Multilayer electronic component

Abstract

The present disclosure provides a multilayer electronic component. The multilayer electronic component may include: a body including a dielectric layer and an internal electrode; and an external electrode disposed on the body, in which the dielectric layer may include a plurality of dielectric grains, at least one of the plurality of dielectric grains may have a core-shell structure including a core portion and a shell portion surrounding at least a portion of the core portion, a cross-section of the core portion may include a polygonal shape, and a cross-section of the shell portion may include a polygonal shape. The average length of the plurality of dielectric crystal grains may be greater than or equal to 80 nm and less than or equal to 200 nm, and the length of the core portion may be 70% or greater compared to the length of the corresponding dielectric crystal grains.

Description

[0001] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0091820 filed on July 14, 2023 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. Technical Field

[0002] The present disclosure relates to a multi-layer electronic assembly. Background Art

[0003] A multilayer ceramic capacitor (MLCC), a type of multilayer electronic component, may be a chip capacitor mounted on a printed circuit board of various types of electronic products such as an image display device (such as a liquid crystal display (LCD) or a plasma display panel (PDP)), a computer, a smart phone, a mobile phone, etc., for charging or discharging the same.

[0004] Such multilayer ceramic capacitors have a small size, achieve high capacitance, and are easily mounted on a printed circuit board, and thus can be used as components of various electronic devices. As various electronic devices such as computers and mobile devices have reduced sizes and high outputs, the demand for miniaturization and high capacitance of multilayer ceramic capacitors has increased.

[0005] Furthermore, in order to achieve miniaturization and high capacitance of multilayer electronic components, thin dielectric layers may be applied. However, as the dielectric layer becomes thinner, the insulation resistance value of the multilayer electronic component may decrease, for example, the number of dielectric grain boundaries may decrease, or the conductivity may increase, so the reliability may decrease, and the dielectric capacitance characteristics and DC (direct current) bias characteristics may also decrease. Therefore, the following research is actively being conducted to improve reliability: the dielectric capacitance is increased by increasing the crystallinity of the core portion (corresponding to the inside of the dielectric material) of the dielectric grains, and the shell portion (corresponding to the outside of the dielectric material) of the dielectric grains is manufactured to have a relatively high insulation resistance value when an electric field is applied. Summary of the invention

[0006] One aspect of the present disclosure is to achieve miniaturization and high capacitance of multi-layer electronic components.

[0007] One aspect of the present disclosure is to improve dielectric capacitance characteristics by increasing the fraction of the core (eg, the fraction of the length of the core compared to the length of the corresponding dielectric grain, or the fraction of the volume of the core compared to the volume of the corresponding dielectric grain).

[0008] An aspect of the present disclosure is to improve DC bias characteristics of multilayer electronic components.

[0009] However, the purpose of the present invention is not limited to the above contents and will be more easily understood in the course of describing specific embodiments of the present disclosure.

[0010] According to one aspect of the present disclosure, a multilayer electronic component is provided, which may include: a main body, including a dielectric layer and an internal electrode; and an external electrode, disposed on the main body, wherein the dielectric layer may include a plurality of dielectric grains, at least one of the plurality of dielectric grains may have a core-shell structure, the core-shell structure including a core portion and a shell portion surrounding at least a portion of the core portion, the cross-section of the core portion may include a polygonal shape, the average length of the plurality of dielectric grains may be greater than or equal to 80 nm and less than or equal to 200 nm, and the length of the core portion may be 70% or more compared to the length of the corresponding dielectric grain.

[0011] According to another aspect of the present disclosure, a multilayer electronic component may include: a main body, including a dielectric layer and an internal electrode; and an external electrode, disposed on the main body, wherein the dielectric layer may include a plurality of dielectric grains, wherein at least one of the plurality of dielectric grains may have a core-shell structure, the core-shell structure including a core portion and a shell portion surrounding at least a portion of the core portion, the core portion may include a polyhedral shape, an average length of the plurality of dielectric grains may be greater than or equal to 80 nm and less than or equal to 200 nm, and a volume of the core portion may be 30% or greater compared to a volume of a corresponding dielectric grain. 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 in conjunction with the accompanying drawings, in which: Figure 1 A perspective view schematically illustrates a multi-layer electronic assembly according to an embodiment of the present disclosure; Figure 2 An exploded perspective view schematically showing a stacked structure of inner electrodes; Figure 3 Schematically showing the Figure 1 A cross-sectional view taken along line II'; Figure 4 Schematically showing the Figure 1 A cross-sectional view taken along line II-II'; Figure 5 Schematically shows Figure 3 An enlarged view of the area P in FIG. Figure 6 Schematically illustrates a dielectric grain (after sintering) of an embodiment of the present disclosure; Figure 7 Schematic illustration of dielectric particles (before sintering); Fig. 8A is an image of a dielectric grain of an embodiment of the present disclosure taken by a transmission electron microscope (TEM), Figure 8B It is through Fig. 8AImages obtained by performing EDS analysis to map specific elements, Figure 8C is an image of a dielectric grain of an embodiment of the present disclosure taken by a transmission electron microscope (TEM), and Fig.8D It is through Figure 8C Image obtained by EDS analysis to map specific elements. DETAILED DESCRIPTION

[0013] Hereinafter, embodiments of the present disclosure will be described as follows with reference to the accompanying drawings. However, the present disclosure may be illustrated in many different forms and should not be construed as being limited to the specific embodiments set forth herein. More specifically, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. Therefore, for clarity of description, the shapes and sizes of the elements in the accompanying drawings may be exaggerated, and the elements represented by the same reference numerals in the accompanying drawings are the same elements.

[0014] In the accompanying drawings, irrelevant descriptions will be omitted to clearly describe the present disclosure, and the thickness may be exaggerated to clearly represent multiple layers and regions. The same or similar elements with the same functions within the scope of the same concept will be described using the same or similar reference numerals. Throughout the specification, unless otherwise explicitly stated, when a component is referred to as "including" or "comprising", it means that it may also include other components, rather than excluding other components.

[0015] In the drawings, a first direction may be defined as a stacking direction or a thickness direction, a second direction may be defined as a length direction, and a third direction may be defined as a width direction.

[0016] Multilayer electronic components.

