JP7129043B2 - Method for producing bonding copper particles, bonding paste, semiconductor device, and electric/electronic component - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing bonding copper particles, a bonding paste, and a semiconductor device and electric/electronic component manufactured using the bonding paste.

With the increase in capacity, high-speed processing, and fine wiring of semiconductor products, the problem of heat generated during the operation of semiconductor products has become conspicuous. It has become to. For this reason, a method of attaching a heat dissipating member such as a heat spreader or a heat sink to a semiconductor product is generally adopted, and a material for adhering the heat dissipating member itself is desired to have a higher thermal conductivity.
On the other hand, depending on the form of the semiconductor product, in order to make the thermal management more efficient, a method of bonding a heat spreader to the semiconductor element itself or the die pad portion of the lead frame to which the semiconductor element is bonded, and exposing the die pad portion to the package surface. A method of imparting a function as a heat sink by increasing the thickness of the heat sink (see, for example, Patent Document 1) is adopted.

Furthermore, there are cases where the semiconductor element is adhered to an organic substrate or the like having a heat dissipation mechanism such as a thermal via. Also in this case, the material for bonding the semiconductor element is required to have high thermal conductivity. In addition, due to the recent increase in brightness of white light emitting LEDs, they are also widely used in illumination devices such as backlight illumination for full-color liquid crystal screens, ceiling lights, and downlights. By the way, there is a problem that the adhesive that bonds the light emitting element and the substrate is discolored by heat and light, and the electric resistance value changes with time due to the high current input due to the high output of the light emitting element. In particular, in the method of completely relying on the adhesive strength of the adhesive to bond the light-emitting element and the substrate, the bonding material loses its adhesive strength at the melting temperature of the solder and peels off when the electronic parts are mounted by soldering. I had concerns. In addition, the higher performance of the white light emitting LED leads to an increase in the amount of heat generated by the light emitting element chip, and along with this, the structure of the LED and the members used therein are required to have improved heat dissipation properties.

In particular, in recent years, the development of power semiconductor devices using wide bandgap semiconductors such as silicon carbide (SiC) and gallium nitride, which have low power loss, has become active. High temperature operation is possible. However, in order to exhibit its properties, it is necessary to efficiently dissipate the heat generated during operation, and there is a demand for bonding materials that are excellent in long-term high-temperature heat resistance in addition to electrical conductivity and heat transfer.

As described above, materials used for bonding members of semiconductor devices and electric/electronic components (die attach pastes, heat radiating member bonding materials, etc.) are required to have high thermal conductivity. In addition, these materials also need to withstand reflow processing when the product is mounted on the board, and in many cases, bonding over a large area is required. It is also necessary to have a low stress property to suppress the

Here, in order to obtain an adhesive with high thermal conductivity, metal fillers such as silver powder and copper powder and ceramic fillers such as aluminum nitride and boron nitride are usually used as fillers in an organic binder at a high content rate. It is necessary to disperse them (see Patent Document 2, for example). However, as a result, the elastic modulus of the cured product becomes high, and it has been difficult to have both good thermal conductivity and good reflowability (that is, peeling is unlikely to occur after the reflow treatment).

Recently, however, attention has been focused on a bonding method using silver nanoparticles, which enables bonding under conditions of lower temperatures than bulk silver, as a candidate for a bonding method that can withstand such demands (for example, See Patent Document 3).
By the way, silver particles have very good conductivity, but due to their high price and migration problems, alternatives to other metals are being investigated. Therefore, at present, copper particles, which are less expensive than silver particles and have migration resistance, are attracting attention.

JP 2006-086273 A JP 2005-113059 A JP 2011-240406 A

However, bonding with copper nanoparticles requires a high temperature of 300°C to develop conductivity, and the particle size is small, making it difficult to suppress oxidation. There is Furthermore, the sintering of copper particles requires sintering in a reducing atmosphere from the viewpoint of removing the surface oxide film.

In addition, copper nanoparticles for wiring, for which research and development is particularly advanced, can be sintered at a relatively low temperature, but when used for bonding, the sintering rate and degree of sintering differ between the inside of the bonding layer and the fillet. occurred, and it was difficult to obtain a highly reliable conjugate.

The present invention has been made in view of such circumstances, and it is possible to obtain copper particles having a uniform sintering rate and a uniform sintering degree between the inside of the joining layer and the fillet portion, and having good joining properties. To provide a method for producing bonding copper particles, a bonding paste containing the bonding copper particles obtained by the manufacturing method, and a highly reliable semiconductor device and electric/electronic component by using the bonding paste. aim.

As a result of intensive studies aimed at solving the above problems, the inventors of the present invention have found that the problems can be solved by the following inventions.

That is, the present disclosure relates to the following.
[1] A method for producing copper particles for bonding, which comprises reducing (A) a copper compound with (C) a reducing compound in the presence of (B) a carboxylic acid amine salt.
[2] The method for producing bonding copper particles according to [1] above, wherein the thermal decomposition temperature of the carboxylic acid compound constituting the (B) carboxylic acid amine salt is 200° C. or lower.
[3] The method for producing bonding copper particles according to [1] or [2] above, which further comprises (D) a carboxylic acid having 1 to 12 carbon atoms.
[4] The method for producing copper particles for bonding according to [3] above, wherein the (D) carboxylic acid having 1 to 12 carbon atoms is a monocarboxylic acid.
[5] The method for producing bonding copper particles according to any one of [1] to [4], further comprising (E) an alkylamine having 1 to 12 carbon atoms.
[6] A bonding paste comprising bonding copper particles obtained by the manufacturing method according to any one of [1] to [5] above.
[7] A semiconductor device and an electrical/electronic component bonded using the bonding paste according to [6] above.

According to the present invention, the sintering rate and degree of sintering are uniform between the inside of the bonding layer and the fillet portion, and a copper particle for bonding can be obtained that has good bonding characteristics, and the manufacturing method. A bonding paste containing the bonding copper particles obtained by the method and the bonding paste can be used to provide highly reliable semiconductor devices and electrical/electronic components.

<Method for producing bonding copper particles>
The method for producing bonding copper particles of the present invention is characterized by reducing (A) a copper compound with (C) a reducing compound in the presence of (B) a carboxylic acid amine salt.

The invention will now be described in detail with reference to one embodiment.

((A) copper compound)
The (A) copper compound used in the present embodiment is not particularly limited as long as it contains a copper atom. Examples of copper compounds include copper carboxylate, copper oxide, copper hydroxide, and copper nitride. Among them, copper carboxylate is preferable from the viewpoint of uniformity during the reaction. These may be used alone or in combination of two or more.

