JP2011057511A - Ceramic electronic part and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide ceramic electronic parts of high reliability by achieving improvement of high temperature load life, and a method for manufacturing the parts. <P>SOLUTION: The ceramic electronic parts include a dielectric layer and an electrode layer, where the dielectric layer 2 is composed of a dielectric ceramic composition containing a compound expressed by ABO<SB>3</SB>(wherein A is at least one selected from Ba, Ca and Sr; and B is at lest one selected from Ti and Zr) and an oxide of rare-earth element; and in the dielectric layer 2, there exists a segregation zone 20 where only oxides of the rare-earth element are segregated, and in the cross section of the dielectric layer 2, the ratio of area occupied by the segregation zone 20 to the visual field area of 1.0×1.0 μm is 0.45-0.90%. The content of the oxide of rare-earth element is preferably 1.0-2.0 mol%. The area ratio of the segregation zone can be controlled by setting the rate of temperature rise during firing to 700-2,000°C/h, for example. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a ceramic electronic component and a manufacturing method thereof, and more particularly to an electronic component with improved reliability and a manufacturing method thereof.

  Ceramic electronic components are widely used as small-sized, high-performance, and high-reliability electronic components, and the number of ceramic electronic components used in electrical and electronic devices is large. In recent years, with the miniaturization and high performance of devices, the demand for further miniaturization, high performance, and high reliability of ceramic electronic components has become increasingly severe.

  In response to such a requirement, Patent Document 1 discloses that the BET value of the raw material powder of barium titanate and the BET value of the raw material powder of the dielectric ceramic composition have a specific relationship, so that the dielectric breakdown voltage, etc. A multilayer ceramic capacitor that improves the reliability of the above is disclosed. However, the multilayer ceramic capacitor disclosed in Patent Document 1 has been insufficient in improving the high-temperature load life.

JP 2006-290675 A

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a highly reliable ceramic electronic component and a method for manufacturing the same, which can improve the high temperature load life.

In order to achieve the above object, a ceramic electronic component according to the present invention comprises:
A ceramic electronic component having a dielectric layer and an electrode layer,
The dielectric layer is a compound represented by the general formula ABO ₃ (A is at least one selected from Ba, Ca and Sr, and B is at least one selected from Ti and Zr); An oxide (R is at least one selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu). A dielectric porcelain composition comprising:
In the dielectric layer, there exists a segregation region where only the oxide of R segregates,
In the cross section of the dielectric layer, the ratio of the area occupied by the segregation region to the visual field area of 1.0 × 1.0 μm is 0.45 to 0.90%.

  In the present invention, a segregation region in which only the R oxide is segregated is formed in the dielectric layer. That is, in the segregation region, the R element is present at a higher concentration than other regions, but the other elements are not present at a higher concentration than the other regions. By setting the area ratio of such a segregation region in the above range, the high temperature load life of the electronic component can be improved, and as a result, the reliability as the electronic component can be improved.

The ceramic electronic component according to the present invention is
A ceramic electronic component having a dielectric layer and an electrode layer,
The dielectric layer is a compound represented by the general formula ABO ₃ (A is at least one selected from Ba, Ca and Sr, and B is at least one selected from Ti and Zr); An oxide (R is at least one selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu). A dielectric porcelain composition comprising:
The oxide of R is contained in an amount of 1.0 to 2.0 mol in terms of R ₂ O _{3 with} respect to 100 mol of the ABO ₃ ,
The dielectric layer has a segregation region in which only the R oxide is segregated.

  The content of the oxide of R in the dielectric ceramic composition is in the above range, and the existence of a segregation region in which only the oxide of R is segregated can improve the high temperature load life. Reliability as an electronic component can be increased.

Preferably, the ABO ₃ raw material powder has a BET specific surface area value of 5.0 to 6.0 m ² / g. By using the raw material powder having a BET specific surface area value in a specific range, a segregation region where only the R oxide is segregated can be easily formed, and the reliability as an electronic component can be improved.

Preferably, the dielectric ceramic composition has an Mg oxide content of 0.5 to 1.5 mol in terms of MgO and an Mn oxide content of 0.1 to 0 in terms of MnO with respect to 100 mol of the ABO _3. 0.3 mol, 0.05 to 0.2 mol of V oxide in terms of V ₂ O ₅ , and 0.5 to 2.0 mol of compound containing Si oxide in terms of SiO ₂ .

  By including a specific amount of the above components, it is possible to easily form a segregation region where only the oxide of R is segregated while improving various characteristics as an electronic component, and to improve the reliability as an electronic component. it can.

  Preferably, R is one selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. That is, the above-described effects can be further enhanced by segregation of one type of R element oxide rather than a plurality of R element oxides.

