Ceramic electronic components

Abstract

To provide a ceramic electronic component.SOLUTION: A ceramic electronic component according to an embodiment of the present invention includes a main body including a dielectric layer and an internal electrode, and an external electrode placed on the main body and connected to the internal electrode, and the dielectric layer contains a plurality of dielectric crystal grains, at least one of the plurality of dielectric crystal grains has a core-double shell structure, and the double shell includes a first shell surrounding at least a part of the core, and a second shell surrounding at least a part of the first shell, and the first shell includes a first element which is one or more of Sn, Sb, Ge, Si, Ga, In, and Zr, and the second shell includes a second element which is one or more of Ca and Sr.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] This invention relates to ceramic electronic components. [Background technology]

[0002] Typically, ceramic electronic components that use 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] A multilayer ceramic capacitor (MLCC), a type of ceramic electronic component, is a chip-type capacitor that is mounted on the printed circuit boards of various electronic products such as liquid crystal displays (LCDs) and plasma display panels (PDPs), computers, smartphones, and mobile phones, and plays the role of charging or discharging electricity.

[0004] Such multilayer ceramic capacitors have the advantages of being small, yet guaranteeing high capacitance, and being easy to mount, making them suitable for use as components in various electronic devices. With the miniaturization and increased power output of various electronic devices such as computers and mobile devices, the demand for smaller and higher-capacitance multilayer ceramic capacitors is increasing.

[0005] To achieve miniaturization and higher capacitance in multilayer ceramic capacitors, it is necessary to reduce the thickness of the dielectric layer and internal electrodes and increase the number of layers. Currently, the thickness of the dielectric layer has reached approximately 0.6 μm, and thinning is progressing.

[0006] In order to achieve thinning of a dielectric layer, a technique for suppressing basic charge transfer is basically required by reducing dielectric crystal grains and increasing the grain boundary resistance of the dielectric crystal grains.

[0007] In order to increase the grain boundary resistance of dielectric crystal grains, a method of doping an impurity element into BaTiO3 is usually employed, but such a method may cause a decrease in dielectric properties compared with pure BaTiO3. Summary of the Invention Problem to be Solved by the Invention

[0008] One of the various objects of the present invention is to provide a ceramic electronic component capable of improving reliability.

[0009] One of the various objects of the present invention is to provide a ceramic electronic component having an improved dielectric constant.

[0010] However, the object of the present invention is not limited to the above description, and can be more easily understood in the process of describing specific embodiments of the present invention. Means for Solving the Problem

[0011] A ceramic electronic component according to an embodiment of the present invention is a ceramic electronic component including a main body containing a dielectric layer and an internal electrode, and an external electrode disposed on the main body and connected to the internal electrode, wherein the dielectric layer contains a plurality of dielectric crystal grains, at least one or more of the plurality of dielectric crystal grains has a core-double shell structure, the double shell includes a first shell surrounding at least a part of the core, and a second shell surrounding at least a part of the first shell, the first shell contains a first element that is one or more selected from the group consisting of Sn, Sb, Ge, Si, Ga, In, and Zr, and the second shell contains a second element that is one or more selected from the group consisting of Ca and Sr. Effect of the Invention

[0012] As one of the various effects of the present invention, since at least one or more of the plurality of dielectric crystal grains has a core-double shell structure, the reliability of a ceramic electronic component can be improved.

[0013] As one of the various effects of the present invention, in the core-double shell structure, a high dielectric constant and / or high reliability can be ensured by causing a first shell to contain a first element that is at least one selected from the group consisting of Sn, Sb, Ge, Si, Ga, In, and Zr, and causing a second shell to contain a second element that is at least one selected from the group consisting of Ca and Sr.

[0014] However, the various and beneficial advantages and effects of the present invention are not limited to the above description, and can be more easily understood in the process of describing specific embodiments of the present invention. [[BRIEF DESCRIPTION OF THE DRAWINGS]]

[0015] [Figure 1] This is a schematic perspective view of a ceramic electronic component according to an embodiment of the present invention. [Figure 2] This is a schematic cross-sectional view taken along line I-I' in FIG. 1. [Figure 3] This is a schematic cross-sectional view taken along line II-II' in FIG. 1. [Figure 4] This is an exploded perspective view schematically showing an exploded main body in which dielectric layers and internal electrodes according to an embodiment of the present invention are laminated. [Figure 5] This is an enlarged view of region P in FIG. 2. [Figure 6] This is a schematic diagram showing a crystal grain having a core-double shell structure. [Figure 7] This is an image obtained by scanning a cross-section of a dielectric layer according to an embodiment of the present invention with a transmission electron microscope. [Figure 8] This is an image obtained by scanning a cross-section of a dielectric layer according to an embodiment of the present invention with a transmission electron microscope. [Figure 9] These are the results of TEM-EDS line analysis for a crystal grain having a core-double shell of Test No. 4. [Figure 10] This is the result of TEM-EDS line analysis for the core-double shell crystal grains in test number 2. [Figure 11] This is the result of TEM-EDS line analysis for the core-double shell crystal grain of test number 5. [Figure 12] This is the result of TEM-EDS line analysis for the core-double shell crystal grain of test number 9. [Figure 13] This is the result of TEM-EDS line analysis for core-double shell crystal grains from test number 10. [Figure 14] This is the result of TEM-EDS line analysis for the core-double shell crystal grain of test number 8. [Figure 15] This graph shows the dielectric constant with temperature for test numbers 1, 6, and 11. [Figure 16] The images show (a) a TEM scan of the dielectric layer of test number 9, (b) a mapping image for the element Sn, (c) a mapping image for the element Sr, and (d) a composite image of (b) and (c) superimposed. [Modes for carrying out the invention]

[0016] Preferred embodiments of the present invention will be described below with reference to the attached drawings. However, embodiments of the present invention can be modified into various 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.

