JP7262640B2 - ceramic capacitor - Google Patents

Description

The present invention relates to ceramic capacitors.

Ceramic capacitors are increasingly being used in high-temperature environments, such as in vehicles. Accordingly, ceramic capacitors are required to have capacitance stability under high temperature and high reliability under high temperature load. In recent years, satisfying the EIA standard X7R characteristics (capacity change rate within ±15% in the range of −55° C. to 125° C. with reference to 25° C.) has become one of the important characteristics. Therefore, dielectrics that satisfy the X7R characteristics have been proposed by adjusting and designing the dielectric composition and microstructure (see, for example, Patent Document 1).

JP 2010-199268 A

However, with the technique of Patent Document 1, it is difficult to achieve both capacitance stability and high reliability.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a ceramic capacitor capable of achieving both capacitance stability and high reliability.

A ceramic capacitor according to the present invention includes a laminate in which dielectric layers and internal electrode layers are alternately laminated, and the dielectric layers are mainly composed of BaTiO ₃ and Ti as the main component is 100 atm %. 0.05 atm% or more and 0.35 atm% or less of Mn as the first subcomponent, 0.4 atm% or more and 0.8 atm% or less of Mg as the second subcomponent, and Ho and Dy as the third subcomponent. 0.5 atomic % or more and 0.9 atomic % or less of at least one rare earth element in total, 0.15 atomic % or more and 0.30 atomic % or less of V as a fourth subcomponent, and 0.15 atomic % or more of Si as a fifth subcomponent. 4 atm% or more and 0.9 atm% or less, Ca as a sixth subcomponent of 0.00 atm% or more and 0.45 atm% or less, and the average particle diameter of the ceramic particles constituting the dielectric layer is 280 nm or more and 380 nm or less. .

The size of the ceramic capacitor may be 0.2 mm long, 0.125 mm wide and 0.125 mm high. The size of the ceramic capacitor may be 0.4 mm long, 0.2 mm wide and 0.2 mm high. The size of the ceramic capacitor may be 3.2 mm long, 1.6 mm wide and 1.6 mm high. 0.10 atomic % or more and 0.30 atomic % or less of Mn may be included as the first subcomponent. 0.5 atomic % or more and 0.7 atomic % or less of Mg may be included as the second subcomponent. A rare earth element of 0.6 atomic % or more and 0.8 atomic % or less may be included as the third subcomponent. 0.18 atm % or more and 0.27 atm % or less of V may be included as the fourth subcomponent. 0.5 atomic % or more and 0.8 atomic % or less of Si may be included as the fifth subcomponent. 0.1 atomic % or more and 0.4 atomic % or less of Ca may be included as the sixth subcomponent. The BaTiO ₃ may be Ba _m TiO ₃ (0.9990≦m≦1.0015). The BaTiO ₃ may have an average particle size of 300 nm or more and 360 nm or less. The ceramic capacitor may include a cover layer containing the main component of the dielectric layer and the contents of the first to sixth subcomponents in the stacking direction of the laminate. The ceramic capacitor may satisfy EIA standard X7R characteristics.

According to the present invention, it is possible to provide a ceramic capacitor capable of achieving both capacitance stability and high reliability.

1 is a partial cross-sectional perspective view of a laminated ceramic capacitor; FIG. It is a figure which illustrates the flow of the manufacturing method of a laminated ceramic capacitor. FIG. 4 is a diagram showing the amounts of the first to sixth subcomponents added in Examples and Comparative Examples. FIG. 4 is a diagram showing the results of each measurement test for Examples and Comparative Examples;

Hereinafter, embodiments will be described with reference to the drawings.

(embodiment)
FIG. 1 is a partial cross-sectional perspective view of a laminated ceramic capacitor 100 according to an embodiment. As illustrated in FIG. 1, a multilayer ceramic capacitor 100 includes a ceramic body 10 having a substantially rectangular parallelepiped shape, and external electrodes 20a and 20b provided on two opposing end faces of the ceramic body 10. As shown in FIG. Of the four surfaces of the ceramic body 10 other than the two end surfaces, two surfaces other than the upper surface and the lower surface in the stacking direction are referred to as side surfaces. The external electrodes 20a and 20b extend on the upper surface, lower surface and two side surfaces of the ceramic body 10 in the stacking direction. However, the external electrodes 20a and 20b are separated from each other.

The ceramic body 10 has a structure in which dielectric layers 11 containing a ceramic material functioning as a dielectric and internal electrode layers 12 functioning as conductor layers are alternately laminated. Edges of the internal electrode layers 12 are alternately exposed to the end surface of the ceramic body 10 provided with the external electrodes 20a and the end surface of the ceramic body 10 provided with the external electrodes 20b. Thereby, each internal electrode layer 12 is alternately connected to the external electrode 20a and the external electrode 20b. As a result, the multilayer ceramic capacitor 100 has a configuration in which a plurality of dielectric layers 11 are laminated with internal electrode layers 12 interposed therebetween. In the laminated structure of the dielectric layers 11 and the internal electrode layers 12 , the internal electrode layer 12 is arranged as the outermost layer in the lamination direction, and the top and bottom surfaces of the laminate are covered with the cover layer 13 . The cover layer 13 is mainly composed of a ceramic material. For example, the material of the cover layer 13 is the same as the main component of the dielectric layer 11 and the ceramic material.

