Multilayer capacitor

Abstract

The present disclosure provides a multilayer capacitor. The multilayer capacitor according to the present disclosure includes: a capacitor body including a dielectric layer and an inner electrode; and an outer electrode disposed on an outer side of the capacitor body, and the inner electrode includes a Ni-Ge alloy, and when an average content of Ge with respect to Ni at a central portion of the inner electrode based on a weight percentage is represented by X, X represents an average content of Ge with respect to Ni at a central portion of the inner electrode, and X represents an average content of Ge with respect to Ni at a central portion of the inner electrode. And when the average content of Ge with respect to Ni based on weight percentage at a point spaced 20 nm from an interface between the inner electrode and the dielectric layer toward the central portion of the inner electrode is represented by Y, the relationship between X and Y satisfies expression 1: # imgabs0 #

Description

Technical Field

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

[0002] Recently, as the multifunctionalization and miniaturization of electronic devices have rapidly developed, the miniaturization and performance improvement of electronic components are also progressing rapidly. In addition, the demand for high reliability of electrical devices used in automobiles, network equipment, etc. and electronic components used in industry is also increasing significantly.

[0003] In order to meet such market demands, competition for technical development of passive components such as inductors, capacitors or resistors has been accelerating. In particular, a lot of efforts are needed to occupy the market by developing various multilayer ceramic capacitor (MLCC) products, whose applications and uses as passive components have been increasing.

[0004] In addition, MLCC is a capacitor made by stacking dielectric layers and internal electrodes, and is used in various electronic devices such as mobile phones, laptop computers, and liquid crystal televisions (LCD TVs).

[0005] With recent technological advances, MLCCs have been required to be miniaturized and have higher capacitance, which requires reducing the thickness of the internal electrodes and dielectric layers. As the thickness of the dielectric layer decreases, the field strength applied to each layer becomes relatively stronger. Therefore, there is a problem that the reliability of the capacitor decreases and the capacitance also decreases due to the deterioration of the internal electrode connectivity. Summary of the invention

[0006] The present disclosure provides a multilayer capacitor having improved reliability and high capacitance by improving smoothness and connectivity of internal electrodes.

[0007] However, the effects of the present disclosure are not limited to the above-mentioned purposes, and they can be variously extended without departing from the technical spirit and scope of the present disclosure.

[0008] A multilayer capacitor according to the present disclosure includes: a capacitor body including a dielectric layer and an inner electrode; and an outer electrode provided on an outer side of the capacitor body, and the inner electrode includes a Ni-Ge alloy, and when an average content of Ge relative to Ni based on weight percentage at a central portion of the inner electrode is represented by X, and an average content of Ge relative to Ni based on weight percentage at a point spaced 20 nm from an interface between the inner electrode and the dielectric layer toward the central portion of the inner electrode is represented by Y, a relationship between X and Y satisfies Expression 1:

[0009] [Expression 1]

[0010]

[0011] The average content of Ge relative to Ni in the inner electrode can be in the range from 0.1 wt% to 10 wt%.

[0012] The value of X can be in the range from 0.90 wt% to 1.80 wt%.

[0013] The value of Y can be in the range from 1.00 wt% to 1.50 wt%.

[0014] The average thickness of the inner electrode can be in the range from 0.05 μm to 1 μm.

[0015] The average thickness of the dielectric layer can be in the range from 0.05 μm to 2.5 μm.

[0016] The dielectric layer may include a dielectric, and the dielectric includes a main component and a sub-component.

[0017] The main component may include: Ba m TiO3, where 0.995 ≤ m ≤ 1.10, (Ba 1-x Ca x ) m (Ti 1-y Zr y )O3, where 0.995 ≤ m ≤ 1.10, 0 ≤ x ≤ 0.10 and 0 < y ≤ 0.20,

[0018] Ba m (Ti 1-x Zr x )O3, where 0.995 ≤ m ≤ 1.10 and 0 < x ≤ 0.10, (Ba 1-x Ca x ) m (Ti 1-y Sn y )O3, where 0.995 ≤ m ≤ 1.10, 0 ≤ x ≤ 0.10 and 0 < y ≤ 0.20, or a combination thereof.

[0019] The sub-component may include dysprosium (Dy), vanadium (V), manganese (Mn), chromium (Cr), silicon (Si), aluminum (Al), magnesium (Mg), tin (Sn), antimony (Sb), germanium (Ge), gallium (Ga), indium (In), barium (Ba), lanthanum (La), yttrium (Y), actinium (Ac), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), hafnium (Hf) or a combination thereof.

[0020] According to another aspect of the present disclosure, a multilayer capacitor includes: a capacitor body including a dielectric layer and internal electrodes; and external electrodes provided on an outer side of the capacitor body, wherein the internal electrodes include a Ni—Ge alloy, and an average content of Ge relative to Ni in the internal electrodes does not exceed 10 wt%, and when an average content of Ge relative to Ni by weight percentage at a central portion of the internal electrodes is represented by X, and an average content of Ge relative to Ni by weight percentage at a point spaced 20 nm from an interface between the internal electrodes and the dielectric layer toward the central portion of the internal electrodes is represented by Y, a relationship between X and Y satisfies Expression 1:

[0021] [Expression 1]

[0022]

[0023] The value of X may be in a range from 0.90 wt% to 1.80 wt%.

