WO2016052373A1 - Copper powder - Google Patents

Copper powder Download PDF

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Publication number
WO2016052373A1
WO2016052373A1 PCT/JP2015/077253 JP2015077253W WO2016052373A1 WO 2016052373 A1 WO2016052373 A1 WO 2016052373A1 JP 2015077253 W JP2015077253 W JP 2015077253W WO 2016052373 A1 WO2016052373 A1 WO 2016052373A1
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WO
WIPO (PCT)
Prior art keywords
copper powder
copper
mass
raw material
resin
Prior art date
Application number
PCT/JP2015/077253
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French (fr)
Japanese (ja)
Inventor
隆 向野
善仁 後藤
Original Assignee
三井金属鉱業株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by 三井金属鉱業株式会社 filed Critical 三井金属鉱業株式会社
Priority to JP2016551999A priority Critical patent/JP6303022B2/en
Publication of WO2016052373A1 publication Critical patent/WO2016052373A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C9/00—Alloys based on copper
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/20—Conductive material dispersed in non-conductive organic material
    • H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B5/00—Non-insulated conductors or conductive bodies characterised by their form

Definitions

  • the present invention relates to copper powder.
  • Copper powder is suitably used as a raw material for conductive compositions such as conductive paste.
  • the conductive composition is obtained by dispersing copper powder in a vehicle containing a binder resin and an organic solvent.
  • the conductive composition is used, for example, for forming an electric circuit or forming an external electrode of a ceramic capacitor.
  • Patent Document 2 describes a copper powder containing any one of Al, Mg, Ge, and Ga.
  • the copper powder described in Patent Documents 1 and 2 the copper powder is prevented from being oxidized by containing an element other than copper in the copper powder. Therefore, the element contained in the copper powder remains in the conductor formed from the conductive composition containing the copper powder. Depending on how the conductor is used and where it is used, the use of copper powder may be limited because the element may adversely affect the bonding reliability and conduction characteristics.
  • the object of the present invention is to improve copper powder. More specifically, the surface stability is excellent without using different elements, the denseness of the conductive composition, the adhesion with the oxygen-containing insulating material, and the uniform distribution. The object is to provide copper powder with excellent properties.
  • the present invention provides a peak intensity P 1 of Cu (I) with respect to a peak intensity P 2 of Cu (II) and A copper powder having a value of P 2 / (P 0 + P 1 ), which is a ratio of the peak intensity P 0 of Cu (0), is 0.15 or more and 1 or less.
  • this invention is as a suitable manufacturing method of the said copper powder, Copper which performs oxidation treatment by leaving the dried raw material copper powder to stand for 20 minutes or more and 650 minutes or less in an air atmosphere having a relative humidity of 40% RH to 80% RH and a temperature of 20 ° C to 120 ° C.
  • a method for producing a powder is provided.
  • the copper powder of the present invention is composed of an aggregate of copper particles.
  • the copper powder of the present invention consists essentially of copper particles, but it is allowed to contain inevitable impurities. Moreover, you may make the copper powder of this invention contain other powders etc. as needed.
  • the copper powder of this invention has one of the characteristics in the oxidation state of the copper which exists in the surface of a copper particle.
  • the copper particles constituting the copper powder of the present invention are metallic copper (that is, Cu (0)), monovalent copper (that is, Cu (I)), and divalent copper (that is, Cu) on the surface of the copper particles.
  • the ratio of (II)) is unique.
  • the abundance ratio of copper having various valences can be measured using an X-ray photoelectron spectrometer (XPS). According to XPS measurement, X-ray photoelectron spectroscopy spectra of various elements are obtained. In XPS, quantitative analysis can be performed on elemental components at a depth of about 10 nm from the surface of the copper particles.
  • the ratio of P 2 / (P 0 + P 1 ), which is the ratio of the peak intensity P 0 of Cu (0), is preferably 0.15 or more and 1 or less, more preferably 0.3 or more and 0.9 or less. Yes, more preferably 0.4 or more and 0.7 or less.
  • the value of P 2 / (P 1 + P 0 ) is referred to as “copper oxidation rate”.
  • the peak intensity is the height of the peak.
  • the peak of Cu (II) is mainly derived from CuO and Cu (OH) 2 and is observed in the range of 934.0 eV or more and 936.0 eV or less. Since these peaks are observed at the same position, they cannot be distinguished from each other.
  • the peak of Cu (I) is mainly derived from Cu 2 O.
  • the Cu (0) peak is derived from metallic copper. Since the peak of Cu (I) and the peak of Cu (0) are observed at the same position in the range of 930.0 eV to 933.5 eV, the two cannot be separated. Therefore, in the present invention, the definition of the copper oxidation rate is as described above.
  • the conductor obtained from the conductive composition containing the copper powder of the present invention can be made into a dense structure.
  • the affinity between the conductive composition and the oxygen-containing insulating material is high, the adhesion of the electronic component to the base material or the dielectric material is increased, and an electronic component with high adhesion reliability can be obtained. Therefore, the electrode for electronic components can be suitably manufactured using the copper powder of the present invention.
  • the conductive composition contains glass frit
  • the familiarity between the copper particles, the ceramic material, and the glass frit is improved when the conductive composition is used as an electrode of a ceramic electronic component. Therefore, when used as a conductive composition for ceramic electronic components that require sintering, it is possible to effectively prevent segregation of glass components during sintering. This also allows the conductor to have a dense structure.
  • the copper powder of this invention does not contain dissimilar elements other than copper substantially, it has an advantage also in the point that there are few restrictions of a use scene. “Substantially free of different elements” means that when the copper powder is subjected to elemental analysis, the total content of different elements other than copper and oxygen is 0.1% by mass or less. The suitable manufacturing method of the copper powder which satisfies the said copper oxidation rate is mentioned later.
  • the peak intensities P 0 , P 1 and P 2 described above have a ratio of P 2 : (P 0 + P 1 ) of 15:85 to 50:50, particularly 23:77 to 47:53, especially 29:71. It is also preferable from the viewpoint of increasing the oxidation resistance of the copper powder to be 41:59.
  • the measuring method of the copper oxidation rate of the copper particles by XPS is as follows.
  • Quantum 2000 manufactured by ULVAC-PHI Co., Ltd. can be used.
  • X-ray source Al—K ⁇ ray (1486.8 eV) can be used.
  • the condition of the X-ray source can be 17 kV ⁇ 0.023 A, for example.
  • the charge correction can be performed with the SiO 2 binding energy of 103.2 eV.
  • the beam diameter was 200 microns (40 W), and measurement was performed in a range of about 300 ⁇ 900 microns.
  • the peak intensities P 0 , P 1 and P 2 described above are in the range of 934.0 eV or more and 936.0 eV or less for Cu (II), and 930.0 eV or more and 933.5 eV or less for Cu (0) and Cu (I). It is calculated from the highest count number (c / s) in the range. These can be measured by a single copper particle, and can also be measured by a mixture with a binder component of a conductive composition. In that case, what is necessary is just to wash
  • the electrode member is a neutral organic solvent (ether, ketone, lactone, aromatic
  • ether, ketone, lactone aromatic
  • the copper powder of the present invention is characterized by a low oxygen content in addition to the surface oxidation state of the copper particles as described above.
  • the copper powder of the present invention preferably has an oxygen content of 0.15% by mass or more and 1.2% by mass or less, and preferably 0.4% by mass or more and 1.0% by mass or less. Further preferred.
  • a conductive composition is prepared using the copper powder of the present invention having an oxygen content within this range, and a conductor is formed from the conductive composition, the conductor is a dense one with few voids in the fired film. Become.
  • the conductive composition using the copper powder of the present invention in which the oxygen content is in this range has a high affinity with the oxygen-containing insulating material and tends to have high adhesion.
  • the oxygen-containing insulator examples include oxide ceramics.
  • oxide ceramics include oxide ceramics of single metal species such as alumina, zirconia, titania, ferrite, magnesia, silica, and mixtures thereof, and composite metal oxide ceramics such as barium titanate and strontium titanate. Is mentioned.
  • other oxygen-containing insulators include resins in which oxygen is included in the structure.
  • oxygen-containing resin examples include epoxy resin, cyanate resin, bismaleimide triazine resin (BT resin), polyphenylene ether resin, phenol resin, polyimide resin and polyamide resin, unsaturated polyester resin, liquid crystal polymer, polyethylene terephthalate resin, polyethylene naphthalene.
  • An insulating resin such as a resin may be used.
  • the resin contains filler particles made of various oxides such as silica and alumina, the resin has good adhesion to the conductive composition using the copper powder of the present invention.
  • the oxygen content in the copper powder of the present invention is measured by the following method.
  • an oxygen / nitrogen analyzer EMGA-620 manufactured by Horiba, Ltd. can be used as an apparatus. After weighing 0.1 g of copper powder and putting it in a nickel capsule, the oxygen content can be determined by burning it in a graphite crucible.
  • the copper powder of the present invention has a volume cumulative particle size D 50 at a cumulative volume of 50% by volume measured by a laser diffraction / scattering particle size distribution measurement method of 0.3 ⁇ m or more and 10 ⁇ m or less, particularly 1.0 ⁇ m or more and 5.5 ⁇ m or less. preferable.
  • a volume cumulative particle size D 50 at a cumulative volume of 50% by volume measured by a laser diffraction / scattering particle size distribution measurement method of 0.3 ⁇ m or more and 10 ⁇ m or less, particularly 1.0 ⁇ m or more and 5.5 ⁇ m or less. preferable.
  • the particle size of the copper particles constituting the copper powder is reduced to this level, the copper particles are easily oxidized due to an increase in the specific surface area.
  • the copper powder of the present invention the copper on the surface of the copper particles As a result, the progress of oxidation due to changes over time can be prevented.
  • the volume cumulative particle diameter D 50 of the above can be carried out, for example, by the following method.
  • 0.1 g of a measurement sample is mixed with 100 ml of a 20 mg / L aqueous solution of sodium hexametaphosphate and dispersed with an ultrasonic homogenizer (US-300T manufactured by Nippon Seiki Seisakusho) for 10 minutes. Thereafter, the particle size distribution is measured using a laser diffraction / scattering particle size distribution measuring apparatus, for example, Microtrack MT-3000 manufactured by Nikkiso Co., Ltd.
  • the copper powder of the present invention may be used after being sintered, or may be used in the form of a powder that is not sintered.
  • the copper powder preferably has a shrinkage start temperature of 480 ° C. or higher and 620 ° C. or lower. In particular, it is preferably 500 ° C. or higher and 580 ° C. or lower.
  • a conductive composition is prepared using the copper powder of the present invention having a shrinkage start temperature in this range, and a conductor is formed from the conductive composition, a “sink” of the fired film due to low temperature shrinkage, or conversely, insufficient firing. Thus, a fired film with less “necking failure” can be formed.
