Multilayer Ceramic Capacitors

Abstract

A multilayer ceramic capacitor is provided. The multilayer ceramic capacitor comprises: a ceramic body, comprising a dielectric layer and a first inner electrode and a second inner electrode; and a first outer electrode and a second outer electrode, which are arranged on the outer surface of the ceramic body, wherein the dielectric layer comprises dielectric grains containing a dielectric ceramic composition, the dielectric ceramic composition comprises a main component of a matrix material and a subsidiary component, the subsidiary component comprises Dy and Nb as a first subsidiary component, and the main component of the matrix material comprises at least one compound selected from the following compounds: BaTiO3; (Ba 1‑x Ca x )(Ti 1‑ y Ca y )O3, where 0≤x≤0.3, 0≤y≤0.1; (Ba 1‑x Ca x )(Ti 1‑y Zr y )O3, where 0≤x≤0.3, 0≤y≤0.5; and Ba(Ti 1‑y Zr y )O3, where 0

Description

[0001] This application is a divisional application of the invention patent application "Dielectric ceramic composition and multilayer ceramic capacitor comprising the same" with application date of December 16, 2019 and application number 201911290054.5. Technical Field

[0002] The present disclosure relates to a dielectric ceramic composition having improved reliability and a multilayer ceramic capacitor including the same. Background Art

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

[0004] As there has been a recent trend toward miniaturization and multifunctionalization of electronic products and chip components, there has been a need for a multilayer ceramic capacitor that is smaller in size but has greater capacitance.

[0005] A method for miniaturizing a multilayer ceramic capacitor while increasing its capacitance is to reduce the thickness of the dielectric layer and the internal electrode layer to stack a greater number of layers. Currently, the thickness of the dielectric layer is about 0.6 μm, and efforts have been made to develop thinner dielectric layers.

[0006] Under such circumstances, ensuring the reliability of the dielectric layer is becoming a major issue for dielectric materials. In addition, as the degradation of the insulation resistance of the dielectric material increases, difficulties in managing quality and yield are becoming a problem.

[0007] In order to solve such a problem, it is necessary to develop a new method for ensuring high reliability not only for the structure of the multilayer ceramic capacitor but also for the composition of the dielectric.

[0008] When a dielectric composition capable of improving current reliability is secured, thinner multilayer ceramic capacitors can be manufactured. Summary of the invention

[0009] An aspect of the present disclosure is to provide a dielectric ceramic composition having improved reliability and a multilayer ceramic capacitor including the same.

[0010] According to another aspect of the present disclosure, a dielectric ceramic composition includes a main component and a subsidiary component of a barium titanate (BaTiO3)-based matrix material, wherein the subsidiary component includes dysprosium (Dy) and niobium (Nb) as a first subsidiary component. The total content of titanium (Ti), Dy and Nb based on 100 mol of the main component of the barium titanate (BaTiO3)-based matrix material is less than or equal to 1.5 mol, and the content of Dy based on 100 mol of Ti of the main component of the barium titanate (BaTiO3)-based matrix material satisfies 0.7 mol<Dy<1.1 mol.

[0011] According to one aspect of the present disclosure, a multilayer ceramic capacitor includes: a ceramic body including a dielectric layer and a first inner electrode and a second inner electrode, the first inner electrode and the second inner electrode are arranged to face each other with each dielectric layer interposed between the first inner electrode and the second inner electrode; and a first outer electrode and a second outer electrode are arranged on the outer surface of the ceramic body, wherein the first outer electrode is electrically connected to the first inner electrode and the second outer electrode is electrically connected to the second inner electrode. The dielectric layer includes dielectric grains containing a dielectric ceramic composition, and the dielectric ceramic composition includes a BaTiO3-based matrix material main component and a subcomponent, wherein the subcomponent includes Dy and Nb as a first subcomponent. The total content of Dy and Nb based on 100 mol of titanium (Ti) of the BaTiO3-based matrix material main component is less than or equal to 1.5 mol, and the content of Dy based on 100 mol of Ti of the BaTiO3-based matrix material main component satisfies 0.7 mol<Dy<1.1 mol. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The above and other aspects, features and advantages of the present disclosure will be more clearly understood through the following detailed description taken in conjunction with the accompanying drawings, in which:

[0013] Figure 1 is a schematic perspective view of a multilayer ceramic capacitor according to an embodiment of the present disclosure;

[0014] Figure 2 It is along Figure 1 A cross-sectional view taken along line II′ in FIG.

[0015] FIG. 3A to FIG. 3C is a graph of highly accelerated life test (HALT) test results of an example embodiment of the present disclosure and a comparative example; and

[0016] FIG. 4A to FIG. 4C is a graph showing HALT test results of an example according to an embodiment of the present disclosure and a comparative example. DETAILED DESCRIPTION

[0017] Hereinafter, embodiments of the present disclosure will be described as follows with reference to the accompanying drawings. However, the present disclosure may be presented in many different forms and should not be construed as being limited to the embodiments set forth herein. More specifically, these embodiments are provided so that the present disclosure will be thorough and complete, and the scope of the present disclosure will be fully communicated to those skilled in the art. In the accompanying drawings, for the sake of clarity, the shapes and sizes of the elements may be exaggerated, and the same reference numerals will always be used to indicate the same or similar elements.

