Dielectric composition, multilayer ceramic electronic component, method for manufacturing dielectric composition, and method for manufacturing multilayer ceramic electronic component

Abstract

To provide a dielectric composition, a multilayer ceramic electronic component, a manufacturing method of a dielectric composition, and a manufacturing method of a multilayer ceramic electronic component, capable of achieving both a long life and the excellent temperature characteristics of capacity.SOLUTION: A dielectric composition includes: a main component containing barium titanate; a first additive containing zirconium in an amount of 2 at% or more and 10 at% or less with respect to titanium of the barium titanate; a second additive containing 0.2 at% or more and 3.5 at% or less of europium with respect to titanium of the barium titanate, and a content of a rear earth element other than the europium is less than that of the europium; a third additive containing 0.5 at% or more and 4.5 at% or less of manganese with respect to titanium of the barium titanate; and a fourth additive containing at least one of strontium and calcium in an amount of 0.1 at% or more and 3 at% or less with respect to titanium in the barium titanate.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a dielectric composition, a multilayer ceramic electronic component, a method for producing a dielectric composition, and a method for producing a multilayer ceramic electronic component. [Background technology]

[0002] Multilayer ceramic capacitors are used to remove noise in high-frequency communication systems, such as mobile phones. Multilayer ceramic capacitors are also used in electronic circuits that affect human life, such as in-vehicle electronic control devices. High reliability is required for multilayer ceramic capacitors, and techniques for improving reliability have been disclosed (see, for example, Patent Documents 1 to 5). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2017-114751 [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-90458 [Patent Document 3] Japanese Patent Application Publication No. 2019-131438 [Patent Document 4] Japanese Patent Application Laid-Open No. 2016-169130 [Patent Document 5] Japanese Patent Application Laid-Open No. 2015-187969 Summary of the Invention [Problem to be solved by the invention]

[0004] For the dielectric of multilayer ceramic capacitors, sintered bodies with a core-shell structure have been used, in which a barium titanate core is surrounded by a shell containing various additives in solid solution. This is because it provides excellent capacitance-temperature characteristics and allows the production of materials with a stable microstructure even during the sintering process. Magnesium (Mg) is a typical additive that makes up the shell. However, magnesium is a simple acceptor with no valence fluctuation, and because it is electrically neutral, it generates oxygen vacancies, which are known to have a negative impact on the reliability of multilayer ceramic capacitors. This has led to the problem that the reliability is not high enough for high-reliability applications.

[0005] Next, multilayer ceramic capacitors that can be used at high temperatures up to 150°C are required for high-reliability applications. However, barium titanate, the main component of the dielectric layer, has a Curie point of approximately 125°C, and its capacitance decreases significantly at temperatures above that point. Therefore, without special ingenuity, it is impossible to meet the EIA standard for temperature characteristics X8R (the rate of capacitance change from -55°C to 150°C must be within ±15% of the capacitance at 25°C). One solution is to add ytterbium (Yb) to the dielectric layer to shift the Curie point toward higher temperatures and thereby meet the X8R standard. However, ytterbium acts as an acceptor, and like magnesium, this does not provide sufficient reliability for high-reliability applications. Another approach is to mix BaTi2O5 (470°C), which has a high Curie point, with BaTiO3, but BaTi2O5 has a low dielectric constant at room temperature and therefore does not achieve high capacitance.

[0006] The present invention has been made in view of the above-mentioned problems, and has an object to provide a dielectric composition, a multilayer ceramic electronic component, a method for manufacturing a dielectric composition, and a method for manufacturing a multilayer ceramic electronic component, which are capable of achieving both a long life and excellent capacitance-temperature characteristics. [Means for solving the problem]

[0007] The dielectric composition of the present invention comprises a main component containing barium titanate, a first additive containing zirconium in an amount of 2 at% to 10 at% relative to the titanium in the barium titanate, a second additive containing europium in an amount of 0.2 at% to 3.5 at% relative to the titanium in the barium titanate and containing fewer rare earth elements other than europium than europium, a third additive containing manganese in an amount of 0.5 at% to 4.5 at% relative to the titanium in the barium titanate, and a fourth additive containing at least one of strontium and calcium in an amount of 0.1 at% to 3 at% relative to the titanium in the barium titanate.

[0008] The dielectric composition may contain dielectric crystals having a core portion in which europium is dissolved and a shell portion that covers the core portion and has a higher zirconium concentration than the core portion.

[0009] In the above dielectric composition, the second additive may contain divalent europium and trivalent europium, and the divalent europium may account for 21% or more and 80% or less of the total europium contained in the second additive.

[0010] In the dielectric composition, the first additive may contain zirconium in an amount of 2 at % or more and 8 at % or less relative to the titanium in the barium titanate.

[0011] In the dielectric composition, the second additive may contain europium in an amount of 0.5 at % or more and 3 at % or less relative to the titanium in the barium titanate.

[0012] In the dielectric composition, the third additive may contain manganese in an amount of 0.5 at % or more and 3 at % or less relative to the titanium in the barium titanate.

[0013] In the above dielectric composition, the fourth additive may contain at least one of strontium and calcium in an amount of 0.1 at % or more and 1 at % or less relative to the titanium in the barium titanate.

[0014] The multilayer ceramic electronic component according to the present invention includes a plurality of dielectric layers each including a main component containing barium titanate, a first additive containing zirconium at 2 at% to 10 at% relative to the titanium in the barium titanate, a second additive containing europium at 0.2 at% to 3.5 at% relative to the titanium in the barium titanate and containing fewer rare earth elements other than europium than europium, a third additive containing manganese at 0.5 at% to 4.5 at% relative to the titanium in the barium titanate, and a fourth additive containing at least one of strontium and calcium at 0.1 at% to 3 at% relative to the titanium in the barium titanate, a plurality of internal electrode layers stacked with each of the plurality of dielectric layers interposed therebetween, and external electrodes electrically connected to the plurality of internal electrodes.

[0015] In the above-described multilayer ceramic electronic component, the plurality of dielectric layers may include dielectric crystals having a core portion in which europium is dissolved and a shell portion that covers the core portion and has a higher zirconium concentration than the core portion.

[0016] In the above-described multilayer ceramic electronic component, the second additive may contain divalent europium and trivalent europium, and the divalent europium may account for 21% or more and 80% or less of the total europium contained in the second additive.

[0017] In the above-described monolithic ceramic electronic component, the first additive may contain zirconium in an amount of 2 at % or more and 8 at % or less relative to the titanium in the barium titanate.

[0018] In the above-described monolithic ceramic electronic component, the second additive may contain europium in an amount of 0.5 at % or more and 3 at % or less relative to the titanium in the barium titanate.

[0019] In the above-described monolithic ceramic electronic component, the third additive may contain manganese in an amount of 0.5 at % or more and 3 at % or less relative to the titanium in the barium titanate.

[0020] In the above-described monolithic ceramic electronic component, the fourth additive may contain at least one of strontium and calcium in an amount of 0.1 at % or more and 1 at % or less relative to the titanium in the barium titanate.

