JP2019121568A - Manufacturing method of solder adhesive metal paste conductive film - Google Patents

Abstract

To provide a manufacturing method of a solder adhesive metal paste conductive film capable of manufacturing a metal paste conductive film good in solder wettability and high in conductivity.SOLUTION: There is provided a manufacturing method of a solder adhesive metal paste conducive film having: a process for coating a substrate with a metal paste composition containing a metal particle (A), a resin binder (B), and a diluent (C) to form a coated film of the metal paste composition; a process for semi-curing the coated film of the metal paste composition by heating to form a metal paste conductive film; a process for coating the metal paste conductive film with a solder paste; and a process for melting the solder paste by heating.SELECTED DRAWING: None

Description

  The present invention relates to a method of manufacturing a solder-adhered metal paste conductive film.

In recent years, in the field of electronic materials and the like, metal paste compositions containing metal powder in resin as a means for securing electrical continuity such as circuit formation of printed wiring boards, formation of lead wires of touch panels and formation of various electrical junctions. There is widely used a method of drawing a pattern by printing and curing it by applying light or heat to form a conductive wiring. In particular, a metal paste used for the metal paste composition is generally widely used, since it is excellent in oxidation resistance and low in volume resistivity and silver paste using silver powder.
Furthermore, at the time of device fabrication, it is necessary to electrically join the wires produced by the above-mentioned metal paste composition, or wires and elements, and as a method of joining, joining using a solder material such as solder paste or bar solder ( Soldering is mainly used. However, these metal paste compositions contain about 20% by weight of resin, and when viewed from the volume ratio, they contain a large amount of resin with low solder wettability in wiring, so metal foils Soldering was difficult compared to. Moreover, although the solderable metal paste composition is also proposed by patent document 1, 2, when soldering the silver paste as described in these documents, it is a cause of the high melt | dissolution rate to the solder which silver has. The so-called silver corrosion phenomenon occurs in which the silver powder in the conductive film obtained by curing the silver paste dissolves in the molten solder. Due to this decrease in silver corrosion, the strength can not be maintained at the time of bonding with the lead wire, and it is also difficult to maintain the conductivity for a long time under a high temperature and high humidity environment.

On the other hand, development of a metal paste composition using copper as an electrically conductive composition has been advanced in recent years next to silver, which is low in volume resistivity, inexpensive, and excellent in migration resistance. Copper is considered to be able to solve the above-mentioned problem of joint strength because copper does not have a rate of dissolution in a solder alloy as high as silver.
However, the conductive film formed from copper paste is more easily oxidized than the conductive film formed from silver paste, and there is a problem that the conductivity is lowered. An attempt is made to maintain the As a method for suppressing the oxidation of the conductive film formed from the copper paste, for example, in Patent Document 3, the chemical treatment is applied to the surface of the copper particles to suppress the oxidation, and the conductivity when forming the copper paste conductive film Maintain.
Further, as a method for suppressing the oxidation of the conductive film relating to the resin binder, thermosetting resin such as resol-type phenolic resin which easily promotes the contact between the metal particles by shrinkage at the time of curing and has reducibility can be obtained. Most of them are used for binders. However, when bonding is performed using a solder material on a metal paste conductive film containing such a resol-type phenolic resin, there is a problem that the solder wettability is low and the solder bonding becomes difficult. Although patent document 4 is described regarding the metal paste composition which used resol type phenol resin as a binder which improved solder wettability, it has not been able to be compatible in electroconductivity and solder wettability.

JP 7-14429 A Unexamined-Japanese-Patent No. 2002-212492 International Publication No. 2016/199811 JP, 2006-28213, A

As described above, in the prior art, it is difficult to obtain a metal paste conductive film having good solder wettability and high conductivity.
An object of the present invention is to provide a method for producing a solder-adhered metal paste conductive film, which is capable of producing a metal paste conductive film having good solder wettability and high conductivity.

As a result of intensive investigations, the present inventors can apply a metal paste composition having a specific composition to a substrate and cure under specific conditions to obtain a metal paste conductive film with good solder wettability. The present invention has been completed.
That is, the present invention provides the following [1] to [7] as the gist.

[1] A step of applying a metal paste composition containing a metal particle (A), a resin binder (B), and a diluent (C) to a substrate to form a coated film of the metal paste composition, and the metal paste composition Solder adhesion comprising: a step of semi-curing the coating film of the above to form a metal paste conductive film, a step of applying a solder paste on the metal paste conductive film, and a step of melting the solder paste by heating Method of manufacturing metal paste conductive film.
[2] The metal particles (A) in the metal paste composition are selected from the group consisting of gold, silver, copper, platinum, palladium, rhodium, nickel, zinc, tin, and aluminum, and an alloy containing a metal selected therefrom The manufacturing method of the solder adhesion metal paste conductive film as described in said [1] which is at least 1 type of particle | grains selected.
[3] The method for producing a soldered metal paste conductive film according to the above [1] or [2], wherein the metal particles (A) in the metal paste composition include particles composed of copper particles or an alloy containing copper .
[4] The above-mentioned [1], wherein the resin binder (B) in the metal paste composition contains at least one thermosetting resin selected from the group consisting of resol type phenol resin, epoxy resin, and melamine resin. The manufacturing method of the solder adhesion metal paste conductive film in any one of-[3].
[5] The manufacturing method of the solder adhesion metal paste conductive film in any one of said [1]-[4] that the resin binder (B) in the said metal paste composition contains resol type phenol resin.

[6] The manufacturing method of the solder adhesion metal paste conductive film in any one of said [1]-[5] in which the metal particle (A) in the said metal paste composition contains surface coating metal particle.
[7] In the metal paste composition, the metal particles (A) are composed of surface-coated copper particles, and the surface-coated copper particles are chemically bonded to the copper particles and / or physically attached to the surface of the copper particles. A first coating layer of an amine compound represented by the formula (1) bonded by bonding, and an aliphatic mono-carbon having 8 to 20 carbon atoms bonded to the amine compound by chemical bonding on the first coating layer A surface-coated copper particle having a carboxylic acid second coating layer, wherein the resin binder (B) is a resol type phenolic resin, and the resin binder (B) is 10 per 100 parts by mass of the metal particle (A). The manufacturing method of the solder adhesion metal paste conductive film in any one of said [1]-[6] in which -30 mass parts and 10-30 mass parts of diluents (C) are contained.

