Multilayer ceramic electronic component
Patent Information
- Application Number
- PCT/JP2025/012036
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-03-26
- Publication Date
- 2026-10-01
Smart Images
Figure JP2025012036_01102026_PF_FP_ABST
Abstract
Description
Multilayer ceramic electronic component
[0001] The present invention relates to a multilayer ceramic electronic component.
[0002] When a multilayer ceramic electronic component is mounted on a wiring mounting substrate, it is generally mounted by a surface mounting method in which the terminal electrodes of the electronic component are directly soldered onto lands of the wiring mounting substrate.
[0003] However, mechanical stress may be applied to the electronic component due to stress generated by the difference in coefficient of thermal expansion between the wiring mounting substrate and the electronic component, stress generated by bending of the wiring mounting substrate, or the like, leading to problems such as cracking or peeling of the terminal electrodes from the electronic component body.
[0004] Further, in multilayer ceramic electronic components, materials having a relatively high dielectric constant such as barium titanate (referred to as "ferroelectric materials") are generally used.
[0005] However, ferroelectric materials have piezoelectricity and electrostriction. Therefore, when an electric field is applied to the ferroelectric material, stress and mechanical strain occur in the multilayer ceramic electronic component, which may cause the multilayer ceramic electronic component to vibrate. When the vibration of the multilayer ceramic electronic component is transmitted to the mounting substrate side through the terminal electrodes, the mounting substrate serves as an acoustic radiation surface, which may cause noise vibration (so-called acoustic noise).
[0006] In order to solve such problems, for example, according to Patent Document 1, terminal plates formed of elastic metal plates are respectively bonded to each terminal electrode. Each terminal electrode is mounted on the wiring mounting substrate via the terminal plate, respectively. This makes it possible to relieve stress applied to the multilayer ceramic electronic component and relieve stress applied to the mounting substrate.
[0007] Japanese Patent Laid-Open No. 2005-64377
[0008] However, if a crack occurs in a multilayer ceramic electronic component and the crack connects multiple internal electrode layers, a short circuit may occur. If a short circuit occurs, an overcurrent may flow, potentially causing further malfunctions such as overheating. The multilayer ceramic electronic component described in Patent Document 1 still has room for improvement in terms of countermeasures against overcurrent flow.
[0009] The present invention aims to provide a multilayer ceramic electronic component that, with a simple configuration, can prevent overcurrent from continuing to flow between metal terminals when the multilayer ceramic capacitor body is short-circuited due to a malfunction.
[0010] The multilayer ceramic electronic component according to the present invention comprises a laminate including a plurality of stacked ceramic layers and a plurality of internal conductor layers stacked on the ceramic layers, the laminate including a first main surface and a second main surface facing each other in the height direction, a first side surface and a second side surface facing each other in the width direction perpendicular to the height direction, and a first end surface and a second end surface facing each other in the length direction perpendicular to the height direction and the width direction; a multilayer ceramic electronic component body having a first external electrode disposed on the side of the first end surface and a second external electrode disposed on the side of the second end surface; a first metal terminal electrically connected to the first external electrode and a second metal terminal electrically connected to the second external electrode, further comprising a spring member electrically connecting the first external electrode and the first metal terminal, and a fuse disposed in a part between the first external electrode and the first metal terminal, wherein the spring member is disposed in a tensile state between the first external electrode and the first metal terminal.
[0011] According to the present invention, it is possible to provide a multilayer ceramic electronic component that, with a simple configuration, can prevent overcurrent from continuing to flow between metal terminals when the multilayer ceramic capacitor body is short-circuited due to a malfunction.
[0012] This is an external perspective view of a multilayer ceramic capacitor according to an embodiment. This is a cross-sectional view taken along line II-II in Figure 1. This is a view of the multilayer ceramic capacitor and the mounting substrate in the width direction. This is a diagram corresponding to Figure 3, showing the state in which the fuse is activated. This is a diagram showing the manufacturing method of a multilayer ceramic capacitor. This is a diagram showing the manufacturing method of a multilayer ceramic capacitor. This is a diagram showing the manufacturing method of a multilayer ceramic capacitor. This is a diagram showing the manufacturing method of a multilayer ceramic capacitor. This is a diagram showing the main body of a double-gang multilayer ceramic capacitor. This is a diagram showing the main body of a triple-gang multilayer ceramic capacitor. This is a diagram showing the main body of a quadruple-gang multilayer ceramic capacitor.
[0013] Hereinafter, a multilayer ceramic capacitor 1 as a multilayer ceramic electronic component according to an embodiment of this disclosure will be described with reference to the drawings. Figure 1 is an external perspective view of the multilayer ceramic capacitor 1 according to the embodiment. Figure 2 is a cross-sectional view taken along line II-II of Figure 1. Figure 3 is a view of the multilayer ceramic capacitor 1 and the mounting substrate 90 in the width direction W. Figure 4 is a diagram corresponding to Figure 3, showing the state in which the fuse H1 is activated.
[0014] The multilayer ceramic capacitor 1 is used by being mounted on a mounting substrate 90 having a pair of lands 91 provided on the mounting surface 90a (see Figure 3). The multilayer ceramic capacitor 1 has a multilayer ceramic capacitor body 10 as the main body of the multilayer ceramic electronic component, a first metal terminal 50A, and a second metal terminal 50B. The first metal terminal 50A and the second metal terminal 50B are sometimes collectively referred to as "metal terminal 50".
