JP2022088409A - Ceramic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic capacitor that can achieve both capacitance stability and high reliability.

SOLUTION: A ceramic capacitor includes a laminate in which dielectric layers and internal electrode layers are alternately laminated, and when BaTiO₃ is the main component and Ti of the main component is 100 atm%, the dielectric layer contains Mn of 0.05 atm% or more and 0.35 atm% or less as a first subcomponent, contains Mg of 0.4 atm% or more and 0.8 atm% or less as the second subcomponent, contains at least one rare earth element of Ho and Dy in total of 0.5 atm% or more and 0.9 atm% or less as a third subcomponent, contains V of 0.15 atm% or more and 0.30 atm% or less as a fourth subcomponent, contains Si of 0.4 atm% or more and 0.9 atm% or less as a fifth subcomponent, and contains Ca of 0.00 atm% or more and 0.45 atm% or less as a sixth subcomponent, and the average particle size of the ceramic particles constituting the dielectric layer is 280 nm or more and 380 nm or less.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to ceramic capacitors.

Ceramic capacitors are increasingly used in high temperature environments, including those for automobiles. Accordingly, ceramic capacitors are required to have capacitance stability under high temperature and high reliability under high temperature load. In recent years, it has become one of the important characteristics to satisfy the X7R characteristics of the EIA standard (the rate of change in capacity is within ± 15% when the temperature is 25 ° C. in the range of −55 ° C. to 125 ° C.). Therefore, a dielectric that satisfies the X7R characteristics has been proposed by adjusting and designing the dielectric composition and the fine structure (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2010-199268

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

The present invention has been made in view of the above problems, and an object of the present invention is to provide a ceramic capacitor capable of achieving both capacitance stability and high reliability.

The ceramic capacitor according to the present invention includes a laminate in which dielectric layers and internal electrode layers are alternately laminated, and the dielectric layer contains BaTiO ₃ as a main component and Ti as the main component is 100 atm%. In some cases, Mn is contained in an amount of 0.05 atm% or more and 0.35 atm% or less as a first sub-component, Mg is contained in an amount of 0.4 atm% or more and 0.8 atm% or less as a second sub-component, and Ho and Dy are contained as a third sub-component. It contains at least one rare earth element in total of 0.5 atm% or more and 0.9 atm% or less, V as a fourth subcomponent of 0.15 atm% or more and 0.30 atm% or less, and Si as a fifth subcomponent. It contains 4 atm% or more and 0.9 atm% or less, contains Ca as a sixth auxiliary component in an amount of 0.00 atm% or more and 0.45 atm% or less, and the average particle size 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 in length, 0.125 mm in width, and 0.125 mm in height. The size of the ceramic capacitor may be 0.4 mm in length, 0.2 mm in width, and 0.2 mm in height. The size of the ceramic capacitor may be 3.2 mm in length, 1.6 mm in width, and 1.6 mm in height. Mn of 0.10 atm% or more and 0.30 atm% or less may be contained as the first subcomponent. As the second subcomponent, Mg of 0.5 atm% or more and 0.7 atm% or less may be contained. Rare earth elements of 0.6 atm% or more and 0.8 atm% or less may be contained as the third subcomponent. The fourth subcomponent may contain V of 0.18 atm% or more and 0.27 atm% or less. As the fifth subcomponent, Si may be contained in an amount of 0.5 atm% or more and 0.8 atm% or less. As the sixth subcomponent, Ca may be contained in an amount of 0.1 atm% or more and 0.4 atm% or less. The BaTiO ₃ may be Ba _m TiO ₃ (0.9990 ≦ m ≦ 1.0015). The average particle size of BaTiO ₃ may be 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 subcomponent to the sixth subcomponent in the stacking direction of the laminate. The ceramic capacitor may satisfy the X7R characteristics of the EIA standard.

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

It is a partial cross-sectional perspective view of a monolithic ceramic capacitor. It is a figure which illustrates the flow of the manufacturing method of a multilayer ceramic capacitor. It is a figure which shows the addition amount of the 1st sub-component to the 6th sub-component in an Example and a comparative example. It is a figure which shows the result of each measurement test with respect to an Example and a comparative example.