In addition, a method for manufacturing a ceramic electronic component according to the present invention includes:
A method of manufacturing a ceramic electronic component having a dielectric layer and an electrode layer, the method comprising:
The dielectric layer comprises a compound represented by the general formula ABO ₃ (A is at least one selected from Ba, Ca and Sr, and B is at least one selected from Ti and Zr); An oxide (R is at least one selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu). A dielectric ceramic composition comprising:
Mixing the ABO ₃ raw material powder and the R oxide raw material powder to prepare a mixed raw material powder;
Using the mixed raw material powder to obtain a molded body;
Firing the molded body, and
In the step of firing the molded body, the temperature rising rate is set to 700 to 2000 ° C./hour.

  By doing as described above, it is possible to easily control the existence state of the segregation region where only the oxide of R is segregated. As a result, the high temperature load life of the electronic component can be improved, and a highly reliable electronic component can be obtained.

Preferably, the oxide of R is contained in an amount of 1.0 to 2.0 mol in terms of R ₂ O _{3 with} respect to 100 mol of the ABO ₃ .

Preferably, the ABO ₃ raw material powder has a BET specific surface area value of 5.0 to 6.0 m ² / g.

Preferably, the dielectric ceramic composition has an Mg oxide content of 0.5 to 1.5 mol in terms of MgO and an Mn oxide content of 0.1 to 0 in terms of MnO with respect to 100 mol of the ABO _3. 0.3 mol, 0.05 to 0.2 mol of V oxide in terms of V ₂ O ₅ , and 0.5 to 2.0 mol of compound containing Si oxide in terms of SiO ₂ .

By making the content of the component contained in the dielectric ceramic composition and the BET specific surface area value of the raw material powder of ABO ₃ within the above ranges, the above-described effects can be further enhanced.

  Preferably, R is one selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. The effect mentioned above can further be heightened because one type of oxide of R segregates.

Preferably, in the step of preparing the mixed raw material powder, the surface of the ABO ₃ raw material powder is coated with the raw material powder of the R oxide.

  By doing in this way, formation of the segregation area | region where only the oxide of R segregates can be controlled easily, Furthermore, the area ratio can be easily made into a desired range. As a result, the high temperature load life can be improved, and the reliability as an electronic component can be increased.

FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the presence of segregation regions in the cross section of the dielectric layer of the multilayer ceramic capacitor shown in FIG. FIG. 3 is a schematic diagram for explaining a method of calculating the average concentration of the R element.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

Multilayer ceramic capacitor 1
As shown in FIG. 1, a multilayer ceramic capacitor 1 according to an embodiment of the present invention includes a capacitor element body 10 having a configuration in which dielectric layers 2 and internal electrode layers 3 are alternately stacked. The internal electrode layers 3 are laminated so that the end faces are alternately exposed on the surfaces of the two opposite ends of the capacitor element body 10. The pair of external electrodes 4 are formed at both ends of the capacitor element body 10 and are connected to the exposed end surfaces of the alternately arranged internal electrode layers 3 to constitute a capacitor circuit.

  The shape of the capacitor element body 10 is not particularly limited, but is usually a rectangular parallelepiped as shown in FIG. Moreover, there is no restriction | limiting in particular also in the dimension, What is necessary is just to set it as a suitable dimension according to a use.

Dielectric layer 2
The dielectric layer 2 includes a compound represented by the general formula ABO ₃ (A is at least one selected from Ba, Ca and Sr, and B is at least one selected from Ti and Zr); An oxide (R is at least one selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu). It consists of a dielectric ceramic composition.

In the present embodiment, for example, BaTiO ₃ , CaTiO ₃ , SrTiO _3, or a mixture thereof is preferable as ABO ₃ . In particular, BaTiO ₃ (preferably represented by the composition formula Ba _m TiO _{2 + m} , m is 0.995 ≦ m ≦ 1.010, and the ratio of Ba to Ti is 0.995 ≦ Ba / Ti ≦ 1.010. Can be suitably used.

The oxide of R is preferably contained in an amount of 1.0 to 2.0 mol, more preferably 1.4 to 1.9 mol in terms of R ₂ O _{3 with} respect to 100 mol of ABO ₃ . If the content of R oxide is too much or too little, the high temperature load life tends to deteriorate. The R element may be a plurality of elements, but in the present embodiment, it is preferably one kind of element. The R element is particularly preferably a Y element.

  The dielectric ceramic composition according to the present embodiment may further contain other components according to desired characteristics.

