KR20130109150A - Electrically conductive copper particles, process for producing electrically conductive copper particles, composition for forming electrically conductive body, and base having electrically conductive body attached thereto - Google Patents

Abstract

This invention relates to electroconductive copper particle which contains 50-1000 mass ppm of chlorine atoms with respect to the gross mass of particle | grains, and the chlorine atom exists in water-insoluble form.

Description

TECHNICAL CONDUCTIVE COPPER PARTICLES, PROCESS FOR PRODUCING ELECTRICALLY CONDUCTIVE COPPER PARTICLES, COMPOSITION FOR FORMING ELECTRICALLY CONDUCTIVE BODY, AND BASE HAVING ELECTRICAL THERETO}

The present invention relates to a conductive copper particle and a method for producing the conductive copper particle, a composition for forming a conductor, and a substrate on which a conductor is formed.

As a manufacturing method of the base material with a conductor film which has a conductor film of a desired wiring pattern, such as a printed circuit board, the method of apply | coating silver paste containing silver particle on a desired wiring pattern on a base material, and hardening is known. However, silver conductor films are likely to cause short circuits due to ion migration. Therefore, in view of the reliability of electronic devices, forming a conductor film using copper paste instead of silver paste has been studied. However, copper particles tend to be oxidized, and an oxide film is easily formed on the surface. Therefore, the volume resistivity of the conductor film using copper particle | grains tends to become high, and the change with time is large.

As a manufacturing method of the electroconductive copper particle which forms the conductor film with low volume resistivity, the following methods (1)-(3) are known.

(1) The method of processing the electrically conductive powder which consists of copper or a copper alloy with the aqueous solution containing an acid, a reducing agent, and the alkali metal salt of a C8 or more fatty acid (patent document 1).

(2) A method of adding hypophosphoric acid to an aqueous copper salt solution to precipitate copper hydride fine particles, thermally decomposing the copper hydride fine particles to obtain copper fine particles (Patent Document 2).

(3) Copper particle which contained 0.05 mol or more (1250 mass ppm or more) of chloride ions with respect to the copper ion, and reduced it to pH 10-12.5 in the solution containing copper ion, and provided the surface with a bumpy unevenness | corrugation. The method of manufacturing (patent document 3).

Japanese Unexamined Patent Publication No. 2007-184143 Japanese Patent Laid-Open No. 2-294417 Japanese Unexamined Patent Publication No. 2007-169770

However, although the conductor film using the copper particle manufactured by the method (1) has the outstanding electroconductivity immediately after film-forming, since the volume resistivity increases significantly by room temperature and air storage, it cannot be used for the wiring of an electronic device.

According to the method (2), particles in which copper hydride fine particles are aggregated can be obtained, but when the conductive film is used using the particles produced by this method, the conductivity is insufficient, and the volume resistivity increases due to storage at room temperature and in the air. .

Since the conductor film using the copper particle manufactured by the method (3) has a large volume resistivity even after film formation, and its volume resistivity increases with time, it cannot be used for the wiring of an electronic device.

The present invention provides a method for producing conductive copper particles and conductive copper particles capable of forming a conductor film having a low volume resistivity and a small change over time, a composition for forming a conductor containing the conductive copper particles, and the conductor An object of the present invention is to provide a substrate on which a conductor having a conductor film formed by the composition for formation is formed.

The electroconductive copper particle of this invention contains 50-1000 mass ppm of chlorine atoms with respect to the gross mass of particle | grains, and the chlorine atom exists in water-insoluble form.

It is preferable that the electroconductive copper particle of this invention is 0.01-20 micrometers in average particle diameter.

The composition for conductor formation of this invention contains the electroconductive copper particle of this invention, and a solvent. Moreover, it is preferable that the composition for conductor formation of this invention contains a resin binder.

The substrate on which the conductor of the present invention is formed has a conductor film formed on the substrate by the substrate and the composition for forming a conductor of the present invention.

The manufacturing method of the electroconductive copper particle of this invention is a method which has the process of reducing at least one of copper particle and copper (II) ion in the reaction system which contains chloride ion, pH 3 or less, and redox potential is 220 kPa or less. .

By using the electroconductive copper particle of this invention, a conductor film with a low volume resistivity and a small change with time can be formed.

Moreover, according to the manufacturing method of the electroconductive copper particle of this invention, the electroconductive copper particle which can form the conductor film with low volume resistivity and small change with time is obtained.

Moreover, the composition for conductor formation of this invention contains the electroconductive copper particle of this invention, and can form the conductor film | membrane with low volume resistivity and small change with time.

In addition, the substrate on which the conductor of the present invention is formed has a low volume resistivity of the conductor film and a small change with time.

<Conductive Copper Particles>

By using the electroconductive copper particle of this invention, a conductor film with a low volume resistivity and a small increase in volume resistivity with time can be formed. The reason why the conductor film having the above effect can be formed is not necessarily clear, but is estimated as follows.

The electroconductive copper particle of this invention contains the chlorine atom which exists in water-insoluble form. In this specification, that a chlorine atom exists in water-insoluble form means that the chloride ion concentration measured by the measuring method mentioned later will be 10 mass ppm or less.

In order to obtain the electroconductive copper particle of this invention, although copper (II) ion (bivalent copper ion) is reduced, in the process, it is thought to pass via copper (I) ion (monovalent copper ion). When copper (I) ions are produced, if an appropriate amount of chloride ions, which are monovalent anions, are present in the vicinity, both react quickly and are considered to form copper chloride (I) on the surface of the conductive copper particles. Therefore, it is thought that oxidation of the surface of electroconductive copper particle is suppressed and a low volume resistivity is obtained. Further, copper chloride (I) has a very low solubility in water and a low affinity with water, so that deterioration due to moisture in the air is small. Therefore, even if it is set as the base material in which a conductor was formed, it is thought that the outstanding effect which can suppress the increase of a volume resistivity for a long time is considered.

As mentioned above, in the electroconductive copper particle of this invention, it is thought that a chlorine atom exists in the form with very low solubility to water. However, since identification of copper chloride (I) in electroconductive copper particle is difficult, it is defined that it is water-insoluble because the chloride ion concentration measured by the measuring method mentioned later becomes 10 mass ppm or less.

Content of the chlorine atom in electroconductive copper particle is 50-1000 mass ppm with respect to the gross mass of electroconductive copper particle, and 80-300 mass ppm is preferable. If content of a chlorine atom is more than the said lower limit, advancing of surface oxidation of a copper particle can be suppressed. If content of a chlorine atom is below the said upper limit, the conductor film with a small volume resistivity can be formed. Content of the chlorine atom in electroconductive copper particle is measured by fluorescent X-ray analysis.

(Measurement)

1. Content of the chlorine atom in electroconductive copper particle is measured by the fluorescent X-ray analysis method.

2. If all chlorine atoms contained in the conductive copper particles are eluted in distilled water, the conductive copper particles in an amount such that the concentration of chloride ions contained in the distilled water is 100 mass ppm are immersed in distilled water.

3. After distilled water in which electroconductive copper particle was immersed was stirred at 1000 rpm for 5 second using the test tube mixer (made by As One, HM-01) at 20 degreeC, the chloride ion concentration eluted in the distilled water is measured. . Here, distilled water used is distilled water which adjusted the dissolved oxygen concentration to 1 mass ppm or less.

Further, the dissolved oxygen concentration of 1 ppm by mass or less means that copper chloride (I) (monovalent copper) present in the conductive copper particles is affected by oxidation by dissolved oxygen (II) (divalent copper). This is to prevent the change.

0.5 or less is preferable and, as for the surface oxygen amount represented by the ratio of the surface oxygen concentration (unit: atomic%) with respect to the surface copper concentration (unit: atomic%) of electroconductive copper particle, 0.3 or less is more preferable. If the said surface oxygen amount is below the said upper limit, the contact resistance between electroconductive copper particle will become smaller, and the electroconductivity of a conductor film will improve.