[In the formula (1), m is an integer of 0 to 3, n is an integer of 0 to 2, and when n = 0, m is any of 0 to 3 and n = 1 or n = 2 m is any one of 1 to 3. ]

  According to the method for producing a solder-adhesion metal paste conductive film of the present invention, it is possible to obtain a solder-adhesion metal paste conductive film which is excellent in solder wettability and has high conductivity.

It is a figure which shows the DSC chart about Example 2-5 of this invention, and Comparative Example 2-3. It is an observation image of the solder adhesion metal paste electrically conductive film of Example 2-5 (when solder | pewter wettability is (circle)). It is an observation image of the solder adhesion metal paste electrically conductive film of Comparative Example 2-3 (when solder wettability is x).

  The method for producing a solder adhesion metal paste conductive film of the present invention comprises applying a metal paste composition containing metal particles (A), a resin binder (B) and a diluent (C) to a substrate and applying a coating film of the metal paste composition A step of forming, a step of semi-curing the coating film of the metal paste composition by heating to form a metal paste conductive film, a step of applying a solder paste on the metal paste conductive film, and heating the solder paste And melting.

Hereinafter, embodiments of the present invention will be described in detail.
In the present specification, when preferable numerical ranges (eg, the range of contents, etc.) are described stepwise, the lower limit value and the upper limit value can be respectively combined independently. For example, in the description "preferably 10 to 100, more preferably 20 to 90", it may be "10 to 90" or "20 to 100".

<< metal paste composition >>
[Metal particle (A)]
The metal paste composition of the present invention contains metal particles (A). The metal particles (A) are, for example, at least one selected from the group consisting of gold, silver, copper, platinum, palladium, rhodium, nickel, zinc, tin, and aluminum, and an alloy containing a metal selected from these. Particles of The metal particles (A) may be used alone or in combination of two or more.

  The conductivity of the metal paste conductive film (hereinafter, also simply referred to as a conductive film) obtained from the metal paste composition using these metal particles (A) is greatly affected by the volume resistivity of the metal particles. In particular, silver and copper have low volume specific resistance values, so from the viewpoint of the performance of a conductive film as a conductive wiring at the time of device fabrication, silver particles, copper particles, or any of these for metal particles (A) It is preferable to use particles made of an alloy containing a metal of the following. The conductive film produced using copper particles is less likely to cause ion migration (electrodeposition) in which metal atoms are ionized and pulled into an electric field and moved when current is applied under high temperature and high humidity. Preferably, the particles contain particles of copper particles or an alloy containing copper particles, more preferably copper particles, or particles of an alloy containing copper, more preferably copper particles. Is more preferred. If ion migration occurs on the wiring circuit, a short circuit may occur between the circuits, which may reduce the reliability of the wiring circuit.

Moreover, it is preferable that a metal particle (A) contains the surface coating metal particle which surface-treated the metal particle. When the metal particles (A) contain surface-coated metal particles, the oxidation resistance of the metal particles (A) and the dispersibility in the resin binder can be improved, and a metal paste composition containing the metal particles (A) Can be printed and cured to increase the conductivity of the formed wiring.
In particular, when copper particles are used for the metal particles (A), the copper particles easily form an oxide that causes a decrease in conductivity under the atmosphere, and therefore, it is preferable to use the surface as a coating. Therefore, from the viewpoint of improving the conductivity and the oxidation resistance, the metal particles (A) preferably contain surface-coated copper particles, and are more preferably composed of surface-coated copper particles.

The surface-coated copper particles may be those having a coating layer on the surface of the copper particles, but from the viewpoint of further improving the oxidation resistance, the metal of the surface of the copper particles and the chemical bond or A first coating layer formed of an amine compound represented by the following formula (1) bonded by physical bonding, and the carbon number 8 bonded to the amine compound by a chemical bond on the first coating layer It is more preferable to have a second covering layer formed of -20 aliphatic monocarboxylic acids. The use of such surface-coated copper particles is preferable because highly conductive wiring can be formed.

[In the formula (1), m is an integer of 0 to 3, n is an integer of 0 to 2, and when n = 0, m is any of 0 to 3 and n = 1 or n = 2 m is any one of 1 to 3. ]

The first coated layer of the surface-coated copper particles is a layer formed of an amine compound which is chemically and / or physically bonded to and adsorbed on the surface of the copper particles. In terms of oxidation resistance, it is ideal that the amine compound uniformly coats the surface of the copper particles in the form of a monomolecular film, but in practice it is difficult to be such an ideal state. Some copper particles may have a portion on which the amine compound is not adsorbed, or a portion in which two or more molecules are stacked and adsorbed.
Therefore, the first covering layer in the present invention includes not only a layer in which the amine compound uniformly coats the copper particle surface but also a covering layer in which the copper particle surface on which the amine compound is not adsorbed is partially present. .
In addition, it can be confirmed by IR measurement of the copper particle surface that the amine compound adsorb | sucks to the copper particle surface and it forms a 1st coating layer.
Here, the adsorption by the chemical bond means that the amine compound forms a bond with the copper particle surface by electrostatic interaction and is adsorbed on the copper particle surface. The electrostatic interaction mentioned here refers to hydrogen bonding, interaction between ions (ion bonding) and the like. Further, the adsorption by physical bonding means that the copper particles are adsorbed by physical adsorption by van der Waals force. In particular, since an amino group is highly electron donative and it is considered that the amino group forms a bond by forming a coordination to copper, the amine compound is mainly formed of copper particles by a chemical bond by electrostatic interaction. It is thought that it adsorbs to the surface and forms the first covering layer. However, adsorption due to physical binding may partially exist.
In addition, there may be a portion in which two or more molecules of amine compounds are bonded by, for example, hydrogen bonding or the like and laminated.

