Multilayer Ceramic Capacitors

Abstract

A multilayer ceramic capacitor is provided. The multilayer ceramic capacitor comprises: a ceramic body, a dielectric layer, a first internal electrode and a second internal electrode. 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 secondary component, the main component of the matrix material comprises BaTiO3, (Ba 1‑x Ca x )(Ti 1‑y Ca y )O3(0≤x≤0.3 and 0≤y≤0.1), (Ba 1‑x Ca x )(Ti 1‑y Zr y )O3(0≤x≤0.3 and 0≤y≤0.5) and Ba(Ti 1‑y Zr y )O3(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 May 6, 2020 and application number 202010371978.4. 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 is a recent trend toward miniaturization and multifunctionalization of electronic products and chip components, there is 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 a dielectric layer and an internal electrode layer to stack a greater number of layers. Currently, the thickness of a dielectric layer is about 0.6 μm, and efforts have been made to develop a thinner dielectric layer.

[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, it has become a problem that it is difficult to manage quality and yield.

[0007] In order to solve such problems, it is necessary to develop a new method for ensuring high reliability not only with respect to the structure of the multilayer ceramic capacitor but also, in particular, with respect to 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 one aspect of the present disclosure, a dielectric ceramic composition includes a barium titanate (BaTiO3)-based matrix material main component and a subcomponent. The subcomponent includes dysprosium (Dy) and neodymium (Nd) as a first subcomponent. Based on 100 mol of titanium (Ti) as the main component of the barium titanate-based matrix material, the total content of Nd contained in the dielectric ceramic composition is less than 0.699 mol.

[0011] According to another 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. The first outer electrode is electrically connected to the first inner electrode, the second outer electrode is electrically connected to the second inner electrode, and the dielectric layer contains dielectric grains containing a dielectric ceramic composition. The dielectric ceramic composition contains a BaTiO3-based matrix material main component and a subcomponent, wherein the subcomponent contains Dy and Nd as a first subcomponent. Based on 100 mol of Ti, the total content of Nd is less than 0.699 mol of the main component of the barium titanate-based matrix material. 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;

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

[0015] Figure 3 is a graph of IV curves according to the embodiment example and the comparative example. DETAILED DESCRIPTION

[0016] 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.

[0017] Figure 1 is a schematic perspective view of a multilayer ceramic capacitor according to an embodiment.

[0018] Figure 2 It is along Figure 1 A cross-sectional view taken along line II′ in FIG.

[0019] Reference Figure 1 and Figure 2The 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.

[0020] 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”).

[0021] Although not particularly limited, the configuration of the ceramic body 110 may be a rectangular cuboid shape as shown in the drawings.

[0022] The plurality of first internal electrodes 121 and the plurality of second internal electrodes 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.

[0023] The internal electrode may include a pair of first and second internal electrodes 121 and 122 having different polarities.

[0024] 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.

[0025] 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.

[0026] 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).

[0027] 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.

[0028] 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), or an alloy thereof.

[0029] 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.

[0030] According to an embodiment, a 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.

[0031] 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.

[0032] The dielectric layers 111 in a sintered state may be integrated into a single body so that boundaries between adjacent dielectric layers 111 may not be apparent.

[0033] 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.

[0034] 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.

[0035] In addition, the thickness of the first and second internal electrodes 121 and 122 after sintering may be 0.4 μm or less per layer.

[0036] According to an embodiment, the dielectric layer 111 includes dielectric grains including a dielectric ceramic composition. 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 neodymium (Nd) as a first subcomponent. Based on 100 mol of titanium (Ti) as the matrix material main component, the total content of Nd in the dielectric ceramic composition may be greater than 0 mol and less than 0.699 mol.

[0037] In order to develop a miniaturized multilayer ceramic capacitor with high capacitance, it has recently been required to develop a component of a dielectric composition that achieves a high dielectric constant by enhancing domain wall motion when similar-sized grains are formed in a main component of a BaTiO3-based matrix material containing an additive.

[0038] In this regard, it was shown that when donor-type dopant components are applied, the fixed source concentration in the lattice is reduced, resulting in high domain wall motion.

[0039] By applying an additive having an ion size most similar to that of barium (Ba) among various known donor-type dopants, a dielectric composition capable of minimizing lattice mismatch and achieving a high dielectric constant has been developed.

