Multilayer ceramic capacitor and method of manufacturing the same

Abstract

The present disclosure provides a multilayer ceramic capacitor and a method of manufacturing the same, the multilayer ceramic capacitor including: a capacitor body including a dielectric layer and an inner electrode layer; and an external electrode disposed on an outer side of the capacitor body, in which the dielectric layer includes a plurality of dielectric grains, grain boundaries disposed between the plurality of dielectric grains, and a three-phase point at three grain boundary contacts, and the dielectric layer includes a second phase disposed at the three-phase point and including Dy, Al, and Si.

Description

Technical Field

[0001] This disclosure relates to a multilayer ceramic capacitor and a method for manufacturing the same. Background Technology

[0002] Ceramic electronic components include capacitors, inductors, piezoelectric elements, varistors, and thermistors. Among ceramic electronic components, multilayer ceramic capacitors (MLCCs) are used in various electronic devices due to their advantages such as small size, high capacitance, and ease of installation.

[0003] For example, multilayer ceramic capacitors (MLCCs) are chip capacitors that can be mounted on printed circuit boards of various electronic products, such as imaging devices (e.g., liquid crystal displays (LCDs), plasma display panels (PDPs), organic light-emitting displays (OLEDs), etc.), computers, personal portable terminals, smartphones, etc.) for charging or discharging from them.

[0004] Recently, as multilayer ceramic capacitors are used in various fields such as information technology (IT) and electrical engineering, there is a need to ensure more stringent temperature characteristics. Summary of the Invention

[0005] One aspect of this disclosure provides a multilayer ceramic capacitor with excellent high-temperature TCC (temperature coefficient of capacitance) characteristics and reliability.

[0006] Another aspect of this disclosure provides a method for manufacturing a multilayer ceramic capacitor.

[0007] One aspect of this disclosure provides a multilayer ceramic capacitor, the multilayer ceramic capacitor comprising: a capacitor body including a dielectric layer and an inner electrode layer; and an outer electrode disposed on the outer side of the capacitor body, wherein the dielectric layer includes a plurality of dielectric grains, grain boundaries disposed between the plurality of dielectric grains, and a three-phase point located at the contact of the three grain boundaries, the dielectric layer including a second phase disposed at the three-phase point, and the second phase including Dy, Al and Si.

[0008] Based on the total amount of atoms in the second phase, the second phase may include Dy in an amount of about 15 atomic% to about 25 atomic%.

[0009] Based on the total amount of atoms in the second phase, the second phase may include Al in an amount of about 5 atomic% to about 6 atomic%.

[0010] Based on the total amount of atoms in the second phase, the second phase may include Si in an amount of about 70 atomic% to about 80 atomic%.

[0011] The dielectric layer may include a barium titanate-based main component and secondary components including Dy, Al and Si.

[0012] The secondary components may also include one or more elements selected from Tb, V, Mn and Mg.

[0013] In the dielectric layer, based on 100 atomic parts of Ti in the barium titanate-based main component, Dy of the second phase may be included in an amount of about 0.95 atomic parts to about 1.15 atomic parts.

[0014] In the dielectric layer, based on 100 atomic parts of Ti in the barium titanate-based main component, Al of the second phase may be included in an amount of about 0.30 atomic parts to about 0.34 atomic parts.

[0015] In the dielectric layer, based on 100 atomic parts of Ti in the barium titanate-based main component, Si of the second phase may be included in an amount of about 4.0 to 4.4 atomic parts.

[0016] In the cross-section of the dielectric layer, the area occupied by the second phase may be from about 0.15% to about 1% of the total area of ​​the dielectric layer.

[0017] In the second phase, the amount of Al can be less than the amount of Dy.

[0018] In the second phase, the amount of Al can be less than the amount of Si.

[0019] In the second phase, the amount of Dy can be less than the amount of Si.

[0020] Another aspect of this disclosure provides a method for manufacturing a multilayer ceramic capacitor, the method comprising: mixing a barium titanate-based main component powder and a secondary component powder comprising a Dy-containing compound, an Al-containing compound, and a Si-containing compound to prepare a dielectric paste; using the dielectric paste to manufacture a dielectric green sheet and forming a conductive paste layer on the surface of the dielectric green sheet; manufacturing a dielectric green sheet stack by stacking a plurality of dielectric green sheets on which the conductive paste layer is formed; manufacturing a capacitor body comprising a dielectric layer and an inner electrode layer by firing the dielectric green sheet stack; and forming an outer electrode on the surface of the capacitor body, wherein the dielectric layer comprises a plurality of dielectric grains, grain boundaries disposed between the plurality of dielectric grains, and a triple point located at the contact of the three grain boundaries, the dielectric layer comprising a second phase disposed at the triple point, and the second phase comprising Dy, Al, and Si.

[0021] Based on 100 molar parts of the barium titanate-based main component powder, the Dy-containing compound can be mixed in an amount of about 0.5 molar parts to about 1.2 molar parts.

[0022] Based on 100 molar parts of the barium titanate-based main component powder, the Al-containing compound can be mixed in an amount of about 0.1 molar parts to about 0.5 molar parts.

[0023] Based on 100 moles of the barium titanate-based main component powder, the Si-containing compound can be mixed in an amount of about 1 mole to about 5 moles.

[0024] The secondary component powder may also include at least one selected from compounds containing Tb, V, Mn, and Mg.

[0025] It can be fired over a holding time of approximately 10 seconds to approximately 3 minutes.

[0026] It can be fired at a temperature of approximately 1160°C to approximately 1250°C.

[0027] The multilayer ceramic capacitor according to the embodiment can improve the high-temperature TCC (temperature coefficient of capacitance) characteristics while maintaining high reliability by suppressing the solid solution of additives into the barium titanate-based dielectric material. Attached Figure Description

[0028] Figure 1 This is a perspective view showing a multilayer ceramic capacitor according to an embodiment.

[0029] Figure 2 It is along Figure 1 A cross-sectional view of a multilayer ceramic capacitor taken by line I-I'.

[0030] Figure 3 It is along Figure 1 A cross-sectional view of a multilayer ceramic capacitor taken from line II-II'.

[0031] Figure 4 It is shown Figure 1 An exploded perspective view of the stacked structure of the capacitor body.

[0032] Figure 5 This is a schematic diagram showing a cross-section of the dielectric layer according to an embodiment.

[0033] Figures 6A to 6D The image is based on the TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) analysis of the dielectric layer in Example 1.

[0034] Figures 7A to 7D The images are based on TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) analysis of the dielectric layer of Comparative Example 1.

[0035] Figure 8 The graph shows the temperature coefficient of capacitance (TCC) of the multilayer ceramic capacitors based on Example 1, Comparative Example 1, and Comparative Example 2.

[0036] Figure 9 This is a graph illustrating the high-temperature harsh reliability of the multilayer ceramic capacitor according to Example 1.

[0037] Figure 10 This is a graph showing the high-temperature harsh reliability of the multilayer ceramic capacitor according to Comparative Example 1.

[0038] Figure 11 This is a graph showing the high-temperature harsh reliability of the multilayer ceramic capacitor according to Comparative Example 2.

