Laminated ceramic electronic component

Abstract

Provided is a laminated ceramic electronic component having excellent continuity of internal electrode layers. The laminated ceramic electronic component includes: a plurality of dielectric layers laminated along a first axis; a plurality of internal electrode layers disposed between the dielectric layers adjacent to each other along the first axis; and an intermediate region disposed between the dielectric layer and the internal electrode layer, the dielectric layer containing manganese and a compound having a perovskite structure represented by the general formula ABO3-alpha (where 0 < = alpha < = 1), the internal electrode layer containing copper and a base metal element as a main component, the intermediate region containing manganese and copper, and the dielectric layer containing manganese and copper. The average value of the atomic ratio of the manganese content in the intermediate region is greater than the average value of the atomic ratio of the manganese content in the first reference region, and the first reference region is a region of the dielectric layer spaced from the second boundary by 2-5 nm.

Description

Technical Field

[0001] The present invention relates to a multilayer ceramic electronic component. Background Art

[0002] A multilayer ceramic electronic component has a structure in which dielectric layers and internal electrode layers are alternately stacked. Examples of multilayer ceramic electronic components include multilayer ceramic capacitors (MLCCs).

[0003] Multilayer ceramic electronic components, such as multilayer ceramic capacitors, are being driven by demands for miniaturization and increased capacity as electronic devices like mobile phones become increasingly multifunctional and performant. To meet these demands, multilayer ceramic electronic components are being required to have thinner dielectric and internal electrode layers and to increase the number of layers. Consequently, research has been ongoing to achieve the required properties by thinning dielectric and internal electrode layers.

[0004] For example, Patent Document 1 discloses a dielectric ceramic whose main component is BaTiO 3 and contains Li as a minor component, and a laminated ceramic capacitor having a dielectric ceramic layer composed of the dielectric ceramic.

[0005] According to the dielectric ceramic disclosed in Patent Document 1, when used to constitute a dielectric ceramic layer of a multilayer ceramic capacitor, excellent life characteristics can be imparted even when the dielectric ceramic layer is thinned to less than 1 μm.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2010-052964 Summary of the Invention

[0009] Technical problem to be solved by the invention

[0010] However, the melting point difference between the internal electrode layer material and the dielectric layer material generally leads to a tendency for the internal electrode layer material to densify more quickly. Consequently, firing a laminated body, where dielectric green sheets (which serve as dielectric layers) and metal paste (which serve as internal electrode layers) are alternately arranged in a predetermined shape, can reduce the continuity of the internal electrode layer and prevent the desired design features from being achieved. Furthermore, this tendency can become more pronounced when thinning the internal electrode layers.

[0011] An object of the present invention is to provide a multilayer ceramic electronic component having an excellent continuity rate of internal electrode layers.

[0012] Technical solutions to technical problems

[0013] The multilayer ceramic electronic component of the present invention has:

[0014] a plurality of dielectric layers stacked along a first axis (also referred to as a first axis);

[0015] a plurality of internal electrode layers respectively disposed between the dielectric layers adjacent to each other along the first axis; and

[0016] arranged in an intermediate region between the dielectric layer and the internal electrode layer,

[0017] The dielectric layer contains a dielectric having the general formula ABO 3-α A compound having a perovskite structure represented by and manganese, wherein 0≤α≤1,

[0018] The internal electrode layer contains base metal elements and copper as main components,

[0019] The intermediate region contains manganese and copper,

[0020] In the case of a three-dimensional atom probe analysis, when a first boundary between the internal electrode layer and the intermediate region is taken as a position where the atomic ratio of the oxygen content is 5 at %, and a second boundary between the dielectric layer and the intermediate region is taken as a position where the atomic ratio of the oxygen content is the same as the atomic ratio of the base metal element as the main component,

[0021] The average atomic ratio of the manganese content in the intermediate region is greater than the average atomic ratio of the manganese content in the first reference region, which is a region of the dielectric layer spaced from the second boundary by 2 nm to 5 nm.

[0022] Effects of the Invention

[0023] According to the present invention, a multilayer ceramic electronic component having an excellent continuity rate of internal electrode layers can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a partial cross-sectional perspective view illustrating a multilayer ceramic capacitor according to one embodiment of the present invention.

[0025] Figure 2 This is a cross-sectional view illustrating a multilayer ceramic capacitor according to one embodiment of the present invention.

[0026] Figure 3 This is a cross-sectional view illustrating a multilayer ceramic capacitor according to one embodiment of the present invention.

[0027] Figure 4This is a cross-sectional view illustrating details of a main body (also referred to as a “body”) according to one embodiment of the present invention.

[0028] Figure 5 This is an explanatory diagram of a method for determining the presence or absence of an intermediate region.

[0029] Figure 6 This is a flowchart of a method for manufacturing a multilayer ceramic capacitor according to one embodiment of the present invention.

[0030] Figure 7 1 and 2 are views illustrating a method for manufacturing a multilayer ceramic capacitor according to one embodiment of the present invention.

[0031] Figure 8 This is an example of the measurement results of 3D atom probe analysis.

[0032] Figure 9 It is an explanatory diagram of a method for evaluating the continuity rate of the internal electrode layer.

[0033] Description of Reference Signs

[0034] 100-layer ceramic capacitor

[0035] 10 main body

[0036] 10a First side

[0037] 10b Second side

[0038] 11 Dielectric layer

[0039] 12 internal electrode layers

[0040] 12a First internal electrode layer

[0041] 12b Second internal electrode layer

[0042] 13 Covering layer

[0043] 14 Capacitor

[0044] 15a first end edge

[0045] 15b Second end edge

[0046] 16 side edges

[0047] 20a first external electrode

[0048] 20b second external electrode

[0049] Area C

[0050] D area

[0051] 40 middle area

[0052] 51 Distribution area of ​​titanium

[0053] 52 Nickel distribution area

[0054] 53 Copper distribution area

[0055] 531 Thickening section (also called "thickening section")

[0056] 54 Distribution of manganese

[0057] 541 thickening unit

[0058] 60 Flowchart

[0059] S1 Raw material powder preparation process

[0060] S2 coating process

[0061] S3 Internal electrode layer forming process

[0062] S4 crimping process

[0063] S5 singulation process

[0064] S6 firing process

[0065] S7 External electrode forming process

[0066] 71 ceramic green sheets

[0067] 72a first internal electrode layer pattern

[0068] 72b second internal electrode layer pattern

[0069] 73 dielectric pattern

[0070] 81 points

[0071] 82 points

[0072] 83 First benchmark area

[0073] 84 Second benchmark area

[0074] L81 First Boundary

[0075] L82 Second Boundary

[0076] 91 electrode unit. DETAILED DESCRIPTION

[0077] Hereinafter, the embodiments of the present invention will be described in detail, but the present invention is not limited thereto. In addition, in this specification and the accompanying drawings, for components having substantially the same functional structure, repeated descriptions are sometimes omitted by marking the same figure marks. In addition, in the accompanying drawings, mutually orthogonal X-axis, Y-axis and Z-axis are appropriately represented. The X-axis, Y-axis and Z-axis are used to define a fixed coordinate system, which is fixed for a stacked ceramic capacitor as an example of a stacked ceramic electronic component. When the outer shape of a stacked ceramic capacitor as an example of a stacked ceramic electronic component is a roughly rectangular parallelepiped, the X-axis, Y-axis and Z-axis can be equivalent to its length, width and height. Hereinafter, a stacked ceramic capacitor as an example of a stacked ceramic electronic component is used to illustrate the stacked ceramic electronic component of this embodiment.

[0078] [Multilayer ceramic electronic components]

[0079] (1) Regarding the structure of multilayer ceramic electronic components

[0080] Figure 1 FIG. 1 is a partial cross-sectional perspective view illustrating a multilayer ceramic capacitor 100 . Figure 2 and Figure 3 is a cross-sectional view illustrating a multilayer ceramic capacitor. Figure 2 It is along Figure 1 Cross-section view along line AA. Figure 3 It is along Figure 1 The cross-sectional view of line BB in FIG. Figures 1 to 3 As shown, the multilayer ceramic capacitor 100 includes a body 10 having a substantially rectangular parallelepiped shape. In the body 10, two opposing surfaces are referred to as an upper surface and a lower surface, and four surfaces connecting the upper surface and the lower surface are referred to as side surfaces. Generally, when the multilayer ceramic capacitor is mounted on a circuit board, the surface on the circuit board side is referred to as the lower surface, but this is not limited to this. Figures 1 to 3 In the example of the main body 10, the first side surface 10a and the second side surface 10b (refer to Figure 2 ) are provided with a first external electrode 20a and a second external electrode 20b. The first external electrode 20a extends from the first side surface 10a to the four adjacent sides. The second external electrode 20b extends from the second side surface 10b to the four adjacent sides. However, the first external electrode 20a and the second external electrode 20b are separated from each other. As long as the external electrodes are provided on the surface of the main body 10, they are not limited to being provided on two opposite side surfaces.

