JP2007258477A - Laminated electronic component and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated electronic component which can be baked in a reductive atmosphere, has excellent DC bias characteristics, has decreased electrostriction quantity when a voltage is applied, and further, has an improved relative permittivity and capacitive temperature characteristics. <P>SOLUTION: The laminated electronic component has a dielectric layer and an internal electrode layer, wherein the dielectric layer consists of a dielectric porcelain composition containing BaTiO<SB>3</SB>, SrTiO<SB>3</SB>and CaTiO<SB>3</SB>as main components, and forming a composite structure in which these BaTiO<SB>3</SB>, SrTiO<SB>3</SB>and CaTiO<SB>3</SB>do not substantially form a solid solution with each other but contained as a form of a plurality of BaTiO<SB>3</SB>crystal particles, SrTiO<SB>3</SB>crystal particles and CaTiO<SB>3</SB>crystal particles, and in the dielectric layer, the difference (A<SB>BT</SB>-B<SB>BT</SB>) between a proportion A<SB>BT</SB>[%] of BaTiO<SB>3</SB>crystal particles in electrode contact particles 2a as particles directly contacting the internal electrode layer 3 and a proportion B<SB>BT</SB>[%] of BaTiO<SB>3</SB>crystal particles in non-electrode contact particles 2b as particles not contacting the internal electrode layer 3 is 5% or more. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a multilayer electronic component such as a multilayer ceramic capacitor and a manufacturing method thereof.

  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 demand for further miniaturization, larger capacity, lower cost, and higher reliability of multilayer ceramic capacitors has 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.

  In general, a multilayer ceramic capacitor having the above-described configuration is generally formed by printing an electrode paste for forming an internal electrode in a predetermined pattern on a ceramic green sheet mainly composed of ceramic powder and a binder, and then simultaneously firing them. Then, it is integrally sintered, and finally an external electrode is formed. As the conductive material for the internal electrode, Pd or Pd alloy is used. However, since Pd is expensive, a relatively inexpensive base metal such as Ni or Ni alloy has been used. However, base metals such as Ni and Ni alloys have the property of being sintered at a lower temperature than the dielectric powder constituting the dielectric layer. Therefore, for example, as in Patent Documents 3 and 4, in order to bring the sintering behavior of the internal electrode layer closer to the sintering behavior of the dielectric layer, ceramic powder as a co-material is used as an electrode paste for forming the internal electrode. A method of adding is known.

JP 2004-335963 A JP 2000-264729 A JP 2003-68559 A JP 2005-101318 A

  The object of the present invention is that firing in a reducing atmosphere is possible, the DC bias characteristics (dependence of the dielectric constant on the DC voltage application) are good, the amount of electrostriction during voltage application is reduced, and An object of the present invention is to provide a multilayer electronic component with improved relative permittivity and capacitance-temperature characteristics, and a method for manufacturing the same.

As a result of intensive studies to achieve the above object, the present inventors have made BaTiO ₃ , SrTiO _3, and CaTiO ₃ as main components of a dielectric layer constituting a multilayer electronic component such as a multilayer ceramic capacitor. And these are not substantially dissolved in each other to form a composite structure, and BaTiO _{3 with} respect to the total number of BaTiO ₃ crystal particles, SrTiO ₃ crystal particles and CaTiO ₃ crystal particles constituting the dielectric layer. Regarding the ratio of the number of crystal particles, the above object can be achieved by making a predetermined relationship between the ratio in the particles in contact with the internal electrode layer and the ratio in the particles not in contact with the internal electrode layer. As a result, the present invention has been completed.

That is, the multilayer electronic component according to the present invention is
Having a configuration in which dielectric layers and internal electrode layers are alternately laminated;
The dielectric layer contains BaTiO ₃ , SrTiO _3, and CaTiO ₃ as main components, and the BaTiO ₃ , SrTiO _3, and CaTiO ₃ are not substantially dissolved in each other, and a plurality of BaTiO ₃ Consists of a dielectric ceramic composition that is contained in the form of crystal particles, SrTiO ₃ crystal particles and CaTiO ₃ crystal particles and forms a composite structure,
The plurality of BaTiO ₃ crystal particles, SrTiO ₃ crystal particles, and CaTiO ₃ crystal particles constituting the dielectric layer are particles that are in direct contact with the internal electrode layer, and particles that are not in contact with the internal electrode layer. Consists of
When the particles that are in direct contact with the internal electrode layer are electrode contact particles, and the particles that are not in contact with the internal electrode layer are non-electrode contact particles, BaTiO ₃ crystal particles, SrTiO in the electrode contact particles A _BT [%] indicating the percentage of the number of BaTiO ₃ crystal particles as a percentage of the total number of ₃ crystal particles and CaTiO ₃ crystal particles,
Difference between B _BT [%], which is a percentage of the number of BaTiO ₃ crystal particles with respect to the total number of BaTiO ₃ crystal particles, SrTiO ₃ crystal particles, and CaTiO ₃ crystal particles in the non-electrode contact particles. (A _BT −B _BT ) is 5% or more.