[0018] Figure 1 is a schematic perspective view of a multilayer ceramic capacitor according to an embodiment of the present disclosure.

[0019] Figure 2 It is along Figure 1 A cross-sectional view taken along line II′ in FIG.

[0020] Reference Figure 1 and Figure 2 The multilayer ceramic capacitor 100 according to the embodiment includes: a ceramic body 110 including a dielectric layer 111 and first and second internal electrodes 121 and 122 disposed to face each other with each dielectric layer interposed therebetween; and first and second external electrodes 131 and 132 disposed on outer surfaces of the ceramic body 110. The first external electrode 131 is electrically connected to the first internal electrode 121, and the second external electrode 132 is electrically connected to the second internal electrode 122.

[0021] Regarding the multilayer ceramic capacitor 100 according to the embodiment, Figure 1 The “length direction”, “width direction” and “thickness direction” of the dielectric layer are defined as the “L” direction, the “W” direction and the “T” direction, respectively. The “thickness direction” may be used in the same meaning as the direction along which the dielectric layers are stacked (e.g., the “stacking direction”).

[0022] Although not particularly limited, the configuration of the ceramic body 110 may be a rectangular cuboid shape as shown in the drawings.

[0023] The plurality of internal electrodes 121 and 122 formed inside the ceramic body 110 have one end exposed to one surface of the ceramic body 110 or the other surface of the ceramic body 110 disposed opposite to the one surface.

[0024] The internal electrodes 121 and 122 may include a pair of first and second internal electrodes 121 and 122 having different polarities.

[0025] One end of the first internal electrode 121 may be exposed to one surface of the ceramic body, and one end of the second internal electrode 122 may be exposed to the other surface of the ceramic body disposed opposite to the one surface.

[0026] The first and second external electrodes 131 and 132 are respectively formed on one surface of the ceramic body 110 and the other surface of the ceramic body 110 disposed opposite to the one surface to be electrically connected to the internal electrodes.

[0027] The material of the first and second internal electrodes 121 and 122 is not particularly limited and may be a conductive paste including at least one element selected from the group consisting of, for example, silver (Ag), lead (Pb), platinum (Pt), nickel (Ni), and copper (Cu).

[0028] The first and second external electrodes 131 and 132 may be electrically connected to the first and second internal electrodes 121 and 122, respectively, to generate capacitance. The second external electrode 132 may be connected to a potential different from that connected to the first external electrode 131.

[0029] The conductive material included in the first and second external electrodes 131 and 132 is not particularly limited, but may include at least one element selected from the group consisting of nickel (Ni), copper (Cu), and alloys thereof.

[0030] The thickness of the first and second external electrodes 131 and 132 may be appropriately determined according to their uses, etc., and is not particularly limited, but may be, for example, 10 μm to 50 μm.

[0031] According to an embodiment, the material forming the dielectric layer 111 is not particularly limited as long as sufficient capacitance can be obtained using the material, and may be, for example, barium titanate (BaTiO 3 ) powder.

[0032] The material forming the dielectric layer 111 may include various additives added to BaTiO 3 powder or the like, an organic solvent, a plasticizer, a binder, a dispersant, and the like.

[0033] The dielectric layers 111 in a sintered state may be integrated into a single body such that boundaries between adjacent dielectric layers 111 may not be apparent.

[0034] The first and second internal electrodes 121 and 122 may be formed on the dielectric layer 111 , and the internal electrodes 121 and 122 may be formed inside the ceramic body 110 by sintering while having a dielectric layer therebetween.

[0035] The thickness of the dielectric layer 111 can be selectively changed according to the capacitance design of the capacitor. In an embodiment, the thickness of the dielectric layer after sintering can be 0.4 μm or less per layer.

[0036] In addition, the thickness of the first internal electrode 121 and the thickness of the second internal electrode 122 after sintering may be 0.4 μm or less per layer.

[0037] According to an embodiment, the dielectric layer 111 includes dielectric grains including a dielectric ceramic composition, and the dielectric ceramic composition includes a BaTiO3-based matrix material main component (matrix material main component) and a subcomponent, wherein the subcomponent includes dysprosium (Dy) and niobium (Nb) as a first subcomponent. Based on 100 mol of titanium (Ti) as the matrix material main component, the total content of Dy and Nb is less than or equal to 1.5 mol, and based on 100 mol of Ti as the matrix material main component, the content of Dy satisfies 0.7 mol<Dy<1.1 mol.

