WO2022234739A1 - Paste for external electrode - Google Patents

Paste for external electrode Download PDF

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Publication number
WO2022234739A1
WO2022234739A1 PCT/JP2022/013440 JP2022013440W WO2022234739A1 WO 2022234739 A1 WO2022234739 A1 WO 2022234739A1 JP 2022013440 W JP2022013440 W JP 2022013440W WO 2022234739 A1 WO2022234739 A1 WO 2022234739A1
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Prior art keywords
external electrode
solvent
electrode paste
mass
solvents
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PCT/JP2022/013440
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French (fr)
Japanese (ja)
Inventor
直徳 塚本
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株式会社村田製作所
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Priority to JP2023518636A priority Critical patent/JPWO2022234739A1/ja
Priority to KR1020237037687A priority patent/KR20230163557A/en
Publication of WO2022234739A1 publication Critical patent/WO2022234739A1/en

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    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
    • B23K35/36—Selection of non-metallic compositions, e.g. coatings, fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest
    • B23K35/3601—Selection of non-metallic compositions, e.g. coatings, fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest with inorganic compounds as principal constituents
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • 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
    • H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
    • H01B13/0016—Apparatus or processes specially adapted for manufacturing conductors or cables for heat treatment
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
    • H01B3/30—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G4/00—Fixed capacitors; Processes of their manufacture
    • H01G4/002—Details
    • H01G4/018—Dielectrics
    • H01G4/06—Solid dielectrics
    • H01G4/08—Inorganic dielectrics
    • H01G4/12—Ceramic dielectrics
    • H01G4/1209—Ceramic dielectrics characterised by the ceramic dielectric material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G4/00—Fixed capacitors; Processes of their manufacture
    • H01G4/30—Stacked capacitors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/13—Energy storage using capacitors

Definitions

  • the present invention provides an external electrode paste used for forming an external electrode of an electronic component, a method of forming an external electrode in an electronic component using the external electrode paste, and an external electrode using the external electrode paste. and a method of manufacturing an electronic component including forming electrodes.
  • Such external electrode paste generally contains a resin as a binder, a metal filler, and a solvent.
  • Patent Document 1 describes a binder composition containing ethyl cellulose and an acrylic polymer, and the use of such a binder composition for manufacturing laminated ceramic capacitors and the like.
  • This binder composition is a composition in which ethyl cellulose and an acrylic polymer are simply mixed.
  • the present invention is intended to solve the above problems, and is capable of suppressing the expansion of the central portion compared to the end portions when coated, and the generation of voids when the coated film is sintered.
  • External electrode paste a resin; a metal filler; a solvent; including the solvent comprises one or more first solvents and one or more second solvents,
  • the ratio of the mass of the first solvent and the ratio of the mass of the second solvent to the mass of the solvent are each 40% by mass or more,
  • the lowest boiling point T Hl among the boiling points under atmospheric pressure of the one or more second solvents is higher than the highest boiling point T Lh among the boiling points under atmospheric pressure of the one or more first solvents by 10°C or more.
  • the highest boiling point T Hh of the boiling points under atmospheric pressure of the one or more second solvents is T Hl +10° C. or less
  • the lowest boiling point T Ll among the boiling points under atmospheric pressure of the one or more first solvents is T Lh ⁇ 10° C.
  • the solvent may contain a sub-solvent in addition to the first solvent and the second solvent,
  • the boiling point of the secondary solvent under atmospheric pressure is less than (T Ll ⁇ 10)° C., more than (T Lh +10)° C. and less than (T Hl ⁇ 10)° C., or more than (T Hh +10)° C. for the external electrode. Paste.
  • a method for forming an external electrode in an electronic component includes: A step of preparing an electronic component element; a step of applying the external electrode paste to the outer surface of the electronic component element; and baking the external electrode paste applied to the outer surface of the electronic component element.
  • the method for manufacturing an electronic component is a method that includes the step of forming external electrodes by the method for forming external electrodes described above.
  • the external electrode paste of the present invention it is possible to suppress swelling of the center portion compared to the end portions when the paste is applied, and the generation of voids when the coated film is sintered. Therefore, electronic components manufactured using the aforementioned external electrode paste are miniaturized.
  • FIG. 4 is a drawing for explaining the process of applying the external electrode paste to the ceramic body, (a) showing a state in which the ceramic body is immersed in the external electrode paste, and (b) showing the ceramic body. (c) shows an outward flow in which the external electrode paste flows from the center to the end, and (d) shows a dried state of the external electrode paste.
  • FIG. 4 is a diagram showing the external shape and cutting position of a ceramic body used when examining the flatness of the external electrode paste.
  • (a) is a diagram schematically showing a cross section of a multilayer ceramic capacitor in which external electrodes are formed using the paste for external electrodes of the present invention
  • (b) is a diagram showing external electrodes formed using a conventional paste for external electrodes.
  • 1 is a diagram schematically showing a cross section of a laminated ceramic capacitor in which .
  • the external electrode paste in one embodiment contains a resin, a metal filler, and a solvent.
  • the resin, metal filler, and solvent are described in detail below.
  • the type of resin is not particularly limited as long as the desired effects are not inhibited.
  • various resins conventionally blended in external electrode pastes can be used without particular limitation.
  • Preferred resins include, for example, cellulose-based resins, acrylic-based resins, and butyral-based resins. It is particularly preferable that the resin contains a cellulose-based resin because it is easy to obtain an external electrode paste having a viscosity suitable for forming the external electrodes. It is also preferred that the resin comprises a copolymer resin having blocks derived from cellulosic resins. Such copolymer resin may be a block copolymer or a graft copolymer.
  • the cellulosic resin is, for example, at least one of ethyl cellulose, methyl cellulose, hydroxypropyl cellulose, trityl cellulose, acetyl cellulose, carboxymethyl cellulose, and nitrocellulose.
  • the acrylic resin is, for example, a homopolymer of one or more monomers consisting of isobutyl methacrylate, methyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, n-butyl methacrylate, and 2-ethylhexyl methacrylate. or a copolymer.
  • the metal filler is made of metal that constitutes the external electrodes.
  • the type of metal that constitutes the metal filler is appropriately selected according to the type of metal that constitutes the external electrode.
  • Preferred metals are copper (Cu), silver (Ag), nickel (Ni), and alloys containing these metals, because of their excellent conductivity and easy availability of metal fillers with desired particle sizes.
  • the alloy containing these metals preferably contains one or more selected from the group consisting of copper (Cu), silver (Ag) and nickel (Ni). Also, the alloy containing these metals preferably contains tin (Sn).
  • the metal filler preferably has a coat layer on its surface.
  • a method for forming the coat layer is not particularly limited.
  • the metal filler may be coated with a coating layer by drying the solution adhering to the metal filler while spraying the solution of the coating agent toward the air current containing the metal filler.
  • a coating agent capable of adhering or bonding to the metal surface may be adhered or bonded to the surface of the metal filler to form a coating layer.
  • Coating agents include silane coupling agents, titanium coupling agents, aluminum coupling agents, aliphatic carboxylic acids, aliphatic thiols, and amine coupling agents.
  • These coating agents may be used individually by 1 type, or may be used in combination of 2 or more type.
  • aliphatic carboxylic acids and silane coupling agents are preferred because they have good bonding properties to the surface of the metal filler, and are inexpensive and readily available.
  • Silane coupling agents include, for example, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane.
  • the particle diameter of the metal filler is preferably 80 nm or more and 1000 nm or less, more preferably 90 nm or more and 800 nm or less, and particularly preferably 100 nm or more and 500 nm or less.
  • the particle size of the metal filler is the median system D50 obtained by observing the metal filler with a scanning electron microscope.
  • the particle size of the metal filler includes the thickness of the coat layer.
  • the external electrode paste contains a solvent as a component that dissolves the aforementioned resin, disperses the metal filler, and imparts fluidity to the paste.
  • the solvent includes one or more first solvents and one or more second solvents.
  • the ratio of the mass of the first solvent and the ratio of the mass of the second solvent to the mass of the solvent are each 40% by mass or more.
  • the lowest boiling point T Hl among the boiling points under atmospheric pressure of the one or more second solvents is higher than the highest boiling point T Lh among the boiling points under atmospheric pressure of the one or more first solvents by 10°C or more.
  • the highest boiling point T Hh among the boiling points under atmospheric pressure of the one or more second solvents is T Hl +10° C. or less.
  • the lowest boiling point T Ll among the boiling points under atmospheric pressure of the one or more first solvents is T Lh ⁇ 10° C. or higher.
  • the solvent may contain a sub-solvent in addition to the first solvent and the second solvent.
  • the solvent consists of a first solvent and a second solvent, or consists of a first solvent, a second solvent and a secondary solvent.
  • the boiling point of the secondary solvent under atmospheric pressure is less than (T Ll ⁇ 10)° C., more than (T Lh +10)° C. and less than (T Hl ⁇ 10)° C., or more than (T Hh +10)° C. for the external electrode. Paste.
  • the solvent includes one or more first solvents and one or more second solvents.
  • the number of first solvents is preferably one or two, preferably one.
  • the number of second solvents is one or two.
  • the ratio of the mass of the first solvent and the ratio of the mass of the second solvent to the mass of the solvent are each 40% by mass or more.
