JP5509283B2 - Heat-sinterable metal fine particle production method, paste-like metal fine particle composition, solid metal or solid metal alloy production method, metal member joining method, printed wiring board production method, and electrical circuit connection bump production Method - Google Patents

Description

The present invention comprises a method for producing a heat-sinterable metal fine particle coated with a polymer dispersant; a heat-sinterable metal fine particle coated with a polymer dispersant, a volatile dispersion medium, and a low molecular weight carboxylic acid, Paste-like metal fine particle composition which becomes a solid metal having excellent strength, electrical conductivity and thermal conductivity when sintered by heating; heat-sinterable metal fine particles coated with a polymer dispersant and heat-sinterability Paste metal fine particle composition consisting of metal particles, volatile dispersion medium and low molecular weight carboxylic acid, which is sintered by heating to form solid metal or solid metal alloy with excellent strength, electrical conductivity and thermal conductivity A solid metal or solid metal alloy production method from the paste metal fine particle composition; a metal member joining method using the paste metal fine particle composition; and the paste metal fine particle composition Printed wiring board manufacturing method of using; method of manufacturing an electrical circuit connection bumps of using and the pasty metal particle composition relates.

Conductive paste made by dispersing silver powder in thermosetting resin composition is cured by heating to form a conductive film, so that conductive circuit formation on printed circuit boards, resistors, capacitors, etc. Electrode formation of various electronic parts and display elements, formation of a conductive film for electromagnetic wave shielding, adhesion of chip parts such as capacitors, resistors, diodes, memories and arithmetic elements (CPUs) to substrates, solar cell electrodes, In particular, it is used for forming electrodes of solar cells that cannot be processed at high temperature using amorphous silicon semiconductors, forming external electrodes of chip-type ceramic electronic components such as multilayer ceramic capacitors, multilayer ceramic inductors, multilayer ceramic actuators, and the like.
In recent years, the amount of heat generated from chip parts has increased due to the high performance of chip parts, and it is required to improve the thermal conductivity as well as the electrical conductivity. When trying to improve the thermal conductivity, there is a problem that the viscosity of the paste increases and the workability is remarkably lowered.

In order to solve such a problem, the present inventors heated the paste-like silver particle composition composed of silver powder and a volatile dispersion medium, and the volatile dispersion medium volatilized and the silver powder was sintered. It became solid silver having extremely high electrical conductivity and thermal conductivity, and was found to be useful for joining metallic members and forming conductive circuits (Patent Document 1 and Patent Document 2).
However, due to heat resistance limitations of electronic devices, electronic components, chip components, and the materials constituting them, it is required that the paste-like composition is sintered at low temperatures and has adhesiveness to the substrate. Cases are increasing.
However, especially when sintered at a low temperature, the curability and adhesiveness are not sufficiently developed, and this is caused by the coating of silver particles such as higher fatty acids and higher fatty acid salts used for the purpose of preventing aggregation of silver particles. I noticed a problem with the drug. Therefore, a method for producing heat-sinterable silver particles that can be sintered at a low temperature by replacing these higher fatty acids and higher fatty acid salts with lower fatty acids or lower fatty acid salts, and the heat sintering A paste-like silver particle composition comprising conductive silver particles and a volatile dispersion medium, heating the paste-like silver particle composition, volatilizing the volatile dispersion medium and sintering the silver powder; It became solid silver having thermal conductivity, and was found to be useful for joining metal members and forming conductive circuits (Patent Document 3).
However, there is a problem that the adhesive strength is insufficient when the paste-like silver particle composition comprising the heat-sinterable silver particles and the volatile dispersion medium is used for joining metal members.

Since silver used in the paste-like silver particle composition, particularly nano-sized silver, is a fine particle, its surface is coated with an organic substance in order to prevent aggregation of the silver particles. In patent document 4, in order to prevent aggregation of silver powder, the silver powder coat | covered with the higher fatty acid is manufactured by making a higher fatty acid coexist in a silver powder production | generation process. Specifically, a reducing agent such as formalin and sodium hydroxide and a higher fatty acid such as stearic acid, oleic acid and palmitic acid are added to an aqueous silver nitrate solution and stirred, and then the silver powder coated with these higher fatty acids is separated. ing.
However, since the silver particles are coated with higher fatty acids that are difficult to remove by sintering at a low temperature, a paste-like silver particle composition comprising the silver particles and a volatile dispersion medium is used for joining metal members. In this case, there is a problem that the adhesive strength is insufficient.

In Patent Document 5, silver particles coated with a higher fatty acid salt are produced by making a higher fatty acid salt (eg, sodium oleate) coexist when reducing silver oxide to produce silver particles. Higher fatty acid salt-coated silver particles are flaked with a ball mill.
In Patent Document 6, a surfactant (eg, polyethylene glycol dioleate) and / or a higher fatty acid (eg, oleic acid, stearic acid, myristic acid) is added when the silver particles are flaked with a ball mill.
However, since the flaky silver particles are coated with higher fatty acids and / or higher fatty acid salts that are difficult to remove at low temperatures, the paste-like silver particle composition comprising the silver particles and a volatile dispersion medium is used as a metal member. When used for joining, there is a problem that the adhesive strength is insufficient.

Patent Document 7 states that “polyvalent carboxylic acid (eg, adipic acid, succinic acid, diglycolic acid, glutaric acid or maleic acid) is coated in an amount of 0.01% by mass to 0.5% by mass with respect to the material silver powder. Granular silver powder ”,“ Polyvalent carboxylic acid is added in an amount of 0.01% to 0.5% by mass with respect to the material silver powder in a state dissolved in a solvent, and the material silver powder to which the polyvalent carboxylic acid is added is pulverized and disintegrated. A method for producing granular silver powder, in which the polyvalent carboxylic acid is mixed with the material silver powder while being pulverized and pulverized by a crusher, and the solvent is removed to obtain granular silver powder "and" resin containing the granular silver powder " A “curable conductive paste” is disclosed. Only the silver powder produced by the wet reduction method is described as the material silver powder. However, if the surface of the silver powder produced in the manufacturing process by the wet reduction method is not immediately coated with a fatty acid, a large amount of silver powder having a large particle size is generated, and the resulting particle size distribution of the silver powder becomes unstable. There is a problem that the yield decreases. Furthermore, the above production method has a problem that it is difficult to produce silver powder having a small particle size. Moreover, when polyhydric carboxylic acid exceeds 0.5 mass%, there exists a problem which the electroconductivity of resin curable conductive paste falls. Further, the volume resistivity of the cured product of the resin curable conductive paste exceeds 1 × 10 ⁻⁵ Ω · cm, and there is a problem that the conductivity is low.

Patent Document 8 discloses an organic substance having an average primary particle diameter of 1 to 200 nm and having 8 or less carbon atoms (eg, an example) in order to make it possible to form a bonded body that exhibits practical bonding strength even in a nitrogen environment. , Hexanoic acid, heptanoic acid, adipic acid, sorbic acid, malonic acid), silver nanoparticles coated with a flux component (eg, oxydiacetic acid) having two or more carboxyl groups, and a dispersion medium are disclosed. ing. However, simply by adding a flux component having two or more carboxyl groups to the paste-like bonding material containing a solvent, an organic substance originally covering the surface of the silver nanoparticles is contained in the bonding material. Since it remains, there is a problem that bonding by sintering at a low temperature is not sufficient.

International Publication No. 2006/126614 International Publication No. 2007/034833 JP 2009-289745 A JP 54-121270 A JP 2001-49309 A JP 2003-55701 A JP 2011-140714 A JP 2011-240406 A

The inventors of the present invention have a paste-like metal fine particle composition that does not have the above problems, that is, a solid metal that is sintered at a relatively low temperature and has excellent adhesion strength, hardness, electrical conductivity, and thermal conductivity. As a result of diligent research to develop a paste-like fine metal particle composition, the organic fine particles coated with an organic substance having a polar group were replaced with a polymer dispersant having an acidic functional group and a basic functional group. It has been found that this is effective, and the present invention has been completed.

The object of the present invention is to form a paste-like metal that is easily sintered at a relatively low temperature and becomes a solid metal having excellent adhesion strength, hardness, electrical conductivity and thermal conductivity when heated. Method for producing heat-sinterable metal fine particles as a raw material for producing a metal fine particle composition; when heated, heat-sinterable metal fine particles or heat-sinterable metal fine particles and heat-sinterable metal particles are at a relatively low temperature Paste metal fine particle composition that is easily sintered and becomes a solid metal or solid metal alloy having excellent adhesion strength, hardness, electrical conductivity and thermal conductivity; A method for producing a solid metal or solid metal alloy having excellent electrical and thermal conductivity; the paste-like fine metal particle composition is used to firmly join a metal member with good electrical and thermal conductivity Method: Adhesion to substrate and electricity An object of the present invention is to provide a method for producing a printed wiring board having metal wiring excellent in air conductivity and heat conductivity; and a method for producing a bump for connecting an electric circuit excellent in electric conductivity and heat conductivity.

This purpose is
“[1] The organic material of heat-sinterable metal fine particles having an average particle diameter of 0.005 μm to 0.2 μm and the surface coated with an organic material having 5 to 24 carbon atoms having a polar group is acidic. A heating agent characterized in that a polymer dispersant having a functional group and a basic functional group is substituted until no exothermic peak due to thermal decomposition of the organic substance of the heat-sinterable metal fine particles is detected in differential thermal analysis. Method for producing sinterable metal fine particles.
[2] The method for producing heat-sinterable metal fine particles according to [1], wherein the polymer dispersant has an acid value and an amine value of 5 to 300 mgKOH / g, respectively.
[3] The acidic functional group of the polymer dispersant is a carboxyl group, a phosphoric acid group or an acidic phosphoric ester group, and the basic functional group is an amino group or an ammonium base, [1] or [2] The method for producing heat-sinterable metal fine particles according to [2].
[3-1] A part of the carboxyl group, phosphate group or acidic phosphate group in the molecule is salified and / or a part of the amino group in the molecule is salified The method for producing heat-sinterable metal fine particles according to [3].
[3-2] The chlorination of the carboxyl group, phosphate group or acidic phosphate group is ammonium chloride, alkylammonium chloride or aminoamide chloride, and the chlorination of the amino group is carboxylate, phosphate or acidic phosphate The method for producing heat-sinterable metal fine particles according to [3-1], which is ester chloride.
[4] The method for producing heat-sinterable metal fine particles according to any one of [1] to [3], wherein the polymer dispersant is composed of a synthetic polymer.
[4-1] The method for producing heat-sinterable metal fine particles according to any one of [3-1] and [3-2], wherein the polymer dispersant is composed of a synthetic polymer.
[5] The method for producing heat-sinterable metal fine particles according to [4], wherein the synthetic polymer is a vinyl polymer or a condensation polymer.
[5-1] The method for producing heat-sinterable metal fine particles according to [4-1], wherein the synthetic polymer is a vinyl polymer or a condensation polymer.
[6] The heat-sinterable metal fine particles according to any one of [1] to [5], wherein the heat-sinterable metal fine particles are heat-sinterable silver fine particles or heat-sinterable copper fine particles Production method.
[7] The heat-sinterable metal fine particles are spherical, granular or flaky, and the organic substance having 5 to 24 carbon atoms having a polar group is an aliphatic carboxylic acid, [6] The method for producing heat-sinterable metal fine particles according to any one of [6]. Is achieved.

This purpose is
“[8] (A) The organic material of heat-sinterable metal fine particles having an average particle diameter of 0.005 μm to 0.2 μm and having a surface coated with an organic material having 5 to 24 carbon atoms having a polar group The heat-sinterable metal was replaced with a polymer dispersant having an acidic functional group and a basic functional group until the exothermic peak due to decomposition of the organic matter of the heat-sinterable metal fine particles was not detected in the differential thermal analysis. It consists of fine particles, (B) a volatile dispersion medium having a boiling point of 70 ° C. to 300 ° C., and (C) a monovalent or divalent carboxylic acid having 2 to 10 carbon atoms. A paste-like fine metal particle composition, wherein B) is volatilized and the heat-sinterable fine metal particles (A) are sintered together.
[9] (A) The organic material of the heat-sinterable metal fine particles having an average particle diameter of 0.005 μm to 0.2 μm and having a surface coated with an organic material having 5 to 24 carbon atoms having a polar group. Heat-sinterable metal fine particles substituted with a polymer dispersant having an acidic functional group and a basic functional group until the exothermic peak due to decomposition of the organic matter of the heat-sinterable metal fine particles is not detected in differential thermal analysis (B) a volatile dispersion medium having a boiling point of 70 ° C. to 300 ° C., (C) a monovalent or divalent carboxylic acid having 2 to 10 carbon atoms, and (D) an average particle diameter of 0.2 μm. And the heat-sinterable metal particles having a diameter of 10 μm or less, the volatile dispersion medium (B) is volatilized by heating, and the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D) are sintered. A paste-like fine metal particle composition characterized by being bonded.
[10] The paste-like fine metal particle composition according to [8] or [9], wherein the polymer dispersant has an acid value and an amine value of 5 to 300 mgKOH / g, respectively.
[11] The polymer functional agent according to [10], wherein the acidic functional group of the polymer dispersant is a carboxyl group, a phosphoric acid group or an acidic phosphoric ester group, and the basic functional group is an amino group or an ammonium base. A paste-like fine metal particle composition.
[11-1] Characterized in that a part of the carboxyl group, phosphate group or acidic phosphate group in the molecule is salified and / or a part of the amino group in the molecule is salified. [11] The method for producing heat-sinterable metal fine particles according to [11].
[11-2] The chlorination of the carboxyl group, phosphate group or acidic phosphate group is ammonium chloride, alkylammonium chloride or aminoamide chloride, and the chlorination of the amino group is carboxylate, phosphate or acidic phosphate The paste-like fine metal particle composition according to [11-1], which is esterified.
[12] The paste-like fine metal particle composition according to any one of [8] to [11], wherein the polymer dispersant comprises a synthetic polymer.
[12-1] The paste-like fine metal particle composition according to any one of [11-1] and [11-2], wherein the polymer dispersant comprises a synthetic polymer.
[13] The sinterable fine metal particle composition according to [12], wherein the synthetic polymer is a vinyl polymer or a condensation polymer.
[13-1] The sinterable fine metal particle composition according to [12-1], wherein the synthetic polymer is a vinyl polymer or a condensation polymer.
[14] The paste-like metal according to any one of [8] to [13], wherein the heat-sinterable metal fine particles (A) are heat-sinterable silver fine particles or heat-sinterable copper fine particles Fine particle composition.
[14-1] The heat-sinterable metal fine particles (A) are heat-sinterable silver fine particles or heat-sinterable copper fine particles, [11-1], [11-2], [12 -1], [13-1] The paste-like fine metal particle composition according to any one of [13-1].
[14-2] Heat-sinterable metal particles (A) are heat-sinterable silver particles or heat-sinterable copper particles, and heat-sinterable metal particles (D) are heat-sinterable silver particles or heat-fired particles. The paste-like metal fine particle composition according to any one of [9] to [13], which is a cohesive copper particle.
[14-3] The heat-sinterable metal fine particles (A) are heat-sinterable silver fine particles or heat-sinterable copper fine particles, and the heat-sinterable metal particles (D) are heat-sinterable silver particles or heat-fired. The paste-like fine metal particle composition according to any one of [11-1], [11-2], [12-1], and [13-1], which is a caustic copper particle.
[15] The shape of the heat-sinterable metal fine particles (A) is spherical, granular or flaky, the organic substance having 5 to 24 carbon atoms having a polar group is an aliphatic carboxylic acid, and the heat-sinterable metal particles The paste-like fine metal particle composition according to any one of [8] to [14], wherein the shape of (D) is spherical, granular or flaky. Is achieved.

