TWI527069B - And a method for producing metal powder paste - Google Patents

Description

Metal powder paste and manufacturing method thereof

The present invention relates to a metal powder paste suitable for the manufacture of electrodes for wafer-stacked ceramic capacitors and a method of manufacturing the same.

Wafer-layered ceramic capacitors are electronic components that can be used in a variety of electronic devices because of their small size and large capacity. The wafer-layered ceramic capacitor has a structure in which a ceramic dielectric body and an internal electrode are laminated in a layered manner, and each layer of the laminated layer constitutes a capacitor element, and the elements are electrically connected in parallel by an external electrode, thereby integrally Become a small and large capacity capacitor.

In the manufacture of a wafer-stacked ceramic capacitor, a sheet of a dielectric body is produced in the following manner. That is, first, an organic binder and a solvent as a dispersing agent or a molding aid are added to a dielectric raw material powder such as BaTiO ₃ , and a slurry is obtained by a pulverization, mixing, and defoaming step. Thereafter, the slurry is applied to a carrier film such as a PET (polyethylene terephthalate) film by a coating method such as a die coating method to form a thin coating. It is dried to obtain a thin dielectric sheet (green sheet).

On the other hand, the metal powder which is a raw material of the internal electrode of the wafer-stacked ceramic capacitor is mixed with the organic binder and the solvent as a dispersing agent or a molding aid, and the defoaming step is carried out in the same manner as in the case of the dielectric raw material powder. It becomes a slurry copper paste (copper paste). For the copper paste paste, the internal electrode is printed on the green sheet (dielectric sheet) by screen printing, and dried. After drying, the green sheet after the printing is peeled off from the carrier film, and a plurality of such green sheets are laminated.

After the laminated green sheets are applied with a pressing pressure of 10 to 100 MPa and integrated, they are cut into individual wafers. Thereafter, the internal electrode layer and the dielectric layer are sintered by a calciner at a high temperature of about 1000 °C. A wafer laminated ceramic capacitor was fabricated in this manner.

Regarding the internal electrodes of the above-mentioned wafer-stacked ceramic capacitor, Pt was used at the time of development of the technology, but Pd and Pd-Ag alloys were used from the viewpoint of cost, and Ni was mainly used at present. However, in recent years, from the viewpoint of environmental regulation, it has been gradually required to replace Ni with Cu. Moreover, if Ni is replaced by Cu, in principle, low inductance can be achieved in high frequency applications. Moreover, Cu also has the advantage of being lower in cost than Ni.

On the other hand, with the miniaturization of capacitors, the internal electrodes tend to be thinner, and the next generation type is said to be about 1 μm. Therefore, it is expected that the particle size of the powder for internal electrodes used for the copper paste is smaller.

In addition, the melting point of the original Cu is lower than that of Pt, Pd, and Ni. Further, the surface area is increased by the reduction in the diameter of the particles as expected, and the increase in the surface area causes the melting point to decrease. Thus, when Cu is used as the internal electrode powder, the Cu powder is melted at a lower temperature during calcination. It will start. It induces cracks in the electrode layer itself. Further, since the electrode layer is rapidly contracted after the temperature is lowered, there is a possibility of causing peeling (delamination) of the dielectric layer and the electrode layer. In order to avoid the above-mentioned problem, the metal powder for internal electrodes is required to have the same heat shrinkage characteristics as those of the dielectric material, and as an index indicating the sintering start temperature.

In response to the above requirements, a method of surface-treating the Cu powder used for the copper paste has been proposed in order to obtain a copper powder paste suitable for the internal electrode of the wafer-stacked ceramic capacitor.

Patent Document 1 (Japanese Patent No. 4001438) is a technique in which a Cu powder is dispersed in a solution, an aqueous solution of a water-soluble salt of a metal element is added thereto, and a pH value is adjusted to fix the metal oxide on the surface of the Cu powder, and further Causing the surface treated copper powders to collide with each other Strengthen the fixation of the surface treatment layer. However, since the step is composed of adsorption of metal oxide onto copper powder and fixation strengthening, there is a problem in productivity. Further, when the particle diameter of the copper powder is smaller than 0.5 μm, since the size is close to the metal oxide particles to be adsorbed, it is expected that the adsorption of the oxide onto the copper powder itself becomes difficult.

Patent Document 2 (Japanese Patent No. 4164009) is a technique of coating copper powder with a polyoxygenated oil having a specific functional group. However, since the oil is mixed with the Cu powder, it is easy to aggregate, and there is a problem in workability. Moreover, the filtration at the time of separation of the oil and the Cu powder is difficult, and there is a problem in workability.

Patent Document 3 (Japanese Patent No. 3646259) is a technique in which a hydrolyzed alkoxysilane is condensed and polymerized on the surface of a copper powder by an ammonia catalyst to form a SiO ₂ gel coat film. However, when applied to copper powder having a particle diameter of 1 μm or less, it is necessary to continuously add NH ₃ as a catalyst to prevent aggregation, but the reaction control is extremely difficult depending on the specific operational skill of the addition, and thus workability And there are problems in terms of productivity.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 4001438

[Patent Document 2] Japanese Patent No. 4164009

[Patent Document 3] Japanese Patent No. 3646259

As described above, a copper powder paste which is preferably used for the production of internal electrodes of a wafer-laminated ceramic capacitor and which is excellent in sintering retardation, workability, and productivity is required.

Accordingly, it is an object of the present invention to provide a wafer multilayer ceramic capacitor that can be preferably used. A surface-treated copper paste prepared by using an electrode and having excellent sintering retardation and a method for producing the same.

As a result of intensive studies, the inventors have found that by mixing copper powder with an aqueous solution of amino decane, the amino decane is adsorbed on the surface of the copper powder, and does not aggregate after surface treatment, thereby obtaining a sintering delay dramatically. The copper paste is lifted to achieve the present invention. Further, the copper powder paste is obtained by blending a fatty acid when the surface-treated copper powder is dispersed in a solvent, but the aggregation of the surface-treated copper powder is extremely lowered by the blending of the fatty acid. These manufacturing operations are very simple, and do not require superior skills, so that workability is excellent and productivity is excellent. Further, the thus obtained copper powder paste formed of the surface-treated copper powder exhibits a higher sintering initiation temperature although it is a copper powder paste using copper powder having a small particle size. Further, it is understood that even when the metal powder other than the copper powder is subjected to the surface treatment in the same manner, even when the surface treatment is performed by a coupling agent other than the amine decane, the surface having excellent properties can be obtained in the same manner. The metal powder is treated, whereby a metal powder paste having excellent properties can be obtained.

Therefore, the present invention resides in the following (1) to (36).

(1) A copper powder paste which is dispersed in a solvent and comprises: a surface-treated copper powder, wherein the adhesion amount of Si is 500 to 16000 μg with respect to 1 g of copper powder, and the weight % of N relative to copper powder is 0.05. More than %; and organic matter having a carboxyl group.

(2) The copper powder paste of (1), wherein the solvent is dispersed and comprises: a surface-treated copper powder, wherein the adhesion amount of Si is 500 to 16000 μg with respect to 1 g of the copper powder, and the weight of N relative to the copper powder % is 0.05% or more; and an organic substance having a carboxyl group.

(3) A copper powder paste according to (1) or (2), which comprises, in addition to the surface-treated copper powder and an organic substance having a carboxyl group, a binder resin dispersed in a solvent.

(4) The copper powder paste according to any one of (1) to (3), wherein the surface-treated copper powder is a Copper powder surface treated with a decane coupling agent.

(5) A copper powder paste according to (4), wherein the decane coupling agent is an amino decane.

(6) The copper powder paste according to any one of (1) to (5), wherein, in the surface-treated copper powder, the weight % of N relative to the copper powder is in the range of 0.05% to 0.50%.

(7) The copper powder paste according to any one of (1) to (6), wherein the surface-treated copper powder is a copper powder obtained by subjecting the surface-treated copper powder to heat treatment to remove N.

(8) The copper powder paste according to any one of (1) to (7) wherein the surface-treated copper powder is subjected to heat treatment in an oxygen atmosphere or an inert atmosphere to remove N copper powder.

(9) The copper powder paste according to any one of (1) to (8), wherein a sintering initiation temperature is 400 ° C or higher.

(10) The copper powder paste according to any one of (1) to (9), wherein the surface-treated copper powder is obtained by mixing an aqueous solution of aminopyridane with copper powder, stirring, and drying and solidifying.

(11) The copper powder paste according to any one of (1) to (10), wherein the surface-treated copper powder is 0.01 mL or more of the amount of the amino decane to be surface-treated with respect to 1 g of the copper powder. Surface treated copper powder under conditions.

(12) The copper powder paste according to (11), wherein the surface-treated copper powder is subjected to surface treatment under the condition that the amount of the amino decane is 0.05 mL or more, mixed with the copper powder, and the stirring time is 30 minutes or less. Copper powder.

(13) A copper powder paste according to any one of (4) to (11), wherein the amino decane is monoamine decane or diamino decane.

(14) The copper powder paste according to any one of (1) to (13), wherein the surface-treated copper powder is a copper powder obtained by surface-treating a raw material copper powder obtained by a wet method.

(15) The copper powder paste according to any one of (1) to (14), wherein the surface-treated copper powder is D50 ≦ 1.5 μm.

(16) The copper powder paste according to any one of (1) to (14) wherein the surface-treated copper powder is D50 ≦ 1.0 μm.

(17) The copper powder paste according to any one of (1) to (14) wherein the surface-treated copper powder is D50 ≦ 0.5 μm, Dmax ≦ 1.0 μm.

(18) The copper powder paste according to any one of (1) to (17), wherein the surface-treated copper powder has a particle size distribution of a peak.

(19) The copper powder paste according to any one of (1) to (18), wherein the copper powder paste is a copper powder paste for internal electrodes.

(20) The copper powder paste according to any one of (1) to (18), wherein the copper powder paste is a copper powder paste for an external electrode.

(21) The copper powder paste according to any one of (1) to (20) wherein the organic substance having a carboxyl group is a carboxylic acid or an amino acid.

(22) The copper powder paste according to any one of (1) to (20) wherein the organic substance having a carboxyl group is a fatty acid.

(23) A copper powder paste according to (22), wherein the fatty acid is a saturated or unsaturated fatty acid of C3 to C24.

(24) A copper powder paste according to (22), wherein the fatty acid is a fatty acid having a C2 to C24 double bond number of 0 to 2.

(25) A copper powder paste according to (22), wherein the fatty acid is selected from the group consisting of crotonic acid, acrylic acid, methacrylic acid, octanoic acid, citric acid, citric acid, lauric acid, myristic acid, pentadecanoic acid, palmitic acid, palm Oleic acid, margaric acid, stearic acid, oleic acid, vaccenic acid, linoleic acid, (9,12,15)-linolenic acid, (6,9,12) - linolenic acid, dihomo-gamma-linolenic acid, tungstic acid, tuberculous stearic acid, arachidic acid (icoic acid), 8,11-eicosadienoic acid, 5,8 , 11-eicosatrienoic acid, arachidonic acid, behenic acid, lignoceric acid, tetracosic acid, oleic acid, sinapic acid, twenty-two carbon One or more of the group consisting of hexaenoic acid, eicosapentaenoic acid, and stearidonic acid.

(26) The copper powder paste according to (22), wherein the fatty acid is one or more selected from the group consisting of stearic acid, oleic acid, and linoleic acid.

(27) The copper powder paste according to any one of (1) to (26) wherein the solvent is an alcohol solvent, a glycol ether solvent, an acetate solvent, a ketone solvent or a hydrocarbon solvent.

(28) A copper powder paste according to (27), wherein the alcohol solvent is selected from the group consisting of terpineol, dihydroterpineol, isopropanol, butyl carbitol, terpine ethoxyethanol, and dihydrofurfuryl One or more of the group consisting of oxyethanol.

(29) The copper powder paste of (27), wherein the glycol ether solvent is one or more selected from the group consisting of butyl carbitol.

(30) A copper powder paste according to (27), wherein the acetate solvent is selected from the group consisting of butyl carbitol acetate, dihydroterpineol acetate, terpineol acetate, dihydrogen glucosinolate One or more of the group consisting of dihydrocarvyl acetate and carotenoid acetate.

(31) A copper powder paste according to (27), wherein the ketone solvent is methyl ethyl ketone.

(32) The copper powder paste of (27), wherein the hydrocarbon solvent is one or more selected from the group consisting of toluene and cyclohexane.

(33) The copper powder paste according to any one of (1) to (32) wherein the mass ratio of the fatty acid to the surface-treated copper powder (fatty acid/surface-treated copper powder) is 1/1000 to 1/1 Within the scope of 10.

