Multilayer capacitor

Abstract

The present disclosure provides a multilayer capacitor including: a body including a dielectric layer stacked in a first direction and a plurality of internal electrodes disposed to face each other with the dielectric layer interposed therebetween; and an external electrode disposed on the main body and connected to the internal electrode. At least one of the plurality of internal electrodes includes: a capacitance portion disposed to overlap an adjacent internal electrode; and a lead-out portion extending from the capacitance portion to be connected to the external electrode, including a protruding portion protruding from one surface of the body in a second direction perpendicular to the first direction, and including a portion having a thickness in the first direction greater than a thickness of the capacitance portion in the first direction, and wherein the lead-out portion includes a protruding portion protruding from one surface of the body in a second direction perpendicular to the first direction. The ratio of the length, in the second direction, of the protruding part to the thickness of the capacitor part is larger than or equal to 0.07 and smaller than 0.1.

Description

Technical Field

[0001] The present disclosure relates to a multilayer capacitor. Background Art

[0002] Multilayer capacitors are chip capacitors mounted on printed circuit boards of various electronic products such as video devices, computers, smart phones, mobile phones, etc. to charge or discharge.

[0003] Multilayer capacitors are used as components of various electronic devices because of their advantages of small size, high capacity, and easy installation. As components of electronic devices have become smaller recently, demands for miniaturization and high capacity of multilayer capacitors have increased.

[0004] As the miniaturization and high capacity of multilayer capacitors progress, the internal electrodes are required to be thinner. Therefore, there is a problem that the thickness of the portion where the internal electrodes of the body do not overlap is reduced, and the reliability is reduced. Summary of the invention

[0005] The present disclosure provides a multilayer capacitor which can improve reliability, can improve connectivity between inner and outer electrodes, and can reduce the risk of delamination.

[0006] Furthermore, the multilayer capacitor according to the present disclosure can reduce the risk of radiation cracks.

[0007] However, the problems to be solved by the present disclosure are not limited to the above-mentioned problems and can be expanded in various ways within the scope of the technical concept included in the present disclosure.

[0008] The multilayer capacitor according to the present disclosure includes: a main body including a dielectric layer and a plurality of inner electrodes stacked in a first direction, the plurality of inner electrodes being arranged to face each other, and the dielectric layer being interposed between the plurality of inner electrodes; and an outer electrode arranged on the main body and connected to the inner electrode in a second direction perpendicular to the first direction. At least one of the plurality of inner electrodes includes: a capacitor portion arranged to overlap with an adjacent inner electrode; and a lead portion extending from the capacitor portion to connect to the outer electrode, including a protrusion protruding from one surface of the main body in a second direction perpendicular to the first direction, and including a portion having a thickness along the first direction greater than a thickness of the capacitor portion along the first direction, and wherein a ratio of a length of the protrusion along the second direction to a thickness of the capacitor portion is within a range of greater than or equal to 0.07 and less than 0.1.

[0009] The lead-out portion may include a portion whose thickness increases in the first direction toward an outside of the body in the second direction.

[0010] The thickness of the portion of the lead-out portion where the thickness increases in the first direction gradually increases toward the outside of the body in the second direction.

[0011] The lead-out portion may further include a portion having a constant thickness along the first direction.

[0012] The protrusion may include a portion having a constant thickness along the first direction.

[0013] The lead-out portion may include a portion whose thickness in the first direction increases in two opposite directions in the first direction toward an outside of the body in the second direction.

[0014] The lead-out portion may include a portion whose thickness in the first direction increases in one direction in the first direction toward an outside of the body in the second direction.

[0015] A ratio of a maximum thickness of the lead portion along the first direction to an average thickness of the capacitor portion along the first direction may be in a range of greater than 1.2 and less than 2.0.

[0016] The protrusion may be covered by the outer electrode.

[0017] The body may include a first surface and a second surface opposite to each other in the first direction, a third surface and a fourth surface opposite to each other in the second direction, and a fifth surface and a sixth surface opposite to each other in a third direction perpendicular to the first direction and the second direction, the external electrode may include a first external electrode and a second external electrode, the plurality of internal electrodes may include first internal electrodes and second internal electrodes alternately arranged, the dielectric layer is interposed between the first internal electrode and the second internal electrode, the first internal electrode may include a first capacitor portion and a first lead-out portion, the first lead-out portion extending from the first capacitor portion to be connected to the first external electrode and including a first protrusion protruding from the third surface of the body, and the second internal electrode may include a second capacitor portion and a second lead-out portion, the second capacitor portion overlapping the first capacitor portion in the first direction, the second lead-out portion extending from the second capacitor portion to be connected to the second external electrode and including a second protrusion protruding from the fourth surface of the body.

[0018] The first protrusion may be covered by the first external electrode, and the second protrusion may be covered by the second external electrode.

