Multilayer ceramic capacitors and dielectric materials

Abstract

The stacked ceramic capacitor includes a stacked structure having a substantially rectangular parallelepiped shape and including alternating dielectric layers and internal electrode layers, the dielectric layers being mainly composed of BaTiO3, and the internal electrode layers being alternately exposed on two end faces of the stacked chip facing each other. In the capacitor portion, the Zr / Ti ratio is greater than 0.02 and less than 0.10. In the capacitor portion, the Ba / Ti ratio is greater than 0.900 and less than 1.010. In the capacitor portion, the Eu / Ti ratio is greater than 0.005 and less than 0.05. In the capacitor portion, the Mn / Ti ratio is greater than 0.0005 and less than 0.05. The total amount of one or more rare earth elements other than Eu or rare earth elements is less than the amount of Eu.

Description

Field of the Invention

[0001] Certain aspects of the present disclosure relate to stacked ceramic capacitors and dielectric materials. Background Art

[0002] In high-frequency communication systems such as mobile phones, ceramic electronic devices such as stacked ceramic capacitors are currently used to eliminate noise (for example, see Japanese Patent Application Laid-Open No. 2013-197492). Summary of the Invention

[0003] According to a first aspect of an embodiment, a multilayer ceramic capacitor is provided, comprising: a multilayer structure having a substantially rectangular parallelepiped shape and including alternately stacked dielectric layers and internal electrode layers, the dielectric layers primarily composed of BaTiO3, the internal electrode layers alternately exposed at two opposing end faces of a multilayer chip, wherein, in a capacitor portion where the internal electrode layers exposed at different end faces of the multilayer structure oppose each other, a Zr / Ti ratio, which is a ratio of the amount of Zr to the amount of Ti, is 0.02 or greater and 0.10 or less, wherein, in the capacitor portion, a Ba / Ti ratio, which is a ratio of the amount of Ba to the amount of Ti, is greater than 0.900 and less than 1.010, wherein, in the capacitor portion, a Eu / Ti ratio, which is a ratio of the amount of Eu to the amount of Ti, is 0.005 or greater and 0.05 or less, wherein, in the capacitor portion, a Mn / Ti ratio, which is a ratio of the amount of Mn to the amount of Ti, is 0.0005 or greater and 0.05 or less, and wherein the total amount of one or more rare earth elements other than Eu is less than the amount of Eu.

[0004] According to a second aspect of the embodiment, there is provided a dielectric material comprising: BaTiO3 powder; and an additive compound, wherein a Zr / Ti ratio, which is a ratio of the amount of Zr to the amount of Ti, is greater than 0.02 and less than 0.10, wherein a Ba / Ti ratio, which is a ratio of the amount of Ba to the amount of Ti, is greater than 0.900 and less than 1.010, wherein a Eu / Ti ratio, which is a ratio of the amount of Eu to the amount of Ti, is greater than 0.005 and less than 0.05, wherein a Mn / Ti ratio, which is a ratio of the amount of Mn to the amount of Ti, is greater than 0.0005 and less than 0.05, and wherein the total amount of one or more rare earth elements other than Eu is less than the amount of Eu. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 is a partial cross-sectional perspective view of a multilayer ceramic capacitor;

[0006] Figure 2 It is along Figure 1 A sectional view taken along line AA;

[0007] Figure 3 It is along Figure 1 A sectional view taken along line BB;

[0008] Figure 4A A core-shell particle is schematically shown;

[0009] Figure 4B schematically showing a cross-sectional view of a dielectric layer;

[0010] Figure 5 is a flow chart of a method for manufacturing a laminated ceramic capacitor; and

[0011] Figure 6 The dimensions of the core-shell structure are shown. DETAILED DESCRIPTION

[0012] When ceramic electronic devices have a core-shell structure (wherein the core is made of a ceramic as the main component), and a shell in which various additives are solid-dissolved surrounds the core, a dielectric material having a high dielectric constant, excellent temperature characteristics, and a stable microstructure is obtained. Mg (magnesium) is a typical example of an additive that constitutes the shell. However, Mg is a simple acceptor with a constant valence. Mg is solid-dissolved in the dielectric material and generates oxygen vacancies. Therefore, reliability is not fully improved.

[0013] Hereinafter, exemplary embodiments will be described with reference to the accompanying drawings.

[0014] [Exemplary Embodiments]

[0015] Figure 1 A perspective view of a multilayer ceramic capacitor 100 according to an embodiment is shown, in which a cross section of a portion of the multilayer ceramic capacitor 100 is shown. Figure 2 It is along Figure 1 A cross-sectional view taken along line AA. Figure 3 It is along Figure 1 The cross-sectional view taken along line BB of Figures 1 to 3 As shown, the laminated ceramic capacitor 100 includes: a laminated chip 10 having a rectangular parallelepiped shape; and external electrodes 20a and 20b, respectively, disposed on two opposing end faces (edge ​​faces) of the laminated chip 10. Of the four faces other than the two end faces of the laminated chip 10, the two faces other than the top and bottom faces in the stacking direction are referred to as side faces. Each of the external electrodes 20a and 20b extends to the top and bottom faces and two side faces of the laminated chip 10 in the stacking direction. However, the external electrodes 20a and 20b are spaced apart from each other.