[0024] The value of Y may be in a range from 1.00 wt% to 1.50 wt%.

[0025] An average thickness of the internal electrodes may be in a range from 0.05 μm to 1 μm.

[0026] An average thickness of the dielectric layer may be in a range from 0.05 μm to 2.5 μm.

[0027] The dielectric layer may include a dielectric including a main component and a sub-component.

[0028] The main component may include: Ba m TiO3, where 0.995 ≤ m ≤ 1.10, (Ba 1-x Ca x ) m (Ti 1-y Zr y )O3, where 0.995 ≤ m ≤ 1.10, 0 ≤ x ≤ 0.10 and 0 < y ≤ 0.20, Ba m (Ti 1-x Zr x )O3, where 0.995 ≤ m ≤ 1.10 and 0 < x ≤ 0.10, (Ba 1-x Ca x ) m (Ti 1-y Sn y )O3, where 0.995 ≤ m ≤ 1.10, 0 ≤ x ≤ 0.10 and 0 < y ≤ 0.20, or a combination thereof.

[0029] The secondary components may include dysprosium (Dy), vanadium (V), manganese (Mn), chromium (Cr), silicon (Si), aluminum (Al), magnesium (Mg), tin (Sn), antimony (Sb), germanium (Ge), gallium (Ga), indium (In), barium (Ba), lanthanum (La), yttrium (Y), actinium (Ac), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), hafnium (Hf), or a combination thereof.

[0030] According to the present disclosure, a multilayer capacitor having improved reliability and high capacitance by improving smoothness and connectivity of internal electrodes may be provided.

[0031] However, various advantages and various advantageous effects of the present disclosure are not limited to the above-mentioned advantages and advantageous effects and can be more easily understood in the course of describing specific embodiments of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a perspective view showing a multilayer capacitor according to an embodiment.

[0033] Figure 2 is along Figure 1 A cross-sectional view of the multilayer capacitor taken along line II'.

[0034] Figure 3 It is shown Figure 1 An exploded perspective view of the stacked structure in the capacitor body.

[0035] Figure 4 is a transmission electron microscope (TEM) image showing a result of component analysis of an internal electrode included in the multilayer capacitor according to the embodiment.

[0036] Figure 5 An energy dispersive spectroscopy (EDS) profile of Ni is shown.

[0037] Figure 6 The EDS profile of Ge is shown. DETAILED DESCRIPTION

[0038] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement them. The drawings and descriptions are considered to be illustrative rather than restrictive in nature. Throughout the specification, the same reference numerals represent the same elements. In addition, the drawings are provided to help easily understand the embodiments disclosed in this specification, and the technical spirit disclosed in this specification is not limited by the drawings. It will be understood that the present disclosure includes all modifications, equivalents, and alternatives included in the spirit and technical scope of the present disclosure.

[0039] Terms including ordinal numbers such as "first" and "second" are used to describe various constituent elements, but the constituent elements are not limited by the terms. The terms are used only to distinguish one constituent element from another constituent element.

[0040] When a component is referred to as being "connected" or "coupled" to another component, it will be understood that the component may be directly connected or directly coupled to the other component, or other intervening components may exist. In contrast, when a component is referred to as being "directly connected" or "directly coupled" to another component, it will be understood that there are no other intervening components.

[0041] In the present application, it will be understood that the terms "include" and "have" are intended to indicate the presence of the features, numbers, steps, operations, components, or combinations thereof described in the specification, and do not exclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, or combinations thereof. Therefore, unless explicitly described to the contrary, the word "include" and variations such as "comprises" or "have" will be understood to imply the inclusion of the stated elements but not the exclusion of any other elements.

[0042] Figure 1 is a perspective view showing a multilayer capacitor 100 according to an embodiment, Figure 2 is along Figure 1 A cross-sectional view of the multilayer capacitor 100 taken along line II' in FIG. Figure 3 It is shown Figure 1 An exploded perspective view of the stacked structure in the capacitor body 110.

[0043] In order to clearly describe the present embodiment, the directions are defined as follows: the L-axis direction, the W-axis direction, and the T-axis direction shown in the drawings represent the length direction, the width direction, and the thickness direction of the capacitor body 110, respectively. Here, the thickness direction (T-axis direction) may be a direction perpendicular to the wide surface (main surface) of the sheet-like constituent element, and may be used as, for example, the same concept as the stacking direction along which the dielectric layer 111 is stacked. The length direction (L-axis direction) may be a direction extending in parallel with the wide surface (main surface) of the sheet-like constituent element, and may be a direction perpendicular to the thickness direction (T-axis direction), and may be, for example, a direction along which the first external electrode 131 and the second external electrode 132 are opposite to each other. The width direction (W-axis direction) may be a direction extending in parallel with the wide surface (main surface) of the sheet-like constituent element, and may be a direction perpendicular to the thickness direction (T-axis direction) and the length direction (L-axis direction), and the length of the sheet-like constituent element in the length direction (L-axis direction) may be longer than the length of the sheet-like constituent element in the width direction (W-axis direction).

[0044] Reference Figures 1 to 3 , the multilayer capacitor 100 according to the embodiment may include a capacitor body 110 and first and second external electrodes 131 and 132 provided on both ends of the capacitor body 110 opposite to each other in a length direction (L-axis direction).

