JP2011046605A - Electronic component and dielectric ceramic composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic component such as a multilayer capacitor wherein the temperature characteristic of the electrostatic capacity is capable of satisfying both the X7R characteristics (EIA standard) and the B characteristics (EIAJ standard), the electrostatic capacity and the insulation resistance show little voltage dependency, the insulation breakdown resistance is excellent and Ni or a Ni alloy can be used as an internal electrode layer, a dielectric ceramic composition suitably used as a dielectric layer of the electronic component, and a method for producing the same. <P>SOLUTION: The dielectric ceramic composition comprises barium titanate and component M, wherein M is at least one selected from the group consisting of manganese oxide, iron oxide, cobalt oxide and nickel oxide, as main components, and has a ferroelectric phase region, wherein the concentration of component M in the ferroelectric phase region changes from the outside toward the center. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electronic component such as a multilayer capacitor, a dielectric ceramic composition suitable for use as a dielectric layer of the electronic component, and a method for producing the same.

  Multilayer ceramic capacitors are widely used as small-sized, large-capacity, high-reliability electronic components, and are widely used in electrical equipment and electronic equipment. In recent years, with the miniaturization and high performance of devices, the demand for further miniaturization, larger capacity, lower cost, and higher reliability for multilayer ceramic capacitors has become increasingly severe.

  One of the key technologies for reducing the price is to use relatively inexpensive Ni or Ni alloy as an internal electrode without using expensive Pd or Pd alloy. The key technology for downsizing and increasing the capacity is to make the dielectric layer thinner and multi-layered.

When the thickness of the dielectric layer is reduced, the electric field strength acting on the dielectric layer when a DC voltage is applied increases, and the phenomenon that the capacitance and insulation resistance decrease accordingly is particularly high dielectric dielectric. This is remarkable in porcelain compositions. As a conventional report on the DC voltage dependency of capacitance, that is, DC bias characteristics, a compound such as Bi ₂ O ₃ , TiO ₂ , SnO ₂ , ZrO ₂ and a rare earth element are added to barium titanate as a main component. Those added as ingredients are widely known. However, when applied as a multilayer capacitor containing a dielectric ceramic composition containing these compounds as subcomponents as a dielectric layer, Pd of the internal electrode layer reacts with subcomponent compounds (for example, Bi ₂ O ₃ ). The characteristics as a capacitor are insufficient. For this reason, it is necessary to use Pt or Au more expensive than Pd as the internal electrode layer.

Further, as a dielectric porcelain composition not containing a compound such as Bi ₂ O ₃ , Nb ₂ O ₅ , Co ₂ O ₃ , Nd ₂ O ₅ , MnO ₂ , and SiO ₂ are added to the main component barium titanate. A dielectric ceramic composition containing it as a component is known (Japanese Patent Laid-Open No. 6-203630). A multilayer capacitor using the dielectric ceramic composition as a dielectric layer and a 30% Ag-70% Pd alloy as an internal electrode has a temperature change rate TCC of the capacitance that satisfies the X7R characteristic of the EIA standard, and a DC bias. The capacitance change rate ΔC / C when an electric field is applied at 2 kV / mm is within −30%. However, this dielectric ceramic composition has been difficult to apply to a multilayer capacitor having Ni as an internal electrode layer.

  In addition, as shown in Patent Document 1, in order to improve the dielectric breakdown voltage, it has a core-shell structure crystal grain, and an additive such as Mn is distributed substantially uniformly throughout the grain boundary to the center of the crystal grain. A barium titanate-based dielectric porcelain composition is known. However, in such a dielectric ceramic composition, the dielectric constant is not sufficient and the temperature change rate TCC of the capacitance does not necessarily satisfy the X7R characteristic of the EIA standard.

Japanese Patent Laid-Open No. 10-330160

  The present invention has been made in view of such a situation, and can satisfy both the X7R characteristic (EIA standard) and the B characteristic (EIAJ standard) indicating the temperature characteristic of the electrostatic capacity, and the electrostatic capacity and the insulation. Resistant voltage dependence, excellent dielectric breakdown resistance, and suitable for use as an electronic component such as a multilayer capacitor in which Ni or Ni alloy can be used as an internal electrode layer, and as a dielectric layer of the electronic component It is an object to provide a product and a method for manufacturing the product.