[0019] The external electrode may include: a conductive layer disposed on a surface of the body and connected to the plurality of internal electrodes; and a plating layer disposed on the conductive layer.

[0020] A thickness of the protrusion portion along the first direction may be greater than a thickness of the capacitor portion along the first direction.

[0021] The protrusion may be a thickest portion of the at least one inner electrode among the plurality of inner electrodes.

[0022] The length of the protrusion may be in the range of 28 nm to 40 nm.

[0023] According to the multilayer capacitor of the present disclosure, the reliability can be improved by improving the thickness of the inner electrode, the connectivity between the inner electrode and the outer electrode can be improved, and the delamination can be prevented. In addition, the multilayer capacitor of the present disclosure can reduce the risk of radiation cracks. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a perspective view schematically showing a multilayer capacitor according to an embodiment of the present disclosure.

[0025] Figure 2 is along Figure 1 A cross-sectional view taken along line II-II'.

[0026] Figure 3 yes Figure 2 An enlarged cross-sectional view of part A.

[0027] Figure 4 yes Figure 2 An enlarged cross-sectional view of part B.

[0028] Figure 5 is shown along Figure 1 A cross-sectional view of a multilayer capacitor according to a modified example taken along line II-II' in FIG.

[0029] Figure 6 is shown along Figure 1 0 is a cross-sectional view of a multilayer capacitor according to another modified example taken along line II-II' in FIG.

[0030] Figure 7 is shown along Figure 1 0 is a cross-sectional view of a multilayer capacitor according to another modified example taken along line II-II' in FIG. DETAILED DESCRIPTION

[0031] The present disclosure will be described more fully below with reference to the accompanying drawings, in which embodiments of the present disclosure are shown. The drawings and descriptions are considered to be illustrative rather than restrictive in nature. Throughout the specification, similar reference numerals represent similar elements. In the accompanying drawings, for ease of description, the size and thickness of each element are arbitrarily shown, and the present disclosure is not necessarily limited to the sizes and thicknesses shown in the accompanying drawings.

[0032] In addition, the drawings are only for facilitating the understanding of the embodiments disclosed in this specification, and the technical concepts disclosed in this specification are not limited by the drawings, and all changes included in the spirit and technical scope of the present disclosure should be understood to include equivalent solutions or alternative solutions.

[0033] Terms including ordinal numbers such as "first", "second", etc. may be used to describe various constituent elements, but the constituent elements are not limited by the terms. The terms are used only for the purpose of distinguishing one constituent element from another constituent element.

[0034] It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "over" another element, the element may be directly on the other element, or intervening elements may also be present. Conversely, when an element is referred to as being "directly on" another element, there are no intervening elements. Furthermore, throughout the specification, the words "on" or "over" a target element will be understood as being disposed above or below the target element, and not necessarily as being disposed on the "upper side" based on a direction opposite to gravity.

[0035] In the present application, terms such as "include" or "have" are intended to indicate the presence of features, numbers, steps, operations, constituent elements, components, or combinations thereof described in the specification, but should be understood as not excluding the presence or addition of one or more other features, numbers, steps, operations, constituent elements, components, or combinations thereof. In addition, unless explicitly described to the contrary, the word "include" and variations such as "comprises" or "comprising" will be understood to imply the inclusion of the elements but not the exclusion of any other elements.

[0036] Furthermore, throughout the specification, the phrase "on a plane" refers to viewing a target portion from above, and the phrase "in cross section" refers to viewing a cross section obtained by vertically cutting the target portion from the side.

[0037] Throughout the specification, when it is described that a component is “coupled” to another component, the component may be “directly or physically connected” to the other component, or may be “indirectly or non-contactly connected” to the other component via a third component.

[0038] Throughout the specification, when a component is described as being “connected” to another component, the component may be “directly connected” to the other component, may be “connected” to the other component through a third component, or may be physically connected to the other component or electrically connected to the other component, and although various parts may be represented by different names according to positions or functions, various parts that are substantially integrated may be connected to each other.

[0039] In the following, the direction of the body 110 is defined to clearly describe the embodiments of the present disclosure. The x, y, and z shown in the drawings represent the length direction, width direction, and thickness direction of the body 110, respectively. Here, the z-axis direction (thickness direction, first direction) may be a direction perpendicular to the wide surface (main surface) of the sheet-like constituent element. For example, the z-axis direction (thickness direction) may be used as the same concept as the stacking direction of the stacked dielectric layer 111. The x-axis direction (length direction, second direction) may be a direction extending parallel to the wide surface (main surface) of the sheet-like constituent element, and may be a direction substantially perpendicular to the z-axis direction (thickness direction). For example, the x-axis direction (length direction) may be a direction in which the first external electrode 130 and the second external electrode 140 are opposite to each other. The y-axis direction (width direction, third direction) may be a direction extending parallel to the wide surface (main surface) of the sheet-like constituent element, and may be a direction substantially perpendicular to the z-axis direction (thickness direction) and the x-axis direction (length direction), and the length of the sheet-like constituent element in the x-axis direction (length direction) may be greater than the width of the sheet-like constituent element in the y-axis direction (width direction).

