JP2010131669A - Joining agent for metal component, method of producing metal component joined article, metal component joined article, and method of manufacturing bump for electric circuit connection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paste-like joining agent for a metal component to be a porous sintered compact for adhering to the contacted metal component in which metal particles are sintered when heated, and a method of manufacturing a bump for electric circuit connection excellent in adhesiveness to a substrate electrode, heat-resistant processability, and electrical conductivity. <P>SOLUTION: A paste-like material includes (A) metal particles having an average particle diameter (median size D50) of 0.1-50 μm and melting point of ≥400°C, and being heat sinterable, and (B) liquid flux, and forms the joining agent for the metal component which becomes the porous sintered compact having adhesiveness to the contacted metal component in which the metal particles (A) are sintered, when heated at 70-400°C. The method of producing the metal component joined article is constituted by heating the joining agent stood between the metal components at 70-400°C. The metal component joined article is constituted in which a plurality of metal components are joined by the porous sintered compact having porosity of 5-50 area%, melting point of >400°C, and volume resistivity of ≤1×10<SP>-2</SP>Ω cm. The method of manufacturing the bump for electric circuit connection is constituted by heating the joining agent. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention is a paste made of heat-sinterable metal particles and a flux, which is sintered by heating to become a porous sintered product having a melting point equivalent to that of the metal particles. Manufacturing method of metal member joined body by joining agent, metal member joined body in which metal member is joined by porous sintered product of metal, and bump for electric circuit connection using joining agent for metal member It relates to a manufacturing method.

Electrically conductive / thermally conductive paste made by dispersing metal powders such as silver, copper, and nickel in a liquid thermosetting resin composition is cured by heating to form an electrically conductive / thermally conductive film. . Therefore, formation of an electrically conductive circuit on a printed circuit board; formation of electrodes of various electronic components such as resistors and capacitors and various display elements; formation of an electrically conductive film for electromagnetic wave shielding; capacitor, resistor, diode, memory, Adhesion of chip parts such as arithmetic elements (CPUs) to substrates; formation of solar cell electrodes, especially formation of solar cell electrodes that cannot be processed at high temperatures due to the use of amorphous silicon semiconductors; multilayer ceramic capacitors, multilayer It is used to form external electrodes for chip-type ceramic electronic components such as ceramic inductors and multilayer ceramic actuators.

2. Description of the Related Art In recent years, chip components have increased in performance, and the amount of heat generated from the chip components has increased, and improvement in thermal conductivity as well as electrical conductivity is required. Therefore, it tries to improve electrical conductivity and thermal conductivity by increasing the content of metal particles as much as possible. However, when it does so, there exists a problem that the viscosity of a paste rises and workability | operativity falls remarkably.

In order to solve such a problem, the present inventors, when heated, the paste-like silver composition composed of silver powder and a volatile dispersion medium volatilizes the volatile dispersion medium and sinters the silver powder, An international application was filed for finding solid silver having extremely high electrical conductivity and thermal conductivity, and useful for joining metal members and forming conductive circuits {Patent Document 1 (WO2006 / 126614) Patent Document 2 (WO2007 / 034833)}.
However, the present inventors have noticed that a passivated silver powder having a stable surface state has a problem of poor sinterability.

In addition, the present inventors have found that when a paste-like copper composition comprising copper powder and a volatile dispersion medium is heated in a reducing gas atmosphere, the volatile dispersion medium is volatilized and the copper powder is sintered. An international application was filed for finding solid copper having high electrical conductivity and thermal conductivity, and useful for joining metal members and forming conductive circuits {Patent Document 3 (PCT / JP2008 / 002045). However, the present inventors have found that a passivated silver-copper powder having a stable surface state has a problem of poor sinterability.

On the other hand, in Patent Document 4 (Japanese Patent Laid-Open No. 2002-224884), metal particles made of a metal (for example, silver) having a melting point higher than that of solder are added to a flux made of a resin (for example, rosin resin). The soldering flux and the base electrode formed on the substrate are made of flux (for example, rosin resin) and metal (for example, silver) powder (0.1 to 10 μm diameter) having a melting point higher than that of solder. A step of printing a soldering flux, a step of mounting a solder (for example, eutectic solder (Sn 60%, Pb 40%)) ball on a base electrode on which the soldering flux is printed, and the solder ball by heat treatment And a method for forming a solder bump comprising the step of melting the solder. By heat treatment at a temperature equal to or higher than the melting temperature of the solder constituting the solder ball (about 180 ° C. for eutectic solder), the silver particles contained in the soldering flux easily diffuse into the molten solder, and the melting point of the solder is reduced. It is stated that it is slightly higher. When a metal member is placed on such a solder bump and heat-treated, the metal member is bonded onto the base electrode, but since the melting point of the solder is not high, it melts at the heat treatment temperature of the subsequent process and has a strength. There is a problem that is low.

WO2006 / 126614 WO2007 / 034833 PCT / JP2008 / 002045 Japanese Patent Application Laid-Open No. 2002-224884

As a result of earnest research to develop a paste-like bonding agent that does not have the above-mentioned problems, the present inventors have found that the particle size and melting point of the metal particles, and the liquid dispersion medium used for pasting the sinterability and sintering of the metal particles. The present inventors have found that the solid state produced by the sintering affects the sintering state and melting point of the solid metal, the bonding strength of the bonded body, and the electrical conductivity, thereby completing the present invention. The object of the present invention is to sinter metal particles by heating to form a porous sintered product having a melting point equivalent to that of the metal particles, and to adhere to the metal member that has been in contact during sintering, heat resistance Bonding agent for metal members with excellent electrical conductivity; Method for producing a bonded metal member in which metal members are firmly bonded with good electrical conductivity; Metal with excellent bonding strength, heat resistance, and electrical conductivity An object of the present invention is to provide a method for producing a bump for connecting an electric circuit excellent in adhesiveness to a base electrode, heat resistance, and electrical conductivity.

The purpose of this is “[1] (A) metal particles whose average particle diameter (median diameter D50) is greater than 0.1 μm and less than 50 μm, melting point is higher than 400 ° C. and heat-sinterable, and (B) liquid flux. The metal particles (A) are sintered together by heating at 70 ° C. or more and 400 ° C. or less, and have a melting point equivalent to that of the metal particles (A). A bonding agent for a metal member, which is a porous sintered product having adhesion to the metal member in contact.
[2] The bonding agent for metal members according to [1], wherein the metal particles (A) are produced by an atomizing method and have a metal oxide layer on the surface.
[3] The metal particles (A) are silver particles or copper particles, and the melting point of the metal particles (A) and the porous sintered product is higher than 600 ° C., and the volume resistivity of the silver particles and the porous sintered product is Or 1 × 10 ⁻⁴ Ω · cm or less, and the volume resistivity of the copper particles and the porous sintered product thereof is 1 × 10 ⁻² Ω · cm or less, [1] or [2 ] The joining agent for metal members as described in the above.
[4] The liquid flux (B) comprises (a) a liquid product comprising rosin or a derivative thereof and (d) a solvent, (a) a rosin or a derivative thereof, (b) an oxide film removal activator, and (d) a solvent. A liquid comprising (a) rosin or a derivative thereof and (c) a thixotropic agent and (d) a solvent, (a) a rosin or a derivative thereof and (b) an oxide film removing activator and (c) A liquid material comprising a thixotropic agent and (d) a solvent, (b) a liquid material comprising an oxide film removal activator and (d) a solvent, or (b) an oxide film removal activator and (c) a thixotropic agent. And (d) a bonding agent for metallic members according to [1], [2] or [3], which is a liquid material comprising a solvent.
[5] The bonding agent for metal members according to [1], [2] or [3], wherein the porosity in the cross section of the porous sintered product is 5 to 50% by area.
[5-1] The bonding agent for metallic members according to [4], wherein the porosity in the cross section of the porous sintered product is 5 to 50% by area. Is achieved.