  • the shrinkage start temperature can be measured by a thermomechanical analyzer (TMA).
  • TMA thermomechanical analyzer
  • EXSTAR60006TMA / SS6200 manufactured by Seiko Instruments Inc. can be used as the measuring device.
  • a sample for measuring the shrinkage start temperature for example, a cylindrical molded body is used in which 0.2 g of copper powder weighed in advance is placed in an aluminum case with an inner diameter of 3.8 mm ⁇ and molded with a load of 4835N.
  • This cylindrical molded body was mounted on a thermomechanical analyzer (TMA), and the thermal expansion coefficient (%) in the vertical direction when the temperature was raised at a rate of 10 ° C./min under a load of 98 mN and nitrogen was monitored. Measure the temperature (° C) that first changed from positive to negative. That temperature can be defined as the shrinkage onset temperature.
  • TMA thermomechanical analyzer
  • the copper particles constituting the copper powder of the present invention are not particularly limited in shape, and can be used in various shapes such as a spherical shape, a flake shape, a plate shape, and a dendritic shape. What shape copper particles are used may be appropriately determined according to the specific application of the copper powder of the present invention.
  • the shape of the copper particles generally depends on the manufacturing method. Spherical copper particles can be produced, for example, by an atomization method or a wet reduction method.
  • the flaky particles can be produced, for example, by mechanically plastically deforming spherical particles.
  • the plate-like particles can be produced, for example, by a wet reduction method.
  • Dendritic copper particles can be produced, for example, by an electrolytic method.
  • the copper powder of the present invention may be a mixture of copper particles having various shapes.
  • the copper particle which comprises the copper powder of this invention exhibits each said shape
  • the copper powder of this invention is observed by electron microscope observation (for example, 1000 time)
  • grains which exhibit said each shape Meaning that the number accounts for 80% or more.
  • the copper powder of this invention is suitably manufactured by oxidizing the raw material copper powder manufactured by various methods on a suitable condition in a predetermined atmosphere.
  • the method for producing the raw material copper powder there are no particular restrictions on the method for producing the raw material copper powder, but when producing copper powder composed of spherical copper particles, for example, it is preferable to use the atomizing method, which produces fine copper powder having an average particle size of 3 ⁇ m or less. In this case, a wet method is preferable.
  • a gas atomizing method or a water atomizing method can be preferably employed.
  • a gas atomizing method In order to make the particle shape uniform, it is preferable to employ a gas atomizing method.
  • a water atomizing method when the particles are miniaturized.
  • the high pressure atomization method is particularly preferable because the particles can be produced finely and uniformly.
  • the high-pressure atomizing method is a method of atomizing at a water pressure of about 50 MPa to 150 MPa in the water atomizing method.
  • atomization is performed at a gas pressure of about 0.5 MPa to 3 MPa.
  • a reduction precipitation method in which a reducing agent is added to a slurry obtained by adding an alkaline aqueous solution to a copper salt aqueous solution can be employed.
  • first reducing agents such as reducing sugar, hypophosphorous acid and sodium sulfite are added to the slurry to prepare a cuprous oxide slurry, and then hydrazine such as hydrated hydrazine and hydrazine sulfate.
  • a two-step reduction method in which a strongly basic reducing agent such as a compound or sodium borohydride is added is preferred.
  • the raw material copper powder may be classified before being subjected to oxidation treatment. This classification can be easily carried out by separating coarse powder and fine powder from the obtained raw material copper powder using an appropriate classification apparatus so that the target particle size becomes the center. Classification, the value of D 50 of the raw material copper powder, is preferably performed such that the ranges set forth above.
  • Suitable oxidation conditions include, for example, conditions for standing in an air atmosphere having a relative humidity of 40% RH to 80% RH and a temperature of 60 ° C. to 120 ° C. as industrial treatment conditions.
  • the treatment time is on condition that the atmospheric conditions are within the above range. It is preferably 20 minutes or longer and 650 minutes or shorter, more preferably 30 minutes or longer and 600 minutes or shorter, and even more preferably 30 minutes or longer and 180 minutes or shorter.
  • the relative humidity is low, the oxidation rate tends to be slow.
  • the temperature may be set higher.
  • the treatment temperature is preferably 70 ° C. or more and 130 ° C. or less.
  • the treatment temperature is 60 ° C. or more and 90 ° C. or less. Is preferred.
  • the copper powder to be oxidized for example, dry powder having a low moisture content can be used.
  • the moisture content can be set to 0.1% by mass or less, for example.
  • the oxidation rate tends to be slow, but the oxidation rate can be increased by adding moisture to the copper powder.
  • the oxidation treatment of the copper powder can be performed in a state where moisture is added in the range of 1% by mass to 5% by mass with respect to the mass of the dry copper powder.
  • the target copper powder can be successfully produced.
  • the copper powder thus obtained is preferably sealed in a non-moisture permeable material container and stored at a temperature of room temperature (25 ° C.) or lower for the purpose of maintaining the oxidized state of the copper particle surface. .
  • the copper powder of the present invention has excellent conductive properties, high oxidation resistance, and good compatibility with glass frit, a conductive resin composition such as a conductive paste or a conductive adhesive, or a conductive paint
  • a conductive resin composition such as a conductive paste or a conductive adhesive, or a conductive paint
  • it can be suitably used as a main constituent material of various conductive materials.
  • the copper powder of the present invention may be mixed with a binder and a solvent. By doing so, a high-temperature fired conductive paste can be obtained. Or the copper powder of this invention can also be mixed with a binder and a solvent, and also a hardening
  • binder examples include, but are not limited to, a liquid epoxy resin, an acrylic resin, a phenol resin, and an unsaturated polyester resin.
  • solvent examples include terpineol, ethyl carbitol, carbitol acetate, butyl cellosolve, butyl carbitol acetate and the like.
  • curing agent examples include 2-ethyl 4-methylimidazole.
  • the curing accelerator include tertiary amines, tertiary amine salts, imidazoles, phosphines, phosphonium salts and the like.
  • the conductive paste when used for an oxide ceramic electronic component that needs to be sintered, it is preferable to further mix a glass frit in the conductive paste for the purpose of improving adhesion to the oxide ceramic.
  • a glass frit for example, silica as an essential component, alumina, boron oxide, calcium carbonate, titanium oxide, zinc oxide, bismuth oxide, vanadium oxide, phosphoric acid, antimony oxide, iron oxide, tellurium oxide, tin oxide, cerium oxide, Examples thereof include a mixture obtained by heating, melting and pulverizing a mixture to which at least one oxide selected from the group consisting of lanthanum oxide and tin oxide is added.
  • the conductive paste containing the copper powder of the present invention can be suitably used, for example, for forming a conductor circuit by screen printing or for electrical contact members of various electronic components.
  • electronic components for example, internal electrodes of multilayer ceramic capacitors, chip components such as inductors and resistors, single plate capacitor electrodes, tantalum capacitor electrodes, resin multilayer substrates, low temperature co-fired ceramic (LTCC) multilayer substrates, antenna switch modules, PA modules and high frequency active filters And the like.
  • insulating materials for ceramic electronic parts include oxide ceramics such as alumina, zirconia, titania, ferrite, magnesia, and silica, and ceramic composite oxides such as barium titanate and strontium titanate.
  • Electrodes for printed wiring boards such as flexible printed circuit boards (FPCs) and build-up multilayer wiring boards for electronic components that use resin as an insulating material
  • electromagnetic shielding films for PDP front and back plates PDP color filters, and crystals
  • conductive adhesive EMI shield
  • RF-ID membrane switch
  • PC keyboard anisotropic conductive film
  • ACF / ACP anisotropic conductive film
  • the resin When using a resin as the insulating material, specific examples of the resin include epoxy resin, cyanate resin, bismaleimide triazine resin (BT resin), polyphenylene ether resin, phenol resin, polyimide resin, polyamide resin, unsaturated polyester resin, Examples thereof include an insulating resin such as a liquid crystal polymer, a polyethylene terephthalate resin, and a polyethylene naphthalene resin.
  • the resin may also contain filler particles made of various oxide inorganic particles such as silica and alumina.
  • the obtained copper powder was classified by a classifier (“Turbo Classifier (trade name) TC-25 (model number)” manufactured by Nissin Engineering Co., Ltd.), and the classified copper powder was used as the raw material copper powder A.
  • the raw material copper powder A was a spherical dry powder, and the D 50 and oxygen content ratios were as shown in Table 1 below.
  • the raw material copper powder B was obtained in the same manner as the raw material copper powder A, except that the classification point of the classifier was changed.
  • the raw material copper powder B was a spherical dry powder, and the D 50 and oxygen content ratios were as shown in Table 1 below.
  • the raw material copper powder C was obtained in the same manner as the raw material copper powder A, except that the classification point of the classifier was changed.
  • the raw material copper powder C was a spherical dry powder, and the D 50 and oxygen content ratios were as shown in Table 1 below.
  • Example 1 1000 g of the raw material copper powder A was left in a constant temperature and humidity chamber adjusted to 80 ° C. and 80% RH for 30 minutes and subjected to an oxidation treatment in an air atmosphere. Thus, the target copper powder was obtained.
  • Example 2 The target copper powder was obtained in the same manner as in Example 1 except that the raw material copper powder shown in the same table was oxidized under the conditions shown in Table 2 below.
  • Examples 11 and 12 The same as Example 1 except that 3% by mass of water is added to the mass of the raw material copper powder shown in Table 2 and the raw copper powder is moistened under the conditions shown in the same table. Thus, the intended copper powder was obtained.
  • Example 13 The same as Example 1 except that 1% by mass of water is added to the mass of the raw material copper powder shown in Table 2 and the raw copper powder is moistened under the conditions shown in the same table. Thus, the intended copper powder was obtained.
  • Example 5 The target copper powder was obtained in the same manner as in Example 1 except that the raw material copper powder shown in the same table was oxidized under the conditions shown in Table 2 below.
  • Example 8 Example 1 except that 3% by mass of water is added to the mass of the raw material copper powder shown in Table 2 below and the raw copper powder is moistened under the conditions shown in the same table. In the same manner as above, the intended copper powder was obtained.
  • a conductive paste (1) To the copper powder obtained in Examples and Comparative Examples, terpineol and acrylic resin were added and mixed to prepare a conductive paste (1).
  • the proportion of copper powder in the conductive paste (1) was 70% by mass, the proportion of terpineol was 25% by mass, and the proportion of acrylic resin was 5% by mass.
  • This conductive paste (1) was applied on an alumina substrate with a film thickness of 50 ⁇ m to form a coating film.
  • This coating film was baked at 845 ° C. for 20 minutes in a nitrogen atmosphere to obtain a baked film.
  • the surface of the obtained fired film was magnified with a scanning electron microscope (1000 times), and images of 10 fields of view were taken.