[0040] In addition, since when the content of the host donor type additive increases, generally the insulation resistance (IR) decreases and it is not easy to ensure the reduction resistance, an appropriate content ratio should be determined.

[0041] Generally, dysprosium (Dy) is the most commonly used donor-type dopant, which affects the improvement of dielectric constant and reliability of multilayer ceramic capacitors. By appropriately adjusting the content of such donor-type dopant and acceptor-type dopant, the required dielectric characteristics and reliability can be achieved.

[0042] In the present disclosure, a dielectric composition including neodymium (Nd), a rare earth element having a valence of 3 or more, is invented, which is capable of suppressing chemical defects generated by oxygen vacancies in a component of a dielectric or reducing the oxygen vacancy concentration.

[0043] The length of the ionic radius of Nd is between that of a barium (Ba) atom (the main component of the dielectric composition) and that of Dy (a donor-type dopant). Therefore, Nd can be effectively substituted at the Ba site.

[0044] In the embodiment, an optimum content ratio has been determined to ensure a high dielectric constant and excellent reliability by applying Nd in addition to Dy showing stable dielectric characteristics.

[0045] According to an embodiment, the dielectric ceramic composition includes a BaTiO3-based matrix material main component (matrix material main component) and a subcomponent, wherein the subcomponent includes Dy and Nd as a first subcomponent. The total content of Nd in the dielectric ceramic composition is less than 0.699 mol based on 100 mol of Ti as the matrix material main component.

[0046] By adjusting the total Nd content to be less than 0.699 mol based on 100 mol of Ti which is the main component of the base material, a high dielectric constant can be obtained and reliability such as insulation resistance can be improved.

[0047] Specifically, according to an embodiment, the Nd content in the dielectric ceramic composition may satisfy 0.233 mol≦Nd≦0.466 mol (based on 100 mol of Ti which is a main component of the base material).

[0048] When the Nd content satisfies 0.233 mol ≤ Nd ≤ 0.466 mol (based on 100 mol of Ti which is the main component of the base material), not only high dielectric characteristics can be obtained but also reliability improvement such as insulation resistance improvement is excellent.

[0049] According to the embodiment, for a dielectric ceramic composition included in a dielectric layer in a ceramic body, by including rare earth elements Dy and Nd as subcomponents and controlling the contents thereof, high dielectric characteristics may be obtained and reliability such as insulation resistance may be improved.

[0050] Compared with the dielectric ceramic composition of the related art, when the Nd content is less than 0.233 mol (based on 100 mol of Ti which is the main component of the base material), the dielectric constant is not significantly increased.

[0051] When the Nd content exceeds 0.466 mol (based on 100 mol of Ti which is the main component of the base material), the insulation resistance decreases due to semiconductorization.

[0052] According to an embodiment, the total content of Dy and Nd included in the dielectric ceramic composition may be greater than 0 mol and less than or equal to 1.0 mol based on 100 mol of Ti which is a main component of the base material.

[0053] Generally, as the total content of rare earth elements increases, reliability also increases. However, when the temperature (Tc) moves toward room temperature, the temperature characteristics significantly decrease. Therefore, it is preferred to adjust the Dy and Nd contents to less than or equal to 1.0 mol (based on 100 mol of Ti, the main component of the base material).

[0054] When the total content of Dy and Nd exceeds 1.0 mol based on 100 mol of Ti which is a main component of the base material, temperature characteristics such as temperature coefficient of capacitance (TCC) may deteriorate.

[0055] According to an embodiment, the first subcomponent further includes an oxide or a carbonate including lanthanum (La) which may be disposed at the boundary of the dielectric grains.

[0056] Furthermore, when a rare earth element having an ion radius larger than that of Dy, such as La, is used, Ba sites can be more effectively substituted, thereby making it more effective for reducing the oxygen vacancy concentration.

[0057] Therefore, La may be further included as the first subcomponent to ensure insulation resistance while minimizing the oxygen vacancy concentration to improve reliability.

[0058] However, if the La content is too high, the insulation resistance may decrease rapidly due to excessive semiconductorization. Therefore, the La content is preferably greater than or equal to 0.233 mol and less than or equal to 0.699 mol (based on 100 mol of Ti which is the main component of the base material).

[0059] As described above, 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 limited thereto. The thickness of the dielectric layer 111 is greater than 0.0 μm.

[0060] In addition, the size of the multilayer ceramic capacitor 100 may be 1005 (length×width, 1.0 mm×0.5 mm) or less.

