Dielectric ceramic composition and multilayer ceramic capacitor containing the same

Abstract

To provide a dielectric ceramic composition capable of enhancing the reliability, and a multilayer ceramic capacitor including the same.SOLUTION: In one embodiment, a dielectric ceramic composition includes a BaTiO3-based base material main component and a subcomponent, where the subcomponent includes zinc oxide (ZnO) as a first subcomponent, with the content of the zinc oxide (ZnO) being 0.1 mol% or more and less than 0.4 mol% based on 100 mol% of the base material main component. Also provided is a multilayer ceramic capacitor including the same.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a dielectric ceramic composition that can improve reliability and a multilayer ceramic capacitor containing the same. [Background technology]

[0002] Generally, electronic components using ceramic materials, such as capacitors, inductors, piezoelectric elements, varistors, or thermistors, comprise a ceramic body made of ceramic material, internal electrodes formed inside the body, and external electrodes arranged on the surface of the ceramic body so as to be connected to the internal electrodes.

[0003] Recently, with the miniaturization and multi-functionality of electronic products, chip components are also becoming smaller and more sophisticated. As a result, there is a demand for multilayer ceramic capacitors that are small in size and have high capacitance.

[0004] One method for achieving both miniaturization and high capacitance in multilayer ceramic capacitors is to reduce the thickness of the internal dielectric and electrode layers and stack a large number of them. Currently, the dielectric layer thickness is around 0.6 μm, and development to further reduce it is ongoing.

[0005] Under these circumstances, ensuring the reliability of the dielectric layer has become a crucial challenge for dielectric materials.

[0006] Furthermore, the dielectric layer of a thin film has the problem of being subjected to a large electric field per unit thickness and being sensitive to temperature changes, making it difficult to achieve effective capacitance and temperature characteristics under actual operating conditions.

[0007] Therefore, in order to solve these problems, there is an urgent need to develop dielectric materials that exhibit minimal changes in dielectric constant due to external electric fields (DC) and temperature changes. [Overview of the project] [Problems that the invention aims to solve]

[0008] The object of the present invention is to provide a dielectric ceramic composition that can improve reliability and a multilayer ceramic capacitor containing the same. [Means for solving the problem]

[0009] One embodiment of the present invention provides a dielectric ceramic composition comprising a BaTiO3-based matrix main component and a minor component, wherein the minor component includes zinc oxide (ZnO) as the first minor component, and the zinc oxide (ZnO) content is 0.1 mol% or more and less than 0.4 mol% relative to 100 mol% of the matrix main component.

[0010] Another embodiment of the present invention provides a multilayer ceramic capacitor comprising a ceramic body including a dielectric layer and first and second internal electrodes arranged facing each other with the dielectric layer in between; a first external electrode arranged outside the ceramic body and electrically connected to the first internal electrode; and a second external electrode electrically connected to the second internal electrode, wherein the dielectric layer comprises dielectric grains comprising a dielectric ceramic composition, the dielectric ceramic composition comprising a BaTiO3-based matrix main component and a minor component, the minor component comprising zinc oxide (ZnO) as the first minor component, and the zinc oxide (ZnO) content being 0.1 mol% or more and less than 0.4 mol% with respect to 100 mol% of the matrix main component. [Effects of the Invention]

[0011] According to one embodiment of the present invention, by including zinc oxide (ZnO) as a secondary component in the dielectric porcelain composition contained in the dielectric layer within the ceramic body, and by controlling its content, grain growth can be suppressed and low-temperature densification can be achieved. This makes it possible to reduce the rate of change of effective capacity under a DC electric field and improve reliability. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic perspective view showing a multilayer ceramic capacitor according to one embodiment of the present invention. [Figure 2] This is a cross-sectional view along the line I-I' in Figure 1. [Figure 3] This graph shows the dielectric grain size for examples and comparative examples according to one embodiment of the present invention. [Figure 4] (a) and (b) are graphs showing the results of reliability tests conducted under harsh conditions for examples and comparative examples of one embodiment of the present invention. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described below with reference to specific embodiments and accompanying drawings. However, embodiments of the present invention can be modified into several other forms, and the scope of the present invention is not limited to the embodiments described below. Furthermore, embodiments of the present invention are provided to give a more complete explanation of the present invention to a person with average skill in the art. Accordingly, the shapes and sizes of elements in the drawings may be enlarged or reduced (or highlighted or simplified) for a clearer explanation, and elements indicated by the same reference numerals in the drawings are the same elements.