[0039] Figure 12 This is a graph showing the moisture resistance reliability of the multilayer ceramic capacitor according to Example 1.

[0040] Figure 13 This is a graph showing the moisture resistance reliability of the multilayer ceramic capacitor according to Comparative Example 1.

[0041] Figure 14 This is a graph showing the moisture resistance reliability of the multilayer ceramic capacitor according to Comparative Example 2. Detailed Implementation

[0042] The present disclosure will now be described in detail with reference to the accompanying drawings, in which embodiments of the disclosure are illustrated. The drawings and description are to be considered illustrative rather than restrictive in nature. Throughout the specification, the same reference numerals denote the same elements. In the drawings, some components are exaggerated, omitted, or shown schematically, and the dimensions of each component do not perfectly reflect their actual dimensions.

[0043] The accompanying drawings are intended only to facilitate understanding of the embodiments disclosed in this specification, and it should be understood that the technical ideas disclosed herein are not limited to the drawings, and include all modifications, equivalents or alternatives within the scope of the ideas and techniques disclosed herein.

[0044] Although terms such as "first," "second," etc., are used to explain various components, components are not limited to these terms. These terms are only used to distinguish one component from another.

[0045] Furthermore, it should be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it may be directly on the other element, or there may be intermediate elements present. In contrast, when an element is referred to as being "directly on" another element, there are no intermediate elements present. Additionally, when an element is referred to as being "on" or "above" a reference element, it may be positioned above or below the reference element, and it does not necessarily mean being positioned "on" or "above" in a direction opposite to gravity.

[0046] Throughout this specification, the terms “comprising” or “having” are intended to specify the presence of the stated features, quantities, steps, operations, components, or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, steps, operations, components, and / or combinations thereof. Therefore, unless explicitly stated to the contrary, the word “comprising” and variations such as “including” or “containing” will be understood to imply the inclusion of the stated elements but not the exclusion of any other elements.

[0047] Furthermore, throughout the instruction manual, the phrase "in a plan view" or "on a plane" means viewing the target portion from the top, and the phrase "in a cross-sectional view" or "on a cross-section" means viewing the cross-section formed by vertically cutting the target portion from the side.

[0048] Throughout the specification, the term "connection" means not only that two or more constituent components are directly connected, but also that two or more constituent components are indirectly connected through another constituent component, that two or more constituent components are electrically connected and physically connected, or that two or more constituent components are referred to by different names according to their location or function but are formed as one unit.

[0049] In the following text, reference will be made to Figures 1 to 4 A multilayer ceramic capacitor according to an embodiment is described.

[0050] Figure 1 This is a perspective view showing a multilayer ceramic capacitor according to an embodiment. Figure 2 It is along Figure 1 A cross-sectional view of a multilayer ceramic capacitor taken by line I-I'. Figure 3 It is along Figure 1 A cross-sectional view of a multilayer ceramic capacitor taken from line II-II'. Figure 4 It is shown Figure 1 An exploded perspective view of the stacked structure of the capacitor body.

[0051] Figures 1 to 4The L-axis, W-axis, and T-axis shown represent the length, width, and thickness directions of the capacitor body 110, respectively. Here, the thickness direction (T-axis direction) can be perpendicular to the wide surface (main surface) of the sheet assembly and can be used as the same concept as, for example, the stacking direction of the stacked dielectric layers 111. The length direction (L-axis direction) can be parallel to the wide surface (main surface) of the sheet assembly and can be approximately perpendicular to the thickness direction (T-axis direction). For example, the length direction (L-axis direction) can be the direction in which the first external electrode 131 and the second external electrode 132 are opposite each other. The width direction (W-axis direction) can be parallel to the wide surface (main surface) of the sheet assembly and can be approximately perpendicular to both the thickness direction (T-axis direction) and the length direction (L-axis direction). The length of the sheet assembly in the length direction (L-axis direction) can be longer than its length in the width direction (W-axis direction).

[0052] Reference Figures 1 to 4 According to an embodiment, the multilayer ceramic capacitor 100 includes a capacitor body 110 and external electrodes 131 and 132 disposed on the outside of 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 opposite ends of the capacitor body 110 in the longitudinal direction (L-axis direction).

[0053] For example, the capacitor body 110 may have a generally hexahedral shape.

[0054] For ease of description of the embodiments, the two surfaces of the capacitor body 110 that are opposite to each other in the thickness direction (T-axis direction) are referred to as the first surface and the second surface, the two surfaces connected to the first surface and the second surface and opposite to each other in the length direction (L-axis direction) are referred to as the third surface and the fourth surface, and the two surfaces connected to the first surface and the second surface, and connected to the third surface and the fourth surface and opposite to each other in the width direction (W-axis direction) are referred to as the fifth surface and the sixth surface.

[0055] As an example, the first surface, which serves as the lower surface, can be a mounting surface. Alternatively, the first to sixth surfaces can be flat, but the embodiment is not limited to this. For example, the first to sixth surfaces can be curved surfaces with a convex central portion, and the edges that form the boundaries of each surface can be rounded.

[0056] The shape and size of the capacitor body 110 and the number of stacked dielectric layers 111 are not limited to the shape and size and the number of stacked layers shown in the accompanying drawings of the embodiment.

[0057] The capacitor body 110 includes a plurality of dielectric layers 111 and inner electrode layers 121 and 122. Specifically, the capacitor body 110 includes a plurality of dielectric layers 111 and a first inner electrode layer 121 and a second inner electrode layer 122, wherein the first inner electrode layer 121 and the second inner electrode layer 122 are alternately arranged in the thickness direction (T-axis direction) and the dielectric layer 111 is located between them.

[0058] At this point, the adjacent dielectric layers 111 of the capacitor body 110 can be integrated to such an extent that the boundaries between them are difficult to distinguish without the use of a scanning electron microscope (SEM).

[0059] The capacitor body 110 may include an effective area and coverage areas 112 and 113.

[0060] The effective region is the area where dielectric layer 111 and inner electrode layers 121 and 122 are alternately disposed, which helps to form the capacitance of the multilayer ceramic capacitor 100. Specifically, the effective region may be the area where the first inner electrode layer 121 and the second inner electrode layer 122 stacked along the thickness direction (T-axis direction) overlap.

[0061] Cover regions 112 and 113 are edges in the thickness direction and may be located on the upper and lower surfaces of the effective region in the thickness direction (T-axis direction), respectively. Cover regions 112 and 113 may be a single dielectric layer or two or more dielectric layers stacked on the upper and lower surfaces of the effective region, respectively.

[0062] In addition, the capacitor body 110 may also include a side edge region.

[0063] The side edge region is an edge portion in the width direction and can be located on opposite side ends (i.e., the fifth and sixth surfaces) of the effective region in the width direction (W-axis direction). The side edge region can be formed as follows: when a conductive paste layer for the inner electrode is coated on the surface of the dielectric green sheet, the conductive paste layer is coated only in a portion of the surface of the dielectric green sheet and no conductive paste layer is coated on the two sides of the surface of the dielectric green sheet, the dielectric green sheets are stacked and then fired, but the formation method is not limited to this.