[0015] Furthermore, the drawings may be schematically simplified to illustrate the content of the invention, and the ratios of the dimensions of the depicted components or between components may not match the ratios of those dimensions described in the specification. In addition, components described in the specification may be omitted in the drawings, or their number may be omitted. For example, the number of internal electrode layers 14 described in Figure 2 is shown as 6 for the sake of explanation, but this does not represent the actual number of internal electrode layers 14. Furthermore, the terms used in this invention to specify shapes, geometric conditions, and their degree, such as terms like "parallel," "orthogonal," and "identical," as well as values of length and angle, should not be interpreted strictly, but rather as including a range that allows for the expectation of similar functionality.
[0016] (Multilayer ceramic capacitor body) As shown in Figure 1, the multilayer ceramic capacitor body 10 according to this embodiment has a substantially rectangular parallelepiped shape. The multilayer ceramic capacitor body 10 comprises a laminate 11 having a substantially rectangular parallelepiped shape, and a pair of external electrodes 30 arranged spaced apart from each other at both ends of the laminate 11.
[0017] In this specification, when the multilayer ceramic capacitor 1 is mounted on the mounting substrate 90, the direction in which the multilayer ceramic capacitor 1 and the mounting substrate 90 are aligned is defined as the "height direction T". The height direction T is also the direction perpendicular to the mounting surface of the mounting substrate 90. One of the directions perpendicular to the height direction T is defined as the "length direction L". The direction perpendicular to both the height direction T and the length direction L is defined as the "width direction W". The pair of lands 91 are aligned in the length direction L. The pair of external electrodes 30 are located at one end and the other end of the laminate 11 in the length direction L, respectively.
[0018] The laminate 11 includes a first main surface TS1 and a second main surface TS2 that are opposite to the height direction T, a first end surface LS1 and a second end surface LS2 that are opposite to the length direction L which is perpendicular to the height direction T, and a first side surface WS1 and a second side surface WS2 that are opposite to the width direction W which is perpendicular to the height direction T and the length direction L.
[0019] The first end face LS1 and the second end face LS2 are collectively referred to as "end face LS".
[0020] The laminate 11 has a substantially rectangular parallelepiped shape. The length L dimension of the laminate 11 is not necessarily longer than the width W dimension. It is preferable that the corners and edges of the laminate 11 are rounded. The corners are the points where three faces of the laminate intersect, and the edges are the points where two faces intersect. Furthermore, some or all of the surfaces constituting the laminate 11 may have irregularities or other features.
[0021] The dimensions of the laminate 11 are not particularly limited, but if the dimension in the length direction L of the laminate 11 is denoted as dimension L, then dimension L is preferably 2 mm or more and 6 mm or less. If the dimension in the height direction T of the laminate 11 is denoted as dimension T, then dimension T is preferably 0.5 mm or more and 3 mm. If the dimension in the width direction W of the laminate 11 is denoted as dimension W, then dimension W is preferably 1 mm or more and 5 mm or less. In the laminate 11, the dimension in the height direction T is preferably smaller than the dimension in the width direction W. In the laminate 11, the dimension in the height direction T is preferably smaller than the dimension in the length direction L. However, it is not limited to these.
[0022] As shown in Figure 2, the laminate 11 has an inner layer 12 inside. The inner layer 12 includes a plurality of stacked inner dielectric layers 13 (corresponding to ceramic layers) and a plurality of internal electrode layers 14 (corresponding to internal conductor layers) stacked on the inner dielectric layers 13. The direction in which the plurality of inner dielectric layers 13 are stacked is perpendicular to the length direction L, and is, for example, the height direction T. The inner layer 12 has a multilayer structure in which, for example, a plurality of internal electrode layers 14 and a plurality of inner dielectric layers 13 are stacked alternately. The four sides of the inner layer 12, both sides in the width direction W and both sides in the height direction T, are covered with an outer dielectric layer 16 made of the same material as the inner dielectric layers 13.
[0023] The internal electrode layer 14 is made of a suitable conductive material such as a metal such as Ni, Cu, Ag, Pd, or Au, or an alloy containing at least one of these metals. When an alloy is used, the first internal electrode layer 31 and the second internal electrode layer 32 may be made of, for example, an Ag-Pd alloy.
[0024] The inner dielectric layer 13 and the outer dielectric layer 16 are formed by firing a dielectric material. The dielectric material is, for example, BaTiO ３ CaTiO ３ SrTiO ３ , or CaZrO ３ The dielectric ceramic may contain components such as the above. Alternatively, the dielectric material may have minor components such as Mn compounds, Fe compounds, Cr compounds, Co compounds, and Ni compounds added to these main components. The dielectric material may have BaTiO as its main component. ３ It is particularly preferable that the material contains [a specific substance].
[0025] A pair of external electrodes 30 are positioned at both ends of the laminate 11 in the longitudinal direction L. Each external electrode 30 covers a pair of end faces LS of the laminate 11. In the multiple internal electrode layers 14 of the inner layer 12, for example, one side of adjacent internal electrode layers 14 in the thickness direction T is connected to one external electrode 30, and the other side is connected to the other external electrode 30. Of the pair of external electrodes 30, the external electrode 30 positioned on the first end face LS1 side is referred to as the "first external electrode 30A," and the external electrode 30 positioned on the second end face LS2 side is referred to as the "second external electrode 30B."