In addition, the surface oxygen concentration and surface copper concentration of electroconductive copper particle are calculated | required by X-ray photoelectron spectroscopy. Measurements are taken over a range from the particle surface up to about 3 nm deep towards the center. If the measurement is made in this range, the state of a particle surface can fully be grasped | ascertained.

The form of the electroconductive copper particle of this invention is not specifically limited. Examples of the conductive copper particles of the present invention include the following conductive copper particles (A) to (E).

(A) Copper particles which contain the chlorine atom of a water-insoluble form, and whose average particle diameter is 1 micrometer or more.

(B) Primary particles containing chlorine atoms of water-insoluble form, the average particle diameter of which is 20 to 2 as secondary particles containing chlorine atoms of water-insoluble form, on the surface of copper particle whose average particle diameter is 1 micrometer or more. Copper composite particle with 350 nm copper hydride microparticles | fine-particles adhered.

(C) Copper hydride microparticles | fine-particles which are the secondary particle containing the chlorine atom of a water-insoluble form, and whose average particle diameter is 10 nm-1 micrometer.

(D) Primary particles containing a chlorine atom in the non-aqueous form, the average particle diameter of 20 ~ as secondary particles containing a chlorine atom in the non-aqueous form, on the surface of the copper particles having an average particle diameter of 1 µm or more. Copper composite particle with 350 micrometers copper fine particle affixed.

(E) Copper microparticles | fine-particles which contain the chlorine atom of a water-insoluble form, and whose average particle diameter is 10 nm-1 micrometer.

Electroconductive copper particle (B) and electroconductive copper particle (D) are electroconductive copper particle which consists of a combination of a primary particle and a secondary particle, electroconductive copper particle (A), (C), and (E) are only primary particles, Or electroconductive copper particles composed of only secondary particles.

Copper hydride microparticles | fine-particles are converted into metallic copper by heating, and copper hydride microparticles | fine-particles turn into copper microparticles | fine-particles. That is, electroconductive copper particle (B) turns into electroconductive copper particle (D) by heating. In addition, electroconductive copper particle (C) turns into electroconductive copper particle (E) by heating.

It is preferable that the electroconductive copper particle of this invention is coat | covered with the organic substance for the purpose of the fluidity improvement of the composition for antioxidant prevention and conductor formation. In addition, "coating" includes not only the case where the organic substance has covered the whole surface of electroconductive copper particle, but also the case where it partially covers. Furthermore, not only the case where an organic substance is bonded to the surface of electroconductive copper particle, but the case where it is coordinated, etc. are included.

As said organic substance, a carboxylic acid, an amine, an imidazole compound, a triazole compound, etc. are mentioned.

Examples of the carboxylic acid include oleic acid, stearic acid, myristic acid, dodecanoic acid, decanoic acid, octylic acid, octanoic acid, hexanoic acid, benzoic acid, salicylic acid, and abietic acid.

Examples of the amines include oleylamine, stearylamine, myristylamine, dodecylamine, decylamine, octylamine, hexylamine, aniline, and the like.

As said organic substance, when preparing the composition for conductor formation containing a resin binder with electroconductive copper particle, carboxylic acid is preferable from a viewpoint of the wettability of the said electroconductive copper particle and resin, and oleic acid, salicylic acid, and abiete acid More preferred. In addition, wettability is the affinity of the particle | grain surface and resin by changing interface energy.

As for the average particle diameter of the electroconductive copper particle of this invention, 0.01-20 micrometers is preferable, and what is necessary is just to adjust suitably in this range according to the shape of electroconductive copper particle. As for the average particle diameter in case an electroconductive copper particle contains a primary particle, 1-10 micrometers is more preferable. Moreover, 0.01-1 micrometer is preferable and, as for the average particle diameter in case an electroconductive copper particle consists only of secondary particles, 0.02-0.4 micrometer is especially preferable. When the average particle diameter of electroconductive copper particle is more than the said lower limit, the fluid flow characteristic of the composition for conductor formation containing this electroconductive copper particle will become favorable. If the average particle diameter of electroconductive copper particle is below the said upper limit, it will become easy to manufacture a fine wiring.

The average particle diameter in this specification can be calculated | required as follows according to the shape of electroconductive copper particle. When obtaining an average primary particle diameter with respect to a primary particle, it calculates by measuring the particle diameter of 100 particle | grains randomly selected from the scanning electron microscope (henceforth "SEM") image, and averaging those particle diameters. About secondary particles, it calculates by measuring the particle diameter of 100 particle | grains randomly selected from the transmission electron microscope (henceforth "TEM") image, and averaging those particle diameters.

When a copper particle is not spherical, if it is a primary particle, the average value of the long diameter and short diameter of a copper particle shall be made into a particle diameter. When particle | grains are secondary particle | grains, let the average value of the long diameter of a secondary particle and the short diameter of a secondary particle be a particle diameter.

In addition, in the case of electroconductive copper particle (B), the whole electroconductive copper particle (B) containing the copper particle which is a primary particle and the copper hydride microparticles | fine-particles which are secondary particle | grains adhered to this copper particle is observed by SEM, and 2 The average value of the long diameter and the short diameter including the difference particles is used as the particle diameter. Similarly, in the case of electroconductive copper particle (D), the whole electroconductive copper particle (D) containing the copper particle which is a primary particle, and the copper microparticles | fine-particles which are the secondary particle adhered to this copper particle is observed by SEM, and it is secondary The average value of the long diameter and the short diameter including particle | grains is made into particle diameter.

<Method for producing conductive copper particles>

The electroconductive copper particle of this invention is manufactured by the manufacturing method which has the process of reducing at least one of copper particle and copper (II) ion in the reaction system which contains chloride ion, pH 3 or less, and redox potential is 220 kPa or less. can do. Hereinafter, the specific manufacturing method is demonstrated for every kind of form of the electroconductive copper particle to manufacture.

(Method for producing conductive copper particle (A))

As a method of manufacturing electroconductive copper particle (A), the method of having the following process ((alpha) -1) and ((alpha) -2) is mentioned, for example.

(α-1) A reaction system having copper particles (hereinafter referred to as "copper particles (a1)") as primary particles dispersed in a dispersion medium, containing chloride ions, having a pH of 3 or less and a redox potential of 220 kPa or less ( Hereinafter, the process of reducing copper particle (a1) in "reaction system ((alpha))" and obtaining electroconductive copper particle (A).

(α-2) A step of separating the conductive copper particles (A) from the reaction system (α).

Process (α-1):

The copper particles (a1) are dispersed in a dispersion medium, a compound dissolved in the dispersion medium to generate chloride ions is added, a reducing agent is added at a pH of 3 or less, and a reaction system (α) is formed to form the copper particles (a1). Reduce. Here, during a reduction reaction, it adjusts so that the oxidation-reduction potential of reaction system (alpha) may be 220 kPa or less. The surface of copper particles (a1) is oxidized normally, and the oxide film which consists of a cuprous oxide is formed. In the reaction system (α) of the step (α-1), the cuprous oxide of the oxide film of the copper particles (a1) is reduced. Moreover, after adding the compound which melt | dissolves in a dispersion medium and produces | generates chloride ion, and adds a reducing agent to pH 3 or less, you may disperse | distribute copper particle (a1) and form reaction system ((alpha)). Here too, during the reduction reaction, the redox potential of the reaction system (α) is adjusted to be 220 kPa or less.

As copper particle (a1), the well-known metal copper particle generally used for the composition for conductor formation called a copper paste is mentioned. This metallic copper particle is a primary particle. In addition, spherical shape may be sufficient as the particle shape of a copper particle (a1), and shapes, such as plate shape and phosphorus shape, may be sufficient as it.

Since copper particles are easy to oxidize the surface, commercially available copper particles are often surface treated with long chain carboxylic acids such as stearic acid, oleic acid and myristic acid for the purpose of preventing oxidation of the surface. Since the copper particle surface-treated with long-chain carboxylic acid is hydrophobic, it is easy to aggregate in high polar dispersion media, such as water mentioned later. Therefore, when using the copper particle surface-treated with long chain carboxylic acid, it is preferable to remove long chain carboxylic acid of a surface before a process ((alpha-1)). Removal of long-chain carboxylic acid of a surface can be performed by treating copper particle with a degreasing agent or heat-processing in alkaline aqueous solution.