[0017] In order to clearly explain the present invention, parts unrelated to the explanation have been omitted from the drawings, and the dimensions and thicknesses of each component shown in the drawings are arbitrarily shown for the convenience of explanation, and the present invention is not necessarily limited to those shown. Furthermore, components that have the same function within the scope of the same concept will be described using the same reference numerals. Moreover, throughout the specification, when a component is "included," unless otherwise stated, it does not mean that other components are excluded, but rather that other components may be further included.

[0018] In drawings, the first direction can be defined as the lamination direction or thickness (T) direction, the second direction as the length (L) direction, and the third direction as the width (W) direction.

[0019] Ceramic electronic components Figure 1 is a schematic perspective view of a ceramic electronic component according to one embodiment of the present invention; Figure 2 is a schematic cross-sectional view along line I-I' in Figure 1; Figure 3 is a schematic cross-sectional view along line II-II' in Figure 1; Figure 4 is an exploded perspective view of a body with a dielectric layer and internal electrodes stacked according to one embodiment of the present invention; Figure 5 is an enlarged view of region P in Figure 2; and Figure 6 is a schematic diagram showing crystal grains having a core-double shell structure.

[0020] The following describes in detail a ceramic electronic component 100 according to one embodiment of the present invention with reference to Figures 1 to 6. While a multilayer ceramic capacitor will be described as an example of a ceramic electronic component, the present invention is not limited to this and can be applied to various ceramic electronic components using ceramic materials, such as inductors, piezoelectric elements, varistors, or thermistors.

[0021] A ceramic electronic component 100 according to one embodiment of the present invention is a ceramic electronic component comprising a body 110 including a dielectric layer 111 and internal electrodes 121, 122, and external electrodes 131, 132 disposed on the body and connected to the internal electrodes, wherein the dielectric layer comprises a plurality of dielectric crystal grains 10a, 10b, 10c, and at least one of the plurality of dielectric crystal grains has a core-double shell structure, the double shell comprises a first shell S1 surrounding at least a part of the core C, and a second shell S2 surrounding at least a part of the first shell, the first shell comprises one or more first elements which are Sn, Sb, Ge, Si, Ga, In, and Zr, and the second shell comprises one or more second elements which are Ca and Sr.

[0022] The main body 110 can have dielectric layers 111 and internal electrodes 121 and 122 stacked alternately.

[0023] The specific shape of the main body 110 is not particularly limited, but as shown in the figure, the main body 110 may be a hexahedron or a similar shape. Furthermore, due to the shrinkage of the ceramic powder contained in the main body 110 during the firing process, the main body 110 may not be a perfectly straight hexahedron, but may have a substantially hexahedron shape.

[0024] The main body 110 may have first and second surfaces 1 and 2 facing each other in a first direction, third and fourth surfaces 3 and 4 connected to the first and second surfaces 1 and 2 and facing each other in a second direction, and fifth and sixth surfaces 5 and 6 connected to the first and second surfaces 1 and 2 and connected to the third and fourth surfaces 3 and 4 and facing each other in a third direction.

[0025] The multiple dielectric layers 111 that make up the main body 110 are in a fired state, and the boundaries between adjacent dielectric layers 111 can be integrated to such an extent that they are difficult to confirm without using a scanning electron microscope (SEM).

[0026] Referring to Figure 5, the dielectric layer 111 includes a plurality of dielectric crystal grains 10a, 10b, and 10c, and at least one of the plurality of dielectric crystal grains is a dielectric crystal grain 10a having a core-double shell structure.

[0027] Referring to Figure 6, the dielectric crystal grain 10a having a core-double shell structure includes a first shell S1 surrounding at least a portion of the core C, and a second shell S2 surrounding at least a portion of the first shell S1.

[0028] Multilayer ceramic capacitors (MLCCs), a type of ceramic electronic component, are trending towards higher capacitance and thinner layers. To achieve thinner dielectric layers, it is fundamentally necessary to reduce the size of the dielectric crystal grains and increase the grain boundary resistance of the dielectric crystal grains, thereby suppressing basic charge transfer. To increase the grain boundary resistance of the dielectric crystal grains, a method of doping BaTiO3 with impurity elements is usually used.

[0029] However, the above method may result in reduced dielectric properties compared to pure BaTiO3, and there are still problems with its effectiveness when the dielectric layer is made ultrathin to achieve a larger capacitance, or when the operating environment becomes more severe and involves higher voltages.

[0030] Therefore, in the present invention, at least one of the plurality of dielectric crystal grains has a core-double shell structure, and the double shell includes a first shell S1 surrounding at least a part of the core C and a second shell S2 surrounding at least a part of the first shell, and the first shell contains one or more first elements from Sn, Sb, Ge, Si, Ga, In, and Zr, and the second shell contains one or more second elements from Ca and Sr, thereby improving reliability, dielectric properties, etc.