[0017] Figure 1 A perspective view schematically illustrates a multilayer electronic component according to an embodiment of the present disclosure.

[0018] Figure 2 An exploded perspective view schematically shows a stacked structure of internal electrodes.

[0019] Figure 3 Schematically showing the Figure 1 A cross-sectional view taken along line II'.

[0020] Figure 4 Schematically showing the Figure 1 A cross-sectional view taken along line II-II'.

[0021] Figure 5 Schematically shows Figure 3 Magnified view of area P in FIG.

[0022] Figure 6A dielectric die of an embodiment of the present disclosure is schematically illustrated.

[0023] Figure 7 Dielectric particles are schematically shown.

[0024] In the following, reference will be made to Figures 1 to 7 A multilayer electronic component according to an embodiment of the present disclosure is described. In addition, a multilayer ceramic capacitor will be described as an example of a multilayer electronic component, but the description in the present disclosure can also be applied to various electronic components using dielectrics (such as inductors, piezoelectric elements, varistors, thermistors, etc.).

[0025] A multilayer electronic component 100 according to an embodiment of the present disclosure may include: a body 110 including a dielectric layer 111 and internal electrodes 121 and 122; and external electrodes 131 and 132 disposed on the body 110, wherein the dielectric layer 111 may include a plurality of dielectric grains, at least one of the plurality of dielectric grains may have a core-shell structure 10, the core-shell structure 10 includes a core portion 11 and a shell portion 12 surrounding at least a portion of the core portion 11, a cross-section of the core portion 11 may include a polygonal shape, an average length (or average particle size) of the plurality of dielectric grains may be greater than or equal to 80 nm and less than or equal to 200 nm, and a length (e.g., particle size / average particle size, diameter / average diameter) of the core portion 11 may be 70% or more compared to a length (e.g., particle size / average particle size, diameter / average diameter) of a corresponding dielectric grain 10.

[0026] The body 110 has dielectric layers 111 and internal electrodes 121 and 122 that are alternately stacked.

[0027] More specifically, the body 110 may include a capacitor forming portion Ac, which is disposed in the body 110 and includes a first internal electrode 121 and a second internal electrode 122, the first internal electrode 121 and the second internal electrode 122 are disposed opposite to each other with a dielectric layer 111 interposed between the first internal electrode 121 and the second internal electrode 122, and a capacitor is formed in the capacitor forming portion Ac.

[0028] The body 110 is not limited to a specific shape and may have a hexahedral shape or a shape similar to a hexahedral shape as shown in the figure. Since the ceramic particles included in the body 110 shrink in the process of sintering the body, the body 110 may not have a hexahedral shape with perfect straight lines. However, the body 110 may generally have a hexahedral shape.

[0029] The body 110 may have a first surface 1 and a second surface 2 opposite to each other in a first direction, a third surface 3 and a fourth surface 4 connected to the first surface 1 and the second surface 2 and opposite to each other in the second direction, and a fifth surface 5 and a sixth surface 6 connected to the first surface 1 to the fourth surface 4 and opposite to each other in a third direction.

[0030] The plurality of dielectric layers 111 forming the main body 110 may be in a sintered state, and adjacent dielectric layers 111 may be integrated with each other such that the boundary therebetween may not be easily distinguishable without using a scanning electron microscope (SEM).

[0031] There is no particular limitation on the raw material for forming the dielectric layer 111 as long as sufficient electrostatic capacitance can be obtained therefrom. Generally, perovskite (ABO3)-based materials can be used. For example, the raw material for forming the dielectric layer 111 can be a barium titanate (BaTiO3)-based material, a lead composite perovskite-based material, a strontium titanate (SrTiO3)-based material, etc. The barium titanate-based material may include BaTiO3-based ceramic particles, and the BaTiO3-based ceramic particles may be, for example, BaTiO3 and (Ba 1-x Ca x )TiO3 (0 < x < 1), Ba(Ti 1-y Ca y )O3 (0 < y < 1), (Ba 1-x Ca x )(Ti 1-y Zr y )O3 (0 < x < 1, 0 < y < 1) or Ba(Ti 1-y Zr y )O3 (0 < y < 1), etc.

[0032] In addition, for the purpose of the present disclosure, the raw material of the dielectric layer 111 may include various ceramic additives, organic solvents, binders, dispersants, etc. added to particles such as barium titanate (BaTiO3) particles.

[0033] There is no particular limitation on the thickness td of the dielectric layer 111.

[0034] However, generally, in order to achieve miniaturization and high capacitance of the multilayer electronic component, the thickness of the dielectric layer may be less than or equal to 0.6 μm, preferably less than or equal to 0.45 μm, and more preferably less than or equal to 0.4 μm.

[0035] Here, the thickness td of the dielectric layer 111 may refer to the thickness td of one dielectric layer 111 provided between the first internal electrode 121 and the second internal electrode 122, but preferably, it may refer to the average thickness of all the dielectric layers.

[0036] In addition, the thickness td of the dielectric layer 111 may refer to the dimension of the dielectric layer 111 in the first direction. Further, the thickness td of the dielectric layer 111 may refer to the average value of the thickness of the dielectric layer 111 or the average dimension of the dielectric layer 111 in the first direction.

[0037] The average size of the dielectric layer 111 in the first direction may be measured by scanning an image of a cross section of the body 110 in the first direction and the third direction with a scanning electron microscope (SEM) at a magnification of 10,000. More specifically, the average size of one dielectric layer 111 in the first direction may refer to an average value calculated by measuring the size of one dielectric layer 111 in the first direction at 30 equally spaced points in the third direction of the scanned image. 30 equally spaced points may be specified in the capacitor forming portion Ac. In addition, by extending the average value measurement to 10 dielectric layers 111, the average thickness of the dielectric layer 111 in the first direction may be more generalized.

[0038] In addition, in order to achieve miniaturization and high capacitance of multilayer electronic components, thin dielectric layers may be applied. As the dielectric layer becomes thinner, the insulation resistance value of the multilayer electronic component may decrease, for example, the number of dielectric grain boundaries may decrease, or the conductivity may increase, so the reliability may decrease, and the dielectric capacitance characteristics and DC bias characteristics may also decrease. Therefore, the crystallinity of the core portion (corresponding to the inside of the dielectric material) of the dielectric grains may be improved to increase the dielectric capacitance, and the shell portion (corresponding to the outside of the dielectric material) of the dielectric grains may be manufactured to have a high concentration of additive distribution to have a relatively high insulation resistance value when an electric field is applied, which can improve reliability.

