Multi-layer electronic component

Abstract

The present invention provides a multilayer electronic component, and the multilayer electronic component includes: a main body, including a dielectric layer and internal electrodes, the internal electrodes being alternately stacked and the dielectric layer being interposed between the internal electrodes; and external electrodes, disposed on the main body and connected to the internal electrodes. At least one of the internal electrodes is thicker at an end portion in a length direction of the main body than at a central portion of the internal electrode, and a ratio t2 / t1 of a thickness t2 of the end portion to a thickness t1 of the central portion satisfies 1.1 ≤ t2 / t1 ≤ 1.5.

Description

[0001] This application claims the benefit of priority of Korean Patent Application No. 10-2019-0158868, filed on December 03, 2019 with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes. Technical Field

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

[0003] A multi-layer ceramic capacitor (MLCC) (multi-layer electronic component) is a chip capacitor mounted on a printed circuit board of various electronic products such as imaging devices (such as liquid crystal displays (LCDs), plasma display panels (PDPs), etc.), computers, smart phones, mobile phones, etc., for charging or discharging.

[0004] Such multi-layer ceramic capacitors can be used as components of various electronic devices due to their small size, high capacitance, and easy installation. As components of electronic devices have been miniaturized in recent years, the demand for miniaturization and high capacitance of multi-layer ceramic capacitors has increased.

[0005] In order to miniaturize a multi-layer ceramic capacitor and increase the capacitance of the multi-layer ceramic capacitor, a technique for reducing the thickness of the inner electrode and the dielectric layer is required.

[0006] However, as the dielectric layer and the inner electrode become thinner, copper (Cu) diffuses into the inner electrode during firing of the outer electrode, and radiation cracks are frequently generated.

[0007] Radiation cracks caused by volume expansion of the inner electrode increase the short-circuit rate of the multi-layer ceramic capacitor.

[0008] Radiation cracks generated due to copper (Cu) diffusing into the inner electrode are caused by a difference in diffusion coefficients between copper (Cu) and nickel (Ni) contained in the inner electrode.

[0009] For example, according to a diffusion coefficient comparison table, it can be seen that the diffusion coefficient of copper (Cu) at 750 °C is about 100 times that of nickel (Ni).

[0010] As described above, since the difference in diffusion coefficients between copper (Cu) and nickel (Ni) is relatively large, the diffusion of copper (Cu) into nickel (Ni) is greater than the diffusion of nickel (Ni) into copper (Cu). Therefore, radiation cracks are generated due to volume expansion of the inner electrode.

[0011] In order to prevent radiation cracks at the ends of the inner electrodes, research is being conducted to minimize the diffusion of copper (Cu), while changing the paste composition and firing conditions of the outer electrodes. However, it is difficult to effectively control the diffusion of copper (Cu) through the concentration gradient during firing (i.e., the difference in the concentration of copper between the inner electrode mainly containing nickel (Ni) and the outer electrode mainly containing copper (Cu) during firing). SUMMARY OF THE INVENTION

[0012] The present invention content is provided to introduce selected concepts in a simplified form, and the concepts are further described in the detailed description below. The present invention content is neither intended to define the key features or essential features of the claimed subject matter, nor intended to be used as an aid in determining the scope of the claimed subject matter.

[0013] One aspect of the present disclosure is to provide a multilayer electronic component.

[0014] According to one aspect of the present disclosure, a multilayer electronic component includes: a body including dielectric layers and inner electrodes, the inner electrodes being alternately stacked and the dielectric layers being interposed between the inner electrodes; and outer electrodes disposed on the body and connected to the inner electrodes. At least one of the inner electrodes is thicker at an end in the longitudinal direction of the body than at a central portion of the inner electrode, and a ratio t2 / t1 of a thickness t2 of the end to a thickness t1 of the central portion satisfies 1.1 ≤ t2 / t1 ≤ 1.5.

[0015] According to another aspect of the present disclosure, a multilayer electronic component includes: outer electrodes disposed on opposite side surfaces of the body of the multilayer electronic component in the longitudinal direction; and inner electrodes having opposite polarities and alternately disposed with dielectric layers interposed between the inner electrodes, each of the inner electrodes having an end in contact with a corresponding outer electrode and a central portion extending away from the end in the longitudinal direction, wherein a ratio t2 / t1 of a thickness t2 of at least one of the ends to a thickness t1 of the corresponding central portion satisfies 1.1 ≤ t2 / t1 ≤ 1.5.

[0016] According to another aspect of the present disclosure, a multi-layer electronic component includes: a body including: a first inner electrode exposed through a first side surface of the body, a second inner electrode exposed through a second side surface of the body opposite to the first side surface in the length direction, and a dielectric layer interposed between each pair of consecutive first inner electrodes and second inner electrodes, the first inner electrode, the second inner electrode, and the dielectric layer being stacked in the thickness direction; a first outer electrode and a second outer electrode respectively disposed on the first side surface and the second side surface, wherein each of the first inner electrode and the second inner electrode has an end portion that does not overlap with an adjacent inner electrode and a central portion extending away from the corresponding outer electrode, and a ratio t2 / t1 of a thickness t2 of at least one of the end portions to a thickness t1 of the corresponding central portion satisfies 1.1 ≤ t2 / t1 ≤ 1.5.

[0017] According to another aspect of the present disclosure, a multi-layer electronic component includes: a body including a dielectric layer and inner electrodes, the inner electrodes being alternately stacked and the dielectric layer being interposed between the inner electrodes; and outer electrodes disposed on the body and connected to the inner electrodes, wherein at least one of the inner electrodes is thicker at an end portion in the length direction of the body than at a central portion of the inner electrode, and the inner electrode contains 5.0 wt% to 20.0 wt% of copper. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other aspects, features, and advantages of the present disclosure will be more clearly understood from the following detailed description in conjunction with the accompanying drawings, in which:

[0019] Figure 1 A perspective view of a multi-layer electronic component according to an embodiment of the present disclosure is schematically shown;

[0020] Figure 2 is a schematic cross-sectional view taken along line I-I'; Figure 1 of

[0021] Figure 3 is Figure 2 an enlarged view of the P region of; and

[0022] Figure 4 is a schematic exploded perspective view of a body having a dielectric layer and inner electrodes stacked according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0023] The following specific embodiments are provided to assist the reader in obtaining a comprehensive understanding of the methods, apparatuses, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatuses, and / or systems described herein will be apparent to those of ordinary skill in the art. The order of operations described herein is merely exemplary and is not limited to the order set forth herein, but rather, changes that will be apparent to those of ordinary skill in the art may be made, except for operations that must occur in a particular order. Additionally, descriptions of functions and structures known to those of ordinary skill in the art may be omitted for increased clarity and conciseness.

