JP2018198326A - Multilayer capacitor - Google Patents

Abstract

To provide a multilayer capacitor enabling the breakdown voltage failure thereof to be prevented.SOLUTION: The multilayer capacitor comprises a laminate, an external electrode, and a plurality of dummy electrodes. The laminate includes: internal electrodes and dielectric layers alternately laminated in a first direction; protective layers disposed on both sides in the first direction; a first surface directed toward the first direction; a second surface directed toward a second direction orthogonal to the first direction; a third surface directed toward a third direction orthogonal to the first and second directions; and a ridge connecting the first surface and the second surface to each other. The external electrode covers the second surface and is connected to the internal electrodes. The plurality of dummy electrodes is exposed on the second and third surfaces. The plurality of dummy electrodes include a plurality of second dummy electrodes that are disposed in the protective layer and are exposed on the second surface where the end portions of the internal electrodes adjacent to the protective layer are not exposed. All the plurality of second dummy electrodes are arranged between the end portion and the ridge portion closest to the end portion.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a multilayer capacitor capable of preventing a breakdown voltage failure and a method for manufacturing the same.

  The multilayer capacitor includes a multilayer body in which a first internal electrode, a dielectric layer, and a second internal electrode are stacked, and first and second external electrodes provided on both end faces of the multilayer body, respectively. The first external electrode is connected to the first internal electrode, and the second external electrode is connected to the second internal electrode. End margin portions for insulating the first external electrode and the second internal electrode and insulating the second external electrode and the first internal electrode are provided on both end faces of the multilayer body.

  In the manufacturing process of the multilayer capacitor, barrel polishing is performed on the multilayer body before the first and second external electrodes are provided for the purpose of surface smoothing, deburring, chamfering, and the like (for example, Patent Document 1). reference). Barrel polishing improves the adhesion of the first and second external electrodes to the multilayer body, and can prevent the top of the multilayer body from being chipped during the production process of the multilayer capacitor.

JP 2010-205812 A

  Since the laminated body of the multilayer capacitor is composed of ceramics which are brittle materials, it is easily worn by barrel polishing. If the laminate is worn too much by barrel polishing, the end margins on both end faces of the laminate are narrowed, and between the first external electrode and the second internal electrode and between the second external electrode and the first internal electrode. May have insufficient pressure resistance.

  In view of the circumstances as described above, an object of the present invention is to provide a multilayer capacitor capable of preventing a breakdown voltage failure and a method for manufacturing the same.

In order to achieve the above object, a multilayer capacitor according to an embodiment of the present invention includes a multilayer body, an external electrode, a first dummy electrode, and a second dummy electrode.
The laminated body has internal electrodes and dielectric layers alternately laminated and has a protective layer.
The external electrode covers the end surface of the laminate and is connected to the internal electrode.
The first dummy electrode is provided on a side surface side of the internal electrode, and is exposed on an end surface and a side surface of the stacked body.
The second dummy electrode is provided on the protective layer and exposed on an end surface and a side surface of the stacked body.

  In this configuration, the first and second dummy electrodes are provided on the outer peripheral portions of both end faces of the multilayer body. Since the first and second dummy electrodes made of a metal material have high strength and the density is high, the outer peripheral portions of both end faces of the laminate are not easily worn by barrel polishing. That is, in this multilayer capacitor, the first and second dummy electrodes can prevent the outer peripheral portions of both end faces of the multilayer body from being excessively worn by barrel polishing. Thereby, in this multilayer capacitor, insulation between the external electrode and the internal electrode is ensured, so that a withstand voltage failure is less likely to occur.

The second dummy electrode may be continuous from one side surface to the other side surface of the laminate.
In this configuration, it is possible to prevent the protective layer from being excessively worn by barrel polishing, and thus it is possible to suppress a decrease in pressure resistance between the external electrode and the uppermost and lowermost internal electrodes.

A plurality of the second dummy electrodes may be present in the protective layer.
In this configuration, it is possible to effectively prevent the protective layer from being excessively worn by barrel polishing, so that it is possible to effectively suppress a decrease in pressure resistance between the external electrode and the uppermost and lowermost internal electrodes.

A distance between the internal electrode and the first dummy electrode separated from the internal electrode may be larger than a thickness of the dielectric layer.
In this configuration, since the distance between the internal electrode and the first dummy electrode that is separated from the internal electrode can be maintained even after barrel polishing, it is possible to suppress a decrease in the pressure resistance of the multilayer capacitor.