  • it is easy to prevent the central portion from swelling compared to the end portions. is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 100% by mass.
  • the lowest atmospheric pressure boiling point T Hl of the one or more second solvents is 10 times higher than the highest atmospheric pressure boiling point T Lh of the one or more first solvent °C or higher. Since the external electrode paste contains the second solvent and the first solvent that satisfy such a difference in boiling point, swelling of the center portion compared to the end portions is suppressed when the external electrode paste is applied. It's easy to do.
  • T Hl is preferably 20° C. or more higher than T Lh , more preferably 30° C. or more.
  • T Hl is preferably (T Lh +100) ° C. or less, more preferably (T Lh +80) ° C. or less, and (T Lh +50)°C or less is more preferable.
  • the boiling point under atmospheric pressure of each of the one or more solvents constituting the second solvent is not particularly limited as long as the desired effect can be obtained.
  • the boiling point under atmospheric pressure of the one or more solvents constituting the second solvent is preferably 200° C. or higher and 300° C. or lower, more preferably 210° C. or higher and 250° C. or lower.
  • the boiling point under atmospheric pressure of each of the one or more solvents constituting the first solvent is not particularly limited as long as the desired effect can be obtained.
  • the boiling point under atmospheric pressure of the one or more solvents constituting the first solvent is preferably 150° C. or higher and 240° C. or lower, more preferably 200° C. or higher and 230° C. or lower.
  • the difference between the weighted average value of the surface tension of the second solvent and the weighted average value of the surface tension of the first solvent is preferably 3 mN/m or more, more preferably 8 mN/m or more. Either the surface tension of the first solvent or the surface tension of the second solvent may be higher.
  • the weighted average value of the surface tension of the second solvent and the weighted average value of the surface tension of the first solvent satisfy the above relationship, when the external electrode paste is applied to form a film, the end portion It is easy to suppress swelling of the central portion compared to .
  • the weighted average value of the surface tension of the second solvent is preferably 23 mN/m or more and 50 mN/m or less.
  • the weighted average value of the surface tension of the first solvent is preferably 20 mN/m or more and 47 mN/m or less.
  • the ratio of the solvent mass to the mass of the external electrode paste is preferably 35% by mass or more and 50% by mass or less, more preferably 37.5% by mass or more and 45% by mass or less.
  • solvents include texanol, propylene glycol monophenyl ether, butyl carbitol, terpene solvents, diethylene glycol, carbitol acetate, butyl carbitol acetate, benzyl alcohol, methylpropylene diglycol, diphenyl ether, ethylene glycol, and the like. is mentioned.
  • the external electrode paste may contain optional components such as a glass frit, a dispersant, and a thickener along with the resin and metal filler described above. These optional components are appropriately used in consideration of the amount normally used in the external electrode paste.
  • the external electrode paste can be obtained by dissolving and dispersing the resins and metal fillers described above, and optionally the above-described optional components, in a desired ratio in a solvent that satisfies the above-described predetermined requirements. .
  • FIG. 1 is a diagram for explaining the process of applying the external electrode paste 11 to the ceramic body 12 in this embodiment.
  • the regions where the external electrodes of the ceramic body 12 are to be formed are immersed in the external electrode paste 11 (see FIG. 1(a)).
  • the ceramic body 12 is pulled up (see FIG. 1(b)).
  • the regions where the external electrodes are formed are, for example, both end faces of the ceramic body 12 .
  • the external electrode paste applied to the ceramic body 12 is denoted by 11a.
  • the coating amount of the external electrode paste is smaller at the end part, and the gas-liquid interface per volume at the end part is larger. For this reason, drying progresses more easily at the ends. Therefore, the ratio of the solid content (resin and metal filler) in the external electrode paste is higher in the end portion than in the center portion. As a result, the solid-liquid interface increases at the edge relative to the center, making the edge energetically unstable.
  • the first solvent preferentially volatilizes. For these reasons, the solvent moves from the central portion to the end portions so that the concentration gradient of the solid content in the external electrode paste is relaxed. Also, convection of the solvent from the center to the ends is generated so that the composition of the solvent is homogenized.
  • the solvent moves so that the composition of the solvent becomes uniform during the process of drying the external electrode paste 11a on the ceramic body 12. .
  • This solvent movement serves to promote outward flow. Due to the strong outward flow, the external electrode paste 11a flows from the central portion to the end portions. Therefore, it is possible to prevent the external electrode paste 11a from swelling outward in the central portion (see FIG. 1(d)).
  • the external electrode paste in the present embodiment contains predetermined amounts of the above-described second solvent and first solvent as solvents, and therefore has better fluidity than conventional external electrode pastes.
  • the use of the external electrode paste according to the present embodiment can suppress swelling of the center portion compared to the end portions. Therefore, an electronic component manufactured using the external electrode paste in this embodiment is miniaturized.
  • FIG. 2(a) is a diagram schematically showing a cross section of a multilayer ceramic capacitor 20a in which external electrodes 22a are formed on a ceramic body 21a using the external electrode paste of the present embodiment.
  • FIG. 2(b) is a schematic cross-sectional view of a multilayer ceramic capacitor 20b in which external electrodes 22b are formed on a ceramic body 21b using a conventional external electrode paste.
  • the shape of the external electrode 22b formed using the conventional external electrode paste is a convex shape with a thick central portion and thin end portions.
  • the shape of the external electrode 22a formed using the external electrode paste in the present embodiment is a flat shape in which swelling at the central portion is suppressed. Therefore, by forming the external electrodes using the external electrode paste of the present embodiment, the size of the multilayer ceramic capacitor can be reduced. In addition, when compared with the same size, the external electrodes can be made thinner and the internal elements can be made larger, so that the capacity can be increased.
  • the method of applying the external electrode paste to the ceramic body in this embodiment is not limited to the immersion in the external electrode paste described above.
  • the external electrode paste described above can be used when forming external electrodes of electronic components, such as multilayer ceramic capacitors.
  • An electronic component manufactured using this external electrode paste includes the steps of preparing an electronic component element, applying the external electrode paste of the present embodiment to the outer surface of the electronic component element, and applying the applied external and a step of forming the external electrodes by baking the electrode paste.
  • a step of drying the external electrode paste may be included between the step of applying the external electrode paste and the step of baking the applied external electrode paste.
  • An electronic component element has, for example, a structure in which a plurality of ceramic layers and internal electrodes are alternately laminated.
  • solvents S1 to S5 having the following boiling points and surface tensions were used.
  • the boiling point described below is a boiling point under atmospheric pressure.
  • S1 Boiling point 244°C, surface tension 26mN/m
  • S2 Boiling point 205°C, surface tension 48mN/m
  • S3 Boiling point 244°C, surface tension 28mN/m
  • S4 Boiling point 218°C, surface tension 31mN/m
  • S5 Boiling point 220°C, surface tension 29mN/m
  • Example 1 In Examples 1 to 8, Examples 10 to 18, Comparative Examples 1, and 2, copper fine particles having the average diameter shown in Table 2 and provided with a coat layer were used as metal fillers. In Example 9, the same particles having the average diameter shown in Table 2 and having no coating layer were used as the metal filler.
  • a ceramic body 40 having a dimension in the length direction L of 1.0 mm, a dimension in the width direction W of 0.5 mm, and a dimension in the thickness direction T of 0.5 mm was prepared.
  • This ceramic body 40 was formed by firing a laminated body in which a plurality of ceramic green sheets, which constitute a laminated ceramic capacitor after formation of external electrodes and were coated with paste for internal electrodes, were laminated.
  • the internal electrodes 42 were exposed on the end face 41 of the ceramic body 40 and the end face located on the opposite side of the end face 41 in the length direction L. As shown in FIG.
  • the external electrode paste applied to the end face 41 of the ceramic body 40 and its periphery was dried. Then, the difference in film thickness of the external electrode paste was examined when the ceramic body 40 was cut along the AA cutting line and the BB cutting line shown in FIG. More specifically, the thickness of the thickest part of the thickness of the external electrode paste at the position where the ceramic body 40 is cut along the AA cutting line, and the thickness of the ceramic body 40 at the BB cut The difference between the film thickness of the thinnest portion of the film thickness of the external electrode paste at the position cut along the line was examined.
  • the film thickness at the thickest portion is the film thickness at the central position in the thickness direction T. is.
  • the film thickness at the thinnest portion is the film thickness at the end in the thickness direction T. is.
  • the AA cutting line is the cutting line along the plane defined by the length direction L and the thickness direction T at the center position of the width direction W of the ceramic body 40.
  • the BB cutting line is a line parallel to the AA cutting line and is a cutting line at the position of the end of the internal electrode 42 in the width direction W of the ceramic body 40 .
  • the position of the BB cutting line is, for example, a position 30 ⁇ m inside in the width direction W from the end of the ceramic body 40 in the width direction.
  • ⁇ Density (void) evaluation> After the external electrode pastes of each example and comparative example were formed into films in the same manner as in the flatness evaluation, the obtained films were sintered at a maximum temperature of 750° C. in a nitrogen atmosphere. The sintered film was observed with a scanning electron microscope (SEM) from a direction substantially perpendicular to the end surface 41 of the ceramic body 40 . From the observed image obtained, the ratio of the area of the void portion to the area of the film after sintering was obtained. A case in which the area ratio of void portions was less than 1.6% was evaluated as ⁇ . A case where the ratio of the area of the void portion was 1.6% or more and less than 2.0% was evaluated as ⁇ . A case where the area ratio of the void portion was 2.0% or more was determined as x.