Preferably, the difference between the _{A BT} and _{B BT (A BT -B BT)} is 40% or less.

Preferably, an average crystal particle diameter of the plurality of BaTiO ₃ crystal particles, SrTiO ₃ crystal particles, and CaTiO ₃ crystal particles constituting the dielectric layer is 0.2 to 2 μm.

  Preferably, the dielectric layer has a thickness of 2 to 20 μm.

Preferably, said BaTiO _3, SrTiO ₃ and CaTiO compositional molar ratio of ₃ contained as the main component in the dielectric ceramic composition, indicated by a composition formula _{{(Ba x Sr y Ca z} ) O} m TiO 2 Where the symbols x, y, z and m in the above formula are
0.19 ≦ x ≦ 0.23,
0.25 ≦ 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.

  Preferably, the dielectric ceramic composition further includes at least one selected from oxides of V, Ta, Nb, W, Mo, and Cr as subcomponents, and the V, Ta, Nb, Content of oxides of W, Mo and Cr is 0.02 mol or more and less than 0.40 mol in terms of each element of V, Ta, Nb, W, Mo and Cr with respect to 100 mol of the main component. It is.

In addition, a method for manufacturing a multilayer electronic component according to the present invention includes:
A method of manufacturing a multilayer electronic component having a configuration in which dielectric layers and internal electrode layers are alternately laminated,
A step of forming a green sheet to be a dielectric layer after firing, a step of forming an electrode paste film to be an internal electrode layer after firing by using an electrode paste, and alternately laminating the green sheet and the electrode paste film, A step of obtaining a green chip, and a step of firing the green chip,
The fired dielectric layer contains, as main components, BaTiO ₃ , SrTiO ₃ and CaTiO ₃ , and the BaTiO ₃ , SrTiO ₃ and CaTiO ₃ are not substantially dissolved in each other. A dielectric ceramic composition containing a BaTiO ₃ crystal particle, a SrTiO ₃ crystal particle, and a CaTiO ₃ crystal particle in the form of a composite structure,
As the electrode paste for forming the electrode paste film, an electrode paste containing a conductor powder and a common material containing BaTiO ₃ powder is used.

  In the manufacturing method of this invention, Preferably, content of the said common material in the said electrode paste is 1-30 weight part with respect to 100 weight part of said conductor powders.

  In the manufacturing method of the present invention, preferably, the dielectric ceramic composition constituting the dielectric layer has the same configuration as the multilayer electronic component of the present invention.

  The multilayer electronic component of the present invention and the multilayer electronic component obtained by the manufacturing method of the present invention are not particularly limited, but include multilayer ceramic capacitors, piezoelectric elements, chip inductors, chip varistors, chip thermistors, chip resistors, and the like. A surface mount (SMD) chip type electronic component is exemplified.

According to the present invention, the dielectric ceramic includes a dielectric layer containing BaTiO ₃ , SrTiO _3, and CaTiO ₃ as main components, and these are not substantially dissolved in each other to form a composite structure. It is composed of a composition. Therefore, it is possible to improve the relative permittivity, the DC bias characteristic, and the capacitance temperature characteristic, and to reduce the amount of electrostriction when a voltage is applied.

Moreover, in the present invention, among the BaTiO ₃ crystal particles, SrTiO ₃ crystal particles, and CaTiO ₃ crystal particles forming the composite structure, the abundance ratio of the BaTiO ₃ crystal particles is controlled as follows. That is, the ratio A _BT [%] of the number of BaTiO ₃ crystal particles in the electrode contact particles that are particles that are in direct contact with the internal electrode layer, and the non-electrode contact particles that are not in contact with the internal electrode layer The difference (A _BT −B _BT ) between the ratio B _BT [%] of the number of BaTiO ₃ crystal particles in the medium is 5% or more. Therefore, it is possible to further improve the relative dielectric constant and the capacity temperature characteristic while maintaining the above-mentioned characteristics satisfactorily. In particular, the capacity temperature characteristic can satisfy the X6S characteristic of the EIA standard.