In addition, as mentioned later, the medium of copper particle (a1) uses a medium with high polarity, such as a mixed medium of water, water, and alcohols. From the viewpoint of the dispersibility of the copper particles (a1) to these high polar dispersion mediums being improved and the aggregation of the copper particles easily suppressed, the copper particles pretreated with a dispersant are preferred as the copper particles (a1). The dispersant is supported on the surface of the copper particles to hydrophilize the surface. Even if it is the copper particle surface-treated with long chain carboxylic acid, the copper particle which the surface became hydrophilic is obtained by pretreatment with a dispersing agent.

As the dispersant, various water-soluble compounds having chemical adsorption to copper particles can be used. As said water-soluble compound, a short chain aliphatic carboxylic acid, a water-soluble high molecular compound, a chelating agent, etc. are mentioned.

As short-chain aliphatic carboxylic acid, Aliphatic monocarboxylic acids, such as C6 or less aliphatic monocarboxylic acid, aliphatic hydroxy monocarboxylic acid, aliphatic amino acid; Aliphatic polycarboxylic acids, such as C10 or less aliphatic polycarboxylic acid and aliphatic hydroxy polycarboxylic acid, are more preferable.

Examples of the water-soluble high molecular compound include polyvinyl alcohol, polyacrylic acid, polyvinylpyrrolidone, hydroxypropyl cellulose, propyl cellulose and ethyl cellulose.

Ethylenediaminetetraacetic acid, iminodi diacetic acid, etc. are mentioned as a chelating agent.

As the dispersant, short-chain aliphatic carboxylic acids are preferable, and aliphatic polycarboxylic acids having 8 or less carbon atoms, such as glycine, alanine, citric acid, citric anhydride, malic acid, maleic acid and malonic acid, are more preferable. Aliphatic dicarboxylic acids, such as these, or tricarboxylic acids, such as a citric acid, are especially preferable.

Pretreatment can be performed by dissolving a dispersing agent in solvents, such as water, and adding and stirring a copper particle in this solution. Thereby, a dispersing agent couple | bonds with the copper particle surface. It is preferable to perform pretreatment by replacing the inside of a process container with an inert gas from a viewpoint of suppressing oxidation of the surface of a copper particle. Nitrogen gas, argon gas, etc. can be used as an inert gas. After the pretreatment, the solvent is removed and, if necessary, washed with water or the like, thereby obtaining copper particles whose surface is hydrophilic by the pretreatment.

Pretreatment can be performed even under heating. By carrying out the pretreatment under heating, the treatment rate is improved. The heating temperature is preferably 50 ° C. or higher, or lower than the boiling point of a solvent such as water (in the case of using a low boiling point dispersant). The heating time is preferably 5 minutes or more. In addition, since heating for a long time is not economical, the heating time is preferably 3 hours or less.

As for the quantity of the dispersing agent used for pretreatment, 0.1-10 mass parts is preferable with respect to 100 mass parts of copper particles before pretreatment.

As for the average particle diameter (average primary particle diameter) of a copper particle (a1), 1-20 micrometers is preferable. Thereby, the electroconductive copper particle (A) whose average particle diameter (average primary particle diameter) is 1-20 micrometers is easy to be obtained.

As for the density | concentration of the copper particle (a1) in reaction system ((alpha)) (100 mass%), 0.1-50 mass% is preferable. When the concentration of the copper particles (a1) is 0.1% by mass or more, the amount of dispersion medium used can be suppressed, and the production efficiency of the conductive copper particles (A) becomes good. When the density | concentration of a copper particle (a1) is 50 mass% or less, since the influence of aggregation of copper particle (a1) becomes smaller, the yield of electroconductive copper particle (A) tends to become high.

As a dispersion medium, the medium containing water or water as a main component and containing alcohols, such as methanol, ethanol, 2-propanol, ethylene glycol, can be used, Water is especially preferable. In addition, having water as a main component means that water is 70 mass% or more in 100 mass% of dispersion mediums.

5-100 mass ppm is preferable with respect to the gross mass of the reaction system (alpha), and, as for the density | concentration of the chloride ion in a reaction system ((alpha)), 10-50 mass ppm is more preferable. When the concentration of chloride ions is equal to or greater than the lower limit, since an appropriate amount of chloride ions are present on the surface of the copper particles (a1) in the course of the reduction reaction, copper chloride (I) is likely to be formed, and the conductive copper particles having low volume resistivity (A) is easy to be obtained. Moreover, when the density | concentration of chloride ion is below the said upper limit, it is easy to suppress that electroconductivity falls that there is too much quantity of copper chloride (I) in electroconductive copper particle (A).

The concentration of chloride ions can be adjusted by adjusting the amount of the compound dissolved in the dispersion medium of the copper particles (a1) to produce chloride ions. As a compound which produces chloride ion, hydrochloric acid, sodium chloride, potassium chloride, copper (II) chloride, etc. can be used suitably.

PH of reaction system ((alpha)) is 3 or less, 0.5-3 are preferable and 0.5-2 are more preferable. When the pH of the reaction system (α) is 3 or less, reduction of the oxide film on the surface of the copper particles (a1) is performed smoothly. In addition, it is known that a stable region of copper chloride (I) exists at a specific redox potential in a region of low pH below pH 3 (Nakano Hiroaki et al., Journal of MMIJ, 123 (2007), 33-). P. 38). From this, in the step (α-1), when the oxide film is reduced, copper chloride (I) is formed on the surface of the copper particles (a1), and as a result, conductive copper particles containing chlorine atoms in a non-aqueous form ( It is thought that A) is obtained.

Moreover, when pH is 0.5 or more, it is easy to restrain excessive elution of copper (II) ion from a copper particle, and it is easy to carry out surface modification of a copper particle (a1) smoothly.

PH of reaction system (alpha) is adjusted with a pH adjuster.

An acid can be used as a pH adjuster. As the acid of the pH adjuster, carboxylic acid soluble in water or alcohols such as formic acid, citric acid, maleic acid, malonic acid, acetic acid and propionic acid is preferable. The said carboxylic acid may adsorb | suck to the copper particle surface, and may remain on the surface of the electroconductive copper particle (A) after a reduction process. The said carboxylic acid which remain | survives can expect the effect which protects the surface of electroconductive copper particle (A), and suppresses oxidation. As an acid of a pH adjuster, formic acid is especially preferable among the said carboxylic acid. Formic acid is a compound having the structure (-CHO) of an aldehyde, and thus has reducing properties. Therefore, by formic acid remaining on the surface of the conductive copper particles (A) after the reduction treatment, the effect of suppressing oxidation of the surface of the conductive copper particles (A) becomes higher, and as a result, a conductor using the conductive copper particles (A) It is easy to suppress the increase in the volume resistivity of the film.

As an acid of a pH adjuster, you may use sulfuric acid, nitric acid, hydrochloric acid, etc. other than the carboxylic acid soluble in the said water or alcohols. Hydrochloric acid can simultaneously adjust the concentration of chloride ions and adjust the pH. When pH of the dispersion liquid which disperse | distributed a copper particle (a1) to the dispersion medium, and added the compound (hydrochloric acid etc.) which produces a chloride ion is 3 or less, this dispersion liquid can be used for a reduction process as it is.

In addition, when pH becomes too low by acid, pH can be adjusted using a base as a pH adjuster.

The redox potential (ORP) of the reaction system (α) is 220 kV or less, preferably 150-220 kV, particularly preferably 180-220 kV. When ORP is 220 Pa or less, the reducing effect of the oxide film on the surface of copper particle (a1) becomes large, and surface modification fully advances. If the ORP is more than 220 GPa, the surface modification becomes insufficient, not only the initial volume resistivity is large, but also the time-dependent change in the volume resistivity becomes large. In this specification, ORP is calculated | required as a potential difference with respect to the electric potential of a standard hydrogen electrode (SHE).

ORP of the reaction system (α) can be adjusted according to the kind of reducing agent used. Moreover, it can adjust to some extent with acid which has reducing property, such as formic acid.