  • the external electrode paste contains a combination of the first solvent and the second solvent so as to satisfy the above-described predetermined requirements, when it is applied, it is It can be seen that it is possible to suppress the central part from becoming swollen, and to suppress the generation of voids when the coated film is sintered.
  • Comparative Examples 1 and 2 when the external electrode paste does not contain a combination of the first solvent and the second solvent so as to satisfy the above-described predetermined requirements, when coated, It can be seen that it is not possible to simultaneously suppress the formation of a shape in which the center portion swells more than the end portions and suppress the generation of voids when the coated film is sintered.

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Abstract

Provided are: a paste for an external electrode which makes it possible to suppress swelling of a central section compared to an end section when used for coating and suppress the occurrence of voids when a film is sintered after coating; a method for forming an external electrode in an electronic component using the paste for an external electrode; and a method for producing an electronic component including formation of an external electrode using the paste for an external electrode.　The paste for an external electrode includes a resin, a metal filler, and a solvent. The solvent used includes a combination of predetermined amounts of each of a first solvent and a second solvent satisfying a predetermined relationship regarding the boiling points thereof at atmospheric pressure.

Description

外部電極用ペーストExternal electrode paste
　本発明は、電子部品の外部電極を形成するために用いられる外部電極用ペーストと、前述の外部電極用ペーストを用いる電子部品における外部電極の形成方法と、前述の外部電極用ペーストを用いて外部電極を形成することを含む電子部品の製造方法と、に関する。 The present invention provides an external electrode paste used for forming an external electrode of an electronic component, a method of forming an external electrode in an electronic component using the external electrode paste, and an external electrode using the external electrode paste. and a method of manufacturing an electronic component including forming electrodes.
　従来より、外部電極用ペーストを用いて、積層セラミックコンデンサ等の電子部品の外部電極を形成する方法が知られている。そのような外部電極用ペーストは、一般的に、バインダとしての樹脂と、金属フィラーと、溶剤とを含む。 Conventionally, a method of forming external electrodes of electronic components such as multilayer ceramic capacitors using external electrode paste has been known. Such external electrode paste generally contains a resin as a binder, a metal filler, and a solvent.
　特許文献１には、エチルセルロースとアクリル系重合体とを含有したバインダ組成物と、そのようなバインダ組成物を積層セラミックコンデンサ等の製造に用いることとが記載されている。このバインダ組成物は、エチルセルロースとアクリル系重合体とが単に混合された組成物である。 Patent Document 1 describes a binder composition containing ethyl cellulose and an acrylic polymer, and the use of such a binder composition for manufacturing laminated ceramic capacitors and the like. This binder composition is a composition in which ethyl cellulose and an acrylic polymer are simply mixed.
特開２０１３－７１９８６号公報JP 2013-71986 A
　特許文献１に記載のバインダ組成物を含む外部電極用ペーストのような、従来の外部電極用ペーストをセラミック素体に塗工すると、表面張力等の影響により、端部に比べて中央部が膨らむ。したがって、形成される外部電極は、中央部が厚く、端部が薄い凸状の形状となる。このため、電子部品の小型化が難しくなる。
　また、特許文献１に記載されるような従来のバインダ組成物を用いる場合、塗工後の膜を焼結した際にボイドが発生しやすい場合があった。 When a conventional external electrode paste, such as the external electrode paste containing the binder composition described in Patent Document 1, is applied to a ceramic body, the central portion expands compared to the end portions due to the effects of surface tension and the like. . Therefore, the formed external electrode has a convex shape with a thick central portion and thin end portions. Therefore, miniaturization of electronic components becomes difficult.
Moreover, when using a conventional binder composition such as that described in Patent Document 1, voids are likely to occur when the coated film is sintered.
　本発明は、上記課題を解決するものであり、塗工したときに、端部に比べて中央部が膨らむことと、塗工後の膜を焼結した際のボイドの発生とを抑制できる外部電極用ペーストを提供することと、前述の外部電極用ペーストを用いる電子部品における外部電極の形成方法と、前述の外部電極用ペーストを用いて外部電極を形成することを含む電子部品の製造方法とを目的とする。 The present invention is intended to solve the above problems, and is capable of suppressing the expansion of the central portion compared to the end portions when coated, and the generation of voids when the coated film is sintered. Providing an electrode paste, a method of forming an external electrode in an electronic component using the above-described external electrode paste, and a method of manufacturing an electronic component including forming the external electrode using the above-described external electrode paste. With the goal.
　外部電極用ペーストは、
　樹脂と、
　金属フィラーと、
　溶剤と、
を含み、
　溶剤が、１種以上の第１溶剤と、１種以上の第２溶剤とを含み、
　溶剤の質量に対する、第１溶剤の質量の比率と、第２溶剤の質量の比率とが、それぞれ４０質量％以上であり、
　１種以上の第２溶剤の大気圧下での沸点のうち最も低い沸点ＴＨｌが、１種以上の第１溶剤の大気圧下での沸点のうち最も高い沸点ＴＬｈよりも１０℃以上高く、
　１種以上の第２溶剤の大気圧下での沸点のうち最も高い沸点ＴＨｈが、ＴＨｌ＋１０℃以下であり、
　１種以上の第１溶剤の大気圧下での沸点のうち最も低い沸点ＴＬｌが、ＴＬｈ－１０℃以上であり、
　溶剤は、第１溶剤及び第２溶剤以外に副溶剤を含んでいてもよく、
　副溶剤の大気圧下での沸点は、（ＴＬｌ－１０）℃未満、（ＴＬｈ＋１０）℃超（ＴＨｌ－１０）℃未満、又は（ＴＨｈ＋１０）℃超である、外部電極用ペーストである。 External electrode paste
a resin;
a metal filler;
a solvent;
including
the solvent comprises one or more first solvents and one or more second solvents,
The ratio of the mass of the first solvent and the ratio of the mass of the second solvent to the mass of the solvent are each 40% by mass or more,
The lowest boiling point T Hl among the boiling points under atmospheric pressure of the one or more second solvents is higher than the highest boiling point T Lh among the boiling points under atmospheric pressure of the one or more first solvents by 10°C or more. ,
The highest boiling point T Hh of the boiling points under atmospheric pressure of the one or more second solvents is T Hl +10° C. or less,
The lowest boiling point T Ll among the boiling points under atmospheric pressure of the one or more first solvents is T Lh −10° C. or higher,
The solvent may contain a sub-solvent in addition to the first solvent and the second solvent,
The boiling point of the secondary solvent under atmospheric pressure is less than (T Ll −10)° C., more than (T Lh +10)° C. and less than (T Hl −10)° C., or more than (T Hh +10)° C. for the external electrode. Paste.
　電子部品における外部電極の形成方法は、
　電子部品素子を準備する工程と、
　電子部品素子の外表面に、前述の外部電極用ペーストを付与する工程と、
　電子部品素子の外表面に付与された外部電極用ペーストを焼き付ける工程とを含む方法である。 A method for forming an external electrode in an electronic component includes:
A step of preparing an electronic component element;
a step of applying the external electrode paste to the outer surface of the electronic component element;
and baking the external electrode paste applied to the outer surface of the electronic component element.
　電子部品の製造方法は、前述の外部電極の形成方法により外部電極を形成する工程を含む、方法である。 The method for manufacturing an electronic component is a method that includes the step of forming external electrodes by the method for forming external electrodes described above.
　本発明の外部電極用ペーストによれば、塗工したときに、端部に比べて中央部が膨らむことと、塗工後の膜を焼結した際のボイドの発生とを抑制できる。従って、前述の外部電極用ペーストを用いて作製される電子部品は、小型化される。 According to the external electrode paste of the present invention, it is possible to suppress swelling of the center portion compared to the end portions when the paste is applied, and the generation of voids when the coated film is sintered. Therefore, electronic components manufactured using the aforementioned external electrode paste are miniaturized.
外部電極用ペーストを、セラミック素体に塗工する工程を説明するための図であって、（ａ）はセラミック素体を外部電極用ペーストに浸漬した状態を示し、（ｂ）はセラミック素体を引き上げた状態を示し、（ｃ）は中央部から端部へと外部電極用ペーストが流れる外向流が生じる様子を示し、（ｄ）は外部電極用ペーストが乾燥した状態を示す。FIG. 4 is a drawing for explaining the process of applying the external electrode paste to the ceramic body, (a) showing a state in which the ceramic body is immersed in the external electrode paste, and (b) showing the ceramic body. (c) shows an outward flow in which the external electrode paste flows from the center to the end, and (d) shows a dried state of the external electrode paste. 外部電極用ペーストの平坦性を調べる際に用いたセラミック素体の外観形状及び切断位置を示す図である。FIG. 4 is a diagram showing the external shape and cutting position of a ceramic body used when examining the flatness of the external electrode paste. （ａ）は、本発明の外部電極用ペーストを用いて外部電極を形成した積層セラミックコンデンサの断面を模式的に示す図であり、（ｂ）は、従来の外部電極用ペーストを用いて外部電極を形成した積層セラミックコンデンサの断面を模式的に示す図である。(a) is a diagram schematically showing a cross section of a multilayer ceramic capacitor in which external electrodes are formed using the paste for external electrodes of the present invention, and (b) is a diagram showing external electrodes formed using a conventional paste for external electrodes. 1 is a diagram schematically showing a cross section of a laminated ceramic capacitor in which .
