JP2018063997A - Chip capacitor and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chip capacitor having a bottom electrode which can be formed by a simple method, has low resistivity and excellent adhesion to a capacitor body and is highly reliable, and a method of manufacturing the chip capacitor.SOLUTION: The chip capacitor is provided that includes: a capacitor body in which a plurality of dielectric layers and internal electrode layers are alternately laminated; a bottom electrode electrically connected to the internal electrode layer of the capacitor body; and an external electrode provided on the bottom electrode. The bottom electrode includes a copper -containing metal phase and a glass phase containing phosphorus and oxygen.SELECTED DRAWING: None

Description

  The present invention relates to a chip capacitor and a manufacturing method thereof.

  In recent years, with the miniaturization, high integration, and high frequency of electric or electronic devices such as mobile phones, the demand for chip-type capacitor elements (chip capacitors) that are small and can be surface-mounted has increased rapidly.

  Among the chip capacitors, ceramic multilayer chip capacitors are produced every year due to the recent increase in demand for large-capacity products around the CPU (Central Processing Unit) and technological innovations for thinner and multilayered dielectric layers. Is expanding.

For the dielectric layer of the ceramic multilayer chip capacitor, a material mainly composed of barium titanate (BaTiO ₃ ), which is known to have a high dielectric constant, is generally used. When manufacturing a ceramic multilayer chip capacitor, first, a plurality of dielectric layer materials and internal electrode layer materials are alternately laminated to form a multilayer, and a ceramic green sheet laminate is obtained by pressing. Next, the ceramic green sheet laminate is cut into a predetermined size to form chips, and heat treatment (firing) is performed to obtain a laminate (hereinafter also referred to as “capacitor body”). Thereafter, in order to electrically connect the internal electrode layer of the capacitor body and the circuit board, external electrodes are formed on the capacitor body. This external electrode is usually formed by forming an electrode film of copper (Cu), nickel (Ni), tin (Sn), gold (Au), silver (Ag), etc. by electrolytic plating or the like. At this time, since the portion other than the internal electrode layer of the capacitor body is an insulator, a base electrode is formed in advance at a location where electrolytic plating is desired.

  Nickel (Ni) or copper (Cu) is mainly used for the internal electrode layer of ceramic multilayer chip capacitors. However, when nickel and copper are heat-treated (fired) in the atmosphere, they tend to increase in resistance due to oxidation. is there. For this reason, the heat treatment (firing) after the ceramic green sheet laminate is chipped is performed in a reducing atmosphere such as a mixed gas of hydrogen gas and nitrogen gas, for example. On the other hand, it is known that barium titanate becomes a semiconductor in a reducing atmosphere and causes a decrease in dielectric constant. Therefore, when barium titanate is used for the dielectric layer of the ceramic multilayer chip capacitor, a compound containing an element such as strontium (Sr), calcium (Ca), magnesium (Mg) is added in addition to barium titanate. There are many cases. By adding a compound containing an element such as strontium, a dielectric layer having both high insulating properties and high dielectric constant can be easily obtained even if heat treatment (firing) is performed in a reducing atmosphere.

  The base electrode is formed so as to be electrically connected to the internal electrode layer of the capacitor body. The base electrode is generally formed by applying a conductive composition containing conductive metal particles by printing or the like and heat-treating (sintering) the conductive composition. As the conductive metal particles, particles mainly composed of silver or copper are generally used for the purpose of lowering the volume resistivity (hereinafter also simply referred to as “resistivity”) of the underlying electrode to be formed. (For example, refer to Patent Documents 1 to 3).

Japanese Patent Laid-Open No. 10-208970 JP 2000-235828 A JP 2013-12688 A

  However, silver used for forming the base electrode is a noble metal and has limited resources, and the bullion itself is expensive. For this reason, the material which replaces a silver containing electroconductive composition (silver containing paste) is desired.

  On the other hand, the copper used to form the base electrode is abundant in terms of resources, and the price of the bare metal is about 1/100 that of silver. However, copper is easily oxidized in the air, and it is difficult to raise the temperature to 200 ° C. or higher when heat treatment (firing) is performed in the air. When heat treatment (firing) is performed at a temperature of 200 ° C. or higher, it is necessary to control the atmosphere such as lowering the oxygen concentration, and there is a problem that process costs are increased. For this reason, the copper containing electrode which can be formed in the state by which oxidation was suppressed also by the simple method is calculated | required. Furthermore, improvement in adhesion of the base electrode to the capacitor body is also required.

  The present invention has been made in view of the above circumstances, and is a chip capacitor that can be formed by a simple method, has low resistivity, excellent adhesion to the capacitor body, and has a highly reliable base electrode. It is another object of the present invention to provide a manufacturing method thereof.

Specific means for solving the above problems include the following embodiments.
<1> a capacitor body in which a plurality of dielectric layers and internal electrode layers are alternately stacked;
A base electrode electrically connected to the internal electrode layer of the capacitor body;
An external electrode provided on the base electrode,
The chip capacitor in which the base electrode includes a metal phase containing copper and a glass phase containing phosphorus and oxygen.

<2> The chip capacitor according to <1>, wherein the total content of metal and phosphorus in the base electrode is 45.0 mass% to 98.0 mass%.

<3> The chip capacitor according to <1> or <2>, wherein a phosphorus content in a total content of the metal and phosphorus in the base electrode is 2.0% by mass to 15.0% by mass.

<4> The chip capacitor according to any one of <1> to <3>, wherein the metal phase of the base electrode further contains tin.

<5> The chip capacitor according to any one of <1> to <4>, wherein the metal phase of the base electrode further contains nickel.

<6> The base electrode is at least one metal particle selected from the group consisting of phosphorus-containing copper alloy particles, phosphorus-tin-containing copper alloy particles, and phosphorus-tin-nickel-containing copper alloy particles, and glass particles. The chip capacitor according to any one of <1> to <5>, which is a heat-treated product of the composition for a base electrode containing

<7> The chip capacitor according to <6>, wherein the phosphorus-containing copper alloy particles have a phosphorus content of 2.0 mass% to 15.0 mass%.

<8> The chip capacitor according to <6> or <7>, wherein the phosphorus-tin-containing copper alloy particles have a phosphorus content of 2.0% by mass to 15.0% by mass.

<9> The chip capacitor according to any one of <6> to <8>, wherein the phosphorus-tin-containing copper alloy particles have a tin content of 3.0% by mass to 30.0% by mass.

<10> The chip capacitor according to any one of <6> to <9>, wherein the phosphorus-tin-nickel-containing copper alloy particles have a phosphorus content of 2.0 mass% to 15.0 mass%.

<11> The chip capacitor according to any one of <6> to <10>, wherein the phosphorus-tin-nickel-containing copper alloy particles have a tin content of 3.0 mass% to 30.0 mass%.

<12> The chip capacitor according to any one of <6> to <11>, wherein the phosphorus-tin-nickel-containing copper alloy particles have a nickel content of 3.0% by mass to 30.0% by mass.

<13> The chip capacitor according to any one of <6> to <12>, wherein the total content of the metal particles in the base electrode composition is 30.0 mass% to 94.0 mass%. .

<14> The chip capacitor according to any one of <6> to <13>, wherein the glass particle content in the base electrode composition is 0.1% by mass to 15.0% by mass.

<15> The chip capacitor according to any one of <6> to <14>, wherein the base electrode composition further contains a resin.

<16> The chip capacitor according to any one of <6> to <15>, wherein the composition for base electrode further contains a solvent.

<17> A capacitor main body in which a plurality of dielectric layers and internal electrode layers are alternately stacked, a base electrode electrically connected to the internal electrode layer of the capacitor main body, and an external provided on the base electrode An electrode, wherein the base electrode includes a metal phase containing copper and a glass phase containing phosphorus and oxygen,
Composition for ground electrode containing at least one metal particle selected from the group consisting of phosphorus-containing copper alloy particles, phosphorus-tin-containing copper alloy particles, and phosphorus-tin-nickel-containing copper alloy particles, and glass particles Applying to the capacitor body,
And a step of heat-treating the base electrode composition to form the base electrode.

  According to the present invention, it is possible to provide a chip capacitor having a base electrode that can be formed by a simple method, has low resistivity, has excellent adhesion to a capacitor body, and has high reliability, and a method for manufacturing the chip capacitor. it can.

It is a schematic sectional drawing which shows an example of the chip capacitor of this embodiment.

  Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments. In the following embodiments, the components (including element steps and the like) are not essential unless otherwise specified. The same applies to numerical values and ranges thereof, and the present invention is not limited thereto.

In the present specification, the numerical ranges indicated by using “to” include numerical values described before and after “to” as the minimum value and the maximum value, respectively.
In the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical range. Good. Further, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples.
In the present specification, the content of each component in the composition is the sum of the plurality of substances present in the composition unless there is a specific indication when there are a plurality of substances corresponding to each component in the composition. It means the content rate of.
In the present specification, the particle diameter of each component in the composition is a mixture of the plurality of types of particles present in the composition unless there is a specific indication when there are a plurality of types of particles corresponding to each component in the composition. Means the value of.
In this specification, the term “layer” or “film” refers to a part of the region in addition to the case where the layer or the film is formed when the region where the layer or film exists is observed. It is also included when it is formed only.
In this specification, the term “lamination” indicates that layers are stacked, and two or more layers may be combined, or two or more layers may be detachable.
In this specification, the term “process” includes a process that is independent of other processes and includes the process if the purpose of the process is achieved even if it cannot be clearly distinguished from the other processes. It is.

<Chip capacitor>
The chip capacitor of the present embodiment is provided on a capacitor body in which a plurality of dielectric layers and internal electrode layers are alternately stacked, a base electrode electrically connected to the internal electrode layer of the capacitor body, and the base electrode The base electrode includes a metal phase containing copper and a glass phase containing phosphorus and oxygen.

  A base electrode including a metal phase containing copper and a glass phase containing phosphorus and oxygen is not easily oxidized even when heat-treated (fired) in the air when forming the base electrode, and has a low resistivity. is there. In addition, the base electrode including the metal phase containing copper and the glass phase containing phosphorus and oxygen has excellent adhesion to the capacitor body and can provide a highly reliable chip capacitor.

  The total content of metal and phosphorus in the base electrode is, for example, preferably 45.0 mass% to 98.0 mass%, more preferably 50.0 mass% to 97.0 mass%, More preferably, it is 55.0 mass%-95.0 mass%. By setting the total content of metal and phosphorus to 45.0% by mass or more, voids in the base electrode tend to be effectively reduced and the internal electrode tends to be densified. On the other hand, when the total content of metal and phosphorus is 98.0% by mass or less, the base electrode has a lower resistivity and the adhesion to the capacitor body tends to be further improved.

  The copper content in the total content of metal and phosphorus in the base electrode is preferably 40.0 mass% to 98.0 mass%, for example, and preferably 45.0 mass% to 95.0 mass%. It is more preferable that it is 50.0 mass%-90.0 mass%. When the copper content in the total content of the metal and phosphorus in the base electrode is 40.0% by mass or more, a lower resistivity tends to be achieved. On the other hand, when the copper content in the total content of metal and phosphorus in the base electrode is 98.0% by mass or less, more excellent oxidation resistance tends to be achieved.

  The phosphorus content in the total content of the metal and phosphorus in the base electrode is, for example, 2.0% by mass to 15% from the viewpoint of lowering the resistivity of the base electrode and forming ability of the Cu—PO glass phase. It is preferably 0% by mass, more preferably 2.0% by mass to 8.3% by mass, further preferably 2.5% by mass to 8.0% by mass, and 3.0% by mass. It is especially preferable that it is -7.5 mass%. When the phosphorus content in the total content of the metal and phosphorus in the base electrode is 2.0% by mass or more, more excellent oxidation resistance tends to be achieved. On the other hand, when the phosphorus content in the total content of the metal and phosphorus in the base electrode is 15.0% by mass or less, a lower resistivity tends to be achieved.

  The metal phase of the base electrode may contain tin in addition to copper. When the metal phase contains tin, the tin content in the total content of the metal and phosphorus in the base electrode is, for example, from the viewpoint of lowering the resistivity of the base electrode and the ability to form the Sn—PO glass phase. 3.0 mass% to 30.0 mass%, preferably 3.5 mass% to 27.0 mass%, more preferably 4.0 mass% to 25.0 mass%. Is more preferable. When the tin content in the total content of the metal and phosphorus in the base electrode is 3.0% by mass or more, a Cu-Sn alloy phase can be effectively formed, and a better oxidation resistance can be achieved. It is in. On the other hand, when the tin content in the total content of the metal and phosphorus in the base electrode is 30.0% by mass or less, the ability to form a Sn—PO glass phase tends to be improved.