This purpose is
“The paste-like fine metal particle composition according to any one of [16] [8] to [15] is heated at 70 ° C. or higher and 300 ° C. or lower to volatilize the volatile dispersion medium (B) and heat-fired. Sintering fine metal particles (A) or heat-sinterable metal fine particles (A) and heat-sinterable metal particles (D) are sintered, and the volume resistivity after sintering is 1 × 10 ⁻⁵ Ω · cm or less. And having a thermal conductivity of 80 W / m · K or more, a method for producing a solid metal or solid metal alloy.
[16-1] The paste-like fine metal particle composition according to any one of [11-1], [11-2], [12-1], and [13-1] is heated at 70 ° C. or higher and 300 ° C. or lower. The volatile dispersion medium (B) is volatilized to sinter the heat-sinterable metal fine particles (A) or the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D). The production of a solid metal or solid metal alloy characterized by having a volume resistivity after sintering of 1 × 10 −5 Ω · cm or less and a thermal conductivity of 80 W / m · K or more. Method. Is achieved.

This purpose is
“[17] The paste-like metal fine particle composition according to any one of [8] to [15] is interposed between a plurality of metal members, and is heated at 70 ° C. or more and 300 ° C. or less to produce a volatile dispersion medium ( B) is volatilized to sinter the heat-sinterable metal fine particles (A) or the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D) to join a plurality of metal members. A method for joining metal members, characterized in that:
[17-1] The paste-like fine metal particle composition according to any one of [11-1], [11-2], [12-1], and [13-1] is interposed between a plurality of metal members. The volatile dispersion medium (B) is volatilized by heating at 70 ° C. or higher and 300 ° C. or lower, and the heat-sinterable metal fine particles (A) or the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles ( A method for joining metal members, characterized in that D) is sintered to join a plurality of metal members together.
[18] The method for joining metal members according to [17], wherein the metal member is a metal substrate or a metal part of an electronic component. Is achieved.

This purpose is
“[19] The paste-like fine metal particle composition according to any one of [8] to [15] is applied on a substrate coated with an adhesive and heated at 70 ° C. or more and 300 ° C. or less to volatilize. Volatilizing the dispersible dispersion medium (B) and sintering the heat-sinterable metal fine particles (A) together or the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D) to form a metal on the adhesive A method of manufacturing a printed wiring board, comprising forming a wiring or a metal alloy wiring.
[19-1] The paste-like fine metal particle composition according to any one of [11-1], [11-2], [12-1], and [13-1] is applied on a substrate coated with an adhesive. The volatile dispersion medium (B) is volatilized by heating to 70 ° C. or more and 300 ° C. or less, and the metal fine particles (A) or heat sinterable metal fine particles (A) and heat sinterable metal particles ( A method for producing a printed wiring board, comprising: sintering D) to form a metal wiring or a metal alloy wiring on an adhesive. Is achieved.

This purpose is
“[20] Apply the paste-like fine metal particle composition according to any one of [8] to [15] in a dot shape to an electric circuit connecting pad on a semiconductor element or an electric circuit connecting electrode on a substrate. Then, by heating at 70 ° C. or more and 300 ° C. or less, the volatile dispersion medium (B) is volatilized, and the heat-sinterable metal fine particles (A) or the heat-sinterable metal fine particles (A) and the heat-sinterable metal A method for producing a bump for connecting an electric circuit, comprising sintering particles (D) to form a metal bump or a metal alloy bump on a semiconductor element or a substrate.
[20-1] The paste-like fine metal particle composition according to any one of [11-1], [11-2], [12-1], and [13-1] is used for electrical circuit connection on a semiconductor element. The volatile dispersion medium (B) is volatilized by applying it in the form of dots on the pad part or the electrode part for electric circuit connection on the substrate and heating at 70 ° C. or more and 300 ° C. or less, thereby heat-sintering metal fine particles (A ) Sintering each other or heat-sinterable metal fine particles (A) and heat-sinterable metal particles (D) to form metal bumps or metal alloy bumps on a semiconductor element or substrate. A method of manufacturing a bump for connecting an electric circuit. Is achieved.

According to the method for producing a heat-sinterable metal fine particle of the present invention, an organic substance having 5 to 24 carbon atoms having a polar group covering the heat-sinterable metal fine particle is converted into an acidic functional group and a basic functional group. The heat-sinterable metal fine particles coated with the polymer dispersant having an acidic functional group and a basic functional group can be easily produced by substituting with the polymer dispersant.
In the paste-like metal fine particle composition of the present invention, the volatile dispersion medium (B) is volatilized by heating at a relatively low temperature, and particularly by heating at 70 ° C. or more and 300 ° C. or less, the heat-sinterable metal fine particles ( A) Solid metals or solids having excellent adhesion strength, hardness, electrical conductivity and thermal conductivity by sintering each other, or heat-sinterable metal fine particles (A) and heat-sinterable metal particles (D) Shape metal alloy.

According to the method for producing a solid metal or solid metal alloy of the present invention, the volatile dispersion medium (B) is volatilized by heating at a relatively low temperature, and in particular, heated by heating at 70 ° C. or more and 300 ° C. or less. Sinterable metal fine particles (A) or heat-sinterable metal fine particles (A) and heat-sinterable metal particles (D) sinter and have excellent adhesion strength, hardness, electrical conductivity and thermal conductivity. A solid metal or solid metal alloy can be produced.
According to the method for joining metal members of the present invention, the volatile dispersion medium (B) is volatilized by heating at a relatively low temperature, and particularly by heating at 70 ° C. to 300 ° C., the heat-sinterable metal fine particles (A) or heat-sinterable metal fine particles (A) and heat-sinterable metal particles (D) are sintered to firmly join a plurality of metal members with good electrical and thermal conductivity. Can do.

According to the method for producing a printed wiring board of the present invention, the volatile dispersion medium (B) is volatilized by heating at a relatively low temperature, and particularly by heating at 70 ° C. to 300 ° C., the heat-sinterable metal fine particles (A) or heat-sinterable metal fine particles (A) and heat-sinterable metal particles (D) sinter and have excellent wear resistance, adhesion to the substrate, electrical conductivity, and thermal conductivity A printed wiring board having metal wiring or metal alloy wiring can be manufactured. Further, a circuit board can be manufactured by mounting a chip or the like on the printed wiring board by the bonding method.

According to the method for manufacturing a bump for connecting an electric circuit of the present invention, a metal bump or a metal alloy bump excellent in electrical conductivity and thermal conductivity can be efficiently and easily formed on a semiconductor element or a substrate.

2 is a differential thermal analysis (temperature increase rate: 10 ° C./min) chart in air for silver fine particles before organic substance replacement in Example 1. FIG. 2 is a differential thermal analysis (temperature increase rate: 10 ° C./min) chart in air for silver fine particles after organic substance replacement in Example 1. FIG. 10 is a differential thermal analysis (temperature increase rate: 10 ° C./min) chart of the pasty silver fine particle composition containing no carboxylic acid in the air in Comparative Example 3. 6 is a differential thermal analysis (temperature increase rate: 10 ° C./min) chart in the air of a paste-like silver fine particle composition containing a carboxylic acid in Example 5. It is a top view of the test body A for adhesive strength measurement in an Example. A paste-like fine metal particle composition 2 is printed and applied on a silver substrate 1 with a metal mask, and after mounting the silver chip 3, it is heated to bond the silver substrate 1 and the silver chip 3 and measure the adhesive strength. . It is a side view of the XX line direction in FIG.

In the method for producing the heat-sinterable metal fine particles of the present invention, the average particle diameter is 0.005 μm to 0.2 μm, and the surface is coated with an organic substance having 5 to 24 carbon atoms having a polar group. Until the exothermic peak due to the decomposition of the organic substance of the heat-sinterable metal fine particle is not detected in the differential thermal analysis by using the polymer dispersion medium having an acidic functional group and a basic functional group. It is characterized by replacing. As a result of the replacement, heat-sinterable metal fine particles in which the surface of the heat-sinterable metal fine particles is coated with the polymer dispersant are produced.

The paste-like fine metal particle composition (I) of the present invention has (A) an average particle diameter of 0.005 μm to 0.2 μm, and its surface is coated with an organic substance having 5 to 24 carbon atoms having a polar group. In the differential thermal analysis, the exothermic peak due to the decomposition of the organic matter of the heat-sinterable metal fine particles is detected by using a polymer dispersant having an acidic functional group and a basic functional group. Heat-sinterable metal fine particles that are substituted until they are eliminated, (B) a volatile dispersion medium having a boiling point of 70 ° C. to 300 ° C., and (C) a monovalent or divalent carboxylic acid having 2 to 10 carbon atoms, It is characterized by being a paste-like metal fine particle composition in which the volatile dispersion medium (B) is volatilized by heating and the heat-sinterable metal fine particles (A) are sintered together.

The paste-like fine metal particle composition (II) of the present invention has (A) an average particle diameter of 0.005 μm to 0.2 μm, and the surface thereof is coated with an organic substance having 5 to 24 carbon atoms having a polar group. In the differential thermal analysis, the exothermic peak due to the decomposition of the organic matter of the heat-sinterable metal fine particles is detected by using a polymer dispersant having an acidic functional group and a basic functional group. Heat-sinterable metal fine particles that are substituted until they are eliminated, (B) a volatile dispersion medium having a boiling point of 70 ° C. to 300 ° C., and (C) a monovalent or divalent carboxylic acid having 2 to 10 carbon atoms, (D) Heat-sinterable metal particles having an average particle diameter of more than 0.2 μm and 10 μm or less, and the volatile dispersion medium (B) is volatilized by heating to heat-sinterable metal fine particles (A) and heat. Paste-like metal fine particles sintered by sinterable metal particles (D) It is a composition.

The heat-sinterable metal fine particles whose average particle diameter is 0.005 μm to 0.2 μm and whose surface is coated with an organic substance having 5 to 24 carbon atoms having a polar group are reduced silver, atomized silver, silver colloid Heat-sinterable silver fine particles such as silver alloy, surface silver coated powder, and heat-sinterable metal fine particles such as gold, palladium, copper, tin, and solder alloys are exemplified. Is preferred, followed by copper fine particles.
Examples of the shape of the heat-sinterable metal fine particles are spherical, needle-shaped, angular, dendritic, fibrous, flake-shaped (single), granular, irregular shape, and teardrop-shaped (see JIS Z2500: 2000) Furthermore, elliptical spherical, spongy, grape-like, spindle-like, spindle-like, hexagonal plate-like, columnar, rod-like, porous, lump-like, square-like, round-like are exemplified, but ease of manufacture and easy procurement From the viewpoint of properties, it is preferably spherical, granular and flaky.

The spherical shape referred to here is a shape that is almost a sphere (see JIS Z2500: 2000). The spherical shape is not necessarily required, and the ratio of the major axis (DL) to the minor axis (DS) of the particle (DL) / (DS) (sometimes referred to as spherical coefficient or sphericity) is 1.0 to 1. Those in the range of .2 are preferred.
Granular is not an irregular shape but a shape with almost equal dimensions (see JIS Z2500: 2000).

The flake shape (strip shape) is a plate-like shape (see JIS Z2500: 2000) and is also called a scale shape because it is a thin plate shape like a scale.

The aspect ratio of the flaky heat-sinterable metal fine particles referred to here is a value of [average length (μm) in the plane direction of particles] / [average thickness (μm) of particles], which is 2 to 200. Is preferably in the range of 5-50. In calculating the aspect ratio, the value of the average length in the planar direction is, for example, observed with a scanning electron microscope at a magnification of about 1000 to 10000 times, and 20 or more heat-sinterable metal fine particles in the observed image are observed. The length in the plane direction can be measured and obtained as the average value. The average thickness is determined by, for example, manufacturing a sample in which flaky heat-sinterable metal fine particles are hardened with a curable resin such as an epoxy resin, and the cross section of the sample is magnified 5000 to 20000 with a scanning electron microscope. By observing at a magnification of about twice, the thickness of 20 or more heat-sinterable metal fine particles in the observed image can be measured and obtained as an average value. No matter the shape, the particle size distribution is not limited.

In the method for producing heat sinterable metal fine particles of the present invention, the average particle diameter of the heat sinterable metal fine particles whose surface is coated with an organic substance having 5 to 24 carbon atoms having a polar group is determined by the heat sinterability. In this respect, it is 0.005 μm to 0.2 μm. This average particle size is the average particle size of the primary particles. When the average particle size exceeds 0.2 μm, the aggregation of the heat-sinterable metal fine particles decreases, and the significance of improving the sinterability by improving the dispersibility of the heat-sinterable metal fine particles according to the present invention decreases. . Therefore, the average particle diameter is preferably 0.2 μm or less, and more preferably 0.1 μm or less. In addition, when it is less than 0.005 μm, the surface activity of the heat-sinterable metal fine particles is too strong, and the storage stability of the paste-like metal fine particle composition may be lowered, so that it is 0.005 μm or more and 0.01 μm. More preferably. These heat-sinterable metal fine particles may be used alone, or a plurality of heat-sinterable metal fine particles having different average particle diameters and shapes may be used in combination.

The average particle diameter may be a 50% particle diameter by a laser diffraction method (see Japanese Patent Application Laid-Open No. 2003-55701) or a median diameter D50 such as a volume cumulative particle size D50 (see Japanese Patent Application Laid-Open No. 2007-84860). If this is not possible, the number average particle diameter calculated by image analysis of an image taken with an electron microscope may be used.

Laser diffraction / scattering particle size distribution measurement method irradiates a heat-sinterable metal fine particle with a laser beam and measures the intensity of the diffracted light and scattered light emitted in various directions according to the size of the metal fine particle. This is a general-purpose measurement method in which the primary particle size is determined. Many measuring devices are commercially available (for example, a laser diffraction particle size distribution measuring device SALD manufactured by Shimadzu Corporation, a laser diffraction scattering particle size distribution measuring device Microtrac manufactured by Nikkiso Co., Ltd.), and using these, the average particle size can be easily obtained. The diameter (median diameter D50) can be measured. When the heat-sinterable metal fine particles are strongly aggregated, it is preferably measured after being dispersed in a primary particle state by a homogenizer.

The method for producing the heat-sinterable fine metal particles is not particularly limited, and examples thereof include a reduction method, a pulverization method, an electrolysis method, an atomization method, a heat treatment method, and a combination thereof. In particular, the reduction method is preferable.

Polar group definitive organic matter carbon atoms 5-24 having precoated with that polar groups of the surface of the heat sintering metal fine particles is preferably made of carbon and hydrogen atoms and an oxygen atom, a carboxyl group More preferred. The organic substance is preferably a fatty acid which is an aliphatic carboxylic acid.

As such fatty acids, pentanoic acid (valeric acid), hexanoic acid (caproic acid), heptanoic acid (enanthic acid), octanoic acid (caprylic acid), nonanoic acid (pelargonic acid), decanoic acid (capric acid), dodecanoic acid (Lauric acid), tetradecanoic acid (myristic acid), pentadecanoic acid, hexadecanoic acid (palmitic acid), heptadecanoic acid (margaric acid), octadecanoic acid (stearic acid), 12-hydroxyoctadecanoic acid (12-hydroxyoleic acid), eicosane Monovalent linear saturated fatty acids such as acids (arachidic acid), docosanoic acid (behenic acid), tetracosanoic acid (lignoceric acid), hexacosanoic acid (serotic acid), octacosanoic acid (montanic acid); 2-pentylnonanoic acid, 2- Monovalent such as hexyl decanoic acid, 2-heptyldodecanoic acid, isooleic acid, etc. Branched saturated fatty acids; monovalent unsaturated fatty acids such as sorbic acid, maleic acid, palmitoleic acid, oleic acid, isooleic acid, elaidic acid, linoleic acid, linolenic acid, ricinoleic acid, gadrenic acid, erucic acid, ceracolic acid Is done.

Examples of such fatty acids include oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, oxydiacetic acid (diglycolic acid), glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid, diacid Examples include polyvalent aliphatic carboxylic acids such as glycolic acid. Examples of the organic substance having 5 to 24 carbon atoms having a polar group further include polyvalent aromatic carboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid.