Examples of the reducing agent include hypophosphorous acid compounds, amineborane compounds, and hydrides.

Examples of the hypophosphorous acid compound include hypophosphorous acid and hypophosphite.

Dimethylamine borane etc. are mentioned as an amine borane compound.

Examples of the hydride include boron hydride salts.

As a reducing agent, hypophosphoric acid, hypophosphite, dimethylamine borane, or a borohydride salt is preferable, and hypophosphoric acid or hypophosphite is especially preferable.

1 mol or more is preferable with respect to the whole copper particle (a1), and, as for the usage-amount of a reducing agent, 1.2-10 mol is more preferable. When the usage-amount of a reducing agent is 1 mol or more with respect to the whole copper particle (a1), a reducing agent will become large excess with respect to copper on the copper particle (a1) surface, and reduction will fully advance. If the amount of the reducing agent is 10 moles or less based on the entire copper particles (a1), it is economically advantageous and the amount of the reducing agent decomposition product decreases, so that the removal thereof becomes easy.

The reduction reaction may be initiated by dispersing the copper particles (a1) in a dispersion medium, adding a reducing agent to a dispersion liquid in which the concentration and pH of chloride ions are adjusted, adjusting the concentration and pH of chloride ions, and adding copper to the dispersion medium in which the reducing agent is added. You may start by disperse | distributing particle | grains (a1).

5-60 degreeC is preferable and, as for the reaction temperature of a reduction reaction, 35-50 degreeC is more preferable. If reaction temperature is below the said lower limit, reduction reaction will advance easily. If reaction temperature is below the said upper limit, the influence of the concentration change of the reaction system ((alpha)) by evaporation of a dispersion medium is small.

After completion | finish of a reduction reaction, the obtained electroconductive copper particle (A) is isolate | separated from the reaction system ((alpha)), wash | cleaned with water etc. as needed, and it dries to obtain the powder of electroconductive copper particle (A). Since by-products, such as a reducing agent decomposition product, are soluble in a dispersion medium, it can isolate | separate from electroconductive copper particle (A) by methods, such as filtration and centrifugation.

(Method for producing conductive copper particle (B))

As a method of manufacturing electroconductive copper particle (B), the method of having the following process ((beta) -1)-a process ((beta) -3) is mentioned, for example.

(β-1) Cu (II) ions are reduced in a reaction system containing copper (II) ions and chloride ions and having a pH of 3 or less and an ORP of 220 Pa or less (hereinafter referred to as "reaction system (β)"), The process of producing | generating copper hydride microparticles | fine-particles (henceforth "copper hydride microparticles | fine-particles (b1)") of the average particle diameter of 20-350 nm as a secondary particle.

(β-2) Copper particles which are primary particles (hereinafter referred to as "copper particles (b2)") are added to the reaction system (β) before, during or after production of the copper hydride fine particles (b1), and copper A process of producing a copper hydride composite particle (electroconductive copper particle (B)) in which the copper hydride microparticles | fine-particles (b1) adhered to the surface of particle | grains (b2).

(β-3) A step of separating the conductive copper particles (B) from the reaction system (β).

Process (β-1):

A water-soluble copper compound is dissolved in a solvent, a compound dissolved in the solvent to generate chloride ions is added, and a reducing agent having a pH of 3 or less and a redox potential of 220 kPa or less is added to form a reaction system β. do. In the reaction system (β), copper (II) ions are reduced by the reducing agent to produce copper hydride fine particles (b1) which are secondary particles containing chlorine atoms in the non-aqueous form. It is preferable to make copper hydride microparticles | fine-particles (b1) into the aggregated secondary particle of 20-350 nm.

As a water-soluble copper compound, copper sulfate (II), copper nitrate (II), copper formate (II), copper acetate (II), copper chloride (II), copper bromide (II), copper iodide (I), etc. are mentioned. .

The solvent is not particularly limited as long as the water-soluble copper compound is dissolved and is inert to the reducing agent described later. Water or a mixed solvent of water and alcohols (ethanol, isopropyl alcohol, etc.) is preferable, and water is particularly preferable. Do.

As for the density | concentration of the water-soluble copper compound in reaction system ((beta)) (100 mass%), 0.1-30 mass% is preferable. When the concentration of the water-soluble copper compound is 0.1% by mass or more, the amount of the solvent used can be suppressed, and the production efficiency of the copper hydride fine particles (b1) becomes good. The yield of copper hydride microparticles | fine-particles (b1) improves that the density | concentration of water-soluble copper compound is 30 mass% or less.

5-100 mass ppm is preferable with respect to the gross mass of reaction system (beta), and, as for the density | concentration of chloride ion in a reaction system ((beta)), 10-50 mass ppm is more preferable. The concentration of chloride ions can be adjusted by using a compound that is dissolved in the dispersion medium to produce chloride ions. As a compound which produces chloride ion, hydrochloric acid, sodium chloride, potassium chloride, copper (II) chloride, etc. can be used suitably.

PH of reaction system (beta) shall be 3 or less. When pH of reaction system (beta) is 3 or less, copper (II) ion and hydrogen ion in reaction system (beta) are reduced by a reducing agent, and copper hydride microparticles | fine-particles (b1) are fully produced | generated. Moreover, it is thought that copper chloride (I) is produced from copper (I) ion and chloride ion by which copper (II) ion was reduced, and copper hydride particle (b1) containing a chlorine atom in a water-insoluble form is produced. As for pH of reaction system ((beta)), 0.5-2 are more preferable from a viewpoint of the production efficiency of copper hydride microparticles | fine-particles (b1).

As an acid which adjusts pH of a reaction system ((beta)), the thing similar to what was illustrated by description of the said electroconductive copper particle (A) manufacture is mentioned, The effect which suppresses the oxidation of the surface of the obtained electroconductive copper particle (B) becomes higher, Formic acid is particularly preferable from the viewpoint of easily increasing the volume resistivity of the conductor film.

The oxidation-reduction potential (ORP) of the reaction system (β) is preferably 220 Pa or less and preferably 150 to 220 Pa. When ORP is 220 Pa or less, the reduction effect of copper (II) ion becomes large, and copper hydride microparticles | fine-particles (b1) are fully produced | generated. If the ORP is more than 220 GPa, the surface modification becomes insufficient, not only the initial volume resistivity is large, but also the time-dependent change in the volume resistivity becomes large.

Examples of the reducing agent include the same as those exemplified in the description of the production of the conductive copper particles (A). Hypophosphoric acid, hypophosphite, dimethylamine borane, or borohydride salts are preferable, and hypophosphoric acid or hypophosphite is particularly preferred. desirable.

As for the addition amount of a reducing agent, 1.2-10 times mole is preferable with respect to the water-soluble copper compound to be used. If the amount of the reducing agent added is 1.2 times or more based on the water-soluble copper compound, the reduction reaction proceeds smoothly. When the amount of the reducing agent added is 10 times or less with respect to the water-soluble copper compound, it is easy to suppress the amount of impurities (sodium, boron, phosphorus, etc.) contained in the copper hydride fine particles (b2).

The reaction system (β) may be formed by mixing a reducing agent solution in which a reducing agent is dissolved in a solvent such as water and a solution in which a water-soluble copper compound is dissolved in a solvent such as water (hereinafter referred to as a "water-soluble copper compound solution"), You may add and form the solid reducing agent of this in water-soluble copper compound solution.

Reaction system ((beta)) means the system in which copper hydride microparticles | fine-particles produce | generate, Specifically, it contains copper (II) ion and chloride ion, and after adding a reducing agent to the water-soluble copper compound solution of pH 3 or less, copper hydride is still The production | generation reaction of copper hydride microparticles | fine-particles (b1) complete | finishes the system in which the production | generation reaction of the fine particle (b1) is not advanced, the system of the state in which the production | generation reaction of copper hydride microparticles (b1) is advanced, and the produced | generated copper hydride microparticles ( b1) means a system in a dispersed state. In the reaction system (β), a solvent of a water-soluble copper compound solution, a water-soluble copper compound (substantially ionized and present as copper (II) ions, a pair of anions, etc.) dissolved in the solvent, and a compound that generates chloride ions (Substantially ionized and present as chloride ions, pair cations, etc.), ions and residues after the copper hydride fine particles (b1) are produced, and the like, and decomposed products thereof.

