Multilayer ceramic capacitor and method of manufacturing multilayer ceramic capacitor

Abstract

The disclosure provides a multilayer ceramic capacitor and a method of manufacturing a multilayer ceramic capacitor, the multilayer ceramic capacitor including: a ceramic main body including dielectric layers and having first and second surfaces opposite to each other, third and fourth surfaces connecting the first and second surfaces to each other, and fifth and sixth surfaces opposite to each other and connected to the first to fourth surfaces; a plurality of internal electrodes disposed in the ceramic main body, each exposed to the first and second surfaces and having one end exposed to the third or fourth surface; first and second side edge portions disposed on the first and second surfaces of the ceramic main body, respectively, wherein a metal or a metal oxide is disposed in each of the first and second side edge portions, and a ratio of a diameter of the metal or the metal oxide to a thickness of the dielectric layer is 0.8 or less.

Description

[0001] This application is a divisional application of the invention patent application "Multilayer ceramic capacitor and method for manufacturing multilayer ceramic capacitor" filed on January 2, 2019, with application number 201910001056.1. Technical Field

[0002] This disclosure relates to a multilayer ceramic capacitor and a method for manufacturing a multilayer ceramic capacitor, wherein the multilayer ceramic capacitor can have improved reliability by controlling the size of metal particles or metal oxides (e.g., nickel particles or nickel oxides) disposed in the side edges disposed on the side surface of a ceramic body. Background Technology

[0003] Typically, electronic components using ceramic materials (such as capacitors, inductors, piezoelectric elements, varistors, thermistors, etc.) include a ceramic body formed using ceramic materials, an internal electrode formed in the ceramic body, and an external electrode mounted on the surface of the ceramic body to connect to the internal electrode.

[0004] Recently, with the miniaturization and multifunctionality of electronic products, multilayer ceramic electronic components are also trending towards miniaturization and multifunctionality. Therefore, there is a need for multilayer ceramic capacitors with small size and high capacitance.

[0005] To miniaturize and increase the capacitance of multilayer ceramic capacitors, it is necessary to significantly increase the effective electrode area (increasing the effective volume fraction required to achieve capacitance).

[0006] To achieve the miniaturized and high-capacitance multilayer ceramic capacitors described above, a method has been used in the manufacture of multilayer ceramic capacitors to significantly increase the area of ​​the inner electrodes in the width direction of the body through a borderless design: by exposing the inner electrodes in the width direction of the body, and by individually attaching the side edges to the electrode-exposed surface in the width direction of the multilayer ceramic capacitor body during a process after manufacturing the multilayer ceramic capacitor body but before sintering.

[0007] However, in this method, during the formation of the side edge portion, the metal contained in the inner electrode or the oxide of the metal may be disposed in the side edge portion, which reduces the reliability of the multilayer ceramic capacitor due to the metal or the oxide of the metal.

[0008] In detail, the reduced distance between adjacent internal electrodes due to the metal or metal oxide contained in the side edge results in electric field concentration, leading to a short circuit.

[0009] Therefore, there is a need to research technologies that can improve the reliability of ultra-small and high-capacitance multilayer ceramic capacitors by preventing short circuits in multilayer ceramic capacitors. Summary of the Invention

[0010] One aspect of this disclosure provides a multilayer ceramic capacitor and a method for manufacturing a multilayer ceramic capacitor, wherein the multilayer ceramic capacitor can have improved reliability by controlling the size of metal particles or metal oxides (e.g., nickel particles or nickel oxides) disposed in the side edges disposed on the side surface of a ceramic body.

[0011] According to one aspect of this disclosure, a multilayer ceramic capacitor may include: a ceramic body including a dielectric layer and having a first surface and a second surface opposite to each other, a third surface and a fourth surface connecting the first surface and the second surface to each other, and a fifth surface and a sixth surface opposite to each other and connected to the first surface to the fourth surface; a plurality of internal electrodes disposed in the ceramic body, each exposed to the first surface and the second surface, and having one end exposed to the third surface or the fourth surface; and a first side edge portion and a second side edge portion respectively disposed on the first surface and the second surface of the ceramic body, wherein a metal or metal oxide is disposed in each of the first side edge portion and the second side edge portion, and the ratio of the diameter of the metal or the metal oxide to the thickness of the dielectric layer is 0.8 or less.

[0012] According to another aspect of this disclosure, a method for manufacturing a multilayer ceramic capacitor may include: preparing a first ceramic green sheet and a second ceramic green sheet, wherein a plurality of first internal electrode patterns are disposed on the first ceramic green sheet at predetermined intervals, and a plurality of second internal electrode patterns are disposed on the second ceramic green sheet at predetermined intervals; forming a ceramic green sheet multilayer by stacking the first ceramic green sheet and the second ceramic green sheet such that the first internal electrode patterns and the second internal electrode patterns alternate with each other; cutting the ceramic green sheet multilayer to have side surfaces that expose the ends of the first internal electrode patterns and the second internal electrode patterns in the width direction; forming a first side edge portion and a second side edge portion on the side surfaces that expose the ends of the first internal electrode patterns and the second internal electrode patterns, respectively; and preparing a ceramic body including a dielectric layer and internal electrodes by sintering the cut ceramic green sheet multilayer, wherein a metal or metal oxide is disposed in each of the first side edge portion and the second side edge portion, wherein the ratio of the diameter of the metal or the metal oxide to the thickness of the dielectric layer is 0.8 or less.