The internal electrode, the first dummy electrode, and the second dummy electrode may be formed of the same metal material.
In this configuration, the first and second internal electrodes and the first and second dummy electrodes exhibit the same sintering behavior when the multilayer capacitor is fired. This makes it difficult for cracks to occur in the multilayer capacitor.

In the method for manufacturing a multilayer capacitor according to one aspect of the present invention, a ceramic sheet is prepared.
An internal electrode and a first dummy electrode are formed on the ceramic sheet to produce a first sheet.
A second dummy electrode is formed on the ceramic sheet to produce a second sheet.
The ceramic sheet, the first sheet, and the second sheet are laminated to produce a laminate.
The laminate is cut.
Barrel polishing is performed on the cut laminate.
The laminate subjected to the barrel polishing is fired.

  A multilayer capacitor capable of preventing a breakdown voltage failure and a manufacturing method thereof can be provided.

1 is a perspective view of a multilayer capacitor according to an embodiment of the present invention. It is a perspective view of the laminated body of the said multilayer capacitor. It is sectional drawing along the AA 'line of FIG. 1 of the said multilayer capacitor. It is sectional drawing along the BB 'line of FIG. 1 of the said multilayer capacitor. It is sectional drawing along CC 'line of FIG. 1 of the said multilayer capacitor. It is sectional drawing along the DD 'line of FIG. 1 of the said multilayer capacitor. It is a top view of the electrode layer of the said multilayer capacitor. It is a top view of the electrode layer which concerns on the modification of the said multilayer capacitor. It is a top view of the electrode layer which concerns on the modification of the said multilayer capacitor. It is a top view of the protective layer of the said multilayer capacitor. It is a flowchart which shows the manufacturing method of the said multilayer capacitor. It is a top view of the 1st sheet in the manufacture process of the above-mentioned multilayer capacitor. It is a top view of the 2nd sheet in the manufacture process of the above-mentioned multilayer capacitor. It is a top view of the 3rd sheet in the manufacture process of the above-mentioned multilayer capacitor. It is a perspective view which shows the lamination | stacking in the manufacture process of the said multilayer capacitor. It is a perspective view of the unbaked laminated body in the manufacture process of the said multilayer capacitor. It is a perspective view of the laminated body after barrel polishing in the manufacturing process of the multilayer capacitor. It is a perspective view of the multilayer capacitor in which the paste-like external electrode was formed in the manufacturing process of the multilayer capacitor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the drawing, an X axis, a Y axis, and a Z axis that are orthogonal to each other are shown as appropriate. The X axis, Y axis, and Z axis are common in all drawings.

[Configuration of Multilayer Capacitor 10]
FIG. 1 is a perspective view of the multilayer capacitor 10 according to the first embodiment of the present invention. The multilayer capacitor 10 includes a multilayer body 11, a first external electrode 14, and a second external electrode 15. The external electrodes 14 and 15 are provided at both ends of the stacked body 11 in the X-axis direction.

  FIG. 2 is a perspective view of the laminate 11. The stacked body 11 has a first end face T1 and a second end face T2 perpendicular to the X axis. The first external electrode 14 is provided on the first end face T1, and the second external electrode 15 is provided on the second end face T2. The stacked body 11 has a first side surface S1 and a second side surface S2 perpendicular to the Y axis.

  The stacked body 11 includes an electrode layer 16, a first protective layer 17, and a second protective layer 18. The electrode layer 16 has a rectangular parallelepiped shape having sides along the X axis, the Y axis, and the Z axis. The protective layers 17 and 18 each have a flat plate shape extending along the XY plane. The first protective layer 17 is provided on the upper surface of the electrode layer 16 in the Z-axis direction, and the second protective layer 18 is provided on the lower surface of the electrode layer 16 in the Z-axis direction.

  The laminated body 11 has a substantially rectangular parallelepiped shape having sides along the X axis, the Y axis, and the Z axis as a whole of the electrode layer 16 and the protective layers 17 and 18. The laminated body 11 before the external electrodes 14 and 15 are subjected to barrel polishing for the purpose of smoothing the surface, deburring, and chamfering. Due to the barrel polishing, in particular, the eight top portions P of the laminated body 11 are worn to form gentle curved surfaces.

  3 is a cross-sectional view of the multilayer capacitor 10 taken along the line AA ′ of FIG. 1, and FIG. 4 is a cross-sectional view of the multilayer capacitor 10 taken along the line BB ′ of FIG. 5 is a cross-sectional view of the multilayer capacitor 10 taken along the line CC ′ of FIG. 1, and FIG. 6 is a cross-sectional view of the multilayer capacitor 10 taken along the line DD ′ of FIG.