For example, when the produced copper hydride microparticles (b1) are isolated and newly dispersed in a dispersion medium to form a dispersion, the copper hydride microparticles (b1) in the dispersion are composed of the copper hydride microparticles (b1) present in the reaction system (β). no.

60 degreeC or less is preferable, as for the reaction temperature of a reaction system ((beta)), 5-60 degreeC is more preferable, 20-50 degreeC is especially preferable. Copper hydride has the property of decomposing by heating, but when the reaction temperature of the reaction system (β) is equal to or less than the above upper limit, decomposition of the copper hydride fine particles (b2) is easily suppressed. If the reaction temperature of reaction system ((beta)) is more than the said lower limit, reduction reaction will advance easily.

Process (β-2):

Copper hydride composite particles in which copper particles (b2) that are primary particles are added to the reaction system (β) formed in step (β-1), and copper hydride fine particles (b1) are attached to the surface of copper particles (b2). Electroconductive copper particle (B) is produced | generated. The copper particles (b2) added in the step (β-2) have a surface oxide film reduced in the reaction system (β), contain chlorine atoms in a non-aqueous form, and hydrogenation containing a water-insoluble chlorine atom on the surface. Copper particle (b1) adheres.

The addition time of the copper particle (b2) to the reaction system (β) is before the production of the copper hydride fine particles (b1), during the production of the copper hydride fine particles (b1) or after the production of the copper hydride fine particles (b1). Adding the copper particles (b2) to the reaction system (β) before generation of the copper hydride fine particles (b1) means that the copper particles (b2) already exist at the time when the reaction system (β) is formed. For example, after adding a copper particle (b2) in a water-soluble copper compound solution, the case where a reaction system ((beta)) is formed by adding a reducing agent is mentioned. In addition, adding copper particle (b2) to the reaction system (beta) after production | generation of copper hydride microparticles | fine-particles (b1) is a state in which the new generation of copper hydride microparticles | fine-particles (b1) has not generate | occur | produced, and is already produced It means adding copper particle (b2) to the reaction system ((beta)) of the state in which the further growth of (b1) does not generate | occur | produce. For example, the case where copper particle (b2) is added after copper ion and a reducing agent in a reaction system (beta) are consumed and generation | generation reaction of copper hydride microparticles | fine-particles (b1) do not occur is mentioned.

The addition of the copper particles (b2) to the reaction system (β) is carried out before the production of the copper hydride fine particles (b1) or the generation of the copper hydride fine particles (b1) from the viewpoint of easily obtaining the conductive copper particles (B) having a low volume resistivity. Medium way is preferable. Copper (II) ions exist in the reaction system (β) before and during the production of the copper hydride fine particles (b1). By adding the copper particles (b2) in the state where the copper (II) ions are present in the reaction system (β), the copper (II) ions can be reduced in the state where the copper particles (b2) and the copper hydride fine particles (b1) coexist. Since it can be, copper particle | grains (b2) and copper hydride microparticles | fine-particles (b1) are combined more firmly. Presence of copper (II) ion can be grasped | ascertained by the method of measuring the copper atom concentration by the spectral spectrum analysis of an ultraviolet-ion electrode, ultraviolet-visible light, and atomic emission spectrum.

As copper particle (b2) added to a reaction system ((beta)), the copper particle similar to the copper particle (a1) demonstrated by manufacture of the said electroconductive copper particle (A) is mentioned, and an average particle diameter (average primary particle diameter) is 1-20. Preference is given to copper particles having a thickness of m.

Content of copper particle (b2) in reaction system ((beta)) is content with respect to 100 mass parts of content of copper (II) ion in the water-soluble copper compound solution before adding a reducing agent (all water-soluble copper compounds shall be ionized). 1-100 mass parts is preferable, and 5-100 mass parts is more preferable.

Process (β-3):

The produced electroconductive copper particle (B) is isolate | separated from reaction system ((beta)), and powder particle | grains are obtained. The method of separating an electroconductive copper particle (B) is not specifically limited, For example, centrifugation, filtration, etc. are mentioned.

The separated conductive copper particles (B) are preferably washed with a cleaning solution such as water to remove soluble impurities adhering to the conductive copper particles (B). In addition, you may remove the solvent of the reaction system (beta), and the impurity (anion of a water-soluble copper compound, the decomposition product of a reducing agent, etc.) which are melt | dissolved in this solvent before solvent isolation | separation before separation.

(Method for Producing Conductive Copper Particles (C))

As a method of manufacturing electroconductive copper particle (C), the method of having the following process ((gamma) -1) and ((gamma) -2) is mentioned, for example.

(γ-1) A copper (II) ion is reduced in a reaction system containing copper (II) ions and chloride ions, having a pH of 3 or less and an ORP of 220 Pa or less (hereinafter referred to as "reaction system (γ)"), It is a secondary particle and the process of producing | generating copper hydride microparticles | fine-particles (electroconductive copper particle (C)) whose average particle diameter is 10 nm-1 micrometer.

(γ-2) A step of separating the conductive copper particles (C) from the reaction system (γ).

Process (γ-1):

The step (γ-1) can be carried out by the same method as the step (β-1) in the production of the conductive copper particles (B) except for the following preferable conditions.

As for the average particle diameter of the secondary particle of the electroconductive copper particle (C) produced by the reaction system ((gamma)), 10 nm-1 micrometer are preferable. The average particle diameter of electroconductive copper particle (C) can be adjusted by control of reaction temperature, reaction time, and addition of a dispersing agent.

Process (γ-2):

Process ((gamma) -2) can be performed similarly to process ((beta) -3) in manufacture of electroconductive copper particle (B).

(Method for producing conductive copper particle (D))

As a method of manufacturing electroconductive copper particle (D), electroconductive copper particle (B) is manufactured, the obtained electroconductive copper particle (B) is heated, and the copper hydride microparticles | fine-particles (b1) in electroconductive copper particle (B) are metal-ized. The method of converting into a copper fine particle and making it into electroconductive copper particle (D) is mentioned.

In this case, the copper fine particles produced by converting the copper hydride of the copper hydride fine particles (b1) into metallic copper are not peeled from the surface of the copper particles (b2) that are primary particles. In addition, there is no substantial difference between the size of the copper hydride fine particles (b1) before heating and the size of the generated copper fine particles. Therefore, the electroconductive copper particle (D) of the structure substantially the same as electroconductive copper particle (B), and about the same average particle diameter is obtained.

60-120 degreeC is preferable, 60-100 degreeC is more preferable, and its 60-90 degreeC of heating temperature is more preferable. If heating temperature is more than the said lower limit, heating time can be shortened and manufacturing cost can be suppressed. If heating temperature is below the said upper limit, it is easy to suppress the increase of the volume resistivity of a conductor film.

As for the pressure at the time of the heating of an electroconductive copper particle (B), -101--50 Pa (gauge pressure) is preferable. If the pressure at the time of heating is -101 kPa or more, it becomes easy to remove excess solvent and to dry, without requiring a large scale apparatus. If the pressure at the time of heating is -50 kPa or less, time can be shortened and manufacturing cost can be suppressed.

(Method for Producing Conductive Copper Particles (E))

As a method of manufacturing electroconductive copper particle (E), electroconductive copper particle (C) is manufactured, the obtained electroconductive copper particle (C) is heated, the copper hydride in electroconductive copper particle (C) is converted into metal copper, The method of making electroconductive copper particle (E) is mentioned. In this case, there is no substantial difference between the size of the conductive copper particles (C) before heating and the size of the conductive copper particles (E) generated by heating.

The heating conditions of electroconductive copper particle (C) can employ | adopt the conditions similar to the heating conditions of electroconductive copper particle (B) in the manufacturing method of electroconductive copper particle (D).

<Conductor Formation Composition>

The composition for conductor formation of this invention contains the electroconductive copper particle and solvent of this invention as an essential component, and contains a resin binder as needed.