The copper powder paste according to any one of (1) to (33), wherein the mass ratio of the fatty acid to the solvent (fatty acid/solvent) is in the range of 1/100 to 1/10.

(35) A copper powder paste according to any one of (1) to (34), wherein a mass ratio of the solvent to the surface-treated copper powder (solvent/surface-treated copper powder) is 1/4 to 1/1 Within the scope of 1.

(36) The copper powder paste according to any one of (1) to (35), wherein a filter having a pore diameter of 5 μm and an effective area of 9.0 cm ² is subjected to a vacuum filtration of 0.3 atm, the quality of the permeation is relative to The percentage (transmittance) of the ratio of the input mass of 4 g was 35% or more after 30 seconds.

Further, the present invention resides in the following (41) to (44).

(41) A wafer-layered ceramic capacitor produced by using the paste of any one of the above (1) to (36).

(42) A multilayer substrate to which a wafer laminated ceramic capacitor of (41) is mounted on the outermost layer.

(43) A multilayer substrate in which a wafer laminated ceramic capacitor of (41) is mounted on an inner layer.

(44) An electronic component in which the multilayer substrate of (42) or (43) is mounted.

Further, the present invention resides in the following (51) to (59).

(51) A method for producing a copper powder paste, comprising the steps of: dissolving a surface-treated copper powder and an organic substance having a carboxyl group in a solvent to prepare a paste, wherein the amount of Si adhered to the surface-treated copper powder is relative to the copper powder 1 g is 500 to 16000 μg, and the weight % of N relative to the copper powder is 0.05% or more.

(52) The method according to (51), wherein the step of preparing the paste is a step of preparing a paste by dissolving the surface-treated copper powder and the organic substance having a carboxyl group, and the amount of Si attached to the surface-treated copper powder is relative to The copper powder 1 g is 500 to 16000 μg, and the weight % of N relative to the copper powder is 0.05% or more.

(53) The method of (51), wherein the step of preparing the paste is a step of preparing a paste by dispersing the binder resin in a solvent in addition to the surface-treated copper powder and the organic substance having a carboxyl group.

(54) The method according to any one of (51) to (53) wherein the organic substance having a carboxyl group is a fatty acid.

(55) The method of any one of (51) to (54), wherein after the step of preparing the paste, the step of filtering the prepared paste with a filter is included.

(56) The method of (55), wherein the filter has a pore diameter of 1 to 8 μm.

(57) The method of (55) or (56), wherein the filtration is carried out by vacuum filtration or pressure filtration The step of filtering with a filter.

(58) The method according to (57), wherein the pressure under reduced pressure filtration is a pressure in the range of 0.1 to 1.0 atm.

(59) The method according to (57), wherein the pressure of the pressure filtration is a pressure in the range of 0.1 to 2.0 atm.

Further, the present invention resides in the following (61) to (79).

(61) The method according to any one of (51) to (59) wherein the surface-treated copper powder is obtained by a method of producing a surface-treated copper powder comprising the steps of: copper powder and an amine A step of preparing a copper powder dispersion by mixing an aqueous solution of decane.

(62) The method of (61), which comprises the step of stirring the copper powder dispersion.

(63) The method of (61) or (62), which comprises the step of ultrasonically treating the copper powder dispersion.

(64) The method of (63), wherein the step of performing the ultrasonic processing is a step of performing ultrasonic processing for 1 to 180 minutes.

(65) The method of any one of (61) to (64), comprising the steps of: filtering a copper powder dispersion to recover copper powder; and drying the filtered copper powder to obtain a surface treatment The step of copper powder.

(66) The method according to (65), wherein the drying is carried out by heat treatment at 50 to 90 ° C for 30 to 120 minutes.

(67) The method of (65) or (66), wherein the drying is carried out in an oxygen atmosphere or an inert atmosphere.

The method according to any one of (61) to (67), wherein the copper dispersion contains 0.025 g or more of amino decane relative to 1 g of the copper powder.

(69) The method according to any one of (61) to (68), wherein the aqueous solution of the amino decane is an aqueous solution of the amino decane represented by the following formula I: H ₂ NR ¹ -Si(OR ² ) ₂ (R ³ ) (Formula I) (wherein, in the above formula I, R1 is linear or branched, saturated or unsaturated, substituted or unsubstituted, cyclic or acyclic, heterocyclic or non-heterocyclic A divalent group of a hydrocarbon of C1 to C12, R2 is an alkyl group of C1 to C5, and R3 is an alkyl group of C1 to C5 or an alkoxy group of C1 to C5.

(70) The method according to (69), wherein R1 is a branched or saturated C1 to C12 selected from a divalent group of a substituted or unsubstituted C1 to C12 linear saturated hydrocarbon; a divalent group of a hydrocarbon, a substituted or unsubstituted C1 to C12 linear unsaturated hydrocarbon, a substituted or unsubstituted C1 to C12 branched unsaturated hydrocarbon, a divalent group, a divalent group of a substituted or unsubstituted C1 to C12 cyclic hydrocarbon, a substituted or unsubstituted C1 to C12 heterocyclic hydrocarbon, a divalent group, a substituted or unsubstituted C1 to C12 aromatic a group in a group consisting of a divalent group of a hydrocarbon.

(71) The method of (69), wherein R1 is selected from the group consisting of -(CH ₂ ) _n -, -(CH ₂ ) _n -(CH) _m -(CH ₂ ) _j-1 -, -(CH ₂ ) _n -(CC)-(CH ₂ ) _n-1 -, -(CH ₂ ) _n -NH-(CH ₂ ) _m -, -(CH ₂ ) _n -NH-(CH ₂ ) _m -NH-(CH _{2 j} -, -(CH ₂ ) _n-1 -(CH)NH ₂ -(CH ₂ ) _m-1 -, -(CH ₂ ) _n-1 -(CH)NH ₂ -(CH ₂ ) _m-1 a group in the group consisting of -NH-(CH ₂ ) _j - (wherein n, m, and j are integers of 1 or more).

(72) The method of (69), wherein R1 is -(CH ₂ ) _n -, or -(CH ₂ ) _n -NH-(CH ₂ ) _m -.

(73) The method of any one of (71) to (72), wherein n, m, j are independently 1, 2 or 3, respectively.

The method of any one of (69) to (73), wherein R2 is methyl or ethyl.

The method of any one of (69) to (74), wherein R3 is methyl, ethyl, methoxy or ethoxy.

The method of any one of (61) to (75), wherein the copper powder is copper powder produced by a wet method.

(77) The method according to any one of (61) to (76), wherein, in the surface-treated copper powder, the adhesion amount of Si is 500 to 16000 μg with respect to 1 g of the copper powder, and the weight of N relative to the copper powder The % is 0.05% or more, and the sintering initiation temperature is 400 ° C or more.

(78) A method of producing an electrode, comprising the steps of: applying a copper powder paste obtained by the production method according to any one of (51) to (57), (61) to (77) to a substrate And a step of heating and calcining the conductive copper paste coated on the substrate.

(79) The method of (78), wherein the electrode is an electrode for a wafer-stacked ceramic capacitor.

Further, the present invention resides in the following (81) to (83).

(81) A copper powder paste produced by the production method according to any one of (51) to (57), (61) to (77).

(82) An electrode produced by the production method of (78).

(83) An electrode for a wafer laminated ceramic capacitor produced by the method of (79).

Further, the present invention resides in the following (91) to (92).

(91) A copper powder paste produced by the method of any one of (51) to (57), (61) to (77), having a pore diameter of 5 μm and an effective area of 9.0 cm ² When the filter was subjected to vacuum filtration at 0.3 atm, the percentage of the ratio of the mass of the permeated mass to the input mass of 4 g (transmittance) was 35% or more after 15 minutes.

(92) An electrode produced by the production method of (78) or (79).

Further, the present invention resides in the following (101) to (155).

(101) A metal powder paste comprising: a surface-treated metal powder in which a solvent is dispersed, wherein an adhesion amount of any one of Si, Ti, Al, Zr, Ce, and Sn is 1 g with respect to the metal powder 200 to 16000 μg, the weight % of N relative to the metal powder is 0.02% or more; and an organic substance having a carboxyl group.

(102) A metal powder paste according to (101), which comprises, in addition to the surface-treated metal powder and an organic substance having a carboxyl group, a binder resin dispersed in a solvent.

(103) The metal powder paste of any one of (101) to (102), wherein the metal powder is copper powder.

The metal powder paste of any one of (101) to (102), wherein the metal powder is any one of Pt, Pd, Ag, Ni, and Cu.

(105) The metal powder paste according to any one of (101) to (104), wherein the adhesion amount of any one of Si, Ti, Al, Zr, Ce, and Sn is 300 to 16,000 with respect to 1 g of the metal powder. Gg.

(10) The metal powder paste according to any one of (101) to (104), wherein the adhesion amount of any one of Si, Ti, Al, Zr, Ce, and Sn is 500 to 16,000 with respect to 1 g of the metal powder. Gg.

The metal powder paste of any one of (101) to (106), wherein the adhesion amount of any one or more of Si, Ti, Al, Zr, Ce, and Sn is 3000 μg or less with respect to 1 g of the metal powder. .

(10) The metal powder paste according to any one of (101) to (106), wherein an adhesion amount of any one or more of Si, Ti, Al, Zr, Ce, and Sn is 1500 μg or less with respect to 1 g of the metal powder. .

The metal powder paste according to any one of (101) to (108), wherein a weight % of N with respect to the metal powder is 0.05% or more.

The metal powder paste according to any one of (101) to (109), wherein any one of Si, Ti, Al, Zr, Ce, and Sn is any one of Ti, Al, Zr, Ce, and Sn. More than one.

The metal powder paste of any one of (101) to (109), wherein any one or more of Si, Ti, Al, Zr, Ce, and Sn is Si.

(112) The metal powder paste of (101), wherein the metal powder is copper powder, the adhesion amount of Si is 500 to 16000 μg with respect to 1 g of copper, and the weight % of N with respect to copper powder is 0.05% or more.

(113) The metal powder paste of (101), wherein the metal powder is copper powder, the adhesion amount of Si is 500 to 3000 μg with respect to 1 g of copper, and the weight % of N with respect to copper powder is 0.05% or more.

The metal powder paste of any one of (101) to (113), wherein the surface-treated metal powder is a metal powder surface-treated with a coupling agent.

(115) The metal powder paste according to any one of (101) to (114), wherein any one or more of Si, Ti, Al, Zr, Ce, and Sn is adsorbed by a coupling agent treatment.

The metal powder paste of any one of (101) to (115), wherein the coupling agent is any one of decane, titanate, and aluminate.

(117) A metal powder paste according to any one of (101) to (116) wherein the coupling agent is a coupling agent having an amine group at the end.

The metal powder paste of any one of (101) to (117), wherein the coupling agent is an amino decane.

(119) The metal powder paste according to any one of (101) to (118) wherein the organic substance having a carboxyl group is a carboxylic acid or an amino acid.

(120) The metal powder paste of any one of (101) to (119), wherein the organic substance having a carboxyl group is a fatty acid.

(121) A metal powder paste according to (120), wherein the fatty acid is a saturated or unsaturated fatty acid of C3 to C24.

(122) The metal powder paste of (120), wherein the fatty acid is a fatty acid having a C2 to C24 double bond number of 0 to 2.

(122) A metal powder paste according to (120), wherein the fatty acid is selected from the group consisting of crotonic acid, acrylic acid, methacrylic acid, octanoic acid, citric acid, citric acid, lauric acid, myristic acid, pentadecanoic acid, palmitic acid, palm Oleic acid, pearlic acid, stearic acid, oleic acid, isooleic acid, linoleic acid, (9,12,15)-linolenic acid, (6,9,12)-linolenic acid, two high - γ-time linoleic acid, tung acid, tuberculous stearic acid, arachidic acid (icoic acid), 8,11-icosadienoic acid, 5,8,11-eicosatrienoic acid, peanut four Oleic acid, behenic acid, tetracosic acid, tetracosic acid, oleic acid, sinapic acid, docosahexaenoic acid, eicosapentaenoic acid, stearidonic acid One or more of the group.

(123) A metal powder paste according to any one of (101) to (122), wherein the solvent is an alcohol solvent, a glycol ether solvent, an acetate solvent, a ketone solvent or a hydrocarbon solvent.

(124) The metal powder paste according to any one of (119) to (123), wherein the mass ratio of the fatty acid to the surface-treated metal powder (fatty acid/surface-treated metal powder) is 1/100 to 1/ Within the scope of 10.

(125) The metal powder paste according to any one of (119) to (124) wherein the mass ratio of the fatty acid to the solvent (fatty acid/solvent) is in the range of 1/100 to 1/10.