[0014] Figure 1 is a schematic perspective view showing a multilayer ceramic capacitor according to one embodiment of the present invention, and Figure 2 is a cross-sectional view along the line I-I' in Figure 1.

[0015] Referring to Figures 1 and 2, a multilayer ceramic capacitor 100 according to one embodiment of the present invention includes a ceramic body 110 including a dielectric layer 111, and first internal electrodes 121 and second internal electrodes 122 arranged facing each other with the dielectric layer 111 in between, and a first external electrode 131 arranged outside the ceramic body 110 and electrically connected to the first internal electrode 121, and a second external electrode 132 electrically connected to the second internal electrode 122.

[0016] In the multilayer ceramic capacitor 100 according to an embodiment of the present invention, the "length direction" is defined as the "L" direction in FIG. 1, the "width direction" is defined as the "W" direction, and the "thickness direction" is defined as the "T" direction herein. Here, the "thickness direction" can be used in the same concept as the direction in which dielectric layers are stacked, that is, the "stacking direction".

[0017] There is no particular limitation on the shape of the ceramic body 110, but as shown in the drawings, it can be in a hexahedron shape.

[0018] One end of each of the plurality of internal electrodes 121 and 122 formed inside the ceramic body 110 is exposed on one surface of the ceramic body or on the other surface facing the one surface.

[0019] The internal electrodes 121 and 122 can be paired as a first internal electrode 121 and a second internal electrode 122 having different polarities from each other.

[0020] One end of the first internal electrode 121 can be exposed on one surface of the ceramic body, and one end of the second internal electrode 122 can be exposed on the other surface facing the one surface.

[0021] First and second external electrodes 131 and 132 are formed on one surface of the ceramic body 110 and on the other surface facing the one surface, and can be electrically connected to the internal electrodes.

[0022] The materials for forming the first and second internal electrodes 121 and 122 are not particularly limited, and the first and second internal electrodes 121 and 122 can be formed using a conductive paste containing one or more substances such as silver (Ag), lead (Pb), platinum (Pt), nickel (Ni), and copper (Cu).

[0023] The first and second external electrodes 131 and 132 can be electrically connected to the first and second internal electrodes 121 and 122 in order to form a capacitance, and the second external electrode 132 can be connected to a potential different from that of the first external electrode 131.

[0024] The conductive material contained in the first and second external electrodes 131 and 132 described above is not particularly limited, but nickel (Ni), copper (Cu), or alloys thereof can be used.

[0025] The thickness of the first and second external electrodes 131 and 132 described above can be appropriately determined depending on the application, etc., and is not particularly limited, but may be, for example, 10 to 50 μm.

[0026] According to one embodiment of the present invention, the raw material for forming the dielectric layer 111 is not particularly limited as long as sufficient capacitance can be obtained, and may be, for example, barium titanate (BaTiO3) powder.

[0027] The material used to form the dielectric layer 111 can be a powder such as barium titanate (BaTiO3) to which various additives, organic solvents, plasticizers, binders, dispersants, etc., can be added according to the purpose of the present invention.

[0028] The dielectric layer 111 described above is in a sintered state, and the grain boundaries between adjacent dielectric layers can be so integrated that they cannot be observed.

[0029] First and second internal electrodes 121 and 122 can be formed on the dielectric layer 111, and the internal electrodes 121 and 122 can be formed inside the ceramic body with a dielectric layer in between by sintering.

[0030] The thickness of the dielectric layer 111 can be arbitrarily changed according to the capacitance design of the capacitor. In one embodiment of the present invention, the thickness of the dielectric layer after firing may preferably be 0.4 μm or less per layer.

[0031] Furthermore, the thickness of the first and second internal electrodes 121 and 122 after firing may preferably be 0.4 μm or less per layer.

