JP6928507B2 - Material for metal bonding - Google Patents

Description

The present invention relates to a metal bonding material used for bonding an adherend (for example, an aluminum material) and another adherend (for example, an aluminum material or a copper material).

Conventionally, brazing joining has been widely adopted as a joining method for products having a large number of fine joints, such as heat exchangers and machine parts made of Al (including aluminum and aluminum alloys; the same applies hereinafter).

Brazing joining is a method of melting brazing (alloy), which has a lower melting point than the material that constitutes the adherend and other adherends, and joining the adherend itself as a kind of adhesive without melting it. Say.

However, when the adherend and the material constituting the other adherend are Al material, the surface of the Al material is usually covered with a strong oxide film, so that the surface of the Al material is usually covered with a strong oxide film. It is necessary to remove this oxide film.

As a method for removing the oxide film existing on the surface of the Al material, a method using a flux is generally mentioned. A typical example of the flux component is an organic acid such as a carboxylic acid, and the flux component reacts with the oxide film component to remove the oxide film.

In the method using flux, the oxide film is removed, and the adherend can be normally bonded to another adherend. On the other hand, if the flux component remains on the surface of the Al material, there is a problem that the Al material is corroded.

In recent years, a method (fluxless brazing joining) of joining an adherend to another adherend without using flux has been proposed in a vacuum or an inert gas. However, in fluxless brazing joints, local joint defects are likely to occur on the joint surface.

Therefore, after interposing a wax (alloy) between the adherend and the other adherend so as not to cause a joint defect on the joint surface, the adherend and the other adherend are inactive. A method of heat treatment in a gas atmosphere has been proposed.

For example, in Patent Document 1, a brazing material sheet for surface bonding is interposed between the bonding surfaces of two Al materials, and the two Al materials are brazed and bonded in an inert gas atmosphere without using flux. Is disclosed.

The brazing material sheet for surface bonding according to Patent Document 1 uses an aluminum alloy containing a predetermined amount of Si and Mg as a core material and an aluminum alloy containing a predetermined amount of Si, Li, Be and Mg as a brazing material, and clads each of them. It is described that it is composed of.

Japanese Unexamined Patent Publication No. 2016-112585

However, it is described that the sintering temperature (heat treatment temperature) for joining two Al materials using the brazing material sheet for face bonding disclosed in Patent Document 1 is as high as about 600 ° C. ..

For this reason, there is a problem that the two Al materials that are the adherends are deformed due to the high bonding temperature, and a problem that the two Al materials that are the adherends are burnt down and softened. And so on.

The present invention has been made in view of the above circumstances, and even if the sintering temperature (heat treatment temperature) is relatively low (about 400 ° C.), the adherend and another adherend can be separated from each other. It is an object of the present invention to provide a material for metal bonding that can be suitably bonded.

In order to solve the above problems, the metal bonding material according to the present invention contains metal fine particles (P) containing metal fine particles (P1) having an average primary particle size in the range of 2 to 500 nm, and divalent or higher valent alcohol. The content of the compound (X) containing the organic solvent (S) and the compound (X) containing the group 2 element is equal to the total amount (g) of the metal fine particles (P1). The concentration of the Group 2 element is 300 to 80,000 μg / g.

Further, the compound (X) containing a Group 2 element contains at least one Group 2 element among beryllium, magnesium, calcium, strontium, and barium, and is a carbonate compound, a hydroxide salt compound, and silicic acid. It is preferably at least one selected from the salt compound and the organic acid salt compound.

Further, the compound (X) containing a Group 2 element is preferably a carbonate compound containing calcium.

Alcohols of divalent or higher are glycerin, 1,1,1-tris (hydroxymethyl) ethane, 1,2,4-butanetriol, 1,2,3-hexanetriol, 1,2,6-hexanetriol. , And at least one trihydric alcohol selected from 2-ethyl-2-hydroxymethyl-1,3-propanediol; polyglycerin, treitol, erythritol, pentaerythritol, pentitol. , 1-propanol, 2-propanol, 2-butanol, 2-methyl 2-propanol, xylitol, ribitol, arabitol, hexitol, mannitol, sorbitol, zulcitol, glycerin aldehyde, dioxyacetone, treose, elittlerose, erythrose, arabinose , Ribos, ribulose, xylose, xylulose, liquose, glucose, fructose, mannose, idose, sorbitol, growth, talose, tagatos, galactose, allose, altrose, lactos, isomaltos, glucoheptose, At least one polyhydric alcohol selected from heptose, maltotriose, lacturose, and trehalose; preferably at least one selected from.

Further, it is preferable that the divalent or higher alcohol is at least one selected from glycerin among trihydric alcohols and polyglycerin among polyhydric alcohols.

Further, it is preferable that the metal used as a raw material for the metal fine particles (P1) is copper.

According to the present invention, the adherend can be suitably bonded to another adherend even at a sintering temperature (heat treatment temperature) due to relatively low heating (about 400 ° C.).

<Material for metal bonding>
The metal bonding material (dispersion solution of metal fine particles (P)) according to the present invention includes metal fine particles (P) containing metal fine particles (P1) having an average primary particle size in the range of 2 to 500 nm, and divalent or higher valent metal fine particles (P). It contains an organic solvent (S) containing an alcohol and a compound (X) containing a Group 2 element.

(1) Compound (X) containing a Group 2 element
In the present invention, the compound (X) containing a Group 2 element is contained as a material for metal bonding.
As a result, the adherend and other adherends can be suitably bonded even at a sintering temperature (heat treatment temperature) due to relatively low heating (about 400 ° C.).

When metal fine particles (P1) having an average primary particle size in the range of 2 to 500 nm and alcohol having a divalent value or higher coexist as a material for metal bonding, the metal fine particles (P1) (for example, copper) at a temperature of 200 ° C. or higher The catalytic effect of the fine particles) is preferably exhibited, and divalent or higher alcohols are decomposed to generate organic acids such as carboxylic acids and hydrogen.

