JP6509770B2 - Conductive metal powder paste - Google Patents

Description

  The present invention relates to a conductive metal powder paste.

  Circuit formation by screen printing has attracted attention in recent years. In screen printing, only the necessary amount of circuit material is printed on the substrate. As a base material, Si wafer, glass, and a resin film are mentioned. As the circuit material, a conductive paste containing a metal filler and a solvent, and optionally a resin is used. The main metal fillers include silver powder, silver-plated copper powder and copper powder. The conductive paste may be of a resin curing type or a baking type depending on its components. Such conductive pastes are increasingly used as conductive adhesives and bonding materials except for wiring applications.

  The resin-curable paste is composed of a resin such as phenol, a curing accelerator such as imidazole, a thickener, if necessary, an adhesive improver with a substrate, and the like in addition to the metal filler and the solvent. The metal filler is in the form of flakes of about 1 to 10 μm. The characteristic of this type of paste is that baking at a temperature of 300 ° C or less and 200 ° C or less depending on the product gives a specific resistance of 100μΩcm or less, so it is difficult to use for wiring applications. Are widely used in chemical applications. Sintering between metal fillers does not occur in the sintered body, and the main factor for developing conductivity is considered to be contact between the fillers. Generally, it is cheaper than the baking type paste described later.

  On the other hand, the fired paste is generally composed of metal nanoparticles as a filler and a solvent. When sintering nanoparticles at low temperatures, the resin is not added to the paste as it becomes a sintering obstacle. The characteristic of the baking type paste is that a specific resistance as low as 20 μΩcm or less, sometimes 5 μΩcm or less can be obtained by baking at 300 ° C. or less and 200 ° C. or less depending on the product. Moreover, since the size of the filler is 100 nm or less, the surface of the sintered body becomes flat. Silver powder paste is known as a baking type paste (patent document 1, patent document 2, patent document 3).

International Publication WO2011 / 155055 JP, 2013-028859, A published patent gazette JP, 2009-120949, published patent publication

  As described above, the resin-curable paste has a high resistivity as a bonding material for wiring applications and heat radiation applications. In addition, since the filler has a size of several μm, the coating does not become flat. This may be an obstacle as a chip bonding material in the power module.

  On the other hand, although the baking type paste can obtain a sufficiently low specific resistance for wiring applications and heat radiation applications, it requires a synthesis reagent and a synthesis time, and is therefore expensive. Moreover, while it is necessary to thicken the bonding layer in heat radiation applications, the baking type paste is poor in thixotropy since a resin is added, and a thick coating film can not be formed.

  Therefore, it is possible to form a thick coating film like a resin-curable paste, and at the same time obtain a low specific resistance at a relatively low temperature like a baking type paste and form a flat coating film. A metal powder paste has been sought.

  Therefore, an object of the present invention is to provide a conductive metal powder paste which can be fired at a low temperature and can achieve low specific resistance while introducing a resin to form a thick coating film.

  As a result of earnest research, the inventors of the present invention performed amine treatment on copper powder or silver powder and used a specific resin for amine-treated copper powder or silver powder while introducing a resin, while low temperature baking was performed. The present invention has been achieved by finding that a conductive metal powder paste can be obtained that can be consolidated and can achieve low specific resistance.

