JP5034839B2 - Dielectric porcelain composition and electronic component - Google Patents

Abstract

A dielectric ceramic composition comprising BamTiO2+m (note that "m" satisfies 0. 99 ≤ m ≤ 1.01) and BanZrO2+n (note that "n" satisfies 0. 99 ≤ n ≤ 1.01), an oxide of Mg, an oxide of R (note that 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), an oxide of at least one element selected from Mn, Cr, Co and Fe, and an oxide of at least one element selected from Si, Li, Al, Ge and B. With respect to 100 moles of said BamTiO2+m, 35 to 65 moles of BanZro2+n, 4 to 12 moles of an oxide of Mg, 4 to 15 moles of an oxide of R, 0. 5 to 3 moles of an oxide of Mn, Cr, Co and Fe, and 3 to 9 moles of an oxide of Si, Li, Al Ge and B are included therein.

Description

  The present invention relates to a dielectric ceramic composition having resistance to reduction and an electronic component having the dielectric ceramic composition in a dielectric layer. More specifically, the present invention is suitable for medium to high voltage applications having a high rated voltage (for example, 100 V or more). The present invention relates to a dielectric ceramic composition and an electronic component that are suitably used.

  A multilayer ceramic capacitor, which is an example of an electronic component, includes, for example, a ceramic green sheet made of a predetermined dielectric ceramic composition and an internal electrode layer having a predetermined pattern alternately stacked, and then integrated into a green chip obtained simultaneously. Manufactured by firing. Since the internal electrode layer of the multilayer ceramic capacitor is integrated with the ceramic dielectric by firing, it is necessary to select a material that does not react with the ceramic dielectric. For this reason, as a material constituting the internal electrode layer, conventionally, an expensive noble metal such as platinum or palladium has been inevitably used.

  However, in recent years, dielectric ceramic compositions that can use inexpensive base metals such as nickel and copper have been developed, and a significant cost reduction has been realized.

  On the other hand, there is a high demand for miniaturization of electronic components accompanying the increase in density of electronic circuits, and miniaturization and large capacity of multilayer ceramic capacitors are rapidly progressing. Accordingly, the dielectric layer per layer in the multilayer ceramic capacitor has been thinned, and a dielectric ceramic composition that can maintain the reliability as a capacitor even when the layer is thinned is demanded. In particular, in order to reduce the size and increase the capacity of a medium- and high-voltage capacitor used at a high rated voltage (for example, 100 V or higher), very high reliability is required for the dielectric ceramic composition constituting the dielectric layer. The

On the other hand, for example, in Patent Document 1, as a dielectric ceramic composition for a capacitor used under high frequency and high voltage alternating current, a composition formula: ABO ₃ + aR + bM (where ABO ₃ is a barium titanate solid solution) , R is an oxide of a metal element such as La, and M is an oxide of a metal element such as Mn). A dielectric ceramic composition containing a material is disclosed. In Patent Document 1, XZrO ₃ (where X is at least one metal element selected from Ba, Sr, and Ca) is added as an additive component in the main component, and titanium represented by ABO ₃ in the main component. The point which adds in 0.35 mol or less with respect to 1 mol of barium acid solid solutions is described.

However, this Patent Document 1 has a problem that the withstand voltage (breakdown voltage) is low and the life characteristics (accelerated life of the insulation resistance) are insufficient, and therefore the reliability is poor. In particular, this problem becomes more prominent when the multilayer ceramic capacitor is downsized and increased in capacity. Therefore, in order to achieve downsizing and increased capacity, improvement in breakdown voltage and life characteristics (accelerated life of insulation resistance) is desired. It was rare.
Japanese Patent No. 3567759

  The present invention has been made in view of such a situation, and can be fired in a reducing atmosphere, has a low electrostriction amount when a voltage is applied, and maintains a good dielectric constant and capacitance-temperature characteristics while maintaining a withstand voltage ( It is an object of the present invention to provide a dielectric ceramic composition capable of improving the breakdown voltage) and the accelerated lifetime of insulation resistance, and an electronic component having this dielectric ceramic composition as a dielectric layer.