The size of the multilayer ceramic capacitor 100 is, for example, length 0.2 mm, width 0.125 mm, and height 0.125 mm, or length 0.4 mm, width 0.2 mm, height 0.2 mm, or length 0.6 mm, 0.3 mm wide and 0.3 mm high; or 1.0 mm long, 0.5 mm wide and 0.5 mm high; or 3.2 mm long, 1.6 mm wide and 0.5 mm high. 1.6 mm in height, or 4.5 mm in length, 3.2 mm in width and 2.5 mm in height, but are not limited to these sizes.

The internal electrode layers 12 are mainly composed of base metals such as Ni (nickel), Cu (copper), and Sn (tin). As the internal electrode layers 12, noble metals such as Pt (platinum), Pd (palladium), Ag (silver), Au (gold), and alloys containing these may be used. The dielectric layer 11 and the cover layer 13 are mainly composed of a ceramic having a perovskite structure represented by the general formula _ABO3 . Note that the perovskite structure contains ABO _3-α deviating from the stoichiometric composition. The perovskite is barium titanate containing _Ba (barium) and Ti (titanium), represented by _BamTiO3 . Since barium titanate is a ferroelectric, a high dielectric constant is achieved.

In the multilayer ceramic capacitor 100 according to the present embodiment, the dielectric layers 11 contain subcomponents to achieve both capacitance stability and high reliability. Details of the subcomponents added to the dielectric layer 11 will be described below.

Dielectric layer 11 contains Mn (manganese) as a first subcomponent. Mn has the effect of realizing good sinterability and improving the life characteristics of the multilayer ceramic capacitor 100 . Thereby, high reliability of the multilayer ceramic capacitor 100 can be realized. However, if Mn is too small, there is a possibility that high reliability cannot be achieved. On the other hand, if the Mn content is too high, the grain boundary resistance of the ceramic grains is lowered, so that the insulating properties may be lowered and the reliability may be lowered. Therefore, upper and lower limits are set for the Mn concentration in the dielectric layer 11 . Specifically, the dielectric layer 11 contains 0.05 atm % or more and 0.35 atm % or less of Mn when Ti in _{BamTiO 3} , which is the main component ceramic of the dielectric layer 11, is 100 atm %. there is Note that the dielectric layer 11 may contain 0.10 atm % or more and 0.30 atm % or less of Mn when Ti in _{BamTiO 3} , which is the main component ceramic of the dielectric layer 11, is 100 atm %. preferable.

Next, dielectric layer 11 contains Mg (magnesium) as a second subcomponent. Mg has the effect of controlling grain growth during firing, and realizes capacity stability and high reliability. However, if the Mg content is too low, there is a possibility that sufficient capacity stability cannot be achieved. In addition, grain growth occurs during the sintering process, which may reduce reliability. On the other hand, if there is too much Mg, there is a possibility that the reliability may be lowered due to reasons such as an excess of acceptors. Therefore, an upper limit and a lower limit are set for the Mg concentration in the dielectric layer 11 . Specifically, the dielectric layer 11 contains 0.4 atm % or more and 0.8 atm % or less of Mg when Ti in _{BamTiO 3} , which is the main component ceramic of the dielectric layer 11, is 100 atm %. . The dielectric layer 11 preferably contains 0.5 atm % or more and 0.7 atm % or less of Mg when Ti in _{BamTiO 3} , which is the main component ceramic of the dielectric layer 11, is 100 atm %. .

Next, the dielectric layer 11 contains at least one rare earth element Re of Ho (holmium) and Dy (dysprosium) as a third subcomponent. The rare earth element Re has the effect of adjusting the balance of the solid solution sites (A site and B site) of the additive element, and achieves high reliability. However, if the rare earth element Re is too small, sufficient reliability may not be obtained. On the other hand, if the rare earth element Re is too much, the sinterability of the dielectric layer 11 deteriorates due to the fact that the sintering temperature of the ceramic becomes high, and sufficient reliability may not be obtained. Therefore, an upper limit and a lower limit are set for the rare earth element Re concentration in the dielectric layer 11 . Hereinafter, the concentration of the rare earth element Re means the total concentration of Ho and Dy. Specifically, the dielectric layer 11 contains 0.5 atm % or more and 0.9 atm % or less of the rare earth element Re when Ti in _{BamTiO 3} , which is the main component ceramic of the dielectric layer 11, is 100 atm %. I'm in. Note that the dielectric layer 11 contains 0.6 atm % or more and 0.8 atm % or less of the rare earth element Re when Ti in _{BamTiO 3} , which is the main component ceramic of the dielectric layer 11, is 100 atm %. is preferred.

Next, dielectric layer 11 contains V (vanadium) as a fourth subcomponent. V has the effects of suppressing the generation of oxygen defects and controlling the fine structure of the ceramic, thereby realizing high reliability and capacity stability. However, if V is too small, there is a possibility that sufficient high reliability and sufficient capacity stability cannot be obtained. On the other hand, if V is too high, sufficient capacitance stability may not be obtained because the electrical resistance decreases or the target ceramic microstructure cannot be produced. Therefore, upper and lower limits are set for the V concentration in the dielectric layer 11 . Specifically, the dielectric layer 11 contains 0.15 atm % or more and 0.30 atm % or less of V when Ti in _{BamTiO 3} which is the main component ceramic of the dielectric layer 11 is 100 atm %. . The dielectric layer 11 preferably contains 0.18 atm % or more and 0.27 atm % or less of V when Ti in _{BamTiO 3} , which is the main component ceramic of the dielectric layer 11, is 100 atm %. .