[0038] In contrast, a lot of rare earth elements are generally added to the dielectric layer 111 to ensure the reliability of the dielectric inside the multilayer ceramic capacitor.

[0039] When dysprosium (Dy) is added to BaTiO3, which is the main component of the base material, Dy among such rare earth elements reduces the oxygen vacancy concentration and replaces the barium (Ba) site. Therefore, it is known that Dy has the effect of improving reliability.

[0040] On the other hand, when a rare earth element having an ion radius larger than that of Dy (e.g., lanthanum (La), samarium (Sm), etc.) is added to the dielectric ceramic composition, the oxygen vacancy concentration is more effectively reduced because the Ba site can be more effectively substituted. However, in this case, since the insulation resistance is rapidly reduced due to excessive semiconductorization, the rare earth element may not be practically used.

[0041] Therefore, it is considered that a new rare earth element may be added to a dielectric ceramic composition to ensure insulation resistance while minimizing the oxygen vacancy concentration to improve reliability.

[0042] In an embodiment, an optimal content ratio of rare earth elements may be determined to ensure excellent reliability by including Nb in addition to Dy in a dielectric ceramic composition, which shows stable dielectric characteristics.

[0043] According to an embodiment, the dielectric ceramic composition includes a BaTiO3-based matrix material main component (matrix material main component) and a subcomponent. The subcomponent includes Dy and Nb as first subcomponents. In this case, the total content of Dy and Nb in the dielectric ceramic composition is less than or equal to 1.5 mol based on 100 mol of Ti, which is the matrix material main component.

[0044] Reliability (such as insulation resistance) can be improved by adjusting the total content of Dy and Nb in the dielectric ceramic composition to be less than or equal to 1.5 mol based on 100 mol of Ti which is the main component of the base material.

[0045] Regarding reliability improvement, it is more advantageous when the total content of Dy and Nb in the dielectric ceramic composition increases; however, when Dy and Nb are present in a specific amount or more, they become semi-conductive, deteriorating the properties of the insulator and the sinterability. Therefore, based on 100 mol of Ti as the main component of the base material, the total content of Dy and Nb in the dielectric ceramic composition can be less than or equal to 1.5 mol.

[0046] In other words, when the total content of Dy and Nb in the dielectric ceramic composition exceeds 1.5 mol (based on 100 mol of Ti as the main component of the base material), insufficient sinterability caused by an excessive content of rare earth elements may lead to problems such as capacitance shortage and reliability deterioration.

[0047] Furthermore, according to the embodiment, based on 100 mol of Ti as the main component of the base material, the total content of Dy and Nb in the dielectric ceramic composition can be greater than 0.2 mol.

[0048] When the total content of Dy and Nb in the dielectric ceramic composition is less than or equal to 0.2 mol (based on 100 mol of Ti as the main component of the base material), the total content of the rare earth elements Dy and Nb is too small, and thus the reliability improvement effect is not significant.

[0049] Therefore, in the embodiment, based on 100 mol of Ti as the main component of the base material, it is preferable that the total content of Dy and Nb in the dielectric ceramic composition exceeds 0.2 mol.

[0050] In addition, according to the embodiment, based on 100 mol of Ti as the main component of the base material, the content of Dy in the dielectric ceramic composition satisfies 0.7 mol < Dy < 1.1 mol.

[0051] When the content of Dy in the dielectric ceramic composition satisfies 0.7 mol < Dy < 1.1 mol (based on 100 mol of Ti as the main component of the base material), the reliability improvement effect (such as improvement of insulation resistance) can be excellent.

[0052] When the content of Dy in the dielectric ceramic composition is less than or equal to 0.7 mol (based on 100 mol of Ti as the main component of the base material), the content of Dy is too small, and thus there may be problems regarding reliability (such as reduction of insulation resistance).

[0053] On the other hand, when the content of Dy in the dielectric ceramic composition is greater than or equal to 1.1 mol (based on 100 mol of Ti as the main component of the base material), it causes a relatively small content of Nb, which may lead to problems regarding reliability (such as reduction of insulation resistance).

[0054] According to the embodiment, regarding the dielectric ceramic composition included in the dielectric layer in the ceramic body, by including rare earth elements Dy and Nb as subcomponents in the dielectric ceramic composition while controlling the contents of Dy and Nb, high dielectric characteristics can be obtained and reliability such as insulation resistance can be improved.

[0055] According to an embodiment, Nb may be disposed at the boundaries of dielectric grains.

[0056] Nb disposed at the boundaries of dielectric grains can suppress a decrease in insulation resistance of the multilayer ceramic capacitor, thereby improving reliability.

[0057] The multilayer ceramic capacitor 100 according to the embodiment is a miniaturized product with high capacitance and includes a dielectric layer 111 having a thickness of less than or equal to 0.4 μm and first and second internal electrodes 121 and 122 having a thickness of less than or equal to 0.4 μm, but the thickness is not particularly limited thereto. The thickness of the dielectric layer 111 is greater than 0.0 μm.