[0061] In other words, 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.

[0062] In other words, since the related art multilayer ceramic capacitor has relatively thicker dielectric layers and internal electrodes than the multilayer ceramic capacitor according to the embodiment of the present disclosure, reliability is not a big problem even if the components of the dielectric ceramic composition are the same as those of the related art.

[0063] However, for the product of a multilayer ceramic capacitor to which a thin film dielectric layer and an inner electrode are applied as in the embodiment of the present disclosure, the reliability of the multilayer ceramic capacitor is important, and it is necessary to adjust the components of the dielectric ceramic composition.

[0064] That is, in an embodiment, even when the dielectric layer 111 is a thin film having a thickness less than or equal to 0.4 μm, reliability (such as insulation resistance) can be improved by including Dy and Nd as first subcomponents and adjusting the Nd content to be less than 0.699 mol (based on 100 mol of Ti, the main component of the base material), and in more detail, adjusting the Nd content to satisfy 0.233 mol ≤ Nd ≤ 0.466 mol (based on 100 mol of Ti, the main component of the base material).

[0065] However, thin film does not mean that the thickness of the dielectric layer 111 and the internal electrodes 121 and 122 is less than or equal to 0.4 μm, but may be understood as meaning that the dielectric layer and the internal electrodes are thinner than those of related art products.

[0066] Hereinafter, each component of the dielectric ceramic composition according to the embodiment will be described in more detail.

[0067] a) Main component of the matrix material

[0068] The dielectric ceramic composition according to an embodiment of the present disclosure may include a main component of the matrix material represented by BaTiO3.

[0069] According to an embodiment, the main component of the matrix material includes at least one 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.

[0070] The dielectric ceramic composition according to an embodiment may have a room temperature dielectric constant greater than or equal to 2000.

[0071] 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 150 nm.

[0072] b) First sub-component

[0073] According to an embodiment of the present disclosure, the dielectric ceramic composition substantially includes Dy and Nd as elements of the first sub-component and may additionally include an oxide and / or carbonate of lanthanum (La) in an amount greater than or equal to 0.233 mol and less than or equal to 0.699 mol (based on Ti of 100 mol of the main component of the matrix material).

[0074] In an embodiment, the first sub-component is used to suppress the reliability degradation of the multilayer ceramic capacitor to which the dielectric ceramic composition is applied.

[0075] When the La content is less than 0.233 mol (based on Ti of 100 mol of the main component of the matrix material), the dielectric constant does not increase. When the La content exceeds 0.699 mol (based on Ti of 100 mol of the main component of the matrix material), the insulation resistance or the dissipation factor (DF) decreases.

[0076] 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 Nd as the first subcomponent, adjusting the Nd content present in the dielectric ceramic composition to less than 0.699 mol (based on 100 mol of Ti, the main component of the base material), and in more detail, adjusting the Nd content in the dielectric ceramic composition to satisfy 0.233 mol ≤ Nd ≤ 0.466 mol (based on 100 mol of Ti, the main component of the base material). The Nd content of the present disclosure may be the Nd content contained in the dielectric layer 111.

[0077] c) Second subcomponent

[0078] According to an embodiment of the present disclosure, the dielectric ceramic composition may include one or more oxides including 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 / or one or more carbonates including at least one element selected from the group consisting of Mn, V, Cr, Fe, Ni, Co, Cu, and Zn as a second subcomponent.

[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 / or 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 (based on 100 mol of Ti which is the main component of the base material).

[0080] The second auxiliary component 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.

[0081] The content of the second subcomponent, the third subcomponent, and the fourth subcomponent described may be the amount of Ti contained in the dielectric ceramic composition based on 100 mol of the main component of the matrix material, and may be defined as the molar number of metal ions contained in each subcomponent. The content of the second subcomponent, the third subcomponent, and the fourth subcomponent disclosed in the present invention may be the content contained in the dielectric layer 111.

[0082] When the content of the second subcomponent is less than 0.1 mol based on 100 mol of Ti which is the main component of the base material, the firing temperature increases and the high-temperature withstand voltage characteristics may be slightly reduced.

[0083] When the content of the second subcomponent is greater than 2.0 mol based on 100 mol of Ti which is the main component of the base material, high-temperature withstand voltage characteristics and room-temperature resistivity may be deteriorated.