[0026] The external electrode 30 is composed of, for example, a laminated film of a sintered metal layer and a plating layer. The sintered metal layer is formed by baking a paste of, for example, Cu, Ni, Ag, Pd, Ag-Pd alloy, Au, etc. The plating layer is composed of, for example, a Ni plating layer and a Sn plating layer covering it.
[0027] The external electrode 30 in this embodiment may, for example, have a conductive resin layer containing a metal filler and a thermosetting resin. The conductive resin layer may be arranged to cover the baking layer. When the conductive resin layer is arranged to cover the baking layer, it is positioned between the baking layer and the plating layer. The conductive resin layer may completely cover the baking layer or cover only a portion of it.
[0028] A conductive resin layer containing a thermosetting resin is more flexible than a conductive layer made of, for example, a plated film or a fired conductive paste. Therefore, even if the multilayer ceramic capacitor body 10 is subjected to physical shock or shock caused by thermal cycling, the conductive resin layer functions as a buffer layer. Thus, the conductive resin layer suppresses the occurrence of cracks in the multilayer ceramic capacitor body 10.
[0029] The above describes the basic configuration of the multilayer ceramic capacitor body 10 according to the embodiment. If the length L dimension of the multilayer ceramic capacitor body 10, including the laminate 11 and the external electrodes 30, is denoted as dimension L, then dimension L is preferably 2 mm to 6 mm. Furthermore, if the height T dimension of the multilayer ceramic capacitor 1 is denoted as dimension T, then dimension T is preferably 0.5 mm to 3 mm. Also, if the width W dimension of the multilayer ceramic capacitor 1 is denoted as dimension W, then dimension W is preferably 1 mm to 5 mm.
[0030] The multilayer ceramic capacitor body 10 is manufactured, for example, by firing the laminate 11, and then forming a pair of external electrodes 30 by baking, plating, or the like. In some cases, a portion of the external electrodes 30 may be fired simultaneously with the laminate 11, and then a plating layer, for example, of the external electrodes 30 may be formed later.
[0031] (Metal terminals) As shown in Figure 3, each of the metal terminals 50 is a metal terminal mounted on the mounting surface 90a (more specifically, the land 91) of the mounting substrate 90. Each of the metal terminals 50 is, for example, a plate-shaped lead frame. Each of the metal terminals 50 is formed, for example, by bending a rectangular plate-shaped lead frame. Of the ends of the metal terminal 50 in the height direction T, the end closer to the mounting surface 90a is sometimes called the "base end," and the end further from the mounting surface 90a is sometimes called the "tip end."
[0032] The first metal terminal 50A is electrically connected to the first external electrode 30A. The first metal terminal 50A has, for example, a first joint portion 51A that faces the first end face LS1 and is electrically connected to the first external electrode 30A, and extends in the height direction T toward the mounting substrate 90; a first mounting portion 52A that extends in the length direction L toward the second metal terminal 50B from the end of the first joint portion 51A closer to the mounting substrate 90 and is connected to the land 91; a first rising portion 53A that extends in the height direction T toward away from the mounting substrate 90 from the end of the first mounting portion 52A closer to the second metal terminal 50B; and a first opposing portion 55A that extends in the length direction L toward the first joint portion 51A from the end of the first rising portion 53A farther from the mounting substrate 90 and faces the multilayer ceramic capacitor body 10 in the height direction T. The multilayer ceramic capacitor body 10 and the first opposing portion 55A are spaced apart.
[0033] The second metal terminal 50B is electrically connected to the second external electrode 30B. The second metal terminal 50B includes, for example, a second joint portion 51B that faces the second end face LS2 and is electrically connected to the second external electrode 30B, extending in the height direction T toward the mounting substrate 90; a second mounting portion 52B that extends in the length direction L toward the first metal terminal 50A from the end of the second joint portion 51B closer to the mounting substrate 90 and is connected to the land 91; a second rising portion 53B that extends in the height direction T toward away from the mounting substrate 90 from the end of the second mounting portion 52B closer to the first metal terminal 50A; and a second opposing portion 55B that extends in the length direction L toward approaching the second joint portion 51B from the end of the second rising portion 53B farther from the mounting substrate 90 and faces the multilayer ceramic capacitor body 10 in the height direction T. The multilayer ceramic capacitor body 10 and the second opposing portion 55B are spaced apart.
[0034] Here, the multilayer ceramic capacitor 1 further comprises a spring member 60 that electrically connects the first external electrode 30A and the first metal terminal 50A, and a fuse H1 disposed in a portion of the space between the first external electrode 30A and the first metal terminal 50A.
[0035] The spring member 60 is positioned in a tensile state between the first external electrode 30A and the first metal terminal 50A. "Tensile state" refers to a state in which the spring member 60 is stretched beyond its natural length due to tensile stress.
[0036] More specifically, the spring member 60 is positioned between the first external electrode 30A and the first metal terminal 50A (more precisely, the first joint 51A). The spring member 60 has tensile elasticity in the longitudinal direction L. The spring member 60 is made of, for example, stainless steel. The spring member 60 is, for example, a leaf spring. The spring member 60 is, for example, formed by bending a rectangular plate. If the spring member 60 is in the shape of a coil, there is a risk of inductor components being generated. However, by having the spring member 60 in the shape of a plate, the generation of inductor components can be suppressed. The spring member 60 has, for example, a body-side opposing portion 61, a connecting portion 62, and a terminal-side opposing portion 63.