[0040] Therefore, the first direction, which is the direction in which the dielectric layer 111 and the first and second internal electrodes 121 and 122 are stacked, may be the z-axis direction (thickness direction), and the second and third directions, which are perpendicular to the first direction and perpendicular to each other, may be the x-axis direction (length direction) and the y-axis direction (width direction), respectively.

[0041] Figure 1 is a perspective view schematically showing a multilayer capacitor according to an embodiment of the present disclosure, and Figure 2 is along Figure 1 A cross-sectional view taken along line II-II'.

[0042] Reference Figure 1 and Figure 2 , the multilayer capacitor 100 according to the present embodiment includes a body 110 and first and second external electrodes 130 and 140 .

[0043] The body 110 may include a plurality of dielectric layers 111 , and a plurality of first internal electrodes 121 and a plurality of second internal electrodes 122 alternately disposed in the z-axis direction with the dielectric layers 111 interposed therebetween.

[0044] The body 110 may be formed by stacking a plurality of dielectric layers 111 in the z-axis direction and then firing the stacked dielectric layers, and adjacent dielectric layers 111 may be integrated to the extent that boundaries between adjacent dielectric layers 111 are difficult to identify without using a scanning electron microscope (SEM).

[0045] The body 110 may have a thickness of a predetermined size along the z-axis direction, a length of a predetermined size along the x-axis direction, and a width of a predetermined size along the y-axis direction, and may have a substantially hexahedral shape. However, the shape and size of the body 110 and the number of stacked dielectric layers 111 are not limited to the shapes, sizes, and numbers shown in the drawings of the present disclosure.

[0046] For the convenience of describing the present embodiment, two surfaces of the body 110 opposite to each other in the z-axis direction are defined as a first surface S1 and a second surface S2, two surfaces connected to the first surface S1 and the second surface S2 and opposite to each other in the x-axis direction are defined as a third surface S3 and a fourth surface S4, and two surfaces connected to the first surface S1 and the second surface S2 and the third surface S3 and the fourth surface S4 and opposite to each other in the y-axis direction are defined as a fifth surface S5 and a sixth surface S6. In addition, in the present embodiment, the mounting surface of the multilayer capacitor 100 may be the first surface S1 of the body 110.

[0047] The dielectric layer 111 may include a ceramic material having a high dielectric constant. For example, the dielectric layer 111 may include barium titanate (BaTiO 3 )-based ceramic material or strontium titanate (SrTiO 3 )-based ceramic material, but the present disclosure is not limited thereto as long as sufficient capacitance can be obtained.

[0048] In addition, ceramic additives, organic solvents, plasticizers, binders, dispersants, etc. may be further added together with the ceramic powder to the ceramic material for preparing the dielectric layer 111. For example, transition metal oxides, transition metal carbides, rare earth elements, magnesium (Mg), aluminum (Al), etc. may be used as ceramic additives.

[0049] The main body 110 may include an effective area and an upper cover 112 and a lower cover 113. The effective area is a portion that contributes to forming the capacitance of the capacitor. The upper cover 112 and the lower cover 113 are respectively formed at the upper and lower portions of the effective area in the z-axis direction. The upper cover 112 and the lower cover 113 are edge portions of the main body 110 in the z-axis direction.

[0050] The upper cover 112 and the lower cover 113 may have the same material and configuration as those of the dielectric layer 111 , except that the upper cover 112 and the lower cover 113 do not include an inner electrode.

[0051] The upper cover 112 and the lower cover 113 may be formed by stacking a single dielectric layer or two or more dielectric layers along the z-axis direction on the upper and lower surfaces of the active region. Basically, the upper cover 112 and the lower cover 113 may be used to prevent the first and second internal electrodes 121 and 122 from being damaged due to physical or chemical stress.

[0052] The first internal electrode 121 and the second internal electrode 122 may be electrodes having different polarities, and the first internal electrode 121 and the second internal electrode 122 may be alternately disposed in the z-axis direction with the dielectric layer 111 interposed therebetween. One end of the first internal electrode 121 and one end of the second internal electrode 122 may be exposed from the third surface S3 and the fourth surface S4 of the body 110, respectively. In addition, one end of the first internal electrode 121 and one end of the second internal electrode 122 may protrude from the third surface S3 and the fourth surface S4 of the body 110, respectively.

[0053] The first and second internal electrodes 121 and 122 may be electrically insulated from each other by a dielectric layer 111 disposed between the first and second internal electrodes 121 and 122 .

[0054] Ends of the first inner electrode 121 and the second inner electrode 122 respectively exposed through the third surface S3 and the fourth surface S4 of the body 110 may be respectively electrically connected to the first outer electrode 130 and the second outer electrode 140 respectively disposed on the third surface S3 and the fourth surface S4 of the body 110 to be described below. Therefore, it is possible to improve the bonding strength between the inner and outer electrodes, reduce contact defects, and prevent the capacity of the multilayer capacitor 100 from being reduced.