[0045] The capacitor body 110 may have, for example, a substantially hexahedral shape.

[0046] In the present embodiment, for convenience of explanation, in the capacitor body 110, two surfaces opposite to each other in the thickness direction (T-axis direction) are defined as the first surface and the second surface, two surfaces connected to the first surface and the second surface and opposite to each other in the length direction (L-axis direction) are defined as the third surface and the fourth surface, and two surfaces connected to the first surface and the second surface, connected to the third surface and the fourth surface and opposite to each other in the width direction (W-axis direction) are defined as the fifth surface and the sixth surface. Here, the third surface may be a surface from which one end of the first internal electrode 121 is exposed, and the fourth surface may be a surface from which one end of the second internal electrode 122 is exposed.

[0047] As an example, the first surface as the lower surface may be a mounting surface. In addition, the first to sixth surfaces may be flat, however, the present embodiment is not limited thereto, for example, the first to sixth surfaces may be curved surfaces having a convex central portion, and the boundaries (i.e., edges) of the respective surfaces may be rounded.

[0048] The shape and size of the capacitor body 110 and the number of stacked dielectric layers 111 are not limited to those shown in the drawings of the present embodiment.

[0049] The capacitor body 110 is formed by stacking a plurality of dielectric layers 111 in a thickness direction (T-axis direction) and sintering the plurality of dielectric layers 111, and the capacitor body 110 includes a plurality of dielectric layers 111 and a first internal electrode 121 and a second internal electrode 122 alternately arranged in the thickness direction (T-axis direction), and the dielectric layer 111 is between the first internal electrode 121 and the second internal electrode 122.

[0050] In this case, adjacent dielectric layers 111 in the capacitor body 110 may be integrated so that it is difficult to identify a boundary between the adjacent dielectric layers 111 without using a scanning electron microscope (SEM).

[0051] Furthermore, capacitor body 110 may include footprints 112 and 113 and an active area.

[0052] The active region is a portion that contributes to forming the capacitance of the multilayer capacitor 100. As an example, the active region may be a region where the first and second internal electrodes 121 and 122 stacked in the thickness direction (T-axis direction) overlap each other.

[0053] Covering regions 112 and 113 are edge portions in the thickness direction and may be located on the upper and lower surfaces of the active region in the thickness direction (T-axis direction), respectively. Covering regions 112 and 113 may be stacked on the upper and lower surfaces of the active region, respectively, and each of covering regions 112 and 113 may include a single dielectric layer or include two or more dielectric layers.

[0054] In addition, the capacitor body 110 may further include a side covering area. The side covering area is an edge portion in the width direction, and may be located on two side surfaces of the effective area that are opposite to each other in the width direction (W-axis direction) (the two side surfaces are respectively close to the fifth surface and the sixth surface of the capacitor body 110). The side covering area may be formed by stacking dielectric green sheets having a conductive paste layer for forming an internal electrode and sintering them. When the conductive paste layer is formed on the surface of the dielectric green sheet, the conductive paste may be applied only on a portion of the surface of the dielectric green sheet and the conductive paste may not be applied on the area of ​​the surface of the dielectric green sheet where the side covering area is to be formed.

[0055] The cover regions 112 and 113 and the side cover regions serve to prevent damage to the first and second internal electrodes 121 and 122 due to physical stress or chemical stress.

[0056] The multilayer capacitor 100 according to the embodiment includes a capacitor body 110 including a dielectric layer 111 and internal electrodes 121 and 122 , and external electrodes 131 and 132 disposed at the outside of the capacitor body 110 , and the internal electrodes 121 and 122 include a Ni—Ge alloy.

[0057] Germanium (Ge) is an element whose oxidation tendency is very similar to that of tin (Sn). When forming the inner electrode, if Ge is added to the inner electrode and sintered together with Ni in a reducing atmosphere, a Ni-Ge alloy is uniformly formed throughout the inner electrode.

[0058] The Ni-Ge alloy can reduce the grain boundary energy and surface tension of Ni, thereby improving the smoothness and connectivity of the internal electrodes. If the smoothness of the internal electrodes 121 and 122 is improved, the electric field strength applied to each dielectric layer can be dispersed even if the thickness of the dielectric layer 111 is reduced.

[0059] In addition, by alloying Ge, which is a metalloid, with Ni, the insulation of the interface between the dielectric layer 111 and the internal electrodes 121 and 122 can be improved, so that the reliability can be improved. In addition, since the sintering rate of Ni is delayed during the process of alloying Ni with Ge, the internal electrode connectivity is further improved. Therefore, a capacitor with higher capacitance can be realized.

[0060] The internal electrodes 121 and 122 including the Ni-Ge alloy may be formed by adding Ge or GeO2 nanoparticles to a conductive paste for forming the internal electrodes, controlling the oxygen partial pressure to 10 -9 Up to 10 -10 (MPa), and sintering is performed for 10 to 20 minutes.

[0061] The internal electrodes 121 and 122 may further include a conductive metal other than the above-mentioned Ni-Ge alloy. The conductive metal other than the above-mentioned Ni-Ge alloy may include at least one of Ni, Cu, Ag, Pd, Au, and alloys thereof.

