Multilayer ceramic electronic component

Abstract

To provide a multilayer ceramic electronic component improved in a continuation rate of internal electrode layers.SOLUTION: A multilayer ceramic electronic component 100 comprises: dielectric layers 11 which are laminated in a lamination direction: an internal electrode (a first internal electrode layer 12a and a second internal electrode layer 12b) disposed between the dielectric layers which are adjacent in the lamination direction; and an intermediate region 40 which is disposed between the dielectric layer and the internal electrode layer. The dielectric layer contains a compound, which is expressed by a general formula: ABO3-α (0≤α≤1) and has a perovskite structure, and manganese. The internal electrode layer contains a base metal element and copper as a main component. The intermediate region contains manganese and copper. An average value of atomic number ratios in a content of manganese in the intermediate region is larger than an average value of atomic number ratios in a content of manganese in a first reference region which is a region of the dielectric layer separated from a second boundary by 2 nm or more to 5 nm or less.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a multilayer ceramic electronic component. [Background technology]

[0002] Multilayer ceramic electronic components have a structure in which dielectric layers and internal electrode layers are alternately stacked, and examples of multilayer ceramic electronic components include multilayer ceramic capacitors (MLCCs).

[0003] As electronic devices such as mobile phones become more multifunctional and performant, there is a demand for multilayer ceramic electronic components such as multilayer ceramic capacitors to be smaller and have higher capacitance. To meet these demands, multilayer ceramic electronic components are being required to have thinner dielectric layers and internal electrode layers and to have an increased number of layers. For this reason, research has been conducted to determine how to obtain desired characteristics for multilayer ceramic electronic components by thinning the dielectric layers and internal electrode layers.

[0004] For example, Patent Document 1 discloses a dielectric ceramic whose main component is BaTiO3-based and contains Li as a secondary component, and a multilayer ceramic capacitor having a dielectric ceramic layer made of the dielectric ceramic.

[0005] According to the dielectric ceramic disclosed in Patent Document 1, when used to form the dielectric ceramic layers of a multilayer ceramic capacitor, it is said that good life characteristics can be achieved even when the thickness of the dielectric ceramic layers is reduced to less than 1 μm. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-052964 Summary of the Invention [Problem to be solved by the invention]

[0007] However, there is a difference in melting point between the material of the internal electrode layer and the material of the dielectric layer, and the material of the internal electrode layer usually tends to densify faster. Therefore, when a laminate in which the dielectric green sheets that become the dielectric layers and the metal pastes that become the internal electrode layers are alternately arranged to form a predetermined shape is fired, the continuity rate of the internal electrode layers decreases, and there is a risk that the desired design specifications cannot be achieved. Furthermore, there is a risk that this tendency becomes more pronounced when the internal electrode layers, etc. are made thinner.

[0008] An object of the present disclosure is to provide a multilayer ceramic electronic component having an excellent continuity ratio of internal electrode layers. [Means for solving the problem]

[0009] The multilayer ceramic electronic component of the present disclosure comprises: a plurality of dielectric layers stacked along a first axis; a plurality of internal electrode layers each disposed between adjacent dielectric layers along the first axis; an intermediate region disposed between the dielectric layer and the internal electrode layer, The dielectric layer is a compound of the general formula ABO 3-α (0≦α≦1), containing a compound having a perovskite structure and manganese, the internal electrode layers contain a base metal element and copper as main components, the intermediate region contains manganese and copper; When 3D atom probe analysis was performed, a first boundary between the internal electrode layer and the intermediate region is set at a position where the atomic ratio of the oxygen content is 5 at %; When a second boundary, which is a boundary between the dielectric layer and the intermediate region, is defined as a position where the atomic ratio of the content of oxygen and the atomic ratio of the content of the base metal element as the main component are equal, a multilayer ceramic electronic component in which the average atomic percentage of the manganese content in the intermediate region is greater than the average atomic percentage of the manganese content in a first reference region, which is a region of the dielectric layer that is 2 nm or more and 5 nm or less away from the second boundary. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide a multilayer ceramic electronic component having an excellent continuity ratio of internal electrode layers. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a partial cross-sectional perspective view illustrating a multilayer ceramic capacitor according to one embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view illustrating a multilayer ceramic capacitor according to one embodiment of the present disclosure. [Figure 3] FIG. 3 is a cross-sectional view illustrating a multilayer ceramic capacitor according to one embodiment of the present disclosure. [Figure 4] FIG. 4 is a cross-sectional view illustrating details of an element body according to one embodiment of the present disclosure. [Figure 5] FIG. 5 is an explanatory diagram of a method for determining whether or not there is an intermediate region. [Figure 6] FIG. 6 is a flowchart of a method for manufacturing a multilayer ceramic capacitor according to one embodiment of the present disclosure. [Figure 7] FIG. 7 is a diagram illustrating a method for manufacturing a multilayer ceramic capacitor according to one embodiment of the present disclosure. [Figure 8] Figure 8 shows an example of the measurement results of three-dimensional atom probe analysis. [Figure 9] FIG. 9 is an explanatory diagram of a method for evaluating the continuity ratio of the internal electrode layers. DETAILED DESCRIPTION OF THE INVENTION

[0012] Embodiments of the present disclosure will be described in detail below, but the present disclosure is not limited thereto. In this specification and the drawings, components having substantially the same functional configurations may be designated by the same reference numerals to avoid redundant description. The drawings also show, where appropriate, mutually orthogonal X-, Y-, and Z-axes. The X-, Y-, and Z-axes define a fixed coordinate system fixed to a multilayer ceramic capacitor, which is an example of a multilayer ceramic electronic component. When the multilayer ceramic capacitor, which is an example of a multilayer ceramic electronic component, has an approximately rectangular parallelepiped outer shape, the X-, Y-, and Z-axes may correspond to the length, width, and height of the capacitor. Hereinafter, a multilayer ceramic electronic component of this embodiment will be described using a multilayer ceramic capacitor, which is an example of a multilayer ceramic electronic component.

[0013] [Multilayer ceramic electronic components] (1) Structure of multilayer ceramic electronic components FIG. 1 is a partial cross-sectional perspective view illustrating a multilayer ceramic capacitor 100. FIGS. 2 and 3 are cross-sectional views illustrating the multilayer ceramic capacitor. 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 an element body 10 having a substantially rectangular parallelepiped shape. Two opposing surfaces of the element body 10 are referred to as the top and bottom surfaces, and four surfaces connecting the top and bottom surfaces are referred to as side surfaces. Typically, the surface facing the circuit board when the multilayer ceramic capacitor is mounted on the circuit board is referred to as the bottom surface, but this is not limited to this. In the example illustrated in FIGS. 1 to 3, a first external electrode 20a and a second external electrode 20b are provided on two opposing side surfaces of the element body 10, namely, a first side surface 10a and a second side surface 10b (see FIG. 2). The first external electrode 20a extends from the first side surface 10a to the four adjacent surfaces. The second external electrode 20b extends from the second side surface 10b to four adjacent surfaces. However, the first external electrode 20a and the second external electrode 20b are spaced apart from each other. The external electrodes may be provided on any surface of the element body 10, not limited to the two opposing side surfaces.

[0014] The stacking direction in which the dielectric layers 11 and the internal electrode layers 12 are stacked is the first axis, and in Figures 1 to 3, the first axis, which is the stacking direction in which the dielectric layers 11 and the internal electrode layers 12 are stacked, is the Z axis, which is the direction in which the internal electrode layers face each other.

[0015] The axis perpendicular to the first axis, which is the stacking direction, is the second axis. In Figures 1 to 3, the second axis perpendicular to the first axis, which is the stacking direction, is the X-axis. The second axis is along the length direction of the element body 10, and is the axis along the direction in which the first side surface 10a and the second side surface 10b of the element body 10 face each other, and the direction in which the first external electrode 20a and the second external electrode 20b face each other.

[0016] The third axis is an axis perpendicular to the first axis, which is the stacking direction, and perpendicular to the second axis. The third axis is an axis along the width of the internal electrode layer 12. In Figures 1 to 3, the third axis, which is an axis perpendicular to the first axis, which is the stacking direction, and perpendicular to the second axis, is the Y axis, which is an axis along the direction in which the third side surface 10c and the fourth side surface 10d, which are the two side surfaces other than the first side surface 10a and the second side surface 10b, of the four side surfaces of the element body 10, face each other (see Figure 3). The X axis, Y axis, and Z axis are orthogonal to each other.

[0017] The stacking direction is not limited to the Z direction and can be any direction. Therefore, for example, the first axis, which is the stacking direction, may be the X axis in the X direction or the Y axis in the Y direction.

[0018] In this specification, for the purpose of explaining a general embodiment, figures illustrating a specific embodiment may be used, and the content described using the coordinate axis system used in the embodiment is applied to the general embodiment by replacing it with a general coordinate system in which the stacking direction is the first axis. For example, what is described as the X-axis, Y-axis, and Z-axis used in Figures 1 to 3 in a specific embodiment, where the stacking direction coincides with the Z-axis, can be replaced with the second axis, third axis, and first axis in the general embodiment.