  • the void area ratio is a value obtained by calculating the area of voids (5 ⁇ m or more) included in one visual field by image analysis and arithmetically averaging the values of the ten visual fields. If the void area is too large, the denseness is insufficient. Conversely, if the void area is too small, the denseness is too high and adversely affects the glass distribution uniformity described later. The quality of the denseness was evaluated in the following three stages.
  • ⁇ The void area ratio is 1% or more and less than 3%, or more than 7% and 10% or less.
  • X Void area ratio is less than 1% or more than 10%.
  • Adhesion of fired film II The adhesiveness of the fired film was evaluated from another viewpoint. Specifically, after the fired film is immersed in the ultrasonic cleaner for 30 seconds together with the substrate, the surface of the fired film is observed with a scanning electron microscope (1000 times), and the fired film in an observation field of about 100 ⁇ m square is observed. The quality of adhesion was evaluated in the following three stages. A: No peeling of the fired film is observed. ⁇ : 70% or more of the fired film area is in close contact. X: The area of the fired film in close contact is less than 30%.
  • the surface of the fired film was subjected to EDX analysis on an image obtained at a field of view of about 100 ⁇ m square and 1000 times, and the glass distribution uniformity was evaluated from the amount of Si derived from the glass frit.
  • the evaluation criteria are as follows.
  • the amount of Si is an amount defined by Si ⁇ 100 / (Si + Cu).
  • Si and Cu represent peak intensities of Si and Cu in EDX analysis.
  • ⁇ Si amount is 0.5% or more and less than 1%, or more than 10% and 20% or less
  • X The amount of Si is less than 0.5% or more than 20%.
  • A Two or more items among the denseness I, the adhesion II, and the uniformity evaluation are A.
  • ⁇ One item or more among the denseness I, the adhesiveness II, and the uniformity evaluation is ⁇ .
  • X Among the denseness I, the adhesiveness II and the uniformity evaluation, there is x in one or more items.
  • the copper powder obtained in each example has a higher oxidation start temperature and superior oxidation resistance compared to the copper powder of the comparative example.
  • the fired film manufactured using the copper powder obtained in each example as a raw material has a higher film density than the fired film manufactured using the copper powder of the comparative example as a raw material, and copper powder and glass It turns out that familiarity with is good.
  • copper powder excellent in shrinkage temperature control is provided. Since this copper powder has good compatibility with the glass frit at the time of firing, a fired film having excellent denseness can be obtained by using this copper powder. Moreover, when this copper powder is made into a conductive composition, it is possible to obtain an electronic component having a high affinity with an oxygen-containing insulating material and a high adhesion reliability.

Abstract

The copper powder according to the present invention has an X-ray photoelectron spectroscopy (XPS) spectrum, which is obtained by measuring the surface of copper particles using an X-ray photoelectron spectroscope, in which the ratio P2/(P1+P0), which is the ratio of the peak intensity P1 of Cu(I) and the peak intensity P0 of Cu(0) to the peak intensity P2 of Cu(II), is 0.15–1. The proportional content of oxygen is preferably 0.15–1.2 mass%. The volume accumulation particle diameter D50 at an accumulation volume of 50 vol.%, as measured by the light scattering particle sizing technique, is preferably 0.3–10 µm.

Description

銅粉Copper powder
　本発明は銅粉に関する。 The present invention relates to copper powder.
　銅粉は、導電性ペースト等の導電性組成物の原料として好適に用いられている。導電性組成物は、バインダ樹脂及び有機溶媒を含むビヒクル中に銅粉を分散させてなるものである。導電性組成物は、例えば電気回路の形成や、セラミックコンデンサの外部電極の形成などに用いられている。 Copper powder is suitably used as a raw material for conductive compositions such as conductive paste. The conductive composition is obtained by dispersing copper powder in a vehicle containing a binder resin and an organic solvent. The conductive composition is used, for example, for forming an electric circuit or forming an external electrode of a ceramic capacitor.
　近年、電気回路などにおいてファインピッチ化が進むのに伴い、導電性組成物用の銅粉も微粉化され、銅粉の比表面積が大きくなってきている。そのことに起因して、銅粉は一層酸化しやすい状態となってきている。そこで、銅粉の酸化を防止するための技術が種々提案されている。例えば、アトマイズ法で銅粉を製造するときに、銅粉に対して０．０１～０．１重量％のホウ素を添加することで、酸化膜の生成を少なくする技術が提案されている（特許文献１参照）。特許文献２には、Ａｌ、Ｍｇ、Ｇｅ及びＧａのいずれかを含有する銅粉が記載されている。 In recent years, with the progress of fine pitch in electric circuits and the like, copper powder for conductive compositions has also been made finer, and the specific surface area of copper powder has increased. As a result, the copper powder is more easily oxidized. Therefore, various techniques for preventing oxidation of copper powder have been proposed. For example, when producing copper powder by the atomizing method, a technique has been proposed in which 0.01 to 0.1% by weight of boron is added to the copper powder to reduce the formation of an oxide film (patent) Reference 1). Patent Document 2 describes a copper powder containing any one of Al, Mg, Ge, and Ga.
特開２００８－９５１６９号公報JP 2008-95169 A 特開２０１１－６７３９号公報JP 2011-6739 A
　上述の特許文献１及び２に記載の銅粉では、銅以外の元素を銅粉中に含有させることで銅の酸化を防止している。そのため、該銅粉を含む導電性組成物から形成された導体中には、銅粉中に含まれていた元素が残存することになる。導体の使用態様や使用部位によっては、該元素が接合信頼性や導通特性に対して悪影響を及ぼすことがあるので、銅粉の使用場面が限られる場合がある。 In the copper powder described in Patent Documents 1 and 2, the copper powder is prevented from being oxidized by containing an element other than copper in the copper powder. Therefore, the element contained in the copper powder remains in the conductor formed from the conductive composition containing the copper powder. Depending on how the conductor is used and where it is used, the use of copper powder may be limited because the element may adversely affect the bonding reliability and conduction characteristics.
　したがって本発明の課題は銅粉の改良にあり、更に詳しくは異種元素を用いなくても表面の安定性に優れ、導電性組成物の緻密性や酸素含有絶縁材料との密着性、分布の均一性に優れた銅粉を提供することにある。 Therefore, the object of the present invention is to improve copper powder. More specifically, the surface stability is excellent without using different elements, the denseness of the conductive composition, the adhesion with the oxygen-containing insulating material, and the uniform distribution. The object is to provide copper powder with excellent properties.
　本発明は、Ｘ線光電子分光装置（ＸＰＳ）を用いて表面を測定して得られるＸ線光電子分光スペクトルにおいて、Ｃｕ（II）のピーク強度Ｐ２に対する、Ｃｕ（I）のピーク強度Ｐ１及びＣｕ（０）のピーク強度Ｐ０の比率であるＰ２／（Ｐ0＋Ｐ1）の値が０．１５以上１以下である、銅粉を提供するものである。 In the X-ray photoelectron spectrum obtained by measuring the surface using an X-ray photoelectron spectrometer (XPS), the present invention provides a peak intensity P 1 of Cu (I) with respect to a peak intensity P 2 of Cu (II) and A copper powder having a value of P 2 / (P 0 + P 1 ), which is a ratio of the peak intensity P 0 of Cu (0), is 0.15 or more and 1 or less.
　また本発明は、前記の銅粉の好適な製造方法として、
　乾燥した原料銅粉を、相対湿度が４０％ＲＨ以上８０％ＲＨ以下で、かつ温度が２０℃以上１２０℃以下の大気雰囲気下に、２０分以上６５０分以下静置して酸化処理を行う銅粉の製造方法を提供するものである。 Moreover, this invention is as a suitable manufacturing method of the said copper powder,
Copper which performs oxidation treatment by leaving the dried raw material copper powder to stand for 20 minutes or more and 650 minutes or less in an air atmosphere having a relative humidity of 40% RH to 80% RH and a temperature of 20 ° C to 120 ° C. A method for producing a powder is provided.
　以下本発明を、その好ましい実施形態に基づき説明する。本発明の銅粉は、銅粒子の集合体からなるものである。本発明の銅粉は、銅粒子のみから実質的になるが、不可避不純物を含有することは許容される。また、必要に応じ、本発明の銅粉に、それ以外の粉体等を含有させてもよい。 Hereinafter, the present invention will be described based on preferred embodiments thereof. The copper powder of the present invention is composed of an aggregate of copper particles. The copper powder of the present invention consists essentially of copper particles, but it is allowed to contain inevitable impurities. Moreover, you may make the copper powder of this invention contain other powders etc. as needed.
　本発明の銅粉は、銅粒子の表面に存在する銅の酸化状態に特徴の一つを有する。詳細には、本発明の銅粉を構成する銅粒子は、銅粒子の表面における金属銅（つまりＣｕ（０））、一価の銅（つまりＣｕ（I））及び二価の銅（つまりＣｕ（II））の存在比率が特異なものとなっている。これら各種価数の銅の存在比率はＸ線光電子分光装置（ＸＰＳ）を用いて測定することができる。ＸＰＳ測定によれば、各種元素のＸ線光電子分光スペクトルが得られる。ＸＰＳでは、銅粒子の表面から約十ｎｍまでの深さの元素成分について定量分析を行うことができる。ＸＰＳによって本発明の銅粉を構成する銅粒子の表面状態を測定して得られたＸ線光電子分光スペクトルにおいては、Ｃｕ（II）のピーク強度Ｐ２に対する、Ｃｕ（I）のピーク強度Ｐ１及びＣｕ（０）のピーク強度Ｐ０の比率であるＰ２／（Ｐ0＋Ｐ1）の値が、好ましくは０．１５以上１以下であり、更に好ましくは０．３以上０．９以下であり、一層好ましくは０．４以上０．７以下である。以下、Ｐ２／（Ｐ１＋Ｐ０）の値のことを「銅酸化率」と言う。なお、ピーク強度とは、ピークの高さのことである。 The copper powder of this invention has one of the characteristics in the oxidation state of the copper which exists in the surface of a copper particle. Specifically, the copper particles constituting the copper powder of the present invention are metallic copper (that is, Cu (0)), monovalent copper (that is, Cu (I)), and divalent copper (that is, Cu) on the surface of the copper particles. The ratio of (II)) is unique. The abundance ratio of copper having various valences can be measured using an X-ray photoelectron spectrometer (XPS). According to XPS measurement, X-ray photoelectron spectroscopy spectra of various elements are obtained. In XPS, quantitative analysis can be performed on elemental components at a depth of about 10 nm from the surface of the copper particles. In the X-ray photoelectron spectrum obtained by measuring the surface state of the copper particles constituting the copper powder of the present invention by XPS, the peak intensity P 1 of Cu (I) with respect to the peak intensity P 2 of Cu (II). And the ratio of P 2 / (P 0 + P 1 ), which is the ratio of the peak intensity P 0 of Cu (0), is preferably 0.15 or more and 1 or less, more preferably 0.3 or more and 0.9 or less. Yes, more preferably 0.4 or more and 0.7 or less. Hereinafter, the value of P 2 / (P 1 + P 0 ) is referred to as “copper oxidation rate”. The peak intensity is the height of the peak.