[0032] According to one embodiment of the present invention, the dielectric layer 111 comprises dielectric grains containing a dielectric ceramic composition, the dielectric ceramic composition comprising a BaTiO3-based base material main component and a minor component, the minor component comprising zinc oxide (ZnO) as the first minor component, and the zinc oxide (ZnO) content being 0.1 mol% or more and less than 0.4 mol% relative to 100 mol% of the base material main component.

[0033] In general, in high-frequency, low-electric-field environments, it is necessary to suppress grain growth of the dielectric material during firing in order to reduce the rate of change of effective capacitance and ensure temperature stability.

[0034] To suppress grain growth in ceramic materials, the drag effect caused by grain boundary segregation is used. When the drag effect occurs, the mobility of dielectric grains within the grain boundaries decreases, thereby suppressing grain growth. Therefore, in one embodiment of the present invention, grain growth is suppressed by adding zinc oxide (ZnO) as an additive that can induce the drag effect, and by controlling its content, a reduction in the rate of change of effective capacity under a DC electric field and an improvement in reliability are achieved.

[0035] Generally, zinc (Zn) ions are small in size and are suitable for substitution at the B site within perovskite structures, such as ABO3.

[0036] However, its valence is low relative to Ti, making it difficult for it to actually be dissolved in solid solution.

[0037] Zinc (Zn) ions have a +2 valency, and due to their low valency, they are suitable for substitution at Ba sites, i.e., A sites, which also have a +2 valency. Furthermore, due to the large size mismatch with the larger ion size of Ba, the solid solubility limit is very low.

[0038] Therefore, when zinc oxide (ZnO) is added, most of the zinc oxide (ZnO) is not dissolved in the lattice but is segregated at the grain boundaries in the form of zinc oxide (ZnO). This segregated zinc oxide (ZnO) at the grain boundaries induces a drag effect that hinders grain boundary movement during grain growth, and as a result, suppresses grain growth in ceramic materials.

[0039] When grain growth in ceramic materials is suppressed, the width of domain walls within dielectric grains decreases, and the mobility of domain walls increases under high-frequency, low-electric-field conditions.

[0040] This leads to an increase in DC effective capacitance under high frequency and low electric field conditions. Furthermore, the domain size is reduced, resulting in a decrease in nominal capacitance at room temperature. In addition, the proportion of the shell portion in the dielectric grain of the core-shell structure can be reduced, improving temperature stability.

[0041] According to one embodiment of the present invention, the dielectric ceramic composition comprises a BaTiO3-based matrix main component and a minor component, the minor component comprising zinc oxide (ZnO) as the first minor component, and by satisfying that the zinc oxide (ZnO) content is 0.1 mol% or more and less than 0.4 mol% relative to 100 mol% of the matrix main component, grain growth can be suppressed and low-temperature densification can be achieved. This makes it possible to reduce the rate of change of effective capacity under a DC electric field and improve reliability.

[0042] When the zinc oxide (ZnO) content is less than 0.1 mol% relative to 100 mol% of the main component of the base material, the zinc oxide (ZnO) content is low, and the grain growth inhibitory effect is minimal.

[0043] In contrast, if the zinc oxide (ZnO) content is 0.4 mol% or more relative to 100 mol% of the main component of the base material, the amount of zinc oxide (ZnO), which has semiconductor properties, becomes too large. This leads to segregation at the grain boundaries of the dielectric grain, reducing the resistance of the grain boundaries and causing reliability problems.

[0044] When the zinc oxide (ZnO) content satisfies the requirement of 0.1 mol% or more and less than 0.4 mol% relative to 100 mol% of the main component of the base material, it can be confirmed that densification of the dielectric material occurs at a firing temperature 20°C lower than that of the same model, demonstrating a clear grain growth suppression effect.

[0045] On the other hand, according to one embodiment of the present invention, the above-mentioned auxiliary component includes magnesium (Mg) as a second auxiliary component, and the total content of zinc oxide (ZnO) and magnesium (Mg) can be less than 0.8 mol% relative to 100 mol% of the main component of the base material.

[0046] While an increase in the total content of zinc oxide (ZnO) and magnesium (Mg) is advantageous in terms of improving reliability, exceeding a certain amount leads to semiconductor formation, reducing the insulating properties and decreasing sinterability. Therefore, it is preferable that the total content of zinc oxide (ZnO) and magnesium (Mg) be less than 0.8 mol% relative to 100 mol% of the main component of the base material.