In order to achieve the above object, a dielectric ceramic composition according to the first aspect of the present invention comprises:
Ba _m TiO _{2 + m} (where m is 0.99 ≦ m ≦ 1.01),
Ba _n ZrO _{2 + n} (where n is 0.99 ≦ n ≦ 1.01),
Mg oxide,
R oxide (where 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) )When,
An oxide of at least one element selected from Mn, Cr, Co and Fe;
A dielectric ceramic composition comprising an oxide of at least one element selected from Si, Li, Al, Ge and B,
The ratio of each component in terms of oxide or composite oxide with respect to 100 moles of Ba _m TiO _{2 + m} ,
Ba _n ZrO _{2 + n} : 35 to 65 mol,
Mg oxide: 4 to 12 mol,
R oxide: 4 to 15 mol,
Mn, Cr, Co and Fe oxides: 0.5-3 mol,
Si, Li, Al, Ge and B oxides: 3-9 mol,
It is.

In the present invention, preferably, relative to the _Ba m _{TiO 2} + m 100 moles, the ratio of the _{Ba n ZrO 2 +} n _is in Ba _{n ZrO 2 +} n in terms of a 40 to 55 mol.

The dielectric ceramic composition according to the second aspect of the present invention is:
A dielectric ceramic composition having a first component represented by the general formula of (Ba _a R _b ) _α (Ti _c Zr _d Mg _e ) O ₃ ,
R in the above general formula is a rare earth element,
In the above general formula:
0.8 ≦ a ≦ 0.96,
0.04 ≦ b ≦ 0.2,
0.55 ≦ c ≦ 0.7,
0.24 ≦ d ≦ 0.39,
0.02 ≦ e ≦ 0.09, and 1 ≦ α ≦ 1.15,
Ba _m TiO _{2 + m} contained in the first component (where m is 0.99 ≦ m ≦ 1.01) per 100 moles,
0.5 to 3.0 mol of an oxide of at least one element selected from Mn, Cr, Co and Fe;
And 3 to 9 mol of an oxide of at least one element selected from Si, Li, Al, Ge and B.

  According to the present invention, there is provided an electronic component having a dielectric layer and an internal electrode layer, wherein the dielectric layer is composed of the dielectric ceramic composition according to the first aspect or the second aspect. Parts are provided.

  The electronic component according to the present invention is not particularly limited, and examples thereof include a multilayer ceramic capacitor, a piezoelectric element, a chip inductor, a chip varistor, a chip thermistor, a chip resistor, and other surface mount (SMD) chip type electronic components.

Since the dielectric ceramic composition of the present invention has the specific composition described above, it can be fired in a reducing atmosphere, has a low electrostriction amount when a voltage is applied, and has a relative dielectric constant and capacitance-temperature characteristics. It is possible to improve the withstand voltage and the accelerated life of the insulation resistance while maintaining good. In particular, in the present invention, the capacity temperature characteristic and the pressure resistance are improved by relatively increasing the ratio of Ba _n ZrO _{2 + n} to 35 to 65 mol, preferably 40 to 55 mol, relative to 100 mol of Ba _m TiO _{2 + m.} An improved dielectric ceramic composition can be provided.

  Therefore, by applying such a dielectric ceramic composition of the present invention to a dielectric layer of an electronic component such as a multilayer ceramic capacitor, for example, the dielectric layer is thinned to about 20 μm and has a high rated voltage ( For example, high reliability can be achieved even when used for medium-high pressure applications (for example, 100 V or higher, particularly 250 V or higher). That is, it is possible to provide an electronic component for medium- and high-pressure applications that is small and has a large capacity and has high reliability.

  Such an electronic component of the present invention can be suitably used, for example, for various automobile-related applications (fuel injection devices, HID lamps, etc.) and digital still camera applications.

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

FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention.

(First embodiment)
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. 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. 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.

  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 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:
Ba _m TiO _{2 + m} (where m is 0.99 ≦ m ≦ 1.01),
Ba _n ZrO _{2 + n} (where n is 0.99 ≦ n ≦ 1.01),
Mg oxide,
R oxide (where 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) )When,
An oxide of at least one element selected from Mn, Cr, Co and Fe;
And an oxide of at least one element selected from Si, Li, Al, Ge, and B.

In the Ba _m TiO _{2 + m} , m is 0.99 ≦ m ≦ 1.01. At this time, the amount of oxygen (O) may be slightly deviated from the stoichiometric composition of the above formula. Ba _m TiO _{2 + m} is mainly contained in the dielectric ceramic composition as a base material.

