JP2018163934A - Feedthrough capacitor - Google Patents

Abstract

Kind Code: A1 A feedthrough capacitor having a desired resistance value and in which an external electrode is difficult to peel off from a base body is provided. A pair of signal external electrodes 3, a ground external electrode 5, a dummy electrode arranged inside the element body 2 and exposed on the side surface 2c, and arranged inside the element body 2. and a signal internal electrode exposed on the pair of end faces 2b, and a ground internal electrode disposed opposite to the signal internal electrode in the element body 2 and exposed on the side surface 2c. , the signal external electrode 3 includes a first sintered electrode layer connected to the signal internal electrode, and the ground external electrode 5 includes a second sintered electrode layer connected to the ground internal electrode. , the dummy electrode is connected to the second sintered electrode layer, the first and second sintered electrode layers contain voids, and the porosity of the first sintered electrode layer is equal to that of the second sintered electrode Greater than the porosity of the layer. [Selection drawing] Fig. 1

Description

  The present invention relates to a feedthrough capacitor.

  An element body having a pair of end faces facing each other and at least one side surface located between the pair of end faces, a pair of signal external electrodes disposed on the pair of end faces, and a pair of signal external electrodes, A ground external electrode that is spaced apart and disposed on the side surface; a signal internal electrode that is disposed in the element body and is exposed to a pair of end surfaces and connected to a corresponding signal external electrode; A feedthrough capacitor is known which includes a ground internal electrode which is disposed in the element body so as to face the signal internal electrode and which is exposed on the side surface and connected to a corresponding ground external electrode (for example, Patent Document 1).

JP 2002-237429 A

  An object of the present invention is to provide a feedthrough capacitor having a desired resistance value and having an external electrode that is hardly peeled off from an element body.

  As a result of research, the present inventors have newly found the following facts.

  Generally, each external electrode of the feedthrough capacitor has a sintered electrode layer and a plating layer that covers the sintered electrode layer. The sintered electrode layer is formed by firing a conductive paste containing metal particles and an organic vehicle. In the firing of the conductive paste, the organic vehicle is gasified and the gas may be accumulated between the conductive paste and the element body without being released to the outside of the feedthrough capacitor. That is, the gas tends to stay between the fired electrode layer and the element body. When the gas stays between the sintered electrode layer and the element body, the bonding area between the external electrode and the element body decreases. In this case, since the external electrode is easily peeled from the element body, the yield decreases.

  By disposing a dummy electrode in the element body and connecting the sintered electrode layer and the dummy electrode, peeling of the external electrode from the element body due to the above factors can be prevented. However, when the dummy electrode and the internal electrode face each other in the height direction, and when the dummy electrode is arranged in the same layer as the internal electrode connected to a different external electrode, the performance of the feedthrough capacitor deteriorates due to stray capacitance etc. There is a risk. Therefore, when a dummy electrode connected to the sintered electrode layer is provided, a contact area between the signal internal electrode and the signal external electrode is limited in order to secure a space in which the dummy electrode is disposed. In this case, since the resistance increases as the contact area between the signal internal electrode and the signal external electrode decreases, it is difficult to obtain a feedthrough capacitor with reduced resistance.

  Therefore, the present inventors have conducted intensive research on a configuration that has a desired resistance value and in which the external electrode is difficult to peel from the element body.

  In firing the conductive paste, the gasified organic vehicle is discharged to the outside through the metal particles, and the metal particles are connected to each other. A part of the gas remains as a void in a portion where the metal particles are not connected to each other. As the metal particles in the electric paste are sparser, the metal particles are less likely to be connected to each other, so that voids made of the gas are easily formed between the metal particles. Therefore, as the metal particles in the conductive paste are sparser, a sintered electrode layer having a larger void ratio (hereinafter referred to as void ratio) is formed. As the metal particles in the conductive paste are denser, the metal particles are more easily connected to each other, so that a sintered electrode layer having a small porosity is formed.

  Focusing on the above points, the present inventors have found that the signal external electrode includes the first sintered electrode layer, the ground external electrode includes the second sintered electrode layer, and the dummy electrode is the second sintered electrode layer. The first sintered electrode layer has a higher porosity than the second sintered electrode layer electrode. In this configuration, since the dummy electrode is connected to the second sintered electrode layer included in the ground external electrode, the ground external electrode is difficult to peel from the element body.