[0058] In addition, the size of the multilayer ceramic capacitor 100 may be 1005 (length×width, 1.0 mm×0.5 mm) or less.

[0059] For example, since the multilayer ceramic capacitor 100 according to the embodiment is a miniaturized product with high capacitance, the thickness of the dielectric layer 111 and the first and second internal electrodes 121 and 122 are thinner than those of the prior art product. For such a product to which a thin film dielectric layer and internal electrodes are applied, research for improving reliability such as insulation resistance is a very important issue.

[0060] In detail, since the related art multilayer ceramic capacitor has relatively thicker dielectric layers and inner electrodes than the multilayer ceramic capacitor according to the embodiment, reliability is not a big problem even if the components of the dielectric ceramic composition are the same as those of the related art.

[0061] However, for products of multilayer ceramic capacitors to which thin film dielectric layers and internal electrodes are applied as in the embodiments of the present disclosure, reliability of the multilayer ceramic capacitor is important, and it is necessary to adjust the components of the dielectric ceramic composition.

[0062] For example, in an embodiment, even when the dielectric layer 111 is a thin film having a thickness less than or equal to 0.4 μm, the reliability (such as insulation resistance) can be improved by including Dy and Nb as the first sub-components in the dielectric ceramic composition for the dielectric layer 111, and adjusting the total content of Dy and Nb to be less than or equal to 1.5 mol (based on 100 mol of Ti as the main component of the matrix material), and adjusting the content of Dy in the dielectric ceramic composition to satisfy 0.7 mol < Dy < 1.1 mol (based on 100 mol of Ti as the main component of the matrix material).

[0063] However, in this case, the thin film does not mean that the thicknesses of the dielectric layer 111 and the internal electrodes 121 and 122 are less than or equal to 0.4 μm, but can be understood as meaning that the dielectric layer and the internal electrodes are thinner than those of the prior art products.

[0064] Hereinafter, each component of the dielectric ceramic composition according to the embodiment will be described in more detail.

[0065] a) Main component of the matrix material

[0066] The dielectric ceramic composition according to the embodiment may include a main component of the matrix material represented by BaTiO3.

[0067] According to an embodiment of the present disclosure, the main component of the matrix material includes at least one compound selected from the group consisting of BaTiO3, (Ba 1-x Ca x )(Ti 1-y Ca y )O3 (where 0 ≤ x ≤ 0.3, 0 ≤ y ≤ 0.1), (Ba 1-x Ca x )(Ti 1-y Zr y )O3 (where 0 ≤ x ≤ 0.3, 0 ≤ y ≤ 0.5), and Ba(Ti 1-y Zr y )O3 (where 0 < y ≤ 0.5), but is not necessarily limited thereto.

[0068] The dielectric ceramic composition according to the embodiment may have a room temperature dielectric constant of 2000 or more.

[0069] The main component of the matrix material is not particularly limited, but the average diameter of the main component powder may be greater than or equal to 40 nm and less than or equal to 200 nm.

[0070] b) First sub-component

[0071] According to an embodiment of the present disclosure, the dielectric ceramic composition includes Dy and Nb as elements of the first sub-component.

[0072] In the embodiment, the first subcomponent is used to suppress reliability degradation of a multilayer ceramic capacitor to which the dielectric ceramic composition is applied.

[0073] According to an embodiment, even when the thickness of the dielectric layer 111 is less than or equal to 0.4 μm, reliability (such as insulation resistance) can be improved by including Dy and Nb as the first subcomponents, and adjusting the total content of Dy and Nb to be less than or equal to 1.5 mol (based on 100 mol of Ti, the main component of the base material) and adjusting the Dy content to satisfy 0.7 mol<Dy<1.1 mol (based on 100 mol of Ti, the main component of the base material).

[0074] Specifically, the total content of Dy and Nb in the dielectric ceramic composition may be greater than 0.2 mol based on 100 mol of Ti which is a main component of the base material.

[0075] When the total content of Dy and Nb in the dielectric ceramic composition is less than or equal to 0.2 mol based on 100 mol of Ti which is the main component of the base material, the total content of Dy and Nb as rare earth elements is too small and thus the reliability improvement effect is not significant.

[0076] Therefore, in an embodiment, based on 100 mol of Ti, which is the main component of the matrix material, the total content of Dy and Nb in the dielectric ceramic composition is preferably greater than 0.2 mol. The total content of Dy and Nb disclosed in the present invention may be the total content of Dy and Nb contained in the dielectric layer 111. The Dy content disclosed in the present invention may be the Dy content contained in the dielectric layer 111. The Dy content disclosed in the present invention may also be represented by the atomic percentage (at.%) of Dy in the dielectric ceramic composition (based on 100 at.% of Ti, which is the main component of the matrix material in the dielectric ceramic composition). The Nb content disclosed in the present invention may be the Nb content contained in the dielectric layer 111. The Nb content disclosed in the present invention may also be represented by the atomic percentage (at.%) of Nb in the dielectric ceramic composition (based on 100 at.% of Ti, which is the main component of the matrix material in the dielectric ceramic composition).

