JP2007246347A - Electronic part, dielectric porcelain composition, and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dielectric porcelain composition which can be fired in a reducing atmosphere, is reduced in the electrostriction quantity during the electric voltage application, exhibits capacity-temperature characteristics satisfying X6S, realizes a high specific dielectric constant, and is improved in accelerated high temperature lifetime. <P>SOLUTION: The method for manufacturing the dielectric porcelain composition comprises using the powder in which BaTiO<SB>3</SB>, SrTiO<SB>3</SB>, and CaTiO<SB>3</SB>respectively substantially do not form a solid solution with each other, and are included in the form of the BaTiO<SB>3</SB>crystal particles, SrTiO<SB>3</SB>crystal particles, and CaTiO<SB>3</SB>crystal particles to form a composite structure and BaTiO<SB>3</SB>powder, SrTiO<SB>3</SB>powder, and CaTiO<SB>3</SB>powder are used as the raw materials of the main component, and two or three kinds including the BaTiO<SB>3</SB>powder among these are previously reacted with one or more kind selected from oxides of elements V, Ta, Nb, W, Mo and Cr. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a dielectric ceramic composition having resistance to reduction, a method for producing the same, and an electronic component such as a multilayer ceramic capacitor using the dielectric ceramic composition.

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

  At present, ferroelectric ceramic materials are generally used for small-sized and high-capacity ceramic capacitors. Such a ferroelectric ceramic material is accompanied by an electrostriction phenomenon in which mechanical distortion occurs when an electric field is applied. Therefore, when a voltage is applied to a ceramic capacitor using a ferroelectric ceramic material, the electrostriction phenomenon occurs. Vibration due to.

  In particular, such an electrostriction phenomenon can cause vibration of not only the capacitor itself but also the board and surrounding components when a ceramic capacitor is mounted on a circuit board. May emit a vibration sound having an audible frequency (20 to 20000 Hz). This vibration sound may be in a range that is uncomfortable for humans, and countermeasures have been required.

  On the other hand, for example, in Patent Document 1, in order to suppress the transmission of the vibration of the ceramic capacitor due to the electrostriction phenomenon to the substrate, the ceramic capacitor is provided with an electrode connection portion for connecting the external terminal electrode and the substrate, It has been proposed to provide a certain separation distance between the lower surface of the capacitor element body and the substrate.

  However, as described in this document, if a method of providing a certain separation distance by the electrode connecting portion is adopted, the manufacturing cost of the ceramic capacitor increases, and the height direction of the capacitor increases, resulting in a small size. Further improvement has been desired in view of the difficulty in making it easier.

  Patent Document 2 contains calcium titanate, strontium titanate, and barium titanate, and the compositional molar ratio of at least barium titanate is 0.3 or less with respect to these three compositional molar ratios. A dielectric ceramic composition comprising at least one crystal structure of a tetragonal crystal is disclosed. The dielectric ceramic composition described in this document is particularly intended to reduce third harmonic distortion (THD). However, the dielectric ceramic composition of this document is not sufficient for improving the above-described electrostriction phenomenon, and has a structure in which the main components calcium titanate, strontium titanate and barium titanate are dissolved in each other. Since it is employed, the capacity-temperature characteristic is not sufficient, and for example, the X6S characteristic of the EIA standard (−55 to 105 ° C., ΔC / C = within ± 22%) cannot be satisfied.

Further, Patent Document 3 discloses a first crystal particle having a composition (Ba, Ca) TiO ₃ and a composition (Ba, Ca) (Ti, A) O ₃ (where A is V, Nb, Ta, The ratio of the number of the second crystal particles to the total number of the first and second crystal particles is 20 Dielectric porcelain compositions that are ˜80% are disclosed. However, even the dielectric porcelain composition of this document is not sufficient for improving the above-described electrostriction phenomenon, and has a configuration in which two components of calcium titanate and barium titanate, which are the main components, are dissolved. Therefore, the capacity-temperature characteristic is inferior.

JP 2004-335963 A JP 2000-264729 A Japanese Patent Application Laid-Open No. 2005-28166

  The object of the present invention is that firing in a reducing atmosphere is possible, the amount of electrostriction at the time of voltage application is reduced, and the capacity-temperature characteristic is an X6S characteristic (−55 to 105 ° C., ΔC / C of EIA standard). It is an object of the present invention to provide a dielectric ceramic composition and a method for producing the same, which can satisfy the following conditions:

As a result of intensive studies to achieve the above object, the inventors of the present invention contain BaTiO ₃ , SrTiO ₃ and CaTiO ₃ as main components, and these do not substantially dissolve in each other, and the composite structure Two or three kinds of BaTiO ₃ powder containing BaTiO ₃ powder among BaTiO ₃ powder, SrTiO ₃ powder and CaTiO ₃ powder, which are used as a main component raw material when producing a dielectric ceramic composition forming By using it as a reactive powder reacted with one or more selected from oxides of each element of V, Ta, Nb, W, Mo and Cr, it was found that the above object can be achieved, and the present invention has been completed. It was.

That is, the method for producing a dielectric ceramic composition according to the present invention includes:
A main component comprising BaTiO ₃ , SrTiO ₃ and CaTiO ₃ ;
A method for producing a dielectric ceramic composition containing, as a subcomponent, at least one selected from oxides of elements of V, Ta, Nb, W, Mo and Cr,
The BaTiO ₃ , SrTiO ₃ and CaTiO ₃ constituting the main component are not substantially dissolved in each other, and are contained in the form of BaTiO ₃ crystal particles, SrTiO ₃ crystal particles and CaTiO ₃ crystal particles, Forming a composite structure,
As a raw material of the main component, BaTiO ₃ powder, SrTiO ₃ powder, and CaTiO ₃ powder are used,
As the BaTiO ₃ powder, a powder previously reacted with at least one selected from oxides of elements of V, Ta, Nb, W, Mo and Cr,
As at least one of the SrTiO ₃ powder and CaTiO ₃ powder, a powder that has been reacted with at least one selected from oxides of elements of V, Ta, Nb, W, Mo, and Cr in advance.
It is characterized by using each.

