CN110233048B

CN110233048B - Multilayer ceramic capacitor and ceramic material powder

Info

Publication number: CN110233048B
Application number: CN201910167134.5A
Authority: CN
Inventors: 谷口克哉; 曾我部刚
Original assignee: Taiyo Yuden Co Ltd
Current assignee: Taiyo Yuden Co Ltd
Priority date: 2018-03-06
Filing date: 2019-03-06
Publication date: 2022-05-13
Anticipated expiration: 2039-03-06
Also published as: JP2019161217A; JP2023021997A; TWI784140B; CN110233048A; TW201945320A; JP7338963B2; KR20190106699A

Abstract

The present application provides a laminated ceramic capacitor, which includes: a stacked body in which each of a plurality of dielectric layers and each of a plurality of internal electrode layers are alternately stacked; wherein the main component of the dielectric layer is a ceramic material, wherein the main phase of the ceramic material has the general formula ABO₃The perovskite structure of (a), wherein the B site of the ceramic material comprises an element that serves as a donor; wherein the A site and the B site of the ceramic material comprise a rare earth element, wherein (the amount of the rare earth element substitutionally solid-dissolved in the A site)/(the amount of the rare earth element substitutionally solid-dissolved in the B site) is 0.75 or more and 1.25 or less.

Description

Multilayer ceramic capacitor and ceramic material powder

Technical Field

Certain aspects of the present invention relate to a laminated ceramic capacitor and a ceramic material powder.

Background

A dielectric material that realizes sufficient reliability characteristics is required for a laminated ceramic capacitor having a dielectric layer with a small thickness. For example, it is effective to dissolve a specific element in the material powder in advance. Japanese patent application laid-open No. 2016-.

Disclosure of Invention

However, recently, the thickness of the dielectric layer is reduced and the number of stacked dielectric layers is increased. Further, further improvement in life characteristics is required. Further, improvement of insulation characteristics is required. Therefore, it is difficult to achieve higher reliability only by using a method of reducing the amount of oxygen defects by the donor element.

The invention aims to provide a laminated ceramic capacitor and ceramic material powder which can realize high reliability.

According to an aspect of the present invention, there is provided a laminated ceramic capacitor including: a stacked body in which each of a plurality of dielectric layers and each of a plurality of internal electrode layers are alternately stacked; wherein the main component of the dielectric layer is a ceramic material, wherein the main phase of the ceramic material has the general formula ABO₃The perovskite structure of (a), wherein the B site of the ceramic material comprises an element that serves as a donor; wherein the A site and the B site of the ceramic material comprise a rare earth element, wherein (amount of the rare earth element substitutionally solid-dissolved in the A site)/(substitutional solid-dissolved in the A site)/(The amount of the rare earth element in the B site) is 0.75 or more and 1.25 or less.

According to another aspect of the present invention, there is provided a ceramic material powder comprising: a main phase having the formula ABO₃A perovskite structure of (a); an element serving as a donor in a B site of the perovskite structure; and rare earth elements in the a site and the B site of the perovskite structure, wherein (the amount of the rare earth element substitutionally solid-dissolved in the a site)/(the amount of the rare earth element substitutionally solid-dissolved in the B site) is 0.75 or more and 1.25 or less.

Drawings

Fig. 1 shows a partial perspective view of a laminated ceramic capacitor; and is

Fig. 2 shows a method for manufacturing a laminated ceramic capacitor.

Detailed Description

A description is given of embodiments with reference to the accompanying drawings.

[ embodiment ]

Fig. 1 shows a partial perspective view of a laminated ceramic capacitor 100 according to an embodiment. As shown in fig. 1, the laminated ceramic capacitor 100 includes a laminated chip 10 having a rectangular parallelepiped shape and a pair of

external electrodes

20a and 20b respectively provided on both end faces of the laminated chip 10 facing each other. Of the four surfaces other than the two end surfaces of the laminated chip 10, two surfaces other than the upper surface and the lower surface of the laminated chip 10 in the lamination direction are referred to as side surfaces. The

external electrodes

20a and 20b extend to the upper surface, the lower surface, and both side surfaces. However, the

external electrodes

20a and 20b are spaced apart from each other.