（ただし、式中、ｎは、１〜８の整数であり、
Ｒ基は、以下のいずれかの基である：
−ＮＲ¹Ｒ²基
（ただし、Ｒ¹及びＲ²はそれぞれ独立に、
Ｃ１〜Ｃ８のアルキル基、Ｃ１〜Ｃ８のヒドロキシアルキル基、Ｃ２〜Ｃ８のアルコキシアルキル基、Ｃ７〜Ｃ１０の置換又は無置換のフェニルアルキル基、Ｃ６〜Ｃ８の置換又は無置換のフェニル基、Ｃ１２〜Ｃ１６の置換又は無置換のナフチル基、Ｃ３〜Ｃ８の直鎖又は分枝のアルケニル基からなる群から選択された基である。）
又は
−［Ｎ⁺Ｒ¹Ｒ²Ｒ³］Ｘ₁ ^-基
（ただし、Ｒ¹、Ｒ²及びＲ³はそれぞれ独立に、
Ｃ１〜Ｃ８のアルキル基、Ｃ１〜Ｃ８のヒドロキシアルキル基、Ｃ２〜Ｃ８のアルコキシアルキル基、Ｃ７〜Ｃ１０の置換又は無置換のフェニルアルキル基、Ｃ６〜Ｃ８の置換又は無置換のフェニル基、Ｃ１２〜Ｃ１６の置換又は無置換のナフチル基、Ｃ３〜Ｃ８の直鎖又は分枝のアルケニル基からなる群から選択された基であり、
Ｘ₁ ^-は、ハロゲン化物イオン、ＣＨ₃ＳＯ₄ ^-からなる群から選択された１価のアニオンである））
で表される窒素含有有機物である、（１）に記載の導電性金属粉ペースト。
（３）
Ｔｇ（ガラス転移点）が５０℃〜２００℃の範囲にある樹脂が、ポリビニルアセタール系樹脂、ロジン、アクリル、ポリビニルアルコール、及びポリビニルピロリドンよりなる群から選択された１種以上の樹脂である、（１）〜（２）のいずれかに記載の導電性金属粉ペースト。
（４）
金属粉の比表面積が０．１ｍ²ｇ^-1以上である、（１）〜（３）のいずれかに記載の導電性金属粉ペースト。
（５）
さらに溶媒を含有する、（１）〜（４）のいずれかに記載の導電性金属粉ペースト。
（６）
（１）〜（５）のいずれかに記載の導電性金属粉ペーストを、焼成して、焼成体を得る工程、
を含む、導電性焼成体の製造方法。
（７）
（１）〜（５）のいずれかに記載の導電性金属粉ペーストを、塗工して、塗膜を得る工程、
得られた塗膜を焼成して、焼成体を得る工程、
を含む、導電性焼成体の製造方法。
（８）
焼成の温度が、２２０℃〜３００℃の範囲の温度である、（６）〜（７）のいずれかに記載の方法。 Therefore, the present invention includes the following (1):
(1)
60-90 mass% of copper powder or silver powder which nitrogen-containing organic substance adhered to the surface,
A conductive metal powder paste comprising 0.1 to 10% by mass of a resin having a Tg (glass transition point) in the range of 50 ° C. to 200 ° C.,
The nitrogen-containing organic substance is
An amino acid; or any of the following groups:
-CH (OH) -CH ₂ -NR ¹ R ² group (wherein R ¹ and R ² are each independently
C1-C8 alkyl group, C1-C8 hydroxyalkyl group, C2-C8 alkoxyalkyl group, C7-C10 substituted or unsubstituted phenylalkyl group, C6-C8 substituted or unsubstituted phenyl group, C12- It is a group selected from the group consisting of a C16 substituted or unsubstituted naphthyl group and a C3 to C8 linear or branched alkenyl group. )
Or -CH (OH) -CH _2- [N ⁺ R ¹ R ² R ³ ] X ₁ ^- group (however, R ¹ , R ² and R ³ are each independently
C1-C8 alkyl group, C1-C8 hydroxyalkyl group, C2-C8 alkoxyalkyl group, C7-C10 substituted or unsubstituted phenylalkyl group, C6-C8 substituted or unsubstituted phenyl group, C12- A group selected from the group consisting of a C16 substituted or unsubstituted naphthyl group and a C3 to C8 linear or branched alkenyl group,
X ₁ ^- is a halide ion, CH ₃ SO ₄ ^- is a monovalent anion selected from the group consisting of)
Conductive metal powder paste which is an amine compound having one or more.
(2)
The nitrogen-containing organic compound has the following formula I:

(Wherein, n is an integer of 1 to 8,
The R group is any of the following groups:
An -NR ¹ R ² group (provided that R ¹ and R ² are each independently
C1-C8 alkyl group, C1-C8 hydroxyalkyl group, C2-C8 alkoxyalkyl group, C7-C10 substituted or unsubstituted phenylalkyl group, C6-C8 substituted or unsubstituted phenyl group, C12- It is a group selected from the group consisting of a C16 substituted or unsubstituted naphthyl group and a C3 to C8 linear or branched alkenyl group. )
Or-[N ⁺ R ¹ R ² R ³ ] X ₁ ^- group (with the proviso that R ¹ , R ² and R ³ are each independently
C1-C8 alkyl group, C1-C8 hydroxyalkyl group, C2-C8 alkoxyalkyl group, C7-C10 substituted or unsubstituted phenylalkyl group, C6-C8 substituted or unsubstituted phenyl group, C12- A group selected from the group consisting of a C16 substituted or unsubstituted naphthyl group and a C3 to C8 linear or branched alkenyl group,
X ₁ ^- is a halide ion, CH ₃ SO ₄ ^- is a monovalent anion selected from the group consisting of))
The electroconductive metal-powder paste as described in (1) which is nitrogen-containing organic substance represented by these.
(3)
The resin having a Tg (glass transition temperature) in the range of 50 ° C. to 200 ° C. is one or more resins selected from the group consisting of polyvinyl acetal resins, rosins, acrylics, polyvinyl alcohol, and polyvinyl pyrrolidone 1) Conductive metal powder paste in any one of-2).
(4)
The electroconductive metal-powder paste in any one of (1)-(3) whose specific surface area of metal powder is 0.1 m < ² > g < ^-1 > or more.
(5)
The conductive metal powder paste according to any one of (1) to (4), further containing a solvent.
(6)
A step of firing the conductive metal powder paste according to any one of (1) to (5) to obtain a fired body,
A method for producing a conductive fired body, comprising:
(7)
A step of applying the conductive metal powder paste according to any one of (1) to (5) to obtain a coated film,
Baking the obtained coating film to obtain a fired body,
A method for producing a conductive fired body, comprising:
(8)
The method in any one of (6)-(7) whose temperature of baking is temperature of the range of 220 degreeC-300 degreeC.