Preferably, one or more ratios selected from oxides of V, Ta, Nb, W, Mo, and Cr, which are reacted in advance with the BaTiO ₃ powder, SrTiO ₃ powder, and CaTiO ₃ powder, are Rbt, When Rst and Rct are used (however, the above Rbt, Rst, and Rct are in terms of each element of V, Ta, Nb, W, Mo, and Cr with respect to 100 mol of BaTiO _3, 100 mol of SrTiO _{3, and} 100 mol of CaTiO ₃ , respectively Rbt, Rst and Rct are
0.05 mol ≦ Rbt <2.2 mol,
0 mol ≦ Rst <1.6 mol,
0 mol ≦ Rct <1.0 mol,
Rst + Rct> 0 mol,
It is a relationship.

  Preferably, the oxide content of each element of V, Ta, Nb, W, Mo and Cr contained in the finally obtained dielectric ceramic composition is V, It is 0.02 mol or more and less than 0.40 mol in terms of each element of Ta, Nb, W, Mo and Cr.

Preferably, when the BaTiO _3, SrTiO ₃ and composition molar ratio of CaTiO ₃ which contained as a main component, indicated by a composition formula _{{(Ba x Sr y Ca z} ) O} m TiO 2, in the formula The symbols x, y, z and m are
0.19 ≦ x ≦ 0.23,
0.26 ≦ y ≦ 0.31,
0.46 ≦ z ≦ 0.54,
x + y + z = 1,
0.980 ≦ m ≦ 1.01,
It is.

  Preferably, the dielectric ceramic composition further includes an oxide of Mn as a subcomponent, and the content of the oxide of Mn is 0.3 to 0.3 mol in terms of MnO with respect to 100 mol of the main component. 1 mole.

Preferably, the dielectric ceramic composition further includes an Si oxide as a subcomponent, and the content of the Si oxide is 0.1 in terms of SiO _{2 with} respect to 100 mol of the main component. -0.5 mol.

The dielectric ceramic composition according to the present invention is manufactured by any one of the above methods. In the dielectric ceramic composition of the present invention, preferably, an average crystal particle diameter of the plurality of BaTiO ₃ crystal particles, SrTiO ₃ crystal particles and CaTiO ₃ crystal particles is 0.2 to 2 μm.

The electronic component according to the present invention has a dielectric layer made of any one of the above dielectric ceramic compositions.
In the electronic component of the present invention, preferably, the dielectric layer has a thickness of 2 to 20 μm. By setting the thickness of the dielectric layer in such a range, it can be used for medium withstand voltage applications having a high rated voltage (for example, 100 V or more). Although it does not specifically limit as an electronic component, 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 are illustrated.

In the present invention, the dielectric ceramic composition contains BaTiO ₃ , SrTiO ₃ and CaTiO ₃ as main components, and these do not substantially dissolve each other, and BaTiO ₃ crystal particles and SrTiO ₃ crystal particles And CaTiO ₃ crystal particles in the form of a composite structure. Therefore, it is possible to reduce the capacity-temperature characteristic (particularly, the EIA standard X6S characteristic) and the amount of electrostriction during voltage application.

Moreover, in the present invention, among BaTiO ₃ powder, SrTiO ₃ powder and CaTiO ₃ powder used as the main component raw material, two or three kinds containing BaTiO ₃ powder are preliminarily added to V, Ta, Nb, W, Mo and A method is used in which the powder is reacted with one or more selected from oxides of Cr elements. Therefore, it is possible to improve the high temperature accelerated lifetime while realizing a high relative dielectric constant while maintaining the above-mentioned characteristics satisfactorily.

For example, in the above-mentioned Patent Document 3 (Japanese Patent Laid-Open No. 2005-281666), (Ba, Ca) TiO ₃ crystal particles and (Ba, Ca) TiO ₃ with V or the like added thereto (Ba, Ca) ( A dielectric ceramic composition obtained by mixing Ti, A) O ₃ crystal particles (where A is one selected from V, Nb, Ta, Cr, Mo, and W) is disclosed. However, this Patent Document 3 differs from the present invention in that the dielectric ceramic composition is a solid solution of BaTiO ₃ and CaTiO ₃ . Furthermore, it is different from the present invention in that it does not contain SrTiO ₃ . Therefore, in Patent Document 3, it is impossible to obtain the effect of improving the relative dielectric constant and the effect of improving the high temperature accelerated lifetime as in the present invention.

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.

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 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 a dielectric ceramic composition obtained by the production method of the present invention.
The dielectric ceramic composition contained in the dielectric layer 2 includes a main component including BaTiO ₃ , SrTiO ₃ and CaTiO ₃ and oxides of V, Ta, Nb, W, Mo and Cr as subcomponents. One or more selected from.

In the present embodiment, the BaTiO ₃ , SrTiO ₃ and CaTiO ₃ constituting the main component are contained in a state where they are not substantially dissolved in each other. That is, in this embodiment, these BaTiO ₃ , SrTiO ₃ and CaTiO ₃ are contained as BaTiO ₃ crystal particles, SrTiO ₃ crystal particles and CaTiO ₃ crystal particles as separate crystal particles, respectively, and form a composite structure. .

However, BaTiO ₃ , SrTiO ₃ and CaTiO ₃ may be substantially contained as BaTiO ₃ crystal particles, SrTiO ₃ crystal particles and CaTiO ₃ crystal particles. For example, BaTiO ₃ crystal particles and SrTiO ₃ crystal particles In the vicinity of the interface, a part of the solid solution phase may be formed.