[0016] The laminated chip 10 has a structure designed to have alternating dielectric layers 11 and internal electrode layers 12. The dielectric layers 11 contain a ceramic material serving as a dielectric material. The end edges of the internal electrode layers 12 are alternately exposed at a first end surface of the laminated chip 10 and a second end surface of the laminated chip 10 that is different from the first end surface. External electrodes 20a are provided on the first end surface. External electrodes 20b are provided on the second end surface. Thus, the internal electrode layers 12 are alternately electrically connected to the external electrodes 20a and 20b. Therefore, the laminated ceramic capacitor 100 has a structure in which a plurality of dielectric layers 11 are stacked with internal electrode layers 12 sandwiched therebetween. In the stacked structure of the dielectric layers 11 and the internal electrode layers 12, the outermost layers in the stacking direction are the internal electrode layers 12, and the cover layers 13 cover the top and bottom surfaces of the stacked structure. The cover layers 13 are primarily composed of a ceramic material. For example, the main component of the cover layer 13 is the same as that of the dielectric layers 11.

[0017] For example, the laminated ceramic capacitor 100 may have a length of 0.25 mm, a width of 0.125 mm, and a height of 0.125 mm. The laminated ceramic capacitor 100 may have a length of 0.4 mm, a width of 0.2 mm, and a height of 0.2 mm. The laminated ceramic capacitor 100 may have a length of 0.6 mm, a width of 0.3 mm, and a height of 0.3 mm. The laminated ceramic capacitor 100 may have a length of 1.0 mm, a width of 0.5 mm, and a height of 0.5 mm. The laminated ceramic capacitor 100 may have a length of 3.2 mm, a width of 1.6 mm, and a height of 1.6 mm. The laminated ceramic capacitor 100 may have a length of 4.5 mm, a width of 3.2 mm, and a height of 2.5 mm. However, the size of the laminated ceramic capacitor 100 is not limited.

[0018] The internal electrode layer 12 is mainly composed of a base metal such as nickel (Ni), copper (Cu), or tin (Sn). The internal electrode layer 12 may be composed of a noble metal such as platinum (Pt), palladium (Pd), silver (Ag), or gold (Au), or an alloy including one or more of these.

[0019] The dielectric layer 11 is mainly composed of a ceramic material having a perovskite structure represented by the general formula ABO3. The perovskite structure includes ABO with a non-stoichiometric composition. 3-α In the embodiment, BaTiO 3 (barium titanate) is used as the ceramic material. For example, the dielectric layer 11 is formed by firing a dielectric material including a ceramic material powder whose main component is a ceramic material having a perovskite structure.

[0020] like Figure 2As shown, the portion where the internal electrode layer 12 connected to the external electrode 20a faces the internal electrode layer 12 connected to the external electrode 20b is the portion generating capacitance in the multilayer ceramic capacitor 100. Therefore, this region is referred to as a capacitance portion 14. That is, the capacitance portion 14 is a portion where two adjacent internal electrode layers 12 connected to different external electrodes face each other.

[0021] The portion where internal electrode layers 12 connected to external electrode 20a face each other without interposing an internal electrode layer 12 connected to external electrode 20b is called an end margin 15. The portion where internal electrode layers 12 connected to external electrode 20b face each other without interposing an internal electrode layer 12 connected to external electrode 20a is also an end margin 15. That is, end margin 15 is a portion where internal electrode layers 12 connected to one external electrode face each other without interposing an internal electrode layer 12 connected to the other external electrode. End margin 15 is a portion that does not generate capacitance.

[0022] like Figure 3 As shown, in the laminated chip 10, the portion extending from each of the two side surfaces of the laminated chip 10 to the internal electrode layer 12 is referred to as a side edge 16. In other words, the side edge 16 is a portion extending toward each side surface of the laminated structure and covering each edge of the laminated internal electrode layer 12. The side edge 16 is a portion that does not generate capacitance.

[0023] When at least a portion of BaTiO 3 grains in dielectric layer 11 of capacitor portion 14 of multilayer ceramic capacitor 100 have a core-shell structure, dielectric layer 11 in capacitor portion 14 has a high dielectric constant and excellent temperature characteristics. In this case, a stable microstructure coexists.

[0024] For example, Mg is a representative additive for forming the shell. However, Mg is a simple acceptor with a constant valence. When Mg is dissolved in BaTiO3 in the dielectric layer 11, oxygen vacancies are formed. Therefore, it may be difficult to improve reliability.

[0025] Therefore, in the embodiment, at least some of the BaTiO 3 crystal grains in the dielectric layer of the capacitor portion 14 have a core-shell structure in which BaTiO 3 serves as a core and the layer in which Zr (zirconium) is diffused serves as a shell. The main component of the shell is BaTiO 3.

[0026] like Figure 4AAs shown, the core-shell particle 30 has a spherical core 31 and a shell 32 covering and surrounding the core 31. The core 31 is a crystalline portion in which no additive compound is solid-dissolved or the amount of the dissolved additive compound is very small. The shell 32 is a crystalline portion in which the additive compound is solid-dissolved. Moreover, the additive compound concentration of the shell 32 is higher than the additive compound concentration of the core 31. In an embodiment, the Zr concentration in the shell 32 is higher than the Zr concentration in the core 31. Alternatively, Zr diffuses into the shell 32, and Zr does not diffuse into the core 31.

[0027] Figure 4B The cross section of the dielectric layer 11 is schematically shown. Figure 4B As shown, the dielectric layer 11 includes a plurality of crystal grains 17 of ceramic as a main component. At least a portion of the crystal grains 17 is formed according to Figure 4A The core-shell particles 30 are described.