The second coated layer of the surface-coated copper particles is a layer laminated on the first coated layer, and is an aliphatic monocarbon having 8 to 20 carbon atoms which is bonded to the amine compound of the first coated layer by a chemical bond It is a layer of acid.
Here, chemical bonding means that the carboxyl group of aliphatic monocarboxylic acid and the amino group of an amine compound are bonded by electrostatic interaction. The electrostatic interaction mentioned here refers to hydrogen bonding, interaction between ions (ion bonding) and the like. That is, the second covering layer is a layer of aliphatic monocarboxylic acid bonded to the amine compound of the first covering layer by electrostatic interaction. Ideally, it is preferable that the amine compound of the first covering layer and the aliphatic monocarboxylic acid react 1: 1 to form the second covering layer, but in practice, such an ideal state is obtained. It is difficult to be. Therefore, there may be an amine compound of the first coating layer not partially bound to aliphatic monocarboxylic acid, and in the second coating layer, two or more molecules of aliphatic monocarboxylic acid are laminated due to physical adsorption or the like. There may be a portion that is adsorbed.
Therefore, the second covering layer in the present invention means, similarly to the first covering layer, not only a layer in which the aliphatic monocarboxylic acid uniformly coats the first covering layer but also an aliphatic monocarboxylic acid with an amine compound. It is also intended to include a cover layer which is formed such that a part which is not bonded is partially present.
In addition, it can confirm that the aliphatic monocarboxylic acid adsorb | sucks and 2nd coating layer is formed by IR measurement of the copper particle surface similarly to 1st coating layer.
Furthermore, when there is a copper particle surface to which an amine compound is not bound, there may be a portion where aliphatic monocarboxylic acid is directly adsorbed to the copper particle surface, such surface-coated copper particles Are also within the scope of the present invention.

  The amine compound which forms the said 1st coating layer is an amine compound represented by the said Formula (1). Specifically, hydrazine, methylenediamine, ethylenediamine, 1,3-propanediamine, dimethylenetriamine, trimethylenetetramine, tetramethylenepentamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenetriamine, tripropylenetriamine Propylene tetraamine, tetrapropylene pentaamine and the like can be mentioned. The first covering layer may be formed of one of these amine compounds, or may be formed using a plurality of types.

When the value of m in the formula (1) is 3 or less, the number of amino groups contributing to chemical bonding and reducibility per unit area on the surface of the copper particle is increased, so that the desired oxidation resistance is obtained. Easy to get In addition, when n in the formula (1) is 2 or less, the molecular chain is relatively short, steric hindrance with the adjacent amine compound does not easily occur at the time of coating, and the copper particle surface can be sufficiently covered. It is easy to get sex.
The aliphatic monocarboxylic acid having 8 to 20 carbon atoms forming the second covering layer used in the present invention is a linear saturated aliphatic monocarboxylic acid having 8 to 20 carbon atoms, a linear unsaturated having 8 to 20 carbon atoms. Aliphatic monocarboxylic acids, branched saturated aliphatic monocarboxylic acids having 8 to 20 carbon atoms, and branched unsaturated aliphatic monocarboxylic acids having 8 to 20 carbon atoms can be mentioned. Specific examples of the linear saturated aliphatic monocarboxylic acid having 8 to 20 carbon atoms include caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, margarine Examples include acids, stearic acid, nonadecanoic acid and arachidic acid. Examples of the linear unsaturated aliphatic monocarboxylic acid having 8 to 20 carbon atoms include myristoleic acid, palmitoleic acid, petroselinic acid and oleic acid. As a C8-C20 branched saturated aliphatic monocarboxylic acid, 2-ethyl hexanoic acid etc. are mentioned. The aliphatic monocarboxylic acids may be used alone or in combination of two or more.
If the carbon number is 8 or more, the dispersibility of the surface-coated copper particles is likely to be improved because the alkyl chain length is long. When the carbon number is 20 or less, the hydrophobicity of the aliphatic monocarboxylic acid decreases and the compatibility with the binder deteriorates, and when the metal paste composition is prepared, the aliphatic monocarboxylic acid is removed from the second coating layer. It becomes easy to prevent releasing to the binder side.
From the viewpoint of further improving the dispersibility of the surface-coated copper particles in the paste composition and reducing the amount of free aliphatic monocarboxylic acid in the metal paste composition, an aliphatic which forms a second covering layer As a monocarboxylic acid, a C10-C18 aliphatic monocarboxylic acid is preferable. Furthermore, a linear saturated aliphatic monocarboxylic acid is more likely to have a close-packed structure than an aliphatic monocarboxylic acid having a branched chain or an unsaturated bond, and has a coating with few voids, and thus a linear C10-C18 linear It is more preferred to use a saturated aliphatic monocarboxylic acid.

The surface-coated copper particles are preferably, as described above, two coatings of the first coating layer with the amine compound represented by the formula (1) and the second coating layer of the aliphatic monocarboxylic acid having 8 to 20 carbon atoms. A layer is formed on the copper particle surface.
The amine compound has the reducing effect of the oxide on the surface of the copper particle and the oxidation suppressing effect because the amino group has reducibility.
In addition, amine compounds are more aliphatic than aliphatic monocarboxylic acids because they have higher coordination ability to copper due to the effect of nitrogen lone pair of amino group than aliphatic monocarboxylic acids, and they bind to the surface of copper particles with stronger bonds than aliphatic monocarboxylic acids. It is believed that the surface coverage is higher than monocarboxylic acid. In addition, amine compounds tend to form bonds by electrostatic interaction with aliphatic monocarboxylic acids. Therefore, after covering the surface of the copper particle with an amine compound having a high surface coverage, by covering the outer side with an aliphatic monocarboxylic acid, the surface is higher than directly covering the aliphatic monocarboxylic acid on the copper particles. Aliphatic monocarboxylic acids can be coated on copper particles at a coverage rate. Therefore, such surface-coated copper particles have higher oxidation resistance than copper particles coated only with aliphatic monocarboxylic acid due to the oxidation inhibition effect of the amine compound and high coverage of aliphatic monocarboxylic acid. There is.

Furthermore, as described above, aliphatic monocarboxylic acids are considered to have their carboxyl groups bonded to the amino groups of amine compounds through electrostatic interaction. That is, it is considered that the second covering layer is formed by directing the carboxyl group of the hydrophilic group to the side of the first covering layer of the amine compound and the alkyl group of the hydrophobic group to the outside. Accordingly, the surface-coated copper particles of the present invention having the second coating layer of aliphatic monocarboxylic acid can suppress aggregation of copper particles and also suppress detachment of the amine compound than copper particles coated only with an amine compound. can do.
Confirmation that the surface-coated copper particles are coated with the amine compound and the aliphatic monocarboxylic acid is possible by measuring the infrared absorption (IR) spectrum of the surface-coated copper particles.