Specifically, it is preferable that the dielectric ceramic composition according to the present embodiment further contains an oxide of Mg. The content of the Mg oxide is preferably 0.5 to 1.5 mol, more preferably 0.6 to 0.8 mol in terms of MgO with respect to 100 mol of ABO ₃ . If the content of the Mg oxide is too small, the high temperature load life tends to deteriorate. Conversely, if it is too large, Mg segregates in the segregation region described later, and as a result, the high temperature load life tends to deteriorate. is there.

Moreover, it is preferable that the dielectric ceramic composition according to the present embodiment further contains an oxide of Mn. The content of the Mn oxide is preferably 0.1 to 0.3 mol, more preferably 0.15 to 0.25 mol in terms of MnO with respect to 100 mol of ABO ₃ . If the content of the Mn oxide is too small, the high temperature load life tends to deteriorate, and conversely if too much, Mn segregates in the segregation region described later, and as a result, the high temperature load life tends to deteriorate. is there.

The dielectric ceramic composition according to this embodiment preferably further contains an oxide of V. The content of the V oxide is preferably 0.05 to 0.2 mol, more preferably 0.13 to 0.18 mol in terms of V ₂ O _{5 with} respect to 100 mol of ABO ₃ . If the content of the V oxide is too small, the high temperature load life tends to deteriorate. Conversely, if it is too large, V segregates in the segregation region described later, and as a result, the high temperature load life tends to deteriorate. is there.

Moreover, it is preferable that the dielectric ceramic composition according to the present embodiment further contains a compound containing a Si oxide. The content of the compound containing an oxide of _Si, relative to ABO 3 100 moles, in terms of SiO _2, preferably 0.5 to 2.0 moles, more preferably 1.0 to 1.6 moles. If the content of the above compound is too small, the high temperature load life tends to be deteriorated. On the other hand, if the content is too large, Si is segregated in the segregation region described later, and as a result, the high temperature load life tends to be deteriorated.

The compound containing an oxide of Si may be SiO ₂ alone, but in this embodiment, (Ba, Ca) SiO ₃ which is a composite oxide is preferable.

Segregation region 20
In the present embodiment, as shown in FIG. 2, the dielectric layer 2 includes dielectric particles 12 and a segregation region 20 where only an oxide of R is segregated. The presence of such a segregation region in which only the oxide of R is segregated can improve the high-temperature load life of the capacitor, and as a result, improve the reliability.

The dielectric layer 2 also includes a region (phase) other than the segregation region, and the phase may contain an element that constitutes ABO ₃ or an R element. Mn, V and Si may be contained. In the present embodiment, as shown in FIG. 2, there are dielectric particles 12 containing ABO ₃ as a main component and having an R element as a solid solution.

The “segregation region where only the R oxide is segregated” means a region in which only the R oxide exists in a higher concentration than the other regions. Therefore, an element constituting ABO ₃ may be present in the segregation region. Further, Mg, Mn, V, Si and the like may be present, but the oxides of these elements need not be segregated. For example, a region where both the oxide of R and MgO are segregated (present at a high concentration) is not a segregated region in the present invention. Thus, when the oxide of R and the oxide of elements other than the R element are segregated, the high temperature load life tends to deteriorate, which is not preferable. Since ABO ₃ is the main component of the dielectric particles, there is no “segregation region where only ABO ₃ is segregated”.

  The segregation region where only the oxide of R is segregated is determined by visual observation of the segregation region and other phases in the scanning electron microscope (SEM) photograph of the cross section of the dielectric layer 2 based on the difference in contrast. Although the area ratio may be calculated, in this embodiment, the presence of the segregation region and the area ratio are determined as follows.

  First, the cross section of the dielectric layer 2 is observed with a scanning transmission electron microscope (STEM), and the attached energy dispersive X-ray spectrometer is used to measure a field area of 1.0 × 1.0 μm with respect to R. Obtain element mapping images for elements and other elements.

  Next, a predetermined number (for example, 5 or more) of dielectric particles are observed with a STEM and measured using an attached energy dispersive X-ray spectrometer. Specifically, as shown in FIG. 3, point analysis is performed on a straight line passing through the approximate center of the dielectric particle, and the R element (and the element) in the particle is calculated from the concentration distribution of the obtained R element (and other elements). The average concentration of other elements is calculated.

  The mapping image (1.0 × 1.0 μm) for the R element and other elements obtained above is subjected to image processing, so that the average concentration of the R element (and other elements) exceeds 1/3. The area is divided into an area having an average density of 1/3 or less. That is, a region where the average concentration exceeds 1/3 is defined as a region where oxides of the respective elements are segregated. Of the regions where the oxide of R is segregated, the region where only the oxide of R is segregated is defined as the “segregation region” in the present invention. If it does in this way, in the bright field image by SEM, it will come to correspond well with the boundary of the segregation area | region observed as a difference of contrast, and the other phase.