[0028] When the core is covered with a shell whose main component is Zr, which has high reduction resistance, a high dielectric constant is maintained and a stable structure is obtained. In addition, a highly reliable material is obtained. However, when doped with Zr, the lattice constant of the BaTiO3 crystal increases, and the amount of rare earth elements dissolved in the B site is greater than that in the A site. In this case, the number of acceptors is too large. Therefore, the improvement of the life characteristics is limited. Rare earth elements such as Ho (holmium), Dy (dysprosium), Y (yttrium), etc. play an important role in the life characteristics.

[0029] Therefore, the inventors studied rare earth elements with large ionic radius that are easily dissolved in the A site of BaTiO3. The inventors found that the lifespan when Eu (europium) was added was about one digit higher than the lifespan when rare earth elements such as Ho, Dy or Y were added. The reason why the lifespan was improved by adding Eu has not yet been fully explained. Eu with a valence of 2 and Eu with a valence of 3 are stable. The valence of Eu fluctuates between 2 and 3. Among stable rare earth ions, the ionic radius of Eu with a valence of 2 is the largest. Therefore, Eu may tend to be dissolved in the A site. However, when a portion of Eu has a valence of 3 and is dissolved in the A site, Eu acts as a donor and may reduce the insulating properties. Therefore, Mn (manganese) is added to reduce the number of excess electrons. Mn can improve the insulating properties. When the reoxidation process is carried out, the valence of Mn increases. Therefore, Mn reduces the number of oxygen vacancies. And the lifespan is increased even more. When the valence of a rare earth element is 3, all rare earth elements except Eu are stable. When the valence of a rare earth element is 2, the rare earth element is unstable.

[0030] Table 1 shows the ionic radius of rare earth elements having a coordination number of 6. The source of Table 1 is "RD Shannon, Acta Crystallogr., A32, 751 (1976)".

[0031] [Table 1]

[0032]

[0033] Eu is more easily dissolved in the shell 32 than in the core 31. Therefore, the concentration of Eu in the shell 32 is higher than that in the core 31. Alternatively, Eu is dissolved in the shell 32, and Eu is not dissolved in the core 31.

[0034] When a sufficient amount of Zr is not added to the dielectric layer in the capacitor portion 14, the core-shell structure described above cannot be maintained during the firing process of the dielectric layer 11. In this case, local abnormal grain growth may occur. A sufficient lifespan may not necessarily be achieved. Furthermore, the X5R characteristics of the EIA standard (the capacitance change rate from the standard capacitance at 25°C to 85°C is within ±15%) may not necessarily be achieved. Therefore, in an embodiment, the Zr / Ti ratio, which is the ratio of the amount of Zr to the amount of Ti, has a lower limit. Specifically, the Zr / Ti ratio is greater than 0.02. The Zr / Ti ratio is preferably greater than 0.03. The Zr / Ti ratio is more preferably greater than 0.04.

[0035] On the other hand, if the amount of Zr in the dielectric layer 11 of the capacitor portion 14 is too high, grain growth may occur during the firing of the dielectric layer 11, and a sufficient lifespan may not be achieved. Therefore, in the embodiment, the Zr / Ti ratio has an upper limit. Specifically, the Zr / Ti ratio is 0.10 or less. The Zr / Ti ratio is preferably 0.08 or less. The Zr / Ti ratio is more preferably 0.06 or less.

[0036] Next, if the Ba / Ti ratio, which is the ratio of the amount of Ba to the amount of Ti in the dielectric layer 11 in the capacitor portion 14, is too large, grain growth may occur during the firing of the dielectric layer, and a sufficient lifespan may not be achieved. Therefore, in the embodiment, the Ba / Ti ratio has an upper limit. Specifically, the Ba / Ti ratio is less than 1.010. The Ba / Ti ratio is preferably 1.005 or less. The Ba / Ti ratio is more preferably 1.003 or less.

[0037] On the other hand, if the Ba / Ti ratio in the dielectric layer 11 of the capacitor portion 14 is too low, the amount of Ti becomes relatively large, and the effect of Zr becomes less. Therefore, a sufficient lifespan may not necessarily be achieved. Therefore, in the embodiment, the Ba / Ti ratio has a lower limit. Specifically, the Ba / Ti ratio is greater than 0.900. The Ba / Ti ratio is preferably greater than 0.950. The Ba / Ti ratio is more preferably greater than 1.000.

[0038] When the relationship of 0.02≤Zr / Ti ratio≤0.10 and the relationship of 0.900<Ba / Ti ratio<1.010 are satisfied in the dielectric layer 11 in the capacitor portion 14, a dielectric layer in which the core is BaTiO 3 and the shell is BaTiO 3 is obtained. x Zr 1-x The core-shell structure of BaTiO3 is not a structure in which two particles of BaTiO3 and BaZrO3 are mixed.

[0039] Next, when the amount of Eu added to the dielectric layer 11 in the capacitor section 14 is too small, sufficient life may not necessarily be achieved. Therefore, in the embodiment, the amount of Eu added has a lower limit. Specifically, in the dielectric layer 11 in the capacitor section 14, the Eu / Ti ratio, which represents the ratio of the amount of Eu to the amount of Ti, is 0.005 or more. The Eu / Ti ratio is preferably 0.0075 or more. The Eu / Ti ratio is more preferably 0.01 or more.