(126) The metal powder paste according to any one of (101) to (125), wherein the filter having a pore diameter of 5 μm and an effective area of 9.0 cm ² is subjected to a vacuum reduction of 0.3 atm, the quality of the permeation is relative to The percentage (transmittance) of the ratio of the input mass of 4 g was 35% or more after 30 seconds.

(127) A wafer-layered ceramic capacitor produced by using the paste of any one of (101) to (126).

(128) The wafer-stacked ceramic capacitor of (127), wherein any one of SiO ₂ , TiO ₂ , and Al ₂ O ₃ having a diameter of 10 nm or more is present in the internal electrode cross section.

(129) The wafer-stacked ceramic capacitor of (127) or (128), wherein SiO ₂ , TiO ₂ , and Al ₂ O ₃ having a maximum diameter of 0.5 μm or more exist in a cross section of the internal electrode of 0.5/cm ² or less One.

(130) A method for producing a metal powder paste, comprising the steps of: dissolving a surface-treated metal powder and an organic substance having a carboxyl group in a solvent, wherein the surface-treated metal powder has Si, Ti, Al, Zr, The adhesion amount of any one or more of Ce and Sn is 200 to 16000 μg with respect to 1 g of the metal powder, and the weight % of N with respect to the metal powder is 0.02% or more.

(131) The method of (130), wherein the step of preparing the paste is a step of preparing a paste by dispersing the binder resin in a solvent in addition to the surface-treated metal powder and the organic substance having a carboxyl group.

(132) The method of any one of (130) to (131), wherein the organic substance having a carboxyl group For fatty acids.

The method of any one of (130) to (132), wherein after the step of preparing a paste by dispersing the surface-treated metal powder and the fatty acid in a solvent, the step of filtering the prepared paste by a filter is included.

(134) The method of (133), wherein the filter has a pore size of 1 to 8 μm.

(135) The method of (133) or (134), wherein the step of filtering by a filter is performed by vacuum filtration or pressure filtration.

The method of any one of (130) to (135), wherein the surface-treated metal powder is produced by a method of producing a surface-treated metal powder comprising the steps of: The step of preparing a metal powder dispersion by mixing an aqueous solution of an amine-based coupling agent.

(137) The method according to (136), wherein the metal powder is any one of Pt, Pd, Ag, Ni, and Cu.

(138) The method of (136), wherein the metal powder is copper powder.

(139) The method of (136), wherein the metal powder is any one of Pt, Pd, Ag, and Ni.

(140) The method of any one of (136) to (139), comprising the step of stirring the metal powder dispersion.

(141) The method of any one of (136) to (140) comprising the step of ultrasonically treating the metal powder dispersion.

(142) The method of (141), wherein the step of performing the ultrasonic processing is the step of performing the ultrasonic processing for 1 to 180 minutes.

The method of any one of (136) to (142), comprising the steps of: filtering the metal powder dispersion to recover the metal powder; and drying the filtered metal powder to obtain the surface-treated metal powder.

(144) The method according to (143), wherein the drying is carried out in an oxygen atmosphere or an inert atmosphere.

The method of any one of (136) to (144), wherein the metal dispersion contains 0.025 g or more of an amine group-containing coupling agent with respect to 1 g of the metal powder.

(146) The method according to any one of (136) to (145) wherein the aqueous solution of the aminodecane is an aqueous solution of the amino decane represented by the following formula I: H ₂ NR ¹ -Si(OR ² ) ₂ (R ³ ) (Formula I) (wherein, in the above formula I, R1 is linear or branched, saturated or unsaturated, substituted or unsubstituted, cyclic or acyclic, heterocyclic or non-heterocyclic a divalent group of a hydrocarbon of C1 to C12, R2 is an alkyl group of C1 to C5, and R3 is an alkyl group of C1 to C5 or an alkoxy group of C1 to C5.

(147) The method of (146), wherein R1 is selected from the group consisting of -(CH ₂ ) _n -, -(CH ₂ ) _n -(CH) _m -(CH ₂ ) _j-1 -, -(CH ₂ ) _n -(CC)-(CH ₂ ) _n-1 -, -(CH ₂ ) _n -NH-(CH ₂ ) _m -, -(CH ₂ ) _n -NH-(CH ₂ ) _m -NH-(CH _{2 j} -, -(CH ₂ ) _n-1 -(CH)NH ₂ -(CH ₂ ) _m-1 -, -(CH ₂ ) _n-1 -(CH)NH ₂ -(CH ₂ ) _m-1 a group in the group consisting of -NH-(CH ₂ ) _j - (wherein n, m, and j are integers of 1 or more).

The method of any one of (136) to (145), wherein the aqueous solution of the coupling agent is an aqueous solution of an amine group-containing titanate represented by the following formula II: (H ₂ NR ¹ -O) _p Ti (OR ² ) _q (Formula II) (wherein, in the above formula II, R1 is linear or branched, saturated or unsaturated, substituted or unsubstituted, cyclic or acyclic, having a heterocyclic ring or not a divalent group of a hydrocarbon having a heterocyclic ring of C1 to C12, R2 is a linear or branched C1 to C5 alkyl group, p and q are integers of 1 to 3, and p+q=4).

(149) The method of (148), wherein R1 is selected from the group consisting of -(CH ₂ ) _n -, -(CH ₂ ) _n -(CH) _m -(CH ₂ ) _j-1 -, -(CH ₂ ) _n -(CC)-(CH ₂ ) _n-1 -, -(CH ₂ ) _n -NH-(CH ₂ ) _m -, -(CH ₂ ) _n -NH-(CH ₂ ) _m -NH-(CH _{2 j} -, -(CH ₂ ) _n-1 -(CH)NH ₂ -(CH ₂ ) _m-1 -, -(CH ₂ ) _n-1 -(CH)NH ₂ -(CH ₂ ) _m-1 a group in the group consisting of -NH-(CH ₂ ) _j - (wherein n, m, and j are integers of 1 or more).

The method of any one of (130) to (149), wherein the metal powder is manufactured by a wet method.

The method of any one of (130) to (149), wherein the surface-treated metal powder is as follows: the adhesion amount of any one of Si, Ti, Al, Zr, Ce, and Sn is relative to The metal powder 1 g is 200 to 16000 μg, and the weight % of N with respect to the metal powder is 0.02% or more; and the sintering initiation temperature is 400 ° C or more.

(152) A method of producing an electrode, comprising the steps of: applying a metal powder paste obtained by the production method of any one of (130) to (151) to a substrate; and coating The step of heating and calcining the conductive metal paste on the substrate.

(153) The method of (152), wherein the electrode is an electrode for a wafer-layered ceramic capacitor.

(154) A metal powder paste which is produced by the production method of any one of (130) to (151), and which is 0.3 atm in a filter having a pore diameter of 5 μm and an effective area of 9.0 cm ² . In the filtration under reduced pressure, the percentage (transmittance) of the ratio of the mass of the permeated mass to the input mass of 4 g was 35% or more after 15 minutes.

(155) An electrode produced by the method of (152) or (153), and having SiO ₂ , TiO ₂ , Al having a maximum diameter of 0.5 μm or more in an electrode cross section of 0.5/cm ² or less Any of ₂ O ₃ .

The surface treated copper powder used in the copper powder paste of the present invention is surface treated After that, it does not aggregate, and the sintering delay is excellent, and even if it is a copper powder having a small particle size, it exhibits a high sintering initiation temperature. Therefore, the copper powder paste of the present invention is excellent in sintering retardation and excellent in dispersibility of copper powder in the paste. Therefore, it is possible to avoid the problem of production such as electrode peeling, and it is advantageous to manufacture the electrode for a wafer laminated ceramic capacitor. Further, the surface-treated copper powder can be produced by subjecting the copper powder to be a raw material to a very simple treatment, and the copper powder paste of the present invention can be produced by subjecting the surface-treated copper powder to a very simple treatment. Therefore, it is not necessary to have superior skills, and thus workability and productivity are excellent. Moreover, according to the present invention, even a metal powder other than copper powder can be similarly obtained as a metal powder paste having excellent characteristics.

Figure 1 is a TEM image of a cross section of a surface treated copper powder perpendicular to the surface.

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

In the present invention, a step of preparing a copper powder dispersion by mixing copper powder with an aqueous solution of an amino decane, from which a surface-treated copper powder is obtained, and then the obtained in this manner is carried out. The surface-treated copper powder and the organic substance having a carboxyl group are dispersed in a solvent to prepare a paste, whereby a copper paste can be produced.

In a preferred embodiment, in addition to the surface-treated copper powder and the organic substance having a carboxyl group, the solvent may further disperse the binder resin, and other additives may be added as needed.

In detail, the surface-treated copper powder can be obtained as follows. In the range of the present invention, the copper powder of the raw material is subjected to surface treatment as a starting point of copper powder which is a raw material for surface treatment, and then dispersed in a solvent together with an organic substance having a carboxyl group. And get the copper paste. Further, within the scope of the present invention, there is also included a case where a copper powder paste is obtained starting from the production of the raw material copper powder for surface treatment.

In the present invention, as the organic substance having a carboxyl group, an amino acid or a carboxylic acid is preferred. As a carboxylic acid, a fatty acid is mentioned, for example. Examples of the amino acid include alanine, arginine, aspartame, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, and Aleucine, leucine, lysine, methionine, phenylalanine, valine, serine, threonine, tryptophan, tyrosine, valine. In the present invention, as the organic substance having a carboxyl group, it is particularly preferred to use a fatty acid.

The fatty acid used in the present invention may, for example, be a saturated or unsaturated fatty acid having a carbon number of C3 to C24. In a preferred embodiment, the carbon number may be C3 to C24, more preferably C4 to C22, further preferably C8 to C22, further preferably C12 to C22, and further preferably C16 to C20. Good for C18 carbon number of fatty acids. In a preferred embodiment, fatty acids having a double bond number of, for example, 0 to 4, for example, 0 to 3, for example, 0 to 2, can be used. In view of the fact that the filter is filtered faster, it is particularly preferable that the number of double bonds is one fatty acid. In a preferred embodiment, a fatty acid having a lipophilic property can be used as the fatty acid, and examples of such a fatty acid include fatty acids having the above carbon number.

In a preferred embodiment, as such a fatty acid, it may be selected from the group consisting of crotonic acid, acrylic acid, methacrylic acid, octanoic acid, citric acid, citric acid, lauric acid, myristic acid, pentadecanoic acid, palmitic acid, palm Oleic acid, pearlic acid, stearic acid, oleic acid, isooleic acid, linoleic acid, (9,12,15)-linolenic acid, (6,9,12)-linolenic acid, two high - γ-time linoleic acid, tung acid, tuberculous stearic acid, arachidic acid (icoic acid), 8,11-eicosadienoic acid, 5,8,11-eicosatrienoic acid, peanut four Oleic acid, behenic acid, tetracosic acid, tetracosic acid, oleic acid, sinapic acid, docosahexaenoic acid, eicosapentaenoic acid, stearidonic acid One or more of the group. Further, in the embodiment of the present invention, as the fatty acid, a group selected from the group consisting of stearic acid, oleic acid, linoleic acid and acrylic acid, preferably stearic acid, oleic acid and linoleic acid can be used. 1 of the group More than one species. As the fatty acid, a salt of a fatty acid can be used. In a preferred embodiment, the fatty acid is preferably a salt of a fatty acid itself rather than a fatty acid.

The solvent used in the screen printing paste for electronic materials can be used as the solvent used in the present invention, and examples of such a solvent include an alcohol solvent, a glycol ether solvent, an acetate solvent, a ketone solvent, and a hydrocarbon solvent. Examples of the alcohol solvent include terpineol, isopropyl alcohol, and butyl carbitol. Examples of the terpineol include α-terpineol, β-terpineol, and γ-terpineol, and particularly preferably α-terpineol. Examples of the glycol ether solvent include butyl carbitol. Examples of the acetate solvent include butyl carbitol acetate. As a ketone solvent, methyl ethyl ketone is mentioned, for example. Examples of the hydrocarbon solvent include toluene and cyclohexane. In a preferred embodiment, as a solvent, it can be selected from the group consisting of terpineol, isopropanol, butyl carbitol, butyl carbitol acetate, methyl ethyl ketone, toluene, and cyclohexane. One or more selected from the group consisting of α-terpineol, butyl carbitol, and butyl carbitol acetate can be preferably used.