  3 and 4 show cross sections of the multilayer capacitor 10 parallel to the ZX plane. 3 shows the center portion of the multilayer capacitor 10 in the Y-axis direction, and FIG. 4 shows the end portion of the multilayer capacitor 10 in the Y-axis direction. 5 and 6 show a cross section of the multilayer capacitor 10 parallel to the YZ plane. FIG. 5 shows the center portion of the multilayer capacitor 10 in the X-axis direction, and FIG. 6 shows the end portion of the multilayer capacitor 10 in the X-axis direction.

  The electrode layer 16 has a plurality of first internal electrodes 12 and a plurality of second internal electrodes 13. Each of the internal electrodes 12 and 13 has a sheet shape extending along the XY plane, and is alternately stacked in the Z-axis direction. The first internal electrode 12 is exposed at the first end face T <b> 1 and is connected to the first external electrode 14. The second internal electrode 13 is exposed at the second end face T <b> 2 and is connected to the second external electrode 15.

  The electrode layer 16 has an end margin portion 24 and a side margin portion 25. The end margin portion 24 is provided on each of the end surfaces T1 and T2 of the electrode layer 16, and the side margin portion 25 is provided on each of the side surfaces S1 and S2 of the electrode layer 16.

  The end margin portion 24 forms a margin between the first end face T1 and the second internal electrode 13 and between the second end face T2 and the first internal electrode 12, and the first external electrode 14 and the second internal electrode 13, and the second external electrode 15 and the first internal electrode 12 are insulated. The side margin portion 25 forms a margin between the side surfaces S1, S2 and the internal electrodes 12, 13, and ensures the pressure resistance at the side surfaces S1, S2.

  The protective layers 17 and 18 cover the internal electrodes 12 and 13 on the upper and lower surfaces in the Z-axis direction of the electrode layer 16, and rotate from the end surfaces T1 and T2 of the stacked body 11 to the upper and lower surfaces in the Z-axis direction. Insulating the external electrodes 14 and 15 embedded therein. Accordingly, the first external electrode 14 is insulated from the second internal electrode 13 by the end margin portion 24 and the protective layers 17 and 18, and the second external electrode 15 is insulated from the first internal electrode 12 by the end margin portion 24 and the protective layers 17 and 18. Insulated from.

  The multilayer body 11 (electrode layer 16 and protective layers 17 and 18) of the multilayer capacitor 10 is made of dielectric ceramics. In the multilayer capacitor 10, a material having a high dielectric constant is employed as the ceramic constituting the multilayer body 11 in order to increase the capacitance of each dielectric layer between the first internal electrode 12 and the second internal electrode 13.

As the ceramic constituting the laminated body 11, for example, a material having a perovskite structure including barium (Ba) and titanium (Ti) represented by barium titanate (BaTiO ₃ ) can be used.

  With the above configuration, in the multilayer capacitor 10, when a voltage is applied between the first external electrode 14 and the second external electrode 15, a plurality of dielectrics between the first internal electrode 12 and the second internal electrode 13 are obtained. Voltage is applied to the body layer.

  The withstand voltage of the multilayer capacitor 10 is desirably 25 V or more, and more desirably 50 V or more. In order to obtain high breakdown voltage in the multilayer capacitor 10, the thickness of the dielectric layer in the electrode layer 16 is increased. When the thickness of the dielectric layer is increased, the ratio of the internal electrodes 12 and 13 between the layers of the multilayer capacitor 10 is decreased. The thickness of the dielectric layer is desirably 6 μm or more, and more desirably 9 μm or more.

  In the manufacturing process of the multilayer capacitor 10, barrel polishing is performed on the unsintered multilayer body 11. The present inventor has found that when the corners (tops and ridges) of the multilayer body 11 are excessively worn by barrel polishing and the distance between the external electrodes 14 and 15 and the internal electrodes 12 and 13 becomes too close, the multilayer capacitor It has been found that the pressure resistance of 10 decreases.

  For this reason, in the multilayer capacitor 10 according to this embodiment, by arranging the dummy electrodes 20 and 21 in the multilayer body 11, the density of the corners of the multilayer body 11 is increased, and the corners of the multilayer body 11 are excessively worn. To prevent. Furthermore, since the dummy electrodes 20 and 21 are formed of a metal material, wear of the corners of the multilayer body 11 is more effectively suppressed.

  FIG. 7A is a plan view of the electrode layer 16, and FIG. 8 is a plan view of the protective layers 17 and 18. The multilayer body 11 of the multilayer capacitor 10 includes a first dummy electrode 20 and a second dummy electrode 21. The first dummy electrode 20 is provided on the electrode layer 16, and the second dummy electrode 21 is provided on the protective layers 17 and 18, respectively.