  According to the present invention, it is possible to obtain a conductive metal powder paste which can be fired at low temperature and can achieve low specific resistance while introducing a resin to form a thick coating film.

  Hereinafter, the present invention will be described in detail by way of embodiments. The present invention is not limited to the specific embodiments described below.

[Conductive metal powder paste]
The conductive metal powder paste of the present invention contains 60 to 90% by mass of copper powder or silver powder with a nitrogen-containing organic substance attached to the surface, and a resin having a Tg (glass transition point) in the range of 50 ° C to 200 ° C. It contains 0.1 to 10% by mass.

[Nitrogen-containing organic matter]
The above nitrogen-containing organic substance is
An amino acid; or any of the following groups:
-CH (OH) -CH ₂ -NR ¹ R ² group (wherein R ¹ and R ² are each independently
C1-C8 alkyl group, C1-C8 hydroxyalkyl group, C2-C8 alkoxyalkyl group, C7-C10 substituted or unsubstituted phenylalkyl group, C6-C8 substituted or unsubstituted phenyl group, C12- It is a group selected from the group consisting of a C16 substituted or unsubstituted naphthyl group and a C3 to C8 linear or branched alkenyl group. )
Or -CH (OH) -CH _2- [N ⁺ R ¹ R ² R ³ ] X ₁ ^- group (however, R ¹ , R ² and R ³ are each independently
C1-C8 alkyl group, C1-C8 hydroxyalkyl group, C2-C8 alkoxyalkyl group, C7-C10 substituted or unsubstituted phenylalkyl group, C6-C8 substituted or unsubstituted phenyl group, C12- A group selected from the group consisting of a C16 substituted or unsubstituted naphthyl group and a C3 to C8 linear or branched alkenyl group,
X ₁ ^- is a halide ion, CH ₃ SO ₄ ^- is a monovalent anion selected from the group consisting of)
Or an amine compound having one or more.

（ただし、式中、ｎは、１〜８の整数であり、
Ｒ基は、以下のいずれかの基である：
−ＮＲ¹Ｒ²基
（ただし、Ｒ¹及びＲ²はそれぞれ独立に、
Ｃ１〜Ｃ８のアルキル基、Ｃ１〜Ｃ８のヒドロキシアルキル基、Ｃ２〜Ｃ８のアルコキシアルキル基、Ｃ７〜Ｃ１０の置換又は無置換のフェニルアルキル基、Ｃ６〜Ｃ８の置換又は無置換のフェニル基、Ｃ１２〜Ｃ１６の置換又は無置換のナフチル基、Ｃ３〜Ｃ８の直鎖又は分枝のアルケニル基からなる群から選択された基である。）
又は
−［Ｎ⁺Ｒ¹Ｒ²Ｒ³］Ｘ₁ ^-基
（ただし、Ｒ¹、Ｒ²及びＲ³はそれぞれ独立に、
Ｃ１〜Ｃ８のアルキル基、Ｃ１〜Ｃ８のヒドロキシアルキル基、Ｃ２〜Ｃ８のアルコキシアルキル基、Ｃ７〜Ｃ１０の置換又は無置換のフェニルアルキル基、Ｃ６〜Ｃ８の置換又は無置換のフェニル基、Ｃ１２〜Ｃ１６の置換又は無置換のナフチル基、Ｃ３〜Ｃ８の直鎖又は分枝のアルケニル基からなる群から選択された基であり、
Ｘ₁ ^-は、ハロゲン化物イオン、ＣＨ₃ＳＯ₄ ^-からなる群から選択された１価のアニオンである））
で表される窒素含有有機物である。 In a preferred embodiment, the nitrogen-containing organic compound has the following formula I:

(Wherein, n is an integer of 1 to 8,
The R group is any of the following groups:
An -NR ¹ R ² group (provided that R ¹ and R ² are each independently
C1-C8 alkyl group, C1-C8 hydroxyalkyl group, C2-C8 alkoxyalkyl group, C7-C10 substituted or unsubstituted phenylalkyl group, C6-C8 substituted or unsubstituted phenyl group, C12- It is a group selected from the group consisting of a C16 substituted or unsubstituted naphthyl group and a C3 to C8 linear or branched alkenyl group. )
Or-[N ⁺ R ¹ R ² R ³ ] X ₁ ^- group (with the proviso that R ¹ , R ² and R ³ are each independently
C1-C8 alkyl group, C1-C8 hydroxyalkyl group, C2-C8 alkoxyalkyl group, C7-C10 substituted or unsubstituted phenylalkyl group, C6-C8 substituted or unsubstituted phenyl group, C12- A group selected from the group consisting of a C16 substituted or unsubstituted naphthyl group and a C3 to C8 linear or branched alkenyl group,
X ₁ ^- is a halide ion, CH ₃ SO ₄ ^- is a monovalent anion selected from the group consisting of))
It is a nitrogen-containing organic substance represented by

In a preferred embodiment, these substituents (R ¹ , R ² , R ³ ) are selected such that the amine compound as a whole has water solubility.

  The alkyl group can be, for example, C1 to C8 (having 1 to 8 carbon atoms), C1 to C6, C1 to C3 and C1 to C2. The hydroxyalkyl group can be, for example, C1-C8, C1-C6, C1-C3, C1-C2. The alkoxyalkyl group can be, for example, C1 to C8, C1 to C6, C1 to C3, or C1 to C2, and can be, for example, a methoxyalkyl group, an ethoxyalkyl group, or a propoxyalkyl group. The phenylalkyl group can be, for example, C7 to C10 and C7 to C8, and the phenyl group of the phenylalkyl group may be a substituted or unsubstituted phenyl group, for example, the phenyl group of the phenylalkyl group is a C1 to C3 alkyl It may be substituted one or two by a group. The phenyl group may be, for example, C6 to C8 or C6 to C7, and may be a substituted or unsubstituted phenyl group, and may be substituted, for example, one or two by a C1 to C3 alkyl group. The naphthyl group may be, for example, C12 to C16 and C12 to C14, and may be a substituted or unsubstituted naphthyl group, and may be substituted, for example, by one or two C1 to C3 alkyl groups. The alkenyl group can be, for example, C3 to C8, C3 to C6, or C3 to C4, and may have a linear or branched skeleton.

[Attachment of nitrogen-containing organic matter to the surface]
An aqueous solution of a nitrogen-containing organic matter, such as the above-mentioned amine compound, can be mixed with copper powder or silver powder and deposited on the surface of copper powder or silver powder. The mass of the nitrogen-containing organic substance attached is, for example, in the range of 0.03 mass% to 70 mass% and 2 mass% to 60 mass% with respect to the total mass of the copper powder or silver powder to which the nitrogen-containing organic substance is attached can do. Optionally, after mixing copper powder or silver powder with an aqueous solution of an amine compound, the residue is separated from the solution by a known means, dried and disintegrated if necessary, and thereafter producing a conductive metal powder paste. It may be in a form suitable for

[Analysis of amine attached to the surface of copper powder or silver powder]
The nitrogen-containing organic substance attached to the surface of the copper powder or silver powder can be the above-mentioned amine compound. The method of determining the amine on the surface of the surface-treated copper powder or silver powder is, for example, ultra high performance liquid chromatography time-of-flight mass spectrometry (UPLC / TOF-MS), whereby the molecular weight and molecular structure of the amine are identified. Because it can be direct qualitative and semi-quantitative. On the other hand, even with liquid chromatography, qualitative and semi-quantitative determination is possible indirectly.

[resin]
As a resin having a Tg (glass transition point) in the range of 50 ° C. to 200 ° C., for example, at least one resin selected from the group consisting of polyvinyl acetal resin, rosin, acrylic, polyvinyl alcohol, and polyvinyl pyrrolidone is used it can. Examples of polyvinyl acetal resins include polyvinyl butyral (also referred to as butyral resin). Acrylic (acrylic resin) includes polymers of acrylic acid esters or polymers of methacrylic acid esters, and examples thereof include poly (methyl methacrylate). Rosin is a natural resin containing as a main component rosin acid (abietic acid, parastoric acid, isopimaric acid, etc.).