The content of Ba _n ZrO _{2 + n,} to the Ba _{m TiO 2} + _m 100 _moles, in Ba _{n ZrO 2 +} n in terms of a 35 to 65 mol, preferably 40 to 55 mol, more preferably 40 to 50 mol is there. Moreover, _n in Ba _n ZrO _{2 +} n is 0.99 ≦ n ≦ 1.01. At this time, the amount of oxygen (O) may be slightly deviated from the stoichiometric composition of the above formula. By adding Ba _n ZrO _{2 + n} in the above range, the capacity-temperature characteristics and the breakdown voltage can be improved. _If the amount of Ba _n ZrO _{2 + n} added is too small, the lifetime characteristics tend to deteriorate in addition to the decrease in capacity-temperature characteristics and breakdown voltage. On the other hand, if the amount is too large, the relative permittivity tends to decrease.

The content of the oxide of _Mg, relative to Ba _{m TiO 2} + _m 100 mol, in terms of MgO, and 4 to 12 moles, preferably from 6 to 10 moles, more preferably from 7 to 9 moles. Mg oxide has the effect of suppressing the ferroelectricity of Ba _m TiO _{2 + m} . If the content of the Mg oxide is too small, the capacitance-temperature characteristics and the breakdown voltage tend to decrease, and the amount of electrostriction during voltage application tends to increase. On the other hand, if the amount is too large, the dielectric constant tends to decrease, and the life characteristics and the breakdown voltage tend to deteriorate.

Content of the oxide of _R, to the Ba _{m TiO 2} + _m 100 _moles, with R 2 _{O 3} in terms of a 4 to 15 moles, preferably from 6 to 12 moles, more preferably at 7 to 11 moles is there. R oxide mainly _has an effect to suppress the strong dielectric property of Ba m _{TiO 2 + m.} If the content of the R oxide is too small, the withstand voltage tends to decrease or the amount of electrostriction during voltage application tends to increase. On the other hand, if the amount is too large, the relative permittivity tends to decrease. The R element constituting the R oxide is selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Among these, Gd is particularly preferable.

The content of oxides of Mn, Cr, Co and Fe is 0.5 to 3 mol in terms of MnO, Cr ₂ O ₃ , Co ₃ O ₄ or Fe ₂ O _{3 with} respect to 100 _m of Ba _m TiO _{2 + m.} Preferably, it is 0.5-2.5 mol, More preferably, it is 1.0-2.0 mol. If the content of these oxides is too small, the life characteristics tend to deteriorate. On the other hand, when the amount is too large, the relative dielectric constant decreases and the capacity-temperature characteristic tends to deteriorate.

The content of oxides of Si, Li, Al, Ge, and B is equivalent to SiO ₂ , Li ₂ O ₃ , Al ₂ O ₃ , Ge ₂ O ₂ or B ₂ O _{3 with} respect to 100 moles of Ba _m TiO _{2 + m.} And 3 to 9 mol, preferably 4 to 8 mol, and more preferably 4 to 6 mol. If the content of these oxides is too small, the relative dielectric constant decreases and the life characteristics tend to deteriorate. On the other hand, if the amount is too large, the capacity-temperature characteristic tends to deteriorate. Of the above oxides, it is preferable to use an oxide of Si because the effect of improving the characteristics is great.

In the present embodiment, the dielectric ceramic composition can be fired in a reducing atmosphere by containing the above-mentioned components in the predetermined amounts, and the amount of electrostriction when voltage is applied is low. In addition, the accelerated lifetime of the dielectric constant, withstand voltage, and insulation resistance can be improved. In particular, problems due to Ba _m TiO _{2 + m} contained mainly as a base material, such as capacity dependency with respect to an applied voltage, and electrostriction at the time of voltage application can be effectively alleviated. In addition, in this embodiment, since the content of Ba _n ZrO _{2 + n} is relatively large, it is possible to improve the capacity-temperature characteristics and the breakdown voltage while maintaining the above-mentioned characteristics in good condition.

  In this specification, each oxide or composite oxide constituting each component is represented by a stoichiometric composition, but the oxidation state of each oxide or composite oxide is out of the stoichiometric composition. There may be. However, the said ratio of each component is calculated | required by converting into the oxide or composite oxide of the said stoichiometric composition from the metal amount contained in the oxide or composite oxide which comprises each component.

  The thickness of the dielectric layer 2 is not particularly limited, and may be appropriately determined according to the use of the multilayer ceramic capacitor 1.

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 internal electrode layer 3 may be formed using a commercially available electrode paste. What is necessary is just to determine the thickness of the internal electrode layer 3 suitably according to a use etc.

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. What is necessary is just to determine the thickness of the external electrode 4 suitably according to a use etc.

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 (dielectric ceramic composition 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, 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 An acid salt, a nitrate, a hydroxide, an organometallic compound, or the like can be appropriately selected and mixed for use. 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.