[0064] Coverage areas 112 and 113, as well as side edge areas, are used to prevent damage to the first inner electrode layer 121 and the second inner electrode layer 122 due to physical stress and / or chemical stress.

[0065] Each of the dielectric layer, inner electrode layer, and outer electrode is described in detail below.

[0066] dielectric layer Reference Figure 5 The dielectric layer will be explained.

[0067] Figure 5 This is a schematic diagram showing a cross-section of the dielectric layer according to an embodiment.

[0068] Reference Figure 5 The dielectric layer 111 may include a plurality of dielectric grains 10, grain boundaries 20 disposed between the plurality of dielectric grains 10, and a triple point 30 located at the contact of the three grain boundaries 20. The triple point 30 refers to the point where the three grain boundaries 20 intersect each other, and the dielectric layer may include at least one triple point 30.

[0069] According to an embodiment, the dielectric layer 111 may include a second phase disposed at the triple point 30. Here, the second phase may include dysprosium (Dy), aluminum (Al), and silicon (Si).

[0070] The second phase can refer to a new phase precipitated after the firing of the dielectric green sheet stack. In other words, if the firing is carried out using a dielectric paste (which is prepared by mixing a barium titanate-based main component and a secondary component corresponding to the additives), additives such as rare earth elements may not dissolve into the barium titanate lattice, but precipitate out as a second phase.

[0071] In addition, Dy, Al and Si, which are included in the second phase, are chemically combined and exist in the form of compounds.

[0072] If there is more than one triple point 30 in the dielectric layer, the second phase may be included in at least one of the multiple triple points 30.

[0073] As the content of additives (e.g., rare earth elements such as Dy added together with the barium titanate-based main component to form the dielectric layer) increases, temperature characteristics (such as the temperature coefficient of capacitance (TCC)) may deteriorate. However, because of the effect on improving reliability, it is difficult to simply reduce the content of additives. Therefore, instead of reducing the content of additives, the embodiments improve temperature characteristics (such as TCC characteristics) by the solid solution difference of additives in the barium titanate-based main component, while still maintaining reliability characteristics. That is, according to the embodiments, when the second phase including Dy, Al and Si is located at the triple point 30 within the dielectric layer 111, the high-temperature TCC (temperature coefficient of capacitance) characteristics can be improved by suppressing the solid solution of additives in the barium titanate-based dielectric material, while maintaining high reliability.

[0074] The presence of a second phase comprising Dy, Al, and Si at the triple point 30 in dielectric layer 111 can be examined by TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy). Other methods and / or tools, as understood by those skilled in the art, may be used even if not described in this disclosure.

[0075] More specifically, after immersing the multilayer ceramic capacitor 100 in an epoxy resin mixture and then curing it, the W-axis and T-axis surfaces (WT surfaces) of the capacitor body 110 are polished to half a depth in the L-axis direction. A cross-sectional sample is then obtained by fixing and holding it in a vacuum chamber, allowing observation of the effective region where the dielectric layer 111 overlaps with the inner electrode layers 121 and 122. Next, the effective region of the cross-sectional sample can be measured using transmission electron microscopy (TEM), making at least one (e.g., one to five) of the dielectric layers 111 visible. For example, TEM can be performed using Xe-FIB (focused ion beam) at an accelerating voltage of 200 kV in a region of approximately 400 nm × 400 nm (where at least one dielectric layer 111 is visible in the effective region). Next, by performing EDS (energy dispersive spectroscopy) analysis on the TEM images of the measured cross-sectional samples, it was confirmed that a second phase including Dy, Al, and Si exists at the triple point (the point where any three grain boundaries intersect) within the dielectric layer 111.

[0076] Based on the total atomic content in the second phase, the second phase may include dysprosium (Dy) in an amount of about 15 atomic% to about 25 atomic% (e.g., about 17 atomic% to about 23 atomic%, about 18 atomic% to about 22 atomic%, or about 19 atomic% to about 21 atomic%). When the content of Dy in the second phase is within the said range, the solid solution of the additive in the barium titanate-based dielectric material can be suppressed, thereby improving the high-temperature TCC characteristics and maintaining excellent reliability characteristics.

[0077] Based on the total atomic content in the second phase, the second phase may include aluminum (Al) in an amount of about 5 atomic% to about 6 atomic% (e.g., about 5.1 atomic% to about 5.9 atomic%, about 5.2 atomic% to about 5.8 atomic%, or about 5.3 atomic% to about 5.7 atomic%). In the second phase, if the Al content is within the stated range, the solid solution of the additive in the barium titanate-based dielectric material can be suppressed, thereby improving high-temperature TCC characteristics and maintaining excellent reliability characteristics.

[0078] Based on the total atomic content in the second phase, the second phase may include silicon (Si) in an amount of about 70 atomic% to about 80 atomic% (e.g., about 72 atomic% to about 78 atomic%, about 73 atomic% to about 77 atomic%, or about 74 atomic% to about 76 atomic%). In the second phase, if the Si content is within the stated range, solid dissolution of additives in barium titanate-based dielectric materials can be suppressed, thereby improving high-temperature TCC characteristics and maintaining excellent reliability characteristics.

[0079] In the second phase, the amount of Al can be less than the amount of Dy.

[0080] In the second phase, the amount of Al can be less than the amount of Si.

[0081] In the second phase, the amount of Dy can be less than the amount of Si.

[0082] The dielectric layer 111 may include barium titanate-based main components and secondary components.

[0083] The barium titanate-based main component is a dielectric matrix with a high dielectric constant, and it contributes to the capacitance of the multilayer ceramic capacitor 100.

[0084] The barium titanate-based main component powder is a compound containing barium (Ba) and titanium (Ti), such as BaTiO3, Ba(Ti,Zr)O3, Ba(Ti,Sn)O3, (Ba,Ca)TiO3, (Ba,Ca)(Ti,Ca)O3, (Ba,Ca)(Ti,Zr)O3, (Ba,Ca)(Ti,Sn)O3, (Ba,Sr)TiO3, (Ba,Sr)(Ti,Zr)O3, (Ba,Sr)(Ti,Sn)O3, or combinations thereof.

[0085] The secondary components may include Dy, Al, and Si. The secondary components are different from the second phase present at the triple point 30 and may be present in at least one of the dielectric grains 10 and grain boundaries 20 in the dielectric layer 111.

[0086] The secondary components may also include one or more elements selected from terbium (Tb), vanadium (V), manganese (Mn) and magnesium (Mg).

[0087] In dielectric layer 111, based on 100 atomic parts of Ti in the barium titanate-based main component, the second phase Dy can be included in an amount of about 0.95 atomic parts to about 1.15 atomic parts (e.g., about 0.98 atomic parts to about 1.12 atomic parts or about 1.0 atomic parts to about 1.10 atomic parts). If the Dy content of the second phase in the entire dielectric layer is within the said range, the solid solution of the additive in the barium titanate-based dielectric material can be suppressed, thereby improving high-temperature TCC characteristics and maintaining excellent reliability characteristics.