The purpose of this is “[6] (A) metal particles whose average particle diameter (median diameter D50) is greater than 0.1 μm and less than 50 μm, melting point is higher than 400 ° C. and heat-sinterable, and (B) liquid flux By interposing a paste-like material made of a plurality of metal members and heating at 70 ° C. or more and 400 ° C. or less, the metal particles (A) are sintered to have a melting point equivalent to that of the metal particles (A). A method for producing a metal member assembly, comprising a porous sintered product, wherein a plurality of metal members are joined to each other.
[7] The method for producing a metal member assembly according to [6], wherein the metal particles (A) are produced by an atomizing method and have a metal oxide layer on the surface.
[8] The metal particles (A) are silver particles or copper particles, the metal particles (A) and the melting point thereof are higher than 600 ° C., and the volume resistivity of the silver particles and the porous sintered product thereof is 1 × 10 ^−4. The metal product according to [6] or [7], wherein the volume resistivity of the copper particles and the porous sintered product thereof is 1 × 10 ⁻² Ω · cm or less. Manufacturing method of member assembly.
[9] The liquid flux (B) comprises (a) a liquid material comprising rosin or a derivative thereof and (d) a solvent, (a) a rosin or a derivative thereof, (b) an oxide film removal activator, and (d) a solvent. A liquid comprising (a) rosin or a derivative thereof and (c) a thixotropic agent and (d) a solvent, (a) a rosin or a derivative thereof and (b) an oxide film removing activator and (c) A liquid material comprising a thixotropic agent and (d) a solvent, (b) a liquid material comprising an oxide film removal activator and (d) a solvent, or (b) an oxide film removal activator and (c) a thixotropic agent. [6], [7] or [8], The method for producing a metal member assembly according to [6], [7] or [8], wherein
[10] The method for producing a metal member bonded body according to [6], [7] or [8], wherein the porosity of the porous sintered body in the cross section is 5 to 50% by area.
[10-1] The method for producing a metal member assembly according to [9], wherein the porosity in the cross section of the porous sintered product is 5 to 50% by area. Is achieved.

The object is to obtain a plurality of metal members obtained by the production method described in [11] [6], wherein the porosity in the cross section is 5 to 50% by area, the melting point is higher than 400 ° C., and the volume resistance A metal member joined body characterized by being joined by a porous sintered product of heat-sinterable metal particles (A) having a rate of 1 × 10 ⁻² Ω · cm or less.
[12] The metal particles (A) are silver particles or copper particles, the metal particles (A) and the melting point thereof are higher than 600 ° C., and the volume resistivity of the silver particles and the porous sintered product thereof is 1 × 10 ^−4. The volume resistivity of the copper particles and the porous sintered product thereof is 1 × 10 ⁻² Ω · cm or less, and the shear bonding strength at 250 ° C. of the metal member assembly is 5 MPa or more. The metal member joined body according to [11], which is characterized in that it exists.
[13] The metal member assembly according to [11] or [12], wherein the metal member is a metal substrate or an electronic component having a metal portion. Is achieved.

The purpose of this is to apply the bonding agent for a metal member according to any one of [14] [1] to [4] to an electric circuit connecting pad portion on a semiconductor element or an electric circuit connecting electrode portion on a substrate. The metal particles are applied to each other and heated at 70 ° C. or more and 400 ° C. or less to sinter the metal particles to form metal bumps on the semiconductor element or the substrate. Bump manufacturing method.
[14-1] The metal member bonding agent according to [5] 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, and is 70 ° C. or higher and 400 ° C. A method of manufacturing a bump for connecting an electric circuit, characterized in that the metal particles are sintered together by heating to form metal bumps on a semiconductor element or a substrate. Is achieved.

The bonding agent for a metal member of the present invention is a porous sintered product having a melting point equivalent to that of the metal particles (A) by sintering the metal particles (A) by heating at 70 ° C. or more and 400 ° C. or less. Thus, the electrical conductivity is excellent, and the adhesion to the metal member that has been in contact during sintering and the heat resistance are excellent.
According to the method for producing a metal member assembly of the present invention, it is possible to easily and efficiently produce a joined body in which a plurality of metal members are firmly bonded with good electrical conductivity and heat resistance.
The metal member joined body of the present invention is useful as an electronic component or the like in which the metal member has a metal-based substrate or a metal portion because the joint strength, heat resistance, and electrical conductivity of the joint portion are excellent.
According to the method for manufacturing an electric circuit connecting bump of the present invention, an electric circuit connecting bump excellent in adhesiveness to a base electrode, heat resistance, and electric conductivity can be easily and efficiently manufactured.

It is a cross-section part enlarged photograph of the porous sintered compact of the silver particle manufactured by the atomizing method. It is a top view of the test body A for shear bond strength measurement in an Example. The silver substrate 1 and the silver chip 3 are joined by solid silver or solid copper 2 which is a heat-sintered product of silver particles or copper particles. It is a side view of the XX line direction in FIG.

The metal member bonding agent of the present invention comprises (A) metal particles having an average particle diameter (median diameter D50) of greater than 0.1 μm and less than or equal to 50 μm, a melting point of greater than 400 ° C. and heat-sinterability; It is a paste-like material composed of flux, and when heated at 70 ° C. or higher and 400 ° C. or lower, the metal particles (A) are sintered to have a melting point equivalent to that of the metal particles (A), and sintered. It becomes the porous sintered material which has adhesiveness to the metal member which contacted on the way.

The average particle diameter of the metal particles (A) is an average particle diameter (median diameter D50) of primary particles obtained by a laser diffraction / scattering particle size distribution measurement method. When the average particle diameter (median diameter D50) exceeds 50 μm, the heat-sinterability between metal particles becomes small, and it is difficult to obtain excellent bonding strength and electrical conductivity. Therefore, the one where an average particle diameter is smaller is more preferable, and it is especially preferable that it is 10 micrometers or less. However, in the case of 0.1 μm or less, which is a so-called nano-size, the surface activity is too strong and the storage stability of the paste-like bonding agent may be lowered. Therefore, it is necessary to exceed 0.1 μm, and preferably 0.1 μm. They are 2 micrometers or more and 10 micrometers or less, More preferably, they are 0.7 micrometers or more and 5 micrometers or less.
The median diameter D50 is also referred to as a laser diffraction method 50% particle size (see Japanese Patent Application Laid-Open No. 2003-55701) or a volume cumulative particle size D50 (see Japanese Patent Application Laid-Open No. 2007-84860).

The laser diffraction / scattering particle size distribution measurement method is a method of irradiating a metal beam with a laser beam and measuring the intensity of the diffracted light or scattered light emitted in various directions depending on the size of the metal particle. This is a general-purpose measurement method for determining the particle size of particles. 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. In the case where the aggregation of the metal particles is strong, it is preferably measured after being dispersed in a primary particle state by a homogenizer.

The material of the metal particles (A) is solid at room temperature, has a melting point higher than 400 ° C., and can be easily sintered by heating. Gold, silver, copper, palladium, nickel, tin, aluminum, and each of these metals These alloys are exemplified, and further, metal compounds are exemplified.
Among these materials, the melting point is 600 ° C. or higher, and silver, silver alloy, copper, and copper alloy are preferable, and silver and copper are particularly preferable in view of heat sinterability and conductivity of the heat sintered product. The silver particles may have a part of the surface or inside thereof that may be silver oxide or silver peroxide, and the entire surface may be silver oxide or silver peroxide. The copper particles may have copper oxide on the surface or part of the inside, or the entire surface may be copper oxide.

The metal particles (A) are usually composed of a single material, but may be a mixture of particles of a plurality of materials.
The metal particles (A) are metal (for example, copper, nickel or aluminum) particles whose surfaces are plated with these metals (for example, silver), and resins whose surfaces are plated with these heat-sinterable metals (for example, silver) ( For example, epoxy resin or polyether sulfone resin) particles may be used.

The shape of the metal particle (A) is not particularly limited as long as it has heat sinterability, and is spherical, granular, flaky (flaky), acicular, angular, dendritic, irregular, teardrop, fiber The shape is exemplified (see JIS Z2500: 2000). Further examples include a plate shape, an ultrathin plate shape, a hexagonal plate shape, a columnar shape, a rod shape, a porous shape, a lump shape, a spongy shape, a rounded shape, a round shape, an elliptical sphere shape, a grape shape, a spindle shape, and a substantially cubic shape.
The shape is preferably spherical, granular, or flaky (flaky) from the viewpoint of easily forming a porous sintered product.
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 the spherical coefficient) is in the range of 1.0 to 1.2. 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. No matter the shape, the particle size distribution is not limited.