  The metal phase of the base electrode may contain nickel in addition to copper. When the metal phase contains nickel, the nickel content in the total content of the metal and phosphorus in the base electrode is, for example, 3.0% by mass to 30.0% from the viewpoint of reducing the resistivity of the base electrode. %, More preferably 3.5% by mass to 27.0% by mass, and still more preferably 4.0% by mass to 25.0% by mass. When the nickel content in the total content of the metal and phosphorus in the base electrode is 3.0% by mass or more, the Cu—Sn—Ni alloy phase and the Cu—Ni alloy phase can be effectively formed, and more excellent There is a tendency to achieve oxidation resistance. In addition, the nickel content in the total content of metal and phosphorus in the base electrode is 30.0% by mass or less, so that the Cu ratio in the base electrode is increased and the resistivity of the base electrode can be reduced. It is in.

  The content of each element constituting the internal electrode can be measured by quantitative analysis using an inductively coupled plasma mass spectrometry (ICP-MS) method or quantitative analysis using an energy dispersive X-ray spectroscopy (EDX) method.

  The base electrode contains at least one metal particle selected from the group consisting of phosphorus-containing copper alloy particles, phosphorus-tin-containing copper alloy particles, and phosphorus-tin-nickel-containing copper alloy particles, and glass particles. It is preferably a heat-treated (fired) product of the electrode composition. When the composition for base electrodes contains the above metal particles, oxidation of copper during heat treatment (firing) in the atmosphere is suppressed, and a base electrode having a lower resistivity can be formed. In addition, when the base electrode composition is applied to the capacitor body to form the base electrode, the adhesion of the formed base electrode to the capacitor body can be improved.

  An example of the chip capacitor of this embodiment is shown in the schematic cross-sectional view of FIG. FIG. 1 shows a simplified configuration of a chip capacitor, and the configuration of the present invention is not limited to this. Further, the size of the members in FIG. 1 is conceptual, and the relative relationship between the sizes of the members is not limited to this.

  A chip capacitor 1 shown in FIG. 1 includes a capacitor body 2 in which a plurality of dielectric layers 3 and internal electrode layers 4 are alternately stacked, and a base electrode 5 electrically connected to the internal electrode layer 4 of the capacitor body 2. And external electrodes 6 and 7 provided on the base electrode 5.

The capacitor body 2 is formed by alternately laminating a plurality of dielectric layers 3 and internal electrode layers 4. The plurality of internal electrode layers 4 include a first internal electrode layer that extends to one end face that intersects the stacking direction of the capacitor body 2, and a second internal electrode layer that extends to the other end face of the capacitor body 2. Are alternately stacked.
The base electrode 5 is provided at both ends of the capacitor body 2 so as to be in contact with the plurality of internal electrode layers 4 of the capacitor body 2, and is electrically connected to the internal electrode layer 4 at both ends. More specifically, the base electrode 5 is continuously provided from both end surfaces of the capacitor body 2 to the end portions of the four adjacent surfaces.
The external electrodes 6 and 7 are provided on the base electrode 5 in this order. The external electrode is not limited to the two-layer structure as shown in FIG. 1, and may be one layer or three or more layers.

  Below, the composition for base electrodes which can be used for manufacture of the chip capacitor of this embodiment will be described first, then the method for forming the base electrode will be described, and then the method for manufacturing the chip capacitor will be described.

<Composition for base electrode>
The composition for base electrodes comprises at least one metal particle selected from the group consisting of phosphorus-containing copper alloy particles, phosphorus-tin-containing copper alloy particles, and phosphorus-tin-nickel-containing copper alloy particles, and glass particles. contains. The composition for base electrodes may contain other components as necessary.

(Metal particles)
The composition for base electrodes contains at least one metal particle selected from the group consisting of phosphorus-containing copper alloy particles, phosphorus-tin-containing copper alloy particles, and phosphorus-tin-nickel-containing copper alloy particles.

  The total content of the metal particles in the base electrode composition is, for example, preferably 30.0% by mass to 94.0% by mass, and more preferably 35.0% by mass to 90.0% by mass. Preferably, it is 40.0 mass%-85.0 mass%. By setting the total content of the metal particles to 30.0% by mass or more, voids in the base electrode tend to be effectively reduced and the base electrode tends to be densified. On the other hand, when the total content of the metal particles is 94.0% by mass or less, the workability when applied to the capacitor body is improved, the base electrode has a lower resistivity, and the adhesion to the capacitor body is more improved. It tends to improve.

[Phosphorus-containing copper alloy particles]
The composition for base electrodes may contain phosphorus-containing copper alloy particles as metal particles. As a phosphorus-containing copper alloy, a brazing material called phosphorus copper brazing (phosphorus concentration: about 7% by mass or less) is known. Phosphor copper brazing is also used as a bonding agent between copper and copper. By using phosphorus-containing copper alloy particles in the base electrode composition, it is possible to form a base electrode having excellent oxidation resistance and low resistivity by utilizing the reducibility of phosphorus to copper oxide.

Moreover, in addition to forming the reduced copper metal phase by including the phosphorus-containing copper alloy particles as the metal particles in the base electrode composition, a glass phase containing phosphorus and oxygen during heat treatment (firing) ( By forming a Cu—P—O glass phase or the like, the adhesion of the base electrode to the capacitor body can be improved. This can be considered as follows, for example.
When the composition for base electrodes containing phosphorus-containing copper alloy particles is used, a mixed structure of copper (Cu phase) and copper phosphide (Cu ₃ P phase) in which phosphorus is dissolved is formed in the metal structure. The At this time, the Cu phase is oxidized to form copper oxide (Cu ₂ O phase) in a relatively low temperature region around 200 ° C. in the heat treatment (firing) in the atmosphere, but the heating temperature is raised to around 420 ° C. The Cu ₃ P phase is oxidized to form a Cu—P—O glass phase, while the Cu ₂ O phase is reduced again to copper. The presence of this glass phase is thought to improve the adhesion of the base electrode to the capacitor body.

  The phosphorus content of the phosphorus-containing copper alloy particles is, for example, 2.0% by mass to 15.0% by mass from the viewpoint of lowering the resistivity of the base electrode and forming ability of the Cu—PO glass phase. Preferably, it is 2.0% by mass to 8.3% by mass, more preferably 2.5% by mass to 8.0% by mass, and 3.0% by mass to 7.5% by mass. It is particularly preferred. It exists in the tendency which can achieve more superior oxidation resistance because the phosphorus content rate of phosphorus containing copper alloy particle | grains is 2.0 mass% or more. On the other hand, when the phosphorus content of the phosphorus-containing copper alloy particles is 15.0% by mass or less, a lower resistivity tends to be achieved.

The phosphorus-containing copper alloy particles may further contain other atoms inevitably mixed in addition to phosphorus and copper. Examples of other atoms include Ag, Sb, Si, K, Na, Li, Ba, Sr, Ca, Mg, Be, Zn, Pb, Cd, Tl, V, Al, Zr, W, Mo, Ti, Mention may be made of Co and Au.
The content of other atoms contained in the phosphorus-containing copper alloy particles can be, for example, 1.0% by mass or less in the phosphorus-containing copper alloy particles, and the viewpoint of oxidation resistance and lower resistivity of the base electrode Therefore, the content is preferably 0.5% by mass or less.

  In addition, the content rate of each element in the phosphorus containing copper alloy particle | grains which comprise phosphorus containing copper alloy particle | grains is the quantitative analysis of an inductively coupled plasma mass spectrometry (ICP-MS) method, or the quantitative analysis of an energy dispersive X-ray spectroscopy (EDX) method. Can be measured.

  The particle diameter of the phosphorus-containing copper alloy particles is not particularly limited. In the particle size distribution, the particle diameter (hereinafter sometimes abbreviated as “D50%”) when the volume integrated from the small diameter side is 50% is preferably 0.4 μm to 10 μm, for example, and preferably 1 μm to 7 μm. It is more preferable that By setting D50% of the phosphorus-containing copper alloy particles to 0.4 μm or more, the oxidation resistance tends to be further improved. On the other hand, when the D50% of the phosphorus-containing copper alloy particles is 10 μm or less, the contact area between the metal particles containing the phosphorus-containing copper alloy particles in the base electrode increases, and the resistivity of the base electrode tends to decrease more. It is in.

  The particle size of the phosphorus-containing copper alloy particles is measured by a laser diffraction particle size distribution analyzer (for example, Beckman Coulter, Inc., LS 13 320 type laser scattering diffraction particle size distribution analyzer). Specifically, phosphorus-containing copper alloy particles are added to 125 g of a solvent (terpineol) within a range of 0.01% by mass to 0.3% by mass to prepare a dispersion. About 100 mL of this dispersion is injected into the cell and measured at 25 ° C. The particle size distribution is measured with the refractive index of the solvent being 1.48.

  The shape of the phosphorus-containing copper alloy particles is not particularly limited, and may be any of a substantially spherical shape, a flat shape, a block shape, a plate shape, a scale shape, and the like. From the standpoint of oxidation resistance and lowering the resistivity of the base electrode, the shape of the phosphorus-containing copper alloy particles is preferably substantially spherical, flat, or plate-like.

The phosphorus-containing copper alloy can be produced by a commonly used method. Moreover, phosphorus containing copper alloy particle | grains can be prepared using the normal method of preparing a metal particle using the phosphorus containing copper alloy prepared so that it might become a desired phosphorus content rate. For example, it can be manufactured by a conventional method using a water atomizing method. Details of the water atomization method are described in Metal Manual (Maruzen Co., Ltd. Publishing Division).
Specifically, the desired phosphorus-containing copper alloy particles can be produced by melting the phosphorus-containing copper alloy, making it into particles by nozzle spraying, and drying and classifying the obtained particles. Moreover, the phosphorus containing copper alloy particle | grains which have a desired particle diameter can be manufactured by selecting classification conditions suitably.

  Phosphorus-containing copper alloy particles may be used alone or in combination of two or more. As an aspect of using two or more types of phosphorus-containing copper alloy particles in combination, for example, two or more types of phosphorus-containing copper alloy particles having the same particle shape, such as particle diameter and particle size distribution, with different component ratios are used in combination. An embodiment in which two or more types of phosphorus-containing copper alloy particles having the same aspect ratio but different particle shapes are used in combination, and two or more types of phosphorus-containing copper alloy particles having different component ratios and particle shapes are used in combination. An embodiment is mentioned.

  When the base electrode composition contains phosphorus-containing copper alloy particles, the content is not particularly limited. From the viewpoint of oxidation resistance and lower resistivity of the base electrode, the content of the phosphorus-containing copper alloy particles in the base electrode composition is preferably, for example, 30.0 mass% to 94.0 mass%. It is more preferably 35.0% by mass to 90.0% by mass, and further preferably 40.0% by mass to 85.0% by mass.

[Phosphorus-tin-containing copper alloy particles]
The composition for base electrodes may contain phosphorus-tin-containing copper alloy particles as metal particles. By using phosphorus-tin-containing copper alloy particles in the base electrode composition, there is a tendency that a lower base electrode with lower resistivity and better adhesion to the capacitor body can be formed.

  This can be considered as follows, for example. When the phosphorus-tin-containing copper alloy particles are heat-treated (fired), phosphorus, tin, and copper in the phosphorus-tin-containing copper alloy particles react with each other to form a Cu phase, a Cu—Sn alloy phase, and a Sn—P—O. A glass phase is formed. When the Cu-Sn alloy phase is formed, the melting point of the alloy is reduced due to the eutectic reaction, and the sinterability of the base electrode is improved as compared with the case where the Cu phase is formed alone, resulting in a lower resistivity. Can be made.

  The Sn—PO glass phase formed by heat treatment (firing) of the phosphorus-tin-containing copper alloy particles is between the Cu phase and the Cu—Sn alloy phase, and between the Cu phase and the Cu—Sn alloy phase and the capacitor body. Exists at the interface. This further improves the strength of the base electrode itself and the adhesion between the base electrode and the capacitor body.