The stacked chip 10 has a structure designed to have dielectric layers 11 and internal electrode layers 12 alternately stacked. The main component of the dielectric layer 11 is a ceramic material acting as a dielectric material. The main component of the internal electrode layers 12 is a metallic material, such as a base metal material. The edges of the internal electrode layers 12 are alternately exposed at a first end face of the laminated chip 10 and at a second end face of the laminated chip 10 different from the first end face. In this embodiment, the first face faces the second face. The external electrode 20a is provided on the first end face. The external electrode 20b is disposed on the second end face. Therefore, the internal electrode layers 12 are alternately conducted to the external electrodes 20a and the external electrodes 20 b. Therefore, the laminated ceramic capacitor 100 has the following structure: in which a plurality of dielectric layers 11 are stacked, and the internal electrode layers 12 are sandwiched between every two dielectric layers 11. In the stacked body of the dielectric layers 11 and the internal electrode layers 12, the internal electrode layers 12 are positioned at the outermost layers in the stacking direction. The upper and lower surfaces of the laminate are internal electrode layers 12 covered with a cover layer 13. The main component of the cover layer 13 is a ceramic material. For example, the main component of the cover layer 13 is the same as that of the dielectric layer 11.

For example, the laminated ceramic capacitor 100 may have a length of 0.25mm, a width of 0.125mm, and a height of 0.125 mm. The laminated ceramic capacitor 100 may have a length of 0.4mm, a width of 0.2mm and a height of 0.2 mm. The laminated ceramic capacitor 100 may have a length of 0.6mm, a width of 0.3mm and a height of 0.3 mm. The laminated ceramic capacitor 100 may have a length of 1.0mm, a width of 0.5mm, and a height of 0.5 mm. The laminated ceramic capacitor 100 may have a length of 3.2mm, a width of 1.6mm and a height of 1.6 mm. The laminated ceramic capacitor 100 may have a length of 4.5mm, a width of 3.2mm and a height of 2.5 mm. However, the size of the multilayer ceramic capacitor 100 is not limited.

The main component of the internal electrode layers 12 is a base metal such as nickel (Ni), copper (Cu), tin (Sn), or the like. The internal electrode layers 12 may be made of a noble metal such as platinum (Pt), palladium (Pd), silver (Ag), gold (Au), or an alloy thereof.

The dielectric layer 11 is mainly composed of a main phase with a general formula ABO₃Is represented by and has the composition of a ceramic material of perovskite structure. The perovskite structure comprises an ABO having a non-stoichiometric composition_3-α. The ceramic material is, for example, BaTiO₃(barium titanate), CaZrO₃(calcium zirconate), CaTiO₃(calcium titanate), SrTiO₃(strontium titanate) and Ba having perovskite Structure_1-x-yCa_xSr_yTi_1-zZr_zO₃(0≤x≤1，0≤y≤1，0≤z≤1)。

For the purpose of downsizing the laminated ceramic capacitor 100 and increasing the capacitance of the laminated ceramic capacitor 100, the thickness of the dielectric layer 11 needs to be reduced. However, when the thickness of the dielectric layer 11 is reduced, the life characteristics may be deteriorated due to insulation breakdown. And reliability may be deteriorated.

A description will be given of the reliability deterioration. The main component of the dielectric layer 11 is a ceramic material having a main phase with a chemical formula ABO₃The perovskite-structured ceramic material powder is shown. During firing, the ceramic material powder is exposed to a reducing atmosphere. Thus, in ABO₃Oxygen defects may occur. When the multilayer ceramic capacitor 100 is used, a voltage is repeatedly applied to the dielectric layer 11. In this case, oxygen defects move in the dielectric layer 11. Thus, the barrier is broken. That is, oxygen defects in the perovskite structure cause deterioration in reliability of the dielectric layer 11.

Thus, the B site of the perovskite structure includes an element that serves as a donor. That is, the element substitution serving as a donor is solid-soluble in the B site. For example, the element serving as a donor is, for example, Mo (molybdenum), Nb (niobium), Ta (tantalum), W (tungsten), or the like. When the element serving as a donor is substitutionally solid-dissolved in the B site, oxygen defects in the perovskite structure are suppressed. Therefore, the lifetime of the dielectric layer 11 can be extended, and the reliability can be improved.

In the B site, when the amount of the element serving as a donor is too low, oxygen defects may not be sufficiently suppressed. Thus, preferably, the amount of the element that acts as a donor and replaces the solid solution in the B site has a lower limit. For example, it is preferable that the amount of the element serving as a donor and substitutionally solid-dissolved in the B site is 0.05 atm% or more, assuming that the amount of the main component element of the B site is 100 atm%. More preferably, the amount is 0.1 atm% or more.

On the other hand, when the amount of the element serving as a donor in the B site is excessively high, a defect such as a decrease in insulation resistance of the laminated ceramic capacitor 100 may occur. Therefore, preferably, there is an upper limit to the amount of the element that acts as a donor and replaces the solid solution in the B site. For example, it is preferable that the amount of the element which serves as a donor and is substitution-immobilized in the B site is 0.3 atm% or less. More preferably, the amount is 0.25 atm% or less.

