JP2022099238A - Metal particle-containing composition, paste for joining, joined body, and production method of joined body - Google Patents

Abstract

To provide a metal particle-containing composition which produces high joining strength at a joined position and of which the lowering of the joining strength due to cooling and heating cycles is suppressed, to provide a paste for joining which, in addition to the above mentioned characteristics, has excellent printability on a part to be joined even when the metal particles are contained with high concentration, and further to provide a joined body which is not degraded by the cooling and heating cycles with a long-term of 1,000 cycles or more.SOLUTION: A metal particle-containing composition is characterized as comprising: metal particles (A) with an average particle diameter of 1-1,000 nm; a multivalent fatty acid (B); and a polyamine (C). In addition, a paste for joining comprises the metal particle-containing composition and a dispersion medium (F). Furthermore, a joined body is formed of a first part to be joined and a second part to be joined which are joined to each other via a joining layer, in which the joining layer is a layer formed of the paste for joining.SELECTED DRAWING: None

Description

The present invention relates to a metal particle-containing composition, a paste for joining, a bonded body, and a method for producing the bonded body.

Conventionally, solder has been used as a bonding material for adhering metal members to each other, a metal member to a semiconductor element, a metal member to a light emitting diode (LED) element, or the like. In recent years, in the technical field of next-generation power electronics, devices such as SiC that can operate at high temperatures are required. As a joining material for manufacturing such a device, an alternative material for solder is required from the viewpoint of high temperature drive reliability. For example, metal particles having sinterability as shown in Patent Documents 1 to 4. A joining material such as a joining paste using the above has been proposed.

Patent Document 1 describes metal submicron particles having an average primary particle size of 0.5 to 3.0 μm and metal nanoparticles having an average primary particle size of 1 to 200 nm and coated with an organic compound having 6 to 8 carbon atoms. A bonding material containing particles is disclosed. However, there is a problem that the bonding strength at the bonded portion is poor and the bonding strength decreases with the cooling / heating cycle.

Patent Document 2 discloses a bonding material containing silver nanoparticles having an average primary particle diameter of 1 to 200 nm and being coated with an organic substance having 8 or less carbon atoms and a flux component having at least two carboxyl groups. Has been done. Further, Patent Document 3 discloses a bonding material containing silver fine particles having an average primary particle diameter of 130 nm or less and a crosslinked particle-to-particle distance-preserving agent that maintains the distance between the silver fine particles.

Patent Document 4 describes metal particles containing metal nanoparticles having an average particle diameter of 2 to 200 nm, specific polyamides having a phenolic hydroxyl group in the side chain and having a hydrocarbon group having 20 to 60 carbon atoms, and the phenol. A bonding material containing a trifunctional or higher functional compound capable of reacting with a phenolic hydroxyl group is disclosed.

However, in the joining materials described in Patent Documents 1 to 4, since defects such as voids (voids) are formed in the joining portion, the strength of the joined portion is poor, and the joining strength increases with the thermal cycle. There was the problem of lowering. Further, when a bonding paste containing a high concentration of silver nanoparticles is prepared in order to realize a dense and strong bonding, there is a drawback that the fluidity is significantly poor. As a result, in the process of printing the bonding paste on the bonded portion, there is a problem that the printed portion is blurred or a portion that cannot be coated is generated (a non-coated portion is formed).

Japanese Unexamined Patent Publication No. 2011-80147 Japanese Unexamined Patent Publication No. 2011-240406 JP-A-2018-109232 Japanese Unexamined Patent Publication No. 2017-137375

Therefore, an object to be solved by the present invention is to provide a metal particle-containing composition in which the bonding strength at the bonded portion is high and the decrease in bonding strength due to the thermal cycle is suppressed. Further, in addition to the above-mentioned characteristics, it is an object of the present invention to provide a bonding paste having excellent printability on a bonded portion even if it contains metal particles at a high concentration. Further, it is to provide a bonded body which is not deteriorated by a long-term cooling / heating cycle of 1000 cycles or more.

The present inventors have reached the present invention as a result of repeated diligent studies to solve the above problems.
That is, the present invention relates to a metal particle-containing composition characterized by containing metal particles (A) having an average particle diameter of 1 nm to 1000 nm, a polyvalent fatty acid (B), and a polyamine (C).

The present invention also relates to the above-mentioned metal particle-containing composition in which the polyvalent fatty acid (B) has 20 to 80 carbon atoms and the polyamine (C) has 20 to 80 carbon atoms.

The present invention also relates to the above metal particle-containing composition in which the polyunsaturated fatty acid (B) contains divalent and / or trivalent fatty acids.

The present invention also relates to the above metal particle-containing composition in which the polyamine (C) contains a diamine and / or a triamine.

The present invention also relates to the above metal particle-containing composition in which the polyunsaturated fatty acid (B) and / or the polyamine (C) has a branched and / or cyclic structure.

Further, in the present invention, when the valence of the polyvalent fatty acid (B) is m and the valence of the polyamine (C) is n, does the polyvalent fatty acid (B) have an m-valent hydrocarbon group (D)? , The metal particle-containing composition in which the polyamine (C) has an n-valent hydrocarbon group (E).

The present invention also relates to the above-mentioned metal particle-containing composition in which the carbon number of the m-valent hydrocarbon group (D) and / or the carbon number of the n-valent hydrocarbon group (E) is 30 to 60.

Further, the present invention contains 0.05 parts by mass to 1 part by mass of the polyvalent fatty acid (B) and / or 0.05 parts by mass to 1 part by mass of the polyamine (C) with respect to 100 parts by mass of the metal particles (A). The present invention relates to the above-mentioned metal particle-containing composition.