[0037] The body-side opposing portion 61 opposes the first external electrode 30A in the length direction L. The body-side opposing portion 61 extends in the height direction T.
[0038] The connecting portion 62 extends in the length direction L from the substrate-side end of the body-side opposing portion 61. An intermediate portion of the connecting portion 62 in the length direction L is bent, for example, so as to protrude toward the substrate side. The connecting portion 62 has a V-shape, for example.
[0039] The terminal-side opposing portion 63 extends, from an end, which is farther from the multilayer ceramic capacitor body 10 among the respective ends of the connecting portion 62 in the length direction L, in a direction away from the mounting surface 90a in the height direction T. The terminal-side opposing portion 63 opposes the first metal terminal 50A (specifically, the first joining portion 51A) in the length direction L.
[0040] The fuse H1 is disposed between the first external electrode 30A and the first metal terminal 50A. The fuse H1 is disposed, for example, between the first external electrode 30A and the spring member 60 (specifically, the body-side opposing portion 61). The spring member 60 is connected to the fuse H1, more specifically, connected via the fuse H1. When the fuse H1 is activated, the electrical connection between the first external electrode 30A and the first metal terminal 50A is cut off. The fuse H1 melts by heat, for example.
[0041] The multilayer ceramic capacitor 1 further includes, for example, a second solder H2 that connects the second external electrode 30B and the second metal terminal 50B. The second external electrode 30B is connected to the second metal terminal 50B (specifically, the second joining portion 51B), for example, via the second solder H2.
[0042] In addition, the fuse H1 is constituted, for example, by a first solder H1 having a lower melting point than that of the second solder H2. The first solder H1 connects the first external electrode 30A and the spring member 60. Note that the fuse H1 may sometimes be referred to as "the first solder H1".
[0043] Furthermore, a third solder H3 is disposed between the spring member 60 (more specifically, the terminal-side opposing portion 63) and the first metal terminal 50A (more specifically, the first joint portion 51A). The spring member 60 is connected to the first metal terminal 50A, more specifically, connected via the third solder H3. The melting point of the third solder H3 is, for example, higher than the melting point of the first solder H1.
[0044] Note that the melting point (solidus temperature) of the first solder H1 is, for example, not lower than 140°C and not higher than 190°C, preferably not lower than 140°C and not higher than 160°C.
[0045] The melting point (solidus temperature) of the second solder H2 is, for example, higher than 190°C and not higher than 250°C, preferably not lower than 210°C and not higher than 250°C, and more preferably not lower than 230°C and not higher than 250°C.
[0046] If the difference between the melting point of the first solder H1 and the melting point of the second solder H2 is too small, there is a risk that the second solder H2 will melt together with the first solder H1 when the multilayer ceramic capacitor 1 is overheated. Therefore, the difference between the melting point (solidus temperature) of the first solder H1 and the melting point (solidus temperature) of the second solder H2 is, for example, not less than 20°C, and preferably not less than 70°C. This can suppress the melting of the second solder H2 together with the first solder H1 when the multilayer ceramic capacitor 1 is overheated.
[0047] The melting point of the third solder H3 is also the same as that of the second solder H2. However, the melting points of the first solder H1, the second solder H2, and the third solder H3 are not limited to these, and can be appropriately changed in consideration of the environment in which the multilayer ceramic capacitor 1 is used.
[0048] In addition, the metals constituting the first solder H1, the second solder H2, and the third solder H3 are not particularly limited, and are selected from, for example, common metals that constitute solder.
[0049] The multilayer ceramic capacitor 1 further includes, for example, an insulating member 70 positioned on the mounting surface 90a side of the multilayer ceramic capacitor body 10 and the spring member 60.
[0050] The insulating member 70 is positioned between the multilayer ceramic capacitor body 10 and the spring member 60 and the mounting surface 90a. The insulating member 70 is positioned between the first metal terminal 50A and the second metal terminal 50B. The insulating member 70 is positioned, for example, on the side of the multilayer ceramic capacitor body 10 that is closer to the first opposing portion 55A and the second opposing portion 55B. The insulating member 70 is positioned, for example, opposite the first opposing portion 55A and the second opposing portion 55B in the height direction T. The insulating member 70 is fixed to the first opposing portion 55A and the second opposing portion 55B by an adhesive G1. The adhesive G1 is, for example, an epoxy adhesive, but is not limited to this. The insulating member 70 is in contact with the first joint portion 51A and the second joint portion 51B, respectively. The insulating member 70 defines the distance between the first metal terminal 50A and the second metal terminal 50B. The insulating member 70 is, for example, a flat plate with a plate surface extending in the length direction L and the width direction W. The material forming the insulating member 70 is not particularly limited as long as it has insulating properties, but a glass epoxy material is preferred.
[0051] The insulating member 70 is, for example, positioned at a distance T in the height direction from the multilayer ceramic capacitor body 10.
[0052] The insulating member 70 connects, for example, the central region when the first metal terminal 50A is divided into three equal parts in the height direction T, and the central region when the second metal terminal 50B is divided into three equal parts in the height direction T.
[0053] As shown in Figure 5D, an inclined portion 70a is formed at one end of the insulating member 70 in the width direction W. The inclined portion 70a is tapered, for example, with the length L increasing as it moves from one side in the width direction W to the other.
