Multilayer ceramic capacitor and manufacturing method of the same

Abstract

To provide a multilayer ceramic capacitor with excellent reliability in a thin layer, and provide a manufacturing method of the same.SOLUTION: A multilayer ceramic capacitor according to an embodiment, includes: a capacitor body containing a dielectric layer and an internal electrode layer; and an external electrode that is arranged to an outside of the capacitor body. The dielectric layer contains a plurality of dielectric layer crystal particles, and at least one of the dielectric layer crystal particles contains: a core part; and a shell part surrounding at least one part. The shell part contains a barium titanate system main component containing barium (Ba) and titanium (Ti), and a sub-component containing tin (Sn). The shell part contains: a Sn condensation region containing tin (Sn) and a Sn non-condensation region containing tin (Sn) of an atom% that is lower than the Sn condensation region. An atom ratio of tin (Sn) contained in the Sn condensation region against tin (Sn) contained in the Sn non-condensation region is 2.0 or more and 6.0 or less.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a multilayer ceramic capacitor and a method for manufacturing the same.

Background Art

[0002] As electronic components using ceramic materials, there are capacitors, inductors, piezoelectric elements, varistors, thermistors, etc. Among such ceramic electronic components, a multilayer ceramic capacitor (MLCC) can be used in various electronic devices due to its advantages of being small in size, having a high capacitance guaranteed, and being easy to mount.

[0003] For example, a multilayer ceramic capacitor (MLCC) can be used as a chip-shaped capacitor mounted on a substrate of various electronic products such as video equipment such as a liquid crystal display (LCD), a plasma display panel (PDP), an organic light-emitting diode (OLED), a computer, a personal digital assistant, and a smartphone, to play a role of charging or discharging electricity.

Summary of the Invention

Problems to be Solved by the Invention

[0004] In particular, as the demand for ultra-small and high-capacitance MLCCs for IT increases, high reliability is required under an ultra-thin layer design.

[0005] One embodiment provides a multilayer ceramic capacitor having excellent reliability in a thin layer.

[0006] Another embodiment provides a method for manufacturing the multilayer ceramic capacitor.

Means for Solving the Problems

[0007] One embodiment provides a multilayer ceramic capacitor including a capacitor body including a dielectric layer and an internal electrode layer, and an external electrode disposed outside the capacitor body. The dielectric layer includes a plurality of dielectric grains, and at least one of the dielectric grains includes a core portion and a shell portion surrounding at least a part of the core portion. The shell portion has a barium titanate-based main component including barium (Ba) and titanium (Ti), and a sub-component including tin (Sn). The shell portion includes a Sn-concentrated region including tin (Sn), and a Sn-non-concentrated region including tin (Sn) at an atomic percentage lower than that of the Sn-concentrated region. An atomic ratio of the tin (Sn) included in the Sn-concentrated region to the tin (Sn) included in the Sn-non-concentrated region is 2.0 or more and 6.0 or less.

[0008] The shell portion may be a region from the outermost contour of the dielectric grain to a depth of 15 nm or more and 25 nm or less inward.

[0009] During TEM-EDS (transmission electron microscope - energy dispersive spectroscopy) line analysis with respect to a straight line section from one point on the outermost contour of the dielectric grain across the center to another point on the outermost contour, the Sn-concentrated region can exhibit the highest peak of the atomic percentage of tin (Sn).

[0010] The Sn-non-concentrated region can include tin (Sn) at 0.8 atomic percentage or less with respect to the total amount of atoms of all elements included in the shell portion.

[0011] The length of the Sn-concentrated region may be 40% or more and 100% or less of the major axis length of the dielectric grain.

[0012] In the dielectric layer including 30 or more and 50 or less dielectric grains, the Sn-concentrated region may be included at 30% or more and 100% or less of the number of the dielectric grains.

[0013] The average particle size of the dielectric grains may be 80 nm or more and 160 nm or less.

[0014] The core part may contain a barium titanate-based main component containing barium (Ba) and titanium (Ti).

[0015] Tin (Sn) may be contained in the shell part in an amount of 0.01 mol part or more and 5 mol parts or less with respect to 100 mol parts of the barium titanate-based main component.

[0016] The sub-component may further contain dysprosium (Dy), terbium (Tb), manganese (Mn), vanadium (V), barium (Ba), silicon (Si), aluminum (Al), calcium (Ca), or a combination thereof.

[0017] With respect to 100 mol parts of the barium titanate-based main component, the dysprosium (Dy) may be contained in an amount of 0.01 mol part or more and 5 mol parts or less, the terbium (Tb) may be contained in an amount of 0.01 mol part or more and 5 mol parts or less, the manganese (Mn) may be contained in an amount of 0.01 mol part or more and 5 mol parts or less, the vanadium (V) may be contained in an amount of 0.01 mol part or more and 5 mol parts or less, the barium (Ba) may be contained in an amount of 0.01 mol part or more and 5 mol parts or less, the silicon (Si) may be contained in an amount of 0.01 mol part or more and 5 mol parts or less, the aluminum (Al) may be contained in an amount of 0.01 mol part or more and 5 mol parts or less, and the calcium (Ca) may be contained in an amount of 0.01 mol part or more and 5 mol parts or less.

[0018] Another embodiment includes the steps of: manufacturing a dielectric slurry by mixing barium titanate-based main component powder and sub-component powder containing a tin (Sn) compound; manufacturing a dielectric green sheet using the dielectric slurry and forming a conductive paste layer on the surface of the dielectric green sheet; manufacturing a dielectric green sheet laminate by laminating the dielectric green sheets with the conductive paste layer formed thereon; firing the dielectric green sheet laminate to manufacture a capacitor body including a dielectric layer and an internal electrode layer; and forming an external electrode on one surface of the capacitor body. The dielectric layer includes a plurality of dielectric crystal grains, and at least one of the dielectric crystal grains includes a core portion and a shell portion surrounding at least a part of the core portion. The shell portion includes an Sn enrichment region containing tin (Sn) and an Sn non-enrichment region containing tin (Sn) at an atomic percentage lower than that of the Sn enrichment region. The atomic ratio of the tin (Sn) contained in the Sn enrichment region to the tin (Sn) contained in the Sn non-enrichment region is 2.0 or more and 6.0 or less. A method for manufacturing a multilayer ceramic capacitor is provided.

[0019] The tin (Sn) compound can be mixed in an amount of 0.01 mole part or more and 5 mole parts or less with respect to 100 mole parts of the barium titanate-based main component powder.

[0020] The sub-component powder can further include a dysprosium (Dy) compound, a terbium (Tb) compound, a manganese (Mn) compound, a vanadium (V) compound, a barium (Ba) compound, a silicon (Si) compound, an aluminum (Al) compound, a calcium (Ca) compound, or a combination thereof.

[0021] The dysprosium (Dy)-containing compound may be contained in an amount of 0.01 to 5 mole parts, the terbium (Tb)-containing compound may be contained in an amount of 0.01 to 5 mole parts, the manganese (Mn)-containing compound may be contained in an amount of 0.01 to 5 mole parts, the vanadium (V)-containing compound may be contained in an amount of 0.01 to 5 mole parts, the barium (Ba)-containing compound may be contained in an amount of 0.01 to 5 mole parts, the silicon (Si)-containing compound may be contained in an amount of 0.01 to 5 mole parts, the aluminum (Al)-containing compound may be contained in an amount of 0.01 to 5 mole parts, and the calcium (Ca)-containing compound may be contained in an amount of 0.01 to 5 mole parts, based on 100 mole parts of the barium titanate-based main component powder.

Advantages of the Invention

[0022] The multilayer ceramic capacitor according to one embodiment can improve the reliability in a thin layer by suppressing the grain growth of dielectric crystal grains and improving the resistance of grain boundaries.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6a

Figure 6b

Figure 7

Figure 8

Figure 9

Figure 10

Best Mode for Carrying Out the Invention

[0024] Hereinafter, embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement it with reference to the attached drawings. In order to clearly explain the present invention in the drawings, parts unnecessary for the explanation are omitted, and the same reference numerals are given to the same or similar components throughout the specification. Also, in the attached drawings, some components are exaggerated, omitted, or schematically illustrated, and the sizes of the components do not fully reflect the actual sizes.