[0024] The features described herein may be implemented in different forms and are not to be construed as limited to the examples described herein. Rather, the examples described herein are provided so that this disclosure will be thorough and complete and will fully convey the scope of this disclosure to those of ordinary skill in the art.

[0025] Here, it should be noted that the use of the term "may" with respect to an example or embodiment (e.g., what an example or embodiment may include or implement) means that there is at least one example or embodiment that includes or implements such a feature, and not all examples and embodiments are limited thereto.

[0026] Throughout the specification, when an element (such as a layer, region, or substrate) is described as being "on" another element, "connected to" another element, or "coupled to" another element, the element may be directly "on" the other element, directly "connected to" the other element, or directly "coupled to" the other element, or there may be one or more other elements intervening therebetween. In contrast, when an element is described as being "directly on" another element, "directly connected to" another element, or "directly coupled to" another element, there may be no other elements intervening therebetween.

[0027] As used herein, the term "and / or" includes any one of the listed related items and any combination of any two or more of them.

[0028] Although terms such as "first," "second," and "third" may be used herein to describe various components, elements, regions, layers, or portions, these components, elements, regions, layers, or portions are not limited by these terms. Rather, these terms are only used to distinguish one component, element, region, layer, or portion from another. Thus, a first component, first element, first region, first layer, or first portion referred to in the examples described herein may also be referred to as a second component, second element, second region, second layer, or second portion without departing from the teachings of the examples.

[0029] For ease of description, spatially relative terms such as "above", "upper", "below", and "lower" may be used herein to describe the relationship of one element to another as shown in the figures. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, an element described as "above" or "upper" relative to another element will then be "below" or "lower" relative to the other element. Thus, the term "above" encompasses both an orientation of "above" and "below" depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or at other orientations), and the spatially relative terms used herein will be interpreted accordingly.

[0030] The terms used herein are for the purpose of describing various examples only and are not intended to limit the disclosure. Unless the context clearly dictates otherwise, the singular forms are also intended to include the plural forms. The terms "comprising", "including", and "having" list the presence of the stated features, quantities, operations, components, elements, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0031] Due to manufacturing techniques and / or tolerances, the shapes shown in the figures may vary. Accordingly, the examples described herein are not limited to the specific shapes shown in the figures but include changes in shape that occur during manufacturing.

[0032] The features of the examples described herein may be combined in various ways that will be apparent after understanding the disclosure of this application. In addition, although the examples described herein have various configurations, other configurations will be apparent after understanding the disclosure of this application.

[0033] The figures may not be drawn to scale, and for clarity, illustration, and convenience, the relative sizes, proportions, and depictions of the elements in the figures may be exaggerated.

[0034] Subsequently, the examples are described in further detail with reference to the figures.

[0035] In the figures, the X direction may be defined as the second direction or the length direction, the Y direction may be defined as the third direction or the width direction, and the Z direction may be defined as the first direction, the stacking direction, or the thickness direction.

[0036] Multi-layer electronic component

[0037] Figure 1 is a schematic perspective view of a multi-layer electronic component according to an embodiment.

[0038] Figure 2 is along Figure 1Schematic cross-sectional view taken along line I-I'.

[0039] Figure 3 is Figure 2 an enlarged view of region P.

[0040] Figure 4 is an exploded perspective view schematically showing a body in which dielectric layers and internal electrodes are stacked.

[0041] Hereinafter, a multilayer electronic component according to an embodiment will be described in detail with reference to Figures 1 to 4 Detailed description of the multilayer electronic component according to the embodiment will be given.

[0042] A multilayer electronic component 100 according to an embodiment may include: a body 110 including dielectric layers 111 and internal electrodes 121 and 122, the internal electrodes 121 and 122 being alternately arranged and the dielectric layer 111 being interposed between the internal electrodes 121 and 122; and external electrodes 131 and 132 provided on the body and connected to the internal electrodes. At least one of the internal electrodes 121 and 122 has a greater thickness at end portions 121a and 122a in the longitudinal direction of the body than at its central portion. The central portion may extend away from the corresponding end portions 121a and 122a (or the external electrodes 131 and 132) in the longitudinal direction. The ratio t2 / t1 of the thickness t2 of at least one of the end portions 121a and 122a to the thickness t1 of the central portion satisfies 1.1 ≤ t2 / t1 ≤ 1.5. The respective end portions of each of the internal electrodes 121 and 122 may not overlap with adjacent internal electrodes.

[0043] In the body 110, the dielectric layers 111 and the internal electrodes 121 and 122 are alternately stacked.

[0044] Although the detailed shape of the body 110 is not particularly limited, as shown in the drawings, the body 110 may be formed in a hexahedral shape or the like. Due to the shrinkage of the ceramic powder contained in the body 110 during the firing process, although the body 110 does not have a perfect straight hexahedral shape, the body 110 may have a substantially hexahedral shape.

[0045] The body 110 may have: a first surface 1 and a second surface 2 that are opposite to each other in the thickness direction (Z direction), a third surface 3 and a fourth surface 4 that are connected to the first surface 1 and the second surface 2 and are opposite to each other in the longitudinal direction (X direction), and a fifth surface 5 and a sixth surface 6 that are connected to the first surface 1 and the second surface 2, are connected to the third surface 3 and the fourth surface 4, and are opposite to each other in the width direction (Y direction).