[0039] The dielectric material (e.g., barium titanate (BaTiO3)-based dielectric material) included in the dielectric layer 111 may generally have a tetragonal lattice structure at room temperature, but a region (e.g., a shell portion) in which some elements (such as additives, etc.) are substituted may be transformed into a cubic lattice structure. By transforming the lattice structure of the shell portion in the dielectric material, it may be transformed into a phase in which a dipole moment due to the tetragonal structure and the cubic structure exists, thereby improving dielectric characteristics.

[0040] Therefore, the dielectric layer 111 according to an embodiment of the present disclosure may include a plurality of dielectric grains, and at least one of the plurality of dielectric grains may have a core-shell structure 10 including a core portion 11 and a shell portion 12 surrounding at least a portion of the core portion 11. That is, the plurality of dielectric grains may include dielectric grains having the core-shell structure 10 and dielectric grains not having the core-shell structure.

[0041] It is known that when the size of the region having a tetragonal lattice structure within a dielectric grain is larger than the size of the region having a cubic lattice structure, the effective capacitance is improved. In other words, in dielectric grains having the same size, the larger the ratio of the dielectric microstructure (tetragonal lattice structure size / cubic lattice structure size), the higher the dielectric constant can be.

[0042] In the lattice size unit, the shell region in which some elements (such as additives) are substituted may have domain walls that generate defects in the lattice due to ion defects (such as oxygen vacancies or defect dipoles), and these defective lattices may produce irreversible domain wall motion when an electric field is applied, so that the effective capacitance that can be achieved when a voltage is applied is reduced. In other words, when the shell region is doped with an additive, the insulation resistance characteristics can be improved, thereby improving reliability, but this may lead to a reduction in effective capacitance due to the application of voltage.

[0043] Therefore, if the size of the core is increased relative to the size of the dielectric grains, the effective capacitance can be improved when a DC bias voltage is applied.

[0044] In the present disclosure, in order to maximize the room temperature dielectric constant, dielectric capacitance characteristics or effective capacitance, the grain growth rate can be controlled by controlling the shape of the core in the dielectric grains, thereby ensuring the dielectric capacitance, improving the dielectric constant reduction rate, and improving the DC bias characteristics.

[0045] The dielectric grains included in the dielectric layer may have a three-dimensional shape. Since the conventional core portion has a spherical shape (circular cross section), the fraction of the core portion may be relatively reduced due to grain growth, and since sintering is performed at a low temperature due to relatively high surface energy, there may be concerns that the dispersibility of the additive may be reduced or pores may be provided at the triple point of the dielectric grain boundary, thereby reducing reliability.

[0046] On the other hand, the core portion 11 according to an embodiment of the present disclosure may have a polyhedral (eg, hexahedral) shape.

[0047] Taking the core portion 11 having a hexahedral shape as an example, since the core portion 11 of the dielectric grain 10 has a hexahedral shape, the fraction of the core portion 11 in the dielectric grain 10 can be increased (for example, the fraction of the length of the core portion compared to the length of the corresponding dielectric grain, or the fraction of the volume of the core portion compared to the volume of the corresponding dielectric grain), and the size fraction of the core portion 11 and the shell portion 12 can be optimized, and due to the thorough sintering in the sintering process, the generation of pores can be suppressed, thereby improving the dielectric capacitance and reliability.

[0048] This may be the result of manufacturing the dielectric grains before sintering them into a hexahedral shape, then doping them with additives and sintering them. Figure 7 , the core portion 11 ′ of the dielectric particle 10 ′ before sintering may have a hexahedral shape, and the shell portion 12 ′ of the dielectric particle 10 ′ obtained by doping the additive may also have a hexahedral shape, but the present disclosure is not particularly limited thereto.

[0049] In the present disclosure, dielectric particles may refer to dielectric materials before sintering, and dielectric grains may refer to dielectric materials after sintering. In addition, dielectric grain boundaries may be set between dielectric grains, and triple points may be set at points where three or more dielectric grains (or dielectric grain boundaries) contact. Unless otherwise specified, the definitions of terms described in the present disclosure may follow the definitions of terms generally used in the technical field of the present disclosure.

[0050] Generally, the size of the core observed in the dielectric grains after sintering tends to be determined by the size of the dielectric particles before sintering, and since the size of the core before sintering can be controlled so that it is not greatly affected during the sintering or grain growth operation, the size of the core of the dielectric grains after sintering can be predicted based on the size of the dielectric particles before sintering and the grain growth rate.

[0051] For dielectric grains having a fine structure, the dielectric layer 111 located in the central portion of the capacitance forming portion Ac can be easily observed based on the cross section of the body 110 in the first direction and the second direction using a scanning electron microscope (SEM) or a transmission electron microscope (TEM), and in this case, the cross section of the core portion can be exposed.

[0052] Therefore, hereinafter, the shape of the core portion 11 according to the embodiment of the present disclosure will be described based on the cross section of the core portion 11 .

[0053] The cross-section of the core portion 11 according to the embodiment of the present disclosure may include various polygonal shapes. In other words, the cross-sections of the core portions 11 of the plurality of dielectric grains may have different polygonal shapes from each other.

[0054] Since the cross section of the core portion 11 has a polygonal shape, the core portion 11 may have a high fraction (ie, the proportion of the core portion is high) in the dielectric grain 10 having the core-shell structure, and thus dielectric capacitance and DC bias characteristics may be improved.

[0055] In the present disclosure, a polygon refers not only to a polygon formed by straight lines but also includes a polygon with rounded corners (no vertices) or other polygonal shapes.

[0056] Here, the polygon may include at least one of the following shapes: a triangle, including an equilateral triangle and an isosceles triangle; a quadrilateral: including a trapezoid (e.g., an equilateral trapezoid) and a parallelogram (e.g., a square, a rectangle, a rhombus); a pentagon; and a hexagon. According to the definition of the polygon, the sum of the interior angles of the polygon may be substantially at least one of 180°, 360°, 540°, and 720°, but the present disclosure is not particularly limited thereto. Here, the fact that the sum of the interior angles is substantially at least one of 180°, 360°, 540°, and 720° may mean that an error of approximately ±5° is included.