[0025] The attached drawings are only for facilitating the understanding of the embodiments disclosed in this specification, and the technical idea disclosed in this specification is not limited by the attached drawings, and it should be understood to include all modifications, equivalents, and alternatives included in the idea and technical scope of the present invention.

[0026] Terms including ordinal numbers such as first, second, etc. can be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

[0027] Also, when a part such as a layer, film, region, or plate is "on" or "above" another part, this includes not only the case where it is directly above the other part but also the case where there are other parts in between. Conversely, when a part is "directly above" another part, it means that there are no other parts in between. Also, being "on" or "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "on" or "above" the side opposite to the direction of gravity.

[0028] Throughout the specification, terms such as "comprising" or "having" are intended to specify the presence of the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and it should not be understood as precluding the presence or possibility of addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. Therefore, when a part "comprises" a certain component, this means that it can further include other components rather than excluding other components unless there is a contrary description.

[0029] Also, throughout the specification, when it is said "on a plane", this means when the target part is viewed from above, and when it is said "in a cross-section", this means when the cross-section obtained by vertically cutting the target part is viewed from the side.

[0030] Also, throughout the specification, when it is said "connected", this does not only mean that two or more components are directly connected, but also means that two or more components are indirectly connected through other components, not only physically connected but also electrically connected, or can be meant to be integrated although named differently depending on their positions or functions.

[0031] Hereinafter, a multilayer ceramic capacitor according to an embodiment will be described with reference to FIGS. 1 to 3.

[0032] FIG. 1 is a perspective view showing a multilayer ceramic capacitor according to an embodiment, FIG. 2 is a cross-sectional view of the multilayer ceramic capacitor cut along line I-I' of FIG. 1, and FIG. 3 is a cross-sectional view of the multilayer ceramic capacitor cut along line II-II' of FIG. 1.

[0033] The L-axis, W-axis, and T-axis shown in FIGS. 1 to 3 indicate the length direction, width direction, and thickness direction of the capacitor body 110, respectively. Here, the thickness direction (T-axis direction) may be a direction perpendicular to the wide surface (main surface) of the sheet-shaped component, and as an example, it can be used as the same concept as the stacking direction in which the dielectric layer 111 is stacked. The length direction (L-axis direction) may be a direction that extends parallel to the wide surface (main surface) of the sheet-shaped component and is substantially perpendicular to the thickness direction (T-axis direction), and as an example, it may be a direction in which the first external electrode 131 and the second external electrode 132 are located on both sides. The width direction (W-axis direction) may be a direction that extends parallel to the wide surface (main surface) of the sheet-shaped component and is substantially perpendicular to the thickness direction (T-axis direction) and the length direction (L-axis direction), and the length of the sheet-shaped component in the length direction (L-axis direction) may be even longer than the length in the width direction (W-axis direction).

[0034] Referring to FIGS. 1 to 3, the multilayer ceramic capacitor 100 according to this embodiment includes a capacitor body 110 and external electrodes 131 and 132 disposed outside the capacitor body 110. The external electrodes 131 and 132 may include a first external electrode 131 and a second external electrode 132 disposed at both ends facing each other in the length direction (L-axis direction) of the capacitor body 110.

[0035] The capacitor body 110 may be, for example, a substantially hexahedral shape.

[0036] For the convenience of explaining an embodiment, two surfaces of the capacitor body 110 facing each other in the thickness direction (T-axis direction) are defined as the first surface and the second surface, two surfaces of the capacitor body 110 facing each other in the length direction (L-axis direction) and connected to the first surface and the second surface are defined as the third surface and the fourth surface, and two surfaces of the capacitor body 110 facing each other in the width direction (W-axis direction) and connected to the first surface and the second surface and the third surface and the fourth surface are defined as the fifth surface and the sixth surface.

[0037] As an example, the first surface, which is the lower surface, may be the surface facing the mounting direction. Also, the first surface to the sixth surface may be flat, but an embodiment is not limited thereto. For example, the first surface to the sixth surface may be a curved surface with a convex central portion, and the corners, which are the boundaries of each surface, may have a rounded shape.

[0038] The shape, dimensions, and the number of stacked dielectric layers 111 of the capacitor body 110 are not limited to those shown in the drawings of this embodiment.

[0039] The capacitor body 110 includes a plurality of dielectric layers 111 and internal electrode layers 121, 122. Specifically, the capacitor body 110 includes a plurality of dielectric layers 111 and a first internal electrode 121 and a second internal electrode 122 that are alternately arranged in the thickness direction (T-axis direction) with the dielectric layers 111 interposed therebetween.

[0040] At this time, the boundaries between the respective adjacent dielectric layers 111 of the capacitor body 110 may be integrated to such an extent that they are difficult to confirm without using a scanning electron microscope (SEM).

[0041] The capacitor body 110 can have an active region. The active region is a region where the dielectric layers 111 and the internal electrode layers 121, 122 are alternately arranged with each other, and is a portion that contributes to the formation of the capacitance of the multilayer ceramic capacitor 100. Specifically, the active region may be a region where the first internal electrode 121 or the second internal electrode 122 stacked along the thickness direction (T-axis direction) overlaps.

[0042] Further, the capacitor body 110 may further include a cover portion and a side margin portion.

[0043] The cover portion is a thickness-direction margin portion and can be disposed on the first surface and the second surface sides of the active region in the thickness direction (T-axis direction), respectively. Such a cover portion may be a single dielectric layer 111 or a laminate in which two or more dielectric layers 111 are laminated on the upper surface and the lower surface of the active region, respectively.

[0044] The side margin portion can be regarded as a side cover portion and can be disposed on both opposite end portions of the active region in the width direction (W-axis direction), that is, on the fifth surface and the sixth surface sides, respectively. When applying the conductive paste layer for the internal electrode layer on the surface of the dielectric green sheet, the conductive paste layer is applied only to a partial region of the surface of the dielectric green sheet, and after laminating the dielectric green sheets without applying the conductive paste layer on both side surfaces of the surface of the dielectric green sheet, it can be formed by firing, but it is not limited to such a forming method.

[0045] The cover portion and the side margin portion serve to prevent damage to the first internal electrode 121 and the second internal electrode 122 due to physical or chemical stress.

[0046] The dielectric layer 111 includes a plurality of dielectric crystal grains.

[0047] The dielectric crystal grains according to one embodiment will be described with reference to FIG. 4.

[0048] FIG. 4 is a schematic diagram showing the structure of one dielectric crystal grain in the dielectric layer according to one embodiment.

[0049] Referring to FIG. 4, at least one of the plurality of dielectric crystal grains includes a core portion 10 and a shell portion 20 surrounding at least a part of the core portion 10.

[0050] The core part 10 can contain a barium titanate-based main component including barium (Ba) and titanium (Ti).

[0051] The shell part 20 can contain a barium titanate-based main component including barium (Ba) and titanium (Ti), and a sub-component including tin (Sn).

[0052] The barium titanate-based main component contained in the core part 10 and the shell part 20 is a dielectric base material, has a high dielectric constant, and contributes to the formation of the dielectric constant of the multilayer ceramic capacitor 100.

[0053] The barium titanate-based main component is, for example, BaTiO 3 , Ba(Ti,Zr)O 3 , Ba(Ti,Sn)O 3 , (Ba,Ca)TiO 3 , (Ba,Ca)(Ti,Ca)O 3 , (Ba,Ca)(Ti,Zr)O 3 , (Ba,Ca)(Ti,Sn)O 3 , (Ba,Sr)TiO 3 , (Ba,Sr)(Ti,Zr)O 3 , (Ba,Sr)(Ti,Sn)O 3 , or can include a combination thereof.

[0054] The shell part 20 includes a Sn-concentrated region A and a Sn non-concentrated region B. The Sn-concentrated region A is a region containing tin (Sn) and having a relatively high concentration of tin (Sn). The Sn non-concentrated region B is a region that does not contain tin (Sn) or has a relatively low concentration of tin (Sn).