　Ｘ線光電子分光スペクトルにおいて、Ｃｕ（II）のピークは、主としてＣｕＯ及びＣｕ（ＯＨ）２に由来し、９３４．０ｅＶ以上９３６．０ｅＶ以下の範囲に観察される。これらのピークは同一位置に観察されるので、両者を区別することはできない。Ｃｕ（I）のピークは、主としてＣｕ２Ｏに由来する。またＣｕ（０）のピークは金属銅に由来する。Ｃｕ（I）のピーク及びＣｕ（０）のピークは９３０．０ｅＶ以上９３３．５ｅＶ以下の範囲の同一位置に観察されるので、両者を分離することはできない。そこで本発明では、銅酸化率の定義を上述のとおりとする。 In the X-ray photoelectron spectroscopy spectrum, the peak of Cu (II) is mainly derived from CuO and Cu (OH) 2 and is observed in the range of 934.0 eV or more and 936.0 eV or less. Since these peaks are observed at the same position, they cannot be distinguished from each other. The peak of Cu (I) is mainly derived from Cu 2 O. The Cu (0) peak is derived from metallic copper. Since the peak of Cu (I) and the peak of Cu (0) are observed at the same position in the range of 930.0 eV to 933.5 eV, the two cannot be separated. Therefore, in the present invention, the definition of the copper oxidation rate is as described above.
　銅酸化率が上述の範囲内である銅粒子からなる銅粉は、銅粒子表面に存在するＣｕ（I）及びＣｕ（０）の合計量よりも、Ｃｕ（II）の量の方が小さいか、又は同程度である。Ｃｕ（II）の量を適切に設定することで、本発明の銅粉を含む導電性組成物から得られる導体を緻密な構造にすることができる。また、導電性組成物と酸素含有絶縁材料との親和性が高いために、電子部品の基材や誘電材料との密着性が高くなり、密着信頼性の高い電子部品を得ることができる。したがって、本発明の銅粉を用いて、電子部品用電極を好適に製造することができる。更に、導電性組成物中にガラスフリットが含まれている場合には、導電性組成物をセラミックス電子部品の電極として用いたときに、銅粒子とセラミックス材料とガラスフリットとのなじみが良好になるので、焼結が必要なセラミックス電子部品用の導電性組成物として使った場合に、焼結中にガラス成分が偏析することが効果的に防止される。これによっても、導体を緻密な構造にすることができる。また、本発明の銅粉は、銅以外の異種元素を実質的に含まないので、使用場面の制約が少ないという点でも利点を有する。「異種元素を実質的に含まない」とは、銅粉を元素分析したときに、銅及び酸素以外の異種元素の含有割合の合計が０．１質量％以下であることを言う。前記の銅酸化率を満足する銅粉の好適な製造方法については後述する。 Is the amount of Cu (II) smaller than the total amount of Cu (I) and Cu (0) present on the copper particle surface of the copper powder composed of copper particles having a copper oxidation rate within the above range? Or similar. By setting the amount of Cu (II) appropriately, the conductor obtained from the conductive composition containing the copper powder of the present invention can be made into a dense structure. In addition, since the affinity between the conductive composition and the oxygen-containing insulating material is high, the adhesion of the electronic component to the base material or the dielectric material is increased, and an electronic component with high adhesion reliability can be obtained. Therefore, the electrode for electronic components can be suitably manufactured using the copper powder of the present invention. Furthermore, when the conductive composition contains glass frit, the familiarity between the copper particles, the ceramic material, and the glass frit is improved when the conductive composition is used as an electrode of a ceramic electronic component. Therefore, when used as a conductive composition for ceramic electronic components that require sintering, it is possible to effectively prevent segregation of glass components during sintering. This also allows the conductor to have a dense structure. Moreover, since the copper powder of this invention does not contain dissimilar elements other than copper substantially, it has an advantage also in the point that there are few restrictions of a use scene. “Substantially free of different elements” means that when the copper powder is subjected to elemental analysis, the total content of different elements other than copper and oxygen is 0.1% by mass or less. The suitable manufacturing method of the copper powder which satisfies the said copper oxidation rate is mentioned later.
　また、上述のピーク強度Ｐ０、Ｐ１及びＰ２は、Ｐ２：（Ｐ０＋Ｐ１）の比率が、１５：８５～５０：５０、特に２３：７７～４７：５３、とりわけ２９：７１～４１：５９であることも、銅粉の耐酸化性を高める観点から好ましい。 The peak intensities P 0 , P 1 and P 2 described above have a ratio of P 2 : (P 0 + P 1 ) of 15:85 to 50:50, particularly 23:77 to 47:53, especially 29:71. It is also preferable from the viewpoint of increasing the oxidation resistance of the copper powder to be 41:59.
　ＸＰＳによる銅粒子の銅酸化率の測定方法は以下のとおりである。装置としては、例えばアルバック・ファイ株式会社社製のＱｕａｎｔｕｍ２０００を用いることができる。Ｘ線源としては、Ａｌ－Ｋα線（１４８６． ８ｅＶ）を用いることができる。Ｘ線源の条件は、例えば１７ｋＶ×０．０２３Ａとすることができる。帯電補正は、ＳｉＯ２の結合エネルギーを１０３．２ｅＶとして行うことができる。またビーム径は２００ミクロン（４０Ｗ）とし、約３００×９００ミクロンの範囲で測定を行った。上述のピーク強度Ｐ０、Ｐ１及びＰ２は、Ｃｕ（II）については９３４．０ｅＶ以上９３６．０ｅＶ以下の範囲、Ｃｕ（０）及びＣｕ（Ｉ）については９３０．０ｅＶ以上９３３．５ｅＶ以下の範囲で最も高いカウント数（ｃ／ｓ）から算出する。これらは、銅粒子単体で測定が可能なほか、導電性組成物のバインダ成分との混合体であっても測定が可能である。その場合には、テルピネオールなどのアルコール有機溶剤で洗浄し、銅粒子を露出させた状態で測定すればよい。また、後述する電子部品用の電極を形成した場合において、銅粒子が焼結、溶融、溶着されていない電極においては、電極部材を中性の有機である溶剤（エーテル、ケトン、ラクトン、芳香族炭化水素、テルピネオール、カルビトールアセテート等）の混合溶液中で高温高圧で煮沸し樹脂を膨潤させることにより、表面の露出した銅粒子単体を取出し、ろ過し風乾させたもので測定することが可能である。 The measuring method of the copper oxidation rate of the copper particles by XPS is as follows. As the apparatus, for example, Quantum 2000 manufactured by ULVAC-PHI Co., Ltd. can be used. As the X-ray source, Al—Kα ray (1486.8 eV) can be used. The condition of the X-ray source can be 17 kV × 0.023 A, for example. The charge correction can be performed with the SiO 2 binding energy of 103.2 eV. The beam diameter was 200 microns (40 W), and measurement was performed in a range of about 300 × 900 microns. The peak intensities P 0 , P 1 and P 2 described above are in the range of 934.0 eV or more and 936.0 eV or less for Cu (II), and 930.0 eV or more and 933.5 eV or less for Cu (0) and Cu (I). It is calculated from the highest count number (c / s) in the range. These can be measured by a single copper particle, and can also be measured by a mixture with a binder component of a conductive composition. In that case, what is necessary is just to wash | clean with alcohol organic solvents, such as terpineol, and to measure in the state which exposed the copper particle. In addition, when an electrode for an electronic component to be described later is formed, in an electrode in which copper particles are not sintered, melted, or welded, the electrode member is a neutral organic solvent (ether, ketone, lactone, aromatic By boiling the resin in a mixed solution of hydrocarbons, terpineol, carbitol acetate, etc. at high temperature and high pressure to swell the resin, the exposed copper particles can be taken out, filtered and air-dried. is there.
　本発明の銅粉は、銅粒子の表面酸化状態が上述のとおりであることに加えて、酸素の含有割合が低いことも特徴の一つである。詳細には、本発明の銅粉は、酸素の含有割合が０．１５質量％以上１．２質量％以下であることが好ましく、０．４質量％以上１．０質量％以下であることが更に好ましい。酸素の含有割合がこの範囲にある本発明の銅粉を用いて導電性組成物を調製し、該導電性組成物から導体を形成すると、該導体は焼成膜中にボイドが少ない緻密なものとなる。また、酸素の含有割合がこの範囲にある本発明の銅粉を用いた導電性組成物は、酸素含有絶縁材料との親和性が高く、密着性が高くなりやすい。また、導電性組成物中にガラスフリットが含まれている場合には、銅粒子とガラスフリットとのなじみが良好になり、導体中でのガラスの存在が均一になりやすい。前記の酸素含有絶縁体の例としては、酸化物セラミックスが挙げられる。酸化物セラミックスとしては、例えばアルミナ、ジルコニア、チタニア、フェライト、マグネシア、シリカ等の単一金属種の酸化物セラミックやこれらの混合物の他、チタン酸バリウムやチタン酸ストロンチウム等の複合金属酸化物セラミック等が挙げられる。その他の酸素含有絶縁体の例としては、酸素が構造中に含まれる樹脂が挙げられる。酸素含有樹脂としては、例えばエポキシ樹脂、シアネート樹脂、ビスマレイミドトリアジン樹脂（ＢＴ樹脂）、ポリフェニレンエーテル樹脂、フェノール樹脂、ポリイミド樹脂やポリアミド樹脂、不飽和ポリエステル樹脂、液晶ポリマー、ポリエチレンテレフタラート樹脂、ポリエチレンナフタレン樹脂等の絶縁樹脂が挙げられる。その他、樹脂にシリカやアルミナ等の各種酸化物からなるフィラー粒子等が含有される場合、該樹脂は、本発明の銅粉を用いた導電性組成物との接着性が良好である。 The copper powder of the present invention is characterized by a low oxygen content in addition to the surface oxidation state of the copper particles as described above. Specifically, the copper powder of the present invention preferably has an oxygen content of 0.15% by mass or more and 1.2% by mass or less, and preferably 0.4% by mass or more and 1.0% by mass or less. Further preferred. When a conductive composition is prepared using the copper powder of the present invention having an oxygen content within this range, and a conductor is formed from the conductive composition, the conductor is a dense one with few voids in the fired film. Become. In addition, the conductive composition using the copper powder of the present invention in which the oxygen content is in this range has a high affinity with the oxygen-containing insulating material and tends to have high adhesion. Further, when glass frit is contained in the conductive composition, the familiarity between the copper particles and the glass frit is improved, and the presence of glass in the conductor tends to be uniform. Examples of the oxygen-containing insulator include oxide ceramics. Examples of oxide ceramics include oxide ceramics of single metal species such as alumina, zirconia, titania, ferrite, magnesia, silica, and mixtures thereof, and composite metal oxide ceramics such as barium titanate and strontium titanate. Is mentioned. Examples of other oxygen-containing insulators include resins in which oxygen is included in the structure. Examples of the oxygen-containing resin include epoxy resin, cyanate resin, bismaleimide triazine resin (BT resin), polyphenylene ether resin, phenol resin, polyimide resin and polyamide resin, unsaturated polyester resin, liquid crystal polymer, polyethylene terephthalate resin, polyethylene naphthalene. An insulating resin such as a resin may be used. In addition, when the resin contains filler particles made of various oxides such as silica and alumina, the resin has good adhesion to the conductive composition using the copper powder of the present invention.