By making BaTiO ₃ , SrTiO ₃ and CaTiO ₃ into a state in which they are not substantially dissolved in each other and forming a composite structure, it is possible to improve the capacity-temperature characteristics while maintaining the dielectric constant, In particular, the X6S characteristic of the EIA standard (−55 to 105 ° C., ΔC / C = within ± 22%) can be satisfied. The reason for this is considered to be, for example, that the Curie temperature peak derived from BaTiO ₃ remains due to the non-solid solution and the composite structure.

Whether or not BaTiO ₃ , SrTiO ₃ and CaTiO ₃ constituting the main component are dissolved in each other can be confirmed by, for example, X-ray diffraction of the dielectric layer 2. Specifically, the dielectric layer 2 is subjected to X-ray diffraction using Cu-Kα ray as an X-ray source, and BaTiO ₃ , SrTiO ₃ and CaTiO ₃ are respectively obtained in the range of 2θ = 30 to 35 °. This can be confirmed by whether or not the resulting separable three diffraction peaks are observed. The diffraction peaks observed in the range of 2θ = 30 to 35 ° are the diffraction peak of the (110) plane of BaTiO ₃ , the diffraction peak of the (110) plane of SrTiO ₃ , and the (121) plane of CaTiO ₃ , respectively. It is a diffraction peak.

Further, when there is no particular limitation on the composition molar ratio of BaTiO _3, SrTiO ₃ and CaTiO ₃ that constitute the main component, showing them by a composition formula _{{(Ba x Sr y Ca z} ) O} m TiO 2, The symbols x, y, z and m in the above formula are preferably
0.19 ≦ x ≦ 0.23,
0.26 ≦ y ≦ 0.31,
0.46 ≦ z ≦ 0.54,
0.980 ≦ m ≦ 1.01,
And more preferably
0.195 ≦ x ≦ 0.225,
0.265 ≦ y ≦ 0.305,
0.465 ≦ z ≦ 0.535,
0.985 ≦ m ≦ 1.075,
It is. In the above formula, x + y + z = 1.
By making the symbols x, y, z, and m within the above ranges, it is possible to enhance the effect of improving the DC bias characteristics and the effect of reducing the amount of electrostriction during voltage application. In the above composition formula, the amount of oxygen (O) may be slightly deviated from the stoichiometric composition of the above formula.

In the above formula, x represents the content ratio of BaTiO ₃ . As the content of BaTiO _{3 in} the main component increases, the ferroelectricity tends to increase. If x is too small, the relative permittivity tends to be low. In particular, if the relative dielectric constant is too low, it is necessary to increase the number of laminated dielectric layers 2 in order to obtain a desired capacitance. Therefore, there arises a problem that it becomes difficult to reduce the size. On the other hand, if x is too large, although the relative permittivity is improved, the amount of electrostriction when a voltage is applied increases, and the DC bias characteristics tend to deteriorate.

In the above formula, y represents the content ratio of SrTiO ₃ . When the content of SrTiO _{3 in} the main component increases, the paraelectric property tends to increase. If y is too small, the dielectric constant tends to be low. On the other hand, if y is too large, the DC bias characteristics tend to deteriorate.

In the above formula, z indicates the content of CaTiO _3. CaTiO ₃ is mainly effect and of improving the sintering stability has the effect of improving the insulation resistance value. If z is too small, the DC bias characteristics tend to deteriorate. On the other hand, if z is too large, the dielectric constant tends to decrease.

When the content of BaTiO _{3 in} the main component increases, the ferroelectricity becomes stronger. On the other hand, when the content of SrTiO ₃ and CaTiO ₃ in the main component increases, the paraelectric property tends to increase, and the symbol x By setting, y, and z within the above ranges, a balance between the ferroelectric phase and the paraelectric phase can be achieved.

  In the above formula, m represents the ratio of the A site of the perovskite structure to the B site (ratio of Ba, Sr and Ca and Ti). By setting m to 0.980 or more, grain growth of dielectric particles during firing can be suppressed. Further, by setting m to 1.01 or less, a dense sintered body can be obtained without increasing the firing temperature. If m is too small, it is difficult to make the dielectric particles fine, and the DC bias characteristics tend to deteriorate. On the other hand, if m is too large, the sintering temperature becomes too high and sintering tends to be difficult.

The oxides of each element of V, Ta, Nb, W, Mo, and Cr as subcomponents have an effect of improving the high temperature accelerated life and an effect of reducing variations in the high temperature accelerated life between products. The content of these oxides is preferably 0.02 mol or more and less than 0.40 mol in terms of each oxide of V, Ta, Nb, W, Mo and Cr with respect to 100 mol of the main component. More preferably, it is 0.05-0.35 mol, More preferably, it is 0.1-0.3 mol. If the content of these oxides is too small, the above effect is difficult to obtain. On the other hand, if too much, IR tends to decrease.
In addition, the said content is content of each element conversion, for example, in the oxide of V, when content in V element conversion is 0.10 mol, it is V ₂ O ₅ which is the oxide The content in terms of conversion is 0.05 mol.
Further, as will be described later, in this embodiment, the oxides of these elements of V, Ta, Nb, W, Mo, and Cr are BaTiO ₃ powder, SrTiO ₃ powder, and CaTiO ₃ powder used as raw materials of the main component. Among them, the dielectric ceramic composition is made to react in advance with two or three kinds including BaTiO ₃ powder.

  In addition to the main component described above and one or more selected from oxides of each element of V, Ta, Nb, W, Mo and Cr, the dielectric ceramic composition includes an oxide of Mn Further, it is preferable to further contain an oxide of Si.

  The oxide of Mn has an effect of promoting sintering and an effect of improving the high temperature accelerated life. The content of the Mn oxide is preferably 0.3 to 1 mol and more preferably 0.3 to 0.8 mol in terms of MnO with respect to 100 mol of the main component. If the content of the Mn oxide is too small, the sinterability deteriorates and the high temperature accelerated life tends to be inferior. On the other hand, if the content is too large, the IR defect rate may deteriorate.