[0040] When the amount of Eu added in the dielectric layer 11 in the capacitor section 14 is too large, the insulating properties may deteriorate. Moreover, a sufficient lifespan may not necessarily be achieved. Therefore, in an embodiment, the amount of Eu added has an upper limit. Specifically, in the dielectric layer 11 of the capacitor section 14, the Eu / Ti ratio is less than 0.05. The Eu / Ti ratio is preferably less than 0.03. The Eu / Ti ratio is more preferably less than 0.02.

[0041] Next, when the amount of rare earth elements other than Eu in the dielectric layer 11 in the capacitor portion 14 is excessive, the effect of Eu in improving the lifespan may become smaller. Moreover, a sufficient lifespan may not necessarily be achieved. Therefore, in an embodiment, the content of rare earth elements other than Eu has an upper limit. Specifically, the amount of rare earth elements other than Eu is less than the amount of Eu. When the number of rare earth elements other than Eu is two or more, the total amount of rare earth elements other than Eu is less than the amount of Eu.

[0042] When the amount of Mn added in the dielectric layer 11 in the capacitor section 14 is too little, the insulating properties may deteriorate. Moreover, sufficient life may not necessarily be achieved. Therefore, in an embodiment, the amount of Mn added has a lower limit. Specifically, in the dielectric layer 11 in the capacitor section 14, the Mn / Ti ratio representing the ratio of the Mn amount to the Ti amount is 0.0005 or more. The Mn / Ti ratio is preferably 0.001 or more. The Mn / Ti ratio is more preferably 0.0015 or more.

[0043] When the Mn addition in the dielectric layer 11 in the capacitor portion 14 is too large, many oxygen vacancies may be formed. And, sufficient life may not necessarily be achieved. Therefore, in an embodiment, the addition of Mn has an upper limit. Specifically, in the dielectric layer 11 of the capacitor portion 14, the Mn / Ti ratio is less than 0.05. The Mn / Ti ratio is preferably less than 0.02. The Mn / Ti ratio is more preferably less than 0.01.

[0044] When Zr diffuses into BaTiO3 and solid-dissolves in BaTiO3, the Curie temperature of BaTiO3 decreases. Therefore, when the layer diffused with Zr is too thick, the capacitance is greatly reduced at high temperatures. In addition, the X5R performance may not necessarily be satisfied. In the core-shell structure, such as Figure 6 As shown in the figure, the length of the major axis of the particle diameter is called "D". Figure 6 As shown, the major axis length of the core diameter is referred to as "d". When the d / D ratio (which is the ratio of the major axis length of the core diameter to the major axis length of the particle diameter) is less than 0.3, X5R performance may not necessarily be achieved. Therefore, it is preferred that the d / D ratio is 0.3 or more. The d / D ratio is more preferably 0.4 or more. The d / D ratio is more preferably 0.5 or more. On the other hand, when the d / D ratio is greater than 0.9, additives such as Zr or Eu cannot be fully diffused and solid-dissolved in BaTiO3. Therefore, the life may be short. Therefore, the d / D ratio is preferably 0.9 or less. The d / D ratio is more preferably 0.8 or less. The d / D ratio is more preferably 0.7 or less. "d" and "D" can be measured by using TEM (transmission electron microscope). "d" and "D" can be calculated by calculating the average value of 20 randomly selected dielectric particles. When the core does not exist (continuous solid solution), "d" is 0.

[0045] Next, a method of manufacturing the laminated ceramic capacitor 100 will be described. Figure 5 1 is a flowchart of a method for manufacturing the multilayer ceramic capacitor 100 .

[0046] [Manufacturing raw material powder (S1)]

[0047] A dielectric material for forming the dielectric layer 11 is prepared. The A-site element and the B-site element contained in the dielectric layer 11 are generally contained in the dielectric layer 11 in the form of a sintered compact of ABO3 particles. For example, BaTiO3 is a tetragonal compound having a perovskite structure and exhibiting a high dielectric constant. Generally, the BaTiO3 is obtained by reacting a titanium raw material such as titanium dioxide with a barium raw material such as barium carbonate to synthesize barium titanate. As a method for synthesizing ceramics constituting the dielectric layer 11, many methods are known. For example, a solid phase method, a sol-gel method, a hydrothermal method, etc. are known. This embodiment can use any of these methods.

[0048] Depending on the purpose, additive compounds may be added to the resulting ceramic powder. The additive compound may be an oxide of Zr, Mg, V (vanadium), Cr (chromium), or Eu, or an oxide of cobalt (Co), Ni, lithium (Li), boron (boron), sodium (Na), potassium (K), or silicon (silicon), or glass. Oxides of rare earth elements other than Eu may be used. Examples of rare earth elements include Sc (scandium), Y, La (lanthanum), Ce (cerium), Pr (praseodymium), Nd (neodymium), Pm (promethium), Sm (samarium), Gd (gadolinium), Tb (terbium), Dy, Ho, Er (erbium), Tm (thulium), Yb (ytterbium), or Lu (lutetium).

[0049] For example, a compound including an additive is wet-mixed with the obtained ceramic material powder. The obtained ceramic material powder is dried and pulverized. For example, if necessary, the obtained ceramic material is pulverized. This allows the particle size to be adjusted. Alternatively, the particle size can be further adjusted through a classification process. Thus, a dielectric material is obtained.