In addition, among the raw materials of the above components, at least a part of the raw materials other than Ba _m TiO _{2 + m} , the respective oxides or composite oxides, and the compounds that become the respective oxides or composite oxides by firing are used as they are. Alternatively, it may be calcined in advance and used as roasted powder. Alternatively, some of the raw materials other than Ba _n ZrO _{2 + n} may be calcined together with Ba _m TiO _{2 + m} . However, if Ba _m TiO _{2 + m} and Ba _n ZrO _{2 + n} are calcined, it is difficult to obtain the effects of the present invention.

_As the raw material of Ba m _{TiO 2 + m,} the average particle diameter is preferably is preferably of a 0.2 to 1 [mu] m. Moreover, as a raw material of other components including Ba _n ZrO _{2 + n} , it is preferable to use those having an average particle diameter of preferably 0.2 to 1 μm. In addition, when these are calcined in advance and used as roasted powder, the average particle diameter is preferably within the above range.

  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 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 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. 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 firing atmosphere is air or a reducing atmosphere.

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 ⁻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.

  Moreover, the holding temperature at the time of baking becomes like this. Preferably it is 1000-1400 degreeC, More preferably, it is 1100-1360 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 is interrupted due to abnormal sintering of the internal electrode layer, the capacity-temperature characteristic is deteriorated due to diffusion of the internal electrode layer constituent material, Reduction of the body porcelain composition is likely to occur.

As other firing conditions, the rate of temperature rise is preferably 50 to 500 ° C./hour, more preferably 200 to 300 ° C./hour, and the temperature holding time is preferably 0.5 to 8 hours, more preferably 1 to 3 hours. The time and cooling rate are preferably 50 to 500 ° C./hour, more preferably 200 to 300 ° C./hour. Further, the firing atmosphere is preferably a reducing atmosphere, and as the atmosphere gas, for example, a mixed gas of N ₂ and H ₂ can be used by humidification.

  After firing in a reducing atmosphere, the capacitor element body is preferably annealed. 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 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, 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 high temperature load life is likely to be shortened. On the other hand, when 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, and the high temperature is increased. The load 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 10 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. Further, 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.

(Second Embodiment)
The multilayer ceramic capacitor and the manufacturing method thereof according to the second embodiment of the present invention are the same as the composition of the dielectric ceramic composition and the manufacturing method thereof, and the composition of the dielectric ceramic composition and the manufacturing method thereof according to the first embodiment; Except for the differences as described below, they are the same, and the description of the overlapping parts is omitted.

The dielectric ceramic composition according to the second embodiment is
A first component represented by the general formula of (Ba _a R _b ) _α (Ti _c Zr _d Mg _e ) O ₃ ;
A second component comprising an oxide of at least one element selected from Mn, Cr, Co and Fe;
And a third component made of an oxide of at least one element selected from Si, Li, Al, Ge, and B. R in the above general formula is the same rare earth element as in the first embodiment, preferably Gd.

In the above general formula:
0.8 ≦ a ≦ 0.96, preferably 0.83 ≦ a ≦ 0.93, more preferably 0.86 ≦ a ≦ 0.91
0.04 ≦ b ≦ 0.2, preferably 0.08 ≦ b ≦ 0.15, more preferably 0.09 ≦ b ≦ 0.13,
0.55 ≦ c ≦ 0.7, preferably 0.62 ≦ c ≦ 0.69, more preferably 0.64 ≦ c ≦ 0.68,
0.24 ≦ d ≦ 0.39, preferably 0.26 ≦ d ≦ 0.36, more preferably 0.27 ≦ d ≦ 0.31,
0.02 ≦ e ≦ 0.09, preferably 0.03 ≦ e ≦ 0.08, more preferably 0.04 ≦ e ≦ 0.07, and 1 ≦ α ≦ 1.15, preferably 1.02 ≦ α ≦ 1.12, more preferably 1.03 ≦ α ≦ 1.10.

This dielectric ceramic composition has a Ba _m TiO _{2 + m} contained in the first component (where m is 0.99 ≦ m ≦ 1.01) 100 mol,
The second component is 0.5 to 3.0 mol in terms of oxide,
The third component has 3 to 9 mol in terms of oxide.

In the dielectric ceramic composition according to the present embodiment, in the state after firing, Ba _m TiO _{2 + m} contained in the first component is sufficiently dissolved in the perovskite crystal structure, and the A site contains Rare earth R enters, and Zr and Mg enter the B site.

