A multilayer ceramic capacitor

Abstract

This invention discloses a multilayer ceramic capacitor, comprising: a ceramic body, a first external electrode, and a second external electrode. The ceramic body includes multiple stacked dielectric layers and alternately stacked first and second internal electrodes, serving as a first main surface for mounting the multilayer ceramic capacitor. The first external electrode includes a first conductive layer on the ceramic body, a first solder layer on the first conductive layer, a first vibration buffer layer on the ceramic body, and a second solder layer on the first vibration buffer layer, with a second region close to the first main surface. The second external electrode includes a second conductive layer on the ceramic body, a third solder layer on the second conductive layer, a second vibration buffer layer on the ceramic body, and a fourth solder layer on the second vibration buffer layer, with a fourth region close to the first main surface. The first and second vibration buffer layers can reduce stress damage to the ceramic body and prevent the ceramic body from fracture.

Description

Technical Field

[0001] This invention relates to the field of capacitor technology, and more particularly to a multilayer ceramic capacitor. Background Technology

[0002] Multilayer ceramic capacitors (MLCCs) are typically soldered directly onto a circuit board. When energized, the electrostrictive effect causes tensile stress in the ceramic body, which is transmitted to the circuit board through the external electrodes. This causes the circuit board to vibrate, generating noise. If the vibration amplitude is large or the vibration duration is too long, the MLCC may detach from the circuit board or the ceramic body may be damaged. Additionally, bending or deformation of the circuit board also generates stress, which can easily cause the MLCC to detach from the circuit board or the ceramic body to break. As shown in Chinese patent CN109585168B, although it discloses that the second electrode layer E2 is made of conductive resin and can absorb external forces to act as a buffer, thereby suppressing cracks in the substrate, the second electrode layer E2 is formed outside the first electrode layer E1 (such as Cu, Ni) and inside the third electrode layer E3 (Ni). On the one hand, it is not directly bonded to the ceramic body. Therefore, when the ceramic body undergoes electrostriction, the ceramic body and the first electrode layer E1 are prone to separation or cracking at the welding position, which will affect the bonding force and conductivity between the external electrode and the ceramic body. On the other hand, the third electrode layer E3 is also a hard metal layer. When the circuit board is bent and deformed, the third electrode layer E3 (the tin layer will melt) is prone to separation or splitting from the circuit board. Moreover, the conductive resin layer in this patent is partially coated between the nickel layer and the copper layer, which will also affect the bonding force between the two and the consistency and stability of electrical performance. Summary of the Invention

[0003] The purpose of this invention is to provide a multilayer ceramic capacitor with a vibration buffer layer on the ceramic body. When the multilayer ceramic capacitor vibrates due to electrostriction or the circuit board deforms and generates stress, the vibration buffer layer can reduce the damage to the ceramic body caused by vibration and stress, and prevent the ceramic body from breaking.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A multilayer ceramic capacitor, comprising:

[0006] The ceramic body has a first main surface and a second main surface opposite to each other in the stacking direction, a first end surface and a second end surface opposite to each other in the length direction, and a first side surface and a second side surface opposite to each other in the width direction. The first main surface is the mounting surface of the multilayer ceramic capacitor. The ceramic body includes a plurality of stacked dielectric layers and alternating stacked first inner electrode and second inner electrode. The dielectric layer is located between the first inner electrode and the second inner electrode.

[0007] A first external electrode, at least a portion of which is located on the first end face, the first external electrode includes a first region and a second region, the first region includes a first conductive layer on the ceramic body and a first welding layer outside the first conductive layer, the first conductive layer being electrically connected to the first internal electrode, the second region including a first vibration buffer layer on the ceramic body and a second welding layer outside the first vibration buffer layer, the second region being close to the first main surface;

[0008] The second external electrode, at least a portion of which is located on the second end face, includes a third region and a fourth region. The third region includes a second conductive layer on the ceramic body and a third welding layer outside the second conductive layer. The second conductive layer is electrically connected to the second internal electrode. The fourth region includes a second vibration buffer layer on the ceramic body and a fourth welding layer outside the second vibration buffer layer. The fourth region is close to the first main surface.

[0009] Preferably, the first conductive layer covers a portion of the second main surface, a portion of the first end surface, a portion of the first side surface, and a portion of the second side surface; the first welding layer covers the first conductive layer; the first vibration buffer layer covers a portion of the first main surface, a portion of the first end surface, a portion of the first side surface, and a portion of the second side surface; and the second welding layer covers the first vibration buffer layer.

[0010] The second conductive layer covers a portion of the second main surface, a portion of the first end surface, a portion of the first side surface, and a portion of the second side surface; the third welding layer covers the second conductive layer; the second vibration buffer layer covers a portion of the first main surface, a portion of the first end surface, a portion of the first side surface, and a portion of the second side surface; and the fourth welding layer covers the second vibration buffer layer.

[0011] Preferably, the first vibration buffer layer is electrically connected to the first conductive layer, and the second vibration buffer layer is electrically connected to the second conductive layer.

[0012] Preferably, the first buffer layer is in direct contact with the first conductive layer, and the second vibration buffer layer is in direct contact with the second conductive layer.