  In the above configuration, since the porosity of the first sintered electrode layer is larger than the porosity of the second sintered electrode layer, the conductivity used in forming the second sintered electrode layer in forming the first sintered electrode layer A conductive paste in which metal particles are sparser than the paste can be used. As the metal particles are sparser, the gas generated during firing is more likely to pass between the metal particles, so that the gas is less likely to stay between the first sintered electrode layer and the element body. Accordingly, since the bonding area between the first sintered electrode layer and the element body can be ensured, the signal external electrode is hardly peeled off from the element body even if the dummy electrode is not connected to the first sintered electrode layer. That is, according to the above configuration, it is possible to provide a feedthrough capacitor having a desired resistance value and each external electrode being difficult to peel from the element body.

  A feedthrough capacitor according to the present invention includes an element body having a pair of end faces facing each other and at least one side surface located between the pair of end faces, and a pair of signal external electrodes disposed on the pair of end faces. A ground external electrode spaced apart from the pair of signal external electrodes and disposed on the side surface; a signal internal electrode disposed in the element body and exposed at the pair of end surfaces; A ground internal electrode that is disposed opposite to the signal internal electrode in the element body and exposed on the side surface, and a dummy electrode that is disposed in the element body and exposed on the side surface, The signal external electrode includes a first sintered electrode layer connected to the signal internal electrode, and the ground external electrode includes a second sintered electrode layer connected to the ground internal electrode and the dummy electrode. Including first The second sintering electrode layer includes a void, the void ratio of the first sintered electrode layer is greater than the porosity of the second sintering electrode layer.

  In the feedthrough capacitor according to the present invention, the dummy electrode is connected to the second sintered electrode layer included in the ground external electrode, and the gap of the first sintered electrode layer included in the signal external electrode The rate is larger than the porosity of the second sintered electrode layer included in the ground external electrode. Therefore, it is possible to provide a feedthrough capacitor having a desired resistance value and in which each external electrode is difficult to peel from the element body.

  The signal external electrode may further include a plating layer disposed on the first sintered electrode layer, and the average thickness of the first sintered electrode layer on the end surface may be 15 μm or more. In the plating process, the plating solution penetrates through the sintered electrode layer and reaches the part where each internal electrode is exposed from the element body, and enters the element body through between each internal electrode and the element body. There is a fear. If the plating solution has entered the element body, cracks are likely to occur in the element body when a feedthrough capacitor is used. Since the plating solution penetrates the sintered electrode layer through the gap, the smaller the porosity of the sintered electrode layer, the more the path through which the plating solution reaches the part where each internal electrode is exposed from the element body is formed. hard. Since the porosity of the second sintered electrode layer is smaller than the porosity of the first sintered electrode layer, the plating solution hardly penetrates the second sintered electrode layer. If the average thickness of the first sintered electrode layer on the end face is 15 μm or more, the plating solution is difficult for the first sintered electrode layer to penetrate. That is, according to the above configuration, cracks are hardly generated in the element body, and the reliability of the element body is improved.

  The element body has a rectangular parallelepiped shape, and further includes a pair of main surfaces facing each other and a side surface facing the at least one side surface, and is exposed at each end surface in a direction orthogonal to the side surface. When the width of the signal internal electrode portion is W1 and the width of the element body is W2, 0.53 ≦ W1 / W2 ≦ 0.83 may be satisfied. In this case, since the contact area between the signal internal electrode and the first sintered electrode layer of the signal external electrode is appropriate, the resistance is reduced while ensuring the reliability of the element body.

  According to the present invention, it is possible to provide a feedthrough capacitor having a desired resistance value and in which an external electrode is hardly peeled from an element body.