[0046] The plurality of dielectric layers 111 forming the body 110 are in a fired state, and adjacent dielectric layers 111 may be integrated with each other to such an extent that it is difficult to identify the boundary between the dielectric layers 111 without using a scanning electron microscope (SEM).

[0047] According to an embodiment, the raw material for forming the dielectric layer 111 is not particularly limited as long as sufficient capacitance can be obtained. For example, a barium titanate-based material, a lead composite perovskite-based material, a strontium titanate-based material, etc. can be used. The barium titanate-based material may include BaTiO3-based ceramic powder, and examples of the BaTiO3-based ceramic powder include those in which calcium (Ca), zirconium (Zr), etc. are partially solid-solved in BaTiO3 (Ba 1-x Ca x )TiO3, Ba(Ti 1-y Ca y )O3, (Ba 1-x Ca x )(Ti 1-y Zr y )O3 or Ba(Ti 1-y Zr y )O3.

[0048] According to an embodiment of the present disclosure, various ceramic additives, organic solvents, plasticizers, binders, dispersants, etc. can be added to the powder particles formed of a material such as barium titanate (BaTiO3) as a material for forming the dielectric layer 111 according to the use.

[0049] On the other hand, the thickness of the dielectric layer 111 does not need to be particularly limited.

[0050] However, when the dielectric layer is thinly formed to a thickness of less than 0.6 μm, for example, when the thickness of the dielectric layer is 0.41 μm or less, the increase in the short-circuit rate due to the radiation cracks caused by the volume expansion of the inner electrode may be more frequent.

[0051] As described below, according to an embodiment of the present disclosure, even when the dielectric layer and the inner electrode are very thin, since the radiation cracks caused by the volume expansion of the inner electrode can be effectively prevented, the reliability of the multilayer electronic component can be improved. Therefore, even when the thickness of the dielectric layer is 0.41 μm or less, sufficient reliability can be ensured.

[0052] Therefore, when the thickness of the dielectric layer 111 is 0.41 μm or less, the reliability improvement effect according to an embodiment of the present disclosure can be more significantly improved.

[0053] The thickness of the dielectric layer 111 may represent the average thickness of the dielectric layer 111 provided between the first inner electrode 121 and the second inner electrode 122.

[0054] The average thickness of the dielectric layer 111 can be measured by an image of the main body 110 obtained by scanning the length and thickness direction (L-T) cross-section of the main body 110 using a scanning electron microscope (SEM).

[0055] For example, using a length-thickness direction (L-T) cross-section cut in the central portion in the width direction of the main body 110, for any dielectric layer obtained from an image acquired by scanning this cross-section using a scanning electron microscope (SEM), the average value can be measured by measuring the thickness at 30 equally spaced points in the length direction.

[0056] The thickness of 30 equally spaced points can be measured in the capacitance formation portion A that represents the region where the first internal electrode 121 and the second internal electrode 122 overlap each other.

[0057] The capacitance formation portion A is provided inside the main body 110 and includes a first internal electrode 121 and a second internal electrode 122 that are arranged to face each other with a dielectric layer 111 interposed therebetween to form a capacitance. The main body 110 may further include covering portions 112 and 113 formed on the upper and lower portions of the capacitance formation portion.

[0058] In addition, the capacitance formation portion can contribute to the formation of the capacitance of the capacitor and can be formed by repeatedly stacking a plurality of first internal electrodes 121 and a plurality of second internal electrodes 122 with the dielectric layer 111 interposed between the first internal electrode 121 and the second internal electrode 122.

[0059] The upper covering portion 112 and the lower covering portion 113 can be formed by stacking a single dielectric layer or two or more dielectric layers on the upper surface and the lower surface of the capacitance formation portion in the thickness direction, respectively, and can be used to prevent damage to the internal electrodes caused by physical stress or chemical stress.

[0060] The upper covering portion 112 and the lower covering portion 113 may not include internal electrodes and may include the same material as that of the dielectric layer 111.

[0061] For example, the upper covering portion 112 and the lower covering portion 113 may contain a ceramic material, for example, may contain a barium titanate (BaTiO3)-based ceramic material.

[0062] In addition, the thickness of the covering portions 112 and 113 does not need to be particularly limited. However, in order to more easily achieve miniaturization and high capacitance of the multilayer electronic component, the thickness of the covering portions 112 and 113 can be 20 μm or less.

[0063] The internal electrodes 121 and 122 are alternately stacked with the dielectric layer 111 interposed between the internal electrodes 121 and 122.

[0064] The internal electrodes may include a first internal electrode 121 and a second internal electrode 122. The first internal electrode 121 and the second internal electrode 122 are alternately arranged to face each other, and a dielectric layer 111 of the main body 110 is interposed between the first internal electrode 121 and the second internal electrode 122, and the first internal electrode 121 and the second internal electrode 122 may be respectively exposed on a third surface 3 and a fourth surface 4 of the main body 110.

[0065] Referring to Figure 2 , the first internal electrode 121 is spaced apart from the fourth surface 4 and is exposed through the third surface 3, and the second internal electrode 122 is spaced apart from the third surface 3 and is exposed through the fourth surface 4.

[0066] In this case, the first internal electrode 121 and the second internal electrode 122 may be electrically separated from each other by the dielectric layer 111 provided therebetween.

[0067] Referring to Figure 4 , the main body 110 may be formed by alternately stacking a green sheet printed with the first internal electrode 121 and a green sheet printed with the second internal electrode 122 thereon and then firing the stacked sheets.

[0068] According to an embodiment, in at least one of the internal electrodes 121 and 122, end portions 121a and 122a of the internal electrode in the longitudinal direction of the main body 110 are thicker than a central portion, and a ratio t2 / t1 of a thickness t2 of each of the end portions 121a and 122a of the internal electrode in the longitudinal direction of the main body 110 to a thickness t1 of the central portion is controlled to satisfy 1.1 ≤ t2 / t1 ≤ 1.5.

[0069] At least one of the internal electrodes 121 and 122 has end portions 121a and 122a in the longitudinal direction of the main body 110, the thicknesses of the end portions 121a and 122a are greater than the thickness of the central portion thereof, and a ratio t2 / t1 of the thickness t2 of the end portions 121a and 122a to the thickness t1 of the central portion can be adjusted to satisfy 1.1 ≤ t2 / t1 ≤ 1.5, thereby preventing radiation cracks and improving the reliability of the multilayer electronic component.