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

(Embodiment)
FIG. 1 is a partial cross-sectional perspective view of the multilayer ceramic capacitor 100 according to the embodiment. As illustrated in FIG. 1, the multilayer ceramic capacitor 100 includes a ceramic main body 10 having a substantially rectangular parallelepiped shape, and external electrodes 20a and 20b provided on two facing end faces of any one of the ceramic main bodies 10. 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 to the upper surface, the lower surface, and the 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 a dielectric layer 11 containing a ceramic material that functions as a dielectric and an internal electrode layer 12 that functions as a conductor layer are alternately laminated. The end edges of each internal electrode layer 12 are alternately exposed on the end face of the ceramic body 10 provided with the external electrode 20a and the end face provided with the external electrode 20b. As a result, each internal electrode layer 12 is alternately conducted to the external electrode 20a and the external electrode 20b. As a result, the laminated ceramic capacitor 100 has a structure in which a plurality of dielectric layers 11 are laminated via an internal electrode layer 12. Further, in the laminated structure of the dielectric layer 11 and the internal electrode layer 12, the internal electrode layer 12 is arranged on the outermost layer in the stacking direction, and the upper surface and the lower surface of the laminated body 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 has the same main components as the dielectric layer 11 and the ceramic material.

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

The internal electrode layer 12 contains a base metal such as Ni (nickel), Cu (copper), Sn (tin) as a main component. As the internal electrode layer 12, a noble metal such as Pt (platinum), Pd (palladium), Ag (silver), Au (gold) or an alloy 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 ABO ₃ . The perovskite structure contains ABO _3-α , which deviates from the stoichiometric composition. The perovskite is barium titanate containing Ba (barium) and Ti (titanium) and is represented by _Bamm TiO ₃ . Since barium titanate is a ferroelectric substance, a high dielectric constant is realized.

In the multilayer ceramic capacitor 100 according to the present embodiment, the dielectric layer 11 contains an auxiliary component, so that both capacitance stability and high reliability are compatible. Hereinafter, the details of the auxiliary components added to the dielectric layer 11 will be described.

The dielectric layer 11 contains Mn (manganese) as a first subcomponent. Mn has the effect of achieving good sinterability and improving the life characteristics of the monolithic ceramic capacitor 100. Thereby, high reliability of the monolithic ceramic capacitor 100 can be realized. However, if Mn is too small, high reliability may not be achieved. On the other hand, if the amount of Mn is too large, the insulating property may be lowered and the reliability may be lowered because the grain boundary resistance of the ceramic particles is lowered. Therefore, an upper limit and a lower limit are set for the Mn concentration in the dielectric layer 11. Specifically, the dielectric layer 11 contains Mn of 0.05 atm% or more and 0.35 atm% or less when the Ti of _Bamm TiO ₃ which is the main component ceramic of the dielectric layer 11 is 100 atm%. There is. The dielectric layer 11 may contain Mn of 0.10 atm% or more and 0.30 atm% or less when the Ti of _Bamm TiO ₃ which is the main component ceramic of the dielectric layer 11 is 100 atm%. preferable.

Next, the dielectric layer 11 contains Mg (magnesium) as a second subcomponent. Mg has functions such as grain growth control during firing, and realizes capacity stability and high reliability. However, if the amount of Mg is too small, sufficient capacitance stability may not be achieved. In addition, grain growth may occur in the sintering process, which may reduce reliability. On the other hand, if the amount of Mg is too large, the reliability may decrease due to the excessive acceptor. 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 Mg of 0.4 atm% or more and 0.8 atm% or less when the Ti of _Bamm TiO ₃ which is the main component ceramic of the dielectric layer 11 is 100 atm%. .. The dielectric layer 11 preferably contains Mg of 0.5 atm% or more and 0.7 atm% or less when the Ti of _Bamm TiO 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 an action of adjusting the balance of the solid solution sites (A site and B site) of the additive element, and realizes high reliability. However, if the rare earth element Re is too small, sufficient reliability may not be obtained. On the other hand, if the amount of the rare earth element Re is too large, the sintering property of the dielectric layer 11 may deteriorate due to the reason 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 is the total concentration of Ho and Dy. Specifically, the dielectric layer 11 contains a rare earth element Re of 0.5 atm% or more and 0.9 atm% or less when the Ti of _Bamm TiO ₃ which is the main component ceramic of the dielectric layer 11 is 100 atm%. I'm out. The dielectric layer 11 contains a rare earth element Re of 0.6 atm% or more and 0.8 atm% or less when the Ti of _Bamm TiO ₃ , which is the main component ceramic of the dielectric layer 11, is 100 atm%. Is preferable.