  As a result of intensive studies to achieve the above object, the inventor of the present invention is a dielectric ceramic composition mainly composed of barium titanate and an M component and having a ferroelectric phase region. It has been found that when the concentration of the M component changes from the outside toward the center, it has excellent characteristics, and the present invention has been completed.

That is, the dielectric ceramic composition according to the present invention is
Ferroelectric phase mainly composed of barium titanate and M component (where M is at least one component selected from the group consisting of manganese oxide, iron oxide, cobalt oxide and nickel oxide) A dielectric ceramic composition having a region,
The concentration of the M component in the ferroelectric phase region changes from the outside toward the center.

It is preferable that the concentration of the M component in the ferroelectric phase region is higher on the outer side than in the vicinity of the center of the region.
The ferroelectric phase region is composed of an outer ferroelectric phase region and an inner ferroelectric phase region, and the M component of the outer ferroelectric phase region is compared with the inner ferroelectric phase region. A high concentration is preferred. In this case, it is more preferable that the inner ferroelectric phase region hardly contains the M component.

  In the dielectric ceramic composition of the present invention, generally, a diffusion phase region exists outside the ferroelectric phase region.

The method for producing a dielectric ceramic composition according to the present invention includes:
Calcination of barium titanate (A) and raw material of M component (where M is at least one component selected from the group consisting of manganese oxide, iron oxide, cobalt oxide and nickel oxide) Process,
A step of firing a mixture obtained by mixing the compound obtained in the calcining step and another barium titanate (B).

The calcining temperature is preferably 1000 to 1300 ° C.
The firing can be performed in a reducing atmosphere.

  The molar ratio (M / A) of the M component to the barium titanate (A) before calcination is preferably 0.0010 to 0.0120, more preferably 0.0020 to 0.0080. Moreover, the molar ratio (B / A) of post-added barium titanate (B) to barium titanate (A) before calcination is preferably 0.05 to 5.00, more preferably 0.10 to 1. .00.

  The electronic component according to the present invention is an electronic component having a dielectric layer, wherein the dielectric layer is composed of the dielectric ceramic composition.

In the present invention, the ferroelectric phase region refers to the inside of the portion of the crystal grain where the boundary is observed as a result of observing the microstructure of the dielectric ceramic composition with a transmission electron microscope (TEM). The ferroelectricity of barium titanate (BaTiO ₃ ) is derived from the dipole moment generated by the displacement of Ti ions. When atoms other than Ti atoms are dissolved in barium titanate, the dielectric constant decreases, and electrostatic properties are further reduced. Capacitance and insulation resistance become insensitive to the applied voltage, and the ferroelectricity decreases.

  Therefore, it is considered that the inner ferroelectric phase having a low M component concentration contributes to the improvement of the dielectric constant, and the outer ferroelectric phase having a high M component concentration has a low ferroelectricity. The ferroelectric layer region in the dielectric ceramic composition of the present invention is a combination of two or more kinds of such ferroelectric phases. As a result, the dielectric constant is high and the temperature dependence of the capacitance is small. In addition, it is considered that it is possible to provide a dielectric ceramic composition having a smaller voltage dependency of capacitance and insulation resistance.

  In the ferroelectric phase region, if the concentration of the M component is relatively low and has a uniform distribution, the dielectric ceramic composition has a high dielectric constant but a large voltage dependency. There is a point. Also, in the ferroelectric phase region, when the concentration of the M component is relatively high and has a uniform distribution, the dielectric ceramic composition is less voltage dependent but has a lower dielectric constant. There is a problem.

FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention. FIG. 2 is a TEM photograph of a dielectric ceramic composition according to an example of the present invention. FIG. 3 is a graph showing the MnO distribution in the ferroelectric phase region in the photograph shown in FIG. 4 (A) and 4 (B) are graphs showing temperature characteristics of Example 1 and Comparative Example 4 in the examples of the present invention. FIGS. 5A and 5B are graphs showing the voltage characteristics of Examples 1 and 18 in the example of the present invention.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention, FIG. 2 is a TEM photograph of a dielectric ceramic composition according to an embodiment of the present invention, and FIG. 3 is a ferroelectric body in the photograph shown in FIG. FIG. 4 (A) and FIG. 4 (B) are graphs showing the temperature characteristics of Example 1 and Comparative Example 4 in the examples of the present invention, FIG. 5 (A) and FIG. B) is a graph showing the voltage characteristics of Examples 1 and 18 in the example of the present invention.

Multilayer Ceramic Capacitor 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. At both ends of the capacitor element body 10, a pair of external electrodes 4 are formed which are electrically connected to the internal electrode layers 3 arranged alternately in the element body 10. The shape of the capacitor element body 10 is not particularly limited, but is usually a rectangular parallelepiped shape. Also, there is no particular limitation on the dimensions, and it may be an appropriate dimension according to the application. Usually, (0.6 to 5.6 mm) × (0.3 to 5.0 mm) × (0.3 ˜1.9 mm).

  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.

Dielectric layer 2
The dielectric layer 2 contains the dielectric ceramic composition of the present invention.
The dielectric ceramic composition of the present invention comprises:
Barium titanate (BaTiO ₃ ) and M component (where M is at least selected from the group consisting of manganese oxide (MnO), iron oxide (FeO), cobalt oxide (CoO) and nickel oxide (NiO)) A dielectric ceramic composition having a ferroelectric phase region, the main component of which is one or more components),
The concentration of the M component in the ferroelectric phase region changes from the outside toward the center.

For example, as shown in FIGS. 2 and 3, the dielectric ceramic composition according to the present invention has crystal grains composed of a diffusion phase region and a ferroelectric phase region. The ferroelectric phase region is composed of an outer ferroelectric phase region and an inner ferroelectric phase region. The dielectric ceramic composition of the embodiment shown in FIGS. 2 and 3 is a dielectric ceramic composition mainly composed of barium titanate (BaTiO ₃ ) and manganese oxide (MnO).

  The grain boundaries of the crystal grains are determined from, for example, the TEM photograph shown in FIG. 2, and the boundary between the diffusion phase region and the ferroelectric phase region is similarly determined from the TEM photograph. The boundary between the outer ferroelectric phase region and the inner ferroelectric phase region in the ferroelectric phase region cannot be determined from the TEM photograph shown in FIG.

  As shown in FIG. 2, six analysis points I to VI are taken from the grain boundary toward the center, and the result of measuring the concentration of MnO at each analysis point is shown in FIG. 3. As shown in FIG. 3, the ferroelectric phase region of the present embodiment has a MnO concentration change from the outside toward the center, and compared with the vicinity of the center of the region, the diffusion phase and the ferroelectric phase region. In the vicinity of the boundary, the concentration of MnO is high. Further, the ferroelectric phase region includes MnO, an outer region where the concentration distribution exists, and an inner region where the MnO is hardly included. This outer region is referred to as an outer ferroelectric phase region, and the inner region is referred to as an inner ferroelectric phase region. The boundary between the outer ferroelectric phase region and the inner ferroelectric phase region cannot be discriminated from the TEM photograph shown in FIG.

  In the composition of the present invention, the molar ratio (M / A + B) of the M component to the total barium titanate (A + B) in the composition is not particularly limited, but is preferably 0.0005 to 0.01, more preferably 0. 0.001 to 0.007.

In addition, the subcomponent that can be included in the composition according to the present invention is not particularly limited, but at least one oxide selected from the group consisting of MgO, CaO, BaO, SrO and Cr ₂ O ₃ , and In addition, a compound that becomes an oxide by firing (for example, MgCO ₃ ) can be used.

Examples of other additives include sintering aids such as SiO ₂ and Al ₂ O ₃ . This type of sintering aid has the effect of lowering the sintering temperature. In addition, the capacitance temperature characteristic is not significantly affected.