[0054] The length L dimension of the insulating member 70 is, for example, larger than the length L dimension of the multilayer ceramic capacitor body 10. More specifically, it is larger than the sum of the length L dimension of the multilayer ceramic capacitor body 10, the length L dimension of the fuse H1, and the length L dimension of the spring member when no tensile stress is acting on it. More specifically, it is larger than the sum of the length L dimension of the second solder H2, the length L dimension of the multilayer ceramic capacitor body 10, the length L dimension of the fuse H1, the length L dimension of the spring member when no tensile stress is acting on it, and the length L dimension of the third solder H3. The length L dimension of the insulating member 70 corresponds, for example, to the distance in the length L between a pair of lands 91.
[0055] When the multilayer ceramic capacitor 1 is mounted on the mounting substrate 90, each of the metal terminals 50 is connected to a land 91 provided on the mounting surface 90a. Each of the metal terminals 50 is connected to the land 91, for example, by mounting solder H4. Preferably, the melting point of the mounting solder H4 is lower than the melting point of the first solder H1. Note that the method of connecting the metal terminals 50 to the land 91 is not limited to soldering and can be changed as appropriate.
[0056] (Operation of Multilayer Ceramic Capacitor) Next, the operation of the multilayer ceramic capacitor 1 will be explained. Figure 4 is a diagram corresponding to Figure 3, and shows the state in which the fuse has been activated.
[0057] When the multilayer ceramic capacitor 1 is mounted on the mounting board 90, the first metal terminal 50A and the multilayer ceramic capacitor body 10 are electrically connected via the third solder H3, the spring member 60, and the fuse H1 (first solder H1), and the second metal terminal 50B and the multilayer ceramic capacitor body 10 are electrically connected via the second solder H2.
[0058] If a short circuit occurs in the multilayer ceramic capacitor body 10, causing the temperature of the multilayer ceramic capacitor body 10 to rise above a certain level, the fuse H1 (first solder H1) will melt. At this time, since the melting point of the first solder H1 is lower than the melting points of the second solder H2 and the third solder H3, the second solder H2 and the third solder H3 will not melt.
[0059] As shown in Figure 4, when the first solder H1 melts, the end of the spring member 60 on the multilayer ceramic capacitor body 10 side moves toward the first metal terminal 50A side due to the tensile elasticity of the spring member 60. As a result, the connection between the spring member 60 and the multilayer ceramic capacitor body 10 is released, and the current to the multilayer ceramic capacitor body 10 is stopped.
[0060] (Method for Manufacturing Multilayer Ceramic Capacitors) Next, the method for manufacturing the multilayer ceramic capacitor 1 of this embodiment will be described. The method for manufacturing the multilayer ceramic capacitor 1 of this embodiment is not limited as long as the above requirements are satisfied. However, a preferred manufacturing method comprises the following steps. The details of each step will be described below. Figures 5A to 5D are diagrams showing the method for manufacturing multilayer ceramic capacitors. Figure 5D is a plan view of the multilayer ceramic capacitor 1 without the insulating member 70 and the insulating member 70, viewed from the multilayer ceramic capacitor 1 side toward the mounting substrate 90 side in the height direction T. In Figure 5, for the convenience of explanation, the second solder H2, the multilayer ceramic capacitor body 10, the fuse H1, the spring member 60, and the third solder H3 are shown by dashed lines.
[0061] As shown in Figure 5A, a high-melting-point solder, which is the second solder H2, is placed on the second joint 51B of the second metal terminal 50B. The second external electrode 30B is placed on the second solder H2. The second solder H2 is reflowed. As a result, the second metal terminal 50B and the second external electrode 30B are connected by the second solder H2.
[0062] As shown in Figure 5B, a high-melting-point solder, which is the third solder H3, is placed on the first joint 51A of the first metal terminal 50A. The terminal-side opposing portion 63 of the spring member 60 is placed on the third solder H3. The third solder H3 is reflowed. As a result, the first metal terminal 50A and the spring member 60 are connected by the third solder H3. Next, a low-melting-point solder, which is the first solder H1, is placed on the body-side opposing portion 61 of the spring member 60.
[0063] As shown in Figure 5C, the first external electrode 30A and the first solder H1 are in contact. The first solder H1 is reflowed. As a result, the first external electrode 30A and the spring member 60 are connected by the first solder H1.
[0064] The melting point of the first solder H1 is lower than that of the second solder H2 and the third solder H3. To prevent the first solder H1 from melting during the reflow of the second solder H2 or the third solder H3, the first solder H1 is used last among the first solder H1, the second solder H2, and the third solder H3.
[0065] Next, adhesive material G1 is applied to the first opposing portion 55A of the first metal terminal 50A and the second opposing portion 55B of the second metal terminal 50B.
[0066] As shown in Figure 5D, the insulating member 70 is inserted between the first metal terminal 50A and the second metal terminal 50B. When the insulating member 70 is not attached to the multilayer ceramic capacitor 1, the distance in the longitudinal direction L between the first joint 51A of the first metal terminal 50A and the second joint 51B of the second metal terminal 50B is smaller than the length L of the insulating member 70. The first joint 51A and the second joint 51B are pulled apart in the longitudinal direction L. In this state, the insulating member 70 is inserted into the area between the first joint 51A and the second joint 51B that is on the mounting surface 90a side of the multilayer ceramic capacitor body 10 and the spring member 60.