Further, in the present invention, with respect to 100 parts by mass of the metal particles (A), 0.1 parts by mass to 0.5 parts by mass of the polyvalent fatty acid (B) and / or 0.1 parts by mass to 0. The present invention relates to the above-mentioned metal particle-containing composition containing 5 parts by mass.

The present invention also relates to the metal particle-containing composition having an average particle diameter of the metal particles (A) of 180 nm to 400 nm.

The present invention also relates to the above-mentioned metal particle-containing composition in which the average particle diameter of the metal particles (A) is 200 nm to 300 nm.

The present invention also relates to a bonding paste containing the metal particle-containing composition and the dispersion medium (F).

Further, in the present invention, the ratio of the mass of the metal particles (A) to the sum of the masses of the metal particles (A), the polyvalent fatty acid (B), the polyamine (C) and the dispersion medium (F) is 80% by mass. The present invention relates to the above-mentioned bonding paste having an amount of about 95% by mass.

Further, the present invention is a bonded body in which a first bonded portion and a second bonded portion are bonded via a bonding layer, and the bonding layer is a layer formed by the above-mentioned bonding paste. Regarding the joint.

Further, the present invention is a method for manufacturing a bonded body in which a first bonded portion and a second bonded portion are bonded via a bonding layer, and the metal particles having an average particle diameter of 1 nm to 1000 nm ( A bonding paste containing A), a polyvalent fatty acid (B), a polyamine (C), and a dispersion medium (F) is applied to the first bonded portion, and the second bonded portion is placed. The present invention relates to a method for producing a bonded body, which comprises a step of performing sintering.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a metal particle-containing composition having high bonding strength at a bonded portion and the bonding strength does not decrease with a long-term cold heat cycle, and a bonding paste having excellent printability in addition to these effects. It became so. In addition, it has become possible to provide a bonded body that does not deteriorate due to the thermal cycle.

The metal particle-containing composition of the present invention contains metal particles (A) having an average particle diameter of 1 nm to 1000 nm, a polyvalent fatty acid (B), and a polyamine (C). Further, the bonding paste of the present invention contains a dispersion medium (F) in addition to the metal particle-containing composition. The metal particle-containing composition may be formed from the bonding paste by volatilizing part or all of the dispersion medium (F) during the bonding process.
In the present specification, "metal particles (A) having an average particle diameter of 1 nm to 1000 nm" may be abbreviated as "metal particles (A)".

The metal particles (A) are in the range of a specific average particle size, and when heated or sintered, the particles melt or bind to each other (hereinafter, also referred to as sintering) and change into bulk metal. As a result, the parts to be joined can be joined to each other. Hereinafter, the portion formed by sintering the metal particle-containing composition existing between the bonded portions is referred to as a bonding layer.

Further, since the bonding paste of the present invention contains a polyvalent fatty acid (B) and a polyamine (C), a bonding layer having few defects such as voids (voids) can be obtained at the time of sintering. It is presumed that the bond strength is high and the decrease in bond strength is suppressed even after a long-term cold heat cycle.

The temperature at which the metal particle-containing composition or the bonding paste is sintered is not particularly limited, but in general, it is often sintered at 200 ° C to 350 ° C. By performing sintering, dehydration condensation of the polyvalent fatty acid (B) and the polyamine (C) occurs, and in the latter stage of the sintering time, the polyvalent fatty acid (B) and the polyamine (C) are dehydrated in the bonding layer. A fused polyamide is formed. Therefore, even if organic substances remain in the produced joint layer, it is considered that volatilization is suppressed by polymerization and heat resistance is improved. As a result, it is considered that the decrease in bonding strength due to the long-term cold cycle test can be suppressed.

<Metal particles (A)>
Examples of the metal in the metal particles (A) include gold, silver, copper, nickel, chromium, palladium, rhodium, ruthenium, indium, silicon, aluminum, tungsten, molybdenum, platinum and alloys thereof. Further, examples thereof include a nucleus and fine particles coated with a substance different from the nucleus substance, specifically, silver-coated copper powder having copper as a nucleus and its surface coated with silver. Further, powders of metal oxides such as silver oxide, indium oxide, tin oxide, zinc oxide, ruthenium oxide, ITO (tin-doped indium oxide), AZO (aluminum-doped zinc oxide), and GZO (gallium-doped zinc oxide), and these. The powder surface-coated with the metal oxide of the above can also be mentioned. The type of metal used may be one type, or two or more types may be used in combination.

The metal particles (A) are preferably selected from copper or silver in that a bonded body having particularly excellent strength can be obtained. Furthermore, the metal particles (A) are more likely to be silver in that they can be used in a wide range of firing temperatures and can be used in various firing environments such as atmospheric pressure, nitrogen atmosphere, vacuum, or reduction atmosphere. preferable.

In the present invention, it is important to use metal particles (A) having a specific average particle size. The "average particle size" as used herein means a 50% integrated particle size distributed particle size (d50) based on the volume obtained by the measuring method described in the examples. The d50 of the metal particles (A) is 1 to 1000 nm, preferably 180 to 400 nm, and more preferably 200 to 300 nm.