[0013] Preferably, the first vibration buffer layer and the first conductive layer are spaced apart, and the first vibration buffer layer and the first conductive layer are filled with the first welding layer and / or the second welding layer and are electrically connected through the first welding layer and / or the second welding layer.

[0014] The second vibration buffer layer is spaced apart from the second conductive layer, and the third welding layer and / or the fourth welding layer are filled between the second vibration buffer layer and the second conductive layer and are electrically connected through the third welding layer and / or the fourth welding layer.

[0015] Preferably, the ceramic body further includes a protective layer, which covers the first inner electrode or the second inner electrode closest to the first main surface, and the side of the protective layer facing away from the first inner electrode and the second inner electrode forms the first main surface;

[0016] The first vibration buffer layer covers only a portion of the protective layer, and the second vibration buffer layer covers only a portion of the protective layer.

[0017] Preferably, the first vibration buffer layer comprises a conductive material and is electrically connected to a portion of the first inner electrode; the second vibration buffer layer comprises a conductive material and is electrically connected to a portion of the second inner electrode.

[0018] Preferably, the thickness of the first vibration buffer layer is greater than or equal to the thickness of the first conductive layer, and the thickness of the second vibration buffer layer is greater than or equal to the thickness of the second conductive layer;

[0019] The connection between the first welding layer and the second welding layer forms a stepped structure in which the second welding layer protrudes outward from the ceramic body, and the connection between the third welding layer and the fourth welding layer forms a stepped structure in which the fourth welding layer protrudes outward from the ceramic body.

[0020] Preferably, the thickness of the second weld layer is greater than the thickness of the first weld layer, thereby increasing the protrusion of the second weld layer; the thickness of the fourth weld layer is greater than the thickness of the third weld layer, thereby increasing the protrusion of the fourth weld layer.

[0021] Preferably, the thickness of the first vibration buffer layer is less than the thickness of the first conductive layer, and the thickness of the second vibration buffer layer is less than the thickness of the second conductive layer;

[0022] The connection between the first weld layer and the second weld layer forms a stepped structure in which the first weld layer protrudes outward from the ceramic body, and the connection between the third weld layer and the fourth weld layer forms a stepped structure in which the third weld layer protrudes outward from the ceramic body.

[0023] Preferably, the first vibration buffer layer comprises at least one material selected from silver, lead, and conductive resin, and the second vibration buffer layer comprises at least one material selected from silver, lead, and conductive resin.

[0024] The first conductive layer includes a copper layer on the ceramic body and a nickel layer on the copper layer; the second conductive layer includes a copper layer on the ceramic body and a nickel layer on the copper layer; and the first solder layer, the second solder layer, the third solder layer, and the fourth solder layer are tin layers.

[0025] Preferably, the copper layers in the first conductive layer and the second conductive layer are adhered to the ceramic body by sintering, the nickel layers in the first conductive layer and the second conductive layer are plated on the corresponding copper layers by chemical plating or electroplating, and the first vibration buffer layer and the second vibration buffer layer are adhered to the ceramic body by sintering.

[0026] Preferably, the height of the ceramic body in the stacking direction is L1, the height of the second region on the first end face in the stacking direction is L2, the height of the fourth region on the second end face in the stacking direction is L3, the ratio of height L2 to height L1 is greater than or equal to 0.2 and less than or equal to 0.5, and the ratio of height L3 to height L1 is greater than or equal to 0.2 and less than or equal to 0.5.

[0027] Preferably, the ceramic body has a length of L4 in the longitudinal direction, the second region on the first main surface has a length of L5 in the longitudinal direction, the fourth region on the first main surface has a length of L6 in the longitudinal direction, the ratio of length L5 to length L4 is greater than or equal to 0.1 and less than or equal to 0.2, and the ratio of length L6 to length L4 is greater than or equal to 0.1 and less than or equal to 0.2.

[0028] Compared with the prior art, the beneficial effects of the present invention include at least the following:

[0029] The multilayer ceramic capacitor of the present invention is provided with a first vibration buffer layer and a second vibration buffer layer. The first vibration buffer layer and the second vibration buffer layer are directly disposed on the ceramic body. When the ceramic body is subjected to stress, the first vibration buffer layer and the second vibration buffer layer can more effectively reduce the stress damage to the ceramic body and prevent the ceramic body from breaking and becoming unusable. Attached Figure Description

[0030] Figure 1 This is a three-dimensional structural schematic diagram of the multilayer ceramic capacitor of Embodiment 1 of the present invention.

[0031] Figure 2This is a cross-sectional view of the multilayer ceramic capacitor of Embodiment 1 of the present invention.

[0032] Figure 3 This is a three-dimensional structural schematic diagram of the multilayer ceramic capacitor of Embodiment 2 of the present invention.

[0033] Figure 4 This is a cross-sectional view of the multilayer ceramic capacitor of Embodiment 2 of the present invention.

[0034] Figure 5 This is a three-dimensional structural schematic diagram of the multilayer ceramic capacitor of Embodiment 3 of the present invention.

[0035] Figure 6 This is a cross-sectional view of the multilayer ceramic capacitor of Embodiment 3 of the present invention.