[0070] Generally, since the dielectric layer and the internal electrodes are relatively thin, copper (Cu) diffuses into the internal electrodes during the firing of the external electrodes, and thus radiation cracks are frequently generated.

[0071] Radiation cracks caused by volume expansion of the internal electrodes lead to an increase in the short-circuit rate of the multilayer ceramic capacitor.

[0072] Radiation cracks generated due to the diffusion of copper (Cu) into the internal electrodes are caused by a difference in the diffusion coefficients of copper (Cu) and nickel (Ni) contained in the internal electrodes.

[0073] For example, according to the diffusion coefficient comparison table, the diffusion coefficient of copper (Cu) at 750 °C is approximately 100 times that of nickel (Ni).

[0074] As described above, due to the relatively large difference in the diffusion coefficients of copper (Cu) and nickel (Ni), the diffusion of copper (Cu) into nickel (Ni) is greater than the diffusion of nickel (Ni) into copper (Cu). Therefore, radiation cracks are generated by the volume expansion of the inner electrode.

[0075] In a multilayer ceramic capacitor of the prior art, copper (Cu) contained in the outer electrode frequently diffuses into the inner electrode containing nickel (Ni), which causes a major problem of volume expansion of the inner electrode.

[0076] In fact, in the case of a multilayer ceramic capacitor of the prior art, when measuring the ratio of the thickness of the end region of the inner electrode that is electrically connected to the outer electrode in the length direction of the main body to the thickness of the inner electrode measured in the central region of the main body, it can be seen that this ratio exceeds at least 1.5.

[0077] Thus, if the ratio of the thickness of the end region of the inner electrode in the length direction of the main body to the thickness of the inner electrode measured in the central region of the main body exceeds 1.5, there is a high possibility of radiation cracks occurring due to the volume expansion of the inner electrode.

[0078] To prevent radiation cracks at the ends of the inner electrode, research is being conducted to significantly reduce the diffusion of copper (Cu) while changing the paste composition and firing conditions of the outer electrode. However, due to the concentration gradient during firing, it may be difficult to effectively control the diffusion of copper (Cu).

[0079] However, according to an embodiment of the present disclosure, the ratio t2 / t1 of the thickness t2 of the ends 121a and 122a of at least one of the inner electrodes 121 and 122 to the thickness t1 of the central portion can satisfy 1.1 ≤ t2 / t1 ≤ 1.5, thereby preventing radiation cracks to improve the reliability of the multilayer electronic component.

[0080] In an embodiment of the present disclosure, a method of making the ratio t2 / t1 of the thickness t2 of the ends 121a and 122a of the inner electrodes 121 and 122 to the thickness t1 of the central portion satisfy 1.1 ≤ t2 / t1 ≤ 1.5 can be implemented by controlling the inner electrodes 121 and 122 to contain a Ni-Cu alloy.

[0081] Specifically, different from a multilayer ceramic capacitor of the prior art, the inner electrode contains a certain amount of copper (Cu) as well as nickel (Ni), rather than only containing nickel (Ni) as the conductive metal, thereby significantly reducing the diffusion of copper (Cu) into the inner electrode.

[0082] Specifically, by adjusting the content of copper (Cu) included in the inner electrodes 121 and 122, volume expansion of the ends 121a and 122a of the inner electrodes 121 and 122 in the longitudinal direction of the main body 110 can be prevented, thereby preventing radiation cracks.

[0083] Details of the amount of copper (Cu) included in the inner electrodes 121 and 122 will be described later.

[0084] If the ratio t2 / t1 of the thickness t2 of the ends 121a and 122a of the inner electrodes 121 and 122 to the thickness t1 of the central portion is less than 1.1, the radiation crack prevention effect is excellent. However, it may be difficult to achieve a thickness ratio of less than 1.1 due to the diffusion of copper (Cu) from the outer electrode to the inner electrode.

[0085] On the other hand, if the ratio t2 / t1 of the thickness t2 of the ends 121a and 122a of the inner electrodes 121 and 122 to the thickness t1 of the central portion of the inner electrodes 121 and 122 exceeds 1.5, similar to the prior art case, the volume expansion of the inner electrodes is severe. Therefore, defects such as radiation cracks may occur.

[0086] In the length-thickness cross-section of the main body 110, the thickness t1 of the central portions of the inner electrodes 121 and 122 and the thickness t2 of the ends 121a and 122a may mean the average thickness of the respective regions of the inner electrodes 121 and 122 stacked in the main body 110.

[0087] The thickness t1 of the central portions of the inner electrodes 121 and 122 and the thickness t2 of the ends 121a and 122a of the inner electrodes 121 and 122 can be measured by using an image obtained by scanning the length-thickness (L-T) cross-section of the main body 110 with a scanning electron microscope.

[0088] For example, the thickness t1 of the central portions of the inner electrodes 121 and 122 can be obtained by an average value provided by measuring the thickness of each of five points determined after determining five points including two points on the left and two points on the right with respect to a reference point (an inner electrode layer point at the intersection of the center line C in the longitudinal direction of the main body and the central portion of the corresponding inner electrode layer) as the center, in the inner electrode layer obtained from an image provided by scanning the length-thickness (L-T) cross-section of the main body 110 cut at the central portion in the width direction of the main body 110 by using a scanning electron microscope (SEM), where the five inner electrode layers include the upper two layers and the lower two layers and one inner electrode layer at the point where the center line in the longitudinal direction of the main body and the center line in the thickness direction intersect each other.

[0089] For example, in the case of the thickness t1 of the central portions of the inner electrodes 121 and 122, for the above five inner electrode layers, the thickness of one point is measured at the point where the center line C in the length direction of the inner electrode layer intersects the central portion of the corresponding inner electrode layer, and the thicknesses of the corresponding two points that are equidistant (each 500 nm) in the left-right direction based on the one point of the inner electrode layer. The thickness t1 can be determined by the average value of the thicknesses of a total of 25 points.