　以下に本発明の実施形態を示して、本発明の特徴を具体的に説明する。 The features of the present invention will be specifically described below by showing embodiments of the present invention.
　一実施の形態における外部電極用ペーストは、樹脂と、金属フィラーと、溶剤とを含む。樹脂、金属フィラー、及び溶剤について詳細に後述する。 The external electrode paste in one embodiment contains a resin, a metal filler, and a solvent. The resin, metal filler, and solvent are described in detail below.
　樹脂の種類は、所望する効果が阻害されない限りにおいて特に限定されない。樹脂としては、従来より、外部電極用ペーストに配合されている種々の樹脂を特に限定なく用いることができる。
　好ましい樹脂としては、例えば、セルロース系樹脂、アクリル系樹脂、及びブチラール系樹脂が例示される。外部電極形成に適した粘度の外部電極用ペーストを得やすい点から、樹脂が、セルロース系樹脂を含むのが特に好ましい。
　樹脂が、セルロース系樹脂に由来するブロックを有する共重合樹脂を含むのも好ましい。かかる共重合樹脂は、ブロック共重合体であっても、グラフト共重合体であってもよい。 The type of resin is not particularly limited as long as the desired effects are not inhibited. As the resin, various resins conventionally blended in external electrode pastes can be used without particular limitation.
Preferred resins include, for example, cellulose-based resins, acrylic-based resins, and butyral-based resins. It is particularly preferable that the resin contains a cellulose-based resin because it is easy to obtain an external electrode paste having a viscosity suitable for forming the external electrodes.
It is also preferred that the resin comprises a copolymer resin having blocks derived from cellulosic resins. Such copolymer resin may be a block copolymer or a graft copolymer.
　セルロース系樹脂は、例えば、エチルセルロース、メチルセルロース、ヒドロキシプロピルセルロース、トリチルセルロース、アセチルセルロース、カルボキシメチルセルロース、及び、ニトロセルロースのうちの少なくとも１つである。 The cellulosic resin is, for example, at least one of ethyl cellulose, methyl cellulose, hydroxypropyl cellulose, trityl cellulose, acetyl cellulose, carboxymethyl cellulose, and nitrocellulose.
　アクリル系樹脂は、例えば、メタクリル酸イソブチル、メタクリル酸メチル、メタクリル酸ヒドロキシエチル、メタクリル酸ヒドロキシプロピル、メタクリル酸ｎブチル、及び、メタクリル酸２－エチルヘキシルからなる１種以上の単量体の単独重合体又は共重合体である。 The acrylic resin is, for example, a homopolymer of one or more monomers consisting of isobutyl methacrylate, methyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, n-butyl methacrylate, and 2-ethylhexyl methacrylate. or a copolymer.
　金属フィラーは、外部電極を構成する金属からなる。金属フィラーを構成する金属の種類は、外部電極を構成する金属の種類に応じて適宜選択される。
　導電性に優れることや、所望の粒子径の金属フィラーを入手しやすい点等から、金属としては銅（Ｃｕ）、銀（Ａｇ）、ニッケル（Ｎｉ）、又はこれらの金属を含む合金が好ましい。これらの金属を含む合金は、銅（Ｃｕ）、銀（Ａｇ）、ニッケル（Ｎｉ）からなる群より選択される１種以上を含むのが好ましい。また、これらの金属を含む合金が錫（Ｓｎ）を含むのも好ましい。 The metal filler is made of metal that constitutes the external electrodes. The type of metal that constitutes the metal filler is appropriately selected according to the type of metal that constitutes the external electrode.
Preferred metals are copper (Cu), silver (Ag), nickel (Ni), and alloys containing these metals, because of their excellent conductivity and easy availability of metal fillers with desired particle sizes. The alloy containing these metals preferably contains one or more selected from the group consisting of copper (Cu), silver (Ag) and nickel (Ni). Also, the alloy containing these metals preferably contains tin (Sn).
　後述する溶剤に対する金属フィラーの濡れ性の改良の点で、金属フィラーは、その表面にコート層を備えるのが好ましい。コート層を形成する方法は特に限定されない。例えば、金属フィラーを含む気流にむけてコート剤の溶液を噴霧ししつつ、金属フィラーに付着した溶液を乾燥させて金属フィラーをコート層によりコートしてもよい。また、金属表面に対して、付着又は結合しうるコート剤を、金属フィラー表面に付着又は結合させてコート層を形成してもよい。コート剤としては、シランカップリング剤、チタンカップリング剤、アルミニウムカップリング剤、脂肪族カルボン酸、脂肪族チオール、及びアミンカップリング剤等が挙げられる。これらのコート剤は、１種を単独で使用されても、２種以上を組み合わせて使用されてもよい。これらの中では、金属フィラー表面への結合性が良好であり、安価且つ入手が容易であることから、脂肪族カルボン酸、及びシランカップリング剤が好ましい。 From the viewpoint of improving the wettability of the metal filler to the solvent described later, the metal filler preferably has a coat layer on its surface. A method for forming the coat layer is not particularly limited. For example, the metal filler may be coated with a coating layer by drying the solution adhering to the metal filler while spraying the solution of the coating agent toward the air current containing the metal filler. Alternatively, a coating agent capable of adhering or bonding to the metal surface may be adhered or bonded to the surface of the metal filler to form a coating layer. Coating agents include silane coupling agents, titanium coupling agents, aluminum coupling agents, aliphatic carboxylic acids, aliphatic thiols, and amine coupling agents. These coating agents may be used individually by 1 type, or may be used in combination of 2 or more type. Among these, aliphatic carboxylic acids and silane coupling agents are preferred because they have good bonding properties to the surface of the metal filler, and are inexpensive and readily available.
　シランカップリング剤としては、例えば、メチルトリメトキシシラン、ジメチルジメトキシシラン、フェニルトリメトキシシラン、メチルトリエトキシシラン、ジメチルジエトキシシラン、フェニルトリエトキシシラン、ｎ－プロピルトリメトキシシラン、ｎ－プロピルトリエトキシシラン、ｎ－ヘキシルトリメトキシシラン、ｎ－ヘキシルトリエトキシシラン、ｎ－オクチルトリエトキシシラン、１，６－ビス（トリメトキシシリル）ヘキサン、及びトリフルオロプロピルトリメトキシシラン等が挙げられる。 Silane coupling agents include, for example, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane. silane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-octyltriethoxysilane, 1,6-bis(trimethoxysilyl)hexane, trifluoropropyltrimethoxysilane, and the like.
　金属フィラーの粒子径は、８０ｎｍ以上１０００ｎｍ以下が好ましく、９０ｎｍ以上８００ｎｍ以下がより好ましく、１００ｎｍ以上５００ｎｍ以下が特に好ましい。ここで、金属フィラーの粒子径は、金属フィラーを走査型電子顕微鏡により観察して求められたメジアン系Ｄ５０である。また、金属フィラーがコート層を含む場合、金属フィラーの粒子径は、コート層の厚さを含む。 The particle diameter of the metal filler is preferably 80 nm or more and 1000 nm or less, more preferably 90 nm or more and 800 nm or less, and particularly preferably 100 nm or more and 500 nm or less. Here, the particle size of the metal filler is the median system D50 obtained by observing the metal filler with a scanning electron microscope. Moreover, when the metal filler includes a coat layer, the particle size of the metal filler includes the thickness of the coat layer.
　外部電極用ペーストは、前述の樹脂を溶解させるとともに、金属フィラーを分散させ、ペーストに流動性を付与する成分として溶剤を含む。 The external electrode paste contains a solvent as a component that dissolves the aforementioned resin, disperses the metal filler, and imparts fluidity to the paste.
　溶剤は、１種以上の第１溶剤と、１種以上の第２溶剤とを含む。
　溶剤の質量に対する、第１溶剤の質量の比率と、第２溶剤の質量の比率とが、それぞれ４０質量％以上である。
　１種以上の第２溶剤の大気圧下での沸点のうち最も低い沸点ＴＨｌが、１種以上の第１溶剤の大気圧下での沸点のうち最も高い沸点ＴＬｈよりも１０℃以上高い。
　１種以上の第２溶剤の大気圧下での沸点のうち最も高い沸点ＴＨｈが、ＴＨｌ＋１０℃以下である。
　１種以上の第１溶剤の大気圧下での沸点のうち最も低い沸点ＴＬｌが、ＴＬｈ－１０℃以上である。
　溶剤は、第１溶剤及び第２溶剤以外に副溶剤を含んでいてもよい。
　溶剤は、第１溶剤及び第２溶剤からなるか、第１溶剤、第２溶剤、及び副溶剤からなる。
　副溶剤の大気圧下での沸点は、（ＴＬｌ－１０）℃未満、（ＴＬｈ＋１０）℃超（ＴＨｌ－１０）℃未満、又は（ＴＨｈ＋１０）℃超である、外部電極用ペーストである。 The solvent includes one or more first solvents and one or more second solvents.