[0057] In particular, a polygon in the present disclosure may refer to a polygon obtained from a cross section of a cube.

[0058] In addition, at least a portion of the cross-sectional shape of the core portion 11 may be substantially parallel to the dielectric grain boundary. Therefore, the dielectric characteristics may be improved compared to a core portion having a circular cross section.

[0059] Here, the fact that at least a portion of the cross-sectional shape of the core portion 11 is substantially parallel to the dielectric grain boundary may mean that one boundary line between the core portion 11 and the shell portion 12 is substantially parallel to the dielectric grain boundary. Substantially parallel may not mean absolutely parallel, but may mean that 50% or more of one side (virtual straight line) of the core portion 11 (to be described later) as the boundary line between the core portion 11 and the shell portion 12 may be substantially parallel to the dielectric grain boundary.

[0060] When described with reference to the embodiments of the present disclosure, Fig. 8A is an image of a dielectric grain of an embodiment of the present disclosure taken by a transmission electron microscope (TEM), Figure 8B It is through Fig. 8A Image obtained by performing energy dispersive X-ray spectroscopy (EDS) analysis to map the element dysprosium (Dy). Figure 8C is an image of a dielectric grain of an embodiment of the present disclosure taken by a transmission electron microscope (TEM), and Fig.8D It is through Figure 8C Image obtained by EDS analysis to map the element dysprosium (Dy).

[0061] from Figure 8B and Fig.8D It can be seen that at least one of the plurality of dielectric grains included in the image having a size of 1.0 μm (horizontal)×0.6 μm (vertical) may have a core-shell structure, and it can be seen that a plurality of polygonal core portions having different shapes exist.

[0062] Reference Figure 6 , the internal angle of the polygon can be obtained by measuring an angle ∠a° between straight lines L1 and L2 obtained by extending different sides based on a cross section of the core portion 11 photographed with a scanning electron microscope (SEM) or a transmission electron microscope (TEM).

[0063] Here, the side of the polygon may refer to a straight line having a length of 50% or greater based on the minimum length of the center of the core portion 11 passing through the corresponding dielectric grain, and the polygon may refer to a shape in which the cross-section of the core portion 11 includes three or more sides, and preferably, may refer to a shape in which the cross-section of the core portion 11 includes greater than or equal to three sides and less than or equal to six sides, but the present disclosure is not limited thereto.

[0064] Furthermore, the volume of the core portion 11 compared to the volume of the corresponding dielectric grain 10 (ie, the volume fraction of the core portion 11 ) may preferably be 30% or more.

[0065] The volume of the core portion 11 may be 30% or more compared to the volume of the corresponding dielectric grain 10 having the core-shell structure, so that target dielectric capacitance and room temperature dielectric constant may be achieved, and DC bias characteristics may be improved.

[0066] When the volume fraction of the core portion 11 is less than 30%, the dielectric properties of the core portion 11 may be insufficient, a decrease in the dielectric constant may be caused, and there may be a concern that DC bias properties or high temperature reliability may be deteriorated.

[0067] The length of the core portion 11 may be 70% or more compared to the length of the corresponding dielectric grain 10 .

[0068] Here, the length of the core portion 11 may refer to a maximum length D among the lengths of a straight line passing through the center of the core portion 11. In addition, the length of the corresponding dielectric grain 10 including the core portion 11 may refer to a maximum length among the lengths of a straight line obtained by extending a straight line passing through the center of the core portion 11, and may refer to a value obtained by adding the length of the core portion 11 and the length of the shell portion 12.

[0069] The length of the core portion 11 may be 70% or more compared to the length of the corresponding dielectric grain 10 having the core-shell structure, so that target dielectric capacitance and room temperature dielectric constant may be achieved, and DC bias characteristics may be improved.

[0070] When the length of the core portion 11 is less than 70% compared to the length of the corresponding dielectric grain 10 having the core-shell structure, it may be difficult to form sufficient dielectric capacitance, and there may be a concern that DC bias characteristics may deteriorate.

[0071] In addition, the length of the core portion 11 may be 95% or less, or 90% or less compared to the length of the corresponding dielectric grain 10, but the present disclosure is not particularly limited thereto. When the area of ​​the shell portion 12 becomes insufficient, this may cause a problem of reduced reliability, so it is expected that it may be preferable to form the shell portion 12 to a level where reliability does not deteriorate, so an example of the upper limit value is provided.

[0072] The shell portion 12 may include a rare earth element, and a concentration of the rare earth element of the shell portion 12 may be higher than a concentration of the rare earth element of the core portion 11 .

[0073] The rare earth element may include at least one of yttrium (Y), dysprosium (Dy), holmium (Ho), erbium (Er), gadolinium (Gd), cerium (Ce), neodymium (Nd), samarium (Sm), terbium (Tb), thorium (Tm), lanthanum (La), and ytterbium (Yb).

[0074] In addition, the core 11 and the shell 12 can be distinguished by analysis of scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) or transmission electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), and can be distinguished by measuring the content of rare earth elements contained in dielectric grains having a core-shell structure.

[0075] For example, dysprosium (Dy), a rare earth element, is difficult to diffuse into the core, so during EDS analysis of a dielectric grain, a region into which Dy is not diffused may be defined as the core, and a region covering or surrounding the core may be defined as the shell. In other words, a region from the outside of the core to the boundary of the dielectric grain in which the concentration of the rare earth element is measured to be relatively high may be defined as the shell.

[0076] Alternatively, in one dielectric grain having a core-shell structure, when line profile analysis is used, a region with a low Dy content may be defined as a core portion, and a region with a high Dy content may be defined as a shell portion based on a point where the Dy content changes rapidly.

[0077] The dielectric grains according to the embodiment of the present disclosure may have an average length of greater than or equal to 80 nm and less than or equal to 200 nm.

[0078] The average length of the dielectric grains may be 80 nm or more and 200 nm or less, and thus, even in a dielectric layer having an average thickness of 0.45 μm or less, a dielectric constant or a dielectric capacitance may be excellent.