[0090] In the case of the thickness t2 of the end portions 121a and 122a of the inner electrodes 121 and 122, the thickness t2 can be obtained as an average value provided by: in the inner electrode layer obtained from an image provided by scanning the length-thickness (L-T) cross-section of the main body 110 cut at the central portion in the width direction of the main body 110 using a scanning electron microscope (SEM), on five inner electrode layers including the upper two layers and the lower two layers based on one inner electrode layer at the point where the center line C in the length direction of the main body and the center line in the thickness direction intersect each other, measuring the thicknesses of the corresponding two points of the end points of the inner electrode exposed in the length direction to contact the outer electrode and the points having a 500 nm interval inward from the end points to provide the average value.

[0091] For example, since the thicknesses of the corresponding two points of the end points of the inner electrodes exposed in the length direction to contact the outer electrode and the points having a 500 nm interval inward from the end points are measured respectively on the five inner electrode layers obtained as described above, the thickness t2 of the end portions 121a and 122a of the inner electrodes 121 and 122 can be determined by the average value of the thicknesses of a total of ten points.

[0092] According to an embodiment of the present disclosure, more specifically, the ratio t2 / t1 of the thickness t2 of the end portions 121a and 122a of at least one of the inner electrodes 121 and 122 to the thickness t1 of the central portion may satisfy 1.1 ≤ t2 / t1 ≤ 1.3.

[0093] At least one of the inner electrodes 121 and 122 satisfies that the ratio t2 / t1 of the thickness t2 of the end portions 121a and 122a to the thickness t1 of the central portion is 1.1 ≤ t2 / t1 ≤ 1.3. As a result, in the length direction of the main body 110, the effect of preventing radiation cracks by preventing the volume expansion of the end portions 121a and 122a of the inner electrodes 121 and 122 can be more excellent.

[0094] The ratio L2 / L1 of the length L2 in the length direction of the main body 110 of each of the end portions 121a and 122a of the inner electrodes 121 and 122 to the length L1 in the length direction of the main body 110 of each of the inner electrodes 121 and 122 may be 10% or less.

[0095] As described above, due to the diffusion of copper (Cu) from the outer electrode to the inner electrode, volume expansion occurs, and the length L2 in the longitudinal direction of the main body 110 of at least one of the ends 121a and 122a of the inner electrodes 121 and 122 may be less than or equal to 10% of the length L1 in the longitudinal direction of the corresponding inner electrodes 121 and 122 in the main body 110.

[0096] Since the diffusion distance of copper (Cu) from the outer electrode to the inner electrode is limited, copper does not diffuse deeply into the center of the inner electrode, and the ratio L2 / L1 of the length L2 in the longitudinal direction of the ends 121a and 122a of the inner electrodes 121 and 122 to the length L1 in the longitudinal direction of the inner electrodes 121 and 122 in the main body 110 may be 10% or less.

[0097] The length L1 in the longitudinal direction of the inner electrodes 121 and 122 and the length L2 in the longitudinal direction of the ends 121a and 122a of the inner electrodes 121 and 122 may represent the average lengths of the corresponding regions of the inner electrodes 121 and 122 stacked inside the main body 110 in the length-thickness direction cross-section of the main body 110.

[0098] The length L1 in the longitudinal direction of the inner electrodes 121 and 122 and the length L2 in the longitudinal direction of the ends 121a and 122a of the inner electrodes 121 and 122 can be measured by using an image obtained by scanning the length-thickness direction (L-T) cross-section of the main body 110 with SEM.

[0099] For example, the average value of the length L1 in the longitudinal direction of the inner electrodes 121 and 122 can be obtained by measuring the lengths of five inner electrode layers starting from the topmost inner electrode layer in the thickness direction, five inner electrode layers obtained from the central portion, and five inner electrode layers starting from the bottommost inner electrode layer on the inner electrode layer provided by the image obtained by scanning the length-thickness (L-T) cross-section cut in the central portion in the width direction of the main body 110 with SEM.

[0100] For example, since the lengths of five inner electrode layers starting from the topmost inner electrode layer in the thickness direction, five inner electrode layers obtained from the central portion, and five inner electrode layers starting from the bottommost inner electrode layer in the thickness direction are measured, the length L1 in the longitudinal direction of the inner electrodes 121 and 122 can be determined by the average value of 15 inner electrode layers.

[0101] The average value of the lengths L2 of the end portions 121a and 122a of the inner electrodes 121 and 122 in the longitudinal direction of the main body 110 can be obtained by measuring the lengths of the end portions 121a and 122a of the five inner electrode layers starting from the uppermost inner electrode layer in the thickness direction, the five inner electrode layers obtained from the central portion, and the five inner electrode layers starting from the lowermost inner electrode layer in the thickness direction in the longitudinal direction of the main body 110.

[0102] For example, in the case of the lengths L2 of the end portions 121a and 122a of the inner electrodes 121 and 122 in the longitudinal direction of the main body 110, since the lengths of the end portions 121a and 122a of the inner electrodes in the longitudinal direction of the main body 110 are measured with respect to the five inner electrode layers starting from the uppermost inner electrode layer in the thickness direction, the five inner electrode layers obtained from the central portion, and the five inner electrode layers starting from the lowermost inner electrode layer in the thickness direction, the length L2 can be determined by the average value of the lengths of the end portions 121a and 122a in the longitudinal direction of the main body 110.

[0103] According to an embodiment of the present disclosure, in the case of the inner electrodes 121 and 122, the distances from the two side boundary surfaces of the end portions 121a and 122a of the inner electrodes in the thickness direction of the main body 110 to the center of the end portions 121a and 122a of the inner electrodes 121 and 122 in the thickness direction of the main body 110 can be greater than the distances from the two side boundary surfaces of the central portions of the inner electrodes 121 and 122 in the thickness direction of the main body 110 to the center of the central portions of the inner electrodes 121 and 122 in the thickness direction.