  Next, the area of the segregated region subjected to image processing is calculated, and the area ratio with respect to the visual field area of 1.0 × 1.0 μm is calculated. The area ratio is 0.45 to 0.90%, preferably 0.60 to 0.85%.

  By controlling this area ratio, the high temperature load life can be improved, and even if the area ratio is too small or too large, the high temperature load life tends to deteriorate.

  The thickness of the dielectric layer 2 is not particularly limited, but is preferably 5 μm or less per layer. Although the minimum of thickness is not specifically limited, For example, it is about 0.5 micrometer.

  The number of laminated dielectric layers 2 is not particularly limited, but is preferably 20 or more, more preferably 50 or more, and particularly preferably 100 or more. The upper limit of the number of stacked layers is not particularly limited, but is about 2000, for example.

Internal electrode layer 3
The conductive material contained in the internal electrode layer 3 is not particularly limited, but a relatively inexpensive base metal can be used because the constituent material of the dielectric layer 2 has reduction resistance. As the base metal used as the conductive material, Ni or Ni alloy is preferable. The Ni alloy is preferably an alloy of Ni and one or more elements selected from Mn, Cr, Co and Al, and the Ni content in the alloy is preferably 95% by weight or more. In addition, in Ni or Ni alloy, various trace components, such as P, may be contained about 0.1 wt% or less. The thickness of the internal electrode layer 3 may be appropriately determined according to the application and the like, but is usually about 0.1 to 3 μm, particularly preferably about 0.2 to 2.0 μm.

External electrode 4
The conductive material contained in the external electrode 4 is not particularly limited, but in the present invention, inexpensive Ni, Cu, and alloys thereof can be used. The thickness of the external electrode 4 may be appropriately determined according to the application and the like, but is usually preferably about 10 to 50 μm.

Manufacturing Method of Multilayer Ceramic Capacitor 1 The multilayer ceramic capacitor 1 of the present embodiment is the same as a conventional multilayer ceramic capacitor. After producing a green chip by a normal printing method or a sheet method using a paste and firing it, It is manufactured by printing or transferring an external electrode and firing. Hereinafter, the manufacturing method will be specifically described.

  First, a dielectric material (mixed material powder) contained in the dielectric layer paste is prepared, and this is made into a paint to prepare a dielectric layer paste.

  The dielectric layer paste may be an organic paint obtained by kneading a dielectric material and an organic vehicle, or may be a water-based paint.

As the dielectric material, first, an ABO ₃ material and an R oxide material are prepared. As these raw materials, oxides of the above-described components, mixtures thereof, and composite oxides can be used. In addition, various compounds that become the above-described oxides or composite oxides by firing, such as carbonates and oxalic acid. They can be appropriately selected from salts, nitrates, hydroxides, organometallic compounds, and the like, and can also be used as a mixture.

ABO ₃ raw materials are produced by various methods such as those produced by various liquid phase methods (for example, oxalate method, hydrothermal synthesis method, alkoxide method, sol-gel method, etc.) in addition to the so-called solid phase method. Can be used.

Moreover, the BET specific surface area value of the ABO ₃ raw material is preferably 5.0 to 6.0 m ² / g, more preferably 5.4 to 5.8 m ² / g. By using the raw material of ABO ₃ having such a BET specific surface area value and the raw material of the oxide of R, the R element that did not contribute to the diffusion into the dielectric particles is desired alone in the dielectric layer. It can be made to precipitate in this state. That is, it is possible to suitably control the existence state of the segregation region in which only the R oxide is segregated. As a result, it becomes easy to make the area ratio of the segregation region within the range of the present invention.

Alternatively, the surface of the ABO ₃ raw material powder may be coated with at least an R oxide raw material powder. The method for coating is not particularly limited, and a known method may be used. For example, the raw material powder of the oxide of R element may be made into a solution and heat-treated for coating. By using such coated powder, it is possible to efficiently form a segregation region in which only the R oxide is segregated. Further, the raw material powder of the other components, may be coated on the surface of the raw material powder of ABO _3.

  What is necessary is just to determine content of each compound in a dielectric raw material so that it may become a composition of the above-mentioned dielectric ceramic composition after baking. In the state before forming a paint, the particle size of the dielectric material is usually about 0.1 to 1 μm in average particle size.

  An organic vehicle is obtained by dissolving a binder in an organic solvent. The binder used for the organic vehicle is not particularly limited, and may be appropriately selected from usual various binders such as ethyl cellulose and polyvinyl butyral. The organic solvent to be used is not particularly limited, and may be appropriately selected from various organic solvents such as terpineol, butyl carbitol, acetone, toluene, and the like according to a method to be used such as a printing method or a sheet method.