[0079] When the average length of the dielectric grains is less than 80 nm, there may be a concern that sufficient dielectric capacitance may not be ensured or the temperature coefficient of capacitance (TCC) may decrease, and when the average length of the dielectric grains exceeds 200 nm, insulation resistance characteristics may deteriorate.

[0080] In an embodiment of the present disclosure, when the average thickness of the dielectric layer is less than or equal to 0.45 μm, the average length of the dielectric grains is greater than or equal to 80 nm and less than or equal to 200 nm, and the cross-section of the core 11 of the dielectric grains includes a polygon, which can further improve the dielectric properties or DC bias characteristics.

[0081] Here, the average length of the dielectric crystal grains may be an average value obtained by measuring the maximum diameter of the dielectric crystal grains observed in an image of an arbitrary 10 μm×10 μm region in the dielectric layer of the capacitor forming portion Ac photographed using a scanning electron microscope (SEM) or a transmission electron microscope (TEM). In this case, the average length of the dielectric crystal grains may be calculated not only by the dielectric crystal grains 10 having a core-shell structure but also by the dielectric crystal grains not having a core-shell structure.

[0082] The internal electrodes 121 and 122 may be alternately stacked with the dielectric layers 111 .

[0083] The internal electrodes 121 and 122 may include first and second internal electrodes 121 and 122 that may be alternately disposed opposite to each other with the dielectric layer 111 interposed therebetween and may be exposed to the third and fourth surfaces 3 and 4 of the body 110 , respectively.

[0084] More specifically, the first inner electrode 121 may be spaced apart from the fourth surface 4 and exposed through the third surface 3, and the second inner electrode 122 may be spaced apart from the third surface 3 and exposed through the fourth surface 4. The first outer electrode 131 may be disposed on the third surface 3 of the body and connected to the first inner electrode 121, and the second outer electrode 132 may be disposed on the fourth surface 4 of the body and connected to the second inner electrode 122.

[0085] That is, the first internal electrode 121 is not connected to the second external electrode 132 but is connected to the first external electrode 131, and the second internal electrode 122 is not connected to the first external electrode 131 but is connected to the second external electrode 132. In this case, the first internal electrode 121 and the second internal electrode 122 may be electrically isolated from each other by the dielectric layer 111 disposed therebetween.

[0086] In addition, the body 110 may be formed by alternately stacking ceramic green sheets on which the conductive paste for the first internal electrode 121 is printed and ceramic green sheets on which the conductive paste for the second internal electrode 122 is printed, and then sintering.

[0087] The material for forming the internal electrodes 121 and 122 is not particularly limited, and a material having excellent conductivity may be used as the material forming the internal electrodes 121 and 122. For example, the internal electrodes 121 and 122 may include at least one of nickel (Ni), copper (Cu), palladium (Pd), silver (Ag), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), and alloys thereof.

[0088] In addition, the internal electrodes 121 and 122 may be formed by printing a conductive paste for internal electrodes on a ceramic green sheet, the conductive paste including at least one of nickel (Ni), copper (Cu), palladium (Pd), silver (Ag), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), and alloys thereof. The method of printing the conductive paste for the internal electrodes may be a screen printing method, a gravure printing method, etc., but the present disclosure is not limited thereto.

[0089] In addition, the thickness te of the internal electrodes 121 and 122 does not need to be particularly limited.

[0090] However, in order to more easily achieve miniaturization and high capacitance of the multilayer electronic component, the thickness of the internal electrodes 121 and 122 may be equal to or less than 0.6 μm, preferably equal to or less than 0.45 μm, and more preferably equal to or less than 0.4 μm.

[0091] Here, the thickness te of the internal electrodes 121 and 122 may refer to the size of the internal electrodes 121 and 122 in the first direction. In addition, the thickness te of the internal electrodes 121 and 122 may refer to the average thickness of the internal electrodes 121 and 122 and may refer to the average size of the internal electrodes 121 and 122 in the first direction.

[0092] The average size of the internal electrodes 121 and 122 in the first direction may be measured by scanning an image of a cross section of the body 110 in the first direction and the third direction at a magnification of 10000 with a scanning electron microscope (SEM). More specifically, the average size of one internal electrode in the first direction may refer to an average value calculated by measuring the size of one internal electrode in the first direction at 30 equally spaced points in the third direction of the scanned image. 30 equally spaced points may be specified in the capacitance forming portion Ac. In addition, by extending the average value measurement to 10 internal electrodes, the average size (such as thickness) of the internal electrodes 121 and 122 in the first direction may be more generalized.

[0093] In addition, the body 110 may include cover parts 112 and 113 disposed on both surfaces of the capacitance forming part Ac in the first direction.

[0094] More specifically, the cover portions 112 and 113 may include an upper cover portion 112 disposed above the capacitance forming portion Ac in the first direction and a lower cover portion 113 disposed below the capacitance forming portion Ac in the first direction.

[0095] The upper cover portion 112 and the lower cover portion 113 may be formed by stacking a single dielectric layer or two or more dielectric layers on the upper surface and the lower surface of the capacitor forming portion Ac in the first direction, respectively, and the upper cover portion 112 and the lower cover portion 113 may be substantially used to prevent the internal electrodes 121 and 122 from being damaged due to physical stress or chemical stress.

[0096] The upper and lower covers 112 and 113 do not include the internal electrodes 121 and 122 and may include the same material as the dielectric layer 111. That is, the upper and lower covers 112 and 113 may include a ceramic material, such as a barium titanate (BaTiO3)-based ceramic material.

[0097] Furthermore, the thickness tc of the covering portions 112 and 113 does not need to be particularly limited.

[0098] However, in order to more easily achieve miniaturization and high capacitance of multilayer electronic components, in ultra-small products, the thickness tc of the covers 112 and 113 may be 100 μm or less, preferably 30 μm or less, and more preferably 20 μm or less.

[0099] Here, the thickness tc of the covers 112 and 113 may refer to the size of the covers 112 and 113 in the first direction. In addition, the thickness tc of the covers 112 and 113 may refer to the average thickness of the covers 112 and 113 and may refer to the average size of the covers 112 and 113 in the first direction.