The Si oxide mainly acts as a sintering aid, but has an effect of improving the defective rate of the initial insulation resistance when the layer is thinned. The content of the Si oxide is preferably 0.1 to 0.5 mol and more preferably 0.15 to 0.45 mol in terms of SiO _{2 with} respect to 100 mol of the main component. If the content of Si oxide is too small, the firing temperature may increase. On the other hand, when the amount is too large, the IR defect rate tends to deteriorate.

In the present embodiment, Si oxide may be included in the form of a complex oxide. Examples of such composite oxides include composite oxides of SiO ₂ and oxides of elements constituting other main components and subcomponents contained in the dielectric ceramic composition. For example, CaSiO ₃ , SrSiO ₃ , (Ca, Sr) SiO ₃ , MnSiO ₃ , BaSiO _{3 and the} like. When these composite oxides are used, they may be appropriately adjusted so that the composition after firing falls within a desired range.

  Moreover, in this embodiment, you may contain subcomponents other than the above as needed. Such subcomponents are not particularly limited. For example, Ba, Ca, Sr, Li, Mg, Al, Zr, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb , Dy, Ho, Er, Tm, Yb, and Lu oxides.

The average crystal particle diameter of the BaTiO ₃ crystal particles, SrTiO ₃ crystal particles and CaTiO ₃ crystal particles constituting the dielectric layer 2 is preferably 0.2 to 2 μm. If the average crystal particle size is too small, the relative dielectric constant and the capacity-temperature characteristic tend to deteriorate. On the other hand, if it is too large, the high temperature load life tends to deteriorate.

  Although the thickness of the dielectric material layer 2 is not specifically limited, Preferably it is 2-20 micrometers, More preferably, it is 4-15 micrometers. By setting the thickness of the dielectric layer 2 in such a range, it is possible to correspond to a medium withstand voltage application having a high rated voltage (for example, 100 V or more). If the dielectric layer 2 is too thin, the short-circuit defect rate may deteriorate. On the other hand, if it is too thick, it is difficult to reduce the size of the capacitor.

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, Cu, Ni alloy or Cu alloy is preferable, and Ni or Ni alloy is particularly preferable. When the main component of the internal electrode layer 3 is Ni or a Ni alloy, it is preferable to fire at a low oxygen partial pressure (reducing atmosphere) so that the dielectric is not reduced. The thickness of the internal electrode layer 3 is preferably 0.5 to 2 μm, more preferably 0.8 to 1.5 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. 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 baking. 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, the above-mentioned main component and subcomponent oxides, mixtures thereof, and composite oxides can be used. In addition, various compounds that become the above oxides or composite oxides by firing, such as carbonic acid, can be used. A salt, an oxalate salt, a nitrate salt, a hydroxide, an organometallic compound, or the like can be selected as appropriate 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. 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 the present embodiment, BaTiO ₃ powder, SrTiO ₃ powder and CaTiO ₃ powder are used as the raw material of the main component, and these BaTiO ₃ powder, SrTiO ₃ powder and CaTiO ₃ powder are not reacted with each other in advance. Use. BaTiO ₃ , SrTiO _3, and SrTiO ₃ that constitute the main component in the sintered dielectric ceramic composition by using these powders as raw materials of the main component and using them without reacting with each other in advance. the CaTiO _3, each other, can be configured to not substantially dissolved. That is, in the sintered dielectric ceramic composition, these composite oxides can be present in the form of BaTiO ₃ crystal particles, SrTiO ₃ crystal particles, and CaTiO ₃ crystal particles to form a composite structure.

Furthermore, in the present embodiment, among these BaTiO ₃ powder, SrTiO ₃ powder and CaTiO ₃ powder, two or three kinds containing BaTiO ₃ powder are used as subcomponents, and V, Ta, A reaction powder (preferably a solid solution powder) obtained by reacting in advance with one or more elements selected from oxides of each element of Nb, W, Mo and Cr is used.

That is, in this embodiment, as the BaTiO ₃ powder, a powder that has been reacted with at least one element selected from oxides of elements of V, Ta, Nb, W, Mo, and Cr in advance is used, and SrTiO ₃ powder and As at least one of the CaTiO ₃ powders, a powder previously reacted with one or more selected from oxides of elements of V, Ta, Nb, W, Mo, and Cr is used.
In addition to the BaTiO ₃ powder, SrTiO ₃ powder and CaTiO ₃ powder are used as raw materials for the main component to be reacted with one or more elements selected from oxides of elements of V, Ta, Nb, W, Mo and Cr in advance. Either one or both of them may be used. Specifically, in addition to an embodiment in which two types of BaTiO ₃ powder and SrTiO ₃ powder are used as the reaction powder, an embodiment in which two types of BaTiO ₃ powder and CaTiO ₃ powder are used as the reaction powder, and in addition to the BaTiO ₃ powder, SrTiO ₃ is added. ₃ powder and aspects of using three kinds of CaTiO ₃ powder as a reaction powder.

Among BaTiO ₃ powder, SrTiO ₃ powder, and CaTiO ₃ powder, one or more selected from oxides of V, Ta, Nb, W, Mo, and Cr are used as two or three kinds including BaTiO ₃ powder. By using a reaction powder that has been reacted in advance, the high temperature accelerated life can be improved while maintaining other electrical characteristics such as the relative permittivity and the temperature characteristics of the capacitance in good condition. Furthermore, it is possible to improve the variation in the high temperature accelerated life between products.
The reason for this is that these main component raw materials are reacted with at least one of V, Ta, Nb, W, Mo and Cr (preferably, solid solution), so that these V, Ta, It is considered that the effect of adding Nb, W, Mo, Cr can be enhanced. Specifically, it is considered that cation vacancies can be formed more effectively and oxygen vacancies can be reduced.