  Further, when the dielectric layer paste is used as a water-based paint, a water-based vehicle in which a water-soluble binder or a dispersant is dissolved in water and a dielectric material may be kneaded. The water-soluble binder used for the water-based vehicle is not particularly limited, and for example, polyvinyl alcohol, cellulose, water-soluble acrylic resin, etc. may be used.

  The internal electrode layer paste is obtained by kneading the above-mentioned organic vehicle with various conductive metals and alloys as described above, or various oxides, organometallic compounds, resinates, etc. that become the above-mentioned conductive materials after firing. Prepare. The internal electrode layer paste may contain a common material. The common material is not particularly limited, but preferably has the same composition as the main component.

  The external electrode paste may be prepared in the same manner as the internal electrode layer paste described above.

  There is no restriction | limiting in particular in content of the organic vehicle in each above-mentioned paste, For example, what is necessary is just about 1-5 weight% of binders, for example, about 10-50 weight% of binders. Each paste may contain additives selected from various dispersants, plasticizers, dielectrics, insulators, and the like as necessary. The total content of these is preferably 10% by weight or less.

  When the printing method is used, the dielectric layer paste and the internal electrode layer paste are printed and laminated on a substrate such as PET, cut into a predetermined shape, and then peeled from the substrate to obtain a green chip.

  When the sheet method is used, a green sheet is formed using a dielectric layer paste, an internal electrode layer paste is printed thereon to form an internal electrode pattern, and these are stacked to form a green chip. .

  Before firing, the green chip is subjected to binder removal processing. As binder removal conditions, the temperature rising rate is preferably 5 to 300 ° C./hour, the holding temperature is preferably 180 to 400 ° C., and the temperature holding time is preferably 0.5 to 24 hours. The binder removal atmosphere is air or a reducing atmosphere.

  In the firing of the green chip, the rate of temperature rise is preferably 700 to 2000 ° C./hour, more preferably 1000 to 1700 ° C./hour. By setting such a very high temperature increase rate, it is possible to suitably control the existence state of the segregation region in which only the R oxide is segregated. As a result, it becomes easy to make the area ratio of the segregation region within the range of the present invention.

  The holding temperature at the time of firing is preferably 1300 ° C. or less, more preferably 1200 to 1300 ° C., and the holding time is preferably 0.5 to 8 hours, more preferably 2 to 3 hours. If the holding temperature is less than the above range, the densification is insufficient. Reduction of the body porcelain composition is likely to occur.

The firing atmosphere is preferably a reducing atmosphere. As the atmosphere gas, for example, a mixed gas of N ₂ and H ₂ can be used by humidification.

In addition, the oxygen partial pressure during firing may be appropriately determined according to the type of the conductive material in the internal electrode layer paste, but when a base metal such as Ni or Ni alloy is used as the conductive material, The oxygen partial pressure is preferably 10 ⁻¹⁴ to 10 ⁻¹⁰ MPa. When the oxygen partial pressure is less than the above range, the conductive material of the internal electrode layer may be abnormally sintered and may be interrupted. Further, when the oxygen partial pressure exceeds the above range, the internal electrode layer tends to be oxidized. The temperature lowering rate is preferably 50 to 500 ° C./hour.

  After firing in a reducing atmosphere, the capacitor element body is preferably annealed. Annealing is a process for re-oxidizing the dielectric layer, and thereby the IR life (insulation resistance life) can be remarkably increased, so that the reliability is improved.

The oxygen partial pressure in the annealing atmosphere is preferably 10 ⁻⁹ to 10 ⁻⁵ MPa. When the oxygen partial pressure is less than the above range, it is difficult to re-oxidize the dielectric layer, and when it exceeds the above range, oxidation of the internal electrode layer tends to proceed.

  The holding temperature at the time of annealing is preferably 1100 ° C. or less, and particularly preferably 1000 to 1100 ° C. When the holding temperature is lower than the above range, the dielectric layer is not sufficiently oxidized, so that the IR is low and the IR life tends to be short. On the other hand, if the holding temperature exceeds the above range, not only the internal electrode layer is oxidized and the capacity is lowered, but the internal electrode layer reacts with the dielectric substrate, the capacity temperature characteristic is deteriorated, the IR is lowered, the IR Life is likely to decrease. Note that annealing may be composed of only a temperature raising process and a temperature lowering process. That is, the temperature holding time may be zero. In this case, the holding temperature is synonymous with the maximum temperature.