Examples of copper carboxylates include copper formate (I), copper acetate (I), copper propionate (I), copper butyrate (I), copper valerate (I), copper caproate (I), copper caprylate (I ), copper (I) caprate, copper (II) formate, copper (II) acetate, copper (II) propionate, copper (II) butyrate, copper (II) valerate, copper (II) caproate, caprylic acid Carboxylic acid copper anhydrides or hydrates, such as copper (II), copper (II) caprate, and copper (II) citrate. Among them, copper (II) acetate monohydrate is preferable from the viewpoint of productivity and availability. Moreover, these may be used independently and may use 2 or more types together.

Moreover, a commercially available copper carboxylate may be used, or one obtained by synthesis may be used.

Carboxylic acid copper can be synthesized by a known method, for example, by mixing and heating copper(II) hydroxide and a carboxylic acid compound.

Copper oxide includes copper (II) oxide and copper (I) oxide, and copper (I) oxide is preferred from the viewpoint of productivity. Copper hydroxide includes copper (II) hydroxide and copper (I) hydroxide.
These may be used alone or in combination of two or more.

((B) carboxylic acid amine salt)
The (B) carboxylic acid amine salt used in the present embodiment is an important component in the present embodiment, and is dramatically improved in sinterability compared to a method for synthesizing copper particles composed only of an amine compound and a carboxylic acid compound. can be obtained, the sintering speed and degree of sintering between the inside of the joining layer and the fillet portion can be made uniform, and the joining characteristics can be improved. Although the reason for this is not precisely known, the authors found that the structure of the carboxylic acid amine salt relieves the strong adsorption of carboxylic acid-copper and amine compound-copper mutually, and the adsorption power to copper. This is because it is assumed that the carboxylic acid and the amine are excellent in desorption properties due to the decrease in , and as a result, good desorption behavior is exhibited even in a closed space such as the inside of the bonding layer.

(B) Carboxylic acid amine salt can be obtained from a carboxylic acid compound and an amine compound, and a commercially available one may be used, or a previously synthesized one may be used. Alternatively, the carboxylic acid compound and the amine compound may be separately charged into the reaction vessel during the production process of the copper particles to produce them in-situ.

A carboxylic acid amine salt is produced by blending a carboxylic acid compound and an amine compound in an equivalent amount of functional groups in an organic solvent and mixing them under relatively mild temperature conditions of room temperature (25°C) to about 100°C. . It is preferably taken out from the reaction liquid containing the product by a distillation method, a recrystallization method, or the like.

(B) The carboxylic acid compound constituting the carboxylic acid amine salt is not particularly limited as long as it is a compound having a carboxy group, and examples thereof include monocarboxylic acids, dicarboxylic acids, aromatic carboxylic acids, and hydroxy acids. These may be used alone or in combination of two or more. Among them, monocarboxylic acids and dicarboxylic acids are preferable from the viewpoint of reducing the difference in sintering rate between the inside of the joining layer and the fillet portion.

(B) The carboxylic acid compound constituting the carboxylic acid amine salt has a thermal decomposition temperature of preferably 200° C. or less, more preferably 190° C., from the viewpoint of reducing the difference in sintering rate between the inside of the bonding layer and the fillet portion. °C or less, and more preferably 180°C or less.

Further, among the carboxylic acid compounds constituting the carboxylic acid amine salt (B), the compound having a boiling point in a region lower than the thermal decomposition temperature is used from the viewpoint of reducing the difference in sintering rate between the inside of the bonding layer and the fillet portion. , the boiling point is preferably 280° C. or lower, more preferably 260° C. or lower, and still more preferably 240° C. or lower.

Among the carboxylic acid compounds constituting the carboxylic acid amine salt (B), monocarboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, octylic acid, nonanoic acid, capric acid, and olein. acid, stearic acid, isostearic acid and the like. These may be used alone or in combination of two or more. From the viewpoint of reducing the difference in sintering rate between the inside of the joining layer and the fillet portion, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, octylic acid, nonanoic acid, and capric acid are preferred, and valeric acid. , caproic acid, caprylic acid, nonanoic acid, and octylic acid are more preferred.

(B) Among the carboxylic acid compounds constituting the carboxylic acid amine salt, dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and diglycol. acid and the like. These may be used alone or in combination of two or more. From the viewpoint of reducing the difference in sintering rate between the inside of the joining layer and the fillet portion, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, and diglycolic acid are preferred, and oxalic acid, malonic acid, succinic acid, and diglycolic acid are preferred. Glycolic acid is more preferred.

Among the carboxylic acid compounds constituting the carboxylic acid amine salt (B), aromatic carboxylic acids include benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, and gallic acid. These may be used alone or in combination of two or more. Benzoic acid is preferable from the viewpoint of reducing the difference in sintering speed between the inside of the joining layer and the fillet portion.

(B) Among the carboxylic acid compounds constituting the carboxylic acid amine salt, hydroxy acids include glycolic acid, lactic acid, tartronic acid, malic acid, glyceric acid, hydroxybutyric acid, tartaric acid, citric acid, and isocitric acid. These may be used alone or in combination of two or more. Glycolic acid, lactic acid, and malic acid are preferable from the viewpoint of reducing the difference in sintering speed between the inside of the joining layer and the fillet portion.

(B) The amine compound constituting the carboxylic acid amine salt is not particularly limited as long as it is a compound having a carboxy group, and examples thereof include alkylmonoamines, alkyldiamines and alkanolamines. These may be used alone or in combination of two or more. From the viewpoint of sinterability, alkyl monoamines and alkanolamines are preferred.

Among the amine compounds constituting the (B) carboxylic acid amine salt, alkyl monoamines include methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, dodecylamine and the like. These may be used alone or in combination of two or more. From the viewpoint of sinterability, hexylamine, octylamine, and decylamine are preferred.

Among the amine compounds constituting the (B) carboxylic acid amine salt, alkyldiamines include 1,1-methanediamine, 1,2-ethanediamine, 1,3-propanediamine, 1,4-butanediamine, 1, 6-hexanediamine, 1,8-octanediamine and the like. These may be used alone or in combination of two or more. From the viewpoint of sinterability, 1,4-butanediamine and 1,6-hexanediamine are preferred.