[0050] In the dielectric material, the Zr / Ti ratio, which is the ratio of the amount of Zr to the amount of Ti, is 0.02 or greater and 0.10 or less. In the dielectric material, the Ba / Ti ratio, which is the ratio of the amount of Ba to the amount of Ti, is greater than 0.900 and less than 1.010. In the dielectric material, the Eu / Ti ratio, which is the ratio of the amount of Eu to the amount of Ti, is 0.005 or greater and 0.05 or less. In the dielectric material, the Mn / Ti ratio, which is the ratio of the amount of Mn to the amount of Ti, is 0.0005 or greater and 0.05 or less. In the dielectric material, the total amount of one or more rare earth elements other than Eu is less than the amount of Eu.

[0051] [Lamination Step (S2)]

[0052] Next, a binder such as polyvinyl butyral (PVB) resin, an organic solvent such as ethanol or toluene, and a plasticizer are added to the resulting dielectric material and wet-mixed. Using the resulting slurry, a strip-shaped dielectric green sheet having a thickness of, for example, 0.5 μm or greater is applied to a substrate using, for example, a die coater or doctor blade method, and then dried.

[0053] Next, a metal conductive paste for forming internal electrodes is printed using screen printing or gravure printing to form internal electrode layer patterns on the surface of the dielectric green sheet. The metal conductive paste for forming the internal electrodes contains an organic binder. Multiple internal electrode layer patterns are alternately exposed to a pair of external electrodes. Ceramic particles are added to the metal conductive paste as a co-material. The main component of the ceramic particles is not particularly limited, but is preferably the same as the main component of the ceramic of dielectric layer 11. For example, BaTiO3 with an average particle size of 50 nm or less can be uniformly dispersed.

[0054] Thereafter, the dielectric green sheet on which the internal electrode layer pattern is printed is punched into a predetermined size, and a predetermined number (e.g., 100 to 1000) of the punched dielectric green sheets are stacked while the substrate is peeled off, so that the internal electrode layers 12 and the dielectric layers 11 alternate with each other, and the end edges of the internal electrode layers 12 are alternately exposed at the two end faces in the longitudinal direction of the dielectric layer so as to be alternately led to a pair of external electrodes of different polarities. A cover sheet, which will become the cover layer 13, is clamped between the top and bottom surfaces of the stacked dielectric green sheets in the stacking direction. Furthermore, the resulting stacked structure is cut into a predetermined chip size (e.g., 1.0 mm × 0.5 mm). When the temperature increase rate in the firing process is approximately 10°C / h, the diffusion of Zr is excessively promoted. Furthermore, continuous solid solution particles can be formed. Therefore, in an embodiment, a rapid temperature increase of 6000°C / h is performed. Therefore, the diffusion distance of Zr is limited. Furthermore, a core-shell structure can be formed.

[0055] [Firing step (S3)]

[0056] The binder was removed from the obtained ceramic laminated structure under N2 atmosphere. Thereafter, Ni paste to be used as the base layer of the external electrodes 20a and 20b was printed. The Ni paste was heated in the temperature range of 1100°C to 1300°C under an oxygen partial pressure of 10 -12 to 10 -9 The obtained ceramic multilayer structure is fired in a reducing atmosphere of 0.5 atm for 10 minutes to 2 hours. In this way, the multilayer ceramic capacitor 100 is obtained.

[0057] [Reoxidation step (S4)]

[0058] Thereafter, a reoxidation process is performed in a N2 gas atmosphere at a temperature range of 600°C to 1000°C.

[0059] [Plating step (S5)]

[0060] Thereafter, a metal layer such as Cu, Ni, Sn, etc. may be formed on the external electrodes 20a and 20b by plating. Through these processes, the multilayer ceramic capacitor 100 is manufactured.

[0061] In the manufacturing method of this embodiment, the following structure is formed in at least a portion of the dielectric layer 11 in the capacitor portion 14: Figure 4AThe core-shell particles 30 shown. In the dielectric layer 11 in the capacitor portion 14, the Zr / Ti ratio, which is the ratio of the amount of Zr to the amount of Ti, is greater than 0.02 and less than 0.10. In the dielectric layer 11 in the capacitor portion 14, the Ba / Ti ratio, which is the ratio of the amount of Ba to the amount of Ti, is greater than 0.900 and less than 1.010. In the dielectric layer 11 in the capacitor portion 14, the Eu / Ti ratio, which is the ratio of the amount of Eu to the amount of Ti, is greater than 0.005 and less than 0.05. In the dielectric layer 11 in the capacitor portion 14, the Mn / Ti ratio, which is the ratio of the amount of Mn to the amount of Ti, is greater than 0.0005 and less than 0.05. The total amount of one or more rare earth elements other than Eu is less than the amount of Eu. Therefore, in the multilayer ceramic capacitor 100, a high dielectric constant and excellent temperature characteristics are maintained, and high reliability is achieved.

[0062] [Example]

[0063] The multilayer ceramic capacitor according to the embodiment was manufactured and its performance was measured.

[0064] (Example 1) Barium titanate powder with an average particle size of 100 nm was prepared as a dielectric material. Additives such as ZrO2, Eu oxide, and MnCO3 were added to the barium titanate powder. The resulting barium titanate powder was mixed and pulverized using 0.5 mm φ zirconium oxide beads. This yielded a dielectric material. The Zr / Ti ratio was 0.02, the Ba / Ti ratio was 1.003, the Eu / Ti ratio was 0.01, and the Mn / Ti ratio was 0.005.

[0065] An organic binder and solvent are added to the resulting dielectric material. The resulting slurry is used to prepare dielectric green sheets using a doctor blade method. Polyvinyl butyral (PVB) or the like is used as the organic binder. Ethanol, toluene, or the like is used as the solvent. A plasticizer is then added to the resulting dielectric material.