Furthermore, examples of other subcomponents include at least one oxide selected from the group consisting of V ₂ O ₅ , MoO ₃ and WO ₃ .
Still other subcomponents include oxides of rare earth elements such as Y.

  The multilayer ceramic capacitor using the dielectric ceramic composition of the present invention is suitable for use as an electronic device for equipment used in an environment of 80 ° C. or higher, particularly 85 to 125 ° C. In such a temperature range, the temperature characteristic of the capacitance is the B characteristic of EIAJ standard [capacitance change rate within ± 10% at −25 to 85 ° C. (reference temperature 20 ° C.)], the X7R characteristic of EIA standard (−55 to 55 ° C.). 125 ° C. and ΔC / C = within ± 15%) can be satisfied at the same time.

  In a multilayer ceramic capacitor, an AC electric field and a DC electric field are usually applied to the dielectric layer in a superimposed manner. However, even if such an electric field is applied, the capacitor according to the present invention has extremely high temperature characteristics of the capacitance. It is stable.

Internal electrode layer 3
The conductive material contained in the internal electrode layer 3 is not particularly limited, but a 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 may be appropriately determined according to the application, etc., but it is usually preferably about 0.5 to 5 μm, particularly preferably about 0.5 to 2.5 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 may be appropriately determined according to the application, but is usually preferably about 10 to 100 μm.

Manufacturing Method of Multilayer Ceramic Capacitor A multilayer ceramic capacitor using the dielectric ceramic composition of the present invention is a green chip produced by a normal printing method or sheet method using a paste, as in the case of a conventional multilayer ceramic capacitor. After firing, the external electrode is printed or transferred and fired. Hereinafter, the manufacturing method will be specifically described.

  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, the above-mentioned oxide, a mixture thereof, and a composite oxide can be used. In addition, various compounds that become the above-described oxide or composite oxide by firing, for example, carbonate, oxalate, It can be appropriately selected from nitrates, hydroxides, organometallic compounds, etc., and used in combination. 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.
The dielectric material is usually used as a powder having an average particle size of about 0.1 to 1 μm.

  When preparing the dielectric material, after calcining barium titanate (A) and M component, the compound obtained in the calcining step and other barium titanate (B) are mixed. Then, the dielectric material is adjusted. Although calcining temperature is not specifically limited, Preferably it is 1000-1300 degreeC, More preferably, it is 1000-1100 degreeC. If the calcining temperature is too low, the DC bias voltage characteristics tend to be poor, and if the calcining temperature is too high, pulverization after calcining becomes difficult and adjustment of the dielectric material tends to be difficult.

  The molar ratio (M / A) of the M component to the barium titanate (A) is not particularly limited, but is preferably 0.0010 to 0.0120, and more preferably 0.0020 to 0.0080. The molar ratio (B / A) of post-added barium titanate (B) to barium titanate (A) before calcination is not particularly limited, but is preferably 0.05 to 5.00, more preferably 0.10 to 1.00. By setting such a molar ratio, it is possible to easily obtain a dielectric ceramic composition having a ferroelectric phase region in which the concentration of the M component changes from the outside toward the center, and exhibits excellent characteristics. become. When M / A is too large, the dielectric constant tends to decrease.

  The organic vehicle used for the paste 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. Further, 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, depending on 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, or the like may be used.

The internal electrode layer paste is prepared by kneading the above-mentioned organic vehicle with various conductive metals made of various dielectric metals and alloys, or various oxides, organometallic compounds, resinates, etc. that become the above-mentioned conductive materials after firing. Prepare.
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 laminated and printed 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 dielectric layer paste is used to form a green sheet, the internal electrode layer paste is printed thereon, and these are stacked to form a green chip.

Before firing, the green chip is subjected to binder removal processing. The binder removal treatment may be performed under normal conditions, but when a base metal such as Ni or Ni alloy is used as the conductive material of the internal electrode layer, it is particularly preferable to perform under the following conditions.
Temperature increase rate: 5 to 300 ° C./hour, particularly 10 to 100 ° C./hour,
Holding temperature: 180-400 ° C, especially 200-300 ° C,
Temperature holding time: 0.5 to 24 hours, especially 5 to 20 hours,
Atmosphere: in the air.