1 is a schematic perspective view showing a feedthrough capacitor according to an embodiment. It is a figure for demonstrating the cross-sectional structure of a feedthrough capacitor. It is a figure for demonstrating the cross-sectional structure of a feedthrough capacitor. It is a figure for demonstrating the cross-sectional structure of a feedthrough capacitor. It is a figure for demonstrating the cross-sectional structure of a feedthrough capacitor. It is a figure which shows the mounting state of a penetration capacitor. It is a figure which shows the mounting state of a penetration capacitor. It is a schematic enlarged view of a feedthrough capacitor. It is a schematic enlarged view of a feedthrough capacitor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

  First, the configuration of the feedthrough capacitor 1 according to the present embodiment will be described with reference to FIGS. FIG. 1 is a schematic perspective view showing a feedthrough capacitor according to the present embodiment. 2-5 is a figure for demonstrating the cross-sectional structure of a feedthrough capacitor. In the present embodiment, a feedthrough capacitor 1 will be described as an example of an electronic component. As shown in FIGS. 1 to 5, the feedthrough capacitor 1 includes an element body 2, a pair of signal external electrodes 3 disposed on the outer surface of the element body 2, and a pair of signal external electrodes. A pair of ground external electrodes 5 arranged on the outer surface between the electrodes 3, a plurality of signal internal electrodes 7 arranged inside the element body 2, and signals arranged inside the element body 2 and signals A plurality of ground internal electrodes 9 facing the internal electrode 7 and a dummy electrode 10 disposed inside the element body 2 are provided.

  The element body 2 has a rectangular parallelepiped shape having a pair of main surfaces 2a facing each other, a pair of end surfaces 2b facing each other, and a pair of side surfaces 2c facing each other. The pair of main surfaces 2a oppose each other in the height direction D1. The pair of end faces 2b face each other in the length direction D2. The pair of side surfaces 2c oppose each other in the width direction D3. The length in the length direction D2 and the width direction D3 is larger than the length in the height direction D1, and the length in the length direction D2 is larger than the length in the width direction D3. That is, the area of each main surface 2a is larger than the area of each end surface 2b and the area of each side surface 2c. The area of each side surface 2c is larger than the area of each end surface 2b.

  The rectangular parallelepiped shape includes a rectangular parallelepiped shape in which corners and ridge lines are chamfered and a rectangular parallelepiped shape in which corners and ridge lines are rounded. In the present embodiment, the length of the element body 2 in the height direction D1 is 600 μm, the length in the length direction D2 is 1600 μm, and the length in the width direction D3 is 800 μm.

The element body 2 is configured by laminating a plurality of dielectric layers in the height direction D1 where the pair of main surfaces 2a are opposed to each other. In the element body 2, the stacking direction of the plurality of dielectric layers coincides with the height direction D1. Each dielectric layer is made of a sintered body of a ceramic green sheet containing a dielectric material (dielectric ceramic such as BaTiO ₃ series, Ba (Ti, Zr) O ₃ series, or (Ba, Ca) TiO ₃ series), for example. Composed. In the actual element body 2, the dielectric layers are integrated to such an extent that the boundary between the dielectric layers is not visible.

  As shown in FIG. 1, the pair of signal external electrodes 3 is disposed on each end face 2 b in the length direction D <b> 2 of the element body 2. The pair of signal external electrodes 3 are separated from each other and face each other in the length direction D2. Each signal external electrode 3 includes a pair of conductor portions 3a disposed on the main surface 2a, a conductor portion 3b disposed on the end surface 2b, and a pair of conductor portions 3c disposed on the side surface 2c. And have. In each signal external electrode 3, the conductor portions 3a, 3b, 3c are connected to each other.

  The conductor portion 3b of each signal external electrode 3 covers the entire corresponding end face 2b. In the present embodiment, as shown in FIGS. 1 and 2, the conductor portion 3a and the conductor portion 3c are formed at all ends of the element body 2 from all the end faces 2b in the length direction D2 in a portion having a length of 0.25 mm. Covering the area.

  As shown in FIG. 1, the pair of ground external electrodes 5 are spaced from the pair of signal external electrodes 3 and disposed between the pair of signal external electrodes 3 on the outer surface of the element body 2. ing. The pair of ground external electrodes 5 are arranged at the central portion of the element body 2 in the length direction D2. The pair of ground external electrodes 5 are separated from each other and face each other in the width direction D3. Each ground external electrode 5 has a pair of conductor portions 5a disposed on the main surface 2a and a conductor portion 5b disposed on the side surface 2c. In each ground external electrode 5, the conductor portions 5a and 5b are connected to each other.