  The first dummy electrode 20 is formed in a rectangular shape extending along the XY plane and having sides parallel to the X axis and the Y axis. The first dummy electrodes 20 are disposed at positions adjacent to the end surfaces T1 and T2 of the side margin portion 25, respectively. In other words, the first dummy electrode 20 is disposed at the four corners where the end margin portion 24 and the side margin portion 25 of the electrode layer 16 intersect.

  More specifically, the first dummy electrode 20 is formed on the first edge E1 along two sides parallel to the Z-axis direction of the first end surface T1 and on two sides parallel to the Z-axis of the second end surface T2. It is provided in the 2nd ridge part E2 along. The first dummy electrode 20 is exposed at the first end surface T1 and the side surfaces S1, S2 at the first ridge portion E1, and is exposed at the second end surface T2 and the side surfaces S1, S2 at the second ridge portion E2.

  As one aspect, the first dummy electrode 20 is stacked in the Z-axis direction along the ridges E1 and E2. The position of each first dummy electrode 20 in the Z-axis direction matches the position of each internal electrode 12, 13 in the Z-axis direction. The first dummy electrode 20 located at the same position in the Z-axis direction and the internal electrodes 12 and 13 are separated from each other in the Y-axis direction, and the first dummy electrodes 20 located at the same position in the Z-axis direction are separated from each other in the X-axis direction. Yes.

  In the multilayer capacitor 10 of this aspect, the distance between the internal electrodes 12 and 13 and the first dummy electrode 20 having a different pole from the internal electrodes 12 and 13 is larger than the thickness of the dielectric layer. That is, the distance between the first internal electrode 12 and the first dummy electrode 20 on the second external electrode 15 side is larger than the thickness of the dielectric layer. Further, the distance between the second internal electrode 13 and the first dummy electrode 20 on the first external electrode 14 side is larger than the thickness of the dielectric layer.

  As a result, the distance between the internal electrodes 12 and 13 and the first dummy electrode 20 having a different pole from the internal electrodes 12 and 13 is appropriately ensured, so that the breakdown voltage of the multilayer capacitor 10 is reduced. Can be suppressed.

  In addition, the 1st dummy electrode 20 should just be arrange | positioned in the side surface S1, S2 side of the laminated body 11 rather than the extension line (two-dot chain line L in FIG. 7A) of the edge part of the internal electrodes 12 and 13. FIG. Accordingly, the first dummy electrode 20 may be disposed so as to be within the end margin portion 24 where the internal electrodes 12 and 13 do not exist.

  Further, the shape of the first dummy electrode 20 is not limited to a rectangular shape. For example, as shown in FIG. 7B, the first dummy electrode 20 may have a triangular shape. In this case, even when the widths of the end margin portion 24 and the side margin portion 25 are reduced, the distance between the top portions of the internal electrodes 12 and 13 and the triangular first dummy electrode 20 can be maintained. It is possible to suppress a decrease in pressure resistance.

  Furthermore, as shown to FIG. 7C, the extraction | drawer part of the internal electrodes 12 and 13 and the 1st dummy electrode 20 of the same polarity may be connected. In this case, the internal electrodes 12 and 13 are integrated with the first dummy electrode 20 to form a T shape. Thereby, since the density of the laminated body 11 improves, it can prevent that the laminated body 11 wears too much, and can further suppress the fall of the pressure | voltage resistance of the multilayer capacitor 10. FIG.

  The shape of the first dummy electrode 20 can be arbitrarily determined so that the first dummy electrode 20 is separated from the internal electrodes 12 and 13 in the Y-axis direction and the first dummy electrodes 20 are separated from each other in the X-axis direction. It is.

  The second dummy electrode 21 is formed in a rectangular shape extending along the XY plane and having sides parallel to the X axis and the Y axis. The second dummy electrodes 21 are arranged at positions adjacent to the end faces T1 and T2 of the protective layers 17 and 18, respectively, and face each other in the X-axis direction. In other words, the second dummy electrode 21 is disposed in a region above and below the Z-axis direction of the end margin portion 24 of the electrode layer 16.

  More specifically, the second dummy electrode 21 is formed on the third edge E3 along two sides parallel to the Y-axis direction of the first end surface T1 and on two sides parallel to the Y-axis of the second end surface T2. It is provided in the 4th ridge part E4 along. The second dummy electrode 21 extends over the entire width of the ridges E3 and E4 in the Y-axis direction. Therefore, the second dummy electrode 21 is exposed to the first end face T1 and the side surfaces S1, S2 at the third ridge E3, and is exposed to the second end face T2, and the side faces S1, S2 at the fourth ridge E4. .