When the dielectric layer 11, whose main component is a ceramic material using a ceramic material powder whose main phase has a perovskite structure, is re-oxidized after being fired in a reducing atmosphere, oxygen defects can be further suppressed. When both the a site and the B site include a rare earth element (substitution solid-dissolved with a rare earth element) during the reoxidation, the amount of oxygen defects after firing is suppressed. Therefore, long-life characteristics can be realized while maintaining IR (insulation resistance) characteristics. Therefore, high reliability can be achieved. Thus, in embodiments, the rare earth element substitutions are solid soluble in both the a site and the B site.

When the amount of the rare earth element that is substitutionally solid-dissolved in the a site is excessively large compared to the amount of the rare earth element that is substitutionally solid-dissolved in the B site, the amount of the donor doped in the perovskite may be excessively large. In this case, the insulation characteristics may be deteriorated. On the other hand, when the amount of the rare earth element replacing solid-dissolved in the B site is excessively large compared to the amount of the rare earth element replacing solid-dissolved in the a site, the amount of the acceptor doped in the perovskite may be excessively large. In this case, the amount of oxygen defects may increase, and the lifetime characteristics may deteriorate. Further, when the ratio of the amount of the rare earth element substitutionally solid-dissolved in the a site to the amount of the rare earth element substitutionally solid-dissolved in the B site is close to 1, the amount of oxygen defects after firing is suppressed. Moreover, high reliability with an excellent balance between the insulation characteristic and the life characteristic can be achieved. Specifically, 0.75. ltoreq. (the amount of the rare earth element which is solid-dissolved in the A site by substitution)/(the amount of the rare earth element which is solid-dissolved in the B site by substitution) is 1.25 or less. The ratio is preferably 1.20 or less under the condition that the excessive doping of the donor is suppressed. More preferably, the ratio is 1.10 or less. Still more preferably, the ratio is 1.05 or less. The ratio is preferably 0.90 or more under the condition that the excessive doping of the acceptor is suppressed. More preferably, the ratio is 0.95 or more.

When the total amount of rare earth elements in the a site and the B site is too low, the amount of oxygen defects after firing may not be suppressed. Therefore, it is preferable that the total amount of the rare earth elements that are solid-soluble in the a site and the B site has a lower limit. For example, it is preferable that the total amount of the rare earth elements that are substitutionally solid-dissolved in the a site and the B site is 0.2 atm% or more. More preferably, the total amount is 0.3 atm% or more. atm% refers to ABO given ceramic material powder₃The amount of the B site element in (1) is a concentration at 100 atm%.

On the other hand, when the total amount of rare earth elements in the a site and the B site is too high, the tetragonal crystallinity of the crystal grains may be deteriorated. Also, defects such as a decrease in dielectric constant may occur. Therefore, it is preferable that the total amount of the rare earth elements that are solid-soluble in the a site and the B site by substitution has an upper limit. For example, it is preferable that the total amount of the rare earth elements that are substitutionally solid-dissolved in the a site and the B site is 1.0 atm% or less. More preferably, the total amount is 0.9 atm% or less.

As the rare earth element, Y (yttrium), La (lanthanum), Ce (cerium), Pr (praseodymium), Nd (neodymium), Pm (promethium), Sm (samarium), Eu (europium), Gd (gadolinium), Tb (terbium), Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Yb (ytterbium), or the like can be used. The ionic radius of the a site is different from the ionic radius of the B site. Preferably, the ionic radius of the rare earth element is between the ionic radius of the a site and the ionic radius of the B site for the purpose of achieving a good balance between the amount of the rare earth element substitutionally solid-dissolved in the a site and the amount of the rare earth element substitutionally solid-dissolved in the B site. For example, according to Table 1, preferably, when BaTiO is used₃In the case of perovskite, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Tm, Yb, etc. are substitutionally dissolved. The table 1 is set forth in "r.d. shatnnon, Acta crystallogr, a32,751 (1976)".

[ Table 1]

La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, etc., having relatively large ionic radii, tend to be substitutionally solid-soluble in the A site. On the other hand, Er, Tm, Yb and the like having a relatively small ionic radius tend to be substitutionally solid-soluble in the B site. Therefore, when substituting and dissolving La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, etc., it is preferable to also substitute and dissolve Er, Tm, Yb, etc.

When the element serving as a donor is substituted and dissolved in the B site, and is diluted thereinPerovskite (A) solid-dissolved in both A site and B site by substitution of earth element_mBO₃) When "m" in (1) is too small, the insulation property may be deteriorated. Therefore, it is preferable that "m" has a lower limit. Specifically, "m" is preferably 1.002 or more. On the other hand, if "m" is too large, the sintering characteristics may deteriorate. Thus, "m" has an upper limit. Specifically, "m" is preferably 1.010 or less.