[0084] In detail, the dielectric ceramic composition according to the embodiment of the present disclosure may include 0.1 mol or more and 2.0 mol or less (based on 100 mol of Ti of the main component of the base material) of the second auxiliary component. 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 including 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 0.001 mol and less than or equal to 0.5 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 0.001 mol or more and 0.5 mol or less (based on 100 mol of Ti as 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 0.5 mol based on 100 mol of Ti which is the main component of the base material, the dielectric constant may decrease, which may be problematic.

[0090] However, according to an embodiment, in order to maximize the reliability improvement caused by the n-type, it is preferred to include 0.5 mol of the third subcomponent (based on 100 mol of Ti as the main component of the base material), but is not limited thereto. The content of the third subcomponent may be included in an amount less than or equal to 0.5 mol or slightly greater than 0.5 mol.

[0091] e) The fourth component

[0092] 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 silicon (Si) as a fourth subcomponent.

[0093] 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 4.0 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.

[0094] The content of the fourth subcomponent may be the content of Si and Al elements contained in the fourth subcomponent regardless of the addition form such as glass, oxide, or carbonate.

[0095] 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.

[0096] When the fourth subcomponent content exceeds 4.0 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.

[0097] In detail, according to the embodiment, when the dielectric ceramic composition includes less than or equal to 4.0 mol of Al, grain growth may be controlled to be uniform, thereby improving withstand voltage and reliability as well as DC bias characteristics.

[0098] 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.

[0099] (Example of Embodiment)

[0100] The dielectric layer is formed by adding additives (such as Dy, Nd, La, Al, Mg, Mn, etc.), a binder and an organic solvent (such as ethanol) to a dielectric powder 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.

[0101] All element additives having a particle size of 40% or less based on BaTiO3 are monodispersed and added.

[0102] Specifically, the content of Dy and Nd present in the dielectric slurry is less than or equal to 1.0 mol based on 100 mol of Ti which is a main component of the base material.

[0103] In Embodiment Example 1, 0.699 mol of Dy and 0.233 mol of Nd were added to the dielectric slurry based on 100 mol of Ti which was the main component of the base material, and in Embodiment Example 2, 0.466 mol of Dy and 0.466 mol of Nd were added to the dielectric slurry.

[0104] 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 a slurry and performing a doctor blade method using the slurry.

[0105] 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.

[0106] 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.

[0107] Then, the cut laminated body is heated to remove the binder, and fired in a high-temperature reducing atmosphere to form a ceramic body.

[0108] During the firing process, 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.

[0109] A termination process and electrode firing are performed on the fired ceramic body using a copper (Cu) paste, and external electrodes are formed.

[0110] 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.

[0111] (Comparative Example 1)

[0112] Comparative Example 1 represents a conventional case in which 0.932 mol of Dy was added based on 100 mol of Ti which was a main component of the base material. The remaining manufacturing process was the same as that described in the embodiment example.

[0113] (Comparative Example 2)

[0114] In Comparative Example 2, 0.233 mol of Dy and 0.699 mol of Nd were added based on 100 mol of Ti which was the main component of the base material. The remaining manufacturing process was the same as that described in the embodiment example.

[0115] (Comparative Example 3)

[0116] In Comparative Example 3, 0.932 mol of Nd was added based on 100 mol of Ti which was the main component of the base material. The remaining manufacturing process was the same as that described in the embodiment example.

[0117] The dielectric constant, dissipation factor (DF), and resistivity of samples of Embodiment Examples 1 and 2 and Comparative Examples 1 to 3 (prototype multilayer ceramic capacitors (MLCCs) manufactured as above) were tested, and their results were evaluated.

[0118] The tests were carried out under the following three conditions, namely 1140°C (average 1135°C), 1160°C (average 1157°C) and 1180°C (average 1172°C).

[0119] Table 1 below shows dielectric constants, DF, and IR of sheets of prototype MLCCs according to experimental examples (Embodiment Examples 1 and 2 and Comparative Examples 1 to 3).

[0120] [Table 1]

[0121]

[0122] Referring to Table 1, compared with Comparative Example 1 in which Nd is not added, in Example 1 and Example 2, by adding less than 0.699 mol of Nd (based on 100 mol of Ti, the main component of the base material), the dielectric constant and DF can be improved, and although the resistivity is slightly reduced, it is still within the allowable range. In Comparative Examples 2 and 3, when the Nd content is greater than or equal to 0.699 mol (based on 100 mol of Ti, the main component of the base material), although the dielectric constant and DF are improved, the resistivity is very low, exceeding the allowable range, resulting in overcurrent.