The production method of the metal particles (A) is not limited, and examples include a reduction method, a pulverization method, an electrolysis method, an atomization method, a heat treatment method, and a combination thereof, but reduction that makes it easy to obtain granular or spherical particles Or the atomizing method.
Many methods for producing silver particles by the reduction method have been proposed. Usually, a silver oxide solution is prepared by adding an aqueous sodium hydroxide solution to an aqueous silver nitrate solution, and an aqueous solution of a reducing agent such as formalin is added to the silver oxide solution. It is manufactured by reducing to a silver particle dispersion, filtering the dispersion, washing the filtration residue with water, and drying.
As described in JP-A-59-116203, the copper particles obtained by the reduction method are usually dried by being brought into contact with a copper sulfate aqueous solution and a hydrazine aqueous solution to reduce and precipitate copper powder, washing with pure water, and drying. Manufactured. As described in JP-A-9-137207, metal particles obtained by the atomization method are produced by spraying a high-pressure inert gas onto molten metal flowing down from a metal melting tank and rapidly solidifying the molten metal. . In Japanese Patent Laid-Open No. 5-156321, metal powder is produced by an atomizing method using water instead of an inert gas.

The metal particles (A) thus produced are usually granular or spherical, but may be coated with an organic substance to prevent aggregation and / or oxidation. Examples of such organic substances include high and intermediate fatty acids such as caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid; Examples include medium fatty acid esters, high and medium fatty acid derivatives such as high and medium fatty acid amides; and high and medium alkylamines such as dodecylamine. The surface of the metal particles (A) may be either water-repellent or hydrophilic.

The amount of the organic substance on the surface of the metal particles (A) is 5% by weight or less, preferably 2% by weight or less in terms of the sinterability of the metal particles. Here, the amount of organic matter can be measured by a usual method. For example, a method of measuring weight loss when the metal particles (A) are heated to 500 ° C. in an inert gas is exemplified.

The metal particles (A) thus obtained are in contact with the liquid flux (B) when sintered at a temperature of 70 ° C. or more and 400 ° C. or less, and in the course of heating and sintering. The adhesiveness to the metal member that has been used and the electrical conductivity of the solid metal formed by sintering are excellent.

The metal member bonding agent of the present invention is a mixture of metal particles (A) and liquid flux (B), and the powdered metal particles (A) are made into a paste by the action of the liquid flux (B). By making it into a paste, it can be discharged in a thin line from a cylinder or nozzle, and printing with a metal mask becomes easy. The liquid flux (B) becomes a paste by mixing with powdered metal particles (A) at an appropriate ratio.

The liquid flux (B) dissolves and removes oxides from the surfaces of the metal particles (A) and the metal member, facilitates the heat sintering of the metal particles (A), and heat-fires the metal particles (A). Improves the adhesion between the joint and the metal member.

In the bonding agent for metal members of the present invention, a conventionally known flux at a normal temperature can be used. Such a liquid flux is usually composed of at least a base resin and a solvent, and is optionally composed of an oxide film removing activator, a thixotropic agent, and the like. As the liquid flux (B), (a) a liquid material comprising rosin or a derivative thereof and (d) a solvent, (a) a liquid material comprising a rosin or a derivative thereof, (b) an oxide film removal activator and (d) a solvent. (A) rosin or derivative thereof, (c) thixotropic agent, and (d) liquid product comprising (d) solvent, (a) rosin or derivative thereof, (b) oxide removal agent and (c) thixotropic agent And (d) a liquid comprising a solvent, (b) a liquid comprising an oxide film removal activator and (d) a solvent, and (b) an oxide film removal activator and (c) a thixotropic agent (d ) A liquid material comprising a solvent is exemplified.

Examples of the base resin include rosin, rosin derivative (a), and synthetic resin. Examples of rosins include gum rosin, tall rosin and wood rosin. Heat treated rosin, polymerized rosin, modified rosin (eg, acrylated rosin, hydrogenated rosin, formylated rosin, rosin ester, rosin modified maleic resin, rosin modified phenolic resin, rosin modified alkyd resin), low softening A point rosin is exemplified. Acrylic rosin is obtained by subjecting various rosins to an addition reaction of acrylic acid or its ester or methacrylic acid or its ester. The low softening point rosin can be obtained by heating various rosins at 250 to 300 ° C. for several hours in an inert gas atmosphere.

Examples of synthetic resins include aliphatic polyamide resins, acrylic resins, ethylene-acrylic copolymers, styrene-maleic acid resins, epoxy resins, and polyurethane resins. The aliphatic polyamide resin is an aliphatic polyamide resin obtained by a polycondensation reaction between an aliphatic dicarboxylic acid having 2 to 21 carbon atoms and an aliphatic diamine, and has a softening point of 80 to 150 ° C, or 2 to 2 carbon atoms. A polyamide resin obtained by a polycondensation reaction of 21 dimer acid and an aliphatic diamine, preferably having a softening point of 80 to 150 ° C.
The base resin may be a combination of different rosins or derivatives thereof, or a combination of rosin or derivatives thereof and a synthetic resin.
The base resin is preferably liquid at normal temperature, but may be solid as long as it melts at about 35 to 150 ° C. or can be dissolved in a solvent.

The solvent (d) is a necessary component when the base resin is in a solid state at room temperature or in a viscous liquid state. As solvent (d), ethyl alcohol, propyl alcohol, butyl alcohol, pentyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, ethylene glycol monomethyl ether (methyl cellosolve, methyl carbitol), ethylene glycol monoethyl Ether (ethyl cellosolve, ethyl carbitol), ethylene glycol monopropyl ether (propyl cellosolve, propyl carbitol), ethylene glycol monobutyl ether (butyl cellosolve, butyl carbitol), propylene glycol monomethyl ether, methyl methoxybutanol, α-terpineol, β -Terpineol, hexylene glycol, benzyl alcohol, 2-phenylethyl Alcohols such as alcohol, isopalmityl alcohol, isostearyl alcohol, lauryl alcohol, ethylene glycol, propylene glycol, glycerin; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol (4-hydroxy-4-methyl- 2-pentanone), 2-octanone, isophorone (3,5,5-trimethyl-2-cyclohexen-1-one), ketones such as dibutyl ketone (2,6-dimethyl-4-heptanone); ethyl acetate, Butyl acetate, disisobriz adipate, diethyl phthalate, dibutyl phthalate, acetoxyethane, methyl butyrate, methyl hexanoate, methyl octoate, methyl decanoate, methyl cellosolve acetate, propylene glycol Esters such as monomethyl ether acetate, 1,2-diacetoxyethane, tributyl phosphate, tricresyl phosphate, tripentyl phosphate; tetrahydrofuran, dipropyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, propylene glycol Ethers such as dimethyl ether, ethoxyethyl ether, 1,2-bis (2-diethoxy) ethane, 1,2-bis (2-methoxyethoxy) ethane; ester ethers such as acetic acid 2- (2 butoxyethoxy) ethane; Ether alcohols such as 2- (2-methoxyethoxy) ethanol; toluene, xylene, n-paraffin, isoparaffin, dodecylbenzene, turpentine oil, kerosene, light oil, etc. Examples include hydrocarbons; nitriles such as acetonitrile and propionitrile; amides such as acetamide and N, N-dimethylformamide; low molecular weight volatile silicone oil and volatile organic modified silicone oil. The solvent (d) preferably has a boiling point of 50 to 300 ° C. at normal pressure.

The content of the solvent (d) is usually 20 to 99.99% by weight, preferably 20 to 99.9% by weight of the total amount of the liquid flux. If the solvent (d) is less than 20% by weight, the viscosity of the flux becomes high, and the applicability of the flux may be deteriorated. On the other hand, when the solvent (d) exceeds 99.99% by weight, the active component (such as rosin) as a flux is relatively decreased, and the bondability may be lowered.

The rosin or rosin derivative (a) dissolves and removes the oxide from the surfaces of the metal particles (A) and the metal member, makes the metal particles (A) easy to heat-sinter, and the metal particles (A) The adhesion between the heat-sintered material and the metal member is improved. However, since synthetic resins usually do not have such an action, an oxide removal activator is used in combination. Even if rosin or a rosin derivative is insufficient in such action, it is preferably used in combination with the oxide film removal activator (b).

Dioxideamine, triethylamine, propylamine, dipropylamine, tripropylamine, butylamine, dibutylamine, tributylamine, hexylamine, octylamine, monoethanolamine, diethanolamine, triethanolamine, cyclohexyl as the oxide film removal activator (b) Hydrochloric acid salts or bromates of amines such as amine, methylcyclohexylamine, dimethylcyclohexylamine, diphenylguanidine; many types such as succinic acid, malonic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid Monovalent carboxylic acids such as caproic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, behenic acid; citric acid, 1,2-hydroxystearic acid, Hydroxy fatty acids such as 1,2-hydroxyoleic acid; tetrabromomethane, 1,1,2,2-tetrabromobutane, 1,2-dibromo-2-butene, 2,3-diboromo-1-propanol, 1,2 -Organic halides such as diboromo-2,3-butanediol, trans-2,3-diboromo-2-butene-1,4-diol, 2,2-bis (bromomethyl) -1,3-propanediol Is done.