[0031] Core C plays a role in maintaining the dielectric constant. Core C may contain no first or second elements, or only trace amounts. Therefore, core C can be pure BaTiO3 free of impurities, and core C can contain BaTiO3. Generally, pure BaTiO3 can have a higher dielectric constant than BaTiO3 doped with impurity elements.

[0032] The first shell S1 contains one or more first elements, which are selected from Sn, Sb, Ge, Si, Ga, In, and Zr. The first elements contained in the first shell S1 dope the B-site of BaTiO3, increasing the band gap energy that allows other rare earth elements and doped elements to diffuse into the crystal grains. This allows the first shell S1 to act as a barrier, suppressing the diffusion of other rare earth elements and doped elements into the crystal grains. Furthermore, the first shell S1 can suppress the growth of dielectric crystal grains and contribute to the finer grain size of the dielectric crystal grains.

[0033] The first shell can contain Ba(Ti,Sn)O3 because the first element, Sn, contained in the first shell S1, is doped into the B-site of BaTiO3.

[0034] The second element, which is one or more of Ca and Sr, contained in the second shell S2, dops the A-site of BaTiO3 and plays a role in improving reliability and / or dielectric constant. Of the second elements, Ca can have a greater effect on improving reliability, while Sr can have a greater effect on improving dielectric constant.

[0035] The second shell S2 can contain one or more of (Ba,Ca)TiO3 and (Ba,Sr)TiO3 by doping the A-site of the second element, which is one or more of Ca and Sr, into the second shell S2.

[0036] Furthermore, because the concentration of the first element changes abruptly at the boundary between core C and the first shell S1, and the concentration of the second element changes abruptly at the boundary between the first shell S1 and the second shell S2, core C, the first shell S1, and the second shell S2 can be easily distinguished and confirmed by TEM-EDS analysis.

[0037] Specifically, in cross-sections cut in the first and second directions at the center of the third direction of the main body, EDS (Energy Disperse X-Ray Spectrometer) line analysis was performed on the dielectric crystal grains of the dielectric layer located at the center of the first and second directions using a Transmission Electron Microscope (TEM). In this process, when analyzing from the center α of the dielectric crystal grain toward the outside of the dielectric crystal grain, the region where the concentration of the first element begins to increase rapidly is defined as the boundary between the core C and the first shell S1, and the region where the concentration of the second element begins to increase rapidly is defined as the boundary between the first shell S1 and the second shell S2, thereby allowing the core C, the first shell S1, and the second shell S2 to be distinguished.

[0038] As shown in Figures 5 and 6, the first shell S1 can be positioned to cover the entire surface of the core C, and the second shell S2 can be positioned to cover the entire surface of the first shell S1. However, the first shell does not have to cover a portion of the core's surface, and the second shell may exist in a form that does not cover a portion of the first shell's surface.

[0039] In this case, the first shell S1 can be arranged to cover 90% or more of the surface area of ​​the core, and the second shell S2 can be arranged to cover 90% or more of the surface area of ​​the first shell S1. This is because if the first shell S1 is arranged to cover less than 90% of the surface area of ​​the core, or if the second shell S2 is arranged to cover less than 90% of the surface area of ​​the first shell S1, the reliability improvement effect according to the present invention may not be sufficient.

[0040] In one embodiment, the concentrations of the first element in the core C, the first shell S1, and the second shell S2 are set to C1C , C1 S1 , C1 S2 , and let the concentrations of the second element in core C, first shell S1, and second shell S2 be C2 C , C2 S1 , C2 S2 respectively, then C1 S1 is higher than C1 S2 and C1 C , and C2 S2 can be higher than C2 C and C2 S1 . That is, core C, first shell S1, and second shell S2 can be distinguished by changes in the concentrations of the first element and the second element.

[0041] Furthermore, since substantially no first element and second element are present in core C, and substantially no second element is present in first shell S1, the above C1 C satisfies 0.01*C1 S1 or less, and the above C2 C and C2 S1 can satisfy 0.01*C2 S2 or less.

[0042] In one embodiment, the atomic ratio of said C2 S2 to C1 S1 , which is C2 S2 / C1 S1 can be 0.1 or more and 1.0 or less.

[0043] C2 S2 / C1 S1 If it is less than 0.1, effects such as the improvement of dielectric constant and the improvement of reliability may be insufficient. On the other hand, when the content of the first element is extremely small and C2 S2 / C1 S1 exceeds 1.0, the effect of suppressing diffusion of other rare earth elements and doping elements in the first shell into the interior of crystal grains may become insufficient, making it difficult to achieve a core-double shell structure.

[0044] In one embodiment, the second element is Ca, and said C2 S2 and C1 S1The atomic ratio of C2 S2 / C1 S1 This value can be between 0.55 and 1.0. This allows the reliability improvement effect of the core-dual shell structure to become more pronounced.

[0045] In one embodiment, the second element is Sr, and the C2 S2 and C1 S1 The atomic ratio of C2 S2 / C1 S1 This can be between 0.53 and 1.0. This allows the dielectric constant improvement effect of the core-double shell structure to become more pronounced.