[0055] Specifically, the shell part 20 can include a Sn-concentrated region A where the concentration of tin (Sn) is high, that is, the atomic % content of tin (Sn) is high, and a Sn non-concentrated region B where the concentration of tin (Sn) is relatively low, that is, the atomic % content of tin (Sn) is lower than that in the Sn-concentrated region A.

[0056] Generally, in order to improve the reliability of a multilayer ceramic capacitor, the size of the dielectric crystal grains should be small and the number of crystal grains per layer of the dielectric layer should be large. However, in a thin layer, since the thickness of the dielectric layer is thin, there may be a case where only about one to two dielectric crystal grains per layer exist due to the grown dielectric crystal grains, which may deteriorate the reliability. According to one embodiment, the grain growth of the dielectric crystal grains can be suppressed by doping tin (Sn) into the barium titanate-based main component. Also, since the bandgap energy of tin (Sn) is larger than that of the barium titanate-based main component, when tin (Sn) is concentrated and a Sn concentration region A exists in the shell portion 20 within the dielectric crystal grains, the grain boundary resistance can be increased.

[0057] In other words, when there exist a Sn concentration region A with a high concentration of tin (Sn) and a Sn non-concentration region B with a relatively low concentration of tin (Sn) in the shell portion 20 within the dielectric crystal grains, the reliability in a thin layer can be improved by suppressing the grain growth of the dielectric crystal grains and increasing the resistance of the grain boundaries.

[0058] Specifically, the atomic ratio of tin (Sn) contained in the Sn concentration region A to tin (Sn) contained in the Sn non-concentration region B may be 2.0 or more and 6.0 or less, for example, 2.1 or more and 5.5 or less, 2.2 or more and 5.0 or less. When having an atomic ratio within the above range, the reliability in a thin layer can be improved by suppressing the grain growth of the dielectric crystal grains and increasing the resistance of the grain boundaries.

[0059] The shell portion 20 may be a region from the outermost contour of the dielectric crystal grain to a depth of 15 nm or more and 25 nm or less, for example, 17 nm or more and 23 nm or less, inward. That is, the thickness t of the shell portion 20 may be 15 nm or more and 25 nm or less, for example, 17 nm or more and 23 nm or less.

[0060] The thickness t of the shell portion 20, the Sn-concentrated region A and the Sn-non-concentrated region B present in the shell portion 20, and the atomic ratio of tin (Sn) between the Sn-concentrated region A and the Sn-non-concentrated region B, which have been described above, can all be confirmed through TEM-EDS (transmission electron microscope - energy dispersive spectroscopy) line analysis.

[0061] TEM-EDS (transmission electron microscope - energy dispersive spectroscopy) line analysis can be performed in the following manner. After placing the multilayer ceramic capacitor 100 in an epoxy mixture and curing it, the W-axis and T-axis direction surfaces (WT surfaces) of the capacitor body 110 are polished to a depth of 1 / 2 in the L-axis direction. After fixing, it is maintained in a vacuum atmosphere chamber, and a cross-sectional sample can be obtained so that the active region where the dielectric layer 111 and the internal electrode layers 121 and 122 intersect can be observed. Next, for the active region of the cross-sectional sample, it can be measured with a transmission electron microscope (TEM) so that at least one layer, for example, 1 to 5 layers of the dielectric layer 111 can be seen. For example, the TEM can be measured under the condition of an acceleration voltage of 200 kV using Xe-FIB (focused ion beam) in a region of about 300 nm × 300 nm within the dielectric layer 111. Then, EDS-line analysis is performed on a straight-line section from one point on the outermost contour of the dielectric crystal grains to the center and across to another point on the outermost contour in the TEM image of the measured cross-sectional sample. Through the EDS-line analysis, the core-shell structure, the atomic ratio of tin (Sn) between the Sn-concentrated region A and the Sn-non-concentrated region B, etc. can be confirmed.

[0062] In the TEM-EDS (transmission electron microscope - energy dispersive spectroscopy) line analysis performed by the aforementioned method, the Sn-concentrated region A may be the section where the peak of the atomic percentage of tin (Sn) appears highest.

[0063] In the Sn enrichment region A, tin (Sn) may be contained in an amount of 0.1 atomic % or more and 3 atomic % or less, for example, 0.5 atomic % or more and 2.8 atomic % or less, based on the total amount of the shell portion 20. Further, in the Sn non-enrichment region B, tin (Sn) may be contained in an amount of 0.8 atomic % or less, for example, 0.01 atomic % or more and 0.8 atomic % or less, or 0.1 atomic % or more and 0.6 atomic % or less, based on the total amount of the shell portion 20. When tin (Sn) in each of the Sn enrichment region A and the Sn non-enrichment region B is contained within the above content range, grain growth of the dielectric crystal grains is suppressed, the resistance of the grain boundaries increases, and high reliability in the thin layer can be ensured.

[0064] The Sn enrichment region A may exist in a form having a predetermined length l and thickness.

[0065] The length l of the Sn enrichment region A may be 40% or more and 100% or less, for example, 50% or more and 100% or less, or 60% or more and 100% or less, of the major axis length of the dielectric crystal grains. When the length of the Sn enrichment region A is within the above range, the resistance characteristics of the grain boundaries can be improved.

[0066] One or more and four or less, for example, two or more and three or less, Sn enrichment regions A may exist within one dielectric crystal grain, specifically, within the shell portion 20 of one dielectric crystal grain.

[0067] Further, on a TEM image in which 30 or more and 50 or less dielectric crystal grains are present within one dielectric layer 111, the Sn enrichment region A may exist in a number corresponding to 30% or more and 100% or less of the number of the dielectric crystal grains. When the Sn enrichment region A exists within the above number range in the dielectric layer 111, not only is the grain growth of the dielectric crystal grains suppressed, but also the resistance of the grain boundaries increases and the reliability in the thin layer can be improved. Here, the TEM image can be measured under the conditions of an acceleration voltage of 200 kV using Xe-FIB in an approximately 1.3 μm × 1.3 μm region where the dielectric layer 111 can be seen.

[0068] The average grain size of the dielectric crystal grains according to an embodiment may be 80 nm or more and 160 nm or less, and for example, may be 90 nm or more and 150 nm or less. When the average grain size of the dielectric crystal grains is within the above range, the grain growth of the dielectric crystal grains is suppressed, and the reliability in the thin layer can be improved.

[0069] The average grain size of the dielectric crystal grains can be obtained by SEM (scanning electron microscope) analysis. Specifically, after putting the multilayer ceramic capacitor into an epoxy mixture and curing it, the W-axis and T-axis direction surfaces (WT surfaces) of the capacitor body are polished to the 1 / 2 point in the L-axis direction. After fixing, it is maintained in a vacuum atmosphere chamber, and a cross-sectional sample can be obtained so that the active part where the dielectric layer and the internal electrode layer intersect can be observed. Next, it can be measured with a scanning electron microscope (SEM) so that at least two layers of the dielectric layer appear in the active part of the cross-sectional sample. For example, the SEM can use the Verios G4 product of Thermo Fisher Scientific and can be measured under the condition of an acceleration voltage of 200 kV using Xe-FIB in a region of about 2.2 μm × 2.2 μm where two dielectric layers can be seen.

[0070] The diameter of the maximum major axis of at least 100 dielectric crystal grains can be measured in the SEM image of the cross-sectional sample, and the average value can be calculated.

[0071] Tin (Sn) may be contained in the shell part 20 in an amount of 0.01 mol part or more and 5 mol parts or less with respect to 100 mol parts of the barium titanate-based main component, and for example, may be contained in an amount of 0.1 mol part or more and 4 mol parts or less. When Sn is contained within the above content range in the shell part 20, the grain growth of the dielectric crystal grains is suppressed, so that the number of dielectric crystal grains per layer of the dielectric layer can increase even in a thin layer, and thus the reliability can be improved.