The average particle diameter D50 of the metal particles (A) is preferably 0.8 μm or more and 12 μm or less. The metal paste composition produced using the metal particle whose average particle diameter is the said range can form smooth surface and wiring shape, even when fine wiring is formed by screen printing.
In the present specification, the particle size and the average particle size D50 refer to values measured by a laser diffraction microtrack particle size distribution measuring apparatus. As the measuring apparatus, for example, Microtrack particle size distribution measuring apparatus MT3000II series (laser diffraction / scattering method) manufactured by Microtrack Bell Inc. can be exemplified.

The shape of the metal particles (A) used in the present invention may be spherical, plate-like, flake-like, dendritic, rod-like, or fibrous, and may be hollow or porous. . Furthermore, the shell and core may be in the form of a core-shell which is another substance. Among these, as a shape of metal particle (A), it is preferable that it is plate shape. In the case of the metal paste composition containing plate-like particles, when the conductive film is formed to form the wiring on the substrate, the curing shrinkage of the metal paste composition in the planar direction of the substrate is suppressed due to the particle shape. Therefore, the deformation is suppressed and the adhesion to the substrate is excellent.
Moreover, the metal particles used for a metal particle (A) may use the metal particle of the same shape, and may use together the metal particle of a different shape.

[Resin binder (B)]
The metal paste composition of the present invention contains a resin binder (B). 10-30 mass parts is preferable with respect to 100 mass parts of metal particles (A), and, as for content of a resin binder (B), 15-25 mass parts is more preferable. When the content of the resin binder (B) is 10 parts by mass or more, the adhesion between metal particles when forming a conductive film is good, and has sufficient fluidity at the time of printing of the metal paste composition. When the content of the resin binder (B) is 30 parts by mass or less, the proportion of metal particles exposed on the surface of the conductive film increases, and alloy formation between the solder and the metal particles easily occurs, and the solder wettability is improved. . Moreover, if it is 25 mass parts or less, when resin binder (B) is resin which has reducibility, the conductive film of low resistance value is easy to be obtained.

The resin binder (B) used in the present invention is preferably a thermosetting resin. The thermosetting resin preferably includes at least one thermosetting resin selected from the group consisting of resol type phenolic resin, epoxy resin, and melamine resin, and at least one heat selected from the above group It is more preferable to be made of a curable resin. Among the above-mentioned thermosetting resins, resol type phenol resins are more preferable.
The metal paste composition of the present invention is a polymer type conductive paste in which a resin binder (B) is cured to form a conductive film. This conductivity is manifested by the contact of conductive particles, but in general, when metal particles containing copper are easily oxidized on the surface, when a metal paste composition using a thermoplastic resin as a binder is prepared, The conductivity of the obtained conductive film is low. However, when a thermosetting resin is used as a binder, it is known that high conductivity can be realized because metal particles are promoted to be in contact with each other by shrinkage at the time of curing and metal bonding of the particles is obtained. There is. Therefore, when the metal particles (A) contain particles made of copper particles or an alloy containing copper, the resin binder (B) preferably contains a resol type phenolic resin, and is more preferably made of a resol type phenolic resin preferable. When the resol type phenolic resin is used, surface oxidation of copper can be easily prevented, and the conductivity of the conductive film can be easily improved.

Specifically, as the resol type phenol resin, modified resol type phenol resin manufactured by adding various modifiers to phenols, unmodified resol type phenol resin produced from aldehydes, phenols and aldehydes Etc.
The molecular weight of the resol-type phenolic resin used in the present invention is not particularly limited, but from the viewpoint of solution viscosity at the time of solutionization, the mass average molecular weight is preferably 200 to 10,000, and more preferably 300 to 3,000.
Resol type phenolic resins are also available as commercial products. As an example of a commercial item of resol type phenol resin, RESITOP (registered trademark) PL-5208, PL-2407, and PL-6317 (made by Gun-ei Chemical Industry Co., Ltd.) can be mentioned.
One type of resol-type phenol resin may be used alone, or two or more types may be used in combination.

The epoxy resin is preferably used by adding a curing agent to the epoxy resin as the main component. As an epoxy resin, specifically, bisphenol A epoxy resin, bisphenol F epoxy resin, novolak epoxy resin, halogenated bisphenol epoxy resin, resorcinol epoxy resin, alicyclic epoxy resin, glycerin triether epoxy resin And polyolefin type epoxy resins, epoxidized soybean oil, limonene oxide, cyclopentadiene dioxide, vinylcyclohexene dioxide and the like. Moreover, the epoxy resin which has a glycidyl group is also preferable.
A common epoxy curing agent can be used as a curing agent for the epoxy resin. For example, aliphatic polyamines such as ethylenediamine, hexamethylenediamine and triethylenetetramine, aromatic amines such as m-xylenediamine, m-phenylenediamine and diaminophenylsulfone, dimethylaminocyclohexane, benzyldimethylamine, dimethylamino Examples thereof include tertiary amines such as methylphenol, acid anhydrides such as phthalic anhydride and hexahydrophthalic anhydride, and boron trifluoride amine complexes such as BF 3 -piperidine complex.

The epoxy resin can be appropriately produced according to a known method, but is also available as a commercial product. As an example of a commercial item of epoxy resin, Epototh (EPOTOHTO (registered trademark) YD-128, YD-127 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), jER (Jay Iar Al registered trademark) 828, 827, 871, 806 1256 (manufactured by Mitsubishi Chemical Corporation) can be mentioned.
An epoxy resin may be used individually by 1 type, and may use 2 or more types together.