  As shown in FIG. 1, the conductor portion 5b of each ground external electrode 5 has a width of a predetermined length in the length direction D2 at the center portion of the side surface 2c in the length direction D2, and has a height. The entire region sandwiched between the pair of main surfaces 2a in the direction D1 is covered. Each conductor portion 5a extends in the width direction D3 from the side surface 2c. In the present embodiment, the length of the conductor portion 5b in the length direction D2 is 0.48 mm, and the length of the conductor portion 5a in the width direction D3 is 0.2 mm.

  The surface roughness of the ground external electrode 5 is larger than the surface roughness of the signal external electrode 3. In the present embodiment, the surface roughness of the ground external electrode 5 is 1500 to 4000 nm in terms of arithmetic average roughness Ra, and the surface roughness of the signal external electrode 3 is 400 to 2000 nm in terms of arithmetic average roughness Ra. .

  FIG. 2 is a cross-sectional view of the feedthrough capacitor 1 taken along a plane that is parallel to the pair of side surfaces 2c and is equidistant from the pair of side surfaces 2c. FIG. 3 is a cross-sectional view of the feedthrough capacitor 1 taken along a plane that is parallel to the pair of end surfaces 2b and is equidistant from the pair of end surfaces 2b. As shown in FIGS. 2 and 3, the signal internal electrode 7 and the ground internal electrode 9 are arranged at different positions (layers) in the height direction of the element body 2. That is, the signal internal electrodes 7 and the ground internal electrodes 9 are alternately arranged in the element body 2 so as to face each other with a gap in the height direction D1.

  In FIG. 4, the feedthrough capacitor 1 is cut along a plane parallel to the pair of main surfaces 2a and equidistant from the pair of main surfaces 2a, and one of the plurality of signal internal electrodes 7 is It is sectional drawing exposed. As shown in FIG. 4, each signal internal electrode 7 has a rectangular shape in which the length direction D2 is the long side direction and the width direction D3 is the short side direction.

  Each signal internal electrode 7 is exposed on the pair of end surfaces 2b, and is not exposed on the pair of main surfaces 2a and the pair of side surfaces 2c. Each signal internal electrode 7 is connected to the corresponding signal external electrode 3 at the end face 2b. In the present embodiment, the width of the signal internal electrode 7 in the width direction D3 is 400 μm or more. That is, the length in the width direction D3 of the part exposed to the end surface 2b in each signal internal electrode 7 is 400 μm or more. In the width direction D3, 0.53 ≦ W1 / W2 ≦ 0.83 is satisfied when the width of the portion where the signal internal electrode 7 is exposed at each end face 2b is W1 and the width of the element body 2 is W2. It is preferred that More preferably, 0.68 ≦ W1 / W2 ≦ 0.83 is satisfied.

  FIG. 5 shows a case where the feedthrough capacitor 1 is cut along a plane that is parallel to the pair of main surfaces 2a and is equidistant from the pair of main surfaces 2a. It is sectional drawing exposed. As shown in FIG. 5, each ground internal electrode 9 faces the signal internal electrode 7 through a part (dielectric layer) of the element body 2 in the height direction D1. Each ground internal electrode 9 has a main electrode portion 9a having a rectangular shape in which the length direction D2 is the long side direction and the width direction D3 is the short side direction, and extends from the long side of the main electrode portion. And a pair of connecting portions 9b exposed on the side surface 2c. The main electrode portion 9a and each connection portion 9b are integrally formed.

  Each ground internal electrode 9 is exposed on the pair of side surfaces 2c and is not exposed on the pair of main surfaces 2a and the pair of end surfaces 2b. Each ground internal electrode 9 is connected to the corresponding ground external electrode 5 on the side surface 2c. In the present embodiment, the minimum width in the length direction D2 of the ground internal electrode 9 is smaller than the minimum width in the width direction D3 of the signal internal electrode 7, and is 50 μm or more. The length in the length direction D2 of the connection portion 9b exposed at the side surface 2c is the minimum width in the length direction D2 of the ground internal electrode 9. The width of the portion where the ground internal electrode 9 (connection portion 9b) is exposed on the side surface 2c is smaller than the width of the portion where each signal internal electrode 7 is exposed on the end surface 2b. That is, the contact area between the signal external electrode 3 and each signal internal electrode 7 is larger than the contact area between the ground external electrode 5 and each ground internal electrode 9.