[0055] In addition, the material forming the first internal electrode 121 and the second internal electrode 122 is not particularly limited. For example, the first internal electrode 121 and the second internal electrode 122 may be formed using a conductive paste made of one or more of a noble metal material (such as platinum (Pt), palladium (Pd), a palladium-silver (Pd-Ag) alloy, etc.), nickel (Ni), and copper (Cu). Here, the printing method of the conductive paste may be a screen printing method, a gravure printing method, etc., but the present disclosure is not limited thereto.

[0056] The first internal electrode 121 may include a first capacitor portion 121a and a first lead portion 121b. The first capacitor portion 121a may be a portion disposed to be spaced apart from the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6 of the body 110, and may be a portion that contributes to the capacitance of the capacitor. The first lead portion 121b may be a portion extending from the first capacitor portion 121a to be connected to the first external electrode 130. The first lead portion 121b may extend from the first capacitor portion 121a to protrude from the third surface S3 of the body 110. The first lead portion 121b may include a first protrusion 121b1 protruding from the third surface S3 of the body 110 in the x-axis direction.

[0057] The second inner electrode 122 may include a second capacitor portion 122a and a second lead portion 122b. The second capacitor portion 122a may be a portion disposed to be spaced apart from the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6 of the body 110, and may be a portion that contributes to the capacitance of the capacitor. The second lead portion 122b may extend from the second capacitor portion 122a to be connected to the second outer electrode 140. The second lead portion 122b may extend from the second capacitor portion 122a to protrude from the fourth surface S4 of the body 110. The second lead portion 122b may include a second protrusion 122b1 protruding from the fourth surface S4 of the body 110 in the x-axis direction.

[0058] As described above, the first and second internal electrodes 121 and 122 may include the first and second protrusions 121 b 1 and 122 b 1 protruding to the outside of the body 110 , so that contact of the internal electrodes with the external electrodes may be improved.

[0059] The first lead-out portion 121 b and the second lead-out portion 122 b may be disposed to be offset from each other in the length direction of the body 110 to be exposed at both ends along the length direction of the body 110 , respectively.

[0060] If a predetermined voltage is applied to the first and second external electrodes 130 and 140 , charges are accumulated between the first and second internal electrodes 121 and 122 .

[0061] Here, the capacitance of the multilayer capacitor 100 is proportional to an overlapping area in which the first capacitance portion 121 a of the first internal electrode 121 and the second capacitance portion 122 a of the second internal electrode 122 overlap each other in the z-axis direction in the active area of ​​the body 110 .

[0062] The first external electrode 130 and the second external electrode 140 may be provided with voltages having different polarities, may be respectively disposed at both ends of the body 110 in the x-axis direction, and may be respectively electrically connected to the exposed portion of the first internal electrode 121 and the exposed portion of the second internal electrode 122. For example, the first external electrode 130 may be electrically connected to the plurality of first lead-out portions 121 b, and the second external electrode 140 may be electrically connected to the plurality of second lead-out portions 122 b (to be described later).

[0063] The first external electrode 130 may be disposed on the surface of the body 110. The first external electrode 130 may include a conductive layer (not shown) connected to the plurality of first internal electrodes 121 and at least one plating layer (not shown) disposed on the conductive layer. The plating layer may be disposed to cover the conductive layer. In addition, the second external electrode 140 may be disposed on the surface of the body 110. The second external electrode 140 may include a conductive layer (not shown) connected to the plurality of second internal electrodes 122 and at least one plating layer (not shown) disposed on the conductive layer. The plating layer may be disposed to cover the conductive layer.

[0064] The conductive layer may include a connection portion and a band portion. The connection portion may be provided on the third surface S3 or the fourth surface S4 of the body 110 and may be connected to a protrusion of the first internal electrode 121 or the second internal electrode 122. The band portion may include a portion extending from the connection portion to a portion of the first surface S1 of the body 110. The band portion may also extend to a portion of the fifth surface S5 and a portion of the sixth surface S6 of the body 110 and a portion of the second surface S2 to improve adhesion strength.

[0065] The conductive layer may include at least one of copper (Cu) and silver (Ag), and may further include glass, epoxy resin, etc. The conductive layer may be formed by applying a conductive paste including a metal and firing the applied conductive paste.

[0066] The plating layer may include nickel (Ni), phosphorus (P) or palladium (Pd). In addition, the plating layer may be formed by electroless plating. The plating characteristics of electroless plating may not be significantly different from those of electrolytic plating, and the plating layer formed by electroless plating may have better corrosion resistance than the film formed by electrolytic plating and may grow substantially equally at each position to have a uniform plating thickness. In addition, since electroless plating is only performed on the object to be plated without false plating flakes, it is easier to prepare for plating and screen defective plated objects after plating.