[0088] In dielectric layer 111, based on 100 atomic parts of Ti in the barium titanate-based main component, Al in the second phase can be included in an amount of about 0.30 atomic parts to about 0.34 atomic parts (e.g., about 0.31 atomic parts to about 0.33 atomic parts). If the Al content in the second phase in the entire dielectric layer is within the said range, the solid solution of the additive in the barium titanate-based dielectric material can be suppressed, thereby improving high-temperature TCC characteristics and maintaining excellent reliability characteristics.

[0089] In dielectric layer 111, based on 100 atomic parts of Ti in the barium titanate-based main component, Si in the second phase can be included in an amount of about 4.0 atomic parts to about 4.4 atomic parts (e.g., about 4.1 atomic parts to about 4.3 atomic parts). Throughout the dielectric layer, if the Si content in the second phase is within the stated range, solid dissolution of the additive in the barium titanate-based dielectric material can be suppressed, thereby improving high-temperature TCC characteristics and maintaining excellent reliability characteristics.

[0090] In the cross-section of dielectric layer 111, the area occupied by the second phase can be from about 0.15% to about 1% of the total area of ​​the dielectric layer, for example, from about 0.18% to about 0.9%, from about 0.2% to about 0.8%, or from about 0.25% to about 0.7%. In the cross-section of dielectric layer 111, the total area of ​​the dielectric layer can be, for example, in the range of about 400 nm ± about 200 nm × about 400 nm ± about 200 nm, and the area occupied by the second phase is measured therein.

[0091] The Dy, Al, and Si contents in the dielectric layer, as well as the area of ​​the second phase, can be confirmed by TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy). Other methods and / or tools, as understood by those skilled in the art, may be used even if not described in this disclosure.

[0092] The average thickness (average length in the T-axis direction) of the dielectric layer 111 can be from about 0.1 μm to about 8.0 μm, and for example, from about 0.1 μm to about 6.0 μm. When the average thickness of the dielectric layer 111 is within the above range, the reliability of the multilayer ceramic capacitor can be improved.

[0093] The average thickness of dielectric layer 111 can be measured by placing the multilayer ceramic capacitor 100 in an epoxy resin mixture liquid, allowing it to cure, polishing it, then ion-milling it, and finally analyzing it using a scanning electron microscope (SEM). A scanning electron microscope, such as the Thermofisher Scientific Verios G4, can be used with measurement conditions of 10 kV and 0.2 nA, an analytical magnification of 100x, and can measure at least one, three, five, or ten or more dielectric layers 111. The average thickness of dielectric layer 111 can be obtained as an arithmetic mean by taking the center point of the dielectric layer 111 along its length (L-axis) or width (W-axis) as a reference point in the SEM image of the cross-sectional sample measured as described above, and taking the arithmetic mean of the thickness of dielectric layer 111 at 10 points spaced at predetermined intervals from the reference point. The spacing between the 10 points can be adjusted according to the size of the SEM image, and can be, for example, about 1 μm to about 100 μm, about 1 μm to about 50 μm, or about 1 μm to about 10 μm. In this case, all 10 points must be located within the dielectric layer 111, and if all 10 points are not located within the dielectric layer 111, the position of the reference point can be changed, or the spacing between the 10 points can be adjusted.

[0094] Inner electrode layer The inner electrode layers 121 and 122 (i.e., the first inner electrode layer 121 and the second inner electrode layer 122) are electrodes with different polarities and are alternately arranged to face each other along the T-axis direction, with a dielectric layer 111 between them, and the ends of the first inner electrode layer 121 and the second inner electrode layer 122 can be exposed through the third surface and the fourth surface of the capacitor body 110, respectively.

[0095] The first inner electrode layer 121 and the second inner electrode layer 122 are electrically insulated from each other by a dielectric layer 111 disposed in between.

[0096] The ends of the first inner electrode layer 121 and the second inner electrode layer 122, which are exposed through the third and fourth surfaces of the capacitor body 110, can be electrically connected to the first outer electrode 131 and the second outer electrode 132, respectively.

[0097] The first inner electrode layer 121 and the second inner electrode layer 122 include conductive metals and may include metals such as Ni, Cu, Ag, Pd, Au or alloys thereof, such as Ag-Pd alloys.

[0098] Additionally, the first inner electrode layer 121 and the second inner electrode layer 122 may include dielectric particles having the same composition as the ceramic material included in the dielectric layer 111.

[0099] The first inner electrode layer 121 and the second inner electrode layer 122 can be formed using a conductive paste comprising a conductive metal. The conductive paste can be printed using either screen printing or gravure printing.

[0100] The average thickness of the first inner electrode layer 121 and the second inner electrode layer 122 can be from about 0.1 μm to about 2 μm. The average thickness of the first inner electrode layer 121 and the second inner electrode layer 122 can be measured by scanning electron microscopy (SEM) analysis. Here, the scanning electron microscopy (SEM) analysis is the same as the method used to measure the average thickness of the dielectric layer 111 described above, so its description is omitted.

[0101] The capacitor body 110 can be formed by firing a stacked structure in which multiple dielectric layers 111 and internal electrode layers 121 and 122 are stacked.

[0102] external electrode The first external electrode 131 and the second external electrode 132 are provided with voltages of different polarities and can be electrically connected to the exposed portions of the first inner electrode layer 121 and the second inner electrode layer 122, respectively.

[0103] According to the above structure, when a predetermined voltage is applied to the first external electrode 131 and the second external electrode 132, charge accumulates between the first inner electrode layer 121 and the second inner electrode layer 122 that face each other. At this time, the capacitance of the multilayer ceramic capacitor 100 is proportional to the overlap area of ​​the first inner electrode layer 121 and the second inner electrode layer 122 that overlap each other along the T-axis direction in the effective region.

[0104] The first external electrode 131 may include: a first connecting portion disposed on the third surface of the capacitor body 110 and connected to the first inner electrode layer 121; and a first strip portion disposed on the edge where the third surface of the capacitor body 110 intersects with the first surface and the second surface and / or the fifth surface and the sixth surface, and the second external electrode 132 may include: a second connecting portion disposed on the fourth surface of the capacitor body 110 and connected to the second inner electrode layer 122; and a second strip portion disposed on the edge where the fourth surface of the capacitor body 110 intersects with the first surface and the second surface and / or the fifth surface and the sixth surface.

[0105] The first strip may extend from the first connecting portion to a portion of the first surface, a portion of the second surface, and / or a portion of the fifth surface and a portion of the sixth surface of the capacitor body 110. The second strip may extend from the second connecting portion to a portion of the first surface, a portion of the second surface, and / or a portion of the fifth surface and a portion of the sixth surface of the capacitor body 110. The first and second strips may be used to improve the adhesive strength between the first external electrode 131 and the second external electrode 132 and the capacitor body 110.

[0106] Each of the first external electrode 131 and the second external electrode 132 may include a sintered metal layer in contact with the capacitor body 110, a conductive resin layer configured to cover the sintered metal layer, and a plating layer configured to cover the conductive resin layer.

[0107] The sintered metal layer may include conductive metals and glass.

[0108] Conductive metals may 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, and for example, the term copper (Cu) may mean including copper (Cu) alloys. When the conductive metal includes copper (Cu), based on 100 molar parts of copper (Cu), metals other than copper (Cu) may be included in an amount of less than or equal to about 5 molar parts.