The melamine resin in the present invention is a condensation reaction of melamine and formaldehyde to methylolate melamine (optionally further addition reaction), and then, if necessary, alkylate methylol group with alcohol (for example, methyl alcohol or butyl alcohol) Manufactured by
The melamine resin is a completely alkyl type in which the methylol group is almost completely alkylated, an imino type in which a large number of non-methylolated hydrogen groups remain, and a non-alkylated methylol group depending on the ratio of starting materials and the degree of alkylation. It is classified into the methylol type etc. with a high proportion of

The melamine resin in the present invention is preferably a fully alkylated melamine resin. This fully alkylated melamine resin does not contain a methylol group or an imino group, and has a methylol group which is completely etherified with a monohydric alcohol having usually 1 to 4 carbon atoms such as methanol, n-butanol, isobutanol and the like It is. Examples of commercially available products of melamine resin include Yuvan (registered trademark) 120 (manufactured by Mitsui Chemicals, Inc.), Nicarak (registered trademark) MW 30 (manufactured by Nippon Carbide Industries Co., Ltd.), and the like. One of these may be used, or two or more may be used in combination.
The same resin (guanamine resin) using benzoguanamine, acetoguanamine, and formoguanamine instead of melamine also has the same properties as the melamine resin, and thus the guanamine resin is also included in the melamine-based resin used in the present invention. Ru.

[Diluent (C)]
The metal paste composition of the present invention contains a diluent (C). 10-30 mass parts is preferable with respect to 100 mass parts of metal particles (A), and, as for content of the diluent (C) in a metal paste composition, 12-20 mass parts is more preferable.
In the metal paste composition of the present invention, the application of heat, light or the like causes the volatilization of the diluent and the shrinkage associated with the curing of the binder, and the shrinkage causes the metal particles to approach each other to develop conductivity. In order to express such conductivity, it is better that the amount of the diluent (C) in the metal paste composition is as small as possible. In addition, with regard to solder wettability, as the amount of the diluent (C) present on the surface is smaller, formation of solder alloy on metal particles is more likely to proceed. On the other hand, the amount of the diluent (C) is preferably in the above range because the amount of the diluent (C) is preferably a certain amount or more from the viewpoint of the coating property on the substrate.

Examples of the diluent (C) include ether alcohols, non-ether alcohols, esters, ketones, terpenes, and other hydrocarbons.
As ether alcohols, diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-isopropyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol dimethyl ether, ethylene Glycol methyl ethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether Seteto, diethylene glycol monobutyl ether acetate, ethylene glycol monomethyl ether, diethylene glycol monoethyl ether acetate, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and propylene glycol monomethyl ether, and the like. In particular, using diethylene glycol monoethyl ether and diethylene glycol monoethyl ether acetate is preferable in terms of conductivity and coatability to a substrate.

Examples of non-ether alcohols include methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, and triethylene glycol.
Esters include ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxy propionate, ethyl ethoxy propionate, diethyl oxalate, and diethyl malonate.
As ketones, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and the like can be mentioned.
Terpenes include turpentine oil, terpineol, borneol, α-pinene and the like. In particular, using terpineol is preferable in terms of conductivity and coatability to a substrate.
Other hydrocarbons include tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, diacetone alcohol, propylene carbonate and the like. It can be mentioned.
As the diluent (C), any one of these may be used, or two or more may be mixed and used. In particular, it is preferable to use one or more selected from ether alcohols or terpenes.
The metal paste composition of the present invention is a chelating agent, an antioxidant, a leveling agent, a viscosity modifier, and a dispersing agent, if necessary, in addition to (A) to (C), as long as the effects of the present invention are not impaired. Various known additives such as a curing agent and a foaming agent can be suitably contained. Moreover, the thing containing the impurity which can be mixed in unavoidably from the apparatus of a raw material component, a manufacturing process, etc. is also within the scope of the present invention.

<< Method of producing metal paste composition >>
The metal paste composition of the present invention can be produced by mixing (A) to (C) and, if desired, other additives using a kneading (mixing) apparatus. As a kneading apparatus, a three-roll kneader can be used. The kneading temperature may be in the range of 10 to 60 ° C., and the number of times of kneading may be such that the particles can be uniformly dispersed in the paste. The order of addition (mixing) of (A) to (C) may be any order, and batch addition and kneading may be performed.

<< Solder adhesion metal paste conductive film and its manufacturing method >>
The manufacturing method of the solder adhesion metal paste conductive film of the present invention is
<Step 1> A step of applying a metal paste composition containing a metal particle (A), a resin binder (B), and a diluent (C) to a substrate to form a coated film of the metal paste composition,
<Step 2> A step of semi-curing the coating film of the metal paste composition by heating to form a metal paste conductive film, <Step 3> a step of applying a solder paste on the metal paste conductive film, and <Step 4> A step of melting the solder paste by heating;
Have.

<Step 1>
Step 1 is a step of applying a metal paste composition containing metal particles (A), a resin binder (B) and a diluent (C) to a substrate to form a coated film of the metal paste composition.
The metal paste composition is applied to the substrate in the desired pattern. As a method of applying the metal paste composition, a desired method such as a casting method, gravure printing, screen printing, coating using a coater, spin coating, or the like can be employed.
The material of the substrate is not particularly limited, but it is preferable to have heat resistance to heat applied during the process, and examples of the material of such a substrate include polyimide (PI), polyamide imide (PAI), polyethylene Examples include terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyether sulfone (PES), fluorine resin, liquid crystal polymer, ceramics, glass, metal and the like.

<Step 2>
Step 2 is a step of semi-curing the coating film of the metal paste composition formed in step 1 by heating to form a metal paste conductive film.
The coating film is heated to cause thermal contraction of the resin binder (B) contained in the coating film or volume contraction due to evaporation of the diluent (C), and the metal particles (A) adhere to each other to form a conductive path. It becomes a metal paste conductive film. In the present invention, in step 2, the liquid metal paste composition is semi-cured without being completely cured. Here, “semi-hardening” means that the degree of progress of hardening of the conductive film (hereinafter also referred to as a curing reaction rate) determined from the calorific value measured by a differential scanning calorimeter (DSC) described later is 3% to 20%. I say the state.