Among the amine compounds constituting the (B) carboxylic acid amine salt, alkanolamines include monoethanolamine, monopropanolamine, monobutanolamine, 2-(2-aminoethylamino)ethanol, 2-(2-aminoethoxy ) ethanol, 1-amino-2-propanol, 2-amino-1-propanol, 3-amino-1,2-propanediol and the like. These may be used alone or in combination of two or more. From the viewpoint of sinterability, monoethanolamine, monopropanolamine, monobutanolamine, 1-amino-2-propanol, and 2-amino-1-propanol are preferred.

(B) The boiling point of the carboxylic acid amine salt is preferably 70° C. or higher and 280° C. or lower, more preferably 100° C. or higher and 260° C. or lower, and still more preferably 120° C. or higher and 240° C. or lower. (B) If the boiling point of the carboxylic acid amine salt is within the above range, the resulting copper particles exhibit good sinterability. If the boiling point of the carboxylic acid amine salt (B) is less than 70°C, the amine may volatilize during the heating process. It is not preferable because there is a risk of The boiling point of the carboxylic acid amine salt (B) is more preferably at least the heating temperature in the heating step and at most the sintering temperature during use.

((C) reducing compound)
The (C) reducing compound used in the present embodiment is not particularly limited as long as it has a reducing power to reduce the (A) copper compound and liberate metallic copper. Furthermore, (C) the reducing compound preferably has a boiling point of 70° C. or higher, more preferably the heating temperature in the heating step or higher. Furthermore, (C) the reducing compound is preferably a compound composed of carbon, hydrogen and oxygen and soluble in an organic solvent described later.

Such (C) reducing compounds typically include hydrazine derivatives. Examples of hydrazine derivatives include hydrazine monohydrate, methylhydrazine, ethylhydrazine, n-propylhydrazine, i-propylhydrazine, n-butylhydrazine, i-butylhydrazine, sec-butylhydrazine, t-butylhydrazine, n -pentylhydrazine, i-pentylhydrazine, neo-pentylhydrazine, t-pentylhydrazine, n-hexylhydrazine, i-hexylhydrazine, n-heptylhydrazine, n-octylhydrazine, n-nonylhydrazine, n-decylhydrazine, n -undecylhydrazine, n-dodecylhydrazine, cyclohexylhydrazine, phenylhydrazine, 4-methylphenylhydrazine, benzylhydrazine, 2-phenylethylhydrazine, 2-hydrazinoethanol, acetohydrazine and the like. These may be used alone or in combination of two or more.

((D) carboxylic acid having 1 to 12 carbon atoms)
It is preferable that (D) a carboxylic acid having 1 to 12 carbon atoms is further included in the method for producing bonding copper particles of the present embodiment. (D) A carboxylic acid having 1 to 12 carbon atoms is used for the purpose of controlling the particle size of the resulting copper particles. Carboxylic acid is not particularly limited as long as it has a carboxyl group. For example, monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, octylic acid, nonanoic acid, capric acid, oleic acid, stearic acid, isostearic acid; oxalic acid, malonic acid, succinic acid acids, dicarboxylic acids such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and diglycolic acid; aromatic carboxylic acids such as benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, and gallic acid hydroxy acids such as glycolic acid, lactic acid, tartronic acid, malic acid, glyceric acid, hydroxybutyric acid, tartaric acid, citric acid and isocitric acid; Among them, a monocarboxylic acid having 1 to 12 carbon atoms is preferable from the viewpoint of reducing the difference in sintering rate between the inside of the joining layer and the fillet portion. From the viewpoint of ease of particle size control, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, octylic acid, nonanoic acid, capric acid, oleic acid, stearic acid, isostearic acid, oxalic acid , malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and diglycolic acid are preferable, and from the viewpoint of sinterability, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, Caproic acid, caprylic acid, octylic acid, oxalic acid, malonic acid and succinic acid are more preferred, and caproic acid, caprylic acid, octylic acid, oxalic acid and malonic acid are more preferred.

((E) alkylamine having 1 to 12 carbon atoms)
It is preferable that (E) an alkylamine having 1 to 12 carbon atoms is further included in the method for producing bonding copper particles of the present embodiment.
(E) Alkylamine having 1 to 12 carbon atoms is used for the purpose of controlling the particle size of the resulting copper particles. The alkylamine is not particularly limited as long as it has an amino group. For example, methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, dodecylamine, 1,1-methanediamine, 1,2-ethanediamine, 1,3-propanediamine, 1,4-butanediamine , 1,6-hexanediamine, 1,8-octanediamine, monoethanolamine, monopropanolamine, monobutanolamine, 2-(2-aminoethylamino)ethanol, 2-(2-aminoethoxy)ethanol, 1- Amino-2-propanol, 2-amino-1-propanol, 3-amino-1,2-propanediol and the like can be mentioned. From the viewpoint of ease of particle size control, methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, dodecylamine, monoethanolamine, monopropanolamine, monobutanolamine, 2-(2-aminoethyl Amino)ethanol, 2-(2-aminoethoxy)ethanol, 1-amino-2-propanol, 2-amino-1-propanol, and 3-amino-1,2-propanediol are preferred, and from the viewpoint of sinterability, Hexylamine, octylamine, monoethanolamine, monopropanolamine, monobutanolamine, 1-amino-2-propanol, 2-amino-1-propanol are preferred.

(Organic solvent)
The (A) copper compound, (B) the carboxylic acid amine salt, and (C) the reducing compound may be mixed in an organic solvent.
The organic solvent is not particularly limited as long as it can be used as a reaction solvent that does not impair the properties of the complex or the like produced from the mixture obtained by mixing the raw materials described above. Among them, alcohols exhibiting compatibility with the reducing compound (C) are preferably used.

Further, since the reduction reaction of copper ions by (C) the reducing compound is an exothermic reaction, it is more preferable to use an organic solvent that does not volatilize during the reduction reaction. If the organic solvent evaporates, it becomes difficult to control the formation of copper ions due to the decomposition of the copper compound-carboxylic acid amine salt complex and the precipitation of metallic copper due to the reduction of the formed copper ions, and the stability of the particle size may deteriorate. I don't like it. Therefore, the organic solvent preferably has a boiling point of 70° C. or higher and is composed of carbon, hydrogen and oxygen.

Examples of the alcohols used as organic solvents include 1-propanol, 2-propanol, butanol, pentanol, hexanol, heptanol, octanol, ethylene glycol, 1,3-propanediol, 1,2-propanediol, butyl carbitol, Butyl carbitol acetate, ethyl carbitol, ethyl carbitol acetate, diethylene glycol diethyl ether, butyl cellosolve and the like. These may be used alone or in combination of two or more.