As electroconductive copper particle, 1 or more types chosen from the group which consists of said electroconductive copper particle (A)-(E) is preferable, and as electroconductive copper particle (A), electroconductive copper particle (B), and electroconductive copper particle (D) 1 or more types chosen from the group which consists of are more preferable, and any of electroconductive copper particle (A), electroconductive copper particle (B), or electroconductive copper particle (D) is especially preferable.

As a solvent, for example, cyclohexanone, cyclohexanol, terpineol, ethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene Glycol, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, and the like.

As for content of the solvent in the composition for conductor formation, 1-20 mass% is preferable with respect to electroconductive copper particle (100 mass%) from a viewpoint which is easy to adjust to viscosity suitable for printing paste etc.

As a resin binder, the well-known thermosetting resin binder, thermoplastic resin binder, etc. which are used for a metal paste are mentioned. It is preferable that the thermosetting resin binder uses what fully hardening reaction advances at the temperature at the time of hardening. Moreover, it is preferable to use the thermoplastic resin binder which is small in adhesiveness and can maintain the shape of a conductor in a use environment.

Phenolic resin, melamine resin, urea resin, diallyl phthalate resin, unsaturated alkyd resin, epoxy resin, urethane resin, bismaleide triazine resin, silicone resin, acrylic resin, polyester resin etc. are mentioned as a resin binder. Especially, a phenol resin and polyester resin are preferable and a phenol resin is especially preferable.

If the amount of the cured or solidified resin binder is too large, the contact between the conductive copper particles is prevented and the volume resistivity of the conductor film is increased. Therefore, content of the resin binder in the composition for conductor formation needs to be in the range which the quantity of the hardened | cured material or solidified does not interfere with the electroconductivity of electroconductive copper particle.

The content of the resin binder in the composition for forming a conductor can be appropriately selected in consideration of the volume ratio of the volume of the conductive copper particles and the conductive copper particles, and preferably 5 to 50 parts by mass with respect to 100 parts by mass of the conductive copper particles. And 5-20 mass parts is more preferable. If content of a resin binder is more than the said lower limit, the hardness of a conductor film will become more favorable. When content of a resin binder is below the said upper limit, it is easy to suppress the volume resistivity of a conductor film low.

As long as the composition for conductor formation of this invention is a range which does not impair the effect of this invention, you may contain various additives (a leveling agent, a coupling agent, a viscosity modifier, antioxidant, etc.) etc. as needed.

[Manufacturing method]

The composition for conductor formation of this invention can be prepared by mixing the electroconductive copper particle of this invention, a solvent, and the resin binder used as needed. When mixing a thermosetting resin binder in a resin binder, you may perform the heating of the grade which does not harden a thermosetting resin binder and does not lose a volatilization of a solvent. If necessary, the mixing vessel may be replaced with an inert gas for mixing. Thereby, it becomes easy to suppress oxidation of the electroconductive copper particle in mixing.

Since the composition for forming a conductor of the present invention described above contains the conductive copper particles of the present invention which are not easily oxidized in the air, a conductor film having a low volume resistivity and a small change in the volume resistivity over time can be formed. Can be.

<Base material on which the conductor is formed>

The substrate on which the conductor of the present invention is formed has a conductor film formed on the substrate by the substrate and the composition for forming a conductor of the present invention. As for the base material with which the conductor of this invention was formed, it is preferable that a conductor film is a linear wiring body, and it is preferable that it is a printed wiring board.

Examples of the substrate include glass substrates, plastic substrates (such as substrates in films such as polyimide films and polyester films), substrates made of fiber reinforced composite materials (such as glass fiber reinforced resin substrates), ceramic substrates, and metal substrates. .

The volume resistivity of the conductor film is preferably 1.0 × 10 ⁻⁴ Ωcm or less. If the volume resistivity is 1.0 × 10 ⁻⁴ Ωcm or less, the substrate on which the conductor of the present invention is formed can be preferably used as a conductor for an electronic device. The volume resistivity of the conductor film is measured by a four probe ohmmeter.

Moreover, 5% or less is preferable and, as for the change rate of the volume resistivity after one month with respect to the volume resistivity immediately after film-forming in a conductor film, 2% or less is more preferable.

1-100 micrometers is preferable and 5-50 micrometers is preferable at the point which is easy to maintain wiring shape, ensuring the stable electroconductivity, and thickness of a conductor film.

[Manufacturing method]

The base material with which the conductor of this invention was formed can be manufactured by apply | coating the composition for conductor formation of this invention to form a coating layer, and removing volatile components, such as a solvent, from the coating layer, and forming a conductor film. have. In addition, when the composition for conductor formation of this invention contains a thermosetting resin binder, after removing volatile components, such as a solvent, from a coating layer, a conductor film is formed by hardening a thermosetting resin binder. In this case, the obtained conductor film contains the electroconductive copper particle and hardened | cured material of a thermosetting resin binder. In addition, when the composition for conductor formation of this invention contains a thermoplastic resin binder, a conductor film is formed by removing volatile components, such as a solvent, from an application layer. In this case, the obtained conductive film contains electroconductive copper particle and a solid thermoplastic resin.

As a coating method of the composition for conductor formation, well-known methods, such as the screen printing method, the roll coating method, the air knife coating method, the blade coating method, the bar coating method, the gravure coating method, the die coating method, the slide coating method, are mentioned. have.

When the composition for conductor formation contains a thermosetting resin binder, hardening of a thermosetting resin binder can be performed by heating. As a heating method, methods, such as a warm air heating and a thermal radiation, are mentioned. Heating temperature and a heat time can be suitably determined according to the characteristic calculated | required by a conductor film. When the composition for conductor formation contains electroconductive copper particle (B) or electroconductive copper particle (C) as electroconductive copper particle, simultaneously with hardening of a thermosetting resin binder, the copper hydride contained in these electroconductive copper particle is a metal. Converted to copper.

When the composition for conductor formation contains a thermoplastic resin binder, and when it contains electroconductive copper particle (B) or electroconductive copper particle (C) as electroconductive copper particle, heating at the time of removing volatile components, such as a solvent, The copper hydride contained in these electroconductive copper particle is converted into metal copper by this.

As for heating temperature, 100-300 degreeC is preferable. If heating temperature is 100 degreeC or more, the solvent contained in the composition for conductor formation will fully volatilize. Moreover, hardening of a thermosetting resin advances easily. If heating temperature is 300 degrees C or less, a plastic film can be used as a base material which forms a conductor film. What is necessary is just to make hardening time into time which a resin binder fully hardens according to hardening temperature.

The environment for forming the conductor film is not particularly limited, and may be in air or may be nitrogen with less oxygen. Especially, air is preferable from a viewpoint of simplifying manufacturing facilities.

The substrate on which the conductor of the present invention described above is formed has a conductor film having a low volume resistivity and a small change in volume resistivity over time.

Example

Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by the following description. Examples 1-5 are Examples, and Examples 6-10 are comparative examples.

[How to measure]

The measuring method of each numerical value in a present Example is shown below.

(Average particle size)

The average particle diameter of the copper particle before reduction process, and the obtained electroconductive copper particle was measured as follows. In the case of primary particles, particle diameters of 100 particles randomly selected from the SEM images obtained by SEM (Hitachi Corporation make, S-4300) were measured and averaged. In the case of secondary particles, the particle diameters of 100 particles randomly selected from the TEM images obtained by a transmission electron microscope (TEM) were measured and averaged.

(Chloride concentration in the reaction system)

The chloride ion concentration of the reaction system was measured by a chlorine ion electrode (Tomkei Kay Co., Ltd., HM-20P).

PH of reaction system

The pH of the reaction system was measured by a pH meter (Tomkei Kay Co., Ltd., HM-20P).

(Redox potential of reaction system)

The redox potential (ORP) of the reaction system was measured by an ORP meter (manufactured by Todike Kay Co., Ltd., RM-12P).

(Chlorine atom content of electroconductive copper particle)

Content of the chlorine atom in the obtained electroconductive copper particle was calculated | required by fluorescence X-ray analysis (The Rigaku Electric Co., Ltd. make, ZSX100e).