  That is, the second dummy electrode 21 is continuous from one side surface S1 (S2) of the multilayer body 11 to the other side surface S2 (S1). The second dummy electrode 21 is formed in a rectangular shape so as to cover the uppermost and lowermost internal electrodes 12 and 13 in the Z-axis direction, and suppresses the protective layers 17 and 18 from being excessively worn. Thereby, the fall of the pressure | voltage resistance between the external electrodes 14 and 15 and the internal electrodes 12 and 13 of the Z-axis direction uppermost part and the lowest part can be suppressed.

  Further, since the multilayer capacitor 10 has a configuration in which a plurality of second dummy electrodes 21 are present in the protective layers 17 and 18, wear of the protective layers 17 and 18 is further suppressed. It is possible to further suppress a decrease in pressure resistance between the uppermost and lowermost internal electrodes 12 and 13 in the axial direction.

  As shown in FIGS. 2, 3, 4, and 6, the second dummy electrode 21 is stacked in the Z-axis direction along the end faces T1 and T2. In the present embodiment, two layers of second dummy electrodes 21 are provided on the protective layers 17 and 18 respectively. The second dummy electrodes 21 located at the same position in the Z-axis direction are separated from each other in the X-axis direction. The shape of each second dummy electrode 21 can be determined as appropriate so that the second dummy electrodes 21 are separated from each other in the X-axis direction.

  The dummy electrodes 20 and 21 are made of the same metal material as the internal electrodes 12 and 13. The internal electrodes 12 and 13 and the dummy electrodes 20 and 21 can be formed of, for example, nickel (Ni) or copper (Cu). In this case, the shrinkage of the internal electrodes 12 and 13 during firing and the shrinkage of the dummy electrodes 20 and 21 are approximately the same, so that an effect of preventing the occurrence of cracks during firing is obtained. The internal electrodes 12 and 13 and the dummy electrodes 20 and 21 may be constituted by a plurality of layers formed of different metal materials.

  As described above, barrel polishing is performed on the multilayer body 11 before the external electrodes 14 and 15 are provided in the manufacturing process of the multilayer capacitor 10. In barrel polishing, the top portion P of the multilayer body 11 or the multilayer body is performed. The ridges along each side of 11 are easily worn. In particular, in the multilayer capacitor 10, when the ridges E1 and E3 on the first end face T1 side of the multilayer body 11 and the ridge parts E2 and E4 on the second end face T2 side of the multilayer body 11 are excessively worn, a breakdown voltage failure occurs. It becomes easy.

  That is, on the first end face T1 side of the multilayer body 11, when the first ridge E1 is excessively worn, the distance d1 between the first ridge E1 and the second internal electrode 13 shown in FIG. Further, when the third ridge E3 is excessively worn, the distance d3 between the third ridge E3 and the second internal electrode 13 shown in FIG. In these cases, the first external electrode 14 and the second internal electrode 13 are close to each other.

  On the second end face T2 side of the multilayer body 11, when the second ridge E2 is excessively worn, the distance d2 between the second ridge E2 and the first internal electrode 12 shown in FIG. 7A becomes narrow. Further, when the fourth ridge E4 is excessively worn, the distance d4 between the fourth ridge E4 and the first internal electrode 12 shown in FIG. In these cases, the second external electrode 15 and the first internal electrode 12 are close to each other.

  In such a case, in the multilayer capacitor 10, when the insulation by the end margin portion 24 and the protective layers 17 and 18 becomes insufficient, the first external electrode 14 and the second internal electrode 13, and the second external electrode A breakdown voltage failure occurs between the first internal electrode 12 and the first internal electrode 12.

  In particular, in the multilayer capacitor 10 that is used at a high voltage as in the present embodiment, the voltage applied between the external electrodes 14 and 15 becomes high, and therefore, between the first external electrode 14 and the second internal electrode 13, and the first 2 Discharge easily occurs between the external electrode 15 and the first internal electrode 12. Therefore, the wear amount of the ridges E1, E2, E3, and E4 of the laminated body 11 due to barrel polishing needs to be further suppressed.

  In that respect, in the multilayer capacitor 10 according to the present embodiment, the dummy electrodes 20 and 21 are arranged on the ridges E1, E2, E3, and E4 of the multilayer body 11. Since the dummy electrodes 20 and 21 are formed of a metal material having a higher Young's modulus than the ceramics constituting the multilayer body 11, the multilayer capacitor 10 wears the ridges E1, E2, E3, and E4 of the multilayer body 11 by barrel polishing. The amount is suppressed.