[0123] The Dy and Nd contents of Example 1 and Example 2 are less than or equal to 1.0 mol (based on 100 mol of Ti as the main component of the base material), and they satisfy 0.233 mol ≤ Nd ≤ 0.466 mol (based on 100 mol of Ti as the main component of the base material). Compared with Comparative Example 1, the dielectric constant and DF of Example 1 and Example 2 are improved, and the reliability (such as resistivity, etc.) is improved compared with Comparative Example 2 and Comparative Example 3.

[0124] Figure 3 IV curves according to the embodiment example and the comparative example are shown.

[0125] Reference Figure 3 Embodiment Examples 1 and 2 in which the Nd content satisfies 0.233 mol ≤ Nd ≤ 0.466 mol (based on 100 mol of Ti which is the main component of the base material) achieve stable resistivity similar to that of Comparative Example 1 in which only Dy is included.

[0126] According to embodiments, a dielectric ceramic composition may have improved dielectric constant, DF, and reliability such as improved resistivity by including a new rare earth element Nd as a subcomponent while controlling the content of Nd.

[0127] While 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 connected to the first internal electrode and the second external electrode being connected to the second internal electrode, Wherein, the dielectric layer comprises dielectric grains containing a dielectric ceramic composition, The dielectric ceramic composition contains a main component of a matrix material and a sub-component. The main component of the matrix material includes one selected from the group consisting of BaTiO3, (Ba 1-x Ca x )(Ti 1-y Ca y )O3, (Ba 1-x Ca x )(Ti 1-y Zr y )O3, and Ba(Ti 1-y Zr y )O3. In (Ba 1-x Ca x )(Ti 1-y Ca y )O3, 0 ≤ x ≤ 0.3 and 0 ≤ y ≤ 0.

1. In (Ba 1-x Ca x )(Ti 1-y Zr y )O3, 0 ≤ x ≤ 0.3 and 0 ≤ y ≤ 0.

5. In Ba(Ti 1-y Zr y )O3, 0 < y ≤ 0.

5. The sub-component contains Dy and Nd as the first sub-component. The content of Nd is less than 0.699 mol based on 100 mol of Ti, which is the main component of the matrix material, and The subcomponent further includes La as a first subcomponent, and the content of La is greater than or equal to 0.233 mol and less than or equal to 0.699 mol based on 100 mol of Ti as a main component of the base material, wherein La is provided at the boundary of the dielectric grains.

2. The multilayer ceramic capacitor according to claim 1, wherein: The content of Nd is greater than or equal to 0.233 mol based on 100 mol of Ti which is a main component of the base material.

3. The multilayer ceramic capacitor according to claim 2, wherein: The content of Nd is less than or equal to 0.466 mol based on 100 mol of Ti which is a main component of the base material.

4. The multilayer ceramic capacitor according to claim 3, wherein: The total content of Ti, Dy and Nd based on 100 mol of the main component of the base material is less than or equal to 1.0 mol.

5. The multilayer ceramic capacitor according to claim 1, wherein: The multilayer ceramic capacitor has a size of 1005 or less, and the length×width of the 1005 size is 1.0 mm×0.5 mm.

6. The multilayer ceramic capacitor according to claim 1, 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 the main component of the base material, The second subcomponent includes one or more oxides selected from the group consisting of Mn oxides, V oxides, Cr oxides, Fe oxides, Ni oxides, Co oxides, Cu oxides and Zn oxides and / or includes one or more carbonates selected from the group consisting of Mn carbonates, V carbonates, Cr carbonates, Fe carbonates, Ni carbonates, Co carbonates, Cu carbonates and Zn carbonates.

7. The multilayer ceramic capacitor according to claim 1, wherein: The dielectric ceramic composition includes 0.001 mol or more and 0.5 mol or less of the third subcomponent based on 100 mol of Ti which is the main component of the base material, The third subcomponent includes an oxide or a carbonate containing a fixed-valence acceptor element Mg.

8. The multilayer ceramic capacitor according to any one of claims 1 to 7, wherein: The thickness of the first internal electrode and the second internal electrode is less than or equal to 0.4 μm.

9. The multilayer ceramic capacitor according to any one of claims 1 to 7, wherein: The thickness of the dielectric layer is less than or equal to 0.4 μm.

Images