Next, the dielectric layer 11 contains V (vanadium) as a fourth subcomponent. V has actions such as suppression of oxygen defect generation and control of the fine structure of ceramic, and realizes high reliability and capacitance stability. However, if V is too small, sufficient high reliability and sufficient capacitance stability may not be obtained. On the other hand, if the amount of V is too large, sufficient capacitance stability may not be obtained because the electric resistance is lowered or the target ceramic fine structure cannot be generated. Therefore, an upper limit and a lower limit are set for the V concentration in the dielectric layer 11. Specifically, the dielectric layer 11 contains V of 0.15 atm% or more and 0.30 atm% or less when the Ti of _Bamm TiO ₃ which is the main component ceramic of the dielectric layer 11 is 100 atm%. .. The dielectric layer 11 preferably contains V of 0.18 atm% or more and 0.27 atm% or less when the Ti of _Bamm TiO ₃ which is the main component ceramic of the dielectric layer 11 is 100 atm%. ..

Next, the dielectric layer 11 contains Si (silicon) as a fifth subcomponent. Since Si functions as a sintering aid, good sintering is realized. However, if the amount of Si is too small, it becomes difficult to sinter at an appropriate temperature (for example, 1260 ° C. or lower), 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 in the sintering process due to excessive formation 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 Si in an amount of 0.4 atm% or more and 0.9 atm% or less when the Ti of _Bamm TiO ₃ which is the main component ceramic of the dielectric layer 11 is 100 atm%. .. The dielectric layer 11 preferably contains Si in an amount of 0.5 atm% or more and 0.8 atm% or less when the Ti of _Bamm TiO ₃ which is the main component ceramic of the dielectric layer 11 is 100 atm%. ..

Next, the dielectric layer 11 contains Ca (calcium) as a sixth subcomponent. Ca has a function as a sintering aid and can be used for adjusting the A / B ratio, which is the molar ratio of the A-site element and the B-site element. However, if there is too much Ca, sufficient capacity stability may not be obtained due to the excess of A-site component. Therefore, an upper limit is set for the Ca concentration in the dielectric layer 11. Specifically, the dielectric layer 11 contains Ca in an amount of 0.00 atm% or more and 0.45 atm% or less when the Ti of _Bamm TiO ₃ which is the main component ceramic of the dielectric layer 11 is 100 atm%. .. "Ca is 0.00 atm% or more" means that Ca may not be contained. The dielectric layer 11 preferably contains Ca in an amount of 0.10 atm% or more and 0.40 atm% or less when the Ti of _Bamm TiO ₃ which is the main component ceramic of the dielectric layer 11 is 100 atm%. ..

Next, if the m of Ba _m TiO ₃ , 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, capacitance stability may not be obtained. Therefore, m takes a value of m ≦ 1.0015.

Next, if the average particle size of the _Bamm TiO ₃ which is the main component ceramic of the dielectric layer 11 is too small, the capacitance stability may decrease because the target ceramic fine structure cannot be obtained. .. On the other hand, if the average particle size is too large, the number of grain boundaries of the ceramic may be reduced, which may lead to a problem that the insulation resistance is lowered and the reliability is also lowered. Therefore, an upper limit and a lower limit are set for the average particle size of _Bam TiO ₃ . Specifically, the average particle size of _Bam TiO ₃ is 280 nm or more and 380 nm or less. The average particle size of _Bam TiO ₃ is preferably 300 nm or more and 360 nm or less.

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

As described above, by defining the contents of the first subcomponent to the sixth subcomponent in the dielectric layer 11, the value of _m of Bam TiO ₃ , and the average particle size of _Bam TiO ₃ are specified. It is possible to achieve both capacitance stability and high reliability. The material of the cover layer 13 has the same main components as the dielectric layer 11 and the ceramic material, but the cover layer 13 also contains the same first to sixth sub-components as the dielectric layer 11. It is preferable to specify the value of m of Ba _m TiO ₃ and to specify the average particle size of Ba _m TiO ₃ .