Regarding the copper powder paste of the present invention, in a preferred embodiment, the mass ratio of the fatty acid to the surface-treated copper powder (fatty acid/surface-treated copper powder) can be, for example, 1/1000 to 1/10. The range is preferably in the range of 1/1000 to 1/20. In a preferred embodiment, the mass ratio of the fatty acid to the solvent (fatty acid/solvent) can be, for example, in the range of 1/100 to 1/10, preferably 1/60 to 1/15. In a preferred embodiment, the mass ratio of the solvent to the surface-treated copper powder (solvent/surface-treated copper powder) can be, for example, in the range of 1/4 to 1/1, preferably 1/3. Range of ~1/1.5.

The adhesive to be used in the present invention can be used as long as it can improve the adhesion to the substrate. Examples of such a binder include a cellulose resin, an epoxy resin, and an acrylic resin. In a preferred embodiment, for example, a polyvinyl acetal resin, a polyvinyl butyral resin, or an acrylate resin can be used.

The operation of preparing the paste by dispersing the surface-treated copper powder, fatty acid or the like in a solvent can be carried out by a known dispersion method, and stirring, kneading, and ultrasonic treatment can be carried out as needed. In a preferred embodiment, the fatty acid may be added to the solvent prior to the addition of the surface treated copper powder or prior to the addition of the surface treated copper powder.

In a preferred embodiment of the present invention, the organic substance having a carboxyl group, preferably a fatty acid, is directly adsorbed on the surface-treated copper powder, and then dispersed in a solvent to form a paste, but to agglomerate, The handleability in the drying step is good, and it is preferred to add the organic substance having a carboxyl group, preferably a fatty acid, to the copper powder in the step of dispersing the surface-treated copper powder in a solvent to form a paste.

In a preferred embodiment of the present invention, after the step of preparing the paste by dispersing the surface-treated copper powder and the fatty acid in a solvent, the step of filtering the prepared paste by a filter is carried out. The purpose of performing the above-described filtration using a filter is to form a fine wiring or an extremely thin conductive layer (electrode) by a copper paste. In a preferred embodiment, the filter may be, for example, a filter having a pore size of 1 to 8 μm, preferably 1 to 5 μm. In a preferred embodiment, the filtration using the filter is carried out by vacuum filtration or pressure filtration. The pressure of the reduced pressure filtration can be, for example, a pressure in the range of 0.1 to 1.0 atm, preferably 0.2 to 0.6. The pressure of the pressure filtration can be, for example, a pressure in the range of 0.1 to 2.0 atm, preferably 0.2 to 1.0.

In a preferred embodiment, the copper powder paste of the present invention is subjected to a vacuum filtration of 0.3 atm in a filter having a pore size of 5 μm and an effective area of 9.0 cm ² , and the percentage of the mass of the permeated mass relative to the input mass of 4 g ( The transmittance can be, for example, 35% or more, 40% or more, 45% or more, 50% or more, or 55% or more after 30 seconds, and after 3 minutes, for example, it can be 35% or more, 40% or more, or 45% or more. 50% or more and 55% or more, for example, after 8 minutes, it may be 40% or more, 45% or more, 50% or more, 55% or more, or 60% or more, and after 15 minutes, for example, it may be 40% or more and 45% or more. 50% or more, 55% or more, and 60% or more.

The filtered copper powder paste is preferably formed by forming a fine wiring or an extremely thin conductive layer (electrode) in terms of an excessively large particle size or agglomerate of the copper powder contained therein. The former copper powder paste is not easily filtered, that is, it is not the particle size of the copper powder contained. If it is small enough and the agglutination is sufficiently lowered, the filtration operation itself becomes difficult due to clogging of the filter or a low recovery rate of the copper paste. The copper powder paste of the present invention is also excellent in that it is easy to carry out the filtration by the filter as described above, and it is possible to achieve a sufficiently high dispersion state of the copper powder. The reason why the copper powder paste of the present invention is excellent in the dispersed state as described above is not clear, but the inventors believe that it may be caused by the excellent surface state of the surface-treated copper powder itself, and further because of the surface treatment. A combination of copper powder and a carboxyl group of an organic substance having a carboxyl group, preferably a fatty acid.

As the copper powder for surface treatment, copper powder produced by a known method can be used. For example, the copper powder may be any of copper powder produced by a dry method or copper powder produced by a wet method. The copper powder produced by the wet method is preferred in terms of always being a wet process prior to the surface treatment of the present invention.

The aqueous solution of amino decane is an aqueous solution of an amino decane which can be used as a decane coupling agent. In a preferred embodiment, the amount of the amino decane used may be 1 g with respect to the mass of the copper powder when the copper powder dispersion is formed, and the mass of the amino decane may be 0.025 g or more, preferably 0.050. The amount of g or more, more preferably 0.075 g or more, further preferably 0.10 g or more, or, for example, may be in an amount of 0.025 to 0.500 g, 0.025 to 0.250 g, or 0.025 to 0.100 g. In a preferred embodiment, the amount of the amino decane used may be set to 1 g with respect to the mass of the copper powder when the copper powder dispersion is formed, and the volume of the amino decane at 25 ° C is 0.01 mL or more. 0.025 mL or more, preferably 0.050 mL or more, more preferably 0.075 mL or more, further preferably 0.10 mL or more, or for example, may be contained in 0.025 to 0.500 mL, 0.025 to 0.250 mL, and 0.025 to 0.100 mL. The amount of the range.

In a preferred embodiment, as the aminodecane, a decane containing one or more amine groups and/or an imido group can be used. The number of the amine group and the imine group contained in the amino decane is, for example, 1 to 4, preferably 1 to 3, and more preferably 1 to 2, respectively. In a preferred embodiment, the number of amine groups and imine groups contained in the amino decane may be one. Aminoguanidine The amino decane in which the total number of the amine group and the imine group contained in the alkane is one may be referred to as monoamine decane in total, and the total of two amino decanes may be referred to as diamino decane in total, which is 3 in total. The amino decane can be especially trialkyl decane. Monoaminodecane and diaminodecane are preferably used in the present invention. In a preferred embodiment, as the aminodecane, a monoamine decane containing one amine group can be used. In a preferred embodiment, the aminodecane may be one having at least one, for example, one, amine group at the terminal of the molecule, preferably a linear or branched chain.

As the amino decane, for example, N-2-(aminoethyl)-3-aminopropylmethyldimethoxydecane, N-2-(aminoethyl)-3-aminopropyl Trimethoxy decane, 3-aminopropyltrimethoxy decane, 1-aminopropyltrimethoxydecane, 2-aminopropyltrimethoxydecane, 1,2-diaminopropyltrimethoxy Baseline, 3-amino-1-propenyltrimethoxydecane, 3-amino-1-propynyltrimethoxydecane, 3-aminopropyltriethoxydecane, 3-triethoxy矽alkyl-N-(1,3-dimethyl-butylene)propylamine, N-phenyl-3-aminopropyltrimethoxydecane, N-(vinylbenzyl)-2-aminoethyl 3-aminopropyltrimethoxydecane, 3-aminopropyltriethoxydecane, 3-aminopropyltrimethoxydecane, N-(2-aminoethyl)-3-amino Propyltrimethoxydecane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxydecane, 3-(N-phenyl)aminopropyltrimethoxydecane.

In a preferred embodiment, the amino decane represented by the following formula I can be used.

H ₂ NR ¹ -Si(OR ² ) ₂ (R ³ ) (Formula I)

In the above formula I, R1 is a linear or branched, saturated or unsaturated, substituted or unsubstituted, cyclic or acyclic, heterocyclic or non-heterocyclic C1 to C12 hydrocarbon The valence group, R2 is an alkyl group of C1 to C5, and R3 is an alkyl group of C1 to C5 or an alkoxy group of C1 to C5.

In a preferred embodiment, R1 of the above formula I is linear or has a branched, saturated or unsaturated, substituted or unsubstituted, cyclic or acyclic, C1 having a heterocyclic ring or no heterocyclic ring. a divalent group of a hydrocarbon of ~C12, and further preferably R1 may be selected from the group consisting of substituted or unsubstituted Substituting a divalent group of a linear saturated hydrocarbon of C1 to C12, a substituted or unsubstituted divalent group of a branched saturated hydrocarbon of C1 to C12, a substituted or unsubstituted linear chain of C1 to C12 a divalent group of an unsaturated hydrocarbon, a divalent group of a substituted or unsubstituted C1 to C12 branched unsaturated hydrocarbon, a substituted or unsubstituted C1 to C12 cyclic hydrocarbon, a divalent group, substituted Or a group of unsubstituted C1 to C12 heterocyclic hydrocarbons, a substituted or unsubstituted C1 to C12 aromatic hydrocarbon divalent group. In a preferred embodiment, R1 of the above formula I is a divalent group of a saturated or unsaturated chain hydrocarbon of C1 to C12, and more preferably a divalent group of a saturated chain hydrocarbon. Further preferably, the atoms at both ends of the chain structure are divalent groups having a free valence. In a preferred embodiment, the carbon number of the divalent group may be, for example, C1 to C12, preferably C1 to C8, preferably C1 to C6, preferably C1 to C3.

In a preferred embodiment, R1 of the above formula I may be selected from the group consisting of -(CH ₂ ) _n -, -(CH ₂ ) _n -(CH) _m -(CH ₂ ) _j-1 -, -(CH ₂ ) _n -(CC)-(CH ₂ ) _n-1 -, -(CH ₂ ) _n -NH-(CH ₂ ) _m -, -(CH ₂ ) _n -NH-(CH ₂ ) _m -NH- (CH ₂ ) _j -, -(CH ₂ ) _n-1 -(CH)NH ₂ -(CH ₂ ) _m-1 -, -(CH ₂ ) _n-1 -(CH)NH ₂ -(CH ₂ ) _M-1 -NH-(CH ₂ ) _j - a group in the group (where n, m, j are integers of 1 or more) (wherein (CC) represents a triple bond of C and C). In a preferred embodiment, R1 can be set to -(CH ₂ ) _n -, or -(CH ₂ ) _n -NH-(CH ₂ ) _m - (wherein (CC) represents the three bonds of C and C ). In a preferred embodiment, the hydrogen of R1 as a divalent group may be substituted with an amine group, or may be substituted by an amine group, for example, 1 to 3 hydrogens, for example, 1 to 2 hydrogens, for example, 1 hydrogen. .

In a preferred embodiment, n, m, and j of the above formula I may each independently be an integer of 1 or more and 12 or less, preferably an integer of 1 or more and 6 or less, and more preferably an integer of 1 or more and 4 or less. For example, it may be an integer selected from 1, 2, 3, and 4, and may be 1, for example, 2 or 3.

In a preferred embodiment, R2 of the above formula I may be an alkyl group of C1 to C5, preferably an alkyl group of C1 to C3, more preferably an alkyl group of C1 to C2, and may be, for example, a methyl group. The ethyl group, the isopropyl group or the propyl group is preferably a methyl group or an ethyl group.

In a preferred embodiment, R3 of the above formula I can be used as an alkyl group. The alkyl group of C1 to C5, preferably an alkyl group of C1 to C3, more preferably an alkyl group of C1 to C2, may be, for example, a methyl group, an ethyl group, an isopropyl group or a propyl group. Set to methyl or ethyl. Further, in R3 of the above formula I, the alkoxy group may be an alkoxy group of C1 to C5, preferably an alkoxy group of C1 to C3, more preferably an alkoxy group of C1 to C2, for example, The methoxy group, the ethoxy group, the isopropoxy group or the propoxy group is preferably a methoxy group or an ethoxy group.

The aqueous solution of the aminodecane can be mixed with the copper powder by a known method. When mixing, stirring can be suitably carried out by a well-known method. In a preferred embodiment, the mixing can be carried out, for example, at room temperature, for example, at a temperature in the range of 5 to 80 ° C, 10 to 40 ° C, and 20 to 30 ° C.

In a preferred embodiment, the copper powder dispersion can be ultrasonically treated after mixing. The treatment time of the ultrasonic treatment is selected according to the state of the copper powder dispersion, and may be preferably 1 to 180 minutes, more preferably 3 to 150 minutes, still more preferably 10 to 120 minutes, and still more preferably 20 ~80 minutes.

In a preferred embodiment, the ultrasonic treatment can be performed at an output of preferably 50 to 600 W, and more preferably 100 to 600 W per 100 mL. In a preferred embodiment, the ultrasonic processing can be performed at a frequency of preferably 10 to 1 MHz, more preferably 20 to 1 MHz, and still more preferably 50 to 1 MHz.