The organic substance having a polar group that covers the surface of the heat-sinterable metal fine particles in advance has 5 to 24 carbon atoms, but the average particle size of the heat-sinterable metal fine particles is less than 0.1 μm and 5 to 5 carbon atoms. 12 is preferable.

The polymer dispersant having an acidic functional group and a basic functional group for preliminarily covering the surface of the heat-sinterable fine metal particles and replacing an organic substance having 5 to 24 carbon atoms having a polar group has a polar group. Instead of the organic substance having 5 to 24 carbon atoms, the surface of the heat-sinterable metal fine particles is adsorbed or coordinated to coat the surface, thereby improving the dispersibility of the heat-sinterable metal fine particles and the heating. The improved dispersibility of the sinterable metal fine particles has the effect of improving the heat sinterability of the heat sinterable metal fine particles.

A polymer dispersant having an acidic functional group and a basic functional group is also referred to as an amphoteric polymer dispersant. Has an acidic functional group and basic functional group, may have a water acid groups further.

As the acidic functional group, carboxyl group, acid anhydride group, Li phospho groups, acidic phosphoric acid ester group, phosphonic acid group are exemplified, preferably a carboxyl group, a phosphoric acid or acidic phosphoric acid ester group . The acidic phosphate group is one in which a part of the phosphorus-bonded hydroxyl group is alkoxylated. Examples of the alkoxy group include lower alkoxy groups such as a methoxy group, an ethoxy group, and a propoxy group. The number of carbon atoms of the lower alkoxy group is preferably 1-8.
Examples of the basic functional group include an amino group, an imino group (= NH), an ammonium base, and a heterocyclic group having a basic nitrogen atom, but an amino group, an ammonium base (for example, a tertiary ammonium base, A quaternary ammonium base). The amino group may be any of a primary amino group (—NH ₂ ), a secondary amino group (—NHR), and a tertiary amino group (—NRR ′). R and R ′ are an alkyl group, a phenyl group, an aralkyl group and the like, and preferably have 1 to 8 carbon atoms.
The tertiary amino group has excellent adsorptivity to the surface of the heat-sinterable metal fine particles.

In the polymer having an acidic functional group and a basic functional group, a part of the acidic functional group in the molecule may be neutralized or chlorinated with a basic compound. Examples of basic compounds used for neutralization or chlorination include nitrogen-containing organic compounds such as hydroxides of alkali metals and alkaline earth metals, ammonia, alkylamines, amide amines, alkanolamines, and morpholine. Examples of the alkali metal or alkaline earth metal hydroxide include sodium hydroxide, potassium hydroxide, magnesium hydroxide and the like. Specific examples of alkylamines include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine. And ethylenediamine. The alkyl group and alkylene group preferably have 1 to 8 carbon atoms.

Further, a part of the basic functional group in the molecule may be neutralized or salified with an acidic compound. Examples of the acidic compound used for neutralization or chlorination include phosphoric acid, partially alkyl esterified phosphoric acid (acidic phosphoric acid ester), and carboxylic acid (for example, lower aliphatic monocarboxylic acid and lower aliphatic dicarboxylic acid). These carboxylic acids preferably have 1 to 8 carbon atoms. A part of the acidic functional group may form a salt with the basic functional group.

The acidic functional group is easily adsorbed or coordinated on the surface of the heat-sinterable metal fine particles, and is effective in improving the dispersibility of the heat-sinterable metal fine particles. The basic functional group is heat-sinterable. It is effective for improving the sinterability of metal fine particles. By coating the surface of the heat-sinterable metal fine particles with a polymer dispersant having both of these acidic functional groups and basic functional groups, the dispersibility and heat-sinterability of heat-sinterable metal fine particles are significantly improved. It becomes.

The acid value of the polymer dispersant having an acidic functional group and a basic functional group is preferably 5 to 300 mgKOH / g, and more preferably 10 to 200 mgKOH / g. Further, the amine value of the polymer dispersant is preferably 5 to 300 mgKOH / g, more preferably 10 to 200 mgKOH / g.
The acid value represents the acid value per 1 g of the solid content of the polymer dispersant, and can be determined by potentiometric titration according to JIS K 0070. The amine value represents the amine value per gram of the polymer dispersant solid content, and is a value converted to an equivalent of potassium hydroxide after being obtained by potentiometric titration using a 0.1N hydrochloric acid aqueous solution.

In the polymer dispersant, the bonding position of the acidic functional group and the basic functional group to the polymer main body is not particularly limited, and may be a main chain, a side chain, a main chain and a side chain. May be located. The acidic functional group and the basic functional group may be directly bonded to the polymer main body or may be bonded via a linking group. As a linking group, a lower alkylene group such as an ethylene group to an octylene group, a phenylene group, a low intermediate alkylene group having an ether bond in the chain, a low intermediate alkylene group having a carboxylic acid ester bond in the chain, a carboxylic acid amide in the chain Examples are low and intermediate alkylene groups having a bond. The lower alkylene group preferably has 1 to 8 carbon atoms, and the lower intermediate alkylene group having an ether bond in the chain preferably has 2 to 12 carbon atoms in total.

The polymer dispersant means a dispersant composed of a polymer. The object to be dispersed is fine powder or fine particles (for example, pigments, fillers). Since it is a polymer, the weight average molecular weight is usually 1,000 or more. The weight average molecular weight is preferably in the range of 2,000 to 150,000, and more preferably in the range of 3,000 to 100,000. The weight average molecular weight (Mw) is a polystyrene equivalent weight average molecular weight measured by gel permeation chromatography (carrier: tetrahydrofuran). When the weight average molecular weight of the polymer dispersant is within the above range, the substitution property of the organic substance having a polar group is improved, and the storage stability and heat sintering of the heat-sinterable metal fine particles coated with the polymer dispersant are improved. Property is improved.

As the polymer dispersant having an acidic functional group and a basic functional group, a synthetic product or a commercially available product may be used.

As a polymer dispersant having a commercially available acidic functional group and basic functional group, SOLSPERSE24000 (acid value: 24 mgKOH / g, amine value: 47 mgKOH / g), SOLSPERSE32000 (acid value: 15 mgKOH / g, amine value: 180 mgKOH / g) ) (Manufactured by Lubrizol, Ltd.) (SOLSPERSE is a registered trademark of Lyubrizol Limited);

DISPERBYK-106 (acid value: 132 mgKOH / g, amine value: 74 mgKOH / g), DISPERBYK-130 (acid value: 2 mgKOH / g, amine value: 190 mgKOH / g), DISPERBYK-140 (acid value: 73 mgKOH / g, amine) Value: 76 mg KOH / g), DISPERBYK-142 (acid value: 46 mg KOH / g, amine value: 43 mg KOH / g), DISPERBYK-145 (acid value: 76 mg KOH / g, amine value: 71 mg KOH / g), DISPERBYK-180 (acid) Value: 94 mgKOH / g, amine value: 94 mgKOH / g), DISPERBYK-187 (acid value: 35 mgKOH / g, amine value: 35 mgKOH / g), DISPERBYK-191 (acid value: 30 mgKOH / g, amine value: 20 mgKOH / g) ), DISPERBYK-2001 (acid value: 19 mgKOH / g, amine value: 29 mgKOH / g), DISPERBYK-2010 (acid value: 20 mgKOH / g, amine value: 20 mgKOH / g), D ISPERBYK-2020 (acid value: 37 mgKOH / g, amine value: 36 mgKOH / g), DISPERBYK-2020N (acid value: 36 mgKOH / g, amine value: 36 mgKOH / g), DISPERBYK-2025 (acid value: 38 mgKOH / g, amine) Price: 37 mgKOH / g) and other Dispersic series products [BIC Chemie Japan Co., Ltd. sales] (DISPERBYK is a registered trademark of Bik-Hemi Geselsyaft Mituto Beschlenktel Huffung);

BYK-9076 (acid value: 38 mgKOH / g, amine value: 44 mgKOH / g), ANTI-TERRA-U (acid value: 24 mgKOH / g, amine value: 19 mgKOH / g), ANTI-TERRA-U100 (acid value: 50 mgKOH) / G, amine value: 35 mgKOH / g), ANTI-TERRA-204 (acid value: 41 mgKOH / g, amine value: 37 mgKOH / g), ANTI-TERRA-205 (acid value: 40 mgKOH / g, amine value: 37 mgKOH / g), ANTI-TERRA-250 (acid value: 46 mgKOH / g, amine value: 41 mgKOH / g), etc., BIC series products, Antiterra series products [BIC Chemie Japan Co., Ltd. products] (BYK and ANTI-TERRA are Biik-Hemmy Geselsyaft Mitts Beschlenktel is a registered trademark of Haftung);

  Disparon DA-234 (acid value: 16 mg KOH / g, amine value: 20 mg KOH / g), Disparon DA-325 (acid value: 14 mg KOH / g, amine value: 20 mg KOH / g) and other Disparon series products [Enomoto Kasei Co., Ltd. Manufactured] Disparon is a registered trademark of Enomoto Kasei Co., Ltd .; Azisper PB-821 (acid value: 17 mg KOH / g, amine value: 10 mg KOH / g), Azisper PB-822 (acid value: 14 mg KOH / g, amine value) : Ajisper PB-881 (acid value: 17 mgKOH / g, amine value: 17 mgKOH / g) and the like. Ajisper series products [manufactured by Ajinomoto Fine Techno Co., Ltd.] are exemplified. Registered trademark).

These polymer dispersants may be used alone or in combination of two or more.

As the polymer of the polymer dispersant having an acidic functional group and a basic functional group, a synthetic polymer is preferable, and a vinyl polymerization polymer and a condensation polymerization polymer are representative.

The acidic functional group and the basic functional group in the vinyl polymerization polymer having an acidic functional group and a basic functional group are derived from monomers at the time of vinyl polymerization, respectively.
Examples of vinyl monomers having an acidic functional group include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid, crotonic acid, fumaric acid, maleic acid monoalkyl ester, and fumaric acid monoalkyl ester. Examples thereof include carboxyl group-containing vinyl monomers.

Examples of the monomer having a basic function include N, N-dimethylaminoethyl (meth) acrylate, N-methylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, and N, N-dimethylamino. Examples include aminoalkyl group-containing acrylates and aminoalkyl group-containing methacrylates such as propyl (meth) acrylate, Nt-butylaminoethyl (meth) acrylate, N, N-dimethylaminobutyl (meth) acrylate, and N, N- Examples include aminoalkyl group-containing acrylamides and aminoalkyl group-containing methacrylamides such as dimethylaminoethyl (meth) acrylamide and N, N-dimethylaminopropyl (meth) acrylamide. The term “(meth) acryl” means “acryl or methacryl”.
Furthermore, amino group-containing styrene such as vinylpyridine, 4-aminostyrene, 4- (N, N-dimethylamino) styrene and the like can be mentioned.

In addition to the acidic functional group-containing vinyl monomer and the basic functional group-containing vinyl monomer, other vinyl monomers may be used as the copolymerization monomer. Other vinyl monomers are typically vinyl monomers that do not contain a functional group, and include (meth) acrylic acid alkyl esters, α, β-unsaturated carboxylic acid polyalkylene glycol esters, vinyl acetate, vinyl butyrate and other fatty acids. Vinyl esters, aromatic vinyl compounds such as styrene and α-methylstyrene, vinyl ethers, α-C _2-20 olefins (ethylene, propylene, 1-butene, isobutylene, 1-hexene, 1-octene, 1-dodecene, etc.) And olefin monomers. And hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate.

As for the carbon atom number of the alkylester part of the said (meth) acrylic acid alkylester, 1-20 are preferable, (meth) acrylic acid methyl, (meth) acrylic acid ethyl, (meth) acrylic acid butyl, ( Examples include 2-ethylhexyl (meth) acrylate, cyclohexyl methacrylate, lauryl (meth) acrylate, tridecyl methacrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, and allyl (meth) acrylate.

Examples of the α, β-unsaturated carboxylic acid polyalkylene glycol ester include polypropylene glycol methacrylate, polyethylene glycol methacrylate, polyethylene glycol methacrylate glycol, polyethylene glycol monomethacrylate polytetramethylene glycol, and methoxypolyethylene glycol methacrylate. .

The method for polymerizing these vinyl monomers is the same as the conventional polymerization method for obtaining a vinyl polymer, but it is necessary to adjust the monomer ratio so that the intended acid value and amine value can be obtained. . A polymerization reaction catalyst is used in the polymerization, and water, a water-soluble organic solvent, a polymerization initiator, a chain transfer agent, or the like is used as necessary.

Block polymerization may be performed after polymerizing the acidic functional group-containing vinyl monomer and the basic functional group-containing vinyl monomer, respectively, or only one of them may be polymerized and then the other graft-polymerized. Good.

The carboxyl group-containing vinyl monomer and the vinyl monomer having no functional group are copolymerized to synthesize an acidic functional group-containing vinyl polymer, and aliphatic diamines such as ethylenediamine and propylenediamine are part of the carboxyl groups in the molecule. Can be reacted to form a salt or amide to give a carboxyl group and an amino group.

Aminoalkyl group-containing vinyl polymers are synthesized by copolymerizing aminoalkyl group-containing acrylates and aminoalkyl group-containing methacrylates with vinyl monomers that do not have functional groups, and phthalic acid anhydride is added to some of the aminoalkyl groups in the molecule. Carboxyl groups and amino groups can be provided by reacting dicarboxylic acids such as phthalic acid, succinic acid, succinic anhydride, and adipic acid to form salts or amides.
A phosphoric acid group and an amino group can be provided by reacting a part of the aminoalkyl group in the molecule with phosphoric acid to form a salt or amide.

Polymers having acidic functional groups and basic functional groups include homopolymers and copolymers.
Copolymers include random copolymers, alternating copolymers, block copolymers, comb copolymers (or comb graft copolymers).

The block copolymer having an acidic functional group and a basic functional group is composed of an A block and a B block, and the A block is an amino group-containing vinyl monomer such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, t A segment consisting essentially of butylaminoethyl (meth) acrylate, vinylpyridine, 4-aminostyrene, 4- (N, N-dimethylamino) styrene, wherein the B block comprises an acidic functional group-containing vinyl monomer and at least 1 A segment containing a vinyl monomer that does not contain one functional group.

In certain embodiments, the A block is a homoblock of amino group-containing vinyl monomers. Suitable acidic functional group-containing vinyl monomers include methacrylic acid and acrylic acid, and suitable vinyl monomers not containing functional groups include, for example, benzyl methacrylate, butyl (meth) acrylate, methyl methacrylate, butyl methacrylate, ethyl hexyl methacrylate, Examples include 2-phenylethyl methacrylate, ethyl acrylate, hydroxyethyl acrylate, butyl acrylate, and 2-phenylethyl acrylate.

The acid value of the block copolymer having an acidic functional group and a basic functional group may be larger, the same or smaller than the amine value. Further, the B block does not contain an amino group-containing vinyl monomer.

Typically, the A block segment is from about 2 to about 16 units of amino group-containing vinyl monomer, more typically from about 2 to about 10 units of amino group-containing vinyl monomer. The B block does not contain at least 4 units of acidic functional group-containing vinyl monomer, more additionally, at least about 6 to about 11 units of acidic functional group-containing vinyl monomer, and at least about 16 units of at least one functional group. A vinyl monomer, more typically a segment comprising at least about 20 units of vinyl monomer having no at least one functional group.

Typically, the block copolymer has a number average molecular weight (Mn) of about 2000 to about 16,000 daltons, more typically about 3,000 to about 12,000 daltons, and an acid number of about 50 to about 220 ( MgKOH for neutralizing 1 gram of polymer solids), more typically from about 30 to about 200. Typically, the amine number is from about 10 to about 180 mg KOH / g solids, more typically from about 25 to about 100 mg KOH / g solids.