If the curing reaction rate of the obtained conductive film is less than 3%, the degree of progress of curing is too low, and the flux and the solder alloy penetrate too much into the conductive film, and the amount of solder wetted to the surface is extremely reduced. Not suitable because it can not ensure solder wettability. When the curing reaction rate of the obtained conductive film is larger than 20%, the melted solder is repelled and it becomes difficult to manufacture the solder-adhered metal paste conductive film. This is thought to be because if the curing reaction rate is greater than 20%, three-dimensional crosslinking of the resin binder proceeds to form a strong network and the flux component in the solder paste does not easily penetrate into the conductive film. Be
In addition, the curing reaction rate of the above-mentioned metal paste composition measured by DSC is a sample collected from an uncured metal paste composition (uncured sample) and a sample collected from a heated metal paste composition (measurement) For each sample, DSC is performed to determine the calorific value of each sample, and the calorific value (total calorific value) of the uncured sample is H ₀ and the calorific value of the measurement sample (residual calorific value) is H ₁ as follows: It is a value calculated by equation (1).
Curing reaction rate (%) = {(H ₀ −H ₁ ) / H ₀ ) × 100 (1)
The conductive film having a hardening reaction rate of 3% to 20% has low crosslink density and low glass transition temperature, so it becomes soft in the low temperature region where the flux component in the solder paste applied on the conductive film is fluidized. The flux component can easily penetrate into the conductive film. Thereby, the oxide film on the surface of the metal particle is removed, alloy formation with the solder is promoted, and the solder wettability is improved.
The curing reaction rate is preferably 4 to 18%, and more preferably 4 to 9%, from the viewpoint of further improving the solder wettability.

In order to semi-cure the coating film of the metal paste composition, it is necessary to control the heating temperature and heating time, and the heating temperature is 70 ° C. to 130 ° C., the heating time is 1 minute to 20 minutes, and the temperature time product is 100. It is preferable that it is the range of -1500 degreeC * min. More preferably, the heating temperature is 75 ° C to 125 ° C, the heating time is 3 minutes to 20 minutes, and the temperature time product is 400 to 1300 ° C × minutes.
It is preferable to use a hot plate or a convection oven as a heating device.

<Step 3>
Process 3 is a process of applying a solder paste on the metal paste conductive film formed in process 2.
The method of applying the solder paste is not particularly limited, but a screen printing method using a metal mask is generally used. The applied film thickness of the solder paste is preferably in the range of 100 μm to 500 μm from the viewpoint of the printability of the solder paste and the wettability at the time of melting the solder.
Although it does not restrict | limit especially as a solder paste, What contains a solder particle and a flux can be used. The flux usually contains a resin, an activator, a thixo agent, a solvent and the like.
Although it does not restrict | limit especially as a solder particle, It is preferable to use the solder particle which melt | dissolves in the temperature range (for example, 250 degrees C or less) which the base material and conductive film of this invention can endure.

The solder particles used for the solder paste may be composed of Sn alone, or may be composed of an alloy of a lead-free solder alloy mainly composed of Sn, or composed of an Sn-Pb solder alloy. However, lead-free solder pastes are preferred as they are being transferred to lead-free solder pastes in consideration of environmental impact in recent years.
Commercially available lead-free solder pastes include E508 RMA (manufactured by Kojima Solder Manufacturing Co., Ltd., solder particle composition: Sn 96.5 / Ag 3.0 / Cu 0.5, melting point about 220 ° C.), TLF-204-171 (trade company Tamura Seisakusho, solder particle composition: Sn 96.5 / Ag3.0 / Cu 0.5, melting point about 220 ° C., SAM 10-401-27 (Tamura Seisakusho Co., Ltd., solder particle composition: Sn 42 / Bi 58, melting point about 160 ° C. And the like.

<Step 4>
Step 4 is a step of melting the solder paste applied on the metal paste conductive film in step 3 by heating. By this process, the melted solder particles (solder) and the metal paste conductive film are joined, and a solder-adhered metal paste conductive film can be obtained.
The heating conditions in this step are not particularly limited as long as the conductive film or the base material can withstand and the solder can be melted, but from the viewpoint of solder wettability, the temperature is 20 ° C. higher than the melting point of the solder particles. It is preferable to heat at a temperature higher than the above. It is preferable to use a hot plate or a reflow furnace as the heating device.

A series of bonding methods in which a solder paste is applied onto a metal material such as a metal paste conductive film, and the applied solder paste is heated and melted to join the solder paste are called reflow.
It is preferable to carry out reflow through (1) a temperature raising step, (2) a preheating step, and (3) a multistep heating step including a solder melting step in order to secure the durability of the joint and the like.
In the temperature raising step, as the temperature rises, the solvent evaporates, and at the same time, the resin in the solder paste, the thixo agent, etc. become soft, and the components in the paste become uniform. The heating rate is preferably 0.3 to 5 ° C./second. When the temperature is 0.3 ° C./sec or more, the productivity is enhanced, which is advantageous in cost. If the temperature is 5 ° C./sec or less, the solvent is easily evaporated, and the viscosity of the paste itself does not decrease significantly, so heat dripping can be prevented quickly, and eventually, defects such as side balls and bridges are hardly caused. Become. The temperature rise temperature is more preferably 0.5 to 3 ° C./second.

In the preheating process, the solvent is completely volatilized, heat is uniformly supplied to the entire substrate, the flux becomes soft like a liquid, and the solder powder is uniformly wrapped to prevent reoxidation.
As the temperature rises, a flux containing an activator, a resin and the like is activated, and the oxide particles are started to be removed from the solder particles and the surface to be joined. In the present invention, since the conductive film to be joined is in a soft state during curing, the flux penetrates into the conductive film and easily acts on the surface of the metal particles (A).
In the solder melting process, as the solder particles reach the melting point and melt, the oxide film is removed by the flux and soldering starts. The solder is completely melted and joined by heating for 30 to 100 seconds at a temperature higher than the melting point of the used solder particles, preferably 20 ° C. or more higher than the melting point, in the solder melting step.

  After the solder melting step, if necessary, a reheating step may be provided in which the hardening of the metal paste conductive film is advanced by heating. Thereby, the strength of the metal paste conductive film can be improved. The heating temperature in the step is preferably 70 ° C. or more and less than the melting point of the solder particles, and the upper limit of the heating temperature is more preferably 20 ° C. lower than the melting point of the solder particles. The heating time is preferably 300 to 1800 seconds. The heating can be performed using a known heating means such as an oven or a hot plate.

Hereinafter, the embodiments of the present invention will be more specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.
The material, measuring method, processing method and evaluation method of the metal paste composition used in each example and comparative example are shown below.
<Used Metal Particles (A)>
The following three types (A1) to (A3) were used as metal particles (A).
(A1): Surface treatment 1400 YP (flat plate type copper particles, average particle diameter D50; 5.8 μm, manufactured by Mitsui Mining & Smelting Co., Ltd.).
(A2): FCC-TB (tree-like copper particles, average particle diameter D50; 7.0 μm, manufactured by Fukuda Metal Foil & Powder Co., Ltd.).
(A3): Ag coated Cu powder EM (spherical silver coated copper particles, average particle diameter D50; 2.0 μm, manufactured by Dowa Electronics Corporation).