[0077] c) Second subcomponent

[0078] According to an embodiment of the present disclosure, the dielectric ceramic composition may include one or more oxides and / or one or more carbonates as a second subcomponent, wherein the one or more oxides include at least one element selected from the group consisting of manganese (Mn), vanadium (V), chromium (Cr), iron (Fe), nickel (Ni), cobalt (Co), copper (Cu), and zinc (Zn), and the one or more carbonates include at least one element selected from the group consisting of Mn, V, Cr, Fe, Ni, Co, Cu, and Zn.

[0079] The total amount of the oxide containing at least one element selected from the group consisting of Mn, V, Cr, Fe, Ni, Co, Cu and Zn and the carbonate containing at least one element selected from the group consisting of Mn, V, Cr, Fe, Ni, Co, Cu and Zn as the second subcomponent can be 0.1 mol to 2.0 mol (both inclusive) (based on 100 mol of Ti which is the main component of the base material).

[0080] The second subcomponent is used to lower the firing temperature and enhance the high temperature withstand voltage characteristics of the multilayer ceramic capacitor to which the dielectric ceramic composition is applied.

[0081] The content of the second subcomponent, the third subcomponent, and the fourth subcomponent described in the present disclosure may be an amount contained in the present disclosure based on 100 mol of the base material powder, and may be defined as the number of moles of metal ions contained in each subcomponent. The content of the second subcomponent, the third subcomponent, and the fourth subcomponent of the present disclosure may be a content contained in the dielectric layer 111.

[0082] When the content of the second subcomponent is less than 0.1 mol, the firing temperature increases and the high-temperature withstand voltage characteristics slightly decrease.

[0083] When the content of the second subcomponent is greater than 2.0 mol, high-temperature withstand voltage and room-temperature resistivity may be deteriorated.

[0084] In detail, the dielectric ceramic composition according to the embodiment may include 0.1 mol to 2.0 mol (inclusive) of the second subcomponent based on 100 mol of Ti as the main component of the base material. This will enable firing at low temperature and provide high temperature withstand voltage characteristics.

[0085] d) The third subcomponent

[0086] According to an embodiment of the present disclosure, the dielectric ceramic composition may include a third subcomponent that is an oxide and / or a carbonate including a fixed-valence acceptor element magnesium (Mg).

[0087] The fixed valence acceptor element Mg may be contained as the third subcomponent in an amount of greater than or equal to 0.2 mol and less than 0.7 mol based on 100 mol of Ti which is a main component of the base material.

[0088] The third subcomponent as a fixed valence acceptor element or a compound containing a fixed valence acceptor element is used as an acceptor to reduce the electron concentration. The reliability improvement effect due to the n-type can be significantly improved by adding 0.2 mol or more and less than 0.7 mol (based on 100 mol of Ti, the main component of the base material) of the fixed valence acceptor element Mg as the third subcomponent.

[0089] When the content of the third subcomponent is greater than 0.7 mol based on 100 mol of Ti as the main component of the base material, the dielectric constant may decrease and the dielectric breakdown voltage (BDV) may decrease, which may be problematic.

[0090] In addition, in the embodiment, the fixed valence acceptor element Mg as the third subcomponent can have reduced insulation resistance due to the addition of Nb. In order to compensate for this, it is preferable to add Mg in a minimum content of 0.2 mol.

[0091] Table 1 below shows test results of the capacitance, dissipation factor (DF), and BDV of the chips of the prototype MLCCs according to the experimental examples (Embodiment Example 1 and Comparative Examples 1 and 2).

[0092] Each test was performed at two conditions, 1110°C and 1120°C.

[0093] The contents of Dy and Nb added to the dielectric ceramic compositions in Embodiment Example 1 and Comparative Examples 1 and 2 were 0.9 mol and 0.05 mol, respectively, based on 100 mol of Ti which was the main component of the base material.

[0094] In Embodiment Example 1, 0.467 mol of Mg was added based on 100 mol of Ti which was the main component of the base material, whereas in Comparative Examples 1 and 2, 0.7 mol and 0.93 mol of Mg were added based on 100 mol of Ti which was the main component of the base material, respectively.

[0095] [Table 1]

[0096]

[0097] Referring to Table 1 above, Comparative Examples 1 and 2, in which excessive amounts (i.e., 0.7 mol and 0.93 mol) of Mg were added based on 100 mol of Ti, the main component of the base material, showed reduced reliability due to low BDV. Specifically, in Comparative Example 2, a short circuit defect was generated due to low BDV.

[0098] In contrast, Example 1 of the embodiment of the present disclosure shows excellent reliability due to high BDV.