[0046] On the other hand, the content of the first and second elements is not particularly limited. For example, the content of the first element contained in the first shell may be 0.5 to 5 mol% based on the entire core-double shell structure, and the content of the second element contained in the second shell may be 0.5 to 5 mol% based on the entire core-double shell structure.

[0047] Specifically, if the content of the second element in the second shell is less than 0.5 mol% relative to the entire core-double shell structure, the reliability and dielectric constant improvement effect of the core-double shell structure will be insufficient. If it exceeds 5 mol%, the second element will segregate and precipitate in the form of an oxide, which may actually decrease reliability. On the other hand, the content of the first element in the first shell can be adjusted considering the effect of suppressing the diffusion of other rare earth elements and doped elements in the first shell into the interior of the crystal grains, and the content of the second element in the second shell.

[0048] In one embodiment, when the length of the first shell S1 measured along the long axis passing through the center α of the core-double shell structure is defined as LS1, and the length of the second shell S2 is defined as LS2, then LS2 / LS1 can be between 0.1 and 1.

[0049] If LS2 / LS1 is less than 0.1, the effects of improving dielectric constant and reliability may be insufficient. On the other hand, if the amount of the first element is very small and LS2 / LS1 exceeds 1.0, the effect of suppressing the diffusion of other rare earth elements and doping elements into the interior of the crystal grains of the first shell S1 may be insufficient, making it difficult to realize a core-double shell structure.

[0050] In one embodiment, the second element is Ca, and the LS2 / LS1 ratio can be between 0.43 and 1. This allows the reliability improvement effect of the core-double shell structure to become more pronounced.

[0051] In one embodiment, the first element is Sr, and the LS2 can be between 0.38 and 1. This allows the dielectric constant improvement effect of the core-double shell structure to become more pronounced.

[0052] In one embodiment, LS1 can be 4 to 100 nm.

[0053] If LS1 is less than 4 nm, the grain growth inhibition effect and the effect of suppressing the diffusion of other rare earth elements and doping elements into the grain of the first shell S1 may be insufficient. Conversely, if LS1 exceeds 100 nm, the dielectric properties may decrease.

[0054] In one embodiment, LS2 can be 2 to 60 nm.

[0055] If LS2 is less than 2 nm, the effects of improving dielectric constant and reliability are insufficient. If it exceeds 60 nm, the second element segregates and precipitates in the form of an oxide, which may actually decrease reliability.

[0056] In one embodiment, when the length of the core measured along the long axis passing through the center of the core-double shell structure is denoted as LC, LC can be 10 to 200 nm.

[0057] On the other hand, there is no particular limitation on the manufacturing method for realizing dielectric crystal grains with a core-double shell structure.

[0058] For example, first, BaTiO3, which corresponds to the core C, can be synthesized in a primary manner using a hydrothermal synthesis method. Next, after adding SnO2 in the secondary synthesis process and then growing the grains, a first shell S1 containing a high concentration of Sn can be formed. Then, in the tertiary synthesis process, after adding one or more of Ca and Sr and then growing the grains, a dielectric powder can be obtained in which a second shell S2 containing one or more of Ca and Sr in high concentrations has been formed. Subsequently, a dielectric layer can be formed using a dielectric composition obtained by adding various additives, organic solvents, binders, dispersants, etc., to the above dielectric powder.

[0059] Referring to Figure 5, the dielectric layer 111 can include dielectric crystal grains 10b having a core-shell structure, in addition to dielectric crystal grains 10a having a core-double-shell structure. Therefore, at least one of the plurality of dielectric crystal grains can be dielectric crystal grains 10b having a core-shell structure. A dielectric crystal grain 10b having a core-shell structure can include a core 10b1 and a shell 10b2 surrounding at least a portion of the core 10b1.

[0060] Furthermore, the dielectric layer 111 may also contain dielectric crystal grains 10c that do not have another shell.

[0061] In this case, among the multiple dielectric crystal grains 10a, 10b, and 10c, the number of dielectric crystal grains 10a having the core-double shell structure described above can be 50% or more. Here, the proportion of dielectric crystal grains having the core-double shell structure can be measured from an image obtained by scanning the cross-section of the dielectric layer with a transmission electron microscope (TEM).

[0062] If the number of dielectric crystal grains having the above-described core-double-shell structure is less than 50% of the multiple dielectric crystal grains, the reliability and dielectric constant improvement effect may be insufficient.

[0063] On the other hand, there is no particular limit to the size of the dielectric crystal grains. For example, the average grain size of the dielectric crystal grains can be between 50 nm and 300 nm.

[0064] If the average grain size is less than 50 nm, achieving capacitance becomes difficult due to a decrease in dielectric constant. If it exceeds 300 nm, the rate of change in capacitance due to temperature and DC voltage may increase, and reliability may decrease due to a decrease in the number of dielectric grains per dielectric layer.

[0065] The main body 110 may include a capacitance forming portion Ac which is disposed inside the main body 110 and includes a first internal electrode 121 and a second internal electrode 122 which are arranged facing each other with a dielectric layer 111 in between, and cover portions 112 and 113 which are formed on the upper and lower parts of the capacitance forming portion Ac in a first direction.

[0066] Furthermore, the capacitance-forming portion Ac is a part that contributes to the capacitance formation of the capacitor, and can be formed by repeatedly stacking multiple first and second internal electrodes 121 and 122 with a dielectric layer 111 in between.