  As shown in FIG. 5, a plurality of dummy electrodes 10 having a rectangular shape are arranged in the same layer as the ground internal electrode 9. The dummy electrode 10 is separated from the ground internal electrode 9 and the signal internal electrode 7, and is disposed adjacent to the connection portion 9b in the length direction D2 so as to sandwich the connection portion 9b. Each dummy electrode 10 is exposed to the side surface 2 c and connected to the ground external electrode 5. In this embodiment, the length in the length direction D2 of the part exposed to the side surface 2c among each dummy electrode 10 is 50-130 micrometers.

  Each dummy electrode 10 does not face the signal internal electrode 7 in the height direction D1. Four dummy electrodes 10 are arranged in each layer in which all the ground internal electrodes 9 are arranged, and are not arranged in the layer in which the signal internal electrodes 7 are arranged. The electrostatic capacitance component formed between the signal internal electrode 7 and the dummy electrode 10 is extremely different from the electrostatic capacitance component formed between the signal internal electrode 7 and the ground internal electrode 9. It is small and does not substantially contribute to the capacitance component formed by the feedthrough capacitor 1.

  The signal internal electrode 7, the ground internal electrode 9, and the dummy electrode 10 are made of a conductive material (for example, Ni or Cu) that is usually used as an internal electrode of a laminated electric element. The signal internal electrode 7 and the ground internal electrode 9 are configured as a sintered body of a conductive paste containing the conductive material.

  The feedthrough capacitor 1 is solder mounted on an electronic device (for example, a circuit board or other electronic component) 20 as shown in FIGS. FIG. 6 is a cross-sectional view of the feedthrough capacitor 1 mounted on the electronic device 20 taken along a plane parallel to the pair of side surfaces 2c and equidistant from the pair of side surfaces 2c. FIG. 7 is a cross-sectional view of the feedthrough capacitor 1 mounted on the electronic device 20 on a plane that is parallel to the pair of end surfaces 2b and is equidistant from the pair of end surfaces 2b.

  One of the pair of main surfaces 2 a is a mounting surface facing the electronic device 20. A solder fillet 22 is formed between each signal external electrode 3 and a pad electrode (not shown) of the electronic device 20. A solder fillet 23 is formed between each ground external electrode 5 and the pad electrode of the electronic device 20. The length of the solder fillet 23 in the height direction D1 is smaller than the length of the solder fillet 22 in the height direction D1. The length of the solder fillet 23 in the width direction D3 is smaller than the length of the solder fillet 22 in the length direction D2.

  Next, detailed configurations of the signal external electrode 3 and the ground external electrode 5 will be described with reference to FIGS. FIG. 8 is an enlarged view of the signal external electrode 3 in the feedthrough capacitor 1 shown in FIG. FIG. 9 is an enlarged view of the ground external electrode 5 in the feedthrough capacitor 1 shown in FIG.

  As shown in FIG. 8, each signal external electrode 3 includes a first sintered electrode layer 31, a first plated layer 32, and a second plated layer 33. The first sintered electrode layer 31 covers a portion where the signal internal electrode 7 is exposed at the pair of end faces 2 b and is connected to the signal internal electrode 7. In the present embodiment, the first sintered electrode layer 31 is in contact with the entire end surface 2b. In the present embodiment, the edge of the region where the first sintered electrode layer 31 is in contact with the end face 2b is separated by 30 μm or more from the portion where the signal internal electrode 7 is exposed on the end face 2b. The average thickness of the first sintered electrode layer 31 on the end face 2b is 15 to 50 μm.

  The first plating layer 32 is formed on the first sintered electrode layer 31 by plating (for example, electroplating). That is, the first sintered electrode layer 31 is plated so that the entire outer surface is covered with the first plating layer 32. The second plating layer 33 is formed on the first plating layer 32 by plating. That is, the first plating layer 32 is plated so that the entire outer surface is covered with the second plating layer 33. Each of the conductor portions 3a, 3b, 3c includes a first sintered electrode layer 31, a first plating layer 32, and a second plating layer 33.