Subsequently, a method for manufacturing the monolithic ceramic capacitor 100 will be described. FIG. 2 is a diagram illustrating a flow of a manufacturing method of the monolithic ceramic capacitor 100.

(Raw material powder preparation process)
First, a dielectric material for forming the dielectric layer 11 is prepared. The A-site element and the B-site element contained in the dielectric layer 11 are usually contained in the dielectric layer 11 in the form of a sintered body of particles of ABO ₃ . For example, barium titanate is a tetragonal compound having a perovskite structure and exhibits a high dielectric constant. This BaTIO ₃ can be generally 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 the general formula Am BO ₃ representing the perovskite structure of barium titanate, the titanium raw material and the barium raw material are reacted so that _m takes a value of 0.9990 ≦ m ≦ 1.0015. As a method for synthesizing the ceramic constituting the dielectric layer 11, various methods have been conventionally known, and for example, a solid phase synthesis method, a sol-gel synthesis method, a hydrothermal synthesis method and the like are known.

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 (gadrinium), Tb (terbium), Dy, Ho, Er ( Oxides of (erbium), Tm (ttrium) and Yb (yttrium)), and oxides of Co (cobalt), Ni, Li (lithium), B (boron), Na (sodium), K (potassium) and Si. Alternatively, glass may be mentioned.

In the present embodiment, when Ti of _Bamm TiO ₃ which is the main component ceramic of the ceramic powder is set to 100 atm%, Mn is added as the first subcomponent by 0.05 atm% or more and 0.35 atm% or less, and the second Mg is added as an auxiliary component in an amount of 0.4 atm% or more and 0.8 atm% or less, and at least one of Ho and D, a rare earth element Re, is added as a third auxiliary component in an amount of 0.5 atm% or more and 0.9 atm% or less. 4 V is added as a subcomponent of 0.15 atm% or more and 0.30 atm% or less, Si is added as a fifth subcomponent of 0.4 atm% or more and 0.9 atm% or less, and Ca is added as a sixth subcomponent of 0.00 atm%. Add 0.45 atm% or more and 0.45 atm% or less.

In the present embodiment, preferably, first, the particles of barium titanate are mixed with a compound containing an additive compound and calcined at 820 to 1150 ° C. Subsequently, the obtained ceramic particles are wet-mixed together with the added compound, dried and pulverized 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 may be combined with the classification treatment to adjust the particle size, if necessary.

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

Next, by printing a metal conductive paste containing an organic binder for forming an internal electrode on the surface of the green sheet by screen printing, gravure printing, or the like, an internal electrode layer pattern that is alternately drawn out to a pair of external electrodes having different polarities. Is arranged and used as a pattern forming sheet. Ceramic particles are added to the metal conductive paste as a co-material. The main component of the ceramic particles is not particularly limited, but is preferably the same as the main component ceramic of the dielectric layer 11. For example, BaTiO ₃ having an average particle diameter of 50 nm or less may be uniformly dispersed.

Next, a cover sheet is formed by laminating a plurality of green sheets, a plurality of pattern forming sheets are laminated on the cover sheet, and a plurality of green sheets are laminated on the obtained laminate. Form a cover sheet with. The obtained laminate is cut into a predetermined size.

(Baking process)
The molded product thus obtained is subjected to a binder removal treatment in an _N2 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 grows into grains. In this way, the ceramic body 10 is obtained. The firing conditions may be adjusted to other conditions so that the average particle size of the _Bamm TiO ₃ which is the main component ceramic of the dielectric layer 11 after firing is 280 nm or more and 380 nm or less.

(Reoxidation process)
Then, the reoxidation treatment may be performed at 600 ° C. to 1000 ° C. in an _N2 gas atmosphere.

(External electrode forming process)
Next, the conductive paste for forming the external electrodes 20a and 20b is applied to the two end faces where the internal electrode layer pattern of the obtained sintered body is 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, a temperature of about 800 ° C. to 900 ° C.). As a result, the external electrodes 20a and 20b are baked. After that, a metal coating such as Cu, Ni, Sn may be applied by a plating treatment. Before the above-mentioned firing step, the conductive paste for forming the external electrodes 20a and 20b may be applied to the two end faces of the laminated body of the green sheet, and the laminated body and the conductive paste may be fired at the same time in the firing step.

