-Call K-290 (all are manufactured by Kaneda Co., Ltd.). It is particularly preferable to use (manufactured by).

The type of liquid paraffin can be appropriately selected depending on the combination with the coated metal particles (A) to be dispersed. For example, when the aliphatic hydrocarbon group of the coated metal particles (A) is relatively long and the sintering temperature of the coated metal particles (A) is relatively high, it is preferable to use liquid paraffin having a relatively high kinematic viscosity. .. When such liquid paraffin is used, the coated metal particles (A) are sintered while being dispersed in the liquid paraffin, so that a more uniform and high-strength bonded body can be formed. On the other hand, when the aliphatic hydrocarbon group of the coated metal particles (A) is relatively short and the sintering temperature of the coated metal particles (A) is relatively short, it is preferable to use liquid paraffin having a relatively short kinematic viscosity. .. When such liquid paraffin is used, the liquid paraffin can be volatilized at a relatively low temperature, so that a bonded body can be formed more efficiently.

When the bonding composition of the present embodiment contains liquid paraffin, the content ratio of the liquid paraffin to the coated metal particles (A) is not particularly limited, but is preferably 0.1% by mass or more, and is preferably 1% by mass or more. Is more preferable. Under such conditions, the coated metal particles (A) are well dispersed by the liquid paraffin. The content ratio of the liquid paraffin to the coated metal particles (A) is preferably 50% by mass or less, more preferably 30% by mass or less. Under such conditions, the concentration of the coated metal particles (A) is sufficiently maintained, so that high bonding strength can be realized.

(Antioxidant)
The bonding composition according to the present embodiment may contain an antioxidant for the purpose of suppressing the oxidation of the coated metal particles (A). Examples of the antioxidant include phenolic antioxidants such as tocopherols and hydroquinones, phosphorus-based antioxidants, sulfur-based antioxidants, amine-based antioxidants, and the like, which are selected from these. It is preferable to use one kind or a mixture of two or more kinds, and it is more preferable to use a phenolic antioxidant from the viewpoint of compatibility with the solvent (B), and even more preferably tocopherol.

The ratio of the antioxidant contained in the bonding composition of the present embodiment is not particularly limited, but is preferably 0.0001% by mass to 20% by mass with respect to 100% by mass of liquid paraffin, for example, 0. It is more preferably 0005% by mass to 20% by mass, and even more preferably 0.0005% by mass to 10% by mass.

(Dispersant)
The bonding composition according to the present embodiment may contain a known dispersant such as a polyester-based dispersant or a polyacrylic acid-based dispersant. However, from the viewpoint of maintaining the bonding strength, the content of the dispersant contained in the bonding composition is preferably 0.3% by mass or less of the total amount, and more preferably 0.1% by mass or less of the total amount. It is even more preferable that the dispersant is not substantially contained. The term "substantially free of the dispersant" means, for example, that the dispersant is 0.01% by mass or less of the total amount, and preferably is not more than the detection limit in the gel permeation chromatography measurement.

(Thickening agent / gelling agent)
The bonding composition according to the present embodiment may contain a known thickener such as a polymethacrylic acid-based thickener.
Further, when the bonding composition according to the present embodiment contains liquid paraffin, the purpose is to improve the performance of retaining the pattern shape of the coating film before sintering (hereinafter, may be referred to as "pattern retention"). Therefore, a gelling agent that gels the liquid paraffin may be contained. Examples of the gelling agent include polyolefins such as polyethylene, polypropylene, polybutylene, polyisobutylene, and polymethylpentene, and it is preferable to use one or a mixture of two or more selected from these, particularly polyethylene. It is more preferable to use it. The weight average molecular weight of the polyolefin is not particularly limited, but can be appropriately selected from, for example, 10,000 or more, preferably 10,000 to 5,000,000, preferably 20,000 to 3,000. 000 is more preferable.

When the bonding composition contains a gelling agent, it is preferable that the mixture of the liquid paraffin and the gelling agent has thixotropic properties from the viewpoint of enhancing the pattern retention. The thixotropic ratio of the mixture of liquid paraffin and the gelling agent at 25 ° C. is preferably 1.2 or more, more preferably 1.5 or more, and even more preferably 2.0 or more.
The thixotropy of the mixture of liquid paraffin and the gelling agent is the ratio of the viscosities measured at different rotation speeds with an E-type viscometer, and is calculated as (viscosity at 10 rpm) / (viscosity at 100 rpm).
Further, the blending ratio of the liquid paraffin and the gelling agent may be appropriately adjusted within a range in which desired physical properties can be obtained. When the bonding composition contains a gelling agent, from the viewpoint of improving the pattern retention, the gelling agent is 0. It is preferably 5% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, and further preferably 1.5% by mass or more and 12% by mass or less.