[0047] In other words, if the total content of zinc oxide (ZnO) and magnesium (Mg) is 0.8 mol% or more relative to 100 mol% of the main component of the base material, excessive content may result in insufficient sinterability, potentially leading to reliability problems such as insufficient capacity and a decrease in dielectric breakdown voltage (BDV).

[0048] As described above, the multilayer ceramic capacitor 100 according to one embodiment of the present invention is an ultra-small, high-capacitance product characterized in that the thickness of the dielectric layer 111 is 0.4 μm or less, and the thickness of the first and second internal electrodes 121 and 122 is 0.4 μm or less, but is not necessarily limited thereto.

[0049] Furthermore, the size of the multilayer ceramic capacitor 100 can be 1005 (length × width, 1.0 mm × 0.5 mm) or less.

[0050] In other words, since the multilayer ceramic capacitor 100 according to one embodiment of the present invention is an ultra-small, high-capacitance product, the dielectric layer 111 and the first and second internal electrodes 121 and 122 are thinner than those of conventional products. In the case of products that use such thin dielectric layers and internal electrodes, research to reduce the rate of change of effective capacitance under a DC electric field and to improve reliability is a very important issue.

[0051] In other words, in the case of conventional multilayer ceramic capacitors, the dielectric layer and internal electrodes included in the multilayer ceramic capacitor according to one embodiment of the present invention have relatively thicker components. Therefore, even if the composition of the dielectric ceramic composition is the same as in the conventional case, reliability has not been a major issue.

[0052] However, in products to which thin dielectric layers and internal electrodes are applied, such as in one embodiment of the present invention, it is important to reduce the rate of change of effective capacitance and improve reliability under a DC electric field of the multilayer ceramic capacitor, and for this purpose, it is necessary to adjust the composition of the dielectric ceramic composition.

[0053] In other words, in one embodiment of the present invention, by adjusting the zinc oxide (ZnO) content to satisfy 0.1 mol% or more and less than 0.4 mol% relative to 100 mol% of the main component of the base material, and in particular by adjusting the total content of zinc oxide (ZnO) and magnesium (Mg) to less than 0.8 mol% relative to 100 mol% of the main component of the base material, grain growth suppression and low-temperature densification can be achieved even in the case of a thin film with a dielectric layer 111 thickness of 0.4 μm or less. This makes it possible to reduce the rate of change of effective capacity under a DC electric field and improve reliability.

[0054] However, the term "thin film" as used above does not mean that the dielectric layer 111 and the first and second internal electrodes 121 and 122 have a thickness of 0.4 μm or less. Rather, it should be understood as a concept that includes dielectric layers and internal electrodes with thinner thicknesses than those of conventional products.

[0055] Hereinafter, each component of the dielectric ceramic composition according to an embodiment of the present invention will be described more specifically.

[0056] a) Base material main component The dielectric ceramic composition according to an embodiment of the present invention can include a base material main component represented by BaTiO3.

[0057] According to an embodiment of the present invention, the above base material main component is BaTiO3, (Ba 1-x Ca x )(Ti 1-y Ca y )O3 (where x is 0 ≦ x ≦ 0.3 and y is 0 ≦ y ≦ 0.1), (Ba 1-x Ca x )(Ti 1-y Zr y )O3 (where x is 0 ≦ x ≦ 0.3 and y is 0 ≦ y ≦ 0.5), and Ba(Ti 1-y Zr y )O3 (where 0 < y ≦ 0.5), and includes one or more selected from the group consisting of, but is not necessarily limited thereto.

[0058] The dielectric ceramic composition according to an embodiment of the present invention can have a room temperature dielectric constant of 2000 or more.

[0059] The above base material main component is not particularly limited, but the average particle size of the main component powder may be 40 nm or more and 200 nm or less.

[0060] b) First sub-component According to an embodiment of the present invention, the above dielectric ceramic composition can include an oxide or carbonate containing at least one of Mn, V, Cr, Fe, Ni, Co, Cu, and Zn as the first sub-component element.