On the other hand, when the raw material of the main component used as the reaction powder is only BaTiO ₃ powder, or only SrTiO ₃ powder and CaTiO ₃ powder, the above effect is insufficient, and the effect of improving the high temperature accelerated life is obtained. It becomes impossible.

The ratio of the oxides of the elements V, Ta, Nb, W, Mo, and Cr to be reacted in advance with the main component raw material is set when the ratios are Rbt, Rst, and Rct, respectively (however, Rbt, Rst, Rct may be set to the following ranges in the ratio of each element of V, Ta, Nb, W, Mo and Cr to 100 mol of BaTiO _3, 100 mol of SrTiO _{3 and} 100 mol of CaTiO ₃ , respectively. preferable.
That is, Rbt, Rst and Rct are preferably
0.05 mol ≦ Rbt <2.2 mol,
0 mol ≦ Rst <1.6 mol,
0 mol ≦ Rct <1.0 mol,
More preferably,
0.1 ≦ Rbt ≦ 1.5 mol,
0 mol ≦ Rst <1 mol,
0 mol ≦ Rct <0.8 mol,
It is. However, Rst and Rct are Rst + Rct> 0 mol.

  In the present embodiment, at least a part of the oxides of V, Ta, Nb, W, Mo, and Cr contained in the fired dielectric ceramic composition is preliminarily used as the main component raw material. It is sufficient to adopt a configuration in which the reaction is performed. In particular, the total amount of oxides of each element of V, Ta, Nb, W, Mo, and Cr contained in the dielectric ceramic composition after firing is used as a main component. It is preferable to react with these raw materials in advance. This is because the effect of these additions can be further enhanced by reacting the total amount of oxides of the respective elements of V, Ta, Nb, W, Mo and Cr in advance.

In addition, it does not specifically limit as a method of obtaining such reaction powder.
For example, when the case where BaTiO ₃ powder is used as a reaction powder is exemplified, BaTiO ₃ powder and oxides of each element of V, Ta, Nb, W, Mo and Cr are mixed by a ball mill, a bead mill, etc. A method of calcining at 1300 ° C. and causing a solid-phase reaction is mentioned. Alternatively, BaCO ₃ and TiO ₂ and oxides of each element of V, Ta, Nb, W, Mo, and Cr are similarly mixed, calcined at 700 to 1300 ° C., and subjected to solid phase reaction. It is done. By adopting such a method, the reaction can be made substantially uniform and a solid solution powder can be obtained.
Furthermore, SrTiO ₃ powder, even when the CaTiO ₃ powder The reaction powder, may be the same as in the case of BaTiO ₃ powder.

  Moreover, as raw materials other than the main component (for example, raw materials for subcomponents), each oxide or a compound that becomes each oxide by firing may be used as it is, or calcined in advance and used as roasted powder. It may be used.

  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. Further, the organic solvent 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. As the internal electrode layer paste, a commercially available electrode paste may be used, or a paste prepared from a commercially available electrode material may be used. In addition, the internal electrode layer paste may contain a co-material as necessary. As the co-material, a material having the same composition as the dielectric material contained in the dielectric layer paste (for example, BaTiO ₃ powder, SrTiO ₃ powder, CaTiO ₃ powder, etc.) may be used.

  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 ⁻⁹ to 10 ⁻¹⁴ Pa. 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 constituent material of the internal electrode layer, and the dielectric 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.

  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 ^{−1 to} 10 Pa. 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 accelerated life tends to be short. 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. Decreased acceleration life is likely to occur. 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.
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.

According to the present embodiment, the dielectric layer 2 of the multilayer ceramic capacitor contains BaTiO ₃ , SrTiO ₃ and CaTiO ₃ as main components, and these do not substantially dissolve in each other to form a composite structure. Of the BaTiO ₃ powder, SrTiO ₃ powder, and CaTiO ₃ powder used as the main component raw material, two or three kinds containing BaTiO ₃ powder are preliminarily made of each element of V, Ta, Nb, W, Mo and Cr. The method of making it react with 1 or more types selected from an oxide is employ | adopted. For this reason, the multilayer ceramic capacitor of this embodiment satisfies the X6S characteristic (−55 to 105 ° C., ΔC / C = ± 22% or less) of the capacitance temperature characteristic of EIA standard, and the amount of electrostriction when voltage is applied is reduced. In addition, the high temperature accelerated lifetime can be improved while realizing a high relative dielectric constant.

In the present embodiment, the electrostriction amount when the voltage is applied has the following characteristics.
That is, when the number of dielectric layers 2 sandwiched between the pair of internal electrode layers 3 is N, the ceramic capacitor is fixed to the substrate, and the multilayer ceramic capacitor 1 such as a glass epoxy substrate is mounted. A voltage defined by the vibration width of the surface of the element body 10 when a voltage is applied to a ceramic capacitor fixed on a normal substrate under the conditions of AC: 0.2 Vrms / μm, DC: 4 V / μm, and frequency: 1 kHz. The amount of strain can be preferably less than 0.125 N [nm], more preferably 0.1 N [nm] or less.
In particular, in the present embodiment, the amount of electrostriction when a voltage is applied can be within the above range while realizing a high dielectric constant of 500 or more.

  The values of AC and DC under the above voltage application conditions are applied voltages per 1 μm thickness of the dielectric layer. That is, for example, when the thickness of the dielectric layer is 5 μm, the applied voltage is AC: 1.0 Vrms (= 0.2 Vrms / μm × 5 μm) and DC: 20 V (= 4 V / μm × 5 μm). Further, the amount of electrostriction tends to change as the thickness of the dielectric layer 2 changes. Therefore, in this embodiment, when the thickness of the dielectric layer 2 is preferably 2 to 20 [mu] m, more preferably 4 to 15 [mu] m, and particularly 5 [mu] m, the predetermined range is preferable.