[Use of bonding composition]
Since the bonding composition of the present invention forms a bonded body having excellent bonding strength, it can be used for bonding a plurality of objects to be bonded. Further, since the bonded body is also excellent in conductivity, it can be used, for example, for electrically bonding a base material and an element. Further, since the bonding composition of the present invention is non-volatile at room temperature, drying is suppressed even if it is left in a state of being applied on a substrate, for example. That is, the bonding composition of the present invention is easy to handle in a process such as screen printing, and can be suitably used as a conductive ink.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.

<SEM image observation>
Measuring device: FE-EPMA JXA-8500F manufactured by JEOL
Measurement conditions: Acceleration voltage 15-20kV
Observation magnification x 1,500- x 30,000

<Calculation of average primary particle size and volatility>
Measuring device: FE-EPMA JXA-8500F manufactured by JEOL
Average primary particle size: Average value of 20 samples Volatility: Value calculated by standard deviation / mean value of 20 samples

<Thermogravimetric / differential thermal (TG-DTA) analysis>
Measuring device: TG8120 manufactured by Rigaku
Temperature rise rate: 10 ° C / min
Measurement temperature range: 25-500 ° C
Measurement atmosphere: Nitrogen (250 ml / min)

<Powder X-ray diffraction (XRD) analysis>
Measuring device: Rigaku Smartlab
Tube voltage: 45kV
Tube current: 200mA

[Manufacturing of coated metal particles and bonding composition]
(Production Example 1) Production of coated copper particles Cu1 A 3000 mL glass four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen introduction tube was installed in an oil bath at 150 ° C.
In the above flask, 484 g (3.1 mol) of formic acid anhydride, 98 g (0.2 equivalent / copper formic acid anhydride) of capric acid (manufactured by Kanto Chemical Co., Ltd.), and tripropylene as a medium (auxiliary medium). Glycolmonomethyl ether (manufactured by Tokyo Kasei Kogyo Co., Ltd.) 150 g (0.2 equivalent / copper anhydride) and petroleum-based hydrocarbon (C9 alkylcyclohexane mixture) as a medium (main medium) (Gordo Co., Ltd. "Swaclean 150" ”) 562 g (1.4 equivalents / copper anhydride) was charged. Under a nitrogen atmosphere, the contents in the flask were heated with an oil bath and mixed while stirring until the liquid temperature reached 50 ° C.
To the above mixture, 712 g (3.0 equivalent / copper anhydride) of 3-amino-1-propanol (manufactured by Tokyo Chemical Industry Co., Ltd.) was slowly added dropwise as a complexing agent. After completion of the dropping, the contents of the flask were heated in an oil bath and mixed while stirring until the liquid temperature became around 120 ° C. As the liquid temperature increased, the reaction liquid changed from dark blue to brown, and carbon dioxide gas foamed. The oil bath temperature control was stopped at the time when the foaming of carbon dioxide gas subsided, and the oil bath was naturally cooled to room temperature.
To the above reaction solution cooled to room temperature, 1200 g of methanol (manufactured by Kanto Chemical Co., Inc.) was added and mixed. The obtained mixed solution was allowed to stand for 30 minutes or more, and then the supernatant was decanted to obtain a precipitate. To the above precipitate, 1200 g of methanol (manufactured by Kanto Chemical Co., Inc.) and 390 g of acetone (manufactured by Kanto Chemical Co., Inc.) were added and mixed. The obtained mixed solution was allowed to stand for 30 minutes or more, and then the supernatant was decanted to obtain a precipitate. These operations (addition of methanol and acetone and decantation) were repeated once more.
The obtained precipitate was transferred to a 500 mL eggplant flask using 400 g of methanol (manufactured by Kanto Chemical Co., Inc.). After allowing this to stand for 30 minutes or more, the supernatant liquid was decanted.
To the obtained precipitate, 18 g of 3-hydroxy-2,2,4-trimethylpentyl isobutyric acid was added and mixed. Then, the eggplant flask was placed on a rotary evaporator, and the contents were vacuum dried (vacuum dried). After drying under reduced pressure (vacuum drying), the eggplant flask was naturally cooled to room temperature, and then the pressure was released while replacing the inside of the eggplant flask with nitrogen. As described above, 200 g of coated copper particles Cu1 having a brown viscous body was obtained.