[0066] Next, a planetary ball mill is used to prepare a metal conductive paste for forming the internal electrode layer 12. The metal conductive paste includes a main component metal of the internal electrode layer 12, a co-material, a binder (ethyl cellulose), a solvent, and additives as needed.

[0067] A metallic conductive paste for forming internal electrode layers is screen-printed onto each dielectric green sheet. Fifteen sheet members, each with the metallic conductive paste printed on the dielectric green sheets, are stacked. Cover sheets are stacked above and below the stacked green sheets. The stacked structure is then hot-pressed to form a desired shape.

[0068] The adhesive is removed from the resulting laminated structure under an N2 atmosphere. Thereafter, a metal conductive paste comprising a metal filler whose main component is Ni, a common material, an adhesive, a solvent, etc. is printed from both end faces to each side of the laminated structure and dried. The metal conductive paste for the base layer and the laminated structure are fired together in a reducing atmosphere at a temperature range of 1100°C to 1300°C for 10 minutes to 2 hours. Thus, a sintered structure is formed. The heating rate is 6000°C / h. The length, width and height of the sintered structure are 0.6 mm, 0.3 mm and 0.3 mm, respectively. Thereafter, a reoxidation process is performed. Thereafter, a Cu plating layer, a Ni plating layer and a Sn plating layer are formed on the surface of the base layer by a plating method. Thus, a laminated ceramic capacitor 100 is manufactured. The average thickness of the dielectric layer 11 is 2.0 μm.

[0069] (Example 2) In Example 2, the Zr / Ti ratio of the dielectric material was 0.04. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.005. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0070] (Example 3) In Example 3, the Zr / Ti ratio of the dielectric material was 0.04. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.01. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0071] (Example 4) In Example 4, the Zr / Ti ratio of the dielectric material was 0.04. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.015. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0072] (Example 5) In Example 5, the Zr / Ti ratio of the dielectric material was 0.04. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.02. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0073] (Example 6) In Example 6, the Zr / Ti ratio of the dielectric material was 0.04. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.03. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0074] (Example 7) In Example 7, the Zr / Ti ratio of the dielectric material was 0.04. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.05. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0075] (Example 8) In Example 8, the Zr / Ti ratio of the dielectric material was 0.04. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.01. The Mn / Ti ratio of the dielectric material was 0.005. Ho₂O₃ was added to the dielectric material. The Ho / Ti ratio, which is the ratio of the amount of Ho to the amount of Ti, was 0.005. Other conditions were the same as in Example 1.

[0076] (Example 9) In Example 9, the Zr / Ti ratio of the dielectric material was 0.04. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.01. The Mn / Ti ratio of the dielectric material was 0.0005. Other conditions were the same as in Example 1.

[0077] (Example 10) In Example 10, the Zr / Ti ratio of the dielectric material was 0.04. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.01. The Mn / Ti ratio of the dielectric material was 0.02. Other conditions were the same as in Example 1.

[0078] (Example 11) In Example 11, the Zr / Ti ratio of the dielectric material was 0.04. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.01. The Mn / Ti ratio of the dielectric material was 0.05. Other conditions were the same as in Example 1.

[0079] (Example 12) In Example 12, the Zr / Ti ratio of the dielectric material was 0.06. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.01. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0080] (Example 13) In Example 13, the Zr / Ti ratio of the dielectric material was 0.10. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.01. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0081] (Comparative Example 1) In Comparative Example 1, the Zr / Ti ratio of the dielectric material was 0.01. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.01. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0082] (Comparative Example 2) In Comparative Example 2, the Zr / Ti ratio of the dielectric material was 0.02. The Ba / Ti ratio of the dielectric material was 1.003. No Eu oxide was added. Y2O3 was added to the dielectric material. The Y / Ti ratio, which is the ratio of the amount of Y to the amount of Ti, was 0.01. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0083] (Comparative Example 3) In Comparative Example 3, the Zr / Ti ratio of the dielectric material was 0.02. The Ba / Ti ratio of the dielectric material was 1.003. No Eu oxide was added. Ho₂O₃ was added to the dielectric material. The Ho / Ti ratio, which is the ratio of the amount of Ho to the amount of Ti, was 0.01. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0084] (Comparative Example 4) In Comparative Example 4, the Zr / Ti ratio of the dielectric material was 0.02. The Ba / Ti ratio of the dielectric material was 1.003. No Eu oxide was added. Dy2O3 was added to the dielectric material. The Dy / Ti ratio, which is the ratio of the amount of Dy to the amount of Ti, was 0.01. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0085] (Comparative Example 5) In Comparative Example 5, the Zr / Ti ratio of the dielectric material was 0.02. The Ba / Ti ratio of the dielectric material was 1.003. No Eu oxide was added. Tb4O7 was added to the dielectric material. The Tb / Ti ratio, which is the ratio of the amount of Tb to the amount of Ti, was 0.01. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0086] (Comparative Example 6) In Comparative Example 6, the Zr / Ti ratio of the dielectric material was 0.02. The Ba / Ti ratio of the dielectric material was 1.003. No Eu oxide was added. Gd2O3 was added to the dielectric material. The Gd / Ti ratio, which is the ratio of the amount of Gd to the amount of Ti, was 0.01. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0087] (Comparative Example 7) In Comparative Example 7, the Zr / Ti ratio of the dielectric material was 0.02. The Ba / Ti ratio of the dielectric material was 1.003. No Eu oxide was added. Nd2O3 was added to the dielectric material. The Nd / Ti ratio, which is the ratio of the amount of Nd to the amount of Ti, was 0.01. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0088] (Comparative Example 8) In Comparative Example 8, the Zr / Ti ratio of the dielectric material is 0.02. The Ba / Ti ratio of the dielectric material is 1.003. No Eu oxide is added. 11 Added to the dielectric material. The Pr / Ti ratio, which is the ratio of the amount of Pr to the amount of Ti, was 0.01. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0089] (Comparative Example 9) In Comparative Example 9, the Zr / Ti ratio of the dielectric material was 0.02. The Ba / Ti ratio of the dielectric material was 1.003. No Eu oxide was added. CeO was added to the dielectric material. The Ce / Ti ratio, which is the ratio of the amount of Ce to the amount of Ti, was 0.01. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0090] (Comparative Example 10) In Comparative Example 10, the Zr / Ti ratio of the dielectric material was 0.02. The Ba / Ti ratio of the dielectric material was 1.003. No Eu oxide was added. La2O3 was added to the dielectric material. The La / Ti ratio, which is the ratio of the amount of La to the amount of Ti, was 0.01. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0091] (Comparative Example 11) In Comparative Example 11, the Zr / Ti ratio of the dielectric material was 0.02. The Ba / Ti ratio of the dielectric material was 1.010. The Eu / Ti ratio of the dielectric material was 0.01. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0092] (Comparative Example 12) In Comparative Example 12, the Zr / Ti ratio of the dielectric material was 0.02. The Ba / Ti ratio of the dielectric material was 0.900. The Eu / Ti ratio of the dielectric material was 0.01. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0093] (Comparative Example 13) In Comparative Example 13, the Zr / Ti ratio of the dielectric material was 0.04. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.003. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0094] (Comparative Example 14) In Comparative Example 14, the Zr / Ti ratio of the dielectric material was 0.04. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.07. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0095] (Comparative Example 15) In Comparative Example 15, the Zr / Ti ratio of the dielectric material was 0.04. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.01. The Mn / Ti ratio of the dielectric material was 0.005. Ho₂O₃ was added. The Ho / Ti ratio, which is the ratio of the amount of Ho to the amount of Ti, was 0.01. Other conditions were the same as in Example 1.