Typically, the block copolymer having an acidic functional group and a basic functional group is an AB, ABA or BAB block copolymer, but an AB block copolymer having a homoblock of an amino group-containing vinyl monomer is typically typical.

Polycondensation polymers such as polyurethane, polyester, polyoxyalkylene, polyoxyalkylene / polyester copolymer, polyamide, phenol resin, urea resin, melamine resin, polycarbonate, epoxy resin, alkyd resin, polyalkyleneimine (polyethyleneimine, etc.), Nitrogen-containing polymers such as polyvinyl pyrrolidone, polyallylamine, polyether polyamine (polyoxyethylene polyamine, etc.) are mentioned.
Polyurethanes, polyesters, polyoxyalkylenes (eg, polyoxyethylene propylene, polyoxypropylene), polyoxyalkylene / polyester copolymers, polyamides, chain-containing structures having a chain structure in that they easily have acidic functional groups and basic functional groups. Nitrogen polymers are preferred.

The acidic functional group and the basic functional group can be introduced into the polymer by incorporating a monomer or oligomer having an acidic functional group and a monomer or oligomer having a basic functional group into a condensation polymerization reaction. In addition, a monomer or oligomer having an acidic functional group or a monomer or oligomer having a basic functional group is incorporated into a condensation polymerization reaction, and a part of the acidic functional group or basic functional group in the molecule has a basic functional group Alternatively, an acidic functional group and a basic functional group can be introduced into the polymer by modification with a compound having an acidic functional group. In addition, by reacting a reactive group such as a hydroxyl group in the polymer with a compound having a basic functional group and a compound having an acidic functional group, the acidic functional group and the basic functional group are introduced into the polymer. can do.

A typical polyurethane has a main chain of polyurethane and has a polyether (particularly, polyoxyethylene, polyoxypropylene or polyoxyethylenepropylene) or polyester in the side chain. Those having an acidic functional group (for example, a carboxyl group, a phosphoric acid group, an acidic phosphoric ester group) and a basic functional group (for example, an amino group such as a tertiary amino group) at the end of the side chain are preferable.

The polyester is typically a polycondensate of aliphatic dicarboxylic acid or aromatic dicarboxylic acid and alkylene glycol. For example, dicarboxylic acid (phthalic acid, phthalic anhydride, succinic acid, succinic anhydride, adipic acid, etc.) and alkylene glycol (ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanedi And a polycondensate of a small amount of a tricarboxylic acid (such as citric acid) and a polycondensate of a dicarboxylic acid, an alkylene glycol and a small amount of an alkylene triol. For example, a carboxyl group and an amino group can be provided by reacting an aliphatic diamine such as ethylenediamine or propylenediamine with a part of the carboxyl group in the molecule to form a salt or amide.

The heat-sinterable metal fine particles having an average particle diameter of 0.005 μm to 0.2 μm in the present invention are so-called nano metal fine particles, and have a very high surface activity, and thus easily aggregate. In order to prevent this, the surface of the nano metal fine particles is coated with an organic substance having 5 to 24 carbon atoms having a polar group in the production process, but the aggregation tends to proceed with time. In the present invention, it is possible to effectively prevent aggregation while maintaining high surface activity by replacing the organic substance of such nanometal fine particles with a polymer dispersant having an acidic functional group and a basic functional group. .

The heat-sinterable metal fine particle in the present invention has an acidic functional group and a basic functional group, the organic material of the heat-sinterable metal fine particle coated with an organic material having 5 to 24 carbon atoms having a polar group on the surface. It is manufactured by replacing with a polymer dispersant until the exothermic peak due to the decomposition of the organic matter of the heat-sinterable metal fine particles is not detected in the differential thermal analysis.

The substitution method is not particularly limited. For example, a method of immersing the heat-sinterable metal fine particles coated with an organic substance having 5 to 24 carbon atoms having a polar group on the surface of the polymer dispersant. Is preferred. At this time, the liquid may be stirred or shaken by a stirrer, a shaker, an ultrasonic vibrator, or the like.

At this time, when the polymer dispersant is solid at room temperature, it is preferably used after being dissolved in an organic solvent such as a lower alcohol, ketone, ester or hydrocarbon. The mixing ratio of the polymer dispersant and the organic solvent is not particularly limited as long as the polymer dispersant can be dissolved.

Although the temperature at the time of the said immersion is not specifically limited, In order to suppress aggregation of heat-sinterable metal fine particles, it is preferable that it is below normal temperature. The dipping time is not particularly limited as long as it is sufficient to remove the organic substance having 5 to 24 carbon atoms having a polar group that coats the surface of the heat-sinterable metal fine particles. Next, the heat-sinterable metal fine particles are separated by filtering the immersion liquid or the mixture.

The surface of the heat-sinterable metal fine particles separated in this way is coated with the polymer dispersant. If an excessive amount of the polymer dispersant is adhered, In order to improve the sinterability at a low temperature, it is preferable to remove such excess. In addition, in the case where an organic substance having 5 to 24 carbon atoms having a polar group that has previously coated the surface of the heat-sinterable metal fine particles is attached, the remaining organic substance is sinterability of the heat-sinterable metal fine particles. In the case of lowering, it is preferable to remove these as well.

For that purpose, it is preferable to wash the separated heat-sinterable metal fine particles with a volatile organic solvent, and examples of the volatile organic solvent include acetone, methanol, ethanol, isopropyl alcohol, methyl ethyl ketone, dimethyl sulfoxide, and tetrahydrofuran. Is done. This is because these organic solvents have a low boiling point and high volatility, and therefore can be easily removed by air drying or drying under reduced pressure at room temperature. Further, when the heat-sinterable metal fine particles are produced by a reduction method, there is an advantage that the organic reducing agent attached to the heat-sinterable metal fine particles is also removed.

The amount of the above-described polymer dispersing agent covering the surface of the heat-sinterable metal fine particles thus obtained is determined by the sinterability of the heat-sinterable metal fine particles, the strength of the solid metal obtained by sintering, and the electric conduction. From the standpoints of heat conductivity and thermal conductivity, it is preferably 0.01 to 10.0% by mass, more preferably 0.1 to 5% by mass.

The amount of the polymer dispersant covering the heat-sinterable metal fine particles can be measured by a usual method. Heat-sinterable metal fine particles coated with the above polymer dispersant are in an air stream (in the case where the heat-sinterable metal fine particles are easily oxidized, it is preferably in an inert gas stream such as nitrogen or in a reducing gas stream such as hydrogen. ), And the polymer dispersant adhering to the heat-sinterable fine metal particles is removed by decomposition, volatilization, or combustion, and the weight loss is measured. In this case, if the organic reducing agent remains on the surface of the heat sinterable metal fine particles or in the heat sinterable metal fine particles, the total amount thereof is quantified, but the residual amount of the organic reducing agent is very small. So it can be ignored.

In the heat-sinterable metal fine particles coated on the surface with an organic substance having 5 to 24 carbon atoms having a polar group, the surface of the heat-sinterable metal fine particles may be oxidized. However, when the heat-sinterable metal fine particles are heat-sinterable silver fine particles, if the ratio of silver oxide is high, a large amount of oxygen is generated during heating, causing voids in the solid silver produced by sintering. Therefore, the ratio of the surface being silver oxide is preferably 50% or less, more preferably 20% or less, and further preferably 2% or less. Especially in use cases such as die-bonding agents that become semi-sealed with a relatively large bonding area due to large chip connection such as memory and CPU, the presence of silver oxide causes a decrease in adhesive strength due to void generation. 10% or less is preferable.

When producing heat-sinterable metal fine particles having an average particle diameter of 0.005 μm to 0.2 μm, organic substances having 5 to 24 carbon atoms having a polar group, such as hexanoic acid, octanoic acid, stearic acid, Direct coating with a polymer dispersant having an acidic functional group and a basic functional group without coating with oleic acid or the like makes it difficult to control the particle size of the heat-sinterable metal fine particles, and heat sintering with a stable particle size. It is impossible to efficiently produce the fine metal particles.

Heat-sinterable metal fine particles coated with a polymer dispersant having an acidic functional group and a basic functional group have high heat-sinterability, so heat is not applied as much as possible until a paste-like metal fine composition is formed. Better.

The paste-like fine metal particle composition (I) of the present invention has (A) an average particle diameter of 0.005 μm to 0.2 μm, and its surface is coated with an organic substance having 5 to 24 carbon atoms having a polar group. In the differential thermal analysis, the exothermic peak due to the decomposition of the organic matter of the heat-sinterable metal fine particles is detected by using a polymer dispersant having an acidic functional group and a basic functional group. Heat-sinterable metal fine particles that are substituted until they are eliminated, (B) a volatile dispersion medium having a boiling point of 70 ° C. to 300 ° C., and (C) a monovalent or divalent carboxylic acid having 2 to 10 carbon atoms, The volatile dispersion medium (B) is volatilized by heating, and the heat-sinterable metal fine particles (A) are sintered together.

The paste-like fine metal particle composition (II) of the present invention has (A) an average particle diameter of 0.005 μm to 0.2 μm, and the surface thereof is an organic substance having 5 to 24 carbon atoms having a polar group. In the differential thermal analysis, the exothermic peak due to the decomposition of the organic matter of the heat-sinterable metal fine particles by using a polymer dispersant having an acidic functional group and a basic functional group, Heat-sinterable metal fine particles substituted until no more is detected, (B) a volatile dispersion medium having a boiling point of 70 ° C to 300 ° C, and (C) a monovalent or divalent carbon having 2 to 10 carbon atoms It consists of an acid and (D) heat-sinterable metal particles having an average particle size of more than 0.2 μm and not more than 10 μm. The volatile dispersion medium (B) is volatilized by heating, and the heat-sinterable metal fine particles (A ) And heat-sinterable metal particles (D) are sintered. That.

In the paste-like metal fine particle composition of the present invention, the powdered heat-sinterable metal fine particles (A), or the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D) are volatile dispersion media ( It is made into a paste by the action of B). By making a paste, it can be discharged in a thin line form from a cylinder or nozzle, and it can be easily applied with a metal mask, and can be easily applied to the shape of an electrode. The paste form includes a cream form and a slurry form.

The volatile dispersion medium is used instead of the non-volatile dispersion medium because the heat-sinterable metal fine particles (A) or the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D) are heated. When the dispersion medium volatilizes in advance during sintering, the heat-sinterable metal fine particles (A), or the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D) are easily sintered, This is because the strength, electrical conductivity, and thermal conductivity of the solid metal or solid metal alloy are likely to increase. The volatile dispersion medium (B) does not alter the surface of the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D), and has a boiling point of 70 ° C. or higher and 300 ° C. or lower. preferable. When the boiling point is less than 70 ° C, the volatile dispersion medium (B) is easily volatilized during the operation of preparing the paste-like metal fine particle composition, and when the boiling point is higher than 300 ° C, the heat-sinterable silver metal fine particles ( This is because the volatile dispersion medium (B) may remain even after A) is sintered.

The heat-sinterable metal particles (D) are heat-sinterable metal particles having an average particle size of more than 0.2 μm and 10 μm or less that can be produced at a lower cost than nano metal particles. Examples of such heat-sinterable metal particles include particles such as reduced silver, atomized silver, silver colloid, silver alloy, surface silver-coated powder, gold, palladium, copper, tin, and solder alloy. Silver particles are preferable from the viewpoint of property, and silver particles produced by a reduction method are more preferable. Next, copper particles are preferred.

Examples of the shape of the heat-sinterable metal particles (D) are spherical, acicular, angular, dendritic, fibrous, flaky (single), granular, irregular, and teardrop (JIS Z2500: 2000), and further elliptical, spongy, grape, spindle, approximately cubic, hexagonal plate, columnar, rod, porous, lump, square, round, etc. From the viewpoint of easy procurement, it is preferably spherical, granular and flaky.

The spherical shape referred to here is a shape that is almost a sphere (see JIS Z2500: 2000). The spherical shape is not necessarily required, and the ratio of the major axis (DL) to the minor axis (DS) of the particle (DL) / (DS) (sometimes referred to as spherical coefficient or sphericity) is 1.0 to 1. Those in the range of .2 are preferred.
Granular is not an irregular shape but a shape with almost equal dimensions (see JIS Z2500: 2000).

The flake shape (strip shape) is a plate-like shape (see JIS Z2500: 2000) and is also called a scale shape because it is a thin plate shape like a scale.

The aspect ratio of the flaky metal particles referred to here is a value of [average length of particles in the plane direction (μm)] / [average thickness of particles (μm)], and is in the range of 2 to 200. A thing is preferable and it is more preferable that it is the range of 5-50. In calculating the aspect ratio, the value of the average length in the plane direction is, for example, observed with a scanning electron microscope at a magnification of about 1000 to 10,000 times, and the length in the plane direction of 20 or more metal particles in the observed image. Can be obtained as an average value. The average thickness value is, for example, a sample in which flaky metal particles are hardened with a curable resin such as an epoxy resin, and the cross section of the sample is observed with a scanning electron microscope at a magnification of about 5000 to 20000 times. Then, the thickness of 20 or more metal particles in the observed image can be measured and obtained as the average value. No matter the shape, the particle size distribution is not limited.

The average particle diameter of the heat-sinterable metal particles (D) is the average particle diameter of primary particles obtained by a laser diffraction / scattering particle size distribution measurement method. When the average particle size of the heat-sinterable metal particles exceeds 10 μm, the heat-sinterability is lowered, and therefore it is preferably 7 μm or less. However, if the average particle size is 0.2 μm or less, aggregation tends to occur and the dispersibility decreases, so the average particle size exceeds 0.2 μm, but is preferably 0.4 μm or more.

The ratio of the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D) coated with the polymer dispersant having an acidic functional group and a basic functional group is not limited, but is 50 to 10 in mass ratio. : It is preferable that it is 50-90.

The volatile dispersion medium (B) is a heat-sinterable metal fine particle (A) coated with a polymer dispersant having an acidic functional group and a basic functional group, or a heat-sinterability coated with a polymer dispersant. The metal fine particles (A) and the heat-sinterable metal particles (D) may be made into a paste, for example, a volatile hydrocarbon compound composed of carbon atoms and hydrogen atoms, a volatile organic composed of carbon atoms, hydrogen atoms and oxygen atoms. A volatile organic compound comprising a compound, a carbon atom, a hydrogen atom and a nitrogen atom, a volatile organic compound comprising a carbon atom, a hydrogen atom, an oxygen atom and a nitrogen atom, and a hydrophilic volatile organic compound among the volatile organic compounds It is selected from a mixture with water and the like, and preferably has a boiling point of 70 ° C to 300 ° C. These are usually liquid at room temperature.

Specifically, as volatile organic compounds composed of carbon atoms, hydrogen atoms and oxygen atoms, fats such as ethyl alcohol, propyl alcohol, butyl alcohol, pentyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol and decyl alcohol Monohydric alcohol; ethylene glycol monomethyl ether (methyl cellosolve, methyl carbitol), ethylene glycol monoethyl ether (emethyl cellosolve, ethyl carbitol), ethylene glycol monopropyl ether (propyl cellosolve, propyl carbitol), ethylene glycol mono Ethers such as butyl ether (butyl cellosolve, butyl carbitol), propylene glycol monomethyl ether, methylmethoxybutanol Aliphatic monohydric alcohol having a bond; phenylalkyl alcohol such as benzyl alcohol and 2-phenylethyl alcohol; ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, butanediol, Examples include aliphatic polyhydric alcohols such as pentanediol, hexanediol, octanediol and glycerin; terpene alcohols such as prenol, terpineol, 3-methyl-3-buten-2-ol, farnesol, citronellol, nerolidol and sclareol The

Furthermore, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol (4-hydroxy-4-methyl-2-pentanone), 2-octanone, isophorone (3,5,5-trimethyl-2-cyclohexene-1- ON), volatile aliphatic ketones such as dibutylketone (2,6-dimethyl-4-heptanone); ethyl acetate (ethyl acetate), butyl acetate, acetoxyethane, methyl butyrate, methyl hexanoate, methyl octoate, decane Aliphatic carboxylic acid esters such as methyl acid, methyl cellosolve acetate, propylene glycol monomethyl ether acetate, 1,2-diacetoxyethane; tetrahydrofuran, dipropyl ether, ethylene glycol dimethyl ether, ethylene glycol Ethyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, ethoxyethyl ether, 1,2-bis (2-diethoxy) ethane, 1,2-bis (2-methoxyethoxy) ethane, bis [2- (2-methoxyethoxy) Aliphatic ethers such as) ethyl] ether. Other examples include ester ethers such as 2- (2-butoxyethoxy) ethane acetate and ether alcohols such as 2- (2-methoxyethoxy) ethanol.