[0072] The sub-components contained in the shell portion 20 may further include dysprosium (Dy), terbium (Tb), manganese (Mn), vanadium (V), barium (Ba), silicon (Si), aluminum (Al), calcium (Ca), or combinations thereof, in addition to tin (Sn).

[0073] Dysprosium (Dy) may be contained in an amount of 0.01 to 5 mol parts, for example, 0.1 to 4 mol parts, per 100 mol parts of the barium titanate-based main component. Terbium (Tb) may be contained in an amount of 0.01 to 5 mol parts, for example, 0.1 to 4 mol parts, per 100 mol parts of the barium titanate-based main component. Manganese (Mn) may be contained in an amount of 0.01 to 5 mol parts, for example, 0.1 to 4 mol parts, per 100 mol parts of the barium titanate-based main component. Vanadium (V) may be contained in an amount of 0.01 to 5 mol parts, for example, 0.1 to 4 mol parts, per 100 mol parts of the barium titanate-based main component. Barium (Ba) may be contained in an amount of 0.01 to 5 mol parts, for example, 0.1 to 4 mol parts, per 100 mol parts of the barium titanate-based main component. Silicon (Si) may be contained in an amount of 0.01 to 5 mol parts, for example, 0.1 to 4 mol parts, per 100 mol parts of the barium titanate-based main component. Aluminum (Al) may be contained in an amount of 0.01 to 5 mol parts, for example, 0.1 to 4 mol parts, per 100 mol parts of the barium titanate-based main component. Calcium (Ca) may be contained in an amount of 0.01 to 5 mol parts, for example, 0.1 to 4 mol parts, per 100 mol parts of the barium titanate-based main component. When each sub-component is contained within the above content range, the reliability in the thin layer can be improved.

[0074] The average thickness of the dielectric layer 111 may be 0.1 μm or more and 8.0 μm or less, and for example, may be 0.3 μm or more and 3.0 μm or less. When the average thickness of the dielectric layer 111 is within the above range, a highly reliable laminated ceramic capacitor with a thin layer can be ensured.

[0075] The average thickness of the dielectric layer 111 can be measured by ion milling and scanning electron microscope (SEM) analysis after the laminated ceramic capacitor 100 is put into an epoxy mixture and cured and then polished. For example, a Verios G4 product from Thermo Fisher Scientific can be used as the scanning electron microscope, the measurement conditions are 10 kV and 0.2 nA, the analysis magnification may be 100 times, and it can be measured so that at least one layer, three layers, five layers, or ten or more layers of the dielectric layer 111 appear. In the scanning electron microscope (SEM) image, taking the central point in the length direction (L-axis direction) or width direction (W-axis direction) of the dielectric layer 111 as the reference point, it may be the arithmetic mean value of the thickness of the dielectric layer 111 at 10 points separated by a predetermined interval from the reference point. The interval between the 10 points can be adjusted according to the scale of the scanning electron microscope (SEM) image, and for example, the interval may be 1 μm or more and 100 μm or less, 1 μm or more and 50 μm or less, or 1 μm or more and 10 μm or less. At this time, all 10 points must be located within the dielectric layer 111. If all 10 points are not located within the dielectric layer 111, the position of the reference point can be changed or the interval between the 10 points can be adjusted.

[0076] The first internal electrode 121 and the second internal electrode 122 are electrodes having different polarities from each other, and are alternately arranged so as to face each other along the T-axis direction with the dielectric layer 111 interposed therebetween, and one end of each is exposed through the third surface and the fourth surface of the capacitor body 110.

[0077] The first internal electrode 121 and the second internal electrode 122 are electrically insulated from each other by the dielectric layer 111 disposed in the middle.

[0078] The ends of the first internal electrode 121 and the second internal electrode 122 that are alternately exposed through the third and fourth surfaces of the capacitor body 110 are connected to the first external electrode 131 and the second external electrode 132 respectively and electrically connected.

[0079] The first internal electrode 121 and the second internal electrode 122 contain a conductive metal, and can contain, for example, metals such as Ni, Cu, Ag, Pd, Au, or alloys thereof, such as an Ag-Pd alloy.

[0080] Also, the first internal electrode 121 and the second internal electrode 122 can contain dielectric particles of the same composition system as the ceramic material contained in the dielectric layer 111.

[0081] The first internal electrode 121 and the second internal electrode 122 can be formed using a conductive paste containing a conductive metal. As the printing method of the conductive paste, a screen printing method or a gravure printing method can be used.

[0082] The average thickness of the first internal electrode 121 and the second internal electrode 122 may be 0.1 μm or more and 2 μm or less. The average thickness of the first internal electrode 121 and the second internal electrode 122 can be measured by scanning electron microscope (SEM) analysis. Here, since the scanning electron microscope (SEM) analysis is the same as the method when measuring the average thickness of the dielectric layer 111 described above, its description is omitted.

[0083] The capacitor body 110 can be formed by firing a laminate in which a plurality of dielectric layers 111 and internal electrode layers 121, 122 are laminated.

[0084] Voltages of different polarities are provided to the first external electrode 131 and the second external electrode 132, and they are respectively connected to the exposed portions of the first internal electrode 121 and the second internal electrode 122 and electrically connected.

[0085] With the above-described configuration, when a predetermined voltage is applied to the first external electrode 131 and the second external electrode 132, charges are accumulated between the first internal electrode 121 and the second internal electrode 122 facing each other. At this time, the capacitance of the multilayer ceramic capacitor 100 becomes proportional to the area of the overlapping portion of the first internal electrode 121 and the second internal electrode 122 that overlap each other along the T-axis direction in the active region.

[0086] The first external electrode 131 and the second external electrode 132 are respectively disposed on the third surface and the fourth surface of the capacitor body 110, and include a first connection portion and a second connection portion connected to the first internal electrode 121 and the second internal electrode 122, the third surface and the fourth surface of the capacitor body 110, and a first band portion and a second band portion disposed at the corners where the third surface and the fourth surface are in contact with the first surface and the second surface or the fifth surface and the sixth surface.

[0087] The first band portion and the second band portion are respectively extended from the first connection portion and the second connection portion to a part of the first surface and the second surface or the fifth surface and the sixth surface of the capacitor body 110. The first band portion and the second band portion can play a role in improving the fixing strength of the first external electrode 131 and the second external electrode 132.

[0088] The first external electrode 131 and the second external electrode 132 can each include a sintered metal layer in contact with the capacitor body 110, a conductive resin layer disposed to cover the sintered metal layer, and a plating layer disposed to cover the conductive resin layer.

[0089] The sintered metal layer can include a conductive metal and glass.

[0090] The conductive metal can include copper (Cu), nickel (Ni), silver (Ag), palladium (Pd), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), lead (Pb), alloys thereof, or combinations thereof. For example, copper (Cu) can include a copper (Cu) alloy. When the conductive metal contains copper, the metal other than copper may be contained in an amount of 5 mol parts or less with respect to 100 mol parts of copper.

[0091] The glass can include a composition in which oxides are mixed, and may be, for example, one or more selected from the group consisting of silicon oxide, boron oxide, aluminum oxide, transition metal oxide, alkali metal oxide, and alkaline earth metal oxide. The transition metal is selected from the group consisting of zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), and nickel (Ni), the alkali metal is selected from the group consisting of lithium (Li), sodium (Na), and potassium (K), and the alkaline earth metal may be one or more selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).

[0092] Optionally, the conductive resin layer is formed on the sintered metal layer and can be formed, for example, in a form that completely covers the sintered metal layer. On the other hand, the first external electrode 131 and the second external electrode 132 may not include the sintered metal layer, and in this case, the conductive resin layer will be in direct contact with the capacitor body 110.

[0093] The conductive resin layer extends to the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110, and the length of the region (i.e., the band portion) where the conductive resin layer extends and is disposed on the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110 may be longer than the length of the region (i.e., the band portion) where the sintered metal layer extends and is disposed on the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110. That is, the conductive resin layer is formed on the sintered metal layer and can be formed in a form that completely covers the sintered metal layer.

[0094] The conductive resin layer includes a resin and a conductive metal.