Further, according to the manufacturing method of the present invention, the dielectric layer is composed of a dielectric ceramic composition forming a composite structure containing BaTiO ₃ , SrTiO ₃ and CaTiO ₃ , and after firing, the internal electrode layer and An electrode paste film is formed using an electrode paste containing BaTiO ₃ powder as a co-material. By adopting such a configuration, the ratio A _BT of the number of BaTiO ₃ crystal particles in the electrode contact particles and the ratio B _BT of the number of BaTiO ₃ crystal particles in the non-electrode contact particles are determined as described above. Thus, the same effects as described above can be obtained.

For example, in the above-mentioned Patent Document 3 (Japanese Patent Laid-Open No. 2003-68559), a composite composed of BCT type crystal particles containing Ba, Ca and Ti and BT type crystal particles containing Ba and Ti. In a multilayer ceramic capacitor having a dielectric layer forming a structure, a method is disclosed in which an internal electrode is formed using an electrode paste containing (Ba, Ca) TiO ₃ crystal powder as a co-material. However, in Patent Document 3, the crystal particles constituting the dielectric layer have a composite structure, but the type of dielectric particles constituting the composite structure is different from the present invention. Also, (Ba, Ca) TiO ₃ crystal powder is used as a co-material contained in the electrode paste, which is also different from the present invention in this respect. Therefore, in this patent document 3, there cannot be an effect like the manufacturing method of the above-mentioned this invention.

Further, in Patent Document 4 (Japanese Patent Laid-Open No. 2005-101318) described above, from crystal grains in which Ba and Ca as A site components and Ti and Zr as B site components are dissolved as main components, respectively. In a multilayer ceramic capacitor having a dielectric layer configured, a method of forming an internal electrode using an electrode paste containing BaTiO ₃ powder, BaZrO ₃ powder and CaZrO ₃ powder as a co-material is disclosed. However, this Patent Document 4 is different from the present invention in that BaZrO ₃ powder and CaZrO ₃ powder are used in addition to BaTiO ₃ powder as a co-material contained in the electrode paste. Further, the crystal particles constituting the dielectric layer are not formed of a composite structure but are formed of a solid solution, which is also different from the present invention in this respect. Therefore, in this patent document 4, the effect like the manufacturing method of the above-mentioned this invention cannot be show | played.

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.
FIG. 2 is a diagram for explaining the ratio of the number of BaTiO ₃ crystal particles in the electrode contact particles and the ratio of the number of BaTiO ₃ crystal particles in the non-electrode contact particles.

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.
The dielectric ceramic composition contained in the dielectric layer 2 has a main component including BaTiO ₃ , SrTiO ₃ and CaTiO ₃ .

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.

Furthermore, in the present embodiment, the ratio (number ratio) of the BaTiO ₃ crystal particles in the three types of crystal particles of the BaTiO ₃ crystal particles, SrTiO ₃ crystal particles, and CaTiO ₃ crystal particles constituting the dielectric layer 2 is as follows. The configuration is as follows.
That is, as shown in FIG. 2, when the crystal particles that are in direct contact with the internal electrode layer 3 are electrode contact particles 2a and the crystal particles that are not in contact with the internal electrode layer 3 are non-electrode contact particles 2b, to a ratio of BaTiO ₃ crystal grains in the electrode contact particles 2a in the ratio of BaTiO ₃ crystal grains in the non-electrode-contact particles 2b, and a predetermined relationship.

FIG. 2 is a diagram for explaining the ratio of the number of BaTiO ₃ crystal particles in the electrode contact particles and the ratio of the number of BaTiO ₃ crystal particles in the non-electrode contact particles. FIG. 3 is a view corresponding to an enlarged part of a cross section of a dielectric layer 2 sandwiched between layers 3. In FIG. 2, the electrode contact particles are denoted by reference numeral “2a”, the non-electrode contact particles are denoted by reference numeral “2b”, and different parallel oblique lines (hatching) are given to the sections thereof. However, these particles 2a and 2b are the same in that they are composed of any one of BaTiO ₃ crystal particles, SrTiO ₃ crystal particles, and CaTiO ₃ crystal particles. It is the schematic diagram which made the parallel oblique line (hatching) differ according to whether it is contacting. In FIG. 2, for example, the electrode contact particle 2 a is illustrated as the same electrode contact particle 2 a regardless of the composition (that is, BaTiO ₃ , SrTiO ₃ , or CaTiO ₃ ). (This also applies to the non-electrode contact particles 2b).