Here, the amine is preferably an aliphatic amine having 2 to 12 carbon atoms, the monovalent carboxylic acid is preferably a monovalent aliphatic carboxylic acid having 6 to 18 carbon atoms, and the polyvalent carboxylic acid is preferably 2 to 2 carbon atoms. 12 polyhydric aliphatic carboxylic acids are preferred, the hydroxy fatty acids are preferably mono- or polyhydric hydroxy fatty acids having 6 to 18 carbon atoms, and the organic halides are halogenated aliphatic hydrocarbons having 1 to 4 carbon atoms. preferable.

The content of the oxide film removal activator (b) is usually 0.01 to 30% by weight, preferably 0.1 to 10% by weight of the total amount of flux, although it depends on the metal oxide removal ability of the substrate. It is. When the oxide film removal activator (b) is less than 0.01% by weight, the activity is insufficient and the bonding property may be deteriorated. On the other hand, if the oxide film removing activator (b) exceeds 30% by weight, the film property of the flux is lowered and the hydrophilicity is increased, so that the corrosiveness and the insulating property may be lowered.

The thixotropic agent (c) imparts or improves thixotropic properties to the paste mixture of the metal particles (A) and the liquid base resin, or the paste mixture of the metal particles (A), the solid base resin and the solvent. There is an effect of improving the application workability and injection workability of the bonding agent for metal members.
Examples of the thixotropic agent (c) include hydrogenated castor oil, fatty acid amide, dibenzylidene sorbitol and the like.

The thixotropic agent (c) is a paste-like mixture of metal particles (A) and a liquid substrate, or a paste-like mixture of metal particles (A), a solid base resin and a solvent has thixotropic properties. Although not necessarily required, the content thereof is usually 1.0 to 25% by weight, preferably 3.0 to 10% by weight, based on the total amount of the liquid flux (B).

The liquid flux (B) may further contain pigments, antioxidants, surfactants, amines, antifungal agents, rust inhibitors, matting agents and the like.
The liquid flux (B) can be easily prepared by mixing required amounts of necessary components with a general-purpose mixer or the like.

These liquid fluxes (B) are excellent in printability with a metal mask, extrudability from a syringe, and dischargeability when mixed with metal particles (A) to form a paste, and have appropriate thixotropic properties. is doing.

The blending amount of the liquid flux (B) may be an amount sufficient to make the metal particles (A) into a paste, and varies depending on the specific gravity, average particle diameter (median diameter D50), shape, etc. of the metal particles (A). However, as a guide, it is 5 to 20 parts by weight per 100 parts by weight of the metal particles (A). The paste form includes a cream form and a slurry form.

As long as it does not contradict the purpose of the present invention, the bonding agent for metal members of the present invention includes nanoparticles having an average particle diameter (median diameter D50) of 0.1 μm or less, such as gold, silver, silver, copper, nickel, and aluminum. Non-metallic particles, metal compounds and metal complexes, stabilizers, colorants, and the like may be contained.

The bonding agent for a metal member of the present invention is a porous sintered product having a melting point equivalent to that of the original metal particles (A) by sintering the metal particles (A) by heating, and a metal It has excellent adhesion to the metal member that was in contact with the bonding agent for the member made.

The atmosphere gas for heating may be any of an inert gas, an oxidizing gas, and a reducing gas, but when the metal particles (A) or the metal member is a base metal system, it is an inert gas or a reducing gas. It is preferable. The inert gas is preferably nitrogen gas. The oxidizing gas is preferably composed of oxygen gas and nitrogen gas. In particular, the oxidizing gas is a mixed gas having an oxygen gas concentration of 0.1 to 40% by volume and a nitrogen gas concentration of 99.9 to 60% by volume. It is preferable that there is air, and air may be used. The reducing gas is preferably composed of hydrogen gas and nitrogen gas, particularly preferably a mixed gas having a hydrogen gas concentration of 1 to 40% by volume and a nitrogen gas concentration of 99 to 60% by volume. Further, it is preferably a forming gas having a hydrogen gas concentration of 5% by volume to 25% by volume and a nitrogen gas of 95% by volume to 75% by volume.

The heating temperature should just be a temperature which can sinter a metal particle (A), and is 70 degreeC or more normally, 150 degreeC or more is preferable and it is more preferable that it is 200 degreeC or more. However, if the temperature exceeds 400 ° C., the residual stress increases when the temperature is returned to room temperature, so it is necessary that the temperature be 400 ° C. or less, preferably 350 ° C. or less, more preferably 300 ° C. or less.

The porous sintered product of the metal particles (A) has a melting point equivalent to that of the metal particles (A), and is excellent in electrical conductivity and heat resistance. If the metal particles (A) are silver, the melting point of the porous sintered product is substantially the same as the melting point of silver. Similarly, if the metal particles (A) are copper, the melting point of the porous sintered product is substantially the same as the melting point of copper. The porous sintered product of metal particles (A) is not formed by melting the whole metal particles (A), but is porous because they are joined at the contact interface between the metal particles (A). It is characterized by being.

On the other hand, solder containing tin as a main component, for example, eutectic solder composed of Sn 60% and Pb 40%, lead-free solder particles, such as Sn-In, Sn-Bi, In-Ag, and In-Bi. Type, Sn-Zn type, Sn-Ag type, Sn-Cu type, Sn-Sb type, Sn-Au type, Sn-Bi-Ag-Cu type, Sn-Ge type, Sn-Bi-Cu type, Sn- Cu-Sb-Ag system, Sn-Ag-Zn system, Sn-Cu-Ag system, Sn-Bi-Sb system, Sn-Bi-Sb-Zn system, Sn-Bi-Cu-Zn system, Sn-Ag- Sb-based, Sn-Ag-Sb-Zn-based, Sn-Ag-Cu-Zn-based, Sn-Zn-Bi-based lead-free solder particles,

More specifically, 48Sn / 52In, 43Sn / 57Bi, 97In / 3Ag, 58Sn / 42In, 95In / 5Bi, 60Sn / 40Bi, 91Sn / 9Zn, 96.5Sn / 3.5Ag, 99.3Sn / 0.7Cu, 95Sn / 5Sb, 20Sn / 80Au, 90Sn / 10Ag, Sn90 / Bi7.5 / Ag2 / Cu0.5, 97Sn / 3Cu, 99Sn / 1Ge, 92Sn / 7.5Bi / 0.5Cu, 97Sn / 2Cu / 0.8Sb / 0.2Ag, 95.5Sn / 3.5Ag / 1Zn, 95.5Sn / 4Cu / 0.5Ag, 52Sn / 45Bi / 3Sb, 51Sn / 45Bi / 3Sb / 1Zn, 85Sn / 10Bi / 5Sb, 84Sn / 10Bi / 5Sb / 1Zn, 88.2Sn / 10Bi / 0.8Cu / 1Zn, 89Sn / 4Ag / 7Sb, 88 n / 4Ag / 7Sb / 1Zn, 98Sn / 1Ag / 1Sb, 97Sn / 1Ag / 1Sb / 1Zn, 91.2Sn / 2Ag / 0.8Cu / 6Zn, 89Sn / 8Zn / 3Bi, 86Sn / 8Zn / 6Bi, 89.1Sn / Since 2Ag / 0.9Cu / 8Zn is obtained by melting and alloying the metal constituting the solder, it is not porous and becomes a uniform solid.

As shown in FIG. 1, the porous sintered product of metal particles (A) has many fine pores and voids, and continuous voids, that is, pores. There are various shapes and sizes of the pores. Since the gaps between the sinterable metal particles before sintering are mainly pores, they are usually 0.1-50 μm, but continuous pores can be much longer than 50 μm. In addition, although there may exist a flux residue in this pore, even in this case, it can be removed by solvent cleaning described later.