The surface of the metal particles (A) is preferably coated with the organic component (a). When coated with the organic component (a), it can be expected that the storage stability of the metal particle-containing composition and the bonding paste will be increased. Examples of the organic component (a) include fatty acids, aliphatic amines and aliphatic alcohols, but saturated or unsaturated fatty acids are preferable, and saturated or unsaturated fatty acids having 3 to 18 carbon atoms. More preferably, it is a saturated or unsaturated fatty acid having 6 to 18 carbon atoms. The organic component (a) may contain one kind or two or more kinds.

The metal particles (A) may be used alone or in combination of two or more. Further, if necessary, metal particles other than the metal particles (A) may be used in combination. In that case, it is preferable to use a combination of metal particles having a particle size exceeding 1000 nm on average.

<Polyunsaturated fatty acid (B)>
Next, the polyunsaturated fatty acid (B) will be described. The polyunsaturated fatty acid (B) refers to a compound having a plurality of carboxy groups in the molecule and having a hydrocarbon as a basic skeleton. The polyunsaturated fatty acid (B) preferably has 20 to 80 carbon atoms. Regarding the carbon number of the polyunsaturated fatty acid (B), the carboxycarbon in the molecule is also regarded as the carbon number of the polyunsaturated fatty acid (B).

The polyunsaturated fatty acid (B) is considered to have an effect of maintaining the metal particle-containing composition in a fluid liquid state at the time of sintering, and is presumed to increase the wettability at the bonding interface with the bonded portion. Therefore, even if voids are generated in the bonding layer, it is considered possible to flow into the defective portion and obtain a bonding layer having few defects and high bonding strength.

The properties of the polyunsaturated fatty acid (B) are not particularly limited, but are preferably liquid in a normal temperature range of 200 ° C. to 350 ° C. in which the metal particle-containing composition of the present invention is fired. The polyunsaturated fatty acid (B) may be solid or liquid at room temperature (25 ° C.), but is liquid at room temperature in that it can be uniformly dispersed in the metal particle-containing composition and can act effectively. Is more preferable.

The valence of the polyunsaturated fatty acid (B), that is, the number of carboxy groups is preferably 2 or 3.

The polyunsaturated fatty acid (B) may have a linear structure or a branched and / or cyclic structure, but preferably has a branched and / or cyclic structure. When it has a branched and / or cyclic structure, it is preferable in that it has low crystallinity and tends to become a liquid having good fluidity. Further, the branched and / or cyclic structure is preferable in that increasing the flexibility of the polyamide formed from the polyunsaturated fatty acid (B) and the polyamine (C) leads to an improvement in the bonding strength and suppression of a decrease in the bonding strength.

When the valence of the polyunsaturated fatty acid (B) is m, the polyunsaturated fatty acid (B) preferably has an m-valent hydrocarbon group (D). In the polyunsaturated fatty acid (B), the skeleton excluding the carboxy group is more preferably composed of only m-valent hydrocarbons.

When the number of carbon atoms of the m-valent hydrocarbon group (D) is 30 to 60, it is more preferable in that the bonding strength at the initial stage and after the cycle test is particularly high.

Specific examples of the polyvalent fatty acid (B) include malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedi as linear structures. Acid, Hexadecanedioic acid, Octadecandioic acid, Eikosandioic acid, Heneicosandioic acid, Docosandioic acid, Tetracosandioic acid, Triacontanedioic acid, Dotoriacontanedioic acid, Tetracontandioic acid, Pentacontanedioic acid, Hexacontandi Examples thereof include, but are not limited to, acids.

Further, examples of the branched and / or cyclic structure include, but are not limited to, methylmalonic acid, dimer acid, trimer acid, tetramer acid and the like.

Among these specific examples, the polyunsaturated fatty acid (B) more preferably contains dimer acid and / or trimer acid.

Dimeric acid, trimer acid and tetramer acid can be produced by a quantification reaction of unsaturated fatty acids. For example, it can be produced by a Diels-Alder reaction between oleic acid (18 carbon atoms) and linoleic acid (18 carbon atoms) or a radical reaction. The dimer acid, trimer acid and tetramer acid preferably have 36 or 44, 54 and 72 carbon atoms, respectively. Further, by appropriately changing the carbon number of the unsaturated fatty acid as a raw material, it is possible to produce a polyunsaturated fatty acid (B) having a carbon number other than the above.
In this specification, the dimer, trimer and tetramer of unsaturated fatty acids having 12 or more carbon atoms are referred to as dimer acid, trimer acid and tetramer acid, respectively.

The polyunsaturated fatty acid (B) may be a mixture of compounds having different degrees of massification due to the production method, but may be used as a mixture of different multimers, or a specific single compound may be used. ..

<Polyamine (C)>
Next, the polyamine (C) will be described. Polyamine (C) means a compound having a plurality of amino groups (-NH ₂ groups) in the molecule. The polyamine (C) preferably has 20 to 80 carbon atoms.

In the polyamine (C), the skeleton (partial structure) excluding the amino group is an organic residue, but the hydrocarbon group or the hydrocarbon group may be a group bonded with a linking group which may contain a hetero atom. preferable. Examples of the linking group containing such a hetero atom include an —O— group (ether group), an —C (= O) − group (carbonyl group), and an —C (= O) —O— group (ester group, Examples thereof include an oxycarbonyl group) and a -C (= O) -NH- group (also referred to as an amide group and an iminocarbonyl group). Further, an arylene group such as a phenylene group and a naphthylene group is also included in the linking group.

Similar to the polyunsaturated fatty acid (B), the polyamine (C) is considered to have an effect of maintaining the metal particle-containing composition in a fluid liquid state at the time of sintering, and has a wettability at the bonding interface with the bonded portion. It is presumed to increase. Therefore, even if voids are generated in the bonding layer, it is considered that it is possible to obtain a bonding layer having few defects and high bonding strength by flowing into the metal particle defect portion.