The atmosphere at the time of green chip firing may be appropriately determined according to the type of 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 content in the firing atmosphere The pressure is preferably 10 ⁻⁸ to 10 ⁻¹⁵ atm. 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.

  Moreover, the holding temperature at the time of baking becomes like this. Preferably it is 1100-1400 degreeC, More preferably, it is 1200-1360 degreeC, More preferably, it is 1200-1320 degreeC. If the holding temperature is lower than the above range, the densification becomes insufficient. If the holding temperature is higher than the above range, the electrode temperature is interrupted due to abnormal sintering of the internal electrode layer, the capacity temperature characteristic deteriorates due to diffusion of the constituent material of the internal electrode layer, and the dielectric Reduction of the body porcelain composition is likely to occur.

Various conditions other than the above conditions are preferably selected from the following ranges.
Temperature increase rate: 50 to 500 ° C./hour, particularly 200 to 350 ° C./hour,
Temperature holding time: 0.5-8 hours, especially 1-3 hours,
Cooling rate: 50 to 500 ° C./hour, in particular 200 to 350 ° C./hour.
Note that the firing atmosphere is preferably a reducing atmosphere, and as the atmosphere gas, for example, a mixed gas of N ₂ and H ₂ is preferably used after being humidified.

  When firing in a reducing atmosphere, it is preferable to anneal the capacitor element body. Annealing is a process for re-oxidizing the dielectric layer, and this can significantly increase the IR lifetime, thereby improving the reliability.

The oxygen partial pressure in the annealing atmosphere is preferably 10 ⁻⁹ atm or more, particularly preferably 10 ⁻⁶ to 10 ⁻⁹ atm. When the oxygen partial pressure is less than the above range, it is difficult to reoxidize the dielectric layer, and when it exceeds the above range, the internal electrode layer tends to be oxidized.

  The holding temperature at the time of annealing is preferably 1100 ° C. or less, particularly 500 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.

Various conditions other than the above conditions are preferably selected from the following ranges.
Temperature holding time: 0 to 20 hours, especially 6 to 10 hours,
Cooling rate: 50 to 500 ° C./hour, particularly 100 to 300 ° C./hour In addition, it is preferable to use humidified N ₂ gas or the like as the atmosphere gas.

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. When these are performed continuously, after removing the binder, the atmosphere is changed without cooling, and then the temperature is raised to the holding temperature at the time of baking to perform baking, and then cooled to reach the annealing holding temperature. Sometimes it is preferable to perform annealing by changing the atmosphere. On the other hand, when performing these independently, at the time of firing, after raising the temperature under N ₂ gas atmosphere with N ₂ gas or wet to the holding temperature of the binder removal processing, further continuing the heating to change the atmosphere Preferably, after cooling to the holding temperature at the time of annealing, it is preferable to change to the N ₂ gas or humidified N ₂ gas atmosphere again and continue cooling. In annealing, the temperature may be changed to a holding temperature in an N ₂ gas atmosphere, and then the atmosphere may be changed, or the entire annealing process may be a humidified N ₂ gas atmosphere.

The capacitor element body obtained as described above is subjected to end surface polishing, for example, by barrel polishing or sand blasting, and the external electrode paste is printed or transferred and baked to form the external electrode 4. The firing condition of the external electrode paste is preferably, for example, about 10 minutes to 1 hour at 400 to 800 ° C. in a humidified mixed gas of N ₂ and H ₂ . 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 the present invention thus manufactured is mounted on a printed circuit board by soldering or the like and used for various electronic devices.

  The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.

  For example, 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 is composed of a dielectric ceramic composition having the above composition. Any material having a dielectric layer can be used.

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

Example 1
First, 0.5 mol% of MnCO ₃ was weighed with respect to 100 mol% of barium titanate (A) composed of BaTiO ₃ , and these were mixed in a zirconia ball in a pure water ball mill for 16 hours. Then, this mixture was dried by evaporating water in a high-temperature bath at 130 ° C., and the powder obtained after drying was calcined at 1100 ° C. to obtain a mixture of BaTiO ₃ and MnO. The calcining may be performed in the air or in a reducing atmosphere.