[0081] The stacking direction of the dielectric layer 11 and the internal electrode layer 12 is the first axis. Figures 1 to 3 In FIG, the stacking direction of the dielectric layer 11 and the internal electrode layer 12, that is, the first axis is the Z axis, which is the direction in which the internal electrode layers are opposite to each other.

[0082] The axis perpendicular to the first axis as the stacking direction (i.e., the first axis along the stacking direction) is the second axis (also referred to as the second axis). Figures 1 to 3 The second axis, which is perpendicular to the first axis, which is the stacking direction, is the X-axis. The second axis is along the length of the main body 10 and is along the direction in which the first side surface 10a and the second side surface 10b of the main body 10 oppose each other, and along the direction in which the first external electrode 20a and the second external electrode 20b oppose each other.

[0083] The axis perpendicular to the first axis as the stacking direction and perpendicular to the second axis is the third axis (also referred to as the third axis). The third axis is an axis along the width of the internal electrode layer 12. Figures 1 to 3 The third axis, which is perpendicular to the first axis and the second axis, which is the stacking direction, is the Y axis, which is an axis along the direction in which two sides other than the first side 10a and the second side 10b of the four sides of the main body 10, namely the third side 10c and the fourth side 10d, are opposite to each other (see Figure 3 ). The X-axis, Y-axis, and Z-axis are orthogonal to each other.

[0084] The stacking direction is not limited to the Z direction, but may be any direction. Therefore, for example, the first axis as the stacking direction may be the X-axis in the X direction or the Y-axis in the Y direction.

[0085] In this application, in order to explain general embodiments, a figure illustrating a specific embodiment is sometimes used. However, the content described using the coordinate axis system used in one embodiment can be replaced with a general coordinate system with the stacking direction as the first axis in general embodiments. For example, as a specific embodiment, when the stacking direction is consistent with the Z direction, Figures 1 to 3 The contents described as the X-axis, Y-axis, and Z-axis may be replaced with the second axis, the third axis, and the first axis in a general embodiment.

[0086] The main body 10 has a structure in which dielectric layers 11 made of 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 end edges of the first internal electrode layers 12a are drawn out to the surface of the main body 10 provided with the first external electrode 20a. Figures 1 to 3 In the example, the first side surface 10a is provided. The edge of the second internal electrode layer 12b is led out to the surface of the main body 10 provided with the second external electrode 20b. Figures 1 to 3In the example, the second side surface 10b is provided. Thus, the first internal electrode layer 12a and the second internal electrode layer 12b are alternately connected to the first external electrode 20a and the second external electrode 20b. Therefore, the multilayer ceramic capacitor 100 has a structure in which capacitor units are stacked. In addition, in the stack of dielectric layers 11 and internal electrode layers 12, the internal electrode layer 12 is provided on the outermost layer in the stacking direction, and the outer side surface (in the stacking direction) of the stack is provided. Figures 1 to 3 The first internal electrode layer 12a and the second internal electrode layer 12b are exposed in different areas of the surface of the laminate and are electrically connected to different external electrodes. Figures 1 to 3 The different regions on the surface of the laminate may be surface regions on opposing sides of the laminate, surface regions on adjacent sides of the laminate, or different surface regions on the same side of the laminate. If different external electrodes are spaced apart from each other, the first and second internal electrode layers 12a, 12b may each extend from the side exposed in the surface region of the laminate to the other side.

[0087] The main body 10 has a plurality of intermediate regions 40 between the dielectric layer 11 and the internal electrode layer 12 (see Figure 4 ), details will be given later. Figures 1 to 3 , the description of the middle region 40 is omitted.

[0088] The dimensions of the multilayer ceramic capacitor 100 are not particularly limited. For example, the multilayer ceramic capacitor 100 may be formed with a length of 0.25 mm, a width of 0.125 mm, and a height of 0.125 mm; a length of 0.4 mm, a width of 0.2 mm, and a height of 0.2 mm; a length of 0.6 mm, a width of 0.3 mm, and a height of 0.3 mm; a length of 1.0 mm, a width of 0.5 mm, and a height of 0.5 mm; a length of 3.2 mm, a width of 1.6 mm, and a height of 1.6 mm; or a length of 4.5 mm, a width of 3.2 mm, and a height of 2.5 mm. However, the dimensions of the multilayer ceramic capacitor 100 listed above are merely examples, and the multilayer ceramic capacitor is not limited to the above dimensions. The dimensions of the multilayer ceramic capacitor 100 may be, for example, length>width≥height, width>length≥height, height>length≥width, or height>width≥length. In addition, for example, length represents the dimension in the X-axis direction, width represents the dimension in the Y-axis direction, and height represents the dimension in the Z-axis direction.

[0089] As described above, the multilayer ceramic capacitor 100 of this embodiment includes a plurality of dielectric layers 11 stacked along the Z-axis, which serves as a first axis, and a plurality of internal electrode layers 12 disposed between adjacent dielectric layers 11 along the first axis. Furthermore, the multilayer ceramic capacitor 100 of this embodiment includes an intermediate region 40 disposed 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 are described below.

[0090] (2) Regarding the dielectric layer

[0091] The dielectric layer 11 contains a dielectric having the general formula ABO 3-α A compound having a perovskite structure represented by (0≤α≤1) and manganese.

[0092] (2-1) Components contained in the dielectric layer

[0093] (Compounds having a perovskite structure)

[0094] In the case of a stoichiometric composition, a compound having a perovskite structure, α, which indicates the amount of deviation from the stoichiometric composition, is 0, and is represented by the general formula ABO3. The compound having a perovskite structure represented by the above general formula may have α greater than 0 and less than 1. That is, the compound having a perovskite structure represented by the above general formula may have oxygen vacancies compared to the stoichiometric composition.

[0095] As a compound having a perovskite structure, one can use a compound selected from barium titanate (BaTiO3), calcium zirconate (CaZrO3), calcium titanate (CaTiO3), strontium titanate (SrTiO3), magnesium titanate (MgTiO3), BaTiO3, which forms a perovskite structure, and 1-x- y Ca x Sr y Ti 1-z Zr z One or more of O3 (0≤x≤1, 0≤y≤1, 0≤z≤1), etc.

[0096] Ba 1-x-y Ca x Sr y Ti 1-z Zr z O3 is barium strontium titanate, barium calcium titanate, barium zirconate, barium zirconate titanate, calcium zirconate titanate, barium calcium zirconate titanate, etc. However, any material of the compound having a perovskite structure may contain oxygen vacancies.

[0097] Dielectric layer 11 has particularly excellent dielectric properties, and therefore preferably contains barium titanate as a compound having a perovskite structure. Alternatively, it may contain barium titanate as a main component, or it 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, by including barium titanate as a compound having a perovskite structure in dielectric layer 11, the electrostatic capacitance (electrostatic capacitance) of multilayer ceramic capacitor 100 can be increased. In this specification, "containing as a main component" means that the component contained is the largest by mass.

[0098] Furthermore, the dielectric layer 11 may contain a compound having a perovskite structure as a main component. For example, the dielectric layer 11 may contain 50 mol % or more of the compound having a perovskite structure, or 90 mol % or more of the compound having a perovskite structure.

[0099] (manganese)

[0100] Dielectric layer 11 may further contain manganese. Manganese may be contained in a simple substance or in the form of a compound with other elements.

[0101] The inclusion of manganese in the dielectric layer 11 reduces the sintering temperature of the dielectric layer 11. This reduces the temperature at which the laminate of the dielectric green sheet forming the dielectric layer 11 and the metal paste forming the internal electrode layer 12 is fired, thereby increasing the continuity of the internal electrode layer 12.

[0102] The ratio of manganese contained in dielectric layer 11 is not particularly limited, and it may be added and contained to such an extent that an intermediate region described later is formed.

[0103] (Additives)

[0104] The dielectric layer 11 may contain any component as an additive.

[0105] The additives that the dielectric layer 11 can contain are not particularly limited, and examples 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)), 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 glass containing one or more elements selected from cobalt, nickel, lithium, boron, sodium, potassium and silicon.

[0106] (2-2) Regarding the thickness of the dielectric layer

[0107] The thickness of dielectric layer 11 is not particularly limited, but is preferably 1.0 μm or less, and more preferably 0.8 μm or less, for example, from the viewpoint of miniaturizing multilayer ceramic capacitor 100 and increasing the number of layers to increase capacitance.

[0108] The lower limit of the thickness of dielectric layer 11 is not particularly limited. From the perspective 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 dielectric layer 11 can be 0.2 μm to 0.4 μm.