  In the above general formula, if a is too small, the relative permittivity tends to decrease, and if a is too large, the temperature characteristics, the high temperature accelerated life, the breakdown voltage, and the amount of electrostriction tend to deteriorate. If b is too large, the relative permittivity tends to decrease, and if b is too small, the temperature characteristics, the high temperature accelerated life, the breakdown voltage, and the amount of electrostriction tend to deteriorate.

  In the above general formula, if c is too large, the relative permittivity tends to decrease, and if c is too small, the temperature characteristics, the high temperature accelerated life, the breakdown voltage, and the amount of electrostriction tend to deteriorate. If d is too large, the relative permittivity tends to decrease, and if d is too small, the temperature characteristics, the high temperature accelerated life, and the amount of electrostriction tend to deteriorate.

  In the above general formula, if e is too large, the temperature characteristics tend to deteriorate, and if e is too small, the high temperature accelerated life tends to deteriorate. Furthermore, if α is too small, temperature characteristics tend to deteriorate, and if α is too large, reliability tends to deteriorate.

  In this embodiment, if the amount of the second component added is too small, the temperature characteristics, the high temperature accelerated life, the breakdown voltage, and the amount of electrostriction tend to deteriorate. If the amount is too large, the relative dielectric constant tends to decrease. is there. Moreover, when there is too little addition use of a 3rd component, there exists a tendency for a high temperature accelerated lifetime, a breakdown voltage, and the amount of electrostriction to deteriorate, and when too much, there exists a tendency for a dielectric constant to fall.

In order to manufacture the dielectric ceramic composition of the present embodiment, a method similar to the method of manufacturing the dielectric ceramic composition according to the first embodiment described above can be employed. Among them, for at least a part of the raw materials other than Ba _m TiO _{2 + m} , each oxide or composite oxide and a compound that becomes each oxide or composite oxide by firing are calcined in advance and used as roasted powder. Is preferred.

  Other configurations and operational effects of the present embodiment are the same as those of the first embodiment.

  As mentioned above, although embodiment of this invention was 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.

  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 has a dielectric layer having the above configuration. Anything is fine.

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

Example 1
First, Ba _m TiO _{2 + m} , Ba _n ZrO _{2 + n} , MgCO ₃ , Gd ₂ O ₃ , MnO, and SiO ₂ having an average particle diameter of 0.5 μm were prepared, and these were mixed in a ball mill, and the resulting mixed powder was obtained. Preliminarily calcined at 1200 ° C. to prepare calcined powder having an average particle diameter of 0.6 μm. Next, the obtained calcined powder was wet pulverized with a ball mill for 15 hours and dried to obtain a dielectric material. Incidentally, MgCO _3, after firing, and thus included in the dielectric ceramic composition as MgO. _Moreover, Ba _{m TiO 2 +} m inside the _{Ba n ZrO 2 + n, MgCO} 3, Gd 2 O 3, MnO, and SiO ₂ is or a solid _solution, MgCO ₃ in Ba _{m TiO 2 +} m surface, _Gd 2 _O 3, MnO, and SiO There are no restrictions on the state of the powder, such as when ₂ diffuses or MgCO ₃ particles, Gd ₂ O ₃ particles, MnO particles, and SiO ₂ particles adhere to the surface of Ba _m TiO _{2 + m} . The powder obtained by this production method is designated as powder A.

Table 1 shows the amount of each component added. In this example, as shown in Table 1, dielectric materials (sample numbers 1 to 35) having different addition amounts were prepared. In Table 1, the addition amount of each component is the addition amount in terms of composite oxide or each oxide with respect to 100 mol of Ba _m TiO _{2 + m} . In this example, Ba _m TiO _{2 + m} with m = 1.001 was used, and Ba _n ZrO _{2 + n} with n = 1.000 was used.

Next, the obtained dielectric material: 100 parts by weight, polyvinyl butyral resin: 10 parts by weight, di-Ok Chirufutareto as a plasticizer (DOP): 5 parts by weight, and alcohol as a solvent: and 100 parts by weight The paste was mixed by a ball mill 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 30 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.

Firing conditions are: temperature rising rate: 200 ° C./hour, holding temperature: 1220 to 1380 ° C., temperature holding time: 2 hours, cooling rate: 200 ° C./hour, atmospheric gas: humidified N ₂ + H ₂ mixed gas (oxygen content) Pressure: 10 ⁻¹² MPa).