As other annealing conditions, the temperature holding time is preferably 0 to 20 hours, more preferably 2 to 4 hours, and the cooling rate is preferably 50 to 500 ° C./hour, more preferably 100 to 300 ° C./hour. . Further, as the annealing atmosphere gas, for example, humidified N ₂ gas or the like is preferably used.

In the above-described binder removal processing, firing and annealing, for example, a wetter or the like may be used to wet the N ₂ gas or mixed gas. In this case, the water temperature is preferably about 5 to 75 ° C.

  The binder removal treatment, firing and annealing may be performed continuously or independently.

  The capacitor element main body obtained as described above is subjected to end face polishing, for example, by barrel polishing or sand blasting, and the external electrode paste is applied and fired to form the external electrode 4. Then, if necessary, a coating layer is formed on the surface of the external electrode 4 by plating or the like.

  The multilayer ceramic capacitor of this embodiment manufactured in this way is mounted on a printed circuit board or the like by soldering or the like and used for various electronic devices.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to the embodiment mentioned above at all, and can be variously modified within the range which does not deviate from the summary of this invention.

  In the above-described embodiment, the multilayer ceramic capacitor is exemplified as the electronic component according to the present invention. However, the electronic component according to the present invention is not limited to the multilayer ceramic capacitor, and any electronic component having the above configuration may be used. good.

  Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples.

Example 1
First, BaTiO ₃ powder was prepared as an ABO ₃ raw material, and Y ₂ O ₃ powder was prepared as an R oxide raw material. MgCO ₃ powder as a raw material for Mg oxide MnO powder as a raw material for Mn oxide, V ₂ O ₅ powder as a raw material for V oxide, and (Ba, Ca) SiO ₃ powder as a sintering aid were prepared. The BET specific surface area value of the BaTiO ₃ powder was 5.5 m ² / g. Further, (Ba, Ca) SiO ₃ was prepared by wet-mixing BaCO ₃ , CaCO ₃ and SiO ₂ by a ball mill, followed by drying and firing in the air by a ball mill.

Next, each raw material powder prepared above was wet mixed and pulverized in a ball mill for 10 hours and dried to obtain a mixed raw material powder. Incidentally, MgCO _3, after firing, and thus included in the dielectric ceramic composition as MgO.

  Subsequently, the obtained mixed raw material powder: 100 parts by weight, polyvinyl butyral resin: 10 parts by weight, dioctyl phthalate (DOP) as a plasticizer: 5 parts by weight, and alcohol as a solvent: 100 parts by weight with a ball mill The mixture was made into a paste to obtain a dielectric layer paste.

  In addition to the above, Ni particles: 44.6 parts by weight, terpineol: 52 parts by weight, ethyl cellulose: 3 parts by weight, and benzotriazole: 0.4 parts by weight are kneaded with three rolls to obtain a slurry. To prepare an internal electrode layer paste.

  Then, using the dielectric layer paste prepared above, a green sheet was formed on the PET film so that the thickness after drying was 2 μm. Next, the electrode layer was printed in a predetermined pattern using the internal electrode layer paste thereon, and then the sheet was peeled off from the PET film to produce a green sheet having the electrode layer. Next, a plurality of green sheets having electrode layers were laminated and pressure-bonded to obtain a green laminated body, and the green laminated body was cut into a predetermined size to obtain a green chip.

  Next, the obtained green chip was subjected to binder removal treatment, firing and annealing under the following conditions to obtain a multilayer ceramic fired body.

  The binder removal treatment conditions were temperature rising rate: 25 ° C./hour, holding temperature: 260 ° C., temperature holding time: 8 hours, and atmosphere: in the air.

The firing conditions were a heating rate of 2000 ° C./hour, a holding temperature of 1200 ° C., and a holding time of 1 hour. The cooling rate was 2000 ° C./hour. The atmospheric gas was a humidified N ₂ + H ₂ mixed gas, and the oxygen partial pressure was 10 ⁻¹² MPa.

The annealing conditions were: temperature rising rate: 200 ° C./hour, holding temperature: 1000 ° C., temperature holding time: 2 hours, temperature falling rate: 200 ° C./hour, atmospheric gas: humidified N ₂ gas (oxygen partial pressure: 10 ⁻⁷ MPa).

  A wetter was used for humidifying the atmospheric gas during firing and annealing.

  Next, after polishing the end face of the obtained multilayer ceramic fired body by sandblasting, Cu was applied as an external electrode to obtain a sample of the multilayer ceramic capacitor shown in FIG. The size of the obtained capacitor sample is 3.2 mm × 1.6 mm × 0.6 mm, the thickness of the dielectric layer is 1.5 μm, the thickness of the internal electrode layer is 1.0 μm, and the dielectric sandwiched between the internal electrode layers The number of layers was 200.