[0036] Figure 7 This is a three-dimensional structural schematic diagram of the multilayer ceramic capacitor of Embodiment 4 of the present invention.

[0037] Figure 8 This is a cross-sectional view of the multilayer ceramic capacitor of Embodiment 4 of the present invention.

[0038] Figure 9 This is a three-dimensional structural schematic diagram of the multilayer ceramic capacitor of Embodiment 5 of the present invention.

[0039] Figure 10 This is a cross-sectional view of the multilayer ceramic capacitor of Embodiment 5 of the present invention.

[0040] In the figure: 1. Ceramic body; 10. Dielectric layer; 101. First main surface; 102. Second main surface; 103. First end face; 104. Second end face; 105. First side face; 106. Second side face; 11. First inner electrode; 12. Second inner electrode; 13. Protective layer; 2. First outer electrode; 20. First region; 201. First conductive layer; 202. First welding layer; 21. Second region; 211. First vibration buffer layer; 212. Second welding layer; 3. Second outer electrode; 30. Third region; 301. Second conductive layer; 302. Third welding layer; 31. Fourth region; 311. Second vibration buffer layer; 312. Fourth welding layer. Detailed Implementation

[0041] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided to make the invention more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore repeated descriptions of them will be omitted.

[0042] The terms used to express position and direction in this invention are illustrated with the accompanying drawings, but changes can be made as needed, and all such changes are included within the scope of protection of this invention.

[0043] Example 1

[0044] Reference Figures 1 to 2 The multilayer ceramic capacitor of the present invention includes: a ceramic body 1, a first external electrode 2, and a second external electrode 3.

[0045] The ceramic body 1 has a first main surface 101 and a second main surface 102 opposite to each other in the stacking direction, a first end surface 103 and a second end surface 104 opposite to each other in the length direction, and a first side surface 105 and a second side surface 106 opposite to each other in the width direction. The first main surface 101 serves as the mounting surface for soldering the multilayer ceramic capacitor onto a circuit board. The ceramic body 1 includes a plurality of dielectric layers 10, a plurality of first internal electrodes 11, and a plurality of second internal electrodes 12. The first internal electrodes 11 and the second internal electrodes 12 are alternately stacked and distributed. The first internal electrodes 11 and the second internal electrodes 12 can be formed by printing conductive paste for the internal electrodes onto a ceramic green sheet. The conductive paste contains one or more alloys of nickel (Ni), copper (Cu), palladium (Pd), silver (Ag), gold (Au), platinum (Pt), tin (Sn), tungsten (W), and titanium (Ti). The plurality of dielectric layers 10 are respectively disposed between the first internal electrodes 11 and the second internal electrodes 12. The dielectric layers 10 can isolate the first internal electrodes 11 and the second internal electrodes 12 to achieve electrical separation, thereby forming a capacitor. There are no particular restrictions on the raw materials of dielectric layer 10, as long as sufficient capacitance can be obtained. Barium titanate-based materials, lead composite perovskite-based materials, strontium titanate-based materials, etc. can be used.

[0046] At least a portion of the first external electrode 2 is located on the first end face 103. The first external electrode 2 includes a first region 20 and a second region 21. The first region 20 includes a first conductive layer 201 and a first solder layer 202. The first conductive layer 201 is located on the ceramic body 1, and the first solder layer 202 is located on the first conductive layer 201. The first conductive layer 201 can be directly electrically connected to the first internal electrode 11, or it can be electrically connected to the first internal electrode 11 through a fuse or other components. The first conductive layer 201 can be a single-layer or multi-layer structure, such as a copper layer, a nickel layer, or a metal compound layer. In this embodiment, the first conductive layer 201 includes a copper layer and a nickel layer. The copper layer can be formed on the ceramic body 1 by sintering, and the nickel layer can be formed by electroplating or chemical plating on the copper layer. The first solder layer 202 is a tin layer, which can be formed by electroplating or chemical plating on the nickel layer. The second region 21 is closer to the first main surface 101 than the first region 20. The second region 21 includes a first vibration buffer layer 211 and a second welding layer 212. The first vibration buffer layer 211 can be formed on the ceramic body 1 by sintering, and the second welding layer 212 can be formed by electroplating or chemical plating on the first vibration buffer layer 211. The first vibration buffer layer 211 can be an insulating material or contain conductive materials. In this embodiment, the first vibration buffer layer 211 can contain at least one material selected from silver, lead, and conductive resin. Silver, lead, and conductive resin are all soft materials with good vibration buffering effect. The second welding layer 212 is a tin layer, which facilitates subsequent welding. At the joint position of the first region 20 and the second region 21, the first conductive layer 201 and the first vibration buffer layer 211 are directly connected and electrically connected. The first conductive layer 201 and the first vibration buffer layer 211 can completely cover the first end face 103 to prevent the plating solution from penetrating into the interior of the ceramic body 1 during subsequent electroplating.