[0019] The element body 10 has a configuration in which dielectric layers 11 containing a ceramic material that functions as a dielectric and internal electrode layers 12 are alternately stacked. The internal electrode layers 12 include a plurality of first internal electrode layers 12a and a plurality of second internal electrode layers 12b. The first internal electrode layers 12a and the second internal electrode layers 12b are alternately stacked. The edges of the first internal electrode layers 12a extend to the surface of the element body 10 on which the first external electrode 20a is provided, that is, the first side surface 10a in the examples of FIGS. 1 to 3. The edges of the second internal electrode layers 12b extend to the surface of the element body 10 on which the second external electrode 20b is provided, that is, the second side surface 10b in the examples of FIGS. 1 to 3. As a result, the first internal electrode layers 12a and the second internal electrode layers 12b are alternately electrically connected to the first external electrode 20a and the second external electrode 20b. Therefore, the multilayer ceramic capacitor 100 has a configuration in which capacitor units are stacked. In addition, in a laminate of dielectric layers 11 and internal electrode layers 12, the internal electrode layers 12 are arranged as the outermost layers in the lamination direction, and the outer surfaces of the laminate in the lamination direction, i.e., the upper and lower surfaces in the examples of FIGS. 1 to 3, are covered with cover layers 13. The cover layers 13 are mainly composed of a ceramic material. For example, the composition of the cover layers 13 may be the same as or different from that of the dielectric layers 11. Note that the configuration is not limited to that shown in FIGS. 1 to 3 as long as the first internal electrode layers 12a and the second internal electrode layers 12b are exposed in different regions on the surface of the laminate and are conductive to different external electrodes. The different regions on the surface of the laminate may be respective surface regions on opposing surfaces of the laminate, respective surface regions on adjacent surfaces of the laminate, or different surface regions on the same surface of the laminate. As long as the different external electrodes are spaced apart from each other, the first internal electrode layers 12a and the second internal electrode layers 12b may extend from the surfaces exposed in the surface region of the laminate to other surfaces.

[0020] As will be described in detail later, the element body 10 has a plurality of intermediate regions 40 (see FIG. 4) between the dielectric layers 11 and the internal electrode layers 12. The intermediate regions 40 are not shown in FIGS. 1 to 3.

[0021] The size of the multilayer ceramic capacitor 100 is not particularly limited, and may be, for example, 0.25 mm long, 0.125 mm wide, and 0.125 mm high; 0.4 mm long, 0.2 mm wide, and 0.2 mm high; 0.6 mm long, 0.3 mm wide, and 0.3 mm high; 1.0 mm long, 0.5 mm wide, and 0.5 mm high; 3.2 mm long, 1.6 mm wide, and 1.6 mm high; or 4.5 mm long, 3.2 mm wide, and 2.5 mm high. However, the above-listed sizes of the multilayer ceramic capacitor 100 are merely examples, and the multilayer ceramic capacitor is not limited to these sizes. The size of the multilayer ceramic capacitor 100 may be, for example, length > width ≥ height; width > length ≥ height; height > length ≥ width; or height > width ≥ length. Note that, for example, length represents the size in the X-axis direction, width represents the size in the Y-axis direction, and height represents the size in the Z-axis direction.

[0022] As described above, the multilayer ceramic capacitor 100 of this embodiment has a plurality of dielectric layers 11 stacked along the Z-axis, which is a first axis, and a plurality of internal electrode layers 12 arranged between adjacent dielectric layers 11 along the first axis. Furthermore, the multilayer ceramic capacitor 100 of this embodiment has an intermediate region 40 arranged between the dielectric layers 11 and the internal electrode layers 12. The dielectric layers 11, the internal electrode layers 12, and the intermediate region 40 will be described below. (2) Dielectric layer The dielectric layer 11 is a compound represented by the general formula ABO 3-α (0≦α≦1) and contains a compound having a perovskite structure and manganese. (2-1) Components contained in the dielectric layer (Compounds with perovskite structure) When a compound having a perovskite structure has a stoichiometric composition, α, which indicates the amount of deviation from the stoichiometric composition, is 0 and is represented by the general formula ABO3. In the compound having a perovskite structure represented by the above general formula, α may be greater than 0 and equal to or less than 1. In other words, the compound having a perovskite structure represented by the above general formula may have more oxygen deficiencies than the stoichiometric composition.

[0023] Compounds with a perovskite structure include barium titanate (BaTiO3), calcium zirconate (CaZrO3), calcium titanate (CaTiO3), strontium titanate (SrTiO3), magnesium titanate (MgTiO3), and BaTiO3, which forms a perovskite structure. 1-x-y Ca x Sr y Ti 1-z Zr z One or more types selected from O3 (0≦x≦1, 0≦y≦1, 0≦z≦1) and the like can be used.

[0024] Ba 1-x-y Ca x Sr y Ti 1-z Zr z O3 includes barium strontium titanate, barium calcium titanate, barium zirconate, barium titanate zirconate, calcium titanate zirconate, and barium calcium titanate zirconate. Note that any compound having a perovskite structure may contain oxygen vacancies.

[0025] The dielectric layer 11 preferably contains barium titanate as a compound having a perovskite structure, as this compound has particularly excellent dielectric properties. The dielectric layer 11 may contain barium titanate as a main component, or may be composed solely of barium titanate. Barium titanate has excellent dielectric properties, such as an extremely high dielectric constant and low dielectric loss. Therefore, when the dielectric layer 11 contains barium titanate as a compound having a perovskite structure, the capacitance of the multilayer ceramic capacitor 100 can be increased. In this specification, "contained as a main component" means that barium titanate is contained in the largest amount of the components contained.

[0026] Furthermore, the compound having a perovskite structure may be contained as a main component in the dielectric layer 11. For example, the dielectric layer 11 may contain 50 mol % or more, or 90 mol % or more of the compound having a perovskite structure. (manganese) The dielectric layer 11 can further contain manganese. Manganese may be contained in a simple state, or may form a compound with other elements.

[0027] The inclusion of manganese in the dielectric layer 11 can lower the sintering temperature of the dielectric layer 11. This allows the temperature to be lowered when firing a laminate of the dielectric green sheet that becomes the dielectric layer 11 and the metal paste that becomes the internal electrode layer 12, and the continuity rate of the internal electrode layer 12 can be increased.

[0028] The proportion of manganese contained in the dielectric layer 11 is not particularly limited, and it can be added and contained to the extent that an intermediate region, which will be described later, is formed. (Additives) The dielectric layer 11 may contain an additive as an optional component.

[0029] The additives that can be contained in the dielectric layer 11 are not particularly limited, and examples thereof include oxides containing one or more elements selected from zirconium (Zr), magnesium (Mg), molybdenum (Mo), vanadium (V), chromium (Cr), rare earth elements (scandium (Sc), cerium (Ce), neodymium (Nd), yttrium (Y), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), and ytterbium (Yb), oxides containing one or more elements selected from cobalt (Co), nickel (Ni), lithium (Li), boron (B), sodium (Na), potassium (K), and silicon (Si), and glasses containing one or more elements selected from cobalt, nickel, lithium, boron, sodium, potassium, and silicon. (2-2) Thickness of the dielectric layer The thickness of the dielectric layer 11 is not particularly limited, but from the viewpoint of miniaturizing the multilayer ceramic capacitor 100 while increasing the number of layers to increase the capacitance, it is preferably 1.0 μm or less, and more preferably 0.8 μm or less.

[0030] Although there is no particular limitation on the lower limit of the thickness of the dielectric layer 11, from the viewpoint of improving productivity and yield, the minimum thickness can be set to 2 to 4 times the average diameter of the dielectric material particles used. For example, if the average diameter of the dielectric material particles used is 0.1 μm, the lower limit of the thickness of the dielectric layer 11 can be set to 0.2 μm or more to 0.4 μm or more.

[0031] The particle size of the dielectric material particles can be the Heywood diameter (the diameter of a circle with an area equal to that of the dielectric material particle being evaluated) of the observed cross section. The average diameter, which is the average particle size of the dielectric material particles, can be the arithmetic mean value of the particle sizes of 50 to 200 arbitrarily selected dielectric material particles.

[0032] The thickness of the dielectric layer 11 is evaluated in a cross section including a first axis parallel to the stacking direction. For example, it is preferable to evaluate either a cross section including a second axis perpendicular to the stacking direction or a cross section including a third axis perpendicular to the stacking direction and perpendicular to the second axis, due to ease of polishing and measurement. The multilayer ceramic capacitor 100 is polished in the third axis direction for the former, and in the second axis direction for the latter. Five layers are selected from the center, top, and bottom of the exposed dielectric layers 11 in the first axis direction. If the number of dielectric layers 11 is even, six layers are selected for the center. The thickness of each selected dielectric layer is measured at three locations: the center, left, and right ends. The average of the measured thicknesses is defined as the thickness of each dielectric layer 11. The average thickness of all the selected and evaluated dielectric layers 11 can then be defined as the thickness of the dielectric layers 11 in the multilayer ceramic capacitor 100.