[0095] The resin contained in the conductive resin layer has bonding properties and shock absorption properties, and is not particularly limited as long as it can be mixed with the conductive metal powder to form a paste, and can include, for example, a phenol resin, an acrylic resin, a silicon resin, an epoxy resin, or a polyimide resin.

[0096] The conductive metal contained in the conductive resin layer serves to be electrically connected to the first internal electrode 121 and the second internal electrode 122 or the sintered metal layer.

[0097] The conductive metal contained in the conductive resin layer can have a spherical, flake-like, or a combination of these forms. That is, the conductive metal may consist of only flake-like forms, or only spherical forms, or may be a form in which flake-like and spherical forms are mixed.

[0098] Here, the spherical shape can include forms that are not completely spherical. For example, it can include forms in which the length ratio of the major axis to the minor axis (major axis / minor axis) is 1.45 or less. The flake-like powder means a powder having a flat and elongated form, and is not particularly limited. For example, the length ratio of the major axis to the minor axis (major axis / minor axis) may be 1.95 or more.

[0099] The first external electrode 131 and the second external electrode 132 can further include a plating layer disposed outside the conductive resin layer.

[0100] The plating layer can include nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), or lead (Pb) alone or an alloy thereof. For example, the plating layer may be a nickel (Ni) plating layer or a tin (Sn) plating layer, or may be a form in which a nickel (Ni) plating layer and a tin (Sn) plating layer are sequentially laminated, or may be a form in which a tin (Sn) plating layer, a nickel (Ni) plating layer, and a tin (Sn) plating layer are sequentially laminated. Also, the plating layer can include a plurality of nickel (Ni) plating layers and / or a plurality of tin (Sn) plating layers.

[0101] The plating layer can improve the mountability with the substrate of the multilayer capacitor 100, the structural reliability, the durability against the outside, the heat resistance, and the equivalent series resistance (ESR).

[0102] Hereinafter, a method for manufacturing a multilayer ceramic capacitor 100 according to an embodiment will be described.

[0103] The multilayer ceramic capacitor 100 according to an embodiment can be manufactured through the steps of: manufacturing a dielectric slurry by mixing a barium titanate-based main component powder and a sub-component powder containing a tin (Sn) - containing compound; manufacturing a dielectric green sheet using the dielectric slurry and forming a conductive paste layer on the surface of the dielectric green sheet; laminating the dielectric green sheets with the conductive paste layer formed thereon to manufacture a dielectric green sheet laminate; firing the dielectric green sheet laminate to manufacture a capacitor body including a dielectric layer and an internal electrode layer; and forming an external electrode on one surface of the capacitor body.

[0104] First, a dielectric slurry is manufactured by mixing a barium titanate-based main component powder and a sub-component powder containing a tin (Sn) - containing compound.

[0105] The barium titanate-based main component powder can be manufactured by mixing a titanium (Ti) precursor and a barium (Ba) precursor.

[0106] The titanium (Ti) precursor may be an oxide of titanium, a salt, an alkoxide, etc. For example, it can include titanium dioxide, titanium diisopropoxide diacetylacetonate (TPA), titanium alkoxide, or a combination thereof.

[0107] The barium (Ba) precursor is BaO 2 、BaTiO 3 、BaCO 3 、BaO, or a combination thereof.

[0108] The barium (Ba) precursor may be contained in an amount of 0.9 mol or more and 1.1 mol or less with respect to 1 mol of the titanium (Ti) precursor.

[0109] The Sn-containing compound, which is a sub-component powder, may be an oxide, a nitride, or a salt compound, or it can also be used in the form of a sol dispersed in an organic solvent.

[0110] The Sn-containing compound may be mixed in an amount of 0.01 to 5 mole parts, for example, 0.1 to 3 mole parts, per 100 mole parts of the barium titanate-based main component powder. When the Sn-containing compound is mixed within the above content range, the reliability in a thin layer can be improved by suppressing the grain growth of the dielectric crystal grains.

[0111] The sub-component powder may further contain a dysprosium (Dy)-containing compound, a terbium (Tb)-containing compound, a manganese (Mn)-containing compound, a vanadium (V)-containing compound, a barium (Ba)-containing compound, a silicon (Si)-containing compound, an aluminum (Al)-containing compound, a calcium (Ca)-containing compound, or a combination thereof.

[0112] The dysprosium (Dy) - containing compound may be contained in an amount of 0.01 to 5 mole parts, for example, 0.1 to 4 mole parts, per 100 mole parts of the barium titanate - based main - component powder. The terbium (Tb) - containing compound may be contained in an amount of 0.01 to 5 mole parts, for example, 0.1 to 4 mole parts, per 100 mole parts of the barium titanate - based main - component powder. Manganese (Mn) may be contained in an amount of 0.01 to 5 mole parts, for example, 0.1 to 4 mole parts, per 100 mole parts of the barium titanate - based main - component powder. Vanadium (V) may be contained in an amount of 0.01 to 5 mole parts, for example, 0.1 to 4 mole parts, per 100 mole parts of the barium titanate - based main - component powder. Barium (Ba) may be contained in an amount of 0.01 to 5 mole parts, for example, 0.1 to 4 mole parts, per 100 mole parts of the barium titanate - based main - component powder. Silicon (Si) may be contained in an amount of 0.01 to 5 mole parts, for example, 0.1 to 4 mole parts, per 100 mole parts of the barium titanate - based main - component powder. Aluminum (Al) may be contained in an amount of 0.01 to 5 mole parts, for example, 0.1 to 4 mole parts, per 100 mole parts of the barium titanate - based main - component powder. Calcium (Ca) may be contained in an amount of 0.01 to 5 mole parts, for example, 0.1 to 4 mole parts, per 100 mole parts of the barium titanate - based main - component powder. When each of the sub - component powders is contained within the above content range, the reliability in a thin - layer can be improved.

[0113] The dielectric slurry can be produced by additionally mixing additives such as a dispersant, a binder, a plasticizer, a lubricant, an antistatic agent, etc. and a solvent.

[0114] The dispersant can include, for example, a phosphate ester-based dispersant, a polycarboxylic acid-based dispersant, or a combination thereof. The dispersant may be mixed in an amount of 0.1 part by weight or more and 5 parts by weight or less, for example, 0.3 part by weight or more and 3 parts by weight or less, based on 100 parts by weight of the barium titanate-based main component powder. When the dispersant is mixed within the above content range, the dispersibility of the dielectric slurry is excellent, and the amount of impurities contained in the produced dielectric layer can be reduced.

[0115] The binder may be, for example, an acrylic resin, a polyvinyl butyl resin, a polyvinyl acetal resin, an ethyl cellulose resin, etc. The binder may be added in an amount of 0.1 part by weight or more and 50 parts by weight or less, for example, 3 parts by weight or more and 30 parts by weight or less, based on 100 parts by weight of the barium titanate-based main component powder. When the binder is mixed within the above content range, the dispersibility of the dielectric slurry is excellent, and the amount of impurities contained in the produced dielectric layer can be reduced.

[0116] The plasticizer may be, for example, phthalic acid-based compounds such as dioctyl phthalate, benzyl butyl phthalate, dibutyl phthalate, dihexyl phthalate, bis(2-ethylhexyl) phthalate, bis(2-ethylbutyl) phthalate; adipic acid-based compounds such as dihexyl adipate, bis(2-ethylhexyl) adipate; glycol-based compounds such as ethylene glycol, diethylene glycol, triethylene glycol; glycol ester-based compounds such as triethylene glycol dibutyrate, triethylene glycol bis(2-ethylbutyrate), triethylene glycol bis(2-ethylhexanoate), etc. The plasticizer may be added in an amount of 0.1 part by weight or more and 20 parts by weight or less, for example, 1 part by weight or more and 10 parts by weight or less, based on 100 parts by weight of the barium titanate-based main component powder. When the plasticizer is mixed within the above content range, the dispersibility of the dielectric slurry is excellent, and the amount of impurities contained in the produced dielectric layer can be reduced.