[0109] The glass may comprise a composition of mixed oxides (e.g., one or more selected from the group consisting of silicon oxide, boron oxide, aluminum oxide, transition metal oxides, alkali metal oxides, and alkaline earth metal oxides). The transition metal may be at least one selected from the group consisting of zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), and nickel (Ni); the alkali metal may be at least one selected from the group consisting of lithium (Li), sodium (Na), and potassium (K); and the alkaline earth metal may be at least one selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).

[0110] Optionally, the conductive resin layer may be formed on the sintered metal layer, and for example, may be formed in a shape that completely covers the sintered metal layer. Additionally, 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 may directly contact the capacitor body 110.

[0111] The conductive resin layer extends to the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110, and the length of the region (i.e., the strip portion) where the conductive resin layer extends and is disposed on the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110 may be longer than the length of the region (i.e., the strip portion) where the sintered metal layer extends and is disposed on the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110. In other words, the conductive resin layer may be formed on the sintered metal layer and may be formed in a shape that completely covers the sintered metal layer.

[0112] The conductive resin layer may include resin and conductive metal.

[0113] The resin included in the conductive resin layer can be, but is not limited to, a material having adhesive and shock-absorbing properties and capable of forming a paste when mixed with conductive metal powder. For example, the resin may include phenolic resin, acrylic resin, silicone resin, epoxy resin, or polyimide resin.

[0114] The conductive metal included in the conductive resin layer is used for electrical connection to the first inner electrode layer 121 and the second inner electrode layer 122 or the sintered metal layer.

[0115] The conductive metal included in the conductive resin layer may have a spherical shape, a sheet shape, or a combination thereof. That is, the conductive metal may be formed only in a sheet shape, only in a spherical shape, or in a mixed form of sheet and spherical shapes.

[0116] Here, spherical shape can also include shapes that are not perfect spheres, for example, shapes whose length ratio of the major axis to the minor axis (major axis / minor axis) is less than or equal to about 1.45. Sheet shape refers to a flat and elongated shape, without particular limitation. However, for example, the length ratio of the major axis to the minor axis (major axis / minor axis) can be greater than or equal to about 1.95.

[0117] The first external electrode 131 and the second external electrode 132 may further include a plating layer disposed on the outside of the conductive resin layer.

[0118] The coatings may be individual or in alloy form, including nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), or lead (Pb). For example, the coating may be a nickel (Ni) coating or a tin (Sn) coating, which may be in the form of nickel (Ni) coatings and tin (Sn) coatings stacked sequentially, or in the form of tin (Sn) coatings, nickel (Ni) coatings, and tin (Sn) coatings stacked sequentially. Alternatively, the coating may include multiple nickel (Ni) coatings and / or multiple tin (Sn) coatings.

[0119] The coating can improve the mounting properties, structural reliability, external durability, heat resistance and equivalent series resistance (ESR) of the multilayer ceramic capacitor 100 relative to the substrate.

[0120] Methods for manufacturing multilayer ceramic capacitors In the following, a method for manufacturing a multilayer ceramic capacitor 100 according to an embodiment will be described.

[0121] The multilayer ceramic capacitor 100 according to the embodiment can be manufactured by: mixing barium titanate-based main component powder and secondary component powder including Dy compound, Al compound and Si compound to prepare dielectric paste; using dielectric paste to manufacture dielectric green sheets and forming conductive paste layer on the surface of dielectric green sheets; manufacturing dielectric green sheet stack by stacking dielectric green sheets on which conductive paste layer is formed; manufacturing capacitor body including dielectric layer and inner electrode layer by firing dielectric green sheet stack; and forming outer electrode on the surface of capacitor body.

[0122] The barium titanate-based main component powder is a compound containing barium (Ba) and titanium (Ti), for example, it may include BaTiO3, Ba(Ti,Zr)O3, Ba(Ti,Sn)O3, (Ba,Ca)TiO3, (Ba,Ca)(Ti,Ca)O3, (Ba,Ca)(Ti,Zr)O3, (Ba,Ca)(Ti,Sn)O3, (Ba,Sr)TiO3, (Ba,Sr)(Ti,Zr)O3, (Ba,Sr)(Ti,Sn)O3, or combinations thereof.

[0123] The Dy-containing compounds, Al-containing compounds, and Si-containing compounds can each be oxides, nitrides, or salts, or they can be used in the form of sols dispersed in organic solvents.

[0124] Based on 100 moles of barium titanate-based main component powder, a Dy-containing compound can be mixed in an amount of about 0.5 moles to about 1.2 moles (e.g., about 0.6 moles to about 1.1 moles or about 0.7 moles to about 1.0 moles). If the Dy-containing compound is mixed within the said content range, the formation of a second phase can be induced, thus suppressing the solid solution of the additive in the barium titanate-based dielectric material, thereby improving high-temperature TCC characteristics and maintaining high reliability.

[0125] Based on 100 moles of barium titanate-based main component powder, an Al-containing compound can be mixed in an amount of about 0.1 moles to about 0.5 moles (e.g., about 0.2 moles to about 0.4 moles). If an Al-containing compound is mixed within this content range, the formation of a second phase can be induced, thus suppressing the solid solution of the additive in the barium titanate-based dielectric material, thereby improving high-temperature TCC characteristics and maintaining high reliability.

[0126] Based on 100 moles of barium titanate-based main component powder, a Si-containing compound can be mixed in amounts from about 1 mole to about 5 moles (e.g., from about 1.5 moles to about 4.5 moles or from about 2 moles to about 4 moles). If a Si-containing compound is mixed within the stated content range, the formation of a second phase can be induced, thus suppressing the solid solution of the additive in the barium titanate-based dielectric material, thereby improving high-temperature TCC characteristics and maintaining high reliability.

[0127] The secondary component powder may also include at least one selected from compounds containing Tb, V, Mn and Mg.

[0128] Dielectric pastes can be prepared by further mixing in additives such as dispersants, binders, plasticizers, lubricants, antistatic agents, and solvents.

[0129] The dispersant may include, for example, phosphate ester dispersants, polycarboxylic acid dispersants, or combinations thereof. Based on 100 parts by weight of a barium titanate-based compound, the dispersant can be mixed in amounts from about 0.1 parts by weight to about 5 parts by weight (e.g., from about 0.3 parts by weight to about 3 parts by weight). When the dispersant is mixed within the above-mentioned content range, the dielectric paste exhibits excellent dispersibility, and the amount of impurities included in the manufactured dielectric layer can be reduced.

[0130] The binder can be, for example, acrylic resin, polyvinyl butyl resin, polyvinyl alcohol acetal resin, ethyl cellulose resin, etc. Based on 100 parts by weight of barium titanate compound, the binder can be added in amounts from about 0.1 parts by weight to about 50 parts by weight (e.g., from about 3 parts by weight to about 30 parts by weight). When the binder is mixed within the above content range, the dielectric paste exhibits excellent dispersibility, and the amount of impurities included in the manufactured dielectric layer can be reduced.