[0013] According to another aspect of this disclosure, a multilayer ceramic capacitor may include: a ceramic body including a dielectric layer, having a first surface and a second surface opposite to each other, a third surface and a fourth surface connecting the first surface and the second surface to each other, and a fifth surface and a sixth surface opposite to each other and connected to the first surface to the fourth surface; a plurality of internal electrodes disposed in the ceramic body, each exposed to the first surface and the second surface, and having one end exposed to the third surface or the fourth surface; and a first side edge portion and a second side edge portion respectively disposed on the first surface and the second surface of the ceramic body, wherein a metal or metal oxide is disposed in each of the first side edge portion and the second side edge portion, the diameter of the metal or the metal oxide being smaller than the thickness of each of the dielectric layers. Attached Figure Description

[0014] The above and other aspects, features and advantages of this disclosure will become more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0015] Figure 1 This is a schematic perspective view showing a multilayer ceramic capacitor according to an exemplary embodiment of the present disclosure;

[0016] Figure 2 It is shown Figure 1 A perspective view of the ceramic body's exterior;

[0017] Figure 3 This is shown in sintering Figure 2 A perspective view of the multi-layered ceramic sheet body preceding the ceramic body;

[0018] Figure 4 Is Figure 2 The side view when viewed from direction B;

[0019] Figure 5 This is a partial view of a cross-section of the ceramic body taken in the width-thickness direction at the central part in the length direction;

[0020] Figures 6A to 6F These are schematic cross-sectional views and schematic perspective views illustrating a method for manufacturing a multilayer ceramic capacitor according to another exemplary embodiment of this disclosure. Detailed Implementation

[0021] In the following, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0022] Figure 1 This is a schematic perspective view illustrating a multilayer ceramic capacitor according to exemplary embodiments of the present disclosure.

[0023] Figure 2It is shown Figure 1 A perspective view of the ceramic body's shape.

[0024] Figure 3 This is shown in sintering Figure 2 A perspective view of the multi-layered ceramic sheet body preceding the ceramic body.

[0025] Figure 4 Is Figure 2 The side view when viewed from direction B.

[0026] Reference Figures 1 to 4 According to this exemplary embodiment, the multilayer ceramic capacitor 100 may include a ceramic body 110, a plurality of internal electrodes 121 and 122 disposed in the ceramic body 110, and external electrodes 131 and 132 disposed on the outer surface of the ceramic body 110.

[0027] The ceramic body 110 may have a first surface 1 and a second surface 2 opposite to each other, a third surface 3 and a fourth surface 4 connecting the first surface and the second surface to each other, and a fifth surface 5 and a sixth surface 6 serving as the upper surface and the lower surface, respectively.

[0028] The first surface 1 and the second surface 2 refer to the surfaces of the ceramic body 110 that are opposite to each other in the width (W) direction (second direction), the third surface 3 and the fourth surface 4 refer to the surfaces of the ceramic body 110 that are opposite to each other in the length (L) direction (first direction), and the fifth surface 5 and the sixth surface 6 refer to the surfaces of the ceramic body 110 that are opposite to each other in the thickness (T) direction (third direction).

[0029] The shape of the ceramic body 110 is not particularly limited, but it can be a rectangular parallelepiped shape as shown.

[0030] One end of one of the plurality of internal electrodes 121 and 122 disposed in the ceramic body 110 may be exposed to the third surface 3 or the fourth surface 4 of the ceramic body 110.

[0031] The internal electrodes 121 and 122 may include a pair of first internal electrodes 121 and second internal electrodes 122 with different polarities.

[0032] One end of the first inner electrode 121 can be exposed to the third surface 3, and one end of the second inner electrode 122 can be exposed to the fourth surface 4.

[0033] The other end of the first inner electrode 121 and the second inner electrode 122 may be configured to be separated from the third surface 3 or the fourth surface 4 by a predetermined interval.

[0034] The first external electrode 131 and the second external electrode 132 can be respectively disposed on the third surface 3 and the fourth surface 4 of the ceramic body 110, and can be electrically connected to the internal electrode.

[0035] A multilayer ceramic capacitor 100 according to an exemplary embodiment of the present disclosure may include a plurality of inner electrodes 121 and 122 and a first side edge portion 112 and a second side edge portion 113. The plurality of inner electrodes 121 and 122 are disposed in a ceramic body 110, exposed to a first surface 1 and a second surface 2, and have one end exposed to a third surface 3 or a fourth surface 4. The first side edge portion 112 and the second side edge portion 113 are respectively disposed on the side portions of the inner electrodes 121 and 122 exposed to the first surface 1 and the second surface 2.

[0036] Multiple internal electrodes 121 and 122 may be disposed in the ceramic body 110, and corresponding side portions of the multiple internal electrodes 121 and 122 may be exposed to the first surface 1 and the second surface 2 (the surface of the ceramic body 110 in the width direction), and the first side edge portion 112 and the second side edge portion 113 may be disposed on the exposed side portions.

[0037] The average thickness of each of the first side edge portion 112 and the second side edge portion 113 may be greater than or equal to 2 μm and less than or equal to 10 μm.

[0038] According to exemplary embodiments of the present disclosure, the ceramic body 110 may include a laminate in which a plurality of dielectric layers 111 are stacked, and a first side edge portion 112 and a second side edge portion 113 respectively disposed on opposite side surfaces of the laminate.

[0039] Multiple dielectric layers 111 can be in a sintered state, and adjacent dielectric layers can be integrated with each other, making the boundaries between them less obvious.

[0040] The length of the ceramic body 110 can correspond to the distance from the third surface 3 of the ceramic body 110 to the fourth surface 4 of the ceramic body 110.

[0041] The length of the dielectric layer 111 can form the distance between the third surface 3 and the fourth surface 4 of the ceramic body 110.

[0042] According to exemplary embodiments in this disclosure, the length of the ceramic body 110 may be from 400 μm to 1400 μm, but is not limited thereto. More specifically, the length of the ceramic body 110 may be from 400 μm to 800 μm or from 600 μm to 1400 μm.

[0043] The inner electrodes 121 and 122 can be disposed on the dielectric layer 111. The inner electrodes 121 and 122 can be disposed in the ceramic body 110 by sintering, and the dielectric layer is located between the inner electrodes 121 and 122.

[0044] Reference Figure 3The first inner electrode 121 may be disposed on the dielectric layer 111. The first inner electrode 121 may not be completely disposed on the dielectric layer in the length direction of the dielectric layer. That is, one end of the first inner electrode 121 may be configured to extend to the third surface 3 to expose the third surface 3, and the other end of the first inner electrode 121 may be configured to be separated from the fourth surface 4 of the ceramic body 110 by a predetermined distance.

[0045] The end portion of the first inner electrode exposed to the third surface 3 of the ceramic body 110 can be connected to the first outer electrode 131.

[0046] In contrast to the first inner electrode, one end of the second inner electrode 122 may be exposed to the fourth surface 4 to connect to the second outer electrode 132, and the other end of the second inner electrode 122 may be configured to be separated from the third surface 3 by a predetermined interval.