In the present embodiment, when the Ti of the perovskite structure is 100 atm% with respect to the ceramic powder having the perovskite structure represented by Ba _m TiO ₃ (0.9990 ≦ m ≦ 1.0015), the first Mn is added as an accessory component in an amount of 0.05 atm% or more and 0.35 atm% or less. Mg is added as a second subcomponent in an amount of 0.4 atm% or more and 0.8 atm% or less. At least one rare earth element of Ho and Dy is added as a third subcomponent in an amount of 0.5 atm% or more and 0.9 atm% or less. V is added as a fourth subcomponent in an amount of 0.15 atm% or more and 0.30 atm% or less. Si is added as a fifth auxiliary component in an amount of 0.4 atm% or more and 0.9 atm% or less. Ca is added as a sixth auxiliary component in an amount of 0.00 atm% or more and 0.45 atm% or less. Further, in the dielectric layer 11 after firing, the conditions of the firing step are adjusted so that the average particle size of _Bamm TiO ₃ is 280 nm or more and 380 nm or less. As a result, in the monolithic ceramic capacitor 100, both capacitance stability and high reliability can be achieved at the same time.

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

Hereinafter, the monolithic ceramic capacitor according to the embodiment was produced and its characteristics were investigated.

_Bamm TiO ₃ powder was prepared as the main component ceramics 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 auxiliary component.

The barium titanate powder and the first to sixth sub-components were weighed in a predetermined ratio, and sufficiently wet-mixed and pulverized with a ball mill to obtain a dielectric material. Butyral-based as an organic binder, toluene and ethyl alcohol as a solvent were added to the dielectric material, and zirconia beads were used as a dispersion medium to obtain a slurry. The amount of zirconia beads used in this case was such that Zr was 0.20 atm% or more and 0.26 atm% or less when Ti of _Bamm TiO ₃ was 100 atm%.

(Example 1)
In Example 1, when the Ti content of the _Bamm TiO ₃ powder is 100 atm%, MnCO ₃ is added so that Mn is 0.05 atm% as the first sub-component, and Mg is 0. as the second sub-component. MgO was added so as to be 60 atm%, Ho ₂ O ₃ was added as the third subcomponent so that Ho was 0.68 atm%, and V was added so that V was 0.25 atm% as the fourth subcomponent. ₂ O ₅ was added, SiO ₂ was added as a fifth subcomponent so that Si was 0.50 atm%, and CaCO ₃ was added as a sixth subcomponent so that Ca was 0.15 atm%. The value of was 0.9997.

(Example 2)
In Example 2, the same procedure as in Example 1 was carried out except that MnCO ₃ was added as the first subcomponent so that Mn was 0.15 atm%.

(Example 3)
In Example 3, the same procedure as in Example 1 was carried out except that MnCO ₃ was added as the first subcomponent so that Mn was 0.35 atm%.

(Comparative Example 1)
In Comparative Example 1, the same procedure as in Example 1 was carried out except that the first subcomponent was not added and the value of m was 0.9996.

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

(Example 4)
In Example 4, when the Ti content of the _Bamm TiO ₃ powder is 100 atm%, MnCO ₃ is added so that Mn is 0.15 atm% as the first sub-component, and Mg is 0. as the second sub-component. MgO was added so as to be 40 atm%, Ho ₂ O ₃ was added as a third subcomponent so that Ho was 0.68 atm%, and V was added so that V was 0.25 atm% as a fourth subcomponent. ₂ O ₅ was added, SiO ₂ was added as a fifth subcomponent so that Si was 0.50 atm%, and CaCO ₃ was added as a sixth subcomponent so that Ca was 0.15 atm%. The value of was 0.9996.

(Example 5)
In Example 5, MgO was added so that Mg was 0.60 atm% as the second subcomponent, and the value of m was 0.9997, which was the same as in Example 4.

(Example 6)
In Example 6, MgO was added so that Mg was 0.80 atm% as the second subcomponent, and the value of m was 0.9993, which was the same as in Example 4.

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

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

(Example 7)
In Example 7, when the Ti content of the _Bamm TiO ₃ powder is 100 atm%, MnCO ₃ is added so that Mn is 0.15 atm% as the first sub-component, and Mg is 0. as the second sub-component. MgO was added so as to be 60 atm%, Ho ₂ O ₃ was added as a third subcomponent so that Ho was 0.50 atm%, and V was added so that V was 0.25 atm% as a fourth subcomponent. ₂ O ₅ was added, SiO ₂ was added as a fifth subcomponent so that Si was 0.50 atm%, and CaCO ₃ was added as a sixth subcomponent so that Ca was 0.15 atm%. The value of was 0.9999.