[Metal powder]
As metal powder, the copper powder or silver powder manufactured by the well-known method is used. In a preferred embodiment, for example, copper powder or silver powder produced by a wet method, copper powder or silver powder produced by a dry method can be used. Preferably, copper powder produced by a wet method, for example, copper powder produced by a disproportionation method, a chemical reduction method or the like can be used.

[Specific surface area of metal powder]
The specific surface area of the metal powder can be, for example, 0.1 m ² g ⁻¹ or more, 0.5 m ² g ⁻¹ or more, and for example, 15 m ² g ⁻¹ or less, 10 m ² g ⁻¹ or less .

[solvent]
In a preferred embodiment, the conductive metal powder paste further contains a copper powder or silver powder having a nitrogen-containing organic substance attached to the surface, and a solvent, in addition to the resin. The content of the solvent can be, for example, the mass% of the remainder of the sum of the content of the copper powder or silver powder with the nitrogen-containing organic substance adhering to the surface and the content of the resin. When other additives are added to the conductive metal powder paste, the content can be made to be the remaining mass% of the sum of the content of the copper powder or the silver powder and the content of the resin.

  As the solvent, a known solvent which becomes a solvent of the resin to be used, and which volatilizes at a temperature within the range of the above Tg or lower can be used. For example, a solvent having a boiling point in the range of 100 to 300 ° C. and in the range of 120 to 250 ° C. can be used. In a preferred embodiment, terpineol, butyl carbitol, butyl carbitol acetate, polyethylene glycol, propylene glycol, ethyl carbitol, butyl cellosolve acetate, butyl cellosolve, diacetone alcohol, binene, cyclohexanone, turpentine oil, propylene glycol monomethyl ether as a solvent A solvent selected from the group consisting of acetate, xylene, ethyl cellosolve and propylene glycol monomethyl ether can be used, preferably terpineol and butyl carbitol.

[Coating]
The conductive metal powder paste of the present invention, which contains a resin, is excellent in thixotropy and can form a sufficiently thick coating film. The coating film can be formed by applying a conductive metal powder paste. Examples of the coating method include screen printing, inkjet printing, inkjet printing, metal mask printing, microcontact method, pad printing and the like. In a preferred embodiment, the thickness of the coating can be, for example, in the range of 10 to 500 μm and in the range of 20 to 200 μm. The coating can be dried as appropriate, if desired, and then fired. In a preferred embodiment, the thickness of the coating after drying can be, for example, in the range of 20 to 500 μm.

[Firing]
The coating film of the conductive metal powder paste can be fired at a low temperature, and a fired body with low specific resistance can be obtained. The firing temperature can be a temperature higher than the above Tg range, for example, can be in the range of 220 ° C. to 300 ° C.

Bonding strength
The conductive metal powder paste can bond the members with sufficiently high bonding strength by firing the coating. Therefore, combined with the ability to achieve low specific resistance, it can be suitably used, for example, as a bonding material for chips in power modules. In a preferred embodiment, the bonding strength can be, for example, 0 MPa or more and 1 MPa or more, and can be, for example, in the range of 0 MPa to 5 MPa, and in the range of 0 MPa to 3 MPa.

[Resistance]
The fired body of the conductive metal powder paste has a sufficiently low specific resistance. In a preferred embodiment, the specific resistance can be, for example, in the range of 1.7 to 100 μΩcm, in the range of 5 to 50 μΩcm. Such low specific resistance is in the range which could not be achieved when the conventional conductive metal powder paste contained a resin.

[atmosphere]
The firing can be performed, for example, in a non-oxidizing atmosphere or a reducing atmosphere. The non-oxidizing atmosphere means an atmosphere containing no or reduced oxidizing gas, such as an atmosphere in which oxygen is completely or sufficiently removed. The reducing atmosphere contains a reducing gas such as CO, H ₂ S, SO ₂ , H ₂ , HCHO, HCOOH, H ₂ O, etc. at 0.5 vol% or more, preferably 1.0 vol% or more. I say the atmosphere. As a reducing atmosphere, for example, an atmosphere containing gaseous nitrogen and gaseous hydrogen at atmospheric pressure can be mentioned.

[Sintered body]
The present invention also relates to the above-mentioned conductive metal powder paste, and to a coating film and a dried coating film formed by coating the conductive metal powder paste, and also to a fired body formed by baking the coating film, There is also a way. This sintered body has a low specific resistance, is an excellent electrode, and is an excellent bonding material. The present invention also resides in these electrodes, a bonding material, and a method of manufacturing the same.

  The present invention will be described in more detail by way of the following examples. The present invention is not limited to the following examples.