[0104] As described above, the volume expansion of the end portions 121a and 122a in the longitudinal direction of the inner electrodes 121 and 122 is caused by the diffusion of copper (Cu) from the outer electrode to the inner electrode. Therefore, during the volume expansion, in the length-thickness cross-section of the main body 110, the expansion can occur in two directions rather than in one direction.

[0105] Therefore, in the length-thickness cross-section of the main body 110, the thickness of the central portions of the inner electrodes 121 and 122 does not increase in any one direction, but the thicknesses of the end portions 121a and 122a in the longitudinal direction of the inner electrodes 121 and 122 can increase in two directions in the thickness direction.

[0106] For example, in the internal electrodes 121 and 122, the distance from the two side boundary surfaces in the thickness direction of the main body 110 of the end portions 121a and 122a in the longitudinal direction to the center in the thickness direction of the end portions 121a and 122a of the internal electrodes 121 and 122 can be respectively greater than the distance from the two side boundary surfaces in the thickness direction of the central portions of the internal electrodes 121 and 122 to the center in the thickness direction of the central portions of the internal electrodes 121 and 122 in the thickness direction.

[0107] In an embodiment, the internal electrodes 121 and 122 may contain 80.0 wt% to 95.0 wt% of Ni and 5.0 wt% to 20.0 wt% of Cu. Therefore, the ratio t2 / t1 of the thickness t2 of the end portions 121a and 122a to the thickness t1 of the central portions of the internal electrodes 121 and 122 can be adjusted to satisfy 1.1 ≤ t2 / t1 ≤ 1.5, thereby preventing radiation cracks in the multilayer ceramic capacitor to improve reliability and the like.

[0108] If the content of copper (Cu) contained in the internal electrodes 121 and 122 is less than 5.0 wt%, the content of copper (Cu) is low. Therefore, it may be difficult to effectively suppress the diffusion of copper from the external electrode to the internal electrode. In this case, due to the volume expansion of the internal electrode, radiation cracks may increase.

[0109] Specifically, when the content of copper (Cu) contained in the internal electrodes 121 and 122 is greater than 10.0 wt% and less than or equal to 20.0 wt%, the diffusion of copper (Cu) from the external electrode to the internal electrode can be more effectively suppressed. In addition, the effect of reducing the occurrence of radiation cracks is excellent, and the reliability can be further improved.

[0110] On the other hand, if the Cu content is greater than 20.0 wt%, the shrinkage of the internal electrode in the thickness direction due to the addition of Cu is aggravated, which may cause the problem of reducing the capacitance of the multilayer ceramic capacitor due to the internal electrode being cut off.

[0111] According to an embodiment of the present disclosure, Ni and Cu contained in the internal electrodes 121 and 122 may be contained in the form of a Ni-Cu alloy.

[0112] By controlling the firing conditions and using Ni-Cu alloy powder and the like, Ni and Cu contained in the internal electrodes 121 and 122 can be contained in the form of an alloy.

[0113] Since Ni and Cu are contained in the form of a Ni-Cu alloy, the effect of adding Cu can be improved, and the Cu contained in the internal electrode can be uniformly distributed in the internal electrode.

[0114] According to an embodiment, the feature of the content of copper (Cu) in the end portions 121a and 122a in the longitudinal direction of the inner electrodes 121 and 122 may be that it is greater than the content of copper (Cu) in the central portions of the inner electrodes 121 and 122.

[0115] In an embodiment of the present disclosure, since the inner electrode contains copper (Cu) of greater than or equal to 5.0 wt% and less than or equal to 20.0 wt%, and copper (Cu) diffuses from the outer electrode to the inner electrodes 121 and 122, the content of copper (Cu) in the end portions 121a and 122a in the longitudinal direction of the inner electrodes 121 and 122 is greater than the content of copper (Cu) in the central portions of the inner electrodes 121 and 122.

[0116] On the other hand, the thickness of the inner electrodes 121 and 122 does not need to be particularly limited.

[0117] According to an embodiment, even when the dielectric layer and the inner electrode are very thin, since cracks caused by the volume expansion of the inner electrode can be effectively prevented to improve the reliability of the multilayer electronic component, sufficient reliability can be ensured even when the thickness of the inner electrodes 121 and 122 is 0.41 μm or less.

[0118] Therefore, when the thickness of the inner electrodes 121 and 122 is 0.41 μm or less, the reliability improvement effect according to the embodiment can be more significantly improved.

[0119] The thickness of the inner electrodes 121 and 122 may refer to the average thickness of the inner electrodes 121 and 122.

[0120] The average thickness of the inner electrodes 121 and 122 can be measured by using an image obtained by scanning the length-thickness direction (L-T) cross-section of the main body 110 with a scanning electron microscope (SEM).

[0121] For example, for the selected first inner electrode and second inner electrode obtained from an image provided by scanning the length and thickness direction (L-T) cross-section cut at the central portion of the main body 110 in the width (W) direction with SEM, the thicknesses of the selected first inner electrode 121 and second inner electrode 122 can be measured at 30 equally spaced points to measure the average value.

[0122] The outer electrodes 131 and 132 are provided on the main body 110 and connected to the inner electrodes 121 and 122.

[0123] As Figure 2 shown, the first outer electrode 131 and the second outer electrode 132 are respectively provided on the third surface 3 and the fourth surface 4 of the main body 110 to be respectively connected to the first inner electrode 121 and the second inner electrode 122.

[0124] In this embodiment, although the multi-layer electronic component 100 is described as having a structure with two outer electrodes 131 and 132, the number or shape of the outer electrodes 131 and 132 may be changed according to the shape of the inner electrodes 121 and 122 or other uses.

[0125] As materials for the outer electrodes 131 and 132, any material such as a metal may be used as long as it has conductivity, and its detailed material may be determined considering electrical characteristics, structural stability, etc. In addition, the outer electrodes 131 and 132 may have a multi-layer structure.

[0126] For example, the outer electrode 131 may include an electrode layer 131a provided on the main body 110 and a plating layer 131b formed on the electrode layer 131a, and the outer electrode 132 may include an electrode layer 132a provided on the main body 110 and a plating layer 132b formed on the electrode layer 132a.