[0061] As the above first sub-component, an oxide or carbonate containing at least one of Mn, V, Cr, Fe, Ni, Co, Cu, and Zn can be included in a content of 0.1 to 2.0 mol% with respect to 100 mol% of the above base material main component.

[0062] The above-mentioned first minor component prevents a decrease in the firing temperature of the multilayer ceramic capacitor to which the dielectric ceramic composition is applied, and also plays a role in improving the high-temperature withstand voltage characteristics.

[0063] The content of the first minor component described above and the content of the second to fourth minor components described later are amounts contained in 100 mol% of the base material powder, and can be defined in particular as the mol% of metal ions contained in each minor component.

[0064] If the content of the first minor component mentioned above is less than 0.1 mol%, the firing temperature will be higher, and the high-temperature withstand voltage characteristics may be slightly reduced.

[0065] If the content of the above-mentioned first minor component exceeds 2.0 mol%, the high-temperature withstand voltage characteristics and room-temperature resistivity may decrease.

[0066] In particular, a dielectric ceramic composition according to one embodiment of the present invention may contain a first minor component having an content of 0.1 to 2.0 mol% relative to 100 mol% of the main component of the base material. This enables low-temperature firing and allows for high high-temperature withstand voltage characteristics.

[0067] c) Second subcomponent According to one embodiment of the present invention, the dielectric ceramic composition may contain a second minor component which is an oxide or carbonate containing the fixed-valence acceptor element Mg.

[0068] The above-mentioned fixed-valence acceptor element, Mg, may contain a second minor component of 0.2 to 0.7 mol% relative to 100 mol% of the main component of the base material.

[0069] The above-mentioned second minor component is a valence-fixed acceptor and a compound containing the same, which can act as an acceptor and play a role in reducing the electron concentration. By adding 0.2 to 0.7 mol% of the above-mentioned fixed-valence acceptor element Mg, which is the second minor component, per 100 moles of the main component of the base material, the effect of improving reliability through n-type formation can be maximized.

[0070] If the content of the above-mentioned second minor component exceeds 0.7 mol% relative to 100 mol% of the base material powder, it is undesirable because it results in a problem of low dielectric constant or dielectric breakdown voltage (BDV).

[0071] d) Third subcomponent According to one embodiment of the present invention, the dielectric ceramic composition may include, as a third minor component, an oxide containing at least one of Si and Al, or a glass compound containing Si.

[0072] The above dielectric ceramic composition may further contain 0.0 to 0.5 mol% of a third minor component, which is an oxide containing at least one of Si and Al, or a glass compound containing Si, based on 100 mol% of the main base material component.

[0073] The content of the third minor component described above can be determined based on the content of at least one of the elements Si and Al contained in the third minor component, without distinguishing between its additive form, such as glass, oxide, or carbonate.

[0074] The above-mentioned third subcomponent plays a role in reducing the firing temperature and improving the high-temperature withstand voltage characteristics of multilayer ceramic capacitors to which the dielectric ceramic composition is applied.

[0075] If the content of the above-mentioned third minor component exceeds 0.5 mol% relative to 100 mol% of the above-mentioned main component of the base material, it is undesirable because it reduces sinterability and density, and causes problems such as secondary phase formation.

[0076] In particular, according to one embodiment of the present invention, by including Al in the dielectric ceramic composition in an amount of 0.5 mol% or less, the Al acts as an acceptor, which in turn reduces the electron concentration, thus improving reliability.

[0077] e) Fourth subcomponent According to one embodiment of the present invention, the dielectric ceramic composition may contain 0.001 to 4.0 mol% of a fourth minor component, which is an oxide or carbonate containing at least one of Dy, Y, Ho, Er, Ce, Nd, Pm, Eu, Gd, Tm, Yb, Lu, La, and Sm, relative to 100 mol% of the main component of the base material.

[0078] The fourth subcomponent described above plays a role in preventing a decrease in the reliability of a multilayer ceramic capacitor to which the dielectric ceramic composition is applied in one embodiment of the present invention.

[0079] If the content of the above fourth minor component exceeds 4.0 mol%, it may lead to problems such as decreased reliability or a decrease in the dielectric constant of the dielectric ceramic composition, resulting in poor high-temperature withstand voltage characteristics.