  The phosphorus content of the phosphorus-tin-containing copper alloy particles is, for example, 2.0% by mass to 15.0% by mass from the viewpoints of lowering the resistivity of the base electrode and forming ability of the Sn—PO glass phase. It is preferably 2.5% by mass to 12.0% by mass, more preferably 3.0% by mass to 10.5% by mass. It exists in the tendency which can achieve more superior oxidation resistance because the phosphorus content rate of a phosphorus- tin containing copper alloy particle is 2.0 mass% or more. On the other hand, when the phosphorus content of the phosphorus-tin-containing copper alloy particles is 15.0% by mass or less, a lower resistivity can be achieved, and the forming ability of the Sn—PO glass phase tends to be improved. is there.

  The tin content of the phosphorus-tin-containing copper alloy particles is, for example, 3.0% by mass to 30.0% by mass from the viewpoints of lowering the resistivity of the base electrode and forming ability of the Sn—PO glass phase. It is preferably 3.5% by mass to 27.0% by mass, more preferably 4.0% by mass to 25.0% by mass. When the tin content of the phosphorus-tin-containing copper alloy particles is 3.0% by mass or more, the Cu-Sn alloy phase can be effectively formed and more excellent oxidation resistance tends to be achieved. On the other hand, when the tin content of the phosphorus-tin-containing copper alloy particles is 30.0% by mass or less, the forming ability of the Sn—PO glass phase tends to be improved.

The phosphorus-tin-containing copper alloy particles may further contain other atoms inevitably mixed in addition to phosphorus, tin, and copper. Examples of other atoms include Ag, Sb, Si, K, Na, Li, Ba, Sr, Ca, Mg, Be, Zn, Pb, Cd, Tl, V, Al, Zr, W, Mo, Ti, Mention may be made of Co and Au.
The content of other atoms contained in the phosphorus-tin-containing copper alloy particles can be, for example, 1.0% by mass or less in the phosphorus-tin-containing copper alloy particles, and the oxidation resistance and the low resistance of the base electrode From the viewpoint of efficiency, it is preferably 0.5% by mass or less.

  The content of each element in the phosphorus-tin-containing copper alloy constituting the phosphorus-tin-containing copper alloy particles is determined by quantitative analysis by inductively coupled plasma mass spectrometry (ICP-MS) or energy dispersive X-ray spectroscopy (EDX). It can be measured by quantitative analysis of the method.

  The particle diameter of the phosphorus-tin-containing copper alloy particles is not particularly limited. The D50% of the phosphorus-tin-containing copper alloy particles is, for example, preferably 0.4 μm to 10 μm, and more preferably 1 μm to 7 μm. By setting D50% of the phosphorus-tin-containing copper alloy particles to 0.4 μm or more, the oxidation resistance tends to be further improved. On the other hand, by setting D50% of the phosphorus-tin-containing copper alloy particles to 10 μm or less, the contact area between the metal particles including the phosphorus-tin-containing copper alloy particles in the base electrode is increased, and the resistivity of the base electrode is increased. It tends to be lower.

  In addition, the measuring method of the particle diameter (D50%) of phosphorus- tin containing copper alloy particles is the same as the measuring method of the particle diameter of phosphorus containing copper alloy particles.

  The shape of the phosphorus-tin-containing copper alloy particles is not particularly limited, and may be any of a substantially spherical shape, a flat shape, a block shape, a plate shape, a scale shape, and the like. From the viewpoint of oxidation resistance and lowering the resistivity of the base electrode, the shape of the phosphorus-tin-containing copper alloy particles is preferably substantially spherical, flat or plate-like.

  The phosphorus-tin-containing copper alloy particles can be produced by a conventional method using a water atomizing method, similarly to the phosphorus-containing copper alloy particles.

  Phosphorus-tin-containing copper alloy particles may be used alone or in combination of two or more. For example, two or more types of phosphorus-tin-containing copper alloy particles may be used in combination of two or more types of phosphorus-tin-containing copper alloy particles. A mode in which two or more types of phosphorus-tin-containing copper alloy particles having the same particle ratio but different particle shapes are used in combination, and two or more types of phosphorus-tin in which the component ratio and particle shape are both different The aspect using combining copper alloy particle | grains is mentioned.

  When the composition for base electrodes contains phosphorus-tin-containing copper alloy particles, the content is not particularly limited. From the viewpoint of oxidation resistance and lower resistivity of the base electrode, the content of the phosphorus-tin-containing copper alloy particles in the base electrode composition is, for example, 30.0 mass% to 94.0 mass%. Is more preferably 35.0% by mass to 90.0% by mass, and still more preferably 40.0% by mass to 85.0% by mass.

[Phosphorus-tin-nickel-containing copper alloy particles]
The composition for base electrodes may contain phosphorus-tin-nickel-containing copper alloy particles as metal particles. By using phosphorus-tin-nickel-containing copper alloy particles in the composition for the base electrode, the resistivity is lower, and it is likely that an excellent base electrode can be formed with better adhesion to the capacitor body.

This can be considered as follows, for example. When the phosphorus-tin-nickel-containing copper alloy particles are heat-treated (fired), phosphorus, tin, nickel, and copper in the phosphorus-tin-nickel-containing copper alloy particles react with each other during the heat-treatment (firing) to form a Cu phase, A Cu-Ni alloy phase, a Cu-Sn-Ni alloy phase, and a Sn-PO glass phase are formed.
Here, it is considered that the Cu—Sn alloy phase is produced at a relatively low temperature of about 500 ° C., and the formed Cu—Sn alloy phase and nickel further react to form a Cu—Sn—Ni alloy phase. It is done. This Cu—Sn—Ni alloy phase may be formed even at a high temperature of 500 ° C. or higher (for example, 800 ° C.). Moreover, in connection with this, the tin concentration of a metal phase may reduce and a Cu-Ni alloy phase and Cu phase may be formed partially. As a result, it is possible to form a base electrode having a low resistivity while maintaining oxidation resistance even at higher temperature heat treatment (firing).

  Further, the Sn—PO glass phase formed in the heat treatment (firing) step of the phosphorus-tin-nickel-containing copper alloy particles is similar to the case of using the phosphorus-tin-containing copper alloy particles. And tin react with each other. The Sn—P—O glass phase is between the Cu—Sn—Ni alloy phase, the Cu—Ni alloy phase, and the Cu phase, and the Cu—Sn—Ni alloy phase, the Cu—Ni alloy phase, and the Cu phase and capacitor. By being present at the interface with the main body, the strength of the base electrode itself and the adhesion between the base electrode and the capacitor body are improved.

  The phosphorus content of the phosphorus-tin-nickel-containing copper alloy particles is, for example, 2.0% by mass to 15.0% by mass from the viewpoint of lowering the resistivity of the base electrode and the ability to form the Sn—PO glass layer. It is preferable that it is 2.5 mass%-12.0 mass%, and it is still more preferable that it is 3.0 mass%-10.5 mass%. It exists in the tendency which can achieve more superior oxidation resistance because the phosphorus content rate of a phosphorus- tin- nickel containing copper alloy particle is 2.0 mass% or more. On the other hand, when the phosphorus content of the phosphorus-tin-nickel-containing copper alloy particles is 15.0% by mass or less, a lower resistivity can be achieved, and the ability to form a Sn—PO glass phase is improved. There is a tendency.

  The tin content of the phosphorus-tin-nickel-containing copper alloy particles is, for example, from 3.0% by mass to 30.0% by mass from the viewpoint of lowering the resistivity of the base electrode and forming ability of the Sn—PO glass phase. It is preferable that it is 3.5 mass%-27.0 mass%, and it is still more preferable that it is 4.0 mass%-25.0 mass%. When the tin content of the phosphorus-tin-nickel-containing copper alloy particles is 3.0% by mass or more, a Cu-Sn-Ni alloy phase can be effectively formed and more excellent oxidation resistance can be achieved. is there. On the other hand, when the tin content of the phosphorus-tin-nickel-containing copper alloy particles is 30.0% by mass or less, the ability to form a Sn—PO glass phase tends to be improved.

  The nickel content of the phosphorus-tin-nickel-containing copper alloy particles is preferably 3.0% by mass to 30.0% by mass, for example, from the viewpoint of reducing the resistivity of the base electrode, and is 3.5% by mass. It is more preferably ˜27.0% by mass, and further preferably 4.0% by mass to 25.0% by mass. When the nickel content of the phosphorus-tin-nickel-containing copper alloy particles is 3.0% by mass or more, the Cu-Sn-Ni alloy phase and the Cu-Ni alloy phase can be effectively formed, and more excellent oxidation resistance. Tend to achieve sex. Moreover, when the nickel content of the phosphorus-tin-nickel-containing copper alloy particles is 30.0% by mass or less, the Cu ratio in the base electrode is increased, and the resistivity of the base electrode tends to be reduced. .

The phosphorus-tin-nickel-containing copper alloy particles may further contain other atoms inevitably mixed in addition to phosphorus, tin, nickel, and copper. Examples of other atoms include Ag, Sb, Si, K, Na, Li, Ba, Sr, Ca, Mg, Be, Zn, Pb, Cd, Tl, V, Al, Zr, W, Mo, Ti, Mention may be made of Co and Au.
The content of other atoms contained in the phosphorus-tin-nickel-containing copper alloy particles can be, for example, 1.0% by mass or less in the phosphorus-tin-nickel-containing copper alloy particles, and the oxidation resistance and base From the viewpoint of reducing the resistivity of the electrode, it is preferably 0.5% by mass or less.

  In addition, the content rate of each element in the phosphorus-tin-nickel-containing copper alloy constituting the phosphorus-tin-nickel-containing copper alloy particles is determined by quantitative analysis by inductively coupled plasma mass spectrometry (ICP-MS) method or energy dispersive X-ray. It can be measured by spectroscopic (EDX) quantitative analysis.

  The particle diameter of the phosphorus-tin-nickel-containing copper alloy particles is not particularly limited. The D50% of the phosphorus-tin-containing copper alloy particles is, for example, preferably 0.4 μm to 10 μm, and more preferably 1 μm to 7 μm. By setting D50% of the phosphorus-tin-nickel-containing copper alloy particles to 0.4 μm or more, the oxidation resistance tends to be further improved. On the other hand, by setting D50% of the phosphorus-tin-nickel-containing copper alloy particles to 10 μm or less, the contact area between the metal particles containing the phosphorus-tin-nickel-containing copper alloy particles in the base electrode increases, and the base electrode There is a tendency for the resistivity of the to decrease.

  In addition, the measuring method of the particle diameter (D50%) of phosphorus- tin- nickel containing copper alloy particle is the same as the measuring method of the particle diameter of phosphorus containing copper alloy particle.

  The shape of the phosphorus-tin-nickel-containing copper alloy particles is not particularly limited, and may be any of a substantially spherical shape, a flat shape, a block shape, a plate shape, a scale shape, and the like. From the viewpoint of oxidation resistance and lowering the resistivity of the base electrode, the shape of the phosphorus-tin-nickel-containing copper alloy particles is preferably substantially spherical, flat, or plate-like.

  The phosphorus-tin-nickel-containing copper alloy particles can be produced by a conventional method using a water atomization method, similarly to the phosphorus-containing copper alloy particles and the phosphorus-tin-containing copper alloy particles.

  Phosphorus-tin-nickel-containing copper alloy particles may be used alone or in combination of two or more. As an aspect of using two or more types of phosphorus-tin-nickel-containing copper alloy particles in combination, two or more types of phosphorus-tin-nickel-containing copper having the same particle shape such as particle diameter and particle size distribution, although the component ratios are different. An embodiment using a combination of alloy particles, an embodiment using a combination of two or more types of phosphorus-tin-nickel-containing copper alloy particles having the same component ratio but different particle shapes, and two or more types using both component ratios and particle shapes An embodiment in which the phosphorus-tin-nickel-containing copper alloy particles are used in combination.

  When the composition for base electrodes contains phosphorus-tin-nickel-containing copper alloy particles, the content is not particularly limited. From the standpoint of oxidation resistance and lower resistivity of the base electrode, the content of the phosphorus-tin-nickel-containing copper alloy particles in the base electrode composition is, for example, 30.0 mass% to 94.0 mass%. It is preferably 35.0% by mass to 90.0% by mass, more preferably 40.0% by mass to 85.0% by mass.

(Glass particles)
The composition for base electrodes contains at least one glass particle. Here, the glass particles mean those obtained by forming glass (amorphous solid exhibiting a glass transition phenomenon) into particles. When the composition for base electrode contains glass particles, the adhesion between the formed base electrode and the capacitor body is improved.