[0047] To achieve high-capacitance multilayer ceramic capacitors, 400 or more internal electrodes can be stacked, but the number of internal electrodes is not limited to this.

[0048] The dielectric layer 111 may have the same width as the first inner electrode 121. That is, the first inner electrode 121 may be completely disposed on the dielectric layer 111 in the width direction.

[0049] According to exemplary embodiments in this disclosure, the width of the dielectric layer and the width of the inner electrode can be from 100 μm to 900 μm, but are not limited thereto. More specifically, the width of the dielectric layer and the width of the inner electrode can be from 100 μm to 500 μm or from 100 μm to 900 μm.

[0050] Because the ceramic body is miniaturized, the thickness of each of the side edges affects the electrical characteristics of the multilayer ceramic capacitor. According to exemplary embodiments of this disclosure, each of the side edges can be formed with a thickness of 10 μm or less, thereby improving the characteristics of the miniaturized multilayer ceramic capacitor.

[0051] In other words, each of the side edges can be formed with a thickness of 10 μm or less, thereby ensuring as much stacked area as possible between the internal electrodes to form a capacitor, in order to achieve a high-capacitance and miniaturized multilayer ceramic capacitor.

[0052] The ceramic body 110 may include an effective part A that contributes to the capacitance of the capacitor, and an upper cover part 114 and a lower cover part 115 respectively disposed on the upper and lower surfaces of the effective part A as an upper edge part and a lower edge part.

[0053] The effective part A can be formed by repeatedly stacking a plurality of first internal electrodes 121 and a plurality of second internal electrodes 122, with a dielectric layer 111 between the first internal electrodes 121 and the second internal electrodes 122.

[0054] Except that the upper cover portion 114 and the lower cover portion 115 do not include internal electrodes, the upper cover portion 114 and the lower cover portion 115 may be formed using the same material as the dielectric layer 111 and have the same structure as the dielectric layer 111.

[0055] In other words, the upper cover 114 and the lower cover 115 may contain ceramic materials, such as barium titanate (BaTiO3) based ceramic materials.

[0056] Each of the upper cover portion 114 and the lower cover portion 115 may have a thickness of 20 μm or less, but is not necessarily limited to this.

[0057] In exemplary embodiments of this disclosure, the inner electrode and dielectric layer, which are simultaneously cut and formed, can be formed with the same width. This will be described in more detail below.

[0058] In this exemplary embodiment, the dielectric layer may be formed to have the same width as the inner electrode, so that the side portions of the inner electrodes 121 and 122 may be exposed to the first and second surfaces of the ceramic body 110 in the width direction.

[0059] The first side edge portion 112 and the second side edge portion 113 may be respectively disposed on opposite side surfaces in the width direction of the ceramic body 110, and the side portions of the inner electrodes 121 and 122 are exposed to the opposite side surfaces.

[0060] Each of the first side edge portion 112 and the second side edge portion 113 may have a thickness of 10 μm or less. In the case of a multilayer ceramic capacitor of the same size, the smaller the thickness of each of the first side edge portion 112 and the second side edge portion 113, the larger the stacking area between the inner electrodes disposed in the ceramic body 110.

[0061] The thickness of each of the first side edge portion 112 and the second side edge portion 113 is not specifically limited, as long as it prevents short circuits between the inner electrodes exposed to the side surface of the ceramic body 110, and for example, it can be 2 μm or greater.

[0062] When the thickness of each of the first side edge portion 112 and the second side edge portion 113 is less than 2 μm, the mechanical strength against external impact will decrease. When the thickness of each of the first side edge portion 112 and the second side edge portion 113 exceeds 10 μm, the stacking area between the inner electrodes will be relatively reduced, making it difficult to ensure the high capacitance of the multilayer ceramic capacitor.

[0063] To significantly improve the capacitance of multilayer ceramic capacitors, methods have been considered such as reducing the thickness of each dielectric layer, increasing the number of stacked dielectric layers (with reduced thickness of each dielectric layer), and increasing the coverage of each internal electrode.

[0064] In addition, methods to increase the stacking area for forming capacitance between internal electrodes have been considered.

[0065] To increase the overlapping area between the inner electrodes, it is necessary to significantly reduce the edge regions where no inner electrodes are located.

[0066] Specifically, as multilayer ceramic capacitors are miniaturized, the edge regions need to be significantly reduced to increase the stacking area between the internal electrodes.

[0067] According to this exemplary embodiment, the inner electrodes can be configured to spread throughout the entire dielectric layer in the width direction of the dielectric layer, and the thickness of each of the side edges can be configured to be 10 μm or less, so that the stacking area between the inner electrodes can be large.

[0068] Typically, as the number of stacked dielectric layers increases, the thickness of the dielectric layers and internal electrodes decreases. Therefore, internal electrode short circuits frequently occur. Furthermore, when the internal electrode is only located on a portion of the dielectric layer, steps are created due to the internal electrode, which reduces the insulation resistance or reliability of the multilayer ceramic capacitor.

[0069] However, according to this exemplary embodiment, even if an inner electrode and a dielectric layer formed using a thin film are formed, the inner electrode can be completely disposed on the dielectric layer in the width direction of the dielectric layer, so the stacking area between the inner electrodes can be increased, thereby increasing the capacitance of the multilayer ceramic capacitor.

[0070] Furthermore, it can reduce the steps caused by the internal electrodes, thereby improving the insulation resistance, and can provide multilayer ceramic capacitors with excellent capacitance characteristics and excellent reliability.

[0071] Figure 5 This is a partial view of a cross-section of a ceramic body taken in the width-thickness direction at the central part in the length direction.

[0072] Reference Figure 5 In the multilayer ceramic capacitor according to the exemplary embodiments of the present disclosure, a metal or metal oxide 21 may be provided in the first side edge portion 112 and the second side edge portion 113, and the ratio of the diameter D of the metal or metal oxide 21 to the thickness td of the dielectric layer 111 may be 0.8 or less.