[0109] The particle size of the dielectric material particles can be the Heywood diameter (the diameter of a circle having an area equal to the area of ​​the dielectric material particles being evaluated) in the observed cross section. The average diameter, which is the average value of the particle sizes of the dielectric material particles, can be the arithmetic mean of the particle sizes of 50 or more and 200 or less randomly selected dielectric material particles.

[0110] When evaluating the thickness of dielectric layer 11, a cross section including the first axis along the stacking direction is used for evaluation. For example, for ease of polishing and measurement, it is preferable to evaluate using either a cross section also including a second axis perpendicular to the stacking direction or a cross section also including a third axis perpendicular to the stacking direction and perpendicular to the second axis. In the former, the multilayer ceramic capacitor 100 is polished in the direction of the third axis, while in the latter, the multilayer ceramic capacitor 100 is polished in the direction of the second axis. Five layers are selected from the center, top, and bottom of the exposed dielectric layer 11 along the first axis. If the number of dielectric layers 11 is even, six layers are selected from the center. Within each selected dielectric layer, the thickness is measured at three locations: the center, the left edge, and the right edge. The average of these measured thicknesses is used as the thickness of each dielectric layer 11. Furthermore, the average thickness of all selected and evaluated dielectric layers 11 can be used as the thickness of the dielectric layer 11 in the multilayer ceramic capacitor 100.

[0111] exist Figure 1 、 Figure 2 In the example shown, since the first axis along the stacking direction is the Z axis, the multilayer ceramic capacitor 100 is polished along the Y axis as the third axis to expose the XZ plane where the dielectric layers 11 and the internal electrode layers 12 are stacked.

[0112] In this case, in the exposed XZ plane, five dielectric layers 11 are selected at the center along the first axis, i.e., the Z axis, and five dielectric layers 11 are selected at the upper and lower ends along the first axis, i.e., the Z axis. Furthermore, if the number of dielectric layers 11 is even, six dielectric layers may be selected at the center. In this case, the selected dielectric layers 11 are selected from within the capacitor portion 14.

[0113] Furthermore, for each selected dielectric layer 11, the thickness is measured at three locations along the second axis, i.e., the X-axis, at intervals of 1 / 4, 1 / 2, and 3 / 4 of the length of the dielectric layer 11 along the X-axis from the end, and the average value thereof is used as the thickness of the dielectric layer 11. By measuring the thickness of all selected dielectric layers 11 in the same procedure, the thickness of the dielectric layer 11 in the multilayer ceramic capacitor 100 can be evaluated using the average value.

[0114] The thickness of the dielectric layer 11 and the thickness of the internal electrode layer 12 (described later) are measured from, for example, a cross-sectional image of the multilayer ceramic capacitor 100. Since the intermediate region 40 is not clearly visible in appearance, the thickness of the dielectric layer 11 and the internal electrode layer 12 are measured based on the visually observable boundary between the dielectric layer 11 and the internal electrode layer 12. Therefore, the thickness of the dielectric layer 11 and the thickness of the internal electrode layer 12 (described later) also include the intermediate region 40.

[0115] (3) Internal electrode layer

[0116] (3-1) Components contained in the internal electrode layer

[0117] like Figure 2 In the illustrated example, 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 the region where capacitance (i.e., capacitance) is generated in the multilayer ceramic capacitor 100. Therefore, the region where capacitance is generated is referred to as the capacitor portion 14. Specifically, the capacitor portion 14 is the region where adjacent internal electrode layers connected to different external electrodes face each other across the dielectric layer 11.

[0118] The region where the first internal electrode layers 12a connected to the first external electrode 20a face each other in the stacking direction without interposing the second internal electrode layer 12b connected to the second external electrode 20b is referred to as the first end edge 15a. Furthermore, the region where the second internal electrode layers 12b connected to the second external electrode 20b face each other in the stacking direction without interposing the first internal electrode layer 12a connected to the first external electrode 20a is referred to as the second end edge 15b. Each end edge is a region where internal electrode layers connected to the same external electrode face each other in the stacking direction without interposing internal electrode layers connected to different external electrodes. The first end edge 15a and the second end edge 15b are regions where internal electrode layers 12 having the same potential face each other, and are regions where substantially no capacitance is generated.

[0119] The side edge 16 is in a third axis perpendicular to the stacking direction and perpendicular to the second axis. Figure 3 In the example shown in FIG, the side edge 16 is an area provided outside the capacitor section 14 in the direction along the Y-axis. Specifically, the side edge 16 is an area outside the capacitor section 14 when viewed in the stacking direction, and is an area outside the capacitor section 14 on the side where the internal electrode layer 12 is not extended. The side edge 16 is also an area where no capacitance is generated.

[0120] According to the inventors' research, the inclusion of manganese in dielectric layer 11 can improve the continuity of internal electrode layer 12, and this effect is particularly pronounced by increasing the manganese content in dielectric layer 11. However, given the characteristics required of multilayer ceramic capacitors in recent years, simply including manganese in dielectric layer 11 is insufficient to improve the continuity of internal electrode layer 12. Therefore, the inventors conducted further research and confirmed that the inclusion of copper in internal electrode layer 12 creates an intermediate region between internal electrode layer 12 and the dielectric layer, containing both manganese from dielectric layer 11 and copper from internal electrode layer 12. Furthermore, in this intermediate region, manganese from dielectric layer 11 and copper from internal electrode layer 12 can be enriched (concentrated) relative to dielectric layer 11 and internal electrode layer 12, respectively, meaning their concentrations and atomic ratios become higher. Therefore, intermediate region 40 can also include both a concentrated portion (also called a "concentrated portion") of manganese from dielectric layer 11 and a concentrated portion of copper from internal electrode layer 12.

[0121] Furthermore, according to the research of the present inventors, the continuity rate of the internal electrode layer 12 can be particularly improved by having the multilayer ceramic capacitor include the intermediate region.

[0122] Therefore, the internal electrode layer 12 can contain base metals 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 a degree that forms the above-mentioned intermediate region. The details of the intermediate region will be described later.

[0123] In addition to copper, the internal electrode layer 12 may contain other components commonly used in internal electrode layers of multilayer ceramic capacitors. In particular, the internal electrode layer 12 may contain, as a main component, a base metal such as nickel (Ni), tin (Sn), or tungsten (W), or an alloy containing one or more base metals selected from these base metals, i.e., the largest component by mass.

[0124] The internal electrode layer 12 preferably contains nickel because of excellent electrical characteristics and the ability to reduce costs, and may contain nickel as a main component.

[0125] 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 the first internal electrode layer 12a and the main component of the second internal electrode layer 12b may both be nickel.

[0126] (3-2) Continuity of the Internal Electrode Layer

[0127] The continuity ratio of the internal electrode layer 12 is not particularly limited, but is preferably high, preferably 75% or higher, and more preferably 80% or higher, from the perspective of achieving the designed capacitance of the multilayer ceramic capacitor 100. The continuity ratio of the internal electrode layer 12 can be 100% or lower.

[0128] The evaluation method of the continuity rate of the internal electrode layer 12 is described in the examples, and therefore the description thereof is omitted here.

[0129] (3-3) Regarding the thickness of the internal electrode layer

[0130] The thickness of the internal electrode layer 12 is not particularly limited, but is preferably 0.8 μm or less, and more preferably 0.6 μm or less, for example, from the viewpoint of miniaturizing the multilayer ceramic capacitor 100 and increasing the number of layers to increase capacitance.

[0131] The lower limit of the thickness of the internal electrode layer 12 is not particularly limited. From the perspective of improving productivity and yield, for example, when forming by printing a metal conductive paste using a printing method such as screen printing or gravure printing, the thickness can be 0.4 μm or greater. For example, when forming by a thin film process such as sputtering or vapor deposition, the thickness can be 0.1 μm or greater, which is thinner than that achieved by printing methods.

[0132] When evaluating the thickness of the internal electrode layer 12, similarly to the evaluation of the thickness of the dielectric layer 11, the evaluation is performed on a cross section including the first axis along the stacking direction. For example, from the perspective of ease of polishing and measurement, it is preferable to perform the evaluation on either a cross section that also includes a second axis perpendicular to the stacking direction or a cross section that also includes a third axis perpendicular to the stacking direction and also perpendicular to the second axis.

[0133] The multilayer ceramic capacitor 100 is polished so that the cross section described above can be viewed. Five layers are selected from each of the center, top, and bottom ends of the exposed internal electrode layers 12 in the first axial direction. If the number of internal electrode layers 12 is even, six layers are selected from the center. The thickness of each selected internal electrode layer 12 is measured at a total of three locations: the center, left end, and right end. The average of the measured thicknesses is used as the thickness of each internal electrode layer 12. The average of the thicknesses of all selected and evaluated internal electrode layers 12 can be used as the thickness of the internal electrode layers 12 in the multilayer ceramic capacitor 100.