Next, 50 mol% post-added barium titanate (B), 2.5 mol% MgCO ₃ , and 2.5 mol% of 100 mol% of barium titanate (A) before calcining Y ₂ O ₃ , 1.5 mol% CaCO ₃ and 4 mol% SiO ₂ were weighed. These were mixed together with a mixture of BaTiO ₃ and MnO after calcining in a zirconia ball in a pure water ball mill for 16 hours. Thereafter, the mixture was dried by evaporating water in a high-temperature bath at 130 ° C. to obtain a dielectric material.

  The barium titanate (A) before calcining and the post-added barium titanate (B) may have the same particle diameter or different particle diameters, and their production methods are also the same. May be different. For example, these barium titanates may be any of a solid phase method, an oxalate method, a hydrothermal synthesis method, an alkoxide method, and a sol-gel method. Moreover, although these particle sizes are not specifically limited, For example, it is 0.1-1.0 micrometer.

  Next, 100% by weight of the dielectric material, 4.8% by weight of acrylic resin, 40% by weight of methylene chloride, 20% by weight of ethyl acetate, 6% by weight of mineral spirits, and 4% by weight of acetone are mixed with a ball mill to form a paste, A dielectric layer paste was obtained.

  As for the internal electrode paste, 34.6% by weight of nickel particles having an average particle diameter of 0.4 μm, 52% by weight of terpineol, 3% by weight of ethylcellulose, and 0.4% by weight of benzotriol are mixed into three rolls. And kneaded to prepare a paste.

  For the external electrode paste, 100% by weight of copper particles having an average particle size of 0.5 μm, 35% by weight of an organic vehicle (8% by weight of ethylene cellulose dissolved in 92% by weight of butyl carbitol) and 7% by weight of butyl carbitol Was kneaded with three rolls to prepare a paste.

  Next, using the dielectric layer paste described above, a green sheet having a thickness of 30 μm was formed on the PET film. After the internal electrode paste was printed thereon, the green sheet was peeled off from the PET film. The green sheets thus obtained were laminated and pressure-bonded to produce a green chip. The number of green sheets having internal electrodes was four.

  The green chip was cut into a predetermined size and subjected to binder removal processing, firing and annealing to obtain a multilayer ceramic fired body. The size of each fired body sample was 3.2 mm × 1.6 mm × 0.6 mm, the thickness of the dielectric layer was about 20 μm, and the thickness of the internal electrode layer was 2 μm.

  Next, after polishing the end face of this multilayer ceramic fired body by sandblasting, the external electrode paste is transferred to the end face, and fired at 800 ° C. for 10 minutes in a humidified nitrogen gas and hydrogen gas atmosphere to form the external electrode. Thus, a multilayer ceramic capacitor sample was obtained.

The binder removal process was performed under the following conditions.
Temperature rising rate: 15 ° C / hour,
Holding temperature: 240 ° C.
Temperature holding time: 8 hours,
Atmosphere: In air.

Firing was performed under the following conditions.
Temperature increase rate: 300 ° C / hour,
Holding temperature: 1275 ° C.
Temperature holding time: 2 hours,
Cooling rate: 300 ° C./hour,
Firing atmosphere: using a humidified mixed gas of N ₂ and H ₂ ,
Oxygen partial pressure: ^10-12 atm.

Annealing was performed under the following conditions.
Holding temperature: 1050 ° C.
Temperature holding time: 2 hours,
Cooling rate: 300 ° C./hour,
Annealing atmosphere: Use humidified N ₂ gas,
Oxygen partial pressure: 10 ⁻⁶ atm.

  The multilayer ceramic capacitor sample thus obtained was measured for relative dielectric constant (ε), dielectric loss (tan δ), and capacitance-temperature characteristics. The multilayer ceramic capacitor was measured for capacitance and dielectric loss (tan δ) under conditions of 1 kHz and 1 Vrms using an LCR meter. The relative dielectric constant (ε) was calculated from the obtained capacitance, electrode dimensions, and interelectrode distance. The results are shown in Table 1.