[0021] The multilayer ceramic electronic component may satisfy the X8R characteristics.

[0022] A method for producing a dielectric composition according to the present invention includes the steps of: forming a ceramic green sheet containing a main component containing barium titanate; a first additive containing zirconium at 2 at% to 10 at% relative to the titanium in the barium titanate; a second additive containing europium at 0.2 at% to 3.5 at% relative to the titanium in the barium titanate and containing fewer rare earth elements other than europium than europium; a third additive containing manganese at 0.5 at% to 4.5 at% relative to the titanium in the barium titanate; and a fourth additive containing at least one of strontium and calcium at 0.1 at% to 3 at% relative to the titanium in the barium titanate; and firing the ceramic green sheet at a temperature rise rate of 5,000°C / h to 10,000°C / h.

[0023] A method for producing a multilayer ceramic electronic component according to the present invention includes the following steps: a coating step of forming ceramic green sheets containing a main component including barium titanate; a first additive containing zirconium at 2 at% to 10 at% relative to the titanium in the barium titanate; a second additive containing europium at 0.2 at% to 3.5 at% relative to the titanium in the barium titanate, with the amount of rare earth elements other than europium being less than that of europium; a third additive containing manganese at 0.5 at% to 4.5 at% relative to the titanium in the barium titanate; and a fourth additive containing at least one of strontium and calcium at 0.1 at% to 3 at% relative to the titanium in the barium titanate; an internal electrode forming step of forming internal electrode patterns on the ceramic green sheets; a pressure-bonding step of stacking the ceramic green sheets on which the internal electrode patterns have been formed; and a firing step of firing the stacked ceramic green sheets at a temperature rise rate of 5,000°C / h to 10,000°C / h to form a plurality of dielectric layers and a plurality of internal electrodes.

[0024] The method for manufacturing the multilayer ceramic electronic component may further include a reoxidation step of heat-treating the plurality of dielectric layers and the plurality of internal electrodes after the firing step. [Effects of the Invention]

[0025] According to the present invention, it is possible to provide a dielectric composition, a multilayer ceramic electronic component, a method for manufacturing a dielectric composition, and a method for manufacturing a multilayer ceramic electronic component that can achieve both a long life and excellent capacitance-temperature characteristics. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 2 is a partial cross-sectional perspective view of a multilayer ceramic capacitor. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 3] FIG. 2 is a cross-sectional view taken along line BB in FIG. [Figure 4]FIG. 2(a) is a diagram illustrating an example of a core-shell particle, and FIG. 2(b) is a schematic cross-sectional view of a dielectric layer. [Figure 5] 1A to 1C are diagrams illustrating a flow of a method for manufacturing a multilayer ceramic capacitor. [Figure 6] 3 is a schematic SEM image of a cross section of the dielectric layers and internal electrode layers in the capacitance region in Example 1. FIG. [Figure 7] FIG. 1 is a schematic diagram of a TEM image of a dielectric layer in a capacitance region. [Figure 8] (a) shows the measurement results of TEM-EDS analysis of the shell part, and (b) shows the measurement results of TEM-EDS analysis of the core part. [Figure 9] FIG. 12 is a schematic SEM image of a cross section of the dielectric layers and internal electrode layers in the capacitance region of Comparative Example 11. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, embodiments will be described with reference to the drawings.

[0028] (Embodiment) FIG. 1 is a partial cross-sectional perspective view of a multilayer ceramic capacitor 100 according to an embodiment. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. FIG. 3 is a cross-sectional view taken along line BB in FIG. 1. As illustrated in FIGS. 1 to 3, the multilayer ceramic capacitor 100 includes a laminated chip 10 having a substantially rectangular parallelepiped shape and external electrodes 20a, 20b provided on two opposing end faces of the laminated chip 10. Of the four faces of the laminated chip 10 other than the two end faces, the two faces other than the top and bottom faces in the stacking direction are referred to as side faces. The external electrodes 20a, 20b extend on the top, bottom and two side faces of the laminated chip 10 in the stacking direction. However, the external electrodes 20a, 20b are spaced apart from each other.

[0029] The multilayer chip 10 has a configuration in which dielectric layers 11 containing a ceramic material that functions as a dielectric and internal electrode layers 12 containing a base metal material are alternately stacked. The edges of each internal electrode layer 12 are alternately exposed at the end face of the multilayer chip 10 where the external electrode 20a is provided and the end face where the external electrode 20b is provided. As a result, each internal electrode layer 12 is alternately electrically connected to the external electrode 20a and the external electrode 20b. As a result, the multilayer ceramic capacitor 100 has a configuration in which multiple dielectric layers 11 are stacked with the internal electrode layers 12 interposed therebetween. In addition, in the laminate of the dielectric layers 11 and the internal electrode layers 12, the internal electrode layer 12 is arranged as the outermost layer in the stacking direction, and the upper and lower surfaces of the laminate are covered with cover layers 13. The cover layers 13 are primarily composed of a ceramic material. For example, the cover layers 13 may have the same or different composition as the dielectric layers 11. Note that the configuration is not limited to those shown in FIGS. 1 to 3, as long as the internal electrode layers 12 are exposed on two different surfaces and are electrically connected to different external electrodes.

[0030] The size of the multilayer ceramic capacitor 100 is, for example, 0.25 mm in length, 0.125 mm in width, and 0.125 mm in height, or 0.4 mm in length, 0.2 mm in width, and 0.2 mm in height, or 0.6 mm in length, 0.3 mm in width, and 0.3 mm in height, or 1.0 mm in length, 0.5 mm in width, and 0.5 mm in height, or 3.2 mm in length, 1.6 mm in width, and 1.6 mm in height, or 4.5 mm in length, 3.2 mm in width, and 2.5 mm in height, but is not limited to these sizes.

[0031] The internal electrode layers 12 are mainly composed of base metals such as Ni (nickel), Cu (copper), and Sn (tin). Noble metals such as Pt (platinum), Pd (palladium), Ag (silver), and Au (gold), or alloys containing these metals, may also be used as the internal electrode layers 12. The thickness of the internal electrode layers 12 is, for example, 0.1 μm to 3 μm, 0.1 μm to 1 μm, or 0.1 μm to 0.5 μm.

[0032] The dielectric layer 11 is a dielectric composition, and is mainly composed of, for example, a ceramic material having a perovskite structure represented by the general formula ABO3. Note that the perovskite structure is formed by an ABO3 composition that deviates from the stoichiometric composition. 3-α In this embodiment, barium titanate (BaTiO3) is used as the ceramic material. The thickness of the dielectric layer 11 is, for example, 0.2 μm to 10 μm, 0.2 μm to 5 μm, or 0.2 μm to 2 μm.

[0033] 2, the region where the internal electrode layer 12 connected to the external electrode 20a and the internal electrode layer 12 connected to the external electrode 20b face each other is a region where capacitance is generated in the multilayer ceramic capacitor 100. Therefore, this region where capacitance is generated is referred to as a capacitance region 14. In other words, the capacitance region 14 is a region where adjacent internal electrode layers 12 connected to different external electrodes face each other.