　本発明の銅粉における酸素の含有割合は次の方法で測定される。装置として、例えば株式会社堀場製作所社製の酸素・窒素分析装置ＥＭＧＡ－６２０を用いることができる。銅粉０．１ｇを秤量し、ニッケルカプセルに入れた後、黒鉛坩堝内で燃焼させることで、酸素の含有割合を求めることができる。 The oxygen content in the copper powder of the present invention is measured by the following method. As an apparatus, for example, an oxygen / nitrogen analyzer EMGA-620 manufactured by Horiba, Ltd. can be used. After weighing 0.1 g of copper powder and putting it in a nickel capsule, the oxygen content can be determined by burning it in a graphite crucible.
　本発明の銅粉は、レーザー回折散乱式粒度分布測定法による累積体積５０容量％における体積累積粒径Ｄ50が、０．３μｍ以上１０μｍ以下、特に１．０μｍ以上５．５μｍ以下であることが好ましい。銅粉を構成する銅粒子の粒径がこの程度にまで小さくなると、比表面積が増大することに起因して銅粒子は酸化されやすくなるが、本発明の銅粉では、銅粒子の表面における銅の酸化状態が適切に制御されていることに起因して、経時変化による酸化の進行を防ぐことができる。 The copper powder of the present invention has a volume cumulative particle size D 50 at a cumulative volume of 50% by volume measured by a laser diffraction / scattering particle size distribution measurement method of 0.3 μm or more and 10 μm or less, particularly 1.0 μm or more and 5.5 μm or less. preferable. When the particle size of the copper particles constituting the copper powder is reduced to this level, the copper particles are easily oxidized due to an increase in the specific surface area. However, in the copper powder of the present invention, the copper on the surface of the copper particles As a result, the progress of oxidation due to changes over time can be prevented.
　上述の体積累積粒径Ｄ５０の測定は、例えば以下の方法で行うことができる。０．１ｇの測定試料を、ヘキサメタリン酸ナトリウムの２０ｍｇ／Ｌ水溶液１００ｍｌと混合し、超音波ホモジナイザ（日本精機製作所製　ＵＳ－３００Ｔ）で１０分間分散させる。その後、レーザー回折散乱式粒度分布測定装置、例えば日機装社製マイクロトラックＭＴ－３０００を用いて粒度分布を測定する。 The volume cumulative particle diameter D 50 of the above can be carried out, for example, by the following method. 0.1 g of a measurement sample is mixed with 100 ml of a 20 mg / L aqueous solution of sodium hexametaphosphate and dispersed with an ultrasonic homogenizer (US-300T manufactured by Nippon Seiki Seisakusho) for 10 minutes. Thereafter, the particle size distribution is measured using a laser diffraction / scattering particle size distribution measuring apparatus, for example, Microtrack MT-3000 manufactured by Nikkiso Co., Ltd.
　本発明の銅粉はこれを焼結させて用いてもよく、あるいは焼結させない粉体の状態で用いてもよい。本発明の銅粉を焼結させて用いる場合には、該銅粉はその収縮開始温度が、４８０℃以上６２０℃以下であることが好ましい。特に５００℃以上５８０℃以下であることが好ましい。収縮開始温度がこの範囲にある本発明の銅粉を用いて導電性組成物を調製し、該導電性組成物から導体を形成すると、低温収縮による焼成膜の「ヒケ」や、逆に焼成不足による「ネッキング不良」の少ない焼成膜が形成できる。その結果、焼成膜はボイドが少ない緻密なものとなる。また、導電性組成物中にガラスフリットが含まれている場合には、銅粒子とガラスフリットとのなじみが良好になり、導体中での軟化したガラスの存在が均一となる焼成膜を得やすい。収縮開始温度は、熱機械分析装置（ＴＭＡ）によって測定することができる。測定装置は、例えばセイコーインスツル社製　ＥＸＳＴＡＲ６０００ ＴＭＡ／ＳＳ６２００を用いることができる。収縮開始温度を測定するための試料としては、例えば予め秤量した銅粉０．２ｇを内径３．８ｍｍφのアルミケースに入れ、４８３５Ｎの荷重をかけて成形した円柱成形体が用いられる。この円柱成形体を熱機械分析装置（ＴＭＡ）に装着し、荷重９８ｍＮ、窒素雰囲気下、速度１０℃／ｍｉｎで昇温したときの縦方向の熱膨張率（％）をモニターし、膨張挙動が正から負へ初めて転じた温度（℃）を測定する。その温度を収縮開始温度と定義することができる。 The copper powder of the present invention may be used after being sintered, or may be used in the form of a powder that is not sintered. When the copper powder of the present invention is sintered and used, the copper powder preferably has a shrinkage start temperature of 480 ° C. or higher and 620 ° C. or lower. In particular, it is preferably 500 ° C. or higher and 580 ° C. or lower. When a conductive composition is prepared using the copper powder of the present invention having a shrinkage start temperature in this range, and a conductor is formed from the conductive composition, a “sink” of the fired film due to low temperature shrinkage, or conversely, insufficient firing. Thus, a fired film with less “necking failure” can be formed. As a result, the fired film is dense with few voids. In addition, when glass frit is contained in the conductive composition, the familiarity between the copper particles and the glass frit is improved, and it is easy to obtain a fired film in which the presence of the softened glass in the conductor is uniform. . The shrinkage start temperature can be measured by a thermomechanical analyzer (TMA). As the measuring device, for example, EXSTAR6000６TMA / SS6200 manufactured by Seiko Instruments Inc. can be used. As a sample for measuring the shrinkage start temperature, for example, a cylindrical molded body is used in which 0.2 g of copper powder weighed in advance is placed in an aluminum case with an inner diameter of 3.8 mmφ and molded with a load of 4835N. This cylindrical molded body was mounted on a thermomechanical analyzer (TMA), and the thermal expansion coefficient (%) in the vertical direction when the temperature was raised at a rate of 10 ° C./min under a load of 98 mN and nitrogen was monitored. Measure the temperature (° C) that first changed from positive to negative. That temperature can be defined as the shrinkage onset temperature.
　本発明の銅粉を構成する銅粒子は、その形状に特に制限はなく、例えば球状、フレーク状、板状、樹枝状など種々の形状で用いることができる。どのような形状の銅粒子を用いるかは、本発明の銅粉の具体的な用途に応じて適切に判断すればよい。銅粒子の形状は一般にその製造方法に依存する。球状の銅粒子は例えばアトマイズ法や湿式還元法で製造することができる。フレーク状の粒子は、例えば球状の粒子を機械的に塑性変形することで製造することができる。板状の粒子は例えば湿式還元法で製造することができる。樹枝状の銅粒子は例えば電解法で製造することができる。本発明の銅粉は、様々な形状の銅粒子の混合体であってもよい。 The copper particles constituting the copper powder of the present invention are not particularly limited in shape, and can be used in various shapes such as a spherical shape, a flake shape, a plate shape, and a dendritic shape. What shape copper particles are used may be appropriately determined according to the specific application of the copper powder of the present invention. The shape of the copper particles generally depends on the manufacturing method. Spherical copper particles can be produced, for example, by an atomization method or a wet reduction method. The flaky particles can be produced, for example, by mechanically plastically deforming spherical particles. The plate-like particles can be produced, for example, by a wet reduction method. Dendritic copper particles can be produced, for example, by an electrolytic method. The copper powder of the present invention may be a mixture of copper particles having various shapes.
　なお、本発明の銅粉を構成する銅粒子が前記の各形状を呈するとは、本発明の銅粉を電子顕微鏡観察（例えば１０００倍）で観察したときに、前記の各形状を呈する粒子が、個数基準で８０％以上を占める場合を意味する。 In addition, when the copper particle which comprises the copper powder of this invention exhibits each said shape, when the copper powder of this invention is observed by electron microscope observation (for example, 1000 time), the particle | grains which exhibit said each shape , Meaning that the number accounts for 80% or more.
　次に、本発明の銅粉の好適な製造方法について説明する。本発明の銅粉は、各種の方法で製造された原料銅粉を、所定の雰囲気下、適切な条件で酸化することによって好適に製造される。原料銅粉の製造方法に特に制限はないが、球状の銅粒子からなる銅粉を製造する場合には、例えばアトマイズ法を用いることが好適で、平均粒径３μｍ以下の微粒な銅粉を製造する場合には、湿式法が好適である。 Next, a preferred method for producing the copper powder of the present invention will be described. The copper powder of this invention is suitably manufactured by oxidizing the raw material copper powder manufactured by various methods on a suitable condition in a predetermined atmosphere. There are no particular restrictions on the method for producing the raw material copper powder, but when producing copper powder composed of spherical copper particles, for example, it is preferable to use the atomizing method, which produces fine copper powder having an average particle size of 3 μm or less. In this case, a wet method is preferable.
　アトマイズ法としては、ガスアトマイズ法や水アトマイズ法を好ましく採用することができる。粒子形状の均整化を図る場合にはガスアトマイズ法を採用することが好ましい。一方、粒子の微細化を図る場合には水アトマイズ法を採用することが好ましい。ガスアトマイズ法及び水アトマイズ法の中でも、高圧アトマイズ法によれば、粒子を微細かつ均一に製造することができるので特に好ましい。高圧アトマイズ法とは、水アトマイズ法においては、５０ＭＰａ以上１５０ＭＰａ以下程度の水圧力でアトマイズする方法である。ガスアトマイズ法においては、０.５ＭＰａ以上３ＭＰａ以下程度のガス圧力でアトマイズする方法である。 As the atomizing method, a gas atomizing method or a water atomizing method can be preferably employed. In order to make the particle shape uniform, it is preferable to employ a gas atomizing method. On the other hand, it is preferable to employ a water atomizing method when the particles are miniaturized. Among the gas atomization method and the water atomization method, the high pressure atomization method is particularly preferable because the particles can be produced finely and uniformly. The high-pressure atomizing method is a method of atomizing at a water pressure of about 50 MPa to 150 MPa in the water atomizing method. In the gas atomization method, atomization is performed at a gas pressure of about 0.5 MPa to 3 MPa.