The porous sintered product of the metal particles (A) is the proportion of the space in the cross section of the porous sintered product (there may be a flux residue in the space, but this part is the space (the same applies hereinafter) In the present invention, the porosity) is preferably 5 area% or more and 50 area% or less, and more preferably 10 area% or more and 40 area% or less. As a method for measuring the ratio of the space (porosity) in the porous sintered product, a normal method can be used. For example, the cross section of the sintered product is photographed with an electron microscope, the area ratio between the metal part and the space part in the photograph is obtained with image analysis software, the photograph taken with the electron microscope is printed on homogeneous paper, etc. Examples include a method of measuring the weight by dividing the portion and the space portion with scissors and measuring the respective weights, and the like.

The melting point of the porous sintered product of the metal particles (A) is preferably higher than 400 ° C., which is the upper limit value of the heat sintering temperature, and is preferably equivalent to the metal particles (A). The melting point varies depending on the material of the metal particles (A), but is preferably 600 ° C. or higher. If the metal particles (A) are silver, the temperature is preferably 900 ° C. or more, and if copper is copper, the temperature is preferably 1000 ° C. or more.

The electrical conductivity of the porous sintered product of the metal particles (A) is preferably 1 × 10 ⁻² Ω · cm or less in terms of volume resistivity, and more preferably 1 × 10 ⁻⁴ Ω · cm or less. preferable. Moreover, as for the joining strength of the joined body by the porous sintered product of the metal member, the shear adhesive strength is preferably 5 MPa or more, and more preferably 10 MPa or more. These melting points, volume resistivity and shear bond strength are measured by the methods described in the examples.

The bonding agent for a metal member of the present invention, when heated, the metal particles (A) sinter together, is excellent in strength and electrical conductivity, and is a metal member that has been in contact, such as a gold-plated substrate, a gold alloy substrate, silver plating Metal substrate, silver substrate, silver alloy substrate, copper-plated substrate, copper substrate, copper alloy substrate, palladium-plated substrate, metal substrate such as palladium alloy substrate, etc. Adhesive to metal parts such as electrodes on electrically insulating substrate Since it becomes a porous sintered product, it is useful for joining a metal substrate, an electronic component having a metal part, an electronic device, an electrical component, an electrical device, or the like.

Such bonding includes bonding of chip components such as capacitors and resistors and circuit boards; bonding of semiconductor chips such as diodes, memories, and CPUs to lead frames or circuit boards; bonding of high heat generating CPU chips and cooling plates. An electrode forming material on a semiconductor or a substrate is exemplified.

Washing after heating the metal member bonding agent of the present invention to sinter the metal particles (A) is not necessary, but may be washed with pure water or an organic solvent as in the case of solder. Examples of the organic solvent include volatile alcohols, ketones, ethers, and hydrocarbons. The washing method is not limited, and a method of washing by pouring a solvent, a method of washing by immersing in a solvent, and a method of washing by spraying a solvent are exemplified, but a method of washing while applying ultrasonic vibration is preferable. .

Since the bonding agent for metal members of the present invention contains a liquid component, 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 exemplified by 10 ° C. or less, but it is particularly preferable that the temperature is such that the liquid flux (B) does not solidify in the sealed container.
When a syringe is used for the sealed container, a very small amount can be discharged using a dispenser or an ink jet.

The method for producing a metal member assembly of the present invention comprises (A) heat-sinterable metal particles having an average particle diameter (median diameter D50) of greater than 0.1 μm and not greater than 50 μm and a melting point of greater than 400 ° C. A melting point equivalent to metal particles (A) obtained by sintering metal particles (A) by interposing a paste-like material composed of a liquid flux between a plurality of metal members and heating at 70 ° C. to 400 ° C. A plurality of metal members are joined together by a porous sintered product having

(A) Heat-sinterable metal particles having an average particle diameter (median diameter D50) greater than 0.1 μm and not more than 50 μm and a melting point higher than 400 ° C., (B) liquid flux, paste-like material comprising these, metal member , Atmosphere gas when heating, heating at 70 ° C. to 400 ° C., sintering of metal particles (A), melting point of porous sintered product, proportion of space occupied in porous sintered product ( The porosity is as described above. Here, the shear bond strength and the volume resistivity are measured by the methods described in the examples.

In the metal member assembly of the present invention, the plurality of metal members have a porosity of 5 to 50 area%, a melting point higher than 400 ° C., and a volume resistivity of 1 × 10 ⁻² Ω · cm or less. It is characterized by being joined by a porous sintered product.
The melting point, porosity, flux, and volume resistivity of the metal member and porous sintered product are as described above.
The metal member assembly has a shear bond strength at 250 ° C. of preferably 5 MPa or more, and more preferably 10 MPa or more. Here, the melting point, shear bond strength and volume resistivity are measured by the methods described in the examples.

(A) Heat-sinterable metal particles having an average particle diameter (median diameter D50) greater than 0.1 μm and less than 50 μm and a melting point higher than 400 ° C. A paste-like material made of flux is useful for manufacturing an electric circuit connecting electrode.

The method for producing an electric circuit connecting bump of the present invention comprises: (A) heat-sinterable metal particles having an average particle diameter (median diameter D50) of greater than 0.1 μm and not greater than 50 μm and a melting point of greater than 400 ° C .; A paste-like material composed of a liquid flux is applied in a dot shape to an electric circuit connecting pad on a semiconductor element or an electric circuit connecting electrode on a substrate, and heated at 70 ° C. or higher and 400 ° C. or lower, The metal particles are sintered to form metal bumps on the semiconductor element or the substrate.

Examples of the method for applying the paste-like material in the form of dots include dripping, dispensing, printing (for example, screen printing), metal mask application, and inkjet application.
(A) A paste-like product composed of heat-sinterable metal particles having an average particle diameter (median diameter D50) greater than 0.1 μm and not more than 50 μm and a melting point higher than 400 ° C. and (B) a liquid flux, The atmospheric gas, heating at 70 ° C. to 400 ° C., and sintering of the metal particles (A) are as described above.
The metal bump is a porous sintered product of metal particles (A), and its melting point is higher than 400 ° C., preferably 600 ° C. or higher. Ratio) is usually 5 area% or more and 50 area% or less, preferably 10 area% or more and 40 area% or less.

The electrical circuit connection electrodes on the semiconductor element and the substrate thus formed have high strength and extremely high electrical conductivity due to the sintering of the metal particles (A), so that the electrical circuit and the substrate of the semiconductor element It can be used to form the upper electric circuit connection electrode. Examples of the semiconductor element include a diode, a transistor, a memory, and a CPU. The electric circuit and the electrode are usually made of gold, silver, copper, palladium, an alloy of each metal, or plating of each metal.

Examples and comparative examples of the present invention will be given. In the examples and comparative examples, “parts” means “parts by weight”. The proportion of the space in the porous sintered product of the metal particles (A) (void ratio), melting point, volume resistivity, and shear bond strength of the joined body at 250 ° C. were measured by the following methods. Measurements were made at 23 ° C. except for the melting point and the shear bond strength of the joined body at 250 ° C. The boiling point is a value at normal pressure.

[Porosity of porous sintered product]
A 1 mm thick stainless steel mask having a 15 mm square opening was placed on the polyimide resin plate, and a metal member bonding agent was applied by printing. This was put in a gas flow furnace at room temperature, the atmospheric gas was replaced with the predetermined gas described in the examples, and the predetermined gas was flowed at a flow rate of 1 liter / min. The temperature was raised and held at 280 ° C. for 1 hour, and then cooled to room temperature to sinter the metal particles in the metal member bonding agent. This metal particle sintered product was removed from the polyimide resin plate to obtain a test piece for measuring porosity.
A cross section of the plate-like specimen thus obtained was photographed with an electron microscope, and the porosity was calculated using image analysis software (NIH Image manufactured by National Institute of Health, USA), and expressed in area%.

[Melting point of metal particle (A) or porous sintered product]
A porous sintered product prepared for measuring the porosity was scraped off with a nipper to prepare a test piece for melting point measurement. The metal particle (A) or a test piece for measuring the melting point is heated to 1200 ° C. in a nitrogen gas atmosphere at a heating rate of 10 ° C./min with a differential thermal analyzer (DTG-60AH manufactured by Shimadzu Corporation), and the temperature of the endothermic peak Was the melting point.

[Volume resistivity of porous sintered product]
A 1 mm thick stainless steel mask having a 15 mm square opening was placed on the polyimide resin plate, and a metal member bonding agent was applied by printing. This was put in a gas flow furnace at room temperature, the atmospheric gas was replaced with the predetermined gas described in the examples, and the predetermined gas was flowed at a flow rate of 1 liter / min. The temperature was raised and held at 280 ° C. for 1 hour, and then cooled to room temperature to sinter the metal particles in the metal member bonding agent. The porous sintered product was removed from the polyimide resin plate to obtain a test specimen. The volume resistivity (unit: Ω · cm) of the test piece for volume resistivity measurement thus obtained was measured by a method according to JIS K 7194.