The properties of the polyamine (C) are not particularly limited, but are preferably liquid in a normal temperature range of 200 ° C. to 350 ° C. in which the metal particle-containing composition of the present invention is fired. The polyamine (C) may be solid or liquid at room temperature (25 ° C.), but is more preferably liquid at room temperature in that it can be uniformly dispersed in the metal particle-containing composition and can act effectively. ..

The number of amino groups (-NH ₂ ) in the polyamine (C) is preferably 2 or 3. The polyamine (C) preferably contains a diamine and / or a triamine.

The polyamine (C) may have a linear structure, a branched and / or a cyclic structure, but preferably has a branched and / or a cyclic structure. When it has a branched and / or cyclic structure, it is preferable in that it has low crystallinity and tends to become a liquid having good fluidity.

When the number of amino groups (-NH ₂ ) of the polyamine (C) is n, the polyamine (C) preferably has an n-valent hydrocarbon group (E). In the polyamine (C), it is more preferable that the skeleton excluding the amino group (-NH ₂ ) consists of only n-valent hydrocarbons. When the n-valent hydrocarbon group (E) has 30 to 60 carbon atoms, it is more preferable in that the bonding strength at the initial stage and after the cycle test is particularly high.

Among the polyamines (C), examples of the polyamine having a linear structure include ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,6-hexanediamine, 1,7-heptanediamine, and 1, Examples of polyamines having a branched and / or cyclic structure include 9-nonanediamine and 1,12-diaminododecane, and examples thereof include metaxylenediamine, isophoronediamine, norbornandiamine, 1,2-cyclohexanediamine, and 1,3-cyclohexane. Examples thereof include diamine, 1,4-cyclohexanediamine, 4,4'-diaminodicyclohexylmethane, piperazine and the like. In addition, diamine diamine, trimer triamine, and tetramer tetramine are also contained in the polyamine (C). Among these specific examples, the polyamine (C) more preferably contains a diamine diamine and / or a trimer triamine.

Dimer diamine has a structure in which a carboxy group of dimer acid, trimer triamine has a carboxy group of trimer acid, and tetramer tetramine has a structure in which a carboxy group of tetramer acid is functionally converted into an amino group. The diamine diamine, trimertriamine and tetramertetramine preferably have 36, 54 and 72 carbon atoms, respectively.

The combination of the polyunsaturated fatty acid (B) and the polyamine (C) is not limited, but the polyunsaturated fatty acid (B) contains a dimer acid and / or a trimer acid, and the polyamine (C) contains a diamine diamine and / or a trimer triamine. A combination is more preferable.

The metal particle-containing composition of the present invention preferably contains 0.05 parts by mass to 1 part by mass of the polyvalent fatty acid (B) with respect to 100 parts by mass of the metal particles (A), preferably 0.1. It is more preferably parts by mass to 0.5 parts by mass. Further, the blending amount of the polyamine (C) is preferably 0.05 part by mass to 1 part by mass, and further 0.1 part by mass to 0.5 part by mass with respect to 100 parts by mass of the metal particles (A). It is more preferable that it is a part. When the blending amount is within this range, the fluidity at the time of sintering can be expected to increase, which is preferable in that a bonded body having excellent initial and long-term cycle resistance can be easily obtained.

The mixing ratio of the polyvalent fatty acid (B) and the polyamine (C) is not limited, but the mass ratio of the polyvalent fatty acid (B) / polyamine (C) is 0.1 / 0.9 in that polyamide is easily formed. It is preferably ~ 0.9 / 0.1, and more preferably 0.3 / 0.7 to 0.7 / 0.3.

<Dispersion medium (F)>
The bonding paste of the present invention contains a dispersion medium (F). The dispersion medium (F) has a function of dispersing the metal particles (A), the polyunsaturated fatty acid (B), and the polyamine (C).
The dispersion medium (F) may be capable of dispersing metal particles (A), polyvalent fatty acid (B), and polyamine (C), and specific examples thereof include tarpineol, dihydroterpineol, dihydroterpinyl acetate, and tersolve MTPH ( Nippon Terupen Co., Ltd.), Texanol (2,2,4-trimethylpentane-1,3-diol monoisobutyrate), carbitol, carbitol acetate, butyl carbitol, isophorone, γ-butyl lactone, dipropylene glycol Monomethyl Ether, Dipropylene Glycol Methyl-n-propyl Ether, 3-methoxy-3-Methylbutyl Acetate, Ethylene Glycol, Hexic Acid, Propylene Glycol Diacetate, Dipropylene Glycol Methyl Ether Acetate, 1,3-butylene Glycol, Hydrocarbons Examples thereof include isoparaffin solvents contained in the solvent, but the solvent is not limited thereto.

Among these dispersion media (F), tarpineol, dihydroterpineol, tersolve MTPH, texanol, carbitol, carbitol acetate, butyl carbitol, isophorone, γ-butyl lactone, dipropylene glycol monomethyl ether, and isoparaffin solvent are more suitable. It is preferably used. These dispersion media (F) can be used alone or in combination of two or more.

The bonding paste of the present invention has good adhesion to the bonded portion even after a part or all of the dispersion medium (F) is volatilized due to the coexistence of the polyunsaturated fatty acid (B) and the polyamine (C). It is possible to form a flexible bonding interface.