As a volatile hydrocarbon compound comprising a carbon atom and a hydrogen atom, a volatile aliphatic hydrocarbon such as n-paraffin or isoparaffin having preferably 6 to 16 carbon atoms; a carbon atom number such as toluene or xylene is preferably 6 To 16 volatile aromatic hydrocarbons; terpene hydrocarbons such as limonene, kazumalene and α-pinene.

Examples of volatile organic compounds composed of carbon atoms, hydrogen atoms and nitrogen atoms include volatile alkyl nitriles such as acetonitrile and propionitrile.
Examples of volatile organic compounds composed of carbon atoms, hydrogen atoms, oxygen atoms and nitrogen atoms include volatile aliphatic carboxylic acid amides such as acetamide, dimethylacetamide and N, N-dimethylformamide. In addition, alkylamide solvents having an ether bond, nitrile solvents such as acetonitrile, sulfur-containing solvents such as dimethyl sulfoxide, urea solvents such as tetramethylurea, low molecular weight volatile silicone oils and volatile organic modified silicones Oil is exemplified.
Two or more volatile dispersion media (B) may be used in combination.

The compounding amount of the volatile dispersion medium (B) is the heat-sinterable metal fine particles (A) coated with the polymer dispersant having acidic functional groups and basic functional groups, or the heat-sinterable metal fine particles (A). And sufficient amount to paste the heat-sinterable metal particles (D) into a paste, and as a guide, heat-sinterable metal fine particles (A) 100 parts by mass, or heat-sinterable metal fine particles (A) and heat It is 5-30 mass parts per 100 mass parts of total amounts of a sinterable metal particle (D), Preferably it is 8-20 mass parts.

The paste-like fine metal particle composition of the present invention contains a monovalent or divalent carboxylic acid (C) having 2 to 10 carbon atoms. Thereby, the sinterability of the metal fine particles (A) coated with the polymer dispersant can be improved. Such carboxylic acids (C) are acetic acid, propionic acid, butyric acid, pentanoic acid (valeric acid), hexanoic acid (caproic acid), heptanoic acid (enanthic acid), octanoic acid (caprylic acid), nonanoic acid (pelargonic acid) ), Decanoic acid (capric acid), crotonic acid, sorbic acid, maleic acid and the like monovalent fatty acids; oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, pimelic acid, speric acid, Polycarboxylic acids such as azelaic acid, sebacic acid, diglycolic acid, cyclohexene dicarboxylic acid, cyclopentanetetracarboxylic acid; hydroxycarboxylic acids such as lactic acid, malic acid, citric acid; benzoic acid, phthalic acid, isophthalic acid, terephthalic An aromatic carboxylic acid such as an acid is exemplified, but an aliphatic carboxylic acid is preferable.

The addition amount of the monovalent or divalent carboxylic acid (C) having 2 to 10 carbon atoms is preferably such that 0.01 to 5% by mass in the paste-like metal fine particle composition of the present invention. . When the addition amount of the fatty acid is less than 0.01% by mass, the sinterability of the paste-like fine metal particle composition of the present invention is difficult to improve, and when the addition amount of the fatty acid exceeds 5% by mass, When the paste-like metal fine particle composition of the present invention is heated, the fatty acid volatilizes suddenly, and the sintered product of the heat-sinterable metal fine particles (A) or the heat-sinterable metal fine particles (A) and the heat-fired This is because cracks are easily generated in the sintered product of the binder metal particles (D).

In addition to this, it contains non-sinterable metal particles, non-metallic powders, metal compounds, metal complexes, thixotropic agents, stabilizers, colorants, etc. You may do it.

The paste-like fine metal particle composition (I) of the present invention is heated so that the volatile dispersion medium (B) is volatilized, and the heat-sinterable fine metal particles (A) are sintered together, whereby the strength and electrical conductivity are increased. It becomes a solid metal with excellent thermal conductivity and exhibits adhesiveness to the contacting substrate or the like. When the heat-sinterable metal fine particles are heat-sinterable silver fine particles, solid silver having excellent strength, electrical conductivity, and heat conductivity is obtained. When the heat-sinterable metal fine particles are heat-sinterable copper fine particles, solid copper having excellent strength, electrical conductivity, and heat conductivity is obtained.

When the paste-like metal fine particle composition (II) of the present invention is heated, the volatile dispersion medium (B) is volatilized, and the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D) are sintered. By bonding, a solid metal or solid metal alloy having excellent strength, electrical conductivity, and thermal conductivity is obtained, and adhesiveness is exhibited on the contacting substrate or the like. When the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D) are heat-sinterable silver fine particles and heat-sinterable silver particles, the strength, electrical conductivity, and heat conductivity are excellent. It becomes solid silver. When the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D) are heat-sinterable copper fine particles and heat-sinterable copper particles, the strength, electrical conductivity, and heat conductivity were excellent. It becomes solid copper. When the heat-sinterable metal fine particles (A) are heat-sinterable silver fine particles and the heat-sinterable metal particles (D) are heat-sinterable other metal particles, the strength, electrical conductivity, and heat conductivity Becomes an excellent solid silver metal alloy. When the heat-sinterable metal fine particles (A) are heat-sinterable copper fine particles and the heat-sinterable metal particles (D) are heat-sinterable other metal particles, the strength, electrical conductivity, and heat conductivity Becomes an excellent solid copper metal alloy.

At this time, the volatile dispersion medium (B) is volatilized, and then the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D) may be sintered. The heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D) may be sintered together with the volatilization. In particular, when the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D) are heat-sinterable silver fine particles and heat-sinterable silver particles, the silver has inherently high strength and extremely high electrical conductivity. Since it has thermal conductivity, the sintered product of the heat-sinterable metal fine particles (A) and the heat-sinterable silver particles (D) also has high strength, extremely high electrical conductivity and heat conductivity. At this time, the volatile dispersion medium is volatilized, and the heating sinterable metal fine particles (A), or the heat sinterable metal fine particles (A) and the heat sinterable metal particles (D) can be sintered. What is necessary is just temperature and it is 70 degreeC or more normally. However, when the temperature exceeds 300 ° C., the volatile dispersion medium evaporates suddenly and the shape of the solid metal (for example, solid silver, solid copper, solid silver metal alloy, solid copper metal alloy) is adversely affected. Since there exists a possibility, it is necessary to be 300 degrees C or less, Preferably it is 250 degrees C or less, More preferably, it is 220 degrees C or less.

Solid metal formed by sintering heat-sinterable metal fine particles (A) coated with a polymer dispersant, or heat-sinterable metal fine particles (A) and heat-sinterable metal particles (D), or As for the electrical conductivity of the solid metal alloy, the volume resistivity is more preferably 1 × 10 ⁻⁵ Ω · cm or less, and more preferably 8 × 10 ⁻⁶ Ω · cm or less. The thermal conductivity is preferably 80 W / m · K or more, and more preferably 100 W / m · K or more. The shape of the solid metal or solid metal alloy is not particularly limited, and examples thereof include a sheet shape, a film shape, a tape shape, a linear shape, a disc shape, a block shape, a spot shape, and an indefinite shape.

When the paste-like fine metal particle composition of the present invention is heated at 70 ° C. or more and 300 ° C. or less, the volatile dispersion medium (B) is volatilized, and the heat sinterable metal fine particles (A) or heat sinterable metal fine particles (A ) And heat-sinterable metal particles (D) are sintered, so that they are excellent in strength, electrical conductivity, and thermal conductivity, and are in contact with metal members such as gold substrates, gold-plated substrates, silver substrates, silver-plated Metal substrates such as metal substrates, copper substrates, palladium substrates, palladium-plated metal substrates, platinum substrates, platinum-plated metal substrates, aluminum substrates, nickel-plated substrates, tin-plated metal substrates, etc., electrodes on metal substrates, electrically insulating substrates, etc. Since it is a solid metal or solid metal alloy that has adhesiveness to metal parts, it is useful for joining metal-based substrates and electronic parts, electronic devices, electric parts, and electric devices that have metal parts. It is for. Such bonding includes bonding of chip components such as capacitors and resistors and circuit boards; bonding of semiconductor chips such as diodes, transistors, memories, ICs, and CPUs to lead frames or circuit boards; cooling semiconductor chips having high heat generation and cooling. The joining with a board is illustrated.

The paste-like metal fine particle composition of the present invention is interposed between a plurality of metal members, and the volatile dispersion medium (B) is volatilized by heating at 70 ° C. or more and 300 ° C. or less, thereby heat-sinterable metal fine particles (A). A plurality of metal members can be firmly bonded together by sintering the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D).

Heat-sinterable metal fine particles (A) produced by heating the paste-like metal fine particle composition of the present invention, or a sintered product of heat-sinterable metal fine particles (A) and heat-sinterable metal particles (D) However, it may be washed with water or an organic solvent. Since each component of the paste-like fine metal particle composition of the present invention has few impurities, it can be easily cleaned.

When the paste-like metal fine particle composition of the present invention is heated, the volatile dispersion medium (B) is volatilized, and the heat-sinterable metal fine particles (A) or heat-sinterable metal fine particles (A) and heat-sinterable When the metal particles (D) are sintered, a solid metal or solid metal alloy having high strength, extremely high electrical conductivity and thermal conductivity is obtained. Therefore, a curable adhesive such as an epoxy resin adhesive, a silicone resin adhesive, a printed wiring board coated with a polyimide resin adhesive, or a primer composition was applied, and then a curable adhesive was applied. By applying the paste-like fine metal particle composition to the printed wiring board and curing at 70 ° C. or more and 300 ° C. or less before the adhesive is cured, it is excellent in wear resistance and adhesion to the substrate. Metal wiring or metal alloy wiring can be formed. Thus, a printed wiring board can be manufactured.
The method for applying the paste-like fine metal particle composition of the present invention is not particularly limited, and includes dispensing, printing (for example, screen printing), metal mask coating, spraying, brushing, and the like. Moreover, a circuit board can be manufactured by mounting a chip or the like on the printed wiring board.

The heating temperature is such that the volatile dispersion medium (B) is volatilized and the heat-sinterable metal fine particles (A) can be sintered together, or the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D) can be sintered. What is necessary is just temperature, and it is 70 degreeC or more normally. However, if it exceeds 300 ° C., the volatile dispersion medium (B) may suddenly evaporate and the shape of the solid metal or solid metal alloy may be adversely affected. The temperature is preferably 250 ° C. or lower, and more preferably 220 ° C. or lower. At this time, the atmosphere may be in the air, but when the heat-sinterable metal fine particles (A), the heat-sinterable metal particles (D) or the material used for the printed circuit board is a metal that is easily oxidized, It may be in an inert gas such as nitrogen or in a forming gas containing hydrogen.

When the paste-like metal fine particle composition of the present invention is heated, the volatile dispersion medium (B) is volatilized, and the heat-sinterable metal fine particles (A) or heat-sinterable metal fine particles (A) and heat-sinterable When the metal particles (D) are sintered, a solid metal or solid metal alloy having high strength, extremely high electrical conductivity and thermal conductivity is obtained. Therefore, the volatile dispersion medium is volatilized by applying the paste-like fine metal particle composition in the form of dots on the electric circuit connecting pad portion on the semiconductor element or the electric circuit connecting end portion on the substrate and heating. Heat-sinterable metal fine particles (A) or heat-sinterable metal fine particles (A) and heat-sinterable metal particles (D) are sintered to form a metal bump or metal on a semiconductor element or substrate. Alloy bumps can be formed. Thus, a bump for connecting an electric circuit can be manufactured.

Here, examples of the semiconductor element include a diode, a transistor, a memory, and a CPU.
Examples of the method for applying the paste-like fine metal particle composition in the form of dots include dropping, dispensing, printing (for example, screen printing), and metal mask application.

The heating temperature is such that the volatile dispersion medium (B) is volatilized and the heat-sinterable metal fine particles (A) can be sintered together, or the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D) can be sintered. What is necessary is just temperature and it is 70 degreeC or more normally. However, if it exceeds 300 ° C., the volatile dispersion medium (B) may suddenly evaporate and the shape of the solid metal or solid metal alloy may be adversely affected. The temperature is preferably 250 ° C. or lower, and more preferably 220 ° C. or lower. At this time, the atmosphere may be in the air, but when the heat-sinterable metal fine particles (A) or the heat-sinterable metal particles (D) are easily oxidized, they are contained in an inert gas such as nitrogen or hydrogen. It may be in forming gas containing.

Since the paste-like metal fine particle composition of the present invention contains a volatile dispersion medium (B), it is preferably stored in a sealed container. When used after long-term storage, it is preferable to use the container after shaking or stirring the container. Refrigerated storage may be performed for the purpose of improving storage stability, and the storage temperature is 10 ° C. or lower, but it is preferable that the volatile dispersion medium is not solidified in the sealed container. When a syringe is used for the sealed container, a small amount can be discharged using a dispenser.

Examples and comparative examples of the present invention will be given. In Examples and Comparative Examples, “parts” means “parts by mass”. Flakes of heat-sinterable metal fine particles or aspect ratio of heat-sinterable metal particles, differential thermal analysis (DTA) of heat-sinterable metal fine particles before and after substitution, carbon atom in paste-like metal fine-particle composition The differential thermal analysis (DTA) in the atmosphere before and after the addition of the carboxylic acid with 2 to 10 in number, the amount of coating on the surface of the heat-sinterable metal fine particles after substitution, and the paste-like metal fine particle composition were heated. The hardness, adhesion strength, volume resistivity, and thermal conductivity of the solid metal or solid metal alloy produced by sintering were measured at 25 ° C. by the following methods.

[Aspect ratio of flaky heat-sinterable metal fine particles or heat-sinterable metal particles]
Flake-shaped heat-sinterable metal fine particles or heat-sinterable metal particles are observed with a scanning electron microscope at a magnification of 5000 times, and 20 heat-sinterable metal fine particles or heat-sinterability in the observed image The major axis and the minor axis in the plane direction of the metal particles are measured, and the average value is set as the plane average particle diameter. Further, the particles are observed at a magnification of 20000 times, and 20 flake-like heat-sinters in the observed image are obtained. The average thickness of the sinterable metal fine particles or the heat-sinterable metal particles was measured to obtain the average thickness. Then, the aspect ratio was calculated by [plane average particle diameter (μm)] / [average thickness (μm)].

[Differential thermal analysis (DTA) of heat-sinterable fine metal particles before and after substitution]
Using a differential thermothermal gravimetric simultaneous measurement device (DTG-60AH type, manufactured by Shimadzu Corporation), when the heat-sinterable metal fine particles are silver fine particles, in the atmosphere, and when the heat-sinterable metal fine particles are copper particles, hydrogen In a forming gas with a gas and nitrogen gas volume ratio of 10:90, the heat-sinterable metal fine particles before and after substitution are raised from room temperature (about 25 ° C.) to 400 ° C. at a rate of temperature rise of 10 ° C./min. A DTA curve was taken after warming.

[Differential thermal analysis (DTA) in the air before and after the addition of the carboxylic acid having 2 to 10 carbon atoms to the paste-like fine metal particle composition]
Using a differential thermothermal gravimetric simultaneous measurement apparatus (DTG-60AH type manufactured by Shimadzu Corporation), the paste-like fine metal particle composition after addition in the atmosphere was added at room temperature (about 25 ° C./min) at a temperature rising rate of 10 ° C./min. C.) to 400 ° C. to obtain a DTA curve.