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

  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
Preparation of reaction powder First, BaTiO ₃ powder as a main component material and V ₂ O ₅ as a sub component material were prepared. Then, these BaTiO ₃ powder and V ₂ O ₅ were wet mixed in a ball mill for 15 hours, dried, and calcined at 1000 ° C. to prepare BaTiO ₃ powder previously reacted with V ₂ O ₅ . .
In this example, the amount (Rbt) of V ₂ O ₅ to be reacted with the BaTiO ₃ powder in advance is shown in Table 1 as the number of moles relative to 100 moles of the BaTiO ₃ powder. In Table 1, the number of moles of V ₂ O ₅ is represented by the number of moles of V element. For example, if Sample No. 2 in Table 1, the reaction of _V 2 _{O 5} reacted with BaTiO ₃ powder (Rbt), with respect to BaTiO ₃ powder 100 mol, 0.50 mol.

Further, in the same manner as described above, were prepared and SrTiO ₃ powder reacted with previously _V 2 _{O 5,} and CaTiO ₃ powder reacted with previously _V 2 _{O 5.} The amounts of V ₂ O ₅ (Rst, Rct) to be reacted with these SrTiO ₃ powder and CaTiO ₃ powder in advance are shown in Table 1 in terms of moles relative to 100 moles of BaTiO ₃ powder. In Table 1, the number of moles of V ₂ O ₅ is represented by the number of moles of V element. For example, if Sample No. 2 in Table 1, the amount of _V 2 _{O 5} reacted with SrTiO ₃ powder (Rst), against SrTiO ₃ powder 100 mol, and 0.16 mol, also a CaTiO ₃ powder The amount of V ₂ O ₅ to be reacted (Rct) was 0.09 mol with respect to 100 mol of CaTiO ₃ powder.

Preparation of Dielectric Layer Paste Next, BaTiO ₃ powder, SrTiO ₃ powder and CaTiO ₃ powder previously reacted with V ₂ O ₅ , MnCO ₃ and SiO ₂ as raw materials of subcomponents, A site of main component and As a raw material for adjusting the ratio of B site (Ba, Sr and Ca and Ti ratio), TiO ₂ was wet pulverized with a ball mill for 15 hours and dried to obtain a dielectric raw material. . In addition, the mixing ratio of each raw material was adjusted so that the composition after baking became the composition shown in Table 1. However, in Table 1, the addition amount of each subcomponent is the number of moles with respect to 100 moles of the main component, MnO and SiO ₂ are converted into oxides, and V ₂ O ₅ is converted into V element. Indicated. Moreover, MnCO ₃ which is a raw material of the subcomponent is a compound that becomes MnO after firing.

  Then, 100 parts by weight of the obtained dielectric material, 10 parts by weight of polyvinyl butyral resin, 5 parts by weight of dibutyl phthalate (DOP) as a plasticizer, and 100 parts by weight of alcohol as a solvent are mixed with a ball mill to obtain a paste. To obtain a dielectric layer paste.

A multilayer ceramic chip capacitor 1 shown in FIG. 1 was manufactured using the dielectric layer paste prepared above and the internal electrode layer paste prepared as described above. . In the present example, a commercially available capacitor electrode paste (a paste containing mainly Ni particles as conductive particles) was used as the internal electrode layer paste.

  First, a green sheet was formed on a PET film by the doctor blade method using the obtained dielectric layer paste. Next, an electrode pattern was printed on the green sheet by screen printing using the internal electrode layer paste to produce a green sheet on which the electrode pattern was printed. The thickness of the green sheet on which the electrode pattern was printed was 6.5 μm after drying. Next, separately from the above green sheet, a green sheet with no electrode pattern printed on the PET film was manufactured by a doctor blade method using the dielectric layer paste.

And each green sheet manufactured above was laminated | stacked in the following order, and the green chip | tip was manufactured by pressing the obtained laminated body.
That is, first, green sheets on which no electrode patterns were printed were laminated until the total thickness reached 300 μm. On top of that, five green sheets printed with electrode patterns were laminated. Further thereon, a green sheet on which no electrode pattern was printed was laminated until the total thickness reached 300 μm to obtain a laminate. The obtained laminate was heated and pressurized under the conditions of a temperature of 80 ° C. and a pressure of 1 t / cm ² to obtain a green chip.

Next, the obtained green chip was cut into a predetermined size and subjected to binder removal processing, firing and annealing under the following conditions to obtain a multilayer ceramic fired body.
The binder removal treatment conditions were temperature rising rate: 30 ° C./hour, holding temperature: 250 ° C., temperature holding time: 8 hours, and atmosphere: in the air.
Firing conditions are: temperature rising rate: 200 ° C./hour, holding temperature: 1240 ° C., temperature holding time: 2 hours, cooling rate: 200 ° C./hour, atmospheric gas: a mixed gas of humidified N ₂ and H ₂ (H ₂ : 3%).
The annealing condition was a Atsushi Nobori rate: 200 ° C. / hour, holding temperature: 1000 ° C., a temperature holding time: 2 hours, cooling rate: 200 ° C. / time, the atmospheric gas of a wet _{N 2} gas.
A wetter with a water temperature of 20 ° C. 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. The size of the obtained capacitor sample is 2.5 mm × 2.5 mm × 3.2 mm, the thickness of the dielectric layer is 5 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 4.
In this example, the amounts of V ₂ O ₅ (Rbt, Rst, Rct) reacted in advance with the BaTiO ₃ powder, SrTiO ₃ powder and CaTiO ₃ powder are the respective mole numbers shown in Table 1, Sample numbers 1 to 9 having components and subcomponents as shown in Table 1 were produced.

  About each obtained capacitor | condenser sample, the dielectric constant and the high temperature accelerated lifetime (HALT) were measured by the method shown below. The obtained results are shown in Table 1.