[0047] At least a portion of the second external electrode 3 is located on the second end face 104. The second external electrode 3 includes a third region 30 and a fourth region 31. The third region 30 includes a second conductive layer 301 and a third welding layer 302. The second conductive layer 301 is located on the ceramic body 1, and the third welding layer 302 is located on the second conductive layer 301. The second conductive layer 301 can be directly electrically connected to the second internal electrode 12, or it can be electrically connected to the second internal electrode 12 through a fuse or other components. The second conductive layer 301 can be a single layer or a multi-layer structure, such as a copper layer, a nickel layer, or a metal compound layer. In this embodiment, the second conductive layer 301 includes a copper layer and a nickel layer. The copper layer can be formed on the ceramic body 1 by sintering, and the nickel layer can be formed by electroplating or chemical plating on the copper layer. The third welding layer 302 is a tin layer, which can be formed by electroplating or chemical plating on the nickel layer. The fourth region 31 is close to the first main surface 101. The fourth region 31 includes a second vibration buffer layer 311 and a fourth welding layer 312. The second vibration buffer layer 311 can be formed on the ceramic body 1 by sintering, and the fourth welding layer 312 can be formed by electroplating or chemical plating on the second vibration buffer layer 311. The second vibration buffer layer 311 may contain at least one material selected from silver, lead, and conductive resin. Silver, lead, and conductive resin are all soft materials with good vibration buffering effect. The fourth welding layer 312 is a tin layer, which facilitates subsequent soldering. At the junction of the third region 30 and the fourth region 31, the second vibration buffer layer 311 is directly connected to the second conductive layer 301 and achieves electrical connection. The second conductive layer 301 and the second vibration buffer layer 311 can completely cover the second end face 104 to prevent the plating solution from penetrating into the interior of the ceramic body 1 during subsequent electroplating.

[0048] The structure and material of the first external electrode 2 and the second external electrode 3 can be the same. The copper layer can be used to electrically connect with the internal electrode. Nickel has a high melting point and good stability. The nickel layer covers the copper layer and can protect the copper layer. The nickel is placed between the copper layer and the tin layer to prevent the copper layer and the tin layer from forming an alloy state, enhance the thermal adhesion of the copper layer, and improve the soldering heat resistance of the external electrode. The tin layer improves the solderability between the multilayer ceramic capacitor and the circuit board, and can make the multilayer ceramic capacitor better soldered on the circuit board.

[0049] The aforementioned vibration buffer layer can reduce the impact of stress generated by the electrostriction effect of the ceramic body 1 on the multilayer ceramic capacitor and the circuit board, and can also reduce the impact of stress generated when the circuit board deforms on the multilayer ceramic capacitor and the circuit board. The vibration buffer layer is directly bonded to the ceramic body 1. When the ceramic body 1 exhibits an electrostriction effect, the vibration buffer layer can directly absorb the stretching stress of the ceramic body 1, thereby reducing the stress on the ceramic body 1, the external electrode, and the circuit board, and preventing damage to the ceramic body 1, separation of the external electrode from the ceramic body 1, and separation of the external electrode from the circuit board.

[0050] In this invention, the first external electrode 2 includes a first region 20 and a second region 21, and the second external electrode 3 includes a third region 30 and a fourth region 31. By dividing the first external electrode 2 and the second external electrode 3 into two regions, which are relatively independent, the first region 20 and the third region 30 can be used as independent conductive regions, and the second region 21 and the fourth region 31 can be used as independent vibration buffer regions. Therefore, when the first region 20 and the third region 30 adopt a multilayer structure, the layers are not affected by the vibration buffer layer, and the layers have better bonding force and electrical performance, and higher consistency and stability.

[0051] Furthermore, since the second region 21 and the fourth region 31 can serve as independent vibration buffer regions, the second welding layer 212 of the second region 21 and the fourth welding layer 312 of the fourth region 31 can be made of soft metal. When the circuit board is bent or deformed, the vibration buffer layer and the welding layer are both soft metals, which can directly absorb the stress generated by the circuit board, prevent the separation between the external electrode and the circuit board, and reduce the stress on the ceramic body 1, thereby avoiding the cracking of the ceramic body 1 and the separation of the external electrode from the ceramic body 1.

[0052] In a preferred embodiment, the first conductive layer 201 covers a portion of the second main surface 102, a portion of the first end surface 103, a portion of the first side surface 105, and a portion of the second side surface 106; the first welding layer 202 covers the first conductive layer 201; the first vibration buffer layer 211 covers a portion of the first main surface 101, a portion of the first end surface 103, a portion of the first side surface 105, and a portion of the second side surface 106; and the second welding layer 212 covers the first vibration buffer layer 211. The increased contact area between the first conductive layer 201 and the first vibration buffer layer 211 and the ceramic body 1 enhances the bonding force between them, resulting in a more robust connection between the first conductive layer 201 and the first vibration buffer layer 211 and the ceramic body 1.

[0053] The second conductive layer 301 covers a portion of the second main surface 102, a portion of the first end surface 103, a portion of the first side surface 105, and a portion of the second side surface 106. The third welding layer 302 covers the second conductive layer 301. The second vibration buffer layer 311 covers a portion of the first main surface 101, a portion of the first end surface 103, a portion of the first side surface 105, and a portion of the second side surface 106. The fourth welding layer 312 covers the second vibration buffer layer 311. The increased contact area between the second conductive layer 301 and the second vibration buffer layer 311 and the ceramic body 1 enhances the bonding force between them, resulting in a more secure connection.