  Regarding the temperature characteristics of the capacitance, the capacitance of the multilayer ceramic capacitor sample was measured using a LCR meter at a voltage of 1 V in the temperature range of −55 ° C. to 125 ° C. and the reference temperature was 25 ° C. If the rate of change is within ± 15% within the range of -55 ° C to 125 ° C (electronic machinery industry EIA standard X7R), the X7R temperature characteristics shall be considered. It was set as “x”. The results are shown in FIG. As shown in FIG. 4A and Table 1, in Example 1, it was confirmed that the X7R characteristics were satisfied.

  Further, the insulation resistance (IR) at 25 ° C. was measured for the capacitor sample. The voltage at the time of measuring the insulation resistance (IR) was DC 100 V, and the value was 60 seconds after the start of application (unit: “Ω”). The results are shown in Table 1.

  Moreover, the voltage characteristic was measured about the capacitor | condenser sample. In Table 1, a DC bias voltage of 2 V / μm was applied to the capacitor sample, and the capacitance change rate (ΔC / C:%) was shown as voltage characteristics. FIG. 5A shows a graph of the rate of change in capacity (ΔC / C:%) with respect to the DC bias voltage in the sample of Example 1. FIG. According to Example 1, it was confirmed that the capacity change rate was small even under a high DC voltage.

  Moreover, the result of having image | photographed using the transmission electron microscope (TEM; the product number JEM-2000FXII by JEOL Co., Ltd.) about the dielectric material layer of a capacitor | condenser sample is shown in FIG. 2, 6 analysis points I to VI are taken from the grain boundary toward the center, and the result of measuring the concentration of MnO using EDS (product number TN5402 manufactured by Nolan Instrument Co., Ltd.) is shown in FIG. Shown in As shown in FIG. 3, the ferroelectric phase region of Example 1 has a change in MnO concentration from the outside toward the center, and the MnO concentration is higher on the outside than near the center of the region. It was confirmed that Further, it was confirmed that the ferroelectric phase region has an outer region where the concentration distribution of MnO exists and an inner region which hardly contains MnO.

  In the determination results in Table 1, ◎ indicates that the X7R characteristics are satisfied and other characteristics (ε, voltage characteristics, tan δ, IR) are excellent, and one of the other characteristics is inferior. However, a sample satisfying the X7R characteristic was indicated as ◯, and a sample not satisfying the X7R characteristic was indicated as ×.

Examples 2-4
As shown in Table 1, a capacitor sample was prepared in the same manner as in Example 1 except that FeO, CoO, or NiO was used instead of MnO, and the same test as in Example 1 was performed. As shown in Table 1, it was confirmed that the dielectric constant (ε), temperature characteristics, voltage characteristics, dielectric loss (tan δ), and insulation resistance (IR) had excellent characteristics equivalent to those of Example 1.

Examples 5-8
As shown in Table 1, the molar ratio (M / A) of MnO to barium titanate (A) before calcination was 0.1 mol%, 0.2 mol%, 1.2 mol% and 5 mol%. A capacitor sample was produced in the same manner as in Example 1 except that it was changed, and the same test as in Example 1 was performed. As shown in Table 1, it was confirmed that the dielectric constant (ε), temperature characteristics, voltage characteristics, dielectric loss (tan δ), and insulation resistance (IR) had excellent characteristics equivalent to those of Example 1. However, it was confirmed that Example 5 was inferior to other examples in terms of voltage characteristics because the ratio of MnO was too small. Further, in Example 8, it was confirmed that the dielectric constant was low because M / A was too large.

Comparative Examples 1-5
As shown in Table 1, the molar ratio (M / A) of MnO to barium titanate (A) before calcination is changed, and after calcination, post-added barium titanate (B) is additionally added. However, a capacitor sample was prepared in the same manner as in Example 1 except that the dielectric material was adjusted, and the same test as in Example 1 was performed. Only Comparative Example 5 was different from other Comparative Examples 1 to 4 in that post-added barium titanate (B) was additionally added, but the molar amount (B / A) of the addition amount was as low as 1%.