(A) the copper compound described above, (B) the amine salt of carboxylic acid, (C) the reducing compound, (D) a carboxylic acid having 1 to 12 carbon atoms, which is added as necessary, and (E) 1 carbon atom. Using an alkylamine of ∼12 and an organic solvent, copper particles can be produced as follows.

(formation of mixture)
First, an organic solvent is placed in a reaction vessel, and (A) a copper compound, (B) a carboxylic acid amine salt, (C) a reducing compound, and, if necessary, (D) are added in the organic solvent. A carboxylic acid having 1 to 12 carbon atoms and (E) an alkylamine having 1 to 12 carbon atoms are mixed. The order of mixing these compounds is not particularly limited, and the above compounds may be mixed in any order.

In order to efficiently form a complex of (A) a copper compound and (B) a carboxylic acid amine salt, the (A) copper compound and (B) a carboxylic acid amine salt are mixed first, and the Mix for about 5 to 30 minutes at 110° C., then add (C) reducing compound, (D) carboxylic acid having 1 to 12 carbon atoms, and (E) alkylamine having 1 to 12 carbon atoms and mix. is preferred.

In the above mixing, the amount of (A) copper compound, (B) carboxylic acid amine salt, and (C) reducing compound used is 0.1 to 10 mol of (B) carboxylic acid amine salt per 1 mol of (A) copper compound. , (C) 0.5 to 5 mol of the reducing compound is preferable, (B) 1 to 5 mol of the carboxylic acid amine salt, and (C) 0.5 to 3 mol of the reducing compound are more preferable.
The amount of the (D) carboxylic acid having 1 to 12 carbon atoms to be used is preferably 0.5 to 5 mol, more preferably 0.5 to 3 mol, per 1 mol of the copper compound (A). The amount of (E) alkylamine having 1 to 12 carbon atoms to be used is preferably 0.5 to 5 mol, more preferably 0.5 to 3 mol, per 1 mol of (A) copper compound.
The organic solvent may be used in an amount that allows the above components to sufficiently react, and for example, about 50 to 2000 mL may be used.

(heating of the mixture)
Next, the mixture obtained by the above mixing is sufficiently heated to advance the reduction reaction of (A) the copper compound. By this heating, unreacted (A) copper compound can be eliminated, and metallic copper can be favorably deposited and grown to form copper particles.

At this time, (B) the amine salt of carboxylic acid adheres to the surface of the copper particles and suppresses the growth of the particles, thereby preventing the particles from becoming coarse.

The heating temperature in the heating of the mixture is a temperature at which the (A) copper compound is thermally decomposed and reduced to generate copper particles, for example, it is preferably 70 to 150 ° C., and may be 80 to 120 ° C. more preferred. Furthermore, the heating temperature is preferably lower than the boiling points of the components (A) to (E) and the organic solvent. When the heating temperature is within the above range, the copper particles can be efficiently generated, and when a carboxylic acid and/or an alkylamine are used in combination with (B) the carboxylic acid amine salt, volatilization of these is suppressed. preferable.

On the other hand, if the heating temperature is less than 70° C., quantitative thermal decomposition of the copper compound (A) is difficult to occur, and undecomposed copper compounds may remain. On the other hand, if the heating temperature exceeds 150° C., the volatilization amount of (B) the amine salt of carboxylic acid becomes too large, and the system becomes non-uniform, which is not preferable.

The precipitated solid matter may be separated from excess (B) carboxylic acid amine salt by centrifugation or the like, washed with an organic solvent, and dried under reduced pressure. Copper particles can be obtained by such an operation.

(shape and size of copper particles)
In the copper particles obtained by the method for producing copper particles for bonding of the present embodiment, (A) the copper compound is reduced by (C) the reducing compound in the (B) carboxylic acid amine salt, and the eluted copper atoms are aggregated. , nucleation, nucleus growth, and (B) copper particles coated with carboxylic acid amine salt are assumed to be formed. Therefore, by appropriately selecting the type of (A) copper compound, (B) carboxylic acid amine salt, and (C) reducing compound to be used, and the reaction temperature, the supply rate of copper atoms, or (B) carboxylic acid amine salt can be changed to obtain copper particles of any shape and size.

The copper particles obtained by the method for producing bonding copper particles of the present embodiment can be fired at a low temperature of less than 300 ° C., and the bonding paste using this can achieve a sintering rate between the inside of the bonding layer and the fillet portion and It is possible to obtain a bonding layer with high bonding reliability with no difference in the degree of sintering.

The average particle size of the copper particles is preferably 1 to 1000 nm, more preferably 20 to 800 nm, and still more preferably 30 to 500 nm, from the viewpoint of denseness of the bonding layer.
Incidentally, the average particle size of the copper particles, 10 copper particles (n = Calculated as the average value of 10). The average value is an arithmetic average value, and 10 or more copper particles may be used for the calculation.

<Joining paste>
The bonding paste of the present embodiment contains bonding copper particles obtained by the method for manufacturing bonding copper particles described above. Therefore, the bonding paste of the present embodiment can be bonded without pressure and has excellent adhesiveness. It is suitable as a die attach paste for element bonding or a material for bonding heat dissipating members, since a cured product with good sufficiency can be obtained.

The bonding paste of the present embodiment preferably uses two or more copper particles having different average particle sizes together. For example, the average particle size of the second copper particles having a larger average particle size than the first copper particles is preferably about 2 to 10 times the average particle size of the first copper particles. Also, the amount of the second copper particles is preferably about 1.5 to 10 times the amount of the first copper particles.

The bonding paste of the present embodiment preferably contains, in addition to the above-described copper particles, large-particle-size copper particles having a particle size larger than that of the above-described copper particles, a thermosetting resin, an organic solvent, and other additives. This makes it possible to reduce the influence of sintering shrinkage of the copper particles and form a bonding layer with higher reliability.

(Large particle size copper particles)
The large-diameter copper particles preferably have an average particle size of more than 1 μm and 30 μm or less, more preferably 2 to 20 μm. The shape is not particularly limited, and spherical, plate-like, flake-like, scale-like, dendritic, rod-like, wire-like and the like can be used.
The average particle size of the large-diameter copper particles can be measured using a laser diffraction/scattering particle size distribution analyzer or the like.