[0062] In an embodiment, the average content of Ge relative to Ni in the internal electrodes 121 and 122 based on weight percentage may be in the range from 0.1wt% to 10wt%, that is, the average content of Ge relative to Ni in the internal electrodes 121 and 122 based on weight percentage does not exceed 10wt%, for example, in the range from 0.5wt% to 10wt%, in the range from 0.5wt% to 8wt%, or in the range from 1wt% to 8wt%.

[0063] When the average content (wt %) of Ge relative to Ni in the internal electrodes 121 and 122 is less than 0.1 wt %, it may be difficult to improve the reliability of the capacitor and to achieve high capacitance.

[0064] When the average content (wt %) of Ge relative to Ni in the internal electrodes 121 and 122 exceeds 10 wt %, the melting point of the Ni—Ge alloy may become too low, and thus the smoothness and connectivity of the internal electrodes 121 and 122 may be deteriorated.

[0065] According to the multilayer capacitor 100 of the embodiment, when the average content (wt %) of Ge relative to Ni at the central portion of the internal electrodes 121 and 122 is represented by X, and the average content (wt %) of Ge relative to Ni at a point spaced 20 nm from the interface between the internal electrodes 121 and 122 and the dielectric layer 111 toward the central portion of the internal electrodes 121 and 122 is represented by Y, the relationship between X and Y satisfies the following Expression 1.

[0066] [Expression 1]

[0067]

[0068] When the expression 1 above When it exceeds 0.2, the alloy of Ge and Ni may not be uniformly formed in the internal electrodes 121 and 122 , and thus it may be difficult to improve the smoothness and connectivity of the internal electrodes 121 and 122 .

[0069] The central portion of the internal electrodes 121 and 122 may refer to a midpoint between a point on one surface of any one of the internal electrodes and a point on the other surface of any one of the internal electrodes located at the shortest distance from the above point in a cross section taken along the L-axis direction and the T-axis direction at the center of the capacitor body 110 in the W-axis direction. In addition, the central portion of the internal electrodes 121 and 122 may refer not only to the midpoint but also to an area within ±30% offset from the midpoint in the T-axis direction.

[0070] When the average content (wt %) of Ge relative to Ni at the central portion of the internal electrodes 121 and 122 is represented by X, the value of X may be in the range from 0.90 wt % to 1.80 wt %, for example, in the range from 0.95 wt % to 1.80 wt %, in the range from 0.95 wt % to 1.60 wt %, or in the range from 0.95 wt % to 1.55 wt %.

[0071] The surface portion of the internal electrodes 121 and 122 may be a region other than the central portion of the internal electrodes 121 and 122, and may refer to a point 20 nm away from an interface between the internal electrodes 121 and 122 and the dielectric layer 111 in the T-axis direction toward the central portion of the internal electrodes 121 and 122. In addition, the surface portion may refer not only to the above point but also to a region within ±30% offset from the above point in the T-axis direction.

[0072] When the average content (wt %) of Ge relative to Ni in the surface portion of the internal electrodes 121 and 122 is represented by Y, the value of Y may be in the range from 1.00 wt % to 1.50 wt %, for example, in the range from 1.10 wt % to 1.50 wt % or in the range from 1.10 wt % to 1.30 wt %.

[0073] Figure 4 is a TEM image showing a result of component analysis of the internal electrodes 121 and 122 included in the multilayer capacitor 100 according to the embodiment. Figure 5 The EDS surface distribution diagram of Ni is shown. Figure 5 In the figure, the green area indicates the presence of Ni. Figure 6 The EDS surface distribution diagram of Ge is shown. Figure 6 In the figure, the red area indicates the presence of Ge.

[0074] Reference Figures 4 to 6 As described above, the average content (wt %) of Ge relative to Ni in the inner electrodes 121 and 122 can be measured by transmission scanning microscopy (TEM)-energy dispersive X-ray spectroscopy (EDS) quantitative analysis. Even if not described in the present disclosure, other methods and / or tools understood by those of ordinary skill in the art may be used.

[0075] As an example, the average content (wt%) of Ge relative to Ni in the internal electrodes 121 and 122 may be obtained by selecting five or more arbitrary internal electrodes, selecting 10 arbitrary points in each internal electrode, quantitatively analyzing Ni and Ge at the selected 10 points of each internal electrode by transmission electron microscopy-energy dispersive spectrometer (TEM-EDS), and calculating the arithmetic mean of the measured values. That is, the average content (wt%) of Ge relative to Ni in the internal electrodes 121 and 122 may be confirmed by measuring the average content (wt%) of Ge relative to Ni in five or more arbitrary internal electrodes without measuring all the internal electrodes in the multilayer capacitor 100.

[0076] As an example, the average content (wt %) X of Ge relative to Ni at the central portion of the internal electrodes 121 and 122 can be obtained in the following manner: five or more arbitrary internal electrodes are selected, five points corresponding to the central portion of each internal electrode are selected at equal intervals in each internal electrode, Ni and Ge are quantitatively analyzed at the above-selected five points in each internal electrode by TEM-EDS, and the arithmetic mean of the measured values ​​is calculated.