Next, dielectric layer 11 contains Si (silicon) as a fifth subcomponent. Since Si functions as a sintering aid, good sintering is achieved. However, if the amount of Si is too small, sintering at an appropriate temperature (for example, 1260° C. or less) becomes difficult, and the dielectric layer 11 may not be obtained. On the other hand, if the amount of Si is too large, grain growth may occur during the sintering process due to excessive generation of liquid phase components, and sufficient capacity stability may not be obtained. Therefore, an upper limit and a lower limit are set for the Si concentration in the dielectric layer 11 . Specifically, the dielectric layer 11 contains 0.4 atm % or more and 0.9 atm % or less of Si when Ti in _{BamTiO 3} which is the main component ceramic of the dielectric layer 11 is 100 atm %. . The dielectric layer 11 preferably contains 0.5 atm % or more and 0.8 atm % or less of Si when Ti in _{BamTiO 3} , which is the main component ceramic of the dielectric layer 11, is 100 atm %. .

Next, dielectric layer 11 contains Ca (calcium) as a sixth subcomponent. Ca functions as a sintering aid and can be used to adjust the A/B ratio, which is the molar ratio between the A-site element and the B-site element. However, if there is too much Ca, there is a possibility that sufficient capacity stability cannot be obtained due to the reason that the A site component is excessive. Therefore, an upper limit is set for the Ca concentration in the dielectric layer 11 . Specifically, the dielectric layer 11 contains 0.00 _atm % or more and 0.45 atm% or less of Ca when Ti in _BamTiO3 , which is the main component ceramic of the dielectric layer 11, is 100 atm%. . "0.00 atm% or more of Ca" means that Ca may not be included. Note that the dielectric layer 11 preferably contains 0.10 atm % or more and 0.40 atm % or less of Ca when Ti in _{BamTiO 3} , which is the main component ceramic of the dielectric layer 11, is 100 atm %. .

Next, if the m of _BamTiO3 , which is the main component ceramic of the dielectric layer 11, is too low, the life characteristics _of the multilayer ceramic capacitor 100 may deteriorate, and high reliability may not be obtained. Therefore, m takes a value of 0.9990≦m. On the other hand, if m is too high, it may not be possible to obtain capacity stability. Therefore, m takes a value of m≦1.0015.

Next, if the average particle size of _BamTiO3 , which is the main component ceramic of the dielectric layer ₁₁ , is too small, the capacitance stability may decrease because the target ceramic microstructure cannot be obtained. . On the other hand, if the average particle size is too large, the number of grain boundaries in the ceramic is reduced, which may lead to problems such as reduced insulation resistance and reduced reliability. Therefore, an upper limit and a lower limit are set for _the average particle size of _BamTiO3 . Specifically, the average particle size of _{BamTiO 3} is set to 280 nm or more and 380 nm or less. The average particle size of _{BamTiO 3} is preferably 300 nm or more and 360 nm or less.

The average particle size can be calculated by arithmetic mean as follows. For example, SEM observation is performed in a field of view in which about 100 to 200 crystal grains can be confirmed. For example, assume that the magnification is 40,000 times. In the obtained SEM image, particles that can be visually confirmed as particles are aligned in one direction and measured. For example, the horizontal direction of the SEM image is unified in the horizontal direction. The average value is calculated by dividing the total measured value by the number of measured particles. The direction of the image and the direction of length measurement can be arbitrary.

By defining the contents of the first subcomponent to the sixth subcomponent in the dielectric layer 11 as described above, defining the value of m of _{BamTiO 3} , and defining the average particle size of _{BamTiO 3 ,} , it is possible to achieve both capacity stability and high reliability. The material of the cover layer 13 is the same as the main component of the dielectric layer 11 and the ceramic material. is defined, the value of m of _BamTiO3 is defined, _{and the} average particle size of _BamTiO3 is defined.

Next, a method for manufacturing the laminated ceramic capacitor 100 will be described. FIG. 2 is a diagram illustrating the flow of the manufacturing method of the multilayer ceramic capacitor 100. As shown in FIG.

(Raw material powder preparation process)
First, a dielectric material for forming the dielectric layer 11 is prepared. The A-site and B-site elements contained in the dielectric layer 11 are usually contained in the dielectric layer 11 in the form of sintered particles of _ABO3 . For example, barium titanate is a tetragonal compound having a perovskite structure and exhibits a high dielectric constant. This BaTiO ₃ can generally be obtained by reacting a titanium raw material such as titanium dioxide with a barium raw material such as barium carbonate to synthesize barium titanate. In addition, the titanium raw material and the barium raw material are reacted so that m takes a value of 0.9990≦m≦1.0015 in the general formula A _m BO ₃ representing the perovskite structure of the barium titanate. Various methods are conventionally known for synthesizing the ceramic constituting the dielectric layer 11, such as a solid-phase synthesis method, a sol-gel synthesis method, a hydrothermal synthesis method, and the like.

A predetermined additive compound is added to the obtained ceramic powder according to the purpose. Additive compounds include Mg, Mn, V, Cr (chromium), rare earth elements (Y (yttrium), Sm (samarium), Eu (europium), Gd (gadolinium), Tb (terbium), Dy, Ho, Er( erbium), Tm (thulium) and Yb (ytterbium)), and oxides of Co (cobalt), Ni, Li (lithium), B (boron), Na (sodium), K (potassium) and Si Alternatively, glass may be used.