The large-diameter copper particles may be treated with lubricants and antirust agents. A typical such treatment is treatment with a carboxylic acid compound. Examples of carboxylic acid compounds include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, octylic acid, nonanoic acid, capric acid, palmitic acid, oleic acid, stearic acid, isostearic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, diglycolic acid, benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, gallic acid, glycolic acid, lactic acid, tartronic acid, malic acid, glyceric acid, hydroxybutyric acid, tartaric acid, citric acid, isocitric acid and the like. From the viewpoint of sinterability with copper particles, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, octylic acid, nonanoic acid, capric acid, palmitic acid, oleic acid, stearic acid, isostearic acid, Oxalic acid, malonic acid, succinic acid and glutaric acid are preferred, and caproic acid, caprylic acid, octylic acid, nonanoic acid, capric acid, malonic acid, succinic acid and glutaric acid are preferred from the viewpoint of dispersibility and oxidation resistance of copper particles. is more preferred.

(Thermosetting resin)
The thermosetting resin is not particularly limited as long as it is a thermosetting resin that is generally used as an adhesive. Among them, liquid resins are preferable, and resins that are liquid at room temperature (25° C.) are more preferable. Examples of the thermosetting resin include cyanate resin, epoxy resin, radically polymerizable acrylic resin, and maleimide resin. These may be used alone or in combination of two or more.
By including a thermosetting resin in the bonding paste of the present embodiment, an adhesive material (paste) having an appropriate viscosity can be obtained. Moreover, when the bonding paste of the present embodiment contains a thermosetting resin, the temperature of the bonding paste rises due to the heat of reaction during curing, which is also preferable because it has the effect of promoting the sinterability of the copper particles.

A cyanate resin is a compound having an —NCO group in the molecule, and is a resin that forms a three-dimensional network structure and cures when the —NCO group reacts with heating. Specific examples include 1,3-dicyanatobenzene, 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, 1,3-dicyanatonaphthalene, 1,4-dicyanatonaphthalene, 1, 6-dicyanatonaphthalene, 1,8-dicyanatonaphthalene, 2,6-dicyanatonaphthalene, 2,7-dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 4,4′-dicyanatobiphenyl, bis (4-cyanatophenyl)methane, bis(3,5-dimethyl-4-cyanatophenyl)methane, 2,2-bis(4-cyanatophenyl)propane, 2,2-bis(3,5-dibromo -4-cyanatophenyl)propane, bis(4-cyanatophenyl)ether, bis(4-cyanatophenyl)thioether, bis(4-cyanatophenyl)sulfone, tris(4-cyanatophenyl)phosphite, Tris(4-cyanatophenyl) phosphate, and cyanates obtained by reacting a novolac resin with cyanogen halide, and the like. Prepolymers having triazine rings formed by trimerizing the cyanate groups of these polyfunctional cyanate resins can also be used. The prepolymer is obtained by polymerizing the above-described polyfunctional cyanate resin monomer using, for example, an acid such as mineral acid or Lewis acid, a base such as sodium alcoholate or tertiary amines, or a salt such as sodium carbonate as a catalyst. can get.

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

An epoxy resin is a compound having one or more glycidyl groups in the molecule, and is a resin that forms a three-dimensional network structure and cures by reacting the glycidyl groups with heating. It is preferable that two or more glycidyl groups are contained in one molecule. This is because a compound containing only one glycidyl group cannot exhibit sufficient cured product properties even if reacted. A compound containing two or more glycidyl groups in one molecule can be obtained by epoxidizing a compound having two or more hydroxyl groups. Examples of such compounds include bisphenol compounds such as bisphenol A, bisphenol F and biphenol, derivatives thereof, hydrogenated bisphenol A, hydrogenated bisphenol F, hydrogenated biphenol, cyclohexanediol, cyclohexanedimethanol, and cyclohexanediethanol. bifunctional epoxidized diols having a structure or derivatives thereof, aliphatic diols such as butanediol, hexanediol, octanediol, nonanediol, decanediol, or derivatives thereof, trihydroxyphenylmethane skeleton, aminophenol Examples include trifunctional ones obtained by epoxidizing compounds having a skeleton, and polyfunctional ones obtained by epoxidizing phenol novolac resins, cresol novolak resins, phenol aralkyl resins, biphenyl aralkyl resins, naphthol aralkyl resins, etc. These include It is not limited. In addition, since the above-mentioned epoxy resin is paste-like as a bonding paste at room temperature (25° C.), it is preferable that it is liquid at room temperature (25° C.) alone or as a mixture. It is also possible to use reactive diluents as is customary. Examples of reactive diluents include monofunctional aromatic glycidyl ethers such as phenyl glycidyl ether and cresyl glycidyl ether, and aliphatic glycidyl ethers.

At this time, a curing agent is used for the purpose of curing the epoxy resin. Examples of curing agents for epoxy resins include aliphatic amines, aromatic amines, dicyandiamides, dihydrazide compounds, acid anhydrides, and phenolic resins. . Dihydrazide compounds include carboxylic acid dihydrazide such as adipic acid dihydrazide, dodecanoic acid dihydrazide, isophthalic acid dihydrazide, and p-oxybenzoic acid dihydrazide. Examples include phthalic anhydride, endomethylenetetrahydrophthalic anhydride, dodecenylsuccinic anhydride, a reaction product of maleic anhydride and polybutadiene, and a copolymer of maleic anhydride and styrene.

Furthermore, a curing accelerator can be blended to accelerate curing, and curing accelerators for epoxy resins include imidazoles, triphenylphosphine or tetraphenylphosphine and salts thereof, amine compounds such as diazabicycloundecene, and Its salts and the like can be mentioned. For example, 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethyl Imidazole compounds such as imidazole, 2-C ₁₁ H ₂₃ -imidazole, adducts of 2-methylimidazole and 2,4-diamino-6-vinyltriazine are preferably used. Of these, imidazole compounds having a melting point of 180° C. or higher are particularly preferred.

A radically polymerizable acrylic resin is a compound having a (meth)acryloyl group in the molecule, and is a resin that forms a three-dimensional network structure and cures by reacting the (meth)acryloyl group. It is preferable that one or more (meth)acryloyl groups are contained in the molecule.

Here, examples of acrylic resins include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 1,2-cyclohexanediol mono(meth)acrylate, 1,3-cyclohexanediol mono(meth)acrylate, 1,4-cyclohexanediol mono(meth)acrylate, 1,2-cyclohexanedimethanol mono(meth)acrylate, 1,3-cyclohexanedimethanol mono(meth)acrylate, 1,4-cyclohexanedimethanol mono(meth)acrylate, 1,2-cyclohexanediethanol mono(meth)acrylate , 1,3-cyclohexanediethanol mono(meth)acrylate, 1,4-cyclohexanediethanol mono(meth)acrylate, glycerin mono(meth)acrylate, glycerin di(meth)acrylate, trimethylolpropane mono(meth)acrylate, trimethylol (Meth)acrylates having a hydroxyl group such as propanedi(meth)acrylate, pentaerythritol mono(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, neopentyl glycol mono(meth)acrylate, and these) A (meth)acrylate having a carboxyl group obtained by reacting a (meth)acrylate having a hydroxyl group with a dicarboxylic acid or a derivative thereof may be used. Dicarboxylic acids which can be used here include, for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, tetrahydrophthalic acid. , hexahydrophthalic acid and derivatives thereof.