[0073] When, as in the exemplary embodiments of this disclosure, in a process prior to sintering in the manufacturing process of a multilayer ceramic capacitor, the side edge portion is individually attached to the electrode exposed surface of the ceramic body 110 in the width direction, the metal or oxide of the metal included in the inner electrode may be disposed in the side edge portion during the process of forming the side edge portion, and the reliability of the multilayer ceramic capacitor may decrease due to the metal or the oxide of the metal.

[0074] In detail, the reduction in distance between the internal electrodes due to the metal or metal oxide generated in the side edge leads to electric field concentration, resulting in a short circuit.

[0075] In other words, when the neutral conductor penetrates between the inner electrodes with a potential difference, the charges in the neutral conductor can be rearranged according to the properties of the neutral conductor, and the neutral conductor with rearranged charges can have the same effect as the electrodes, reducing the distance between the inner electrodes and thus increasing the electric field strength between the inner electrodes.

[0076] When a metal or metal oxide that acts as a neutral conductor penetrates into the side edge, the likelihood of a short circuit increases due to the increased electric field strength between the internal electrodes.

[0077] According to an exemplary embodiment of this disclosure, the particle size of the metal or metal oxide 21 generated in each of the first side edge portion 112 and the second side edge portion 113 can be controlled to predict the amount of electric field concentration, thereby reducing short circuits.

[0078] In detail, a metal or metal oxide 21 may be disposed in each of the first side edge portion 112 and the second side edge portion 113, and the ratio of the diameter D of the metal or metal oxide 21 to the thickness td of the dielectric layer 111 may be controlled to be 0.8 or less, so as to control the increased electric field in the inner electrode and reduce short circuits.

[0079] Metal or metal oxide 21 may be disposed in each of the first side edge portion 112 and the second side edge portion 113, and when the ratio of the diameter D of the metal or metal oxide 21 to the thickness td of the dielectric layer 111 exceeds 0.8, the diameter D of the metal or metal oxide 21, which has the same function as the electrode, will increase, thereby reducing the distance between the inner electrodes and causing a short circuit.

[0080] On the other hand, in the exemplary embodiments of this disclosure, the smaller the diameter D of the metal or metal oxide 21, the lower the probability of a short circuit occurring. Therefore, the lower limit of the ratio of the diameter D of the metal or metal oxide 21 to the thickness td of the dielectric layer 111 is not specifically limited.

[0081] In the metal or metal oxide 21, the metal can be nickel (Ni) and the metal oxide can be an oxide containing nickel (Ni) and magnesium (Mg), but the metal or metal oxide 21 is not limited to this.

[0082] When the first inner electrode 121 and the second inner electrode 122 contain nickel (Ni), as described above, the metal or metal oxide 21 disposed in each of the first side edge portion 112 and the second side edge portion 113 can be nickel (Ni) or an oxide containing nickel (Ni) and magnesium (Mg).

[0083] As another example, when the first inner electrode 121 and the second inner electrode 122 contain metals other than nickel (Ni), the metal or metal oxide 21 disposed in each of the first side edge portion 112 and the second side edge portion 113 may also be the metal other than nickel (Ni) or an oxide of the metal.

[0084] Metal or metal oxide 21 may be disposed in the regions adjacent to dielectric layer 111 of the first side edge portion 112 and the second side edge portion 113.

[0085] In an exemplary embodiment of this disclosure, as described above, since the metal or metal oxide 21 can penetrate into each of the first side edge portion 112 and the second side edge portion 113 when the side edge portions are individually attached to the electrode exposed surface in the width direction of the ceramic body 110 during the process prior to sintering, and there is a limitation on the diffusion of the metal or metal oxide 21 into each of the side edge portions, the metal or metal oxide 21 can be disposed in the regions of the first side edge portion 112 and the second side edge portion 113 adjacent to the dielectric layer 111.

[0086] Specifically, the regions of the first side edge portion 112 and the second side edge portion 113 adjacent to the dielectric layer 111 may be the regions located between the first inner electrode 121 and the second inner electrode 122.

[0087] When the metal or metal oxide 21 is disposed in the region between the first inner electrode 121 and the second inner electrode 122 in the region adjacent to the dielectric layer 111 of the first side edge portion 112 and the second side edge portion 113, an electric field concentration will be generated between the inner electrodes.

[0088] In other words, when no separate edge portion is attached, as in the method of manufacturing a multilayer ceramic capacitor according to the prior art, the probability that a metal or metal oxide will be disposed in the edge portion of the ceramic body in the width direction is low, and the probability that a metal or metal oxide will be specifically disposed in the edge portion of the ceramic body adjacent to the dielectric layer in the width direction is low.

[0089] Therefore, the feature of metal or metal oxide 21 being disposed in the region adjacent to dielectric layer 111 of the first side edge portion 112 and the second side edge portion 113 may be a unique phenomenon of this disclosure. In an exemplary embodiment of this disclosure, the diameter of metal or metal oxide 21 can be controlled to control the electric field concentration between the inner electrodes, thereby reducing short circuits.

[0090] Specifically, the multilayer ceramic capacitor according to the exemplary embodiments of this disclosure can be an ultra-miniature and high-capacitance multilayer ceramic capacitor in which the thickness of the dielectric layer 111 is 0.4 μm or less and the thickness of each of the inner electrodes 121 and 122 is 0.4 μm or less.

[0091] In exemplary embodiments of this disclosure, where an ultra-miniature and high-capacitance multilayer ceramic capacitor is used, which utilizes a dielectric layer 111 formed with a thin film having a thickness of 0.4 μm or less and inner electrodes 121 and 122, reliability issues due to short circuits caused by electric field concentration between the inner electrodes are a very important problem.

[0092] In other words, compared to multilayer ceramic capacitors according to the prior art, the technology according to the exemplary embodiments of this disclosure is applied to ultra-miniature and high-capacitance multilayer ceramic capacitors in which the thickness of the dielectric layer 111 is 0.4 μm or less and the thickness of each of the inner electrodes 121 and 122 is 0.4 μm or less. In such ultra-miniature and high-capacitance multilayer ceramic capacitors, the thickness of the dielectric layer is small, resulting in a small distance between the inner electrodes, which increases the likelihood of electric field concentration.