  The glass particles preferably have a softening point of 650 ° C. or lower from the viewpoint of lowering the resistivity of the base electrode and the adhesion between the base electrode and the capacitor body. When the softening point of the glass particles is 650 ° C. or less, the softened (melted) glass particles effectively cover the metal particles, and the reaction of the metal particles tends to be effectively expressed. That is, a metal phase containing copper and a glass phase containing phosphorus and oxygen are effectively formed, the resistivity of the base electrode is further lowered, and the adhesion between the base electrode and the capacitor body is further improved. There is a tendency.

  In addition, it is thought that the adhesion of the base electrode is improved by melting the glass particles and the melt uniformly covering the surface of the capacitor body. However, if the composition for the base electrode is used, during the heat treatment (firing) Further, since the glass phase is also generated from the metal particles, the adhesion between the base electrode and the capacitor body can be further improved as a result.

  From the viewpoint of reaction between metal particles such as phosphorus-containing copper alloy particles and sintering properties, and a glass phase forming ability derived from metal particles, the softening point of the glass particles is more preferably 550 ° C. or less, and 500 ° C. or less. More preferably it is. The softening point of the glass particles is measured by a usual method using a differential thermal-thermogravimetric analyzer (TG-DTA).

Examples of the glass component constituting the glass particles include silicon oxide (SiO or SiO ₂ ), phosphorus oxide (P ₂ O ₅ ), aluminum oxide (Al ₂ O ₃ ), boron oxide (B ₂ O ₃ ), and vanadium oxide. (V ₂ O ₅ ), potassium oxide (K ₂ O), bismuth oxide (Bi ₂ O ₃ ), sodium oxide (Na ₂ O), lithium oxide (Li ₂ O), barium oxide (BaO), strontium oxide (SrO) ), Calcium oxide (CaO), magnesium oxide (MgO), beryllium oxide (BeO), zinc oxide (ZnO), lead oxide (PbO), cadmium oxide (CdO), tin oxide (SnO), zirconium oxide (ZrO ₂ ) , tungsten oxide _(WO 3), molybdenum oxide _(MoO 3), lanthanum oxide _{(La 2 O} 3), niobium oxide (N ₂ O _5), tantalum oxide _{(Ta 2 O} 5), yttrium oxide _{(Y 2 O} 3), titanium oxide _(TiO 2), germanium oxide _(GeO 2), tellurium oxide _(TeO 2), lutetium oxide _(Lu 2 O ₃ ), antimony oxide (Sb ₂ O ₃ ), copper oxide (CuO), iron oxide (FeO, Fe ₂ O ₃ , or Fe ₃ O ₄ ), silver oxide (AgO or Ag ₂ O), and manganese oxide (MnO) ). In addition, in this specification, all the glass components which comprise a glass particle are described with an oxide.

Among them, glass particles containing at least one selected from the group consisting of SiO ₂ , P ₂ O ₅ , Al ₂ O ₃ , B ₂ O ₃ , V ₂ O ₅ , Bi ₂ O ₃ , ZnO, and PbO are used. It is preferable to use glass particles containing at least one selected from the group consisting of SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , Bi ₂ O ₃ , and PbO. In the case of such glass particles, the softening point tends to decrease more effectively. In addition, since such glass particles have improved wettability with metal particles, sintering between the metal particles during heat treatment (firing) proceeds, and it is likely that a lower electrode having a lower resistivity can be formed. .

  The particle diameter of the glass particles is not particularly limited. The D50% of the glass particles is preferably 0.5 μm to 10 μm, for example, and more preferably 0.8 μm to 8 μm. When the D50% of the glass particles is 0.5 μm or more, workability when preparing the composition for the base electrode tends to be improved. On the other hand, when the D50% of the glass particles is 10 μm or less, the glass particles are more uniformly dispersed in the composition for the base electrode, and the adhesion between the base electrode and the capacitor body tends to be further improved.

  In addition, the measuring method of the particle diameter (D50%) of a glass particle is the same as the measuring method of the particle diameter of phosphorus containing copper alloy particle.

  The shape of the glass particles is not particularly limited, and may be any of a substantially spherical shape, a flat shape, a block shape, a plate shape, a scale shape, and the like. From the viewpoint of oxidation resistance and lower resistivity of the base electrode, the shape of the glass particles is preferably substantially spherical, flat, or plate-like.

  The glass particle content in the base electrode composition is, for example, preferably 0.1% by mass to 15.0% by mass, and more preferably 0.5% by mass to 12.0% by mass. 1.0 mass% to 10.0 mass% is more preferable. By containing glass particles in such a range of content, oxidation resistance and lower resistivity of the base electrode tend to be achieved more effectively. Furthermore, it exists in the tendency which can promote the contact and reaction between metal particles.

(Solvent and resin)
The composition for base electrodes may contain at least one selected from the group consisting of a solvent and a resin. By containing at least one selected from the group consisting of a solvent and a resin, the liquid physical properties (viscosity, surface tension, etc.) of the composition for the base electrode are within a range suitable for the application method when applying to the capacitor body. Can be adjusted.

  The solvent is not particularly limited. Solvents include hydrocarbon solvents such as hexane, cyclohexane and toluene, halogenated hydrocarbon solvents such as dichloroethylene, dichloroethane and dichlorobenzene, and cyclics such as tetrahydrofuran, furan, tetrahydropyran, pyran, dioxane, 1,3-dioxolane and trioxane. Ether solvents, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, sulfoxide solvents such as dimethyl sulfoxide, diethyl sulfoxide, ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, cyclohexanone, ethanol, 2-propanol, Alcohol solvents such as 1-butanol and diacetone alcohol, 2,2,4-trimethyl-1,3-pentanediol monoacetate, 2,2,4-trimethyl-1,3- Nantanediol monopropionate, 2,2,4-trimethyl-1,3-pentanediol monobutyrate, ester solvents of polyhydric alcohols such as ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, butyl cellosolve, diethylene glycol mono Examples include ether solvents of polyhydric alcohols such as butyl ether and diethylene glycol diethyl ether, and terpene solvents such as terpinene, terpineol, myrcene, alloocimene, limonene, dipentene, pinene, carvone, osmene, and ferrandrene. A solvent may be used individually by 1 type and may be used in combination of 2 or more type.

  As the solvent, from the viewpoint of application characteristics (coating property and printability) when applying the composition for the base electrode to the capacitor body, for example, an ester solvent of polyhydric alcohol, a terpene solvent, and an ether solvent of polyhydric alcohol. It is preferably at least one selected from the group consisting of, and more preferably at least one selected from the group consisting of a polyhydric alcohol ester solvent and a terpene solvent.

  As the resin, any resin that is usually used in the technical field can be used without particular limitation as long as it is a resin that can be thermally decomposed by heat treatment (firing), and even a natural polymer compound may be a synthetic polymer compound. May be. Specifically, examples of the resin include cellulose resins such as methyl cellulose, ethyl cellulose, carboxymethyl cellulose, and nitrocellulose; polyvinyl alcohol compounds, polyvinyl pyrrolidone compounds, acrylic resins such as polyethyl acrylate, vinyl acetate-acrylate copolymers, polyvinyl Examples include butyral resins such as butyral, phenol-modified alkyd resins, alkyd resins such as castor oil fatty acid-modified alkyd resins, epoxy resins, phenol resins, and rosin ester resins. One type of resin may be used alone, or two or more types may be used in combination.

  The resin is preferably at least one selected from the group consisting of a cellulose resin and an acrylic resin from the viewpoint of disappearance in heat treatment (firing).

  The weight average molecular weight of the resin is not particularly limited. The weight average molecular weight of the resin is, for example, preferably 5,000 to 500,000, and more preferably 10,000 to 300,000. It exists in the tendency which can suppress the increase in the viscosity of the composition for base electrodes as the weight average molecular weight of resin is 5000 or more. This can be considered, for example, because the three-dimensional repulsion when the resin is adsorbed on the metal particles is sufficient, and aggregation of these resins is suppressed. On the other hand, when the weight average molecular weight of the resin is 500,000 or less, aggregation of the resins in the solvent is suppressed, and an increase in the viscosity of the composition for the base electrode tends to be suppressed. Further, if the weight average molecular weight of the resin is 500,000 or less, the resin combustion temperature is suppressed from being increased, and the resin remains as a foreign substance without being burned when the base electrode composition is heat-treated (fired). Is suppressed, and a lower resistivity base electrode tends to be formed.

A weight average molecular weight is calculated | required by converting using the analytical curve of a standard polystyrene from the molecular weight distribution measured using GPC (gel permeation chromatography). The calibration curve is approximated in three dimensions using five standard polystyrene sample sets (PStQuick MP-H, PStQuick B, Tosoh Corporation). The measurement conditions for GPC are as follows.
Apparatus: (Pump: L-2130 type [Hitachi High-Technologies Corporation]), (Detector: L-2490 type RI [Hitachi High-Technologies Corporation]), (Column oven: L-2350 [Corporation] Hitachi High-Technologies])
Column: Gelpack GL-R440 + Gelpack GL-R450 + Gelpack GL-R400M (3 in total) (Hitachi Chemical Co., Ltd.)
-Column size: 10.7 mm x 300 mm (inner diameter)
・ Eluent: Tetrahydrofuran ・ Sample concentration: 10 mg / 2 mL
・ Injection volume: 200 μL
・ Flow rate: 2.05 mL / min ・ Measurement temperature: 25 ° C.

  When the base electrode composition contains at least one selected from the group consisting of a solvent and a resin, the content of the solvent and the resin is the solvent used so that the base electrode composition has desired liquid properties. And it can select suitably according to the kind of resin. For example, the total content of the solvent and the resin is preferably 3.0% by mass to 50.0% by mass, and preferably 5.0% by mass to 45.0% by mass in the composition for base electrode. More preferably, it is 7.0 mass%-40.0 mass%. When the total content of the solvent and the resin is within the above range, the application characteristics when applying the base electrode composition to the capacitor body are improved, and the base electrode having a desired width and height is more easily obtained. There is a tendency to form.

  When the base electrode composition contains at least one selected from the group consisting of a solvent and a resin, the content ratio of the solvent and the resin is a solvent used so that the base electrode composition has desired liquid properties. And it can select suitably according to the kind of resin.

  From the viewpoint of oxidation resistance, lower resistivity of the base electrode, and adhesion to the capacitor body, the base electrode composition has a total content of metal particles of, for example, 30.0 mass% to 94.0 mass%. It is preferable that the glass particle content is 0.1% by mass to 15.0% by mass, the total content of the metal particles is 35.0% by mass to 90.0% by mass, The content is more preferably 0.5% by mass to 12.0% by mass, the total content of the metal particles is 40.0% by mass to 85.0% by mass, and the content of the glass particles is 1. More preferably, it is 0 mass%-10.0 mass%.

  In the case where the composition for the base electrode contains at least one selected from the group consisting of a solvent and a resin, from the viewpoint of oxidation resistance, low resistivity of the base electrode, and adhesion to the capacitor body, for example, metal The total content of the particles is 30.0 mass% to 94.0 mass%, the content of the glass particles is 0.1 mass% to 15.0 mass%, and the total content of the solvent and the resin is 3. It is preferable that it is 0 mass%-50.0 mass%, the total content rate of a metal particle is 35.0 mass%-90.0 mass%, and the content rate of a glass particle is 0.5 mass%-12. More preferably, the total content of the solvent and the resin is 5.0% by mass to 45.0% by mass, and the total content of the metal particles is 40.0% by mass to 85.0% by mass. The glass particle content is 1.0 mass% to 10.0 mass%, and the solvent and It is more preferable that the total content of fat is 7.0 wt% 40.0 wt%.

(flux)
The base electrode composition may contain at least one flux. By containing the flux, when an oxide film is formed on the surface of the metal particles, the oxide film is removed, and the reaction of the metal particles during the heat treatment (firing) tends to be promoted. Moreover, it exists in the tendency which the adhesiveness of a base electrode and a capacitor | condenser main body improves more by containing a flux.

  The flux is not particularly limited as long as the oxide film formed on the surface of the metal particles can be removed. Specifically, for example, fatty acids, boric acid compounds, fluorinated compounds, and borofluorinated compounds can be mentioned as preferred fluxes. A flux may be used individually by 1 type and may be used in combination of 2 or more type.