Specifically, in the present embodiment, BaTiO ₃ crystals with respect to the total number of BaTiO ₃ crystal particles, SrTiO ₃ crystal particles, and CaTiO ₃ crystal particles that constitute the electrode contact particles 2 a that are in direct contact with the internal electrode layer 3. the ratio of the number of particles and _a BT [%], BaTiO ₃ crystal grains constituting the non-electrode contact particles 2b, to the total number of SrTiO ₃ crystal grains and CaTiO ₃ crystal grains, the ratio of the number of BaTiO ₃ crystal grains In the case of B _BT [%], these differences (A _BT −B _BT ) are 5% or more.

That is, in the present embodiment, the ratio A _BT of the number of BaTiO ₃ crystal particles in the electrode contact particle 2a is higher than the ratio B _BT of the number of BaTiO ₃ crystal particles in the non-electrode contact particle 2b, and the difference Is 5% or more. By making the ratio of the BaTiO ₃ crystal particles in the electrode contact particles 2a and the non-electrode contact particles 2b in such a relationship, the DC bias characteristics are improved and the amount of electrostriction during voltage application is reduced. Further, it is possible to further improve the relative dielectric constant and the capacitance temperature characteristic (particularly the temperature characteristic on the low temperature side). In particular, in the present embodiment, the relative dielectric constant can be increased to 480 or more while the DC bias characteristic and the electrostriction amount are good, and the capacitance temperature characteristic satisfies the X6S characteristic of the EIA standard. be able to.

A _BT −B _BT, which is a difference between the ratio A _BT of the number of BaTiO ₃ crystal particles in the electrode contact particle 2 a and the ratio B _BT of the number of BaTiO ₃ crystal particles in the non-electrode contact particle 2 b, is 5%. Or more, preferably 5% or more and 35% or less. When A _BT -B _BT is too small, the relative dielectric constant is lowered and the capacity-temperature characteristic (particularly, the temperature characteristic on the low temperature side) is deteriorated.

The ratio _{A BT} of the number of BaTiO ₃ crystal grains in the electrode contact particles 2a, for example, can be determined as follows.
That is, first, SEM observation is performed on the cross section of the dielectric layer 2 to obtain an SEM image (reflection electron image) of the dielectric layer 2. And the particle | grains which are directly contacting the internal electrode layer 3 in the dielectric material layer 2 are specified from an SEM image (reflection electron image), and let this be the electrode contact particle 2a. For each of the particles constituting the identified electrode contact particles 2a, BaTiO ₃ crystal grains, to identify whether it is a SrTiO ₃ crystal grains and CaTiO ₃ crystal grains. Based on the results, the following equation (1) it is possible to find the ratio _{A BT} of the number of BaTiO ₃ crystal grains in the electrode contact particles 2a. When determining the ratio _ABT , it is preferable to perform the above measurement using at least 15 electrode contact particles 2a.
Ratio A _BT [%] = (Number of BaTiO ₃ crystal particles) / (Total number of BaTiO ₃ crystal particles, SrTiO ₃ crystal particles and CaTiO ₃ crystal particles) × 100 (1)

Note that each particle constituting the electrode contact particles 2a, BaTiO ₃ crystal grains, is whether it is a SrTiO ₃ crystal grains and CaTiO ₃ crystal grains, SEM image from (reflection electron image), the crystal grains Ba, Sr , Ca can be specified by measuring which is mainly contained.

The ratio B _BT of the number of BaTiO ₃ crystal particles in the non-electrode contact particles 2b is measured for the non-electrode contact particles 2b that are particles that are not in contact with the internal electrode layer 3 in the dielectric layer 2. Other than the above, it can be obtained in the same manner. In this case, in the SEM image (reflected electron image), a straight line passing through 15 or more non-electrode contact particles 2b is drawn, and the type of each particle is specified for the non-electrode contact particles 2b on the straight line. It is preferable to adopt the method.