[Shear bond strength of metal member assembly at 250 ° C.]
100 μm-thick metal mask having four openings (2.5 mm × 2.5 mm) at an interval of 10 mm on a silver substrate (purity 99% or more) of width 25 mm × length 70 mm and thickness 1.0 mm Was used to print and apply a bonding agent for a metal member, and a silver chip (purity 99.9% or more) having a size of 2.5 mm × 2.5 mm × 0.5 mm was mounted thereon. The silver substrate on which this silver chip is mounted is placed in a gas flow furnace at room temperature, and the atmospheric gas is replaced with a predetermined gas. The temperature was raised to 0 ° C., kept at 280 ° C. for 1 hour, and then cooled to room temperature. The silver substrate and the silver chip were joined by sintering the metal particles in the metallic member joining agent as described above. The test body for bonding strength measurement thus obtained (see FIG. 2 and FIG. 3) was set on a test body fixture having an adhesive strength tester temperature of 250 ° C., and the side surface of the silver chip was bonded to the test machine. The pressure at a thickness of 23 mm / min was pressed with a pressing rod of No. 1, and the load when the bonded portion was sheared was determined as the shear adhesive strength at 250 ° C. (unit: MPa).

[Reference Example 1]
All are commercially available (a) 15 parts of polymerized rosin (acid number 160, softening point 100 ° C.), (a) 36 parts of acrylic acid-modified rosin (acid number 240, softening point 120 ° C.), (d) terpineol (boiling point 219) ° C) 5 parts, (d) 35 parts of diethylene glycol monohexyl ether (boiling point 259 ° C), (b) 5 parts of trans-2,3-dibromo-2-butene-1,4-diol (melting point 114 ° C) and (c ) 4 parts of hardened castor oil was uniformly mixed with a mixer equipped with a stirring blade to prepare a liquid flux. The viscosity of this liquid flux was 10 Pa · s. The viscosity was measured at 25 ° C. using a rotary viscometer (RB80 type, manufactured by Toki Sangyo Co., Ltd.) using an H2 rotor (the same applies hereinafter).

[Reference Example 2]
All are commercially available (a) 15 parts of polymerized rosin (acid number 160, softening point 100 ° C.), (b) 30 parts of diphenylguanidine hydrobromide (melting point 157 ° C.), (b) 1,2-hydroxyolein A liquid flux was prepared by uniformly mixing 5 parts of acid (melting point: 6 ° C.) and 50 parts of (d) terpineol (boiling point: 219 ° C.) with a mixer equipped with stirring blades. The viscosity of this liquid flux was 6 Pa · s.

[Reference Example 3]
In each case, 55 parts of commercially available (a) polymerized rosin (acid number 160, softening point 100 ° C.), (c) 5 parts of hardened castor oil, and (d) 40 parts of terpineol (boiling point 219 ° C.) are uniformly mixed with a mixer equipped with a stirring blade. To prepare a liquid flux. The viscosity of this liquid flux was 11 Pa · s.

[Reference Example 4]
In each case, commercially available (a) 55 parts of polymerized rosin (acid number 160, softening point 100 ° C.) and (d) 45 parts of terpineol (boiling point 219 ° C.) were uniformly mixed with a mixer equipped with a stirring blade to prepare a liquid flux. . The viscosity of this liquid flux was 5 Pa · s.

[Reference Example 5]
All are commercially available (b) 15 parts of cyclohexylamine hydrobromide (melting point 195 ° C.), (c) 5 parts of hydrogenated castor oil, and (d) 80 parts of dipropylene glycol (boiling point 232 ° C.). Was mixed well to prepare a slurry-like liquid flux. The viscosity of this liquid flux was 3 Pa · s.

[Reference Example 6]
In any case, 20 parts of (b) cyclohexylamine hydrobromide (melting point 195 ° C.) and 80 parts of (d) dipropylene glycol (boiling point 232 ° C.) are mixed well with a mixer equipped with a stirring blade to form a slurry. A liquid flux was prepared. The viscosity of this liquid flux was 1 Pa · s.

[Reference Example 7]
In each case, commercially available (b) 3 parts of palmitic acid (melting point 63 ° C., monovalent aliphatic carboxylic acid) and (d) 97 parts of dipropylene glycol are mixed well with a mixer equipped with a stirring blade to form a slurry-like liquid flux. Prepared. The viscosity of this liquid flux was 0.2 Pa · s.

[Reference Example 8]
In both cases, 0.5 parts of commercially available (b) glutaric acid (melting point: 97 ° C., divalent aliphatic carboxylic acid) and (d) 99.5 parts of dipropylene glycol (boiling point: 232 ° C.) were mixed with a mixer equipped with a stirring blade. Mix well and prepare a slurry-like liquid flux. The viscosity of this liquid flux was 0.1 Pa · s.

[Example 1]
The average particle diameter (median diameter D50) of primary particles obtained by a laser diffraction method manufactured by a commercially available atomizing method is 1.5 μm, and surface-treated spherical silver particles (silver purity of 99% by weight or more) 100 parts and 10 parts of the liquid flux prepared in Reference Example 1 were uniformly mixed using a spatula to prepare a paste-like metal member bonding agent. This metal member bonding agent was free from sagging and flow when applied with a metal mask, and could be applied in a good shape.

A porous sintered product obtained by heating and sintering under the above conditions in the oxidizing gas, air (oxygen gas concentration 20.9% by volume, the same applies hereinafter). , The melting point of the silver particles and the porous sintered body of silver particles, the volume resistivity of the porous sintered body of silver particles, and the shear bond strength of the joined body were measured.

The above results are summarized in Table 1. From the above results, this metallic member bonding agent is sufficiently sintered to be a porous sintered product having a high melting point that does not melt even at a normal reflow temperature, and has a high electrical conductivity and is a metallic member. It can be seen that it is useful for firmly bonding the electrodes and is useful for forming an electrode having excellent adhesion to the substrate and electrical conductivity.

[Example 2]
Instead of the silver particles produced by the atomization method used in Example 1, the average particle diameter of primary particles obtained by the laser diffraction method produced by the reduction method according to the example of JP-A-54-121270 Example 1 except that granular silver particles (silver purity 99 wt% or more, stearic acid adhesion amount 0.3 wt%) having a (median diameter D50) of 0.8 μm and a surface treated with stearic acid were used. In the same manner, a paste-like bonding agent for metal members was prepared. This metal member bonding agent was free from sagging and flow when applied with a metal mask, and could be applied in a good shape.

A porous sintered product obtained by heating and sintering under the above conditions in the oxidizing gas, air (oxygen gas concentration 20.9% by volume, the same applies hereinafter). , The melting point of the silver particles and the porous sintered body of silver particles, the volume resistivity of the porous sintered body of silver particles, and the shear bond strength of the joined body were measured.

The above results are summarized in Table 1. From the above results, this metallic member bonding agent is sufficiently sintered to be a porous sintered product having a high melting point that does not melt even at a normal reflow temperature, and has a high electrical conductivity and is a metallic member. It can be seen that it is useful for firmly bonding the electrodes and is useful for forming an electrode having excellent adhesion to the substrate and electrical conductivity.

[Example 3]
Instead of the silver particles produced by the atomization method used in Example 1, the average particle size (median diameter D50) of the primary particles produced by the laser diffraction method produced by a commercially available atomization method is 1.5 μm. In the same manner as in Example 1, except that spherical copper particles (copper purity 99% by weight or more) having no surface treatment were used, a paste-like metal member bonding agent was prepared. This metal member bonding agent was free from sagging and flow when applied with a metal mask, and could be applied in a good shape.

About this metallic member bonding agent, when the hydrogen gas concentration which is a reducing gas is 20 volumes and the reducing gas which is a mixed gas of which the nitrogen gas concentration is 80 volume%, when heated and sintered under each of the above conditions, The porosity of the porous sintered product, the melting point of the copper particles and the porous sintered product of the copper particles, the volume resistivity of the porous sintered product of the copper particles, and the shear bond strength of the joined body were measured.