[0093] In addition to the aforementioned problems of ultra-small and high-capacitance multilayer ceramic capacitors, in the exemplary embodiments of this disclosure, the side edges can also be individually attached to the electrode-exposed surfaces of the ceramic body 110 in the width direction during a process prior to sintering. Therefore, in the process of forming the side edges, the metal or metal oxide contained in the inner electrode can be disposed in the side edges.

[0094] In this case, as described above, metals or metal oxides can be used as electrodes, resulting in an effect that further reduces the distance between the internal electrodes. Therefore, the possibility of a short circuit due to electric field concentration is further increased.

[0095] However, as in the exemplary embodiments of this disclosure, in the ultra-small and high-capacitance multilayer ceramic capacitor in which separate side edges are attached, the ratio of the diameter D of the metal or metal oxide 21 to the thickness td of the dielectric layer 111 can be controlled to be 0.8 or less, so that even when the dielectric layer 111 and the first inner electrode 121 and the second inner electrode 122 are formed using a thin film with a thickness of 0.4 μm or less, the reliability of the multilayer ceramic capacitor can be improved.

[0096] However, the thin film does not mean that the thickness of the dielectric layer 111 and the first inner electrode 121 and the second inner electrode 122 is 0.4 μm or less, but can conceptually include: the thickness of the dielectric layer and the inner electrode is less than the thickness of the dielectric layer and the inner electrode of the multilayer ceramic capacitor according to the prior art.

[0097] In an exemplary embodiment of this disclosure, in a method for controlling the ratio of the diameter D of the metal or metal oxide 21 to the thickness td of the dielectric layer 111 to be 0.8 or less, the diameter D of the metal or metal oxide 21 can be controlled by controlling the sintering temperature profile or controlling the temperature rise rate in a sintering process after the first side edge portion 112 and the second side edge portion 113 are disposed on the side surface of the ceramic body 110 in the width direction.

[0098] Reference Figure 4 The ratio of the thickness tc2 of the region where the end of the inner electrode of the first side edge portion 112 or the second side edge portion 113 is disposed in the outermost part of the ceramic body 110 in the direction of stacking of multiple inner electrodes to the thickness tc1 of the region where the end of the inner electrode of the first side edge portion 112 or the second side edge portion 113 is disposed in the central ... direction of stacking of multiple inner electrodes to the thickness tc1 of the region where the end of the inner electrode of the first

[0099] The lower limit of the ratio of the thickness tc2 of the area where the first side edge portion 112 or the second side edge portion 113 contacts the end of the inner electrode located at the outermost portion to the thickness tc1 of the area where the first side edge portion 112 or the second side edge portion 113 contacts the end of the inner electrode located at the central portion is not particularly limited, and may be 0.9 or greater.

[0100] According to exemplary embodiments of the present disclosure, since, unlike the prior art, the first side edge portion 112 or the second side edge portion 113 can be formed by attaching a ceramic green sheet to the side surface of the ceramic body, and therefore, the thickness of the first side edge portion 112 or the second side edge portion 113 at each location can be constant.

[0101] In other words, in the prior art, the side edges are formed by coating or printing ceramic paste, resulting in large variations in the thickness of the side edges at each location.

[0102] In detail, in the prior art, the thickness of the area of ​​the first or second side edge that contacts the end of the inner electrode located in the central part of the ceramic body is greater than the thickness of other areas.

[0103] For example, in the prior art, the ratio of the thickness of the area of ​​the first or second side edge portion that contacts the end of the inner electrode located at the outermost portion to the thickness of the area of ​​the first or second side edge portion that contacts the end of the inner electrode located at the central portion is less than about 0.9, resulting in a large thickness deviation.

[0104] In the prior art, where the thickness deviation of the side edge portion at each location is large, the portion occupied by the side edge portion in a multilayer ceramic capacitor of the same size is large, making it impossible to ensure a large capacitor forming portion, thus making it difficult to ensure high capacitance.

[0105] On the other hand, in the exemplary embodiments of this disclosure, the average thickness of each of the first side edge portion 112 and the second side edge portion 113 can be greater than or equal to 2 μm and less than or equal to 10 μm, and the ratio of the thickness tc2 of the region of the first side edge portion 112 or the second side edge portion 113 that contacts the end of the inner electrode disposed at the outermost portion to the thickness tc1 of the region of the first side edge portion 112 or the second side edge portion 113 that contacts the end of the inner electrode disposed at the central portion of the plurality of inner electrodes 121 and 122 can be greater than or equal to 0.9 and less than or equal to 1.0. Therefore, the thickness of the side edge portion can be small and the thickness deviation of the side edge portion can be small, thereby ensuring a large-size capacitor forming portion.

[0106] In an exemplary embodiment of this disclosure, unlike the prior art, the first side edge 112 or the second side edge 113 can be formed by attaching a ceramic green sheet to the side surface of the ceramic body. Therefore, the thickness of the first side edge 112 or the second side edge 113 at each location can be constant.

[0107] Therefore, high-capacitance multilayer ceramic capacitors can be realized.

[0108] At the same time, refer to Figure 4 The ratio of the thickness tc3 of the area of ​​the first side edge portion 112 or the second side edge portion 113 that contacts the edge of the ceramic body 110 to the thickness tc1 of the area of ​​the first side edge portion 112 or the second side edge portion 113 that contacts the end of the inner electrode of the plurality of inner electrodes 121 and 122 located in the central portion may be 1.0 or less.

[0109] The lower limit of the ratio of the thickness tc3 of the area of ​​the first side edge portion 112 or the second side edge portion 113 that contacts the edge of the ceramic body 110 to the thickness tc1 of the area of ​​the first side edge portion 112 or the second side edge portion 113 that contacts the end of the inner electrode disposed in the central portion can be 0.9 or greater.

[0110] Due to the aforementioned characteristics, the thickness variation of the side edge portion in each region can be small, ensuring the formation of large-sized capacitor sections. Therefore, high-capacitance multilayer ceramic capacitors can be realized.

[0111] Figures 6A to 6F These are schematic cross-sectional views and schematic perspective views illustrating a method for manufacturing a multilayer ceramic capacitor according to another exemplary embodiment of this disclosure.