(Production Example 2) Production of Coated Copper Particles Cu2 Production Example except that caprylic acid was changed to 68 g of lauric acid (manufactured by Kanto Chemical Co., Inc.) (0.1 equivalent with respect to copper anhydrate). In the same manner as in No. 1, 200 g of coated copper particles Cu2 having a brown viscous body was obtained.

(Production Example 3) Production of coated copper particles Cu3 In Production Example 1, the amount of capric acid is 31.8 g, the amount of petroleum hydrocarbon (Swaclean 150) is 279 g, and the amount of tripropylene glycol monomethyl ether is 74. 200 g of brown viscous coated copper particles Cu3 were obtained in the same manner as in Production Example 1 except that the amount of 3-amino-1-propanol was changed to 354 g.

(Production Example 4) Production of coated silver particles Ag1 A 300 mL glass eggplant flask equipped with a stirrer bar, a thermometer, and a reflux condenser was installed in an oil bath at 100 ° C.
In the above flask, 30 g (0.1 mol) of silver oxalate anhydride, 6 g (0.3 equivalent / silver oxalate anhydride) of undecanoic acid (manufactured by Kanto Chemical Co., Ltd.), and as a medium (auxiliary medium). Tripropylene glycol monomethyl ether (manufactured by Tokyo Kasei Kogyo Co., Ltd.) 10 g (0.5 equivalent / silver oxalate anhydride) and petroleum-based hydrocarbon (C9 alkylcyclohexane mixture) as a medium (main medium) (manufactured by Gordo) Swaclean 150 ") 54 g (4.3 equivalents / silver oxalate anhydride) was charged. Under a nitrogen atmosphere, the contents in the flask were heated with an oil bath and mixed with stirring until the liquid temperature reached 50 ° C.
To the above mixture, 52 g (7.0 equivalent / silver oxalate anhydride) of 3-amino-1-propanol (manufactured by Tokyo Chemical Industry Co., Ltd.) was slowly added dropwise as a complexing agent. After completion of the dropping, the contents of the flask were heated in an oil bath, mixed with stirring until the liquid temperature became around 85 ° C., and further heating and stirring at this temperature was continued. Three hours after the completion of the dropping, the heating of the oil bath was stopped to complete the reaction, and the reaction solution was naturally cooled to room temperature.
To the above reaction solution cooled to room temperature, 160 g of methanol (manufactured by Kanto Chemical Co., Inc.) was added and mixed. The obtained mixed solution was allowed to stand for 30 minutes or more, and then the supernatant was decanted to obtain a precipitate. To the above precipitate, 80 g of methanol (manufactured by Kanto Chemical Co., Inc.) and 80 g of acetone (manufactured by Kanto Chemical Co., Inc.) were added and mixed. The obtained mixed solution was allowed to stand for 30 minutes or more, and then the supernatant was decanted to obtain a precipitate. These operations (addition of methanol and acetone and decantation) were repeated once more.
To the obtained precipitate, 80 g of methanol (manufactured by Kanto Chemical Co., Inc.) and 1.7 g of 3-hydroxy-2,2,4-trimethylpentyl isobutyric acid were added and mixed. This was placed in an eggplant flask, placed on a rotary evaporator, and the contents were vacuum dried (vacuum dried). After drying under reduced pressure (vacuum drying), the eggplant flask was naturally cooled to room temperature, and then the pressure was released while replacing the inside of the eggplant flask with nitrogen. As described above, 18 g of silver-coated silver particles Ag1 were obtained.

(Evaluation of coated metal particles)
The physical properties of the coated metal particles were evaluated by TG-DTA analysis, XRD analysis, and SEM image observation.

(Example 1)
First, 0.4 parts by mass of liquid paraffin (Hicol K-230: manufactured by Kaneda Co., Ltd.) and 0.05 parts by mass of n-decalal (manufactured by Tokyo Kasei Co., Ltd.) are mixed and stirred with a stirrer (Awatori Rentaro). (ARE-310): manufactured by Shinky Co., Ltd.) was stirred at a rotation speed of 2000 rpm for 30 seconds.
Next, 4 parts by mass of copper powder (1050Y: manufactured by Mitsui Mining & Smelting Co., Ltd.) having an average particle diameter of 0.5 μm was blended, and stirring was performed twice for 30 seconds at a rotation speed of 2000 rpm using the above stirrer.
Next, 5.4 parts by mass of the coated metal particles (coated copper particles Cu1 obtained in Production Example 1) and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (Kyowanol M: KH) were added. (Manufactured by Neochem Co., Ltd.) 0.6 parts by mass was mixed, and stirring was performed 3 times for 30 seconds at a rotation speed of 2000 rpm using the above-mentioned stirrer.
Next, a nylon mesh with a spread of 15 μm was spread on a container (Nanko Black 160 ml: manufactured by Kinki Container Co., Ltd.), the stirred mixture was placed on the mesh, and then the stirring was used at a rotation speed of 2000 rpm to 15 Stir for seconds and mesh filtration was performed. As described above, the bonding composition of Example 1 was obtained. The obtained bonding composition was excellent in dispersibility.