The annealing conditions were as follows: temperature rising rate: 200 ° C./hour, holding temperature: 1000-1100 ° C., temperature holding time: 2 hours, cooling 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 sand blasting, In-Ga was applied as an external electrode to obtain a sample of the multilayer ceramic capacitor shown in FIG. In this example, as shown in Table 1, a plurality of capacitor samples (sample numbers 1 to 35) each having a dielectric layer composed of a plurality of dielectric ceramic compositions having different compositions were prepared. The size of the obtained capacitor sample is 3.2 mm × 1.6 mm × 3.2 mm, the thickness of the dielectric layer is 20 μm, the thickness of the internal electrode layer is 1.5 μm, and the dielectric layer sandwiched between the internal electrode layers is The number was 10.

  About each obtained capacitor | condenser sample, the dielectric constant ((epsilon) s), the capacitance temperature characteristic (TC), the high temperature accelerated lifetime (HALT), the breakdown voltage (breakdown voltage), and the amount of electrostriction by voltage application were measured by the method shown below. .

Dielectric constant εs
A capacitor with a frequency of 1 kHz and an input signal level (measurement voltage) of 1 Vrms was input with a digital LCR meter (YHP 4284A) at a reference temperature of 25 ° C., and the capacitance C was measured. The relative dielectric constant εs (no unit) was calculated based on the thickness of the dielectric layer, the effective electrode area, and the capacitance C obtained as a result of the measurement. A higher relative dielectric constant is preferable. In this example, 230 or more, preferably 250 or more was considered good. The results are shown in Table 1.

Capacity temperature characteristics (TC)
The capacitance of the capacitor sample was measured at 125 ° C. with a digital LCR meter (YHP 4284A) under the conditions of a frequency of 1 kHz and an input signal level (measurement voltage) of 1 Vrms. The rate of change with respect to was calculated. In the present example, a value within ± 15% was considered good. The results are shown in Table 1.

High temperature accelerated life (HALT)
A high temperature accelerated lifetime (HALT) was evaluated by maintaining a DC voltage applied to a capacitor sample at 200 ° C. under an electric field of 40 V / μm and measuring the lifetime. 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. Further, this high temperature accelerated life was performed for 10 capacitor samples. In this example, 10 hours or longer, preferably 20 hours or longer was considered good. The results are shown in Table 1.

Breakdown voltage (withstand voltage)
To capacitor samples at a temperature 25 ° C., a DC voltage boost rate 100 V / sec. The voltage value (unit: V / μm) relative to the thickness of the dielectric layer when a current of 10 mA flows was used as the breakdown voltage, and the breakdown voltage was measured to evaluate the withstand voltage of the capacitor sample. In this example, a breakdown voltage of 50 V / μm or more was considered good. The results are shown in Table 1.

Electrostriction due to voltage application First, the capacitor sample was fixed by soldering to a glass epoxy substrate on which electrodes of a predetermined pattern were printed. Next, a voltage was applied to the capacitor sample fixed on the substrate under the conditions of AC: 10 Vrms / μm and a frequency of 3 kHz, and the vibration width of the capacitor sample surface at the time of voltage application was measured. A laser Doppler vibrometer was used to measure the vibration width of the capacitor sample surface. In this example, the average value of values measured using 10 capacitor samples was used as the amount of electrostriction. The electrostriction amount is preferably as low as possible. In this example, less than 10 ppm was considered good. The results are shown in Table 1.

  From Table 1, by setting the dielectric ceramic composition composition within the predetermined range of the present invention, the dielectric constant (εs), the capacity-temperature characteristic (TC), and the amount of electrostriction are kept good, while the breakdown voltage (withstand voltage) ) And high temperature accelerated life (HALT) can be confirmed.

  On the other hand, when the dielectric ceramic composition was out of the scope of the present invention, the results were inferior to each characteristic.

Example 2
Ba _m instead of TiO _{2 + m} and _Ba n _{ZrO 2 + n,} except that mixed Ba _{m TiO 2 +} m and _{Ba n ZrO 2 +} n and calcinated the Ba (Ti, Zr) using _{O 3,} the additive component without calcination Produced a capacitor sample in the same manner as Sample No. 9 in Example 1, and evaluated it in the same manner as in Example 1. In this example, the addition amount of Ba (Ti, Zr) O _{3 in} the dielectric ceramic composition is the addition amount of Ba _m TiO _{2 + m} and Ba _n ZrO _{2 + n} in sample number 9 of Example 1. The same amount as the total. Further, as Ba (Ti, Zr) O ₃ , a Ti / Zr ratio having the same ratio as the ratio of Ba _m TiO _{2 + m} and Ba _n ZrO _{2 + n} in sample number 9 of Example 1 was used (ie, Ti / Zr = about 100/41 was used). The results are shown in Table 2.