[0112] According to another exemplary embodiment of this disclosure, a method of manufacturing a multilayer ceramic capacitor may include: preparing a first ceramic green sheet having a plurality of first internal electrode patterns disposed thereon at predetermined intervals and a second ceramic green sheet having a plurality of second internal electrode patterns disposed thereon at predetermined intervals; forming a ceramic green sheet multilayer by stacking the first ceramic green sheet and the second ceramic green sheet such that the first internal electrode patterns and the second internal electrode patterns alternate with each other; cutting the ceramic green sheet multilayer to have side surfaces that expose the ends of the first internal electrode patterns and the second internal electrode patterns in the width direction; forming a first side edge portion and a second side edge portion on the side surfaces that expose the ends of the first internal electrode patterns and the second internal electrode patterns, respectively; and preparing a ceramic body including a dielectric layer and first internal electrodes and second internal electrodes by sintering the cut ceramic green sheet multilayer, wherein a metal or metal oxide is disposed in each of the first side edge portion and the second side edge portion, the ratio of the diameter of the metal or metal oxide to the thickness of the dielectric layer being 0.8 or less.

[0113] In the following, a method for manufacturing a multilayer ceramic capacitor according to another exemplary embodiment of the present disclosure will be described.

[0114] like Figure 6A As shown, a plurality of first inner electrode patterns 221 having a strip shape can be arranged on the ceramic green sheet 211 at predetermined intervals. The plurality of first inner electrode patterns 221 having a strip shape can be arranged parallel to each other.

[0115] Ceramic green sheet 211 can be formed using a ceramic paste containing ceramic powder, organic solvent and organic binder.

[0116] The ceramic powder used as a material with a high dielectric constant can be a barium titanate (BaTiO3) based material, a lead-based perovskite composite material, a strontium titanate (SrTiO3) based material, etc., and barium titanate (BaTiO3) powder is preferred, but not limited to these. When sintering the ceramic green sheet 211, the ceramic green sheet 211 can become the dielectric layer 111 constituting the ceramic body 110.

[0117] The first internal electrode pattern 221 having a strip shape can be formed using an internal electrode paste containing a conductive metal. The conductive metal can be nickel (Ni), copper (Cu), palladium (Pd), or alloys thereof, but is not limited thereto.

[0118] The method of forming a first internal electrode pattern 221 with a strip shape on the ceramic green sheet 211 is not specifically limited, but can be a printing method such as screen printing or gravure printing.

[0119] Furthermore, although not shown, a plurality of second inner electrode patterns 222 having a strip shape may be provided at predetermined intervals on another ceramic green sheet 211.

[0120] In the following text, the ceramic green sheet with the first inner electrode pattern 221 thereon may be referred to as the first ceramic green sheet, and the ceramic green sheet with the second inner electrode pattern 222 thereon may be referred to as the second ceramic green sheet.

[0121] Next, as Figure 6B As shown, the first ceramic green sheet and the second ceramic green sheet can be stacked alternately such that a first inner electrode pattern 221 having a strip shape and a second inner electrode pattern 222 having a strip shape are stacked alternately.

[0122] Subsequently, the first inner electrode pattern 221 with a strip shape can become the first inner electrode 121, and the second inner electrode pattern 222 with a strip shape can become the second inner electrode 122.

[0123] According to another exemplary embodiment of this disclosure, the thickness td′ of each of the first ceramic green sheet and the second ceramic green sheet may be 0.6 μm or less, and the thickness te of each of the first inner electrode pattern and the second inner electrode pattern may be 0.5 μm or less.

[0124] Since this disclosure provides a micro-sized and high-capacitance multilayer ceramic capacitor in which the dielectric layer and the inner electrode are formed using a thin film having a thickness of 0.4 μm or less, the thickness td′ of each of the first ceramic green sheet and the second ceramic green sheet can be 0.6 μm or less, and the thickness te of each of the first inner electrode pattern and the second inner electrode pattern can be 0.5 μm or less.

[0125] Figure 6CThis is a cross-sectional view of a ceramic green sheet multilayer 220 in which a first ceramic green sheet and a second ceramic green sheet are stacked, according to another exemplary embodiment of this disclosure. Figure 6D This is a perspective view showing a multilayer of ceramic green sheets 220 in which first and second ceramic green sheets are stacked.

[0126] Reference Figure 6C and Figure 6D A first ceramic green sheet having a plurality of first inner electrode patterns 221 printed on it in parallel and strip-shaped manner and a second ceramic green sheet having a plurality of second inner electrode patterns 222 printed on it in parallel and strip-shaped manner can be alternately stacked.

[0127] More specifically, the first ceramic green sheet and the second ceramic green sheet can be stacked such that the central portion of the first inner electrode pattern 221 with a strip shape printed on the first ceramic green sheet overlaps the spacing between the second inner electrode pattern 222 with a strip shape printed on the second ceramic green sheet.

[0128] Next, as Figure 6D As shown, the ceramic green sheet multilayer body 220 can be cut through a plurality of first inner electrode patterns 221 having a strip shape and a plurality of second inner electrode patterns 222 having a strip shape. That is, the ceramic green sheet multilayer body 220 can be cut into multilayer bodies 210 along mutually orthogonal cutting lines C1-C1 and C2-C2.

[0129] More specifically, the first inner electrode pattern 221 and the second inner electrode pattern 222, both having a strip shape, can be cut along the length direction (i.e., along the cutting line C1-C1) into a plurality of inner electrodes with predetermined widths. In this case, the stacked ceramic green sheet can be cut together with the inner electrode patterns. Therefore, the dielectric layer can be formed to have the same width as the inner electrodes.

[0130] Furthermore, a multilayer ceramic green sheet can be cut along the cutting line C2-C2 at the size of a single ceramic body. That is, before forming the first side edge portion and the second side edge portion, a multilayer body 210 can be formed by cutting a stacked body with a rod shape along the cutting line C2-C2 at the size of a single ceramic body.

[0131] In other words, the stacked body with a rod-shaped form can be cut such that the central portion of the first inner electrode stacked on top of each other and the predetermined interval between the second inner electrode are cut with the same cutting line. Therefore, one end of the first inner electrode and the second inner electrode can be alternately exposed to the cutting surface.

[0132] Subsequently, the first side edge portion and the second side edge portion can be respectively disposed on the first side surface and the second side surface of the multilayer body 210.