[0054] As a preferred embodiment, the height of the ceramic body 1 in the stacking direction is L1, the height of the second region 21 on the first end face 103 in the stacking direction is L2, and the height of the fourth region 31 on the second end face 104 in the stacking direction is L3. The ratio of height L2 to height L1 is greater than 0.2 and less than 0.5, and the ratio of height L3 to height L1 is greater than 0.2 and less than 0.5. In this way, stress is not easily concentrated at the two ends of the ceramic body 1, which can effectively prevent damage to the ceramic body 1. The height ratio of the second region 21 in the stacking direction can give the second region 21 a better buffering effect, and the height ratio of the fourth region 31 in the stacking direction can give the fourth region 31 a better buffering effect. When the internal stress is too large, it will cause the second region 21 and the fourth region 31 to crack with the ceramic body 1, but it will not affect the electrical connection between the outer electrode and the inner electrode. At the same time, it will not affect the area of ​​the electrical connection between the first region 20 and the first inner electrode 11, nor will it affect the area of ​​the electrical connection between the third region 30 and the second inner electrode 12, so that the multilayer ceramic capacitor has a large capacitance value.

[0055] The ceramic body 1 has a length of L4 in the longitudinal direction, the second region 21 on the first main surface 101 has a length of L5 in the longitudinal direction, and the fourth region 31 on the first main surface 101 has a length of L6 in the longitudinal direction. The ratio of length L5 to length L4 is greater than or equal to 0.1 and less than or equal to 0.2, and the ratio of length L6 to length L4 is greater than or equal to 0.1 and less than or equal to 0.2. This makes it difficult for stress to concentrate on the first main surface 101 of the ceramic body 1, which can effectively prevent damage to the ceramic body 1. The length ratio of the second region 21 in the longitudinal direction enables the second region 21 to have a better buffering effect, and the length ratio of the fourth region 31 in the longitudinal direction enables the fourth region 31 to have a better buffering effect. When the internal stress is too large, it will cause the second region 21 and the fourth region 31 to crack with the ceramic body 1, but it will not affect the electrical connection between the outer electrode and the inner electrode. At the same time, the area of ​​the first region 20 electrically connected to the first inner electrode 11 does not affect the area of ​​the third region 30 electrically connected to the second inner electrode 12, so that the multilayer ceramic capacitor has a large capacitance value.

[0056] As a preferred embodiment, the thickness of the first vibration buffer layer 211 is less than the thickness of the first conductive layer 201, and the thickness of the second solder layer 212 is less than or equal to the thickness of the first solder layer 202, or the thickness of the second solder layer 212 is equivalent to the thickness of the first solder layer 202. This allows the connection between the first solder layer 202 and the second solder layer 212 to form a stepped structure where the first solder layer 202 protrudes outwards from the ceramic body 1. When the multilayer ceramic capacitor is soldered to the circuit board using solder, the stepped structure of the first external electrode 2 can control the solder's climbing height. The stepped structure on the first external electrode 2 also facilitates the identification of the mounting surface of the multilayer ceramic capacitor, simplifying subsequent soldering.

[0057] The thickness of the second vibration buffer layer 311 is less than the thickness of the second conductive layer 301, and the thickness of the fourth solder layer 312 is less than or equal to the thickness of the third solder layer 302, or the thickness of the fourth solder layer 312 is comparable to the thickness of the third solder layer 302. This allows the connection between the third solder layer 302 and the fourth solder layer 312 to form a stepped structure where the third solder layer 302 protrudes outwards from the ceramic body 1. When the multilayer ceramic capacitor is soldered to the circuit board using solder, the stepped structure of the second external electrode 3 can control the solder's climbing height. The stepped structure on the second external electrode 3 also facilitates the identification of the mounting surface of the multilayer ceramic capacitor, simplifying subsequent soldering.

[0058] Example 2

[0059] Reference Figures 3 to 4 The multilayer ceramic capacitor of the present invention includes: a ceramic body 1, a first external electrode 2, and a second external electrode 3.

[0060] The structure of the ceramic body 1, the first external electrode 2, and the second external electrode 3 in this embodiment is basically the same as that of the ceramic body 1, the first external electrode 2, and the second external electrode 3 in Embodiment 1, with the following differences.

[0061] The first vibration buffer layer 211 and the first conductive layer 201 are spaced apart, meaning that the first vibration buffer layer 211 and the first conductive layer 201 are not directly connected, but are isolated by a filler between them. The filler can be an insulating material or a conductive material. In this embodiment, the filler is a conductive material, which is a soft metal such as tin. The conductive material can be the first welding layer 202, or the second welding layer 212, or the first welding layer 202 and the second welding layer 212. The first vibration buffer layer 211 and the first conductive layer 201 are electrically connected through the first welding layer 202 and / or the second welding layer 212. The spacing between the first vibration buffer layer 211 and the first conductive layer 201 can increase the buffering effect of the first vibration buffer layer 211 and improve the bending and vibration resistance. Specifically, the spacing between the first vibration buffer layer 211 and the first conductive layer 201 allows the filler to further play a secondary buffering role when the first vibration buffer layer 211 absorbs vibration, thus better preventing the first vibration buffer layer 211 from affecting the first conductive layer 201. The filler can effectively play a vibration buffering role and prevent the electrical connection between the first conductive layer 201 and the first inner electrode 11 from failing.