[0077] As an example, the average content (wt %) Y of Ge relative to Ni in the surface portion of the internal electrodes 121 and 122 can be obtained in the following manner: five or more arbitrary internal electrodes are selected, five points corresponding to points about 20 nm away from the interface between the internal electrode and the dielectric layer toward the center portion of the internal electrode are selected at equal intervals in each internal electrode, Ni and Ge are quantitatively analyzed at the above-selected five points of each internal electrode by TEM-EDS, and the arithmetic mean of the measured values ​​is calculated.

[0078] The first inner electrode 121 and the second inner electrode 122 are electrodes having different polarities and may be alternately arranged along the T-axis direction so that the first inner electrodes 121 and the second inner electrodes 122 adjacent to each other are opposite to each other and the dielectric layer 111 is interposed between the first inner electrode 121 and the second inner electrode 122, and one end of the first inner electrode 121 may be exposed from the third surface of the capacitor body 110, and one end of the second inner electrode 122 may be exposed from the fourth surface of the capacitor body 110.

[0079] 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 .

[0080] Ends of the first and second internal electrodes 121 and 122 alternately exposed from the third and fourth surfaces of the capacitor body 110 may be electrically connected to the first and second external electrodes 131 and 132 , respectively.

[0081] In addition, the first and second internal electrodes 121 and 122 may include dielectric particles having the same composition as that of the ceramic material included in the dielectric layer 111 .

[0082] The first and second internal electrodes 121 and 122 may be formed using a conductive paste including a conductive metal. A printing method of the conductive paste may include a screen printing method, a gravure printing method, and the like.

[0083] As an example, the average thickness of the first internal electrode 121 and / or the second internal electrode 122 may be equal to or greater than 0.05 μm, 0.1 μm, 0.2 μm, or 0.25 μm, and may be equal to or less than 1 μm, 0.5 μm, 0.4 μm, or 0.3 μm. For example, the average thickness of the first internal electrode 121 and / or the second internal electrode 122 may be in the range from 0.05 μm to 1 μm.

[0084] The average thickness of the first internal electrode 121 and / or the second internal electrode 122 may be measured by the following method.

[0085] First, a cross-sectional sample is prepared in the following manner: the multilayer capacitor 100 is placed in an epoxy resin mixture and cured, the L-axis direction-T-axis direction side surface of the capacitor body 110 is polished to half of the W-axis direction, and it is fixed and maintained in a vacuum atmosphere chamber to obtain a cross-section of the capacitor body 110 along the L-axis direction and the T-axis direction taken at the center of the W-axis direction.

[0086] Next, a SEM image is obtained by observing the cross-sectional sample with a scanning electron microscope (SEM).

[0087] In the SEM image of the cross-sectional sample, the center point of the first internal electrode 121 or the second internal electrode 122 in the length direction (L-axis direction) is set as a reference point, and the arithmetic mean of the thickness of the first internal electrode 121 or the second internal electrode 122 at 10 points at a predetermined interval from the reference point is obtained. In this way, the average thickness of the first internal electrode 121 or the second internal electrode 122 may be obtained. Even if not described in the present disclosure, other methods and / or tools understood by those of ordinary skill in the art may be used.

[0088] The predetermined interval may be adjusted according to the scale of the SEM image, and may be, for example, 1 μm to 100 μm, 1 μm to 50 μm, or 1 μm to 10 μm.

[0089] In this case, all 10 points should be located within the first inner electrode 121 or the second inner electrode 122, and if all 10 points are not located within the first inner electrode 121 or the second inner electrode 122, the position of the reference point may be changed or the predetermined interval may be adjusted.

[0090] The dielectric layer 111 includes a dielectric, and the dielectric may include a main component and a sub component.

[0091] The main component is a base material of the dielectric, has a high dielectric constant, and contributes to the formation of the dielectric constant of the multilayer capacitor 100 .

[0092] As an example, the main component may be a dielectric material containing Ba m TiO3 (where 0.995≤m≤1.10), (Ba 1-x Ca x ) m (Ti 1-y Zr y )O3(where 0.995≤m≤1.10, 0≤x≤0.10 and 0 <y≤0.20)、Ba m (Ti 1- x Zr x)O3 (where 0.995 ≤ m ≤ 1.10 and 0 < x ≤ 0.10), (Ba 1-x Ca x ) m (Ti 1-y Sn y )O3 (where 0.995 ≤ m ≤ 1.10, 0 ≤ x ≤ 0.10 and 0 < y ≤ 0.20) or a combination thereof.

[0093] As an example, the main component may include BaTiO3, Ba(Ti,Zr)O3, Ba(Ti,Sn)O3, (Ba,Ca)TiO3, (Ba,Ca)(Ti,Zr)O3, (Ba,Ca)(Ti,Sn)O3, (Ba,Sr)TiO3, (Ba,Sr)(Ti,Zr)O3, (Ba,Sr)(Ti,Sn)O3 or a combination thereof.

[0094] As an example, the secondary component may include dysprosium (Dy), vanadium (V), manganese (Mn), chromium (Cr), silicon (Si), aluminum (Al), magnesium (Mg), tin (Sn), antimony (Sb), germanium (Ge), gallium (Ga), indium (In), barium (Ba), lanthanum (La), yttrium (Y), actinium (Ac), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), hafnium (Hf) or a combination thereof.