By using the metal particles (A), the polyvalent fatty acid (B), and the polyamine (C) in combination, the bonding paste of the present invention contains the metal particles (A) in a high concentration, that is, a dispersion medium. Even when the content ratio of (F) is small, it has excellent fluidity, so that it is excellent in printability on the bonded portion. In addition, the bonding paste of the present invention does not have a possibility that the compatibility of the components is lowered to make it non-uniform or the fluidity is impaired as compared with the case where the polyamide resin is added. As a result, it is possible to obtain a strong joint with fewer defects.

In the bonding paste, the ratio of the mass of the metal particles (A) to the sum of the masses of the metal particles (A), the polyvalent fatty acid (B), the polyamine (C) and the dispersion medium (F) is 80% by mass or more. It is preferably 95% by mass, more preferably 85% by mass to 94% by mass. By including it in the above range, good printability as a bonding paste can be ensured. Further, by including the content in the above range, the residue of the dispersion medium (F) in the bonded body can be suppressed, and voids derived from the dispersion medium (F) are unlikely to occur, so that good bonding strength can be exhibited.

<Other ingredients>
The bonding paste of the present invention may further contain other components such as additives. Examples of the other components include a sintering accelerator, a binder resin, a dispersant such as a small molecule dispersant and a resin type dispersant.
As the dispersant that may be contained in the bonding paste of the present invention, a low molecular weight dispersant having a molecular weight of 150 to 600 is preferable, and an unsaturated fatty acid having 18 to 22 carbon atoms or an unsaturated fatty acid having 18 to 22 carbon atoms is preferable. More preferably, it is a fatty acid amide. Unsaturated fatty acids are monovalent fatty acids having unsaturated bonds, and specific examples thereof include oleic acid, elaidic acid, linolenic acid, linolenic acid, ricinoleic acid, and erucic acid. The unsaturated fatty acid amide is a monovalent fatty acid amide having an unsaturated bond, and specific examples thereof include oleamide (oleic acid amide) and erucic acid amide. By containing these dispersants, the metal particles (A) in the bonding paste can be loosened more uniformly, and a strong bonded body with less bias of voids can be obtained, which is preferable.
Although the amount of the low-molecular-weight dispersant is not limited, it is preferable with respect to 100 parts by mass of the metal particles (A) in terms of achieving both good dispersion of the metal particles (A) and densification of the bonding layer. It is 0.1 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, and even more preferably 0.2 to 2 parts by mass.

Examples of the apparatus for preparing the bonding paste from the metal particles (A), the compound (B) and the dispersion medium (C) include a disper, three rolls, a bead mill, an ultrasonic disperser, a self-revolving stirrer and the like. ..

<Joint body>
With the bonding paste of the present invention, the first bonded portion and the second bonded portion can be bonded to obtain a bonded body. Specifically, the bonded body of the present invention is a bonded body in which a first bonded portion and a second bonded portion are bonded via a bonding layer, and the bonded body is, for example, an average particle diameter. A bonding paste containing metal particles (A) having a diameter of 1 nm to 1000 nm, a polyvalent fatty acid (B), a polyamine (C), and a dispersion medium (F) is applied to the first bonded portion. It can be manufactured by a manufacturing method including a step of placing a second bonded portion and performing sintering.
The method of applying the bonding paste to the bonded portion is not particularly limited as long as it can be uniformly applied on the member. Examples thereof include various printing methods such as screen printing, flexo printing, offset printing, gravure printing, metal mask printing, and gravure offset printing, and ejection methods using a dispenser. The bonding paste of the present invention has a high concentration of metal. Even if it contains particles, it has excellent fluidity, so it is particularly preferable to use it in combination with metal mask printing.

When the second bonded portion is placed on the first bonded portion to which the bonding paste of the present invention is applied, the second bonded portion can be placed while applying pressure. The pressure is appropriately set depending on the viscosity of the bonding paste and the dry state of the paste, but is preferably 0.1 to 40 MPa, more preferably 0.3 to 30 MPa.

The sintering conditions for joining the laminate in which the second bonded portion is placed on the first bonded portion are appropriately changed, and are, for example, under atmospheric pressure, nitrogen atmosphere, vacuum, or reduction. Conditions such as 200 to 350 ° C. can be mentioned in the atmosphere. Examples of the firing device include a hot air oven, an infrared oven, a reflow oven, a microwave oven, a hot plate, a light firing device, and the like. These devices may be used individually or in combination as appropriate. Further, pressure may be applied while sintering. The pressure is appropriately set depending on the viscosity of the bonding paste and the dry state of the paste, but is preferably 0.1 to 40 MPa, more preferably 0.3 to 30 MPa.

Prior to the firing step, a pre-drying step may be appropriately added for the purpose of removing organic components in the bonded coating film. For example, a condition in the range of 60 to 220 ° C. can be mentioned using a device similar to the firing device.

As a preferable method for joining two bonded portions, the bonding paste of the present invention is applied to the first bonded portion, then the second bonded portion is placed, and the temperature is up to about 300 ° C. at 2 ° C. A method of raising the temperature at a heating rate of about / minute and performing sintering can be mentioned. After the temperature rise is completed, it is preferable to maintain the temperature at a temperature higher than the temperature at the end of the temperature rise for about 10 minutes to 2 hours.

The type of the bonded portion is not particularly limited, and examples thereof include metal materials, semiconductor materials, plastic materials, and ceramic materials. Moreover, the electronic element can be mentioned.