[0134] exist Figure 1 、 Figure 2 In the example shown, the first axis along the stacking direction is the Z-axis. Therefore, the multilayer ceramic capacitor 100 is polished along the Y-axis to expose the XZ plane, where the dielectric layers 11 and internal electrode layers 12 are stacked. In this case, five internal electrode layers 12 are selected from the XZ plane exposed by polishing, located at the center along the Z-axis, which serves as the first axis, and five internal electrode layers 12 are selected from each of the upper and lower ends along the Z-axis, which serves as the first axis. Furthermore, if the number of internal electrode layers 12 is even, six layers may be selected from the center. In this case, the selected internal electrode layers 12 are selected from within the capacitor portion 14.

[0135] Then, for each selected internal electrode layer 12, the thickness is measured at three locations along the X-axis (second axis) at intervals of 1 / 4, 1 / 2, and 3 / 4 of the length of the internal electrode layer 12 along the X-axis from the end, and the average of these measurements is used as the thickness of the internal electrode layer 12. The thickness of all selected internal electrode layers 12 is measured through the same procedure, and the average of the thicknesses of all selected and evaluated internal electrode layers 12 is used as the thickness of the internal electrode layer 12 in the evaluated multilayer ceramic capacitor 100.

[0136] (4) About the middle area

[0137] Figure 4 A partially enlarged view of the dielectric layer 11 and the internal electrode layer 12 in the main body 10 is shown. Figure 4 For example Figure 3 Magnified view of area D.

[0138] The multilayer ceramic capacitor 100 includes an intermediate region 40 disposed between the dielectric layer 11 and the internal electrode layer 12 and containing manganese and copper. Figure 4 The diagram is schematically shown, and the thickness of the intermediate region 40 is constant and shown as a continuous layer, but the present invention is not limited to this form. The intermediate region 40 may be discontinuous or may have a different thickness depending on the position.

[0139] The presence or absence of the intermediate region 40 can be confirmed by elemental mapping using energy dispersive X-ray spectroscopy (EDS) analysis using a transmission electron microscope (TEM) or a scanning transmission electron microscope (Scanning Transmission Electron Microscope). When performing the evaluation, the evaluation is performed using a cross section including a first axis along the stacking direction. For example, considering the ease of polishing and measurement, it is preferred to perform the evaluation on any one of a cross section including a second axis set perpendicular to the stacking direction and a cross section including a third axis set perpendicular to the stacking direction and also perpendicular to the second axis. Figure 1 、 Figure 2 In the example shown, the first axis, which serves as the lamination direction, is the Z-axis. Therefore, the multilayer ceramic capacitor 100 is polished along the Y-axis, the third axis, to expose the XZ plane where the dielectric layers 11 and the internal electrode layers 12 are laminated. This sample, sliced ​​to a thickness of approximately 0.1 μm, is then subjected to TEM / STEM-EDX analysis to confirm the presence of the intermediate region 40.

[0140] For example, by observing the portion where the dielectric layer 11 and the internal electrode layer 12 are stacked in the result of the element mapping, it is possible to determine whether the intermediate region 40 is formed.

[0141] When the above samples were analyzed by TEM / STEM-EDX, Figure 5 As shown in (A), the distribution area of ​​the elements contained in the dielectric contained in the dielectric layer 11 can be confirmed. Figure 5 In (A), a case where the dielectric layer 11 contains barium titanate as a dielectric is taken as an example, and a titanium distribution region 51 is shown.

[0142] In addition, when the above samples were analyzed by TEM / STEM-EDX, Figure 5 As shown in (B), the distribution area of ​​the base metal element contained as the main component of the internal electrode layer 12 can be confirmed. Figure 5 In (B), the case where the internal electrode layer 12 contains nickel as a base metal is taken as an example, and the nickel distribution region 52 is shown.

[0143] In the case where the intermediate region 40 is formed, as shown in FIG. Figure 5As shown in (C), in the element mapping result for copper, the copper distribution region 53 exists so as to exceed the nickel distribution region 52, which is the distribution region of the base metal element contained as the main component in the internal electrode layer 12. In this case, it can be observed that the copper distribution region 53 extends to the titanium distribution region 51, which is the distribution region of the element contained in the dielectric contained in the dielectric layer 11.

[0144] And, as Figure 5 As shown in (D) of FIG. 1 , in the element mapping result regarding manganese, a manganese distribution region 54 exists so as to exceed 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 can be observed that the manganese distribution region 54 extends into 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.

[0145] That is, when element mapping of copper and manganese is performed, if a region where the copper distribution region 53 and the manganese distribution region 54 overlap each other occurs near the boundary between the dielectric layer 11 and the internal electrode layer 12 , it can be determined that the intermediate region 40 is formed.

[0146] Regarding copper, there are cases where uneven distribution of elements can be observed within the copper distribution area 53. For example, Figure 5 As shown in (C), in the copper distribution area 53, in the portion considered to be equivalent to the middle area 40, a thickening portion 531 can be observed where the copper concentration is higher than that in the nickel distribution area 52. Figure 5 In the middle region 40 shown in FIG. 1 (C), the copper concentration may be higher than that in the nickel distribution region 52 considered to correspond to the internal electrode layer 12 .

[0147] Regarding manganese, there are also cases where uneven distribution of the element can be observed in the manganese distribution area 54. For example, Figure 5 As shown in (D), in the manganese distribution region 54, which is considered to be equivalent to the middle region 40, a thickening portion 541 can be observed where the manganese concentration is higher than that in the titanium distribution region 51. Figure 5 In the middle region 40 shown in FIG. 1 (D), the manganese concentration is higher than that in the titanium distribution region 51 considered to correspond to the dielectric layer 11 .

[0148] When copper is not added to internal electrode layer 12 as in the conventional art, concentrated portion 541 having a higher manganese concentration than other portions does not exist in manganese distribution region 54. Manganese and copper together form a region that can be defined as intermediate region 40 for the first time.

[0149] The intermediate region 40 only needs to contain manganese and copper, and the states of manganese and copper in the intermediate region 40 are 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. In addition, in the intermediate region 40, at least one of manganese and copper may exist in an elemental state without forming a compound.

[0150] By including manganese in dielectric layer 11, the sintering temperature of dielectric layer 11 can be lowered, thereby increasing the continuity ratio of internal electrode layer 12. Increasing the continuity ratio of internal electrode layer 12 increases the intersecting area of ​​the internal electrodes, thereby increasing the actual capacitance of multilayer ceramic capacitor 100. Furthermore, increasing the manganese content in dielectric layer 11 further enhances this effect.

[0151] However, according to studies by the present inventors, if the manganese content of dielectric layer 11 is excessively increased, the DC bias characteristics of capacitance (hereinafter simply referred to as “bias characteristics”) of multilayer ceramic capacitor 100 may deteriorate.

[0152] By adding copper to the internal electrode layer 12 and forming a copper-containing intermediate region 40 between the internal electrode layer 12 and the dielectric layer 11, it is possible to prevent the base metal, the main component of the internal electrode layer 12, from diffusing toward the dielectric layer 11. This can significantly improve the continuity of the internal electrode layer 12 and reduce the degradation of bias characteristics. Furthermore, by ensuring that the ratio of manganese and copper in the intermediate region 40 is within a predetermined range, it is possible to significantly improve the continuity of the internal electrode layer 12 and also enhance bias characteristics.

[0153] (About the composition of the middle area)

[0154] The composition of the intermediate region 40 is not particularly limited as long as it contains manganese and copper. In particular, from the perspective of improving the continuity rate and bias characteristics of the internal electrode layer 12, it is preferred that the elements be Figure 5 The distribution is similar to that shown in (A) to (D) of FIG. Specifically, the average ratio of the number of manganese atoms in the intermediate region 40 is preferably greater than that in the center portion in the thickness direction of the dielectric layer 11. Furthermore, the average ratio of the number of copper atoms in the intermediate region 40 is preferably greater than that in the center portion in the thickness direction of the internal electrode layer 12.

[0155] Furthermore, when STEM-EDX analysis is performed, for example, the region where elements contained in the dielectric, such as titanium, are distributed in the dielectric layer 11, excluding the intermediate region 40, can be identified as the region of the dielectric layer 11. Furthermore, the region where base metal elements contained as main components in the internal electrode layer 12, such as nickel, are distributed, excluding the intermediate region 40, can be identified as the region of the internal electrode layer 12.

[0156] The intermediate region 40 may be, for example, a region where the copper distribution region 53 and the manganese distribution region 54 overlap with each other.