[0127] As a more detailed example of the electrode layers 131a and 132a, the electrode layers 131a and 132a may be fired electrodes including a conductive metal and glass, or resin-based electrodes including a conductive metal and resin.

[0128] In addition, the electrode layers 131a and 132a may have a form in which a fired electrode and a resin-based electrode are sequentially formed on the main body. In addition, the electrode layers 131a and 132a may be formed by transferring a sheet including a conductive metal onto the main body, or may be formed by transferring a sheet including a conductive metal onto a fired electrode.

[0129] As the conductive metal included in the electrode layers 131a and 132a, a material having excellent conductivity may be used and there is no particular limitation. For example, the conductive metal may be one or more of nickel (Ni), copper (Cu), and their alloys.

[0130] The plating layers 131b and 132b are used to improve mounting characteristics. The type of the plating layers 131b and 132b is not particularly limited, and may be a plating layer including at least one of Ni, Sn, Pd, and their alloys, and may be formed of multiple layers.

[0131] As a more detailed example of the plating layers 131b and 132b, the plating layers 131b and 132b may be Ni plating layers or Sn plating layers, may have a structure in which Ni plating layers and Sn plating layers are sequentially formed on the electrode layers 131a and 132a, and may have a structure in which Sn plating layers, Ni plating layers, and Sn plating layers are sequentially formed. In addition, the plating layers 131b and 132b may include multiple Ni plating layers and / or multiple Sn plating layers.

[0132] The size of the multi-layer electronic component 100 does not need to be particularly limited.

[0133] However, in order to achieve miniaturization and high capacitance simultaneously, the thicknesses of the dielectric layer and the internal electrodes should be reduced to increase the number of stacked layers. Therefore, in a multilayer electronic component having a size of 0402 (length × width, 0.4 mm × 0.2 mm) or less, the reliability improvement effect according to the embodiment can be further enhanced.

[0134] Therefore, when the distance between the third surface and the fourth surface of the main body is defined as L and the distance between the fifth surface and the sixth surface is defined as W, L can be 0.4 mm or less, and W can be 0.2 mm or less. For example, a multilayer electronic component having a size of 0402 (length × width, 0.4 mm × 0.2 mm) or less can be provided.

[0135] Hereinafter, a method of manufacturing the multilayer electronic component 100 according to the embodiment will be described.

[0136] First, a plurality of green ceramic sheets are prepared.

[0137] The green ceramic sheets are used to form the dielectric layer 111 of the main body 110. A slurry is prepared by mixing ceramic powder, polymer, and solvent, and the slurry is formed into a sheet having a predetermined thickness by a method such as a doctor blade method.

[0138] Subsequently, internal electrodes are formed by printing a conductive paste for the internal electrodes to a predetermined thickness (for example, a thickness of 0.41 μm or less) on at least one surface of each green ceramic sheet.

[0139] The conductive paste for the internal electrodes can be formed to contain 80.0 wt% to 95.0 wt% of Ni and 5.0 wt% to 20.0 wt% of Cu. For example, Ni powder and Cu powder can be mixed, or Ni-Cu alloy powder can be included to form the conductive paste for the internal electrodes.

[0140] As a printing method of the conductive paste for the internal electrodes, a screen printing method or a gravure printing method can be used.

[0141] Refer to Figure 4 , a plurality of green ceramic sheets are stacked by alternately stacking the green ceramic sheets printed with the first internal electrode 121 and the green ceramic sheets printed with the second internal electrode 122 in the stacking direction. The green ceramic sheets formed with internal electrodes can be pressed to form a laminate.

[0142] In addition, cover portions 112 and 113 can be formed by stacking at least one green ceramic sheet on the upper and lower portions of the laminate.

[0143] The cover portions 112 and 113 can have the same composition as the dielectric layer 111 located inside the laminate, and the cover portions 112 and 113 are different from the dielectric layer 111 in that the cover portions 112 and 113 do not include internal electrodes.

[0144] Thereafter, the laminate is cut into respective regions corresponding to one capacitor and sliced, and then fired at a high temperature to complete the main body 110.

[0145] Thereafter, the first external electrode 131 and the second external electrode 132 may be formed to cover the exposed portions of the first internal electrode and the second internal electrode exposed on both sides of the main body 110, thereby being electrically connected to the first internal electrode and the second internal electrode.

[0146] At this time, if necessary, the surfaces of the first external electrode 131 and the second external electrode 132 may be plated with nickel or tin.

[0147] (Examples and comparative examples)

[0148] In a sample sheet including internal electrodes formed by using a conductive paste for internal electrodes to which Cu is added at a certain ratio, the thickness ratio of the end portion to the central portion and the corresponding short - circuit rate were compared between a comparative example without Cu and Examples 1 to 4 in which Cu was added at a predetermined ratio.

[0149] In the comparative example, Cu was not added to the conductive paste for internal electrodes, and the average thickness ratio of the end portion to the central portion was measured to be 1.56. In this case, the short - circuit rate was 30%, indicating a high defect rate and reduced reliability.

[0150] Samples 1 to 4 are Examples 1 to 4 of the present disclosure, and contain 5 wt% of Cu (Example 1), 10 wt% of Cu (Example 2), 15 wt% of Cu (Example 3), and 20 wt% of Cu (Example 4) in the conductive paste for internal electrodes, respectively.

[0151] In the case of Example 1, the average thickness ratio of the end portion to the central portion was 1.42 and the short - circuit rate was 28%. In Example 2, the average thickness ratio of the end portion to the central portion was 1.33 and the short - circuit rate was 20%. In this case, it can be seen that the short - circuit rate is low, thus improving reliability.

[0152] Next, in Example 3, the average thickness ratio of the end portion to the central portion was 1.21 and the short - circuit rate was 15%. In Example 4, the average thickness ratio of the end portion to the central portion was 1.12 and the short - circuit rate was 11%. It was found that the short - circuit ratio was low and reliability was improved.