In the above (A1), the surface treatment was performed by the method described in the following steps (A) to (F).
[Step (A)]
An ammonium chloride-acetic acid aqueous solution was prepared in which 5 g of ammonium chloride and 5 g of acetic acid were dissolved in 100 g of water.
50 g of copper particles 1400 YP were added to the aqueous ammonium chloride-acetic acid solution and stirred at 30 ° C. for 60 minutes under nitrogen bubbling. Stirring was performed at a rotational speed of 150 rpm using a mechanical stirrer. Hereinafter, stirring was performed at the same rotation speed using the same stirring device.
After completion of the stirring, copper chloride-adhered copper particles were separated by filtration under reduced pressure using a 5 C filter paper Kamayama funnel, and subsequently, the copper chloride-adhered copper particles were washed twice with 150 g of isopropanol on the Kasayama funnel.
[Step (B)]
The washed copper chloride-adhered copper particles were added to 250 g of a 40% by mass aqueous solution of diethylenetriamine, and heated and stirred at 60 ° C. for 60 minutes while bubbling nitrogen.
[Step (C)]
The stirring was stopped and after standing for 15 minutes, about 200 g of the supernatant was withdrawn and removed. Subsequently, 200 g of isopropanol was added to the precipitate as a washing solvent, and the mixture was stirred at 30 ° C. for 3 minutes. The stirring was stopped and after standing for 15 minutes, about 200 g of the supernatant was withdrawn and removed to obtain Intermediate 1.
[Step (D)]
After 250 g of an isopropanol solution of 2% by mass of lauric acid was added to Intermediate 1, the mixture was stirred at 30 ° C. for 30 minutes.
[Step (E)]
After stopping the stirring, the isopropanol solution of lauric acid was removed by vacuum filtration to obtain Intermediate 2. Vacuum filtration was carried out by depressurizing a 5 C filter paper funnel with a diaphragm pump.
[Step (F)]
The intermediate 2 was dried under reduced pressure at 25 ° C. for 3 hours to obtain a surface treatment 1400 YP. Vacuum drying was performed by placing Intermediate 2 in a vacuum oven and depressurizing the oven with an oil pump.

<Used resin binder (B)>
The following three types of (B1), (B2) and (B3) containing solutions were used as a resin binder (B).
(B1): Resol type phenol resin PL-5208 [solid content 58.5 mass%, diluent: diethylene glycol monoethyl ether, manufactured by Gunei Chemical Industry Co., Ltd.] was used. The diluent diethylene glycol monoethyl ether was part of the diluent (C).
(B2): Resol type phenol resin PL-2407 [solid content 59.4 mass%, diluent: methyl alcohol, manufactured by Gunei Chemical Industry Co., Ltd.] was used. The diluent methyl alcohol was part of the diluent (C).
(B3): A homopolymer (weight-average molecular weight of 9,500) solution of vinylphenol [a 50.0 mass% diethylene glycol monoethyl ether acetate solution of Marca Linker S-4P, manufactured by Maruzen Petrochemical Co., Ltd.] was used. The diluent diethylene glycol monoethyl ether was part of the diluent (C).

<Diluent used (C)>
The following three types were used as a diluent (C).
(C1): Diethylene glycol monoethyl ether [diluent of (B1)]
(C2): methyl alcohol [diluent of (B2)]
(C3): Diethylene glycol monoethyl ether acetate [diluent of (B3)]

<Used Additive (D)>
The following five types were used as (D).
(D1): 1,4-phenylenediamine (D2): N, N′-bis (salicylidene) ethylenediamine (D3): KBM-603 [N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, Shin-Etsu Made by silicone company]
(D4): KBM-403 [3-glycidoxypropyl trimethoxysilane, manufactured by Shin-Etsu Silicone Co., Ltd.]
(D5): Tris (2-ethylhexyl) phosphate

Example 1-1
<Manufacture of metal paste composition>
(A1) 100 g, (B1) 26.5 g [(B); 15.5 g, (C1); 11.0 g], (D1) 0.2 g, and (D2) 1.9 g were mixed. Next, primary kneading was performed using a planetary mixer [ARV-310, manufactured by Shinky Co., Ltd.] for 30 seconds at a rotational speed of 1500 rpm at room temperature.
Next, secondary kneading was performed using a three-roll mill [EXAKT-M80S, manufactured by Nagase Screen Printing Laboratory Co., Ltd.] at room temperature and a distance between rolls of 5 μm by passing 5 times.
Next, 1.5 g of (C3) is added to the kneaded material obtained by the second kneading, and stirring is performed for 90 seconds at a rotational speed of 1000 rpm under room temperature and vacuum conditions using a planetary mixer to defoam and knead the metal. A paste composition was produced.
In addition, the blend ratio of each component in the metal paste composition is shown in Table 1.

Example (1-2 to 1-9)
A metal paste composition was produced in the same manner as in Example 1-1 except that the blending ratio of each component was as shown in Table 1.

<Formation of conductive film>
(Example 2-1)
The metal paste composition obtained in Example 1-1 was coated on a glass substrate in a shape of width × length × thickness = 10 mm × 30 mm × 30 μm using a metal mask. The electrically conductive film was produced by heating the glass substrate which apply | coated the metal paste composition with a hotplate at 80 degreeC for 10 minutes.

<Formation of solder adhesion metal paste conductive film>
Solder paste (TLF-204-171A, Sn-Ag-Cu-based, melting point: about 220 ° C, Tamura Seisakusho) on the obtained conductive film, using a metal mask, width x length x thickness 2 mm A pattern of 2 mm × 200 μm was applied at 10 mm intervals so that two patterns were formed. A glass substrate sample in which solder paste is applied to the surface of a conductive film is heated with a hot plate in the following profiles (1) to (4) to melt the solder, and a solder adhesion metal paste conductive film is produced. did.
(1) 25 ° C → 160 ° C (heating rate 0.5 ° C / sec)
(2) 160 ° C. × 60 seconds (3) 160 ° C. → 240 ° C. (heating rate 0.5 ° C./sec)
(4) 240 ° C × 30 seconds

(Examples 2-2 to 2-14, comparative examples 2-1 to 2-3)
A solder adhesion metal paste conductive film was produced in the same manner as in Example 2-1 except that the metal paste composition used and the curing conditions (conductive film production conditions) of the metal paste composition were as shown in Table 2. .