[0034] The region where the internal electrode layers 12 connected to the external electrode 20a face each other without an internal electrode layer 12 connected to the external electrode 20b interposed therebetween is called the end margin 15. The region where the internal electrode layers 12 connected to the external electrode 20b face each other without an internal electrode layer 12 connected to the external electrode 20a interposed therebetween is also the end margin 15. In other words, the end margin 15 is the region where the internal electrode layers 12 connected to the same external electrode face each other without an internal electrode layer 12 connected to a different external electrode interposed therebetween. The end margin 15 is a region where no capacitance is generated.

[0035] 3, in the laminated chip 10, the regions extending from the two side surfaces of the laminated chip 10 to the internal electrode layers 12 are referred to as side margins 16. In other words, the side margins 16 are regions provided so as to cover the ends of the multiple internal electrode layers 12 stacked in the above-mentioned laminated structure, which extend to the two side surfaces. The side margins 16 are also regions that do not generate electrical capacitance.

[0036] The dielectric layer 11 of the capacitance region 14 is mainly composed of barium titanate and contains a first additive containing zirconium (Zr), a second additive containing europium (Eu), a third additive containing manganese (Mn), and a fourth additive containing at least one of strontium or calcium.

[0037] In the capacitance region 14 of such a multilayer ceramic capacitor 100, if at least a portion of the barium titanate crystal grains (dielectric crystals) contained in the dielectric layer 11 have a core-shell structure, the dielectric layer 11 in the capacitance region 14 will have a high dielectric constant, excellent temperature characteristics, and a stable microstructure.

[0038] A typical additive that constitutes the shell is magnesium. However, magnesium is a simple acceptor whose valence does not change, and it dissolves in the barium titanate of the dielectric layer 11, generating oxygen defects, which may limit reliability.

[0039] (Regarding the first additive) Therefore, in this embodiment, the dielectric layer 11 of the capacitance region 14 contains the first additive, so that at least some of the barium titanate crystal particles contained in the dielectric layer 11 have a core-shell structure with a core portion mainly composed of barium titanate and a zirconium (Zr) diffusion layer as a shell portion. The shell portion is mainly composed of barium titanate.

[0040] As illustrated in FIG. 4( a), the core-shell particle 30 includes a substantially spherical core portion 31 and a shell portion 32 that surrounds and covers the core portion 31. The core portion 31 is a crystalline portion in which the additive compound is not dissolved or in which the amount of the additive compound dissolved is small. The shell portion 32 is a crystalline portion in which the additive compound is dissolved and has a higher additive compound concentration than the additive compound concentration in the core portion 31. In this embodiment, the zirconium concentration in the shell portion 32 is higher than the zirconium concentration in the core portion 31. Alternatively, zirconium is diffused in the shell portion 32, but not in the core portion 31.

[0041] Fig. 4(b) is a schematic cross-sectional view of the dielectric layer 11. As illustrated in Fig. 4(b), the dielectric layer 11 includes a plurality of crystal grains 17 of a main component ceramic. At least some of these crystal grains 17 are the core-shell particles 30 described in Fig. 4(a). By covering the core portion 31 with a shell portion 32 with a high zirconium concentration and high resistance to reduction, a highly reliable material can be obtained that has a stable structure while maintaining a high dielectric constant.

[0042] Furthermore, when zirconium diffuses into barium titanate, it lowers the Curie temperature of the barium titanate. Therefore, if the zirconium diffusion layer is made thicker than necessary, the capacitance change rate at high temperatures increases, potentially causing the multilayer ceramic capacitor 100 to fail to meet the X8R characteristics. Generally, zirconium dissolves in barium titanate, causing rapid grain growth. Therefore, it is difficult to achieve the X8R characteristics by limiting the thickness of the diffusion layer and suppressing grain growth. For example, setting the temperature rise rate during the sintering process to approximately 10°C / h excessively promotes rare earth diffusion, resulting in the formation of fully dissolved particles. In this case, the progress of the solid solution of zirconium and rare earth elements results in a long lifespan, but the dielectric constant is low, sintering stability is reduced, and the capacitance temperature characteristics tend to be poor. In this embodiment, the zirconium diffusion distance is limited, and the zirconium concentration is higher in the shell portion 32 than in the core portion 31, allowing the multilayer ceramic capacitor 100 to meet the X8R characteristics.

[0043] If the zirconium content in the dielectric layer 11 of the capacitance region 14 is low, the core-shell structure having a core with a low zirconium concentration and a shell with a high zirconium concentration cannot be maintained, resulting in localized abnormal growth, which may result in a long life and an inability to obtain X8R characteristics. Therefore, in this embodiment, a lower limit is set for the zirconium content relative to titanium in barium titanate, the main component of the dielectric layer 11 (zirconium content (at %) when titanium is 100 at %). Specifically, the zirconium content relative to titanium is set to 2 at % or more. In this case, the grain size of the crystal grains 17 becomes substantially uniform, and a stable core-shell structure with an element distribution in which a high concentration of Zr is located in the shell portion 32 can be formed. The zirconium content relative to titanium is preferably 2 at % or more, and more preferably 4 at % or more.

[0044] On the other hand, if the amount of zirconium in the dielectric layer 11 of the capacitance region 14 is large, the relative dielectric constant of the dielectric layer 11 will be low (for example, 1500 or less), and the X8R characteristics may not be satisfied. Therefore, in this embodiment, an upper limit is set on the amount of zirconium relative to titanium. Specifically, the amount of zirconium relative to titanium in the dielectric layer 11 of the capacitance region 14 is set to 10 at% or less. This makes it possible to obtain a sufficient relative dielectric constant. The amount of zirconium relative to titanium is preferably 8 at% or less, and more preferably 6 at% or less.

[0045] (Regarding the second additive) However, adding zirconium to the dielectric layer 11 expands the lattice constant of the barium titanate crystal, and rare earth elements such as holmium (Ho), dysprosium (Dy), and yttrium (Y), which are essential for the lifespan, are dissolved in greater amounts in the Ti site than in the Ba site, resulting in an excess of acceptors, and therefore limiting the effect of improving the lifespan.

[0046] Therefore, the inventors investigated rare earth elements with large ionic radii that easily form a solid solution at the Ba site of barium titanate, and found that adding europium (Eu) improves the lifespan by about one order of magnitude compared to rare earth elements such as holmium, dysprosium, and yttrium. The reason why adding europium improves the lifespan is not fully understood, but it is thought that europium is stable in its divalent and trivalent states, fluctuates between divalent and trivalent states, and has the largest ionic radius among the rare earth element ions that are stable in their divalent state, so it selectively forms a solid solution at the Ba site. Rare earth elements other than europium are stable in their trivalent state but unstable in their divalent state.