[0062] The second vibration buffer layer 311 and the second conductive layer 301 are spaced apart, meaning that the second vibration buffer layer 311 and the second conductive layer 301 are not directly connected, but are isolated by a filler between them. The filler can be an insulating material or a conductive material. In this embodiment, the filler is a conductive material, which is a soft metal such as tin. The conductive material can be the third welding layer 302, the fourth welding layer 312, or both the third welding layer 302 and the fourth welding layer 312. The second vibration buffer layer 311 and the second conductive layer 301 are electrically connected through the third welding layer 302 and / or the fourth welding layer 312. The spacing between the second vibration buffer layer 311 and the second conductive layer 301 can increase the buffering effect of the first vibration buffer layer 211 and improve the bending and vibration resistance. Specifically, the spacing between the second vibration buffer layer 311 and the second conductive layer 301 allows the filler to further play a secondary buffering role when the second vibration buffer layer 311 absorbs vibration, thus better preventing the second vibration buffer layer 311 from affecting the second conductive layer 301. The filler can effectively play a vibration buffering role and prevent the electrical connection between the second conductive layer 301 and the second inner electrode 12 from failing.

[0063] In this embodiment, the ceramic body 1 further includes a protective layer 13, which covers the first inner electrode 11 or the second inner electrode 12 closest to the first main surface 101. The side of the protective layer 13 facing away from the first inner electrode 11 and the second inner electrode 12 forms the first main surface 101. The thickness of the protective layer 13 can be greater than the thickness of at least one dielectric layer 10, and the material of the protective layer 13 can be the same as that of the dielectric layer 10. Since the first inner electrode 11 or the second inner electrode 12 is not disposed in the protective layer 13, the protective layer 13 will not undergo electrostriction when the multilayer ceramic capacitor is energized, and therefore will not deform. Preferably, the first vibration buffer layer 211 covers only a portion of the protective layer 13, and the second vibration buffer layer 311 covers only a portion of the protective layer 13. In this embodiment, the stepped structure is set at the position of the protective layer 13. When the multilayer ceramic capacitor is soldered onto the circuit board with solder, the solder will have difficulty continuing to climb upwards when it reaches the stepped position due to the limitation of the stepped structure. Therefore, the solder climbing height on the first external electrode 2 is not higher than the thickness of the protective layer 13 in the stacking direction, and the solder climbing height on the second external electrode 3 is not higher than the thickness of the protective layer 13 in the stacking direction. This can not only effectively control the climbing position of the solder, but also reduce the impact on the circuit board when the ceramic body 1 undergoes electrostriction, and also reduce the damage to the ceramic body 1 when the circuit board deforms.

[0064] Example 3

[0065] Reference Figures 5 to 6 The multilayer ceramic capacitor of the present invention includes: a ceramic body 1, a first external electrode 2, and a second external electrode 3.

[0066] The ceramic body 1 in this embodiment has the same or similar structure as the ceramic body 1 in embodiments 1-2, and will not be described in detail here.

[0067] The structure of the first external electrode 2 and the second external electrode 3 in this embodiment is similar to that of the first external electrode 2 and the second external electrode 3 in embodiments 1-2, with the following differences.

[0068] The first vibration buffer layer 211 is taller in the stacking direction and also contains conductive material. The second vibration buffer layer 311 is also taller in the stacking direction and also contains conductive material. The first vibration buffer layer 211 can be electrically connected to a portion of the first inner electrode 11, or the second vibration buffer layer 311 can be electrically connected to a portion of the second inner electrode 12. Of course, the first vibration buffer layer 211 can be electrically connected to a portion of the first inner electrode 11, and the second vibration buffer layer 311 can also be electrically connected to a portion of the second inner electrode 12. The higher the height of the first vibration buffer layer 211 and the second vibration buffer layer 311 in the stacking direction, the better the buffering effect, and the more effectively it can prevent the ceramic body 1 from cracking under stress. Simultaneously, the fact that the first vibration buffer layer 211 can be electrically connected to the first inner electrode 11 and the second vibration buffer layer 311 can be electrically connected to the second inner electrode 12 ensures the capacitive function of the multilayer ceramic body 1 and increases the bonding force between the first vibration buffer layer 211, the second vibration buffer layer 311, and the ceramic body 1.

[0069] Example 4

[0070] Reference Figures 7 to 8 The multilayer ceramic capacitor of the present invention includes: a ceramic body 1, a first external electrode 2, and a second external electrode 3.

[0071] The ceramic body 1 in this embodiment has the same or similar structure as the ceramic body 1 in embodiments 1-3, and will not be described in detail here.

[0072] The structure of the first external electrode 2 and the second external electrode 3 in this embodiment is similar to that of the first external electrode 2 and the second external electrode 3 in embodiments 1-3, with the following differences.