[Amount of coating on the surface of heat-sinterable metal fine particles after substitution]
Using a differential thermothermal gravimetric simultaneous measurement device (DTG-60AH type, manufactured by Shimadzu Corporation), when the heat-sinterable metal fine particles are silver fine particles, in the atmosphere, and when the heat-sinterable metal fine particles are copper particles, hydrogen In a forming gas with a gas and nitrogen gas volume ratio of 10:90, the heat-sinterable metal fine particles before and after substitution are raised from room temperature (about 25 ° C.) to 400 ° C. at a rate of temperature rise of 10 ° C./min. The weight loss from the initial stage was calculated as the amount of coating.

[Hardness]
A paste-like fine metal particle composition is applied on a polytetrafluoroethylene resin plate having a width of 50 mm, a length of 50 mm, and a thickness of 1.0 mm, using a metal mask having a thickness of 10 mm and a length of 10 mm and a thickness of 10 μm. Then, it was heated in a forced circulation oven at 200 ° C. for 2 hours to form a film-like metal. In addition, when the heat-sinterable metal fine particles were copper fine particles, it was further heated at 200 ° C. for 1 hour in a forming gas having a volume ratio of hydrogen gas and nitrogen gas of 10:90. The hardness of the film-like metal was measured by a method according to JIS Z 2244.

[Adhesive strength]
On a silver substrate (silver purity 99.99%) 1 having a width of 25 mm, a length of 70 mm, and a thickness of 1.0 mm, four openings having a width of 2.5 mm and a length of 2.5 mm are provided at an interval of 10 mm. The paste-like fine metal particle composition is applied using a metal mask having a thickness of 100 μm, and a silver chip (silver purity 99.99%) 3 having a width of 2.5 mm × a length of 2.5 mm × a thickness of 0.5 mm is formed thereon. After mounting, it was heated and bonded in a forced circulation oven at 200 ° C. for 2 hours. In addition, when the heat-sinterable metal fine particles were copper fine particles, it was further heated at 200 ° C. for 1 hour in a forming gas having a volume ratio of hydrogen gas and nitrogen gas of 10:90. The side surface of the silver chip 3 having a width of 2.5 mm, a length of 2.5 mm, and a thickness of 0.5 mm of the test specimen for measuring the adhesive strength thus obtained was pressed at a pressing speed of 23 mm / min by an adhesive strength tester. The bond strength was determined by the load when the joint was sheared. In addition, four said test bodies were measured and let the average value be adhesive strength.

[Volume resistivity]
A paste-like fine metal particle composition is applied on a polytetrafluoroethylene resin plate having a width of 50 mm, a length of 50 mm, and a thickness of 1.0 mm, using a metal mask having a thickness of 10 mm and a length of 10 mm and a thickness of 10 μm. Then, it was heated in a forced circulation oven at 200 ° C. for 2 hours to form a film metal. In addition, when the heat-sinterable metal fine particles were copper fine particles, it was further heated at 200 ° C. for 1 hour in a forming gas having a volume ratio of hydrogen gas and nitrogen gas of 10:90. The volume resistivity (unit: Ω · cm) of the film-like metal was measured by a method according to JIS K 7194.

[Thermal conductivity]
A paste-like fine metal particle composition is applied on a polytetrafluoroethylene resin plate having a width of 50 mm, a length of 50 mm, and a thickness of 1.0 mm using a 2 mm thick metal mask having an opening having a width of 10 mm and a length of 10 mm. And it heated in 200 degreeC forced circulation oven for 2 hours, and it was set as the plate-shaped metal. In addition, when the heat-sinterable metal fine particles were copper fine particles, it was further heated at 200 ° C. for 1 hour in a forming gas having a volume ratio of hydrogen gas and nitrogen gas of 10:90. The thermal conductivity (unit: W / mK) of the plate-like metal was measured by a laser flash method using a thermal constant measuring device.

[Reference example]
Method for producing heat-sinterable metal fine particles (A) in which an organic substance having 5 to 24 carbon atoms having a polar group covering the surface is substituted with a polymer dispersant having an acidic functional group and a basic functional group Is as follows.
In a beaker, 100 parts of heat-sinterable metal fine particles coated with an organic substance having 5 to 24 carbon atoms having a polar group, and a polymer dispersant having an acidic functional group and a basic functional group {when liquid at 25 ° C. Was used as is. In the case of solid at 25 ° C., 100 parts of ethanol (reagent manufactured by Kanto Chemical Co., Ltd. used as a 30% by mass solution) was added, and stirred at 25 ° C. for 5 hours using a magnetic stirrer. Let stand for 10 minutes to remove the supernatant (polymer dispersant or their ethanol solution) as much as possible, add 100 parts of ethanol (a reagent manufactured by Kanto Chemical Co., Inc.), and then use a magnetic stirrer. And stirred at 25 ° C. for 10 minutes. In the same manner, the supernatant was removed as much as possible, then acetone was added again to wash the heat-sinterable metal fine particles in the same manner. This was taken out and air-dried at 25 ° C. for 16 hours.

In the examples and comparative examples, DISPERBYK-2001 (nonvolatile content 46%) and DISPERBYK-2020 (nonvolatile content 70%) sold by Big Chemie Japan Co., Ltd. are co-modified acrylic block copolymers by controlled radical polymerization. This is a polymer solution having an amino group and a phosphate group, and the phosphate group is specifically an acidic phosphate group.
ANTI-TERRA-U (non-volatile content 50%) is a salt of a long-chain polyaminoamide and an acid polymer, specifically a solution of a partial long-chain polyaminoamide salt of a carboxylic acid polymer, which has an aminoamide group and a carboxyl group.
DISPERBYK-140 (non-volatile content 52%) is an alkylammonium salt of an acidic polymer, more specifically, a solution of a partial alkylammonium salt of an acidic polymer having a phosphate group, which has an ammonium base and a phosphate group.
DISPERBYK-106 (91% non-volatile content) is a solution of a polymer salt having an acidic group, more specifically a partial amine salt of a polymer having a phosphate group, which has an amino group and a phosphate group.
DISPERBYK-111 (non-volatile content: 95%) is a solution of a copolymer containing acid groups, more specifically, a solution of a polyester having substantially no amino groups and having phosphate ester groups. Specifically, it is an acidic phosphate group.
DISPERBYK-2022 (non-volatile content 60%) is a solution of a modified acrylic block copolymer by control radical polymerization and has an amino group and substantially no acidic functional group.
In addition, a part... Salt means that a part of a plurality of carboxyl groups or phosphate groups in the molecule is a salt.

[Example 1]
In the production method of the reference example, granular heat-sinterable silver fine particles (average particle diameter of 0.3 mm) produced by a commercially available reduction method and coated with hexanoic acid, which is a 6-carbon organic substance having a polar group on the surface. It is an amphoteric polymer dispersant having 02 μm, the amount of organic matter (note: 2.7% by mass of hexanoic acid and a small amount of organic reducing agent), an amino group and an acidic phosphate group. Using DISPERBYK-2020 (acid value 37 mgKOH / g, amine value 36 mgKOH / g) sold by Big Chemie Japan Co., the hexanoic acid covering the surface of heat-sinterable silver fine particles, amino groups and acidic phosphoric acid Heat-sinterable silver fine particles (A) substituted with a polymer dispersant having an ester group were obtained.

In order to confirm that hexanoic acid was replaced with a polymeric dispersant having an amino group and an acidic phosphate group, a differential thermal analysis was performed on the heat-sinterable silver fine particles before and after substitution. FIG. 1 shows the results of the analysis after substitution, and FIG. 2 shows the analysis results. According to FIG. 1, the exothermic peak due to decomposition of hexanoic acid of the heat-sinterable silver fine particles before substitution is 145.24 ° C., and according to FIG. 2, the polymer of heat-sinterable silver fine particles (A) after substitution The exothermic peak due to the decomposition of the dispersant was 203.01 ° C., and no exothermic peak (145.24 ° C.) due to the decomposition of hexanoic acid in the heat-sinterable silver fine particles before substitution was detected. Therefore, it was confirmed that hexanoic acid was substituted with a polymer dispersant having an amino group and an acidic phosphate group. Moreover, the coating agent amount by the polymer dispersing agent which has an amino group and acidic phosphate group of the heat-sinterable silver fine particle (A) after substitution was 3.2 mass%.

[Example 2]
In the production method of the reference example, granular heat-sinterable silver fine particles (average particle diameter of 0.00) produced by a commercially available reduction method and coated with octanoic acid, which is an organic substance having 8 carbon atoms and having a polar group on the surface. Big Chemie, which is an amphoteric polymer dispersant having an aminoamide group and a carboxyl group, and an organic substance amount (note: the total amount of octanoic acid and a small amount of organic reducing agent is 2.7% by mass) Using ANTI-TERRA-U (acid value 24 mgKOH / g, amine value 19 mgKOH / g) sold by Japan Co., Ltd., octanoic acid covering the surface of heat-sinterable silver fine particles is converted into aminoamide groups and carboxyl groups. Heat-sinterable silver fine particles (A) substituted with a polymer dispersant having the above were obtained.

In order to confirm that octanoic acid was replaced with a polymer dispersant having an aminoamide group and a carboxyl group, differential thermal analysis was performed on the heat-sinterable silver fine particles before and after substitution. An exothermic peak due to decomposition of octanoic acid in the sinterable silver fine particles was not detected. Therefore, it was confirmed that octanoic acid was substituted with a polymer dispersant having an aminoamide group and a carboxyl group. Further, the amount of the coating agent by the polymer dispersant having an aminoamide group and a carboxyl group of the heat-sinterable silver fine particles (A) after the substitution was 2.1% by mass.

[Example 3]
In the production method of the reference example, granular heat-sinterable silver fine particles (average particle diameter of 0.3 mm) produced by a commercially available reduction method and coated with hexanoic acid, which is a 6-carbon organic substance having a polar group on the surface. Big Chemie Japan, which is an amphoteric polymer dispersant having 02 μm, the amount of organic matter (note: 2.7% by mass of hexanoic acid and a small amount of organic reducing agent), and an ammonium base and a carboxyl group DISPERBYK-140 (acid value 73 mgKOH / g, amine value 76 mgKOH / g) sold by Co., Ltd. is used to convert hexanoic acid covering the surface of heat-sinterable silver fine particles into a polymer having ammonium base and phosphate group Heat-sinterable silver fine particles (A) substituted with a dispersant were obtained.

In order to confirm that hexanoic acid was replaced with a polymeric dispersant having an ammonium base and a phosphate group, differential thermal analysis was performed on the heat-sinterable silver fine particles before and after substitution. An exothermic peak due to decomposition of hexanoic acid in the sinterable silver fine particles was not detected. Therefore, it was confirmed that hexanoic acid was replaced with a polymer dispersant having an ammonium base and a phosphate group. Further, the amount of the coating agent by the polymer dispersant having an ammonium base and a phosphate group of the heat-sinterable silver fine particles (A) after the substitution was 2.8% by mass.

[Example 4]
In the production method of the reference example, granular heat-sinterable silver fine particles (average particle diameter of 0.3 mm) produced by a commercially available reduction method and coated with hexanoic acid, which is a 6-carbon organic substance having a polar group on the surface. Bikchemy, which is an amphoteric polymer dispersant having an amino group and a phosphate group, and 02 μm, the amount of organic substances (note: the total amount of hexanoic acid and a small amount of organic reducing agent is 2.7% by mass) Using DISPERBYK-106 (acid value 132 mgKOH / g, amine value 74 mgKOH / g) sold by Japan Co., Ltd., hexanoic acid covering the surface of the heat-sinterable silver fine particles is a high amino acid and phosphate group. Heat-sinterable silver fine particles (A) substituted with a molecular dispersant were obtained.

In order to confirm that hexanoic acid was replaced with a polymeric dispersant having an amino group and a phosphate group, differential thermal analysis was performed on the heat-sinterable silver fine particles before and after substitution. An exothermic peak due to decomposition of hexanoic acid in the sinterable silver fine particles was not detected. Therefore, it was confirmed that hexanoic acid was substituted with a polymer dispersant having an amino group and a phosphoric acid group. Moreover, the coating agent amount by the polymer dispersing agent which has the amino group and phosphoric acid group of the heat-sinterable silver fine particle (A) after substitution was 2.9 mass%.

[Comparative Example 1]
In the production method of the reference example, granular heat-sinterable silver fine particles (average particle diameter of 0.3 mm) produced by a commercially available reduction method and coated with hexanoic acid, which is a 6-carbon organic substance having a polar group on the surface. 02 μm, the amount of organic substances (note: 2.7% by mass of hexanoic acid and a small amount of organic reducing agent) is high and has an acidic phosphate group substantially free of amino groups Using DISPERBYK-111 (acid value 129 mgKOH / g, amine value less than 1 mgKOH / g) sold by Big Chemie Japan Co., Ltd., a molecular dispersant, hexanoic acid covering the surface of heat-sinterable silver fine particles, Heat-sinterable silver fine particles substituted with a polymer dispersant having substantially no amino group and acidic phosphate group were obtained.

Differential thermal analysis of heat-sinterable silver fine particles before and after substitution to confirm that hexanoic acid was replaced with a polymeric dispersant having substantially no amino groups and acidic phosphate groups As a result, no exothermic peak due to decomposition of hexanoic acid in the heat-sinterable silver fine particles before substitution was detected. Therefore, it was confirmed that hexanoic acid was substituted with a polymer dispersant having substantially no amino group and an acidic phosphate group. In addition, the coating amount of the polymer dispersant having substantially no amino group and having an acidic phosphate group in the heat-sinterable silver fine particles after substitution was 3.9% by mass.

[Comparative Example 2]
In the production method of the reference example, granular heat-sinterable silver fine particles (average particle diameter of 0.3 mm) produced by a commercially available reduction method and coated with hexanoic acid, which is a 6-carbon organic substance having a polar group on the surface. 02 μm, the amount of organic substance (note: 2.7% by mass of total amount of hexanoic acid and a small amount of organic reducing agent) and polymer dispersion having amino groups and substantially no acidic functional groups The hexanoic acid coating the surface of heat-sinterable silver fine particles using DISPERBYK-2022 (acid value less than 1 mgKOH / g, amine value 61 mgKOH / g) sold by Big Chemie Japan Co., Ltd. Thus, heat-sinterable silver fine particles substituted with a polymer dispersant having substantially no acidic functional group were obtained.

In order to confirm that hexanoic acid was substituted with a polymeric dispersant having an amino group and substantially no acidic functional group, differential thermal analysis was performed on the heat-sinterable silver fine particles before and after substitution. As a result, no exothermic peak due to decomposition of hexanoic acid in the heat-sinterable silver fine particles before substitution was detected. Therefore, it was confirmed that hexanoic acid was substituted with a polymer dispersant having an amino group and substantially no acidic functional group. In addition, the amount of the coating agent by the polymer dispersant having an amino group and substantially no acidic functional group of the heat-sinterable silver fine particles after the substitution was 3.9% by mass.

[Example 5]
In 25 parts of the heat-sinterable silver fine particles (A) after replacing hexanoic acid prepared in Example 1 with a polymer dispersing agent (DISPERBYK-2020) having an amino group and an acidic phosphate group, a commercially available flaky shape is used. Polygonal, heat-sinterable silver particles (D) 75 parts having an average grain size in the plane direction of 2.0 μm, an aspect ratio of 20 (average thickness of 0.1 μm), and a boiling point of Uniformly, 10 parts of α-terpineol (manufactured by Kanto Chemical Co., Inc.) (B) at 219 ° C. and 2 parts of hexanoic acid (manufactured by Kanto Chemical Co., Ltd.) (C) as a monovalent carboxylic acid having 6 carbon atoms To prepare a pasty silver fine particle composition. This pasty silver fine particle composition could be applied in a good shape without sagging or flowing during application with a metal mask.