The average crystal particle size of the electrode contact particles 2a and the non-electrode contact particles 2b constituting the dielectric layer 2 (that is, all BaTiO ₃ crystal particles, SrTiO ₃ crystal particles and CaTiO ₃ crystal particles constituting the dielectric layer 2) is The thickness is preferably 0.2 to 2 μm, more preferably 0.5 to 1.5 μm. If the average crystal particle diameter is too small, the relative dielectric constant may be lowered, or the capacity-temperature characteristic may be deteriorated. On the other hand, if it is too large, the high temperature load life tends to deteriorate.

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,
0.25 ≦ y ≦ 0.31,
0.46 ≦ z ≦ 0.54,
0.980 ≦ m ≦ 1.01,
And more preferably
0.195 ≦ x ≦ 0.225,
0.255 ≦ 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 dielectric ceramic composition preferably further contains subcomponents in addition to the main components described above.
In the present embodiment, as subcomponents, an oxide of Mn, an oxide of Si, and at least one selected from oxides of elements of V, Ta, Nb, W, Mo, and Cr are further included. It is preferable to contain.

  The oxide of Mn has the effect of promoting sintering and the effect of improving the high temperature load 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 load 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.

The oxides of each element of V, Ta, Nb, W, Mo, and Cr have an effect of improving the high temperature load life. 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 0.03-0.30 mol, More preferably, it is 0.05-0.20 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.

  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.

  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.

Preparation of Dielectric Paste First, a dielectric material (dielectric ceramic composition powder) contained in the dielectric paste is prepared, and this is made into a paint to prepare a dielectric paste.
The dielectric 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, as a material of the main component, BaTiO ₃ powder, it is preferable to use SrTiO ₃ powder and CaTiO ₃ powder, in particular, those BaTiO ₃ powder, SrTiO ₃ powder, CaTiO ₃ powder, pre-reacted with each other It is preferable to use without making it. 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.

In addition, BaTiO ₃ powder, SrTiO ₃ powder, and CaTiO ₃ powder as the main component raw material are not only so-called solid phase methods but also various liquid phase methods (for example, oxalate method, hydrothermal synthesis method, alkoxide method, sol-gel method, etc. ).
In addition to the above-mentioned powders, the raw material for the main component is TiO in order to adjust the ratio between the A site and the B site of the perovskite structure (ratio of Ba, Sr and Ca and Ti). ₂ may be further added.

  In addition, as raw materials other than the main components (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 and roasted in advance. It may be used as

  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 ordinary various binders such as ethyl cellulose, butyral resin, and acrylic resin. Moreover, the organic solvent to be used is not particularly limited, and may be appropriately selected from various organic solvents such as terpineol, acetone, toluene, ethanol, xylene, and the like according to a method to be used such as a printing method or a sheet method.

  Further, when the dielectric 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.

Preparation of electrode paste Next, an electrode paste is prepared to form the internal electrode layer 3 shown in FIG. 1 after firing.
As an electrode paste for forming the internal electrode layer 3, a paste containing a conductor powder, a common material, and an organic vehicle is used.

  Although it does not specifically limit as conductor powder, It is preferable to comprise by at least 1 sort (s) chosen from Cu, Ni, and these alloys, More preferably, it comprises Ni or Ni alloy.

  Ni or an Ni alloy is preferably an alloy of Ni and at least one element 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, Fe, and Mg, may be contained about 0.1 wt% or less.

In the present embodiment, a material containing BaTiO ₃ powder is used as the common material.
By using a material containing BaTiO ₃ powder as the co-material, the ratio A _BT of the number of BaTiO ₃ crystal particles in the electrode contact particles 2a and the ratio B of the number of BaTiO ₃ crystal particles in the non-electrode contact particles 2b and _BT, the difference of _{(a BT -B} BT), can be controlled in the above range. For this reason, for example, BaTiO ₃ powder as a co-material contained in the electrode paste is sintered in the vicinity of the interface between the internal electrode layer 3 and the dielectric layer 2 during firing, and after firing, This is considered to be due to the presence of the electrode contact particles 2a. Then, due to the effect of the BaTiO ₃ powder as the co-material, the ratio A _BT of the number of BaTiO ₃ crystal particles in the electrode contact particle 2a is higher than the ratio B _BT of the number of BaTiO ₃ crystal particles in the non-electrode contact particle 2b. Will be higher.

In addition to the BaTiO ₃ powder, the common material may contain SrTiO ₃ powder, CaTiO ₃ powder, or the like as necessary.