[0067] The cover portions 112 and 113 may include an upper cover portion 112 positioned above the volume forming portion Ac in the first direction, and a lower cover portion 113 positioned below the volume forming portion Ac in the first direction.

[0068] The upper cover portion 112 and the lower cover portion 113 described above can be formed by stacking a single dielectric layer or two or more dielectric layers on the upper and lower surfaces of the capacitance forming portion Ac in the thickness direction (first direction), and basically serve to prevent damage to the internal electrodes due to physical or chemical stress.

[0069] The upper cover portion 112 and the lower cover portion 113 described above do not include internal electrodes and may contain the same material as the dielectric layer 111.

[0070] In other words, the upper cover portion 112 and the lower cover portion 113 can include ceramic materials, for example, barium titanate (BaTiO3) based ceramic materials.

[0071] On the other hand, the thickness of the cover portions 112 and 113 is not particularly limited. However, in order to more easily achieve miniaturization and high capacitance of the stacked electronic component, the thickness tp of the cover portions 112 and 113 can be 20 μm or less.

[0072] Furthermore, margin portions 114 and 115 can be arranged on the side surface of the volume-forming portion Ac.

[0073] The margin portions 114 and 115 may include a margin portion 114 located on the fifth surface 5 of the main body 110 and a margin portion 115 located on the sixth surface 6. That is, the margin portions 114 and 115 can be located on both sides of the ceramic main body 110 in the width direction (third direction).

[0074] As shown in Figure 3, the margin portions 114 and 115 can refer to the regions between the interface between both ends of the first and second internal electrodes 121 and 122 and the body 110 in a cross-section obtained by cutting the main body 110 in the width-thickness (WT) direction.

[0075] The margins 114 and 115 essentially serve to prevent damage to the internal electrodes due to physical or chemical stress.

[0076] The margin portions 114 and 115 can be formed by applying a conductive paste to the ceramic green sheet, excluding the areas where the margin portions are formed, to form internal electrodes.

[0077] Furthermore, in order to suppress the step caused by the internal electrodes 121 and 122, after lamination the internal electrodes are cut so that they are exposed on the fifth and sixth surfaces 5 and 6 of the main body, and then a single dielectric layer or two or more dielectric layers may be laminated on both sides of the capacitance forming portion Ac in the width direction (third direction) to form margin portions 114 and 115.

[0078] On the other hand, the thickness td of the dielectric layer 111 does not need to be particularly limited.

[0079] However, generally speaking, when the dielectric layer is formed to a thickness of less than 0.6 μm, especially when the thickness of the dielectric layer is 0.55 μm or less, there was a risk of reduced reliability.

[0080] As described above, by including dielectric crystal grains 10a with a core-double shell structure in the dielectric layer 111, effects such as improved dielectric constant and improved reliability can be ensured. Therefore, even when the thickness td of the dielectric layer 111 is 0.55 μm or less, excellent reliability can be ensured.

[0081] Therefore, the reliability improvement effect according to the present invention can be more pronounced when the thickness td of the dielectric layer 111 is 0.55 μm or less.

[0082] The thickness td of the dielectric layer 111 can represent the average thickness of the dielectric layer 111 that is placed between the first internal electrode 121 and the second internal electrode 122.

[0083] The average thickness of the dielectric layer 111 can be measured by scanning the cross-section of the main body 110 in the length and thickness direction (LT) using a scanning electron microscope (SEM).

[0084] For example, in an arbitrary dielectric layer extracted from images obtained by scanning the cross-sections in the first and second directions (length and thickness directions) of the main body 110, which has been cut in the center of the third direction (width direction), using a scanning electron microscope (SEM), the thickness can be measured at 30 equally spaced points in the length direction, and the average value can be measured.

[0085] The thickness measured at the 30 equally spaced points mentioned above can be measured in the capacitance forming region Ac, which represents the area where the first and second internal electrodes 121 and 122 overlap each other.

[0086] The internal electrodes 121 and 122 can be stacked alternately with the dielectric layer 111.

[0087] The internal electrodes 121 and 122 may include first and second internal electrodes 121 and 122. The first and second internal electrodes 121 and 122 are arranged alternately facing each other with the dielectric layer 111 constituting the main body 110 in between, and can be exposed on the third and fourth surfaces 3 and 4 of the main body 110, respectively.

[0088] Referring to Figure 2, the first internal electrode 121 can be exposed via the third surface 3, separated from the fourth surface 4, and the second internal electrode 122 can be exposed via the fourth surface 4, separated from the third surface 3.

[0089] In this case, the first and second internal electrodes 121 and 122 can be electrically isolated from each other by the dielectric layer 111 placed between them.

[0090] Referring to Figure 4, the main body 110 can be formed by alternately stacking ceramic green sheets printed with the first internal electrode 121 and ceramic green sheets printed with the second internal electrode 122, and then firing them.

[0091] The materials used to form the internal electrodes 121 and 122 are not particularly limited, and any material with excellent electrical conductivity can be used. For example, the internal electrodes 121 and 122 may include one or more of the following: nickel (Ni), copper (Cu), palladium (Pd), silver (Ag), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), and alloys thereof.