[0096] (Comparative Example 16) In Comparative Example 16, the Zr / Ti ratio of the dielectric material was 0.04. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.01. No MnCO3 was added. The Mn / Ti ratio of the dielectric material was 0.00. Other conditions were the same as in Example 1.

[0097] (Comparative Example 17) In Comparative Example 17, the Zr / Ti ratio of the dielectric material was 0.04. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.01. The Mn / Ti ratio of the dielectric material was 0.07. Other conditions were the same as in Example 1.

[0098] (Comparative Example 18) In Comparative Example 18, the Zr / Ti ratio of the dielectric material was 0.12. The Ba / Ti ratio of the dielectric material was 1.003. The Eu / Ti ratio of the dielectric material was 0.01. The Mn / Ti ratio of the dielectric material was 0.005. Other conditions were the same as in Example 1.

[0099] (Analysis) For Examples 1-13 and Comparative Examples 1-18, the capacitance was measured respectively. And, the dielectric constant of the dielectric layer was calculated from the number of stacking layers, the cross area and the thickness of the dielectric layer. HALT (accelerated life test) was performed on each of Examples 1-13 and Comparative Examples 1-18 under high temperature and high electric field conditions of 125°C and 50V / μm. MTTF (Mean Time To Failure) was measured by measuring the time until the leakage current exceeded the threshold (1mA). And, it was determined whether Examples 1-13 and Comparative Examples 1-18 met the X5R performance. The results are shown in Tables 2 and 3.

[0100] [Table 2]

[0101]

[0102] [Table 3]

[0103]

[0104] When the dielectric constant of a sample was 1500 or greater, the sample was determined to be good (○). When the MTTF of a sample was 1000 min or greater, the sample was determined to be good (○). When the sample met the X5R performance, the sample was determined to be good (○). When the sample was determined to be good in all three judgments, the sample was determined to be overall good (○). When the sample was determined to be poor (×) in at least one of the three judgments, the sample was determined to be overall poor (×).

[0105] Examples 1-13 were rated as generally good (○). This is believed to be because, since the relationship of "0.02 ≤ Zr / Ti ratio ≤ 0.10" was satisfied, the relationship of "0.900 < Ba / Ti ratio < 1.010" was satisfied, the relationship of "0.005 ≤ Eu / Ti ratio ≤ 0.05" was satisfied, and the relationship of "0.0005 ≤ Mn / Ti ratio ≤ 0.05" was satisfied, a reliable material with a high dielectric constant and a stable structure was obtained.

[0106] Comparative Example 1 did not achieve a sufficient lifespan and did not achieve X5R performance. This is believed to be because the Zr / Ti ratio was 0.01, which prevented the formation of a core-shell structure and caused localized abnormal grain growth.

[0107] The MTTF of Comparative Example 2-10 was determined to be poor. This is believed to be because the core-shell in which Zr diffused into the shell did not achieve a long life due to the addition of rare earth elements other than Eu.

[0108] The MTTF of Comparative Example 11 was determined to be poor. This is believed to be because the Ba / Ti ratio was 1.010 and grain growth occurred.

[0109] The MTTF of Comparative Example 12 was determined to be poor. This is believed to be because the Ba / Ti ratio was 0.900, the amount of Ti was relatively large, and the effect of adding Zr was small.