[0100] The average thickness of the covering portions 112 and 113 in the first direction may be measured by scanning an image of a cross section of the body 110 in the first direction and the third direction using a scanning electron microscope (SEM) at a magnification of 10000. More specifically, the average size of the covering portions 112 and 113 in the first direction may be an average value calculated by measuring the size of one covering portion in the first direction at 30 equally spaced points in the third direction of the scanned image.

[0101] In addition, the average size of the covering portion in the first direction measured by the above method may be substantially the same as the average size of the covering portion in the first direction measured in a cross section of the body 110 in the first and second directions.

[0102] In addition, the side edge portions 114 and 115 may be provided on both surfaces of the capacitance forming portion Ac in the third direction.

[0103] More specifically, the side edge portions 114 and 115 may include a first side edge portion 114 disposed on one surface of the capacitance forming portion Ac in the third direction and a second side edge portion 115 disposed on the other surface of the capacitance forming portion Ac in the third direction. That is, the side edge portions 114 and 115 may be disposed on both surfaces of the capacitance forming portion Ac in the third direction.

[0104] like Figure 4 As shown, the side edge parts 114 and 115 may refer to regions between both ends of the internal electrodes 121 and 122 in the third direction and a boundary surface of the body 110 based on the cross-sections of the body 110 in the first and third directions.

[0105] The side margin parts 114 and 115 may basically serve to prevent the internal electrodes 121 and 122 from being damaged due to physical stress or chemical stress.

[0106] The side edge portions 114 and 115 can be formed by applying a conductive paste to areas of the ceramic green sheet other than the areas where the side edge portions 114 and 115 will be formed to form the internal electrodes 121 and 122, and in order to suppress the step difference caused by the internal electrodes 121 and 122, after stacking the internal electrodes 121 and 122, the stack is cut to expose the internal electrodes 121 and 122 to both surfaces of the capacitor forming portion Ac in the third direction, and a single dielectric layer or two or more dielectric layers are stacked on both surfaces of the capacitor forming portion Ac in the third direction, thereby forming the side edge portions 114 and 115.

[0107] The first and second side margin parts 114 and 115 do not include the internal electrodes 121 and 122 and may include the same material as the dielectric layer 111. That is, the first and second side margin parts 114 and 115 may include a ceramic material, for example, a barium titanate (BaTiO3)-based ceramic material.

[0108] In addition, the widths wm of the first side margin portion 114 and the second side margin portion 115 do not need to be particularly limited.

[0109] However, in order to more easily achieve miniaturization and high capacitance of the multilayer electronic component 100, in an ultra-small product, the width wm of the first side edge portion 114 and the second side edge portion 115 may be less than or equal to 100 μm, preferably less than or equal to 30 μm, and more preferably less than or equal to 20 μm.

[0110] Here, the width wm of the side edge portions 114 and 115 may refer to the size of each of the side edge portions 114 and 115 in the third direction. In addition, the width wm of the side edge portions 114 and 115 may refer to the average width of the side edge portions 114 and 115, and may refer to the average size of the side edge portions 114 and 115 in the third direction.

[0111] The average size of the side edge portions 114 and 115 in the third direction may be measured by scanning an image of a cross section of the body 110 in the first direction and the third direction using a scanning electron microscope (SEM) at a magnification of 10000. More specifically, the average size of the side edge portions 114 and 115 in the third direction may refer to an average value calculated by measuring the size of one side edge portion in the third direction at 10 equally spaced points of the scanned image in the first direction.

[0112] In the present embodiment, a structure has been described in which the multilayer electronic component 1000 has two external electrodes 131 and 132. However, the number and shape of the external electrodes 131 and 132 may vary depending on the shape of the internal electrodes 121 and 122 or other purposes.

[0113] The external electrodes 131 and 132 may be disposed on the body 110 and connected to the internal electrodes 121 and 122 .

[0114] More specifically, the external electrodes 131 and 132 may include a first external electrode 131 and a second external electrode 132, which may be disposed on the third surface 3 and the fourth surface 4 of the body 110, respectively, and respectively connected to the first internal electrode 121 and the second internal electrode 122. That is, the first external electrode 131 may be disposed on the third surface 3 of the body and connected to the first internal electrode 121, and the second external electrode 132 may be disposed on the fourth surface 4 of the body and connected to the second internal electrode 122.

[0115] The external electrodes 131 and 132 may be formed using any material such as metal as long as it has conductivity. Specific materials of the external electrodes 131 and 132 may be determined by considering electrical characteristics, structural stability, etc., and may also have a multi-layered structure.

[0116] For example, the external electrodes 131 and 132 may include electrode layers 131 a and 132 a disposed on the body 110 and plating layers 131 b and 132 b disposed on the electrode layers 131 a and 132 a .

[0117] The electrode layers 131 a and 132 a may be sintered electrodes including a conductive metal and glass, or may be resin-based electrodes including a conductive metal and resin.

[0118] In addition, the electrode layers 131 a and 132 a may be formed by sequentially forming a sintered electrode and a resin-based electrode on the body 110 .

[0119] In addition, the external electrodes 131 and 132 may have a form in which a sintered electrode and a resin-based electrode are sequentially formed on the body. In addition, the external electrodes 131 and 132 may be formed by a method of transferring a sheet including a conductive metal to the body, or may be formed by a method of transferring a sheet including a conductive metal to a sintered electrode.

[0120] The conductive metal used for the electrode layers 131a and 132a is not particularly limited as long as it is a material that can be electrically connected to the internal electrodes 121 and 122 to form capacitance, and may include, for example, at least one of nickel (Ni), copper (Cu), palladium (Pd), silver (Ag), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), and alloys thereof. The electrode layers 131a and 132a may be formed by coating a conductive paste prepared by adding glass frit to a conductive metal powder and then sintering it.

[0121] The plating layers 131 b and 132 b may be used to improve mounting characteristics.

[0122] The type of the plating layers 131 b and 132 b is not particularly limited, and may be a plating layer including at least one of nickel (Ni), tin (Sn), palladium (Pd), and alloys thereof, and the plating layers 131 b and 132 b may be formed as a single layer or multiple layers.

[0123] As a more specific example of the plating layers 131b and 132b, the plating layers 131b and 132b may be Ni plating layers and / or Sn plating layers, or the plating layers 131b and 132b may have a form in which a Ni plating layer and a Sn plating layer are sequentially formed on the electrode layers 131a and 132a, or may have a form in which a Sn plating layer, a Ni plating layer, and a Sn plating layer are sequentially formed. In addition, the plating layers 131b and 132b may include a plurality of Ni plating layers and / or a plurality of Sn plating layers.