In the present invention, as a material for metal bonding, metal fine particles (P1) having an average primary particle size in the range of 2 to 500 nm, a divalent or higher alcohol, and a compound (X) containing a Group 2 element coexist. The catalytic effect of the metal fine particles (P1) (for example, copper fine particles) is preferably exhibited at a temperature of relatively low heating (about 400 ° C.), and divalent or higher alcohols are decomposed to decompose organic substances such as carboxylic acids. Acids and hydrogen are produced.
The Group 2 element (for example, calcium) is liberated from the compound (X) containing the Group 2 element by the action of an organic acid such as a carboxylic acid or hydrogen thus produced.
As a result, it is considered that the oxide film existing on the surface of the Al material is removed by the reducing action of the liberated Group 2 element.

Actually, 60 g of copper fine particles (P1) which are metal fine particles having an average primary particle size of 50 nm, 40 g of glycerin which is a trivalent alcohol, and 45 mg of calcium carbonate (X) which is a compound (X) containing a Group 2 element (metal fine particles (metal fine particles (P1)). A calcium concentration of 300 μg / g with respect to the total amount (g) of P1) was placed in a container and kneaded to obtain a dispersion solution (material for metal bonding) of paste-like metal fine particles.
A part of the metal bonding material thus obtained was placed in an aluminum dish, heated at a rate of 10 ° C./min, and sintered at a temperature of 400 ° C. for 20 minutes. Then, the furnace was cooled to room temperature, and a part of the sintered film formed on the aluminum dish was collected as a sample. When the sample was subjected to elemental analysis using EPMA (electron probe microanalyzer), Al was detected in addition to Cu.
From this, due to the fact that the compound (X) containing the Group 2 element was used in a predetermined amount (300 to 80,000 μg / g as the concentration of the Group 2 element), the oxide film existing on the surface of the aluminum dish was formed. Experimental results have also been obtained showing that Al was removed and Al was diffused into the sintered body to form an alloy of Cu and Al.

Here, "Group 2 element" is a general term for elements belonging to Group 2 in the periodic table, and beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba). , And radium (Ra). Among these, calcium (Ca) is preferable because the effect of the reducing action of the liberated Group 2 element is high.

In the present invention, the compound (X) containing a Group 2 element is a second compound of at least one of beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba). It is preferably at least one selected from carbonate compounds, hydroxide salt compounds, silicate compounds, and organic acid salt compounds containing group elements.

The carbonate compound is not particularly limited as long as it is a carbonate compound containing at least one of beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba). For example, beryllium carbonate, magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate and the like can be mentioned.

The hydroxide salt compound may be a hydroxide salt compound containing at least one of beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba). The present invention is not particularly limited, and examples thereof include beryllium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, and barium hydroxide.

The silicate compound is particularly a hydroxide salt compound containing at least one of beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba). Examples include, but are not limited to, berylium silicate, magnesium silicate, calcium silicate, strontium silicate, barium silicate and the like.

The organic acid salt compound is particularly limited as long as it is an organic acid salt compound containing at least one of beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba). However, for example, beryllium oxalate, magnesium oxalate, calcium oxalate, strontium oxalate, barium silicate and the like can be mentioned.

In the present invention, the content of the compound (X) containing the Group 2 element is 300 to 80,000 μg / g as the concentration of the Group 2 element with respect to the total amount (g) of the metal fine particles (P1).

When the content of the compound (X) containing the Group 2 element is in the above range (300 to 80,000 μg / g as the concentration of the Group 2 element), the reducing action of the liberated Group 2 element causes the reducing action. The effect of removing the oxide film existing on the surface of the Al material can be fully exerted, and the adherend (for example, heat treatment temperature) even at a sintering temperature (heat treatment temperature) due to relatively low heating (about 400 ° C.) The aluminum material) and another adherend (for example, aluminum material or copper material) can be suitably bonded, and a desired bonding strength can be obtained.

When the content of the compound (X) containing the Group 2 element is less than the above range (the concentration of the Group 2 element is less than 300 μg / g), the amount of the liberated Group 2 element is too small. Due to the reducing action of the liberated Group 2 elements, the effect of removing the oxide film existing on the surface of the Al material cannot be sufficiently exerted, and the adherend (for example, aluminum material) and other adherends (for example, aluminum material) and other adherends (for example) For example, an aluminum material or a copper material) cannot be suitably bonded, and a desired bonding strength may not be obtained.

When the content of the compound (X) containing the Group 2 element exceeds the above range (the concentration of the Group 2 element exceeds 80,000 μg / g), the amount of the liberated Group 2 element is too large. Although the effect of removing the oxide film existing on the surface of the Al material is recognized by the reducing action of the liberated Group 2 element, the liberated Group 2 element is an adherend (for example, aluminum material) or another adherend. It produces a body (eg, aluminum or copper) and a compound (eg, Al ₄ Ca, Cu ₅ Ca), and instead produces an adherend (eg, aluminum) and another adherend (eg, aluminum). Alternatively, it may not be able to be suitably bonded to the copper material), and the desired bonding strength may not be obtained.

(2) Metal fine particles (P)
In the present invention, as a material for metal bonding, metal fine particles (P) containing metal fine particles (P1) having an average primary particle size in the range of 2 to 500 nm are contained.

(2-1) Metal fine particles (P1)
In the present invention, the metal used as a raw material for the metal fine particles (P1) is not particularly limited, but copper (Cu) is preferably used, and gold (Au), silver (Ag), platinum (Pt), and palladium (Pt) are also preferably used. Precious metals such as Pd) can also be preferably used.

When copper (Cu) is used as a raw material for metal fine particles (P1), sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), strontium (Sr), and chromium are unavoidable impurities. Each metal such as (Cr), iron (Fe), nickel (Ni), zinc (Zn), boron (B), silicon (Si), lead (Pb), and phosphorus (P) is added to the metal fine particles (P1). 30 μg / g or less may be contained in each of the total amount (g) of the above.

In the present invention, the metal fine particles (P1) used have an average primary particle size in the range of 2 to 500 nm. As a result, the catalytic effect of the metal fine particles (P1), which decomposes the divalent or higher alcohol contained in the organic solvent (S), can be suitably exhibited.