From Table 2, when Ba (Ti, Zr) O ₃ is used instead of Ba _m TiO _{2 + m} and Ba _n ZrO _{2 + n} , the results are inferior in capacity-temperature characteristics, electrostriction due to voltage application, and reliability. I can confirm that. The reason for this is not necessarily clear, but in the dielectric ceramic composition of the present invention, Gd is added to Ba _m TiO _{2 + m} particles by adding Ba _m TiO _{2 + m} and Ba _n ZrO _{2 + n} separately. It becomes easy to diffuse and has a structure in which Gd is uniformly distributed in the particles. This improves the reliability by suppressing the generation of oxygen defects during firing in a reducing atmosphere, whereas such a configuration is obtained when Ba (Ti, Zr) O ₃ is used. It is thought that it is because it does not become.

Example 3
A powder sample similar to that in Example 1 was used, and a capacitor sample was prepared in the same manner as in Example 1 except for the following, and evaluated in the same manner as in Example 1.

  In Tables 3 and 4, unlike Table 1, the composition of the dielectric ceramic composition after firing is expressed as follows.

That is, the dielectric ceramic composition according to this example is
A first component represented by the general formula of (Ba _a R _b ) _α (Ti _c Zr _d Mg _e ) O ₃ ;
A second component comprising an oxide of at least one element selected from Mn, Cr, Co and Fe;
And a third component made of an oxide of at least one element selected from Si, Li, Al, Ge and B.

In Table 3 and Table 4, the molar ratio of the second component (Mn) and the third component (Si) is a molar ratio in terms of oxide to 100 mol of Ba _m TiO _{2 + m} contained in the first component. .

  From the results shown in Tables 3 and 4, by setting the dielectric ceramic composition within the predetermined range of the present invention, the relative dielectric constant (εs), the capacity-temperature characteristic (TC), and the amount of electrostriction can be kept good. However, it can be confirmed that the breakdown voltage (breakdown voltage) and the high temperature accelerated life (HALT) can be improved.

  On the other hand, when the dielectric ceramic composition was out of the scope of the present invention, the results were inferior to each characteristic.

Example 4
First, Ba _m TiO _{2 + m} (where m = 1.001), Ba _n ZrO _{2 + n} (where n = 1.000), MgCO ₃ , Gd ₂ O ₃ , MnO, and SiO _{2 having} an average particle diameter of 0.5 μm. Are prepared and mixed with a ball mill to obtain a mixed powder. The powder obtained by this production method is designated as powder B.

  A capacitor sample was prepared in the same manner as in Example 3 except that powder B was used instead of powder A, and evaluation was performed in the same manner as in Example 3. Table 5 shows the amount of each component added to the powder B and the evaluation results.

  Compared to Table 3 and Table 4, from the results shown in Table 5, the same results as in the case of using the powder A were obtained when the powder B was used, but the same compositions were compared. In this case, it was confirmed that the powder A was superior in terms of high temperature accelerated life and breakdown voltage.

Example 5
BaCO ₃ , ZrO ₂ , MgCO ₃ , Gd ₂ O ₃ , MnO, SiO ₂ and TiO ₂ were prepared, wet-ground in a ball mill for 15 hours, and dried to obtain a dielectric material. The powder obtained by this production method is designated as powder C.

  A capacitor sample was prepared in the same manner as in Example 3 except that powder C was used instead of powder A, and evaluation was performed in the same manner as in Example 3. Table 5 shows the amount of each component added and the evaluation results. As shown in Table 5, when the powder C was used, the same results as when the powder A was used were obtained.

Example 6
MgCO ₃ , Gd ₂ O ₃ , MnO, and SiO ₂ preliminarily calcined at 1000 ° C. were prepared, and this was mixed with BaCO ₃ , ZrO ₂ , and TiO ₂ powders having an average particle diameter of 0.3 μm in a ball mill at 15 Dielectric material was obtained by wet-grinding for a time and drying. The powder obtained by this production method is designated as powder D.

A capacitor sample was prepared in the same manner as in Example 3 except that powder D was used instead of powder A, and evaluation was performed in the same manner as in Example 3. Table 5 shows the amount of each component added and the evaluation results. As shown in Table 5, when the powder D was used, the same results as when the powder A was used were obtained.

Example 7
Cr ₂ O ₃ , Co ₃ O ₄ or Fe ₂ O ₃ was used as a substitute for MnO, and Li ₂ O ₃ , Al ₂ O ₃ , Ge ₂ O ₂ or B ₂ O ₃ was used as a substitute for SiO ₂ . Except for this, a capacitor sample was prepared in the same manner as in Example 3 and evaluated in the same manner as in Example 3. The amount of each component added and the evaluation results are shown in Table 6.