[0092] Furthermore, the internal electrodes 121 and 122 can be formed by printing a conductive paste for internal electrodes containing one or more of the following on a ceramic green sheet: nickel (Ni), copper (Cu), palladium (Pd), silver (Ag), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), and alloys thereof. While screen printing or gravure printing can be used as the printing method for the conductive paste for internal electrodes, the present invention is not limited to these methods.

[0093] On the other hand, the thickness te of the internal electrodes 121 and 122 does not need to be particularly limited.

[0094] However, generally speaking, when the internal electrode is formed to a thickness of less than 0.6 μm, especially when the thickness of the internal electrode is 0.55 μm or less, there was a risk of reduced reliability.

[0095] As described above, by including dielectric crystal grains 10a with a core-double shell structure in the dielectric layer 111, effects such as improved dielectric constant and improved reliability can be ensured, and excellent reliability can be ensured even when the thickness te of the internal electrodes 121 and 122 is 0.55 μm or less.

[0096] Therefore, when the thickness te of the internal electrodes 121 and 122 is 0.55 μm or less, the effects of the present invention can be made more pronounced, and miniaturization and increased capacitance of the stacked electronic component can be achieved more easily.

[0097] The thickness te of the internal electrodes 121 and 122 can be said to represent the average thickness of the internal electrodes 121 and 122.

[0098] The average thickness of the internal electrodes 121 and 122 can be measured by scanning the cross-section of the main body 110 in the length and thickness direction (LT) using a scanning electron microscope (SEM).

[0099] For example, the thickness of arbitrary first and second internal electrodes 121 and 122 extracted from images obtained by scanning the first and second cross-sections (length and thickness directions) of the main body 110, which have been cut in the center of the third direction (width direction), at 30 equally spaced points in the length direction, can be measured, and the average value can be calculated.

[0100] The 30 equally spaced points mentioned above can be measured in the capacitance forming region Ac, which represents the area where the internal electrodes 121 and 122 overlap each other.

[0101] External electrodes 131 and 132 can be arranged on the third surface 3 and fourth surface 4 of the main body 110.

[0102] The external electrodes 131 and 132 are arranged on the third and fourth surfaces 3 and 4 of the main body 110, respectively, and may include first and second external electrodes 131 and 132 that are connected to first and second internal electrodes 121 and 122, respectively.

[0103] Referring to Figure 1, the external electrodes 131 and 132 can be arranged to cover both end faces of the side margin portions 114 and 115 in the second direction.

[0104] In this embodiment, a structure is described in which the stacked electronic component 100 has two external electrodes 131 and 132. However, the number and shape of the external electrodes 131 and 132 may vary depending on the form of the internal electrodes 121 and 122 and other purposes.

[0105] On the other hand, the external electrodes 131 and 132 can be formed using any material that has electrical conductivity, such as metal, and the specific material can be determined by considering electrical properties, structural stability, etc. Furthermore, they can have a multilayer structure.

[0106] For example, the external electrodes 131 and 132 may include electrode layers 131a and 132a placed on the main body 110, and plating layers 131b and 132b formed on the electrode layers 131a and 132a.

[0107] More specific examples of electrode layers 131a and 132a include the fact that electrode layers 131a and 132a may be firing electrodes containing conductive metal and glass, or resin-based electrodes containing conductive metal and resin.

[0108] Furthermore, the electrode layers 131a and 132a may be formed in a manner in which a fired electrode and a resin-based electrode are formed sequentially on the main body. Also, the electrode layers 131a and 132a may be formed by transferring a sheet containing a conductive metal onto the main body, or by transferring a sheet containing a conductive metal onto a fired electrode.

[0109] The conductive metal contained in the electrode layers 131a and 132a can be any material with excellent electrical conductivity, but is not particularly limited. For example, the conductive metal can be one or more of nickel (Ni), copper (Cu), and alloys thereof.

[0110] The plating layers 131b and 132b play a role in improving mounting characteristics. The types of plating layers 131b and 132b are not particularly limited and can be plating layers containing one or more of Ni, Sn, Pd, and their alloys, and may be formed in multiple layers.

[0111] More specific examples of the plating layers 131b and 132b include the fact that the plating layers 131b and 132b can be Ni plating layers or Sn plating layers, and may be formed in a configuration in which a Ni plating layer and an Sn plating layer are formed sequentially on the electrode layers 131a and 132a, or in a configuration in which an Sn plating layer, a Ni plating layer, and an Sn plating layer are formed sequentially. Furthermore, the plating layers 131b and 132b may include multiple Ni plating layers and / or multiple Sn plating layers.

[0112] There is no particular limit to the size of the stacked electronic component 100.

[0113] However, in order to achieve both miniaturization and high capacitance, it is necessary to reduce the thickness of the dielectric layer and internal electrodes and increase the number of layers. Therefore, the reliability and insulation resistance improvement effects of the present invention can be more pronounced in a multilayer electronic component 100 having a size of 0402 (length × width, 0.4 mm × 0.2 mm) or less.

[0114] Therefore, considering manufacturing tolerances, the size of external electrodes, etc., the reliability improvement effect according to the present invention can be more pronounced when the length of the stacked electronic component 100 is 0.44 mm or less and the width is 0.22 mm or less. Here, the length of the stacked electronic component 100 can mean the maximum size of the stacked electronic component 100 in the second direction, and the width of the stacked electronic component 100 can mean the maximum size of the stacked electronic component 100 in the third direction.