Dielectric constant ε
First, at a reference temperature of 25 ° C., a capacitor with a frequency of 1 kHz and an input signal level (measurement voltage) of 1.0 Vrms is input with a digital LCR meter (YHP 4284A), and the capacitance C is measured. did. Then, the relative dielectric constant ε (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. It is preferable that the relative dielectric constant is high. In this example, 500 or more was considered good. The results are shown in Table 1.

High temperature accelerated life (HALT )
The high temperature accelerated lifetime (HALT) was evaluated by maintaining the obtained sample at 175 ° C. in a DC voltage application state of 16 V / μm and measuring the average lifetime. In this example, the time from the start of application until the insulation resistance drops by two digits was defined as the lifetime. The high temperature accelerated life was evaluated for 10 capacitor samples and averaging the results. In this example, 1 hour or longer was considered good. The results are shown in Table 1.

  In this example, in addition to the above evaluation, the capacity-temperature characteristic (X6S characteristic) and the amount of electrostriction due to voltage application were measured and evaluated by the following methods. As a result, it was confirmed that each of the capacitor samples of this example satisfied the following standards.

Capacity-temperature characteristics (X6S characteristics)
For the capacitor sample, the capacitance at each temperature of −55 ° C., 25 ° C. and 105 ° C. was measured, and the change rate ΔC of the capacitance at −55 ° C. and 105 ° C. with respect to the capacitance at 25 ° C. (unit: %) Was calculated. In this example, a sample in which the rate of change in electrostatic capacitance satisfies the X6S characteristic of the EIA standard (−55 to 105 ° C., ΔC = within ± 22%) is considered good. As a result, in this example, all satisfied the X6S characteristic, and good results were obtained.

Electrostriction due to voltage application The electrostriction due to voltage application was measured by the following method. That is, first, the capacitor sample was fixed by soldering to a glass epoxy substrate on which electrodes having a predetermined pattern were printed. Next, a voltage is applied to the capacitor sample fixed on the substrate under the conditions of AC: 0.2 Vrms / μm, DC: 4 V / μm, and frequency: 1 kHz, and the vibration width of the capacitor sample surface during voltage application is measured. This was the amount of electrostriction. 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 amount of electrostriction is preferably low, and in this example, the electrostriction amount of each sample was 0.5 nm or less, which was a favorable result.

Table 1 shows the composition of the dielectric layers of Sample Nos. 1 to 9, the amount of V ₂ O ₅ (Rbt, Rst, Rct) previously reacted with BaTiO ₃ powder, SrTiO ₃ powder, CaTiO ₃ powder, and the respective characteristics. An evaluation result is shown. In Sample Nos. 1 to 9, the entire amount of V ₂ O ₅ to be contained in the dielectric layer was reacted in advance with BaTiO ₃ powder, SrTiO ₃ powder and CaTiO ₃ powder. Therefore, in each sample, the amount of V ₂ O ₅ contained in the dielectric layer is the number of moles of V ₂ O ₅ reacted with each main component material (Rbt, Rst, Rct) and the amount of each main component material. It becomes equal to what is calculated | required from a content rate.

From Table 1, sample characteristics Nos. 1 to 9 using BaTiO ₃ powder, SrTiO ₃ powder, and CaTiO ₃ powder previously reacted with V ₂ O ₅ as the main component raw material, each characteristic (capacitance-temperature characteristic and voltage application time) While keeping the electrostriction amount) in good condition, the high temperature accelerated lifetime (HALT) can be set to 1 hour or more while the relative dielectric constant is set to 500 or more.

Example 2
The amount of V ₂ O ₅ (Rbt, Rst, Rct) to be pre-reacted with the BaTiO ₃ powder, SrTiO ₃ powder and CaTiO ₃ powder is the number of moles shown in Table 2, respectively, and the main component and subcomponents are respectively Except for the compositions shown in Table 2, capacitor samples (sample numbers 11 to 18) were prepared in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Table 2.

In Table 2, sample numbers 11 to 14 are samples in which only two types of BaTiO ₃ powder and SrTiO ₃ powder were previously reacted with V ₂ O ₅ , and sample numbers 15 to 18 were BaTiO ₃ powder and It is a sample in which only two types of CaTiO ₃ powder are reacted with V ₂ O ₅ in advance.

Table 2 shows the composition of the dielectric layers of Sample Nos. 11 to 18, the amount of V ₂ O ₅ (Rbt, Rst, Rct) previously reacted with BaTiO ₃ powder, SrTiO ₃ powder, CaTiO ₃ powder, An evaluation result is shown. In Sample Nos. 11 to 18, the entire amount of V ₂ O ₅ contained in the dielectric layer was previously reacted with BaTiO ₃ powder, SrTiO ₃ powder, and CaTiO ₃ powder.
Sample Nos. 11 to 18 all had a capacity-temperature characteristic satisfying the X6S characteristic, and the electrostriction due to voltage application was 0.5 nm or less.

As shown in Table 2, when the reaction powder obtained by reacting only two kinds of BaTiO ₃ powder and SrTiO ₃ powder with V ₂ O ₅ in advance is used as the main component raw material, two kinds of BaTiO ₃ powder and CaTiO ₃ powder are used. Even when using the reaction powder previously reacted with V ₂ O ₅ alone, while maintaining each characteristic (capacitance-temperature characteristic and electrostriction amount at the time of voltage application) satisfactorily, while setting the relative dielectric constant to 500 or more It can be confirmed that the high temperature accelerated life (HALT) can be set to 1 hour or more, and good results can be obtained.

Example 3
The amount of V ₂ O ₅ (Rbt, Rst, Rct) to be pre-reacted with the BaTiO ₃ powder, SrTiO ₃ powder and CaTiO ₃ powder is the number of moles shown in Table 3, respectively, and the main component and subcomponents are respectively Capacitor samples (sample numbers 21 to 30) were produced in the same manner as in Example 1 except that the compositions shown in Table 3 were used, and evaluated in the same manner as in Example 1. The results are shown in Table 3.