[0157] The center portion of the dielectric layer 11 in the thickness direction refers to a position that is spaced from the end portion of the dielectric layer 11 in the thickness direction by 1 / 2 of the thickness of the dielectric layer 11. Furthermore, the center portion of the internal electrode layer 12 in the thickness direction refers to a position that is spaced from the end portion of the internal electrode layer 12 in the thickness direction by 1 / 2 of the thickness of the internal electrode layer 12.

[0158] The average value of the atomic ratio of each element contained in each region refers to the average value of the concentration of each element determined by EDX, and the unit is at %.

[0159] The above aspects are preferably evaluated by three-dimensional atom probe analysis, which can more accurately calculate the atomic number ratio of the content of the element at the measurement position.

[0160] Figure 8 3 shows an example of a case where a three-dimensional atom probe analysis is performed from the dielectric layer 11 to the internal electrode layer 12 along the first axis, ie, the Z axis.

[0161] exist Figure 8 In the graph showing the atomic ratios of the elements at the measurement positions obtained by three-dimensional atom probe analysis, the 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 ratio of oxygen is 5 at %, i.e., as a straight line passing through point 81. This is because the internal electrode layer 12 contains almost no oxygen.

[0162] Furthermore, the second boundary L82, which is the boundary between the dielectric layer 11 and the intermediate region 40, is defined as the position where the atomic ratio of the oxygen content is equal to the atomic ratio of the base metal element as the main component, that is, the straight line passing through the point 82. Figure 8 In the graph, point 82 is a curve of the atomic ratio of the oxygen content of the compound having a perovskite structure contained in the dielectric layer 11 and the element of the base metal contained as the main component in the internal electrode layer 12. Figure 8 The intersection of the curve of the atomic ratio of the nickel content in the case of .

[0163] In this case, the average value of the atomic ratio of the manganese content in the intermediate region 40 is preferably greater than the average value of the atomic ratio of the manganese content in the first reference region 83, which is a region of the dielectric layer 11 spaced from the second boundary by 2 nm to 5 nm. In particular, the average value of the atomic ratio of the manganese content in the intermediate region 40 is preferably 1.5 times or more the average value of the atomic ratio of the manganese content in the first reference region 83.

[0164] In addition, when a three-dimensional atom probe analysis is performed, the average value of the atomic ratio of the copper content in the middle region 40 is preferably 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 spaced from the first boundary L81 by more than 2 nm and less than 5 nm.

[0165] From the perspective of improving the bias characteristics of the multilayer ceramic capacitor 100 , it is preferred that a predetermined relationship exist between the average atomic ratio of the manganese content (Mn) in the intermediate region 40 and the average atomic ratio of the copper content (Cu) in the intermediate region 40 .

[0166] Specifically, for example, it is particularly preferable to satisfy the following formula (1) and formula (2).

[0167] Mn≤0.1574Cu+0.1010······(1)

[0168] Mn≥0.12Cu-0.08······(2)

[0169] The effects of manganese and copper contained in the intermediate region 40 will be described below.

[0170] Regarding the effects of manganese:

[0171] During the manufacture and firing of the multilayer ceramic capacitor 100, the effect of manganese can be utilized to lower the firing temperature, thereby improving the continuity of the internal electrode layer 12. Furthermore, at the end of firing, the excess manganese is discharged (diffused) from the dielectric layer 11 into the intermediate region 40, thereby preventing degradation of the bias characteristics.

[0172] About the effect of copper:

[0173] Copper can prevent base metals, which are the main components of internal electrode layers 12, from diffusing toward dielectric layer 11. Therefore, copper contained in intermediate region 40 can particularly improve the continuity of internal electrode layers 12 and reduce degradation of bias characteristics.

[0174] Regarding manganese and copper, when a three-dimensional atom probe analysis is performed on their combination, the average atomic ratio of the manganese content in the middle region 40 is preferably greater than or equal to 0.15 at % and less than or equal to 0.40 at %, and the average atomic ratio of the copper content is preferably greater than or equal to 0.32 at % and less than or equal to 3.15 at %.

[0175] It is also possible that, when a three-dimensional atom probe analysis is performed, the average value of the atomic ratio of the manganese content in the middle region 40 is more than 1.5 times the average value of the atomic ratio of the manganese content in the region of the dielectric layer 11 that is spaced from the second boundary L82 by more than 2 nm and less than 5 nm, i.e., the first reference region 83, and the average value of the atomic ratio of the copper content in the middle region 40 is, for example, more than 0.5 times and less than 3.0 times the atomic ratio of the copper content in the central portion of the adjacent internal electrode layer 12 in the thickness direction along the first axis, i.e., the Z axis.

[0176] When the atomic ratio of the content of the elements contained in the intermediate region 40 is analyzed and quantified using energy dispersive X-ray (EDX) analysis using a transmission electron microscope (TEM) / scanning transmission electron microscope (STEM), there is a possibility that the atomic ratio of the content of the elements in portions other than the intermediate region 40 included in the sample will also be included, and the analysis accuracy may be reduced. This is because when preparing a sample for TEM / STEM observation, the sample is thinned, but since portions other than the intermediate region 40 are included on the back side of the sample, etc., it is possible that the intermediate region 40 cannot be accurately evaluated. For example, when comparing two regions with obvious large differences, there is no problem even if TEM / STEM-EDX analysis is used, but in order to accurately analyze the content ratio of the elements contained in the intermediate region 40, the concentration obtained by quantification using a three-dimensional atom probe (3DAP) analysis is used.

[0177] The average value of the atomic ratio 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 is omitted here.

[0178] [Method for Manufacturing Multilayer Ceramic Capacitor]

[0179] Next, a method for manufacturing the multilayer ceramic capacitor 100 will be described. Figure 6 Flowchart 60 illustrates a method for manufacturing the multilayer ceramic capacitor 100 . Figure 7 1 and 2 are views illustrating a method for manufacturing the multilayer ceramic capacitor 100 .

[0180] (1) Raw material powder preparation step (S1)

[0181] In the raw material powder preparation step, first, a dielectric material for forming the dielectric layer 11 is prepared. The A-site element and the B-site element contained in the dielectric layer 11 are generally in the form of ABO. 3-α The dielectric layer 11 is contained in the form of a sintered body of particles having a relative dielectric constant (0≤α≤1). For example, barium titanate is a tetragonal compound having a perovskite structure and exhibits a high relative 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 are conventionally known for synthesizing the ceramic main component of the dielectric layer 11, such as a solid phase method, a sol-gel method, and a hydrothermal method. In this embodiment, any of these methods can be employed.

[0182] During the raw material powder preparation step, manganese alone or a manganese-containing compound can be added as an additive to the resulting ceramic raw material powder. Depending on the intended purpose, a predetermined additive compound can be further added to the resulting ceramic raw material powder. Examples of additive compounds 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.

[0183] For example, a ceramic material can be prepared by wet-mixing a manganese-containing additive and a compound containing an additive compound with a ceramic raw material powder, followed by drying and pulverization. For example, the ceramic material obtained as described above can be subjected to pulverization to adjust the particle size as needed, or by combining pulverization with classification to adjust the particle size. Through the above steps, a dielectric material is obtained.

[0184] (2) Coating step (S2)

[0185] Next, in the coating step, a binder such as polyvinyl butyral (PVB) resin, an organic solvent such as ethanol or toluene, and a plasticizer are added to the obtained raw material powder and wet-mixed. In the raw material powder preparation step (S1), a binder may also be added when mixing the ceramic raw material powder and wet-mixed.

[0186] In the coating process, the resulting slurry can be applied to a substrate using, for example, a die coating 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. Ceramic green sheet 71 is an example of a dielectric green sheet.

[0187] (3) Internal electrode layer forming step (S3)

[0188] As described above, the first and second internal electrode layers 12a and 12b can contain base metals such as nickel (Ni), tin (Sn), and tungsten (W), or alloys thereof as main components. The internal electrode layers 12 also contain copper in addition to the above main components.

[0189] 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 components of the first internal electrode layer 12a and the second internal electrode layer 12b may be the same, namely, nickel.

[0190] The metallic conductive paste used to form the precursors of the first and second internal electrode layers 12a and 12b can be prepared by kneading the main component selected as described above, copper, an organic binder, and a solvent. Copper can be added as a single substance or as a compound. Alternatively, it can be an alloy containing a base metal element as the main component and copper, or copper or a copper compound can be added in the form of a coating formed on the surface of a base metal element as the main component or a compound containing the base metal element.