  More specifically, as the flux, for example, lauric acid, myristic acid, palmitic acid, stearic acid, sorbic acid, stearic acid, propionic acid, boron oxide, potassium borate, sodium borate, lithium borate, potassium borofluoride , Sodium borofluoride, lithium borofluoride, acidic potassium fluoride, acidic sodium fluoride, acidic lithium fluoride, potassium fluoride, sodium fluoride, and lithium fluoride.

  Of these, potassium borate and potassium borofluoride are preferable fluxes from the viewpoint of heat resistance during heat treatment (firing) (the property that the flux does not volatilize at low temperatures during heat treatment (firing)) and the oxidation resistance of metal particles. It is done.

  When the composition for the base electrode contains a flux, the content of the flux is the ratio of the porosity formed by removing the flux by heat treatment (firing) from the viewpoint of effectively expressing the oxidation resistance of the metal particles. From the viewpoint of reduction, in the composition for the base electrode, for example, it is preferably 0.1% by mass to 5% by mass, more preferably 0.3% by mass to 4% by mass, and 0.5% by mass. It is more preferable that it is -3.5 mass%, it is especially preferable that it is 0.7 mass%-3 mass%, and it is very preferable that it is 1 mass%-2.5 mass%.

(Other ingredients)
In addition to the above-described components, the base electrode composition may further contain other components that are usually used in the technical field, if necessary. Examples of other components include plasticizers, dispersants, surfactants, inorganic binders, metal oxides, ceramics, and organometallic compounds.

(Preparation method of composition for base electrode)
The method for preparing the composition for the base electrode is not particularly limited. It can be prepared by dispersing and mixing metal particles, glass particles, and other components such as a solvent and a resin that are used as necessary, using a commonly used dispersion method and mixing method.
The dispersion method and the mixing method are not particularly limited, and can be appropriately selected and applied from commonly used dispersion methods and mixing methods.

<Formation method of base electrode>
The method for forming the base electrode using the base electrode composition includes a step of applying the base electrode composition to the capacitor body (hereinafter also referred to as “applying step”), and heat-treating the applied base electrode composition ( And a step of forming a base electrode (hereinafter also referred to as “base electrode forming step”). Between the application | coating process and a base electrode formation process, you may have the process (henceforth a "drying process") which dries the provided composition for base electrodes as needed. Moreover, between the application | coating process and a base electrode formation process, it has the process (henceforth a "degreasing process") which thermally decomposes the resin in the provided composition for base electrodes as needed. May be.
By using the base electrode composition described above, a base electrode having a low resistivity can be formed even when heat treatment (baking) is performed in the presence of oxygen (for example, in the air).

(Granting process)
In the applying step, the base electrode composition is applied to the region of the capacitor body where the base electrode is to be formed so as to have a desired shape. Examples of the method for applying the composition for the base electrode include a screen printing method, an ink jet method, a dispenser method, and a dip method. Among these, the screen printing method or the dipping method is preferable from the viewpoint of productivity.

  When applying the base electrode composition to the capacitor body, the base electrode composition is preferably in the form of a paste. The paste-like composition for base electrode preferably has a viscosity in the range of 20 Pa · s to 1000 Pa · s. In addition, the viscosity of the composition for base electrodes is measured using a Brookfield HBT viscometer at a temperature of 25 ° C. and a rotational speed of 5.0 revolutions / minute (rpm).

The amount of the base electrode composition applied to the capacitor body can be appropriately selected according to the size of the base electrode to be formed. For example, the application amount of the base electrode composition ^may be a ^{3g / m 2 ~120g / m 2} , it is preferably ^{5g / m 2 ~100g / m 2} .

(Drying process)
When forming a base electrode using the composition for base electrodes, you may provide a drying process for the purpose of evaporating the solvent in the composition for base electrodes as needed. A drying process is performed after an application | coating process, for example, heat-treats the composition for base electrodes at the temperature of less than 300 degreeC for 1 second-30 minutes. By the drying step, the solvent contained in the composition for the base electrode is evaporated, and the formation of voids due to residues in the base electrode tends to be suppressed.

  The conditions for the drying step can be appropriately set according to the type of dielectric of the capacitor body, the type of solvent in the base electrode composition, the application amount of the base electrode composition, and the like. In the drying step, from the viewpoint of productivity, for example, it is preferable to perform a heat treatment for 2 seconds to 20 minutes at a temperature of 280 ° C. or less, and it is more preferable to perform a heat treatment for 3 seconds to 15 minutes at a temperature of 250 ° C. or less. .

  The apparatus used for the drying step is not particularly limited as long as it can be heated to the above temperature, and examples thereof include an air dryer, a hot plate, a tunnel furnace, and a belt furnace.

(Base electrode formation process)
In the base electrode forming step, the applied base electrode composition is heat-treated (fired) to form the base electrode. As a heat treatment (firing) condition in the base electrode forming step, a heat treatment (firing) condition usually used in the technical field can be applied. Generally, the heat treatment (firing) temperature is set to 900 ° C. or lower, and can be set in the range of 600 ° C. to 900 ° C., for example. Further, the heat treatment (firing) time can be appropriately selected according to the heat treatment (firing) temperature and the like, and can be, for example, 10 seconds to 2 hours in a temperature range of 600 ° C to 900 ° C.

(Degreasing process)
When forming the base electrode using the base electrode composition, if necessary, degreasing is performed for the purpose of thermally decomposing the resin in the base electrode composition between the application step and the base electrode formation step. A process can be provided. By the degreasing process, the resin contained in the composition for the base electrode is thermally decomposed, and the resin component tends to be suppressed from remaining as a residue in the base electrode. For this reason, the reaction and sintering of the metal particles are inhibited from being inhibited by the resin component residue, and a low-resistance ground electrode tends to be formed. In addition, the Sn—PO glass phase can be effectively generated during the heat treatment (firing), and the adhesion between the base electrode and the capacitor body tends to be improved.

  In the degreasing step, for example, heat treatment is performed at a temperature of 300 ° C. or higher and lower than 600 ° C. for 5 seconds to 3 hours. The conditions of the degreasing step can be appropriately set according to the type of dielectric of the capacitor body, the type of resin in the base electrode composition, the application amount of the base electrode composition, and the like. In the degreasing step, it is preferable to perform heat treatment at a temperature of 350 ° C. to 550 ° C. for 5 seconds to 3 hours from the viewpoint of productivity and lower resistivity of the base electrode, and at a temperature of 350 ° C. to 500 ° C. for 10 seconds to It is more preferable to perform the heat treatment for 2 hours.

  The apparatus used for the degreasing step and the base electrode forming step is not particularly limited as long as it can be heated to the above temperature, and examples thereof include an infrared heating furnace, a tunnel furnace, and a belt furnace. The infrared heating furnace is highly efficient because electric energy is input to the heat treatment material in the form of electromagnetic waves and converted into heat energy, and rapid heating is possible in a short time. Furthermore, since there are few products by combustion and non-contact heating, it is possible to suppress contamination of the base electrode to be formed. Tunnel furnaces and belt furnaces automatically and continuously convey samples from the inlet to the outlet for heat treatment (firing), so the unevenness of heat treatment (firing) is suppressed by controlling the furnace body classification and the transfer speed. Is possible. Under such circumstances, from the viewpoint of productivity, it is preferable to perform heat treatment (firing) using a tunnel furnace or a belt furnace.

  In addition, it is preferable to use a tunnel furnace or a belt furnace also from a viewpoint which can perform a degreasing process and a base electrode formation process continuously. For example, after applying a composition for a base electrode and placing a dried capacitor body in a tunnel furnace or belt furnace and heat-treating under the conditions of a degreasing process, the capacitor body is not taken out from the tunnel furnace or belt furnace. By changing the setting of the temperature, etc., a base electrode that is a heat-treated (fired) product of the base electrode composition may be formed by heat treatment (firing) under the conditions of the base electrode forming step.

<Manufacturing method of chip capacitor>
The manufacturing method of the chip capacitor of the present embodiment includes a step of applying the base electrode composition to the capacitor body (application step), and a step of heat-treating (firing) the applied base electrode composition to form a base electrode ( A base electrode forming step). Between the application | coating process and a base electrode formation process, you may have the process (drying process) of drying the provided composition for base electrodes as needed. Moreover, you may have the process (degreasing process) of thermally decomposing | disassembling resin in the provided composition for base electrodes between the provision process and the base electrode formation process as needed. That is, the chip capacitor manufacturing method of this embodiment includes a step of forming a base electrode by the above-described forming method.
By using the base electrode composition described above, a base electrode having a low resistivity can be formed even when heat treatment (baking) is performed in the presence of oxygen (for example, in the air).

A more detailed manufacturing method is as follows, for example.
First, the raw material particles of the dielectric layer are weighed and mixed, calcined, and pulverized to obtain fine dielectric particles. Next, a dielectric paste is prepared by adding a solvent, a resin or the like to the dielectric particles, which is applied on a carrier film or the like so as to have a predetermined thickness, and dried to obtain a ceramic green sheet. Thereafter, the internal electrode composition is applied onto the ceramic green sheet by a method such as printing, and dried. Next, a plurality of ceramic green sheets to which the composition for internal electrodes has been applied and dried are laminated and pressed to form a ceramic green sheet laminate. Thereafter, the ceramic green sheet laminate is cut into a predetermined size to form chips, and heat treatment (firing) is performed to obtain a capacitor body in which a plurality of dielectric layers and internal electrode layers are alternately laminated.
Next, the base electrode composition is applied to both ends of the capacitor body in the direction in which the internal electrode layer extends, and the base electrode is formed by heat treatment (firing).
Finally, an electrode film made of copper (Cu), nickel (Ni), tin (Sn), gold (Au), silver (Ag), or the like is formed by electrolytic plating or the like, and an external electrode is formed in the region covering the base electrode. Form.

(Dielectric layer)
In general, raw material particles containing barium titanate (BaTiO ₃ ) as a main raw material are used for forming the dielectric layer. BaTiO ₃ particles can be produced by a commonly used method. For example, the bulk material may be pulverized by a ball mill or the like, or may be manufactured by a method such as a sol-gel method or a hydrothermal method.

The raw material particles for the dielectric layer preferably include particles of a compound other than BaTiO ₃ . This can be considered as follows, for example.
Nickel (Ni) or copper (Cu) is mainly used for the internal electrode layers stacked alternately with the dielectric layers, but these metals have high resistance due to oxidation when heat-treated (fired) in the atmosphere. There is a tendency to become. For this reason, the heat treatment (firing) of the ceramic green sheet laminate is performed, for example, in a reducing atmosphere such as a mixed gas of hydrogen gas and nitrogen gas. On the other hand, it is known that BaTiO ₃ becomes a semiconductor in a reducing atmosphere and causes a decrease in dielectric constant. For this reason, raw material particles include strontium (Sr), calcium (Ca), magnesium (Mg), manganese (Mn), dysprosium (Dy), holmium (Ho), yttrium (Y), niobium (Nb), tantalum ( It is preferable to add a compound containing an element such as Ta) or tungsten (W). By adding such a compound, there is a tendency that a dielectric layer having both high insulating properties and high dielectric constant can be easily obtained even if heat treatment (firing) is performed in a reducing atmosphere.

Examples of particles of compounds other than BaTiO ₃ added to the raw material particles include, for example, strontium oxide (SrO), calcium oxide (CaO), magnesium oxide (MgO), manganese oxide (MnO), manganese carbonate (MnCO ₃ ), From dysprosium oxide (Dy ₂ O ₃ ), holmium oxide (Ho ₂ O ₃ ), yttrium oxide (Y ₂ O ₃ ), niobium oxide (NbO), tantalum oxide (Ta ₂ O ₅ ), and tungsten oxide (WO ₃ ) And at least one particle selected from the group consisting of:

Among them, at least selected from the group consisting of strontium oxide (SrO), calcium oxide (CaO), magnesium oxide (MgO), manganese oxide (MnO), manganese carbonate (MnCO ₃ ), and yttrium oxide (Y ₂ O ₃ ). Preferably it contains one type of particle. By adding such compound particles to the raw material particles, it is easy to obtain a dielectric layer having both high insulating properties and high dielectric constant even when heat-treated (fired) in a reducing atmosphere. As a result, the reliability tends to improve.