The content of the common material in the electrode paste is preferably 1 to 30 parts by weight, more preferably 5 to 25 parts by weight with respect to 100 parts by weight of the conductor powder. If the content of the co-material is too small, the difference in shrinkage behavior between the internal electrode layer and the dielectric layer during firing becomes large, and structural defects such as cracks are likely to occur. Further, the difference (A _BT −B _BT ) between the ratio A _BT and the ratio B _BT becomes small, and the above-mentioned effect tends not to be obtained. On the other hand, when there is too much content of a common material, a capacity temperature characteristic and a high temperature accelerated lifetime will deteriorate. In addition, the difference (A _BT −B _BT ) between the ratio A _BT and the ratio B _BT becomes too large, and the above effect tends not to be obtained. The average particle size of the co-material is not particularly limited, but the particle size after pulverization is preferably 0.01 to 1 μm.

  As the organic vehicle, the same one as the above-described dielectric paste may be used.

The electrode paste can be formed by mixing the above-described components with a ball mill, a three-roll mill, or the like to form a slurry. Alternatively, it may be employed a method of adding a common material including BaTiO ₃ powder in commercial electrode paste.

Preparation of Green Chip, baking, etc. Then, by using the dielectric paste prepared in the above, by a doctor blade method, on a carrier sheet, to form a ceramic green sheet. The ceramic green sheet becomes the dielectric layer 2 shown in FIG. 1 after firing.

  As the carrier sheet, for example, a PET film or the like is used, and a film coated with silicone or the like is preferable in order to improve peelability. Although the thickness of a carrier sheet is not specifically limited, Preferably it is 5-100 micrometers.

  A predetermined pattern of electrode paste film (internal electrode pattern) that becomes the internal electrode layer 3 shown in FIG. 1 after firing on the surface of the ceramic green sheet formed on the carrier sheet using the electrode paste prepared above. Form.

  The method for forming the electrode paste film is not particularly limited as long as it is a method capable of forming a layer uniformly, and examples thereof include a screen printing method.

Next, a plurality of ceramic green sheets having a predetermined pattern of electrode paste film formed on the surface are stacked to produce a green chip.
Then, before the 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 ⁻¹⁰ to 10 ⁻³ 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 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.
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 is composed of the above-described dielectric ceramic composition. Specifically, first, BaTiO ₃ , SrTiO _3, and CaTiO ₃ are included as main components, and these are not substantially dissolved in each other, and a plurality of BaTiO ₃ crystal particles, SrTiO ₃ crystal particles, and The composite structure contained in the form of CaTiO ₃ crystal particles is formed. Then, the second, the electrode contact particles 2a in a particle is in direct contact with the internal electrode layer 3, and the ratio A _BT of the number of BaTiO ₃ crystal particles, a particle that is not in contact with the internal electrode layers 3 The difference (A _BT −B _BT ) between the ratio of the number of BaTiO ₃ crystal particles B _{BT in the} non-electrode contact particles 2 b (A _BT −B _BT ) is within a predetermined range. Therefore, it is possible to improve the relative permittivity and the capacitance temperature characteristic (particularly the temperature characteristic on the low temperature side) while improving the DC bias characteristic and reducing the amount of electrostriction when a voltage is applied. In particular, while making the DC bias characteristic and the amount of electrostriction favorable, the relative dielectric constant can be increased to 480 or more, and the capacitance temperature characteristic can satisfy the X6S characteristic of the EIA standard.

In the present embodiment, while realizing a high dielectric constant of 480 or more, 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.

  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 multilayer electronic component according to the present invention. However, the multilayer electronic component according to the present invention is not limited to the multilayer ceramic capacitor and has the above-described 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 Dielectric Paste First, BaTiO ₃ powder, SrTiO ₃ powder and CaTiO ₃ powder are used as the main component materials, and MnCO ₃ , V ₂ O ₅ and SiO ₂ are used as the main component materials. TiO ₂ was prepared as a raw material for adjusting the ratio of B, B (Ba, Sr and Ca and Ti). In addition, MnCO ₃ which is a raw material of the subcomponent is a compound that becomes MnO after firing.

Subsequently, each raw material prepared above was wet pulverized with a ball mill for 15 hours and dried to obtain a dielectric 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.

  Next, 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. Dielectric paste was obtained.

Preparation of electrode paste First, Ni powder as a conductor powder and BaTiO ₃ powder as a co-material were prepared. Then, a Ni powder, a BaTiO ₃ powder, an organic vehicle, were mixed by a ball mill to form a paste to obtain an electrode paste. In this example, each electrode paste was prepared so that the content of the co-material with respect to 100 parts by weight of Ni powder would be the amount shown in Table 1.