[0033] In the example shown in Figures 1 and 2, the first axis, which is the lamination direction, is the Z-axis direction, so this is an example in which the multilayer ceramic capacitor 100 is polished along the Y-axis, which is the third axis, to expose the XZ plane on which the dielectric layers 11 and the internal electrode layers 12 are laminated.

[0034] In this case, of the exposed XZ plane, five dielectric layers 11 are selected from the center along the Z axis, which is the first axis, and five dielectric layers 11 are selected from the top and bottom ends along the Z axis, which is the first axis. If the number of dielectric layers 11 is an even number, six layers may be selected from the center. In this case, the selected dielectric layers 11 are selected from within the capacitive section 14.

[0035] Then, for each of the selected dielectric layers 11, the thickness is measured along the X-axis, which is the second axis, at three locations that are ¼, ½, and ¾ of the length of the dielectric layer 11 along the X-axis from the end, and the average value is used as the thickness of the dielectric layer 11. The same procedure is used to measure the thickness of all of the selected dielectric layers 11, and the average value can be used as the thickness of the dielectric layer 11 in the evaluated multilayer ceramic capacitor 100.

[0036] The thickness of the dielectric layer 11 described above and the thickness of the internal electrode layer 12 described later are measured from a cross-sectional observation image or the like of the multilayer ceramic capacitor 100. Since the intermediate region 40 does not appear clearly on the outside, the thickness of the dielectric layer 11 described above and the thickness of the internal electrode layer 12 described above are measured based on the boundary between the dielectric layer 11 and the internal electrode layer 12, which can be visually confirmed. Therefore, the thickness of the dielectric layer 11 described above and the thickness of the internal electrode layer 12 described later also include the intermediate region 40. (3) Internal electrode layers (3-1) Components contained in the internal electrode layer 2, the region where the first internal electrode layer 12a connected to the first external electrode 20a and the second internal electrode layer 12b connected to the second external electrode 20b face each other is a region where capacitance is generated in the multilayer ceramic capacitor 100. Therefore, the region where capacitance is generated is referred to as a capacitance portion 14. In other words, the capacitance portion 14 is a region where adjacent internal electrode layers face each other across a dielectric layer 11 connected to different external electrodes.

[0037] The region where the first internal electrode layers 12a connected to the first external electrode 20a face each other in the stacking direction without the second internal electrode layer 12b connected to the second external electrode 20b intervening therebetween is referred to as the first end margin 15a. The region where the second internal electrode layers 12b connected to the second external electrode 20b face each other in the stacking direction without the first internal electrode layer 12a connected to the first external electrode 20a intervening therebetween is referred to as the second end margin 15b. Each end margin is a region where internal electrode layers connected to the same external electrode face each other in the stacking direction without the internal electrode layers connected to different external electrodes intervening therebetween. The first end margin 15a and the second end margin 15b are regions where internal electrode layers 12 with the same potential face each other and do not generate substantial capacitance.

[0038] The side margin 16 is a region provided outside the capacitive section 14 in a direction along the Y-axis in the example of Fig. 3, which is a third axis perpendicular to the stacking direction and perpendicular to the second axis. In other words, the side margin 16 is an outer region adjacent to the capacitive section 14 when viewed from the stacking direction, and is an outer region adjacent to the capacitive section 14 on the side where the internal electrode layer 12 is not drawn out. The side margin 16 is also a region that does not generate electrical capacitance.

[0039] According to the investigations of the inventors of the present invention, the dielectric layer 11 containing manganese can increase the continuity ratio of the internal electrode layer 12, and increasing the manganese content of the dielectric layer 11 particularly enhances this effect. However, in light of the characteristics required of multilayer ceramic capacitors in recent years, it was found that the effect of increasing the continuity ratio of the internal electrode layer 12 simply by having the dielectric layer 11 contain manganese is not sufficient. Therefore, the inventors of the present invention conducted further investigations and confirmed that when the internal electrode layer 12 contains copper, an intermediate region containing both manganese derived from the dielectric layer 11 and copper derived from the internal electrode layer 12 is formed between the internal electrode layer 12 and the dielectric layer. Note that in the intermediate region, the manganese derived from the dielectric layer 11 and the copper derived from the internal electrode layer 12 may be enriched, i.e., have a higher concentration or atomic ratio, than the dielectric layer 11 and the internal electrode layer 12, respectively. Therefore, the intermediate region 40 may simultaneously include a manganese-enriched portion derived from the dielectric layer 11 and a copper-enriched portion derived from the internal electrode layer 12.

[0040] According to the study of the present inventors, the multilayer ceramic capacitor has such an intermediate region, which makes it possible to particularly increase the continuity rate of the internal electrode layers 12.

[0041] Therefore, the internal electrode layer 12 can contain a base metal and copper as main components. The proportion of copper contained in the internal electrode layer 12 is not particularly limited, and can be added and contained to the extent that the above-mentioned intermediate region is formed. Details of the intermediate region will be described later.

[0042] The internal electrode layers 12 may contain, in addition to copper, components used in the internal electrode layers of multilayer ceramic capacitors. The internal electrode layers 12 may contain, as the main component, in particular, a base metal such as nickel (Ni), tin (Sn), tungsten (W), or an alloy containing one or more selected from the group of base metals, in other words, the largest component in terms of substance amount.

[0043] The internal electrode layers 12 preferably contain nickel, as this provides excellent electrical properties and allows costs to be reduced, and may contain nickel as a main component.

[0044] The main component of the first internal electrode layer 12a and the main component of the second internal electrode layer 12b may be the same or different. For example, the main component of both the first internal electrode layer 12a and the second internal electrode layer 12b may be nickel. (3-2) Continuity of the internal electrode layer The continuity rate of the internal electrode layers 12 is not particularly limited, but is preferably high, more preferably 75% or more, and even more preferably 80% or more, from the viewpoint of achieving the design capacity of the multilayer ceramic capacitor 100. The continuity rate of the internal electrode layers 12 can be 100% or less.

[0045] The method for evaluating the continuity ratio of the internal electrode layers 12 will be explained in the examples, and therefore the explanation will be omitted. (3-3) Thickness of the internal electrode layer The thickness of the internal electrode layer 12 is not particularly limited, but from the viewpoint of miniaturizing the multilayer ceramic capacitor 100 while increasing the number of layers to increase the capacitance, it is preferably 0.8 μm or less, and more preferably 0.6 μm or less.

[0046] The lower limit of the thickness of the internal electrode layer 12 is not particularly limited, but from the viewpoint of improving productivity and yield, it can be 0.4 μm or more when forming by printing a metal conductive paste by a printing method such as screen printing or gravure printing. For example, when forming by a thin film process such as sputtering or vapor deposition, it can be 0.1 μm or more, which is thinner than the thickness by the printing method.

[0047] The thickness of the internal electrode layer 12 is evaluated in a cross section including a first axis equal to the lamination direction, similar to the evaluation of the thickness of the dielectric layer 11. For example, it is preferable to evaluate in either a cross section that further includes a second axis set perpendicular to the lamination direction, or a cross section that further includes a third axis set perpendicular to the lamination direction and also perpendicular to the second axis, in terms of ease of polishing and measurement.

[0048] The multilayer ceramic capacitor 100 is polished so that the cross section can be seen, and five layers are selected from the central portion, upper end portion, and lower end portion of the exposed internal electrode layers 12 in the first axial direction. If the number of internal electrode layers 12 is an even number, six layers are selected from the central portion. Then, for each selected internal electrode layer 12, the thickness is measured at three locations: the central portion, the left end portion, and the right end portion, and the average value of the measured thicknesses is defined as the thickness of each internal electrode layer 12. Furthermore, the average value of the thicknesses of all the selected and evaluated internal electrode layers 12 can be defined as the thickness of the internal electrode layers 12 in the multilayer ceramic capacitor 100.

[0049] In the example shown in FIGS. 1 and 2, the first axis, which is the lamination direction, is the Z-axis direction, and therefore the multilayer ceramic capacitor 100 is polished along the Y-axis to expose the XZ plane where the dielectric layers 11 and the internal electrode layers 12 are laminated. In this case, of the XZ plane exposed by polishing, five internal electrode layers 12 located in the center along the Z-axis, which is the first axis, and five internal electrode layers 12 located at the top and bottom along the Z-axis, which is the first axis, are selected. Note that if the number of internal electrode layers 12 is an even number, six layers may be selected in the center. In this case, the selected internal electrode layers 12 are selected from within the capacitive section 14.

[0050] Then, for each of the selected internal electrode layers 12, the thickness is measured along the X-axis, which is the second axis, at three locations that are ¼, ½, and ¾ of the length of the internal electrode layer 12 along the X-axis from the end, and the average value is set as the thickness of the internal electrode layer 12. Using the same procedure, the thicknesses of all the selected internal electrode layers 12 are measured, and the average value of the thicknesses of all the selected and evaluated internal electrode layers 12 can be set as the thickness of the internal electrode layers 12 in the evaluated multilayer ceramic capacitor 100. (4) Intermediate Area 4 shows an enlarged view of a portion of the dielectric layer 11 and the internal electrode layer 12 of the element body 10. FIG. 4 is an enlarged view of, for example, region D in FIG.