In order to confirm the heat-sinterability of this paste-like silver fine particle composition, a differential thermal analysis was performed, and the results are shown in FIG. Comparative Example 3 to be described later is a paste-like silver fine particle composition containing no hexanoic acid (C) in the paste-like silver fine particle composition of Example 5. According to FIG. 3 in Comparative Example 3, hexanoic acid (C ) The exothermic peak due to sintering of the heat-sinterable silver fine particles (A) and heat-sinterable silver particles (D) of the paste-like silver fine particle composition before addition is 261.00 ° C., and hexanoic acid (C) According to FIG. 4 in Example 5 including, the exothermic peak due to sintering of the heat-sinterable silver fine particles (A) and the heat-sinterable silver particles (D) was 251.54 ° C. From this result, the sintering temperature of the heat-sinterable silver fine particles (A) and the heat-sinterable silver particles (D) decreased by 9.46 ° C. by the addition of hexanoic acid (C). Therefore, it was confirmed that the heat-sinterability of the pasty silver fine particle composition was improved by the addition of hexanoic acid (C).

With respect to this pasty silver fine particle composition, the hardness, adhesion strength, volume resistivity, and thermal conductivity of solid silver as a heat-sintered product were measured, and the results are summarized in Table 1. The film-like silver used for the hardness measurement had sufficient hardness to be solid. From the above results, this paste-like silver fine particle composition is useful for producing strong solid silver, useful for strongly joining metal members with good electrical and thermal conductivity, Useful for forming silver wiring with excellent wear resistance, adhesion to substrates, electrical and thermal conductivity, and useful for forming silver bumps on semiconductor devices or substrates all right.

[Comparative Example 3]
In Example 5, a paste-like silver fine particle composition was prepared in the same manner except that hexanoic acid (C) was not added when the paste-like silver fine particle composition was prepared.

In order to confirm the sinterability of this pasty silver fine particle composition, a differential thermal analysis was performed, and the results are shown in FIG. Example 5 described above is a paste-like silver fine particle composition obtained by adding hexanoic acid (C) to the paste-like silver fine particle composition of Comparative Example 3, and the results are shown in FIG. According to FIG. 3 in Comparative Example 3, heat generation due to sintering of the heat-sinterable silver fine particles (A) and the heat-sinterable silver particles (D) of the paste-like silver fine particle composition when hexanoic acid (C) is not included. According to FIG. 4 in Example 5 containing 261.00 ° C. and containing hexanoic acid (C), the heat-sinterable silver fine particles (A) and the heat-sinterable silver particles (D The exothermic peak due to sintering was 251.54 ° C. From this result, the sintering temperature of the heat-sinterable silver fine particles (A) and the heat-sinterable silver particles (D) decreased by 9.46 ° C. by the addition of hexanoic acid (C). That is, it was confirmed that the heat-sinterability of the pasty silver fine particle composition was improved by the addition of hexanoic acid (C).

With respect to this pasty silver fine particle composition, the hardness, adhesion strength, volume resistivity, and thermal conductivity of solid silver as a heat-sintered product were measured, and the results are summarized in Table 4. The film-like silver used for the hardness measurement had a low hardness. Moreover, adhesive strength, electrical conductivity, and thermal conductivity were low.

[Example 6]
In Example 5, instead of the heat-sinterable silver fine particles (A) prepared in Example 1, the hexanoic acid was replaced with a polymer dispersant (DISPERBYK-2020) having an amino group and an acidic phosphate group. Example 2 except that the heat-sinterable silver fine particles (A) prepared in Example 2 were used after substituting octanoic acid with a polymer dispersant (ANTI-TERRA-U) having an aminoamide group and a carboxyl group. In the same manner as in No. 5, a pasty silver fine particle composition was prepared. This pasty silver fine particle composition could be applied in a good shape without sagging or flowing during application with a metal mask.

With respect to this pasty silver fine particle composition, the hardness, adhesion strength, volume resistivity, and thermal conductivity of solid silver as a heat-sintered product were measured, and the results are summarized in Table 1. The film-like silver used for the hardness measurement had sufficient hardness to be solid. From the above results, this paste-like silver fine particle composition is useful for producing strong solid silver, useful for strongly joining metal members with good electrical and thermal conductivity, Useful for forming silver wiring with excellent wear resistance, adhesion to substrates, electrical and thermal conductivity, and useful for forming silver bumps on semiconductor devices or substrates all right.

[Example 7]
In Example 5, instead of the heat-sinterable silver fine particles (A) prepared in Example 1, the hexanoic acid was replaced with a polymer dispersant (DISPERBYK-2020) having an amino group and an acidic phosphate group. The same procedure as in Example 5 was conducted except that the heat-sinterable silver fine particles (A) after substitution were used for the polymer dispersant (DISPERBYK-140) having an ammonium base and a phosphate group prepared in Example 3. A pasty silver fine particle composition was prepared. This pasty silver fine particle composition could be applied in a good shape without sagging or flowing during application with a metal mask.

With respect to this pasty silver fine particle composition, the hardness, adhesion strength, volume resistivity, and thermal conductivity of solid silver as a heat-sintered product were measured, and the results are summarized in Table 1. The film-like silver used for the hardness measurement had sufficient hardness to be solid. From the above results, this paste-like silver fine particle composition is useful for producing strong solid silver, useful for strongly joining metal members with good electrical and thermal conductivity, Useful for forming silver wiring with excellent wear resistance, adhesion to substrates, electrical and thermal conductivity, and useful for forming silver bumps on semiconductor devices or substrates all right.

[Example 8]
In Example 5, instead of the heat-sinterable silver fine particles (A) prepared in Example 1, the hexanoic acid was replaced with a polymer dispersant (DISPERBYK-2020) having an amino group and an acidic phosphate group. Using the heat-sinterable silver fine particles (A) substituted in the polymer dispersant (DISPERBYK-106) having an amino group and a phosphate group, prepared in Example 4, a monovalent carboxylic acid having 6 carbon atoms In the same manner as in Example 5 except that malonic acid (manufactured by Kanto Chemical Co., Inc.) (C), which is a divalent carboxylic acid having 3 carbon atoms, was used instead of hexanoic acid (C) which is an acid. A silver fine particle composition was prepared. This pasty silver fine particle composition could be applied in a good shape without sagging or flowing during application with a metal mask.

With respect to this pasty silver fine particle composition, the hardness, adhesion strength, volume resistivity, and thermal conductivity of solid silver as a heat-sintered product were measured, and the results are summarized in Table 1. The film-like silver used for the hardness measurement had sufficient hardness to be solid. From the above results, this paste-like silver fine particle composition is useful for producing strong solid silver, useful for strongly joining metal members with good electrical and thermal conductivity, Useful for forming silver wiring with excellent wear resistance, adhesion to substrates, electrical and thermal conductivity, and useful for forming silver bumps on semiconductor devices or substrates all right.

[Comparative Example 4]
In Example 5, instead of the heat-sinterable silver fine particles (A) prepared in Example 1, the hexanoic acid was replaced with a polymer dispersant (DISPERBYK-2020) having an amino group and an acidic phosphate group. The heat-sinterable silver fine particles after substitution were used for the polymer dispersant (DISPERBYK-111) prepared in Comparative Example 1 having substantially no amino group and having an acidic phosphate group. Prepared a paste-like silver fine particle composition in the same manner as in Example 5. This pasty silver fine particle composition could be applied in a good shape without sagging or flowing during application with a metal mask.

With respect to this pasty silver fine particle composition, the hardness, adhesion strength, volume resistivity, and thermal conductivity of solid silver as a heat-sintered product were measured, and the results are summarized in Table 4. The film-like silver used for the hardness measurement had a low hardness. Moreover, adhesive strength, electrical conductivity, and thermal conductivity were low.

[Comparative Example 5]
In Example 5, instead of the heat-sinterable silver fine particles (A) prepared in Example 1, the hexanoic acid was replaced with a polymer dispersant (DISPERBYK-2020) having an amino group and an acidic phosphate group. Except for using the heat-sinterable silver fine particles after replacing the hexanoic acid prepared in Comparative Example 2 with a polymer dispersant (DISPERBYK-2022) having an amino group and substantially no acidic functional group. A pasty silver fine particle composition was prepared in the same manner as in Example 5. This paste-like silver fine particle composition had many aggregates of heat-sinterable silver fine particles, and could not be applied in a good shape when applied with a metal mask.

With respect to this pasty silver fine particle composition, the hardness, adhesion strength, volume resistivity, and thermal conductivity of solid silver as a heat-sintered product were measured, and the results are summarized in Table 4. The film-like silver used for the hardness measurement had sufficient hardness to be solid, but the adhesive strength was low.

[Comparative Example 6]
In Example 5, instead of the heat-sinterable silver fine particles (A) prepared in Example 1, the hexanoic acid was replaced with a polymer dispersant (DISPERBYK-2020) having an amino group and an acidic phosphate group. Granular heat-sinterable silver fine particles produced by a commercially available reduction method and coated with hexanoic acid on the surface (average particle size is 0.02 μm, organic matter amount (note: total of hexanoic acid and a small amount of organic reducing agent) A paste-like silver fine particle composition was prepared in the same manner as in Example 5 except that (the amount) was 2.7% by mass). This paste-like silver fine particle composition had many aggregates of heat-sinterable silver fine particles, and could not be applied in a good shape when applied with a metal mask.

With respect to this pasty silver fine particle composition, the hardness, adhesion strength, volume resistivity, and thermal conductivity of solid silver as a heat-sintered product were measured, and the results are summarized in Table 4. The film-like silver used for the hardness measurement had a low hardness. Moreover, adhesive strength, electrical conductivity, and thermal conductivity were low.

[Example 9]
In the production method of the reference example, granular heat-sinterable silver fine particles (average particle diameter is 0.2 μm) produced by a commercially available reduction method and coated with oleic acid, which is an organic substance having 18 carbon atoms having a polar surface. , Big Chemie which is an amphoteric polymer dispersant having an organic group (note: the total amount of oleic acid and a small amount of organic reducing agent is 1.1% by mass) and an amino group and an acidic phosphate group.・ Using DISPERBYK-2020 (acid value 132 mgKOH / g, amine value 74 mgKOH / g) sold by Japan Co., Ltd., oleic acid covering the surface of heat-sinterable silver fine particles, amino groups and acidic phosphates Heat-sinterable silver fine particles (A) substituted with a polymer dispersant having a group were obtained.

In order to confirm that oleic acid was replaced with a polymer dispersant having an amino group and an acidic phosphate group, differential thermal analysis was performed on the heat-sinterable silver fine particles before and after substitution. No exothermic peak due to decomposition of oleic acid in the heat-sinterable silver fine particles was detected. Therefore, it was confirmed that oleic acid was substituted with a polymer dispersant having an amino group and an acidic phosphate group. Moreover, the coating agent amount by the polymer dispersing agent which has the amino group and acidic phosphate group of the heat-sinterable silver fine particle (A) after substitution was 1.2 mass%.

[Example 10]
In Example 5, instead of the heat-sinterable silver fine particles (A) prepared in Example 1, the hexanoic acid was replaced with a polymer dispersant (DISPERBYK-2020) having an amino group and an acidic phosphate group. The procedure was carried out except that the heat-sinterable silver fine particles (A) prepared in Example 9 were replaced with a polymer dispersant (DISPERBYK-2020) having an amino group and an acidic phosphate ester group. A pasty silver fine particle composition was prepared in the same manner as in Example 5. This pasty silver fine particle composition could be applied in a good shape without sagging or flowing during application with a metal mask.

With respect to this pasty silver fine particle composition, the hardness, adhesion strength, volume resistivity, and thermal conductivity of solid silver as a heat-sintered product were measured, and the results are summarized in Table 2. The film-like silver used for the hardness measurement had sufficient hardness to be solid. From the above results, this paste-like silver fine particle composition is useful for producing strong solid silver, useful for strongly joining metal members with good electrical and thermal conductivity, Useful for forming silver wiring with excellent wear resistance, adhesion to substrates, electrical and thermal conductivity, and useful for forming silver bumps on semiconductor devices or substrates all right.

[Example 11]
A boiling point of 219 ° C. was added to 100 parts of the heat-sinterable silver fine particles (A) prepared in Example 1 after replacing hexanoic acid with a polymer dispersant having an amino group and an acidic phosphate group (DISPERBYK-2020). Α-terpineol (manufactured by Kanto Chemical Co., Inc.) (B) 16 parts and hexanoic acid (manufactured by Kanto Chemical Co., Ltd.) (C) 2 parts of monovalent carboxylic acid having 6 carbon atoms are uniformly mixed. Thus, a paste-like silver fine particle composition was prepared. This pasty silver fine particle composition could be applied in a good shape without sagging or flowing during application with a metal mask.

With respect to this pasty silver fine particle composition, the hardness, adhesion strength, volume resistivity, and thermal conductivity of solid silver as a heat-sintered product were measured, and the results are summarized in Table 2. The film-like silver used for the hardness measurement had sufficient hardness to be solid. From the above results, this paste-like silver fine particle composition is useful for producing strong solid silver, useful for strongly joining metal members with good electrical and thermal conductivity, Useful for forming silver wiring with excellent wear resistance, adhesion to substrates, electrical and thermal conductivity, and useful for forming silver bumps on semiconductor devices or substrates all right.

[Example 12]
In Example 5, it is a commercially available flaky silver, heat-sinterable silver having a polygonal shape having an average grain size in the plane direction of 2.0 μm and an aspect ratio of 20 (average thickness is 0.1 μm). Paste silver fine particle composition in the same manner as in Example 5 except that heat-sinterable silver particles (D) having an average particle diameter of 1.0 μm were used instead of particles (D). A product was prepared. This pasty silver fine particle composition could be applied in a good shape without sagging or flowing during application with a metal mask.

With respect to this pasty silver fine particle composition, the hardness, adhesion strength, volume resistivity, and thermal conductivity of solid silver as a heat-sintered product were measured, and the results are summarized in Table 2. The film-like silver used for the hardness measurement had sufficient hardness to be solid. From the above results, this paste-like silver fine particle composition is useful for producing strong solid silver, useful for strongly joining metal members with good electrical and thermal conductivity, Useful for forming silver wiring with excellent wear resistance, adhesion to substrates, electrical and thermal conductivity, and useful for forming silver bumps on semiconductor devices or substrates all right.

[Example 13]
On an FRP (glass fiber reinforced epoxy resin) plate having a thickness of 1.2 mm, an epoxy resin adhesive (product name SW2214, manufactured by Sumitomo 3M Limited) having a thickness of 50 μm and an opening having a width of 1 mm × length of 50 mm is used. It apply | coated using the metal mask, the paste-form silver fine particle composition of Example 5 was printed and applied similarly on the applied epoxy resin adhesive. This FRP plate is heated in a forced circulation oven at 150 ° C for 2 hours to cure the epoxy resin adhesive, and the hexanoic acid is replaced with a polymer dispersant (DISPERBYK-2020) having amino groups and acidic phosphate groups. The heat-sinterable silver fine particles (A) thus obtained were sintered.
When the volume resistivity in the length direction of a silver wiring circuit having a width of 1 mm, a length of 50 mm and a thickness of 50 μm on this printed wiring board was measured, it was 9 × 10 ⁻⁶ Ω · cm, which was practically sufficient conductivity. Had.