[0124] The size of the multilayer electronic component 100 does not need to be particularly limited.

[0125] However, in order to achieve both miniaturization and high capacitance, the number of stacked layers should be increased by thinning the dielectric layers and the internal electrodes, and in a multilayer electronic component 100 having a size of 3216 (length × width, 3.2 mm × 1.6 mm) or less, preferably, 1005 (length × width, 1.0 mm × 0.5 mm) or less, the reliability improvement effect according to the present disclosure can become more significant.

[0126] Hereinafter, the present disclosure will be described in more detail through examples, but these examples are intended to help specifically understand the present disclosure, and the scope of the present disclosure is not limited by the examples.

[0127] (Example).

[0128] As the main component matrix material, BaTiO3 particles with a cubic shape having an average particle size of 100nm forming the core and BaTiO3 particles with a spherical shape having an average particle size of 10nm forming the shell are mixed and used according to a designed ratio. Using zirconium oxide beads as a mixing / dispersion medium, additive particles such as dysprosium (Dy), ethanol / toluene solvent, cubic BaTiO3 and spherical BaTiO3 are mixed together with a dispersant and milled for 5 hours, and then a binder is mixed and milled for another 5 hours. The slurry prepared in this way is used to manufacture molded sheets with a thickness of 0.8μm and 0.6μm using a molding machine for preparing sheets. Nickel (Ni) inner electrodes are printed on the molded sheets. The upper and lower covers are manufactured by stacking 25 layers of cover sheets with an average thickness of 10μm to 13μm, respectively, and 31 layers of sheets printed with nickel (Ni) inner electrodes are pressed, and then they are stacked to manufacture rods. The pressed rod was cut into a sheet having a size of 3216 (length × width: 3.2 mm × 1.6 mm) using a cutter. The manufactured MLCC sheet having a size of 3216 was plasticized and sintered for 10 minutes under the conditions of a reducing atmosphere of 0.1% H2 / 99.9% N2 to 0.5% H2 / 99.5% N2 (H2O / H2 / N2 atmosphere) at a temperature of 1100°C to 1150°C, and then oxidized in a N2 atmosphere at 1000°C for 0.5 hours. Here, 0.1% hydrogen concentration (0.1% H2) corresponds to a condition where the electromotive force of the oxygen partial pressure measuring device is 670 mV in a measurement environment at 850°C, and 0.5% hydrogen concentration (0.5% H2) corresponds to a condition where the electromotive force is 760 mV. For the fired sheet, the outer electrode is completed by a termination process using copper (Cu) paste and an electrode sintering process. Thus, an MLCC sheet having a 3216 size in which the thickness of the dielectric layer after sintering (referring to the dielectric layer provided between the internal electrodes) was about 0.4 μm and the number of the dielectric layers was 30 was manufactured.

[0129] The room temperature capacitance and dielectric loss of the MLCC sheet were measured using an LCR meter under 1kHz and AC 0.5V / μm conditions. The dielectric constant of the dielectric layer of the MLCC sheet was calculated from the capacitance, dielectric thickness, inner electrode area, and number of stacked layers of the MLCC sheet. Ten samples were taken respectively and DC 10V / μm was applied thereto, and the room temperature insulation resistance was measured after 60 seconds. The change in capacitance according to temperature was measured in the temperature range of -55°C to 105°C. A highly accelerated life test (HALT) was performed by applying a voltage corresponding to an electric field of 23V / μm to 40 samples of each of the comparative examples and examples at a temperature of 125°C and measuring the time when failure occurred to calculate the mean time to failure (MTTF). In addition, DC voltages of 1V and 3V were applied to the MLCC sheet, and the DC bias change rate of capacitance was measured.

[0130] In the comparative example, conventional round dielectric particles were used, and as a result of TEM-EDS observation, it was confirmed that the shape of the core portion after sintering was substantially round, excluding core portions of different polygonal shapes.

[0131] In the example, the hexahedral-shaped dielectric particles of the present disclosure were used, and as a result of TEM-EDS observation, it was confirmed that the plurality of core portions after sintering had different polygonal shapes. The manufacturing conditions of the example were the same as those of the comparative example.

[0132] The DC bias change rate refers to the change rate of the dielectric capacitance when DC voltages of 1 V and 3 V are applied, respectively, based on the dielectric capacitance when no DC voltage is applied.

[0133] Highly accelerated life testing (HALT) was performed by measuring the mean time to failure (MTTF) when a voltage of 1.5 Vr was applied at a temperature of 125°C. 9 The initial insulation resistance (R0) of Ω was determined, and when a short circuit occurred, failure was determined. 400 sample pieces were used in both the comparative example and the example, and the average time when all the sample pieces failed was calculated as MTTF.

[0134] [Table 1] .

[0135] As can be seen from Table 1, in the case of the comparative example, the dielectric constant is 3230, when a DC voltage of 1V is applied, the DC bias change rate shows a capacitance change rate of -27% compared to no voltage applied, and when a DC voltage of 3V is applied, the DC bias change rate shows a capacitance change rate of -77%, and during the HALT evaluation, the MTTF is measured to be 32.5 hours. On the other hand, in the case of the example, the dielectric constant is 3810, which is improved compared to the dielectric constant in the comparative example, and when a DC voltage of 1V is applied, the DC bias change rate shows a capacitance change rate of -18% compared to no voltage applied, and when a DC voltage of 3V is applied, the DC bias change rate shows a capacitance change rate of -68%, so it can be seen that the capacitance change rate in the example is improved compared to the capacitance change rate in the comparative example. In addition, during the HALT evaluation, the MTTF measured in the example is 54.9 hours, and it can be seen that the average failure time in the example is improved compared to the average failure time (32.5 hours) in the comparative example. From this, it can be seen that the dielectric constant, DC bias characteristics, and MTTF of the multilayer electronic component including the dielectric grains having the cores of the polygonal shape are improved compared to the multilayer electronic component including the dielectric grains having the cores of the circular shape.

[0136] As described above, as one of the various effects of the present disclosure, miniaturization and high capacitance of a multilayer electronic component are achieved.