(Example 1: Synthesis of amine (A1 to A6))
The amine compounds (A1 to A6) were synthesized as nitrogen-containing organic substances (organic substances) according to the following procedure.
A three-necked flask was charged with 10.0 g of an epoxy compound (Denacol EX-521 (manufactured by Nakase ChemteX Co., Ltd.)) and 5.72 g of diethanolamine, and a cooling pipe using dry ice-methanol as a cooling medium was prepared. The reaction was carried out for 3 hours to obtain a diethanolamine-modified compound. The structure of the obtained diethanolamine compound is as follows.

  Similarly, compounds modified with bis (2-ethoxyethyl) amine, dibenzylamine, diphenylamine, diallylamine, and dimethylamine, respectively, were obtained. The structure of the product was identified by FT-IR, 1 H-NMR and 13 C-NMR. Hereinafter, the diethanolamine compound, the dimethylamine compound, the bis (2-ethoxyethyl) amine compound, the dibenzylamine compound, the diphenylamine compound, and the diallylamine compound are respectively represented as A1 to A6.

(Example 2: Synthesis of amine (B1 to B6))
The amine compounds (B1 to B6) were synthesized as nitrogen-containing organic substances (organic substances) by the following procedure.
A three-necked flask was charged with 10.0 g of an epoxy compound (Denacol EX-521 (manufactured by Nakase ChemteX Co., Ltd.)) and 5.72 g of diethanolamine, and a cooling pipe using dry ice-methanol as a cooling medium was prepared. The reaction was allowed to proceed for 3 hours. Thereafter, the cooling pipe was removed, and nitrogen gas was blown into the reaction solution to remove excess diethanolamine. Finally, 6.88 g of benzyl chloride was added to the reaction solution, and the reaction was performed at 100 ° C. for 3 hours. The structure of the product was identified by FT-IR, 1 H-NMR and 13 C-NMR. The structure of the obtained diethanolamine compound is as follows.

  Similarly, compounds modified with bis (2-ethoxyethyl) amine, dibenzylamine, diphenylamine, diallylamine, and dimethylamine, respectively, were obtained. The structure of the product was identified by FT-IR, 1 H-NMR and 13 C-NMR. Hereinafter, the diethanolamine compound, the dimethylamine compound, the bis (2-ethoxyethyl) amine compound, the dibenzylamine compound, the diphenylamine compound, and the diallylamine compound are respectively described as B1 to B6.

  The structures of the synthesized compounds A1 to A6 and B1 to B6 are structural formulas in which n = 3 in the following formula I, and R groups are substituted as shown in the following table 1, respectively.

Formula I:

(Example 3: Examples 1 to 3, 5 to 21, Comparative Example 2)
In a 1 L beaker, 50 g of copper suboxide powder and 0.25 g of animal glue purified from gum arabic or fish as a protective agent (grain growth inhibitor) are dispersed in 350 mL of pure water and diluted there with 25% volume ratio 100 mL of sulfuric acid was added to carry out disproportionation reaction. Decantation and water washing were repeated from this slurry to obtain 20 g of copper fine particles having a specific surface area of 3.5 m ² / g (D50 0.2 μm). After mixing 20 g of this copper fine particle and 100 mL of an aqueous solution containing a predetermined amount of various amines as an organic substance (nitrogen-containing organic substance) at 300 rpm for 1 hour, copper fine powder was recovered. Then, after drying at 70 ° C. in nitrogen for 1 hour, it was crushed to obtain surface-treated copper fine particles. A predetermined amount of each resin was added to the copper fine particles, and terpineol was added as a solvent in a predetermined amount, and the remainder was mixed with a mixer as a solvent, and then the paste was adjusted with a triple roll. As resin, acrylic resin (SOKEN CHEMICAL SPB-K113), rosin (Wako Pure Chemical Industries, Ltd.), butyral (Sekisui Chemical S-LEC SV-02), polyvinyl alcohol (Sekisui Chemical SELVOL), polyvinyl pyrrolidone (Nippon Catalyst K-85) And cellulose (Wako Pure Chemical Industries ethylcellulose) were used. These pastes were screen-printed on a copper plate by screen printing to a dry film thickness of about 50 μm and a dry film thickness of about 10 μm. A copper plate of 3 mm square was placed on this dried coating, and pressed and fired in 2% H ₂ -N ₂ at 250 ° C. for 5 minutes at 1 MPa (bonding condition 1). A lateral force was applied to a 3 mm square copper plate of the obtained bonded sample to measure the bonding strength.