[0191] In the internal electrode layer forming process, as Figure 7 As illustrated in (A), a metal conductive paste for forming an internal electrode layer containing an organic binder can be printed on the surface of the ceramic green sheet 71 by screen printing, gravure printing, etc. As an organic binder, for example, ethyl cellulose (EC), polyvinyl butyral (PVB) resin, etc. can be used. Thus, a first internal electrode layer pattern 72a for the first internal electrode layer 12a or a second internal electrode layer pattern 72b for the second internal electrode layer 12b is arranged on the surface of the ceramic green sheet 71. Various additives such as dispersants and ceramic particles as a common material can also be added to the metal conductive paste. The main component of the ceramic particles is not particularly limited, and is preferably the same as the main component ceramic of the dielectric layer 11. In the case of adding ceramic particles as a common material, it can be added during the mixing of the metal conductive paste. The method for forming the internal electrode layer is not limited to printing, and plating, vacuum evaporation, sputtering, and CVD methods can also be used.

[0192] Alternatively, a dielectric pattern paste for the reverse pattern layer may be obtained by adding a binder such as ethyl cellulose and an organic solvent such as terpineol to the dielectric pattern material obtained in the raw material powder preparation step and kneading the mixture using a roller mill (roller mill). Figure 7 As shown in (A), a dielectric pattern paste may be printed on a ceramic green sheet 71 in a peripheral area where an internal electrode layer pattern is not printed, thereby forming a dielectric pattern 73 and filling the step difference (level difference) 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 stacking unit.

[0193] Afterwards, if Figure 7 As shown in (B), the stacking units can be stacked (stacking process) such that the internal electrode layers and the dielectric layers are interlaced, and the edges of the internal electrode layers are alternately exposed at both end faces in the longitudinal direction of the dielectric layer and alternately extended to a pair of external electrodes. Specifically, a ceramic green sheet 71 printed with a first internal electrode layer pattern 72a and a dielectric pattern 73 and a ceramic green sheet 71 printed with a second internal electrode layer pattern 72b and a dielectric pattern 73 are stacked in this order. For example, the number of stacking units can be 100 to 500.

[0194] (4) Pressing process (S4)

[0195] In the pressure bonding step, a predetermined number of cover sheets, for example, 2 to 10 layers, may be stacked on top and bottom of the laminated body having the stacked lamination units, and then thermally pressure-bonded.

[0196] (5) Singulation process (S5)

[0197] In the singulation step, the pressed-bonded body can be singulated to obtain a singulated laminate. Existing methods such as dicing with a dicing machine or laser cutting can be used as appropriate for the singulation.

[0198] (6) Firing process (S6)

[0199] During the firing step, the individualized laminated bodies can be degreased and fired. The degreasing and firing steps can be performed continuously or separately. The conditions for degreasing and firing are not particularly limited. Degreasing can be performed, for example, in a nitrogen atmosphere at a temperature of 250°C to 500°C.

[0200] Regarding firing, for example, it is possible to -12 ATM and above 10 -8 The sintering is carried out in a reducing atmosphere at a temperature of 1100°C to 1350°C for 5 minutes to 10 hours. The oxygen partial pressure is preferably 10 -12 ATM and above 10-10 The temperature range is preferably from 1150°C to 1350°C. The firing time is preferably from 5 minutes to less than 15 minutes. If necessary, reoxidation treatment may be further performed in a nitrogen atmosphere at from 600°C to 1000°C after firing.

[0201] (7) External electrode forming step (S7)

[0202] In the external electrode forming process, a metal conductive paste for forming the external electrode layer can be formed by screen printing, dipping, etc., and sintered to form it. The metal conductive paste contains base metals such as nickel as the main component, metals such as copper, and an organic binder. The method for forming the external electrode is not limited to printing and dipping, and plating, vacuum evaporation, sputtering, and CVD methods can also be used. In addition, a conductive resin paste can be formed by screen printing, dipping, etc., and the resin is solidified to form it. Copper, nickel, and tin layers can also be formed by plating treatment as needed. In this way, the first external electrode 20a and the second external electrode 20b can be formed. Through the above steps, the stacked ceramic capacitor 100 is completed.

[0203] The above process is merely an example, and the method for manufacturing a multilayer ceramic capacitor according to this embodiment is not limited thereto. For example, a base layer for the external electrodes can be formed by placing it on the surface of a monolithic laminate and firing the base layer simultaneously with the firing of the ceramic. In this case, in the external electrode formation step after firing, a copper, nickel, or tin layer is formed on the base layer by plating, thereby completing the external electrodes.

[0204] [Other embodiments]

[0205] Although the embodiments have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the present invention.

[0206] For example, the above-described 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.

[0207] [Example]

[0208] The following describes the present invention with reference to specific examples, but the present invention is not limited to these examples.

[0209] (1) Evaluation methods

[0210] (1-1) Presence of an intermediate area

[0211] The presence or absence of the intermediate region 40 was confirmed by elemental mapping using energy dispersive X-ray (EDX) analysis using a scanning transmission electron microscope (STEM). Figure 1 、 Figure 2 The first axis along the stacking direction is the Z axis, so Figure 1 、 Figure 2 As shown, the multilayer ceramic capacitor 100 was polished along the third axis, the Y axis, to prepare a sample exposing the XZ plane where the dielectric layer 11 and the internal electrode layer 12 were laminated. This sample was then sliced ​​to a thickness of approximately 0.1 μm and subjected to STEM / EDX analysis to confirm the presence of the intermediate region 40.

[0212] Specifically, in the obtained element mapping results, the portion where the dielectric layer 11 and the internal electrode layer 12 were stacked was observed.

[0213] In the case where the intermediate region 40 is formed, as shown in FIG. Figure 5 As shown in (C), in the element mapping result for copper, the copper distribution region 53 exists so as to exceed the nickel distribution region 52, which is the distribution region of the base metal element contained as the main component in the internal electrode layer 12. In this case, it can be observed that the copper distribution region 53 extends to the titanium distribution region 51, which is the distribution region of the element contained in the dielectric contained in the dielectric layer 11.

[0214] And, as Figure 5 As shown in (D) of FIG. 1 , in the element mapping result regarding manganese, a manganese distribution region 54 exists so as to exceed 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 can be observed that the manganese distribution region 54 extends into 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.

[0215] Specifically, when element mapping of copper and manganese is performed, if a region where the copper distribution region 53 and the manganese distribution region 54 overlap each other occurs near the boundary between the laminated dielectric layer 11 and the internal electrode layer 12 , it is determined that the intermediate region 40 is formed.

[0216] On the other hand, when at least one of the copper distribution region 53 and the manganese distribution region 54 cannot be confirmed or when no region where the copper distribution region 53 and the manganese distribution region 54 overlap each other occurs, it is determined that no intermediate region is formed.

[0217] During the evaluation, the multilayer ceramic capacitor 100 was polished, and from the exposed XZ plane, six internal electrode layers 12 were selected, located at the center along the Z axis (the first axis), and five internal electrode layers 12 were selected, located at the top and bottom ends along the Z axis (the first axis). Furthermore, the aforementioned observations were conducted along the entire periphery of the internal electrode layers 12, near the interfaces between the selected internal electrode layers 12 and the dielectric layer 11. The selected internal electrode layers 12 were selected from within the capacitor portion 14.

[0218] In Table 1, in the column of “Middle Region”, “Yes” indicates if the middle region 40 was confirmed at any location evaluated, and “No” indicates if the middle region was not confirmed at any location evaluated on the sample.

[0219] (1-2) Atomic ratio of manganese and copper in the middle region

[0220] When analyzing the composition of the intermediate region 40, a three-dimensional atom probe (LEAP5000XS, manufactured by AMETEK) was used to analyze the composition along the Z-axis, which serves as the first axis, from the dielectric layer 11 toward the internal electrode layer 12. The three-dimensional atom probe method applies a high voltage to a sample, detects ions evaporated from the sample surface by an electric field using a mass spectrometer, and continuously detects each detected ion in the depth direction. The ions are then arranged in the order of detection to measure the three-dimensional atomic distribution.

[0221] When taking measurements, Figure 1 、 Figure 2 As shown, the multilayer ceramic capacitor 100 was polished along the Y axis to prepare a sample in which the XZ surface on which the dielectric layer 11 and the internal electrode layer 12 were laminated was exposed, and evaluation was performed using the exposed XZ surface.

[0222] Examples of measurement results are Figure 8 As shown. Figure 8 As shown, 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.

[0223] In the measurement results, the first boundary L81 between the internal electrode layer 12 and the intermediate region 40 is defined as a position where the atomic ratio of the oxygen content is 5 at %, that is, a straight line passing through the point 81 .

[0224] Furthermore, the second boundary L82, which serves as the boundary between the dielectric layer 11 and the intermediate region 40, is defined as the position where the atomic ratio of the oxygen content is equal to the atomic ratio of the base metal element as the main component, that is, the straight line passing through point 82. Furthermore, 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 contents of the graph ranging from the first boundary L81 to the second boundary L82 are defined as the data for the intermediate region 40.