If the average primary particle size of the metal fine particles (P1) is less than the above range (less than 2 nm), advanced particle size control technology is involved, which may lead to an increase in manufacturing cost and metal fine particles (P1). P) tends to aggregate in the dispersion solution (in the material for metal bonding), is difficult to disperse uniformly, and may be inferior in storage stability.

On the other hand, when the average primary particle size of the metal fine particles (P1) exceeds the above range (more than 500 nm), the surface area is relatively reduced, so that the dihydric or higher alcohol contained in the organic solvent (S) There is a possibility that the catalytic effect of the metal fine particles (P1), which decomposes the metal particles (P1), is inferior.

Here, the "primary particle size" refers to the diameter of each primary particle constituting the secondary particle. The primary particle size can be measured using a scanning electron microscope (SEM).

Further, the "average primary particle size" refers to an average value calculated by individually measuring the diameters of a plurality of primary particles selected as measurement targets and dividing each measured value by the number of particles.

Specifically, using a scanning electron microscope (SEM) (manufactured by Hitachi High-Technology Co., Ltd., product name: SU8020), observation is performed under conditions of an acceleration voltage of 3 kV and a magnification of 200,000 times, and metal fine particles to be measured (manufactured by Hitachi High Technology Co., Ltd., product name: SU8020). Acquire the SEM image of P1). Twenty metal fine particles (P1) are arbitrarily selected from the acquired SEM images, the diameters of the primary particles of the selected metal fine particles (P1) are measured, the average of each measured value is calculated, and the average primary is calculated. Find the particle size.

(2-2) Metal fine particles (P2)
The metal fine particles (P) used in the present invention are composed of only the metal fine particles (P1) having an average primary particle size in the range of 2 to 500 nm as described above, and in addition to the metal fine particles (P1), further have an average primary particle size. It may be composed of a mixture of metal fine particles (P2) having a particle size in the range of 0.5 to 50 μm.

The metal fine particles (P) used in the present invention include metal fine particles (P1) having an average primary particle size in the range of 2 to 500 nm and metal fine particles (P2) having an average primary particle size in the range of 0.5 to 50 μm. When the above are allowed to coexist, nano-sized metal fine particles (P1) can be suitably interposed between the micron-sized metal fine particles (P2).

As a result, the free flow of the nano-sized metal fine particles (P1) is effectively restricted, and the metal fine particles (P1) are stably mixed in the dispersed solution of the metal fine particles (P) in an appropriate dispersed state. Can be done.

When the average primary particle size of the metal fine particles (P2) is less than the above range (less than 0.5 μm), the nano-sized metal fine particles (P1) are free in the dispersion solution of the metal fine particles (P). There is a risk that the effect of limiting the flow cannot be fully exerted.

On the other hand, when the average primary particle size of the metal fine particles (P2) exceeds the above range (more than 50 μm), streaky coating defects occur during printing, and some of the metal fine particles cannot be joined, resulting in reliability. It can be damaged.

Here, the "average primary particle size" refers to a particle size having a cumulative frequency of 50% as measured by a laser diffraction type particle size distribution meter.

In the present invention, the metal used as a raw material for the metal fine particles (P2) is not particularly limited, but gold (Au), silver (Ag), platinum (Pt), palladium (Pd), titanium (Ti), iron (Fe), and the like. Cobalt (Co), Nickel (Ni), Copper (Cu), Tantal (Ta), Tungsten (W), Aluminum (Al), Zinc (Zn), Indium (In), Tin (Sn), Lead (Pb), One or more selected from bismuth (Bi) can be used. Of these, copper (Cu) is particularly preferably used.

(3) Polymer dispersant (D)
The metal fine particles (P1) contained in the metal fine particles (P) used in the present invention and having an average primary particle size in the range of 2 to 500 nm may be formed by coating the surface thereof with a polymer dispersant (D). can.

By coating the surface of the metal fine particles (P1) with the polymer dispersant (D), aggregation of the metal fine particles (P1) in the dispersion solution of the metal fine particles (P) is prevented, and the dispersibility of the metal fine particles (P1) is prevented. Can be improved.

Here, the “coating” may mean covering at least a part of the surface of the metal fine particles (P1), and may cover the entire surface of the metal fine particles (P1).

The polymer dispersant (D) used in the present invention is not particularly limited as long as it is a compound having a property of being able to suitably coat the surface of metal fine particles (P1), but has an amide group (-CON =). Compounds are preferably used.

Examples of the compound having an amide group (-CON =) include N-methylacetamide, N-methylformamide, N-methylpropanamide, formamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidi. Non, N, N-dimethylformamide, 1-methyl-2-pyrrolidone, hexamethylphosphoric triamide, 2-pyrrolidone, alkyl-2-pyrrolidone, ε-caprolactam, and acetamide, polyvinylpyrrolidone, polyacrylamide, and N- One or more selected from vinyl-2-pyrrolidone can be used. Of these, polyvinylpyrrolidone is particularly preferably used.

The weight ratio (D / P1) of the polymer dispersant (D) used in the present invention and the metal fine particles (P1) to be coated is not particularly limited, but is in the range of 0.1 to 5.0. Is preferable.

When the weight ratio (D / P1) of the polymer dispersant (D) to the metal fine particles (P1) is less than the above range, the polymer dispersant (P1) is used to coat the surface of the metal fine particles (P1). Due to the fact that the amount of D) is too small, aggregation of the metal fine particles (P1) cannot be suitably prevented, and the dispersibility of the metal fine particles (P1) may be lowered.

On the other hand, when the weight ratio (D / P1) of the polymer dispersant (D) and the metal fine particles (P1) exceeds the above range, a dispersion solution of the metal fine particles (P) is used with the adherend. In the process of applying to any or each of the adherends of No. 1 and performing sintering by heat treatment (sintering process), the polymer dispersant (D) is not suitably decomposed and remains in the bonding layer. , The desired bonding layer may not be formed.

In the present invention, the method of coating the surface of the metal fine particles (P1) with the polymer dispersant (D) is not particularly limited, but it is difficult to directly measure the thickness of the coated polymer dispersant (D). Therefore, a method of measuring the coating amount using a carbon / sulfur concentration analyzer can be adopted.