In the present embodiment, when Ti in _{BamTiO 3} , which is the main component ceramic of the ceramic powder, is 100 atm%, 0.05 atm% or more and 0.35 atm% or less of Mn is added as the first subcomponent, and the second 0.4 atomic % or more and 0.8 atomic % or less of Mg is added as an auxiliary component, and 0.5 atomic % or more and 0.9 atomic % or less of a rare earth element Re of at least one of Ho and Dy is added as a third auxiliary component, 0.15 atm% or more and 0.30 atm% or less of V is added as the fourth subcomponent, 0.4 atm% or more and 0.9 atm% or less of Si is added as the fifth subcomponent, and 0.00 atm% of Ca is added as the sixth subcomponent. Add more than 0.45 atm % or less.

In this embodiment, preferably, barium titanate particles are first mixed with a compound containing an additive compound and calcined at 820 to 1150°C. The resulting ceramic particles are then wet mixed with additive compounds, dried and ground to prepare a ceramic powder. For example, the average particle size of the ceramic powder is preferably 200 nm to 300 nm from the viewpoint of thinning the dielectric layer 11 . For example, the ceramic powder obtained as described above may be pulverized to adjust the particle size, or combined with a classification process to adjust the particle size.

(Lamination process)
Next, a binder such as polyvinyl butyral (PVB) resin, an organic solvent such as ethanol or toluene, and a plasticizer are added to the obtained dielectric material and wet-mixed. Using the obtained slurry, a green sheet having a thickness of, for example, 3 μm to 10 μm is molded by, for example, a die coater method or a doctor blade method.

Next, a metal conductive paste for forming internal electrodes containing an organic binder is printed on the surface of the green sheet by screen printing, gravure printing, or the like, thereby forming an internal electrode layer pattern that is alternately led to a pair of external electrodes having different polarities. are placed to form a patterned sheet. Ceramic particles are added to the metal conductive paste as a common material. Although the main component of the ceramic particles is not particularly limited, it is preferably the same as the main component ceramic of the dielectric layer 11 . For example, BaTiO ₃ having an average particle size of 50 nm or less may be uniformly dispersed.

Next, a plurality of green sheets are laminated to form a cover sheet, a plurality of pattern forming sheets are laminated on the cover sheet, and a plurality of green sheets are laminated on the obtained laminate. to form a cover sheet. The obtained laminate is cut into a predetermined size.

(Baking process)
The molded body thus obtained is subjected to binder removal treatment in an N ₂ atmosphere at 250 to 500° C., and then in a reducing atmosphere with an oxygen partial pressure of 10 ⁻⁵ to 10 ⁻⁸ atm at 1100 to 1300° C. for 10 minutes. By firing for ~2 hours, each compound is sintered and grains grow. Thus, the ceramic body 10 is obtained. _The firing conditions may be adjusted to other conditions so that the average particle size of _BamTiO3 , which is the main component ceramic of the dielectric layer 11 after firing, is 280 nm or more and 380 nm or less.

(Reoxidation treatment step)
After that, reoxidation treatment may be performed at 600° C. to 1000° C. in an N ₂ gas atmosphere.

(External electrode forming step)
Next, a conductive paste for forming the external electrodes 20a and 20b is applied to the two end surfaces of the obtained sintered body where the internal electrode layer patterns are exposed. Cu or the like can be used for the conductive paste. It is fired in a nitrogen atmosphere at a temperature lower than the firing temperature for obtaining the sintered body (for example, about 800° C. to 900° C.). Thereby, the external electrodes 20a and 20b are baked. After that, metal coating such as Cu, Ni, and Sn may be applied by plating. The conductive paste for forming the external electrodes 20a and 20b may be applied to the two end surfaces of the laminate of green sheets before the firing process described above, and the laminate and the conductive paste may be fired simultaneously in the firing process.

In the present embodiment, when Ti of the perovskite structure is 100 atm% _in a ceramic powder having a perovskite structure represented by _BamTiO3 (0.9990≦m≦1.0015), the first 0.05 atomic % or more and 0.35 atomic % or less of Mn is added as an accessory component. 0.4 atomic % or more and 0.8 atomic % or less of Mg is added as a second subcomponent. As a third subcomponent, at least one rare earth element of Ho and Dy is added in an amount of 0.5 atm % or more and 0.9 atm % or less. 0.15 atomic % or more and 0.30 atomic % or less of V is added as a fourth subcomponent. 0.4 atomic % or more and 0.9 atomic % or less of Si is added as a fifth subcomponent. 0.00 atomic % or more and 0.45 atomic % or less of Ca is added as a sixth subcomponent. In addition, the conditions of the firing process are adjusted so that the average particle size of _{BamTiO 3} in the dielectric layer 11 after firing is 280 nm or more and 380 nm or less. Thereby, in the multilayer ceramic capacitor 100, both capacitance stability and high reliability can be achieved.

Although the above embodiment has been described with a focus on the laminated ceramic capacitor, the above embodiment can also be applied to a ceramic capacitor having a single dielectric layer.

Hereinafter, multilayer ceramic capacitors according to the embodiments were produced and their characteristics were examined.