[0095] The dielectric layer 111 may further include at least one of a ceramic additive, an organic solvent, a binder, and a dispersant.

[0096] As an example, the average thickness of the dielectric layer 111 may be equal to or greater than 0.05 μm, 0.1 μm or 0.2 μm, and may be equal to or less than 2.5 μm, 1.5 μm, 0.5 μm or 0.4 μm. When the average thickness of the dielectric layer 111 is less than 0.05 μm, it may be difficult to verify the improvement in reliability. For example, the average thickness of the dielectric layer 111 may be in the range from 0.05 μm to 2.5 μm.

[0097] The average thickness of the dielectric layer 111 may be the arithmetic mean obtained by the following method: in the SEM image of the cross-sectional sample, the center point in the length direction (L-axis direction) of the dielectric layer 111 is set as the reference point, and the thicknesses of the dielectric layer 111 at 10 points at a predetermined interval from the reference point are averaged. Even if not described in the present disclosure, other methods and / or tools understood by those of ordinary skill in the art may be used.

[0098] The predetermined interval may be adjusted according to the scale of the SEM image, and may be, for example, 1 μm to 100 μm, 1 μm to 50 μm, or 1 μm to 10 μm.

[0099] In this case, all 10 points should be located within the dielectric layer 111, and if all 10 points are not located within the dielectric layer 111, the positions of the reference points may be changed or the above-mentioned predetermined intervals may be adjusted.

[0100] The first and second external electrodes 131 and 132 may receive voltages of different polarities and may be electrically connected to exposed portions of the first and second internal electrodes 121 and 122 , respectively.

[0101] According to the above configuration, when a predetermined voltage is applied between the first external electrode 131 and the second external electrode 132, charges are accumulated between the first internal electrode 121 and the second internal electrode 122 facing each other. At this time, the capacitance of the multilayer capacitor 100 is proportional to the overlapping area where the first internal electrode 121 and the second internal electrode 122 overlap each other in the T-axis direction in the active region.

[0102] The first outer electrode 131 may be disposed on the third surface of the capacitor body 110, may include a first connection portion connected to the first inner electrode 121, and may include a first band portion disposed at an edge where the third surface of the capacitor body 110 intersects with at least one of the first surface, the second surface, the fifth surface, and the sixth surface of the capacitor body 110. The second outer electrode 132 may be disposed on the fourth surface of the capacitor body 110, may include a second connection portion connected to the second inner electrode 122, and may include a second band portion disposed at an edge where the fourth surface of the capacitor body 110 intersects with at least one of the first surface, the second surface, the fifth surface, and the sixth surface of the capacitor body 110.

[0103] The first band portion may extend from the first connection portion to a portion of at least one of the first surface, the second surface, the fifth surface, and the sixth surface of the capacitor body 110, and the second band portion may extend from the second connection portion to a portion of at least one of the first surface, the second surface, the fifth surface, and the sixth surface of the capacitor body 110. The first band portion and the second band portion may be used to improve the bonding strength of the first and second external electrodes 131 and 132 to the capacitor body 110.

[0104] As an example, each of the first and second external electrodes 131 and 132 may include a sintered metal layer contacting the capacitor body 110 , a conductive resin layer disposed to cover the sintered metal layer, and a plated layer disposed to cover the conductive resin layer.

[0105] The sintered metal layer may contain conductive metal and glass.

[0106] As an example, the sintered metal layer may include a conductive metal such as copper (Cu), nickel (Ni), silver (Ag), palladium (Pd), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), lead (Pb) and at least one of their alloys. For example, the conductive metal includes copper (Cu) which may mean that the conductive metal includes a single substance of copper (Cu) or an alloy containing copper (Cu). When the conductive metal includes copper, other metals other than copper may be included in an amount of 5 mol or less based on 100 mol of copper.

[0107] As an example, the sintered metal layer may include a component containing an oxide, such as glass, and the sintered metal layer may include, for example, one or more selected from the group consisting of silicon oxide, boron oxide, aluminum oxide, transition metal oxide, alkali metal oxide, and alkaline earth metal oxide. The transition metal may be selected from the group consisting of zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), and nickel (Ni), the alkali metal may be selected from the group consisting of lithium (Li), sodium (Na), and potassium (K), and the alkaline earth metal may be selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).

[0108] Alternatively, the conductive resin layer may be formed on the sintered metal layer, and, for example, may be formed to completely cover the sintered metal layer. In addition, the first and second external electrodes 131 and 132 may not include the sintered metal layer, and in this case, the conductive resin layer may directly contact the capacitor body 110.

[0109] The conductive resin layer may extend to the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110, and the length of the region (i.e., the band portion) where the conductive resin layer extends to the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110 may be longer than the length of the region (i.e., the band portion) where the sintered metal layer extends to the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110. In other words, the conductive resin layer may be formed on the sintered metal layer, and may be formed to completely cover the sintered metal layer.

[0110] The conductive resin layer contains resin and conductive metal.

[0111] The resin contained in the conductive resin layer is not particularly limited as long as it has adhesiveness and impact absorption and can be mixed with the conductive metal powder to form a paste, and the resin may contain, for example, phenolic resin, acrylic resin, silicone resin, epoxy resin or polyimide resin.