[0067] In the following, reference will be made to Figures 2 to 4 The structures of the first and second internal electrodes 121 and 122 are described in detail.

[0068] Figure 3 yes Figure 2 An enlarged cross-sectional view of part A of Figure 4 yes Figure 2 An enlarged cross-sectional view of part B.

[0069] Reference Figures 2 to 4 , the first lead portion 121b may be disposed at one end of the first capacitor portion 121a. The first lead portion 121b may include a portion whose thickness along the z-axis direction is thicker than the thickness L1 of the first capacitor portion 121a along the z-axis direction. The thickness L2 of the first lead portion 121b along the z-axis direction may be greater than the thickness L1 of the first capacitor portion 121a along the z-axis direction. In addition, the second lead portion 122b may be disposed at one end of the second capacitor portion 122a. The second lead portion 122b may include a portion whose thickness along the z-axis direction is thicker than the thickness L1 of the second capacitor portion 122a along the z-axis direction. The thickness L2 of the second lead portion 122b along the z-axis direction may be greater than the thickness L1 of the second capacitor portion 122a along the z-axis direction.

[0070] The thickness L1 of each of the first capacitor 121a and the second capacitor 122a in the z-axis direction can be: in the xz cross section of the center point of the y-axis direction passing through the multilayer capacitor 100, the length of any line segment connected to its upper surface from a point of the lower surface of each of the first capacitor 121a and the second capacitor 122a, or the arithmetic mean of the lengths of multiple line segments connected to its upper surface from a point of the lower surface of each of the first capacitor 121a and the second capacitor 122a. The above-mentioned multiple line segments can be 5 or more line segments arranged at equal intervals. The thickness L1 of each of the first capacitor 121a and the second capacitor 122a in the z-axis direction can be measured using an optical microscope, a scanning electron microscope, etc. Even if not described in the present disclosure, other methods and / or tools understood by those of ordinary skill in the art can be used to measure.

[0071] The thickness L2 of each of the first lead-out portion 121b and the second lead-out portion 122b along the z-axis direction may be: in the xz cross section passing through the center point of the y-axis direction of the multilayer capacitor 100, the length of any line segment connected from a point on the lower surface of each of the first lead-out portion 121b and the second lead-out portion 122b to its upper surface, the maximum value of the lengths of multiple line segments connected from a point on the lower surface of each of the first lead-out portion 121b and the second lead-out portion 122b to its upper surface, or the arithmetic mean of the lengths of the multiple line segments. The above-mentioned multiple line segments may be 5 or more line segments arranged at equal intervals. The thickness L2 of each of the first lead-out portion 121b and the second lead-out portion 122b along the z-axis direction may be measured using an optical microscope, a scanning electron microscope, etc. Even if not described in the present disclosure, other methods and / or tools understood by a person of ordinary skill in the art may be used for measurement.

[0072] The first lead-out portion 121b may include a first protrusion 121b1 at one end thereof. A ratio of a length L3 of the first protrusion 121b1 along the x-axis direction to a thickness L1 of the first capacitor portion 121a along the z-axis direction may be in a range of greater than or equal to 0.07 and less than 0.1. In addition, the second lead-out portion 122b may include a second protrusion 122b1 at one end thereof. A ratio of a length L3 of the second protrusion 122b1 along the x-axis direction to a thickness L1 of the second capacitor portion 122a along the z-axis direction may be in a range of greater than or equal to 0.07 and less than 0.1.

[0073] As an example, the ratio of the length L3 of the first protrusion 121b1 along the x-axis direction to the thickness L1 of the first capacitor portion 121a along the z-axis direction may be in a range of greater than or equal to 0.07 and less than or equal to 0.09. In addition, the ratio of the length L3 of the second protrusion 122b1 along the x-axis direction to the thickness L1 of the second capacitor portion 122a along the z-axis direction may be in a range of greater than or equal to 0.07 and less than or equal to 0.09.

[0074] The length L3 of each of the first protrusion 121b1 and the second protrusion 122b1 in the x-axis direction may be: in the xz cross section passing through the center point of the y-axis direction of the multilayer capacitor 100, the maximum value, minimum value or arithmetic mean value of the lengths of multiple line segments connected from one end of each of the first protrusion 121b1 and the second protrusion 122b1 in the x-axis direction to the other end thereof aligned with the third surface or the fourth surface of the body 110. The above-mentioned multiple line segments may be 5 or more line segments arranged at equal intervals. The length L3 of each of the first protrusion 121b1 and the second protrusion 122b1 in the x-axis direction may be measured using an optical microscope, a scanning electron microscope, etc. Even if not described in the present disclosure, other methods and / or tools understood by a person of ordinary skill in the art may be used.