[0067] The insulating member 70 is inserted, for example, between the first joint 51A and the second joint 51B from the other side in the width direction W toward one side in the width direction W. At this time, an inclined portion 70a is formed on the edge of the insulating member 70 on one side in the width direction W. This allows the insulating member 70 to be smoothly inserted between the first joint 51A and the second joint 51B while widening the gap between them. Next, the insulating member 70 is bonded to the first opposing portion 55A and the second opposing portion 55B with adhesive G1.
[0068] The length L of the insulating member 70 is greater than the sum of the length L of the second solder H2, the length L of the multilayer ceramic capacitor body 10, the length L of the fuse H1, the length L of the spring member 60 when no tensile stress is acting on it, and the length L of the third solder H3. As a result, even when the multilayer ceramic capacitor 1 is not mounted on the mounting board 90, the distance between the metal terminals 50 is maintained at a distance that causes the spring member 60 to be under tension.
[0069] Furthermore, the multilayer ceramic capacitor 1 is mounted on the mounting substrate 90 using, for example, mounting solder H4. Since the melting point of the first solder H1 is relatively low, it is undesirable if the first solder H1 were to melt during the reflow of the mounting solder H4. However, by placing a spring member 60 between the first solder H1 and the first metal terminal 50A, it is possible to suppress the melting of the insulating member 70 when mounting the multilayer ceramic capacitor 1. In addition, since the spring member 60 is made of stainless steel, which has a relatively low thermal conductivity, the transfer of heat from the first metal terminal 50A to the first solder H1 can be suitably suppressed. Furthermore, since the melting point of the second solder H2 is relatively high, it is possible to suppress the melting of the second solder H2 when mounting the multilayer ceramic capacitor 1.
[0070] Through the above manufacturing process, a multilayer ceramic capacitor 1 is produced.
[0071] Note that the configuration of the multilayer ceramic capacitor body 10 is not limited to the configuration shown in Figure 2. For example, the multilayer ceramic capacitor body 10 may be a double-gang, triple-gang, or quadruple-gang multilayer ceramic capacitor body as shown in Figures 6A, 6B, and 6C.
[0072] The multilayer ceramic capacitor body 10 shown in Figure 6A is a double-gang multilayer ceramic capacitor body, and as internal electrode layers 14, it includes an internal electrode layer 14 drawn out to the first end face LS1, an internal electrode layer 14 drawn out to the second end face LS2, and a floating internal electrode layer 15 (corresponding to an internal conductor layer) that is not drawn out to either the first end face LS1 or the second end face LS2. The multilayer ceramic capacitor body 10 shown in Figure 6B is a triple-gang multilayer ceramic capacitor body 10, which includes a first floating internal electrode layer 15A and a second floating internal electrode layer 15B as floating internal electrode layers 15. The multilayer ceramic capacitor body 10 shown in Figure 6C is a quadruple-gang multilayer ceramic capacitor body 10, which includes a first floating internal electrode layer 15A, a second floating internal electrode layer 15B, and a third floating internal electrode layer 15C as floating internal electrode layers 15. In this way, by providing a floating internal electrode layer 15 as the internal electrode layer 14, the multilayer ceramic capacitor body 10 has a structure in which the opposing electrode portion is divided into multiple parts. As a result, multiple capacitor components are formed between the opposing internal electrode layers 14, and these capacitor components are connected in series. Therefore, the voltage applied to each capacitor component becomes lower, and the voltage withstand capability of the multilayer ceramic capacitor body 10 can be increased. It goes without saying that the multilayer ceramic capacitor body 10 of this embodiment may also have a multi-gang structure of four or more units.
[0073] In the embodiments described above, a multilayer ceramic capacitor body was exemplified as the multilayer ceramic electronic component body, in which an inner dielectric layer 13 and an outer dielectric layer 16, both made of dielectric ceramic, are used as ceramic layers. However, the multilayer ceramic electronic component body of this disclosure is not limited to this. For example, the ceramic electronic component body of this disclosure can also be applied to various multilayer ceramic electronic component bodies such as piezoelectric components using piezoelectric ceramics as ceramic layers, and thermistors using semiconductor ceramics as ceramic layers. Examples of piezoelectric ceramics include PZT (lead zirconate titanate) ceramics, and examples of semiconductor ceramics include spinel ceramics.
[0074] The multilayer ceramic capacitor 1 according to the embodiment described above provides the following effects.
[0075] The multilayer ceramic capacitor 1 according to this embodiment includes a plurality of stacked inner dielectric layers 13 and a plurality of internal electrode layers 14 stacked on the inner dielectric layers 13, and a laminate 11 including a first main surface TS1 and a second main surface TS2 facing the height direction T, a first side surface WS1 and a second side surface WS2 facing the width direction W perpendicular to the height direction T, and a first end surface LS1 and a second end surface LS2 facing the length direction L perpendicular to the height direction T and the width direction W, a first external electrode 30A disposed on the first end surface LS1 side, and a second external electrode 30B disposed on the second end surface LS2 side. A multilayer ceramic capacitor comprising a multilayer ceramic capacitor body 10 having a first external electrode 30A and a first metal terminal 50A electrically connected to the first external electrode 30A and a second metal terminal 50B electrically connected to the second external electrode 30B, further comprising a spring member 60 electrically connecting the first external electrode 30A and the first metal terminal 50A, and a fuse H1 disposed in a part between the first external electrode 30A and the first metal terminal 50A, wherein the spring member 60 is disposed in a tensile state between the first external electrode 30A and the first metal terminal 50A.