Preferably, the average grain size of the ceramic, which is the main component of the dielectric layer 11, is 80nm to 300 nm. More preferably, the average crystal grain diameter is 80nm to 200 nm. When the average crystal grain size of the main component ceramic is small, the dielectric constant may be lowered and the required electrostatic capacitance may not be achieved. On the other hand, when the average crystal grain diameter is large, in the case where the thickness of the dielectric layer 11 is 1.0 μm or less, the lifetime characteristics may be deteriorated due to a decrease in the area of the boundary serving as a barrier to oxygen defect movement.

When the dielectric layer 11 is thick, high reliability can be achieved. However, in this case, the size of the laminated ceramic capacitor 100 may increase. Therefore, the embodiment of the present invention is effective for the laminated ceramic capacitor 100 having a small size. For example, the embodiment is effective for the multilayer ceramic capacitor 100 in which the thickness of the dielectric layer 11 is 1.0 μm or less. Further, when the thickness of the dielectric layer 11 is 0.4 μm or less, the laminated ceramic capacitor has a smaller size and higher reliability. Preferably, the thickness of the dielectric layer 11 is 0.2 μm or more in terms of securing insulation resistance.

Next, a description will be given of a method of manufacturing the laminated ceramic capacitor 100. Fig. 2 shows a method for manufacturing the laminated ceramic capacitor 100.

(production process of raw material powder) ceramic material powder was prepared. The main phase of the ceramic material powder has the general formula ABO₃The perovskite structure shown. The element substitution serving as a donor is solid-soluble in the B site. The rare earth element substitution is solid-soluble in both the A site and the B site. The ceramic material using the ceramic material powder is a main component of the dielectric layer 11. A number of methods for synthesizing ceramic material powders are known. For example, a solid phase method, a sol-Gel method, hydrothermal method, etc. (amount of the rare earth element that the substitution solid dissolves in the A site)/(amount of the rare earth element that the substitution solid dissolves in the B site) is 0.75 or more and 1.25 or less. As an example, a description will now be given of a solid phase synthesis method. Adding TiO into the mixture₂Powder and BaCO₃The powder is mixed with a dispersant and a solvent such as pure water. Thereby obtaining a slurry. Next, the solution in which the rare earth element is dissolved in acetic acid is neutralized. The resulting solution is mixed with the slurry, kneaded, and the slurry is dispersed in the solution. Alternatively, a powder of a molybdenum compound may be added to the slurry, and kneading and dispersion may be performed in a state where molybdenum is ionized or complexed. Kneading and dispersing are carried out for 20 hours to 30 hours. Next, the slurry was dried to obtain a raw material. The raw meal is subjected to a first calcination at a temperature of 800 to 1150 ℃. Obtaining the ceramic material powder.

Next, an additive compound may be added to the ceramic material powder according to the purpose. The additive compound may be an oxide of Mg (magnesium), Mn (manganese), V (vanadium), Cr (chromium), or an oxide of Co (cobalt), Ni, Li (lithium), B (boron), Na (sodium), K (potassium) and Si (silicon), or glass.

In an embodiment, a compound comprising an additive compound is mixed with a ceramic material powder. The resulting ceramic material powder with the additive compound is calcined at a temperature in the range of 820 ℃ to 1150 ℃. The ceramic material powder is then wet mixed with the additive compound. Thereafter, the ceramic material powder with the additive compound is dried and pulverized. Preparing the required ceramic material. For example, in terms of reducing the thickness of the dielectric layer 11, it is preferable that the average particle diameter of the ceramic material is 50nm to 150 nm. For example, the particle size of the produced ceramic material can be adjusted by pulverizing the produced ceramic material. Alternatively, the particle size can be adjusted by performing pulverization and classification treatment. Using this procedure, a ceramic material serving as a main component of the dielectric layer 11 is obtained.

(laminating process) next, a binder such as a polyvinyl butyral (PVB) resin, an organic solvent such as ethanol or toluene, and a plasticizer are added to the resulting ceramic material, and wet-mixed. With the resulting slurry, a bar-shaped dielectric green sheet having a thickness of 3 μm to 10 μm is coated on a substrate by, for example, a die coating method or a doctor blade method, and then dried.