[0131] Plasticizers can be, for example: phthalic acid compounds (such as dioctyl phthalate, benzyl butyl phthalate, dibutyl phthalate, dihexyl phthalate, di(2-ethylhexyl) phthalate, and di(2-ethylbutyl) phthalate); adipate compounds (such as dihexyl adipate and di(2-ethylhexyl) adipate); ethylene glycol compounds (such as ethylene glycol, diethylene glycol, and triethylene glycol); ethylene glycol ester compounds (such as triethylene glycol dibutyrate, triethylene glycol di(2-ethylbutyrate), and triethylene glycol di(2-ethylhexanoate)). Based on 100 parts by weight of barium titanate compound, the plasticizer can be added in an amount of about 0.1 parts by weight to about 20 parts by weight (e.g., about 1 part by weight to about 10 parts by weight). When plasticizers are mixed within the above-mentioned content range, the dielectric paste exhibits excellent dispersibility, and the amount of impurities included in the manufactured dielectric layer can be reduced.

[0132] Solvents can be: aqueous solvents (such as water); alcohol solvents (such as ethanol, methanol, benzyl alcohol, and methoxyethanol); ethylene glycol solvents (such as ethylene glycol and diethylene glycol); ketone solvents (such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone); ester solvents (such as butyl acetate, ethyl acetate, carbitol acetate, and butyl carbitol acetate); ether solvents (such as methyl cellosolve, ethyl cellosolve, butyl ether, and tetrahydrofuran); aromatic solvents (such as benzene, toluene, and xylene), etc. Considering the solubility or dispersibility of the various additives included in the dielectric paste, the solvent can be, for example, an alcohol solvent or an aromatic solvent. Based on 100 parts by weight of the barium titanate compound, the solvent can be mixed in amounts from about 50 parts by weight to about 1000 parts by weight (e.g., from about 100 parts by weight to about 500 parts by weight). When the solvent is mixed within the above-mentioned content range, the dielectric paste components can be sufficiently mixed, and subsequent solvent removal is easy.

[0133] The dielectric paste described above can be mixed using a wet ball mill or a stirred mill. When using zirconia balls in a wet ball mill, multiple zirconia balls with a diameter of about 0.1 mm to about 10 mm can be used for wet mixing for about 8 hours to about 48 hours or about 10 hours to about 24 hours.

[0134] The prepared dielectric paste forms a dielectric layer after firing.

[0135] As a method for forming the prepared dielectric paste into a sheet, a strip forming method such as the doctor blade method or the calendering roll method can be used. For example, a roll forming coating machine using the coating head discharge method can be used to form the prepared dielectric paste, and then the formed body can be dried to obtain a dielectric sheet.

[0136] To form a conductive paste layer that becomes the inner electrode layer after firing, the conductive paste can be prepared by mixing conductive powder made of conductive metals or alloys thereof, a binder, and a solvent. Additionally, barium titanate powder can be incorporated as a co-material if desired. The co-material helps to inhibit the sintering of the conductive powder during the firing process. In the step of manufacturing the dielectric green sheet, a dielectric paste can be prepared by mixing a barium titanate-based compound as the main component powder and optional secondary component powders.

[0137] The conductive powder may include nickel (Ni) or nickel (Ni) alloys.

[0138] Next, a dielectric green sheet stack is prepared by stacking multiple dielectric green sheets with internal electrode patterns formed thereon, and then pressing the multiple dielectric green sheets in the stacking direction. At this time, dielectric green sheets without internal electrode patterns can be stacked on the upper and lower surfaces of the dielectric green sheet stack in the stacking direction.

[0139] Optionally, the manufactured dielectric sheet stack can be cut into predetermined sizes by cutting or the like.

[0140] Additionally, if necessary, the dielectric green sheet stack can be cured and dried to remove plasticizers, etc., and after curing and drying, the dielectric green sheet stack can be tumble polished using a horizontal centrifugal tumbler or similar device. In tumble polishing, the dielectric green sheet stack is placed in a tumbler container containing a dielectric and polishing fluid, and rotational motion or vibration is applied to the tumbler container, thus polishing away unwanted parts (such as burrs generated during cutting). After tumble polishing, the dielectric green sheet stack can be washed with a cleaning solution such as water and then dried.

[0141] Subsequently, the capacitor body can be prepared after adhesive removal treatment (plasticization) and firing of the dielectric sheet stack.

[0142] The conditions for adhesive removal can be appropriately adjusted according to the composition of the dielectric layer or inner electrode layer. For example, the rate of temperature rise during the adhesive removal process can be from about 5°C / hour to about 300°C / hour, the holding temperature can be from about 180°C to about 400°C, and the temperature holding time can be from about 0.5 hours to about 24 hours. Adhesive removal can be carried out in an air atmosphere or a reducing atmosphere.

[0143] The firing conditions can be appropriately adjusted according to the main component composition of the dielectric layer or the inner electrode layer. For example, firing can be carried out at a temperature of about 1160°C to about 1250°C, such as about 1180°C to about 1240°C, about 1190°C to about 1230°C, or about 1200°C to about 1220°C. Furthermore, firing can be carried out with a holding time of about 10 seconds to about 3 minutes, such as about 20 seconds to about 2.5 minutes, about 30 seconds to about 2 minutes, or about 40 seconds to about 1.5 minutes. Additionally, firing can be carried out in a reducing atmosphere, such as in a humidified mixture of nitrogen and hydrogen, and under conditions such as a hydrogen concentration of less than or equal to about 1.0%. When the inner electrode layer comprises nickel (Ni) or a nickel (Ni) alloy, the oxygen partial pressure in the firing atmosphere can be about 1.0 × 10⁻⁶. -14 MPa to approximately 1.0 × 10 -10 MPa.

[0144] After firing, annealing can be performed as needed. Annealing is a process that re-oxidizes the dielectric layer, and it can be performed if firing is carried out in a reducing atmosphere. The annealing conditions can also be adjusted appropriately according to the composition of the dielectric layer. For example, the annealing temperature can be from about 950°C to about 1150°C, the time can be greater than about 0 hours and less than or equal to about 20 hours, and the heating rate can be from about 50°C / hour to about 500°C / hour. The annealing atmosphere can be a humidified nitrogen (N2) atmosphere, and the oxygen partial pressure can be about 1.0 × 10⁻⁶. -9 MPa to approximately 1.0 × 10 -5 MPa.

[0145] In the adhesive removal process, firing process, or annealing process, for example, a wetting agent (e.g., water) may be used to humidify the nitrogen or mixed gas. In this case, the temperature of the wetting agent (e.g., water temperature) may be from about 5°C to about 75°C. The adhesive removal process, firing process, and annealing process may be performed sequentially, or they may be performed separately.

[0146] Optionally, surface treatments (such as sandblasting, laser irradiation, tumble polishing, etc.) can be performed on the third and fourth surfaces of the prepared capacitor body 110. By performing this surface treatment, the ends of the first inner electrode layer and the second inner electrode layer can be exposed to the third and fourth surfaces, respectively, thereby improving the electrical connection between the first outer electrode and the first inner electrode layer and the electrical connection between the second outer electrode and the second inner electrode layer, and making it easier to form an alloy portion.

[0147] Subsequently, an external electrode is formed on the surface of the manufactured capacitor body 110.