[0051] The multilayer ceramic capacitor 100 has an intermediate region 40 containing manganese and copper, which is disposed between the dielectric layers 11 and the internal electrode layers 12. Because Fig. 4 is a schematic diagram, the intermediate region 40 is shown as a continuous layer with a constant thickness, but this is not intended to be limiting. The intermediate region 40 may be discontinuous, for example, and may have a thickness that varies depending on the location.

[0052] The presence or absence of the intermediate region 40 can be confirmed by elemental mapping using energy dispersive X-ray spectroscopy (EDX) analysis with a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM). The evaluation is performed on a cross section including a first axis parallel to the stacking direction. For example, it is preferable to evaluate either a cross section including a second axis perpendicular to the stacking direction or a cross section including a third axis perpendicular to the stacking direction and perpendicular to the second axis, because this facilitates polishing and measurement. In the example shown in FIGS. 1 and 2 , the first axis, which is the stacking direction, is the Z-axis. Therefore, the multilayer ceramic capacitor 100 is polished along the Y-axis, which is the third axis, to expose the XZ plane where the dielectric layers 11 and the internal electrode layers 12 are stacked. The sample is then sliced ​​to a thickness of approximately 0.1 μm, and the presence or absence of the intermediate region 40 can be confirmed by TEM / STEM-EDX analysis of the sample.

[0053] For example, from the element mapping results obtained, the presence or absence of the intermediate region 40 can be determined by observing the portion where the dielectric layer 11 and the internal electrode layer 12 are laminated.

[0054] When the above sample was subjected to TEM / STEM-EDX analysis, it was possible to confirm the distribution regions of elements contained in the dielectric material contained in the dielectric layer 11, as shown in Fig. 5(A). Fig. 5(A) shows a titanium distribution region 51 in the case where the dielectric layer 11 contains barium titanate as a dielectric material.

[0055] Furthermore, when the above sample is subjected to TEM / STEM-EDX analysis, it is possible to confirm the distribution region of the base metal element contained as the main component in the internal electrode layer 12, as shown in Fig. 5(B). Fig. 5(B) shows a nickel distribution region 52 in the case where the internal electrode layer 12 contains nickel as the base metal, as an example.

[0056] 5(C), in the element mapping result for copper, a copper distribution region 53 exists beyond a nickel distribution region 52, which is a distribution region of a base metal element contained as a main component in the internal electrode layer 12. In this case, it is observed that the copper distribution region 53 extends to a titanium distribution region 51, which is a distribution region of an element contained in the dielectric contained in the dielectric layer 11.

[0057] 5(D), in the element mapping result for manganese, a manganese distribution region 54 exists beyond a titanium distribution region 51, which is a distribution region of elements contained in the dielectric contained in the dielectric layer 11. In this case, it is observed that the manganese distribution region 54 extends to a nickel distribution region 52, which is a distribution region of base metal elements contained as a main component in the internal electrode layer 12.

[0058] In other words, when elemental mapping of copper and manganese is performed, if there is a region where the copper distribution region 53 and the manganese distribution region 54 overlap near the boundary where the dielectric layer 11 and the internal electrode layer 12 are stacked, it can be determined that an intermediate region 40 has been formed.

[0059] With regard to copper, a bias in the element distribution may be observed in the copper distribution region 53. For example, as shown in Fig. 5(C), in a portion of the copper distribution region 53 that is thought to correspond to the intermediate region 40, a concentrated portion 531 where the copper concentration is higher than in the nickel distribution region 52 may be confirmed by observation. In this way, in the region that corresponds to the intermediate region 40 shown in Fig. 5(C), the copper concentration may be higher than in the nickel distribution region 52 that is thought to correspond to the internal electrode layer 12.

[0060] With regard to manganese, a bias in the element distribution may be observed in the manganese distribution region 54. For example, as shown in Figure 5(D), in a portion of the manganese distribution region 54 that is thought to correspond to the intermediate region 40, a concentrated portion 541 where the manganese concentration is higher than in the titanium distribution region 51 can be confirmed by observation. In this way, the manganese concentration is higher in the region that corresponds to the intermediate region 40 shown in Figure 5(D) than in the titanium distribution region 51 that is thought to correspond to the dielectric layer 11.

[0061] When copper is not added to the internal electrode layer 12 as in the conventional case, there is no concentrated portion 541 in which the manganese concentration is higher than other portions in the manganese distribution region 54. Manganese, together with copper, forms a region that can be defined as the intermediate region 40 for the first time.

[0062] The intermediate region 40 may contain manganese and copper, and the state of the manganese and copper in the intermediate region 40 is not particularly limited. In the intermediate region 40, manganese and copper may form a compound, or manganese and copper may each form a compound with another element. Furthermore, in the intermediate region 40, at least one of manganese and copper may exist in an elemental state without forming a compound.

[0063] By including manganese in the dielectric layers 11, the sintering temperature of the dielectric layers 11 can be lowered, thereby increasing the continuity rate of the internal electrode layers 12. Increasing the continuity rate of the internal electrode layers 12 leads to an increase in the crossing area of ​​the internal electrodes, thereby increasing the actual capacitance of the multilayer ceramic capacitor 100. Increasing the manganese content of the dielectric layers 11 particularly enhances this effect.

[0064] However, according to the investigations of the inventors of the present invention, excessively increasing the manganese content of the dielectric layer 11 may result in a decrease in the DC bias characteristics (hereinafter simply referred to as "bias characteristics") of the capacitance of the multilayer ceramic capacitor 100.

[0065] In response to this, by adding copper to the internal electrode layer 12 and forming an intermediate region 40 containing copper between the internal electrode layer 12 and the dielectric layer 11, it is possible to prevent the base metal, which is the main component of the internal electrode layer 12, from diffusing toward the dielectric layer 11. This makes it possible to particularly increase the continuity rate of the internal electrode layer 12 and further reduce the deterioration of the bias characteristics. Furthermore, by setting the content ratio of manganese and copper contained in the intermediate region 40 within a predetermined range, it is possible to particularly increase the continuity rate of the internal electrode layer 12 and also improve the bias characteristics. (Composition of the intermediate region) The intermediate region 40 may contain manganese and copper, and its composition is not particularly limited. From the viewpoint of particularly improving the continuity rate and bias characteristics of the internal electrode layer 12, it is preferable that the elements are distributed similarly to the cases shown in Figures 5(A) to 5(D) when STEM-EDX analysis is performed. That is, it is preferable that the average atomic percentage of manganese contained in the intermediate region 40 is higher than that in the central portion in the thickness direction of the dielectric layer 11. It is also preferable that the average atomic percentage of copper contained in the intermediate region 40 is higher than that in the central portion in the thickness direction of the internal electrode layer 12.

[0066] When STEM-EDX analysis is performed, for example, among the regions where titanium and the like, which are elements contained in the dielectric contained in the dielectric layer 11, are distributed, the portion excluding the intermediate region 40 can be determined to be the region of the dielectric layer 11. Also, among the distribution regions of nickel and the like, which are distribution regions of base metal elements contained as main components in the internal electrode layers 12, the portion excluding the intermediate region 40 can be determined to be the region of the internal electrode layers 12.

[0067] The intermediate region 40 can be, for example, a region where a copper distribution region 53 and a manganese distribution region 54 overlap each other.

[0068] The central part of the dielectric layer 11 in the thickness direction means a position from the end of the dielectric layer 11 to half the thickness of the dielectric layer 11 in the thickness direction of the dielectric layer 11. Also, the central part of the internal electrode layer 12 in the thickness direction means a position from the end of the internal electrode layer 12 to half the thickness of the internal electrode layer 12 in the thickness direction of the internal electrode layer 12.

[0069] The average atomic percentage of each element in each region means the average concentration of each element determined by EDX, and is expressed in units of at%.

[0070] The above points are preferably evaluated by three-dimensional atom probe analysis, which can more accurately calculate the atomic number ratio of the content of elements at the measurement position.

[0071] FIG. 8 shows an example of a three-dimensional atom probe analysis performed along the Z axis, which is the first axis, from the dielectric layer 11 to the internal electrode layer 12.

[0072] 8, in the graph of the atomic percentage of the content of elements at the measurement positions obtained by three-dimensional atom probe analysis, a first boundary L81, which is the boundary between the internal electrode layer 12 and the intermediate region 40, is defined as the position where the atomic percentage of the content of oxygen is 5 at %, i.e., the straight line passing through point 81. This is because the internal electrode layer 12 contains almost no oxygen.