[0133] Next, as Figure 6E As shown, a first side edge portion 212 and a second side edge portion (not shown) may be provided on the first side surface and the second side surface of the multilayer body 210, respectively.

[0134] In detail, in the method of forming the first side edge 212, a ceramic green sheet 212 coated with an adhesive (not shown) for the side surface can be provided on a stamping elastic material 300 formed of rubber.

[0135] Next, the multilayer body 210 can be rotated 90° so that the first side surface of the multilayer body 210 faces the ceramic green sheet 212 for the side surface coated with adhesive (not shown). Then, the multilayer body 210 can be pressed and the multilayer body 210 can be tightly bonded to the ceramic green sheet 212 for the side surface coated with adhesive (not shown).

[0136] When the ceramic green sheet 212 for the side surface is transferred to the multilayer body 210 by pressing the multilayer body 210 and bonding it tightly to the multilayer body 210 with an adhesive (not shown), the ceramic green sheet 212 for the side surface can be formed up to the edge portion of the side surface of the multilayer body 210 by utilizing the stamping elastic material 300 formed of rubber, and the remaining portion of the ceramic green sheet 212 can be cut off.

[0137] Figure 6F The ceramic green sheet 212 for the side surface is shown forming up to the edge portion of the side surface of the multilayer body 210.

[0138] Then, the multi-layer body 210 can be rotated, and a second side edge portion can be provided on the second side surface of the multi-layer body 210.

[0139] Next, a multilayer body 210 having a first side edge portion and a second side edge portion respectively disposed on its opposite side surfaces is calcined and sintered to form a ceramic body including a dielectric layer and a first inner electrode and a second inner electrode.

[0140] Unlike the prior art, according to another exemplary embodiment of this disclosure, an adhesive is applied to a ceramic green sheet 212 for the side surface, thereby enabling the ceramic green sheet 212 for the side surface to be transferred to the side surface of the multilayer body 210 under low temperature and low pressure conditions.

[0141] Therefore, damage to the multilayer body 210 can be significantly reduced, thus preventing the deterioration of the electrical characteristics of the multilayer ceramic capacitor after sintering and improving the reliability of the multilayer ceramic capacitor.

[0142] In addition, the ceramic green sheet 212 coated with adhesive for the side surface can be transferred to the side surface of the multilayer body 210 and pressed in the sintering process to improve the tight adhesion between the multilayer body and the ceramic green sheet for the side surface.

[0143] Then, external electrodes can be disposed on the third side surface exposed by the first inner electrode of the ceramic body and the fourth side surface exposed by the second inner electrode of the ceramic body, respectively.

[0144] According to another exemplary embodiment of this disclosure, the thickness of the ceramic green sheet for the side surface can be small, and the deviation in the thickness of the ceramic green sheet for the side surface can be small, thereby ensuring a large size of the capacitor forming portion.

[0145] In detail, since the average thickness of each of the first side edge portion 112 and the second side edge portion 113 after sintering can be greater than or equal to 2 μm and less than or equal to 10 μm, and the thickness deviation of each of the first side edge portion 112 and the second side edge portion 113 at each position can be small, large-size capacitor forming portions can be ensured.

[0146] Therefore, high-capacitance multilayer ceramic capacitors can be realized.

[0147] To avoid repetition, descriptions of features identical to those in the exemplary embodiments of this disclosure described above will be omitted.

[0148] The present disclosure will be described in more detail below with reference to experimental examples. However, the experimental examples are provided only to aid in a detailed understanding of the present disclosure, and the scope of the disclosure is not limited to the experimental examples.

[0149] Experimental Example

[0150] The multilayer ceramic capacitor according to the invention example is manufactured such that a metal or metal oxide 21 is disposed in a first side edge portion 112 and a second side edge portion 113, and the ratio of the diameter D of the metal or metal oxide 21 to the thickness td of the dielectric layer 111 is 0.8 or less, and the multilayer ceramic capacitor according to the comparative example is manufactured by a method according to the prior art.

[0151] Furthermore, as in the comparative example and the inventive example, a multilayer ceramic capacitor green sheet is formed by attaching a ceramic green sheet for the side surface to the electrode exposed portion of a multilayer ceramic green sheet body that has no edge due to the exposure of the inner electrode in the width direction to form a side edge portion.

[0152] By applying a predetermined temperature and pressure under conditions that significantly suppress the deformation of the sheet, a ceramic green sheet for the side surface is attached to the opposite side surface of a ceramic green sheet multilayer body, thereby manufacturing a multilayer ceramic capacitor green sheet with dimensions of 0603 (length × width × height of 0.6mm × 0.3mm × 0.3mm).

[0153] The multilayer ceramic capacitor samples manufactured as described above were subjected to a calcination process at 400°C or lower under a nitrogen atmosphere, and then sintered at a sintering temperature of 1200°C or lower and a hydrogen concentration of 0.5% H2 or lower. The electrical characteristics of the multilayer ceramic capacitor samples, such as short-circuit properties, were then generally confirmed.

[0154] As the measurement results of the above experiment confirm, the defect rate, such as short circuits, is high in the comparative example.

[0155] On the other hand, it can be confirmed that in the inventive example where the metal or metal oxide 21 is provided in each of the first side edge portion 112 and the second side edge portion 113 and the ratio of the diameter D of the metal or metal oxide 21 to the thickness td of the dielectric layer 111 is 0.8 or less, the defect rate is less than 5%, which makes the reliability excellent.

[0156] As described above, according to exemplary embodiments of the present disclosure, the size of metal particles or metal oxides (e.g., nickel particles or nickel oxides) disposed in the side edge portion of the side surface of the ceramic body can be controlled to prevent electric field concentration between the internal electrodes, thereby reducing short circuits.

[0157] While exemplary embodiments have been shown and described above, it will be apparent to those skilled in the art that variations and changes may be made without departing from the scope of the invention as defined by the appended claims.