Further, particularly preferred acrylic resins include polyethers, polyesters, polycarbonates, poly(meth)acrylates having a molecular weight of 100 to 10000 and having (meth)acrylic groups, hydroxyl group-containing (meth)acrylates, and hydroxyl group-containing compounds. (meth)acrylamide, and the like.

A maleimide resin is a compound containing one or more maleimide groups in one molecule, and is a resin that forms a three-dimensional network structure and cures by reacting the maleimide groups with heating. For example, N,N'-(4,4'-diphenylmethane)bismaleimide, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, 2,2-bis[4-(4-maleimidophenoxy)phenyl ] and bismaleimide resins such as propane. More preferred maleimide resins are compounds obtained by reaction of diamine dimer acid and maleic anhydride, and compounds obtained by reaction of maleimidated amino acids such as maleimidoacetic acid and maleimidocaproic acid with polyols. The maleimidated amino acid is obtained by reacting maleic anhydride with aminoacetic acid or aminocaproic acid, and the polyol is preferably polyether polyol, polyester polyol, polycarbonate polyol, or poly(meth)acrylate polyol. Those not containing are particularly preferred.

Here, when the thermosetting resin is blended, it is blended in an amount of 1 to 20 parts by mass when the total amount of the copper particles and large-diameter copper particles is 100 parts by mass. When the thermosetting resin is 1 part by mass or more, a sufficient adhesive effect can be obtained by the thermosetting resin. , high thermal conductivity can be sufficiently ensured, and heat dissipation can be improved. Also, the organic component is not excessively increased, and deterioration due to light and heat can be suppressed. As a result, the life of the light-emitting device can be extended. By using such a blending range, the adhesion performance of the thermosetting resin is used to prevent contact between the copper particles and/or the large-sized copper particles, and the mechanical strength of the entire adhesive layer is maintained. can be easily done.

(Organic solvent)
A known solvent can be used as the organic solvent as long as it functions as a reducing agent.
Alcohol is preferable as the organic solvent, and examples thereof include aliphatic polyhydric alcohols. Examples of aliphatic polyhydric alcohols include glycols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, glycerin and polyethylene glycol. These organic solvents may be used alone or in combination of two or more.

By using alcohol as an organic solvent, the heat treatment at the time of paste curing (sintering) increases the reducing power of the alcohol by increasing the temperature, and the copper oxide partially present in the copper particles and on the metal substrate It is believed that the metal oxide (for example, copper oxide) is reduced by the alcohol to become a pure metal, and as a result, a cured film that is denser, has higher conductivity, and has higher adhesion to the substrate can be formed. In addition, since the alcohol is sandwiched between the semiconductor element and the metal substrate, part of the alcohol is in a reflux state during the heat treatment for curing the paste, and the alcohol, which is a solvent, does not immediately disappear from the system due to volatilization. At curing temperatures, the metal oxides become more efficiently reduced.

Specifically, the boiling point of the organic solvent is 100 to 300°C, preferably 150 to 290°C. When the boiling point is 100° C. or higher, the volatility does not become too high even at room temperature, and a reduction in reducing ability due to volatilization of the dispersion medium can be suppressed, and stable adhesive strength can be obtained. Moreover, when the boiling point is 300° C. or lower, the cured film (conductive film) is likely to be sintered, and a highly dense film can be formed. In addition, it is possible to prevent the organic solvent from volatilizing and remaining in the film.

When an organic solvent is blended, the blending amount is preferably 7 to 20 parts by mass based on 100 parts by mass of copper particles. When it is 7 parts by mass or more, the viscosity does not become too high and workability can be improved, and when it is 20 parts by mass or less, viscosity reduction is suppressed, copper sinking in the paste is suppressed, and reliability is improved. be able to.

In the bonding paste of the present embodiment, in addition to the above components, a curing accelerator, rubber, silicone, etc., which are generally blended in this type of composition, to the extent that the effects of the present invention are not impaired. Agents, coupling agents, antifoaming agents, surfactants, colorants (pigments, dyes), various polymerization inhibitors, antioxidants, solvents, and other various additives can be blended as necessary. Each of these additives may be used alone or in combination of two or more.

The bonding paste of the present embodiment is prepared by sufficiently mixing the above-described copper particles, large-diameter copper particles that are blended as necessary, thermosetting resins, organic solvents, additives such as coupling agents, etc. , Further kneading treatment using a disperse, a kneader, a three-roll mill, etc., followed by defoaming.

The viscosity of the bonding paste of the present embodiment is, for example, preferably 20 to 300 Pa·s, more preferably 40 to 200 Pa·s.
The bonding strength of the bonding paste of the present embodiment is preferably 25 MPa or more, more preferably 30 MPa or more.
The above viscosity and bonding strength can be measured by the methods described in Examples.

The bonding paste of the present embodiment thus obtained is excellent in high thermal conductivity and heat dissipation. Therefore, when it is used as a bonding material for elements or heat-dissipating members to substrates or the like, it improves the dissipation of heat from the inside of the device to the outside, making it possible to stabilize product characteristics.

<Semiconductor devices and electrical/electronic components>
The semiconductor device and electric/electronic component of the present embodiment are excellent in reliability because they are bonded using the bonding paste described above.

The semiconductor device of this embodiment uses the bonding paste described above to bond a semiconductor element onto a substrate that serves as an element supporting member. That is, here, the bonding paste is used as a die attach paste, and the semiconductor element and the substrate are bonded and fixed via this paste.

Here, the semiconductor element may be any known semiconductor element, such as a transistor and a diode. Further, the semiconductor element includes a light emitting element such as an LED. In addition, the type of the light-emitting device is not particularly limited, and examples include those in which a nitride semiconductor such as InN, AlN, GaN, InGaN, AlGaN, InGaAlN, etc. is formed as a light-emitting layer on a substrate by the MOBVC method or the like. be done.
Further, the element support member includes a support member made of a material such as copper, copper-plated copper, PPF (pre-plating lead frame), glass epoxy, ceramics, or the like.