[0073] The thickness of the first vibration buffer layer 211 along the length of the ceramic body 1 is greater than the thickness of the first conductive layer 201. On the one hand, the connection between the first welding layer 202 and the second welding layer 212 can form a stepped structure in which the second welding layer 212 protrudes outward from the ceramic body 1. When the multilayer ceramic capacitor is soldered to the circuit board, the stepped structure of the first external electrode 2 can control the soldering height. On the other hand, the greater thickness of the first vibration buffer layer 211 than the first conductive layer 201 can improve the buffering effect of the first vibration buffer layer 211, and can more effectively release the stress generated by the ceramic body 1 or the stress generated by the deformation of the circuit board. In addition, the bottom width of the multilayer ceramic capacitor in this embodiment is greater than the top width, which can increase the installation stability.

[0074] The thickness of the second vibration buffer layer 311 along the length of the ceramic body 1 is greater than the thickness of the second conductive layer 301. On one hand, the connection between the third welding layer 302 and the fourth welding layer 312 can form a stepped structure in which the fourth welding layer 312 protrudes outward from the ceramic body 1. When the multilayer ceramic capacitor is soldered to the circuit board, the stepped structure of the second external electrode 3 can control the soldering height. On the other hand, the greater thickness of the first and second vibration buffer layers than the thickness of the second conductive layer 301 can improve the buffering effect of the second vibration buffer layer 311, and can more effectively release the stress generated by the ceramic body 1 or the stress generated by the deformation of the circuit board. Furthermore, in this embodiment, the bottom width of the multilayer ceramic capacitor is greater than the top width, which can increase the installation stability.

[0075] Example 5

[0076] Reference Figures 9 to 10 The multilayer ceramic capacitor of the present invention includes: a ceramic body 1, a first external electrode 2, and a second external electrode 3.

[0077] The ceramic body 1 in this embodiment has the same or similar structure as the ceramic body 1 in embodiments 1-4, and will not be described in detail here.

[0078] The structure of the first external electrode 2 and the second external electrode 3 in this embodiment is similar to that in embodiment 4, but the differences are as follows.

[0079] The thickness of the second solder layer 212 along the length of the ceramic body 1 is greater than the thickness of the first solder layer 202. This increases the protrusion of the second solder layer 212, which, when soldering the multilayer ceramic capacitor onto the circuit board, facilitates the accumulation of solder material in the second region 21. Furthermore, the high temperature during soldering causes some nickel and tin layers to form metal compounds, and the solder material has poor wettability on the surface of these metal compounds, affecting the soldering effect. Increasing the thickness of the second solder layer 212 in the second region 21 prevents the metal compounds formed during soldering from reaching the surface of the second region 21, thereby improving the solderability of the second region 21. During soldering, the second solder layer 212 is primarily soldered to the circuit board. Reducing the thickness of the first solder layer 202 does not affect the soldering effect and saves on tin plating material, thus reducing production costs.

[0080] The thickness of the fourth solder layer 312 along the length of the ceramic body 1 is greater than that of the third solder layer 302. This increases the protrusion of the fourth solder layer 312, which, when soldering the multilayer ceramic capacitor onto the circuit board, facilitates the concentration of solder material in the fourth region 31. Furthermore, the high temperature during soldering causes some nickel and tin layers to form metal compounds, and the solder material has poor wettability on the surface of these metal compounds, affecting the soldering effect. Increasing the thickness of the fourth solder layer 312 in the fourth region 31 prevents the metal compounds formed during soldering from reaching the surface of the fourth region 31, thereby improving the solderability of the second region 21. During soldering, the fourth solder layer 312 is primarily soldered to the circuit board. Reducing the thickness of the third solder layer 302 does not affect the soldering effect and saves on tin plating material, thus reducing production costs.

[0081] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the invention without departing from the principles and spirit of the invention, and all such changes should fall within the protection scope of the claims of the present invention.

Claims

1. A multilayer ceramic capacitor, characterized in that, include: The ceramic body has a first main surface and a second main surface opposite to each other in the stacking direction, a first end surface and a second end surface opposite to each other in the length direction, and a first side surface and a second side surface opposite to each other in the width direction. The first main surface is the mounting surface of the multilayer ceramic capacitor. The ceramic body includes a plurality of stacked dielectric layers and alternating stacked first inner electrode and second inner electrode. The dielectric layer is located between the first inner electrode and the second inner electrode. A first external electrode, at least a portion of which is located on the first end face, includes a first region and a second region. The first region includes a first conductive layer on the ceramic body and a first welding layer outside the first conductive layer, the first conductive layer being electrically connected to the first internal electrode. The second region includes a first vibration buffer layer on the ceramic body and a second welding layer outside the first vibration buffer layer, the second region being close to the first main face. The first conductive layer covers a portion of the second main face, a portion of the first end face, a portion of the first side face, and a portion of the second side face. The first welding layer covers the first conductive layer. The first vibration buffer layer covers a portion of the first main face, a portion of the first end face, a portion of the first side face, and a portion of the second side face. The second welding layer covers the first vibration buffer layer. The second external electrode, at least a portion of which is located on the second end face, includes a third region and a fourth region. The third region includes a second conductive layer on the ceramic body and a third welding layer outside the second conductive layer. The second conductive layer is electrically connected to the second internal electrode. The fourth region includes a second vibration buffer layer on the ceramic body and a fourth welding layer outside the second vibration buffer layer. The fourth region is close to the first main surface. The second conductive layer covers a portion of the second main surface, a portion of the second end face, a portion of the first side face, and a portion of the second side face. The third welding layer covers the second conductive layer. The second vibration buffer layer covers a portion of the first main surface, a portion of the second end face, a portion of the first side face, and a portion of the second side face. The fourth welding layer covers the second vibration buffer layer.