The copper powder in the copper powder dispersion can be subjected to surface treatment with an amino decane as described above, separated from the dispersion, and recovered as a surface-treated copper powder. A known method can be used for the separation and recovery, and for example, filtration, centrifugation, decantation, or the like can be used. After separation and recovery, drying can be carried out as needed. Drying can be carried out by a known method, for example, drying can be carried out by heating. The heat drying can be carried out by, for example, heat treatment at 50 to 90 ° C, 60 to 80 ° C, for example, 30 to 120 minutes, and 45 to 90 minutes. After the heat drying, the copper powder may be further pulverized as needed. Further, in order to prevent rust or to improve the dispersibility in the paste, the surface-treated copper powder may be adsorbed on the surface of the surface-treated copper powder.

As described above, in the preferred embodiment, the copper powder for the surface treatment can be obtained by the wet method. In a preferred embodiment, a copper powder produced by a method for producing a copper powder by a wet method can be used, which comprises adding cuprous oxide to an aqueous solvent containing an additive of gum arabic. In the step of preparing a slurry, a step of adding a dilute sulfuric acid to the slurry at a time within 5 seconds to carry out a heterogeneous reaction. In a preferred embodiment, the slurry may be kept at room temperature (20 to 25 ° C) or less, and a heterogeneous reaction may be carried out by adding dilute sulfuric acid which is also kept at room temperature or lower. In a preferred embodiment, the slurry can be kept at 7 ° C or lower, and the heterogeneous reaction is carried out by adding dilute sulfuric acid which is also kept at 7 ° C or lower. In a preferred embodiment, the addition of dilute sulfuric acid can be carried out so that the pH is 2.5 or less, preferably the pH is 2.0 or less, and further preferably the pH is 1.5 or less. In a preferred embodiment, the addition of dilute sulfuric acid to the slurry can be within 5 minutes, preferably within 1 minute, further preferably within 30 seconds, further preferably within 10 seconds, and further preferably. Add it within 5 seconds. In a preferred embodiment, the above heterogeneous reaction can be set to end over 10 minutes. In a preferred embodiment, the concentration of gum arabic in the slurry can be set to 0.229 to 1.143 g/L. As the cuprous oxide, cuprous oxide, preferably cuprous oxide particles used in a known method, particles of the cuprous oxide particles and the like and particles of copper powder formed by the heterogeneous reaction can be used. There is no direct relationship between the particle size and the like, so that coarse-grained cuprous oxide particles can be used. The principle of the heterogeneous reaction is as follows: Cu ₂ O+H ₂ SO ₄ →Cu↓+CuSO ₄ +H ₂ O

The copper powder obtained by the unevenness can also be washed, rust-proof, filtered, dried, crushed, classified, and mixed with amino decane, but in a preferred embodiment, it can be cleaned as needed. After rust prevention and filtration, it is directly mixed with an aqueous solution of amino decane without drying.

In a preferred embodiment, the copper powder obtained by the above heterogeneous reaction has an average particle diameter of 0.25 μm or less as measured by a laser diffraction type particle size distribution analyzer. In a preferred embodiment, the copper powder obtained by the above heterogeneous reaction utilizes a laser diffraction particle size. D10, D90, and Dmax measured by the distribution measuring device satisfy the relationship of [Dmax ≦ D50 × 3, D90 ≦ D50 × 2, D10 ≧ D50 × 0.5], and the distribution of the particle diameter has a single peak. In a preferred embodiment, the copper powder obtained by the above heterogeneous reaction has a particle size distribution of a peak (having a single peak) in the measurement by a laser diffraction type particle size distribution measuring apparatus. In a preferred embodiment, the value measured by the laser diffraction type particle size distribution measuring device is [D50 ≦ 1.5 μm], preferably [D50 ≦ 1.0 μm], and further preferably [D50 ≦ 0.5 μm, Dmax≦1.0 μm]. As the laser diffraction type particle size distribution measuring apparatus, for example, SALD-2100 manufactured by Shimadzu Corporation can be used.

The surface-treated copper powder obtained in this manner has excellent sintering retardation. As an index of the sintering retardation, there is a sintering initiation temperature. This is a temperature at which a powder compact composed of metal powder is heated in a reducing environment to cause a certain volume change (shrinkage). In the present specification, the temperature at which the volume shrinkage of 1% is caused is set as the sintering initiation temperature. Specifically, the measurement was carried out as described in the examples. The case where the sintering initiation temperature is high indicates that the sintering retardation is excellent.

In a preferred embodiment, the surface-treated copper powder obtained in this manner has a sintering initiation temperature of 450 ° C or higher, preferably 500 ° C or higher, more preferably 600 ° C or higher, and still more preferably 700 ° C or higher, more preferably 780 ° C or higher, further preferably 800 ° C or higher, further preferably 810 ° C or higher, further preferably 840 ° C or higher, further preferably 900 ° C or higher, and further preferably 920 ° C The above is further preferably 950 ° C or higher. The surface treatment is compared with the case where the sintering start temperature of the Ni ultrafine powder (average particle diameter of 0.2 to 0.4 μm) used in the case where the sintering initiation temperature is previously required is in the range of 500 to 600 ° C. The copper powder uses Cu which is cheaper and more readily available than Ni, and is fine particles, and has an excellent sintering retardation equivalent to or higher.

In a preferred embodiment, the surface treated copper powder can be heated in a reducing environment to form a sintered body. The obtained sintered body can be formed into an excellent electrode. This sintering process is particularly preferably used for the fabrication of internal electrodes of wafer-laminated ceramic capacitors. The sintered body is particularly preferably used as an internal electrode of a wafer laminated ceramic capacitor. In a preferred embodiment of the invention, the SiO ₂ particles are dispersed in the electrode cross section to form an extremely thin electrode without degrading the reliability (quality) of the electrode.

In a preferred embodiment, the amount of Si attached to the surface-treated copper powder relative to 1 g of the copper powder is usually 500 to 16,000 μg, preferably 500 to 3000 μg. The Si adhesion amount can be determined by ICP (Inductively Coupled Plasma). In a preferred embodiment, it is further possible to include 0.05% by weight or more of N with respect to the weight of the copper powder. The mechanism by which the decane coupling agent is adsorbed on the copper powder is not clear, but the inventors believe that it is adsorbed by the interaction between the nitrogen of the amine group at the end of the decane coupling agent and copper.

In a preferred embodiment, regarding the surface-treated copper powder, the thickness (Si thickness) of the Si-containing layer formed by the surface treatment can be generally set to 0.6 to 25 nm, preferably 1.0 to 25 nm, and further It is preferably 1.5 to 20 nm. The thickness (Si thickness) of the Si-containing layer is measured by EDS (Energy Dispersive X-ray analysis) by using an EDS (Energy Dispersive X-ray analysis) in a cross section of the surface of the surface-treated copper powder. When the amount of Si atoms present at the maximum depth is 100% with respect to the existence ratio of all atoms, the amount of Si atoms present is set to be 10% or more. Regarding the profile of the surface of the surface-treated copper powder, five of the at least 100 copper powder particles observed in the sample section can be selected, and the sharpest boundary of each of the above is set to be perpendicular to the surface. The cross section of the surface of the treated copper powder was measured and totaled.

In a preferred embodiment, the surface-treated copper powder may have a weight % of N relative to the copper powder of, for example, 0.05% by weight or more, preferably 0.06% by weight or more, and more preferably 0.07% by weight or more. Further, for example, it may be in the range of 0.05 to 0.50% by weight, preferably 0.06 to 0.45% by weight, and more preferably 0.08 to 0.40% by weight. The weight % of N relative to the copper powder allows the copper powder to be melted at a high temperature, and the amount of attached N is calculated from the generated NO ₂ .

In a preferred embodiment, the surface-treated copper powder may be such that, in the survey of XPS (X-ray Photoelectron Spectroscepy) analysis, the surface N is, for example, 1.0% or more, preferably. It is 1.4% or more, more preferably 1.5% or more, further preferably 1.6% or more, or, for example, 1.0 to 6.0%, preferably 1.4 to 6.0%, more preferably 1.5 to 6.0%, still more preferably 1.6. In the range of ~6.0%, the photoelectron of N is, for example, 1000 cps (count per second), preferably 1200 cps or more, or, for example, 1000 to 9000 cps, preferably 1200 to 8000 cps.

In a preferred embodiment, the surface-treated copper powder may be such that, in the Survey measurement by XPS (X-ray photoelectron spectroscopy) analysis, Si on the surface is, for example, 0.6% or more, preferably 0.8% or more, and further It is preferably 1.0% or more, more preferably 1.1% or more, further preferably 1.2% or more, further preferably 1.3% or more, further preferably 1.4% or more, or, for example, 0.6 to 40%, preferably 0.8. ~4.0%, more preferably 1.0 to 4.0%, still more preferably 1.1 to 4.0%, still more preferably 1.2 to 4.0%, still more preferably 1.3 to 4.0%, still more preferably 1.4 to 4.0% The photoelectron of Si is, for example, 1000 cps (count per second) or more, preferably 1200 cps or more, or, for example, 1000 to 12000 cps, preferably 1200 to 12000 cps.

In a preferred embodiment, the surface-treated copper powder may be surface-treated after being surface-treated with an amino decane. As such a surface treatment, for example, an rust-preventing treatment using an organic rust inhibitor such as benzotriazole or imidazole can be used, and even if such a usual treatment is carried out, the surface treatment by the amino decane is not removed. Therefore, the above-mentioned known surface treatment can be carried out as needed within the limits of the excellent sintering retardation. That is, the copper powder and the copper powder paste which are obtained by subjecting the surface of the surface-treated copper powder of the present invention to surface treatment without further deterioration of the sintering retardation are also within the scope of the present invention.

In the case of using the metal powder other than copper powder, the present invention can obtain excellent characteristics by the above surface treatment for copper powder. That is, in the case where it is convenient to use a metal powder other than copper powder, the present invention can be carried out by a preferred embodiment described for the above copper powder. As the metal powder, for example, any one of Pt, Pd, Ag, Ni, and Cu can be used. Preferred metal powders including copper powder include any one of Ag, Ni, and Cu.

The present invention can be preferably carried out as described above by the adhesion of Si, but it can be preferably carried out even by adhesion of elements other than Si. In the case where an element other than Si is attached, the present invention can also be carried out by the preferred embodiment described above for Si. Examples of the element other than Si include any one of Ti, Al, Zr, Ce, and Sn. As a preferable element including Si, any one or more of Si, Ti, Al, Zr, Ce, and Sn, and more preferably any of Si, Ti, and Al is preferable.

The present invention can be preferably carried out by surface treatment with a decane coupling agent as described for the copper powder, but it can also be preferably carried out by surface treatment with a coupling agent other than a decane coupling agent. Examples of the coupling agent other than the decane coupling agent include titanate and aluminate. As the coupling agent, Si can be preferably attached in the case of using a decane coupling agent, Ti can be preferably attached in the case of using a titanate, and Al can be preferably attached in the case of using an aluminate. The use of such coupling agents can be set as described in the decane coupling agent. Similarly to the structure of the decane coupling agent, in the structure of the titanate and the aluminate, it is preferred to have a structure in which a substituent having an amine group at the terminal is bonded to Ti and Al as a central atom.

In a preferred embodiment, the preferred adhesion amount of Si, Ti or Al as the coupling agent is, for example, as described for the copper powder, and further, for example, 200 to 16000 μg with respect to 1 g of the metal powder. The range of 300 to 16000 μg, 500 to 16000 μg, for example, 200 to 3000 μg, 300 to 3000 μg, 500 to 3000 μg, for example, 200 to 1500 μg, 300 to 1500 μg, and 500 to 1500 μg.

In a preferred embodiment, the thickness (Si thickness) of the Si-containing layer formed by the surface treatment of the metal powder can be set as described in the copper powder, and further, the thickness of the Ti-containing layer (Ti thickness), The thickness (Al thickness) of the Al-containing layer may also be set as described for the thickness (Si thickness) of the Si-containing layer.

In a preferred embodiment, the surface treated metal powder can be set to the surface of the XPS (X-ray photoelectron spectroscopy) assay in which the Si is as described for copper powder. Further, in addition to the Si adhered by the surface treatment, Ti and Al may be set to the same numerical range as the numerical range defined for Si by the same measurement method as Si.

In a preferred embodiment, the surface treated metal powder can be set to the surface of the XPS (X-ray photoelectron spectroscopy) assay in which the N of the surface is as described for copper powder.

When a surface-treated metal powder is obtained by using a metal powder other than copper powder, a metal powder paste is prepared by mixing a surface-treated metal powder, an organic substance such as a fatty acid, a solvent, and, if necessary, a binder resin. The steps can be carried out as described for the copper paste. In this case, the kind of the organic substance, the solvent, and the binder resin which can be preferably used, and the mixing ratio are as described for the copper powder paste. The metal powder paste obtained in this manner is in a preferred embodiment, and has the same excellent characteristics as described for the copper powder paste, and has the same excellent filter permeability, workability, sintering delay, and the like. .