By using the bonding paste of the present embodiment, it is possible to bond even base materials that have not been metal-plated. The semiconductor device obtained in this way has dramatically improved connection reliability against temperature cycles after mounting compared with the conventional one. In addition, since the electric resistance value is sufficiently small and changes little over time, there is an advantage that even when driven for a long time, the decrease in output over time is small and the life is long.

Further, the electric/electronic component of the present embodiment is formed by bonding a heat radiating member to a heat generating member using the bonding paste. That is, the bonding paste is used here as a material for bonding the heat radiating member, and the heat radiating member and the heat generating member are bonded and fixed via the bonding paste.

The heat-generating member may be the above-described semiconductor element or a member having the semiconductor element, or may be another heat-generating member. Examples of heat-generating members other than semiconductor elements include optical pickups and power transistors. Moreover, a heat sink, a heat spreader, etc. are mentioned as a thermal radiation member.

In this way, by bonding the heat-generating member to the heat-generating member using the bonding paste, the heat generated by the heat-generating member can be efficiently released to the outside by the heat-generating member, and the temperature rise of the heat-generating member can be suppressed. be able to. The heat-generating member and the heat-dissipating member may be directly adhered via a bonding paste, or may be indirectly adhered with another member having high thermal conductivity interposed therebetween.

EXAMPLES Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

(Preparation of carboxylic acid amine salt)
[Preparation Example 1]
40 mmol of nonanoic acid (manufactured by Tokyo Chemical Industry Co., Ltd., trade name: nonanoic acid) and 40 mmol of hexylamine (manufactured by Tokyo Chemical Industry Co., Ltd., trade name: hexylamine) were placed in a 50 mL sample bottle, and an aluminum block type Heat was generated up to 60°C when the mixture was stirred and mixed in a heating stirrer. Subsequently, the mixture was stirred and mixed at 60°C for 15 minutes and cooled to room temperature (25°C) to obtain hexylamine nonanoate (yield: 10.3 g, yield: 99.2%).

[Preparation Example 2]
Succinic acid (manufactured by Tokyo Chemical Industry Co., Ltd., trade name: succinic acid) 20 mmol and DL-1-amino-2-propanol (manufactured by Tokyo Chemical Industry Co., Ltd., trade name: DL-1-amino-2-propanol) ) was placed in a 50 mL sample bottle and stirred and mixed in an aluminum block heating stirrer, generating heat up to 70°C. The mixture was continuously stirred and mixed at 70° C. for 15 minutes and cooled to room temperature (25° C.) to obtain succinic acid aminopropanol salt (yield 5.0 g, yield 99.9%).

(Production of copper particles)
[Synthesis Example 1]
(A) 20 mmol of copper (II) acetate monohydrate (manufactured by Tokyo Kasei Kogyo Co., Ltd., trade name: copper (II) acetate monohydrate) as a copper compound, and (B) a preparation example of a carboxylic acid amine salt 40 mmol of the nonanoic acid hexylamine salt obtained in 1 and 3 mL of butyl cellosolve (manufactured by Tokyo Kasei Kogyo Co., Ltd.) as an organic solvent were placed in a 50 mL sample bottle and mixed at 90° C. for 5 minutes in an aluminum block heating stirrer. , as a copper precursor solution. After cooling the copper precursor solution to room temperature (25° C.), 3 mL of 1-propanol was added to (C) hydrazine monohydrate as a reducing compound (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd., trade name: hydrazine monohydrate). hydrate) was added to the copper precursor solution in the sample bottle and stirred for 5 minutes.

The mixture was again heated and stirred at 90° C. with an aluminum block type heating stirrer for 2 hours. After 5 minutes, 2 mL of ethanol (manufactured by Kanto Kagaku Co., Ltd., special grade) was added, and a solid was obtained by centrifugation (4000 rpm (1 minute)). The centrifugally separated solid was dried under reduced pressure to obtain powdery copper particles 1 (average particle size: 50 nm, yield: 0.31 g, yield: 97.8%) with copper luster.

[Synthesis Example 2]
Copper (II) acetate monohydrate was replaced with cuprous oxide (manufactured by Furukawa Chemicals Co., Ltd., trade name: FRC-10A), and nonanoic acid hexylamine salt was replaced with succinic acid aminopropanol salt obtained in Preparation Example 2. Except for this, synthesis was carried out in the same manner as in Synthesis Example 1 to obtain powdery copper particles 2 having a copper luster (average particle diameter: 300 nm, yield: 0.2 g, yield: 97.6%).

[Synthesis Example 3]
(A) 20 mmol of copper (II) acetate monohydrate (manufactured by Tokyo Kasei Kogyo Co., Ltd., trade name: copper (II) acetate monohydrate) as a copper compound, and (B) a preparation example of a carboxylic acid amine salt 40 mmol of the nonanoic acid hexylamine salt obtained in 1 and 3 mL of butyl cellosolve (manufactured by Tokyo Kasei Kogyo Co., Ltd.) as an organic solvent were placed in a 50 mL sample bottle and mixed at 90° C. for 5 minutes in an aluminum block heating stirrer. After that, (D) 20 mmol of caproic acid (manufactured by Tokyo Chemical Industry Co., Ltd., trade name: hexanoic acid) as a carboxylic acid having 1 to 12 carbon atoms was added, and further mixed at 90 ° C. for 5 minutes to obtain a copper precursor solution. did. After cooling the copper precursor solution to room temperature (25° C.), 3 mL of 1-propanol was added to (C) hydrazine monohydrate as a reducing compound (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd., trade name: hydrazine monohydrate). hydrate) was added to the copper precursor solution in the sample bottle and stirred for 5 minutes.

The mixture was again heated and stirred at 90° C. with an aluminum block type heating stirrer for 2 hours. After 5 minutes, 2 mL of ethanol (manufactured by Kanto Kagaku Co., Ltd., special grade) was added, and a solid was obtained by centrifugation (4000 rpm (1 minute)). The centrifugally separated solid was dried under reduced pressure to obtain powdery copper particles 3 having copper luster (average particle diameter: 40 nm, yield: 0.30 g, yield: 94.3%).

[Synthesis Example 4]
Synthesis was carried out in the same manner as in Synthesis Example 3, except that 20 mmol of octylamine (manufactured by Tokyo Chemical Industry Co., Ltd., trade name: n-octylamine) was used as (E) an alkylamine having 1 to 12 carbon atoms in place of caproic acid. Thus, powdery copper particles 4 (average particle size: 100 nm, yield: 0.29 g, yield: 91.2%) with copper luster were obtained.