[0225] In Comparative Examples 1 to 6, although the intermediate region containing both manganese and copper was not formed, evaluation was performed in the same manner while defining the intermediate region.

[0226] Furthermore, the average atomic ratio of the manganese and copper contents within the intermediate region 40 was determined. During the evaluation, the laminated ceramic capacitor 100 was polished, and from the exposed XZ plane, six dielectric layers were selected from the center along the Z axis, which serves as the first axis, and five dielectric layers were selected from the upper and lower ends along the Z 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 content ratio of manganese and copper relative to all elements detected within the intermediate region 40 was determined. The selected dielectric layer 11 was selected from within the capacitor portion 14.

[0227] The average values ​​of the content ratios of manganese and copper in all the evaluated intermediate regions 40 are shown in the columns “Mn” and “Cu” of “Average value of atomic number ratio of element content in intermediate region” in Table 1, respectively.

[0228] In addition, the average value of the atomic ratio of the manganese content in the first reference region 83, which is a region within the dielectric layer 11 that is 2 nm to 5 nm away from the second boundary L82, is calculated and shown in the column "Atomic ratio of Mn in the first reference region" in Table 1.

[0229] (1-3) Internal Electrode Layer Continuity Rate, Internal Electrode Layer Continuity Rate Judgment

[0230] The continuity rate of the internal electrode layer 12 can be calculated as follows. Figure 1 、 Figure 2 As shown in FIG. 1 , the multilayer ceramic capacitor 100 is polished along the Y axis to prepare a sample in which the XZ plane on which the dielectric layer 11 and the internal electrode layer 12 are laminated is exposed. Next, the exposed XZ plane is used as an observation plane, and a region C included in the observation plane is observed using a SEM (scanning electron microscope) (see FIG. 1 ). Figure 2 ). At this time, if Figure 9As shown, the region that appears bright due to the contrast difference in the SEM image is identified as the electrode portion 91. Furthermore, the length of the electrode portion 91 (in the illustrated example, the length along the X-axis) is measured, and the measured lengths L1, L2, ..., Ln are summed. The value obtained by dividing the sum of the lengths of the electrode portion 91 in region C by the length L0 of the measurement region (length measurement region) (i.e., (L1 + L2 + ... Ln) / L0) can be defined as the continuity ratio of one first internal electrode layer 12a. The main body 10 includes multiple first internal electrode layers 12a, and the continuity ratio may vary depending on which of the multiple first internal electrode layers 12a is considered. Therefore, multiple 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 the multiple different internal electrode layers 12 for evaluation can be the same as those for determining the thickness of the internal electrode layers 12.

[0231] Therefore, during evaluation, the multilayer ceramic capacitor 100 was polished, and from the exposed XZ plane, six internal electrode layers 12 were selected, located at the center along the Z axis (the first axis), and five internal electrode layers 12 were selected, located at the top and bottom ends along the Z axis (the first axis). Furthermore, the selected internal electrode layers 12 were selected from within the capacitor portion 14.

[0232] The internal electrode layer continuity ratio was measured for 10 multilayer ceramic capacitors manufactured under the same conditions for each experimental example. The average of the internal electrode layer continuity ratios for the 10 multilayer ceramic capacitors was used as the internal electrode layer continuity ratio for the multilayer ceramic capacitor in that experimental example.

[0233] Regarding the internal electrode layer continuity ratio, a value of 0 was assigned when the internal electrode layer continuity ratio was 75% or higher, and a value of × was assigned when the internal electrode layer continuity ratio was less than 75%. The evaluation results are shown in the "Internal Electrode Layer Continuity Ratio Determination" column in Table 1.

[0234] (1-4) DC bias characteristics and DC bias characteristics judgment

[0235] The capacitance change rate is calculated using the following formula (3) based on the measured no-load capacitance C0 and the capacitance C3V when DC3V is applied.

[0236] Capacitance change rate = (C3V-C0) / C0×100······(3)

[0237] The DC bias characteristics were measured for 10 multilayer ceramic capacitors manufactured under the same conditions for each experimental example. The average value of the DC bias characteristics of the 10 multilayer ceramic capacitors was used as the DC bias characteristics of the multilayer ceramic capacitor in that experimental example.

[0238] In the column “DC bias characteristics” in Table 1, numerical values ​​normalized with the capacitance change rate in Comparative Example 2 being 100 are shown.

[0239] Regarding the DC bias characteristic judgment, when the measured DC bias characteristic is 100 or greater, it is evaluated as 0; when it is 85 or greater and less than 100, it is evaluated as △; and when it is less than 85, it is evaluated as ×.

[0240] (1-5) Comprehensive judgment

[0241] In the comprehensive judgment, if the internal electrode layer continuity ratio is judged to be 0 and the DC bias characteristic is judged to be 0, the result is 0; if the internal electrode layer continuity ratio is judged to be 0 and the DC bias characteristic is judged to be △, the result is △. In addition, in the comprehensive judgment, if at least one of the internal electrode layer continuity ratio judgment and the DC bias characteristic judgment is x, the result is x.

[0242] (2) Sample preparation conditions

[0243] [Example 1]

[0244] according to Figure 6 According to the flowchart 60 described in FIG. 6 , a multilayer ceramic capacitor was manufactured.

[0245] Specifically, first, barium titanate powder, polyvinyl butyral (PVB) resin, a solvent, a plasticizer, glass powder containing SiO 2 as a sintering aid, and manganese carbonate (MnCO 3 ) are wet-mixed to obtain a slurry (raw material powder preparation step).

[0246] The obtained slurry is applied on a base film, and the slurry applied on the base film is dried to obtain a ceramic green sheet (coating step).

[0247] Next, an organic metal complex solution containing copper is added to Ni powder as the main component metal element and mixed to prepare a mixed powder. Ethyl cellulose (EC), polyvinyl butyral (PVB) resin, etc. as a binder, a solvent and a plasticizer are added to the prepared mixed powder and wet mixed to obtain an internal electrode paste. In addition, as needed, there is no problem even if various auxiliary agents such as dispersants are added in the necessary amount. Then, the internal electrode paste is printed on a part of the surface of the ceramic green sheet to form an internal electrode layer pattern on each ceramic green sheet, thereby forming a stacking unit (internal electrode layer forming process). The stacking unit has a ceramic green sheet and an internal electrode layer pattern formed on the surface of the ceramic green sheet.

[0248] Next, 500 stacking units were stacked to form a stacked body, and the stacked body was pressure-bonded and then individualized to obtain chip-shaped green stacked bodies (pressure-bonding step, individualization step).

[0249] Next, the chip-shaped green laminate was subjected to a degreasing treatment in a nitrogen atmosphere at 500°C.

[0250] After degreasing, the green laminate is coated with a metallic conductive paste containing a nickel-based metal filler, a co-material, a binder, and a solvent, forming the base layer for the external electrodes, from both end faces to each side surface and then dried. The green laminate, coated with the base layer for the external electrodes, is placed in a firing furnace and fired. The firing temperature is 1300°C, and the holding time (i.e., the firing time) is 10 minutes (firing process).

[0251] The first external electrode 20 a and the second external electrode 20 b are formed on the fired laminate by plating (external electrode forming step).

[0252] The resulting multilayer ceramic capacitor had a chip size 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 500 layers. The thicknesses of the dielectric layer 11 and internal electrode layer 12 were evaluated according to the previously described procedure.

[0253] The obtained multilayer ceramic capacitor was evaluated as described above. The evaluation results are shown in Table 1.

[0254] In addition, in Example 1 and Examples 2 to 14 described below, 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, which is a region of the internal electrode layer 12 that is spaced from the first boundary L81 by more than 2 nm and less than 5 nm.

[0255] [Example 2 to Example 14]

[0256] A multilayer ceramic capacitor was produced according to the same procedures as in Example 1, except that the amounts of manganese and copper added to the raw materials for dielectric layer 11 and internal electrode layer 12 were varied so that the average atomic ratio of manganese and copper in the intermediate region reached the values ​​shown in Table 1. Furthermore, the obtained multilayer ceramic capacitor was evaluated as described above. The evaluation results are shown in Table 1.

[0257] [Comparative Example 1]

[0258] Manganese was not added to the raw materials for dielectric layer 11, and the amount of copper added to the raw materials for internal electrode layer 12 was varied so that the average atomic ratio of copper in intermediate region 40 reached the value shown in Table 1. A multilayer ceramic capacitor was manufactured using the same procedures as in Example 1 except for this. The resulting multilayer ceramic capacitor was evaluated as described above. The evaluation results are shown in Table 1.