[0047] Table 1 shows the ionic radii of the six-coordinate rare earth elements. The source of Table 1 is "RD Shannon, Acta Crystallogr., A32, 751 (1976)." [Table 1]

[0048] Europium also dissolves more in the shell portion 32 than in the core portion 31. Therefore, the europium concentration in the shell portion 32 is higher than the europium concentration in the core portion 31.

[0049] In the dielectric layer 11 of the capacitance region 14, if the amount of europium relative to titanium in barium titanate, which is the main component of the dielectric layer 11 (the amount of europium (at %) when titanium is 100 at %), is too small, a sufficiently long life may not be obtained. Therefore, in this embodiment, a lower limit is set for the amount of europium relative to titanium. Specifically, in the dielectric layer 11 of the capacitance region 14, the amount of europium relative to titanium is set to 0.2 at % or more. The amount of europium relative to titanium is preferably 0.5 at % or more, and more preferably 1 at % or more.

[0050] On the other hand, if the amount of europium relative to titanium in the dielectric layer 11 of the capacitance region 14 is too large, the dielectric layer 11 may become semiconductive, and a long life may not be obtained. Therefore, in this embodiment, an upper limit is set on the amount of europium relative to titanium. Specifically, the amount of europium relative to titanium in the dielectric layer 11 of the capacitance region 14 is set to 3.5 at% or less. The amount of europium relative to titanium is preferably 3 at% or less, and more preferably 2 at% or less.

[0051] If the amount of divalent europium in the europium added to the dielectric layer 11 of the capacitance region 14 is small, a sufficiently long life may not be obtained. Therefore, it is preferable to set a lower limit for the amount of divalent europium in the dielectric layer 11 of the capacitance region 14. For example, in the dielectric layer 11 of the capacitance region 14, the divalent europium content is preferably 21% or more of the total europium, and more preferably 26% or more.

[0052] In order to increase the proportion of divalent europium, it is necessary to reduce a large amount of trivalent europium. However, during the annealing process for reducing a large amount of trivalent europium to divalent europium, grain growth may occur in the dielectric layer 11. Grain growth may shorten the life of the dielectric layer 11. Therefore, if grain growth occurs in the dielectric layer 11, the life-reducing effect of the grain growth may offset the life-improving effect of the europium valence, and the grain growth may cause the internal electrode layer 12 to lose its structure, resulting in a short circuit. Therefore, it is preferable to set an upper limit on the amount of divalent europium in the dielectric layer 11 of the capacitance region 14. For example, in the dielectric layer 11 of the capacitance region 14, the divalent europium content is preferably 80% or less of the total europium, more preferably 70% or less, and even more preferably 59% or less.

[0053] (Regarding the third additive) However, if some of the europium dissolves in the Ba site as a trivalent donor, it may deteriorate the insulating properties. The inventors have found that co-doping with manganese (Mn), which has the function of reducing excess electrons, is effective. Manganese not only improves the insulating properties, but also increases the valence when subjected to reoxidation treatment, reducing oxygen defects and further improving the lifespan.

[0054] In the dielectric layer 11 of the capacitance region 14, if the amount of manganese relative to titanium in barium titanate, which is the main component of the dielectric layer 11 (the amount of manganese (at %) when titanium is 100 at %), is low, there will be a shortage of acceptors in the dielectric layer 11, and there is a risk that a long life will not be obtained by converting the dielectric layer 11 into a semiconductor. Therefore, in this embodiment, a lower limit is set for the amount of manganese relative to titanium. Specifically, in the dielectric layer 11 of the capacitance region 14, the amount of manganese relative to titanium is set to 0.5 at % or more. The amount of manganese relative to titanium is preferably 0.5 at % or more, and more preferably 1 at % or more.

[0055] On the other hand, if the amount of manganese relative to titanium in the dielectric layer 11 of the capacitance region 14 is high, the amount of acceptors will be excessive, resulting in an excessive number of oxygen vacancies, which may shorten the lifespan. Therefore, in this embodiment, an upper limit is set on the amount of manganese relative to titanium. Specifically, the amount of manganese relative to titanium in the dielectric layer 11 of the capacitance region 14 is set to 4.5 at% or less. The amount of manganese relative to titanium is preferably 3 at% or less, and more preferably 2 at% or less.

[0056] (Regarding the fourth food additive) The inventors have discovered that by adding at least one of strontium and calcium to the dielectric layer 11 in the capacitance region 14 in addition to adding manganese, the insulating properties of the dielectric layer 11 are improved, thereby increasing the life of the multilayer ceramic capacitor 100.

[0057] As shown in Table 1, Ba 2+has an ionic radius of 1.61 Å with 12 coordination atoms. 2+ Sr has 12 coordination atoms and an ionic radius of 1.34 Å. 2+ has an ionic radius of 1.4 Å with a 12-fold coordination. Strontium and calcium have ionic radii similar to those of barium. Therefore, strontium and calcium are generally thought to dissolve in the Ba site of barium titanate and are unlikely to function as acceptors. Therefore, it is thought that the divalent strontium and calcium dissolve in the Ba site in place of some europium, thereby reducing the proportion of trivalent europium dissolved and improving insulation. On the other hand, the improvement in lifetime is thought to be due to the fact that the divalent strontium and calcium ions, which have a smaller ionic radius than divalent Ba, dissolve in barium titanate, shrinking the lattice and limiting the movement of oxygen vacancies, making insulation breakdown less likely.

[0058] In the dielectric layer 11 of the capacitance region 14, if the amount of strontium relative to titanium in barium titanate, which is the main component of the dielectric layer 11 (the amount of strontium (at %) when titanium is 100 at %), is small, the insulating properties of the dielectric layer 11 may not be sufficiently improved. Therefore, in this embodiment, a lower limit is set for the amount of strontium relative to titanium. Specifically, the amount of strontium relative to titanium in the dielectric layer 11 of the capacitance region 14 is set to 0.1 at % or more. The amount of strontium relative to titanium is preferably 0.2 at % or more, and more preferably 0.5 at % or more.

[0059] On the other hand, if the amount of strontium relative to titanium in the dielectric layer 11 of the capacitance region 14 is high, grain growth may progress, resulting in a shortened lifespan. Therefore, in this embodiment, an upper limit is set on the amount of strontium relative to titanium. Specifically, the amount of strontium relative to titanium in the dielectric layer 11 of the capacitance region 14 is set to 3 at% or less. The amount of strontium relative to titanium is preferably 2 at% or less, and more preferably 1 at% or less.

[0060] In the dielectric layer 11 of the capacitance region 14, if the amount of calcium relative to titanium in barium titanate, which is the main component of the dielectric layer 11 (the amount of calcium (at %) when titanium is 100 at %), is small, the insulating properties of the dielectric layer 11 may not be sufficiently improved. Therefore, in this embodiment, a lower limit is set for the amount of calcium relative to titanium. Specifically, in the dielectric layer 11 of the capacitance region 14, the amount of calcium relative to titanium is set to 0.1 at % or more. The amount of calcium relative to titanium is preferably 0.2 at % or more, and more preferably 0.5 at % or more.