　湿式法としては、銅塩水溶液にアルカリ水溶液を添加したスラリーに、還元剤を添加する還元析出法を採用することができる。所定の微粒銅粉を図る場合にはスラリーに還元糖や次亜リン酸、亜硫酸ナトリウムなどの第一還元剤を添加し酸化第一銅スラリーを調整した後、水和ヒドラジン、硫酸ヒドラジンなどのヒドラジン化合物や水素化ホウ素ナトリウムなどの強塩基性還元剤を添加した、二段階還元法などが好ましい。 As the wet method, a reduction precipitation method in which a reducing agent is added to a slurry obtained by adding an alkaline aqueous solution to a copper salt aqueous solution can be employed. When preparing a predetermined fine copper powder, first reducing agents such as reducing sugar, hypophosphorous acid and sodium sulfite are added to the slurry to prepare a cuprous oxide slurry, and then hydrazine such as hydrated hydrazine and hydrazine sulfate. A two-step reduction method in which a strongly basic reducing agent such as a compound or sodium borohydride is added is preferred.
　原料銅粉は、これを酸化処理に付す前に分級してもよい。この分級は、目的とする粒度が中心となるように、適切な分級装置を用いて、得られた原料銅粉から粗粉や微粉を分離することにより容易に実施することができる。分級は、原料銅粉のＤ５０の値が、先に述べた範囲となるように行うことが好ましい。 The raw material copper powder may be classified before being subjected to oxidation treatment. This classification can be easily carried out by separating coarse powder and fine powder from the obtained raw material copper powder using an appropriate classification apparatus so that the target particle size becomes the center. Classification, the value of D 50 of the raw material copper powder, is preferably performed such that the ranges set forth above.
　このようにして得られた原料銅粉を酸化処理に付す。好適な酸化条件としては、例えば相対湿度が４０％ＲＨ以上８０％ＲＨ以下で、かつ温度が６０℃以上１２０℃以下の大気雰囲気下に静置する条件が工業的な処理条件として挙げられる。銅粉の酸化処理の均一性保持と、過剰処理によるＣｕ（II）の増加に伴う粒子凝集の防止の観点から、処理時間は、大気雰囲気の条件が上述の範囲内であることを条件として、２０分以上６５０分以下であることが好ましく、３０分以上６００分以下であることが更に好ましく、３０分以上１８０分以下であることが一層好ましい。相対湿度が低い場合には、酸化速度が遅い傾向にあるので、そのような場合は、温度を高めに設定すればよい。例えば、相対湿度が４０％以上６０％以下の場合は処理温度が７０℃以上１３０℃以下であるのが好ましく、相対湿度が６０％超８０％以下の場合は処理温度が６０℃以上９０℃以下であるのが好ましい。処理中は、大気雰囲気の相対湿度及び温度を一定に保つこと、すなわち恒温恒湿が好ましいが、必要に応じ相対湿度及び／又は温度を変化させながら処理を行ってもよい。 The raw material copper powder thus obtained is subjected to oxidation treatment. Suitable oxidation conditions include, for example, conditions for standing in an air atmosphere having a relative humidity of 40% RH to 80% RH and a temperature of 60 ° C. to 120 ° C. as industrial treatment conditions. From the viewpoint of maintaining uniformity of the oxidation treatment of copper powder and preventing particle aggregation due to an increase in Cu (II) due to excessive treatment, the treatment time is on condition that the atmospheric conditions are within the above range. It is preferably 20 minutes or longer and 650 minutes or shorter, more preferably 30 minutes or longer and 600 minutes or shorter, and even more preferably 30 minutes or longer and 180 minutes or shorter. When the relative humidity is low, the oxidation rate tends to be slow. In such a case, the temperature may be set higher. For example, when the relative humidity is 40% or more and 60% or less, the treatment temperature is preferably 70 ° C. or more and 130 ° C. or less. When the relative humidity is more than 60% and 80% or less, the treatment temperature is 60 ° C. or more and 90 ° C. or less. Is preferred. During the treatment, it is preferable to keep the relative humidity and temperature of the air atmosphere constant, that is, constant temperature and humidity, but the treatment may be performed while changing the relative humidity and / or temperature as necessary.
　酸化の処理の対象となる銅粉としては、例えば水分含有割合の低い乾燥粉を用いることができる。この場合、水分含有割合は例えば０．１質量％以下とすることができる。相対湿度が低い場合には、酸化速度が遅い傾向にあるが、銅粉に水分を添加することで酸化速度を速めることができる。例えば、乾燥銅粉の質量に対して１質量％以上５質量％の範囲で水分を添加した状態下に、銅粉の酸化処理を行うことができる。 As the copper powder to be oxidized, for example, dry powder having a low moisture content can be used. In this case, the moisture content can be set to 0.1% by mass or less, for example. When the relative humidity is low, the oxidation rate tends to be slow, but the oxidation rate can be increased by adding moisture to the copper powder. For example, the oxidation treatment of the copper powder can be performed in a state where moisture is added in the range of 1% by mass to 5% by mass with respect to the mass of the dry copper powder.
　以上の方法によって、目的とする銅粉を首尾よく製造することができる。このようにして得られた銅粉は、銅粒子表面の酸化状態を維持することを目的として、非透湿性材料の容器内に密封し、室温（２５℃）以下の温度で保存することが好ましい。 By the above method, the target copper powder can be successfully produced. The copper powder thus obtained is preferably sealed in a non-moisture permeable material container and stored at a temperature of room temperature (25 ° C.) or lower for the purpose of maintaining the oxidized state of the copper particle surface. .
　本発明の銅粉は、導電特性に優れており、耐酸化性が高く、またガラスフリットとのなじみが良好なので、導電性ペーストや導電性接着剤などの導電性樹脂組成物、あるいは導電性塗料など、各種導電性材料の主要構成材料として好適に用いることができる。 Since the copper powder of the present invention has excellent conductive properties, high oxidation resistance, and good compatibility with glass frit, a conductive resin composition such as a conductive paste or a conductive adhesive, or a conductive paint For example, it can be suitably used as a main constituent material of various conductive materials.
　例えば導電性ペーストを調製するには、本発明の銅粉をバインダ及び溶剤と混合すればよい。こうすることで、高温焼成型導電性ペーストを得ることができる。あるいは、本発明の銅粉を、バインダ及び溶剤、更に必要に応じて硬化剤やカップリング剤、硬化促進剤などと混合して樹脂硬化型導電性ペーストを調製することもできる。 For example, to prepare a conductive paste, the copper powder of the present invention may be mixed with a binder and a solvent. By doing so, a high-temperature fired conductive paste can be obtained. Or the copper powder of this invention can also be mixed with a binder and a solvent, and also a hardening | curing agent, a coupling agent, a hardening accelerator, etc. as needed, and a resin hardening type conductive paste can also be prepared.
　前記のバインダとしては、液状のエポキシ樹脂、アクリル樹脂、フェノール樹脂、不飽和ポリエステル樹脂等を挙げることができるが、これらに限定されるものではない。溶剤としては、テルピネオール、エチルカルビトール、カルビトールアセテート、ブチルセロソルブ、ブチルカルビトールアセテート等が挙げることができる。硬化剤としては、２エチル４メチルイミダゾールなどを挙げることができる。硬化促進剤としては、三級アミン類、三級アミン塩類、イミダゾール類、ホスフィン類、ホスホニウム塩類等を挙げることができる。 Examples of the binder include, but are not limited to, a liquid epoxy resin, an acrylic resin, a phenol resin, and an unsaturated polyester resin. Examples of the solvent include terpineol, ethyl carbitol, carbitol acetate, butyl cellosolve, butyl carbitol acetate and the like. Examples of the curing agent include 2-ethyl 4-methylimidazole. Examples of the curing accelerator include tertiary amines, tertiary amine salts, imidazoles, phosphines, phosphonium salts and the like.
　更に、導電性ペーストを、焼結が必要な酸化物セラミックス電子部品に用いる場合には、酸化物セラミックスへの密着性を向上させる目的で、導電性ペースト中に更にガラスフリットを混合することが好ましい。ガラスフリットとしては、例えばシリカを必須成分として、アルミナ、酸化ホウ素、炭酸カルシウム、酸化チタン、酸化亜鉛、酸化ビスマス、酸化バナジウム、リン酸、酸化アンチモン、酸化鉄、酸化テルル、酸化スズ、酸化セリウム、酸化ランタン及び酸化スズからなる群から選択される少なくとも１種類の酸化物が添加された混合物を加熱溶融し、粉砕したものなどが挙げられる。 Further, when the conductive paste is used for an oxide ceramic electronic component that needs to be sintered, it is preferable to further mix a glass frit in the conductive paste for the purpose of improving adhesion to the oxide ceramic. . As the glass frit, for example, silica as an essential component, alumina, boron oxide, calcium carbonate, titanium oxide, zinc oxide, bismuth oxide, vanadium oxide, phosphoric acid, antimony oxide, iron oxide, tellurium oxide, tin oxide, cerium oxide, Examples thereof include a mixture obtained by heating, melting and pulverizing a mixture to which at least one oxide selected from the group consisting of lanthanum oxide and tin oxide is added.