[0073] Also, a second boundary L82, which is the boundary between the dielectric layer 11 and the intermediate region 40, is defined as a position where the atomic percentage of the oxygen content and the atomic percentage of the base metal element content as the main component are equal, i.e., a straight line passing through point 82. Note that in Fig. 8, point 82 is the intersection point between a graph of the atomic percentage of the oxygen content resulting from the compound having a perovskite structure contained in the dielectric layer 11 and a graph of the atomic percentage of the element resulting from the base metal contained as the main component in the internal electrode layer 12, which is nickel in the case of Fig. 8.

[0074] In this case, the average atomic percentage of the manganese content in the intermediate region 40 is preferably greater than the average atomic percentage of the manganese content in the first reference region 83, which is a region of the dielectric layer 11 that is 2 nm to 5 nm away from the second boundary. In particular, the average atomic percentage of the manganese content in the intermediate region 40 is preferably 1.5 times or more the average atomic percentage of the manganese content in the first reference region 83.

[0075] Furthermore, when three-dimensional atom probe analysis is performed, it is preferable that the average value of the atomic ratio of the copper content in the intermediate region 40 is greater than the average value of the atomic ratio of the copper content in the second reference region 84, which is a region of the internal electrode layer 12 that is 2 nm to 5 nm away from the first boundary L81.

[0076] It is preferable from the viewpoint of particularly improving the bias characteristics of the multilayer ceramic capacitor 100 that the average atomic ratio (Mn) of the manganese content in the intermediate region 40 has a predetermined relationship with the average atomic ratio (Cu) of the copper content in the intermediate region 40.

[0077] Specifically, it is particularly preferable to satisfy the following formulas (1) and (2). Mn≦0.1574Cu+0.1010 (1) Mn≧0.12Cu-0.08 (2) The effects of manganese and copper contained in the intermediate region 40 will be described below.

[0078] Manganese benefits: During the manufacturing of the multilayer ceramic capacitor 100, the firing temperature can be lowered due to the effect of manganese, thereby improving the continuity of the internal electrode layers 12. Furthermore, at the end of sintering, excess manganese is discharged (diffused) from the dielectric layers 11 to the intermediate region 40, thereby preventing deterioration of the bias characteristics.

[0079] Copper's benefits: Copper can prevent the base metal, which is the main component of the internal electrode layer 12, from diffusing toward the dielectric layer 11. Therefore, the copper contained in the intermediate region 40 can particularly increase the continuity rate of the internal electrode layer 12, and further can reduce the deterioration of the bias characteristics.

[0080] When three-dimensional atom probe analysis is performed on a combination of manganese and copper, it is preferable that the average atomic percentage of the manganese content in the intermediate region 40 is 0.15 at% or more and 0.40 at% or less, and the average atomic percentage of the copper content is 0.32 at% or more and 3.15 at% or less.

[0081] When three-dimensional atom probe analysis is performed, the average atomic percentage of the manganese content in the intermediate region 40 is 1.5 times or more the average atomic percentage of the manganese content in the first reference region 83, which is a region of the dielectric layer 11 that is 2 nm or more and 5 nm or less away from the second boundary L82, and the average atomic percentage of the copper content in the intermediate region 40 may be, for example, 0.5 times or more and 3.0 times or less the atomic percentage of the copper content in the center of the thickness direction along the Z-axis, which is the first axis of the adjacent internal electrode layer 12.

[0082] When the atomic percentage of the element content in the intermediate region 40 is analyzed and quantified by energy dispersive X-ray (EDX) analysis using a transmission electron microscope (TEM) / scanning transmission electron microscope (STEM), the atomic percentage of the element content in portions of the sample other than the intermediate region 40 may also be included, potentially reducing analytical accuracy. This is because, when preparing a sample for TEM / STEM observation, the sample is thinned, and the backside of the sample may contain portions that are not the intermediate region 40, making it impossible to accurately evaluate the intermediate region 40. For example, when comparing two regions that clearly have large differences, using TEM / STEM-EDX analysis is not a problem. However, to accurately analyze the atomic percentage of the element content in the intermediate region 40, three-dimensional atom probe (3DAP) analysis is used to quantify the concentration.

[0083] The average atomic percentages of the copper and manganese contents in the intermediate region 40 can be evaluated by the procedure described in the examples, and therefore, the description thereof will be omitted here.

[0084] [Manufacturing method for multilayer ceramic capacitors] Next, a description will be given of a method for manufacturing the multilayer ceramic capacitor 100. Fig. 6 is a flowchart 60 illustrating an example of the method for manufacturing the multilayer ceramic capacitor 100. Fig. 7 is a diagram illustrating an example of the method for manufacturing the multilayer ceramic capacitor 100. (1) Raw material powder preparation process (S1) In the raw material powder preparation step, first, a dielectric material is prepared for forming the dielectric layer 11. The A-site elements and B-site elements contained in the dielectric layer 11 are usually ABO 3-α The dielectric layer 11 contains a sintered body of particles with a (0≦α≦1) structure. For example, barium titanate is a tetragonal compound with a perovskite structure and exhibits a high dielectric constant. Barium titanate can generally be obtained 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, including the solid-phase method, the sol-gel method, and the hydrothermal method. Any of these methods can be used in this embodiment.

[0085] In the raw material powder preparation step, manganese or a compound containing manganese can be added as an additive to the obtained ceramic raw material powder. A predetermined additive compound can also be added to the obtained ceramic raw material powder depending on the purpose. Examples of the additive compound include oxides containing one or more elements selected from zirconium (Zr), magnesium (Mg), molybdenum (Mo), vanadium (V), chromium (Cr), and rare earth elements (scandium (Sc), cerium (Ce), neodymium (Nd), yttrium (Y), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), and ytterbium (Yb)), or oxides containing one or more elements selected from cobalt (Co), nickel (Ni), lithium (Li), boron (B), sodium (Na), potassium (K), and silicon (Si), or glasses containing one or more elements selected from cobalt, nickel, lithium, boron, sodium, potassium, and silicon.

[0086] For example, a ceramic material can be prepared by wet-mixing a ceramic raw material powder with an additive containing manganese or a compound containing an additive compound, followed by drying and pulverization. For example, the ceramic material obtained as described above may be pulverized as necessary to adjust the particle size, or may be combined with a classification process to adjust the particle size. A dielectric material can be obtained by the above process. (2) Coating process (S2) Next, in the coating step, a binder such as polyvinyl butyral (PVB) resin, an organic solvent such as ethanol or toluene, and a plasticizer can be added to the obtained raw material powder and wet-mixed. Note that in the raw material powder preparation step (S1), a binder may be added at the same time as mixing the ceramic raw material powder and the like, and then wet-mixed.

[0087] In the coating process, the obtained slurry is used to coat a ceramic green sheet 71 on a substrate by, for example, a die coater method or a doctor blade method, and then dried. The substrate is, for example, a polyethylene terephthalate (PET) film. Figures illustrating the coating process are omitted. The ceramic green sheet 71 is an example of a dielectric green sheet. (3) Internal electrode layer formation process (S3) As described above, the first internal electrode layer 12a and the second internal electrode layer 12b can be mainly composed of base metals such as nickel (Ni), tin (Sn), tungsten (W), etc., or alloys containing these. The internal electrode layer 12 contains copper in addition to the above main components.

[0088] The main component of the first internal electrode layer 12a and the main component of the second internal electrode layer 12b may be the same or different. For example, the main component of both the first internal electrode layer 12a and the second internal electrode layer 12b may be nickel.

[0089] The metal conductive paste for forming the precursors of the first internal electrode layer 12a and the second internal electrode layer 12b can be prepared by kneading the main component selected from the above, copper, an organic binder, and a solvent. Copper may be added in a simple state or in a compound state. Also, an alloy containing a base metal element as a main component and copper may be used, or the surface of the base metal element as a main component or a compound containing the base metal element may be coated with copper or a copper compound before being added.

[0090] In the internal electrode layer forming process, as illustrated in FIG. 7(A), a metal conductive paste for forming the internal electrode layer containing an organic binder can be printed on the surface of a ceramic green sheet 71 by screen printing, gravure printing, or the like. Examples of the organic binder include ethyl cellulose (EC) and polyvinyl butyral (PVB) resin. This allows the first internal electrode layer pattern 72a for the first internal electrode layer 12a or the second internal electrode layer pattern 72b for the second internal electrode layer 12b to be disposed on the surface of the ceramic green sheet 71. The metal conductive paste can also contain various additives such as dispersants and ceramic particles as co-materials. The main component of the ceramic particles is not particularly limited, but is preferably the same as the main component ceramic of the dielectric layer 11. When ceramic particles are added as a co-material, they can be added during kneading of the metal conductive paste. The method for forming the internal electrode layer is not limited to printing; plating, vacuum deposition, sputtering, or CVD may also be used.