[0259] [Comparative Examples 2 to 5]

[0260] No copper was added to the internal electrode layer 12. The amount of manganese added to the raw material of the dielectric layer 11 was varied so that the average atomic ratio of manganese in the intermediate region 40 reached the value shown in Table 1. A multilayer ceramic capacitor was manufactured using the same procedures as in Example 1 except for the above. The resulting multilayer ceramic capacitor was evaluated as described above. The evaluation results are shown in Table 1.

[0261] [Comparative Example 6]

[0262] The amounts of manganese and copper added to the raw materials for dielectric layer 11 and internal electrode layer 12 were varied so that the average atomic ratio of manganese and copper in intermediate region 40 reached the values ​​shown in Table 1. The firing time after degreasing was set to 2 hours. A multilayer ceramic capacitor was produced using the same procedures as in Example 1, except for the above. The resulting multilayer ceramic capacitor was evaluated as described above. The evaluation results are shown in Table 1.

[0263] [Table 1]

[0264]

[0265] From the results shown in Table 1, it can be confirmed that in Examples 1 to 14 in which the intermediate region 40 is formed, the internal electrode layer continuity rate is 75% or more, and the continuity rate of the internal electrode layer 12 is high.

[0266] Comparative Examples 2 to 5 show that, as an effect of manganese, the continuity rate of the internal electrode layer 12 increases as the average atomic ratio of manganese content in the intermediate region 40 increases, but the DC bias characteristics deteriorate. As shown in Comparative Example 1, if the intermediate region 40 does not contain manganese, the continuity rate of the internal electrode layer 12 becomes extremely low.

[0267] As shown in Comparative Example 6, when the average 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 rate of the internal electrode layer 12 decreases. This is believed to be because manganese is concentrated in the intermediate region 40 during firing, but the effect of preventing excessive sintering of the internal electrode layer 12 due to manganese is offset by over-firing, such as when the firing time is long.

[0268] In Examples 1 to 8, the average atomic ratio of the manganese content in the middle region 40 and the average atomic ratio of the copper content are particularly the best combination, and the continuity rate and DC bias characteristics of the internal electrode layer 12 are both evaluated as 0, that is, excellent.

[0269] In Examples 9, 11, and 13, although the average atomic ratio of the manganese content was low, the average atomic ratio of the copper content was high. This is thought to be due to excessive diffusion of copper into the dielectric layer 11, which affected the bias characteristics.

[0270] In Examples 10 and 12, the ratio of the average atomic ratio of copper to the average atomic ratio of manganese in the intermediate region 40 is small, so the composite effect of manganese and copper is weakened, which affects the bias characteristics.

[0271] In Example 14, it is considered that the average value of the atomic ratio of the manganese content in the dielectric layer 11 became too large, which affected the bias characteristics.

[0272] When the average atomic ratio of the manganese content in the intermediate region is 0.15 at% to 0.40 at%, the optimal average atomic ratio of the copper content is 0.32 at% to 3.15 at%. This was confirmed because the samples of Examples 1 to 9 also exhibited excellent continuity and bias characteristics.

[0273] The details of this mechanism are not yet clear, but the following hypothesis is considered.

[0274] The coexistence of manganese and copper in the intermediate region is believed to cause manganese to react with copper to form Mn-Cu-O oxide. This is believed to hinder the movement of substances between the intermediate region and the dielectric layer, suppressing the reduction in the manganese concentration in the dielectric layer caused by manganese moving from the dielectric layer to the intermediate region, and suppressing the diffusion of copper into the dielectric layer caused by copper moving from the internal electrode layer through the intermediate region to the dielectric layer. Conversely, if either manganese or copper is excessive (excessive) in the intermediate region, the remaining manganese or copper that has not formed into Mn-Cu-O oxide is likely to migrate to other layers, causing a reduction in the manganese concentration in the dielectric layer and diffusion of copper into the dielectric layer. Therefore, in order to particularly improve the continuity rate and bias characteristics of the internal electrode, it is believed that it is important to contain manganese and copper in the intermediate region at appropriate levels.

[0275] The embodiments of the present invention are as follows, for example.

[0276] <1>

[0277] A laminated ceramic electronic component comprising:

[0278] a plurality of dielectric layers stacked along a first axis;

[0279] a plurality of internal electrode layers respectively disposed between the dielectric layers adjacent to each other along the first axis; and

[0280] arranged in an intermediate region between the dielectric layer and the internal electrode layer,

[0281] The dielectric layer contains a dielectric having the general formula ABO 3-α A compound having a perovskite structure represented by and manganese, wherein 0≤α≤1,

[0282] The internal electrode layer contains base metal elements and copper as main components,

[0283] The intermediate region contains manganese and copper,

[0284] In the case of a three-dimensional atom probe analysis, when a first boundary between the internal electrode layer and the intermediate region is taken as a position where the atomic ratio of the oxygen content is 5 at %, and a second boundary between the dielectric layer and the intermediate region is taken as a position where the atomic ratio of the oxygen content is the same as the atomic ratio of the base metal element as the main component,

[0285] The average atomic ratio of the manganese content in the intermediate region is greater than the average atomic ratio of the manganese content in the first reference region, which is a region of the dielectric layer spaced from the second boundary by 2 nm to 5 nm.

[0286] <2>

[0287] The multilayer ceramic electronic component according to <1>, wherein

[0288] When three-dimensional atom probe analysis is performed, the average value of the atomic ratio of the manganese content in the intermediate region is 1.5 times or more the average value of the atomic ratio of the manganese content in the first reference region.

[0289] <3>

[0290] The multilayer ceramic electronic component according to <1> or <2>, wherein

[0291] When a three-dimensional atom probe analysis is performed, the average value of the atomic ratio of the copper content in the middle region is greater than the average value of the atomic ratio of the copper content in the second reference region, wherein the second reference region is a region of the internal electrode layer that is spaced from the first boundary by more than 2 nm and less than 5 nm.

[0292] <4>

[0293] The multilayer ceramic electronic component according to any one of <1> to <3>, wherein

[0294] According to three-dimensional atom probe analysis, the average atomic ratio of the manganese content in the intermediate region is 0.15 at % to 0.40 at %, and the average atomic ratio of the copper content is 0.32 at % to 3.15 at %.

[0295] <5>

[0296] The multilayer ceramic electronic component according to any one of <1> to <4>, wherein

[0297] The continuity rate of the internal electrode layer is 75% or more.

[0298] <6>

[0299] The multilayer ceramic electronic component according to any one of <1> to <5>, wherein

[0300] The internal electrode layer contains nickel.

[0301] <7>

[0302] The multilayer ceramic electronic component according to any one of <1> to <6>, wherein

[0303] The dielectric layer contains barium titanate as a compound having the perovskite structure.

Claims

1. A multilayer ceramic electronic component, characterized in that: have: a plurality of dielectric layers stacked along a first axis; a plurality of internal electrode layers respectively disposed between the dielectric layers adjacent to each other along the first axis; and arranged in an intermediate region between the dielectric layer and the internal electrode layer, The dielectric layer contains a dielectric having the general formula ABO 3-α A compound having a perovskite structure represented by and manganese, wherein 0≤α≤1, The internal electrode layer contains base metal elements and copper as main components, The intermediate region contains manganese and copper, In the case of a three-dimensional atom probe analysis, when a first boundary between the internal electrode layer and the intermediate region is taken as a position where the atomic ratio of the oxygen content is 5 at %, and a second boundary between the dielectric layer and the intermediate region is taken as a position where the atomic ratio of the oxygen content is the same as the atomic ratio of the base metal element as the main component, The average atomic ratio of the manganese content in the intermediate region is greater than the average atomic ratio of the manganese content in the first reference region, which is a region of the dielectric layer spaced from the second boundary by 2 nm to 5 nm.

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

3. The multilayer ceramic electronic component according to claim 1, wherein: When a three-dimensional atom probe analysis is performed, the average value of the atomic ratio of the copper content in the middle region is greater than the average value of the atomic ratio of the copper content in the second reference region, wherein the second reference region is a region of the internal electrode layer that is spaced from the first boundary by more than 2 nm and less than 5 nm.

4. The multilayer ceramic electronic component according to any one of claims 1 to 3, wherein: According to three-dimensional atom probe analysis, the average atomic ratio of the manganese content in the intermediate region is 0.15 at % to 0.40 at %, and the average atomic ratio of the copper content is 0.32 at % to 3.15 at %.

5. The multilayer ceramic electronic component according to any one of claims 1 to 3, wherein: The continuity rate of the internal electrode layer is 75% or more.

6. The multilayer ceramic electronic component according to any one of claims 1 to 3, wherein: The internal electrode layer contains nickel.

7. The multilayer ceramic electronic component according to any one of claims 1 to 3, wherein: The dielectric layer contains barium titanate as the compound having the perovskite structure.

Images