Then, a pattern of the internal electrode layers 12 was provided on the surface of the dielectric green sheet by printing a metal conductive paste for forming the internal electrode layers by screen printing or gravure printing. The metal conductive paste includes an organic binder. Thus, an internal electrode layer pattern alternately drawn to the external electrode pairs is provided. As a co-material, ceramic particles are added to the metal conductive paste. The main component of the ceramic particles is not limited. Preferably, the main component of the ceramic particles is the same as the main component ceramic of the dielectric layer 11. For example, BaTiO with a uniform dispersion average particle diameter of 50nm or less₃。

Then, the dielectric green sheets on which the internal electrode layer patterns are printed are punched out to a predetermined size, a predetermined number (for example, 100-. Cover sheets to be the cover layers 13 are pressure-bonded to both upper and lower surfaces of the laminated dielectric green sheets. The resulting laminate is cut into a predetermined size (for example, 1.0mm × 0.5 mm).

In N₂In the atmosphere, the binder was removed from the resulting ceramic laminate. After that, a metal conductive paste including a metal filler, a co-material, a binder, a solvent, and the like, which is to be a base layer of the

external electrodes

20a and 20b, is applied from both end faces to a side face of the resulting ceramic laminate, and dried.

(firing Process) Next, N is performed at 250 to 500 ℃₂After removal of the binder in the atmosphere, the resulting shaped body is subjected to a temperature range of 1100 ℃ to 1300 ℃ with an oxygen partial pressure of 10^-5To 10^-8and (2) firing in a reducing atmosphere of atm for 10 minutes to 2 hours. Thereby, each compound constituting the dielectric green sheet is sintered, and crystal grains of each compound grow. In this way, a sintered body was obtained.

(reoxidation step) after this, N may be carried out at 600 ℃ to 1000 ℃₂The reoxidation step is performed in a gas atmosphere.

After the plating process, a metal layer, such as Cu, Ni, or Su, is coated on the base layers of the

external electrodes

20a and 20b through the plating process.

In the production method of the embodiment, the element serving as a donor is substitutionally dissolved in the B site of the perovskite structure in the ceramic material powder used in the material powder production process. Therefore, the amount of oxygen defects in the perovskite structure during firing is suppressed. Further, the life of the dielectric layer 11 is extended. Therefore, reliability can be improved. Also, the amount of oxygen defects after firing is suppressed because the rare earth element substitution solid dissolves in both the a site and the B site. Therefore, the insulating property is maintained, and the long-life property can be realized. Therefore, high reliability can be achieved. Further, when a relationship of 0.75. ltoreq. (amount of the rare earth element substitutionally solid-dissolved in the A site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) 1.25 or less is realized, the amount of oxygen defects after firing is suppressed. Also, high reliability with an excellent balance between the insulation characteristic and the life characteristic can be achieved.

The ratio is preferably 1.20 or less under the condition that the excessive doping of the donor is suppressed. More preferably, the ratio is 1.10 or less. Still more preferably, the ratio is 1.05 or less. The ratio is preferably 0.90 or more under the condition that the excessive doping of the acceptor is suppressed. More preferably, the ratio is 0.95 or more.

As the rare earth element, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, etc. can be used. The ionic radius of the a site is different from the ionic radius of the B site. Preferably, the ionic radius of the rare earth element is between the ionic radius of the a site and the ionic radius of the B site in terms of achieving an excellent balance of substitutional solid solution of the rare earth element between the a site and the B site. For example, according to Table 1, preferably, when BaTiO is used₃In the case of perovskite, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Tm, Yb, etc. are substitutionally dissolved.

Perovskite (A) when an element serving as a donor is substitutionally solid-dissolved in a B site, and in which a rare earth element is substitutionally solid-dissolved in both an A site and a B site_mBO₃) When "m" in (1) is too small, the insulation property may be deteriorated. Therefore, it is preferable that "m" has a lower limit. Specifically, "m" is preferably 1.002 or more. On the other hand, when "m" is too large, sintering characteristics may be deteriorated. Thus, "m" has an upper limit. Specifically, "m" is preferably 1.010 or less.

[ examples ]

The laminated ceramic capacitor according to the embodiment was manufactured, and characteristics were measured.

Preparation of BaTiO₃A ceramic material powder in which an element substitution solid solution serving as a donor is dissolved in a B site, and a rare earth element substitution solid solution is dissolved in both an a site and a B site. The average particle size was 150 nm. In any of examples 1 to 11 and comparative examples 1 to 9, when the amount of Ti was set to 100 atm%, Mo in an amount of 0.2 atm% was substitutionally dissolved in the B site.