(Example 4: Example 4)
The paste of Example 1 is screen-printed on a copper plate, a 3-mm square copper plate is placed on the coating without drying the coating, and 60% at 250 ° C. in 2% H ₂ -N _2. It pressure-fired (joining condition 2). A lateral force was applied to a 3 mm square copper plate of the obtained bonded sample to measure the bonding strength.

(Example 5: Example 22)
Alkaline copper foil powder AFS-Cu (specific surface area: 0.4 m ² / g) manufactured by Nippon Atomizing Co., Ltd. is alkali-washed, pickled and washed with water, then amine-treated in the procedure of Example 3 to carry out surface-treated copper fine particles, The paste was produced and the bonding strength was measured.

(Example 6: Example 23)
Milled according to JP-A-2007-291513. That is, 12.6 g of silver nitrate was dissolved in 0.8 L of pure water, 24 mL of 25% aqueous ammonia and 40 g of ammonium nitrate were further added to prepare a silver ammine complex salt aqueous solution. To this, gelatin was added at a ratio of 0.5 g / L, and this was used as an electrolyte, and both the anode and the cathode were electrodeposited at a current density of 200 A / m ² and a solution temperature of 20 ° C using a DSE electrode plate. The silver particles were electrolyzed for 1 hour while being scraped off from the station number. The silver powder thus obtained was filtered with a Nutche, washed in order of pure water and alcohol, and dried at 70 ° C. for 12 hours in the air. The silver powder was subjected to dry classification to finally obtain a silver powder having a specific surface area of 2.3 m ² / g (D50 0.4 μm). The silver powder was subjected to amine treatment according to the procedure of Example 3 to prepare surface-treated copper fine particles and a paste thereof, and the bonding strength was measured.

(Example 7: Example 24)
Alkali washing, pickling and washing with silver flake powder AgC-GS (specific surface area: 0.4 m ² / g) manufactured by Fukuda Metal Foil & Powder Industry Co., Ltd., followed by amine treatment by the procedure of Example 3 for surface treatment Copper fine particles and a paste thereof were produced, and the bonding strength was measured.

(Example 8: Comparative Example 1)
50 g of cuprous oxide powder and 0.25 g of gum arabic as a protective agent (grain growth inhibitor) are dispersed in 350 mL of pure water in a 1 L beaker, and 100 mL of dilute sulfuric acid having a volume ratio of 25% is added thereto to disproportionate The reaction was done. Decantation and water washing were repeated from this slurry, and 20 g of copper microparticles having a specific surface area of 3.5 m ² / g (D50 0.2 μm) were recovered. The copper particles were mixed with 350 mL of a sodium hydroxide aqueous solution having a liquid temperature of 25 ° C. and pH 9.0 for 10 minutes, and the copper particles were separated by decantation. The mixture was mixed with 100 mL of an aqueous solution containing this copper particulate and 0.2 g of BTA for 30 minutes, and the copper particulate was recovered by suction filtration. Copper fine particles crushed in the procedure of Example 3 were processed into a paste and the bonding strength was measured.

(Example 9: Examples 1 and 4)
In the procedure of Example 3, Kapton tape was applied to the bonding surface of a 3 mm square copper plate. The pastes of Examples 1 and 4 were coated on the copper plate according to the procedures of Examples 3 and 4, respectively, and a copper plate of 3 mm square was placed on the copper plate with the surface on which the Kapton tape was attached as a bonding surface, and fired under each condition. . After firing, the 3 mm square copper plate was removed, and the specific resistance of the obtained fired body was measured.

(Summary of results)
The results of the above-described experiments performed on Examples 1 to 24 and Comparative Examples 1 and 2 are summarized in Table 2.

  The present invention provides a conductive metal powder paste that can be fired at low temperature and achieve low specific resistance while introducing a resin to form a thick coating film. The present invention is an industrially useful invention.

Claims (7)