  As shown in Table 1, in Comparative Examples 1 to 5, it was confirmed that the dielectric constant (ε) was low and the X7R characteristics were not satisfied (temperature characteristics were deteriorated) as compared with the Examples. A temperature characteristic graph of the sample according to Comparative Example 4 is shown in FIG.

  Moreover, about the dielectric material layer of the capacitor | condenser sample which concerns on Comparative Examples 1-5, 6 analysis points I-VI are taken from the grain boundary of a crystal grain toward the center similarly to Example 1, and the density | concentration of MnO is taken. As a result of the measurement, in the ferroelectric phase region, almost no change in the concentration of MnO was observed from the outside toward the center, and it was confirmed that it was substantially uniform.

Examples 9-17
As shown in Table 1, a capacitor was obtained in the same manner as in Example 1 except that the molar ratio (B / A) of post-added barium titanate (B) to barium titanate (A) before calcination was changed. A sample was prepared and the same test as in Example 1 was performed.

  As shown in Table 1, it was confirmed that the dielectric constant (ε), temperature characteristics, voltage characteristics, dielectric loss (tan δ), and insulation resistance (IR) had excellent characteristics equivalent to those of Example 1. However, it was confirmed that Example 17 was inferior to the other Examples in terms of voltage characteristics because the molar ratio B / A was too large.

Examples 18-24
As shown in Table 1, a capacitor sample was prepared in the same manner as in Example 1 except that the calcining temperature was changed, and the same test as in Example 1 was performed.

  As shown in Table 1, it was confirmed that the dielectric constant (ε), temperature characteristics, voltage characteristics, dielectric loss (tan δ), and insulation resistance (IR) had excellent characteristics equivalent to those of Example 1. However, it was confirmed that Example 18 was inferior to the other examples in terms of voltage characteristics because the calcining temperature was too low. The voltage characteristics of the sample in Example 18 are shown in FIG. Moreover, regarding Example 24, pulverization after calcination was difficult.

  As described above, according to the present invention, both the X7R characteristic (EIA standard) and the B characteristic (EIAJ standard) indicating the temperature characteristic of the electrostatic capacity can be satisfied, and the electrostatic capacity and the insulation can be achieved. Resistant voltage dependence, excellent dielectric breakdown resistance, and suitable for use as an electronic component such as a multilayer capacitor in which Ni or Ni alloy can be used as an internal electrode layer, and as a dielectric layer of the electronic component Products and methods of manufacturing the same can be provided.

DESCRIPTION OF SYMBOLS 1 ... Multilayer ceramic capacitor 2 ... Dielectric layer 3 ... Internal electrode layer 4 ... External electrode 10 ... Capacitor element main body

Claims (6)

Ferroelectric phase mainly composed of barium titanate and M component (where M is at least one component selected from the group consisting of manganese oxide, iron oxide, cobalt oxide and nickel oxide) A dielectric ceramic composition having a region,
A dielectric ceramic composition, wherein a concentration of the M component in the ferroelectric phase region is higher on the outer side than in the vicinity of the center of the ferroelectric phase region .   The ferroelectric phase region is composed of an outer ferroelectric phase region and an inner ferroelectric phase region, and the M component of the outer ferroelectric phase region is compared with the inner ferroelectric phase region. The dielectric ceramic composition according to claim 1, wherein the concentration is high. The dielectric ceramic composition according to claim 2 , wherein the inner ferroelectric phase region does not substantially contain the M component. The dielectric ceramic composition according to any one of claims 1 to 3 , wherein a diffusion phase region exists outside the ferroelectric phase region. An electronic component having a dielectric layer,
The dielectric layer is mainly composed of barium titanate and an M component (where M is at least one component selected from the group consisting of manganese oxide, iron oxide, cobalt oxide and nickel oxide). And having a dielectric ceramic composition having a ferroelectric phase region,
The electronic component according to claim 1, wherein the concentration of the M component in the ferroelectric phase region is higher on the outside than in the vicinity of the center of the ferroelectric phase region . The electronic component according to claim 5 , further comprising an internal electrode layer containing nickel or a nickel alloy.

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