The above results are summarized in Table 1. From the above results, this metallic member bonding agent is sufficiently sintered to be a porous sintered product having a high melting point that does not melt even at a normal reflow temperature, and has a high electrical conductivity and is a metallic member. It can be seen that it is useful for firmly bonding the electrodes and is useful for forming an electrode having excellent adhesion to the substrate and electrical conductivity.

[Example 4]
In Example 3, the porosity of the porous sintered product when heated and sintered under the above conditions using nitrogen gas (purity 99.99 vol%), which is an inert gas, instead of using the reducing gas The melting point of the copper particles and the porous sintered product of copper particles, the volume resistivity of the porous sintered product of copper particles, and the shear bond strength of the joined body were measured.

The above results are summarized in Table 1. From the above results, this metallic member bonding agent is sufficiently sintered to be a porous sintered product having a high melting point that does not melt even at a normal reflow temperature, and has a high electrical conductivity and is a metallic member. It can be seen that it is useful for firmly bonding the electrodes and is useful for forming an electrode having excellent adhesion to the substrate and electrical conductivity.

[Example 5]
In place of the liquid flux prepared in Reference Example 1 used in Example 1, the liquid flux prepared in Reference Example 2 was used. Prepared. This metal member bonding agent was free from sagging and flow when applied with a metal mask, and could be applied in a good shape.
In the same manner as in Example 1, the porosity of the porous sintered product, the melting point of the silver particles and the porous sintered product of the silver particles, and the porous sintered product of the silver particles when heated and sintered under each of the above conditions The volume resistivity and the shear bond strength of the joined body were measured.

The above results are summarized in Table 1. From the above results, this metallic member bonding agent is sufficiently sintered to be a porous sintered product having a high melting point that does not melt even at a normal reflow temperature, and has a high electrical conductivity and is a metallic member. It can be seen that it is useful for firmly bonding the electrodes and is useful for forming an electrode having excellent adhesion to the substrate and electrical conductivity.

[Example 6]
In place of the liquid flux prepared in Reference Example 1 used in Example 1, the liquid flux prepared in Reference Example 3 was used. Prepared. This metal member bonding agent was free from sagging and flow when applied with a metal mask, and could be applied in a good shape.

In the same manner as in Example 1, the porosity of the porous sintered product, the melting point of the silver particles and the porous sintered product of the silver particles, and the porous sintered product of the silver particles when heated and sintered under the above-mentioned conditions. The volume resistivity and the shear bond strength of the joined body were measured.

The results are summarized in Table 2. From the above results, this metallic member bonding agent is sufficiently sintered to be a porous sintered product having a high melting point that does not melt even at a normal reflow temperature, and has a high electrical conductivity and is a metallic member. It can be seen that it is useful for firmly bonding the electrodes and is useful for forming an electrode having excellent adhesion to the substrate and electrical conductivity.

[Example 7]
In place of the liquid flux prepared in Reference Example 1 used in Example 1, the liquid flux prepared in Reference Example 4 was used. Prepared. This metal member bonding agent was able to be applied although there was some sagging in application with a metal mask.

In the same manner as in Example 1, the porosity of the porous sintered product, the melting point of the silver particles and the porous sintered product of the silver particles, and the porous sintered product of the silver particles when heated and sintered under the above-mentioned conditions. The volume resistivity and the shear bond strength of the joined body were measured.

The results are summarized in Table 2. From the above results, this metallic member bonding agent is sufficiently sintered to be a porous sintered product having a high melting point that does not melt even at a normal reflow temperature, and has a high electrical conductivity and is a metallic member. It can be seen that it is useful for firmly bonding the electrodes and is useful for forming an electrode having excellent adhesion to the substrate and electrical conductivity.

[Example 8]
In place of the liquid flux prepared in Reference Example 1 used in Example 1, the liquid flux prepared in Reference Example 5 was used. Prepared. This metal member bonding agent was able to be applied although there was some sagging in application with a metal mask.

In the same manner as in Example 1, the porosity of the porous sintered product, the melting point of the silver particles and the porous sintered product of the silver particles, and the porous sintered product of the silver particles when heated and sintered under each of the above conditions The volume resistivity and the shear bond strength of the joined body were measured.

The results are summarized in Table 2. From the above results, this metallic member bonding agent is sufficiently sintered to be a porous sintered product having a high melting point that does not melt even at a normal reflow temperature, and has a high electrical conductivity and is a metallic member. It can be seen that it is useful for firmly bonding the electrodes and is useful for forming an electrode having excellent adhesion to the substrate and electrical conductivity.

[Example 9]
In place of the liquid flux prepared in Reference Example 1 used in Example 1, the liquid flux prepared in Reference Example 6 was used. Prepared. This metal member bonding agent was able to be applied although there was a slight flow in application with a metal mask.

In the same manner as in Example 1, the porosity of the porous sintered product, the melting point of the silver particles and the porous sintered product of the silver particles, and the porous sintered product of the silver particles when heated and sintered under the above-mentioned conditions. The volume resistivity and the shear bond strength of the joined body were measured.

The results are summarized in Table 2. From the above results, this metallic member bonding agent is sufficiently sintered to be a porous sintered product having a high melting point that does not melt even at a normal reflow temperature, and has a high electrical conductivity and is a metallic member. It can be seen that it is useful for firmly bonding the electrodes and is useful for forming an electrode having excellent adhesion to the substrate and electrical conductivity.

[Example 10]
The average particle diameter (median diameter D50) of the primary particles obtained by the laser diffraction method produced in the reduction method used in Example 2 is 0.8 μm, and the surface is stearic acid-treated granular silver particles A paste-like metal member obtained by uniformly mixing 100 parts (silver purity 99% by weight or more, stearic acid adhesion amount 0.3% by weight) and 10 parts of the liquid flux prepared in Reference Example 7 using a spatula A bonding agent was prepared. This metal member bonding agent was free from sagging and flow when applied with a metal mask, and could be applied in a good shape.

A porous sintered product obtained by heating and sintering under the above conditions in the oxidizing gas, air (oxygen gas concentration 20.9% by volume, the same applies hereinafter). , The melting point of the silver particles and the porous sintered body of silver particles, the volume resistivity of the porous sintered body of silver particles, and the shear bond strength of the joined body were measured.

The results are summarized in Table 2. From the above results, this metallic member bonding agent is sufficiently sintered to be a porous sintered product having a high melting point that does not melt even at a normal reflow temperature, and has a high electrical conductivity and is a metallic member. It can be seen that it is useful for firmly bonding the electrodes and is useful for forming an electrode having excellent adhesion to the substrate and electrical conductivity.

[Example 11]
A paste-like bonding member for a metal member was prepared in the same manner as in Example 10, except that the flux prepared in Reference Example 8 was used instead of the liquid flux prepared in Reference Example 7 used in Example 10. did. This metal member bonding agent was free from sagging and flow when applied with a metal mask, and could be applied in a good shape.

A porous sintered product obtained by heating and sintering under the above conditions in the oxidizing gas, air (oxygen gas concentration 20.9% by volume, the same applies hereinafter). , The melting point of the silver particles and the porous sintered body of silver particles, the volume resistivity of the porous sintered body of silver particles, and the shear bond strength of the joined body were measured.

The results are summarized in Table 2. From the above results, this metallic member bonding agent is sufficiently sintered to be a porous sintered product having a high melting point that does not melt even at a normal reflow temperature, and has a high electrical conductivity and is a metallic member. It can be seen that it is useful for firmly bonding the electrodes and is useful for forming an electrode having excellent adhesion to the substrate and electrical conductivity.

[Comparative Example 1]
100 parts of solder particles (manufactured by Nihon Solder Co., Ltd.) comprising 96% by weight of tin, 3% by weight of silver and 1% by weight of copper, and having an average particle diameter of 35 μm of primary particles (median diameter D50) obtained by laser diffraction method Then, 11 parts of the liquid flux prepared in Reference Example 1 were uniformly mixed using a spatula to prepare a paste-like metal member bonding agent. This metal member bonding agent was free from sagging and flow when applied with a metal mask, and could be applied in a good shape.

About this metal member bonding agent, the porosity of the porous sintered product, the solder particles, and the sintered particles when heated and sintered under the above-mentioned conditions in nitrogen gas (purity 99.99 vol%), which is an inert gas, The melting point of the solder particle solidified body, the volume resistivity of the solder particle solidified body, and the shear bond strength of the joined body were measured.

The above results are summarized in Table 3. From the above results, this metal member bonding agent melts by heating and becomes a non-porous uniform solder alloy when cooled to room temperature, and can bond metal members with high electrical conductivity. It was found that when heated at a normal reflow temperature of 250 ° C., it melts again and cannot withstand the use temperature at a high temperature.