[Comparative Example 7]
In Example 5, instead of the heat-sinterable silver fine particles (A) prepared in Example 1, in which hexanoic acid was substituted with a polymer dispersant (DISPERBYK-2020) having an amino group and an acidic phosphate group, Granular heat-sinterable silver fine particles produced by a commercially available reduction method before substitution and coated with hexanoic acid, which is an organic substance having 6 carbon atoms with a polar surface (average particle diameter is 0.02 μm, organic matter amount ( Note: Big Chemie is an amphoteric polymer dispersant that uses 2.7% by mass of hexanoic acid and a trace amount of organic reducing agent) and has an amino group and an acidic phosphate group. A pasty silver fine particle composition was prepared in the same manner as in Example 5 except that 1 part of DISPERBYK-2020 (acid value 37 mgKOH / g, amine value 36 mgKOH / g) sold by Japan Co., Ltd. was added (post-addition). . This paste-like silver fine particle composition had many aggregates of heat-sinterable silver fine particles, and could not be applied in a good shape when applied with a metal mask.

With respect to this pasty silver fine particle composition, the hardness, adhesion strength, volume resistivity, and thermal conductivity of solid silver as a heat-sintered product were measured, and the results are summarized in Table 5. The film-like silver used for the hardness measurement had a low hardness. Moreover, adhesive strength, electrical conductivity, and thermal conductivity were low.

[Comparative Example 8]
In Example 5, instead of the heat-sinterable silver fine particles (A) prepared in Example 1, in which hexanoic acid was substituted with a polymer dispersant (DISPERBYK-2020) having an amino group and an acidic phosphate group, Granular heat-sinterable silver fine particles produced by a commercially available reduction method before substitution and coated with hexanoic acid, which is an organic substance having 6 carbon atoms with a polar surface (average particle diameter is 0.02 μm, organic matter amount ( Note: Big Chemie is an amphoteric polymer dispersant that uses 2.7% by mass of hexanoic acid and a trace amount of organic reducing agent) and has an amino group and an acidic phosphate group.・ Add 1 part of DISPERBYK-2020 (acid value 37 mgKOH / g, amine value 36 mgKOH / g) sold by Japan Co., Ltd. (Chemical Co., Ltd.) (C) Except for not adding, to prepare a paste Jogin particulate composition in the same manner as in Example 5. This paste-like silver fine particle composition had many aggregates of heat-sinterable silver fine particles, and could not be applied in a good shape when applied with a metal mask.

With respect to this pasty silver fine particle composition, the hardness, adhesion strength, volume resistivity, and thermal conductivity of solid silver as a heat-sintered product were measured, and the results are summarized in Table 5. The film-like silver used for the hardness measurement had a low hardness. Moreover, adhesive strength, electrical conductivity, and thermal conductivity were low.

[Comparative Example 9]
In Example 13, an epoxy having a width of 1 mm, a length of 50 mm, and a thickness of 50 μm was used except that the paste-like silver fine particle composition of Comparative Example 4 was used instead of the paste-like silver fine particle composition of Example 5. A resin wiring circuit was produced. As in Example 13, when the volume resistivity in the length direction was measured for an epoxy resin wiring circuit having a width of 1 mm, a length of 50 mm, and a thickness of 50 μm, it was 3 × 10 ⁻⁵ Ω · cm or more, and the conductivity was Was low.

[Example 14]
A copper wiring circuit (width 1 mm, length 50 mm, thickness 30 μm) formed on a 1.2 mm thick FRP plate (glass fiber reinforced epoxy resin) is gold-plated on both ends of the electric circuit 1 mm in length. The paste-like silver fine particle composition of Example 5 was printed and applied in the form of dots using a metal mask having an opening with a width of 1 mm and a thickness of 100 μm. The FRP plate was heated in a forced circulation oven at 150 ° C. for 2 hours to sinter the heat-sinterable silver fine particles (A), thereby producing electric circuit connecting bumps.
When the electric resistance between the electric circuit connecting bumps formed at both ends of the electric circuit was measured, it was less than 0.05Ω, and the electric conductivity was sufficiently practical.

[Example 15]
In the production method of the reference example, granular heat-sinterable silver fine particles (average particle diameter of 0.3 mm) produced by a commercially available reduction method and coated with hexanoic acid, which is a 6-carbon organic substance having a polar group on the surface. It is an amphoteric polymer dispersant having 02 μm, the amount of organic matter (note: 2.7% by mass of hexanoic acid and a small amount of organic reducing agent), an amino group and an acidic phosphate group. Using DISPERBYK-2001 (acid value 19 mgKOH / g, amine value 29 mgKOH / g) sold by Big Chemie Japan Co., the hexanoic acid covering the surface of heat-sinterable silver fine particles, amino groups and acidic phosphoric acid Heat-sinterable silver fine particles (A) substituted with a polymer dispersant having an ester group were obtained.

In order to confirm that hexanoic acid was replaced with a polymeric dispersant having an amino group and an acidic phosphate group, differential thermal analysis was performed on the heat-sinterable silver fine particles before and after substitution. An exothermic peak due to decomposition of hexanoic acid in the heat-sinterable silver fine particles was not detected. Therefore, it was confirmed that hexanoic acid was substituted with a polymer dispersant having an amino group and an acidic phosphate group. In addition, the amount of the coating agent by the polymer dispersant having an amino group and an acidic phosphate group of the heat-sinterable silver fine particles (A) after substitution was 3.0% by mass.

[Example 16]
In Example 5, instead of the heat-sinterable silver fine particles (A) prepared in Example 1, the hexanoic acid was replaced with a polymer dispersant (DISPERBYK-2020) having an amino group and an acidic phosphate group. Except for using the heat-sinterable silver fine particles (A) prepared in Example 15 after replacing the hexanoic acid with a polymer dispersant (DISPERBYK-2001) having an amino group and an acidic phosphate group. In the same manner as in No. 5, a pasty silver fine particle composition was prepared. This pasty silver fine particle composition could be applied in a good shape without sagging or flowing during application with a metal mask.

With respect to this pasty silver fine particle composition, the hardness, adhesion strength, volume resistivity, and thermal conductivity of solid silver as a heat-sintered product were measured, and the results are summarized in Table 2. The film-like silver used for the hardness measurement had sufficient hardness to be solid. From the above results, this paste-like silver fine particle composition is useful for producing strong solid silver, useful for strongly joining metal members with good electrical and thermal conductivity, Useful for forming silver wiring with excellent wear resistance, adhesion to substrates, electrical and thermal conductivity, and useful for forming silver bumps on semiconductor devices or substrates all right.

[Example 17]
In the production method of the reference example, granular heat-sinterable copper fine particles (average particle diameter of 0.02 μm, produced by a reduction method and coated with hexanoic acid, which is a 6-carbon organic substance having a polar group on the surface, are used. Big Chemie, an amphoteric polymer dispersant with an organic group (note: the total amount of hexanoic acid and a small amount of organic reducing agent is 3.5% by mass) and an amino group and an acidic phosphate group Using DISPERBYK-2001 (acid value 19 mgKOH / g, amine value 29 mgKOH / g) sold by Japan Co., Ltd., the hexanoic acid covering the surface of heat-sinterable copper fine particles is converted into amino groups and acidic phosphate groups. Heat-sinterable copper fine particles (A) substituted with a polymer dispersant having the following were obtained.

In order to confirm that hexanoic acid was replaced with a polymeric dispersant having an amino group and an acidic phosphate group, differential thermal analysis was performed on the heat-sinterable copper fine particles before and after substitution. An exothermic peak due to decomposition of hexanoic acid in the heat-sinterable copper fine particles was not detected. Therefore, it was confirmed that hexanoic acid was substituted with a polymer dispersant having an amino group and an acidic phosphate group. Moreover, the coating agent amount by the polymer dispersing agent which has the amino group and acidic phosphate group of the heat-sinterable copper fine particle (A) after substitution was 3.2 mass%.

[Example 18]
In Example 5, instead of the heat-sinterable silver fine particles (A) prepared in Example 1, the hexanoic acid was replaced with a polymer dispersant (DISPERBYK-2020) having an amino group and an acidic phosphate group. The heat-sinterable copper fine particles (A) prepared in Example 17 were used except that the hexanoic acid was replaced with a polymer dispersant (DISPERBYK-2001) having an amino group and an acidic phosphate group. In the same manner as in No. 5, a paste-like copper fine particle composition was prepared. This paste-like copper fine particle composition could be applied in a good shape without sagging or flowing during application with a metal mask.

With respect to the paste-like copper fine particle composition, the hardness, adhesion strength, volume resistivity, and thermal conductivity of the solid copper-silver alloy that is a heat-sintered product were measured, and the results are summarized in Table 3. The film used for the hardness measurement had sufficient hardness to be solid. From the above results, this paste-like copper fine particle composition is useful for producing a solid solid copper-silver alloy, and useful for strongly joining metal members with good electrical and thermal conductivity. Useful for forming copper-silver alloy wiring with excellent wear resistance, adhesion to the substrate, electrical conductivity and thermal conductivity, and forming copper-silver alloy bumps on the semiconductor element or on the substrate I found it useful.

The heat-sinterable metal fine particles produced by the production method of the present invention are useful as the main agent of the paste-like metal fine particle composition.
The paste-like fine metal particle composition of the present invention is useful for the production of a solid metal or a solid metal alloy or the joining of metal members.
The solid metal or solid metal alloy production method and metal member joining method of the present invention include various electronic components such as resistors and capacitors, formation of electrodes of various display elements, formation of a conductive coating for electromagnetic wave shielding, Bonding chip components such as capacitors, resistors, diodes, memories, and arithmetic elements (CPUs) to the substrate, forming electrodes for solar cells, multilayer ceramic capacitors, multilayer ceramic inductors, multilayer ceramic actuators, etc. It is useful for forming electrodes, forming conductive circuits on a printed circuit board, and the like.
The method for producing a wiring board of the present invention is useful for efficiently producing a printed wiring board having metal wiring or metal alloy wiring.
The method for producing a bump for connecting an electric circuit of the present invention is useful for efficiently producing a metal or metal alloy bump on a semiconductor element or a substrate.

A Bond strength test specimen 1 Silver substrate 2 Paste-like metal fine particle composition (solid metal after heating and sintering)
3 Silver chip

Claims (20)

The carbon particles of the heat-sinterable metal fine particles having an average particle diameter of 0.010 μm to 0.2 μm and having a surface coated with an aliphatic carboxylic acid having 5 to 24 carbon atoms or a polyvalent aromatic carboxylic acid. Heat-sinterable metal fine particles after substitution with a polymer dispersant having an acidic functional group that is a carboxyl group, a phosphoric acid group or an acidic phosphoric ester group and a basic functional group that is an amino group or an ammonium base Of the heat-sinterable metal fine particles, wherein the heat-sinterable metal fine particles are replaced until the exothermic peak due to the thermal decomposition of the carboxylic acid disappears in the differential thermal analysis chart in the atmosphere Method. The method for producing heat-sinterable metal fine particles according to claim 1, wherein the polymer dispersant has an acid value and an amine value of 5 to 300 mgKOH / g, respectively. 2. A part of a carboxyl group, a phosphate group or an acidic phosphate group in a molecule is salified and / or a part of an amino group in a molecule is salified. Or the manufacturing method of the heat-sinterable metal fine particle of Claim 2. The method for producing heat-sinterable metal fine particles according to any one of claims 1 to 3, wherein the polymer dispersant comprises a synthetic polymer. The method for producing heat-sinterable metal fine particles according to claim 4, wherein the synthetic polymer is a vinyl polymer or a condensation polymer. The heat-sinterable metal fine particles according to any one of claims 1 to 5, wherein the heat-sinterable metal fine particles are heat-sinterable silver fine particles or heat-sinterable copper fine particles. Production method. The shape of the heating sinterable metal particles spherical, a granular or flaky, the surface of the heat sinterable metal particles, characterized in that that have been coated with an aliphatic carboxylic acid having a carbon atom number of 5-24, wherein The manufacturing method of the heat-sinterable metal fine particle of any one of Claims 1-6. (A) Heat-sinterable metal fine particles having an average particle diameter of 0.010 μm to 0.2 μm and having a surface coated with an aliphatic carboxylic acid having 5 to 24 carbon atoms or a polyvalent aromatic carboxylic acid Heat-sinterability after substitution of the carboxylic acid with a polymer dispersant having an acidic functional group which is a carboxyl group, a phosphoric acid group or an acidic phosphoric ester group and a basic functional group which is an amino group or an ammonium base In the differential thermal analysis chart for the fine metal particles in the atmosphere, the heat-sinterable metal fine particles substituted until the exothermic peak due to the thermal decomposition of the carboxylic acid of the heat-sinterable metal fine particles before substitution disappears, (B) It consists of a volatile dispersion medium having a boiling point of 70 ° C. to 300 ° C. and (C) a monovalent or divalent carboxylic acid having 2 to 10 carbon atoms, and the volatile dispersion medium (B) is volatilized by heating. Heating Sexual metal microparticles (A) each other, characterized in that the sintering paste metal fine particle composition. Heat-sinterable metal fine particles (A), volatile dispersion medium (B), carboxylic acid (C), and (D) heat-sinterable metal particles having an average particle size of more than 0.2 μm and 10 μm or less, The paste form according to claim 8, wherein the volatile dispersion medium (B) is volatilized by heating and the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D) are sintered. Metal fine particle composition. 10. The paste-like fine metal particle composition according to claim 8, wherein the polymer dispersant has an acid value and an amine value of 5 to 300 mgKOH / g, respectively. 9. A part of carboxyl group, phosphate group or acidic phosphate group in the molecule is salified and / or a part of amino group in the molecule is salified. The paste-like metal fine particle composition according to claim 9 or 10. The paste-like fine metal particle composition according to any one of claims 8 to 11, wherein the polymer dispersant is made of a synthetic polymer. The heat-sinterable metal fine particle composition according to claim 12, wherein the synthetic polymer is a vinyl polymer or a condensation polymer. The paste-like metal fine particles according to any one of claims 8 to 13, wherein the heat-sinterable metal fine particles (A) are heat-sinterable silver fine particles or heat-sinterable copper fine particles. Composition. The shape of the heat-sinterable metal fine particles (A) is spherical, granular or flaky, and the surface of the heat-sinterable metal fine particles (A) is coated with an aliphatic carboxylic acid having 5 to 24 carbon atoms, The paste-like metal fine particle composition according to any one of claims 8 to 14, wherein the shape of the heat-sinterable metal particles (D) is spherical, granular or flaky. The paste-like metal fine particle composition according to any one of claims 8 to 15 is heated at 70 ° C or higher and 300 ° C or lower to volatilize the volatile dispersion medium and thereby heat-sinterable metal fine particles. (A) Sinter metal heat-sinterable metal particles (A) and heat-sinterable metal particles (D), and the volume resistivity after sintering is 1 × 10 ⁻⁵ Ω · cm or less, and A method for producing a solid metal or solid metal alloy, wherein the thermal conductivity is 80 W / m · K or more. The volatile dispersion medium (B) by interposing the paste-like fine metal particle composition according to any one of claims 8 to 15 between a plurality of metal members and heating at 70 ° C to 300 ° C. Sinter the heat-sinterable metal fine particles (A) or heat-sinterable metal fine particles (A) and heat-sinterable metal particles (D), and join a plurality of metal members together A method for joining metal members, which is characterized. The metal member joining method according to claim 17, wherein the metal member is a metal substrate or a metal portion of an electronic component. Volatile dispersion by applying the paste-like fine metal particle composition according to any one of claims 8 to 15 on a substrate coated with an adhesive and heating at 70 ° C to 300 ° C. The medium (B) is volatilized and the heat-sinterable metal fine particles (A) or the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles (D) are sintered, and metal wiring or A method for producing a printed wiring board, comprising forming a metal alloy wiring. The paste-like fine metal particle composition according to any one of claims 8 to 15 is applied in a dot shape to an electric circuit connecting pad portion on a semiconductor element or an electric circuit connecting electrode portion on a substrate, By heating at 70 ° C. or more and 300 ° C. or less, the volatile dispersion medium (B) is volatilized, and the heat-sinterable metal fine particles (A) or the heat-sinterable metal fine particles (A) and the heat-sinterable metal particles ( D) is sintered to form a metal bump or a metal alloy bump on a semiconductor element or a substrate.

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