[0117] The solvent may be an aqueous solvent such as water; an alcohol solvent such as ethanol, methanol, benzyl alcohol, methoxyethanol; a glycol solvent such as ethylene glycol, diethylene glycol; a ketone solvent such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone; an ester solvent such as butyl acetate, ethyl acetate, carbitol acetate, butyl carbitol acetate; an ether solvent such as methyl cellosolve, ethyl cellosolve, butyl ether, tetrahydrofuran; an aromatic solvent such as benzene, toluene, xylene, etc. The solvent can use an alcohol solvent or an aromatic solvent, for example, considering the solubility and dispersibility of various additives contained in the dielectric slurry. The solvent may be mixed in an amount of 50 parts by weight or more and 1000 parts by weight or less, or for example, 100 parts by weight or more and 500 parts by weight or less, based on 100 parts by weight of the barium titanate-based main component powder. When the solvent is mixed within the above content range, the dielectric slurry components are sufficiently mixed, and thereafter, the removal of the solvent is also easy.

[0118] The mixing of the barium titanate-based main component powder and the sub-component powder can use a wet ball mill or a stirring mill. When using zirconia balls in a wet ball mill, a large number of zirconia balls with a diameter of 0.1 mm or more and 10 mm or less can be used for wet mixing for 8 hours or more and 48 hours or less, or 10 hours or more and 24 hours or less.

[0119] The produced dielectric slurry is formed as a dielectric layer after firing.

[0120] As a method for forming the produced dielectric slurry into a sheet shape, a tape forming method such as a doctor blade method or a calendar roll method can be used. For example, an on-roll coater using a head discharge method can be used, and then a dielectric green sheet can be obtained by drying the formed body.

[0121] In order to form a conductive paste layer that becomes an internal electrode layer after firing, a conductive paste can be produced by mixing conductive powder made of a conductive metal or its alloy, a binder, and a solvent. Further, barium titanate powder may be mixed as a co-material if necessary. The co-material can play a role in suppressing the sintering of the conductive powder during the firing process. A conductive paste layer is formed by applying the conductive paste in a predetermined pattern by various printing methods such as screen printing or transfer methods on the surface of the dielectric green sheet.

[0122] The conductive powder can include nickel (Ni) or a nickel (Ni) alloy.

[0123] Next, a dielectric green sheet laminate is manufactured by laminating a plurality of dielectric green sheets with internal electrode patterns formed thereon and then pressing in the lamination direction. At this time, the dielectric green sheet and the internal electrode pattern can be laminated so that the dielectric green sheet is located on the upper and lower surfaces of the dielectric green sheet laminate in the lamination direction.

[0124] The step of selectively cutting the manufactured dielectric green sheet laminate into a predetermined size by dicing or the like can be performed.

[0125] In addition, the dielectric green sheet laminate can be solidified and dried to remove a plasticizer or the like if necessary, and can be barrel polished using a horizontal centrifugal barrel polishing machine or the like after solidification and drying. In barrel polishing, the dielectric green sheet laminate is put into a barrel container together with media and a polishing liquid, and by applying rotational motion, vibration, etc. to the barrel container, unnecessary parts such as burrs generated during cutting can be polished. Further, after barrel polishing, the dielectric green sheet laminate can be washed with a cleaning liquid such as water and dried.

[0126] Next, the dielectric green sheet laminate can be debound and fired to manufacture a capacitor body.

[0127] The debinding treatment conditions can be appropriately adjusted according to the components of the dielectric layer and the internal electrode layer. For example, the heating rate during debinding treatment may be 5°C / hour or more and 300°C / hour or less, the support temperature may be 180°C or more and 400°C or less, and the temperature holding time may be 0.5 hour or more and 24 hours or less. During the debinding treatment, the atmosphere may be air or a reducing atmosphere.

[0128] The firing treatment conditions can be appropriately adjusted according to the main component composition of the dielectric layer and the main component composition of the internal electrode. For example, firing can be performed at a temperature of 1100°C or more and 1400°C or less, and for example, at a temperature of 1150°C or more and 1300°C or less. Also, firing can be performed for 0.5 hour or more and 8 hours or less, for example, 1 hour or more and 3 hours or less. Further, firing can be performed in a reducing atmosphere, for example, an atmosphere in which a mixed gas of nitrogen and hydrogen is humidified. When the internal electrode contains nickel (Ni) or a nickel (Ni) alloy, the oxygen partial pressure in the firing atmosphere is 1.0×10 -14 MPa or more and 1.0×10 -10 MPa or less.

[0129] After the firing treatment, annealing can be performed if necessary. Annealing is a treatment for re-oxidizing the dielectric layer, and when the firing treatment is performed in a reducing atmosphere, annealing can be performed. The annealing treatment conditions can also be appropriately adjusted according to the components of the dielectric layer. For example, the temperature during annealing may be 950°C or more and 1150°C or less, the time may be 0 hour or more and 20 hours or less, and the heating rate may be 50°C / hour or more and 500°C / hour or less. The annealing atmosphere may be a humidified nitrogen gas (N 2 ) atmosphere, and the oxygen partial pressure may be 1.0×10 -9 MPa or more and 1.0×10 -5 MPa or less.

[0130] For humidifying nitrogen gas, mixed gas, etc. in a debinding process, firing process, or annealing process, for example, a wetter can be used. In this case, the water temperature may be 5°C or higher and 75°C or lower. The debinding process, firing process, and annealing process can be performed continuously or independently.

[0131] Optionally, surface treatments such as sandblasting, laser irradiation, and barrel polishing can be performed on the third and fourth surfaces of the manufactured capacitor body 110. By performing such surface treatments, the ends of the first internal electrode and the second internal electrode are exposed on the outermost surfaces of the third and fourth surfaces, thereby improving the electrical connection between the first external electrode and the second external electrode and the first internal electrode and the second internal electrode, and making it easier to form an alloy part.

[0132] Next, an external electrode is formed on one surface of the manufactured capacitor body 110.

[0133] As an example, after applying a paste for forming a sintered metal layer as the external electrode, it can be sintered to form a sintered metal layer.

[0134] The paste for forming a sintered metal layer can contain a conductive metal and glass. Since the description of the conductive metal and glass is the same as that described above, repeated descriptions are omitted. Further, the paste for forming a sintered metal layer can optionally contain a binder, a solvent, a dispersant, a plasticizer, an oxide powder, etc. As the binder, for example, ethyl cellulose, acrylic, butyral, etc. can be used, and as the solvent, for example, organic solvents such as terpineol, butyl carbitol, alcohol, methyl ethyl ketone, acetone, toluene, or an aqueous solvent can be used.

[0135] As a method of applying the paste for forming the sintered metal layer to the outer surface of the capacitor body 110, dipping method, various printing methods such as screen printing, coating method using a dispenser or the like, spraying method using a spray, etc. can be used. The paste for forming the sintered metal layer is applied to at least the third surface and the fourth surface of the capacitor body 110, and can also be applied to a part of the first surface, the second surface, the fifth surface, or the sixth surface where the band portions of the first external electrode and the second external electrode are selectively formed.

[0136] Thereafter, the capacitor body 110 coated with the paste for forming the sintered metal layer is dried and sintered at a temperature of 700°C or higher and 1000°C or lower for 0.1 hour or more and 3 hours or less to form a sintered metal layer.

[0137] Optionally, a conductive resin layer can be formed by applying a paste for forming a conductive resin layer to the outer surface of the obtained capacitor body 110 and then curing it.

[0138] The paste for forming the conductive resin layer can contain a resin and, optionally, a conductive metal or a non-conductive filler. Since the descriptions regarding the conductive metal and the resin are the same as those described above, repeated descriptions are omitted. Further, the paste for forming the conductive resin layer can optionally contain a binder, a solvent, a dispersant, a plasticizer, an oxide powder, etc. As the binder, for example, ethyl cellulose, acrylic, butyral, etc. can be used, and as the solvent, organic solvents such as terpineol, butyl carbitol, alcohol, methyl ethyl ketone, acetone, toluene, or an aqueous solvent can be used.