[0110] The MTTF of Comparative Example 13 was determined to be poor. This is believed to be because the Eu / Ti ratio was 0.003, and the effect of adding Eu could not be fully achieved.

[0111] In Comparative Example 14, a sufficient lifespan was not achieved. This is believed to be because the Eu / Ti ratio was 0.07 and the amount of Eu was too large.

[0112] The MTTF of Comparative Example 15 was determined to be poor. This is believed to be because the amount of rare earth elements other than Eu was equal to the amount of Eu, and a sufficient lifespan was not achieved.

[0113] The MTTF of Comparative Example 16 was determined to be poor. This is believed to be because Mn was not added and sufficient insulation characteristics were not achieved.

[0114] The MTTF of Comparative Example 17 was determined to be poor. This is believed to be because the Mn / Ti ratio was 0.07 and the amount of Mn was too large.

[0115] The MTTF of Comparative Example 18 was determined to be poor. This is believed to be because the Zr / Ti ratio was 0.12, causing grain growth.

[0116] From the results of Examples 2-7, in terms of increasing MTTF, the Eu / Ti ratio is preferably 0.01 or more and 0.02 or less.

[0117] Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.

Claims

1. A stacked ceramic capacitor comprising: A laminated structure having a substantially rectangular parallelepiped shape and comprising alternately laminated dielectric layers and internal electrode layers, wherein the dielectric layers are mainly composed of BaTiO3 and the internal electrode layers are alternately exposed at two end faces of the laminated structure facing each other. wherein, in the capacitor portion where the internal electrode layers exposed on different end surfaces of the stacked structure face each other, a Zr / Ti ratio, which is a ratio of the amount of Zr to the amount of Ti, is 0.02 or more and 0.10 or less; wherein, in the capacitor portion, a Ba / Ti ratio, which is a ratio of the amount of Ba to the amount of Ti, is greater than 0.900 and less than 1.010, wherein, in the capacitor portion, a Eu / Ti ratio, which is a ratio of the amount of Eu to the amount of Ti, is 0.005 or more and 0.05 or less, wherein, in the capacitor portion, a Mn / Ti ratio, which is a ratio of the amount of Mn to the amount of Ti, is 0.0005 or more and 0.05 or less, and The total amount of one or more rare earth elements other than Eu is less than the amount of Eu.

2. The multilayer ceramic capacitor according to claim 1, wherein The dielectric layer in the capacitor portion does not include any rare earth element other than Eu.

3. The multilayer ceramic capacitor according to claim 1 or 2, in, At least one of the crystal grains of the dielectric layer in the capacitor portion has a core-shell structure, and In the core-shell structure, the concentration of Zr in the shell is higher than that in the core.

4. The multilayer ceramic capacitor according to claim 3, in, The shell includes Zr, and Wherein, the core does not include Zr.

5. The multilayer ceramic capacitor according to claim 3 or 4, in, The shell comprises Eu, and Wherein, the core does not include Eu.

6. The multilayer ceramic capacitor according to any one of claims 1 to 5, wherein The Zr / Ti ratio is 0.03 or more and 0.08 or less.

7. The multilayer ceramic capacitor according to any one of claims 1 to 5, wherein The Zr / Ti ratio is 0.04 or more and 0.06 or less.

8. The multilayer ceramic capacitor according to any one of claims 1 to 7, wherein The Ba / Ti ratio is 0.950 or more and less than 1.

010.

9. The multilayer ceramic capacitor according to any one of claims 1 to 7, wherein The Ba / Ti ratio is 1.000 or more and less than 1.

010.

10. The multilayer ceramic capacitor according to any one of claims 1 to 9, wherein The Eu / Ti ratio is 0.0075 or more and 0.03 or less.

11. The multilayer ceramic capacitor according to any one of claims 1 to 9, wherein The Eu / Ti ratio is 0.01 or more and 0.02 or less.

12. The multilayer ceramic capacitor according to any one of claims 1 to 11, wherein The Mn / Ti ratio is 0.001 or more and 0.02 or less.

13. The multilayer ceramic capacitor according to any one of claims 1 to 11, wherein The Mn / Ti ratio is 0.0015 or more and 0.01 or less.

14. The multilayer ceramic capacitor according to any one of claims 1 to 13, wherein The multilayer ceramic capacitor satisfies X5R characteristics.

15. The multilayer ceramic capacitor according to any one of claims 3 to 5, wherein When the major axis length of the particle diameter in the core-shell structure is "D" and the major axis length of the core diameter is "d", the d / D ratio is 0.3 or more and 0.9 or less.

16. A dielectric material comprising: BaTiO3 powder; and additive compounds, The Zr / Ti ratio, which is the ratio of the amount of Zr to the amount of Ti, is 0.02 or more and 0.10 or less. The Ba / Ti ratio, which is the ratio of the amount of Ba to the amount of Ti, is greater than 0.900 and less than 1.

010. The Eu / Ti ratio, which is the ratio of the amount of Eu to the amount of Ti, is 0.005 or more and 0.05 or less. The Mn / Ti ratio, which is the ratio of the amount of Mn to the amount of Ti, is 0.0005 or more and 0.05 or less, and The total amount of one or more rare earth elements other than Eu is less than the amount of Eu.

17. The dielectric material according to claim 16, wherein The Eu / Ti ratio is 0.0075 or more and 0.03 or less.

18. The dielectric material according to claim 16, wherein The Eu / Ti ratio is 0.01 or more and 0.02 or less.

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