[0112] The conductive metal contained in the conductive resin layer serves to electrically connect the conductive resin layer to the first and second internal electrodes 121 and 122 or the sintered metal layer.

[0113] The conductive metal contained in the conductive resin layer may have at least one of a spherical shape and a thin sheet shape. In other words, the conductive metal may be formed only in a thin sheet shape, or may be formed only in a spherical shape, or may be formed in a mixed form of a thin sheet shape and a spherical shape.

[0114] Here, the spherical shape may include a shape that is not a completely spherical shape, and may include, for example, a shape in which the ratio of the length of the major axis to the length of the minor axis ([length of the major axis] / [length of the minor axis]) is less than or equal to 1.45. The flake shape may refer to a flat and elongated shape, but is not particularly limited, and may be, for example, a shape in which the ratio of the length of the major axis to the length of the minor axis ([length of the major axis] / [length of the minor axis]) is greater than or equal to 1.95.

[0115] The first and second external electrodes 131 and 132 may further include a plating layer disposed on an outer side of the conductive resin layer.

[0116] The plating layer may include at least one of nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), lead (Pb) and alloys thereof. As an example, each plating layer may be a nickel (Ni) plating layer or a tin (Sn) plating layer, or may be a form in which a nickel (Ni) plating layer and a tin (Sn) plating layer are sequentially stacked, or may be a form in which a tin (Sn) plating layer, a nickel (Ni) plating layer and a tin (Sn) plating layer are sequentially stacked. Optionally, each plating layer may include a plurality of nickel (Ni) plating layers and / or a plurality of tin (Sn) plating layers.

[0117] The plating layer may improve the mounting characteristics of the multilayer capacitor 100 on a substrate as well as the structural reliability, durability against the outside, heat resistance, and equivalent series resistance (ESR) of the multilayer capacitor 100 .

[0118] Hereinafter, specific examples of the present disclosure will be presented. However, the following examples are only intended to specifically illustrate or describe the present disclosure and should not be interpreted as limiting the scope of the present disclosure.

[0119] Example

[0120] The multilayer capacitor was manufactured by adjusting the contents of Ni and Ge in the paste for the inner electrode and adjusting the oxygen partial pressure condition. During the manufacture of the multilayer capacitor, the oxygen partial pressure was controlled to be about 10 -9 to about 10 -10 (MPa) and sintering was performed for about 10 minutes. In the manufactured multilayer capacitor, the average thickness of the inner electrodes was 0.25 μm, and the average thickness of the dielectric layer was 1.0 μm.

[0121] Specifically, multilayer capacitors of Examples 1 to 7 and Comparative Examples 1 to 3 were manufactured, in which the average content (wt %) of Ge relative to Ni in the internal electrodes was as shown in Table 2 below.

[0122] Furthermore, multilayer capacitors of Examples 4-1 to 4-4 and Comparative Examples 4-1 and 4-2 were manufactured, wherein the average content (wt%) of Ge relative to Ni in the inner electrode was 3.5 wt %, and The values ​​of are shown in Table 3 below.

[0123] Table 1 below shows the average content (wt %) of Ge relative to Ni measured from the central portion and the surface portion of five arbitrary internal electrodes, that is, the average content (X) of Ge relative to Ni at the central portion of the internal electrode and the average content (Y) of Ge relative to Ni in the surface portion of the internal electrode.

[0124] (Table 1)

[0125]

[0126] Evaluation example

[0127] Evaluation Example 1: MTTF (Mean Time to Failure) Measurement

[0128] The MTTF (Mean Time to Failure) value was measured by performing a high temperature load test on 400 samples of each of the Examples and Comparative Examples under the conditions of 125° C. and 8V.

[0129] At this time, the time when the insulation resistance becomes 10 kΩ or less is set as a fixed time, and in Tables 2 and 3, using the MTTF value of Comparative Example 1 as Reference Value 1, relative values ​​of the example and the comparative example are calculated.

[0130] Evaluation Example 2: Capacitor

[0131] The capacitance was measured with an LCR meter (inductance capacitance resistance meter) under the conditions of 1 kHz and AC 0.5 V, and in Table 2, using the capacitance of Comparative Example 1 as Reference Value 1, relative values ​​of the example and the comparative example were calculated.

[0132] (Table 2)

[0133]

[0134]

[0135] Referring to Table 2, Comparative Example 1 does not include the Ni—Ge alloy containing Ge in the internal electrode, and Comparative Examples 2 and 3 correspond to the case where an excessive amount of Ge is included in the internal electrode.

[0136] Referring to Table 2, it can be seen that the multilayer capacitors of Examples 1 to 7 have higher capacitance and higher MTTF values, and are therefore more reliable, compared to Comparative Examples 1 to 3. That is, when the average content (wt%) of Ge relative to Ni in the inner electrode does not exceed 10wt%, or when the average content (wt%) of Ge relative to Ni in the inner electrode is in the range of from 0.1wt% to 10wt%, a multilayer capacitor having a higher MTTF value can be obtained.

[0137] (Table 3)

[0138]

[0139] Referring to Table 3, it can be seen that compared with Examples 4-1 to 4-4, Comparative Examples 4-1 and 4-2, whose values ​​exceed 0.20, have significantly lower MTTF values, and thus their reliability is not excellent. In addition, referring to Table 3, it can be seen that when When , a multilayer capacitor with a higher MTTF value can be obtained.