[0139] As an example, the method of forming the conductive resin layer can be to dip the capacitor body 110 into the paste for forming the conductive resin layer and then cure it, or print the paste for forming the conductive resin layer on the surface of the capacitor body 110 by a screen printing method or a gravure printing method, or apply the paste for forming the conductive resin layer to the surface of the capacitor body 110 and then cure it to form.

[0140] Next, a plating layer is formed on the outside of the conductive resin layer.

[0141] As an example, the plating layer can be formed by a plating method, and can also be formed by sputtering or electroplating.

[0142] Hereinafter, the above-described embodiments will be described in more detail through examples. However, the following examples are for illustrative purposes only and do not limit the scope of the rights.

[0143] [Examples] (Manufacture of multilayer ceramic capacitor) Examples 1 to 3 and Comparative Examples 1 to 5 Barium titanate (BaTiO 3 ) main component powder, and tin oxide (SnO 2 ) and dysprosium oxide (Dy 2 O 3 ) were mixed to produce a dielectric slurry. At this time, tin oxide (SnO 2 ) and dysprosium oxide (Dy 2 O 3 ) were mixed at 1.5 mol parts each with respect to 100 mol parts of the barium titanate (BaTiO 3 ) main component powder. The mixing was carried out by mechanically milling after adding ethanol / toluene together with a zirconium ball (ZrO- 2 ball) as a dispersion medium, a wetting dispersant, and polyvinyl butyral (PVB) resin as a binder.

[0144] The produced dielectric slurry was used to produce a dielectric green sheet using an on-roll coater of the head discharge method.

[0145] A conductive paste layer containing nickel (Ni) was printed on the surface of a dielectric green sheet, and a dielectric green sheet (width × length × height = 3.2 mm × 2.5 mm × 2.5 mm) with the conductive paste layer formed thereon was laminated and pressure-bonded to produce a dielectric green sheet laminate.

[0146] The dielectric green sheet laminate was subjected to a plasticizing process in a nitrogen atmosphere at 400 °C or lower and then fired at a firing temperature of 1300 °C or lower and a hydrogen concentration of 1.0% H 2 under the following conditions. Specifically, in the case of Comparative Examples 1 to 3, firing was performed at a temperature of 1140 °C or higher and 1160 °C or lower, in the case of Examples 1 to 3, firing was performed at a temperature exceeding 1160 °C and 1220 °C or lower, and in the case of Comparative Examples 4 and 5, firing was performed at a temperature exceeding 1220 °C and 1240 °C or lower, respectively.

[0147] Next, a multilayer ceramic capacitor was manufactured through processes such as external electrode formation and plating.

[0148] Evaluation 1: TEM analysis TEM (transmission electron microscope) analysis was performed on the multilayer ceramic capacitor manufactured in Example 1, and the results are shown in Fig. 5.

[0149] Specifically, after the multilayer ceramic capacitor 100 manufactured in Example 1 was placed in an epoxy mixture and cured, the W-axis and T-axis plane (WT plane) of the capacitor body 110 was polished to a depth of 1 / 2 in the L-axis direction, fixed, and maintained in a vacuum atmosphere chamber to obtain a cross-sectional sample so that the active region where the dielectric layer 111 and the internal electrode layers 121 and 122 intersect could be observed. Next, the active region of the cross-sectional sample was measured with a transmission electron microscope (TEM) so that at least one layer of the dielectric layer 111 could be seen. The TEM was measured under the conditions of an acceleration voltage of 200 kV using Xe-FIB in a region of about 1.3 μm × 1.3 μm where the dielectric layer 111 could be seen.

[0150] Fig. 5 is a TEM image of the dielectric layer according to Example 1.

[0151] Referring to Fig. 5, it can be confirmed that the dielectric layer according to Example 1 contains a plurality of dielectric crystallites, and at least one of them has a Sn concentration region with a high Sn concentration in the shell portion of the core-shell structure.

[0152] Evaluation 2: TEM-EDS line analysis TEM-EDS (transmission electron microscope - energy dispersive spectroscopy) line analysis was performed on the multilayer ceramic capacitors manufactured in Examples 1 to 3 and Comparative Examples 1 to 5, and the results are shown in Figs. 6a and 6b and Table 1 below.

[0153] Specifically, cross-sectional samples were obtained in the same manner as in Evaluation 1 using the multilayer ceramic capacitors manufactured in Examples 1 to 3 and Comparative Examples 1 to 5. Next, the dielectric layer 111 was measured with a transmission electron microscope (TEM) so that at least one layer could be seen in the active region of the cross-sectional sample. The TEM was measured under the conditions of an acceleration voltage of 200 kV using Xe-FIB in a region of about 300 nm × 300 nm in the dielectric layer 111. Next, in the TEM image of the measured cross-sectional sample, as shown in Fig. 6a, EDS-line analysis was performed on a straight-line section from one point on the outermost contour of the dielectric crystallite to the center and then to another point on the outermost contour.

[0154] Fig. 6a is a TEM image showing dielectric crystallites in the dielectric layer according to Example 1, and Fig. 6b is an EDS-line analysis graph for the dielectric crystallites in Fig. 6a.

[0155] Referring to Figs. 6a and 6b, in the case of Example 1, it can be confirmed that one dielectric crystallite has a core portion and a shell portion, and the shell portion is a region from the outermost contour of the dielectric crystallite to a depth of about 20 nm inward. Further, it can be confirmed that the shell portion contains a Sn concentration region, which is a section where the peak of the atomic percentage of tin (Sn) appears highest in the EDS-line analysis graph, and also contains a Sn non-concentration region, which is a section containing tin (Sn) with an atomic percentage lower than that in the Sn concentration region.

[0156] Through the above TEM-EDS line analysis, the atomic % content ratio, i.e., the atomic ratio, of tin (Sn) contained in the Sn-enriched region A and tin (Sn) contained in the Sn non-enriched region B was determined and shown in Table 1 below.

[0157] In Table 1 below, the length of the Sn-enriched region A is a percentage value with respect to the major axis length of the dielectric crystal grains.

[0158]

Table 1

[0159] Evaluation 3: SEM Analysis SEM (scanning electron microscope) analysis was performed on the multilayer ceramic capacitors manufactured in Example 1 and Comparative Example 1, and the average particle size of the dielectric crystal grains was measured, and the results are shown in FIGS. 7 and 8.

[0160] Specifically, after the multilayer ceramic capacitors manufactured in Example 1 and Comparative Example 1 were put into an epoxy mixture and cured, the W-axis and T-axis direction surfaces (WT surfaces) of the capacitor body were polished to the 1 / 2 point in the L-axis direction, fixed, and maintained in a vacuum atmosphere chamber to obtain a cross-sectional sample so that the active part where the dielectric layer and the internal electrode layer intersect could be observed. Next, measurement was performed with a scanning electron microscope (SEM) such that at least two layers of the dielectric layer appeared in the active part of the cross-sectional sample. The SEM used was a Verios G4 product of Thermo Fisher Scientific, and measurement was performed under the condition of an acceleration voltage of 200 kV using Xe-FIB in a region of about 2.2 μm × 2.2 μm where two dielectric layers could be seen. The average particle size of the dielectric crystal grains was determined by measuring the diameters of the major axes of at least 100 dielectric crystal grains in the SEM image of the cross-sectional sample and calculating the average value.

[0161] FIG. 7 is an SEM image of the dielectric layer according to Example 1, and FIG. 8 is an SEM image of the dielectric layer according to Comparative Example 1.

[0162] Referring to FIGS. 7 and 8, in the case of Example 1 which includes a Sn-concentrated region and a Sn-non-concentrated region within the shell portion of the dielectric crystal grains and the atomic ratio of tin (Sn) in the Sn-concentrated region to the Sn-non-concentrated region is in the range of 2.0 or more and 6.0 or less, the average grain size of the dielectric crystal grains is 120 nm, while the average grain size of the dielectric crystal grains according to Comparative Example 1 is 170 nm. From this, it can be seen that the grain growth of the dielectric crystal grains according to one embodiment is suppressed and the reliability in the thin layer is improved.