  Furthermore, the ridges E1, E2, E3, and E4 of the multilayer body 11 have a higher density than other portions of the multilayer body 11 due to the presence of the dummy electrodes 20 and 21. Therefore, since the ridges E1, E2, E3, and E4 of the multilayer body 11 have high strength, the multilayer capacitor 10 effectively suppresses the wear amount of the ridges E1, E2, E3, and E4 of the multilayer body 11 due to barrel polishing. Is done.

  As described above, in the multilayer capacitor 10 according to the present embodiment, the wear amount of the ridges E1, E2, E3, and E4 of the multilayer body 11 due to barrel polishing is effectively suppressed. Insulation between the internal electrode 13 and insulation between the second external electrode 15 and the first internal electrode 12 are ensured. Therefore, the multilayer capacitor 10 is unlikely to have a breakdown voltage failure.

  As a comparative example, a multilayer capacitor was manufactured without providing the dummy electrodes 20 and 21 according to the present embodiment. When 10,000 such multilayer capacitors were produced, a breakdown voltage defect occurred in the three multilayer capacitors. On the other hand, when 10,000 multilayer capacitors 10 according to the present embodiment were produced, no breakdown voltage occurred in any of the multilayer capacitors 10. As described above, the multilayer capacitor 10 according to the present embodiment can provide a high manufacturing yield.

  Further, in the multilayer capacitor 10 according to the present embodiment, since the ridges E1, E2, E3, and E4 of the multilayer body 11 have high strength, the ridges E1, E2, and the like due to an impact applied to the multilayer body 11 during the manufacturing process. E3 and E4 are not easily damaged. Therefore, in the multilayer capacitor 10, not only at the time of barrel polishing but also in the entire manufacturing process, a breakdown voltage failure due to damage to the ridges E1, E2, E3, E4 of the multilayer body 11 is unlikely to occur.

  In addition, since the abrasion amount of the protective layers 17 and 18 by barrel grinding | polishing is suppressed, so that the 2nd dummy electrode 21 in each protective layer 17 and 18 is laminated | stacked on the Z-axis direction, the protective layers 17 and 18 are suppressed. It is preferable that a plurality of layers of second dummy electrodes 21 be arranged for each. However, if at least one second dummy electrode 21 is disposed on each of the protective layers 17 and 18, the above effect can be obtained.

  In the multilayer capacitor 10 according to the present embodiment, the manufacturing cost can be reduced by forming the dummy electrodes 20 and 21 together with the internal electrodes 12 and 13. Therefore, the dummy electrodes 20 and 21 are preferably formed of the same metal material as the internal electrodes 12 and 13. However, if the dummy electrodes 20 and 21 are made of a metal material having a higher Young's modulus than the ceramics constituting the multilayer body 11, the above-described effect can be obtained.

  Furthermore, as described above, the dummy electrodes 20 and 21 do not have a function of generating an electrical connection unlike the internal electrodes 12 and 13, and therefore may not be formed of a metal material having a low electrical resistance. That is, the dummy electrodes 20 and 21 may be configured as a dummy member formed of a material other than a metal material. Furthermore, the first dummy electrode 20 and the second dummy electrode 21 may be formed of different materials.

  The multilayer capacitor 10 according to this embodiment can also take the following aspects. As the internal electrodes 12 and 13, a first internal electrode 12 and a second internal electrode 13 are provided, and first dummy electrodes 20 are formed at four corners of the first internal electrode 12. The first dummy electrode 20 may be formed at the corner. Further, the second dummy electrode 21 may be formed on the first end surface T1 of the multilayer body 11, and the second dummy electrode 21 may be formed on the second end surface T2 of the multilayer body 11. Desirably, a plurality of second dummy electrodes 21 may be formed on the first end surface T1 of the multilayer body 11, and a plurality of second dummy electrodes 21 may be formed on the second end surface T2 of the multilayer body 11.

[Method of Manufacturing Multilayer Capacitor 10]
FIG. 9 is a flowchart showing a method for manufacturing the multilayer capacitor 10 according to the present embodiment. 10 to 16 are diagrams showing a manufacturing process of the multilayer capacitor 10. Hereinafter, a method for manufacturing the multilayer capacitor 10 will be described with reference to FIGS.

(Step ST01: Preparation of ceramic sheet)
A ceramic sheet 110U for forming the electrode layer 16 and the protective layers 17 and 18 is prepared. The ceramic sheet 110U is configured as an unfired dielectric green sheet.

  The ceramic sheet 110U can be formed into a sheet shape using, for example, a roll coater. The ceramic sheet 110U is not cut for each multilayer capacitor 10, and the following steps ST02 to ST04 can be performed collectively for the plurality of multilayer capacitors 10.