As the titanate which can be preferably used in the present invention, an amine group-containing titanate represented by the following formula II: (H ₂ NR ¹ -O) _p Ti(OR ² ) _q (Formula II) )

(wherein, in the above formula II, R1 is a linear or branched, saturated or unsaturated, substituted or unsubstituted, cyclic or acyclic, heterocyclic or non-heterocyclic C1 to C12 hydrocarbon The divalent group, R2 is a linear or branched C1 to C5 alkyl group, p and q are integers of 1 to 3, and p+q=4).

As R1 of the above formula II, a group exemplified as R1 of the above formula I can be preferably used. R1 of the above formula II may, for example, be selected from the group consisting of -(CH ₂ ) _n -, -(CH ₂ ) _n -(CH) _m -(CH ₂ ) _j-1 -, -(CH ₂ ) _n -( CC)-(CH ₂ ) _n-1 -, -(CH ₂ ) _n -NH-(CH ₂ ) _m -, -(CH ₂ ) _n -NH-(CH ₂ ) _m -NH-(CH ₂ ) _j -, -(CH ₂ ) _n-1 -(CH)NH ₂ -(CH ₂ ) _m-1 -, -(CH ₂ ) _n-1 -(CH)NH ₂ -(CH ₂ ) _m-1 -NH -(CH ₂ ) _j - a group in the group (where n, m, j are integers of 1 or more). As a more preferable R1, -(CH ₂ ) _n -NH-(CH ₂ ) _m - (wherein n + m = 4, particularly preferably n = m = 2) can be mentioned.

As R2 of the above formula II, a group exemplified as R2 of the above formula I can be preferably used. In a preferred embodiment, an alkyl group of C3 may be mentioned, and a propyl group and an isopropyl group are particularly preferable.

p and q of the above formula II are integers of 1 to 3, and p + q = 4, preferably a combination of p = q = 2, and a combination of p = 3 and q = 1. The amine group-containing titanate having a functional group as described above is, for example, Plain Act KR44 (manufactured by Ajinomoto Fine-Techno Co., Ltd.).

The metal powder of the present invention has a high sintering initiation temperature as described in the copper powder of the present invention, and by disposing the metal powder, an excellent conductive metal powder paste can be produced by using the conductive metal powder paste By performing sintering, an excellent electrode can be produced. The sintering initiation temperature of the metal powder of the present invention is as described for the copper powder. In a preferred embodiment, the electrode obtained by the present invention can be as described for SiO _{2 of} the electrode profile. Similarly, the TiO ₂ of the electrode profile and the Al ₂ O _{3 of the} electrode profile can also be as The size, number, and density of the SiO _{2 in} the cross section. In a preferred embodiment, the SiO ₂ of the electrode profile corresponds to the case where a decane coupling agent is used as a surface treatment coupling agent, and the TiO ₂ of the electrode profile corresponds to the case where a titanate is used as a surface treatment coupling agent, and the electrode profile is used. Al ₂ O ₃ corresponds to the case where an aluminate is used as a coupling agent for surface treatment.

[Examples]

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

[Manufacture of surface treated copper powder]

The surface-treated copper powder was produced in the following manner.

[Using wet method for milling]

20 g of copper powder for surface treatment was produced by a wet method. The copper powder obtained has the characteristics as described below. For the measurement, a laser diffraction type particle size distribution measuring apparatus (SALD-2100 manufactured by Shimadzu Corporation) was used.

[Preparation of decane aqueous solution]

50 mL each of each of the following decane aqueous solutions of decane was prepared.

矽: diamino decane A-1120 (manufactured by MOMENTIVE)

Amino decane A-1110 (manufactured by MOMENTIVE)

Epoxy decane Z-6040 (manufactured by Dow Corning Toray)

Methyltrimethoxydecane KBM-13 (manufactured by Shin-Etsu Silicones Co., Ltd.)

3-phenylaminopropyltrimethoxydecane (manufactured by MOMENTIVE)

It is prepared in a concentration range of 0.5 to 15 vol%. Further, the pH was adjusted to 4 with dilute sulfuric acid in addition to the amine decane.

The structural formula of various decanes is as follows.

Diaminodecane A-1120: H ₂ NC ₂ H ₄ -NH-C ₃ H ₆ -Si(OCH ₃ ) ₃

Amino decane A-1110: H ₂ NC ₃ H ₆ -Si(OCH ₃ ) ₃

Epoxy decane Z-6040:

Methyltrimethoxydecane KBM-13:H ₃ C-Si(OCH ₃ ) ₃

3-phenylaminopropyltrimethoxydecane: C ₆ H ₅ -NH-C ₃ H ₆ -Si(OCH ₃ ) ₃

[Surface treatment by mixing with decane aqueous solution]

Prepare a copper powder dispersion by mixing 20 g of copper powder with 50 mL of each decane aqueous solution, and immediately perform ultrasonic treatment for 60 minutes (or 120 minutes) (manufactured by Tech Jam Co., Ltd., ultrasonic cleaner, three frequency types) /W-113) (output 100 W, frequency 100 kHz). In Table 1, the time required for the 60 minutes is referred to as the mixing and stirring time. The operation is carried out at room temperature.

Further, as described in Table 1, in some embodiments, stirring or mixing (300 rpm) using a rotary wing is used in combination with the above ultrasonic wave, or the decane coupling agent is adsorbed to copper only by stirring with a rotary wing. powder.

The copper powder dispersion was filtered to recover the surface-treated copper powder, and dried by heating at 70 ° C for 1 hour to obtain a surface-treated copper powder.

The treatments performed by the surface-treated copper powder of each of the examples and the comparative examples are summarized in Table 1.

[Evaluation of surface treated copper powder]

The surface-treated copper powder obtained by the above operation was evaluated in accordance with the following method.

[Measurement of copper powder size]

The size of the copper powder was measured by the following method. The results are summarized in Table 2.

Laser diffraction type particle size distribution measurement (Shimadzu SLAD-2100)

[Measurement by TMA]

A sample was prepared by surface-treated copper powder, and a sintering initiation temperature was measured using a TMA (Thermomechanical Analyzer) under the following conditions.

Sample preparation conditions

Powder compact size: 7 mm ×5 mm high

Molding pressure: 1 Ton/cm ² (1000 kg/cm ² )

(Add 0.5 wt% zinc stearate as lubricant)

Measuring condition

Installation: Shimadzu Corporation TMA-50

Heating: 5 ° C / min

Environment: 2 vol% H ₂ -N ₂ (300 cc/min)

Load: 98.0 mN

As described above, 0.5 wt% of zinc stearate was added to the copper powder to be measured and mixed, and the mixture was packed in a cylinder having a diameter of 7 mm, and pressed into the punch from the upper portion to give 1 Ton/cm ² and kept. Pressurized for 3 seconds, formed into a nearly cylindrical shape with a height of about 5 mm. The molded body was placed in a heating furnace under the condition that the shaft was vertically oriented and given a load of 98.0 mN in the axial direction, and the temperature was raised at a flow rate of 2 vol% H ₂ -N ₂ (300 cc/min). °C/min, continuously measured in the measurement range: 50 to 1000 ° C, and automatically records the height change (change in expansion and contraction) of the molded body. The temperature at which the height change (shrinkage) of the molded body starts and the shrinkage ratio thereof reaches 1% is referred to as "sintering start temperature". The measurement results of the sintering initiation temperatures of the surface-treated copper powders of the respective examples and comparative examples are summarized in Table 3.

[analysis]

The Si, N, and C attached to the surface of the surface-treated copper powder were analyzed under the following conditions. The results are summarized in Table 3.

The amount of adhesion Si is obtained by dissolving the surface-treated copper powder with an acid, and performing ICP (Inductively Coupled Plasma Atomic Emission Spectrometry) to determine the amount of Si attached to the unit mass (g) of the surface-treated copper powder. Quality (μg).

N, C... The copper powder is melted at a high temperature, and the amount of N and C adhered is calculated based on the generated NO ₂ and CO _{2 ,} and the amount of N and C adhering to the entire surface of the copper powder is measured, thereby obtaining the N attached. The mass % (% by weight) of the mass of C relative to the mass of the surface treated copper powder.

In addition to the above Comparative Examples 1 to 4, a comparative experiment was carried out using tetraethoxy decane (TEOS, Tetraethoxy silane) as a decane coupling agent and surface treatment of copper powder using ammonia as a catalyst, using tetraethoxy decane. In the case, it is a state in which the obtained surface-treated copper powder is agglomerated, and it is considered that the surface treatment and the particles are not uniformly obtained by visual observation. path. In this case, before the surface treatment, D50=0.13 μm and Dmax=0.44 μm, but after surface treatment, D50=0.87 μm and Dmax=3.1 μm, both were about 7 times larger. Further, regarding the particle size distribution, one peak is one peak before the surface treatment.

According to these results, the surface-treated copper powder produced by mixing the aqueous solution of the amine-based decane of the present invention is extremely simple, and although it is a minute copper powder, it has the same level as the fine powder of a high-melting-point metal such as nickel. Higher sintering onset temperature. Further, it is understood that the surface-treated copper powder is sintered in the same manner as in the production step of the electrode of the wafer-laminated ceramic capacitor, and the sintered body can be produced, and the SiO ₂ particles are dispersed in the cross section of the sintered body thus produced (formed).

Further, from the above results, it is understood that in order to achieve sufficient sintering retardation, it is necessary to use an amino group-containing decane as a decane coupling agent. Further, it is understood that the amino decane is preferably an amino decane having an amine group at the terminal. In Comparative Example 4, although it was observed that a sufficient amount of Si was adhered to the copper powder, sufficient sintering retardation was not achieved. Although the reason for this is not clear, the inventors presumed that the reason may be that, in Comparative Example 4, the amino decane did not have a structure having an amine group at the terminal, and the benzene ring was present at the end closer to the amine group, thus producing In the state of steric hindrance, the amino decane or Si temporarily attached to the copper powder is detached from the copper powder at an early stage in the middle of the temperature rise for sintering.

[Coherent Manufacturing by Wet Method]

The fine copper powder was produced as follows, and the surface-treated copper powder of the present invention was subjected to a wet-process continuous production by surface-treating the produced copper powder with an amino decane.

(1) 50 g of cuprous oxide was added to a gum arabic 0.2 g + pure water 350 mL.

(2) Then, dilute sulfuric acid (25 wt%) 50 mL was added in one portion.

(3) After stirring with a rotary wing (300 rpm × 10 minutes), it was left for 60 minutes.

(4) Then, the precipitate is cleaned.

The cleaning is carried out by first removing the supernatant and adding 350 mL of pure water and stirring (300 rpm × 10 minutes), leaving it for 60 minutes, removing the supernatant and adding 350 mL of pure water. After stirring (300 rpm × 10 minutes), it was allowed to stand for 60 minutes, and the supernatant was removed.

(5) Subsequently, treatment with an amino decane was carried out.

Amino decane treatment was carried out by adding an aqueous solution of amino decane (50 mL) and stirring for 60 minutes, at which time a rotary wing (300 rpm) + ultrasonic wave (manufactured by Tech Jam Co., Ltd., ultrasonic cleaner, three frequency types/W) -113) (output 100 W, frequency 100 kHz) processing. In contrast to this, only the processing of the rotary wing (300 rpm) is performed, and only the ultrasonic processing is performed. As the amino decane, diamino decane A-1120 (manufactured by MOMENTIVE Co., Ltd.) and amino decane A-1110 (manufactured by MOMENTIVE Co., Ltd.) were used.

(6) Then, filtration was carried out to separate the precipitate.

(7) The separated precipitate is then dried. Drying (70 ° C × 2 h) was carried out in a dry atmosphere and drying in nitrogen.

The surface-treated fine copper powder is obtained by continuous production in this manner. The surface-treated copper powder obtained in this manner has excellent sintering retardation similarly to the surface-treated copper powder of the above-described embodiment, and the number of large particles of SiO ₂ present in the cross section of the sintered body is small. . Moreover, this continuous production can be carried out without drying before obtaining the final product, which is simple and excellent in workability.

[Manufacture of copper powder paste]

Each of the aminoguanidine-treated copper powders produced in Examples 2, 3, and 5 and Comparative Examples 1 and 2, each of the following fatty acids, and a binder were dispersed in a solvent to prepare 20 g of a copper powder paste. At this time, the surface treatment copper powder: solvent: binder: the mass ratio of the fatty acid is set to 65:34.3:0.7 when no binder is added, and 65:27.2:7:0.8 when the binder is added. . These were used as Examples 9, 10, and 11 and Comparative Examples 5 and 6, respectively, for subsequent measurement.