[0091] Alternatively, a dielectric pattern paste for the reverse pattern layer can be obtained by adding a binder such as an ethyl cellulose-based binder and an organic solvent such as a terpineol-based binder to the dielectric pattern material obtained in the raw material powder preparation step and kneading the mixture in a roll mill. As shown in Fig. 7(A), the dielectric pattern paste can be printed on a ceramic green sheet 71 in the peripheral area where the internal electrode layer pattern is not printed, thereby arranging the dielectric pattern 73 and filling in the step with the internal electrode layer pattern. The ceramic green sheet 71 on which the internal electrode layer pattern and the dielectric pattern 73 are printed is referred to as a lamination unit.

[0092] 7(B), the laminated units can be laminated so that the internal electrode layers and the dielectric layers alternate, and so that the edges of the internal electrode layers are alternately exposed at both end faces in the length direction of the dielectric layers and alternately drawn out to a pair of external electrodes (lamination process). Specifically, a ceramic green sheet 71 on which a first internal electrode layer pattern 72a and a dielectric pattern 73 are printed and a ceramic green sheet 71 on which a second internal electrode layer pattern 72b and a dielectric pattern 73 are printed are laminated in this order. For example, the number of laminated layers in the laminated unit can be set to 100 to 500. (4) Crimping process (S4) In the compression bonding step, a predetermined number of cover sheets, for example, 2 to 10 layers, can be laminated on the top and bottom of the laminate in which the lamination units are stacked, and then thermally compressed. (5) Singulation process (S5) In the singulation step, the pressure-bonded body is singulated to obtain singulated laminates. As the singulation method, any existing method such as dicing with a dicer or laser cutting can be used. (6) Firing process (S6) In the firing step, the individual laminated body can be degreased and fired. In the firing step, the degreasing treatment and the firing treatment can be performed consecutively or separately. The conditions for degreasing and firing are not particularly limited. For example, degreasing can be performed in a nitrogen atmosphere at 250°C or higher and 500°C or lower.

[0093] For example, when the oxygen partial pressure is 10 -12 atm over 10 -8 The firing can be carried out in a reducing atmosphere at a temperature range of 1100°C to 1350°C, for 5 minutes to 10 hours. -12 atm over 10 -10 The firing temperature may be preferably 1150°C or higher and 1350°C or lower. The firing time may be preferably 5 minutes or longer and shorter than 15 minutes. If necessary, after firing, a reoxidation treatment may be further performed in a nitrogen atmosphere at 600°C or higher and 1000°C or lower. (7) External electrode formation process (S7) In the external electrode formation process, a metal conductive paste for forming the external electrode layers, which contains a base metal such as nickel as its main component, a metal such as copper, and an organic binder, is applied by screen printing, dipping, or the like, and then baked. The method for forming the external electrodes is not limited to printing or dipping; plating, vacuum deposition, sputtering, or CVD may also be used. Alternatively, a conductive resin paste may be applied by screen printing, dipping, or the like, and the resin may be cured. If necessary, a copper, nickel, or tin layer may be formed by plating or the like. This forms the first external electrode 20a and the second external electrode 20b. The multilayer ceramic capacitor 100 is completed through the above steps.

[0094] The above steps are merely an example, and the method for manufacturing the multilayer ceramic capacitor of this embodiment is not limited to the above. For example, the external electrodes can be formed by providing a base layer for the external electrodes on the surface of the singulated laminate and firing the base layer for the external electrodes simultaneously with firing the ceramic. In this case, in the external electrode formation step after firing, a layer of copper, nickel, or tin is formed on the base layer by plating to complete the external electrodes.

[0095] [Other embodiments] Although the embodiments have been described in detail above, the present disclosure is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the claims.

[0096] For example, the above embodiment is applied to a multilayer ceramic capacitor having two terminal electrodes, but may also be applied to a multilayer ceramic capacitor having three or more terminals. [Example]

[0097] The present invention will be explained below by giving specific examples, but the present invention is not limited to these examples. (1) Evaluation method (1-1) Presence or absence of intermediate areas The presence or absence of the intermediate region 40 was confirmed by element mapping using energy dispersive X-ray (EDX) analysis with a scanning transmission electron microscope (STEM). For the evaluation, since the first axis, which is the lamination direction in Figures 1 and 2, is the Z-axis direction, the multilayer ceramic capacitor 100 was polished along the Y-axis, which is the third axis, as shown in Figures 1 and 2, to prepare a sample in which the XZ plane where the dielectric layers 11 and the internal electrode layers 12 were laminated was exposed. The sample was then sliced ​​to a thickness of about 0.1 µm, and the presence or absence of the intermediate region 40 was confirmed by STEM / EDX analysis.

[0098] Specifically, from the obtained element mapping results, the locations where the dielectric layers 11 and the internal electrode layers 12 were stacked were observed.

[0099] 5(C), in the element mapping result for copper, a copper distribution region 53 exists beyond a nickel distribution region 52, which is a distribution region of a base metal element contained as a main component in the internal electrode layer 12. In this case, it is observed that the copper distribution region 53 extends to a titanium distribution region 51, which is a distribution region of an element contained in the dielectric contained in the dielectric layer 11.

[0100] 5(D), in the element mapping result for manganese, a manganese distribution region 54 exists beyond a titanium distribution region 51, which is a distribution region of elements contained in the dielectric layer 11. In this case, it is observed that the manganese distribution region 54 extends to a nickel distribution region 52, which is a distribution region of base metal elements contained as a main component in the internal electrode layer 12.

[0101] That is, when elemental mapping of copper and manganese was performed, it was determined that an intermediate region 40 had been formed if a region where a copper distribution region 53 and a manganese distribution region 54 overlapped each other was found near the boundary where the dielectric layer 11 and the internal electrode layer 12 were stacked.

[0102] On the other hand, when at least one of the copper distribution region 53 and the manganese distribution region 54 could not be confirmed, or when there was no overlapping region between the copper distribution region 53 and the manganese distribution region 54, it was determined that an intermediate region had not been formed.

[0103] For the evaluation, the multilayer ceramic capacitor 100 was polished, and six internal electrode layers 12 located in the center along the Z axis, which is the first axis, and five internal electrode layers 12 located at the top and bottom along the Z axis, which is the first axis, were selected from the exposed XZ surface. Then, the above-mentioned observation of the vicinity of the interface between the selected internal electrode layers 12 and the dielectric layer 11 was carried out over the entire outer periphery of the internal electrode layers 12. The selected internal electrode layers 12 were selected from within the capacitance section 14.

[0104] In Table 1, in the "Intermediate Region" column, if the intermediate region 40 was confirmed at any of the locations evaluated, it is marked "Present," and if the intermediate region was not confirmed at any of the locations evaluated on the sample, it is marked "Absent." (1-2) Atomic ratio of manganese and copper content in the intermediate region The composition of the intermediate region 40 was analyzed using a three-dimensional atom probe (LEAP5000XS manufactured by AMETEK Corporation) along the Z-axis, which is the first axis, from the dielectric layer 11 to the internal electrode layer 12. The three-dimensional atom probe is a method for measuring three-dimensional atomic distribution by applying a high voltage to the sample, detecting ions that are field evaporated from the surface of the sample with a mass spectrometer, detecting each detected ion continuously in the depth direction, and arranging the ions in the order in which they were detected.

[0105] For the measurement, as shown in Figures 1 and 2, the multilayer ceramic capacitor 100 was polished along the Y axis to prepare a sample with the XZ plane where the dielectric layers 11 and the internal electrode layers 12 were laminated exposed, and the exposed XZ plane was evaluated.

[0106] An example of the measurement results is shown in Figure 8. As shown in Figure 8, by performing three-dimensional atom probe analysis, the atomic ratio of the content of each element contained in the dielectric layer 11 and the internal electrode layer 12 can be measured and calculated.

[0107] Among the measurement results, a first boundary L81, which is the boundary between the internal electrode layer 12 and the intermediate region 40, was defined as the position where the atomic percentage of the oxygen content is 5 at %, that is, the straight line passing through point 81.

[0108] In addition, a second boundary L82, which is the boundary between the dielectric layer 11 and the intermediate region 40, is defined as a position where the atomic ratio of the oxygen content and the atomic ratio of the base metal element content as the main component are equal, i.e., a straight line passing through point 82. The region sandwiched between the first boundary L81 passing through point 81 and the second boundary L82 passing through point 82 is defined as the intermediate region 40, and the content of the graph ranging from the first boundary L81 to the second boundary L82 is defined as the data for the intermediate region 40.

[0109] In Comparative Examples 1 to 6, an intermediate region containing both manganese and copper was not formed, but the intermediate region was defined in the same manner and evaluation was performed.

[0110] The average atomic percentages of the manganese and copper contents in the intermediate region 40 were then calculated. For the evaluation, the multilayer ceramic capacitor 100 was polished, and six dielectric layers located in the center along the Z axis (the first axis) of the exposed XZ surface were selected, and five dielectric layers located at the top and bottom along the Z axis (the first axis). Three-dimensional atom probe analysis was then performed from the selected dielectric layer 11 to the internal electrode layer 12 located above along the first axis, and the average values ​​of the manganese and copper contents relative to all elements detected in the intermediate region 40 were calculated. The selected dielectric layer 11 was selected from within the capacitive section 14.