(Examples 2 to 4)
The bonding compositions of Examples 2 to 4 were obtained in the same manner as in Example 1 except that the components and the blending amounts were changed as shown in Table 1 below. The obtained bonding composition was excellent in dispersibility.
The "copper powder (0.2 μm)" in Table 1 is a copper powder (1020Y: manufactured by Mitsui Mining & Smelting Co., Ltd.) having an average particle diameter of 0.2 μm.
Further, Hicol K-230 and Hicol K-290 (both manufactured by Kaneda Co., Ltd.) in Table 1 contain 99.9995% by mass of liquid paraffin and 0.0005% by mass of tocopherol, respectively. The density of Hi-Col K-230 is 0.835 to 0.855 g / cm ³ at 15 ° C, and the kinematic viscosity is 11.7 to 15.7 mm ² / s at 37.8 ° C. The density of Hicol K-290 is 0.850 to 0.865 g / cm ³ at 15 ° C, and the kinematic viscosity is 159.2 to 175 mm ² / s at 37.8 ° C.

(Examples 5 and 9)
When 0.6 parts by mass of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate is blended, 0.25 parts by mass of n-decanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) is blended together. The bonding compositions of Examples 5 and 9 were obtained in the same procedure as in Example 1. The obtained bonding composition was excellent in dispersibility.

(Example 6)
The bonding composition of Example 6 was prepared in the same procedure as in Example 5 except that 0.05 parts by mass of n-dodecanal (manufactured by Tokyo Kasei Co., Ltd.) was blended in place of 0.05 parts by mass of n-decanal. Got The obtained bonding composition was excellent in dispersibility.

(Example 7)
Joining Example 7 in the same procedure as in Example 5 except that 0.05 parts by mass of octanoic acid (Lunac 8-98: manufactured by Kao Corporation) was blended in place of 0.05 parts by mass of n-decanal. The composition for use was obtained. The obtained bonding composition was excellent in dispersibility.

(Example 8)
When blending 0.6 parts by mass of 2,2,4-trimethyl-1,3-pentanediol monoisobutylate without blending liquid paraffin, 0.5 parts by mass of butyl carbitol (manufactured by Gordo Co., Ltd.) was added. The bonding composition of Example 8 was obtained by the same procedure as in Example 5 except that it was further blended. The obtained bonding composition was excellent in dispersibility.

(Example 10)
The procedure was the same as in Example 1 except that the coated silver particles Ag1 were used instead of the coated copper particles Cu1 and silver powder having an average particle diameter of 1 μm (SL01: manufactured by Mitsui Mining & Smelting Co., Ltd.) was used instead of the copper powder. The bonding composition of Example 10 was obtained. The obtained bonding composition was excellent in dispersibility.

(Example 11)
The bonding composition of Example 11 was prepared in the same procedure as in Example 8 except that the coated silver particles Ag1 were used instead of the coated copper particles Cu1 and silver powder having an average particle diameter of 1 μm was used instead of the copper powder. Got The obtained bonding composition was excellent in dispersibility.

(Comparative Examples 1 to 6)
In Example 1, the bonding compositions of Comparative Examples 1 to 6 were obtained by the same procedure as in Example 1 except that the components and the blending amounts were changed as shown in Table 2 below. In Table 2, n-heptanal is manufactured by Tokyo Kasei Co., Ltd., and isophthalaldehyde is manufactured by Tokyo Kasei Co., Ltd. SC-0708A is a dispersant manufactured by NOF CORPORATION.