[0075] (Table 1)

[0076] Referring to Table 1, if the ratio of the length L3 of the first protrusion 121b1 along the x-axis direction to the thickness L1 of the first capacitor portion 121a along the z-axis direction or the ratio of the length L3 of the second protrusion 122b1 along the x-axis direction to the thickness L1 of the second capacitor portion 122a along the z-axis direction is less than 0.07, radiation cracks are likely to occur. If the ratio of the length L3 of the first protrusion 121b1 along the x-axis direction to the thickness L1 of the first capacitor portion 121a along the z-axis direction or the ratio of the length L3 of the second protrusion 122b1 along the x-axis direction to the thickness L1 of the second capacitor portion 122a along the z-axis direction is greater than or equal to 0.1, electrode detachment is likely to occur. If the ratio of the length L3 of the first protrusion 121b1 along the x-axis direction to the thickness L1 of the first capacitor portion 121a along the z-axis direction or the ratio of the length L3 of the second protrusion 122b1 along the x-axis direction to the thickness L1 of the second capacitor portion 122a along the z-axis direction is greater than or equal to 0.07 and less than 0.1, the risk of radiation cracks can be reduced.

[0077] For example, the thickness of at least one of the first and second internal electrodes 121 and 122 along the z-axis direction may be 360 ​​nm to 440 nm or 360 nm to 400 nm. Here, the length L3 of at least one of the first and second protrusions 121 b 1 and 122 b 1 along the x-axis direction may be in the range of 28 nm to 40 nm, for example, in the range of 30 nm to 40 nm.

[0078] The first lead-out portion 121b and the second lead-out portion 122b may include a portion whose thickness increases in the z-axis direction toward the outside of the main body 110 along the x-axis direction. Specifically, the first lead-out portion 121b and the second lead-out portion 122b may include a portion whose thickness in the z-axis direction gradually increases in the x-axis direction toward the outside of the main body 110. In other words, the ratio of the amount of change in the z-axis direction of the first lead-out portion 121b and the second lead-out portion 122b to the amount of change in the x-axis direction may be constant. The first lead-out portion 121b and the second lead-out portion 122b may have a straight line shape with a constant slope. In addition, the first lead-out portion 121b and the second lead-out portion 122b may include a portion whose thickness in the z-axis direction increases in two vertical directions in the z-axis direction (i.e., two opposite directions in the z-axis direction) toward the outside of the main body 110 along the x-axis direction.

[0079] The ratio of the maximum thickness of the first lead portion 121b along the z-axis direction to the thickness L1 of the first capacitor portion 121a along the z-axis direction may be greater than 1.2 and less than 2.0. In addition, the ratio of the maximum thickness of the second lead portion 122b along the z-axis direction to the thickness L1 of the second capacitor portion 122a along the z-axis direction may be greater than 1.2 and less than 2.0.

[0080] As an example, the ratio of the maximum thickness of the first lead portion 121b along the z-axis direction to the thickness L1 of the first capacitor portion 121a along the z-axis direction may be greater than or equal to 1.3 and less than or equal to 1.9. In addition, the ratio of the maximum thickness of the second lead portion 122b along the z-axis direction to the thickness L1 of the second capacitor portion 122a along the z-axis direction may be greater than or equal to 1.3 and less than or equal to 1.9.

[0081] If the ratio of the maximum thickness of the first lead portion 121b along the z-axis direction to the thickness L1 of the first capacitor portion 121a along the z-axis direction or the ratio of the maximum thickness of the second lead portion 122b along the z-axis direction to the thickness L1 of the second capacitor portion 122a along the z-axis direction is less than or equal to 1.2, the effect of improving high temperature reliability may be small. If the ratio of the maximum thickness of the first lead portion 121b along the z-axis direction to the thickness L1 of the first capacitor portion 121a along the z-axis direction or the ratio of the maximum thickness of the second lead portion 122b along the z-axis direction to the thickness L1 of the second capacitor portion 122a along the z-axis direction is greater than or equal to 2.0, a short circuit may occur due to contact between adjacent internal electrodes in the vertical direction (z-axis direction).

[0082] If the ratio of the maximum thickness of the first lead portion 121b along the z-axis direction to the thickness L1 of the first capacitor portion 121a along the z-axis direction or the ratio of the maximum thickness of the second lead portion 122b along the z-axis direction to the thickness L1 of the second capacitor portion 122a along the z-axis direction is greater than 1.2 and less than 2.0, the high temperature reliability can be improved by increasing the thickness of the dielectric layer at the two end edges of the main body along the x-axis direction where the first lead portion 121b and the second lead portion 122b are provided.

[0083] The first protrusion 121 b 1 may be covered by the first external electrode 130 . The second protrusion 122 b 1 may be covered by the second external electrode 140 .

[0084] Hereinafter, characteristics and reliability measurement results of the multilayer capacitor 100 according to the embodiment are described with reference to Table 2. In the multilayer capacitor of the embodiment, the ratio of the maximum thickness of the lead portion in the z-axis direction to the thickness of the capacitance portion in the z-axis direction may be 1.6.