When the raw material particles include particles of other compounds other than BaTiO ₃ , the content of the particles of other compounds in the raw material particles is preferably 0.1% by mass to 5.0% by mass, for example. It is more preferable that it is 0.2 mass%-4.5 mass%, and it is still more preferable that it is 0.3 mass%-4.0 mass%. By setting the content of other compound particles to 0.1 mass% or more, the insulation and reliability of the dielectric tend to be improved. On the other hand, the dielectric constant of the dielectric layer tends to be kept high by setting the content of the other compound particles to 5.0 mass% or less.

  The heat treatment conditions when the raw material particles are weighed, mixed and calcined are, for example, 1 hour to 3 hours at a temperature of 600 ° C. to 1000 ° C. in the atmosphere or in a mixed gas atmosphere of hydrogen gas and nitrogen gas. be able to. Existing equipment can be used for pulverization after calcination, and for example, a ball mill or the like can be used.

The particle diameter of the dielectric particles mainly composed of BaTiO ₃ obtained as described above can be appropriately selected according to the thickness of the dielectric layer to be formed. The D50% of the dielectric particles is, for example, preferably 50 nm to 1.5 μm, and more preferably 75 nm to 1.0 μm. By setting D50% of the dielectric particles to 50 nm or more, there is a tendency that a decrease in ferroelectricity due to the particle size effect of BaTiO ₃ can be suppressed. On the other hand, by setting D50% of the dielectric particles to 1.5 μm or less, the sinterability of the dielectric particles during heat treatment (firing) tends to be improved.

  In addition, the measuring method of the particle diameter (D50%) of dielectric particles is the same as the measuring method of the particle diameter of phosphorus-containing copper alloy particles and glass particles.

  The shape of the dielectric particles is not particularly limited, and may be any of a substantially spherical shape, a flat shape, a block shape, a plate shape, a scale shape, and the like. From the viewpoint of sinterability and denseness of the dielectric layer, the shape of the dielectric particles is preferably substantially spherical, flat, or plate-like.

When preparing a dielectric paste using the dielectric particles obtained above, the solvent, resin, etc. to be added are not particularly limited. For example, it can be used by selecting from the solvent and resin that can be contained in the above-mentioned composition for the base electrode.
The method for preparing the dielectric paste is not particularly limited. For example, it can be prepared by dispersing and mixing other components such as dielectric particles, a solvent, a resin, and optionally added glass particles using a commonly used dispersion method and mixing method. . The dispersion method and the mixing method are not particularly limited, and can be appropriately selected and applied from commonly used dispersion methods and mixing methods.

  The method for producing the ceramic green sheet using the dielectric paste is not particularly limited. For example, a method of applying a dielectric paste on a peelable film or the like and drying as necessary can be mentioned. As a method for applying the dielectric paste, it is preferable to use a doctor blade method from the viewpoint of productivity and uniformity of the thickness of the ceramic green sheet.

The amount of the dielectric paste applied to the film or the like can be appropriately selected according to the thickness of the ceramic green sheet to be formed. For example, the application amount of the dielectric ^paste, it is possible to ^{0.01g / m 2 ~20g / m 2} , is preferably ^{0.05g / m 2 ~15g / m 2} .

  The drying conditions in the case of drying after applying the dielectric paste can be appropriately set according to, for example, the type of film, the type of solvent, and the applied amount of the dielectric paste. From the viewpoint of productivity, for example, the drying condition is preferably 2 seconds to 20 minutes at a temperature of 280 ° C. or less, and more preferably 3 seconds to 15 minutes at a temperature of 250 ° C. or less.

  The apparatus used for drying the dielectric paste is not particularly limited as long as it can be heated to the above temperature, and examples thereof include a blower dryer, a hot plate, a tunnel furnace, and a belt furnace.

(Internal electrode layer)
Examples of the method for forming the internal electrode layer include a method in which the composition for internal electrodes is applied to the ceramic green sheet obtained above by a method such as printing and dried.

  In general, a paste containing metal particles made of nickel (Ni) or copper (Cu) is used for the internal electrode composition. The metal particles can be produced by a commonly used method. For example, it may be manufactured by pulverizing from a bulk body with a ball mill or the like, or may be manufactured using a water atomizing method.

  The content of the metal particles in the composition for internal electrodes is, for example, preferably 30.0% by mass to 94.0% by mass, and more preferably 35.0% by mass to 90.0% by mass. More preferably, it is 40.0 mass%-85.0 mass%. By setting the content of the metal particles in the internal electrode composition to 30.0% by mass or more, voids in the internal electrode layer can be effectively reduced and the internal electrode layer tends to be densified. . On the other hand, when the content of the metal particles in the internal electrode composition is 94.0% by mass or less, the workability when applied to the ceramic green sheet tends to be improved.

  The particle diameter of the metal particles can be appropriately selected according to the thickness of the internal electrode layer to be formed. The D50% of the metal particles is preferably, for example, 50 nm to 1.0 μm, and more preferably 75 nm to 0.8 μm. By setting D50% of the metal particles to 50 nm or more, it becomes easy to adjust the liquid physical properties of the composition for internal electrodes, and the workability when applied to the ceramic green sheet tends to be improved. On the other hand, when the D50% of the metal particles is 1.0 μm or less, the sinterability of the metal particles during heat treatment (firing) tends to be improved.

  In addition, the measuring method of the particle diameter (D50%) of a metal particle is the same as the measuring method of the particle diameter of phosphorus containing copper alloy particle | grains and a glass particle.

  The shape of the metal particles is not particularly limited, and may be any of a substantially spherical shape, a flat shape, a block shape, a plate shape, a scale shape, and the like. From the viewpoint of sinterability and denseness of the internal electrode layer, the shape of the metal particles is preferably substantially spherical, flat or plate-like.

  The internal electrode composition is preferably in the form of a paste, and more preferably contains at least one selected from the group consisting of a solvent and a resin. By containing at least one selected from the group consisting of a solvent and a resin, the range suitable for the application method when applying the liquid physical properties (viscosity, surface tension, etc.) of the composition for internal electrodes to the ceramic green sheet Can be adjusted in.

The solvent, resin, and the like to be added are not particularly limited, and can be selected and used, for example, from the solvent and resin that can be contained in the above-described base electrode composition.
Moreover, the preparation method of the composition for internal electrodes is not particularly limited. For example, it can be prepared by dispersing and mixing other components such as metal particles, a solvent, a resin, and dielectric particles that are added as necessary using a commonly used dispersion method and mixing method. . The dispersion method and the mixing method are not particularly limited, and can be appropriately selected and applied from commonly used dispersion methods and mixing methods.

  As a method of applying the internal electrode composition to the ceramic green sheet, it is preferable to use a screen printing method from the viewpoint of productivity and uniformity of the thickness of the internal electrode layer.

The amount of the internal electrode composition applied to the ceramic green sheet can be appropriately selected according to the thickness of the internal electrode layer to be formed. For example, the application amount of the internal electrode composition ^can be a ^{0.01g / m 2 ~20g / m 2} , is preferably ^{0.05g / m 2 ~15g / m 2} .

  The drying conditions after applying the composition for internal electrodes can be appropriately set according to the type (composition) and surface shape of the ceramic green sheet, the type of solvent, and the application amount of the composition for internal electrodes. From the viewpoint of productivity, for example, the drying condition is preferably 2 seconds to 20 minutes at a temperature of 280 ° C. or less, and more preferably 3 seconds to 15 minutes at a temperature of 250 ° C. or less.

  The apparatus used for drying the composition for internal electrodes is not particularly limited as long as it can be heated to the above temperature, and examples thereof include a blower dryer, a hot plate, a tunnel furnace, and a belt furnace.

(Capacitor body)
The capacitor body is obtained by, for example, laminating a plurality of ceramic green sheets to which the composition for internal electrodes has been applied and dried, and forming the ceramic green sheet laminate by pressing to form a ceramic green sheet laminate having a predetermined size. It is obtained by cutting into chips and chipping and heat treatment (firing).

  The number of laminated ceramic green sheets to which the composition for internal electrodes has been applied and dried is appropriately selected according to the size and characteristics of the chip capacitor as a product. For example, the number of stacked layers can be 10 to 1000.

  The pressurizing condition after laminating the ceramic green sheets can be appropriately selected depending on the type (composition) of the ceramic green sheets, the number of laminated layers, and the like. The pressurizing condition of the ceramic green sheet is preferably, for example, a temperature of 20 ° C. to 200 ° C. and a pressure of 10 MPa to 500 MPa for 10 seconds to 60 minutes, a temperature of 30 ° C. to 150 ° C. and a pressure of 15 MPa to 350 MPa. More preferably, it is 20 seconds to 45 minutes.

The ceramic green sheet laminate obtained above is chipped into a predetermined size and then heat-treated (fired) in an atmosphere where the oxygen partial pressure is atmospheric from the viewpoint of suppressing oxidation of the metal particles for the internal electrode. A lower atmosphere is preferable. For example, a nitrogen atmosphere with an oxygen partial pressure of 1 × 10 ⁻⁵ Pa or less is preferable. Moreover, the heat processing (baking) conditions of the cut | disconnected ceramic green sheet laminated body can be 30 minutes-6 hours at the temperature of 850 degreeC-1200 degreeC, for example.

(Base electrode and external electrode)
The base electrode is formed by applying the above-described composition for the base electrode to both ends of the capacitor body obtained in the above in the direction in which the internal electrode layer extends, and performing heat treatment (firing).
Here, even when the heat treatment (firing) for forming the base electrode is performed in an air atmosphere, the metal (for example, copper or nickel) in the internal electrode layer can be prevented from being oxidized. . This is because the internal electrode layer is exposed to the atmosphere during heat treatment (firing) by applying the base electrode composition so as to cover both end faces of the capacitor body in the direction in which the internal electrode layer extends. It is thought that it is possible to prevent.

  As a method for forming the external electrode, an electroplating method is mainly cited. Specifically, materials such as Cu / Ni / Sn, Ni / Sn, Ni / Au, and Ni / Ag can be plated in this order. By using the base electrode composition described above, it is possible to maintain good adhesion between the base electrode and the external electrode, regardless of the type of plating.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. Unless otherwise specified, “part” is based on mass.

<Example 1>
(A) Preparation of composition 1 for base electrode A phosphorus-containing copper alloy containing 93.0% by mass of copper and 7.0% by mass of phosphorus was prepared by a conventional method, and this was melted and water atomized. After granulating, it was dried and classified. For classification, a forced vortex classifier (Turbo Classifier TC-15, Nissin Engineering Co., Ltd.) was used. The classified particles were mixed with an inert gas and subjected to deoxidation and dehydration treatment to produce phosphorus-containing copper alloy particles containing 93.0% by mass of copper and 7.0% by mass of phosphorus. The phosphorus-containing copper alloy particles had a particle diameter (D50%) of 5.0 μm and a substantially spherical shape.

1. silicon dioxide (SiO ₂ ) 3.5% by mass, boron oxide (B ₂ O ₃ ) 14.3% by mass, bismuth oxide (Bi ₂ O ₃ ) 79.3% by mass, aluminum oxide (Al ₂ O ₃ ) A glass having a composition of 4% by mass and 0.5% by mass of lithium oxide (Li ₂ O) (hereinafter sometimes abbreviated as “G01”) was prepared, and this was pulverized to obtain a particle size (D50% ) Was obtained as glass G01 particles having a thickness of 1.1 μm. The softening point of the glass G01 particles was 415 ° C., and the shape thereof was substantially spherical.

  In addition, the shape of phosphorus containing copper alloy particle | grains and glass particle | grains was observed and determined using the scanning electron microscope (TM-1000 type | mold, Hitachi High-Technologies Corporation). The particle diameters (D50%) of phosphorus-containing copper alloy particles and glass particles were calculated using a laser scattering diffraction particle size distribution analyzer (LS 13 320 type, Beckman Coulter, Inc., measurement wavelength: 632 nm). The softening point of the glass particles was obtained from a differential heat (DTA) curve using a simultaneous differential heat / thermogravimetric measuring device (DTG-60H type, Shimadzu Corporation). Specifically, in the DTA curve, the softening point can be estimated from the endothermic part.

  67.0 parts of the phosphorus-containing copper alloy particles obtained above, 8.0 parts of glass G01 particles, 20.0 parts of diethylene glycol monobutyl ether (BC), and ethyl polyacrylate (EPA, Fujikura Kasei Co., Ltd.) , Weight average molecular weight: 155000) was mixed and mixed using an automatic mortar kneader to form a paste, thereby preparing a composition 1 for a base electrode.