[0061] On the other hand, if the amount of calcium relative to titanium in the dielectric layer 11 of the capacitance region 14 is high, grain growth may progress, resulting in a shortened lifespan. Therefore, in this embodiment, an upper limit is set on the amount of calcium relative to titanium. Specifically, the amount of calcium relative to titanium in the dielectric layer 11 of the capacitance region 14 is set to 3 at% or less. The amount of calcium relative to titanium is preferably 2 at% or less, and more preferably 1 at% or less.

[0062] When additives such as zirconium or manganese are dissolved in barium titanate, the Curie temperature of the barium titanate may shift to a lower temperature than 125°C, resulting in a deterioration in the capacitance change rate at high temperatures. In contrast, in this embodiment, the Curie point shifts to a higher temperature (e.g., 130°C) than 125°C, thereby suppressing the deterioration in the capacitance change rate at high temperatures and enabling the multilayer ceramic capacitor 100 to satisfy the X8R characteristics. While the reason for the shift in the Curie point to a higher temperature is not fully understood, it is presumed that this is due to the core portion 31 having a contracted crystal lattice due to the dissolution of part of the europium beyond the shell portion 32 into the core portion 31, and the shell portion 32 having an expanded crystal lattice due to the addition of a high concentration of zirconium, resulting in internal stress at the interface between the core portion 31 and the shell portion 32.

[0063] Next, if the amount of rare earth elements other than europium added to the dielectric layer 11 of the capacitance region 14 is too large, the life-improving effect of europium may be weakened, and sufficient life may not be obtained. Therefore, it is preferable to set an upper limit on the amount of rare earth elements other than europium added. Specifically, it is preferable to set the atomic concentration of the rare earth elements other than europium in the dielectric layer 11 of the capacitance region 14 to be lower than the atomic concentration of europium. When there are multiple types of rare earth elements other than europium, it is preferable to set the total atomic concentration of the multiple types of rare earth elements to be lower than the atomic concentration of europium.

[0064] As described above, according to this embodiment, the dielectric layer 11 in the capacitance region contains barium titanate as the main component, a first additive containing zirconium at 2 at% or more and 10 at% or less relative to the titanium of the barium titanate, a second additive containing europium at 0.2 at% or more and 3.5 at% or less relative to the titanium of the barium titanate, a third additive containing manganese at 0.5 at% or more and 4.5 at% or less relative to the titanium of the barium titanate, and a fourth additive containing at least one of strontium and calcium at 0.1 at% or more and 3 at% or less relative to the titanium of the barium titanate, thereby achieving both a long life and excellent capacitance-temperature characteristics.

[0065] Next, a description will be given of a method for manufacturing the multilayer ceramic capacitor 100. FIG.

[0066] (raw powder production process) First, a dielectric material for forming the dielectric layer 11 is prepared. The A-site elements and B-site elements contained in the dielectric layer 11 are typically contained in the dielectric layer 11 in the form of a sintered body of ABO3 particles. For example, barium titanate is a tetragonal compound with a perovskite structure and exhibits a high dielectric constant. This barium titanate can generally be obtained by synthesizing barium titanate by reacting a titanium raw material such as titanium dioxide with a barium raw material such as barium carbonate. Various methods have been known for synthesizing the ceramic that is the main component of the dielectric layer 11, such as a solid-phase method, a sol-gel method, and a hydrothermal method. Any of these methods can be used in this embodiment.

[0067] The resulting ceramic powder is then mixed with a specific additive compound depending on the intended purpose. Examples of additive compounds include oxides of zirconium, magnesium, manganese, strontium, calcium, vanadium (V), chromium (Cr), and europium, as well as oxides or glasses of cobalt (Co), nickel, lithium (Li), boron (B), sodium (Na), potassium (K), and silicon (Si). Oxides of rare earth elements other than europium, such as scandium (Sc), yttrium, lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), gadolinium (Gd), terbium (Tb), dysprosium, holmium, erbium (Er), thulium (Tm), Yb, and lutetium (Lu), may also be added.

[0068] For example, a ceramic material is prepared by wet-mixing a ceramic raw material powder with a compound containing an additive compound, followed by drying and pulverization. For example, the ceramic material obtained as described above may be pulverized to adjust the particle size, or may be combined with a classification process to adjust the particle size. A dielectric material is obtained through the above process. In the dielectric material, the zirconium content relative to the titanium of barium titanate is 2 at% to 10 at%; the europium content relative to the titanium is 0.2 at% to 3.5 at%; the manganese content relative to the titanium is 0.5 at% to 4.5 at%; and at least one of the strontium content and calcium content relative to the titanium is 0.1 at% to 3 at%.

[0069] (Coating 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. The obtained slurry is used to coat a strip-shaped ceramic green sheet, for example, 0.5 μm or thicker, on a substrate by, for example, a die coater method or a doctor blade method, and then dried.

[0070] (Internal electrode formation process) Next, a metal conductive paste containing an organic binder for forming internal electrodes is printed on the surface of the ceramic green sheet by screen printing, gravure printing, or the like to form an internal electrode pattern that alternately leads to a pair of external electrodes with opposite polarities. 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 it is preferably the same as the main ceramic component of the dielectric layer 11. For example, barium titanate with an average particle diameter of 50 nm or less may be uniformly dispersed.

[0071] (Crimping process) Thereafter, the ceramic green sheets on which the internal electrode patterns are printed are punched out to a predetermined size, and the punched ceramic green sheets are stacked, with the base material peeled off, to a predetermined number of layers (e.g., 100 to 1000 layers) so that the internal electrode layers 12 and the dielectric layers 11 alternate, and so that the edges of the internal electrode layers 12 are alternately exposed at both longitudinal end faces of the dielectric layers 11 and are alternately drawn out to a pair of external electrodes 20a, 20b of opposite polarity. Cover sheets for forming the cover layers 13 are pressure-bonded to the top and bottom of the stacked ceramic green sheets, and the sheets are cut to a predetermined chip size (e.g., 1.0 mm x 0.5 mm).

[0072] (Firing process) The ceramic laminate thus obtained was subjected to binder removal treatment in an N2 atmosphere, and then a metal paste that would become the base layer of the external electrodes 20a, 20b was applied by dipping. -12 MPa~10 -9 The mixture is fired in a reducing atmosphere at 1160°C to 1280°C under a pressure of 100 MPa for 5 minutes to 10 hours.

[0073] If the heating rate is slow, about 10°C / h, the diffusion of rare earth elements and zirconium in the dielectric material barium titanate is promoted, resulting in the formation of fully dissolved particles. In this case, a long life is obtained, but the dielectric constant decreases, and the sintering stability and capacitance-temperature characteristics tend to deteriorate. Therefore, in this embodiment, by setting the heating rate to 5000°C / h or more and 10000°C / h or less (e.g., 6000°C / h), the diffusion of zirconium is suppressed, and a core-shell structure with a large zirconium concentration gradient can be formed.