The ratio of the mass of the first solvent and the ratio of the mass of the second solvent to the mass of the solvent are each 40% by mass or more.
The lowest boiling point T Hl among the boiling points under atmospheric pressure of the one or more second solvents is higher than the highest boiling point T Lh among the boiling points under atmospheric pressure of the one or more first solvents by 10°C or more. .
The highest boiling point T Hh among the boiling points under atmospheric pressure of the one or more second solvents is T Hl +10° C. or less.
The lowest boiling point T Ll among the boiling points under atmospheric pressure of the one or more first solvents is T Lh −10° C. or higher.
The solvent may contain a sub-solvent in addition to the first solvent and the second solvent.
The solvent consists of a first solvent and a second solvent, or consists of a first solvent, a second solvent and a secondary solvent.
The boiling point of the secondary solvent under atmospheric pressure is less than (T Ll −10)° C., more than (T Lh +10)° C. and less than (T Hl −10)° C., or more than (T Hh +10)° C. for the external electrode. Paste.
　上記の通り、溶剤は、１種以上の第１溶剤と、１種以上の第２溶剤とを含む。外部電極用ペーストの調製の容易さの点で、第１溶剤は１種又は２種であるのが好ましく、１種であるのが好ましい。また、第２溶剤は１種又は２種であるのが好ましい。 As described above, the solvent includes one or more first solvents and one or more second solvents. From the viewpoint of ease of preparation of the external electrode paste, the number of first solvents is preferably one or two, preferably one. Moreover, it is preferable that the number of second solvents is one or two.
　溶剤の質量に対する、第１溶剤の質量の比率と、第２溶剤の質量の比率とが、それぞれ４０質量％以上である。外部電極用ペーストを塗工したときに、端部に比べて中央部が膨らむ形状となることを抑制しやすいことから、溶剤の質量に対する、第１溶剤の質量と第２溶剤の質量との合計の比率が９０質量％以上であるのが好ましく、９５質量％以上であるのがより好ましく、１００質量％であるのがさらに好ましい。 The ratio of the mass of the first solvent and the ratio of the mass of the second solvent to the mass of the solvent are each 40% by mass or more. When the external electrode paste is applied, it is easy to prevent the central portion from swelling compared to the end portions. is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 100% by mass.
　溶剤について、１種以上の第２溶剤の大気圧下での沸点のうち最も低い沸点ＴＨｌが、１種以上の第１溶剤の大気圧下での沸点のうち最も高い沸点ＴＬｈよりも１０℃以上高い。外部電極用ペーストが、このような沸点の差を満たす第２溶剤と第１溶剤とを含むことにより、外部電極用ペーストを塗工したときに、端部に比べて中央部が膨らむことを抑制しやすい。ＴＨｌは、ＴＬｈよりも２０℃以上高いのが好ましく、３０℃以上高いのがより好ましい。
　外部電極を形成する際に、溶剤を除去しやすい点から、ＴＨｌは、（ＴＬｈ＋１００）℃以下であるのが好ましく、（ＴＬｈ＋８０）℃以下であるのがより好ましく、（ＴＬｈ＋５０）℃以下であるのがさらに好ましい。 Regarding the solvent, the lowest atmospheric pressure boiling point T Hl of the one or more second solvents is 10 times higher than the highest atmospheric pressure boiling point T Lh of the one or more first solvent ℃ or higher. Since the external electrode paste contains the second solvent and the first solvent that satisfy such a difference in boiling point, swelling of the center portion compared to the end portions is suppressed when the external electrode paste is applied. It's easy to do. T Hl is preferably 20° C. or more higher than T Lh , more preferably 30° C. or more.
When forming the external electrodes, T Hl is preferably (T Lh +100) ° C. or less, more preferably (T Lh +80) ° C. or less, and (T Lh +50)°C or less is more preferable.
　第２溶剤を構成する１種以上の溶剤のそれぞれの大気圧下での沸点は、所望する効果が得られる限り特に限定されない。第２溶剤を構成する１種以上の溶剤のそれぞれの大気圧下での沸点は、２００℃以上３００℃以下が好ましく、２１０℃以上２５０℃以下がより好ましい。
　第１溶剤を構成する１種以上の溶剤のそれぞれの大気圧下での沸点は、所望する効果が得られる限り特に限定されない。第１溶剤を構成する１種以上の溶剤のそれぞれの大気圧下での沸点は、１５０℃以上２４０℃以下が好ましく、２００℃以上２３０℃以下がより好ましい。 The boiling point under atmospheric pressure of each of the one or more solvents constituting the second solvent is not particularly limited as long as the desired effect can be obtained. The boiling point under atmospheric pressure of the one or more solvents constituting the second solvent is preferably 200° C. or higher and 300° C. or lower, more preferably 210° C. or higher and 250° C. or lower.
The boiling point under atmospheric pressure of each of the one or more solvents constituting the first solvent is not particularly limited as long as the desired effect can be obtained. The boiling point under atmospheric pressure of the one or more solvents constituting the first solvent is preferably 150° C. or higher and 240° C. or lower, more preferably 200° C. or higher and 230° C. or lower.
　溶剤について、第２溶剤の表面張力の加重平均値と、第１溶剤の表面張力の加重平均値との差が３ｍＮ／ｍ以上であるのが好ましく、８ｍＮ／ｍ以上であるのがより好ましい。第１溶剤の表面張力と、第２溶剤の表面張力とは、どちらが高くてもよい。第２溶剤の表面張力の加重平均値と、第１溶剤の表面張力の加重平均値とが、上記の関係を満たす場合、外部電極用ペーストを塗工して膜を形成した際に、端部に比べて中央部が膨らむことを抑制しやすい。 Regarding the solvent, the difference between the weighted average value of the surface tension of the second solvent and the weighted average value of the surface tension of the first solvent is preferably 3 mN/m or more, more preferably 8 mN/m or more. Either the surface tension of the first solvent or the surface tension of the second solvent may be higher. When the weighted average value of the surface tension of the second solvent and the weighted average value of the surface tension of the first solvent satisfy the above relationship, when the external electrode paste is applied to form a film, the end portion It is easy to suppress swelling of the central portion compared to .
　第２溶剤の表面張力の加重平均値は、２３ｍＮ／ｍ以上５０ｍＮ／ｍ以下が好ましい。
　第１溶剤の表面張力の加重平均値は、２０ｍＮ／ｍ以上４７ｍＮ／ｍ以下が好ましい。 The weighted average value of the surface tension of the second solvent is preferably 23 mN/m or more and 50 mN/m or less.
The weighted average value of the surface tension of the first solvent is preferably 20 mN/m or more and 47 mN/m or less.
　外部電極用ペーストの質量に対する、溶剤の質量の比率は、３５質量％以上５０質量％以下が好ましく、３７．５質量％以上４５質量％以下がより好ましい。かかる範囲内の量の溶剤を用いることにより、外部電極用ペーストを用いて製膜する際に、外部電極用ペーストが良好に対流、流動し、外部電極用ペーストを塗工したときに、端部に比べて中央部が膨らむことを抑制しやすい。 The ratio of the solvent mass to the mass of the external electrode paste is preferably 35% by mass or more and 50% by mass or less, more preferably 37.5% by mass or more and 45% by mass or less. By using the solvent in an amount within such a range, the external electrode paste can convect and flow well when forming a film using the external electrode paste, and when the external electrode paste is applied, the end portion It is easy to suppress swelling of the central portion compared to .
　溶剤の好適な具体例としては、テキサノール、プロピレングリコールモノフェニルエーテル、ブチルカルビトール、テルペン系溶剤、ジエチレングリコール、カルビトールアセテート、ブチルカルビトールアセテート、ベンジルアルコール、メチルプロピレンジグリコール、ジフェニルエーテル、及びエチレングリコール等が挙げられる。 Preferred specific examples of solvents include texanol, propylene glycol monophenyl ether, butyl carbitol, terpene solvents, diethylene glycol, carbitol acetate, butyl carbitol acetate, benzyl alcohol, methylpropylene diglycol, diphenyl ether, ethylene glycol, and the like. is mentioned.
　所望する効果が得られる限りにおいて、外部電極用ペーストは、前述の樹脂、及び金属フィラーとともに、ガラスフリット、分散剤、増粘剤等の任意成分を含んでいてもよい。これらの任意成分は、外部電極用ペーストにおける通常の使用量を勘案して適宜使用される。 As long as the desired effect is obtained, the external electrode paste may contain optional components such as a glass frit, a dispersant, and a thickener along with the resin and metal filler described above. These optional components are appropriately used in consideration of the amount normally used in the external electrode paste.
　以上説明した、樹脂、及び金属フィラーと、必要に応じて上記の任意成分とを、所望する比率で上記の所定の要件を満たす溶剤中に、溶解、分散させることにより外部電極用ペーストが得られる。 The external electrode paste can be obtained by dissolving and dispersing the resins and metal fillers described above, and optionally the above-described optional components, in a desired ratio in a solvent that satisfies the above-described predetermined requirements. .
　以下、図１は、本実施形態における外部電極用ペースト１１を、セラミック素体１２に塗工する工程を説明するための図である。 FIG. 1 is a diagram for explaining the process of applying the external electrode paste 11 to the ceramic body 12 in this embodiment.