Specifically, using a carbon / sulfur concentration analyzer, the sample to be measured is introduced into the reaction vessel, oxygen gas is passed through the reaction vessel, and the temperature is raised to a high temperature state, and the carbon component contained in the sample to be measured is contained. Is taken out in the state of carbon dioxide.

The concentration of the extracted carbon dioxide is measured by a carbon dioxide detector, the amount of carbon is calculated from the concentration, and the weight of the polymer dispersant (D) used is calculated from the amount of carbon. The amount of the polymer dispersant (D) actually coated on the surface of P1) can be determined.

(4) Organic solvent (S)
The organic solvent (S) used in the present invention is composed of a divalent or higher alcohol (S1 to S3), and in addition to the divalent or higher alcohol (S1 to S3), a lower boiling point organic solvent (S). S4) can also be mixed and configured.

Further, the organic solvent (S) used in the present invention may be formed by appropriately mixing an amine solvent (S5), if necessary.

Since the "divalent or higher alcohols (S1 to S3)" have a reducing property with respect to the metal fine particles (P1), the dispersion solution of the metal fine particles (P) is used as either an adherend or another adherend. Alternatively, the sintering of the metal fine particles (P1) can be suitably promoted in the process of applying the coating to each of them and performing the sintering by heat treatment (sintering process).

Here, "divalent or higher alcohol" refers to an alcohol having two or more hydroxyl groups (-OH) in one molecule.

The dihydric or higher alcohols (S1 to S3) include a dihydric alcohol (S1) having two hydroxyl groups (-OH) in one molecule and three hydroxyl groups (-OH) in one molecule. It can be classified into a trihydric alcohol (S2) and a polyhydric alcohol (S3) having four or more hydroxyl groups (-OH) in one molecule.

(4-1) Divalent alcohol (S1)
The dihydric alcohol (S1) is not particularly limited, but for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1 , 4-Butanediol, 2,3-Butanediol, 2-Butane-1,4-diol, Pentandiol, Hexadiol, and Octanediol can be used alone or in combination of two or more. Of these, ethylene glycol and diethylene glycol are particularly preferably used.

(4-2) Trihydric alcohol (S2)
The trihydric alcohol (S2) is not particularly limited, and is, for example, glycerin (glycerol), 1,1,1-tris (hydroxymethyl) ethane, 1,2,4-butanetriol, 1,2,3-hexane. One or more selected from triol, 1,2,6-hexanetriol, and 2-ethyl-2-hydroxymethyl-1,3-propanediol can be used. Of these, glycerin (glycerol) is particularly preferably used.

(4-3) Multihydric alcohol (S3)
The polyhydric alcohol is not particularly limited, and is, for example, polyglycerin, threitol, erythritol, pentaerythritol, pentitol, 1-propanol, 2-propanol, 2-butanol, 2-methyl 2-. Propanol, xylitol, ribitol, arabitol, hexitol, mannitol, sorbitol, zulcitol, glycerin aldehyde, dioxyacetone, threitol, elittlerose, erythrose, arabinose, ribose, ribulose, xylose, xylrose, lixose, glucose, fructose , Mannitol, Idoth, Sorbitol, Growth, Threitol, Tagatose, Galactose, Allose, Altrose, Lactose, Isomartose, Glyceropheth, Heptose, Maltotriose, Lactulose, and Threitol. One kind or two or more kinds can be used. Among these, polyglycerin is particularly preferably used.

The content of the divalent or higher alcohols (S1 to S3) is preferably 20 to 100% by weight with respect to 100% by weight of the total amount of the organic solvent (S).

(4-4) Low boiling organic solvent (S4)
The "low boiling point organic solvent (S4)" is used to adjust the viscosity of the dispersion solution of the metal fine particles (P), and the dispersion solution of the metal fine particles (P) can be used as either an adherend or another adherend. Alternatively, by adjusting the viscosity so that it is suitable for coating on each of them, it is difficult for the liquid to drip, and even advanced coating such as pattern formation can be coated with high accuracy.

Here, the "low boiling point organic solvent (S4)" is an organic compound that is liquid at normal temperature and has a boiling point of 60 to 120 ° C. at normal pressure (the boiling point means the boiling point at normal pressure; the same applies hereinafter). It refers to an organic compound with a relatively low boiling point.

Examples of the low boiling point organic solvent (S4) include a monohydric alcohol having one hydroxyl group (-OH) in one molecule, an ether having one ether bond (C-OC) in one molecule, and an ether. A ketone having one carbonyl group (C = O) in one molecule is preferably used.

The monohydric alcohol is not particularly limited, but is, for example, methanol (64.7 ° C.), ethanol (78 ° C.), 1-propanol (97.15 ° C.), 2-propanol (82.4 ° C.), 2-methyl. 2-Propanol (83 ° C.), 2-butanol (100 ° C.) and the like are preferably used.

The ether is not particularly limited, but for example, dipropyl ether (89 ° C.), diisopropyl ether (68 ° C.), t-amylmethyl ether (85 ° C.), allyl ether (94 ° C.) and the like are preferably used.

The ketone is not particularly limited, but for example, acetone (56.5 ° C.), methyl ethyl ketone (79.5 ° C.), diethyl ketone (100 ° C.) and the like are preferably used.

The content of the low boiling point organic solvent (S4) is preferably 0 to 80% by weight with respect to 100% by weight of the total amount of the organic solvent (S).

(4-5) Amine-based solvent (S5)
Since the "amine-based solvent" has a reducing property with respect to the metal fine particles (P1), a dispersion solution of the metal fine particles (P) is applied to either or each of the adherend and the other adherend. In the process of sintering by heat treatment (sintering process), the sintering of metal fine particles (P1) can be suitably promoted.