[0148] As an example, a paste for forming a sintered metal layer can be applied to the capacitor body 110 and then sintered to form a sintered metal layer.

[0149] The paste used to form the sintered metal layer may include conductive metals and glass. Since the descriptions of conductive metals and glass are the same as described above, repeated descriptions will be omitted. Additionally, the paste used to form the sintered metal layer may optionally include binders, solvents, dispersants, plasticizers, oxide powders, etc. The binder may be, for example, ethyl cellulose resin, acrylic resin, butyral resin, etc., and the solvent may be, for example, an organic solvent (such as terpineol, butyl carbitol, ethanol, methyl ethyl ketone, acetone, toluene, etc.) or an aqueous solvent.

[0150] Methods for applying a paste for forming a sintered metal layer to the outer surface of the capacitor body 110 may include dipping, various printing methods (such as screen printing), coating methods using a dispenser, and spraying methods using a sprayer. The paste for forming the sintered metal layer may be applied to at least the third and fourth surfaces of the capacitor body 110, and optionally to portions of the first, second, fifth, and / or sixth surfaces on which the first and second external electrodes are formed.

[0151] Subsequently, the capacitor body 110 coated with paste for forming a sintered metal layer is dried and sintered at a temperature of about 700°C to about 1000°C for about 0.1 hours to about 3 hours to form a sintered metal layer.

[0152] Optionally, a paste for forming a conductive resin layer is applied to the outer surface of the obtained capacitor body 110 and then cured to form a conductive resin layer.

[0153] The paste used to form the conductive resin layer may include conductive metals and resins, and may optionally include non-conductive fillers. Since the descriptions of conductive metals and resins are the same as described above, they will not be repeated. Additionally, the paste used to form the conductive resin layer may optionally include binders, solvents, dispersants, plasticizers, oxide powders, etc. The binder may be, for example, ethyl cellulose resin, acrylic resin, butyral resin, etc., and the solvent may be an organic solvent (e.g., terpineol, butyl carbitol, ethanol, methyl ethyl ketone, acetone, and toluene) or an aqueous solvent.

[0154] For example, the conductive resin layer can be formed by immersing the capacitor body 110 in a paste for forming the conductive resin layer and then curing it, or by printing the paste for forming the conductive resin layer onto the surface of the capacitor body 110 using screen printing or gravure printing and then curing it, or by applying the paste for forming the conductive resin layer onto the surface of the capacitor body 110 and then curing it.

[0155] Next, a plating layer is formed on the outside of the conductive resin layer.

[0156] For example, a coating can be formed by plating, sputtering, or electroplating (electrodeposition).

[0157] The embodiments are described in more detail below with reference to examples. However, these examples are exemplary, and the scope of the claims is not limited thereto.

[0158] (Manufacturing of multilayer ceramic capacitors) Example 1 A dielectric paste is prepared by mixing barium titanate (BaTiO3) main component powder with secondary component powders (such as 1 mole of dysprosium oxide (Dy2O3), 0.3 mole of aluminum oxide (Al2O3), and 3 mole of silicon dioxide (SiO2) based on 100 moles of barium titanate (BaTiO3).

[0159] In the preparation of dielectric paste, zirconia spheres (ZrO2 spheres) are used as the dispersion medium, and ethanol / toluene and polyvinyl butyral (PVB) resin are added as wetting and dispersing agents and binders, followed by mechanical grinding for mixing.

[0160] Subsequently, dielectric green sheets are manufactured using dielectric paste by employing a coating head discharge type roller forming coating machine.

[0161] A conductive paste layer including nickel (Ni) is printed onto the surface of a dielectric green sheet, and the dielectric green sheets with the conductive paste layer formed thereon are stacked and pressed to manufacture a dielectric green sheet stack.

[0162] The dielectric green sheet stack is sintered in a nitrogen atmosphere at a temperature of 400°C or lower using a sintering process, and further sintered at a firing temperature of 1210°C and a holding time of 51 seconds under a hydrogen concentration of 0.11%, thereby forming the capacitor body.

[0163] Subsequently, external electrodes are formed on the surface of the capacitor body through processes such as plating to form external electrodes, thereby manufacturing a multilayer ceramic capacitor.

[0164] Comparative Example 1 Except for firing at a temperature of 1140°C and a holding time of 5 minutes under conditions of 0.11% hydrogen concentration, the multilayer ceramic capacitor was manufactured in the same manner as in Example 1.

[0165] Comparative Example 2 The multilayer ceramic capacitor was manufactured in the same manner as in Example 1, except that it was fired at a temperature of 1140°C and a holding time of 4 minutes under conditions of 0.11% hydrogen concentration.

[0166] Evaluation 1: TEM-EDS Analysis The multilayer ceramic capacitors fabricated in Example 1 and Comparative Example 1 were analyzed by TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy), and the results are shown in... Figures 6A to 6D as well as Figures 7A to 7D middle.

[0167] Specifically, a cross-sectional sample was obtained to allow observation of the effective region where the dielectric layer and inner electrode layer overlapped: The multilayer ceramic capacitors manufactured in Example 1 and Comparative Example 1 were immersed in an epoxy resin mixture and cured. The W-axis and T-axis surfaces (WT surfaces) of the capacitor body were polished to half the length along the L-axis, and then fixed and held in a vacuum chamber. Next, the effective region of the cross-sectional sample was measured using transmission electron microscopy (TEM), making at least one dielectric layer visible. TEM measurements were performed using Xe-FIB (focused ion beam) at an accelerating voltage of 200 kV in a region of approximately 400 nm × 400 nm (where at least one dielectric layer was visible in the effective region). Subsequently, EDS (energy-dispersive spectroscopy) analysis was performed on the measured TEM images of the cross-sectional sample.

[0168] Figures 6A to 6D The image is based on the TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) analysis of the dielectric layer in Example 1, and Figures 7A to 7D The images are based on TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) analysis of the dielectric layer of Comparative Example 1.

[0169] Reference Figures 6A to 6D In Example 1, a small amount of Dy was detected at the grain boundaries in the dielectric layer, and it was confirmed that a second phase comprising Dy, Al, and Si existed at the triple point where the three grain boundaries intersect. In contrast, Reference Figures 7A to 7D In Comparative Example 1, it was confirmed that Dy was mainly distributed at the grain boundaries, and no second phase including Dy, Al and Si was observed.

[0170] Evaluation 2: TCC characteristics The temperature coefficient of capacitance (TCC) characteristics of the multilayer ceramic capacitors according to Example 1, Comparative Examples 1 and 2 were measured, and the results are shown in... Figure 8 And in Table 1.

[0171] Specifically, the TCC was measured at 1 kHz, 0.01 V, and a holding time of 5 minutes.

[0172] (Table 1)

[0173] Figure 8 A graph showing the temperature coefficient of capacitance (TCC) of the multilayer ceramic capacitors of Example 1, Comparative Example 1, and Comparative Example 2 is shown.