[0074] In addition, by adjusting the firing conditions such as the particle size of the barium titanate powder in the dielectric material, the firing temperature, and the firing time, the median diameter of the crystal particles 17 in the dielectric layer 11 of the capacitance region 14 obtained after firing can be adjusted.

[0075] (Reoxidation treatment process) In order to return oxygen to the barium titanate, which is the partially reduced main phase of the dielectric layer 11 fired in a reducing atmosphere, heat treatment may be performed in a mixed gas of N2 and water vapor at about 1000°C or in the air at 500°C to 700°C, to a temperature that does not oxidize the internal electrode layer 12. This process is called a reoxidation treatment process.

[0076] (Plating process) Thereafter, the underlying layers of the external electrodes 20a, 20b are plated with a metal coating of Cu, Ni, Sn, etc. Through the above steps, the multilayer ceramic capacitor 100 is completed. [Example]

[0077] The multilayer ceramic capacitor according to the embodiment was fabricated and its characteristics were examined.

[0078] Example 1 Barium titanate, ZrO2, rare earth oxides, MnCO3, SrCO3, CaCO3, SiO2, and organic solvent were weighed out to a specified ratio and mixed and ground using φ0.5mm zirconia beads. The zirconium content relative to titanium in the barium titanate (Zr / Ti) was 4 at%. The europium content relative to titanium (Eu / Ti) was 1 at%. The manganese content relative to titanium was 1 at%. The strontium content relative to titanium was 1 at%. No rare earth elements were added other than europium.

[0079] A binder was added to the slurry, which was then coated onto ceramic green sheets. Internal electrode patterns were printed using Ni paste, the sheets were laminated, and the sheets were cut into a 1005 shape to produce a 1005-shaped ceramic laminate. The ceramic laminate was heated to 1230°C at a rate of 6000°C / h and subjected to rapid firing. In order to reduce oxygen defects that occurred during the reduction firing, the fired multilayer ceramic capacitor was subjected to a reoxidation treatment at 1000°C in a nitrogen atmosphere.

[0080] The thickness of the dielectric layer after firing was 2.0 μm. The thickness of the dielectric layer was measured by polishing with a polishing machine to expose the cross section shown in Figure 6. Images of the cross section were taken with a scanning electron microscope (SEM), and the length was measured at 20 points from five different fields of view, for a total of 100 points, and the average value was calculated. As shown in Figure 6, the crystal grain size is almost uniform in the dielectric layer 11 in the capacitance region. This is thought to be because abnormal grain growth was suppressed by setting the zirconium content relative to titanium to between 2 at% and 10 at%.

[0081] FIG. 7 is a TEM (Transmission Electron Microscope) image of the dielectric layer of the capacitance region. As shown in FIG. 7, a core portion 31 and a shell portion 32 covering the core portion 31 were confirmed in the dielectric layer of the capacitance region after firing. FIG. 8(a) shows the measurement results of TEM-EDS (Energy Dispersive X-ray Spectroscopy) analysis of the shell portion 32. FIG. 8(b) shows the measurement results of TEM-EDS analysis of the core portion 31. As shown in FIGS. 8(a) and 8(b), it can be seen that the zirconium concentration is higher in the shell portion 32 than in the core portion 31. Europium was also confirmed in the core portion 31.

[0082] The X8R characteristics were measured at 1 kHz and 1 Vrms over a temperature range of -55°C to 150°C. The dielectric constant was calculated from the capacitance at 25°C using the dielectric thickness and electrode area. Ten samples were tested at 150°C and a high-temperature, high-field condition of 50 V / μm until they all failed. The average time was used as the lifespan. Table 2 shows the results of the accelerated life test and the X8R characteristics. For accelerated life, a test of 3000 min or more was considered a pass (good), and a test of less than 3000 min was considered a fail (bad). For temperature characteristics, a test that met the X8R characteristics was considered a pass (good), and a test that did not meet the X8R characteristics was considered a fail (bad). If both of these criteria were met, the overall evaluation was a pass (good); if even one of them failed, the overall evaluation was a fail (bad).

[0083] For Example 1, the overall evaluation was "Good." This is thought to be because the dielectric layer 11 in the capacitance region contains barium titanate as the main component, a first additive containing 2 at% to 10 at% zirconium relative to the titanium of the barium titanate, a second additive containing 0.2 at% to 3.5 at% europium relative to the titanium of the barium titanate, a third additive containing 0.5 at% to 4.5 at% manganese relative to the titanium of the barium titanate, and a fourth additive containing at least one of 0.1 at% to 3 at% strontium and calcium relative to the titanium of the barium titanate, thereby achieving both a long life and excellent capacitance-temperature characteristics. Similar results were obtained when the same amount of calcium was used instead of strontium.

[0084] (Comparative Example 1) In Comparative Example 1, ytterbium was used instead of europium. Other conditions were the same as in Example 1.

[0085] (Comparative Example 2) In Comparative Example 2, holmium was used instead of europium. Other conditions were the same as in Example 1.

[0086] (Comparative Example 3) In Comparative Example 3, dysprosium was used instead of europium. Other conditions were the same as in Example 1.

[0087] Comparative Example 4 In Comparative Example 4, terbium was used instead of europium. Other conditions were the same as in Example 1.

[0088] (Comparative Example 5) In Comparative Example 5, gadolinium was used instead of europium. Other conditions were the same as in Example 1.

[0089] (Comparative Example 6) In Comparative Example 6, neodymium was used instead of europium. Other conditions were the same as in Example 1.

[0090] (Comparative Example 7) In Comparative Example 7, praseodymium was used instead of europium. Other conditions were the same as in Example 1.

[0091] (Comparative Example 8) In Comparative Example 8, cerium was used instead of europium. Other conditions were the same as in Example 1.

[0092] (Comparative Example 9) In Comparative Example 9, lanthanum was used instead of europium. Other conditions were the same as in Example 1.

[0093] For Comparative Examples 1 to 9, the accelerated life and X8R characteristics were measured in the same manner as in Example 1, and an overall judgment was made. The accelerated life was judged to be unacceptable in all of Comparative Examples 1 to 9. This is thought to be because a rare earth element other than europium was used. Furthermore, the X8R characteristics were not satisfied in all of Comparative Examples 2 to 9. This is also thought to be because a rare earth element other than europium was used. In Comparative Examples 1 to 9, similar results were obtained when the same amount of calcium was used instead of strontium.

[0094] (Comparative Example 10) In Comparative Example 10, the amount of zirconium relative to titanium was set to 0.5 at %. Other conditions were the same as in Example 1.

[0095] (Comparative Example 11) In Comparative Example 11, the amount of zirconium relative to titanium was 1 at %. Other conditions were the same as in Example 1. Example 2 In Example 2, the amount of zirconium relative to titanium was set to 2 at %. Other conditions were the same as in Example 1.

[0096] Example 3 In Example 3, the amount of zirconium relative to titanium was set to 6 at %. Other conditions were the same as in Example 1.

[0097] Example 4 In Example 4, the amount of zirconium relative to titanium was set to 8 at %. Other conditions were the same as in Example 1.