　初めに、セラミック素体１２の外部電極を形成する領域を外部電極用ペースト１１に浸漬する（図１（ａ）参照）。次いで、セラミック素体１２を、引き上げる（図１（ｂ）参照）。外部電極を形成する領域とは、例えば、セラミック素体１２の両端面である。ここでは、セラミック素体１２に付着した外部電極用ペーストの符号を１１ａとして説明する。外部電極用ペースト１１ａとして上述の外部電極用ペーストを用いる場合、セラミック素体１２を引き上げると、セラミック素体１２に付着した外部電極用ペースト１１ａの中央部と、端部との間の温度差や溶質の濃度差によって、図１（ｂ）の矢印で示すように、マランゴニ対流が生じる。なお、溶質は、外部電極用ペースト１１ａに含まれる樹脂である。 First, the regions where the external electrodes of the ceramic body 12 are to be formed are immersed in the external electrode paste 11 (see FIG. 1(a)). Next, the ceramic body 12 is pulled up (see FIG. 1(b)). The regions where the external electrodes are formed are, for example, both end faces of the ceramic body 12 . Here, the external electrode paste applied to the ceramic body 12 is denoted by 11a. When the above-mentioned external electrode paste is used as the external electrode paste 11a, when the ceramic body 12 is pulled up, the temperature difference between the central portion and the end portions of the external electrode paste 11a adhering to the ceramic body 12, and The solute concentration difference causes Marangoni convection, as indicated by the arrows in FIG. 1(b). The solute is the resin contained in the external electrode paste 11a.
　中央部と比べて端部における外部電極用ペーストの塗工量は少なく、端部における体積当たりの気液界面が大きい。このため、端部の方が乾燥が進みやすい。したがって、外部電極用ペースト中の固形分（樹脂及び金属フィラー）の割合は、中央部に比べて端部の方が多い。その結果、端部において、固液界面が中央部に対して相対的に増加することにより、端部がエネルギー的に不安定になる。また、溶剤の中でも、第１溶剤が優先的に揮発する。これらのため、外部電極用ペーストにおいて固形分の濃度勾配が緩和されるように中央部から端部に溶剤が移動する。また、溶剤の組成が均一化されるように、中央部から端部への溶剤の対流が生じる。その結果、中央部から端部へと外部電極用ペースト１１ａが流れる外向流が生じる（図１（ｃ）参照）。この外向流は、端部の樹脂濃度が中央部の樹脂濃度よりも高い間に、生じる。なお、乾燥が進むと、溶質と溶剤との界面が増える。このときの界面張力が大きいほど、エネルギー的に不安定であり、外向流が強くなると考えられる。 　Compared to the center part, the coating amount of the external electrode paste is smaller at the end part, and the gas-liquid interface per volume at the end part is larger. For this reason, drying progresses more easily at the ends. Therefore, the ratio of the solid content (resin and metal filler) in the external electrode paste is higher in the end portion than in the center portion. As a result, the solid-liquid interface increases at the edge relative to the center, making the edge energetically unstable. Moreover, among the solvents, the first solvent preferentially volatilizes. For these reasons, the solvent moves from the central portion to the end portions so that the concentration gradient of the solid content in the external electrode paste is relaxed. Also, convection of the solvent from the center to the ends is generated so that the composition of the solvent is homogenized. As a result, an outward flow is generated in which the external electrode paste 11a flows from the central portion to the end portions (see FIG. 1(c)). This outward flow occurs while the resin concentration at the edges is higher than that at the center. As the drying progresses, the interface between the solute and the solvent increases. It is considered that the greater the interfacial tension at this time, the more unstable the energy and the stronger the outward flow.
　ここで、前述の外部電極用ペーストを用いる場合、前述の通り、セラミック素体１２上の外部電極用ペースト１１ａが乾燥される過程において溶剤の組成が均一化されるように、溶剤の移動が生じる。この溶剤の移動は、外向流を助長する役割を果たす。強い外向流が生じることにより、中央部から端部へと外部電極用ペースト１１ａが流動する。このため、中央部において、外部電極用ペースト１１ａが外側に膨らむことを抑制することができる（図１（ｄ）参照）。 Here, when the above-described external electrode paste is used, as described above, the solvent moves so that the composition of the solvent becomes uniform during the process of drying the external electrode paste 11a on the ceramic body 12. . This solvent movement serves to promote outward flow. Due to the strong outward flow, the external electrode paste 11a flows from the central portion to the end portions. Therefore, it is possible to prevent the external electrode paste 11a from swelling outward in the central portion (see FIG. 1(d)).
　すなわち、本実施形態における外部電極用ペーストは、溶剤として、前述の第２溶剤と第１溶剤とを所定量含むので、従来の外部電極用ペーストとよりも流動性に優れる。その結果、本実施形態における外部電極用ペーストを用いると、端部に比べて中央部が膨らむことを抑制することができる。したがって、本実施形態における外部電極用ペーストを用いて作製される電子部品は、小型化される。 That is, the external electrode paste in the present embodiment contains predetermined amounts of the above-described second solvent and first solvent as solvents, and therefore has better fluidity than conventional external electrode pastes. As a result, the use of the external electrode paste according to the present embodiment can suppress swelling of the center portion compared to the end portions. Therefore, an electronic component manufactured using the external electrode paste in this embodiment is miniaturized.
　図２（ａ）は、セラミック素体２１ａに、本実施形態における外部電極用ペーストを用いて外部電極２２ａを形成した積層セラミックコンデンサ２０ａの断面を模式的に示す図である。また、図２（ｂ）は、セラミック素体２１ｂに、従来の外部電極用ペーストを用いて外部電極２２ｂを形成した積層セラミックコンデンサ２０ｂの断面を模式的に示す図である。 FIG. 2(a) is a diagram schematically showing a cross section of a multilayer ceramic capacitor 20a in which external electrodes 22a are formed on a ceramic body 21a using the external electrode paste of the present embodiment. FIG. 2(b) is a schematic cross-sectional view of a multilayer ceramic capacitor 20b in which external electrodes 22b are formed on a ceramic body 21b using a conventional external electrode paste.
　図２（ｂ）に示すように、従来の外部電極用ペーストを用いて形成される外部電極２２ｂの形状は、中央部が厚く、端部が薄い凸状の形状である。これに対して、本実施形態における外部電極用ペーストを用いて形成される外部電極２２ａの形状は、中央部のふくらみが抑制された平坦な形状である。したがって、本実施形態における外部電極用ペーストを用いて外部電極を形成することにより、積層セラミックコンデンサが、小型化すされ得る。また、同じサイズで比較した場合には、外部電極を薄くして内部素子を大きくすることができるので、大容量化することが可能となる。 As shown in FIG. 2(b), the shape of the external electrode 22b formed using the conventional external electrode paste is a convex shape with a thick central portion and thin end portions. On the other hand, the shape of the external electrode 22a formed using the external electrode paste in the present embodiment is a flat shape in which swelling at the central portion is suppressed. Therefore, by forming the external electrodes using the external electrode paste of the present embodiment, the size of the multilayer ceramic capacitor can be reduced. In addition, when compared with the same size, the external electrodes can be made thinner and the internal elements can be made larger, so that the capacity can be increased.
　なお、本実施形態における外部電極用ペーストをセラミック素体に塗工する方法が上述した外部電極用ペーストへの浸漬に限定されることはない。 It should be noted that the method of applying the external electrode paste to the ceramic body in this embodiment is not limited to the immersion in the external electrode paste described above.
　以上説明した外部電極用ペーストは、電子部品、例えば積層セラミックコンデンサの外部電極を形成する際に用いることができる。この外部電極用ペーストを用いて製造される電子部品は、電子部品素子を準備する工程と、電子部品素子の外表面に、本実施形態における外部電極用ペーストを付与する工程と、付与された外部電極用ペーストを焼き付けることによって外部電極を形成する工程と、を経て製造することができる。 The external electrode paste described above can be used when forming external electrodes of electronic components, such as multilayer ceramic capacitors. An electronic component manufactured using this external electrode paste includes the steps of preparing an electronic component element, applying the external electrode paste of the present embodiment to the outer surface of the electronic component element, and applying the applied external and a step of forming the external electrodes by baking the electrode paste.
　上述の外部電極用ペーストを付与する工程と、付与された外部電極用ペーストを焼き付ける工程との間に、外部電極用ペーストを乾燥させる工程が含まれていてもよい。 A step of drying the external electrode paste may be included between the step of applying the external electrode paste and the step of baking the applied external electrode paste.
　外部電極用ペーストを電子部品素子の外表面に付与する方法としては、印刷、ディッピング等種々の方法を適用することが可能である。 As a method of applying the external electrode paste to the outer surface of the electronic component element, various methods such as printing and dipping can be applied.
　電子部品素子は、例えば、セラミック層と、内部電極とが交互に複数積層された構造を有する。 An electronic component element has, for example, a structure in which a plurality of ceramic layers and internal electrodes are alternately laminated.
　以下、本発明を実施例によりさらに詳細に説明するが、本発明はこれらの実施例に限定されない。 Although the present invention will be described in more detail below with reference to examples, the present invention is not limited to these examples.