[0080] In particular, according to one embodiment of the present invention, the lanthanum (La) among the fourth subcomponents can be placed at the grain boundaries of the dielectric grain.

[0081] On the other hand, using a rare earth element with a larger ionic radius than dysprosium (Dy), such as lanthanum (La), allows for more effective substitution of the Ba site, thus being even more effective in reducing the oxygen vacancy defect concentration.

[0082] Therefore, in order to improve reliability and minimize the oxygen vacancy defect concentration, and to ensure insulation resistance, lanthanum (La) may be further included as a fourth minor component.

[0083] However, if the lanthanum (La) content is too high, there is a problem that the insulation resistance will drop sharply due to excessive semiconductorization. Therefore, it is preferable that the content be between 0.233 mol% and 0.699 mol% relative to 100 mol% of the main component of the base material.

[0084] If the lanthanum (La) content is less than 0.233 mol%, there is no effect on improving the dielectric constant. If it exceeds 0.699 mol%, problems such as a decrease in insulation resistance or a decrease in dielectric loss (dissipation factor, Df) may occur. [Examples]

[0085] The present invention will be described in more detail below with reference to examples and comparative examples, but this is intended to aid in a concrete understanding of the invention, and the scope of the present invention is not limited by these examples.

[0086] (Examples) Examples of the present invention involve dielectric raw material powder containing barium titanate (BaTiO3) powder. 、M g, Zn including Additives, binders, and ethanol including An organic solvent was added and wet-mixed to form a dielectric slurry. This dielectric slurry was then applied to a carrier film and dried to form a ceramic green sheet. This allowed for the formation of a dielectric layer.

[0087] In this process, the additives were monodispersed so that the size of all elements relative to the barium titanate was 40% or less.

[0088] In the embodiment of the present invention, the zinc oxide (ZnO) content is manufactured to satisfy the requirement of 0.1 mol% or more and less than 0.4 mol% relative to 100 mol% of the main component of the base material, and in particular, the total content of zinc oxide (ZnO) and magnesium (Mg) is manufactured to be less than 0.8 mol% relative to 100 mol% of the main component of the base material.

[0089] In Example 1 of the above examples, zinc oxide (ZnO) was added in such a way that its content was 0.1 mol% relative to 100 mol% of the main component of the base material.

[0090] Next, in Example 2, zinc oxide (ZnO) was added so that its content was 0.2 mol% relative to 100 mol% of the main component of the base material.

[0091] The above-mentioned ceramic green sheet can be produced by mixing ceramic powder, a binder, and a solvent to create a slurry, and then fabricating the slurry into a sheet with a thickness of several micrometers using the doctor blade method.

[0092] Subsequently, a conductive paste for the internal electrode can be prepared, containing 40 to 50 parts by weight of nickel powder with an average particle size of 0.1 to 0.2 μm.

[0093] The conductive paste for the internal electrodes was applied to the green sheet using a screen printing method to form the internal electrodes. After the green sheets with the internal electrode patterns were stacked to form a laminate, the laminate was compressed and cut.

[0094] Next, the cut laminate was heated to remove the binder, and then fired in a high-temperature reducing atmosphere to form the ceramic body.

[0095] In the above firing process, the material was fired at a temperature of 1100-1200°C for 2 hours in a reducing atmosphere (0.1% H2 / 99.9% N2, H2O / H2 / N2 atmosphere), and then re-oxidized and heat-treated at a nitrogen (N2) atmosphere of 1000°C for 3 hours.

[0096] Next, the external electrodes were completed by applying copper (Cu) paste to the fired ceramic body and then undergoing electrode firing.

[0097] Furthermore, the dielectric layer 111 inside the ceramic body 110, as well as the first and second internal electrodes 121 and 122, were manufactured so that their thickness after firing is 0.4 μm or less.

[0098] (Comparative Example 1) In the case of Comparative Example 1, zinc oxide (ZnO) is not added, and the other manufacturing processes are the same as in the example described above.

[0099] (Comparative Example 2) In Comparative Example 2, zinc oxide (ZnO) was added in such a way that its content was 0.4 mol% relative to 100 mol% of the main component of the base material, and the other manufacturing processes were the same as in the example described above.