[0115] (Examples) First, BaTiO3, corresponding to the core C, was primarily synthesized using a hydrothermal synthesis method. Next, in the secondary synthesis process, SnO2 was added and then grain growth was carried out to form a first shell S1 containing a high concentration of Sn. In the tertiary synthesis process, a second element listed in Table 1 below was added and then grain growth was carried out to obtain a dielectric powder in which a second shell S2 containing one or more of Ca and Sr in high concentrations was formed. Subsequently, auxiliary components were added to the dielectric powder, mixed with dispersants using ethanol and toluene as solvents, and then a binder was added to fabricate a ceramic sheet. Ni electrodes were printed onto the molded ceramic sheet and laminated, then the chips were compressed, cut, calcined to remove the binder, and then fired to produce sample chips.

[0116] During the manufacturing of the dielectric powder, the content of SnO2 and the second element was varied for each test number, and in test number 11, BaTiO3 powder was used as the dielectric powder.

[0117] LC, LS1, LS2, and C2 of the core-double-shell structure dielectric crystal grains contained in the dielectric layers of test numbers 1-10 S2 / C1 S1 The dielectric constant was measured by TEM-EDS line analysis and is listed in Table 1 below. Furthermore, the dielectric constant and reliability of the manufactured sample chips were evaluated and are also listed in Table 1 below.

[0118] Each sample chip was cut in the first and second directions (thickness and length directions) at the center of the third direction (width direction). In the cross-sections obtained, the core-double-shell crystal grains contained in the dielectric layer located in the center of the first and second directions were analyzed using a transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS).

[0119] TEM-EDS line analysis was performed along the long axis passing through the center α of the core-double shell structure, and the intensity values ​​(counts) of the first element (Sn) and the second element (Ca or Sr) were measured. The boundary between the core C and the first shell S1 was defined as the point where the concentration of the first element begins to increase rapidly, and the boundary between the first shell S1 and the second shell S2 was defined as the point where the concentration of the second element begins to increase rapidly. The lengths of the region corresponding to the core C were defined as LC, the sum of the lengths on both sides corresponding to the first shell S1 was defined as LS1, and the sum of the lengths on both sides corresponding to the second shell S2 was defined as LS2, as shown in Table 1 below.

[0120] Furthermore, the average intensity values ​​(counts) of the first and second elements in core C are considered noise, and the value obtained by subtracting the average intensity values ​​(counts) of the first element in core C from the average intensity values ​​(counts) of the first element in the first shell S1 is C1. S1 Then, C2 is calculated by subtracting the average intensity value (counts) of the first element in the core C from the average intensity value (counts) of the second element in the second shell S2. S2 C2 S2 / C1 S1 The value was calculated.

[0121] The dielectric constant was evaluated by measuring the Temperature Coefficient of Capacitance (TCC). For each test number, the dielectric constant was measured for three sample chips while varying the temperature from -55°C to 150°C, and the value corresponding to 50°C was recorded.

[0122] Reliability was evaluated using severe reliability (HALT) testing. For each test number, 100 sample chips were subjected to a voltage 1.2 times the reference voltage (1Vr = 6.3V) at 150°C for 24 hours. Sample chips that short-circuited were deemed defective, and the defect rate was recorded.

[0123] [Table 1]

[0124] Tests 1 through 10 all contain dielectric crystal grains with a core-double shell structure, and it can be confirmed that they exhibit superior dielectric constant and reliability compared to test number 11.

[0125] Also, the second element is Ca, and C2 S2 / C1 S1 Test numbers 2-5, with a score of 0.55 or higher, demonstrate even greater reliability.

[0126] Also, the second element is Sr, and C2 S2 / C1 S1 Tests 6-9, with a dielectric constant of 0.53 or higher, demonstrate even greater superiority in dielectric properties.

[0127] Figures 7 and 8 are images obtained by scanning a cross-section of a dielectric layer according to one embodiment of the present invention with a transmission electron microscope.

[0128] The crystal grains in the areas circled in Figure 7 correspond to the dielectric crystal grains of the core-double shell structure. While it is difficult to distinguish the double shell in the images of Figures 7 and 8, referring to Figure 9, which shows the results of line analysis by EDS along the lines drawn in Figure 8, it can be confirmed that the core C, the first shell S1, and the second shell S2 are clearly distinguishable.

[0129] Furthermore, using this method, Figures 10 to 14, which show the results of line analysis by EDS for test numbers 2, 5, 8, 9, and 10, confirm that core C, the first shell S1, and the second shell S2 are clearly distinguishable.

[0130] Figure 15 is a graph showing the dielectric constant with temperature for test numbers 11, 1, and 6.

[0131] Referring to Figure 15, it can be seen that test samples 1 and 6, which have dielectric crystal grains with a core-double shell structure, have a higher dielectric constant compared to test sample 11, and the Curie temperature (Tc) at which the dielectric constant characteristics change also increases.

[0132] Figure 16 shows images of the dielectric layer of test number 9 scanned with a TEM (a), a mapping image for the Sn element (b), a mapping image for the Sr element (c), and a composite image (d) in which (b) and (c) are superimposed. It can be confirmed that the proportion of dielectric crystal grains having a core-double shell is 50% or more.