2. The multilayer ceramic capacitor according to claim 1, characterized in that, The first vibration buffer layer is electrically connected to the first conductive layer, and the second vibration buffer layer is electrically connected to the second conductive layer.

3. The multilayer ceramic capacitor according to claim 2, characterized in that, The first vibration buffer layer is in direct contact with the first conductive layer, and the second vibration buffer layer is in direct contact with the second conductive layer.

4. The multilayer ceramic capacitor according to claim 2, characterized in that, The first vibration buffer layer and the first conductive layer are spaced apart, and the first vibration buffer layer and the first conductive layer are filled with the first welding layer and / or the second welding layer and are electrically connected through the first welding layer and / or the second welding layer. The second vibration buffer layer is spaced apart from the second conductive layer, and the third welding layer and / or the fourth welding layer are filled between the second vibration buffer layer and the second conductive layer and are electrically connected through the third welding layer and / or the fourth welding layer.

5. The multilayer ceramic capacitor according to claim 1, characterized in that, The ceramic body further includes a protective layer that covers the first inner electrode or the second inner electrode closest to the first main surface, and the side of the protective layer facing away from the first inner electrode and the second inner electrode forms the first main surface. The first vibration buffer layer covers only a portion of the protective layer, and the second vibration buffer layer covers only a portion of the protective layer.

6. The multilayer ceramic capacitor according to claim 1, characterized in that, The first vibration buffer layer contains a conductive material and is electrically connected to a portion of the first inner electrode. The second vibration buffer layer contains a conductive material and is electrically connected to a portion of the second inner electrode.

7. The multilayer ceramic capacitor according to claim 1, characterized in that, The thickness of the first vibration buffer layer is greater than or equal to the thickness of the first conductive layer, and the thickness of the second vibration buffer layer is greater than or equal to the thickness of the second conductive layer; The connection between the first welding layer and the second welding layer forms a stepped structure in which the second welding layer protrudes outward from the ceramic body, and the connection between the third welding layer and the fourth welding layer forms a stepped structure in which the fourth welding layer protrudes outward from the ceramic body.

8. The multilayer ceramic capacitor according to claim 7, characterized in that, The thickness of the second weld layer is greater than the thickness of the first weld layer, and the protrusion of the second weld layer is increased. The thickness of the fourth weld layer is greater than the thickness of the third weld layer, and the protrusion of the fourth weld layer is increased.

9. The multilayer ceramic capacitor according to claim 1, characterized in that, The thickness of the first vibration buffer layer is less than the thickness of the first conductive layer, and the thickness of the second vibration buffer layer is less than the thickness of the second conductive layer; The connection between the first weld layer and the second weld layer forms a stepped structure in which the first weld layer protrudes outward from the ceramic body, and the connection between the third weld layer and the fourth weld layer forms a stepped structure in which the third weld layer protrudes outward from the ceramic body.

10. The multilayer ceramic capacitor according to claim 1, characterized in that, The first vibration buffer layer contains at least one material selected from silver, lead, and conductive resin; the second vibration buffer layer contains at least one material selected from silver, lead, and conductive resin. The first conductive layer includes a copper layer on the ceramic body and a nickel layer on the copper layer; the second conductive layer includes a copper layer on the ceramic body and a nickel layer on the copper layer; and the first solder layer, the second solder layer, the third solder layer, and the fourth solder layer are tin layers.

11. The multilayer ceramic capacitor according to claim 10, characterized in that, The copper layers in the first and second conductive layers are adhered to the ceramic body by sintering, and the nickel layers in the first and second conductive layers are plated on the corresponding copper layers by chemical plating or electroplating. The first vibration buffer layer and the second vibration buffer layer are adhered to the ceramic body by sintering.

12. The multilayer ceramic capacitor according to claim 1, characterized in that, The height of the ceramic body in the stacking direction is L1, the height of the second region on the first end face in the stacking direction is L2, the height of the fourth region on the second end face in the stacking direction is L3, the ratio of height L2 to height L1 is greater than or equal to 0.2 and less than or equal to 0.5, and the ratio of height L3 to height L1 is greater than or equal to 0.2 and less than or equal to 0.

5.

13. The multilayer ceramic capacitor according to claim 1, characterized in that, The ceramic body has a length of L4 in the longitudinal direction, the second region on the first main surface has a length of L5 in the longitudinal direction, and the fourth region on the first main surface has a length of L6 in the longitudinal direction. The ratio of length L5 to length L4 is greater than or equal to 0.1 and less than or equal to 0.2, and the ratio of length L6 to length L4 is greater than or equal to 0.1 and less than or equal to 0.2.

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