　実施例、及び比較例において、溶剤として以下の沸点、及び表面張力を有する溶剤Ｓ１～Ｓ５を用いた。なお、以下に記載した沸点は、大気圧下での沸点である。
Ｓ１：沸点２４４℃、表面張力２６ｍＮ／ｍ
Ｓ２：沸点２０５℃、表面張力４８ｍＮ／ｍ
Ｓ３：沸点２４４℃、表面張力２８ｍＮ／ｍ
Ｓ４：沸点２１８℃、表面張力３１ｍＮ／ｍ
Ｓ５：沸点２２０℃、表面張力２９ｍＮ／ｍ In Examples and Comparative Examples, solvents S1 to S5 having the following boiling points and surface tensions were used. In addition, the boiling point described below is a boiling point under atmospheric pressure.
S1: Boiling point 244°C, surface tension 26mN/m
S2: Boiling point 205°C, surface tension 48mN/m
S3: Boiling point 244°C, surface tension 28mN/m
S4: Boiling point 218°C, surface tension 31mN/m
S5: Boiling point 220°C, surface tension 29mN/m
　実施例１～８、実施例１０～１８、比較例１、及び比較例２において、表２に記載の平均径を有し、コート層を備える銅微粒子を金属フィラーとして用いた。実施例９において、表２に記載の平均径を有し、コート層を備えない同粒子を金属フィラーとして用いた。 In Examples 1 to 8, Examples 10 to 18, Comparative Examples 1, and 2, copper fine particles having the average diameter shown in Table 2 and provided with a coat layer were used as metal fillers. In Example 9, the same particles having the average diameter shown in Table 2 and having no coating layer were used as the metal filler.
　実施例１～７、実施例９～１８、比較例１、及び比較例２において、樹脂として、セルロース系樹脂を含む樹脂Ｒ１を用いた。実施例８において、セルロース系樹脂を含まない樹脂Ｒ２を用いた。 In Examples 1 to 7, Examples 9 to 18, Comparative Examples 1, and 2, resin R1 containing cellulose resin was used as the resin. In Example 8, resin R2 containing no cellulose resin was used.
　表２に記載の金属フィラー５０質量部と、表２に記載の種類の樹脂７質量部とを、表２に記載の固形分濃度となるように溶剤に溶解・分散させて、各実施例、及び各比較例の外部電極用ペーストを得た。
　実施例１～１８、及び比較例２では、それぞれ表１に記載の第１溶剤、及び第２溶剤が質量比１：１で混合された混合溶剤を溶剤として用いた。比較例１では、表１に記載のＳ５単独を溶剤として用いた。
　得られた外部電極用ペーストを用いて形成された膜の平坦性の評価と、得られた外部電極用ペーストを用いて形成された焼結後の膜の緻密性（ボイド抑制）の評価とを、下記の方法に従って行った。これらの評価結果を表２に記す。 50 parts by mass of the metal filler described in Table 2 and 7 parts by mass of the resin of the type described in Table 2 were dissolved and dispersed in a solvent so that the solid content concentration described in Table 2 was obtained. and pastes for external electrodes of respective comparative examples were obtained.
In Examples 1 to 18 and Comparative Example 2, a mixed solvent in which the first solvent and the second solvent shown in Table 1 were mixed at a mass ratio of 1:1 was used as the solvent. In Comparative Example 1, S5 alone described in Table 1 was used as the solvent.
An evaluation of the flatness of the film formed using the obtained external electrode paste and an evaluation of the compactness (void suppression) of the sintered film formed using the obtained external electrode paste were performed. , was carried out according to the following method. These evaluation results are shown in Table 2.
＜平坦性評価＞
　外部電極用ペーストを用いて形成される膜の平坦性を、以下の方法により確認した。まず、図４に示すような、長さ方向Ｌの寸法が１．０ｍｍ、幅方向Ｗの寸法が０．５ｍｍ、厚さ方向Ｔの寸法が０．５ｍｍのセラミック素体４０を用意した。このセラミック素体４０は、外部電極形成後に積層セラミックコンデンサを構成し、内部電極用ペーストが塗工されたセラミックグリーンシートが複数積層された積層体を焼成して形成された。セラミック素体４０の端面４１、及び端面４１と長さ方向Ｌの反対側に位置する端面には、内部電極４２が露出していた。 <Flatness evaluation>
The flatness of the film formed using the external electrode paste was confirmed by the following method. First, as shown in FIG. 4, a ceramic body 40 having a dimension in the length direction L of 1.0 mm, a dimension in the width direction W of 0.5 mm, and a dimension in the thickness direction T of 0.5 mm was prepared. This ceramic body 40 was formed by firing a laminated body in which a plurality of ceramic green sheets, which constitute a laminated ceramic capacitor after formation of external electrodes and were coated with paste for internal electrodes, were laminated. The internal electrodes 42 were exposed on the end face 41 of the ceramic body 40 and the end face located on the opposite side of the end face 41 in the length direction L. As shown in FIG.
　用意したセラミック素体４０の端面４１を外部電極用ペーストに浸漬した後、セラミック素体４０の端面４１とその周辺に塗工された外部電極用ペーストを乾燥させた。そして、図４に示すＡ－Ａ切断線、及びＢ－Ｂ切断線のそれぞれに沿ってセラミック素体４０を切断したときの外部電極用ペーストの膜厚の差を調べた。より具体的には、セラミック素体４０をＡ－Ａ切断線に沿って切断した位置における外部電極用ペーストの膜厚のうち、最も厚い部分の膜厚と、セラミック素体４０をＢ－Ｂ切断線に沿って切断した位置における外部電極用ペーストの膜厚のうち、最も薄い部分の膜厚との差を調べた。Ａ－Ａ切断線に沿って切断した位置における外部電極用ペーストを用いて形成された膜の厚さのうち、最も厚い部分の膜厚とは、厚さ方向Ｔの中央部の位置における膜厚である。また、Ｂ－Ｂ切断線に沿って切断した位置における外部電極用ペーストを用いて形成された膜の厚さのうち、最も薄い部分の膜厚とは、厚さ方向Ｔの端部における膜厚である。 After the end face 41 of the prepared ceramic body 40 was immersed in the external electrode paste, the external electrode paste applied to the end face 41 of the ceramic body 40 and its periphery was dried. Then, the difference in film thickness of the external electrode paste was examined when the ceramic body 40 was cut along the AA cutting line and the BB cutting line shown in FIG. More specifically, the thickness of the thickest part of the thickness of the external electrode paste at the position where the ceramic body 40 is cut along the AA cutting line, and the thickness of the ceramic body 40 at the BB cut The difference between the film thickness of the thinnest portion of the film thickness of the external electrode paste at the position cut along the line was examined. Of the thickness of the film formed using the external electrode paste at the position cut along the AA cutting line, the film thickness at the thickest portion is the film thickness at the central position in the thickness direction T. is. In addition, among the thicknesses of the film formed using the external electrode paste at the position cut along the BB cutting line, the film thickness at the thinnest portion is the film thickness at the end in the thickness direction T. is.
　ここで、Ａ－Ａ切断線は、セラミック素体４０の幅方向Ｗの中央の位置で、長さ方向Ｌ、及び厚さ方向Ｔで規定される面に沿って切断する際の切断線である。また、Ｂ－Ｂ切断線は、Ａ－Ａ切断線と平行な線であって、セラミック素体４０の幅方向Ｗにおける内部電極４２の端部の位置における切断線である。このＢ－Ｂ切断線の位置は、例えば、セラミック素体４０の幅方向の端部から幅方向Ｗに３０μｍ内側の位置である。 Here, the AA cutting line is the cutting line along the plane defined by the length direction L and the thickness direction T at the center position of the width direction W of the ceramic body 40. . Further, the BB cutting line is a line parallel to the AA cutting line and is a cutting line at the position of the end of the internal electrode 42 in the width direction W of the ceramic body 40 . The position of the BB cutting line is, for example, a position 30 μm inside in the width direction W from the end of the ceramic body 40 in the width direction.
　外部電極用ペーストを用いて形成された膜の厚さのうち、最も厚い部分の膜厚と、最も薄い部分の膜厚との差が３０μｍ以下であった場合を◎と判定した。前述の膜厚の差が３０μｍ超４０μｍ以下であった場合を○と判定した。前述の膜厚の差が４０μｍ超であった場合を×判定した。 A case where the difference between the thickness of the thickest portion and the thinnest portion of the film formed using the external electrode paste was 30 μm or less was judged as ⊚. A case where the difference in film thickness was more than 30 μm and 40 μm or less was determined as ◯. A case where the above-mentioned film thickness difference was more than 40 μm was evaluated as x.
＜緻密性（ボイド）評価＞
　各実施例、比較例の外部電極用ペーストを平坦性評価と同様にして製膜した後、得られた膜を窒素雰囲気下で最高温度７５０℃で焼結させた。
　焼結後の膜を、セラミック素体４０の端面４１に対して略垂直方向から、走査型電子顕微鏡（ＳＥＭ）により観察した。得られた観察画像から、焼結後の膜の面積に対するボイド部分の面積の比率を求めた。求められた、ボイド部分の面積の比率が１．６％未満であった場合を◎と判定した。ボイド部分の面積の比率が１．６％以上２．０％未満であった場合を○と判定した。ボイド部分の面積の比率が２．０％以上であった場合を×と判定した。 <Density (void) evaluation>
After the external electrode pastes of each example and comparative example were formed into films in the same manner as in the flatness evaluation, the obtained films were sintered at a maximum temperature of 750° C. in a nitrogen atmosphere.