Examples of the metal include copper, gold, aluminum and the like.
Examples of the semiconductor material include silicon (silicon), germanium, gallium arsenide, gallium phosphide, cadmium sulfide, silicon nitride, graphite, yttrium oxide, magnesium oxide, silicon carbide, gallium nitride, gallium oxide and the like.
Examples of the plastic material include polyimide, polyethylene, polypropylene, polyethylene terephthalate, polycarbonate, polyethylene naphthalate and the like.
Examples of the ceramic material include glass, silicon and the like.
Further, examples of the electronic element include a semiconductor element, an LED element, a power device element, and the like.

The first joined portion and the second joined portion may be not only the same type but also different types of members. The surface of the bonded portion may be subjected to corona treatment, plating treatment, or the like in order to increase the bonding strength of the bonded portion.

The film thickness of the bonding layer formed when the bonded portion is bonded with the metal particle-containing composition or the bonding paste of the present invention is not limited, but is preferably 3 μm to 500 μm, more preferably 10 μm to 200 μm, and 20 μm to 20 μm. 100 μm is more preferable.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the technical scope of the present invention is not limited thereto. In the example, "part" means "part by mass" and "%" means "% by mass" unless otherwise specified, and the numerical values in the table represent "part" unless otherwise specified. ..

<Manufacturing of metal particles>
(Manufacturing Example 1) Metal Particle A1
Under a nitrogen atmosphere, 200 parts of toluene and 22.3 parts of silver hexanoate were mixed with stirring at 25 ° C. to prepare a 0.5 M solution, and then 1.6 parts of diethylaminoethanol and 0.28 parts of oleic acid were used as dispersants. Was added and dissolved. Then, when 73.1 parts of an aqueous solution of succinic acid dihydrazide (hereinafter referred to as SUDH) having a concentration of 20% was added dropwise as a reducing agent, the liquid color changed from pale yellow to dark brown. The temperature was raised to 40 ° C. to further promote the reaction, and the reaction was allowed to proceed. After standing and separating, excess reducing agent and impurities are removed by taking out the aqueous phase, distilled water is added to the toluene layer several times, washing and separation are repeated, then toluene is added and the supernatant is separated. The step of removing the above was repeated twice. The precipitate was dried to give metal particles A1 in which the silver particles were coated with caproic acid and oleic acid. When the particle size of the metal particles A1 was determined by the method described later, d50 was 210 nm.

(Manufacturing Example 2) Metal Particle A2
Metal particles A2 were obtained in the same manner as in Production Example 1 except that the amount of diethylaminoethanol was 1.8 parts and the amount of oleic acid was 0.31 parts. d50 was 185 nm.
(Manufacturing Example 3) Metal Particle A3
Metal particles A3 were obtained in the same manner as in Production Example 1 except that the amount of diethylaminoethanol was 1.2 parts and the amount of oleic acid was 0.18 parts. d50 was 290 nm.
(Manufacturing Example 4) Metal Particle A4
Metal particles A4 were obtained in the same manner as in Production Example 1 except that the amount of diethylaminoethanol was 1.0 part and the amount of oleic acid was 0.14 part. d50 was 390 nm.
(Manufacturing Example 5) Metal Particle A5
Metal particles A5 were obtained in the same manner as in Production Example 1 except that the amount of diethylaminoethanol was 2.1 parts and the amount of oleic acid was 0.71 parts. d50 was 85 nm.
(Manufacturing Example 6) Metal Particle A6
Metal particles A6 were obtained in the same manner as in Production Example 1 except that the amount of diethylaminoethanol was 0.6 part and the amount of oleic acid was 0.070 part. d50 was 1100 nm.
Among the metal particles produced by the above method, the metal particles A1 to A5 correspond to the metal particles (A), and the metal particles A6 correspond to the metal particles other than the metal particles (A).

[Measurement of particle size]
Isopropyl alcohol was added to each metal particle (A) and dispersed by an ultrasonic disperser to obtain a dispersion liquid of 0.5% by mass. Using Nanotrack UPA-EX150 (manufactured by Nikkiso Co., Ltd.), the particle size of the metal particles (A) in the dispersion was measured, and the average particle size (d50) was determined.

[Fatty acids, amines and other ingredients]
Materials such as fatty acids and amines used in Examples and Comparative Examples are as follows. The number of carbon atoms, material name, and properties at 25 ° C are shown in parentheses. Of the following, prepol and preamine used were reagents manufactured by Croda Japan Co., Ltd., oleic acid amide was manufactured by Tokyo Chemical Industry Co., Ltd., and other materials were reagents manufactured by Sigma-Aldrich. The fatty acids B1 to B3, B5 and B6 correspond to the polyunsaturated fatty acid (B), and the amines C1 to C3 correspond to the polyamine (C). Fatty acid B4 and fatty acid amide G1 correspond to dispersants that may be added to the present invention.