As the amine-based solvent (S5), aliphatic primary amines, aliphatic secondary amines, aliphatic tertiary amines, aliphatic unsaturated amines, alicyclic amines, aromatic amines, and alkanol amines are preferably used. Specific examples thereof include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, n-propylamine, di-n-propylamine, tri-n-propylamine, n-butylamine, di-n-butylamine, and tri. -N-butylamine, t-propylamine, t-butylamine, ethylenediamine, propylenediamine, tetramethylenediamine, tetramethylpropylenediamine, pentamethyldiethylenetriamine, mono-n-octylamine, mono-2ethylhexylamine, di-n-octyl Amine, di-2ethylhexylamine, tri-n-octylamine, tri-2ethylhexylamine, triisobutylamine, trihexylamine, triisooctylamine, triisononylamine, triphenylamine, dimethylcoconatamine, dimethyloctyl Amines, dimethyldecylamines, dimethyllaurylamines, dimethylmyristylamines, dimethylpalmitylamines, dimethylstearylamines, dimethylbehenylamines, dilaurylmonomethylamines, diisopropylethylamines, methanolamines, dimethanolamines, trimethanolamines, ethanolamines, diethanolamines. , Triethanolamine, propanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, butanolamine, N-methylethanolamine, N-methyldiethanolamine, N, N-dimethylethanolamine, N-ethylethanolamine, N-ethyl Examples thereof include diethanolamine, N, N-diethylethanolamine, Nn-butylethanolamine, Nn-butyldiethanolamine, and 2- (2-aminoethoxy) ethanol.

The content of the amine solvent (S5) is preferably 0.3 to 30% by weight with respect to 100% by weight of the total amount of the organic solvent (S).

<Joined structure>
In the present invention, the above-mentioned metal bonding material (dispersion solution of metal fine particles (P)) according to the present invention is placed between an adherend (aluminum material) and another adherend (aluminum material or copper material). The bonded structure can be manufactured by arranging in.

A method for producing a bonded structure through a (1) coating step, (2) drying step, and (3) sintering step using the metal bonding material (dispersion solution of metal fine particles (P)) according to the present invention. An example will be described below.

(1) Coating step In the coating step, the above-mentioned metal bonding material (dispersion solution of metal fine particles (P)) according to the present invention is applied to an adherend (aluminum material) and another adherend (aluminum material or copper material). ), Or by applying to each of them, this is a step of arranging the adherend (aluminum material) and another adherend (aluminum material or copper material).

The above-mentioned metal bonding material (dispersion solution of metal fine particles (P)) according to the present invention contains metal fine particles (P) containing metal fine particles (P1) having a specific average primary particle size, and divalent or higher alcohol. It is formed by dispersing it in the containing organic solvent (S).
In the present invention, the method for dispersing the metal fine particles (P) in the organic solvent (S) is not particularly limited, but a known mixer, kneader, kneader, or the like can be used.

The weight ratio (P / S) of the metal fine particles (P) and the organic solvent (S) contained in the metal bonding material (dispersion solution of the metal fine particles (P)) according to the first embodiment of the present invention is determined. It is preferably in the range of 10/90 to 70/30 from the viewpoint of being preferably arranged between the adherend and another adherend.

When the weight ratio (P / S) of the metal fine particles (P) and the organic solvent (S) is less than the above range, the amount of the organic solvent (S) is too large and the viscosity of the dispersion solution is higher than desired. Due to the low value, when the metal bonding material (dispersion solution of metal fine particles (P)) is applied to either the adherend or another adherend, or to each of them, dripping is likely to occur. The shape stability is poor, advanced coating such as pattern formation is difficult, and there is a risk that it will be difficult to form a desired bonding layer in the sintering step described later.

When the weight ratio (P / S) of the metal fine particles (P) and the organic solvent (S) exceeds the above range, the amount of the organic solvent (S) is too small and the metal fine particles (P) are powdery. When the metal bonding material (dispersion solution of metal fine particles (P)) is applied to one of the adherends and other adherends, or to each of them, it is easy to exist as it is and it is difficult to make it into a paste. In addition to the possibility that the coating method may be limited, the organic solvent (S) is depleted before reaching the sintering temperature at which the bonding layer is formed in the process of sintering by heat treatment (sintering process). There is a risk of sintering (vaporizing).

In the present invention, the weight ratio (P / S) of the metal fine particles (P) and the organic solvent (S) is such that the metal bonding material (dispersion solution of the metal fine particles (P)) is used as an adherend and another substrate. It can be changed as appropriate depending on any of the bodies or the method of applying to each.

For example, when performing advanced coating such as pattern formation on an adherend and other adherends, a shape such that the metal bonding material (dispersion solution of metal fine particles (P)) does not easily drip. Since stability is required, the weight ratio (P / S) of the metal fine particles (P) and the organic solvent (S) is preferably in the range of 20/80 to 60/40.

In addition, when the adherend and other adherends are applied thinly over a wide area such as in the form of a sheet, characteristics such as ease of stretching the metal bonding material (dispersion solution of metal fine particles (P)). The weight ratio (P / S) of the metal fine particles (P) and the organic solvent (S) is preferably in the range of 10/90 to 30/70.

In the present invention, the method of applying the metal bonding material (dispersion solution of metal fine particles (P)) to either or each of the adherend and the other adherend is not particularly limited, but for example, a squeegee. Methods, screen printing, mask printing, inkjet printing, dispenser printing, spray coating, bar coating, knife coating, spin coating and the like.

(2) Drying step In the drying step, the metal bonding material (dispersion solution of metal fine particles (P)) arranged between the adherend and another adherend in the above (1) coating step is subjected to predetermined conditions. This is a step of performing drying such as pre-drying.

Under the drying conditions such as pre-drying performed in the drying step, the content of the metal fine particles (P) in the metal bonding material (dispersion solution of the metal fine particles (P)) is 100% by weight of the total amount of the metal bonding material. It is preferable to keep the material at a drying temperature of 110 ° C. for about 30 to 60 minutes under an inert gas or atmospheric gas atmosphere so that the weight is adjusted to 87 to 93% by weight.

(3) Sintering step In the sintering step, the metal bonding material is used as opposed to the metal bonding material (dispersion solution of metal fine particles (P)) that has been dried such as pre-dried in the above (2) drying step. This is a process of sintering by heat treatment or the like.