  As shown in FIG. 9, each ground external electrode 5 includes a second sintered electrode layer 51, a third plating layer 52, and a fourth plating layer 53. The second sintered electrode layer 51 covers a portion where the ground internal electrode 9 (connecting portion 9b) is exposed on the pair of side surfaces 2c and is connected to the ground internal electrode 9 (connecting portion 9b) and the dummy electrode 10. Has been. In the present embodiment, the edge of the region where the second sintered electrode layer 51 is in contact with the side surface 2c is 30 μm or more from the portion where the ground internal electrode 9 (connection portion 9b) and the dummy electrode 10 are exposed on the side surface 2c. is seperated. The average thickness of the second sintered electrode layer 51 on the side surface 2c is 5 to 20 μm. The contact area between the first sintered electrode layer 31 and each signal internal electrode 7 is larger than the contact area between the second sintered electrode layer 51 and each ground internal electrode 9.

  The third plating layer 52 is formed on the second sintered electrode layer 51 by plating. That is, the second sintered electrode layer 51 is plated so that the entire outer surface thereof is covered with the third plating layer 52. The fourth plating layer 53 is formed on the third plating layer 52 by plating. That is, the third plating layer 52 is plated so that the entire outer surface thereof is covered with the fourth plating layer 53. Each of the conductor portions 5 a and 5 b includes a second sintered electrode layer 51, a third plating layer 52, and a fourth plating layer 53.

  The first sintered electrode layer 31 and the second sintered electrode layer 51 are formed by baking with a conductive paste applied to the surface of the element body 2. Each of the sintered electrode layers 31 and 51 is a sintered metal layer formed by sintering a metal component (metal powder) contained in the conductive paste. In the present embodiment, the sintered electrode layers 31 and 51 are sintered metal layers made of Cu. The sintered electrode layers 31 and 51 may be sintered metal layers made of Ni. As the conductive paste, a powder made of metal (for example, Cu or Ni) mixed with a glass component, an organic binder, and an organic solvent is used.

  In the present embodiment, the first and third plating layers 32 and 52 are Ni plating layers formed by Ni plating. The first and third plating layers 32 and 52 may be Sn plating layers, Cu plating layers, or Au plating layers. The second and fourth plating layers 33 and 53 are Sn plating layers formed by Sn plating. The second and fourth plating layers 33 and 53 may be Cu plating layers or Au plating layers.

  As shown in FIGS. 8 and 9, the first sintered electrode layer 31 of the signal external electrode 3 and the second sintered electrode layer 51 of the ground external electrode 5 are included in the conductive paste. The void 30 is formed of the volatile component gas or the like. In the present embodiment, a space having a maximum diameter of 10 μm or less is defined as the gap 30. 8 and 9, the air gap 30 is schematically shown as an ellipse. The actual shape of the gap 30 is not limited to an ellipse (ellipsoid).

  The porosity of the first sintered electrode layer 31 is larger than the porosity of the second sintered electrode layer 51. In the present embodiment, the porosity of the first sintered electrode layer 31 is 0.2 to 1.0%, and the porosity of the second sintered electrode layer 51 is 0.02 to 0.18%. The porosity of the 1st sintered electrode layer 31 and the 2nd sintered electrode layer 51 can be calculated | required as follows, for example.

  About each of the 1st sintered electrode layer 31 and the 2nd sintered electrode layer 51, a cross-sectional photograph is acquired with a scanning electron microscope. For example, the cross sections of the first sintered electrode layer 31 and the second sintered electrode layer 51 when cut along a plane parallel to the pair of main surfaces 2a and equidistant from the pair of main surfaces 2a. A photograph is used. On the acquired cross-sectional photograph, each area of the gap 30 in each sample region is calculated for each of the first sintered electrode layer 31 and the second sintered electrode layer 51.

  For example, in the first sintered electrode layer 31, a sample region is defined as +5 μm in the length direction D2 from the end surface 2b and ± 125 μm in the width direction D3 from the center line of the end surface 2b in the cross-sectional photograph. In the second sintered electrode layer 51, an area of +5 μm in the width direction D3 from the side surface 2c and ± 125 μm in the length direction D2 from the center line of the side surface 2c in the cross-sectional photograph is used as a sample region.