<Evaluation method of curing reaction rate>
In Examples 2-1 to 2-14 and Comparative Examples 2-1 to 2-3, the metal paste conductive film before applying the solder was scraped off, and the uncured metal paste composition not heated Then, 1.5 mg of each was put in an aluminum sample pan with a diameter of 5 mm for DSC6200 (manufactured by Seiko Instruments Inc.), and the sample was covered to prepare a sample for evaluation of the curing reaction rate. Subsequently, differential scanning calorimetry (DSC) measurement of each sample is performed, and the calorific value of the uncured metal paste composition is the total calorific value H ₀ , and the calorific value of the scraped conductive film is the residual calorific value H _1. The curing reaction rate was calculated by equation (1). The calorific value was calculated from the peak area of 100 ° C to 250 ° C.
Curing reaction rate (%) = {(H ₀ −H ₁ ) / H ₀ ) × 100 (1)
[Measurement condition]
· Heating rate 10 ° C / min (25 ° C to 300 ° C)
・ N ₂ gas 100mL / min
・ Sample weight about 1.5 mg

  FIG. 1 shows the case where the metal paste composition of Example 1-1 is uncured, thermally cured at 120 ° C. × 5 min (Example 2-5), 150 ° C. × 15 min (Comparative Example 2-3), and completely It is a DSC chart figure of the conductive film which hardened | cured (hardened at 200 degreeC x 90 minutes).

<Solder wettability evaluation>
The solder wettability of the obtained conductive film was evaluated by the ratio of the area at the time of solder paste application and the area of the portion actually wetted by the solder after melting of the solder paste. The solder wettability is good when the area of the part that is wet with solder is 90% or more (○ in the table), and the solder wettability is poor when the area of the part that is wet with solder is lower than 90% In the table, it was evaluated as x). The observed image of the solder adhesion metal paste conductive film when the solder wettability is ((Example 2-5) is shown in FIG. 2, and the solder adhesion metal paste when the solder wettability is x (Comparative Example 2-3) An observation image of the conductive film is shown in FIG.

<Resistance between soldered parts>
The conductivity between the solder-coated parts of the obtained solder adhesion metal paste conductive film was evaluated by the resistance value measured using a digital multitester (PC7000, manufactured by Sanwa Denki Keiki Co., Ltd.). In the table ※ ※ O. L. Indicates that the value is higher than the measurement limit (50 MΩ).
The evaluation results of each example and comparative example are shown in Table 2.

Examples 2-1 to 2-14 use the metal paste compositions prepared in Examples 1-1 to 1-9, and change the curing conditions (temperature × time) to prepare solders of conductive films prepared. It is a wettability evaluation result, and on these conditions, the favorable electrically conductive film of solder wettability was able to be formed.
On the other hand, in the case of Comparative Example 2-1, although it is a solder wettability evaluation result of the electrically conductive film produced on the heating conditions of 80 degreeC x 1 minute using the metal paste composition of Example 1-1, solder wettability is It was x. It is considered that this is because the curing reaction rate is too low, the flux and the solder alloy penetrate too much into the conductive film, and the amount of solder wetted to the surface of the conductive film is extremely reduced and the solderability can not be ensured.
In the case of Comparative Examples 2-2 and 2-3, the solder wettability evaluation of the conductive film produced under the heating conditions of 100 ° C. × 20 minutes and 150 ° C. × 15 minutes using the metal paste composition of Example 1-1 Although it is a result, solder wettability was x. It is considered that this is because the resin binder (B) is sufficiently cured by heat, the crosslink density is increased, and the flux component contained in the solder paste hardly penetrates into the conductive film.

Claims (7)

Applying a metal paste composition containing metal particles (A), a resin binder (B), and a diluent (C) to a substrate to form a coated film of the metal paste composition;
Semi-curing the coating film of the metal paste composition by heating to form a metal paste conductive film;
Applying a solder paste on the metal paste conductive film;
And a step of melting the solder paste by heating.   The metal particles (A) in the metal paste composition are selected from the group consisting of gold, silver, copper, platinum, palladium, rhodium, nickel, zinc, tin, and aluminum, and an alloy containing a metal selected therefrom The manufacturing method of the solder adhesion metal paste conductive film of Claim 1 which is at least 1 type of particle | grain.   The manufacturing method of the solder adhesion metal paste conductive film of Claim 1 or 2 in which the metal particle (A) in the said metal paste composition contains the particle which consists of an alloy containing a copper particle or copper.   The resin binder (B) in the said metal paste composition contains at least 1 or more types of thermosetting resin selected from the group which consists of a resol type phenol resin, an epoxy resin, and a melamine resin. The manufacturing method of the solder adhesion metal paste conductive film as described in.   The manufacturing method of the solder adhesion metal paste conductive film in any one of Claims 1-4 in which the resin binder (B) in the said metal paste composition contains a resol type phenol resin.   The manufacturing method of the solder adhesion metal paste conductive film in any one of Claims 1-5 in which the metal particle (A) in the said metal paste composition contains surface coating metal particle. In the metal paste composition, the metal particles (A) are composed of surface-coated copper particles, and the surface-coated copper particles are bonded to the surface of the copper particles by chemical bonding and / or physical bonding with copper on the surface of the copper particles. And a first coated layer of an amine compound represented by the formula (1), and an aliphatic monocarboxylic acid having 8 to 20 carbon atoms bonded to the amine compound by a chemical bond on the first coated layer. A surface-coated copper particle having a second coating layer, wherein the resin binder (B) is a resol-type phenolic resin, and 10 to 30 mass of the resin binder (B) relative to 100 mass parts of the metal particle (A) The method for producing a soldered metal paste conductive film according to any one of claims 1 to 6, wherein the part (10) to 30 parts by mass of the diluent (C) is contained.

[In the formula (1), m is an integer of 0 to 3, n is an integer of 0 to 2, and when n = 0, m is any of 0 to 3 and n = 1 or n = 2 m is any one of 1 to 3. ]