[0133] Although embodiments of the present invention have been described in detail above, the present invention is not limited by the embodiments described above and the accompanying drawings, but is limited by the claims attached. Therefore, within the scope of the technical idea of ​​the present invention as described in the claims, various forms of substitution, modification, and alteration are possible by persons with ordinary skill in the art, and these also fall within the scope of the present invention. [Explanation of Symbols]

[0134] 100 Ceramic Electronic Components 110 Main Unit 121, 122 Internal electrode 111 Dielectric layer 112, 113 Cover section 114, 115 Margin section 131, 132 External electrode

Claims

1. A main body including a dielectric layer and internal electrodes, A ceramic electronic component comprising an external electrode disposed on the main body and connected to the internal electrode, The dielectric layer comprises a plurality of dielectric crystal grains, and of the plurality of dielectric crystal grains, 50% or more have a core-double shell structure. The double shell includes a first shell surrounding at least a portion of the core, and a second shell surrounding at least a portion of the first shell. The first shell contains one or more first elements, which are Sn, Sb, Ge, Si, Ga, In, and Zr. The second shell is a ceramic electronic component containing one or more second elements, which are Ca and Sr.

2. The concentrations of the first element in the core, the first shell, and the second shell are C1, respectively. Ｃ , C1 Ｓ１ , C1 Ｓ２ The concentrations of the second element in the core, the first shell, and the second shell are set to C2, respectively. Ｃ , C2 Ｓ１ , C2 Ｓ２ In that case, C1 Ｓ１ is C1 Ｓ２ and C1 ｃ is higher than, and C2 Ｓ２ is C2 Ｃ and C2 Ｓ１ is higher than, the ceramic electronic component according to claim 1.

3. The C1 Ｃ is 0.01 * C1 Ｓ１ The following is true, C2 Ｃ and C2 Ｓ１ is 0.01 * C2 Ｓ２ The ceramic electronic component according to claim 2, which is as follows:

4. The aforementioned C2 Ｓ２ and C1 Ｓ１ The atomic ratio of C2 Ｓ２ / C1 Ｓ１ A ceramic electronic component according to claim 2 or 3, wherein the value is 0.1 or more and 1.0 or less.

5. The first element is Sn, and the second element is Ca, The aforementioned C2 Ｓ２ and C1 Ｓ１ The atomic ratio of C2 Ｓ２ / C1 Ｓ１ A ceramic electronic component according to any one of claims 2 to 4, wherein the ratio is 0.55 or more and 1.0 or less.

6. The first element is Sn, and the second element is Sr, The aforementioned C2 Ｓ２ and C1 Ｓ１ The atomic ratio of C2 Ｓ２ / C1 Ｓ１ A ceramic electronic component according to any one of claims 2 to 5, wherein the ratio is 0.53 or more and 1.0 or less.

7. A ceramic electronic component according to any one of claims 1 to 6, wherein when the length of the first shell measured along the long axis passing through the center of the core-double shell structure is denoted as LS1 and the length of the second shell as LS2, LS2 / LS1 is 0.1 or more and 1 or less.

8. The first element is Sn, and the second element is Ca, The ceramic electronic component according to claim 7, wherein the LS2 / LS1 ratio is 0.43 or more and 1 or less.

9. The first element is Sn, and the second element is Sr, The ceramic electronic component according to claim 7 or 8, wherein the LS2 is 0.38 or more and 1 or less.

10. The ceramic electronic component according to any one of claims 7 to 9, wherein the LS1 is 4 to 100 nm.

11. The ceramic electronic component according to any one of claims 7 to 10, wherein the LS2 is 2 to 60 nm.

12. The ceramic electronic component according to any one of claims 7 to 11, wherein the length of the core measured along the long axis passing through the center of the core-double shell structure is denoted as LC, and LC is 10 to 200 nm.

13. The aforementioned core is BaTiO ３ Includes, The first shell is Ba(Ti,Sn)O ３ Includes, The second shell is (Ba,Ca)TiO ３ and (Ba, Sr)TiO ３ A ceramic electronic component according to any one of claims 1 to 12, comprising one or more of the above.

14. The content of the first element contained in the first shell is 0.5 to 5 mol% based on the entire core-double shell structure. The ceramic electronic component according to any one of claims 1 to 13, wherein the content of the second element contained in the second shell is 0.5 to 5 mol% based on the entire core-double shell structure.

15. In the core-double shell structure, the first shell is arranged to cover 90% or more of the surface area of ​​the core. The ceramic electronic component according to any one of claims 1 to 14, wherein the second shell is arranged to cover 90% or more of the surface area of ​​the first shell.

16. The ceramic electronic component according to any one of claims 1 to 15, wherein at least one of the plurality of dielectric crystal grains has a core-shell structure.

17. The ceramic electronic component according to any one of claims 1 to 16, wherein the average crystal grain size of the dielectric crystal grains in the dielectric layer is 50 nm or more and 300 nm or less.

18. The ceramic electronic component according to any one of claims 1 to 17, wherein the average thickness of the dielectric layer is 0.55 μm or less.

19. The ceramic electronic component according to any one of claims 1 to 18, wherein the average thickness of the internal electrodes is 0.45 μm or less.

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