As shown in Table 6, Cr ₂ O ₃ , Co ₃ O ₄ or Fe as an alternative to MnO
Using ₂ O _3, even when using the _{Li 2 O 3, Al 2 O} 3, Ge 2 O 2 or _B 2 _{O 3} as a substitute for SiO _2, it was confirmed that the same characteristics can be obtained.

Example 8
In the production method of the powder A of Example 3, different powders were prepared in the range where the value of α of (Ba _a Gd _b ) _α (Ti _c Zr _d Mg _e ) O ₃ was 0.08 to 1.20. A capacitor sample was prepared in the same manner as in Example 3 and evaluated in the same manner as in Example 3. Table 7 shows the amount of each component added and the evaluation results.

As shown in Table 7, it was confirmed that good characteristics were obtained when 1.00 ≦ α ≦ 1.15.

Example 9
A capacitor sample was prepared in the same manner as in Example 3 except that an oxide of Sm, Eu, Tb, or Dy was used as an alternative to Gd ₂ O ₃ , and evaluation was performed in the same manner as in Example 3. The amount of each component added and the evaluation results are shown in Table 8.

As shown in Table 8, it was confirmed that similar characteristics were obtained even when an oxide of Sm, Eu, Tb or Dy was used as an alternative to Gd ₂ O ₃ .

Example 10
First, Ba _n ZrO _{2 + n} , MgCO ₃ , Gd ₂ O ₃ , MnO, and SiO ₂ are prepared, these are mixed in a ball mill, and the resulting mixed powder is pre-calcined at 1000 ° C. to obtain an average particle size A 0.2 μm roasted powder was prepared. Next, the obtained roasted powder was wet pulverized with a ball mill for 15 hours together with Ba _m TiO _{2 + m} powder having an average particle diameter of 0.6 μm and dried to obtain a dielectric material. The powder obtained by this production method is designated as powder E.

A capacitor sample was prepared in the same manner as in Example 1 except that the powder E was used instead of the powder A, and evaluation was performed in the same manner as in Example 1. Table 9 shows the amount of each component added and the evaluation results.

  From Table 9, by setting the dielectric ceramic composition composition within the predetermined range of the present invention, the dielectric constant (εs), the capacity-temperature characteristic (TC), and the electrostriction amount are kept good, and the breakdown voltage (withstand voltage) is maintained. It was also confirmed that the high temperature accelerated life (HALT) can be improved.

FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention.

Explanation of symbols

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

Claims (3)

Ba _m TiO _{2 + m} (where m is 0.99 ≦ m ≦ 1.01),
Ba _n ZrO _{2 + n} (where n is 0.99 ≦ n ≦ 1.01),
Mg oxide,
R oxide (where 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) )When,
An oxide of at least one element selected from Mn, Cr, Co and Fe;
A dielectric ceramic composition comprising an oxide of at least one element selected from Si, Li, Al, Ge and B,
The ratio of each component in terms of oxide or composite oxide with respect to 100 moles of Ba _m TiO _{2 + m} ,
Ba _n ZrO _{2 + n} : 40 to 55 mol,
Mg oxide: 4 to 12 mol,
R oxide: 4 to 15 mol,
Mn, Cr, Co and Fe oxides: 0.5-3 mol,
Si, Li, Al, Ge and B oxides: 3-9 mol,
A dielectric ceramic composition. A dielectric ceramic composition having a first component represented by the general formula of (Ba _a R _b ) _α (Ti _c Zr _d Mg _e ) O ₃ ,
R in the above general formula is a rare earth element,
In the above general formula:
0.8 ≦ a ≦ 0.96,
0.04 ≦ b ≦ 0.2,
0.62 ≦ c ≦ 0.69 ,
0.24 ≦ d ≦ 0.39,
0.02 ≦ e ≦ 0.07 and 1 ≦ α ≦ 1.15,
Ba _m TiO _{2 + m} contained in the first component (where m is 0.99 ≦ m ≦ 1.01) per 100 moles,
0.5 to 3.0 mol of an oxide of at least one element selected from Mn, Cr, Co and Fe;
A dielectric ceramic composition further comprising 3 to 9 mol of an oxide of at least one element selected from Si, Li, Al, Ge, and B. Electronic component having a dielectric layer comprising a dielectric ceramic composition according to claim 1 or 2, and an internal electrode layer.

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