Fatty acid B1: Pripol 1009 (hydrogenated dimer acid having 36 carbon atoms, consisting of two carboxy groups and a divalent hydrocarbon group having a branched and cyclic structure. Liquid polyvalent fatty acid).
Fatty acid B2: Pripol 1040 (trimeric acid having 54 carbon atoms, consisting of three carboxy groups and a trivalent hydrocarbon group having a branched and cyclic structure. A liquid polyvalent fatty acid).
Fatty acid B3: Linear dibasic acid (consisting of 22 carbon atoms, docosanedioic acid, two carboxy groups, and a divalent hydrocarbon having a linear structure. Solid polyvalent fatty acid)
Fatty acid B4: Oleic acid (monovalent linear fatty acid with 18 carbon atoms. Liquid monovalent unsaturated fatty acid)
Fatty acid B5: Malonic acid (straight-chain dibasic acid with 3 carbon atoms. Solid polyunsaturated fatty acid)
Fatty acid B6: Pripol 1004 (hydrogenated dimer acid having 44 carbon atoms, consisting of two carboxy groups and a divalent hydrocarbon group having a branched and cyclic structure. Liquid polyvalent fatty acid).
Amine C1: Preamine 1071 [Dimerdiamine with 36 carbon atoms (a liquid polyamine consisting of two amino groups and a divalent hydrocarbon group having a branched and cyclic structure) and trimertriamine with 54 carbon atoms (three amino groups). A mixture of a liquid polyamine) consisting of a trivalent hydrocarbon group having a branched and cyclic structure)]
Amine C2: Priamine 1075 (diamine diamine having 36 carbon atoms, consisting of two amino groups and a divalent hydrocarbon group having a branched and cyclic structure. A liquid polyamine).
Amine C3: 1,12-diaminododecane (a solid polyamine consisting of an amino group having 12 carbon atoms and two amino groups and a divalent hydrocarbon group having a linear structure).
Amine C4: Oleylamine (monoamine linear monoamine with 18 carbon atoms, liquid)
Fatty acid amide G1: Oleic acid amide (individual monounsaturated fatty acid amide)

(Production Example 7) Polyamide containing a phenolic hydroxyl group (polyamide P1)
Polyamide P1 was synthesized as follows with reference to JP-A-2017-137375. 202.9 g of prepol 1009 (0.35 mol in terms of dibasic acid) and 25.7 g of 5-hydroxyisophthalic acid in a 4-necked flask equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, an introduction tube, and a thermometer. (0.14 mol), 35.1 g (0.21 mol) of terephthalic acid, 313.9 g (0.59 mol in terms of diamine) of preamine 1074 (manufactured by Croder Japan Co., Ltd.) as a polyamine compound having 36 carbon atoms, and 100 g of water. , Stirred until the temperature of the heat generation became constant. When the temperature became stable, the temperature was raised to 110 ° C, and after confirming the outflow of water, the temperature was raised to 120 ° C 30 minutes later, and then the dehydration reaction was continued while raising the temperature by 10 ° C every 30 minutes. .. When the temperature reached 230 ° C., the reaction was continued at the same temperature for 3 hours, held under a vacuum of about 2 kPa for 1 hour, and then allowed to cool to obtain a polyamide P1 containing a phenolic hydroxyl group having a weight average molecular weight of 9,800. Obtained.

(Production Example 8) Polyamide containing a phenolic hydroxyl group (polyamide P2)
In Production Example 7, 202.9 g of prepol 1009 (0.35 mol in terms of dibasic acid) was replaced with 243.1 g of prepole 1004 (0.35 mol in terms of dibasic acid), and the weight average was the same. Polyamide P2 containing a phenolic hydroxyl group having a molecular weight of 11,700 was obtained.

[Dispersion medium (F)]
The following materials were used as the dispersion medium (F). The manufacturer name and supplementary information obtained are listed in parentheses.
Dispersion medium F1: Dihydroterpineol (manufactured by Nippon Terpene Chemical Co., Ltd.)
Dispersion medium F2: Isobornylcyclohexanol (manufactured by Nippon Terpene Chemical Co., Ltd.)
Dispersion medium F3: Isopar L (manufactured by Ando Parachemy Co., Ltd.)
Dispersion medium F4: Texanol (manufactured by Tokyo Chemical Industry Co., Ltd., reagent)

<Manufacturing of bonding paste>
[Example 1]
Metal particles A1 (92 parts), dihydroterpineol (8 parts), fatty acid B1 (0.15 parts) and amine C2 (0.15 parts) were mixed using a self-revolving stirrer to prepare a bonding paste. .. Then, a bonded body was prepared and evaluated by the method described later. The results are shown in Table 1.

[Examples 2 to 39], [Comparative Examples 1 to 8]
After obtaining a bonding paste and a bonded body in the same manner as in Example 1 except that the type and blending amount of the materials were changed according to the composition shown in Table 1, evaluation was performed. The results are shown in Table 1.

<Evaluation of bonding paste>
[Preparation of bonded body]
After printing each of the bonding pastes on the plated surface of the bonded portion 1 below once under the printing conditions below, the plated surface of the bonded portion 2 (chip) described below is directed toward the bonded paste surface. And heated under the following sintering conditions to obtain a bonded body.
<Jointed part 1>
-Gold-plated copper base material: 20 x 20 x 3 mm
<Jointed part 2>
-Gold-plated SiC chip: 5 x 5 x 0.3 mm
<Printing conditions (metal mask printing)>
-Metal mask: Opening 4 mm square, plate thickness 50 μm (manufactured by Celia Corporation)
-Metal squeegee: 40 mm x 250 mm, thickness 1 mm (manufactured by Celia Corporation) <Sintering conditions>
The bonded body before sintering was placed in a hot air oven, the temperature was raised from 25 ° C. to 300 ° C. under the condition of 2 ° C./min, and after reaching 300 ° C., the temperature was maintained at 300 ° C. for 2 hours.
[Evaluation criteria (printability)]
◯: Printing was possible on the bonded portion 1.
X: Printing could not be performed on the bonded portion 1.