(B) Preparation of the chip capacitor First, as a raw material particles in the dielectric layer, 97.5 parts of barium titanate (BaTiO ₃₎ particles, yttrium oxide _(Y 2 _{O 3)} 1.5 parts of the particles, magnesium oxide (MgO ) 0.8 parts of particles and 0.2 parts of manganese oxide (MnO) particles were prepared. These were mixed in a ball mill, pulverized, calcined at 700 ° C. for 1 hour in the atmosphere, and further pulverized in a ball mill to obtain dielectric particles having an average particle size of 0.1 μm.

  Next, 75.0 parts of the dielectric particles obtained above, 0.5 part of ethyl cellulose, 10.5 parts of toluene, and 14.0 parts of diethylene glycol monobutyl ether (BC) are mixed together to form a zirconia ball having a diameter of 5 mm. And a zirconia pot were mixed to prepare a dielectric paste.

  Next, the dielectric paste obtained above was applied onto a carrier film. Specifically, the application conditions were appropriately adjusted by a doctor blade method so that the thickness after drying was 2.0 μm. Thereafter, the carrier film was dried for 3 minutes at a temperature of 65 ° C. using a hot air dryer, and the obtained ceramic green sheet was peeled off from the carrier film and taken out.

  Next, 85.0 parts of Ni particles (average particle size: 0.5 μm), 0.5 parts of ethyl cellulose, and 14.5 parts of diethylene glycol monobutyl ether (BC) are mixed and mixed using an automatic mortar kneader. A composition for internal electrodes was prepared by pasting.

Next, the internal electrode composition was applied to the entire upper surface of the ceramic green sheet obtained above. Specifically, the application conditions were appropriately adjusted by a screen printing method so that the thickness after lamination, pressurization, and heat treatment (firing) was 1.0 μm.
The ceramic green sheet provided with the composition for internal electrodes was dried by placing it in an oven heated to 150 ° C. for 1 minute.

  Next, 200 ceramic green sheets provided with the composition for internal electrodes were laminated, 15 ceramic green sheets not provided with the composition for internal electrodes were laminated on the upper and lower surfaces, respectively, and the temperature was 65 using a press. A ceramic green sheet laminate was obtained by pressurizing at 150 ° C. and a pressure of 150 MPa for 10 minutes. The thickness of the ceramic green sheet laminate was 0.50 mm.

The ceramic green sheet laminate is cut into a size of 1.00 mm x 0.50 mm x 0.50 mm, and the highest in an atmospheric atmosphere using a tunnel furnace (single-line transport W / B tunnel furnace, Noritake Co., Ltd.) A heat treatment was performed at a temperature of 350 ° C. for a holding time of 10 minutes to burn and decompose (degrease) the resin component in the ceramic green sheet laminate.
Furthermore, using a cantal furnace, heat treatment (firing) is performed at a temperature of 1100 ° C. for 2 hours in a mixed gas atmosphere of hydrogen gas and nitrogen gas (oxygen partial pressure is 10 ⁻⁸ Pa) to obtain a capacitor body. It was.

  The base electrode composition 1 prepared above was applied by the dipping method so as to be continuous from both end faces in the direction in which the internal electrode layers of the obtained capacitor main body extend to the end parts of the four adjacent faces. . The application conditions were appropriately adjusted so that the thickness after heat treatment (firing) was 20 μm. This was placed in an oven heated to 150 ° C. for 15 minutes, and the solvent was removed by evaporation.

  Subsequently, using a tunnel furnace (single-line transport W / B tunnel furnace, Noritake Co., Ltd.), a heat treatment (firing) is performed in an air atmosphere at a maximum temperature of 650 ° C. for a holding time of 10 seconds. Formed.

  Thereafter, nickel (Ni) and tin (Sn) were plated in this order on the region covering the base electrode by electrolytic barrel plating to form an external electrode, and the chip capacitor 1 was manufactured.

<Example 2>
In Example 1, except that the copper content of the phosphorus-containing copper alloy particles was changed from 93.0% by mass to 94.0% by mass, and the phosphorus content was changed from 7.0% by mass to 6.0% by mass. In the same manner as in Example 1, a base electrode composition 2 was prepared. Then, a base electrode was formed in the same manner as in Example 1 except that the base electrode composition 2 was used instead of the base electrode composition 1, and a chip capacitor 2 was produced.

<Example 3>
In Example 1, except that the heat treatment (firing) conditions for forming the base electrode were changed from the maximum temperature of 650 ° C. for the holding time of 10 seconds to the maximum temperature of 700 ° C. for the holding time of 10 seconds. Similarly, a base electrode was formed, and a chip capacitor 3 was produced.

<Example 4>
A phosphorus-tin-containing copper alloy containing 84.0% by mass of copper, 6.0% by mass of phosphorus, and 10.0% by mass of tin is prepared by a conventional method, and melted by a water atomizing method. After the formation of particles, drying, classification, deoxygenation, and dehydration treatment were performed in the same manner as in Example 1. 84.0% by mass of copper, 6.0% by mass of phosphorus, 10.0% by mass of tin, Phosphorus-tin-containing copper alloy particles containing were produced. The particle diameter (D50%) of the phosphorus-tin-containing copper alloy particles was 5.0 μm, and the shape thereof was substantially spherical.

  A base electrode composition 4 was prepared in the same manner as in Example 1 except that the phosphorus-containing copper alloy particles obtained above were used instead of the phosphorus-containing copper alloy particles. Then, a base electrode was formed in the same manner as in Example 3 except that the base electrode composition 4 was used instead of the base electrode composition 1, and a chip capacitor 4 was produced.

<Example 5>
A phosphorus-tin-nickel-containing copper alloy containing 57.5 mass% copper, 5.0 mass% phosphorus, 17.5 mass% tin, and 20.0 mass% nickel is prepared by a conventional method. Then, this was melted and granulated by the water atomization method, and then dried, classified, deoxygenated, and dehydrated in the same manner as in Example 1 to perform 57.5 mass% copper and 5.0 mass%. Phosphorus-tin-nickel-containing copper alloy particles containing phosphorus, 17.5 mass% tin, and 20.0 mass% nickel were produced. The particle diameter (D50%) of the phosphorus-tin-nickel-containing copper alloy particles was 5.0 μm, and the shape thereof was substantially spherical.

  In Example 1, the composition 5 for base electrodes was prepared like Example 1 except having used the phosphorus- tin- nickel containing copper alloy particle obtained above instead of the phosphorus containing copper alloy particle. did. Then, a base electrode was formed in the same manner as in Example 3 except that the base electrode composition 5 was used instead of the base electrode composition 1, and a chip capacitor 5 was produced.

<Example 6>
Example 5 is the same as Example 5 except that the heat treatment (firing) conditions for forming the base electrode were changed from the maximum temperature of 700 ° C. for the holding time of 10 seconds to the maximum temperature of 700 ° C. for the holding time of 20 seconds. Similarly, a base electrode was formed, and a chip capacitor 6 was produced.

<Example 7>
Example 5 is the same as Example 5 except that the heat treatment (firing) conditions for forming the base electrode were changed from the maximum temperature of 700 ° C. for the holding time of 10 seconds to the maximum temperature of 700 ° C. for the holding time of 30 seconds. Similarly, a base electrode was formed and a chip capacitor 7 was produced.

<Example 8>
Example 5 is the same as Example 5 except that the heat treatment (firing) conditions for forming the base electrode were changed from a maximum temperature of 700 ° C. for a holding time of 10 seconds to a maximum temperature of 750 ° C. for a holding time of 10 seconds. Similarly, a base electrode was formed to produce a chip capacitor 8.

<Example 9>
Example 5 is the same as Example 5 except that the heat treatment (firing) conditions for forming the base electrode were changed from a maximum temperature of 700 ° C. for a holding time of 10 seconds to a maximum temperature of 650 ° C. for a holding time of 60 seconds. Similarly, a base electrode was formed, and a chip capacitor 9 was produced.

<Example 10>
Silicon dioxide (SiO ₂ ) 1.2% by mass, lead oxide (PbO) 66.0% by mass, boron oxide (B ₂ O ₃ ) 12.5% by mass, bismuth oxide (Bi ₂ O ₃ ) 18.5% by mass And a glass having a composition of 1.8% by mass of aluminum oxide (Al ₂ O ₃ ) (hereinafter sometimes abbreviated as “G02”), and pulverized to obtain a particle size (D50%). Glass G02 particles having a size of 2.5 μm were obtained. The softening point of the glass G02 particles was 405 ° C., and the shape thereof was substantially spherical.

  In Example 5, glass G02 particles were used instead of glass G01 particles, and the content of each component was changed so as to have the composition shown in Table 1. Composition 10 was prepared. Then, a base electrode was formed in the same manner as in Example 5 except that the base electrode composition 10 was used instead of the base electrode composition 5, and a chip capacitor 10 was produced.

<Example 11>
In Example 5, the copper content of the phosphorus-tin-nickel-containing copper alloy particles was changed from 57.5% by mass to 75.0% by mass, and the phosphorus content was changed from 5.0% by mass to 6.0% by mass. In the same manner as in Example 5 except that the tin content was changed from 17.5% by mass to 9.0% by mass and the nickel content was changed from 20.0% by mass to 10.0% by mass. Thus, a composition 11 for a base electrode was prepared. Then, a base electrode was formed in the same manner as in Example 5 except that the base electrode composition 11 was used in place of the base electrode composition 5, and a chip capacitor 11 was produced.

<Example 12>
In Example 11, except that the particle diameter (D50%) of the phosphorus-tin-nickel-containing copper alloy particles was changed from 5.0 μm to 1.5 μm, the same as in Example 11, the composition for base electrode 12 Was prepared. Then, a base electrode was formed in the same manner as in Example 6 except that the base electrode composition 12 was used in place of the base electrode composition 5, and a chip capacitor 12 was manufactured.

<Example 13>
80.2 parts of phosphorus-containing copper alloy particles obtained in Example 1, 4.8 parts of glass G01 particles, 14.6 parts of terpineol (Ter), and ethyl cellulose (EC, Dow Chemical Company, weight average molecular weight) : 80000) was mixed together and mixed using an automatic mortar kneader to form a paste, thereby preparing a base electrode composition 13.

  In Example 1, the base electrode composition 13 was used in place of the base electrode composition 1, and the heat treatment (firing) conditions for forming the base electrode were changed from the maximum temperature of 650 ° C. and the holding time of 10 seconds to the maximum temperature. A base capacitor was formed in the same manner as in Example 1 except that the holding time was changed to 700 ° C. for 20 seconds, and a chip capacitor 13 was manufactured.

<Example 14>
In Example 5, the copper content of the phosphorus-tin-nickel-containing copper alloy particles was changed from 57.5% by mass to 60.0% by mass, and the phosphorus content was changed from 5.0% by mass to 6.0% by mass. In the same manner as in Example 5 except that the tin content was changed from 17.5% by mass to 15.0% by mass and the nickel content was changed from 20.0% by mass to 19.0% by mass. Thus, a composition 14 for a base electrode was prepared. Then, a base electrode was formed in the same manner as in Example 9 except that the base electrode composition 14 was used instead of the base electrode composition 5, and a chip capacitor 14 was produced.

<Example 15>
A base electrode composition 15 was prepared in the same manner as in Example 5 except that the content of each component was changed to have the composition shown in Table 1. Then, the base electrode composition 15 is used in place of the base electrode composition 5, and the heat treatment (firing) conditions for forming the base electrode are changed from a maximum temperature of 700 ° C. and a holding time of 10 seconds to a maximum temperature of 750 ° C. A base electrode was formed in the same manner as in Example 5 except that the holding time was changed to 60 seconds, and a chip capacitor 15 was manufactured.

<Comparative Example 1>
In Example 5, silver particles (particle diameter (D50%): 3.0 μm) were used instead of phosphorus-tin-nickel-containing copper alloy particles, and the content of each component was adjusted so as to have the composition shown in Table 1. Except having changed, it carried out similarly to Example 5, and prepared the composition C1 for base electrodes. Then, a base electrode was formed in the same manner as in Example 5 except that the base electrode composition C1 was used instead of the base electrode composition 5, and a chip capacitor C1 was produced.