[0100] As described above, the completed prototype multilayer ceramic capacitor (Proto-type MLCC) samples in Examples 1 and 2, and Comparative Examples 1 and 2, were subjected to dielectric loss (DF) and effective capacitance change rate tests at 1V DC and 3V DC.

[0101] Table 1 below shows the dielectric loss (Dissipation Factor, DF) and the rate of change in effective capacitance at 1V DC and 3V DC for prototype multilayer ceramic capacitor (Prototype MLCC) chips based on experimental examples (Examples 1 and 2, Comparative Examples 1 and 2).

[0102] [Table 1]

[0103] Referring to Table 1 above, it can be seen that in the conventional case, as in Comparative Example 1 where zinc oxide (ZnO) is not added, there is a problem with the dielectric loss (dissipation factor, DF), and there is a problem with a high rate of change in effective capacity at 1V DC and 3V DC.

[0104] In contrast, Examples 1 and 2 of the present invention show that when the zinc oxide (ZnO) content is 0.1 mol% or more and less than 0.4 mol% relative to 100 mol% of the main component of the base material, there is an effect of reducing the dielectric loss (Dissipation Factor, DF) and the rate of change of effective capacitance under a DC electric field.

[0105] However, in Comparative Example 2, where zinc oxide (ZnO) was added to a content of 0.4 mol% relative to 100 mol% of the main component of the base material, there was an effect of reducing the dielectric loss (Dissipation Factor, DF) and the rate of change of effective capacity under a DC electric field, but as described later, there was a problem in that a significant decrease in reliability occurred.

[0106] Figure 3 is a graph showing the dielectric grain size for examples and comparative examples according to one embodiment of the present invention.

[0107] Referring to Figure 3, it can be seen that in the conventional case, Comparative Example 1, in which zinc oxide (ZnO) was not added, firing at 1,140°C did not have any grain growth inhibitory effect.

[0108] On the other hand, in Example 1, where the zinc oxide (ZnO) content is 0.1 mol% relative to 100 mol% of the main component of the base material, densification occurs by firing at 1,120°C, even though the firing temperature is about 20°C lower, demonstrating a clear grain growth inhibition effect.

[0109] On the other hand, in Comparative Example 2, where the zinc oxide (ZnO) content is 0.4 mol% relative to 100 mol% of the main component of the base material, densification occurs by firing at 1,120°C, even though the firing temperature is about 20°C lower. While this clearly inhibits grain growth, there are reliability issues, as will be discussed later.

[0110] Figures 4(a) and (b) are graphs showing the results of reliability tests conducted under harsh conditions for examples and comparative examples of one embodiment of the present invention.

[0111] Figure 4(a) shows the case of Example 1 of the present invention, in which the zinc oxide (ZnO) content is 0.1 mol% relative to 100 mol% of the main component of the base material, and it can be confirmed that there are no defects in reliability tests conducted under harsh conditions, and that it has excellent reliability.

[0112] Figure 4(b) shows the case of Comparative Example 2, in which the zinc oxide (ZnO) content is 0.4 mol% relative to 100 mol% of the main component of the base material. In this case, a large number of defects occurred in the reliability test evaluation conducted under harsh conditions, confirming a decrease in reliability.

[0113] Although embodiments of the present invention have been described in detail above, it will be clear to those with ordinary skill in the art that the scope of the present invention is not limited thereto, and that various modifications and variations are possible within the scope of the technical idea of ​​the present invention as described in the claims. [Explanation of symbols]

[0114] 110 Ceramic body 111 Dielectric layer 121, 122 First and second internal electrodes 131, 132 First and second external electrodes

Claims

1. BaTiO ３ 、(Ba １－ｘ Ca ｘ )(Ti １－ｙ Ca ｙ )O ３ (where x is 0 ≤ x ≤ 0.3, y is 0 ≤ y ≤ 0.1), (Ba １－ｘ Ca ｘ )(Ti １－ｙ Zr ｙ )O ３ (where x is 0 ≤ x ≤ 0.3, y is 0 ≤ y ≤ 0.5), and Ba(Ti １－ｙ Zr ｙ )O ３ (where 0 < y ≤ 0.5), containing one or more selected from the group consisting of BaTiO ３ system base material main components and sub-components, the sub-components including zinc oxide (ZnO) as the first sub-component, The zinc oxide (ZnO) content is 0.1 moles or more and less than 0.4 moles per 100 moles of the main component of the base material. It does not contain any minor components made of Al. The dielectric ceramic composition wherein the aforementioned minor component contains magnesium (Mg) as a second minor component, and the total content of zinc oxide (ZnO) and magnesium (Mg) is less than 0.8 moles per 100 moles of the main component of the base material.