[0153] Specifically, in Examples 3 and 4, the content of copper (Cu) included in the internal electrodes 121 and 122 is greater than 10.0 wt% and less than or equal to 20.0 wt%, and copper diffusion from the external electrode to the internal electrode can be more effectively suppressed. Therefore, it can be seen that the effect of reducing the generation of radiation cracks is excellent, and the reliability can be further improved.

[0154] As described above, according to an embodiment, at least one of the inner electrodes is thicker at an end portion in the longitudinal direction of the main body than at a central portion of the inner electrode, and a ratio (t2 / t1) of a thickness t2 of the end portion to a thickness t1 of the central portion satisfies 1.1 ≤ t2 / t1 ≤ 1.5, thereby preventing radiation cracks to improve reliability of the multilayer electronic component.

[0155] Although the present disclosure includes specific examples, it will be apparent to those of ordinary skill in the art that various changes in form and detail may be made in these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein will be considered only in a descriptive sense and not for purposes of limitation. The description of a feature or aspect in each example will be considered applicable to a similar feature or aspect in other examples. Appropriate results may be obtained if the described techniques are performed in a different order, and / or if components in the described systems, architectures, devices, or circuits are combined in a different manner, and / or replaced or supplemented by other components or their equivalents. Accordingly, the scope of the present disclosure is not limited by the specific embodiments, but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents will be construed as being included in the present disclosure.

Claims

1. A multilayer electronic component, comprising: A body including a dielectric layer and internal electrodes, the internal electrodes being stacked alternately and the dielectric layer being interposed between the internal electrodes; And External electrodes disposed on the body and connected to the internal electrodes, wherein at least one of the internal electrodes is thicker at an end in the longitudinal direction of the body than at a central portion of the internal electrode, and a ratio t2 / t1 of a thickness t2 of the end to a thickness t1 of the central portion satisfies 1.1 ≤ t2 / t1 ≤ 1.5, and wherein a content of copper contained in the internal electrodes is greater than 10.0 wt% and less than or equal to 20.0 wt%.

2. The multi-layer electronic component according to claim 1, wherein, A ratio t2 / t1 of the thickness t2 of the end of the at least one of the internal electrodes to the thickness t1 of the central portion satisfies 1.1 ≤ t2 / t1 ≤ 1.

3.

3. The multi-layer electronic component according to claim 1, wherein, A ratio L2 / L1 of a length L2 of the end of the internal electrode in the longitudinal direction of the body to a length L1 of the internal electrode in the longitudinal direction of the body is 10% or less.

4. The multi-layer electronic component according to any one of claims 1-3, wherein, The internal electrodes further contain nickel in an amount of greater than or equal to 80.0 wt% and less than 90.0 wt%.

5. The multilayer electronic component according to claim 4, wherein, The nickel and the copper are contained in the form of a nickel-copper alloy.

6. The multi-layer electronic component according to claim 4, wherein A content of copper contained in the end of the internal electrode is greater than a content of copper contained in the central portion of the internal electrode.

7. The multilayer electronic component according to claim 1, wherein, The multilayer electronic component has a length of 0.4 mm or less and a width of 0.2 mm or less.

8. The multilayer electronic component according to claim 1, wherein, The internal electrodes have an average thickness of 0.41 μm or less, and / or the dielectric layer has an average thickness of 0.41 μm or less.

9. A multilayer electronic component, comprising: External electrodes disposed on opposite side surfaces of the body of the multilayer electronic component in the longitudinal direction; And Internal electrodes having opposite polarities and disposed alternately with a dielectric layer interposed between the internal electrodes, each of the internal electrodes having an end in contact with a corresponding external electrode and a central portion extending away from the end in the longitudinal direction, wherein a ratio t2 / t1 of a thickness t2 of at least one of the ends to a thickness t1 of a corresponding central portion satisfies 1.1 ≤ t2 / t1 ≤ 1.5, and wherein a content of copper contained in the internal electrodes is greater than 10.0 wt% and less than or equal to 20.0 wt%.

10. The multilayer electronic component according to claim 9, wherein, A ratio L2 / L1 of a length L2 of at least one of the ends to a length L1 of a corresponding internal electrode is 0.1 or less.

11. The multilayer electronic component according to claim 9 or 10, wherein, A content of copper in at least one of the ends is greater than a content of copper in a corresponding central portion.

12. The multi-layer electronic component according to claim 9, wherein, The internal electrodes have an average thickness of 0.41 μm or less, and / or the dielectric layer has an average thickness of 0.41 μm or less.

13. A multilayer electronic component, comprising: A body including: A first internal electrode exposed through a first side surface of the body, A second internal electrode exposed through a second side surface of the body opposite to the first side surface in the longitudinal direction, and A dielectric layer interposed between each pair of consecutive first and second internal electrodes, the first internal electrode, the second internal electrode, and the dielectric layer being stacked in a thickness direction, A first outer electrode and a second outer electrode are respectively disposed on the first side surface and the second side surface. Wherein, each of the first inner electrode and the second inner electrode has an end portion that does not overlap with an adjacent inner electrode and a central portion that extends away from the corresponding outer electrode. The ratio t2 / t1 of the thickness t2 of at least one of the end portions to the thickness t1 of the corresponding central portion satisfies 1.1 ≤ t2 / t1 ≤ 1.5, and the content of copper contained in the first inner electrode and the second inner electrode is greater than 10.0 wt% and less than or equal to 20.0 wt%.

14. The multilayer electronic component according to claim 13, wherein, The distances from the two side boundary surfaces in the thickness direction of at least one of the end portions to the center are respectively greater than the distances from the two side boundary surfaces in the thickness direction of the corresponding central portion to the center.

15. The multi-layer electronic component according to claim 13, wherein, The first inner electrode and the second inner electrode contain a nickel-copper alloy.

16. A multilayer electronic component, comprising: a body including a dielectric layer and inner electrodes, the inner electrodes being alternately stacked and the dielectric layer being interposed between the inner electrodes; and outer electrodes disposed on the body and connected to the inner electrodes, wherein, at least one of the inner electrodes is thicker at an end portion in the length direction of the body than at a central portion of the inner electrode, and the content of copper contained in the inner electrode is greater than 10.0 wt% and less than or equal to 20.0 wt%.

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