Production of Multilayer Ceramic Capacitor Sample The multilayer ceramic capacitor 1 shown in FIG. 1 was produced using the dielectric paste produced above and the electrode paste as follows.

  First, a green sheet was formed on a PET film by the doctor blade method using the obtained dielectric paste. Next, an electrode pattern was printed on the green sheet by screen printing using an electrode 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 on which no electrode pattern was printed on the PET film was manufactured by a doctor blade method using a dielectric 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.
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 Samples 1 to 9 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.

For each of the obtained capacitor samples were measured by the method shown dielectric constant, the difference _A BT _{-B BT} of the capacitance-temperature characteristic (X6S characteristic) and the ratio _{A BT} and the ratio _{B BT} 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, 480 or more was considered good. The results are shown in Table 1.

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. The results are shown in Table 1. In Table 1, the rate of change in capacitance at −55 ° C. and the rate of change in capacitance at 105 ° C. are shown.

Difference between the ratio A _BT and the ratio B _BT A _BT -B _BT
A _BT −B _BT, which is the difference between the ratio A _BT of the number of BaTiO ₃ crystal particles in the electrode contact particle 2a and the ratio B _BT of the number of BaTiO ₃ crystal particles in the non-electrode contact particle 2b, is described above. The measurement was performed according to the method described in the embodiment. In the measurement, 15 electrode contact particles 2a and non-electrode contact particles 2b were used, respectively.

  In this example, in addition to the above evaluation, the DC bias characteristics 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.

DC bias characteristics DC bias characteristics were measured by calculating the change in relative permittivity (unit:%) when a DC voltage of 4 V / μm was applied to a capacitor sample at a constant temperature (25 ° C.). . In this example, the DC bias characteristic was an average value of values measured using 10 capacitor samples. The DC bias characteristics are preferably closer to 0, and in this example, the DC bias characteristics were −10% or more for all the samples, 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.

In the electrode paste, the BaTiO ₃ powder as a common material for the conductive powder 100 parts by weight, in sample No. 2-8 was added in an amount of 1 to 30 parts by weight, BaTiO ₃ in the electrode contact particles 2a the ratio _{a BT} of the number of crystal grains, the ratio _{B BT} of the number of BaTiO ₃ crystal grains in the non-electrode-contact particles 2b, _a BT _{-B BT} is the difference becomes a range of 5-40%. In these sample numbers 2 to 8, the relative permittivity and the capacitance temperature characteristic (especially the temperature characteristic on the low temperature side) are improved while maintaining the respective characteristics (DC bias characteristic, electrostriction amount when voltage is applied) well. It can be confirmed that this is possible.

In particular, by comparing sample numbers 2-4, by increasing the amount of BaTiO ₃ powder as a common _material, A BT _{-B BT} also gradually increased, the relative dielectric constant and the capacitance-temperature characteristic (especially at low temperatures It can be confirmed that the effect of improving the temperature characteristics on the side increases. Moreover, it can be confirmed from Sample Nos. 5 to 8 that similar results can be obtained even when the main component composition of the dielectric layer is changed.

In Sample Nos. 2 to 8, from the result of X-ray diffraction on the dielectric layer, there are three separated diffraction peaks in the range of 2θ = 30 to 35 °, and BaTiO ₃ , SrTiO ₃ , and It was also confirmed that CaTiO ₃ existed in a state where they were not substantially dissolved in each other.

On the other hand, in the sample number 1 in which the content of the BaTiO ₃ powder as the co-material is 0.5 parts by weight with respect to 100 parts by weight of the conductor powder, A _BT -B _BT is less than 5%, and the relative dielectric constant The result was a lower rate. In Sample No. 9 in which the content of the BaTiO ₃ powder as the co-material is 33 parts by weight with respect to 100 parts by weight of the conductor powder, A _BT -B _BT is too large as 40% or more, As a result, the electrode layer 3 was interrupted, the electrode coverage was reduced, and the capacitance was reduced, resulting in a lower dielectric constant.

FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention. FIG. 2 is a diagram for explaining the ratio of the number of BaTiO ₃ crystal particles in the electrode contact particles and the ratio of the number of BaTiO ₃ crystal particles in the non-electrode contact particles.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Multilayer ceramic capacitor 10 ... Capacitor element body 2 ... Dielectric layer 2a ... Electrode contact particle 2b ... Non-electrode contact particle 3 ... Internal electrode layer 4 ... External electrode

Claims (10)

A multilayer electronic component having a configuration in which dielectric layers and internal electrode layers are alternately stacked,
The dielectric layer contains BaTiO ₃ , SrTiO _3, and CaTiO ₃ as main components, and the BaTiO ₃ , SrTiO _3, and CaTiO ₃ are not substantially dissolved in each other, and a plurality of BaTiO ₃ Consists of a dielectric ceramic composition that is contained in the form of crystal particles, SrTiO ₃ crystal particles and CaTiO ₃ crystal particles and forms a composite structure,
The plurality of BaTiO ₃ crystal particles, SrTiO ₃ crystal particles, and CaTiO ₃ crystal particles constituting the dielectric layer are particles that are in direct contact with the internal electrode layer, and particles that are not in contact with the internal electrode layer. Consists of
When the particles that are in direct contact with the internal electrode layer are electrode contact particles, and the particles that are not in contact with the internal electrode layer are non-electrode contact particles,
A _BT [%] showing the percentage of the number of BaTiO ₃ crystal particles as a percentage of the total number of BaTiO ₃ crystal particles, SrTiO ₃ crystal particles and CaTiO ₃ crystal particles in the electrode contact particles,
Difference between B _BT [%], which is a percentage of the number of BaTiO ₃ crystal particles with respect to the total number of BaTiO ₃ crystal particles, SrTiO ₃ crystal particles, and CaTiO ₃ crystal particles in the non-electrode contact particles. (A _BT -B _BT ) is 5% or more. Wherein _{A BT} and the difference between _{B BT (A BT -B BT)} is laminated electronic component according to claim 1 or less 40%. _3. The multilayer electronic component according to claim 1, wherein an average crystal particle diameter of the plurality of BaTiO ₃ crystal particles, SrTiO ₃ crystal particles, and CaTiO ₃ crystal particles constituting the dielectric layer is 0.2 to 2 μm. .   The multilayer electronic component according to claim 1, wherein the dielectric layer has a thickness of 2 to 20 μm. Said BaTiO _3, SrTiO ₃ and CaTiO compositional molar ratio of ₃ contained as the main component in the dielectric ceramic composition, when indicated 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
0.19 ≦ x ≦ 0.23,
0.25 ≦ y ≦ 0.31,
0.46 ≦ z ≦ 0.54,
x + y + z = 1,
0.980 ≦ m ≦ 1.01,
The multilayer electronic component according to any one of claims 1 to 4. The dielectric ceramic composition further includes an oxide of Mn as a subcomponent,
The multilayer electronic component according to claim 1, wherein the content of the Mn oxide 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 multilayer electronic component according to claim 1, wherein a content of the Si oxide is 0.1 to 0.5 mol in terms of SiO _{2 with} respect to 100 mol of the main component. The dielectric ceramic composition further includes at least one selected from oxides of elements of V, Ta, Nb, W, Mo and Cr as subcomponents,
The oxide content of V, Ta, Nb, W, Mo and Cr is 0.02 mol in terms of each element of V, Ta, Nb, W, Mo and Cr with respect to 100 mol of the main component. The multilayer electronic component according to claim 1, wherein the content is less than 0.40 mol. A method of manufacturing a multilayer electronic component having a configuration in which dielectric layers and internal electrode layers are alternately laminated,
Forming a green sheet to be a dielectric layer after firing;
Using an electrode paste to form an electrode paste film that becomes an internal electrode layer after firing;
Alternately stacking the green sheet and the electrode paste film to obtain a green chip;
Firing the green chip,
The fired dielectric layer contains, as main components, BaTiO ₃ , SrTiO ₃ and CaTiO ₃ , and the BaTiO ₃ , SrTiO ₃ and CaTiO ₃ are not substantially dissolved in each other. A dielectric ceramic composition containing a BaTiO ₃ crystal particle, a SrTiO ₃ crystal particle, and a CaTiO ₃ crystal particle in the form of a composite structure,
A method of manufacturing a multilayer electronic component, wherein an electrode paste containing a conductor powder and a common material containing BaTiO ₃ powder is used as an electrode paste for forming the electrode paste film.   The method for producing a multilayer electronic component according to claim 9, wherein the content of the common material in the electrode paste is 1 to 30 parts by weight with respect to 100 parts by weight of the conductor powder.

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