Sintering conditions such as heat treatment performed in the sintering process include, for example, a heat press machine with a built-in heater that sandwiches the adherend and another adherend, vacuums (reduces pressure), and performs 190- It is preferable to hold it at a heating temperature (sintering temperature) of 400 ° C. for about 10 to 120 minutes.
The sintering conditions such as heat treatment performed in the sintering step may be performed while pressurizing.

For example, in the coating step, a dispersion solution containing metal fine particles (P) containing copper fine particles (P1) having a specific average primary particle size and an organic solvent (S) containing divalent or higher alcohol was used. In the case, in the sintering step, the sintering of the copper fine particles (P1) is promoted as follows.

By heat treatment or the like performed in the sintering step, the surface of the copper fine particles (P1) is reduced with alcohol having a divalent value or higher, and sintering of the activated copper fine particles (P1) is promoted. On the other hand, the organic solvent (S) containing a divalent or higher alcohol preferably decomposes and evaporates (vaporizes).

In the present invention, a bonded structure having a bonded layer of a porous metal body can be produced through the above (1) coating step, (2) drying step, and (3) sintering step.

In the present invention, after the above (3) sintering step, if necessary, at a temperature of 190 to 400 ° C. under an atmospheric atmosphere or an atmosphere of an inert gas such as nitrogen and a reducing atmosphere such as hydrogen. It is preferable to perform the annealing treatment for about 1 to 30 hours.

By performing such an annealing treatment, strain due to residual stress in the bonding layer formed in the above (3) sintering step is appropriately relaxed, and the bonding strength of the bonding layer and the reliability of the bonding state at the bonding interface are improved. It can be further enhanced.

In the present invention, the thickness (L) of the bonding layer of the bonding structure produced through the above (1) coating step, (2) drying step, and (3) sintering step is in the range of 5 μm or more. preferable.

When the thickness (L) of the bonding layer is less than the above range (less than 5 μm), the thickness of the bonding layer is too thin, and the bonding layer is between the adherend and another adherend. Is liable to occur in that the joint layer is not partially formed, which may reduce the joint strength of the joint layer and also reduce the reliability of the joint state of the joint interface.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
The test methods performed in this example and the comparative example are as follows.

(1) Average primary particle size of metal fine particles (P1) Using a scanning electron microscope (SEM) (manufactured by Hitachi High Technology, product name: SU8020), observation is performed under conditions of an acceleration voltage of 3 kV and a magnification of 200,000 times. , An SEM image of the metal fine particles (P1) to be measured was acquired. Twenty metal fine particles (P1) are arbitrarily selected from the acquired SEM images, the diameters of the primary particles of the selected metal fine particles (P1) are measured, the average of each measured value is calculated, and the average primary is calculated. The particle size was determined.

(2) Evaluation test of the joint The evaluation of the joint was performed by a tensile test.
The tensile test was performed according to JIS Z2241. The temperature at the time of the test was 23 ° C., the gauge distance was 25 mm, and the strain rate was 5 mm / min. The test was carried out at n = 5, and the average value of n = 3 was used except for the maximum and minimum values. The nominal tensile strength (MPa) was defined as the maximum nominal stress by dividing the maximum load during the tensile test by the bonding area of the copper nanopaste.

(Example 1)
(Separation / recovery process of metal fine particles (P))
10 g of polyvinylpyrrolidone (PVP, number average molecular weight; about 3,500) as a polymer dispersant (D) was added to 99.3 ml of distilled water and dissolved in an aqueous solution, and hydroxide was used as a raw material for metal fine particles (P1). 29.268 g of cupric (Cu (OH) ₂ , particle size range: 0.1 to 100 μm) was added and stirred to prepare an aqueous solution of cupric hydroxide.

The liquid temperature of the cupric hydroxide aqueous solution prepared as described above was adjusted to 20 ° C., _{and 150 mmol of sodium borohydride (NaBH 4} ) and 480 mmol of sodium hydroxide (NaOH) were stirred in a nitrogen gas atmosphere. 20.73 ml of an aqueous solution containing and was added dropwise, and a reduction reaction was carried out with stirring for 45 minutes to generate metal fine particles (P1) coated with the polymer dispersant (D) in the mixed solution.
The reduction reaction was terminated when the generation of hydrogen gas from the reaction system was completed.

To the mixed solution of the metal fine particles (P1) coated with the polymer dispersant (D) produced as described above, _{66 ml of chloroform (CHCl 3} ) was added as an aggregation accelerator, and the mixture was stirred for several minutes. The metal fine particles (P1) coated with the polymer dispersant (D) were precipitated by allowing to stand for a minute.

A mixed solution containing the solid content of the metal fine particles (P1) coated with the polymer dispersant (D), which was precipitated as described above, was supplied to the centrifuge to perform solid-liquid separation, and the polymer dispersant was performed. The solid content containing the metal fine particles (P1) coated with (D) was recovered.

Further, methanol is added to the solid content containing the metal fine particles (P1) coated with the recovered polymer dispersant (D), stirred, supplied to a centrifuge, solid-liquid separated, and the polymer is subjected to solid-liquid separation. The metal fine particles (P1) coated with the dispersant (D) were washed with methanol.

Methanol washing was repeated several times as described above to separate and recover the metal fine particles (P1) coated with the polymer dispersant (D). Then, vacuum drying was carried out for 7 hours to obtain dried metal fine particles (P1). The degree of vacuum during vacuum drying was -80 kPa or less, assuming that the atmospheric pressure was 0 kPa.

Here, a part of the dried metal fine particles (P1) coated with the polymer dispersant (D) obtained through the above separation / recovery steps is collected and coated with the polymer dispersant (D). The primary particle size of the metal fine particles (P1) was measured, and the average primary particle size was calculated to be 50 nm.

(Step of obtaining a dispersion solution of metal fine particles (P))
_{Glycerin (glycerol) (C 3} H ₅ (OH) ₃ , boiling point; which is a trivalent alcohol as an organic solvent (S) containing 60 g of metal fine particles (P1) obtained as described above and a divalent or higher alcohol. 40 g (290 ° C.) and 45 mg of calcium carbonate (calcium concentration is 300 μg / g with respect to the total amount (g) of the metal fine particles (P1)) as the compound (X) containing a Group 2 element are placed in a container and centrifuged. It was put into a smelter (manufactured by Shinky Co., Ltd., product name: ARE-250) and kneaded by repeating the conditions of 2000 rpm × 3 minutes four times to obtain a dispersion solution of paste-like metal fine particles (P).