[Synthesis Example 5]
Synthesis was carried out in the same manner as in Synthesis Example 3 except that no hexylamine nonanoic acid salt was used, and powdery copper particles 5 with copper luster (average particle diameter 150 nm, yield 0.30 g, yield 94.3%) were obtained. Obtained.

[Synthesis Example 6]
Synthesis was carried out in the same manner as in Synthesis Example 4 except that no hexylamine nonanoic acid salt was used, and powdery copper particles 6 with copper luster (average particle diameter 180 nm, yield 0.29 g, yield 91.2%) were obtained. Obtained.

The average particle size of the copper particles obtained in each synthesis example is based on the observation image of a scanning electron microscope (manufactured by JEOL Ltd., trade name: JSM-7600F; SEM). It was calculated as the average value of particles (n=10).

Table 1 shows the components used in Synthesis Examples 1-6. In addition, in Table 1, a blank represents no compounding.

(Examples 1 to 4 and Comparative Examples 1 and 2)
Each component of the type and compounding amount shown in Table 2 was mixed and kneaded with a roll to obtain a bonding paste. In addition, in Table 2, a blank represents no compounding.

The details of each component listed in Table 2 used in the preparation of the bonding paste are as follows.
(copper particles)
Copper particles 1: Copper particles obtained in Synthesis example 1 Copper particles 2: Copper particles obtained in Synthesis example 2 Copper particles 3: Copper particles obtained in Synthesis example 3 Copper particles 4: Synthesis example 4 Copper particles/copper particles 5 obtained in Synthesis Example 5: Copper particles/copper particles 6: Copper particles obtained in Synthesis Example 6 (organic solvent)
・Diethylene glycol: manufactured by Tokyo Chemical Industry Co., Ltd.

Using the bonding paste obtained in each example and comparative example, evaluation was performed by the following methods. Table 2 shows the results.
<Method for evaluating bonding paste>
[viscosity]
The value at 25°C and 5 rpm was measured using an E-type viscometer (3° cone).

[Pot life]
The number of days until the viscosity increased by 0.7 times or more the initial viscosity when the bonding paste was left in a constant temperature bath at 25° C. was measured.

[Sinterability (coating film)]
The bonding paste was applied to a glass substrate (thickness 1 mm) by a screen printing method so as to have a thickness of 25 μm, and was cured at 200° C. for 60 minutes. The electric resistance of the obtained sintered film was measured by the four-probe method using Loresta GP (trade name, manufactured by Mitsubishi Chemical Analytic Co., Ltd.).
A value of 1.0×10 ⁻⁴ Ω·m or less was rated as ◯, and a value of more than 1.0×10 ⁻⁴ Ω·m was rated as ×.

<Evaluation Method of Semiconductor Device>
[Joint strength]
A silicon chip with a gold vapor deposition layer on the bonding surface of 2 mm × 2 mm was mounted on a solid copper frame and PPF (Ni-Pd/Au-plated copper frame) using bonding paste, and nitrogen (3% hydrogen). It was cured at 200° C. for 60 minutes in an atmosphere. After curing and after moisture absorption treatment (85°C, 85% relative humidity, 72 hours), the die shear strength at room temperature (25°C) was measured using DAGE 4000Plus (product name, manufactured by Nordson KK).

[Cold and heat shock resistance]
A silicon chip having a 2 mm×2 mm bonding surface provided with a deposited gold layer was mounted on a copper frame and PPF using a bonding paste, and cured at 200° C. for 60 minutes in a nitrogen (3% hydrogen) atmosphere. Using an epoxy sealing material (trade name: KE-G3000D) manufactured by Kyocera Corporation, a package molded under the following conditions was subjected to moisture absorption treatment at 85° C. and relative humidity of 85% for 168 hours, followed by IR reflow treatment ( 260 ° C., 10 seconds) and thermal cycle treatment (one cycle is an operation of increasing the temperature from -55 ° C. to 150 ° C. and cooling to -55 ° C., and this is 1000 cycles). The number of internal cracks generated was observed with an ultrasonic microscope.
Note that Table 2 shows the number of samples in which cracks occurred for five samples.

(Molding condition)
Package: 80pQFP (14mm x 20mm x 2mm thickness)
Chip: backside gold-plated silicon chip Lead frame: PPF and copper Molding of encapsulant: 175°C, 2 minutes Post-mold cure: 175°C, 8 hours

From the above results, the method for producing bonding copper particles of the present invention contains a carboxylic acid amine salt as an essential component, so that the obtained bonding paste containing copper particles has a high degree of sintering in both the coating state and the bonding state. sex is obtained. On the other hand, as shown in the comparative examples, when the carboxylic acid amine salt was not contained, although high sinterability was exhibited in the coating state, sinterability was poor in the bonded state.
Moreover, it was found that the bonding paste containing the copper particles obtained by the method for producing the bonding copper particles of the present invention can obtain high bonding reliability. Therefore, by using the bonding paste, a highly reliable semiconductor device and electrical/electronic equipment can be obtained.

Claims (8)

(A) a copper compound, (B) a pre-synthesized carboxylic acid amine salt, and (C) a reducing compound are mixed,
A method for producing copper particles for bonding, wherein the (A) copper compound is reduced with the (C) reducing compound in the presence of the (B) previously synthesized carboxylic acid amine salt. 2. The method for producing bonding copper particles according to claim 1, wherein the thermal decomposition temperature of the carboxylic acid compound constituting the (B) previously synthesized carboxylic acid amine salt is 200[deg.] C. or lower. 3. The method for producing bonding copper particles according to claim 1, further comprising (D) a carboxylic acid having 1 to 12 carbon atoms. 4. The method for producing copper particles for bonding according to claim 3, wherein the (D) carboxylic acid having 1 to 12 carbon atoms is a monocarboxylic acid. 5. The method for producing bonding copper particles according to any one of claims 1 to 4, further comprising (E) an alkylamine having 1 to 12 carbon atoms. (A) a copper compound, (B) a pre-synthesized carboxylic acid amine salt, and (C) a reducing compound are mixed,
A bonding paste comprising bonding copper particles obtained by reducing the (A) copper compound with the (C) reducing compound in the presence of the (B) previously synthesized carboxylic acid amine salt. . A semiconductor device in which a semiconductor element and a substrate are bonded with a cured product of the bonding paste according to claim 6 . An electric/electronic component comprising a heat-radiating member and a heat-generating member bonded together with the cured bonding paste according to claim 6 .