[0098] Example 5 In Example 5, the amount of zirconium relative to titanium was set to 10 at %. Other conditions were the same as in Example 1.

[0099] (Comparative Example 12) In Comparative Example 12, the amount of zirconium relative to titanium was set to 20 at %. Other conditions were the same as in Example 1.

[0100] Similarly to Example 1, Examples 2 to 5 and Comparative Examples 10 to 12 were also measured for accelerated life and X8R characteristics, and an overall evaluation was made. Examples 2 to 5 were evaluated as passing, with an overall evaluation of "Good." This is thought to be because the dielectric layer 11 in the capacitance region contains barium titanate as the main component, a first additive containing 2 at% to 10 at% zirconium relative to the titanium of the barium titanate, a second additive containing 0.2 at% to 3.5 at% europium relative to the titanium of the barium titanate, a third additive containing 0.5 at% to 4.5 at% manganese relative to the titanium of the barium titanate, and a fourth additive containing at least one of 0.1 at% to 3 at% strontium and calcium relative to the titanium of the barium titanate, thereby achieving both a long life and excellent capacitance-temperature characteristics. In contrast, Comparative Examples 10 and 11 failed the accelerated life evaluation. This is thought to be because the amount of zirconium added was small, making it impossible to maintain the core-shell structure described in Figures 4(a) and 4(b), resulting in localized abnormal grain growth and a failure to achieve a long life. Figure 9 is an SEM image of the lamination cross section of the dielectric layer 11 and internal electrode layer 12 in the capacitance region for Comparative Example 11. As shown in Figure 9, abnormal grain growth was confirmed in the dielectric layer in the capacitance region. Comparative Example 13 failed the temperature characteristics. This is thought to be because the amount of zirconium added was too large. Similar results were obtained for Examples 2 to 4 and Comparative Examples 10 to 13 when the same amount of calcium was used instead of strontium.

[0101] (Comparative Example 13) In Comparative Example 13, the amount of europium relative to titanium was set to 0.05 at %. Other conditions were the same as in Example 1.

[0102] (Comparative Example 14) In Comparative Example 14, the amount of europium relative to titanium was set to 0.1 at %. Other conditions were the same as in Example 1.

[0103] Example 6 In Example 6, the amount of europium relative to titanium was set to 0.5 at %. Other conditions were the same as in Example 1.

[0104] Example 7 In Example 7, the amount of europium relative to titanium was set to 2 at %. Other conditions were the same as in Example 1.

[0105] Example 8 In Example 8, the amount of europium relative to titanium was set to 3 at %. The other conditions were the same as in Example 1.

[0106] (Comparative Example 15) In Comparative Example 15, the amount of europium relative to titanium was 4 at %. The other conditions were the same as in Example 1.

[0107] Similarly to Example 1, the accelerated lifetime and X8R characteristics were measured for Examples 6 to 8 and Comparative Examples 13 to 15, and an overall evaluation was performed. Examples 6 to 8 were evaluated as "good" (pass). This is believed to be because the dielectric layer 11 in the capacitance region contains barium titanate as the main component, a first additive containing 2 at% to 10 at% zirconium relative to the titanium of the barium titanate, a second additive containing 0.2 at% to 3.5 at% europium relative to the titanium of the barium titanate, a third additive containing 0.5 at% to 4.5 at% manganese relative to the titanium of the barium titanate, and a fourth additive containing at least one of 0.1 at% to 3 at% strontium and calcium relative to the titanium of the barium titanate. This allows for both a long lifetime and excellent capacitance-temperature characteristics. In contrast, Comparative Examples 14 and 15 failed the accelerated lifetime evaluation. This is believed to be because the amount of europium added was small, preventing a sufficiently long lifetime. The accelerated life was also unacceptable in Comparative Example 16. This is thought to be because the amount of europium added was too large, and the semiconductor could not achieve a long life. In Examples 6 to 8 and Comparative Examples 13 to 15, similar results were obtained when the same amount of calcium was used instead of strontium.

[0108] (Comparative Example 16) In Comparative Example 16, the amount of manganese relative to titanium was set to 0.1 at %. The other conditions were the same as in Example 1.

[0109] Example 9 In Example 9, the amount of manganese relative to titanium was set to 0.5 at %. Other conditions were the same as in Example 1.

[0110] Example 10 In Example 10, the amount of manganese relative to titanium was set to 2 at %. Other conditions were the same as in Example 1.

[0111] Example 11 In Example 11, the amount of manganese relative to titanium was set to 3 at %. Other conditions were the same as in Example 1.

[0112] (Comparative Example 17) In Comparative Example 17, the amount of manganese relative to titanium was set to 5 at %. The other conditions were the same as in Example 1.

[0113] (Comparative Example 18) In Comparative Example 18, the amount of manganese relative to titanium was set to 10 at %. Other conditions were the same as in Example 1.

[0114] Similarly to Example 1, the accelerated lifetime and X8R characteristics were measured for Examples 9 to 11 and Comparative Examples 16 to 18, and an overall evaluation was performed. Examples 8 to 10 were evaluated as "good" (pass). This is believed to be because the dielectric layer 11 in the capacitance region contains barium titanate as the main component, a first additive containing 2 at% to 10 at% zirconium relative to the titanium of the barium titanate, a second additive containing 0.2 at% to 3.5 at% europium relative to the titanium of the barium titanate, a third additive containing 0.5 at% to 4.5 at% manganese relative to the titanium of the barium titanate, and a fourth additive containing at least one of 0.1 at% to 3 at% strontium and calcium relative to the titanium of the barium titanate, thereby achieving both a long lifetime and excellent capacitance-temperature characteristics. In contrast, Comparative Example 17 failed the accelerated lifetime. This is believed to be due to a lack of acceptors, causing the dielectric layer to become semiconducting. The accelerated lifetime also failed in Comparative Examples 17 and 18. This is thought to be due to an excess of acceptors. In Examples 9 to 11 and Comparative Examples 16 to 18, similar results were obtained when the same amount of calcium was used instead of strontium.

[0115] (Comparative Example 19) In Comparative Example 19, the amount of strontium relative to titanium was set to 0.05 at %. The other conditions were the same as in Example 1.

[0116] Example 12 In Example 12, the amount of strontium relative to titanium was set to 0.1 at %. Other conditions were the same as in Example 1.

[0117] Example 13 In Example 13, the amount of strontium relative to titanium was set to 0.3 at %. Other conditions were the same as in Example 1.

[0118] Example 14 In Example 14, the amount of strontium relative to titanium was set to 0.5 at %. Other conditions were the same as in Example 1.

[0119] (Comparative Example 20) In Comparative Example 20, the amount of strontium relative to titanium was set to 5 at %. Other conditions were the same as in Example 1.

[0120] (Comparative Example 21) In Comparative Example 21, the amount of strontium relative to titanium was set to 10 at %. Other conditions were the same as in Example 1.