[0140] While the present disclosure has been described in conjunction with what are presently considered to be practical examples, it will be understood that the present disclosure is not limited to the disclosed examples. Rather, it 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 capacitor body including a dielectric layer and inner electrodes; as well as an outer electrode disposed on an outer side of the capacitor body, wherein the inner electrode comprises a Ni-Ge alloy, and When an average content of Ge relative to Ni based on weight percentage at a central portion of the inner electrode is represented by X, and an average content of Ge relative to Ni based on weight percentage at a point spaced 20 nm from an interface between the inner electrode and the dielectric layer toward the central portion of the inner electrode is represented by Y, a relationship between X and Y satisfies Expression 1: [Expression 1] 2. The multilayer capacitor according to claim 1, wherein An average content of Ge in the inner electrode relative to Ni is in the range of from 0.1 wt % to 10 wt %.

3. The multilayer capacitor according to claim 1, wherein The value of X ranges from 0.90 wt % to 1.80 wt %.

4. The multilayer capacitor according to claim 1, wherein The value of Y ranges from 1.00 wt% to 1.50 wt%.

5. The multilayer capacitor according to claim 1, wherein An average thickness of the inner electrode ranges from 0.05 μm to 1 μm.

6. The multilayer capacitor according to claim 1, wherein The average thickness of the dielectric layer ranges from 0.05 μm to 2.5 μm.

7. The multilayer capacitor according to claim 1, wherein The dielectric layer includes a dielectric including a main component and a sub component.

8. The multilayer capacitor according to claim 7, wherein The main components include: Ba m TiO3, where 0.995≤m≤1.10, (Ba 1-x Ca x ) m (Ti 1-y Zr y )O3, where 0.995≤m≤1.10, 0≤x≤0.10 and 0 <y≤0.20, Ba m (Ti 1-x Zr x )O3, where 0.995≤m≤1.10 and 0 <x≤0.10, (Ba 1-x Ca x ) m (Ti 1-y Sn y )O3, where 0.995≤m≤1.10, 0≤x≤0.10 and 0 <y≤0.20, or a combination thereof.

9. The multilayer capacitor according to claim 7, wherein The subcomponents include Dy, V, Mn, Cr, Si, Al, Mg, Sn, Sb, Ge, Ga, In, Ba, La, Y, Ac, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Ho, Er, Tm, Yb, Lu, Hf or a combination thereof.

10. The multilayer capacitor according to claim 2, wherein An average thickness of the inner electrode ranges from 0.05 μm to 1 μm.

11. The multilayer capacitor according to claim 10, wherein The average thickness of the dielectric layer ranges from 0.05 μm to 2.5 μm.

12. The multilayer capacitor according to claim 1, wherein 13. A multilayer capacitor comprising: a capacitor body including a dielectric layer and inner electrodes; as well as an outer electrode disposed on an outer side of the capacitor body, wherein the inner electrode comprises a Ni-Ge alloy, and The average content of Ge in the inner electrode relative to Ni is not more than 10 wt % based on weight percentage, and When an average content of Ge relative to Ni based on weight percentage at a central portion of the inner electrode is represented by X, and an average content of Ge relative to Ni based on weight percentage at a point spaced 20 nm from an interface between the inner electrode and the dielectric layer toward the central portion of the inner electrode is represented by Y, a relationship between X and Y satisfies Expression 1: [Expression 1] 14. The multilayer capacitor according to claim 13, wherein The value of X ranges from 0.90 wt % to 1.80 wt %.

15. The multilayer capacitor according to claim 13, wherein The value of Y ranges from 1.00 wt% to 1.50 wt%.

16. The multilayer capacitor according to claim 13, wherein An average thickness of the inner electrode ranges from 0.05 μm to 1 μm.

17. The multilayer capacitor according to claim 13, wherein The average thickness of the dielectric layer ranges from 0.05 μm to 2.5 μm.

18. The multilayer capacitor according to claim 13, wherein The dielectric layer includes a dielectric including a main component and a sub component.

19. The multilayer capacitor according to claim 18, wherein The main components include: Ba m TiO3, where 0.995≤m≤1.10, (Ba 1-x Ca x ) m (Ti 1-y Zr y )O3, where 0.995≤m≤1.10, 0≤x≤0.10 and 0 <y≤0.20,Ba m (Ti 1-x Zr x )O3, where 0.995≤m≤1.10 and 0 <x≤0.10, (Ba 1-x Ca x ) m (Ti 1-y Sn y )O3, where 0.995≤m≤1.10, 0≤x≤0.10 and 0 <y≤0.20, or a combination thereof.

20. The multilayer capacitor of claim 18, wherein: The subcomponents include Dy, V, Mn, Cr, Si, Al, Mg, Sn, Sb, Ge, Ga, In, BaLa, Y, Ac, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Ho, Er, Tm, Yb, Lu, Hf or a combination thereof.

21. The multilayer capacitor of claim 13, wherein: The average thickness of the inner electrode is in the range from 0.05 μm to 1 μm, and The average thickness of the dielectric layer ranges from 0.05 μm to 2.5 μm.

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