[0111] The average manganese and copper content ratios within all the evaluated intermediate regions 40 are shown in Table 1 in the "Mn" and "Cu" columns under "Average atomic number ratio of element content in intermediate region," respectively.

[0112] In addition, the average atomic ratio of the manganese content in the first reference region 83, which is a region in the dielectric layer 11 that is 2 nm or more and 5 nm or less away from the second boundary L82, was calculated and shown in the column ``Atomic ratio of Mn in the first reference region'' in Table 1. (1-3) Continuity of internal electrode layers, determination of internal electrode layer continuity The continuity ratio of the internal electrode layers 12 can be calculated as follows. For evaluation, as shown in FIGS. 1 and 2, a multilayer ceramic capacitor 100 was polished along the Y-axis to prepare a sample in which the X-Z plane where the dielectric layers 11 and the internal electrode layers 12 were laminated was exposed. Next, the exposed X-Z plane was used as the observation surface, and a region C (see FIG. 2) included in the observation surface was observed with an SEM (scanning electron microscope). At this time, as shown in FIG. 9, a region that appears bright due to a contrast difference in the SEM image was identified as the electrode portion 91. Then, the length of this electrode portion 91 (in the illustrated example, the length along the X-axis direction) was measured, and the measured lengths L1, L2, ..., Ln were summed. The value obtained by dividing the sum of the lengths of the electrode portions 91 in region C by the length L0 of the measurement region (i.e., (L1 + L2 + ... Ln) / L0) can be defined as the continuity ratio of one first internal electrode layer 12a. The element body 10 includes a plurality of first internal electrode layers 12a, and the continuity ratio can vary depending on which of the plurality of first internal electrode layers 12a is focused on. Therefore, a plurality of different internal electrode layers 12 are selected, and the average of the continuity ratios calculated for each of the selected internal electrode layers 12 is defined as the continuity ratio of the internal electrode layers 12 in the multilayer ceramic capacitor 100. The conditions for selecting a plurality of different internal electrode layers 12 to be used for evaluation can be the same as the conditions for determining the thickness of the internal electrode layers 12.

[0113] For this reason, for the evaluation, the multilayer ceramic capacitor 100 was polished, and from the exposed XZ surface, six internal electrode layers 12 located in the center along the Z axis, which is the first axis, and five internal electrode layers 12 located at the top and bottom along the Z axis, which is the first axis, were selected. The selected internal electrode layers 12 were selected from within the capacitance section 14.

[0114] In measuring the continuity ratio of the internal electrode layers, 10 multilayer ceramic capacitors manufactured under the same conditions were evaluated in each experimental example, and the average value of the continuity ratios of the internal electrode layers of the 10 multilayer ceramic capacitors was used as the continuity ratio of the internal electrode layers of the multilayer ceramic capacitor in that experimental example.

[0115] The internal electrode layer continuity ratio was evaluated as ◯ when the obtained internal electrode layer continuity ratio was 75% or more, and as × when the obtained internal electrode layer continuity ratio was less than 75%. The evaluation results are shown in the "Internal electrode layer continuity ratio evaluation" column in Table 1. (1-4) DC bias characteristics, DC bias characteristics determination The capacitance change rate was calculated from the measured no-load capacitance C0 and the capacitance C3V when DC 3V was applied according to the following formula (1).

[0116] Capacitance change rate = (C3V - C0) / C0 × 100 (1) In measuring the DC bias characteristics, ten multilayer ceramic capacitors manufactured under the same conditions were evaluated for each experimental example, and the average value of the DC bias characteristics of the ten multilayer ceramic capacitors was used as the DC bias characteristic of the multilayer ceramic capacitor for that experimental example.

[0117] In the "DC bias characteristics" column of Table 1, the capacitance change rate in Comparative Example 2 is shown as a normalized value, with the rate being 100.

[0118] The DC bias characteristics were judged as follows: ◯ if the measured DC bias characteristics were 100 or more, △ if they were 85 or more but less than 100, and × if they were less than 85. (1-5) Overall Judgment In the overall judgment, if the internal electrode layer continuity judgment is ◯ and the DC bias characteristic judgment is ◯, it is judged as ◯, and if the internal electrode layer continuity judgment is ◯ and the DC bias characteristic judgment is △, it is judged as △. In addition, in the overall judgment, if at least one of the internal electrode layer continuity judgment or the DC bias characteristic judgment is ×, it is judged as ×. (2) Conditions for preparing samples [Example 1] A multilayer ceramic capacitor was manufactured according to the flow chart 60 shown in FIG.

[0119] Specifically, first, barium titanate powder, polyvinyl butyral (PVB) resin, a solvent, a plasticizer, glass powder containing SiO2 as a sintering aid, and manganese carbonate (MnCO3) were wet mixed to obtain a slurry (raw material powder preparation process).

[0120] The obtained slurry was applied onto a substrate film, and the slurry applied onto the substrate film was dried to obtain a ceramic green sheet (coating step).

[0121] Next, a copper-containing organometallic complex solution was added to and mixed with Ni powder, the main metallic element, to prepare a mixed powder. To the prepared mixed powder, binders such as ethyl cellulose (EC) or polyvinyl butyral (PVB) resin, a solvent, and a plasticizer were added and wet-mixed to obtain an internal electrode paste. If necessary, various auxiliary agents such as dispersants may be added in required amounts. Then, the internal electrode paste was printed on a partial area of ​​the surface of the ceramic green sheets to form an internal electrode layer pattern on each of the ceramic green sheets, thereby forming a laminate unit (internal electrode layer forming process). This laminate unit includes ceramic green sheets and internal electrode layer patterns formed on the surfaces of the ceramic green sheets.

[0122] Next, 500 laminate units were stacked to form a laminate, and this laminate was pressure-bonded and then cut into individual pieces to obtain chip-shaped green laminates (pressure-bonding step, cutting step).

[0123] Next, the chip-shaped green laminate was subjected to a degreasing treatment in a nitrogen atmosphere at 500°C.

[0124] After degreasing, a metal conductive paste containing a nickel-based metal filler, co-materials, binder, solvent, etc. was applied to the green laminate from both end faces to each side to form the base layer of the external electrodes, and then dried. The green laminate with the base layer of the external electrodes applied was placed in a firing furnace and fired. The firing temperature was 1300°C, and the firing time, which is the holding time at the firing temperature, was 10 minutes (firing process).

[0125] After firing, the first external electrode 20a and the second external electrode 20b were formed on the laminate by plating (external electrode forming step).

[0126] The obtained multilayer ceramic capacitor had a chip shape of 1.0 mm × 0.5 mm × 0.5 mm, a dielectric layer 11 thickness of 0.8 μm, an internal electrode layer 12 thickness of 0.6 μm, and the number of laminated layers was 500. The thicknesses of the dielectric layer 11 and the internal electrode layer 12 were evaluated by the procedure already described.

[0127] The obtained multilayer ceramic capacitor was evaluated as described above, and the evaluation results are shown in Table 1.

[0128] In addition, in Example 1 and Examples 2 to 14 described below, the average atomic ratio of the copper content in the intermediate region 40 was greater than the average atomic ratio of the copper content in the second reference region, which is a region of the internal electrode layer 12 that is 2 nm or more and 5 nm or less away from the first boundary L81. [Examples 2 to 14] Multilayer ceramic capacitors were manufactured using the same procedures as in Example 1, except that the amounts of manganese and copper added to the raw materials for the dielectric layers 11 and the internal electrode layers 12 were changed so that the average atomic percentages of the manganese and copper contents in the intermediate region were the values ​​shown in Table 1. The obtained multilayer ceramic capacitors were then evaluated as described above. The evaluation results are shown in Table 1. [Comparative Example 1] Manganese was not added to the raw materials for the dielectric layers 11, and the amount of copper added to the raw materials for the internal electrode layers 12 was changed so that the average value of the atomic ratio of the copper content in the intermediate region 40 would be the value shown in Table 1. Except for the above, a multilayer ceramic capacitor was manufactured using the same procedure as in Example 1. The obtained multilayer ceramic capacitor was also evaluated as described above. The evaluation results are shown in Table 1. [Comparative Examples 2 to 5] Copper was not added to the internal electrode layers 12, and the amount of manganese added to the raw materials for the dielectric layers 11 was changed so that the average atomic ratio of the manganese content in the intermediate region 40 would be the value shown in Table 1. Apart from the above, a multilayer ceramic capacitor was manufactured using the same procedure as in Example 1. The obtained multilayer ceramic capacitor was also evaluated as described above. The evaluation results are shown in Table 1. Comparative Example 6 The amounts of manganese and copper added to the raw materials for the dielectric layers 11 and the internal electrode layers 12 were changed so that the average atomic percentages of the manganese and copper contents in the intermediate region 40 would be the values ​​shown in Table 1, and the firing time after degreasing was set to 2 hours. Except for the above, multilayer ceramic capacitors were manufactured using the same procedure as in Example 1. The obtained multilayer ceramic capacitors were also evaluated as described above. The evaluation results are shown in Table 1.