[Comparative Example 2]
In Example 4, instead of using the liquid flux prepared in Reference Example 1, a volatile organic solvent, terpineol (manufactured by Wako Pure Chemical Industries, Ltd., reagent grade 1, boiling point 214 to 224 ° C.) was used. In the same manner as in Example 4, a paste-like bonding agent for metal members was prepared. This metal member bonding agent was able to be applied although there was a slight sagging and flow during application with a metal mask.

About this metal member bonding agent, the porosity of the porous sintered product, the copper particles, and the copper particles when heated and sintered in nitrogen gas (purity 99.99% by volume) as an inert gas under the above-mentioned conditions The melting point of the porous sintered body of copper particles, the volume resistivity of the porous sintered body of copper particles, and the shear bond strength of the joined body were measured.

The above results are summarized in Table 3.
From the above results, this metallic member bonding agent was apparently sintered but not sufficient, and it was not possible to obtain high electrical conductivity and a strong metallic member bonding.

[Comparative Example 3]
In Example 1, instead of using the liquid flux prepared in Reference Example 1, a volatile organic solvent, terpineol (manufactured by Wako Pure Chemical Industries, Ltd., reagent grade 1, boiling point 214 to 224 ° C.) was used. In the same manner as in Example 1, a paste-like bonding agent for metal members was prepared. This metal member bonding agent was able to be applied although there was a slight sagging and flow during application with a metal mask.

About the bonding agent for metal members, the porosity of the porous sintered product, the melting point of the silver particles and the porous sintered product of the silver particles, The volume resistivity of the porous sintered product and the shear bond strength of the joined body were measured.

The above results are summarized in Table 3.
From the above results, this metallic member bonding agent was apparently sintered but not sufficient, and it was not possible to obtain high electrical conductivity and a strong metallic member bonding.

[Example 12]
A copper wiring circuit (width: 1 mm, length: 50 mm, thickness: 30 μm) formed on a ceramic plate with a thickness of 1.2 mm is gold-plated on both ends of the electric circuit, 1 mm long, 1 mm wide, 100 μm thick. The paste-like silver particle composition used in Example 1 was printed and applied in the form of dots using a metal mask having the following openings. The ceramic plate was heated in a forced circulation oven at 280 ° C. for 1 hour to sinter the silver particles, thereby producing electric circuit connecting bumps.
The electric circuit connecting bumps formed on both ends of the electric circuit were a porous sintered body of silver particles, and were firmly bonded to the gold plating on the surface of the electric circuit. When the electric resistance between the bumps for connecting an electric circuit was measured, it was less than 0.05Ω, and the electric conductivity was practically sufficient.

The bonding agent for metal members of the present invention is used for forming various electronic parts such as resistors and capacitors and electrodes for various display elements; forming an electroconductive film for electromagnetic wave shielding; capacitors, resistors, diodes, memories, computing elements ( It is useful for bonding chip components such as CPU) to a substrate; forming electrodes of solar cells; forming external electrodes of chip-type ceramic electronic components such as multilayer ceramic capacitors, multilayer ceramic inductors, and multilayer ceramic actuators.

The method for producing a metal member assembly of the present invention is useful for producing a metal member assembly having excellent bonding strength and electrical conductivity.
The metal member assembly of the present invention is useful for an electronic component in which the metal member has a metal substrate or a metal portion.

A Specimen 1 for measuring shear strength 1 Silver substrate 2 Sintered product of bonding agent for metal parts 3 Silver chip

Claims (14)

(A) a paste-like product comprising metal particles having an average particle size (median diameter D50) of greater than 0.1 μm and not greater than 50 μm, a melting point of greater than 400 ° C. and heat-sinterable, and (B) a liquid flux; By heating at 70 ° C. or more and 400 ° C. or less, the metal particles (A) are sintered to have a melting point equivalent to that of the metal particles (A) and are in contact with the metal member in the course of sintering A bonding agent for metal members, which is a porous sintered product having adhesiveness. The bonding agent for metal members according to claim 1, wherein the metal particles (A) are produced by an atomizing method and have a metal oxide layer on the surface. The metal particles (A) are silver particles or copper particles, the melting point of the metal particles (A) and the porous sintered product thereof is higher than 600 ° C., and the volume resistivity of the silver particles and the porous sintered product is 1 ×. 10 ^-4 Ω · cm or less, and wherein the volume resistivity of the copper particles and porous sinter is not more than 1 × 10 ^-2 Ω · cm, according to claim 1 or claim 2 Bonding agent for metal parts. The liquid flux (B) is (a) a liquid material composed of rosin or a derivative thereof and (d) a solvent, (a) a liquid material composed of a rosin or a derivative thereof, (b) an oxide film removal activator and (d) a solvent. (A) rosin or derivative thereof, (c) thixotropic agent, and (d) liquid product comprising (d) solvent, (a) rosin or derivative thereof, (b) oxide removal agent and (c) thixotropic agent And (d) a liquid consisting of a solvent, (b) a liquid consisting of an oxide film removal activator and (d) a solvent, or (b) an oxide film removal activator and (c) a thixotropic agent (d The metal member bonding agent according to claim 1, 2 or 3, which is a liquid material comprising a solvent. The metal member bonding agent according to claim 1, 2, or 3, wherein a porosity in a cross section of the porous sintered product is 5 to 50% by area. (A) A plurality of pastes made of metal particles having an average particle size (median diameter D50) of greater than 0.1 μm and less than 50 μm, a melting point of greater than 400 ° C. and heat-sinterable, and (B) a liquid flux. By interposing between metal members and heating at 70 ° C. or more and 400 ° C. or less, the metal particles (A) are sintered together to form a porous sintered product having a melting point equivalent to that of the metal particles (A). A method for producing a metal member assembly, characterized in that the metal members are joined together. The method for producing a metal member assembly according to claim 6, wherein the metal particles (A) are produced by an atomizing method and have a metal oxide layer on the surface. The metal particles (A) are silver particles or copper particles, the metal particles (A) and the melting point thereof are higher than 600 ° C., and the volume resistivity of the silver particles and the porous sintered product thereof is 1 × 10 ⁻⁴ Ω · cm. The metal member assembly according to claim 6 or 7, wherein the volume resistivity of the copper particles and the porous sintered product thereof is 1 × 10 ^-2 Ω · cm or less. Manufacturing method. The liquid flux (B) is (a) a liquid material composed of rosin or a derivative thereof and (d) a solvent, (a) a liquid material composed of a rosin or a derivative thereof, (b) an oxide film removal activator and (d) a solvent. (A) rosin or derivative thereof, (c) thixotropic agent, and (d) liquid product comprising (d) solvent, (a) rosin or derivative thereof, (b) oxide removal agent and (c) thixotropic agent And (d) a liquid consisting of a solvent, (b) a liquid consisting of an oxide film removal activator and (d) a solvent, or (b) an oxide film removal activator and (c) a thixotropic agent (d The method for producing a metal member assembly according to claim 6, 7 or 8, wherein the metal member assembly is a liquid material comprising a solvent. The method for producing a metal member assembly according to claim 6, wherein the porosity in the cross section of the porous sintered product is 5 to 50 area%. The plurality of metal members obtained by the manufacturing method according to claim 6 have a porosity in a cross section of 5 to 50 area%, a melting point higher than 400 ° C., and a volume resistivity of 1 × 10 ⁻² Ω. A metal member joined body characterized by being joined by a porous sintered product of heat-sinterable metal particles (A) having a size of cm or less. The metal particles (A) are silver particles or copper particles, the metal particles (A) and the melting point thereof are higher than 600 ° C., and the volume resistivity of the silver particles and the porous sintered product thereof is 1 × 10 ⁻⁴ Ω · cm. The volume resistivity of the copper particles and the porous sintered product thereof is 1 × 10 ⁻² Ω · cm or less, and the shear bonding strength of the metal member assembly at 250 ° C. is 5 MPa or more. The metal member joined body according to claim 11, wherein The metal member assembly according to claim 11 or 12, wherein the metal member is a metal substrate or an electronic component having a metal portion. The metal member bonding agent according to any one of claims 1 to 4 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, and 70 A method for producing a bump for connecting an electric circuit, wherein the metal particles are sintered by heating at a temperature of at least 400 ° C. and not more than 400 ° C. to form a metal bump on a semiconductor element or substrate.