In Table 3, sample number 21 is a sample in which none of BaTiO ₃ powder, SrTiO ₃ powder and CaTiO ₃ powder was reacted with V ₂ O _5, and sample numbers 22 to 27 were BaTiO ₃ powder, It is a sample in which only one kind of SrTiO ₃ powder and CaTiO ₃ powder is reacted with V ₂ O ₅ in advance.
Sample number 28 is a sample obtained by reacting only two types of SrTiO ₃ powder and CaTiO ₃ powder with V ₂ O ₅ in advance, and sample numbers 29 and 30 are V ₂ O ₅ added to the dielectric layer. Is a sample whose amount is outside the preferred range of the present invention.

Table 3 shows the composition of the dielectric layers of sample numbers 21 to 30, the amount of V ₂ O ₅ (Rbt, Rst, Rct) pre-reacted with BaTiO ₃ powder, SrTiO ₃ powder, CaTiO ₃ powder, and the respective characteristics. An evaluation result is shown.

From Table 3, it can be seen from Sample No. 21 that none of the BaTiO ₃ powder, SrTiO ₃ powder, and CaTiO ₃ powder was reacted with V ₂ O ₅ had a high temperature accelerated life (HALT) of less than 1 hour, resulting in a high temperature accelerated life. The result was inferior.
Furthermore, BaTiO ₃ powder, of SrTiO ₃ powder and CaTiO ₃ powder, one kind alone, _pre-V 2 _{O 5} and sample No. reacted 22 to 27, except the BaTiO ₃ powder, the SrTiO ₃ powder and CaTiO ₃ powder Similarly, in Sample No. 28 in which only two kinds were reacted with V ₂ O ₅ in advance, the high temperature accelerated life (HALT) was less than 1 hour, resulting in inferior high temperature accelerated life.
Furthermore, Sample Nos. 29 and 30 in which the amount of V ₂ O ₅ added to the dielectric layer was out of the preferred range of the present invention (that is, 0.40 mol or more) were too low in insulation resistance. A sample capable of evaluating the high temperature accelerated life (HALT) could not be obtained.

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 (9)

A main component comprising BaTiO ₃ , SrTiO ₃ and CaTiO ₃ ;
A method for producing a dielectric ceramic composition containing, as a subcomponent, at least one selected from oxides of elements of V, Ta, Nb, W, Mo and Cr,
The BaTiO ₃ , SrTiO ₃ and CaTiO ₃ constituting the main component are not substantially dissolved in each other, and are contained in the form of BaTiO ₃ crystal particles, SrTiO ₃ crystal particles and CaTiO ₃ crystal particles, Forming a composite structure,
As a raw material of the main component, BaTiO ₃ powder, SrTiO ₃ powder, and CaTiO ₃ powder are used,
As the BaTiO ₃ powder, a powder previously reacted with at least one selected from oxides of elements of V, Ta, Nb, W, Mo and Cr,
As at least one of the SrTiO ₃ powder and CaTiO ₃ powder, a powder that has been reacted with at least one selected from oxides of elements of V, Ta, Nb, W, Mo, and Cr in advance.
A method for producing a dielectric ceramic composition, characterized in that each is used. One or more ratios selected from oxides of V, Ta, Nb, W, Mo, and Cr, which are reacted in advance with the BaTiO ₃ powder, SrTiO ₃ powder, and CaTiO ₃ powder, are Rbt, Rst, and Rct, respectively. (Where Rbt, Rst, and Rct are ratios in terms of each element of V, Ta, Nb, W, Mo, and Cr with respect to 100 mol of BaTiO _3, 100 mol of SrTiO _{3, and} 100 mol of CaTiO ₃ , respectively) Rbt, Rst and Rct are
0.05 mol ≦ Rbt <2.2 mol,
0 mol ≦ Rst <1.6 mol,
0 mol ≦ Rct <1.0 mol,
Rst + Rct> 0 mol,
The method for producing a dielectric ceramic composition according to claim 1, wherein:   The oxide content of each element of V, Ta, Nb, W, Mo and Cr contained in the dielectric ceramic composition finally obtained is V, Ta, Nb with respect to 100 moles of the main component. 3. The method for producing a dielectric ceramic composition according to claim 1, wherein the amount is 0.02 mol or more and less than 0.40 mol in terms of each element of W, Mo, Cr. Said BaTiO _3, SrTiO ₃ and composition molar ratio of CaTiO ₃ which contained as a main component, in the case shown by a composition formula _{{(Ba x Sr y Ca z} ) O} m TiO 2, the symbols x in the above formulas, y, z and m are
0.19 ≦ x ≦ 0.23,
0.26 ≦ y ≦ 0.31,
0.46 ≦ z ≦ 0.54,
x + y + z = 1,
0.980 ≦ m ≦ 1.01,
The method for producing a dielectric ceramic composition according to any one of claims 1 to 3. The dielectric ceramic composition further includes an oxide of Mn as a subcomponent,
The method for producing a dielectric ceramic composition according to any one of claims 1 to 4, wherein a content of the oxide of Mn is 0.3 to 1 mol in terms of MnO with respect to 100 mol of the main component. . The dielectric ceramic composition further includes an oxide of Si as a subcomponent,
The dielectric ceramic composition according to any one of claims 1 to 5, wherein a content of the oxide of Si is 0.1 to 0.5 mol in terms of SiO _{2 with} respect to 100 mol of the main component. Manufacturing method.   A dielectric ceramic composition produced by the method according to claim 1. The dielectric ceramic composition according to claim 7, wherein an average crystal particle diameter of the plurality of BaTiO ₃ crystal particles, SrTiO ₃ crystal particles, and CaTiO ₃ crystal particles is 0.2 to 2 μm. An electronic component comprising a dielectric layer composed of the dielectric ceramic composition according to claim 7 or 8, wherein the dielectric layer has a thickness of 2 to 20 µm.

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