In examples 1 and 2, ceramic material powders in which Ho, which was 0.2 atm% of substitutional solid solution, was used as a rare earth element. Thereafter, Ho is added in an amount corresponding to 0.8 atm% Ho₂O₃. In examples 3 to 7, ceramic material powders in which Ho as a rare earth element was substitutionally solid-solubilized at 0.5 atm% were used. Thereafter, Ho is added in an amount corresponding to 0.5 atm% Ho₂O₃. In example 8, a ceramic material powder in which 0.25 atm% Gd and 0.25 atm% Yb were substitutionally solid-dissolved as rare earth elements was used. Thereafter, Gd is added in an amount corresponding to 0.25 atm% Gd₂O₃And Yb in an amount corresponding to 0.25 atm% Yb₂O₃. In examples 9 to 11, ceramic material powders in which Ho as a rare earth element was substitutionally solid-solubilized at 1.0 atm% were used. In comparative example 1, the rare earth element is solid-dissolved in the ceramic material powder without being substituted. Adding Ho in an amount corresponding to 1.0 atm% Ho₂O₃. In comparative example 2, a ceramic material powder in which Ho in 0.2 atm% of substitutional solid solution was used as a rare earth element. Thereafter, Ho is added in an amount corresponding to 0.8 atm% Ho₂O₃. In comparative examples 3 to 5, the solid solution was replaced with0.5 atm% Ho as a ceramic material powder of a rare earth element. Thereafter, Ho is added in an amount corresponding to 0.5 atm% Ho₂O₃. In comparative example 6, a ceramic material powder in which 0.2 atm% Gd and 0.3 atm% Yb were substitutionally solid-dissolved as rare earth elements was used. Thereafter, Gd is added in an amount corresponding to 0.2 atm% Gd₂O₃And Yb in an amount corresponding to 0.3 atm% Yb₂O₃. In comparative example 7, a ceramic material powder in which 0.3 atm% Gd and 0.2 atm% Yb were substitutionally solid-dissolved as rare earth elements was used. Thereafter, Gd is added in an amount corresponding to 0.3 atm% Gd₂O₃And Yb in an amount corresponding to 0.2 atm% Yb₂O₃. In comparative examples 8 and 9, ceramic material powders in which Ho of 1.0 atm% of solid solution was substitutionally dissolved as a rare earth element were used. In this paragraph, "atm%" refers to ABO of the ceramic material powder₃The amount of the B site of (a) is a concentration at 100 atm%.

In example 1, (amount of the rare earth element substitutionally solid-dissolved in the a site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) was 0.95. In example 2, (amount of the rare earth element substitutionally solid-dissolved in the a site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) was 1.10. In example 3, (amount of the rare earth element substitutionally solid-dissolved in the a site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) was 0.75. In example 4, (amount of the rare earth element substitutionally solid-dissolved in the a site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) was 0.95. In example 5, (amount of the rare earth element substitutionally solid-dissolved in the a site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) was 1.00. In example 6, (amount of the rare earth element substitutionally solid-dissolved in the a site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) was 1.05. In example 7, (amount of the rare earth element substitutionally solid-dissolved in the a site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) was 1.25. In example 8, (amount of the rare earth element substitutionally solid-dissolved in the a site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) was 1.10. In example 9, (amount of the rare earth element substitutionally solid-dissolved in the a site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) was 0.75. In example 10, (amount of the rare earth element substitutionally solid-dissolved in the a site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) was 1.03. In example 11, (amount of the rare earth element substitutionally solid-dissolved in the a site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) was 1.20. In comparative example 2, (amount of the rare earth element substitutionally solid-dissolved in the a site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) was 1.32. In comparative example 3, (amount of the rare earth element substitutionally solid-dissolved in the a site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) was 0.50. In comparative example 4, (amount of the rare earth element in which the substitution solid is dissolved in the a site)/(amount of the rare earth element in which the substitution solid is dissolved in the B site) is 1.35. In comparative example 5, (amount of the rare earth element substitutionally solid-dissolved in the a site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) was 1.50. In comparative example 6, (amount of the rare earth element substitutionally solid-dissolved in the a site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) was 0.70. In comparative example 7, (amount of the rare earth element substitutionally solid-dissolved in the a site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) was 1.50. In comparative example 8, (amount of the rare earth element substitutionally solid-dissolved in the a site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) was 0.66. In comparative example 9, (amount of the rare earth element substitutionally solid-dissolved in the a site)/(amount of the rare earth element substitutionally solid-dissolved in the B site) was 1.30.

As the amount of the element replacing the solid solution, the amount of the element replacing the solid solution was measured by subjecting the ceramic material powder to an etching treatment using Ar ions and deforming the ceramic material powder into a hemispherical shape to obtain a treated sample, and measuring the treated sample by energy dispersive fluorescence X-ray spectroscopy (EDS) using TEM (transmission electron microscope). For (amount of rare earth element that the substitution solid dissolves in the a site)/(amount of rare earth element that the substitution solid dissolves in the B site), the treated sample was measured using a high-angle toroidal dark-field scanning transmission electron microscope.