[0099] e) The fourth component

[0100] According to an embodiment of the present disclosure, the dielectric ceramic composition may include one or more oxides including at least one element of silicon (Si) and aluminum (Al) or a glass compound including Si as a fourth subcomponent.

[0101] The dielectric ceramic composition may further include a fourth subcomponent greater than 0.0 mol (e.g., greater than or equal to 0.001 mol) and less than or equal to 0.5 mol (based on 100 mol of Ti as a main component of the base material), the fourth subcomponent including one or more oxides including at least one element of Si and Al or a glass compound including Si.

[0102] The fourth subcomponent content may be the content of Si and Al elements contained in the dielectric ceramic composition as the fourth subcomponent regardless of the addition form such as glass, oxide, or carbonate.

[0103] The fourth subcomponent is used to lower the firing temperature and improve the high temperature withstand voltage characteristics of the multilayer ceramic capacitor to which the dielectric ceramic composition is applied.

[0104] When the fourth subcomponent content exceeds 0.5 mol based on 100 mol of Ti which is the main component of the base material, there may be problems such as reduction in sinterability and density, formation of a secondary phase, etc., which may be problematic.

[0105] In detail, according to the embodiment, when the dielectric ceramic composition includes less than or equal to 0.5 mol of Al, Al serves as an acceptor and reduces electron concentration, thereby improving reliability.

[0106] Hereinafter, the present disclosure will be described in more detail with reference to embodiments and comparative examples of the present disclosure. These embodiments and comparative examples are provided to help a comprehensive understanding of the present invention and should not be construed as being limited to the embodiments set forth herein.

[0107] (Example of Embodiment)

[0108] The dielectric layer is formed by adding additives (such as Dy, Nb, Al, Mg, Mn, etc.), a binder and an organic solvent (such as ethanol) to dielectric powder particles containing BaTiO3 as a main component of a matrix material, and wet-mixing them to prepare a dielectric slurry, and then spreading the dielectric slurry on a carrier film and drying it to prepare a ceramic green sheet.

[0109] All element additives are monodispersed in a size of 40% or less based on BaTiO3 and added.

[0110] In an embodiment example of the present disclosure, a multilayer ceramic capacitor is manufactured so that the total content of Dy and Nb in the dielectric slurry is less than or equal to 1.5 mol based on 100 mol of titanium (Ti), the main component of the base material; in detail, the Dy content satisfies 0.7 mol<Dy<1.1 mol based on 100 mol of Ti, the main component of the base material.

[0111] In Embodiment Example 1, the total content of Dy and Nb added to the dielectric slurry (ie, the total content of Dy and Nb in the dielectric ceramic composition) was 1.5 mol based on 100 mol of Ti which was the main component of the base material.

[0112] In Embodiment Example 2, the content of Dy added to the dielectric slurry (ie, the total content of Dy in the dielectric ceramic composition) was 0.9 mol based on 100 mol of Ti which was the main component of the base material.

[0113] The ceramic green sheet is manufactured into a sheet having a thickness of several micrometers by mixing ceramic powder, a binder, and a solvent to prepare slurry and using the slurry to perform a doctor blade method.

[0114] Then, a conductive paste for an internal electrode including 40 to 50 parts by weight of a nickel powder having an average particle size of 0.1 to 0.2 μm was prepared.

[0115] Conductive paste for internal electrodes is screen-printed on ceramic green sheets to form internal electrodes. Then, the green sheets on which the internal electrode patterns are formed are stacked to form a laminate, which is then pressed and cut.

[0116] Then, the cut laminated body is heated to remove the binder, and fired in a high-temperature reducing atmosphere to form a ceramic body.

[0117] During firing, heat treatment was performed by firing at 1100° C. to 1200° C. for 2 hours in a reducing atmosphere (0.1% H 2 / 99.9% N 2 , H 2 O / H 2 / N 2 ) and then oxidizing at 1000° C. for 3 hours in a nitrogen (N 2 ) atmosphere.

[0118] A termination process and electrode firing are performed on the fired ceramic body using a copper (Cu) paste, and external electrodes are formed.

[0119] In addition, after firing, the dielectric layer 111 and the first and second internal electrodes 121 and 122 inside the ceramic body 110 are manufactured to have a thickness less than or equal to 0.4 μm.

[0120] (Comparative Example 1)

[0121] In Comparative Example 1, the total content of Dy and Nb in the dielectric ceramic composition was 1.8 mol (exceeding 1.5 mol) based on 100 mol of Ti which was the main component of the base material. The remaining manufacturing process was the same as the previously described manufacturing process.

[0122] (Comparative Example 2)

[0123] In Comparative Example 2, the total content of Dy and Nb in the dielectric ceramic composition was 2.1 mol (exceeding 1.5 mol) based on 100 mol of Ti which was the main component of the base material. The remaining manufacturing process was the same as the previously described manufacturing process.