<Comparative example 2>
In Example 5, copper particles (purity 99.5%, particle size (D50%): 5.0 μm) were used in place of the phosphorus-tin-nickel-containing copper alloy particles so that the composition shown in Table 1 was obtained. A base electrode composition C2 was prepared in the same manner as in Example 5 except that the content of each component was changed. Then, a base electrode was formed in the same manner as in Example 5 except that the base electrode composition C2 was used instead of the base electrode composition 5, and a chip capacitor C2 was produced.

<Comparative Example 3>
A tin-containing copper alloy containing 90.0% by mass of copper and 10.0% by mass of tin was prepared by a conventional method, melted and granulated by a water atomization method, and then the same as in Example 1. Drying, classification, deoxygenation, and dehydration were performed to produce tin-containing copper alloy particles containing 90.0% by mass of copper and 10.0% by mass of tin.

  A base electrode composition C3 was prepared in the same manner as in Example 5 except that the tin-containing copper alloy particles obtained above were used in place of the phosphorus-tin-nickel-containing copper alloy particles. did. Then, a base electrode was formed in the same manner as in Example 5 except that the base electrode composition C3 was used instead of the base electrode composition 5, and a chip capacitor C3 was produced.

<Comparative Example 4>
A tin-nickel-containing copper alloy containing 58.0% by mass of copper, 24.0% by mass of tin, and 18.0% by mass of nickel was prepared by a conventional method, and this was melted and subjected to a water atomization method. After particle formation, drying, classification, deoxygenation, and dehydration treatment were performed in the same manner as in Example 1, and 58.0% by mass of copper, 24.0% by mass of tin, and 18.0% by mass of nickel Tin-nickel-containing copper alloy particles containing were produced.

  In Example 5, ground electrode composition C4 was obtained in the same manner as in Example 5 except that the above-obtained tin-nickel-containing copper alloy particles were used instead of phosphorus-tin-nickel-containing copper alloy particles. Was prepared. Then, a base electrode was formed in the same manner as in Example 5 except that the base electrode composition C4 was used instead of the base electrode composition 5, and a chip capacitor C4 was produced.

<Comparative Example 5>
In Comparative Example 2, the base electrode was formed in the same manner as in Comparative Example 2, except that the heat treatment (firing) condition of the base electrode was changed from the air atmosphere to the nitrogen gas atmosphere (oxygen partial pressure was 1 Pa). A capacitor C5 was produced.

  Table 1 shows the compositions of the base electrode compositions and heat treatment (firing) conditions in Examples 1 to 15 and Comparative Examples 1 to 5. In Examples 1 to 15 and Comparative Examples 2 to 5, silver particles are not used, and therefore “-” is given to the column of silver particles in Table 1. In Comparative Example 1, since no copper alloy particles are used, the column of copper alloy particles in Table 1 is marked with “-”.

<Evaluation>
(Volume resistivity)
About the chip capacitor in a state where the base electrode was formed, the volume resistivity of the base electrode was measured by a four-probe method using a resistivity meter (Loresta-EP MCP-T360 type, Mitsubishi Chemical Corporation). The results are shown in Table 2.

(Cross-sectional structure of the base electrode)
For the chip capacitor in a state in which the base electrode was formed, the portion of the chip capacitor where the base electrode was formed was cut in the thickness direction of the electrode using a diamond cutter (RCO-961 type, Refinetech Co., Ltd.). . About the obtained cross section, it observed using the scanning electron microscope (TM-1000 type | mold, Hitachi High-Technologies Corporation). Further, the structure in the base electrode was analyzed using an energy dispersive X-ray spectrometer (EDX) attached to a scanning electron microscope (XL-30, FEI / Philips), and a Cu phase, a Cu—Sn alloy phase, The presence or absence of a Cu—Ni alloy phase, a Cu—Sn—Ni alloy phase, and a Sn—PO glass phase was confirmed. The results are shown in Table 2.

  In Comparative Example 1, since only silver particles were used as the metal particles in the base electrode composition C1, no structural analysis of the metal portion was performed.

(Adhesion test)
For the chip capacitor with the base electrode formed, the adhesion of the base electrode to the capacitor body was evaluated. Specifically, a stud pin (pin diameter: φ1.0 mm) is bonded onto the base electrode using an adhesive, and this is heated in the atmosphere using a 180 ° C. oven for 1 hour to obtain room temperature (25 C.). Thereafter, a tensile load was applied to the stud pin using a thin film adhesion strength measuring device (Romulus, QUAD GROUP), and the load at break was evaluated. At this time, the broken part was also observed. Two points were evaluated for each base electrode, and the average value was defined as the adhesion. The results are shown in Table 2.

(Evaluation of chip capacitors)
A terminal was attached to the external electrode of the manufactured chip capacitor. Thereafter, as a characteristic of the chip capacitor, an electrostatic capacity at a frequency of 1 kHz was measured by using an LCR meter (ZM2371, NF circuit design block). The evaluation was performed on five chip capacitors manufactured under the same conditions, and the average value was used as the initial capacitance.

Next, the chip capacitor whose initial capacitance was measured was held for 1000 hours in a high-temperature and high-humidity tank (light spec thermostatic chamber LHU-124, ESPEC Corp.) having a temperature of 85 ° C. and a humidity of 85%, and the chip capacitor was taken out. Then, after returning to room temperature (25 ° C.), 24 hours later, the capacitance was measured again. Moreover, the capacitance change after exposure to a high temperature and high humidity environment was calculated by the following formula (1). In the formula, C ₁ represents a capacitance after exposure to a high-temperature and high-humidity environment, and C ₀ represents an initial capacitance.
Capacitance change (%) = | (C ₁ −C ₀ ) | / C ₀ × 100 (1)

  In Comparative Examples 2 to 4, since the base electrode was oxidized during the heat treatment (firing) and the external electrode was not formed by electrolytic plating, the evaluation as a chip capacitor could not be performed.

  As can be seen from Table 2, in Comparative Examples 2 to 4, the resistance of the base electrode obtained by heat-treating (firing) the base electrode composition was increased. This is probably because the copper alloy particles contained in the composition for the base electrode do not contain phosphorus, and therefore the base electrode is oxidized without reduction of copper oxide to copper. The metal portion of the base electrode contained a large amount of copper oxide such as copper oxide (CuO), and no Cu phase was detected from the analysis. Of course, a glass phase containing phosphorus was not observed, and a melt of the glass frit used in the composition for the base electrode was confirmed.

  In Comparative Example 5, since the heat treatment (firing) of the composition for the base electrode was performed in a nitrogen atmosphere, the oxidation of copper as seen in Comparative Example 2 was suppressed, and from the analysis, the Cu phase was added to the base electrode. And was found to exhibit low volume resistivity.

On the other hand, some of the base electrodes formed in Examples 1 to 15 have a volume resistivity of about three times the maximum as compared with Comparative Examples 1 and 5, both of which are on the order of 1 × 10 ⁻⁵ Ω · cm. It showed a low value. It is considered that the Cu phase was confirmed from any of the base electrodes, and copper was effectively reduced by heat treatment (firing) in the atmosphere. Further, in the case where phosphorus-tin-containing copper alloy particles are used, in addition to the Cu phase, the Cu-Sn alloy phase is used. In the case where phosphorus-tin-nickel-containing copper alloy particles are used, in addition to the Cu phase, Cu- A Ni alloy phase and a Cu—Sn—Ni alloy phase were confirmed. In addition, in the base electrodes formed in Examples 1 to 15, the glass phase containing phosphorus was formed between the metal phase and the alloy phase shown in Table 2 and at the interface between the base electrode and the capacitor body.

  The adhesion strength of the base electrode formed in Examples 1 to 15 to the capacitor body was substantially the same as in Comparative Examples 1 and 5. From this, it can be seen that the adhesion of the base electrode to the capacitor body is improved by the wet and spread of the glass phase containing phosphorus produced by heat treatment (firing) on the surface of the capacitor body. In Comparative Examples 2 to 4, it is considered that the base electrode is occupied by a melt of metal oxide and glass frit and is in close contact with the capacitor body with a certain degree of strength.

  The initial capacitances of the chip capacitors produced in Examples 1 to 15 were almost the same as those of Comparative Examples 1 and 5. From this, even when the volume resistivity of the base electrode is increased from that of Comparative Example 1, the external electrode can be formed uniformly thereafter, and when Comparative Example 1 uses silver particles as the base electrode composition and Comparative Example 5, it was found that a high-performance chip capacitor could be manufactured in the same manner as when a nitrogen atmosphere was used for the heat treatment (firing) of the composition for the base electrode.

  Furthermore, the capacitance changes of the chip capacitors produced in Examples 1 to 15 were almost the same as those of Comparative Examples 1 and 5. From this, the volume resistivity of the base electrode and the rate of change in the contact resistance between the base electrode and the internal electrode layer when exposed to a high temperature and high humidity environment are obtained when silver particles are used in the composition for the base electrode in Comparative Example 1. And in Comparative Example 5, it was found that a high-performance chip capacitor could be manufactured in a similar manner to the case where a nitrogen atmosphere was used for the heat treatment (firing) of the base electrode composition.

DESCRIPTION OF SYMBOLS 1 ... Chip capacitor 2 ... Capacitor body 3 ... Dielectric layer 4 ... Internal electrode layer 5 ... Base electrode 6 ... External electrode 7 ... External electrode

Claims (17)

A capacitor body in which a plurality of dielectric layers and internal electrode layers are alternately laminated;
A base electrode electrically connected to the internal electrode layer of the capacitor body;
An external electrode provided on the base electrode,
The chip capacitor in which the base electrode includes a metal phase containing copper and a glass phase containing phosphorus and oxygen.   The chip capacitor according to claim 1, wherein the total content of metal and phosphorus in the base electrode is 40.0 mass% to 98.0 mass%.   3. The chip capacitor according to claim 1, wherein a phosphorus content in a total content of the metal and phosphorus in the base electrode is 2.0 mass% to 15.0 mass%.   The chip capacitor according to claim 1, wherein the metal phase of the base electrode further contains tin.   The chip capacitor according to claim 1, wherein the metal phase of the base electrode further contains nickel.   The base electrode contains at least one metal particle selected from the group consisting of phosphorus-containing copper alloy particles, phosphorus-tin-containing copper alloy particles, and phosphorus-tin-nickel-containing copper alloy particles, and glass particles. The chip capacitor according to any one of claims 1 to 5, wherein the chip capacitor is a heat-treated product of a composition for a base electrode.   The chip capacitor according to claim 6, wherein the phosphorus-containing copper alloy particles have a phosphorus content of 2.0 mass% to 15.0 mass%.   The chip capacitor according to claim 6 or 7, wherein the phosphorus-tin-containing copper alloy particles have a phosphorus content of 2.0 mass% to 15.0 mass%.   The chip capacitor according to any one of claims 6 to 8, wherein the phosphorus-tin-containing copper alloy particles have a tin content of 3.0 mass% to 30.0 mass%.   10. The chip capacitor according to claim 6, wherein the phosphorus-tin-nickel-containing copper alloy particles have a phosphorus content of 2.0 mass% to 15.0 mass%.   The chip capacitor according to any one of claims 6 to 10, wherein the phosphorus-tin-nickel-containing copper alloy particles have a tin content of 3.0 mass% to 30.0 mass%.   The chip capacitor according to claim 6, wherein the phosphorus-tin-nickel-containing copper alloy particles have a nickel content of 3.0% by mass to 30.0% by mass.   The chip capacitor according to any one of claims 6 to 12, wherein a total content of the metal particles in the base electrode composition is 30.0 mass% to 94.0 mass%.   The chip capacitor according to any one of claims 6 to 13, wherein a content ratio of the glass particles in the base electrode composition is 0.1 mass% to 15.0 mass%.   The chip capacitor according to claim 6, wherein the composition for base electrode further contains a resin.   The chip capacitor according to claim 6, wherein the composition for base electrode further contains a solvent. A capacitor body in which a plurality of dielectric layers and internal electrode layers are alternately stacked, a base electrode electrically connected to the internal electrode layer of the capacitor body, and an external electrode provided on the base electrode Provided, the base electrode is a manufacturing method of a chip capacitor including a metal phase containing copper and a glass phase containing phosphorus and oxygen,
Composition for ground electrode containing at least one metal particle selected from the group consisting of phosphorus-containing copper alloy particles, phosphorus-tin-containing copper alloy particles, and phosphorus-tin-nickel-containing copper alloy particles, and glass particles Applying to the capacitor body,
And a step of heat-treating the base electrode composition to form the base electrode.