[0085] In the following, the protrusion of the comparative example multilayer capacitor may include a portion whose thickness decreases in the z-axis direction toward the outside of the body in the x-axis direction. In addition, the inner electrode of the comparative example stacked capacitor may not include a portion protruding from one surface of the body.

[0086] (Table 2)

[0087] In Table 2, "570L" means that the capacitor includes 570 layers, and "400L" means that the capacitor includes 400 layers. In Table 2, "MTTF" means mean time to failure, and "DF" means dissipation factor.

[0088] Referring to Table 2, it can be seen that the breakdown voltage (BDV) of the multilayer capacitor 100 of the embodiment is improved by about 33% and the high temperature reliability (mean time to failure (MTTF)) is improved by about 23% or about 52% compared with the comparative example, wherein the high temperature reliability test is performed at 125°C and 1.5Vr (Vr is the rated voltage).

[0089] Hereinafter, the measurement results of the step difference between adjacent internal electrodes of the two end edges (with the first lead portion 121b and the second lead portion 122b) of the main body 110 of the multilayer capacitor 100 according to the embodiment along the x-axis direction will be described with reference to Table 3. The inclination angle may refer to the angle at which the lead portions 121b and 122b are inclined relative to a line parallel to the x-axis. The step difference between adjacent lead portions 121b and 122b of the two end edges of the main body 110 in the x-axis direction and the inclination angle of the lead portions 121b and 122b may be measured by observing a cross section of the multilayer capacitor using an optical microscope, a scanning electron microscope, or the like.

[0090] (Table 3)

[0091] Referring to Table 3, it can be seen that the multilayer capacitor 100 of the embodiment has a smaller step difference and a smaller tilt angle than the multilayer capacitor of the comparative example. Therefore, the problems of BDV degradation and highly accelerated life test (HALT) caused by cumulative stacking at both end edges in the x-axis direction of the body 110 can be improved, and the electrode connectivity between the inner electrode and the outer electrode can be improved.

[0092] Hereinafter, the evaluation results of the radiation cracks of the multilayer capacitor 100 according to the embodiment will be described with reference to Table 4. The external electrodes of the multilayer capacitors of the comparative example and the embodiment may be formed by applying Cu and performing firing.

[0093] Radiative cracks may be cracks caused by the force of the outer electrode pressing into the body.

[0094] (Table 4)

[0095] Table 4 shows the results of two experiments conducted using the same experimental method to confirm reproducibility. Electrode firing was performed at 730°C for 70 minutes. Wherein, X represents a sample that did not generate radiation cracks.

[0096] Referring to Table 4, it can be seen that the occurrence of radiation cracks in the multilayer capacitor 100 of the embodiment is reduced compared to the comparative example.

[0097] In the following, reference will be made to Figure 5A first lead-out portion 121 b and a second lead-out portion 122 b of a multilayer capacitor according to a modified example are described. Figure 5 is shown along Figure 1 A cross-sectional view of a multilayer capacitor according to a modified example taken along line II-II' in FIG.

[0098] Unlike the multilayer capacitor according to the above-described embodiment, in the multilayer capacitor according to the modified example, the first lead portion 121b and the second lead portion 122b may include a portion having a constant thickness along the z-axis direction. In addition, for example, the first protrusion 121b1 and the second protrusion 122b1 may include a portion having a constant thickness along the z-axis direction. The portion having a constant thickness is a portion in which the thickness changes by, for example, 1% or less compared to the maximum thickness and the minimum thickness of the portion.

[0099] In the following, reference will be made to Figure 6 A first lead portion 121 b and a second lead portion 122 b of a multilayer capacitor according to another modified example are described. Figure 6 is shown along Figure 1 0 is a cross-sectional view of a multilayer capacitor according to another modified example taken along line II-II' in FIG.

[0100] Unlike the multilayer capacitor according to the above-described embodiment, in a multilayer capacitor according to another modified example, the first lead portion 121b and the second lead portion 122b may include a portion whose thickness along the z-axis direction increases in one direction along the z-axis direction toward the outside of the body 110 along the x-axis direction. For example, the first lead portion 121b and the second lead portion 122b may include a portion whose thickness along the z-axis direction increases in an upward direction along the z-axis direction toward the outside of the body 110 along the x-axis direction. However, the present disclosure is not limited thereto, and as another example, the first lead portion 121b and the second lead portion 122b may include a portion whose thickness along the z-axis direction increases in a downward direction along the z-axis direction toward the outside of the body 110 along the x-axis direction.

[0101] In the following, reference will be made to Figure 7 A first lead portion 121 b and a second lead portion 122 b of a multilayer capacitor according to another modified example are described. Figure 7 is shown along Figure 1 0 is a cross-sectional view of a multilayer capacitor according to another modified example taken along line II-II' in FIG.