[0124] (Comparative Example 3)

[0125] In Comparative Example 3, 1.1 mol of Dy was added to the dielectric ceramic composition based on 100 mol of titanium (Ti) which is a main component of the base material. The remaining manufacturing process was the same as the previously described manufacturing process.

[0126] (Comparative Example 4)

[0127] In Comparative Example 4, 0.7 mol of Dy was added to the dielectric ceramic composition based on 100 mol of titanium (Ti) which is a main component of the base material. The remaining manufacturing process was the same as the previously described manufacturing process.

[0128] A HALT test was performed on samples of the prototype multilayer ceramic capacitors (prototype MLCCs) manufactured in Embodiment Examples 1 to 2 and Comparative Examples 1 to 4 as described above.

[0129] FIG. 3A to FIG. 3C is a graph showing HALT test results of an example according to an embodiment of the present disclosure and a comparative example.

[0130] Figure 3A The multilayer ceramic capacitor sample of Example 1 of the embodiment is shown, in which the total content of Ti, Dy and Nb based on 100 mol of the main component of the base material is 1.5 mol. The HALT test shows excellent reliability without defects.

[0131] In the case of Embodiment Example 1, the nominal capacitance was 101% and the BDV was 63 V, indicating excellent reliability in capacitance and BDV.

[0132] Figure 3B Comparative Example 1 is shown, in which the total content of Ti, Dy and Nb based on 100 mol of the main component of the base material is 1.8 mol (exceeding 1.5 mol), Figure 3C Comparative Example 2 is shown, in which the total content of Ti, Dy and Nb based on 100 mol of the main component of the base material is 2.1 mol (exceeding 1.5 mol).

[0133] In both cases of Comparative Example 1 and Comparative Example 2, several defects were observed in the HALT test, indicating reduced reliability.

[0134] Furthermore, in Comparative Example 1, the nominal capacitance was 90% and the BDV was 58 V, and in Comparative Example 2, the nominal capacitance was 82% and the BDV was 47 V, indicating that the reliability was unsatisfactory.

[0135] FIG. 4A to FIG. 4C is a graph showing HALT test results of an example according to an embodiment of the present disclosure and a comparative example.

[0136] Figure 4A Comparative Example 3 is shown, in which 1.1 mol of Dy was added based on 100 mol of titanium (Ti) which is a main component of the base material. Several defects were detected in the HALT test, indicating a decrease in reliability.

[0137] Figure 4B The embodiment example 2 is shown, in which 0.9 mol of Dy was added based on 100 mol of Ti which is the main component of the base material. No defects were detected in the HALT test, indicating excellent reliability.

[0138] Figure 4C Comparative Example 4 is shown, in which 0.7 mol of Dy was added based on 100 mol of Ti which was the main component of the base material. Several defects were detected in the HALT test, indicating a decrease in reliability.

[0139] According to an embodiment, a dielectric ceramic composition included in a dielectric layer in a ceramic body may have improved reliability such as improved insulation resistance by including new rare earth elements Nb and Dy as subcomponents while controlling the contents of Nb and Dy.

[0140] While example embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations may be made without departing from the scope of the present disclosure as defined by the appended claims.

Claims

1. A multilayer ceramic capacitor comprising: a ceramic body including a dielectric layer and first and second internal electrodes, the first and second internal electrodes being arranged to face each other with each dielectric layer interposed therebetween; and a first external electrode and a second external electrode disposed on an outer surface of the ceramic body, the first external electrode being electrically connected to the first internal electrode and the second external electrode being electrically connected to the second internal electrode, Wherein, the dielectric layer comprises dielectric grains containing a dielectric ceramic composition, The dielectric ceramic composition comprises a barium titanate-based matrix material as a main component and a subcomponent, wherein the subcomponent comprises Dy and Nb as a first subcomponent, Wherein, the total content of Ti, Dy and Nb based on 100 mol of the main components of the barium titanate-based matrix material is less than or equal to 1.5 mol, wherein the thickness of at least one of the dielectric layers is less than or equal to 0.4 μm, and Wherein, Nb is arranged at the boundary of the dielectric grains.

2. The multilayer ceramic capacitor according to claim 1, wherein: The content of Dy satisfies 0.7 mol<Dy<1.1 mol based on 100 mol of Ti which is a main component of the barium titanate-based matrix material.

3. The multilayer ceramic capacitor according to claim 2, wherein: The dielectric ceramic composition includes 0.1 mol or more and 2.0 mol or less of the second subcomponent based on 100 mol of Ti which is a main component of the barium titanate-based matrix material, The second subcomponent comprises one or more oxides and / or one or more carbonates, the one or more oxides comprising at least one element selected from the group consisting of Mn, V, Cr, Fe, Ni, Co, Cu and Zn, and the one or more carbonates comprising at least one element selected from the group consisting of Mn, V, Cr, Fe, Ni, Co, Cu and Zn.