(Applying step of dispersion solution of metal fine particles (P))
Preparation of tensile test piece The material is 301 SS / 3003 Al manufactured by Bimetal Japan Co., Ltd. (0.4 mm thick SUS and 0.4 mm thick aluminum bonded together, hereinafter aluminum member) is scraped to reduce the thickness of the Al layer. A material cut to a thickness of 0.1 mm was used as a material. As the material, a member obtained by cutting the No. 13B test piece specified in JIS Z2201 in about half was prepared as shown below. In addition, a product (hereinafter referred to as a copper member) having the same shape and made of oxygen-free copper having a thickness of 0.4 mm was also prepared.
A paste-like dispersion solution of the metal fine particles (P) obtained in the step of obtaining the dispersion solution of the metal fine particles (P) is applied to a designated area of the aluminum member with a stainless metal mask (8 mm square). A 200 mm square metal mask having an opening (100 μm thickness) was placed and applied by the squeegee method.

(Drying process)
The metal fine particles (P) in the dispersion solution of the metal fine particles (P) are placed on a hot plate with the coated surface of the aluminum member facing up and held at a drying temperature of 110 ° C. for about 30 to 60 minutes in an air atmosphere. The content was adjusted to about 90% by weight with respect to 100% by weight of the total amount of the dispersion solution of the metal fine particles (P), and pre-dried.

(Sintering process)
After that, the aluminum member and the copper member (dimensions are the same as those printed with copper nanopaste) are superposed on the coated surface of the aluminum member by 10 mm.

Next, (A) aluminum member and aluminum member, and (B) aluminum member and copper member are set in a heat press machine (manufactured by Imoto Seisakusho Co., Ltd., product name: IMC-1A1C type), respectively, under a nitrogen gas atmosphere. Then, the temperature was raised at a rate of 10 ° C./min under a pressure of 10 MPa, and sintering was performed by pressure heat treatment at a temperature of 400 ° C. for 20 minutes.

After that, the furnace is cooled to room temperature, and the joint structure (A) in which the aluminum member and the aluminum member are joined via the sintered body and the joint structure (A) in which the aluminum member and the copper member are joined via the sintered body ( B) were prepared respectively.

Here, a tensile test was performed on the joint structure (A) between the aluminum member and the aluminum member and the joint structure (B) between the aluminum member and the copper member, which were produced respectively. The tensile test was performed according to JIS Z2241. The temperature at the time of the test was 23 ° C., the gauge distance was 25 mm, and the strain rate was 5 mm / min. The test was carried out at n = 5, and the average value of n = 3 was used except for the maximum and minimum values. The nominal tensile strength (MPa) was defined as the maximum nominal stress by dividing the maximum load during the tensile test by 64 mm ^2. The test results are shown in Table 1.

(Example 2)
In the step of obtaining the dispersion solution of the metal fine particles (P) of Example 1, the amount of the compound (X) containing the Group 2 element added was 500 μg / g with respect to the total amount (g) of the metal fine particles (P1). It is the same as that of Example 1 except that it is changed to.

(Example 3)
In the step of obtaining the dispersion solution of the metal fine particles (P) of Example 1, the amount of the compound (X) containing the Group 2 element added was 1000 μg / g with respect to the total amount (g) of the metal fine particles (P1). It is the same as that of Example 1 except that it is changed to.

(Example 4)
In the step of obtaining the dispersion solution of the metal fine particles (P) of Example 1, the amount of the compound (X) containing the Group 2 element added was 10000 μg / g with respect to the total amount (g) of the metal fine particles (P1). It is the same as that of Example 1 except that it is changed to.

(Example 5)
In the step of obtaining the dispersion solution of the metal fine particles (P) of Example 1, the amount of the compound (X) containing the Group 2 element added was 20000 μg / g with respect to the total amount (g) of the metal fine particles (P1). It is the same as that of Example 1 except that it is changed to.

(Example 6)
In the step of obtaining the dispersion solution of the metal fine particles (P) of Example 1, the amount of the compound (X) containing the Group 2 element added was 50,000 μg / g with respect to the total amount (g) of the metal fine particles (P1). It is the same as that of Example 1 except that it is changed to.

(Example 7)
In the step of obtaining the dispersion solution of the metal fine particles (P) of Example 1, the amount of the compound (X) containing the Group 2 element added was 80,000 μg / g with respect to the total amount (g) of the metal fine particles (P1). It is the same as that of Example 1 except that it is changed to.

(Example 8)
In the step of obtaining the dispersion solution of the metal fine particles (P) of Example 1, the type of the compound (X) containing the Group 2 element was changed to beryllium carbonate, and the amount of the compound (X) containing the Group 2 element added was changed. The same as in Example 1 except that the beryllium concentration was changed to 500 μg / g with respect to the total amount (g) of the metal fine particles (P1).

(Example 9)
In the step of obtaining the dispersion solution of the metal fine particles (P) of Example 1, the type of the compound (X) containing the Group 2 element was changed to magnesium carbonate, and the amount of the compound (X) containing the Group 2 element added was changed. The same as in Example 1 except that the magnesium concentration was changed to 500 μg / g with respect to the total amount (g) of the metal fine particles (P1).

(Example 10)
In the step of obtaining the dispersion solution of the metal fine particles (P) of Example 1, the type of the compound (X) containing the Group 2 element was changed to strontium carbonate, and the amount of the compound (X) containing the Group 2 element added was changed. The same as in Example 1 except that the strontium concentration was changed to 500 μg / g with respect to the total amount (g) of the metal fine particles (P1).

(Example 11)
In the step of obtaining the dispersion solution of the metal fine particles (P) of Example 1, the type of the compound (X) containing the Group 2 element was changed to barium carbonate, and the amount of the compound (X) containing the Group 2 element added was changed. The same as in Example 1 except that the barium concentration was changed to 500 μg / g with respect to the total amount (g) of the metal fine particles (P1).