  For the obtained capacitor sample, the segregation region was observed and the high temperature load life was measured by the methods described below.

Observation of segregation region STEM observation is performed on the cut surface of the dielectric layer of the capacitor sample, and the range of the visual field of 1.0 × 1.0 μm is measured using an energy dispersive X-ray spectrometer (STEM-EDX) attached to the STEM. Element mapping of the Y element was performed.

Next, five randomly extracted particles are observed with a scanning transmission electron microscope (STEM), and point analysis is performed on a straight line passing through the approximate center of each surface diffusion particle by energy dispersive X-ray spectroscopy. Then, the X-ray spectrum of the Y element was measured. From the obtained X-ray spectrum, the average concentration of the Y element in the particles was calculated. The mapping image for the Y element obtained above was subjected to image processing so that the region where the average concentration of the Y element exceeds 1/3 is the region where the Y element is segregated. Further, other elements (Mg, Mn, V, Ba, Ca, Si) were similarly measured and image-processed, but any of MgO, MnO, V ₂ O ₅ and (Ba, Ca) SiO ₃ was used. No segregation region was observed.

Next, the area of the segregated region of Y ₂ O ₃ was calculated from the image after the image processing with respect to the visual field area of 1.0 × 1.0 μm. In addition, the segregation area obtained by the above image processing was in good agreement with the segregation area that can be visually determined from the SEM observation photograph. The results are shown in Table 1.

The high temperature load life was evaluated by measuring the life time of a capacitor sample at a high temperature load at 200 ° C. with a DC voltage applied under an electric field of 6 V / μm. In this example, the time from the start of application until the insulation resistance drops by an order of magnitude was defined as the lifetime. In this example, the above evaluation was performed on 20 capacitor samples, and the average value was defined as the high temperature load life. The evaluation criterion was 80 hours or more. The results are shown in Table 1.

  From Table 1, when the area ratio of the segregation region is within the range of the present invention (sample numbers 3 to 7), it can be confirmed that the high-temperature load life is good and the reliability is improved.

Example 2
A multilayer ceramic capacitor sample was prepared in the same manner as Sample No. 5 in Example 1 except that the BET specific surface area value of the BaTiO ₃ powder was changed to the value shown in Table 2, and the same characteristic evaluation as in Example 1 was performed. It was. The results are shown in Table 2.

From Table 2, BaTiO ₃ BET specific surface area value of the powder by within the preferred range of the present invention (Sample Nos. 13 to 15), the area ratio of the segregation area can be confirmed that can control.

Example 3
A multilayer ceramic capacitor sample was prepared in the same manner as in Example 1 except that the content of Y ₂ O ₃ was changed to the value shown in Table 3, and the same characteristic evaluation as in Example 1 was performed. The results are shown in Table 3. The amount of other components added is 100 mol of BaTiO ₃ , MgCO ₃ is 0.8 mol in terms of MgO, MnO is 0.25 mol, V ₂ O ₅ is 0.16 mol, (Ba, Ca ) SiO ₃ was 1.2 mol in terms of SiO ₂ . This added amount is the content in the dielectric layer after firing.

From Table 3, when the content of Y ₂ O ₃ is within the range of the present invention (sample numbers 23 to 25), it can be confirmed that the high-temperature load life is good and the reliability is improved.

Example 4
A multilayer ceramic capacitor sample was prepared in the same manner as in Example 1 except that the heating rate during firing was set to the values shown in Table 4, and the same characteristic evaluation as in Example 1 was performed. The results are shown in Table 4.

From Table 4, when the rate of temperature increase is within the range of the present invention (sample numbers 33 to 37), a segregation region where only Y ₂ O ₃ is segregated is formed, and the high temperature load life is improved and the reliability is improved. It can be confirmed that the performance is improved.

Example 5
A sample of the multilayer ceramic capacitor was prepared in the same manner as in Example 1 except that the contents of the compound containing Mg oxide, Mn oxide, V oxide and Si oxide were changed to the values shown in Table 5. The same characteristic evaluation as in Example 1 was performed. The results are shown in Table 5.

From Table 5, when the content of each component is within the preferred range of the present invention (sample numbers 42 to 45, 48 to 51, 54 to 57, 60 to 63), only Y ₂ O ₃ is segregated. It can be confirmed that the segregated region is formed within the scope of the present invention, the high temperature load life is improved, and the reliability is improved.

Example 6
A multilayer ceramic capacitor sample was prepared in the same manner as in Example 1 except that the Y ₂ O ₃ content, the rate of temperature increase, and the BET specific surface area were changed to the values shown in Table 6. Characterization was performed. The results are shown in Table 6.