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

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

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

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

(Example 10)
In Example 10, when the Ti content of the _Bamm TiO ₃ powder is 100 atm%, MnCO ₃ is added so that Mn is 0.15 atm% as the first sub-component, and Mg is 0. as the second sub-component. MgO was added so as to be 60 atm%, Ho ₂ O ₃ was added as the third subcomponent so that Ho was 0.68 atm%, and V was added so that V was 0.15 atm% as the fourth subcomponent. ₂ O ₅ was added, SiO ₂ was added as a fifth subcomponent so that Si was 0.60 atm%, and CaCO ₃ was added as a sixth subcomponent so that Ca was 0.15 atm%. The value of was 1.0001.

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

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

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

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

(Example 13)
In Example 13, when the Ti content of the _Bamm TiO ₃ powder is 100 atm%, MnCO ₃ is added so that Mn is 0.15 atm% as the first sub-component, and Mg is 0. as the second sub-component. MgO was added so as to be 60 atm%, Ho ₂ O ₃ was added as the third subcomponent so that Ho was 0.68 atm%, and V was added so that V was 0.25 atm% as the fourth subcomponent. ₂ O ₅ was added, SiO ₂ was added as the fifth subcomponent so that Si was 0.40 atm%, and CaCO ₃ was added as the sixth subcomponent so that Ca was 0.15 atm%. The value of was 0.9998.

(Example 14)
In Example 14, SiO ₂ was added so that Si was 0.60 atm% as the fifth subcomponent, and the value of m was 0.9995, which was the same as in Example 13.

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

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

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

(Example 16)
In Example 16, when the Ti content of the _Bamm TiO ₃ powder is 100 atm%, MnCO ₃ is added so that Mn is 0.15 atm% as the first sub-component, and Mg is 0. as the second sub-component. MgO was added so as to be 60 atm%, Ho ₂ O ₃ was added as the third subcomponent so that Ho was 0.68 atm%, and V was added so that V was 0.25 atm% as the fourth subcomponent. ₂ O ₅ was added, SiO ₂ was added so that Si was 0.50 atm% as the fifth sub-component, and the sixth sub-component was not added, and the value of m was set to 1.0002.

(Example 17)
In Example 17, the same procedure as in Example 16 was carried out except that CaO was added so that Ca was 0.25 atm% as the sixth subcomponent.

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

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

(Example 19)
In Example 19, when the Ti content of the _Bamm TiO ₃ powder is 100 atm%, MnCO ₃ is added so that Mn is 0.15 atm% as the first sub-component, and Mg is 0. as the second sub-component. MgO was added so as to be 60 atm%, Ho ₂ O ₃ was added as the third subcomponent so that Ho was 0.68 atm%, and V was added so that V was 0.25 atm% as the fourth subcomponent. ₂ O ₅ was added, SiO ₂ was added as a fifth subcomponent so that Si was 0.50 atm%, and CaCO ₃ was added as a sixth subcomponent so that Ca was 0.15 atm%. The value of was 0.9990.

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

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

(Comparative Example 12)
In Comparative Example 12, it was the same as in Example 19 except that the value of m was 0.9985.

(Comparative Example 13)
In Comparative Example 13, it was the same as in Example 19 except that the value of m was 1.0020.

(Example 22)
In Example 22, when the Ti content of the _Bamm TiO ₃ powder is 100 atm%, MnCO ₃ is added so that Mn is 0.15 atm% as the first sub-component, and Mg is 0. as the second sub-component. MgO was added so as to be 60 atm%, Dy ₂ O ₃ was added as the third subcomponent so that Dy was 0.68 atm%, and V was added so that V was 0.25 atm% as the fourth subcomponent. ₂ O ₅ was added, SiO ₂ was added as a fifth subcomponent so that Si was 0.50 atm%, and CaCO ₃ was added as a sixth subcomponent so that Ca was 0.15 atm%. The value of was 0.9997.