[Joint strength (initial, after thermal cycle test]
The joint strength (die shear strength) of the obtained joint was measured with the following measuring device and test conditions. In addition, * (US mark) in Table 1 indicates that this evaluation was not carried out because it could not be printed.
Measuring device: Universal bond tester (4000 series manufactured by Daiji Japan Co., Ltd.)
<Test conditions>
・ Measurement height: 100 μm
・ Measurement speed: 500 μm / s

Specifically, the bonded body is fixed at the site of the bonded portion 1, and the position at a height of 100 μm toward the bonded portion 2 from the interface between the bonded portion 1 and the bonded layer is at a speed of 500 μm / s. The joint strength was obtained by pressing with. The joint strength (initial strength) immediately after the joint was prepared and the joint strength after the following cycle test were measured and evaluated based on the following evaluation criteria. The larger the value of the adhesive strength, the better, and 15 MPa or more is within the practical range. The larger the value of the evaluation standard, the better, and the value of the evaluation standard of 2 or less indicates that it is defective.

6: 40 MPa or more 5: 30 MPa or more and less than 40 MPa 4: 20 MPa or more and less than 30 MPa 3: 15 MPa or more and less than 20 MPa 2: 5 MPa or more and less than 15 MPa 1: less than 5 MPa

<Cold heat cycle test>
After holding the bonded body at −40 ° C. for 30 minutes, holding it at 25 ° C. for 15 minutes, and holding it at 150 ° C. for 30 minutes was defined as one cycle, and 500 cycles of storage were carried out. After that, evaluation was performed using the same procedure and criteria as the above-mentioned bonding strength evaluation method. Furthermore, as a long-term resistance test, a similar evaluation after 1000 cycles was performed.

The bonding paste of Comparative Example could not be printed when the metal particles were contained in a high concentration (Comparative Examples 1, 5, and 7). Printing became possible by reducing the metal particle concentration, but the bonding strength of the obtained bonded body was extremely low, and when observing the sample destroyed after the die shear test, the interface between the gold-plated SiC chip and the bonded layer was observed. Was destroyed in.
On the other hand, the bonding paste of the example has excellent printability even when the metal particles are contained in a high concentration, the bonding strength of the obtained bonded body is very high, and even after the thermal cycle test is performed. It was confirmed that the decrease in joint strength was suppressed. In Examples 1 to 39, the samples after the evaluation of the bonding strength were immersed in toluene, the remaining organic substances were extracted and concentrated, and the IR was measured. As a result, they belonged to the amide bond from all the samples. The peak was detected, and it was confirmed that a polyamide obtained by condensing the polyvalent fatty acid (B) and the polyamine (C) was formed in the conjugate.

Claims (15)

A metal particle-containing composition comprising metal particles (A) having an average particle diameter of 1 nm to 1000 nm, a polyunsaturated fatty acid (B), and a polyamine (C). The metal particle-containing composition according to claim 1, wherein the polyvalent fatty acid (B) has 20 to 80 carbon atoms and the polyamine (C) has 20 to 80 carbon atoms. The metal particle-containing composition according to claim 1 or 2, wherein the polyunsaturated fatty acid (B) contains divalent and / or trivalent fatty acids. The metal particle-containing composition according to any one of claims 1 to 3, wherein the polyamine (C) contains a diamine and / or a triamine. The metal particle-containing composition according to any one of claims 1 to 4, wherein the polyunsaturated fatty acid (B) and / or the polyamine (C) has a branched and / or cyclic structure. When the valence of the polyvalent fatty acid (B) is m and the valence of the polyamine (C) is n, either the polyvalent fatty acid (B) has an m-valent hydrocarbon group (D) or the polyamine (C) has a valence of m. The metal particle-containing composition according to any one of claims 1 to 5, which has an n-valent hydrocarbon group (E). The metal particle-containing composition according to claim 6, wherein the m-valent hydrocarbon group (D) has 30 to 60 carbon atoms and / or the n-valent hydrocarbon group (E) has 30 to 60 carbon atoms. The metal particles (A) contain 0.05 parts by mass to 1 part by mass of the polyvalent fatty acid (B) and / or polyamine (C) 0.05 parts by mass to 1 part by mass with respect to 100 parts by mass. The metal particle-containing composition according to any one of claims 1 to 7. Contains 0.1 part by mass to 0.5 part by mass of polyvalent fatty acid (B) and / or 0.1 part by mass to 0.5 part by mass of polyamine (C) with respect to 100 parts by mass of metal particles (A). The metal particle-containing composition according to claim 8, wherein the composition comprises. The metal particle-containing composition according to any one of claims 1 to 9, wherein the metal particles (A) have an average particle size of 180 nm to 400 nm. The metal particle-containing composition according to claim 10, wherein the metal particles (A) have an average particle size of 200 nm to 300 nm. A bonding paste containing the metal particle-containing composition according to any one of claims 1 to 11 and the dispersion medium (F). The ratio of the mass of the metal particles (A) to the sum of the masses of the metal particles (A), the polyvalent fatty acid (B), the polyamine (C), and the dispersion medium (F) is 80% by mass to 95% by mass. The bonding paste according to claim 12. A bonded body in which a first bonded portion and a second bonded portion are bonded via a bonding layer, and the bonding layer is a layer formed by the bonding paste according to claim 12 or 13. Joined body. A method for manufacturing a bonded body in which a first bonded portion and a second bonded portion are bonded via a bonding layer, and the metal particles (A) having an average particle diameter of 1 nm to 1000 nm are multivalent. A bonding paste containing a fatty acid (B), a polyamine (C), and a dispersion medium (F) is applied to the first bonded portion, and the second bonded portion is placed and sintered. A method for manufacturing a bonded body, which comprises a step.