2. The dielectric ceramic composition according to claim 1, wherein the first minor component further comprises an oxide containing at least one of Mn, V, Cr, Fe, Ni, Co, and Cu, and the content of the first minor component is 0.1 to 2.0 moles per 100 moles of the main component of the base material.

3. The dielectric ceramic composition according to claim 1 or 2, wherein the dielectric ceramic composition contains 0.001 to 0.5 moles of a third minor component, which is an oxide containing Si or a glass compound containing Si, per 100 moles of the main component of the base material.

4. The dielectric ceramic composition according to any one of claims 1 to 3, wherein the dielectric ceramic composition contains 0.001 to 4.0 moles of a fourth minor component, which is an oxide containing at least one of Dy, Y, Ho, Er, Ce, Nd, Pm, Eu, Gd, Tm, Yb, Lu, and Sm, per 100 moles of the main component of the base material.

5. A ceramic body including a dielectric layer, and a first internal electrode and a second internal electrode arranged to face each other with the dielectric layer in between, The ceramic body includes a first external electrode disposed on the outside of the ceramic body and electrically connected to the first internal electrode, and a second external electrode electrically connected to the second internal electrode, The dielectric layer comprises dielectric grains containing a dielectric ceramic composition, The dielectric ceramic composition is BaTiO ３ , (Ba １－ｘ Ca ｘ ) (Ti １－ｙ Ca ｙ ) O ３ (Here, x is 0 ≤ x ≤ 0.3, y is 0 ≤ y ≤ 0.1), (Ba １－ｘ Ca ｘ ) (Ti １－ｙ Zr ｙ ) O ３ (where x is 0 ≤ x ≤ 0.3, y is 0 ≤ y ≤ 0.5), and Ba(Ti １－ｙ Zr ｙ ) O ３ (Here, BaTiO contains one or more selected from the group consisting of 0 < y ≤ 0.5) ３ The system contains a main component and a minor component, the minor component of which includes zinc oxide (ZnO) as the first minor component. The zinc oxide (ZnO) content is 0.1 moles or more and less than 0.4 moles per 100 moles of the main component of the base material. A multilayer ceramic capacitor that does not contain aluminum as a minor component.

6. The multilayer ceramic capacitor according to claim 5, wherein the aforementioned minor component includes magnesium (Mg) as a second minor component, and the total content of zinc oxide (ZnO) and magnesium (Mg) is less than 0.8 moles per 100 moles of the main component of the base material.

7. The multilayer ceramic capacitor according to claim 5 or 6, wherein the first minor component further comprises an oxide containing at least one of Mn, V, Cr, Fe, Ni, Co, and Cu, and the content of the first minor component is 0.1 to 2.0 moles per 100 moles of the main component of the base material.

8. The dielectric ceramic composition comprises 0.001 to 0.5 moles of a third minor component, which is a Si-containing oxide or a Si-containing glass compound, per 100 moles of the main component of the base material, in the multilayer ceramic capacitor according to any one of claims 5 to 7.

9. The dielectric ceramic composition comprises 0.001 to 4.0 moles of a fourth minor component, which is an oxide containing at least one of Dy, Y, Ho, Er, Ce, Nd, Pm, Eu, Gd, Tm, Yb, Lu, La, and Sm, per 100 moles of the main component of the base material, in the multilayer ceramic capacitor according to any one of claims 5 to 8.

10. The multilayer ceramic capacitor according to claim 9, wherein the lanthanum (La) is arranged at the grain boundaries of the dielectric grain.

11. The multilayer ceramic capacitor according to any one of claims 5 to 10, wherein the thickness of the dielectric layer is 0.4 μm or less.

12. The multilayer ceramic capacitor according to any one of claims 5 to 11, wherein the thickness of the first internal electrode and the second internal electrode is 0.4 μm or less.

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