　本発明の銅粉を含む導電性ペーストは、例えばスクリーン印刷による導体回路形成用や、各種電子部品の電気的接点部材用として好適に使用することができる。例えば、積層セラミックコンデンサの内部電極、インダクタやレジスター等のチップ部品、単板コンデンサ電極、タンタルコンデンサ電極、樹脂多層基板、低温同時焼成セラミック（ＬＴＣＣ）多層基板、アンテナスイッチモジュール、ＰＡモジュールや高周波アクティブフィルター等のモジュールが挙げられる。セラミックス電子部品の絶縁材料としては、アルミナ、ジルコニア、チタニア、フェライト、マグネシア、シリカ等の酸化物セラミックの他、チタン酸バリウム、チタン酸ストロンチウム等のセラミック複合酸化物等が挙げられる。また、絶縁材料として樹脂を用いた電子部品のフレキシブルプリント基板（ＦＰＣ）、ビルドアップ多層配線板などのプリント配線板用電極の他、ＰＤＰ前面板及び背面板やＰＤＰカラーフィルター用電磁遮蔽フィルム、結晶型太陽電池表面電極及び背面引き出し電極、導電性接着剤、ＥＭＩシールド、ＲＦ－ＩＤ、及びＰＣキーボード等のメンブレンスイッチ、異方性導電膜（ＡＣＦ／ＡＣＰ）等にも使用可能である。絶縁材料として樹脂を用いる場合、具体的な樹脂の例としては、エポキシ樹脂、シアネート樹脂、ビスマレイミドトリアジン樹脂（ＢＴ樹脂）、ポリフェニレンエーテル樹脂、フェノール樹脂、ポリイミド樹脂やポリアミド樹脂、不飽和ポリエステル樹脂、液晶ポリマー、ポリエチレンテレフタラート樹脂、ポリエチレンナフタレン樹脂等の絶縁樹脂が挙げられる。また樹脂には、シリカやアルミナ等の各種酸化物無機粒子からなるフィラー粒子等が含有される場合も挙げられる。 The conductive paste containing the copper powder of the present invention can be suitably used, for example, for forming a conductor circuit by screen printing or for electrical contact members of various electronic components. For example, internal electrodes of multilayer ceramic capacitors, chip components such as inductors and resistors, single plate capacitor electrodes, tantalum capacitor electrodes, resin multilayer substrates, low temperature co-fired ceramic (LTCC) multilayer substrates, antenna switch modules, PA modules and high frequency active filters And the like. Examples of insulating materials for ceramic electronic parts include oxide ceramics such as alumina, zirconia, titania, ferrite, magnesia, and silica, and ceramic composite oxides such as barium titanate and strontium titanate. In addition to electrodes for printed wiring boards such as flexible printed circuit boards (FPCs) and build-up multilayer wiring boards for electronic components that use resin as an insulating material, electromagnetic shielding films for PDP front and back plates, PDP color filters, and crystals It can also be used for a type solar cell surface electrode and back surface extraction electrode, conductive adhesive, EMI shield, RF-ID, membrane switch such as PC keyboard, anisotropic conductive film (ACF / ACP) and the like. When using a resin as the insulating material, specific examples of the resin include epoxy resin, cyanate resin, bismaleimide triazine resin (BT resin), polyphenylene ether resin, phenol resin, polyimide resin, polyamide resin, unsaturated polyester resin, Examples thereof include an insulating resin such as a liquid crystal polymer, a polyethylene terephthalate resin, and a polyethylene naphthalene resin. The resin may also contain filler particles made of various oxide inorganic particles such as silica and alumina.
　以下、実施例により本発明を更に詳細に説明する。しかしながら本発明の範囲は、かかる実施例に制限されない。実施例及び比較例に先立ち、原料銅粉の製造について説明する。 Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples. Prior to Examples and Comparative Examples, production of raw material copper powder will be described.
　　〔原料銅粉Ａの製造〕
　電気銅（銅純度：Ｃｕ９９．９５％）を、ガス炉で加熱して溶湯とした。次いで、水アトマイズ装置におけるタンディッシュ中に前記溶湯１００ｋｇを注入し、タンディッシュ底部のノズル（口径５ｍｍ）から溶湯を落下させながら、フルコーン型のノズル（口径２６ｍｍ）の噴射孔から水を逆円錐状の水流形状になるように前記溶湯にジェット噴射（水圧１００ＭＰａ、水量３５０Ｌ／ｍｉｎ）して水アトマイズすることにより銅粉を製造した。
　次に、得られた銅粉を、分級装置（日清エンジニアリング株式会社製「ターボクラシファイア（商品名）ＴＣ－２５（型番）」）により分級し、分級したものを原料銅粉Ａとして用いた。原料銅粉Ａは球状の乾燥粉であり、そのＤ５０及び酸素の含有割合は以下の表１に示すとおりであった。 [Manufacture of raw material copper powder A]
Electric copper (copper purity: Cu 99.95%) was heated in a gas furnace to obtain a molten metal. Next, 100 kg of the molten metal is poured into the tundish in the water atomizing device, and the molten metal is dropped from the nozzle (caliber: 5 mm) at the bottom of the tundish, and water is inverted from the injection hole of the full cone type nozzle (caliber: 26 mm). A copper powder was produced by jetting the water (water pressure: 100 MPa, water amount: 350 L / min) and water atomizing so as to obtain a water flow shape.
Next, the obtained copper powder was classified by a classifier (“Turbo Classifier (trade name) TC-25 (model number)” manufactured by Nissin Engineering Co., Ltd.), and the classified copper powder was used as the raw material copper powder A. The raw material copper powder A was a spherical dry powder, and the D 50 and oxygen content ratios were as shown in Table 1 below.
　　〔原料銅粉Ｂの製造〕
　原料銅粉Ａの製造において、分級装置の分級点を変更した以外は、原料銅粉Ａと同様にして原料銅粉Ｂを得た。原料銅粉Ｂは球状の乾燥粉であり、そのＤ５０及び酸素の含有割合は以下の表１に示すとおりであった。 [Manufacture of raw material copper powder B]
In the production of the raw material copper powder A, the raw material copper powder B was obtained in the same manner as the raw material copper powder A, except that the classification point of the classifier was changed. The raw material copper powder B was a spherical dry powder, and the D 50 and oxygen content ratios were as shown in Table 1 below.
　　〔原料銅粉Ｃの製造〕
　原料銅粉Ａの製造において、分級装置の分級点を変更した以外は、原料銅粉Ａと同様にして原料銅粉Ｃを得た。原料銅粉Ｃは球状の乾燥粉であり、そのＤ５０及び酸素の含有割合は以下の表１に示すとおりであった。 [Manufacture of raw material copper powder C]
In the production of the raw material copper powder A, the raw material copper powder C was obtained in the same manner as the raw material copper powder A, except that the classification point of the classifier was changed. The raw material copper powder C was a spherical dry powder, and the D 50 and oxygen content ratios were as shown in Table 1 below.
　　〔原料銅粉Ｄの製造〕
　硫酸銅（五水塩）１００ｋｇを溶解させて２００Ｌの水溶液とし、これを６０℃に維持しながら、２５質量％水酸化ナトリウム水溶液１２５Ｌ及び４５０ｇ／Ｌのグルコース水溶液８０Ｌを添加して酸化第一銅スラリーを生成した。このスラリーに、更に２０重量％水和ヒドラジン１００Ｌを添加することにより原料銅粉Ｄを得た。原料銅粉Ｄは球状の乾燥粉であり、そのＤ５０及び酸素の含有割合は以下の表１に示すとおりであった。 [Manufacture of raw material copper powder D]
Dissolve 100 kg of copper sulfate (pentahydrate) to make a 200 L aqueous solution. While maintaining this at 60 ° C., add 125 L of 25 mass% aqueous sodium hydroxide and 80 L of 450 g / L glucose aqueous solution to add cuprous oxide. A slurry was produced. A raw material copper powder D was obtained by further adding 100 L of 20 wt% hydrated hydrazine to this slurry. The raw material copper powder D was a spherical dry powder, and the D 50 and oxygen content ratios were as shown in Table 1 below.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　　〔実施例１〕
　１０００ｇの原料銅粉Ａを、８０℃・８０％ＲＨに調温・調湿された恒温恒湿槽内に３０分間静置して大気雰囲気下で酸化処理を行った。このようにして、目的とする銅粉を得た。 [Example 1]
1000 g of the raw material copper powder A was left in a constant temperature and humidity chamber adjusted to 80 ° C. and 80% RH for 30 minutes and subjected to an oxidation treatment in an air atmosphere. Thus, the target copper powder was obtained.
　　〔実施例２ないし１０〕
　以下の表２に示す条件で、同表に示す原料銅粉の酸化処理を行う以外は実施例１と同様にして、目的とする銅粉を得た。 [Examples 2 to 10]
The target copper powder was obtained in the same manner as in Example 1 except that the raw material copper powder shown in the same table was oxidized under the conditions shown in Table 2 below.
　　〔実施例１１及び１２〕
　表２に示す原料銅粉の質量に対して３質量％の水分を添加して該原料銅粉を湿らせた状態下に、同表に示す条件で酸化処理を行う以外は実施例１と同様にして、目的とする銅粉を得た。 Examples 11 and 12
The same as Example 1 except that 3% by mass of water is added to the mass of the raw material copper powder shown in Table 2 and the raw copper powder is moistened under the conditions shown in the same table. Thus, the intended copper powder was obtained.
　　〔実施例１３〕
　表２に示す原料銅粉の質量に対して１質量％の水分を添加して該原料銅粉を湿らせた状態下に、同表に示す条件で酸化処理を行う以外は実施例１と同様にして、目的とする銅粉を得た。 Example 13
The same as Example 1 except that 1% by mass of water is added to the mass of the raw material copper powder shown in Table 2 and the raw copper powder is moistened under the conditions shown in the same table. Thus, the intended copper powder was obtained.
　　〔比較例１ないし４〕
　　原料銅粉ＡないしＤをそのまま用いた。 [Comparative Examples 1 to 4]
The raw material copper powders A to D were used as they were.
　　〔比較例５ないし７〕
　以下の表２に示す条件で、同表に示す原料銅粉の酸化処理を行う以外は実施例１と同様にして、目的とする銅粉を得た。 [Comparative Examples 5 to 7]
The target copper powder was obtained in the same manner as in Example 1 except that the raw material copper powder shown in the same table was oxidized under the conditions shown in Table 2 below.
　　〔比較例８〕
　以下の表２に示す原料銅粉の質量に対して３質量％の水分を添加して該原料銅粉を湿らせた状態下に、同表に示す条件で酸化処理を行う以外は実施例１と同様にして、目的とする銅粉を得た。 [Comparative Example 8]
Example 1 except that 3% by mass of water is added to the mass of the raw material copper powder shown in Table 2 below and the raw copper powder is moistened under the conditions shown in the same table. In the same manner as above, the intended copper powder was obtained.
　　〔評価〕
　実施例及び比較例で得られた銅粉の銅酸化率、酸素の含有割合、Ｄ５０を上述の方法で測定した。また、以下の方法で、収縮開始温度を測定し、更に焼成膜の緻密性及び焼成膜中のガラス均一性を評価した。また、総合評価も行った。その結果を以下の表２に示す。 [Evaluation]
Copper oxide of the copper powder obtained in Examples and Comparative Examples, the content of oxygen was measured D 50 in the manner described above. Further, the shrinkage start temperature was measured by the following method, and the denseness of the fired film and the glass uniformity in the fired film were evaluated. A comprehensive evaluation was also conducted. The results are shown in Table 2 below.
　　〔収縮開始温度〕
　熱機械分析（ＴＭＡ）によって、上述の方法で銅粉の収縮開始温度を測定した。 [Shrinkage start temperature]
By thermomechanical analysis (TMA), the shrinkage start temperature of the copper powder was measured by the method described above.