[0121] Similarly to Example 1, the accelerated life and X8R characteristics were measured for Examples 12 to 14 and Comparative Examples 19 to 21, and an overall evaluation was performed. Examples 12 to 14 were evaluated as "good" for their overall evaluation. This is believed to be because the dielectric layer 11 in the capacitance region contains barium titanate as the main component, a first additive containing 1 at% to 10 at% zirconium relative to the titanium of the barium titanate, a second additive containing 0.1 at% to 4 at% europium relative to the titanium of the barium titanate, a third additive containing 0.5 at% to 5 at% manganese relative to the titanium of the barium titanate, and a fourth additive containing at least one of 0.1 at% to 3 at% strontium and calcium relative to the titanium of the barium titanate, thereby achieving both a long life and excellent capacitance-temperature characteristics. In contrast, Comparative Example 19 failed the X8R characteristics. This is believed to be due to the small amount of strontium added. In Comparative Examples 20 to 21, the accelerated life was unacceptable. This is thought to be due to the large amount of strontium added, which caused grain growth. In Examples 12 to 14 and Comparative Examples 19 to 21, similar results were obtained when the same amount of calcium was used instead of strontium.

[0122] (Comparative Example 22) In Comparative Example 22, the conditions of Example 1 were followed except that holmium was further added in an amount of 1 at % relative to titanium.

[0123] For Comparative Example 22, the accelerated life and X8R characteristics were measured and a comprehensive evaluation was made in the same manner as in Example 1. Comparative Example 22 failed both the accelerated life and the temperature characteristics. This is thought to be because the europium content was not greater than the other rare earth elements. [Table 2]

[0124] 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 are possible within the scope of the gist of the present invention as defined in the claims. [Explanation of symbols]

[0125] 10 stacked chips 11 Dielectric layer 12 Internal electrode layer 13 Cover Layer 14 capacity area 15 End Margin 16 Side Margin 20a,20b external electrode 100 Multilayer ceramic capacitors

Claims

1. A main component including barium titanate; A first additive containing zirconium in an amount of 2 at% to 10 at% relative to the titanium of the barium titanate; a second additive containing europium in an amount of 0.2 at% or more and 3.5 at% or less relative to the titanium of the barium titanate, and containing rare earth elements other than europium in an amount less than that of europium; A third additive containing manganese in an amount of 0.5 at% or more and 4.5 at% or less relative to the titanium of the barium titanate; A fourth additive containing at least one of strontium and calcium in an amount of 0.1 at% or more and 3 at% or less relative to the titanium of the barium titanate; A dielectric composition comprising a dielectric crystal having a core portion in which europium is dissolved and a shell portion that covers the core portion and has a higher zirconium concentration than the core portion.

2. 2. The dielectric composition according to claim 1, wherein the second additive contains divalent europium and trivalent europium, and the divalent europium accounts for 21% or more and 80% or less of the total europium contained in the second additive.

3. 3. The dielectric composition according to claim 1, wherein the first additive contains zirconium in an amount of 2 at % or more and 8 at % or less relative to the titanium in the barium titanate.

4. 4. The dielectric composition according to claim 1, wherein the second additive contains europium in an amount of 0.5 at % or more and 3 at % or less relative to the titanium in the barium titanate.

5. 5. The dielectric composition according to claim 1, wherein the third additive contains manganese in an amount of 0.5 at % or more and 3 at % or less relative to the titanium in the barium titanate.

6. 6. The dielectric composition according to claim 1, wherein the fourth additive contains at least one of strontium and calcium in an amount of 0.1 at % or more and 1 at % or less relative to the titanium of the barium titanate.

7. a first additive containing zirconium at 2 at% or more and 10 at% or less relative to the titanium of the barium titanate; a second additive containing europium at 0.2 at% or more and 3.5 at% or less relative to the titanium of the barium titanate, and containing rare earth elements other than europium less than europium; a third additive containing manganese at 0.5 at% or more and 4.5 at% or less relative to the titanium of the barium titanate; a fourth additive containing at least one of strontium and calcium at 0.1 at% or more and 3 at% or less relative to the titanium of the barium titanate; and a dielectric crystal having a core portion in which europium is solid-dissolved and a shell portion covering the core portion and having a higher zirconium concentration than the core portion; a plurality of internal electrode layers laminated with the plurality of dielectric layers interposed therebetween; and external electrodes electrically connected to the plurality of internal electrode layers.

8. 8. The multilayer ceramic electronic component according to claim 7, wherein the second additive contains divalent europium and trivalent europium, and the divalent europium accounts for 21% to 80% of the total europium contained in the second additive.

9. 9. The multilayer ceramic electronic component according to claim 7, wherein the first additive contains zirconium in an amount of 2 at % to 8 at % relative to the titanium in the barium titanate.

10. 10. The multilayer ceramic electronic component according to claim 7, wherein the second additive contains europium in an amount of 0.5 at % to 3 at % relative to the titanium in the barium titanate.

11. 11. The multilayer ceramic electronic component according to claim 7, wherein the third additive contains manganese in an amount of 0.5 at % to 3 at % relative to the titanium in the barium titanate.

12. 12. The multilayer ceramic electronic component according to claim 7, wherein the fourth additive contains at least one of strontium and calcium in an amount of 0.1 at % to 1 at % relative to the titanium in the barium titanate.

13. The multilayer ceramic electronic component according to claim 7 , which satisfies X8R characteristics.

14. a step of forming a ceramic green sheet including a main component containing barium titanate, a first additive containing zirconium at 2 at% to 10 at% relative to the titanium of the barium titanate, a second additive containing europium at 0.2 at% to 3.5 at% relative to the titanium of the barium titanate and containing fewer rare earth elements other than europium than europium, a third additive containing manganese at 0.5 at% to 4.5 at% relative to the titanium of the barium titanate, and a fourth additive containing at least one of strontium and calcium at 0.1 at% to 3 at% relative to the titanium of the barium titanate; and firing the ceramic green sheet at a temperature increase rate of 5,000° C. / h or more and 10,000° C. / h or less.

15. a coating process for forming a ceramic green sheet including a main component containing barium titanate, a first additive containing zirconium at 2 at% to 10 at% relative to the titanium of the barium titanate, a second additive containing europium at 0.2 at% to 3.5 at% relative to the titanium of the barium titanate and containing fewer rare earth elements other than europium than europium, a third additive containing manganese at 0.5 at% to 4.5 at% relative to the titanium of the barium titanate, and a fourth additive containing at least one of strontium and calcium at 0.1 at% to 3 at% relative to the titanium of the barium titanate; an internal electrode forming step of forming an internal electrode pattern on the ceramic green sheet; a pressure bonding step of stacking the ceramic green sheets on which the internal electrode patterns are formed; and a firing step of firing the laminated ceramic green sheets at a temperature rise rate of 5,000°C / h or more and 10,000°C / h or less to form a plurality of dielectric layers and a plurality of internal electrodes.

16. The method for producing a multilayer ceramic electronic component according to claim 15, further comprising a reoxidation step of heat-treating the plurality of dielectric layers and the plurality of internal electrodes after the firing step.

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