[0129] [Table 1] According to the results shown in Table 1, in Examples 1 to 14 in which the intermediate region 40 is formed, the internal electrode layer continuity ratio is 75% or more, and it was confirmed that the continuity ratio of the internal electrode layer 12 is high.

[0130] According to Comparative Examples 2 to 5, as an effect of manganese, the continuity ratio of the internal electrode layers 12 increases as the average value of the atomic ratio of the manganese content in the intermediate region 40 increases, but the DC bias characteristics deteriorate. When the intermediate region 40 does not contain manganese as in Comparative Example 1, the continuity ratio of the internal electrode layers 12 becomes very low.

[0131] As in Comparative Example 6, when the average value of the atomic ratio of the manganese content in the intermediate region 40 is the same as the atomic ratio of the manganese content in the dielectric layer 11, the continuity ratio of the internal electrode layer 12 is low. This is thought to be because, although manganese becomes concentrated in the intermediate region 40 by firing, excessive firing, such as when the firing time is long, cancels out the effect of manganese in preventing over-sintering of the internal electrode layer 12.

[0132] In Examples 1 to 8, the average atomic ratio of the manganese content in the intermediate region 40 and the average atomic ratio of the copper content are particularly optimally combined, and the continuity rate and DC bias characteristics of the internal electrode layer 12 are both evaluated as ◯, i.e., excellent.

[0133] In Examples 9, 11, and 13, the average atomic percentage of the manganese content is low, but the average atomic percentage of the copper content is relatively high. It is believed that the excess copper diffuses into the dielectric layer 11 and affects the bias characteristics.

[0134] In Examples 10 and 12, the ratio of the average atomic percentage of the manganese content to the average atomic percentage of the copper content in the intermediate region 40 is small, which is thought to weaken the combined effect of manganese and copper, thereby affecting the bias characteristics.

[0135] In Example 14, the average atomic ratio of the manganese content in the dielectric layer 11 is considered to be excessive, which affects the bias characteristics.

[0136] When the average atomic percentage of the manganese content in the intermediate region is 0.15 at% or more and 0.40 at% or less, the optimal average atomic percentage of the copper content is 0.32 at% or more and 3.15 at% or less. This can be confirmed by the fact that the samples of Examples 1 to 9 also have excellent continuity and bias characteristics.

[0137] Although the details of this mechanism are not known, the following hypotheses are conceivable.

[0138] The simultaneous presence of manganese and copper in the intermediate region is thought to cause a reaction between the two, resulting in the formation of Mn-Cu-O oxide. This is thought to hinder mass transfer between the intermediate region and the dielectric layer, preventing a decrease in the manganese concentration in the dielectric layer due to manganese migration from the dielectric layer to the intermediate region, and preventing copper diffusion into the dielectric layer due to copper migration from the internal electrode layer through the intermediate region. Conversely, if there is an excess of either manganese or copper in the intermediate region, the excess manganese or copper that does not form Mn-Cu-O oxide will easily migrate to other layers, resulting in a decrease in the manganese concentration in the dielectric layer and copper diffusion into the dielectric layer. Therefore, it is thought that it is important to have appropriate amounts of manganese and copper in the intermediate region in order to particularly improve the continuity rate and bias characteristics of the internal electrodes.

[0139] Aspects of the present disclosure are, for example, as follows.

[0140] <1> a plurality of dielectric layers stacked along a first axis; a plurality of internal electrode layers each disposed between adjacent dielectric layers along the first axis; an intermediate region disposed between the dielectric layer and the internal electrode layer, The dielectric layer is a compound of the general formula ABO 3-α (0≦α≦1), containing a compound having a perovskite structure and manganese, the internal electrode layers contain a base metal element and copper as main components, the intermediate region contains manganese and copper; When 3D atom probe analysis was performed, a first boundary between the internal electrode layer and the intermediate region is set at a position where the atomic ratio of the oxygen content is 5 at %; When a second boundary, which is a boundary between the dielectric layer and the intermediate region, is defined as a position where the atomic ratio of the content of oxygen and the atomic ratio of the content of the base metal element as the main component are equal, a multilayer ceramic electronic component in which the average atomic percentage of the manganese content in the intermediate region is greater than the average atomic percentage of the manganese content in a first reference region, which is a region of the dielectric layer that is 2 nm or more and 5 nm or less away from the second boundary.

[0141] <2> When a three-dimensional atom probe analysis is performed, the average atomic ratio of the manganese content in the intermediate region is 1.5 times or more the average atomic ratio of the manganese content in the first reference region. <1> The multilayer ceramic electronic component according to claim 1.

[0142] <3> When a three-dimensional atom probe analysis is performed, the average value of the atomic ratio of the copper content in the intermediate region is greater than the average value of the atomic ratio of the copper content in a second reference region, which is a region of the internal electrode layer that is 2 nm or more and 5 nm or less away from the second boundary. <1> or <2> The multilayer ceramic electronic component according to claim 1.

[0143] <4> When a three-dimensional atom probe analysis is performed, the average atomic percentage of the manganese content in the intermediate region is 0.15 at% or more and 0.40 at% or less, and the average atomic percentage of the copper content is 0.32 at% or more and 3.15 at% or less. <1> from <3> 10. The multilayer ceramic electronic component according to claim 9, wherein

[0144] <5> The continuity rate of the internal electrode layer is 75% or more. <1> from <4> 10. The multilayer ceramic electronic component according to claim 9, wherein

[0145] <6> The internal electrode layers contain nickel. <1> from <5> 10. The multilayer ceramic electronic component according to claim 9, wherein

[0146] <7> the dielectric layer contains barium titanate as the compound having a perovskite structure; <1> from <6> 10. The multilayer ceramic electronic component according to claim 9, wherein [Explanation of symbols]

[0147] 100 Multilayer ceramic capacitors 10 Base 10a First side 10b Second side 11 Dielectric layer 12 Internal electrode layer 12a 1st internal electrode layer 12b Second internal electrode layer 13 Cover Layer 14 Capacity part 15a First End Margin 15b Second End Margin 16 Side Margin 20a 1st external electrode 20b 2nd external electrode C area D area 40 Intermediate area 51 Titanium distribution area 52 Nickel distribution area 53 Copper distribution area 531 Concentrated part 54 Manganese distribution area 541 Concentrated part 60 Flowchart S1 Raw material powder preparation process S2 Coating process S3 Internal electrode layer formation process S4 Crimping process S5 Singulation process S6 Firing process S7 External electrode formation process 71 Ceramic green sheet 72a First internal electrode layer pattern 72b Second internal electrode layer pattern 73 Dielectric Pattern 81 points 82 points 83 1st reference area 84 Second reference area L81 1st boundary L82 2nd boundary 91 Electrode section

Claims

1. a plurality of dielectric layers stacked along a first axis; a plurality of internal electrode layers each disposed between adjacent dielectric layers along the first axis; an intermediate region disposed between the dielectric layer and the internal electrode layer, The dielectric layer is formed of a material having the general formula ABO ３－α (0≦α≦1) and containing a compound having a perovskite structure and manganese, the internal electrode layers contain a base metal element and copper as main components, the intermediate region contains manganese and copper; When a three-dimensional atom probe analysis is performed, a first boundary between the internal electrode layer and the intermediate region is set at a position where the atomic ratio of the oxygen content is 5 at %; When a second boundary, which is a boundary between the dielectric layer and the intermediate region, is defined as a position where the atomic ratio of the content of oxygen and the atomic ratio of the content of the base metal element as the main component are equal, the average atomic percentage of the manganese content in the intermediate region is greater than the average atomic percentage of the manganese content in a first reference region, which is a region of the dielectric layer that is 2 nm or more and 5 nm or less away from the second boundary.

2. 2. The multilayer ceramic electronic component according to claim 1, wherein, when a three-dimensional atom probe analysis is performed, the average atomic percentage of the manganese content in the intermediate region is 1.5 times or more the average atomic percentage of the manganese content in the first reference region.

3. 2. The multilayer ceramic electronic component according to claim 1, wherein, when a three-dimensional atom probe analysis is performed, an average value of the atomic percentage of the copper content in the intermediate region is greater than an average value of the atomic percentage of the copper content in a second reference region, which is a region of the internal electrode layer that is 2 nm to 5 nm away from the first boundary.

4. 4. The multilayer ceramic electronic component according to claim 1, wherein, when a three-dimensional atom probe analysis is performed, the average atomic percentage of the manganese content in the intermediate region is 0.15 at% or more and 0.40 at% or less, and the average atomic percentage of the copper content in the intermediate region is 0.32 at% or more and 3.15 at% or less.

5. 4. The multilayer ceramic electronic component according to claim 1, wherein a continuity ratio of the internal electrode layers is 75% or more.

6. 4. The multilayer ceramic electronic component according to claim 1, wherein the internal electrode layers contain nickel.

7. 4. The multilayer ceramic electronic component according to claim 1, wherein the dielectric layers contain barium titanate as the compound having a perovskite structure.

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