　　〔焼成膜の緻密性Ｉ〕
　実施例及び比較例で得られた銅粉に、テルピネオール及びアクリル樹脂を添加混合して導電性ペースト（１）を調製した。この導電性ペースト（１）に占める銅粉の割合は７０質量％、テルピネオールの割合は２５質量％、アクリル樹脂の割合は５質量％であった。この導電性ペースト（１）を、アルミナ基板上に、膜厚５０μｍで塗布して塗膜を形成した。この塗膜を窒素雰囲気下、８４５℃で２０分間焼成して焼成膜を得た。得られた焼成膜の表面を、走査型電子顕微鏡（１０００倍）で拡大し、１０視野の画像を撮影した。この１０視野の画像を解析し、以下の基準で緻密性を評価した。なお、ボイド面積比とは、１視野中に含まれるボイド（５μｍ以上）の面積を画像解析により求め、その１０視野の値を算術平均した値である。ボイド面積が多すぎると緻密性が不足、逆に少なすぎると緻密性が高すぎて後述のガラス分布均一性に悪影響を来すものである。緻密性の良否は以下の３段階で評価した。
◎：ボイド面積比が３％以上７％以下である。
○：ボイド面積比が１％以上３％未満、又は７％超１０％以下である。
×：ボイド面積比が１％未満、又は１０％超である。 [Denseness of fired film I]
To the copper powder obtained in Examples and Comparative Examples, terpineol and acrylic resin were added and mixed to prepare a conductive paste (1). The proportion of copper powder in the conductive paste (1) was 70% by mass, the proportion of terpineol was 25% by mass, and the proportion of acrylic resin was 5% by mass. This conductive paste (1) was applied on an alumina substrate with a film thickness of 50 μm to form a coating film. This coating film was baked at 845 ° C. for 20 minutes in a nitrogen atmosphere to obtain a baked film. The surface of the obtained fired film was magnified with a scanning electron microscope (1000 times), and images of 10 fields of view were taken. The images of 10 fields of view were analyzed, and the denseness was evaluated according to the following criteria. The void area ratio is a value obtained by calculating the area of voids (5 μm or more) included in one visual field by image analysis and arithmetically averaging the values of the ten visual fields. If the void area is too large, the denseness is insufficient. Conversely, if the void area is too small, the denseness is too high and adversely affects the glass distribution uniformity described later. The quality of the denseness was evaluated in the following three stages.
A: The void area ratio is 3% or more and 7% or less.
○: The void area ratio is 1% or more and less than 3%, or more than 7% and 10% or less.
X: Void area ratio is less than 1% or more than 10%.
〔焼成膜の密着性II〕
　前記の焼成膜に対して、別の観点から密着性を評価した。詳細には、焼成膜を基板ごと超音波洗浄機に３０秒浸漬させたあと、焼成膜の表面を、走査型電子顕微鏡（１０００倍）で観察し、約１００μｍ四方の観察視野での焼成膜の密着性の良否を以下の３段階で評価した。
◎：焼成膜の剥離が全く観察されない。
○：焼成膜面積の７０％以上が密着している。
×：密着している焼成膜面積が３０％未満である。 [Adhesion of fired film II]
The adhesiveness of the fired film was evaluated from another viewpoint. Specifically, after the fired film is immersed in the ultrasonic cleaner for 30 seconds together with the substrate, the surface of the fired film is observed with a scanning electron microscope (1000 times), and the fired film in an observation field of about 100 μm square is observed. The quality of adhesion was evaluated in the following three stages.
A: No peeling of the fired film is observed.
○: 70% or more of the fired film area is in close contact.
X: The area of the fired film in close contact is less than 30%.
　　〔焼成膜中のガラス分布均一性〕
　実施例及び比較例で得られた銅粉に、テルピネオール、アクリル樹脂（大成ファインケミカル製ＫＷＥ―２５０Ｔ）及びガラスフリット（旭硝子製ＡＳＦ１８９１Ｆ）を添加混合して導電性ペースト（２）を調製した。この導電性ペースト（２）に占める銅粉の割合は７０質量％、テルピネオールの割合は２２質量％、アクリル樹脂の割合は３質量％、ガラスフリットの割合は５質量％であった。その他は前記の焼成膜の緻密性の評価と同様に操作し、焼成膜を得た。焼成膜の表面を視野約１００μｍ四方、１０００倍にて得られる像をＥＤＸ分析し、ガラスフリットに由来するＳｉ量からガラス分布均一性を評価した。評価基準は以下のとおりである。なお、Ｓｉ量はＳｉ×１００／（Ｓｉ＋Ｃｕ）で定義される量である。式中、Ｓｉ及びＣｕはＥＤＸ分析におけるＳｉ及びＣｕのピーク強度を表す。
◎：Ｓｉ量が１％以上１０％以下である。
○：Ｓｉ量が０．５％以上１％未満、又は１０％超２０％以下である。
×：Ｓｉ量が０．５％未満、又は２０％超である。 [Uniformity of glass distribution in the fired film]
To the copper powder obtained in Examples and Comparative Examples, terpineol, acrylic resin (KWE-250T manufactured by Taisei Fine Chemical) and glass frit (ASF 1891F manufactured by Asahi Glass) were added and mixed to prepare a conductive paste (2). The proportion of copper powder in the conductive paste (2) was 70% by mass, the proportion of terpineol was 22% by mass, the proportion of acrylic resin was 3% by mass, and the proportion of glass frit was 5% by mass. Others were operated in the same manner as in the evaluation of the denseness of the fired film to obtain a fired film. The surface of the fired film was subjected to EDX analysis on an image obtained at a field of view of about 100 μm square and 1000 times, and the glass distribution uniformity was evaluated from the amount of Si derived from the glass frit. The evaluation criteria are as follows. The amount of Si is an amount defined by Si × 100 / (Si + Cu). In the formula, Si and Cu represent peak intensities of Si and Cu in EDX analysis.
A: The amount of Si is 1% or more and 10% or less.
○: Si amount is 0.5% or more and less than 1%, or more than 10% and 20% or less
X: The amount of Si is less than 0.5% or more than 20%.
　　〔総合評価〕
上述した評価のうち、総合評価として下記の評価を行った。
◎：緻密性Ｉ、密着性II及び均一性評価のうち、２項目以上が◎である。
○：緻密性Ｉ、密着性II及び均一性評価のうち、１項目以上が○である。
×：緻密性Ｉ、密着性II及び均一性評価のうち、１項目以上に×がある。 〔Comprehensive evaluation〕
Among the evaluations described above, the following evaluations were performed as comprehensive evaluations.
A: Two or more items among the denseness I, the adhesion II, and the uniformity evaluation are A.
○: One item or more among the denseness I, the adhesiveness II, and the uniformity evaluation is ○.
X: Among the denseness I, the adhesiveness II and the uniformity evaluation, there is x in one or more items.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２に示す結果から明らかなとおり、各実施例で得られた銅粉は、比較例の銅粉に比べて酸化開始温度が高く、耐酸化性に優れていることが判る。また、各実施例で得られた銅粉を原料として製造された焼成膜は、比較例の銅粉を原料として製造された焼成膜に比べて、膜の緻密性が高く、しかも銅粉とガラスとのなじみが良好であることが判る。 As is clear from the results shown in Table 2, it can be seen that the copper powder obtained in each example has a higher oxidation start temperature and superior oxidation resistance compared to the copper powder of the comparative example. In addition, the fired film manufactured using the copper powder obtained in each example as a raw material has a higher film density than the fired film manufactured using the copper powder of the comparative example as a raw material, and copper powder and glass It turns out that familiarity with is good.
　本発明によれば、収縮温度制御に優れた銅粉が提供される。この銅粉は、焼成時におけるガラスフリットとのなじみが良好なので、この銅粉を用いることで緻密性に優れた焼成膜を得ることができる。また、この銅粉は、導電性組成物にした際、酸素含有絶縁材料との親和性が高く、密着信頼性の高い電子部品を得ることができる。 According to the present invention, copper powder excellent in shrinkage temperature control is provided. Since this copper powder has good compatibility with the glass frit at the time of firing, a fired film having excellent denseness can be obtained by using this copper powder. Moreover, when this copper powder is made into a conductive composition, it is possible to obtain an electronic component having a high affinity with an oxygen-containing insulating material and a high adhesion reliability.

Claims (7)

  1. 　Ｘ線光電子分光装置（ＸＰＳ）を用いて表面を測定して得られるＸ線光電子分光スペクトルにおいて、Ｃｕ（II）のピーク強度Ｐ２に対する、Ｃｕ（I）のピーク強度Ｐ１及びＣｕ（０）のピーク強度Ｐ０の比率であるＰ２／（Ｐ0＋Ｐ1）の値が０．１５以上１以下である、銅粉。 In an X-ray photoelectron spectrum obtained by measuring a surface using an X-ray photoelectron spectrometer (XPS), Cu (I) peak intensity P 1 and Cu (0) with respect to Cu (II) peak intensity P 2 the value of P 2 / of the ratio of the peak intensity P 0 (P 0 + P 1 ) is 0.15 or more and 1 or less, copper powder.
  2. 　酸素の含有割合が、０．１５質量％以上１．２質量％以下である請求項１に記載の銅粉。 The copper powder according to claim 1, wherein the oxygen content is 0.15 mass% or more and 1.2 mass% or less.
  3. 　レーザー回折散乱式粒度分布測定法による累積体積５０容量％における体積累積粒径Ｄ50が、０．３μｍ以上１０μｍ以下である請求項１又は２に記載の銅粉。 3. The copper powder according to claim 1, wherein a volume cumulative particle diameter D 50 at a cumulative volume of 50% by volume by a laser diffraction / scattering particle size distribution measurement method is from 0.3 μm to 10 μm.
  4. 　請求項１ないし３のいずれか一項に記載の銅粉と、バインダとを含有する導電性組成物。 A conductive composition containing the copper powder according to any one of claims 1 to 3 and a binder.
  5. 　請求項１ないし３のいずれか一項に記載の銅粉を含有する電子部品用電極。 Electrode for electronic parts containing the copper powder as described in any one of Claims 1 thru | or 3.
  6. 　請求項１に記載の銅粉の製造方法であって、
    　乾燥した原料銅粉を、相対湿度が４０％ＲＨ以上８０％ＲＨ以下で、かつ温度が２０℃以上１２０℃以下の大気雰囲気下に、２０分以上６５０分以下静置して酸化処理を行う銅粉の製造方法。     It is a manufacturing method of the copper powder according to claim 1,
    Copper which performs oxidation treatment by leaving the dried raw material copper powder to stand for 20 minutes or more and 650 minutes or less in an air atmosphere having a relative humidity of 40% RH to 80% RH and a temperature of 20 ° C to 120 ° C. Powder manufacturing method.
  7. 　原料銅粉の質量に対して１質量％以上３質量％の範囲で水分を添加した状態下に酸化処理を行う請求項６に記載の銅粉の製造方法。 The manufacturing method of the copper powder of Claim 6 which performs an oxidation process in the state which added the water | moisture content in the range of 1 mass% or more and 3 mass% with respect to the mass of raw material copper powder.
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JP2021055127A (en) * 2019-09-27 2021-04-08 Dic株式会社 Copper/copper oxide fine particle paste

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