Surface treated copper powder of Example 2: treatment with diamine decane having a decane concentration of 2 vol%

Surface-treated copper powder of Example 3: treatment with diamine decane having a decane concentration of 4 vol%

Surface-treated copper powder of Example 5: treatment with diamine decane having a decane concentration of 10 vol%

Surface treated copper powder of Comparative Example 1: only BTA (benzotriazole, benzotriazole) treatment

Surface treated copper powder of Comparative Example 2: treatment with epoxy decane having a decane concentration of 10 vol%

Fatty acid: oleic acid (C18, one double bond) linoleic acid (C18, two double bonds) acrylic acid (C3, one double bond)

Adhesive: Polyvinyl butyral resin

Solvent: α-terpineol (TPO) or butyl carbitol

In the above-mentioned preparation, the surface-treated copper powder, the fatty acid, the binder, and the solvent were kneaded by a three-roller to obtain an internal electrode paste.

[Determination of transmittance by filter filtration]

The copper powder paste produced as described above was filtered under reduced pressure at 0.2 atm in a glass filter having a pore size of 5 μm, and the amount of permeation after 30 seconds, 8 minutes, and 15 minutes from the time of initial introduction was measured. The ratio of the amount (g) initially charged to the filter was calculated as a percentage, and the transmittance (%) was set. The results obtained in Examples 9, 10, and 11, and Comparative Examples 5 and 6 (with and without a binder resin) are shown in Tables 4 and 5 below.

As described above, it was found that the copper powder surface-treated with diamine decane showed a significantly excellent transmittance of at least 9 to 10 times or more under any of the conditions.

The above-mentioned filter-filtered copper powder paste is applied to a sheet of a paste of a dielectric powder at a thickness of about 1 μm, whereby a uniform sheet of the copper powder paste can be obtained relatively easily. By sintering this, an electrode can be produced in a state where the dielectric layer and the conductive layer formed of copper are not peeled off.

The smaller the copper powder particle size, the more obvious the agglomeration. Further, if agglomeration occurs as described above, the workability and productivity are lowered only in this way. Further, in the case of forming an internal electrode of a wafer-stacked ceramic capacitor, a printing technique such as screen printing is used. Therefore, it is necessary to filter the copper powder paste containing copper powder particles by a filter having a small pore size before printing. However, if copper powder having a small particle size is used for precise printing, aggregation tends to occur, and if the copper powder is aggregated in the copper powder paste, the electrode pattern cannot be printed by the filter. When the filter is clogged, not only the utilization efficiency (recovery rate) of the copper paste is lowered, but also the entire printing apparatus must be stopped in order to replace the filter. Therefore, it is important to prevent the agglomeration of copper powder in the electrode manufacturing.

In the above case, it is understood that the copper powder paste of the present invention is excellent in sintering retardation, prevents aggregation, and has excellent filter permeability. Therefore, it is preferably used as an electrode manufacturer using a printing technique.

[Manufacture of copper powder treated by anti-rust treatment]

A copper powder which is subjected to rust-proof treatment of the surface-treated copper powder. After the copper powder of the above Example 4 was obtained, it was dispersed in 100 mL of an aqueous benzotriazole solution (0.1 g/L) for rust-preventing treatment, and stirred at 500 rpm for 10 minutes using a rotary blade to carry out filtration and drying ( Under a nitrogen atmosphere, 70 ° C × 1 h), copper powder subjected to rust prevention treatment was further obtained (Example 12).

[Evaluation of copper powder by anti-rust treatment]

The rust-proof copper powder (Example 12) was evaluated in the same manner as in Example 4, and the results are summarized in Tables 6 to 8. Further, the size of the treated copper powder in Table 7 was the size of the copper powder after the rust-preventing treatment in Example 12, and the evaluations in Table 8 were also the results for the rust-proof treated copper powder. According to these results, even in the case where the surface-treated copper powder is subjected to rust-preventing treatment, the excellent characteristics of the surface-treated copper powder are not lost.

[Examples]

In addition to the embodiments described above, the following examples are also given to illustrate the invention in more detail. The invention is not limited to the following examples.

[metal powder]

As the metal powder, copper fine powder, nickel powder, and silver powder were prepared in accordance with the following procedures.

(copper powder)

‧Examples 18-20, Comparative Example 11

20 g of copper powder for surface treatment was produced by the above wet method. which is,

(1) 50 g of cuprous oxide was added to a gum arabic 0.4 g + pure water 350 mL.

(2) Then, dilute sulfuric acid (25 wt%) 50 mL was added in one portion.

(3) After stirring with a rotary wing (300 rpm × 10 minutes), it was left for 60 minutes.

(4) Then, the precipitate is cleaned.

The cleaning system initially removes the supernatant and adds 350 mL of pure water and stirs (300 rpm × 10 minutes), then left for 60 minutes, removes the supernatant and adds 350 mL of pure water to stir (300 rpm × 10 After leaving for 60 minutes, the copper fine powder was precipitated. In this state, the particle size measurement was carried out by laser diffraction type particle size distribution measurement (Shimadzu Corporation SLAD-2100), and the particle size measurement before surface treatment was performed.

The particle size (D50, Dmax) of the obtained copper powder is shown in Table 7. For the measurement, a laser diffraction type particle size distribution measuring apparatus (SALD-2100 manufactured by Shimadzu Corporation) was used.

‧Example 13

Copper powder is obtained by a chemical reduction method according to Japanese Patent No. 4164009. Namely, 2 g of gum arabic was added to 2900 mL of pure water, and then 125 g of copper sulfate was added thereto while stirring, and 360 mL of 80% hydrazine monohydrate was added thereto. After the addition of the hydrazine monohydrate, the temperature was raised from room temperature to 60 ° C over 3 hours, and the copper oxide was allowed to react over 3 hours. After completion of the reaction, the obtained slurry was filtered through a Nutsche funnel, followed by washing with pure water and methanol, and further drying to obtain copper powder. The copper powder was mixed with an aqueous solution of a diamine decane coupling agent in accordance with the procedure of Example 1 to obtain a surface-treated copper powder. The characteristics were evaluated in accordance with the procedure of Example 1.

(nickel powder)

The nickel powder was NF32 (D50 of 0.3 μm) manufactured by Toho Titanium.

(silver powder)

Milling was carried out in accordance with Japanese Patent Laid-Open No. 2007-291513. That is, 12.6 g of silver nitrate was dissolved in 0.8 L of pure water, 24 mL of 25% ammonia water was added, and 40 g of ammonium nitrate was further added to prepare an aqueous solution of the amine silver wrong salt. Gelatin was added in an amount of 1 g/L as an electrolyte, and a DSE (Dimensionally Stable Electrode) plate was used for both the anode and the cathode, and the current density was 200 A/m ² and the solution temperature was 20 ° C. Electrolysis was carried out while electrolyzing silver particles were scraped off from the plates for one hour. The silver powder thus obtained was filtered using a Nunch funnel, washed in the order of pure water and alcohol, and dried at 70 ° C for 12 hours in an atmosphere. The silver powder was subjected to dry classification to finally obtain a silver powder having a D50 of 0.1 μm and a Dmax of 0.5 μm.

(Preparation of coupling agent aqueous solution)

50 mL each of each of the following decane aqueous solutions of decane was prepared.

矽: diamino decane A-1120 (manufactured by MOMENTIVE) Methyltrimethoxydecane KBM-13 (manufactured by Shin-Etsu Silicones Co., Ltd.)

Titanate: Amine-based Plain Act KR44 (manufactured by Ajinomoto Fine-Techno Co., Ltd.) Amine-free Plain Act KR TTS (manufactured by Ajinomoto Fine-Techno Co., Ltd.)

It is prepared in a concentration range of 1 to 10 vol%. Further, the pH was adjusted to 4 with dilute sulfuric acid in addition to the amine coupling agent.

The structural formula of various decanes is as follows.

Diaminodecane A-1120: H ₂ NC ₂ H ₄ -NH-C ₃ H ₆ -Si(OCH ₃ ) ₃

Methyltrimethoxydecane KBM-13:H ₃ C-Si(OCH ₃ ) ₃

Amine-based Plain Act KR44

Side chain organic functional group (CH ₃ ) ₂ CH-O- of hydrophobic group

Hydrophilic side chain organofunctional group -O-(C ₂ H ₄ )-NH-(C ₂ H ₄ )-NH ₂

Amine-free Plain Act KR TTS

Side chain organic functional group (CH ₃ ) ₂ CH-O- of hydrophobic group

Hydrophilic side chain organic functional group -O-CO-(C ₁₇ H ₃₅ )

(surface treatment)

Remove the supernatant from the copper micronized slurry obtained in the above (copper powder) process, without making copper The fine powder was dried and mixed with the coupling agent prepared in the above (preparation of a coupling agent aqueous solution) by any of the following methods (Examples 18 to 20, Comparative Example 11).

(1) Rotating wing (300 rpm) + ultrasonic (manufactured by Tech Jam Co., Ltd., ultrasonic cleaner, 3 frequency types / W-113) (output 100 W, frequency 100 kHz)

(2) Rotary wing only (300 rpm)

(3) Ultrasonic only

Then, each of the coupling agent aqueous solutions was suction-filtered by an aspirator, and then dried at 70 ° C for 1 hour in a nitrogen atmosphere, and pulverized by a mortar. The particle size measurement was performed again in this state.

The nickel powder obtained in the above (nickel powder) and the silver powder obtained by the above (silver powder) process are mixed for 60 minutes and mixed with the coupling agent prepared in the above (preparation of the coupling agent aqueous solution) according to the above step (1). The surface treatment was carried out (Examples 14 to 17 and 21 to 26, and Comparative Examples 8, 10, 12, and 13).

[Manufacture of metal powder paste]

The metal powder paste 20 was prepared by dispersing each of the aminoguanidine-treated metal powders, the following respective fatty acids, and a binder produced in Examples 14, 16, 19, 22, and 25 and Comparative Examples 7 to 11 in a solvent. g. The surface treatment metal powder at this time: solvent: binder: the mass ratio of the fatty acid is set to 65:34.3:0.7 in the case where no binder is added, and 65:27.2:7:0.8 in the case of adding the binder. These were used as Examples 27 to 31 and Comparative Examples 14 to 18, respectively, for subsequent measurement.

Surface-treated nickel powder of Example 14: treatment with diamine decane having a decane concentration of 1 vol%

Surface-treated silver powder of Example 16: treatment with diamine decane having a decane concentration of 1 vol%

Surface-treated copper powder of Example 19: treatment with an amine group-containing titanate having a titanate concentration of 6 vol%

Surface-treated nickel powder of Example 22: treatment of an amine group-containing titanate having a titanate concentration of 6 vol%

Surface-treated silver powder of Example 25: treatment of an amine group-containing titanate having a titanate concentration of 6 vol%

Silver powder of Comparative Example 7: no surface treatment

Surface-treated silver powder of Comparative Example 8: treatment with methyltrimethoxydecane having a decane concentration of 10 vol%

Nickel powder of Comparative Example 9: no surface treatment

Surface-treated nickel powder of Comparative Example 10: treatment with methyltrimethoxydecane having a decane concentration of 10 vol%

Surface-treated copper powder of Comparative Example 11: Treatment with titanate having a decane concentration of 10 vol% without an amine group

Fatty acid: oleic acid (C18, one double bond) linoleic acid (C18, two double bonds) acrylic acid (C3, one double bond)

Adhesive: Polyvinyl butyral resin

Solvent: α-terpineol (TPO) or butyl carbitol

In the above-mentioned preparation, the surface-treated metal powder, the fatty acid, the binder, and the solvent were kneaded by a three-roller to obtain an internal electrode paste.

[Determination of transmittance by filter filtration]

The metal powder paste produced as described above was filtered under reduced pressure at 0.2 atm in a glass filter having a pore size of 5 μm, and the amount of permeation after 30 seconds, 8 minutes, and 15 minutes from the time of initial introduction was measured. The ratio of the amount (g) initially charged to the filter was calculated as a percentage, and the transmittance (%) was set. The results obtained in Examples 27 to 31 and Comparative Examples 12 to 16 (with and without a binder resin) are shown in Tables 9 and 10 below.

According to the results, it is known that when a metal powder other than copper powder is used and a surface-treated metal powder is produced using a coupling agent other than amino decane, it can also be used as a copper powder surface-treated with an amino decane. In the same manner, a person having a higher sintering initiation temperature is formed by an extremely simple manufacturing method. Further, it is understood that a sintered body can be produced by sintering the surface-treated metal powder in the same manner as in the step of manufacturing the electrode of the wafer-laminated ceramic capacitor. In addition, in the same manner as in the case of the copper powder paste, the metal powder paste produced by the surface-treated metal powder is excellent in retardation resistance and also prevents aggregation, and the filter permeability is also excellent. It is preferably used for electrode fabrication using printing techniques.