The sintered film was observed with a scanning electron microscope (SEM) from a direction substantially perpendicular to the end surface 41 of the ceramic body 40 . From the observed image obtained, the ratio of the area of the void portion to the area of the film after sintering was obtained. A case in which the area ratio of void portions was less than 1.6% was evaluated as ⊚. A case where the ratio of the area of the void portion was 1.6% or more and less than 2.0% was evaluated as ◯. A case where the area ratio of the void portion was 2.0% or more was determined as x.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　実施例１～１８によれば、前述の所定の要件を満たすように第１溶剤と、第２溶剤とを組み合わせて含む外部電極用ペーストであれば、塗工したときに、端部に比べて中央部が膨らむ形状となることを抑制でき、塗工後の膜を焼結した際のボイドの発生を抑制できることが分かる。
　他方、比較例１及び比較例２によれば、外部電極用ペーストが、前述の所定の要件を満たすように第１溶剤と、第２溶剤とを組み合わせて含まない場合、塗工したときの、端部に比べて中央部が膨らむ形状となることの抑制と、塗工後の膜を焼結した際のボイドの発生の抑制とを両立できないことが分かる。 According to Examples 1 to 18, if the external electrode paste contains a combination of the first solvent and the second solvent so as to satisfy the above-described predetermined requirements, when it is applied, it is It can be seen that it is possible to suppress the central part from becoming swollen, and to suppress the generation of voids when the coated film is sintered.
On the other hand, according to Comparative Examples 1 and 2, when the external electrode paste does not contain a combination of the first solvent and the second solvent so as to satisfy the above-described predetermined requirements, when coated, It can be seen that it is not possible to simultaneously suppress the formation of a shape in which the center portion swells more than the end portions and suppress the generation of voids when the coated film is sintered.
１１　　外部電極用ペースト
１１ａ　セラミック素体に付着した外部電極用ペースト
１２　　セラミック素体
２０　　セラミック素体
２１　　端面
２２　　内部電極
３０ａ、３０ｂ　積層セラミックコンデンサ
３１ａ、３１ｂ　セラミック素体
３２ａ、３２ｂ　外部電極 11 External electrode paste 11a External electrode paste adhering to the ceramic body 12 Ceramic body 20 Ceramic body 21 End face 22 Internal electrodes 30a, 30b Multilayer ceramic capacitors 31a, 31b Ceramic body 32a, 32b External electrodes

Claims (10)

  1. 　樹脂と、
    　金属フィラーと、
    　溶剤と、
    を含み、
    　前記溶剤が、１種以上の第１溶剤と、１種以上の第２溶剤とを含み、
    　前記溶剤の質量に対する、前記第１溶剤の質量の比率と、前記第２溶剤の質量の比率とが、それぞれ４０質量％以上であり、
    　１種以上の前記第２溶剤の大気圧下での沸点のうち最も低い沸点ＴＨｌが、１種以上の前記第１溶剤の大気圧下での沸点のうち最も高い沸点ＴＬｈよりも１０℃以上高く、
    　１種以上の前記第２溶剤の大気圧下での沸点のうち最も高い沸点ＴＨｈが、ＴＨｌ＋１０℃以下であり、
    　１種以上の前記第１溶剤の大気圧下での沸点のうち最も低い沸点ＴＬｌが、ＴＬｈ－１０℃以上であり、
    　前記溶剤は、前記第１溶剤及び前記第２溶剤以外に副溶剤を含んでいてもよく、
    　前記副溶剤の大気圧下での沸点は、（ＴＬｌ－１０）℃未満、（ＴＬｈ＋１０）℃超（ＴＨｌ－１０）℃未満、又は（ＴＨｈ＋１０）℃超である、外部電極用ペースト。     a resin;
    a metal filler;
    a solvent;
    including
    the solvent comprises one or more first solvents and one or more second solvents,
    The ratio of the mass of the first solvent and the ratio of the mass of the second solvent to the mass of the solvent are each 40% by mass or more,
    The lowest boiling point T Hl among the boiling points under atmospheric pressure of the one or more second solvents is 10° C. higher than the highest boiling point T Lh among the boiling points under atmospheric pressure of the one or more first solvents higher than
    The highest boiling point T Hh among the boiling points under atmospheric pressure of the one or more second solvents is T Hl +10° C. or less,
    The lowest boiling point T Ll among the boiling points under atmospheric pressure of the one or more first solvents is T Lh −10° C. or higher,
    The solvent may contain a sub-solvent in addition to the first solvent and the second solvent,
    The external electrode, wherein the boiling point of the sub-solvent under atmospheric pressure is less than (T Ll −10)° C., more than (T Lh +10)° C. and less than (T Hl −10)° C., or more than (T Hh +10)° C. paste for.
  2. 　前記ＴＨｌが、前記ＴＬｈよりも２０℃以上高い、請求項１に記載の外部電極用ペースト。 The external electrode paste according to claim 1, wherein the T Hl is higher than the T Lh by 20°C or more.
  3. 　前記第１溶剤の表面張力の加重平均値と、前記第２溶剤の表面張力の加重平均値との差が、３ｍＮ／ｍ以上である、請求項１又は２に記載の外部電極用ペースト。 The external electrode paste according to claim 1 or 2, wherein the difference between the weighted average value of the surface tension of the first solvent and the weighted average value of the surface tension of the second solvent is 3 mN/m or more.
  4. 　前記第１溶剤の表面張力の加重平均値と、前記第２溶剤の表面張力の加重平均値との差が、８ｍＮ／ｍ以上である、請求項３に記載の外部電極用ペースト。 The external electrode paste according to claim 3, wherein the difference between the weighted average value of the surface tension of the first solvent and the weighted average value of the surface tension of the second solvent is 8 mN/m or more.
  5. 　前記樹脂が、セルロース系樹脂を含む、請求項１～４のいずれか１項に記載の外部電極用ペースト。 The external electrode paste according to any one of claims 1 to 4, wherein the resin contains a cellulose resin.
  6. 　前記金属フィラーが、その表面にコート層を備える、請求項１～５のいずれか１項に記載の外部電極用ペースト。 The external electrode paste according to any one of claims 1 to 5, wherein the metal filler has a coating layer on its surface.
  7. 　前記コート層が、前記金属フィラーの表面に付着又は結合したコート剤からなり、
    　前記コート剤が、シランカップリング剤、チタンカップリング剤、アルミニウムカップリング剤、脂肪族カルボン酸、脂肪族チオール、及びアミンカップリング剤からなる群より選択される１種以上である、請求項６に記載の外部電極用ペースト。     the coating layer is made of a coating agent adhered or bonded to the surface of the metal filler;
    Claim 6, wherein the coating agent is one or more selected from the group consisting of silane coupling agents, titanium coupling agents, aluminum coupling agents, aliphatic carboxylic acids, aliphatic thiols, and amine coupling agents. The external electrode paste described in .
  8. 　全外部電極用ペーストの質量に対する、前記溶剤の質量の比率が３５質量％以上５０質量％以下である、請求項１～７のいずれか１項に記載の外部電極用ペースト。 The external electrode paste according to any one of claims 1 to 7, wherein the ratio of the mass of the solvent to the mass of the entire external electrode paste is 35% by mass or more and 50% by mass or less.
  9. 　電子部品素子を準備する工程と、
    　電子部品素子の外表面に、請求項１～８のいずれか１項に記載の前記外部電極用ペーストを付与する工程と、
    　前記電子部品素子の外表面に付与された前記外部電極用ペーストを焼き付ける工程とを含む、電子部品における外部電極の形成方法。     A step of preparing an electronic component element;
    applying the external electrode paste according to any one of claims 1 to 8 to the outer surface of an electronic component element;
    and baking the external electrode paste applied to the outer surface of the electronic component element.
  10. 　請求項９に記載の外部電極の形成方法により外部電極を形成する工程を含む、電子部品の製造方法。 A method of manufacturing an electronic component, comprising the step of forming an external electrode by the method of forming an external electrode according to claim 9.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000286142A (en) * 1999-03-31 2000-10-13 Kyocera Corp Multilayer ceramic capacitor and external electrode paste
JP2002140934A (en) * 2000-08-24 2002-05-17 Murata Mfg Co Ltd Conductive paste and ceramic electronic component
JP2015124252A (en) * 2013-12-25 2015-07-06 株式会社ノリタケカンパニーリミテド Heat hardening conductive paste

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JP5715535B2 (en) 2011-09-27 2015-05-07 互応化学工業株式会社 Binder composition for firing

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000286142A (en) * 1999-03-31 2000-10-13 Kyocera Corp Multilayer ceramic capacitor and external electrode paste
JP2002140934A (en) * 2000-08-24 2002-05-17 Murata Mfg Co Ltd Conductive paste and ceramic electronic component
JP2015124252A (en) * 2013-12-25 2015-07-06 株式会社ノリタケカンパニーリミテド Heat hardening conductive paste

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