(Step ST02: electrode printing)
In step ST02, unfired internal electrodes 12U and 13U and dummy electrodes 20U and 21U to be the internal electrodes 12 and 13 and the dummy electrodes 20 and 21 are formed on the upper surface in the Z-axis direction of the ceramic sheet 110U, and the first sheet 112U is formed. Then, the second sheet 113U and the third sheet 114U are produced. The unfired internal electrodes 12U and 13U and the dummy electrodes 20U and 21U are collectively formed of the same kind of metal material using, for example, a screen printing method.

  10 is a plan view showing an upper surface in the Z-axis direction of the first sheet 112U, FIG. 11 is a plan view showing an upper surface in the Z-axis direction of the second sheet 113U, and FIG. 12 is an upper surface in the Z-axis direction of the third sheet 114U. FIG.

As shown in FIG. 10, the first sheet 112 </ b> U is formed with an unfired first internal electrode 12 </ b> U that becomes the first internal electrode 12 and an unfired first dummy electrode 20 </ b> U that becomes the first dummy electrode 20. The
As shown in FIG. 11, the second sheet 113U is formed with an unfired second internal electrode 13U that becomes the second internal electrode 13 and an unfired first dummy electrode 20U that becomes the first dummy electrode 20. The
As shown in FIG. 12, unfired second dummy electrode 21U to be second dummy electrode 21 is formed on third sheet 114U.

(Step ST03: Lamination)
As shown in FIG. 13, the sheets 112U, 113U, and 114U are stacked. The first sheets 112U and the second sheets 113U are alternately arranged in the Z-axis direction. The third sheet 114U is disposed at the upper and lower parts in the Z-axis direction with the first sheet 112U and the second sheet 113U sandwiched in the Z-axis direction. In addition, a ceramic sheet 110U on which no electrode is formed is disposed at the top in the Z-axis direction.

  The number of the first sheets 112U and the second sheets 113U can be appropriately determined according to the number of dielectric layers in the multilayer capacitor 10. Further, the number of sheets 114 can be appropriately determined according to the thickness of the protective layers 17 and 18 in the multilayer capacitor 10.

  In FIG. 13, for convenience of explanation, the sheets 112U, 113U, 114U, and 110U are shown in a state where each multilayer capacitor 10 is cut. However, from the viewpoint of work efficiency and handling properties, it is preferable that the sheets 112U, 113U, and 114U can be separated for each multilayer capacitor 10 in a step after this step ST03 (in this embodiment, step ST05). .

(Step ST04: thermocompression bonding)
The laminated sheets 112U, 113U, 114U are thermocompression bonded. Thereby, the some sheet | seat 112U, 113U, 114U is integrated, and the lamination sheet by which the some unfired laminated body 11U was arranged is obtained. As a thermocompression bonding method, for example, an isostatic pressing method can be used.

  Since the internal electrodes 12U and 13U and the dummy electrodes 20U and 21U are printed on the upper surface in the Z-axis direction of the ceramic sheet 110U, they slightly protrude from the upper surface in the Z-axis direction of the ceramic sheet 110U. For this reason, when the sheets 112U, 113U, and 114U are thermocompression bonded, the pressure at the portion where the internal electrodes 12U and 13U and the dummy electrodes 20U and 21U protrude is increased.

  Therefore, in the laminated sheet obtained in step ST04, the portions where the internal electrodes 12U and 13U and the dummy electrodes 20U and 21U are arranged have a particularly high density.

(Step ST05: Dicing)
The laminated sheet obtained in step ST04 is cut into each unfired laminated body 11U that becomes each laminated body 11 by dicing.

  FIG. 14 is a perspective view of the unfired laminated body 11U obtained in step ST05. In the laminated body 11U, the sheets 112U and 113U are the electrode layers 16U, and the sheet 114U is the protective layers 17U and 18U.

  The first internal electrode 12U is exposed at the first end face T1U of the electrode layer 16U, and the second internal electrode 13U is exposed at the second end face T2U of the electrode layer 16U. The dummy electrodes 20U and 21U are exposed on the end faces T1U and T2U and the side faces S1U and S2U.

  In the electrode layer 16U obtained in this step ST05, the density of the ridges E1U, E2U, E3U, E4U where the dummy electrodes 20U, 21U are arranged is higher than that of a general electrode layer where the dummy electrodes 20U, 21U are not arranged. . Thereby, in the multilayer capacitor 10 manufactured in the present embodiment, the density of the ridges E1, E2, E3, E4 of the multilayer body 11 is increased.