_Bam TiO ₃ powder was prepared as the main component ceramic of the dielectric layer 11 and the cover layer 13 . MnCO ₃ was prepared as the first subcomponent. MgO was prepared as the second subcomponent. Dy ₂ O ₃ and Ho ₂ O ₃ were prepared as the third subcomponent. V ₂ O ₅ was prepared as the fourth subcomponent. SiO ₂ was prepared as the fifth subcomponent. CaCO ₃ was prepared as the sixth subcomponent.

The powder of barium titanate and the first to sixth subcomponents were weighed so as to have a predetermined ratio, and sufficiently wet-mixed and pulverized in a ball mill to obtain a dielectric material. A butyral-based organic binder, toluene and ethyl alcohol as solvents were added to the dielectric material, and zirconia beads were used as dispersion media to obtain a slurry. In this case, the amount of zirconia beads used was set to 0.20 atm % or more and 0.26 atm % or less of Zr when Ti in _{BamTiO 3} was 100 atm %.

(Example 1)
In Example 1, when Ti in _{the BamTiO3} powder was 100 atm %, MnCO ₃ was added as the first subcomponent so that Mn was 0.05 atm %, and Mg was added as the second subcomponent to 0.05 atm %. MgO is added to 60 atm%, Ho is added to 0.68 atm% as the third subcomponent, and V is added to 0.25 atm% as the _{fourth subcomponent} . _2O5 is added, _SiO2 is added as the fifth subcomponent so that Si becomes 0.50 atm _% , _CaCO3 is added as the sixth subcomponent so that Ca becomes 0.15 atm%, and m was set to 0.9997.

(Example 2)
Example 2 was the same as Example 1 except that MnCO ₃ was added as the first subcomponent so that the Mn content was 0.15 atm %.

(Example 3)
Example 3 was the same as Example 1 except that MnCO ₃ was added as the first subcomponent so that the Mn content was 0.35 atm %.

(Comparative example 1)
Comparative Example 1 was the same as Example 1 except that the first subcomponent was not added and the value of m was set to 0.9996.

(Comparative example 2)
Comparative Example 2 was the same as Example 1, except that MnCO ₃ was added as the first subcomponent so that the Mn content was 0.45 atm %, and the value of m was set to 0.9996.

(Example 4)
In Example 4, when Ti in _{the BamTiO3} powder was 100 atm %, MnCO ₃ was added as the first subcomponent so that Mn was 0.15 atm %, and Mg was added as the second subcomponent to 0.15 atm %. MgO is added to 40 atm %, Ho is added to 0.68 atm % as the third subcomponent, and V is added to 0.25 atm % as the _{fourth subcomponent} . _2O5 is added, _SiO2 is added as the _fifth subcomponent so that Si becomes 0.50 atm%, _CaCO3 is added as the sixth subcomponent so that Ca becomes 0.15 atm%, and m was set to 0.9996.

(Example 5)
Example 5 was the same as Example 4, except that MgO was added as the second subcomponent so that the Mg content was 0.60 atm %, and the value of m was set to 0.9997.

(Example 6)
Example 6 was the same as Example 4, except that MgO was added as the second subcomponent so that the Mg content was 0.80 atm %, and the value of m was set to 0.9993.

(Comparative Example 3)
Comparative Example 3 was the same as Example 4, except that MgO was added as the second subcomponent so that the Mg content was 0.20 atm %, and the value of m was set to 0.9995.

(Comparative Example 4)
Comparative Example 4 was the same as Example 4, except that MgO was added as the second subcomponent so that the Mg content was 1.0 atm %, and the value of m was set to 0.9998.

(Example 7)
In Example 7, when Ti in _{the BamTiO3} powder was 100 atm %, MnCO ₃ was added as the first subcomponent so that Mn was 0.15 atm %, and Mg was added as the second subcomponent to 0.15 atm %. MgO is added to 60 atm%, Ho is added to 0.50 atm% as the third subcomponent, and V is added to 0.25 atm% as the _{fourth subcomponent} . _2O5 is added, _SiO2 is added as the fifth subcomponent so that Si becomes 0.50 atm _% , _CaCO3 is added as the sixth subcomponent so that Ca becomes 0.15 atm%, and m was set to 0.9999.

(Example 8)
Example 8 was the same as Example 7, except that Ho ₂ O ₃ was added as the third subcomponent so that Ho was 0.70 atm %, and the value of m was set to 0.9997.

(Example 9)
Example 9 was the same as Example 7, except that Ho ₂ O ₃ was added as the third subcomponent so that Ho was 0.90 atm %, and the value of m was set to 0.9998.

(Comparative Example 5)
Comparative Example 5 was the same as Example 7, except that Ho ₂ O ₃ was added as the third subcomponent so that Ho was 0.20 atm %, and the value of m was set to 0.9996.

(Comparative Example 6)
Comparative Example 6 was the same as Example 7, except that Ho ₂ O ₃ was added as the third subcomponent so that Ho became 1.10 atm %, and the value of m was set to 0.9996.

(Example 10)
In Example 10, when Ti in _{the BamTiO3} powder was 100 atm %, MnCO ₃ was added as the first subcomponent so that Mn was 0.15 atm %, and Mg was added as the second subcomponent to 0.15 atm %. MgO is added to 60 atm %, Ho is added to 0.68 atm % as the third subcomponent, and V is added to 0.15 atm % as the _{fourth subcomponent} . _2O5 is added, _SiO2 is added as the fifth subcomponent so that Si becomes 0.60 atm _% , _CaCO3 is added as the sixth subcomponent so that Ca becomes 0.15 atm%, and m was set to 1.0001.