From Table 6, when the content of Y ₂ O ₃ , the temperature increase rate, and the BET specific surface area are within the preferable ranges of the present invention (sample numbers 73 to 76), only Y ₂ O ₃ is segregated. It can be confirmed that the segregation region is formed within the scope of the present invention, the high temperature load life is improved, and the reliability is improved.

DESCRIPTION OF SYMBOLS 1 ... Multilayer ceramic capacitor 2 ... Dielectric layer 3 ... Internal electrode layer 4 ... External electrode 10 ... Capacitor element body 12 ... Dielectric particle 20 ... Segregation region

Claims (13)

A ceramic electronic component having a dielectric layer and an electrode layer,
The dielectric layer is a compound represented by the general formula ABO ₃ (A is at least one selected from Ba, Ca and Sr, and B is at least one selected from Ti and Zr); An oxide (R is at least one selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu). A dielectric porcelain composition comprising:
In the dielectric layer, there exists a segregation region where only the oxide of R segregates,
In the cross section of the dielectric layer, the ratio of the area occupied by the segregation region to the visual field area of 1.0 × 1.0 μm is 0.45 to 0.90%. The ceramic electronic component according to claim 1, wherein the R oxide is contained in an amount of 1.0 to 2.0 mol in terms of R ₂ O _{3 with} respect to 100 mol of the ABO ₃ . A ceramic electronic component having a dielectric layer and an electrode layer,
The dielectric layer is a compound represented by the general formula ABO ₃ (A is at least one selected from Ba, Ca and Sr, and B is at least one selected from Ti and Zr); An oxide (R is at least one selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu). A dielectric porcelain composition comprising:
The oxide of R is contained in an amount of 1.0 to 2.0 mol in terms of R ₂ O _{3 with} respect to 100 mol of the ABO ₃ ,
The ceramic electronic component according to claim 1, wherein a segregation region in which only the oxide of R is segregated exists in the dielectric layer.   4. The ceramic electronic component according to claim 3, wherein a ratio of an area occupied by the segregation region is 0.45 to 0.90% with respect to a visual field area of 1.0 × 1.0 μm in a cross section of the dielectric layer. The ceramic electronic component according to claim 1, wherein the ABO ₃ raw material powder has a BET specific surface area value of 5.0 to 6.0 m ² / g. In the dielectric ceramic composition, the oxide of Mg is 0.5 to 1.5 mol in terms of MgO and the oxide of Mn is 0.1 to 0.3 mol in terms of MnO with respect to 100 mol of the ABO _3. The oxide of V contains 0.05 to 0.2 mol in terms of V ₂ O ₅ , and the compound containing an oxide of Si contains 0.5 to 2.0 mol in terms of SiO _2. A ceramic electronic component according to any one of the above.   The R is one selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. A ceramic electronic component according to any one of the above. A method of manufacturing a ceramic electronic component having a dielectric layer and an electrode layer, the method comprising:
The dielectric layer comprises a compound represented by the general formula ABO ₃ (A is at least one selected from Ba, Ca and Sr, and B is at least one selected from Ti and Zr); An oxide (R is at least one selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu). A dielectric ceramic composition comprising:
Mixing the ABO ₃ raw material powder and the R oxide raw material powder to prepare a mixed raw material powder;
Obtaining a molded body using the mixed raw material powder;
Firing the molded body, and
A method of manufacturing a ceramic electronic component, wherein, in the step of firing the molded body, a temperature rising rate is set to 700 to 2000 ° C./hour. The method for producing a ceramic electronic component according to claim 8, wherein the R oxide is contained in an amount of 1.0 to 2.0 mol in terms of R ₂ O _{3 with} respect to 100 mol of the ABO ₃ . The method for producing a ceramic electronic component according to claim 8 or 9, wherein the ABO ₃ raw material powder has a BET specific surface area value of 5.0 to 6.0 m ² / g. The dielectric ceramic composition further includes an oxide of Mg, an oxide of Mn and an oxide of V, and a sintering aid mainly composed of Si,
With respect to 100 mol of ABO ₃ , the oxide of Mg is 0.5 to 1.5 mol, the oxide of Mn is 0.1 to 0.3 mol, and the oxide of V is 0.05 to 0 The method for producing a ceramic electronic component according to any one of claims 8 to 10, wherein 0.2 mol and the sintering aid are contained in an amount of 0.5 to 2.0 mol.   The R is one selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. A method for producing a ceramic electronic component according to claim 1. The method of manufacturing a ceramic electronic component according to any one of claims 8 to 12, wherein in the step of preparing the mixed raw material powder, a surface of the ABO ₃ raw material powder is coated with at least the raw material powder of the R oxide.

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