In any of examples 1 to 11 and comparative examples 1 to 9, Mo is solid-dissolved by substitution in the B site, and the rare earth element is solid-dissolved by substitution in both the A site and the B site, A_mBO₃"m" in (1) is 1.002.

AsAdditive, adding 1.0 mol% MgO into ceramic material powder. As additives, 0.05 mol% MnO and 0.05 mol% V were added to the ceramic material powder₂O₅. As a sintering aid, 1.0 mol% SiO is added to the ceramic material powder₂And 1.0 mol% BaCO₃. In this case, "mol%" is defined as ABO in the ceramic material powder₃The amount of (B) is a value at 100 mol%.

Additives and sintering aids are added to the ceramic material powder. The resulting ceramic material powder was thoroughly wet-mixed and pulverized with a ball mill. Thereby, a ceramic material is obtained. An organic binder and a solvent are added to the ceramic material. A dielectric green sheet was produced by a doctor blade method. The thickness of the dielectric green sheet was 0.8. mu.m. The organic binder is polyvinyl butyral (PVB) resin or the like. The solvent is ethanol, toluene, etc. And adding a plasticizer, etc. Next, a conductive paste for forming the internal electrode layers was formed by a planetary ball mill. The conductive paste includes a metal (Ni) powder as a main component of the internal electrode layer 12, a co-material (barium titanate), a binder (ethyl cellulose), a solvent, and an auxiliary agent as needed.

A conductive paste for forming the internal electrode layers was screen-printed on the dielectric green sheet. 250 dielectric green sheets on which a conductive paste for forming internal electrode layers was printed were stacked, and cover sheets were stacked on both upper and lower surfaces of the stacked dielectric green sheets. Thereafter, a ceramic laminate was obtained by hot pressing. The ceramic laminated body is cut into a predetermined size. In N₂The binder is removed from the ceramic laminate in the atmosphere. After that, a metal paste including a metal filler whose main component is Ni, a co-material, a binder, and a solvent is applied from both end faces to the side faces of the ceramic laminate, and dried. Thereafter, the resulting laminate is fired together with the metal paste in a reducing atmosphere at a temperature ranging from 1100 ℃ to 1300 ℃ for 10 minutes to 2 hours. Thereby, a sintered body was formed.

The resulting sintered body had a length of 0.6mm, a width of 0.3mm and a height of 0.3 mm. In N₂The sintered body was subjected to reoxidation treatment at 800 ℃ in a gas atmosphere. Thereafter, the plating process is performed to form a surface of the base layer of the external electrodes 20a and 20bA Cu-plating layer, a Ni-plating layer and a Sn-plating layer are formed on the surface. The multilayer ceramic capacitor 100 is obtained.

(analysis) for each of examples 1 to 11 and comparative examples 1 to 9, 20 samples were produced. The life characteristics of each sample were tested. For each of examples 1 to 11 and comparative examples 1 to 9, the average life was measured. In the lifetime characteristic test, 10V DC voltage was applied to each sample at 125 ℃. The leakage current was measured by an ammeter. The time until each sample broke was the lifetime value. Insulation resistance testing was performed on each sample. For each of examples 1 to 11 and comparative examples 1 to 9, the average insulation resistance was measured. In the insulation resistance test, 10V dc voltage was applied to each sample at room temperature. The insulation resistance was measured from the current value after 60 seconds.

When the average life is 100min or less, the life characteristic is determined to be NG. When the insulation resistance is 10M Ω or less, the insulation characteristic is determined to be NG. When at least one of the lifetime characteristic and the insulation characteristic is determined to be NG, the reliability is determined to be NG. Table 2 shows the results.

[ Table 2]

In comparative example 1, both the lifetime characteristic and the insulation characteristic were determined to be NG. This is considered to be because ceramic material powder which does not displace the solid-solution rare earth element is used and the solid-solution rare earth element is not sufficiently displaced. In comparative examples 2, 4, 5, 7 and 9, the lifetime characteristic was determined to be OK, but the insulation characteristic was determined to be NG. It is considered that this is because (the amount of the rare earth element substitutionally solid-dissolved in the A site)/(the amount of the rare earth element substitutionally solid-dissolved in the B site) is more than 1.25. In comparative examples 3, 6 and 8, the insulation characteristic was determined as OK, but the life characteristic was determined as NG. This is considered to be because (the amount of the rare earth element substitutionally solid-dissolved in the A site)/(the amount of the rare earth element substitutionally solid-dissolved in the B site) is less than 0.75.