<Evaluation of stability when left unattended>
The bonding compositions of Examples 1 to 11 and Comparative Examples 1 to 6 were filled in a syringe (using a 3 cc clear syringe and a plunger for 3 cc (yellow): both manufactured by Musashi Engineering Co., Ltd.) and needles. (20-22G: manufactured by Musashi Engineering Co., Ltd.) with an air dispenser (ML5000XII: manufactured by Musashi Engineering Co., Ltd.) on the Au-plated surface of a 5 mm × 5 mm × 500 μm silicon substrate (Ti / Ni / Au plating). 2-4 mg was applied. Next, a silicon chip (Ti / Ni / Au plating) of 2 mm × 2 mm × 500 μm is placed on the bonding composition so that the Au plated surface is in contact with each other so that the distance between the silicon substrate and the silicon chip becomes 50 μm. Was crimped to.
Then, the silicon substrate and the silicon chip were heated at 100 ° C. for 60 minutes using an electric furnace (KDF900GL: manufactured by Denken Hydental Co., Ltd.). Then, the temperature was further raised to a predetermined sintering temperature at a rate of 10 ° C./min, and the mixture was heated at the sintering temperature for 60 minutes to obtain a bonded body.
The sintering temperature was 350 ° C. for the bonding compositions of Examples 1 to 8 and Comparative Examples 2 to 4, and 250 ° C. for the bonding compositions of Examples 11 and Comparative Examples 1 and 5 to 6. .. Further, the bonding compositions of Examples 9 and 10 were sintered at both sintering temperatures of 250 ° C. and 350 ° C. From the time when the heating of the coating film was started to the time when the inside of the electric furnace was cooled to 50 ° C., nitrogen gas was continuously supplied at a flow rate of 5 L / min.

The bonded bodies formed by using the bonding compositions of Examples 1 to 11 and Comparative Examples 1 to 6 were subjected to a die share test using a bond tester (Condor Sigma: manufactured by XYZTEC, the Netherlands), and the bonding strength was measured. did. The results are shown in Tables 3 and 4. In Tables 3 and 4, when the bonding strength is particularly high, it is indicated by "⊚", when the bonding strength is high, it is indicated by "◯", and when the bonding strength is low, it is indicated by "x".

[Summary of results]
As shown in Table 3, from the results of the bonding strength evaluation, it was found that the bonding compositions according to the present invention each exhibit sufficient bonding strength. This indicates that the bonding composition according to the present invention was excellent in bonding strength.

Further, when Examples 5 and 6 are compared, the bonded body using the bonding composition containing n-decanal (Example 5) is bonded using the bonding composition containing n-dodecanal (Example 6). It showed a particularly high joint strength compared to the body. This indicates that the bonding strength of the bonded body is improved by using n-decanal among the aliphatic aldehyde-based solvents.

Further, among Examples 1 to 11, the examples using liquid paraffin (Examples 1 to 5, 7, 9, 10) are compared with the examples not using liquid paraffin (Examples 8 and 11). It showed particularly high bonding strength. It is considered that this is because the liquid paraffin improved the dispersibility of the coated metal particles and the metal powder.

From the above results, one or more coating molecules selected from a plurality of aliphatic carboxylic acids (A1) and aliphatic aldehydes (A2) on the surface of the metal powder and the metal nuclei particles having a particle size smaller than that of the metal powder. The coated metal particles (A) coated with a density of 2.5 to 5.2 molecules / nm ² , the aliphatic carboxylic acid-based solvent (B1) having a boiling point of 160 ° C. or higher and 300 ° C. or lower, and the boiling point of 160 ° C. or higher and 300. It has been shown that a bonding composition containing one or more solvents (B) selected from an aliphatic aldehyde-based solvent (B2) at ° C. or lower forms a bonded body having excellent bonding strength.

Claims (3)

With metal powder,
2.5 to 5.2 molecules of one or more coating molecules selected from a plurality of aliphatic carboxylic acids (A1) and aliphatic aldehydes (A2) are formed on the surface of metal nuclei particles having a particle size smaller than that of the metal powder. The coated metal particles (A) coated with a density of / nm ² and
It contains one or more solvents (B) selected from the aliphatic aldehyde-based solvent (B2) having a boiling point of 160 ° C. or higher and 300 ° C. or lower.
Combining composition. With metal powder,
2.5 to 5.2 molecules of one or more coating molecules selected from a plurality of aliphatic carboxylic acids (A1) and aliphatic aldehydes (A2) are formed on the surface of metal nuclei particles having a particle size smaller than that of the metal powder. The coated metal particles (A) coated with a density of / nm ² and
One or more solvents (B) selected from an aliphatic carboxylic acid solvent (B1) having a boiling point of 160 ° C. or higher and 300 ° C. or lower and an aliphatic aldehyde solvent (B2) having a boiling point of 160 ° C. or higher and 300 ° C. or lower.
Contains liquid paraffin ,
Combining composition. The aliphatic aldehyde-based solvent (B2) contains decanal.
The bonding composition according to claim 1 or 2 .