(Comparative Example 14)
In Comparative Example 14, when the Ti content of the _Bamm TiO ₃ powder was 100 atm%, MnCO ₃ was added so that Mn was 0.12 atm% as the first sub-component, and Mg was 0. as the second sub-component. MgO was added so as to be 80 atm%, Ho ₂ O ₃ was added as the third subcomponent so that Ho was 1.30 atm%, and V was added so that V was 0.18 atm% as the fourth subcomponent. ₂ O ₅ was added, SiO ₂ was added as a fifth subcomponent so that Si was 0.90 atm%, and CaCO ₃ was added as a sixth subcomponent so that Ca was 0.20 atm%. The value of was 1.0002.

FIG. 3 shows the addition amounts of the first sub-component to the sixth sub-component and the value of m in Examples 1 to 22 and Comparative Examples 1 to 14. In addition, in FIG. 3, the blank means that it was not added intentionally.

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

The obtained laminate was cut to a predetermined size and then degreased in an _N2 atmosphere. Then, firing was carried out for 2 hours in a reducing atmosphere at 1230 ° C. In the process of lowering the temperature of the calcination, the oxygen partial pressure was increased and the reoxidation treatment was performed. As a result, the ceramic body 10 was obtained. Then, a Cu external electric paste containing a glass frit was applied to the two end faces of the ceramic main body 10 and baked in an _N2 atmosphere to obtain a laminated ceramic capacitor 100 having a size of 3.2 mm × 1.6 mm × 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 is 330 nm in Example 1, 327 nm in Example 2, 335 nm in Example 3, and 345 nm in Example 4, and is an example. 5 is 327 nm, Example 6 is 337 nm, Example 7 is 331 nm, Example 8 is 320 nm, Example 9 is 323 nm, Example 10 is 313 nm, and Example 11 is. It is 311 nm, 315 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. It was 314 nm in Example 18, 340 nm in Example 19, 311 nm in Example 20, 307 nm in Example 21, and 330 nm in Example 22. 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 for comparison. It is 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 Comparative Example 14. It was 198 nm.

(analysis)
Each measurement test was carried out for each laminated ceramic capacitor 100 obtained in Examples 1 to 22 and Comparative Examples 1 to 14.

(Relative permittivity ε _r , Tan δ test)
The heat was rehydrated at 150 ° C. for 1 hour, and after 24 hours, the capacity and Tan δ of the monolithic ceramic capacitor 100 were measured with an LCR meter. The measurement conditions were 1 kHz-1 Vrms. From the capacitance C, the relative permittivity ε _r of the dielectric layer 11 was obtained by using the effective intersection area S, the number of layers n, the thickness t of the dielectric layer 11, and the vacuum permittivity ε ₀ according to the following equation (1). .. The effective crossing area is the total value of the areas where the adjacent internal electrode layers 12 face each other in the capacitance region where the 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 was maximized was measured. Moreover, the ratio (MAX / 125 ° C.) of the capacity C at the MAX temperature and the capacity C at 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 is evaluated as "○", and the others are rejected as "×". Judged.

(Life test)
For MTTF, when a voltage (electric field) of 30 V / μm was applied at 150 ° C., the time until the resistance value decreased by 3 orders of magnitude from the insulation resistance value before the test was measured.

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

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

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

In Comparative Example 7, the MTTF was as short as 5 hours, and sufficient reliability could not be obtained. Moreover, sufficient capacity stability could not be obtained. It is considered that this is because the fourth sub-ingredient was not added. In Comparative Example 8, sufficient capacitance stability could not be obtained. It is considered that this is because the amount of the fourth auxiliary component added exceeded 0.30 atm%.

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

In Comparative Example 11, sufficient capacitance stability could not be obtained. It is considered that this is because the addition amount of the sixth auxiliary component exceeded 0.45 atm%.

In Comparative Example 12, grain growth occurred and sufficient capacity stability could not be obtained. It is considered that this is because m of Ba _m TiO ₃ was less than 0.9990. In Comparative Example 13, sufficient capacitance stability could not be obtained. It is considered that this is because m exceeded 1.0015.

In Comparative Example 14, sufficient capacitance stability could not be obtained. It is considered that this is because the particle size of the dielectric layer 11 is less than 280 nm.