Claims

1. A multilayer ceramic capacitor, the multilayer ceramic capacitor comprising: A ceramic body includes a dielectric layer and has a first surface and a second surface opposite to each other, a third surface and a fourth surface opposite to each other and connecting the first surface and the second surface to each other, and a fifth surface and a sixth surface opposite to each other and connected to the first surface to the fourth surface; Multiple internal electrodes are disposed in the ceramic body, all of which are exposed to the first surface and the second surface, and each has one end exposed to the third surface or the fourth surface; as well as The first side edge portion and the second side edge portion are respectively disposed on the first surface and the second surface of the ceramic body. Wherein, a metal or metal oxide is disposed in each of the first side edge portion and the second side edge portion, and the ratio of the diameter of the metal or metal oxide to the thickness of each of the dielectric layers is 0.8 or less, and The metal is nickel, and the metal oxide is an oxide containing nickel and magnesium.

2. The multilayer ceramic capacitor according to claim 1, wherein, The metal or the metal oxide is disposed in the regions of the first side edge and the second side edge adjacent to the dielectric layer.

3. The multilayer ceramic capacitor according to claim 1, wherein, The ratio of the thickness of the region of the first or second side edge that contacts the end of the outermost inner electrode among the plurality of inner electrodes to the thickness of the region of the first or second side edge that contacts the end of the inner electrode of the central layer among the plurality of inner electrodes is in the range of 0.9 to 1.

0.

4. The multilayer ceramic capacitor according to claim 1, wherein, The ratio of the thickness of the area of ​​the first or second side edge portion that contacts the edge of the ceramic body to the thickness of the area of ​​the first or second side edge portion that contacts the end of the inner electrode of the central layer of the plurality of inner electrodes is in the range of 0.9 to 1.

0.

5. The multilayer ceramic capacitor according to claim 1, wherein, The thickness of each of the dielectric layers is 0.4 μm or less, and the thickness of each inner electrode is 0.4 μm or less.

6. The multilayer ceramic capacitor according to claim 1, wherein, The average thickness of each of the first side edge portion and the second side edge portion is in the range of 2 μm to 10 μm.

7. The multilayer ceramic capacitor according to claim 1, wherein, The ceramic body includes an effective portion and a cover portion. In the effective portion, a capacitor is formed by including a plurality of internal electrodes disposed facing each other, with a dielectric layer between the plurality of internal electrodes. The cover portion is respectively disposed on the upper and lower surfaces of the effective portion. The thickness of each of the coverings is 20 μm or less.

8. A method for manufacturing a multilayer ceramic capacitor, the method comprising: A first ceramic green sheet and a second ceramic green sheet are prepared. A plurality of first internal electrode patterns are arranged on the first ceramic green sheet at predetermined intervals, and a plurality of second internal electrode patterns are arranged on the second ceramic green sheet at predetermined intervals. A ceramic green sheet multilayer body is formed by stacking the first ceramic green sheet and the second ceramic green sheet, wherein the first inner electrode pattern and the second inner electrode pattern alternate with each other; Cut the ceramic green sheet multilayer to have side surfaces that expose the ends of the first inner electrode pattern and the second inner electrode pattern in the width direction; A first side edge and a second side edge are respectively formed on the side surfaces that expose the ends of the first inner electrode pattern and the second inner electrode pattern; and A ceramic body comprising a dielectric layer and an internal electrode is prepared by sintering and cutting the aforementioned ceramic green sheet multilayer. In this embodiment, a metal or metal oxide is disposed in each of the first and second side edge portions, wherein the ratio of the diameter of the metal or metal oxide to the thickness of each of the dielectric layers is 0.8 or less, and The metal is nickel, and the metal oxide is an oxide containing nickel and magnesium.

9. The method according to claim 8, wherein, The metal or the metal oxide is disposed in the regions of the first side edge and the second side edge adjacent to the dielectric layer.

10. The method according to claim 8, wherein, The thickness of each of the first ceramic green sheet and the second ceramic green sheet is 0.6 μm or less, and the thickness of each of the first inner electrode pattern and the second inner electrode pattern is 0.5 μm or less.

11. The method according to claim 8, wherein, The ratio of the thickness of the region of the first or second side edge that contacts the end of the outermost inner electrode in the inner electrode to the thickness of the region of the first or second side edge that contacts the end of the inner electrode in the central layer of the inner electrode is in the range of 0.9 to 1.

0.

12. The method according to claim 8, wherein, The ratio of the thickness of the area of ​​the first or second side edge portion that contacts the edge of the ceramic body to the thickness of the area of ​​the first or second side edge portion that contacts the end of the inner electrode of the central layer in the inner electrode is in the range of 0.9 to 1.

0.

13. The method according to claim 8, wherein, The average thickness of each of the first and second side edge portions after sintering is in the range of 2 μm to 10 μm.

14. The method according to claim 8, wherein, The ceramic body includes an effective portion and a cover portion. In the effective portion, a capacitor is formed by including internal electrodes disposed facing each other and a dielectric layer between the internal electrodes. The cover portion is respectively disposed on the upper and lower surfaces of the effective portion. The thickness of each of the coverings is 20 μm or less.

15. The method according to claim 8, wherein, The thickness of each of the dielectric layers is 0.4 μm or less, and the thickness of each inner electrode is 0.4 μm or less.

16. A multilayer ceramic capacitor, the multilayer ceramic capacitor comprising: A ceramic body, including a dielectric layer, having a first surface and a second surface opposite to each other, a third surface and a fourth surface opposite to each other and connecting the first surface and the second surface to each other, and a fifth surface and a sixth surface opposite to each other and connected to the first surface to the fourth surface; Multiple internal electrodes are disposed in the ceramic body, all of which are exposed to the first surface and the second surface, and each has one end exposed to the third surface or the fourth surface; as well as The first side edge portion and the second side edge portion are respectively disposed on the first surface and the second surface of the ceramic body. Wherein, a metal or metal oxide is disposed in each of the first side edge portion and the second side edge portion, and the diameter of the metal or metal oxide is smaller than the thickness of each of the dielectric layers, and The metal is nickel, and the metal oxide is an oxide containing nickel and magnesium.

17. The multilayer ceramic capacitor according to claim 16, wherein, The ratio of the diameter of the metal or the metal oxide to the thickness of each of the dielectric layers is 0.8 or less, and The internal electrode contains nickel.

18. The multilayer ceramic capacitor according to claim 16, wherein, The thickness of each of the dielectric layers is 0.4 μm or less, and the thickness of each inner electrode is 0.4 μm or less.

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