[0102] Unlike the multilayer capacitor according to the above-described embodiment, in a multilayer capacitor according to another modified example, the first lead portion 121b and the second lead portion 122b may not include the first protrusion 121b1 and the second protrusion 122b1. In other words, the first lead portion 121b may be exposed through the third surface S3 of the body 110, but may not protrude from the third surface S3. In addition, the second lead portion 122b may be exposed through the fourth surface S4 of the body 110, but may not protrude from the fourth surface S4.

[0103] According to the multilayer capacitor of the above-mentioned embodiment and the modified example, the reliability can be improved by improving the thickness of the inner electrode, the connectivity between the inner electrode and the outer electrode can be improved by preventing the lead portion of the inner electrode from bending, and the delamination can be prevented. In addition, by forming the inner electrode to protrude from the body, the contact between the inner electrode and the outer electrode can be improved, and the risk of radiation cracks can be reduced by controlling the length of the protrusion.

[0104] While the present disclosure has been described in connection with what are presently considered to be practical embodiments, it should be understood that the present disclosure is not limited to the disclosed embodiments, but on the contrary is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A multilayer capacitor comprising: a main body including a dielectric layer and a plurality of inner electrodes stacked in a first direction, the plurality of inner electrodes being arranged to face each other with the dielectric layer interposed between the plurality of inner electrodes; as well as an outer electrode disposed on the body and connected to the inner electrode, Wherein, at least one of the plurality of inner electrodes comprises: a capacitor portion disposed to overlap the adjacent inner electrode; and a lead portion extending from the capacitor portion to be connected to the external electrode, including a protrusion protruding from one surface of the body in a second direction perpendicular to the first direction, and including a portion having a thickness along the first direction greater than a thickness of the capacitor portion along the first direction, and Wherein, a ratio of a length of the protrusion along the second direction to a thickness of the capacitor portion is within a range of greater than or equal to 0.07 and less than 0.

1.

2. The multilayer capacitor according to claim 1, wherein The lead-out portion includes a portion whose thickness increases in the first direction toward the outside of the body in the second direction.

3. The multilayer capacitor according to claim 2, wherein The thickness of the portion of the lead-out portion where the thickness increases in the first direction gradually increases toward the outside of the body in the second direction.

4. The multilayer capacitor according to claim 2, wherein The lead-out portion further includes a portion having a constant thickness along the first direction.

5. The multilayer capacitor according to claim 4, wherein The protrusion includes a portion having a constant thickness along the first direction.

6. The multilayer capacitor according to claim 1 or 2, wherein: The lead-out portion includes a portion whose thickness in the first direction increases in two opposite directions in the first direction toward the outside of the body in the second direction.

7. The multilayer capacitor according to claim 1 or 2, wherein: The lead-out portion includes a portion whose thickness in the first direction increases in one direction in the first direction toward the outside of the body in the second direction.

8. The multilayer capacitor according to claim 1 or 2, wherein: A ratio of a maximum thickness of the lead portion along the first direction to an average thickness of the capacitor portion along the first direction is within a range of greater than 1.2 and less than 2.

0.

9. The multilayer capacitor according to claim 1, wherein The protrusion is covered by the external electrode.

10. The multilayer capacitor according to claim 1, wherein The body includes a first surface and a second surface opposite to each other in the first direction, a third surface and a fourth surface opposite to each other in the second direction, and a fifth surface and a sixth surface opposite to each other in a third direction perpendicular to the first direction and the second direction, the external electrode includes a first external electrode and a second external electrode, the plurality of internal electrodes include first internal electrodes and second internal electrodes alternately arranged, the dielectric layer is interposed between the first internal electrode and the second internal electrode, the first internal electrode includes a first capacitor portion and a first lead-out portion, the first lead-out portion extends from the first capacitor portion to be connected to the first external electrode and includes a first protrusion protruding from the third surface of the body, and the second internal electrode includes a second capacitor portion and a second lead-out portion, the second capacitor portion overlaps the first capacitor portion in the first direction, the second lead-out portion extends from the second capacitor portion to be connected to the second external electrode and includes a second protrusion protruding from the fourth surface of the body.

11. The multilayer capacitor according to claim 10, wherein The first protrusion is covered by the first external electrode, and the second protrusion is covered by the second external electrode.

12. The multilayer capacitor according to claim 1 or 2, wherein: The outer electrode comprises: a conductive layer disposed on a surface of the body and connected to the plurality of internal electrodes; and The plating layer is arranged on the conductive layer.

13. The multilayer capacitor according to claim 1, wherein A thickness of the protrusion along the first direction is greater than a thickness of the capacitor along the first direction.

14. The multilayer capacitor according to claim 1, wherein The protrusion is a thickest portion of the at least one inner electrode among the plurality of inner electrodes.

15. The multilayer capacitor according to claim 1, wherein The length of the protrusion is in the range of 28 nm to 40 nm.

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