[0163] Evaluation 4: Reliability Accelerated life evaluations were performed on the multilayer ceramic capacitors manufactured in Examples 1 to 3 and Comparative Examples 1 to 5, and the results are shown in Table 2 below, FIGS. 9 and 10.

[0164] Specifically, after mounting 40 sample chips on a reliability substrate, the failure rate (fail%) at which a failure of the chip occurs within 10 hours was determined under the conditions of a temperature of 125° C. and a voltage of 6V. Also, when the failure rate was 5% or less, it was determined as ○, when the failure rate was more than 5% and 20% or less, it was determined as Δ, and when the failure rate was more than 20%, it was determined as X.

[0165]

Table 2

[0166] FIG. 9 is a graph evaluating the accelerated life of the multilayer ceramic capacitor according to Example 1, and FIG. 10 is a graph evaluating the accelerated life of the multilayer ceramic capacitor according to Comparative Example 1.

[0167] Referring to Table 2, FIGS. 9 and 10, in the case of Example 1 which includes a Sn-concentrated region and a Sn-non-concentrated region within the shell portion of the dielectric crystal grains and the atomic ratio of tin (Sn) in the Sn-concentrated region to the Sn-non-concentrated region is in the range of 2.0 or more and 6.0 or less, it can be seen that the accelerated life characteristics are superior to those of Comparative Example 1. Therefore, it can be confirmed that the multilayer ceramic capacitor according to one embodiment has excellent reliability in the thin layer.

[0168] Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made and implemented within the scope of the claims, the description of the invention, and the accompanying drawings, and it is natural that these also belong to the scope of the present invention.

Explanation of Reference Numerals

[0169] 100: Multilayer ceramic capacitor 110: Capacitor body 111: Dielectric layer 121: First internal electrode 122: Second internal electrode 131: First external electrode 132: Second external electrode 10: Core 20: Shell A: Sn-enriched region B: Sn-non-enriched region t: Thickness of the shell portion 20 l: Length of the Sn-enriched region A

Claims

1. a capacitor body including a dielectric layer and an internal electrode layer; and an external electrode disposed outside the capacitor body; the dielectric layer includes a plurality of dielectric crystal grains; At least one of the dielectric crystal grains includes a core portion and a shell portion surrounding at least a portion of the core portion, The shell portion includes a barium titanate-based main component including barium (Ba) and titanium (Ti) and a subcomponent including tin (Sn), The shell portion includes an Sn-enriched region containing tin (Sn) and an Sn-non-enriched region containing tin (Sn) at a lower atomic percent than the Sn-enriched region, The atomic ratio of tin (Sn) contained in the Sn-enriched region to tin (Sn) contained in the Sn-non-enriched region is 2.0 or more and 6.0 or less.

2. The multilayer ceramic capacitor according to claim 1 , wherein the shell portion is a region extending from an outermost portion of the dielectric crystal grain to a depth of 15 nm to 25 nm inside the dielectric crystal grain.

3. 2. The multilayer ceramic capacitor according to claim 1, wherein, in a line analysis using a transmission electron microscope-energy dispersive spectroscopy (TEM-EDS) for a straight line section from one point on the outermost periphery of the dielectric crystal grain across the center to another point on the outermost periphery, the Sn-enriched region has the highest peak of tin (Sn) atomic percentage.

4. 2 . The multilayer ceramic capacitor according to claim 1 , wherein the Sn non-concentrated region contains tin (Sn) in an amount of 0.8 atomic % or less with respect to a total amount of atoms of all elements contained in the shell portion.

5. 2. The multilayer ceramic capacitor according to claim 1, wherein the length of the Sn-enriched region is 40% or more and 100% or less of the major axis length of the dielectric crystal grain.

6. 2. The multilayer ceramic capacitor according to claim 1, wherein the Sn-enriched region is included in a dielectric layer including 30 to 50 dielectric crystal grains, the Sn-enriched region occupying 30% to 100% of the number of the dielectric crystal grains.

7. 2. The multilayer ceramic capacitor according to claim 1, wherein the average grain size of the dielectric crystal grains is 80 nm or more and 160 nm or less.

8. The multilayer ceramic capacitor according to claim 1 , wherein the core portion contains a barium titanate-based main component containing barium (Ba) and titanium (Ti).

9. 2. The multilayer ceramic capacitor according to claim 1, wherein tin (Sn) is contained in the shell in an amount of 0.01 to 5 parts by mol per 100 parts by mol of the barium titanate-based main component.

10. The multilayer ceramic capacitor according to claim 1, wherein the auxiliary components further include dysprosium (Dy), terbium (Tb), manganese (Mn), vanadium (V), barium (Ba), silicon (Si), aluminum (Al), calcium (Ca), or a combination thereof.

11. For 100 mol parts of the barium titanate-based main component, The dysprosium (Dy) is contained in an amount of 0.01 molar parts or more and 5 molar parts or less, The terbium (Tb) is contained in an amount of 0.01 to 5 parts by mol, The manganese (Mn) is contained in an amount of 0.01 parts by mol or more and 5 parts by mol or less, The vanadium (V) is contained in an amount of 0.01 to 5 parts by mole, The barium (Ba) is contained in an amount of 0.01 to 5 parts by mol, The silicon (Si) is contained in an amount of 0.01 molar parts or more and 5 molar parts or less, The aluminum (Al) is contained in an amount of 0.01 to 5 parts by mol, The multilayer ceramic capacitor according to claim 10 , wherein the calcium (Ca) is contained in an amount of 0.01 parts by mol to 5 parts by mol.

12. A step of preparing a dielectric slurry by mixing a barium titanate-based main component powder and a subcomponent powder including a tin (Sn)-containing compound; preparing a dielectric green sheet using the dielectric slurry, and forming a conductive paste layer on a surface of the dielectric green sheet; laminating the dielectric green sheets having the conductive paste layers formed thereon to manufacture a dielectric green sheet laminate; sintering the dielectric green sheet laminate to produce a capacitor body including a dielectric layer and an internal electrode layer; and forming an external electrode on one surface of the capacitor body; the dielectric layer includes a plurality of dielectric crystal grains, at least one of the dielectric crystal grains includes a core portion and a shell portion surrounding at least a portion of the core portion, the shell portion includes an Sn-enriched region including tin (Sn) and an Sn-non-enriched region including tin (Sn) at a lower atomic percent than the Sn-enriched region; a ratio of tin (Sn) contained in the Sn-concentrated region to tin (Sn) contained in the Sn-non-concentrated region is 2.0 or more and 6.0 or less.

13. The method for producing a multilayer ceramic capacitor according to claim 12, wherein the tin (Sn)-containing compound is mixed in an amount of 0.01 to 5 parts by mol with respect to 100 parts by mol of the barium titanate-based main component powder.

14. 13. The method for producing a multilayer ceramic capacitor according to claim 12, wherein the auxiliary component powder further comprises a dysprosium (Dy)-containing compound, a terbium (Tb)-containing compound, a manganese (Mn)-containing compound, a vanadium (V)-containing compound, a barium (Ba)-containing compound, a silicon (Si)-containing compound, an aluminum (Al)-containing compound, a calcium (Ca)-containing compound, or a combination thereof.

15. For 100 mol parts of the barium titanate-based main component powder, The dysprosium (Dy)-containing compound is contained in an amount of 0.01 to 5 parts by mole, The terbium (Tb)-containing compound is contained in an amount of 0.01 to 5 parts by mole, The manganese (Mn)-containing compound is contained in an amount of 0.01 to 5 parts by mole, The vanadium (V)-containing compound is contained in an amount of 0.01 to 5 parts by mole, The barium (Ba)-containing compound is contained in an amount of 0.01 to 5 parts by mole, The silicon (Si)-containing compound is contained in an amount of 0.01 molar parts or more and 5 molar parts or less, The aluminum (Al)-containing compound is contained in an amount of 0.01 parts by mol or more and 5 parts by mol or less, The method for producing a multilayer ceramic capacitor according to claim 14, wherein the calcium (Ca)-containing compound is contained in an amount of 0.01 parts by mol to 5 parts by mol.

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