[0076] With this configuration, it is possible to provide a multilayer ceramic capacitor 1 that can prevent overcurrent from continuing to flow between the metal terminals 50 when the multilayer ceramic capacitor body 10 is short-circuited due to a malfunction.
[0077] In the multilayer ceramic capacitor 1 according to this embodiment, a second solder H2 is further provided to connect the second external electrode 30B and the second metal terminal 50B, and the fuse H1 is made of a first solder H1 having a lower melting point than the second solder H2.
[0078] With this configuration, by soldering the components of the multilayer ceramic capacitor 1 using solder having the melting point relationship described above, it is possible to reliably operate it as a fuse with a simple configuration. Furthermore, when the fuse H1 (first solder H1) melts, it is easier to maintain the state in which the second external electrode 30B and the second metal terminal 50B are connected by the second solder H2. Therefore, it is possible to suppress the multilayer ceramic capacitor 1 from falling when the fuse H1 is activated.
[0079] In the multilayer ceramic capacitor 1 according to this embodiment, the first solder H1 connects the first external electrode 30A and the spring member 60.
[0080] With this configuration, heat from the multilayer ceramic capacitor 1 can be easily transferred to the first solder H1. This allows the fuse H1 to activate quickly when the multilayer ceramic capacitor 1 overheats.
[0081] In the multilayer ceramic capacitor 1 according to this embodiment, a third solder H3 is further provided to connect the spring member 60 and the first metal terminal 50A, and the fuse H1 is made of the first solder H1 which has a lower melting point than the third solder H3.
[0082] With this configuration, by soldering the components of the multilayer ceramic capacitor 1 using solder having the melting point relationship described above, it is possible to reliably operate it as a fuse with a simple configuration. Furthermore, when the fuse H1 (first solder H1) melts, it is possible to easily maintain the state in which the spring member 60 and the first metal terminal 50A are connected by the third solder H3. Therefore, it is possible to suppress the spring member 60 from falling off when the fuse H1 is activated.
[0083] In the multilayer ceramic capacitor 1 according to this embodiment, the spring member 60 is a leaf spring.
[0084] With this configuration, the contact area when joining the spring member 60 to other parts can be more easily secured compared to the case where the spring member 60 is, for example, a coil spring. Also, the current path can be more easily shortened compared to the case where the spring member 60 is, for example, a coil spring. As a result, the ESR can be more easily improved.
[0085] In the multilayer ceramic capacitor 1 according to this embodiment, an insulating member 70 is further provided, which is positioned on the mounting surface 90a side of the multilayer ceramic capacitor body 10 and the spring member 60.
[0086] With this configuration, it is possible to prevent the multilayer ceramic capacitor body 10 from falling off onto the mounting substrate 90.
[0087] Furthermore, since the metal terminals 50 can be prevented from coming into close proximity when the fuse H1 is activated, it becomes easier to secure a discharge prevention space between the metal terminals 50.
[0088] In the multilayer ceramic capacitor 1 according to this embodiment, the insulating member 70 is arranged at a distance from the multilayer ceramic capacitor body 10.
[0089] With this configuration, it is possible to suppress the transmission of vibrations from the multilayer ceramic capacitor 1 to the insulating member 70, thereby suppressing noise.
[0090] In the multilayer ceramic capacitor 1 according to this embodiment, the first metal terminal 50A is positioned on the mounting surface 90a side of the insulating member 70 and has a first opposing portion 55A that faces the insulating member 70 in the height direction T, and the second metal terminal 50B is positioned on the mounting surface 90a side of the insulating member 70 and has a second opposing portion 55B that faces the insulating member 70 in the height direction T.
[0091] With this configuration, the insulating member 70 can be supported by the first opposing portion 55A and the second opposing portion 55B, making it easier to place the insulating member 70 in the multilayer ceramic capacitor 1.
[0092] The present invention is not limited to the configuration of the above embodiments, and can be modified and applied as appropriate without altering the essence of the invention. Furthermore, a combination of two or more of the individual desirable configurations described in the above embodiments also constitutes the present invention.
[0093] For example, in the above embodiment, the spring member 60 was a leaf spring, but the type of spring member is not particularly limited. The spring member may be, for example, a coil spring.
[0094] In the above embodiment, the fuse H1 was solder, but it is not limited to this. The fuse H1 may be, for example, a conductive thermoplastic adhesive. A conductive thermoplastic adhesive is, for example, an adhesive in which a conductive filler containing a metal such as Ag is added to a thermoplastic resin such as polyethylene, polypropylene, polyamide, or polystyrene.
[0095] In the above embodiment, the external electrode 30B of the multilayer ceramic capacitor 2 and the second metal terminal 50B were connected by soldering, but the method of connecting the second external electrode 30B and the second metal terminal 50B is not particularly limited. The method of connecting the second external electrode 30B and the second metal terminal 50B may be, for example, bonding with a thermosetting conductive adhesive. A thermosetting conductive adhesive is, for example, an adhesive in which a conductive filler containing a metal such as Ag is added to a thermosetting resin such as epoxy resin. Since the thermosetting conductive adhesive hardens with heat, it can maintain its adhesive strength even at the heat resistance temperature of the components constituting the fuse H1, for example, at the melting point of the thermoplastic adhesive. Therefore, by connecting the second external electrode 30B and the second metal terminal 50B with a thermosetting conductive adhesive, it is possible to suppress the disconnection of the connection between the second external electrode 30B and the second metal terminal 50B due to heat when the fuse H1 is activated. Thus, when the fuse H1 is made of a thermoplastic adhesive and the second external electrode 30B and the second metal terminal 50B are made of a thermosetting conductive adhesive, the melting point of the thermoplastic adhesive constituting the fuse is lower than the heat resistance temperature of the thermosetting conductive adhesive bonding the second external electrode 30B and the second metal terminal 50B.