  The area of the void 30 in the first sintered electrode layer 31 is divided by the area of the sample region of the first sintered electrode layer 31, and the value obtained by expressing the obtained quotient as a percentage is the void in the first sintered electrode layer 31. Rate. The area of the void 30 in the second sintered electrode layer 51 is divided by the area of the sample region of the second sintered electrode layer 51, and the value obtained by expressing the obtained quotient in percentage is the void in the second sintered electrode layer 51. Rate.

  As described above, since the dummy electrode 10 is connected to the second sintered electrode layer 51 included in the ground external electrode 5, the ground external electrode 5 is difficult to peel from the element body 2. Since the porosity of the first sintered electrode layer 31 is larger than the porosity of the second sintered electrode layer 51, the conductivity used in forming the second sintered electrode layer 51 in forming the first sintered electrode layer 31. A conductive paste in which metal particles are sparser than the paste can be used. As the metal particles are sparser, the gas generated during firing is more likely to pass between the metal particles, so that the gas is less likely to stay between the first sintered electrode layer 31 and the element body 2. Accordingly, since the bonding area between the first sintered electrode layer 31 and the element body 2 can be ensured, the signal external electrode 3 can be connected to the first sintered electrode layer 31 from the element body 2 even if the dummy electrode 10 is not connected. Hard to peel. Therefore, the feedthrough capacitor 1 has a desired resistance value, and the external electrodes 3 and 5 are hardly separated from the element body.

  In the plating process, the plating solution penetrates the first and second sintered electrode layers 31 and 51 to reach the portion where the internal electrodes 7 and 9 are exposed from the element body 2, and the internal electrodes 7 and 9. There is a risk of entering between the element body 2 and the element body 2. If the plating solution enters the element body 2, cracks are likely to occur in the element body 2 when the feedthrough capacitor 1 is used. Since the plating solution penetrates the sintered electrode layer through the gap, the smaller the porosity of each of the sintered electrode layers 31, 51, the more the inner electrodes 7, 9 are plated on the portions exposed from the element body 2. A path through which the liquid reaches is difficult to form.

  Since the porosity of the second sintered electrode layer 51 is smaller than the porosity of the first sintered electrode layer 31, it is difficult for the plating solution to penetrate the second sintered electrode layer 51. If the average thickness of the first sintered electrode layer 31 on the end surface 2b is 15 μm or more, the plating solution is difficult for the first sintered electrode layer 31 to penetrate. That is, according to the above configuration, cracks are unlikely to occur in the element body 2 and the reliability of the element body 2 is improved.

  In the direction orthogonal to the pair of side surfaces 2c (width direction D3), when the width of the portion where the signal internal electrode 7 is exposed at each end face 2b is W1 and the width of the element body is W2, 0.53 ≦ W1 / W2 ≦ 0.83 is satisfied. In this case, since the contact area between the signal internal electrode 7 and the first sintered electrode layer 31 is appropriate, the resistance is reduced while ensuring the reliability of the element body 2. More preferably, 0.68 ≦ W1 / W2 ≦ 0.83 is satisfied, and the resistance is further reduced while the reliability of the element body 2 is ensured.

  The width of the portion where the ground internal electrode 9 is exposed on the side surface 2c is smaller than the width of the portion where each signal internal electrode 7 is exposed on the end surface 2b. If the width of the portion where the internal electrode is exposed from the element body 2 is reduced, the path for the plating solution to enter can be narrowed, so that the penetration of the plating solution into the element body 2 is suppressed. For this reason, the width of the portion where the ground internal electrode 9 is exposed from the element body 2 is reduced while the increase in resistance is suppressed by securing the contact area between the signal internal electrode 7 and the signal external electrode 3. As a result, the generation of cracks due to the penetration of the plating solution is further suppressed.

  The area of each main surface 2a is larger than the area of each side surface 2c and the area of each end surface 2b, the area of each side surface 2c is larger than the area of each end surface 2b, and the surface roughness of the ground external electrode 5 is It is larger than the surface roughness of the signal external electrode 3. If the area of each side surface 2c is larger than the area of each end surface 2b, when the feedthrough capacitor 1 is solder-mounted on the electronic device 20 in each of the external electrodes 3 and 5, the electronic device 20 and the ground external electrode 5 The force per unit area acting on the joint portion tends to be larger than the force per unit area acting on the joint portion between the electronic device 20 and the signal external electrode 3.