(Example 11)
Example 11 was the same as Example 10 except that V ₂ O ₅ was added as the fourth subcomponent so that V was 0.25 atm % and the value of m was set to 1.0002.

(Example 12)
Example 12 was the same as Example 10 except that V ₂ O ₅ was added as the fourth subcomponent so that V was 0.30 atm % and the value of m was set to 1.0002.

(Comparative Example 7)
Comparative Example 7 was the same as Example 10 except that the fourth subcomponent was not added and the value of m was set to 1.0002.

(Comparative Example 8)
Comparative Example 8 was the same as Example 10, except that V ₂ O ₅ was added as the fourth subcomponent so that V was 0.35 atm %, and the value of m was set to 0.9998.

(Example 13)
In Example 13, when Ti in _{the BamTiO3} powder was 100 atm %, MnCO ₃ was added as the first subcomponent so that Mn was 0.15 atm %, and Mg was added as the second subcomponent to 0.15 atm %. MgO is added to 60 atm%, Ho is added to 0.68 atm% as the third subcomponent, and V is added to 0.25 atm% as the _{fourth subcomponent} . _2O5 is added, _SiO2 is added as the fifth subcomponent so that Si becomes 0.40 atm _% , _CaCO3 is added as the sixth subcomponent so that Ca becomes 0.15 atm%, and m was set to 0.9998.

(Example 14)
Example 14 was the same as Example 13, except that SiO ₂ was added as the fifth subcomponent so that the Si content was 0.60 atm %, and the value of m was set to 0.9995.

(Example 15)
Example 15 was the same as Example 13, except that SiO ₂ was added as the fifth subcomponent so that the Si content was 0.90 atm %, and the value of m was set to 1.0000.

(Comparative Example 9)
Comparative Example 9 was the same as Example 13, except that SiO ₂ was added as the fifth subcomponent so that the Si content was 0.30 atm %, and the value of m was set to 1.0000.

(Comparative Example 10)
Comparative Example 10 was the same as Example 13, except that SiO ₂ was added as the fifth subcomponent so that the Si content was 1.00 atm %, and the value of m was set to 0.9996.

(Example 16)
In Example 16, when Ti in _{the BamTiO3} powder was 100 atm %, MnCO ₃ was added as the first subcomponent so that Mn was 0.15 atm %, and Mg was added as the second subcomponent to 0.15 atm %. MgO is added to 60 atm%, Ho is added to 0.68 atm% as the third subcomponent, and V is added to 0.25 atm% as the _{fourth subcomponent} . ₂ O ₅ was added, SiO ₂ was added as the fifth subcomponent so that Si content was 0.50 atm %, and the value of m was set to 1.0002 without adding the sixth subcomponent.

(Example 17)
Example 17 was the same as Example 16 except that CaO was added as the sixth subcomponent so that Ca content was 0.25 atm %.

(Example 18)
Example 18 was the same as Example 16, except that Ca was added as the sixth subcomponent so that Ca content was 0.45 atm %.

(Comparative Example 11)
Comparative Example 11 was the same as Example 16 except that CaO was added as the sixth subcomponent so that Ca content was 0.55 atm %.

(Example 19)
In Example 19, when Ti in _{the BamTiO3} powder was 100 atm %, MnCO ₃ was added as the first subcomponent so that Mn was 0.15 atm %, and Mg was added as the second subcomponent to 0.15 atm %. MgO is added to 60 atm%, Ho is added to 0.68 atm% as the third subcomponent, and V is added to 0.25 atm% as the _{fourth subcomponent} . _2O5 is added, _SiO2 is added as the fifth subcomponent so that Si becomes 0.50 atm _% , _CaCO3 is added as the sixth subcomponent so that Ca becomes 0.15 atm%, and m was set to 0.9990.

(Example 20)
Example 20 was the same as Example 19, except that the value of m was 1.0002.

(Example 21)
Example 21 was the same as Example 19, except that the value of m was 1.0015.

(Comparative Example 12)
Comparative Example 12 was the same as Example 19, except that the value of m was set to 0.9985.

(Comparative Example 13)
Comparative Example 13 was the same as Example 19, except that the value of m was set to 1.0020.

(Example 22)
In Example 22, when Ti in _{the BamTiO3} powder was 100 atm %, MnCO ₃ was added as the first subcomponent so that Mn was 0.15 atm %, and Mg was added as the second subcomponent to 0.15 atm %. MgO is added to 60 atm %, Dy ₂ O ₃ is added as a third subcomponent so that Dy is 0.68 atm %, and V is added as a fourth subcomponent so that V is 0.25 atm %. _2O5 is added, _SiO2 is added as the fifth subcomponent so that Si becomes 0.50 atm _% , _CaCO3 is added as the sixth subcomponent so that Ca becomes 0.15 atm%, and m was set to 0.9997.

(Comparative Example 14)
In Comparative Example 14, when Ti in the _{BamTiO 3} powder was 100 atm %, MnCO ₃ was added as the first subcomponent so that Mn was 0.12 atm %, and Mg was added as the second subcomponent to 0.12 atm %. MgO is added to 80 atm%, Ho is added to 1.30 atm% as the third subcomponent, and V is added to 0.18 atm% as the _{fourth subcomponent} . _2O5 is added, _SiO2 is added as the fifth subcomponent so that Si becomes 0.90 atm _% , _CaCO3 is added as the sixth subcomponent so that Ca becomes 0.20atm%, and m was set to 1.0002.