[0096] In the above embodiment, the spring member 60 and the first metal terminal 50A were connected by soldering, but the method of connecting the spring member 60 and the first metal terminal 50A is not particularly limited. The method of connecting the spring member 60 and the first metal terminal 50A may be, for example, bonding with a conductive adhesive. In that case, it is possible to suppress the connection between the spring member 60 and the first metal terminal 50A from being released by heat when the fuse H1 is activated. Note that if the fuse is made of a thermoplastic adhesive and the spring member 60 and the first metal terminal 50A are made of a conductive adhesive, the melting point of the thermoplastic adhesive making up the fuse is lower than the melting point of the conductive adhesive bonding the spring member 60 and the first metal terminal 50A.
[0097] In the above embodiment, the metal terminal 50 and the land 91 were connected by soldering, but the method of connecting the metal terminal 50 and the land 91 is not particularly limited. The method of connecting the metal terminal 50 and the land 91 may be, for example, bonding with a conductive adhesive. In that case, the metal terminal 50 and the land 91 can be bonded at a relatively low temperature, which can suppress the melting of the fuse H1 when mounting the multilayer ceramic capacitor 1.
[0098] In the above embodiment, the direction in which the multiple internal electrode layers 14 are stacked is the height direction T, but the direction in which the multiple internal electrode layers 14 are stacked may also be the width direction W. In the above embodiment, one spring member 60 is provided in one multilayer ceramic capacitor 1, but there may be multiple spring members 60 provided in one multilayer ceramic capacitor 1. The multiple spring members 60 may be arranged in parallel or in series.
[0099] In the above embodiment, the fuse H1 was positioned between the multilayer ceramic capacitor 1 and the spring member 60, but the position in which the fuse H1 is positioned is not limited to this. The fuse H1 may be positioned, for example, between the spring member 60 and the first metal terminal 50A. Also, in a configuration in which a plurality of spring members 60 are connected in series, the fuse H1 may be positioned between adjacent spring members 60.
[0100] 1 Multilayer ceramic capacitor (multilayer ceramic electronic component) 10 Multilayer ceramic capacitor body (multilayer ceramic electronic component body) 11 Laminate 13 Dielectric layer (ceramic layer) 14 Internal electrode layer (internal conductor layer) 15 Floating internal electrode layer (internal conductor layer) 30A First external electrode 30B Second external electrode 50A First metal terminal 50B Second metal terminal 60 Spring member 70 Insulating member H1 Fuse and first solder H2 Second solder L Length direction T Height direction W Width direction LS1 First end face LS2 Second end face TS1 First main surface TS2 Second main surface WS1 First side surface WS2 Second side surface
Claims
1. A multilayer ceramic electronic component comprising: a laminate including a plurality of stacked ceramic layers and a plurality of internal conductor layers stacked on the ceramic layers, the laminate including a first main surface and a second main surface facing each other in the height direction, a first side surface and a second side surface facing each other in the width direction perpendicular to the height direction, and a first end surface and a second end surface facing each other in the length direction perpendicular to the height direction and the width direction; a multilayer ceramic electronic component body having a first external electrode disposed on the side of the first end surface and a second external electrode disposed on the side of the second end surface; a first metal terminal electrically connected to the first external electrode; and a second metal terminal electrically connected to the second external electrode, further comprising: a spring member electrically connecting the first external electrode and the first metal terminal; and a fuse disposed in a part between the first external electrode and the first metal terminal, wherein the spring member is disposed in a tensile state between the first external electrode and the first metal terminal.
2. The multilayer ceramic electronic component according to claim 1, further comprising a second solder connecting the second external electrode and the second metal terminal, wherein the fuse is composed of a first solder having a lower melting point than the second solder.
3. The multilayer ceramic electronic component according to claim 2, wherein the first solder connects the first external electrode and the spring member.
4. The multilayer ceramic electronic component according to any one of claims 1 to 3, further comprising a third solder connecting the spring member and the first metal terminal, wherein the fuse is made of the first solder having a lower melting point than the third solder.
5. The multilayer ceramic electronic component according to any one of claims 1 to 4, wherein the spring member is a leaf spring.
6. The multilayer ceramic electronic component according to any one of claims 1 to 5, further comprising an insulating member disposed on the mounting surface side of the multilayer ceramic electronic component body and the spring member.
7. The multilayer ceramic electronic component according to claim 6, wherein the insulating member is arranged at a distance from the multilayer ceramic electronic component body.
8. The multilayer ceramic capacitor according to claim 6 or 7, wherein the first metal terminal is positioned on the mounting side of the insulating member and has a first opposing portion that faces the insulating member in the height direction, and the second metal terminal is positioned on the mounting side of the insulating member and has a second opposing portion that faces the insulating member in the height direction.