(Surface Oxygen Content of Conductive Copper Particles)

The surface oxygen amount of the obtained electroconductive copper particle calculates | requires surface oxygen concentration [atomic%] and surface copper concentration [atomic%] by X-ray photoelectron spectroscopy (The Albak Pais company make, ESCA5500), and makes surface oxygen concentration into surface copper concentration It was calculated by dividing.

(Solubility Test of Chlorine Atoms in Conductive Copper Particles)

When all the chlorine atoms contained in the conductive copper particles were eluted in distilled water, the conductive copper particles in an amount such that the concentration of chloride ions in the distilled water became 100 mass ppm were immersed in distilled water (dissolved oxygen concentration of 1 mass ppm or less). . Subsequently, the distilled water in which the electroconductive copper particle was immersed was stirred at 1000 rpm for 5 second using the test tube mixer (made by As One, HM-01) at 20 degreeC, and the chloride ion concentration eluted in the distilled water was chlorine ion. Measurement was made using an electrode.

(Thickness of the conductive film)

The thickness of the conductor film was measured by DEKTAK3 (manufactured by Veeco metrology Group).

(Surface Resistance of Conductor Film)

The surface resistance of the conductor film was measured immediately after film formation with a four probe resistance gauge (manufactured by Mitsubishi Emulsion Co., Ltd., model: lorestaIP MCP-T250). Moreover, the surface resistance value of the conductor film after 1 month passed was measured again, and the change rate (unit:%) with respect to the surface resistance value immediately after film-forming was calculated | required.

(Volume Resistivity of Conductor Film)

The product of the thickness of the conductor film and the surface resistance of the conductor film measured by the above method was obtained, and the volume resistivity was obtained.

[Example 1]

(Manufacture of electroconductive copper particle A1)

In a glass beaker, 100 g of copper particles (manufactured by Mitsui Metal Co., Ltd., brand name "1400YP", average primary particle size of 7 µm) are dispersed in 1800 g of distilled water, and a compound for producing 30 g of formic acid and chloride ions as a pH adjuster. As an example, 35 mass% hydrochloric acid was added, and the chloride ion concentration in the reaction system was 10 mass ppm. Subsequently, the beaker was put into a 40 degreeC water bath, 180g of 50 mass% hypophosphoric acid aqueous solution was added, stirring, the reaction system (alpha) was formed, and stirring was continued for 30 minutes. Table 1 shows the pH of the reaction system (α) immediately after the addition of hypophosphoric acid, the pH of the reaction system (α) after the completion of the reaction, and the redox potential (ORP) of the reaction system (α) after the completion of the reaction.

After completion of stirring, the precipitate was separated by filtration. The precipitate was redispersed in 600 g of distilled water, and thereafter, the precipitate was precipitated by centrifugation to separate the precipitate. Under reduced pressure of -35 kPa (gauge pressure), the precipitate was heated at 80 ° C for 60 minutes, and the remaining moisture was evaporated to remove gradually, thereby obtaining the conductive copper particles A1.

Content of the chlorine atom in electroconductive copper particle A1 was 100 mass ppm. In addition, when the water solubility test of the electroconductive copper particle A1 was performed, the density | concentration of the chloride ion eluted in distilled water was less than 5 mass ppm. That is, the chlorine atom contained in electroconductive copper particle A1 was a water-insoluble form. In addition, the average particle diameter of electroconductive copper particle A1 was 7 micrometers.

(Preparation of the composition for conductor film formation)

1.2g of electroconductive copper particle A1 was added to the resin solution which melt | dissolved 0.26g of phenol resins (made by group A Chemical company, brand name "Resort top PL6220") in 0.15g of ethylene glycol monobutyl ether acetate. This mixture was placed in a mortar and mixed at room temperature to obtain a composition for forming a conductor film. The addition amount of the phenol resin was 11 mass parts with respect to 100 mass parts of electroconductive copper particle A1.

(Formation of Conductor Film)

The obtained composition for conductor film formation was apply | coated to a glass substrate, it heated at 150 degreeC for 1 hour, hardened | cured the phenol resin, the conductor film of thickness 20micrometer was formed, and the volume resistivity of this conductor film was measured.

[Example 2]

(Manufacture of electroconductive copper particle A2)

Conductive copper particles A2 were obtained in the same manner as Example 1 except that the chloride ion concentration in the reaction system (α) was 25 mass ppm.

Content of the chlorine atom of the obtained electroconductive copper particle A2 was 250 mass ppm. Moreover, the water-soluble test of electroconductive copper particle A2 showed that the concentration of the chloride ion eluted in distilled water was less than 5 mass ppm. That is, the chlorine atom contained in electroconductive copper particle A2 was a water-insoluble form. In addition, the average particle diameter of electroconductive copper particle A2 was 7 micrometers.

(Preparation of the composition for conductor film formation)

Using the electroconductive copper particle A2, it carried out similarly to Example 1, and obtained the composition for conductor film formation.

(Formation of Conductor Film)

Using the obtained composition for forming a conductor film, a conductor film was formed in the same manner as in Example 1, and the volume resistivity thereof was measured.

[Example 3]

(Manufacture of electroconductive copper particle D1)

In a glass beaker, 100 g of copper particles (Mitsui Metal Co., Ltd. make, brand name "1400YP", an average primary particle diameter of 7 micrometers) was disperse | distributed to 1800 g of distilled water. Next, 15 g of formic acid as a pH adjuster, 39 g of copper formate as a water-soluble copper compound, and 35 mass% hydrochloric acid were added as a compound to generate chloride ions, and the chloride ion concentration in the reaction system was 10 mass ppm. Subsequently, the beaker was put into a 40 degreeC water bath, 180g of 50 mass% hypophosphorous acid aqueous solution was added, stirring, the reaction system ((beta)) was formed, and stirring was continued for 30 minutes. After completion of stirring, the conductive copper particles D1 were obtained by treating the reaction system (β) in the same manner as the reaction system (α) of Example 1. In this example, conductive copper particles B1 having a form in which copper hydride particles, which are secondary particles are attached, are formed on the surface of copper particles, which are primary particles, and are heated at 80 ° C. for 60 minutes to volatilize residual moisture. It is thought that copper hydride microparticles | fine-particles are converted into copper microparticles | fine-particles, and electroconductive copper particle D1 was obtained.

Content of the chlorine atom of the obtained electroconductive copper particle D1 was 150 mass ppm. In addition, when the water solubility test of the electroconductive copper particle D1 was performed, the density | concentration of the chloride ion eluted in distilled water was less than 5 mass ppm. That is, the chlorine atom contained in the electroconductive copper particle D1 was a water-insoluble form. In addition, the average particle diameter of the electroconductive copper particle D1 was 8 micrometers.

(Preparation of the composition for conductor film formation)

1.2g of electroconductive copper particle D1 was added to the resin solution which melt | dissolved 0.15g of amorphous polyester resin (The Toyo Spinning company make, brand name "Viron 300") in 0.35g of cyclohexanone. This mixture was placed in a mortar and mixed at room temperature to obtain a composition for forming a conductor film. The addition amount of amorphous polyester resin was 11 mass parts with respect to 100 mass parts of electroconductive copper particle D1.

(Formation of Conductor Film)

The obtained composition for forming a conductor film was applied to a glass substrate, heated at 150 ° C. for 1 hour to cure an amorphous polyester resin, a conductor film having a thickness of 20 μm was formed, and the volume resistivity of the conductor film was measured.

[Example 4]

(Manufacture of electroconductive copper particle D2)

Conductive copper particles D2 were obtained in the same manner as in Example 3 except that the chloride ion concentration in the reaction system (β) was 15 mass ppm.

Content of the chlorine atom of the obtained electroconductive copper particle D2 was 400 mass ppm. In addition, when the water solubility test of the electroconductive copper particle D2 was performed, the density | concentration of the chloride ion eluted in distilled water was 8 mass ppm. That is, the chlorine atom contained in the electroconductive copper particle D2 was a water-insoluble form. In addition, the average particle diameter of the electroconductive copper particle D2 was 8 micrometers.