On the other hand, in Examples 1 to 22, the MTTF became longer and passed the X7R test. That is, it was possible to achieve both high reliability and capacity stability. This is as the first subcomponent when the Ti of the perovskite structure is 100 atm% with respect to the ceramic powder having the perovskite structure represented by Ba _m TiO ₃ (0.9990 ≦ m ≦ 1.0015). Mn is added in an amount of 0.05 atm% or more and 0.35 atm% or less, Mg is added in an amount of 0.4 atm% or more and 0.8 atm% or less as a second subcomponent, and at least one of Ho and Dy is rare earth as a third subcomponent. The element Re is added in an amount of 0.5 atm% or more and 0.9 atm% or less, V is added in an amount of 0.15 atm% or more and 0.30 atm% or less as a fourth auxiliary component, and Si is added in an amount of 0.4 atm% or more and 0.4 atm% or less as a fifth auxiliary component. 9 atm% or less was added, Ca was added at 0.00 atm% or more and 0.45 atm% or less as the sixth auxiliary component, and the average particle size of _Bam TiO ₃ in the dielectric layer 11 after firing was 280 nm or more and 380 nm or less. Is considered to be.

Although the examples of the present invention have been described in detail above, the present invention is not limited to the specific examples thereof, and various modifications and variations are made within the scope of the gist of the present invention described in the claims. It can be changed.

10 Ceramic body 11 Dielectric layer 12 Internal electrode layer 13 Cover layer 20a, 20b External electrode 100 Multilayer ceramic capacitor

Claims (14)

A laminate in which dielectric layers and internal electrode layers are alternately laminated is provided.
When BaTiO ₃ is the main component and Ti of the main component is 100 atm%, the dielectric layer contains Mn of 0.05 atm% or more and 0.35 atm% or less as the first sub-component, and is used as the second sub-component. It contains Mg of 0.4 atm% or more and 0.8 atm% or less, and contains at least one rare earth element of Ho and Dy as a third subcomponent in total of 0.5 atm% or more and 0.9 atm% or less as a fourth subcomponent. V is contained in an amount of 0.15 atm% or more and 0.30 atm% or less, Si is contained in an amount of 0.4 atm% or more and 0.9 atm% or less as a fifth auxiliary component, and Ca is contained in an amount of 0.00 atm% or more and 0.45 atm% or less as a sixth auxiliary component. Including,
A ceramic capacitor having an average particle diameter of 280 nm or more and 380 nm or less of the ceramic particles constituting the dielectric layer. The ceramic capacitor according to claim 1, wherein the size of the ceramic capacitor is 0.2 mm in length, 0.125 mm in width, and 0.125 mm in height. The ceramic capacitor according to claim 1, wherein the size of the ceramic capacitor is 0.4 mm in length, 0.2 mm in width, and 0.2 mm in height. The ceramic capacitor according to claim 1, wherein the size of the ceramic capacitor is 3.2 mm in length, 1.6 mm in width, and 1.6 mm in height. The ceramic capacitor according to claim 1, which contains Mn of 0.10 atm% or more and 0.30 atm% or less as the first subcomponent. The ceramic capacitor according to claim 1, which contains Mg of 0.5 atm% or more and 0.7 atm% or less as the second subcomponent. The ceramic capacitor according to claim 1, which contains a rare earth element of 0.6 atm% or more and 0.8 atm% or less as the third subcomponent. The ceramic capacitor according to claim 1, which contains V of 0.18 atm% or more and 0.27 atm% or less as the fourth subcomponent. The ceramic capacitor according to claim 1, which contains Si of 0.5 atm% or more and 0.8 atm% or less as the fifth subcomponent. The ceramic capacitor according to claim 1, which contains Ca of 0.1 atm% or more and 0.4 atm% or less as the sixth subcomponent. The ceramic capacitor according to claim 1, wherein the BaTiO ₃ is a Ba _m TiO ₃ (0.9990 ≦ m ≦ 1.0015). The ceramic capacitor according to claim 1, wherein the average particle size of BaTiO ₃ is 300 nm or more and 360 nm or less. The ceramic capacitor according to claim 1, further comprising a cover layer containing the main component of the dielectric layer and the contents of the first subcomponent to the sixth subcomponent in the stacking direction of the laminate. The ceramic capacitor according to claim 1, wherein the ceramic capacitor satisfies the X7R characteristics of the EIA standard.

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