[0137] One of the various effects of the present disclosure is to improve the room temperature dielectric constant characteristics of a multilayer electronic component.

[0138] One of the various effects of the present disclosure is to improve the DC bias characteristics of a multilayer electronic component.

[0139] Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited by the above embodiments and drawings, but by the appended claims. Therefore, within the scope of the technical ideas of the present disclosure described in the claims, those skilled in the art will be able to make various forms of substitutions, modifications and changes, which also fall within the scope of the present disclosure.

[0140] In addition, the expression "one embodiment" used in the present disclosure does not refer to the same embodiment, but is provided to emphasize and describe different unique features. However, the one embodiment presented above does not exclude the combination of features with another embodiment. For example, even if a matter described in a specific embodiment is not described in another embodiment, it can be understood as a description associated with another embodiment, unless there is a contradictory or conflicting description with the matter in another embodiment.

[0141] The terms used in the present disclosure are only used to describe the embodiments and are not intended to limit the present disclosure. In this case, unless the context clearly indicates otherwise, the singular expression also includes the plural expression.

[0142] While example embodiments have been shown and described above, it will be readily 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 electronic component comprising: a body including a dielectric layer and an inner electrode; and an outer electrode, disposed on the body, Wherein, the dielectric layer includes a plurality of dielectric grains. At least one of the plurality of dielectric grains has a core-shell structure including a core portion and a shell portion surrounding at least a portion of the core portion, The cross-section of the core portion comprises a polygonal shape, The average length of the plurality of dielectric grains is greater than or equal to 80 nm and less than or equal to 200 nm, and The length of the core portion is 70% or more compared to the length of the corresponding dielectric grain.

2. The multilayer electronic component according to claim 1, wherein Two or more dielectric grains among the plurality of dielectric grains have the core-shell structure, and in the two or more dielectric grains, cross sections of corresponding core portions have polygonal shapes different from each other.

3. The multilayer electronic component according to claim 1, wherein: The polygonal shape of the core portion includes at least one of the following shapes: a triangle, including an equilateral triangle and an isosceles triangle; a quadrilateral, including a trapezoid and a parallelogram; a pentagon; and a hexagon, and Among them, the parallelogram includes a square, a rectangle and a rhombus, and the trapezoid includes an equilateral trapezoid.

4. The multilayer electronic component according to claim 1, wherein: The sum of the interior angles of the polygonal shape is at least one of 180°, 360°, 540° and 720°.

5. The multilayer electronic component according to claim 4, wherein: The internal angle includes angles between straight lines obtained by extending different sides of the polygonal shape.

6. The multilayer electronic component according to claim 1, wherein: The dielectric grain boundaries are disposed between the plurality of dielectric grains, and At least a portion of the cross section of the core portion is parallel to the dielectric grain boundary.

7. The multilayer electronic component according to claim 1, wherein: The shell portion includes a rare earth element.

8. The multilayer electronic component according to claim 1, wherein The dielectric layer includes a plurality of dielectric layers, and at least one of the plurality of dielectric layers has an average thickness of 0.45 μm or less.

9. The multilayer electronic component according to claim 1, wherein: The internal electrode includes a plurality of internal electrodes, and at least one of the plurality of internal electrodes has an average thickness of 0.45 μm or less.

10. The multilayer electronic component according to claim 1, wherein The main body includes a capacitance forming part and a covering part, the capacitance forming part includes the dielectric layer and the inner electrodes arranged alternately with the dielectric layer in a first direction, the covering part is respectively arranged on two surfaces of the capacitance forming part in the first direction, the main body has a first surface and a second surface opposite to each other in the first direction, a third surface and a fourth surface connected to the first surface and the second surface and opposite to each other in the second direction, and a fifth surface and a sixth surface connected to the first surface to the fourth surface and opposite to each other in the third direction, and The main body further includes side edge portions, which are respectively provided on both surfaces of the capacitance forming portion in the third direction.

11. The multilayer electronic component according to claim 1, wherein The size of the multilayer electronic component is 1005 or less, wherein 1005 represents a length×width of 1.0 mm×0.5 mm.

12. The multilayer electronic component according to claim 1, wherein The external electrode includes: an electrode layer disposed on the body and connected to the internal electrode; and a plating layer disposed on the electrode layer.

13. A multilayer electronic component comprising: a body including a dielectric layer and an inner electrode; and an outer electrode, disposed on the body, Wherein, the dielectric layer includes a plurality of dielectric grains. At least one of the plurality of dielectric grains has a core-shell structure including a core portion and a shell portion surrounding at least a portion of the core portion, The core portion comprises a polyhedral shape, The average length of the plurality of dielectric grains is greater than or equal to 80 nm and less than or equal to 200 nm, and The volume of the core portion is 30% or more compared to the volume of the corresponding dielectric grain.

14. The multilayer electronic component according to claim 13, wherein: Two or more dielectric grains among the plurality of dielectric grains have the core-shell structure, and in the two or more dielectric grains, cross sections of corresponding core portions have polygonal shapes different from each other.

15. The multilayer electronic component according to claim 13, wherein The cross-section of the core portion includes a polygonal shape, and the polygonal shape includes at least one of the following shapes: a triangle, including an equilateral triangle and an isosceles triangle; a quadrilateral, including a trapezoid and a parallelogram; a pentagon; and a hexagon, and Among them, the parallelogram includes a square, a rectangle and a rhombus, and the trapezoid includes an equilateral trapezoid.

16. The multilayer electronic component according to claim 13, wherein: A cross-section of the core portion includes a polygonal shape, and a sum of interior angles of the polygonal shape is at least one of 180°, 360°, 540°, and 720°.

17. The multilayer electronic component according to claim 13, wherein: The dielectric grain boundaries are disposed between the plurality of dielectric grains, and At least a portion of a cross section of the core portion is parallel to the dielectric grain boundary.

18. The multilayer electronic component according to claim 13, wherein: The dielectric layer includes a plurality of dielectric layers, and at least one of the plurality of dielectric layers has an average thickness of 0.45 μm or less.

19. The multilayer electronic component according to claim 13, wherein: The internal electrode includes a plurality of internal electrodes, and at least one of the plurality of internal electrodes has an average thickness of 0.45 μm or less.

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