(Step ST06: Barrel polishing)
For the purpose of smoothing the surface, deburring, chamfering, etc., the laminated body 11U shown in FIG. 14 is subjected to barrel polishing. Thereby, the laminated body 11U shown in FIG. 15 is obtained.

  By smoothing the end surfaces T1U and T2U of the multilayer body 11U by barrel polishing, the adhesion between the end surfaces T1U and T2U of the multilayer body 11 and the unfired external electrodes 14U and 15U is increased. Moreover, it is possible to prevent the stack 11U from being chipped or cracked by removing the burrs from the stack 11U and chamfering the top PU, the ridges E1U, E2U, E3U, E4U, and the like of the stack 11U. it can.

  On the other hand, since the dummy electrodes 20U and 21U are provided at the ridges E1U, E2U, E3U, and E4U of the multilayer body 11U, the amount of wear due to barrel polishing is suppressed. Therefore, in the multilayer capacitor 10 manufactured in this embodiment, the insulation between the first external electrode 14 and the second internal electrode 13 and the insulation between the second external electrode 15 and the first internal electrode 12 are performed. Therefore, the breakdown voltage is less likely to occur.

(Step ST07: binder removal processing)
A binder removal process is performed by heating the laminated body 11U after barrel polishing shown in FIG. The binder removal process is performed, for example, in a nitrogen atmosphere.

(Step ST08: Firing)
The laminated body 11U shown in FIG. 2 etc. is obtained by baking the laminated body 11U after a binder removal process. In the laminated body 11U, the internal electrodes 12U and 13U and the dummy electrodes 20U and 21U are formed of the same kind of metal material. Therefore, in this step ST08, the internal electrodes 12U and 13U and the dummy electrodes 20U and 21U are sintered in the same manner. Shows behavior. Therefore, cracks and the like are unlikely to occur in the fired laminate 11.

(Step ST09: Annealing)
The laminated body 11 after firing is annealed by heating. Annealing is performed in a reducing atmosphere, for example.

(Step ST10: Reoxidation treatment)
The laminated body 11 after annealing is reoxidized by heating. The reoxidation process is performed in an oxidizing atmosphere.

(Step ST11: External electrode formation)
As shown in FIG. 16, the multilayer capacitor 10U is obtained by applying the paste-like external electrodes 14U and 15U to be the external electrodes 14 and 15 to the multilayer body 11 after the reoxidation treatment. Then, the paste-like external electrodes 14U and 15U formed on the multilayer capacitor 10U are baked on the multilayer body 11.

  Thus, the multilayer capacitor 10 according to this embodiment shown in FIG. 1 and the like is obtained.

  The embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Multilayer capacitor 11 ... Laminated body 12 ... 1st internal electrode 13 ... 2nd internal electrode 14 ... 1st external electrode 15 ... 2nd external electrode 16 ... Electrode layer 17 ... 1st protective layer 18 ... 2nd protective layer 20 ... 1st dummy electrode 21 ... 2nd dummy electrode E1, E2, E3, E4 ... Edge part T1, T2 ... End surface S1, S2 ... Side surface

Claims (6)

Internal electrodes and dielectric layers alternately stacked in a first direction, protective layers disposed on both sides of the first direction, a first surface facing the first direction, and orthogonal to the first direction A second surface facing the second direction, a third surface facing the third direction orthogonal to the first and second directions, and a ridge connecting the first surface and the second surface. A laminate having
An external electrode that covers the second surface and is connected to the internal electrode;
A plurality of dummy electrodes exposed on the second and third surfaces;
The plurality of dummy electrodes includes a plurality of second dummy electrodes that are disposed on the protective layer and exposed on the second surface of the inner electrode adjacent to the protective layer that is not exposed,
All the said several 2nd dummy electrodes are arrange | positioned between the said edge part and the said ridge part nearest to the said edge part. Multilayer capacitor. The multilayer capacitor according to claim 1,
A multilayer capacitor in which the protective layer includes a dielectric layer and the second dummy electrode. The multilayer capacitor according to claim 1, wherein the dummy electrode includes a first dummy electrode provided on the third surface side of the internal electrode. The multilayer capacitor according to claim 3,
The distance between the internal electrode and the first dummy electrode spaced from the internal electrode is
A multilayer capacitor having a thickness greater than that of the dielectric layer. The multilayer capacitor according to claim 3 or 4,
The internal capacitor, the first dummy electrode, and the second dummy electrode are formed of the same kind of metal material. A multilayer capacitor according to any one of claims 3 to 5,
The first dummy electrode is a multilayer capacitor formed in a triangular shape.

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