60 to 90% by mass of copper powder or silver powder with nitrogen-containing organic matter attached to the surface,
A conductive metal powder paste containing 0.1 to 10% by mass of a resin having a Tg (glass transition point) in the range of 50 ° C. to 200 ° C.,
The nitrogen-containing organic substance is
An amino acid; or any of the following groups:
-CH (OH) -CH ₂ -NR ¹ R ² group (wherein R ¹ and R ² are each independently
C1-C8 alkyl group, C1-C8 hydroxyalkyl group, C2-C8 alkoxyalkyl group, C7-C10 substituted or unsubstituted phenylalkyl group, C6-C8 substituted or unsubstituted phenyl group, C12- It is a group selected from the group consisting of a C16 substituted or unsubstituted naphthyl group and a C3 to C8 linear or branched alkenyl group. )
Or -CH (OH) -CH _2- [N ⁺ R ¹ R ² R ³ ] X ₁ ^- group (however, R ¹ , R ² and R ³ are each independently
C1-C8 alkyl group, C1-C8 hydroxyalkyl group, C2-C8 alkoxyalkyl group, C7-C10 substituted or unsubstituted phenylalkyl group, C6-C8 substituted or unsubstituted phenyl group, C12- A group selected from the group consisting of a C16 substituted or unsubstituted naphthyl group and a C3 to C8 linear or branched alkenyl group,
X ₁ ^- is a halide ion, CH ₃ SO ₄ ^- is a monovalent anion selected from the group consisting of)
Conductive metal powder paste which is an amine compound having one or more of
The resin having a Tg (glass transition point) in the range of 50 ° C. to 200 ° C. is at least one resin selected from the group consisting of polyvinyl acetal resins, rosins, acrylics, polyvinyl alcohols, and polyvinyl pyrrolidones. Metal powder paste . 60 to 90% by mass of copper powder or silver powder with nitrogen-containing organic matter attached to the surface,
A conductive metal powder paste containing 0.1 to 10% by mass of a resin having a Tg (glass transition point) in the range of 50 ° C. to 200 ° C.,
The nitrogen-containing organic substance is
Amino acid; or
One of the following groups:
^{_{-CH (OH) -CH 2 -NR 1}} R 2 groups
(However, R ¹ and R ² are each independently
C1-C8 alkyl group, C1-C8 hydroxyalkyl group, C2-C8 alkoxyalkyl group, C7-C10 substituted or unsubstituted phenylalkyl group, C6-C8 substituted or unsubstituted phenyl group, C12- It is a group selected from the group consisting of a C16 substituted or unsubstituted naphthyl group and a C3 to C8 linear or branched alkenyl group. )
Or
_{-CH (OH) -CH 2 - [} N + R 1 R 2 R 3] X 1 - group
(However, R ¹ , R ² and R ³ are each independently
C1-C8 alkyl group, C1-C8 hydroxyalkyl group, C2-C8 alkoxyalkyl group, C7-C10 substituted or unsubstituted phenylalkyl group, C6-C8 substituted or unsubstituted phenyl group, C12- A group selected from the group consisting of a C16 substituted or unsubstituted naphthyl group and a C3 to C8 linear or branched alkenyl group,
X ₁ ^- is a halide ion, CH ₃ SO ₄ ^- is a monovalent anion selected from the group consisting of)
Conductive metal powder paste which is an amine compound having one or more of
The nitrogen-containing organic compound has the following formula I:

(Wherein, n is an integer of 1 to 8,
The R group is any of the following groups:
-NR ¹ R ² group
(However, R ¹ and R ² are each independently
C1-C8 alkyl group, C1-C8 hydroxyalkyl group, C2-C8 alkoxyalkyl group, C7-C10 substituted or unsubstituted phenylalkyl group, C6-C8 substituted or unsubstituted phenyl group, C12- It is a group selected from the group consisting of a C16 substituted or unsubstituted naphthyl group and a C3 to C8 linear or branched alkenyl group. )
Or
-[N ⁺ R ¹ R ² R ³ ] X ₁ ^- group
(However, R ¹ , R ² and R ³ are each independently
C1-C8 alkyl group, C1-C8 hydroxyalkyl group, C2-C8 alkoxyalkyl group, C7-C10 substituted or unsubstituted phenylalkyl group, C6-C8 substituted or unsubstituted phenyl group, C12- A group selected from the group consisting of a C16 substituted or unsubstituted naphthyl group and a C3 to C8 linear or branched alkenyl group,
X ₁ ^- is a halide ion, CH ₃ SO ₄ ^- is a monovalent anion selected from the group consisting of))
Conductive metal powder paste which is a nitrogen-containing organic substance represented by The specific surface area of the metal powder is 0.1 m ² g ^-1 or more, the conductive metal powder paste as claimed in any one of claims 1-2. The conductive metal powder paste according to any one of claims 1 to 3 , further comprising a solvent. A step of firing the conductive metal powder paste according to any one of claims 1 to 4 to obtain a fired body,
A method for producing a conductive fired body, comprising: A step of applying the conductive metal powder paste according to any one of claims 1 to 4 to obtain a coated film,
Baking the obtained coating film to obtain a fired body,
A method for producing a conductive fired body, comprising: The method according to any one of claims 5 to 6 , wherein the firing temperature is a temperature in the range of 220 ° C to 300 ° C.