On the other hand, in any of examples 1 to 11, both the lifetime characteristic and the insulation characteristic were determined as OK. It is considered that this is because the element substitution solid that serves as a donor is dissolved in the B site, the rare earth element substitution solid is dissolved in both the a site and the B site, and (the amount of the rare earth element that the substitution solid is dissolved in the a site)/(the amount of the rare earth element that the substitution solid is dissolved in the B site) is 0.75 or more and 1.25 or less.

Both the insulation resistance and the lifetime characteristics of examples 4 and 5 are superior to those of example 3. This is considered to be because (the amount of the rare earth element substitutionally solid-dissolved in the A site)/(the amount of the rare earth element substitutionally solid-dissolved in the B site) is 0.95 or more. The insulation resistance and the lifetime characteristics of example 2 are superior to those of example 7, which is considered to be because (the amount of the rare earth element substitutionally solid-dissolved in the a site)/(the amount of the rare earth element substitutionally solid-dissolved in the B site) is 1.10 or less. Both the insulation resistance and the lifetime characteristics of examples 5 and 6 are superior to those of example 2. This is considered to be because (the amount of the rare earth element that the substitution solid dissolves in the a site)/(the amount of the rare earth element that the substitution solid dissolves in the B site) is 1.05 or less. The life characteristics of example 10 were superior to those of example 9. This is considered to be because (the amount of the rare earth element substitutionally solid-dissolved in the a site)/(the amount of the rare earth element substitutionally solid-dissolved in the B site) is 0.95 or more. The life characteristics of example 10 were superior to those of example 11. This is considered to be because (the amount of the rare earth element that the substitution solid dissolves in the a site)/(the amount of the rare earth element that the substitution solid dissolves in the B site) is 1.05 or less.

Although the embodiments of the present invention have been described in detail, it should be understood that various changes, substitutions, and alterations can be made hereto without departing from the spirit and scope of the invention.

Claims

1. A laminated ceramic capacitor, comprising:

a stacked body in which each of a plurality of dielectric layers and each of a plurality of internal electrode layers are alternately stacked,

wherein the main component of the dielectric layer is a ceramic material,

wherein the pottery isThe main phase of the porcelain material has a general formula ABO₃The perovskite structure shown in (A) is,

wherein the B site of the ceramic material comprises an element that acts as a donor,

wherein the A site and the B site of the ceramic material comprise a rare earth element,

wherein the ratio of the amount of the rare earth element substitutionally solid-dissolved in the A site to the amount of the rare earth element substitutionally solid-dissolved in the B site is 0.75 or more and 1.25 or less,

wherein, assuming that the amount of an element which is a main component of the B site is 100 atm%, the amount of an element which serves as a donor and is solid-dissolved in the B site is 0.05 atm% or more and 0.3 atm% or less.

2. The laminated ceramic capacitor of claim 1, wherein the ceramic material comprises Ba and Ti.

3. The laminated ceramic capacitor according to claim 2, wherein the element serving as a donor comprises Mo.

4. The laminated ceramic capacitor of claim 2, wherein the rare earth element includes at least one of Tb, Dy, Ho, and Y.

5. The laminated ceramic capacitor of claim 2, wherein the rare earth element in the A site includes at least one of La, Ce, Pr, Nd, Pm, Sm, Eu, and Gd,

wherein the rare earth element in the B site comprises at least one of Er, Tm, and Yb.

6. The laminated ceramic capacitor according to claim 1, wherein the dielectric layer has a thickness of 0.4 μm or less in the lamination direction.

7. The laminated ceramic capacitor according to any one of claims 1 to 6, wherein a ratio of an amount of the rare earth element substitutionally solid-dissolved in the A site to an amount of the rare earth element substitutionally solid-dissolved in the B site is 0.95 or more and 1.05 or less.

8. A ceramic material powder, comprising:

a main phase having the formula ABO₃The perovskite structure shown in (A) is,

an element serving as a donor in a B site of the perovskite structure, and

a rare earth element in the A site and the B site of the perovskite structure,

9. The ceramic material powder of claim 8, further comprising Ba and Ti.

10. The ceramic material powder according to claim 9, wherein the element that serves as a donor comprises Mo.

11. The ceramic material powder of claim 9, wherein the rare earth element comprises at least one of Tb, Dy, Ho, and Y.

12. The ceramic material powder according to claim 9, wherein the rare earth element in the A site includes at least one of La, Ce, Pr, Nd, Pm, Sm, Eu, and Gd,

13. The ceramic material powder according to any one of claims 8 to 12, wherein a ratio of an amount of the rare earth element substitutionally solid-dissolved in the a site to an amount of the rare earth element substitutionally solid-dissolved in the B site is 0.95 or more and 1.05 or less.