(Preparation of the composition for conductor film formation)

Using the electroconductive copper particle D2, it carried out similarly to Example 3, and obtained the composition for conductor film formation.

(Formation of Conductor Film)

Using the obtained composition for forming a conductor film, a conductor film was formed in the same manner as in Example 1, and the volume resistivity thereof was measured.

[Example 5]

(Manufacture of electroconductive copper particle D3)

Conductive copper particles D3 were obtained in the same manner as in Example 3 except that the chloride ion concentration in the reaction system (β) was 25 mass ppm.

Content of the chlorine atom of the obtained electroconductive copper particle B3 was 700 mass ppm. In addition, when the water solubility test of the electroconductive copper particle D3 was performed, the density | concentration of the chloride ion eluted in distilled water was 10 mass ppm. That is, chlorine contained in electroconductive copper particle D3 was a water-insoluble form. In addition, the average particle diameter of the electroconductive copper particle D3 was 8 micrometers.

(Preparation of the composition for conductor film formation)

Using the electroconductive copper particle D3, it carried out similarly to Example 3, and obtained the composition for conductor film formation.

(Formation of Conductor Film)

Using the obtained composition for forming a conductor film, a conductor film was formed in the same manner as in Example 1, and the volume resistivity thereof was measured.

[Example 6]

(Production of conductive copper particles)

In a glass beaker, 100 g of copper particles (made by Mitsui Metal Mining Co., Ltd., brand name "1400YP", an average primary particle diameter of 7 µm) were dispersed in 1800 g of distilled water, and 30 g of formic acid was added, and then the beaker was water of 40 ° C. Conductive copper particles F1 were obtained in the same manner as in Example 1, except that 90 g of sulfuric acid was added while stirring into the bath to form a reaction system.

Content of the chlorine atom of the obtained electroconductive copper particle F1 was less than 50 mass ppm.

(Preparation of the composition for conductor film formation)

Using the electroconductive copper particle F1, it carried out similarly to Example 1, and obtained the composition for conductor film formation.

(Formation of Conductor Film)

Using the obtained composition for forming a conductor film, a conductor film was formed in the same manner as in Example 1, and the volume resistivity thereof was measured.

[Example 7]

(Production of conductive copper particles)

In a glass beaker, 100 g of copper particles (Mitsui Metal Co., Ltd., brand name "1400YP", an average primary particle diameter of 7 µm) are dispersed in 1800 g of distilled water, the beaker is placed in a water bath at 40 ° C, and then formic acid is stirred. Conductive copper particles F2 were obtained in the same manner as Example 1 except that 72 g was added to form a reaction system.

Content of the chlorine atom of the obtained electroconductive copper particle F2 was less than 50 mass ppm.

(Preparation of the composition for conductor film formation)

Using the electroconductive copper particle F2, it carried out similarly to Example 1, and obtained the composition for conductor film formation.

(Formation of Conductor Film)

Using the obtained composition for forming a conductor film, a conductor film was formed in the same manner as in Example 1, and the volume resistivity thereof was measured.

[Example 8]

(Production of conductive copper particles)

In a glass beaker, 100 g of copper particles (Mitsui Metal Co., Ltd., trade name "1400YP", average primary particle diameter of 7 µm) were dispersed in 1800 g of distilled water, 35 mass% hydrochloric acid was added, and the concentration of the chlorine atom in the reaction system was 100. After setting it as mass ppm and putting a beaker in the water bath of 40 degreeC, conducting copper particle F3 was obtained like Example 1 except having added 72 g of formic acid, stirring, and forming the reaction system.

The chlorine content of the obtained electroconductive copper particle F3 was 300 mass ppm. Moreover, the water-soluble test of electroconductive copper particle F3 showed that the density | concentration of the chloride ion eluted in distilled water was 30 mass ppm. That is, the chlorine contained in electroconductive copper particle F3 was a water-soluble form.

(Preparation of the composition for conductor film formation)

Using the electroconductive copper particle F3, it carried out similarly to Example 1, and obtained the composition for conductor film formation.

(Formation of Conductor Film)

Using the obtained composition for forming a conductor film, a conductor film was formed in the same manner as in Example 1, and the volume resistivity thereof was measured.

[Example 9]

(Production of conductive copper particles)

In the same manner as in Example 7, after obtaining the conductive copper particles, hydrochloric acid was further added to the conductive copper particles so that the content of the chlorine atom was 100 mass ppm, thereby obtaining the conductive copper particles F4.

Content of the chlorine atom of the obtained electroconductive copper particle F4 was 100 mass ppm. Moreover, the water-soluble test of electroconductive copper particle F4 showed that the density | concentration of the chloride ion eluted in distilled water was 90 mass ppm. That is, chlorine contained in electroconductive copper particle F4 was a water-soluble form.

(Preparation of the composition for conductor film formation)

Using the electroconductive copper particle F4, it carried out similarly to Example 1, and obtained the composition for conductor film formation.

(Formation of Conductor Film)

Using the obtained composition for forming a conductor film, a conductor film was formed in the same manner as in Example 1, and the volume resistivity thereof was measured.

[Example 10]

(Preparation of conductive copper particles)

In the same manner as in Example 7, after obtaining the conductive copper particles, hydrochloric acid was further added to the conductive copper particles so that the content of the chlorine atom was 1,000 mass ppm, thereby obtaining the conductive copper particles F5.

Content of the chlorine atom of the obtained electroconductive copper particle F5 was 1,000 mass ppm. In addition, when the water solubility test of the electroconductive copper particle F5 was performed, the density | concentration of the chloride ion eluted in distilled water was 90 mass ppm. That is, the chlorine contained in electroconductive copper particle F5 was a water-soluble form.

(Preparation of the composition for conductor film formation)

Using the electroconductive copper particle F5, it carried out similarly to Example 1, and obtained the composition for conductor film formation.

(Formation of Conductor Film)

Using the obtained composition for forming a conductor film, a conductor film was formed in the same manner as in Example 1, and the volume resistivity thereof was measured.

Table 1 shows the characteristics and evaluation results of the reaction system, the conductive copper particles, and the conductor film in Examples 1 to 10.

As shown in Table 1, the conductor film of Examples 8-10 which used the electroconductive copper particle containing the chlorine atom of the water-soluble form, and Example 6 and 7, which used the electroconductive copper particle whose content of a chlorine atom is less than 50 mass ppm are formed into a film. Even if the volume resistivity was high immediately after, or the volume resistivity immediately after film-forming was low, the volume resistivity increased by storage. On the other hand, the conductor film of Examples 1-5 which used the electroconductive copper particle of this invention containing 50-1000 mass ppm of chlorine atoms of a water-insoluble form was low in volume resistivity, and the change rate after 1 month passed was also low.

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various modifications and changes can be made without departing from the scope and spirit of the invention.

This application is based on the JP Patent application 2010-226632 of an application on October 6, 2010, The content is taken in here as a reference.

Industrial availability

The composition for electroconductive copper particle and conductor film formation of this invention can be used suitably for various uses, such as formation and repair of the wiring pattern in a printed wiring board, etc., interlayer wiring in a semiconductor package, bonding of a printed wiring board and an electronic component.

Claims (6)

Electroconductive copper particle which contains 50-1000 mass ppm of chlorine atoms with respect to the gross mass of particle | grains, and the chlorine atom exists in water-insoluble form. The method of claim 1,
Electroconductive copper particle whose average particle diameter is 0.01-20 micrometers. The composition for conductor formation containing the electroconductive copper particle of Claim 1 or 2 and a solvent. The method of claim 3, wherein
The composition for conductor formation containing a resin binder. A substrate having a conductor having a substrate and a conductor film formed on the substrate by the composition for forming a conductor according to claim 3 or 4. As a manufacturing method of the electroconductive copper particle of Claim 1,
The manufacturing method of electroconductive copper particle which has a process of reducing at least one of copper particle and copper (II) ion in the reaction system which contains chloride ion and is pH 3 or less and whose oxidation reduction potential is 220 kPa or less.