FIG. 3 shows the addition amounts of the first to sixth subcomponents and the value of m in Examples 1 to 22 and Comparative Examples 1 to 14. In addition, blanks in FIG. 3 mean that they were not intentionally added.

Next, the slurries obtained in Examples 1 to 22 and Comparative Examples 1 to 14 were formed into green sheets having a thickness of 7 μm by a doctor blade method or the like. Next, an internal electrode forming paste containing Ni as a main component was printed on the green sheet to prepare a pattern forming sheet. After that, 10 pattern forming sheets were laminated on a cover sheet (laminate of 50 green sheets), and further a cover sheet (laminate of 50 green sheets) was laminated. After that, pressure bonding was performed at 100°C to 120°C.

After cutting the obtained laminate into a predetermined size, it was degreased in an _N2 atmosphere. After that, sintering was performed in a reducing atmosphere at 1230° C. for 2 hours. In the process of lowering the temperature of firing, the partial pressure of oxygen was increased to perform re-oxidation treatment. A ceramic body 10 was thereby obtained. After that, a glass frit-containing Cu external electrode paste was applied to the two end surfaces of the ceramic body 10 and baked in an _N2 atmosphere to obtain a laminated ceramic capacitor 100 of 3.2 mm x 1.6 mm x 0.6 mm. The thickness of the dielectric layer 11 was 5 μm.

The average particle size of the ceramic particles in the dielectric layer 11 after firing was 330 nm in Example 1, 327 nm in Example 2, 335 nm in Example 3, and 345 nm in Example 4. 5, 337 nm in Example 6, 331 nm in Example 7, 320 nm in Example 8, 323 nm in Example 9, 313 nm in Example 10, and 313 nm in Example 11. 311 nm in Example 12, 308 nm in Example 13, 343 nm in Example 14, 330 nm in Example 15, 320 nm in Example 16, and 306 nm in Example 17. , Example 18 was 314 nm, Example 19 was 340 nm, Example 20 was 311 nm, Example 21 was 307 nm, and Example 22 was 330 nm. It is 329 nm in Comparative Example 1, 331 nm in Comparative Example 2, 1000 nm or more in Comparative Example 3, 335 nm in Comparative Example 4, 343 nm in Comparative Example 5, and 317 nm in Comparative Example 6. 307 nm in Example 7, 319 nm in Comparative Example 8, 403 nm in Comparative Example 10, 310 nm in Comparative Example 11, 385 nm in Comparative Example 12, 302 nm in Comparative Example 13, and 302 nm in Comparative Example 14. was 198 nm.

(analysis)
Each measurement test was performed on each of the multilayer ceramic capacitors 100 obtained in Examples 1-22 and Comparative Examples 1-14.

(Relative permittivity ε _r , Tan δ test)
A heat recovery treatment was performed at 150° C. for 1 hour, and after 24 hours, the capacity and Tan δ of the laminated ceramic capacitor 100 were measured with an LCR meter. The measurement conditions were 1 kHz-1 Vrms. From the capacitance C, the dielectric constant εr of the dielectric layer 11 was obtained according to the following formula (1) using the effective intersection area S, the number of layers n, the thickness t of the dielectric layer 11, and the vacuum dielectric _{constant ε0} . . The effective intersection area is the sum of the areas where adjacent internal electrode layers 12 face each other in the capacitance region where adjacent internal electrode layers 12 connected to different external electrodes face each other.
ε _r =(C×t)/(ε ₀ ×S×n) (1)

(Temperature characteristic test)
Next, the MAX temperature at which the capacity C becomes maximum was measured. Also, the ratio of the capacity C at MAX temperature to the capacity C at 125° C. (MAX/125° C.) was measured. If the MAX temperature is in the range of 35° C. or higher and 125° C. or lower, and the ratio (MAX/125° C.) is in the range of 0.8 to 1, X7R will be accepted as “○”, and other than that will be rejected as “×”. Judged.

(lifetime test)
For MTTF, the time required for the resistance value to decrease by three orders of magnitude from the insulation resistance value before the test was measured when a voltage (electric field) of 30 V/μm was applied at 150°C.

FIG. 4 shows the results of each measurement test for Examples 1-22 and Comparative Examples 1-14. In Comparative Example 1, the MTTF was as short as 1 hour, and sufficient reliability was not obtained. It is believed that this is because the first subcomponent was not added. Next, in Comparative Example 2, MTTF was as short as 12 hours, and sufficient reliability was not obtained. It is believed that this is because the added amount of the first subcomponent exceeded 0.35 atm %.

In Comparative Example 3, grain growth occurred and reliability decreased. Moreover, sufficient capacity stability was not obtained. It is considered that this is because the added amount of the second subcomponent was less than 0.40 atm %. In Comparative Example 4, the MTTF was as short as 14 hours, and sufficient reliability was not obtained. It is believed that this is because the added amount of the second subcomponent exceeded 0.8 atm %.

In Comparative Example 5, the MTTF was as short as 18 hours, and sufficient reliability was not obtained. It is believed that this is because the added amount of the third subcomponent was less than 0.5 atm %. In Comparative Example 6, sinterability deteriorated and sufficient reliability was not obtained. It is believed that this is because the added amount of the third subcomponent exceeded 0.9 atm %.