[Industrial availability]

The copper powder paste of the present invention is excellent in sintering retardation and excellent in dispersibility of copper powder in the paste. Therefore, it is possible to avoid the problem of production such as electrode peeling and facilitate the production of the electrode for a wafer laminated capacitor. Further, since the copper powder paste of the present invention can be produced by subjecting the surface-treated copper powder to a very simple treatment, it does not require a superior skill, and is excellent in workability and productivity. Further, the metal powder paste of the present invention has excellent characteristics similarly to the copper powder paste. The invention is produced An invention that is useful in the industry.

Claims (56)

A metal powder paste which is dispersed in a solvent and comprises a surface-treated metal powder in which an adhesion amount of any one of Si, Ti, Al, Zr, Ce, and Sn is 200 to 1 g of the metal powder. 16,000 μg, the weight % of N relative to the metal powder is 0.02% or more; and an organic substance having a carboxyl group. The metal powder paste of claim 1, wherein the surface-treated metal powder and the organic substance having a carboxyl group are dispersed in a solvent to contain a binder resin. For example, the metal powder paste of claim 1 or 2, wherein the metal powder is copper powder. For example, the metal powder paste of the first or second aspect of the patent application, wherein the metal powder is any one of Pt, Pd, Ag, Ni, and Cu. The metal powder paste of claim 1 or 2, wherein the adhesion amount of any one or more of Si, Ti, Al, Zr, Ce, and Sn is 300 to 16000 μg with respect to 1 g of the metal powder. The metal powder paste of claim 1 or 2, wherein the adhesion amount of any one of Si, Ti, Al, Zr, Ce, and Sn is 500 to 16000 μg with respect to 1 g of the metal powder. The metal powder paste of the first or second aspect of the patent application, wherein the adhesion amount of any one or more of Si, Ti, Al, Zr, Ce, and Sn is 3000 μg or less with respect to 1 g of the metal powder. The metal powder paste of the first or second aspect of the patent application, wherein the adhesion amount of any one or more of Si, Ti, Al, Zr, Ce, and Sn is 1500 μg or less with respect to 1 g of the metal powder. For example, the metal powder paste of claim 1 or 2, wherein the weight % of N relative to the metal powder is 0.05% or more. The metal powder paste of claim 1 or 2, wherein any one or more of Si, Ti, Al, Zr, Ce, and Sn is at least one of Ti, Al, Zr, Ce, and Sn. The metal powder paste of claim 1 or 2, wherein any one of Si, Ti, Al, Zr, Ce, and Sn is Si. For example, in the metal powder paste of claim 1, wherein the metal powder is copper powder, the adhesion amount of Si is 500 to 16000 μg with respect to 1 g of copper, and the weight % of N relative to copper powder is 0.05% or more. For example, in the metal powder paste of claim 1, wherein the metal powder is copper powder, the adhesion amount of Si is 500 to 3000 μg with respect to 1 g of copper, and the weight % of N relative to copper powder is 0.05% or more. The metal powder paste according to any one of the preceding claims, wherein the surface-treated metal powder is a metal powder surface-treated with a coupling agent. The metal powder paste of any one of the first, the second, the 12th, and the 13th, wherein the catalyst is adsorbed by Si, Ti, Al, Zr, Ce, and Sn. Any one or more. The metal powder paste according to any one of the preceding claims, wherein the coupling agent is any one of decane, titanate or aluminate. The metal powder paste according to any one of the preceding claims, wherein the coupling agent is a coupling agent having an amine group at the end. The metal powder paste according to any one of the preceding claims, wherein the coupling agent is an amino decane. The metal powder paste according to any one of the preceding claims, wherein the organic substance having a carboxyl group is a carboxylic acid or an amino acid. The metal powder paste according to any one of the first aspect, the second item, the item 12, and the item 13, wherein the organic substance having a carboxyl group is a fatty acid. For example, the metal powder paste of claim 20, wherein the fatty acid is a saturated or unsaturated fatty acid of C3~C24. For example, the metal powder paste of claim 20, wherein the fatty acid is a fatty acid having a double bond number of C3 to C24 of 0-2. The metal powder paste of claim 20, wherein the fatty acid is selected from the group consisting of crotonic acid, acrylic acid, methacrylic acid, octanoic acid, citric acid, citric acid, lauric acid, myristic acid, pentadecanoic acid, Palmitic acid, palmitoleic acid, pearlic acid, stearic acid, oleic acid, isooleic acid, linoleic acid, (9,12,15)-linolenic acid, (6,9,12)-linolenic oil Acid, di-high-gamma-linolenic acid, tungstic acid, tuberculous stearic acid, arachidic acid (icoic acid), 8,11-eicosadienoic acid, 5,8,11-eicosatriene Acid, arachidonic acid, behenic acid, tetracosic acid, tetracosic acid, oleic acid, sinapic acid, docosahexaenoic acid, eicosapentaenoic acid, octadecaene One or more of the group consisting of acids. The metal powder paste of any one of the first, the second, the 12th, and the 13th, wherein the solvent is an alcohol solvent, a glycol ether solvent, an acetate solvent, a ketone solvent or a hydrocarbon solvent. For example, the metal powder paste of claim 20, wherein the mass ratio of the fatty acid to the surface-treated metal powder (fatty acid/surface-treated metal powder) is in the range of 1/100 to 1/10. For example, the metal powder paste of claim 20, wherein the mass ratio of the fatty acid to the solvent (fatty acid/solvent) is in the range of 1/100 to 1/10. The metal powder paste according to any one of the first, second, twelfth, and thirteenth aspects of the patent application, wherein the filter having a pore diameter of 5 μm and an effective area of 9.0 cm ² is subjected to a vacuum filtration of 0.3 atm. At the time, the percentage (transmittance) of the ratio of the mass of the permeation to the input mass of 4 g was 35% or more after 30 seconds. A wafer-stacked ceramic capacitor manufactured by using the paste of any one of claims 1 to 27. A wafer-stacked ceramic capacitor according to claim 28, wherein any one of SiO ₂ , TiO ₂ , and Al ₂ O ₃ having a diameter of 10 nm or more is present in the internal electrode cross section. The patent application scope wafer Item 28 or Item 29 of the multilayer ceramic capacitor, wherein the ² or less 0.5 / cm there is a maximum diameter less than the 0.5μm SiO,, any one of Al ₂ O ₃ in the ₂ Ti02 ₂ internal electrode cross-sectional One. A method for manufacturing a metal powder paste, comprising the steps of: Preparing a paste by dispersing a surface-treated metal powder and an organic substance having a carboxyl group in a solvent, and the amount of adhesion of any one of Si, Ti, Al, Zr, Ce, and Sn in the surface-treated metal powder is 1 g relative to the metal powder It is 200 to 16000 μg, and the weight % of N with respect to the metal powder is 0.02% or more. The method of claim 31, wherein the step of preparing the paste is a step of preparing a paste by dispersing the binder resin in a solvent in addition to the surface-treated metal powder and the organic substance having a carboxyl group. The method of claim 31, wherein the organic substance having a carboxyl group is a fatty acid. The method of claim 31 or 32, wherein the step of preparing a paste by dispersing the surface-treated metal powder and the fatty acid in a solvent comprises the step of filtering the prepared paste by a filter. The method of claim 34, wherein the filter has a pore size of 1 to 8 μm. The method of claim 34, wherein the step of filtering by a filter is performed by vacuum filtration or pressure filtration. The method of claim 31, wherein the surface-treated metal powder is obtained by a method for producing a surface-treated metal powder comprising the steps of: metal powder and an amine group The step of preparing a metal powder dispersion by mixing an aqueous solution of the mixture. The method of claim 37, wherein the metal powder is any one of Pt, Pd, Ag, Ni, and Cu. For example, the method of claim 37, wherein the metal powder is copper powder. The method of claim 37, wherein the metal powder is any one of Pt, Pd, Ag, and Ni. The method of claim 37, which comprises the step of agitating the metal powder dispersion. The method of claim 37, which comprises the step of ultrasonically treating the metal powder dispersion. For example, in the method of claim 42, wherein the step of performing ultrasonic processing is a step of performing ultrasonic processing for 1 to 180 minutes. The method of claim 37, comprising the steps of: filtering the metal powder dispersion to recover the metal powder; and drying the filtered metal powder to obtain the surface-treated metal powder. The method of claim 44, wherein the drying is carried out in an oxygen atmosphere or an inert atmosphere. The method of claim 37, wherein the metal dispersion comprises 0.025 g or more of an amine group-containing coupling agent relative to 1 g of the metal powder. The method of claim 37, wherein the aqueous solution of the amino decane is an aqueous solution of the amino decane represented by the following formula I: H ₂ NR ¹ -Si(OR ² ) ₂ (R ³ ) (Formula I) (wherein , in the above formula I, R1 is a linear or branched, saturated or unsaturated, substituted or unsubstituted, cyclic or acyclic, heterocyclic or non-heterocyclic C1 to C12 hydrocarbon The valence group, R2 is an alkyl group of C1 to C5, and R3 is an alkyl group of C1 to C5 or an alkoxy group of C1 to C5. The method of claim 47, wherein R1 is selected from the group consisting of -(CH ₂ ) _n -, -(CH ₂ ) _n -(CH) _m -(CH ₂ ) _j-1 -, -(CH ₂ ) _n -(CC)-(CH ₂ ) _n-1 -, -(CH ₂ ) _n -NH-(CH ₂ ) _m -, -(CH ₂ ) _n -NH-(CH ₂ ) _m -NH-(CH _{2 j} -, -(CH ₂ ) _n-1 -(CH)NH ₂ -(CH ₂ ) _m-1 -, -(CH ₂ ) _n-1 -(CH)NH ₂ -(CH ₂ ) _m-1 a group in the group consisting of -NH-(CH ₂ ) _j - (wherein n, m, and j are integers of 1 or more). The method of claim 37, wherein the aqueous solution of the coupling agent is an aqueous solution of an amine group-containing titanate represented by the following formula II: (H ₂ NR ¹ -O) _p Ti(OR ² ) _q (Formula II Wherein, in the above formula II, R1 is linear or has a branched, saturated or unsaturated, substituted or unsubstituted, cyclic or acyclic, heterocyclic or non-heterocyclic C1~C12 a divalent group of a hydrocarbon, R2 is a linear or branched C1 to C5 alkyl group, p and q are integers of 1 to 3, and p+q=4). The method of claim 49, wherein R1 is selected from the group consisting of -(CH ₂ ) _n -, -(CH ₂ ) _n -(CH) _m -(CH ₂ ) _j-1 -, -(CH ₂ ) _n -(CC)-(CH ₂ ) _n-1 -, -(CH ₂ ) _n -NH-(CH ₂ ) _m -, -(CH ₂ ) _n -NH-(CH ₂ ) _m -NH-(CH _{2 j} -, -(CH ₂ ) _n-1 -(CH)NH ₂ -(CH ₂ ) _m-1 -, -(CH ₂ ) _n-1 -(CH)NH ₂ -(CH ₂ ) _m-1 a group in the group consisting of -NH-(CH ₂ ) _j - (wherein n, m, and j are integers of 1 or more). The method of claim 31, wherein the metal powder is manufactured by a wet method. The method of claim 31, wherein the surface-treated metal powder is as follows: the adhesion amount of any one of Si, Ti, Al, Zr, Ce, and Sn is 1 g relative to the metal powder 200 to 16000 μg, and the weight % of N with respect to the metal powder is 0.02% or more; and the sintering initiation temperature is 400 ° C or more. A method for producing an electrode, comprising the steps of: applying a metal powder paste prepared by the production method according to any one of claims 31 to 52 to a substrate; and coating the substrate on the substrate The conductive metal paste is subjected to a step of heating and calcining. The method of claim 53, wherein the electrode is an electrode for a wafer-stacked ceramic capacitor. A metal powder paste obtained by the production method according to any one of claims 31 to 52, which is reduced by 0.3 atm in a filter having a pore diameter of 5 μm and an effective area of 9.0 cm ² . In the case of pressure filtration, the percentage (transmittance) of the ratio of the mass of the permeate to the input mass of 4 g was 35% or more after 15 minutes. An electrode obtained by the manufacturing method of claim 53 or 54 and having SiO ₂ , TiO ₂ , Al having a maximum diameter of 0.5 μm or more in an electrode cross section of 0.5/cm ² or less Any of ₂ O ₃ .