4. The multilayer ceramic capacitor according to claim 3, wherein: The dielectric ceramic composition includes 0.2 mol or more and less than 0.7 mol of the third subcomponent based on 100 mol of Ti which is the main component of the barium titanate-based matrix material, The third subcomponent is an oxide or a carbonate containing a fixed-valence acceptor element Mg.

5. The multilayer ceramic capacitor according to claim 4, wherein: The dielectric ceramic composition includes 0.001 mol or more and 0.5 mol or less of the fourth subcomponent based on 100 mol of Ti which is the main component of the base material, The fourth subcomponent includes one or more oxides or glass compounds containing Si, and the one or more oxides include at least one element of Si and Al.

6. The multilayer ceramic capacitor according to claim 5, wherein: The size of the multilayer ceramic capacitor is 1005 or smaller, and the length×width of the 1005 size multilayer ceramic capacitor is 1.0 mm×0.5 mm.

7. The multilayer ceramic capacitor according to claim 6, wherein: A thickness of at least one of the first internal electrode and the second internal electrode is less than or equal to 0.4 μm.

8. The multilayer ceramic capacitor according to claim 1, wherein: The main component of the barium titanate-based matrix material comprises at least one compound selected from the group consisting of the following compounds: (Ba 1-x Ca x )(Ti 1-y Ca y )O3, where 0 ≤ x ≤ 0.3 and 0 ≤ y ≤ 0.1; (Ba 1-x Ca x )(Ti 1-y Zr y )O3, where 0 < x ≤ 0.3 and 0 ≤ y ≤ 0.5; and Ba(Ti 1-y Zr y )O3, where 0 < y ≤ 0.

5.

9. A multilayer ceramic capacitor comprising: a ceramic body including a dielectric layer and first and second internal electrodes, the first and second internal electrodes being arranged to face each other with each dielectric layer interposed therebetween; and a first external electrode and a second external electrode disposed on an outer surface of the ceramic body, the first external electrode being electrically connected to the first internal electrode and the second external electrode being electrically connected to the second internal electrode, Wherein, the dielectric layer comprises dielectric grains containing a dielectric ceramic composition, The dielectric ceramic composition comprises a barium titanate-based matrix material as a main component and a subcomponent, wherein the subcomponent comprises Dy and Nb as a first subcomponent, Wherein, the total content of Ti, Dy and Nb based on 100 mol of the main components of the barium titanate-based matrix material is less than or equal to 1.5 mol, wherein a thickness of at least one of the first internal electrode and the second internal electrode is less than or equal to 0.4 μm, and Wherein, Nb is arranged at the boundary of the dielectric grains.

10. The multilayer ceramic capacitor according to claim 9, wherein The content of Dy satisfies 0.7 mol<Dy<1.1 mol based on 100 mol of Ti which is a main component of the barium titanate-based matrix material.

11. The multilayer ceramic capacitor according to claim 10, wherein: The dielectric ceramic composition includes 0.1 mol or more and 2.0 mol or less of the second subcomponent based on 100 mol of Ti which is a main component of the barium titanate-based matrix material, The second subcomponent comprises one or more oxides and / or one or more carbonates, the one or more oxides comprising at least one element selected from the group consisting of Mn, V, Cr, Fe, Ni, Co, Cu and Zn, and the one or more carbonates comprising at least one element selected from the group consisting of Mn, V, Cr, Fe, Ni, Co, Cu and Zn.

12. The multilayer ceramic capacitor according to claim 11, wherein The dielectric ceramic composition includes 0.2 mol or more and less than 0.7 mol of the third subcomponent based on 100 mol of Ti which is the main component of the barium titanate-based matrix material, The third subcomponent is an oxide or a carbonate containing a fixed-valence acceptor element Mg.

13. The multilayer ceramic capacitor of claim 12, wherein: The dielectric ceramic composition includes 0.001 mol or more and 0.5 mol or less of the fourth subcomponent based on 100 mol of Ti which is the main component of the base material, The fourth subcomponent includes one or more oxides or glass compounds containing Si, and the one or more oxides include at least one element of Si and Al.

14. The multilayer ceramic capacitor of claim 13, wherein: The size of the multilayer ceramic capacitor is 1005 or smaller, and the length×width of the 1005 size multilayer ceramic capacitor is 1.0 mm×0.5 mm.

15. The multilayer ceramic capacitor of claim 9, wherein: The main component of the barium titanate-based matrix material comprises at least one compound selected from the group consisting of the following compounds: (Ba 1-x Ca x )(Ti 1-y Ca y )O3, where 0 ≤ x ≤ 0.3 and 0 ≤ y ≤ 0.1; (Ba 1-x Ca x )(Ti 1-y Zr y )O3, where 0 < x ≤ 0.3 and 0 ≤ y ≤ 0.5; and Ba(Ti 1-y Zr y )O3, where 0 < y ≤ 0.5.

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