[0174] Reference Figure 8As shown in Table 1, compared to Comparative Example 1, which did not have a second phase, and Comparative Example 2, which had a second phase including Si, Example 1, which had a second phase including Dy, Al, and Si at the triple point in the dielectric layer, exhibited a capacitance change of ±22% at both low and high temperatures compared to room temperature, thus demonstrating excellent TCC characteristics. This confirms that suppressing the solid solution of additives (such as rare earth elements) improves temperature characteristics (such as TCC characteristics). Therefore, the multilayer ceramic capacitor according to the embodiment exhibits excellent TCC characteristics.

[0175] Evaluation 3: Reliability The high-temperature harsh reliability (such as high-accelerated life test (HALT)) and moisture resistance reliability of the multilayer ceramic capacitors according to Example 1 and Comparative Examples 1 and 2 are measured, and the results are shown in Figures 9 to 14 middle.

[0176] Specifically, 40 multilayer ceramic capacitors according to Example 1 and Comparative Examples 1 and 2 were manufactured and then mounted on a measurement substrate to measure high-temperature harsh reliability (such as HALT) at 125°C, 12 hours and 9.45V using an ESPEC (PV-222, HALT) device, and moisture resistance reliability at 85°C, 85% relative humidity (RH), 9.45V and 12 hours using an ESPEC (PR-3J, 8585) device.

[0177] Figure 9 This is a graph illustrating the high-temperature harsh reliability of the multilayer ceramic capacitor according to Example 1. Figure 10 This is a graph showing the high-temperature harsh reliability of the multilayer ceramic capacitor according to Comparative Example 1, and Figure 11 This is a graph showing the high-temperature harsh reliability of the multilayer ceramic capacitor according to Comparative Example 2.

[0178] Reference Figures 9 to 11 Compared to Comparative Example 1, which did not have a second phase, and Comparative Example 2, which had a second phase including Si, Example 1, which had a second phase including Dy, Al, and Si at the triple point in the dielectric layer, exhibited equal or higher high-temperature harsh reliability. Therefore, the multilayer ceramic capacitor according to the embodiment exhibits excellent high-temperature harsh reliability.

[0179] Figure 12 This is a graph showing the moisture resistance reliability of the multilayer ceramic capacitor according to Example 1. Figure 13 This is a graph showing the moisture resistance reliability of the multilayer ceramic capacitor according to Comparative Example 1, and Figure 14 This is a graph showing the moisture resistance reliability of the multilayer ceramic capacitor according to Comparative Example 2.

[0180] Reference Figures 12 to 14Compared to Comparative Example 1, which did not have a second phase, and Comparative Example 2, which had a second phase including Si, Example 1, which had a second phase including Dy, Al, and Si at the triple point in the dielectric layer, exhibited equal or higher moisture resistance reliability. Therefore, the multilayer ceramic capacitor according to the embodiment exhibited excellent moisture resistance reliability.

[0181] While this disclosure has been described in conjunction with what is now considered to be actual embodiments, it should be understood that this disclosure is not limited to the disclosed embodiments, but is intended, by comparison, to cover various modifications and equivalents included within the spirit and scope of the appended claims.

Claims

1. A multilayer ceramic capacitor, comprising: The capacitor body includes a dielectric layer and an inner electrode layer; as well as The external electrode is disposed on the outside of the capacitor body. The dielectric layer includes a plurality of dielectric grains, grain boundaries disposed between the plurality of dielectric grains, and a three-phase point located at the contact point of the three grain boundaries. The dielectric layer includes a second phase disposed at the three-phase point, and The second phase includes Dy, Al and Si.

2. The multilayer ceramic capacitor according to claim 1, wherein, Based on the total amount of atoms in the second phase, the second phase includes Dy in an amount of 15 atomic% to 25 atomic% 3. The multilayer ceramic capacitor according to claim 1, wherein, Based on the total amount of atoms in the second phase, the second phase comprises Al in an amount of 5 to 6 atomic percent.

4. The multilayer ceramic capacitor according to claim 1, wherein, Based on the total atomic amount in the second phase, the second phase comprises Si in an amount of 70 atomic% to 80 atomic%.

5. The multilayer ceramic capacitor according to claim 1, wherein, The dielectric layer comprises a barium titanate-based main component and secondary components including Dy, Al, and Si.

6. The multilayer ceramic capacitor according to claim 5, wherein, The secondary components also include one or more elements selected from Tb, V, Mn and Mg.

7. The multilayer ceramic capacitor according to claim 5, wherein, In the dielectric layer, the second phase Dy is included in an amount of 0.95 to 1.15 atomic parts based on 100 atomic parts Ti in the barium titanate-based main component.

8. The multilayer ceramic capacitor according to claim 5, wherein, In the dielectric layer, the second phase Al is included in an amount of 0.30 to 0.34 atomic parts, based on 100 atomic parts of Ti in the barium titanate-based main component.

9. The multilayer ceramic capacitor according to claim 5, wherein, In the dielectric layer, Si of the second phase is included in an amount of 4.0 to 4.4 atomic parts, based on 100 atomic parts of Ti in the barium titanate-based main component.

10. The multilayer ceramic capacitor according to claim 1, wherein, In the cross-section of the dielectric layer, the area occupied by the second phase is 0.15% to 1% of the total area of ​​the dielectric layer.

11. The multilayer ceramic capacitor according to claim 1, wherein, In the second phase, the amount of Al is less than the amount of Dy.

12. The multilayer ceramic capacitor according to claim 1, wherein, In the second phase, the amount of Al is less than the amount of Si.

13. The multilayer ceramic capacitor according to claim 1, wherein, In the second phase, the amount of Dy is less than the amount of Si.

14. A method for manufacturing a multilayer ceramic capacitor, comprising: A dielectric paste is prepared by mixing barium titanate-based main component powder and secondary component powders including Dy-containing compounds, Al-containing compounds and Si-containing compounds; A dielectric green sheet is manufactured using the dielectric paste, and a conductive paste layer is formed on the surface of the dielectric green sheet; A dielectric sheet stack is manufactured by stacking multiple dielectric sheets on which the conductive paste layer is formed; A capacitor body comprising a dielectric layer and an inner electrode layer is manufactured by firing the dielectric green sheet stack; and An external electrode is formed on the surface of the capacitor body. The dielectric layer includes a plurality of dielectric grains, grain boundaries disposed between the plurality of dielectric grains, and a three-phase point located at the contact point of the three grain boundaries. The dielectric layer includes a second phase disposed at the three-phase point, and The second phase includes Dy, Al and Si.

15. The method according to claim 14, wherein, The Dy-containing compound is mixed in amounts ranging from 0.5 to 1.2 moles based on 100 moles of the barium titanate-based main component powder.

16. The method of claim 14, wherein, The Al-containing compound is mixed in amounts of 0.1 to 0.5 moles based on 100 moles of the barium titanate-based main component powder.

17. The method of claim 14, wherein, The Si-containing compound is mixed with 1 to 5 moles of the barium titanate-based main component powder based on 100 moles of the powder.

18. The method according to claim 14, wherein, The secondary component powder also includes at least one selected from compounds containing Tb, V, Mn, and Mg.

19. The method of claim 14, wherein, Firing is performed with a holding time of 10 seconds to 3 minutes.

20. The method of claim 14, wherein, Firing is carried out at a temperature of 1160°C to 1250°C.

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