  If the surface roughness of the ground external electrode 5 is greater than the surface roughness of the signal external electrode 3, the bonding strength between the ground external electrode 5 and the solder is greater than the bonding strength between the signal external electrode 3 and the solder. The feedthrough capacitor 1 is difficult to peel off from the electronic device 20. Since the surface roughness of the ground external electrode 5 is larger than the surface roughness of the signal external electrode 3, solder hardly rises in the ground external electrode 5. Therefore, since the size of the solder fillet 23 in the ground external electrode 5 is reduced, the density of the feedthrough capacitor 1 mounted on the electronic device 20 in the width direction D3 can be improved.

  As mentioned above, although embodiment of this invention has been described, this invention is not necessarily limited to embodiment mentioned above, A various change is possible in the range which does not deviate from the summary.

  For example, in this embodiment, each signal external electrode 3 has conductor portions 3a and 3c on a pair of main surfaces 2a and a pair of side surfaces 2c, but each signal external electrode 3 is on each end surface 2b. Only the conductor portion 3b may be provided. Similarly, in this embodiment, each ground external electrode 5 has a conductor portion 5a on a pair of main surfaces 2a. However, each ground external electrode 5 has a conductor portion 5b only on each side surface 2c. You may have.

  One or three or more ground external electrodes 5 may be disposed on the side surface 2c located between the pair of end surfaces 2b. The ground external electrode 5 may be disposed on at least one surface of the pair of side surfaces 2c.

  The shape of the element body 2 is not limited to a rectangular parallelepiped shape as long as it has at least one side face located between a pair of end faces facing each other and the pair of end faces.

  In the present embodiment, each signal internal electrode 7 has a rectangular shape, but is not limited thereto. For example, each signal internal electrode 7 may include a main electrode portion having a rectangular shape and a pair of connection portions extending from the main electrode portion and exposed at each end face 2b. Good. In this case, the minimum width in the width direction D3 of the signal internal electrode 7 is 400 μm or more, and the length in the width direction D3 of the portion of the connecting portion exposed at the end face 2b is the width of the signal internal electrode 7. This is the minimum width in the direction D3.

  DESCRIPTION OF SYMBOLS 1 ... Feed-through capacitor, 2 ... Element body, 2a ... Main surface, 2b ... End surface, 2c ... Side surface, 3 ... Signal external electrode, 5 ... Ground external electrode, 7 ... Signal internal electrode, 9 ... Ground internal electrode DESCRIPTION OF SYMBOLS 10 ... Dummy electrode, 30 ... Space | gap, 31 ... 1st sintered electrode layer, 51 ... 2nd sintered electrode layer, 32, 33, 52, 53 ... Plating layer, D1 ... Height direction, D2 ... Length direction , D3... Width direction.

Claims (3)

An element body having a pair of end faces facing each other and at least one side face located between the pair of end faces;
A pair of signal external electrodes disposed on the pair of end faces;
A ground external electrode spaced apart from the pair of signal external electrodes and disposed on the side surface;
An internal electrode for a signal that is disposed in the element body and exposed at the pair of end faces;
The ground internal electrode that is disposed in the element body so as to face the signal internal electrode and is exposed on the side surface,
A dummy electrode disposed in the element body and exposed on the side surface,
The signal external electrode includes a first sintered electrode layer connected to the signal internal electrode,
The ground external electrode includes a second sintered electrode layer connected to the ground internal electrode and the dummy electrode,
The first and second sintered electrode layers include voids,
The porosity of said 1st sintered electrode layer is a feedthrough capacitor larger than the porosity of said 2nd sintered electrode layer. The signal external electrode further includes a plating layer disposed on the first sintered electrode layer,
2. The feedthrough capacitor according to claim 1, wherein an average thickness of the first sintered electrode layer on the end face is 15 μm or more. The element body has a rectangular parallelepiped shape, and further includes a pair of main surfaces facing each other, and a side surface facing the at least one side surface,
In the direction orthogonal to the side surface, when the width of the portion of the signal internal electrode exposed at each end face is W1, and the width of the element body is W2,
0.53 ≦ W1 / W2 ≦ 0.83
The feedthrough capacitor according to claim 1 or 2, wherein:

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