(Example 12)
In the step of obtaining the dispersion solution of the metal fine particles (P) of Example 1, the type of the compound (X) containing the Group 2 element was changed to calcium hydroxide, and the amount of the compound (X) containing the Group 2 element added. The same as in Example 1 except that the calcium concentration was changed to 500 μg / g with respect to the total amount (g) of the metal fine particles (P1).

(Example 13)
In the step of obtaining the dispersion solution of the metal fine particles (P) of Example 1, the type of the compound (X) containing the Group 2 element was changed to calcium silicate, and the amount of the compound (X) containing the Group 2 element added. The same as in Example 1 except that the calcium concentration was changed to 500 μg / g with respect to the total amount (g) of the metal fine particles (P1).

(Example 14)
In the step of obtaining the dispersion solution of the metal fine particles (P) of Example 1, the type of the compound (X) containing the Group 2 element was changed to calcium oxalate, and the amount of the compound (X) containing the Group 2 element added. The same as in Example 1 except that the calcium concentration was changed to 500 μg / g with respect to the total amount (g) of the metal fine particles (P1).

(Comparative Example 1)
It is the same as that of Example 1 except that the compound (X) containing the Group 2 element was not added in the step of obtaining the dispersion solution of the metal fine particles (P) of Example 1.

(Comparative Example 2)
In the step of obtaining the dispersion solution of the metal fine particles (P) of Example 1, the amount of the compound (X) containing the Group 2 element added was 200 μg / g with respect to the total amount (g) of the metal fine particles (P1). It is the same as that of Example 1 except that it is changed to.

(Comparative Example 3)
In the step of obtaining the dispersion solution of the metal fine particles (P) of Example 1, the amount of the compound (X) containing the Group 2 element added was 100,000 μg / g with respect to the total amount (g) of the metal fine particles (P1). It is the same as that of Example 1 except that it is changed to.

(result)
Table 1 shows the joints of (A) the joint structure A of the aluminum member and the aluminum member, and (B) the joint structure B of the copper substrate and the aluminum member produced in each Example and each comparative example. The results of the evaluation test of the department are shown.

(Summary of results)
From the evaluation results shown in Table 1, the following can be seen.

In the step of obtaining the dispersion solution of the metal fine particles (P) of Comparative Example 1, the aluminum member and the aluminum member could not be joined due to the fact that the compound (X) containing the Group 2 element was not added. Also, it was not possible to join the aluminum member and the copper member.

In the step of obtaining the dispersion solution of the metal fine particles (P) of Comparative Example 2, the amount of calcium added to the compound (X) containing the Group 2 element is less than a predetermined range (less than 300 μg / g). However, the desired bonding strength could not be obtained at each of the joints of (A) the joint structure A between the aluminum member and the aluminum member and (B) the joint structure B between the aluminum member and the copper member.

In the step of obtaining the dispersion solution of the metal fine particles (P) of Comparative Example 3, the amount of calcium added to the compound (X) containing the Group 2 element exceeds a predetermined range (more than 80,000 μg / g). However, the desired bonding strength could not be obtained at each of the joints of (A) the joint structure A between the aluminum member and the aluminum member and (B) the joint structure B between the aluminum member and the copper member.

On the other hand, in the step of obtaining the dispersed solution of the metal fine particles (P) of Examples 1 to 14, the amount of the Group 2 element added to the compound (X) containing the Group 2 element is within a predetermined range (300). ~ 80,000 μg / g), which is desired in each of the joints of (A) the joint structure A between the aluminum member and the aluminum member and (B) the joint structure B between the aluminum member and the copper member. Bond strength was obtained.

Claims (6)

A metal joining material used to join an aluminum material to an aluminum material or a copper material.
Metal fine particles (P) containing metal fine particles (P1) having an average primary particle size in the range of 2 to 500 nm, and
An organic solvent (S) containing a divalent or higher alcohol and
Contains compound (X) containing Group 2 elements,
The weight ratio (P / S) of the metal fine particles (P) to the organic solvent (S) is in the range of 10/90 to 70/30.
The content of the divalent or higher alcohol is 20 to 100% by weight with respect to 100% by weight of the total amount of the organic solvent (S).
The content of the compound containing the Group 2 element (X) is the a 300~80000μg / g as the concentration of the second group element based on the total amount (g) of the fine metal particles (P1), a metal interconnect material .. A carbonate compound, a hydroxide salt compound, or a silicate, wherein the compound (X) containing a Group 2 element contains at least one Group 2 element among beryllium, magnesium, calcium, strontium, and barium. The material for metal bonding according to claim 1, wherein the material is at least one selected from a compound and an organic acid salt compound. The metal bonding material according to claim 2, wherein the compound (X) containing a Group 2 element is a carbonate compound containing calcium. The divalent or higher alcohol
Glycerin, 1,1,1-tris (hydroxymethyl) ethane, 1,2,4-butanetriol, 1,2,3-hexanetriol, 1,2,6-hexanetriol, and 2-ethyl-2-hydroxy At least one trihydric alcohol selected from methyl-1,3-propanediol; polyglycerin, treitol, erythritol, pentaerythritol, pentitol, 1-propanol, 2-propanol, 2-butanol, 2-methyl2-propanol, xylitol, ribitol, arabitol, hexitol, mannitol, sorbitol, zulcitol, glycerin aldehyde, dioxyacetone, triol, elittlerose, erythrose, arabinose, ribose, ribulose, xylose, xylose, Lixose, glucose, fructose, mannose, idose, sorbitol, growth, tarose, tagatous, galactose, allose, altrose, lactose, isomaltoth, glucoheptose, heptose, maltotriols, lacturose. , And at least one polyhydric alcohol selected from trehalose; the metal bonding material according to any one of claims 1 to 3, characterized in that it is at least one selected from. .. The divalent or higher alcohol
The metal bonding material according to claim 4, wherein the trihydric alcohol is glycerin; and the polyhydric alcohol is at least one selected from polyglycerin. The metal joining material according to any one of claims 1 to 5, wherein the metal used as a raw material for the metal fine particles (P1) is copper.