In Comparative Example 7, the MTTF was as short as 5 hours, and sufficient reliability was not obtained. Moreover, sufficient capacity stability was not obtained. It is believed that this is because the fourth subcomponent was not added. In Comparative Example 8, sufficient capacity stability was not obtained. It is considered that this is because the added amount of the fourth subcomponent exceeded 0.30 atm %.

In Comparative Example 9, the dielectric layer 11 could not be fired. It is believed that this is because the added amount of the fifth subcomponent was less than 0.4 atm %. In Comparative Example 10, grain growth occurred and sufficient capacity stability was not obtained. This is probably because the added amount of the fifth subcomponent exceeded 0.9 atm %.

In Comparative Example 11, sufficient capacity stability was not obtained. It is considered that this is because the added amount of the sixth subcomponent exceeded 0.45 atm %.

In Comparative Example 12, grain growth occurred and sufficient capacity stability was not obtained. It is believed that this is because m of _BamTiO3 was less than _0.9990 . In Comparative Example 13, sufficient capacity stability was not obtained. It is believed that this is because m exceeded 1.0015.

In Comparative Example 14, sufficient capacity stability was not obtained. It is believed that this is because the grain size in the dielectric layer 11 was less than 280 nm.

In contrast, Examples 1-22 had longer MTTFs and passed the X7R test. That is, it was possible to achieve both high reliability and capacity stability. This is because when 100 atm% of Ti having a perovskite structure is contained in a ceramic powder having a perovskite structure represented by _BamTiO3 ( _{0.9990≤m≤1.0015} ), 0.05 atm% or more and 0.35 atm% or less of Mn is added, 0.4 atm% or more and 0.8 atm% or less of Mg is added as a second subcomponent, and at least one of Ho and Dy is a rare earth element as a third subcomponent. 0.5 atm % or more and 0.9 atm % or less of element Re is added, 0.15 atm % or more and 0.30 atm % or less of V is added as a fourth subcomponent, and 0.4 atm % or more and 0.4 atm % or more of Si is added as a fifth subcomponent. 9 atm% or less was added, and 0.00 atm% or more and 0.45 atm% or less of Ca was added as the sixth subcomponent, and the average particle diameter of _{BamTiO 3} in the dielectric layer 11 after firing was 280 nm or more and 380 nm or less. It is considered to be

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations can be made within the scope of the gist of the present invention described in the scope of claims. Change is possible.

REFERENCE SIGNS LIST 10 ceramic body 11 dielectric layer 12 internal electrode layer 13 cover layer 20a, 20b external electrode 100 laminated ceramic capacitor

Claims (14)

A laminated body in which dielectric layers and internal electrode layers are alternately laminated,
The dielectric layer contains BaTiO ₃ as a main component, contains 0.05 atm % or more and 0.35 atm % or less of Mn as a first subcomponent when Ti of the main component is 100 atm %, and contains 0.4 atm% or more and 0.8 atm% or less of Mg, a total of 0.5 atm% or more and 0.9 atm% or less of at least one rare earth element of Ho and Dy as a third subcomponent, and a fourth subcomponent of Contains 0.15 atm% or more and 0.30 atm% or less of V, contains 0.4 atm% or more and 0.9 atm% or less of Si as a fifth subcomponent, and contains 0.00 atm% or more and 0.45 atm% or less of Ca as a sixth subcomponent. including
A ceramic capacitor, wherein an average particle diameter of ceramic particles constituting the dielectric layer is 280 nm or more and 380 nm or less. 2. The ceramic capacitor of claim 1, wherein the size of the ceramic capacitor is 0.2 mm long, 0.125 mm wide and 0.125 mm high. 2. The ceramic capacitor of claim 1, wherein the size of the ceramic capacitor is 0.4 mm long, 0.2 mm wide and 0.2 mm high. 2. The ceramic capacitor of claim 1, wherein the size of the ceramic capacitor is 3.2 mm long, 1.6 mm wide and 1.6 mm high. 2. The ceramic capacitor according to claim 1, containing 0.10 atm % or more and 0.30 atm % or less of Mn as said first subcomponent. 2. The ceramic capacitor according to claim 1, containing 0.5 atm % or more and 0.7 atm % or less of Mg as said second subcomponent. 2. The ceramic capacitor according to claim 1, containing 0.6 atm % or more and 0.8 atm % or less of a rare earth element as said third subcomponent. 2. The ceramic capacitor according to claim 1, wherein the fourth subcomponent contains 0.18 atm % or more and 0.27 atm % or less of V. 2. The ceramic capacitor according to claim 1, containing Si in an amount of 0.5 atm % or more and 0.8 atm % or less as said fifth subcomponent. 2. The ceramic capacitor according to claim 1, wherein the sixth subcomponent contains 0.1 atm % or more and 0.4 atm % or less of Ca. _{The ceramic capacitor according to claim 1, wherein said BaTiO3 is BamTiO3 ( 0.9990≤m≤1.0015} ). 2. The ceramic capacitor according to claim 1, wherein the BaTiO ₃ has an average particle size of 300 nm or more and 360 nm or less. 2. The ceramic capacitor according to claim 1, further comprising a cover layer containing contents of the main component and the first to sixth subcomponents of the dielectric layer in the stacking direction of the laminate. 2. The ceramic capacitor according to claim 1, wherein said ceramic capacitor satisfies EIA standard X7R characteristics.

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